Paper Jams July 25, 2026 by Editor Team

Konica Minolta bizhub — Paper Jam Code 20-01: Misfeed at Vertical Transport Section

Paper Jam Code 20-01 is a primary misfeed in the vertical transport section on Konica Minolta bizhub machines. Konica Minolta service documentation classifies all 20-xx codes under the heading Misfeed at Vertical Transport Section — a category covering every fault type that occurs in the shared paper transport path between the source tray exits and the registration area. The -01 suffix carries a precise mechanical meaning: paper was successfully detected leaving its source tray but failed to reach the vertical transport section sensor (or registration sensor) within the specified timing window. This is a genuine mechanical paper transport failure occurring after a successful tray feed — not a tray pickup failure, not a board-level synchronization fault.

The official Konica Minolta description states precisely:

Paper fed from any paper source was not detected at the vertical transport sensor (or registration sensor) within the specified time after the paper was confirmed to have left the source tray feed section.

Translated into field language: the machine initiated a print job. Paper was fed from the selected source tray — the source tray feed sensor confirmed that the paper leading edge successfully exited the tray’s feed nip and entered the vertical transport section. However, the next sensor downstream in the paper path — either an intermediate vertical transport (VT) sensor or the registration sensor itself, depending on model — did not detect the paper within the timing window calibrated for the vertical transport section travel distance. The paper stalled somewhere between the source tray exit and the next detection point. The machine recorded 20-01.

The critical structural insight that separates 20-01 from every tray-sourced -01 code in the bizhub jam code family is this: by the time 20-01 fires, the source tray’s mechanical feed mechanism has already performed correctly. The paper left the tray. The tray feed sensor confirmed it. 20-01 is not a tray pickup failure — it is a failure of the shared vertical transport section that receives paper from every tray source and carries it upward to the registration area. This distinction has immediate diagnostic consequences: the feed rollers, feed clutches, separation rollers, and elevator mechanism of the source tray are not suspects for 20-01. The vertical transport rollers, the vertical transport motor drive train, the transport section guide plates, and the VT section sensors are the entire diagnostic focus.

20-01 is also the only standard jam code in the bizhub family where a single mechanical failure can simultaneously affect every paper source on the machine. Because all tray sources deliver paper to the same shared vertical transport section, a failed VT transport motor, a seized VT drive gear, or a VT roller nip blocked by a paper fragment produces 20-01 from Tray 1, Tray 2, Tray 3, Tray 4, and the LCT simultaneously — on every print attempt from every source. This multi-source failure pattern is 20-01’s most diagnostically distinctive characteristic and immediately identifies the shared VT section as the fault location without requiring tray-by-tray investigation.

FieldDetails
Jam Code20-01
KM Category HeadingMisfeed at Vertical Transport Section — the 20-xx category covers all fault types in the shared vertical transport section between source tray exits and the registration area. The -01 suffix specifically means primary misfeed: paper successfully left the source tray but was not detected at the VT section sensor or registration sensor within the timing window. This is a mechanical paper transport failure in the shared transport path
Critical distinction from source-tray -01 codes (11-01, 12-01, 13-01, 14-01, 16-01)Source-tray -01 codes mean paper never left the source tray — the tray feed mechanism failed. 20-01 means paper DID leave the source tray (confirmed by the source tray feed sensor) but stalled in the vertical transport section before reaching the next detection sensor. The tray pickup roller, tray feed clutch, tray separation roller, and elevator (for LCT) are all confirmed functional by the source tray exit sensor triggering. Do not replace tray feed components to resolve 20-01
Critical distinction from 20-4020-40 is a WTEN image write signal timeout occurring in the context of a vertical transport section feed — paper reached the registration sensor on time but the WTEN signal was not issued. Board-level synchronization failure. 20-01 is the mechanical opposite: paper never reached the registration sensor or VT section sensor. Do not apply board-level, firmware, or HDD diagnostics to 20-01
Critical distinction from -02 registration loop forming codes (11-02, 12-02, etc.)The -02 codes mean paper reached the registration area but arrived after the registration timing window had commenced — paper is found buckled or crumpled at the registration nip. 20-01 means paper stalled in the transport section before reaching the registration area — paper is found in the VT section, not at the registration nip. Paper condition (clean vs. crumpled) and stop position confirm the difference
Detection Logic — MFPB platform (C258 / C368 / C458 / C658 / 368e / 658e / C450i / C550i / C650i):After the source tray feed sensor (PS2, PS3, or PS4 — Tray 2, 3, 4 exit sensors respectively) confirmed paper departure from the source tray section, the vertical transport sensor or registration sensor (PS1 / PS72) was not triggered within the specified timing count. On single-VT-sensor models, the registration sensor IS the VT section endpoint sensor. On models with intermediate VT sensors (PS_VT), the intermediate sensor triggers first; failure to trigger the intermediate sensor within its window fires 20-01 before the registration sensor window even begins
Detection Logic — BASEB models (C250i / C300i / C360i / C3350i / C4050i):After paper departure from the source tray section was confirmed by the relevant tray exit sensor (PS2 for Tray 2, PS3 for Tray 3), the registration sensor (PS1 or PS9) was not triggered within the VT section timing window. BASEB platform bizhub models typically do not have a separate intermediate VT sensor — the registration sensor (PS1 or PS9) serves as the sole endpoint detection for the VT section timing window on most BASEB configurations
Detection Logic — PFTDB models (654e / 754e / 758 / 808 / 958 / C659 / C759):Paper departure from the source tray section was confirmed by the relevant tray sensor (PS6 for T2, PS7 for T3, PS8 for T4). The vertical transport intermediate sensor (PS38 for T2 VT path, PS39 for T3 VT path, PS40 for T4 VT path, or the registration sensor PS4 as the final endpoint) was not triggered within the VT timing window. PFTDB models have the most elaborate VT sensor chain of any platform — each tray source has a dedicated VT path sensor in addition to the shared registration sensor at the top
Key ComponentsVertical transport motor (M1 on MFPB/BASEB/PRCB platforms; M22 or M1 on PFTDB platform — primary drive motor for all VT section transport rollers); VT section transport rollers / relay rollers (multiple pairs of driven rollers and spring-loaded pinch rollers throughout the vertical transport path); VT motor drive train (timing belt from M1/M22 to main drive shaft; gear train from main drive shaft to individual VT roller shafts); VT intermediate sensor(s) (PS_VT / PS38 / PS39 / PS40 / model-specific — detects paper passing through the VT section mid-path); registration sensor (PS1 / PS9 / PS4 — final VT section endpoint detection sensor, also the registration area entry sensor); VT section guide plates (upper and lower paper path guides throughout the vertical transport section); engine control board (BASEB / MFPB / FRB / PFTDB — controls VT motor and reads VT sensors)
SeverityHigh — all paper sources that route through the affected VT section are disabled; when the VT motor or a shared VT roller nip fails, every paper source produces 20-01 simultaneously; when a specific VT path segment fails (affecting only papers from certain lower trays), only those sources produce 20-01; paper found in the VT section, typically clean and undamaged (stalled transport) or lightly crumpled at a blockage point
Related Jam Codes20-40 (VT section WTEN image write signal timeout — board-level fault, paper reached registration sensor on time), 20-02 (VT section late arrival at registration — paper traversed the VT section but arrived too slowly for correct loop forming), 11-01 / 12-01 / 13-01 / 14-01 (source tray misfeeds — paper never left the source tray, for comparison), 11-02 / 12-02 (registration loop forming failures — paper arrived at registration but arrived late), 16-01 (LCT misfeed — paper never left the LCT cassette)

