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HP LaserJet 5si and 8000 Series Printers - Troubleshooting Print Quality (PQ) Defects

Document number bpl11858

Introduction

Print quality defects can have a number of causes and appear in many different forms. These defects include faded print, missing print, repetitive defects, smeared or smudged, or postal image transfer. There are different causes for the different types of defects. Finding the root cause of any print quality defect is a process of elimination. Many times the media being used is the cause of the issue. For testing purposes it can be very useful to use with standard HP copy paper, this eliminates the media as the source of the problem.

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Troubleshooting instructions

Print quality issues indicate a problem with the paper being used or a part in the printing process is dirty or defective. Inspect the following:

  • The print cartridge may be defective or toner may not be distributed evenly within the print cartridge.

  • The Transfer roller may be dirty or defective.

  • The Fuser may not be fusing the toner to the media properly.

  • The media does not meet HP specifications. Refer to the HP LaserJet Printer Family Print Media Guide for more information. Follow the steps in the sections below in the order listed to determine the cause of the print quality defects.

Perform a half-self-test

The purpose of the Half-Self-Test Check is to determine which process is malfunctioning. Perform the test as follows:

  1. Print a PCL Configuration Page from the Control Panel Test Menu.

  2. Open the top cover after the paper advances halfway through the printer (about five seconds after the Main Motor begins rotation). The leading edge of the paper should have advanced past the print cartridge.

  3. After stopping the page, remove the print cartridge and the paper. If the paper is not wrinkled at this point, the issue is not with the trays or paper input devices.

  4. Perform the half self-test again, letting it go a second longer so the paper reaches the transfer roller assembly. If the paper is not wrinkled at this point, the issue is most likely with the fuser assembly or output area.

    NOTE: It may be necessary to perform the half self-test multiple times to confirm which area has the issue.

Perform a paper path test

HP LaserJet 5si printer

  1. Press the MENU key until TEST MENU is displayed.

  2. Press the ITEM key until PAPER PATH TEST is displayed.

  3. Press SELECT.

  4. When INPUT = TRAY 1 is displayed, press theplus (+) key until INPUT = TRAY 2 is displayed.

  5. Press SELECT.

  6. When COPIES = 1 is displayed press the plus (+) key once. COPIES = 10 will be displayed.

  7. Press SELECT.

  8. The paper path test will initialize.

HP LaserJet 8000 printer

  1. Press the MENU key until INFORMATION MENU is displayed.

  2. Press ITEM key until PAPER PATH TEST is displayed.

  3. Press SELECT.

  4. When INPUT = Tray 1 is displayed, press the plus (+) key until INPUT = TRAY 2 is displayed.

  5. Press SELECT.

  6. When COPIES = 1 is displayed, press the plus (+) key once. COPIES = 10 will be displayed.

  7. Press SELECT.

  8. The paper path test will initialize.

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Repetitive defects

A repetitive defect is one that repeats at even intervals across the page, or down the page depending on the orientation of the print job.

Repetitive print defects are usually associated with a specific roller within the printer or the print cartridge. Use a repetitive defect ruler to isolate the cause of repetitive print defects or use the table below and a ruler. Align the first occurrence of the defect with the top of the ruler and measure to the next occurrence of the defect to determine the roller in question. When it is determined the defect pattern matches the pattern of the ruler, replace the indicated roller.

If the repetitive defect does not match any of the rollers on the defect ruler, it may be caused by dirty pick-up or feed rollers. Clean all the rollers in the paper feed path and try printing again.

Repetitive defects that are not at even intervals may be caused by paper that is out of specifications or by worn gears in the main drive assembly, both of which can cause the paper to slip.

Table 1: Repetitive defect distances

Distance from first occurrence to second
Roller indicated by distance
44 mm (1.73 inches)
Registration roller
44.4 mm (1.75 inches)
print cartridge primary charging roller
47 mm (1.86 inches)
Face-up delivery roller
53.5 mm (2.11 inches)
print cartridge developing roller
58.4 mm (2.30 inches)
Transfer roller
94 mm (3.71 inches)
Fuser lower roller
94 mm (3.71 inches)
print cartridge photosensitive drum
125 mm (4.92 inches)
Fuser upper roller

The most common causes for repetitive defectives are:

  • Paper that does not meet specifications in the HP LaserJet Printer Family Print Media Guide .

  • Damage to the print cartridge.

  • Defective or worn transfer roller.

  • Dirty pick-up/feed rollers.

  • Defective or dirty fuser assembly.

  • Worn gears on the main drive assembly which cause slipping.

    NOTE: If none of the above steps resolve the issue then call HP Support or a local authorized service provider for further assistance.

Click here for more support options.

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Outline of character (Electrostatic offset)

The outline of the printed image on the first part of the page is repeated at 125 mm down the page. This outline will show on the trailing edge of the paper. The defect is referred to as electrostatic offset or as dirty print.

NOTE: Only the outline of each character is repeated. It looks like a typewriter letter struck the paper without a ribbon in the printer. This defect usually appears during long print jobs.

