Canon imageCLASS MF8450c, Руководство по обслуживанию

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Chapter 7
7-18
7.3.6 Developing Cylinder Engagement/disengagement Control
0019-5026
imageCLASS MF9170c / imageCLASS MF9150c / imageCLASS MF8450c
In the machine, the developing cylinder is engaged with or disengaged from the photosensitive drum as necessary for the following purposes.
- To reduce the color photosensitive drum consumption at the time of monochrome printing
- To prevent lines of the photosensitive drum due to engagement with the developing cylinder
- To prevent toner transfer when printing is not performed
The developing cylinder engagement/disengagement control is executed at the following timing.
- Multiple initial rotations at power-on
- Image stabilization control
- Printing operation
The status of engagement/disengagement during printing operation differs depending on the printing mode (monochrome or color mode).
T-7-3
*: Thick paper, envelope, rough paper, small-size paper, thin paper (H/H environment), thin paper (when thin paper/rough paper is specified in the
special control mode)
Explanation of operation
The toner cartridge consists of the upper part where the photosensitive drum is attached and the lower part where the developing cylinder is attached (developing
assembly).
When the developing disengagement solenoid (Bk: SL5015, YMC: SL5014) is turned OFF, the developing disengagement cam moves up the rear side of the de-
veloping assembly, so the developing cylinder is disengaged from the photosensitive drum with the principle of leverage.
When the DC controller turns ON the developing disengagement solenoid, the drive of the fixing motor (M1) is sent to the developing disengagement cam, causing
the cam to rotate. When the radius of the developing disengagement cam becomes shorter than the distance between the cam and the developing assembly, the
developing cylinder is engaged with the photosensitive drum by the power of a spring.
The engagement/disengagement condition is detected by the developing disengagement sensor (Bk: SR711, YMC: SR712) based on the direction of the developing
disengagement cam.
F-7-23
MEMO:
The machine uses a contact development method, in which the developing cylinder is engaged with the photosensitive drum.
- At color printing, developing cylinders of all colors are engaged with the photosensitive drum, but, at monochrome printing, only the black-color developing
cylinder is engaged with it. By disengaging developing cylinders of colors other than black from the drum, the machine reduces the color photosensitive drum
consumption at monochrome printing.
- When the machine stops for a long period of time, lines occur in the area where the developing cylinder and the photosensitive drum come into contact. To prevent
this symptom, the developing cylinder is disengaged from the photosensitive drum.
- When printing is not performed, the toner on the developing cylinder adheres to the photosensitive drum. To prevent this symptom, the developing cylinder is
disengaged from the photosensitive drum.
- This control works with the transfer roller engagement/disengagement operation. For details, refer to "Transfer Roller Engagement/disengagement Control".
Color mode Developing cylinder Drum motor drive
Color printing All color cylinders are engaged. All color motors are driven.
Monochrome printing Plain paper, Transparency Only the black color cylinder is engaged. Only the black color motor is driven.
Others* All color motors are driven.
Power-off/standby All color cylinders are disengaged. Stopped
Error Codes:
E015 Developing disengagement abnormality
When the machine is placed in the following condition, it stops operation and displays the error code on the control panel.
- The direction of the developing disengagement cam does not change from the home position after a specified period of time when the developing cylinder
is disengaged from the drum.
- The direction of the developing disengagement cam does not return to the home position after a specified period of time when the developing cylinder is
engaged with the drum.
Toner cartridge
Spring
Photosensitive drum
Developing cylinder
Developing assembly Developing
disengagement cam
a. When being engaged b. When being disengaged