Jam Code 15-01 is a Large Capacity Tray (LCT) feed section primary misfeed on Konica Minolta bizhub machines. On the model platforms where this designation applies, the LCT occupies the fifth paper source position in the machine’s tray enumeration — following the standard Tray 1 through Tray 4 designations — and its jam codes are accordingly numbered in the 15-xx range rather than the 16-xx range used on other bizhub platforms for the equivalent physical unit. The underlying hardware, the elevator mechanism, the feed roller and separation roller assembly, and the diagnostic approach are functionally identical regardless of which code number the operator panel displays — the difference is purely a matter of how a given model platform enumerates its paper sources, not a difference in the LCT hardware itself. A technician moving between different bizhub model families should expect to see this same fault reported as 15-01 on some platforms and as 16-01 on others, and should apply the same diagnostic logic in either case.
Konica Minolta service documentation describes this code under the heading Misfeed at LCT Paper Feed Section — deliberately scoped to the feed section specifically, distinct from the broader vertical transport path that carries paper onward from the LCT toward the base machine. The -01 suffix carries the standard mechanical meaning established throughout this series: paper failed to reach the LCT feed sensor within the specified timing window after the LCT feed clutch or feed motor was energized following elevator height confirmation. This is a genuine mechanical misfeed — the paper did not leave the LCT cassette and enter the transport path at all.
The official Konica Minolta description states precisely:
Paper fed from the LCT did not reach the LCT feed sensor within the specified time after the LCT feed clutch or feed motor was energized, following confirmation of correct elevator position at the upper limit sensor.
Translated into field language: before every feed cycle, the LCT controller confirms the paper stack is correctly positioned at feed height via the upper limit sensor, then energizes the feed clutch or feed motor to drive the pickup roller against the top sheet of the stack. Within the timing window that follows, the LCT feed sensor — positioned immediately downstream of the cassette exit nip — must detect the paper’s leading edge. If it does not, the LCT feed section has failed to move the top sheet out of the cassette and into the transport path at all. The machine recorded 15-01.
This article scopes its diagnostic focus specifically to the LCT feed section: the elevator, the pickup roller, the separation mechanism, and the LCT feed sensor itself — the zone between the paper stack and the point where paper exits the cassette nip. On the model platforms using the 15-xx enumeration, faults occurring further downstream — in the LCT’s internal vertical transport section, at the LCT-to-base-machine junction, or in board-level WTEN timing — are covered under separate, distinct jam codes specific to those zones, exactly as the 16-xx family on other platforms separates feed-section faults (16-01) from board-level faults (16-40). The diagnostic principles, component functions, and root cause categories for the LCT feed section itself are identical across both numbering schemes, because the physical hardware performing this function — the elevator-driven paper stack, the pickup roller, and the separation mechanism — does not vary by how the platform’s firmware happens to number it.
