JPH063939A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of toner sticking, etc., in a developing device and simultaneously, to simplify configuration by carrying a developer or toner on a developing roller, without rotating it. CONSTITUTION:The developing roller 161 is provided with an electrostatic actuator member composed of a stator 165 composed of an insulator and plural driving electrodes 164 buried in the stator 165 on a base roller 161a which can not be rotated. The electrostatic actuator member is divided in to two of a first electrostatic actuator carrying member 166a comprising a toner path for discharging the toner toward the surface of a latent image carrier form the inside of the developing device, and second electrostatic actuator carrying member 166b comprising a toner path for recovering the toner discharged from the inside of the developing device, thereinto. Then, a prescribed voltage is applied to the driving electrodes of these respective electrostatic actuator carrying members 166a and 166b to generate driving force by the mutual action of the charges of the toner and the stator and to carry the toner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a facsimile and a printer, and more specifically, it conveys a developer and a toner to the surface of a latent image carrier, and conveys a developer of a developing apparatus. It relates to improvement of means.

[0002]

2. Description of the Related Art In a conventional developing device, a developing roller, which is a developer conveying means, is rotated so that the developer or toner carried on the surface of the developing roller is transferred to an electrostatic latent image on a photoconductor, which is a latent image carrier. I was carrying it. After the completion of development, the developer or toner that has not been transferred to the photoreceptor is collected again in the developing device by the developing roller, and the developer or toner is newly carried on the developing roller and conveyed to the photoreceptor.

[0003]

However, according to the above construction, when the developing roller rotates, the toner enters between the developing roller and the side plate of the developing device supporting the developing roller, and the toner is rubbed to cause toner sticking. , Was adversely affecting the image. Further, in the case where the developing roller is composed of a developing sleeve having a built-in magnet roller, an eddy current is generated when the developing sleeve crosses the magnetic field of the magnet roller,
As a result, the torque of the developing roller may be increased, and the developing roller may be heated to melt the toner in the developing device. Further, in an image forming apparatus in which a plurality of developing devices using toners of different colors are arranged on a latent image carrier and one of the developing devices is selectively operated to form a multicolor image, It is necessary to switch the operation of the developing device in order to prevent color mixture of a plurality of toners on the body. Conventionally, a method of moving the developing device from the latent image carrier has been used for the switching operation of the operation developing device, and there is a problem that a moving mechanism is required. Further, in the image forming apparatus in which the developing device is configured to be detachable from the main body, when toner is present on the developing roller portion exposed inside and outside the device when the developing device is taken out from the main body, the toner is There was a problem of scattering.
Therefore, the present invention uses an electrostatic actuator carrying member as the developer carrying means of the developing device to carry the developer or toner without rotating the member carrying the developer, and at the same time, the electrostatic actuator carrying member. It is an object of the present invention to provide a developing device capable of solving the above-mentioned problems by the drive control of the developing device.

[0004]

In order to achieve the above object, the present invention provides an image provided with a developing device for supplying toner onto a latent image carrier to develop the latent image on the latent image carrier. In the forming apparatus, a developer conveying means of the developing device forms a toner path for discharging toner from inside the developing device toward the surface of the latent image carrier, and inside the developing device. And a second electrostatic actuator carrying member forming a toner path for collecting the toner discharged from the inside of the developing device.

[0005]

According to the present invention, the first electrostatic actuator conveying member forming a toner path for discharging the toner from the inside of the developing device toward the surface of the latent image carrier as the toner conveying means of the developing device and the inside of the developing device are discharged. A second electrostatic actuator carrying member that constitutes a toner path for collecting the toner in the developing device is used, and an electric charge is applied to a plurality of electrodes of each of the two electrostatic actuators to charge the toner. The interaction between the electric charge of the toner and the electric charges of the plurality of electrodes of the electrostatic actuator electrostatically generate a driving force, and thereby the toner is conveyed. And
When it is necessary to collect the toner existing in the portion exposed to the outside of the electrostatic actuator carrying means into the developing device, only the second electrostatic actuator carrying member is driven to carry out the second electrostatic actuator carrying. The toner existing on the member is collected in the developing device.

