JPS6070429A - Light quantity distribution correcting device of slit exposure type copying machine - Google Patents

Abstract

PURPOSE:To make a light quantity distribution constant on the image forming surface of a copying machine exposing system, no matter how a copying magnification is varied, by rotating a cylindrical slit member in accordance with variation of the copying magnification, forming a sectional shape of a slit-like optical path in the shape of a drum, and varying it. CONSTITUTION:When an exposing system is set to a necessary copying magnification by a copying magnification setting mechanism, the second and the third mirrors 7, 8 and a lens 10 are moved to a prescribed position, also by interlocking with it, a cylindrical slit member 15 is driven to rotate suitably, becomes a constant value by the width of an image forming side slit formed by its bus 18 and a u-shaped slit member inside edge 20, a light quantity distribution immediately before an image forming side slit part 14, and a light quantity distribution in case when the product has passed through the image forming side slit part 14, and becomes constant irrespective of a distance to a lens optical axis on the image forming surface and a copying magnification M. In this way, light can be irradiated uniformly to the surface of a photosensitive body which is an image forming surface of the exposing system, and a copy of good quality can be obtained.

Description

[Detailed Description of the Invention] Uninventively, Heslit et al. has proposed an element that can make the light intensity distribution constant on the imaging surface (photoreceptor surface) of the IaN light type in the prototype copying magnification type photocopying method. This is part F) regarding the 凛distribution correction device.

In the exposure system of the conventional technology, an 11-lit exposure type compound variable magnification machine,
As shown in FIG. 1, the angle of view θ of the lens at which the principal axis , i.e., the lens position M (changes for each mutual magnification, e.g., equal magnification), the lens position M, and the original axis L
The angle of view of the lens θ1 and S
The angle of view θ2 of the lens formed by the line x2 is different from the original axis LvC vs. f at the lens position @M2 at 50% magnification.

Then, in the tile-like n body surface A, V and Kti, the image is B plane and σ) which is flat r〒, :M, axis L [inclined by θ to the original axis, and When illuminating the imaging plane B parallel to a 1σ angle surface, the illuminance distribution on the imaging plane B is given by N cos
This development Y COS 4θ decreases in proportion to the fourth power of θ.
Since the conjugate image of the object point C on the image plane B changes depending on the magnification, the lr1 degree distribution on the image plane B changes in accordance with the magnification.

Furthermore, in order to obtain a homogeneous copy, it is preferable that the elemental quantity distribution on the imaging plane B be constant, so conventionally, the light intensity distribution on the imaging plane at a specific magnification (σ)? The light source is formed so that the light intensity distribution on the object surface A is low at the center and becomes higher as it approaches the rain gap, and Yf is such that the width of the exposure slit on the object side or the imaging side is at the center. The exposure slit was formed in the shape of a 7-r to 5-Vc drum, which was narrow and widened as it approached both ends.

However, with such scene distribution correction means, tx s
% Although the exposure amount is corrected at a fixed magnification, the exposure amount cannot be corrected at other magnifications.

In order to improve this, the imaging plane B is
There was a device that prepared several drum-shaped exposure slits to maintain a constant illuminance distribution, and arranged them in the selective VC optical path to correspond to the alternating magnification. The magnification can be changed many times in small increments, or an anchor camera is required that can continuously change the magnification. It was difficult or impossible to keep it constant.

OBJECT OF THE INVENTION The present invention relates to an improvement of a slit exposure type copying machine σ)'i quantity distribution correction device that overcomes these difficulties. A simple light quantity distribution correcting device having a structure that maintains a constant light quantity distribution on the image forming surface of a hard-pressure exposure system is needed.

