JPH0410602Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a variable magnification type copying machine, and more particularly to a structure for adjusting the light distribution ratio within an optical path cross-sectional area in a variable magnification exposure device.

Prior Art As is well known, in a slit exposure type copying machine, as shown in the principle diagram of FIG.
A lighting lamp B, multiple mirrors C, D,
E. Use an in-mirror lens F (sometimes a through lens) to scan the original G on the original platen glass A.
The image is formed on a photoreceptor H to form a copying machine. By the way, in such a slit exposure type optical device, when changing the copying magnification, for example, the position of the second mirror D is moved in the direction of arrow α to change the overall optical path length, and the position of the in-mirror lens F is moved in the direction of arrow β. The focal length can be determined by changing the direction, but if the copying magnification is changed, there is a problem that the light distribution ratio between the central part and the peripheral part of the slit changes depending on the magnification. For this reason, conventionally, for example, patent applications filed by the applicant
A variable magnification exposure apparatus as shown in the application No. 58-188747 has been proposed. That is, in this variable magnification exposure apparatus, a frame forming a slit opening is located in the middle of the optical path of the exposure optical system, and a plate-shaped light shielding member that can intervene in the slit opening is pivotally supported on the frame. is made to respond to the position of variable elements such as the lens mounting plate. Therefore, according to this variable magnification exposure apparatus, the position of the light shielding member is automatically adjusted according to the copying magnification, so that the proportion of the amount of light passing through the slit opening is corrected according to the copying magnification. However, according to such a structure, the position of the light shielding member is uniquely determined by the operating member provided on the lens mounting plate, etc., and the relative position of the light shielding member with respect to the operating member. If there are processing errors or assembly errors, a predetermined light distribution ratio cannot be obtained, and it is almost impossible to make adjustments after assembly.

Purpose of the invention In view of the problems of conventional variable magnification exposure devices as described above, the purpose of the present invention is to create a slit according to the copying magnification even if there are processing errors or assembly errors in the components of the variable magnification exposure device. The purpose is to obtain a structure that allows the light distribution ratio of the aperture to be obtained.

Composition of the Invention In order to achieve this object, the present invention adjusts the light distribution ratio within the cross-sectional area of the optical path passing through the slit opening provided in the slit plate, using a light distribution plate that responds to the position of a variable element according to the magnification. In a variable magnification exposure device of a copying machine, a shaft is held by a bracket and is provided along the longitudinal direction of the slit plate, and a shaft swings on the shaft in a direction perpendicular to the extending direction of the shaft. a light distribution plate that is divided into two plate-like members and arranged along the longitudinal direction of the slit opening; a member connecting the movable members, a spring member provided to bias the light distribution plate in opposite directions, and the shaft so as to engage with an engaging portion provided on the outer end side of each of the light distribution plates. The present invention proposes a variable magnification exposure device for a copying machine, comprising an engaging member provided above and an adjusting member for swinging the swinging member and adjusting the initial position of the light distribution plate with respect to the slit opening. It is.

Embodiments Hereinafter, details of embodiments of the present invention will be explained with reference to FIGS. 1 to 3.

FIG. 2 shows the entire variable magnification exposure apparatus according to the present invention, in which a pair of guide rods 2R and 2 are provided on the left and right sides of the exposure apparatus box 1, extending in a direction parallel to the optical axis X.
L has been constructed. These guide rods 2R, 2
A lens mounting plate 3 and a second mirror support member 4, which can be moved to a position in the optical axis direction according to a designated copying magnification, are mounted on L, and the light reflected from the original from the first mirror 5 is transferred to the second mirror. The second mirror 6 of the two-mirror support member 4, the in-mirror lens 7 of the lens mounting plate 3, and the third mirror located at the end of the exposure device box 1.
The light passes through the mirror 8 and is incident on and imaged on a photoreceptor (not shown). A light distribution adjustment device 10 whose details are shown in FIGS. 1 and 3 is located between the in-mirror lens 7 and the third mirror 8 along the optical axis X. The amount of light passing through the slit opening 11 is adjusted according to the copying magnification.

