Ricoh B230 Service Manual

							 
SM 6-3 B230/B237 
Detailed 
Descriptions 
6.1.3 DRIVE LAYOUT 
 
 
1. Scanner motor:  Drives the scanner unit. 
2. Drum drive 
motor-CMY: Drives the drums for magenta, cyan, and yellow. 
3.ITB (Image Transfer 
Belt) contact motor: Moves the ITB into contact and away from the color PCUs. 
4. Toner transport motor: Drives the toner attraction pumps and the toner collection coils 
from the PCUs, from the transfer belt unit, and inside the toner 
collection bottle. Also rotates the toner bottles. 
5. Development drive 
motor-CMY: Drives the color development units (magenta/cyan/yellow). 
6. Development clutch-K  Turns on/off the drive power to the development unit-K.  
						

							 
B230/B237 6-4  SM 
7. Paper feed clutch  Switches the drive power between the tray 1 and tray 2. 
8. Paper feed motor:  Drives the paper feed mechanisms (tray 1/tray 2/by-pass tray). 
9. Drum/Development 
drive motor-K: Drives the black drum and development unit. 
10. Registration motor:  Drives the registration roller. 
11. Paper transfer 
contact motor Moves the paper transfer roller in contact with the image 
transfer belt. 
12. ITB drive motor:  Drives the image transfer belt unit. 
13. Fusing/paper exit 
motor: Drives the fusing unit and paper exit section. 
6.1.4 BOARD STRUCTURE 
Overview 
 
 
ƒ  In the diagram, ‘MLB’ is the File Format Converter 
Descriptions 
BICU (Base Engine Control Unit): 
The BICU controls all the mechanical components. The BICU has six CPUs. The CPUs  
						

							 
SM 6-5 B230/B237 
Detailed 
Descriptions 
control the following functions: 
ƒ Engine sequence 
ƒ Engine operation 
ƒ  Polygon motor control 
ƒ Image processing 
Controller: 
The controller connects to the BICU through a PCI bus. The controller handles the 
following functions: 
ƒ Machine-to-host interface 
ƒ  Operation panel interface 
ƒ Network interface 
ƒ  Interfacing and control of the optional IEEE1284, Bluetooth, IEEE1394, IEEE802.11b 
(wireless LAN), USB Host, HDD, and DRAM DIMM 
LD Drive Board: 
This is the laser diode drive circuit board. 
SBU: 
The Sensor Board Unit has a CCD (charge-coupled device) and an analog-to-digital 
conversion circuit. 
Operation Panel Board: 
This controls the display panel, the LED and the keypad. 
Scanner I/O Board (SIO): 
The scanner I/O board is a circuit board that transmits control signals, image data, and 
electricity. 
I/O Board (IOB): 
Contains drivers for motors and other mechanical components. 
Motherboard: 
Connects the FCU board to the BICU. This board is supplied with the optional fax unit. 
FCU: 
The FCU (fax controller unit) controls the fax programs and communicates with the 
controller to share copier resources.  
						

							 
B230/B237 6-6  SM 
6.1.5 PRINTING PROCESS 
 
This machine uses four PCUs, and four laser beams for color printing. Each PCU consists 
of the drum unit and the development unit. Each drum unit has a drum, charge roller, 
cleaning brush, and blade. From the left, the PCU stations are yellow, cyan, magenta, and 
black. 
The drum [A] is charged with a negative voltage, and is exposed by the laser from the laser 
optics housing unit [B]. The laser neutralizes the negative charge on the surface of the 
drum. So, the white parts of the image correspond to areas of the drum that still have a high 
negative charge. The toner has a negative charge, and it moves to the areas of the drum 
that have the smallest negative charge (i.e., the areas written by the laser beam).   
The image on each drum is moved to the transfer belt by the positive bias that is applied to 
the transfer belt [C]. All four toners are put on the belt at the same time. Then, the 
completed four-color image is moved to the paper by a negative charge applied to the ITB 
drive roller [D] (the transfer roller [E] is an idle roller). 
1. Drum charge: The charge roller gives the drum a negative charge 
2. Laser exposure: The laser beam from the laser diode (LD) goes through the lens and 
mirrors and reaches the drum. The machine turns the laser beam on and off to make a 
latent image on the drum. 
3. Development: The development roller carries negatively charged toner to the latent 
image on the drum surface. This machine uses four independent development units 
(one for each color). 
4. Transfer: 
Image transfer: Bias rollers opposite the OPC drums transfer toner from the drums to 
the transfer belt. Four toner images are super-imposed onto the belt.   
Paper transfer: Then, the ITB drive roller pushes the toner from the transfer belt to the 
paper (the transfer roller is an idle roller).    
						

							 
SM 6-7 B230/B237 
Detailed 
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5. Cleaning for OPC drum: The cleaning brush and blade remove remaining toner on 
the drum surface after image transfer to the paper. 
6. Quenching for OPC drum: Quenching is done by illuminating the whole area of the 
drum with the laser at the end of every job. 
7. Cleaning and quenching for transfer belt: The cleaning brush and blade clean the 
belt surface. The grounding roller inside the transfer belt unit removes the remaining 
charge on the belt. 
 