All Affected Models and Vertical Transport Section Component References

Jam Code 20-01 applies to all bizhub models with a defined vertical transport section — any model with paper sources below the registration area that must transport paper upward through a shared transport section. On models where Tray 1 exits directly adjacent to the registration area (very short paper path), the VT section may be minimal; on models with extended cassette configurations or high-volume paper paths, the VT section is substantial and has dedicated intermediate sensors. The VT motor designation (M1 or M22) and the VT intermediate sensor designations are the most diagnostically critical component references for 20-01.

bizhub ModelsVT MotorVT Motor Check Code / ConnectorVT Intermediate Sensor(s)VT Sensor Connector(s)Registration Sensor (VT Endpoint)Reg. Sensor ConnectorVT Drive TypeControlling Board
C250i / C300i / C360i / 250i / 300i / 360iM1 (main transport motor)CC:40 MC:1,4,5 — BASEB CN19EA-1 to 5, 1-CNone (single VT path — PS1 is endpoint)—PS1BASEB CN15E-9 (ON), 4-CGear train from M1 to VT roller shafts via main drive assemblyBASEB
C3350i / C4000i / C4050iM1 (main transport motor)CC:40 MC:1,2 — BASEB CN17E-1 to 5, 1-CNone standard (PS9 is endpoint); some configurations have PS_VT — refer to SMRefer to SMPS9BASEB CN22EA-13 (ON), 13-CGear train from M1 via main drive assemblyBASEB
C258 / C308 / C368 / C227 / C287 / C367M1 (main transport motor)CC:40 MC:1 — MFPB CN8E-3, 2-CNone standard (PS1 is endpoint); refer to SM for model variantsRefer to SMPS1FRB CN8-3 (ON), 6-LTiming belt M1 → main shaft; gears to VT rollersMFPB + FRB
368e / 308eM1 (main transport motor)CC:40 MC:1–4 — MFPB CN8E-3, 2-CNone standard (PS1 is endpoint)—PS1FRB CN8-3 (ON), 6-LTiming belt M1 → main shaft; gears to VT rollersMFPB + FRB
C458 / C558 / C658M1 (main transport motor)CC:40 MC:1–4 — MFPB CN14E-3, 1-CPS_VT (where fitted — refer to SM); PS1 or PS72 is endpointEXCB CN6 series — refer to SMPS1 (C458 / C558) / PS72 (C658)EXCB CN6-3 (ON), 26-PTiming belt M1 → main shaft; gears to VT roller shafts via right-side drive assemblyMFPB + FRB + EXCB
458e / 558e / 658eM1 (main transport motor)CC:40 MC:1–4 — MFPB CN14E-3, 1-CPS_VT (where fitted — refer to SM)Refer to SMPS1 (458e / 558e) / PS72 (658e)EXCB CN6-3 (ON), 26-PTiming belt M1 → main shaft; gear train to VT rollersMFPB + FRB + EXCB
C450i / C550i / C650i / 458i / 558i / 658iM1 (main transport motor)Refer to SMPS_VT (refer to SM)Refer to SMPS1Refer to SMTiming belt and gear train from M1 — refer to SMMFPB + EXCB + FRB + BASEB
C224e / C284e / C364e / C224 / C284 / C364M1 (main transport motor)Refer to SM (PRCB or MFPB)Refer to SMRefer to SMPS1Refer to SMGear train from M1 — refer to SMPRCB / MFPB
C454 / C554 / 223 / 283 / 363 / 423M1 (main transport motor)Refer to SM (PRCB)Refer to SMRefer to SMPS1Refer to SMGear train from M1 — refer to SMPRCB
654e / 754eM22 (vertical transport motor) + M1 (main transport)M22: PFTDB CN10-1 to 4, 13-P; M1: refer to SMPS38 (T2 VT path) / PS39 (T3 VT path) / PS40 (T4 VT path) — PFTDB CN14 series — refer to SMPFTDB CN14 series — refer to SMPS4 (registration sensor)PFTDB CN14-8 (ON), 1-PM22 dedicated VT belt drive; M1 gear train to upper transport — refer to SMPFTDB + MFPB
758 / 808 / 958 / PRO 958M22 (vertical transport motor) + M1 (main transport)M22: PFTDB CN10-1 to 4, 13-P; M1: refer to SMPS38 (T2 VT) / PS39 (T3 VT) / PS40 (T4 VT) / model-specific — refer to SMPFTDB CN12 series — refer to SMPS4PFTDB CN12-10 (ON), 3-PM22 dedicated VT belt drive; M1 drives upper section — refer to SMPFTDB + MFPB
C659 / C759M22 (VT motor) + M1Refer to SMPS38 / PS39 / PS40 or model-specific — refer to SMRefer to SMPS4PFTDB CN14-8 (ON), 1-PM22 VT belt drive; M1 upper section — refer to SMPFTDB + MFPB

CC = Check Code, MC = Multi Code. VT = Vertical Transport. M22 is a dedicated vertical transport motor on PFTDB platform models — on MFPB and BASEB platform models, M1 drives all transport functions including the VT section. Intermediate VT sensor designations (PS38, PS39, PS40 on PFTDB platform) correspond to the tray-level VT sections discussed in the 12-40, 13-40, and 14-40 jam code articles. Confirm all connector references in the model-specific service manual before performing I/O checks.

ℹ️ The critical 20-01 diagnostic split — all sources vs. single source: Before any hardware inspection, determine whether 20-01 fires from every paper source or only from specific sources. If 20-01 fires from all paper sources simultaneously (switching between Tray 1, Tray 2, and any other source all produce 20-01): the fault is in the shared VT section used by every source — VT motor failure, seized VT drive gear, timing belt failure, or a paper fragment blocking the main VT roller nip. Begin at Step 5 (VT motor and drive train) and Step 4 (VT roller inspection). If 20-01 fires only from lower tray sources (Tray 3 and Tray 4 produce 20-01 but Tray 1 and Tray 2 do not): the fault is in the portion of the VT section that carries paper from the lower trays — the lower VT transport rollers, the lower VT path sensors, or the lower VT drive section. Paper from Tray 1 travels a shorter VT path than paper from Tray 3 or Tray 4 — a fault in the lower VT section affects only the longer paper paths. If 20-01 fires from one specific tray only: the fault may be at the transition point between that tray’s exit section and the shared VT path, or at a VT sensor that only monitors that tray’s paper path segment (particularly on PFTDB models with per-tray VT intermediate sensors PS38/PS39/PS40).

Understanding the Vertical Transport Section — Why 20-01 Occurs

The vertical transport (VT) section is the shared mechanical paper highway that serves every paper source on the machine. On bizhub machines with multiple paper trays, paper from each tray exits that tray’s feed section and merges into a common vertical transport path — a series of driven transport rollers and guide plates that carry the paper upward to the registration roller assembly at the top of the paper path. Unlike the source tray feed sections (which have dedicated rollers, clutches, and mechanisms for each tray), the vertical transport section is shared infrastructure: the same transport rollers and the same motor carry paper from Tray 1, Tray 2, Tray 3, Tray 4, and the LCT, one sheet at a time.

