JPS60247656A - Paper feeder - Google Patents

Abstract

PURPOSE:To restrain waste of papers to the minimum limit in case of double paper feed and to enhance efficiency in copying operation by ejecting the paper having one side not copied due to double feed out of a copying machine, without exposing a photosensitive drum by using an optical system to transfer a toner image to this paper in the second copying stage. CONSTITUTION:An image sensor 9 is arranged at a proper position on the conveyance route 8 from a both side tray 2 to the transfer section 4 of the photosensitive drum 1, and it is electrically connected through a controller 10 arranged at a proper position in the main body of a machine to the driving section 11 of the optical system to detect a paper having one side not copied due to double paper feed occurring when papers are fed from a paper feed tray 3 to the transfer section 4, from among the one side-copied papers fed from the both side tray 2 to the section 4. The driving section 11 of the optical system is temporarily stopped through the controller 10 with the detection signal to stop exposure to the photosensitive drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a paper feeding device for an electrophotographic copying machine or the like capable of automatic double-sided copying.

(Prior Art) A conventional electrophotographic copying machine capable of automatic double-sided copying has two upper and lower double-sided trays 2 and a paper feed tray 3 on one outer periphery of a photoreceptor drum 1 in the machine, as shown in FIG. 1, for example. Provided in steps,
A paper transport path 5.5' is provided from the paper feed tray 3 to the paper output tray outside the machine via the transfer section 4 of the photoreceptor drum 1, and the transport path 5' travels outward at an appropriate location to transfer both sides of the paper. A conveyance path 6 leading to the tray 2 is provided, and a paper guide 7 is disposed at the branching point, while a conveyance path 8 is provided from the double-sided tray 2 to the transfer section 4 of the photoreceptor drum 1. The paper 9 stored in the tray 3 is fed into the transfer section 4 of the photoreceptor drum 11, where the toner image formed on the surface of the photoreceptor drum 1 is transferred onto one side of the paper, and the toner image formed on the surface of the photoreceptor drum 1 is transferred by the fixing device. After fixing the film, it is guided in the direction of the conveyance path 6 by the use guide 7 and stored in the double-sided tray 2, and then transferred from the double-sided tray 2 through the conveyance path 8 to the photosensitive drum 1. The toner image is transferred to the remaining one side of the sheet, and after the image is fixed by a fixing device, it is discharged to a paper output tray outside the machine via a conveyance path 5'. It had been. However, electrophotographic copying machines with this type of configuration were not equipped with a means to detect double feeding of paper, so detection was delayed and page errors occurred in the final copies. This has disadvantages in that not only is paper wasted, but also a time loss is caused by having to copy again from the page of the paper where the single double feed occurred.

(Object of the Invention) The present invention has been made in order to eliminate the drawbacks of the conventional electrophotographic copying machines capable of automatic double-sided copying.
If double feeding of paper occurs when making double-sided copies,
After one-sided copying is completed, the double feed is discovered while copying the remaining one side, and the optical system automatically prevents the exposure process for the paper on which an image is not formed on one side due to the double feed. It is an object of the present invention to provide a paper feeding device that can minimize the damage caused during copying operations caused by double feeding of paper.

(Structure of the Invention) For this purpose, the present invention provides an image detection sensor installed at an appropriate location on the paper conveyance path from the double-sided tray disposed outside one side of the photoreceptor drum in the main body of a machine such as an electrophotographic copying machine to the transfer section of the photoreceptor drum. Place the sensor through the controller, etc. to expose the lamp and mirror.

The sensor is connected to a driving section of an optical system consisting of a lens, etc., and when the sensor detects that paper on which no image is formed is sent from the double-sided tray to the transfer section of the photoreceptor drum, the detection signal is sent. is sent to the controller, and the controller issues a command to the drive section of the optical system to temporarily stop the exposure process, so that the paper is not exposed to light.

(Example) The present invention will be described in detail below based on an example shown in the drawings.

2 is a schematic configuration diagram showing an embodiment of the paper feeding device of the present invention.

