Description and user's instructions of JL-series lithographic presses of Polymetaal.
These presses are mechanically operated by means of a lever at the top pf the press. The pressure is transferred by a knee-joint mechanism to the scraper bar holder. The height of the scraper bar holder can be adjusted and secured. The work top is made of varnished, water resistant ply-wood.
The crank drives the roller via the gear wheels. The crank can be detached from the drive mechanism and in this way the work top can be pulled back manually after each print.
This action is slowed down by a spring buffer. The worktop is provided with a handle for this operation.
The gear-wheels are protected by a steel cover. A standard feature of the press is a paper shelf mounted on the top. There is however room for two paper shelves.
Underneath the worktop on the side of the press where the stone is inked are ball-bearings which run on two steel rails, mounted in the inside of the frame. The worktop, on the other side, rolls on nylon rollers.
The scraper bars can be supplied in any chosen length. Scraper bars made of wood, with a leather brace, can also be used with this press.
The tympan, which is placed between the paper and the scraper bar during printing, is also made of a synthetic material.
The lithographic stones can also be supplied.
Lithography presses JL-series, user instructions.
- First clean the roller. For safety reasons the roller is packed with grease paper and plastic tape. Make a very small cut in the plastic tape which allows you to peal off this material. The roller must be cleaned from grease with a solvent and must be clean and dry before use.
- Place the prepared lithographic on top of the bed. Because of the weight of a bigger stone, it is advisable to move the stone with a sort of trolley. Polymetaal has a "rolling table", the RT-60, and a "graining Sink", the LS-11, of which the height of both products (87cm / 34") is the same as the press. The equal height of these products facilitates the moving of the stone.
- Insert the correct scraper bar into the scraper bar holder. The tapered side must point downwards. The groove in the scraper bar holder is 2 cm wide, which enables the insertion of the 1.9 cm wide scraper bar. The scraper bar is made of a synthetic material, but acts the same way as the old scraper bars made of wood and covered with a leather strip. The scraper bar should always be a little shorter than the width of the stone. If it was longer, marks might become visible at the outher ends of the scraper bar, because of the edge of the stone. A small hole has been drilled in the scraper bar holder. This hole is used to keep the scraper bar in place. Copy the hole to the scraper bar, while it is in place. Make de hole in the scraper bar a few mm bigger and secure it in the scraper bar holder by inserting a nail into the hole. Check carefully that, under pressure, the nail can be moved in and out the hole without a problem. If so, it means that the scraper bars back is well placed against the craper bar holder.
- Adjust the height of the scraper bar. If the lever on top of the press is down, the scraper bar should transfer the right pressure to the stone. Before this is acomplished however, one should adjust the height of the scraper bar holder by turning the three spoked wheel. If one has found the right position, the wheel can be secured by tightening the M30 hexagon nut.
- Dampen the stone with a sponge and ik it with a roller, as normal.
- Put a sheet of paper and the tympan over the stone. The tympan is made of 1mm thick PVC. Put some grease on the scraper bar.
- Turn the handle which makes the stone move towards the scraper bar. Set pressure on the stone by lowering the lever. Check carefully that this is not done on top of the edge of the stone, since it might lead to damaging the stone ans scraper bar. The scraper bar should be lowered between the edge of the stone and the beginning of the image on the stone. The pressure that is required for printing depends upon many things; like moisture in the paper, ink quality and quantity, paper, etc., and is subject of experimentation.
- If the stone is under pressure, turn the handle, towards the other end of the stone. Never go until the edge of the stone, since it might lead once more to damage of the stone. Just stop again between the end of the image on the stone and the edge of the stone.
- Put the lever up again, which raises also the scraper bar. Remove the tympan, and the print, and continue this cycle for the next print.
The press will be used in a humid environment. This will cause the cylinder and the rails to rust. This is not a serious problem. It is perfectly allright if there is rust on the cylinder. Do not grease the cylinder, this might lead to slippage. The rails can be greased however, to avoid too much rust.
Keep the gearing also greased. Once a year is fine.