JP2014186237A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a one-component developer on the side of a first chamber from becoming excessive, while stirring the one-component developer supplied to a supply member supplying the powder one-component developer to a developer holding member, in a developer container in which the supply member is arranged.SOLUTION: A developing device 100 includes a housing 102 including a developing roll 104 and a supply roll 106, a stirring bar 110 reciprocated between a first position P1 and a second position P2 in the housing 102, and a driving part 120 driving the stirring bar 110. At this time, the stirring bar 110 is moved from the first position P1 to the second position P2, so that a part of toner T pushed away by the stirring bar 110 is recirculated to the side of a replenishment chamber 105 from the side of a developing chamber 103. Thus, the toner T on the side of the developing chamber 103 can be prevented from becoming excessive, while stirring the toner T supplied to the supply roll 106.

Description

  The present invention relates to a developing device and an image forming apparatus.

  The developing device of Patent Document 1 has a developer container and a toner container, and the toner supplied from the toner container through the toner supply port is conveyed by the developing sleeve and supplied to the photosensitive drum. The The toner container is provided with an agitator to which a toner blocking prevention member is attached. A toner blocking loosening member that swings when the toner blocking preventing portion comes into contact with the toner replenishing port is provided.

  The developing device of Patent Document 2 includes a developing roll, a supply roll for supplying toner to the developing roll, a toner storage unit provided above the supply roll, and a plate-like member between the toner storage unit and the supply roll And a stirring unit that stirs the toner. Furthermore, the developing device of Patent Document 2 has a link mechanism that operates the stirring unit.

JP 2005-202234 A JP 2012-88403 A

  The present invention provides a developer container in which a supply member for supplying a one-component developer in powder form to a developer holding member is disposed, while stirring the one-component developer supplied to the supply member, It is an object of the present invention to obtain a developing device and an image forming apparatus that can suppress an excessive amount of component developer.

  According to a first aspect of the present invention, there is provided a developing device for supplying a one-component developer in powder form to a developer holding member, and a first member in which the supply member is rotatably disposed and contains the one-component developer. A developer container comprising: one chamber; and a second chamber formed by separating a wall portion of the first chamber and containing the one-component developer supplied to the first chamber; and the supply member A first position outside the one-component developer housed in the developer container on the second chamber side of the supply member in a plane orthogonal to the axial direction, the first position and the wall portion A moving member that is reciprocally movable to a second position inside the one-component developer housed in the developer container on the supply member side, and driving the moving member to move the moving member. Driving means for reciprocating the first position and the second position, and the moving section By the movement of, the one-component developer than said wall portion to move from the first chamber side to the second chamber side.

  In the developing device according to a second aspect of the present invention, the second position is a common tangent line between the movable member and the supply member at the first position, and the movable member and the supply member have the common tangent line. It is provided on the opposite side to the supply member side of the common tangent line drawn so as to be arranged on the opposite side with respect to it.

  In the developing device according to a third aspect of the present invention, the moving member has a shape that narrows toward the tip when viewed in the moving direction to the second position.

  In the developing device according to a fourth aspect of the present invention, the moving member has a rear end surface spreading in a direction intersecting the moving direction on the rear side when viewed in the moving direction to the second position. .

  The developing device according to claim 5 of the present invention is the one-component developer in which the moving member is entirely accommodated in the developer container as the moving member moves between the first position and the second position. Pass the top of the.

  In the developing device according to a sixth aspect of the present invention, as the moving member moves between the first position and the second position, the height of the upper end of the wall surface on the first chamber side in the wall portion is increased. It has a part that passes through the position.

  In the developing device according to a seventh aspect of the present invention, the second chamber is provided with a conveying member that conveys the one-component developer in the second chamber to the first chamber, and the driving unit includes the conveying member. Moves the moving member from the first position to the second position after the one-component developer has been conveyed to the first chamber.

  8. The image forming apparatus according to claim 8 of the present invention, wherein the latent image held by the image carrier is developed with a one-component developer to form a developer image. And a transfer means for transferring the developer image of the image carrier to a recording medium.

  According to the first aspect of the present invention, in the developer container in which the supply member for supplying the one-component developer powder is supplied to the developer holding member, the supply member 1 is supplied to the supply member as compared with the case where no moving member is provided. It is possible to suppress an excess of the one-component developer on the first chamber side while stirring the component developer.

