JPH02689B2 - - Google Patents

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, an electrophotographic machine is known which has a plurality of paper feed units and is 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 to practical use. In other words, in order to optically detect the size of a document, it has been considered to simply differentiate the size of the document by changing the reflectance of the document and the document cover, but in reality, since various types of document 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. It was hot. For this reason, there are cases where recording paper of a size suitable for the original document size cannot be reliably fed due to forgetting to specify the size, and it is necessary to perform image formation again, and this operation is not only troublesome but also extremely wasteful. There is a problem.

The present invention was made based on the above circumstances, and
The purpose is to provide an electrophotographic device that can reliably detect the original size and automatically feed recording paper of a size that matches the original size based on the detection result. It is.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a document cover having a spectral reflectance substantially corresponding to the spectral sensitivity wavelength range of an electrophotographic photoreceptor, 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 present invention is configured to include a paper feeding means for feeding recording paper of a desired 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 original size regardless of the type, and based on this detection result, it is possible to automatically feed recording paper of the size that matches the original size from among multiple paper sources, allowing for recording of different sizes. It is possible to reliably prevent paper from being fed incorrectly. Furthermore, since a desired size can be specified regardless of the detection result by the document size detection means, it is also possible to feed recording paper that is different in size from the document size.

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

For example, a photoreceptor in which the photoconductive layer is made of selenium has sensitivity on the short wavelength side of 0.6 μm or less, as shown by the solid line in FIG. However, 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. That is, as blue, ultramarine,
Cobalt blue, copper phthalocyanine blue, oil blue. Chrome green as green, copper phthalocyanine green. The red colors are cadmium red, mercury red, and pyrazone red. Note that two or more of these colorants can also be mixed to adjust the color.

Further, the spectral reflectance of a generally used white original is shown by a solid line. In this way, the original exhibits substantially uniform reflection characteristics from the visible region to the near infrared.

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 constructed 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. A document 3 having the above-mentioned reflection characteristics is provided between the document table 1 and the document cover 2.
intervene. A photocoupler 4, which is a detection element, is provided along the document table so as to be able to move back and forth. The photocoupler 4 is, for example, GaP,
Light-emitting diodes such as GaAs and GaAsP are easy to use because they emit red and green light, but the light-emitting element 4a, which can be an incandescent lamp, and CdS, Se, SPD
Light receiving element 4b such as (silicon photodiode)
It consists of Further, if necessary, a filter having a desired spectral transmittance may be used in combination. The wavelength sensitivity range of this photocoupler 4 is as shown by the solid line in FIG. 1, and the wavelength sensitivity range of the photocoupler 4 is used in which the solid line indicating the reflection characteristics of the document cover 2 is not reflected. However, for the solid line representing the reflection characteristics of the original 3, it covers a sufficiently sensitive wavelength range.

Although not shown in the drawings, it goes without saying that the electronic copying machine is provided with a paper feeding device that accommodates recording paper of a plurality of sizes, and is also provided with an exposure device and other known copying devices.

When the print button 5 is pressed as shown in FIG. 4, the copying process control circuit 6 is activated, and the photocoupler 4 constituting the original detection circuit moves forward to optically scan the original table. Then, as shown in FIG. 3, the signal output from the photocoupler 4 changes greatly between a certain part of the document 3 from l 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 area from l to m as the density detection area of the original 3, necessary exposure control can be performed. The output duration of the photocoupler 4 is measured by a pulse counter, and as shown in FIG. 4, the size of the document 3 is detected from the detection time by the document size detection circuit 7 as a document size detection means, and the size of the document 3 is set to a preset recording paper size. Comparison and verification are performed in a comparison and verification circuit 9 together with a detection circuit 8 . Note that, as is clear from the principle, this size detection is performed in exactly the same way even when the operator operates the document cover 2 with it open. And this circuit 9
A recording paper size selection signal is sent to a paper feeding device drive circuit 10 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 the AND is performed, the paper feed device drive circuit 10 feeds the recording paper of the selected size. In addition, if a desired size of recording paper is to be used regardless of the document 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 when the photocoupler 4 moves back and forth, and the document 3 may be exposed when it moves back and forth.

Further, in the above embodiment, the photocoupler 4 is used for both the identification of the original 3 and the density detection, but the invention is not limited to this. Dedicated detection elements may be provided for each, and these processes can be performed using various conventionally known methods. electronic processing is possible.

Furthermore, in the above embodiments, selenium was applied to the photoreceptor used, but the invention is not limited to this.
Other types of photoreceptors may be used, and the same effect as in the above embodiment can be obtained by setting the spectral reflectance of the document cover 2 and the wavelength used by the detection element according to the spectral sensitivity characteristics. can get. 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 invention.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to detect the document size and automatically feed recording paper of a size that matches the document size from among a plurality of paper feed units based on the detection result. Therefore, it is possible to reliably prevent recording paper of different sizes from being fed by mistake. Furthermore, since it is possible to specify a desired size of recording paper 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]

Figure 1 is a reflection characteristic diagram to explain the basic principle of document identification, Figure 2 is a sectional view of the main parts of an electronic copying machine, Figure 3 is a signal output diagram, and Figure 4 is an electrical block diagram. be. 2... Original cover, 3... Original, 7... Original size detection means (original size detection circuit), 10...
Paper feeding means (paper feeding device drive circuit), 12... designation means (manual size selection circuit).

Claims (1)

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