SHARP DTE319 Technical Report

DUPLICATOR : SD-4085

Date

:

Nov. 14, 1997

No. : DTE-319

ADJUSTING FOR TEXT BLURRING DUE TO DROP IN RDH
UNIT TRANSPORT PRESSURE.

1.Model Name: SD-4085

2.General: This report discusses how to adjust for text blurring caused by the RDH (drop in

exposure roller transport pressure) and should be used by maintenance personnel.
This kind of problem is thought to be extremely rare in copiers on the market, but if it
does occur, repair it using the methods described below.

(Note)
This method deals with text blurring (due to a drop in exposure roller transport pressure)
and will not be effective for other imaging problems due to other causes.

SHARP CORPORATION Reprography Division

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Green

C

1 Cause of the problem

The exposure rollers are made of a mix of rubber and granular plastic, and depending
on how long they are used, the coefficient of friction on the roller surface can change
slightly. Usually, cleaning the rollers with alcohol and removing any foreign particles
should return them to their original condition, but if the rubber is worn and too much
granular plastic appears on the surface, there may be problems with a drop in original
transport pressure. This usually appears as blurring on the front edges of original
images, particularly on the first exposure.

2 Solution

You can return the rollers to their original condition by removing the plastic from the
roller surface with a metal file and cleaning with alcohol. However, you must be
careful not to alter the diameter of the rollers or make them off-center.

(Using something finer, such as sandpaper, may be harmful.)
(Use a commercially available coarse metal file.)

Method

1. Clean the rollers and check that there is no more blurring using a magnification
equalizer (Sim 48-1).

(Check with the C-3 chart, D-D mode)

2. Open the RDH upper unit and rotate the exposure rollers using Sim 2-3-9.
(If you don’t turn on the upper unit F side check RCSW1, the rollers won’t rotate.)

3. While the rollers are rotating, lightly press the metal file against the two exposure
rollers for 20 ~ 30 seconds and file.

Metal file

No.2 exposure roller

Metal file

No.1 exposure roller

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Diagonal lines indicate areas on No.1 and No.2 rollers which must be filed