Ink Refill

Summary of findings on refilling Canon BCI-6 cartridges.

 Misc information

• Some people say that with the availability of low cost non-OEM carts that there is no longer any reason to refill Canon inkjet carts.  There is some validity to this argument, depending on the value that you place on your time and your willingness to tolerate the extra effort required to refill carts.  It is not the purpose of this discussion to debate the merits of this argument.  It IS the purpose of this discussion to discuss alternate refilling methods that may function better than existing techniques for those who are inclined to refill their own carts.
• Based on measurements of the inside dimensions of a dissected non-OEM cart, the “Ink Chamber” has a capacity of 6.4 CCs.  The “Sponge Chamber” has a capacity of 9.6 CCs up to the top of the upper sponge, without accounting for the loss of capacity due to the sponge and filter.  This gives a maximum total capacity of 16 CCs.  One non-OEM box claims 15 CCs, which is reasonable if they completely fill both chambers with ink, which many suppliers don’t.
• The “bottom sponge” has a volume of 5 CCs, and this sponge is usually still almost full when the ink chamber empties.  Since Canon recommends replacing the cartridge at this point to keep from running out of ink (the printer keeps sending warnings), a completely filled cart will only give 10CCs of usable ink.  Most of the new carts that I have seen will only give about 7-8CCs, judging from how much of the upper sponge is empty when they are new.
• It is today’s prevailing wisdom that these carts can only be refilled a limited number of times before something happens to the sponge (it dries out?) that prevents the cartridge from operating properly.  I have listed some other possibilities that could also cause this problem:
  • The “filter” may not always drop back down to its proper position when the cart is removed and may not make good contact with the ink pickup on the print head when the cart is reinserted.  This can be fixed with a few sharp taps of the cartridge onto a hard surface.
  • The “fluid link” between the filter and the bottom sponge is lost.  It is not guaranteed that ink will flow through this interface unless the interface between the two parts is kept filled with ink.  If this interface “dries out” for some reason, the cartridge can be full of ink and still not deliver any ink to the filter.  To check this, blow into the vent opening on the top of the cart with the exit hole uncovered (after making sure that there is no sign of any ink on the vent opening) – use about ¼-½ of the pressure used to blow up a balloon.  Ink should drip out of the exit – at least 1 drop/second.  If ink doesn’t start to flow almost immediately, the filter is being starved for ink and may not be delivering enough ink to the print head.  Blow into the vent with about ½ of the pressure used to blow up a balloon until the ink starts to flow.  Note that the sponges and filter can develop quite a resistance to the ink flow and they will often “push back” some air when you stop blowing into the hole.  This can cause “blow back” you will sometimes see ink pushed back out of the vent when you stop blowing – be careful not to get any of this ink on you.  After using this procedure, let the cart drip for a few minutes, then dab away any excess ink at the exit and vent before putting the cart into the printer.  It is best to wait 20 minutes or more to let the pressures fully equilibrate before using a refilled cart.
  • Air is getting into the bottom sponge – some air naturally enters the sponge each time a cart empties, and it is not removed during a conventional refill procedure.  This can be seen by simply comparing a new cart to one that has been refilled several times.  As more and more cells fill with air, the internal surface tension link between adjacent cells of the sponge can be broken, causing the ink supply to first decrease than eventually stop completely.
  • Most people throw the cart away when it exhibits any of these symptoms and replace it with a new factory filled cart.  This isn’t too much trouble if the factory filled cart uses the same ink formulation as your bulk refill ink.  If the inks are different and you are concerned about the quality of your colors, however, you really need to switch back to factory filled carts in all locations until you get enough empty carts to refill, then you can switch to refilled carts until you run out of empties again, then….. To minimize the number of times that you must make this switch, there are a few techniques that can be used to extend the useful life of your refilled carts.  A few of these procedures are discussed below.

