JP4210194B2 - Development device - Google Patents

Description

  The present invention relates to a developing device that supplies a developer used for electrophotographic image formation from a developer container to a developing unit via a storage unit, and develops the developing unit.

  In an electrophotographic image forming apparatus using a two-component developer composed of a toner and a carrier, the two-component developer in the developing unit is detected by a magnetic permeability sensor, and when the density decreases, the toner is transferred from the toner cartridge to the developing unit. It is configured to replenish and always maintain a constant toner density. Further, when the toner concentration continues to be lower than a predetermined reference concentration for a predetermined time or more, it is determined that there is no toner in the toner cartridge, the operator is notified that there is no toner in the toner cartridge, and the operation is performed. It is configured to prompt the user to replace the toner cartridge.

  In this configuration, since it is suddenly notified that the toner has run out, it takes time for the operator to prepare for replacing the toner cartridge, and the image forming apparatus cannot be used for a long time. Therefore, in order to be able to predict in advance that the toner in the toner cartridge will run out, it is necessary to be able to detect the remaining amount of toner.

  As a first conventional technique for detecting the remaining amount of toner in the toner cartridge, a magnetic permeability sensor for detecting the magnetic permeability of the developer supplied from the developing unit to the photosensitive drum, and the optical of the photosensitive drum developed by the developing unit There is an image forming apparatus that includes an optical density sensor that detects density. In this image forming apparatus, by using a magnetic permeability sensor and an optical density sensor, which are two different types of sensors, the toner density of the developer supplied from the developing unit to the photosensitive drum, and the optical density of the photosensitive drum. The remaining amount of toner in the toner cartridge is detected based on the density.

  On the other hand, the toner cartridge connected to the image forming apparatus main body is formed in a cylindrical shape with both ends closed, and is provided with a storage space for storing toner. A part of the outer peripheral portion in the axial direction of the toner cartridge is formed with a through hole that penetrates in the radial direction and communicates the storage space with the outer space of the toner cartridge. The toner cartridge is coupled to the image forming apparatus main body so as to face a developing unit provided in the image forming apparatus main body. In this state, the toner cartridge is rotated around the axis, and the toner is supplied to the developing unit through the through hole. As a conventional technique for detecting the remaining amount of such a cylindrical toner cartridge, as a conventional technique, when the total operation time of the supply operation unit that supplies toner from the toner cartridge to the developing unit exceeds a predetermined time, A method of determining that the amount of toner present is small or absent is conceivable. However, the supply amount per unit time of the supply operation unit varies greatly between individual image forming apparatuses, and such a variation causes an error in the determination that the amount of toner remaining in the toner cartridge is small or absent. there is a possibility. As a result, even if a sufficient amount of toner remains in the toner cartridge, it is mistakenly determined that the remaining amount of toner is low or not, or conversely, the toner in the toner cartridge runs out and the image formed on the recording paper becomes thin. In spite of this, there is a possibility of misjudging that sufficient toner remains.

  In order to avoid such a misjudgment as much as possible, as a second conventional technique, the prescribed pattern created on the photosensitive drum is developed and its optical density is detected. There is an image forming apparatus that controls a supply operation unit to operate when it is lower than a reference value. In this image forming apparatus, the larger the difference between the toner density reference value and the detected value, the longer the operation time of the supply operation unit and the more the toner supply amount. This control is handled as a replenishment amount per transfer sheet (see, for example, Patent Document 1).

JP 9-197797 A

  The image forming apparatuses according to the first and second conventional techniques detect the remaining amount of toner in the toner cartridge based on the decrease in the optical density of the photosensitive drum developed by the developing unit. Therefore, since the development is executed in a state where the optical density is lowered, the quality of the development is lowered. Therefore, since the development accuracy is poor, it is not suitable for detecting the remaining amount of toner.

  In the above toner cartridge, toner is supplied from one place in the axial direction of the developing roller. Since the toner is supplied from one place, the toner density can vary in the axial direction of the developing roller. Therefore, the developer is excessively agitated in the developing portion in order to make the toner density uniform. If the developer is agitated excessively, the toner adheres firmly to the surface of the carrier, causing the carrier to deteriorate, the amount of charge of the toner changes, and a density drop or fog occurs on the image that cannot be put to practical use. Becomes worse.

  Further, as described above, the remaining amount detection method for the cylindrical toner cartridge is inaccurate and a new detection method is desired.

  Accordingly, an object of the present invention is to secure a time for a user to replenish the developer in the developing unit without stopping the developing operation of the developing unit after the developer accommodated in the developer container is emptied. It is an object of the present invention to provide a developing device that can perform development with good development accuracy.

The present invention includes a developing unit for developing a latent image with a developer,
A storage portion that has an inner peripheral surface that is convex downward, and that temporarily stores the developer replenished from the developer container in a storage space formed by the inner peripheral surface ;
Replenishment means for replenishing the developer from the developer container to the reservoir;
Supply means for supplying the developer stored in the storage unit to the developing unit;
An agitation means comprising an outer peripheral portion that is rotationally driven around an axis, and agitating the developer stored in the storage portion by the rotational driving of the outer peripheral portion;
It is made of a material that has flexibility, is formed into a film, and has one end connected to the outer peripheral portion and at least one of magnetic and conductive, and is formed on the other end of the holding body. A detection auxiliary member to be held and a magnetic permeability sensor that is provided facing the outer peripheral surface of the storage unit and detects a change in the magnetic field at a predetermined position, and detects the amount of developer stored in the storage unit First detection means;
Second detection means for detecting the amount of developer held in the developing section;
An informing means for informing the information;
The first state in which the retention amount detected by the second detection means is equal to or less than the predetermined first determination amount over the predetermined first determination time, and the storage amount detected by the first detection means over the predetermined second determination time. And a control unit that controls the notification unit so as to notify the determination result when it is determined that the determination is in at least one of the second states that are equal to or less than a predetermined second determination amount. Developing device.

According to the present invention, the first detecting means detects a storage amount of the developer stored in savings engaging portion. The second detection unit detects the amount of developer held in the developing unit. Accordingly, since the holding amount and the storage amount are detected, the developing device can be controlled based on the developer holding amount and the developer storage amount. Moreover, since the stirring means for stirring the developer stored in the storage unit is included, the developer stored temporarily can be stirred. Therefore, the developer can be diffused without any deviation over the entire storage portion. In addition, since the first detection unit is configured to detect the storage amount of the developer in accordance with the rotational driving of the outer peripheral portion of the stirring unit, the developer is diffused evenly over the entire storage unit. At the same time, the storage amount of the developer in the storage portion can be detected.

