JP6828489B2 - Control method of developing device, image forming device, developing device - Google Patents

Description

The present disclosure relates to a developing apparatus, an image forming apparatus, and a method for controlling the developing apparatus.

Electrophotograph type image forming apparatus is widespread. In the electrophotographic image forming apparatus, the electrostatic latent image formed on the photoconductor is developed by supplying the developing agent to the photoconductor from the developing apparatus. The developing apparatus includes a developing roller that supports and conveys the developing agent, and a regulating member for adjusting the amount of the developing agent conveyed.

When the developer adheres to the regulating member, the gap between the regulating member and the developing roller is reduced, and the amount of the developing agent conveyed by the developing roller is reduced. Japanese Patent Application Laid-Open No. 2015-0366699 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2011-013248 (Patent Document 2) disclose a technique for recovering a developer adhering to a regulatory member.

Japanese Unexamined Patent Publication No. 2015-0366699 Japanese Unexamined Patent Publication No. 2011-013248

In the techniques disclosed in Patent Documents 1 and 2 described above, the developer adhering to the surface of the regulating member is recovered by forming a developer pool on the surface of the regulating member. However, these techniques cannot always sufficiently remove the developer from the surface of the regulating member, and further improvement is required.

The present disclosure provides a developing device, an image forming device, and a method for controlling the developing device, which can suppress the adhesion of the developing agent to the surface of the regulating member.

According to one aspect of the present disclosure, there is provided a developing apparatus used in an image forming apparatus that forms an image using a developer. The developing apparatus includes a developing roller, a regulating member, and a control unit. The developing roller has a developing sleeve and a plurality of magnetic poles. The developing sleeve has a cylindrical shape. The plurality of magnetic poles are arranged along the inner peripheral surface of the developing sleeve. The regulating member regulates the thickness of the developer on the outer peripheral surface of the developing sleeve. The control unit controls the operation of the developing device. The developer forms a magnetic brush on the outer peripheral surface of the developing sleeve. The control unit executes a cleaning process at the time of non-image formation of the image forming apparatus. The cleaning process is a process of rotating the developing sleeve in a state where the magnetization of the magnetic brush formed at the position facing the regulating member is higher than that at the time of image formation of the image forming apparatus.

In the above developing apparatus, the developing agent includes toner and a carrier, and the control unit lowers the toner concentration of the developing agent passing through the position facing the regulating member when the image forming apparatus is not forming an image.

In the above-mentioned developing apparatus, the image forming apparatus includes a photoconductor. The control unit prints toner on the photoconductor at a higher density than when the image forming apparatus forms an image when the image forming apparatus does not form an image.

In the above-mentioned developing apparatus, the control unit prints toner on the photoconductor during non-image forming of the image forming apparatus, peels off the developer having a reduced toner concentration from the developing roller, and then supplies the toner to the developing roller again.

In the above developing apparatus, the plurality of magnetic poles have a catch electrode for holding the developer on the developing sleeve and a peeling electrode for peeling the developer from the developing sleeve. The control unit moves the peeling electrode to bring it closer to the catching electrode when the image forming apparatus is not forming an image.

The developing apparatus further includes a supply roller that supplies the developing agent to the developing roller by rotating. The control unit stops the rotation of the supply roller during non-image formation of the image forming apparatus.

In the above developing apparatus, the control unit rotates the developing sleeve to print toner on the photoconductor when the image forming apparatus is not forming an image, and then rotates the developing sleeve in the reverse direction.

In the above developing apparatus, the developing roller further has a magnet roller rotatably provided with respect to the inner peripheral surface of the developing sleeve. The plurality of magnetic poles are arranged side by side in the circumferential direction of the magnet roller. The plurality of magnetic poles have a regulating pole arranged at a position facing the regulating member at the time of image formation of the image forming apparatus, and another magnetic pole having a magnetic flux density higher than that of the regulating pole. The control unit moves the other magnetic poles to a position facing the regulating member during non-image formation of the image forming apparatus.

In the above developing apparatus, the other magnetic poles are the main poles arranged at positions facing the photoconductor during image formation of the image forming apparatus.

In the above-mentioned developing apparatus, the control unit moves the other magnetic poles to a position facing the regulating member, and then rotates the developing sleeve in a direction opposite to the rotation direction of the image forming apparatus at the time of image formation.

In the above-mentioned developing apparatus, the control unit executes the cleaning process when the cumulative number of prints by the developing apparatus or the number of prints since the previous execution of the cleaning process reaches a predetermined number.

According to one aspect of the present disclosure, an image forming apparatus comprising a photoconductor and any of the above developing apparatus is provided.

According to one aspect of the present disclosure, there is provided a method of controlling a developing device provided in an image forming device that forms an image using a developer. The developing apparatus includes a developing roller and a regulating member. The developing roller has a developing sleeve and a plurality of magnetic poles. The developing sleeve has a cylindrical shape. The plurality of magnetic poles are arranged along the inner peripheral surface of the developing sleeve. The regulating member regulates the thickness of the developer on the outer peripheral surface of the developing sleeve. The developer forms a magnetic brush on the outer peripheral surface of the developing sleeve. The control method includes a step of determining whether or not it is the time of image formation of the image forming apparatus, and a step of executing a cleaning process when it is determined in the determination step that the image forming apparatus is not forming an image. There is. The cleaning process is a process of rotating the developing sleeve in a state where the magnetization of the magnetic brush formed at the position facing the regulating member is higher than that at the time of image formation of the image forming apparatus.

In the above control method, the developer contains toner and carriers. The step of performing the cleaning process includes a step of reducing the toner concentration of the developer passing through the position facing the regulating member.

In the above control method, the image forming apparatus includes a photoconductor. The step of performing the cleaning process includes printing the toner on the photoconductor at a higher density than that at the time of image formation of the image forming apparatus.

In the above control method, the steps of executing the cleaning process are a step of printing the toner on the photoconductor, a step of peeling the developer having a reduced toner concentration from the developing roller, and a step of peeling the toner from the developing roller. It includes the step of resupplying the developer to the developing rollers.

In the above control method, the plurality of magnetic poles have a catch electrode for holding the developer on the developing roller and a release electrode for peeling the developer from the developing sleeve. The step of performing the cleaning process includes moving the peeling electrode closer to the catching electrode.

In the above control method, the developing apparatus further includes a supply roller that supplies the developing agent to the developing roller by rotating. The step of performing the cleaning process includes a step of stopping the rotation of the supply roller.

In the above control method, the step of performing the cleaning process includes a step of rotating the developing sleeve to print the toner on the photoconductor, and a step of rotating the developing sleeve in the opposite direction after the step of printing. ..

In the above control method, the developing roller further includes a magnet roller rotatably provided with respect to the inner peripheral surface of the developing sleeve. The plurality of magnetic poles are arranged side by side in the circumferential direction of the magnet roller. The plurality of magnetic poles have a regulating pole arranged at a position facing the regulating member at the time of image formation of the image forming apparatus, and another magnetic pole having a magnetic flux density higher than that of the regulating pole. The step of performing the cleaning process includes moving the other magnetic poles to a position facing the regulating member.

In the above control method, the other magnetic poles are the main poles arranged at positions facing the photoconductor during image formation of the image forming apparatus.

