JPS60244984A - Separating device for paper or the like - Google Patents

Abstract

PURPOSE:To increase a response speed and reduce the sticking of toner by incorporating a separation claw made of a magnetic body in part of a magnetic path, and allowing the separation claw to contact and leave a rotary drum with an alternating magnetic field produced by a magnetic field generating means. CONSTITUTION:A form 2 is sent to the photosensitive drum 1 which turns as shown by an arrow, a latent image is transferred by a transfer electrifier 3, and the attracting force of the form 2 to the drum 1 is weakened by a separation electrifier 4. A separating belt 8 is arranged at the downstream side of the separation electrifier 4 between rollers 6 and 7 and the separating device 9 is installed above it. The separating device 9 consists of the separation claw 90 and alternating magnetic field generating means 91; the passing of the form 2 is detected 5a and 5b and a coil 9ab is fed with an alternating current a specific time later to allow the separation claw 90 to contact and leave the photosensitive drum 1 by rocking. Consequently, the form 2 is separated securely, sticking toner is shaken off, and the time when the separation claw 90 is pressed against the photosensitive drum 1 is shortened to prevent the drum 1 from being damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a paper sheet separating device used for separating transfer paper from a photosensitive drum of a copying machine.

<Prior art and its drawbacks> As a separating device used to separate transfer paper from a photoreceptor drum of an electrophotographic copying machine, a separation claw is arranged opposite to the rotational direction of the photoreceptor drum, and the tip of the separation claw is There is a structure that separates the transfer paper adhering to the drum surface.

However, if the separating claw is kept in contact with the drum surface for a long period of time, problems may occur, such as damaging the drum surface or adhering toner to the tip of the claw, staining the image. Therefore, Jikoko Sho 58-53547
As disclosed in Japanese Patent Application Publication No. 2003-110012, a device has been proposed in which the separation claw is moved in the width direction of the photoreceptor drum to prevent damage to the surface of the photoreceptor due to the separation claw. However, these devices have a very complex structure and large size, making it unavoidable to increase the cost of the entire copying machine.At the same time, since the separating claw remains in contact with the drum surface, it is impossible to completely prevent damage to the drum surface. There was an inconvenience that the toner could not be removed and the toner easily adhered to the tip of the separating claw.

<Object of the Invention> The object of the present invention is to apply vibration to a separation claw when separating paper sheets such as transfer paper from the drum surface, and to separate the paper sheets from the drum surface by the vibrating separation claw. ,
To provide a paper sheet separation device that prevents damage to the drum surface and toner adhesion to the tip of the separation claw, and that can be controlled with a simple mechanism, thereby simplifying the structure and realizing it at low cost. be.

<Structure and Effects of the Invention> The present invention supports a separating claw so as to be able to come into contact with and separate from the surface of a rotating drum, and a part thereof is made of a magnetic material, and furthermore, a magnetic field that makes this magnetic material part of a magnetic path is provided. A generating means and a means for generating an alternating magnetic field by turning on and off the magnetic field generating means alternately when separating the paper sheets are provided, and the paper sheets are separated from the rotating drum surface while vibrating the separating claw with the alternating magnetic field. It is characterized by

By configuring as described above, according to the present invention, paper sheets are separated from the rotating drum surface with the vibrating tip of the separating claw while applying vibration to the separating claw, thereby preventing scratches on the drum surface. Furthermore, since the separation claw itself vibrates, there is an advantage that toner adhesion to the separation claw is extremely reduced. Furthermore, since the separating claws are vibrated by the magnetic field generating means, the structure is very simple and there is an advantage that it can be realized at low cost.

<Embodiment> FIG. 1 is a diagram showing the main parts of an electrophotographic copying machine using a transfer paper separating device according to an embodiment of the present invention. A document image is formed on the surface of the document by a developing device. A transfer paper 2 is fed from the right side of the photosensitive drum 1 along a conveyance path. A transfer charger 3 and a separation charger 4 are disposed below the photoreceptor drum 1, and charge the image formed on the drum surface onto the transfer paper 2 sent toward the photoreceptor drums J, 1. The transfer charger 3 performs the transfer, and the separation charger 4 weakens the attraction force of the transfer paper 2 to the drum surface. Further, on the right side of the transfer charger 3, a transfer paper detection sensor 5 consisting of a light emitting element 5a and a light receiving element 5b is arranged, and the leading edge of the transfer paper 2 is detected by this detection sensor 5. The output of this transfer paper detection sensor is used to determine the on-timing of the separating device, which will be described later.

