Retrofitting a press to use a continuous ink feed?

[blazini]

It seems like you can upgrade an old webpress to use alot of newer systems (spraybars, remote ink keys, plate loaders, etc.), but I haven't heard of getting rid of ink ductors and using a "micrometric" or "film" metering roller. Or has it been done?

Seems like it wouldn't be too hard to engineer, just needs to be the right size, needs brackets to mount and pneumatics to throw it on and off to the ink ball and gets driven by the first transfer roller.

I run a Harris with remote keys and other operators are always manually jamming keys shut and messing up the fountain calibration. I'm using dividers to keep ink off the ends of the rollers with no image. I never saw anything like that on a press with a metering roller. Since the metering roller never touches the ball, a properly closed key (slight ink film) puts NO ink into the rack.

 

[Cornishpastythighs]

Metering roller systems still need calibrating(zero setting) so your operators would still be able to 'mess' around with it but there is less chance of them grinding the ink keys into the fountain ball. We ran a .004" gap between our metering roller and ink ball, The metering roller was screened(anilox) to hold ink better. I would think the engineering and cost involved to convert your press would be quite high unless you find a company that has done a few already. Maybe better and cheaper to get your press guys together and show them the correct way to zero set the ink fountains and then lay down the law.

 

[Deleted member 16349]

It seems like you can upgrade an old webpress to use alot of newer systems (spraybars, remote ink keys, plate loaders, etc.), but I haven't heard of getting rid of ink ductors and using a "micrometric" or "film" metering roller. Or has it been done?

.

I believe that continuous inkers of that type tend to have more density variation than ductor roller systems. They are quite sensitive to changes in water setting.

The company I used to work for actually converted some of their presses, which had continuous ink feeds to ones with ductors. Not sure if that was a good idea. Seemed more like trading one set of problems for another set of problems.

 

[blazini]

Metering roller systems still need calibrating(zero setting) so your operators would still be able to 'mess' around with it but there is less chance of them grinding the ink keys into the fountain ball. We ran a .004" gap between our metering roller and ink ball, The metering roller was screened(anilox) to hold ink better. I would think the engineering and cost involved to convert your press would be quite high unless you find a company that has done a few already. Maybe better and cheaper to get your press guys together and show them the correct way to zero set the ink fountains and then lay down the law.

I can go in, calibrate a fountain, and 2 days later I'll try to start a job...........servo errors all over, servos at 100% still not even letting a drop of ink out of the fountain. Everyone there knows what a zero setting on a fountain looks like, it's just that with a ductor, you'll never completely stop ink from entering the rack and building up on light coverage jobs. With a metering roller, the temptation was never there for anybody to turn the fountain blade into an inkball lathe.

I believe that continuous inkers of that type tend to have more density variation than ductor roller systems. They are quite sensitive to changes in water setting.

The company I used to work for actually converted some of their presses, which had continuous ink feeds to ones with ductors. Not sure if that was a good idea. Seemed more like trading one set of problems for another set of problems.

I noticed exactly what your saying on a Goss Urbanite newspaper press. Seemed like the lower you ran the water the more the color was all over the place. I just wrote it off as a cold-set ink thing but it may have had something to do with the ink feed. The company I work for now has 5 presses with ductors and 1 Man Roland with a continuous ink feed. The MAN Roland doesn't have this issue at all. The size of the Goss' metering roller was about 3" while the MR is about the size of the ink ball, which probably has more to do with it.

 

[Deleted member 16349]

I noticed exactly what your saying on a Goss Urbanite newspaper press. Seemed like the lower you ran the water the more the color was all over the place. I just wrote it off as a cold-set ink thing but it may have had something to do with the ink feed. The company I work for now has 5 presses with ductors and 1 Man Roland with a continuous ink feed. The MAN Roland doesn't have this issue at all. The size of the Goss' metering roller was about 3" while the MR is about the size of the ink ball, which probably has more to do with it.

Blazini,

I am not keen on either system, but that is another story.

With the continuous ink feed metering roller concept, I think problems are also related to the ink being used. We were running EB inks, which are similar to UV inks and they maybe more of a problem.