In the above control method, the step of executing the cleaning process includes a step of moving the other magnetic poles to a position facing the regulating member, and after the step of moving the developing sleeve, the rotation direction of the image forming apparatus at the time of image formation. Includes a step of rotating in the opposite direction.

In the above control method, when the cumulative number of prints by the developing device or the number of prints since the previous execution of the cleaning process reaches a predetermined number, the cleaning process is executed.

According to the developing apparatus according to the present disclosure, the image forming apparatus provided with the developing apparatus, and the control method of the developing apparatus, it is possible to suppress the adhesion of the developer to the surface of the regulating member.

It is a schematic diagram which shows the structure of the image forming apparatus which uses the developing apparatus in embodiment. It is a partial cross-sectional view which shows the structure of the developing apparatus in embodiment. It is a side view which shows the structure of a developing roller and a regulation member. It is a schematic diagram which shows the behavior of the developer at the time of normal image formation of an image forming apparatus. It is a schematic diagram which shows about the magnetic brush. It is a block diagram which shows the outline of the system structure of a developing apparatus. It is a schematic diagram which shows the regulation member at the time of starting use of a developing apparatus. It is a schematic diagram which shows the adhesion of the developer to the tip of a regulation member. It is a schematic diagram which shows the regulation member after a lapse of time. It is a flowchart explaining the condition for executing the cleaning process of a regulation member. It is the first figure explaining the cleaning of the regulation member in Embodiment 1. FIG. It is a 2nd figure explaining the cleaning of the regulation member in Embodiment 1. FIG. It is a flowchart which shows the 1st means which re-catch a developer. It is a schematic diagram which shows the movement of the peeling electrode in a magnet roller. It is a schematic diagram which shows the developer in a housing at the time of normal image formation. It is a flowchart which shows the 2nd means of catching a developer again. It is a schematic diagram which shows the developer in the housing when the supply roller is stopped. It is a flowchart explaining the cleaning of the regulation member in Embodiment 2. It is a schematic diagram which shows the toner density decrease of the developer on the outer peripheral surface of a developing roller. It is a schematic diagram of a state in which a developer having a reduced toner concentration faces a regulating member. It is a flowchart explaining the cleaning of the regulation member in Embodiment 3. It is a schematic diagram which shows the rotation of a magnet roller. It is a graph which shows the change of the developer transport amount with respect to the number of prints in an Example and a comparative example.

Hereinafter, the control method of the developing device, the image forming device, and the developing device according to the embodiment will be described with reference to the drawings. In the embodiments shown below, the same or substantially the same configuration will be designated by the same reference numerals, and duplicate description will not be repeated. Each configuration of the embodiments and modifications described below may be selectively combined as appropriate.

(Embodiment 1)
(Image forming apparatus 100)
FIG. 1 is a schematic view showing the configuration of the image forming apparatus 100. With reference to FIG. 1, the schematic configuration of the image forming apparatus 100 in which the developing apparatus 5 in the embodiment is used will be described. The image forming apparatus 10 may be, for example, a color printer, a monochrome printer, or a monochrome printer, a color printer, and a multi-function peripheral peripheral (MFP).

The photoconductor 1 is an image carrier that supports a toner image. Around the photoconductor 1, a cleaning device 2, a charging device 3, a writing device 4 (in the figure, only an arrow indicating scanning light from the writing device is shown), and a developing device 5 (in FIG. 1, a developing roller 11 and a regulating member 12 are shown). A recording material 6 such as a transfer belt is arranged. Well-known devices such as a paper feeding device and a fixing device are also provided, but the description thereof is omitted here.

The photoconductor 1, the charging device 3, and the developing roller 11 are rotationally driven by a driving means (not shown), and the recording material 6 is conveyed. The rotation directions R1, R2 and R3 shown in FIG. 1 indicate the directions in which each of the photoconductor 1, the charging device 3 and the developing roller 11 rotates during normal image formation of the image forming apparatus 100, and are shown in FIG. The transport direction DR1 indicates the direction in which the recording material 6 is transported during normal image formation of the image forming apparatus 100.

The charging device 3 uniformly charges the surface of the photoconductor 1. The surface of the charged photoconductor 1 is irradiated with scanning light from the writing device 4. As a result, an electrostatic latent image is formed on the surface of the photoconductor 1. A developer is supplied from the developing device 5 to the electrostatic latent image, and the toner image is visualized on the surface of the photoconductor 1. The toner image is transferred from the surface of the photoconductor 1 to the recording material 6. The cleaning device 2 collects the toner remaining on the surface of the photoconductor 1 after the transfer of the toner image.

The developer is a two-component developer containing toner and carriers. As the toner, a toner obtained by adhering an external additive to the toner matrix particles is used. The toner is formed of a non-magnetic material, and the carrier is formed of a magnetic material.

(Developer 5)
FIG. 2 is a partial cross-sectional view showing the configuration of the developing apparatus 5 according to the embodiment. The configuration of the developing apparatus 5 provided in the image forming apparatus 100 shown in FIG. 1 will be described with reference to FIG.

The developing device 5 is a two-component developing device that develops an electrostatic latent image on the photoconductor 1, and converts the electrostatic latent image into a visible toner image by reverse development with negatively charged toner particles.

The developing device 5 has a housing 15 that houses the developing agent. A developing roller 11, a supply roller 13, and a stirring and transporting member 14 are housed in a predetermined position inside the housing 15 so as to be rotatable about a rotation axis with respect to the housing 15. The developing roller 11, the supply roller 13, and the stirring and transporting member 14 are arranged in parallel along the extending direction of each rotation axis (the direction perpendicular to the paper surface in FIG. 2).

The stirring and transporting member 14 rotates in the housing 15 to stir the developer and transport the developer to the supply roller 13. The supply roller 13 receives the developer conveyed from the stirring and conveying member 14, and supplies the developer toward the developing roller 11. The developer circulates between the stirring and transporting member 14 and the feeding roller 13 by rotating the stirring and transporting member 14 and the supply roller 13 in opposite directions.

A regulating member 12 is arranged at a position facing a predetermined portion on the outer peripheral surface of the developing roller 11. One end of the regulating member 12 is fixed to the housing 15. The other end of the regulating member 12 is provided so as to face the outer peripheral surface of the developing roller 11. The regulating member 12 has, for example, a flat plate shape, and the small end surface is arranged so as to be orthogonal to the outer peripheral surface of the developing roller 11. The regulating member 12 is arranged away from the outer peripheral surface of the developing roller 11. A gap is formed between the regulating member 12 and the developing roller 11.

FIG. 3 is a side view showing the configurations of the developing roller 11 and the regulating member 12. As shown in FIG. 3, the developing roller 11 includes a magnet roller 20 and a developing sleeve 21. The magnet roller 20 has a solid cylindrical outer shape and has an outer peripheral surface 20A. The developing sleeve 21 has a hollow cylindrical shape, and has an inner peripheral surface 21A and an outer peripheral surface 21B. The magnet roller 20 is housed in the developing sleeve 21.

The magnet roller 20 is rotatably provided with respect to the developing sleeve 21 by a bearing (not shown). The magnet roller 20 is rotatably provided with respect to the inner peripheral surface 21A of the developing sleeve 21. The developing sleeve 21 is rotatably provided with respect to the outer peripheral surface 20A of the magnet roller 20. The magnet roller 20 and the developing sleeve 21 can rotate relative to each other.

