Ricoh B230 Service Manual

							 
SM 6-23 B230/B237 
Detailed 
Descriptions 
6.5.2 OPTICAL PATH 
 
The laser beams for black [A] and yellow [B] are directed to the upper part of the polygon 
mirror [C]. Laser beams for magenta [E] and black [D] are directed to the lower part of the 
polygon mirror. The LD mirrors (see the previous page) deflect the laser beams for 
magenta and black towards the lower polygon mirror.   
The WTL [F] corrects the main scan line. Without this component, the line bends out 
towards the middle of the main scan. The central bend of the WTL is adjusted in the factory. 
The speed of the polygon mirror depends on the selected mode and model (see below). 
 
Mode Polygon motor 
speed (rpm) Process line 
speed (mm/s) Print speed 
(ppm) 
Plain 
/Middle Thick   32,598 138 mm/s C1a: 25 
C1b: 30 
OHP/Thick 36,378 77 mm/s  16 
  
						

							 
B230/B237 6-24  SM 
6.5.3  LASER SYNCHRONIZING DETECTORS 
 
Overview 
The machine has four laser synchronizing detector boards (LSD). There is one at each 
corner of the laser optics-housing unit. 
The four LSD boards detect the following: 
ƒ  [A]: Scanning end position for yellow and cyan 
ƒ  [B]: Scanning start position for yellow and cyan 
ƒ  [C]: Scanning end position for magenta and black 
ƒ  [D]: Scanning start position for magenta and black.   
The machine recognizes each color from the time that they are detected.   
Main Scan Start Detection 
For magenta and black, the LSD at the rear detects the start of the main scan. For yellow 
and cyan, the LSD at the front detects the start of the main scan. The arrow [E] indicates 
the scanning direction. 
Clock Frequency Adjustment 
Each LSD ensures that the number of laser clock pulses in the main scan is constant. If the 
count for one particular beam varies from normal, the LD clock frequency for that beam is 
adjusted. 
If the board at the end position is defective, the clock frequency cannot be adjusted. At this 
time, you must disable the detection feature with SP2-186-1.  
						

							 
SM 6-25 B230/B237 
Detailed 
Descriptions 
6.5.4 LD SAFETY SWITCH 
 
A relay on the PSU ensures technician and user safety. It also prevents the laser beam 
from turning on during servicing. This relay turns off when the front cover, upper left cover, 
or right door is opened. At this time it cuts the power (+5V) supplied to the LD board for 
each color through the BICU. 
Two safety switches are used to turn the relay off. One switch is used for the front door. 
Another safety switch is used for the right door. 
ƒ  PMAC: Precise Pulse Modulation ASIC on C-MOS technology 
ƒ  LDB: LD Drive Board (included in the LD Unit) 
Error Messages 
Along with other switches, the LD safety switches help show error messages related to 
external covers. When one or more covers are open, the messages, “Cover is open.” and 
“Close the indicated cover,” show with a diagram. The diagram shows which cover is open.  
						

							 
B230/B237 6-26  SM 
6.5.5  AUTOMATIC LINE POSITION ADJUSTMENT 
Overview 
CC, KK, YY, MM: Spaces between two lines of the same color 
KC, KY, KM: Spaces between a black line and a color line 
 
During automatic line position adjustment, the line patterns above are created eight times 
on the transfer belt. The spaces between the lines (CC, KK, YY, MM, KC, KY, KM) are 
measured by the front, center, and rear ID sensors. The controller takes the average of the 
spaces. Then it adjusts the following positions and magnification: 
ƒ  Sub scan line position for CMY   
ƒ  Main scan line position for CMY 
ƒ  Magnification ratio for CKMY 
ƒ  Skew for CMY 
The transfer belt-cleaning unit cleans the transfer belt after the patterns are measured. 
SC285 shows if an error is detected four times consecutively. 
Summary of Each Adjustment 
Sub scan line position for YCM 
The adjustment of the sub-scan line position for YCM is based on the line position for K 
(color registration). The machine measures the gaps between the lines of each color in the 
pattern on the transfer belt. If the gaps for a color are not correct, the machine moves the 
image of the color up or down the sub scan axis. To do this, it changes the laser write  
						

