Scanner Unit Here we study the control performed by the scanner motor unit.

Scanner Unit

　

○Purpose: Here we study the control performed by the scanner motor unit.

　

　

1. Outline

The scanner motor unit reflects the laser beams by a revolving polygon mirror, irradiating the beams onto the photosensitive drums.

The scanner motor unit is controlled by the DC controller. When the scanner motor unit receives a drive signal from the DC controller, it drives the scanner motor to turn the polygon mirror.

Below, we explain the part configuration of the scanner motor unit.

1] Scanner Motor Unit

　

[2] Polygon Mirror

　

[3] Scanner Motor

　

[4] SD Circuit Board

　

　

 

-The MAIN CHG signal is used only with the iR3570/4570 models 

(not with the iR2270/2870 models).  

Next, we explain the control performed by the scanner motor unit.

2. Scanner Motor Revolution Control

a. Outline

This control turns the scanner motor with a target number of revolutions (motor speed).

The revolution of the laser scanner motor is driven by a scanner motor acceleration signal (ACC) and a scanner motor deceleration signal (DEC) sent from the DC controller. The number of revolutions of the scanner motor is detected by the scanner motor speed signal (/P FGOUT), which is the feedback signal from the scanner motor unit.

Below we explain the sequence of the scanner motor.

1) When printing begins, the DC controller sends out an ACC signal to accelerate the scanner motor.

2) The DC controller monitors the /P FGOUT signal to check whether the target motor speed has been attained by the scanner motor.

3) Once the scanner motor has reached its target motor speed, the controller sends either an ACC signal or a DEC signal in order to stabilize the number of revolutions of the scanner motor at the target motor speed.

4) When the printing is completed, the DC controller sends a DEC signal to decelerate the scanner motor.

If a printing command is given while the scanner motor is decelerating, the DC controller immediately sends an ACC signal to re-start the scanner motor.

　

　

b. Speed Control

The scanner motor of the iR3570/4570 models is equipped with two speed settings: "High Speed" and "Low Speed."

The switching between these two settings is carried out by a speed-switching signal (MAIN CHG).

When the scanner motor driver receives the MAIN CHG signal from the DC controller, it switches the target speed of the scanner motor.

Because the iR3570/4570 models are equipped with two types of feeding speed (normal speed and low speed), the motor speed of the scanner motor also needs to be switched according to the feeding speed.

3. Failure Detection

This unit also detects any failures of the scanner motor.

Conditions of failure are described below:

a. Conditions of Failure

1) BD Error

Image-formation is enabled (i.e., the scanner motor is operating normally and the laser is emitted), but the cumulative number of times the unit fails to detect BD signal input has reached a certain fixed value.

2) Scanner Motor Failure

∙ The scanner motor is turned on, but its target motor speed is not reached after a certain period of time.

∙ The scanner motor has transitioned to its normal motor speed, but the scanner motor has deviated from its target motor speed for a period of time.

∙ The scanner motor speed has been switched, but the its target motor speed is not reached after a certain period of time.

b.  Measures to Take

1) BD Error

The error message "E100-0000" is shown, disabling the printing.

2) Scanner Motor Failure

The error message "E110-0001," "E110-0002," or "E110-0003" is shown, disabling the printing.

c.  Method of Repair

1) BD Error

If it happens frequently, replace the laser scanner unit or the DC controller.

2) Scanner Motor Failure

Replace the laser scanner unit or the DC controller.