JPS6025056Y2 - image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that forms an image by projecting a light image from an original film onto a recording medium.

2. Description of the Related Art Conventionally, various image forming apparatuses have been proposed that form an image by exposing a recording medium such as a photoreceptor to a light image based on electrophotography or the like.

The thickness of the aperture mask that supports color reversal film, etc. is defined as 1.0 or more and 3.2 or less, as shown in the table of Sections 4 and 3 of JIS-B7163. There are various materials such as plastics and metals, so they are not constant.

Therefore, when a photographic film supported by the aperture mask is placed on a document table or the like to obtain a copied image, the position of the photographic film is not constant, and the projection image projected onto the photoreceptor is The focus is not consistent, making it difficult to obtain high-quality images.

Therefore, conventional electrophotographic copying devices for photographic film project the photographic film image on the document mounting table onto a set of monitor screens, and adjust the focus by operating the projection lens etc. while viewing the projected image. It is taken.

With this method, it is not possible to start copying immediately after placing the photographic film on the document table, which requires time and effort to adjust the focus, and requires a device called a monitor screen, which increases the overall size of the device. requires a complicated mechanism on top.

The present invention has been developed in view of the above points.

That is, the present invention provides a device that can automatically set the film position to the normal position simply by setting the original film supported by aperture masks of different thicknesses on the document table. .

The original film thickness referred to in the present invention also refers to the mask thickness when the film is held by an aperture mask.

Hereinafter, details of the present invention will be explained using specific examples with reference to the drawings.

FIG. 1 is a perspective view illustrating a specific example image forming apparatus based on the present invention.

In the figure, photoreceptor drum 1 is composed of a three-layered photoreceptor having a photoconductive layer made of CdS.

The photosensitive drum 1 is rotatably supported by a shaft 2, and starts rotating in the direction of an arrow 3 in response to a copy operation command.

When the photoreceptor drum 1 rotates to a predetermined position, the photographic film 5 supported by the aperture mask 4 moves synchronously with the arrow at a speed proportional to the magnification of the image projected onto the photoreceptor drum 1. Scanned in 6 directions.

The photographic film 5 supported by the aperture mask 4 is exposed to light by an illumination section A comprising a reflector lamp 7, a condenser 8, a first mirror 9, and a condenser 10.

The image on the photographic film 5 includes a lens 11, a second mirror 12,
After passing through the third mirror 13, if necessary, the light is separated into colors by a color separation filter 14 for color copying, and further passes through the fourth mirror 15, where it is imaged on the photosensitive drum 1 by the exposure section 16.

Before forming a latent image, the photoreceptor drum 1 is freed of residual charges by a static eliminator 17, then positively (+) charged by a primary charger 18, and then exposed to light by an illumination lamp 7 in the exposure section 16. The image on the photographic film 5 is subjected to slit exposure.

Simultaneously with this exposure, discharge with a polarity opposite to that of alternating current or primary charging is performed in a discharger 19.

Thereafter, a contrasting electrostatic latent image is formed on the photoreceptor drum 1 by further full-surface exposure using the full-surface exposure lamp 20.

The electrostatic latent image on the photosensitive drum 1 is visualized as a toner image in the developing section 21 .

This developing section 21 is composed of three developers: a yellow developer 21a, a magenta developer 21b, and a cyan developer 21c1. An image is obtained.

The plain paper transfer material 22 is stored in a cassette, for example, and the transfer material 22 in the cassette is fed into the apparatus by a single-sheet feed roller 23, and is timed with the developed image by a register roller 24, and then It passes through the feed roller 25 and reaches the transfer drum 26.

Further, the leading end of the transfer material 22 is gripped by a gripper 27 attached to the transfer drum 26, and the transfer material 22 is gripped by the transfer drum 26.

In the transfer section, while the transfer material 22 passes between the transfer corona discharger 28 and the photosensitive drum 1, on the transfer material 22,
The toner image on the photosensitive drum 1 is transferred.

The gripper 27 rotates the transfer material 22 a required number of times while gripping the transfer drum 26, and each time the gripper 27 passes through the transfer corona discharger 28, toner images of each color are transferred in an overlapping manner.

After the transfer is completed, the transfer material 22 is released from the gripper 27 and guided to the conveyor belt 30 by the operation of the separating claws 29.

The transfer material 22 is guided to fixing rollers 31 and 32, and after the toner image is fixed thereon by heat and pressure by the pair of rollers, the transfer material 22 is discharged from the apparatus.

On the other hand, after the transfer, the photosensitive drum 1 is cleaned of residual toner on its surface by a cleaning means 33 constituted by an elastic blade, and the process proceeds to the next latent image forming cycle.

Generally, the aperture mask that supports photographic film is made of various materials such as paper, plastic, and metal, as mentioned earlier, and varies depending on the manufacturer. 1.0 or more, 3. It is specified as a probe and is not constant.

When a photographic film supported by this aperture mask is placed on a document table, the position of the film varies depending on the thickness of the aperture mask, which requires complicated operations and devices for focusing. .

