Laser Beam Pitch Adjustment - Ricoh A284 Service Manual

LASER UNIT

6.2.3 LASER BEAM PITCH ADJUSTMENT

After replacing the LD unit, perform the laser beam pitch adjustment. There are two
laser beam pitch adjustment procedures: one for 400 dpi, and one for 600 dpi.
These adjustments use the following SP modes.
• SP2-109-1: LD Beam Pitch Adjustment – 400 dpi
• SP2-109-2: LD Beam Pitch Adjustment – 600 dpi
• SP2-109-3: LD Initial Setting – 400 dpi
• SP2-109-4: LD Initial Setting – 600 dpi
⇒
• SP2-110, no. 1: Image Resolution Change – 400 dpi
• SP2-110, no. 8: Image Resolution Change – 600 dpi
• SP2-902-3, no.16: Test Pattern Printing – Cross Stitch
1. Do SP 2-109-8.
2. Input the value "144" into SP2-109-1.
3. Perform SP2-109-3.
⇒
4. Print out 400 dpi test pattern A3 (11x17), change SP2-110 to 1 and print out the
cross stitch test pattern using SP2-902-3 no. 16. For 600 dpi, set SP2-110 to 8.
5. Write the value of SP2-109-1 on the test pattern (in this case "144").
6. Change the value of SP2-109-1 and print another test pattern, repeating steps
2 to 4. Print about 5 patterns with different values for SP2-109-1 (e.g. "48", "96",
"192", "240").
7. Check these test patterns. If the laser beam pitch is not correct, the image
looks like a black vertical strip pattern.
NOTE: As an example, if the pattern made with the value "192" has less
obvious strips than the other print outs, the correct value is near "192".
8. Adjust the laser beam pitch position until the thin lines are of uniform thickness
(no striping effect should appear on the printout), doing steps 1, 2, and 3 (in
step 1, input a value which is estimated to be correct, then do steps 2 and 3,
then if necessary go back to step 1 and try another value).
9. After adjusting the laser beam pitch for 400 dpi, adjust the laser beam pitch for
600 dpi, using the same procedure as for 400 dpi (use the SP modes for 600
dpi). The laser beam pitch for 600 dpi should be 24 ~ 48 more than for 400 dpi.
Adjustment not complete
A283/A284
Feed Direction
A284R512.WMF
6-8
Feed Direction
A284R513.WMF
Adjustment complete
Rev. 08/2000
SM