JP2008185950A - Developing device, and image forming apparatus mounted therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device where toner is not partially retained in a developing vessel, the toner is sufficiently uniformly dispersed in the longitudinal direction inside the vessel, and the formation of an image with high quality can be performed. <P>SOLUTION: In the developing device 30, a developing vessel 34 includes a stirring/carrying member 50 for performing the stirring and carrying of toner. The stirring/carrying member 50 includes: an axis part 51 so as to be the center of rotation; and a sheet-shaped stirring blade 52 fixed to the axis part 51 in a form of elongating from the axis part 51 to the outside in the radial direction, and further, at least either region of both the edge parts in the axial direction includes a deflection part X carrying the toner from the edge part side toward the inside in the axial direction, and the other region includes a stirring part Y uniformly dispersing the toner in the axial direction. Thus, in the vicinity of the edge part in the longitudinal direction on the side of the deflector part X within the developing device 34, the amount of the toner can be made relatively small, and, in the stirring part Y as the region such as the central part in the longitudinal direction other than that, the toner can be uniformly stirred and moved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a developing device applicable to an electrophotographic image forming apparatus represented by a copying machine or a printer. The present invention also relates to an image forming apparatus equipped with the developing device.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, a photosensitive drum is widely used as an image carrier. A general image forming operation using the photosensitive drum is as follows. The surface of the photosensitive drum is uniformly charged with a predetermined potential by a charging device, and by irradiating the LED light or the like of the exposure device there, the potential is partially attenuated to form an electrostatic latent image of an original image. Is done. The electrostatic latent image is developed with a developing device to form a toner image. After the transfer of the toner image onto the paper, the remaining toner is cleaned on the surface of the photosensitive drum by the cleaning device, and the charge removal is performed by irradiating the neutralization light by the neutralization device in preparation for the next image forming operation. Is called.

  In the developing device which is the main part of the image forming operation as described above, a predetermined amount of toner is always stored in the developing container, and additional toner is replenished when the remaining amount is used for development and the remaining amount is low. . At this time, generally, toner is introduced into the developing container from the toner supply container disposed above the developing device by the action of gravity or a conveying member.

  Here, since the developing container accommodates the developing roller, the developing container usually has an elongated shape corresponding to the shape of the developing roller. In order to perform the formation of a high quality image, the toner accommodated in the developing container needs to be uniformly dispersed along the longitudinal direction of the developing roller in the developing container. For this reason, in the developing device, a method is widely adopted in which a stirring (conveying) member that rotates about the axis is provided and the toner is uniformly dispersed in the longitudinal direction in the developing container by the rotating operation.

Examples of such a developing device can be found in Patent Documents 1 and 2. Both of the developing devices described in Patent Documents 1 and 2 include a stirring (conveying) member provided with a sheet member (stirring blade) having an opening, thereby conveying the toner toward the developing roller while stirring the toner. I am doing so.
JP 2001-100500 A (page 5, FIG. 2) Japanese Patent Laid-Open No. 11-311895 (page 3, FIG. 2)

  In the developing device described in Patent Document 1, the toner is stably supplied to the developing roller without receiving a large resistance with the rotation of the agitating and conveying member by the two sheet members having a plurality of openings arranged in a staggered manner. I can do it. The staggered openings are considered to move the toner in the longitudinal direction in the developing container. However, in such a stirring and conveying member, a configuration sufficient to move the toner is applied to the sheet member and the opening. It has not been. Therefore, it is difficult to disperse the toner sufficiently uniformly over the entire length in the developing container.

  As a result, a large amount of toner concentrates in the vicinity of a replenishment location such as a toner replenishment port of the developing container, and there is a possibility that toner that will not be used for a long time stays in a location facing this. As a result, when the staying toner deteriorates and is supplied to the developing roller, an image defect may occur. Further, when a large amount of toner concentrates on the toner remaining amount detecting means, the remaining amount detecting means may identify that the amount of toner is larger than the amount of toner actually stored in the developing container. As a result, the amount of toner stored in the developing container is actually smaller than a predetermined amount that can be suitably developed, and therefore, the supply of toner becomes insufficient and image defects may occur.

  In the developing device described in Patent Document 2, toner is collected at the central portion in the axial direction of the developing roller along with the rotation of the agitating / conveying member by a sheet member having a plurality of parallelogram-shaped openings. . However, in such a stirring / conveying member, a large amount of toner concentrates in the central portion in the axial direction of the developing roller, and there is a possibility that toner that will not be used for a long time stays at both ends. As a result, when the staying toner deteriorates and is supplied to the developing roller, an image defect may occur at both ends of the developing roller.

  The present invention has been made in view of the above points. In a developing device including an agitating and conveying member that rotates about an axis and conveys toner in a developing container toward a developing roller while agitating, the developing container includes: Even when a toner replenishing port, a remaining amount detecting means, etc. are locally disposed, the toner can be sufficiently dispersed in the longitudinal direction in the developing container without the toner staying in these places. An object of the present invention is to provide a developing device capable of forming a quality image. It is another object of the present invention to provide a high-performance image forming apparatus equipped with such a developing device.

  In order to solve the above-described problems, the present invention provides a developing container that contains toner, a developing roller that supplies toner to an image carrier on which an electrostatic latent image is formed, In the developing device including the agitating and conveying member that conveys the toner toward the developing roller while agitating, the agitating and conveying member includes a shaft portion serving as a rotation center and a shaft extending radially outward from the shaft portion. A sheet-like stirring blade fixed to the unit, and at least one region of both axial end portions, a deflection unit that conveys the toner from the end side toward the inner side in the axial direction, and other regions In addition, a stirring unit that uniformly disperses the toner in the axial direction is provided.

  In the developing device configured as described above, the stirring blade has a plurality of openings inclined from the fixed end side toward the free end side in a region corresponding to the deflection unit.

  In the developing device having the above-described configuration, a plurality of the stirring blades are provided in combination.

  Further, in the developing device having the above configuration, each of the plurality of stirring blades includes a stirring blade having a function of the deflecting unit and a function of the stirring unit, and a stirring blade having only a function of the stirring unit, These two kinds of stirring blades are provided with at least one stirring conveying member.

