JP2003084572A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize toner sticking amount and toner charged amount on a developer carrier and to prevent the deterioration of image quality by preventing retaining of toner on the developer carrier and preventing the sticking thereof with the lapse of time in an image forming apparatus. SOLUTION: This image forming apparatus is equipped with a developing device for developing an electrostatic latent image on an image carrier by supplying developer to the developer carrier 48 by a developer supply member 51 and sticking the developer by the developer carrier. Then, a driving controller 60 is provided as a developer supply member controller and the developer supply member is driven to reversely rotate or stop so as to make the relative speed of the developer supply member to the developer carrier higher at the time of non-developing, and a position controller is provided and the developer supply member is made to approach to the developer carrier so as to make the frictional force of the developer supply member to the developer carrier larger than that at the time of developing.

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 printer, a facsimile, or a complex machine thereof, and in particular, repeatedly charging, writing, developing, transferring, cleaning and the like on an image carrier. The present invention relates to an electrophotographic image forming apparatus that sequentially forms toner images and sequentially transfers the toner images to form an image on a transfer material such as a sheet or an intermediate transfer body. More specifically, the present invention relates to an image forming apparatus including a developing device that develops an electrostatic latent image on an image carrier by adhering a developer supplied by a developer supply member with a developer carrier.

[0002]

2. Description of the Related Art Conventionally, in a developing device of an image forming apparatus of this type, there is a case where a one-component developer consisting of toner alone is used as a developer and a case where a two-component developer consisting of toner and a carrier is used. there were. When a one-component developer is used, there are a non-magnetic toner and a magnetic toner.

However, when a two-component developer is used,
It is disadvantageous in terms of downsizing, cost reduction, reliability, etc. as compared with the case of using a one-component developer, such as requiring a carrier and a toner concentration sensor. Further, in the case of color, since the magnetite and the like are dispersed in the resin in the magnetic toner, it becomes a dull color with low saturation, and it is advantageous to use the non-magnetic toner in terms of transparency. Therefore, it has been preferable to use a non-magnetic one-component developer in this type of developing device.

In a developing device using a non-magnetic one-component developer, conventionally, a developer carrying member such as a developing roller, which carries a toner as a one-component developer on its surface and adheres to the image carrying member,
A developer storage unit such as a toner hopper that stores toner, a developer transport member such as an agitator that transports the toner stored therein, and a developer carrier are provided in contact with the developer transport member. It is provided with a developer supply member such as a toner supply roller for supplying to the developer carrier, and a developer thinning member such as a doctor blade for thinning the toner thereon.

By the way, the developer carrier having no unevenness on the surface cannot sufficiently carry the toner required for development. Therefore, conventionally, as the developer carrying member, for example, a so-called blast roller in which beads or sand (sand) is sprayed on the surface at a constant pressure to form a large number of irregularities and the surface roughness Rz is about 10 to 20 is used. I often use it. As the developer supply member, for example, a member made of sponge, which rotates in a direction of compressing the developer with the developer carrying member, is often used.

[0006]

However, in the above-described conventional developing device, the toner on the developer carrying member may remain on the developer carrying member without being used for development. At this time, the toner remains. In some cases, new toner supplied from the developer supplying member rides on the toner, and the toner in the lower layer enters the surface concave portion and is constrained to become immobile.

While this is repeated, the proportion of the toner that does not contribute to the development among the toners carried by the developer carrier gradually increases, and the toner is repeatedly rubbed by the doctor blade which is a developer thinning member. Eventually, it becomes fine powder and softens, and it stays on the developer carrying member, which progresses and finally sticks.

When the amount of toner staying and adhering on the developer carrier increases, the developer carrier loses its function, and the toner adhesion amount and toner charge amount necessary for development cannot be obtained. However, there is a problem in that, due to uneven toner adhesion, for example, a blank image is generated and the image quality is deteriorated.

Therefore, among the conventional developing devices, for example, as disclosed in Japanese Patent Laid-Open No. 7-160108,
The width of the pressure contact portion between the developer carrier and the developer supply member is a, the peripheral speed of the developer carrier is V1, the peripheral speed of the developer supply member is V2, the number of cells of the developer supply member is n, and the developer is When the hardness of the supply member is ρ, 400 ≦ a × (n / 25) × {(V1 + V2) / V
There is one that tries to solve the above problem by satisfying the relationship of 1} × ρ ≦ 1000. However, even with the passage of time, it has not been possible to prevent the toner from staying on the developer carrier and prevent the toner from sticking.

Therefore, the first object of the present invention is to prevent the toner on the developer carrying member from staying and to prevent the toner from sticking to the toner on the developer carrying member in the image forming apparatus even with the passage of time. The purpose is to stabilize the amount of adhesion and the amount of toner charge and prevent deterioration of image quality.

A second object of the present invention is to achieve the first object with a simple structure by drivingly controlling the developer supply member.

A third object of the present invention is to change the moving direction of the developer supplying member with respect to the developer carrying member,
It is to achieve the first object with a simple configuration.

A fourth object of the present invention is to change the movement of the developer supply member with respect to the developer carrying member to achieve the first object.
To achieve the purpose of.

A fifth object of the present invention is to achieve the first object by controlling the position of the developer supply member with respect to the developer carrying member.

A sixth object of the present invention is to achieve the first object in balance with prevention of deterioration of the developer carrying member.

[0016]

Therefore, in order to achieve the above-mentioned first object, the invention according to claim 1 supplies a developer to a developer carrying member by a developer supplying member, and carries the developer carrying member. In an image forming apparatus equipped with a developing device that develops an electrostatic latent image on an image bearing member by adhering the developer on the image bearing member, the frictional force of the developer supplying member against the developer bearing member during development is less than that during development. It is characterized by comprising an increasing developer supply member control device.

According to a second aspect of the present invention, in order to achieve the above-mentioned second object, in the image forming apparatus according to the first aspect, as a developer supply member control device, development for a developer carrier is performed during non-development. A drive control device for increasing the relative speed of the agent supply member is provided.

According to a third aspect of the present invention, in order to achieve the third object described above, in the image forming apparatus according to the second aspect, the drive control device causes the driving direction of the developer supply member to move relative to the developer carrying member. Is switched from the forward direction to the reverse direction to increase the relative speed.

According to a fourth aspect of the present invention, in order to achieve the above-mentioned fourth object, in the image forming apparatus according to the second aspect, the drive control device supplies the developer with respect to the movement of the developer carrier. It is characterized in that the movement of the member is stopped and the relative speed is increased.

According to a fifth aspect of the invention, in order to achieve the fifth object described above, in the image forming apparatus according to the first aspect, the developer supply member control device serves as a developer supply member control unit for a developer carrier. And a position control device for bringing the developer supply member closer to the developer supply member.

According to a sixth aspect of the invention, in order to achieve the sixth object described above, in the image forming apparatus according to any one of the first to fifth aspects, the developer supply member control device is driven periodically. The feature is that

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall schematic structure of an internal mechanism in a black-red two-color copying machine according to the present invention.

Reference numeral 10 in the figure denotes a copying machine main body.
A drum-shaped image carrier (photoconductor) 11 is provided in the main body 10 of the copying machine, and a first charging device 12, a black first developing device 13, a second charging device 37, and a second writing device are provided around the image carrier. 38, red second developing device 39, transfer / conveyance device 14,
The cleaning device 15 and the like are arranged.

A first writing device 16 is provided above them. The first writing device 16 includes a light source 40 such as a laser diode, a rotary polygon mirror 41 for scanning which is a polygon mirror, a polygon motor 42, an fθ lens 43 and a mirror 4.
4 and the like are provided with a scanning optical system and the like. The fθ lens 43 and the mirror 44 are made of plastic.

A fixing device 17 is provided on the left side of the cleaning device 15 in the figure. The fixing device 17 is provided with a fixing roller 18 having a built-in heater and a pressure roller 19 that presses the fixing roller 18 from below.

A document reading device 20 is provided in the upper part of the apparatus main body 10. The document reading device 20 includes a light source a,
A plurality of mirrors b, an imaging lens c, an image sensor d such as a CCD, and the like are provided.

On the other hand, in the lower part of the apparatus main body 10, a double-sided unit 22 and a paper feed cassette 23 are provided in two upper and lower stages. From the duplex unit 22 and the paper feed cassette 23,
A paper discharge path communicating with a paper feed path 24 extending below the image carrier 11 is provided. To the double-sided unit 22, a reversing path 26 is formed by branching from the middle of the paper discharge path 25 extending from the outlet of the fixing device 17.

A contact glass 27 is set on the upper surface of the apparatus body 10. The contact glass 2
An automatic document feeder 28 is openably and closably mounted on the apparatus body 10 so as to cover 7.

By the way, a manual feed tray 29 for guiding the manual feed sheet (transfer material) to the paper feed path 24 is provided on the right side surface of the apparatus main body 10 so as to be openable and closable. On the other hand, on the left side surface of the apparatus main body 10, a sorter 30 for receiving sheets discharged through the paper discharge path 25 is attached. Then, the apparatus main body 10 is placed on the paper feed table 31. In the paper feed table 31, the paper feed cassettes 23 are provided in multiple stages.

In the meantime, when making a copy using this laser copying machine, the manuscript is set in the automatic manuscript feeder 28, or the manuscript feeder 28 is opened and the manuscript is set directly on the contact glass 27. To do. Then, by pressing a start switch (not shown) and driving the automatic document feeder 28, the original conveyed on the contact glass 27 or the original set on the contact glass 27 is set. The document reading device 20
Read by color and convert to black and red electrical digital image signal.

At the same time, the appropriate paper feed roller 33 is rotated,
Corresponding paper feed cassettes 23 among the plurality of paper feed cassettes 23 provided in the apparatus main body 10 and the paper feed table 31 in multiple stages
Sheets such as paper and OHP film are fed out from inside,
The sheet is put in the sheet feeding path 24, conveyed by the conveying roller 34, and abutted against the registration roller 35 to be stopped. The image carrier 11
The registration roller 35 is rotated in synchronism with the rotation of, and is fed below the image carrier 11.

Alternatively, the paper feed roller 3 in the manual paper feed section
6 is rotated and the manual sheet set on the open manual tray 29 is put into the paper feed path 24, and similarly, the registration roller 35 moves the image carrier 11 below the image carrier 11 at the same timing as the rotation of the image carrier 11. Send in.

On the other hand, when a start switch (not shown) is pressed, the image carrier 11 is simultaneously rotated clockwise in the figure.
Then, as the image carrier 11 rotates, the surface of the image carrier 11 is first uniformly charged by the first charging device 12, and then the laser beam is generated based on the black digital image signal according to the read content read by the document reading device 20 described above. By irradiating L, black writing is performed by the first writing device 16, an electrostatic latent image is formed on the surface of the image carrier 11, and then black toner is attached by the first developing device 13 and the electrostatic latent image is formed. Visualize the latent image.

Subsequently, the second charging device 37 uniformly charges the laser light, and the second writing device 38 laser-processes the red document image signal according to the read content read by the document reading device 20. Red writing is performed by irradiating light to form an electrostatic latent image corresponding to the red component of the color original document on the black toner image, and then the second developing device 39 attaches the red toner. The electrostatic latent image is visualized. As a result, a two-color image including a black toner image and a red toner image is formed on the image carrier 11.

Then, the two-color image is transferred by the transfer / conveying device 14 to the sheet fed below the image carrier 11 as described above. The image carrier 11 after the image transfer is
The cleaning device 15 removes the residual toner and cleans the surface to prepare for the next similar image formation.

On the other hand, the sheet after the image transfer is conveyed by the transfer / conveyance device 14 and placed in the fixing device 17, and the fixing roller 1
8 and the pressure roller 19 apply heat and pressure to fix the transferred image. Then, the sheets are sorted into the sorter 30 through the sheet discharge path 25 and discharged.

When recording images on both sides of the sheet,
The paper is fed from the paper discharge path 25 to the reversing path 26, reversed by the duplex unit 22 and then put back into the paper feeding path 24, and after the image on the image carrier 11 is transferred onto the back surface of the sheet by the transfer / conveyance device 14,
The transferred image is fixed by the fixing device 17 and discharged to the sorter 30.

FIG. 2 shows an overall schematic structure of the second developing device 39 used in the above-mentioned two-color copying machine.

In the illustrated two-color copying machine, the image carrier 11 is rotated in the direction of the arrow (clockwise in the figure) at, for example, 200 mm / sec.

The second developing device 39 is provided with a casing 47 having an opening 46 toward the image carrier 11. Then, in the casing 47, a developer carrier 48 that carries toner on the surface and adheres to the image carrier 11, a developer storage unit 49 that stores the toner, and a developer that conveys the toner stored therein. Conveying member 50 and developer carrier 48
A developer supply member 51 for supplying the toner carried by the developer carrying member 50 to the developer carrying member 48.
And a developer thinning member 52 for thinning the toner thereon.

The developer carrying member 48 is a so-called developing roller, which is an Al core metal roller having a diameter of 20 mm and is 1.5 kg / cm.
The air pressure is set to ² and the bead blast particles (# 60) are sprayed to set the surface roughness Rz to about 11.5. Then, a part of the casing 47 is exposed through the opening 46 and faces the image carrier 11 with a predetermined gap, and at the facing portion, the image carrier 11 rotates in the forward direction at substantially the same peripheral speed. To do. In other words, in this example, it rotates counterclockwise in the figure at about 220 mm / sec in a non-contact manner with the image carrier 11, and the peripheral speed ratio of the image carrier 11 and the developer carrier 48 is set to 1: 1.1. To do.

The developer storage means 49 is a so-called toner hopper and stores non-magnetic toner which is a one-component developer. The developer carrying member 50 is a so-called agitator, and carries the toner stored in the developer storing means 49 to the developer supplying member 51 while stirring.

The developer supplying member 51 is a toner supplying roller and has a resistivity of about 1 × around a core metal roller 53 having a diameter of 6 mm.
It is a sponge roller provided with a conductive sponge layer 54 of 10 ⁶ Ωcm. As the sponge layer 54, carbon 10
A foamed polyurethane is used in which wt% is internally added and dispersed, and then foamed and molded. This developer supply member 51
The surface pore diameter is 0.2 to 0.3 mm on average.

Then, the developer carrying member 48 is supported by being pressed into the developer carrying member 48 by a predetermined amount, and is rotated in the forward direction with respect to the developer carrying member 48, that is, in the clockwise direction in the drawing. The peripheral speed is set to 1.3 times that of the developer carrying member 48, and by rubbing the toner, it is negatively charged in the illustrated example.

The developer thinning member 52 is, for example, a doctor blade, made of polyurethane rubber having a plate thickness of 2 mm in a blade shape, and its tip is brought into contact with the developer carrying member 48 at a light contact pressure of 10 to 20 g / cm. Contact. Then, the developer carrier 4
By the rotation of 8, the toner layer on the developer carrying member 48 is rubbed and made uniform. As a result, a toner layer having a toner adhesion amount of 1.2 to 1.8 mg / cm ² and an average charge amount of 8 to 20 μC / g is formed on the developer carrying member 48.

That is, in the second developing device 39 shown in FIG. 2, the toner stored in the developer storing means 49 is conveyed while being stirred by the developer conveying member 50, and the developer supplying member 5 is supplied.
1 supplies to the developer carrying member 48. The toner on the developer carrying member 48 is regulated to a certain amount by the developer thinning member 52, and is transferred to the image carrying member 11 when passing through the portion facing the image carrying member 11, and the image carrying member is carried. The electrostatic latent image on the body 11 is visualized to form a red toner image.

After that, the toner remaining on the developer carrying member 48 without being transferred to the image carrying member 11 is mechanically scraped off by the developer supplying member 51 to be removed from the developer carrying member 48.
Further, the developer supply member frictionally charges the charge on the developer carrier 48 to make it constant, thereby initializing the surface of the developer carrier 48.

Now, in FIG. 3, the second developing device 3 described above is used.
9 shows a drive transmission system for the developer carrier 48 and the developer supply member 51 of No. 9. FIG. 4 is an electric block diagram of a drive transmission system for the developer supply member 51.

As shown in FIG. 3, the center shaft 56 of the developer carrying member 48 has both ends rotatably supported by both side plates of the casing 47, and a drive gear 57 is attached to a portion protruding from one of the side plates. . The developer carrier 48 rotates by transmitting rotation to the drive gear 57 from a motor (not shown) provided in the apparatus body 10.

Further, the core metal roller 5 of the developer supply member 51
3 also has both ends rotatably supported by both side plates of the casing 47. Then, a developer supply member drive motor 61 of a drive control device (developer supply member control device) 60 is coupled to a portion protruding from one of the side plates via a coupling 58.
Attach. This motor 61 is capable of forward and reverse rotation and has a brake.

As shown in FIG. 4, the drive controller 60 is connected to the controller 62. The controller 62 is a CPU
A main control unit 63 including a memory and an I / O unit 64. A development drive time counter 65 is connected to the main control unit 63 via the I / O unit 64.

Then, the developing drive time counter 65 counts the developing drive time of the developing device 39, and the main controller 63 of the controller 62 controls the I / O every time, for example, one hour is exceeded.
A control signal is sent to the drive control device 60 via the section 64 to reversely drive the motor 61 of the drive control device 60 to switch the rotation direction of the developer supply member 51 with respect to the developer carrier 48 from the forward direction to the reverse direction. This reversal drive is performed for 10 to 20 seconds at a peripheral speed of 0.5 to 1 times the peripheral speed of the developer carrying member 48. At this time, the developer carrying member 48 rotates counterclockwise as in the case of development.

As a result, at the time of non-development, the developer carrier 4
8, the relative speed of the developer supply member 51 is increased to increase the frictional force, and the toner staying or fixed on the developer carrier 48 is scraped off by the developer supply member 51, and the surface of the developer carrier 48 is scraped off. Is always kept in the initial state, toner retention and sticking are prevented even over time, and the toner adhesion amount and toner charge amount on the developer carrying member 48 are stabilized, and after tens of thousands of images are formed. Can prevent the deterioration of image quality.

The time interval for the reversal drive is determined by the diameter of the developer carrier 48 and the developer supply member 51, the developer carrier 48, and the like.
It depends on the bite amount of the developer supply member 51, the peripheral speed of the developer supply member 51, the type of toner, and the like.

By the way, in the above-described example, the drive control device 60 switches the rotation direction of the developer supply member 51 from the forward direction to the reverse direction while rotating the developer carrying member 48 in the same manner as during development. However, while rotating the developer carrier 48 in the same manner as during development, the rotation of the developer supply member 51 is reduced to 30
The relative speed may be increased by stopping for 40 seconds. Even in this case, the same effect as described above can be obtained.

FIG. 5 shows a position control device for the developer supply member 51, which is another example of increasing the relative speed of the developer supply member 51 with respect to the developer carrier 48. FIG. 6 shows an electric block diagram thereof.

In this example, as shown in FIG. 5, a torsion spring 71 and an eccentric cam 72 of a position control device (developer supply member control device) 70 are arranged with a core metal roller 53 of the developer supply member 51 interposed therebetween. The torsion spring 71 urges the developer supply member 51 in the arrow direction, that is, in the direction away from the developer carrier 48. On the other hand, the eccentric cam 72 that decenters the eccentric amount e has a stepping motor 73 of the position controller 70.
Transmits the rotation of. As shown in FIG. 6, the control device 62 is connected to the position control device 70.

Then, the developing drive time counter 65 counts the developing drive time of the developing device 39, and every time, for example, one hour is exceeded, the main controller 63 of the controller 62 controls the I / O.
A control signal is sent to the position control device 70 via the portion 64, the stepping motor 73 of the position control device 70 is driven to rotate the eccentric cam 72, and the cored bar roller 73 is pushed against the torsion spring 71. The developer supply member 51 is brought close to the carrier 48, and the bite amount is increased for 10 to 20 seconds so that it becomes 1.5 to 2 mm.

At this time, the developer carrier 48 and the developer supply member 51 rotate in the forward direction as in the case of development.

In this way as well, the developer carrier 4 is similarly obtained.
8 increases the frictional force of the developer supply member 51 with respect to 8, and scrapes off the toner staying or fixed on the developer carrier 48 by the developer supply member 51 at the time of non-development so that the surface of the developer carrier 48 is always initialized. In this state, the retention of toner is prevented and the toner is prevented from sticking over time to stabilize the toner adhesion amount and toner charge amount on the developer carrying member 48, and image quality is maintained even after tens of thousands of images are formed. Can be prevented.

Now, in the above-mentioned example, the drive controller 60
And a developer supply member control device such as a position control device 70,
Periodically (every hour) based on the drive time of the developing device 39
Driven to. However, the developer carrier 48 may be cleaned each time the job is completed after the main power switch of the apparatus main body 10 is turned on, not limited to every fixed time.

