JPS60101565A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To control a copy image according to a designated position by varying the surface potential given to a photosensitive body surface by an electrostatic charging means according to the signal of a position on an original surface which is detected by a position detecting means. CONSTITUTION:A photosensitive body 10 is equipped with a charging control means 34 for controlling the operation of the charger 14 which supplies an initial charge, and the amount of charge given to the photosensitive body 10 is adjusted by this charging control means 34. Further, the position detecting means 36 is provided to detect the position designated on the surface of an original 18, and the amount of charge supplied to the photosensitive body 10 is adjusted according to the position on the original surface 6 to control the density of a copy image according to the designated position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrophotographic apparatus using the so-called Carlson process for copying an image of a document surface onto plain paper.

For more details, specify the position on the document surface.
The present invention relates to an electrophotographic apparatus that can adjust the amount of charge on a photoreceptor according to the specified position on the document surface, thereby controlling the density of a copied image according to the specified position.

Conventional Structure and Its Problems FIG. 1 shows a schematic structure of a main part of an example of a conventional electrophotographic apparatus using the Carlnon process. In FIG. 1, photoreceptor 10 rotates in the direction of arrow 12 when copying is performed, and first, a uniform charge is applied to the surface by corona discharge from charger 14. The document surface 18 of the document 16 is irradiated with light by a fluorescent lamp 2o serving as document irradiation means, and its reflected image is formed on the photoreceptor 10 through an imaging optical system such as an optical fiber/<-22 having a lens effect. The image of the document surface is sequentially exposed on the photoconductor 1Q from the right end to the left end of the document surface 18 in synchronization with the rotation of the photoconductor 1o. In the developing device 24, toner is attached according to the charge distribution of the electrostatic latent image generated on the photoreceptor 10 by exposure of the original surface image, and a developed image is formed on the photoreceptor 1o. This developed image is transferred to the plain paper 11 by the transfer charger 25 to form a copy image, and one of the main factors that determines the density of the copy image is the size of the residual charge of the electrostatic latent image. , and it is well known that this residual charge is determined by the initial amount of charge applied to the photoreceptor 10 by the charger 14.

On the other hand, when obtaining a copy image, there are demands for image control such as adjusting the density or not copying a specific part (that is, bringing the image density of a specific part close to zero). It is conceivable to control the copied image by adjusting the initial charge amount.

Normally, when performing image control,
Increasing or decreasing the concentration by dividing specific areas in 8.

Alternatively, it would be convenient to be able to erase a copy of a document in a specific area or while leaving a specific area.
For this purpose, it is necessary to adjust the initial charge amount by dividing the area within the document surface 18, but conventional electrophotographic devices do not have a function to specify the desired position within the document surface, and it is necessary to adjust the initial charge amount by dividing the area. Since there is no charge control means for adjusting the initial charge amount, it has been difficult to control the copied image.

OBJECTS OF THE INVENTION The present invention eliminates such drawbacks of the prior art by specifying a position on a document.

It is an object of the present invention to provide an electrophotographic apparatus that can adjust the initial charge amount of the photoreceptor according to the specified position on the document surface, and thereby control the copied image according to the specified position.

Structure of the Invention The electrophotographic apparatus of the present invention includes, in addition to a charger for applying an initial charge to a photoreceptor, a charge control means for controlling the operation of the charger. , the number of charges applied to the photoreceptor from the charger can be adjusted.

Furthermore, it is equipped with a position detecting means for detecting a specified position on the document surface, and by specifying a position on the document surface with this position detecting means, the photodetector is exposed according to the specified position on the document surface. By adjusting the amount of charge applied to the body, it is possible to control the density of the copied image according to the specified position.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a perspective view of essential parts showing the structure of an embodiment of the electrophotographic apparatus of the present invention. As shown in FIG. A fluorescent lamp 20 is provided as an original irradiation means for irradiating the original surface 1B of the placed original 16. An optical fiber 22 having a lens effect as an imaging optical system is provided. moves in the direction of arrow 3o in synchronization with the rotation of document placement surface 2.
The image of the original surface is sequentially exposed on the photoreceptor 1o from the right end to the left end of the original surface 18 placed on the side.

