JP2009300512A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device for preventing image irregularities, especially image irregularities along the longitudinal direction of a feed roller, and improving the image quality. <P>SOLUTION: A developing device includes a housing 32, a developing roller 34 which horizontally extends in an opening 34 of the housing, and the feed roller 38 which is set in the housing 32 in parallel with the developing roller 34 so as to form a nip portion 66 and which feeds toner to the developing roller 36. The developing device also includes a feed stabilizing member 70 which is in contact with a lower portion of the feed roller 38 so as to form a second nip portion 76, and which restricts toner feed quantity. Of the feed stabilizing member 70, a part 71 forming the second nip portion 76 is formed in a flexible plate shape extending in the X direction. Of the lower surface of the plate-like part 71 of the feed stabilizing member 70, the inside other than both ends related to at least the X direction is provided with a support section 80 for supporting the plate-like part 71 against the pressure from the feed roller 38. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In general, in an electrophotographic image forming apparatus, a photosensitive member is exposed to form an electrostatic latent image on the surface of the photosensitive member, and the electrostatic latent image is developed by a developing device. Then, a toner image is formed, and the toner image is transferred and fixed on a sheet as a recording medium.

  As this type of developing device, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2006-98854) and Patent Document 2 (Japanese Patent Laid-Open No. 2006-98855) describe a developing roller that conveys toner to a case, a photoreceptor, and a developing roller. A supply roller that is pressed against the toner and supplies a toner, a regulating blade that regulates the toner, a toner agitation conveyance member that agitates and conveys the toner, and a toner that is conveyed by the toner agitation conveyance member, and guides it toward the supply roller And a toner receiving member is described. The developing roller is disposed in the opening of the case so as to be substantially in contact with the photosensitive member, while the supply roller, the regulating blade, the toner stirring and conveying member, and the toner receiving member are all disposed in the case. The developing roller and the supply roller rotate in the same direction around the respective central axes. As a result, the outer peripheral surfaces of the nip portion between the developing roller and the supply roller are opposite to each other (counter direction). To slide. The regulating blade is in contact with a portion below the nip portion of the developing roller within the case and regulates the toner on the developing roller supplied from the supply roller.

  In Patent Document 3 (Japanese Patent Laid-Open No. 2007-3889), Patent Document 4 (Japanese Patent Laid-Open No. 2002-24437), and Patent Document 5 (Japanese Patent Laid-Open No. 2003-107903), the toner receiving member is provided below the supply roller. A developing device having substantially the same configuration is disclosed in which members corresponding to the above (referred to as a stay member, a horizontal member, and a holding member, respectively, hereinafter referred to as “supply stabilizing member”) are disposed.

Conventionally, the supply stabilizing member as described above is generally configured as a supply stabilizing member 970 shown in FIG. 10, for example. The supply stabilizing member 970 includes a horizontal plate portion 971 extending along the longitudinal direction X of the supply roller 938, and a Y direction of the horizontal plate portion 971 (perpendicular to the X direction within the plane along the horizontal plate portion 971). A vertical plate portion 972 extending upward (Z direction) from one side edge with respect to a longitudinal direction), and L-shaped support portions 974 and 975 provided at both ends of the horizontal plate portion 971 with respect to the longitudinal direction X. . The supply stabilization member 970 is fixed to the case via support portions 974 and 975.
JP 2006-98854 A JP 2006-98855 A JP 2007-3889 A JP 2002-24437 A JP 2003-107903 A

  By the way, when the supply roller 938 rotates around the central axis O2, the outer diameter fluctuation and eccentricity of the supply roller 938 and the vibration of the shaft of the supply roller 938 cause a gap between the supply roller 938 and the supply stabilization member 970. Variation factors may occur in the manner of contact.

  However, in the configuration like the supply stabilization member 970 shown in FIG. 10, the supply stabilization member 970 is fixed to the case only at both ends with respect to the longitudinal direction X via the support portions 974 and 975. Inside the member 970 in the longitudinal direction X, the contact force of the supply stabilizing member 970 with respect to the supply roller 938 becomes weak. For this reason, there is a problem that image unevenness occurs particularly in the longitudinal direction X and the image quality is impaired.

  Accordingly, an object of the present invention is to provide a developing device that can suppress image unevenness, particularly image unevenness along the longitudinal direction of a supply roller, thereby improving image quality.

