Pixma MP970 colors are off

[PeterBJ]

I checked the service manual for the MP970. This manual has no table of which inks are used with different settings. The service manuals seem to consist of two or three parts, the service manual, a technical reference chapter and sometimes an appendix. The table of ink use is normally found in the technical reference which is missing from the MP970 manual. A table of ink use is found in the more complete manual for the smaller iP4200 that has fewer ink cartridges and nozzles. It is a different printer but maybe the ink usage pattern is similar?

Service manual and parts catalog in one file for the MP970 is found here. The more complete service manual for the iP4200 is found here.

Added: The iP6600D use the same dye cartridges as the MP970 but has no pigment black. Maybe its ink usage is more similar to that of the MP970? You find a service manual for the iP6600D including a table of ink usage here. The table is found at pages 2-5 and 2-6 in the manual.

 

[mikling]

@mikling Yes, there was little use of color printing during the last half-year or so. I also have to admit that I did print sometimes with C, PC and/or PM empty... I print mostly on regular paper.
Can the prolonged soaking in a window cleaner damage somehow its ability to print pigment black? Even if it won't work as a photolab eventually, I still want to use it as a regular printer for texts etc. while it's working at all.

Admitting to print with C empty will likely point to why the C is now missing or not functioning properly now. I would try and soak and also use some cleaning cartridge until you get good pattern out of all colors. If the C reappears and looks somewhat like BK, and further soaking does not help, then you can re initiate printing and hopefully it will smooth back out.

My next response will show why the PC and PM was spared the fate of the C.

 

[mikling]

I checked the service manual for the MP970. This manual has no table of which inks are used with different settings. The service manuals seem to consist of two or three parts, the service manual, a technical reference chapter and sometimes an appendix. The table of ink use is normally found in the technical reference which is missing from the MP970 manual. A table of ink use is found in the more complete manual for the smaller iP4200 that has fewer ink cartridges and nozzles. It is a different printer but maybe the ink usage pattern is similar?

Service manual and parts catalog in one file for the MP970 is found here. The more complete service manual for the iP4200 is found here.

Added: The iP6600D use the same dye cartridges as the MP970 but has no pigment black. Maybe its ink usage is more similar to that of the MP970? You find a service manual for the iP6600D including a table of ink usage here. The table is found at pages 2-5 and 2-6 in the manual.

PeterBJ, thanks for the links to the service manual. The ink that is used for different media is shown on page 45. My hunch was correct in that if plain or copy paper is used, then only CMYK is actually used. This aspect spared the nozzles or drying of ink inside the nozzles when the printer was used but PC and PM was empty. As we see, the C was not spared the fate of printing without ink and its consequences.

As an aside. Many think of the difference between standard printing and high quality to be the resolution. Well the native resolution of printing is actually the same as shown in the table. Take a look at Photo Paper Pro. Now notice that the kand Y resolution is held to be 600x1200 but the other 4 colors are 600x2400 in both standard and high quality. So what makes the high quality a better image....the next line. The number of passes. The dots are interleaved during passes. In standard mode the printer uses apparently 6 passes to complete printing but in high quality it uses 8 passes. The more passes the more interleaving and the more potential for unique spray patterns thus the potential to print more colors and more accuracy when colors are interpolated. What is interesting is that it in custom mode it uses 16 passes! That is significant! and it is only deployed on Photo Paper Pro. ( This is the significance of the print engine)

What this tells me is that in standard printing, the true number of colors that can be printed is actually less than in high quality. This will affect the smoothness of gradations especially in the lighter colors. It may affect the number of microdots but it certainly affects the steps in color resolved on a gradation. Now that "custom" setting with 16 passes might actually be great for very light tones and its smoothness of gradations. Notice that Canon it looks like only triggers this 16 passes mode in Photo Paper Pro.
I wonder as well if the gamut volumes Canon specs for the printer is in the custom mode.....interesting.

One day I'll play with this on my Pro9000MkII to see what happens. I have to admit I have never used custom settings. it will be interesting.

 

[Dracus]

@PeterBJ thank you for the manuals!

Admitting to print with C empty will likely point to why the C is now missing or not functioning properly now.

Yes, even though I knew of the warning, I was seriously ignorant of the real danger and thought it wasn't a big deal. Now I got bit by my ignorance.

My hunch was correct in that if plain or copy paper is used, then only CMYK is actually used. This aspect spared the nozzles or drying of ink inside the nozzles when the printer was used but PC and PM was empty. As we see, the C was not spared the fate of printing without ink and its consequences.

But then PC and PM would not be wasted when printing on regular paper, which was not the case when I had to print color-heavy images on copy paper. I only rarely print photos, but I had to replace PC and especially PM several times.

 

[mikling]

Yes, a normal procedure of the printer is to periodically perform a head cleaning or repriming the nozzles, this process consumes ink from ALL of the colors at the same time. So despite PC and PM not used for printing on plain paper they are still consumed during maintenance, thus they are also consumed by even monochrome black printing to ensure that the nozzle in the color channels do not dry out. i.e periodically flushed.

 

[mikling]

Well I checked my technical manual for the Pro9000. The 9000 does not have that high a number of passes. Other thing is that it has only 2pl droplets but 6144 nozzles versus the 3000+ of the 970. In standard mode it uses a totally different print engine as well. Not comparable at all.
However, the 6600 can print as high as 9600x4800 versus the 4800x2400 max of the 9000.