JPS5915237A - Optical device of microcopying machine - Google Patents

Abstract

PURPOSE:To obtain different magnification by use of one lens and without changing a distance between a lens and a microfilm, and also to obtain a correct copy even if the magnification is changed greatly, by inserting selectively a parallel plate having high optical transmissivity between a film and a main lens in accordance with the magnification, and also moving and adjusting a position of the film in the direction orthogonal to the optical axis in accordance with the magnification. CONSTITUTION:A distance between a microfilm 8 and a main lens 5 is corrected by setting and fixing a distance L between the microfilm 8 and the main lens 5 to the shortest distance in the variable necessary magnification, and inserting a parallel plate 9 having high optical transmissivity between the microfilm 8 and the main lens 5 in accordance with a variation of magnification, so that a copy whose magnification is different can be obtained correctly without adjusting the distance L between the microfilm 8 and the main lens 5. Also, a film placing plate is made freely movable in the direction orthogonal to the optical axis, and is subjected to fine control by a pulse motor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical device in a microcopying machine for making copies from microfilm, and more particularly to an optical device that allows a plurality of different magnifications to be obtained.

Conventionally, in the optical device of a microcopying machine, when attempting to obtain true multiple magnifications, lenses with different magnifications were prepared and replaced sequentially in a turret style, and a device was used to create a gap between one lens and the microfilm. What is needed is an apparatus that is capable of finely adjusting the distance between the two images as the magnification changes, and is equipped with a mirror system that allows the common yoke length to be made variable.

However, the former device requires a large number of lenses and is expensive, while the latter device requires a fine adjustment function to accurately match the back focus of the lens and has a complicated structure. This method has the drawbacks of being complicated and costly.

The present invention was made in view of the above circumstances.The main purpose of the present invention is to use f lenses to obtain different magnifications without changing the distance between the lens and the microfilm, and to be able to obtain the correct magnification even if the magnification is greatly changed. An object of the present invention is to provide an optical device for a microcopying machine that allows copies to be obtained.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall view of a microcopying machine, in which a light source 2 and a condenser lens 3 are provided on the upper part of the main body 1, and below a film mounting table 4 there is a main lens 5, a group of mirrors 6, and a drum 7.
is provided to expose the image of the microfilm 8 on the film mounting table 4 onto the drum 7 to obtain a copy.
are doing.

The optical device is schematically shown in FIG. 2, in which a group of mirrors 6 is movable. 2nd and 3rd mirror combinations 6+, 62.6g and a fixed mirror 64, depending on the magnification, either mirror combination 6+, 62.6g
This is done so that it coincides with the k optical axis.

In the optical device shown in FIG. 2, if a magnification MOLD copy can be made, the light from the light source 2 is condensed by the condenser lens 3, and the image portion of the microfilm g is transmitted through the main lens 5 to one of the mirror combinations 61. Then, it is reflected by the fixed mirror 64 and transmitted onto the drum 7 as an image multiplied by Mo.

Then, Mo times the image is copied onto paper in a conventionally known manner to obtain Mo times the number of copies.

In addition, when trying to obtain a copy with magnification ML using the optical device Δ shown in FIG. . However, fVi is the focal length of the main lens 5.

Therefore, an auxiliary glass qf!, which serves as a parallel plate with high light transmittance, is placed between the microfilm 8 and the main lens 5! : The same result could be obtained by inserting the microfilm 8 at right angles to the optical axis and finely adjusting the distance LiΔL between the microfilm 8 and the main lens 5.

In other words, if the thickness of the auxiliary glass 9 is ti1 and the refractive index is L4 (L1NI), then the distance has changed by the value shown by the following equation by inserting the auxiliary glass 9.

δ1-(nil)ti Therefore, the thickness and refractive index of the auxiliary glass 9 are
! ---"-) Mo so that the value of f and δt match
M! By selecting , it is possible to obtain a copy of the multiplication factor without moving the main lens 5.

To summarize above, the distance between the microfilm S and the main lens 5 is N#L *The closest distance among the variable magnifications 1
11 parallel plate with light transmittance of ps, tt1, refractive index, rLL, with the setting fixed at ef and changing magnification. '& δi-(
Elbow-1) The distance between the microfilm 8 and the main lens 5 is fully corrected by the distance tt, and the distance between the microfilm 8 and the main lens 5 is
It is now possible to correctly obtain copies with different magnifications without having to adjust the distance.

This eliminates the need for a complicated mechanism such as moving the main lens 5, resulting in high costs. , θ.

However, in this case, if the difference between Mo and Mi is increased (change in magnification is large), the correction amount δ by the correction glass 9
Since t is a dog, the correction glass 9 is
The completely transmitted light is deviated from the optical axis due to the refraction of the light, and is no longer transmitted to the drum 70P9 [at its normal position.

Therefore, the film mounting table 4 is made movable in the direction perpendicular to the optical axis, and a pulse motor 10 is used to control the irradiance by minute IR+1.
The above-mentioned deviation of the optical axis is corrected by moving the light by a distance Δ'L corresponding to the refractive index of i1, ni, so that the light always passes through the drum 7 at a predetermined position.

In other words, the position of the microfilm 8 when the magnification is hio (
When setting the magnification to M1 with respect to the scan start position), the auxiliary glass 9 is inserted to deviate from the optical axis by Δ'L.

Therefore, the thickness tL of the inserted auxiliary glass 9.

Calculate Δ'L ffi according to the above-mentioned formula according to the refractive index rLi, and correct the position of the microfilm 8 by sending a drive signal to the pulse motor 10 to move the bamboo film mounting table 4 based on this Δ'■. .

The auxiliary glasses 9 may have different thicknesses as shown in Fig. 2 and may be moved in the direction of the arrow as a whole, or multiple auxiliary glasses 9 with different thicknesses or refractive indexes may be moved in a turret type according to the magnification. You may also insert it into

The present invention is as described above, and it is possible to obtain copies with different magnifications without adjusting the distance between the film 6 and the main lens 5. The optical system of the copying machine is F+','.

The position of the film 8 can be shifted in the direction perpendicular to the optical axis as the magnification is doubled, making it possible to adjust the optical axis by adjusting the position of the film 8. , Drano can always be transparent to a predetermined position on the top, so the correct copy is inserted.

[Brief explanation of drawings]

FIG. 1 is an overall view showing an embodiment of the present invention, and FIG. 2 is a schematic explanatory view of an optical device. 5 is the main lens, 8 is the film, and 9 is the parallel plate. Applicant Fuji Xeronx Co., Ltd. Agent Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto

Claims (1)

[Claims] In a microcopying machine that obtains copies at multiple magnifications using a single lens, a parallel plate 9 with high light transmittance is selectively inserted between the h-ilm 8 and the main lens 5 according to the magnification, and the position of the film 8 is adjusted according to the magnification. An optical device for a microcopying machine, characterized in that the optical device can be adjusted to move in a direction perpendicular to the optical axis according to the optical axis.