JP2001117362A - Developing device for one-component toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner from being fixed to a developing roller when a developing action is executed with the one-component toner by using the developing roller. SOLUTION: This developing device is provided with a supply roller 42 driven to be rotated by being made to press-contact with the developing roller 41 carrying the one-component toner and feeding it to a photoreceptor carrying an electrostatic latent image in order to supply the toner to the roller 41 and a regulation roller 43 for regulating the quantity of toner supplied to the roller 41 so as to make it constant. When the developing action is finished, the rotation of the roller 41 is stopped. In accordance with this stop control, the roller 43 or the roller 42 or both of the rollers 43 and 42 are rotated in a prescribed time in a direction being reverse to the time of the developing action. Thus, the toner intervening between the rollers 43 and 42 and the roller 41 is eliminated and prevented from being fixed after the roller 41 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for visualizing an electrostatic latent image formed on an electrostatic latent image carrier with a toner as a colorant, and more particularly, to a one-component toner. The present invention relates to a developing device using a developer having a configuration.

[0002]

2. Description of the Related Art According to an image forming apparatus employing an electrophotographic method, such as a copying machine or a printer, an electrostatic latent image is formed on a surface of a photosensitive member which is an image bearing member for carrying a latent image or the like. A developing device is provided which supplies a developer such as a toner, which is a colorant, to the photoreceptor side in order to visualize the toner and selectively adheres the toner.

[0003] The developing device develops the electrostatic latent image formed on the photoreceptor, and the developed toner image is transferred to a transfer material sheet or the like. Then, after the transfer, a part of the toner that has not been transferred remains on the surface of the photoconductor. The remaining unnecessary toner is also removed from the photoreceptor surface in order to repeatedly perform the next image formation. Therefore, a cleaning device that removes the toner remaining on the surface of the photoconductor after the transfer is provided, and the unnecessary toner removed by the cleaning device is stored in a storage unit in the cleaning device.

Therefore, in the image forming apparatus having the developing device as described above, the space for arranging the process means for forming an image around the photoreceptor is reduced in accordance with the miniaturization. There has been a strong demand for miniaturization.

Therefore, as a developing device, a developing device using a one-component toner without using a two-component developer composed of a toner and a magnetic carrier has been proposed and put into practical use. . In a developing device using such a one-component toner, it is not necessary to control the toner concentration, and since the carrier is not present, the volume of the developing tank can be greatly reduced, and thus the developing device can be downsized. . At the same time, simplicity such as maintenance is excellent. That is, since there is no need to replace the deteriorated developer, particularly the developer due to deterioration of the carrier, maintenance for the replacement is not required.

Further, it is only necessary to replenish the toner, there is no need to detect the toner density, and no control is required for that, so that the control is simplified. In particular, in a developing device using a one-component toner, it is only necessary to replenish the toner when necessary.

For example, as shown in FIG. 4, a developing device 4 for visualizing an electrostatic latent image formed on the photoconductor 1 is opposed to the photoconductor 1 as an image carrier. Are located. The developing device 4 includes a toner 1 as a one-component developer.
The developing roller 41 is rotatably provided so as to oppose particularly the opening of the developing tank 40 that accommodates the developing roller 41. The developing roller 41 is partially exposed at the opening of the developing tank 40,
For example, it is arranged so as to contact the photoconductor 1. The contact area is a development area.

The developing roller 41 carries a one-component toner on its surface and transports the toner to a developing area facing the photoreceptor 1. After the development, the toner not contributing to the development is transported into the developing tank 40 and collected. In order to temporarily remove the collected toner from the surface of the developing roller 41, a supply roller 42 is provided so as to be in pressure contact with the developing roller 41, and the toner carried on the surface of the developing roller 41 is scraped off. The toner is newly supplied to the surface of the developing roller 41 by the supply roller.

The one-component toner is supplied by the supply roller 42 and is adsorbed on the surface of the developing roller 41, and a regulating member 43 pressed against the surface of the developing roller 41 is provided in order to regulate the amount of adsorption. . The amount of the toner that has passed through the regulating member 43 is regulated to a fixed amount, reaches the developing area in contact with the photoconductor 1 as described above, and forms an electrostatic latent image formed on the surface of the photoconductor 1. Selectively adhere according to
Development will be performed. A developing device having such a configuration is proposed in, for example, Japanese Patent Application Laid-Open No. 3-33776.

Therefore, as the regulating member 43, there is a regulating member 43 which is not provided with a roller structure as shown in FIG. In such a configuration, the life of the plate-shaped regulating member 43 is determined by the degree of progress of wear of the contact portion that contacts the developing roller 41. This contact portion is located on the developing roller 4
When the roller 1 rotates, it comes into sliding contact with the developing roller 41 and is worn by this contact. When the wear progresses and the contact portion becomes unusable, the life of the regulating member 43 is reached. In the leaf spring-shaped regulating member 43, only a specific portion of the contact portion which is fixed is always in contact with the peripheral surface of the developing roller 41 and is rubbed, and the contact portion remains unchanged and is significantly worn.

If a plate-shaped member is used as the regulating member 43, the structure can be simplified and the cost can be reduced. However, as described above, the abrasion is remarkable at the contact portion with the developing roller 41 as described above. Become. Moreover, the regulating member 43
Is likely to occur in the portion where the toner is in contact with the developing roller 41. If the toner adheres, the amount of adhesion of the developing roller 41 at that portion becomes different from that of the other portions, and it is extremely thin, and a large amount of the toner adheres, and the uniform toner layer thickness state is broken. This results in white and black streaks due to development.

Accordingly, there is a problem that the service life of the regulating member 43 is shortened due to the above-mentioned problems caused by the wear and the sticking of the toner.
For this reason, conventionally, as shown in FIG. 4, the regulating member 43 has a roller structure, so that the contact portion with the developing roller 41 is not fixed, so that it is possible to reduce the adhesion of the toner and extend the life.

If the regulating member 43 has a roller structure, the amount of toner adhered to the developing roller 41 is naturally stabilized, and the unevenness of the charge amount of the toner can be effectively prevented. Regulation member 43 having such a roller structure
However, there is a problem that toner sticks. For example, when the developing operation by the developing roller is completed, and finally the rotation including the developing roller is performed, the toner adhering to the developing roller is pressed by a regulating roller pressed against the developing roller, and the toner is transferred to the developing roller during development. The potential difference due to the bias voltage is set so as to cause a step in the drawing direction, and accordingly, the toner may be fixed to the developing roller.

In the developing device having the structure shown in FIG. 4, not only the above-mentioned phenomenon occurs at the position of the regulating member 43 but also the same phenomenon may occur at the position of the supply roller 42. In other words, the supply roller 42 is also rotated while being pressed against the developing roller 43, and acts to supply the toner to the developing roller 41 and to scrape off the toner after development. However, since the supply roller 42 is also stopped by stopping the developing roller 41 at the end of the development, the residual toner is nipped between the developing roller 41 at this position and the toner is fixed to the developing roller 41,
Further, the toner may adhere to the supply roller 42 side.

If the toner adheres to the developing roller 41 as described above, the developing conditions change, and not only good development cannot be performed, but also the toner cannot be uniformly applied to the developing roller 41, and stripes or white spots occur during development. This leads to a decrease in image quality.

Japanese Patent Application Laid-Open No. 2-168687 discloses that a regulating member having a roller structure is provided, and a cleaning blade or the like is provided for removing toner adhering to the regulating member each time. With such a configuration, an effect of suppressing adhesion of toner between the developing roller and the regulating roller can be expected.

[0017]

As described above, in the case where a cleaning member for scraping off the adhered toner is provided on the regulating roller 43 having the structure shown in FIG. The pressing condition of the members becomes a problem, and the adjustment and the like become very troublesome. In particular, if the pressing force is increased to enhance the cleaning effect, the surface of the regulating roller may be damaged, and if the pressing force is too small, the cleaning effect cannot be expected.

Accordingly, even if a cleaning member is provided to scrape off the toner remaining on the surface of the regulating roller, and the toner is pressed between the developing roller and the regulating roller at the end of the development, it is possible to suppress the adhesion of the toner to some extent. As described above, the adjustment work is very troublesome.

Furthermore, the surface of the regulating roller is cleaned, and after the cleaning, the surface is pressed against the developing roller.
Even if the toner is regulated to a fixed amount, the developing roller is supplied with toner for development via a supply roller,
If the amount is regulated only by the regulating roller and the roller is stopped by the end of the development, toner is inevitably interposed between the regulating roller and the developing roller, and the toner is left for a long time in a state of being pressed against the toner. However, problems such as sticking of toner and toner cannot be effectively solved.

In addition, the problem of toner sticking is not a phenomenon that occurs only between the regulating roller and the developing roller.
May occur between the developing roller 41 and the supply roller 42 as shown in FIG. The prevention of such toner sticking is as follows.
Even if the configuration in which the cleaning member is provided for the regulating roller as described in the above-mentioned conventional publication is employed, the fixation of the toner cannot be fundamentally eliminated as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a developing device using a one-component toner, which includes a simple means for preventing toner from sticking to a developing roller.

That is, an object of the present invention is to remove the toner interposed between the developing roller and the developing roller by controlling the rotation of the regulating roller or the supply roller after the development to solve the problem such as toner sticking. Provided is a developing device that eliminates a factor of toner sticking.

[0023]

According to a first aspect of the present invention, there is provided a developing device using a one-component toner according to the present invention. A supply roller for supplying toner to the developing roller before the developing roller conveys the toner to the developing area; and a step for supplying the toner supplied to the developing roller to the developing area. And a regulating roller that regulates the electrostatic latent image on the electrostatic latent image carrier in a developing area, and the regulating roller or the supply roller is rotated in a rotational direction at the time of development. It is characterized by including a control unit for performing rotational drive control in a reverse direction for a predetermined time.

According to such a configuration, the regulation roller and the supply roller are stopped in synchronization with the stop of the rotation of the development roller at the end of the development, and the toner adhering to the development roller remains. Alternatively, the toner is pinched between the supply rollers and pressed with a considerable pressure, so that the toner may adhere at that position. But,
When the regulating roller is rotated for a predetermined time in a direction opposite to that during the development after the development is completed, the toner adhered to the development roller is swept and removed. Similarly, when the supply roller is driven to rotate in the reverse direction for a predetermined time, the toner adhering to the developing roller can be removed. Therefore, the toner remaining on the developing roller or the like is efficiently removed by the rotation of the regulating roller or the supply roller after the development is completed, and the toner caught even when the regulating roller or the supply roller is stopped thereafter can be suppressed. Problems such as sticking can be effectively prevented. As a result, problems at the time of development due to toner sticking can be resolved, and stable development can be constantly maintained.

Further, in order to achieve the above-mentioned object, the developing device of the present invention rotates the regulating roller and the developing roller in the direction opposite to the direction of the developing operation at the end of the development for a predetermined time. Thus, the problem that the remaining toner sandwiched between the regulating roller and the supply roller and the developing roller is fixed can be solved. That is, the toner remaining on the developing roller due to the rotation of the regulating roller and the supply roller is efficiently removed, and the intervening toner is suppressed. Can be maintained for a period.

In the developing device having the above-described configuration, the control section controls the supply of the same bias voltage to the regulating roller or the supply roller as that at the time of development, after developing the electrostatic latent image, and By performing the stop control of the supplied developing bias voltage, it is possible to remove the toner adhering to the developing roller while maintaining the toner in the direction of pushing the toner from the regulating roller or the supply roller side to the developing roller side. Therefore, the toner remaining on the regulating roller and the supply roller can be moved to the developing roller and removed efficiently, so that the effect of eliminating the intervening toner and eliminating the problem of toner sticking can be promoted.

In the developing device having the above-described configuration, it is preferable that the predetermined time is set to a time during which the regulating roller or the supply roller makes at least one rotation.
Alternatively, in the developing device having the above-described configuration, it is preferable that the predetermined time is set to a time during which at least one rotation of both the regulating roller and the supply roller is performed.

That is, as the predetermined time during which the regulating roller and the supply roller are driven to rotate in the reverse direction, the roller adheres to the regulation roller and the supply roller by being rotated at least once, and when the roller is pressed against the developing roller, the pressure is reduced. The toner is also removed together with the toner on the developing roller side. Therefore, the toner adhering to the regulating roller and the supply roller is also removed, and the toner pinched between the developing roller and the developing roller is eliminated, so that the problem of toner sticking can be more effectively solved. If the predetermined time for the reverse rotation driving is set to a time for about 5 to 6 rotations, the effect is further enhanced. This is as described in the following embodiment.

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings. One embodiment of the developing device of the present invention will be described with reference to FIGS. FIG. 1 is a diagram including a control circuit portion relating to a voltage supply control and a drive control to the developing device according to the present invention, and FIG. 2 is a control procedure by the developing device of the present invention shown in FIG. Showing a control flowchart of
FIG. 3 is a timing chart, and FIG. 4 is a configuration diagram for schematically explaining the structure of the developing device according to the present invention. FIG. 5 is a schematic configuration diagram illustrating an example of an image forming apparatus including the developing device of the present invention.

First, a schematic configuration of the image forming apparatus will be described with reference to FIG. Reference numeral 1 denotes a photoconductor which is arranged at a substantially central portion of the main body of the image forming apparatus, and which forms an image carrier for carrying an electrostatic latent image formed in a drum shape which is driven to rotate at a constant speed in the direction of an arrow during an image forming operation. It is. Various image forming process means are arranged around the photosensitive member 1 so as to face each other.

Means (apparatus) constituting the image forming process include a charger 2 for uniformly charging the surface of the photosensitive member 1, an optical system for irradiating an image 3 with light corresponding to an image (not shown), and an exposure system using the optical system. The developing device 4 according to the present invention for visualizing the electrostatic latent image formed on the surface of the photoreceptor 1 by performing the process, a sheet-shaped sheet to which the developed image (image of the toner 10) is appropriately conveyed Transfer device 5 for transferring the image onto paper P, residual developer (toner) not transferred to the surface of photoconductor 1 after transfer
A cleaning device 6 for removing the toner, a static eliminator 7 for removing the charged charges remaining on the surface of the photoconductor 1, and the like are arranged in this order in the rotation direction of the photoconductor 1.