• It has been stated that if the viscosity of an ink is too high that this will cause an ink supply problem, and that the problem ink can be diluted with distilled water as a remedy.  This may fix a flow problem, but it will probably also noticeably change the colors that are printed.  See (“http://www.nifty-stuff.com/forum/viewtopic.php?id=65&p=4”) for a discussion and demonstration of the potential color problems that this can cause.
• There are a number of other strange problems that can occur when the print head is starved for even a single color (“http://www.nifty-stuff.com/forum/viewtopic.php?id=103”).  There are various theories why this happens, but they remain to be proved or disproved.  In any case, the best solution is to never run out of ink!  The main concern about running out of ink is usually said to be that you can permanently damage the print head.  There are examples where this has happened, but it doesn’t seem to be a common occurrence.  The most common problem that I have seen or heard about is that it can take 5 or more “cleaning cycles” to get the ink flowing again, and you can easily lose ¼ of the ink in each cart each time that this happens ($24 of ink with Canon carts – ouch!).   I once inadvertently forgot to fully latch the Green cart into the print head, and it took 5 regular cleanings and a deep cleaning to get the ink flowing properly again, in addition to the 5 cleaning cycles that I ran before discovering the unlatched cart.  Thank goodness these were refilled carts, as I lost almost ½ of the ink in the carts because of a single careless mistake.
• Some people recommend refilling a cart when it still has 6 mm of ink left in the ink chamber.  This means that they have to periodically pull each cart to see the ink level, since the printer’s “out-of-ink” sensor only senses when the ink chamber is empty.  In these cases, the cart should be quickly put back into the print head if it doesn’t need to be refilled.  If the cart needs to be refilled, it should be replaced with a cart containing the same ink and with sufficient ink for at least one cleaning cycle.  This will prevent the ink pickup on the print head from drying out or pulling in air.  The printer sometimes senses or otherwise decides that a cart has been changed and runs an automatic cleaning cycle to pull the new ink into the print head, so every cart that is put into the printer needs to have enough ink to prevent air from being pulled into the print head by a cleaning cycle.  The ideal solution is to have at least 2 carts of each color on hand at all times so that a full cart with the same bulk ink is always ready and can be used to immediately replace the empty cart.
• If you are concerned about the color of your prints, always use a complete set of carts from the same supplier, or use refilled carts with bulk ink from the same supplier.  Inks are formulated to work together and mixing inks from various sources can easily upset the color balance of your prints.

