The new gravure proofer has been continuously exploring the actual printing production process (embossing form, ink, printing materials, etc.) and has taken a series of improvement and assurance measures to reflect the quality of the drum as faithfully as possible. D.
Since the technical performance of the gravure proofer itself has been continuously improved in the past 10 years, the more popular the machine proofing, the rapid development in recent years. The following describes the gravure proofer of a famous manufacturer as an example.
Second, gravure proofing machine Introduction 1, the main technical specifications on the market at present on the gravure proofing machine for the largest plate roller surface width up to 4000mm, plate roller circumference up to 2200mm, so its width and circumference can cover all Gravure fields (see Table 1).
In order to make the proof reflect the actual gravure effect better, the length of the general proofing is at least two graphic lengths. Therefore, the standards for proofing are five-pointed star work, respectively, 2100mm, 2600MM, 3500MM and 5500MM.
2. Applicable occasions The gravure proofer has been able to meet the practical needs of various types of gravure printing machines, and is suitable for printing cylinders of various widths and lengths. There are currently gravure proofers for the following machines on the market: packaging gravure printing presses, publishing gravure printing presses, wallpaper gravure printing presses, gift gravure printing presses, decorative gravure printing presses, and the like.
3, proofing conditions Gravure proofing machine proofing the use of printing materials and printing materials used in the actual printing the same, the ink used is similar to the actual printing ink used, but the use of low solvent content. The gravure printing machine used in the actual production generally consists of a plurality of printing color groups, but in most gravure proofing machines, only one unit of the actual printing machine is simulated, that is, a monochrome machine.
4. The mechanical structure gravure proofer is mainly composed of the following parts:
(1) Supporting Mechanism of Plate Roller The supporting mechanism of the plate cylinder adopts conical tip or butterfly chuck system. The former is used for the proofing of small sleeve rollers. The applicable printing roller has a circumference of 200-750mm. The latter can be used by an operator to load and unload the plate cylinder and the cleaning device. The air motor can drive the friction pad to prevent the plate cylinder from moving or rotating. This system is suitable for various sizes of plate cylinders, especially for shaft type plate cylinders and sleeve type plate cylinders. The system is simple and flexible, and it is especially useful in drum proofing.
(2) Cleaning system The cleaning system adopts pneumatic transmission and can be used for shaft type plate cylinder and sleeve type plate cylinder. The system is simple and flexible, and it is especially useful in large drum proofing.
(3) Static-assisted ink transfer device A device is particularly suitable for printing materials that are difficult to print. Due to the textured structure of such materials, it is very difficult to print subtle layers. With static-assisted ink removal devices, this can always be overcome and the proofing effect can be comparable to actual gravure printing.
(4) Registration system with display The system uses electronic double crosshairs generated on the screen to adjust the parallelism error. This system is used to compensate for progressive drum changes.
(5) Large rubber roller The surface of the large rubber roller is coated with printing material. Although it is not an impression roller, it is in contact with the plate treatment tube to generate pressure, and there are mechanisms to ensure that a certain pressure is controlled and adjusted at both ends.
The proofing cartridge is placed between the top centers of the two chucks or placed on the swing arm support roller bearings. The proof drum is close to or opposite to the drum. The length of the printing material is 2-3 of the circumference of the printing plate cylinder, so as to form a good simulation of the continuous production process of the web.
(6) Squeegee The squeegee on the gravure proofer is the same as the squeegee actually used on the gravure press.
The technical characteristics and operating advantages of the gravure proofer are: The hydraulic drum is used for large drums and plate cylinders. The structure of the drum is precise, the system is easy to operate, almost no maintenance is required, the balance of the imprinting force at both ends is balanced, the register control is precise, and the gravure printing machine is simulated. The effect is good. The machine can complete the proofing operation within 10 minutes by one person, which can reduce the amount of ink and materials, and can intuitively and accurately detect the drum engraving quality.
5, register control'
In order to carry out multi-color registration and obtain color proofing effects, it is necessary to coordinate the following several years of operation:
(1) The printing material must be wrapped onto a large roller under a practical tension;
(2) The first color plate cylinder is installed between the top of the two chucks or the swing arm bearing;
(3) Move the drum, close to the surface of the plate cylinder, turn it to its locking position, and fix it with a pin to make it safe;
(4) Rotate the plate cylinder and align the horizontal gauge line of the register mirror with the horizontal gauge line carved on the roller surface;
(5) The large drum relies on the plate cylinder and reaches a certain pressure;
(6) Check the registration status and repeat until the gauge is fully aligned;
(7) The squeegee is adjusted to the roller and the tamper tamper. The sodium is called unloading. The squeegee is written by the squeegee. The squeegee is written by the squeegee. (8) The ink is coated on the roller. The surface of the squeegee, and then pull out the locking pin;
(9) Drive the big drum to drive the driven plate cylinder to rotate. Through the squeegee, the "printing" is formed at the contact between the big drum and the plate cylinder.
The ink is transferred from the ink hole through the pores to the surface of the printing material (in some cases, the proofer does not use an electrostatic assisted transfer device). The drum rolls to the end of its circumference to get the largest sheet. After the rotation is completed, the large drum leaves the surface of the plate cylinder, and the plate cylinder can be cleaned and disassembled.
The color proofing after the second color is repeated after the previous color is dried and the same process as described above is repeated.