Every printed page produced by a Konica Minolta bizhub machine follows a carefully controlled path from the paper tray to the output tray. During this journey, the paper passes through numerous rollers, sensors, guides, and mechanical assemblies that feed, align, print, fuse, and deliver the page with precise timing.
A modern bizhub machine can transport paper at speeds exceeding 60 pages per minute, while maintaining image registration accuracy within fractions of a millimeter. To achieve this, every stage of the paper transport system must work in perfect synchronization with the imaging system.
For service technicians, understanding the paper path is essential. Most paper jams, skewed prints, registration errors, wrinkles, and delivery problems originate somewhere along this path.
Overview of the Paper Path
The paper transport process can be divided into nine stages:
- Paper Storage
- Paper Pickup
- Paper Separation
- Registration
- Image Transfer
- Fusing
- Paper Exit
- Duplex Transport (if required)
- Delivery to the Output Tray or Finisher
Each stage relies on dedicated rollers, sensors, motors, and guide mechanisms.
Step 1: Paper Storage
Paper is stored in one of several sources:
- Tray 1
- Tray 2
- Tray 3
- Tray 4
- Large Capacity Unit (optional)
- Bypass Tray
Each tray includes:
- Adjustable side guides
- Rear paper guide
- Paper size detection mechanism
- Paper remaining detection
Correct guide adjustment is important. Loose guides can cause skewed feeding, while guides that are too tight may increase feeding resistance.
Main Components
- Paper Tray
- Side Guides
- Rear Guide
- Paper Lift Plate
- Lift Motor (model dependent)
Step 2: Paper Pickup
When printing begins, the controller activates the pickup mechanism.
The pickup roller rotates and contacts the top sheet of paper.
Only the top sheet should move forward.
The remaining sheets stay inside the tray.
Main Components
- Pickup Roller
- Pickup Solenoid
- Pickup Clutch
- Feed Motor
Common Problems
- Failure to pick up paper
- Multiple sheets feeding
- Paper remaining in tray
- Pickup roller slipping
Typical causes include:
- Worn pickup rollers
- Dirty rollers
- Weak pickup clutch
- Incorrect paper loading
Step 3: Paper Separation
After pickup, the separation system prevents multiple sheets from entering the machine.
This stage usually uses:
- Separation Roller
- Separation Pad
- Retard Roller (depending on the model)
The separation mechanism allows only one sheet to continue.
Symptoms of Failure
- Multi-sheet feeding
- Double feeding
- Frequent paper jams at the tray entrance
Step 4: Paper Registration
Before reaching the image transfer area, the paper temporarily stops at the registration rollers.
This pause allows the controller to synchronize:
- Paper position
- Drum rotation
- Intermediate Transfer Belt position
- Laser exposure timing
Once synchronization is complete, the registration rollers feed the paper forward at the exact moment required.
Main Components
- Registration Rollers
- Registration Clutch
- Registration Sensor
Importance
Registration timing determines:
- Image position
- Front margin
- Side margin
- Color alignment
Common Problems
- Skewed images
- Shifted prints
- Uneven margins
- Color registration errors
Step 5: Image Transfer
The paper now enters the transfer section.
In color bizhub machines:
- The Intermediate Transfer Belt already contains the complete CMYK image.
- The Secondary Transfer Roller applies high voltage.
- The toner image is transferred from the belt to the paper.
The paper continues moving without stopping.
Main Components
- Intermediate Transfer Belt
- Secondary Transfer Roller
- Transfer Guide Plate
Common Problems
- Light images
- Color smearing
- Incomplete transfer
- Hollow text
Step 6: Fusing
At this stage, the toner is only resting on the paper surface.
The paper passes through the fusing unit.
Inside the fuser:
- Heat melts the toner.
- Pressure forces the toner into the paper fibers.
The toner becomes permanently bonded to the paper.
Main Components
- Heating Roller or Fusing Belt
- Pressure Roller
- Thermistor
- Heater Lamp
- Thermostat
Common Problems
- Toner rubbing off
- Wrinkled paper
- Offset toner
- Fuser jams
Step 7: Paper Exit
After leaving the fuser, the paper travels toward the exit rollers.
