GR3770-Paper wrapping around drum

[Jschaudt]

My current issue is that my paper is often wrapping around the drum. I fixed the machine enough that the initial print and all ones run slowly align properly. But, I get some that wrap around the drum. those ones do not align properly. I have checked the picker arm on my machine, and it is good. Good airflow too. I know that this one muct be caused by the cam for the timing roller. Any recommendations for proper adjustment? I threw mine out of whack. I know how to make it worse very well.

[joelsa12]

Well as you know the Riso is an ink on paper process, the ink that the Riso uses is a little tacky. If you are running heavy ink or a line really close on your lead edge then this problem will occur no matter what you do. With that being said. It seems from what you describe that your image is moving around as you print. I am going to assume that this is correct. So why is the image moving around? Things to check: Is the stripper angle set correct( green dial on the right that you can see on the side of the machine when you take your paper out), is the timing adjustment set properly( distance the arm connected to your timing roller is from the cam when it is at its low spot should be around 2.5 mm), or finally something in your timing and guide section is out of wack or broken. The cam that controls the opening and closing of the timing and guide rollers sometimes can be mistakenly changedwhen setting registration. You will know this is in the wrong place if you see the problem on 11X17 paper and not on 8.5X11. If there is a faint squeaking going on as the machine is running then your load springs are worn out causing your registration to bounce. These are the springs that are on the guide roller(metal roller on top in the 2nd paper feed section). Make sure that the rubber rollers on the bottom in your 2nd paper feed are cleaned with some rubber rejuvinator if they are slick and dirty. Finally your timing or guide roller is worn out and need to be changed. This is all I have on registation moving around at this time I hope this helps.

[joelsa12]

Proper adjust ment for the cam. Put the screws in the middle and start from there. There is no exact adjust ment for this that I have found to work on all machines.

[Jschaudt]

is the timing adjustment set properly( distance the arm connected to your timing roller is from the cam when it is at its low spot should be around 2.5 mm), or finally something in your timing and guide section is out of wack or broken.

So, I need a gap between the roller bearing on the tip of the arm and the Cam? I don't right now. I'll try and adjust that tonight.

[joelsa12]

At the high spot on the cam you will have no gap. You must make sure that the machine is rotated to where the bearing on the arm is at the low spot on the cam. If you look at the bank of boards on the left hand side if you are sitting behind the machine. Around the top of the board there is a free rotation button. Pushing this button with the machine on will cause the main motor to rotate. You will then be able to watch the cam, arm, and bearing and make sure that it is at the low spot when you check this adjustment. This is not the easiest adjust ment to perform. It is not just loosening set screws and moving it. You must make sure that the timing roller is engaged all the way to the guide roller before you do it. I would check it at the low spot if it is off I will find a way to talk to you and explain how to do it.

[Jschaudt]

My cam guide has been adjusted for best print positioning. My timing lever/arm was not set right. It was too close.

Now, when the cam guide is at the peak position, do I want the timing roller to peak: Same, Early or Later?

Paper is running through better. Less sheets end up backwards in the drum area. A few lose their registration. The roller is still grippy and has been rejuvinated.

[joelsa12]

My cam guide has been adjusted for best print positioning. My timing lever/arm was not set right. It was too close.

Now, when the cam guide is at the peak position, do I want the timing roller to peak: Same, Early or Later?

Paper is running through better. Less sheets end up backwards in the drum area. A few lose their registration. The roller is still grippy and has been rejuvinated.

Interesting way to say it. Here is that I do to adjust it. Put cam so the arm is at the low spot. between the bearing and the cam put a 4 mm allen wrench. the loosen the set screws on the on the arm with 2.5 mm allen. then take something and stick in the hole in the timing roller. I use a 2 mm allen wrench. twist the roller till it is all the way engaged. while keeping that tight tighten the 2.5mm screws on the the arm. once tight pull out all wrenches and the adjustment should be perfect.