Structure of the Invention In the present invention, in the exposure thread of the one-slit exposure type variable magnification variable Nisakura Alternate Iso, it is possible to cope with changes in the slit-like original path and the magnification σ parallel to the imaging plane of the exposure system. Then, at least one cylindrical slit part σ) is rotatably supported by the VC, and at the same time, from [the cylindrical slit part θ's 1lq11 direction center) t] to both sides ``tW VC smoothly curves in the direction facing toward Ffl and approaches its rotation center VC, and the same cylindrical slit part Ji and other linear slit members or the same cylindrical slit part side,
This is achieved by forming the cross-sectional shape of the slit-shaped source path into a drum-like shape so that the exposure system image formation (σ) uniformly distributes the element amount.

However, in the present invention, the generatrix of the slit-shaped material is moved closer to its center of rotation in response to the increase in the re-H magnification VC.
By forming a VCW that is independent of changes in reproduction magnification,
It is possible to set the original image plane to a constant value.

EXAMPLE Below, an example of the present invention will be explained.Before explaining how the light intensity distribution of the iC% exposure system on the imaging plane changes in response to changes in the close-up magnification, please refer to Fig. 2. The state will be explained optically.

The focal length of the 5 Let f be the imaging magnification, M1, and the lens field angle θ, which is centered on the principal ray P from the object point C.

Then, the lens N is placed at a location a distance away from the object plane A, and the imaging plane EICi is located away from the lens N by a distance b.
... River - (1), and the relationship between the magnification M and α, b is M-
(2) From the above formula (L) (2), α, b difference Nσ
) Focal length f and yB magnification M are shown as 1-K, and Figure 2 clearly shows '1K.

A=(1+M)f (4).

Also, if σ) light intensity distribution on object surface A is F (X) ~ Enoki's alternating magnification is M times and σ) light intensity distribution on image-forming surface B is GM (2'), then σ) light intensity on image-forming surface B Distribution G1. + (χ) is expressed by the following formula % formula % Now, when using a light source with a constant light intensity distribution F (X) on the subject surface A, the result when setting an arbitrary σ] a)'S rate MVc exposure Light intensity distribution on image plane B G1.1(r)&
'f-1.

To explain this specifically, f = 200 mrn-
,' M = 11 The maximum distance from the lens axis on the object plane A is X max = 160 mm, and the maximum distance xmαX from the lens axis on the imaging plane B is 160'
In the case of binding that cannot exceed mm, as shown in Fig. 3, in the light intensity distribution G+('') on the imaging plane B, the light figs decreases as X increases from equation (6). ,X r
At nax-x rnax=16Q y,z, the light amount drops to 0.743.

On the other hand, M==Q, 9.0.8.0.7 field a has a large distance −r of 1 degree from the lens original axis on the imaging plane B.
7nQ, :C are respectively 144mm5 128mm5
112 mm ~ As shown in FIG. 3 VC, the light amount distribution G on the imaging plane B 6. el (x), Ga, s+
G”), G, , 7(x), the light amount decreases as X increases according to equation (6), and specifically, the light amount of 1.r==Q is 1.111.1. 25.1.429 was,
x max = L441nR% 128 m'rl,
The amount of light at LL2mmlC is 0,850.0.935
．． 1.163, and the proportion of the light intensity decrease σ) becomes more significant as the breaking magnification decreases.
In the case of imaging 1.5, as illustrated in FIG. f
Light intensity distribution on IliB G1,1←), G7. ．． 2 (
ri, G/, 3 Cx), G/, vh), a 1-s-
From equation (6), Xθ) is increased by 7 JOv.
Specifically, when the radiation of x = Q becomes 0.
909.0.833.0.769.0, 714.0.6
6Tc σ), x max = 160 mm
VC holder/-) light intensity (technical (1693, 0, 650, 0,
It decreases to 612, 0,579, 0,549 - the rate of decrease in light intensity becomes more gradual as the Enoki mushroom magnification gets older.

According to the embodiments shown in FIGS. 4 to 7, the light intensity distribution F CX) on the subject plane A is constant.
Let's explain the case where the light quantity distribution H1, I(2') on the n-th imaging plane B is constant.

① is a slit exposure type dry type electronic retrieval machine. 1. A glass plate placed above it moves left and right at a speed corresponding to the magnification. .

