JP6112411B2 - DEVELOPING DEVICE, IMAGE FORMING DEVICE HAVING THE SAME, AND PROCESS CARTRIDGE - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device including a flexible seal member for preventing toner scattering used in an image forming apparatus such as a copying machine, a fax machine, and a printer, and an image forming apparatus and a process cartridge including the developing device. Is.

  2. Description of the Related Art Conventionally, a developing device that visualizes a latent image formed on a latent image agent carrier with a developing device is known. For example, there is a two-component developing device using a two-component developer composed of a toner and a carrier as a developer in order to visualize a latent image formed on a photoreceptor as a latent image agent carrier. In this two-component developing device, a toner is supplied by bringing a magnetic brush of a developing roller, which is a developer carrying member, into contact with a photosensitive member, and is attached to a latent image on the photosensitive member to make a visible image. Then, a phenomenon occurs in which part of the toner supplied from the developer magnetic brush scatters to the outside without adhering to the photoconductor in the developing region (hereinafter referred to as “toner scatter”), and is caused by the scattered toner. It is known that problems such as in-flight contamination and abnormal images occur. For this reason, conventionally, a flexible seal member, generally called an inlet seal, has been arranged in the vicinity of the developing area between the photosensitive member and the developing roller, upstream of the rotating direction of the photosensitive member of the magnetic brush. A structure for reducing the above is known.

  Patent Document 1 describes a developing device that movably supports a unit having a flexible inlet seal so that the amount of the inlet seal that abuts against the photoreceptor can be adjusted to an appropriate range. Yes. This developing device prevents the toner from scattering from the upstream side in the rotation direction of the photosensitive member in the developing region by making the amount of contact of the inlet seal with the photosensitive member within an appropriate range, and the amount of contact exceeds the appropriate range. This is to suppress the problems that occur.

  Japanese Patent Application Laid-Open No. 2005-228561 describes a developing device that uses a U-shaped inlet seal and eliminates a gap between the photoreceptor and the inlet seal without requiring high processing accuracy and installation accuracy. This developing device eliminates the gap between the inlet seal and the photosensitive member by always bringing the entire contact portion of the inlet seal into contact with the photosensitive member without requiring high processing accuracy and installation accuracy. This prevents toner scattering from the upstream side in the rotation direction.

  In a developing device provided with such an inlet seal, generally, toner gradually accumulates and accumulates on the inlet seal. For this reason, the toner accumulated on the entrance seal is adsorbed to the photoconductor side by the surface potential of the photoconductor, which causes a problem that an abnormal image such as a background stain or a toner drop image is caused.

  In order to solve this problem, Patent Document 3 proposes a developing device in which an inlet seal is supported by a case of the developing device in a movable state. In this developing device, the inlet seal selectively contacts either the photoconductor or the developing roller in conjunction with the operation of the developing device. According to this developing device, the toner collected on the inlet seal can be collected in the developing device by the entrance seal contacting the developing roller.

  However, in the developing device disclosed in Patent Document 3, when the inlet seal contacts the developing roller, the toner accumulated on the inlet seal spills from the inlet seal, thereby causing in-machine contamination and abnormal images. There was a problem. Hereinafter, this problem will be described with reference to the drawings.

17 and 18 are schematic views showing an example of the developing device in which the inlet seal is supported by the case of the developing device in a movable state.
An inlet seal 66 of the developing device is held at one end of an inlet seal holder 67 formed in a substantially square shape. The inlet seal holder 67 is supported so as to be rotatable about a rotation center B near the folding point of the dogleg shape. As the entrance seal holder 67 rotates about the rotation center B, the entrance seal 66 contacts either the photosensitive drum 1 or the developing roller 51. Which of the inlet seals 66 abuts can be selected by controlling the rotation of the inlet seal holder 67 by a cam 68 that abuts the other end of the inlet seal holder 67. As shown in FIG. 17, the toner is accumulated on the inlet seal 66 when the image forming operation is performed in a state where the inlet seal 66 is in contact with the photosensitive drum 1. The toner accumulated in this manner is moved onto the developing roller 51 and collected in the developing device 5 by bringing the inlet seal 66 into contact with the developing roller 51 as shown in FIG.

  In this configuration, the toner deposited on the inlet seal 66 accumulates in a space between the doctor blade 52 as the developer regulating member and the inlet seal 66 and the inlet seal holder 67 as shown in FIG. Therefore, when the entrance seal holder 67 is rotated so that the entrance seal 66 is brought into contact with the developing roller 51 in a state where a large amount of toner is accumulated in this space, as shown in FIG. A part passes over the tip of the inlet seal 66 and leaks from the gap between the inlet seal 66 and the photosensitive drum 1.

  The toners T1, T2 and T3 leaking out in this way become scattered toners, which pollutes the inside of the machine or causes abnormal images. In particular, in the image forming apparatus in which the optical writing unit is disposed below the developing device 5, the leaked toners T1, T2, and T3 fall toward the optical writing unit, causing the writing optical path to become dirty, white streaks, etc. An abnormal image occurs. Further, in the image forming apparatus in which the intermediate transfer member and the recording paper conveyance path are arranged below the developing device 5, the leaked toners T1, T2, and T3 fall on the intermediate transfer member to generate a toner drop image or the like. Causes abnormal images or soils the recording paper.

  The present invention has been made in view of the above problems, and an object of the present invention is to switch the contact partner of the flexible seal member from the latent image carrier to the developer carrier to change the contact partner on the flexible seal member. By providing a developing device and an image forming apparatus capable of suppressing the accumulated toner from moving over the tip of the flexible seal member and scattering outside the developing device when the deposited toner is moved onto the surface of the developer carrying member. is there.

  In order to achieve the above object, the present invention provides a developing case in which a developer containing toner is accommodated, a developer carrying member that carries the developer on the surface and moves, and a tip portion that carries a latent image. A flexible seal member that closes a gap between the surface of the latent image carrier and the developing case by abutting on the surface of the body and suppresses toner from being scattered outside the developing device. The flexible seal member is movable so that the tip portion thereof is selectively brought into contact with the surface of the latent image carrier or the surface of the developer carrier with the tip portion thereof facing upward. In the developing device in which the end opposite to the tip is supported by the developing case, the flexible seal member is in a scattering prevention state in which the tip is in contact with the surface of the latent image carrier. Moves to a toner collecting state in contact with the surface of the developer carrying member Position of the tip portion to come is characterized by being configured to extend.

  In the present invention, the tip of the flexible seal member is brought into contact with the surface of the developer carrying member from the scattering prevention state in which the tip of the flexible sealing member is in contact with the surface of the latent image carrier. It is possible to switch to a toner collecting state to be brought into contact with the toner. As a result, the accumulated toner on the flexible seal member can be moved to the surface of the developer carrying member and collected. At this time, in the present invention, when the flexible seal member moves from the scattering prevention state to the toner recovery state, the position of the distal end portion of the flexible seal member extends upward. Therefore, as compared with the conventional configuration in which the position of the tip portion of the flexible seal member does not extend, when the flexible seal member moves to the toner recovery state, the toner deposited on the flexible seal member Thus, it is possible to suppress the scattering from the gap between the distal end portion of the flexible seal member and the latent image carrier surface over the distal end portion of the flexible seal member.

  According to the present invention, when collecting the accumulated toner on the flexible seal member into the developing device by switching the contact partner of the flexible seal member from the latent image carrier to the developer carrier, An excellent effect is obtained in that it is possible to prevent the flexible seal member from getting over the tip of the flexible seal member and being scattered outside the developing device.