In order to solve the above problems, the developing device of the present invention provides:
A housing;
A developing roller extending horizontally in the opening of the housing;
A supply roller that is pressed in parallel with the developing roller in the housing to form a first nip portion, and rotates to supply toner to the developing roller;
Supplying toner from the supply roller to the developing roller, which is installed in the housing, forms a second nip portion in contact with a portion of the supply roller that is upstream of the first nip portion in the rotational direction. A supply stabilizing member for regulating the amount,
The portion of the supply stabilizing member that forms the second nip portion is formed in a plate shape that extends in the longitudinal direction along the axial direction of the supply roller and exhibits flexibility,
Of the second surface opposite to the first surface forming the second nip portion of the plate-like portion of the supply stabilizing member, the supply is provided at least inside the end portion other than both ends with respect to the longitudinal direction. A support portion for supporting the plate-like portion against the pressure from the roller is provided.

  In the developing device of the present invention, the supply roller is pressed in parallel with the developing roller to form the first nip portion and rotates. Then, the toner present in the housing, particularly around the supply roller, is conveyed along with the rotation of the supply roller, and is fed into the second nip portion. The second nip portion regulates the amount of toner supplied from the supply roller to the developing roller. When the supply roller further rotates, the toner regulated by the second nip portion is conveyed and sent to the first nip portion between the supply roller and the developing roller. Thus, the toner is supplied from the supply roller to the developing roller and is carried on the outer peripheral surface of the developing roller. The toner on the outer peripheral surface of the developing roller is regulated by, for example, a known regulating member as the developing roller rotates, and then develops the electrostatic latent image on the surface of the photoconductor that is the development target of the developing device. Used to do.

  When the supply roller rotates, the supply roller outer diameter fluctuation and eccentricity, and the vibration of the supply roller shaft may cause variations in the manner of contact between the supply roller and the supply stabilization member. Here, in this developing device, a portion of the supply stabilizing member that forms the second nip portion extends in a longitudinal direction along the axial direction of the supply roller and has a plate shape that exhibits flexibility. Is formed. Therefore, the supply stabilizing member bends to absorb the variation. Therefore, the manner of contact between the supply roller and the supply stabilization member is stabilized. Moreover, at least inside the second surface opposite to the first surface forming the second nip portion of the plate-like portion of the supply stabilizing member, except at both ends with respect to the longitudinal direction, A support portion that supports the plate-like portion against the pressure from the supply roller is provided. Therefore, the abutment force of the supply stabilizing member with respect to the supply roller is ensured internally in the longitudinal direction by the support portion. Therefore, image unevenness, particularly image unevenness along the longitudinal direction of the supply roller can be suppressed. Thereby, the image quality can be improved.

  The support part is preferably supported by, for example, an inner wall of the housing or a component formed integrally with the inner wall.

  It is desirable to provide a regulating member that regulates toner on the developing roller in contact with a portion of the developing roller that is downstream of the first nip portion in the rotation direction in the housing. Further, it is desirable that the restricting member extends along the axial direction of the developing roller.

In another aspect, the developing device of the present invention comprises:
A housing containing non-magnetic single component toner;
A developing roller extending horizontally in the opening of the housing;
A supply roller that is pressed in parallel with the developing roller in the housing to form a first nip portion, rotates in the same direction as the developing roller, and supplies toner to the developing roller;
A toner is installed in the housing and forms a second nip portion in contact with a lower portion of the supply roller on the upstream side in the rotation direction than the first nip portion, and the toner from the supply roller to the developing roller A supply stabilizing member that regulates the supply amount of the developing roller, and the supply stabilizing member includes a portion below the first nip portion of the developing roller and a first nip portion of the supply roller. Extends from the substantially triangular first region sandwiched between the lower portion to the opposite side of the first region with respect to the second nip portion,
The supply stabilization on the side opposite to the first region with respect to the second nip portion from the first region and below the supply stabilization member due to the pressure of the toner to be accumulated in the first region. A toner circulation channel that pushes the toner back to a second region corresponding to the upper part of the member;
The portion of the supply stabilizing member that forms the second nip portion is formed in a plate shape that extends in the longitudinal direction along the axial direction of the supply roller and exhibits flexibility,
Of the second surface opposite to the first surface forming the second nip portion of the plate-like portion of the supply stabilizing member, the supply is provided at least inside the end portion other than both ends with respect to the longitudinal direction. A support portion for supporting the plate-like portion against the pressure from the roller is provided.

  Here, “lower” and “upper” are determined according to the direction of gravity.

