JPS605933B2 - Copy machine magnification conversion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying machine capable of making copies not only at the same magnification but also in reduction and enlargement, and more particularly to a magnification conversion device for changing lenses when copying at different magnifications.

In general, most copying machines perform 1:1 copying of originals, but some copying machines also have a reduction or enlargement function.

The above reduction or enlargement functions include the original holding section, optical system,
At least two elements of the photoreceptor may be moved to change their positions. However, the photoreceptor cannot be moved, and it is also difficult to change the position of the original holding section (original table). Therefore, in the past, copying using the bowl 4 or enlarging copying has been realized by changing the position of the optical system located between the document holding section and the photoreceptor. When performing reduction or enlargement copying, the present invention performs reduction or enlargement copying by arranging a lens with a different focal length in the optical path, which is different from that used for full-size copying.

Here, when replacing the lens, if the interchangeable lens is placed at the same position as the 1x lens, the optical path length from the document surface to the lens is usually the same as that at 1x magnification. Therefore, it is necessary to change the optical path length from the lens to the photoreceptor surface in accordance with the focal length of the interchangeable lens. Generally, the lens for reduction copying is selected to have a focal length shorter than the lens for full-size copying, and is switched to the same position as the lens for full-size copying. At this time, the optical path length between the reduction lens and the photosensitive surface needs to be shortened in accordance with the reduction ratio. This can be accomplished by changing the position of a reflecting mirror located between the lens and the photoreceptor surface. In the case of enlarged copying, a lens opposite to that described above may be used to ensure a long optical path length between the lens and the photoreceptor surface. Here, the problem is that it is necessary to match the angle of reflection of the light reflected from the document surface with the angle of irradiation of the light image onto the photosensitive surface.

That is, it is necessary to match the above-mentioned reflection angle and illumination angle not only when making a full size copy but also when making a reduced copy. Therefore, various proposals have been made in the related field. The present invention provides a magnification conversion Z conversion device that allows the reflection angle and the illumination angle to match with a simple configuration even when the magnification is converted.

That is, in the present invention, the lens for variable magnification is arranged in a manner that corresponds to the optical axis of the lens for 1:1 copying, and the irradiation angle on the photosensitive surface is the same as that for 1:1 copying. The reflection mirror is tilted so that it follows the optical path during the same-size copy Z. The present invention is characterized in that the optical axis of the lens for variable magnification is narrowed, and by this narrowing, the optical path length between the lens and the photosensitive surface can be easily secured in accordance with the magnification. Also, due to the value of the lens, the optical path 2 facing the photosensitive surface is largely shifted, and the irradiation angle does not match the reflection angle. However, by tilting the reflection mirror according to the angle at which the optical axis is tilted, the irradiation angle and It is possible to match the reflection angle. In other words, the tilted reflecting mirror corrects the optical path to follow the optical path of light irradiating the photosensitive surface during full-size copying, and the irradiation angle to the photosensitive surface is kept the same as when copying at full-size regardless of displacement. . Further, in the present invention, the variable magnification lens and the same lens are supported in a horizontal position, and by sliding in the horizontal direction, each lens is placed in the normal optical path.

That is, lenses can be replaced simply by using the space of the conventional optical system. In addition, since it only needs to be slid, the positioning, sliding mechanism, etc. are extremely simple. Further, the tilted reflection mirror 3 for optical path correction can be disposed in the optical path by interlocking with the above-mentioned slide, and its structure becomes simple. Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a sectional view showing the entire internal structure of a copying machine according to the present invention. Referring to the figure, an overview of the copying machine will be explained 4. In the figure, reference numeral 1 denotes an original table provided at the upper part of the main body of the copying machine, 2 an original cover, and 3 an illumination device consisting of a reflector and a lamp for illuminating the original on the original table. The light reflected from the original by the illumination of the illumination device 3 is reflected from the first
The light is guided to the mirror lens 6 via the movable mirror 4 and the second movable mirror 5. Further, the optical image from the mirror lens 6 is transmitted to the photoreceptor drum 8 via the reflection mirror 7.
imaged on a surface. In this case, each of the above-mentioned optical systems is arranged so that the reflection angle 8 of the reflected light from the original and the irradiation angle 82 of the reflection mirror 7 onto the photosensitive surface are the same at the same magnification. Scanning of the document on the surface of the document table 1 is performed by moving the first movable mirror 4 along the document table 1. At this time, the lighting device 3 is moved at the same time. Further, the movement of the first movable mirror 4 changes the optical path length to the lens 6, but the second movable mirror 5 compensates for this change. The second movable mirror 5 moves in the same direction and parallel to the first movable mirror 4 at half the speed of the first movable mirror 4 to compensate for the optical path length.
The above is the structure of the optical system. The photoreceptor drum 8 is a photoreceptor having a three-layer structure including a conductive support, a photoconductive layer, and a light-transmitting insulating layer.

