AL-1456 (serv.man11). Adjustments - Sharp Copying Equipment Service Manual (repair manual). Page 6

AL-1555 ADJUSTMENTS 9 - 6

This step adjusts the front surface printing (odd-number pages of a
document set) in the S-D mode copying and the leading edge position
of an image on even-number pages in the D-S mode.

That is, it covers the adjustment of the second surface printing mode
(image loss at the front edge of an image) in which image data is once
stored in memory.

The image data is read, starting from its front end in the document
delivery direction (Reference direction of document setting in the OC
mode)and stored in memory.

This stored image data is printed starting at the printing start position,
in the order of last-stored data to the first-stored data. 

In other words, the front edge image loss of the image can be adjusted
by changing the document read end position.

1) Preparing test chart (Draw a scale at the rear end of one side of a

sheet of A4 white paper or letter paper)

2) Set the test chart so that the scale is positioned as shown below, in

the S-D mode and the D-S mode.

3) Execute simulation 50-18 to make a copy and check the front edge

image loss at the area where the scale is printed.
Adjust the setting so that the front edge image loss is less than 4.0
mm in the R-SPF mode.
An increase of 1 in setting represents an increase of 0.1 mm in
image loss.

This is the adjustment of the first surface printing mode (rear end void)
in duplex copying.

In a duplex copying operation, the paper is delivered starting from the
rear end of the first printing surface. It is therefore necessary to make a
void area at the rear end on the first printing surface to prevent paper
jam at the fusing part.

There are two adjustment modes:

1) Image cut rear end void quantity (R-SPF) 50-19(AE) 

The size (length) of a document read from the R-SPF is detected,
the image at the trailing edge of the first printing surface is cut to
make a void area. (The adjustment of void quantity at the time
when the cassette paper size is not recognized.)

2) Paper trailing edge void quantity 50-19 (TEXT)

This adjustment is made when the cassette paper size is
recognized. The trailing edge void quantity can be adjusted by
changing the trailing edge image laser OFF timing.

The paper void quantity should be first adjusted before the image cut
trailing edge void quantity (R-SPF) is adjusted.

1) Preparing test chart (Draw a scale at the rear end of one side of a

sheet of A/4 white paper or letter paper)

2) Set the test chart on the document glass as shown below.

3) Using the user simulation [18], set the paper size of the first

cassette. 

• Letter paper: 4

• A4 paper: 3

Scale (S-D mode)

Scale (D-S mode)

5 10

The front edge of the
scale on test chart

 Front edge of paper

Void area

less than 4 mm

2nd printing surface where scale is printed (lower side)

Document guide

The trailing edge has a scale

Table glass