Ricoh Mp C3000 Service Manual
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![Page 826
B230/B237/D042 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. Ea ch 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...](http://img.usermanuals.tech/thumb/64/98663/w64_mp-c3000-service-manual-1509271621_d-825.png "Page 826
B230/B237/D042 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. Ea ch 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...")
![Page 834
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...](http://img.usermanuals.tech/thumb/64/98663/w64_mp-c3000-service-manual-1509271621_d-833.png "Page 834
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...")
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: