JPS63131158A - Electrostatic discharging performing device - Google Patents

Abstract

PURPOSE:To reduce the overall size of a device and to reduce the manufacture cost by interposing at least one rectifying element between at least two electrostatic discharging means and a voltage source and applying a high voltage with a specific polarity to an electrostatic discharging means. CONSTITUTION:An electrostatic copying machine equipped with a rotary drum 4, a corona discharging means 10 for transfer, a corona discharging means 12 for separation, etc., is so constituted that 1 st diode 44 is connected forward between the corona discharging means 10 for transfer and the voltage source 42 and a 2nd diode 46 is connected reversely between the corona discharging means 12 for separation and the voltage source 42. Consequently, a positive high voltage is applied to the corona discharging means 10 for transfer to perform transfer to copying paper and a negative high voltage is applied to the corona discharging means 10 for separation to separate the copying paper. Consequently, only one voltage source is required to apply the two discharging means 10 and 12 with the high voltages, and the device is therefore reduced in size and cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a discharge generating device, and more particularly to a discharge generating device suitable for applying discharge toward a photoreceptor in an electrostatic copying machine, for example.

<Prior Art> For example, in an image generating machine such as a static copying machine, as is well known to those skilled in the art, a charging corona discharge means for applying an electric charge to a photoconductor is used, and a toner image formed on the photoconductor is transferred to a copy paper. The apparatus is equipped with a discharge generating device including various corona discharge means, such as a transfer corona discharge means for transferring the image to the surface of the photoreceptor, and a peeling corona discharge means for peeling off the copy paper that is in close contact with the surface of the photoreceptor. A dedicated voltage source is provided corresponding to each corona discharge means. That is, when selenium is used as the photoreceptor, the charging corona discharge means is connected to a charging voltage source that applies a positive high voltage, and the transfer corona discharge means is connected to a transfer voltage source that applies a positive high voltage. The stripping corona discharge means is connected to a stripping voltage source that applies a negative high voltage or an alternating current high voltage.

However, in the above-mentioned discharge generating device applied to, for example, an image generator, there is a dedicated voltage source corresponding to each corona discharge means, which has the disadvantage that the entire device becomes large and the manufacturing cost increases.

<Object of the Invention> The present invention has been made in view of the above-mentioned facts, and its main purpose is to solve the above-mentioned conventional drawbacks and to create a novel product which is particularly suitable for image generation machines such as electrostatic copying machines. Another object of the present invention is to provide an excellent discharge generating device.

<Summary of the Invention> According to the present invention, at least two discharge means, a voltage source for applying a high voltage to the at least two discharge means, and a combination of the at least two discharge means and the voltage source are provided. and at least one rectifier interposed between the discharge means, the voltage source generates an AC high voltage, one discharge means is given a high voltage of a specific polarity by the action of the rectifier, and the other One discharge means is provided with a discharge generating device to which a high voltage or an AC high voltage of a polarity opposite to the specific polarity is applied.

<Preferred Specific Example of the Invention> Hereinafter, a specific example of a discharge generating device configured according to the present invention will be described with reference to the accompanying drawings. In the illustrated specific example, the discharge generating device will be described in terms of an electrostatic copying machine as an example of an image generating machine.

In FIG. 1, which schematically illustrates an electrostatic copying machine as an example of an image forming apparatus, a photoconductive layer such as selenium or zinc oxide is coated on the circumferential surface of a rotating drum 4 that is rotationally driven in the direction indicated by an arrow 2. A photoreceptor is provided.

Around the rotating drum 4, in order in the rotational direction shown by the arrow 2, there are provided a charging corona discharge means 6, a developing device 8, a transfer corona discharge means 1O1, a peeling corona discharge means 12, a cleaning device 14, and a static elimination means 16. is installed. The charging corona discharging means 6 disposed in the charging area 18 applies corona discharge to the rotating drum 4, and in this way, a charge of a specific polarity is first applied substantially uniformly to the surface of the photoreceptor (charging step). Next, an image of an original (not shown) to be copied is placed on the rotating drum 4 in an exposure area 20 located downstream of the charging area 18 in the direction of rotation shown by the arrow 2, as shown by a dashed line.
is irradiated onto the photoconductor (exposure step), thus forming an electrostatic latent image corresponding to the original image on the surface of the photoconductor (electrostatic latent image forming step). Exposure area 20 when viewed in the rotational direction shown by arrow 2
The developing device 8 disposed downstream of the cylindrical sleeve 24 and the cylindrical sleeve 2 rotated in the direction shown by the arrow 22.
The magnetic brush mechanism 28 includes a permanent magnet 26 disposed within the magnetic brush mechanism 4. The magnetic brush mechanism 28 holds the developer on the surface of the cylindrical sleeve 24 and transports it in the direction shown by the arrow 22, and applies the developer to the surface of the photoreceptor after the electrostatic latent image forming process in the development area 30. The electrostatic latent image on the photoreceptor is developed into a toner image. In the transfer area 32 located downstream of the development area 30, transfer paper such as plain paper supplied from a copy paper supply means (not shown) constituted by a paper feed cartridge is placed in close contact with the other as shown by the two-dot chain line. I am forced to do it. Further, the transfer corona discharge means 10 includes a transfer area 32.
At this step, a corona discharge is applied to the back side of the transfer paper that is brought into close contact with the surface of the photoreceptor, and the toner image on the surface of the photoreceptor is thus transferred to the copy paper (transfer step). Transfer corona discharge means 1
The stripping corona discharge means 12 disposed downstream of the
Corona discharge is applied to the back side of the copy paper after the transfer process, and the copy paper that has been brought into close contact with the surface of the rotating drum 4 is peeled off from the surface as shown by the two-dot chain line.

