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Image Formation Troubleshooting
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Image Formation Troubleshooting
This section illustrates some image defects and their possible causes. Since there are many var[ables in the printing process, it is possible to encounter image defects that are not illustrated below. If you find a defect that is not illustrated, record the probable cause along with the printing environmental conditions and save a copy of the defect for future reference.
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Troubleshooting Image Formation Troubleshooting
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BLANK PAGE (See Table 7-1 8)
FADED PRINT (See Table 7-20)
BLACK PAGE (See Table 7-1 9)
VERTICAL (See
WHITE STRIPES Table 7-21 )
Troubleshooting [image Formation Troubleshooting
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II
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VERTICAL (See
BLACK LINES Table 7-22)
REPETITIVE DEFECTS (See Table 7-24)
Y HORIZONTAL (See
J[
BLACK LINES Table 7-23)
(See
STAINING Table 7-25)
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Troubleshooting
Image Formation Troubleshooting
(See
DROPOUT Table 7-26)
BACKGROUND (See Table
SCATTER 7-28)
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26 Scalable `Wef.ce,
CHARACTER (See Table
VOIDS 7-27)
BOTTOM PORTION BLANK (See Table 7-29)
Troubleshooting Image Formation Troubleshooting
FAULTY
REGISTRATION
IMAGE
SKEW
(See --
Table
7-30) --
(See Table
7-32)
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`-4 SMEARED (See Table PRINT 7-31 ) COMPRESSED (See Table PRINT 7-33)
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Image Formation Troubleshooting
Table 7-18
Blank (White) Page POSSIBLE CAUSE RECOMMENDED ACTION
OCCASIONAL
BLANK PAGES: Make sure the application software is not sending incorrect page length requests, or extra page eject commands. Check with the Network Administrator.
1, Software Configuration.
2. Network Configuration, Some sharing
devices on networks may generate a blank page as a separator. 3. Multiple Feeds. Theprinter maybe feeding two or more pages at once because the paper is difficult to separate. Remove the paper from the paper cassette and fan the edges of the paper to separate the pages. Refer to "Media Specifications" in Chapter 2 to ensure paper meets recommendations. Remove the sealing tape. If unsure, weigh the cartridge: Full weight = 852 grams (30.1 OZ) Empty weight = 730 grams (25,8 OZ) Perform the "Drum Rotation Functional Check' described later in this chapter or try a known good toner cartridge, Replace the toner cartridge if necessarv. Check roller installation and contact. Perform the "Half Self Test Functional Check described later in this chapter. If there is an image on the drum, but not on paper, replace the Transfer Roller. 1. Remove and re-seat the toner cartridge. 2, Check the Laser/Scanner shutter door for proper operation. If defective, replace the Laser/Scanner Assemblv.
ALL PAGES BLANK: 1. Sealing tape left in toner cartridge. 2, Empty or defective toner cartridge.
3. Defective or contaminated Transfer Roller. Without a functional Transfer Roller, toner cannot be pulled from the photosensitive drum to the paper. 4, Laser/Scanner properly. door not opening
(continued on next page)
Troubleshooting
Image Formation Troubleshooting
ALL PAGES BLANK (continued) Check the pins and springs for 5. High Voltage Connector Assembly is functionality. Clean if dirty, replace is defective. The High Voltage Connector defective or missing. Assembly mounts on the DC Controller PCA and uses spring-loaded pins to contact the toner cartridge. 6. DC Controller PCA is defective, The DC Controller supplies the proper voltage to the High Voltage contacts. Replace the DC Controller PCA.
Table 7-19
Black Page POSSIBLE CAUSE RECOMMENDED ACTION
1. Defective toner cartridge. 2. Light is leaking into the printer. 3. High Voltage Connector Assembly is defective. The High Voltage Connector Assembly mounts on the DC Controller PCA and uses spring-loaded pins to contact the toner cartridge.
Replace the toner cartridge, Ensure all covers are in place. Inspect and clean the contacts on the High Voltage Connector Assembly. Closely inspect the primary roller contacts (see Figure 7-2). If damaged, replace the High Voltage Connector Assembly.
4. High voltage power supply circuit is de- Replace the DC Controller PCA.
fective (not supplying the correct negative voltage). 5. DC Controller PCA is defective. If the DC Controller turns ON the laser beam continuously, the entire surface of the Photosensitive drum is neutralized causing a completely black page. 7, Laser/Scanner Assembly faulty (turnino laser on continuously). 8. Connector between the Laser/Scanner Assembly and DC Controller is defective. Replace the DC Controller PCA.
Replace the Laser/Scanner
Assembly.
Replace the Scanner/DC Controller connector,
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Troubleshooting Image Formation Troubleshooting
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Table 7-20 Faded Print POSSIBLE CAUSE 1. Toner supply low, 2. Print Density is set incorrectly, Print Density is adjustable through software, through HP Explorer's Remote Control Panel, or through the front control panel ~LaserJet 4P/4MP). 3. EconoMode is on. EconoMode saves toner by reducing the dot density. This may appear to be a print quality problem in some cases. RECOMMENDED ACTION Shake the cartridge gently to redistribute the toner, or replace the cartridge. Change to a darker setting and retry printing.
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Turn EconoMode off through software, through HP Explorer's Remote Control Panel, or through the front control panel (LaserJet 4P/4MP).
4. Paper does not meet specs. The mois- Try a different paper lot (see `(Media ture content, conductivity, or surface fin- Specifications" in Chapter 2). ish may not work correctly with the printer's electrophotographic process. 5. Transfer Roller is defective or incorrectly installed. If the transfer roller loses conductivity, it cannot effectively pull toner from the drum to the paper. 6. Laser/Scanner properly. door not opening Inspect the Transfer Roller for proper installation and contact. If the Transfer Roller is damaged, replace it. 1. Remove and re-seat the toner cartridge. 2, Check the Laser/Scanner shutter door for proper operation. If defective, replace the Laser/Scanner Assembly.
7. High Voltage Connector Assembly is Check the pins and springs for functionality, If dirty, clean using alcohol; defective. The High Voltage Connector if damaged, replace the High Voltage Assembly mounts on the DC Controller PCA and uses spring-loaded pins to con- Connector Assembly. tact the toner cartridge. 8. DC Controller PCA is defective. The DC Controller supplies the proper voltage to the High Voltage contacts. Replace the DC Controller PCA.
Troubleshooting Image Formation Troubleshooting
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Table 7-21
Vertical White Stripes POSSIBLE CAUSE RECOMMENDED ACTION
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11. Toner cartridge is nearly empty. This can cause uneven toner ciistribution. 2. Toner cartridge has been exposed to too much light. 3. Contaminated Beam-to-Drum Mirror. A dirty mirror will reduce the amount of light that reaches the toner cartridge's photosensitive drum,
NOTE: An excessively dusty environment can allow dust particles to be drawn into the printer, contaminating the Beam-to-Drum Mirror.
Remove the toner cartridge and shake it gently. The cartridge will soon require replacement, Store the toner cartridge in a darkened environment forseveral days. This may restore the photosensitive potential. Inspect themirror. Use filtered, compressed air to clean. If still dirty, clean it carefully using lens cleaner and a lint free cloth or swab. NOTE: If removing the mirror, note its alignment position relative to the mark on the printer chassis before loosening the screw on the right end. If the mirror needs adjustment, refer to the procedure under "Beam-to-Drum Mirror Adjustment" later in this chapter. Remove the toner cartridge and check the laser beam printer slot for foreign objects. Replace the toner cartridge if it is damaged. Remove the Printer Cover and inspect the path from the Laser/Scanner to the mirror, looking for foreign objects in the beam path. Replace the Laser/Scanner Assembly if the lens is scratched.
4, Foreign objects in beam path. Any for-
eign objects will block the light from developing an image on the Photosensitive drum.
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Troubleshooting Image Formation Troubleshooting
Table 7-22
Vertical Black Lines POSSIBLE CAUSE RECOMMENDED ACTION ,0
11. Toner cartridge is damaged.
Inspect the toner cartridge for a scratched photosensitive drum or toner leaking through worn seals. Replace as necessary. or Inspect the Fusing Assembly for toner build-up or scratches on the fuser rollers Try cleaning with alcohol. Replace the Fusing AssemblV if damaged. Remove and inspect (see Chapter 6 for removal procedure). Cleansing compressed air. Replace if damaged.
2. Fusing Assembly is contaminated damaged.
3. Static Eliminator Strip teeth are contaminated or defective.
Table 7-23
Horizontal
Black Lines RECOMMENDED ACTION
POSSIBLE CAUSE 1. Toner cartridge not seated properly. 2. Toner cartridge defective, 3. Repetitive defect. If the lines are repeated at a consistent interval down the page, this is a repetitive defect.
Remove the cartridge and reinserl it. Replace the cartridge. Refer to Table 7-24 (next), as well as the "Repetitive Image Defect Ruler: (Figure 7-9),
Troubleshooting image Formation Troubleshooting
Table 7'-24
Repetitive
Defeck
When troubleshooting repetitive image defects, use the Repetitive Image Defect Ruler, supplied in Figure 7-9 to measure the distance between recurring defects. POSSIBLE CAUSE 1. Toner cartridge is damaged. RECOMMENDED ACTION
The circumference of the photoconductive drum inside the toner cartridge is 75 mm (2.95 inches). If the defect repeats at this interval, the defect is associated with the drum. Inspect the drum for scratches or damage, Replace the toner cartridge. Examine and clean rollers in the paper path (refer to "Cleaning Printer Components" in Chapter 4). The circumference of the lower fusing Pressure Roller is 47 mm (1 .85 inches). If the defect repeats at this interval, the defect is associated with the Pressure Roller, Clean the Fusing Assembly using alcohol. If the problem persists, replace the Fusinq Assemblv. Inspect the gears driving the toner cartridge and the Fuser. Replace the Gear Train Assembly if necessary. Try a different paper lot (see "Media Specifications" in Chapter 2),
2. Dirty Rollers. Any dirty roller in the paper path may result in a repetitive print defect. 3. Fusing Assembly is dirty or defective.
4. Gears are worn, causing slippage or umping. 5. Paper does not meet specs. The sur`ace of the paper maybe too coarse, ~ausing repeated marks.
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Troubleshooting
Image Formation Troubleshooting
Table 7-25
Staining POSSIBLE CAUSE RECOMMENDED ACTION
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1, Printing on wrong side of paper, The label on the ream of paper indicates which side to print on. The different surface properties of some papers may cause problems if loaded wron~ side up. 2, Dirty printer. 3. Dirty Transfer Roller. This problem is characterized by staining on the back of the paper and will not occur unless the Transfer Roller is extremely dirty. 4. Toner build-up in the Fusing Assembly. Toner build-up can physically damage the Fusing Assembly. 5, Toner build-up caused by duplexing. 6. Leaking toner cartridge.
Check for the arrow on the paper wrapper. Be sure paper is loaded with the arrow pointing down in the paper cassette. Clean the inside of the printer as described in Chapter 4. Clean the Transfer Roller using a dry, lint-free cloth.
Remove and clean the Fusing Assembly (see Chapter 6). Either avoid duplexing or clean the printer more often. ReDlace the toner cartridqe.
Try a different paper lot (see "Media 7. Paper does not meet specs. The paper moisture content, conductivity, or sur- Specifications" in Chapter 2). face finish may not work correctly with the printer's electrophotographic process.
Troubleshooting Image Formation Troubleshooting
Table 7-26
Dropout POSSIBLE CAUSE RECOMMENDED Try reprinting the iob. ACTION
1, Single sheet of paper defective.
Try a different paper lot (see "Media 2. Paper does not meet specs. The paper moisture content, conductivity, or sur- Specifications" in Chapter 2). face finish may not work correctly with the printer's electrophotographic proc-
&
3. High voltage power supply defective
Replace the DC Controller. Replace the Transfer Roller.
4. Transfer Roller defective.
Table 7-27
Character
Voids RECOMMENDED ACTION
POSSIBLE CAUSE 1. Bad transparencies. Transparencies can have this problem because they are not designed for proper toner adhesion, 2. Printing on wrong side of paper. The label on the ream of paper indicates which side to print on. The different surface mo~erties of some ~a~ers mav cause p~obiems if loaded wrong side up. 3. Bad paper lot. The surface of the paper may be too smooth or rough for
proper toner adhesion, 4. Bad Transfer Roller. If the Transfer
Use Hewlett-Packard approved transparencies (refer to "Media Specifications" in Chapter 2). Check for the arrow on the paper wraDDer. Be sure Da~er is loaded with the arrow pointing down in the paper cassette, Try a different paper lot (see "Media Specifications" in Chapter 2).
Clean the Transfer Roller using a dry, lint-free cloth, DO NOT touch the transfer Roller with your fingers. If the problem persists, replace the Transfer Roller Assembly.
I
Roller has finger oils on its surface, is dirty or is worn-out, this problem can reSuit.
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Troubleshooting
Image Formation Troubleshooting
Table 7.28
Background
Scatter RECOMMENDED ACTION
POSSIBLE CAUSE
,0
1. Bad Media. The moisture content, con- Try a different media (see "Paper ductivity or surface finish may not work Specifications" in Chapter 2). correctly with the electrophotographic yrocess.
2. Inside of printer is dirty (toner may have leaked out of the toner cartridge). Clean inside of printer (see Chapter 4). Install a new toner cartridge if leaking.
3. Printing on envelope seams. Printing on an envelope seam can cause a background scatter problem, 4. Defective toner carlridcie. 5. Dirty or worn Transfer Roller, A worn Transfer Roller can cause background due to improper bias voltages.
Move the text to an area without seams, If not printing on seams, try a higher print density setting (see item 6, below). Install a new toner cartridge. Clean the Transfer Roller using a dry, lintfree cloth. DO NOT touch the Transfer Roller with your fingers. If the problem persists, replace the Transfer Roller Assembly. Adjust the print density to a higher setting through software, through the Print Quality menu of the HP Explorer Remote Control Panel, or through the front control panel (LaserJet 4P/4MP).
6. Print Density set too low. If the Print Density is set too low, then background scatter can result, particularly with envelopes and heavier papers.
Table 7-29
Bottom Portion of Page Blank POSSIBLE CAUSE RECOMMENDED ACTION
1. Page too complex. The printer can not Set Page Protect to ON or AUTO ,through the HP Explorer Remote Control create the image fast enough to keep pace with the print engine, 2. Not enough memory. The page is too complex for standard printer memory. 3. Printing on legal-size paper when software is specifying letter size. (This will also cause paper jams,) Add printer memory. As an alternative, ~simplify the print iob. Review software selection. Ensure that printing is on selected size.
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Troubleshooting knage Formation Troubleshooting
-raw 7-33
Faulty Registration
Symptoms of faulty registration are print images which are not skewed (parallel to the paper path), but which begin printing (leading edge) either too early or too late. POSSIBLE CAUSE 1. Overloaded paper cassette. If the cassette is overloaded, the Pickup Rollers may not pick the paper up correctly. 2, Paper guide on the paper cassette adjusted too tight. If the guide is pushing too tightly against the paper, it maybe delayed in being pulled into the printer. 3. Paper does not meet specs, The surface of the paper maybe too smooth for the Pickup and Feed Rollers to correctly feed paper into the printer. 4. Registration adjustment is required. RECOMMENDED ACTION
Reload proper amount of paper squarely in the cassette. Review paper loading with the customer. Verify that the paper guide is adjusted for the correct paper size and is locked into position. Note that too loose a setting may cause image skewing. Try a different paper lot (see "Media Specifications" in Chapter 2).
If the top of the page does not begin printing within the proper distance from the leading edge of the paper, then a registration adjustment is required. Refer to "Leading Edge Adjustment," later in this chapter, Replace the defective gear, if available, or the Drive Train Assembly.
5. Worn or broken drive gears. If any gear within the drive train or paper path becomes excessively worn or dirty, erratic paoer movement can result, 6. Worn Pickup, Oblique, and/or Registration Rollers. Paper is not being picked-up consistently.
Inspect all paper path rollers, looking for ~ear, cracks, or glazing. Replace the ~orn rollers.
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Troubleshooting Image Formation Troubleshooting
Table 7-31
Smeared Print POSSIBLE CAUSE RECOMMENDED ACTION ,0
1, Bad media. The moisture content, con- Try a different paper lot or other media (see "Media Specifications" in Chapter 2). ductivity, or surface finish of the media being printed may not work correctly with the electrophotographic process.
2. Dirty Fusing Rollers. Toner build-up can cause the print on a page to smear. 3. The Static Eliminator Strip is dirly or is not grounded, allowing a static charge to remain on the page. 4. Fusing Assembly is defective. The print will smear if the Fusing Assembly is not heated sufficiently to bond the toner image to the paper. 5. DC Controller is defective. The DC Controller regulates fusing roller temperature.
Remove and inspect the Fusing Assembly for excessive toner build-up. Clean using alcohol. Clean or replace the Static Eliminator Strip, Usecompressed airtoclean (see "Static Eliminator Strip" in Chapter 6). Replace the Fusing Assembly,
If a new Fusing Assembly does not resolve the problem, replace the DC Controller PCA.
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Troubleshooting Image Formation Troubleshooting
Table 7-32
Imaae Skew POSSIBLE CAUSE RECOMMENDED ACTION
1. Paper is loaded incorrectly. If the paper is not installed flush into the paper cassette, a skewing problem will result. 2. Bad Paper Lot. Paper that is manufactured poorly or inconsistently, or that has too smooth or too rough a surface texture can cause an imaqe skew problem.
Remove paper from the tray and install paper correctly. Position the paper guide correctly for the paper size being used. Try a different paper lot (see "Media Specifications" in Chapter 2).
3. Worn Pickup, Oblique, and/or Registra- Inspect all paper path rollers, looking for tion Rollers. Paper is not being picked-up wear, cracks, or glazing. Replace the worn rollers. consistently. 4. Beam-to-Drum Mirror adjustment is required. If the mirror has been removed, or the right end mounting screw has been loosened, the mirror needs to be readjusted. 5. Manual feed skew problems. Refer to `(Beam-to-Drum Mirror adjustment," later in this chapter to adjust the image to proper tolerances.
Instruct customer to feed media against left side alignment guide, and not to reinsert once the printer "grips" the media.
Table 7-33
Compressed
Print RECOMMENDED ACTION
POSSIBLE CAUSE 1Toner carlridge bushings are too tight. This may occur on refilled toner cartridges. 2. Broken or worn gear.
Replace the toner cartridge.
Inspect and replace the worn gear or assembly.
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