Text preview for : 08 - 430Chapter_6.pdf part of Hewlett Packard DesignJet 430-450C-455CA Service Manual



Back to : 01 - 430Front%20Page.pdf | Home

6

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-1

Print Quality Troubleshooting Checklist
When faced with a Print Quality problem, use the following checklist as a guide in troubleshooting the problem: 1 Problem reproduction D Reproduce the problem that the customer is seeing using their original settings. 2 Printer configuration: D Print Mode: Set to Best" (in the printer and in the drivers). D Select the correct media setting when loading the media. 3 Hardware check list
D

Check if the latest version of the firmware is installed. If not Install the latest firmware revision.

4 Cartridges Cartridge Troubleshooting Process: D If you don't have any samples yet, reproduce the original problem with the correct printer settings. D Print the Print Quality Plot using the exact settings and Media that the Customer used when faced with the Print Quality problem ' page 6 3. Cartridge Alignment: D Perform the Cartridge Alignment procedure (details ' User's Guide). 5 Media D Make sure that you use HP or HP approved media. D Select the correct media type through the front panel when loading it. 6 Driver print quality configuration: To clarify if the reason of the problem is related with the print mode defined with the Non HP Driver try the following: D Print the same sample using the Non HP driver and their normal media. D Print the internal demo or print the Print Quality Plot (details ' page 6 3) using HP Media and configuring the printer as indicated previously. If the output obtained using the HP Solution is good and the one obtained through the 3rd party solution is bad, HP support organization should:
D

Communicate to the customer that the problem is not in the printer and that he should address it through the 3rd party vendor support structure.

7 Accuracy Calibration (details ' Chapter 5) D Perform Accuracy calibration" using HP Matte Film.

6-2

HP DesignJet 430, 450C and 455CA Printers

Print Quality

Print Quality Plot
Introduction Whenever a Print Quality problem appears, it is advisable to print the Print Quality Plot to help diagnose the problem. The Print Quality Plot will help you differentiate between possible cartridge errors and other problems such as incorrect front panel selection, driver or RIP configuration or mechanical problems. To achieve the best performance from the printer, advise the customer to only use genuine HP accessories and supplies, whose reliability and performance have been thoroughly tested to give trouble free performance and best quality prints. Using the Print Quality Plot 1 The size of the Print Quality Plot is A3 and B so you must use media (roll or sheet) that is this size or larger. 2 Use the same type of media that the customer was using when the Print quality problem was discovered. 3 Study each of the test patterns in the order listed to determine the type of Print quality problem. 4 If the customer was reporting problems of Print Quality using non HP media and after the Print Quality Plot test the same quality problems appear, advise the customer to use genuine HP media. Repeat the Print Quality Plot test using genuine HP Media. Printing the Print Quality Plot 1 Before printing the plot, in Normal mode, set the Media Type and Print Quality on the front panel to the settings that you want to test. 2 Load a sheet of media in portrait orientation. 3 When the Ready LED lights up, press the Form Feed and Media Source keys together. The Ready light begins to flash, and the media moves slightly forward. The carriage moves to the right side of the Printer, and the fan turns on. The Printer plots the print-quality plot and ejects the media. 4 Unload the media.

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-3

Print Quality Plot The print quality plot for the HP DesignJet 430/450C/455CA is represented below. Use a 10X magnifier to help identify plot quality problems.

Test 6

6-4

HP DesignJet 430, 450C and 455CA Printers

Print Quality

Analyzing the Print Quality Plot The Print Quality Plot will contain six patterns as follows: 1 Cartridge Warm Up (See below). 2 Nozzle Print Test (See below). 3 Vertical Line Straightness Test ' page 6 7. 4 Color Alignment Quality Test ' page 6 9. 5 Color Variation Test ' page 6 11. 6 Banding Test ' page 6 12. Test Pattern 1: Cartridge Warm up This pattern warms up the cartridges, leaving them in a perfect operating condition. You can ignore this pattern and continue with Test Pattern 2.