  The invention according to claim 2 is such that the moving member is opposite to the supply member side of the common tangent line arranged on the opposite side to the supply member side among the common tangent line between the first position and the supply member at the first position. It is possible to suppress a decrease in the fluidity of the one-component developer supplied to the supply member as compared with the configuration that does not move to the second position.

  According to the third aspect of the present invention, the stirring force for stirring the one-component developer can be increased as compared with the configuration having the moving member having the same shape toward the tip as viewed in the moving direction to the second position.

  According to the fourth aspect of the present invention, the developer conveying force to the second chamber can be increased as compared with a configuration that does not have a rear end surface that extends in a direction intersecting the moving direction.

  According to the fifth aspect of the present invention, as compared with a configuration in which the entire moving member does not pass through the upper end of the one-component developer with the movement between the first position and the second position, The conveyance force can be increased.

  According to the sixth aspect of the present invention, it is possible to suppress the developer contained in the first chamber from being compressed as compared with a configuration having a moving member that does not pass through the height position of the upper end of the wall surface on the first chamber side. it can.

  According to the seventh aspect of the present invention, the supply amount of the one-component developer to the supply member is larger than that of the structure having the moving member that moves to the second position when the conveyance member conveys the one-component developer to the first chamber. Decrease can be suppressed.

  According to the eighth aspect of the present invention, image defects due to insufficient supply of the developer can be suppressed as compared with a configuration having a developing device that does not stir the developer supplied to the supply member.

1 is an overall configuration diagram of an image forming apparatus according to a first embodiment. 1 is a longitudinal sectional view of a developing device according to a first embodiment. It is a schematic diagram of the drive part which drives the stirring rod which concerns on 1st Embodiment. (A), (B), (C) It is a schematic diagram which shows the movable range of the stirring rod which concerns on 1st Embodiment. (A), (B), (C) It is explanatory drawing which shows the operation state of the stirring rod which concerns on 1st Embodiment. It is a graph which shows the relationship between the outer diameter and moving speed of the stirring rod which concerns on 1st Embodiment. It is a schematic diagram which shows the stirring function of the stirring rod which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the developing device according to the second embodiment. (A), (B) It is explanatory drawing which shows the operation state of the stirring rod which concerns on 2nd Embodiment. FIG. 6C is a schematic diagram illustrating a stirring function and a toner collecting function of the stirring rod according to the second embodiment.

[First embodiment]
An example of the developing device and the image forming apparatus according to the first embodiment will be described.

(overall structure)
FIG. 1 shows an image forming apparatus 10 as an example of the first embodiment. The image forming apparatus 10 includes a housing 11 in which each component is accommodated. In the housing 11, a plurality of paper storage units 12 that store recording paper P as an example of a recording medium, an image forming unit 20 that forms a toner image TZ (an example of a developer image) on the recording paper P, and A paper transport unit 14 that transports the recording paper P from the paper storage unit 12 to the discharge unit 18 is provided.

  Further, inside the casing 11, a fixing device 40 that fixes the toner image TZ formed on the recording paper P by the image forming unit 20 to the recording paper P, and a control that controls the operation of each part of the image forming device 10. Part 30 is provided. Furthermore, a discharge unit 18 for discharging the recording paper P on which the image is fixed by the fixing device 40 is provided at the upper part of the housing 11.

  In the following description, the direction indicated by the arrow Z in FIG. 1 is the device height direction, and the direction indicated by the arrow X is the device width direction. In addition, a direction (indicated by an arrow Y) orthogonal to the device height direction and the device width direction is defined as the device depth direction. When the image forming apparatus 10 is viewed from the side where a user (not shown) stands (when viewed from the front), the apparatus height direction, the apparatus width direction, and the apparatus depth direction are described as a Z direction, an X direction, and a Y direction.

  Further, when it is necessary to distinguish one side and the other side in the X direction, the Y direction, and the Z direction, respectively, when the image forming apparatus 10 is viewed from the front, the upper side is + Z side, the lower side is -Z side, and the right side is The + X side, the left side is described as -X side, the back side is described as + Y side, and the front side is described as -Y side.

  As an example, the paper transport unit 14 includes a transport path 15 that extends from the −Z side to the + Z side on the + X side of the image forming apparatus 10 and transports the recording paper P. The paper transport unit 14 also feeds the recording paper P stored in each paper storage unit 12 to the transport path 15, and the recording paper P disposed along the transport path 15 and sent out by the transport roll 16. Are transported to a transfer position Q, which will be described later. Further, the paper transport unit 14 has a discharge roll 48 that discharges the recording paper P to the discharge unit 18 at the downstream end in the transport direction of the recording paper P in the transport path 15.

