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Test Prints
This appendix illustrates the test prints produced by the print engine. It also illustrates a number of defective prints and the reason for the defects. The topic "Printing and print quality problems" on page 47 discusses solutions to the problems shown in this appendix. Consumables Print consists of four 25% tint primary color bands and "gas gauges" for each consumable. Service Print 1 prints out four 25% tint full page fills, each page one primary color. Service Print 2 produces a 1200 dpi test print, a solid red fill prints and a 600 dpi test print.
From the Help Pages menu in the front panel, select Consumables Page
Consumables page <-----> Print
Toner
Black OK Page Remaining: >500 @ 5% coverage Your average coverage/page: TBD%
Power Error
Magenta
=
OK Cyan OK Yellow OK
Page Remaining: >500 @ 5% coverage Your average coverage/page: TBD%
Page Remaining: >500 @ 5% coverage Your average coverage/page: TBD%
Page Remaining: >500 @ 5% coverage Your average coverage/page: TBD%
Imaging Unit
Life Remaining
0% Count (Pages) Serial # Avg. Toner Coverage/Color Date Installed 50%
%
Main Charge Grid
Life Remaining
0% Count (images) 50%
%
100%
100%
Fuser
Life Remaining
0% Count (Pages) Serial # Avg. Toner Coverage/Color Date Installed 50%
%
Fuser Roll
Life Remaining
0% Count (Pages) 50%
%
100%
100%
Transfer Kit
Life Remaining
0% Count (Pages) 50%
%
100%
From the Help Pages menu in the front panel, select Service Print 1
Service Print 1 <-----> Print
Power Error
=
Consumables Print
Black
Black Cyan Magenta Yellow From the Help Pages menu in the front panel, select Service Print 2
Service Print 2 <-----> Print
Cyan
Magenta
Yellow
CMYK
Power Error
=
3102-36
Service Guide
103
Single color mottled or with non-uniform density streaks. If a single color displays a mottled appearance or if a single color shows many vertical streaks of varying densities, then that color's toner cartridge is running of toner. Replace the cartridge.
104
Phaser 740 Color Printer
Vertical line or scratch in print, single color If the scratch is of one missing primary color, then the trouble can usually be traced to a scratch in the developer roller of the missing toner's toner cartridge. No toner is transferred from the developer roller to the photoconductive belt at the defect point. Vertical line or scratch in print, all colors The problem may be caused by contamination on the laser window where the laser beam exits the laser scanner and enters the imaging unit. Since the blocked laser beam cannot discharge the portion of the photoconductive belt it cannot reach, toner will not transfer to those portions of the belt. Consequently a blank, vertical line will appear on the prints in all colors. Remove the imaging unit and, with a squeeze bulb, blow any dust or toner off of the window (located in the "ceiling" of the cavity left in the printer once the imaging unit is removed). If it is in all colors then the problem may be in the imaging unit, such as a scratched photoconductive belt. Replace the imaging unit. A very thin, white line could be caused by a scratched roller in the fuser which replacing will solve. The scratch in the print may not be continuous but rather a set of in-line vertical scratches. Inspect the fuser roller and the print. If the scratches are about 12.1 cm (5 in.) apart and match the defects on the print, then the problem is a scratch on the fuser roller. Replace the fuser. Lastly, a protrusion of some kind in the paper path could be scratching the print.
Service Guide
105
Dark vertical line in print, single color If the line is of one primary color, then the trouble can usually be traced to a defect in the color's toner cartridge. Too much toner is transferred from the developer roller to the photoconductive belt at the defect point. Vertical line in print, all colors The problem may be caused by a dirty main charger, a defect in the fuser or a defect in the imaging unit.
Small, repeating light dot in one color This can usually be traced to a dent-like defect in the developer roller of the toner cartridge in question. The dents should be 3.4 cm (1.5 in) apart or 2.5 cm (1 in.) for 1200 dpi printing. No toner is transferred from the developer roller to the photoconductive belt at the defect point. If the spots are about 12.5 cm (5 in.) apart, then the problem is a defect on the fuser roller. Replace the fuser. In some instances, the spots may be dark instead of white. They may also be shaped something other than round. Refer to the topic "Repeated spots or lines on print in-line with each other" on page 49. It discusses causes of repeated spots based on the distance between the spots.
106
Phaser 740 Color Printer
Single light, horizontal line in all the prints This is probably caused by a defective photoconductive belt onto which toner will not transfer. Replace the imaging unit.
Large, random light smudges Spots such as those illustrated are caused by fingerprints on the photoconductive or accumulator belt. Often, the smudges will gradually fade with additional printing. Alternately, the imaging unit will have to be replaced. Fingerprints can be removed by applying some toner (any color) to the fingerprints and rubbing lightly with a cotton-tipped swab. Don't remove the toner. The printer will remove the toner with its cleaning blade. Remember not to expose the imaging unit to ambient light for more than a minute.
