Sharp SF-1120, SF-1020 service manual End of scale image

(4)Measure the distance between the copy paper lead edge and the copy image lead edge in each copy. Obtain RRC-A and RRC-B values from the following formulas.

If the RRC-A preset value is not proper, the lead edge position varies in each magnification ratio. The RRC-B is to adjust the RRC ON timing for fitting the drum image lead edge and the transfer paper lead edge.

(8)Put a scale and an A3 (11" × 17") white paper on the original table as shown below.

L2

10 20 30 40 50 60 70

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L1

10 20 30

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									Scale
10	20	30 40	50	60	70	80	90	50	100 110 12 0130 140
				50mm
									A3(11" x 17") Blank paper

Full-size(100%) copy Enlarged(200%) copy

•La: Led edge shift at 200% (mm)

•L2: Lead edge shift at 1005 (mm)

•RRC-A = 6.151 × (L1 – L2)

•RRC-B = 15.385 × L2 – 7.692 × L1

(5)Enter the RRC-A and RRC-B values obtained from the above formulas with the 10 digit key pad in the same manner as procedure (3).

(6)Make copies at 200%, 100%, and 50%, and check variations in the magnification ratios. (About 1.0mm)

If there is a considerable variation, repeat from procedure (3).

(7)Make a normal copy and check that the lead edge image loss is within the range of 0 ∼ 4mm. If the image loss is outside the above range, change the RRC-B value and adjust again until the image loss is within the above range.

10 20 30 40 50 60 70

Image loss	Full-size(100%) copy
0~4mm

Note: The above image loss range is effective only for simulation 50-01, and is not the final one.

(9)Press the zoom key to display "C" in the lowest digit of the magnification ratio display. (Void amount adjustment mode)

(10)Make a copy and enter the normal copy lead edge void area adjustment set value so that the black background edge comes to the scale 1 – 3mm of the copy image scale.

→ → PSW

With the above key operation, a copy is made and the adjust- ment value is inputted. When the adjustment value is changed by 1, the void area is changed by about 0.13mm. The greater the adjustment value is, the greater the void amount is.

End void area 1~3mm

Scale image

10 20 30 40 50

Solid edge

Paper end

Full-size(100%) copy

7 – 14