  In the developing device having the above-described configuration, each of the plurality of stirring blades includes a stirring blade that uniformly disperses the toner in the entire axial direction, and a stirring blade that has only the function of the deflecting unit. These stirring blades are provided with at least one stirring and conveying member.

  Further, in the developing device having the above configuration, each of the plurality of stirring blades has a plurality of openings inclined from the fixed end side toward the free end side in a region corresponding to the stirring unit. It was supposed that it was comprised by the pattern from which the inclination direction of an opening differs.

  Further, in the developing device configured as described above, each of the plurality of stirring blades is directed from the fixed end side toward the center side with respect to both ends in the axial direction, or in the center portion in the axial direction, in a region corresponding to the stirring portion. In contrast, each of the two stirring blades is provided with at least one of the two kinds of stirring blades.

  Further, in the developing device having the above-described configuration, each of the plurality of stirring blades has an opening corresponding to the stirring portion, and all the openings are open from the fixed end side to one end side in the axial direction, or the other side. It is configured by an opening inclined toward one of the end portions, and the stirring / conveying member includes at least one of these two types of stirring blades.

  In the developing device having the above-described configuration, the stirring and conveying member includes the plurality of stirring blades stacked.

  In the present invention, the developing device is mounted on the image forming apparatus.

  According to the configuration of the present invention, in the developing device including the agitating and conveying member that rotates about the axis and conveys the toner in the developing container toward the developing roller while agitating, the agitating and conveying member serves as the rotation center. The shaft portion and a sheet-like stirring blade fixed to the shaft portion so as to extend radially outward from the shaft portion, and at least one region of both end portions in the axial direction are axially inner from the end side. And a stirrer that disperses the toner uniformly in the axial direction in the other region, so that the end of the developing container in the longitudinal direction is caused by the action of the stirrer blades. In the vicinity, the toner amount can be relatively reduced, and in other regions such as the central portion in the longitudinal direction, the toner can be uniformly stirred and moved. As a result, even when a toner replenishing port and a remaining amount detecting means are arranged locally in the developing container, the toner is sufficiently dispersed in the longitudinal direction in the developing container without the toner staying in these places. Can be made. Therefore, it is possible to obtain a developing device capable of preventing the occurrence of image defects due to staying and deteriorated toner or toner shortage and performing high-quality image formation.

  Further, since the stirring blade has a plurality of openings inclined in the region corresponding to the deflecting portion from the fixed end side toward the free end side, by rotating the stirring blade, the inclination direction of the opening It is possible to move the toner along the line. This makes it possible to easily reduce the amount of toner in the vicinity of the end in the longitudinal direction in the developing container, and to uniformly agitate and move the toner in other areas such as the central portion in the longitudinal direction. Can do.

  Further, since a plurality of the stirring blades are provided in combination, it is possible to increase the amount of toner that can be moved per unit time as the stirring and conveying member rotates. As a result, the agitating / conveying performance of the toner is improved, and a desired toner distribution in the developing container can be obtained efficiently.

  Further, each of the plurality of stirring blades is composed of a stirring blade having the function of the deflection unit and the function of the stirring unit, and a stirring blade having only the function of the stirring unit. In addition, since at least one stirring and conveying member is provided, the deflection unit and the stirring unit can be configured with respect to the entire axial direction of the stirring and conveying member with a simple configuration using two stirring blades. it can. Accordingly, the toner can be sufficiently dispersed in the longitudinal direction in the developing container without the toner staying in a portion such as the toner supply port and the remaining amount detecting means.

  Each of the plurality of stirring blades is composed of a stirring blade that uniformly disperses the toner in the entire axial direction and a stirring blade that has only the function of the deflection unit, and these two types of stirring blades are stirred and conveyed. Since at least one member is provided, similarly to the above configuration, the deflecting unit and the stirring unit are configured with respect to the entire region in the axial direction of the stirring and conveying member by a simple configuration using two stirring blades. can do. Accordingly, the toner can be sufficiently dispersed in the longitudinal direction in the developing container without the toner staying in a portion such as the toner supply port and the remaining amount detecting means.

  Further, each of the plurality of stirring blades has a plurality of openings inclined in a region corresponding to the stirring portion from the fixed end side toward the free end side, and the inclination direction of the opening is different for each stirring blade. Therefore, by rotating each stirring blade, it is possible to move the toner along the inclination direction of the opening. Thereby, the toner can be easily moved in various longitudinal directions in the developing container. Therefore, the toner can be dispersed sufficiently efficiently in the longitudinal direction in the developing container.

  Further, each of the plurality of stirring blades is directed from the fixed end side toward the central portion side with respect to both ends in the axial direction in the region corresponding to the stirring portion, or toward both ends with respect to the central portion in the axial direction. It is composed of an opening that is inclined to any direction, and these two kinds of stirring blades are provided with at least one stirring / conveying member, so that one stirring blade moves to the center in the longitudinal direction in the developing container. The toner can be moved, and the toner can be moved to both end sides by another stirring blade. Thus, the toner can be moved back and forth from both ends in the developing container to the center and from the center to both ends, and the toner can be efficiently stirred. Therefore, the action of dispersing the toner in the longitudinal direction in the developing container can be improved.

  Further, each of the plurality of stirring blades has an opening in a region corresponding to the stirring unit, from the fixed end side to one end side in the axial direction or the other end side. These two types of stirring blades are provided with at least one stirring / conveying member. Therefore, the toner is transferred to one end side in the longitudinal direction in the developing container with one stirring blade. And the toner can be moved to the other end side with another stirring blade. Accordingly, the toner can be moved back and forth from the end in the longitudinal direction in the developing container, and the toner can be efficiently stirred. Therefore, the action of dispersing the toner in the longitudinal direction in the developing container can be improved.

  Further, since the stirring and conveying member is provided with a plurality of stirring blades stacked, the plurality of stirring blades continuously rotate at short time intervals to stir the toner. As a result, the stirring force increases as compared with the case where the stirring blades are not stacked, and the toner can be easily moved along the longitudinal direction in the developing container. Accordingly, it is possible to further enhance the action of dispersing the toner in the longitudinal direction in the developing container.

