Sharp AR-280 Service Manual page 124

50
50 - 1
Purpose Adjustment
Function Used to adjust the copy image position and the void
(Purpose) area (image loss) on the print paper in the copy mode.
(The same adjustment can be made with SIM 50-2
(simple method).)
Item Picture quality
Operation/ 1. Select the adjustment item with [­] [¯] keys.
Procedure
2. Enter the adjustment value with the 10-key.
3. Press the [OK] key. (The adjustment value entered in procedure 2
is set.)
(RRC-A)
This set value is used to align the document image lead edge ad
the scan image data lead edge in the document table scan mode.
After starting scanning, the image lead edge position is deter-
mined by using the scanner home position detection signal
(MHPS) OFF timing as the reference.
RRC-A set value = Time (distance) from the output of the scanner
home position detection signal (MHPS OFF) to the image lead
edge position.
If this setting is not made properly, the image lead edge position
(image loss) varies depending on the copy magnification ratio.
When the set value is increased, the image position is shifted in
the advancing direction on the paper.
When the set value is changed by 1, the image lead edge position
is varied.
(SPF)
This set value is used to align the document image lead edge po-
sition and the scan image data lead edge position in the SPF scan
mode.
After starting scanning, the scan image lead edge position is de-
termined by using the resist sensor detection signal (REGS ON)
timing as the reference.
RRC-A set value = Time (distance) from the output (resist sensor
detection signal (REGS ON) to the image lead edge position.
If this setting is not made properly, the image lead edge position
(image loss) on the copy paper may vary depending on the copy
magnification ratio.
When the set value is increased, the image position is shifted in
the advancing direction of the copy paper.
When the set value is changed by 1, the image lead edge position
is changed by about 0.1mm.
(RRC-B)
This set value is used to adjust the relative positions of the image
position on the OPC drum and the copy paper.
This adjustment is made by adjusting the time from the output tim-
ing of the image lead edge signal (LD START signal) to RRC ON.
At the timing of LD START signal output, the print image is made
on the OPC drum at an optional position with the laser beam.
Actually the RRC ON timing is determined as follows:
RRC ON timing = This set value (RRC-B) - Lead edge void set
value (DEN-A)
When the set value is increased, the RRC ON timing is delayed,
decreasing the led edge void area.
When the set value is changed by 1, the lead edge void area is
changed by about 0.17mm (about 0.21mm for AR-4XX series;
about 0.24mm for AR-5XX series).
(Note)
The value of RRC-A must be properly set in advance to this ad-
justment.
7/13/2000
Image position
7 – 43
(IMAGE LOSS)
This set value (timing adjustment value) is used to determine the
lead edge image loss and the image lead edge reference position
by using the scan image lead edge position set with RRC-A.
Effective print data is determined from the image lead edge posi-
tion data scanned with this set value.
The image lead edge reference position on the document is at
2mm from the right of the document position alignment plate.
The effective image (effective image data) is determined by scan-
ning the image.
When the set value is increased, the image loss becomes greater.
When the set value is changed by 1, the image loss is changed by
about 0.1mm.
(DEN-A)
Used to set the timing for the RRC ON timing (paper timing) set
with EEC-B.
RRC ON timing = (RRC-B) - Lead edge void set value (DEN-A)
When this adjustment value is changed, the print image position
for the paper position is changed. As a result, the lead edge void
area is also changed.
When the set value is increased, the RRC ON timing is advanced
and the lead edge void area becomes greater.
When the set value is changed by 1, the lead edge void area is
changed by about 0.1mm.
(DEN-B)
The rear edge void area is adjusted by controlling the effective
print data length with the image lead edge signal (LD START sig-
nal) output from the ICU as the reference.
The effective image (effective image data) is determined when
scanning the image.
When the set value is increased, the rear edge void area becomes
great.
When the set value is changed by 1, the rear void area is changed
by about 0.1mm.
(REAR LOSS (SPF))
Used to adjust the rear edge image loss in the SPF copy mode.
The greater the set value is, the greater the rear edge image loss
is.
When the set value is changed by 1, the rear edge image loss is
changed by about 1mm.
Adjust in the following sequence:
1) Set the image loss amount (IMAGE LOSS) and the paper lead
edge void amount (DEN-A) to arbitrary values (20).
(0~99: 0.1mm/step)
2) Adjust the document scan start position (RRC-A) so that the ac-
tual copy image loss becomes the value set in procedure 1. (0~99:
0.24mm/step) (0.29mm/step (AR-405 series))
3) Adjust the resist roller clutch ON timing (RRC-B) so that the actual
copy image loss becomes the value set in procedure 1. (0~99:
0.17mm/step)
4) In the SPF copy mode, adjust the SPF image position (SPF) to the
value set in procedure 1). (0~99, 0.1mm/step)
5) Adjust the rear edge image loss (REAR LOSS (SPF)) in the SPF
copy mode. (0~20, 1mm/step) (AR-2X1/3X1/4XX/250/XX6 series
only)
6) Adjust the rear edge void amount (DEN-B). (0~99: 0.1mm/step)
(AR-250/280/281/285/286/335/336)