When it is determined that the control unit is in at least one of the first state and the second state, the control unit controls the notification unit so as to notify the determination result. The first state is a state in which the holding amount detected by the second detection means is equal to or less than a predetermined first determination amount over a predetermined first determination time. The second state is a state in which the storage amount detected by the first detection means is equal to or less than a predetermined second determination amount over a predetermined second determination time. In at least one of the first state and the second state, there is a high possibility that the developer container is empty. Therefore, since the notification means notifies the determination result, the user can recognize that the developer container is empty. Further, it is possible to prevent development of the latent image in a state where the developer is insufficient. This can prevent the quality of development from deteriorating. Therefore, it is possible to always obtain good development accuracy.

  The supply unit supplies the developer temporarily stored in the storage unit to the developing unit. Therefore, even if the developer stored in the developer storage container is replenished to the storage unit and becomes empty, the development unit can develop using the developer stored in the storage unit. Therefore, the user can develop the latent image without replenishing the developer immediately after recognizing that the developer accommodated in the developer container is empty. Can be improved.

The present invention, the stirring means stirs the developer stored in the reservoir section in conjunction with the operation of the supply means,
The control means controls the agitation means so that the developer is agitated for a predetermined time when the agitation means is not operating while the developer is being replenished to the reservoir by the replenishment means.

According to the present invention,撹拌it means is provided to work with the supply means. Therefore, the configuration can be simplified as compared with the case where the supply unit and the stirring unit are provided so as to operate independently. As a result, the manufacturing cost can be reduced.

  The control means controls the agitation means so that the developer is agitated for a predetermined time when the agitation means is not operating while the replenishment means is replenishing the developer to the reservoir. Accordingly, it is possible to reliably prevent the developer from being replenished to the storage portion by the replenishing unit and the developer to be unevenly distributed only in a part to be replenished. The supply of the developer from the developer container to the storage unit can be smoothly performed without delay. In addition, even when the operation of supplying the developer to the developing unit and the operation of the stirring unit stirring the developer are linked, it is ensured that the developer is unevenly distributed only in a part to be replenished. Can be prevented. Moreover, the supply operation of the developer to the developing unit performed at the same time as the stirring can prevent excessive supply by setting the predetermined time to a short time.

Furthermore, the present invention is,
Control means, when the storage amount detected by the first detecting means comprises the following main replenishing amount predetermined to control the replenishing means for replenishing the developer, when the developer is replenished by the replenishing means, a developer The stirring means is controlled so as to stir the water.

According to the present invention, the control means controls the replenishing means for replenishing the developer when the storage amount detected by the first detecting means is equal to or less than the predetermined replenishment amount. Therefore, it is possible to prevent the storage amount from being less than the replenishment amount. Accordingly, the supply of the developer from the storage unit to the development unit is not delayed due to the shortage of the developer in the storage unit. Therefore, the developer can be smoothly supplied from the storage unit to the developing unit.

Or the control means, when the developer is replenished by the replenishing means controls the stirring unit to stir the developer. Accordingly, it is possible to reliably prevent the developer from being replenished to the storage portion by the replenishing unit and the developer to be unevenly distributed only in a part to be replenished. As a result, the developer can be smoothly supplied from the developer container to the storage unit without delay.

  Further, according to the present invention, when the control unit determines that it is in the first state, the control unit controls the developing unit to stop the developing operation of the latent image, and then supplies the developer to supply the developer for a predetermined supply time. When the developing unit is controlled to resume the developing operation when the holding amount increases by this supply operation, and it is determined that the holding amount does not increase even if the supply operation is executed and is not in the second state The notifying means is controlled to notify that it is abnormal.

  According to the present invention, when it is determined that the control unit is in the first state, the control unit controls the developing unit so as to stop the developing operation of the latent image. Thereafter, the control means controls the supply means so as to supply the developer over a predetermined supply time. The control unit controls the developing unit so that the developing operation is resumed when the holding amount is increased by the supplying operation of the supplying unit. This can prevent development in a state where the developer is insufficient. Therefore, it is possible to prevent the development quality from deteriorating.

  Further, the notifying means notifies that there is an abnormality when it is determined that the holding amount does not increase even if the supply operation is executed and is not in the second state. If the retained amount does not increase even when the supply operation is performed even though the developer is present in the storage unit, there is an abnormality in at least one of the development unit and the supply unit. Since this abnormality is notified to the user, the user can recognize that there is an abnormality. Thus, the user can deal with the abnormality as soon as possible.

  Further, according to the present invention, when the control unit determines that the holding state is at least one of the first state and the second state, the holding amount is equal to or greater than the minimum holding amount capable of developing the latent image. The developing unit is controlled to continue the developing operation.

  According to the present invention, even if it is determined that the control unit is in at least one of the first state and the second state, the developing operation is continued when the holding amount is equal to or more than the minimum holding amount. To control the developing section. If the holding amount is equal to or higher than the minimum holding amount, the development quality does not deteriorate. Therefore, even if it is determined that the state is at least one of the first state and the second state, the development quality is not deteriorated even if the development operation is not stopped immediately, and therefore the development operation is executed. This can prevent the user from suddenly becoming unable to use the developing device.

  Further, the present invention is characterized in that the control means controls the developing unit so as to stop the developing operation after the developing operation is completed until the developer is supplied from the developer container.

  According to the present invention, the control means controls the developing unit to stop the developing operation after the developing operation is completed until the developer is supplied from the developer container. As a result, the developing operation can be continued before the developer is replenished to prevent the developer from being insufficient. Therefore, it is possible to prevent the development quality from deteriorating due to the shortage of the developer.

Furthermore, the present invention is a developing device provided in an image forming apparatus capable of forming an image received via a communication line,
After completion of the developing operation, the control means executes the developing operation for the developing operation for forming the image received via the communication line, and the developer is supplied from the developer container for the remaining developing operation. The developing unit is controlled so as to stop the developing operation until it is done.

  According to the present invention, the developing device is provided in an image forming apparatus capable of forming an image received via a communication line. Therefore, the developing device can develop the image received via the communication line. For the developing operation for forming an image received via the communication line after the completion of the developing operation, the developing unit is controlled by the control means so as to execute the developing operation. As for the remaining developing operation, the developing unit is controlled by the control means so as to stop the developing operation until the developer is supplied from the developer container. A transmission source that transmits an image via a communication line cannot recognize the state of the developing device if the transmission source is located away from the received developing device. Therefore, since the developing operation is executed with priority over the remaining developing operations, the image received via the communication line can be developed without degrading the quality. Further, since the developing operation is executed, the image received via the communication line can be confirmed by the user as soon as possible.

Furthermore, the present invention is an image forming apparatus comprising the developing device.
According to the present invention, since the image forming apparatus includes the developing device, the function of the developing device can be achieved.

  According to the present invention, the user can appropriately recognize that the developer container is empty. Accordingly, it is possible to prevent development of the latent image in a state where the developer is insufficient. This can prevent the quality of development from deteriorating. Therefore, it is possible to always obtain good development accuracy.

  In addition, according to the present invention, the configuration can be simplified, and the developer supplied to the storage unit can be reliably prevented from being distributed only in a part to be supplied. As a result, the developer can be smoothly supplied from the developer container to the storage unit without delay.

  In addition, according to the present invention, it is possible to reliably prevent the developer supplied to the storage portion from being distributed unevenly only in a part to be supplied. As a result, the developer can be smoothly supplied from the developer container to the storage unit without delay.

  Furthermore, according to the present invention, the user can recognize that there is an abnormality. Thus, the user can deal with the abnormality as soon as possible.

  Furthermore, according to the present invention, it is possible to prevent the user from suddenly becoming unable to use the developing device.

  Further, according to the present invention, it is possible to prevent the development quality from being deteriorated due to the shortage of the developer.

  Furthermore, according to the present invention, it is possible to develop an image received via a communication line without degrading the quality. In addition, the image received via the communication line can be confirmed by the user as soon as possible.

  Furthermore, according to the present invention, since the image forming apparatus includes the developing device, the function of the developing device can be achieved.

  FIG. 1 is a cross-sectional view illustrating a configuration of a developing device 1 according to an embodiment of the present invention. The developing device 1 includes a developing unit 2, an intermediate hopper 3, a control unit 4, a replenishing unit 5, and a notification unit 6. The intermediate hopper 3 is detachably provided with a developer container 7. The developer container 7 includes a container body 8 and a support member 9. The container body 8 is formed in a substantially cylindrical shape and contains a developer such as toner used for electrophotographic image formation. The support member 9 supports the container body 8 so as to be rotatable around its axis L8. The developer container 7 can store 1400 grams of toner, for example. Hereinafter, the axis L8 of the container body 8 may be referred to as a rotation axis L8. The support member 9 is formed with a discharge portion 10 that discharges toner contained in the container body 8 in a part of the axial direction thereof. The developer container 7 is driven to rotate about the rotation axis L8, thereby discharging a constant amount of toner from the discharge unit 10 every rotation. The discharged toner is supplied to the intermediate hopper 3.

  The intermediate hopper 3 includes a housing 11, a stirring unit 13, a supply roller 14, and a first detection unit 15. The intermediate hopper 3 temporarily stores the toner replenished from the developer container 7 and supplies the stored toner to the developing unit 2. The housing 11 is a storage unit, and temporarily stores toner replenished from the developer container 7. The housing 11 is formed with a storage space 11a for storing toner. The inner peripheral surface of the lower part 11b of the housing 11 is formed in a curved surface convex downward. The lower portion 11b of the housing 11 is formed in one semi-cylindrical shape obtained by dividing the cylinder into two by a virtual plane parallel to an axis (hereinafter referred to as “housing axis”) L11, and a cross-sectional shape perpendicular to the housing axis L11. However, it becomes substantially U-shaped. The housing 11 is formed with a developer replenishment portion 12 in which toner is replenished from the developer container 7. The developer supply unit 12 is connected to the discharge unit 10 and the toner from the discharge unit 10 is supplied to the storage space 11a.

The stirring unit 13 is a stirring unit, and stirs the toner stored in the housing 11. The agitator 13 is rotatably provided around the housing axis L11 of the storage space 11a of the housing 11, and agitates the toner in the housing 11 by rotating. Further, the agitating unit 13 agitates the toner replenished from the developer container 7 by rotating, and diffuses the toner throughout the intermediate hopper 3. Further, the stirring unit 13 rotates and supplies toner to the supply roller 14.

The supply roller 14 is a supply unit, and supplies the toner stored in the housing 11 to the developing unit 2. The supply roller 14 is disposed in the storage space 11a of the housing 11 on the developing unit 2 side above the housing axis L11. The supply roller 14 is rotatably provided around a roller axis L14 extending in parallel with the housing axis L11. A developer supply hole 16 penetrating in a slit shape is formed in the housing 11 below the supply roller 14. The toner applied to the supply roller 14 by the stirring unit 13 adheres to the supply roller 14. When the supply roller 14 rotates around the roller axis L14, the toner adhering to the surface portion of the supply roller 14 is scraped off. The scraped toner passes through the developer supply hole 16 and is supplied to the developing unit 2 by being diffused over the entire axial direction through a connecting hole 18 formed in the developing tank 17 of the developing unit 2. The outer periphery of the supply roller 14 is formed of sponge, and its rotation is controlled. Thus, the supply roller 14 supplies an appropriate amount of toner to the developing unit 2 in a fine powder state.

The first detection unit 15 is a first detection unit that detects the amount of toner that is temporarily stored in the housing 11. The first detection unit 15 provides the control unit 4 with information based on the toner storage amount. The first detection unit 15 includes a detection auxiliary member 19, a holding body 20, and a magnetic permeability sensor 21.

The developing unit 2 includes a developing tank 17, an auxiliary roller 22, a stirring roller 23, a developing roller 24, and a second detection unit 25. The developing unit 2 develops the electrostatic latent image formed on the photosensitive drum 27 constituting the image forming apparatus 26, and a toner image corresponding to the electrostatic latent image is formed. The developing unit 2 of the present embodiment uses a dry two-component magnetic brush developing method. The developing tank 17 contains a two-component developer in which a magnetic carrier and toner are mixed in advance. The toner from the developer supply hole 16 is supplied to the developing tank 17 through a connecting hole 18 formed in the developing tank 17. The toner supplied to the developing tank 17 is supplied to the stirring roller 23 by the auxiliary roller 22. The toner supplied to the stirring roller 23 is mixed with the two-component developer stored in advance in the developing tank 17 by the stirring roller 23 . As a result, the toner concentration of the two-component developer is adjusted. The two-component developer is stirred by the stirring roller 23 and frictionally charged. The two-component developer is guided to the vicinity of the developing roller 24 by the stirring roller 23.

  The developing roller 24 is made of a nonmagnetic metal material, and is made of, for example, austenitic stainless steel such as SUS304 defined by Japanese Industrial Standard (abbreviation: JIS), aluminum alloy, brass, and the like, and is formed in a substantially cylindrical shape. The developing roller 24 includes a permanent magnet inside. Since the developing roller 24 has a permanent magnet inside, the two-component developer guided near the developing roller 24 adheres to the developing roller 24. The developing roller 24 is close to the photosensitive drum 27, and the toner attached to the developing roller 24 moves to the electrostatic latent image formed on the photosensitive drum 27, thereby forming a toner image.

The second detection unit 25 is a second detection unit and detects the amount of toner held in the development unit 2. The second detection unit 25 is configured using, for example, a magnetic permeability sensor. The magnetic permeability sensor detects a change in magnetic permeability based on a change in magnetic field. In this embodiment, the magnetic permeability sensor is realized by a differential transformer type magnetic permeability sensor. Since the second detection unit 25 is configured by using a magnetic permeability sensor, the toner holding amount in the development unit 2 can be detected with high accuracy. The second detection unit 25 gives information based on the toner holding amount to the control unit 4. The second detection unit 25 detects a toner concentration that is a ratio of toner in the two-component developer attached to the stirring roller 23. As the image is formed, the toner in the developing tank 17 decreases and the toner density in the developing tank 17 decreases. The second detection unit 25 detects a voltage based on the detected toner concentration, and detects a toner holding amount.

  The replenishing unit 5 is a replenishing unit that replenishes toner from the developer container 7 to the intermediate hopper 3. Specifically, the replenishment unit 5 rotates the developer container 7 to replenish the intermediate hopper 3 with toner.

  The notification unit 6 is a notification unit that notifies information. The notification unit 6 notifies the user of information given from the control unit 4. The notification unit 6 is realized by, for example, a display unit that displays characters or the like, or a sound generation unit that generates sound. The notification includes not only the main body of the image forming apparatus but also notification on a display of a personal computer when the personal computer or the like is connected to the image forming apparatus.

  The control unit 4 controls the replenishment unit 5 based on the information given from the first detection unit 15 and the second detection unit 25. As a result, the amount of toner stored in the intermediate hopper 3 and the amount of toner retained in the developing unit 2 can be controlled with high accuracy. Further, the control unit 4 controls the stirring unit 13 based on the information given from the first detection unit 15.

  As described above, the first detection unit 15 includes the detection auxiliary member 19, the holding body 20, and the magnetic permeability sensor 21. The holding body 20 is made of, for example, a polymer material such as PET, and is formed in a substantially rectangular film shape having one side as a longitudinal direction so as to have flexibility. The holding body 20 has one longitudinal end portion 20 a connected to the outer peripheral portion 13 a of the stirring portion 13. The thickness and width of the holding body 20 are set so as to be flexible enough to bend along the moving path formed in the toner layer 28 by the outer peripheral portion 13a.

The detection assisting member 19 changes the magnetic field at the detection position by passing through a predetermined detection position provided in the intermediate hopper 3. The detection assisting member 19 is held in the other longitudinal end 20 b of the holding body 20 and is provided in the housing 11. Detection auxiliary member 19 is made of a material having a either the magnetic and conductivity even with less. The shape of the detection assisting member 19 is not limited, but may be, for example, a substantially rectangular plate shape or a substantially circular plate shape. The thickness dimension of the detection auxiliary member 19 is determined by the weight of the detection auxiliary member 19, the resistance received from the toner when moving in the toner layer 28, the difficulty of deformation, and the like.

When stirring portion 13 rotates in the rotational direction A around the housing axis L 11, the outer peripheral portion 13a of the agitation portion 13, the thickness direction of the outer peripheral portion 13a is parallel to the radial direction. This to the extent that the upper surface 28a of the toner layer 28 is disposed in the vicinity of the housing axis L 11, when the toner is accommodated in the storage space 11a of the housing 11, the outer peripheral portion 13a of the agitation portion 13 is a medium toner layer 28 when moving around the housing axis L 11 is always pushing through the toner layer 28, so on it is rotated so as to separate the radially inner side of the outer peripheral portion 13a and the radially outer side, the outer peripheral portion 13a On the upstream side in the rotational direction A, a partially thin cylindrical movement path having the housing axis L11 as the central axis is formed. Since the holding body 20 connected to the outer peripheral portion 13a of the stirring unit 13 has flexibility, the holding body 20 is curved along the moving path formed in the toner layer 28 as described above, and While maintaining the same rotation radius as the rotation radius of the portion 13a, the rotation can be performed smoothly. Accordingly, at this time, the detection assisting member 19 held by the holding body 20 has the same rotation radius as the rotation radius of the outer peripheral portion 13 a along the movement path formed in the toner layer 28 by the outer peripheral portion 13 a of the stirring portion 13. While maintaining, it can rotate smoothly.

Therefore, when a sufficient amount of toner is accommodated in the housing 11, specifically, in the housing 11, at least the distance between the upper surface 28 a of the toner layer 28 and the housing axis L 11 is equal to that of the outer peripheral portion 13 a of the stirring portion 13. When the radius is smaller than the rotation radius, the outer peripheral portion 13 a can be buried in the toner layer 28 when rotating around the housing axis L <b> 11, so that a movement path can be formed in the toner layer 28. The detection assisting member 19 can always move along the movement path.

When the amount of toner in the housing 11 is small, the outer peripheral portion 13 a of the stirring portion 13 cannot rotate around the housing axis L 11 in the toner layer 28, and a movement path cannot be formed in the toner layer 28. The case where the amount of toner in the housing 11 is small is specifically the case where the distance between the upper surface 28a of the toner layer 28 and the housing axis L11 is larger than the rotational radius of the outer peripheral portion 13a of the stirring portion 13 in the housing 11. is there. At this time, since the holding body 20 connected to the outer peripheral portion 13a of the stirring portion 13 has flexibility, the rotation radius of the detection assisting member 19 becomes larger than the moving path of the outer peripheral portion 13a by its own weight, and the toner layer 28 The upper surface 28a is rotated while contacting.

