uneven inking! help!

I have a c&p 10x15 old style that is having some inking issues. I will attach a pic and would certainly appreciate any ideas!

image: photo.jpg

photo.jpg

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Tell us more about your press; do you tape on the rails?

See threads about taping rails on a C&P.

Check to see that your rails are flat in the area that the inking is problematic, especially on the side that is closest to “from six oclock” portion of the plate.

How many rollers are you printing with? All three?

What is the condition of your trucks? Anything noticeable on them that is protruding? (not as likely, or it’d have to be in the same spot on all three; which is possible if they have gained flatspots from being rested on the inking disc for a prolonged period.)

List of possible problem areas:
Trucks not round
Rubber on rollers not round/straight
**Something on rails/uneven rails with a bump (most likely)
Could be uneveness in plate, but unlikely? I assume you’re using polymer..

Process of elimination:
Firstly, run an impression through, note the place where the uneven inking is. Next, with everything in more or less the same position, rotate ONE of your rollers 1/4 of a turn- leave the other two how they are.
Pull an impression.
Repeat, checking all three rollers for a flat spot or problem on the trucks.

However, I suspect it’s on your rails- as the inking on that spot is consistently thin.
check your trucks for foreign stuff stuck on them (would only be noticeable once every time they turn).

Good luck!

Thank you so much! Yes I am printing with all three rollers. I have taped the trucks and the rails. I will check them and see if there are any problems with them. I will use the checklist you gave. Thanks so much!

Hmm. I think taping the trucks could make some bumps on them if not done effectively. Certainly it’d be difficult to make them flat.

However, I feel like there may be something on your rails. That’s my sneaking suspicion.

Good luck.

Thanks again, I have taken the tape off the rails and am adjusting the tape on the trucks and it seems to be working. I had to take a break to run some errands, but will get back to it. Is there a trick to knowing how much tape should be on the trucks or is it just trial and error? Sure appreciate your help!

I run a Heidelberg, whats the purpose of taping your trucks?
I would think over time it would wear and gum up things.

to all

When the morning daily newspaper where I worked went to photosetting (cold type) I devised a test/calibration for density of exposure, which is a little like uneven inking.

I sent a test to the photoset machine. Two 24 point discs of black, about 50% over-lapping. Adjust exposure control knob to just make the overlapping part the same “blackness” as where there is no overlap.

Has anyone tried devising a test, a forme of discs, intended to be solid black, each disc about 12 point diameter. Separated (white) about 12 points. Run once through press, Then do the same again with the same sheet, but with paper displaced about 6 points sideways; can you visualise result if the inking is OK, and visualise result if inking is not OK?

Sorry that my description is limping, hope a few can decipher/interpret my meaning.

Alan.

P.S. I like puzzles, I have just suggested a way of substituting for the way turn indicators (trafficators) on English Morris car,circa 1950, work; I had not realised their simplicity/complexity till my electrical engineer (associate diploma) son raised the problem this weekend.

Alan.

P.P.S. Has the Briar anything to do with the Tar Baby, apart from getting ink (blackness) on your shirt?

Alan.

to all

In the paragraph “Has anyone tried devising a test …” throw in the word “letterpress” somewhere; makes some sense (perhaps) then.

Alan.

Theo, the windmill has adjustible rails so no need to tape the trucks, most presses do not so either you tape the rails or the trucks. i still have the trucks to my 8x12 c&p with about 1/8” of electrical tape on them, the tape has to be replaced after about a year or so if you use it a lot. I never was a big fan of taping the rails, mostly i taped the trucks. On my c&p i use the morgan adjustalbe trucks, you can still get the replacement rubbers for them from NA Graphics,

Melissa:

If you are adjusting the rollers to give you even inking, you need to set them to some standard. A tool that is great for this is the roller setting gauge available from many sources. It consists of a “lollipop-shaped device which has a milled diameter of .918” (US). You slip the gauge under the roller and pull it back to see what diameter of stripe it shows, adjusting each roller end so that it gives you the correct stripe on the gauge.

If you don’t have one of those, you can use a mounted plate, and mount one roller at a time on the press, inked. Roll the roller over the plate and adjust the height of the roller (in your case by wrapping the roller trucks with tape) until it adequately inks the form.

In reality, if you have good rollers and trucks, it is better to put the tape on the rails as you will only have to adjust it for one roller and the rest will fall in line. There must have been a bump either on the rail or in your tape application which caused all three rollers to jump at the same spot. If this was in your rail, you will still have that problem, if it was in the tape application, you should be able to remedy that.

