Epson C 2900 Manual

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Confidential 3.9.2 Data Flow
Print data (electric signal) from the printer controller flows as shown below until it is turned into a print.
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3.10 Duplex
3.10.1 Major functions
- CLUTCH ASSY EXIT
Transmits the driving power from the DRIVE ASSY EXIT to Roll Assy Exit in the Fuser.
When the clutch operates, the Roll Assy Exit rotates in the reverse direction.
The clutch is stopped when the paper reached the Duplex.
- DRIVE ASSY DUP (PL11.2.5)
The DRIVE ASSY DUP supplies the driving power to the Lower Roll (ROLLER ASSY DUP) and 
Upper Roll (ROLL ASSY DUP1). (Refer to 6.5 DRIVE ASSY DUP)
- DRIVE ASSY EXIT (PL11.2.2)
The DRIVE ASSY EXIT supplies the driving power to the Roll Assy Exit in the Fuser Unit. (Refer to 
6.5 DRIVE ASSY DUP)
- PWBA DUP (PL11.1.16)
The PWBA DUP controls motor and clutch.
MiS06029KA
CLUTCH ASSY  EXIT
ROLLER ASSY DUP (Lower Roll)ROLLER ASSY DUP (Upper Roll)
PWBA DUP DRIVE ASSY  DUPDRIVE ASSY  EXIT 
						

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3.11 250 Paper Tray
3.11.1 Major functions 250 Paper Tray
- GUIDE SIDE ASSY R (PL12.5.8) / GUIDE SIDE L (PL12.5.6)
The GUIDE SIDE ASSY R and GUIDE SIDE L can move at a right angle to the paper transfer direc-
tion to align the paper width.
- END GUIDE
The END GUIDE can move in the paper transfer direction to determine the paper size.
- HOLDER ASSY RETARD (PL12.5)
The HOLDER ASSY RETARD and the FEED ROLLER pinch the paper to prevent multiple sheet 
feed.
- PLATE ASSY BOTTOM (PL12.5.2)
PLATE ASSY BOTTOM is locked to the bottom side when paper tray is pulled out from the paper 
feeder and unlocked when paper tray is installed to the paper feeder. Pushes the paper against the 
feed roll using a spring tension.
GUIDE SIDE LGUIDE SIDE ASSY R
HOLDER ASSY RETARD (Retard Roller) END GUIDE
PLATE ASSY  BOTTOM
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Confidential 3.11.2 Major functions (Paper Feeder)
- SENSOR PHOTO (No Paper Sensor:PL12.4.13)
Detects the presence/absence of paper in the paper tray based on the position of ACTUATOR NO 
PAPER (PL12.4.19). (No paper: Sensor beam is intercepted)
- SOLENOID FEED MSI (PL12.2.15)
Transmits the driving power from the MOTOR ASSY SUB (PL12.2.16) to ROLL ASSY FEED. (Refer 
to 6.6 MOTOR ASSY SUB)
- ROLL ASSY FEED (PL12.4.4)
When the SOLENOID FEED MSI operates, the ROLL ASSY FEED starts rotating and the ROLL 
ASSY FEED feeds the paper. (Refer to 6.6 MOTOR ASSY SUB)
- SENSOR PHOTO (PAPER PATH SENSOR:PL12.4.13)
It detects when the paper front end reaches the CHUTE ASSY TURN (PL12.4.1).
ON: The paper activates the actuator.
- CLUTCH ASSY DRV (PL12.2.6)
Transmits the driving power from the MOTOR ASSY SUB (PL12.2.16) to ROLL ASSY REGI 
(PL12.4.9) and ROLL REGI METAL (PL12.4.10).
- MOTOR ASSY SUB (PL12.2.16)
The MOTOR ASSY SUB is driving the rolls of the option feeder. (Refer to 6.6 MOTOR ASSY SUB)
- PWBA FEED H (PL12.2.1)
The PWBA FEED H controls motor, sensor and clutch. 
						

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MiS06031KA
SENSOR PHOTO
(Tray2 No Paper Sensor)
SENSOR PHOTO
(Paper Path Sensor)TURN ROLL RUBBER
(ROLL ASSY  REGI)
TURN ROLL METAL
(ROLL REGI METAL) CLUTCH ASSY  DRVROLL ASSY  FEED
SOLENOID FEED MSI
MOTOR ASSY  SUB PWBA FEED H 
						

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4. Operation Modes
4.1 Operation Modes
For the operation of the printer, the following four modes are provided.
- READY mode
The printer is ready for printing.
- PRINTING mode
The printer is under printing.
- Sleep mode (Energy star)
The printer is under power saving.
- Deep sleep mode
The printer is under power saving. 
						