Exit sensors confirm that the paper has successfully passed through the fusing unit.
The paper is then directed to:
- Output Tray
- Finisher
- Stapler
- Booklet Unit
- Punch Unit
Main Components
- Exit Rollers
- Exit Sensor
- Exit Guide
Common Problems
- Exit jams
- Folded corners
- Curling
- Poor stacking
Step 8: Duplex Printing
If duplex printing is selected, the paper is not delivered immediately.
Instead, diverter gates redirect it into the duplex transport path.
The paper travels through:
- Duplex Rollers
- Reversing Rollers
- Duplex Guides
The machine flips the sheet and feeds it back into the registration section for printing on the second side.
Common Problems
- Duplex jams
- Folded paper
- Misregistration on the second side
- Skew during reverse transport
Step 9: Final Delivery
Once printing is complete, the paper exits the machine.
Depending on installed options, it may be:
- Stacked
- Offset
- Stapled
- Hole punched
- Folded
- Booklet finished
The job is now complete.
Paper Detection Sensors
Throughout the paper path, sensors monitor paper movement.
Typical sensor locations include:
- Tray feed
- Registration
- Transfer section
- Fusing entrance
- Fusing exit
- Duplex path
- Exit section
- Finisher entrance
These sensors allow the controller to:
- Detect paper jams
- Monitor transport timing
- Control motor speed
- Synchronize image formation
If paper does not arrive within the expected time window, the machine stops and displays the corresponding jam code.
Motors, Rollers, and Clutches
Paper movement depends on several mechanical components working together.
Feed Motors
Provide rotational power for the paper transport system.
Rollers
Move the paper through each section while maintaining traction.
Clutches
Engage and disengage rollers at precise moments to control paper timing.
Solenoids
Operate paper gates and switching mechanisms, particularly during duplex printing.
Any failure in these components can interrupt paper movement and lead to jams or timing errors.
Common Paper Path Problems
| Symptom | Likely Cause |
|---|---|
| Paper not feeding | Worn pickup roller, pickup clutch failure, empty tray, or incorrect paper loading |
| Multiple sheets feeding | Worn separation roller or separation pad |
| Skewed paper | Misadjusted paper guides, worn registration rollers, or damaged guides |
| Image shifted on page | Registration timing problem or registration clutch issue |
| Paper jam before transfer | Registration sensor, feed rollers, or paper path obstruction |
| Paper jam inside fuser | Fusing rollers, thermistor contamination, or exit rollers |
| Wrinkled paper | Worn pressure roller, damaged guides, or unsuitable paper |
| Duplex jams | Duplex rollers, reversing mechanism, or duplex sensors |
| Exit jams | Exit rollers, exit sensor, or finisher entrance obstruction |
Preventive Maintenance Tips
Regular maintenance of the paper transport system helps prevent many common issues.
- Clean pickup, feed, and exit rollers to remove paper dust and toner residue.
- Replace pickup and separation rollers when they become worn or glazed.
- Inspect paper guides for damage and ensure they are adjusted correctly.
- Remove scraps of paper or labels from the paper path.
- Clean paper sensors and sensor actuators during scheduled maintenance.
- Verify smooth operation of duplex rollers and reversing mechanisms.
- Use paper that meets the manufacturer’s specifications for weight, size, and moisture content.
- Check for worn gears, clutches, and solenoids if intermittent feeding or timing problems occur.
Why Understanding the Paper Path Matters
The paper transport system is closely synchronized with the imaging process. A delay of even a few milliseconds can affect image placement or trigger a jam. By knowing the sequence of paper movement and the function of each roller, sensor, and clutch, technicians can quickly identify the source of feeding problems, interpret jam codes more accurately, and perform targeted repairs instead of replacing unnecessary parts.
Conclusion
The paper path in a Konica Minolta bizhub machine is a precisely engineered transport system that moves each sheet through storage, pickup, separation, registration, image transfer, fusing, duplex routing, and final delivery. Every stage depends on accurate timing between mechanical and electrical components. A thorough understanding of this paper flow enables service technicians to diagnose paper jams, skew, misregistration, and transport failures efficiently, leading to faster repairs and more reliable machine performance.