Theory Of Operation; Por Sequence; Printer Control; Paper Path Information - Konica Minolta bizhub 4020 Service Manual

12. Theory of operation

12.1 POR sequence

At power on, the engine code goes through a series of tests to verify hardware integrity. If a hardware
failure is detected, it will be reported to the printer. If the POR sequence cannot be completed
successfully, the printer may post an error message identifying service may be needed.

12.2 Printer control

The printer uses a single processor for both RIP and engine functions. The raster image processor (RIP)
code performs system responsibilities such as PC connection, LAN, ISP attachments, and bitmap
generation. The engine code performs tasks related to the operation of the electrical and mechanical
device systems such as motors, lasers, power supplies, and fusers. The NVRAMs are located on the
controller board and control panel, replacement of either the controller board or control panel will pull or
mirror NVRAM data from each other.

12.3 Paper path information

12.3.1 Input tray

Component functions for feeding from the tray:

Tray present sensor—Detects if the tray is inserted

Media present sensor—Detects whether the media level is empty or low.

Pick/Lift motor—Supplies the mechanical power requirements of the lift plate and the pick rollers.
When feeding media, the front part of the lift plate is raised, pressing the media to the pick rollers. The
pick rollers rotate to feed the media to the separator rolls. The separator rolls rotate in a direction
opposite to the pick rollers. This ensures that sheets are fed one at a time. The media is then fed to the
secondary input roller and then to the first input roller.

12.3.2 Multipurpose feeder (MPF)

The driving force from the main drive motor is transmitted through the MPF gearbox. When the MPF
solenoid activates, it allows the MPF sector gear linked to the MPF gearbox to rotate. The MPF pick roll
shaft is connected to the MPF sector gear.
The MPF can be accessed by opening the MPF tray on the front door. In an MPF paper feed, the MPF
paper present sensor detects the media. The instant the MPF pick roll shaft rotates, the cams on each
bizhub 4020/3320 Service Manual
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