The photosensitive drum 8 is uniformly charged by a first corona charger 9 before being irradiated with the above-mentioned light image, and is further irradiated with the light image at the same time as corona charging by the second corona charger 10. Furthermore, the entire surface of the photoreceptor drum 8 is uniformly exposed by the action of the uniform exposure lamp 11. As a result, an electrostatic latent image corresponding to the light image irradiation (original) is formed on the photoreceptor surface. This latent image is finished as a toner image in the next developing device 12.The toner image is also stored in a cassette 13 and transferred as a corona onto a transfer sheet that is appropriately fed by a sheet feeding and conveying means. The toner image is transferred by the action of the charger 14.The paper to which the toner image has been transferred is separated from the surface of the photoreceptor drum by a separating roller 15 and sent to a heat fixing roller 16.Here, the toner on the paper is fixed. The paper that has passed through the fixing roller 6 is discharged onto the 9E paper toilet 17. On the other hand, the charge and toner remaining on the surface of the photoreceptor drum 8 are removed by the charge removal corona charger 18 and the cleaning device 19. When forming a same-size image (latent image) on the surface of the photoreceptor drum 8, the lens 6 is used as the center to remove the image between the document surface and the lens 6. The optical path length of the lens 6 and the photosensitive surface 8 are set to be equal.

For example, when making a reduction copy, a reduction lens (with a focal length shorter than that of the borrowed copy lens described above) is placed at the same position as the lens 6 shown in the figure. The optical path length between this lens and the document surface is the same as in the case of full-size copying. However, the optical path length between the lens and the photosensitive surface is made shorter in accordance with the reduction magnification. That is, it has a rotatable reflecting mirror 20 which is not normally located in the optical path between the fixed mirror 7 and the photosensitive surface (when copying at the same size). This reduction reflecting mirror 20 rises in conjunction with the replacement of the lens 6 (indicated by a dotted line in the figure), and irradiates the photosensitive surface with a light image from the lens. In this case, if the replaced lens has the same optical axis as the same magnification lens, the optical image will move toward the fixed mirror 7 in the same way as the same magnification lens. Therefore, even if the fixed mirror 7 is moved and tilted so as to move to a position according to the magnification and focus an image on the photoconductor 8 at the same magnification, the irradiation angle to the photoconductor 8 will be the same. Different from double time. Therefore, the optical axis of the reduction lens is directed toward the reduction reflection mirror 20. That is, the optical axis of the lens is tilted to ensure an optical path length that corresponds to the magnification. In addition, since the irradiation angle a2 at which the photoreceptor drum surface is irradiated changes by tilting the lens, the reduction reflecting mirror 20 is tilted and positioned to correct the irradiation angle 82 so that it does not change. FIG. 2 is a perspective view showing a portion of the optical system described above.

In the figure, 6-, 6-2 are in-mirror lenses, and 6-
, are equal borrowing lenses, and 6-2 is a reduction lens.
The lenses 6-, 6-2 are supported by a support member 21 and are arranged in parallel in the horizontal direction. Further, as shown in FIG. 3, the lens 6-2 for reduction copying has the following functions depending on the reduction ratio:
It is supported by the support member 21 so that the optical axis b is inclined with respect to the optical axis a of the lens 6-. Both legs 21-, of the support member 21 are attached to the slide shaft 22-, and the protrusion 2 at the center of the support member 21 is attached to the slide shaft 22-.
1-2 is provided on the slide shaft 22-2. Further, the support material 21 is attached to both the legs 21-, by the slides 22-,
, 22-2.
are secured at each end. Wire 23 connects to motor 24
The pulley 25 is directly connected to the rotating shaft 24-, and the pulleys 26 and 27 are suspended. In addition, the slide shaft 22-,
, 22-2 are provided horizontally, and the motor 24 is fixed to a drum constituting a dark box of the optical system. Further, driven pulleys 26 and 27 are also rotatably supported by the same frame as the motor 24. On the other hand, on one side of the dark box,
If the borrowed lens 6-,
is fixed.

