Ricoh 2090/Gestetner 9002 very faint copies

[crystalsound]

Hi guys, I'm a technician and I've discovered only now this wonderful forum. It's always a great pleasure to share and compare our experiences, I hope to be useful for you. Now I have this maybe old machine, a Gestetner 9002/Ricoh 2090, the issue is,as title says, it prints very faint copies. Actually I have not done any kind of maintenance or fix attempts to this machine. First of all, the copier has approx. 1.500.000 copies, don't actually know if the drum is the original one, or if somebody has changed it,and eventually when. I know for sure that the previous technician has changed the developer - don't know if he has put the correct one, type 21 as the service manual says - and the copier has worked quite well for a month. The customer says that it was even too black,at the beginning. But then, it started again to fade, with the actual result of a very light grey printing, although the image looks perfect. I'm going first of all to replace the developer with a new and clean one, but, as this is the first time I work with this machine, I'm looking for any further suggestions about anything I could do to get this machine fixed, service calls, spare parts or anything else. Thanks to everybody

[crystalsound]

Sorry for double posting. Admins may delete the other topic I opened. Sorry

[crystalsound]

Some updates of today: I approached today for the first time to the machine, first copies are almost totally white. Readings are VSP=VSG 5.0v. Thinking of an Id sensor dirty/defective, I try to switch to pixel mode count, but still light copies. Then I start SP2207 002 and sp2962, and something is printed out. I force toner supply with sp2207 001 4 or 5 times, and toner is printed, still a bit light, but it's a result. I started printing copies and after 40-50 copies I get SC495 (toner bottle error). Turn off, turn on again, print 100 copies, getting lighter and lighter. now VSG is 0.2 and VSP still 5.0. Tried to force toner again, but with no results, copies gets lighter and lighter. I'm thinking this machine has at least 2 problems, the first at toner bottle connections (maybe both), the second at ID sensor. Took a look to SC history, the most frequent are SC350-51-52-53 and SC310-311, all quite recent. I hope to get now some good tips to get this machine fixed. Cheers

[peterxu256]

Some updates of today: I approached today for the first time to the machine, first copies are almost totally white. Readings are VSP=VSG 5.0v. Thinking of an Id sensor dirty/defective, I try to switch to pixel mode count, but still light copies. Then I start SP2207 002 and sp2962, and something is printed out. I force toner supply with sp2207 001 4 or 5 times, and toner is printed, still a bit light, but it's a result. I started printing copies and after 40-50 copies I get SC495 (toner bottle error). Turn off, turn on again, print 100 copies, getting lighter and lighter. now VSG is 0.2 and VSP still 5.0. Tried to force toner again, but with no results, copies gets lighter and lighter. I'm thinking this machine has at least 2 problems, the first at toner bottle connections (maybe both), the second at ID sensor. Took a look to SC history, the most frequent are SC350-51-52-53 and SC310-311, all quite recent. I hope to get now some good tips to get this machine fixed. Cheers

It is time to physically check Toner Transportation Path which is very very long path from rear left bottom to front right bottom. First Check starting point Toner Supply Bank, see if Toner scattering around corner ground, or back cover below the Display screen, Put V(x) value aside, the symptom initially came from toner leaking, afterward "toner near-end alert pop up very frequently(toner blocked the sensor).

[crystalsound]

Well, I didn't expect to reply once again, but now I do it.
The actual state of the art is that I changed drum with a new compatible a294 type, new cleaning blade, brush and corona wire. Vacuumed the whole machine that was starved of toner come out from waste toner collection bottle. I found toner everywhere, even in the optics. All filters, quenching lamp, corona grid and wire, etc., were full of toner. Unfortunately I'm not able to get a type 21 developer in acceptable time, so I can't change it right now, but as far as I have seen, it looks like there is not much developer inside the dev unit, disassembling the hopper I can see the inside of the dev unit. But still, the machine now is printing quite good. Values have come back to Vsp 3.80-4.20, vsg 0.30 - 0.60, but vt is quite low, 1-1.50v. Cleaning entrance seal (recovery blade) of the drum has 4 or 5 breaks, it's not in good conditions, as well as mylar seals in the cleaning blade bracket. Prints look quite good, copies too, the problem is that if I print more than 10-15 copies it comes out with some ghost images of the previous prints, approx. 1,5cm of distance (don't know if I'm clear). Let's say, in a grey background characters already printed below are now white impressed. I made a jam myself and drum would look quite clean, but i'm going to confirm it tomorrow. Looked inside the drum unit, quenching lamp is quite dirty once again, only on one side, as well as the top of the cleaning blade, dirty only on one side. There shouldn't be toner there, however. Another point does not convince me is the cleaning roller below the transfer belt. It has some toner melt along itself, I cleaned it with alcohol, not very thoroughly because I was not that sure, but still. Actually what I can say for sure is that the increasing value of Vsg, and consequently light copies, in my case, were caused by the plate that grounds together drum and developer unit, were you put a screw and the drum knob. Well, if it is not correctly inserted, even some millimeters, copies begin to fade inesorably. As soon as you push it towards the inside, first become immediately better. I hope I will be helpful, and I Hope you will be for me too. :P
P.s. This machine is in these condition because it has never had any PM.

[Bantams]

Sounds like the Toner Sensor on the side of the hopper needs replacing possibly due to the previous tech blowing it when he changed the Dev.

