JP2014071297A - Image forming unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To equalize an amount of developer dropping off from each of apertures into an image forming unit.SOLUTION: An image forming unit of the present invention includes: an image carrier; a developer carrier supplying developer to the image carrier; a developer accommodation part supplying the developer to the developer carrier; a feeding member feeding the developer to an end part of the developer accommodation part; a conveyance member positioned at the lower part of the feeding member in the vertical direction, provided longitudinally in the horizontal direction and conveying the developer in the horizontal direction; and a guide member provided so as to cover the periphery of the conveyance member and guiding the developer in the horizontal direction. The guide member includes a plurality of apertures from the upstream side to the downstream side in the conveyance direction of the developer, and the plurality of apertures are larger in opening area toward the downstream side in the conveyance direction of the developer.

Description

  The present invention relates to an image forming unit and an image forming apparatus that form an image by supplying a developer evenly.

  Conventionally, uniform toner replenishment in the image forming unit has been performed by a toner replenishing port, a rotating conveying member below it, and a guide member covering the conveying member. As an example of an image forming unit provided with such a guide member, there is a developing device and an image forming device described in Patent Document 1.

  The guide member of the developing device and the image forming apparatus of Patent Document 1 has a wall on the side surface, and the wall surface has a tapered shape in which the height of the wall surface decreases as it goes in the transport direction of the transport member.

JP2007-101718A

  In the above configuration, the toner amount in the longitudinal direction in the image forming unit may be biased to one side, and the toner amount may be insufficient on the other side. When the toner amount is biased, the image quality may be lowered.

  An image forming unit according to the present invention has been made to solve the above problems, and includes an image carrier, a developer carrier for supplying a developer to the image carrier, and the developer on the developer carrier. A developer containing portion for supplying the developer, a replenishing member for replenishing the developer to the end of the developer containing portion, and a vertically long lower portion of the replenishing member that is disposed in the horizontal direction. A transport member that transports the developer in the horizontal direction, and a guide member that is disposed so as to cover the periphery of the transport member and guides the developer in the horizontal direction, and the guide member transports the developer A plurality of openings from the upstream side toward the downstream side in the direction, and the opening areas of the plurality of openings increase toward the downstream side in the developer transport direction. The image forming apparatus of the present invention also has the same configuration as the image forming unit.

  With this configuration, it is possible to make the amount of the developer falling from the respective openings into the image forming unit uniform.

1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. 1 is a side sectional view showing an image forming unit according to a first embodiment of the present invention. 1 is a perspective view illustrating an image forming unit according to a first embodiment of the present invention. FIG. 3 is a perspective view illustrating a toner amount detection member of the image forming unit according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view of a main part showing a rotary shutter member of the image forming unit according to the first embodiment of the present invention. FIG. 3 is a perspective view illustrating a conveyance member and a guide member of the image forming unit according to the first embodiment of the present invention. FIG. 3 is a perspective view illustrating a conveyance member and a guide member of the image forming unit according to the first embodiment of the present invention. FIG. 3 is a side view illustrating a conveyance member and a guide member of the image forming unit according to the first embodiment of the present invention. It is sectional drawing which shows the opening part of the guide member of the image forming unit which concerns on 1st Embodiment of this invention. FIG. 3 is a schematic diagram illustrating toner distribution on a guide member of the image forming unit according to the first embodiment of the present invention. FIG. 6 is a schematic diagram illustrating an operation of a toner amount detection member of the image forming unit according to the first embodiment of the present invention. FIG. 6 is a schematic diagram illustrating an operation of a toner amount detection member of the image forming unit according to the first embodiment of the present invention. 3 is a time chart for detecting toner low and toner full in a toner amount detection member of the image forming unit according to the first embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a state where toner falls from an opening of the image forming unit according to the first embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a toner replenishment state in the image forming unit according to the first embodiment of the present invention. It is a perspective view which shows the conveyance member and guide member of an image forming unit which concern on 2nd Embodiment of this invention. It is sectional drawing which shows the conveyance member and guide member of the image forming unit which concern on 2nd Embodiment of this invention. It is a perspective view which shows the conveyance member and guide member of the image forming unit which concern on 3rd Embodiment of this invention.

  Hereinafter, an image forming unit and an image forming apparatus according to an embodiment of the present invention will be described.

[First embodiment]
First, an image forming unit and an image forming apparatus according to a first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus 100 according to the first embodiment.

  The image forming apparatus 100 in FIG. 1 is an apparatus capable of color printing. The image forming apparatus 100 includes four color image forming units 1K, 1Y, 1M, and 1C of K (black), Y (yellow), M (magenta), and C (cyan). Above these units, an exposure head 2 that forms an electrostatic latent image on the photosensitive drum 22 is provided with a certain gap. These are controlled by a control unit (not shown) of the image forming apparatus 100 to perform color printing and monochrome printing.

