JP2010066578A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that includes a developing roller 36, a supply roller 38 for supplying toner to the developing roller, and a supply stabilizing member 70 for regulating an amount of toner supplied from the supply roller 38 to the developing roller 36, the developing device being configured to uniformize the contact of the supply roller 38 with the supply stabilizing member 70 in the lengthwise direction X of the supply roller 38, thereby improving image quality. <P>SOLUTION: A developing device includes hooks 81 disposed at both ends of the supply stabilizing member 70 in its lengthwise direction X. Each hook 81 engages the supply stabilizing member 70 and the shaft 46 of the supply roller 38 so as to position the supply stabilizing member 70 in the direction of the diameter of the supply roller 38. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device, and more particularly to a developing device that performs development using toner in an electrophotographic image forming apparatus such as a copying machine or a printer.

  The present invention also relates to an image forming apparatus having such a developing device.

  In image forming apparatuses such as small-sized and low-speed printers, a developing apparatus using a one-component developer in which only a toner is included in the developer is mainly used. Conventionally, as a developing device of this type, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 7-72732), a developing roller (developing device) disposed so as to be substantially in contact with a photosensitive member (electrostatic latent image carrier). Agent carrier), a sponge roller (developer supply member) that contacts the surface of the developing roller and supplies toner, and contacts the surface of the sponge roller to regulate the amount of toner supplied to the developing roller. A device including a developer regulating member is known.

In operation, the sponge roller is rotated and toner is supplied to the surface of the developing roller while being frictionally charged. Then, an electric field is applied between the developing roller and the photosensitive member, and the toner flies from the surface of the developing roller to the latent image formed on the surface of the photosensitive member. Thereby, a toner image is formed on the surface of the photoreceptor (development processing). The developer regulating member is intended to regulate the supply of a large amount of toner to the surface of the developing roller and prevent the occurrence of image defects.
JP-A-7-72732

  However, the developer regulating member exemplified in the above document is supported by the casing of the developing device and is not positioned directly with respect to the sponge roller. For this reason, with respect to the longitudinal direction of the sponge roller, the developer regulating member is attached in an inclined state with respect to the sponge roller, and the contact between the sponge roller and the developer regulating member may be uneven. . When the contact between the sponge roller and the developer regulating member becomes non-uniform as described above, the toner amount supplied to the developing roller is different in the longitudinal direction of the sponge roller, resulting in uneven density of the image. Problems arise. Further, even if the developer regulating member is pressed against the sponge roller while being pressed, the pressure becomes non-uniform in the longitudinal direction of the sponge roller, resulting in non-uniform charging of the toner, and similarly density unevenness occurs. .

  Accordingly, an object of the present invention is to provide a developing device including a developing roller, a supply roller that supplies toner to the developing roller, and a supply stabilizing member that regulates the amount of toner supplied from the supply roller to the developing roller. An object of the present invention is to provide a device capable of making the contact between the supply roller and the supply stabilizing member uniform in the longitudinal direction of the supply roller, thereby improving the image quality.

  Another object of the present invention is to provide an image forming apparatus having such a developing device.

In order to solve the above problems, the developing device of the present invention provides:
A housing containing toner;
A developing roller extending in one direction to the opening of the housing;
A supply roller that is pressed in parallel with the developing roller in the housing to form a nip portion, and rotates to supply toner to the developing roller;
A supply stabilizing member that extends along the longitudinal direction of the supply roller in the housing and contacts and regulates the amount of toner supplied from the supply roller to the developing roller;
Hooks that are disposed at both longitudinal ends of the supply stabilizing member and engage the supply stabilizing member and the shaft of the supply roller so as to position the supply stabilizing member with respect to the radial direction of the supply roller; It is provided with.

  In the developing device according to the present invention, the supply stabilizing member is disposed in the radial direction of the supply roller at both ends in the longitudinal direction of the supply stabilization member by a hook portion that engages the supply stabilization member and the shaft of the supply roller. Positioned with respect to. Therefore, the contact between the supply roller and the supply stabilizing member can be made uniform in the longitudinal direction of the supply roller, and as a result, the amount of toner supplied to the developing roller can be made uniform. Therefore, it is possible to prevent the occurrence of image density unevenness in the longitudinal direction of the supply roller. Thereby, image quality can be improved. Further, when assembling the developing device, the supply stabilizing member is easily positioned with respect to the radial direction of the supply roller by engaging the supply stabilizing member with the shaft of the supply roller via the hook portion. The Therefore, as compared with the case where the supply stabilizing member is fixed to the housing with screws, the developing device can be easily assembled.

  In the developing device according to one embodiment, the supply stabilizing member and the hooking portion are integrally formed of a continuous material.