A large number of sheets P are stored in, for example, a tray or a cassette, and the stored sheets are fed one by one by a feeding means, and are opposed to the photosensitive member 1 on which the above-described transfer device 5 is disposed. Is transferred to the transfer region where the toner image formed on the surface of the photoconductor 1 coincides with the leading end of the toner image. The sheet P after the transfer is peeled off from the photoreceptor 1 and the fixing device 8
Is sent to

The fixing device 8 fixes the unfixed toner image transferred onto the sheet as a permanent image.
A surface facing the toner image is formed of a heat roller heated to a temperature at which the toner is melted and fixed, and a pressure roller or the like is provided which is pressed against the heat roller and closely adheres the paper P to the heat roller side. It is composed. The sheet P that has passed through the fixing device 8 is discharged to a discharge tray (not shown) via a discharge roller outside the image forming apparatus.

If the image forming apparatus is a copying machine, the optical system (not shown) irradiates a copy original with light and irradiates light reflected from the original as a light image 3. Alternatively, if the image forming apparatus is a printer or a digital copier, the optical system emits a light image obtained by driving a semiconductor laser ON-OFF according to image data. Particularly in digital copiers, image data obtained by reading reflected light from a copy original with an image reading sensor (CCD element, etc.) is input to an optical system including the semiconductor laser, and an optical image corresponding to the image data is output. I am trying to do it. In the printer, the light is converted into an optical image corresponding to image data from another processing device, for example, a word processor or a personal computer, and is irradiated. This conversion into an optical image uses not only a semiconductor laser but also an LED element, a liquid crystal shutter and the like.

As described above, when the image forming operation in the image forming apparatus is started, the photosensitive member 1 is driven to rotate in the direction of the arrow, and the surface of the photosensitive member 1 is uniformly charged to a specific polarity by the charger 2. You. After this charging, the optical image 3 is irradiated by the above-described optical system (not shown), and an electrostatic latent image corresponding to the optical image is formed on the surface of the photoconductor 1. The electrostatic latent image is developed by the next developing device 4 in order to visualize the electrostatic latent image. In the present invention, the development is performed using a one-component toner, and is performed by selectively adsorbing the toner to an electrostatic latent image formed on the surface of the photoconductor 1 by, for example, an electrostatic force.

The toner image on the surface of the photoreceptor 1 thus developed is electrostatically transferred onto a sheet P conveyed in synchronization with the rotation of the photoreceptor 1 by a transfer unit 5 disposed in a transfer area. Transcribed. In this transfer, the transfer device 5 charges the back surface of the sheet P with the polarity opposite to the charging polarity of the toner, thereby transferring the toner image to the sheet P side.

After the transfer, a part of the untransferred toner image remains on the surface of the photoconductor 1, and the residual toner is removed from the surface of the photoconductor 1 by the cleaning device 6.
The surface of the photoreceptor 1 is neutralized by the neutralizer 7 to a uniform potential, for example, substantially zero potential in order to reuse.

On the other hand, the sheet P after the transfer is separated from the photoreceptor 1 and is conveyed to the fixing device 8. This fixing device 8
Then, the toner image on the sheet P is melted and pressed and fused to the sheet P by the pressing force between the rollers. This fixing device 8
Is discharged as an image-formed sheet P to a discharge tray or the like provided outside the image forming apparatus.

(Developing Apparatus According to the Present Invention) Next, the structure of the developing apparatus according to the present invention will be described with reference to FIG. That is, a configuration example of the developing device using one-component toner of the present invention will be described in detail.

Referring to FIG. 4, the structure of the developing device for developing with one-component toner will be described.
Is provided with a developing roller 41 rotatably in a developing tank 40 containing a one-component toner, for example, a non-magnetic one-component toner 10, and a supply roller 42 for supplying the one-component toner 10 to the developing roller 41 side. On the right side in FIG. 40, a screw roller 9 for feeding the one-component toner 10 to be replenished as needed into the developing tank 40 is provided.

The developing roller 41 provided in the developing tank 40 has a developing area 41 which is partially exposed and conveys the toner to the above-described developing area which faces the photoconductor 1. Are provided to be rotated in the same direction. The supply roller 42 described above is pressed against the development roller 41 at a position opposite to the development area.

The developing roller 41 has a structure in which, for example, the surface of a metal roller (including a rotating shaft) is coated with a porous elastic material such as a sponge. If an elastic body such as a sponge is made of a polymer foamed polyurethane or the like in which carbon is dispersed, or an ion conductive solid rubber is used, a predetermined resistance value that does not cause toner fusion or the like can be maintained. , As described later, it works effectively when the developing bias voltage is supplied.

A drive motor (not shown) is connected to the developing roller 41, and the developing roller 41 is driven to rotate in the direction of the arrow (counterclockwise) in the figure. The one-component non-magnetic toner 10 is attracted to the surface of the rotating developing roller 41 and is conveyed to a developing area facing the surface of the photoconductor 1. Since the developing roller 41 is pressed against the surface of the photoreceptor 1, the pressed area is a developing area,
The one-component toner 10 is attracted to the electrostatic latent image on the surface of the photoconductor 1 and is developed.

The one-component toner 10 is, for example, a one-component non-magnetic toner having an average particle diameter of about 10 μm, and a polyester toner or a styrene acrylic toner is used. This toner diameter is an example, and when high resolution (600 dpi or 1200 dpi) development is performed, a toner having an average particle diameter of 8 μm, 6 μm, or a smaller diameter is used.

The developing roller 41 is supplied with a developing bias voltage Va from the developing bias power supply circuit 11. The developing bias voltage Va is set to a polarity and a voltage value so that toner adheres to the electrostatic latent image formed on the photoconductor 1 and toner does not adhere to other areas, that is, non-image areas.

The supply roller 42 rotates in a direction opposite to the developing roller 21 (pressure contact area).
Is driven to rotate in a direction opposite to the rotation direction.
The supply roller 42 uses the same material as the developing roller 41, and the electric resistance can be adjusted with the same resistance adjusting material as the developing roller 41. In order to further increase the elasticity of the supply roller 42, a foamed material is used, and a foaming agent having a larger amount than the developing roller is used.

A bias voltage Vc is applied to the supply roller 42 from the bias power supply circuit 12, and is generally in the direction of pushing (moving) the toner toward the developing roller 41, that is, the toner on the supply roller 42 side. And a bias voltage value in a direction in which the bias voltage is supplied to the developing roller 41. For example, when a negative polarity toner is used, a larger bias voltage Vc is applied to the negative polarity side of the supply roller 4.
2 is applied.

The developing roller 41 and the supply roller 42 are connected to a drive motor (not shown), and are driven to rotate in the direction of an arrow (counterclockwise) in the figure, whereby toner is supplied to the development roller 41 by the supply roller 42. At the same time, the residual toner on the surface of the developing roller 41 that has not contributed to the development after the development is scraped off (removed). The toner 10 supplied by the supply roller 42 is
Before being conveyed to the developing area opposed to the surface of the photoreceptor 1 and conveyed to the surface of the photoreceptor 1, a regulating roller 43, which is a member for appropriately regulating the amount of toner adhered to the developing roller 41,
The amount of toner adhered is regulated to a constant toner layer thickness.