The magnet roller 20 and the developing sleeve 21 can rotate separately. The magnet roller 20 is rotatable and the developing sleeve 21 is also rotatable by receiving a rotational driving force from a drive source (not shown). The magnet roller 20 and the developing sleeve 21 can rotate in both the clockwise direction and the counterclockwise direction in the drawing, respectively. As the drive source of the magnet roller 20, for example, it is preferable to use a device that can drive forward and reverse rotation and can control the rotation position, such as a stepping motor.

The magnet roller 20 has a plurality of magnetic poles. The plurality of magnetic poles are contained in the magnet roller 20. The plurality of magnetic poles are arranged along the inner peripheral surface 21A of the developing sleeve 21. The plurality of magnetic poles are arranged side by side in the circumferential direction of the magnet roller 20 and the developing sleeve 21. In the present embodiment, five poles of a catch pole 22, a transport pole 23, a regulation pole 24, a main pole 25, and a peeling pole 26 are provided. With reference to FIG. 2, the catch pole 22, the regulation pole 24 and the peel pole 26 are S poles, and the transport pole 23 and the main pole 25 are N poles. On the surface of the magnet roller 20, the magnetism of the S pole and the magnetism of the N pole are alternately arranged.

The catch electrode 22 attracts the developer supplied from the supply roller 13 by magnetic force, and holds the developer on the outer peripheral surface 21B of the developing sleeve 21. After that, the developer on the outer peripheral surface 21B of the developing sleeve 21 is conveyed to the conveying electrode 23 while being supported on the outer peripheral surface 21B of the developing sleeve 21. The developer is maintained in a state of being attached to the outer peripheral surface 21B of the developing sleeve 21 by the transport electrode 23.

The regulating electrode 24 is arranged at a position where the outer peripheral surface of the developing roller 11 or the outer peripheral surface 21B of the developing sleeve 21 faces the regulating member 12. When the developer that receives the magnetic force from the regulating electrode 24 passes through the gap between the developing roller 11 and the regulating member 12, the regulating member 12 regulates the thickness of the developing sleeve 21 on the outer peripheral surface 21B. .. Since the developer is scraped off by the regulating member 12, the uniformity of the amount of the developer conveyed is improved.

The developer is conveyed to the main electrode 25 after passing through the regulation electrode 24. The main pole 25 is arranged at a position facing the photoconductor 1 (FIG. 1). The main pole 25 is configured to have a higher magnetic flux density than the regulation pole 24. When the developer passes through the position of the main pole 25, only the toner among the toner and the carrier contained in the developer adheres to the photoconductor 1. As a result, the electrostatic latent image formed on the photoconductor 1 is developed as a toner image.

After that, the developer remaining on the outer peripheral surface 21B of the developing sleeve 21 is conveyed to the peeling electrode 26 of the magnet roller 20. The peeling electrode 26 is a magnetic pole for peeling the developer from the developing sleeve 21. The developer that has reached the peeling pole 26 tries to move to the catch pole 22 on the downstream side in the rotational direction by the conveying force of the developing sleeve 21, but since the peeling pole 26 is the S pole and the catch pole 22 is also the S pole. , A repulsive force acts between the peeling electrode 26 and the catch electrode 22, and the developer cannot move to the catch electrode 22. As a result, the developer peels off from the developing sleeve 21 and falls into the lower housing 15.

FIG. 4 is a schematic view showing the behavior of the developer during normal image formation of the image forming apparatus 100. The developer D1 shown in FIG. 4 is a developer supplied from the supply roller 13 to the developing roller 11 at the catch electrode 22. The developer D2 is a developer on the surface of the photoconductor 1 supplied from the developing roller 11 at the position of the main pole 25. The developer D3 is a developer that remains on the outer peripheral surface of the developing roller 11 after being supplied to the photoconductor 1 at the main electrode 25.

The developer D1 is in a state of being agitated and mixed by the rotation of the supply roller 13 and the agitating and conveying member 14, and has a high toner concentration. Toner is printed on the photoconductor 1 at the position of the main pole 25, and the toner in the developer D1 is moved to the photoconductor 1. Therefore, the toner concentration of the developer D3 existing on the downstream side of the position of the main pole 25 in the rotation direction of the developing sleeve 21 is relatively low. The developer D3 has a lower toner concentration in the developer than the developer D1. In the developing agent D3, the concentration of carriers, which are magnetic materials, is high.

As described above, the developer is peeled from the developing sleeve 21 at the position of the peeling electrode 26. The developer that peels from the developing sleeve 21 at the position of the peeling electrode 26 is the developer D3 having a reduced toner concentration. The developer D3 peeled from the developing sleeve 21 moves around the supply roller 13 along the arrow AR0 in FIG. 4 by the rotation of the supply roller 13. The developer D3 having a reduced toner concentration is agitated and mixed with the developer in the housing 15 by the supply roller 13. As a result, the toner concentration of the developer D3 is increased. The developer whose toner concentration has been restored adheres to the developing roller 11 again at the catch electrode 22 of the developing roller 11.

(Magnetic brush 70)
FIG. 5 is a schematic view showing the magnetic brush 70. As described above, the developer containing the toner and the carrier is attracted by the magnetic force of the catch electrode 22 and is held on the outer peripheral surface 21B of the developing sleeve 21. The developing agent is conveyed in the clockwise direction in the drawing by the rotation of the developing sleeve 21. When the developer passes through the gap between the developing roller 11 and the regulating member 12, the regulating member 12 regulates the amount of the developer to be conveyed to a constant level. As schematically shown in FIG. 5, the developer held on the outer peripheral surface 21B of the developing sleeve 21, particularly the carrier, which is a magnetic material, forms spikes along the magnetic field lines 71 formed by the magnetic poles of the magnet roller 20. doing. The magnetic brush 70 is formed by the spikes.

(System configuration of developing device 5)
FIG. 6 is a block diagram showing an outline of the system configuration of the developing apparatus 5. As shown in FIG. 6, the developing device 5 has a developing device control unit 30 that controls the operation of the developing device 5. The developing device control unit 30 includes a timer 31 and a memory 39. The developing device control unit 30 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown).

The developing device control unit 30 includes a developing sleeve driving unit 32, a magnet roller driving unit 33, a supply roller driving unit 34, a stirring and transporting member driving unit 35, a magnetic pole moving unit 38, a developing sleeve angle sensor 36, and the like. The magnet roller angle sensor 37 is connected.

The developing sleeve drive unit 32 is connected to the developing sleeve 21 and rotates or stops the developing sleeve 21. The magnet roller drive unit 33 is connected to the magnet roller 20 and rotates or stops the magnet roller 20. The supply roller drive unit 34 is connected to the supply roller 13 to rotate or stop the supply roller 13. The stirring and transporting member driving unit 35 is connected to the stirring and transporting member 14, and rotates or stops the stirring and transporting member 14. The magnetic pole moving portion 38 changes the arrangement of the plurality of magnetic poles of the magnet roller 20 in the magnet roller 20.

The developing sleeve angle sensor 36 detects the rotation angle of the developing sleeve 21. The magnet roller angle sensor 37 detects the rotation angle of the magnet roller 20. The developing sleeve angle sensor 36 and the magnet roller angle sensor 37 may be, for example, a rotary encoder.

