The paper is not smooth sheet-fed offset press production process is the most common problem, and also one of the normal production of offset press start to solve before good questions. Lead to feed a common cause of failure is due to the paper separation mechanism and lose send mechanism according to the characteristics of the paper can't regulate the good. All kinds of machine of the operation instructions and all kinds of professional books on a large, detailed introduction, but they are usually used in the paper as the main object to introduce operation and adjust party method. The author previously service enterprise mainly produces packaging color box, usually board quantitative in 300 grams above, this kind of board than ordinary sheet-fed heavy a lot, if lose paper breaks down, not only affects the production efficiency, and may even for rubber cloth printing machine to bring a lot of damage. In this paper, according to the author printed cardboard experience to Heidelberg SORSZ sheet-fed offset press as the main basis, discuss offset printing cardboard in the feed control and trouble shooting some different ordinary paper printed comments, refers for the colleague, communication.
1. The paper separation mechanism of regulation
Overall, printing of cardboard paper feed control than printing paper easy. Because board massiness, blow loose paper and operating paper need more wind, so attention should be paid to regular inspection, cleaning pump filter and mouthpieces, suction nozzle, in order to ensure that there is enough air. Generally speaking, printed cardboard to the mouthpieces and suction nozzle air open to maximum, deliver paper suction nozzle and points paper suction nozzle of the rubber band to use big and thick, loose paper mouthpieces should choose cylindrical member, will wind together and can blow loose paper pile top 3 ~ 5 pieces of cardboard. The machine with standard in paper brush, suitable for ordinary paper printing, with standard metal points paper tablet for cardboard, we found or partial soft, and is easily broken, if long-term purchase will increase the cost of certain burden, we adopt method is the metal straps grinding out certain thickness as tablet use, the effect is very good. Due to their grinding tablet is harder, cardboard and hard than ordinary paper, so steel sheet can't into paper pile too much, generally not more than 3 mm, otherwise the board be sheet steel block, even the first piece of paper can be points paper suction nozzle suck up.
Due to the steel sheet of paper into less, so the requirement of paper more clean, if the cutting board length error is too big, can for tablet press too much, or no scrape and appear to feed fault. In addition, due to the board than a hard, it is not like thin paper be points paper suction nozzle suck up later, tow tip part paper edge is oblique sagging state, so pressure paper mouthpieces cannot into paper pile too much, otherwise you will trample suck up the first board. In short, thick board on the separation mechanism of requirement is: the air is enough, the tablet is hard and has good elasticity, paper cutting size accurately.
2. Double a control mechanism of regulation
Mechanical double a controller is through the control between two wheels of the paper thickness to detect double zhang, should say printed board are more likely to adjust double a controller, it is important to note that: board thickness accuracy are often not as good as tissue paper, paper cutting, paper cutting knife if a little blunt point, board at the back of the fiber in the cut edge not in order, so that caused by double a controller board thickness has certain error, adjust the height of the double a controller, the error will be taken into consideration.
3. Custom parts of regulation
Heidelberg printing machine using pull gauge wheel and pull paper bar component side pull gauge. Printed cardboard, in order to provide greater pull, pull gauge wheel pressure support spring need for coarse, pressure is bigger, cardboard in pull gauge wheel under the pressure of easy to cave in, plus board cutting to have rough edges, board surface and pull gauge plate if close contact due to friction and pull does not reach the designated position, as shown in figure one shows. So when printed cardboard must pay attention to the adjustable high pull gauge plate of high degree, with the board surface is between 0.2 ~ 0.3 mm gap.
Due to long-term printing machine cardboard, are used in coarse brace spring, overcome spring support force will pull gauge wheel drive up the force bigger, can lead to contact point A severe wear parts, as shown in figure 2 shows, after surface wear that pull gauge wheel carry enough high, when pull gauge wheel in high, also not enough to let two ZhangHou board from the below, the results by the board of the bite site has entered the pass paper roll, but tow tip position in pressure roller, will be blocked after pick another one board from la gauge wheel by lose forward gauge, cause board skew and stop. Our machine in printing thick and large board had met this ask questions, making feed cannot, remedial method is in wear and A recess in spot welding, let pull gauge wheel can carry higher some, to ensure that the pressure roller carried from the pull paper after iron can make two pieces of cardboard pass.
