Akiyama Press Testing

[joe pasky]

One of my printing clients asked me to print a test form on a used, rebuild press he was buying. The rebuild shop did a good job of setting up to run the test. We had pretty good, representative sheets, IMHO.

Everything looked pretty good until we measured 50 consecutive sheets. We had fairly big density and gain variations sheet-to-sheet....in cycles of three. I'm guessing that this has something to do with the triple impression cylinder design of this 'non-bearer' press. My question would be: is this behavior inherent in the design? (all the units displayed the same tendency) Or is something worn out? Would softer, compressible top and underblankets help?

Not my area of expertise...any help would be sincerely appreciated.

whatsthistellingme.jpg

[GazKL440]

Akiyamas tend to flog out cam-followers on the impression cylinders without VERY strict maintenance schedules. Often it will manifest as slight doubling of image-especially on lighter stocks.

Get them to run some heavier gloss stock (150gsm+) then try lighter and lighter stocks. If you've got a cam-follower on its way out gain and doubling will increase as the stock gets lighter.

You may be able to feel some slop in the bearing by unloading it and wiggling it a little: if it moves, it's toast. If it's really bad you'll be able to tell by eye: it will be discoloured and not roll smoothly around the cam.

Bear in mind that each group of 3 impression cylinders services 2 plate cylinders so 1 blown cam-follower will show up in 2 print units. If EVERY unit is showing the exact same issue it's a possibility that it's had a decent smash at some point and may have damaged something more serious.

Hope this helps a little

[joe pasky]

Sincerely appreciate the insight...

jjp