JP2010164651A - Developing device, image forming apparatus and developing method - Google Patents

Abstract

A physical stress applied to a two-component developer can be suppressed without deteriorating the chargeability of a replenished toner.
A developing device includes a developing tank, a first stirring member, a second stirring member, a developing roller, a developing tank cover, a doctor blade, a partition plate, electromagnets, and toner density detection. A sensor 119 was provided. By rotation of the first stirring member 112 and the second stirring member 113, the two-component developer moves in a circulating manner in the first region 111A and the second region 111B in order. At the time of toner supply, the second stirring member 113 is rotated at a higher speed than the first stirring member 112, and the electromagnets 118A to 118E are energized. In the second region 111B, the two-component developer is sufficiently stirred by receiving a large stirring torque from the second stirring member 113 while being prevented from moving by the magnetic field formed by the electromagnet 118A118E.
[Selection] Figure 2

Description

  The present invention is applied to an image forming apparatus that performs electrophotographic image forming processing using a two-component developer including toner and a magnetic carrier, an image forming apparatus including the developing apparatus, and the developing apparatus. It relates to a developing method.

  2. Description of the Related Art Conventionally, some image forming apparatuses such as copying machines and printers perform electrophotographic image forming processing. An electrophotographic image forming apparatus forms an electrostatic latent image on the surface of a photoreceptor, and develops the electrostatic latent image into a toner image with toner supplied from the developing device to the surface of the photoreceptor at the development position. The toner image is transferred to a sheet such as paper at the transfer position.

  In recent years, two-component developers having excellent toner charging stability have been used for the purpose of achieving full color and high image quality. The two-component developer is composed of a toner and a carrier, and is agitated in the developing device, whereby the toner is charged with a predetermined charge by friction with the carrier. Since only the toner in the two-component developer moves from the developing device to the surface of the photoreceptor when developing the electrostatic latent image, the toner in the two-component developer stored in the developing device as the image forming process is executed The concentration decreases. To maintain the toner concentration in the two-component developer at a reference value or higher, toner is supplied to the developing device.

  In order to meet the demand for speeding up and downsizing of the image forming apparatus, it is necessary to quickly and sufficiently charge the toner in the developing device, and it is necessary to rapidly transport the two-component developer to the developing position. .

  Therefore, in the conventional developing device, the inside of the developing tank is divided into a first area for supplying toner to the photosensitive member and a second area for receiving toner replenishment, and each of the first area and the second area is divided. The two-component developer is circulated and conveyed between the two regions while stirring (see Patent Document 1). According to this configuration, the toner replenished in the developing device can be immediately dispersed in the two-component developer, and an appropriate charge amount can be imparted.

JP-A-10-63081

  In the circulation type developing device, it is desirable to stir the supplied toner and the two-component developer in the developing device for as long as possible in order to stabilize the charged state of the toner. However, if the stirring is continued for a long time, the physical stress applied to the two-component developer increases. For this reason, when the state where the amount of toner replenishment is low, such as when a large number of originals with low toner consumption are continuously printed, the flowability of the developer is reduced, and a sufficient amount of developer is supplied to the photoreceptor. There was a problem that it could not be supplied to the surface.

  About this phenomenon, the fluidity is lowered by burying the toner external additive in the toner particle surface or the carrier particle surface, and between the ear cutting (doctor blade) that regulates the developer supply amount to the photosensitive drum, The cause is thought to be that the developer cannot pass through.

  An object of the present invention is to provide a developing device, an image forming apparatus, and a developing method capable of suppressing physical stress applied to a two-component developer without lowering the charging property of replenished toner.

  In order to solve the above problems, the developing device of the present invention includes a developing tank, a developing roller, a partition plate, a first stirring member, a second stirring member, a magnetic field forming unit, and a control unit. The developing tank contains a two-component developer containing toner and carrier. The developing roller supplies the two-component developer in the developing tank to the surface of the photoreceptor on which the electrostatic latent image is formed. The partition plate divides the inside of the developing tank into a first region where the developing roller is disposed and a second region where toner is supplied, and both ends of the developing roller in the axial direction are open. The first agitating member agitates the two-component developer in the first region while conveying the two-component developer in the first direction along the axial direction. The second agitating member agitates the two-component developer in the second region while conveying the two-component developer in a second direction opposite to the first direction. The magnetic field forming means forms a magnetic field in the second region. The control means, when replenishing the toner to the second region, makes the conveyance speed of the two-component developer by the second stirring member faster than the conveyance speed when the toner is not replenished, and operates the magnetic field forming means.