  In the developing device of this embodiment, it is not necessary to prepare the hook portion as a member different from the supply stabilizing member. Therefore, an increase in cost due to the provision of the hook portion is suppressed.

  In the developing device according to the embodiment, the hook portion is formed in a substantially U-shaped notch that engages with the shaft of the supply roller, on a plate material disposed substantially perpendicular to the shaft of the supply roller. A groove is provided.

  In the developing device according to this embodiment, when the developing device is assembled, the supply stabilizing member is related to the radial direction of the supply roller by engaging the notch groove of the hook portion with the shaft of the supply roller. Easy positioning. Therefore, the assembly of the developing device is further facilitated.

  In the developing device according to an embodiment, the notch groove inlet is closer to the contact surface of the supply stabilizing member with respect to the supply roller than the inner peripheral portion of the notch groove. The notch groove is inclined.

  In the developing device of this embodiment, even if the supply roller rotates, the shaft of the supply roller does not exceed the entrance of the notch groove and is held on the inner peripheral portion of the notch groove. That is, it becomes difficult for the shaft of the supply roller to come off from the notch groove of the hook portion. In particular, when the supply roller has an elastic layer and the elastic layer is recessed from the natural state by pressing from the supply stabilization member, the repulsive force of the elastic layer of the supply roller to the supply stabilization member As a result, the shaft of the supply roller is biased toward the inner peripheral portion (the end portion at the back of the groove) of the notch groove. Therefore, the shaft of the supply roller is further less likely to come off from the notch groove of the hook portion. Therefore, the reliability of the developing device is improved.

  The developing device according to an embodiment includes a rotation preventing unit that prevents the supply stabilizing member from rotating around the shaft of the supply roller.

  In the developing device according to this embodiment, the rotation preventing unit prevents the supply stabilizing member from rotating around the shaft of the supply roller. Therefore, the position of the supply stabilizing member is determined with respect to the housing of the developing device, the supply roller, the developing roller, and other components. Therefore, the image quality can be further improved.

  The image forming apparatus of the present invention is an image forming apparatus having such a developing device.

  The image forming apparatus of the present invention can improve the image quality thanks to the developing device.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 shows a cross-sectional structure when a developing device 10 according to an embodiment of the present invention is cut in the vertical direction at the center with respect to the longitudinal direction (X direction). The developing device 10 generally includes a developing roller 36, a supply roller 38 for supplying toner to the developing roller 36, a supply stabilizing member 70 for stabilizing the supply of toner, the rollers 36, 38 and a housing 32 that accommodates the supply stabilizing member 70 together with the toner 90.

  As the toner 90, for example, a non-magnetic one-component toner that is negatively charged is used, and an external additive containing strontium titanate or the like is added as necessary. The diameter of the toner 90 is not particularly limited, but is, for example, 6 μm to 7 μm. Note that the present invention does not prevent the use of a positively charged toner.

  The housing 32 is formed with a toner supply opening 34 extending in a horizontal direction (X direction) perpendicular to the paper surface of FIG.

  The developing roller 36 extends in the horizontal direction (X direction) perpendicular to the paper surface of FIG. 1 so as to substantially block the opening 34 of the housing 32. The supply roller 38 has a rotation shaft (core metal) 46 parallel to a rotation shaft (not shown) of the developing roller 36, and is provided at substantially the same level along the developing roller 36 in the housing 32. The developing roller 36 and the supply roller 38 are provided so as to be rotatable around their centers O1 and O2 and in pressure contact with each other. Thus, the developing roller 36 and the supply roller 38 form a nip portion 66 as a first nip portion. The developing roller 36 and the supply roller 38 are connected to a drive source such as a motor (not shown), and rotate counterclockwise as indicated by arrows d1 and d2 in the drawing based on the drive of the drive source. . As a result, the outer peripheral surfaces of the nip portion 66 between the developing roller 36 and the supply roller 38 slide in opposite directions (counter direction). Specific configurations of the developing roller 36 and the supply roller 38 will be described later.

  The supply stabilizing member 70 is installed along the lowermost portion of the supply roller 38 in the housing 32. The supply stabilizing member 70 has a horizontal plate portion 71 extending along the longitudinal direction X of the supply roller 38 (horizontal direction perpendicular to the paper surface of FIG. 1). A specific configuration of the entire supply stabilization member 70 and how to attach it will be described later. As shown in FIG. 1, the horizontal plate portion 71 of the supply stabilizing member 70 has a top surface (first surface) in contact with the bottom of the supply roller 38 from below. Thus, the horizontal plate portion 71 of the supply stabilizing member 70 and the supply roller 38 form a nip portion 76 as a second nip portion.