The cause of this is that as a pile of toner is deposited on a page and sent though the fuser, the edges of the toner pile are not subject to the same heat and pressure as the center of the pile. To minimize this defect try the following steps:

  1. Ensure the paper is within specification, try another type of paper, or try HP paper. Try using a slightly heavier paper.

  2. Lower the print density.

  3. Ensure the print cartridge is a genuine HP part.

  4. Check humidity. This defect may be more evident in a dryer (low humidity) environment; therefore, try increasing humidity.

    NOTE: Replacing the fuser may solve the issue. However, this repetitive defect may return. Going through the above steps should be done to help minimize this print quality defect.

Click here for more support options if the above steps do not solve the issue.

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Postal image transfer

When the printed page is folded or stacked, toner is transferred onto the opposing surface of the paper. A common occurrence of this is when sending letters through the mail. Some machinery, such as that used by the US Postal Service to sort mail, may apply the necessary pressure and agitation to cause this toner image transfer phenomenon. Pressure exerted on the paper causes this issue and is inherent to all laser printers, regardless of the manufacturer.

The laser printing process uses a pigmented plastic powder (toner) to form a print image that is first transferred to a sheet of paper (or other print medium) and then melted (fused) onto the surface of paper to form a permanent image. Though paper is usually thought of as being soft, it is actually quite abrasive. When the printed page is folded, movement under pressure between a paper surface and the toner image may cause the paper to abrade (scratch) the toner, causing a transfer of the toner material onto the opposing surface of the paper. This can be demonstrated by rubbing a print image against (or into) a clean sheet of paper.

The potential for this problem can be significantly reduced by minimizing the amount (or height) of toner used to produce the print image, by using paper that is less abrasive, or by ensuring optimal fusing of the toner (print) image to the paper. There is no permanent fix.

  • Decrease the print density from the Print Quality menu on the printer’s control panel. The amount of toner used to produce a print image is controlled by the print density dial, slide, or Control Panel settings in the HP LaserJet printers. The print density should be adjusted for a lighter image to reduce the amount (height) of toner prone to abrasive transfer.

    1. Press the ITEM key until PRINT QUALITY MENU is displayed.

    2. Press the ITEM key until PRINT DENSITY is displayed. The default is set to 3.

    3. Press the Plus (+) key to reduce the density setting.

    4. Press the SELECT key to save the new setting. An asterisk (*) will appear to the right of the setting.

  • Try a different media. HP LaserJet printers are designed for optimum results with xerographic (or laser) bond papers, such as HP LaserJet paper. The properties of this type of paper (surface roughness, composition, moisture content, and other properties) are such that the other causes of potential toner transfer are minimized. Photocopy papers are typically less abrasive than other types of paper (such as writing bond) and are also formulated to ensure optimal fusing of the toner image. Using other types of paper will generally yield less than optimal results in laser printers. For help in selecting paper suitable for use in HP LaserJet printers, refer to the HP LaserJet Printer Family Print Media Guide. Try decreasing or turning off REt (Resolution Enhancement Technology).

    NOTE: It is best to change the REt setting from the printer driver or software application (driver and software settings override control panel settings).

To access REt features from the driver, follow these instructions:

  1. Click Start , Settings, and then Printers.

  2. Right-click the HP LaserJet printer driver .

  3. For Windows 95 and 98, select Properties , then Finishing . For Windows NT 4.0, select Document Defaults.

There is presently no way to entirely eliminate the possibility of toner transfer due to the way in which all laser printing is accomplished. However, using these techniques should yield more satisfactory results and will often reduce the problem to less visible levels.

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Smeared or smudged print

When the page prints, the toner is smeared, smudged, or streaked. The most common causes of these problems include:

  • Media out of specification by HP LaserJet Printer Family Print Media Guide standards

  • Refilled or recycled third party print cartridges

  • print cartridge stoppers (called CG stoppers) out of place or broken, preventing print cartridge from seating properly

  • Envelope levers set for printing envelopes while printing regular paper

  • Excess paper debris in the paper path

  • Recycled third party fusers

Refer to the following for troubleshooting steps to isolate the issue and begin printer repair.

After each step, print a self-test page, or more than one, to verify printer functionality

Check that the media being used is within HP specifications for the printer. Refer to the HP LaserJet Printer Family Print Media Guide if necessary. Test media should be 20 lb bond non-coated, non-Inkjet, non-photo paper. Also, try a test print from a new batch or ream of paper.

Perform a half self-test to determine at which point in the printing process the problem occurs.

See instructions on how to perform a half-self-test.

  1. Print a configuration page and check the fuser page count. If the current maintenance kit has between 150,000 and 250,000 pages on it, the fuser may need to be replaced. If the printer is close to the 350,000-page service interval, user maintenance should be performed. Replace the maintenance kit and try printing again.

  2. Look inside the fuser and inspect the paper path, especially around the pan area for built up toner. Toner and/or paper dust can build up inside the fuser around the cleaning roller, and is difficult to see.

  3. Remove the fuser and inspect for paper debris in the fuser/fuser roller and around the paper path leading to the fuser. Clean as necessary.

