AL-840 (serv.man6). AL800 840 Service Manual-Adjustments - Sharp Copying Equipment Service Manual (repair manual). Page 12

Adjustment item

Adjustment

mode display

(Lighting)

Note

Image lead edge
position (Print
start position)

Auto copy mode
lamp

Used to determine the positions of
paper and images. The paper lead
edge is aligned with the document
lead edge reference position (image
lead edge).
(Corresponds to the time from
detection og the paper lead edge by
PIN detector to print start (scanner
start). 

Image lead edge
reference
position (Image
scannign start
position)

Photo copy
mode lamp

Used to determine the image lead
edge reference position. (Used to
determine the distance from the
scanner home position to the
document lead edge refrence
position.)

Lead edge void
area (Image loss)

Manual copy
mode lamp

Used to adjust the lead edge section
effective image amount, 
The image amount scanned until the
scanner reaches the image lead edge
reference position after start scanning
and the image amount scanned
during the time corresponding to this
setting are cut (made invlaid) to form
the image loss and the void area. 

Rear edge void
area

Auto/Photo/
Manual copy
mode lamp

Used to determine the print image
(data) cut timing.
The PIN detector detects the paper
length.
The print image (data) cut timing is
determined from the detected paper
length and the sub scanning direction
image length. 

1) Enter the SIM 50-1 mode.

2) Select the adjustment mode image lead edge position (print start

position) with the copy picture quality mode select key. 

(The currently set adjustment value is displayed on the copy
quantity display.)

3) Set  the value to  "50" and press the start button.

(the adjustment value is stored and a copy is made.)

When the set value is increased, the image lead edge position is
shifted forward for the paper lead edge position.

When the set value is decreased, the image lead edge position is
shifted backward for the paper lead edge position.

4) Place the scale at the document table lead edge reference in the

sub scanning direction, and place a white paper (A4, 11" 

×

 8.5") at

a slightely shifted position to the right of the scale. 

5) Select the adjustment mode image lead edge reference position

(image scan start position) with the copy picture quality mode
select key. 

(The currently set adjustment value is displayed on the copy
quantity display.)

6) Press the start button. (Make a copy with the document cover

open.)

(A copy is made.)

7) Measure the distance between the paper lead edge position and

the copy image lead edge reference position (scale image lead
edge).
If the scale image is cut halfway, assume the virtual lead edge of
the scale image for measurement.

If the distance between the paper lead edge and the image lead
edge is not 0 

±

 1.5mm, change the set value and press the start

button.

(the adjustment value is stored and a copy is made.)

When the set value is increased, the image lead edge position is
shifted forward for the paper lead edge position.
When the set value is decreased, the image lead edge position is
shifted backward for the paper lead edge position.

(Note)

If this adjustment value is improper, the copy image lead edge
position varies when the copy magnification ratio is chanfed. 

8) Select the adjustment mode lead edge void area (image loss) with

the copy picture quality mode select key. 

(The currently set adjustment value is displayed on the copy
quantity display.)

9) Press the start button. 

(A copy is made.)

10) Measure the lead edge void area (image loss). 

If the distance between the paper lead edge and the copy image
lead edge is not 2.5

±

15mm, change the set value and press the

start button. 

Scale

Allow a clearance.

White paper

(A4, 11" x 8.5")

10

20

30

40

50

0mm

Paper lead edge

Image lead edge

Copy scale image

10

20

30

40

50

2.5mm

Void area

Paper lead edge

Copy scale image

Image loss

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