JPS6033548A - Image forming device - Google Patents

Abstract

PURPOSE:To perform variable magnification projecting operation extremely with ease by moving a photosensitive belt at a speed determined by the scanning speed and magnification of an image forming system during magnification variation. CONSTITUTION:A moving table 5 of image-forming means where image forming means 9a-9c and their rotating disk shutters 10a-10c are fixed is provided under a platen 2 slidably on a guide rail 4. The speed of the photosensitive belt 11 is represented as V=v(1-alpha), where V is the moving speed of te belt 11 and (v) and alpha are the moving speed and magnification variation rate of the image forming system. For example, the photosensitive belt 11 and image forming system are moved in the same direction at said speed V during reduced image formation, a specific shutter is opened to form a latent image, and then the belt 11 is moved in a process direction. The reverse operation is performed during enlarged image formation. Thus, variable magnification projecting operation is performed extremely with ease.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses an image forming apparatus capable of variable magnification projection, particularly an imaging system consisting of an array of small-diameter imaging elements, to project image light onto an endless belt-like or sheet-like photoreceptor. The present invention relates to a stationary document table type image forming apparatus capable of variable magnification projection that forms an electrostatic latent image, develops it, and transfers it to a transfer device.

゛ In image forming devices, a focusing light transmission element (product name:
An imaging system is known in which a plurality of SELFOCs are arranged in a predetermined direction, each element projects a portion of the image, and the entire image is projected by scanning the image. Further, an element array imaging system for variable magnification projection is disclosed in Japanese Patent Application Laid-Open No. 16415/1983. In such an imaging system, each element is arranged in a fan-shape symmetrically from the center along the width of the image, and the lengths of the elements are different in the center and periphery of the imaging system. . Furthermore, in addition to the above-mentioned elements, a bar lens system or the like can be used as the small-diameter imaging element.

Conventionally, in a document platen movable image forming apparatus capable of variable magnification projection using an imaging system consisting of a small-diameter imaging element, where α is the copy magnification, (document platen speed) = (photoreceptor speed) × -, α It was driving the document table. This is because the moving speed of the document table can be changed independently of the moving speed of the photoreceptor.

However, in the stationary document table device, the photosensitive belt and the document table are stationary during exposure, so the projection magnification is limited to the same size.

For this reason, measures have been taken to change the projection magnification by using an imaging system using a zoom lens or the like and changing the projection magnification by changing the focal length. Compared to an apparatus using a small-diameter imaging element array, the optical system is complicated and large, and the cost is increased.

The present invention aims to eliminate the drawbacks of the conventional apparatus described above, by moving the photoreceptor belt at a speed determined by the scanning speed of the imaging system and the magnification during exposure during zooming.
The present invention focuses on the fact that a variable magnification image can be formed on a photosensitive belt, thereby providing a stationary document table type image forming apparatus capable of variable magnification projection.

The invention will be explained below by way of example embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an embodiment of an image forming apparatus according to the present invention. In the figure, an original 1 to be copied is placed on a transparent original table 2 fixed in a fixed position and is held in close contact with a pressure bonding plate (not shown). A corona discharger 6 operates when scanning an original to uniformly charge the surface of the photoreceptor, a lamp 8 having a reflective concave mirror 7 placed behind it for illuminating the original, and a light image of the original onto the surface of the photoreceptor. An imaging means moving stage 5 on which imaging means 9a, 9b, and 9c for slit exposure are fixed as a group is slidably fitted on a linear guide rail 4, and is moved parallel to the document table 2 at a constant speed in a constant direction. Moved repeatedly. Here, the imaging means 9a.

9b and 9c are transparent γC rod-shaped bodies whose refractive index gradually decreases in a quadratic manner from the center outward in the radial direction, and are rod-shaped converging light transmission elements ( For example, it is made by bundling a large number of products (product name: ``Selfoc'') in one or more parallel layers closely in an array.
The compound eye is configured to form an erect real image of an object at equal magnification as an imaging means.

