CTS screen printing computer direct printing plate – making technology

In the Screen printing industry, direct Computer printing is also known as CTS (Computer to Screen), that is, the Computer images directly on the Screen, which is very similar to CTP in offset printing industry.In terms of composition,CTS system and prepress graphic information processing system composition is similar, but the output equipment is very different.

Graphic input section

The graphic input part is to digitize the original manuscript and input various digitized files.

Graphic processing and typesetting

Like DTP, CTS also uses traditional image processing software, graphics processing software and typesetting software, such as Photoshop, Llustrator, etc.

RIP

Like offset printing, THE RIP of CTS is to interpret a variety of graphic file PostScript files, so that the screen output device can understand, and control the screen output device work.

CTS can also accept various design software files as well as EPS and PS files, and can convert the information of these files into various color versions of the dot.

Proofing equipment

Like offset printing, the CTS process also requires proofing for layout check before formal output.

Proofing equipment can be used inkjet printer, or special proofing equipment can be used.

Output devices

Screen output equipment is the focus of the CTS is difficult, domestic CTS less – the main reason is the screen output equipment price is too high and there is no corresponding domestic production technology.

The working principle of the output equipment basically has two categories: one is the laser exposure equipment, through the laser light spot on the painted screen exposure hardening, and then development, so that no light part of the mesh penetration.

This output device has a higher output resolution.Another kind is sprayed Zhao class output devices, output devices the ink jet of high resistance ability of light, in the good photosensitive glue on the screen, then the whole full exposure, blocking light ideas covering the photosensitive adhesive was washed away by did not see the light, revealing the mesh.Its output resolution is relatively low, at 300-600dpi.

According to the specific working mode of CTS screen output equipment can be divided into three types: thermal ink-jet system, ink-jet state transition system and laser exposure system.

Thermal inkjet system

A thermal inkjet system works on the same principle as an inkjet printer.Screen output device with ink image coating on the photosensitive layer, and then screen full exposure, development of screen.

The ink is heated by the heating components in the nozzle to produce bubbles, so called thermal inkjet system.

The heating element is turned on or off by a computer, and when a “point” is needed, the heating element heats to create a bubble whose volume squeezes the ink out and squirts it onto the screen.

On the nozzle to use a row or a matrix nozzle, generally rely on the nozzle to complete the screen output.

Ink-jet state transition system

Ink-jet state transition system using piezoelectric sprinkler continuous ink-jet, ink began to solid wax ball, and then heated to a semi-solid state, spray onto the screen, ink contact screen plate immediately after drying, and then exposure development and other processes.

The ink doesn’t all reach the screen. It passes through a device called a charging switch, called a voltage board.

Voltage plate under the control of the computer can be sent out of the ink bead belt electrostatic, charged and uncharged ink bead through a continuous electrostatic field, the uncharged can be unhindered through the electrostatic field to the printing plate, charged ink droplets in the electrostatic field cause deflection, is collected again.

The advantage of the two inkjet systems is that no vacuum pumping device is required in the traditional screen printing plate-making method. The vacuum device is necessary to ensure the close connection between the film and the screen plate photosensitive layer to reduce image loss. More importantly, the plate can be fully exposed to the screen plate without worrying about the loss of details.

The key problem with both systems is that the ink must be dense enough to block UV light from subsequent exposures.In addition, these two inkjet systems can use the traditional screen printing plate photosensitive adhesive and exposure equipment, and can realize the nozzle cleaning, ink cartridge supplement automation.

But hot ink jet liquid ink is easy to splash, and ink jet state transition mode of ink solidification quickly will not produce splash phenomenon.

Laser exposure system

The output device of the laser exposure system is actually the beam generated by the laser head for exposure, which directly takes the screen plate as the film.The difference between a laser exposure system and an inkjet system is that the laser system uses a laser instead of ink, so it does not require the full exposure step that follows.

The key problem of this system is to have a photosensitive adhesive suitable for laser, which cannot be used for traditional plate making.This system is mostly used in indirect screen printing platemaking process.

In the ink-jet plate-making, drive the special inkjet printing equipment, the text and text information through a kind of liquid hot melt wax with high covering power sprayed onto the coated photosensitive emulsion wire mesh plate, the special hot melt wax light density is high, when the sprinkler will image spray onto the screen plate, hot melt wax immediately solidified, and photosensitive emulsion close adhesion.

Hot-melt ink tasteless, even the use of low solid template materials or low mesh screen can achieve overflow, nondiffusion.The smoother the surface of the template, the better the imaging effect of the template, and the hot wax contains a special ultraviolet blocking agent, which can completely prevent the exposure of ultraviolet diffraction, avoid photosensitive film side wall light corrosion, and then in the screen

After direct exposure and development (washing), the screen printing plate for screen printing can be obtained.

Dot forming can be arbitrary choice of round, square, diamond, oval dot.JetScreen does not have the process of splicing film, and it completely solves the difficult problems such as dot deformation and virtual image caused by objective factors such as image distance and lens spherical difference in magnifying film or screen printing plate. It effectively prevents dot enlargement and ensures the delicacy of image level.At the same time, JetScreen provides an effective solution to the moire produced in screen printing.Large screen printing CTP is not required for film backing, and the size of the spray stencil varies from 1800mm x 2200mm to 3500mm x 5200mm.