8.  ID sensors: The ID sensors detect the density of ID sensor patterns on the transfer 
belt.  
The ID sensor board contains three ID sensors for the line position adjustment (front, 
center, and rear) and four ID sensors for the process control. On this board, there are 7 
ID sensors in total, as follows.   
ƒ  [A]: Line position adjustment (front) 
ƒ  [B] Process control (K) 
ƒ  [C]: Process control (C) 
ƒ  [D]: Line position adjustment (centre) 
ƒ  [E] Process control (M) 
ƒ  [F]: Process control (Y) 
ƒ  [G]: Line position adjustment (rear) 
The ID sensor output is used for the following: 
ƒ  Process control and for automatic line position 
ƒ Skew correction 
ƒ  Color registration adjustments for the latent image.  
						

							 
B230/B237 6-8  SM 
6.2 PROCESS CONTROL 
6.2.1 OVERVIEW 
This machine has the following two forms of process control: 
ƒ Potential control 
ƒ  Toner supply control 
The following machine components are used for process control: 
ƒ  Four ID (image density) sensors (black, magenta, cyan and yellow).   
ƒ TD sensor. 
Normally, process control is not disabled. If process control is disabled, fixed supply mode 
is used for toner supply, and the VREF stored in SP 3222 is used. 
6.2.2 POTENTIAL CONTROL 
Overview 
The machine determines VD using the ID sensor output, and then determines VB and VL. 
ƒ V
D: Drum potential without exposure – to adjust this, the machine adjusts the charge 
roller voltage. 
ƒ V
B: Development bias 
ƒ V
L: Drum potential at the strongest exposure – to adjust this, the machine adjusts the 
laser power 
At the same time, the machine also determines VREF: Reference TD sensor output, used 
for toner supply control 
If potential control is disabled (SP3-041-001 is set to 0), V
D and VB are fixed by the 
following SP mode settings. 
ƒ  SP2-005 for V
D, SP2-229 for VB  
If LD power control is disabled (SP3-041-002 is set to 0), the LD power is fixed by the 
following SP mode setting. 
ƒ  SP2-221 for V
L  
Process Control Self Check 
This machine uses the process control self check method to do the potential control. The 
machine uses seven types of process control self check. These are categorized according 
to their execution timing. 
The counter (SP3-510) is reset if a self-check is done (except for a forced self-check). 
ΔT = Temperature change between the temperature of the previous process control and 
the current temperature  
						

							 
SM 6-9 B230/B237 
Detailed 
Descriptions 
ΔRH = RH (Relative Humidity) change between the relative humidity of the previous 
process control and the current relative humidity 
ΔAH = AH (Absolute Humidity) change between the absolute humidity of the previous 
process control and the current absolute humidity 
1.  Manual execution (forced): This is done when SP3-011-1 is used. 
2. Initial 
This starts automatically when the power is turned on, or, when the machine recovers 
from energy saver mode.   
This is done automatically if one of these conditions occurs. 
ƒ a) ΔT is greater than or equal to Temperature Threshold (SP3-522-003: 10°C) 
ƒ b) ΔRH is greater than or equal to Relative Humidity Threshold (SP3-522-004: 
50%RH) 
ƒ c) ΔAH is greater than or equal to Absolute Humidity Threshold (SP3-522-005: 6 
g/m
3) 
ƒ  d) If the following conditions both occur. 
BW Counter (SP3-510-003) is greater than or equal to Execution Interval 
(SP3-511-005)  
OR 
FC Counter (SP3-510-004) is greater than or equal to Execution Interval 
(SP3-511-006) 
Non-use Time is greater than or equal to SP3522-002 (default: 6 hours) 
3.  Interval: Job End 
This starts automatically at the end of a print job if the following condition occurs: 
BW Counter (SP3-510-001) is greater than or equal to Execution Interval 
(SP3-515-001)  
OR 
FC Counter (SP3-510-002) is greater than or equal to Execution Interval 
(SP3-515-002) 
4.  Interval: During a Job   
This interrupts printing and then starts automatically if the following condition occurs: 
BW Counter (SP3-510-001) is greater than or equal to Execution Interval 
(SP3-515-003)  
OR  
FC Counter (SP3-510-002) is greater than or equal to Execution Interval 
(SP3-515-004) 
After process control is completed, the machine continues to make prints.  
						

