Toshiba e-STUDIO2500c, Service Manual, Page: 291 / 402

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May 2006 © TOSHIBA TEC e-STUDIO2500c/3500c/3510c TRANSFER UNIT
13 - 3
13.3 Functions
1) Transfer belt
This belt, made of electrical resistance resin, is formed in a highly-precise technique. The drive of
the transfer belt motor rotates the drive roller and thus the transfer belt is rotated.
The length of the transfer belt may vary depending on environments such as temperature or humid-
ity. When the belt length varies, the leading position of an image also varies. Therefore, check image
position in the secondary scanning direction after installation or parts replacement because there is
difference between the environments of an installation site and a factory where the equipment was
shipped. (Although image adjustment is already performed at the shipment from the factory, this
adjustment must be performed again in the installation site.) If required, perform “Leading edge posi-
tion adjustment / Common items (05-408)”. Refer to the Service Handbook for the details of this
adjustment.
2) 1st transfer roller
When the 1st transfer bias from the high-voltage transformer is applied to this roller, a toner image is
transferred from the photoconductive drum onto the transfer belt. The spring of this roller presses
the transfer belt and the photoconductive drum to contact each other.
3) Drive roller
This roller rotates the transfer belt with the drive transmitted from the transfer belt motor. It also sup-
ports an easy contact between the transfer belt cleaning blade and the transfer belt.
4) Tension roller
This roller applies tensile force to the transfer belt with its spring.
5) 2nd transfer facing roller
This roller contacts with the 2nd transfer roller, holding the transfer belt between them to nip paper.
When the 2nd transfer bias is applied from the high-voltage power supply to the 2nd transfer facing
roller, a toner image is transferred onto paper.
To clean off the toner adhered on the 2nd transfer roller, positive bias is applied on the 2nd transfer
facing roller to transport the positively charged toner on the 2nd transfer roller to the transfer belt,
and then negative bias is applied to transport the negatively charged toner on the 2nd transfer roller
to the transfer belt.
6) Lift roller
This roller retains the contacting position of the transfer belt and the photoconductive drum.
When only a black (K) image is being developed, the 1st transfer roller cam motor lifts up the 1st
transfer rollers of yellow (Y), magenta (M) and cyan (C), together with this roller.
7) Idling roller
This roller retains the contacting position of the transfer belt and the photoconductive drum.
8) 1st transfer roller cam motor (M8)
This motor lifts up the 1st transfer rollers (Y), (M) and (C) when only a black (K) image is being
developed. Installed in the transfer belt unit, this motor drives the cam and also moves the linked
lever to lift up the 1st transfer rollers (Y), (M) and (C).
9) 1st transfer roller status detection sensor (S15)
This sensor installed in the transfer belt unit detects the timing to apply brake on the 1st transfer
roller cam motor, and also detects if the 1st transfer rollers are at their contacting or releasing posi-
tion.