| Field | Details |
|---|---|
| Jam Code | 15-01 (LCT enumerated as Tray 5 on applicable platforms; functionally equivalent to 16-01 on platforms using the 16-xx LCT numbering) |
| KM Category Heading | Misfeed at LCT Paper Feed Section — scoped specifically to the feed section: the elevator-driven paper stack, the pickup roller, the separation mechanism, and the LCT feed sensor. The -01 suffix means paper failed to reach the LCT feed sensor within the timing window after the feed clutch/motor was energized — the paper never successfully exited the LCT cassette |
| Critical distinction from LCT vertical transport or board-level codes | 15-01 means paper never left the LCT cassette nip at all — a feed-section mechanical failure. This is distinct from any code addressing paper that exited the cassette successfully but stalled further into the LCT’s internal transport path, and distinct from any WTEN-style board-level timeout where paper reached the registration sensor but was held awaiting imaging-section authorization. Do not apply board-level or firmware diagnostics to 15-01 — it is exclusively a feed-section mechanical fault |
| Platform numbering note | Whether a given bizhub model displays this fault as 15-01 or 16-01 depends entirely on that platform’s paper source enumeration scheme — some model families count the LCT as the fifth tray position (15-xx), others as a sixth or separate designation (16-xx). Always confirm the exact code displayed on the operator panel against the model-specific SM’s jam code reference table, but proceed with the identical feed-section diagnostic approach regardless of which number is shown, since the physical hardware and failure modes are the same |
| Detection Logic — All applicable platforms: | After the LCT feed clutch (CL_LCT / CL1 in LCT unit) or LCT feed motor was energized, following elevator confirmation at the upper limit sensor (PS_HL), paper was not detected at the LCT feed sensor (PS_F / PS1-LCT) within the specified timing count. The detection logic, timing structure, and controlling sequence are identical to the LCT feed detection logic documented for 16-01 on other platforms |
| LCT Elevator Logic: | Identical in function to the elevator system documented for 16-01: the LCT maintains the paper stack top at the feed roller nip via an elevator motor that raises the paper platform, controlled by feedback from the upper limit sensor. As sheets are consumed, the elevator rises incrementally to maintain constant feed height and constant feed force regardless of remaining stack quantity |
| Key Components | LCT controller board (LCTB / LCDB); elevator motor (M_E / M1-LCT); elevator drive belt and gear assembly; upper limit sensor / stack height sensor (PS_HL / PS_H); lower limit sensor (PS_LL — where fitted); paper empty sensor (PS_PE / PS_E); LCT feed (pickup) roller; LCT separation roller or separation pad; LCT feed clutch (CL_F / CL1-LCT) or LCT feed motor; LCT feed sensor (PS_F / PS1-LCT — the sensor whose failure to trigger defines 15-01); LCTB-to-primary-engine-board communication harness. All components and their functions are identical to those documented for the 16-01 LCT feed mechanism |
| Severity | High — LCT disabled for print; typically escalates from intermittent to consistent over weeks as feed rollers progressively glaze, exactly as documented for 16-01; high-volume production environments where the LCT is the primary paper source experience maximum impact |
| Related Jam Codes | 15-02 (LCT registration loop forming failure — paper fed from LCT but arrived late at registration), any LCT-specific vertical-transport or board-level codes applicable to the platform’s numbering scheme, 16-01 / 16-02 / 16-40 (the functionally equivalent code family on platforms using 16-xx LCT enumeration — refer to that article for supplementary detail on shared LCT hardware, including the elevator system and roller replacement procedures, all of which apply identically here), 11-01 / 12-01 (standard cassette tray misfeeds, for comparison to the elevator-based LCT mechanism) |
Component References
Because 15-01 applies to the identical class of LCT hardware documented for 16-01 — differing only in how the specific model platform enumerates the tray position — the component designations, elevator logic, feed roller specifications, and Service Mode check codes follow the same functional naming conventions established in that article. As with 16-01, exact PS designations, connector references, and check codes are LCT-unit-specific (PF-series) rather than being determined by the base machine platform alone, and must be confirmed in the applicable LCT unit service manual. The base machine service manual documents the LCTB-to-engine-board communication path and the Service Mode LCT sub-device status display; the LCT unit service manual documents every component inside the LCT cabinet — the elevator motor, feed roller, separation mechanism, and sensors. Both manuals are required for complete 15-01 diagnosis, exactly as both are required for 16-01.
