Image reproduction or transmission is used to visually record information and express ideas and a means of perception, such as painting, oil painting, photography, copy and printing, etc., the printing is the most important image to copy a form.
At present, the printing can be roughly divided into four basic categories: (a) letterpress printing; (b) gravure printing; (c) lithography; (d) silk screen printing.
In today's technology rapid development, all industrial links, silk screen printing is the same, therefore, before learning silk screen printing, understand its relationship with other kinds of printing and the difference is very necessary. Below we first make a brief introduction of the other three printing way.
Letterpress printing method is one of the most ancient. It is the use of a convex surface of letterpress printing. Printing, the printing ink coating on the surface of matrix, and then to stamping on the paper, the font on the surface of the ink is transferred to the paper surface, forming a mark. Hand printing, Lionel whole line typesetting machine printing, stereotype, electric printing and photoengraving belong to letterpress printing.
Gravure printing is by manual or mechanical engraving carved to delimit line, make the print form a concave down a word or a printing method of the image. Printing, first put the ink filling line or groove, reoccupy prepared paper pressure on it, the paper put the ink stick, formation of imprinting. Etching, needle etching and gravure are intaglio printing.
Lithographic printing is also sometimes called chemistry, mean printing images and print in the same plane. It is based on the principle of "oil and water don't mix" implementation of printing. This type of printing is by mechanical or manual image shows in the stone or metal surface, and then to the surface for chemical treatment makes the image part of ink, and other parts of the blank is not close to the ink. Printing, only close the ink on the part of the image is transferred to the paper, form the imprinting. Photocopy of printing, photolithograph and offset printing are lithography.
Modern screen printing not only in technology is different from the other three types of printing, and the four types of printing in one of the most widely application scope. Its printing object can be paper, cardboard, wooden product, plastic, textile, ceramic, metal, fur and after several materials of synthetic materials. It not only can be used for printing graphic objects, and can be printed circle, convex, concave, and irregular shape objects. Because of this, screen printing is an inevitable outcome. However, due to the technical details about it is a commercial secret, its development is in quietly. But anyway, it is in constant progress and development, and broad prospects.
In the process of image transmission development, although there is no special obvious different development phase, but in the screen printing as international industry important role and the creative process, its principle is derived from a simple stencil photocopying. Stencil printing is an ancient civilization, is one of the most ancient image replication method. But it is different from the old stencil photocopying, like the modern era of letterpress printing is different from Gutenberg letterpress printing.
Although the middle of the Japanese people were the first to use hair or silk woven some relaxation without tension template for printing, but the development of modern silk screen printing originated in the United States. Harry from the pioneers of silk screen printing, larry, hite (Harry Leroy Hiett) and Edward owens (Edward A.O wens), silk screen printing as early as the beginning of the 20th century (1901-1906) had already started.Screen printing is first attempt by the United States Detroit, Michigan of the Buddha's soft, Willie (Francis Willette), it has carried on the silk screen printing on fleece pennant is to put the template is attached with a image or pattern on the silk screen printing. Usually screen made of nylon, polyester, silk or metal mesh. When substrates directly under your screen with a template, silk screen printing ink or paint in the middle of the scraping blade pressure through the screen mesh, printing on substrates (scraping blade in both manual and automated).Template of silk screen on the part of the screen hole seal makes pigment can't through the screen, and only the image part can go through, so only image parts have the imprinting on the substrates. Silk screen printing, in other words, in fact is the use of ink penetration of a plate for printing, it is said it was not called silk screen printing mesh printing or silk printing, because not only silk used for silk screen materials, nylon, polyester, cotton, cotton cloth, stainless steel, copper, brass and bronze material can be used as a screen.

In the field of the silk screen printing, equipment, materials, processes and technology is necessary to do a worker prerequisites. This article will from the most basic knowledge of silk screen, make readers have a comprehensive understanding of screen printing.