							 
SM 6-27 B230/B237 
Detailed 
Descriptions 
timing for that color. 
Main scan line position for YCM 
If the machine detects that the image is out of position in the main scan direction, it 
changes the laser write start timing for each scan line. 
Magnification adjustment for KYCM 
If the machine detects that magnification adjustment is necessary, it changes the LD clock 
frequency for the required color. 
Skew for YCM 
The adjustment of the skew for YCM is based on the line position for K. 
Adjustment Conditions 
Line position adjustment can be turned on or off with SP2-193-001. However, it is normally 
recommended to turn on this function.   
Line position adjustment timing depends on several SP mode settings. These are 
described below.   
Δt = Time since the previous line position adjustment   
ΔT = Temperature change between the temperature of the previous line position 
adjustment and the current temperature 
Forced (SP2-111-001 to -003): 
This activates the line position adjustment manually. There are three types of line position 
adjustment mode. See the SP table for details. 
Initial: 
This starts automatically when the power is turned on, or when the machine recovers from 
the energy saver mode. 
Line position adjustment is automatically done twice if one of these conditions occurs: 
1. Δt > Time threshold (SP2-193-012: [default: 600 minutes])   
2. ΔT > Temperature threshold (SP2-193-011: [default: 10°C])   
Line position adjustment is automatically done once if one of these conditions occurs: 
1. Δt > Time threshold (SP2-193-009: [default: 300 minutes])   
2. ΔT > Temperature threshold (SP2-193-008: [default: 5°C]) 
Interval: During job: 
This interrupts printing and then starts automatically if one of these conditions occurs when 
the machine checks at the sheet interval specified with SP3-512-001 (default: 30 page). 
Line position adjustment is automatically done once if one of these conditions occurs: 
1. Δt > Time threshold (SP2-193-009: [default: 300 minutes]) 
2. ΔT > Temperature threshold (SP2-193-008: [default: 5°C]) 
3.  B/W counter (SP3-510-005) + Color counter (SP3-510-006) > Output threshold for all  
						

							 
B230/B237 6-28  SM 
outputs (SP2-193-004: [default: 200 pages) 
4.  Color counter > Output threshold for color outputs (SP2-193-005: [default: 200 pages]) 
Interval: Job end: 
This starts automatically at the end of a print job. 
Line position adjustment is automatically done once if one of these conditions occurs: 
1. Δt > Time threshold (SP2-193-009: [default: 300 minutes]) 
2. ΔT > Temperature threshold (SP2-193-008: [default: 5°C]) 
3.  B/W counter (SP3-510-005) + Color counter (SP3-510-006) > Output threshold for all 
outputs (SP2-193-002: [default: 500 pages) 
4.  Color counter > Output threshold for color outputs (SP2-193-003: [default: 200 pages]) 
Front door open/close: 
This starts automatically when the front door is opened/closed. 
Line position adjustment is automatically done once if one of these conditions occurs: 
1. Δt > Time threshold (SP2-193-009: [default: 300 minutes]) 
2. ΔT > Temperature threshold (SP2-193-008: [default: 5°C]) 
In stand-by mode: 
This is automatically done once if both conditions occur at the same time. However, it is 
not done if the machine is in the energy saver mode. 
1. Δt > Time threshold (SP2-193-009: [default: 300 minutes]) or ΔT > Temperature 
threshold (SP2-193-008: [default: 5°C]) 
2.  B/W counter (SP3-510-005) > Output threshold for B/W outputs (SP2-193-002: 
[default: 500 pages]) or Color counter > Output threshold for color outputs 
(SP2-193-003: [default: 200 pages]) 
After new PCU or Image Transfer Belt Unit detection 
When the machine detects a new unit (one of the PCUs or the Image Transfer Belt Unit), 
line position adjustment is automatically done twice. 
If the main scan magnification changes 
This is detected by the main scan synchronization detectors at each end of the scan line for 
each color. 
If the magnification changes by more than 1% (threshold adjustable SP2-193-010), line 
position adjustment is done again.  
						