  In the cross section of FIG. 1, an end 71e on the right side in FIG. 1 of the horizontal plate portion 71 of the supply stabilizing member 70 is a portion below the nip portion 66 of the developing roller 36 so as to approach the developing roller. The supply roller 38 extends to a substantially central portion of a substantially triangular region 21 (hereinafter referred to as a “first region”) sandwiched between portions below the nip portion 66 of the supply roller 38. The horizontal plate portion 71 of the supply stabilizing member 70 extends from the first region 21 to the side opposite to the first region 21 (left side in FIG. 1) with respect to the nip portion 76. In the cross section of FIG. 1, the region above the supply stabilization member 70 on the side opposite to the first region 21 with respect to the nip portion 76, more specifically, the portion of the horizontal plate portion 71 on the left side of the nip portion 76. A region between the supply roller 38 and the portion on the left side of the nip portion 76 is referred to as a “second region” 24.

  In the developing device 10, from the first region 21, the lower part of the horizontal plate portion 71 of the supply stabilizing member 70 and the left side of the left end portion 71 f in FIG. 1 of the horizontal plate portion 71 are sequentially passed to the second region 24. A reaching toner circulation channel 20 is formed. Below the horizontal plate portion 71, a horizontal flow path 22 partitioned by the lower surface of the horizontal plate portion 71 and the inner wall (horizontal plane) of the housing 32 facing the lower surface is a gap between the fixing members of the support portion 80. Is formed. Further, on the left side of the left end portion 71f of FIG. 1 of the horizontal plate portion 71, a vertical flow path partitioned by the end portion 71f and the inner wall (vertical surface) of the housing 32 facing the end portion 71f. 23 is formed. The toner circulation channel 20 allows the first region 21 to communicate with the second region 24 through the horizontal channel 22 and the vertical channel 23.

  A regulating blade 44 made of a metal plate as a regulating member is provided near the lower edge of the opening 34 in the housing 32. The regulating blade 44 is in contact with a portion below the nip portion 66 of the developing roller 36 and regulates the toner on the outer peripheral surface of the developing roller 36 supplied from the supply roller 38.

  The developing device 10 also has two conveying members 40 and 42 made of screws or the like, and the toner 90 in the housing 32 is circulated by these conveying members 40 and 42.

  In the vicinity of the upper edge of the opening 34 in the housing 32, a static elimination means 50 is provided. The neutralizing unit 50 includes a conductive member 52 that contacts the developing roller 36 and a pressing member 54 that presses the conductive member 52 against the developing roller 36.

The developing roller 36, power source 56 for applying a developing bias V _D (developing bias applying means) is connected to the developing roller 36.

The conductive member 52, a power supply 58 for applying a discharge bias V _R of the polarity and reverse polarity on the developing roller 36 to the conductive member 52 is connected.

  In the developing device 10, when the supply roller 38 rotates counterclockwise as indicated by the arrow d <b> 2, the toner 90 accommodated in the housing 32, particularly the toner present around the supply roller 38, accompanies the rotation of the supply roller 38. It is conveyed and sent from the second region 24 to the nip portion 76 between the horizontal plate portion 71 of the supply stabilizing member 70 and the supply roller 38. The amount of toner supplied from the supply roller 38 to the developing roller 36 is regulated by the nip portion 76. When the supply roller 38 further rotates, the toner regulated by the nip portion 76 is conveyed and sent to the nip portion (toner supply / collection region) 66 between the supply roller 38 and the developing roller 36. Thus, toner is supplied from the supply roller 38 to the developing roller 36 and is carried on the outer peripheral surface of the developing roller 36. At this time, the toner supplied to the developing roller 36 is precharged by friction between the developing roller 36 and the supply roller 38. As the developing roller 36 rotates counterclockwise as indicated by the arrow d 1, the toner on the outer peripheral surface of the developing roller 36 supplied from the supply roller 38 is sent to the contact portion between the developing roller 36 and the regulating blade 44. The toner on the outer peripheral surface of the developing roller 36 is regulated by the regulating blade 44 and is further charged by frictional contact with the regulating blade 44. When the developing roller 36 further rotates, the toner subjected to the regulation and charging on the outer peripheral surface of the developing roller 36 reaches a developing region 68 where the photosensitive member 4 and the developing roller 36 face each other. The toner that has reached the developing region 68 adheres to the electrostatic latent image (image forming portion) carried by the photoconductor 4 and forms a toner image on the outer peripheral surface of the photoconductor 4.

  The toner remaining on the outer peripheral surface of the developing roller 36 after being passed through the developing region 68 without being subjected to development reaches the contact portion between the developing roller 36 and the conductive member 52 as the developing roller 36 rotates. The conductive member 52 is neutralized and is easily peeled off from the developing roller 36. Thereafter, the toner that has been easily peeled off reaches the nip portion 66 between the supply roller 38 and the development roller 36 as the development roller 36 rotates, and is collected by the supply roller 38.

