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HP Designjet 1000 Series Printers - Ink Tube System Causing Switch Power off Check Printhead Path Messages

Document number: BPP90220

Last updated: 02-Dec-2003

Minimum skill level: 2

Introduction

This document is specific to a Switch power off, check printhead path message caused by an ink tube system failure (in reference to service notes C6074A-19E, C6075A-19E, C6074B-12E, and C6075B-12E).

The cause of this issue is attributed to the premature wear of the ink tube system due to constant heavy usage. Over time, as the carriage moves back and forth, the tube carrier weakens and stretches and consequently creates a bow in the ink tubes. The bow in the tubes causes the tube carrier to get scratched and cut by the rear tube guide and possibly by the front guide, which creates excess friction. The resulting backpressure and friction on the carriage causes the error message. This message usually occurs while the carriage is in motion (left-side to right-side) and might occur at any time (initialization, loading media, printing). Use the steps listed in this document to determine the cause of the failure and replace the appropriate parts.

Parts required (part numbers are subject to change)

Part description	Models C6074A/B, C6075A/B
Ink Tube System, includes Mylar strip (Required)	C6074-60415

Troubleshooting steps

If any of the troubleshooting steps listed below solve the problem, attempt to verify printer functionality by printing several internal prints. If functionality is verified, no additional parts should be replaced.

1. Attempt to duplicate the message by turning the printer on, reloading the media, and printing several test prints.

2. Note the movement and position of the carriage when the error occurs.

3. If the carriage stops on the left-hand side (roughly 12 inches from the ink supply station), unplug the power cable from the printer, open the top cover and try to move the carriage to the right. Closely inspect the ink tubes for wear, and check for ink tube binding or catching on the tube guide (stopping/hindering carriage movement). If true, continue with the remaining steps below.

   NOTE: If the steps above do not describe the issue correctly, refer to the work instruction for a typical “Switch Power Off, Check Printhead Path” message (bpp90070).

Check/replace the Ink Tube System

1. Turn the printer off.

2. Remove the old Ink Tube System (refer to pages 8-53 of the Service Manual).

   NOTE: If removal and installation instructions are needed for reference during any repairs performed, refer to the HP Designjet1000 Series Service Manual available on the Computer Care Web site for review or download.
   NOTE: If the printer is installed on a Multi-roll feeder accessory, some additional disassembly is required to gain access to the printer. Instructions for multi-roll disassembly are listed at the bottom of this document for reference.

3. Move the carriage assembly to the right side of the printer.

4. Clean the rear tube guide assembly with a moistened lint free cloth to prepare the mounting of the Mylar tape.

   Figure 1:Cleaning the rear tube guide assembly

   

5. Remove the backing on the Mylar tape and align the line on the tape with the front edge of the rear-tube guide so that the narrower section is towards the front of the printer. Do not attach the tape yet.

   Figure 2:Aligning line on Mylar tape with front edge of rear-tube guide assembly

   
   NOTE: Ensure that the Mylar film is perfectly aligned with the rear Tube Guide surface with no protrusions or unevenness.

6. Carefully position the Mylar tape about 1/4 of an inch from the left-end of the rear-tube guide (do not go all the way to the end as the beveled edge will cause crimping of the tape).

   Figure 3:Attaching the Mylar tape

   

7. Ensure tape is evenly positioned and any air bubbles are smoothed out along the tape.

   Figure 4:Smoothing out the air bubbles along the Mylar tape (view from rear of printer)

   

8. Carefully fold under the narrow section of the tape to the underside of the rear tube guide assembly and smooth out any air bubbles.

   Figure 5:Installing Mylar tape under rear-tube guide assembly (view from front of printer)

   

9. The Mylar tape should look like the image below.

   Figure 6:Final installation of Mylar tape (view from top of printer)

   

10. Once the Mylar tape is installed, install the new Ink Tube System (refer to pages 8-53 of the Service Manual).

11. Following replacement, verify printer functionality.

Scan Axis test

1. Turn the printer off using the power switch on the front of the printer.

2. Hold down the Color key land turn the printer on.

   NOTE: Wait until the message, “Initializing” appears, and then release the Color key.

3. Once inside the Service Tests menu, scroll to "5 Scan Axis," and press Enter.

4. Allow the printer to complete the test.

5. When finished, SCAN AXIS BACKWARDS values will display on the front panel. Note all five values and press Enter.

6. The SCAN AXIS FORWARD values will now appear. Again, note the five values.

7. Use the table below to determine if the values are within the printer limits:

	Scan-Axis Forward		Scan-Axis Backwards
	Normal	Maximum	Normal	Maximum
Avg. PWM	165	185	-165	-185
Max. PWM	220	240	220	240
Stabilize Dist.	1800	2400	1800	2400
Avg. Speed offset	2.4	10	2.4	10
STD Speed offset	4.4	10	4.4	10

Multi-Roll feeder disassembly

Only remove the corresponding side cover of the Multi-Roll that requires maintenance. For example, only remove the right-side cover of Multi-Roll if only the right-end cover of the printer requires removal to complete the necessary service. Follow the steps listed below to gain access to the printer to complete the necessary service.

NOTE: Only ONE CE needs to be dispatched to perform service on an HP Designjet 1000 series printer attached to a Multi-Roll feeder.

Removing the Multi-Roll feeder left-side cover

WARNING: Turn both the printer and the Multi-Roll feeder off and disconnect them from the power source prior to performing any maintenance.

1. Open the left door of the Multi-Roll feeder.

2. Loosen the two (2) screws that secure the left door to the Multi-Roll feeder.

   Figure 7:Screws securing the left door

   

3. Remove the left door.

   CAUTION: Be careful when removing the door not to break it.

4. Remove the two (2) star screws (orange) that secure the front-top cover to the Multi-Roll feeder.

   Figure 8:Two (2) star screws securing the front-top cover

   

5. Remove the Multi-Roll feeder top cover.

6. Remove six (6) T-20 screws that secure the left-side cover to the Multi-Roll feeder from the front.

   Figure 9:Six (6) screws securing the front left-side cover

   

7. Remove the seven (7) T-20 screws that secure the left-side cover to the Multi-Roll feeder from the rear.

   Figure 10:Seven (7) screws securing the rear left-side cover

   

8. Remove the left-side cover.

   Figure 11:Removing the left-side cover

   

Removing the Multi-Roll feeder right-side cover

WARNING: Turn both the printer and the Multi-Roll feeder off and disconnect them from the power source prior to performing any maintenance.

1. Remove the right door and front-top cover from the Multi-Roll feeder (follow Steps 1 through 5 of the previous section and remove the right door instead of the left).

2. Remove six (6) T-20 screws that secure the right-side cover to the Multi-Roll feeder from the front.

   Figure 12:Six (6) screws securing the front right-side cover

   

3. Remove nine (9) T-20 screws that secure the right-side cover to the Multi-Roll feeder from the rear.

   Figure 13:Nine (9) screws securing the rear right-side cover

   

4. Open the rear-top cover.

   Figure 14:Opening the Rear-top cover

   

5. Release the cable that is attached to the top of the right-side cover.

   Figure 15:Cable release

   

6. Remove the right-side cover.

   Figure 16:Removing the right-side cover.

   

Installation of covers

Follow the procedures listed above in reverse order.

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