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HP Designjet 600 Series Printers - Media Skew

	Parts required (part numbers are subject to change)
	Identify skewing issue
	Clean the drive roller
	Check/replace the media spindle
	Check/replace the right rollfeed assembly
	Check/replace the overdrive gear assembly/overdrive assembly
	Drop detect calibration
	Accuracy calibration

KRS document number: BPP90027

Last updated: 22 Aug, 2001

Minimum skill level: 2

Media skewing issues on the HP Designjet 600 printer can be attributed to several causes. The most common causes of media skew are a dirty drive roller; malfunctioning right roll feed assembly, or a faulty overdrive gear assembly. Other causes may include the media spindle, the media itself, or the overdrive assembly. Use the steps below to determine the actual cause of the skewing issue.

Parts required (part numbers are subject to change)

Part description	Model C2847A	Model C2848A
Right rollfeed assembly (required)	C4704-60199	C4704-60199
Overdrive gear assembly (required)	C4705-60089	C4705-60089
Media spindle (required)	C2847-60093	C2848-60011
Overdrive assembly (required)	C4705-60121	C4706-60121

Identify skewing issue

Accurately identifying the skewing issue will lead to a quicker resolution and repair time. First determine if the skew is happening on roll media, sheet media, or both. If the issue is affecting roll media only, the most common causes are the right rollfeed assembly, or the media spindle. If the issue affects sheet media only, the most common cause would be a dirty drive roller. If skewing happens on both types of media, the solution may be a combination of roll and sheet troubleshooting. In rare cases the printer's overdrive assembly may be the cause of the skewing issue.

Clean the drive roller

1. Switch the printer on, and allow printer to complete initialization.
2. Press the ENTER button to access the printer's menu.
3. Using the arrow buttons, scroll to the Utilities menu and press the ENTER button.
4. Using the arrow buttons, scroll to the Statistics submenu.
5. Simultaneously press the ENTER and the UP arrow buttons to access the Service tests menu.
6. Using the UP arrow button, scroll to SERVICE TESTS "X motion control", and press ENTER.
7. Remove Media Press Enter should appear. Remove any media from the printer.
8. Raise the printer's window (holding the window sensor down with a pen, pencil, or small screwdriver).
9. Press the ENTER button.
10. Press the UP arrow button until the drive roller reaches a convenient speed for cleaning.
11. Using a lint free cloth dampened with water, thoroughly clean the entire drive roller surface while it is rotating.
12. Press the ENTER button to stop the roller.
13. Press the ENTER button to return to the Service Tests menu.
14. Press the PREVIOUS button until STATUS "Ready for Media" is displayed.
15. Allow the driver roller to dry.
16. Try loading media.
17. If loading is successful, repeat loading procedure with both roll and sheet media (preferably larger than 8.5 x 11) two times each, to prove product functionality.
18. If loading is unsuccessful, or problems persist, continue with the remaining steps.

Check/replace the media spindle

1. Check that the left endcap is securely pushed into the media roll tube.
2. Remove the media spindle from the printer.
3. Check the right side of the spindle for damaged or missing teeth. Replace the spindle if needed.
4. If the spindle is replaced, load media onto new spindle, and try reloading media.
5. If loading is successful, repeat loading procedure with both roll and sheet media (preferably larger than 8.5 x 11 inches) two times each, to prove product functionality.
6. If loading media is unsuccessful, or no problem is found with the media spindle, continue with the remaining steps.

Check/replace the right rollfeed assembly

1. Remove the media spindle from the printer.
2. Check the right rollfeed assembly for ease of rotation, and for damaged/missing teeth. Use the eraser end of a pencil to move the rollfeed assembly.

NOTE: The right rollfeed assembly gear should be very hard to rotate.

3. If the rollfeed assembly moves easily, or damaged/missing teeth on assembly are noticed, replace the right rollfeed assembly.
4. After replacement of the right rollfeed, reassemble the printer.
5. Verify printer functionality. Perform media loading procedure with roll and sheet (preferably larger than 8.5 x 11) media, two times each.
6. If media is loading correctly, the problem has been solved.
7. If no problems with the right rollfeed assembly are noticed or the problem is not solved, continue with the remaining steps.

Check/replace the overdrive gear assembly/overdrive assembly

1. Open the printer's window.
2. Manually lift the bail assembly.
3. Try turning the overdrive backwards by hand.
4. If the overdrive moves backwards, replace the overdrive gear assembly.
5. After replacing the overdrive gear assembly and reassembling the printer, perform the drop detect and accuracy calibrations as listed below.

NOTE: The overdrive assembly should only be replaced if noticeable damage is present. If overdrive is replaced perform the drop detect and accuracy calibrations as listed below.

Drop detect calibration

1. Press ENTER at the Status display.
2. Use the arrow buttons to scroll to the Utilities menu, and press ENTER.
3. Simultaneously press the ENTER and UP arrow buttons to access the Service test submenu.
4. Using the arrow buttons, scroll to Drop Detect Calib and press ENTER.
5. Press the ENTER button when calibration is complete.

Accuracy calibration

1. Use a sheet approximately 24 x 36 inches, or roll media. To get the best results for an accuracy calibration, a polyester/matte film should be used.

NOTE: If a polyester or matte film is not available, use HP Coated media when performing an accuracy calibration.

2. Load the media. If using D-size media (24 x 36 inches) load the short edge as the leading edge in 24-inch models, and the long edge as the leading edge for 36-inch models. E-size media (36 x 48 inches) can also be used on 36-inch models.
3. Press ENTER at the Status display.
4. Use the arrow buttons to scroll to the Utilities menu, and press ENTER. Set menu mode to full if not already in full mode.
5. Simultaneously press the ENTER and UP arrow buttons, to access the Service Test menu.
6. Using the arrow buttons, scroll to Accuracy Calib, and press ENTER.
7. Press the UP arrow button to select Create plot. A "Creating calibration plot" message will be displayed.
8. Wait until the "Remove media/Continue" message displays, then remove the media.
9. Press the DOWN arrow button to "Continue." The "Create plot / Measure plot" message displays.
10. Press the DOWN arrow button to select Measure plot.
11. Rotate the plot so the edge with arrows point to the leading edge, reload the plot with print side down.
12. The printer will load the plot and measure the alignment marks using the edge sensor on the pen carriage.
13. Press the DOWN arrow button to continue when the "Calibrate done / Continue" message is displayed and the plot is fed out. The accuracy calibration is now complete.
14. Verify printer functionality. Perform media loading procedure with both roll and sheet (preferably larger than 8.5 x 11 inches) media, two times each.

Copyright (C) Hewlett-Packard Co. 2000
This information is subject to change without notice and
is provided "as is" with no warranty.
Hewlett-Packard shall not be liable for any direct,
indirect, special, incidental or consequential damages
in connection with the use of this material.

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