							 
B230/B237 6-10  SM 
5.  In standby mode   
This is done automatically if one of these conditions occurs.   
ƒ a) ΔT is greater than or equal to Temperature Threshold (SP3-531-002: 10°C) 
ƒ b) ΔRH is greater than or equal to Relative Humidity Threshold (SP3-531-003: 
50%RH) 
ƒ c) ΔAH is greater than or equal to Absolute Humidity Threshold (SP3-531-004: 6 
g/m3) 
ƒ  d) Non-use Time is greater than or equal to SP3-531-001 (default: 6 hours) 
It is not done if the machine is in energy saver mode. 
The default non-use time is 6 hours (see condition 4 below), so normally it will only be 
done if the user disables energy saver mode. 
6.  After Toner End Recovery 
This starts after recovery from a toner end condition. 
7.  After Developer Initialization 
Developer initialization occurs automatically in the following conditions: 
ƒ  After a new development unit has been installed 
ƒ  After new developer is installed and 3902-005 to 008 is done, depending on the 
color (see ‘Maintenance’ for details). 
6.2.3 PROCESS CONTROL SELF CHECK PROCEDURE 
 
Step 1: VSG Adjustment 
This machine uses four ID sensors (direct reflection type) for the process control. Each  
						

							 
SM 6-11 B230/B237 
Detailed 
Descriptions 
sensor detects a pattern for each color (see the ‘Printing Process’ section).   
The ID sensor checks the bare transfer belt’s reflectivity. Then the machine calibrates the 
ID sensor until its output when reading the bare transfer belt (known as VSG) is as follows. 
ƒ  VSG = 4.0 ± 0.5 Volts 
This calibration compensates for the transfer belt’s condition and the ID sensor condition. 
For example, dirt on the surface of the belt or ID sensor. 
VSG adjustment is always done during initial process control. But, at other times, it is only 
done if the VSG adjustment counter (SP3-510-007) is more than the value set with 
SP3-511-007 (default: 500) during a job or at job end. 
SC400 is displayed if VSG is out of adjustment range sequentially 3 times. 
SP3-321: Forced VSG Adjustment for each sensor 
SP 3-325: Shows the results of the VSG adjustment (automatic or forced VSG adjustment) 
- 7 digits (Front, Bk, C, Center, M, Y, Rear) 
Step 2: ID Sensor Solid Pattern Generation 
 
First, the machine agitates the developer for between 15 and 30 seconds until the 
fluctuation in TD sensor output becomes less than 0.3V. 
Second, the machine makes the grade patterns (see the diagram). This 10-grade pattern is 
made in black, yellow, cyan, and magenta (40 squares in total).   
ƒ  The machine first makes the first five grades for each color (the first 20 squares), and 
then the second five grades for each color (the remaining 20 squares). 
The patterns are made by changing the development bias and charge roller voltage. The 
difference between development bias and charge roller voltage is always the same. But, 
the development potential changes for each pattern.   
ƒ  The development potential is the difference between the development bias and the 
charge remaining on the drum where the laser writes a black area. The development 
bias changes for each grade, and the charge on black areas of the image is always the 
same, so the development potential also changes. 
Step 3: Sensor Pattern Detection 
The ID sensor measures the light reflected from each grade of the pattern, to detect the 
densities of each grade. This data goes to memory.  
						

							 
B230/B237 6-12  SM 
Step 4: Toner Amount Calculation 
The machine calculates the amount of toner on the transfer belt that is required to make 
each of the 10 grades of the sensor pattern. To do this, the machine uses the output values 
of the ID sensor from each grade of the pattern. 
The amounts of toner are expressed as M/A (mass per unit area, mg/cm
2) 
Step 5: V
D, VB, VL Selection and VTREF Adjustment 
The machine determines the relationship between the amount of toner on the transfer belt 
and the development bias for each of the 10 grades.   
From this, the machine determines the best V
D to get the target M/A for each color. Then, 
based on this V
D, the machine determines the best VB and VL. This process ensures that 
enough toner is deposited to make black pixels. 
The machine also adjusts V
TREF (toner density target) at the same time so that the 
development gamma used by the machine fall within the target development gamma range 
stored in the machine’s software. If it does not fall within this range, the amount of toner 
deposited on the latent image will be too high or too low. 
6.2.4  TONER DENSITY ADJUSTMENT MODE 
If the toner density becomes too high or too low because of an incorrect development 
gamma, this is corrected by process control (see the previous section). But sometimes, it 
takes many copies before the toner density comes to the correct value. 
Toner density adjustment mode can be used to bring the toner concentration to the correct 
level much more quickly, if users complain about the toner density. 
SP 3-043 controls when the toner density adjustment mode is done. 
To do the toner density adjustment mode manually, execute SP 3-011-2. 
It is also done automatically before ACC, if SP3-041-4 is set to 2: TC Control (this is the 
default setting). 
During this procedure, the machine generates ID sensor patterns and detects the current 
development gamma. The gamma must be within ± 0.2 of the target development gamma. 
If the current gamma is too high (above the target by 0.2 or more: 0.2 limit is set with 
SP3-239-009), the machine consumes toner in the development unit until the development 
gamma is within the correct range. To consume toner, the machine generates solid 
patterns. 
If the current gamma is too low (below the target by more than 0.2: 0.2 limit is set with 
SP3-239-012), the machine supplies toner to the development unit until the development 
gamma is within the correct range.