Xerox DocuColor 12/DCCS50, Руководство по обслуживанию

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10-123 DocuColor 12/DCCS50
Intermediate Belt Transfer (IBT), IBT Assembly
Principles of Operation
Reissue
• Cleaning Blade Assembly
• Second BTR Roll
• Camshaft Assembly and Cam Sensor
• Detack (DTS) Comb
• Lubricating Brush
• Pre Fuser Sensor (for the paper path)
• Exit Chute
The 2nd BTR Roll cams up to make contact with the IBT Belt. The Main Motor drives both the
2nd BTR Roll and the 2nd BTR Retract Clutch and Shaft. The Shaft with cams rotates, raising
and lowering the 2nd BTR Roll when energized by the IOT CPU and Drive PWBAs. A Flag on
the Shaft passes through a 2nd BTR Retract Home Position Sensor. The status of the Sensor
is as follows:
• Sensor blocked - 2nd BTR Roll is down (retracted from the IBT)
• Sensor transmits - 2nd BTR Roll is up (contacting the IBT)
The 2nd BTR HVPS (PSHV-L3) is located in the back of the machine and supplies a charge of
approximately -2.2 kVDC to the Contract Roll inside the IBT Assembly (NOT the 2nd BTR
Roll). The Contact Roll transfers this charge to the Back Up Roll by contact. The Back Up Roll
inside the IBT Assembly remains in contact with the inside of IBT Belt at all times. It is this Back
Up Roll that repels the toner image off the IBT Belt onto the copy material. The 2nd BTR cams
up to the IBT Belt to create a nip with the IBT Belt and the Back Up Roll behind the Belt. The
copy material has the image transferred to it at this 2nd BTR and IBT nip. The copy material
holds the toner by a residual static charge.
A Detack Comb (DTS) is located on the 2nd BTR Assembly. The purpose of this Detack Comb
is to neutralize the copy material and assure the copy material does not tack to the IBT Belt. A
DTS HVPS within the Registration Roll Assembly provides a negative charge to the Detack
Comb.
Most of the machine timing and image quality controls are generated from readings taken of
the IBT. The belt has two TR0 marks which pass under a TR0 sensor to provide a timing refer-
ence pulse. Also, toner patches are laid down onto the PR Drum, are passed to the IBT Belt,
then measured for density by the ADC (Automatic Density Control) Sensor. This allows the
machine to maintain a consistent toner level for the same input color.
IBT Assembly
CAUTION
The IBT Belt is fragile. It can be damaged by handling with bare hands or having items (i.e.
screws, tools or even excess dust/dirt) dropped on it.
The IBT Assembly has its own tray with slide tracks which allow this assembly to be pulled out
for access and servicing.
Figure 2 shows some of the components in the IBT Assembly.
Detailed descriptions of the components follow.
IBT Belt
The IBT uses a carbon-impregnated polyamid belt that carries the image toner from the Photo-
receptor (PR) Drum to the paper. This belt holds a residual charge from the First Bias Transfer
Roll (BTR), which attracts the toner particles and holds them until that part of the belt reaches
the nip between the Second BTR and the Back Up Roll. At that point, the voltage from the Back
Up Roll causes the toner particles to be expelled from the Belt to the blank copy material. The
Belt has a circumference of 527.91 mm, which is twice the circumference of the PR Drum. At a
process speed of 220 mm/sec., the belt takes 2.399 sec. to complete one complete revolution.
The belt has two TR0 strips, separated by one-half the belt circumference and located on the
back edge of the belt. As shown in
Figure 2 , there are eight rolls inside the belt:
• Steering Roll keeps the IBT on track and centered on the rolls.
• Tension Roll keeps the belt taut.
• First Idler Roll is passive and directs the belt towards the Photoreceptor Drum. It is
located between the Tension Roll and the First BTR Roll.
• First BTR Roll holds the charge which attracts the toner from the Photoreceptor Drum to
the belt
• Drive Roll is driven by the PR Drum Motor, which causes the IBT Belt to turn. It also
helps keep the belt on track.
• Contact Roll receives the charge from the 2nd BTR HVPS and transfers this charge to
the Back Up Roll.
• Back Up Roll provides a charge for toner transfer from the IBT Belt to the copy material.
It also creates a nip with the Second BTR Roll, through which both the IBT Belt and the
copy material passes through.
• Second Idler Roll is passive and positions the belt between the Steering Roll and the
Backup Roll/Second BTR nip.