JPH07191413A - Optical device - Google Patents

Abstract

PURPOSE:To provide an optical device suited to an image forming mechanism constituted by considering the miniaturization of a copying machine and the effective utilization of a space inside the copying machine. CONSTITUTION:A second reflecting mirror 7 is arranged on the right side of a lens 8 and a third reflecting mirror 9 is arranged on the left side of the lens 8. Besides, a fourth reflecting mirror 10 is arranged under the mirror 9. Thus, the space at the upper part or on the left side of a fixing device 21 and a paper ejection means positioned on the upper side of a photoreceptor drum 11 is effectively utilized. Besides, the height and the length of an optical system is set to be nearly the same as that of the optical system of a conventional copying machine without making the focal distance of the lens long. At a variable power time, the distance between the lens 8 and the drum 11 is adjusted by moving the fourth reflecting means 10 constituted of two mirrors in the center axis direction of an angle (theta).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device relating to the arrangement of a reflecting mirror and a change in magnification of an exposure optical system in a copying machine or the like.

[0002]

2. Description of the Related Art An example of a conventional arrangement of a reflecting mirror of an exposure optical system of a copying machine and an optical device relating to a change in magnification will be described with reference to the drawings.

FIG. 3 shows an exposure optical system of a conventional copying machine. In FIG. 3, a platen glass 1 on which a document is placed
The first scanning section is composed of the lamp 102 and the first reflecting mirror 103 which move under 01 to scan the original, and the second scanning section which moves at a speed ratio of 1/2 of that of the first scanning section. Is composed of the second reflecting mirror 104. The light flux from the document scanned by the first reflecting mirror 103 and the second reflecting mirror 104 passes through the lens 105, is reflected by the third reflecting mirror 106 and the fourth reflecting mirror 107, and reaches the photoconductor drum 108.

The positional relationship from the irradiation surface of the light beam to the photosensitive drum 108 to the center of the lens 105 in the above configuration will be described. The lens focal length is f, the distance from the center of the lens 105 to the center of the light flux at the third reflecting mirror 106 is a, the distance between the two reflecting mirrors of the third reflecting mirror 106 is b, the third
When the distance from the reflecting mirror 106 to the fourth reflecting mirror 107 is c, the distance from the fourth reflecting mirror 107 to the photosensitive drum irradiation surface is d, and the reflection angle to the photosensitive drum is α with respect to the horizontal plane, 2f = a + b + c + d And the distance e from the irradiation surface of the photosensitive drum to the lens center is e = a- (c + d cos α). With the arrangement of the reflecting mirror of the exposure optical system configured as described above, the following operation will be described.

As a normal means for changing the magnification to make a copy, the lens 105 is moved in the optical axis direction to change the distance from the original to the lens, and the lens 10 is used.
In order to match the distance from 5 to the photosensitive drum 8, the third reflecting mirror 106 is moved in the optical axis direction passing through the lens 105. Explaining the operation of the magnifying power, the lens 105 is moved in the arrow L direction and the third reflecting mirror 106 is moved in the arrow R direction.

[0006]

The position of the photosensitive drum in the image forming mechanism of the conventional copying machine is located substantially at the center of the image forming mechanism. The configuration of the exposure optical system for irradiating the photoconductor drum with light in this image forming mechanism and the distance e from the photoconductor drum irradiation surface to the lens center are as described above. The light flux from the reflecting mirror 107 to the photoconductor drum 108 needs to have an angle α with respect to the horizontal plane of the photoconductor drum 108. Unless 180 °>α> 0 °, the fourth reflecting mirror 107 moves to the photoconductor drum 108. The reflection of is impossible.

In the image forming mechanism in consideration of downsizing of the copying machine and effective use of the space used in the copying machine, the position of the photosensitive drum is located on the left side of the image forming mechanism. Since the device and the photoconductor drum are located above the photosensitive drum, the fixing device and the paper discharge device obstruct the exposure optical system. If the conventional exposure optical system is set on the fixing device and the paper discharge device, the lens 10
The distance from 5 to the photosensitive drum irradiation surface in the vertical direction of the photosensitive drum increases, and the distance b between the two reflecting mirrors of the third reflecting mirror 106 has to be long. However, there is a problem that the exposure optical system has a height of 1.

