Thermal Print Head - Streaking

[pj4nh]

I have been getting some streaking on my RZ 310. It started as a single line, then two, then five. I attempted to clean it with dry x-70 wipealls; I later tried cleaning with alcohol - it helped briefly. It became a concern so I located another print head. The peculiar part of this is when I first acquired the machine there were no issues with print quality. The machine has very low counts: 270K Impressions 5100 Masters.

Once I acquired another print head I got a wider spectrum of streaking but in a different location.

I have examined Masters from my original print head that had been burned using test code 80 checkered pattern and see the streaks in the master itself.

Based on those results I have deduced that the print heads have been damaged or are "dying" - which is again strange for such low usage.

Below are pictures of prints from both print heads and an image of the master from my initial print head (I shipped the purchase print head back to see if it was my machine that was causing the errors - pressure rollers, mirrors, etc).

IMG_0688.jpgIMG_0684.jpgIMG_0687.jpgIMG_0685.jpgIMG_0476.jpgIMG_0474.jpgIMG_0501.jpgIMG_0497.jpgIMG_0493.jpgimage1.JPG

Any insight would be appreciate,

PJ

[Iowatech]

Re: Thermal Print Head - Streaking

This might be a long shot, but have you tried resetting the machine using the "Reset" key (holding it down for ten - fifteen seconds while turning the machine on)?
I have seen where a voltage fluctuation caused the thermal head's output to become even worse than your pictures show (although that was on an older Riso line). The reset cured that problem.
Also, are you using master material from Riso? Sorry, I've seen buildup on the thermal head from non-OEM masters cause something similar to this. That would explain why cleaning the thermal head only helped temporarily.
Actually, you might want to try a different master roll out of an unopened box even if you are using OEM masters.
Sorry if this is a waste of time.

[pj4nh]

Re: Thermal Print Head - Streaking

This might be a long shot, but have you tried resetting the machine using the "Reset" key (holding it down for ten - fifteen seconds while turning the machine on)?
I have seen where a voltage fluctuation caused the thermal head's output to become even worse than your pictures show (although that was on an older Riso line). The reset cured that problem.
Also, are you using master material from Riso? Sorry, I've seen buildup on the thermal head from non-OEM masters cause something similar to this. That would explain why cleaning the thermal head only helped temporarily.
Actually, you might want to try a different master roll out of an unopened box even if you are using OEM masters.
Sorry if this is a waste of time.

No worries - I've been using OEM Masters since I've gotten the machine. However I do believe that the prior owners were using non-OEM masters and inks - hence why i've lost a lot of the original purchases - drums, master disposal belts, pressure rollers, etc. you name it - i've pretty much replaced it.

I'll swap out rolls tonight and report back.

Also - I've tried resetting the machine but when I power it on while holding the reset button - nothing really happens to let me know if the machines been reset. Is that normally the case? I figured I'd get a beep//flash//robot-response of some sort.

Thanks for the response.

PJ

[imihm]

Re: Thermal Print Head - Streaking

No worries - I've been using OEM Masters since I've gotten the machine. However I do believe that the prior owners were using non-OEM masters and inks - hence why i've lost a lot of the original purchases - drums, master disposal belts, pressure rollers, etc. you name it - i've pretty much replaced it.

I'll swap out rolls tonight and report back.

Also - I've tried resetting the machine but when I power it on while holding the reset button - nothing really happens to let me know if the machines been reset. Is that normally the case? I figured I'd get a beep//flash//robot-response of some sort.

Thanks for the response.

PJ

Hi hello there

I wonder whether you are adjusting the thermal head power when replacing new one ...please try that.

Thanks

[pj4nh]

Re: Thermal Print Head - Streaking

Hi hello there

I wonder whether you are adjusting the thermal head power when replacing new one ...please try that.

Thanks

Hello All,

Thanks again for the insight

I replaced three separate master rolls - all the same result.

Adjusted the TPH power in increments of 5 within a total span of 200 [100 south and 100 north of the TPH voltage listed on the TPH]

Still no difference.

I don't know what else it might be other than the TPH - but two dying on me - both with low counts... sounds awfully unlikely the TPH is dead.

I guess I just don't understand the mysticism of RISO

[Elle]

Re: Thermal Print Head - Streaking

have you tried cleaning the write roller? you might try swapping that out if cleaning doesn't do anything.

[pj4nh]

Re: Thermal Print Head - Streaking

have you tried cleaning the write roller? you might try swapping that out if cleaning doesn't do anything.

I haven't tried that but I have two unique streakings from two different TPH's

If it were the write-roller, wouldn't the streaking occur in the same place?

If it weren't the TPH that was the issue - would something else cause streaking in two different locations but the same on each print head after deinstalling and reinstalling (changing the power each time as well).

PJ

[Elle]

Re: Thermal Print Head - Streaking

there is a sticky grit that will sometimes build up on these rollers that will resemble little black pills in the tray beneath the roller. when you are working with TPH you will often move this grit around on the roller itself causing the streaks to move about somewhat. from your images it looks like they are running in the same general area (if I am interpreting the images correctly) but if the change was more than an inch from TPH to TPH then its likely not the roller.

