MPC-7500

[Masterchief]

Re: MPC-7500

300k black, 1.91 million colour. Guess what sort of environment this piece of shit got sold into!

Obviously a colourful environment ha, They must have a great price on colour copies id say its some where to do with landscaping or along that road

Masterchief

[seeb]

Re: MPC-7500

I have had intermittent blurry copies caused by a faulty black drum on this model.

[zames77]

Re: MPC-7500

Could be the ends of the drum coming away from the cylinder at an angle, causing the drum to push away against the seals. Any drum motor lock SC's (can't think off the top of my head what it is) in the history?

[BLADE]

Re: MPC-7500

Could be the ends of the drum coming away from the cylinder at an angle, causing the drum to push away against the seals. Any drum motor lock SC's (can't think off the top of my head what it is) in the history?

left field lol

[zames77]

Re: MPC-7500

Left-field? I get this at least 3 times a day, lol.

[BLADE]

Re: MPC-7500

Left-field? I get this at least 3 times a day, lol.

fair dinkum, I,ve only got a handfull of these models and havnt seen that

[zames77]

Re: MPC-7500

fair dinkum, I,ve only got a handfull of these models and havnt seen that

It's not that common, actually hardly happens at all, but funnily enough I had one today where the end was starting to come away, you can normally just pop it back in. But worst case scenario, the plastic starts to strip off and builds up on the seals, pushing against the drum causing CQ issues until it jams up hard and stops the drum rotating completely.

[zulufan1]

Re: MPC-7500

I have begun to run into this more recently as well. At least 4 times now in the last several weeks, and it does appear to be caused ozone buildup on the black PCU. In each case so far, replacement of the PCU, and primary corona, plus cleaning all the filters seems to have resolved the problem, at least for know.

I actually had this on one one the coast today, and am waiting for parts......It is strange that it is occurring more this summer than in the recent past...

[ricoh]

Re: MPC-7500

it does appear to be caused ozone buildup on the black PCU.

Bingo, I think you are on the right track. Ozone contamination is usually the cause of this issue, and as the K unit is the only one that has a charge corona, it will usually always be the problem one.

[BLADE]

Re: MPC-7500

This thread is quite remarkable and unlocks some of the issues with this model. I,ve seen the condition on the sample also after having the pcu out for a few minutes during a call. Wasnt sure what was going on but the copies came good after about 200 copies.

I think that indicates the drums are over sensitive to light.

Are there any old Canon techs here from the NP4835 analog series? Those machines were released with a drum that 'went off' when exposed to outside light (faded patches). But more importantly they suffered 'light fatigue' during normal use from the exposure lamp and that model had a new invention which was a laser to do the lead edge blanking. The drums fell way short of their target. A few months later new drums were issued and the machines ran good.

I reckon the same thing is happenning with this model. The process control aint happy and amps everything up trying to get solids up, so you end up with overtoning, all because of a weak drum. 2 cents worth.

this post was b/s (except for the canon bit)(and the 200 copy bit)