Gao Bao Libida 104 tooth abnormality caused by ghost analysis

Gao Bao Libida 104 tooth abnormality caused by ghost analysis

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After a period of use, a KBA Rapida 104 has different degrees of ghosting when printing four colors, especially when printing coated paper of 105g/m2 or less.

Ghosting phenomenon 1: The printed sheet slides on both sides of the corner, causing overprinting. This phenomenon occurs when the device is used for about one and a half years.

Analysis of the cause: After inspection, it was found that the force of the entire row of impression cylinders was insufficient, and the single jaws were stiff or had broken teeth. Upon further inspection, it was found that the contact surface of the copper band of the molars and the long axis of the open teeth was rusted. The reason for the rust is that the water in the gasoline enters the braces when the operator cleans the ink and paper powder on the surface of the impression cylinder, and the rust is long. Due to insufficient squeezing force, the paper is ejected during the printing process, which causes the corners and overprinting.

Solution: (1) first loosen the eccentricity of the open ball, then loosen each braces, remove the rust, point the oil, restore each tooth to its original position, and finally adjust the force of the force to restore the eccentricity of the tooth. Position to ensure the pressure of the entire row of teeth. (2) When cleaning the surface of the impression cylinder, the oil-water mixture should be avoided as far as possible to reduce the possibility of rust.

Processing result: After finishing the work of cleaning and adjusting the cavities, the printing is restarted and the ghosting phenomenon disappears.

Ghosting phenomenon 2: When the large offset printing is changed, the two sides of the printed sheet appear from the mouth to the tip of the tail. This phenomenon occurs two to three years after the equipment is put into production.

Analysis of the cause: When printing the printed sheets, the fangs of the embossing cylinders other than 780 mm are temporarily used. The rubber pads of these fangs and the pads are in direct contact for a long time, and the rubber pads are smashed by the fangs. At this time, the contact ability of these cavities with the dental pads is basically lost. When the printing is big, the squeezing force of these fangs on both sides of the printed sheet is almost lost. Together with the printing pressure and the viscous ink, the paper is ejected on both sides of the printed sheet, which causes a ghost phenomenon.

Solution: Replace the new tooth pad. But each original tooth pad is about 400 yuan, the price is more expensive, and sometimes there is no stock in China, it needs to be imported from Germany, so it is necessary to say that it takes two weeks, the production loss caused by the shutdown and other parts is too great, and the wear resistance of domestic parts Not enough. Later, after research and experiment, we used ordinary 502 glue and domestic suction nozzle apron to make a dental cushion that is comparable in function to the original dental cushion. Clean the base surface of the dental pad, cut the apron, polish the apron contact surface, firmly adhere the leather pad made of the apron to the dental pad with 502 glue, then polish the leather pad, level with the surface of the impression cylinder, and finally adjust the whole The drainage force is consistent. It takes only 5 minutes before and after such a dental pad.

Processing result: restart printing, ghosting disappears.

Ghosting phenomenon 3: The printing of the mouth of the sheet to the middle of the tip or half of the printed sheet from the front to the back caused a serious overprint error and caused a ghost. This phenomenon occurs three to four years after the equipment is put into production.

Analysis of the cause: The rubber pad of the middle part of the embossing roller or part of the tooth pad is seriously worn, causing a large amount of fangs to be obviously insufficient, almost losing the due force, and a large area of paper ejection occurs in the printed sheet, which causes serious overprinting. error.

Solution: As with the second solution of the ghost phenomenon, use 502 glue and apron to repair the pad rubber pad. The difference is that the number of pads is more repaired. Finally, the whole row of teeth is adjusted. .

Processing result: restart printing, ghosting disappears.

Estimation of economic benefits: Workers who have done these adjustments and repairs can achieve direct and indirect economic benefits.

Direct economic benefits: If you buy a new tooth pad, it costs about 70,000 yuan for each 400 yuan, 21 rows, and 8 rows. A bottle of 502 glue and a dozen aprons cost only a few dollars. Savings of more than 70,000 yuan.