  The magnetic permeability sensor 21 is provided facing the outer peripheral portion of the lower portion of the housing 11. When the detection assisting member 19 is moved by the rotation of the stirring unit 13 and passes through the detection position, the magnetic permeability sensor 21 moves to the detection assisting member 19 based on the change in the magnetic field at the detection position by the detection assisting member 19. A detection distance L0 is detected. The magnetic permeability sensor 21 detects a change in magnetic permeability based on a change in magnetic field, like the second detection unit 25. In this embodiment, the magnetic permeability sensor 21 is realized by a differential transformer type magnetic permeability sensor.

When at least the outer peripheral portion 13a of the stirring portion 13 rotates in the toner layer 28 accommodated in the housing 11, the detection auxiliary member 19 rotates while maintaining the rotational radius of the outer peripheral portion 13a. The detection distance L0 detected by 21 is constant. Further, when the amount of toner stored in the housing 11 decreases and the stirring unit 13 cannot rotate in the toner layer 13a, the detection assisting member 19 rotates and moves with a larger radius than the outer peripheral part 13a. As the amount of toner decreases and the upper surface 28a of the toner layer 28 falls downward, the detection distance L0 detected by the magnetic permeability sensor 21 becomes smaller. The magnetic permeability sensor 21 detects the amount of toner stored in the intermediate hopper 3 based on the detected detection distance L0.

FIG. 2 is a cross-sectional view illustrating the image forming apparatus 26 including the developing device 1. In FIG. 2, the thickness is omitted to facilitate understanding. An electrophotographic recording type image forming apparatus 26 such as a printer apparatus and a copying apparatus includes a developing apparatus 1 and an image forming apparatus main body (hereinafter, simply referred to as “apparatus main body”) 29. The apparatus main body 29 further includes a recording paper cassette 30, a photosensitive drum 27, a charging unit 3 1 , a laser exposure unit 32, a fixing unit 33, and a paper discharge tray 34.

The recording paper cassette 30 holds recording paper that is a development target on which an image is to be formed. The photosensitive drum 27 is a cylindrical drum provided with a photosensitive member on the outer peripheral portion, and rotates around its axis by a driving force from a driving unit (not shown). Charging unit 3 1, the photosensitive member is charged of the photosensitive drum 27. The laser exposure unit 32 exposes the charged photosensitive member of the photosensitive drum 27 with a laser light image to form an electrostatic latent image on the photosensitive member.

  As described above, the two-component developer is supplied to the photosensitive member of the photosensitive drum 27 on which the electrostatic latent image has been formed by the developing device 1 and developed to form a toner image corresponding to the electrostatic latent image. The photosensitive drum 27 transfers the toner image on the photosensitive drum 27 onto the recording paper fed from the recording paper cassette 30. The fixing unit 33 fixes the toner image of the recording paper to which the toner image is transferred onto the recording paper. The recording paper on which the toner image is fixed and the image is formed is discharged to the paper discharge tray 34.

  The image forming apparatus 26 is configured to be able to form an image received via a communication line. Therefore, when the image forming apparatus 26 is connected to a communication terminal apparatus such as the facsimile apparatus 35 and the electronic computing apparatus 36 via a communication line, the image transmitted from the communication terminal apparatus can be developed by the image forming apparatus 26.

  FIG. 3 is an enlarged plan view showing the vicinity of the intermediate hopper 3. The apparatus main body 29 further includes a first drive source 37, a second drive source 38, a first reduction device 39, and a second reduction device 40. Each drive source 37, 38 is realized by a motor. The first drive source 37 transmits the rotational driving force to the container body 8 via the first reduction gear 39 such as a gear. The second drive source 38 simultaneously transmits the rotational drive force to the stirring unit 13 and the supply roller 14 via the second reduction device 40 such as a gear. Therefore, the stirring unit 13 and the supply roller 14 are provided in conjunction with each other. As a result, the container body 8 rotates and replenishes the toner contained therein to the intermediate hopper 3. The stirring unit 13 rotates around the axis L11 and stirs the stored toner. The supply roller 14 rotates about the axis L14 and supplies toner to the developing unit 2. Since both the stirring unit 13 and the supply roller 14 receive the rotational driving force from the second driving source 38, the configuration can be simplified as compared with the case where the driving source is provided separately.

  FIG. 4 is a flowchart illustrating a control procedure of the developing unit 2 based on the toner holding amount in the control unit 4. In step a0, the control procedure is started in a state where the developing device 2 can be driven and there is a sufficient amount of toner capable of developing the latent image, and the process proceeds to step a1. In step a1, the control unit 4 determines whether or not a print processing instruction is given by a user or the like. If a print processing instruction is given, the process proceeds to step a2, and if not, the process returns to step a1. The printing process is a process of forming an image on a recording paper that is an object to be developed, and the developing unit 2 performs a process up to the step of developing the electrostatic latent image on the photosensitive member.

  In step a2, when the print processing is instructed, the control unit 4 controls the developing unit 2 and proceeds to step a3. The developing unit 2 is controlled by the control unit 4 and executes a developing operation. Since the developing operation is executed, the toner in the developing unit 2 is consumed. In step a <b> 3, the control unit 4 instructs the second detection unit 25 to detect the toner density. The second detection unit 25 detects the toner density based on a command given from the control unit 4. In other words, the second detection unit 25 detects the toner holding amount in the developing unit 2. The second detection unit 25 gives the detected information to the control unit 4 and proceeds to step a4. The second detection unit 25 performs detection at a constant interval, for example, an interval of 100 milliseconds while the printing process is being performed.

  In step a4, the control unit 4 compares the toner density given from the second detection unit 25 with a predetermined toner density. In other words, the control unit 4 compares the toner retention amount given from the second detection unit 25 with a predetermined first determination amount. If it is less than or equal to the first determination amount, the process proceeds to step a5. If it is greater than the first determination amount, the process proceeds to step a8. The first determination amount is set to an amount necessary to maintain a sufficiently high density of the image formed on the recording paper without the occurrence of fog on which toner adheres to the white background portion of the recording paper. The first determination amount is determined by experiment, for example.

  In step a8, the control unit 4 substitutes the value 0 for the supply duration L, and proceeds to step a9. The supply continuation time L is a value based on the time during which the toner is supplied to the developing unit 2. In step a9, the control unit 4 controls to stop the supply of toner to the developing unit 2, and returns to step a1.

  In step a5, the control unit 4 increases the supply duration L by 1 and proceeds to step a6. In step a6, the control unit 4 compares the supply continuation time L with a predetermined first determination time T. When the supply continuation time L is equal to or longer than the first determination time T, the process proceeds to step a10. When the supply continuation time L is less than the first determination time T, the process proceeds to step a7. In step a7, the control unit 4 performs control so as to supply the toner to the developing unit 2, and returns to step a1.

  In step a10, the control unit 4 stops the printing process and proceeds to step a11. In step a11, the control unit 4 controls the developing unit 2 to supply the toner to the developing unit 2 over a predetermined supply time, and proceeds to step a12. The predetermined supply time in step a11 is set to a supply time necessary for returning to a toner density sufficient to perform normal image formation. However, the toner density check is performed at the above-described fixed intervals, for example, 100 msec intervals. If the toner density returns before the predetermined supply time, the process proceeds to step a12, and the subsequent supply is not performed and the process returns to step a1.

  In step a12, the control unit 4 determines whether or not the toner density has been recovered. In other words, the control unit 4 determines whether or not the toner holding amount in the developing unit 2 has increased due to the supply operation of the intermediate hopper 3. When the toner density is recovered, the process returns to step a1, and when the toner density is not recovered, the process proceeds to step a13. In step a13, the control unit 4 controls the notification unit 6 and proceeds to step a14. The notification unit 6 notifies that the toner density does not recover. In step a14, a series of processing is ended from step a0.

  As described above, the control unit 4 is in the first state in which the holding amount detected by the second detection unit 25 is equal to or less than the first determination amount that is predetermined over the first determination time that is predetermined in step a4 and step a6. Is determined, the notification unit 6 is controlled to notify the determination result in step a13. In the first state, there is a high possibility that the developer container is empty. Therefore, since the notification unit 6 notifies the determination result, the user can recognize that the developer container 7 is empty. Further, it is possible to prevent development of the electrostatic latent image in a state where the toner is insufficient. This can prevent the quality of development from deteriorating.

  When determining that the controller 4 is in the first state, the controller 4 controls the developing unit 2 to stop the developing operation of the electrostatic latent image in step a10. Thereafter, in step a11, the control unit 4 controls the intermediate hopper 3 so as to supply toner for a predetermined supply time. The control unit 4 controls the developing unit 2 to resume the developing operation when the holding amount is increased by the supply operation of the intermediate hopper 3. As a result, the developing unit 2 can be prevented from developing in a state where the toner is insufficient. Therefore, it is possible to prevent the development quality from deteriorating. Therefore, it is possible to always obtain good development accuracy.

  In addition, the notification unit 6 notifies that it is abnormal when it is determined that the holding amount does not increase even if the supply operation is executed and that it is not in the second state described later. If the holding amount does not increase even though the intermediate hopper 3 has toner but the supply operation is executed, at least one of the developing unit 2 and the intermediate hopper 3 is abnormal.

  The reason why the toner holding amount decreases, in other words, the reason why the toner density decreases is that, for example, the amount of toner consumed in the developing unit 2 is larger than the amount of toner supplied. As a case where a large amount of toner is consumed, there is a case where a large amount of information having a larger area portion such as a photograph than character data is developed. When the toner concentration is low due to such a reason, it is possible to recover the toner concentration by interrupting the developing operation once and performing only the supply operation. When the toner density is thus recovered, the developing operation is resumed. However, if the cause is that the supply amount is reduced due to the absence of toner in the intermediate hopper 3, the user is notified that the developer container 7 is empty, and the developer container 7 is replaced. Prompt. If the toner concentration does not recover despite the presence of toner in the intermediate hopper 3, there is a high possibility that there is an abnormality, so a machine abnormality is notified. Therefore, the user can recognize that there is an abnormality. Thus, the user can deal with the abnormality as soon as possible.

  FIG. 5 is a flowchart showing a control procedure of the intermediate hopper 3 based on the toner storage amount in the control unit 4. In step b0, the control procedure is started in a state where the developing device 2 can be driven and there is a sufficient amount of toner capable of developing the latent image, and the process proceeds to step b1. In step b1, the control unit 4 determines whether or not a supply command for supplying toner to the developing unit 2 is given. If the supply command is given, the process proceeds to step b2, and if not, the process proceeds to step b8. In step b8, the control unit 4 performs control to stop the rotation of the supply roller 14, and returns to step b1. In step b2, the control unit 4 controls the supply roller 14 and the stirring unit 13, and proceeds to step b3. The supply roller 14 and the agitation unit 13 are driven to rotate and supply toner to the developing unit 2.

  In step b3, the control unit 4 determines whether or not the toner storage amount in the intermediate hopper 3 has been detected. The first detection unit 15 detects the toner storage amount based on the rotation period of the stirring unit 13, for example, 60 rotations per minute. Therefore, as described above, the interval is larger than the interval detected by the second detector 25. Therefore, it is determined whether or not the amount of toner stored in the intermediate hopper 3 is detected while the toner is being supplied from the intermediate hopper 3 to the developing unit 2. When the information based on the storage amount is given from the first detection unit 15, the control unit 4 proceeds to step b <b> 4, and otherwise returns to step b <b> 1.

  In step b4, the control unit 4 compares the toner storage amount given from the first detection unit 15 with a predetermined second determination amount. If it is less than or equal to the second determination amount, the process proceeds to step b5. If it is greater than the second determination amount, the process proceeds to step b9. The second determination amount is set to, for example, the minimum amount that the toner in the intermediate hopper 3 can diffuse over the entire axial direction of the developing unit 2. Thus, the toner in the intermediate hopper 3 can be reliably diffused over the entire axial direction of the developing unit 2.

  In step b9, the control unit 4 substitutes the value 0 for the replenishment duration N, and proceeds to step b10. The replenishment duration N is a value based on the time during which toner is replenished to the intermediate hopper 3. In step b10, the control unit 4 controls the replenishment unit 5 to stop the toner replenishment to the intermediate hopper 3, and returns to step b1.

