Toshiba 4555C crashes black developer

[acrewofone]

Out of the blue one day a customer of mine, with a 4555C Copier that had run fine for 3 years, said his copies had light areas, streaky and banded (it looks like what in their 6550C Bulletins Toshiba called "Developer Banding or Feathered Developer"). (the Mag Brush on the Deleloper Roller has light and dark areas). I replaced the Black Developer Unit with a brand new one, but it only lasted for a couple hundred copies, then crashed again, I replaced the Developer Unit again with another brand new one, again about a couple hundred copies and crashed. It copies and prints fine, no codes or anything, just goes "banded after awhile". I did notice that when I was running 05-2404 to set the new Black Developer, the middle number looks off (setting Black Developer 05-2404 on a different machines shows midele number k = 126, machine in question shows middle number k = 71. It has been so long since working on Toshiba 4555C/5055C, I can not remember what eash number stands for and the service manual does not say. I would think that of something is not making contact in the back of the Develoepr Unit, it would show up right away or code out. I uploaded a pic of the Developer Mag Brush.

On a good machine 05-2404 setup the numbers are:
K 1.61V
K 126
K 1.61V

On the bad machine 05-2404 setup the numbers are:
K 1.57V
K 71
K 1.59V


feathered developer.jpg

[blackcat4866]

Are you seeing any CE50 errors in the error log?

That center value "C" is sensor output control value, a reading from the temperature/humidity sensor ... maybe disconnected or failed? It's located in the front inner cover, towards the right in the fan housing.

I think I'd look there first. =^..^=

[MarkG52]

How does your K drum look? Is it scored through the coating where the little white spacers ride?

[Pirate1936]

Out of the blue one day a customer of mine, with a 4555C Copier that had run fine for 3 years, said his copies had light areas, streaky and banded (it looks like what in their 6550C Bulletins Toshiba called "Developer Banding or Feathered Developer"). (the Mag Brush on the Deleloper Roller has light and dark areas). I replaced the Black Developer Unit with a brand new one, but it only lasted for a couple hundred copies, then crashed again, I replaced the Developer Unit again with another brand new one, again about a couple hundred copies and crashed. It copies and prints fine, no codes or anything, just goes "banded after awhile". I did notice that when I was running 05-2404 to set the new Black Developer, the middle number looks off (setting Black Developer 05-2404 on a different machines shows midele number k = 126, machine in question shows middle number k = 71. It has been so long since working on Toshiba 4555C/5055C, I can not remember what eash number stands for and the service manual does not say. I would think that of something is not making contact in the back of the Develoepr Unit, it would show up right away or code out. I uploaded a pic of the Developer Mag Brush.

On a good machine 05-2404 setup the numbers are:
K 1.61V
K 126
K 1.61V

On the bad machine 05-2404 setup the numbers are:
K 1.57V
K 71
K 1.59V


feathered developer.jpg

I agree with Mark , we have had this regularly when the drums get down to metal , they strip the developer exactly like your picture

[acrewofone]

The rear end of the K drum was worn down to the base metal, so I installed a completely new drum/cleaning unit I happened to have. I will let you know how it goes, thanks guys.

[stooey187]

make sure you replace the end block if its grey colour one, known issue for poor contact.

Also, yep that drum wouldnt of helped.

Also again, had issues with blanking LEDs failing, will cause dev to get pulled out, usually ive seen this with grainy bands on prints near the failed LED.

[acrewofone]

So far so good....