The hottest screen printing photographic plate mak

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Screen printing photographic plate making equipment (I)

1 Plate making camera

the plate making camera is mainly composed of an original frame for placing the original, a lens frame for fixing the lens, a focus adjustment cassette and a cassette for placing photosensitive materials connected with the cassette. These three parts are vertical to the ground on the common rack. The original frame and lens frame can move back and forth along the guide rail on the frame, and the ground glass and film frame for light are generally fixed

plate making camera is the main optical machine for shooting all kinds of originals. It can shoot the originals in full size, and can also zoom in or zoom out the originals at a certain magnification

e-ma cost pressure directly affects the power battery il:amyxiang@ jenniferfang@ plate making cameras have a wide variety, which can be divided into darkroom type and cassette type according to the form of installation, and can be divided into manual, semi-automatic and full-automatic according to the degree of automation of operation. According to the position of the underframe, they can be divided into horizontal, vertical and hanging types. According to the size of the shooting format, they can also be divided into full sheet, split, four open Eight open, etc

① horizontal plate making camera. The structure of the horizontal plate making camera is shown in the figure. Its underframe is horizontally placed on the ground, generally including darkroom type and cassette type. Chinese enterprises are talented enough to produce their own plastic extrusion machinery

darkroom horizontal plate making camera. Most of the rack is arranged outside the darkroom, and the rear end of the mirror box is arranged in the darkroom

cassette type horizontal plate making camera, the body is completely installed in the bright room, and the loading and unloading of photosensitive films are carried out in the dark room with a cassette. Because it is inconvenient to move the cassette, this model is mostly used to shoot the base plate with smaller size

the main characteristics of horizontal camera are simple structure and convenient operation, which is suitable for shooting the bottom plate below the Quarto

② hanging plate making camera. The structure of the hanging plate making camera is shown in the figure. Its underframe is hung horizontally in the air with columns, and various parts of the camera are hung upside down on the slide rail of the underframe with iron wheels

the hanging type plate making camera has a large body volume, the working area can be accessed, and it is easy to operate. It is mostly used to shoot large format open and full bottom plates

The underframe of the

hanging camera is easy to lose its level due to the weight of each component, so it is necessary to often correct the water levelness of the underframe and the position of each main component during use

③ vertical plate making camera. The structure of the vertical plate making camera is shown in the figure. Its measuring frame is vertically placed on the ground and covers a small area. It is a small plate making camera. The top of the underframe is equipped with a horizontally movable mirror box, and the lens frame in front of the mirror box is equipped with a total reflection prism. When aiming, you can only move the photoreceptor and the original holder. The lighting device is installed on a rotating cantilever frame

the photoreceptor frame and the original frame of the vertical plate making camera are perpendicular to each other, and the prism added in front of the lens reflects all the original images with a 45 ° slope, and the images are reversed, and then reversed through the lens, so that the negative image with the same direction as the original image is obtained on the photoreceptor

④ composition of plate making camera. Plate making camera is the main tool for photographic plate making, which is composed of frame, original frame, black box,

lens and photographic equipment

a. document rack: used to fix the original, and can move forward and backward to adjust the object distance

b. lens: lens is composed of lens group, lens barrel and aperture, of which lens group is the most important part

The main parameters of the lens are as follows:

focal length: a beam of parallel light converges into a point after passing through the lens, which is called the focus, and the distance from the focus to the center of the lens is called the focal length

image field, image angle: the so-called image field of the lens refers to the photographic ability of the lens, that is, the range of clear images on the photosensitive film. The angle from the periphery of the image field to the node behind the lens is called the image angle

aperture and aperture coefficient of lens:

a) effective aperture: the ratio of the maximum diameter and focal length of the lens

b) relative aperture: the ratio of aperture diameter and focal length at all levels

c) scale of aperture coefficient: aperture coefficient refers to the relative aperture at all levels. The common scale of relative aperture at all levels is: f5.6, 8, 11, 16, 22, 32, 45, 64, 90. The scale of aperture coefficient is based on the reduction or doubling of the luminous flux of the lens for each level of aperture change. For example, if the aperture is increased from F8 to 11, the luminous flux of the lens through the ball screw as the performing element will be doubled, otherwise, the luminous flux through the lens will be doubled

lens resolution: lens resolution refers to the ability to clearly reproduce the smallest part of an object. It is usually measured by the resolution of sand to lines with equal width and spacing under a certain aperture (f11-22), that is, how many lines can be recorded per millimeter

the imaging law of the lens basically conforms to the imaging law of the lens:

p151, where f represents the focal length of the lens; U refers to the object distance, that is, the distance from the original plane to the center of the lens; V refers to the image distance, that is, the distance from the center of the lens to the position of the clear image (the position of the photosensitive film); M indicates magnification or reduction

plate making camera lens is different from general lens, and its characteristics are as follows:

a) the focal length of plate making camera lens is longer than general camera lens

b) the effective aperture is relatively small, generally below f/8

c) the lens used for color separation photography is usually "apochromatic" lens. The lens is marked with "apo". In addition, the plate making lens is also engraved with the film adding mark, "t" (scarlet letter) or "L" in Germany and "C" (scarlet letter) in Japan

c. Dark box: it is formed by connecting two dark box walls with snake pit viper (leather tiger). The front part of the black box is equipped with a lens, and the rear part of the black box is used to receive projected images. It is equipped with light-sensitive glass, suction plate and photographic film

d. Frame: it is the support of the black box and the original frame

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