C224 blank pages

[mrfuser]

Ok client called and said blank pages being printed and copied and no error. On arrival found same. Replaced dv unit and drum, test prints for CMY out of service mode all good, K is still blank with no error recorded.
levels for toner show 6% across the board and voltages read vdc-k 407 and vg-k 525



any ideas?

k

[Synthohol]

how did it pass gradation adjustments with no black?

[larweedad]

I have one doing the same thing. New Dev., drum, hi voltage, drive assy, front board, cleaned print head. I did not have a print head to swap. I am curious what you find. My PH was a single beam, all my donors were not. Prints would start then go blank and stayed blank on black only, color was fine. Test page looked cool thou. Talked the costumer into buying a new copier and delivered it this morning.

[mrfuser]

not sure what you refer to. It will not do gradation. I did test prints for each color out of test print mode in service and cmy were fine but black is blank.

how did it pass gradation adjustments with no black?

[copyman]

If K drum, developer units have been replaced only thing left is HVPS & PH unit.

[tsbservice]

SD4

[mrfuser]

Sd4 as in the solenoid for the black dv unit or the drive for that?

[tsbservice]

Yesimage.png

[kingarthur]

What were the gears like on the DV unit you took out, quite often there's one gear that wears down, and the corresponding gear on the drive unit, also wears. Resulting in no drive to the DV unit, is the DV unit turning ?

[Toxic]

Agreed with TSB, SD4 often cause problem like this.

[KMFLT3CH]

Check the drive gear for K dev at the back of the machine. Is it stripped? Mark one of the teeth on K dev and see if it turns after one page.

How does the demo page/test page (with the bird) look? If colors are there but missing black lines and text then replace SD4.

This also affects 8 series machines.

[Tech09]

If I remember correctly, remove the K drum, dev and belt and from the right side slide your phone in and take a picture of the drive gear to see it better. If the K drive gear is worn and you have a loaner machine in your shop pull the drive from the loaner and use one of the color drive gears to swap out your bad K gear.

[tsbservice]

Lucky me I never had drive gear stripped to the point it wouldn't turn developer unit. Just out of interest I would expect some sort of grinding noise, am I mistaken?

[kingarthur]

Lucky me I never had drive gear stripped to the point it wouldn't turn developer unit. Just out of interest I would expect some sort of grinding noise, am I mistaken?

You'd think so, but no noise, at least according to the customer, there isn't. I've probably had about a dozen, believe it or not, it's actually one of my favourite jobs biggrin.png

[kingarthur]

If I remember correctly, remove the K drum, dev and belt and from the right side slide your phone in and take a picture of the drive gear to see it better. If the K drive gear is worn and you have a loaner machine in your shop pull the drive from the loaner and use one of the color drive gears to swap out your bad K gear.

I find the quickest way to diagnose it, take out the DV unit, run your finger along the mag roller, so there's a clear patch, refit the unit, if the patch is still there, the DV unit isn't turning....