Minolta Dialta Di152 Black Streaks

[Frankie4Fingers]

Hi guys,

I have a Minolta Dialta Di152 photocopier that often, but not always, leaves black streaks on the page. I've attached a PDF to show what it does. When I open the door on the RH side and look at the drum, I can see that it has residual toner on it that matches the black streaks. The drum itself appears to be in good condition.

Can anyone tell me what would cause this situation and what needs to be done to rectify it. Any help and suggestions would be greatly appreciated.

Thanks very much.

Frank.

[wagon]

Most likely a stuffed cleaner blade or a non-functioning waste toner auger.

[Emjay]

Yep - these (and later models based on this series) are notorious for the augers in the waste toner box disintegrating, and then the waste toner section gets totally blocked up, resulting in old toner getting onto the drum etc.

Pull the drum assembly out, remove two screws on the top of the assembly, and two clips, then GENTLY open the toner box cover. It will be packed full of old toner (also stuck to the foam under the lid, so careful where you put it).

On the augers, there should be some clear plastic blades. These usually fall off or get damaged. Also, the gears that drive these augers get stripped very easily.

This assembly is dead easy to dismantle and rebuild once you've done it a couple of times. If the waste toner section is badly damaged, you'll need a complete new drum assembly (excluding drum of course).

The developer section is built better luckily, although I have had gear failure on those occasionally.

Shout if you need any info etc.

MJ

[Frankie4Fingers]

OK thanks very much for the advice, I'll check it out this weekend and see how I go. I'll let you know!

[Emjay]

Just a thought, if you get really stuck, I could take a photo of the waste toner section of the one I have sitting in the workshop at the moment.

[Frankie4Fingers]

Thanks very much for that Emjay, I really appreciate that. I have a repair manual so I'll give it a shot this Saturday with that, if I have any problems I'll get you to take a photo for me. Thanks again!

[Frankie4Fingers]

Hi Emjay, I checked out the Di152 on the weekend. I opened the waste toner lid as you said and sure enough it was very full of old toner. I brushed about half of it out, and I could see that all those little plastic blades were present and looked to be in very good condition. I had a close look on the sides of the unit (I separated the waste toner section from the developer section) and could see several white plastic gears, all of which looked to be in good condition.

Underneath the plastic blades was a long thing that kind of looked like a helical shape, I don't know whether that was supposed to rotate normally but when I rotated the drum a little, it didn't move. When I rotated the drum I couldn't see anything in the waste toner section moving, I don't know if that's normal or not.

Anyhow I didn't want to go any further at that point because I could see nothing obviously wrong so I just put it all back together, hoping that the waste toner I'd removed would help, and believe it or not, it did. It's been copying beautifully since then. I expect the problem will repeat itself again in the future however when more waste toner collects. Do you think I should explore deeper so see if some parts of the waste toner section need replacing?

Thanks very much for your help.

Frank.

[Cantechman]

It could just be excess moisture causing the toner to get packed together a little to tight. At least you know whats causing the problem.

[Emjay]

Nope - you'd be suprised how long they will go for between services. Officially, that entire sub assembly is supposed to be replaced at 40K pages, but more often they just get vac'd out.

I think its a design issue, with a narrow pipe leading between the waste toner collection box, and the dev tank. It's supposed to be moved back to the dev tank, but it doesn't take much to block that pipe (toner getting lumpy due to the environment etc) and everything builds up in the waste toner box.

I still like these little machines though, they are really easy to work on, and produce suprisingly good copies.

[Frankie4Fingers]

Thanks guys, the copier has started making black streaks again. Do you think it might need a new cleaning blade? Or do you think I should just vacuum out the waste toner section? Last time I brushed it out, so maybe 50% was still left there. I'm surprised that the problem has come back so soon!

[tech51]

I would suspect that the small bevelled gear on the end of the recycle auger is not turning when the shaft rotates causing the toner to back up. My cure for this (which normally cures this permanently) is to use a soldering iron with a fine tip to "weld" the gear to the shaft. Just make sure you dont accidentally melt the gear teeth!! Cheers.....

[Frankie4Fingers]

Thanks tech51. Is the auger that long helical-screw-type item that sits under the clear plastic blades? Should you see it turning when you take the waste toner cover off and turn the drum?

[tech51]

Thanks tech51. Is the auger that long helical-screw-type item that sits under the clear plastic blades? Should you see it turning when you take the waste toner cover off and turn the drum?
Don`t think so. How I check it is to hold the auger and turn the gears. If the little bevel gear spins but the auger doesnt, then thats your` problem.

[Frankie4Fingers]

OK. What does the auger look like exactly, and where is it located? I have a parts manual here but can't see anything called an auger in the cleaner section.

[tech51]

Thanks tech51. Is the auger that long helical-screw-type item that sits under the clear plastic blades? Should you see it turning when you take the waste toner cover off and turn the drum?

Sorry Frankie, misread your post. Yes the auger sits under those blades, dont know what they call it in the parts book, it may not be available as a spare. Any way my advice is the same as before, and yes it should turn if the drum is in place....

[minimerlin]

If I remember the so called auger used to snap off at one end and a mod was done to strengthen it! Trouble is I have no idea of the new number..sorry.

[Frankie4Fingers]

Thanks tech51, I think you might be right then because that long black plastic screw-type thing under the plastic blades doesn't move ever when I turn the drum. Is the bevel gear you refer to on the left or on the right as you look at the unit from the drum side?

Thanks minimerlin, I'll also check out whether the auger itself is broken.

[tech51]

On the left

[Frankie4Fingers]

Thanks very much for your help guys, I found the problem. It was actually quite simple, Emjay you were right, the unit is quite straightforward to strip and rebuild.

Inside the waste toner tank there are 2 long things (augers?) and one wasn't turning at all. All the gears were 100% perfect, but the auger with the helix on it, that pushes the waste toner off the left, seemed like maybe it had worn a little on the RH side (the side opposite to where the waste toner is ejected). As a result, it had moved axially to the right and its steel shaft therefore had lost engagement with a little gear on the LH side (this gear keys to the steel shaft via a D-shaped hole, which was in good condition). This little gear is responsible for turning the auger with the plastic flaps on it and the screw in the waste toner ejector chute, both of which were therefore not operating. Kind of explains why I found no toner in the ejector chute!

So all I needed to do was to put a spacer washer on the RH side of the auger with the helix to prevent it moving right and everything seems OK.

Thanks again for everyone's input! Cheers.

Frank.

[Emjay]

I've also seen (and used) SuperGlue on that bevelled gear before now, although I think I'd prefer to use Epoxy Resin of some sort if I wasn't in a hurry.