GR3750 Pressure Roller Not Lowering

[The Future]

Hi,

I have a GR3750 that typically prints quite well, but will often do this annoying thing where the pressure roller will engage (press against the drum) on the final print through the machine. This causes a double impression on the drum (which transfers to the paper when a second run is started -- and which gradually fades after 30 or so prints), and can cause the drum to get lodged into the machine (which I have fixed by putting the 3750 into test mode and running the pressure roller operation test).

Any ideas? It's an annoying issue that leads to headaches and wasted paper and it would be good to eventually sort out.

Perhaps helpful: it seems to be a more persistent issue on certain drums, and less so on others.

Machine has over 1,000,000 impressions and 15,000 masters and is otherwise in pretty good working order.

Thanks!
Jeff

[jermyth]

Re: GR3750 Pressure Roller Not Lowering

Sounds like the pressure solenoid and/or the hook lever are out of alignment.

[RRodgers]

Re: GR3750 Pressure Roller Not Lowering

Sounds like the pressure solenoid and/or the hook lever are out of alignment.

yep that. I use to file the hook a little and do the adjustment.

[The Future]

Re: GR3750 Pressure Roller Not Lowering

yep that. I use to file the hook a little and do the adjustment.

Is that better or worse than adjusting the "length from the end of the Print pressure adjustment screw to the bottom face of the Print pressure adjustment gear."? Or does that adjust something different?

When you say file, do you mean file down the flat part on the hook that makes contact (the top), or some other part of the hook?

[jermyth]

Re: GR3750 Pressure Roller Not Lowering

This is a different adjustment. And I belive RRodgers was referring to the hook and catch getting burrs on them causing them to stay caught.