JPS60247659A - Abnormal copy quality detection mechanism - Google Patents

Abstract

PURPOSE:To automatically stop a machine to prevent loss of copies from this time forth when an abnormal copy is detected, by connecting both of a sensor for detecting the image density of an original and a sensor for detecting the image density of a copy to the comparator, and connecting the comparator to the controller of the main motor of the main machine body. CONSTITUTION:The density, etc., of the image of an original placed on a platen glass 1 are detected with a sensor 2 installed at the lower part of the platen glass 1. Its signal is sent to the comparator 3, and the density, etc. of the image of a copying paper fixed with a fixing machine 6 and ejected out of the machine is detected with a sensor 8 installed on the conveyance route from the fixing machine 6 inside the copying machine to a paper ejection tray 7 located outside the machine. Its signal is sent to the comparator 3 and both detected densities, etc., are compared here. When abnormal points are found in high or low density, unevenness, in the copied image with respect to the original image, the signal of such an abnormal state is sent to the controller 10 to immediately stop the main motor 9 of the machine, and to suspend the copying operation from this time forth.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention compares an original image with a copy image during copying using an electrophotographic copying machine or the like.

This invention relates to an abnormal copy quality detection mechanism that stops the drive of a main motor of a machine when abnormalities such as darkness, lightness, and unevenness are found in a copy image.

(Prior Art) Conventional electrophotographic copying machines, etc., when making several sets of copies in a continuous copy mode, detect any abnormality in copy quality that occurs during the copying process, and make adjustments based on the detection. Because there was no way to stop the machine, copying continued automatically until the end, and if you noticed an abnormality when binding after finishing copying, you would have to copy the pages after the page where the abnormal copy occurred again. This has the drawback of causing unnecessary waste in terms of resources and work time.

(Object of the Invention) The present invention has been made in order to eliminate the drawbacks of the conventional electrophotographic copying machines, etc., when making several sets of copies in the continuous copy mode.

The object is to provide an abnormal copy quality detection mechanism that detects the copy quality, automatically stops one machine if an abnormality is detected after checking, and prevents loss of copies thereafter. It is.

(Structure of the Invention) To achieve this, the present invention disposes a sensor for detecting the image density of a document at an appropriate location inside the machine, under the platen glass of an electrophotographic copying machine, etc. A sensor that detects the image density of the copy paper is placed at an appropriate location on the paper conveyance path leading to the paper, and both sensors are connected to a comparator placed at an appropriate location inside the machine. By connecting to the sensor, the image of the original and the image of the copy are detected by the sensor, the signals are compared by the comparator, and when an abnormality occurs, the comparator issues a signal to that effect to the main motor controller. , the drive of the main motor is stopped to stop the copying operation.

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

The figure is a schematic configuration diagram showing an embodiment of the abnormal copy quality detection mechanism of the present invention.

In the figure, a detection sensor 2 for detecting an image of a document is placed at a suitable place inside the machine, below a platen glass 1 of an electrophotographic copying machine, etc., and the sensor 2 is connected to a comparator 3 placed at a suitable place inside the machine. put. On the other hand, photoreceptor drum 4 in the same machine
A detection sensor 8 for detecting the image density of the copy is located at an appropriate position between the fixing device 6 and the paper ejection tray 7 during the paper conveyance path from the transfer unit 5 to the paper ejection tray 7 outside the machine via the fixing device 6. The sensor 8 is also connected to the comparator 3. The comparator 3 is connected to the controller 10 of the main motor 9 of the machine, and is set so that the main motor 9 can be stopped depending on the input signal.

The present invention is constructed as described above. Next, its operation will be explained.

Assume that the machine is currently operating in continuous copy mode, and the exposure lamp of the optical system projects light onto the original 11 placed on the platen glass 1, and the reflected light is transmitted to the photoreceptor through mirrors, lenses, etc. The surface of the drum 40 is irradiated to form an electrostatic latent image on the surface. Then, the electrostatic latent image is developed by a developer 12 arranged around one outer circumference of the drum 1, and the developed image is transferred to a copy paper fed from a paper feeder 13 in a transfer section 5, while After the copy paper is fixed by the fixing device 6, it is discharged onto a paper discharge tray 7 outside the machine via paper discharge rollers 14, 14'. During this process, the density of the image of the original placed on the platen glass 1 is checked.

A detection sensor 2 provided at the bottom of the platen glass 1 detects the signal and sends the signal to a comparator 3.

A detection sensor installed in the paper conveyance path from the fixing device 6 inside the machine to the paper output tray 7 outside the machine detects the density of the image on the copy paper that has been fixed by the fixing device 6 and is discharged outside the machine. 8 and sends the signal to the comparator 3. The comparator 3 compares the density, etc. of the image on the original document with the density, etc. of the image on the copy paper. When an abnormality such as darkness, lightness, unevenness, etc. occurs in the image, K sends a signal to that effect to the controller 10 to immediately stop driving the main motor 9 of the machine and stop the subsequent copying operation.

(Effect of the invention) The present invention is constructed and used as described above,
A detection sensor 8 detects the image density, etc. of the copy paper on which the fixing has been completed, and this is detected by a comparator 3 on the platen glass 1, which is detected by a detection sensor disposed at the bottom of the platen glass 1.
K is designed to stop the main motor 9 and stop the copying process when an abnormality occurs by comparing the image density of the original 11 placed on top, even if it is in continuous copy mode. Even if an abnormality occurs in the copy quality of the copy paper when making several sets of copies, the damage to the copy paper at that time is limited to the paper itself, and the cause of the copy quality abnormality can be determined at this point. Since it is possible to remove the material and then continue the copying operation again, it is effective in saving resources and improving the efficiency of the copying operation.

[Brief explanation of the drawing]

The figure is a schematic diagram of an abnormal copy quality detection mechanism in an electrophotographic copying machine according to the present invention. In the figure, 1... platen glass, 2... document image density detection sensor, 3... comparator, 4... photoreceptor, 5...
... Transfer unit, 6... Fixing device, 7... Output tray, 8
... Copy paper image density detection sensor, 9... Main motor. 10...controller, xt...manuscript.

Claims (1)

[Scope of Claims] An image density detection sensor for a VcyX document is disposed at a suitable location inside the machine under a platen glass in an electrophotographic copying machine, and a paper conveyance path from a fixing device inside the machine to a paper output tray outside the machine is provided. □ Image density detection sensors are placed on the copy paper at appropriate locations, and a comparator compares the image density, etc. of the original and the image density, etc. of the copy detected by these sensors, and when an abnormality is discovered, the signal is An abnormal copy quality detection mechanism characterized in that the abnormal copy quality is sent to a main Tanabata controller to stop the drive of the motor.