  When the toner is supplied from the supply roller 38 to the developing roller 36 at the nip portion 66 described above, the toner that has not adhered to the developing roller 36 tends to accumulate in the first region 21. In the developing device 10, the toner that has not adhered to the developing roller 36 at the nip portion 66 passes from the first region 21 through the toner circulation channel 20 to the second region due to the pressure of the toner that tends to accumulate in the first region 21. Pushed back to region 24. That is, the toner sequentially passes from the first region 21 through the horizontal flow path 22 below the horizontal plate portion 71 of the supply stabilizing member 70 and the vertical flow channel 23 on the left side of the left end portion 71f of the horizontal plate portion 71. And pushed back to the second region 24. The toner pushed back to the second area 24 is sent again to the nip portion 76 as the supply roller 38 rotates, and reaches the first area 21. In this way, the toner circulates through the toner circulation channel 20. Therefore, occurrence of toner packing can be prevented. As a result, image quality deterioration and gear destruction caused by toner packing are not caused. In the developing device 10, the toner is pushed back to the second region 24 by the pressure of the toner to be accumulated in the first region 21 through the toner circulation channel 20, so that it is not necessary to provide a toner stirring / conveying member or the like. . Therefore, the developing device 10 can be small and simple.

  As the developing roller 36, a general roller conventionally used in the field of the developing device can be used. For example, the developing roller 36 may be composed of a metal roller made of only a core metal such as aluminum or stainless steel as a conductive material, or acrylonitrile formed on the core metal and the outer peripheral surface of the core metal. -You may have the structure of the composite roller which consists of a coating layer which consists of butadiene rubber etc. The coating layer may be composed of a single layer or may be composed of two or more layers. In this example, the coating layer is preferably composed of two layers of an intermediate layer and a surface layer. The diameter of the developing roller 36 is desirably within a range of 10 mm to 25 mm, and is set to 16 mm in this example. The axial dimension of the developing roller 36 is set to 220 mm in this example.

  The supply roller 38 includes a cylindrical cored bar 46 and a foamed layer 48 formed on the outer periphery of the cored bar 46. As a material of the core metal 46, for example, a conductive material such as iron, stainless steel, or aluminum, a resin, or the like is used. The surface of the cored bar 46 may be plated to prevent corrosion or the like. As the material of the foam layer 48, a resin foam or a rubber foam is used. Specifically, it is desirable to use a polyurethane foam having excellent durability. Specific examples of the material used for the foam layer 48 other than polyurethane foam include foams of thermosetting resins such as epoxy resins and acrylic resins, and foams of thermoplastic resins such as polyethylene and polystyrene. The hardness of the foamed layer 48 is preferably 50N or more and 200N or less, more preferably 50N or more and 100N or less, according to the test method of JIS-K6400. The diameter of the supply roller 38 is desirably in a range of 10 mm to 20 mm in a natural state, and is set to 12 mm in this example. The axial dimension of the supply roller 38 is set to 220 mm in this example, corresponding to the axial dimension of the developing roller 36.

  The supply stabilizing member 70 can take various configurations as illustrated in FIGS. 2, 4, 8, and 10.

  In the configuration of the supply stabilization member 70 shown in FIG. 2, the supply stabilization member 70 is formed by bending a metal as a conductive material, in this example, a plate made of stainless steel (SUS301) having a thickness of 0.35 mm. Is formed. In this example, the dimension in the longitudinal direction X (X direction) of the horizontal plate portion 71 of the supply stabilizing member 70 is set to 220 mm in correspondence with the axial dimension of the developing roller 36 and the supply roller 38. In this example, the dimension in the short direction Y (Y direction) of the horizontal plate portion 71 of the supply stabilizing member 70 is set to 11 mm. In this example, enlarged portions 72 and 73 for enlarging the dimension in the lateral direction Y and vertical plate portions 81 and 82 as hook portions are provided at both ends in the longitudinal direction X of the horizontal plate portion 71 of the supply stabilizing member 70. ing. The vertical plate portions 81 and 82 extend upward in the vertical direction Z (Z direction) from both ends in the longitudinal direction X of the horizontal plate portion 71. The dimension in the vertical direction Z (Z direction) of the vertical plate portion 72 is set to 9.0 mm in this example. The dimension in the Y direction of the vertical plate portion 72 is set to 6.0 mm in this example. At substantially the center in the vertical direction Z (Z direction) of the vertical plate portions 81 and 82, substantially U-shaped notch grooves 81u and 82u that are elongated in the horizontal direction and open in the -Y direction are provided.

