HP DesignJet T770 User Manual

							17 Troubleshooting ink cartridge and
printhead issues
●Cannot insert an ink cartridge
●
Ink cartridge status messages
●
Cannot insert a printhead
●
The front-panel display recommends reseating or replacing a printhead
●
Clean the printheads
●
Clean the printhead drop detector
●
Align the printheads
●
Printhead status messages
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							Cannot insert an ink cartridge
1.Check that you have the correct type of cartridge (model number).
2.Check that the colored label on the cartridge is the same color as the label on the slot.
3.Check that the cartridge is correctly oriented, with the letter or letters marking the cartridge label
right-side up and readable.
CAUTION:Never clean inside the ink cartridge slots.
Ink cartridge status messages
These are the possible ink cartridge status messages:
●OK: the cartridge is working normally, with no known problems.
●Missing: there is no cartridge present, or it is not correctly connected to the printer.
●Low: the ink level is low.
●Very low: the ink level is very low.
●Empty: the cartridge is empty.
●Reseat: you are recommended to remove the cartridge and then reinsert it.
●Replace: you are recommended to replace the cartridge with a new cartridge.
●Altered: there is something unexpected about the cartridges status.
●Expired: it is past the cartridges expiration date.
Cannot insert a printhead
1.Check that you have the correct type of printhead (model number).
2.Check that you have removed the two orange protective caps from the printhead.
3.Check that the colored label on the printhead is the same color as the label on the slot.
4.Check that the printhead is correctly oriented (compare with the others).
5.Check that you have correctly closed and latched the printhead cover, see 
Insert a printhead
on page 120.
The front-panel display recommends reseating or
replacing a printhead
1.From the front panel, turn the power off then on.
2.Check the front-panel display message, if it shows the ready message, the printer is ready to
print. If the problem remains continue with the next step.
3.Remove the printhead, see 
Remove a printhead on page 117.
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							4.Clean the electrical connections on the backside of the printhead with a lint free cloth. You can
carefully use a mild rubbing alcohol if moisture is needed to remove residue. Do not use water.
CAUTION:This is a delicate process and may damage the printhead. Do not touch the
nozzles on the bottom side of the printhead, especially not with any alcohol.
5.Reinsert the printhead, see Insert a printhead on page 120.
6.Check the front-panel display message. If the problem remains, try a new printhead.
Clean the printheads
As long as the printer is kept turned on, an automatic cleaning is performed periodically. This ensures
there is fresh ink in the nozzles and prevents nozzle clogs, which ensures color accuracy. If you have
not already done so, please see 
The Image Diagnostics Print on page 160 before proceeding.
To clean the printheads, go to the front panel and select the Image Quality Maintenance menu icon
, then Clean printheads. If you have gone through the Image Quality Diagnostic print process,
you know which colors are failing. Select the pair of printheads which contain the failing colors. If you
are not sure which colors to clean, you can also select to clean all printheads. Cleaning all printheads
takes about nine minutes. Cleaning a single pair of printheads takes about six minutes.
NOTE:Cleaning all printheads uses more ink than cleaning a single pair.
Clean the printhead drop detector
The printhead drop detector is a sensor that detects which nozzles on the printheads are not printing
in order to substitute them for good printing nozzles. If particles, such as fibers, hair or paper pieces,
block the sensor print-quality is affected.
When the front panel displays a warning message that the clean process is needed, you are
recommended to clean the printhead drop detector. If you do not clean the printhead drop detector
immediately, the printer continues working normally, however, the front panel display continues to
show the warning.
CAUTION:Wear gloves to avoid getting ink on your hands.
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							1.Turn off the printer at the front panel.
2.To avoid an electric shock, switch the printer off and unplug it.
3.Open the window.
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							4.Find the printhead drop detector beside the stored printhead carriage.
5.Remove any debris blocking the printhead drop detector.
6.With a dry lint free cloth, wipe the surface of the drop detector to remove any non-visible debris.
7.Close the window.
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							8.Plug in and switch on the printer.
9.Power the printer on at the front panel.
Align the printheads
Precise alignment between printheads is essential for accurate colors, smooth color transitions and
sharp edges in graphical elements. Your printer has an automatic printhead alignment process which
runs whenever a printhead has been accessed or replaced.
In cases where the paper has jammed or you are experiencing problems with color accuracy, see
Color management on page 65; you may need to align the printheads.
NOTE:If the paper has jammed, it is recommended that you reinsert the printheads and initiate the
realignment procedure with the Image Quality Maintenance menu 
.
CAUTION:Do not use transparent or semi-transparent paper to align the printheads.
Reinsert printheads procedure
1.If the realignment process is running and the wrong paper is loaded, press the Cancel key on
the front panel.
CAUTION:Do not print if the realignment process has been canceled. You can restart the
alignment with the Image Quality Maintenance menu procedure.
2.Load the paper you wish to use, see Paper handling on page 31. You can use a roll or cut sheet,
however, it must be A3 landscape or larger.
CAUTION:Do not use transparent or semi-transparent paper to align the printheads.
3.Remove and re-insert all the printheads, see Remove a printhead on page 117 and Insert a
printhead on page 120. This starts the printhead alignment procedure.
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							4.Ensure the window is closed, as a strong light source near the printer during printhead
realignment can affect alignment.
