Ricoh A012 Technical Bulletin DS320

Technical Bulletin No. RTB-006

SUBJECT: Incomplete Solid Filling DATE: Feb. 28, ’91

PAGE: 1 of 3

PREPARED BY: M. Furusawa
CHECKED BY: T. Ito

CLASSIFICATION:

Action Required
Troubleshooting
Retrofit Information

[ SYMPTOM ]

FROM: Technical Support Department
Copier Technical Support Section

Revision of service manual
Information only
Other

MODEL:
COSMOS

1. The trailing corners of solid cross images become white.

2. The trailing edges of solid areas have low ID.

[ ACTION ]

Procedure 1.
Do the following procedure:

NOTE: This is taken from the troubleshooting section of the COSMOS service manual
(page 12-38).

1. Check the charge wire position, and clean the wire and grid plate.
(Make sure the wire cleaner does not push the wire to the left.)

2. Check the doctor gap.
(The gap might be too wide.)

3. Increase the development bias from -600V to -650V by SP33.

Technical Bulletin No. RTB-006

SUBJECT: Incomplete Solid Filling DATE: Feb. 28, ’91

PAGE: 2 of 3

Procedure 2.
If the procedure 1 dose not solve the problem with incomplete solid filling to the customer’s

satisfaction, do the following:

1. Change the charge corona receptacle from P/N:AD021054 (Varistor=866V) to
P/N:A0129125 (Varistor=720V).

NOTE: P/N:A0129125 has been newly registered as a service part for this

troubleshooting procedure.
Keep the original charge corona receptacle for future use.

2. Reset SP33 data from "1" to "0" (-650V to -600V).

3. Make sure that there is no dirty background on the copy.

If dirty background is observed, change the SP33 data from "0" to ’2" (-600V to

-550V).

NOTE: The ID on the copy will be slightly lower at this low bias setting.

[ Explanation ]

Vd

Vb

Toner

Vr

Vd : Drum potential in white areas
Vr : Drum residual potential in black
areas of original
Vb : Development bias

Vb - Vr : Development potential
Vd - Vb : Dirty background margin

Vb − Vr

Vd − Vb

= A

……………

(1)

Quantity "A" derived in the above equation (1) affects the solid filling.

If "A" is low, the solid filling will be worse.
However, if "A" is high, dirty background will occur as side effect.