A peeling belt 8 is disposed on the left side of the separation charger 4 and is stretched between rollers 6 and 7. Further, above the peeling belt 8, a separating device 9 is arranged. The separating device 9 is composed of a separating claw 90 and a magnetic field generating means 91. As shown in FIG. 2, the separation claw 90 is made of a tapered magnetic material and is slightly bent downward along the dotted line 90C in the figure.

Further, a downwardly curved tongue piece 90a is integrally formed at the front. The magnetic field generating means 91 supports the rear end portion of the separating claw 90 and is attached to a bobbin 91b around which a coil is wound.
A magnetic pole 91c is attached to the upper surface of the core 91a, and a stopper 916 is attached to the lower surface of the rear end of the separating claw 90. magnetic pole 9
1G, the stopper 91d has its tip bent at a right angle and is arranged to face each other at a constant interval, and the separation claw 90 passes through the interval. As a result, the separating claw 90 made of a magnetic material can come into contact with and separate from the surface of the photoreceptor drum 1, and also constitutes a part of the magnetic path of the magnetic field generating means 91, and excites the coil to turn on the magnetic field generating means. Then, the separation claw 90 is attracted to the magnetic pole 91C and moves upward. Further, when the coil is de-energized and the magnetic field generating means is turned off, the separating claw 90, which has been attracted and attracted to the magnetic pole 91C, separates from the magnetic pole by its own elastic force and returns to its original position. At this time, the separation claw 90 stops at a position where it comes into contact with the tip of the stopper 91d. As a result, as shown in FIG. 1, when the magnetic field generating means 91 is off, the separating claw 90 is held at the position shown by the dotted line in the figure, and when the coil is excited and the magnetic field generating means is turned on, the separation claw 90 is held at the position shown by the solid line in the figure. Stop at. Separation claw 90 at the position of the solid line in the figure
If the positional relationship is determined so that the tip end 90b of the separating claw 90 is in contact with the photoreceptor drum surface, the separating claw 90 can be brought into contact with and separated from the photoreceptor drum surface by turning on and off the magnetic field generating means.

In the separation device having the above configuration, the magnetic field generating means 9
1 is turned on and off alternately to generate an alternating magnetic field, the separating claw 90 vibrates in synchronization with the alternating magnetic field, and the tip portion 90
b repeats the operation of coming into contact with and separating from the photoreceptor drum surface.