5.The process takes about six minutes. Wait until the front-panel display shows the process
complete before using the printer.
NOTE:The printer prints a calibration image. Do not worry about the image. The front-panel
display shows any errors in the process.
Image Quality Maintenance menu procedure
1.Load the paper you wish to use, see Paper handling on page 31. You can use a roll or cut sheet,
however, it must be A3 landscape or larger (420 by 297 mm).
CAUTION:Do not use transparent or semi-transparent paper to align the printheads.
2.
From the front panel, select the Image Quality Maintenance menu icon , then Align
printheads. The printer checks to see if it has enough paper to run the realignment.
3.If the loaded paper is satisfactory, the printer runs the realignment and prints a realignment
pattern. Ensure the window is closed, as a strong light source near the printer during printhead
realignment can affect alignment.
4.The process takes about five minutes. Wait until the front-panel display shows the process
complete before using the printer.
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							Scanning errors during alignment
If the alignment process fails, a Scanning problems message appears on the front panel. This means
that the alignment has not completed successfully. Therefore the printer is not aligned and the
alignment should be repeated before printing with good image quality. The problem may be due to:
●The paper used was not valid, repeat the alignment with valid paper
●Printhead health problems, clean printheads, see 
Clean the printheads on page 165
●The alignment was done with the window open, repeat the alignment with the window closed
If the problem persists after using valid paper, cleaning the printheads and keeping the window
closed, there may be a failure in the scanning system needing reparation or the printheads, although
clean, may not work and need to be replaced.
Printhead status messages
These are the possible printhead status messages:
●OK: the printhead is working normally, with no known problems
●Missing: there is no printhead present, or it is not correctly installed in the printer.
●Test printhead separately: you are recommended to test the printheads individually to find the
failing printhead. Remove all the printheads and insert them alone one by one, closing the latch
and the carriage cover after every insertion. The front-panel display indicates the failing one
showing the reseat or replace message.
●Reseat: you are recommended to remove the printhead and then reinsert it. If that fails, clean
the electrical connections, see 
The front-panel display recommends reseating or replacing a
printhead on page 164. If that fails, replace the printhead with a new printhead, see Remove a
printhead on page 117 and Insert a printhead on page 120.
●Replace: the printhead is failing. Replace the printhead with a working printhead, see 
Remove a
printhead on page 117 and Insert a printhead on page 120.
●Replacement incomplete: a printhead replacement process has not completed successfully,
re-launch the replacement process and let it finish completely (it is not needed to change the
printheads).
●Remove: the printhead is not a suitable type for use in printing.
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							18 Troubleshooting general printer issues
●The printer will not start
●
The printer does not print
●
The printer seems slow
●
Communication failures between computer and printer
●
Cannot access the HP Utility
●
Cannot access the Embedded Web Server
●
Automatic file system check
●
An AutoCAD 2000 memory allocation error
●
No output when printing from Microsoft Visio 2003
●
Unavailable driver features when printing from QuarkXpress
●
Printer alerts
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							The printer will not start
If the printer will not start (the front panel is blank or the diagnostic LEDs are all off), you are
recommended to replace the firmware, in the following way.
1.Go to the Knowledge Center (see 
Knowledge Center on page 180) and download the firmware.
2.Save the firmware on a USB flash drive. Ideally, the USB flash drive should be empty and
formatted with the FAT filesystem.
3.Ensure that the printer is turned off. Connect the USB flash drive to the printers USB port, then
turn the printer on.
4.When prompted by the front panel, press the OK key.
5.The printer takes about a minute to read the firmware file, then asks you to remove the USB
flash drive.
6.The printer automatically installs the new firmware and restarts the printer.
The printer does not print
If all is in order (paper loaded, all ink components installed and no file errors), there are still reasons
why a file you have sent from your computer may not start printing when expected:
●You may have an electrical power problem. If there is no activity at all from the printer, and the
front panel does not respond, check that the power cable is connected correctly and that there is
power available at the socket.
●You may be experiencing unusual electromagnetic phenomena, such as strong electromagnetic
fields or severe electrical disturbances, which can cause the printer to behave strangely or even
stop working. In this case, turn off the printer using the Power key on the front panel and unplug
the power cord, wait until the electromagnetic environment has returned to normal, then turn it
on again. If you still experience problems, please contact your customer service representative.
●Nesting may be on (T1200 series only) and the printer is waiting for the specified nest wait time
before calculating the appropriate nests. In this case, the front panel shows the remaining time
needed for nesting.
●You may have the wrong graphic language setting, see 
Change the graphic language setting
on page 30.
●You may not have installed in your computer the correct driver for your printer, see the Assembly
instructions.
●If you are printing on a sheet, you must specify Manual Feed as the paper source in your printer
driver.
●The printer may be holding the job for paper or (T1200 series only) accounting information, see
Job status messages (T770 HD and T1200 series only) on page 107.
●You may have requested a print preview (T1200 series only) from your printer driver. This is a
function you can use to check that the image is the one you want. In this case, the preview is
displayed on your screen, and you must click the Print button to start printing.
●If you are using Mac OS with a USB connection, you may find that you need to change the data
encoding (PostScript printers only). Select the Setup menu icon 
, then Printing
preferences > PS > Select encoding > ASCII. Then configure your application to send ASCII
data.
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