It seems that the printer answers the wrong resolution (firmware bug).
Under the printer's attributes I have found:
DEBUG2: Attr: pwg-raster-document-resolution-supported
DEBUG2: Value: 600x2dpi
Please run the following command:
ipptool -tv ipp://copper.local:631/ipp/print get-printer-attributes.test
> ipp-attrs.txt
and attach the file ipp-attrs.txt to your answer to this bug report. Thanks.
To be able to print for the time being, please edit your PPD file as
follows:
Replace
----------
*DefaultResolution: 600x2dpi
*OpenUI *cupsPrintQuality/Print Quality: PickOne
*OrderDependency: 10 AnySetup *cupsPrintQuality
*DefaultcupsPrintQuality: Normal
*cupsPrintQuality Normal/Normal: "<</HWResolution[600 2]>>setpagedevice"
*cupsPrintQuality High/High: "<</HWResolution[600 2]>>setpagedevice"
*CloseUI: *cupsPrintQuality
----------
by
----------
*DefaultResolution: 600x600dpi
*OpenUI *cupsPrintQuality/Print Quality: PickOne
*OrderDependency: 10 AnySetup *cupsPrintQuality
*DefaultcupsPrintQuality: Normal
*cupsPrintQuality Normal/Normal: "<</HWResolution[600 600]>>setpagedevice"
*cupsPrintQuality High/High: "<</HWResolution[2400 600]>>setpagedevice"
*CloseUI: *cupsPrintQuality
----------
Do not forget to restart CUPS after editing or replacing your PPD file.
Please tell whether this change fixes your problem.
Till