PDA

View Full Version : Re: Dirty Printouts on a Minolta Di620...


Custom Search


Copycat2
07-22-2008, 11:21 PM
Hello everyone,

I'm getting dirty printouts from a Minolta Di620 B&W engine that's connected. When I say dirty, I'm referring to the faint second or double image that's on the next page from the previous page. There are also ghost images four inches or so below the original image. It almost looks as if the image has been scraped or that fine scratch lines appear near the edges of the sheets. Also, during duplexing, one side is cleaner than the other. It almost looks as if there's a drum problem with the machine.

Could this poor image quality be caused by old developer that's been sitting inside the developer unit for three or four years? I think that there's also a scavenger blade of some sorts inside the developer unit? Could this be causing the poor image quality as well?

I really appreciate anything on this one - as the machine has been sitting for almost four years!

cobiray
07-22-2008, 11:50 PM
If the machine has been sitting for years it will need service to run properly. Sounds like the erase lamp is either very dirty or not working at all. Check the continuity of the lamp, the condition of the cleaning blade and if the blade is in the "shipping" position. Your developer is probably also shot if you've got over all background shading. If you've got dark, random lines the drum and charge components whould be replaced. Hope this helps and good luck.

Jack Reacher
07-23-2008, 07:00 AM
is it a mirror image or a repeat image?

Copycat2
07-23-2008, 07:01 PM
First, I wanted to thank cobiray and Jack for their helpful replies!

To answer Jack Reacher's question about the image being "a mirror image or a repeat image?"...

The image is repeated as a ghost image or lightened image every 4.5 inches. What's above is faintly repeated below on one side and above on the other. This ghost or faint repeated image makes the copy rather "dirty" and unacceptable for my quality-oriented print-for-pay customers.

cobiray
07-23-2008, 09:43 PM
Also, if the image is repeating that in that short a space, you may need a upper fusing (hot) roller and/or a cleaning web. If the non stick coating is worn off or if the web is not cleaning the toner from the roller, toner will stick to the roller and then show up on the same page.

Now that I think about it, the slip clutch and pressure roller on the web unit may be failed also. If you stop the copy process before the toner is fused you can determine where the fault is. If there is no repeated image before it's fused, the problem is the fuser/cleaning section. If the image is repeated before it is fused then the problem is in the drum/developer unit.

Copycat2
07-24-2008, 12:02 AM
This is fantastic, you guys are great!!! I wouldn't know what to fix without your help.

OK, I want to give you a little history of what I already replaced in order to narrow down the next set of parts I'll need to order...

I just replaced the lower heat roller (light brown rubber roller). At the same time, I also replaced the fuser web and the thin orange foam roller for the web. The clutch that allows the web roller to advance but not go back appears to be in good shape - i.e. it seems to work. I didn't replace the upper fuser roller - the dark one with the Teflon (polytetrafluoroethylene) coating because it required some special C-ring or C-clamp tool. Also, it looked as though it might be a tough job - a rather intimidating project, I thought at the time.

I also noticed when I removed the web fuser roller assembly, that's located in a metal case, at the top of the fusing unit, held on by four screws, there is a little motor next to the fuser web advancement gears. Could this motor be the culprit? I think the part is called a WEB MOTOR (part number 9311-3310-21). It seems as though the fuser web is NOT advancing and this little motor could be the cause? I only say this because my new orange foam web roller is starting to develop a flat spot and the web area is VERY dark and full of toner. Is there any way to test the web advancement motor? Also, even if the motor was working properly, would these problems go away? The more I think about it, the more I'm thinking: I should have replaced the upper fuser roller!

Any ideas on this would be GREATLY appreciated.

cobiray
07-24-2008, 02:12 PM
Sounds like the motor may not be turning. Make sure you can advance the web unit by hand easily, as I've had the slip clutch not slip giving the same symptom.

Jack Reacher
07-25-2008, 04:39 AM
Be real careful to put the correct screws back in the lid that holds the web. The little short black screws are the ones you need there otherwise a longer screw will stop the gear turning and sometimes stuff the motor as well. I think my guys put at least 2 or 3 motors in before i went to have a look. The flat spot is not real helpful on the orange roller, depends how bad.

Copycat2
07-25-2008, 05:16 PM
Hi again everyone,

Thanks for the additional suggestions - VERY helpful.

I checked the screws that secure the metal fuser web casing and they're the correct short black "factory" screws.

I've been looking again at the fuser web motor. The little 12V, 2.5W motor that advances the web does so very slowly, perhaps 1RPM? I removed the two little screws that hold it to the fuser unit. It looks as though the shaft holding the little gear can be pulled out - up to 1/4 inch. I don't think this is supposed to move in and out, so I am going to replace the web motor. So, altogether, I am going to replace the following parts:

Minolta Di620 Upper Fuser Roller - MFR PART #: 1075-768
Minolta Di620 Web Motor - MFR PART #: 9311-3310-21
Minolta Di620 Cleaning Blade Kit - MFR PART #: 1074-0904-01

If anyone thinks that I should order anything else, I welcome their suggestions.

fixthecopier
07-26-2008, 01:35 AM
I think you are on the right track, I have changed a lot of those motors. It is real simple, when you take the motor out, if you can rotate the gear forward or backward with your hand, the motor is bad. If you are not sure, take the motor out and rig it to run with the door open, the motor should pulse every 10 to 14 copies and you will see the gear turn. The upper roller is not that hard, just take the lamps out carefully. Count on the plastic clips that hold the lamp wires down to break, you may want to get some. Ialso just fixed the problem you have described. I rebuilt my fuser cause it was worn, but the drum blade stopped the perfect second image of some words about 4 inches apart. Good luck, and you can get a good set of snap ring pliers at sears for about 15 bucks, money well spent.

Copycat2
07-26-2008, 04:45 AM
Hello fixthecopier,

Thank you for the helpful advice on the motor replacement. Based on your description of a "bad" motor, it has seen better days. There is absolutely no resistance when I rotate the little gray gear (either way) that's attached to the shaft of the motor. In fact, it's so far gone that the shaft can be pulled away from the motor housing, up to a 1/4 inch of free play.

Thanks again for another excellent tip: the Sears Craftsman branded tool. Excellent value for the money. I've often wondered why Snap-on tools are three or sometimes four times the price (than their closest competitors). They make some of the best chromed ratchets though!

Now, I'm wondering whether or not I should order a drum as well? Here's an interesting question that could be a post topic all on its own... Whether or not to buy OEM or after-market parts? The OEM drum is almost $700.00 USD but, oddly enough, the after-market drum is only $180.00 USD. Is the OEM or Konica Minolta branded drum that much better? Will the after-market fit and work well, or might it damage the internal components of the developer unit? The answers to these part questions would be an interesting post topic in and of itself. I for one would like to find out if the OEM parts are that much better than the after-market parts.

cobiray
07-27-2008, 12:51 AM
It really depends on what your preference is on parts. OEM parts will fit and work with the equipment they are designed for. Aftermarket parts are suspect sometimes. Also it depends where you get the parts from. I think we used Katun drums in the 520 and 620 models with out and major issues. You may need to do some additional adjustments to get the copy quality acceptable. I don't have any info on any other aftermarket companies, so if you have a company you're looking at you might get a definative response on a specific vendor. It's no different than aftermarket parts in the automotive industry. Some of the parts will work fine, others will fit and perform poorly. Just remember, you usually get what you pay for.

Custom Search