[crystalsound]

I'm thinking more and more that the problem is drum-related. I'm reading now some pages I've printed, in 90 pages only 3-4 of them have ghosting, at the beginning of the job, although I have to say I printed it 25 by 25 pages. I can find some words in white and a grey background in some spots of the page, and those words are of one or two pages before. I mean, or the drum isn't being discharged (led strip is quite dirty I've noticed), or cleaning blade isn't doing its job correctly (I didn't have setting powder, I used waste toner) or even it's a ground problem. Sometimes I still get vsg higher - and prints lighter - but I still didn't manage to figure out how to verify drum grounding correctly. Any suggestions?

[peterxu256]

Well, I didn't expect to reply once again, but now I do it.
The actual state of the art is that I changed drum with a new compatible a294 type, new cleaning blade, brush and corona wire. Vacuumed the whole machine that was starved of toner come out from waste toner collection bottle. I found toner everywhere, even in the optics. All filters, quenching lamp, corona grid and wire, etc., were full of toner. Unfortunately I'm not able to get a type 21 developer in acceptable time, so I can't change it right now, but as far as I have seen, it looks like there is not much developer inside the dev unit, disassembling the hopper I can see the inside of the dev unit. But still, the machine now is printing quite good. Values have come back to Vsp 3.80-4.20, vsg 0.30 - 0.60, but vt is quite low, 1-1.50v. Cleaning entrance seal (recovery blade) of the drum has 4 or 5 breaks, it's not in good conditions, as well as mylar seals in the cleaning blade bracket. Prints look quite good, copies too, the problem is that if I print more than 10-15 copies it comes out with some ghost images of the previous prints, approx. 1,5cm of distance (don't know if I'm clear). Let's say, in a grey background characters already printed below are now white impressed. I made a jam myself and drum would look quite clean, but i'm going to confirm it tomorrow. Looked inside the drum unit, quenching lamp is quite dirty once again, only on one side, as well as the top of the cleaning blade, dirty only on one side. There shouldn't be toner there, however. Another point does not convince me is the cleaning roller below the transfer belt. It has some toner melt along itself, I cleaned it with alcohol, not very thoroughly because I was not that sure, but still. Actually what I can say for sure is that the increasing value of Vsg, and consequently light copies, in my case, were caused by the plate that grounds together drum and developer unit, were you put a screw and the drum knob. Well, if it is not correctly inserted, even some millimeters, copies begin to fade inesorably. As soon as you push it towards the inside, first become immediately better. I hope I will be helpful, and I Hope you will be for me too. :P
P.s. This machine is in these condition because it has never had any PM.

the toner scattering around the lengthy path is the major factor and is manipulated by several motors /pumper as well as sensors. Nothing to be blamed for the design at early that time. Complicated mechanism of toner transportation into the development unit and faulty sensor reading triggered irregularly toner supply command. toner overflow caused scattering around, As matter of factor, Vt lower value means high TC, its higher value indicate low TC(Toner Concentration). However, don't believe too much about V(x value) (SC350 310 etc logged hundred times in the history within short period, still print out normal ) . Focused on the fussy values self-adjustment usually don't solve the problem completely, just a temporary measure, especially for developer changed . By looking at real print problem, dirty background, ghost or offset images, A lot of senior technicians always say: change parts this and that, like Drum, or Developer, cleaning blade etc. But it doesn't last long, similar symptom will re-appear. after certain volume like 100k or 200k which mean nothing for the Production machine. Usually minimum test pages 100+. Evaluation of print quality must be 1000 + as stable condition. Reality is that it is toner itself - inferior to magnetic properties less charge control additives in toner components. No one admits the secret. Well the problem will keep on appearing for aging machine( meter counter usually several millions above).

Clean Blade, even a new one, is not enough force to block the accumulated Residual Toner. Keeping the stable cleaning effect largely reply on the stability of the charge characteristics of Toner.

[Iowatech]

Make sure you are running enough prints. The larger Ricohs were made to be run, so if not enough prints are made the toner feed doesn't run long enough to keep up.
If you can find the toner feed time adjustment in service mode, you might try reducing that value. Sometimes that helps.

[crystalsound]

Some updates: I started today printing 100 pages in duplex, after 50 the copier returned SC495. Prints looked really excellent, only a bit dirty along the edge, really nothing in the paper. The second job stopped after 30, this was another problem signaled by the customer. Cylinder was really full - too much actually - so I unplugged the three hoses between cylinder, hopper and pump, and I found all of them clogged. Vacuumed everything and started other 50-80 pages, no errors at all, prints are perfect, still in duplex, still some dirty along the edge. The problem comes out when I print in one side only, after some pages copied I get some dirty background with white words within it. It looks like the blade or the brush - both of them are new - aren't able to clean the drum as they should, and it only happens when copies come out at 90ppm. I remind you that recovery blade (they call it seal) has some breaks, and one of the two mylars between the drum and the cleaning blade is not attached anymore. May I use hot glue for it? Could this problem be related to setting powder of the blade? I didn't have it and I used waste toner, but I can get it, if it is necessary.

1.jpg2.jpg3.jpg
Here is the problem. Forget about dirty on copies, it's my scanner. The only problem is at the last page, and it's ghosting as I said. You can find the word "presente" in the last page (8), that was printed int the first page (6) "presente in metamorfosi".)