JPH05341395A - Image exposing device - Google Patents

Abstract

PURPOSE:To miniaturize a lens part and also to reduce an error in light distribution on a photosensitive body. CONSTITUTION:As to the lens part L, 1st luminous flux control members 27 and 28 are constituted of at least one or more members, and the members 27 and 28 are provided with a luminous flux control shape 21 on the central part and also provided with supporting parts 31 and 32, 29 and 30 for supporting the supporting surface 23 which is installed separating from the lens part L on both end parts, the luminous flux is controlled by operating at least either of both end supporting parts 31 and 32, or the parts 29 and 30, that is, the parts 31 and 32, and the light quantity on the photosensitive body is controlled by the 1st and 2nd luminous flux control members.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image exposure apparatus for correcting uneven exposure, for example, in a slit exposure type variable-magnification copying machine or the like, in which unevenness of the light quantity distribution due to the cos 4 law of a lens or the like is eliminated. The present invention relates to an image exposure apparatus that corrects and provides uniform exposure in the slit longitudinal direction.

[0002]

2. Description of the Related Art Conventionally, in a slit exposure type variable magnification copying machine, when a slit area of an original is projected onto a photoconductor through a lens, the cos 4th power in the longitudinal direction of the slit corresponds to the angle of view of the lens. Exposure unevenness occurs due to the rule. In order to solve this, in a variable-magnification copying machine that uses a light source having a uniform luminance distribution, it is necessary to dispose a light flux regulating member that corrects the cos fourth law in the optical path.

For example, as an example thereof, JP-A-63-85
There is 730 publication. A schematic view of an embodiment of this image exposure apparatus is shown in FIGS. In FIG. 8 and FIG. 9, the cross-sectional area of the projected light flux from each object point in the slit area of the document is substantially the same regardless of the magnification change, that is, the lens 100.
In the vicinity of the optical path between the lens 100 and the photosensitive drum 101, which is a photoconductor, in order to correct the cos 4 power law of the lens, the light flux in the central portion of the slit region is regulated more than the light flux in the peripheral portion. Second light flux regulating members 102 and 1
03, the lens 100 and the second light flux restricting member 103 move integrally while maintaining the relative positional relationship during zooming, and the first light flux restricting member 102 disposed in the center of the lens 100 also There is one that corrects the exposure unevenness in each magnification range by moving according to the magnification change.

[0004]

In the above conventional example, as shown in FIG.
As shown in FIG. 9, the first light flux regulating member 102 is moved in the vertical direction corresponding to each magnification to uniformize the light amount distribution in the slit longitudinal direction on the photosensitive drum 101.
The movement of the first light flux regulating member 102 in the vertical direction is performed by a support surface on which a support portion of the first light flux regulating member 102 provided between the moving cams 120 of the two lens barrels 109 of the zoom lens is supported. Along the cam surface 105 of the first light flux regulating member 102, a projection 106 as a supporting portion provided on the lower surface side of the central portion of the first light flux regulating member 102 abuts, and both ends of the first light flux regulating member 102 are guided into guide grooves. Since the procedure is guided by 107 and 108, there are the following two drawbacks.

1. The moving cam surface 105 of the first light flux regulating member 102 has a cam 1 for moving the two lens barrels 109.
Since it is provided between the lens barrels 20, the space between the lens barrels 109 and 110 is limited, which is an obstacle to downsizing of the zoom lens.

2. When the protrusion 106 provided on the lower surface of the central portion of the first light flux regulating member 102 is pushed and moves up and down, both ends of the first light flux regulating member 102 and the guide groove 10 are moved.
A gap corresponding to the gap between the optical axis 7 and 108 is generated, and the light flux regulating shape 111 is inclined with respect to the optical axis.
An error is likely to occur in the light amount distribution on the photosensitive drum 101.

The present invention has been made in order to solve the above-mentioned problems of the prior art. The object of the present invention is to reduce the size of the lens portion and reduce the light amount distribution error on the photosensitive member. An object is to provide an image exposure apparatus.

[0008]

According to the present invention, there is provided a variable power image exposure apparatus for projecting an original image illuminated by a light source on a photoconductor through a lens at a predetermined magnification. A first light flux regulating member is provided in the lens portion, and a second light flux regulating member is arranged in front of or behind the lens, and the first light flux regulating member is composed of at least one member, and the member is a central portion. Has a light flux restricting shape and support portions for supporting the support surfaces provided at both ends apart from the lens portion, and regulates the light flux by operating at least one of the support portions at the both ends. The light flux regulating member regulates the amount of light on the photoconductor.

[0009]

In the image exposure apparatus having the above structure, the light flux is regulated by operating at least one of the supporting portions provided at both ends of the first light flux regulating member on the supporting surface to regulate the luminous flux. When the light flux regulating member regulates the amount of light on the photoconductor, the supporting surface is provided apart from the lens portion, and the supporting portion of the first light flux regulating member is also separated from the lens portion accordingly. The shape of the lens portion does not become an obstacle when the light flux regulating member 1 is activated. Therefore, the lens unit can be downsized.

Further, since the support portions of the first light flux regulating member are provided at both ends, there is less play during the operation of the first light flux regulating member, so that the light quantity distribution error on the photoconductor is reduced. be able to.

[0011]

1 to 4 show a first embodiment of the present invention, and FIG. 1 is a schematic sectional view of a variable magnification copying machine to which the image exposure apparatus of the present invention is applied. In the figure, 1 is an illumination light source for illuminating a document, 2 is a document table made of, for example, transparent glass, 3, 4, 5, 6, 7, and 8 are reflection mirrors, 9 is a projection lens which moves according to each magnification, 10 Is a photosensitive drum, which is a photoconductor, and the document placed on the document table 2 is illuminated by the illumination light source 1, and the slit regulating member 11 having a constant width moves the document image from the regulated slit area. The light is reflected by the reflection mirrors 3, 4, and 5, and the projection lens 9 and the first and second light flux restricting members 2 which are light flux diaphragm members.
The reflected light is reflected again by the fixed reflection mirrors 6, 7, and 8 via the light beams 7 and 12, and is projected on the photosensitive drum 10 with a different slit width corresponding to each set magnification. 2 is a detailed view of the image exposure apparatus of the present invention, FIG. 3 (a) is a sectional view taken along the line AA, FIG. 3 (b) is a state diagram of the operation of the image exposure apparatus, and FIG. It is a top view. Here, the lens portion L is configured such that 15, 16, 17 are movable lenses, 18 is a movable lens barrel holding the movable lenses, which are symmetrically arranged, 14 is a fixed lens, and 19 is a fixed lens 14. A fixed barrel that holds and guides the movable barrel 18. Reference numeral 26 is a collar, and 25 is a collar with a flange, both of which are screwed to the movable lens barrel 18. Reference numeral 24 denotes a cam plate having a cam shape 24A for guiding the collar 26.
It is held slidably in the direction of the arrow in (a). Reference numeral 33 is a guide member provided so as to project from the cam plate 24, and engages with a guide groove 34 provided in the optical frame body, and 35 is a fixed lens barrel 19
Guide groove 36 provided on the optical frame so as to project to the
Is engaged with. Here, the cam shape 24A and the guide groove 34 provided on the cam plate 24 are arranged such that the copy document image on the document table 2 surrounds the photosensitive drum 10 at each position where the fixed lens barrel 19 moves along the guide groove 36. It has a shape that moves the pair of movable lens barrels 18 so as to form an image on a surface. A driving wire 37 moves the fixed lens barrel 19 to obtain power from a driving source. Reference numerals 27 and 28 denote first light flux regulating members on which the light flux regulating shape 21 is formed.
One end of the fixed lens barrel 19 is provided as a support portion provided at both ends of the
A support surface rotatably held by shafts 29 and 30 provided at the other end, and projecting portions 31 and 32 as support portions are formed at the other end, and the projecting portions 31 and 32 provided at the cam plate 24 are supported. Is in contact with the guide surface 23. Reference numeral 12 denotes a second light flux restricting member disposed outside the fixed lens barrel 19, and a light flux restricting shape (not shown) is formed in the optical path portion. Drum 10
The light quantity distribution in the longitudinal direction of the upper slit is made uniform.

