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Yep, thats what i've been doing. You need to find the balance betweeen duct opening and spin speed. Sometimes the jobs are so tricky even one notch on the duct opening is too much and the difference needs to be made on the speed, its far easier to run solids than low jobs!

Thanks all, i think i have it sussed now. As the press is 90% computerised, even the ink adjustment from a scanned sheet to feedback to the ink ducts, it does have a limitation in that the computer does not compensate for very low coverage jobs, it will always over adjust. I have found a good...

I'm sorry but i have to mention this, as you say you are a novice and we all started somewhere, but has anyone showed you how to hold cloths / rags when cleaning down?? It sounds like you may have had a narrow escape with having your hand drawn into the rollers??? As to the problem, From...

Thanks all, point tested, the light coverage jobs look good but dark ones do not as the black does not trap onto the other colours. Interesting test but fruitless in the end. Thanks again Dave

Hi all, What difference does colour sequence make to a job? I know it does make a difference as a print engineer proved it with a hard-to-match purple when he swapped the Cyan and Magenta around and it worked much better. We are still printing K – M – C – Y as he left it but what would Y – M...

Hi all, What difference does colour sequence make to a job? I know it does make a difference as a print engineer proved it with a hard-to-match purple when he swapped the Cyan and Magenta around and it worked much better. We are still printing K – M – C – Y as he left it but what would Y – M...

Hi Meddington, i do always start off with a new curve then enter the data into edit-uncalibrated. I can also do the first fine adjustment that way but it gets really tricky when the values have been fine tuned and you just want say another half percent but spread out over maybe 20-60% range...

We have a Harlequin Rip, and it is doing odd things with the export data from our press-sign software, here's the scenario... Create a linear tone curve, set 60% at the 50% point on any curve, extrapolate the rest of the curve and save. Edit the curve from calibrated and enter 45% at the 50%...

Most of our jobs fall in the 5-15% coverage range, it was less noticeable on a heavy job. The TVI would go up and down throught the job, quite randomly. I will know more today after i fully test the engineers work. Dave

Hi all, getting technical now! Anyways, th eblanket wash is an impregnated cloth roll so no variation as such. The roller temps are around 25c which is nicely in the CTT of the ink. The variation seems to be continuous i.e. during the run. I am hoping to explain more as soon as i get my...

Thanks all. I am now testing the press following a day with its guts all over the place :) It looks promising, if it maintains the results i am getting so far, i will let you all know what the cause of my headache was. Dave

Now we're getting somewhere, thanks. It is a waterless DI press, so no plate or fount chemistry to worry about. The time lag is between jobs so anything from 30 mins to a couple of hours, no wash-ups as its all in the same day. I have measured a wedge of 20 consecutive sheets within a job too...

We're sheetfed. When i said 24hrs, thats an absolute minimum, usually 2-3 days. Dave

Hi all paper is stored in the press-room for a minimum of 24 hours before use, there is no fount solution, this is waterless printing, presume that the paper all came from the same pallet. I am not looking for a cause or area to look in yet , i am merely trying to ascertain what a normal TVI...

I can get rid of more variables... Its in an air conditioned room so temp never varies, 22 degrees C 24/7, Only one operator - me, single day shift, same hours each day, mon-fri, jobs are very similar as its a catalogue and all pages are similar, any more?? Dave

I was told to look for a stack core temp of around 30-35C

Hi all, Considering the following.... Same paper, same press speed, same ink set, same plate manuf, same blankets what sort of variation in TVI would you expect to see from job to job on a press? I am guessing at it being very low <1-2% ??? Dave

Hi all, On all of our previous machines the ink vibrator roller contacted the duct roller once for every sheet on a fixed cycle, nice and simple and has work for countless years. We now have a Presstek 52DI which has the default option of intermittant ink vibrator control based on a set of...

Ok, thanks all. Dave

Hi all, i once had a figure for the optimum stack temperature when running with IR but have lost it, anyone know what sort of temperature we should be aiming for on the stack probe? I know it dangerous if too much heat is put into the stack and have even had tales of stacks spontaneously...