Similar to a conventional electrophotographic apparatus, an electrostatic latent image is formed by applying an initial charge to the photoreceptor 10 and exposing the image on the document surface, and the developing device 24 develops toner according to the charge distribution of the electrostatic latent image. is attached to form a visible image on the photoreceptor 1o. In this embodiment, a charge control means 34 is further connected to the charger 14 via a flexible wiring board 33. The charging control means 34 includes a position detection plate 36 on which the original 16 is placed and for detecting a specified position on the original surface 18 of the original 16, and a position detection plate 36 for detecting a specified position on the original surface 18 of the original 16. The flexible wiring boards 37 and 38 are connected to each other via cords 39. Charge control means 34, for example, charger 34
By controlling the corona discharge current from the photoreceptor 1
It is now possible to adjust the amount of initial charge given to zero. The position detection plate 36 also has a coordinate origin 4.
Orthogonal coordinates are formed with the origin at 0 and the X and Y axes. The X-axis and Y-axis are divided at a required interval, and the position on the position detection plate 36 in the xYY plane defined by the X-axis and Y-axis can be coordinated. The original 16 has one end aligned with the coordinate origin 4Q, the original surface 18 facing upward, and the original surface facing the X axis.

An example of specifying a position in the XY plane on the position detection plate 36 along the Y axis will be described with reference to FIG.

If,” 1 point 2 points A (Xl.

Yl), B(x2.Y2), the position detection plate 3
6, the above two points A and B are input to the charge control means 34, and based on this input, the points A (X, , Y1') and C (X2°) indicated by diagonal lines in FIG. Yl
), B (X2.Y2), D (Xl, Y2) i
The calculated rectangular area is calculated and stored as the specified position. The charging control circuit 34 includes, for example, ■ the above-mentioned rectangular area AC;
Leaving the BD and erasing the other document surface images. (2) Erase the document surface image corresponding to the rectangular area ACBD and leave the other parts. (2) Decrease the copy image density of the document surface image corresponding to the rectangular area ACBD. Selection members 41a, 41 for selecting the desired image control method such as
b, 41c are provided, and these selection members 41
Select the required image control method using a, 41b, and 41c.

The document 16 whose position on the document surface has been designated as described above is transferred onto the document table 26 with the document surface 18 facing the document placement surface 28 .

At this time, the photoreceptor 1 of the document surface image is placed on the document placement surface 28.
During exposure to 0, an orthogonal coordinate is formed by the X' axis and the Y' axis with the starting point 42 where the phase of the original platen 26 and the phase of the photoreceptor 1o match as the origin, and the original 16
The coordinate origin 4 on the position detection plate 36 for transferring the
The two end points of the original 16 that matched with the X axis and the Y axis are respectively set as the starting point 42. X' axis, Y'
By aligning with the axis, consistency between the coordinates of the position detection plate 36'' and the coordinates of the document table 26'' and phase consistency between the starting point 42 on the document table 26- and the photoreceptor 10 can be maintained. I can do it.

Next, the rectangular deposit area ACB specified by the above procedure
The copying operation in this embodiment will be explained by taking as an example the case where the document surface image corresponding to D is to be erased. The charger 14 has a width x corresponding to a rectangular area ACBD on the document surface.
The charge control means 34 controls the charging control means 34 so as to stop charging the photoreceptor 10 by corona discharge only during a length 7172 corresponding to the rectangular area ACED (1-) over the length 1x2. Next, the reflected image of the document surface 18 is sequentially exposed on the photoconductor 1Q by the fluorescent lamp 20, and an electrostatic latent image corresponding to the document surface image is formed on the photoconductor 10.
However, as mentioned above, no charge is applied to the photoreceptor portion corresponding to the rectangular area ACBD, regardless of the document surface image, and therefore, after development by the developer 24, a developed image is formed. However, toner does not adhere, and as a result, a developed image is formed in which the document surface image corresponding to the rectangular area ACBD is erased.

In the above example, the portion corresponding to the rectangular area ACBD is erased, but the initial charge can be applied to the photoreceptor 1o by reducing the corona discharge current from the charger 14 by the required amount by the charge control means 34. It is possible to reduce the amount of residual charge in the portion corresponding to the rectangular area ACBD while keeping the exposure state of the reflected image on the document surface 18 the same. As a result, the density of the developed image formed by the developing device 24 can be lowered. For example, when copying a document having background density only within the rectangular area ACBD, the so-called so-called Fog can be selectively removed.

Here, in the conventional configuration, the charger 14 is configured to generate a single corona discharge across the width direction of the photoreceptor 10. However, it is difficult to control the corona eccentricity only in a section of the required width x1x2 of the document surface in the width direction of the document surface 18, that is, in the X-axis direction, as shown in FIG. In this embodiment, the charger 14 is used.