| Component | Designation | Function | Reference |
|---|---|---|---|
| LCT controller board | LCTB / LCDB | Manages elevator positioning, feed clutch/motor timing, and sensor monitoring for the LCT unit; communicates paper status to the primary engine board | LCT unit SM |
| Elevator motor | M_E / M1-LCT | Raises the paper platform to maintain correct feed height as the upper limit sensor commands | LCT unit SM |
| Upper limit sensor | PS_HL / PS_H | Confirms paper stack top has reached correct feed roller nip height; controls elevator stop point | LCT unit SM |
| Paper empty sensor | PS_PE / PS_E | Detects paper depletion in the LCT cassette | LCT unit SM |
| LCT feed (pickup) roller | Model-specific — refer to LCT SM parts list | Contacts top of paper stack; drives top sheet toward separation roller and feed sensor | LCT unit SM |
| LCT separation roller / pad | Model-specific — refer to LCT SM parts list | Prevents multi-sheet feed by applying counter-friction to sheets beneath the top sheet | LCT unit SM |
| LCT feed clutch / feed motor | CL_F / CL1-LCT or M_F / M2-LCT | Engages to drive the pickup roller on each feed cycle | LCT unit SM |
| LCT feed sensor | PS_F / PS1-LCT | The sensor whose failure to trigger within the timing window defines 15-01; detects paper exiting the LCT cassette nip | LCT unit SM |
| LCTB-to-engine-board harness | Model-specific — refer to base machine SM | Carries feed commands and sensor status between the LCTB and the primary engine board (BASEB / MFPB / PFTDB depending on base platform) | Base machine SM |
ℹ️ This is the same LCT hardware documented in the 16-01 article — the code number is a platform enumeration difference, not a hardware difference. If your reference library includes the 16-01 service article, its full component tables (with model-specific PF-unit cross-references), its detailed elevator mechanism explanation, its seven root cause categories, and its complete eight-step diagnostic procedure apply directly to 15-01 with no modification needed beyond substituting the code number your specific machine’s panel displays. This article restates the complete diagnostic procedure in full for standalone use, but a technician already familiar with 16-01 will recognize every step, every component, and every root cause category as identical in substance.
Understanding the LCT Feed Mechanism — Why 15-01 Occurs
The LCT feed mechanism operates on the same active elevator principle documented throughout this series’ LCT coverage: rather than relying on a passive spring-loaded cassette like a standard paper tray, the LCT uses an electromechanical elevator that continuously repositions the paper platform to maintain the stack top at a constant height against the pickup roller, regardless of how much paper remains in the cassette. This is what allows the LCT to maintain consistent feed force across its full capacity — commonly 2,500 to 3,000 sheets — where a passive spring system would apply progressively less force as the stack depletes.
The complete feed sequence preceding every sheet is identical to the sequence documented for 16-01:
- Elevator position verification: The LCTB checks the upper limit sensor (PS_HL) before every feed cycle. If the sensor is not triggered — the stack has dropped below feed height — the elevator motor raises the platform until PS_HL confirms correct height, then stops
- Feed clutch/motor energization: With elevator height confirmed, the primary engine board commands the LCTB to initiate a feed. The LCTB energizes the feed clutch or feed motor, driving the pickup roller against the top sheet
- Separation and initial transport: The pickup roller drives the top sheet toward the separation roller/pad, which prevents additional sheets from being carried along
- Feed sensor detection: The paper leading edge must trigger the LCT feed sensor (PS_F) within the timing window from clutch/motor energization. Failure to trigger within this window produces 15-01
Seven root cause categories produce 15-01, in the same order of field frequency documented for 16-01, since both codes describe failures of the identical physical mechanism:
- Category 1 — LCT pickup roller worn or glazed (by far the most common cause): The pickup roller contacts the paper stack on every feed cycle across the LCT’s full capacity and duty cycle, and its rubber surface progressively glazes with accumulated cycles — hardening and losing the friction coefficient needed to reliably grip and drive the top sheet. This produces the characteristic intermittent-to-consistent escalation pattern over weeks as the surface degrades. Inspect the roller surface for a shiny, smooth contact arc versus the matte, slightly tacky texture of a new roller
- Category 2 — LCT separation roller worn or separation pad deteriorated: Reduced counter-friction allows double feeding (which jams downstream) or, in cases of severe wear, prevents the pickup roller from separating the top sheet from the stack at all. Replace together with the pickup roller as a matched set whenever either requires service
- Category 3 — LCT elevator not at correct height: Elevator motor degradation, drive belt slippage, or upper limit sensor (PS_HL) failure/contamination all prevent the paper stack from being correctly positioned at the pickup roller nip, producing insufficient or excessive feed pressure that results in unreliable pickup
- Category 4 — Paper loading errors and condition issues: Skewed loading, mixed paper sizes or weights, damaged or curled sheets, or static-charge bonding between sheets from extended storage in low-humidity conditions — all of these prevent reliable separation and pickup regardless of roller and elevator condition
- Category 5 — LCT feed sensor (PS_F) contaminated or failed: Paper feeds correctly but is not detected, producing false 15-01. Confirmed by physical inspection of the sensor window and by Service Mode verification while manually inserting paper into the sensor aperture
- Category 6 — LCT feed section transport fault immediately downstream of the pickup nip: A foreign object, guide plate displacement, or debris accumulation immediately after the cassette exit nip but before the paper would otherwise clear the feed sensor’s detection zone
- Category 7 — LCTB communication failure or feed clutch/motor failure: The LCTB does not execute the feed command, or the feed clutch/motor is not energized at all. The least common cause; confirmed by verifying LCTB communication status in Service Mode’s optional device display
Step 1 — Clear the Paper, Confirm the Stop Position, and Classify the Fault Zone
The paper stop position provides the same diagnostic value documented for 16-01 and should be established before any Service Mode check or component inspection.