The VT section transport rollers — also called relay rollers or intermediate transport rollers in service documentation — are mechanically different from source tray feed rollers:

  • Function: Pure conveyance — they receive paper that has already been separated and fed by the source tray mechanism, and transport it upward at a consistent speed. They do not need to grip and separate paper from a stack; they only need to maintain sufficient nip force to move a single sheet at constant velocity
  • Drive architecture: All VT section transport rollers on a given machine are driven by a single motor — M1 on MFPB and BASEB platform machines, M22 (with M1 for the upper section) on PFTDB platform machines. The motor drives a timing belt to the main transport drive shaft, which distributes motion to individual roller shafts through a gear train. A failure at any point in this drive chain — the motor itself, the timing belt, or a gear in the drive train — stops all VT transport rollers simultaneously, producing 20-01 from every paper source
  • Nip mechanism: Each VT roller pair consists of a rubber-surfaced driven roller and a spring-loaded pinch (idler) roller pressed against it. The nip force is determined by the spring tension — as springs age and fatigue, nip force decreases. Unlike source tray feed rollers, which also need sufficient friction to overcome separation resistance, VT transport rollers only need to overcome guide plate friction and the weight of the paper in the vertical section. This means VT rollers typically last significantly longer than source tray feed rollers before producing failures

Six root cause categories produce 20-01, ordered from highest to lowest frequency in field-installed bizhub machines:

  • Category 1 — Paper jam fragment or foreign object lodged in a VT roller nip (most common cause of sudden-onset consistent 20-01): A paper fragment torn from a previous jam, or a foreign object (staple, paper clip, small piece of tape, folded corner) that has entered the paper path, becomes lodged in a VT roller nip. Every subsequent sheet driven into that nip impacts the lodged obstruction, folds against it, and stalls — producing 20-01 on every print attempt from any source that routes through the affected nip. This is the most common cause of 20-01 that appeared suddenly following a jam clearing event. The diagnostic signature is: 20-01 that was not occurring before a recent jam, appeared immediately after that jam was cleared, and now fires consistently on every print attempt. The fragment is always in the VT roller nip at the location where the previous jam was cleared — or just downstream of it, where a torn fragment was carried by the motion of clearing before catching
  • Category 2 — VT transport roller surface degradation (most common cause of gradual-onset 20-01): The rubber surface of one or more VT section driven rollers has worn or glazed below the friction threshold needed to maintain consistent transport velocity against guide plate resistance. Unlike source tray feed roller glazing (which produces outright feed failure because the roller cannot overcome separation resistance), VT roller glazing typically produces intermittent 20-01 first — the roller can still transport paper on most passes but fails intermittently when paper surface, humidity, or drive load varies slightly. Progressive VT roller glazing escalates from intermittent to consistent over weeks. The classic pattern: 20-01 starts at 1 in 100 sheets, escalates to 1 in 30 over six to eight weeks, then becomes consistent. VT rollers on machines above 500k total copies should be inspected as a priority on any intermittent 20-01 call
  • Category 3 — VT motor (M1 / M22) failure or drive timing belt failure: The vertical transport motor or its drive belt to the main transport shaft has failed. Because M1 on MFPB/BASEB platform machines drives not only the VT section but also the registration roller, the fuser transport, and the output transport, an M1 failure produces a cascade of jam codes simultaneously — 20-01 from every source plus jam codes in the registration area and the fuser exit section, all within the same print attempt. This multi-section simultaneous failure pattern is the diagnostic signature of M1 failure. A failed VT timing belt (which connects M1 to the main transport shaft) produces an identical pattern. On PFTDB platform machines, M22 drives the lower VT section specifically — an M22 failure produces 20-01 from lower tray sources (Tray 2, 3, 4) while Tray 1 (which uses a shorter path driven by M1’s upper section) may still function
  • Category 4 — VT drive gear failure (broken tooth or seized gear): A gear in the drive train between the main transport shaft and an individual VT roller shaft has a broken tooth or has seized. A broken gear tooth produces periodic transport failure — paper transport stalls once per gear revolution when the broken tooth passes the mesh point. This produces intermittent 20-01 with a print-count-dependent pattern: 20-01 on every Nth page (where N corresponds to the gear ratio), regardless of paper source. A seized gear stops all rollers downstream of the failure point — producing consistent 20-01 from all sources that route through the downstream VT section. Drive gear failure produces a distinctive sound during the transport phase — a repeated clicking or grinding at a fixed print interval
  • Category 5 — VT section guide plate dislodged or damaged: A guide plate in the vertical transport section has been displaced from its mounting — most commonly during a previous jam clearing where force was applied to the paper while it was wrapped around a guide — or has been bent or cracked. A dislodged guide plate creates a step or gap at its leading edge that catches the paper leading edge, folding the paper against the step and stopping transport. Unlike roller or motor failures, guide plate displacement typically produces 20-01 that appears immediately after a jam clearing event involving forceful paper removal, and produces a distinctive paper fold pattern (sharp leading-edge fold rather than a crumpled or gradual stall)
  • Category 6 — VT intermediate sensor failure or contamination (PFTDB models and any model with intermediate VT sensors): The VT intermediate sensor (PS38 / PS39 / PS40 on PFTDB models; PS_VT on applicable MFPB models) is contaminated with paper dust or has failed in the OFF state. Paper passes through the sensor successfully but the sensor does not detect it — the engine board logs a transport timing failure and reports 20-01. This category is uniquely identifiable by paper stop position: the paper is found downstream of the failed sensor (or even partially through the registration nip) rather than stalled in the transport section. This paper has transported correctly but was not detected. Sensor contamination is confirmed by inspecting the sensor window; sensor failure is confirmed by checking the sensor state in Service Mode while paper is manually inserted into the aperture

Step 1 — Clear the Paper, Confirm the Stop Position, and Classify the Fault Zone

The paper stop position when 20-01 fires is the most important single diagnostic data point available. It not only confirms the code classification but identifies the specific zone within the vertical transport section where the failure occurred, directing the repair to the correct component without requiring disassembly of the entire VT section.

