JPS61284750A - Copying machine - Google Patents

Abstract

PURPOSE:To prevent completely illumination light from being reflected by a slit and incident and to obtain image of high quality by employing a plane surface opposite the slit of the 1st Fresnel lens of a copying machine with a function which forms a white frame at the end part of a projection image, and then forming plural small lenses which have a specific Fresnel lens on the opposite surface from the plane surface. CONSTITUTION:The 1st Fresnel lens F1 is so formed that plural small lens surfaces (c) and (d) which have different Fresnel angles and make projection light incident in parallel to the axis of a photosensitive drum consist of a top- side half surface 12 and a reverse-side half surface 13 symmetrical about an optical axis 11 set at the center part of the Fresnel lens body 10. Therefore, reverse surfaces (e) and (f) of a surface where the small lens surfaces (c) and (d) of the Fresnel lens body 10 are arrayed annularly along the lengthwise direction of the photosensitive drum are formed in a plane shape. Consequently, the illumination light l which is irradiated by an original illumination lamp 9 and strikes on the small surface (c) of the reverse half surface 12 is reflected regularly in direction deviating from the direction of the slit S as shown by an arrow A.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a copying device that is capable of copying transparent originals such as slide films, and particularly has a function of forming white spots at the edges of projected images. Relating to improvements in copying devices.

(Prior Art) The configuration of a conventional copying apparatus capable of transmitting and enlarging a transparent original such as a slide film and copying the projected image in addition to normal original copying will be explained based on FIGS. 2 to 6.
As shown in FIG. 2, a Fresnel lens F is disposed on the document table glass 2 of the copying device 1, and the nine-projection light that is enlarged and projected by the slide projector 3 is changed in its optical path by the reflection mirror 4 and then passed through the Fresnel lens. After being incident on F, a projected image is formed on a photosensitive drum 6 through an imaging lens 5, as shown in FIG. As shown in FIG. 4, the Fresnel lens F includes a first Fresnel lens F1 having a group of small lenses formed on one side so as to condense projected light in the direction of the axis a of the photoreceptor drum 6, and a fifth Fresnel lens F1. As shown in the figure, the first lens is composed of a second Fresnel lens F having a group of small lenses formed on one side so as to condense the projection light Lt in the longitudinal direction bK of the photoconductor dome 6. w42 fresnel lens FstoF
*C, M As shown in Figure 6, the small lens surfaces face each other,
The small lenses are assembled with their longitudinal directions perpendicular to each other, and the light is focused by the projection lens 8 and projected onto the slide film 7.
A projected image is formed on the photosensitive drum 6 as shown in FIG.

On the other hand, in the main body of the copying apparatus 1, an original illumination lander 9 used for normal original copying is provided.
Reference numeral 9 denotes a slide film 7t, which is also turned on when projecting and copying, and acts to form white spots at the edges of the projected copy image.

(Problems to be Solved by the Invention) However, the conventional copying apparatus 1 configured as described above
When the original illumination lamp 9 is turned on to form a white mark, the lamp 9 (DRFIA light 11d)
, a1 is reflected by each surface of the small lens of the Fresnel lens F1, and the reflected light is reflected in different directions depending on the respective different Fresnel angles. Therefore, as shown in Fig. 3117, a part of the illumination light j This invention has been devised in view of the current situation, and its purpose is to , the occurrence of cast image defects in a copying machine that has the function of copying a transparent original image such as a slide film using a Fresnel lens, and also has the function of forming white marks at the edges of this projected image. It is an object of the present invention to provide a copying apparatus with a simple configuration and low cost that can solve the above problems.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a transparent original such as a slide film is projected by a projection device, and this projected light is directed in the axial direction of the photoreceptor drum. The M1 Fresnel lens focuses light and the second lens focuses light in the longitudinal direction of the photoreceptor drum.
A Fresnel lens condenses light to form a projected image on the drum, and when copying the projected image, a document illumination land is turned on to form a white spot at the edge of the image. The small lens surface of the M1 Fresnel lens in a copying machine is formed on the front half surface and the back half surface with the center part as a boundary, and the illumination light of the document illumination rande is formed on the small lens surface formed on the front upper half surface of the first Fresnel lens. It is arranged so that it is reflected on the lens surface.