- Open the LCT front access door or transport access panel as indicated by the operator panel jam indicator
- Observe and note paper location before removal — where the leading edge stopped indicates where the feed sequence failed
- Remove jammed paper carefully, pulling in the direction of paper travel
- Classify the stop position:
- No paper exits the cassette — leading edge still at or within the cassette nip, separation roller area, or less than 30mm past cassette exit: Points to Category 1 (pickup roller) or Category 3 (elevator height). This is the most common stop position in the field
- Two overlapping sheets (double feed): Points to Category 2 (separation roller/pad wear)
- Skewed leading edge: Points to Category 4 (paper loading) or worn lateral guides
- No paper found anywhere: Check whether PS_F is stuck ON in Service Mode (Category 5) before assuming a genuine feed failure occurred
- Inspect the feed area for paper fragments or dust after removal; clear with compressed air directed away from sensor windows before closing the access panel
Step 2 — Review Service History, LCT Copy Counter, and Fault Pattern
- Access the Error History log in Service Mode and review recent 15-01 events for consistency vs. intermittency, exactly as documented for 16-01: consistent failure on every feed points to a hard mechanical fault (glazed roller, elevator stuck); intermittent-escalating failure points to progressive roller glazing; failure only on first feeds after a full reload points to elevator overshoot on maximum travel; failure only at low paper level points to elevator drive wear or marginal roller pressure at minimum stack height
- Check the LCT-specific copy counter (independent from the base machine total counter) against the roller PM replacement interval specified in the LCT unit SM — typically 200,000–300,000 sheets fed through the LCT, though this varies by unit model
- Check service history for recent LCT interventions: roller replacement (verify correct part and installation), elevator service, or repeated jam-clearing events that may have deposited debris on the feed roller
Step 3 — Inspect Paper Loading, Condition, and Specification
Follow the identical procedure documented in the 16-01 article’s Step 3: remove all paper, inspect and clean the cassette interior and guides, verify paper weight is within the LCT’s specified range (typically 60–90 g/m²), check for moisture-related sheet adhesion or static bonding from dry storage, fan the stack thoroughly before reloading, square the load against the rear wall guide, and set side guides snugly without compressing the stack edges. Run a 20-sheet test after reloading with fresh, correctly specified paper before concluding paper condition is not the cause.
Step 4 — Verify LCT Elevator Operation and Upper Limit Sensor
Follow the identical procedure documented in the 16-01 article’s Step 4: load a half-full stack, observe the elevator cycle for smooth operation and a clean stop at the correct height, verify PS_HL toggles correctly in Service Mode with the paper platform raised and lowered by hand, command the elevator motor directly in Service Mode I/O check and confirm smooth operation without grinding or irregular speed, and inspect the elevator drive belt or gear assembly for stretch, glazing, or worn teeth. Replace any confirmed-failed elevator component and reset elevator position through a full down-to-up cycle before reloading paper.