  A tray 3 is detachably provided at the bottom of the image forming apparatus 100. A medium 4 is stored in the tray 3. The medium 4 is transported by a paper feed roller 5 and a transport roller 6. In the conveyance path of the medium 4, the image forming units 1K, 1Y, 1M, and 1C are conveyed by the transfer belt 7 and the transfer belt 7 for conveying the medium toward the image forming units 1K, 1Y, 1M, and 1C. A transfer roller 32 for transferring the toner image formed by the image forming units 1K, 1Y, 1M, and 1C to the medium, a fixing device 8 for fixing the image transferred to the medium 4, and the medium 4 outside the apparatus. A transport roller 9 and a discharge roller 10 for transporting and discharging the paper, and a stacker cover 11 for holding the discharged medium 4 are installed. Further, a toner storage container 12 is provided above each of the image forming units 1K, 1Y, 1M, and 1C. In the toner storage container 12 as each developer container, four color toners K, Y, M, and C corresponding to the respective image forming units 1K, 1Y, 1M, and 1C are stored.

  Since the image forming units 1K, 1Y, 1M, and 1C and the toner storage container 12 have the same configuration, the K (black) image forming unit 1K and the toner storage container 12 will be described below. 2 is a sectional view showing the image forming unit 1K and the toner storage container 12, FIG. 3 is a perspective view showing the image forming unit 1K, and FIG. 4 is a perspective view showing the toner amount detecting member 16. As shown in FIG.

  In FIG. 2, the toner storage container 12 has an agitating member 14 for agitating the toner 13 as a developer and a rotatable shutter member 40 inside. The shutter member 40 has an opening 40a. The opening 40a is connected to the toner supply port 15 of the image forming unit 1K. On the other hand, the image forming unit 1K has a toner replenishing port 15, a rotary shutter member 15a, a toner amount detecting member 16, stirring members 17 and 18 for stirring the toner, and an electrostatic latent image formed on the photosensitive drum 22 with toner. A developing roller 20 that is a developer carrying member for developing the toner, and a toner supply roller 19 for supplying toner 13 to the developing roller 20.

  Here, a diffusion mechanism 101 is provided between the toner supply roller 19 and the toner supply port 15, and a toner amount detection member 16 is disposed between the diffusion mechanism 101 and the toner supply roller 19. A diffusion mechanism 101 is provided vertically below the toner supply port 15, and a toner amount detection member 16 and a toner supply roller 19 are provided vertically below the diffusion mechanism 101.

  Here, the rotary shutter member 15a is a replenishing member that replenishes the toner 13 into the image forming unit 1K. The rotary shutter member 15a has a toner chamber 151a (see FIG. 5) partitioned by ribs. The rotary shutter member 15 a shields and supplies the toner 13 in the toner storage container 12. That is, the rotary shutter member 15a shields the toner supply port 15 in a stationary state, but rotates to take the toner 13 in the toner storage container 12 into the toner chamber 151a and into the lower image forming unit 1K. Supply.

  The toner amount detection member 16 is a device for detecting the toner amount based on the rotation state of the paddle 16a. The toner amount detection member 16 includes a rotatable planar paddle protruding in the radial direction of the rotation shaft. The toner amount detection member 16 is set such that a center of gravity is set at a radial end portion of the rotation shaft, and an inertia moment is generated by rotation due to its own weight.

  The developing blade 21 is a member for thinning the toner 13 supplied to the developing roller 20. The developing blade 21 is placed in contact with the developing roller 20. The photosensitive drum 22 as an image carrier is placed in contact with the developing roller 20. Further, a charging roller 23 and a cleaning blade 24 are placed in contact with the photosensitive drum 22. A waste toner conveying member 25 for discharging the toner 13 scraped by the cleaning blade 24 is installed below the cleaning blade 24.

  In FIG. 3, reference numeral 29 denotes a reflection plate installed at the end of the toner amount detection member 16. A sensor 30 that detects the position of the reflecting plate 29 is installed on the main body side at the position facing the reflecting plate 29 and at the lowest point of the rotation locus. The sensor 30 includes a light emitting unit 301 and a light receiving unit 302. Further, as shown in FIG. 4, a rotating member 31 is installed as a driving source for the toner amount detecting member 16. The toner amount detection member 16 includes a paddle 16a and a shaft portion 16b. The paddle 16a and the shaft portion 16b are configured to rotate integrally, and a reflecting plate 29 is arranged at one end side in the axial direction of the shaft portion 16b so as to face the sensor 30 when the paddle 16a is vertically below. Be placed. The paddle 16 a of the toner amount detection member 16 rotates in contact with the protrusion 311 of the rotation member 31. Further, the shaft of the toner amount detection member 16 is inserted into the rotating member 31 so as to have a gap. Therefore, the toner amount detection member 16 is supported so as to be freely rotatable with respect to the rotation member 31.