In addition, a platen cover 3 is mounted on the top surface of the platen glass 2 so that it can be opened and closed vertically, and a document 4 with a maximum diameter of 2 A = 320 m is placed on the platen glass 2. Natsu is here.

Furthermore, a linear exposure lamp 5 such as a linear halogen lamp 'f' or a fluorescent light whose luminous intensity distribution in the longitudinal direction is uniform is disposed below the platen glass 2, and the exposure lamp 5 projects light onto the platen glass. 2 upper σ) One light diffusely reflected by the original 4 is reflected by the 11th second and third mirrors 6, . The light is sequentially reflected at 7.8, passes through the lens 10, is reflected at the fourth mirror 9, and is then irradiated onto the drum-shaped sensing element 11.

Therefore, the focal length of the lens 10 is fixed and is 200 mm, and the lens 10 and the second and third mirrors 7-%8 have a viewing magnification M set and INl, and the above (1) (2)
The movement of the IcS is adjusted by a copying magnification setting mechanism (not shown).

Further, a subject-side plate-shaped slit member 13 having a constant slit width is disposed above the first mirror 6, so that the original light quantity narrowed by the plate-shaped slit member 13 is uniformly distributed.

Further, the fourth mirror 9 and the exposure area 12 of the drum-shaped photoreceptor 11
Between the image forming side slit A14 and the same image forming side 1
■The slin I part 14 consists of a cylindrical slit member 15 and a U-shaped slit member 19, and the cylindrical slit part side 1
5 is the same F-shaped surizo) +? (The cylindrical slint material 15 is rotatably supported parallel to the shaft 19 and centered on the center line 17, and the cylindrical slint material 15 is shown through the transmission thread 23 and the drive shaft 2/l, which are made of a bully 21 and a belt 22. [22,
5 degrees) It will be driven by IC rotation.

But the cylindrical slit L? In 150m line 18 (
Rotation center line] 7' If (Cut the cylindrical Nullite material I5 on the plane, and cut the circumferential surface 2'
The slit width W of the imaging side slit section 14 in the set and rotated state is In addition, W. is the coefficient.

In a satisfactory manner, the cylindrical slit member 15 is formed and pivoted to the U-shaped slit member 19 at a predetermined 0°C position.

The shape of the generatrix 18 of the cylindrical slit member 15 cut along the cross section shown in FIG. 6 is as shown in FIG. 7.

Note that the outer circumference VC of the drum-shaped photoreceptor 11 corresponds to the exposure area 1.
From 2 onwards, developing, transferring, peeling, cleaning, and charging equipment are sequentially arranged, and these equipments are used to carry out normal dry type electrophotographic copying.

Since the embodiments shown in FIGS. 4 to 7 are constructed as described above, they can achieve the following effects.

When the exposure system is set to the required magnification by the recursion magnification setting mechanism, the second and third mirrors 7.8 and the lens 10 are moved to predetermined positions, and in conjunction with this, the cylindrical The slit member 15 is rotated as appropriate, and its generatrix I8
Since the width W of the imaging side slit formed by the addition of the inner edge of the F-shaped slit 141S satisfies equation (7), -yt and the amount distribution aF- just before the imaging side slit 14. 1Cv)
Even if the distribution is distorted as shown in equation (6), when it passes through the 1% imaging side slit FM14Y, the light amount distribution H
N-) is the product of equations (6) and (7), =KW.

Therefore, on the imaging plane B, σ) about the lens original axis and σ) are constant regardless of the distance X and the yg magnification M.

In this way, in the above embodiment, the light amount distribution in the exposure area 12 of the photoreceptor 11 is determined regardless of the change in the image magnification M)]M←
) can be maintained constant, and it is possible to obtain stable, high quality and thick materials.

