Hello –
I have a few questions about my Reprex No. 2. I was hoping some other Reprex owners might be able to share some operational insight. Thanks in advance!
In the Reprex PDF it is recommended to lubricate the following items:
- cam shaft, cams, and linkage in ink system lifting mechanism
- rider and form roller bearings
- ink distributor drum shaft
- either face of the knurled feeding knob and on the screws
I know where these parts are generally located (except knurled feeding knob), but need some help identifying the individual parts that the manual refers to. Also, when you oil a bearing where do you actually insert the oil?
I am also having a problem with the oscillating drum printing on the very end of the tympan (1-3 inches). It’s the edge of the tympan right before it wraps around the reel rod (opposite end of the grippers). It seems that the (ink lifting?) mechanism that houses the motor, oscillating drum, and automatic wash up area does not shift downward on the return stroke. The cylinder actually seems to bump the ink lifting mechanism (?) into the correct position hence printing on the tympan. Is this normal? It doesn’t seem right at all.
Let me know if you’d like to see pictures and I can upload a few. Many thanks!
Video:
Never saw a Reprex but am thinking about the variables. Form height should be constant, and roller height should be too. Cylinder should shift between trip and print heights. That leaves the drum height as a question.
Now think about the .918″ print plane, which would also have been bed bearer height when new. This should be constant for the form, but form trollers adjusted slightly below that, and the stock-and-packing combination variable for amount of impression, but below that plane or ink won’t transfer. Stripping packing from the cylinder until the drum doesn’t ink it would also remove the pressure needed to transfer ink from form to stock.
Back to the ink drum. You need enough contact between it and the form roller to drive the whole inking system. But that contact would bring the drum above the .918″ plane. So there must be a mechanism to deflect the cylinder from the drum as it passes over, or ink will transfer from drum to topsheet as it passes over. Some presses deflect the drum down with bumpers, some raise the cylinder to trip as it passes. What else can be done?
The only time I saw this specific problem it was with a 219 OS, which is a rare Vandercook model that allows adjustment of drum height. Even rational adjustment of the drum required packing to be shortened so that only the drawsheet was over the cylinder at the tail. That shop folded and I don’t know how this solution worked in the long run.
The ink drum on SP series Vandercooks is pushed down when the (horizontal) tie rod contacts an arm (raised plate on the outer end of the drum shaft. This allows the impression cylinder to clear the ink drum. There should be a similar action on your press.
The only other thing I can think of it that your impression cylinder is mis-timed (out of alignment), because the carriage was removed at some point. It’s not clear from your images. the gripper bar should be at 90 degrees when at the feed board.
The terminology can be a bit confusing. As I noted previously, bearings can be multi-part assemblies or simply holes or notches in a part to support a shaft.
To lubricate the form roller bearings, which in this case are notches, add a small amount of oil directly on the ends of the form roller cores (aka journals) so that it seeps down into the bearings (notches).
For the shafts, apply a small amount of oil where they make contact with another part.
The knurled feeding knob refers to the Pressure Ink Dispenser. These were useful when just a single color (black) was needed over a period of time to pull proofs of engravings or repros (sharp kiss impressions of type on camera-ready paper to make offset plates).
We have the same press at Foothill College in CA. Our tympam inks the same way but a much narrower strip. We cut the angled corners more so more bare cylinder is uncovered. Most of the time the form printing is much smaller so the tympam at the end isn’t needed so the undersheet do not go all the way to the end. Unless you are printing a full 15″ x 22″ paper, the image never goes to the very end of the impression cylinder.
I think the main bearing are sealed so can’t be oiled but they do need to be wiped clean along the the upper and lower rails.
We use one sheet red board, two .006 tympam and an .007 mylar. We found that .003 or .005 mylar was too thin. It is a student press and the thicker mylar withstood the small type impressions better.
Lastly, the movement of our ink cylinder is more or less the same as yours. Hope this is helpful.
I’ve attached a few pictures and videos. The video titled Mechanism Movement shows how freely the housing for the motor, oscillating drum, and automatic wash up area move. The picture titled Pivot Point shows the set screws that possibly tighten that housing apparatus. I’m not sure whether it is moving too much and resulting in the tympan printing. Or if the mechanism is moving as it should. The movie titled Tympan and Oscillating Drum show the point at which they meet. I hope you find these helpful.
Also, I’m pretty sure my packing is tight and appropriate for the paper I am printing on. The Reprex has a cylinder undercut at .040 and the manual recommends adding an additional .002. I am using three sheets of .006 tympan, .004 mylar, and two sheets of .0012 tissue.
Thanks for your help!
Photos are generally helpful. I’ll encourage other Reprex operators to comment. Meanwhile:
Your packing may be baggy or too much over cylinder.
Plain bearings (solid single cylinders with a simple bored hole) should be oiled regularily.
Typically, carriage bearings are multi-part assemblies that are sealed with ball bearings packed in grease and do not need further lubrication. You can wiped the narrow casing surface with a slightly oiled rag and occasionally wipe the sides, but make sure that oil or solvents do not seep below the surface.