streaks and lines on prints

[wabhughug]

Hi,

I've just been given a L7780 all-in-one and I'm trying to get it working right. I'm using it with an imac G5 using snow leopard OS. I just learned about the webscan which answered my question about scanning an image onto my computer but my big bugbear is the print quality.

I've cleaned, calibrated and aligned the living daylights out of the printer, the heads are described as "ok" but I have a list of complaints I can't find a solution for. When I print directly from a memory card the printer gives its best results but there are faint white streaks across the print about 5 mm apart. When I print via the computer I get distinct narrow lines, usually white, about 2 cm apart.

On the the various test prints when I was doing the head cleaning etc., There was always a white line through text about 5 cm from the top. 

Because these problems are similar in nature but always with the difference between the memory card prints and the computer prints, I don't think it is the heads, alignment or calibration. I'm sure I could be wrong but that just made sense to me. 

Does someone have any big ideas about this.

Thank you for taking the time to read this and thanks for any suggestions.

[yellstr]

Hi

It seems that your printer feeds paper a bit too much between printhead passes. This extra pulled millimeters of paper result in those while lines.

In the HP Utility, there is a function called "Linefeed Calibration", which should fix problems like these.

[Essika]

This may sound silly, but have you checked your ink levels?

Setup menu> Tools> Ink Gauge.

If they are good print the print quality page, chances are it's the printheads.

Setup menu> Print report> Print Quality Report.

If there are lines through all of test pattern 2, calibrate the linefeed

If it is only through certain blocks, you may need to replace a printhead. To determine which one it is, see the chart below:

Black block has lines – replace the Black/Yellow printhead.

Red block has lines – replace the Black/Yellow printhead.

Green block has lines – replace the Black/Yellow printhead.

Figure 14: Streaked black, red, or green color blocks - replace Black/Yellow Printhead

Cyan block has lines – replace the Magenta/Cyan printhead.

Magenta block has lines – replace the Magenta/Cyan printhead.

Figure 15: Streaked cyan or magenta color blocks - replace Cyan/Magenta Printhead

Check the end of warranty date, if it is in warranty, call HP for a replacement and have your troubleshooting steps handy so they know what you have done. If they are out of warranty, check here for replacements and cost.

[wabhughug]

Thanks to everyone who's taken the trouble to reply. I was thinking it may be time to replace the yellow/black printhead. The only thing that cast doubt on that solution and also the others which I had tried before was that I got such very different results printing wirelessly from my imac and printing from a memory card. Has anyone come across this before, please.

Best results were direct from the memory card, only soft, white streaks as opposed to definite white lines across the print when done wirelessly.

[wabhughug]

Thanks to everyone who replied to my posting before but none of the suggestions were any help. I have calibrated, cleaned and aligned and did so before I came here to begin with. The gaps in the printouts suggested I needed a new black & yellow print head so I bought one which did nothing. 

I believe that whatever is wrong with my printer, an officejet pro L7780, isn't in that area. I get very different results when scanning and direct printing to when I print from my computer wirelessly. Faint streaks every 5 mm for direct prints and strong, clear yellow or white stripes when done wirelessly. Why would there be such a difference between the two prints if it was the heads or something like that.

Please can someone come up with a suggestion that is a bit farther on than the cleaning, aligning etc.. Thanks to everyone who is reading this and trying to think it out.