  When the supply stabilization member 70 is attached, as shown in FIG. 3, the supply stabilization member 70 is opposed to the + Y side with respect to the supply roller 38, and the inside of the vertical plate 81 from the inlet 81i of the notch groove 81u. The cored bar 46 of the supply roller 38 is inserted up to the peripheral portion (end portion at the back of the groove) 81e (the same applies to the cutout groove 82u of the vertical plate portion 82). Accordingly, the supply stabilization member 70 is positioned with respect to the radial direction of the supply roller 38 at both ends in the longitudinal direction X of the supply stabilization member 70 by the cutout grooves 81 u and 82 u of the vertical plate portions 81 and 82. The configuration of FIG. 3 is referred to as a structure type E1. Although not shown in detail, the supply roller 38 is pushed in by the supply stabilization member 70, and the nip portion 76 (see FIG. 1) is in a state of being recessed from the natural state by about 0.5 mm in this example.

  In this structure type E1, since the supply stabilization member 70 is positioned with respect to the radial direction of the supply roller 38, the contact between the supply roller 38 and the supply stabilization member 70 can be made uniform with respect to the longitudinal direction X of the supply roller 38. As a result, the amount of toner supplied to the developing roller 36 can be made uniform. Therefore, it is possible to prevent the density unevenness of the image from occurring in the X direction. Thereby, image quality can be improved.

  Further, the supply stabilization member 70 is easily positioned with respect to the radial direction of the supply roller 38 as compared with the case where the supply stabilization member 70 is fixed to the housing 32 with screws. Therefore, the assembly of the developing device is facilitated. Further, since the supply stabilization member 70 and the vertical plate portions 81 and 82 as the hook portions are integrally formed of a continuous material, it is necessary to prepare the hook portion as a separate member from the supply stabilization member 70. Absent. Therefore, an increase in cost due to the provision of the hook portion is suppressed.

  In the configuration of the supply stabilizing member 70 shown in FIG. 4, the supply stabilizing member 70 includes vertical plate portions 83 and 84 as hook portions instead of the vertical plate portions 81 and 82 in FIG. 2. Substantially U-shaped cutout grooves 83u and 84u are provided at substantially the center in the vertical direction Z (Z direction) of the vertical plate portions 83 and 84, respectively. The notch groove 83u is inclined with respect to the contact surface of the supply stabilizing member 70 with respect to the supply roller 38 so that the inlet 83i of the notch groove is closer to the inner peripheral portion 83e of the notch groove. (The same applies to the cutout groove 84u of the vertical plate portion 84). The other structure of the supply stabilization member 70 in FIG. 4 is the same as that in FIG.

  When the supply stabilizing member 70 is attached, as shown in FIG. 5, the supply stabilizing member 70 is opposed to the + Y side with respect to the supply roller 38, and the supply roller 38 is supported by the horizontal plate portion 71 of the supply stabilizing member 70. The lower portion of the supply roller 38 is pressed and the lower portion of the supply roller 38 is once greatly dented from the natural state, and the supply roller 38 extends from the inlet 83i of the cutout groove 83u of the vertical plate portion 83 to the inner peripheral portion (end of the groove) 83e. The core metal 46 is inserted (the same applies to the notch groove 84u of the vertical plate portion 84). Accordingly, the supply stabilizing member 70 is positioned with respect to the radial direction of the supply roller 38 at both ends in the longitudinal direction X of the supply stabilizing member 70 by the cutout grooves 83 u and 84 u of the vertical plate portions 83 and 84. The configuration of FIG. 5 is referred to as a structure type E2. Although not shown in detail, the supply roller 38 is pushed in by the supply stabilization member 70, and the nip portion 76 (see FIG. 1) is in a state of being recessed from the natural state by about 0.5 mm in this example.

  In the structure type E2, the supply stabilizing member 70 is positioned with respect to the radial direction of the supply roller 38 as in the structure type E1 of FIG. The contact with the member 70 can be made uniform, and as a result, the amount of toner supplied to the developing roller 36 can be made uniform. Therefore, it is possible to prevent the density unevenness of the image from occurring in the X direction. Thereby, image quality can be improved.

  Further, the supply stabilization member 70 is easily positioned with respect to the radial direction of the supply roller 38 as compared with the case where the supply stabilization member 70 is fixed to the housing 32 with screws. Therefore, the assembly of the developing device is facilitated.

  Moreover, in this structure type E2, the cored bar 46 of the supply roller 38 is notched by the repulsive force of the supply roller 38 against the supply stabilizing member 70 of the elastic layer. ) 83e. Therefore, the cored bar 46 of the supply roller 38 is unlikely to come off from the cutout grooves 83u and 84u of the vertical plate portions 83 and 84. Therefore, the reliability of the developing device 10 is improved.

