17 cases of direct flexo printing failure of the h

2022-08-11
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17 cases of direct flexo printing failure of corrugated boxes (1

Direct flexographic printing corrugated boxes are more and more favored by people because of their bright colors, rich layers, high definition, low production cost, short delivery cycle, environmental protection and other advantages. However, in the printing process, due to the influence of equipment, flexographic, ink and human factors, various problems are bound to occur. This paper objectively and comprehensively analyzes the common problems and solutions of direct flexographic printing of corrugated boxes Analysis, for the reference of corrugated box printing enterprises

1。 Causes and solutions of inaccurate overprint:

(1) the manufacturing accuracy of the printing machine is not high, or the machine is worn (especially the machine with gear transmission). The orders are arranged according to the production capacity of the machine, and the orders with high requirements can be arranged on the printing machine independently driven by the servo motor. If the machine is worn, replace the worn parts

(2) there are foreign objects in the machine. Remove foreign matters

(3) the tensile deformation of the printing plate is inconsistent during plate loading. Before plate loading, check whether the plate making dimensions of the two plates are consistent, and ensure that the tension of the two plates is consistent

(4) the tensile deformation of the printing plate is inconsistent during printing. According to different printing pressure and printing area, the current electronic universal testing machine of Jinan new era assaying Instrument Co., Ltd. has the following three performance characteristics: the stretching degree of the whole printing plate

(5) use the old and new printing plates together. When redoing the new version, we should consider the effect of the old version

(6) cardboard warpage. Reprocess the paperboard before putting it on the machine, or reduce the printing speed

(7) the paperboard is wet and soft, or the paperboard is too smooth. Increase the air suction or paper wheel pressure. If the printing area is small, add paper strips on both sides

(8) the printing pressure is light, or the pressure of the paper wheel is light. Appropriately increase the printing pressure or the pressure of the paper pulley, or paste a layer of heavy sponge on the paper pulley

(9) insufficient vacuum adsorption. ① Check and empty the dust filter bag; ② Block the air inlet outside the cardboard; ③ Replace with transparent, 1. Raw dust filter bag

2。 Overprint

causes and solutions C. dual report: fully open user report:

(1) the ink of the previous color is not dry or the ink layer is too thick. Improve the drying speed of the previous color ink: ① reduce the viscosity of the previous color ink: ② reduce the thickness of the ink layer; ③ Add an appropriate amount of quick drying agent; ④ Reduce the printing speed; ⑤ Reduce surface tension; ⑥ Increase the drying temperature

(2) the viscosity of the last color ink is not enough. Adjust the viscosity of the later one color ink to make it higher than that of the previous one

(3) the last color ink dries too fast. Reduce the drying speed of the second color ink: ① add slow drying solvent; ② Turn off the dryer; ③ Improve printing speed

(4) the pH value of the last color ink is too high or too low. Adjust the pH value of ink, or replace

(5) the latter color and the top note with fresh ink

3. Dirty

color inks are incompatible. Ask the ink supplier Association for help

causes and solutions:

(1) the ink is not dry or the ink layer is too thick. Improve ink drying speed: ① reduce ink viscosity; ② Reduce the thickness of ink layer; ③ Reduce the printing speed; ④ Reduce the ink transfer volume of the corrugated roller; ⑤ Gradually increase the drying temperature

(2) uneven bottom ink layer, such as ghosting, uneven color, etc. Adjust the printing pressure, and check the parallelism of each drum wheel and the flatness of the printing plate

(3) the surface tension is too high and it is not easy to dry. Replace the solvent or ink

(4) the die-cutting pressure is too large, or the die-cutting pad is worn. Remove the die-cutting glue (protective cover), replace the die-cutting knife, reduce the die-cutting pressure, or replace and adjust the die-cutting pad.

(5) the folding box belt is worn or loose. Replace or adjust the folding belt

(6) the paper guide wheel, guide rod, etc. touch the printing part, or the stacker belt touches the printing part. Move or adjust the paper guide pulley, guide rod and stacker belt to minimize the middle strike

4。 Dirty spots (blockage)

causes and solutions

(1) excessive printing plate pressure. Reduce plate pressure

(2) the pH value of ink is too low. Check and adjust the pH value of ink

(3) the ink layer is too thick or uneven. Reduce the thickness of ink film: ① reduce the ink and control its output viscosity such as angular wave, square wave or sine wave by computer; ② Increase the scraper pressure; ③ Reduce the ink transfer volume of the corrugated roller

(4) the ink dries too fast. Reduce the drying speed of ink: ① add slow drying agent to reduce the drying speed; ② Turn off the hot air drying equipment; ③ Improve printing speed

(5) the number of lines of the embossing roller does not match the number of lines added to the printing plate. Select the corrugation roller with appropriate number of lines

(6) the relief of the printing plate is too shallow. The height of relief and the thickness of subbase should preferably be 2.00mm

(7) paper scraps accumulate on the printing plate or in ink. Wipe the plate, remove the paper scraps,

no benzene, formaldehyde and other harmful materials, and replace the ink when necessary

(8) the space between Fonts is too small and the anti white is too light. Check the film density and reduce the main exposure time, or mask some printing plates

(to be continued)

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