Further, if the conventional exposure optical system is set on the right side of the fixing device and the paper discharging device and the second reflecting mirror 104 is arranged on the right side of the fixing device and the paper discharging device, the length is longer than the conventional one. There is a problem in that it becomes a copying machine having a. At this time, the distance e from the photosensitive drum irradiation surface to the lens center
Requires a distance approximately equal to the moving distance of the second reflecting mirror 104. In order to make the distance longer than the distance from the irradiation surface of the photoconductor drum to the center of the lens, the distance from the lens 105 to the third
The distance to the reflecting mirror 106 is set to a, the distance between the two reflecting mirrors of the third reflecting mirror 106 is set to b, and the irradiation angle α to the photosensitive drum is set to be small so that the third reflecting mirror 106 to the fourth reflecting mirror 107 The distance c and the distance d × cos α from the fourth reflecting mirror 107 to the photosensitive drum irradiation surface must be long. The moving distance of the lens 105 and the third reflecting mirror 106 when changing the magnification.
In consideration of the moving distance of the lens 105, setting the distance a from the lens 105 to the third reflecting mirror 106 and the distance c from the third reflecting mirror 106 to the fourth reflecting mirror 107 to be short limits the range of magnification change. Therefore, there arises a problem that the distance e from the irradiation surface of the photosensitive drum to the center of the lens cannot be equal to the moving distance of the second reflecting mirror 104.

Further, the angle of the irradiation light to the photoconductor drum in the image forming mechanism in consideration of the downsizing of the copier and the effective use of the space for use of the copier is set on the horizontal plane of the photoconductor drum due to the construction of the developing device. Irradiation from -90 ° to 90 ° is required. The best irradiation angle is ± 0 ° with respect to the horizontal plane of the photosensitive drum. Conventionally, there is a problem that the arrangement of the reflecting mirror of the exposure optical system of the copying machine and the configuration of the magnification changing device cannot meet this condition.

In view of the above problems, the present invention provides an optical device suitable for an image forming mechanism in consideration of downsizing of a copying machine and effective utilization of space used by the copying machine.

[0011]

In order to solve the above problems, the arrangement of the exposure optical system of the present invention is such that the first reflecting means for scanning the original image and the incident light from the first reflecting means are reflected. A second reflecting means, a third reflecting means for reflecting the incident light from the second emitting means through a lens, and a fourth reflecting means for reflecting the incident light from the third emitting means to irradiate the photosensitive drum.
Reflecting means is provided, and the reflecting means are arranged so that the incident optical axis irradiating the photosensitive drum intersects with the incident optical axis incident through the lens. The reflecting mirrors are arranged such that the angle θ of the reflecting mirrors is 45 ° ≦ θ ≦ 90 °, and the angle β of the irradiation light to the photosensitive drum is −90 ° <β ≦ 60 ° with respect to the horizontal plane of the photosensitive drum. Irradiation is performed within the range. Further, as a means for adjusting the distance between the lens and the surface of the photosensitive drum at the time of zooming, the fourth reflecting means is arranged so as to be movable in the central axis direction of the angle θ.

[0012]

According to the present invention, with the above-described structure, the photosensitive member is arranged in the left side of the image forming mechanism in consideration of downsizing of the copying machine and effective use of the space used by the copying machine. By effectively using the space above and on the left side of the fixing device and paper ejection device located on the upper side of the drum,
Without increasing the lens focal length, the height of the exposure optical system and the range of length variation are set to those of the exposure optical system of a conventional copying machine. Furthermore, due to the construction of the developing device, For a developing device that requires an irradiation angle β from the direction of 90 ° to 90 °, it includes an irradiation angle of ± 0 ° with respect to the horizontal plane of the photosensitive drum, which is the best irradiation angle.
By enabling irradiation in the range of 0 ° <β ≦ 60 °, it is possible to provide an exposure optical system suitable for an image forming mechanism in consideration of downsizing of a copying machine and effective utilization of space used by the copying machine.

[0013]

EXAMPLE An optical device according to an example of the present invention will be described below.
A description will be given with reference to the drawings. FIG. 1 shows a copying machine having a configuration according to the present invention, which includes an exposure optical system 1 and an image forming mechanism 2 that forms an image by exposure by the exposure optical system 1.
The image forming mechanism 2 includes a paper feeding mechanism 3 that feeds the paper. These exposure optical system 1, image forming mechanism 2, paper feeding mechanism 3
May be formed integrally or separately. In particular, the paper feed mechanism 3 has a configuration in which a plurality of separate paper feed units 3a are stacked for each paper size.