The light distribution adjusting device 10 whose details are shown in FIGS. 1 and 3 includes an "L"-shaped slit plate 12 and a "U"-shaped mounting bracket 13 that are separately attached to the bottom plate 1a of the exposure apparatus box 1. An elongated slit opening 11 is formed in the upper part of the slit plate 12 to limit the amount of light passing therethrough. The upper part of the mounting bracket 13 is connected to the swinging member 1 having a "U"-shaped cross section via a control rod 14 which is rotatable and extends in the left-right direction.
A pair of light distribution plates 17R, 17R are attached to the front wall 15a of the swinging member 15, which supports the slit plate 12 and is folded approximately vertically close to the slit plate 12, via fulcrum pins 16R, 16L.
17L is installed. These light distribution plates 17R,
17L is biased in opposite directions by a biasing spring 18 that is stretched between the respective ears 17a, 17a, so when no external force acts on the light distribution plates 17R, 17L, it retreats below the slit opening 11. . Further, on the bottom wall 15b of the swinging member 15, there is provided an adjustment screw 1 whose tip abuts against the bottom wall 13a of the mounting bracket 13.
9 is screwed in, and by adjusting an adjusting screw 19, the swinging member 15 can swing around the control rod 14. Therefore, by adjusting the adjusting screw 19, the initial height of the light distribution plates 17R, 17L relative to the slit opening 11 can be adjusted.

A driven lever 21 is fixed to one end of the control rod 14 and is driven by an actuating member 20 attached to the lower portion of one side of the lens mounting plate 3 described above, and is controlled as the lens mounting plate 3 moves according to a specified magnification. The rod 14 is made to rotate. The tip pins 22R, 22L of a pair of control levers 21R, 21L are fixed to the left and right sides of the control rod 14.
converts the rotation angle of the control rod 14 into a tilting angle of the light distribution plates 17R, 17L by engaging with driven pins 23R, 23L installed on the rear surface of the light distribution plates on the opposite side of the fulcrum pins 16R, 16L.

Since the illustrated embodiment has the above structure,
Even if there are processing errors or assembly errors in the constituent members, the light distribution adjusting device 10 can be adjusted later. That is, after attaching the slit plate 12 and the mounting bracket 13 to the exposure apparatus box 10, by simply adjusting the adjustment screw 19, the light distribution plate 17 can be adjusted to the slit opening 11.
Since the initial heights of R and 17L can be set, the amount of light passing through the slit opening 11 can be automatically adjusted according to the copying magnification using the light distribution plates 17R and 17L.

In the illustrated embodiment, an elongated rectangular light distribution plate is illustrated, but it is clear that the shape of the light distribution plate is selected according to the light distribution characteristics of the illumination lamp and the peripheral light amount characteristics of the lens.

Effects of the Device As is clear from the above explanation, according to the present invention, the relative position of the light distribution plate with respect to the slit opening can be adjusted after assembly, so even if there are processing errors or assembly errors in the component parts, it can be adjusted according to the copying magnification. It is possible to obtain a suitable light distribution ratio, which facilitates assembly and adjustment work.

[Brief explanation of the drawing]

Fig. 1 is an enlarged perspective view of the main parts of a variable magnification exposure device showing the features of the present invention, Fig. 2 is an overall perspective view of the variable magnification exposure device according to the present invention, and Fig. 3 is a sectional view of the device shown in Fig. 1. , FIG. 4 is a diagram illustrating the principle of a conventional variable magnification exposure apparatus. X...Optical axis, 11...Slit opening, 12...
Slit plate, 13...Mounting bracket, 14...
Control rod, 15... Swinging member, 17R, 17L
...Light distribution board.

Claims (1)

[Scope of utility model registration request] In a variable magnification exposure device of a copying machine that adjusts the light distribution ratio within the cross-sectional area of an optical path passing through a slit opening provided in a slit plate by a light distribution plate that responds to the position of a variable element according to the magnification, the exposure device is held by a bracket, a shaft provided along the longitudinal direction of the slit plate; a swinging member provided on the shaft so as to swing in a direction perpendicular to the extending direction of the shaft; and two plate-like members. A light distribution plate arranged along the longitudinal direction of the slit opening, a member connecting the inner end side of each of the light distribution plates to the swinging member, and a member that connects the light distribution plate in opposite directions. a spring member provided to bias the light distribution plate; an engagement member provided on the shaft to engage with an engagement portion provided on the outer end side of each of the light distribution plates; and the swinging member. rock it,
A variable magnification exposure device for a copying machine, comprising: an adjustment member for adjusting an initial position of the light distribution plate with respect to the slit opening.