Canon Pro-1 Vertical banding - Nozzle check OK except for CO

[The Hat]

t's becoming most likely that contamination is the cause - a little cyan ink has got in the CO at some point before it goes through the print head nozzle. The question is where it is happening and what I can do about it.

You could try a test of the CO cart and see if any cyan ink has got inside and that would eliminate any cross contamination issues in the cartridge bay area.

You’ll need one of these to extract a drop of ink from the cart, just cut the metal from the needle and it will then fit into the cart outlet, O’ trim the wings from the edges on the plastic syringe. Hold the cart upside down, makes it easier to get some CO out ..
or this..

Now the only other place you can get contamination from is the print head itself, that’s going to need a lot of soul searching because its either a tubing that has come adrift or a leak where something is broke.

I will see what I can do for you regards some more information to help you deal and gain access to the print head.. PM sent..

 

[Artur5]

After all the information that Dave has supplied I suspect and fear that the problem is inside the printhead. As he suggests, plumbing trouble. Inside the printhead there's a rubber gasket sealing the ceramic plate at the bottom and the plastic body above. ( See below the rubber gasket from a Canon Maxify printhead.). That gasket has a number of holes corresponding each to one color channel, so the ink can pass from the printhead body to the ceramic plate without mixing colors. It's not usual, but sometimes the gasket develops a crack in the rubber and inks from two adjacent channels mix to some extent. If Chroma optimizer contaminates black or cyan, we won't see it, because chroma is colorless, but if it's the other way around, any amount of cyan on the chroma channel will be immediately visible.
As I wrote in other post, my Pro10 suffers from this issue too, although to a much lesser extent than in this case. It needs weeks with the printer sitting idle to see any cyan shade in the band of the chroma nozzle test. Nevertheless, I suspect that, as time goes by, the problem will get worse and eventually I'll have to replace the printhead.

Dave, chroma optimizer is applied by default on glossy/semigloss and luster media. You can select 'Auto': applied everywhere except on blank areas of the image. 'All': chroma is layered on the whole area of the image. 'Custom' : you select the area by creating a pattern where chroma will be applied. I never used this setting, so I can't help. Maybe it's possjble to disable it totally. Other users here will know better.
Chroma is never applied to plain, matte or fine art papers.

 

[dave_n_s]

Onwards we go, focusing on finding the source of contamination and fixing it if it makes economic sense. I'll double check no cyan has found its way back into the CO cartridge. Because air pressure is used to expel ink from the cartridge, it's not impossible that a leak of cyan has allowed it to be driven back into the cartridge. We shall see. After that, it's plumbing or print head. Plumbing is step one - remove sufficient structure to see the feed tubes.

Does anyone have a close-up that shows what I should expect to see - is the CO absolutely colorless or does it have a faint hue of ????? as seen through the tube?

After that, if nothing found it will be print head removal to see if the fluid at the CO port is contaminated, which will rule out the print head if contaminated and point to the tube connections to the interface to the print head. Otherwise it's the print head and a purge will be the last chance hotel to see if this can be cleared without buying a new print head.

Does that make sense?

My only option at this point is to run a system clean first of the group that contains CO & Cyan.

 

[Artur5]

I have the impression that if there’s was a leak somewhere in the tubing between cartridges and printhead, the ink would drop inside the printer instead of finding a way into the tube of another ink channel. For this to happen both the cyan and the chroma tubes should have a leak at almost the same spot. Not impossible, but highly unlikely.

 

[dave_n_s]

I have the impression that if there’s was a leak somewhere in the tubing between cartridges and printhead, the ink would drop inside the printer instead of finding a way into the tube of another ink channel. For this to happen both the cyan and the chroma tubes should have a leak at almost the same spot. Not impossible, but highly unlikely.

I agree. The most likely point outside the print head is the mating face between the print head and the ink supply, but I'm going to troubleshoot in order of least committed ink usage.

That's actually why I considered doing a Group 3 system clean as step one as removing the print head probably uses a pile of ink for all three groups, refilling the lines that it assumes are empty after fitting a replacement head, unless it knows the same head has been replaced.

 

[The Hat]

I agree. The most likely point outside the print head is the mating face between the print head and the ink supply

Here is a partial strip down, but be careful of the many booby traps..

P.S. If stratman was still here he'd have some fun with this thread..

 

[cadbase]

Did you solve this problem?

I have a Canon imagePROGRAF PRO-1000 that started showing a magenta or red cast on the CO but the Nozzle Check pattern is otherwise good. The printer wasn't used for several months, and I also suspect a cross contamination problem at the print head because I've replaced all carts with new OEM ones and tried a couple of cleans plus a deep clean but, if anything, the problem is getting worse.

It makes the printer useless because the cast is evident on all prints. If I switch the chroma optimizer from "Auto" to "Overall" the magenta cast more obvious as it goes across the entire sheet (including the borders outside the printed area).

I've ordered a new CO cartridge in case the existing ink was defective, but I doubt that's the cause because magenta was evident with the cart before that. I can't see any magenta when I remove and inspect the CO cartridge,

One option would be to replace the entire print head, but the money could be wasted if the problem's elsewhere.

I'm wondering if it's possible to access the area where the print head parks for inspection and manual cleaning?

 

[cadbase]

Update: The problem with the CO contamination seems to be getting better and a photo test sheet is now close to perfect.

Thinking that it was a fault in the print head, I forked out AUD 900 for a brand new one. However, installing that made no difference and the Nozzle Check pattern still showed a strong magenta cast on the CO band. There was clearly nothing wrong with the old head and the contamination was somewhere upstream from that - (e.g. somewhere between the print head and the cartridges such as in the tubing).

I spent the next 4 hours carefully cleaning and flushing the old print head with cleaning solution so I can keep it as a spare!

Next, I replaced the recently installed CO cartridge with a brand new one purchased last week in case the chroma optimizer ink had somehow "degraded" in storage.

However, after carrying out a further 2 cleaning cycles, I noticed the grey ink (GY) was now missing from the Nozzle Check pattern. That in turn caused the color calibration sequences to error out.

Another two cleaning cycles fixed the missing GY, but the Nozzle Check still showed magenta on the CO band. However, it seemed to be lighter that before and it had a lower impact on full test card prints.

I suspect that because the CO coating solution is normally clear, it must only take a tiny about of contamination to ruin prints and that needs dozens of deep cleaning cycles and full test prints to properly flush out the system.

So far, I've probably used up one full set of 12 ink cartridges (AUD 850), one print head (AUD 900), two maintenance cartridges and about 50 sheets of A4 photo paper just testing and troubleshooting.

 

[Artur5]

Occasionally I get this kind of contamination on the CO stripes of my Pro10s, but only when the printer has been idle for at least two weeks.

Like you, at first I suspected a leak inside the printhead, but it wasn’t so. Most likely the issue is the residual ink on the resting pads. After one or two weeks being left undisturbed by a cleaning cycle. these inks start to mix between them. CO, being transparent, shows instantly any trace of the other colors. In my case it is cyan that contaminates sometime the chroma band. In your Pro1000 it seems to be blue.

On my Pro10, after one or two cleaning cycles the contamination disappears. Logically, on a Pro1000 it takes much longer because this printer has internal reservoirs between the printhead and the cartridges but, as you’ll see, the issue will clear up eventually.

These Canon printers don’t like to be left alone for more than a couple of weeks, else they start playing tricks on you.

 

[The Hat]

I suspect that because the CO coating solution is normally clear, it must only take a tiny about of contamination

Try flooding the purge pads (Parking station) with window cleaner and then run 1 cleaning cycle, and that should clear up any cross colour contamination..