  FIG. 5 is an enlarged view of the toner supply port 15 in FIG. As described above, the rotary shutter member 15a shields the toner replenishing port 15 in a stationary state and rotates to take in the toner 13 in the toner storage container 12 into the toner chamber 151a and to lower the image forming unit 1K. Supply in. Small gaps ΔL1 and ΔL2 are set between the rotary shutter member 15a and the cover 35.

  Next, a toner replenishment system and a toner transport system will be described.

  As shown in FIG. 2, a diffusion mechanism 101 is provided vertically below the rotary shutter member 15 a in the toner supply port 15. The diffusion mechanism 101 is a device for uniformly diffusing the toner 13 supplied from the toner supply port 15 in the longitudinal direction in the image forming unit 1K. The diffusion mechanism 101 is constituted by a screw conveyor. The diffusion mechanism 101 is disposed over the entire length in the longitudinal direction of the image forming unit 1K. Specifically, the diffusing mechanism 101 includes a conveyance member 26, a guide member 27, and a drive motor 28 attached to the main body device side.

  The conveying member 26 is configured by a spiral screw member that conveys the toner 13. The guide member 27 is a member that is formed so as to cover the conveying member 26 and restricts the movement of the toner. The guide member 27 is formed in a groove shape with a U-shaped cross section so as to cover the periphery of the transport member 26. By making the cross-sectional shape of the guide member 27 U-shaped, the toner 13 is transported through the guide member 27 when the transport member 26 that is a screw member rotates.

  The area of the toner replenishing port 15 is set to be as small as possible. This is to reduce the contamination of the surroundings by the toner 13 scattered from the toner supply port 15 when the storage container 12 is replaced. In the present embodiment, as shown in FIG. 3, the rotary shutter member 15a is installed at one end in the longitudinal direction of the image forming unit 1K. This is to prevent the toner 13 from being soiled when removed. Specifically, when the image forming unit 1K is detachable from the toner storage container 12 in the longitudinal direction, the toner replenishing port 15 is located on the upstream side in the mounting direction and on the downstream side in the removal direction. By arranging in the position, the stroke until the toner supply port 15 is guided outside the apparatus can be shortened. Therefore, for example, it is possible to reduce the adhesion of toner to the outer periphery of the toner storage container 12 near the toner supply port 15. The same applies to the case where the toner storage container 12 is attached to and detached from the image forming unit 1K in the longitudinal direction.

  In this embodiment, the conveying member 26 is configured by a spiral rotating body (screw member) having a rotatable shaft. The spiral traveling direction by the rotation of the conveying member 26 is set so that the spiral winding direction and the rotation direction are directed from the end where the rotary shutter member 15a is installed to the other end, that is, in the direction of the arrow 26a in FIG. ing. The conveying member 26 is synchronized in driving with the rotary shutter member 15a which is a replenishing member.

  As shown in FIG. 6, the guide member 27 is formed of a receiving portion wall surface 270 disposed at a position facing the rotary shutter member 15 a constituting the toner supply port 15 and a guide member wall surface 272 facing the receiving portion wall surface 270. And a plurality of openings 27a, 27b, 27c, and 27d disposed on the downstream side of the receiving portion 273 in the toner conveying direction (longitudinal direction) of the guide member 27. Further, the guide member 27 includes a wall surface portion constituted by a guide member wall surface 271 as a first wall surface and a guide member wall surface 272 as a second wall surface formed between the opening 27a and the opening 27b, Consists of a wall surface portion formed by guide member wall surfaces 271 and 272 formed between the opening portion 27b and the opening portion 27c, and guide member wall surfaces 271 and 272 formed between the opening portion 27c and the opening portion 27d. Wall surface portion. In the present embodiment, four openings 27 a, 27 b, 27 c, 27 d are provided, but the number of openings is set according to various conditions such as the length dimension of the guide member 27. For this reason, the number of openings may be 2, 3 or 5 or more.

  In this embodiment, since the number of openings is four, each of the four openings 27a, 27b, 27c, and 27d has about 25% of the total toner replenishment amount (specifically, a range of 20 to 30%). The width and length are set so that the can fall. Specifically, the openings 27a, 27b, 27c, and 27d are set at intervals of dimensions La, Lb, Lc, and Ld in the longitudinal direction of the guide member 27. In this embodiment, La = Lb = Lc = 7.5 (mm). Note that it is necessary to drop all the toner 13 to be transported at the final opening in the transport direction (27d in the present embodiment). For this reason, the longitudinal dimension Ld of the final opening 27d is made wider than others (Ld = 20 mm).

  Further, portions of the guide member 27 other than the openings 27a, 27b, 27c, and 27d (between the openings 27a and 27b, between the openings 27b and 27c, and between the openings 27c and 27d). 9), the height of the guide member wall surfaces 271 and 272 between the openings 27a, 27b, 27c, and 27d is set to a conveying member as shown in FIG. The height h from the rotation center 26 a of the 26 is set to be equal to or greater than the rotation radius R of the conveying member 26. In this embodiment, h = 1.5R. The guide member wall surface 271 as a wall surface is a wall surface formed between the openings 27a, 27b, 27c, and 27d, and the guide member wall surface 271 and the openings 27a, 27b, 27c, and 27d are the transport member 26. Is formed on the side of the upper portion in the vertical direction facing the rotational direction.

