Ricoh Mp C3000 Service Manual

							 
SM 6-11 B230/B237/D042 
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 fo r the transfer belt’s condition and the ID sensor condition. 
For example, dirt on the surfac e of the belt or ID sensor. 
VSG adjustment is always done during initial proces s 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 Adjust ment for each sensor 
SP 3-325: Shows the results of the VSG adjus tment (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 develo per for between 15 and 30 seconds until the 
fluctuation in TD sensor out put 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 gr ades 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 developm ent 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 la ser 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/D042 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 betw een 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 t he same time so that the 
development gamma used by the machine fall wi thin 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 w ill 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 (s ee the previous section). But sometimes, it 
takes many copies before the toner d ensity 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 pa tterns 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 c onsume toner, the machine generates solid 
patterns. 
If the current gamma is too low (below the tar get 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.    
						

							 
SM 6-13 B230/B237/D042 
Detailed 
Descriptions 
6.2.5  TONER SUPPLY CONTROL 
Overview 
Toner supply control determines  how long the toner supply clutch turns on. This determines 
the amount of toner supplied.  This is done before every development for each color. 
Toner supply control uses  the following factors: 
ƒ  Density of the toner in the develo per (detected by the TD sensor) - V
REF, VT 
ƒ  Pixel count: Determines how much toner was used for the page 
The image density is kept constant by adjusti ng the density of toner in the development unit. 
At the same time, it accommodates changes  in the development conditions through the 
potential control mechanism. Environmental  changes and the number of prints made are 
also used in the calculation. 
The amount of toner supplied is  determined by the ‘on’ time of the toner supply clutch. The 
total ‘on’ time for each toner supply clutch is  stored in the memory chip for the relevant 
toner cartridge. The machine supplies the calculated amount of toner for each color. 
The machine automatically changes the toner supply mode to  fixed supply mode if the TD 
sensor is broken. However,  the supply amount will be 70% of  the normal fixed value to 
prevent too high image density. 
The machine automatically  changes the toner supply mode  to PID control mode (Fixed 
Vtref) if the ID sensors are broken. 
Toner Supply Control Modes 
This machine has three toner supply control  modes. You can select them with SP3-044-1 
to -4. 
1.  Fixed supply mode  This mode is used when the TD  sensor becomes faulty. You can adjust the amount of 
toner supply with SP3-401-1 to -4 if the im age density is incorrect (the default setting is 
5%). 
2.  PID (Proportional Integral Diff erential) control mode (Fixed V
TREF) 
This mode is used when the ID  sensor becomes faulty. Only the TD sensor is used to 
control toner supply. The mach ine uses the VTREF that is stored in SP3-222-1 to -4. 
3.  Fuzzy control mode    This is the default toner  supply control mode. The TD  sensor, ID sensor, and pixel 
count are used in this mode. V
TREF is adjusted by process control. 
⇒ 
Rev. 03/2007 
						

							 
B230/B237/D042 6-14 SM 
6.2.6 TONER NEAR END/TONER END DETECTION 
 
Toner Near End  
The controller considers the following inform ation to determine the toner near end status: 
ƒ  Operation time counter of  the toner attraction pump [A] 
ƒ Pixel counter  
These values are both stored in the memory  chip [B] on the toner cartridge, and copied 
from the memory chip to the NVRAM on the BICU.   
If either value indicates that the amount of  remaining toner is 50g or less, the machine 
enters the near-end condition. 
Toner End  
To determine the toner end stat us, the machine uses the TD sensor [C] in the development 
unit. The machine must first be in a toner  near-end condition, or toner end cannot be 
detected. 
Toner end is detected if both the following conditions occurs: 
ƒ V
T – VTREF greater than or equal to 0.5 (SP3-101-021) 
ƒ SUM (V
T – VTREF) greater than or equal to 10 (SP3-101-026) 
The machine cannot print until the toner cartridge  is replaced after it detects toner end for 
black. The machine can print in black and whit e only if cyan, magenta, or yellow are in a 
toner end condition during standby mode. At this  time the machine cannot do color print 
jobs. 
 
