Intaglio printing is mainly used in food packaging, leather, cigarette packaging, building and household adornment material, floor materials, fabrics, such as a wide range of areas. Gravure print gloss high, tinting strength strong, bright colours, transfer and superimposition performance is good, printing density is high, the contrast, the gradual network expand equilibrium, plate printing resistance force is high, the printing speed etc advantages.
Many domestic manufacturers use gravure plate making many ways, but in recent years with the rapid increase of printing plate-making technology, digital process gradually dominate the market mainstream.
According to the current actual situation, the number of gravure plate making have three ways:
(1) electronic engraving machine way;
(2) the laser cutting film and corrosion treatment;
(3) plating alloy laser direct ablation process mode.
A, electronic engraving machine way
Electronic engraving machine is the application of integrated automation control of modern technology, with high quality stability of precision machinery. To German Hell machine as an example, sculpture frequency 4000 hz - 8000 hz line range: forty - 140 line/cm, manuscript after separating production, through the RIP in 1 - BitTiff graphical format or bill unit sent to electric carving machine workstation, through the digital signal drive diamond engraving needle in plate copper drum surface vibration, carved out of the pit. Diamond engraving head is rectangular pyramid shape. Electric carving head hit the v scallops have not only the change of depth and size changes, thus completed by half tone reproduction.
Electric carving all production data in digital form collection, can be in the subsequent live one in use, reliability. Manuscript from the scanning began to become digital signal let off software separations and transmission to electric carving machine or color proof machine, it is in the production process of standardization and standardization is very favorable, so as to ensure the quality of printed matter more. And electric carving workstations use TIFF graphic data transfer, after HelioLight group edition workstation for convenient integration and set working parameter configuration, by carving software produce electric carving curve, record electric carving parameter and display carving state until the CD save file (many convenient use and revision).
Electric carving process relative mature, simple control, hierarchical reduction lifelike. Defect is the field of ink in quantity is limited, ink layer for some rough printing content covering power shortage; Due to mechanical engraving nets hole and net hole between the WangQiang segmentation, a net hole composition line edge inevitable serrated appearance, small text when printing not clear and easy break or paste version. But the German haier recently launched a new Xtreme sculpture technology, it can be as high as 400 line/cm line number very fine reproduction of the most subtle part, fine words don't rely on carving screen ruling and independent selected record resolution, by optimizing the ink flow contour smoothing and produce contour line. Not only can realize the conventional network, also can realize frequency modulation and network copy.
Electric carving equipment manufacturers in addition to Ohio, Germany haier, Japan screen and Switzerland MDC products more mature outside, domestic manufacturers have developed a similar performance of the product.
Second, the laser cutting film and corrosion process
Laser cutting film and corrosion process is relay carved later an advanced digital process way, it and electric carving the interface accept separation processed image file, and add the graphic signal sent to the laser modulator, laser effect on roller surface prepainted cover and make copper or iron bottom out, again after different time of corrosion in the roller forming size different outlets pit.
To German west buss · Ohio SCHEPERS may, for example, use YAG (Nd3 + : YAG) solid laser, laser power is not higher than fifty w, the lens focus into and μ of spot.
Laser break roller surface black glue, residue by suction tube into the collection bag, the remaining black rubber in the roller surface formation corrosion protective layer, and the last in the tank corrosion control FeCL3 solution concentration and spray time, in the copper layer or iron roller surface formation depth conformity and different sizes of the network.
Laser cutting membrane technology to overcome the electric engraving words and fine hair line, breezing weaknesses, highlighted with ink volume is high, color thick, writing clear, durable characteristic, with the traditional gravure plate making and compared with a net increase of high accuracy, can edit mesh, no joint etc. Suitable for smoke edition, anti-counterfeiting printing words are so small but requirements definition high plate, is widely used in currency, securities, ticketing and high precision security printing and high-grade wine and tobacco packaging, in fine embossing roller and glue roller production process more advantage.
In addition to a sensitizer laser mode, using the purple laser to graphic part of the sensitive layer exposure rinse again. Other process with laser cutting film basically the same way.
Three, electroplating alloy laser direct ablation process mode
The present market application have D ō wyler company DLS (Direct - Laser - System) System, high-power YAG pulsed Laser irradiation with no contact way the surface of the roll will be galvanized zinc layer gasification and the formation of network, and hard chromium plating can finish the whole process, select the zinc because its physical properties (melting point, boiling point, hardness) and reflection characteristics than copper more suitable for Laser ablation. DLS system support general PS, PDF, TIFF data format, through adjusting each laser pulse point of energy and focus diameter to generate different size, different depth points, the biggest site 140 μ, deep and μ, mainly used cigarette packet and anti-counterfeiting printing. Laser ablation technique in intaglio with the wide application of laser technology development and rapid popularization, it does not need mechanical adjustment, fine lines and words more clear, more easily than corrosion control level.
At present the German HELL company also launched a new laser engraving machine, Cu - Diretlaser system. It used high resolution laser direct in bronze drum surface fine carving. Can arbitrarily change the engraving of the outline of information, network distribution and depth, so as to realize the past only image setter can achieve output effect.The advantages of digital process technology
Digital process is original in duplicate to the plate in the process of color information to digital signal in the form of transfer. Its main advantages are:
(1) the simplified the process flow, making good graphic files through the computer control can get plate;
(2) reduce the plate making direct cost, eliminating the use of the film cost;
(3) to reduce the color reduction process signal loss, is more advantageous to the color management;
(4) to solve the graphics in the roller continuous seamless splicing, for decoration, textile, and other fields practicability strengthened;
(5) format size change more freedom, the current domestic can system 2800 mm x 2000 mm wide, does not need the plate by phototypesetter output film limit,
6 in the same drum for the implementation of multiple process to provide accurate positioning, the same edition can have different line number, different line Angle outlets.