  The opening areas of the openings 27a, 27b, 27c, and 27d are set as follows.

  FIG. 8 is a side view of the guide member 27 as viewed from a direction perpendicular to the longitudinal direction of the guide member 27. FIG. 9 is a cross-sectional view taken along lines AA, BB, CC, DD, EE, FF, GG, HG, I-H shown in FIG. It is sectional drawing corresponding to each cross section of I cross section. 9 (a) is an AA cross section, FIG. 9 (b) is a BB cross section, FIG. 9 (c) is a CC cross section, FIG. 9 (d) is a DD cross section, and FIG. 9 (e) is a cross section. Corresponding to the EE cross section, the FF cross section, the GG cross section, the HH cross section, and the II cross section have the same cross sectional shape as the EE cross section shown in FIG.

  In FIG. 9, the rotation direction of the conveying member 26 is 26R. In FIG. 9A, among the transport members 26 divided by the horizontal line 26x passing through the rotation center of the transport member 26, an opening is formed on the upstream side in the lower half rotational direction 26R, that is, on the + X side in FIG. A portion 27a is provided. Similarly, an opening 27b (see FIG. 9B), an opening 27c (see FIG. 9C), and an opening 27d (see FIG. 9D) are provided on the + X side. In this embodiment, since the toner is transported in the transport state as shown in FIG. 10A by rotating the transport member 26 to the + X side, the openings 27a, 27b, 27c, and 27d are guided. Although it is provided on the member wall surface 271 side, when the transport member 26 is rotated to the −X side, the toner is transported in the transport state as shown in FIG. Openings 27a, 27b, 27c, and 27d may be arranged on the side. Returning to FIG. 9, in the present embodiment, the opening ends of the openings 27a, 27b, 27c, and 27d are positions at angles θa, θb, θc, and θd (see FIGS. 9A to 9D), respectively. It is formed to become. In this embodiment, θa = 45 °, θb = 60 °, θc = 90 °, and θd = 180 °. These are set so that θa <θb <θc <θd. Therefore, the opening areas Aa, Ab, Ac, and Ad of the openings 27a, 27b, 27c, and 27d have a relationship of Aa <Ab <Ac <Ad. That is, the plurality of openings 27a, 27b, 27c, and 27d are set so that the opening area increases toward the downstream side in the transport direction of the toner 13 as the developer. In addition, the EE line part, FF line part, GG line part, HH line part, and II line part of FIG. 8 do not have an opening part like FIG.9 (e), It is blocked.

  Further, when the characteristics of the target toner 13 are different, for example, when the fluidity is high, the distribution of the toner 13 in the guide member 27 is different as shown in FIG. However, as long as the above-described relationship of Aa <Ab <Ac <Ad is satisfied, the dimensions of the longitudinal lengths La, Lb, Lc, and Ld may be changed as appropriate.

  Furthermore, the interval between the openings from the first opening 27a to the final opening 27d is set to be approximately equal. In the present embodiment, when the distance between the opening 27a and the opening 27b is Lab, the distance between the opening 27b and the opening 27c is Lbc, and the distance between the opening 27c and the opening 27d is Lcd, each opening The intervals Lab, Lbc, and Lcd of 27a, 27b, 27c, and 27d are set to 80 mm (Lab = Lbc = Lcd = 80 mm). The transport states of the toner 13 transported by the transport member 26 are stabilized by the intervals Lab, Lbc, and Lcd. While the toner 13 is being transported by the transport member 26, the toner 13 is partially dropped at the openings 27a, 27b, and 27c, and the flow is branched. When a part of the toner transported by the transport member 26 falls due to the opening, the transport state of the toner in the guide member 27 remaining without being dropped at the opening is temporarily disturbed. For example, since the toner transport state in the guide member 27 is temporarily disturbed after the toner has dropped at the opening 27a, the guide member wall surface 271 and the guide member wall surface formed between the opening 27a and the opening 27b. The conveyance state of the toner 13 is stabilized while being conveyed by the conveyance member 26 by 272. Thereafter, the toner is dropped again at the opening 27b on the downstream side of the opening 27a in the direction 26a in which the toner is conveyed. By repeating this also in the openings 27c and 27d on the downstream side, the amount of toner falling from each opening can be stabilized.

