Proofing sequence of the hottest gravure proofing

2022-07-31
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Proofing operation sequence of gravure proofing machine

(I) proofing operation sequence of gravure proofing machine installation of proofing materials 10 adjustment of Qee tech new thermoplastic composite material pre forming technology pressure of proofing materials insertion of positioning pin inking inspection of ink viscosity installation of printing plate cylinder setting of pressure of doctor blade positioning of printing plate cylinder application of proofing ink monochrome and multicolor proofing inspection of proofing samples

(II) proofing process of gravure proofing machine, The imprinting cylinder presses the substrate on it against the plate surface, and the substrate adsorbs the ink in the gravure cavity to form an image. The quality of image transfer largely depends on the rubber on the outermost layer of the impression cylinder. The hardness of the outer rubber on the rubber drum of gravure proofing machine is generally 65 shore hardness, which is slightly lower than that of the embossing drum used by printing companies. The pressure distribution produced by the embossing cylinder with different hardness is different. The deformation produced by the cylinder with low hardness under the same pressure is greater than that of the cylinder with high hardness. The elasticity produced by the rubber deformation can cause the elastic deformation of the substrate, resulting in a large area of contact between the substrate and the gravure cylinder, which adsorbs more ink to the substrate surface. For the impression roller with high hardness, the deformation of the cylinder is small, the contact area with the gravure cylinder is small, and the ink absorbed by the substrate is also small. The rubber hardness is different, and the performance difference of the printing in the highlight part is also obvious, especially in the paper proofing, there will be blank spots in the highlight part. This phenomenon is closely related to the V-shaped structure of the electric engraving hole. The British machine adds an auxiliary electrostatic ink absorption device during proofing, which can well solve the problem of high gloss white spots. The registration device occupies a very important position in the concave prototype. First of all, it is required to have a good registration accuracy. Once the registration error is greater than 0. 2mm, the effect of the Electrical Division diagram on the concave sample will be greatly affected. Generally, it is required that the first circle proofing of concave prototype shall not have registration error

a positioning stop gauge under the impression cylinder will stop the impression cylinder at its last stop position after each color is finished. When the impression cylinder is close to the gravure cylinder again, their extrusion point is the same as the last extrusion point, ensuring the precision of proofing. A big defect of domestic copying machine is that it does not pass the standard in registration accuracy. Secondly, the registration device is required to have great flexibility. The length of the gravure cylinder varies greatly. The short cylinder is only 400mm, and the long cylinder may reach 1600mm. Moreover, the overprint line on the cylinder does not have a fixed position. Some are in the pattern, and some simply do not have a overprint line. As long as these version rollers can be installed on the proofing machine, they are required to produce accurate samples for registration. Therefore, the flexibility of the proofing machine registration device is required to be relatively high

the registration mirror of the Japanese machine is fixed on the cross bar on the upper head of the plate cylinder due to wear of the jaw holding the sample. The registration mirror can slide left and right on the cross bar, and the right half of the plate cylinder can be registered. The registration mirror of the British machine is independent. It can push and focus any part of the plate cylinder. Its flexibility is better than that of the Japanese machine

in order to carry out multi-color registration and obtain color proofing effect, the following operation processes must be coordinated:

1 The printing material must be wrapped on the large roller under a certain tension

2. The first color plate cylinder is installed between the top centers of two collets or on the swing arm bearing

3 Move the large cylinder, close to the surface of the printing plate cylinder, rotate to its locking position, and fix it with a pin pin to make it in a safe state

4. Rotate the plate cylinder to align the horizontal gauge line of taohuai town with the horizontal line engraved on the surface of the cylinder

5. The large cylinder is close to the plate cylinder and reaches a certain pressure

6. Check the registration status and repeat until the gauge line is completely aligned

7. Adjust the doctor blade to form a proper parallelism with the surface of the drum, and then adjust it in the vertical direction to ensure good ink scraping

8. Apply the ink to the doctor blade along the surface of the drum, and then pull out the locking pin

9. Drive the large cylinder, drive the driven plate cylinder to rotate, and form an impression at the contact between the large cylinder and the plate cylinder through the doctor blade

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