The exposure optical system 1 has a first scanning section composed of a lamp 5 and a first reflecting mirror 6 which move under the platen glass 4 to scan an original, and the first scanning section is 1 / The second reflecting mirror 7 that moves at a speed ratio of 2, the lens 8 that moves to keep the optical path length constant, the third reflecting mirror 9, and the fourth reflecting mirror 10.
Is equipped with.

The image forming mechanism 2 includes a photosensitive drum 11, a charging means 12 arranged around the photosensitive drum 11, a side erase 13,
It has a developing unit 14, a transfer unit 15, a cleaning unit 16, etc., and forms a toner image corresponding to an optical image of an original image formed on the photosensitive drum 11 by exposure by a general electrophotographic method, and is fed. Transfer it to the incoming paper. In front of the transfer section where the photoconductor drum 11 and the transfer means 15 face each other, the paper feed roller 17 of the paper feed mechanism 3 and the separation roller 18 align the leading ends of the papers 19 fed one by one, and the timing of feeding Pair of registration rollers 2 for adjusting
0 is set. Further, behind the transfer unit, there are provided a fixing device 21 for fixing the transferred paper and a pair of discharge rollers 22 for discharging the paper sent from the fixing device 21.

Still, these paper transport systems have a unit mechanism that can be opened and closed with the paper transport system as a boundary so that paper jam processing can be performed easily.

The paper feeding mechanism 3 is provided with papers 19 of different sizes.
And a paper feeding unit including a paper path 24. The paper feeding units are stacked for each paper size to enable paper feeding corresponding to a plurality of paper sizes.

Numeral 25 is a tray for manual paper feeding.
Reference numeral 6 denotes a paper discharge tray. FIG. 2 shows the arrangement of the reflecting mirror of the exposure optical system and the mechanism for changing the magnification in the embodiment of the present invention. In FIG. 2, a platen glass 4 on which a document is placed
The first scanning unit composed of the lamp 5 and the first reflecting mirror 6 that move below to scan the document and the first scanning unit are 1
Second reflecting mirror 7 that moves at a speed ratio of / 2
The scanning section of the third reflection unit is arranged on the right side of the lens 8 and the light flux from the document scanned by the first reflecting mirror 6 and the second reflecting mirror 7 passes through the lens 8 and is then arranged on the left side of the lens 8. The light is reflected by the fourth reflecting mirror 10 arranged below the mirror 9 and the third reflecting mirror 9, and reaches the surface of the photosensitive drum 11.

The fourth reflecting mirror 10 is composed of two reflecting mirrors 30 and 31 which reflect the light from the third reflecting mirror 9. The angle formed by the extension lines of the reflecting surfaces of the reflecting mirror 30 and the reflecting mirror 31 is θ, and the optical axis from the third reflecting mirror 9 to the reflecting mirror 30 and the reflecting mirror 31.
At the point where the optical axis from the
The arrangement of the third reflecting mirror 10 and the reflecting mirrors 30 and 31 constituting the fourth reflecting mirror is set so that the bisectors pass through.

The angle range of the angle γ formed by the optical axis from the lens 8 and the reflecting surface of the third reflecting mirror 9 will be described.
When γ is smaller than 45 °, the optical axis from the third reflecting mirror 9 to the fourth reflecting mirror 10 faces the drum side, and the developing device 14 and the fourth reflecting mirror 10 in FIG. There is. Further, if γ is larger than 75 °, the optical axis may come into contact with the lens 8, and in order to avoid it, the focal length must be long, and the exposure optical system becomes large. Angle γ with respect to the optical axis of the reflecting mirror 9
The angle range of is 45 ° ≦ γ ≦ 75 °. Angle θ formed by the two reflecting mirror surfaces of the fourth reflecting mirror 10
The angle range will be described. If θ is not 45 ° or more, the light flux sent from the reflecting mirror 31 to the photosensitive drum 11 may come into contact with the reflecting mirror 30, and in order to avoid it, the focal length must be long and the exposure optical system is enlarged. It will be. If θ is not smaller than 90 °, the optical axis from the third reflecting mirror 9 to the reflecting mirror 30 of the fourth reflecting mirror and the optical axis from the reflecting mirror 31 to the photosensitive drum 11 can be crossed. Therefore, the angle range of the angle θ formed by the mirror surfaces of the two reflecting mirrors of the fourth reflecting mirror 10 is 45 ° ≦ θ <90 °. The angle β formed by the optical axis to the surface of the photosensitive drum 11 and the horizontal plane of the photosensitive drum 11, the angle γ with respect to the optical axis from the lens of the third reflecting mirror 9, and the two reflecting mirror surfaces of the fourth reflecting mirror 10. The relationship with the formed angle θ is β = 2 (γ−θ), and the angle range of β is −90 ° <β ≦ 60 °.

As means for changing the magnification and copying, the lens 8 is moved in the optical axis direction to change the distance from the original to the lens and the distance from the lens 8 to the photosensitive drum 11 is adjusted. 4th reflector 1
0 is moved in the direction of the central axis of the angle θ formed by the reflecting mirror 30 and the reflecting mirror 31. This makes it possible to change the magnification while keeping the incident angle β on the photosensitive drum surface constant. The operation of the magnifying power will be described. The lens 8 is moved in the arrow LL direction and the fourth reflecting mirror 10 is moved in the arrow D direction.

Although the number of reflecting mirrors in the exposure optical system is six in the embodiment, the number is not limited.

Further, in the embodiment, the scanning system of the exposure optical system is configured so that the lamp 5 and the first reflecting mirror 6 move below the platen glass 4 on which the original is placed to scan the original.
The platen glass on which the original is placed moves, and the lamp and the reflector may be fixed.

The two reflecting mirrors 30 of the fourth reflecting mirror 10 are also included.
And 31 may not be installed on the same support, but may be separate supports.

[0025]

As described above, according to the present invention, the second reflecting mirror is arranged on the right side of the lens, the third reflecting mirror is arranged on the left side of the lens, and the fourth reflecting mirror is arranged under the third reflecting mirror. As a result, by taking into consideration the downsizing of the copier and the effective use of the space used by the copier, the fixing mechanism located above the photoconductor drum is different from the image formation mechanism in which the photoconductor drum is arranged on the left side of the image formation mechanism. It is possible to effectively use the space above and to the left of the machine and the paper ejection device, and the height and length of the exposure optical system should be the same as the exposure optical system of conventional copying machines without increasing the lens focal length. During zooming, the distance between the lens and the photoconductor drum can be adjusted by moving the fourth reflecting mirror composed of two reflecting mirrors in the direction of the central axis of the angle θ formed by the two reflecting mirror surfaces. . Further, in the developing device which requires an irradiation angle β from the direction of −90 ° to 90 ° with respect to the horizontal plane of the photosensitive drum in the developing device, the developing device has a mirror surface of the third reflecting mirror and an optical axis from the lens. The angle γ formed by and is 45 ° ≤
Within the angle range of γ ≦ 75 °, and the angle θ formed by the two reflecting mirror surfaces of the fourth reflecting mirror is set within the angle range of 45 ° ≦ γ <90 °, ±
By enabling irradiation in the range of -90 ° <β ≤ 60 ° including the best irradiation angle of 0 °, it is suitable for an image forming mechanism in consideration of downsizing of the copying machine and effective use of the space used by the copying machine. An exposure optical system can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a copying machine having an optical device according to the present invention.

FIG. 2 is a sectional view showing a main part of an exposure optical system according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a main part of an exposure optical system of a conventional copying machine.

[Explanation of symbols]

 1 exposure optical system 2 image forming mechanism 3 paper feeding mechanism 4 platen glass 5 lamp 6 first reflecting mirror 7 second reflecting mirror 8 lens 9 third reflecting mirror 10 fourth reflecting mirror 11 photoconductor drum 12 charging means 13 side erase 14 developing device 15 transfer means 16 cleaning means 30 reflecting mirror 31 reflecting mirror

Claims (2)

[Claims] 1. A first reflecting means for scanning an original image, a second reflecting means for reflecting the incident light from the first reflecting means, and a first reflecting means for reflecting the incident light from the second reflecting means through a lens. Three reflecting means and a fourth reflecting means for reflecting the incident light from the third reflecting means and irradiating the photosensitive drum to the photosensitive drum are provided, and the incident optical axis incident through the lens is irradiated to the photosensitive drum. The reflecting means are arranged so that the incident optical axes intersect, and the two reflecting mirrors of the fourth reflecting means are arranged so that the angle θ is 45 ° ≦ θ <90 °. An optical device characterized in that an angle β of the irradiation light to the body drum is irradiated within a range of −90 ° ≦ β ≦ 60 ° with respect to a horizontal plane of the photosensitive drum. 2. The optical device according to claim 1, wherein the fourth reflecting means is arranged so as to be movable in the direction of the central axis of the angle θ.