  In this embodiment, Lab = Lbc = Lcd, but it is more preferable to set so that Lab <Lbc <Lcd as shown in FIG. Usually, when the amount of the toner 13 is reduced, the weight of the toner to be transported becomes light and the toner transport state is likely to be disturbed, so that the time (distance) required to stabilize the toner transport state is increased. Therefore, the intervals between the openings 27a, 27b, 27c, and 27d are set so that Lab <Lbc <Lcd as shown in FIG. That is, the distances Lab, Lbc, and Lcd of the guide member 27 surrounded by the guide member wall surfaces 271 and 272 are set to distances necessary for stabilizing the toner transport state. Thereby, the toner conveyance state can be stabilized and the toner can be dropped at the openings 27a, 27b, 27c, and 27d.

  The drive motor 28 is a drive source for rotationally driving the transport member 26. The drive motor 28 is connected to one end of the diffusion mechanism 101 in a state of being coupled to the transport member 26. The drive motor 28 is connected to the control unit and controlled by the control unit.

[Operation]
The image forming apparatus 100 configured as described above operates as follows.

In FIG. 1, upon receiving a print command from the control unit, the medium 4 is separated one by one by a paper feed roller 5 and conveyed to a transfer belt 7 by a conveyance roller 6. Further, the image forming units 1K, 1Y, 1M, and 1C are developed by a development process described later, and the toner 13 is transferred onto the medium 4 conveyed on the transfer belt 7 by the transfer roller 32. The medium 4 to which the toner 13 has been transferred passes through the fixing unit 8 to fix the toner 13, and is then discharged and held on the stacker cover 11 by the transport roller 9 and the discharge roller 10.

  Here, the developing process of the image forming units 1K, 1Y, 1M, and 1C will be described with reference to FIG. 2. However, since the image forming units 1K, 1Y, 1M, and 1C have the same configuration, the image forming unit 1K of K (black) is used. Only the other image forming units 1Y, 1M, and 1C will be omitted. In response to a print command from the control unit, the toner supply roller 19 is rotated in the direction of 19R by the drive source 1 (not shown), and the toner 13 is supplied to the developing roller 20 that rotates in the direction of 20R. At this time, the stirring members 17 and 18 also rotate in the directions of 17R and 18R, respectively, and search for the toner 13. The toner 13 supplied to the developing roller 20 is formed into a thin layer by the developing blade 21 and is charged. On the other hand, the surface of the photosensitive drum 22 rotating in the direction of the arrow 22R is charged by the charging roller 23. Then, it is exposed by the exposure head 2 to form an electrostatic latent image on the photosensitive drum 22. When the toner 13 on the developing roller 20 moves to the latent image, the exposed portion is developed. This development is transferred to the medium 4 as described above, but the toner 13 remaining on the photosensitive drum 22 is scraped off by the cleaning blade 24, conveyed by the waste toner conveying member 25, and discharged to the outside. . At this time, the conveying member 26 receives power from the drive motor 28 described above, and always rotates in the direction of the arrow 26R when the image forming unit 1K is driven.

  Next, operations of the toner amount detection member 16 and the toner supply system will be described.

  First, the operation of the toner amount detection member 16 will be described. As shown in FIG. 11A, the rotating member 31 is rotated at the rotation period T in the same 16R direction as the toner amount detecting member 16 by a driving source (not shown). The toner amount detection member 16 positioned at the lowest point is rotated so as to be pushed up from the lowest point to the highest point when the protrusion 311 of the rotation member 31 having the rotation period T contacts the paddle 16a. As a result, the toner amount detection member 16 reaches the highest point after the elapse of T / 2 as shown in FIG. Since the toner amount detection member 16 has a center of gravity at the end in the radial direction of the rotation axis, after reaching the highest point, the toner amount detection member 16 falls while rotating to its lowest point by its own weight as shown in FIG. .

  At this time, as shown in FIG. 12A, when the amount of toner 13 in the image forming unit 1K is small (in the case of toner low), the resistance of the toner 13 received by the toner amount detection member 16 is small. That is, when the position of the toner upper surface 34a is lowered, the toner amount detection member 16 hardly receives the resistance of the toner 13. Therefore, the toner amount detection member 16 falls to its lowest point due to its own weight, and reaches the lowest point earlier than the protrusion 311.

  On the other hand, when the amount of the toner 13 in the image forming unit 1K is sufficient, the toner amount detection member 16 may drop by its own weight to the lowest point due to the resistance of the toner 13 as shown in FIG. Can not.

  When the toner amount detection member 16 is positioned at the lowest point, the reflection plate 29 that rotates together with the toner amount detection member 16 is also positioned at the lowest point. And since sensor 30 is also installed in the lowest point of the rotation locus of reflector 29, sensor 30 detects reflector 29. That is, light emitted from the light emitting unit 301 of the sensor 30 is reflected by the reflecting plate 29, and the reflected light is received by the light receiving unit 302. Accordingly, the position of the toner amount detection member 16 can be detected, and it is detected that the toner amount detection member 16 is positioned at the lowest point.

  The sensor 30 detects the stay time at the lowest point of the toner amount detection member 16, and detects the toner low when the stay time T1 is longer than a preset time Tlow as shown in FIG. To do.

  When toner low is detected, the control unit issues a toner replenishment command. Accordingly, the stirring member 14 and the rotary shutter member 15a are rotated in the directions of arrows 14R and 15R, respectively, by a drive source (not shown). The toner 13 taken into the toner chamber 151 a of the rotary shutter member 15 a falls on the guide member 27.

  At this time, the conveying member 26 is also rotated. The toner 13 dropped on the guide member 27 is transported in the direction of the arrow 26a by the transport member 26. At this time, the toner 13 is conveyed in a distribution as shown in FIG.

  When the toner 13 reaches the first opening 27a by the conveying member 26, it is determined by the opening angle θa and the opening area Aa of the first opening 27a as shown in FIGS. 14 (a) and 15 (a). A proportion of the toner 13a1 falls from the opening 27a into the image forming unit 1K. In this embodiment, since the number of openings is 4, the opening of the first opening 27a is such that about 25% (20 to 30%) of the toner 13 falls from the opening 27a. An angle θa and an opening area Aa are set.

  Accordingly, about 75% (70 to 80%) of the toner 13a2 of the total toner replenishment amount passes through the opening 27a without dropping, and is conveyed to the second opening 27b.

  In the second opening portion 27b, as shown in FIGS. 14B and 15B, about 25% (20 to 30%) of the entire toner replenishment amount depending on the opening angle θb and the opening area Ab of the opening portion 27b. ) Falls in the toner 13b1. That is, the same amount of toner 13 that has fallen from the first opening 27a falls from the second opening 27b.

  As a result, about 50% (40 to 60%) of the toner 13b2 of the total toner replenishment amount passes through the opening 27b without dropping and is conveyed to the third opening 27c.

  These are repeated up to the fourth opening 27d, and the toner falls evenly from the four openings 27a, 27b, 27c, 27d.

  In this way, as shown in FIG. 15C, an equal amount of toner 13 is supplied into the image forming unit 1K from each opening. Then, as shown in FIG. 15D, the toner remaining amount detecting member 16 is uniformly stirred.

  Here, as shown in FIG. 10A, the toner 13 in the guide member 27 is conveyed in a distribution due to the rotation of the conveying member 26. This distribution is distributed in the openings 27a, 27b, 27c, and 27d. Different. That is, when a part of the toner 13 falls in the openings 27a, 27b, and 27c, the toner is not temporarily transported as shown in FIG. For this reason, it is necessary to return the toner distribution to the toner distribution state as shown in FIG.

  Then, it takes time to stabilize the toner conveyance state in the guide member 27, that is, to restore the toner distribution state as shown in FIG. For this reason, the space between the four openings 27a, 27b, 27c, and 27d is covered with the guide member wall surfaces 271 and 272. In the regions of the guide member wall surfaces 271 and 272, the toner conveyance state in the guide member 27 is stabilized.

  On the downstream side where the amount of the toner 13 in the guide member 27 decreases, it may take a long time to stabilize the toner conveyance state. In this case, as shown in FIG. 7, the openings 27a, 27b, 27c, and 27d are arranged so that the distance between the openings 27a, 27b, 27c, and 27d increases as the distance from the toner supply port 15 increases. To do. As a result, the toner can be conveyed to the next openings 27b, 27c, and 27d in a stable state of the toner in the guide member 27.

  As a result, the toner 13 drops from the openings 27a, 27b, 27c, and 27d by a certain amount, and is uniformly deposited in the image forming unit 1K. Then, the replenished toner 13 is uniformly deposited in the image forming unit 1 </ b> K, so that the toner amount detection member 16 receives pressure from the toner 13. As a result, the toner amount detection member 16 gradually rotates in synchronism with the rotation member 31 without falling by its own weight. The stay time T2 at the lowest point of the toner amount detection member 16 from the start of replenishment becomes shorter as the amount of accumulated toner increases. Then, as shown in FIG. 13B, when the stay time T2 becomes shorter than the set time Tlow, the toner full (toner interface 34b increased in FIG. 12B) is detected.

  After the toner full detection, the control unit issues a stop command for the agitating member 14 and the rotary shutter member 15a to a drive unit (not shown), and stops the replenishment / conveying operation. At this time, as shown in FIG. 5, by setting minute gaps ΔL1 and ΔL2 between the rotary shutter member 15a and the cover 35, the toner 13 passes between the gaps ΔLl and ΔL2 when the rotary shutter member 15a is stopped. Therefore, the toner 13 in the toner storage container 12 is held without falling.

  In the present embodiment, the gaps ΔLl and ΔL2 are set to 0.05 mm. The gaps ΔLl and ΔL2 may be set in the range of 0.03 to 0.3 mm.

[effect]
As described above, a plurality of openings 27 a, 27 b, 27 c, and 27 d having different opening areas are provided in the guide member 27 provided around the transport member 26, thereby causing the deviation of the toner 13 in the guide member 27. It is possible to prevent the deviation of the toner dropping position and amount. Therefore, it is possible to equalize the amount of toner 13 that falls from the respective openings 27a, 27b, 27c, and 27d into the image forming unit 1K.

