Trigger 37
Printer Guru
- Joined
- Dec 23, 2006
- Messages
- 607
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I know this subject has been posted a 100 times,... and I've made some of them myself. I've been helping people for years to deal with this problem and have sent out dozens of test files to help other isolate the problem between the printhead and the purge unit. Maybe it was Socraties that said,.."You can learn something new everyday" and WOW how true that is.
I was given a lightly used Canon MX850 printer because the owner could not get it to print BLACK text. I had done the normal process in the printer and checked the ink carts were OK, and did the basic cleaning cycle and printed the nozzle test print. Sure enough it would not print any part of the BLACK Matrix. So I took out the ink carts and the head and did the first step of my normal cleaning by making a "BLOT" test of the head. I do this on a folded wet paper towel that has most of the water rung out. The BLOT test is repeated in about 6 places and this shows me if there is really ink in the printhead. I was especially looking for the black ink and sure enough there it was. In the past I have always told people that if you can see plenty of ink in the nozzles but it will not print,..then the head is probably bad. It is not 100% true,..just most of the time. After all, if there is ink in the nozzles and you try and print you should at least see the image from one, or two, or ten nozzles out of 1000's. So when I saw black ink on the BLOT test I was almost sure the head was bad. Anyway I decided to go ahead with my standard cleaning process using a stream of rather hot water focused on the filter screens and the bottom nozzles. I've done this on at least 100 printers and at first I saw the normal amount of ink spill out into the sink and down the drain. I continue the stream and very soon there was not more colored ink coming out and when I back flushed the head there were no color ink drops on the filter screens anymore. However I continued to see more black ink coming out of the filter screen and when I focused the stream on the BLACK nozzles more ink kept coming out. I kept up the stream and even more ink came. After awhile the ink began to dissapear so I focused the stream directly on the large black filter. A lillte more ink continued to flow so I kept up the flushing. All of a sudden a large flow of black ink drop out the nozzles and then continued on for a considerable time. I kept the flushing up until I was satisfied that I had all the ink out.
The good news is that I dried the head and re-installed the head and ink and did the normal internal cleaning to Prime the head with new ink. The nozzle test was about 90% perfect but their were still a couple of dozen nozzles that were clogged. I took the head out and did my Super Secret Cleaning process and after that the entire head was back to 100% perfect. This printer has now become my primary home Network printer.
What I learned from all of this is that there is still something that none of have observed or understood about the ink resvoir chambers inside the printhead. What was happening to this printhead (and probably many others) is that there was plenty of ink in the nozzles but that the input filter screen and upper channels of the head were clogged with dried up ink. Somehow when that path is blocked or clogged the normal BubbleJet printing does not occur. WHY?????
I believe I know the answer and maybe someday I will run an experiment that will prove it. What happens is that if the filter is totally block then ink can not get in from the ink cart and because of the "Vacuum" process the inkjet Bubble can NOT be ejected if ink can't be free to flow and replace it. It is the same as if we had left the yellow tape on the air intake port of the ink cart. If air can not get into the ink cart to replace the ink that flows,..then no ink will flow.,..and no ink will print. I'm sure most of you have heard many people complain that "My new ink cart won't print" and then they come to find out they forgot to remove the yellow tape that seals the air intake.
Normally clogged nozzles are taken care of by using internal cleaning cycles. We all do this at the first sign of streaks in printing in either colors or black. However, when the input filter screen is totally clogged, there will be no ink flow and no printing. My original set of instructions to isolate this problem between the printhead and the purge unit contained instructions that does test this but I will need to update those instructions to explain the test in more detail.
I am still amazed at how much ink came out of that head. I had already done 10+ minutes of flushing when it first broke loose and then it took another 15 minutes to clean it all. Even after that I found 24 nozzles that were clogged. Wouldn't it be great if we all learned something new everyday.
I was given a lightly used Canon MX850 printer because the owner could not get it to print BLACK text. I had done the normal process in the printer and checked the ink carts were OK, and did the basic cleaning cycle and printed the nozzle test print. Sure enough it would not print any part of the BLACK Matrix. So I took out the ink carts and the head and did the first step of my normal cleaning by making a "BLOT" test of the head. I do this on a folded wet paper towel that has most of the water rung out. The BLOT test is repeated in about 6 places and this shows me if there is really ink in the printhead. I was especially looking for the black ink and sure enough there it was. In the past I have always told people that if you can see plenty of ink in the nozzles but it will not print,..then the head is probably bad. It is not 100% true,..just most of the time. After all, if there is ink in the nozzles and you try and print you should at least see the image from one, or two, or ten nozzles out of 1000's. So when I saw black ink on the BLOT test I was almost sure the head was bad. Anyway I decided to go ahead with my standard cleaning process using a stream of rather hot water focused on the filter screens and the bottom nozzles. I've done this on at least 100 printers and at first I saw the normal amount of ink spill out into the sink and down the drain. I continue the stream and very soon there was not more colored ink coming out and when I back flushed the head there were no color ink drops on the filter screens anymore. However I continued to see more black ink coming out of the filter screen and when I focused the stream on the BLACK nozzles more ink kept coming out. I kept up the stream and even more ink came. After awhile the ink began to dissapear so I focused the stream directly on the large black filter. A lillte more ink continued to flow so I kept up the flushing. All of a sudden a large flow of black ink drop out the nozzles and then continued on for a considerable time. I kept the flushing up until I was satisfied that I had all the ink out.
The good news is that I dried the head and re-installed the head and ink and did the normal internal cleaning to Prime the head with new ink. The nozzle test was about 90% perfect but their were still a couple of dozen nozzles that were clogged. I took the head out and did my Super Secret Cleaning process and after that the entire head was back to 100% perfect. This printer has now become my primary home Network printer.
What I learned from all of this is that there is still something that none of have observed or understood about the ink resvoir chambers inside the printhead. What was happening to this printhead (and probably many others) is that there was plenty of ink in the nozzles but that the input filter screen and upper channels of the head were clogged with dried up ink. Somehow when that path is blocked or clogged the normal BubbleJet printing does not occur. WHY?????
I believe I know the answer and maybe someday I will run an experiment that will prove it. What happens is that if the filter is totally block then ink can not get in from the ink cart and because of the "Vacuum" process the inkjet Bubble can NOT be ejected if ink can't be free to flow and replace it. It is the same as if we had left the yellow tape on the air intake port of the ink cart. If air can not get into the ink cart to replace the ink that flows,..then no ink will flow.,..and no ink will print. I'm sure most of you have heard many people complain that "My new ink cart won't print" and then they come to find out they forgot to remove the yellow tape that seals the air intake.
Normally clogged nozzles are taken care of by using internal cleaning cycles. We all do this at the first sign of streaks in printing in either colors or black. However, when the input filter screen is totally clogged, there will be no ink flow and no printing. My original set of instructions to isolate this problem between the printhead and the purge unit contained instructions that does test this but I will need to update those instructions to explain the test in more detail.
I am still amazed at how much ink came out of that head. I had already done 10+ minutes of flushing when it first broke loose and then it took another 15 minutes to clean it all. Even after that I found 24 nozzles that were clogged. Wouldn't it be great if we all learned something new everyday.