I have wrapped roller trucks in order to get trucks of varying diameter to work well with the rollers they are on, but as a rule, if all the rollers and trucks are the same diameter, taping the rails is a better option and much easier to get everything in adjustment.

John H.

Hi Melissa- unless your trucks are a different diameter than your rollers, and your rollers are LARGER than your trucks, you should not need to tape your trucks.

Think about it: No matter what, there will always be a ‘lap mark’ hop- where the tape ends and has to graduate in size up over itself- and so you’ll get a ‘high spot’.

So, I think taping the RAILS ONLY is your solution. Many have their own methods, and many methods have been suggested on this site- each speaks to the experience of the printer making the suggestion.

I prefer to use 3/4” wide nylon strapping tape over one layer of electrical tape (the electrical tape is on the bottom in case I need to “re-start”.) I find this tape doesn’t stretch so I like it. Get the kind where the strapping runs the LENGTH of the tape, and there are no pieces criscrossing.

I place a boxcar base with small pieces of polymer (usually crosshairs actually) in all four of the corners, 1/2 way along the sides as well, and one row also in the center of the base.
I run strapping tape in strips along the length of the rails very carefully- I turn the press over by hand and slowly pass the rollers over the ‘test form’ until I get just the right inking in all four corners. Then as long as my base lays flat in my chase, I’m OK to have it ink up well as I go and I just remove all my test pieces and mount a plate. I’ve found this method to work well for me.

Be sure to “stagger” your tape at the top, as this will help the rollers ride up onto it without ‘hopping’. This advice is in numerous places, including the NA Graphics website (where they sell some nice plastic tape for this purpose) and on a lot of the threads about this on here as well.

Dick I know.. Just seems something is wrong when you have to use tape. The only thing you have problems with the windmill, if too much oil gets on the rails or the trucks, it makes it for sloppy and slur printing.

Melissa,
Clearly you have a problem with the ink roller either jumping up or not contacting the plate in a specific area. Or the ink roller is sliding across the form in that particular place.
Presumably judging by the photo you are feeding the long side of the card into the press so that the long side is parallel to your rollers.
One of the questions I’d ask is-does the blank area move down the card on subsequent impressions. Does the blank area ever get to the ampersand and then to the “Mr.”?
If so this progression would indicate that the rollers are sliding at some point rather than rolling. In which case it is very likely due to the key being loose in the main gear. This would cause this slippage on a regular progression until the point which it comes back to the top of the card and works its way down. I have a similar press and ran into this problem a few years back.
The jumping issue may be the roller carriers not re-seating due to friction or lack of oil.
If you want to talk you can call me at 917-509-4844.
Good luck
Steve

Just my two cents, I have a 10x15 as well. I use painters tape.. ( the green kind ). It is amazing how much of a difference one strip of tape can make. I usually have 3-4 on mine.

What Steve mentioned above about the roller carriers - I had the same problem - turned out to be gunk in the spring it was not pulling the arm back in and it was indeed sliding.

Paul

Looks to me as an impression problem. If you have three rollers you should be getting ink on the image.

Linotype metal would give you this type of problem, might also be a bad poly plate problem. Low spot on the poly or poor packing on press.

This is not an inking problem.

Aaron,
Au contrair. If you can rotate either the form or the chase and the missing area remains in the same place it is probably in the plate. If it remains in the same place relative to the bed of the press it may be packing. If the gap moves in progression as stated above it is in the ink train and possibly in the gear.
Scientific method. One piece at a time!
s

Just had a similar problem, although a much thinner area that wasn’t inking. Followed Paul’s advice about “gunk in the spring” which helped tremendously. Cleaned the spring and the channel the spring is in with a toothbrush (not the same one I use every morning!) and hit the springs with some 2-in-1 oil. The “sliding” that causes the form to not ink can be imperceptible by watching the rollers, and the cleaning/oiling can only help!

Have you run a job earlier and kept your old underpacking in the makeready beneath the tympan ???
While we often keep a tatty tympan on the platen for a few jobs we do change the underpacking for every job !
Polymer plates will show the slightest bruise in old packing as a glaring blank as you have on the printed stock
If the impression is present although the ink is not then the problem is with your inking as mentioned above ,hopping being my vote . A wrinkle in the tape or a doubled over bit , as you mention carrying three rollers and its constantly in one spot then the rollers must be all passing over the same high spot .
Sorry the trucks in your language not rollers ,the rollers are being raised by the high spot???