JPS61281256A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To surely detect original size regardless of the kind of the original by using the light of the wavelength region of the low spectral reflectivity of an original cover having the spectral reflectivity corresponding to the wavelength region of the spectral sensitivity of an electrophotographic sensitive body to identify the original. CONSTITUTION:The original is identified by using the light of the wavelength region of the low spectral reflectivity of the original cover having the spectral reflectivity corresponding substantially to the wavelength region of the spectral sensitivity of the electrophotographic sensitive body. There is no inconvenience even if the light having no sensitivity to the photosensitive body out of the light reflected from the original cover does no longer exist and therefore the ill effect of the reflectivity change of the original cover on the photosensitive body can be prevented by approximating the spectral reflectivity of the original cover to the reflectivity of the photosensitive body as far as possible. For example, the photosensitive body of which the photoconductive layer is selenium has the sensitivity on the short wavelength side of <0.6mum as shown by a solid line A. A satisfactory result is therefore obtd. if the original cover having such spectral reflectivity as shown by, for example, a solid line B is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic apparatus capable of detecting, for example, the size of a document.

(Prior Art) Conventionally, electronic copying machines have been known that include a plurality of paper feed units and are configured to artificially specify a recording paper of a size that matches the original document size.

On the other hand, although automatic identification of document size has recently been promoted, it is currently unreliable and has not been put into practical use.

In other words, in order to optically detect the size of a document, the following method has been considered, in which the reflectance of the document and the document cover are made different to simply distinguish the size, but in reality, since a variety of documents are used, The reflectance was not constant and the reliability of detecting the document size was extremely low.

(Problem to be solved by the invention) As described above, in the past, the size of the original could not be detected automatically, and when feeding recording paper of a size that matched the original, it was necessary to specify the size manually. was there. For this reason, there are cases where recording paper of a size that matches the original size cannot be reliably fed due to forgetting to specify the size, etc., and image formation must be performed again.This operation is not only cumbersome but also extremely uneconomical. There are problems like this.

The present invention has been made based on the above circumstances, and its purpose is to be able to reliably detect the original size, and to automatically select recording paper of a size that matches the original size based on the detection result. The present invention aims to provide an electrophotographic device that can feed paper.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a document cover that substantially corresponds to the spectral sensitivity wavelength range of an electrophotographic photoreceptor and has a spectral reflectance of the following spectral reflectance. a document size detection means for detecting the document size by identifying the document using light in a wavelength region with low spectral reflectance; The apparatus is configured to include a paper feeding means for feeding recording paper of an appropriate size, and a specifying means for specifying a recording paper of a desired size regardless of the detection result by the document size detection means.

(Function) The present invention identifies the original by using light in a wavelength range in which the spectral reflectance of the original cover, which has a spectral reflectance substantially corresponding to the spectral sensitivity wavelength range of the electrophotographic photoreceptor, is low. It is possible to reliably detect the document size regardless of the type, and based on this detection result, it can automatically feed recording paper of a size that matches the document size from among multiple paper sources.
It is possible to reliably prevent recording paper of different sizes from being fed incorrectly. Furthermore, regardless of the detection result by the document size detection means, it is possible to specify a desired size and to feed recording paper different from the size of the companion document.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. First of all, even if some of the light reflected by the document cover to which the photoreceptor is not sensitive disappears, the above-mentioned problems will not occur, so by making the spectral reflectance of the document cover as close as possible to the reflectance of the photoreceptor, This makes it possible to prevent adverse effects on the photoreceptor due to changes in the reflectance of the document cover.

For example, when the photoconductive layer is selenium, the photoreceptor has a first
As shown by the solid line in the figure, there is sensitivity on the short wavelength side of 0.6 μm or less. Therefore, for example, a document cover having a spectral reflectance as shown by the solid line ■ may be used. The material used for this document cover is, for example, polyvinyl chloride, unsaturated polyester, polyurethane, silicone resin, or the like. Furthermore, the colorants shown above are selected by matching with these materials. In other words, the blue one, the group! , cobalt blue, copper phthalocyanine blue, oil blue. Chrome green, copper phthalocyanine green 6 as green color
Cadmium red and Mercury red are red.

It's Pyrazone Red. Note that two or more of these colorants can also be mixed to adjust the color.

In addition, the solid line indicates the spectral reflectance of a commonly used white original.
Indicated by In this way, the original exhibits substantially uniform reflection characteristics from the visible region to the near infrared region.

A photoreceptor, document cover, and document having such characteristics are used in a general electronic copying machine. The document mounting table of this electronic copying machine is as shown in FIG. That is, reference numeral 1 denotes a document table made of a transparent glass material, which is covered with a document cover 2 made of the above-mentioned material and having reflective properties. An original 3 having the above-mentioned reflection characteristics is interposed between the original table 1 and the original cover 2. Along this document mounting table, a seven-way Oto coupler 4, which is a detection element, is provided so as to be reciprocally movable. The photocoupler 4 is made of, for example, GaP, GaAs,
A light emitting diode such as GaAsP is easy to use because it can emit red or green light, but it is composed of a light emitting element 4&, which may be an incandescent lamp, and a light receiving element 4b such as CdS, Ss, SPD (silicon photodiode), etc. be done.