The output of the transfer paper detection sensor 5 is led to a control circuit (not shown). This control circuit is connected to the transfer paper detection sensor 5.
After a certain period of time has passed since detecting the leading edge of the transfer paper 2,
Its tip is the tip 90 of the separation claw 90. When the timing reaches b, the alternating magnetic field generating circuit is driven, the magnetic field generating means 91 is turned on and off alternately, and the separation claw 90 is vibrated.'Figure 4 shows a specific example of the alternating magnetic field generating circuit. It is a circuit diagram. In the figure, L is a coil wound around the bobbin 91b, and transistors Q2. Q3 controls the current flowing through this coil. A resistor R3 connected in series with the coil and a series circuit of resistor R2 and variable resistor R1 determine the magnitude of the coil current. The magnitude of the resistor R3 is set to be considerably smaller than the magnitude of the series combined resistance of the resistor R2 and the variable resistor R1. Transistor Q1 connected in parallel to variable resistor R1 is turned on and off by transistor Q4. When transistor Q1 is turned on, variable resistor R1 becomes short-circuited. A signal for generating an alternating magnetic field is input from a control circuit (not shown) to each input terminal of the transistors Q2 to Q4. A transfer paper detection sensor 5 is connected to the input terminal S3 of the transistor Q3.
When detects the leading edge of the transfer paper 2, a rectangular wave signal is input. A rectangular wave signal is input to the input terminal S2 of the transistor Q2 immediately before the leading end of the transfer paper 2 comes into contact with the leading end 90b of the separating claw 90. Further, a pulse equal to the generation period of the rectangular wave signal input to the terminal S2 is input to the input terminal S1 of the transistor 4 when it is desired to increase the vibration of the separation claw 90. In the above configuration, when the rectangular wave signal shown in No. 51F(a) is input to the terminal S3 at time tl, a current 11 flows intermittently from the resistor R2 side to the coil as shown in FIG. 5(d). A discontinuous current of magnitude 1 flows as shown in . Therefore, an alternating magnetic field is generated in the magnetic field generating means 91 at this point. However, the magnitude of the coil current at this time is such that the separation claw 90 is slightly vibrated. At time t2 immediately before the leading edge of the transfer paper 2 contacts the leading edge 90b of the separating claw 90, a signal is input to the input terminal S2 as shown in FIG. 5(b).
A rectangular wave signal as shown in is input. This rectangular wave signal is 180 degrees out of phase with the rectangular wave signal input to the input terminal S3. Therefore, a current 11 flows into the coil from the resistor R2 side, and a current 12 flows from the resistor R3 side.
As described above, since the resistor R3 is set to be considerably smaller than the series resistance of the resistor R2 and the variable resistor R1, the current 12 is -C larger than the current 1. Therefore, as shown in FIG. 5(d), from time t2 onwards, the magnitude of the coil current becomes 2, which is several times 1. Therefore, the alternating magnetic field formed in the magnetic field generating means 91 is amplified several times at the stage of time t2, and the vibration of the separating claw 90 also increases several times accordingly. This state continues until time t3. When the time t3 elapses, an alternating magnetic field is again generated only by the current 11, and when the time t4 comes, the excitation of the coil L is stopped. By controlling the coil L as described above, the vibration of the separation claw 90 increases between time t2 and t3, and at this point the leading edge of the transfer paper 2 is peeled off by the tip 90b of the separation claw 90. Become. Furthermore, time t
If the pulse signal shown in FIG. 5(c) is input to the input terminal 31 between 2 and t3, the variable resistor R1 is short-circuited by the transistor Q1, so that the current 11 increases. As a result, the coil current has a magnitude of 3 as shown in FIG. 5(d), making it possible to further increase the vibration of the separating claws 90 and to further ensure separation.

Next, the operation of the above separation device will be explained.

When the transfer paper 2 is conveyed from the right side, the leading edge of the transfer paper 2 is first detected by the transfer paper detection sensor 5.

At this time, the transfer charger 3 and the separation charger 4 are energized and start discharging. Furthermore, a rectangular wave signal shown in FIG. 5(a) is introduced to the input terminal S3 of the alternating magnetic field generating circuit. As a result, the leading edge of the transfer paper traveling along the surface of the photoreceptor drum 1 is
Since it is charged by the transfer charger 3, it is attracted to the surface of the drum 1. Moreover, the separation claw 90 is connected to the current j1 flowing into the coil.
It vibrates slightly. The attraction force of the portion attracted to the photoreceptor drum 1 is weakened by the subsequent charging by the separation charger 4, and the portion advances further forward. When the transfer paper 2 advances further and a certain period of time has elapsed since its leading edge was detected by the detection sensor 5, a rectangular wave signal shown in FIG. 5(b) is input to the input terminal S2 of the alternating magnetic field generation circuit. Then, the tip of the separating claw 90 vibrates greatly, causing the tip 90b to come into contact with and separate from the drum surface. At this time, the leading edge of the transfer paper 2 is pushed away downward along the lower surface of the separating claw 90, and when the leading edge of the banknote reaches the lower end of the tongue piece 90a, a rectangular wave signal is sent to the input terminal S2 of the alternating magnetic field generating circuit. input stops.