  In the developing device of the present invention, the supply roller is pressed in parallel with the developing roller to form the first nip portion, and rotates in the same direction as the rotation direction of the developing roller. Then, the toner accommodated in the housing, particularly the toner present around the supply roller, is conveyed along with the rotation of the supply roller, and is fed from the second region to the second nip portion. The second nip portion regulates the amount of toner supplied from the supply roller to the developing roller. When the supply roller further rotates, the toner regulated by the second nip portion is conveyed and sent to the first nip portion between the supply roller and the developing roller. Thus, the toner is supplied from the supply roller to the developing roller and is carried on the outer peripheral surface of the developing roller. The toner on the outer peripheral surface of the developing roller is regulated by, for example, a known regulating member as the developing roller rotates, and then develops the electrostatic latent image on the surface of the photoconductor that is the development target of the developing device. Used to do.

  When the supply roller supplies toner to the developing roller, the toner that has not adhered to the developing roller at the first nip portion tends to accumulate in the first region. Here, in this developing device, the toner that has not adhered to the developing roller at the first nip portion passes from the first region through the toner circulation channel due to the pressure of the toner that tends to accumulate in the first region. Then, it passes back below the supply stabilizing member and is pushed back to the second region corresponding to the upper side of the supply stabilizing member on the side opposite to the first region. The toner pushed back to the second region is sent again to the second nip portion as the supply roller rotates, and reaches the first region. In this way, the toner circulates through the toner circulation channel. Therefore, occurrence of toner packing can be prevented. As a result, image quality deterioration and gear destruction caused by toner packing are not caused. Further, in this developing device, the toner is pushed back to the second region by the pressure of the toner that is to be accumulated in the first region through the toner circulation flow path, so that it is disclosed in each of the aforementioned patent documents. It is not necessary to provide a toner agitating and conveying member. Therefore, the developing device of the present invention can be configured in a small and simple manner.

  When the supply roller rotates, the supply roller outer diameter fluctuation and eccentricity, and the vibration of the supply roller shaft may cause variations in the manner of contact between the supply roller and the supply stabilization member. Here, in this developing device, a portion of the supply stabilizing member that forms the second nip portion extends in a longitudinal direction along the axial direction of the supply roller and has a plate shape that exhibits flexibility. Is formed. Therefore, the supply stabilizing member bends to absorb the variation. Therefore, the manner of contact between the supply roller and the supply stabilization member is stabilized. Moreover, at least inside the second surface opposite to the first surface forming the second nip portion of the plate-like portion of the supply stabilizing member, except at both ends with respect to the longitudinal direction, A support portion that supports the plate-like portion against the pressure from the supply roller is provided. Therefore, the abutment force of the supply stabilizing member with respect to the supply roller is ensured internally in the longitudinal direction by the support portion. Therefore, image unevenness, particularly image unevenness along the longitudinal direction of the supply roller can be suppressed. Thereby, the image quality can be improved.

  For example, the support portion is configured to resist pressure from the plate-like portion of the supply stabilization member (mainly pressure from the supply roller) by, for example, an inner wall of the housing or a component formed integrally with the inner wall. It is desirable to be supported.

  It is preferable that a regulating member for regulating toner on the developing roller is provided in contact with a lower portion of the developing roller in the rotation direction downstream of the first nip portion in the housing. Further, it is desirable that the restricting member extends along the axial direction of the developing roller.

  In the developing device according to an embodiment, a plurality of the support portions are provided apart from each other inside the second surface of the supply stabilizing member other than both end portions with respect to the longitudinal direction. And

  In the developing device of this embodiment, the contact force of the supply stabilizing member with respect to the supply roller is ensured by the plurality of support portions so as to be substantially uniform inside in the longitudinal direction. Therefore, image unevenness, particularly image unevenness along the longitudinal direction of the supply roller can be further suppressed. Thereby, the image quality can be further improved. Since the support portions are separated from each other in the longitudinal direction, the toner that has not adhered to the developing roller at the first nip portion is located below the supply stabilizing member between the support portions. Can flow through the gap.

  In the developing device according to one embodiment, the support portion is configured such that the dimension in the longitudinal direction is smaller than the dimension in the other direction.

  In the developing device according to this embodiment, the toner that has not adhered to the developing roller at the first nip portion flows better under the supply stabilizing member through the gap between the support portions. be able to.

  In the developing device according to the embodiment, the support portion corresponds to a part of the plate-like portion in the short direction perpendicular to the longitudinal direction in the plane along the plate-like portion of the supply stabilizing member. It arrange | positions to the area | region which carries out.

  In the developing device according to this embodiment, the support portion is only arranged in a region corresponding to a part of the plate-like portion in the short direction. Therefore, when the toner that has not adhered to the developing roller at the first nip portion passes below the supply stabilizing member, the section in which the flow is prevented by the support portion is short. Therefore, the toner can flow better under the supply stabilizing member. In addition, the supply stabilizing member exhibiting flexibility is easily bent, and the manner of contact between the supply roller and the supply stabilizing member is further stabilized.

  In the developing device according to an embodiment, the region where the support portion is disposed with respect to the short direction is a section farther from the developing roller than the second nip portion, and the second nip portion. A section closer to the developing roller than the portion is a space.

  In the developing device of this embodiment, the section closer to the developing roller than the second nip portion is a space in the short direction. Therefore, the toner that has not adhered to the developing roller at the first nip portion can easily enter the lower portion of the supply stabilizing member. Subsequently, the toner that has entered the lower portion of the supply stabilizing member flows through a gap between the support portions disposed in a section farther from the developing roller than the second nip portion. Therefore, the toner can flow better under the supply stabilizing member.

  In the developing device according to an embodiment, a plate-like connecting portion that integrally connects the plurality of support portions is provided in parallel with the plate-like portion of the supply stabilizing member.

  In the developing device of this embodiment, a plate-like connecting portion that integrally connects the plurality of support portions is provided in parallel to the plate-like portion of the supply stabilizing member. Therefore, first, the plurality of support portions are formed in a state of being connected by the connection portion, and then, if the plurality of support portions are attached to the plate-like portion of the supply stabilizing member, the assembly can be easily performed. it can. And the clearance gap between the said support parts can be set easily and accurately.

  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. 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 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 have rotation shafts (not shown) parallel to each other, and 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 includes a horizontal plate portion 71 extending in the longitudinal direction X of the supply roller 38 (horizontal direction perpendicular to the paper surface of FIG. 1), and the longitudinal direction X in the plane along the horizontal plate portion 71. A vertical plate portion 72 extending upward (Z direction) from a side edge on one side (left side in FIG. 1) with respect to the transverse direction Y perpendicular to the vertical direction. The supply stabilization member 70 is fixed to the housing 32 via a support portion 80 provided on the lower surface (second surface) of the horizontal plate portion 71. 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. Although not shown in detail, in the nip portion 76, the supply roller 38 is pushed in by the supply stabilizing member 70, and is in a state of being depressed about 0.5 mm in this example from the natural state. The support portion 80 is, for example, as shown in FIG. 2 (as viewed from obliquely below), as shown in FIG. 2 (in this example, five fixing members 81A, 81B,..., 81E separated from each other). In the lower surface of the supply stabilization member 70, a plurality of them are provided apart from each other inside the both ends in the longitudinal direction X. In this example, the support portion 80 is preferably supported by the inner wall of the housing 32, and supports the horizontal plate portion 71 against the pressure from the supply roller 38. Specific configurations of the supply stabilizing member 70 and the support portion 80 will be described later.

  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 and continues to the vertical plate portion 72. . The upper end 72 f of the vertical plate portion 72 is located above the nip portion 66. In the cross section of FIG. 1, on the side opposite to the first region 21 with respect to the nip portion 76, the region above the supply stabilizing member 70, more specifically, the horizontal plate portion 71, the vertical plate portion 72, and the supply roller 38. The generally enclosed area is referred to as a “second area” 24.

  In the developing device 10, the toner circulation flow path 20 reaches the second region 24 sequentially from the first region 21 through the lower side of the horizontal plate portion 71 of the supply stabilizing member 70 and the left side of the vertical plate portion 72 in FIG. 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 vertical plate portion 72, a vertical flow path 23 partitioned by the left side surface of the vertical plate portion 72 in FIG. 1 and the inner wall (vertical surface) of the housing 32 facing the left side surface is formed. ing. 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 vertical plate portion 72 to the second region 24. Pushed back. 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. Further, in the developing device 10, the toner is pushed back to the second region 24 by the pressure of the toner that tries to accumulate in the first region 21 through the toner circulation channel 20, so that it is disclosed in Patent Documents 1 to 4. It is not necessary to provide a toner agitating and conveying member. Therefore, the developing device 10 can be configured in a smaller and simpler manner than the developing devices disclosed in Patent Documents 1 to 4.

  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 is formed by bending a metal as a conductive material, in this example, a plate made of stainless steel (SUS301) having a thickness of 0.2 mm as shown in FIG. 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. The vertical dimension Z (Z direction) of the vertical plate portion 72 of the supply stabilizing member 70 is set to 2.5 mm in this example.

  Thus, 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 addition, a support portion 80 that supports the horizontal plate portion 71 against the pressure from the supply roller 38 is provided at least inside the lower surface of the horizontal plate portion 71 of the supply stabilizing member 70 except for both end portions in the longitudinal direction X. Is provided. Therefore, the abutment force of the supply stabilizing member 70 with respect to the supply roller 38 is ensured inside the longitudinal direction X by the support portion 80. Therefore, image unevenness, particularly image unevenness along the longitudinal direction X can be suppressed. Thereby, the image quality can be improved.