Further, a reduction mirror 20 rotatably held in the optical path between the L fixed mirror and the photosensitive surface is provided in the dark box. The reduction mirror 20 is fixed to a shaft 28 rotatably supported on each side plate of the dark box. Axis 2
8 rotates, the reduction mirror 20 rises and is positioned facing the optical path. That is, a wire 29, one end of which was fixed to the second pulley 25-, at the tip of the pulley 25 of the motor 24, was fixed to the end of the shaft 28 via each driven pulley 30, 31, 32 and a spring 33. It is attached to the lever 34. Therefore, when the motor 24 rotates, the wire 29 is wound around the pulley 25-, causing the shaft 28 to rotate. As a result, the reflecting mirror 20 is raised.
5 is attached. In the configuration as described above, when copying at the same size, the equal-sized lens 6-, is located in the optical path as shown in FIG. 2, and the lens 6-,
As shown in FIG. 4, the reflected light image from the original is directed toward a mirror 7.

Therefore, the reflection mirror 7 irradiates the light image onto the surface of the photosensitive drum 8 at an angle of 82 degrees, which is the same angle as the reflection angle from the document surface of 0. On the other hand, when performing a reduced copy, a corresponding signal is applied to the motor 24.

As a result, the pulley 25 is rotated counterclockwise, and the support member 21 is slid along the slide shafts 22-, 22-2. Therefore, the reduction lens 6-2 is positioned in the optical path. In conjunction with this, the wire-29 is connected to the pulley 25-
, so that the shaft 28 is rotated, and the two reduction mirrors are raised to face each other in the optical path. Here, the optical axis of the reduction lens 6-2 is determined, and the reduction reflection mirror 20 is selected depending on the optical axis of the lens 6-2. That is, as shown in FIG. 4, the light image formed by the reduction lens 6-2 is reflected by the reflection mirror 20 and is positioned in the optical path of the same-magnification reflection mirror 7. is irradiated. As a result, the reflection angle 6 and the irradiation angle 82 can be made the same even during reduction copying, and moreover, accurate reduction copying can be expected without changing at all from the irradiation angle 82 at the same magnification. Note that when switching from reduced copying to full size copying, the motor 24 rotates clockwise to slide the supporting member 21 so that the equal borrowing lens 6- is positioned in the optical path.

In addition, due to the action of the return spring 35,
The shaft 28 is rotated, and the reflecting mirror 20 is removed from the optical path. As explained above, the magnification conversion device according to the present invention performs this by switching lenses, and the variable magnification lens is positioned at the same position as the equal magnification lens by sliding the lens in the horizontal direction. , the space required for switching is small.

In addition, since the optical axis of the lens placed at the same position is tilted with respect to the equally borrowed lens, the necessary optical path length can be easily obtained, and a reflecting mirror is installed in the optical path to correct the tilt of the optical axis. Because it is positioned at an angle, the angle of reflection from the document surface and the irradiation on the photosensitive surface can be matched, and the irradiation angle does not change even when the original size is normal and when the image is changed, resulting in always clear images. can be obtained. Furthermore, since the correction reflection mirror is positioned in the optical path in conjunction with lens switching, the same driving source can be used, simplifying the configuration.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a copying machine according to the present invention, and FIG. 2 is a perspective view showing a diamond part of an optical system according to the present invention. FIG. 3 is a side view showing how each lens is attached, and FIG. 4 is a diagram showing the optical path in the present invention. Code, 1: manuscript table;
3: illumination device, 4: first moving mirror, 5: second moving mirror, 6-,: etc. borrowed mirror lens, 6-2: reduction mirror lens, 7: reflective mirror, 8: photoreceptor Drum, 20: Reduction mirror for 4, 8, 3 reflection angles, 82: Irradiation angle. Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Scope of Claims] 1 Reflected light from an original is imaged on a photosensitive surface through an optical system consisting of a reflecting mirror, a lens, etc., and the reflection angle of the reflected light is made to match the irradiation angle to the photosensitive surface. In a copying machine capable of variable magnification, in which the optical system is positioned and the lens for image formation is replaced with an equal-magnification lens when changing magnification, the optical path length when changing magnification is determined relative to the optical axis of the lens when changing magnification. A variable magnification lens is provided with an optical axis tilted for compensation, and when the variable magnification lens is replaced, the variable magnification lens is arranged to be tilted according to the tilt angle of the optical axis of the lens, and the above-mentioned at the same magnification is A magnification conversion device for a copying machine, comprising a reflecting mirror that reflects a light image onto a photosensitive surface in accordance with an irradiation angle to the photosensitive surface. 2. A magnification conversion device for a copying machine according to claim 1, characterized in that the lenses for equal magnification and variable magnification are arranged laterally and are provided so as to be slidable laterally to switch the lenses. . 3. The magnification conversion device for a copying machine according to claim 2, wherein a reflecting mirror for correcting a deviation of the optical axis is arranged in an inclined manner in the optical path in conjunction with a slide for switching lenses.