Sharp SF-1014 Service Manual page 68

(7) Uniformity adjustment
I. Summary
The uniformity adjustment is performed by changing the ex-
posure plate position attached to No.1 scanner unit.
The above procedure changes the balance of light quantity
radiated onto the document.
II. Purpose
The purpose of this adjustment is to have uniform copy density.
III. Note
When this adjustment is performed, the exposure will be
changed. Therefore, the copy density adjustment must be per-
formed after this adjustment. Also, this adjustment must be per-
formed always before the copy density adjustment.
IV. Cases when the adjustment is required
1) When the reflector is replaced.
2) When the copy lamp is replaced.
3) When the exposure adjustment plate is disassembled or
replaced.
4) In maintenance
V. Necessary tools
* Screwdriver (+)
* A4 or 8 1/2" x 11" paper
* Half-tone paper of A4 or 8 1/2" x 11" or larger
VI. Adjustment procedure
1) Set a half-tone paper of A4 or 8 1/2" x 11" on the document
table.
2) Set the exposure level to the min. level in the photo mode,
and make a copy on A4 or 8 1/2" x 11" paper.
3) Check the uniformity. If there is any unevenness, perform the
following procedures.
4) Move the exposure adjustment plate of the lighter copy sec-
tion towards Y or move the exposure adjustment plate of the
darker copy section towards X.
(Example)
If a copy shown below is made, move the front frame side of
the sub exposure adjustment plate in the direction of X to
adjust the exposure balance.
Paper exit
direction
Half-tone copy
Standard fixing position
Y Y
X X
Exposare adjusting plate
Less exposure
(Dark copy)
[Fig. 1]
Hole
(Center)
Exposare
adjusting plate
Y Y
X X
5) Make a copy in the same manner as procedure 2), and
check the uniformity.
Repeat procedures 1) to 5) until proper uniformity is ob-
tained.
VII. Troubles caused by improper adjustment
(8) Image loss/void area adjustment
The image loss/void area adjustment is performed by the combination
of the copied image position adjustment on the copy paper and the
void area adjustment.
Since the image loss and the void area are closely related each other,
they must be adjusted simultaneously.
(Definitions of image loss and void area)
Void area: Empty (white) area on a copy paper (without toner on it)
Image loss: The quantity (length) of an image lost on a copy paper.
(Document)
(Copy)
Paper lead
edge
a. Copy image position adjustment
I. Summary
In order to adjust the copy image position on a copy paper, the
lead edge position of an image on the photoconductor for the
lead edge position of a document on the document table is
changed with simulations 50-1, and the relative position of the
paper to the image position on the photoconductor is changed.
In the models which have no zoom copy functions, however, the
lead edge position of an image on the photoconductor for the
lead edge position of a document on the document table is not
changed.
The relative position of the paper is changed at OFF timing of
the scanner home position sensor after starting scanning to ad-
just the copy image position on the paper.
After adjusting the copy image position with the above proce-
dure, the M.C grid OFF timing for the lead edge position of an
image on the photoconductor is changed with simulations 45-1
to adjust the void area.
II. Purpose
The purpose of this adjustment is to improve separation in the
photoconductor section and in the fuser section and reduce dirt
on the fuser section pawl by obtaining the max. effective copy
area and the paper void area.
III. Note
If the proper void area is not obtained, the separation ability in
the photoconductor section may be degraded and dirt on the
fuser section pawl may be increased.
Before performing this adjustment, the following adjustments
must have been completed. If not, this adjustment cannot be
performed properly.
* Adjustment of paper pressure against the resist roller
(Sim 51-2 set value must be properly set.)
7 – 18
Li
Li: Lead edge image loss
Lv
Lv: Lead edge void area
(In some cases, Lv > = Lv)