How to pack press for a good impression
Dear Briar Press subscribers,
Meaghan from Australia here. I have a heidelberg t platen. Can anyone help me with some tips on which side of the press to pack for a good impression. When do you stop? how much it too much? Balancing between the impression lever and Tympan packing in the platen and packing the bed of the press.
Also should you change it for every job? in the middle of a job depending on how much you are printing?
Please can you help me??
Use as little and as hard a packing as possible - your type lasts longer.
Look on the reverse of the paper, you don’t want to see the type impression read through to the back.
You want to “kiss” just enough.
The impression lever knurled knob is generally adjusted when a heavier form/larger type area is being printed. We generally found it un-necessary to adjust much on a day to day basis
Avoid adjusting impression by adding paper or tissue to the back/bed of the form.
(not that every pressman hasn’t done so)
Make you adjustments under the tympan.
To make the intitial adjustment to the platen we would lock 60-72pt bold cap Ws, in the 4 corners of the chase. On the platen a red pressboard or 2, then a couple of card index, then a couple of 20lb. then tympan.
Adjust the knurled collar on the inpression lever so the Ws print evenly top and bottom. You will need wrenches for side to side impression issues.
BRILLIANT! thanks heaps and heaps!!
Now I just need to find where the side to side impression adjustments are??
I am very new at this and my terminology is a bit off - sorry I am getting better - but thank you so much for your help - this is really great stuff…
I’m not sure if there is a left to right adjustment on that machine. Hopefully you won’t need it. C&Ps have 4 bolts w/ lock nuts at the platen corners for adjustment.
RE tympan use/re-use.
No need change tympan during a run unless print quality deteriorates - generally good for 2-5m if packing reasonably firm.
No need to change after every run. Print on as many areas as makes sense - business cards here, envelopes there etc.
Let print quality be your guide.
Dick,
Actually I know it has been a while but could you tell me what card index is? I thought it might be a thing us aussies are not familiar with??
I am still tracking down the right supplies so I can get printing - it hasn’t been easy!!
thank you,
Meaghan
I was referring to cover/card stock uncoated in the 65 to 90lb range. The stuff index cards are made of. We indiscriminately called them, cover, card, index.
Here is a link to International Paper’s site. Look at the left side bar for good info. Since most printing today is offset lithography their focus is in that direction.
http://www.internationalpaper.com/Paper/Paper%20Customer%20Segments/Prin...
A great place to start with the proper packing is to keep it hard in surface. There is a built-in caliper (go/no go) on one of the uprights of the heidelberg platen press which allows you to gauge your packing for the proper thickness (should be approximately 1mm or 1/25”. Of course, you can alter your packing to suit particular work you plan to do.
I use pressboard and a few thin polyester films then the standard spotting sheet and tympan. I find the tympan lasts for quite a good period of time if you are using a hard packing. I often run 20 - 30,000 envelopes without a worry in the packing. I do a careful makeready before running which keeps my typeform and packing in good condition.
John Henry