The thus peeled copy paper is then conveyed to a device comprising, for example, a pair of heat fixing rollers, and the toner image is fixed on the surface of the copy paper by the action of the fixing device. (Fixing process). On the other hand, the photoreceptor to which the toner has been transferred is further moved in the direction shown by arrow 2 through the cleaning area 34 and the static elimination area 36. The cleaning device 14 disposed in the cleaning area 34 includes a cleaning blade 38 that acts on the photoreceptor surface.

The cleaning blade 38 acts on the surface of the photoreceptor to remove residual toner remaining on the photoreceptor after transfer (cleaning step). The static eliminating means 16 disposed in the static eliminating area 36 includes a static eliminating lamp 40 in a specific example. The charge eliminating lamp 40 irradiates the surface of the photoreceptor after the cleaning process, thereby removing residual charges remaining on the surface of the photoreceptor. (static elimination process).

In the above electrostatic copying machine, when selenium is used as the photoreceptor disposed on the circumferential surface of the rotating drum 4, the charging corona discharge means 6 performs positive corona discharge, and the transfer corona discharge means 10 applies a positive corona discharge, and the stripping corona discharge means 12 applies a negative or alternating current corona discharge. On the other hand, when zinc oxide is used as the photoreceptor, the charging corona discharge means 6 applies negative corona discharge, the transfer corona discharge means 10 applies negative corona discharge, and the peeling corona discharge means 6 applies negative corona discharge. The discharge means 12 performs positive or alternating current corona discharge.

In the illustrated example, the transfer corona discharge means 10 and the peeling corona discharge means 12 constitute a part of the discharge generating device according to the present invention. Next, Fig. 2 and Fig. 3-A
Further explanation will be given with reference to FIGS. 3-3C. In the following, a case will be described in which selenium, for example, is used as the photoreceptor.

Mainly referring to FIG. 2, the transfer corona discharge means 10 and the peeling corona discharge means 2, which constitute a part of the discharge generating device according to the present invention, are equipped with a voltage source 42 that generates a high voltage.
It is connected to the. It is important that the voltage source 42 generates an AC high voltage. Then, the transfer corona discharge means 10, the peeling corona discharge means 12, and the voltage source 42.
It is important that at least one rectifying element such as a high voltage diode is interposed between the two. In a specific example, as shown in FIG.
A first diode 44 is connected in the forward direction between the stripping corona discharge means 12 and the voltage source 42.
A second diode 46 is connected in the opposite direction between the two.

In an electrostatic copying machine equipped with such a discharge generating device, it is preferable that the voltage source 42 generates a square wave AC high voltage as shown in FIG. 3-A. A high voltage from a voltage source 42 is provided to a first diode 44 and a second diode 46 . Since the first diode 44 is connected in the forward direction, only a positive voltage is supplied through the first diode 44, and the transfer corona discharge means 10
A positive high voltage having a waveform shown in FIG. 3-B is applied to. On the other hand, since the second diode 46 is connected in the opposite direction, only a negative voltage is supplied through the second diode 46, contrary to the first diode 44.
A negative high voltage having a waveform shown in FIG. 3-C is applied to the stripping corona discharge means 12. Therefore, in the specific example, a positive high voltage is applied to the transfer corona discharge means 10 and the stripping corona discharge means 12 by a combination of a voltage source 42 that generates an AC high voltage and two high voltage diodes 44 and 46. Thus, the transfer corona discharge means 10 applies a positive corona discharge to the back side of the copy paper, and the peeling corona discharge means 12 applies a negative corona discharge to the back side of the copy paper. give As is easily understood, when zinc oxide is used as the photoreceptor, the first diode 44 may be connected in the opposite direction, and the second diode 46 may be connected in the forward direction.

In the illustrated example, a second diode 46 is interposed between the stripping corona discharge means 12 and the voltage source 42, but an AC high voltage is applied to the stripping corona discharge means 12 (therefore, the stripping corona discharge means 12 is If the corona discharge means 12 performs an alternating current corona discharge, the second diode 46 can also be omitted.