  1. Open the right-side cover, the right lower cover, and any transport section access panels indicated by the operator panel jam indicator lights. On machines with extended lower cassette configurations, the jam indicator may illuminate multiple access points simultaneously — open all indicated panels before attempting paper removal
  2. Before removing the paper, note the exact position of the paper leading edge and trailing edge, and the physical condition of the paper:
    • Paper found in the lower VT section — leading edge has not yet reached the mid-VT area: The paper stalled shortly after leaving the source tray. This stop position implicates the lower VT transport rollers — the first one or two roller pairs in the shared VT section — or the transition guide plates at the source tray-to-VT section junction. This is the most common stop position for Category 1 (jam fragment) and Category 2 (roller glazing) causes. Inspect the VT roller nip at the leading-edge stop position first
    • Paper found in the mid-to-upper VT section — between the lower VT rollers and the registration area: The paper entered and traversed the lower VT section correctly but stalled in the mid or upper VT section. This stop position implicates a specific VT roller pair or guide plate in the mid-path, or a failed intermediate VT sensor. Note whether the paper is crumpled (indicating it drove into a blockage) or simply stalled in position (indicating transport force was lost — roller or motor issue)
    • Paper found at or partially through the registration nip but 20-01 logged (not a -02 code): The paper reached the registration area but was not detected by the registration sensor within the VT timing window — sensor failure or contamination (Category 6). This is the only stop position for 20-01 where paper is found at the registration area. Confirm the registration sensor state in Service Mode before concluding — a registration sensor stuck OFF produces this pattern
    • Paper found with a sharp leading-edge fold or accordion fold at a specific point: The paper drove into a physical obstruction — a paper fragment, foreign object, or dislodged guide plate — at the fold point. The fold location identifies the obstruction location precisely. Inspect the VT roller nip or guide plate at that exact point for the obstruction
    • No paper found in the machine — VT section clear: Either the paper ejected partially, a previous jam clearing removed all paper, or the VT sensor producing the timing failure is stuck ON (falsely reporting constant paper presence). Check the VT intermediate sensor and registration sensor states in Service Mode before attempting another print
    • Multiple jams — paper from two sequential print cycles both found in the VT section: A complete blockage exists in the VT section from the previous jam cycle. Clear the oldest (deepest) jam fragment first, then the more recent paper. After clearing, inspect the entire VT path for any residual fragment before closing any access panel
  3. Remove the jammed paper carefully, always pulling in the direction of paper travel. If the paper is tightly wrapped around a VT transport roller, do not force it — release the roller nip (if a pinch roller release lever is available for that section) before pulling. Forcing paper against a rotating or mechanically held roller risks tearing a fragment that creates a secondary obstruction
  4. After clearing the primary jam, search the entire VT section systematically for paper fragments. Use a flashlight to inspect every VT roller nip — a fragment as small as a 10mm torn strip lodged in a nip produces consistent 20-01 on every subsequent print. Pay particular attention to the nip zone at or immediately downstream of where the original jam was cleared, as this is where torn fragments are most commonly left behind
  5. Inspect all visible guide plates for displacement — confirm that each guide plate is seated in its mounting tabs on both ends, flat against the adjacent guide surface, with no step or gap at either edge

Step 2 — Review Service History and Establish the Fault Pattern

The service history and fault pattern provide essential context that directs the diagnostic effort to the correct cause category before any component is inspected or replaced.

  1. Access the Error History log in Service Mode. Review the last 20–50 logged events:
    • 20-01 appeared immediately after a jam clearing event (same session, first print after the jam): A paper fragment left in the VT section from the previous jam is the primary suspect — Category 1. Inspect every VT roller nip systematically before any other action. The fragment is almost always within 50mm downstream of where the previous jam was reported to have stopped
    • 20-01 was not present before a specific maintenance event (roller replacement, cover replacement, transport section cleaning): A guide plate displaced during the maintenance activity, or a retaining clip from a replaced roller left in the transport path. Inspect the VT section at the location of the maintenance activity for displaced guides or foreign objects
    • 20-01 appearing intermittently with escalating frequency over weeks: Classic progressive VT roller glazing pattern — Category 2. Check VT roller copy counter and inspect VT roller surfaces
    • 20-01 appearing simultaneously from all paper sources, with concurrent jam codes in the registration area or fuser section: VT motor (M1) failure or timing belt failure — Category 3. Proceed directly to Step 5 (VT motor verification)
    • 20-01 appearing at a fixed periodic rate — every Nth page regardless of source: VT drive gear with a broken tooth — Category 4. Listen for a periodic clicking sound during transport. The interval between 20-01 occurrences corresponds to the gear’s rotational period
    • 20-01 with paper found at or near the registration sensor, paper transport appears correct: VT intermediate sensor or registration sensor contamination or failure — Category 6. Proceed to Step 7 (sensor verification)
  2. Check the total copy counter and cross-reference with the last VT section roller replacement or PM service record. VT transport rollers are typically rated for 300,000–500,000 copies at the machine PM interval, but this varies by model. On high-duty-cycle machines above 600k copies with no recorded VT roller replacement, roller wear is a primary suspect regardless of the immediate trigger event
  3. Determine the fault scope: does 20-01 fire from all paper sources or only from specific sources? Switch paper sources and run a 5-page test from each:
    • 20-01 from all sources → shared VT section fault (motor, timing belt, main drive gear, upper VT roller nip obstruction). Proceed to Steps 5 and 4
    • 20-01 from lower sources only (Tray 3 / Tray 4 / LCT, with Tray 1 / Tray 2 printing normally) → lower VT section fault (lower VT rollers, lower VT path sensor, lower VT drive section). The longer paper path from lower trays is affected; the shorter Tray 1/2 path bypasses the faulty zone
    • 20-01 from one specific source only → the fault is at the transition point between that tray’s exit section and the shared VT path, or at a VT sensor specific to that tray’s paper path segment (PS38 for Tray 2, PS39 for Tray 3, PS40 for Tray 4 on PFTDB models). Inspect the transition guide at that tray’s VT entry point and verify the tray-specific VT sensor in Service Mode

Step 3 — Confirm Paper Condition and Eliminate Paper-Related Causes

Paper condition contributes to VT section transport failures when static charge, excessive moisture, or paper weight creates additional resistance in the transport section that marginal rollers cannot overcome. On machines where VT roller wear is borderline — rollers that still pass visual inspection but have reduced friction — paper condition changes can trigger the first 20-01 events before the rollers themselves are replaced.

  1. Identify the paper stock currently loaded in the source tray that produced 20-01. Verify the paper weight is within the machine’s specified range — typically 60–90 g/m² for standard transport. Very heavy paper (above 120 g/m²) creates substantially higher transport resistance against VT section guides and requires full-specification roller nip force to transport reliably. Marginal VT rollers that feed standard paper reliably may produce 20-01 on heavy stock
  2. Check the paper for moisture absorption — paper that has been exposed to high humidity has increased surface friction against guide plates and reduced sheet stiffness. Test by running the same job from fresh paper from a sealed ream. If 20-01 clears with fresh paper but recurs with the stored paper stock, paper humidity is a contributing factor. This does not eliminate the need to inspect VT rollers — moisture-related 20-01 typically indicates rollers that are borderline and need replacement regardless
  3. Fan the paper stack before reloading — particularly for lower tray sources where the paper stack is tall. A fanned stack reduces inter-sheet static bonding that can cause multiple sheets to enter the VT section simultaneously. Double-sheet transport overloads the roller nips and produces a distinctive jam pattern (two sheets found together, folded at the VT nip entry)
  4. Run a 20-sheet test from the affected source after reloading with confirmed-specification fresh paper. If 20-01 does not recur, document the paper stock as a contributing cause and advise the customer on correct paper storage and specification. If 20-01 recurs with fresh specification paper, the fault is mechanical and the investigation continues at Step 4

Step 4 — Inspect VT Section Transport Rollers and Nip Pressure

The VT section transport rollers are the highest-probability mechanical component for gradual-onset 20-01. Inspection requires accessing each roller pair in the vertical transport section, evaluating both the driven roller surface condition and the pinch roller nip pressure. On machines with extended lower cassette configurations, the VT section may contain five or more roller pairs — each must be inspected individually.