The separating claw 90 begins to vibrate slightly again after a while, and then the input of the rectangular wave signal to the input terminal S3 also stops, and the separating claw 90 returns to the position indicated by the dotted line in FIG. At this time, since the leading edge of the transfer paper has already been separated, the transfer paper 2 is then conveyed to the left by the peeling belt 8. The separated transfer paper is conveyed while being attracted to the peeling belt 8 by a suction fan (not shown). The transfer paper conveyance speed, the circumferential speed of the photoreceptor drum l, and the conveyance speed of the separation heald 8 are driven to be substantially synchronized by a known method, but the separation belt 8 is designed to prevent the transfer paper from curling toward the separation claw side. 0.6
The speed has been increased by about %. Through the above-described operations, the transfer paper 2 is reliably separated from the photosensitive drum surface by the separating device W9.

In the above embodiment, when the separation claw 90 is vibrated greatly, the tip of the separation claw 90 comes into contact with or separates from the photoreceptor drum surface, but the magnitude of the current 41, 12, etc. should be determined appropriately. The thickness of the transfer paper is -(10~
20 μm) The separation claw 90 can be vibrated around the floating position. In this way, the transfer paper can be separated very smoothly and reliably. Furthermore, since the separating claw is slightly vibrated for a while after the leading edge of the transfer paper is separated, the vibration allows the leading edge of the transfer paper to move smoothly in the direction of the peeling heald along the curved surface of the tongue piece 90a. Can be moved. Furthermore, when the leading edge of the transfer paper passes over the curved surface of the tongue piece 90a, the entire separating claw is vibrating, so the scratch-like image disturbance caused by the leading edge 90b is almost eliminated compared to when the separating claw is stopped.

The separating claw 90 may have a shape as shown in FIG. 3, and the entire magnetic field generating means 91 may have a configuration as shown in FIG. 6. In the figure, a magnetic field generating means 91 is attached to a rear end upper surface of a separation claw 90 with a coil 91e arranged perpendicularly to the traveling direction of the transfer paper 2, magnetic poles 91f and 91g, and arranged opposite to the magnetic poles 91f and 91g. It is composed of a magnetic material 91h. When the coil 91e is energized, the magnetic body 91h is attracted to the magnetic poles 91f and 91g, and the separation claw 90 made of an elastic body moves upward. When the electricity supply is stopped, the elastic body 90 returns to its original position due to its own weight. Furthermore, the tip of the separating claw 90 may be coated with Teflon or the like. By applying such a coating, toner adhesion to the separating claw can be extremely reduced.

By configuring the separating device as shown in FIGS. 1 to 6 above, the number of components can be extremely reduced, and the only movable part is the separating claw, which has the advantage of increasing the response speed. Furthermore, since the separation claw vibrates, toner adhesion to the separation claw is extremely reduced, and the phenomenon of image scratching can be almost eliminated.

Furthermore, damage to the photoreceptor can be almost eliminated.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main parts of an electrophotographic copying machine using a transfer paper separating device according to an embodiment of the present invention. Also, Figure 2,
Fig. 3 is a diagram showing another example of the separation claw used in the separation device, Fig. 4 is a circuit diagram of the alternating magnetic field generation circuit used in the separation device, and Fig. 5 is a circuit diagram of the alternating magnetic field generation circuit used in the separation device. The input signal waveform and coil current waveform are shown. FIG. 6 is a diagram showing another example of the magnetic field generating means used in the separation device. 1-photosensitive drum, 2-transfer paper, 9-separation device, 90-separation claw, 91-magnetic field generating means, applicant Hisao Komori, agent of Sharp Corporation, patent attorney, Fig. 1 (2R Near J 1, 3, and j Figure 4R Middle 5r''1 Figure 16

Claims (1)

[Claims] (11 times In a paper sheet separation device that separates paper sheets that are attached to the surface of a rotating drum using separating claws arranged opposite to the rotating direction of the rotating drum, the separating claws are separated from the surface of the rotating drum.) The magnetic field generating means is configured such that it can be brought into contact with and separated from the paper sheet, and a part of the magnetic body is made of a magnetic material, and the magnetic material is part of a magnetic path. 1. A paper sheet separating device, comprising means for generating an alternating magnetic field that turns on and off, and separating the paper sheets from a rotating drum surface while vibrating the separating claw with the alternating magnetic field.