The regulating roller 43 is pressed against the developing roller 41 with an appropriate pressure. The regulating roller 43 is rotationally driven in the same direction as the developing roller 41 so as to rotate in the opposite directions at a position where the regulating roller 43 contacts the developing roller 41. The regulating roller 43 has a hard roller configuration made of a metal material, a hard resin material, or the like. The regulating roller 43 receives a predetermined charge from the bias power supply circuit 13 in order to set the toner 10 preliminarily charged by the supply roller 42 to a desired charge amount. Is supplied. Even at this bias voltage Vb, the toner 1
In the direction in which 0 is pushed toward the developing roller 41, for example, a larger value is set on the negative polarity side for negative polarity toner. Also, the bias voltage Vb supplied to the regulating roller 43
Is a developing bias voltage Va supplied to the developing roller 21.
It is set to a larger value in absolute value.

On the other hand, the toner 10 conveyed to the developing area opposed to the photoreceptor 1 is selectively adhered according to the electrostatic latent image formed on the surface of the photoreceptor 1, and the electrostatic latent image is transferred to the toner color. To visualize. Then, the toner 10 that has not contributed to the development is returned into the developing tank 40 by the rotation of the developing roller 41. At the return position, a toner sealing member 44 is provided so as to be pressed against the developing roller 41. The seal member 44 is disposed downstream of the developing roller 41 after development in the rotation direction and before pressing against the supply roller 42, and has one end fixed to the developing tank 40 so as to appropriately press against the developing roller 41. The antinode of the free end is pressed against the developing roller 41 by utilizing a spring property having a region to be pressed against the developing roller 41.

The developing device 4 configured as described above conveys the toner 10 to a region facing the photoconductor 1 and visualizes the latent image on the surface of the photoconductor 1 with the toner. This photoconductor 1
The toner image on the front surface is transferred to the sheet P appropriately conveyed in the transfer area by the operation of the transfer device 5 as described above,
The sheet passes through the fixing device 8 and is discharged out of the image forming apparatus.

The photoreceptor 1 has an underlayer coated on the surface of a metal or resin conductive substrate, a carrier generation layer (CGL) as a layer thereon, and a carrier containing polycarbonate as a main component on the outermost layer. An OPC photoreceptor formed by applying a moving layer (CTL) is used. In the present invention, the present invention is not limited to such a photoreceptor, but may be any carrier that carries an electrostatic latent image.

Hereinafter, features of the present invention, that is, an embodiment of the developing device 4 of the present invention will be described in detail with reference to FIGS.

(Embodiment of the Invention) The developing roller 41
As described above, a specific example of the structure will be described in detail. The developing roller 41 has a diameter of, for example, 18 m.
m with a conductive agent such as carbon black added to a stainless steel rotating shaft with a volume efficiency of about 10 ⁶ Ωcm, JI
Conductive urethane rubber having an SA hardness of 60 to 70 degrees has a diameter of 3
4 mm, and the surface roughness Rz = 3 to
6 μm (according to JISB-0601). The developing roller 41 is pressed against the photosensitive member 1 with a contact depth of 0.1 mm to 0.3 mm via the toner layer, and is rotationally driven in a direction indicated by an arrow in FIG. The driving of the developing roller 41 is controlled at a peripheral speed of 285 mm / sec. These are merely examples and are not limiting.

The developing bias voltage Va of the developing bias power supply 11 supplied to the rotating shaft of the developing roller 41 is related to the charging potential of the photosensitive member 1 when the charging characteristic of the one-component toner is, for example, negative. For example, it is set to -350V.

Next, the supply roller 42 also has a function of stirring the toner in the developing tank 40 and removing the residual toner after the development by the developing roller 41 from the developing roller 41. The supply roller 42 is configured such that its rotating shaft is covered with a conductive porous foam member.

The porous foam has a volume efficiency of about 10 ⁵ Ωcm and a porous cell density of 80 to 140.
It is made of a conductive urethane foam having an Asuka F hardness of 60 to an Asuka C hardness of 30 degrees. This polyurethane foam is mixed with carbon black in an amount of 5 to 15 parts by weight, and in some cases, about 70 parts by weight based on 100 parts by weight of the foam. The same polyurethane foam and carbon black as those used for the developing roller 41 are used.

In order to obtain a foam which forms the above-mentioned cell density, for example, a polyurethane foam and carbon black are mixed, stirred by a whisk, whisked, and heated by blow molding to form a stainless steel rotary shaft having a diameter of 8 mm. A supply roller 42 is formed by coating the periphery with a diameter of 20 mm.

The supply roller 42 is pressed against the developing roller 41 to a contact depth of about 0.5 mm to 1 mm, and is driven, for example, at a peripheral speed of 17 by a drive motor (not shown) in the direction of the arrow.
It is driven to rotate at 0 mm / sec. The supply roller 42 is supplied with a voltage Vc (for example, −500 V) from the toner supply bias power supply 12 to the rotating shaft.

Further, the regulating roller 43 is rotated as shown in FIG. 4, and is pressed against the developing roller 41 with an appropriate pressure. As a result, the toner is frictionally charged, a charge suitable for development is applied to the toner, and the amount of adhesion to the developing roller 41 is regulated at the same time.

The regulating roller 43 is made of, for example, a metal material or a hard resin material. In addition, the regulating roller 43
Has a diameter of about 10 mm, and
4, that is, in a counterclockwise direction in FIG. 4, for example, at a speed of 90 mm / sec, and the amount of toner on the developing roller 41 supplied by the supply roller 42 is, for example, about 10 to 15 μm as a toner layer thickness. To be regulated. Similarly, a regulation bias voltage Vb (−450 V) for regulating the toner layer is supplied to the roller shaft of the regulation roller 43 from the toner layer thickness regulation bias power supply 13.

The toner which is a non-magnetic one-component developer used in the present invention will be described below. This one-component toner is prepared by mixing, kneading, and pulverizing a material having a composition of 80 to 90 parts by weight of a styrene-acryl copolymer, 5 to 10 parts by weight of carbon black, and 0 to 5 parts by weight of a charge controlling agent. By performing classification, a negatively charged toner having an average particle size of about 5 to 10 μm can be obtained. For this toner, silica (Si) added internally or externally to improve fluidity
O ₂ ) is added in an amount of 0.5 to 1.5 parts by weight to obtain a non-magnetic one-component toner.

The toner is not limited to the negative charge, but may be a positively charged toner. This can be easily obtained by appropriately selecting a binder resin, a charge control agent, and the like as main components. Further, the toner is not covered with black toner for monochrome copying machines and printers, but can be applied to color toners for color copying machines and printers.

The non-magnetic one-component toner is not limited to the above-mentioned composition material, and can be used in the developing device of the present invention even if it has the following composition.

The thermoplastic resin, which is the binder resin as the main component, may be polystyrene, polyethylene, polyester, low molecular weight polypropylene, epoxy, polyamide, polyvinyl butyral, etc., in addition to the styrene-acrylic copolymer.

