How to deal with the quality failure of corrugated board printing presses
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
The printing equipment of corrugated board printing machine integrates the functions of printing, slitting and indentation production. The equipment has simple structure, small floor space, simple operation method and easy control of quality. It plays a certain role in the carton production process. However, if the equipment is aging or the machine is not properly adjusted, some quality problems are likely to occur during printing. The classification analysis is as follows:
First, the layout of the text appears dirty, paste or local graphic imprinting quality failure
1. Quality failure caused by poor machine embossing related parts:
When the plate cylinder head, the platen roller head, the drive shaft, the gears, and the critical components associated with the embossing are worn and loose, the plate cylinder or the embossing roller may pulsate or slide during the embossing process. Phenomenon, the contact between the printing plate and the paperboard is not normal (that is, the pressure is unstable), resulting in a plaque or partial graphic imprint of the cardboard printing plate. In this regard, through careful observation and analysis, the exact location of the fault should be ascertained, and corresponding measures should be taken to deal with it, and the worn and loose parts should be repaired to eliminate the fault phenomenon.
2. Quality failure caused by poor ink roller:
When the inking roller shaft head is loose, the inking roller body is bent, deformed or damaged, and the dirty plate, paste or partial graphic imprinting of the printing plate may be unclear. After the cause is identified, the corresponding measures are taken to maintain uniform and appropriate contact conditions between the inking roller and the printing plate, and the damaged inking roller can be replaced to eliminate the malfunction.
3. Quality failure caused by improper adjustment of pressure roller:
If the position of the pressure roller is too high or too low, the contact with the corrugated board is too tight or too loose, and the dirty plate, paste or partial graphic imprint may be unclear. At this time, the proper position of the pressure roller should be adjusted so that the gap between the pressure roller and the roller is adapted to the thickness of the cardboard to ensure that the ink color of the printing plate remains clear.
4. Quality failure caused by unsuitable position of the paper feed roller:
If the position of the paper feed roller is not adjusted, the printed paperboard is in the process of conveying. Since the print on the paperboard has not been dried, after being rolled by the roller, the transfer phenomenon will be caused, and the blank layout on the paperboard will be dirty. In this case, the problem of the malfunction can be avoided by adjusting the paper feed roller to the portion of the cardboard that has no printing surface.
5. Quality failure caused by improper color sequence:
If the full-page graphic is arranged in the first color group printing, when the corrugated cardboard enters the second color group mechanism printing process, since the printing image of the first color on the cardboard is large in ink volume and slow in drying speed, It is extremely easy to transfer the print and cause the layout to get dirty. As long as the layout of the small area is arranged in the first color group printing, and the layout of the large area is arranged in the back color group for printing, the occurrence of the failure can be better avoided.
6. Quality failure caused by uneven thickness of the printing plate:
When the thickness of the rubber plate is not uniform, the plate layout will have a height difference. The place with a high layout is easy to paste, and the place with low layout is prone to incomplete ink, which makes the imprint unclear. In order to avoid this unfavorable situation, the same plate should be used for the production of small pieces (such as the plate making process that saves the rubber plate without the plate core). They are made separately so that the thickness difference is relatively small. If the rubber plate is already prepared, if there is a difference in thickness, a layer of tape may be adhered to the back of the thin partial printing plate to maintain a substantially uniform thickness of the entire printing plate to ensure the printing pressure and the thickness of the corrugated cardboard of the printing surface. The quality caused by unevenness.
After forming the corrugated cardboard, if the surface is damaged by the dents, the paper surface of the depressed portion may also show unclear quality defects. If this is done by using a comprehensive increase in printing pressure, it is prone to the ills of text and line layout. In order to avoid this situation, corrugated cardboard should be handled lightly, lightly and gently (in order to control the stacking height) during stacking and handling. Do not use bad production habits such as throwing, smashing and pressing.
Second, the layout of the graphic printing position is not accurate or unstable quality failure
1. The printing position caused by corrugated cardboard is not allowed:
If the corrugated board has a bad condition, then the corrugated board is prone to slippage during the positioning and feeding process, and may even cause the rules on the machine to not touch the edge of the paper, causing the printing position of the cardboard to be inaccurate or not. stable. Therefore, for the corrugated cardboard of the curved warp, when printing the paper, the relatively flat paper edge should be used as the positioning paper edge. In addition, attention should be paid to the control of the good quality source, through the reasonable mastery of the single-sided machine operation process, so that the speed of the machine and the preheating temperature, the moisture content of the base paper and the preheating area are relatively in a coordinated state. At the same time, when distributing paper, it should be noted that the cardboard paper and corrugated paper with similar water content are matched and synthetic, so that the corrugated cardboard produced is relatively flat, which can effectively ensure the registration of printing.
2. The printing position caused by improper operation process is not allowed:
If the position of the plate is not correct, it is easy to cause the printing position of the layout to be inaccurate. Because corrugated cardboard with curved defects just enters the plate cylinder, even if there is a slight slip phenomenon, the tip of the cardboard will be obviously deflected. Therefore, the corrugated cardboard should have a coloring layout on the side of the roller as far as possible to position the paper, and determine the position of the plate to improve the overprinting accuracy of the corrugated board.
3. the positioning caused by machine failure is not allowed:
When the chain, rules and other components of the machine are loose, it is easy to cause the printing position of the layout to be inaccurate. For this reason, corresponding measures should be taken to repair, and the looseness of the parts can be eliminated to ensure the accurate printing position of the corrugated board.
Third, the indentation line on the cardboard is not clear
The indentation of the printing press is achieved by pressure rolling at the corresponding points of the male and female wheels, wherein the shaft of the concave wheel can be adjusted to maintain the clearance required for the indentation with the male wheel. If the concave wheel is adjusted too low, it will cause insufficient pressure to make the indentation line unclear. In addition, if the shaft of the convex wheel and the concave wheel is loose, the indentation line may be unclear. Therefore, after the cause should be identified, appropriate measures should be taken to adjust and deal with it.
Fourth, the paper edge is not neatly cut, and the edges appear rough.
The slitting of the corrugated board by the printing machine is completed by the upper and lower circular hobs. When the circular slitting cutter is blunt or the blade is cracked, the contact between the upper and lower slitting cutters is not tight enough, the upper and lower cross-cutting depths between the slitting cutters are insufficient, and the shaft portion of the slitting cutter is loose. It is easy to cause the cutting of the cardboard to be irregular, which causes the edge of the cardboard to appear rough. Therefore, in order to ensure that the paper edge is cut neatly, the cutting knife is blunt and must be sharpened immediately to keep the blade sharp. For the slitting knife that cannot be sharpened and repaired by the blade, the new blade should be replaced; if the machine is loose and the discomfort is adjusted, corresponding measures should be taken to deal with it.
The above-mentioned quality failure phenomenon is caused by the cause of equipment failure, and also caused by improper operation. Therefore, it is necessary to carefully perform proper maintenance of the equipment and properly control the printing operation technology to effectively prevent or reduce various quality. The occurrence of failures has resulted in a simultaneous increase in production efficiency and product quality.