							 
SM 6-29 B230/B237 
Detailed 
Descriptions 
Main Scan Skew Adjustment 
 
The WTL positioning motors for magenta [A], cyan [B], and yellow [C] adjust the angle of 
the WTL [D] respectively, based on the WTL position for black. This mechanism corrects 
main scan skew.   
ID Sensors 
 
There are seven ID sensors. Three of them are for the line position adjustment. Four of 
them are for process control. The ID sensor shutter [A] covers the sensors when the 
machine is idle. 
When the ID sensor shutter solenoid [B] is activated, ID sensor shutter [A] slides to the left. 
This mechanism prevents the ID sensors from becoming dirty with toner or dust.  
						

							 
B230/B237 6-30  SM 
Shutter Mechanism 
 
The laser optics housing unit has a shutter. As a result, toner and other dust do not fall on 
the glass of the laser optics housing. The shutter motor [A] moves the shutter [B] in the 
direction of the arrow with the cam [C] (to open: black arrow direction, to close: white arrow 
direction).  
First, the actuator [D] stays at the shutter closed sensor [E]. The shutter motor opens the 
shutter and the actuator moves to the shutter open sensor position [F] after the polygon 
motor has turned on.   
Finally, the shutter motor closes the shutter and the actuator moves back to the shutter 
closed sensor position [E] after the polygon motor has turned off.     
One of SC290 to 297 occurs if the output of the shutter open [F] or closed sensor [E] does 
not change after the shutter motor turned on.  
						

							 
SM 6-31 B230/B237 
Detailed 
Descriptions 
6.6  PCU (PHOTO CONDUCTOR UNIT) 
6.6.1 OVERVIEW 
 
 
1. OPC drum 
2. Cleaning blade 
3. Brush roller   
4. Lubricant bar 
5. Lubricant application blade 
6. Cleaning roller (charge roller) 7. Charge roller (non-contact) 
8. TD sensor/ID chip 
9. Mixing auger 
10. Development roller 
11. Inner pressure adjustment filter 
 
This machine has four tandem PCUs. Therefore, four color developments are possible 
during one paper path. This improves the productivity of outputs in color printing mode. 
Each PCU contains identical components (drum unit, development unit and so on), but the 
PCUs are not interchangeable.     
The diameter of the drum is 40 mm (circumference: about 125.7 mm). 
The photoconductor gap between a drum and the corresponding development roller is not 
possible to adjust because these are assembled as a PCU at the factory.   
The ID chip is part of the TD sensor assembly. The ID chip contains counters and other 
data about the PCU, drum unit, and development unit. If you replace the development unit 
with a new one, the counter information for the drum unit is not kept on the new ID chip.  
						

							 
B230/B237 6-32  SM 
6.6.2  AROUND THE DRUM 
Drum Drive 
 
The drum/development drive motor-K [A] drives the drum unit for black.   
The drum drive motor-CMY [B] drives the drum units for magenta, cyan, and yellow. Using 
one motor to drive these three drums reduces CMY color misalignment. 
Both motors are brush-less DC motors. This helps to reduce the drive noise.   
Phase Control Mechanism 
The machine uses the drum gear position sensors to detect if the drum motors rotate. 
SC380 shows when it detects that the drum motor is not moving. These sensors also help 
the machine to initialize the relative positions of the gears when the main switch is turned 
on, and during initializing. This prevents phase fluctuation between printouts that is caused 
by incorrect gear meshing at the start of the job. 
There is an interrupter on each of the black [C] and magenta [D] drum gears. The drum 
gear position sensors [E][F] detect the positions of these interrupters. This mechanism 
makes sure that output quality does not vary. The cyan and yellow drum gears operate with 
the magenta drum gear because these three drum gears are linked through other gears. 
In the ready status, if the gears are not in the correct position, the machine adjusts the 
position of the black drum gear. 
The relative positions of the gears are adjusted every 30 jobs.