Net frame
Net frame is silk screen version of a component, often made by wood, have the effect of support screen. Net frame as a component of silk screen printing, there are wooden screen frame and iron frame, and the combination of the two materials. Although many silk screen version have the silk screen version of the factory system, but the silk screen printing operation personnel should know how to make your own net frame, and what type of net frame is best suited to their job requirements. Net frame type and shape is determined by the live parts to be printing, making screen frame, as far as possible using a single one of the best materials, it is helpful to guarantee and improve the quality of printing.
The most common screen frame is flat screen box, it is mainly used for printing on flat substrates. Most of the silk screen printing is used to dry white pine to make the net box or basswood, these materials have no section and other uneven. When buying wood had better choose the material that can meet the requirements of net frame edges. When production size is 36 inch x 36 inch(81 cm x 81 cm) of net frame, the screen frame border, they shall be 2 inches thick and 2 inches (5 cm x 5 cm) wide. For larger screen version, is proportional to the net box the size of the wood to thicken and widened. If net frame is too thin, screen after use, storage and template stretch bending deformation. White pine is the most commonly used screen frame material, but sometimes also use printer mahogany, spruce, boxwood and poison hemlock material production network box.
There are many ways combined net frame. As long as serious production, each method can meet the requirements of silk screen printing. Net frame corners with nails and glue or tighten screw and glue together and excess glue to glue immediately wipe with wet cloth. Nail is must to be used, and the position of the nail to lower some, lest nail scratch template fabric. Pipe network box which combination method, the corners of screen frame should be consolidated with Angle board or Angle, to ensure the durability of it.All net frame Angle must be used sand paper to grind into a circular, all net frame side also want to use sand paper burnish, make sure no any possible damages to the screen of the rough point. If needed, in stretched the net to net frame coated with lacquer or linseed oil, to increase the net frame of the finish. There are four kinds of commonly used method tension network. They are with a pin nails, pressure tank, automatic tension wire mesh machine and commercial patent stretched network technology.
Stretch mesh
During the tension net with a pin to choose 0.5 inches (1.2 centimeters) long flat carpet pin. Silk screen cloth warp to consistent with the long sides of the net frame, because most screen cloth in this direction tension is good, can withstand scraping plate drag back and forth. Also make the fabric with scraping plate drag in the same direction, in order to reduce deformation in the process of printing image. On the screen cloth on the net box, first of all to nail in the middle of the one side of the screen frame, about 0.75 ~ 1 inch between each nail and nail distance network frame 3/8 of an inch (0.95 cm).
Taut wire mesh cloth, first on one side of the screen frame nail a nail. First row in the outside of the nail and be sure to tighten, make hobnail closely contact with wooden frame. Side nails, nail the opposite side, then pay attention to when a nail must tighten by hand. Similarly, other sides of the nails good net box. Finally, in the net frame of the side with the lateral nail nails staggered position on lap, to ensure that wire mesh cloth tightly stretched on the net frame.
After screen cloth was nailed on the net frame, should use different or cold water or contain soap water to clean carefully, it can not only remove any possible rubber, but also contribute to tension wire mesh. When the screen cloth after drying, check whether taut wire mesh smoothing. If somewhere of tight enough, can use a screwdriver carefully remove the nails, the back of the screen, tense here then to nail a nail.Screen cloth must be stretched very tight, otherwise it is difficult to attach screen printing coating or coating emulsions. Some screen printing before the screen cloth coating, lightly with fine pumice or clay to nylon, polyester, silk fiber such as roughness, for the strong bond. But be careful, can abate the elasticity of silk screen. In addition there are many other screen in the actual production cleaning and degreasing method.
Some screen print at the bottom of the screen frame, also is the place where a nail brush on shellac, to prevent ink leakage between the screen and screen frame. Pressure tank net box in the hem of the screen frame has a slot, the slot can use circular saws to dig, can also use a special dedicated chamfer tools or wood chisel to dig. The depth of the slot should be a little deep than the thickness of the plywood. If the plywood is using a hard wood such as maple or birch, its service life is longer, and can be reused. For plywood, about 3/8 of an inch (0.93 cm) is a good size. Its shape can be round or square peg tip stick, be suitable for pressure into the slot.

