Saturday, February 4, 2012

Printing!

Alright, so I finally got the machine working. My friend was over helping, and we got a lot done, so there's not going to be many in-progress pictures here.

I fixed the spit cup being broken by using a piece of metal from a computer case, bending it at a 90-degree angle, and mounting it against the plastic piece behind the spit cup, and the spit cup to it, using 3M VHB Foam tape. Really sticky stuff, and I made sure to clean the heck out of all surfaces with 91% alcohol before applying the tape, to make sure it would adhere well. It's been holding just fine so far!


I should add that a large reason that the insides of the machine were coated with ink, that the control panel cable was damaged and the spit cup holder was broken was due to a simple calibration error. The spit cup's position is determined by two limits, specified in the diagnostic menu under "FlushPoint".
You simply hold a piece of paper over the spit cup (or halfway over it, so you can compare the marks easier), have it run a test, and then adjust the left/right limits accordingly. A 3-minute fix would have prevented a lot of work, and it was clear that's where the issue was, as the lip of the cup was wet, indicating ink was not spraying in the right location.


Getting back to reassembly. To start with, we began by getting the rear ink holders reassembled and set back into place. Next, we flushed the lines once more, as in the previous article, since they'd been sitting around for a week or so with solvent in them. Naturally, that was going to break more ink loose, and it did. We just did a quick flush until the line ran clear, then pulled the tank out of the cartridge holder and used the syringe at the head to pull the cleaning fluid out of the line. That way, the initial fill of ink wouldn't be diluted.

With all the ink lines cleaned out and empty, we began the process of installing the print heads. The cables are arranged in a certain way, which are usually clear if you have removed them. The cable going to the right-hand head (when viewing the print head from the front of the printer) is installed first, routed UNDER the head height adjustment bar, then carefully inserted into the slots (both on the top board and on the side of the head. The bends in the cables should help make it clear which way the cables should be inserted into the head and top board. The right-hand head goes into the slot in the top board closer to the front of the printer. The left is installed after the right, cable routed over the top of the other cable, and plugged into the upper slot on the top board. The heads should be inserted very carefully as to not scratch the head surface on the metal carriage.
After seating the head into the slot, install the spring with tweezers, and fasten the washer and screw into the head to keep it in place. You will need to loosen this later during calibration, so no need to crank on it.


Next, we began installing the inks. We opened each cartridge's outer bag and installed it into the slots one at a time. After installing the ink tank, we then installed the brass nut, and the o-ring onto the corresponding hard line (it's a lot easier if you cut off the zip-tie holding the metal lines down to the head), and slid the damper onto the line. Then, lower the brass nut down onto the damper, and carefully (to make sure you don't cross-thread the damper) tighten down the nut onto the damper. We then took the empty syringe, inserted the adapter (just an angle-cut rigid plastic line on ours) into the bottom of the damper (carefully as to not unseat the o-ring), until it made good contact. Then we gently pulled on the syringe to began sucking the ink into the line. After about 10 seconds of suction, and seeing the ink flow through the line, it will begin flowing into the damper and through into the syringe. Pulling the hose quickly out of the damper after the ink begins to flow seemed to help the ink fill the damper.

Then, plug the damper gently into the corresponding peg on the head, while seating the front groove of the damper into the slot on the head carriage.

After filling all inks and installing the dampers in this way (we needed to tilt the light magenta damper backwards to help get it to fill properly, then tilt it back down and install it), the next step is to do a manual fill through the pump. The reason is that since the peristaltic pump does not have any fluid in it, and they are horrible at pumping air, they will not be able to achieve the suction required to pull ink through the head.
What we did is using the same adapter, unplug the rigid line going to the ink tank from each of the hoses, and attach one of them to the syringe. Then, after sliding the head all the way over to the home position, making sure that the rubber had a good seal, we pulled on the syringe. The after a few short seconds, the ink began to come through the line into the syringe, which is plenty. Then, we disconnected the line from the syringe and reconnected it to the drain line. After repeating for the other line, we were ready to power the system up.

The cable routing is a bit of a challenge, and I'll address it later, since I still need to redo the routing.

Now that the lines and heads have been filled, you can go through the initialization procedure and fill the heads, and then work through the calibration.

The hard part of calibration is adjusting the heads in the carriage. The two big things that need to be adjusted are the rotation of the head, and the shift forward-back relative to the other head. These will take a bunch of time and make you frustrated.

Here's a top-down view of the heads so you can see the adjustments. The two round adjusters in the front are to adjust the rotation of the head behind it, and the small adjuster on the side is to adjust the right print head's (viewed from the front) front-to-back movement.

To do these adjustments, you need to loosen the screw holding the head in, adjust it, and then tighten it back up. The frustrating part is once you adjust the rotation, then try to adjust the front-to-back, inevitably, you will mess up the rotation again. it takes time, printing, and patience to get this right. After messing with it for an hour (for the second time) it's mostly aligned, though the left head still has a slight rotation to it.

The loupe helps tremendously, you can see each dot and where it's placed. Helps a lot for the bi-directional printing.

I've also started a Wiki called Mutoh Info. It's hopefully going to be some sort of repository for all the Mutoh information that shows up on the forums and other places, somewhere for information on how to work on these things and how to troubleshoot as well. At the very least, I'll dump everything I know there, and it'll be a little easier than looking through these blogs.

More to come soon! I'm going to get some more pictures up and hopefully we will have this thing doing some nice prints soon!

3 comments:

  1. Awesome work - that calibration sounds like a major pain, but I'm sure the output will be worth it!

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  2. Simple, to the point and very informative....you have shared remarkable knowledge..now i understand and know more about printing process..

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  3. Its really impressive post..your sharing info are adorable..!!
    These are helping me a lot..Scratch cards printing

    ReplyDelete