AB Dick 9870 Novice

Hello all,

This is my first time posting on this forum. I am new to the printing industry. My mother was employed by the owner of a printing shop (one AB Dick 9870 offset printing press w/ T-head and two Canon Imagerunners). He recently passed away and left the business with my mother. I know nothing of printing (I'm a junior in college for engineering if it means anything), but I've received a crash course on how to operate the machinery. However, when I run large amounts of copies on the offset press, faint ink lines begin to appear horizontally along the page. The lines become more apparent as the machine spits out more copies. However, if I stop it from feeding and let it sit there running for a moment, then begin feeding again, the lines vanish and then gradually start reappearing again. No matter what I do this continues to happen! Am I doing something wrong, or do I have a bad blanket or something? Any light someone can shed on the situation would be marvelous. Thank you all very much.

 

Sounds like your plate is drying out. Have you tried increasing the dwell time of the ductor roller of the dampening unit (if you have the stock dampener)? Also, check your ink forms to plate stripes and make sure they look alright.

 

The dwell time of the ductor roller was (and continues to be) at maximum since I began operating the machine. I did add a few ounces of alcohol to my fountain solution and it seemed to take care of the majority of the problem. The gentleman who crash-coursed me told me my fountain mix should contain 4 ounces of fountain solution with the rest H2O. I was unaware alcohol was needed in the solution as well until today. Still one or two faint toner lines, but hardly visible. A vast improvement. From what I understand, the rubber fountain roller (forgive my lack of technical speak) is a bit too slippery and not gritty enough to pick up solution as well as it should. I suppose to completely fix my problem I should have this roller replaced? Thank you very much for your reply.

 

Is the roller "flared" on the ends really bad? If so, then yes, replace it. How much water are you using when you put 4 oz of water? Gallon? Quart? If you are putting 4oz in a quart, that seems like quite a bit.

 

Does your water system have a chrome water ductor roller and a rubber pan roller with fiberglass seals on each end? If so you should be using a mixture in a quart bottle of 8 ounces of 99% anhydrous alcohol fill with water almost, depending on the type of plates, add 3.5 -4 ozs of silvermaster or megamaster fountain solution or 1/2 oz to 1 ounce of universal fountain solution depending on if your using distilled water or hard tap water. These two rollers do not ink up, they stay clean. Water goes in the press first then ink up and set up feed, wash up then drain water. Running the press with no water will damage the roller from friction between the dry seal and the roller.

 

Yes, my water system consists of a chrome water ductor roller and a rubber pan roller with fiberglass seals on either end. So you're basically saying, for every quart of mixture, it needs to be 1/4 alcohol and 1/8 fountain solution (depending on type. I'm not sure, so I'll check). I am using hard tap water, and I believe the alcohol is 99% isopropyl. Does this matter? I'm not sure what the volume of the stock fountain reservoir is, but it seems as though I need to be much more careful and precise with my mixture. Thank you very much for your knowledge.

 

hi use alcohol 10% and Ph 5.4

 

Yes, this water system is designed to use 25% alcohol. In warm weather the bottle mixture can be increased to provide a workable solution in the pan. A Hygrometer is recommended to monitor percentage at point of operation. A hygrometer can be ordered at Kelly paper or most Graphic Arts supplier runs about $35.00. Depending on the type of plates and ink being used the percentage of alcohol can be adjusted between 6 to 10 ounces per quart. Below 4 ounces will result in toning issues. Too much fountain solution will retard the driers in the ink. What type of plates are you using? Fountain Solution?

 

Mr sethhensel .
Problem may be by wrong roller setting.

 

For plates, I'm using Silver Master Paper Plate SLM-RIII. As for the fountain solution, I'm using ABDick Proformance Fountain Concentrate.

Elaborate?

 

On another note, I tried the specific mixture of 1/4 alcohol with 1/8 fountain solution with the rest H2O in a quart of mixture. I noticed tone lines beginning to appear again, and I added alcohol directly into the fountain. This seemed to remedy the problem.

 

Do you know how to check and adjust the forms? Check out, under this forum, post # 20 and 34 under "ink problems with t head" for form adjusting directions.

 

Hey Guys... new here. I am operating an AB Dick 9870, I do have a little offset experience, but no pro by any means, I teach Graphics at a Vocational Program. I want to know sometimes my press will give me a double hit on the blanket (so prints a sheet, hits the blanket without a sheet, and them prints a sheet again) and sometimes my press just feeds through the stock "regularly" ... but I am not sure how I am getting it to do this. Can someone help me.?

 

Ink up your system remembering to have water solution in the pan to prevent roller and seal friction on the ends. Turn form rollers to the off position, (2) place control lever to the ink position, (3) mount plate tightly and rotate the press so the plate is under the forms, (4) rotate forms to on position then turn off. (5) This will leave a contact stripe on the plate. Upper form should be 1/8" (3.2 mm) to 5/32" (4 mm). Lower form should be 5/32 " (4 mm) to 3/16" (4.8 mm). If you need instruction on adjustments just ask.

 

Review my post by clicking on my name and review post to get details on roller adjustments