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5. Control
5.1 Control of Paper Size
The printer doesn’t have switches for detecting paper size, and only length of paper is detected by the 
Regi Sensor when feeding paper. If printing data and paper size don’t match, error is sent to the ESS.
5.2 ROS Light Quantity Control
The image data are entered to the laser diodes in the ROS as electric signals (data are expressed with 
high and low voltage values), and the laser diodes convert the image data from electric signals to opti-
cal signals (data are expressed with blinking laser beams).
Variations in light quantity of laser beams or variations in optical system (such as lenses) or drum sen-
sitivity cannot attain a proper electrostatic image, therefore, the laser beam light quantity is monitored 
and controlled by the laser diodes.
The ROS in this printer has four laser diodes for yellow, magenta, cyan, and black respectively, and the 
light quantity is automatically adjusted for each color. 
						

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5.3 Process Control
For a stable printing, the parameters related to the image forming must be corrected as necessary. The 
control of the entire printing process including parameter correction control is called process control.
Mainly, the process control is performed in the following two methods, both of which are performed 
after every 25 cumulative prints upon termination of a print run or during a continuous run.:
• Potential control
• Toner density control
To supplement these two controls, the following controls are provided:
• High Area Coverage Mode
• Admix Mode
5.3.1 Potential Control
To attain stable printing image density, the drum charging voltage, the developing DC voltage and the 
ROS light amount are adjusted according to the developing capability of each color carrier that varies 
momentarily. The adjusted drum charging voltage, the developing DC voltage and the ROS light 
amount are fed back to keep the printing image density constant.
The outline of control is as follows.
1) The HUMIDITY SENSOR (temperature and humidity sensor) detects the temperature and 
humidity.
2) The patches of respective colors (yellow, magenta, cyan, and black) for the potential control are 
generated and transferred on the Belt.
3) The ADC Sensor (density sensor) detects the density of the patch on Belt.
4) The drum charging voltage, the developing DC voltage and the ROS light amount are adjusted for 
each color according to the detected patch density. 
						

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Confidential 5.3.2 Toner Density Control
The toner density must be kept constant to attain stable printing image. The control system for this pur-
pose is called toner density control.
1) PCDC (Pixel Count Dispense Control)
The quantity of the toner to be consumed in the developing process is calculated by counting the 
video signals entered to the ROS. The quantity of the toner to be consumed is calculated by the 
toner dispensing time. The toner motor is driven based on the calculated toner dispensing time 
when supplying the toner to the developer.
2) ADC (Auto Density Control)
The patches of respective colors (yellow, magenta, cyan, and black) for the toner density control are 
generated under specified potential condition, and transferred on the Belt. The ADC Sensor mea-
sures this density. The measured value is compared with the reference value. If the toner density is 
lower, the toner dispense quantity is increased at the next printing, or if the toner density is higher, 
the toner dispense quantity is reduced at the next printing. The toner dispense quantity is calculated 
by the toner dispense time. This calculation is made for each color.
5.3.3 High Area Coverage Mode
A continuous printing of any image of area coverage exceeding extra toner dispense capability causes 
the toner density in the developer to be lowered.
The High Area Coverage Mode postpones the next page feed and dispenses the toner during this time, 
if the toner dispense time reached the specified value during a continuous printing.
5.3.4 Admix Mode
This mode prevents the toner density from being lowered, whenever the value of the toner density con-
trol patch measured by the ADC Sensor falls far below the standard value, by performing extra toner 
dispensation. If the toner density level cannot be recovered even after this operation, it is judged that 
the toner has run out.
5.3.5 ADC Sensor Adjustment
The ADC Sensor is a reflection type sensor that irradiates the light from its LED onto the target and 
detects the reflected light at its photoreceptor and outputs electric signals responsive to the amount of 
the detected light. To ensure an accurate patch density measurement, the surfaces of the ADC Sensor 
is cleaned to remove soil due to toner, etc., and the light amount adjustment is made so that the 
reflected light amount satisfies the prescribed value, when creating the patch for potential control and 
toner density control. 
						

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5.4 Color Registration Control
The printer uses a tandem system where the drums and developers are arranged respectively for each 
of yellow, magenta, cyan, and black colors. Since the images are formed on the drum of each color to 
be overlaid one another, a color shift may occur. The color registration control calculates how much the 
registration is shifted, and adjusts the ROS write timing.
The lateral registration control adjusts all of four colors in lateral directions.
The color registration control is made from a change in inside temperature and the print count at the 
execution of the process control.
The control is outlined below:
1) With no toner on the Belt, the output value of ADC Sensor is measured to determine the thresh-
old value.
2) The patches for color registration control are generated on the Belt. These patches are com-
posed of 10mm lines of K, C, K, M, K, and Y in this order.
3) The density of patches generated by the ADC Sensor is read.
4) The shift correction amount is calculated from the threshold value determined in 1) and the patch 
density measured in 3).
5) The ROS write timing is changed according to the shift correction amount.