  In this configuration, when the toner is replenished, the rotational speed of the second stirring member is increased, and the triboelectric charging property between the toner replenished in the second region and the two-component developer remaining in the developing tank is improved. Even when the toner replenishment amount is large, a stable toner charge amount can be obtained. In addition, since the magnetic field is formed in the second region by the magnetic field forming unit when the toner is replenished, the developer conveyance speed is reduced, and the two-component developer is not biased to the downstream side of the second stirring member. In addition, the rotational speed of the second stirring member is reduced except during toner replenishment, so that excessive physical stress does not act on the two-component developer, and the fluidity of the two-component developer does not decrease. .

  In this configuration, it is preferable that the control unit intermittently operates the magnetic field forming unit when the toner is supplied.

  Moreover, it is preferable to arrange the magnetic field forming means vertically below the second stirring member on the bottom surface of the developing tank.

  Furthermore, it is preferable to divide and arrange the magnetic field forming means at a plurality of positions in the axial direction.

  An image forming apparatus according to the present invention includes the above-described developing device and a photoconductor that receives supply of a two-component developer from the developing device after an electrostatic latent image is formed on the surface.

  According to the developing method of the present invention, when the toner is supplied to the second area, the conveyance speed of the two-component developer in the second area is made faster than the conveyance speed when the toner is not supplied, and a magnetic field is generated in the second conveyance path. It is characterized by forming.

  According to this developing method, when the toner is replenished, the rotation speed of the second stirring member is increased, and the triboelectric charge between the toner replenished in the second region and the two-component developer remaining in the developing tank is increased. Can be improved. For this reason, a stable toner charge amount can be obtained even when the toner replenishment amount is large. Further, since the magnetic field is formed in the second region by the magnetic field forming means when the toner is replenished, the developer conveyance speed can be reduced, and the two-component developer is biased to the downstream side of the second stirring member. Can be prevented. Furthermore, by reducing the rotation speed of the second stirring member other than during toner replenishment, it is possible to prevent excessive physical stress from acting on the two-component developer and maintain good fluidity of the two-component developer. .

  According to the present invention, a stable toner charge amount can be obtained even when the amount of toner replenishment is large, and a decrease in developer fluidity due to developer stress can be suppressed except during toner replenishment. .

1 is a schematic cross-sectional view of an image forming apparatus using a developing device according to an embodiment of the present invention. FIG. 2 is a front sectional view of the developing device. It is sectional drawing of the XX part in FIG. It is sectional drawing of the YY part in FIG. FIG. 3 is a side sectional view of the toner supply device. It is sectional drawing of the ZZ part in FIG. FIG. 2 is a block diagram of a control unit provided in the developing device. FIG. 4 is a cross-sectional view showing a state of a two-component developer in a developing tank when toner is not replenished. FIG. 3 is a cross-sectional view showing a state of a two-component developer in a developing tank when toner is supplied.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an image forming apparatus using a developing device according to an embodiment of the present invention. The image forming apparatus 100 can form a full color image on a sheet by electrophotographic image forming processing using toners of four colors of black, cyan, magenta, and yellow. Therefore, the image forming apparatus 100 includes the exposure unit 1 in addition to the four photosensitive drums 3a to 3d, the developing devices 2a to 2d, the cleaners 4a to 4d, the chargers 5a to 5d, and the primary transfer rollers 6a to 6d. An intermediate transfer belt unit 8, a secondary transfer roller 11, and a fixing unit 12.

  The image forming apparatus 100 includes four image forming stations each including four photosensitive drums 3a to 3d, developing devices 2a to 2d, cleaners 4a to 4d, chargers 5a to 5d, and primary transfer rollers 6a to 6d. It is configured. Each of the four image forming stations forms toner images of each color of black, cyan, magenta, and yellow.

  As an example, in an image forming station that forms a black toner image, the surface of the photosensitive drum 3a is uniformly charged by the charger 5a, and then exposed from the exposure unit 1 by laser light modulated with black image data. Then, an electrostatic latent image of a black image is formed. The electrostatic latent image formed on the surface of the photosensitive drum 3a is visualized as a toner image by black toner supplied from the developing device 2a. The developing device 2a includes a toner replenishing device 22a, and stores a two-component developer composed of black toner and a carrier.

  The image is transferred onto the surface of the intermediate transfer belt 7 of the intermediate transfer belt unit 8 by the primary transfer roller 6a. After the toner image is transferred to the intermediate transfer belt 7, the toner remaining on the surface of the photosensitive drum 3a is removed and collected by the cleaner 4a.

  Other image forming stations that form toner images of cyan, magenta, and yellow are configured similarly to the image forming station that forms a black toner image. However, the photosensitive drums 3b to 3d are exposed from the exposure unit 1 by laser light modulated with image data of each color of cyan, magenta, and yellow, respectively. The developing devices 2b to 2d supply cyan, magenta, and yellow toners to the surfaces of the photosensitive drums 3b to 3d, respectively.

  When forming a color image, the toner images formed at the four image forming stations are sequentially transferred onto the intermediate transfer belt 7 from each of the photosensitive drums 3a to 3d and transferred onto the intermediate transfer belt 7 by subtractive color mixing. A full color image is formed.

  In the intermediate transfer belt unit 8, an endless intermediate transfer belt 7 is stretched between a driving roller 71 and a driven roller 72. The intermediate transfer belt 7 moves between each of the photosensitive drums 3a to 3d and each of the primary transfer rollers 6a to 6d by the rotation of the driving roller 71.

  The secondary transfer roller 11 is disposed at a position where the intermediate transfer belt is sandwiched between the secondary transfer roller 11 and the drive roller 71 in the paper transport path S. The secondary transfer roller 11 transfers the toner image from the surface of the intermediate transfer belt 7 to the paper fed from the paper feed cassette 10 or the manual feed tray 20.

  In the paper transport path S, a registration roller 14, paper feed rollers 16a and 16b, and transport rollers 25a to 25h are arranged. The paper transport path S is a main transport path from the paper feed cassette 10 through the fixing unit 12 to the transport roller 25c, a sub transport path that joins the manual feed tray 20 to the main transport path, and a join from the transport roller 25c to the main transport path. Including a reversing conveyance path.

  The fixing unit 12 includes a heating roller 81 and a pressure roller 82. The fixing unit 12 heats and pressurizes the sheet on which the toner image conveyed via the main conveyance path is transferred, and fixes the toner image on the surface of the sheet.

  2 is a front sectional view of the developing device, FIG. 3 is a sectional view taken along a line XX in FIG. 2, and FIG. 4 is a sectional view taken along a line YY in FIG. The developing device 2a includes a developing tank 111, a second stirring member 112, a first stirring member 113, a developing roller 114, a developing tank cover 115, a doctor blade 116, a partition plate 117, and a toner concentration detection sensor 119.

  The developing tank 111 contains a two-component developer containing toner and a carrier. The developing tank 111 is divided into a first region 111A and a second region 111B by a partition plate 117. A first stirring member 112 and a developing roller 114 are pivotally supported in the first region 111A. A second stirring member 113 is pivotally supported in the second region 111B.

  The developing roller 114 is a magnet roller that rotates about an axis parallel to the rotation axis of the photosensitive drum 3a by a driving unit (not shown), and conveys the two-component developer in the developing tank 111 to the surface of the photosensitive drum 3a. . The developing roller 114 is disposed at a position facing the photosensitive drum 3a with a gap between the developing roller 114 and the surface of the photosensitive drum 3a. The two-component developer conveyed by the developing roller 114 comes into contact with the photosensitive drum 3 at the developing position closest to the photosensitive drum 3a. Toner is supplied from the two-component developer on the surface of the developing roller 114 to the electrostatic latent image on the surface of the photosensitive drum 3a by a developing bias voltage applied to the developing roller 114 from a power source (not shown).

  The doctor blade 116 is a plate-like member extending parallel to the axial direction of the developing roller 114, and one end in the short direction is supported by the developing tank 111 and the other end is the developing roller 114 below the developing roller 114 in the vertical direction. It is provided so as to be separated from the surface with a gap. As the material of the doctor blade 116, stainless steel can be used, but aluminum or synthetic resin can also be used.

  The toner concentration detection sensor 119 is attached to the bottom surface of the second region 111 </ b> A in the developing tank 111, and is provided so that the sensor surface is exposed inside the developing tank 111. The toner concentration detection sensor 119 is electrically connected to a toner concentration control means (not shown). The toner density control means controls to supply toner from the toner replenishing device 22a (see FIG. 1) into the second region 111B in accordance with the toner density measurement value detected by the toner density detection sensor 119.

  If it is determined that the toner density measurement value by the toner density detection sensor 119 is lower than the toner density setting value, a control signal is sent to the driving means for driving the toner discharge member 122 to rotate, and the toner discharge member 122 is driven to rotate. As the toner concentration detection sensor 119, a general toner concentration detection sensor can be used. For example, a transmitted light detection sensor, a reflected light detection sensor, a magnetic permeability detection sensor, and the like can be used. In particular, a magnetic permeability detection sensor is preferable. .

  A power supply (not shown) is connected to the magnetic permeability detection sensor. The power supply applies a drive voltage for driving the magnetic permeability detection sensor and a control voltage for outputting the detection result of the toner density to the control means. Application of a voltage to the magnetic permeability detection sensor by the power source is controlled by the control means. The permeability detection sensor is a type of sensor that receives the control voltage and outputs the toner density detection result as an output voltage value. Basically, the sensitivity near the median value of the output voltage is good. It is used by applying a control voltage to obtain a voltage.

  A removable developing tank cover 115 is provided on the upper side of the developing tank 111. A toner supply port 115 a is formed in the developing tank cover 115. The toner accommodated in the toner replenishing device 22a is conveyed into the second region 111B via the toner transfer mechanism 102 and the toner supply port 115.

  The first stirring member 112 is configured by a screw auger including a spiral first conveying blade 112A and a first rotating shaft 112B. The second agitating member 113 is configured by a screw auger including a spiral second conveying blade 113A and a second rotating shaft 113B. The first stirring member 112 and the second stirring member 113 are configured to stir and convey the two-component developer by rotating.

  In the developing tank 111, a partition plate 117 is disposed between the first stirring member 112 and the second stirring member 113. The partition plate 117 extends in parallel with each axial direction (each rotational axis direction) of the first stirring member 112 and the second stirring member 113. The interior of the developing tank 111 is partitioned by a partition plate 117 into a first region 111A in which the first stirring member 112 is disposed and a second region 111B in which the second stirring member 113 is disposed.

  The partition plate 117 is disposed away from the inner wall surface of the developing tank 111 at both axial ends of the first stirring member 112 and the second stirring member 113. Thereby, in the developing tank 111, in the vicinity of both axial end portions of the first stirring member 112 and the second stirring member 113, communication paths 117A and 117B communicating the first region 111A and the second region 111B. Is formed.

  The first stirring member 112 and the second stirring member 113 are arranged in parallel so that their peripheral surfaces face each other via the partition plate 117 and their axes are parallel to each other, and rotate in opposite directions. Is set to The first stirring member 112 transports the two-component developer in the direction of arrow P, and the second stirring member 113 transports the two-component developer in the direction of arrow Q opposite to the direction of arrow P.

  The toner supply port 115A is formed in the second region 111B and at a position closer to the arrow P direction than the communication path 117B. Accordingly, the toner is replenished downstream of the communication path 117B in the second region 111B.

  A plurality of electromagnets 118 </ b> A to 118 </ b> E are provided at a position corresponding to a lower portion of the second region 111 </ b> B at the bottom of the developing tank 111. The electromagnets 118 </ b> A to 118 </ b> E are the magnetic field forming means of the present invention. The electromagnets 118 </ b> A to 118 </ b> E form a magnetic field by flowing current and flow of the two-line developer in the second region 111 </ b> B Suppress. The electromagnets 118 </ b> A to 118 </ b> E operate in conjunction with the rotation speed of the second stirring member 113 when toner is supplied. The magnetic field formed by the electromagnets 118A to 118E is intermittently formed.

  In the developing tank 111, the first stirring member 112 and the second stirring member 113 are rotationally driven by a motor 122 and a motor 123, respectively.

  In the first region 111A, the two-component developer is conveyed in the arrow P direction (first direction) while being stirred by the first stirring member 112, and reaches the communication path 117B. The two-component developer that has reached the communication path 117B passes through the communication path 117B and is conveyed to the second region 111B.