  Further, as shown in FIG. 7, the distance between the openings 27a, 27b, 27c, and 27d is set so as to increase as the distance from the rotary shutter member 15a increases, so that the toner can be transported more stably. The parts 27a, 27b, 27c, and 27d are conveyed, and variation in the amount of drop due to fluctuations in toner distribution can be reduced. Therefore, the toner 13 can be replenished without being biased in the longitudinal direction in the image forming unit 1K, and deterioration in image quality due to insufficient toner amount can be prevented.

  Further, since the toner 13 is evenly distributed in advance by the conveying member 26 and the guide member 27, a stirring member such as a circulation mechanism is not required inside the developing device, so that deterioration of the toner 13 due to excessive stirring can be reduced. Therefore, it is possible to prevent a reduction in image quality.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The overall configuration of the image forming apparatus according to the present embodiment is substantially the same as that of the image forming apparatus 100 according to the first embodiment. Therefore, components having the same configuration are denoted by the same reference numerals and description thereof is omitted. Also, description of the same operations and effects as those of the image forming apparatus 100 of the first embodiment will be omitted.

  FIG. 16 shows the configuration of the toner conveying unit of the second embodiment. In the first embodiment, as shown in FIG. 6, the upper openings 27a ', 27b', 27c ', 27d' located above the openings 27a, 27b, 27c, 27d are opened together with the openings 27a, 27b, 27c, 27d. Thus, the openings 27a, 27b, 27c, and 27d are formed in a substantially U-shape, but in this embodiment, the openings 27a, 27a, 27b, 27c, and 27d may be formed in a square shape. FIG. 17 is a cross-sectional view of the first opening 27a taken along the line AA. The surface 271bl at the lower end in the direction of gravity of the wall surface 271b sharing the surface with the wall surface 271 is set at the intersection of the horizontal line from the rotation center of the transport member 26 and the guide member 27, that is, at a position higher than the rotation outer diameter R of the transport member 26. The wall surface 271b has the same configuration in the openings 27b, 27c, and 27d other than the opening 27a.

  Other configurations are the same as those in the first embodiment, and are omitted.

  In the first embodiment, since the wall surface 27l located above the openings 27a, 27b, 27c, and 27d is opened together with the openings 27a, 27b, 27c, and 27d, the openings 27a, 27b, 27c, and 27d are opened. In the sections 27ab, 27bc, and 27cd separated by, the strength decreases as the opening angle θ increases.

  On the other hand, in the second embodiment, a part of the wall surface 271a to be opened is shared with the wall surface 271 outside the opening, so that the strength of the guide member 27 can be increased. In addition, by setting the surface 271bl in the weight direction of the wall surface 271b to a position higher than the conveying member rotation outer diameter R, the rotation of the conveying member 26 does not affect the circulation of the toner 13 in the guide member 27, and thus the guidance The toner distribution in the member 27 is not affected. Therefore, similarly to the first embodiment, the amount of toner 13 falling into the developing device from each opening can be made uniform, and the toner 13 can be replenished uniformly in the longitudinal direction in the developing device. Therefore, it is possible to prevent a reduction in image quality.

[Third embodiment]
Next, a third embodiment of the present invention will be described. The overall configuration of the image forming apparatus according to the present embodiment is substantially the same as that of the image forming apparatus 100 according to the first embodiment. Therefore, components having the same configuration are denoted by the same reference numerals and description thereof is omitted. Also, description of the same operations and effects as those of the image forming apparatus 100 of the first embodiment will be omitted.

  In the first and second embodiments, the driving source of the conveying member 26 is driven by the driving source 1 of the image forming unit. However, in the third embodiment, the driving source of the conveying member 26 is the stirring member 14. And the driving source 2 for driving the rotary shutter member 15a. The conveying member 26 is synchronized in driving with the photosensitive drum 22 which is an image carrier.

  Other configurations are the same as those in the first and second embodiments, and thus are omitted.

  As in the first embodiment, when the toner amount detection member 16 detects toner low, a toner replenishment command is issued, and the agitating member 14, the rotary shutter member 15 a, and the conveying member 26 are respectively set to 14 R, 15 R, and 26 R by a driving source (not shown). Rotate in the direction to replenish toner 13 in the developing device. When the toner amount detection member 16 replenishes toner 13 sufficient for toner full detection, the toner full is detected, and the agitating member 14, the rotary shutter member 15a, and the conveying member 26 are stopped by the drive source 2 (not shown). The toner 13 in the middle of conveyance is held inside. Thereafter, when the toner 13 is consumed and the toner amount detection member 16 detects toner low again, a toner replenishment command is issued, and the agitating member 14, the rotary shutter member 15a, and the conveying member 26 are driven by the drive source 2 (not shown). At this time, since the toner 13 is held in the guide member 27 as shown in FIG. 18B, the toner 13 starts to fall simultaneously from all the drop openings.

