Fault repair for laser printers page 1/2

I. No image repair in the front half of the printer printing page

An HP kserJei laser printer usually displays the first half without an image on the printed page. The latter half is the first half of the original, but the image is normal and not deformed.

Fault phenomenon: it indicates that it is caused by poor backup paper supply. Under normal circumstances, when the paper is rubbed between the top and bottom of the Backup Roller, the backup roller is not in the rotating state, but in a short stop state, after the Controller receives the position signal output by the position sensor on the scanner track, the position roller rotates, and the paper is sent to the rotating drum. The speed of the output paper is equal to the line speed of the rotating drum, the front end of the paper is aligned with the front end of the photosensitive drum image. After being transferred and fixed, a printing page with the same as the original is obtained.

If the speed of the printed paper is equal to the linear speed of the photosensitive drum, the first half of the printed page is blank, no image, and the second half is the first half of the original, and the image is normal, otherwise the image is deformed.

As can be seen from the above, the reason is that there is a problem with the sensor or controller, checking the sensor on the frame next to the scanner track. A sensor is found to be faulty, resulting in forward delivery of paper to the counterpoint roller. After replacing the sensor, the sensor is printed and the fault is rectified.

The scanner advances to the supply side and cannot return to the original position a huipu laser printer. During the continuous printing process, the scanner suddenly advances to the supply side of the printer and cannot return to the original position, the printer made an abnormal noise. The reason why the scanner cannot return the original position is as follows:

(1) poor performance of the returned sensor.
(2) Poor controller performance.
(3) poor contact with the sensor controller is returned.
(4) mechanical faults in the scanner drive system.

According to the fault phenomenon, it occurs suddenly in the continuous printing, accompanied by abnormal sound, so it is suspected that the mechanical part of the scanner drive system is faulty.

Turn on the printer, move the scanner back and forth with your hands, and feel very difficult to move. Under normal circumstances, it is very lightweight to move the scanner with your hands. For this reason, the scanner is pushed back to the original position, boot observation, and the panel display is normal, when the main motor starts to rotate, the scanner also begins to move forward. The exposure light is not bright, and no abnormal "" sound is heard during the scanner's movement. This "" sound is mostly triggered when the scanner enters the end of the track and the rack is touched. Under normal circumstances, when the printer is preheated to a certain temperature, the spindle motor starts to rotate. If the scanner is in the original position, it will remain static. If the scanner is not in the original position, it should immediately return the original position.

Turn on the printer and move the scanner back and forth with your hands for further checks. All the chains are rotated. Normally, when the scanner is mounted, only the drum wheel around the scanner driving the wire rope rotates, the chain does not rotate, so it seems that there is a problem between the drum wheel and the drive sprocket. They are all the driving components of the scanner. The sprocket is located on the inside of the drum wheel. under the action of the clutch, the drive shaft rotates and the drum wheel rotates. After inspection of this part of the removal, it is found that the ball bearing in the wheel has been seriously worn out, the drive shaft is honed out of a slot, the sprocket and the drive shaft are killed, so that when the sprocket starts to rotate, the drive shaft is driven to rotate along with the drum wheel at the same time. This leads to a fault that the scanner can only forward but cannot return.

To completely eliminate faults, replace the New clutch and install other components on the test machine in the original position to restore the operation to normal and rectify the faults.