Alternative filling techniques to help to remove air from the sponge

• Several alternative refill techniques have already been posted at (“http://www.nifty-stuff.com/forum/viewtopic.php?id=28&p=6”).
• The photo below shows how the needle can be sealed to the refill hole using some “tacky putty” that is available at hobby stores.  By SLOWLY pushing ink into the cart with the injection hole sealed, additional ink can be pushed into the sponge chamber (and hopefully into the sponge).  Make sure that the needle doesn’t touch bottom of the ink chamber so that the large part of the needle is tight against the cart to prevent the putty from being forced down into the fill hole.  The vent hole must be open and the exit hole sealed during this procedure to prevent ink leakage.  Hold the cap on the exit tightly in place by hand or with a strong rubber band.  Lift the needle slightly to break the seal and fill the rest of ink chamber when you are done pushing extra ink into the ink chamber.
• The next two techniques use vacuum to remove most of the air from the cart and then let the vacuum pull ink into the evacuated cells in the sponge.  This may be the way that new carts are filled, judging by the ink patterns on the top sponge.  It is very possible that one of these (more complicated) techniques will only be necessary every 3^rd or 4^th refill to get the air out of the sponge, and that conventional techniques will suffice for the other refills.  Note that only the two vacuum techniques that showed promise are shown – there were at least 50 other attempts that failed.  You are encouraged to experiment on your own to see if you can develop improvements.  Be forewarned that these techniques can be a little messy until you get the hang of them.
• Both techniques need some extra equipment if you want to try them:
  • You will need a vacuum pump and a vacuum chamber.  A low cost vacuum pump can be made using your car’s engine and a short piece of vacuum hose.  Most gasoline engines will pull at least a 20” vacuum at idle (30” is a “perfect” vacuum).  The problem with using a car engine as your vacuum source is that it has such a high capacity that it pulls its full vacuum on a cart almost instantly, and the ink foams uncontrollably.  The air flow could be controlled with some needle valves and monitored by a vacuum gauge, but a better solution is a simple hand powered vacuum pump.  This type of pump is sold to bleed brakes and was purchased at Sears for $35.  It comes with a gauge, hoses and assorted attachments.  It is rated at up to a 25” vacuum, but it can actually develop slightly more if you pump long enough.  There are more rugged (professional grade, rebuildable) pumps available at auto parts stores for about $80 if you plan on using this pump a lot.                                                                      
  • The previous photo also shows the top of a simple “vacuum chamber” – an empty pickle jar.  You want a wide mouth jar with thick glass and a metal lid capable of withstanding the pressures involved.  Punch a hole in the lid and enlarge it so that a fitting can be roughly screwed in (in this case, a ¼â€ pipe x ¼â€ barbed hose fitting).  Seal the fitting (both inside and outside of the lid) with silicone sealant and let it cure for 24 hours.                                             
  • If you come up with a better solution for a simple vacuum chamber, pass it on (a pressure cooker won’t seal against a vacuum).  Just remember that a large volume takes longer and is more work to pump down.  On the other hand, a larger chamber would allow multiple carts to be refilled simultaneously.  Note that the seal material on the pickle jar lid was designed for a one-time use, and that it will eventually compress with repeated use, so you may have to tighten the lid progressively harder to get it to seal.  When this happens, apply the same silicone sealant used to seal the fitting in the lid as a thin, uniform coating on the seal surface (allowing 24 hours to harden before using).
• Vacuum technique 1:
  • Fill the ink chamber of the cart about 3/4 full, leaving the ink chamber refill home open.
  • Place some duct tape over the vent opening over the sponge chamber to prevent air from being pulled directly into that chamber when the vacuum is released.  Duct tape has a much more aggressive adhesive than scotch tape, but the surface needs to be completely dry and you need to put a lot of pressure on the tape to get a good seal to the top of the cart.  If the vent leaks, the sponge may not fill properly.
  • Seal the exit hole (e.g. using the caps that come with a new cart, held on by a strong rubber band).  If you have some of the new InkGrabber cart holders that were shown in the forum, they appear to be ideal for this use.
  • Mount the cart in the vacuum chamber so that it is held in its normal vertical position – a piece of modeling clay works well for this.  It is also a good idea to put some clay under the jar so that it doesn’t roll around and tip the cart over.
  • With the cart generally level, slowly pull a vacuum on the jar.  This clip shows a (somewhat shaky) demonstration of this process where the vacuum was pulled fast to keep the clip short.  As the vacuum is pulled, the air in the sponge chamber bubbles up through the ink.  When the vacuum is pulled slowly, the walls of the ink bubbles have time to get thinner, more of the ink bubbles have time to break and there is less ink lost to the bubbles coming out of the open injection hole than if the vacuum is pulled quickly.  When a car engine was used to pull the vacuum, almost all of the ink bubbled out of the cart within a few seconds because the vacuum was pulled so quickly.  My guess is that about 2-3 CCs of ink are lost to the ink bubbles with the hand pump – too much if we can only add 4-5 CCs of new ink.  Note the color of the sponge as the vacuum is pulled – it turns white, indicating that most of the ink has been removed.  Toward the end of the clip, it appears that some ink is pooling in the bottom corner of the sponge.
  • The next step is to release the vacuum to pull the ink in the ink chamber into the sponge, shown in this clip.  Tip the jar so that the cart is angled by about 45 degrees so that all of the ink will easily feed into the sponge and then slowly release the vacuum with the trigger on the vacuum pump designed for that purpose.  As the clip shows, the ink is very quickly pulled into the sponge.  It also shows that there is not nearly enough ink in the ink chamber to fill the sponge.
  • The photo below shows the cart after the refill cycle.  It is obvious that all of the ink in the ink chamber was pulled into the sponge.  It is also obvious that most of the ink ended up at the far end of the cart, not at the bottom.  To be a workable solution, it needs an external ink reservoir to draw from so that the ink will completely fill the cart in a single step when the vacuum is released.  This will also require a larger vacuum chamber to accommodate the increased height of the external reservoir.  I did not pursue this solution any further in favor of the second vacuum technique.  It is left open if someone else wants to pursue it.                                                                  
• Vacuum technique 2:
  • Use the same pump and jar as in Technique 1.
  • Keep the refill hole closed and sealed, and tape over the vent using duct tape as above – sealing the vent is very important to get a complete fill of the cart.  This technique works even without adding a refill hole on new carts.
  • Leave the exit hole completely open.
  • Put the cart in a shallow, narrow tray that is slightly longer than the cart – shown below.  In this case, the “tray” is a piece of clear plastic “blister pack” used to package 3 molly anchors (found at Target).  It’s not perfect, but it was the best that I could find on short notice.  If anyone finds a better product for this purpose, please post it.  This tray needs to:
    • Hold at least 20 CCs of ink after the cart is in the tray.
    • Fit in the vacuum chamber.
    • Support the cart in a vertical position (scotch tape worked OK for this tray).
    • Support the cart so that the exit touches the bottom of the tray to pick up as much ink as possible, but at a slight angle so that the exit isn’t sealed against the bottom of the tray.
    • Be stable so that it doesn’t tip over – some modeling clay worked well in this case also.                                                 
  • Fill the tray with enough ink to completely fill the cart (15 CCs minus your estimate of how much ink is already in the cart), plus a few extra CCs.  Almost of the ink that is in the cart will be pulled out when the vacuum is pulled, and will be sucked back into the cart when the vacuum is released, so this ink must be accounted for to prevent overflowing the tray.
  • Slide the tray and cart into the jar, with the tray being tipped slightly toward the cart’s exit so that the ink will run toward the exit as the cart fills.
  • Pull the vacuum.  The degree of bubbling/foaming of the ink will depend on the ink.  The black foamed very little, but the other inks foamed quite a bit.  The photo below was taken while filling a photo magenta cart, and it shows quite a bit of foaming (the poor focus is because the camera focused on the jar, not the cart).  One of the main benefits of this approach is that there is a lot of surface area available to allow the foam bubbles to collapse without overflowing the tray, allowing the vacuum to be pulled more quickly without any loss of ink.  If the foaming starts to get out of control, wait a few minutes for the foam to collapse, then continue.                                            
    