The developing device control unit 30 is also electrically connected to the main controller 130 that controls the entire image forming device 100. The developing device control unit 30 may form a part of the main controller 130.

(Adhesion of developer to regulatory member 12)
Next, a phenomenon in which the developing agent adheres to the regulating member 12 over time with the use of the developing apparatus 5 will be described. FIG. 7 is a schematic view showing a regulating member 12 at the start of use of the developing device 5. As shown in FIG. 7, at the start of use of the developing apparatus 5, a gap having a length Db is formed between the outer peripheral surface of the developing roller 11 (the outer peripheral surface 21B of the developing sleeve 21) and the regulating member 12. ing. The gap between the outer peripheral surface of the developing roller 11 and the regulating member 12 is referred to as a regulating gap.

FIG. 7 shows a virtual circle V centered on the rotation center of the developing roller 11 with a broken line, passing through the tip of the regulating member 12 on the most upstream side of the rotating direction R3 of the developing roller 11 during normal image formation. ing.

The magnetic brush 70 shown in FIG. 5 is conveyed in the rotation direction R3 as the developing sleeve 21 rotates. When the magnetic brush 70 collides with the regulating member 12, the height of the magnetic brush 70 rising from the outer peripheral surface 21B of the developing sleeve 21 is regulated. The tip of the magnetic brush 70 moves to the downstream side in the rotation direction R3 along the virtual circle V shown in FIG. 7.

FIG. 8 is a schematic view showing the adhesion of the developer to the tip of the regulating member 12. Since the height of the magnetic brush 70 is regulated by the regulating member 12, the magnetic brush 70 does not pass through the region outside the virtual circle V on the downstream side in the rotation direction R3. As a result, as shown in FIG. 8, the adhesive developer 91 is present in the range of the tip of the regulating member 12 on the downstream side in the rotation direction R3. First, the toner externalizing agent adheres to the regulating member 12, and then the toner and the carrier adhere to the layer of the externalizing agent, so that the adhesive developing agent 91 adheres to the regulating member 12, and the developing agent aggregates. To do.

FIG. 9 is a schematic view showing the regulation member 12 after aging. As shown in FIG. 9, on the most upstream side of the regulating member 12 in the rotation direction R3, the regulating gap having a length Db is maintained even after a lapse of time. On the other hand, on the downstream side of the regulating member 12 in the rotation direction R3, the regulating gap is narrowed by adding a developer to the tip of the regulating member 12, and a regulating gap having a length Db1 smaller than the length Db is formed. To. When the regulation gap is reduced in this way, the amount of the developer conveyed by the developing roller 11 is reduced.

Further, as shown in FIG. 9, the toner stain 99 also adheres to the surface on the downstream side of the regulating member 12 in the rotation direction R3. Toner scattering occurs when the developer passes through the regulating member 12 and when the toner is developed on the photoconductor 1. When the scattered toner adheres to the surface of the regulating member 12 on the downstream side, toner stain 99 is generated. If the toner stain 99 falls off from the regulating member 12 and adheres to the developing roller 11, it causes image unevenness.

(Cleaning of regulatory member 12)
The developing apparatus 5 of the embodiment provides various means for appropriately removing the adhering developer 91 and the toner stain 99 from the surface of the regulating member 12 during non-image forming of the image forming apparatus 100.

FIG. 10 is a flowchart illustrating conditions for executing the cleaning process of the regulating member 12. As shown in FIG. 10, first, in step S100, it is determined whether or not the cumulative number of prints of the image forming apparatus 100 has reached a predetermined number. The developing device control unit 30 shown in FIG. 6 receives a signal indicating the current cumulative number of prints from the main controller 130 of the image forming device 100, and compares the signal with the threshold value of the cumulative number of prints stored in the memory 39.

When it is determined that the cumulative number of printed sheets has not reached the predetermined number (NO in step S100), then in step S200, the number of printed sheets of the image forming apparatus 100 from the previous cleaning process of the regulating member 12 reaches the predetermined number of sheets. Determine if you did. The developing device control unit 30 shown in FIG. 6 receives a signal indicating the number of printed sheets after the previous cleaning process from the main controller 130 of the image forming device 100, and compares the signal with the threshold value of the number of printed sheets stored in the memory 39.

It is determined that the cumulative number of prints of the image forming apparatus 100 has reached the predetermined number (YES in step S100), or that the number of prints of the image forming apparatus 100 from the previous cleaning process has reached the predetermined number. In the case (YES in step S200), the process proceeds to step S300, and the cleaning process of the regulating member 12 is executed.

If the cumulative number of prints of the image forming apparatus 100 has not reached the predetermined number (NO in step S100) and the number of prints from the previous cleaning process has not reached the predetermined number (NO in step S200), the regulating member The cleaning process of No. 12 is not executed, and the process is terminated as it is (end).

FIG. 11 is a first diagram illustrating cleaning of the regulating member 12 according to the first embodiment. As described above, at the position of the main pole 25, of the toner and the carrier contained in the developer, only the toner adheres to the photoconductor 1. The developer D3 has a lower toner concentration in the developer than the developer D1. In the first embodiment, at the time of non-image formation of the image forming apparatus 100, as shown by the arrow AR1 in FIG. 11, after the developer having a reduced toner concentration is peeled from the developing roller 11 at the position of the peeling electrode 26. By supplying the toner to the developing roller 11 again, the toner concentration in the developing agent around the developing roller 11 is lowered.

FIG. 12 is a second diagram illustrating cleaning of the regulating member 12 according to the first embodiment. While the developer whose toner concentration has decreased is re-caught by the catch electrode 22, the rotation of the developing roller 11 in the rotation direction R3 is continued, and the rotation of the photoconductor 1 in the rotation direction R1 is continued. The toner continues to move from the developing roller 11 to the photoconductor 1 at the position of the main pole 25, and the toner concentration in the developing agent around the developing roller 11 further decreases by continuing to catch the developer whose toner concentration has decreased. To do.

As a result, the toner concentration in the developer conveyed at the position facing the regulating member 12 is reduced. In a developer having a reduced toner concentration, the carrier concentration in the developer is higher than that at the time of normal image formation. Since the density of carriers, which are magnetic materials, is higher than that at the time of normal image formation, the magnetism of the developer is increased. As a result, the magnetization of the magnetic brush 70 formed at the position facing the regulating member 12 is increased, and the height at which the magnetic brush 70 rises from the outer peripheral surface of the developing roller 11 is increased more than usual. Further, by improving the bonding force between the carriers, a harder magnetic brush 70 is formed.

Therefore, the magnetic brush 70 can efficiently scrape off the adhesive developer 91 adhering to the tip of the regulating member 12, and also remove the toner stain 99 adhering to the surface on the downstream side of the regulating member 12. Can be done. Since the developer can be more reliably removed from the surface of the regulating member 12 during non-image formation of the image forming apparatus 100, it is possible to suppress the adhesion of the developer to the surface of the regulating member 12 even after a lapse of time. ..

By periodically executing the cleaning process of the regulating member 12, the narrowing of the regulating gap described with reference to FIG. 9 can be suppressed, so that the decrease in the amount of the developer conveyed by the developing roller 11 can be suppressed. Therefore, it is possible to suppress the deterioration of the image quality due to the decrease in the amount of the developer conveyed.

The first means for re-catching the developer peeled from the developing roller 11 will be described. FIG. 13 is a flowchart showing a first means of catching the developer again.

With reference to FIG. 13, in step S311 it is determined whether or not the image forming apparatus 100 is at the time of image formation. If it is determined that it is not at the time of image formation (NO in step S311), then the peeling electrode 26 is moved in step S312. The developing device control unit 30 shown in FIG. 6 transmits a control signal for moving the peeling electrode 26 to the magnetic pole moving unit 38. The magnetic pole moving unit 38 that has received the control signal moves the peeling electrode 26.

FIG. 14 is a schematic view showing the movement of the peeling electrode 26 in the magnet roller 20. FIG. 14 shows the arrangement of the magnetic poles in the developing roller 11 when the image forming apparatus 100 is not forming an image. FIG. 14 is a broken line showing the position of the peeling electrode 26 during normal image formation. At the time of non-image formation of the image forming apparatus 100, as shown in FIG. 14, the peeling electrode 26 is rotationally moved to the catch electrode 22 side. The peeling pole 26 is brought closer to the catch pole 22, and the distance between the peeling pole 26 and the catch pole 22 is reduced.

Next, in step S313, the developing sleeve 21 is rotated. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the developing sleeve 21 to the developing sleeve driving unit 32. Upon receiving the control signal, the developing sleeve driving unit 32 rotates the developing sleeve 21 in the rotation direction R3. With the rotation of the developing sleeve 21 in the rotation direction R3, printing of toner on the photoconductor 1 is started.

Since the peeling electrode 26 is close to the catching electrode 22, the position where the developer is peeled from the developing roller 11 is moved to the downstream side in the rotation direction R3. As a result, the developer peeled from the developing roller 11 at the position of the peeling electrode 26 is easily caught again by the catching electrode 22. Therefore, the developer whose toner concentration has decreased can be efficiently re-caught, and the toner concentration during development around the developing roller 11 can be rapidly reduced.

Subsequently, in step S314, it is determined whether or not the predetermined time has elapsed. If the predetermined time has not elapsed (NO in step S314), the determination in step S324 is repeated. As a result, the rotation of the developing sleeve 21 is maintained for a predetermined time, and the cleaning process of the regulating member 12 is continued.

When the predetermined time elapses (YES in step S314), the rotation of the developing sleeve 21 is stopped in step S315. The developing device control unit 30 shown in FIG. 6 transmits a control signal for stopping the developing sleeve 21 to the developing sleeve driving unit 32. The developing sleeve 21 that has received the control signal stops rotating. As a result, the printing of the toner on the photoconductor 1 is completed.

Next, in step S316, the peeling electrode 26 is moved to the original position. The developing device control unit 30 shown in FIG. 6 transmits a control signal for moving the peeling electrode 26 to the magnetic pole moving unit 38. The magnetic pole moving unit 38 that has received the control signal moves the peeling pole 26 to the position indicated by the broken line in FIG. Then, the cleaning process is completed (end).

If it is determined in the determination of step S311 that the image is being formed by the image forming apparatus 100 (YES in step S311), the cleaning process is not executed and the process ends as it is (end).

A second means for re-catching the developer peeled from the developing roller 11 will be described. FIG. 15 is a schematic view showing a developer in the housing 15 at the time of normal image formation.

FIG. 15 shows the liquid level S of the developer in the housing 15 during normal image formation. At the time of normal image formation, the developer is stirred and mixed by rotating the supply roller 13, and the developer whose toner concentration is restored is supplied to the developing roller 11. The arrow AR2 shown in FIG. 12 indicates the movement path of the developer peeling from the peeling electrode 26.

FIG. 16 is a flowchart showing a second means of catching the developer again. With reference to FIG. 16, in step S321, it is determined whether or not the image forming apparatus 100 is at the time of image formation. If it is determined that it is not the time of image formation (NO in step S321), then in step S322, the rotation of the supply roller 13 is stopped. The developing device control unit 30 shown in FIG. 6 transmits a control signal for stopping the supply roller 13 to the supply roller drive unit 34. The supply roller drive unit 34 that has received the control signal stops the supply roller 13.

At the time of non-image formation of the image forming apparatus 100, the rotation of the supply roller 13 is stopped. When the rotation of the supply roller 13 is stopped, the supply roller 13 does not agitate the developer, so that the developer peeled from the developing roller 11 collects around the supply roller 13. FIG. 17 is a schematic view showing a developer in the housing 15 when the supply roller 13 is stopped. The developer D4 shown in FIG. 17 indicates a developer having a low toner concentration accumulated around the supply roller 13. The developer D4 exists closer to the developing roller 11 than the liquid level S shown in FIG. The developer D4 exists at a position closer to the catch electrode 22 than the liquid level S at the time of normal image formation.

As a result, the developer D4 is likely to be re-caught at the catch electrode 22. The arrow AR3 shown in FIG. 17 indicates the movement path of the developer D4 attracted to the catch electrode 22. In this way, the developer whose toner concentration has decreased can be efficiently re-caught, and the toner concentration during development around the developing roller 11 can be rapidly reduced.

Returning to FIG. 16, the developing sleeve 21 is then rotated in step S323. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the developing sleeve 21 to the developing sleeve driving unit 32. Upon receiving the control signal, the developing sleeve driving unit 32 rotates the developing sleeve 21 in the rotation direction R3. With the rotation of the developing sleeve 21 in the rotation direction R3, printing of toner on the photoconductor 1 is started.

Subsequently, in step S324, it is determined whether or not the predetermined time has elapsed. If the predetermined time has not elapsed (NO in step S324), the determination in step S324 is repeated. As a result, the rotation of the developing sleeve 21 is maintained for a predetermined time, and the cleaning process of the regulating member 12 is continued.

When the predetermined time elapses (YES in step S324), the rotation of the developing sleeve 21 is stopped in step S325. The developing device control unit 30 shown in FIG. 6 transmits a control signal for stopping the developing sleeve 21 to the developing sleeve driving unit 32. The developing sleeve 21 that has received the control signal stops rotating. As a result, the printing of the toner on the photoconductor 1 is completed. Then, the cleaning process is completed (end).

If it is determined in the determination of step S321 that the image is being formed by the image forming apparatus 100 (YES in step S321), the cleaning process is not executed and the process ends as it is (end).

Toner is printed on the photoconductor 1 by the rotation of the developing sleeve 21 in the rotation direction R3 in step S313 shown in FIG. 13 and the rotation of the developing sleeve 21 in the rotation direction R3 in step S323 shown in FIG. At this time, it is desirable to print the toner on the photoconductor 1 at a higher density than when the image forming apparatus 100 normally forms an image. By printing a high-concentration toner on the photoconductor 1, the toner concentration of the developer around the developing roller 11 can be lowered in a short time, so that the effect of scraping the dirt on the regulating member 12 by the magnetic brush 70 is increased. Therefore, the time required for the cleaning process of the regulating member 12 can be shortened.

The electrostatic latent image formed on the photoconductor 1 may be a solid image so that the toner adhering to the developing roller 11 moves 100% toward the photoconductor 1 when the cleaning process is executed. A method of adjusting the amount of charge of the toner in order to facilitate the movement of the toner from the developing roller 11 to the photoconductor 1, a method of adjusting the strength of the electric field applied to the developing roller 11 to hold the toner, and a writing device 4 Appropriate control may be performed, such as a method of adjusting the high intensity when exposing the photoconductor 1.

(Embodiment 2)
FIG. 18 is a flowchart illustrating cleaning of the regulating member 12 according to the second embodiment.

With reference to FIG. 18, in step S331, it is determined whether or not the image forming apparatus 100 is at the time of image formation. If it is determined that it is not the time of image formation (NO in step S331), then in step S332, the developing sleeve 21 is rotated forward. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the developing sleeve 21 to the developing sleeve driving unit 32. Upon receiving the control signal, the developing sleeve driving unit 32 rotates the developing sleeve 21 in the rotation direction R3. With the rotation of the developing sleeve 21 in the rotation direction R3, printing of toner on the photoconductor 1 is started.

FIG. 19 is a schematic view showing a decrease in the toner concentration of the developer on the outer peripheral surface of the developing roller. By rotating the developing sleeve 21 in the forward direction and developing the toner at the position of the main pole 25, as described above, development of the region downstream from the main pole 25 in the rotation direction R3 from the main pole 25 to the peeling pole 26 is developed. The toner concentration of agent D3 decreases.

Next, in step S333, the developing sleeve 21 is rotated in the reverse direction. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the developing sleeve 21 to the developing sleeve driving unit 32. Upon receiving the control signal, the developing sleeve driving unit 32 rotates the developing sleeve 21 in the reverse rotation direction R3r. When the rotation of the developing sleeve 21 in the rotation direction R3 is stopped, the printing of the toner on the photoconductor 1 is completed.

Subsequently, in step S334, the developing sleeve 21 is stopped. The developing device control unit 30 shown in FIG. 6 receives a signal indicating the rotation angle of the developing sleeve 21 from the developing sleeve angle sensor 36. Upon receiving the signal indicating that the developing sleeve 21 has rotated in the reverse rotation direction R3r by a predetermined angle, the developing device control unit 30 transmits a control signal for stopping the developing sleeve 21 to the developing sleeve driving unit 32. The developing sleeve driving unit 32 that has received the control signal stops the developing sleeve 21.

FIG. 20 is a schematic view of a state in which a developer having a reduced toner concentration faces the regulating member 12. From the state shown in FIG. 19 in which the toner concentration in the developer is reduced in a part around the developing roller 11, the reverse rotation direction R3r (counterclockwise in the drawing) is opposite to the rotation direction R3 (clockwise in the drawing). The developing roller 11 is rotated in the direction). The developer whose toner concentration has decreased due to development on the photoconductor 1 is conveyed to a position facing the regulating member 12 as the developing roller 11 rotates in the reverse direction.

As a result, the toner concentration in the developer passing through the position facing the regulating member 12 is reduced. In a developer having a reduced toner concentration, the carrier concentration in the developer is higher than that at the time of normal image formation. As the concentration of the carrier, which is a magnetic material, becomes higher than usual, the magnetism of the developer becomes higher, so that the magnetic brush 70 formed at a position facing the regulating member 12 can be seen from the outer peripheral surface of the developing roller 11. The height to stand up is higher than usual. Therefore, the magnetic brush 70 can scrape off the adhesive developer 91 adhering to the tip of the regulating member 12.

Since the developing roller 11 rotates in the direction opposite to that at the time of image formation, the increased magnetic brush 70 is surely brought into contact with the toner stain 99 adhering to the regulating member 12. Therefore, the toner stain 99 generated on the downstream surface of the regulating member 12 can be easily removed.

In this way, the developer can be more reliably removed from the surface of the regulating member 12 during non-image formation of the image forming apparatus 100, so that the developing agent adheres to the surface of the regulating member 12 even after a lapse of time. It can be suppressed.

In this way, the cleaning process of the regulating member 12 is executed, and the process is completed (end).

If it is determined in the determination of step S331 that the image is being formed by the image forming apparatus 100 (YES in step S331), the cleaning process is not executed and the process ends as it is (end).

(Embodiment 3)
FIG. 21 is a flowchart illustrating cleaning of the regulating member 12 according to the third embodiment.

With reference to FIG. 21, in step S341, it is determined whether or not the image forming apparatus 100 is at the time of image formation. If it is determined that it is not the time of image formation (NO in step S341), then the magnet roller 20 is rotated in step S342. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the magnet roller 20 to the magnet roller drive unit 33. The magnet roller drive unit 33 that has received the control signal rotates the magnet roller 20 by a predetermined angle. The developing device control unit 30 receives a signal indicating the rotation angle of the magnet roller 20 from the magnet roller angle sensor 37.

FIG. 22 is a schematic view showing the rotation of the magnet roller 20. FIG. 22 shows the arrangement of the magnetic poles in the developing roller 11 when the image forming apparatus 100 is not forming an image.

In the arrangement shown in FIG. 3 at the time of normal image formation, the regulation pole 24 is arranged at a position facing the regulation member 12 among the plurality of magnetic poles of the magnet roller 20. On the other hand, during non-image formation of the image forming apparatus 100, the main pole 25 is moved to a position facing the regulating member 12 by rotating the magnet roller 20 in the counterclockwise direction in the drawing by a predetermined angle.

After moving the main pole 25 having a magnetic flux density higher than that of the regulating pole 24 to a position facing the regulating member 12, the developing sleeve 21 is rotationally driven in step S343. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the developing sleeve 21 to the developing sleeve driving unit 32. The developing sleeve drive unit 32 that has received the control signal rotates the developing sleeve 21.

Since the main pole 25 has a higher magnetic flux density than the regulating pole 24, the magnetization of the magnetic brush 70 formed at a position facing the regulating member 12 increases, and the height at which the magnetic brush 70 rises from the outer peripheral surface of the developing roller 11 increases. It is more than usual. By rotating the developing sleeve 21 in this state, the magnetic brush 70 can scrape off the adhesive developing agent 91 adhering to the tip of the regulating member 12.

The direction in which the developing sleeve 21 rotates at this time is not the rotation direction R3 but the reverse rotation direction R3r. Since the peeling electrode 26 is moved to the upstream side of the rotation direction R3 as compared with the normal image forming, the developer peeled from the developing roller 11 may not fit in the developing device 5 depending on the shape of the developing device 5, and the image is formed. There is a risk that the inside of the apparatus 100 will be soiled with a developer. By rotating the developing sleeve 21 in the rotation direction R3, it is possible to suppress the scattering of the developing agent into the machine of the image forming apparatus 100.

Subsequently, in step S344, it is determined whether or not the predetermined time has elapsed. If the predetermined time has not elapsed (NO in step S344), the determination in step S344 is repeated. As a result, the rotation of the developing sleeve 21 is maintained for a predetermined time, and the cleaning process of the regulating member 12 is continued. When the predetermined time elapses (YES in step S344), the developing sleeve 21 is stopped in step S345. The developing device control unit 30 shown in FIG. 6 transmits a control signal for stopping the developing sleeve 21 to the developing sleeve driving unit 32. The developing sleeve 21 that has received the control signal stops rotating.