  The present inventor provides the above-described supply stabilizing member 70 to the developing unit used in the Konica Minolta color laser printer (trade name: magiccolor 5570), and a support portion 80 for supporting the supply stabilizing member 70. Is modified to support portions 80-1, 80-2, 80-3, 80-4 having various structure types E1, E2, E3, E4 as shown in FIGS. Thus, a verification experiment of the present invention was conducted. 2, 3, 4, and 5 (and FIG. 9 described later) are views from the same viewpoint, and the XYZ coordinates shown in FIG. 2 are used in common.

  Note that the Z-direction dimension of the horizontal flow path 22 and the Y-direction dimension of the vertical flow path 23 constituting the toner circulation flow path 20 shown in FIG. 1 are both set to 3 mm in this example.

  The support portion 80-1 of the structure type E1 shown in FIG. 2 includes five fixing members 81A, 81B, 81C, 81D, and 81E that are separated from each other in the X direction. Each of the fixing members 81A, 81B,..., 81E is made of a resin material and is formed in an elongated prismatic shape along the Y direction. The dimension in the X direction of each fixing member 81A, 81B,..., 81E is set to 4 mm. The dimension in the Y direction of each of the fixing members 81A, 81B,..., 81E is set to 11 mm corresponding to the dimension in the Y direction of the horizontal plate portion 71. Moreover, the Z direction dimension of each fixing member 81A, 81B, ..., 81E is set to 3 mm corresponding to the Z direction dimension of the horizontal flow path 22.

  In this structure type E1, both ends of the fixing members 81A, 81B,..., 81E in the Y direction coincide with both ends of the horizontal plate portion 71 in the Y direction.

  The support portion 80-2 of the structure type E2 shown in FIG. 3 includes five fixing members 82A, 82B, 82C, 82D, and 82E that are separated from each other in the X direction. Each of the fixing members 82A, 82B,..., 82E corresponds to the fixing member 81A, 81B,. The dimension in the X direction of each of the fixing members 82A, 82B,..., 82E is set to 4 mm, similar to the dimension in the X direction of the fixing members 81A, 81B,. The dimension in the Y direction of each fixing member 82A, 82B,..., 82E is set to 5.5 mm corresponding to 1/2 of the dimension in the Y direction of the horizontal plate portion 71. Moreover, the Z direction dimension of each fixing member 82A, 82B,..., 82E corresponds to the Z direction dimension of the horizontal flow path 22 similarly to the Z direction dimension of the fixing members 81A, 81B,. It is set to 3 mm.

  In this structure type E2, one end in the Y direction of each fixing member 82A, 82B,..., 82E (the end on the back side in FIG. 3) is one end in the Y direction of the horizontal plate portion 71 (the back side in FIG. 3). Edge). The other end of each fixing member 82A, 82B,..., 82E in the Y direction (the end on the near side in FIG. 3) is located in the center with respect to the Y direction of the horizontal plate portion 71.

  The support portion 80-3 of the structure type E3 shown in FIG. 4 includes five fixing members 83A, 83B, 83C, 83D, and 83E that are separated from each other in the X direction. Each of the fixing members 83A, 83B,..., 83E is formed by bending a plate material made of stainless steel (SUS301) having a thickness of 0.2 mm into a U-shape. Specifically, like the fixing member 84 shown in FIG. 6, each of the fixing members 83A, 83B,..., 83E includes a horizontal plate portion 841 to be attached to the lower surface of the horizontal plate portion 71 of the supply stabilizing member 70. The horizontal plate portion 842 is parallel to the horizontal plate portion 841 and should be attached to the inner wall of the housing 32, and the vertical plate portion 843 connecting the horizontal plate portions 841 and 842. The dimension in the X direction of each of the fixing members 83A, 83B, ..., 83E shown in Fig. 4 is set to 10 mm in this example. The dimension in the Y direction of each of the fixing members 83A, 83B,..., 83E is set to 11 mm corresponding to the dimension in the Y direction of the horizontal plate portion 71. Moreover, the Z direction dimension of each fixing member 83A, 83B,..., 83E is set to 3 mm corresponding to the Z direction dimension of the horizontal flow path 22.

  In this structure type E1, both ends of the fixing members 83A, 83B,..., 83E in the Y direction coincide with both ends of the horizontal plate 71 in the Y direction.

  The support portion 80-4 of the structure type E4 shown in FIG. 5 includes five fixing members 84A, 84B, 84C, 84D, and 84E that are separated from each other in the X direction. Each of the fixing members 84A, 84B,..., 84E corresponds to the fixing members 83A, 83B,. The dimension in the X direction of each of the fixing members 84A, 84B,..., 84E is set to 10 mm, similar to the dimension in the X direction of the fixing members 83A, 83B,. The dimension in the Y direction of each of the fixing members 84A, 84B,..., 84E is set to 5.5 mm corresponding to ½ of the dimension in the Y direction of the fixing members 83A, 83B,. Moreover, the Z direction dimension of each fixing member 84A, 84B, ..., 84E is set to 3 mm corresponding to the Z direction dimension of the horizontal flow path 22.

  In this structure type E4, one end in the Y direction of each fixing member 84A, 84B,..., 84E (the end on the back side in FIG. 5) is one end in the Y direction of the horizontal plate portion 71 (the back side in FIG. 5). Edge). The other end in the Y direction of each fixing member 84A, 84B,..., 84E (the end on the near side in FIG. 5) is located in the center with respect to the Y direction of the horizontal plate portion 71.

  The table in FIG. 8 shows Examples 1, 2, 3, and 4 having the above-described structure types E1, E2, E3, and E4, and a comparative example having the structure type shown in FIG. The evaluation results when conducting a verification experiment are shown. In the structural type C1 of the comparative example, the dimensions of the horizontal plate portion 971 and the vertical plate portion 972 of the supply stabilization member 970 are the same as the dimensions of the horizontal plate portion 71 and the vertical plate portion 72 of the supply stabilization member 70, respectively. Is set. The dimension in the Z direction of the horizontal flow path 22 and the dimension in the Y direction of the vertical flow path 23 constituting the toner circulation flow path 20 are also set to the same conditions in each embodiment and the comparative example.

  Evaluation in the “image evaluation” column in the table was performed as follows.

  First, the developing devices of the Konica Minolta color laser printer (trade name: magiccolor 5570) were remodeled to the respective structure types C1, E1, E2, E3, and E4. Next, 2000 images with a printing rate of 1% were printed using each type of developing device (endurance test). By this durability test, it is considered that the toner in the developing device is appropriately deteriorated and is in a state suitable for evaluating the difference in the contact force of the supply stabilizing member with respect to the supply roller.

  Next, a halftone image was printed in a laboratory environment (temperature 23 ° C., humidity 65%) using each structure type developer after the durability test. This printing result was used as an evaluation target.

  In the “image evaluation” column, “longitudinal direction unevenness”, “circumferential direction unevenness”, “fixing member unevenness”, and “overall evaluation” are shown. “Longitudinal direction unevenness” and “circumferential direction unevenness” represent evaluation results for image unevenness in the X direction and Y direction, respectively. “Fixing member unevenness” represents an evaluation result of an image density difference between a portion where the horizontal plate portion 71 of the supply stabilization member 70 is supported by each fixing member of the support portion and a portion where the fixing member is not supported. The symbol “◎” representing the evaluation result indicates that there is no problem as an image and there is no unevenness. The symbol “◯” indicates that there is no problem as an image, but it is possible to confirm a slight unevenness. The symbol “Δ” indicates that there is no problem as an image, but that unevenness can be clearly confirmed. The symbol “x” indicates that there is a problem as an image.

  As can be seen from the evaluation result of “longitudinal direction unevenness”, in the structure type C1, the longitudinal direction unevenness was “x”, and a problem occurred (overall evaluation “x”). On the other hand, in the structure types E1, E2, E3, and E4, the longitudinal unevenness could be eliminated (longitudinal unevenness “◯”), and a stable image could be obtained (overall evaluation “◯”).

  In addition, in the structural types E1 and E2 having prismatic fixing members, the “fixing member unevenness” was “△” and “◯”, whereas in the structural types E3 and E4 having thin fixing members, both “Fixing member unevenness” was “◎”. The reason for this is that if the thickness of the fixing member (especially the dimension in the X direction) is increased, it becomes difficult for the toner to flow through the horizontal flow path 22 of the toner circulation channel 20. It can be explained that the toner flows well in the horizontal flow path 22 of the toner circulation flow path 20 through the gap between the fixing members.