As an anecdote, we tried to run a metallic ink. We were running product for the food industry so the ink chemistry had to be special. Metallic inks were particularly difficult to make to meet food related requirements.

Anyhow, this test ink was put into the ink fountain and we started to run the press. The operators could not get this metallic ink to transfer over to the metering roller no matter how much the ink keys were opened. We even tried to go into the computer and reset the range of the ink keys to be twice as much but still it was very difficult to get the ink to transfer. The ink just came to the gap (0.004" - 0.006") between the ink fountain roller and the metering roller and was extruded right through that gap and then just about all the ink went back to the ink fountain. At speed, the metallic ink would not wet the surface of the metering roller.

Of course that test ink was not workable but after being shocked by such a problem in ink transfer, I started to understand that problems in transfer could happen for a lot of reasons. I can see that some inks might be no problem at all and others might show a problem.

 

[Greg Imhoff]

I agree with Erik on this topic also known as rheology Rheology - Wikipedia, the free encyclopedia This means the flow of matter varies so, solutions considered may or may not work, depending. My advice first is to check all roller settings next confrim check ink stripes then assure ink keys settings are accurately set and returnable to (0) memory set points.

For those interested we provide at Essex Products Group | Integrated Color Control Systems fit to any press new or in the field systems that simply work and known to be "bullet proof." For example KeyColor ink key settings return to zero on command from the console and, are also uniquely able to calibrate by hand even with no power at the unit. Rare but it happens so we provide.

So if operators are messing with ink key settings or, if you need more ink key control look to EPG to be in control. To reset to correct ink key zero points and to improve upon press rheology, simply means to print better. Get a GRIP go green on waste.

Sincerely,
Greg Imhoff
President GRIPdigital, inc. & Director EPG Color Solutions
(800) 394 - 7130 begin_of_the_skype_highlighting**************(800) 394 - 7130******end_of_the_skype_highlighting - office
(708) 557 - 2021 - cell
Skype: gregimhoff
Print Properties Committee Member and GRACoL G7 Expert
Essex Products Group | Integrated Color Control Systems

Blazini,

I am not keen on either system, but that is another story.

With the continuous ink feed metering roller concept, I think problems are also related to the ink being used. We were running EB inks, which are similar to UV inks and they maybe more of a problem.

As an anecdote, we tried to run a metallic ink. We were running product for the food industry so the ink chemistry had to be special. Metallic inks were particularly difficult to make to meet food related requirements.

Anyhow, this test ink was put into the ink fountain and we started to run the press. The operators could not get this metallic ink to transfer over to the metering roller no matter how much the ink keys were opened. We even tried to go into the computer and reset the range of the ink keys to be twice as much but still it was very difficult to get the ink to transfer. The ink just came to the gap (0.004" - 0.006") between the ink fountain roller and the metering roller and was extruded right through that gap and then just about all the ink went back to the ink fountain. At speed, the metallic ink would not wet the surface of the metering roller.

Of course that test ink was not workable but after being shocked by such a problem in ink transfer, I started to understand that problems in transfer could happen for a lot of reasons. I can see that some inks might be no problem at all and others might show a problem.

 

[blazini]

I'm not all that keen on fluid dynamics but it seems like a moot point in this case. I can see what Erik is saying, but that's not an issue I've seen with the heatset inks we run. Thinnest Ink I've seen run there is probably 872 or 871 gold, other than gloss varnish, which we run on a dialy basis. This ink has no trouble transferring through the continuous ink feed on the MAN Roland.

Also, there is no issue with keys not returning to "zero" on the ductor fed presses. The problem is that "zero" is never zero with an ink ductor. Our rollers are also generally set well. On a short run sheet fed press this may not be any issue. I'm sure this must be pretty common issue with any ductor fed press that sees 100k+ impressions per job with light coverage.

I get by most of the time, by doing things like turning to water off on offset paper and running the racks out on the fly. or cutting the fountain with dividers. I try not to add to the problem by closing keys past the proper "zero" point.