However, in this case, if the frequency of cleaning increases, the sponge layer 54 of the developer supplying member 51.
It will accelerate the deterioration of the environment. Therefore, it is preferable to perform cleaning in consideration of prevention of deterioration of the developer supply member 51, instead of cleaning indiscriminately.

[0063]

As described above, according to the first aspect of the invention, the frictional force of the developer supply member against the developer carrying member is increased by the developer supply member control device during non-development compared with during development. From the above, by the function of this developer supply member control device, the toner staying or fixed on the developer carrier is scraped off by the developer supply member, and the surface of the developer carrier is always kept in the initial state, and even over time. It is possible to prevent the toner from staying and to prevent the toner from sticking to stabilize the toner adhesion amount and the toner charge amount on the developer carrier, and prevent the deterioration of the image quality even after forming tens of thousands of images. .

According to the second aspect of the present invention, since the relative speed of the developer supply member with respect to the developer carrying member is increased by the drive control device at the time of non-development, the development is performed by controlling the drive of the developer supply member. By increasing the relative speed of the developer supply member with respect to the agent carrier to increase the frictional force, the effect of the invention according to claim 1 can be achieved with a simple configuration.

According to the third aspect of the invention, since the drive control device switches the moving direction of the developer supply member with respect to the developer carrying member from the forward direction to the reverse direction during non-developing,
By changing the moving direction of the developer supply member, the relative speed of the developer supply member with respect to the developer carrier is increased to increase the frictional force, and the effect of the invention according to claim 1 is achieved with a simple configuration. You can

According to the fourth aspect of the present invention, the movement of the developer supply member is changed because the drive control device stops the movement of the developer supply member with respect to the movement of the developer carrier during non-development. As a result, the relative speed of the developer supply member with respect to the developer carrier is increased to increase the frictional force, and the effect of the invention according to claim 1 can be achieved with a simple configuration.

According to the fifth aspect of the invention, since the developer supply member is brought closer to the developer carrying member by the position control device at the time of non-development, the developer carrying member is position-controlled to carry the developer carrying member. The relative speed of the developer supply member to the body is increased to increase the frictional force, and the effect of the invention according to claim 1 can be achieved with a simple configuration.

According to the sixth aspect of the present invention, since the developer supply member control device is driven regularly, the deterioration of the developer carrier can be prevented by setting an appropriate time interval for driving the control device. With the above balance, the effect of the invention according to claim 1 can be achieved.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of an internal mechanism in a black-red two-color copying machine according to the present invention.

FIG. 2 is an overall schematic configuration diagram of a second developing device used in the two-color copying machine.

FIG. 3 is a configuration diagram of a drive transmission system to a developer carrier and a developer supply member of the second developing device.

FIG. 4 is an electrical block diagram of a drive transmission system for the developer supply member.

FIG. 5 is a configuration diagram of a position control system of the developer supply member, showing another example of increasing the relative speed of the developer supply member with respect to the developer carrier.

FIG. 6 is an electric block diagram thereof.

[Explanation of symbols]

39 Second developing device (developing device) 48 developer carrier 51 developer supply member 60 Drive control device (developer supply member control device) 70 Position control device (developer supply member control device)

Claims (6)

[Claims] 1. A developing device for supplying a developer to a developer carrying member by a developer supplying member, and adhering the developer by the developer carrying member to develop an electrostatic latent image on the image carrying member. An image forming apparatus, comprising: a developer supply member control device that increases a frictional force of the developer supply member against the developer carrying member during non-development compared to during development. 2. The image forming apparatus according to claim 1, wherein the developer supply member control device includes a drive control device that increases a relative speed of the developer supply member with respect to the developer carrier during non-development. apparatus. 3. The image according to claim 2, wherein the drive control device switches the moving direction of the developer supply member with respect to the developer carrier from a forward direction to a reverse direction to increase the relative speed. Forming equipment. 4. The image forming apparatus according to claim 2, wherein the drive controller stops the movement of the developer supply member with respect to the movement of the developer carrier to increase the relative speed. . 5. The image forming apparatus according to claim 1, wherein the developer supply member control device includes a position control device that brings the developer supply member closer to the developer carrier during non-development. 6. The image forming apparatus according to claim 1, wherein the developer supply member control device is regularly driven.