SHARP SP1938 Technical Report

Date: Oct. 3, 1995

COPIER : SF-2050

1. MEASURE TO PREVENT THE VFM RELAY HARNESS FROM COMING IN
CONTACT WITH THE FAN MOTOR.

2. MEASURE TO PREVENT DETECTION ERRORS OF THE COPY PAPER
DETECTION SENSOR IN THE 500 TRA Y PAPER FEEDER UNIT.

3. MEASURE TO IMPROVE GRID BIAS VOLTAGE FLUCTUATION CONDITIONS.

No. : SP-1938

1. Measure to prevent the VFM relay harness from coming in contact with the fan
motor.

1.Model name: SF-2050.

2.General: There was a danger of the VFM relay harness, which runs along the top of the joint

plate, coming in contact with the fan motor. To alleviate this problem, a wire band was
passed through the cut-away sections in the metal of the joint plate to secure the relay
harness.

Section of the harness
wound with tape.

Wire band.

Joint plate.

3.Action: From the start of 1995 July production.

SHARP CORPORATION Reprography Division

1/3

Green

C

2. Measure to prevent detection errors of the copy paper detection sensor in the 500
tray paper feeder unit.

1.Model name: SF-2050.

2.General: If the copy paper in the tray should for some reason bend

or curl as shown in the diagram to the right, the copy
paper detection sensor registers a “paper empty”
detection signal, even though there is still copy paper
remaining in the tray. This problem has been alleviated by
lengthening the paper detection sensor lever.

Only the left side has been changed.

ONOFF

3.Action: From the start of 1995 August production.

3. Measure to improve grid bias voltage fluctuation conditions.

1.Model name: SF-2050.

2.General: Fluctuations in the grid bias voltage occur when process control adjustments are

carried out and the optical mode is changed. To improve the fluctuation conditions, the
resistance employed in the high voltage unit has been changed. Furthermore, a
capacitor has been added in the high voltage unit in the 200 V line to improve problems
of abnormal noise.

3.Description: (1) Change in resistance: 9.1 kΩ → 6.8 kΩ (R418).
(2) Addition of capacitor: A capacitor (22000 PF) has been added between the

1 pin and the 3 pin of the HIC (MC201).
Note: The changes described above have been carried out solely as improvement
measures. As a result, actions such as the establishment of service parts, changes in
high voltage transformer parts, etc. have not been carried out.

2/3