In the figure, a double-sided tray 2 and a paper feed tray 3 are provided in upper and lower two stages on one outer side of a photoreceptor drum 1 in the main body of a machine such as an electrophotographic copying machine. The paper passes through the paper output tray outside the machine and passes through the paper transport path 5.
．． A conveyance path 6 is provided to the double-sided tray 2 by branching the conveyance path 5' at an appropriate point, and a paper guide 7 is disposed at the branching point. The provision of the transport path 8 across the transfer section 4K is the same as in the conventional art. On the other hand, an image sensor 9 is disposed at an appropriate position on the conveyance path 8 from the double-sided tray 2 to the transfer section 4 of the photoreceptor drum l, and the sensor 9 is provided with an optical The sensor 9 is electrically connected to the drive section 11 of the system, so that the sensor 9 transfers the paper from the paper feed tray 2 to the transfer section 4 of the photoconductor drum 1 during the sheet feeding from the double-sided tray 2 to the transfer section 4 of the photoconductor drum 1. When a sheet of paper with no image formed on one side is detected due to double feeding that occurs when feeding the sheet of paper, the controller 10 temporarily stops the drive unit 11 of the optical system based on the detection signal and exposes the sheet. Avoid doing this.

The present invention is constructed as described above. And now,
If the sheets are fed from the paper feed tray 3 to the transfer section 4 of the photoreceptor drum 1 in a normal state, one side of these sheets will be covered by the transfer section 4 of the photoreceptor drum 1. The toner image formed on the surface is transferred and stored upward in the duplex tray 2 through the conveyance path 6, and from the tray 2 is transferred to the transfer section 4 of the photoreceptor drum l in order to copy the remaining one side. When I was sent there.

There is no problem since the image is detected by an image detection sensor placed at a suitable position on the conveyance path 8, but the paper feed tray 3
If the sheets fed from the transfer section 4 of the photoreceptor drum 1 for the first one-sided copying are multi-fed, the toner image is transferred only to the upper sheet in the transfer section 4 of these sheets. When the paper is stored in the duplex tray 2 as it is and then sent to the transfer section 4 of the photosensitive drum 1 for copying the remaining one side, the image detection sensor detects this double feed as if there is no image. This is detected, and in response to the signal, the controller temporarily stops the exposure of the optical system and stops the exposure of the paper without the image, so the paper passes through the transport path 5' with the image on both sides. While the paper is ejected onto the paper ejection tray outside the machine, the exposure process of the optical system is stopped only for the paper on which a copy was not formed on one side due to the double feeding, and from then on, the paper continues as usual. Since the exposure is carried out, the pages to be copied are made in an orderly manner, except for the paper on which no image was formed on one side due to the above-mentioned double feeding, so that the pages to be copied are not distorted.

(Effects of the Invention) The present invention is configured and operates as described above.
When making double-sided copies, the photosensitive drum 1 is removed from the paper feed tray 3.
When feeding sheets to the transfer unit 4, even if double feeding occurs, the image of one side is transferred to the upper sheet of the double fed paper in the transfer unit 4, and the image of the one side is Since it is the lower paper that is not transferred, the paper that has not been transferred on one side is not exposed to the optical system when transferring the remaining one side, and is placed on the paper output tray outside the machine. Therefore, other sheets other than the paper in question can be copied on one side in page order, which minimizes wastage of paper in the event of double feeding. This double-sided copying process is extremely efficient since there is no need to copy again from the part of the paper that caused the single double feed, unlike the conventional copying process when double feeding occurs. It has the effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a paper feeding device in a conventional electrophotographic copying machine, etc., and FIG. 2 is a schematic configuration diagram showing an embodiment of the paper feeding device in an electrophotographic copying machine, etc. of the present invention. In the figure, 1...photosensitive drum, 2...double-sided tray, 3...
...Paper feed tray, 4...Transfer section, 5.5', 6...
Paper transport path. 7...Paper guide, 8...Paper conveyance path, 9...
Image detection sensor, 10... Controller, 11...
・Optical system drive unit. Figure 2

Claims (1)

[Claims] A double-sided tray and a paper feed tray are arranged at appropriate locations on one outside of the photoreceptor drum, etc. in the machine main body, and the paper fed from the paper feed tray is transferred to the transfer section of the photoreceptor drum. Automatic double-sided copying is possible, in which after a single-sided copy is made, the paper is stored in the duplex tray, and the paper is fed from the duplex tray to a transfer section of a photoreceptor drum to copy the remaining one-sided side. In an electrophotographic copying machine or the like, an image detection sensor is disposed at an appropriate position on the paper conveyance path from the double-sided tray to the transfer section of the photoreceptor. It is connected to the drive unit of the optical system, which consists of an exposure lamp, mirrors, lenses, etc. inside the machine, via a controller. When one of the sheets fed from the double-sided tray to the transfer section of the photoreceptor drum is detected to have no image, the driving of the optical system is stopped in response to that signal, and the sheet is not exposed to light. A paper feeding device characterized by: