JP2017191209A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply toner to a surface of a developing roller with a simple configuration despite a configuration using a non-magnetic one-component toner and not including a supply roller.SOLUTION: An image forming apparatus stops toner conveyance means arranged in the vicinity of a developing roller during an image forming period to form good circulation of toner and accumulation of toner in the vicinity of the developing roller. The image forming apparatus rotates the toner conveyance means in a non-image forming period to loosen the toner and refreshes the state of the accumulation of toner formed in the vicinity of the developing roller.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an image forming apparatus such as an electrophotographic printer or an electrophotographic copying machine.

  One of image forming methods used in image forming apparatuses such as copying machines is an electrophotographic recording method. In this method, the surface of the photosensitive drum as an image carrier is uniformly charged by a charging device, an electrostatic latent image is formed by an exposure device, and the toner as a developer is formed by a developing device, and the electrostatic latent image is converted into a toner image. To visualize. The toner image is transferred to a recording material such as paper via a transfer device such as an intermediate transfer member, and finally fixed by a fixing device. On the other hand, the remaining toner that could not be transferred from the photosensitive drum to the transfer target is collected by a cleaning device that is in contact with the photosensitive drum.

As a developing device, non-magnetic one-component toner contained in a developing container is supplied to a developing roller as a developer carrying member by a supply roller, and the toner thickness on the developing roller is substantially constant by a developing blade as a developer regulating member. There is a method of developing an electrostatic latent image (Patent Document 1).
A developing device that uses a non-magnetic one-component toner but does not use a supply roller has also been proposed. According to this configuration, the supply guide that contacts the developing roller is provided, and the toner is conveyed and collected in the space formed by the developing roller and the supply guide, and the toner is supplied by the synergistic effect of the toner weight and the rotational force of the developing roller. (Patent Document 2).

  Further, as a developing roller, there has been proposed a method in which portions having different resistances or dielectric constants are regularly exposed and mixed at a constant pattern pitch on the surface to form a large number of minute electric fields on the surface. By using this method, an appropriate amount of toner can be attached to the electrostatic latent image on the photosensitive drum, so that an image with high image density and excellent line reproducibility and gradation can be obtained. (Patent Document 3).

JP-A-6-43745 JP-A-8-44206 JP-A-6-130792

  However, the method using the supply roller requires a mechanism for rotating the supply roller in addition to the developer carrier, and the supply roller itself is limited in size. It becomes difficult.

  On the other hand, in the method using no supply roller, the above-described problems are reduced, but it is difficult to stably supply the developer to the developer carrying member.

  That is, when the pressure of the developer on the surface of the developer carrier is insufficient, the developer necessary for image formation may not be sufficiently carried on the developer carrier.

  On the other hand, even when the pressure of the developer on the developer carrying member is too high, the aggregate developer is likely to be generated in the vicinity of the developer carrying member. Since this aggregated developer hinders the supply of the developer to the developer carrier, the developer may not be sufficiently carried on the developer carrier.

  The present invention has been intensively studied in order to solve the above-mentioned problems, and stably supplies the developer to the developer carrier while having a configuration in which the developer is simply supplied to the developer carrier. An object of the present invention is to provide a developing device that can be used.

In order to achieve the above object, the invention according to the present application is
Developer,
A developer container containing the developer;
A developer carrying member rotatably supported by the developing container and carrying the developer;
A transport member that is provided inside the developer container and includes a shaft portion and a transport portion connected to the shaft portion, and transports the developer;
A developing device used in an image forming apparatus including:
A regulation part for regulating the developer carried on the developer carrying body;
The regulating portion is a region around the developer carrier,
In the region where the surface of the developer carrier moves upward in the direction of gravity during image formation,
Arranged to face the developer carrier,
The conveying member stops at least at a part during image formation and takes a stop posture;
When the transport member is in the stop position,
The amount of the developer carried on the developer carrier is:
The developing device is characterized in that the carrying amount is larger than the carrying amount when the conveying member takes a posture different from the stopping posture.

  According to the present invention, the developing device includes the regulating unit and the conveying member that conveys the developer, and the conveying member stops during image formation. Accordingly, the developer member necessary for the developer carrying member to carry the developer can be formed by the conveying member, and an appropriate developer pressure can be applied to the developer carrying member. Moreover, it can suppress that the pressure of the developer with respect to a developing agent carrier becomes excess by a conveyance member. Therefore, the developer can be stably supplied to the development carrier.

1 is a diagram illustrating an image forming apparatus according to a first exemplary embodiment. FIG. 4 is a diagram illustrating a developing device according to the first embodiment. FIG. 6 is a diagram illustrating toner carrying of the developing roller according to the first exemplary embodiment. FIG. 6 is a diagram illustrating toner carrying of the developing roller according to the first exemplary embodiment. FIG. 6 is a diagram illustrating the arrangement of the developing roller, the developing blade, and the toner conveying member according to the first embodiment. FIG. 6 is a diagram illustrating the arrangement of the developing roller, the developing blade, and the toner conveying member according to the first embodiment. FIG. 6 is a diagram illustrating an arrangement of a developing roller, a regulation unit, and a toner conveying member according to the first exemplary embodiment. FIG. 6 is a diagram illustrating rotation and stop operations of the toner conveying member according to the first exemplary embodiment. FIG. 6 is a diagram illustrating a stopping posture of the toner conveying member according to the first exemplary embodiment. FIG. 6 is a diagram illustrating a reason for rotating a toner conveying member during non-image formation according to the first exemplary embodiment. FIG. 6 is a diagram illustrating an example of a configuration for stopping a toner conveying member according to the first exemplary embodiment. The figure explaining the developing roller used in Example 2 FIG. 6 is a diagram illustrating an image forming apparatus used in Embodiment 3. FIG. 6 is a diagram for explaining the operation of a toner conveying unit in Embodiment 3. The figure explaining operation | movement of the rocking | swiveling member in Example 3. FIG. 6 is a diagram illustrating an image forming apparatus according to a fourth embodiment. FIG. 6 is a diagram illustrating a toner conveying member in Embodiment 4. FIG. 6 is a diagram illustrating a process cartridge according to a fifth embodiment.

[Example 1]
Hereinafter, the form of a present Example is illustrated with reference to drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment should be changed as appropriate according to the configuration of the apparatus to which the present invention is applied and various conditions. It is not intended that the scope of the present invention be limited to the following embodiments.

<Image forming apparatus and process cartridge>
An electrophotographic image forming apparatus (image forming apparatus) such as a copying machine and a printer applied to the first embodiment and a process cartridge that can be attached to and detached from the apparatus will be described with reference to FIG.

  FIG. 1 is a schematic cross-sectional view illustrating the configuration of the image forming apparatus according to the first embodiment. As shown in FIG. 1, the image forming apparatus according to the first embodiment includes a process cartridge 1 in an image forming main body 70 in a detachable manner.

  The process cartridge 1 includes a photosensitive drum 10 as an image carrier that carries an electrostatic latent image, a charging roller 11 as a charging member, a cleaning device 5, and a developing device 3. The developing device 3 has a developing roller 31 as a developer carrying member, and contains a developer (hereinafter referred to as toner) T made of a negatively chargeable nonmagnetic one-component developer. The developing device 3 is configured such that the developing roller 31 can be brought into contact with and separated from the photosensitive drum 10.

  A predetermined DC voltage is applied to the charging roller 11 from charging device voltage applying means 71 provided in the image forming body 70. The charging roller 11 uniformly charges the surface of the photosensitive drum 10.

  The exposure apparatus 2 as an optical unit irradiates the surface of the photosensitive drum 10 with a laser modulated by image information sent from an information processing device (not shown). Then, an electrostatic latent image is formed on the surface of the photosensitive drum 10.

  The developing device voltage applying means 72 applies a predetermined DC voltage to the developing roller 31 in order to make the electrostatic latent image visible by the developing device 3. Then, the developing roller 31 comes into contact with the photosensitive drum 10 and the toner T contained in the developing device 3 is developed on the surface of the photosensitive drum 10 to form a visible image (hereinafter, toner image).

  In synchronization with the formation of the toner image, a recording material P as a recording medium is conveyed from a cassette 76 as a paper feeding unit. In order to transfer the toner image on the photosensitive drum 10 to the recording material P, a predetermined voltage is applied to a transfer roller 75 as a transfer unit by a transfer device voltage applying unit 73.

  Most of the toner image is transferred to the recording material P, but a part of the toner image remains on the photosensitive drum 10. The remaining toner T is collected by the cleaning device 5.

  The fixing device 60 as a fixing unit fixes the toner image transferred onto the recording material P by heat and pressure. The recording material P that has been fixed is discharged onto a paper discharge tray 74.

  Thereafter, image formation is continued by repeating the same process. In the following description, “at the time of image formation” means that the electrostatic latent image formed on the surface of the photosensitive drum 10 based on the image information reaches a position where the photosensitive drum 10 and the developing roller 31 are in contact (developing position). Suppose that the developing device 3 is converting the electrostatic latent image into a toner image. “At the time of non-image formation” is defined as a time when the developing device 3 is not converting the electrostatic latent image into a toner image.

<Developing device>
The configuration of the developing device 3 of this embodiment will be described with reference to FIG. FIG. 2 shows the developing device 3 during image formation.

  The developing device 3 includes a toner T, a developing roller 31, a developing container 32 that accommodates the toner T, a toner conveying member 33 as a conveying member, and a developing blade 34 as a developer regulating member.

  The toner T is non-magnetic negatively chargeable, and for example, a material such as non-magnetic styrene acrylic type + polyester type resin is used.

  The developing roller 31 is for carrying the toner T on the surface, and is disposed in an opening provided below the developing container 32. The developing roller 31 is supported by the developing container 32 so as to be rotatable in the R1 direction with a center axis (not shown) as a rotation center.

  A toner conveying member 33 is provided inside the developing container 32. The toner transport member 33 includes a shaft portion 33a and a transport portion 33b that is connected to the shaft portion 33a and transports the toner T. The shaft portion 33a is made of high impact polystyrene (HIPS) or the like. The conveyance part 33b consists of thin elastic bodies, such as a polyethylene terephthalate (PET) sheet | seat of thickness about 50-200 micrometers. The toner conveying member 33 is rotatable in the direction of the arrow R2, and is rotated so as to convey the toner T located at the lower position in the gravity direction from the center of the shaft portion 33a toward the vicinity of the developing roller 31.

  The developing blade 34 is made of a metal plate such as stainless steel (SUS) having a thickness of 50 to 120 μm. The developing blade 34 contacts the developing roller 31 with a contact pressure of about 10 to 50 gf / cm, thereby regulating the thickness of the toner T on the developing roller 31 to be substantially constant.

  An opening sealing sheet 29 is provided downstream of the developing blade 34 in the rotation direction R1. The opening sealing sheet 29 contacts the developing roller 31 and prevents the toner T inside the developing container 32 from leaking out.

  Here, the surface of the developing roller 31 from the position where the opening sealing sheet 29 is in contact with the developing roller 31 to the position where the developing blade 34 is in contact with the developing roller 31 along the rotation direction R1 is expressed as “ The surface of the developing roller 31 facing the inside of the developing container 32 is defined.

  With this configuration, the developing device 3 regulates the amount of the toner T carried on the developing roller 31 by the developing blade 34 and supplies the toner T to the photosensitive drum 10.

  Before image formation, the developing roller 31 and the photosensitive drum 10 are separated with a gap of about 100 μm. When the image forming signal is sent, the image forming apparatus drives the drive input unit 36 of the developing device 3 by a driving source (not shown), and the developing roller 31 rotates. Subsequently, the developing device 3 moves around the swing center 20 by the contact / separation driving unit 65 (see FIG. 1), and the photosensitive drum 10 and the developing roller 31 come into contact with each other. Then, the developing device 3 performs the above-described toner image formation. In this embodiment, when the developing roller 31 and the photosensitive drum 10 are in contact with each other, the toner conveying member 33 is stopped. That is, the toner conveying member 33 stops at least at a part during image formation. On the other hand, when the two are separated, the toner transport member 33 rotates. The reason for adopting such a mechanism will be described later.

<Toner carrying on developing roller>
The toner carrying of the developing roller 31 will be described with reference to FIGS. FIG. 3 shows the developing roller 31, the toner T, the toner conveying member 33, and the developing blade 34 during image formation. As shown in FIG. 3, in the present embodiment, the developing blade 34 includes a contact portion 34 </ b> N that contacts the developing roller 31 and serves as a restricting portion that restricts the toner T carried on the developing roller 31. The contact portion 34N is disposed so as to face the developing roller 31 in a region where the surface of the developing roller 31 moves upward in the gravity direction during image formation in the region around the developing roller 31. The function of the contact portion 34N will be described later.

  The toner is carried on the developing roller 31 by creating a toner circulation W and a toner reservoir S as shown in FIG. The toner T is conveyed by the force of the developing roller 31 rotating in the R1 direction, and rises above the surface of the developing roller 31. A part of the toner T is regulated by the contact portion 34N of the developing blade 34. The regulated toner T goes to the lower side of the developing container 32. That is, the developing roller 31 returns toward the upstream side in the rotation direction R1. In this way, toner circulation W can be performed. The toner T rising on the developing roller 31 is charged by being rolled in the direction of the arrow R3 on the developing roller 31 by rolling friction with the toner T regulated by the contact portion 34N.

  When the toner T on the developing roller 31 is charged, a minute closed electric field is generated between the charged toner TC and the adjacent developing roller 31 surface, as shown in FIG. A minute closed electric field is formed. At this time, if the toner reservoir S is formed in the vicinity of the developing roller 31, the uncharged toner TD in the toner reservoir S has a gradient force generated by the above-mentioned minute closed electric field (Ueda et al. 15) Receive. The uncharged toner TD in the vicinity of the developing roller 31 is sucked and carried on the surface of the developing roller 31.

<Arrangement of toner conveying member and developing blade>
The arrangement of the toner conveying member 33 and the developing blade 34 will be described in more detail with reference to FIGS.

  FIG. 5 shows the developing device 3 during image formation. As described above, at the time of image formation, the developing roller 31 is rotated and the toner conveying member 33 is stopped. The posture taken by the toner conveying member 33 when the toner conveying member 33 is stopped during image formation is referred to as a stopped posture.

  As shown in FIG. 5, the developing roller 31 is divided into four quadrants (81, 82, 83, 84) by drawing the straight line in the gravity direction and the horizontal direction passing through the rotation center O with the rotation center O of the developing roller 31 as the origin. To do. The center L of the shaft portion 33a of the toner conveying member 33 and the contact portion 34N of the developing blade 34 are such that the surface of the developing roller 31 in the region around the developing roller 31 moves upward in the gravity direction during image formation. It is arranged in the area to be. Further, it may be arranged in a region 81 (first quadrant) corresponding to a region above the horizontal straight line passing through the rotation center O of the developing roller 31 in the gravity direction. The reason why each part is arranged at this position is to make the toner charging on the developing roller 31 due to the toner circulation W and the toner reservoir S described above more effective. This will be described in detail with reference to FIG.

  FIG. 6 is an enlarged view of a region 81 in FIG. The contact portion 34N restricts the flow of the toner T that rises along the rotation direction R1 of the developing roller 31, and the restricted toner T flows downward due to its own weight. That is, the regulated toner T returns by its own weight toward the upstream side in the rotation direction R1 of the developing roller 31, and forms the preferable toner circulation W described above.

  Further, by stopping the toner conveying member 33 at a predetermined position, the toner reservoir S is created in the space formed by the developing roller 31 and the toner conveying means 33. Therefore, the toner accumulated in the toner reservoir S can be carried on the developing roller 31.

  Here, by arranging the center L of the shaft portion 33a of the toner conveying portion 33 in this region 81, the toner conveying member 33 can easily take a posture in which a good toner reservoir S is formed. Further, it is preferable that the center L of the shaft portion 33a of the toner conveying member 33 is disposed on the lower side in the gravity direction than the contact portion 34N. By doing so, the toner reservoir S can be formed in a smaller space.

  In this embodiment, the example in which the contact portion 34N of the developing blade 34 is used as the restricting portion for creating a preferable toner circulation W has been described, but other configurations may be used. For example, as shown in FIG. 7A, a toner regulating member 35 as a regulating unit may be disposed. Further, as shown in FIG. 7B, a part of the developing container 32 may be disposed in this portion and used as a restricting portion. In these cases, the proximity portion (35N, 32N) on the upstream side in the rotation direction R1 of the developing roller 31 functions as a regulating portion. In this case, the developing blade 34 is arranged on the downstream side in the rotation direction R1 of the developing roller 31 with respect to the toner regulating member 35 and a part of the developing container 32 having the function of the regulating unit.

<Operation of toner conveying member>
The operation of the toner conveying member will be described with reference to FIGS.

  The toner conveying member 33 stops in at least a part during image formation and rotates in at least part during non-image formation in conjunction with the contact / separation operation of the developing roller 31 and the photosensitive drum 10.

  Here, as described above, “at the time of image formation” means a position where the electrostatic latent image formed on the surface of the photosensitive drum 10 based on the image information is in contact with the photosensitive drum 10 and the developing roller 31 (developing position). Is reached and the developing device 3 is converting the electrostatic latent image into a toner image. “At the time of non-image formation” is when the developing device 3 does not visualize the electrostatic latent image.

  The reason why the toner conveying member 33 is stopped and operated at the above timing will be described below.

  First, the toner conveying member 33 is stopped at the time of image formation in order to stably carry the toner on the developing roller 31. As described above, in order to stably carry the toner, it is necessary to form the toner circulation W and the toner reservoir S (see FIG. 6). If the toner conveying member 33 is operated during image formation, as shown in FIG. 8A, when the front end KF of the toner conveying member 33 is located at a position away from the developing roller 31, the toner circulation W also becomes the toner. The reservoir S is not formed. Therefore, during the image formation, it is necessary to stop the conveying portion 33b of the toner conveying member 33 in the vicinity of the developing roller 31 and form the toner reservoir S.

  FIG. 8B shows the stopping posture of the toner conveying member 33. In this stop posture, the front end portion KF of the toner conveying member 33 is closer to the center of the developing roller 31 than the rear end portion KB that is the end portion on the shaft portion side. The toner T on the toner conveying member 33 forms a toner reservoir S and is in contact with the developing roller 31. On the other hand, the developing roller 31 is rotating, and the toner regulated by the contact portion 34N creates a toner circulation W.

  When the toner conveying member 33 is in the stopped posture, the toner T is carried on the developing roller 31 by the toner circulation W and the toner reservoir S described above. As a result, the amount of toner T carried on the developing roller 31 when the toner conveying member 33 is in the stopped posture (the amount carried) is the same as when the toner conveying member 33 is in a posture other than the stopped posture (particularly, The posture in which the toner reservoir S is not formed). In other words, the toner conveying member 33 in the stopped posture forms a toner reservoir S in the vicinity of the developing roller, thereby applying an appropriate toner pressure to the developing roller 31 and increasing the amount of toner T carried on the developing roller 31. be able to.

  Whether or not the toner carrying member 33 is in the stopped posture and whether or not the carrying amount of the toner T on the developing roller 31 is increased can be confirmed by measuring the carrying amount of the toner T carried on the developing roller 31. . The stopping posture of the toner conveying member 33 may be a posture that can obtain a carrying amount necessary for image formation, and it is not necessary to select a posture that maximizes the carrying amount.

  As another confirmation method, there is a method in which the toner conveying member 33 is rotated and then stopped, and the state is confirmed by directly observing the state. That is, it is only necessary that the toner reservoir S is in contact with the developing roller 31 with the toner conveying member 33 stopped.

  Furthermore, as a simpler confirmation method, there is a method of actually forming an image and confirming whether there is an image defect due to insufficient toner carrying on the developing roller 31.

  Note that these confirmations include confirmation with a toner amount near the expected life when the developing device 3 is used.

  The stop position of the toner conveying means 33 is preferably a position close to the developing roller 31 of the toner conveying means 33.

  As shown in FIG. 8B, it is assumed that a straight line BF is drawn from the rear end KB of the transport unit 33b to the front end KF when the toner transport member 33 is stopped. It is desirable that this straight line BF intersects the surface of the developing roller 31 facing the inside of the developing container 32 on the upstream side in the rotation direction R1 of the developing roller 31 with respect to the contact portion 34N.

  Further, as shown in FIG. 8B, the center portion L of the shaft portion 33 a of the toner conveying member 33 passes through the end portion on the upstream side in the rotation direction of the developing roller 31 in the contact portion 34 </ b> N of the developing blade 34. Draw a straight line LN. Further, a tangent line LM on the lower side in the gravitational direction among the tangent lines drawn on the surface of the developing roller 31 is drawn from the center L of the shaft portion 33 a of the toner conveying member 33. At this time, the front end portion KF of the transport unit 33b in the stop posture may be positioned between the straight line LN and the tangent line LM. In this way, a preferable toner circulation W and toner reservoir S can be formed. In the configuration shown in FIG. 7, the straight line LN described above may be a straight line that passes through the proximity portion (35N, 32N) on the upstream side in the rotation direction.

  Further, as shown in FIG. 8C, when the conveyance portion 33b of the toner conveyance member 33 is flexible, the conveyance portion 33b may be bent downward. At this time, the same effect can be expected if the tip K0 when it is assumed that the transport part 33b is not bent is positioned between the straight line LN and the tangent line LM.

  Here, the stop posture of the toner conveying member will be further described with reference to FIG.

  When the toner conveying member 33 is stopped, when the straight line drawn from the front end KF toward the rear end KB is directed downward in the gravity direction (when the front end KF is directed upward in the gravity direction), the inclination is increased. If it is larger, the toner T falls in a direction away from the developing roller 31. Therefore, at this time, the angle formed between the straight line drawn from the front end portion KF toward the rear end portion KB and the horizontal line is preferably small, and is preferably smaller than the repose angle of the toner T (FIG. 9 ( a)).

  Further, when the toner conveying member 33 is stopped, when a straight line drawn from the front end KF toward the rear end KB is directed upward in the gravity direction (when the front end KF is directed downward in the gravity direction), A larger inclination is preferred. Furthermore, the angle θ formed by the straight line drawn from the front end KF toward the rear end KB and the horizontal line is preferably larger than the repose angle of the toner T itself (FIG. 9B). By doing so, the toner T on the conveying portion 33b of the toner conveying member 33 is likely to be accumulated in the toner reservoir S formed on the developing roller 31 side, so that the toner T can be used efficiently. In addition, when the conveyance part 33b has flexibility, the angle | corner which the straight line drawn toward the rear-end part KB from the front-end | tip part K0 assumed that the conveyance part 33b was not bent, and a horizontal line (theta) However, if the above relationship is satisfied, the same effect can be expected (FIG. 9C).

  Further, it is desirable that the toner conveying member 33 and the developing roller 31 are separated from each other when the toner conveying member 33 is stopped. This is to prevent the developing roller 31 and the toner conveying member 33 from being worn out by rotating only the developing roller 31 while both are in contact with each other. In order to form a good toner reservoir S, it is desirable that the gap between the toner conveying member 33 and the developing roller 31 in the stopped position is approximately 2 mm or less.

  Next, the reason why the toner conveying member 33 is rotated during non-image formation will be described with reference to FIG. The reason is to refresh the state of the toner accumulated in the toner reservoir S.

  If the toner conveying member 33 is kept stopped, when the remaining amount of toner is large, as shown in FIG. 10A, the toner itself may be excessively pressured to generate agglomerated toner. The agglomerated toner is clogged to form a non-movable layer T1, and the conveyance of the toner T to the developing roller 31 side is stopped. Therefore, the toner T is loosened by rotating the toner conveying member 33, and the state of the toner near the developing roller 31 is refreshed. As a result, the toner pressure on the developing roller 31 is prevented from becoming excessive, and the developing roller 31 can carry the toner satisfactorily.

  Further, when the remaining amount of toner is small, as shown in FIG. 10B, it is conceivable that the toner in the toner reservoir S where the toner is consumed is partially depleted. Therefore, the toner conveying member 33 is rotated to replenish the toner, and the toner T2 far from the developing roller 31 and the toner T below the shaft portion 33a in the gravitational direction are actively conveyed to the vicinity of the developing roller 31. To do. By doing so, the toner T in the developing container 32 can be used efficiently.

<Stopping toner transport member>
In the present embodiment, the rotation and stop of the toner conveying member 33 are synchronized with the separation / contact between the photosensitive drum 10 and the developing device 3. At the time of contact (at the time of image formation), the rotation gear (not shown) of the toner conveying member 33 is detached from the drive input unit 36 and the toner conveying member 33 stops. On the other hand, at the time of separation (at the time of non-image formation), the rotation gear of the toner conveying member 33 and the drive input unit 36 are engaged with each other so that the toner conveying member 33 operates.

  Therefore, the control unit 99 (see FIG. 1) in the image forming body can control the stop posture of the toner conveying member 33 by controlling the contact / separation driving unit 65 and controlling the separation time during non-image formation. In at least a part of the image formation, the toner conveying member 33 can be in a stopped posture.

  Another method of rotating and stopping the toner conveying member 33 will be described with reference to FIG. As shown in FIG. 11A, the toner transport member 33 is provided with a transport drive member 33 c that drives the toner transport member 33. The conveyance driving member 33c is provided with a conveyance positioning portion 33d that comes into contact with a stopper member described later.

  The developing device 3 includes a transport input member 37 that receives a drive input from the drive input unit 36 and drives the transport drive member 33c. The conveyance input member 37 is disposed coaxially with the conveyance driving member 33c. And it connects with the conveyance drive member 33c via the friction member 38 as a difference absorption member arrange | positioned between the conveyance input member 37 and the conveyance drive member 33c.

  As shown in FIG. 11B, the developing device 3 is provided with a stopper member 39 that contacts the conveyance positioning portion 33d and stops the toner conveyance member 33, and a stopper regulating portion 40 that determines the position of the stopper member 39. It has been.

  As shown in FIG. 11 (b), the stopper member 39 may be in a locked state in which the stopper member 39 rotates around the shaft 39a and comes into contact with the first abutting portion 40a of the stopper regulating portion 40 to stop the conveyance positioning portion 33d. it can. Further, as shown in FIG. 11C, the stopper member 39 can be in a released state in which the stopper member 39 abuts against the second abutting surface 40b of the stopper regulating portion 40 and is separated from the conveyance positioning portion 33d.

  At the time of image formation, the stopper member 39 is locked by the spring 41 as shown in FIG. At this time, the conveyance positioning portion 33d is disposed at a position where the toner conveyance member 33 is brought into a stop posture when it comes into contact with the stopper member 39.

  On the other hand, as shown in FIG. 11C, when the photosensitive drum 10 and the developing roller 31 are separated from each other, the stopper member 39 is pressed in the F direction by the contact / separation driving unit 65 (see FIG. 1) to release the photosensitive drum 10 and the developing roller 31. Take. At this time, the stopper member 39 is separated from the conveyance positioning portion 33d, and the conveyance driving member 33c can freely rotate. Thus, the stopper member 39 can be switched between the locked state and the released state.

  At the time of image formation, the conveyance input member 37 receives driving from the drive input unit 36 and tries to rotate the conveyance driving member 33c in the R2 direction via the friction member 38. However, since the conveyance positioning portion 33d is in contact with the stopper member 39, the friction member 38 slips and the conveyance drive member 33c does not move.

  On the other hand, when the photosensitive drum 10 and the developing roller 31 are separated from each other, the transport driving member 33c can freely rotate as described above. Therefore, the conveyance input member 37 can rotate the conveyance driving member 33 c via the friction member 38.

  When the photosensitive drum 10 and the developing roller 31 abut again, the pressing of the contact / separation driving unit 65 is released, the stopper member 39 is locked again, and the conveyance positioning unit 33d is stopped at a desired phase.

  The differential absorbing member may be a means other than the friction member 38. Further, the transport driving member 33c, the transport positioning portion 33d, and the friction member 38 can be provided at locations other than those shown in the present embodiment as long as the toner transport member 33 can be brought into a stop posture.

  In the present embodiment, a configuration is shown in which the conveyance driving member 33c is stopped during image formation in conjunction with the separation and contact operations of the photosensitive drum 10 and the developing roller 31. However, the present invention is not limited to this. That is, it is only necessary that the toner conveying member 33 can be in a stopped posture during image formation. For example, the toner conveying member 33 may be in a stopped posture by controlling another driving means (stepping motor or the like). Further, the stopper member 39 may be moved by another driving means and a control unit.

  In the present exemplary embodiment, the toner conveying member 33 has a configuration in which the conveying portion 33b rotates around the shaft portion 33a. However, other configurations may be used. That is, it is only necessary that the toner T is stirred and stopped when the image is formed, and the toner reservoir S can be formed in the vicinity of the developing roller 31. Therefore, a configuration in which the conveyance unit 33b swings or a link mechanism or the like is connected to the shaft unit 33a and reciprocates with respect to the developing roller 31 may be employed.

  As described above, in the configuration of the present invention, the toner conveying member 33 is operated at the time of non-image formation and stopped at the time of image formation, so that the toner conveying member 33 has two roles of toner agitation and toner supply. . As a result, the toner conveying member 33 can be operated during non-image formation to eliminate aggregation of the toner T, and the toner conveying member 33 can be stopped during toner image formation to form the toner reservoir S. Further, a preferable toner circulation W can be obtained by the contact portion 34N. As a result, the toner can be supplied by efficiently utilizing the weight of the toner, so that it is possible to stably supply the toner to the developing roller 31 while achieving a reduction in size and simplification of the developing device 3. Become.

[Example 2]
A second embodiment of the present invention will be described with reference to FIG.

  In the present embodiment, the different components from the first embodiment will be described, and the description of the same components as those in the first embodiment will be omitted.

  A feature of the present embodiment is that, instead of the developing roller 31 described in the first embodiment, a dielectric portion capable of holding charges and a conductor portion adjacent to the dielectric portion are exposed on a surface with a small area. That is, the developing rollers 131 configured to be mixed are used.

  As shown in FIG. 12A, the developing roller 131 includes an elastic layer 131b made of a conductive rubber material on the outer periphery of the shaft core 131a. Further, on the surface of the developing roller 131, a conductor part (first volume resistance part) 131e having a volume resistance of 10 ^ 11 Ω · cm or less and a dielectric part (second volume of 10 ^ 13 Ω · cm or more) are provided. A resistance layer 131d is provided with a surface layer 131c. That is, the developing roller 131 is configured such that the surface carrying the toner T has a plurality of dielectric portions scattered on the surface made of the conductor portion. The developing roller 131 can be manufactured by forming a surface layer made of a conductive resin material in which dielectric particles are dispersed on the elastic layer 131b by, for example, coating and polishing the surface.

  FIG. 12B is a plan view of the developing roller 131, and FIG. By charging the dielectric portion 131d, a minute closed electric field (microfield) as shown by the electric lines of force E in FIG. 12C is formed. The outer diameter of the dielectric part 131d is desirably about 5 to 500 μm. This is an optimum value for holding charges on the surface and suppressing image unevenness. When the outer diameter is greater than 5 μm, a sufficient charge can be retained on the surface of the dielectric portion 131d and a sufficiently small closed electric field can be formed.

  The above-described charging of the dielectric portion 131d increases as the chance of rubbing between the toner T and the developing roller 131 increases. That is, the more the toner T moves on the surface of the developing roller 131, the greater the charge amount of the dielectric portion 131d. In order to increase the movement of the toner T on the surface of the developing roller 131, the toner circulation W described in the first embodiment may be activated. In order to activate the toner circulation W, a restricting portion (such as the abutting portion 34N in the first embodiment) may be provided, and the toner conveying member 33 may be operated in the same manner as in the first embodiment. As a result, the charge amount of the dielectric portion increases, and a minute closed electric field is formed in the adjacent portion between the dielectric portion and the conductor portion. The toner conveyed to the toner reservoir S near the developing roller 131 by the toner conveying member 33 receives a gradient force and is sucked and carried on the surface of the developing roller 131.

  As described above, in this embodiment, the toner circulation W in the vicinity of the developing roller 131 can charge not only the toner on the surface of the developing roller 131 but also the dielectric portion formed on the surface of the developing roller 131. . Therefore, a larger number of minute closed electric fields can be formed, the gradient force for attracting the toner is increased, and a larger amount of toner can be carried.

[Example 3]
A third embodiment of the present invention will be described with reference to FIGS.

  A feature of the present embodiment is that when image formation is continuously performed on a plurality of recording materials P, toner conveyance is performed during image formation of images transferred to the preceding recording material P and the succeeding recording material P, respectively. It is to move the member 33. This loosens the toner near the developing roller 31 and stabilizes the toner supply to the developing roller.

  The configuration other than the toner conveying member is the same as that described in the first or second embodiment. In the present embodiment, a configuration different from the configuration described in the first embodiment will be described.

  FIG. 13 is a cross-sectional view of the image forming apparatus used in this embodiment.

  The image forming apparatus according to the present exemplary embodiment is provided with a swing driving unit 90 that drives a swing member, which will be described later, based on image information sent from an information processing device (not shown). The swing drive unit 90 is controlled by the control unit 99.

  Next, the operation of the toner conveying member 33 in this embodiment will be described with reference to FIG.

  As described above, at the time of image formation, it is necessary to stop the toner conveying member 33 in order to form the toner reservoir S in the vicinity of the developing roller 31. However, if the toner conveying member 33 is kept stopped, when the remaining amount of toner is large, as shown in FIG. 14A, the pressure is excessive due to the weight of the toner itself, and aggregated toner is generated. The agglomerated toner is clogged to form a non-moving layer T1, and the toner supply to the developing roller 31 side is stopped. Further, when the remaining amount of toner is small, as shown in FIG. 14B, the toner in the toner reservoir S where the toner consumption is large is partially depleted and an appropriate carrying amount cannot be obtained. Therefore, even in the case of so-called continuous printing in which image formation is continuously performed on a plurality of recording media, the toner T is loosened by moving the toner conveying member 33 at a constant timing, and a toner pool without density is formed. It is desirable to reform.

  Even in the case of continuous printing, the time from the end of the image formation of the image transferred to the preceding recording material P to the start of the image formation of the image transferred to the succeeding recording material P (hereinafter simply referred to as “inter-recording material interval”). ")", No image is formed. Therefore, the toner conveying member 33 can be operated between the recording materials to loosen the toner T. When the image is formed, the toner conveying member 33 is stopped again, so that the toner reservoir S can be re-formed near the developing roller 31. That is, the toner supply to the developing roller 31 can be stabilized without hindering the image forming operation.

  The operation of the toner conveying member 33 between the recording materials is a so-called swinging operation that moves the toner conveying member 33 back and forth in the rotational direction, as shown in FIGS. 14 (c) and 14 (d). May be. With this method, the operation time can be shortened compared to the method of rotating the toner conveying member 33. For this reason, it becomes easy to operate between recording materials when performing continuous printing. Therefore, it is possible to secure a good carrying amount by loosening the toner T without hindering the image forming operation and re-forming a toner pool having no density in the vicinity of the developing roller 31. That is, the toner supply to the developing roller can be stabilized.

  The swinging operation of the toner conveying member 33 between the recording materials will be described with reference to FIG. FIG. 15 is a diagram illustrating the toner transport member 33 and a swinging member 92 that swings the toner transport member 33. The toner conveying member 33 is in the stop posture described in the first embodiment. In this embodiment, the axial direction of the shaft portion 33a of the toner conveying member 33 is simply referred to as “longitudinal direction”.

  In the vicinity of the toner conveying member 33, a swing member 92 for operating the toner conveying member 33 is provided between the recording materials. The swinging member 92 has a swinging shaft 92a, a swinging plate 92b that rotates and comes into contact with the transport part 33b, and a swinging input part 92c. The swing shaft 92a is made of HIPS or the like, and can rotate in the direction of arrow R4 upon receiving an operation input from the swing drive section 90 shown in FIG. 12 to the swing input section 92c.

  The swing input portion 92c is provided with a spring-like pressing member (not shown) that can expand and contract in the longitudinal direction. By the expansion and contraction of the pressing member, the swing member 92 can move in the longitudinal direction.

  The swinging part 92b is made of a thin elastic body such as a polyethylene terephthalate sheet having a thickness of about 50 to 200 μm. Both the length in the rotation radius direction and the length in the rotation axis direction of the swinging portion 92 b are configured to be shorter than the conveyance portion 33 b of the toner conveyance member 33. The swinging portion 92b is configured to come into contact with the transporting portion 33b of the toner transporting member 33 in a stopped posture when the swinging member 92 rotates.

  FIG. 15A shows the operation of the swinging member 92 between the recording materials.

  The swing member 92 receives an operation input from the swing drive unit 90 shown in FIG. 13 and moves in the longitudinal direction. When the swinging member 92 rotates, the swinging part 92b enters to a position where the swinging part 92b comes into contact with the transporting part 33b. Next, when the swing member 92 is rotated, the swing portion 92b comes into contact with the transport portion 33b. At this time, the transport unit 33b is not rotated because it is stopped. Then, it is deformed by the elasticity of the swinging plate 92b and the conveying portion 33b, and moves forward and backward in the rotational direction of the toner conveying member 33.

  Next, FIG. 15B shows the operation of the swinging member 92 at a time other than the interval between sheets.

  The swing member 92 receives an operation input from the swing drive unit 90 shown in FIG. 12 and moves in the longitudinal direction. Even when the toner conveying member 33 rotates, the conveying portion 33b is retracted to a position where it does not contact the swinging portion 92b. By doing so, it is possible to prevent the operation of the toner conveying member 33 during non-image formation described in the first embodiment from being hindered.

  In this embodiment, the configuration in which the toner conveying member 33 is swung using the swinging member 92 has been described in detail, but the present invention is not limited to this. The movement of the toner conveying member 33 during non-image formation as described in the first embodiment may be performed between the recording materials.

  As described above, by moving the toner conveying member 33 between the recording materials, when image formation is continuously performed on a plurality of recording materials, the toner is loosened without hindering the image forming operation, and the developing roller 31 is released. The toner supply to the toner can be stabilized.

[Example 4]
A fourth embodiment of the present invention will be described with reference to FIGS.

  The feature of the present embodiment is that the operation of the toner conveying member is performed by a stepping motor or the like that operates in synchronization with the pulse power and can also rotate in the reverse direction.

  The configuration other than the toner conveying member is the same as that described in the first or second embodiment.

  FIG. 16 is a diagram showing an image forming apparatus used in this embodiment. FIG. 17 is a diagram illustrating the toner conveying member 133 used in this embodiment.

  The image forming apparatus includes a stepping motor 95 that rotates and stops the toner conveying member 133. The stepping motor 95 is controlled by the control unit 99.

  A conveyance driving member 133 c that receives driving from the stepping motor 95 is provided on the shaft portion 133 a of the toner conveyance member 133. The transport driving member 133c and the stepping motor 95 are configured to be coupled at a specific phase. Further, in the rotation direction of the toner conveying member 133, the phase of the conveying driving member 133c and the conveying portion 133b is also a specific phase.

  That is, the image forming apparatus according to the present exemplary embodiment can independently control the operation and stop of the toner transport member 133 by the stepping motor 95 and directly control the stop posture of the toner transport member 133.

  At the time of image formation, the toner conveying member 133 is controlled to the stop posture so as to form the toner reservoir S as described in the first embodiment. Further, at the time of non-image formation, the toner conveying member 133 can be moved to loosen the toner T.

  Further, the toner conveying member 133 can be rotated also between the recording materials when forming an image on a plurality of recording materials. In addition, a motion that alternately repeats forward rotation and reverse rotation can be transmitted to the transport driving member 133c, and the toner transport member 133 can be moved back and forth in the rotational direction.

  As described above, the operation and stop of the toner conveying member 133 can be controlled by moving the toner conveying member 133 with the stepping motor 95. Therefore, the toner can be stably supplied to the developing roller 31. Further, the toner conveying member 133 can be moved between the recording materials to loosen the toner T. Therefore, even when image formation is continuously performed on a plurality of recording materials, the toner supply to the developing roller 31 can be stabilized without hindering the image formation operation.