Step 5 — Inspect, Clean, and Replace the LCT Feed Roller and Separation Roller
Follow the identical procedure documented in the 16-01 article’s Step 5: inspect the pickup roller surface for glazing, cracking, or embedded paper dust; inspect the separation roller/pad for the same wear criteria; always replace both as a matched set; confirm correct part numbers and directional installation orientation against the LCT unit SM; confirm retaining clips are fully seated; and reset the LCT roller replacement counter in Service Mode after installation. Run a 50-sheet test immediately after replacement, allowing for normal first-feed variation in the initial 10–20 sheets.
Step 6 — Inspect and Test the LCT Feed Sensor
Follow the identical procedure documented in the 16-01 article’s Step 6: locate PS_F per the LCT unit SM, inspect and clean the sensor window with a dry lint-free cloth, verify the sensor toggles correctly in Service Mode when paper is manually inserted and removed from the detection zone, reseat the sensor harness connector at the LCTB, and replace the sensor if it remains stuck in either state after cleaning and connector reseating.
Step 7 — Inspect the Feed-Section Transport Path Immediately Downstream of the Cassette Nip
For stop positions indicating paper reached the separation area but did not clear the feed sensor’s detection zone, inspect the short transport path between the cassette exit nip and the feed sensor for foreign objects, guide plate displacement, or debris accumulation, following the same flashlight-based multi-angle inspection technique used throughout this series. This zone is short on most LCT units, making a thorough inspection quick, but its narrow clearances can trap small fragments that are not visible from a straight-on viewing angle.
Step 8 — Verify LCTB Communication and LCT Feed Clutch in Service Mode
Follow the identical procedure documented in the 16-01 article’s Step 8: confirm the LCTB is detected and communicating in the Service Mode optional device status display; reseat the LCTB-to-engine-board harness if the LCTB is not detected; command the feed clutch/motor directly in Service Mode I/O check and observe/listen for correct engagement; measure feed clutch coil resistance if the clutch does not engage on command; and replace the LCTB only after confirming the harness and feed clutch are both functional and the fault persists.
Quick Reference — Troubleshooting by Symptom
| Symptom | Most Likely Cause | First Action |
|---|---|---|
| 15-01 on every LCT feed; paper barely moves past the cassette nip; roller surface shiny and smooth | LCT pickup roller fully glazed | Replace pickup roller and separation roller as a matched set; reset LCT roller counter in Service Mode |
| 15-01 intermittent, escalating in frequency over recent weeks | Pickup roller in early glazing stage | Inspect roller surface for early sheen even if not obviously glazed; replace if LCT copy counter is near or past the PM interval |
| 15-01 with double sheet found | Separation roller/pad worn | Replace separation roller/pad and pickup roller together as a matched set |
| 15-01 only on first feeds after a full paper reload | Elevator overshoot or drive slippage on maximum travel | Verify PS_HL triggers correctly at full-load height in Service Mode; inspect elevator drive belt for stretch |
| 15-01 only when LCT is nearly empty | Elevator drive wear at minimum stack height, or marginal roller pressure | Verify elevator rises smoothly to correct height at low stack level; inspect roller condition |
| 15-01 with skewed paper found in the feed area | Paper loaded skewed, or loose side guides | Re-square paper load against rear wall guide; verify side guides are snug |
| 15-01 immediately after roller replacement | Wrong part number, incorrect orientation, or retaining clip not seated | Verify part number and installation orientation against LCT SM; confirm retaining clip engagement |
| 15-01 with fresh paper, elevator confirmed correct, rollers recently replaced | LCT feed sensor (PS_F) contaminated or stuck OFF | Clean PS_F window; verify toggle response in Service Mode; replace if stuck OFF after cleaning |
| LCTB shows “not detected” in Service Mode optional device display | Harness disconnected, damaged, or LCTB failed internally | Reseat LCTB harness at both ends; verify LCT power; replace LCTB if harness is confirmed good |
Understanding the Code Numbering Relationship to 16-01
Jam Code 15-01 and Jam Code 16-01 describe the identical physical failure — a mechanical misfeed at the LCT’s feed section, where paper fails to exit the cassette nip and reach the feed sensor — on two different bizhub platform numbering conventions. Where a given model’s operator panel displays 15-01 rather than 16-01 depends entirely on that platform’s paper source enumeration: platforms that count the LCT as the fifth tray position in sequence after Trays 1 through 4 display 15-xx; platforms that use a separate or higher-numbered designation for the LCT display 16-xx. This is a documentation and firmware enumeration difference, not a hardware or failure-mode difference.
