JPS5974575A - Detection for separation failure of transfer paper of copying machine - Google Patents

Abstract

PURPOSE:To prevent the malfunction that a separation failure is detected though a transfer paper is separated, by utilizing a ratio of the quantity of reflected light of the surface of a photosensitive drum to that of the transfer paper to detect the separation failure of the transfer paper during the copy operation. CONSTITUTION:A reflected light quantity detector 11 is arranged to face a photosensitive drum 1 in a transfer paper separating part; and if the separation failure occurs, an output voltage V1 of a phototransistor 11b is higher than the hold voltage of a capacitor 23c when the front end part of the transfer paper is detected by the detector 11, and consequently, the output of a comparator 25 becomes H, and a transistor 26 is turned on, and a lamp 27 indicates the occurrence of the separation failure. In this case, the amplification factor of a non- inverting amplifier 22 is set to a value lower than the ratio of the quantity of reflected light of the surface of a photosensitive drum 1 to that of the transfer paper and is set to a value larger than the variation rate of the quantity of reflected light of the photosensitive drum 1, thereby detecting surely the separation failure of the transfer paper.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer paper separation failure detection method for an electrostatic transfer copying machine.

An electrostatic transfer type copying machine forms an electrostatic latent image on the surface of a rotating photoreceptor drum by exposing it to light reflected from a document, and transfers this electrostatic latent image with toner. The toner image is developed into a toner image, and the toner image is transferred to the transfer paper by bringing the transfer paper into close contact with the surface of the photoreceptor drum.The transfer paper is then separated from the photoreceptor drum, and this separated transfer paper is fixed. The data is configured to be transferred to the device.

In such copiers, a phenomenon occurs in which the transfer paper is not separated from the photoreceptor drum, so that the transfer paper enters the cleaner that removes toner from the surface of the photoreceptor drum, causing the cleaner and the photoreceptor to be separated. This caused damage to the drum.

Therefore, conventionally, a reflected light amount detector consisting of a light emitting element and a light receiving element is provided opposite to the photoreceptor drum surface, and when the amount of reflected light from the photoreceptor drum surface exceeds a predetermined reference level, the photoreceptor is detected. It is arranged to detect that the transfer paper is almost separated from the drum, that is, a separation failure.

In such a division failure detection method, it is necessary to set the reference level of the amount of reflected light between the amount of reflected light from the photoreceptor drum surface and the scene of reflection from the transfer paper, but the Since variations occur in the attachment state of the detector to the photoreceptor drum (the gap with the photoreceptor drum, the angle between the drum surface and the optical axis, etc.), the setting range is limited. Therefore, the types of transfer paper to which the above-described conventional method can be applied are limited, and there is still the inconvenience that separation failure is detected even though the transfer paper has been separated.

The purpose of the present invention is to separate transfer paper that is not easily affected by variations in the %Q of the reflected light amount detector and the mounting condition, and has a relatively small difference in reflection sight from the photoreceptor drum surface like the second original paper. To provide a transfer paper separation failure detection system for a copying machine which can surely detect failures and prevent malfunctions such as detecting separation failure even though transfer paper has been separated.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows a schematic configuration of a copying machine according to an embodiment of the method of the present invention. The photoreceptor drum 1 shown in the figure has a ridge uniformly charged by a charging charger 2, and a manuscript image obtained from an optical system (not shown) is exposed through a slit 3, whereby the surface of the photoreceptor drum 1 An electrostatic latent image corresponding to the original image is formed. This electrostatic latent image
υ is developed with the developer supplied to the developing electrode 5, and after υ excess developer is squeezed out by the squeeze roller 6, the process proceeds to the transfer step.

In the transfer section, a transfer paper PA is fed from a paper feed section (not shown) so as to be synchronized with the image on the photoreceptor drum 1, and the transfer paper PA is charged by the transfer charger 7. The image on the photosensitive drum 1 is transferred to.

The transfer sheet FA' on which the original image has been transferred is separated from the photosensitive drum 1 by a turn roller 8 and conveyed to a fixing section.

In the fixing section, the transfer paper PA' is pressed against the hot plate 101 by the pressure roller 9, and the original image is dried and collapsed into a transfer 1: PA', and then discharged outside the machine.

Further, the surface of the photosensitive drum 1 after the transfer process is cleaned by a cleaning roller 12 and a cleaning blade 13.
The paper is cleaned by cleaning, and is further uniformly neutralized by a static eliminating charger 14 in preparation for the next copying operation.

