Ricoh B230 Service Manual
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SM 6-43 B230/B237 Detailed Descriptions From Image Transfer Belt Unit The toner collection auger [A] moves the used toner from the image transfer belt and the used toner drops into the toner collection duct [B]. The toner collection coil [C] moves the used toner to the opening [D] at the rear of the toner collection bottle. The toner transport motor [E] drives the toner collection coil. Used Toner Distribution Mechanism The toner collection bottle has two openings (front and rear). The opening at the front is for the toner from the PCUs, and the opening at the rear is for the toner from the image transfer belt. To distribute the toner inside the bottle evenly, the auger [A] moves the toner to the center area. The mixing auger has two spirals in different directions. As a result, it is possible to gather the toner in the center area of the toner collection bottle even if the mixing auger always rotates in the same direction. The toner transport motor [B] drives the mixing auger via a timing belt and gears.
B230/B237 6-44 SM 6.8.2 TONER COLLECTION BOTTLE SET/ NEAR-FULL/ FULL DETECTION The toner collection bottle has a projection at its rear side. When the toner collection bottle is set, this projection pushes the waste toner bottle set switch at the rear of the machine. As a result, the machine detects that the toner collection bottle is installed. The bottle near-full/full detection mechanism is above the bottle. When the used toner pushes up the used toner feeler [A], the waste toner sensor [B] turns off At this time, the machine detects that the toner collection bottle is almost full, and displays a message. After this, when 500 sheets of paper have been copied, the machine detects that the toner collection bottle is full, and the machine stops.
SM 6-45 B230/B237 Detailed Descriptions 6.9 IMAGE TRANSFER AND PAPER SEPARATION 6.9.1 IMAGE TRANSFER Overview 1. Image transfer belt (ITB) 2. ID sensor 3. ITB drive roller 4. Paper transfer roller 5. Rotation encoder 6. Lubricant application roller 7. Toner collection auger 8. Cleaning blade 9. Cleaning roller 10. Image transfer roller The toner is moved from the four drums to the ITB by the four image transfer rollers. This is done with one rotation of the ITB (four toner images are super-imposed onto the belt). The arrow above the C and M drums on the diagram shows the direction of ITB rotation. The ITB drive roller then moves the four-color toner image from the transfer belt to the paper. The paper transfer roller is an idle roller. The cleaning unit in the transfer unit cleans the belt surface with the cleaning blade and roller. The used toner collected from the belt is transported to the toner collection bottle. There are seven ID sensors. Three of them are for the line position adjustment. Four of them are for process control.
B230/B237 6-46 SM ITB (Image Transfer Belt) Drive Drive Motor The ITB drive motor [A] drives the image transfer belt [B] and the cleaning unit via gears and the ITB drive roller [C]. The speed of ITB drive depends on the process line speed (see ‘Laser Exposure – Optical Path’). Transfer belt speed control This machine uses the rotation encoder to control the transfer belt speed. The encoder [A] is on one of the rollers. This encoder checks the rotation speed of the image transfer belt. The controller analyzes the signals from the encoder. Then it adjusts the rotation speed of the image transfer belt. The encoder contains a disk that has 300 notches on its surface [B]. These notches are read by the sensor [C]. The controller counts the number of notches that the sensor has read in the unit of time. If the sensor has read an unusually large number of notches or an unusually small number of notches, the controller ignores such unusual signals. Therefore, incorrect reading does not affect the rotation speed.
SM 6-47 B230/B237 Detailed Descriptions Filter H: The number of notches read by the sensor when the rotation speed of the transfer belt is at its highest possible value. Filter L: The number of notches read by the sensor when the rotation speed of the transfer belt is at its lowest possible value. ITB Current Each image transfer roller [A] applies current to the image transfer belt to attract the toner from each drum [B]. The high voltage supply board supplies current to the image transfer rollers and grounds the belt at roller [C]. The bias that is applied to the image transfer belt is automatically corrected for paper size, temperature (measured by the temperature/humidity sensor at the rear lower right side of the machine). The other rollers are grounded to neutralize the belt surface.
B230/B237 6-48 SM Transfer belt cleaning The ITB-cleaning unit removes toner (during printing) and the ID sensor patterns (during process control or automatic line position adjustment) on the belt. Belt cleaning is completed while the image transfer belt makes one rotation. The ITB drive motor drives the ITB-cleaning unit. The cleaning brush [A] always contacts the image transfer belt [B], and removes used toner from the belt. The cleaning blade [C] in the cleaning unit scrapes the toner off the image transfer belt. Then the toner collection auger [F] transports the toner towards the toner collection duct. The lubricant application roller [D] applies lubricant [E] to the image transfer belt to make toner removal easy. To drive the cleaning unit, the transfer belt rotates gear [G], and gears at the front of the transfer unit drive the auger [F] and the rollers [A, D] in the cleaning unit.