[0006]

FIG. 1 shows a schematic structure of an image forming apparatus according to an embodiment of the present invention. This image forming apparatus has 2
Two developing devices are provided opposite to the surface of the photoconductor drum to enable color image formation. First, an outline of the entire apparatus will be described. The photoconductor drum 1 (for example, an organic photoconductor; OPC) which is a latent image carrier is rotationally driven in the clockwise direction. When a document is placed on the contact glass 2 and a print switch (not shown) is pressed, the scanning optical system 5 including the document illumination light source 3 and the mirror 4 and the scanning optical system 8 including the mirrors 6 and 7 are moved, and the document is scanned. Scanning is performed. Then, the scanned image is read as an image signal by the image reading element 10 provided behind the lens 9. The read image signal is digitized, decomposed and converted for each color corresponding to the output device, and further image processed. A laser diode (LD) (not shown) is driven on the basis of each image-processed signal, the laser light from the LD is reflected by the polygon mirror 13, and then is irradiated onto the photosensitive drum 1 via the mirror 14. As a result, optical writing by laser light is performed on the photosensitive drum 1,
An electrostatic latent image is formed on the surface of the photosensitive drum that has already been uniformly charged by the charging charger 15. This electrostatic latent image is visualized by two developing devices, a first developing device 16a and a second developing device 16b, and this visible image is transferred to a transfer paper sent from a paper feeding section 17 by a transfer charger 18 Transferred by corona discharge. After this transfer, the transfer paper is separated from the surface of the photosensitive drum by the separation charger 19. The separated transfer paper is conveyed by the conveyor belt 21, passes through the contact portion of the fixing roller pair 22, the transfer image on the transfer paper is fixed, and then the transfer paper is ejected to the outside of the apparatus. On the other hand, the toner remaining on the surface of the photoconductor after the transfer is removed by the cleaning device 23. Here, in the two-color image formation, the process of forming the corresponding latent image on the photoconductor drum and the visualization process by the corresponding developing device are performed by one rotation of the photoconductor drum for each color. It is also possible to perform the rotation one copy cycle, for example, the first developing device 16a and the second developing device 16a.
An optical writing section for forming a latent image of the second color is provided between the developing devices 16b (not shown), the latent image of the first color is formed and developed, and then the latent image of the second color is continuously formed. The two-color image may be formed by performing one rotation of the photosensitive drum after forming and developing, or the two-color image may be formed by another well-known two-color image forming method.

Next, the developing device will be described. In FIG. 2, the first developing device 1 faces the surface of the photosensitive drum.
Two developing devices 6a and a second developing device 16b are provided. The first developing device 16a uses a one-component non-magnetic toner of red color, for example, and the second developing device 16b uses a one-component non-magnetic toner of black, for example. Both developing devices have the same configuration except that the colors of the toners used are different. Second developing device 16
An explanation will be given based on b. The developing device 16b includes a developing roller 161, which is a toner transporting means, and a charging roller 162 that abuts and rotates on the surface of the developing roller 161 to frictionally charge the toner.
And an agitator 163 for conveying the toner in the toner hopper to the vicinity of the charging roller 162. The developing roller 161 is a base roller 1 that is non-rotatably supported.
An electrostatic actuator member composed of a stator 165 made of an insulator and a plurality of electrodes (hereinafter, referred to as drive electrodes) 164 embedded in the stator 165 is provided on the 61a. The electrostatic actuator member includes a first electrostatic actuator transport member 166a that constitutes a toner path for discharging toner from the developing device toward the surface of the latent image carrier.
It is divided into two parts, a second electrostatic actuator carrying member 166b which constitutes a toner path for collecting the toner discharged from the developing device into the developing device. Specifically, the portion facing the photosensitive drum 1 is configured by a first electrostatic actuator transport member 166a, and the charging roller 162 is divided so as to face the second electrostatic actuator transport member 166b. Each electrostatic actuator transport member 1
66a and 166b, the plurality of drive electrodes 164 are
Each of the base rollers 161 has an elongated strip shape in the axial direction. The pitch of the drive electrodes 164 in the circumferential direction of the developing roller 161 may be set to, for example, about 10 to 20 μm so that the toner particles having a diameter of about 10 μm adhere to one drive electrode 164 in a line. (Fig. 3
Alternatively, the width and pitch in the same circumferential direction may be set to be larger than this, and the toner particles may be attached in a plurality of rows on one drive electrode. Then, in the first electrostatic actuator transport member 166a, as shown in FIG. 3A, for example, adjacent electrodes are different from each other in the first to third areas.
Connected to any of the electrode terminals 164a, 164b, 164c to form three drive electrode groups. Similarly, in the second electrostatic actuator transport member 166b, adjacent electrodes are different from each other in the fourth to fourth electrode groups. It is connected to any of the sixth electrode terminals to form three drive electrode groups.
The first to third electrode terminals 164a, 164b, 164c for the first electrostatic actuator carrying member 166a
And the fourth to sixth electrode terminals of the second electrostatic actuator carrying member 166b are both carrying members 166 and 166.
b are connected to respective drive circuits so that they can be independently driven and controlled. Then, these electrostatic actuator transport members 166a and 166b apply toner to the first to third electrode terminals 164a, 164b and 164c and the fourth to sixth electrode terminals by applying a voltage as described below. The interaction between the electric charge and the electric charge of the stator generates a driving force to convey the toner.