[Example 5]
A fifth embodiment of the present invention will be described with reference to FIG.

  The feature of this embodiment is that the photosensitive drum 10, the charging roller 11, the cleaning device 5, and the developing device 3 are integrally incorporated to constitute a process cartridge PC that is detachable from the main body of the image forming apparatus.

  By using such a cartridge system, the same effects as those of the first embodiment described above can be obtained, and an image forming apparatus excellent in usability can be provided by reducing the maintenance load.

  The process cartridge PC may have a structure that can be divided into a block BR-A and a block BR-B surrounded by a broken line.

3 Developing Device 31 Developer Carrier (Developing Roller)
32 Developing container 33, 133 Conveying member (toner conveying member)
33a, 133a Shaft part 33b, 133b Conveying part 33c, 133c Conveying drive member 33d Conveying positioning part 34N Restricting part (contact part)
35N Toner regulating member 39 Stopper member 65 Contact / separation driving unit 92 Oscillating member 92a Oscillating shaft 92b Oscillating plate 92c Oscillating driving unit 95 Stepping motor 99 Control unit 131d Second volume resistance unit 131e First volume resistance unit T Developer (toner)
KF Front end of the transport section KB End of the transport section on the shaft side (rear end)
BF Straight line drawn from the rear end to the front end L Center of the shaft O Center of rotation of the developing roller

Claims (17)

Developer,
A developer container containing the developer;
A developer carrying member rotatably supported by the developing container and carrying the developer;
A transport member that is provided inside the developer container and includes a shaft portion and a transport portion connected to the shaft portion, and transports the developer;
A developing device used in an image forming apparatus including:
A regulation part for regulating the developer carried on the developer carrying body;
The regulating portion is a region around the developer carrier,
In the region where the surface of the developer carrier moves upward in the direction of gravity during image formation,
Arranged to face the developer carrier,
The conveying member stops at least at a part during image formation and takes a stop posture;
When the transport member is in the stop position,
The amount of the developer carried on the developer carrier is:
The developing device characterized in that the carrying member is larger than the carrying amount when the posture is different from the stop posture. In the stop posture,
A straight line drawn from the rear end portion, which is the end portion on the shaft portion side, of the transport portion to the front end portion,
On the upstream side in the rotation direction of the developer carrier relative to the restriction portion,
The developing device according to claim 1, wherein the developing device intersects a surface of the developer carrying member facing the inside of the developing container. In the stop posture,
In the case where the straight line drawn from the front end to the rear end is directed downward in the direction of gravity,
The angle formed by the straight line drawn from the front end portion to the rear end portion and the horizontal line is
The developing device according to claim 2, wherein the developing device is smaller than an angle of repose of the developer. In the stop posture,
In the case where the straight line drawn from the front end to the rear end is directed upward in the direction of gravity,
The angle formed by the straight line drawn from the front end portion to the rear end portion and the horizontal line is
The developing device according to claim 2, wherein the developing device is larger than an angle of repose of the developer. In the stop posture,
Of the tangent lines drawn from the center of the shaft portion to the surface of the developer carrying member, the tangent line on the lower side in the gravity direction and the end of the regulating portion on the upstream side in the rotation direction of the developer carrying member from the center of the shaft portion Between the straight line drawn by
The developing device according to claim 2, wherein the tip portion is located. The center of the shaft portion and the restricting portion at the time of image formation are
Of the area around the developer carrier,
A region where the surface of the developer carrying member moves upward in the direction of gravity during image formation;
6. The developing device according to claim 1, wherein the developing device is disposed in a region above a horizontal line passing through a rotation center of the developer carrying member in a gravitational direction. The center of the shaft during image formation is
The developing device according to claim 1, wherein the developing device is disposed below the regulating portion in a direction of gravity. The conveying member is
8. The developing device according to claim 1, wherein the developing device is rotated in a direction in which the developer located on the lower side in the gravity direction from the shaft portion is conveyed toward the developer carrying member. 9. In the stop posture,
The developing device according to claim 1, wherein the conveying member is separated from the developer carrying member. 10. The developer carrying member according to claim 1, wherein a surface carrying the developer is configured such that a plurality of dielectric parts are scattered on a surface made of a conductor part. The developing device according to claim 1. The developer carrier is
It is configured to be able to contact and separate from an image carrier that carries an electrostatic latent image,
The developing device according to claim 1, wherein the conveying member stops at least at a part while the image carrier and the developer carrier are in contact with each other. .   The developing device according to claim 1, further comprising a stopper member that brings the conveying member into the stop posture. A transport driving member for driving the transport member;
A conveyance positioning portion provided on the conveyance member and in contact with the stopper member;
Have
The developing device according to claim 12, wherein the transport positioning unit brings the transport member into the stop posture when abutting on the stopper member. A developing device according to any one of claims 1 to 13,
A control unit that controls the transport member to be in the stop posture;
An image forming apparatus comprising: In the case where image formation is continuously performed on a plurality of recording media,
From the end of image formation of the image to be transferred to the preceding recording medium,
Until the start of image formation of the image to be transferred to the subsequent recording medium,
The image forming apparatus according to claim 14, wherein the conveying member is moved. In the case where image formation is continuously performed on a plurality of recording media,
From the end of image formation of the image to be transferred to the preceding recording medium,
Until the start of image formation of the image to be transferred to the subsequent recording medium,
The image forming apparatus according to claim 15, wherein the conveying member is moved back and forth in the rotation direction of the conveying member. A rocking member having a rocking plate that rotates and comes into contact with the transport unit;
From the end of image formation of the image to be transferred to the preceding recording medium,
Until the start of image formation of the image to be transferred to the subsequent recording medium,
The image forming apparatus according to claim 16, wherein the rocking member is rotated to bring the rocking plate into contact with the transport unit.

Images