The imaging means 9a, 9b, and 9c each have a length sufficient to cover the width of the document 1 in the direction perpendicular to the direction of movement, and are spaced at intervals approximately equal to the forward travel distance of the platform 5 in the direction of movement. and are arranged parallel to each other. Furthermore, the imaging means 9a
, 9b, and 9c are integrally molded with their respective dustproof glasses, and in this embodiment, for example, 9a, 9
It is assumed that the images b and 9c are configured for enlargement, same size, and reduction, respectively. Imaging means 9a.

A rotary plate shutter 10a is located close to the incident surface of 9b and 9c.
.

10b and 10c are provided. The shutter selectively rotates by a predetermined angle in accordance with a user's command to open and close an optical path between the image forming means and the document, each having a different magnification. - When the optical path is closed, the shutter 10a
, 10b and 10c diffusely reflect the light from the lamp 8, respectively. Reference numeral 11 denotes a photosensitive belt having an electrophotographic photoreceptor formed of a conductive layer and a photoconductive layer on an endless belt, and is stretched over three feed rollers 12a, 12b, and 12c. , is engaged with and driven by a motor (not shown). Reference numeral 13 denotes a developing device for developing the electrostatic latent image formed on the photoreceptor, and supplies toner charged to the opposite polarity to the latent image onto the photoreceptor surface.

The transfer paper 3 is fed from the paper feed section 14 by a transfer paper conveying means that is operated in synchronization with the operation of the developing device 13, respectively.
It comes into contact with the toner image formed on the photosensitive belt 11 at the position of the roller 12c. At this time, the transfer corona discharger 15 applies a corona discharge of opposite polarity to the toner to the back surface of the transfer paper 3.
Improving the transfer efficiency of developed images. After the transfer, the transfer paper 3 is passed between the heat rollers 16, where the toner image is fixed, and then discharged to the storage section 17. After the transfer, the photoreceptor belt 11 is cleaned by wiping off residual toner by an elastic blade 18 made of rubber or the like fixed to the main body so as to be in sliding contact with the belt surface.

The operation of the device according to the present invention will now be described. Now, when the user turns on the equal confidence switch of the magnification selection device shown in the figure, the photoreceptor belt or sheet 1
1 stops, and movement 5 performs charging and exposure for the original. In the imaging means moving table 5 according to the present invention, the lower end of the reflective concave mirror 7 is cut off, and the lamp 8 also serves as a pre-exposure function.

In other words, the internal resistance of the photoreceptor is lowered, the next charging operation is performed smoothly, and density unevenness and roughness are prevented from occurring in the image. Further, when the magnification is equal, the equal borrow shutter 9I) is opened and the other shutters are controlled in conjunction with the operation of the magnification selection device. After exposure, belt 11 is driven counterclockwise in the figure and an image is formed by the process described above.

During continuous copying, belt 1 is turned off when the first sheet is developed.
1 stops, performs the second exposure, and starts driving again.

The process may be such that the first development is transferred while the second latent image is developed, and the third exposure is performed when these processes are completed.

As described above, in the case of equal-magnification copying, a high quality electrostatic latent image is formed on the photoreceptor belt by stopping the photoreceptor belt when forming the latent image.

Next, in the apparatus according to the present invention, the operation in the case of variable magnification transfer will be described. When the user turns on the variable magnification switch (for example, for enlarging) (not shown), the shutter for variable magnification (here In this case, shutter 9c) is opened for exposure, and the other two shutters are closed.

Next, the feeding speed of the belt photoreceptor during the magnification changing operation will be described with reference to FIG. 3, which is a conceptual diagram of the present invention, for an embodiment of an optical system with a fixed document table, that is, an image forming means moving system.