  In the present invention, since the developing device is mounted on the image forming apparatus, even when a toner replenishing port, a remaining amount detecting means, and the like are disposed locally in the developing container of the developing device, The toner can be sufficiently dispersed in the longitudinal direction in the developing container without the toner staying in the place, and a high-performance image forming apparatus capable of forming a high-quality image can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an outline of the structure of an image forming apparatus equipped with the developing device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a color printer which is an example of an image forming apparatus. This color printer is a type using an intermediate transfer belt. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper feed cassette 3 is disposed below the inside of the main body 2 of the printer 1. The paper P is stacked and accommodated inside the paper feed cassette 3. Then, the paper P is sent out toward the upper right of the paper feed cassette 3 in FIG. The paper feed cassette 3 can be pulled out horizontally from the front side of the main body 2, that is, from the right side in FIG.

  A paper feed path 4, a paper feed transport roller 5, a registration roller 6, and an image forming unit 20 are disposed downstream of the paper feed cassette 3 in the paper transport direction. The image forming unit 20 includes a photosensitive drum 21 which is a rotating image carrier at the center thereof. The photosensitive drum 21 rotates counterclockwise in FIG. Around the photosensitive drum 21, a charging device 22, a developing device 30, and a drum cleaning device 70 are sequentially arranged along the rotation direction.

  The developing device 30 is mainly composed of a rotary rack 31 that rotates clockwise in FIG. 1, and a total of four developing devices 32 are arranged at equal intervals in the circumferential direction on the rotary rack 31. The four developing devices 32 are a black developing device 32B, a yellow developing device 32Y, a magenta developing device 32M, and a cyan developing device 32C. The rotary rack 31 is rotated by driving means (not shown), and the four developing devices 32 are sequentially moved to a position facing the photosensitive drum 21 to supply toner as developer for each color to the surface of the photosensitive drum 21. Thus, a toner image is formed. Above the image forming unit 20, a toner supply container 7 for supplying toner to the developing device 30 and a supply pipe 8 are provided. The toner replenishing container 7 and the replenishing pipe 8 are arranged for each color side by side in the axial direction of the rotary rack 31.

  An optical unit 9 is provided above the image forming unit 20, and a laser beam L is emitted from the optical unit 9 toward the photosensitive drum 21. The broken line in the figure indicates the laser beam L.

  An intermediate transfer belt 10 using an intermediate transfer member in the form of an endless belt is disposed immediately below the photosensitive drum 21. The intermediate transfer belt 10 is supported by being wound around a plurality of rollers, and rotates clockwise in FIG. The intermediate transfer belt 10 is pressed against the photosensitive drum 21 from below to form a primary transfer portion 80.

  A secondary transfer unit 11 is disposed at a position where the intermediate transfer belt 10 is suspended on the sheet conveyance path. The paper P is inserted into the secondary transfer nip portion formed in the secondary transfer portion 11 to be brought into pressure contact with the intermediate transfer belt 10 and the toner image is transferred. A belt cleaning unit 12 is provided downstream of the secondary transfer unit 11 in the sheet conveyance direction.

  A fixing unit 13, a discharge paper transport path 14, and a paper discharge unit 15 are disposed downstream of the image forming unit 20 and the secondary transfer unit 11 in the paper transport direction. The paper discharge unit 15 is provided on the upper surface of the main body 2 at a position where the printed paper P can be taken out from the outside.

  A double-sided printing paper conveyance path 16 is disposed below the fixing unit 13 and the secondary transfer unit 11 and between the paper feeding cassette 3. The double-sided printing paper conveyance path 16 branches from the middle of the discharge paper conveyance path 14, passes under the fixing unit 13 and under the secondary transfer unit 11, and conveys the paper for paper feeding immediately upstream of the registration roller 6. It merges with Road 4.

  Next, a detailed configuration around the image forming unit 20 of the printer 1 will be described with reference to FIG. FIG. 2 is a partially enlarged vertical cross-sectional view showing the periphery of the image forming unit.

  As shown in FIG. 2, the image forming unit 20 includes a photosensitive drum 21 as an image carrier at the center thereof. As described above, the charging device 22, the developing device 30, and the drum cleaning device 70 are disposed in the vicinity of the photosensitive drum 21 along the rotation direction. The primary transfer portion 80 where the photosensitive drum 21 and the intermediate transfer belt 10 are in pressure contact is provided between the developing device 30 and the drum cleaning device 70 along the rotation direction of the photosensitive drum 21.

  The photosensitive drum 21 extends in the paper width direction perpendicular to the paper transport direction in the printer 1, that is, the depth direction of the paper surface of FIG. 2, and is arranged with its axis direction horizontal. The photosensitive drum 21 is an inorganic photosensitive drum in which an amorphous silicon photosensitive layer, which is an inorganic photoconductive material, is provided on the outside of a conductive roller-shaped substrate made of aluminum or the like by vacuum deposition or the like, and has a diameter of 30 mm. It is. The photosensitive drum 21 is rotated by a driving device (not shown) so that the peripheral speed thereof is substantially the same as the paper conveyance speed (for example, 100 mm / sec).

  The charging device 22 includes a charging roller 22 a in contact with the photosensitive drum 21 inside. The charging roller 22 a is pressed against the photosensitive drum 21 with a predetermined pressure, and rotates according to the rotation of the photosensitive drum 21. The surface of the photosensitive drum 21 is uniformly charged with a predetermined polarity and potential by the charging roller 22a.

  As described above, the developing device 30 is mainly composed of the rotary rack 31, and a total of four developing devices 32 are arranged at equal intervals in the circumferential direction on the rotary rack 31. Each developing device 32 is provided with a developing roller 33 in the vicinity of the photosensitive drum 21. A bias having the same polarity as the charging polarity of the photosensitive drum 21 is applied to the developing roller 33. The developing roller 33 charges the toner, which is a developer, and moves it to the electrostatic latent image on the surface of the photosensitive drum 21 to develop the electrostatic latent image. The toner is accommodated in a toner replenishing container 7 (see FIG. 1), conveyed to the location of the developing device 30 by the replenishing pipe 8, and replenished. When the toner is replenished, the replenishment pipe 8 extends to a position indicated by a two-dot chain line shown in FIG. The detailed configuration of the developing device 30 will be described later.

  As the toner used in the developing device 30, toner that is a one-component developer is used. The toner particles preferably have a high circularity in order to ensure high fluidity during stirring and conveyance. The average circularity of the toner is preferably 0.930 to 0.995 as measured by a flow type particle image analyzer FPIA manufactured by Sysmex Corporation. As an external additive for the toner, it is preferable to add a large amount of silica having a relatively large diameter that hardly changes in fluidity over time.

  The primary transfer unit 80 is provided with a primary transfer roller 81 that contacts the photosensitive drum 21 via the intermediate transfer belt 10. A primary transfer nip portion where the photosensitive drum 21 and the intermediate transfer belt 10 are in contact with each other is formed at a location where the primary transfer roller 81 is provided. The primary transfer roller 81 rotates according to the rotation of the intermediate transfer belt 10 by contacting the intermediate transfer belt 10 without having a driving device. The primary transfer roller 81 is applied with a primary transfer bias having a polarity opposite to the charged charge of the photosensitive drum 21 and the toner as necessary.

  The intermediate transfer belt 10 is composed of a single layer resin belt formed only of a synthetic resin such as polyimide or an elastic belt having a rubber layer laminated on the surface of such a synthetic resin, and is wound around a plurality of rollers. It is supported.

  As shown in FIG. 2, the drum cleaning device 70 is disposed further downstream of the primary transfer unit 80 along the rotation direction of the photosensitive drum 21. The drum cleaning device 70 includes a cleaning roller 72 and a discharge screw 73 inside the housing 71, and a cleaning blade 74 between the housing 71 and the photosensitive drum 21.

  The cleaning roller 72 and the cleaning blade 74 are urged by an elastic member such as a spring (not shown) and are pressed against the photosensitive drum 21. The cleaning roller 72 and the cleaning blade 74 extend in the axial direction of the photosensitive drum 21 and have substantially the same axial length as the photosensitive layer of the photosensitive drum 21. In order to efficiently perform cleaning, the cleaning roller 72 is driven by a driving device (not shown) so that the peripheral speed of the cleaning roller 72 is about 15 to 20% higher than the peripheral speed of the photosensitive drum 21. It is rotated in the direction opposite to the rotation direction of 21. After the toner image is transferred to the intermediate transfer belt 10 by the cleaning roller 72 and the cleaning blade 74, the toner remaining on the surface of the photosensitive drum 21 is removed and cleaned. The toner removed from the surface of the photosensitive drum 21 is once collected in the housing 71 and discharged to the outside by the discharge screw 73.

  Next, the detailed configuration of the developing device 30 will be described with reference to FIGS. 3 to 5 in addition to FIG. 3 is a perspective view of the developing device provided in the developing device, FIG. 4 is a left side view of the vertical section of the developing device, and FIG. 5 is a partial perspective view showing the vicinity of the remaining amount detecting means. Since the four color developing devices 32 have the same basic structure, the identification symbols for the respective colors such as “Y”, “M”, “C”, and “B” are omitted.

  The developing device 30 shown in FIG. 2 includes a developing device 32 shown in FIG. The developing device 32 includes a developing container 34. The developing container 34 has an elongated shape in the axial direction of the photosensitive drum 21, that is, in the depth direction of the paper surface of FIG. 2, and the longitudinal direction is arranged horizontally. When toner is supplied to the developing container 34 by the supply pipe 8 (see FIG. 2), the toner is supplied from a predetermined local area in the longitudinal direction.

  As shown in FIG. 4, a hopper portion 35 and a developing portion 36 are provided inside the developing container 34. The hopper 35 is provided with an agitating / conveying member 50 for agitating and conveying the toner, and the developing portion 36 is provided with a supply roller 37 for supplying the toner to the developing roller 33 with the axes thereof being horizontal. Yes. The detailed configuration of the stirring and conveying member 50 will be described later.

  The hopper portion 35 and the developing portion 36 are separated by a partition wall 38 in the developing container 34. The partition wall 38 is formed of a thin plate member made of metal, extends along the longitudinal direction of the developing container 34, and includes an opening 38 a at a location above the supply roller 37. A plurality of openings 38 a are provided in the longitudinal direction of the developing container 34, and toner can move between the hopper portion 35 and the developing portion 36 as indicated by white arrows in FIG. 4. Such a partition wall 38 can limit the amount of toner that moves between the hopper portion 35 and the developing portion 36. In the developing container 34, the toner is normally accommodated up to the two-dot chain line shown in FIG.

  The hopper 35 is a rotating member provided with a remaining amount detecting means 60 for detecting the remaining amount of toner as a developer and a cleaning member 62 at a location closer to the peripheral surface of the developing container 34 than the stirring and conveying member 50. 61.

  As shown in FIG. 5, the remaining amount detecting means 60 is provided at a side wall 34 a at the longitudinal end of the developing container 34. The remaining amount detecting means 60 is composed of an optical sensor using a light emitting diode (LED) as a light source, and includes a light emitting unit and a light receiving unit (not shown) and two light guides 60a having an optical path formed therein. I have.

  The light emitting part and the light receiving part are provided outside the side wall 34a of the developing container 34, and the two light guides 60a are provided so as to protrude into the hopper part 35 from the side wall 34a. The two light guides 60a are each provided with a light transmission surface 60b at the tip, and the two light transmission surfaces 60b are opposed to each other.

  The light emitted from the light emitting part travels inside the one light guide 60a, passes through the light transmitting surface 60b after the optical path is changed at a substantially right angle at the tip part, exits the light guide 60a, and stores toner. To reach the space. Then, when the light (broken arrow shown in FIG. 5) is not shielded by the toner, the light passes through the light transmitting surface 60b of the other light guide 60a and enters the inside thereof, and the optical path is changed in angle to a substantially right angle. Reach the light receiving part. In this way, the remaining amount detecting means 60 detects the remaining amount of toner in the developing container 34 by detecting the toner blocking the optical path in the space between the two light transmission surfaces 60b.

  As shown in FIG. 5, the rotating member 61 is provided at a location between the two light guides 60 a on the side wall 34 a of the developing container 34. The rotating member 61 includes a cleaning member 62 that protrudes toward the light transmission surface 60b of the remaining amount detection means 60, and rotates about an axis substantially orthogonal to the optical path between the light transmission surfaces 60b. A urethane resin sheet having a thickness of 100 μm is attached to the tip of the cleaning member 62 and corresponding to the light transmission surface 60b.

  Such a rotating member 61 causes the cleaning member 62 to appear in and out of the light transmitting surface 60b while rotating around an axis substantially orthogonal to the optical path between the light transmitting surfaces 60b. Then, the urethane resin sheet of the cleaning member 62 contacts the two light transmission surfaces 60b on the light emitting unit side and the light receiving unit side, and cleans these surfaces. Thereby, the toner adhering to the light transmission surface 60b is removed. When cleaning is completed, the rotating member 61 rotates to a position where the cleaning member 62 does not block the optical path of the remaining amount detection means 60 to secure an optical path between the two light transmission surfaces 60b, and the inside of the developing container 34. The remaining amount of toner can be detected.

  On the other hand, as illustrated in FIG. 4, the developing unit 36 includes an opening 39 at a location adjacent to the photosensitive drum 21. A developing roller 33 that is a developer carrier is disposed in the opening 39. One side of the developing roller 33 is located inside the developing unit 36, and the other side is exposed to the outside of the developing unit 36 and faces the photosensitive drum 21 that is an image carrier (see FIG. 2). The developing roller 33 is rotated clockwise in FIG. 4 by a driving unit (not shown).

  A regulating plate 40 is provided on the developing roller 33 on the downstream side in the rotational direction from the position inside the developing unit 36, that is, above the developing roller 33 in FIG. 4. The restricting plate 40 is formed of a thin film-like member made of synthetic resin or metal, and is provided so that one flat surface thereof is in contact with the developing roller 33 (see FIG. 4). Thus, the regulation plate 40 can form a thin toner layer on the surface of the developing roller 33 and quantitatively supply the toner to the photosensitive drum 21.

  Seal members 41 are provided on the inner side of the developing unit 36 at both ends in the axial direction of the developing roller 33. One seal member 41 is provided at each end of the developing roller 33 in the axial direction. The seal member 41 is made of felt, urethane, sponge, non-woven fabric, or the like, and is provided along the peripheral surface of the developing roller 33 so as to contact the surface of the developing roller 33 over a length of about half a circumference. The seal member 41 plays a role of preventing the leakage of toner from the gap between the both ends in the axial direction of the developing roller 33 and the developing container 34 to the outside.

  Next, a detailed configuration of the stirring and conveying member 50 disposed in the hopper 35 will be described with reference to FIGS. 6 to 8 in addition to FIG. 6 is a left side view of the agitating and conveying member in a vertical section, FIG. 7 is a front view of the agitating and conveying member, FIG. 8 is a front view of the agitating and conveying member similar to FIG. The thickness and the opening pattern are different. 7 and 8 are drawn with one of the two stirring blades included in the stirring and conveying member omitted.

  As shown in FIG. 6, the stirring and conveying member 50 includes a shaft portion 51 and a stirring blade 52.

  The shaft portion 51 has a rectangular parallelepiped shape extending in the longitudinal direction of the developing container 34, that is, the depth direction of the paper surface of FIGS. 4 and 6, and the cross-sectional shape thereof is substantially square. The agitating / conveying member 50 rotates about a central axis extending in the longitudinal direction of the shaft portion 51.

  As shown in FIG. 6, the stirring blade 52 is attached to a flat surface of the rectangular parallelepiped constituting the shaft portion 51 and extending in the longitudinal direction of the developing container 34. The agitating blade 52 is configured by forming a sheet of PET (polyethylene terephthalate) film having a thickness of 125 μm, and is fixed to the shaft portion 51 so as to extend radially outward from the shaft portion 51. As shown in FIG. 4, since the gap between the agitating / conveying member 50 and the inner wall of the developing container 34 is partially relatively narrow, when the agitating / conveying member 50 rotates, the agitating blade 52 contacts the inner wall of the developing container 34 at that location. Rotate to rub the inner wall.

  Further, the stirring blade 52 is provided on the shaft portion 51 by combining two stirring blades 52A and 52B in a stacked form. As shown in FIGS. 7 and 8, the two stirring blades 52 </ b> A and 52 </ b> B are provided with openings 53 having different patterns for each stirring blade. The opening 53 of the stirring blade 52 has a rectangular shape inclined from the fixed end side to the free end side of the stirring blade 52, that is, from the lower side to the upper side in FIGS. 7 and 8, and a plurality of openings 53 are provided in the longitudinal direction.

  As shown in FIG. 7, all of the plurality of openings 53 a of the stirring blade 52 </ b> A are inclined from the fixed end side (lower side in FIG. 7) toward the central portion with respect to the axial direction both end sides of the shaft portion 51. Yes. When the stirring blade 52A rotates with the rotation of the shaft portion 51, the toner moves from the both end portions in the axial direction toward the center portion along the inclination of the opening 53a. On the other hand, as shown in FIG. 8, all of the plurality of openings 53b of the stirring blade 52B are inclined from the fixed end side (lower side in FIG. 8) toward both end portions with respect to the central portion in the axial direction. When the stirring blade 52B rotates with the rotation of the shaft portion 51, the toner moves from the central portion in the axial direction toward both ends along the inclination of the opening 53b. The agitating and conveying member 50 is provided with one agitation blade 52 constituted by a pattern of these two types of openings 53 one by one.

  As shown in FIGS. 7 and 8, the stirring blade 52B has a shorter axial length than the stirring blade 52A. That is, in the region X shown in FIGS. 7 and 8, only the stirring blade 52A exists, and the stirring blade 52A is used to move from one end side (left side in the drawing) in the axial direction toward the inner side in the axial direction. Only works on toner. Accordingly, the region X provided on one end side in the axial direction of the agitating / conveying member 50 functions as a deflection unit that transports toner from the end side toward the inner side in the axial direction. On the other hand, an area Y shown in FIGS. 7 and 8 is an area where two stirring blades overlap each other, and the toner moves from both ends toward the central portion by the action of the stirring blades 52A. The toner moves from the central portion toward both ends by the action of 52B. Accordingly, the region Y functions as a stirring unit that uniformly disperses the toner in the axial direction of the stirring and conveying member 50.