When stretched mesh, wire mesh by pressing clamp force into the slot. Trough and the edge of the plywood to use emery cloth smooth, so as not to scratch screen during extrusion. Fixed in about 3/4 inches (1.9 cm) of 4 or 5, flat wood wool. Splint on the screw holes should be countersunk, to ensure that when a nail screw head can closely combine with plywood. Hole clearance is about two to four inches.
Tension net before the screen side pressure into the trough, and screw, but not too tight. Across the border in the same degree of plywood, taut wire mesh as much as possible in a fixed, but if some loose at one end of the plate are also no relationship, finally can adjust again. The same method, fixed on both sides of the other. When all the plywood were fixed, sequentially the fastening screws, step by step tight a little at a time, in order to achieve the screen get consistent tension at all points.
With automatic tension net is a very quick and simple way. Stitching machine and nail the same way, and about in the same position, if stitching machine in parallel in the direction of the pull wire mesh cloth, screen cloth will tear. A paperboard cushion can be used in the actual operation on the screen cloth, stitching machine clamp a piece of silk screen cloth and paper, and not directly to pull wire mesh cloth. Doing so not only can avoid the broken screen, and can easily remove the nail pull paper book machine.
Below provides a simple business tension method, whether a beginner or advanced screen printing can get started. This method is suitable for various sizes of wire mesh, but net frame to have the same as pressure tank stretch net frame groove. Stretched the net when the screen cloth on the groove, using tools to a diameter of about 1/8 ~ 3/16 of an inch (0.31 ~ 0.47 cm) of the rope together with silk screen voltage into the slot. Tightening the cord can be repeated for many times. At any time, when the screen cloth must be tighten again, groove can be dug deep some, and then the screen with the same rope to pressed into the grooves.
In the actual screen production process contains a network system. The characteristics of the system is to have a quadrilateral taut independent aluminum frame automatically. The net frame can put the screen tension to the desired degree of tension. And after printing, silk screen can be removed, rolled up and used to mount.
Whether use which stretched mesh method, there are all kinds of already make good net frame for use. But, to be used for special printing products such as printed circuit chemical machinery or special silk screen printing machine, it is best to use patent stretched network equipment, it is helpful to ensure the quality of printing products.
To achieve silk screen printing, screen printing photosensitive agent (or coating) must be attached on a special kind of cloth or silk screen screen printing to generate the required image. To get a good quality of silk screen printing, silk screen selection is very important. It depends on the requirements of printing, the printing quality, template, or how much the details of the types of intermediaries, printing and the surface of the substrates. But whatever the screen material, must have a certain flexibility and intensity, can withstand drag back and forth without tear;It must have a clear reticulate; Mesh and opening must be the same size; Silk screen line cannot have run line; Screen must paint, printing ink, solvent resistance, resistance to cleaning, mask medium, pulling resistance, resistance to rubber, to adapt to the storage conditions, the vibration of the printing press and extrusion, meet the demand of printing in other conditions. In a word, the conditions of the screen is very demanding.
In foreign countries, such as the United States and other countries, silk screen material are mainly silk (tulle), nylon (nylon net), polyester (polyester yarn net), metal processing of polyester (nickel plating polyester silk net), stainless steel, stainless steel wire mesh), phosphor bronze, thin cotton fabric, cotton cloth and some coarse cotton. Used for silk screen line can be made from animal material, can also be synthesized from plant, mineral, material, and the combination of the above several kinds of material to make. Following through all kinds of silk screen printing characteristics, usage, and the practicability of the material is compared with advantages and disadvantages of different wire mesh.

Usually printing is fine, the higher the screen number. However, if the screen carefully, may cause ink through the mesh, or even blocking the mesh. In the case of wire mesh can satisfy the requirement of printing, silk screen printing is as far as possible with coarse mesh. Table 1 shows the used in the context of the given line number on the number of different wire mesh, wire mesh aperture (or degrees), silk screen, as well as the template type.

gauze
Gauze is used for roller printing in screen industry a cloth. Although it is mostly used in foreign countries, but look at it also is very be necessary. Some of the cotton and silk grades of this kind of cloth. It is one of the cheapest cloth, cannot repeat use. It is equivalent to NO. 20 mesh, it is only a paper template of the screen.