Further, if necessary, a filter having a desired spectral transmittance may be used in combination. The wavelength sensitivity region of this photocoupler 4 is the first
In the drawing, the solid line 0 indicates the reflection characteristic of the original cover 2, and the solid line 2 indicates the reflective bending area. However, for the solid line (■) indicating the reflection characteristics of original 3, the wavelength range in which it is sufficiently sensitive is covered.

Although not shown, it goes without saying that the electronic copying machine is provided with a paper feeding device for accommodating recording paper of a plurality of sizes, and is also provided with a one-light device and other well-known copying devices.

As shown in FIG. 4, by pressing the print/button 5, the copying process control circuit 6 is activated, and the photocoupler 4, which constitutes the original detection circuit, moves forward to illuminate the original placing table. Run and eat.

Then, as shown in FIG. 3, the signal output from the photocoupler 4 changes greatly between a certain part of the document 3 from t to m and other parts.

As a result, it is possible to optically recognize the distinction between the third portion of the document and the second portion of the document cover. Further, by extracting the period from t to m as the density detection area of the original 3, necessary exposure control can be performed. The duration of the output from the photocoupler 4 is measured by a pulse counter, and as shown in FIG.
The size of the recording paper is detected and preset, and a comparison and verification is performed in a comparison and verification circuit 9 together with a detection circuit 8 for the next recording paper size.

Note that, as is clear from the principle, when the operator presses the document cover 2
This size detection is performed in exactly the same way even when the device is operated with the device open. A recording paper size selection signal is then issued from this circuit 9 to a paper feeding device drive circuit 10 serving as a paper feeding means. On the other hand, the copying process control circuit 6 issues a signal to the paper feed timing control circuit 11, and when AND is executed, the paper feed device drive circuit 10 feeds the recording paper of the selected size. Also, regardless of the original size,
When using recording paper of a desired size, it is sufficient to switch to the manual size selection circuit 12 as a specifying means.

Note that the size and density of the original 3 may be detected during the reciprocating movement of the photocoupler 4, and exposure may be performed during the return movement.Also, in the above embodiment, the photocoupler 4 was used for both identification and density detection of the original 3. The present invention is not limited to this, and a dedicated detection element may be provided for each, and these processes can be performed by various conventionally known electronic processes.

Further, in the above embodiment, selenium was used as the photoconductor used, but the invention is not limited to this, and other types of photoconductors may also be used. By setting the spectral reflectance of , and setting the wavelength used by the detection element, the same effect as in the above embodiment can be obtained. Further, the number of detection elements is not limited, and if a plurality of detection elements are used, errors in measuring the density of the original can be reduced.

Various other modifications and applications are possible within the scope of the gist of the invention.

[Effects of the Invention] As explained above, according to the present invention, light in a wavelength range in which the spectral reflectance of a document cover having a spectral reflectance substantially corresponding to the spectral sensitivity wavelength range of an electrophotographic photoreceptor is low is used. The size of the original can be reliably detected regardless of the type of original, and based on the detection results, recording paper of a size that matches the size of the original is selected from among multiple paper sources. Since paper can be fed automatically, it is possible to reliably prevent recording paper of different sizes from being fed by mistake. Further, since recording paper of a desired size can be specified regardless of the detection result by the original size detection means, it is possible to feed recording paper of a different size from the original.

[Brief explanation of drawings]

Fig. 1 is the ninth reflection characteristic diagram explaining the basic principle of document identification, Fig. 2 is a sectional view of the main parts of the electronic copying machine, Fig. 3 is the same signal output diagram, and Fig. 4 is the same as the electric copying machine. This is a diagram. 2... Original cover, 3... Original, 7... Original size □ Detection means (original size detection circuit), 10... Paper feeding means (paper feeding device drive circuit), 1 j -... Specification means (manual size selection circuit). Applicant's representative Patent attorney Takehiko Suzue 61.
7. il 8 Commissioner of the Japan Patent Office Michibe Uga 1, Indication of the case Patent Application No. 1988-45959 2, Name of the invention electrophotographic device 3, Person making the amendment Relationship with the case Patent applicant (307) Toshiba Corporation 4 , Agent I June 24, 1986 6, Subject of amendment Contents of amendment B

Claims (1)

[Claims] A document cover having a spectral reflectance substantially corresponding to the spectral sensitivity wavelength range of the electrophotographic photoreceptor is provided, and the document size is determined by identifying the document using light in a wavelength region in which the spectral reflectance of the document cover is low. A document size detection means to detect, a paper feed means to feed recording paper of a suitable size from among a plurality of paper feed units based on the detection result by the document size detection means, and a detection result by the document size detection means. 1. An electrophotographic apparatus having a specifying means for specifying a desired size of recording paper regardless of the size of the recording paper.