  The deflection unit X is provided with a toner remaining amount detecting means 60 (see FIG. 5) in the developing container 34 and a toner supply port (not shown).

  On the other hand, the two stirring blades 52 have different radial lengths as shown in FIG. In other words, the stirring blade 52A arranged at the most upstream in the rotation direction of the stirring and conveying member 50 has a longer radial direction length than the stirring blade 52B arranged on the downstream side.

  As described above, in the developing device 30 that includes the stirring and conveying member 50 that rotates about the axis and conveys the toner in the developing container 34 toward the developing roller 33 while stirring, the stirring and conveying member 50 has a rotation center. And a sheet-like stirring blade 52 fixed to the shaft portion 51 so as to extend radially outward from the shaft portion 51, and at least one region of both end portions in the axial direction. Since the deflecting portion X that transports the toner inward in the axial direction from the portion side and the stirring portion Y that uniformly disperses the toner in the axial direction is provided in other regions, the developing blade 52 is developed by the action of the stirring blade 52. In the container 34, the amount of toner can be relatively reduced in the vicinity of the end portion in the longitudinal direction on the deflection portion X side, and the toner is uniformly stirred in the stirring portion Y that is a region such as the other central portion in the longitudinal direction. It can be moved. As a result, even when the toner replenishing port, the remaining amount detecting means 60 and the like are disposed locally in the developing container 34, the toner does not stay in these portions, and the developing container 34 is sufficiently long in the longitudinal direction. The toner can be dispersed. Therefore, it is possible to obtain the developing device 30 that can prevent the occurrence of image defects due to staying and deteriorated toner or toner shortage and capable of forming a high-quality image.

  Further, since the stirring blade 52A has a plurality of openings 53a inclined in the region corresponding to the deflection portion X from the fixed end side toward the free end side, by rotating the stirring blade 52A, the inclination direction of the opening 53a It is possible to move the toner along the line. As a result, the amount of toner can be relatively reduced in the vicinity of the end in the longitudinal direction in the developing container 34, and the toner can be uniformly stirred and moved in other regions such as the central portion in the longitudinal direction. be able to.

  Since a plurality of stirring blades 52 are provided in combination, it is possible to increase the amount of toner that can be moved per unit time as the stirring and conveying member 50 rotates. As a result, the agitating / conveying performance of the toner is improved, and a desired toner distribution in the developing container 34 can be obtained efficiently.

  Each of the plurality of stirring blades 52 includes a stirring blade 52A having the function of the deflecting unit X and the function of the stirring unit Y, and a stirring blade 52B having only the function of the stirring unit Y. Since the stirring and conveying member 50 includes at least one stirring blade 52A and 52B, the simple structure using the two stirring blades 52A and 52B deflects the entire region in the axial direction of the stirring and conveying member 50. Part X and stirring part Y can be constituted. Accordingly, the toner can be sufficiently dispersed in the longitudinal direction in the developing container 34 without the toner staying in a portion such as the toner replenishing port and the remaining amount detecting means 60, and the operation can be easily obtained.

  Each of the two stirring blades 52 has a plurality of openings 53 inclined from the fixed end side toward the free end side in a region corresponding to the stirring unit Y, and the direction in which the opening 53 is inclined for each stirring blade. Therefore, the toner can be moved along the inclination direction of the opening 53 by rotating each stirring blade 52. As a result, the toner can be easily moved in various longitudinal directions in the developing container 34. Therefore, the toner can be dispersed sufficiently efficiently in the longitudinal direction in the developing container 34.

  The two agitating blades 52A and 52B each have an opening 53a that is inclined from the fixed end side toward the central portion with respect to both axial end sides in the region corresponding to the stirring portion Y, and the axial center. The opening 53b is inclined toward both ends with respect to the part, and since the two kinds of stirring blades 52A and 52B are provided with at least one stirring and conveying member 50, one stirring blade 52A is provided. Thus, the toner can be moved to the central portion in the longitudinal direction in the developing container 34, and the toner can be moved to both ends by the other stirring blade 52B. As a result, the toner can be moved back and forth from both ends in the developing container 34 to the center, and from the center to both ends, and the toner can be efficiently stirred. Therefore, the action of dispersing the toner in the longitudinal direction in the developing container 34 can be improved.

  Further, since the stirring and conveying member 50 is provided with a plurality of stirring blades 52 stacked, the plurality of stirring blades 52 continuously rotate at short time intervals to stir the toner. As a result, the stirring force is increased as compared with the case where the stirring blades 52 are not stacked, and the toner can be easily moved along the longitudinal direction in the developing container 34. Therefore, it is possible to further enhance the action of dispersing the toner in the longitudinal direction in the developing container 34.

  In the present invention, since the developing device 30 is mounted on the printer 1, even when a toner replenishing port, a remaining amount detecting means 60, and the like are disposed locally in the developing container 34 of the developing device 30, The toner can be sufficiently dispersed in the longitudinal direction in the developing container 34 without the toner staying in the place, and the high-performance printer 1 capable of performing high-quality image formation can be obtained.

  Next, a detailed configuration of the developing device according to the second embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a front view of an agitating / conveying member of the developing device, FIG. 10 is a front view of an agitating / conveying member similar to FIG. 9, and the axial length and opening pattern of the agitating blades are different from those in FIG. 9 and 10 are drawn in a form in which one of the two stirring blades included in the stirring and conveying member is omitted. In addition, the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 8, and therefore the configuration common to the first embodiment is described in the drawings, and The description will be omitted.

  In the developing device according to the second embodiment, the agitating and conveying member 50 includes two agitating blades 52C each having openings 53c and 53d with patterns having different inclination directions as shown in FIGS. And 52D are stacked and combined to provide the shaft portion 51.