A reflected light amount detector 11 is disposed facing the photoreceptor drum 1 between the turn roller 8 and the cleaning roller 12, which are the separation portions of the transfer paper PA. As shown in FIG. 2, the reflected light amount detector 11 is composed of a light emitting diode lla for irradiating light onto the surface of the photosensitive drum 1 and a phototransistor llb for receiving the reflected light. The light-emitting diode lla is arranged so that its light-emitting axis forms a predetermined angle with respect to the surface of the photoreceptor drum 1, and the phototransistor llb converts the output light of the light-emitting diode 11 that falls on the surface of the photoreceptor drum 1. The light-receiving surface is arranged to face the surface of the photoreceptor drum 1 in order to receive diffusely reflected light without receiving specularly reflected light.

When there is nothing on the photoreceptor drum 1, the surface of the photoreceptor drum 1 is close to a mirror surface, so that the diffused reflection component of the light reflected from the surface of the photoreceptor drum 1 is very small. On the other hand, if separation failure occurs, the transfer paper PA will be located between the surface of the photosensitive drum 1 and the reflected light amount detector 11. Generally, the surface of the transfer paper PA is rough, so the diffused reflection component in this case is very large, and therefore the output of the phototransistor llb becomes large in this case. In the present invention, a failure in dividing the transferred paper is detected by utilizing the difference in the amount of the diffused reflection component.

FIG. 3 is a block diagram showing a transfer paper separation failure detection device according to an embodiment of the present invention. In the figure, the emitter of the phototransistor 11b of the reflected light amount detector 11 is grounded via a resistor 21 and connected to a non-inverting input terminal of a fourth angle 22a constituting a non-inverting amplifier 22.

The amplification factor A of the non-inverting amplifier 22 is given by the following equation (1), where the resistance values of the resistors 22b and 22c are ra and rb.

A=10-... (1) rb Therefore, the output ■6 of the non-inverting amplifier 22 is expressed by the following formula ID, assuming that the output of the phototransistor llb, that is, the pressure at the non-inverting input terminal of the fourth amplifier 22a is ■1. It will come like this.

V = V
3a,) It is composed of a range meter 23b, a capacitor 23c, and an operational amplifier 23d forming a voltage follower, and its output vc is applied to the + side input terminal of the controller 24 and one side input terminal of the comparator 25, respectively.

A voltage vcc is connected to one input terminal of the comparator 24 through a resistor a.
The voltage (2) formed by dividing the voltage by t and R2 is also applied to the + side input terminal of the comparator 25 as the terminal voltage of the resistor 21, that is, the phototransistor] 1. The output v1 of b is added to each.

Main body control unit 40i1: Controls the scanning display unit 41 and the copying drive unit 42 that drives the photosensitive drum, roller, each charger, string supply unit, etc. without providing a man-machine interface between the operator and the copying machine. If the transfer paper PA is in contact with the photosensitive drum 1, the reflected light f
i. Corresponds to the rotational position of the photoreceptor drum 1 when the detector 11 detects it, and the rotational position of the photoreceptor drum 1 when the reflected light amount detector 11 deposits the leading edge of the transfer paper PA if separation fails. Then, the logic level of the signal S, which is applied to the transistor 23b to determine the timing of separation failure detection, is set to rHJ.

When the logic level of this timing signal S1 is "L", that is, when the separation failure is not detected, the transistor 23b
is in the OFF state, and is therefore electrically biased by the output V of the FET 23aFi operational amplifier 22a to become conductive. As a result, the operational amplifier 22a with the capacitor 23c
The output V. The battery charges and discharges in a manner that follows.

As described above, since the operational amplifier 23d constitutes a voltage follower, its output pressure d is equal to the pressure across both ends of the capacitor 23c. Therefore, in this case normal pressure■.

is approximately the voltage V. From the relationship of equation 11) above, voltage ■ becomes equal to . is always larger than the voltage V1, which causes the output of the comparator 25 to be at the logic level rLJ.

When the logic level of the timing signal 81 becomes rHJ, the transistor 23b is turned on at this point and the FET 2
Since the pressure applied to the dart 3a is pulled to -voF, this FET 23a becomes in a cut-off state. This causes the capacitor 23c[id to have a pressure V at this point. , that is, a voltage that is A times the output 1 of the phototransistor llb corresponding to the amount of diffusely reflected light from the portion of the photosensitive drum 1 that is not in contact with the transfer paper PA is held.

