Rotary screen printing plate-making technology

According to the design spirit of flower patterns, we must first determine which printing process to adopt. Because the printing method used is different from dyes, auxiliaries and pastes, the drawing method chosen is also different.

When using manual color separation, we should reasonably consider line separation, line borrowing, line merging and overprint, and strictly control the outline size, blank size and line separation size. Fine patterns have high requirements for flowers, with even arrangement and delicate patterns, so as long as one aspect of the whole picture is missing, it will affect the overall printing effect, so the colors must be handled reasonably.

The size control of contour size, grey cloth size and parting size depends on the fabric structure and thickness, pattern structure and size, color depth and the selection of rotary screen mesh. In general, when printing with reactive dyes and disperse dyes, the pattern with large size will shrink by about 0.02 mm. For high-precision patterns, the shrinkage rate is 0. 0 1 -0.0 15mm due to the high mesh rotary screen.

For geometric patterns, computer color separation plate-making system should be adopted. It is important to note that the perimeter size of the film separated by computer must be the same as that of the nickel mesh, so as to avoid the dislocation of the flower position and seriously affect the fineness of the pattern.

For moire, ink stains and watermark patterns with particularly full levels, it is generally appropriate to combine manual description with computer color separation, or completely manual description, or to combine with traditional photography techniques. Because for some difficult patterns, it is still difficult to completely rely on computer color separation, and some performance contents and means are beyond the scope of computer color separation.

The factors that affect the quality of plate making include the final contact cleaning of net blank, the quality of photosensitive adhesive, the thickness of sizing and the uniformity of exposure time.

(1) Do the final contact operation of rotation. After the rotary screen is coated with photosensitive adhesive, the low-temperature drying time should not be too long, so as to avoid blocking the screen by the initial polymerization and curing of the adhesive.

(2) When preparing photosensitive adhesive, strictly control the dosage of various chemicals and master the consistency of photosensitive adhesive.

At present, there are two kinds of photosensitive adhesives on the market: fogging and flaking during development. When the photosensitive adhesive falls off in sheet form, the carved pattern outline has a "sawtooth" effect, the printed lines are not clear and smooth, and the style of fine patterns is lost. Therefore, the photosensitive adhesive that falls off in mist form should be selected.

For fine printing, the photosensitive adhesive layer on the nickel screen should be thinner. The thinner photosensitive adhesive layer can make the moire pattern get rich layering and make the fine lines clear and full. Above a certain thickness, the depth of photosensitive adhesive layer can not be cured, and excessive curing will degum. Therefore, before coating, the photosensitive adhesive should be diluted with distilled water or alcohol, dipped with a glass rod, and flowed down in a continuous thin line.

Domestic JR 105- 1 and JR 107 rotary screen photosensitive adhesives are suitable for plate making and photosensitive of high mesh rotary screens.

(3) The coating speed of scraper and the insulation temperature of rotary screen should be appropriate. In general, the coating speed of scraper is 10-I2cm/min, and the maximum speed cannot exceed 15cm/min. The temperature of the rotary screen is controlled at 40-5090. The suitable gluing speed for fine patterns is 8-9 cm/min.

(4) After development, it can be soaked in hot water at 40-50℃ for about 20 minutes in a horizontal developing tank, so that the unexposed adhesive layer expands and dissolves, and finally the expanded but not completely detached adhesive film is brushed off with a brush. Only in this way can the grid be clear and the printing paste be transferred to the fabric smoothly.

Exposure is also the key to making fine patterns. Practice has proved that the exposure times of fine lines are not enough, the curing of photosensitive adhesive is not firm, and it is difficult to develop lines because of too many times. It is appropriate to control the exposure times of fine lines at 4 times.