1 is a schematic diagram illustrating an overall configuration of an image forming apparatus according to an embodiment. 2 is a schematic diagram illustrating an image forming unit of the image forming apparatus. FIG. FIG. 4 is a schematic diagram illustrating a toner scattering prevention configuration when an inlet seal provided in the developing device of the image forming apparatus is in a scattering prevention state. FIG. 6 is a schematic diagram illustrating a configuration for preventing toner scattering when the same entrance seal is in a toner recovery state. (A)-(c) is explanatory drawing which shows operation | movement of the same entrance seal. 6 is a graph showing the relationship between the number of sheets passed and the toner charge amount. It is a graph which shows the relationship between the toner accumulation amount on an entrance seal, and the image area ratio of the image to form. 6 is a graph showing the relationship between the number of sheets passing through and the toner charge amount according to the temperature and humidity environment. It is a graph which shows the relationship between the toner accumulation amount on an entrance seal, and a temperature / humidity environment. 6 is a flowchart illustrating a process in which a control unit of the copier according to the embodiment acquires information for determining toner collection timing. It is explanatory drawing for demonstrating the content of the mileage recording table recorded on the recording means which the control part can access. 6 is a flowchart for controlling a toner recovery timing at which an entrance seal shifts from a scattering prevention state to a toner recovery state. FIG. 6 is a schematic diagram illustrating a toner scattering prevention configuration when an inlet seal provided in a developing device of an image forming apparatus according to a second embodiment is in a scattering prevention state. FIG. 6 is a schematic diagram illustrating a configuration for preventing toner scattering when the same entrance seal is in a toner recovery state. FIG. 10 is a schematic diagram illustrating a toner scattering prevention configuration when an inlet seal according to Modification 1 is in a scattering prevention state. FIG. 6 is a schematic diagram illustrating a toner scattering prevention configuration when an inlet seal is in a toner recovery state. It is a schematic diagram showing an example of a conventional developing device when the inlet seal supported by the case of the developing device in a movable state is in a scattering prevention state. It is a schematic diagram showing an example of a conventional developing device when the same entrance seal is in a toner recovery state. (A) And (b) is explanatory drawing which shows the mode of the toner when the developing roller is rotationally driven in the same direction as that during the image forming operation when the entrance seal is shifted to the toner collecting state in Modification 2. . (A) And (b) is explanatory drawing which shows the mode of the toner when the developing roller is rotationally driven in the direction opposite to that during the image forming operation when the entrance seal is shifted to the toner recovery state in Modification 2. is there. 10 is an explanatory diagram for explaining the contents of a collection operation number determination table recorded in a recording means accessible by a control unit of a copying machine in Modification 2. FIG.

Embodiment 1
Hereinafter, an embodiment (hereinafter referred to as “embodiment”) in which the developing device according to the present invention is applied to a full-color printer (hereinafter simply referred to as “printer”) that is an intermediate transfer type tandem image forming apparatus. 1 ”) will be described with reference to the drawings.

First, an outline of the printer 100 will be described with reference to FIGS. 1 and 2.
FIG. 1 is a schematic diagram illustrating the overall configuration of the printer according to the first embodiment.
The printer 100 is conveyed from the upper part of the main body to a stack unit 30 on which the recording paper P on which an image has been formed is stacked, a discharge roller pair 29 that discharges the recording paper P to the stack unit 30, and a discharge roller pair 29. A fixing unit 20 for fixing the toner image on the recording paper P is provided. A toner replenishing device 31 is provided on the left side of the fixing unit 20 in FIG. 1, and an intermediate transfer unit 15 is provided below the fixing unit 20 and the toner replenishing device 31. A secondary transfer roller 19 is provided on the right side of the intermediate transfer unit 15 in FIG. Below the intermediate transfer unit 15, four image forming units 6Y, 6M, 6C, and 6K corresponding to the respective colors (yellow, magenta, cyan, and black) are provided. An exposure unit 7 for irradiating L is provided. Below the exposure unit 7, two paper feeding units 26 for stacking and storing the recording paper P are provided. From the right side in FIG. 1 of these paper feeding units 26, the secondary transfer roller 19 and the fixing unit 20 are passed through. Thus, a transport path for transporting the recording paper P is provided to the paper discharge roller pair 29.

  In the toner supply device 31, four toner cartridges (toner containers) 32Y, 32M, 32C, and 32K corresponding to the respective colors (yellow, magenta, cyan, and black) are detachably (replaceable). A portion other than the toner cartridge in the toner replenishing device 31 is a toner conveying device that conveys toner, which is a powdery image forming agent, discharged from the toner cartridge to a developing device, which will be described later.

  The fixing unit 20 includes a heating and pressing type fixing device that fixes the color image transferred onto the surface of the recording paper P by heat and pressure generated by the fixing roller and the pressure roller.

  The intermediate transfer unit 15 includes an intermediate transfer belt 8 as an intermediate transfer member, four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14, and the like. Has been. A belt cleaning device 10 as an intermediate transfer cleaning unit is also provided.

  The secondary transfer roller 19 faces the secondary transfer backup roller 12 via the intermediate transfer belt 8 of the intermediate transfer unit 15 described above.

  The image forming units 6Y, 6M, 6C, and 6K corresponding to the respective colors are arranged in parallel so as to face the intermediate transfer belt 8 of the intermediate transfer unit 15 described above. Each of the image forming units 6Y, 6M, 6C, and 6K is a process cartridge that is configured so that at least the photosensitive drum 1 and the developing device 5 are supported on a common support, and are detachable integrally with the printer main body. It is configured. The image forming units 6Y, 6M, 6C, and 6K have the same configuration and operation except for the color of the toner to be used. Therefore, in the following description, Y, M, C, and K are classified as appropriate. Description will be made with the reference numerals omitted.

FIG. 2 is a schematic diagram showing the image forming unit 6 of the printer.
The image forming unit 6 includes a photosensitive drum 1 as a latent image carrier, a charging device 4 provided around the photosensitive drum 1, a developing device 5, a photosensitive member cleaning device 2, a charge eliminating unit (not shown), and the like. It consists of Then, an image forming process (charging process, exposure process, developing process) is performed on the photosensitive drum 1, and a toner image is formed on the photosensitive drum 1.

  The photosensitive drum 1 is rotationally driven in a clockwise direction in FIG. 2 by a drive motor (not shown). Then, the surface of the photosensitive drum 1 is uniformly charged at the charging position by the charging device 4 (charging process). Thereafter, the surface of the photosensitive drum 1 reaches the irradiation position of the laser beam L irradiated from the exposure unit 7 (see FIG. 1), and an electrostatic latent image is formed by exposure scanning at this position (exposure process). . Specifically, the exposure unit 7 emits a laser beam L from a light source, and scans the laser beam L with a polygon mirror, which is a rotationally driven rotary polygon mirror, on a photosensitive drum via a plurality of optical elements. Irradiate. Thereafter, the photosensitive drum 1 and the developing roller 51 of the developing device 5 reach a developing area where the photosensitive drum 1 and the developing roller 51 are opposed to each other, and the electrostatic latent image is visualized by attaching the toner (developing process).

  Thereafter, the surface of the photosensitive drum 1 passes through a primary transfer area facing the intermediate transfer belt 8, and the toner image on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 8 in the primary transfer area. (Primary transfer process). The untransferred toner remaining on the photosensitive drum 1 is mechanically scraped and collected by the cleaning blade 2a at a position facing the photosensitive member cleaning device 2 (cleaning step). Finally, the surface of the photoconductive drum 1 reaches a position facing a static eliminating unit (not shown), and the residual potential on the photoconductive drum 1 is removed at this position. In this way, a series of image forming processes performed on the photosensitive drum 1 is completed.

  The intermediate transfer belt 8 is stretched and supported by three rollers 12 to 14 and is endlessly moved in the direction of the arrow in FIG. The four primary transfer bias rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1K to form primary transfer nips. A transfer bias having a polarity opposite to that of the toner is applied to the primary transfer bias rollers 9Y, 9M, 9C, and 9K. The intermediate transfer belt 8 travels in the direction of the arrow, and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9K. In this manner, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8, and a color image is formed on the intermediate transfer belt 8.

  The intermediate transfer belt 8 on which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19. At this position, the secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 8 are transferred onto a recording paper P such as a transfer paper conveyed to the position of the secondary transfer nip (secondary transfer step). At this time, untransferred toner that has not been transferred to the recording paper P remains on the intermediate transfer belt 8, but untransferred toner on the intermediate transfer belt 8 is collected at the position of the belt cleaning device 10.

  Here, the recording paper P transported to the position of the secondary transfer nip is transported from the paper feed unit 26 disposed below the printer 100 main body via the paper feed roller 27, the registration roller pair 28, and the like. It has been done. Specifically, a plurality of recording papers P such as transfer papers are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is driven to rotate counterclockwise in FIG. 1, the uppermost recording paper P is fed between the rollers of the registration roller pair 28.

  The recording paper P conveyed to the registration roller pair 28 temporarily stops at the position of the roller nip of the registration roller pair 28 whose rotation drive has been stopped. Then, the registration roller pair 28 is rotationally driven in time with the color image on the intermediate transfer belt 8, and the recording paper P is conveyed toward the secondary transfer nip. Thus, a desired color image is transferred onto the recording paper P.