  On the other hand, in the second region 111B, the two-component developer is conveyed in the arrow Q direction (second direction) while being stirred by the second stirring member 113, and reaches the communication path 117A. The two-component developer that has reached the communication path 117A passes through the communication path 117A and is conveyed to the first region 111A.

  In this way, the two-component developer moves in the developing tank 111 by circulating in the first area 111A, the communication path 117B, the second area 111B, and the communication path 117A in this order. The two-component developer is carried on the surface by the rotation of the developing roller 114 while being transported in the first region 111A, and the toner in the two-component developer moves to the surface of the photosensitive drum 3a. Then, it is consumed sequentially.

  In order to supplement the toner consumed in the image forming process, unused toner is replenished from the toner supply port 115A into the second region 111B. The replenished toner is mixed and stirred with the two-component developer that has been present in the second region 111B.

  FIG. 5 is a side sectional view of the toner supply device. 6 is a cross-sectional view taken along the line ZZ in FIG. The toner supply device 22 a includes a toner storage container 121, a toner stirring member 125, a toner discharge member 122, and a toner discharge port 123.

  The toner replenishing device 22a is disposed on the upper side of the developing tank 111 and stores unused toner. The toner in the toner replenishing device 22 is supplied from the toner discharge port 123 to the developing tank 111 through the toner transfer mechanism 102 by the rotation of the toner discharge member 122.

  The toner container 121 has a substantially semi-cylindrical shape, and rotatably supports the toner stirring member 125 and the toner discharge member 122. The toner discharge port 123 is a substantially rectangular opening provided below the toner discharge member 122 and from the central portion in the axial direction, and is disposed at a position facing the toner transfer mechanism 102.

  The toner stirring member 125 is a plate-like member, and includes a toner scooping member 125B at the tip. The toner agitating member 125 rotates around the rotation shaft 125 </ b> A to draw up and convey the toner stored in the toner storage container 121 to the toner discharge member 122 while stirring the toner. The toner pumping member 125 </ b> B is made of a polyethylene terephthalate (PET) sheet having flexibility, and is attached to both ends of the toner stirring member 125.

  The toner discharging member 122 includes a toner conveying blade 122A and a toner discharging member rotating shaft 122B, and supplies the toner in the toner container 121 to the developing tank 111 from the toner discharging port 123. The toner discharge member 122 is rotated by a motor 134. The direction of the toner transport blade 122A is set so that the toner is transported from both axial ends of the toner discharge member 122 toward the toner discharge port 123 side.

  A toner discharge member partition wall 124 is provided between the toner discharge member 122 and the toner stirring member 125. As a result, an appropriate amount of toner pumped up by the toner stirring member 125 is present around the toner discharge member 122.

  The toner stirring member 125 rotates in the direction of the arrow, stirs the toner, and pumps the toner toward the toner discharge member 122. At this time, the toner scooping member 125 </ b> B rotates while sliding and deforming the inner wall of the toner container 121 due to its flexibility, and supplies the toner to the toner discharge member 122. The toner discharge member 122 guides the supplied toner to the toner discharge port 123 by rotation.

  FIG. 7 is a block diagram of a control unit provided in the developing device. The control unit 200 is a control unit of the present invention, and is configured by connecting a toner density sensor 119, motor drivers 202 to 204, a power supply controller 205, and a rotation detection sensor 206 to a CPU 201. The motor drivers 202 to 204 drive the motors 132 to 134. The controller 205 applies a voltage to the electromagnets 118A to 118E. The rotation detection sensor 206 detects the rotation speed of the toner discharge member 122. The rotation detection sensor 206 may detect a signal (pulse) used when driving the 134.

  The CPU 201 outputs data instructing the motor drivers 202 and 203 to rotate at a steady speed during the image forming process in the image forming apparatus 100. Motor drivers 202 and 203 rotate motors 132 and 133 at a steady speed. As a result, the first stirring member 112 and the second stirring member 113 rotate at a steady speed that does not require toner replenishment.

  When the toner concentration sensor 119 detects a decrease in toner concentration in the two-component developer, the CPU 201 outputs data that instructs the motor driver 204 to drive the motor 134. The motor driver 204 rotates the motor 134 based on the drive data from the CPU 201, so that the toner is supplied into the developing tank 111.