  As shown in FIG. 9, all of the plurality of openings 53c of the stirring blade 52C are inclined from the fixed end side (lower side in FIG. 9) toward one end portion of the shaft portion 51, that is, toward the right side. When the stirring blade 52C rotates with the rotation of the shaft portion 51, the toner moves from the left to the right along the inclination of the opening 53c. As shown in FIG. 10, all of the plurality of openings 53d of the stirring blade 52D are inclined from the fixed end side (lower side in FIG. 10) toward the other end of the shaft portion 51, that is, toward the left. When the stirring blade 52D rotates with the rotation of the shaft portion 51, the toner moves from right to left along the inclination of the opening 53d. The agitating and conveying member 50 is provided with one agitation blade 52 constituted by a pattern of these two types of openings 53 one by one.

  As shown in FIGS. 9 and 10, the stirring blade 52D has a shorter axial length than the stirring blade 52C. That is, in the region X shown in FIGS. 9 and 10, only the stirring blade 52C exists, and the stirring blade 52C is used to move from one end side in the axial direction (left side in the drawing) toward the inner side in the axial direction. Only works on toner. Accordingly, the region X provided on one end side in the axial direction of the agitating / conveying member 50 functions as a deflection unit that transports toner from the end side toward the inner side in the axial direction. On the other hand, an area Y shown in FIGS. 9 and 10 is an area where the two stirring blades overlap each other, and the toner moves from the left to the right by the action of the stirring blade 52C, so that the stirring blade 52D. As a result, the toner moves from the right to the left. Accordingly, the region Y functions as a stirring unit that uniformly disperses the toner in the axial direction of the stirring and conveying member 50.

  As described above, in each of the two stirring blades 52C and 52D, in the region corresponding to the stirring portion Y, all the openings are from the fixed end side to one end side in the axial direction or the other end portion. It is composed of openings 53c and 53d inclined toward one of the sides, and these two types of stirring blades 52C and 52D are provided with at least one stirring and conveying member 50, so that development is performed with one stirring blade 52C. The toner can be moved to one end side in the longitudinal direction in the container 34, and the toner can be moved to the other end side by another stirring blade 52D. Accordingly, the toner can be moved back and forth from the end in the longitudinal direction in the developing container 34, and the toner can be efficiently stirred. Therefore, the action of dispersing the toner in the longitudinal direction in the developing container 34 can be improved.

  Next, a detailed configuration of the developing device according to the third embodiment of the present invention will be described with reference to FIGS. 11 is a left side view of the vertical section of the stirring and conveying member, FIG. 12 is a front view of the stirring and conveying member, FIG. 13 is a front view of the stirring and conveying member similar to FIG. 12, and FIG. It is drawn by changing. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 8, the configuration common to the first embodiment is described in the drawings, and The description will be omitted.

  In the developing device according to the third embodiment, as shown in FIG. 11, the agitating and conveying member 50 is a combination of two agitating blades 52E and 52F with an angle difference of 90 degrees around the axis. The shaft portion 51 is provided. That is, the stirring blades 52E and 52F are respectively attached to different planes of the shaft portion 51 having a substantially square cross section. A stirring blade 52E is disposed on the downstream side in the rotational direction of the stirring and conveying member 50, and a stirring blade 52F is disposed immediately upstream thereof.

  As shown in FIGS. 12 and 13, the two stirring blades 52 </ b> E and 52 </ b> F are provided with openings 53 having different patterns for each stirring blade. The opening 53 of the stirring blade 52 has a rectangular shape, and a plurality of openings 53 are provided in the longitudinal direction.

  As shown in FIG. 12, all of the plurality of openings 53e of the stirring blade 52E have a rectangular shape extending straight from the fixed end side (the lower side in FIG. 12) toward the radially outer side without being inclined in the axial direction. Yes. When the stirring blade 52E rotates with the rotation of the shaft portion 51, the toner is dispersed without largely moving in the axial direction. As shown in FIG. 13, all of the plurality of openings 53f of the stirring blade 52F are inclined from the fixed end side (lower side in FIG. 13) toward one end of the shaft portion 51, that is, toward the right. When the stirring blade 52F rotates with the rotation of the shaft portion 51, the toner moves from the left to the right along the inclination of the opening 53f. The agitating and conveying member 50 is provided with one agitation blade 52 constituted by a pattern of these two types of openings 53 one by one.

  As shown in FIGS. 12 and 13, the stirring blade 52F has a shorter axial length than the stirring blade 52E. That is, the region Y shown in FIGS. 12 and 13 has only the stirring blade 52E, and functions as a stirring unit that uniformly disperses the toner in the axial direction of the stirring and conveying member 50 by the stirring blade 52E. On the other hand, an area X shown in FIGS. 12 and 13 is an area where two stirring blades overlap, and the toner is dispersed by the action of the stirring blade 52E. From one end side (left side in the figure) in the direction toward the inner side in the axial direction. Accordingly, the region X provided on one end side in the axial direction of the agitating / conveying member 50 functions as a deflection unit that transports toner from the end side toward the inner side in the axial direction.

  As described above, each of the two stirring blades 52 includes the stirring blade 52E that uniformly disperses the toner in the entire axial direction, and the stirring blade 52F that has only the function of the deflection unit X. Since at least one stirring blade 52E and 52F is provided for each of the stirring and conveying members 50, the simple structure using the two stirring blades 52E and 52F deflects the entire region in the axial direction of the stirring and conveying member 50. Part X and stirring part Y can be constituted. Accordingly, the toner can be sufficiently dispersed in the longitudinal direction in the developing container 34 without the toner staying in a portion such as the toner replenishing port and the remaining amount detecting means 60, and the operation can be easily obtained.

  Next, a detailed configuration of the developing device according to the fourth embodiment of the present invention will be described with reference to FIGS. 14 and 15. 14 is a left side view of the vertical section of the stirring and conveying member, and FIG. 15 is a front view of the stirring and conveying member. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 8, the configuration common to the first embodiment is described in the drawings, and The description will be omitted.

  In the developing device according to the fourth embodiment, the agitating / conveying member 50 includes only one agitating blade 52G in the shaft portion 51 as shown in FIG. The stirring blade 52G is provided with two different types of openings 53 as shown in FIG. The openings 53 of the stirring blade 52G have a quadrangular shape and are provided in the longitudinal direction.

  In the region X of the stirring and conveying member 50 shown in FIG. 15, the stirring blade 52G has a plurality of openings 53g. All the openings 53g are inclined from the fixed end side (the lower side in FIG. 15) toward one end of the shaft portion 51, that is, toward the right. When the stirring blade 52G rotates with the rotation of the shaft portion 51, the toner moves from the left to the right along the inclination of the opening 53g. Accordingly, the region X provided on one end side in the axial direction of the agitating / conveying member 50 functions as a deflection unit that transports toner from the end side toward the inner side in the axial direction.

  On the other hand, in the region Y of the stirring and conveying member 50, the stirring blade 52G has a plurality of openings 53h. All the openings 53h have a rectangular shape extending straight from the fixed end side (the lower side in FIG. 15) toward the radially outer side without being inclined in the axial direction. When the stirring blade 52G rotates with the rotation of the shaft portion 51, the toner is dispersed without largely moving in the axial direction. Accordingly, the region Y functions as a stirring unit that uniformly disperses the toner in the axial direction of the stirring and conveying member 50.

  The agitating and conveying member 50 includes only one agitating blade 52G configured by these two types of openings 53 patterns. Thus, even when the stirring and conveying member 50 includes only one stirring blade 52G, the action of the deflecting unit X and the stirring unit Y is the same as in the first to third embodiments. It is possible to obtain the effect.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the above-described embodiment, the printer 1 includes the rotary rack 31 in which the four developing devices 32 are arranged at equal intervals in the circumferential direction in the developing device 30 and the endless intermediate transfer belt 10 as an intermediate transfer member. Although it is an image forming apparatus for color printing, it may be a tandem color printing image forming apparatus or an image forming apparatus for monochrome printing that uses only black toner without using an intermediate transfer member. .

  Further, the openings 53a to 53h provided in each stirring blade 52 have a rectangular shape with rounded corners, a so-called oval shape including an oval shape, an oval shape, an oval shape, a triangular shape, and a slit shape. It doesn't matter. Even with a stirring blade having an opening having such a shape, it is possible to obtain the same operations and effects as in the first to fourth embodiments.

  The present invention can be used in all developing devices applicable to image forming apparatuses.

1 is a left side view of a schematic vertical section of a printer equipped with a developing device according to a first embodiment of the present invention. FIG. 2 is a partially enlarged vertical sectional view showing the periphery of the image forming unit in FIG. 1. FIG. 3 is a perspective view of a developing device provided in the developing device of FIG. 2. FIG. 4 is a left side view of a vertical section of the developing device shown in FIG. 3. It is a fragmentary perspective view which shows the remaining amount detection means periphery of FIG. It is a vertical cross-section left view of the stirring and conveying member shown in FIG. It is a front view of the stirring conveyance member shown in FIG. FIG. 7 is a front view of the same stirring and conveying member as in FIG. 7, and the axial length and opening pattern of the stirring blades are different from those in FIG. It is a front view of the stirring conveyance member of the developing device concerning a 2nd embodiment of the present invention. FIG. 9 is a front view of the same stirring and conveying member as in FIG. 9, and the axial length of the stirring blade and the opening pattern are different from those in FIG. 9. It is a vertical cross-section left side view of the stirring and conveying member of the developing device according to the third embodiment of the present invention. It is a front view of the stirring conveyance member shown in FIG. FIG. 12 is a front view of the same stirring and conveying member as in FIG. 12, and FIG. 12 is drawn by changing the rotation angle of the stirring and conveying member. It is a vertical cross-section left side view of the stirring and conveying member of the developing device according to the fourth embodiment of the present invention. It is a front view of the stirring conveyance member shown in FIG.

Explanation of symbols

1 Printer (image forming device)
DESCRIPTION OF SYMBOLS 20 Image formation part 21 Photosensitive drum 30 Developing apparatus 31 Rotary rack 32 Developing device 33 Developing roller 34 Developing container 35 Hopper part 36 Developing part 50 Stirring conveyance member 51 Shaft part 52A-52G Stirring blade 53a-53h Opening

Claims (10)

A developing container that contains toner, a developing roller that supplies toner to an image carrier on which an electrostatic latent image is formed, and a roller that rotates about the axis to convey the toner in the developing container toward the developing roller while stirring. In a developing device provided with a stirring and conveying member that
The stirring and conveying member includes a shaft portion serving as a rotation center and a sheet-shaped stirring blade fixed to the shaft portion so as to extend radially outward from the shaft portion, and at least one of both end portions in the axial direction. A developing device comprising: a deflection unit that transports toner from an end side toward an inner side in an axial direction in an area; and a stirring unit that uniformly disperses toner in the axial direction in another area.   The developing device according to claim 1, wherein the stirring blade has a plurality of openings inclined from a fixed end side toward a free end side in a region corresponding to the deflection unit.   The developing device according to claim 1, wherein a plurality of the stirring blades are provided in combination.   Each of the plurality of stirring blades is composed of a stirring blade having the function of the deflection unit and the function of the stirring unit, and a stirring blade having only the function of the stirring unit. The developing device according to claim 3, wherein at least one agitating and conveying member is provided.   Each of the plurality of stirring blades includes a stirring blade that uniformly disperses toner in the entire axial direction, and a stirring blade that has only the function of the deflecting unit, and these two types of stirring blades are used as the stirring transport member. The developing device according to claim 3, wherein at least one sheet is provided.   Each of the plurality of stirring blades has a plurality of openings that are inclined from the fixed end side toward the free end side in a region corresponding to the stirring unit, and each of the stirring blades has a pattern in which the inclination direction of the opening is different. The developing device according to claim 3, wherein the developing device is provided.   Each of the plurality of stirring blades is located in a region corresponding to the stirring portion from the fixed end side toward the central portion side with respect to the axial end portions, or toward the both end portions side with respect to the axial central portion. The developing device according to claim 6, wherein the developing device includes at least one of these two types of stirring blades.   In each of the plurality of stirring blades, in the region corresponding to the stirring unit, all the openings are directed from the fixed end side to one end side in the axial direction or the other end side. The developing device according to claim 6, wherein the developing device includes an inclined opening, and each of the two stirring blades includes at least one stirring / conveying member.   The developing device according to claim 1, wherein the stirring and conveying member includes the plurality of stirring blades stacked.   An image forming apparatus comprising the developing device according to claim 1.

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