  Thereafter, the recording paper P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the recording paper P by heat and pressure generated by the fixing roller and the pressure roller. Thereafter, the recording paper P is discharged outside the apparatus through a pair of paper discharge rollers 29. The recording paper P discharged to the outside of the apparatus by the paper discharge roller pair 29 is sequentially stacked on the stack unit 30 as an output image. In this way, a series of image forming processes in the printer is completed.

Next, the configuration and operation of the developing device 5 in the image forming unit 6 which is a characteristic part of the present invention will be described in more detail.
As shown in FIG. 2, the developing device 5 of Embodiment 1 includes a developing roller 51 that is a developer carrying member facing the photosensitive drum 1, a doctor blade 52 facing the developing roller 51, a developer containing portion 53, The conveyance screw 55 which is two conveyance members in 54 is provided. In addition, a toner density sensor 56 that detects the toner density in the developer, the tip part contacts the surface of the photosensitive drum 1 to close the gap between the surface of the photosensitive drum and the developing case, and the toner is scattered outside the developing device. An inlet seal 57 or the like as a flexible seal member that suppresses this is also provided.

  The developing roller 51 includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. In the developer accommodating portions 53 and 54, a two-component developer G containing a carrier and toner is accommodated. The developer accommodating portion 54 communicates with the toner transport pipe 43 that is a toner replenishment path through an opening formed thereabove.

  The sleeve of the developing roller 51 is driven to rotate counterclockwise, which is the direction of the arrow in FIG. The developer G carried on the developing roller 51 by the magnetic field formed by the magnet is conveyed as the developing roller 51 rotates. Here, the developer G in the developing device 5 is adjusted so that the toner concentration (toner concentration) in the developer is detected by the toner concentration sensor 56 and the toner concentration falls within a predetermined range. Specifically, the toner accommodated in the toner cartridge 32 is replenished into the developer accommodating portion 54 via the toner conveyance pipe 43 according to the toner consumption amount in the developing device 5.

  The toner replenished in the developer accommodating portion 54 is mixed and stirred together with the developer G by the two conveying screws 55, and the two developer accommodating portions 53 and 54 are moved in a direction perpendicular to the paper surface in FIG. Move and circulate. The toner in the developer G is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51 together with the carrier by the magnetic force formed on the developing roller 51.

  The developer G carried on the developing roller 51 is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52. The developer G on the developing roller 51 is conveyed to a developing area that is a position facing the photosensitive drum 1 after the developer amount is made appropriate at this position. The toner is attracted to the electrostatic latent image formed on the photosensitive drum 1 by the electric field formed in the development area. Thereafter, the developer G remaining on the developing roller 51 reaches the upper portion of the developer containing portion 53 as the developing roller 51 rotates, and is detached from the developing roller 51 at this position.

  In the developing area, the developer G is rubbed against the photosensitive drum 1, and at this time, toner separated from the carrier is adsorbed to the photosensitive drum 1 and floated on the space. The toner that floats downward from the developing area, that is, from the developing area toward the upstream side in the rotation direction of the photosensitive drum, is proximal to the developing case of the developing device 5 (in this embodiment, the doctor blade 52 supported by the developing case). Is prevented and scattering from the apparatus is prevented by an inlet seal 57 whose tip is in contact with the surface of the photosensitive drum 1.

  Here, the toner floating upward from the developing region is sucked into the developing device 5 and collected by a sucking airflow flowing between the inner wall of the developing case and the developing roller 51 toward the developer containing portion 53. The However, the toner floating downward from the developing area accumulates on the inlet seal 57 and accumulates. The toner deposited on the entrance seal 57 is attracted to the photoconductor 1 by the potential of the photoconductor drum 1 and may cause an abnormal image such as a background stain or a toner drop image.

  Therefore, in the first embodiment, the inlet seal 57 provided in the developing device 5 is supported by the developing case in a movable state, and the tip portion thereof is selected as either the surface of the photosensitive drum 1 or the surface of the developing roller 51. It is configured to be able to come into contact with each other. With this configuration, the scattering prevention state in which the tip of the inlet seal 57 as shown in FIG. 3 abuts against the surface of the photosensitive drum 1 and the tip of the inlet seal 57 as shown in FIG. 4 are developed. It is possible to selectively obtain the toner collection state to be brought into contact with the surface of the roller 51.

  If the entrance seal 57 is in a scattering-prevented state, the gap between the surface of the photosensitive drum and the developing case (below the development area) is closed by the entrance seal 57, and toner can be prevented from scattering outside the developing device. On the other hand, when the inlet seal 57 is in the toner recovery state, the surface of the inlet seal 57 on which the toner is accumulated is brought into contact with the surface of the developing roller 51, and the accumulated toner on the inlet seal 57 is moved to the surface of the developing roller 51. It can be removed from the inlet seal 57. With such a configuration, it is possible to stably suppress toner accumulation on the inlet seal 57 over a long period of time, and it is possible to prevent the occurrence of abnormal images due to the accumulated toner on the inlet seal 57.

For example, the following configuration can be used to switch the entrance seal 57 between the photosensitive drum 1 and the developing roller 51.
In the first embodiment, the flexible seal member is composed of an inlet seal 57 and a generally dog-shaped inlet seal holder 58 that holds the inlet seal 57. The inlet seal holder 58 is supported on a rotating shaft 59 extending along the rotating shaft of the developing roller 51 in the vicinity of the folding point of the dogleg. When the rotary shaft 59 is rotationally driven by a driving force from a drive source (not shown), the rotary shaft 59 can be rotated about the rotational center.

  One end of the inlet seal 57 (the end opposite to the tip of the inlet seal 57) is joined to one end of the inlet seal holder 58, and the tip of the inlet seal 57 is connected to the inlet seal holder 58. An inlet seal 57 is supported so as to go to the development region. As the inlet seal holder 58 rotates about the rotation shaft 59, the front end portion of the inlet seal 57 is selectively brought into contact with either the surface of the photosensitive drum 1 or the surface of the developing roller 51. In the inlet seal holder 58, the rotation of the rotary shaft 59 causes the tip of the inlet seal 57 to come into contact with the surface of the photosensitive drum 1 as shown in FIG. 3, and the development as shown in FIG. It is possible to switch to the toner collection state in contact with the surface of the roller 51.

  The rotation of the rotary shaft 59 is controlled by the control unit of the printer. Therefore, the control unit functions as a toner recovery timing control unit that controls the timing of switching the inlet seal 57 from the scattering prevention state to the toner recovery state according to a predetermined toner recovery timing. The control unit keeps the inlet seal 57 in the scattering prevention state during the image forming operation period, and the toner collection timing is set within the non-image forming operation period that is not the image forming operation period. Details of the toner collection timing will be described later.

  By the way, the toner is gradually deposited on the inlet seal 57 by setting the inlet seal 57 in the scattering prevention state. When the inlet seal 57 is switched from the scattering prevention state to the toner recovery state when a large amount of toner is accumulated on the inlet seal 57, the toner on the inlet seal 57 gets over the front end portion of the inlet seal 57, and the inlet seal 57 and the photosensitive member are exposed. It leaks from the gap between the body drum 1 and causes toner scattering. In order to prevent such toner scattering, this embodiment employs the following configuration.

5A to 5C are explanatory views showing the operation of the inlet seal 57 in the first embodiment.
In the first embodiment, the proximal end portion of the inlet seal 57 is held on one end portion (upper end portion) of the inlet seal holder 58 via the movable portion 70. The movable portion 70 is supported by the inlet seal holder 58 so as to be slidable in the direction of extending and retracting the position of the distal end portion of the inlet seal 57. On the other hand, the doctor blade 52 is provided with a projecting portion 71, and the projecting portion 71 is configured so that the lower end portion of the movable portion 70 comes into contact therewith. The movable portion 70 is configured such that the lower end portion thereof is always in contact with the protrusion 71 on the doctor blade 52 by a spring as an urging means (not shown).

  As shown in FIG. 5A, when the rotating shaft 59 is rotated and the tip of the inlet seal 57 is in a scattering prevention state where it contacts the surface of the photosensitive drum 1, the shape of the protrusion 71 causes the movable part to move. 70 slides in a direction to be accommodated in the inlet seal holder 58 and is positioned at a retracted position in which the tip of the inlet seal 57 is retracted. When the rotating shaft 59 is rotated from this state to shift to a toner collecting state where the tip of the inlet seal 57 contacts the surface of the developing roller 51, as shown in FIG. Due to the shape of the protrusion 71, the movable portion 70 slides in a direction to advance from the inlet seal holder 58 against the biasing force of the spring. Thereby, the front-end | tip part of the inlet seal 57 is extended gradually. Then, when the leading end portion of the inlet seal 57 shifts to the toner collecting state where it abuts on the surface of the developing roller 51, the inlet seal 57 is positioned at the most extended position.

  With this configuration, in the present embodiment, when the inlet seal 57 moves from the scattering prevention state to the toner recovery state, the accumulated toner on the inlet seal 57 gets over the tip of the inlet seal 57 and scatters. It is suppressed.

Next, the toner collection timing for switching from the scattering prevention state to the toner collection state will be described.
FIG. 6 is a graph showing the relationship between the number of sheets to be passed and the toner charge amount.
In general, when a two-component developer is used, the carrier basically remains in the developing device 5, so that when used for a long period of time, the surface layer of the carrier is scraped (film scraping), or inorganic fine particles externally added to the toner are removed from the carrier. The charging ability to charge the toner gradually decreases due to adhesion (spent) to the surface of the toner. A carrier having a lowered toner charging capability has a weak force for holding the toner, so that the toner is easily separated from the developing region, and the floating toner is easily generated. As the amount of floating toner increases, the amount of toner deposited on the inlet seal 57 increases. Therefore, the amount of toner deposited on the inlet seal 57 per unit time (toner deposition speed) increases as the number of sheets passed increases.

  Considering this, if the toner collection timing is constant from the initial stage to the passage of time, in the initial stage, the entrance seal 57 is changed from the scattering prevention state to the toner collection state before the toner accumulation amount on the entrance seal 57 exceeds the allowable amount. Even if the transfer is successful, the entrance seal 57 may be transferred to the toner recovery state in a state where the allowable amount is exceeded over time. In this case, toner scattering may be caused even if the configuration in which the tip of the inlet seal 57 is extended as described above. Therefore, it is preferable to change the toner collection timing for switching the inlet seal 57 to the toner collection state according to the number of sheets to be passed.

  Here, the deterioration state of the carrier is indirectly grasped by the number of sheets. However, as long as the index value has a correlation with the carrier deterioration state, the operation time of the developing device 5 is not limited to the number of sheets to be passed. Other index values may be used.

FIG. 7 is a graph showing the relationship between the toner accumulation amount on the inlet seal 57 and the image area ratio of the image to be formed.
As shown in FIG. 7, the amount of toner deposited on the inlet seal 57 tends to increase as the image area ratio of the image to be formed increases. This is because, as the image area ratio of the image to be formed is higher, more toner is consumed from the developing device 5, and as a result, a new toner replenishment amount is increased. As a result, the number of cases where toner in a state where mixing and stirring with the developer are insufficient in the developing device 5 is conveyed to the developing region increases. Such toner tends to cause toner scattering because of insufficient charge amount. Therefore, the higher the image area ratio of the image to be formed, the more toner is deposited on the inlet seal 57.

  Considering this, if the toner collection timing is constant regardless of the image area ratio of the image to be formed, the amount of accumulated toner exceeds the allowable amount in a situation where a relatively large number of images with a high image area ratio are formed. In some cases, the inlet seal 57 may be shifted to the toner recovery state. In this case, toner scattering may be caused even if the configuration in which the tip of the inlet seal 57 is extended as described above. Therefore, it is preferable to change the toner collection timing for switching the inlet seal 57 to the toner collection state according to the image area ratio of the image formed in the past.

  Here, the toner amount consumed by the image forming operation in the past predetermined period is indirectly grasped by the image area ratio, but if the index value has a correlation with the toner consumption amount, the image area Not only the rate but also other index values may be used.

FIG. 8 is a graph showing the relationship between the number of sheets passed and the toner charge amount according to the temperature and humidity environment.
FIG. 9 is a graph showing the relationship between the toner accumulation amount on the inlet seal 57 and the temperature and humidity environment.
Generally, it is known that when the usage environment is a high humidity environment, the charge amount of the toner is lower than that in a low humidity environment. For this reason, the number of cases where toner having an insufficient charge amount is transported to the development region increases, and toner scattering is likely to occur. Therefore, the higher the image area ratio of the image to be formed, the more toner is deposited on the inlet seal 57.

  Considering this, if the toner recovery timing is constant regardless of the use environment, in a high humidity environment, the entrance seal 57 may shift to the toner recovery state with the toner accumulation amount exceeding the allowable amount. . In this case, toner scattering may be caused even if the configuration in which the tip of the inlet seal 57 is extended as described above. Therefore, it is preferable to change the toner collection timing for switching the inlet seal 57 to the toner collection state according to the use environment.

FIG. 10 is a flowchart illustrating a process in which the control unit of the copier acquires information for determining toner collection timing.
FIG. 11 is an explanatory diagram for explaining the contents of a travel distance recording table recorded in recording means accessible by the control unit of the copying machine.
In the travel distance recording table, as shown in FIG. 11, the image area ratio, the environment, and the travel distance are each divided into two with A ₀ , H ₀ , and D ₀ as boundaries. Controller of the present embodiment is executed according to the flowchart showing the control A to be recorded to determine the value D ₁ to D ₈ of the eight conditions in the running distance record table in FIG. 10.

The control unit of the present embodiment executes the control shown in FIG. 10 for each image output, for example. In this control A, first, the current developing device travel distance D, the development device travel distance Dn from the previous control execution, the image area ratio (average image area ratio) A from the previous control execution, and the current absolute humidity Four pieces of information of H are acquired (S1). The absolute humidity H is calculated from the detection result of a temperature / humidity sensor (not shown). Then, the image forming sections 6Y, 6M, 6C, each 6K, determines whether or not the current developing device running distance D is smaller than the threshold value _{D 0} (S2).

For the current developing device running distance D is smaller imaging unit than D ₀ is (S2 YES in), then whether the average image area ratio A from the time of execution of the previous control A smaller than the threshold value A ₀ (S3). In this determination, (YES in S3) when it is determined that the average image area ratio A is smaller than the threshold value A _0, to D ₁ of the mileage record table stored in the storage means, during the execution of the previous control A A process of adding the developing device travel distance Dn from (S4) is executed. For example, when the developing device travel distance Dn from the execution of the previous control A is ₁ m, if D ₁ after the end of the previous control A is 5 m, the value of D ₁ is set to 5 m + 1 m = 6 m. Execute the update process. Further, when it is determined that the average image area ratio A is the threshold value A ₀ or more (S3 of NO), the D ₂ mileage record table stored in the storage means, from the time of execution of the previous control A A process of adding the developing device travel distance Dn is executed (S5).

Subsequently, it is determined whether the current absolute humidity H is smaller than the threshold value H ₀ (S6). In this determination, if it is determined that the absolute humidity H is smaller than the threshold value H ₀ (S6 of YES), the D ₃ mileage record table stored in the storage means, from the time of execution of the previous control A Processing for adding the developing device travel distance Dn is executed (S7). Further, when it is determined that the absolute humidity H is the threshold value H ₀ above (S6 of NO), the D ₄ mileage record table stored in the storage means, a developing apparatus from when the execution of the previous control A A process of adding the travel distance Dn is executed (S8).

On the other hand, the image forming unit is currently developing device running distance D is D ₀ or more (NO in S2), whether the average image area ratio A from the time of execution of the previous control A smaller than the threshold value A ₀ Is determined (S9). In this determination, (YES in S9) if it is determined that the average image area ratio A is smaller than the threshold value A _0, the D ₅ mileage record table stored in the storage means, during the execution of the previous control A A process of adding the developing device travel distance Dn from (S10) is executed. Further, when it is determined that the average image area ratio A is the threshold value A ₀ or more (in S9 NO), the D ₆ mileage record table stored in the storage means, from the time of execution of the previous control A A process of adding the developing device travel distance Dn is executed (S11).

Subsequently, it is determined whether the current absolute humidity H is smaller than the threshold value H ₀ (S12). In this determination, if it is determined that the absolute humidity H is smaller than the threshold value H ₀ (S12 of YES), the D ₇ mileage record table stored in the storage means, from the time of execution of the previous control A A process of adding the developing device travel distance Dn is executed (S13). Further, when it is determined that the absolute humidity H is the threshold value H ₀ above (S12 of NO), the D ₈ mileage record table stored in the storage means, a developing apparatus from when the execution of the previous control A A process of adding the travel distance Dn is executed (S14).

FIG. 12 is a flowchart for controlling the toner recovery timing at which the inlet seal 57 is shifted from the scattering prevention state to the toner recovery state.
This toner collection timing control B is executed, for example, at the end of the image forming operation (at the end of the print job). When the execution of the control B is started, the control unit of the present embodiment first reads the values D ₁ to D ₈ of mileage record table from the storage means, the values D ₁ to D ₈ are respectively corresponding to It is determined whether or not the threshold _values D _{1th to} D _8th are exceeded (S21). In this determination, if it is determined that none of the values D _{1 to} D ₈ exceed the threshold values D _{1th to} D _8th (NO in S21), the control B is terminated as it is.

On the other hand, if it is determined that any one of the values D _{1 to} D ₈ exceeds the threshold values D _{1th to} D _8th (YES in S21), the scattering-prevented entrance seal that is in contact with the surface of the photosensitive drum 1 is determined. The inlet seal holder 58 is rotated by controlling the rotation of the rotary shaft 59 so that the toner 57 is shifted to the toner collecting state in contact with the surface of the developing roller 51 (S22). Then, the control unit executes a toner collecting operation to be described later (S23), moves the accumulated toner on the inlet seal 57 to the surface of the developing roller 51, collects the toner, and prevents the inlet seal 57 in the toner collecting state from being scattered. The inlet seal holder 58 is rotated by controlling the rotation of the rotary shaft 59 so as to return to. Thereafter, all the values D _{1 to} D ₈ recorded in the travel distance recording table are reset to zero, and the control B is terminated.

  As described above, the toner collected on the inlet seal 57 is moved to the surface of the developing roller 51 by bringing the inlet seal 57 into the toner recovery state. In many cases, it is a poorly charged toner such as a weakly charged toner or a reversely charged toner having a low charging capability. For this reason, when the accumulated toner is returned to the developing device and used again for development, there is a possibility that the toner becomes floating toner again in the developing region and accumulates on the inlet seal 57. Therefore, in the present embodiment, the toner moved from the inlet seal 57 to the surface of the developing roller 51 is not collected to the developing device but is discharged to the surface of the photosensitive drum 1 and is discharged to the photosensitive member cleaning device 2. In addition, the belt cleaning device 10 is used for collection.

  Specifically, during the non-image forming operation period, the control unit executes a toner collecting operation. First, in the same manner as a normal image forming operation, the charging device 4 and the exposure unit 7 perform the operation of the photosensitive drum 1. An electrostatic latent image for a solid image is formed on the surface as a toner discharge latent image. On the other hand, the control unit operates the developing device 5 in the same manner as a normal image forming operation and controls the rotation operation of the rotation shaft 59 to shift the inlet seal 57 from the scattering prevention state to the toner recovery state. As a result, the tip of the inlet seal 57 comes into contact with the surface of the developing roller 51, and the toner deposited on the inlet seal 57 is collected in the magnetic brush on the surface of the developing roller 51. The accumulated toner collected in the magnetic brush on the surface of the developing roller 51 in this way adheres to the solid image latent image formed on the surface of the photosensitive drum 1 when passing through the developing region. The toner is discharged onto the surface of the photosensitive drum 1.

  The accumulated toner discharged on the surface of the photosensitive drum 1 in this way then passes through the primary transfer area facing the intermediate transfer belt 8. At this time, a primary transfer bias may be applied so that toner deposited on the surface of the photosensitive drum 1 is primarily transferred to the intermediate transfer belt 8 and collected by the belt cleaning device 10. Alternatively, such a primary transfer bias is not applied, or a bias having a polarity opposite to that of the primary transfer bias is applied, and the deposited toner is passed through the primary transfer region while being maintained on the surface of the photosensitive drum 1. In this manner, the photoconductor cleaning device 2 may collect the data.

  Further, for example, the charging bias and the development bias are set so that the toner moves to the photosensitive drum 1 without performing the exposure process by the exposure unit 7, and the accumulated toner on the developing roller 51 is transferred to the surface of the photosensitive drum 1. You may make it discharge | emit to.

[Embodiment 2]
Next, another embodiment in which the developing device according to the present invention is applied to the same printer as in the first embodiment (hereinafter, this embodiment is referred to as “second embodiment”) will be described with reference to the drawings. To do.
The image forming apparatus according to the second exemplary embodiment is the same as the first exemplary embodiment except that the configuration for preventing toner scattering in the developing device is different. Therefore, the following description will focus on the differences from the first exemplary embodiment. To do.

FIGS. 13 and 14 are schematic diagrams illustrating a toner scattering prevention configuration according to the second exemplary embodiment.
In the second embodiment, in addition to the inlet seal 57, the second inlet seal 57, which is another flexible seal member, is arranged in the inlet seal holder 58 of the first embodiment. The inlet seal 57 according to the second embodiment does not need to be configured so that the movable portion 70 is provided and the position of the tip portion can extend as in the first embodiment.

  The second embodiment is different from the first embodiment in that the inlet seal holder 58 is rotated to switch the inlet seal 57 between a scattering prevention state and a toner or a transfer state. Specifically, in the second embodiment, the rotating shaft 59 is a non-rotating fixed shaft, and the inlet seal holder 58 is rotatably supported by the rotating shaft 59. The inlet seal holder 58 is urged in a direction to rotate in a direction in which the tip of the inlet seal 57 abuts against the surface of the developing roller 51 by a spring as an urging means (not shown). A cam surface of a cam 68 is in contact with the other end of the inlet seal holder 58 (the end opposite to the one end holding the inlet seal 57). The cam 68 is rotated to rotate the inlet seal holder 58. Is rotated in a direction against the urging force of the spring, as shown in FIG. 13, a scattering prevention state in which the front end portion of the inlet seal 57 contacts the surface of the photosensitive drum 1 can be achieved. On the other hand, when the cam 68 is rotated so that the inlet seal holder 58 can be rotated by the biasing force of the spring, the toner collection state in which the tip of the inlet seal 57 contacts the surface of the developing roller 51 as shown in FIG. Can be. In this configuration, by controlling the rotation of the cam 68, the inlet seal 57 can be switched between a scattering prevention state and a toner recovery state.

  In the second embodiment, as in the first embodiment, the rotation of the rotary shaft 59 may be controlled to switch the inlet seal 57 between the scattering prevention state and the toner collection state.

  In the second embodiment, the tip of the second inlet seal 57 provided on the inlet seal holder 58 contacts and separates from the surface of the photosensitive drum 1 in conjunction with the rotation of the inlet seal holder 58. Specifically, as shown in FIG. 13, when the inlet seal holder 58 is positioned at a rotational position where the inlet seal 57 is prevented from being scattered, the tip of the second inlet seal 57 is the surface of the photosensitive drum 1. It will be in the state separated from. On the other hand, as shown in FIG. 14, when the inlet seal holder 58 is positioned at the rotational position where the inlet seal 57 is in the toner recovery state, the tip of the second inlet seal 57 contacts the surface of the photosensitive drum 1. It will be in the state.

  With such a configuration, when at least the inlet seal 57 is in the toner recovery state, the tip of the second inlet seal 57 abuts on the surface of the photosensitive drum 1 to close the gap between the photosensitive drum surface and the developing case. It is possible to suppress the scattering of toner to the outside of the developing device. As a result, even when the inlet seal 57 is in the toner recovery state, even if the toner spills over the tip of the inlet seal 57, it can be received by the second inlet seal 57 and scattered outside the developing device. Can be prevented.

  In particular, in the second embodiment, the deposited toner moved to the developing roller 51 is discharged to the surface of the photosensitive drum 1 in the developing region in a state where the inlet seal 57 is in the toner collecting state, as in the above-described embodiment. And collect. At this time, since the accumulated toner is often a poorly charged toner, it floats without adhering to the surface of the photosensitive drum 1 in the developing region, and the tip of the inlet seal 57 and the surface of the photosensitive drum 1 are floated. A lot of toner falls through. In the second embodiment, it is possible to prevent the toner that falls in this way from being received by the second inlet seal 57 and scatter to the outside of the developing device. Therefore, the accumulated toner on the inlet seal 57 is discharged to the surface of the photosensitive drum 1. Even if a configuration for collecting the toner is used, toner scattering at the time of discharging does not become a problem.

[Modification 1]
Next, a modified example (hereinafter, this modified example is referred to as “modified example 1”) of the configuration for preventing toner scattering in the second embodiment will be described.
FIGS. 15 and 16 are schematic diagrams showing a toner scattering prevention configuration in the first modification.
The second inlet seal 57 in the first modification is supported by a second inlet seal holder 58 supported by a developing case (more specifically, a doctor blade 52 supported by the developing case), and a tip portion thereof is a photosensitive drum. It is the structure which always contacts the surface of 1. In this configuration, not only when the inlet seal 57 is in the toner recovery state but also when the inlet seal 57 is in the scattering prevention state, the tip of the second inlet seal 57 contacts the surface of the photosensitive drum 1. The toner can be prevented from scattering outside the developing device by closing the gap between the surface of the photosensitive drum and the developing case. Even in such a configuration, even when the inlet seal 57 is in the toner recovery state, even if the toner spills over the tip of the inlet seal 57, it can be received by the second inlet seal 57, and the toner is discharged to the outside of the developing device. It can be prevented from scattering. Further, toner scattering when the toner deposited on the inlet seal 57 is discharged onto the surface of the photosensitive drum 1 can be prevented.

[Modification 2]
Next, a modified example of the first embodiment (hereinafter referred to as “modified example 2”) will be described.
In the second modification, the drive control of the developing roller 51 when the inlet seal 57 is in the toner recovery state is different from that in the first embodiment, but the toner scattering prevention configuration is the same as in the first embodiment. Therefore, the following description will focus on the driving control of the developing roller 51 in the toner recovery state.
The second modification can also be applied to the toner scattering prevention configuration of the second embodiment (including the first modification).

FIGS. 19A and 19B are explanatory views showing the state of the toner when the developing roller 51 is rotationally driven in the same direction as in the image forming operation when the entrance seal 57 is shifted to the toner collecting state.
As shown in FIG. 19A, when the entrance seal 57 is shifted to the toner collecting state, when the developing roller 51 is driven to rotate in the same direction as in the image forming operation, the front end portion of the entrance seal 57 and the developing roller 51 The surface of the developing roller 51 moves toward the outside of the developing case (in the direction of arrow B in the figure, hereinafter referred to as “forward direction”). In this case, a part of the toner accumulated on the inlet seal 66 is carried on the surface of the developing roller 51 and conveyed outside the developing case as shown in FIG. Here, most of the toner deposited on the inlet seal 66 is toner that floats in the development region, and is poorly charged toner such as weakly charged toner or reversely charged toner with low charging ability. Therefore, when the toner is carried on the surface of the developing roller 51 and transported to the outside of the developing case, the toner easily separates from the surface of the developing roller 51 as toner indicated by reference numeral T4 in FIG. May be contaminated or an abnormal image may be generated.

  Therefore, in the second modification, when the inlet seal 57 is in the toner recovery state, as shown in FIGS. 20A and 20B, the developing roller 51 is rotationally driven in the direction opposite to that during the image forming operation. Thus, the rotation of the developing roller 51 is controlled. More specifically, when the inlet seal 57 is in a toner recovery state, the developing case 51 is directed toward the inside of the developing case at the contact portion between the tip of the inlet seal 57 and the developing roller 51 (FIG. 20). The rotation of the developing roller 51 is controlled so as to move in the direction of the middle arrow C (hereinafter referred to as “reverse direction”). By performing such control, even if a part of the toner accumulated on the inlet seal 66 is carried on the surface of the developing roller 51 as shown in FIG. As a result, it is possible to suppress the occurrence of in-machine contamination and abnormal images without being scattered toner.

  The timing for starting the rotation driving of the developing roller 51 in the reverse direction may be before or after the entrance seal 57 shifts to the toner recovery state. However, when starting to rotate the developing roller 51 in the reverse direction after the entrance seal 57 shifts to the toner recovery state, the developing roller 51 is driven to rotate in the reverse direction after shifting to the toner recovery state of the entrance seal 57. It is preferable to prevent the forward rotation of the developing roller 51 from entering before. This is because the toner on the entrance seal 66 is most likely to be carried on the surface of the developing roller 51 immediately after the entrance seal 57 shifts to the toner recovery state.

  In the second modification, the toner recovery timing for shifting the inlet seal 57 from the scattering prevention state to the toner recovery state has arrived, and almost simultaneously with the transition of the inlet seal 57 in the scattering prevention state to the toner recovery state, Reverse rotation driving is started. Thus, immediately after the entrance seal 57 shifts to the toner collection state, the toner on the entrance seal 66 can be gradually carried on the surface of the developing roller 51 that is driven to rotate in the reverse direction and collected in the developing case.

  In particular, in the second modification, the developer on the developing roller 51 rises by the magnetic force of a magnet fixed inside the developing roller 51, and the toner on the entrance seal 66 is scraped off by the raised developer. As a result, the toner on the inlet seal 66 is carried on the developing roller 51. By collecting the toner on the inlet seal 66 by using the developer that has risen in this manner, the toner on the inlet seal 66 can be collected more efficiently.

  At this time, since the rising state of the developer on the developing roller 51 varies depending on the rotation direction of the developing roller 51, the way the toner on the inlet seal 66 is scraped varies depending on the rotation direction of the developing roller 51. Therefore, if the rotation direction of the developing roller 51 is switched between the forward direction and the reverse direction when the inlet seal 57 shifts to the toner collecting state, the toner collecting effect on the inlet seal 66 can be enhanced.

  In the second modification, the operation of rotating the developing roller 51 in the reverse direction for a predetermined time and then rotating the developing roller 51 in the forward direction for a predetermined time is defined as one recovery operation. Change according to environment and mileage. That is, as the number of collection operations increases, the toner collection effect on the inlet seal 57 is higher, but there is also a problem that the time required for the toner collection becomes longer. Therefore, it is preferable to change the number of collection operations according to the amount of toner accumulated on the input seal 57. As described above, the amount of toner deposited on the input seal 57 varies depending on the image area ratio, environment, and travel distance. Therefore, the toner on the inlet seal 57 can be properly recovered by changing the number of recovery operations according to the image area ratio, environment, and travel distance as in the second modification.

FIG. 21 is an explanatory diagram for explaining the contents of the collection operation number determination table recorded in the recording means accessible by the control unit of the copying machine in the second modification.
As shown in FIG. 21, the collection operation frequency determination table is divided into two, with the image area ratio, the environment, and the travel distance, respectively, with A ₀ , H ₀ , and D ₀ as boundaries, as in the travel distance recording table described above. Yes. When the toner recovery timing for shifting the inlet seal 57 from the scattering prevention state to the toner recovery state has arrived, the control unit according to the second modification has the current developing device travel distance D and the image area ratio from the previous execution of the control. Three pieces of information (average image area ratio) A and the current absolute humidity H are acquired, and based on these pieces of information, it is determined which of the eight categories in the collection operation number determination table corresponds. And the collection | recovery operation | movement mentioned above is performed as many times as set to the determined division.

For example, consider a case where the image area ratio is A <A ₀ , the absolute humidity is H ≧ H ₀ , and the developing device travel distance is D <D ₀ . In this case, first, a classification that satisfies the condition that the image area ratio is A <A ₀ and the developing device travel distance is D <D ₀ is identified from the collection operation frequency determination table shown in FIG. The number of collection operations (one time) corresponding to the category is specified. Next, a category that satisfies the condition that the absolute humidity is H ≧ H ₀ and the developing device travel distance is D <D ₀ is identified from the collection operation frequency determination table shown in FIG. 21 and corresponds to this category. The number of collection operations to be performed (3 times) is specified. Then, the number of times of the specified collecting operation is determined as the number of collecting operations this time.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A developing case containing developer G containing toner, a developer carrying member such as a developing roller 51 carrying the developer on the surface and moving on the surface, and a latent image carrying the leading end of the photosensitive drum 1 or the like A flexible seal member such as an inlet seal 57 that closes the gap between the surface of the latent image carrier and the developing case by contacting the surface of the body and suppresses toner from being scattered outside the developing device; And the flexible seal member is configured so that the tip portion selectively contacts the surface of the latent image carrier or the surface of the developer carrier with the tip portion facing upward. In the developing device 5 in which the end opposite to the tip is supported by the developing case so as to be movable, the flexible seal member has the tip on the surface of the latent image carrier. The toner that contacts the surface of the developer carrier from the contact scattering prevention state. Wherein the position of the tip portion is configured to extend when moving to over recovery state.
According to this, when the inlet seal 57 is switched from the scattering prevention state to the toner recovery state, the accumulated toner on the inlet seal 57 gets over the front end portion of the inlet seal 57 and the front end portion of the inlet seal 57 and the photosensitive drum 1 are in contact with each other. Leakage from the gap between them can be suppressed. Thereby, it is possible to prevent the toner leaking in this way from being scattered outside the developing device.