As a coloring agent, in the case of a black toner, besides using the above-described carbon black, there are furnace black, nigrosine dyes, metal-containing dyes and the like. For color toners, benzidine yellow pigment for yellow, phonon yellow, anilide acetoacetate insoluble azo pigment, monoazo pigment, azomethine dye, etc., xanthene magenta dye for magenta, phosphotungsten molybdate lake pigment, anthraquinone Dyes, coloring materials comprising xanthene dyes and organic carboxylic acids, thioindigo, naphthol-based insoluble azo pigments, and the like, and copper phthalocyanine-based pigments for cyan.

Further, in addition to, for example, silica as an external additive used as a fluidizing material of the toner, colloidal silica, titanium oxide, alumina, zinc stearate, polyvinylidene fluoride, and a mixture thereof may be used.

Further, as the charge control agent, azo-based metal-containing dyes, organic acid metal complex salts, chlorinated paraffins and the like can be used for negatively charged toners. For positively charged toners, nigrosine dyes, fatty acid metal salts, amines, quaternary ammonium salts, and the like can be used.

In the developing device 4 using the one-component toner as described above, the adhesion amount of the toner 10 is regulated by the regulating roller 43 pressed against the developing roller 41 so as to have a constant layer thickness. After that, the toner 10 is transported to the developing area to develop the electrostatic latent image on the surface of the photoconductor 1. At this time, the bias voltages Va, Vb, and Vc are supplied to the developing roller 41, the supply roller 42, and the regulating roller 43, respectively, so that good development is performed.

The photoreceptor 1 has a photosensitive layer made of a negatively charged organic material formed on the surface of a drum-shaped conductive substrate, and has a diameter of, for example, 65 mm and a peripheral speed of 190 mm / sec in the direction of the arrow in FIG. Is driven to rotate. The photosensitive member 1 is uniformly charged to a surface potential of, for example, about -550 V by the charger 2 in FIG.

(One Control Example of Developing Device According to the Present Invention) In the developing device 4 of the present invention, the developing roller 4 shown in FIG.
1. The rotation drive of the supply roller 42 and the regulation roller 43 and the control of the supply of the bias voltage are controlled by the control unit 50 that controls the entire drive of the image forming apparatus main body described with reference to FIG. The control unit 50 causes the power supply circuits 11 to 13 to supply the respective bias voltages to the respective rollers in the developing device illustrated in FIG. 4 via a power supply control circuit (bias voltage control circuit) 51. In order to control the driving of the developing roller 41, the supply roller 42, and the regulating roller 43, a rotation drive control circuit 52
, And controls to form an image, including the control of various process units shown in FIG.

According to the present invention, when the developing device 4 is driven, a predetermined bias voltage is supplied via each of the power supply circuits 11, 12, and 13, as described above, at the time of development, as in the prior art. The electrostatic latent image formed on the body 1 is visualized with toner. Accordingly, the control unit 50 forms an electrostatic latent image on the photoconductor 1 by driving the rotation of the photoconductor 1 and driving the charger and the like in response to the image forming command, and exposing the light image.

Next, the electrostatic latent image is developed by the developing device 4. Therefore, the control unit 50 rotates the developing roller 41 via the drive control circuit 52. At the same time, the supply roller 42 and the regulation positive roller 43 are driven to rotate in the direction of the arrow in FIG. Thereby, the developing roller 41 is regulated to a certain amount of toner layer thickness, and the regulated toner is conveyed to the developing area. The control unit 50 controls the supply roller 42 and the regulating roller 43 so that a certain amount of toner layer is formed.
Is rotated in the direction shown in the figure, and the power supply control circuit 51 is controlled so that the determined bias voltage is supplied from the respective power supply circuits 11 to 13.

As described above, when the image forming operation is sequentially performed and all the developing operations are completed, the control unit 50 controls the developing device 4 to stop the developing process. In this case, in the present invention, the control flowchart of FIG.
Is executed according to the timing chart of FIG. That is, in the present invention, after developing the final area of the electrostatic latent image, the toner as the developer adhered to the developing roller 41 is efficiently removed. Eliminates toner that is pinched and prevents toner from sticking.

In particular, in the developing device 4 of the present invention, as shown in FIG. 4, when the developing operation is started, the developing roller 41 is driven to rotate in one direction indicated by an arrow. On the other hand, the regulating roller 4 pressed against the developing roller 41
3. The supply roller 42 is configured to be rotatable forward and backward by driving means, for example, a driving motor. Then, in the developing operation, it is rotationally driven in the direction shown in FIG. 4 (forward rotation direction). However, as described below, when the developing operation is completed, the image forming apparatus is configured to be rotationally driven in the reverse direction for a predetermined time.

Therefore, before explaining the control before and after the end of the developing operation according to the present invention, a conventional control example is shown in FIG.
This will be described with reference to FIG. As shown in FIG. 3D, the developing operation is performed by the image forming operation as described above,
When the developing operation is completed, the rotation of the developing roller (developer carrier) 41 is stopped, and the rotation of the toner supply roller 42 and the regulating roller 43 is also stopped (OFF) accordingly.

Then, the developing roller 41 and the supply roller 4
The supply of the developing bias voltage Va, the bias voltage Vc of the supply roller 42, and the supply of the bias voltage Vb of the regulating roller 43 are shut off (OFF) via the power supply control circuit 52 in synchronization with the stop of the rotation of the second roller 2.

For this reason, the toner remains on the developing roller 41 between the supply roller 42 and the regulating roller 43, and is in a state of being pressed against and waiting. This allows
The toner may be adhered at that portion. If the developing operation is started due to the adhesion of the toner, the toner layer cannot be made uniform by the regulating roller 43, and a developing defect may occur. In addition, the charging of the toner cannot be performed satisfactorily, resulting in the development failure being promoted.

On the other hand, according to the present invention, the developing device 4
Is performed, and when the developing operation is completed, the operation control of the developing device is executed via the control unit 50 shown in FIG. 1 in response thereto. The processing procedure is as shown in FIG. 2, and its timing chart is shown in FIG.
(A). The example described below is for preventing the toner interposed between the developing roller 41 and the regulating roller 42 from sticking.

That is, in the image forming apparatus of the present invention,
The image forming operation is started, and then the developing operation of the developing device 4 is started (S1). Then, the developing process of the electrostatic latent image on the photoconductor 1 is completed, and the photoconductor 1 passes through the transfer position, the cleaning position, and the position where the residual charge remaining on the photoconductor 1 is removed, and the entire circumference of the photoconductor 1 is removed. Is stopped, the rotation of the developing roller 41 is stopped, and the rotation of the developing roller 41 is terminated.

When it is confirmed that the above-described developing operation is completed (S2), the rotation of the developing roller 41 is stopped (S3) so as to coincide with the stop of the rotation of the photosensitive member 1. The control unit 50 controls the rotation stop of the developing roller 41 and, at the same time, controls the supply stop of the developing bias voltage Va (S3). Further, the control unit 50 stops the developing roller 41,
And the supply stop control of the developing bias voltage Va, the rotation of the supply roller 43 is stopped, and the bias voltage V
The supply stop control of c is executed. This is as shown in the timing chart of FIG.