As shown in FIG. 4, a plurality of charging elements 44 of a size that can divide the surface of the photoreceptor into a plurality of charging areas are arranged, and these charging elements 44 are used to charge the photoreceptor 1.
By applying a charge to each charged area of Q and applying a surface potential, it is possible to control the initial charge amount of a portion of the photoreceptor 1o corresponding to an arbitrary area on the document surface 18. I have to.

Further, by configuring the charging element 44 so that an overlapping portion is formed at the end portion 46 of the charged region to which charges are applied by adjacent charging elements, charges are generated on the photoreceptor 1o. It is possible to prevent areas from being left uninspected.

With this configuration, it is possible to control the amount of charge applied by the charging element 44 to each of the plurality of charged areas, and therefore, the image density can be adjusted for each unit area, using the charged area as a unit. It becomes possible to control. Therefore, in the above embodiment, the area to be subjected to image control is described as being rectangular, but similar image control can be performed on an area of any desired shape by dividing the photoreceptor surface into charged areas.

Effects of the Invention As described above, the present invention includes, in addition to the charging means in the conventional Nariko photographic apparatus, charge control means for controlling the operation of applying charges to the photoreceptor by the charging means, thereby controlling the surface potential of the photoreceptor. By making it possible to adjust the charge applied to the photoreceptor according to the specified position on the document surface, and by providing a position detection means for detecting a specified position on the document surface, the charge applied to the photoreceptor can be adjusted. This makes it possible to control the density of a copied image according to the specified position. Furthermore, the charging means is configured with a plurality of charging element means large enough to divide the surface of the photoreceptor into a plurality of charging regions, and by applying a charge to each charging region,
Image control using this charged area as one unit becomes possible.

Here, an example of a specific effect will be explained with reference to FIG. 5. FIG. 6(a) shows the surface of a document to be copied, and an image is written on the document surface 18 in a diagonally shaded area surrounded by a solid line. If only the part indicated by the broken line is the necessary image to be copied, by using the Nariko photographic device of the present invention, only the necessary part is left as shown in FIG. 6(b), and the other parts are It is possible to form a copy image in which unnecessary portions of the image are deleted, and a beautiful and easy-to-see copy image can be obtained. Of course, it goes without saying that the shape of the required image area may be arbitrary.

[Brief explanation of drawings]

FIG. 1 is a schematic front view of main parts showing an example of a conventional electrophotographic apparatus, FIG. 2 is a perspective view of main parts showing an embodiment of the Nariko photographic apparatus of the present invention, and FIG. 3 is an area on a document surface. FIG. 4 is a front view showing an embodiment of the charging means used in the electrophotographic apparatus of the present invention, and FIGS. 5(a) and (b) illustrate an example of the effects of the present invention. FIG. 3 is a perspective view showing the correspondence between the original surface and the copy surface of the paper. 1o...- Photoreceptor, 14... Charger, 16...
...manuscript, 18...manuscript surface, 2o...river...
Fluorescent lamp, 22...Optical fiber, 24
...Developer, 25...Transfer charger, 26.
...Document stand, 28...Document placement surface, 34-...
...Charging control means, 36-...Position detection plate, 38
...Indication pen, 4o...Origin, 41a. 41b, 41C... selection member, 42... starting point, 44... charging element, 46... end. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5

Claims (3)

[Claims] (1) A position detecting means for detecting a specified position on the document surface, a photoreceptor on which an image of the document surface is formed and exposed, and a means for applying a surface potential to the exposed surface of the photoreceptor. The charging means includes a charging means and a charge control means for controlling the operation of the charging means in accordance with a signal of the position on the document surface detected by the position detecting means, and the charge control means is provided on the surface of the photoreceptor by the charging means. An electrophotographic apparatus characterized in that a surface potential can be changed in accordance with a signal of a position on a document surface detected by the position detecting means. (2) The charging means for applying a surface potential on the photoreceptor surface is constituted by a plurality of charging element means having a size that can divide the photoreceptor surface into a plurality of charging areas, and the plurality of charging elements The electrophotographic apparatus according to claim 0, wherein a surface potential can be applied to each charged area of the photoreceptor by a means. (3) Each of the plurality of charging element means that divides the surface of the photoreceptor into a plurality of charging regions is configured such that an overlapping portion occurs between the charging regions to which surface potential is applied by adjacent charging element means. An electrophotographic apparatus according to claim (2), characterized in that: