JP2002006623A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of suppressing electric power consumption as well as fluctuation of rotational speed of a developer carrier and preventing generation of uneven image density caused by such fluctuation in using a roller-shaped member for regulating developer layer. SOLUTION: The image forming device is equipped with a developing device 5 performing an attachable/detachable operation such that it separates from a photosensitive belt 1 at a non-developing period and that it moves to a developing position where a developing roller 11 comes into a prescribed positional relation with the photosensitive belt 1 before development. A control means for rotating a regulating roller in interlocking with this movement of the developing device 5 which takes place before development, is constituted by using: an oscillating member 20 that is fixedly installed on the rotational axis 14a of the regulating roller and that makes the rotational axis 14a the center of the oscillation; and a guide member that is provided in the body of the image forming device and that guides the oscillating member 20 to oscillation by engaging with the member 20 in interlocking with the moving operation of the developing device before development.

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 a copying machine, a facsimile, and a printer.
A developer-carrying member, and a roller-shaped developer-layer regulating member that abuts on the developer-carrying member and regulates a layer thickness of the developer carried on the developer-carrying member. The present invention relates to an image forming apparatus provided with a developing device that performs a contact / separation operation such that the developer carrier is separated from a carrier and moves to a developing position where a developer carrier has a predetermined positional relationship with a latent image carrier prior to development. .

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus of this type, there are provided a photoconductor as a latent image carrier and a plurality of developing devices which contain toners of different colors from each other and perform a contacting / separating operation on the photoconductor. Are known. In this image forming apparatus, a superimposed toner image on a photoconductor formed by superimposing toner images of respective colors sequentially developed by the respective developing devices is collectively transferred to a transfer material, or each color on the photoconductor developed by each developing device is Are transferred onto the intermediate transfer body in a superimposed manner, and the superimposed toner image on the intermediate transfer body is collectively transferred to a transfer material, thereby forming a color image.

Further, as a developing device used in this type of image forming apparatus, a one-component developer composed of toner particles externally added with additives such as toner particles or auxiliary agents, that is, a developer containing no carrier particles is used. Is supplied to a developing roller as a developer carrying member, and a developing device of a one-component developing system in which a toner layer having a predetermined thickness is formed on the developing roller is known. This type of developing device does not need to control the toner concentration as compared with a two-component developing type developing device using a two-component developer composed of a toner and a carrier,
Further, since there is no need for mixing and stirring means for mixing and stirring the toner and the carrier, it is possible to simplify the maintenance and management of the apparatus and to obtain an advantage that the structure of the apparatus can be reduced.

[0004] Among the above-mentioned developing devices of the one-component developing system, those using a non-magnetic toner and those using a magnetic toner as a one-component developer are known. Regardless of which toner is used, a developer layer regulating member for forming a toner layer having a predetermined thickness on the developing roller is provided. In an apparatus using a non-magnetic toner, the toner is frictionally charged by the developer layer regulating member.

[0005] As the developer regulating member, a blade-shaped regulating blade is generally used. For example, when a so-called hard roller made of metal or resin is used as the developing roller, an elastic member such as urethane rubber is used as the regulating blade, and at least the surface of the developing roller has elasticity such as rubber. When a so-called soft roller having the following is used, a metal blade or the like is used as the regulating blade.

However, regardless of which regulating blade is used, the regulating blade is in contact with and pressed against the developing roller, so that the surface thereof wears over time, and it is difficult to extend the life of the regulating blade. . Also,
The toner staying at the contact portion between the developing roller and the regulating blade is melted by frictional heat generated between the blade and the rotating developing roller, and a toner mass is easily generated at the contact portion. In such a case, there is a problem that a streak-like mark is formed on the toner and white streaks are generated in the solid portion when the solid portion is developed. In particular, when a non-magnetic toner is used, the charging ability of the toner is degraded due to the wear of the regulating blade, the background of the non-image portion is stained due to insufficient charging of the toner, and the reproducibility of minute dots is reduced. There was a problem that would.

To solve such a problem, a developing device using a roller-shaped regulating roller as a developer regulating member instead of the regulating blade has been proposed. FIG. 2 is a configuration diagram illustrating an example of such a developing device. The illustrated developing device includes a developing container 10 having an opening facing the belt-shaped photoconductor 1, a developing roller 11, a toner supply roller 12 for supplying toner onto the developing roller 11, and a roller-shaped regulating roller. 14 and so on. Further, toner is stored in the toner in the developing container 10, and transport paddles 17 a, 17 b, and 17 are provided in each of the toner storage units to rotate the toner inside thereof to the toner supply roller 12 side.
17c is also provided.

In the developing device shown in FIG. 2, when the regulating roller 14 contacts and presses the developing roller 11 to which the toner is supplied by the toner supply roller 12, the same regulating force as when the regulating blade is used is exerted. Thus, a toner layer having a predetermined thickness is formed on the developing roller 11. In addition, by constantly rotating the regulating roller 14 during development in synchronization with the developing roller 11, the same portion of the surface of the regulating roller 14 is not always pressed against the developing roller. Therefore, the surface of the regulating roller 14 does not wear over time, and the toner does not stay at the contact portion between the developing roller 11 and the regulating roller 14.

[0009]

However, when a regulating roller is used as a developer layer regulating member, there are some problems as described below.

For example, in the developing device shown in FIG.
In order to synchronize with the rotation of the developing roller 11, the regulation roller 14 is set to be constantly rotated during development. However, in such a setting, there is a problem that the power consumption of the developing device is increased as compared with the developing device using the regulating blade.

In the developing device shown in FIG. 2, the regulating roller 14 is driven by a common driving motor as the developing roller 11. However, the regulating roller 14
In order to prevent the regulating force from becoming excessively large, it is necessary to set the rotating speed of the regulating roller 14 to be very small with respect to the rotating speed of the developing roller 11, and a large-scale deceleration mechanism is required. There has been a problem that the size and cost of the apparatus have been adversely affected. The developing roller 1
It is conceivable to drive each of the developing roller 1 and the regulating roller 14 with a dedicated drive motor. However, such a developing device requires at least two drive motors, which is also against the downsizing and cost reduction of the device. The problem arises.

Further, in the developing device shown in FIG.
The direction of rotation of the developing roller 11 and the regulating roller 14 is such that the surfaces of the two rollers move in opposite directions at the contact portion of the two rollers (hereinafter referred to as the counter direction).
Was set to. This is because if the rotation direction of both rollers is opposite to the counter direction, that is, if the surfaces of both rollers are set in the same direction at the contact portion, the toner regulated by the regulating roller 14 passes through the contact portion of both rollers. This is because the toner that has slipped out may leak out from the lower portion of the developing container 10 to cause contamination inside the image forming apparatus. However, if the rotation direction of both rollers is set in the counter direction as described above, a large driving torque is required to drive both rollers. For this reason, setting in the counter direction is a factor that further increases the power consumption of the developing device.

Further, when the driving torque of both rollers is increased, the rotation of the driving motor may be uneven, and the rotation speed of both rollers may fluctuate. Rotational unevenness of the drive motor can be avoided by using a high-performance drive motor having a sufficient margin for the required drive torque, but this is not preferable because it increases the cost and increases the size.
If the rotation speed of the developing roller increases, especially due to the rotation unevenness of the drive motor, the layer thickness of the toner formed on the developing roller changes, and the density unevenness on the image occurs. Was. It is considered that the problem of uneven rotation of the drive motor similarly occurs when the developing roller and the regulating roller are driven by a common drive motor and when they are driven by dedicated drive motors.

Here, in the configuration in which the developing roller and the regulating roller are rotated in the counter direction, the problem that the necessary driving torque is increased is disclosed in Japanese Patent Application Laid-Open No. Sho 60-1.
Japanese Patent Application Publication No. 03373 proposes a developing device in which the surface of a roller-shaped developer layer regulating member is plated with metal to reduce the friction coefficient of the surface and reduce the required driving torque. However, in the developing device described in this publication, since the friction coefficient of the surface of the developer layer regulating member is reduced, the charging ability of the toner when using a non-magnetic toner as the developer may be reduced,
As in the case where the regulating blade is used, problems such as the occurrence of background stain on the non-image portion due to the decrease in the toner charging ability and the decrease in reproducibility of minute dots remain.

The present invention has been made in view of the above problems, and a first object of the present invention is to reduce power consumption when a roller-shaped developer layer regulating member is used and to reduce the power consumption of a developer carrier. It is an object of the present invention to provide an image forming apparatus capable of suppressing the fluctuation of the rotation speed and preventing the occurrence of image density unevenness caused by the fluctuation.

It is a second object of the present invention to provide an image forming apparatus which achieves the above first object and which can reduce the size and cost of the apparatus.

[0017]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a developer supporting member; and a developer supporting member which is in contact with the developer supporting member and is supported by the developer supporting member. And a roller-shaped developer layer regulating member for regulating the layer thickness of the developer, which is separated from the latent image carrier at the time of non-development, and the developer carrier and the latent image carrier are fixed to a predetermined position prior to development. In an image forming apparatus including a developing device that performs a contacting / separating operation such as moving to a developing position that is in a positional relationship, the developer layer regulating member is moved in conjunction with the moving operation of the developing device performed prior to development. It is characterized in that control means for rotating is provided.

In this image forming apparatus, the roller-shaped developer layer regulating member is rotated in conjunction with a moving operation performed prior to the development of the developing device, and the regulating member is stopped during the development. deep. This rotation prevents the deterioration of the member surface over time and the retention of toner, which are likely to occur when the blade-shaped regulating member is used. In addition, during development, the roller-shaped developer layer regulating member comes into contact with the developer carrier in a stopped state, so that the same regulating force as when a blade-shaped regulating blade is used as the developer layer regulating member. Demonstrate. By rotating the roller-shaped developer layer regulating member only during the moving operation of the developing device performed prior to the development, compared to the case where the roller-shaped developer layer regulating member is constantly rotated during the development. Thus, power consumption is reduced. Further, during the development, the developer carrier and the developer layer regulating member are brought into contact with each other in a stopped state, so that the developer can be contacted while rotating in the counter direction during the development. The driving torque of the carrier is reduced, and fluctuations in the rotational speed of the developer carrier due to an increase in the driving torque are suppressed.

According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the control means is fixed to a rotating shaft of the developer layer regulating member, and An oscillating member having an axis as an oscillating center; and an oscillating member provided on the image forming apparatus main body and engaged with the oscillating member in conjunction with a movement operation of the developing device performed prior to development. And a guide member for guiding the swinging of the arm.

In this image forming apparatus, the swinging member and the guide member are engaged with each other in conjunction with the moving operation of the developing device performed prior to the development, so that the swinging member is connected to the developer layer. It swings around the rotation axis of the regulating member.
Then, the developer layer regulating member is rotated by a predetermined angle in accordance with the swing displacement of the swing member. Therefore, there is no need to provide a dedicated drive motor for rotating the developer layer regulating member, or to provide a deceleration mechanism or the like in the case of using a common drive motor with the developer carrier, for example. Thus, the developer layer regulating member can be automatically rotated by a predetermined angle.

According to a third aspect of the present invention, in the image forming apparatus of the second aspect, the oscillating member has a contact portion between the developer carrier and the developer layer regulating member, the surfaces of which are opposite to each other. And a one-way clutch for transmitting only the rotational driving force to the developer layer regulating member.

In this image forming apparatus, during the movement operation of the developing device performed prior to the development, the swing of the swing member is caused by the rotation driving force of the developer layer regulating member via the one-way clutch. Is transmitted to the rotating shaft of the developer layer regulating member. Thereby, the developer layer regulating member can be rotated by a predetermined angle in a direction (hereinafter, referred to as a counter direction) in which the surfaces of the developer layer regulating member move in directions opposite to each other at the contact portion with the developer carrier. Then, after the swing of the swing member is stopped and the rotation of the developer layer regulating member is stopped,
By the one-way clutch, the developer layer regulating member can stop the rotation in the direction opposite to the counter direction, that is, the direction in which the developer layer regulating member rotates together with the rotation of the developer carrying member. The stopped state of the member is maintained until the separation operation from the latent image carrier after the development is completed is started. Therefore, it is possible to prevent toner leakage from the developing device when the developer layer regulating member rotates in the co-rotating direction during development. Further, after the development is completed, the one-way clutch does not transmit the swing of the swing member in the direction opposite to the direction of the moving operation to the rotating shaft of the developer layer regulating member. While the stop state is maintained, only the swing member swings to return to the non-development state. As described above, by controlling the rotation direction of the developer regulating member in the counter direction by the one-way clutch, the developer layer regulating member can be intermittently rotated by a predetermined angle each time the swinging member swings. In addition, it is possible to reliably prevent the same portion on the surface of the developer layer regulating member from constantly contacting the developer carrier.

Here, in the developer carrier and the developer layer regulating member, the outer diameter changes due to environmental fluctuations such as humidity, regardless of the material used, and the gap between them changes due to the change. The contact pressure may change. Therefore, in order to absorb the change, it is conceivable to employ a configuration in which the developer layer regulating member is pressed against the developer carrier using a biasing means such as a spring. In the case of such a configuration, it is necessary to support the rotating shaft of the developer layer regulating member to a certain extent in a direction toward the developer carrier and a direction away from the developer carrier. For example, it is conceivable to provide a side plate of the developing device with a support hole larger than the outer diameter of the rotating shaft that allows the rotating shaft to move to some extent. However, if the developer layer regulating member is supported in a movable state as described above, the swing of the swing member may be changed depending on the position at which the swing member is guided by the guide member. When transmitting, the developer layer regulating member may generate a force to move in the direction away from the developer carrier. If the moving force is larger than the urging force of the urging means, the developer layer regulating member and the developer carrier are separated from each other, and as a result, the toner in the abutting portions of the two is scattered. There is a possibility that it will.

According to a fourth aspect of the present invention, in the image forming apparatus of the second or third aspect, a force is generated to move the guide member in a direction in which the developer layer regulating member approaches the developer carrier. The swing member is provided so as to be guided at a position where the swing member moves.

In this image forming apparatus, the swing member is guided by the guide member at a position where a force for moving the developer layer regulating member in a direction approaching the developer carrier is generated. When the swing of the moving member is transmitted as the rotational driving force of the developer layer regulating member, the developer layer regulating member and the developer carrier are prevented from being separated from each other. Therefore,
It is possible to prevent the toner from scattering at the contact portion between the developer layer regulating member and the developer carrier.

According to a fifth aspect of the present invention, there is provided an image forming apparatus according to the first aspect, wherein the control means includes a rotating means fixed to a rotating shaft of the developer layer regulating member. A gear, a connecting gear meshed with the rotating gear, and fixedly connected to the connecting gear and the image forming apparatus main body, and engaged with the connecting gear in conjunction with the movement of the developing device performed prior to development. And a guide member for guiding the connection gear to rotate.

In this image forming apparatus, the connecting gear rotates by the engagement of the connecting gear and the guide member in conjunction with the movement of the developing device performed prior to the development. When the rotating gear meshing with the connecting gear rotates around the rotation axis of the developer layer regulating member, the developer layer regulating member rotates by a predetermined angle according to the rotation angle of the rotating gear. Therefore, a dedicated drive motor for rotating the developer layer regulating member is provided,
For example, the developer layer regulating member can be automatically rotated by a predetermined angle in conjunction with the movement of the developing device without providing a deceleration mechanism or the like in the case of using a common drive motor with the developer carrier. . Further, by using a rotating gear and a connecting gear as the control means, the sliding friction with the guide member provided on the main body side can be reduced as compared with the case where the swinging member is used as the control means. In addition to reducing the driving torque required for the motor, noise at the time of engagement with the guide member can be prevented.

According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, the rotating gear has a contact portion between the developer carrier and the developer layer regulating member, the surfaces of which are opposite to each other. A one-way clutch for transmitting only the rotational driving force to move to the developer layer regulating member is provided.

In this image forming apparatus, when the developing device performs the movement operation during development, the rotation of the connecting gear is performed as the rotational driving force of the developer layer regulating member via the one-way clutch. The power is transmitted to a rotating gear fixed to the rotating shaft of the developer layer regulating member. Thereby, the developer layer regulating member can be rotated by a predetermined angle in the counter direction. Then, after the rotation of the connection gear stops and the rotation of the developer layer regulating member stops, the one-way clutch
The rotation of the developer layer regulating member in the direction along with the rotation of the developer carrier can be stopped, and the stopped state of the developer layer regulating member is moved away from the latent image carrier after the development is completed. Keep until the start. Therefore, it is possible to prevent toner leakage from the developing device when the developer layer regulating member rotates in the co-rotating direction during development. Further, after the development is completed, the one-way clutch does not transmit the rotation of the connecting gear and the rotating gear in the opposite direction to the direction of the moving operation to the rotating shaft, so that the stopped state of the developer layer regulating member is maintained. Only the connecting gear rotates to return to the non-development state. As described above, by controlling the rotation direction of the developer regulating member in the counter direction by the one-way clutch, the developer layer regulating member can be intermittently rotated by a predetermined angle at every rotation of the connection gear. The same portion on the surface of the developer layer regulating member can be prevented from constantly contacting the developer carrier.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color laser printer (hereinafter, referred to as "printer") as an image forming apparatus having four sets of developing devices will be described below.

FIG. 1 is a front view showing a schematic configuration of a printer according to the present embodiment. This printer includes a photosensitive belt 1 as a latent image carrier wound around a plurality of support rollers. The photoreceptor belt 1 is driven to rotate in a clockwise direction indicated by an arrow A in FIG.
Optical writing unit 4, four developing devices 5Bk, 5C,
5M and 5Y, an intermediate transfer belt 6 as an intermediate transfer body, a photoconductor cleaning device 7, and the like are arranged. An organic photosensitive layer is formed on the surface of the photosensitive belt 1.

When an image forming operation (printing operation) is performed by the printer, a high voltage is applied to the charger 3 so that the photosensitive belt 1 is uniformly charged. In an image signal processing unit (not shown), color image information, for example, a color image signal sent from an external computer is converted into an optical writing signal and sent to the optical writing unit 4. In the optical writing unit 4, a laser as a light source (not shown) is controlled based on the optical writing signal, and is transmitted via a polygon mirror 8, an f / θ lens 9 and a reflection mirror 10 to Black (Bk) and Cyan.
(C), optical writing corresponding to the image signals of Magenta (M) and Yellow (Y) is performed, and an electrostatic latent image is formed on the photosensitive belt 1.

The electrostatic latent image on the photoreceptor belt 1 is developed for each color by each of the developing devices 5Bk, 5C, 5M, and 5Y having toner of each color charged with a charge having a polarity opposite to that of the latent image. Is done. As a result, a toner image is formed on the photoreceptor belt 1 for each color.

At the contact portion between the photoreceptor belt 1 and the intermediate transfer belt 6, the toner image on the photoreceptor belt 1 is applied to the intermediate transfer belt 6 by applying a charge having a polarity opposite to that of the toner to the intermediate transfer belt 6. Is transferred to By repeating this toner image formation and transfer operation four times, a four-color superimposed color toner image is formed on the intermediate transfer belt 6.
The color toner image on the intermediate transfer belt 6 is transferred by a paper transfer roller 43 as a secondary transfer member onto transfer paper as a recording material sent from a paper feed cassette 40 or a manual feed tray 41 by a pair of conveying rollers 42. Is done. The transfer paper on which the color toner image has been transferred is fixed to a fixing roller pair 44.
And the toner image is fused and fixed.

Next, the developing device according to this embodiment will be described with reference to FIG. The developing device according to the present embodiment includes:
The developing device is a one-component developing system using a non-magnetic one-component toner (hereinafter, referred to as toner). Each developing device 5 has a developing container 1 having an opening facing the photosensitive belt 1.
0, a developing roller 11 as a developer carrier, a toner supply roller 12 for supplying toner onto the developing roller 11,
Toner storage sections 18a, 18b, 18c in developing container 10
Transport paddles 17a, 17b, 17c for sending out the toner stored in the supply roller 12 side, and a regulating roller 14 as a developer layer regulating member for forming a toner layer having a predetermined thickness on the developing roller 11. And so on.

The developing roller 11 is partly exposed from the opening of the developing container 10 so as to be rotatable in a counterclockwise direction indicated by an arrow at a predetermined linear velocity. The photosensitive drum 1 is transported to a developing position, which is a contact portion with the photosensitive drum 1, and develops a latent image formed on the photosensitive belt 1. In the present embodiment, a metal roller is used as the developing roller 12. The toner supply roller 12 includes the developing roller 11
, And is installed so as to be rotatable in the counterclockwise direction of the arrow, and the surface thereof is made of foamed polyurethane. Further, a toner regulating blade 13 is brought into contact with the toner supply roller 12 so that the amount of toner supplied to the developing roller 11 is regulated. Each transport paddle 17 is installed so as to be rotatable in a counterclockwise direction indicated by an arrow, and sends the toner to the supply roller 12 side by this rotation. As a material of each transport paddle, for example, a soft and elastic material such as polypropylene can be used. By utilizing the elasticity, the transport paddle rotates while being in close contact with the inner wall of the developing container 10 and reliably transports the toner.

The regulating roller 14 regulates the toner on the developing roller 11 to a predetermined layer thickness, and frictionally charges the toner by sliding on the toner.
The toner charged on the developing roller 11 develops the electrostatic latent image on the photosensitive belt 1. In the present embodiment, urethane rubber coated with resin is used as the material of the surface of the regulating roller 14. In addition, a regulating roller cleaning blade 16 is in contact with the regulating roller 14, and the surface of the regulating roller 14 that has passed through the contact portion with the developing roller 11 is cleaned.

In the present embodiment, the developing roller 11 and the regulating roller 1
In order to absorb a change in the outer diameter of the roller 4, a spring 19 is provided as urging means for the regulating roller 14, and the regulating roller 14 is pressed against the developing roller 11.

At the side end (left side in the figure) of each developing device 5,
The independently rotatable cams 50 are in contact with each other,
At the time of non-development, it is configured to perform a contact / separation operation such that the developing roller 11 moves away from the photosensitive belt 1 to a developing position where the developing roller 11 contacts the photosensitive belt 1 prior to development. When the electrostatic latent image on the photosensitive belt 1 is developed, for example, the electrostatic latent image of Bk is
When the cam 50Bk located at the rear of the developing device 5Bk is rotated by 180 degrees by a drive control unit (not shown), the developing device 5Bk is pushed out toward the photoreceptor belt 1, and the developing roller 11Bk is It moves to a developing position where it contacts the belt 1. Other color developing devices 5C, 5M, 5
When developing with Y, the corresponding cams 50C, 5C
0M and 50Y are driven to rotate.

Further, the printer of this embodiment is provided with a control means for rotating the regulating roller 14 in conjunction with the moving operation of each developing device 5 performed prior to the development.
FIG. 3 is a perspective view showing an example of the configuration of a printer including the control means. FIG. 4 is an explanatory diagram illustrating the state of the printer during non-development, and FIG. 5 is an explanatory diagram illustrating the state of the printer during development. In the example shown in the figure, the control means comprises a swing member 20 fixed to a rotating shaft 14a of the regulating roller 14, a swing center about the rotating shaft 14a, and a pin 21 fixed to a swing end, and an image forming apparatus. The oscillating member 20 is provided on a side plate (not shown) of the apparatus main body, and engages with the oscillating member 20 in conjunction with the moving operation of the developing device 5 performed prior to the development. And a guide member 22 that guides the vehicle. The swing member 20 applies only a rotational driving force to the regulating roller 14 such that the surfaces of both rollers move in opposite directions (hereinafter, referred to as a counter direction) at a contact portion between the developing roller 11 and the regulating roller 14. It has a one-way clutch for transmission.

In the above configuration, the moving operation of the developing device 5 performed prior to the development, that is, from the state of the developing device 5 during the non-development shown in FIG. 4 to the state of the developing device 5 during the development shown in FIG. The rocking member 20 and the guide member 22 are engaged with each other in conjunction with the moving operation to move the rocking member 20 around the rotating shaft 14a. More specifically, the guide member 2 having a configuration in which a pin 21 fixed to an end of the swing member 20 protrudes from a side plate on the main body device side.
The pin 21 is pushed down along the shape of the guide member 22 by moving to the right in the figure while contacting the contact member 2, and the swinging member 20 is rotated counterclockwise in the figure around the rotation shaft 14 a of the regulating roller 14. Rocks. Since the direction of the swing coincides with the direction in which the regulating roller 14 is rotated in the counter direction, the one-way clutch 23 transmits the swing of the swing member 20 to the rotating shaft 14a of the regulating roller 14, and the swing member 20
The regulating roller 14 automatically rotates by a predetermined angle in accordance with the swing displacement of. This rotation prevents deterioration of the member surface over time and accumulation of toner, which are likely to occur when a blade-shaped regulating member is used.

After the swing of the swing member 20 is stopped and the rotation of the regulating roller 14 is stopped, the regulating roller 14 is moved by the one-way clutch 23 in a direction opposite to the counter direction.
That is, the rotation of the regulating roller 14 in the direction that follows the rotation of the developing roller 11 is stopped, and the stopped state of the regulating roller 14 is maintained until the separation operation from the photosensitive belt 1 after the development is completed is started. . By preventing the rotation in the entrainment direction, toner leakage from the developing device 5 when the regulating roller 14 rotates in the entrainment direction during development is prevented, and toner contamination in the device is prevented. During development, the regulating roller 14 comes into contact with the developing roller 11 in a stopped state, and exerts the same regulating force as when a blade-like regulating blade is used as the developer layer regulating member.

When the development is completed, the developing device 5 moves to the left again in the drawing, and the developing roller 11 is separated from the photosensitive belt 1. That is, the developing device 5 shifts from the state shown in FIG. 5 to the state shown in FIG. A return spring (not shown) connected to the rotation shaft 14 a of the regulating roller 14 is provided at the swing end of the swing member 20, and the pin 21 guides the pin 21 with the separating operation of the developing device 5 by the return spring. 22 while moving it to the left in the figure. By this movement, the swing member 20 swings clockwise in FIG. 4 and returns to the position shown in FIG. During the separating operation of the developing device 5, the one-way clutch 23 causes the swing member 2 to move.
0 is not transmitted to the rotating shaft 14a of the regulating roller 14, so that the regulating roller 1
While the stop state of No. 4 is maintained, only the swing member 20 swings and returns to the non-development state.

As described above, according to the present embodiment, the regulating roller 14 is rotated by a predetermined angle only during the moving operation of the developing device 5 performed prior to the development, as compared with the case where the regulating roller 14 is constantly rotated during the development. Power consumption can be reduced. During development, the developing roller 11 and the regulating roller 1
4, the driving torque of the developing roller 11 is reduced as compared with the case where both rollers come into contact with each other while rotating in the counter direction during the development,
The fluctuation of the rotation speed of the developing roller 11 due to the increase of the driving torque can be suppressed. As a result, it is possible to prevent image density unevenness from occurring due to the fluctuation.
Further, since the regulating roller 14 is automatically rotated by a predetermined angle in conjunction with the moving operation of the developing device 5 performed prior to the development, a dedicated driving source for rotating the regulating roller 14 is provided. There is no need to provide a deceleration mechanism or the like when using a common drive source. This makes it possible to reduce the size and cost of the device. Further, the one-way clutch 23 controls the regulating roller 1.
By controlling the rotation direction of the rotation member 4 in the counter direction, the regulation roller 14 can be intermittently rotated by a predetermined angle every time the swing member 20 swings.
The same portion of the surface can be prevented from constantly contacting the developing roller 11. As a result, the wear of the surface of the regulating roller 14 with time can be prevented, the service life of the regulating roller 14 can be extended, and the deterioration of the charging ability of the toner due to the abrasion can be prevented. This can prevent the occurrence of background stain on the non-image portion and a decrease in the reproducibility of minute dots due to the above.

[Modification 1] Next, a modification of the embodiment of the present invention will be described. In the configuration shown in FIGS. 3 to 5, the regulating roller 14 is rotatably supported by the side plate 50 of the developing device 5 via the bearing 15. As shown in FIG. 6, the bearing 15 is engaged with a long oblique hole 50a formed in the side plate 50, and is directed toward the developing roller 11 by the urging force of the spring 19.
It is configured to be able to move by a predetermined distance in a diagonally upper right direction and in a diagonally lower left direction in FIG. 3 opposite to the urging force. Also,
The starting end of the spring 19 is mounted in the elongated hole 50a. In such a configuration, depending on the position at which the swing member 20 is guided by the guide member 22, when the swing of the swing member 20 is transmitted as the rotational driving force of the regulation roller 14, the regulation roller 14
There is a possibility that a force for moving in a direction away from the camera may be generated. If the moving force is greater than the urging force of the spring 19, the regulating roller 14 and the developing roller 1
1 are separated from each other, and as a result, the toner at the contact portion between the two rollers may be scattered.

