Dirt Avoidance Control To avoid dirt from being on an image in ADF mode

Dirt Avoidance Control

a. Overview

The machine controls so that any dirt will not be on an image in ADF mode.
If dirt exists on the stream reading glass of the reader unit, it is read out during document reading from the ADF. As such, the machine detects dirt on the glass, and if any, it changes an original reading position and/or corrects an image to avoid dirt.

　

b. Control Timing

The control is performed under any of the following conditions in ADF mode while the ADF is closed.

∙When a job is started. (Any of the following conditions must be satisfied.)

     / The first job after the power is on.

     / Dirt was detected in all detection points when the previous job was ended

     / Dirt detection was not properly ended when the previous job was ended. (Due to open of the ADF, etc.)

∙When a job is ended.

∙Between sheets (every time a sheet is read)

　

c. Detail of Control

The machine first detects dirt at the 3 original reading points (A, B, C). The CIS gives off the LED at each point, and detects the reflected light from the ADF platen roller surface to judge presence/absence of dirt. If dirt exists, the reader controller executes the following operations to avoid dirt.

∙Read an image to avoid the point where dirt has been detected.

∙Correct image including dirt.

　

Details of the dirt avoidance control on a control-timing basis are shown below.

　

1) When a job is started.

Detection of dirt at the points A, B, and C. The CIS is moved to the least dirt point to read image.

2) When a job is ended.

Detection of dirt at the points A, B, and C. The least dirt point is determined as a reading position of the next job.

3) Between sheets

Original is read at a specific position when a job is started/ended. If dirt is detected in the position, the reader controller executes image correction. (The CIS does not move from the determined point.)

Position	Detail
A	Reading standard position
B	Approx. 0.5mm toward the inside roller from the standard position
C	Approx. 1.0mm toward the inside roller from the standard position

If dirt is detected at the all points when a job is ended, and an original is set to the ADF thereafter, the message inducing user to clean the glass [Original scanning area (thin glass strip) is dirty.] is displayed on the control panel.

In this case, clean the ADF original reading glass to remove dirt. (See [Service Tasks] for the cleaning procedure.)

You can use the ADF to read images or make prints even while this message is indicated.