In the specific example, the high voltage from the voltage source 42 is supplied to the transfer corona discharge means 10 and the stripping corona discharge means 12, but is also supplied to the charging corona discharge means 6. You can also. In such a case, the charging corona discharge means 6 and the voltage? A high voltage diode (not shown) may be placed and connected in the forward direction (in the reverse direction if zinc oxide is used as the photoreceptor) between the photoreceptor and the photoreceptor. Thus, the charging corona discharge means 6
Similarly to the transfer corona discharge means 10, a positive high voltage shown in FIG. 3-B is applied to the charging corona discharge means 6, and the charging corona discharge means 6 applies a positive corona discharge to the surface of the photoreceptor of the rotating drum 4. In such a case, as understood from FIG. 1, the charging corona discharge means 6 is energized somewhat earlier than the transfer corona discharge means 10 and the peeling corona discharge means 12, and is deenergized somewhat earlier. For example, a switching means (not shown) may be used so that the specific portion of the rotating drum 4 is energized and deenergized earlier in the time required to move from the charging area 18 to the transfer area 32 in the direction shown by the arrow 2. ) is desirable.

Further, as the static eliminating means 16, a static eliminating corona discharge means (not shown) can be used instead of the static eliminating lamp 40, and in such a case, the high voltage from the voltage source 42 is supplied to the static eliminating corona discharge means. It can also be configured to In such a configuration, the corona discharge means for static elimination may be connected to the voltage source 42 to apply an alternating current high voltage.

In the specific example described above, as shown in FIGS. 1 and 2, the transfer corona discharge means 10 and the peeling corona discharge means 12 (and the charging corona discharge means 6) have wire electrodes stretched inside the shield. Although it is composed of a so-called corotron, it is not limited to this, but it can also be composed of a so-called scotron, in which a wire electrode is disposed within the shield and a grid is disposed in the opening of the shield. . In addition, instead of the corotron and scotron, a discharge means shown in FIG. 4 or 5 (the discharge means shown in FIGS. 4 and 5 can be used mainly for ff1ll release corona discharge) is used. be able to.

The discharge means shown in FIG. 4 consists of an elongated plate member 48 made of an electrically conductive material, the negative end of which is formed into a serrated shape. In such a plate member 48, the serrated portion acts as an electrode, and the same effect as that of a corotron or the like is achieved. Further, the discharge means shown in FIG. 5 is composed of an elongated support body 5° made of a conductive material and a conductive brush 52 embedded in one side of the support body 50 along the longitudinal direction. In such a discharge means, the conductive brush 52 acts as an electrode, and the same effect as a corotron or the like is achieved.

Although a specific example of the discharge generating device configured according to the present invention has been described above by applying it to an electrostatic copying machine as an example of an image generator, the present invention is not limited to this specific example. Various modifications and variations can be made without departing from the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram showing a part of an electrostatic copying machine equipped with a specific example of a discharge generating device constructed according to the present invention. FIG. 2 is a simplified diagram showing a transfer corona discharge means, a peeling corona discharge means, and related elements in the electrostatic copying machine of FIG. 1. Figures 3-A to 3-C show the AC high voltage generated by the voltage source in Figure 2, the positive high voltage applied to the corona discharge means for transfer, and the corona discharge means for stripping, respectively. The figure which shows each waveform of the negative high-voltage voltage applied to. FIG. 4 is an enlarged perspective view showing a modification of the discharge means. FIG. 5 is an enlarged perspective view of another modification of the discharge means. 4...Rotating drum 6...Corona discharge means for charging 8...Developing device 10...Corona discharge means for transfer 12...
- Stripping corona discharge means 42... Voltage source

Claims (1)

[Claims] 1. At least two discharge means, a voltage source for applying high voltage to the at least two discharge means, and between the at least two discharge means and the voltage source. and at least one rectifying element interposed therebetween, the voltage source generates an AC high voltage, one discharge means is given a high voltage of a specific polarity by the action of the rectifying element, and the other one A discharge generating device in which a high voltage or an AC high voltage having a polarity opposite to the specific polarity is applied to the discharge means. 2. The at least two discharge means include a transfer corona discharge means for transferring the toner image formed on the photoreceptor to a copy paper in an electrostatic copying machine, and a peeling corona discharge means for peeling off the copy paper that is in close contact with the photoreceptor. The discharge generating device according to claim 1, comprising corona discharge means. 3. The rectifying element is interposed between the transfer corona discharge means and the voltage source, and the high voltage of the specific polarity is applied to the transfer corona discharge means by the action of the rectifier,
3. The discharge generating device according to claim 2, wherein the stripping corona discharge means is supplied with an AC high voltage from the voltage source. 4. The rectifying element is interposed between the transferring corona discharge means and the peeling corona discharge means and the voltage source, one of the rectifying elements being connected in the forward direction and the other of the rectifying elements being connected in the forward direction. are connected in opposite directions, and a high voltage of the specific polarity is applied to the transfer corona discharge means, while a high voltage of the opposite polarity to the specific polarity is applied to the peeling corona discharge means. 2. The discharge generating device according to item 2. 5. The at least two discharging means further include charging corona discharging means for applying an electric charge to the photoreceptor in the electrostatic copying machine, and a charging corona discharging means is also provided between the charging corona discharging means and the voltage source. The discharge generating device according to any one of claims 2 to 4, wherein a rectifying element is interposed, and a high voltage of the specific polarity is applied to the charging corona discharge means.