ƒ  If the yellow, cyan, or magenta toner ends during a color-printing job, the job is 
suspended until toner is supplied. If new colo r toner is not installed, the user can  
						

							 
SM 6-15 B230/B237/D042 
Detailed 
Descriptions 
print black-and-white jobs only. 
Toner End Recovery  
The machine assumes that the toner cartridge has been replaced if either of the following 
occurs when the near-end or end status exists: 
ƒ  The front door is opened and closed. 
ƒ  The main switch is turned off and on. 
Then the machine starts to supply toner to  the development unit. After supplying toner, the 
machine clears the toner near-end or end status  if the following condition is detected: 
ƒ  Toner end sensor detects  that toner is supplied. 
The machine tries to supply toner fo r a maximum of 5 times (SP 3-102). 
6.2.7 DEVELOPER INITIALIZATION 
When is it done? 
When you install new developer, you must set the following SPs to 1 before you turn the 
power off. Then, the machine will reset t he PM counters automatically. Developer 
initialization will also be done automatically. 
ƒ Black: SP3902-005 
ƒ Yellow: SP3902-006 
ƒ Cyan: SP3902-007 
ƒ Magenta: SP3902-008 
When a new development unit or PCU is inst alled, the machine detects the new unit 
automatically and initia lizes the developer. 
How is it done?  
The procedure is as follows. 
1.  The machine agitates the developer for 30 seconds. 
2.  The machine adjusts V
CNT (control voltage for TD sensor) so that VT (TD sensor output) 
becomes within 2.7 ± 0.2. 
3.  The machine keeps this as V
TREF if it is successful. SC372 to SC375 is displayed if it 
fails sequentially 3 times. 
The result of developer initializat ion can be checked with SP3-014.   
 
During developer initialization, the machine  forcibly supplies toner because there is no 
toner inside the toner transport tube at inst allation. Then the machine does the process 
control self check. 
⇒
Rev. 03/2007 
						

							 
B230/B237/D042 6-16 SM 
6.3 SCANNING 
6.3.1 OVERVIEW 
 
 
1. Scanner HP sensor 
2. ADF exposure glass 
3. 2nd scanner (2nd carriage) 
4. Scanner lamp 
5. 1st scanner (1st carriage)  6. Exposure glass 
7. Scanner motor 
8. Sensor board unit (SBU) 
9. Lens Block 
10. Original length sensor 
11. Original width sensor 
 
The original on the exposure glass or ARDF ex
posure glass reflects the light emitted from 
the scanner lamp. The reflected light goes to  the CCD on the sensor board by way of the 
1st and 2nd scanners. The sensor board conv erts the CCD analog signals into digital 
signals. 
When the original is manually placed on the ex posure glass, the scanner motor pulls the 
1st and 2nd scanners via mechanical linkage. The original is scanned from left to right. 
When the original is fed from the optional A RDF, it is automatically transported onto the 
ARDF exposure glass, and to the original exit.  The original does not stay on the glass; but 
goes to the exit. The 1st and 2nd scanners stay at their home positions.  
						