A technician moving between bizhub model families should expect this variance and should not treat a 15-01 code and a 16-01 code as describing different faults requiring different diagnostic approaches. Both refer to the same elevator-driven paper feed mechanism, the same pickup and separation roller assembly, and the same feed sensor detection logic. The complete diagnostic procedure, root cause categories, and component references documented in this article and cross-referenced against the 16-01 article apply interchangeably — always confirm the exact code against the specific model’s SM jam code table, but proceed with the same feed-section mechanical diagnostic approach regardless of which number is displayed.
Preventing Jam Code 15-01 From Recurring
All preventive guidance documented in the 16-01 article applies identically to 15-01, since both codes describe faults in the same physical mechanism:
- Replace the LCT pickup roller and separation roller as a matched set at the LCT-unit-specified PM interval — tracked against the LCT’s own copy counter, not the base machine’s total counter, since high-volume LCT usage frequently reaches the roller PM threshold faster than the base machine PM interval
- Clean the LCT elevator upper limit sensor (PS_HL) and the LCT feed sensor (PS_F) at every PM — paper dust accumulation on these sensor windows is the primary environmental cause of both elevation errors and false feed-sensor readings
- Inspect the LCT elevator drive belt or gear assembly at every major PM — proactive replacement at the first sign of stretch or surface glazing prevents progressive elevator positioning errors from reaching the point of producing 15-01
- Provide LCT paper loading instructions to the customer — fanning the stack before loading, avoiding mixed paper specifications, and not overfilling above the maximum fill line all reduce feed-related jam frequency without any hardware intervention
- Track the LCT roller copy counter and set a Service Mode maintenance reminder where the LCT unit supports this feature, ensuring roller replacement is triggered proactively rather than reactively
- Log LCT roller replacement with the counter value at replacement in the machine service log, allowing any future technician — regardless of whether they encounter this fault as 15-01 or 16-01 on a different machine — to immediately assess roller service life
Professional Technician Summary
Jam Code 15-01 is the LCT feed section primary misfeed — paper failed to reach the LCT feed sensor within the timing window after the feed clutch or motor was energized, meaning the paper never successfully exited the LCT cassette nip. This is a mechanical fault, diagnostically and physically identical to Jam Code 16-01 documented elsewhere in this series, differing only in the code number a specific bizhub platform’s firmware assigns to the LCT’s tray position in its enumeration scheme.
In the field, 15-01 resolves to the same three dominant causes documented for 16-01: a worn or glazed LCT pickup roller (the single most common cause, producing the characteristic intermittent-to-consistent escalation pattern); an LCT elevator system malfunction, most often traced to the upper limit sensor (PS_HL) requiring only a cleaning) or a stretched/glazed elevator drive belt; and paper condition or loading issues, particularly static-bonded paper in dry environments, which resolves entirely with correct paper handling and requires no parts.
Two service manuals are always required for 15-01 diagnosis, exactly as for 16-01: the base machine SM for the LCTB communication path and Service Mode check codes, and the LCT unit SM (PF-series) for every component inside the LCT cabinet. Pull both before opening the first access panel.
Do not treat 15-01 as a different fault requiring different technique simply because the number differs from what may be more commonly documented as 16-01 on other platforms. The elevator, the pickup roller, the separation mechanism, and the feed sensor all function identically regardless of the code number your specific machine’s operator panel displays — apply the same systematic feed-section inspection in either case.