In the above structure, first, when the operation of the device is instructed by the operation input key (not shown), the drive source is operated by the command of the control circuit and the drive wire 3 is moved to the position of the instructed magnification.
At 7, the fixed lens barrel 19 moves along the guide groove 36. Due to the movement of the fixed lens barrel 19, the cam plate 24 moves in the fixed lens barrel 19 according to the shape of the guide groove 34. When the cam plate 24 moves, the movable lens barrel 18 guided by the cam shape 24A of the cam plate 24 also moves inside the fixed lens barrel 19. Also, the cam plate 2
A guide surface 23 is also provided on the surface 4, and the first light flux regulating members 27 and 28, one end of which is in contact with the guide surface 23 because the guide surface 23 also moves, are provided on the fixed lens barrel 19. It rotates about axes 29 and 30. First light flux regulating member 2
The light flux regulating shapes 21 formed on the reference numerals 7 and 28 are respectively shown in FIG.
It moves to the positions 38 and 39 shown in (b).

Accordingly, the fixed lens barrel 19 and the movable lens barrel 18 move at each of the designated magnifications, and the respective lens barrels 1 are moved.
Optical lenses 15, 16, 17, 1 held by 8, 19
An image of the copy document on the document table 2 is formed on the peripheral surface of the photosensitive drum 10 by the reference numeral 4. Further, by appropriately setting the shape of the guide surface 23 provided on the cam plate 24, the light flux regulating shapes 38, 39 and the second light flux regulating shapes 38, 39 formed by the movement of the first light flux regulating members 27, 28 at each magnification. With the shape provided on the light flux regulating member 12, the light flux in the slit area of the copy document on the document table 2 is made uniform on the peripheral surface of the photosensitive drum 10 in the slit longitudinal direction to prevent uneven exposure.

In this structure, the first light flux regulating members 27 and 28 are provided.
Guide surface 23 for moving the shafts 29, 30 holding the
Are located outside the movable lens barrel 18 which is the lens portion L and the driving cam shape 24A thereof.
In a small zoom lens system with 8 and 19 smaller,
These shapes do not become an obstacle, and a smaller zoom lens system can be manufactured. The light flux regulating shape 21 of the first light flux regulating members 27, 28 is located between the shafts 29, 30 and the protrusions 31, 32 in contact with the guide surface 23, and the light flux regulating shape 2
The movement of 1 is the value of the amount of change in the height direction of the guide surface 23 around the axes 29 and 30 x (distance from the axes 29 and 30 to the light flux regulating shape / interval between the axes 29 and 30 and the protrusions 31 and 32). Since it moves, since it moves about the axes 29 and 30, there is little backlash when moving, and the amount of movement is also the value reduced as described above with respect to the amount of change in the height direction of the guide surface 23. The height error of the guide surface 23 also has a reduced value. Therefore, the light flux regulating shape 21 can be moved with higher accuracy than ever before, so that the light quantity distribution on the photosensitive drum 10 can be made more uniform.

FIG. 5 is a sectional view of an essential part of an image exposure apparatus according to the second embodiment of the present invention, in which a rack is provided on the cam plate 24 as a supporting surface for supporting the supporting portions of the first light flux regulating members 45 and 46. Four
0 is provided, and the rack 40 meshes with a gear 41 rotatably mounted on the frame body of the fixed lens barrel 19. Gear 41
The gear 42 and the gear 42 mesh with the gear 43, and the gear 43 and the cam 44 are rotatably held by the frame body of the fixed lens barrel 19 so as to rotate in synchronization with each other. The gears 41, 42, 43 and the cam 44 are the first light flux regulating member 4
It is a support part of both ends of 5, and 46.

The first light flux restricting members 45 and 46 have a light flux restricting shape 21 and are pressed by elastic members (not shown) so that both ends thereof come into contact with the cam 44, and a guide portion 47 of the frame body of the fixed lens barrel 19. , 48. The cam plate 24 is shown in FIG.
Moving in the arrow direction, the gears 41, 42, 43 and the cam 44 also rotate in the arrow direction, and the first light flux regulating members 45, 4
6 and the light flux regulating shape 21 move to make the light flux distribution in the slit longitudinal direction on the photosensitive drum 10 uniform with the second light flux regulating member 12. Since other configurations and operations are the same as those of the first embodiment, the same reference numerals are given to the same components and the description thereof will be omitted.

FIG. 6 is a diagram of the third embodiment of the present invention, which is an example of a small apparatus in which the movement amount 1 of the light flux regulating shape 21 is small, that is, the magnification of zooming is small. This embodiment is an example in which only one of the first light flux regulating members 27 of the first embodiment is used.
Since the copying magnification that changes is small, the amount of change in the light amount distribution on the photosensitive drum 10 is also small. Therefore, the first light flux regulating member 27
Is small, and since m≈n, the light amount distribution can be made uniform. Since other configurations and operations are the same as those of the first embodiment, the same reference numerals are given to the same components and the description thereof will be omitted.

