RA Drum: Master shorter than drum area

[joaodoria]

hello,

I have recently acquired two used RA drums (and have been using them on a RA5900) and when comparing it with my original black drum, I see that those two drums don't get to have the master wrapped around all of its extension. (photo attached)

I have a service manual but don't know where to look for it. I saw a similar discussion on the topic "GR3750 printing short images"

[Iowatech]

Re: RA Drum: Master shorter than drum area

That drum was designed to be used with shorter paper only. I can tell that is the case because the ink doesn't go to the trailing edge of the master.
Some drums were made that way to accommodate people who worked primarily with the shorter paper. That way they didn't waste master material.

[joaodoria]

Re: RA Drum: Master shorter than drum area

That drum was designed to be used with shorter paper only. I can tell that is the case because the ink doesn't go to the trailing edge of the master.
Some drums were made that way to accommodate people who worked primarily with the shorter paper. That way they didn't waste master material.

[Iowatech]

Re: RA Drum: Master shorter than drum area

I'm pretty sure there are two things you will need to convert that drum: the metal drum shell from a drum that was designed for printing on longer paper (if you look closely at your drum from the picture, you will notice that there are no holes in its shell to let ink through to accommodate printing on longer paper), and the circuit board from a drum that was designed to print on the longer paper (that is what tells the machine what size of master to produce, and whether the drum is used for color or black ink).
If you do choose to try to convert the drum, I would recommend that you put drop cloths on anything that you don't want ink on, as Riso ink can be somewhat unpredictable when it is outside of its expected environment.

[joaodoria]

Re: RA Drum: Master shorter than drum area

I'm pretty sure there are two things you will need to convert that drum: the metal drum shell from a drum that was designed for printing on longer paper (if you look closely at your drum from the picture, you will notice that there are no holes in its shell to let ink through to accommodate printing on longer paper), and the circuit board from a drum that was designed to print on the longer paper (that is what tells the machine what size of master to produce, and whether the drum is used for color or black ink).
If you do choose to try to convert the drum, I would recommend that you put drop cloths on anything that you don't want ink on, as Riso ink can be somewhat unpredictable when it is outside of its expected environment.

Right (sounds like a nightmare! ), a next question would be about how do I make sure that the PCB I get is actually fit for this conversion?

Two notes:

1) When I bought the drum I was getting an error message (don't remember the exact code but it had to do with the drum size) which I solved by changing the dip switch (thanks copytechnet!). I couldn't find the exact meaning of each RA drum dip switch (couldn't find it on the RA/GR tech manual; is there a separate manual for drums?); is there any chance that a certain dip switch setup would affect the drum behavior? I know you already mentioned that the problem has to do with the drum build, but the idea just crossed my mind.

2) I understood the only difference between RA and GR drums is the actual PCB. Is that really it? I wonder if I could actually buy a GR drum (a lot easier to find than the RA ones) and switch the PCB. Crazy idea.

Lemme know your thoughts on this and thanks for the exchange.

[DAG COPIERS & COMPUTERS]

Re: RA Drum: Master shorter than drum area

The RA drums are quite different from the GR drums. While the former is designed to print for A4 and B4 size paper, the latter accommodate prints of up to A3 size. True the RA &GR machines share most features and functionality, and even the service manual. If you look carefully through the manual, especially towards the end pages, you will find a section devoted exclusively to PCB and the DIP switches and their configuration. This should resolve your dilemma. You don't need to buy GR drums for use in RA machines, it would be a waste of resources including time.

[joaodoria]

Re: RA Drum: Master shorter than drum area

Thanks, I found the dip switch info on the appendix section and will look again when at the studio.

I put mine to work by copying the settings on my working B4 black drum so it seems like I can't go much further than what @Iowatech had suggested previously. Let's see.

[joaodoria]

Re: RA Drum: Master shorter than drum area

@Iowatech :

In your previous answer, when you said "meant to work with shorter paper", do you mean that was an A4 drum instead of a B4 one?

Or some kind of B4 variation? Because after opening the drums for cleaning the master started to wrap a further up but the ink still doesn't go there (and according to your comment it won't).

I recently found the sides of the drums have an "A4 II" inscription on them.

I also recently found that the drums are getting ink blotches on the master area edge (see image).

And checking my dip switches they're actually set to B4 (I copied the switches from my working black drum (B4 for sure) but maybe the two drums I bought used were in fact A4). I only learned later in time what each dip switch means by looking at the service manual.

Could it be that I'm the one provoking the blotches by changing the dip switches, or would you say by looking at the image that the nylon screen ripped?

(or something else?) – sorry, many questions.

but thanks in advance!

IMG_1759.jpg

[Iowatech]

Re: RA Drum: Master shorter than drum area

@Iowatech :

In your previous answer, when you said "meant to work with shorter paper", do you mean that was an A4 drum instead of a B4 one?

Or some kind of B4 variation? Because after opening the drums for cleaning the master started to wrap a further up but the ink still doesn't go there (and according to your comment it won't).

I recently found the sides of the drums have an "A4 II" inscription on them.

I also recently found that the drums are getting ink blotches on the master area edge (see image).

And checking my dip switches they're actually set to B4 (I copied the switches from my working black drum (B4 for sure) but maybe the two drums I bought used were in fact A4). I only learned later in time what each dip switch means by looking at the service manual.

Could it be that I'm the one provoking the blotches by changing the dip switches, or would you say by looking at the image that the nylon screen ripped?

(or something else?) – sorry, many questions.

but thanks in advance!

[ATTACH=CONFIG]29488[/ATTACH]

The drum in the picture you shared (Thanks!) is one that was designed for shorter paper. It appears that the dip switches were adjusted to make the machine make a longer master.
To find out for yourself if that is the case, carefully remove the drum screen and look for where the holes in the metal drum shell that allow ink to reach the master end.
If the drum shell has the designation "A4" stamped into it, that is the largest paper that it was designed to print on.
Actually, it is kind of important to pay attention to that designation, as it applies to more parts on Riso GRs that you might think.
Well, I hope there's something useful for you here. If not, sorry about that.

[joaodoria]

Re: RA Drum: Master shorter than drum area

A bump on this:

Does anyone know if RA5900 have different models for A4 or B4 sizes? I tried to reset the dip switches for my A4 drums to its initial settings (so it prints A4). When inserting the drum in, I get a E61 error code which is "Drum Unit is wrong type or size".

Could it be that the B4 machine can only take B4 drums and not A4 ones? I don't get to find any other explanation.

Alternatively, is there anything I can do on the system board to override this and make the machine to work on A4 only, then?

Thanks a lot,

[joaodoria]

Re: RA Drum: Master shorter than drum area

The drum in the picture you shared (Thanks!) is one that was designed for shorter paper. It appears that the dip switches were adjusted to make the machine make a longer master.
To find out for yourself if that is the case, carefully remove the drum screen and look for where the holes in the metal drum shell that allow ink to reach the master end.
If the drum shell has the designation "A4" stamped into it, that is the largest paper that it was designed to print on.
Actually, it is kind of important to pay attention to that designation, as it applies to more parts on Riso GRs that you might think.
Well, I hope there's something useful for you here. If not, sorry about that.

Another info: seems like what makes the ink leak on the drum edges is a pair of misaligned ink blocking plates.