SU1341448A1 - Radiation source for exposure of photopolymerizing plates - Google Patents

Abstract

The invention relates to lighting technology - to irradiators for the manufacture of photopolymer printing plates, and allows to improve the uniformity of the distribution of the light flux of the exposed surface. The irradiator contains the radiation source 1, the reflector 2, made in the form of a hollow prismatoid, upper, smaller, the base of which has the shape of a square and is equipped with a mirror reflecting dihedral element 4, and the lower, larger base has a rectangle conjugated to the upper base of the reflecting screen 3 The arrangement of the long sides of the lower, larger, base of the prismatoid and the exposed plate 5 during the operation of the irradiator is mutually perpendicular. 2 hp f-ly, 2 ill. (L with 4 4 4; 00

Description

113

The invention relates to lighting technology, in particular to irradiators for making photopolymer printing plates.

The purpose of the invention is povyshenib; uniform distribution of the luminous flux over the shielded surface.

Fig, 1 shows the proposed irradiator, a general view; in fig. 2 - the same, left view.

The irradiator contains a radiation source 1, which is a metal halogen lamp, a reflector 2 and a reflecting screen 3. The reflector is provided with a mirror element 4. Photopolymerizing plate 5 is placed on the exposed surface, with F and M respectively the dimensions of the long and short sides of the plate. The radiation source is characterized by a length L of the bore zone. For DRTI-3000 type lamps, the maximum length of the luminous zone is 105-110 mm; therefore, for a standard format of photopolymerizable plates (420 x 600 mm), the ratio is:

M S g E G 7

The radiation source is located at a distance A from the shielded surface, determined from the ratio

A (1.7 - 1.9) F (2.2 - 2.4) M,

which is determined from the condition of the maximum allowable heating value of the exposed plate by the radiation source and is set in such a way that its axis is parallel to the long sides of the exposed surface and is at the same distance from them.

The reflector is made in the form of a hollow prismatoid, the upper, smaller, the base of which is a square with a side equal to (2-4) L lower, larger, the base is a rectangle, the dimensions of the sides, which are determined from the ratio

C (0.6-0.9) F; K (1.3 - 1.7) M,

where C and K are the dimensions of the sides of the lower base of the reflector, parallel to the long and short sides of the exposed surface, respectively.

five

0

five

4482

From where, after the substitution / ratio of the parameters F and M, we obtain the aspect ratio of the lower, larger, base of the prismatoid, equal to C: K 3: 4.

The reflector height H is (0.3 - 0.7) A or (1 - 1.5) K.

The mutual arrangement of the irradiator and the plate 5 (Fig. 1) shows that the projections of the long sides of the base of the przmatoid and the exposed plate on the exposing surface are mutually perpendicular.

The mirror element 4 is made in the form of a dihedral angle, the edge of which is directed downward, parallel to the long side of the lower base of the prismatoid and perpendicular to the axis of the lamp located beneath it.

The inner surfaces of the reflector and reflective screen are made of diffusely diffusing material.

The irradiator works as follows.

The irradiator is placed above a vacuum plate (not shown). A photopolymerized plate 5 with a negative placed on its surface is placed on a vacuum plate, its polyethylene film is closed, the vacuum is turned on and, after reaching a pressure in the system, no more than 300 hPa (0.3 MPa), the irradiator is turned on. Exposure is carried out for the required time, then the irradiator is turned off, the vacuum is turned off, the polyethylene film is removed, the exposed polymerization plate 5 is removed and the negative is separated from it. The exposed photopolymerizable plate 5 is directed to leaching.

The proposed irradiator (in comparison with the known) provides

uniform distribution of the light flux 5 over the surface of the exposure, as evidenced by the obtained optimal profile of the printing elements: their cross section is an isosceles trapezium with an angle of 0 at the base within 65-75. In addition, the use of the proposed irradiator allows the simultaneous exposure of two or more photopolymerization plates.

Claims (3)

1. An irradiator for exposing photopolymerizable plates containing 313 a radiation source, a reflector and a reflecting screen, the upper base of which is paired with the lower, large, reflector base, which is so-called that with the aim of increasing the uniformity of the light flux distribution over the exposed surface, the reflector is made in the form of a hollow prismatoid, upper, less the neck, the base of which has a square, the lower, larger, base is the shape of a rectangle with an aspect ratio of 3: 4, and the height of the reflector is 1 -. 1.5 side lengths of the lower base. 2. The irradiator according to claim 1, characterized in that the upper base of the prismatoid is provided with a mirror reflecting element in the form of a dihedral angle with an edge directed to the exposed surface and perpendicular to the longitudinal axis of the radiation source, 3. The irradiator according to claim 1, characterized in that the inner surfaces of the reflector and the reflecting screen are made of a diffusive-diffusing material. Editor A. Revin Order A423 / 43 Circulation 465 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4  FIG. 2 Compiled by G. Velichkina Tehred I.Popovich Proofreader. Cherni Subscription