Oki Microline 520 Service Handbook

Also see for Microline 520: User guide Product update Guía del usuario Manual do utilizador User guide

Contents

Oki Microline 520 Service Handbook Manual pdf 105 page image

%3.3.02 Printhead Gap Adjustment3.3.02 Printhead Gap AdjustmentGeneral InformationBefore performing this adjustment, always verify that the printhead is properly installed. Thisadjustment should be performed when the following parts are replaced.1. Printhead (3.2.02)2. Space Motor Assembly (3.2.11)3. Space Rack (3.2.13)4. Guide Rail (3.2.15)5. Platen Assembly (3.2.19)6. Carriage Shaft (3.2.25)NOTE:Place a new ribbon cartridge in the printer before testing for parallelism.If the density of the top portion of the characters differ from that of the bottom portion, follow steps10 - 12.This adjustment is comprised of four phases.1. Setup PhaseSteps 1-5The cover is removed and the printhead is placed at a known reference point.2. Printhead Gap Modification PhaseSteps 6 - 10The distance between the printhead and the platen (at the left side of the platen) is modified byturning the adjust screw which varies the vertical position of the space motor.3. Parallel Adjustment PhaseSteps 11 - 12The adjust cam lever is moved to ensure the printhead moves parallel to the platen.4. Verification PhaseSteps 13 -14Verifies that the parallel adjustment phase did not affect the printhead gap modification phase.ProcedureSetup Phase1. Remove the upper cover and pull roller assembly.2. Move the change lever to the rear paper feed position.3. Rotate the platen.4. Set the gap change gear (Figure 1 A) to Range 2 by turning the adjust screw using a smallphillips screwdriver. Turn this screw slowly while moving the carriage (1) to the left (if turning thescrew counter clockwise) or (2) to the right (if turning the screw clockwise). This will allow easierrotation of the gears and prevent the gears from being stripped.DO NOT DISENGAGE THE ADJUST GEAR! 5. Remove the ribbon protector.Printhead Gap Modification Phase6. Slide the carriage assembly to the left side of the platen.7. Check the printhead gap. Use a 0.014 inch or 0.35 mm feeler gauge. The printhead gap mustmeasure 0.014 +/- 0.001 inch (0.35 +/- 0.03 mm).8. Use a large, straightened paper clip (Figure 1 B) to push down on the adjust gear. This willdisengage the adjust gear from idle gear D.9. Use a small phillips screwdriver to turn the adjust screw. (Figure 1 C)Turning the screw CLOCKWISE will increase the printhead gap.Turning the screw COUNTERCLOCKWISE will decrease the gap.10. Slide the carriage assembly to the right side of the platen.Parallel Adjustment Phase11. Check the printhead gap at the right side of the platen.12. If the gap measurements are different between the left and right positions, turn the adjust camML520/521 ( 96-02-04 )