(Aspect B)
In the above aspect A, when the flexible seal member is in a toner recovery state in which the tip end portion is brought into contact with the surface of the developer carrying member, the tip portion comes into contact with the surface of the latent image carrying member. It has another flexible seal member such as a second inlet seal 57 that closes a gap between the surface of the latent image carrier and the developing case and suppresses the toner from scattering to the outside of the developing device.
According to this, at least when the flexible seal member is in the toner recovery state, the tip of another flexible seal member comes into contact with the surface of the latent image carrier and the gap between the surface of the latent image carrier and the developing case. The toner can be prevented from being scattered outside the developing device. As a result, even if the toner spills over the tip of the flexible seal member when the flexible seal member is in the toner recovery state, it is scattered to the outside of the developing device by another flexible seal member. Can be prevented.

(Aspect C)
In the above aspect B, in conjunction with the movement of the flexible seal member from the scattering prevention state to the toner recovery state, the other flexible seal member has its tip portion on the surface of the latent image carrier. It is configured to move from a state separated from the surface to a state in which the latent image carrier is in contact with the surface of the latent image carrier.
According to this, in order to suppress the occurrence of defects such as image quality degradation due to the tip portion of another flexible seal member being in contact with the surface of the latent image carrier, A configuration in which the tip is brought into contact with and separated from the surface of the latent image carrier can be easily realized.

(Aspect D)
A developer case containing a developer containing toner, a developer carrier that carries the developer on the surface and moves, and a latent image carrier that has a tip abutting against the surface of the latent image carrier A flexible seal member that closes a gap between the surface of the body and the developing case and prevents the toner from scattering to the outside of the developing device, and the distal end of the flexible seal member faces upward. The end on the opposite side of the tip is positioned so that the tip can be moved so as to selectively contact the surface of the latent image carrier or the surface of the developer carrier in the state of facing. In the developing device supported by the developing case, when the flexible seal member is in a toner recovery state in which the tip is in contact with the surface of the developer carrier, the tip is the latent image carrier. By contacting the surface, the surface of the latent image carrier and the developing case Wherein the blocking between the developing device outside the toner has a different flexible sealing member inhibits from dispersing.
According to this, at least when the flexible seal member is in the toner recovery state, the tip of another flexible seal member comes into contact with the surface of the latent image carrier and the gap between the surface of the latent image carrier and the developing case. The toner can be prevented from being scattered outside the developing device. As a result, even if the toner spills over the tip of the flexible seal member when the flexible seal member is in the toner recovery state, it is scattered to the outside of the developing device by another flexible seal member. Can be prevented.

(Aspect E)
In any one of the above aspects A to D, toner collection timing control means such as a control unit for controlling the timing of switching the flexible seal member from the scattering prevention state to the toner collection state according to a predetermined toner collection timing It is characterized by having.
According to this, it is possible to move the deposited toner to the surface of the developer carrying member with an appropriate frequency before the toner deposited on the flexible seal member exceeds the allowable amount. Therefore, by appropriately setting the toner recovery timing, the toner accumulated on the flexible seal member is allowed to be switched without excessively switching between the scattering prevention state and the toner recovery state of the flexible seal member. Occurrence of a situation in which the accumulated toner is scattered beyond the capacity can be suppressed.

(Aspect F)
In the aspect E, there is provided toner consumption index value storage means for storing a toner consumption index value such as an image area ratio indicating a toner amount consumed by an image forming operation in a past predetermined period, and the toner collection timing The control means changes the predetermined toner collection timing in accordance with a toner consumption index value stored in the toner consumption index value storage.
According to this, even when the toner consumption amount in the developing device is large and the insufficiently charged toner is transported to the developing region, the toner accumulated on the flexible seal member has not exceeded the allowable amount. The deposited toner can be moved to the surface of the developer carrying member at an appropriate timing.

(Aspect G)
In the aspect E or F, there is provided environmental information acquisition means such as a temperature / humidity sensor for acquiring environmental information including at least one of temperature and humidity, and the toner collection timing control means is the environment acquired by the environmental information acquisition means. The predetermined toner collection timing is changed according to the information.
According to this, even if the toner with insufficient charge amount is easily transported to the development area depending on the use environment, the toner deposited on the flexible seal member is appropriately timed before it exceeds the allowable amount. Can be moved to the surface of the developer carrying member.

(Aspect H)
In any one of the above aspects E to G, the developer is a two-component developer including a toner and a carrier, and carrier deterioration index value storage means for storing a carrier deterioration index value indicating a deterioration state of the carrier. And the toner recovery timing control means changes the predetermined toner recovery timing in accordance with the carrier deterioration index value stored in the carrier deterioration index value storage means.
According to this, even in a situation where the carrier in the developing device is deteriorated and the insufficiently charged toner is conveyed to the developing area, the toner accumulated on the flexible seal member can be appropriately used before exceeding the allowable amount. It is possible to move the deposited toner to the surface of the developer carrying member at an appropriate timing.

(Aspect I)
In any one of the above aspects A to H, when the flexible seal member is in the toner recovery state, the contact portion between the tip of the flexible seal member and the developer carrying member It has toner recovery drive control means such as a controller for moving the surface of the developer carrying member so that the surface of the developer carrying member moves in the developing case internal direction (reverse direction) toward the inside of the developing case. .
According to this, when the flexible seal member is switched to the toner recovery state, the accumulated toner on the flexible seal member is carried on the surface of the developer carrying member and conveyed to the outside of the developing case. It can suppress scattering.

(Aspect J)
In the aspect I, the toner recovery drive control means moves the developer carrying member to the inside of the developing case at least once when the flexible seal member is in the toner recovery state. And
According to this, when the flexible seal member is switched to the toner recovery state, it is possible to stably suppress the toner deposited on the flexible seal member from scattering outside the developing case.

(Aspect K)
In the above aspect I or J, the toner recovery drive control means develops the direction in which the surface of the developer carrying member moves at the contact portion when the flexible seal member is in the toner recovery state. The developing case is switched between the direction outside the developing case (forward direction) and the direction inside the developing case.
According to this, the recovery efficiency of the toner deposited on the flexible seal member in the toner recovery state can be improved as compared with the case where the surface of the developer carrying member is moved only in one direction. it can.

(Aspect L)
In the aspect K, the toner recovery drive control unit controls the first developer carrier surface movement direction when the flexible seal member is in the toner recovery state to be the internal direction of the developing case. It is characterized by that.
According to this, when the flexible seal member is switched to the toner recovery state, the accumulated toner on the flexible seal member is carried on the surface of the developer carrying member that moves to the outside of the developing case, The situation of scattering outside the developing case can be suppressed.

(Aspect M)
In the aspect K or L, the toner consumption index value storage means for storing a toner consumption index value such as an image area ratio indicating a toner amount consumed by an image forming operation in a past predetermined period, and the toner The collection drive control unit is configured to store a toner consumption index value storage unit that stores the number of times the developer carrying member is moved in the surface movement direction when the flexible seal member is in the toner collection state. It changes according to a consumption index value.
According to this, even when the toner consumption amount in the developing device is large and the insufficiently charged toner is conveyed to the developing region, the toner deposited on the flexible seal member can be appropriately collected. it can.

(Aspect N)
In any one of the above aspects K to M, the apparatus has an environmental information acquisition unit such as a temperature / humidity sensor that acquires environmental information including at least one of temperature and humidity. The number of times the developer carrying member is moved in the surface moving direction when the seal member is in the toner collecting state is changed according to the environmental information acquired by the environmental information acquiring unit.
According to this, even if the toner with insufficient charge amount is easily conveyed to the development area depending on the use environment, the toner deposited on the flexible seal member can be properly collected.

(Aspect O)
In any one of the above aspects K to N, the developer is a two-component developer including a toner and a carrier, and carrier deterioration index value storage means for storing a carrier deterioration index value indicating a deterioration state of the carrier. And the toner recovery drive control means stores, in the carrier deterioration index value storage means, the number of times the developer carrying member is switched in the surface movement direction when the flexible seal member is in the toner recovery state. The carrier deterioration index value is changed according to the value.
According to this, even when the carrier in the developing device is deteriorated and the insufficiently charged toner is conveyed to the developing region, the toner deposited on the flexible seal member can be properly collected. .

(Aspect P)
In the image forming apparatus for finally transferring a toner image obtained by developing a latent image formed on a latent image carrier with toner with a developing device to a recording material to form an image on the recording material, the developing device As described above, the developing device according to any one of the above aspects A to O is used.
According to this, an image forming apparatus with less toner scattering can be provided.

