I have had this problem for a number of years. When I print anything that isn't strictly text (images, documents with letterhead, etc), the printer seems to treat the transparent background as non-white and adds very subtle pixelation. The dots are visible on the printed document. The printer is a Canon Imageclass D1150, and the driver is Canon's UFR II. I've tried every version that has come out over the years with no improvement.

If I set "toner save" to "yes" the pixels are fainter, but they're still visible.

I wonder if your laser printer has a hardware problem rather than a driver-related issue here. The symptoms read a bit like this...

https://www.printertechs.com/printer...ground-scatter

It's definitely software. The pattern doesn't appear if I print from VBox running Windows, and the pattern is clearly deliberate. It's consistent and symmetrical all over the sheet.

Strange. It would be interesting to know if others using the UFRII driver are impacted similarly. Do you observe the same if printing a CUPS test page? Does this happen when printing from all applications?

Unlikely to help, but it might be worth checking print options perhaps (eg media settings)

I have the same problem with my home laser printer that also uses UFR II. The output of lpotions -l is:

Resolution/Resolution : *600
CNTonerSaving/Toner Save : Auto True *False
MediaType/Media Type : *Auto PlainPaper PlainPaperL HEAVY ThickPaperH OHP ENVELOPE
InputSlot/Paper Source: *Auto
OutputBin/Paper Destination: *Auto
CNSpecialPrintMode/Special Print Adjustment: False *Mode1 Mode2
Duplex/Duplex: *None DuplexNoTumble DuplexTumble
BindEdge/BindingEdge: *Left Top
Collate/Collate: *False Group
CNImageRefinement/Image Refinement: *True False
CNHalftone/Halftones : Resolution *Gradation ColorTone
PageSize/Page Size: *Letter Legal Executive A5 B5 A4 Monarch Com10 dl_envelope Envelope_C5

Does changing 'CNSpecialPrintMode/Special Print Adjustment' or 'CNHalftone/Halftones' make any difference?

I tried all the special setting and halftone options.

Can you also answer the questions asked in post #4

The same thing happens with a test page. It happens when printing from any application that uses CUPS

Ok, thanks for the update. I'm out of ideas with this - other than to contact Canon with a bug report.