Now, assume that the moving speed of the image forming means (stand 5) is V, the length of the original 1 is a, the length of the latent image is S, and the speed of the belt photoreceptor is V. From Fig. 2a, the moving speed V of the imaging means is v = a/l ・
・・・・・・・・・・・・・・・ ■Here, the magnification ratio α is α=b/a ・・・・・・・・・・・・・・・ ■. However, t is time. From ■×■, αv = b
/l ・・・・・・・・・・・・ ■Belt photoreceptor speed ■ is V=(a-b)/l =a/l-b/1 =V-αv(','■ )=v(1-α)・・・・・・・・・・・・・・・ ■As you can see from formula ■, when expanding (α>1), V=-v(
1-α), and the belt photoreceptor advances in the opposite direction to the scanning direction of the optical system, that is, in the process direction described above in this embodiment (FIG. 2-c). At the same magnification (α-1), it becomes -0, the belt photoreceptor is in a stationary state, and the optical system scans the original at a predetermined speed V (Fig. 2-a). When reducing,
V-v (1-α) and y (the scanning direction of the belt photoreceptor and the optical system are the same as shown in Figure 2-b), that is, the direction is opposite to the process direction described above, and in this case, the photosensitive The belt first moves at a relative speed in the same direction as the scanning direction, and after forming a predetermined reduced latent image, the running direction of the belt is reversed to the normal image forming process direction to carry out the predetermined process. The traveling speed and direction of the photosensitive belt are controlled in conjunction with the operation of the selection switch.

FIG. 3 is a block diagram showing the flow of functions of the magnification selection device A of the image forming apparatus according to the present invention, in which the computer B operates in response to selection operation of any of the magnification selection switches a, b, and c of the device. At the same time, a desired shutter C is opened and the other shutters are closed, and at the same time, the direction and speed of the photoreceptor belt are selected and the operation is instructed to the drive device.

In the above, there are three imaging systems with different projection magnifications on the imaging means moving table.
Although an example in which multiple imaging systems are provided has been described, it is of course possible to include an arbitrary number of imaging systems, so that an arbitrary projection magnification can be obtained. In addition, in this embodiment, in the case of full-size copying, the photoreceptor belt was stopped during exposure to form a latent image, but if the counterclockwise running of the photoreceptor belt in the figure is taken as the positive rotation direction, then from equation (2), As is clear, (1-α) x (scanning speed)
It is also possible to perform continuous copying by rotating at a speed of γC.

In the above embodiment, an electrophotographic copying machine has been described, but the present invention can also be applied to other types of image forming apparatuses.

As described above, since the present invention has a novel configuration and function, it is possible to perform variable magnification projection work as desired and extremely easily in an image forming apparatus with a fixed document table, which was difficult to perform in the past. It has a remarkable effect.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of one embodiment of an image forming apparatus according to the present invention, and Figs. 2-a, 2-b, and 2-c are functional conceptual diagrams of the present invention, which are equal to the same size, reduced, and enlarged, respectively. FIG. 3 is a block diagram showing the function of the magnification selection device according to the present invention. 1...Original 2...Document table 3-...Transfer paper 4...Guide rail 5...Imaging means moving table 6...Corona discharger 7...Reflecting concave mirror
8...Lamps 9a, b, c...Imaging means 10a, b, c...Shutter 11-1. Photosensitive belt 12a, b, c-・Feed roller 13...Developer 14...Paper feed section 15...Corona discharger 16...Heat roller 17...
・Accommodating part 18...Blade 11- Fig. 2a Fig. 2b Fig. 2c Fig. 3

Claims (1)

[Claims] A stationary document tray, an endless belt photoreceptor disposed so as to be able to run parallel to the document tray, and a space between the document tray and the belt photoreceptor (= small-diameter imaging element array arranged). the magnification changeable RZ imaging system moves at a predetermined speed to scan the document on the document mounting table; An image forming apparatus that moves at a speed determined by a scanning speed and a change magnification of the coupling system during operation.