  6 and 7 show a structure type obtained by modifying the structure type E2 of FIG. 5 (this is referred to as E3) (FIG. 7 omits the developing roller 36 in the vicinity of the supply roller 38 in FIG. 6). And shows a view from the + Y direction.) In this structure type E3, 3 mm square projections 91 and 92 as rotation preventing portions are provided in a portion 32b of the housing 32 corresponding to the portion immediately below the enlarged portions 72 and 73 of the supply stabilizing member 70. The protrusions 91 and 92 are made of resin in this example, but may be made of metal. Further, the protrusions 91 and 92 may be attached to the housing 32 or may be formed integrally with the housing 32 with the same material as that of the housing 32.

  This structure type E3 has the same effects as the structure type E2 of FIG. Moreover, the protrusions 91 and 92 prevent the supply stabilizing member 70 from rotating around the core metal 46 of the supply roller 38. Therefore, the position of the supply stabilization member 70 is determined with respect to the housing 32, the supply roller 38, the development roller 36, and other components of the developing device 10. Therefore, the image quality can be further improved.

  In the configuration of the supply stabilization member 70 shown in FIG. 8, the supply stabilization member 70 includes vertical plate portions 85 and 86 as hook portions instead of the vertical plate portions 83 and 84 in FIG. At substantially the center in the vertical direction Z (Z direction) of the vertical plate portions 85 and 86, substantially U-shaped cutout grooves 81u and 82u opened in the + Y direction are provided, respectively. The enlarged portions 72 and 73 of the supply stabilizing member 70 are omitted, and instead, the −Y side ends 85s and 86s of the vertical plate portions 85 and 86 are the −Y side of the horizontal plate portion 71 of the supply stabilizing member 70. It protrudes in the −Y direction from the end portion 71f of the.

  When the supply stabilizing member 70 is attached, as shown in FIG. 9, the supply stabilizing member 70 is opposed to the −Y side with respect to the supply roller 38, and the supply roller is moved by the horizontal plate portion 71 of the supply stabilizing member 70. 38, the lower portion of the supply roller 38 is pressed and the lower portion of the supply roller 38 is once greatly recessed from the natural state, and the supply roller extends from the inlet 85i of the cutout groove 85u of the vertical plate portion 85 to the inner peripheral portion (end of the groove) 85e. 38 cored bars 46 are inserted (the same applies to the notch groove 86u of the vertical plate portion 86). Accordingly, the supply stabilizing member 70 is positioned with respect to the radial direction of the supply roller 38 at both ends in the longitudinal direction X of the supply stabilizing member 70 by the cutout grooves 85 u and 86 u of the vertical plate portions 85 and 86. The configuration of FIG. 9 is referred to as a structure type E4. Although not shown in detail, the supply roller 38 is pushed in by the supply stabilization member 70, and the nip portion 76 (see FIG. 1) is in a state of being recessed from the natural state by about 0.5 mm in this example.

  This structure type E4 has the same effects as the structure type E2 of FIG. In addition, the −Y side end portions 85 s and 86 s of the vertical plate portions 85 and 86 are in contact with the opposing portion 32 s of the housing 32, thereby functioning as a rotation preventing portion. That is, the supply stabilizing member 70 rotates around the cored bar 46 of the supply roller 38 by the −Y side end portions 85 s and 86 s of the vertical plate portions 85 and 86 coming into contact with the opposing portion 32 s of the housing 32. Is prevented. Therefore, the position of the supply stabilization member 70 is determined with respect to the housing 32, the supply roller 38, the development roller 36, and other components of the developing device 10. Therefore, the image quality can be further improved.

  FIG. 10 shows a structure type (referred to as E5) obtained by modifying the structure type E4 of FIG. In this example, contrary to the previous examples, the developing roller 36 and the supply roller 38 rotate in the directions of arrows d3 and d4 in the clockwise direction around their centers O1 and O2. As a result, at the nip portion between the developing roller 36 and the supply roller 38, the outer peripheral surfaces slide in opposite directions (counter directions). Accordingly, a regulating blade 44 ′ that regulates toner on the outer peripheral surface of the developing roller 36 is provided in the vicinity of the upper edge of the opening 34 in the housing 32. Further, a static eliminating means 50 ′ is provided in the housing 32 in the vicinity of the lower edge of the opening 34.

  In this structure type E5, the supply stabilizing member 70 is disposed so as to contact the upper portion of the supply roller 38. At both ends in the longitudinal direction X of the supply stabilizing member 70, vertical plate portions 87 are provided as hook portions. The vertical plate 87 is provided with a substantially U-shaped cutout groove 87u that opens in the -Y direction. The notch groove 87u is inclined with respect to the contact surface of the supply stabilizing member 70 with respect to the supply roller 38 such that the inner peripheral portion 87e of the notch groove is closer to the inlet 87i of the notch groove. Yes. This structure type E5 has the same effects as the structure type E2 of FIG.

