Ricoh Mp C3000 Service Manual

							 
SM 6-31 B230/B237/D042 
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. Theref
ore, four color developments are possible 
during one paper path. This improves the pr oductivity 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 asse mbled as a PCU at the factory.   
The ID chip is part of the TD sensor asse mbly. 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 t he drum unit is not kept on the new ID chip.  
						

							 
B230/B237/D042 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 dr um 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. Th is 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 mo tor 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 bl ack [C] and magenta [D] drum gears. The drum 
gear position sensors [E][F] det ect 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 gea rs are adjusted every 30 jobs.    
						

							 
SM 6-33 B230/B237/D042 
Detailed 
Descriptions 
Drum Charge and Quenching 
 
This machine uses a non-contact charge ro ller [A] to reduce ozone. The non-contact 
charge roller gives the drum surface a negativ e charge. The high voltage supply board – 
C.B, which is located at the rear of the ma chine, applies a dc and ac voltage (at a constant 
current) to the roller. The ac voltage helps to ens ure that the charge given to the drum is as 
uniform as possible. 
The machine automatically contro ls the charge roller voltage if automatic process control is 
enabled (i.e., if SP3-041-1 is set to CONTROL) . However, if process control is switched 
off, (i.e., if SP3-041-1 is set  to FIXED), the dc voltage is the value stored in SP2-001-1 to 
-12 (do not adjust in the field unless advised to do so).   
The diameter of the charge roller is 12.5 mm (circumference about 39.3 mm). The gap 
between a drum and the corresponding charge roller is about 50  μm. 
The cleaning roller [B], which always contacts  the charge roller, cleans the charge roller. 
Quenching is done by illuminating t he whole area of the drum with the laser at the end of 
every job.  
						

							 
B230/B237/D042 6-34 SM 
Drum Cleaning 
 
The cleaning blade [A] scrapes off the used t oner that stays on the drum. The toner 
collection auger [B] transports the used toner  towards the toner collection duct. Then it 
goes to the toner collection duct. The brush ro ller [C] put lubricant on the drum to make 
toner removal easy the next time the drum rotates past the cleaning blade.   
If the temperature is above the va lue of SP 3517, the drum reverses briefly at the end of the 
job to prevent the blade from flipping over. 
The brush roller rubs against the lubricant  bar [D] and lubricates the drum surface. 
Lubricant is uniformly applied on  the surface of the drum by the lubricant application blade 
[E].  
The toner collection auger [B] in each PCU is  driven by gears [F] at the end of the drum. 
This toner then goes to the toner collection  bottle (see section Toner Collection Path and 
Drive in this section).    
						

							 
SM 6-35 B230/B237/D042 
Detailed 
Descriptions 
6.6.3 DEVELOPMENT 
Development Operation 
 
This machine uses a dual-c omponent development system and  has four development units 
(which are included in the drum units), one  for each color. Each contains 225 g of 
developer when it is new. The developer in each  unit is supplied to the development roller 
[A] by the two mixing augers [B] and attrac ted onto the surface of its roller.   
The TD sensor [C] in the development unit and  four ID sensors above the ITB control toner 
density. Each development unit has a TD sensor. The TD sensor contains an ID chip in 
which some information about the development unit is stored. 
The diameter of the development roller  is 18 mm (circumference about 56.5 mm).  
						

							 
B230/B237/D042 6-36 SM 
Drive 
 
The drum/development drive motor-K [A] driv es the development roller for black through 
gears and a clutch. The gear trains  are shown in the diagram. 
The development drive motor-CMY [B] drives  the development unit for magenta, cyan, and 
yellow through gears.   
Developer Agitation 
 
Two mixing augers [A] circulate the devel oper forward and backward to agitate the 
developer. 
This happens at the following times: 
ƒ  During process control self check 
ƒ During toner supply  
						

							 
SM 6-37 B230/B237/D042 
Detailed 
Descriptions 
ƒ During development. 
Filters [B] on the top of the developer hopper make  sure that the internal pressure does not 
become too high. These  ducts are sealed not to let the t oner solidify before installing.   
This development unit does not operate well if  it placed in a condition of over 50°C during 
transportation. The toner inside the developmen t unit can become solid at temperatures 
higher than this value. A developer initialization error shows if the toner does become solid. 
At this time, you must do the following procedure: 
 
