JPS61282858A - Controlling method for copying operation - Google Patents

Abstract

PURPOSE:To prevent a black stripe and a black frame copy from being formed by stopping the feeding of transfer paper and displaying a no paper feeding state when the size of transfer paper is larger than the size of an original image on a photosensitive body. CONSTITUTION:A copy magnification signal, an original size signal, a transfer size signal, and a pressure plate ON-OFF signal are fetched to a CPU 1. The CPU 1 supplies an ON-OFF signal to a transfer paper feeding part 2 through a paper feed driving roller 3 on the basis of those signals. Further, a display device 4 is connected to the CPU 1. The CPU 1 compares the size of transfer paper with the size of an original image formed on the photosensitive body to feed transfer paper when the transfer original size is smaller than the original image size, or stop the feeding of transfer paper and also display the no paper feeding state on the display devide 4 when the transfer paper size is larger than the original image size.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a copying operation control method capable of preventing the occurrence of black bands and black border copies in a dry type electrophotographic copying apparatus.

BACKGROUND TECHNOLOGY In general, dry type electrophotographic copying apparatuses perform charging, exposure, erasing, development, static elimination before transfer, transfer, static elimination before cleaning,
Copying is performed through an image creation process of cleaning and post-cleaning static elimination. In other words, the photoconductor is first uniformly charged over the entire surface by a charger to form a solid latent image, which is adjusted according to the density of the document by exposing the document image, and an electrostatic charge with the same content as the document image is placed on the photoconductor. A latent image is formed. The next erase process involves various processes such as leading edge erase, trailing edge erase, and site erase, but conventionally, regardless of the original size, the transfer paper size is detected by the size detection means attached to the cassette. This transfer paper size is used to optically erase unnecessary electrostatic latent images on the photoreceptor, thereby preventing copy defects due to unnecessary transferred images outside the frame in the transfer process.

In such a process, a problem arises when the pressure plate is not set with respect to the document set on the document table (contact glass). In other words, when the pressure plate is not set, an electrostatic latent image is formed on the photoconductor by the light irradiated by the optical system depending on the density of the document surface, but in areas other than the original area, the pressure plate is Since there is no reflected light, the irradiated light passes through the document table, and the potential of the entire solid latent image on the corresponding photoconductor surface remains at a high potential because it does not receive reflected light.Therefore, in the next erase process, If the erase width is determined based on the transfer paper size as in the past, if the original is A4 or B5 size and the transfer paper is 84 or A3 size, the electrostatic latent image on the photoreceptor other than the original size will not be developed. Since this is transferred to the transfer paper, unnecessary black solids, black bands, black frames, etc. are generated in the copy due to completely black solid development outside the original area.

The copy quality will be poor.

OBJECTS The present invention has been made in view of the above points, and an object of the present invention is to provide a copying operation control method that can eliminate the occurrence of defective copies such as black bands and borders using a simple method.

Structure In order to achieve the above object, the present invention provides an electrophotographic copying apparatus equipped with means for detecting document size, means for setting copying magnification, and means for detecting transfer paper size. Compare the size of the original image to be formed, and when the transfer paper size is smaller than the original image size, feed the transfer paper, and when the transfer paper size is larger than the original image size, do not feed the transfer paper. The feature is that the unfed paper is displayed.

Hereinafter, one embodiment of the present invention will be described based on the drawings. This embodiment focuses on the fact that black band copying occurs when the transfer paper size is larger than the image, and focuses on not only the transfer paper size but also
It compares the size relationship with the original image size on the photoconductor calculated based on the original size and copying magnification, and if the transfer paper size is small, the transfer paper is fed and the copy operation is performed normally, but in the opposite case That is, when the transfer paper size is larger than the original image size, the copying operation is not executed by not feeding the transfer paper.

In order to control such operations, a control circuit is constructed as shown in FIG. That is, the CPU 1 is the main control unit, and the CPU 1 receives signals such as a copying magnification signal such as equal magnification, enlargement, reduction, etc., an original size signal, a transfer paper size signal, and a pressure plate ON/OFF signal. Based on these signals, the CPU gives an ON-OFF signal to the transfer paper feed section 2 via the paper feed drive controller 3. A display device 4 is also connected to this CPUI. Further, the ON-OFF side of the pressure plate 5 is detected by a sensor 7 provided on the copying machine main body 6 and an actuator 8 provided on the pressure plate 5, as shown in FIG.

Here, the transfer paper size can be determined using a known size detection means provided in the cassette. on the other hand.

The document size can be detected by, for example, providing a plurality of reflective sensors or the like on the lower surface of the contact glass on which the document is set, at respective size positions. The copy magnification is set by operating the operation panel.