Therefore, in the present modification, the guide member 22 is moved at such a position that the force for moving the regulating roller 14 in the direction away from the developing roller 11 is not generated.
0 is guided. FIG. 7 shows an example of such a configuration. Since the component F1 of the normal force F of the guide member 22 in the direction of the rotation axis 14a of the regulating roller 14 is given to the rotation axis 14a, the rotation axis 14a has a component F2 in the direction orthogonal to the direction between the two roller centers of F1. Occurs. By this F2, the swing member 20 is pushed up by the guide member 22 in conjunction with the movement operation during the development of the developing device 5, so that the swing of the swing member 20 is transmitted as the rotational driving force of the regulating roller 14. In addition, it is possible to prevent the regulation roller 14 and the developing roller 11 from being separated from each other, and to prevent toner scattering at a contact portion between the two rollers. Actually, a force for moving the regulating roller shaft is generated due to the frictional force at the contact point between the two rollers. Therefore, the position at which the swing member 20 is guided by the guide member 22 is set such that the force obtained by combining the component F2 with the component of the force in the direction between the roller centers causes the regulating roller 14 to face the developing roller 11. I do.

[Modification 2] Next, Modification 2 of the embodiment of the present invention will be described. FIG. 8 is a schematic configuration diagram of a printer according to the second modification. FIG. 8 shows a non-developing state in which the developing roller 11 is separated from the photosensitive belt 1. In this printer, the control means includes a rotating gear 60 fixed to the rotating shaft 14a of the regulating roller 14 and a connecting gear 64 fixed to the pin 61 and meshing with the rotating gear 60.
The connecting gear 64 is provided in the image forming apparatus main body, and interlocks with the moving operation of the developing device 5 performed prior to the development.
And a guide member 62 for guiding the connection gear 64 to rotate by contact with the guide gear 62. The rotary gear 60 is press-fitted with a one-way clutch that transmits only a rotational driving force to the regulating roller 14 to rotate the regulating roller 14 in the counter direction.

In the above configuration, the coupling gear 64 and the guide member 62 are engaged with each other in conjunction with the movement of the developing device 5 performed prior to the development, whereby the coupling gear 64 is engaged.
Rotates. More specifically, the pin 61 fixed to the connection gear 64 moves rightward in the drawing while contacting the guide member 62 having a configuration protruding from the side plate on the main body device side, so that the connection gear 64 is moved in the drawing. Rotate clockwise. And
The rotating gear 60 meshing with the connecting gear 64 is
Rotate counterclockwise around the rotation axis 14a of FIG. Since the direction of this rotation coincides with the direction in which the regulating roller 14 is rotated in the counter direction, the one-way clutch 63 causes the rotation of the rotating gear 60 to rotate on the rotating shaft 1 of the regulating roller 14.
4a, and the regulating roller 14 automatically rotates by a predetermined angle according to the rotation angle of the rotating gear 60.

After the rotation of the rotating gear 60 is stopped and the rotation of the regulating roller 14 is stopped, the regulating roller 14 is moved by the one-way clutch 63 in a direction opposite to the counter direction.
That is, the rotation of the regulating roller 14 in the direction that follows the rotation of the developing roller 11 is stopped, and the stopped state of the regulating roller 14 is maintained until the separation operation from the photosensitive belt 1 after the development is completed is started. . During development, the regulating roller 14 comes into contact with the developing roller 11 in a stopped state, and exerts the same regulating force as when a blade-shaped regulating blade is used as the developer layer regulating member. After the development is completed, the developing device 5 returns to the position shown in FIG. During the separating operation of the developing device 5, the one-way clutch 63 causes the connecting gear 64 and the rotating gear 60 to rotate.
The rotation in the direction opposite to the above-described movement operation is performed by the rotation shaft 14a.
The rotation gear 60 and the coupling gear 64 rotate to return to the non-development state while the regulating roller 14 is kept stopped.

According to this modification, the control means is constituted by using the rotary gear 60 and the connecting gear 64, so that the control means is provided on the main body side as compared with the case where the control means is constituted by using the swing member. Since the sliding friction with the guide member can be reduced, the driving torque required for the moving operation of the developing device 5 can be reduced, and noise at the time of engagement with the guide member 62 can be reduced.

[0051]

According to the first to sixth aspects of the present invention, the power consumption when the roller-shaped developer layer regulating member is used is suppressed, and the fluctuation of the rotation speed of the developer carrier is suppressed. There is an effect that it is possible to prevent the resulting image density unevenness. Further, while exerting the same regulating force as when a blade-shaped regulating blade is used as a developer layer regulating member, it is possible to prevent the deterioration of the regulating member surface, which tends to occur when using the regulating blade, with time and the accumulation of toner. Can be. As a result, it is possible to extend the life of the developer layer regulating member, and to form a good image without white stripes due to background contamination due to the aging and toner retention. is there.

In particular, according to the second and fifth aspects of the present invention, in conjunction with the moving operation of the developing device performed prior to the development,
The developer layer regulating member can be automatically rotated by a predetermined angle. Accordingly, there is no need to provide a dedicated drive motor for rotating the developer layer regulating member, or to provide a large-scale deceleration mechanism or the like when using a common drive motor with the developer carrier, for example. There is an effect that cost reduction and cost reduction can be achieved.

In particular, according to the third and sixth aspects of the present invention, the developer layer regulating member is prevented from rotating in the co-rotational direction with respect to the rotation of the developer carrying member during the development, so that the developing device is prevented from rotating. This has the effect of preventing toner leakage, thereby preventing toner contamination in the image forming apparatus.

In particular, according to the invention of claim 4, it is possible to prevent the developer layer regulating member and the developer carrier from separating from each other,
There is an effect that scattering of the toner at the contact portion between the two can be prevented.

In particular, according to the fifth aspect of the present invention, by using a rotating gear and a connecting gear as the control means, the driving torque required for the moving operation of the developing device can be reduced and the engagement with the guide member can be reduced. There is an effect that noise at the time can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a schematic configuration of a printer according to an embodiment.

FIG. 2 is a schematic configuration diagram of a developing device in the embodiment.

FIG. 3 is a perspective view of a printer including a control unit according to the embodiment.

FIG. 4 is an explanatory diagram illustrating a state of the printer during non-development in the embodiment.

FIG. 5 is an explanatory diagram illustrating a state of the printer during development in the embodiment.

FIG. 6 is an explanatory diagram for explaining a long hole formed in a side plate of the developing device in the embodiment.

FIG. 7 is a schematic configuration diagram of a printer according to a modification of the embodiment.

FIG. 8 is a schematic configuration diagram of a printer according to another modification of the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoreceptor belt 3 charger 4 optical writing unit 5 developing device 6 intermediate transfer belt 7 photoreceptor cleaning device 10 developing container 11 developing roller 12 toner supply roller 13 toner regulating blade 14 regulating roller 14a rotating shaft 15 bearing 16 regulating roller cleaning blade 17 Conveyance Paddle 18 Toner Storage 19 Spring 20 Swinging Member 21 Pin 22 Guide Member 23 One-Way Clutch 40 Paper Cassette 41 Manual Tray 42 Conveyor Roller Pair 43 Paper Transfer Roller 44 Fixing Roller 50 Cam 60 Rotating Gear 61 Pin 62 Guide Member 63 One-way clutch 64 Connecting gear

Claims (6)

[Claims] An image forming apparatus comprising: a developer carrier; and a roller-shaped developer layer regulating member that contacts the developer carrier and regulates a layer thickness of the developer carried on the developer carrier. A developing device that separates from the latent image carrier during non-development and performs a contact / separation operation such that the developer carrier moves to a developing position where the developer carrier has a predetermined positional relationship with the latent image carrier prior to development; The image forming apparatus according to claim 1, further comprising control means for rotating the developer layer regulating member in conjunction with the movement of the developing device performed prior to development. 2. The image forming apparatus according to claim 1, wherein said control means is fixed to a rotating shaft of said developer layer regulating member, said swinging member having said rotating shaft as a swing center, and an image forming apparatus main body. And a guide member that guides the swinging member to swing by engaging with the swinging member in conjunction with the moving operation of the developing device performed prior to development. An image forming apparatus comprising: 3. An image forming apparatus according to claim 2, wherein said oscillating member is configured such that surfaces of said oscillating member move in opposite directions at a contact portion between said developer carrier and said developer layer regulating member. An image forming apparatus comprising a one-way clutch for transmitting only a rotational driving force to a developer layer regulating member. 4. The image forming apparatus according to claim 2, wherein the guide member is swung at a position where a force for moving the developer layer regulating member in a direction away from the developer carrier is not generated. An image forming apparatus provided to guide members. 5. The image forming apparatus according to claim 1, wherein the control means is fixed to a rotating gear fixed to a rotating shaft of the developer layer regulating member and a connecting gear meshed with the rotating gear. A gear, a guide member provided on the image forming apparatus main body, and interlocking with the moving operation of the developing device performed prior to the development, engaging with the connecting gear to guide the connecting gear to rotate. An image forming apparatus characterized by comprising: 6. The image forming apparatus according to claim 5, wherein the rotating gear rotates at a contact portion between the developer carrier and the developer layer regulating member such that both surfaces move in opposite directions. An image forming apparatus comprising a one-way clutch for transmitting only a driving force to a developer layer regulating member.