  The CPU 201 controls the rotation of the toner discharge member 122 based on the detection signal of the rotation detection sensor 206. When the toner is supplied to the developing tank 111, the CPU 201 causes the motor driver 203 to increase the rotation speed of the motor 133 so that the rotation speed ratio between the first stirring member 112 and the second stirring member 113 becomes a predetermined value. Change the drive data to

  The rotation speed ratio between the first stirring member 112 and the second stirring member 113 is preferably 1.5 or more and 3 or less. When the rotation speed ratio is less than 1.5, the effect of suppressing image density reduction and fogging can be obtained even when a large number of images with high toner consumption are printed continuously while suppressing wear and deterioration of the two-component developer. It's hard to be done. When the rotation speed ratio exceeds 3, the toner charge amount changes greatly, and image density unevenness is likely to occur.

  The CPU 201 further supplies drive data to the controller 205, applies a voltage to the electromagnets 118A to 118E, and generates an electric field in the second region 111B.

  When the CPU 201 determines that the toner supply has been completed based on the detection signal of the toner concentration sensor 119 or the rotation detection sensor 206, the CPU 201 returns the rotation speed of the second stirring member 113 to the steady speed and energizes the electromagnets 118A to 118E. Shut off.

  FIG. 8 is a cross-sectional view showing the state of the two-component developer in the developing tank when the toner is not replenished, and FIG. 9 is a cross-sectional view showing the state of the two-component developer in the developing tank when the toner is replenished. When the toner is supplied into the developing tank 111, the second stirring member 113 is rotated at a high speed, and the electromagnets 118A to 118E form a magnetic field in the second region 111B. For this reason, when the toner is replenished, a magnetic brush is formed in the two-component developer, and the flow of the two-component developer is suppressed. In addition, when the toner is replenished, the rotation speed of the second agitating member 113 is faster than the steady rotation speed when the toner is not replenished, and a larger agitation torque acts on the two-component developer than when the toner is not replenished. is doing. Therefore, at the time of toner supply, the toner supplied to the second region 111B is sufficiently stirred with the existing two-component developer.

  Although the developing device 2a has been described in the above embodiment, the same applies to the developing devices 2b to 2d.

  The developing device and the developing method of the present invention are applicable not only to an image forming apparatus capable of forming a full-color image but also to an image forming apparatus that forms a single color image on condition that an electrophotographic image forming process is performed. can do.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

2a to 2d-developing devices 3a to 3d-photosensitive drum 100-image forming apparatus 111-developing tank 111A-first region 111B-second region 112-first stirring member 113-second stirring member 114-developing roller 117-partition plates 118A to 118E-electromagnet (magnetic field forming means)

Claims (6)

A developer tank containing a two-component developer containing toner and carrier;
A developing roller for supplying the two-component developer in the developing tank to the surface of the photoreceptor on which the electrostatic latent image is formed;
A partition plate that divides the inside of the developing tank into a first region in which the developing roller is disposed and a second region in which toner is supplied; and a partition plate in which both ends in the axial direction of the developing roller are open ,
A first agitating member for agitating while conveying the two-component developer in the first direction along the axial direction in the first region;
A second agitating member that agitates the two-component developer in the second region while conveying the two-component developer in a second direction opposite to the first direction;
Magnetic field forming means for forming a magnetic field in the second region;
Control means for operating the magnetic field forming means while making the conveyance speed of the two-component developer by the second stirring member faster than the conveyance speed when the toner is not replenished when replenishing the toner to the second region;
A developing device comprising:   The developing device according to claim 1, wherein the control unit intermittently operates the magnetic field forming unit when the toner is supplied.   The developing device according to claim 1, wherein the magnetic field forming unit is disposed vertically below the second stirring member on a bottom surface of the developing tank.   The developing device according to claim 1, wherein the magnetic field forming unit is divided and arranged at a plurality of positions in the axial direction. A developing device according to any one of claims 1 to 4,
A photoreceptor that receives supply of a two-component developer from the developing device after an electrostatic latent image is formed on the surface;
An image forming apparatus. The two-component developer containing the toner and the carrier is passed through the first stirring member and the second stirring member respectively disposed in the first region and the second region in the developing tank. In the developing method in which the region and the second region are circulated and agitated while being conveyed and supplied to the surface of the photoreceptor through the developing roller disposed in the first region,
A developing method in which, when toner is supplied to the second area, the conveying speed of the component developer in the second area is made faster than the conveying speed when toner is not supplied, and a magnetic field is formed in the second conveying path. .

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