Advantages and Disadvantages of Cross Feed and Vertical Feed Offset Presses

Cross feed and vertical feed are two ways for the small offset press to feed paper. For large-size offset presses with more than four specifications, all models at home and abroad are cross-feeding, and there is no distinction between cross-feeding and vertical-feeding. why? If the vertical paper structure is adopted, on the one hand, the three large rollers must be thickened and the processing is difficult, resulting in unbalanced center of gravity of the equipment and affecting the performance of the machine; on the other hand, the length of paper feeding is too long, and pleating, tensile deformation, and tail swinging are likely to occur. Such phenomena. Due to the weakness of the cross-feed offset press in terms of rigidity, processing, longevity, stability, and speed, it also takes into account the small size of the 8-open format small offset press, the simple processing of the three large rollers, and the small length of the eight-feed format. Stretch deformation, tail swing phenomenon is slight, does not affect the quality of printed products, the ink layout space and other characteristics, so there has been a vertical offset small offset press. For several decades, vertical offset small offset presses have become the main force in the small offset press market due to its advantages of reasonable structure, rapid and flexible, easy operation, good stability, long service life, etc., and have been recognized by customers.
In recent years, with the rapid development of the fast-printing market, not only large printing plants have been printing equipment on the market, but also various small and medium-sized and individual printing plants have been printing equipment on the market. The market for small-format offset printing machines has seen a rare prosperity. The demand is increasing. However, due to the influence of the traditional structure of large offset presses, some printing customers in the society hold the view that cross-feed offset presses are better than vertical offset presses. In fact, this view is very one-sided. From the characteristics of the machine structure and user characteristics, cross-feeding and vertical-feeding papers have their own advantages and disadvantages.
For a small offset press of the same size, the offset mill has the following advantages compared to a small offset press that feeds the paper horizontally.
First, the structural rigidity of the vertical feed paper is stronger than that of the horizontal feed paper. Cross-feed offset presses are much wider than cross-feed offset presses. For example, the axis on the offset press, according to the principle of torque, the length is increased, its rigidity is greatly reduced, so the small offset press which crosses the paper is relatively speaking, the offset press without vertical feed paper has a long service life (pure commercial heavy duty Except offset printing machine).
Second, the manufacturing cost of vertical feed paper is lower than that of horizontal feed paper. In terms of the long axis of the offset printing press, the length is doubled. From the mechanical processing industry, the processing cost will surely exceed more than two times. From the current small offset presses on the market, those low-grade and low-price offsets are not included. Paper offset presses, small offset presses of the same quality and performance, are generally 20% to 100% higher in crossfeed than vertical offset presses, and are more expensive to use.
Thirdly, the quality of the vertical feed paper is better than that of the horizontal feed paper (except for the pure commercial heavy offset press), which is mainly manifested in the following two aspects;
Printing pressure, due to the horizontal offset roller, the length of the rubber roller is much longer than that of the vertical offset press. The rigidity issue brings with it pressure is not enough. Therefore, the effect of vertical feed printing when performing full-scale printing in the field is better than Cross-feeding paper works well.
Ink balance, due to the increase in the length of the water roller and the ink roller of the cross-fed offset press, the effect of quick ink distribution and the ink balance time are not as good as those of the vertical feed paper. Therefore, the actual printing effect is relatively small compared to the vertical offset paper offset press. Relatively poor.
Fourth, the vertical paper feeding effect is better than the horizontal paper feeding effect. Due to the influence of domestic paper quality, when the paper is fed horizontally, if the paper is bent due to the excessively long edges, the effect of paper feeding may not be good. However, due to the narrow paper feeding width, the impact of this is relatively small.
Fifth, the vertical offset paper is smaller than the horizontal offset blank. When traversing a small offset press, it needs to hold the edge of the paper more, resulting in a certain degree of wasted paper (at present there is no zinc oxide platemaking machine adapted to the cross-feed specification), thus the user's cost of use. It is higher than vertical offset press.
However, for small offset presses of the same specification, the vertical offset offset press has the following deficiencies compared to the small offset press for horizontal feed:
First, because the rollers of vertical offset small offset presses are thicker than horizontal offset offset offset presses, vertical offset small offset presses take longer time than horizontal offset offset presses, thus increasing the speed of small offset presses. , Cross-feed paper has advantages. But for small offset presses, speed is not critical. Both horizontal feed and vertical feed offset presses can reach 10,000 rpm, and normal printing of 6 to 7 thousand revolutions per hour is sufficient.
Second, when a small offset press performs color overprinting, there is a tail-spinning phenomenon. Cross-feeding is relatively short because the paper feed is short and is relatively lighter than vertical-feeding paper. Therefore, color overlay is generally accurate. However, small offset presses, especially monochromators, are unable to truly achieve high-precision color printing (a true high-precision color printing requires a commercial offset press, especially four or more offset presses), so small offset presses The slight tailing phenomenon does not affect the quality of printed products that are normally overprinted.
Third, the phenomenon of pleating will occur during the printing process after the paper is wet, which is a common problem of offset printing machines. Cross-fed offset presses and vertical offset presses are less prone to pleating, which is related to the direction of the paper. Generally, cross-feeding is based on horizontal traverse, and the paper is relatively straight. It is not easy to pleat, and the vertical paper is moved in the forward direction. The paper is weak and may pleat. If the paper is damp, the pleating phenomenon will be more obvious.
The above is the advantages and disadvantages of the cross-feed offset press and the vertical offset press. From the comparison, it can be seen that the cross-feed offset press has more advantages than the cross-feed offset press, especially in terms of cost performance, The advantages are even more pronounced. Arbitrarily speaking, it's good to cross-feed paper or roll paper. They are all one-sided and incorrect.
In response to the shortage of vertical offset paper offset presses, Yingkou Guanhua Offset Press Co., Ltd. has added a number of additional devices on its series of offset presses, such as anti-sweeping roller brush devices and air-sucking belts to convey the paper feed structure, preventing paper from dampness. The front-end and back-end drying devices, etc., which are discounted during the printing process, make the vertical offset press more suitable for the needs of diversified markets, help customers reduce costs and solve practical problems in printing. From the development trend of international offset printing presses, vertical-feeding machines and cross-feeding machines are currently popular internationally. Different customers choose their own suitable products according to their own needs. No one has said which type. The machine is better than the other model.
Yingkou Guanhua Offset Printing Machinery Co., Ltd. is the industry leader in small offset presses in China. In the past 20 years, nearly 40,000 sets of small offset presses have been placed on the market. Judging from our customer base, most of them are suitable vertical offset presses, especially in recent years. In order to meet the needs of some domestic customers, we have also developed cross-feed offset presses. Our aim is to press customers. The request to develop a series of small offset presses with different requirements. (Yingkou Guanhua Offset Press Co., Ltd. Liu Xuezhi)