The CPU performs calculations based on these document sizes and copying magnification to determine the document image size on the photoreceptor. These processes are performed when it is determined that the pressure plate 5 is not set, as shown in the flowchart of FIG. Then, the size of the transfer paper and the size of the original image on the photoreceptor are compared.

In this comparison, if the transfer paper size is smaller, C
The PUI outputs a paper feed ON signal to the paper feed drive controller 3 to operate the transfer paper feed section 2.

In other words, the transfer paper is fed and the copying operation is performed normally. In this copying operation, an electrostatic latent image is formed on the photoreceptor in a size larger than the size of the transfer paper, but a developed image larger than the size of the transfer paper is not copied onto the transfer paper. In any case.

On the other hand, since the transfer paper size is regulated, defective copies such as black bands and black border copies will not occur.

If the original image size is smaller than the transfer paper size,
An OFF signal is output from the CPU to the paper feed drive controller 3, and the transfer paper feed section 2 is controlled not to perform a paper feeding operation, so that the transfer paper is not fed.

Due to this non-feeding of transfer paper, the copying operation will not be performed normally. In other words, in such a case, when the transfer paper is fed and a copy operation is performed, a solid black image is also formed around the original image visualized on the photoreceptor, and this is transferred to the transfer paper. However, according to this embodiment, the transfer paper is unfed, resulting in a black band copy or the like.

This prevents defective copies such as black belt copies from being made. At this point, the display device 4 provided on the operation panel displays that the transfer paper is not being fed, and the operator can know the cause of the error by looking at this display. Therefore, normal copying can be performed by taking countermeasures such as changing the size of the transfer paper or changing the copying magnification.

On the other hand, when the back plate 5 is set, as shown in the flowchart of FIG. 3, the size comparison control described above is all canceled, transfer paper is fed, and a copying operation is executed. With this pressure plate 5 set,
The area outside the original image area becomes blank due to the reflected light, and problems such as black band copying do not occur.

By the way, when the transfer paper size is larger than the original image size, the transfer paper will not be fed as described above, but even if the operator presses the release switch etc. based on the paper non-feeding indication, the transfer paper will not be fed. good. As a result of this cancellation operation, the display of unfed paper is turned off, indicating that the cancellation has been made. In the copying operation after this paper misfeed is cleared, the area of the developed image is controlled so that the developed image formed on the photoconductor is only the original image part, and the copying operation is performed. , to prevent black frame copies from occurring. This is the process after the paper failure is indicated in the flowchart of FIG.

Here, as a method that does not form a developed image outside the original image size, since the original image size is calculated in the CPUI, the eraser in the copying process is controlled using this original image size, and the electrostatic image outside the original image is This can be done by erasing a latent image. In addition, a charger may be used to control the uniform charging width of the photoreceptor to the document image size. By controlling the charging width of the photoreceptor by the charging charger, an electrostatic latent image and therefore a developed image are not formed in areas outside the document image that are not uniformly charged, regardless of the presence or absence of light, and this eliminates the possibility of erasing. This is because they are the same. As a means for this, charging wires for each size may be provided and selected. Alternatively, a method may be used in which the development width of the electrostatic latent image on the photoreceptor in the development process is controlled.In other words, by controlling the development width, even if the electrostatic latent image is formed, areas outside the document image that are not developed may be removed. This is because no toner is attached to the image, so it does not form a visible image, and it still has the same effect as erasing.

Effects As described above, the present invention considers not only the transfer paper size but also the original size and the original image size on the photoreceptor based on the copying magnification, and compares the two sizes to determine if the transfer paper size is smaller than the original image size. By feeding the transfer paper, defective copies such as black bands and black border copies will not be made on this transfer paper, and since the transfer paper is not fed when the transfer paper size is larger than the original image size, Copying operations that result in black bands, etc. will not be executed, and the display will indicate this transfer paper misfeed, allowing the operator to know that the error is due to an incorrect transfer paper size, and take necessary measures. can be taken.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram, FIG. 2 is a schematic side view, and FIG. 3 is a flow chart. Applicant Ricoh Co., Ltd.

Claims (1)

[Claims] In an electrophotographic copying apparatus equipped with a means for detecting the document size, a means for setting a copying magnification, and a means for detecting the transfer paper size, the transfer paper size and the document image size formed on the photoreceptor are compared, and the When the transfer paper size is smaller than the original image size, the transfer paper is fed, and when the transfer paper size is larger than the original image size, the transfer paper is not fed and the non-feeding is displayed. Copying operation control method.