  1. With the machine powered off and main power cord disconnected, open all right-side access panels providing access to the vertical transport section. Consult the model-specific service manual to identify the full extent of the VT section and all roller pair locations — on PFTDB platform models, the VT section extends through the PFTDB unit as well as the base machine, and additional roller pairs may require access from the lower unit’s transport panel
  2. Systematically inspect each VT driven roller (the rubber-coated roller driven by the motor) visible in the transport section:
    • Surface condition: The driven roller surface should be matte, slightly textured, and slightly resilient when pressed with a finger. A glazed roller surface appears shiny and smooth, and feels hard with no give. Early glazing produces a faint sheen — visually subtle but sufficient to reduce transport friction below the threshold for reliable transport under load. Replace any driven roller with visible glazing, regardless of how minor the glaze appears. On intermittent 20-01 calls, a “just barely glazed” roller is the cause — replace it
    • Paper dust contamination: Black paper dust embedded in the roller surface or accumulated in the rubber grooves reduces effective grip. Clean contaminated rollers with a lint-free cloth lightly dampened with water. Dry completely before testing — a damp roller surface has temporarily increased friction that will return to the degraded state once dry. If cleaning does not restore a matte, slightly tacky surface, the roller is glazed beneath the contamination layer and must be replaced
    • Surface damage: Cuts, flat spots from a seized roller, or torn rubber from contact with a foreign object. Any surface damage requires roller replacement — damaged rollers produce periodic transport irregularities that worsen over time
    • Shaft concentricity: Spin each driven roller by hand. The roller should spin smoothly with consistent radius throughout its rotation. A roller with a bent shaft or a damaged core oscillates as it rotates — the high point of the oscillation reduces nip force intermittently, causing transport speed variation that can result in 20-01 on heavy paper or at elevated temperatures
  3. Inspect each pinch roller (the spring-loaded idler roller pressed against the driven roller) and its spring assembly:
    • Push each pinch roller away from its driven roller by hand and release — it should return promptly and firmly to the nip position. A pinch roller that returns slowly or with visible looseness in the spring mount has a fatigued spring. Reduced spring force translates directly to reduced nip pressure and transport force — a progressively weakening pinch roller spring produces gradual-onset 20-01 identical to driven roller glazing
    • Confirm each pinch roller spins freely on its shaft. A pinch roller that is seized — does not spin when the driven roller is rotated by hand — acts as a brake rather than a guide, creating additional transport resistance that can stop paper in the VT section
    • Check that pinch roller mounting brackets are not bent, cracked, or displaced. A bent bracket positions the pinch roller at an angle relative to the driven roller, concentrating nip force at one end and reducing it at the other — producing one-sided paper transport that causes skewed feeds and intermittent 20-01
  4. Specifically inspect the VT roller nips for lodged paper fragments or foreign objects. Insert a flashlight beam into the nip from the side and inspect the full width of the nip for any obstruction. A fragment as narrow as 5–8mm can cause consistent 20-01 without being visible from a straight-on view of the transport section — the side-angle flashlight inspection is essential. Use a pair of non-metallic tweezers or a cotton swab to extract any fragment found in a nip — do not use metallic tools near sensor windows or circuit board areas
  5. After completing the roller inspection, clean all roller surfaces with a lint-free cloth (water only — no solvents on rubber). Replace all driven rollers showing glazing or surface damage. Replace any pinch roller with a fatigued spring at the same time
  6. After roller replacement or cleaning, reconnect power and run a 30-sheet test from each paper source that was producing 20-01. Confirm 20-01 does not recur at any source before proceeding to motor or sensor investigation

Step 5 — Verify VT Motor Operation, Timing Belt, and Drive Gear Train

When 20-01 fires simultaneously from all paper sources and the VT roller nips have been confirmed clear of obstructions and the roller surfaces are in good condition, the VT motor or its drive train has failed. A failed VT motor or timing belt stops all transport rollers simultaneously — no source can feed paper through the VT section. This is a complete transport failure, as distinct from partial transport failures produced by individual roller or guide failures.

  1. Enter Service Mode and navigate to the State Confirmation (sometimes labeled as I/O Check or Sensor/Load Check) for the model. Command the VT motor (M1 on MFPB/BASEB platform; M22 on PFTDB platform) to run:
    • Listen for motor operation — a running M1 or M22 produces a smooth, consistent hum. Absence of any sound with a confirmed I/O command indicates motor failure (motor coil open circuit) or motor drive circuit failure on the engine board
    • With the right-side transport access panel open (and appropriate safety precautions taken — ensure no one’s hands are in the transport section), confirm that the main transport shaft rotates when M1 is commanded. If the shaft rotates but VT rollers downstream do not rotate, the timing belt between M1 and the main shaft has slipped or broken
    • On PFTDB models, separately command M22 (lower VT section motor). M22 failure produces 20-01 from lower tray sources with upper section (Tray 1 / Tray 2) potentially still functional
  2. Inspect the timing belt from M1 (and M22 on PFTDB models) to the main transport drive shaft:
    • A broken timing belt is immediately obvious — the belt is in pieces or completely absent from its pulleys
    • A slipped timing belt (still intact but off one pulley) produces the same complete transport failure as a broken belt. Check both pulleys for belt engagement
    • A stretched timing belt with reduced tooth engagement produces intermittent transport slip under load — paper starts to transport but decelerates when the belt skips a tooth under the load of transporting heavy paper. This produces 20-01 specifically on heavy paper stock while lighter paper transports normally
    • Inspect the belt surface for cracks along the tooth valleys — cracking is an early indicator of belt aging that precedes breaking. Proactive belt replacement when cracking is found prevents unscheduled 20-01 downtime
  3. Inspect the VT drive gear train — the series of gears transmitting motion from the main drive shaft to individual VT roller shafts:
    • Rotate the main drive shaft by hand and observe all VT roller pairs for smooth, simultaneous rotation. Any VT roller pair that does not rotate when the main shaft is turned indicates a broken or seized gear in the drive path to that roller
    • Listen for clicking, grinding, or irregular rotation while turning the drive shaft by hand — a broken gear tooth produces a click once per gear revolution as the gap passes the mesh point
    • Inspect accessible gears visually for broken teeth, cracked hubs, or worn tooth profiles. Gears with broken teeth must be replaced — a broken tooth creates a periodic transport failure and will eventually cause the adjacent gear teeth to chip from repeated impact at the gap
    • Check gear-to-shaft engagement — a gear that rotates freely on its shaft (hub-to-shaft engagement failure) does not transmit drive to the downstream rollers despite the main shaft rotating correctly. Test by marking the gear and its shaft with a paint pen and rotating the shaft — if the mark on the gear does not move with the shaft mark, the gear is freewheeling on the shaft
  4. If M1 failure is confirmed (motor does not run on direct I/O command, confirmed power supply to the motor connector, confirmed motor harness continuity):
    • Reseat the M1 motor harness connector at the engine board before replacing M1 — a loose connector at the board can produce the same no-rotation result as a failed motor
    • Replace M1 per the model-specific service manual. M1 replacement on most bizhub models requires removing the main drive assembly, which also carries the timing belt, the main transport clutch, and on some models the registration clutch. Follow the exact reassembly sequence in the service manual — incorrect reassembly of the main drive assembly produces multiple transport failures across all sections simultaneously
    • After M1 replacement and main drive reassembly, run a 50-sheet test from each paper source before returning the machine to service — M1 drives not only the VT section but also the registration roller and fuser transport, and all three sections must be confirmed functional after replacement
  5. If M1 is confirmed operational but VT roller nips are not rotating (timing belt or gear failure):
    • Replace the timing belt per the service manual, noting the belt routing and tension specification. Over-tensioned timing belts increase motor load and accelerate motor bearing wear; under-tensioned belts slip under load. Set belt tension to the specification in the service manual using the specified tension gauge or deflection test method
    • Replace failed gears per the service manual. On machines where the drive gear train is an accessible gear cluster on the right-side drive assembly, individual gear replacement is straightforward. On machines where the gear train is embedded in the main drive assembly, full assembly replacement may be more practical than individual gear replacement

Step 6 — Inspect VT Section Guide Plates and Clear the Transport Path

VT section guide plates define the paper’s travel direction through the vertical transport path. A displaced, bent, or missing guide plate creates a paper catch point that stops transport for every sheet that reaches that point, regardless of roller and motor condition. Guide plate displacement is most commonly caused by forceful paper removal during a jam clearing event.