In the toner hopper of each of the developing devices 16a and 16b, there is contained toner which is triboelectrically charged to the positive polarity (+) by the charging roller 162, for example. As this toner, for example, a conventionally known one-component toner in which a charge control agent is added to a toner resin so as to be triboelectrically charged to a predetermined polarity and which has a resistance enough to hold a triboelectric charge is used. Can be done. Then, the toner end detection is performed by detecting the rotation torque of the agitator 163, and assuming that the toner has run out in the developing device 16 because the rotation torque has fallen below a predetermined value, and the toner end has been detected. Indicates the toner end to the user by lighting a toner end display (not shown) on the operation unit, for example.

With reference to FIG. 3, the operation principle of, for example, conveying toner in the right direction in the drawing by the electrostatic actuator conveying member will be described. In the illustrated example, as can be seen from the reference numerals of the electrode terminals, the first electrostatic actuator conveying member 1
The second electrostatic actuator carrying member 166b has the same operating principle as that of 66a. Figure 3
As in (a), any of the electrode terminals 164a, 164
There is no charge in the drive electrode 164 when no voltage is applied to b and 164c. On the other hand, the toner is triboelectrically charged by the charging roller 162 and is positively charged, but since there is no electric charge on the stator side, the toner is not controlled by the drive electrode 164 and the toner is not conveyed. . At this time, the toner floats around the developing roller 161 or adheres to the stator by some force. From this state, as shown in FIG. 3B, a positive voltage is applied to the first electrode terminal 164a, a negative voltage is applied to the second electrode terminal 164b, and 0V is applied to the third electrode terminal 164c. Then,
The toner is attracted to the drive electrode to which a voltage having a polarity opposite to the charging polarity is applied. That is, + toner adheres to the surface of the developing roller on the drive electrode 164 to which −V is applied. At this time, the toner is not attracted to the drive electrode 164 to which the + V voltage having the same polarity as the toner is applied and the drive electrode 164 to which the applied voltage is not applied. Next, as shown in FIG. 3C, + V having the same polarity as the toner is applied to the second drive electrode group below the adhered toner as shown in FIG. 3C. (In this example, on the right side), the adjacent third electrode group is provided with −V, which has the opposite polarity to the toner, and the first drive electrode group, which is adjacent to the second drive electrode in the toner transport direction, has the same polarity as the toner. Then, it is switched so as to apply + V. As a result, the charge of the toner has the same polarity as the charge of the drive electrode immediately below it, so that a repulsive force is generated and a levitation force is generated for the toner, and the third drive electrode group in the toner transport direction is 0. Changes from −V to −V and has the same polarity as the toner, the electric charge of the third driving electrode group attracts the upper left toner, and the electric charge of the first driving electrode group opposite to the toner conveying direction is Since it has the same polarity as the toner, it repels the toner on the upper right of the toner, and a driving force in the right direction is generated in the toner. The levitation force reduces the friction between the toner and the surface of the developing roller, and the driving force of the electric charges causes the toner to move about one pitch of the driving electrode. Next, in order to shift the voltage (FIGS. 3 (c) and 3 (d)) of the pattern for performing repulsion and driving of the toner by one, as shown in FIGS. 3 (e) and 3 (f), Switch the applied voltage. Thereafter, in the same manner, by applying the driving electrodes while shifting them one by one, the toner is continuously moved. Here, the switching of the applied voltage to each drive electrode group from FIG. 3 (b) to FIG. 3 (f) and after that is summarized as shown in Table 1. The steps in the table are shown in FIG. 3B, and the steps are shown in FIGS. 3C and 3D.
Steps correspond to FIGS. 3E and 3F. The steps include + V, − for each of the first to third drive electrode groups.
V and + V are applied, and the voltage of the pattern for repulsing and driving the toner is shifted from the step by one to the right side in the toner conveying direction. After that, by repeating steps 1 to 3, the pattern voltages for repulsing and driving the toner are shifted one by one.

[Table 1] Note that, for example, in FIG. 3C (step), if the voltage applied to the third drive electrode group is made positive and the first drive electrode group is made negative, it is possible to drive in the opposite direction.

Based on the above operation principle, in the configuration of this embodiment, both developing devices 16a and 16b are brought into an operating state (a state in which the developing operation is being performed) based on a well-known two-color image forming process. During the operation of each of the developing devices 16a and 16b, the toner in the toner hopper is conveyed to the charging roller 162 by the agitator 163, charged to a predetermined polarity by the charging roller 162, and then conveyed to the surface of the developing roller 161. . The toner carried to the developing roller 161 is carried to the surface of the photoconductor by the first electrostatic actuator carrying member 166a and the second electrostatic actuator carrying member 166b which are in the driven state, and is provided for development. The residual toner on the surface of the developing roller 161 is collected in the developing device. Then, each developing device 16a,
For both 16b, after the development operation is completed, in order to prevent color mixture of toner on the photoconductor drum, no toner is present on the second electrostatic actuator transport member 166b facing the photoconductor drum surface. Therefore, only the second electrostatic actuator carrying member 166b is driven to collect the toner on the member in the developing device. During this time, the first electrostatic actuator carrying member 166a is not driven because the toner in the developing device is carried onto the second electrostatic actuator carrying member 166b by the driving of the first electrostatic actuator carrying member 166a. This is because it is not possible to make the toner-free state on the second electrostatic actuator transport member 166b facing the drum surface.

As described above, according to the present embodiment, the toner is conveyed by using the electrostatic actuator member without rotating the developing roller 161, so that there is no portion rubbed by the rotation of the developing roller 161, and such a portion is removed. The toner that has entered will not be stressed and will not stick to the toner. Further, since the developing roller 161 does not rotate, the increase of torque and the generation of heat due to the generation of eddy current are suppressed, and the toner in the developing device is not melted. According to the present embodiment, in the conventional image forming apparatus of this type, in order to prevent the color mixture of the toner on the photosensitive drum, the developing device after the developing operation is retracted from the surface of the photosensitive member. Compared with the above, it is advantageous in that the device can be simplified and downsized. In the above embodiment, two developing devices are arranged facing the surface of the photoconductor, but the present invention is not limited to this and can be applied to a case where three or more developing devices are arranged facing each other. Further, the present invention can be applied to an image forming apparatus having a plurality of developing devices so that the operator can select the color of a single color image. Further, in an image forming apparatus provided with only one developing device, wherein the developing device is configured to be attachable to and detachable from the main body of the developing device, when the developing device is taken out from the main body, it is exposed inside and outside the device. The configuration of the developing device of this embodiment can be used to prevent toner from existing on the developing roller portion.

[0012]

As described above, according to the present invention, the electrostatic actuator transporting means is used as the developer transporting means of the developing device, whereby the toner is supplied onto the latent image carrier, so that the developer transporting means is carried out. It is not necessary to rotate the means, and it is possible to solve problems such as toner adhesion in the developing device and an increase in drive torque. Further, since toner is conveyed without using a rotating member such as a conventional developing roller, toner scattering due to centrifugal force and scattered toner such as when using a rotating member may contaminate the transfer device or the like. Therefore, an abnormal image is not generated, and further, a defect such as a defective application of a developing bias voltage due to a voltage being applied from a developing bias power source through a bearing of a member that rotates is not caused. Further, the electrostatic actuator carrying means discharges the toner from the inside of the developing device toward the surface of the latent image carrier, and a first electrostatic actuator carrying member forming a toner path, and the inside of the developing device. A second electrostatic actuator carrying member that constitutes a toner path for collecting toner into the developing device, and during the developing operation, both the first electrostatic actuator carrying member and the second electrostatic actuator carrying member are provided. By driving, the toner is supplied from the inside of the developing device onto the latent image carrier and the residual toner after the development is collected into the developing device, while the toner is exposed to the outside of the electrostatic actuator carrying means. When it is necessary to collect the existing toner in the developing device, only the second electrostatic actuator carrying member is driven to exist on the second electrostatic actuator carrying member. It can be recovered toner in the developing device. Therefore, an operating developing device in an image forming apparatus in which a plurality of developing devices using toners of different colors are arranged on the surface of the latent image carrier and one of the developing devices is selectively operated to form a multicolor image. When only the second electrostatic actuator carrying member is driven during the switching operation of, the color mixture of the toner on the latent image carrier can be prevented without using the moving mechanism of the developer carrying means with respect to the latent image carrier. Therefore, it is possible to simplify the mechanism and improve the positional accuracy of the developer transport means with respect to the latent image carrier. Further, in the image forming apparatus in which a single developing device is arranged opposite to the surface of the latent image carrier, when the developing device is taken out from the apparatus body, only the second electrostatic actuator carrying member may be driven before the taking-out operation. For example, it is possible to prevent the toner from scattering when the developing device is taken out with a simple structure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

2 is a schematic configuration diagram of a developing device of the image forming apparatus of FIG.

FIG. 3A to FIG. 3F are explanatory views of a toner conveying operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 16a 1st developing device 16b 2nd developing device 161 Developing roller 162 Charging roller 163 Agitator 164 Drive electrode 165 Stator 166a 1st electrostatic actuator conveyance member 166b 2nd electrostatic actuator conveyance member

Claims (1)

[Claims] 1. An image forming apparatus comprising a developing device for supplying a toner onto a latent image carrier to develop a latent image on the latent image carrier, wherein a developer conveying means of the developing device is the developing device. A first electrostatic actuator carrying member that forms a toner path for discharging toner from inside toward the surface of the latent image carrier, and a toner path that collects the toner discharged from inside the developing device into the inside of the developing device And a second electrostatic actuator transport member that controls the image forming apparatus.