  In addition, in the structure types E1 and E3 having the fixing member having a long Y direction dimension (corresponding to the Y direction dimension of the horizontal plate portion 71), the “circumferential unevenness” was “Δ”, whereas the Y direction dimension In the structure types E2 and E4 having a short fixing member (corresponding to 1/2 of the dimension in the Y direction of the horizontal plate portion 71), the “circumferential unevenness” was “◯”. The reason for this is that when passing through the horizontal flow path 22 of the toner circulation flow path 20, if the dimension in the Y direction of the fixing member becomes long, the section where the flow is blocked by the fixing member is long, so the toner does not flow easily. It can be explained that when the size is shortened, the toner flows well because the section where the flow is prevented by the fixing member is short. Moreover, in the structure types E2 and E4, the region where the fixing member is disposed below the horizontal plate portion 71 of the supply stabilizing member 70 is a section on the side farther from the developing roller 36 than the nip portion 76 in the Y direction. The section closer to the developing roller 36 than the nip portion 76 is a space. Therefore, the toner that has not adhered to the developing roller 36 at the nip portion 66 can easily enter the horizontal flow path 22 of the toner circulation flow path 20 first. Subsequently, the toner that has entered the horizontal flow path 22 flows through a gap between the fixing members disposed in a section farther from the developing roller 36 than the nip portion 76. Therefore, the toner can flow better through the horizontal flow path 22.

  The thin fixing member is not limited to the U-shaped fixing member shown in FIGS. 4, 5, and 6. For example, a step-like fixing member 87 shown in FIG. 7A or a U-shaped fixing member 88 shown in FIG. 7B may be employed. 7A includes a horizontal plate portion 871 to be attached to the inner wall of the housing 32, a vertical plate portion 873 extending upward from one end in the X direction of the horizontal plate portion 871, and the vertical plate portion 873. The horizontal plate portion 872 extends horizontally from the upper end of the plate and is to be attached to the lower surface of the horizontal plate portion 71 of the supply stabilizing member 70. 7 (b) includes a horizontal plate portion 881 to be attached to the lower surface of the horizontal plate portion 71 of the supply stabilizing member 70, a horizontal plate portion 882 to be attached to the inner wall of the housing 32, and these horizontal portions. It consists of a vertical plate portion 883 that connects the central portions in the X direction of the plate portions 881 and 882. When these fixing members 87 and 88 are provided, in particular, the Y-direction dimension of the fixing members 87 and 88 is set to a part (for example, 1/2) of the Y-direction dimension of the horizontal plate portion 71 of the supply stabilizing member 70, As in the structure type E4 shown in FIG. 5, the fixing members 87 and 88 are arranged in a region farther from the developing roller 36 than the nip portion 76 with respect to the direction with respect to the Y direction. When the area close to 36 is a space, the supply of toner from the supply roller 38 to the developing roller 36 can be stabilized and the image quality can be improved as in the structure type E4.

  FIG. 9 shows a support portion 80-5 configured integrally. The support portion 80-5 substantially has a plate-like horizontal plate portion 85 as a connecting portion extending in the X direction with the fixing members 84A, 84B, 84C, 84D, 84E of the structure type E4 shown in FIG. It is equivalent to what was integrally connected by. Specifically, the support portion 80-5 includes five horizontal plate portions 851 to be attached to the lower surface of the horizontal plate portion 71 of the supply stabilizing member 70, and five plate members formed by cutting up the plate material forming the horizontal plate portion 85. Support portions 85A, 85B, 85C, 85D, and 85E are provided. For example, as shown with respect to the support portion 85A, each support portion extends vertically from the horizontal plate portion 85, and extends horizontally from the upper end of the vertical plate portion 853. The horizontal plate portion 71 of the supply stabilizing member 70 It consists of a horizontal plate portion 851 to be attached to the lower surface. A cut and raised mark 859 of the horizontal plate portion 85 is a space.

  Since this support portion 80-5 is formed in a state where five support portions 85A, 85B, 85C, 85D, and 85E are connected by the horizontal plate portion 85, the supply stabilizing member 70 and the support portion 80-5 are connected to each other. Assembling can be easily performed at the stage of assembling. That is, the accuracy of the gap between the support portions can be ensured at the stage of forming the support portions 85A, 85B, 85C, 85D, and 85E. Therefore, in assembling the supply stabilizing member 70 and the support portion 80-5, it is not necessary to pay particular attention to the accuracy of the gap between the support portions.

  The supply stabilization member 70 and the support portion (fixing member) can be attached by various methods such as known welding and adhesion.

  In the structure types E1, E2, E3, and E4 shown in FIGS. 2, 3, 4, and 5, the number of fixing members arranged in the X direction is five, but the present invention is not limited to this. The number of the fixing members can be varied based on the balance between the longitudinal dimension of the supply stabilizing member 70 and the strength (flexibility), and can be set to 4 or less, or 6 or more, for example.