(Embodiment) Hereinafter, the present invention will be described in detail based on an embodiment shown in FIG.

The copying apparatus according to this embodiment includes a first Fresnel lens F,
The structure and operation other than the structure are exactly the same as the structure and operation of the conventional copying apparatus 1 described above. A detailed explanation thereof will be omitted here.

As shown in FIG. 1, the first Fresnel lens F1 according to this embodiment includes a plurality of small lens surfaces C having different Fresnel angles that allow projection light to enter parallel to the axial direction of a photoreceptor drum (not shown). and d are the front half surface 12 and the back half surface 1 with the optical axis 11 set at the center of the Fresnel lens body lO as a boundary.
It is formed symmetrically with 3. Therefore, the back surface e of the surface on which the small lens surfaces c and d of the Fresnel lens body 10 are arranged in an annular shape along the longitudinal direction of the photoreceptor drum.

-f is formed into a flat plate shape.

The optical axis 11 is set so as to coincide with the optical axis of the projection lens of the slide projector when the Fresnel lens F is sected onto the document table glass.

The M1 Fresnel lens Ftk configured in this manner is arranged so that the small lens surface d formed on the back half surface 13 and the flat plate-shaped portion e on the back side face the small lens surface of the second Fresnel lens F. , and the flat plate-like portion e is positioned in the direction in which the slit S is arranged.

In this way, by arranging the first Fresnel lens Ft t'' in such a manner that the longitudinal direction of its small lens surface is perpendicular to the longitudinal direction of the small lens surface of the second Fresnel lens F1, the document illumination land 9 is illuminated. The illumination light g that hits the small lens surface eK of the front half surface 12 is specularly reflected in a direction away from the slit S direction, as shown by arrow A in FIG. 1, and is also reflected by the small lens surface e of the back half surface 13. As in the conventional case, the illumination light l is directed in a direction (
It is reflected in the direction of the arrow in Figure 1).

(Effects of the Invention) As explained above, the present invention has the function of copying a transparent original image such as a slide film using a Fresnel lens, and also has the function of forming white spots at the edges of the projected image. The surface of the first Fresnel lens of the copying device that faces the slit is a flat surface, and a plurality of small lenses having a predetermined Fresnel angle are formed on the opposite surface of the flat surface, so that illumination light is reflected on the slit. As a result, a cost image does not occur and a stable, high-quality image can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing the configuration of essential parts of a copying apparatus according to an embodiment of the present invention, FIG. 2 is a side view of a conventional copying apparatus having a function of copying a slide projection image, and FIG. 3 is a conventional copying apparatus. A principle explanatory diagram showing how a slide projection image is formed on a photoreceptor drum using a Fresnel lens, Fig. 4 is an explanatory diagram of the operation of the conventional first Fresnel lens, and Fig. 5 is an explanatory diagram of the operation of the JR2 Fresnel lens. 6 is an exploded perspective view showing a combination of a first Fresnel lens and a second Fresnel lens, and FIG. 7 is an explanatory diagram schematically showing the structure and operation of the main parts of a conventional copying apparatus. 1... Copying device 3... Projection device 5...
Imaging lens 6... Photosensitive drum 7... Slide film 9... Original illumination land 12...
・Front half surface 13... Back half surface a... Axis center of photoreceptor drum b... Longitudinal direction of photoreceptor drum c
, d... Small lens surface F... Fresnel lens F,... First Fresnel lens F,... Second Fresnel lens L... Projection light g... Illumination light patent applicant Canon Corporation ,,,',knee,y Fig. 1 Fig. 2 Fig. 6 Fig. 7

Claims (1)

[Claims] A first Fresnel lens projects a transparent original such as a slide film using a projection device, and focuses the projected light in the axial direction of the photoreceptor drum, and a second Fresnel lens focuses the light in the longitudinal direction of the photoreceptor drum. A copying machine configured to collect light and form a projected image on the same drum, and to turn on a document illumination land when copying the projected image to form a white mark at the edge of the image. In the apparatus, the first
The Fresnel lens has small lens surfaces formed on the front half and the back half of the Fresnel lens, with the center as a boundary, and the illumination light from the document illumination rande is reflected on the small lens surfaces formed on the upper half of the front side of the first Fresnel lens. A copying device characterized in that it is arranged as follows.