Most modern printing machine adopt pendulum former gauge, to boot usually have 6 ~ 8 only ago gauge. Board is water absorption material, because the moisture content change and deformation, the paper Angle may tilt, if the board bite side and side pull gauge edge at the intersection of the corner just in close to the one before the inside of the gauge, as shown in figure 3 shows dotted line place, so when the board on delivery can be successfully before the arrival of the gauge. But when the side gauge pull board, normal location position should be former gauge pressure under the tongue, but become warped up paper Angle may be fallen before gauge pressure within the tongue blocking side and pull does not reach the designated position, or will board and oblique off. This fault although not easy to happen, but once appear, can lead to positioning is not allowed. We take the measures are: in the printing before they pay attention to some specific size of the board, if the board width is equal to about two symmetrical former gauge inside distance, need to pay special attention to, if necessary and permits, as far as possible move side gauge positioning position, make board to avoid the awkward position, is avoided, and the paper Angle exists tilt phenomenon, there is the risk of pull does not reach the designated position, can only temporarily before gauge uninstalled, to print out this batch of products, put back.Because of the uneven moisture content and undulate curved board in the top gauge place, because a hard board, paper feed table suction and will not absorb flat cardboard, cardboard bite edge easy to former gauge pressure in front of the tongue blocking, and could not enter the former provisions, therefore may need to use a tough pressure slip pin arch or tilted board bite edge, as shown in figure 4 shows. If pressure slip from former gauge is near by, when the ability of bite edge one-handed paper roller bite drawing-in machine, this before gauge has fallen from the position of the set up, and in the highest position, then the ability of tow tip part, was the top of the gauge and pressure slips out below, due to the back of the board are usually rough, the gauge pressure on the tongue surface is a long-term friction, head become some sharp, before the gauge pressure tongue may put the board back blow break, as shown in figure 5 shows. Scraping broken paper randomly range are attached to the back of the cardboard into the machine, will pressure the bad press rubber cloth, the tablet can't be too hard, also can't press too hard. If there is need to use hard tablet, also cannot pressure in front of the former gauge or too close to the place, should be placed in the first gauge side, separated by at least 1 cm. Of course, the ideal situation is board in kaifeng cutting, and immediately into printing, flat board will not need to use steel tablet press, nature also won't appear this problem.
4. Pass paper mechanism of regulation
Recursion offset paper tooth row of teeth cushion height can be adjusted, for the average commonly used paper, teeth cushion height according to the factory set of can, but if printed cardboard, it is necessary to adjust to teeth cushion height, or falling teeth cushion and feed table between the spacing is too small, may encounter board, not before the arrival of the gauge. The height of the teeth cushion set up to consider the paper thickness and former gauge pressure tongue height, if former gauge pressure tongue low and teeth cushion is high, will appear before gauge pressure tongue control the height of the paper, and grind make paper raise phenomenon, the paper bite edge appear wave deformation, causing overprinting is not allowed. If strictly according to the thickness of the paper before the adjustment gauge and teeth cushion height, thickness for printing the frequent change of the board is too much trouble, so our teeth cushion height only do two Settings: one kind is 300 grams of the paper, the former gauge according to the paper thickness adjustment, respectively, to dental pad machine on the reference set; Another kind is 300 grams above board, considering the board's bite edge thicker, won't because of collision and bending, the height of the gauge before up to the highest, teeth cushion is transferred to the highest position.
5. The paper mechanism guide board regulation
Because board thicker, equivalent diameter roller and the paper cylinder SORS series for offset printing machine, paper be forced to pass along the arc process will produce greater resilience, therefore, SORS series offset printing machine transfer paper roller has three used to protect paper along the roller rotation direction orderly progress guide note, as shown in figure 6 shows, generally speaking we hope three guide note in the board width within the position. If the board is small, also can use one or two, but avoid by all means does not just its placement on the edge of the board, that may be because the printing process, the deformation of the board or bar of small mobile, appear board side is iron scraping, guide to the edge of the board by scraping the rotten or from the teeth to fall off, stir rotten in the machine, cause rubber cloth damage, serious word, even damage the machine. In the same way, the paper the roller spread many used to prevent paper back smearing of small wheels, this small wheels and do not just on the edge of the board, or may also appear board edge blown rotten or board off the disease.
6. The paper device regulation
Because board is very hard, no matter whether printing full version of the field, do not need to open the flat paper suction device, otherwise, not a flat paper effect, it will suction powder injection. Reduction wheel absorption volume generally the largest open, and shall always clean up the reduction rounds of suction hole and filter, in case of lack of air. However, due to the board quality big inertia, along the direction of rotation to drum length short board, or because not enough reduction action time, need to carefully according to the board thickness, size, printing speed regulating factors such as tooth row of teeth in the teeth of time.
When printing paper is generally accept paper parts of the bedding paper cleat tight, make the printing paper in as far as possible. But printed cardboard, the paper on the symmetry principle paper machine of the distance between the size of the paper should be better than older. Otherwise when Richard paper machine to bunch in moving, because the board is hard, both ends under pressure, easy to downward arch, as shown in figure 7 shows, for a printed sheet of the ink layer a bigger force, leading to the back smearing.
The above, we use Heidelberg offset printing SORSZ double-color board, is different from the ordinary paper printing, the need to pay more attention to place, and we have taken some measures. Although we have used the machine prescribed maximum printing thickness is 0.8 mm, but in the production we often printing thickness more than 0.8 mm to 1.2 mm, even the board, in pay attention to the details of the above aspects, the paper did not appear in other problems.