(Aspect Q)
In the image forming apparatus for finally transferring a toner image obtained by developing a latent image formed on a latent image carrier with toner with a developing device to a recording material to form an image on the recording material, the developing device As described above, when the developing device according to any one of aspects A to H is used and the flexible seal member is in the toner recovery state, a predetermined toner discharge latent image is formed on the latent image carrier. At the same time, the developer carrying member is moved so that the surface of the developer carrying member moves from the inside of the developing case toward the developing region at the contact portion between the tip of the flexible seal member and the developer carrying member. And a control unit such as a control unit that executes a toner discharging operation for developing the toner discharging latent image in the developing region.
According to this, since the toner deposited on the flexible seal member contains a large amount of poorly charged toner, such deposited toner can be discharged and collected on the surface of the latent image carrier. Further, the chance that the poorly charged toner contributes to the development again can be reduced, and toner scattering can be further suppressed.

(Aspect R)
At least a latent image carrier and a developing device that develops the latent image formed on the latent image carrier with toner are supported on a common support and are integrally attached to and detached from the image forming apparatus main body. In a freely configured process cartridge, the developing device according to any one of the above aspects A to O is used as the developing device.
According to this, a process cartridge with less toner scattering can be provided.

DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Photoconductor cleaning device 4 Charging device 5 Developing device 6 Image forming unit 7 Exposure unit 8 Intermediate transfer belt 10 Belt cleaning device 20 Fixing unit 51 Developing roller 52 Doctor blades 53 and 54 Developer container 57 Entrance seal 58 Entrance seal holder 59 Rotating shaft 66 Entrance seal 67 Entrance seal holder 68 Cam 70 Movable part 71 Projection part 100 Printer

Japanese Patent No. 3492858 JP 10-307474 A JP 2012-118359 A

Claims (18)

A developing case containing a developer containing toner therein;
A developer carrying body carrying the developer on the surface and moving on the surface;
A flexible seal member that closes a gap between the surface of the latent image carrier and the developing case by abutting the front end portion against the surface of the latent image carrier and suppresses toner from being scattered outside the developing device; Have
The flexible seal member is movable so that the tip portion thereof is selectively brought into contact with the surface of the latent image carrier or the surface of the developer carrier with the tip portion thereof facing upward. In the developing device in which the end opposite to the tip is supported by the developing case,
When the flexible seal member moves from a scattering prevention state in which the front end portion thereof contacts the surface of the latent image carrier to a toner recovery state in which the front end portion contacts the surface of the developer carrier, the position of the front end portion is changed. A developing device configured to extend. The developing device according to claim 1.
When the flexible seal member is in a toner recovery state in which the front end portion is in contact with the surface of the developer carrying member, the front end portion is brought into contact with the surface of the latent image carrying member, thereby A developing device comprising another flexible sealing member that blocks a gap between the surface and the developing case and prevents toner from scattering outside the developing device. The developing device according to claim 2.
In conjunction with the movement of the flexible seal member from the scattering prevention state to the toner recovery state, the other flexible seal member is moved from the state in which the distal end portion thereof is separated from the surface of the latent image carrier. A developing device configured to move to a state in which the latent image carrier is in contact with the surface of the latent image carrier. A developing case containing a developer containing toner therein;
A developer carrying body carrying the developer on the surface and moving on the surface;
A flexible seal member that closes a gap between the surface of the latent image carrier and the developing case by abutting the front end portion against the surface of the latent image carrier and suppresses toner from being scattered outside the developing device; Have
The flexible seal member is movable so that the tip portion thereof is selectively brought into contact with the surface of the latent image carrier or the surface of the developer carrier with the tip portion thereof facing upward. In the developing device in which the end opposite to the tip is supported by the developing case,
When the flexible seal member is in a toner recovery state in which the front end portion is in contact with the surface of the developer carrying member, the front end portion is brought into contact with the surface of the latent image carrying member, thereby A developing device comprising another flexible sealing member that blocks a gap between the surface and the developing case and prevents toner from scattering outside the developing device. The developing device according to any one of claims 1 to 4,
According to a predetermined toner collecting timing, the flexible seal member, a toner collecting timing control means for the distal end to control the timing of switching from splashing prevention state in contact with the surface of the latent image carrier to the toner recovery state A developing device comprising: The developing device according to claim 5.
A toner consumption index value storage means for storing a toner consumption index value indicating the amount of toner consumed by an image forming operation in a past predetermined period;
The developing device according to claim 1, wherein the toner collection timing control means changes the predetermined toner collection timing in accordance with a toner consumption index value stored in the toner consumption index value storage. The developing device according to claim 5 or 6,
Having environmental information acquisition means for acquiring environmental information including at least one of temperature and humidity;
The developing device according to claim 1, wherein the toner collection timing control unit changes the predetermined toner collection timing in accordance with the environmental information acquired by the environmental information acquisition unit. The developing device according to any one of claims 5 to 7,
The developer is a two-component developer containing a toner and a carrier;
Carrier deterioration index value storage means for storing a carrier deterioration index value indicating the deterioration state of the carrier,
The developing device according to claim 1, wherein the toner recovery timing control means changes the predetermined toner recovery timing in accordance with a carrier deterioration index value stored in the carrier deterioration index value storage means. The developing device according to any one of claims 1 to 8,
When the flexible seal member is in the toner collection state, the surface of the developer carrying member faces the inside of the developing case at the contact portion between the tip of the flexible seal member and the developer carrying member. A developing device comprising toner recovery drive control means for moving the surface of the developer carrying member so as to move toward the inside of the developing case. The developing device according to claim 9.
The developing device according to claim 1, wherein the toner collection drive control means moves the surface of the developer carrying member toward the inside of the developing case at least once when the flexible seal member is in the toner collecting state. The developing device according to claim 9 or 10,
The toner recovery drive control means is configured to adjust the direction in which the surface of the developer carrying member moves at the contact portion to the outside of the development case when the flexible seal member is in the toner recovery state. A developing device that switches between a direction and a direction inside the developing case. The developing device according to claim 11.
The toner recovery drive control means controls the first developer carrier surface movement direction when the flexible seal member is in the toner recovery state to be the internal direction of the developing case. Development device. The image forming apparatus according to claim 11 or 12,
A toner consumption index value storage means for storing a toner consumption index value indicating the amount of toner consumed by an image forming operation in a past predetermined period;
The toner recovery drive control means stores in the toner consumption index value storage means the number of times the developer carrying member is moved in the surface movement direction when the flexible seal member is in the toner recovery state. The developing device is changed according to the toner consumption index value. The developing device according to any one of claims 11 to 13,
Having environmental information acquisition means for acquiring environmental information including at least one of temperature and humidity;
The toner collection drive control means determines the number of times of switching of the surface movement direction of the developer carrier performed when the flexible seal member is in the toner collection state according to the environment information acquired by the environment information acquisition means. The developing device is characterized by being changed. The developing device according to any one of claims 11 to 14,
The developer is a two-component developer containing a toner and a carrier;
Carrier deterioration index value storage means for storing a carrier deterioration index value indicating the deterioration state of the carrier,
The toner recovery drive control means stores, in the carrier deterioration index value storage means, the number of times of change in the surface movement direction of the developer carrier performed when the flexible seal member is in the toner recovery state. A developing device that changes according to a carrier deterioration index value. In an image forming apparatus for finally transferring a toner image obtained by developing a latent image formed on a latent image carrier with toner by a developing device to a recording material to form an image on the recording material,
An image forming apparatus using the developing device according to claim 1 as the developing device. In an image forming apparatus for finally transferring a toner image obtained by developing a latent image formed on a latent image carrier with toner by a developing device to a recording material to form an image on the recording material,
As the developing device, using the developing device according to any one of claims 1 to 8,
When the flexible seal member is in the toner collection state, a predetermined toner discharge latent image is formed on the latent image carrier, and the tip of the flexible seal member, the developer carrier, The developer carrying member is moved so that the surface of the developer carrying member moves from the inside of the developing case toward the developing region at the abutting portion, and the toner discharge for developing the toner discharging latent image in the developing region is performed. An image forming apparatus comprising control means for executing an operation. At least a latent image carrier and a developing device that develops the latent image formed on the latent image carrier with toner are supported on a common support and are integrally attached to and detached from the image forming apparatus main body. In a freely configured process cartridge,
16. A process cartridge using the developing device according to claim 1 as the developing device.

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