  • Once you are at full vacuum, let everything sit until bubbles stop coming out of the exit – it can take a while for the sponge to release all of its trapped air, and it is important to remove as much of this air as possible.
  • Slowly release the vacuum, as shown on this clip on a PM cart.  Note that the ink bubbles collapse first, then the cart fills with ink.  When finished, the sponge chamber should be full of ink, but the ink chamber may not be as full.  Most of the remaining air in the sponge chamber apparently gets pushed into the ink chamber, preventing it from filling completely.  This can be minimized by:
    • Pulling as high of a vacuum as possible before refilling.
    • Making sure that the vent hole is well sealed before starting.
  • The photo below shows the PM cart that was refilled in the video clip.  The sponge and even the space on top of the sponge are completely filled with ink (the ink above the sponge was eventually absorbed into the sponge).                
  • If this fills the sponge too far for your liking, it is easy to pull a lower vacuum on future carts, and this will pull less ink into the sponge chamber.
  • Unseal the vent, and clear the vent channels (low pressure compressed air is fine for this).  Some ink should drip from the exit when this is done.
  • If you want to “top off” the ink chamber:
    • Seal the exit hole.
    • Open the refill hole
    • Top off the ink chamber as usual and reseal.
    • Remove the exit seal and let the cart sit until it stops dripping.
  • You can save the left over ink in the tray if you wish, but with the cost of bulk ink being so low, even a 50% loss isn’t that bad if this technique reduces your ink feeding problems.  Because the ink is pulled into the cart through the discharge hole in this setup, it is important to keep the ink clean to prevent contaminants from getting to the print head pickup.
  • With a slight modification, this technique can be used to remove the ink that remains in carts if you are changing ink suppliers or if a cart is being refilled for the first time and a different ink was in the cart.  This clipshows 3 carts being emptied together, with a PC cart toward the camera:
    • The 3 carts were tied together with a rubber band and placed into the jar.
    • The exits were open and the vents were sealed.
    • The jar was tipped so that the exits were slightly lower than the rest of the cart.
    • A full vacuum was pulled, pulling the ink from all 3 carts at the same time.
    • It is very important to tip the jar up to a vertical position before releasing the vacuum to prevent the mixed inks from being sucked back into the carts.
    • This procedure will not completely remove all of the ink in a single step if there is a lot of ink left in a cart’s ink chamber, and the procedure may not need to be repeated once or twice in that case.
    • There was a lot of foaming of these 3 inks.

Summary

I have now refilled 6 carts using the second vacuum technique, and each of those carts has been “sucked empty” prior to refilling.  Normally, this would be the kiss of death, but each cart that was refilled in this way printed without problems.  It is still too soon to make any firm statements about the long term success of this technique.  Others are welcomed to give it a try and see what they find.  The best way to see if it works is to take a cart that you consider to be “dead” and refill it according to these instructions.

 Misc Notes

• After a plastic refill syringe is used a number of times, it can become stiff and hard to move, making it difficult to control the ink’s injection rate.  You could suck some oil into the syringe to lubricate the seal, but this would contaminate the ink on the first few refills.  A better solution is to lubricate the seal from the back side by inserting a Q-tip that has been dipped in vegetable oil into the open end of the barrel.  It will be necessary to slightly bend the Q-Tip so that the end contacts the inside of the barrel, then rotate the barrel so that it is coated on its full circumference.  Pull the plunger out to get oil onto the seal surfaces, and then work it in and out to coat the rest of the barrel.
• Refilled carts slowly “dry-out” as some of the ink evaporates through the vent.  This is why new carts are packaged in a sealed bag with the vent sealed.  To minimize the evaporation loss from your spare carts that are not currently installed in the printer, place a wet paper towel in the bottom of a plastic food storage container and store all of your opened carts in the container with the lid sealed.  When the towel starts to dry out, add some more water.  The water in the towel will evaporate and keep the air in the container at 100% RH, slowing the evaporation of water inside the carts stored in the container.  Carts should always be stored with the vent up, just as they are installed in the printer.