SM 6-49 B230/B237 Detailed Descriptions ITB (Image Transfer Belt) Contact Mechanism The ITB contact and release mechanism increas es the lifetime of the image transfer belt and drums. The drum for black always contacts the belt. But the image transfer belt moves away from the other drums during monochro me printing. In the standby mode, the image transfer belt contacts only the black drum. It moves away from the black drum when you turn the release lever counterclockwise. When the machine prints a color page, the ma chine waits until the previous page has gone through the paper transfer unit. Then the ITB contact motor [A] turns on and a cam [B] moves the left side [C] of the image transfer bel t downward, so that it contacts the other three drums. The machine does not release t he image transfer belt from the color drums during the job, even if a monochrome page comes again. This is because the total printing speed reduces if the ITB changes position. But, if you change SP 2907 003 away from the default setting of zero, the image transfer belt will move away from the color drums if the number of consecutive black-and-white pr ints reaches the value of SP 2907 003. The belt moves away from the color drums if the job is inte rrupted by any error except a power failure. The image transfer belt contact sensor [D] detec ts if the image transfer belt contacts the color PCUs. ƒ If a power failure occurs when the image transfe r belt is in contact with the drums, the belt stays in this position. If you want to remove the image transfer belt unit while the power is still off, you must release the belt. To do this, swing out the controller box and perform the following procedure: ⇒ Rev. 09/2006
B230/B237 6-50 SM 1. Remove the Image Transfer Belt Contact Motor [A] ( sec. 3.10.8). 2. Using needle nose pliers, turn the Transfer Belt Contact Motor Shaft [B] until the flat surface of the shaft is facing up . 3. Open the front cover of the machine and ens ure the Transfer Belt is away from the OPC units before removing. 4. To reinstall the Transfer Belt Contact Mo tor, first turn the shaft [B] until the flat surface is facing down . 5. Reinstall the Transfer Belt Contact Motor. Transfer Belt Sensor The ITB contact sensor [D] oper ates as the detection sensor during machine initialization, and also as the position sensor during machine operations. Before machine initialization, t he left side of the image transfer belt is in the home position. When initialization starts, the IT B contact motor lowers the left side until the actuator has passed the sensor. Then ITB contact motor lifts up the left side to its home position. This action actuates t he sensor in a certain pattern. The table lists the sens or actuation patterns. Machine status Sensor pattern Initialization On Off On Off On Standby (Default) On B/W printing On Operation Color Printing Off On: The actuator is out of the sensor. Off: The actuator is interrupting the sensor. [B] [A] ⇒ Rev. 09/2006
SM 6-51 B230/B237 Detailed Descriptions 6.9.2 PAPER TRANSFER AND SEPARATION Overview 1. Paper transfer roller 2. Discharge plate 3. ITB drive roller 4. Image transfer roller 5. Image transfer belt 6. OPC drum The paper transfer unit consists of the paper transfer roller and discharge plate. This unit completes the toner transfer to the paper. PTR (Paper Transfer Roller) Drive ƒ P.P.: Power Pack
B230/B237 6-52 SM The toner is moved from the OPC [A] onto the surface of the image transfer belt [B] by a positive charge from the image transfer roller (immediately above the drum, not shown here). The ITB drive roller [C], which is given a negative charge, pushes the toner to the paper [D]. The paper transfer roller [E] presses the paper against the image transfer belt [B] (with a spring that is under tension from the paper transfer roller contact motor), and grounds the charge from the ITB drive roller [C]. (The paper transfer roller does not have a drive mechanism. This roller is driven by the image transfer belt.) Finally, the discharge plate [E], which is given an AC charge, discharges the paper. The discharge plate receives its charge from a different high voltage power supply board than the ITB drive roller. PTR (Paper Transfer Roller) Contact and Separation The paper transfer contact motor [A] keeps the paper transfer roller [B] in contact with the image transfer belt [C]. This motor has the paper transfer HP sensor [D] inside. The paper transfer HP sensor detects if the paper transfer roller is in contact with the image transfer belt. Only when the machine executes the line position adjustment or process control, the