Riso RP - Master Mis-Feed problem in one color drum

[mapere]

Hi,

Making a master on my red drum results in an error message "Master disposal problem. Pull out print-drum and discard master."
At the same time the new master sits in the master making unit curled up or folded accordeon-wise.

After removing the old master from the drum and cut off the new master from the master roll the whole process repeats itself when trying to make a new master. Even when there is no old master on the drum.

The problem occurs only to this drum, the other drums are fine and the load and other rollers in the master making unit seem tight.


Where can I check to solve this problem?

I don't know if this has anything to do with it, but:
- the problem started when i made a master from a file retrieved from the storage memory. Before, working from the glass plate worked out fine.
- the flange drive gear of the drum is skew. The drum has to be unlocked and slightly rotated counterclockwise to be installed. Though other color drums have the same problem and they work fine.
- it's a RP 3790


Any help would be appreciated.

M

[jermyth]

Re: Riso RP - Master Mis-Feed problem in one color drum

Sounds like one of the white clamp plate collars is broken.
Good luck.

[mapere]

Re: Riso RP - Master Mis-Feed problem in one color drum

Thanks for your reply.

Those little white rings don't seem to be broken, still rotate freely and keep the clamp plate at its place.
Physically the clamp plate looks fine, just like the clamp plates from the other drums.

Could it be the communication between printer and drum, a bad contact or something?

[Iowatech]

Re: Riso RP - Master Mis-Feed problem in one color drum

Could it be the communication between printer and drum, a bad contact or something?

Unlikely, the circuitry in the drum is mostly for the ink supply and drum type.

From your description, I would guess that you need to rotate the drum clockwise to install it, which would put the clamp plate directly in front of the area where the masters come out of the master making unit. That would cause the new master to accordion jam or curl over. But I could be wrong.

I think that drum is out of time, but I'm not sure. If you could share a picture of the entire back of the drum when it is locked, that would be helpful. Maybe one that includes the white plastic ring gear on the back of the drum as well as the tall screw on the clamp, too.

[mapere]

Re: Riso RP - Master Mis-Feed problem in one color drum

Thanks for your answer.

I will post a picture in the morning.

Standing in front of the machine the drum needs to be turned counterclockwise.
Locked, the drum is at a (less than) 07:05 position, but I unlock it and turn it just a fraction to the left to get it in the connecter inside the back of the machine at a straight vertical position of 06:00 o'clock.

I have checked the manual about a drum out of time topic, but couldn't find anything yet.

[mapere]

Re: Riso RP - Master Mis-Feed problem in one color drum

two pictures:

The detailed picture shows the dots of the plastic and metal gears aligning together. You can see the axis of the flange drive gear slightly out of its 6 o'clock position.

In the other picture the back of the drum with the clamp being locked. In locked position the drum can be turned a few mm, because the clamp is a bit loose. The screw of the clamp is tight though, impossible to screw tighter without damage.

Would you need other pictures?

[Iowatech]

Re: Riso RP - Master Mis-Feed problem in one color drum

I'm glad you have a manual (sorry for the run around, and thanks for the pictures). Take a look at section 9, pages 16 and 17 in the manual (drum body removal), that will help. Especially the precautions on reassembly on page 9-17.
If you can get things lined up as the manual says there, I think that drum should fit into the machine properly and the master shouldn't jam anymore. Be careful though, you will encounter sharp edges and ink during that procedure.

[mapere]

Re: Riso RP - Master Mis-Feed problem in one color drum

It seems that the problem is solved.
I removed the screen and drum body and did a good cleaning.

The clamp that locks the drum in 0 position was a bit loose, so I added a washer there.
The drum is steadier now and the flange gear drive gets closer to its normal angle, at least it fits in the printer in locked-drum position as it should.

The first test prints worked out fine.

Thanks again Iowatech for your advice!

M