FIG. 7 is a diagram of a fourth embodiment of the present invention. The cam plate 24 is provided with guide surfaces 50 and 51 as supporting surfaces for supporting the supporting portion of the first light flux regulating member 56, and the first light flux is provided. The restricting member 56 is provided with guide portions 54 and 55 as support portions at both ends, and the protruding portion 52 and
53, the first light flux regulating shape 57 moves by the movement of the cam plate 24 and the light flux regulating shape arranged in front of or behind the fixed lens barrel 58 makes the light quantity distribution on the photoconductor uniform. Turn into As a result, the space in the height direction is the same as the conventional one, but since the vertical movement is performed by the cam surfaces at both ends, the light flux regulating shape is unlikely to tilt when moving up and down, and the guide surfaces 50, 51 are viewed in plan. The lens barrel portion can be shortened in the lens thickness direction. Since other configurations and operations are the same as those of the first embodiment, the same reference numerals are given to the same components and the description thereof will be omitted.

In each of these embodiments, the first light flux regulating member is moved by the movement of the cam plate.
The movement of the light flux regulating member may be obtained from another drive source such as a stepping motor.

[0020]

As described above, the first light flux regulating member is arranged in the lens portion and the second light flux regulating member is arranged in front of or behind the lens, and the first light flux regulating member is at least one member. The first light flux regulating member has a light flux regulating shape at the center and a supporting portion at both ends for supporting a supporting surface provided apart from the lens portion, and at least one of the supporting portions at both ends is actuated. The zoom lens system can be downsized by moving the member and making the light amount distribution on the photoconductor uniform in the range of each magnification by the first and second light flux regulating members, and the movement of the light flux regulating member. It is possible to reduce the light amount distribution error on the photoconductor with the improvement of the positional accuracy.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a variable-magnification copying machine to which an image exposure apparatus according to a first embodiment of the present invention is applied.

FIG. 2 is a detailed vertical sectional view of the image exposure apparatus of FIG.

3 (a) is a sectional view taken along the line AA of FIG. 2, and FIG. 3 (b) is a state diagram of the operation of the image exposure apparatus of FIG. 3 (a).

FIG. 4 is a partially cutaway plan view of FIG.

5 (a) is a longitudinal sectional view of an essential part of an image exposure apparatus according to a second embodiment of the present invention, and FIG. 5 (b) is a sectional view taken along line BB of FIG. 5 (a). Is.

FIG. 6 is a side sectional view of an image exposure apparatus according to a third embodiment of the present invention.

FIG. 7 is a side sectional view of an image exposure apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a schematic vertical sectional view of a variable-magnification copying machine to which a conventional image exposure apparatus is applied.

9 (a) is a vertical sectional view of the image exposure apparatus of FIG. 8, and FIG. 9 (b) is a sectional view taken along line CC of FIG. 9 (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Photosensitive drum (photoreceptor) 12 Second light flux regulating member 18 Moving lens barrel 19 Fixed lens barrel 21 Light flux regulating shape 23 Guide surface (supporting surface) 24 Cam plate 24A Cam shape 27 First light flux regulating member 28 First Luminous flux regulating member 29 Axis 30 Axis 31 Protruding portion (supporting portion) 32 Protruding portion (supporting portion) 40 Rack (supporting surface) 44 Cam 45 First luminous flux regulating member 46 First luminous flux regulating member 47 Guide portion 48 Guide portion 50 Guide surface (support surface) 51 Guide surface (support surface) 52 Projection portion (support portion) 53 Projection portion (support portion) 54 Guide portion 55 Guide portion 56 First light flux regulating member 57 Light flux regulating shape

Claims (1)

[Claims] 1. A variable-magnification image exposure apparatus for projecting an original image illuminated by a light source onto a photoconductor through a lens at a predetermined magnification, and a lens unit of the lens having a first light flux regulating member. A second light flux restricting member is disposed in front of or behind the lens, and the first light flux restricting member is composed of at least one member, and the member has a light flux restricting shape at a central portion and the lens at both ends. Has a supporting portion for supporting a supporting surface provided apart from the portion, and regulates the light flux by operating at least one of the supporting portions at the both ends, and the light amount on the photoconductor with the second light flux regulating member. The image exposure apparatus is characterized in that it regulates.