  In the above-described embodiment, the horizontal plate portion 71 of the supply stabilization member 70 is in contact with the supply roller 38 from below in a horizontal state. However, the present invention is not limited to this, and the horizontal plate portion 71 (particularly the upper surface thereof) of the supply stabilizing member 70 may be in contact with the supply roller 38 from below while being inclined with respect to the horizontal plane.

  In the above-described embodiment, the support portion is supported by, for example, the inner wall of the housing, but is not limited thereto. The support portion may be supported by a component formed integrally with the inner wall of the housing.

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

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 structural type of the support part which supports the supply stabilization member of the said developing device. It is a figure which shows another structure type of the support part which supports the supply stabilization member of the said developing device. It is a figure which shows another structure type of the support part which supports the supply stabilization member of the said developing device. It is a figure which shows another structure type of the support part which supports the supply stabilization member of the said developing device. It is a figure which shows the fixing member which comprises the support part of FIG. 4 in detail. (A), (b) is a figure which shows the modification of the said fixing member, respectively. It is a figure which shows the evaluation result of the verification experiment conducted about the said developing device. It is a figure which shows another structure type of the support part which supports the supply stabilization member of the said developing device. It is a figure which shows the place which looked at the conventional supply stabilization member from diagonally downward with the supply roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Developing device 20 Toner circulation flow path 32 Housing 36 Developing roller 38 Supply roller 70 Supply stabilization member

Claims (7)

A housing;
A developing roller extending horizontally in the opening of the housing;
A supply roller that is pressed in parallel with the developing roller in the housing to form a first nip portion, and rotates to supply toner to the developing roller;
Supplying toner from the supply roller to the developing roller, which is installed in the housing, forms a second nip portion in contact with a portion of the supply roller that is upstream of the first nip portion in the rotational direction. A supply stabilizing member for regulating the amount,
A portion of the supply stabilizing member that forms the second nip portion is formed in a plate shape that extends in a longitudinal direction along the axial direction of the supply roller and exhibits flexibility,
Of the second surface opposite to the first surface forming the second nip portion of the plate-like portion of the supply stabilizing member, the supply is provided at least inside the end portions other than both ends with respect to the longitudinal direction. A developing device comprising a support portion for supporting the plate-like portion against pressure from a roller. A housing containing non-magnetic single component toner;
A developing roller extending horizontally in the opening of the housing;
A supply roller that is pressed in parallel with the developing roller in the housing to form a first nip portion, rotates in the same direction as the developing roller, and supplies toner to the developing roller;
A toner is installed in the housing and forms a second nip portion in contact with a lower portion of the supply roller on the upstream side in the rotation direction than the first nip portion, and the toner from the supply roller to the developing roller A supply stabilizing member that regulates the supply amount of the developing roller, and the supply stabilizing member includes a portion below the first nip portion of the developing roller and a first nip portion of the supply roller. Extends from the substantially triangular first region sandwiched between the lower portion to the opposite side of the first region with respect to the second nip portion,
The supply stabilization on the side opposite to the first region with respect to the second nip portion from the first region and below the supply stabilization member due to the pressure of the toner to be accumulated in the first region. A toner circulation channel that pushes the toner back to a second region corresponding to the upper part of the member;
The portion of the supply stabilizing member that forms the second nip portion is formed in a plate shape that extends in the longitudinal direction along the axial direction of the supply roller and exhibits flexibility,
Of the second surface opposite to the first surface forming the second nip portion of the plate-like portion of the supply stabilizing member, the supply is provided at least inside the end portion other than both ends with respect to the longitudinal direction. A developing device comprising a support portion for supporting the plate-like portion against pressure from a roller. The developing device according to claim 1 or 2,
The developing device according to claim 1, wherein a plurality of the support portions are provided apart from each other inside the second surface of the supply stabilizing member except for both end portions in the longitudinal direction. The developing device according to claim 1 or 2,
The developing device according to claim 1, wherein the support portion is configured such that a dimension in the longitudinal direction is smaller than a dimension in the other direction. The developing device according to claim 1 or 2,
The support portion is disposed in a region corresponding to a part of the plate-like portion with respect to a short direction perpendicular to the longitudinal direction in a plane along the plate-like portion of the supply stabilizing member. A developing device. The developing device according to claim 5.
With respect to the short direction, the region where the support portion is disposed is a section farther from the developing roller than the second nip portion, and is closer to the developing roller than the second nip portion. The developing device characterized in that the side section is a space. The developing device according to claim 3,
A developing device comprising a plate-like connecting portion that integrally connects the plurality of support portions in parallel with the plate-like portion of the supply stabilizing member.

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