  In step b5, the control unit 4 increases the replenishment duration N by 1 and proceeds to step b6. In step b6, the control unit 4 compares the replenishment duration N with a predetermined second determination time M. If the replenishment duration N is equal to or longer than the second determination time M, the process proceeds to step b11. If the replenishment duration N is less than the second determination time M, the process proceeds to step b7. In step b7, the control unit 4 replenishes toner to the intermediate hopper 3, and returns to step b1.

  In step b11, the control unit 4 gives an instruction to the notification unit 6 to control, and then proceeds to step b12. The notification unit 6 notifies that the developer container 7 is empty. In step b12, the series of processes is ended from step b0.

  In this way, the control unit 4 is in the second state in which the storage amount detected by the first detection unit 15 is equal to or less than the second determination amount that is predetermined in step b4 and step b6 over the predetermined second determination time. Is determined, the notification unit 6 is controlled to notify the determination result in step b11. In the second state, there is a high possibility that the developer container 7 is empty. Therefore, since the notification unit 6 notifies the determination result, the user can recognize that the developer container 7 is empty. Further, it is possible to prevent development of the electrostatic latent image in a state where the toner is insufficient. This can prevent the quality of development from deteriorating.

  In this way, the control unit 4 controls the replenishment unit 5 that replenishes toner when the storage amount detected by the first detection unit 15 is equal to or less than a predetermined second determination amount. In the present embodiment, the second determination amount and the replenishment amount are set to the same amount. Therefore, it is possible to prevent the storage amount from being equal to or less than the second determination amount. Thus, the supply of toner from the intermediate hopper 3 to the developing unit 2 is not delayed due to the shortage of toner in the intermediate hopper 3. Therefore, the developer can be smoothly supplied from the intermediate hopper 3 to the developing unit 2.

  Further, even when the control unit 4 determines that the state is at least one of the first state and the second state, when the holding amount is equal to or greater than the minimum holding amount, the developing unit 2 continues the developing operation. May be controlled. If the holding amount is equal to or higher than the minimum holding amount, the development quality does not deteriorate. Therefore, even if it is determined that the state is at least one of the first state and the second state, the development quality is not deteriorated even if the development operation is not stopped immediately, and therefore the development operation is executed. As a result, for example, if only one sheet is printed, all the developing operations are completed. However, since there is no toner in the intermediate hopper 3, the developing operation cannot be executed. However, since there is more than the minimum holding amount of the developing unit 2, it is possible to improve the user's convenience without causing the contradiction state that the developing operation can be executed.

  The control unit 4 may control the developing unit 2 to stop the developing operation until the toner is supplied from the developer container 7 after the developing operation is completed. Thus, before the toner is replenished, the developing operation can be continued to prevent the toner from being insufficient. Therefore, it is possible to prevent the development quality from deteriorating due to the lack of toner. Further, it is possible to prevent the holding amount from becoming too small, causing carrier adhesion, and damaging the fixing unit and the photoconductor. Therefore, when the developing operation in progress is completed, a new developing operation is not executed until the developer container 34 is replaced with a new one. It is unclear how much volume the new development operation has. Therefore, the toner may be reduced on the way, and the developing operation may not be continued. In order to avoid such a situation, when the previous development operation is completed, the new development operation is controlled to be executed after the toner is replenished. Therefore, it is possible to always perform high quality development.

  FIG. 6 is a flowchart showing a control procedure of the developer container 7 in the control unit 4. In step c0, the control procedure is started in a state where the developing device 2 can be driven and the developer container 7 has a sufficient amount of toner, and the process proceeds to step c1. In step c1, the control unit 4 determines whether or not a supply command for supplying toner to the intermediate hopper 3 is given. If the replenishment command is given, the process proceeds to step c2, and if not, the process proceeds to step c6.

  In step c6, the control unit 4 controls the replenishment unit 5 to stop the replenishment operation of the developer container 7 and returns to step c1. In step c2, the control unit 4 controls the replenishing unit 5 to rotate the developer container 7 over a predetermined driving time t, replenishes the intermediate hopper 3, and proceeds to step c3. The driving time t is set to, for example, about half of the time from the predetermined second determination amount until full replenishment.

  In step c3, the control unit 4 determines whether or not a replenishment operation for replenishing toner to the intermediate hopper 3 is performed. If the replenishment operation is performed, the process proceeds to step c5, and if not, the process proceeds to step c4. In step c4, the control unit 4 controls the stirring unit 13 to stir the toner stored in the intermediate hopper 3, and proceeds to step c5. In step c5, the control unit 4 controls the replenishing unit 5 to rotationally drive the developer container 7 over the driving time t, and returns to step c1. Accordingly, toner is supplied to the intermediate hopper 3.

  Thus, when the toner is replenished by the replenishment unit 5, the control unit 4 controls the agitation unit 13 so that the toner is agitated. In other words, the control unit 4 controls the agitation unit 13 to agitate the toner for a predetermined time when the agitation unit 13 is not operating while the toner is being replenished by the replenishment unit 5. In order to simplify the mechanism of the developing device 1, it is preferable that the agitation unit 13 of the intermediate hopper 3 is linked with the supply roller 14 and agitates when the toner is supplied to the development unit 2. However, although there is no supply from the intermediate hopper 3 to the developing unit 2, replenishment from the developer container 7 to the intermediate hopper 3 may be performed. In such a case, toner accumulates in the vicinity of the developer replenishment portion 12 to the intermediate hopper 3, and the replenishment to the intermediate hopper 3 may not work well. In order to prevent such a problem, the agitation unit 13 is operated when toner is supplied from the developer container 7 to the intermediate hopper 3. As a result, the toner is replenished to the intermediate hopper 32 by the replenishing unit 5, and it is possible to reliably prevent the toner from being unevenly distributed only in a part to be replenished. As a result, toner can be smoothly supplied from the developer container 7 to the intermediate hopper 32 without stagnation.

  Note that the state of step c4 indicates that the toner density in the developing unit 2 is sufficient. However, since the stirring unit 13 and the supply roller 14 operate in conjunction with each other, unnecessary toner is supplied to the developing unit 2 when the stirring unit 13 is operated. Therefore, it is preferable that the driving time t in step c4 is a short time enough to level the toner in the intermediate hopper 3. As a result, unnecessary toner supply to the developing unit 2 can be prevented. If it is impossible to level the toner in the intermediate hopper 3 only in a short time, the stirring operation may be performed intermittently in a plurality of times.