If separation of the transfer paper PA fails, the leading edge of the transfer paper PA will be detected by the reflected light -+ttS output device 11 while the logic level of the timing signal S1 is rHJO, so that the phototransistor Ilb The output cylinder 7 pressure v1 becomes larger than the hold voltage of the capacitor 23c, so the output of the controller i and the regulator 25 reaches the logic level rHJ.
When the voltage rises, the transistor 26 is turned on and the lamp 27 indicates that the segmentation failure has occurred.At the same time, the transistor 28 is turned off, the power relay 29 is deenergized, and the photographing operation is stopped.

Therefore, the amplification factor A of the non-inverting amplifier 22 is set to be smaller than the ratio of light and sound reflected from the surface of the photoreceptor drum 1 and the transfer paper PA, and also larger than the fluctuation rate of the reflected scene of the photoreceptor drum 1. Particularly, failure in separation of the transfer paper PA can be reliably detected.

Further, separation failure detection of the Tenmanbou FA during copy standby can be performed as follows.

That is, the heavy pressure V formed by the resistors R and R2.

is the heavy pressure V when the reflected light amount detector 11 is detecting the transfer paper PA. Voltage V when the photosensitive drum 1 is detected by the reflected light amount detector 11 which is very small and does not come into contact with the transfer paper PA. Also set the value to a large value.

Therefore, if the power relay 29 is turned on without removing the transfer portion PA that has not been separated after a separation failure of the transfer paper PA occurs, the timing signal S1 at this time
Since the logic level of is rLJ, pressure ■.

and ■. is equal to Then, when the reflected light amount detector 11 detects the blade set PA that has not been removed, the voltage is set to ■.

But VR is also big, so comparator 2
4 rises to logic level rHJ, lamp 27
At the same time, the power relay 29 is deenergized.

It is also possible to apply the output signals of the conflators 24 and 25 to the main body control section 40 so that the main body control section 40 performs various controls after separation failure is detected.

As explained above, according to the present invention, during a copying operation, a failure in separation of the transfer paper is detected by using the ratio of the reflected light 1 from the photoreceptor drum surface and the reflected light 1 from the transfer paper. , it is possible to detect transfer paper separation failure without being affected by variations in the characteristics and mounting condition of the reflected light amount detector. Furthermore, it is also possible to detect transfer paper separation failure during copy standby. Furthermore, by optimally setting the above-mentioned scene ratio, the second
This has the effect that separation failure can be detected even in a transfer portion where the amount of reflected light is not much different from that on the surface of the photoreceptor drum, such as the set for original drawings.

[Brief explanation of drawings]

FIG. 1 is a partial diagram showing an outline of a copying machine according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing how a reflected light amount detector is attached to a photosensitive drum surface, and FIG. FIG. 1 is a block diagram showing a separation failure detection device according to an embodiment of the present invention. ■...Photosensitive drum, 8...Turn roller, 11...
...Reflection sight detector, 22...Non-inverting amplifier, 23...
・Sample hold circuit, 24.25... Comparator, 27... Lamp, 29... Power relay, 40
...Main body control section. Figure 1 Figure 2

Claims (1)

[Claims] A rotating photoreceptor drum, a developing section that develops the electrostatic latent image formed on the surface of the photoreceptor drum with toner, a transfer section that transfers the developed toner image onto transfer paper, and a photoreceptor that passes through the transfer section. In the transfer paper separation failure detection method of a copying machine, which is equipped with a separation section that separates the transferred transfer paper from the surface of the photoreceptor drum, and a cleaner section that cleans the surface of the photoreceptor drum that has passed through the separation section, A reflected light amount detector for detecting the amount of reflected light is disposed between the separation section and the cleaner section to face the photoreceptor drum surface, and during the copying operation, the reflected light of the portion of the photoreceptor drum surface that does not come into contact with the transfer paper, The ratio of the reflected light from the portion of the photoconductor drum surface that comes into contact with the transfer paper is equal to or higher than a predetermined value, and during copy standby, the amount of reflected light from the portion of the photoconductor drum surface that comes into contact with the transfer paper is a predetermined value. A transfer paper separation failure detection method for a copying machine is characterized in that a transfer paper separation failure detection method for a copying machine is characterized in that a transfer paper separation failure detection method for a copying machine is characterized in that a transfer paper separation failure detection method for a copying machine is determined when the transfer paper exceeds a value.