ƒ  You should also do this procedure when you install a new development unit. 
1.  Remove the (old) development unit. 
2.  Keep the (new) development uni t level and shake it several times from side to side.   
3.  Install it in the machine. 
Development Bias 
The PSU supplies development bias to the development roller via the receptacle at the rear 
of each development unit. 
There is a dc bias voltage. 
The machine automatically contro ls the dc bias if the automatic process control is enabled 
(i.e., if SP3-041-001 is set to 1: ON). However,  if process control is switched off, (i.e., if 
SP3-041-001 is set to 0: OFF), the dc bias is  the value stored in SP3-621-001 to -012 (do 
not adjust in the field unless advised to do so).   
New Unit Detection 
 
The TD sensor [A] in the development unit has an ID chip that contains the new unit 
detection flag. The machine detects  that a PCU is new if the flag in the ID chip is activated.  
						

							 
B230/B237/D042 6-38 SM 
The machine automatically does the following adjustments when detecting the new unit 
detection flag. 
ƒ  PM counter clear for items related to the PCU 
ƒ Developer initialization 
ƒ  Charge roller voltage control 
ƒ Process control 
ƒ  Line position adjustment 
If the PM counter clear fails,  clear the following SPs manually. 
ƒ  SP3-902-1 to -4   
ƒ  SP3-902-5 to -8 
ƒ  SP3-902-9 to -12 
6.7 TONER SUPPLY 
6.7.1 OVERVIEW 
 
 
1. Toner bottle (each color) 
2. Memory chip (each color) 
3. Toner end sensor (each color)  4. Toner attraction pump (each color) 
5. Development unit (each color) 
6. TD sensor (each color) 
 
This machine uses four toner bottles. Each bo
ttle has a spiral groove in it and its groove 
moves toner to the toner attraction pump. A nd the toner attraction pump transports the  
						

							 
SM 6-39 B230/B237/D042 
Detailed 
Descriptions 
toner to the development unit. 
The toner end sensor is atta ched to the toner supply tube.  The toner end sensor and the 
output from the process control defi ne when the machine detects toner end. 
6.7.2  TONER SUPPLY MECHANISM 
Toner supply from toner bottle to toner attraction pump 
 
The toner transport motor [A] rotates the toner bottle-Bk via gears and a clutch. It also 
rotates the toner bottle-Y, -C, -M via gears, clutches and timing belts.   
Each bottle has a spiral groove, and this groove  moves toner to the mouth [B] of the bottle. 
Here, toner spills into a hopper [C]. The opening  [D] of the toner hopper is normally closed 
if the toner bottle is not installed in the mach ine. When the toner bottle is installed in the 
machine, the transport tube [E ] pushes the toner hopper shutter [F] and then the opening of 
the toner hopper is open.   
The toner passes part of the way along the  transport tube towards the toner attraction 
pump. The toner goes through  the toner end sensor [G].   
Toner Near End Detection 
The toner end sensors [G] detect toner near end conditions (  Toner Near End/Toner 
End Detection in this section).  
						

							 
B230/B237/D042 6-40 SM 
Toner supply from toner attraction pump to development unit 
 
Each toner attraction pump [A] is driven by  the toner transport motor [B]. Each toner 
attraction pump has the same mechanism.  The pump (toner attraction pump) has the 
following components:   
ƒ  Toner supply clutch [C] 
ƒ Rubber tube  
ƒ Rotor [D] 
The above components attract the toner in the toner transport tube [E] toward the 
development unit. 
The toner supply clutch controls the rotor, which draws the toner in from the cartridge and 
passes it to the development unit. When suppl ying toner, the clutch turns on and off as 
many times as necessary to supply the nece ssary amount of toner. The amount of toner 
depends on the results of  toner supply control. 
Shutter Mechanism 
The development unit and toner attraction pump each have a shutter mechanism. The 
shutter [F] on the pump opens when the development unit is plac ed in the machine. At the 
same time, the pump opens the shutter [G]  in the development unit. When both shutters 
are open, toner can enter the development unit from the toner attraction pump. 
The shutter springs pull and close the shutte r when the development unit is removed.