Test Pattern 2: Nozzle Print Test In this test all the 96 nozzles of each cartridge are tested. For each of the 4 colors you will see the numbers 1 to 90 over the diagonally stepped lines in increments of 5. These numbers correspond to the nozzle number that prints each step. There are two cartridge nozzle errors (see Figure 1): Nozzles not printing. D Nozzles misdirected.
D

Figure 1
Print Quality
HP DesignJet 430, 450C and 455CA Printers

6-5

Nozzles not printing (Nozzles Out) 1 If the diagonally stepped lines are broken in one or more steps it indicates that this specific nozzle(s) may be blocked and are not printing. Nozzles misdirected If all the stepped lines are visible in the pattern, then all the cartridge nozzles are printing. However the nozzles could still be misdirected, possibly due to some dried ink around the nozzles. 1 In the top pattern, marked with numbers, if the diagonally stepped lines are not equally positioned in every step it indicates that this specific nozzle(s) may be misdirected.

Nozzles Problem 1: Nozzles Problem 2: Corrective Action:

Some cartridge nozzles, in any one color, are not printing. Cartridge nozzles are misdirected in any one color. Try the following steps: 1 Prime the Cartridges and print the Print Quality Plot again to see if there has been any improvement. 2 If the error is still present, replace the failing cartridge and print the Print Quality Plot again. 3 If the error continues try the following: D Replace the Trailing Cable ' page 8 8. D Replace the Carriage Assembly ' page 8 37. D Replace the Electronics Module ' page 8 13. Only replace one component at a time and check if the problem has gone before replacing another component. Using this procedure you will be able to determine exactly which component failed.

6-6

HP DesignJet 430, 450C and 455CA Printers

Print Quality

Test Pattern 3: Vertical Line Straightness Test Vertical line straightness is a measure of the horizontal distance between the segments of a vertical line plotted in two consecutive swaths. If the Printer is working correctly, this distance should be less than 2 mils (see Figure 2)
Swath Printing Direction Swath (n1) Swath Printing Direction Swath (n) Swath Printing Direction Swath (n+1) Maximum allowable VLS Error = 2 mils.

Figure 2 Customer Expectations Although the VLS specification satisfies the expectations of most customers, some may complain even when the Printer is working within this specification. If the VLS error is already less than 2 mils, do not try to improve it. The VLS error is composed of two parts (see Figure 3): Theta Zeta error D Bidirectional error
D

Figure 3
Print Quality
HP DesignJet 430, 450C and 455CA Printers

6-7

Bidirectional Error You can see an example of a bidirectional error in Figure 3. If you print the same plot using a unidirectional print mode, the error should not appear. This error can occur for various reasons, including: Incorrect distance between nozzles and media. (Adjustment ' chapter 5.) D Encoder strip slots are damaged or dirty. D Dirt on the pulley is causing the belt to slip. D Friction between carriage bushings and slider rod:
D

Theta Zeta Error You can see an example of a Theta Zeta error in Figure 3. They appear when the rows of nozzles on a cartridge are not perpendicular to the carriage axis (Y axis). This error can occur for various reasons, including: Badly seated cartridge. D Faulty cartridge. D Faulty carriage.
D

Figure 4
6-8
HP DesignJet 430, 450C and 455CA Printers

Print Quality

VLS Problem: Corrective Action:

If the line is not perfectly straight at Bias 0 in the test image (see Figure 4). Try the following steps: 1 Perform the Cartridge Alignment Calibration (Details ' Users Guide) using genuine HP media then print the Print Quality Plot again to see if there has been any improvement. 2 If the problem continues perform the Accuracy Calibration (Details ' page 5 2) and print the Print Quality Plot again to see if there has been any improvement. 3 If the error is still present, replace the failing cartridge and print the Print Quality Plot again. 4 If the error continues try the following: D Replace the Trailing Cable ' page 8 8. D Replace the Carriage Assembly ' page 8 37. D Replace the Electronics Module ' page 8 13. Only replace one component at a time and check if the problem has gone before replacing another component. Using this procedure you will be able to determine exactly which component failed.

Test Pattern 4: Color Alignment Quality Test Upper Test: The first of these patterns tests alignment between the cyan and magenta cartridges; it should be blue with no cyan or magenta shadows. The second tests alignment between the cyan and yellow cartridges; it should be green with no cyan or yellow shadows. The third tests alignment between the magenta and yellow cartridges; it should be red, with no magenta or yellow shadows. Lower Test: This test pattern is to check the color alignment, and produces 6 patterns each with 2 different primary colors. In each pattern you will see primary color circles. If there is misalignment between the primary colors the composite color will be present in one part of the circle and white will be visible at the opposite side of the circle. There are two types of misalignment (see Figures 5 and 6): Horizontal when the misalignment is in the horizontal axis. D Vertical when the misalignment is in the vertical axis.
D

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-9

Figure 5

Figure 6

Alignment Problem: Corrective Action:

Third color present/misalignment in either the boxes or circles of the test image (see Figures 5 & 6). Try the following steps: 1 Perform the Cartridge Alignment Calibration (Details ' Users Guide) using genuine HP media then print the Print Quality Plot again to see if there has been any improvement. 2 If the error is still present, replace the failing cartridge and print the Print Quality Plot again.

