Riso RP3700, code G256-paper jam near exit

[Philh]

RP3700 was running fine and paper jam G256 code came up. As there was no obvious jam I turned it off and on a couple of times and it resumed printing but only foe a few copies. Same code displayed, and again no jammed paper anywhere. Reset it again and jam code is still there. Icon on panel indicates jam is near paper exit.
I have come across this question a few times but never seen the answer. In the past I have had this code for no apparent reason and it has always resolved by either hitting the ok button or pulling the print cylinder out and pushing it back again, and then hitting the ok button.Anyone have any ideas?

[Iowatech]

Re: Riso RP3700, code G256-paper jam near exit

RP3700 was running fine and paper jam G256 code came up. As there was no obvious jam I turned it off and on a couple of times and it resumed printing but only foe a few copies. Same code displayed, and again no jammed paper anywhere. Reset it again and jam code is still there. Icon on panel indicates jam is near paper exit.
I have come across this question a few times but never seen the answer. In the past I have had this code for no apparent reason and it has always resolved by either hitting the ok button or pulling the print cylinder out and pushing it back again, and then hitting the ok button.Anyone have any ideas?

Is there any chance you could show us a picture of what the machine is printing when that error occurs?

If not, here's my best guess: what is being printed by the machine has too much ink coverage and a temporary drum wrap is occurring. The print will stick to the drum then for exactly one revolution and then be deposited in the receiving tray, leaving no visual evidence of a jam in the machine. If that does turn out to be the case, try reducing the image being printed so that the blank part of the print that comes out of the machine first is larger (maybe a quarter to a half an inch, or five to thirteen millimeters of blank space). That usually will take care of that sort of problem.

[Tonersniffer]

Re: Riso RP3700, code G256-paper jam near exit

I guessing you need to clean the sensor in the exit transport bed. see attachment.

Hope this helps

Tonersniffer

[Philh]

Re: Riso RP3700, code G256-paper jam near exit

I have found the cause - At the delivery (receiving) end of the machine there are two black transfer sensor belts about 1/2" wide which are spring loaded onto a small shaft with guide pulleys. One of these had slipped sideways and was not seated properly on the pulley, so the 2 belts were not in parallel with each other. Maybe the belt was put out of alignment with a manilla 6x9 envelope which had been running at the time?
Anyway, once I positioned that belt correctly the code instantly disappeared and everything ran fine again. I still do not understand how it sensed a jam as the belts were still transporting despite there being nothing to actually transport at that stage?

Anyway, thanks for the suggestions which were very valid. Must admit I did not think about the excess ink possibility causing sticking for 1 revolution. This is a great forum and I have learned a lot from it just by reading the posts on copiers and digital duplicators.

[Iowatech]

Re: Riso RP3700, code G256-paper jam near exit

I have found the cause - At the delivery (receiving) end of the machine there are two black transfer sensor belts about 1/2" wide which are spring loaded onto a small shaft with guide pulleys. One of these had slipped sideways and was not seated properly on the pulley, so the 2 belts were not in parallel with each other. Maybe the belt was put out of alignment with a manilla 6x9 envelope which had been running at the time?
Anyway, once I positioned that belt correctly the code instantly disappeared and everything ran fine again. I still do not understand how it sensed a jam as the belts were still transporting despite there being nothing to actually transport at that stage?

Anyway, thanks for the suggestions which were very valid. Must admit I did not think about the excess ink possibility causing sticking for 1 revolution. This is a great forum and I have learned a lot from it just by reading the posts on copiers and digital duplicators.

Thanks for letting us know the fix!

The timers that tell the machine whether a print has exited the machine or it jammed are pretty strict, so I'd guess the problem belt was slowing the prints down and that was what triggered the jam condition.

If the belt was the only thing that was out of alignment, it very well could have been the envelopes. On some envelopes, the outside corners are folded down and can catch in the vents as they come out of the machine. That can cause the envelope to get under the belt and pop it off the pulley.