Then, in step S346, the magnet roller 20 is rotated to the original position. The developing device control unit 30 shown in FIG. 6 transmits a control signal for rotating the magnet roller 20 to the magnet roller drive unit 33. The magnet roller drive unit 33 that has received the control signal rotates the magnet roller 20 by a predetermined angle. Then, the cleaning process is completed (end).

If it is determined in the determination of step S341 that the image is being formed by the image forming apparatus 100 (YES in step S341), the cleaning process is not executed and the process ends as it is (end).

Hereinafter, examples will be described. An image forming apparatus (full-color multifunction device bizhub C368) manufactured by Konica Minolta Co., Ltd. was used to form an image under the conditions of a temperature of 23 ° C. and a humidity of 65%, and the durability transition of the amount of the developer conveyed on the developing roller was measured.

In the first embodiment, as described in the first embodiment, the cleaning process of the regulating member 12 was executed by lowering the toner concentration in the developer around the developing roller 11. During non-image formation of the image forming apparatus 100, a solid patch was continuously printed for 30 seconds on the entire width of the developing roller 11. Then, the developing sleeve 21 was continuously rotated in the rotation direction R3 for 10 minutes. The rotation speed of the developing sleeve 21 at this time was set to the maximum speed at which the developing sleeve 21 can rotate. The cleaning process was performed every 100,000 sheets were printed.

In the second embodiment, as described in the second embodiment, the cleaning process of the regulating member 12 is executed by rotating the developing roller 11 in the reverse direction. At the time of non-image formation of the image forming apparatus 100, a solid patch was printed on the entire width of the developing roller 11 for a length of one quarter of the developing roller 11. After that, the developing roller 11 was rotated in the reverse rotation direction R3r for one round of the developing roller 11. The rotation speed of the developing sleeve 21 at this time was set to the maximum speed at which the developing sleeve 21 can rotate. The cleaning process was performed every time 500 sheets were printed. In the second embodiment, since the force for scraping the dirt of the regulating member 12 is smaller than that in the first embodiment, the cleaning process is performed frequently.

In the third embodiment, as described in the third embodiment, the magnet roller 20 is rotated to change the arrangement of the magnetic poles, thereby performing the cleaning process of the regulating member 12. At the time of non-image formation of the image forming apparatus 100, the magnet roller 20 was rotated to change the arrangement of the magnetic poles, and then the developing sleeve 21 was rotated in the reverse rotation direction R3r for 10 seconds. The rotation speed of the developing sleeve 21 at this time was set to the maximum speed at which the developing sleeve 21 can rotate. The cleaning process was performed every 1000 sheets were printed. In the third embodiment, since the force for scraping the dirt of the regulating member 12 is smaller than that of the first embodiment and larger than that of the second embodiment, the frequency of performing the cleaning process is also the frequency between the first and second embodiments. did.

In the comparative example, the image formation was continued without executing the cleaning process of the regulating member 12.

FIG. 23 is a graph showing changes in the amount of developer conveyed with respect to the number of printed sheets in Examples and Comparative Examples. The horizontal axis of FIG. 23 indicates the number of prints. The vertical axis of FIG. 23 shows the amount of the developer conveyed on the developing roller.

In the comparative example, when the number of printed sheets shown in FIG. 23 was in the range of N1, the external additive in the developing agent adhered to the downstream side of the tip of the regulating member 12 in the rotational direction. In the range where the number of printed sheets was N2, toner and carriers adhered on the external additive. Due to this adhesion, the size of the gap between the outer peripheral surface of the developing roller 11 and the regulating member 12 is reduced, and as a result, the amount of the developing agent conveyed is reduced as shown in FIG. 23. When the number of printed sheets was in the range of N3, the adhesion of toner and carriers was saturated, and as a result, as shown in FIG. 23, the decrease in the amount of the developer conveyed was small.

As shown in FIG. 23, as compared with the comparative examples, in each of the examples, it was possible to suppress a decrease in the amount of the developer transported after the durability. Further, in any of the examples, image unevenness due to the removal of the toner stain 99 from the downstream surface of the regulating member 12 did not occur during the durability transition measurement of the developer transport amount.

From the above, in the developing apparatus 5 according to the embodiment, even if the developing agent adheres to the surface of the regulating member 12, the adhering developer can be removed from the surface of the regulating member 12 by executing the cleaning process. As a result, it was shown that the decrease in the amount of the developer conveyed can be suppressed through the durability.

It should be considered that the embodiments and examples disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Photoreceptor, 2 Cleaning device, 3 Charging device, 4 Writing device, 5 Developing device, 6 Recording material, 11 Developing roller, 12 Regulatoring member, 13 Supply roller, 14 Stirring and transporting member, 15 Housing, 20 Magnet roller, 20A, 21B outer peripheral surface, 21 developing sleeve, 21A inner peripheral surface, 22 catching pole, 23 conveying pole, 24 regulating pole, 25 main pole, 26 peeling pole, 70 magnetic brush, 71 magnetic field line, 91 adhesive developer, 99 toner stain, 100 Image forming apparatus, D1, D2, D3, D4 developer, DR1 transport direction, R1, R2, R3 rotation direction, R3r reverse rotation direction.

Claims (16)