In the embodiment described above, the light emission amount distribution along the longitudinal direction of the linear exposure lamp 5 is 7-uniform, and the plate-shaped slit member 1 on the subject side
By setting the width of the slit 3 to be constant, the light intensity distribution F on one subject plane A, that is, the surface of the original 4) is set to a constant IC, or the light intensity at the center of the original 40 [1] direction is weak and close to both sides of the original. If the light intensity distribution F←) is such that the light intensity is strongly distributed, then change formula (7) to f%14Y so that it conforms to formula (8). good.

However, even if the same cylindrical slit member 15 is formed with two non-parallel cylindrical slit members 15 so as to conform to the image formation width E (7) or (8), the same result can be obtained. It can be effective.

Further, the circumferential surface lG of the cylindrical slit member 15 is formed into a cubic curved surface that curves smoothly both in the circumferential direction and in the axial direction. The cylindrical slit member 15 is formed on the tied quadratic curved surface.
Alternatively, the cylindrical slit member 15 may be formed in such a shape that only the mother fitting 118 is protruded and the adjacent portion is depressed.

Effects of the Invention In the present invention, by rotating the cylindrical slit member in accordance with the copying magnification, the slit shape is appropriately apertured on the side of the cylindrical slit portion, and the image forming surface of the exposure system is formed. ! ! - It is possible to uniformly irradiate the surface of the light body and obtain high-quality copies.

Further, in the present invention, even if the image magnification of the exposure system is continuously changed, the cylindrical slit member can be continuously rotated in accordance with this change, and the cross-sectional shape of the slit can be continuously changed. With σ), the amount of light irradiated by the VC on the photoreceptor surface can be evenly distributed at any binaural magnification.

Furthermore, in the present invention, the cross-sectional shape of the slit can be continuously changed simply by rotating the cylindrical slit member 7 simultaneously, so that the slit portion IA of the multi-shio
Not only does it not require any trouble, but it also eliminates the need for replacement means, has fewer parts, is easier to draw, has fewer breakdowns, and is highly reliable.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram that explains how the lens angle of view θ changes in response to changes in the reversing magnification, Figure 2 is an explanatory diagram that illustrates the lens formula, and Figure 3 is the light intensity distribution on the subject plane. Characteristics of the light intensity distribution on the imaging plane when a constant light source is used and the exposure system is set to an arbitrary magnification M. Fig. 4 shows an embodiment of the light intensity distribution correction device according to the invention. 5 is an enlarged perspective view of its main parts, and FIG. 6 is a side view of the same. 1. FIG. FIG. 3 is a cross-sectional view of a shaped slit member. DESCRIPTION OF SYMBOLS 1...Slit exposure type dry type electrophotographic copying machine, 2...Platen glass, 3...Flatten cover, 4...Original height, 5...Linear exposure rung, 6...No. 1? Ra,
7...Second? 5% 8”'3rd mirror, 9...
4th mirror, 10... Lens to 11... Drum-shaped sensing element, 12... N-yf: area, 13... Body surface side plate-like slit section side, 14... Imaging side slit evil s 15
... Cylindrical slit member, 16... Cylindrical slit member circumferential surface, 17... Cylindrical slint member rotation center line, 18.
... Cylindrical slit member generatrix, 19... U-shaped slit member, 20゛°, U-shaped slit member + J) inner edge of throat member, 21
...7-11, '22...Belt, 23...
・Transmission system, 24... Drive surplus 1゜ Agent: Patent attorney Nozomi Ehara, 71-year-old brother

Claims (1)

[Claims] In the exposure system of a slit exposure type variable magnification type camera, at least one element is rotated about an axis χ parallel to the slit-like original path and the exposure system image forming plane in response to changes in yg magnification. The mother edge of the cylindrical slit member is provided with a smooth v in the direction from the center in the axial direction of the cylindrical slit member toward the 9th part and toward the center of rotation of the cylindrical slit member.
A light amount distribution correction device for a slit-exposure type Buddha, characterized in that the cylindrical slit member is formed in such a manner that it bends and approaches its center of rotation in response to an increase in S compound magnification.