  1. With all VT section access panels open, systematically inspect every guide plate in the vertical transport section — both the stationary guide plates on the fixed machine structure and any movable guide plates on hinged or removable access panels. Use a flashlight to illuminate the full depth of each guide’s paper-facing surface
  2. Verify each guide plate is correctly seated:
    • Each guide plate should sit flush in its mounting position with no step, gap, or raised edge along any paper-facing surface. A guide plate displaced from its mounting tab presents a raised edge perpendicular to the paper travel direction — the paper leading edge catches on this edge and folds
    • Each guide plate’s mounting tabs (typically plastic tabs that click into slots in the guide housing) should be fully engaged. A guide plate with one tab disengaged will appear nearly flat but will have a slight angle relative to adjacent guides — enough to catch a paper leading edge
    • Inspect guide plates for cracks — a cracked guide plate may appear correctly seated but will flex under paper contact, momentarily presenting a sharp edge into the paper path
  3. Pay specific attention to the guide plates at each tray-to-VT junction — the transition points where paper exits a source tray’s feed section and enters the shared VT path. These junction guide plates are the most mechanically stressed in the paper path (they redirect the paper from horizontal or angled to vertical travel) and are the most commonly displaced during jam clearing. A guide plate dislodged at the Tray 2-to-VT junction produces 20-01 specifically from Tray 2 while all other sources function normally — a source-specific 20-01 pattern that points directly to the junction guide for that tray
  4. Inspect the guide surfaces for accumulated paper debris — paper coating residue, toner particles, or paper dust deposited on guide surfaces increases friction between the paper and the guide, reducing transport velocity. Clean guide surfaces with a dry or lightly dampened lint-free cloth. Do not use abrasive materials on guide plate surfaces — scratches on guide surfaces create additional paper friction points
  5. On models with a mylar or plastic film guide in the VT section (thin flexible guide material used to deflect paper from the VT path toward the registration area), inspect the film guide for tears, creases, or detachment from its mounting. A torn or detached mylar guide either creates a paper deflection point (paper folds against the tear edge) or fails to deflect the paper correctly toward the registration area, sending it into the machine structure instead
  6. After confirming all guide plates are correctly seated and surfaces are clean, run a test print from the source that produced 20-01. Observe the paper’s path through any open access panel if possible — a guide plate that appears correctly seated in static inspection may reveal its misalignment as the paper passes through

Step 7 — Verify VT Intermediate Sensors and Registration Sensor in Service Mode

When the paper stop position in Step 1 showed paper at or near the registration area, or when no paper is found in the VT section despite 20-01 being logged, the VT intermediate sensor or registration sensor has failed to detect paper that successfully transported through the section. Sensor verification in Service Mode confirms or excludes sensor failure without requiring component replacement.

  1. Enter Service Mode and navigate to the I/O check section for the model. Identify the VT intermediate sensor(s) and the registration sensor from the component reference table above
  2. Verify each VT intermediate sensor (PS38 / PS39 / PS40 on PFTDB models; PS_VT on applicable MFPB models):
    • With no paper in the sensor path, the sensor should show OFF (no paper detected)
    • Insert a piece of paper into the sensor aperture — the sensor should immediately show ON. Remove the paper — it should return to OFF
    • A sensor that shows constant OFF regardless of paper in the aperture: clean the sensor window with a dry lint-free cloth (paper dust is the most common cause), reseat the sensor harness connector, and retest. If constant OFF persists after cleaning and connector reseating, replace the sensor. A sensor permanently in the OFF state produces 20-01 on every print from any source routed through that sensor’s position — the paper transports correctly but is never detected
    • A sensor that shows constant ON (paper present signal with the path clear): the sensor actuator may be jammed in the triggered position, or the sensor has failed internally. Inspect the sensor aperture for a jammed actuator flag. If no physical jam is present, replace the sensor. A sensor stuck ON causes the engine board to believe paper is always in the VT section, which prevents subsequent feeds from being initiated and may produce fault codes related to paper presence rather than 20-01
  3. Verify the registration sensor (PS1 / PS9 / PS4 depending on model):
    • The registration sensor is the final detection point in the VT section and serves dual duty — it detects paper arrival in the VT section timing context (for 20-01) and serves as the paper-present signal for the registration clutch timing (for -02 loop forming codes). A failed registration sensor therefore produces both 20-01 (paper arrives but is not detected) and potential -02 codes (registration clutch timing is lost)
    • Apply the same test procedure: OFF with clear path, ON when paper is inserted, immediate return to OFF when paper is withdrawn
    • Clean the registration sensor window — paper dust and toner contamination on the registration sensor window is significantly more common than on intermediate VT sensors because the registration sensor is located at the junction between the paper transport and the imaging section, where both paper and toner are present
  4. After sensor cleaning and verification, run a 20-sheet test from the affected paper source. If 20-01 clears after sensor cleaning, document the cleaning in the service log and add sensor window cleaning to the PM checklist for the machine — a machine that produced 20-01 from sensor contamination is operating in an environment or on paper stock that deposits unusual contamination on sensor windows, and will require more frequent sensor cleaning at PM visits

Step 8 — Component Replacement Sequence

When all preceding inspection and testing steps have been completed and 20-01 persists, component replacement follows the sequence established by the stop position and fault pattern analysis. The sequence below reflects the diagnostic logic — do not skip to board replacement without completing all mechanical inspection steps first. Board failure is the rarest cause of 20-01, and every board replacement on a 20-01 call that was caused by a paper fragment or glazed roller is a preventable parts cost and a diagnostic failure.

  • Replace all glazed or damaged VT driven rollers and their paired pinch rollers: When VT roller inspection in Step 4 identified glazed roller surfaces, replace the affected roller pairs as matched sets. Do not replace only the driven roller without also checking the pinch roller spring — a new driven roller paired with a fatigued pinch roller spring immediately produces 20-01 on heavy paper. On machines above 500k copies where multiple VT rollers show early-to-moderate glazing, replace all VT driven rollers in the section as a set rather than individually — staggered roller wear will produce a return 20-01 call from the next-worst roller within weeks of the first replacement
  • Replace the VT timing belt when belt wear is confirmed: Timing belt replacement requires accessing the motor and main drive shaft assembly. Follow the service manual procedure for belt routing, pulley seating, and tension specification precisely — an incorrectly tensioned timing belt produces motor overload (over-tension) or belt slippage under load (under-tension). After belt replacement, run the motor in Service Mode at rated speed and listen for belt noise (squealing from over-tension; slipping from under-tension) before loading paper
  • Replace failed VT drive gears: When a broken or seized gear is identified in Step 5, replace the specific gear per the service manual parts list. Confirm the replacement gear part number matches exactly — gear modules and tooth count must be correct for the gear to mesh properly with adjacent gears. After replacement, turn the drive train by hand through several rotations and confirm smooth, click-free rotation from all roller pairs before reconnecting power
  • Replace M1 (main transport motor) — MFPB/BASEB platform: When M1 is confirmed failed by I/O command testing in Step 5, replace M1 per the service manual. Note that M1 replacement involves the main drive assembly and must be followed by a complete transport system test covering VT section, registration roller, and fuser entry transport — all three sections are driven by M1 and all must be verified after replacement. Check the motor drive circuit on the engine board (MFPB / BASEB) for burn marks or damaged transistors before installing the new motor — a failed motor drive circuit will destroy a new motor in the same failure mode
  • Replace M22 (lower VT section motor) — PFTDB platform: When M22 is confirmed failed on PFTDB platform models, replace M22 per the PFTDB or base machine service manual. M22 on PFTDB models specifically drives the lower vertical transport section — confirm M1 operation is unaffected after M22 replacement. After M22 replacement, verify all lower tray sources (Tray 2, 3, 4) produce 20-01–free feeds before considering the repair complete
  • Replace VT intermediate sensors or registration sensor: When sensor failure is confirmed in Step 7 (sensor does not respond to paper insertion after cleaning and harness reseating), replace the failed sensor per the service manual. After replacement, verify the new sensor toggles correctly in Service Mode before running a test print. For registration sensor replacement specifically, run the color registration auto-adjust procedure in Service Mode on color models — the registration sensor position affects color alignment calibration on some platforms
  • Replace engine board (MFPB / BASEB / FRB / PFTDB) — last resort only: Engine board failure as a cause of 20-01 is rare and occurs only when the motor drive circuit on the board fails — not when 20-01 is caused by a mechanical paper transport failure. An engine board should only be replaced for 20-01 if: M1 does not run on I/O command despite confirmed motor harness continuity and confirmed motor coil continuity (motor is functional but board is not energizing it); or a VT sensor shows incorrect state in Service Mode despite confirmed sensor functionality (board input circuit failure). In either case, follow the board replacement sequence appropriate to the model platform, complete all board initialization procedures, and verify all transport sections before returning to service

Quick Reference — Troubleshooting by Symptom

SymptomMost Likely CauseFirst Action
20-01 appeared immediately after clearing a previous jam; fires on every print from every sourcePaper fragment torn during jam clearing is lodged in a VT roller nip — most common cause of sudden-onset consistent 20-01Inspect every VT roller nip with a flashlight, especially nips at and immediately downstream of the previous jam location; remove fragment with non-metallic tweezers; run 10-page test from each source before closing any panel
20-01 from all sources; concurrent jam codes in registration area or fuser exit section on the same print attemptVT motor (M1) failure or timing belt failure — all transport sections share M1 drive; simultaneous multi-section failures confirm shared motor causeCommand M1 in Service Mode I/O check; listen for motor; confirm main transport shaft rotation; inspect timing belt for breakage or pullout; replace belt first (lower cost), then M1 if shaft does not rotate on confirmed motor operation
20-01 from all sources; no other section jam codes; VT rollers confirmed clear of obstructionsVT drive gear broken tooth or seized gear stopping all downstream VT rollers; or VT timing belt slippage under loadTurn main drive shaft by hand; listen for clicking (broken tooth) or feel for binding (seized gear); inspect timing belt tension and tooth engagement; replace broken/seized gear or retension/replace belt
20-01 only from Tray 3 and Tray 4 (lower sources); Tray 1 and Tray 2 print normallyFault in the lower VT section that carries paper from lower sources — lower VT roller nip obstruction, lower VT roller glazing, or lower VT drive issue; Tray 1/2 shorter path bypasses the faulty zoneInspect VT roller nips in the lower VT section (the transport section between the Tray 3/4 exit area and the mid-VT merge point with Tray 1/2 path); inspect M22 on PFTDB platform models with dedicated lower VT motor
20-01 only from Tray 2 (one specific source); other sources print normallyGuide plate at Tray 2-to-VT junction displaced, or VT intermediate sensor specific to Tray 2 path (PS38 on PFTDB) failed or contaminatedInspect transition guide plate at Tray 2 exit-to-VT junction for displacement; verify PS38 (PFTDB) or Tray 2 VT sensor state in Service Mode; clean sensor window; replace sensor if stuck OFF after cleaning
20-01 intermittent — 1 in 30–100 sheets, escalating over weeks; affects all sources equallyVT driven roller progressive glazing — the dominant cause of gradual-onset 20-01 on high-copy machinesInspect all VT driven roller surfaces for early glazing (faint sheen, slight hardness); check VT copy counter against roller PM interval; replace all glazed rollers and paired pinch rollers as matched sets
20-01 with paper found at registration area; paper appears to have transported correctly; 20-01 not -02VT intermediate sensor or registration sensor contaminated or failed — paper transported correctly but was not detected by the sensor within the VT timing windowClean registration sensor window (PS1/PS9/PS4) and all VT intermediate sensor windows; verify each sensor toggles correctly in Service Mode I/O check when paper is inserted; replace any sensor that remains stuck OFF after cleaning
20-01 on heavy paper or coated stock only; standard paper feeds without error from the same sourceVT driven rollers borderline glazed — sufficient friction for standard paper but insufficient for the additional transport resistance of heavy or coated stockInspect VT driven roller surfaces carefully — early glazing that is visually subtle can still reduce transport force enough to fail on heavy paper; replace rollers even if glazing appears minor; also verify timing belt tension is not low
20-01 appearing at a regular periodic rate — every Nth page regardless of sourceVT drive gear broken tooth — periodic transport failure as broken tooth gap passes the mesh point once per gear revolutionListen during transport for periodic clicking at the same interval as the 20-01 occurrence frequency; turn drive train by hand and identify the clicking gear; inspect accessible gears for broken teeth; replace affected gear
20-01 with paper found sharply folded at a specific point in VT section; fold is clean and angular (not crumpled)Guide plate displaced at the fold point — paper leading edge caught on guide plate edge and folded against it; paper transported at full speed into the stationary obstructionLocate the guide plate at the fold point; confirm mounting tabs are engaged; reseat displaced guide plate; inspect for cracks; check guide plate at that position specifically and all surrounding plates for secondary displacement
20-01 appearing after machine was moved or transport section covers were removed for unrelated serviceGuide plate dislodged during transport or during cover removal — a guide that was correctly seated was displaced by vibration or by contact during a cover removalSystematically inspect all guide plates in the VT section, paying particular attention to guide plates adjacent to the access covers that were removed; reseat any guide with a disengaged mounting tab; confirm all covers are reinstalled in the correct sequence before testing
20-01 persists after clearing all VT roller nips, replacing all VT rollers, and verifying all sensorsVT motor drive circuit failure on engine board — motor does not respond to confirmed I/O command despite confirmed motor and harness continuityMeasure motor coil resistance at harness connector (compare to SM specification); measure voltage at motor connector during I/O command; if voltage is absent despite confirmed board power, the motor drive transistor on MFPB/BASEB/PFTDB has failed; replace the board after confirming all mechanical causes are excluded

Understanding the 20-xx Vertical Transport Section Jam Code Family

Jam Code 20-01 belongs to the 20-xx code family — the complete set of fault codes originating in the shared vertical transport section between source tray exits and the registration area. Reading the suffix digit correctly identifies the failure stage and the diagnostic approach before any panel is opened:

  • 20-01 — VT section primary misfeed — paper successfully left the source tray but was not detected at the VT section sensor or registration sensor within the timing window. Mechanical paper transport failure in the shared VT section — rollers, motor, drive train, guide plates, or VT sensors. The source tray feed mechanism is confirmed functional. Affects all sources or specific sources depending on which VT zone has failed. This article
  • 20-02 — VT section late arrival at registration — paper traversed the full VT section but arrived at the registration nip too late for correct loop forming before the registration clutch fired. Marginal mechanical timing failure — the paper moved through the VT section but not at the required speed. Paper found buckled or crumpled at the registration nip rather than stalled in the VT section. Investigate worn VT transport rollers reducing transport velocity (not fully stopping paper — the Category 2 glazing in this article that has not yet progressed to full stop), misaligned guide plates increasing transport resistance without stopping the paper, or incorrect registration loop timing in Service Mode. 20-02 and 20-01 share root causes (VT roller wear is the dominant cause of both) but represent different severity levels: 20-02 is the earlier-stage manifestation of the same roller degradation that eventually produces 20-01
  • 20-40 — VT section image write signal timeout — paper successfully traversed the VT section and reached the registration sensor on time, but the WTEN authorization signal was not issued within the timeout window. Board-level synchronization failure — not a mechanical fault in the VT section. Diagnose identically to 11-40, 12-40, 13-40, and 14-40: investigate controller–engine board communication, firmware version matching, HDD/SSD delivery path, and imaging section ready state. The VT section mechanical transport is confirmed functional by paper arrival at the registration sensor

The -01 / -02 / -40 suffix logic applies completely consistently across the 20-xx code family — the same three mechanical stages (no movement, slow movement, correct movement but imaging authorization failure) that apply in every tray-source code family also apply in the shared VT section family. The key distinction of the 20-xx family is that it addresses the shared infrastructure rather than any individual tray source: a fault in the 20-xx zone affects all sources simultaneously when it is in the shared path, rather than being isolated to a single tray as with 11-xx, 12-xx, 13-xx, or 14-xx codes.

Preventing Jam Code 20-01 From Recurring

  • Adopt a two-phase jam clearing protocol — clear and inspect, never clear and close. The dominant cause of sudden-onset consistent 20-01 is a paper fragment left in the VT section from a previous jam clearing event. The most effective prevention is a mandatory inspection of all VT roller nips after every jam clearing event before the access panels are closed. This takes 60 seconds with a flashlight. It eliminates Category 1 (fragment obstruction) as a recurring cause entirely — a cause that accounts for the majority of 20-01 calls that technicians receive as callbacks following a customer-performed jam clearing. Train customer key operators to perform this inspection as part of the jam clearing procedure, and laminate a reminder card on the right-side access panel
  • Include VT section roller inspection and cleaning at every PM visit. VT transport rollers are not always included in standard bizhub PM parts kits because their service life is longer than source tray feed rollers. However, at the PM visit interval, roller surfaces should be inspected and cleaned regardless of whether replacement is due. Early-stage glazing identified and cleaned at PM prevents the progressive degradation that produces 20-01 in the weeks following a PM visit. A machine that leaves a PM visit with clean, confirmed-serviceable VT rollers will not produce glazing-related 20-01 until the next PM cycle at the earliest
  • Replace VT transport rollers proactively at the machine PM interval on high-duty-cycle machines. On machines where copy volume is near or above the machine’s rated duty cycle, VT roller wear accumulates at the maximum rated rate. Rather than waiting for 20-01 to appear, schedule VT roller replacement at every PM cycle on machines above 80% rated duty cycle. The incremental PM parts cost is consistently less than the callback cost for a 20-01 service call. Document VT roller replacement in the machine service log with the total copy counter value at replacement, so the next technician can immediately assess roller age on any 20-01 call
  • Inspect VT section guide plates whenever any transport section cover is removed for any purpose. Guide plate displacement from transport cover removal is a preventable cause of 20-01 that appears immediately after a service visit and produces the frustrating pattern of 20-01 following a PM or unrelated repair. Incorporating a guide plate confirmation check (all tabs engaged, all surfaces flush, all edges smooth) into the standard close-out procedure for any transport section access prevents this category of post-service 20-01
  • Check and record VT drive timing belt condition at every major PM on machines above 400k copies. Timing belt aging is a slow progression — belts do not fail suddenly from a healthy state. The crack-tooth-failure progression (surface cracks → tooth root cracks → tooth loss → belt failure) takes thousands of copies to develop. A technician who inspects and documents timing belt condition at each PM — noting the presence of surface cracking, tooth wear, or edge fraying — can predict belt replacement need 1–2 PM cycles before failure, scheduling proactive replacement during a planned PM rather than as an emergency replacement during a 20-01 outage call
  • Clean all VT section sensor windows at every PM, not just the sensors directly associated with reported jam codes. VT intermediate sensor contamination produces 20-01 that appears entirely random — no pattern based on paper source, job complexity, or time of day — because the sensor fails to detect paper on some passes but detects it on others as the contamination level fluctuates with humidity and airflow. Including a systematic sensor window cleaning in the PM procedure prevents this from reaching the level of consistent failure. A 2-minute sensor cleaning investment at PM prevents a callback call

Professional Technician Summary

Jam Code 20-01 is the vertical transport section primary misfeed — a mechanical paper transport failure in the shared paper highway that all tray sources use to deliver paper to the registration area. The source tray mechanical feed is confirmed functional by the time 20-01 fires. All diagnostic effort must be directed at the vertical transport section itself: its rollers, its motor and drive train, its guide plates, and its sensors.

The first and most important diagnostic action on every 20-01 call is establishing the fault scope: does 20-01 fire from all paper sources or only from specific sources? All sources failing simultaneously means the fault is in the shared infrastructure — motor, timing belt, main drive gear, or an obstruction in the upper shared VT path. A specific tray source failing while others print normally means the fault is in the VT path segment specific to that source — a lower VT roller section, a tray-to-VT junction guide plate, or a per-tray VT intermediate sensor. This single determination eliminates half the VT section from investigation immediately.

In the field, 20-01 resolves to one of three dominant causes on the overwhelming majority of calls:

A paper fragment in a VT roller nip — the most common cause of sudden-onset consistent 20-01 and the most easily prevented. It appears immediately after a jam clearing event. It is confirmed by flashlight inspection of VT roller nips. It is resolved in under two minutes with non-metallic tweezers. It never requires parts replacement. Every technician arriving on a 20-01 call that appeared after a customer-performed jam clearing should inspect all VT roller nips before opening any other diagnostic track.

Progressive VT driven roller glazing — the most common cause of gradual-onset intermittent 20-01 on high-copy machines. It shows as a shiny or hard roller surface that has lost its matte grip texture. It begins at 1 in 100 feeds and escalates to consistent failure over weeks. On machines above 500k copies, a 20-01 call with an escalating intermittent history has a glazed VT roller as the cause in the majority of cases before any other cause is reached. Replace all VT rollers showing any stage of glazing, always as matched driven-roller-plus-pinch-roller sets.

VT motor or timing belt failure — identified immediately by 20-01 appearing from all sources simultaneously, often accompanied by concurrent jam codes in the registration area and fuser exit section that share the M1 drive. The multi-section simultaneous failure pattern is the exclusive diagnostic signature of motor or belt failure and directs the repair to the motor check in Service Mode as the first active diagnostic step.

Do not replace engine boards for 20-01. Board failure as a primary cause of mechanical transport failure is rare, and every board replaced on a 20-01 call that was actually caused by a paper fragment, a glazed roller, or a belt is a preventable cost. Complete all mechanical inspection steps — roller surfaces, drive train, guide plates, sensors — before engine board replacement is considered. The mechanical causes of 20-01 are invariably faster to resolve, less expensive, and more reliably confirmed than board-level causes.

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