  Since other operations are the same as those in the first embodiment, a description thereof will be omitted.

[effect]
In the first embodiment, when the toner replenishment command is issued, the toner 13 is not held in the guide member 27 as shown in FIG. There is a time difference until the toner 13 starts to fall. In other words, the opening closer to the replenishment roller 15 has a shorter time for the toner 13 to start dropping from the start of replenishment, and the longer the opening, the longer the time.

  On the other hand, the toner 13 is held in the guide member 27 at the start of the second and subsequent toner replenishment by synchronizing the switching of driving / stopping of the agitating member 14, the rotary shutter member 15a, and the conveying member 26 as in the third embodiment. Is done. As a result, the toner 13 starts to fall simultaneously from all the drop openings, so that the accuracy of detecting the remaining amount of toner is prevented from being lowered and the toner can be supplied more evenly. Therefore, the toner 13 can be replenished uniformly in the longitudinal direction in the developing device, and the deterioration of the image quality can be prevented.

[Modification]
The present invention relates to an image forming unit, but can be applied to an image forming apparatus used for a copying machine, an LED printer, a laser beam printer, a facsimile, an MFP, and the like.

  1K, 1Y, 1M, 1C: image forming unit, 2: exposure head, 3: tray, 4: medium, 5: paper feed roller, 6: transport roller, 7: transfer belt, 8: fixing device, 9, 10: Discharge roller, 12: toner storage container, 13: toner, 14: stirring member, 15: toner supply port, 15a: rotating shutter member, 16: toner amount detecting member, 17, 18: stirring member, 19: toner supply roller, 20: developing roller, 21: developing blade, 22: photosensitive drum, 23: charging roller, 24: cleaning blade, 25: waste toner conveying member, 26: conveying member, 27: guide member, 27a, 27b, 27c, 27d: Opening portion, 28: drive motor, 29: reflector, 30: sensor, 301: light emitting portion, 302: light receiving portion, 31: rotating member, 311: protrusion, 40: shutter member, 40a: open Parts, 100: image forming apparatus, 101: diffusion mechanism.

Claims (13)

An image carrier;
A developer carrier for supplying a developer to the image carrier;
A developer container for supplying the developer to the developer carrier;
A replenishment member for replenishing the developer to an end of the developer accommodating portion;
A conveying member that is positioned in the lower vertical direction of the replenishing member and that is long in the horizontal direction and conveys the developer in the horizontal direction;
A guide member disposed so as to cover the periphery of the transport member and guiding the developer in a horizontal direction;
The guide member has a plurality of openings from the upstream side toward the downstream side in the transport direction of the developer,
The image forming unit according to claim 1, wherein an opening area of the plurality of openings increases toward a downstream side in the developer transport direction.   The image forming unit according to claim 1, further comprising a wall surface between the plurality of openings.   The image according to claim 1, wherein at least one of the heights of the wall surfaces formed between the openings on the side surfaces of the guide member is higher than the rotational outer diameter of the transport member. Forming unit. The opening is located below a horizontal line perpendicular to the direction of gravity from the rotation center of the transport member,
4. The image forming unit according to claim 1, wherein the image forming unit has an opening angle downward from an intersection of a horizontal line from the rotation center of the conveying member and the guide member. 5.   The image forming unit according to claim 4, wherein the opening angle is greater than 0 ° and 180 ° or less.   The image according to any one of claims 1 to 5, wherein the opening is located on the upstream side in the rotation direction of the lower half of the transport member divided by a horizontal line from the rotation center of the transport member. Forming unit.   The image forming unit according to claim 1, wherein an opening angle of the plurality of openings increases toward a downstream side in a developer transport direction.   The wall surface formed between the plurality of openings is formed on a side facing the rotational direction of the upper part in the vertical direction of the conveying member. Image forming unit.   9. The image forming unit according to claim 1, wherein the height of the plurality of openings is higher than a rotational outer diameter of the conveying member.   The image forming unit according to claim 1, wherein the conveying member is synchronized in driving with the image carrier.   The image forming unit according to claim 1, wherein the conveying member has a rotatable spiral shape.   12. The image forming unit according to claim 1, wherein the conveying member is driven in synchronism with the supply member. An image carrier;
A developer carrier for supplying a developer to the image carrier;
A developer container for supplying the developer to the developer carrier;
A replenishment member for replenishing the developer to an end of the developer accommodating portion;
A conveying member that is positioned in the lower vertical direction of the replenishing member and that is long in the horizontal direction and conveys the developer in the horizontal direction;
A guide member disposed so as to cover the periphery of the transport member and guiding the developer in a horizontal direction;
The guide member has a plurality of openings from the upstream side toward the downstream side in the transport direction of the developer,
The image forming apparatus according to claim 1, wherein an opening area of the plurality of openings increases toward a downstream side in the developer conveyance direction.

Images