6-10

HP DesignJet 430, 450C and 455CA Printers

Print Quality

3 If the problem continues perform the Accuracy Calibration (Details ' page 5 2) and print the Print Quality Plot again to see if there has been any improvement. 4 If the error continues try the following: D Replace the Trailing Cable ' page 8 8. D Replace the Carriage Assembly ' page 8 37. D Replace the X axis Assembly ' page 8 23. Only replace one component at a time and check if the problem has gone before replacing another component. Using this procedure you will be able to determine exactly which component failed.

Test Pattern 5: Color Variation Test This test produces four boxes; black, blue, cyan and yellow. In each box there are two horizontal bands, the lower band is 100% shade, the upper band is shaded from 100% scaling to 60%. The purpose of this test is to determine at what percent the upper shading becomes visible from the lower band. The best way to do this is to cover the box with a piece of paper and slide the paper horizontally across the box. Stop as soon as you see a different shade in the upper box. You can then determine the percentage scaling from the figure at the top or bottom of the box.

Figure 7 (Correct)

Figure 8 (Incorrect)

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-11

Variation Problem:

Corrective Action:

If the upper box shading is never visible or is visible at a very low percentage, it is an indication that the cartridge is producing incorrect size ink drops (see Figure 8). Try the following steps: 1 Replace the failing cartridge and print the Print Quality Plot again. 2 If the error continues try the following: D Replace the Trailing Cable ' page 8 8. D Replace the Carriage Assembly ' page 8 37. Only replace one component at a time and check if the problem has gone before replacing another component. Using this procedure you will be able to determine exactly which component failed.

Test Pattern 6: Banding Test This Test pattern is a long dark stripe and is NOT numbered on the Print Quality plot. It can be found on the left hand side of the other test patterns. Symptoms Random dark or light bands in area fills. There are two types of banding: Negative Banding This means that consecutive swaths overlap each other, creating dark bands. D Positive Banding This means that consecutive swaths do not touch, thus leaving a small gap between each other. This then causes white (or lighter) bands.
D

Figure 9
6-12
HP DesignJet 430, 450C and 455CA Printers

Print Quality

Cartridge Fault D A nozzle is blocked or faulty and is not firing ink drops. D The ink drops of one nozzle are of smaller volume than those of the other nozzles. D A nozzle's ink drop volume varies while plotting. D A nozzle's ink drops are misdirected: D Defect in manufacture of cartridge. D Dirt or debris on the nozzle plate. D Ink puddling on the nozzle plate.
D

An electrical contact is misaligned or damaged on the cartridge, so that it doesn't make correct contact with the circuit on the carriage. (See ' page 4 12, w Carriage Test.)

Printer Fault D Incorrect swath advance angle of the drive roller. This could be caused by a: D Faulty roller (irregular roller radius / defective bearings) D Media axis inaccuracy (defective media motor or driver circuit / calibration lost)
D

D D D D

An electrical contact is faulty in one of the Printer cartridge chutes, so that it doesn't make correct contact with the circuit on the cartridge. (See ' page 4 12, w Carriage Test.) Nozzles touch the service station, thus causing puddling to occur on the print head. Some of the small slots on the encoder strip are damaged. Therefore the Printer cannot position the carriage correctly during cartridge servicing. Cartridges are misaligned with respect to each other. Calibration values lost or incorrect.

Media Fault Some types of media have a coating that prevents them getting wet" from the ink drop. The ink doesn't spread out sufficiently around the point where the dot is placed. Banding may not occur on some poor quality media, where it is counteracted by another problem: large dot gain. This is where the ink spreads out excessively on the media around the desired dot position. To accurately test for banding, use HP polyester inkjet film.