  4. Verify that the fuser is a genuine HP fuser and not a remanufactured or third party fuser. The fuser rollers in a genuine HP fuser will always be black.

  5. Check that the gray envelope levers on the left and right side of the fusing assembly are seated and in the down position. The levers should be pushed down for printing on paper and up for printing on heavier media and envelopes.

  6. Check for an old or third party print cartridge. If found, test with a new HP cartridge.

    NOTE: print cartridges are rated for 15,000 images at five percent coverage. It is possible to wear out the gears and the cartridge seals before the “TONER LOW” message displays if the 15,000-image expectancy is exceeded.
  7. Check for spilled toner along the paper path and clean as necessary.

  8. Remove the transfer roller and check all of the contacts and springs. If any are damaged or missing, the feeder assembly will need to be replaced by a qualified technician.

  9. Inspect the print cartridge stoppers (called CG stoppers). See Figure 1 below for details of the CG stoppers. An improperly positioned/seated print cartridge can cause smearing. Also check the front and rear print cartridge guides for cracks or broken plastic. The print cartridge guides are the large black plastic pieces on which the cartridge rests.

    Figure 1: The CG stoppers

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Faded print

When a page prints, a part of the page or all of it is faded. Some of the most common causes include:

  • Media in not in specifications according to HP LaserJet Printer Family Print Media Guide.

  • Econo mode set to on or density setting too light

  • Refilled or recycled third party print cartridges

  • Dirty contacts on high voltage power supply

  • Bad power source

  • Transfer roller not seated properly

  • Low humidity

Different issues can cause faded print. Refer to the following for troubleshooting steps to isolate the issue. Perform a half-self-test to determine the cause of the faded print. See instructions on how to perform the half self-test.

When the paper is stopped under the print cartridge, remove the TC and pull the flap open and inspect the Image on the drum.

Image is faded on drum

  1. Inspect the power source; turn the printer off and plug directly into a wall outlet and/or try a different power outlet.

  2. Verify the ECONOMODE setting is turned off.

    1. Press the MENU key until PRINT QUALITY MENU is displayed.

    2. Press the ITEM key untilECONOMODE is displayed.

    3. Press the Plus (+) key to select ECONMODE = OFF.

    4. Press the SELECT key to save the new setting. An asterisk (*) will appear to the right to verify the new setting is saved.

  3. Try a higher density setting.

    1. Press the MENU key until PRINT MENU is displayed.

    2. Press the ITEM key until PRINT DENSITY is displayed. The default is set to 3.

    3. Press the Plus (+) key to increase the density setting.

    4. Press the SELECT key to save the new setting. An asterisk (*) will appear to the right of the setting to verify the new setting is saved.

  4. Verify that a HP print cartridge is being used.

  5. Reseat the HP print cartridge and visually inspect the four connection points on the inside right end of the print cartridge. If they are dirty or corroded, clean the connections. Clean using a dry, lint free cloth. If damaged, replace with a HP print cartridge.

  6. Try another HP print cartridge.

  7. Inspect and clean High Voltage Power Supply (HVPS) Contacts. The HVPS contact springs mount on the High Voltage Power Supply PCA and protrude through the print cartridge cavity to contact the print cartridge. Verify that the contacts are not dirty or corroded, and that the spring action is functional. If dirty, clean using dry, lint free cloth. If this does not work, use a minimal amount of alcohol.

If image looks good on the drum

  1. Check that the paper being used falls within HP specifications for the printer. Refer to the HP LaserJet Printer Family Print Media Guide, if necessary. Test with 20# bond non-coated, non-Inkjet, non-photo paper. Also verify environmental conditions (does this faded page only occur on duplex jobs, indicating dry media). If necessary, try a test print from a new batch/ream of paper.

  2. Inspect the power source; turn the printer off and plug directly into a wall outlet and/or try a different poweroutlet.

  3. Reseat the transfer roller.

  4. Verify both transfer roller holders in the feeder assembly have spring under them and spring up and down when manipulated.

  5. Inspect the print cartridge stoppers (See Figure 2). When either of these are broken the print cartridge does not set correctly. An improperly positioned print cartridge can cause smearing. Also check the front and rear print cartridge guides for cracks or broken plastic. The print cartridge guides are the large black plastic pieces on which the cartridge rests.

    Figure 2: The CG stoppers

    NOTE: If none of the above steps resolve the issue then call HP Support or a local authorized service provider for further assistance.

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Contact HP?

If the issue is unresolved, click here to contact HP support (http://thenew.hp.com/country/us/eng/contact_us.html) and provide them with the following information:

  • Document number bpl11858 used for troubleshooting and a brief problem description to assist HP support in resolving the issue.

  • For repetitive defects, what is the distance between occurrences?

  • What is the page count on the printer?

  • For all defects, is the print cartridge being used a genuine HP part?

  • Was another new genuine HP print cartridge tried? If so what were the results?
  • Is the fuser assembly a genuine HP part?

  • Were any of the parts inspected damaged or worn?

  • Does the paper being used meet HP specifications?

  • Is the printer an HP LaserJet 5si or an HP LaserJet 8000?

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