  Further, in this structure type E5, the −Z side end portion 87b of the vertical plate portion 87 is in contact with the opposing portion 32b of the housing 32, and functions as a rotation preventing portion. That is, the supply stabilizing member 70 is prevented from rotating around the core metal 46 of the supply roller 38 by the end portion 87s on the −Z side of the vertical plate portion 87 coming into contact with the opposing portion 32s of the housing 32. The Therefore, the position of the supply stabilization member 70 is determined with respect to the housing 32, the supply roller 38, the development roller 36, and other components of the developing device 10. Therefore, the image quality can be further improved.

  The inventor has developed a developing device used in a Konica Minolta color laser printer (trade name: magiccolor 5570) with various structural types E1, E2 as shown in FIG. 3, FIG. 5, FIG. 6, FIG. , E3, E4, and E5 were modified and the verification experiment of the present invention was performed. The table of FIG. 12 is a comparative example (Examples 1, 2, 3, 4, 5 having the structure types E1, E2, E3, E4, and E5 described above, and a supply stabilizing member 970 shown in FIG. 11). This is the structure type C1), and the evaluation results when performing the verification experiment are shown.

  In the structural type C1 of the comparative example, the supply stabilization member 970 includes a horizontal plate portion 971 extending along the longitudinal direction X of the supply roller 938, and an upper side from the side edge on the −Y side of the horizontal plate portion 971 (Z Vertical plate portion 972 extending in the direction), and L-shaped support portions 974 and 975 provided at both ends of the horizontal plate portion 971 in the longitudinal direction X. The supply stabilization member 970 is fixed to the housing 32 via support portions 974 and 975. The dimension of the horizontal plate portion 971 of the supply stabilization member 970 is set to be the same as the dimension of the horizontal plate portion 71 of the supply stabilization member 70 described above.

  In the verification experiment, for each of Examples 1, 2, 3, 4, 5 and the comparative example, a predetermined paper (Japanese Industrial Standard A4 paper) is conveyed in the vertical direction, and cyan toner is used for the paper. Half images were output, and the presence or absence of density unevenness was evaluated in three stages (symbols ◎, ○, ×). The symbol “◎” indicates that no density unevenness is observed, the symbol “◯” indicates that density unevenness has occurred but is within the allowable range, and the symbol “x” indicates that density unevenness exceeding the allowable range has occurred. As is apparent from the table of FIG. 12, in the comparative example, x (concentration unevenness exceeding the allowable range was generated), but in the examples having the above-described structure types E1, E2, E3, E4, and E5, respectively. In 1, 2, 3, 4, and 5, all were ◎ (concentration unevenness was not observed). Thus, in Examples 1, 2, 3, 4, and 5 having the above-described structure types E1, E2, E3, E4, and E5, preferable results were obtained.

  As described above, if the supply stabilization member 70 is made of a conductive material, the potential of the supply stabilization member 70 can be controlled. That is, the toner supply from the supply roller 38 to the developing roller 36 can be stabilized by preliminarily charging the toner by controlling the potential of the supply stabilization member 70 to be equal to the potential of the supply roller 38, for example. In addition, the connection of the power supply to the supply stabilization member 70 can be performed with respect to the longitudinal direction edge part of the horizontal board part 71, for example.

  Further, by configuring the supply stabilization member 70 with relatively thin stainless steel as described above, at least the horizontal plate portion 71 of the supply stabilization member 70 exhibits flexibility. Therefore, the contact pressure between the horizontal plate portion 71 of the supply stabilizing member 70 and the supply roller 38 can be easily adjusted. For example, when the supply roller 38 rotates around the center O2, the horizontal plate portion 71 of the supply stabilization member 70, the supply roller 38, and the like are caused by the outer diameter fluctuation and eccentricity of the supply roller 38 and the vibration of the shaft of the supply roller 38. Variation factors may occur in the manner of contact between the two. Even if such a variation factor occurs, the horizontal plate portion 71 of the supply stabilization member 70 bends so as to absorb the variation. Therefore, the manner of contact between the horizontal plate portion 71 of the supply stabilizing member 70 and the supply roller 38 is stabilized. As a result, the supply of toner from the supply roller 38 to the developing roller 36 can be stabilized.

  In the above-described embodiment, the plate-shaped regulating blade is provided as the regulating member. However, the present invention is not limited to this, and the regulating member may be a roller.

  FIG. 13 shows a schematic configuration of an image forming apparatus to which the developing device of the present invention is applied. However, in order to facilitate understanding, the housing of the image forming apparatus is omitted from the drawing.

  The image forming apparatus 102 is an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a combination of these functions. At present, various types of electrophotographic image forming apparatuses have been proposed, but the illustrated image forming apparatus is a monochrome image forming apparatus having only one developing device. However, the present invention is not only applied to this type of image forming apparatus, but is equally applicable to other types of image forming apparatuses, for example, so-called tandem type or four-cycle type color image forming apparatuses.

