shaddow on color printing

[adb2]

I have a CP1525nw color laser.  Suddenly, when I print in color with any software, there is a light black shadow on each letter.  Black letters are still very sharp.  Several months ago the printer said I needed a new black cartridge.  I have not installed it yet and didn't plan to until the black color failed.  As I said, black printing is fine.  Could the old black cartridge be causing this somehow?  The shadow is always a light black.

Any other ideas?  As I said, it happens is any software I use, including email.

[Phreding]

Greetings,

Unfortunately I’m not a Print Quality expert but I’ll do my best to help.

First, are you absolutely certain the shadow is black toner?  If possible, use a magnifying glass to look at the tiny dots around the color letters.  When mixed together, Cyan, Magenta and Yellow can appear to look black (or a very dark purple).

Does the shadow follow a certain color pattern?  Try 100% cyan letters, 100% magenta letters and 100% yellow letters.  Do each color have the same shadow?

How far from the letters does the shadow appear?  Does the shadow seem to be shaped like the letter?  Is the shadow present over the entire sheet of paper?

As an experiment, install the new black toner cartridge.  Does the shadow go away?

[adb2]

It is black ink and is what we used to call a drop shadow.  It is a reproduction of each letter printed at about a 25% screen roughly 1/32 of an inch below the actual letter.

[Phreding]

Based on the information so far, it sounds like a black color plane registration issue.  Let’s start by printing the diagnostic page.

1)      Place 2 sheets of white paper into the paper tray.

2)      Using the front panel on the printer, select “Reports->Diagnostic Page”

3)      Look at the second printed page and focus on the black boxes.  Is there a white gap (about 1/32 inch) between the black boxes and the color boxes?  What edge of the black box has the white gap?

If there is a white gap AND it appears above or below (as you hold the paper in portrait orientation) of the black boxes, then please try calibrating the printer.

1)      Using the front panel on the printer, select “System Setup -> Print Quality -> Calibrate Color -> Calibrate Now” menu item. 

2)      The front panel will display “Printing Document” followed by “Calibrating…” and it will make noise for a minute or two.

After the printer stops making it’s printing noises, try printing your test files again.  Did this change the placement of the shadow?

[adb2]

You hit it right on the button!!  It worked perfectly.  Thank you, very much.

[adb2]

I'm afraid I spoke too soon.  The drop shadow is still there.  I ran it through the process a second time with no improvement.

Again, the black cartridge has been "very low" for a month or more representing probably 250 printed pages.  Could a worn out black cartridge be contributing?  I have a new cartridge I was planning to install after the printer stopped printing black, but I would be willing to install it now if there is a good chance this would solve my problem.

By the way, I still think you are great.  Your response has been very prompt, and I respect that.

Art

[Phreding]

Again, I’m not a print quality expert, but from my experience a cartridge that is running low normally does not impact the color plane registration.  For confirmation, I emailed the lead cartridge engineer for that printer and expect a quick response.  If you’re not opposed to opening the new cartridge, you could try it as an experiment.  It may yield surprising results.  If the shadow still appears, it is possible to store an open cartridge for a lengthy time period -- as long as some precautions are taken. 

[adb2]

I will wait a bit to see if you hear back from your cartridge expert before I exchange the black cartridge.  I leave for a month's trip overseas on Monday.  I would like to get this solved before I go, if possible.

[Phreding]

Expert Response:

I spoke to the cartridge and print quality engineer for your printer.  He has experienced color plane registration problems when the toner cartridge gets so low that the printer can no longer “see” (sense) the toner on the transfer belt.  However, as you describe, your black text is sharp and saturated so we suspect this is not the issue.

Background Information:

Now comes the unfortunate news… the HP R&D (Research and Development) group spends a tremendous amount of money, time and engineering effort to automate the correction of color plane registration.  This is required because each engine operates in different environmental conditions and the printer must have the ability to correct tiny mis-alignment issues.  If it doesn’t, “shadows” (mis-alignment) make the image look blurry.  Thus there is very little customers can do to correct the issue outside of forcing the printer to re-calibrate.

Next Step:

For us to make a positive diagnosis and offer the best advice, we need more information and a print sample would improve our understanding the most.  Is it possible to scan (or take a close-up picture) the diagnostic pages and post the files?  An example page showing the “drop shadow” would also help.  Seeing the actual images will help us determine the root cause.

I do apologize for the inconvenience and I’m certain you’ll be busy planning your trip this weekend.  I do hope you can make some time to provide the images and we’ll do our best to get you a timely answer.

[adb2]

Sending you a pdf file of the diagnostic pages as well as a sample of the drop shadow is not a problem.  What is the email address for me to use, or how do I attach it to a message sent to you through this correspondence we are having?  By the way, this morning I unplugged the printer and had it set for several minutes to try to reset the machine, and I then went through the process of correcting the registration without success.  Actually, I tried several times.

However, your comment about there being not enough black toner for the machine to sense it makes me think that changing the cartridge is certainly worthy a try.  I will certainly let you know the results, good or bad.