A developing device provided in an image forming device that forms an image using a developing agent.
A cylindrical developing sleeve and a developing roller having a plurality of magnetic poles arranged along the inner peripheral surface of the developing sleeve.
A regulatory member that regulates the thickness of the developer on the outer peripheral surface of the developing sleeve, and
A control unit that controls the operation of the developing apparatus is provided.
A magnetic brush is formed on the outer peripheral surface of the developing sleeve by the developer.
The control unit rotates the developing sleeve in a state where the magnetization of the magnetic brush formed at a position facing the regulating member is higher than that at the time of image formation of the image forming apparatus when the image forming apparatus is not formed. run the cleaning process to be,
The developer contains toner and carriers.
The control unit lowers the toner concentration of the developer passing through a position facing the restricting member when the image forming apparatus is not forming an image.
The image forming apparatus includes a photoconductor and includes a photoconductor.
At the time of non-image formation of the image forming apparatus, the control unit prints the toner on the photoconductor, peels off the developer having a reduced toner concentration from the developing roller, and then supplies the toner to the developing roller again. ,
The plurality of magnetic poles have a catch electrode for holding the developer in the developing sleeve and a release electrode for peeling the developer from the developing sleeve.
The control unit is a developing device that moves the peeling electrode to bring it closer to the catch electrode when the image forming apparatus is not forming an image . Before SL control unit during non-image formation of said image forming apparatus, printing the toner concentration higher than during image formation of said image forming apparatus to the photosensitive body, a developing device according to claim 1. A developing device provided in an image forming device that forms an image using a developing agent.
A cylindrical developing sleeve and a developing roller having a plurality of magnetic poles arranged along the inner peripheral surface of the developing sleeve.
A regulatory member that regulates the thickness of the developer on the outer peripheral surface of the developing sleeve, and
A control unit that controls the operation of the developing apparatus is provided.
A magnetic brush is formed on the outer peripheral surface of the developing sleeve by the developer.
The control unit rotates the developing sleeve in a state where the magnetization of the magnetic brush formed at a position facing the regulating member is higher than that at the time of image formation of the image forming apparatus when the image forming apparatus is not formed. Perform a cleaning process to let
The developer contains toner and carriers.
The control unit lowers the toner concentration of the developer passing through a position facing the restricting member when the image forming apparatus is not forming an image.
The image forming apparatus includes a photoconductor and includes a photoconductor.
Wherein, during non-image formation of said image forming apparatus, wherein the developing sleeve is rotated to print the toner to the photosensitive body, thereby subsequently rotating the developing sleeve in the opposite direction, the current image device. The developing apparatus according to claim 3, wherein the control unit prints the toner on the photoconductor at a higher density than when the image forming apparatus forms an image, when the image forming apparatus does not form an image. A developing device provided in an image forming device that forms an image using a developing agent.
A cylindrical developing sleeve and a developing roller having a plurality of magnetic poles arranged along the inner peripheral surface of the developing sleeve.
A regulatory member that regulates the thickness of the developer on the outer peripheral surface of the developing sleeve, and
A control unit that controls the operation of the developing apparatus is provided.
A magnetic brush is formed on the outer peripheral surface of the developing sleeve by the developer.
The control unit rotates the developing sleeve in a state where the magnetization of the magnetic brush formed at a position facing the regulating member is higher than that at the time of image formation of the image forming apparatus when the image forming apparatus is not formed. Perform a cleaning process to let
The developing roller further has a magnet roller rotatably provided with respect to the inner peripheral surface of the developing sleeve, and the plurality of magnetic poles are arranged side by side in the circumferential direction of the magnet roller.
The plurality of magnetic poles have a regulating pole arranged at a position facing the regulating member at the time of image formation of the image forming apparatus, and another magnetic pole having a magnetic flux density higher than that of the regulating pole.
Wherein, during non-image formation of said image forming apparatus, for moving the other pole at a position facing the regulating member, the current image device. The image forming apparatus includes a photoconductor and includes a photoconductor.
The developing apparatus according to claim 5 , wherein the other magnetic pole is a main pole arranged at a position facing the photoconductor at the time of image formation of the image forming apparatus. Wherein the control unit after moving the other pole at a position facing the regulating member, wherein the developing sleeve, the rotation direction at the time of image formation of said image forming apparatus is rotated in the reverse direction, according to claim 5 or 6 The developing apparatus according to. Any of claims 1 to 7 , wherein the control unit executes the cleaning process when the cumulative number of prints by the developing device or the number of prints since the previous execution of the cleaning process reaches a predetermined number. The developing apparatus according to item 1. Photoreceptor and
An image forming apparatus including the developing apparatus according to any one of claims 1 to 8 . It is a control method of a developing device provided in an image forming device that forms an image using a developing agent.
The developing device
A cylindrical developing sleeve and a developing roller having a plurality of magnetic poles arranged along the inner peripheral surface of the developing sleeve.
A regulating member for regulating the thickness of the developing agent on the outer peripheral surface of the developing sleeve is provided.
A magnetic brush is formed on the outer peripheral surface of the developing sleeve by the developer.
A step of determining whether or not it is time to form an image of the image forming apparatus,
When it is determined that the image forming apparatus is not forming an image in the determination step, the magnetization of the magnetic brush formed at a position facing the regulating member is higher than that at the time of forming an image of the image forming apparatus. With a step of performing a cleaning process of rotating the developing sleeve in
The developer contains toner and carriers.
The step of performing the cleaning process includes a step of lowering the toner concentration of the developer passing through a position facing the regulating member.
The image forming apparatus includes a photoconductor and includes a photoconductor.
The step of executing the cleaning process is
The step of printing the toner on the photoconductor and
A step of peeling the developer having a reduced toner concentration from the developing roller,
Including the step of resupplying the developer peeled from the developing roller to the developing roller in the peeling step.
The plurality of magnetic poles have a catch electrode for holding the developer in the developing sleeve and a release electrode for peeling the developer from the developing sleeve.
A method of controlling a developing apparatus , wherein the step of executing the cleaning process includes a step of moving the peeling electrode to bring it closer to the catch electrode . Performing a pre-Symbol cleaning process than during image formation of said image forming apparatus comprising the step of printing the toner on the photosensitive member in a high concentration, the control method of the developing device according to claim 10. It is a control method of a developing device provided in an image forming device that forms an image using a developing agent.
The developing device
A cylindrical developing sleeve and a developing roller having a plurality of magnetic poles arranged along the inner peripheral surface of the developing sleeve.
A regulating member for regulating the thickness of the developing agent on the outer peripheral surface of the developing sleeve is provided.
A magnetic brush is formed on the outer peripheral surface of the developing sleeve by the developer.
A step of determining whether or not it is time to form an image of the image forming apparatus,
When it is determined that the image forming apparatus is not forming an image in the determination step, the magnetization of the magnetic brush formed at a position facing the regulating member is higher than that at the time of forming an image of the image forming apparatus. With a step of performing a cleaning process of rotating the developing sleeve in
The developer contains toner and carriers.
The step of performing the cleaning process includes a step of lowering the toner concentration of the developer passing through a position facing the regulating member.
The image forming apparatus includes a photoconductor and includes a photoconductor.
The step of executing the cleaning process is
A step of rotating the developing sleeve to print the toner on the photoconductor,
After the step of the printing, and a step of rotating the developing sleeve in the reverse direction, the control method of the current image device. It is a control method of a developing device provided in an image forming device that forms an image using a developing agent.
The developing device
A cylindrical developing sleeve and a developing roller having a plurality of magnetic poles arranged along the inner peripheral surface of the developing sleeve.
A regulating member for regulating the thickness of the developing agent on the outer peripheral surface of the developing sleeve is provided.
A magnetic brush is formed on the outer peripheral surface of the developing sleeve by the developer.
A step of determining whether or not it is time to form an image of the image forming apparatus,
When it is determined that the image forming apparatus is not forming an image in the determination step, the magnetization of the magnetic brush formed at a position facing the regulating member is higher than that at the time of forming an image of the image forming apparatus. With a step of performing a cleaning process of rotating the developing sleeve in
The developing roller further has a magnet roller rotatably provided with respect to the inner peripheral surface of the developing sleeve, and the plurality of magnetic poles are arranged side by side in the circumferential direction of the magnet roller.
The plurality of magnetic poles have a regulating pole arranged at a position facing the restricting member at the time of image formation of the image forming apparatus, and another magnetic pole having a magnetic flux density larger than that of the regulating pole.
Executing the cleaning process includes a step of moving the other pole at a position facing the regulating member, the control method of the current image device. The image forming apparatus includes a photoconductor and includes a photoconductor.
The control method for a developing device according to claim 13 , wherein the other magnetic pole is a main pole arranged at a position facing the photoconductor at the time of image formation of the image forming device. The step of executing the cleaning process is
A step of moving the other magnetic pole to a position facing the regulating member, and
The method for controlling a developing device according to claim 13 or 14 , further comprising a step of rotating the developing sleeve in a direction opposite to the direction of rotation of the image forming device at the time of image formation after the moving step. The method according to any one of claims 10 to 15 , wherein when the cumulative number of prints by the developing device or the number of prints since the previous execution of the cleaning process reaches a predetermined number, the cleaning process is executed. How to control the developing device.

Images