On the other hand, in accordance with the control described above, the control unit 50 temporarily stops the rotation of the regulating roller 43 in the reverse direction to drive the rotation in the reverse direction.
That is, drive control is performed to reverse the rotation direction. This reversal is a clockwise rotation opposite to the rotation direction of the regulating roller 43 shown in FIG.
Run one. At this time, the supply of the bias voltage Vb supplied to the regulating roller 43 is continuously maintained (S4).

As described above, under the control of the control unit 50, the drive control circuit 52 controls the developing roller 41 and the supply roller 42.
Is stopped, and the rotation of the regulating roller 43 is controlled in the reverse direction. Moreover, the power control circuit 51
Bias voltage V of developing roller 41 and supply roller 42
a and Vc to stop the supply and maintain and supply the bias voltage Vb to be supplied to the regulating roller 43.
Only operate.

Then, it is confirmed whether or not the predetermined time t1 has elapsed (S5). If the predetermined time t1 has elapsed, stop control of the regulating roller 43 driven in reverse rotation and stop of the supply of the bias voltage Vb are performed. (OFF) The control (S6) is executed, and the operation is completed.

By executing the control by the developing device 4 as described above, especially the regulating roller 43 and the developing roller 4 are controlled.
It is possible to prevent the residual toner that is interposed, including during standby and the like, from being fixed at the pressure contact portion with the first fixing member. The operation of the present invention that can prevent this will be described below.

In the developing device 4, during the developing process, that is, during the operation of developing the electrostatic latent image, at least the developing roller 41 and the supply roller 42 are rotationally driven in the respective directions. Bias voltage is supplied. For example, in the example described above, the developing roller 41
350V is supplied to the supply roller 43, and -500V is supplied to the supply roller 43.

In the relation of the bias voltage during the developing operation, the negatively charged toner is pushed to the developing roller 41 side. In other words, the developing roller 4
1 acts to attract the toner. Then, as shown in FIG. 6A, the amount of the toner 10 adhering to the developing roller 41 by the regulating roller 43 (the amount of application)
Is regulated, and the electrostatic latent image is transported to a developing area where the electrostatic latent image is developed. In such an operation state, the toner 10 is nipped between the rollers 41 and 43 and is not maintained for a long period of time, so that the toner 10 does not stick. That is, during the developing operation, there is no problem such as toner sticking.

When the developing process of the electrostatic latent image is completed and the developing operation by the developing device 4 is completed, the rotation of the developing roller 41 is stopped, and the regulating roller 43 is instantaneously rotated for reversal driving. Stops. Figure 6 shows this state.
This is shown in FIG. At this time, the toner 10 is held between the developing roller 41 and the regulating roller 43. Moreover, due to the bias voltage and the like, the acting force of the toner 10 to be further drawn toward the developing roller 41 is increased.

As described above, the potential difference due to the bias voltage is
In addition to the fact that it has become larger,
As shown in FIG. 6C, the rotation direction of the regulating roller 43 is reversed (reverse rotation) from that during the developing operation, and the developing roller 41 is rotated.
The toner 10 attracted to the side
Is scraped off (swept out). This operation is performed for a predetermined time t1 from the time when the developing operation is completed, and the toner 10 that is going to be interposed between the developing roller 41 and the regulating roller 43 is efficiently removed. Then, after the predetermined time t1, the supply of the bias voltage Vb is stopped simultaneously with the stop of the rotation of the regulating roller 43.

Therefore, until the predetermined time t1 elapses,
After the toner adhering to the surface of the developing roller 41 is effectively scraped off the toner on the side of the developing roller 41 due to the action of the electric field due to the potential difference, and after the regulating roller 43 is stopped, the developing roller 41 and the regulating roller 43 In this case, the cause of the problem such as toner sticking is eliminated, and toner sticking can be prevented.

Further, the developing operation is completed, the regulating roller 43 is driven to reverse, and is continuously rotated for a predetermined time. It is preferable that the predetermined time t1 is set to a time that requires at least one rotation of the regulating roller 43 with reference to the end point of the development. In other words, by making one or more rotations, the toner on the regulation roller 43 side is moved in the direction of the developing roller 41, which can be effectively removed by reversal driving, and the toner adhered to the entire periphery of the regulation roller 43 is effectively removed it can. Optimally, the predetermined time t is set to the time required for the regulating roller 43 to make 5-6 rotations.
By setting 1, the problem of toner sticking can be almost completely prevented.

As described above, the developing device 4 of the present invention
In the above, the bias voltage Vb supplied to the regulating roller 42 is maintained as it is for a predetermined time t1 from the point of time when the development is completed, and the rotation direction is reversed, so that the relationship between the potential difference with the development roller 41 and the toner Roller 4
The force acting on the control roller 43 is strengthened to effectively remove the toner 10 interposed between the control roller 43 and prevent the toner from remaining between the developing roller 41 and the control roller 43 when stopped. In addition, it is possible to effectively prevent toner from sticking.

According to the above-described embodiment of the present invention, the negatively charged toner has been described as an example of the toner. However, when the positively charged toner is used, the bias supplied to the developing roller 41 and the supply roller 43, etc. The voltage may be positive.

In the description of the timing chart of FIG. 3A and the above description, the bias voltage supplied to the regulating roller 42 is maintained as it is for a predetermined time t1 from the end of the developing operation. By stopping the supply of the bias voltage Va supplied to the developing roller 41,
The potential difference between the developing roller 41 and the developing roller 41 is 50 in the above-described example.
When the voltage becomes 0 V and becomes equal to or higher than the discharge starting voltage, the discharge is started. It is also conceivable that the toner is melted by the heat due to this discharge, which promotes problems such as sticking. To prevent this, the switching control may be performed by lowering the bias voltage Vb supplied by the regulating roller 43 to, for example, about -300 V which is lower than the discharge start voltage. Even if you do this,
The potential difference can be made larger than the potential difference at the time of development, and the force for attracting the toner toward the developing roller 41 increases.

(Another Aspect According to the Embodiment of the Present Invention) According to the above-described embodiment of the present invention, the problem of toner sticking to the developing roller 41 between the developing roller 41 and the regulating roller 43 is solved. It was explained as a thing for.

However, not only the problem of toner sticking between the developing roller 41 and the regulating roller 43 due to the rotation stop at the end of the development occurs.
That is, even with the supply roller 42 that actively supplies the toner to the developing roller 41, the stop control in response to the end of the developing operation causes the toner 10 to intervene, thereby causing a problem of toner sticking.

An example of solving the problem of toner sticking to the supply roller 42 will be described below. FIG. 3 shows an example of a control procedure of the developing device related to the supply roller 43 in FIG. 7, and a timing chart in the control procedure is shown in FIG.
This is shown in FIG.

A description will be given below with reference to these figures. 7, the same control steps as those in the control procedure shown in FIG. 2 are described in the same steps, and the description thereof will be omitted.

The developing device 4 performs an image forming operation, in particular, the photosensitive member 1
The developing roller 41 is normally driven to rotate when the photosensitive member 1 starts rotating. When the developing operation is performed and it is confirmed whether or not the developing operation is completed (S2), the supply of the developing bias voltage Va is stopped in synchronization with the stop of the driving of the developing roller 41 (S3).