  The image forming apparatus 102 includes a cylindrical photosensitive member 4 as an electrostatic latent image carrier. Around the photoreceptor, a charging device 106, an exposure device 108, a developing device 10, a transfer roller 112 as a transfer device, and a cleaning member 114 are arranged in this order along the rotation direction (clockwise in the figure). Yes. A contact portion (nip portion) between the photoreceptor 4 and the transfer roller 112 forms a transfer region 68.

  In the embodiment, a plate-like blade is used as the cleaning member 114, and one end side thereof is in contact with the outer peripheral surface of the photoreceptor 4. However, the cleaning member 114 is not limited to a blade, and other cleaning members (for example, a fixed brush, a rotating brush, and a roller) can be used.

  The conveyance path 126 extends from a paper feeding device (not shown) through a nip part 120 of the paper feeding roller pair 116, a transfer region 122, and a nip part 124 of the fixing roller pair 118 to a paper discharging part (not shown).

  An example of the image forming operation will be briefly described. First, the outer peripheral surface of the photoreceptor 4 that is rotationally driven at a predetermined peripheral speed is charged by the charging device 106. Next, light corresponding to the image information is projected from the exposure device 108 onto the outer peripheral surface of the charged photoconductor 4 to form an electrostatic latent image. Subsequently, the electrostatic latent image is made visible by the developer toner supplied from the developing device 10. The toner image formed on the photoreceptor 4 in this way reaches the transfer region 122 by the rotation of the photoreceptor 4.

  On the other hand, in accordance with the timing, the sheet (recording medium) accommodated in the sheet feeding device is sent to the conveying path 126 by the rotation of the sheet feeding roller 116 and is conveyed to the transfer region 122. In the transfer area 122, the toner image on the photoconductor 4 is transferred to a sheet. The sheet on which the toner image has been transferred is conveyed further downstream in the conveyance path 126, and after the toner image is fixed on the sheet by the fixing roller 118, it is sent out to the paper discharge unit.

  The toner remaining on the photosensitive member 4 without being transferred to the paper is scraped off by the cleaning member 114 and removed from the outer peripheral surface of the photosensitive member 4 when reaching the contact portion between the photosensitive member 4 and the cleaning member 114. Is done.

It is a figure which shows the cross-section when the developing device of one Embodiment of this invention is cut | disconnected in the perpendicular direction. It is a figure which shows a certain supply stabilization member of the said developing device. It is a figure which shows the structure type provided with the supply stabilization member of FIG. 2 of the said developing device. It is a figure which shows another supply stabilization member of the said developing device. It is a figure which shows the structural type provided with the supply stabilization member of FIG. 4 of the said developing device. It is a figure which shows another structure type of the said developing device. FIG. 7 is a diagram showing the vicinity of the supply roller in FIG. 6 as viewed from the + Y direction with the developing roller omitted. It is a figure which shows another supply stabilization member of the said developing device. It is a figure which shows the structure type of the said developing device provided with the supply stabilization member of FIG. It is a figure which shows another structure type of the said developing device. It is a figure which shows the supply stabilization member used for a comparative example. It is a figure which shows the result of the verification experiment about an Example and a comparative example. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Developing apparatus 20 Toner circulation flow path 32 Housing 36 Developing roller 38 Supply roller 70 Supply stabilization member 71 Horizontal plate part 81,82,83,84,85,86,87 Vertical plate part

Claims (6)

A housing containing toner;
A developing roller extending in one direction to the opening of the housing;
A supply roller that is pressed in parallel with the developing roller in the housing to form a nip portion and rotates to supply toner to the developing roller;
A supply stabilizing member that extends along the longitudinal direction of the supply roller in the housing and contacts and regulates the amount of toner supplied from the supply roller to the developing roller;
Hooks that are disposed at both longitudinal ends of the supply stabilization member and engage the supply stabilization member and the shaft of the supply roller so as to position the supply stabilization member with respect to the radial direction of the supply roller; A developing device comprising: The developing device according to claim 1,
The developing device, wherein the supply stabilizing member and the hooking portion are integrally formed of a continuous material. The developing device according to claim 1 or 2,
The hook portion is formed by providing a substantially U-shaped notch groove that engages with the shaft of the supply roller in a plate material disposed substantially perpendicular to the shaft of the supply roller. A developing device. The developing device according to claim 3,
The notch groove is inclined so that the inlet of the notch groove is closer to the contact surface of the supply stabilizing member with respect to the supply roller than the inner peripheral portion of the notch groove. A developing device. In the developing device according to any one of claims 1 to 4,
A developing device, comprising: a rotation preventing portion that prevents the supply stabilizing member from rotating about the shaft of the supply roller.   An image forming apparatus comprising the developing device according to claim 1.

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