  Further, the developing device 1 may be provided with an input unit that is operated by a user to input a supply command for supplying toner from the developer container 7 to the intermediate hopper 3. The control unit 4 controls the replenishment unit 5 to replenish toner based on the replenishment command given from the input unit 85. Therefore, the user can intentionally supply toner to the intermediate hopper 3. The user can replenish toner to the intermediate hopper 3 and can improve the convenience of the developing device 1. For example, when transporting the machine, the intermediate hopper 3 is not filled with toner in order to prevent the intermediate hopper 3 from scattering. By doing this after the machine is installed, a sufficient amount of toner can be supplied to the intermediate hopper 3. Accordingly, quick replenishment is possible in response to a replenishment command from the developing unit.

  In addition, the control unit 4 determines that the state is at least one of the first state and the second state, and forms an image received via the communication line after the developing operation being performed is completed. As for the developing operation, the developing unit 2 is controlled to execute the developing operation. As for the remaining developing operation, the developing unit 2 is controlled by the control unit 4 so as to stop the developing operation until the toner is supplied from the developer container 7. A transmission source that transmits an image via a communication line cannot recognize the state of the development device 1 if the transmission source is located away from the received development device 1. When the remaining developing operation is executed, there is a high possibility that the user is in the vicinity of the image forming apparatus 30, so that it is easy to deal with problems such as toner shortage. The communication terminal device transmits image information from a remote place via a telephone line or the like. Therefore, it is difficult to understand the situation of the image forming apparatus 26 on the receiving side. If the developing operation cannot be executed due to lack of toner, the communication terminal device may not know the fact and may send it many times. By allowing only the image output of the communication terminal device, it is not necessary to record the image of the communication terminal device in the image memory, and an immediate visualization of information can be achieved. In particular, when toner is replenished at night or after a holiday, it is possible to prevent waiting for image output from the image memory in which the image of the communication terminal device is recorded. When copying or printing, the image output person can check the output image. Therefore, when the remaining development operation is executed, the user is relatively near the image forming apparatus 30. Because it is easy, it does not prevent immediate visualization of information. Therefore, since the developing operation is executed with priority over the remaining developing operations, the image received via the communication line can be developed without degrading the quality.

1 is a cross-sectional view illustrating a configuration of a developing device 1 according to an embodiment of the present invention. 2 is a cross-sectional view illustrating an image forming apparatus 26 including the developing device 1. FIG. It is a top view which expands and shows the intermediate hopper 3 vicinity. 4 is a flowchart illustrating a control procedure of the developing unit 2 based on a toner holding amount. 4 is a flowchart illustrating a control procedure of the intermediate hopper 3 based on a toner storage amount. 4 is a flowchart showing a control procedure of the developer container 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing device 2 Developing unit 3 Intermediate hopper 4 Control unit 5 Replenishing unit 6 Notifying unit 7 Developer container 13 Stirring unit 14 First detecting unit 25 Second detecting unit 26 Image forming device 35 Facsimile device 36 Electronic computer

Claims (8)

A developing unit for developing the latent image with a developer;
A storage portion that has an inner peripheral surface that is convex downward, and that temporarily stores the developer replenished from the developer container in a storage space formed by the inner peripheral surface ;
Replenishment means for replenishing the developer from the developer container to the reservoir;
Supply means for supplying the developer stored in the storage unit to the developing unit;
An agitation means comprising an outer peripheral portion that is rotationally driven around an axis, and agitating the developer stored in the storage portion by the rotational driving of the outer peripheral portion;
It is made of a material that has flexibility, is formed into a film, and has one end connected to the outer peripheral portion and at least one of magnetic and conductive, and is formed on the other end of the holding body. A detection auxiliary member to be held and a magnetic permeability sensor that is provided facing the outer peripheral surface of the storage unit and detects a change in the magnetic field at a predetermined position, and detects the amount of developer stored in the storage unit First detection means;
Second detection means for detecting the amount of developer held in the developing section;
An informing means for informing the information;
The first state in which the retention amount detected by the second detection means is equal to or less than the predetermined first determination amount over the predetermined first determination time, and the storage amount detected by the first detection means over the predetermined second determination time. And a control unit that controls the notification unit so as to notify the determination result when it is determined that the determination is in at least one of the second states that are equal to or less than a predetermined second determination amount. Developing device. The stirring means stirs the developer stored in the reservoir section in conjunction with the operation of the supply means,
2. The control unit according to claim 1, wherein the control unit controls the stirring unit so as to stir the developer for a predetermined time when the stirring unit is not operating while the developer is being supplied to the reservoir by the supply unit. Development device. Control means, when the storage amount detected by the first detecting means comprises the following main replenishing amount predetermined to control the replenishing means for replenishing the developer, when the developer is replenished by the replenishing means, a developer The developing device according to claim 1, wherein the agitation unit is controlled to agitate the toner.   If it is determined that the control unit is in the first state, the control unit controls the developing unit to stop the developing operation of the latent image, and then controls the supply unit to supply the developer over a predetermined supply time. When the holding amount increases due to the operation, the developing unit is controlled to resume the developing operation, and it is abnormal when it is determined that the holding amount does not increase even if the supply operation is executed and that the holding state is not in the second state. The developing device according to claim 1, wherein the notifying unit is controlled so as to notify the user.   Even if it is determined that the control unit is in at least one of the first state and the second state, the developing operation is continued when the holding amount is equal to or greater than the minimum holding amount capable of developing the latent image. The developing device according to claim 1, wherein the developing unit is controlled to do so.   6. The developing device according to claim 5, wherein the control unit controls the developing unit so as to stop the developing operation until the developer is supplied from the developer container after the developing operation is completed. A developing device provided in an image forming apparatus capable of forming an image received via a communication line,
After completion of the developing operation, the control means executes the developing operation for the developing operation for forming the image received via the communication line, and the developer is supplied from the developer container for the remaining developing operation. 6. The developing device according to claim 5, wherein the developing unit is controlled so as to stop the developing operation until it is done.   An image forming apparatus comprising the developing device according to claim 1.

Images