At the end of the developing operation, the processing from step S41 in FIG. That is, the control unit 50 temporarily stops the rotation of the supply roller 42 in the direction opposite to that during the developing operation, together with the above-described control in accordance with the end of the development, and temporarily stops the rotation of the supply roller 42 with the current rotation direction. Drive control is performed so as to reverse the reverse direction, that is, the rotation direction. The inversion drive control is continued for a predetermined time t2, which will be described in detail later.
At this time, the supply of the bias voltage Vc supplied to the supply roller 42 is continuously maintained (S41).

As described above, under the control of the control unit 50, the drive control circuit 52 controls the developing roller 41 and the supply roller 42.
Is stopped, and the rotational direction of the supply roller 43 is rotationally controlled in the reverse direction. Moreover, the power control circuit 51
Bias voltage V of developing roller 41 and regulating roller 43
a and Vb to stop the supply and maintain and supply the bias voltage Vb to be supplied to the supply roller 42.
Only operate.

Then, it is confirmed whether or not the predetermined time t2 has elapsed (S51). If the predetermined time t2 has elapsed, stop control of the regulating roller 42 driven in reverse rotation and stop of the supply of the bias voltage Vc are performed. (OFF) control (S61) is executed, and the operation is completed.

Referring to the timing chart of FIG. 3B, at the end of the developing operation, the rotation of the developing roller 41 and the regulating roller 43 and the supply of the bias voltage are stopped. Then, at the end of the developing operation, the supply roller 42 that supplies toner is momentarily stopped for reverse driving, and the motor and the like are reversely excited to perform reverse rotation driving. This drive is continued for a predetermined time t2.
At this time, the bias voltage Vc supplied to the supply roller 42 is maintained as it is.

By executing the control by the developing device 4 in this manner, it is possible to prevent the residual toner interposed in the pressure contact portion between the supply roller 42 and the developing roller 41, including during standby, from being fixed. . The function of the present invention that can prevent this is the same as that of the regulating roller 43. As described with reference to FIG. By the reverse rotation of 42, the toner is removed and toner sticking can be effectively prevented.

That is, in the relation of the bias voltage during the developing operation, the negatively charged toner acts so as to be attracted to the developing roller 41 side, and the action acts more strongly after the development is completed. In addition, the rotation of the supply roller 42 is reversed with respect to the time of development, and the toner 10 drawn toward the developing roller 41 is scraped off by the supply roller 42. This operation is performed for a predetermined time t2 from the time when the developing operation is completed, and the toner interposed between the developing roller 41 and the supply roller 42 is efficiently removed. After the predetermined time t2, the supply of the bias voltage Vb is stopped at the same time as the rotation of the regulating roller 43 is stopped.

Therefore, until the predetermined time t2 elapses,
After the toner adhering to the surface of the developing roller 41 is effectively scraped off by the action of the electric field due to the potential difference, the toner on the developing roller 41 side is stopped, and after the supply roller 42 is stopped, the developing roller 41 and the supply roller 42 In this case, there is no toner, and the toner can be prevented from sticking.

The developing operation is completed, the supply roller 42 is driven to reverse, and the supply roller 42 is continuously rotated for a predetermined time. It is preferable that the predetermined time t2 is set to a time during which the inversion of the supply roller 42 makes at least one rotation with respect to the end point of the developing operation. In other words, by one rotation, the toner on the supply roller 42 side is moved in the direction of the developing roller 41, and this can be effectively removed by reversing drive, and the toner adhering to the entire circumference of the supply roller 42 can be effectively removed. . Optimally, supply roller 43 is 5
By setting the predetermined time t2 to a time that allows up to six rotations, the problem of toner sticking can be almost completely prevented.

(Another Aspect According to First Embodiment of the Present Invention) According to the above-described embodiment and other examples of the present invention, toner fixation between the developing roller 41 and the regulating roller 43 is performed. Alternatively, it has been described that the toner is fixed between the image roller 41 and the supply roller 42.

Accordingly, an example will be described below in which both the regulation roller 43 and the supply roller 42 are prevented from sticking toner to the developing roller 41 at the same time. The problem of toner sticking, which is the subject of the present invention, that is, the developing operation
When the developing roller 41 is stopped and controlled, if the toner 10 remains in the respective pressure contact areas at the position of the regulating roller 43 and the supply roller 42 in the developing tank 40, the toner is stuck by the pressing action. Occurs. This phenomenon becomes more conspicuous as the roller is strongly pressed against the developing roller 41. Once the toner is fixed, the fixed toner is hard to be removed, and the above-described problem occurs.

Therefore, as another aspect according to the embodiment of the present invention, an example in which the problem of toner sticking in a region where the regulating roller 43 and the supply roller 42 are in pressure contact with the developing roller 41 will be described below.

FIG. 8 shows an example of a control flowchart for solving the problem of toner sticking in the pressure contact area between the supply roller 42 and the regulating roller 43 pressed against the developing roller 41. FIG. 3C is a timing chart corresponding to the control procedure of the developing device in FIG.
Is shown in

In particular, according to FIG. 8, in the control shown in FIGS. 2 and 7, that is, in the processing after step S3, steps S4, S5, S6 in FIG. 2 and step S4 in FIG.
1, the processing of S51 and S61 is performed collectively.

Therefore, the developing device 4 operates in accordance with the image forming operation, in particular, the rotation of the photosensitive member 1, and the developing roller 4
1 is normally driven to rotate when the photoconductor 1 starts rotating.
When the developing operation is performed and it is confirmed whether or not the developing operation is completed (S2), the supply of the developing bias voltage Va is stopped in synchronization with the stop of the driving of the developing roller 41 (S2).
3) The control described below is executed.

First, the regulating roller 43 and the supply roller 42
To temporarily stop the rotation of the
Drive control is performed to reverse the direction of rotation up to now, that is, to reverse the direction of rotation with the rotation during the developing operation. And
This inversion drive control is performed for a predetermined time t, as described above.
One or t2 is continued. At this time, the bias voltages Vb and Vc supplied to the regulating roller 43 and the supply roller 42 are
Is continuously maintained (S42).

As described above, under the control of the control unit 50, the drive control circuit 52 stops the driving of only the developing roller 41 and controls the rotation of the regulating roller 43 and the supply roller 43 in the reverse direction. In addition, the power supply control circuit 51 stops the supply of only the developing bias voltage Va of the developing roller 41 and maintains the supply of the bias voltages Vb and Vc of the regulating roller 43 and the supply roller 42.
Operate 2

Then, as described with reference to FIG. 2, steps S5 and S6 are executed together. That is, it is determined whether or not the predetermined time t1 has elapsed (S5).
Thereafter, the reverse rotation drive of the regulating roller 43 is stopped, and the supply stop control of the bias voltage Vb is executed (S6).

After executing the above-described processing, the processing of steps S51 and S61 described with reference to FIG. 7 is executed. That is, it is confirmed whether or not a predetermined time t2 has elapsed from the end of the developing operation (S51). If the predetermined time t2 has elapsed, the stop control of the regulating roller 42 driven in reverse rotation and the supply of the bias voltage Vc are performed. The stop (OFF) control (S61) is executed, and the operation is completed.

The timing according to the above control is shown in FIG.
This is as shown in the timing chart of FIG. By such control, after the developing roller 41 stops, the toner interposed in the pressure contact portion between the regulating roller 43 and the supply roller 42 and the developing roller 41 is effectively swept, and the problem such as toner sticking is solved. I have. This is as described above, and the details are omitted.

Therefore, until the predetermined times t1 and t2 have elapsed from the end of the development, the toner adhering to the surface of the developing roller 41 may be interposed between the developing roller 41 and the electric field due to the potential difference. After the developing toner is efficiently scraped off (swept out) and the regulating roller 43 and the supply roller 42 are stopped, there is no toner between the developing roller 41 and the regulation roller 43 and the supply roller 42, and the toner adheres. Can be prevented.

The above-mentioned predetermined times t1 and t2 are as described above, and are set at a time during which the regulating roller 43 and the supply roller 42 are driven to rotate in the reverse direction by at least one or more rotations from the time when the stop of the developing roller 41 is controlled. Yes, preferably 5
The time is set to about six rotations.

Accordingly, in the flowchart of FIG. 8, it is determined that the predetermined time t1 is shorter, and the elapse of the time t1 is first confirmed (S5).
2 (S51). In the developing device 4 as shown in FIG. 4, the diameter of the regulating roller 43 is set smaller than the diameter of the supply roller as described above, and the respective rollers 43,
When the peripheral speed of the roller 42 is the same, for example, the time for five rotations is shorter for the regulating roller 42.

The regulating roller 43 and the supply roller 42
The time required for the control roller 43 to make one rotation is shorter than the time required for the supply roller 42 to make one rotation, even when the peripheral speed at the time of the reverse rotation drive is adjusted to the peripheral speed at the time of development.

Therefore, as shown in the control flow of FIG. 8, the stop control of the regulating roller 43 is speeded up, and the stop control of the supply roller 42 is performed later. However, the predetermined time t
1 and t2 do not need to be different and can be set to the same time. This can be adjusted, for example, by increasing the peripheral speed of the regulating roller 43 so that the times of the five rotations coincide.

Alternatively, as another method for making the predetermined time the same, a predetermined number of times, for example, the longer of the five rotation times is set as the predetermined time t. According to the configuration of the above-described embodiment, the predetermined time t1 may be the same as the predetermined time t2 of the supply roller 42 having a long set time. In this case, if the number of rotations of the supply roller 42 is five, the number of rotations of the regulating roller 43 exceeds five. However, if the stop control is performed at the same time, the control is naturally simple, and the drive control may be performed in such a manner.

In the above-described embodiment of the present invention, an example has been described in which the developing roller 41 is provided so as to be in contact with the photosensitive member 1. However, the present invention is not limited to such a device, and is similarly applied to a non-contact type developing device in which the developing roller 41 is arranged at a predetermined distance from the photosensitive member 1. Can be implemented.

[0126]

According to the one-component toner developing device of the present invention, the regulating roller or the supply roller is pressed against the developing roller which carries the toner and conveys the latent image to the developing position of the image carrier. With the roller, it is possible to effectively prevent a problem that toner interposed at the time of stopping the development is fixed to the developing roller, the regulating roller, the supply roller, and the like. As a result, stable supply of toner to the developing roller can be performed for a long period of time, and stable development can be maintained for a long period of time.

In this case, the regulating roller or the supply roller is driven to rotate in the reverse direction during the developing operation for a predetermined time, so that the intervening toner can be effectively removed, and the above-described effect can be expected.

Further, only the state at the time of development is maintained without switching control of the bias voltage and the like supplied to the regulating roller and the supply roller, and troublesome control such as switching can be eliminated.

Therefore, in an apparatus that performs development using a one-component toner, stable development can be maintained at all times, and this can be stabilized for a long period of time. And the non-contact method can be similarly implemented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a control circuit configuration showing an example of a control example for describing an embodiment according to a one-component toner developing device of the present invention.

FIG. 2 is a control flowchart showing a control procedure in the control circuit configuration shown in FIG. 1, particularly a control procedure of a developing device after development is completed.

3 is a timing chart showing control timing according to the control flowchart of FIG. 2, wherein (a) to (c) are timing charts in the present invention, and (d) are timing charts in the related art.

FIG. 4 is a configuration diagram illustrating an internal structure of a one-component toner developing device according to an embodiment of the present invention.

FIG. 5 is a configuration diagram illustrating a schematic configuration of an image forming apparatus including the developing device of the present invention.

FIG. 6 is an explanatory diagram for explaining a toner removing operation according to the embodiment of the present invention.

FIG. 7 is a control flowchart showing a control procedure of a developing device according to another aspect of the embodiment of the present invention.

FIG. 8 is a control flowchart showing a control procedure of a developing device according to another mode according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor (electrostatic latent image carrier) 4 Developing device 10 (Non-magnetic) one-component toner 11 Power supply circuit for supplying developing bias voltage 12 Power supply circuit for supplying voltage to regulating roller 13 Voltage supply to supply roller Power supply circuit 40 developing tank 41 developing roller 42 supply roller 43 regulating roller 50 control unit 51 bias voltage control circuit 52 rotation drive control circuit

Claims (6)

[Claims] A developing roller that carries the one-component toner and transports the toner to a developing area facing the electrostatic latent image carrier; and a step in which the developing roller transports the toner to the developing area before the developing roller transports the toner to the developing area. And a regulating roller that regulates the toner supplied to the developing roller to a fixed amount before reaching the developing area, and the electrostatic latent image of the electrostatic latent image carrier is transferred to the developing area. A developing unit for controlling the rotation of the regulation roller or the supply roller in a direction opposite to the rotation direction at the time of development for a predetermined time after development. 2. A developing roller that carries a one-component toner and conveys the toner to a developing area facing the electrostatic latent image carrier. Before the developing roller conveys the toner to the developing area, the developing roller applies toner to the developing roller. And a regulating roller that regulates the toner supplied to the developing roller to a fixed amount before reaching the developing area, and the electrostatic latent image of the electrostatic latent image carrier is transferred to the developing area. A developing unit for controlling the rotation of the regulation roller and the supply roller in a direction opposite to the rotation direction at the time of development for a predetermined time after development. 3. The control section, after developing the electrostatic latent image,
2. The one-component toner according to claim 1, wherein a supply of a bias voltage equal to that during development is controlled to the regulating roller or the supply roller, and a stop control of the development bias voltage supplied to the development roller is performed. Developing device. 4. The control section, after developing the electrostatic latent image,
3. The one-component toner according to claim 2, wherein a bias voltage equivalent to that at the time of development is supplied and controlled to the regulating roller and the supply roller, and a stop control of the development bias voltage supplied to the development roller is performed. Developing device. 5. The one-component toner developing device according to claim 1, wherein the predetermined time is set to a time during which the regulating roller or the supply roller makes at least one rotation. 6. The one-component toner developing device according to claim 2, wherein the predetermined time is set to a time during which both the regulating roller and the supply roller make at least one rotation. .