I will say that in 6 years of servicing the RZ series the only time I replaced a TPH it turned out to be a faint groove on the write roller and my senior tech informed me that he had never replaced one. that's not to say they don't go bad but we never had one. I did replace a lot of write rollers over the years however.

at any rate cleaning the write roller is cheaper and easier than replacing the TPH, the same applies to swapping it out if you have access to another roller.

good luck with it.

[pj4nh]

Re: Thermal Print Head - Streaking

there is a sticky grit that will sometimes build up on these rollers that will resemble little black pills in the tray beneath the roller. when you are working with TPH you will often move this grit around on the roller itself causing the streaks to move about somewhat. from your images it looks like they are running in the same general area (if I am interpreting the images correctly) but if the change was more than an inch from TPH to TPH then its likely not the roller.

I will say that in 6 years of servicing the RZ series the only time I replaced a TPH it turned out to be a faint groove on the write roller and my senior tech informed me that he had never replaced one. that's not to say they don't go bad but we never had one. I did replace a lot of write rollers over the years however.

at any rate cleaning the write roller is cheaper and easier than replacing the TPH, the same applies to swapping it out if you have access to another roller.

good luck with it.

Thank you - Don't mean to be dismissive but there's something wrong with the machine that is being overlooked. I cleaned the write roller last night and no success.

Only 250K Impressions and 5500 Masters - I get the same streaking on each TPH but why would I have gotten the initial streaking from my original TPH? Doesn't seem like the machine was in use long enough to get streaking but I'm not sure. It started as two streaks and has grown to five, all further than .5" away from the original two streaks.

I have a brand new TPH coming in early next week. If that doesn't work - I don't know what will!

Appreciate all your advice,

PJ

[20gaugeO/U]

Re: Thermal Print Head - Streaking

You bought a 2nd TPH (used?) and got lines in a different spot. Buy a new TPH and your problem will be fixed. Sometimes the elements just burn out, no reason or volume coralation. Make sure when you put the new one in you change the TPH resistance in the protected test mode.

[pj4nh]

Re: Thermal Print Head - Streaking

You bought a 2nd TPH (used?) and got lines in a different spot. Buy a new TPH and your problem will be fixed. Sometimes the elements just burn out, no reason or volume coralation. Make sure when you put the new one in you change the TPH resistance in the protected test mode.

got a new TPH and streaking is gone - however i do get a faded right edge now on most of my drums but especially black. I'm thinking it might be the pressure roller.

It also might be the squeegee inside the black drum.

thanks again

[Iowatech]

Re: Thermal Print Head - Streaking

got a new TPH and streaking is gone - however i do get a faded right edge now on most of my drums but especially black. I'm thinking it might be the pressure roller.

It also might be the squeegee inside the black drum.

thanks again

If the light area is the same for all of the drums you have, you're probably on the right track with the pressure roller.
However, on the off chance the machine has just been idle for too long, you might want to engage the "idling" function when you make a master and see if that helps first.

[pj4nh]

Re: Thermal Print Head - Streaking

If the light area is the same for all of the drums you have, you're probably on the right track with the pressure roller.
However, on the off chance the machine has just been idle for too long, you might want to engage the "idling" function when you make a master and see if that helps first.

The fading has increased significantly which caused me to become overzealous and attempt to readjust the pressure roller.

I got back behind the boards and was testing out the rollers positioning when I realized the roller had become stuck after it dropped down when I loosened the two black bolts that hold it up.

Now when I try to set it back - it locks up and won't freely move back under the solenoid lever.

I had it moving back and tried to run some prints through the machine but either the roller wouldn't pick up the paper or it would have a jam error and not make an impression.

Attached are some images - any ideas on what I may have seriously fudged up?

IMG_3723.JPGIMG_3724.JPGIMG_3722.JPG

[20gaugeO/U]

Re: Thermal Print Head - Streaking

Sounds like your machine is out of time or your pressure adjustment is not right. I hope you own the book, look in the adjustments of the press section for details. It wouldn't hurt to the have the Jig's they mention also (the right size wooden dowel rods work too).

Easiest thing to do would have been try a new pressure roller. They are pricey but since the machine is 10 years old the original one is probably swollen with ink and paper dust buildup. Thus not inking/pressing the edge.
I haven't worked on a 310 but I'm going to assume it has the Density arrows on the control panel (like a 390). If it does it would have been better to adjust the pressure with the motor in service mode, after replacing the pressure roller. Hind sight 20/20.

[pj4nh]

Re: Thermal Print Head - Streaking

Sounds like your machine is out of time or your pressure adjustment is not right. I hope you own the book, look in the adjustments of the press section for details. It wouldn't hurt to the have the Jig's they mention also (the right size wooden dowel rods work too).

Easiest thing to do would have been try a new pressure roller. They are pricey but since the machine is 10 years old the original one is probably swollen with ink and paper dust buildup. Thus not inking/pressing the edge.
I haven't worked on a 310 but I'm going to assume it has the Density arrows on the control panel (like a 390). If it does it would have been better to adjust the pressure with the motor in service mode, after replacing the pressure roller. Hind sight 20/20.

It sure is - I replaced the pressure roller prior to that adjustment. I should have looked for an alternative TM adjustment before going behind the boards to physically adjust it.


I have a tech coming in next week to look at it. I just can't figure out why the roller is stuck to the bottom of the machine.