Carriage Unit Replacement; Document Pressure Sheet (Sponge Sheet) Replacement - Canon MP640 Service Manual

(3) Carriage unit replacement

To replace the carriage, the carriage rail must be removed from the main chassis (by removing the screws).
Before removing the screws, put a mark on the main chassis to indicate the carriage rail position.
After replacing the carriage, return the carriage rail to the original position while aligning the rail to the mark on the chassis.

(4) Document pressure sheet (sponge sheet) replacement

1) Peel off the cover sheet from the double-sided adhesive tape on the back of the document pressure sheet.
With the long-side down, position the upper-left corner of the document pressure sheet at the scanning reference point on the
platen glass (back left where the red lines cross in the photo above).
2) Slowly close the document pressure plate while maintaining the hinge position. The document pressure sheet will attach to the
plate frame.
3) Open the plate to confirm the following:
- No extension of the sponge edges over the mold part of the upper scanner cover.
- No gap between the platen glass reference edges and the corresponding sponge edges.
- No shades or streaks in monochrome test printing without a document on the platen glass.
(5) Ink absorber counter setting
Before replacement of the logic board, check the ink absorber counter value, and register it to the replaced new logic board. (The
value can be set in 10% increments.)
In addition, according to the ink absorber counter value, replace the ink absorber (ink absorber kit). When the ink absorber is
replaced, reset the applicable ink absorber counter (to 0%). See
<4-3. Grease Application & 4-4. Special Notes on Servicing>
4-2. Service Mode, for details.
49 / 54