							 
SM 6-17 B230/B237/D042 
Detailed 
Descriptions 
6.3.2 SCANNER DRIVE 
 
The scanner motor [A] drives the 1st sc anner [B] and the 2nd scanner [C] through the 
scanner drive pulley, scanner drive shaft [D], and two scanner wires [E]. 
Book mode -  
The SBU board controls the scanner drive motor.  The 2nd scanner speed is half that of the 
1st scanner. 
In reduction or enlargement m ode, the scanning speed depends on  the magnification ratio. 
The returning speed is always the same, whet her in full size or magnification mode. The 
image length change in the sub  scan direction is done by changing the scanner motor 
speed. In the main scan direction it is  done by image processing on the BICU board. 
You can adjust the magnification in the sub-scan direction by changing the scanner motor 
speed with SP4-008. 
ARDF mode -  
The scanners always stay in their home position (the scanner HP sensor  [F] detects the 1st 
scanner) to scan the original. The ARDF moto r feeds the original through the ARDF. In 
reduction/enlargement mode, the  image length change in the sub-scan direction is done by 
changing the ARDF motor speed. Magnification in  the main scan direction is done in the 
BICU board. This is the  same as for book mode. 
You can adjust magnification in the sub-scan  direction by changing the ARDF motor speed 
with SP6-017.  
						

							 
B230/B237/D042 6-18 SM 
6.3.3  ORIGINAL SIZE DETECTION 
 
ƒ  The original width sensors [A] detect the orig inal width. The original length sensors [B] 
detect the original length. 
ƒ  The SBU controller on the SBU board checks each sensor stat us when the platen 
cover sensor [C] is activated as  it is closed. It detects the original size by the on/off 
signals it gets from each sensor. 
ƒ  If the copy is made with the platen cove r fully open, the SBU controller on the SBU 
determines the original size from the sensor  outputs after the Start key is pressed.   
 
Original Size   Length Sensor Width 
Sensor 
Metric version  Inch version  L3  L2  L1  W1 W2   SP4-301
 
display  
A3  11 x 17  O  O  O  O  O  00011111 
B4 10 x 14  O  O  O  O  X  00011110  
						

							 
SM 6-19 B230/B237/D042 
Detailed 
Descriptions 
F4 
8.5 x 13, 8.25 x  13, or 8 x 13 
SP 5126 controls the  size that is detected  8.5” x 14”  O  O  O  X  X  00011100 
A4 LEF  8.5 x 11  X  X  X  O  O  00000011 
B5 LEF 
-  X  X  X  O  X  00000010 
A4 SEF  11 x 8.5  X  O  O  X  X  00001100 
B5 SEF  -  X  X  O  X  X  00000100 
A5 LEF/ SEF 5.5 x 8.5, 
8.5 x 5.5  X X X X X 00000000 
 
ƒ  O: Paper present, X: Paper not present 
The above table shows the outputs  of the sensors for each original size. This original size 
detection method eliminates t he necessity for a pre-scan and increases the machine’s 
productivity. 
However, if the by-pass tray is used, t he machine assumes that the copy paper is 
lengthwise (L). For example, if A4 sideways paper is placed on the by-pass tray, the 
machine assumes it is A3 paper and scans a full  A3 area. Information from the original size 
sensors is disregarded. 
Refer to the ARDF manual for more informat ion on original size detection with the ARDF. 
6.3.4 ANTI-CONDENSATION HEATER 
The anti-condensation heater is available as an optional unit. The anti-condensation heater 
prevents condensation on the mirrors. Condensation can occur w hen the scanner unit is, 
for example, moved from a cold room to  a warm room. Condensation can cause abnormal 
images.  
						

							 
B230/B237/D042 6-20 SM 
6.4 IMAGE PROCESSING 
6.4.1 OVERVIEW 
 
6.4.2  SBU (SENSOR BOARD UNIT) 
SBU 
The VPU (Video Processor Unit ) does the following functions: 
ƒ Black level correction 
ƒ  White level correction 
ƒ Gradation calibration 
ƒ  ADS control (Background Density) 
ƒ  Creating the SBU test pattern 
Operation Summary  
The signals from the 3-line CCD, one line for each color (R, G, B) and 2 analog signals per 
line (ODD, EVEN), are sampled by the ASIC and  converted to digital signals in the 10-bit 
A/D converter. This is the  first phase of processing the  data scanned from the original. 
Storing Operation Settings  
The controller stores the SBU se ttings. These values must be restored after the lens block 
is replaced: