Grid Lines show up in certain print types.

[nonalignment]

HP Officejet Pro 8600 all in one.

Imac OS 10.6.8

When ever I print in black and white mode for any size or type document or when I print in color to a single 4x6 photo page the vertical grid lines show up on the print.  I don't have this problem when I print the same 4x6 color photo on a full size 8x10 page.  I don't have this problem whenever I print any document in color.  I have deep cleaned the print heads and realigned the print heads several times; but I cannot lose the grid lines when I print in black and white and try to print color to the smaller format paper?   I love this printer otherwise.  Setup was easy, operation is user friendly, and it prints beautifully other than these two little annoying instances.  Can anyone offer a solution?

[Daniel_L]

Hello there!

Are you noticing these grid lines when printing from any software, or particular programs?

[nonalignment]

The grid lines appear in everything I print in Black and White.  It does not matter what software program I am using.  I use Word for Mac as my word processing program and every black and white document prints with the grid lines.  If I print in color even though the document is black and white it prints perfectly?  I had printed about 100 prints all on 8x10 paper and they all printed fine.  It wasn't until I switched to 4x6 photo paper that I saw the grid lines.  I use iPhoto as my picture processing program..........I love this printer and its versitility but this has become a minor annonance to say the least..........Thanks Lynn

[Daniel_L]

This may be related to the type of paper being used. You mentioned that when using the 8x10 paper it worked fine. If you go back to 8x10 paper does it still show the gridlines?

[Bobby2012]

I am having the same problem with vertical grid lines printing a color 8 X 10 photo from iPhoto. I haven't tried any other sizes or printing in black and white. I'm using a MacBook Pro and printing wirelessly if that helps. Could the lines actually come from the printer starting and stopping (buffering)?

[nonalignment]

Grid lines show up on any size paper when printing in Black and White.  Prints perfectly in color on any size paper but 4X6. Very frustrating and annoying.  Printer should produce usable print no matter what size paper I'm using; Black & White or Color!