Service Guide
107
One or more dark vertical line in all colors This can often be traced to a dirty scorotron charger (main charger) corona wire. Contamination (dust or toner) interferes with the flow of electrons from the wire to the photoconductive drum. Toner is then transferred to the area of low electron charge and consequently to the accumulator belt and finally the print. Remove the scorotron charger from the imaging unit and clean the charger's corona wire. Replace the scorotron charger, if necessary. If this fails to correct the problem, replace the imaging unit.
Faded, pale prints The imaging unit is old or has been exposed to too much room light. Replace the imaging unit. If printing is weak on paper only, the printer may be printing in transparency mode. Check to see if paper was picked from a transparency tray or if the multi-purpose tray is set for Transparency. Check to see if the Color Calibration menu is set to print lighter. The high-voltage board is not outputting sufficient voltage to the second bias transfer roller, causing poor transfer of toner to paper. Likewise, low voltage to the toner cartridge will cause insufficient transfer of toner to the photoconductive belt. The beam from the laser scanner is weak and is not properly exposing the photoconductive belt. Poor laser exposure results in the negative charges remaining on the photoconductive belt instead of being "erased" by the laser beam, thereby retarding toner transfer from the toner cartridges. Replace the laser scanner.
108
Phaser 740 Color Printer
Dark, vertical streaks and smears on the entire page This is usually due to the accumulator belt toner waste bin being filled and spilling out on the belt. The spilled toner is then being transferred to the print. Most prominent in the middle of the print and in the yellow band. A defective cleaning blade could also cause this. In either case, replacing the imaging unit should fix the problem.
One primary color faded or pale OR a single color has a dark vertical streak This indicates a problem with a single toner cartridge. Replacing the toner cartridge should fix the problem. If it does not, there may be a problem with the toner cartridge selector/eject unit. It may not be pushing the cartridge quite far enough to make proper contact with the photoconductive belt, resulting in poor toner transfer. Replace the toner cartridge selector/eject unit. Lastly, poor electro-mechanical contact my be the problem, although this usually shows itself as light, horizontal streaks and lines. Replace the toner cartridge biasing assembly.
Service Guide
109
Single white spot appear in the same place on the print This indicates a bad spot has developed on the imaging unit's photoconductive belt which will not transfer toner. The imaging unit must be replaced. If the spot appears to migrate vertically from print to print then the defect is on the imaging unit's accumulator belt. In either case the imaging unit must be replaced.
Contamination of one color by another This is most noticeable on solid primary fills. This is caused by a defective photoconductive cleaning blade. The blade is not scraping off all of the untransferred toner from the previous pass of the photoconductive belt to the accumulator belt prior to the next toner's transfer to the photoconductive belt. Replacing the imaging unit corrects this problem. Rarely, a sheet of paper can become folded and jam in the imaging unit, smudging the image.
110
Phaser 740 Color Printer
Interpreting Service Print 2
1
2 3
Service Print 2 is useful for evaluating the condition of the imaging unit. Three prints are made: a 600 dpi print, a solid red fill print, and a 1200 dpi print. With a properly functioning imaging unit and printer, you should see the following:
1. Diagonal lines. These two lines should
4
be smooth and unbroken.
2. Crosshairs. A thin white crosshair
5
should be visible in each block square. As the photoconductive belt ages and fatigues, the crosshair in the top box will disappear followed in time by the lower crosshairs. The belt may "rejuvenate" after a few hours of non-use, but this will only last for a few prints before fatigue sets in again. Fine parallel lines. Distinct parallel lines, both horizontal and vertical, should be viewable. No mottling or blending should be seen. All vertical lines should be identical in appearance and thickness to their horizontal counterparts. 2 pt. text. The 2 point text, the smallest printed on the test print, should be easily readable. Registration. Thin horizontal composite black lines will show misconvergence if each pass of the accumulator belt does not properly register with each pass of the photoconductive belt. Blended fills. The fills should be smooth and even in both the primary and secondary color fills.
6
3.
4. 5.
3102-35
6.
Service Guide
111
Interpreting Service Print 2's solid red fill print The second of the three prints made when Service Print 2 is selected is a solid red fill. Its purpose is to reveal repeating defects that can be traced back to defects on the printers belts or rollers.
1. Look for repeating defects inline down the
print. Refer to the topic "Repeated spots or lines on print in-line with each other" on page 49. It discusses causes of repeated spots based on the distance between the spots. In some instances, the spots may be dark instead of white. They may also be shaped something other than round.
112
Phaser 740 Color Printer