In the device of the present invention, the above-mentioned problem has been satisfactorily solved by the configuration described below.

First, the method of setting the film position in the apparatus of the present invention will be explained.

In FIG. 2, 41 is a photographic film, 42 is a projection lens, and 43 is a photosensitive drum.

In the state shown in the figure, that is, the distance a1 from the photographic film 41 to the projection lens 42, and the distance a1 from the projection lens 42 to the photosensitive drum 4.
The optical position has already been set up to a distance of 3.

At this time, the magnification of the image of the photographic film 41 projected onto the photosensitive drum 43 is expressed as b/a.

However, as shown in FIG.
The distance C of the photographic film 45 held between the original plate 46 and the original table 46 changes depending on the thickness d of the aperture mask 44 .

As this distance C changes, the distance a shown in FIG. 2 changes, and it becomes necessary to readjust the focus every time the thickness of the aperture mask changes.

Generally, the structure of the photographic film sandwiched between the aperture masks is as shown in FIG. It is located approximately in Nakafu.

That is, C=:=d/2.

Therefore, in the apparatus of the present invention, the height of the document mounting table is adjusted to automatically set the distance a in FIG. 2.

The film setting mechanism in the apparatus according to the present invention will be explained in more detail with reference to the drawings.

In FIG. 4, reference numeral 51 denotes a document placing table made of a transparent member, 52 a photographic film held between an aperture mask 53, and 54 positioned above the aperture mask 53. This is a document holding plate made of a transparent member that fixes the document 53.

The document mounting table 51 and the document holding plate 54 are attached to the photographic film 5.
While holding the aperture mask 53 supporting 2,
It is provided so as to be integrally movable in parallel in the direction of arrow 55.

Reference numeral 56 denotes a leaf spring that is fixed to the support member 57 and acts to push down the original plate 51, the photographic film 52, the aperture mask 53, and the original pressing plate 54 as one unit.

The support member 57 is provided with an opening 57a that guides the illumination light F to the photographic film 52.

Reference numeral 58 is a positioning lever that is rotatably supported around a shaft 59 fixed to the main body of the apparatus.

An elongated hole 58a is provided at one end of the positioning lever 58, and engages with a dowel 61 fixed to a first positioning member 60 for positioning the document mounting table 51. , is engaged with a dowel 63 fixed to a second positioning member 62 for positioning the original holding plate 54.

The first positioning member 60 is movable linearly in the direction of arrow 64, and the second positioning member 62 is movable linearly in the direction of arrow 65. It is set.

If the thickness of the aperture mask 53 changes and is thinner than the aperture mask shown in FIG. When pressed by a support member 57 with a spring 56, it comes into contact with the document mounting table 51 and the document holding plate 54, respectively.

The positions of the first and second positioning members 60, 62 are set by raising the first positioning member 60 and lowering the second positioning member 62 by 172, which is the difference in thickness of the aperture mask.

At this time, the position of the photographic film 52 is always fixed, unchanged from the previous aperture mask position.

FIG. 5 shows a further modification, and to avoid duplication of explanation, the same members as in FIG. 4 are designated by the same numbers.

A pinion gear 66 is rotatably supported around a shaft 67.

Reference numeral 68 denotes a first positioning member for positioning the original table 51, which has a rack 69 that engages with the pinion gear 66, and is configured to be movable linearly in the direction of arrow 70.

Reference numeral 71 denotes a second positioning member for positioning the original holding plate 54, which has a rack 72 that engages with the pinion gear 66, and is configured to be movable linearly in the direction of arrow Ffi73.

With the above configuration, the thickness of the aperture mask 53 is detected and the first and second positioning members 68, 71 are moved by 172, which is the difference in thickness, as in the embodiment shown in FIG. Maintain a constant position of the photographic film 52.

As described above, the apparatus of the present invention makes it possible to automatically maintain the position of the photographic film at the optimum position, thereby promoting good image formation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a specific example image forming apparatus according to the present invention;
FIG. 2 is a schematic diagram explaining the relationship between the film and the photoreceptor;
FIG. 3 is an explanatory diagram showing the state of the film on the document table;
FIG. 4 is an explanatory diagram of the film positioning mechanism of a specific example device based on the present invention, and FIG. 5 is an explanatory diagram of a further modified example. 2・
...Axis, 4...Aperture mask, 5.
...Photographic film.

Claims (1)

[Claim for Utility Model Registration] In an image forming device that forms an image by projecting a light image from an original film onto a recording medium, the direction in which the original film is held and the distance between the original film and the lens can be changed. A first positioning member that is still in contact with the original placing member and movable in the above direction, and a first positioning member that is movable in the above direction and is movable in the above direction, a second positioning member that abuts; a means for mechanically connecting the positioning member and the second positioning member so that they move in conjunction with each other by the same distance in opposite directions; and a document placement device holding an original film. The member and the document holding member are each attached to the above-mentioned No. 1. An image forming apparatus comprising: means for biasing the second positioning member into contact with the second positioning member.