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-13

Banding Problem: Corrective Action:

If there is negative or positive banding in the test image (see Figure 9). Try the following steps: 1 Perform the Cartridge Alignment Calibration (Details ' Users Guide) using genuine HP media then print the Print Quality Plot again to see if there has been any improvement. 2 If the problem continues perform the Accuracy Calibration (Details ' page 5 2) and print the Print Quality Plot again to see if there has been any improvement. 3 Remove the all Cartridges and clean the flex contacts on the Carriage and the Cartridges. Reseat the Cartridges and try the test again. 4 If the error is still present, replace the cartridges and print the Print Quality Plot again. 5 If the error continues try the following: D Replace the Encoder Strip ' page 8 15. D Replace the Trailing Cable ' page 8 8. D Replace the Carriage Assembly ' page 8 37. D Replace the Electronics Module ' page 8 13. Only replace one component at a time and check if the problem has gone before replacing another component. Using this procedure you will be able to determine exactly which component failed.

6-14

HP DesignJet 430, 450C and 455CA Printers

Print Quality

No Printing Defects Found in the Print Quality Plot If all the test patterns from the Print Quality Plot are correct and you still experience print quality problems, here are some of the other causes to check: The print mode used in your printer is incorrect (this is defined by the printer's front panel menu selections). D Non HP driver. D The RIP (If you are using one). D The software applications you are using.
D

Refer to the User's Guide for further information on how to configure the system with correct settings.

Media Always make sure that the customer is using the appropriate media for the required image and that it is consistent with the software application being used. To ensure color accuracy and print quality performance of the printer, only media types that have been certified for the printer should be used. Use of non HP media or HP media not certified for the the printer may significantly reduce the color and print quality of the required images. For details of HP media, refer to the User's Guide or the Media Guide. To have accurate colors, the media settings must match the type of media loaded in the printer. If the customer is using non HP media with HP drivers, the colors in the required print may not be accurate. Advise the customer to use HP media if they want to improve the accuracy of the colors.

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-15

Print Quality Defects Troubleshooting
STARWHEEL MARKS On some drawings (for example, CAD drawings having a thick lined frame around them) on some types of media, you may notice some small marks made by the starwheels. These cannot be avoided. UNEVEN FILL DENSITY Symptoms Blotchy area fills. Product Fault D An incorrect media type setting has been selected on the front panel and does not correspond to the media being used. Media Fault The ink is incompatible with the media and does not spread uniformly through the area fill. Solutions One or both of the following actions may be appropriate to solve an uneven fill density problem: Change the media type setting on the front panel. D Use a more suitable media type. D Replace the faulty cartridge(s). D If the problem is occurring in black area fills on color plots printed in Normal print quality mode, then use Best print quality mode instead.
D

SPRAY Symptoms Smaller dots of sprayed ink located around the point at which the required dot is placed. Product Fault The cartridges are positioned too far from the media. Solution Check the carriage to media distance. (Details ' chapter 5.) Replace the faulty cartridge(s).
6-16
HP DesignJet 430, 450C and 455CA Printers

Print Quality

BLEEDING, BLOOMING AND WICKING Symptoms Blurred lines. (See also ' User's Guide, chapter 9.) Bleeding: Different color inks, printed side by side, run into each other. D Blooming: Ink absorbs into the paper, spreading beyond the desired ink dot. D Wicking: Ink spreads along a fiber or fibers in the paper, creating a spider web" effect.
D

Product Fault Printing in fast mode. Media Fault D The ink is incompatible with the media type. D Environmental conditions may affect the media. (Temperature or humidity levels are too high.) Solutions One or more of the following actions may be appropriate to solve the problem:
D D D D

D

Change the plot quality mode: Plotting in Best mode slows plotting but improves quality. Use better quality media. If you are plotting on vellum or translucent media, try using Hewlett Packard media. Recommended environmental conditions for optimum plot quality are in the range of 15 35 degrees Celsius (59 95 degrees Fahrenheit) with 20 80 % relative humidity. Pen problem: TTOE (Thermal Turn On Energy) has not been performed because of incorrect cartridge change. With the power ON, open the top cover and reseat the cartridge.

INK SMEARING Symptoms Ink smears on the media. (See also ' User's Guide, chapter 9.) Product Fault The media touches the print heads. This can occur because: The media holding mechanism is not holding the media correctly, and the media buckles. D The carriage to media distance is too small. (Adjustment ' chapter 5.)
D

Print Quality

HP DesignJet 430, 450C and 455CA Printers

6-17

HUE CHANGES Symptoms Changes of hue are noticed when printing in color. Cartridge Fault One or more of the print cartridges is running out of ink. (Typically the inks of the four cartridges are used at different rates.) Solution Replace the print cartridge with a new one.

6-18

HP DesignJet 430, 450C and 455CA Printers

Print Quality