  Further, on the + X side of the transport path 15 in the housing 11, a reverse transport path 37 that reverses the recording paper P with the toner image TZ fixed on one side (front surface) and sends it back to the transfer position Q is provided. ing. Then, when the toner image TZ is formed on both sides of the recording paper P in the image forming apparatus 10, the recording paper P having the toner image TZ fixed on one side is switched back by the discharge roll 48 to the reverse conveyance path 37. It is guided and sent back to the transfer position Q again.

(Image forming part)
The image forming unit 20 includes a photoconductor 22 as an example of an image holding body that holds a latent image (not shown). A charging device 24, an exposure device 26, a developing device 100, a transfer roll 28 as an example of a transfer unit, and a cleaning blade 29 are provided around the photoconductor 22 in order from the upstream side in the rotation direction of the photoconductor 22. It has been.

  The photosensitive member 22 is formed in a cylindrical shape, and is driven to rotate around its own axis with the Y direction as an axial direction by a driving unit (not shown). As an example, a photosensitive layer (not shown) having a negative charging polarity is formed on the outer peripheral surface of the photoreceptor 22. The photosensitive member 22 has an inner base (not shown) grounded. When the image forming apparatus 10 is viewed from the -Y side to the + Y side, the rotation direction of the photosensitive member 22 is a counterclockwise direction (hereinafter referred to as -R direction). The photoreceptor 22 may have a configuration in which an overcoat layer is formed on the outer peripheral surface.

  As an example, the charging device 24 is disposed so as to face the outer peripheral surface of the photoconductor 22 and charges the outer peripheral surface (photosensitive layer) of the photoconductor 22 to a negative polarity. In this embodiment, as an example, the charging device 24 is a corona discharge type (non-contact charging type) corotron charging device.

  The exposure device 26 forms a latent image on the outer peripheral surface of the photosensitive member 22 based on the image signal sent from the control unit 30. Examples of the image signal sent from the control unit 30 include an image signal acquired by the control unit 30 from an external device. Details of the developing device 100 will be described later.

  The transfer roll 28 is disposed opposite the photoconductor 22 with the conveyance path 15 interposed between the photoconductor 22 and the transfer roll 28. Further, as an example, a voltage having a polarity opposite to the charging polarity of the toner T is applied to the transfer roll 28 from a power source (not shown), and a potential difference is formed between the transfer roll 28 and the photosensitive member 22. The transfer roll 28 is configured to convey the recording paper P to the + Z side (downstream of the conveying path 15) with the recording paper P sandwiched between the photoreceptor 22. Between the transfer roll 28 and the photosensitive member 22, a transfer position Q at which an image (developer image) formed on the photosensitive member 22 is transferred to the recording paper P is set.

  The fixing device 40 includes a heating roll 42 and a pressure roll 44. In the fixing device 40, the toner image TZ transferred to the recording paper P is fixed to the recording paper P by heating by the heating roll 42 and pressing by the pressure roll 44. Further, the above-described discharge roll 48 is provided on the + Z side (downstream in the transport direction) of the fixing device 40.

  A toner cartridge 32 that contains toner T is provided on the −X side of the exposure device 26. A toner transport unit (not shown) that transports the toner T from the toner cartridge 32 toward the developing device 100 is provided between the toner cartridge 32 and the developing device 100.

(Image forming operation)
Next, an image forming operation in the image forming apparatus 10 will be described.

  As shown in FIG. 1, in the image forming apparatus 10, the recording paper P sent out from any one of the paper storage portions 12 by the sending roll 16 is sent to the transfer position Q by a plurality of transport rolls 17.

  On the other hand, in the image forming unit 20, the photosensitive member 22 is charged by the charging device 24 and then exposed by the exposure device 26, and an electrostatic latent image is formed on the outer peripheral surface of the photosensitive member 22. Then, the electrostatic latent image is developed by the developing device 100, whereby a black toner image TZ is formed on the photoreceptor 22 as an example. The black toner image TZ is transferred to the recording paper P by the transfer roll 28 at the transfer position Q.

  The recording paper P to which the toner image TZ has been transferred is conveyed to the fixing device 40, and the toner image TZ is fixed to the recording paper P by the fixing device 40. When the toner image TZ is formed only on one side of the recording paper P, the recording paper P is discharged to the discharge unit 18 by the discharge roll 48 after the toner image TZ is fixed.

  When the toner image TZ is formed on both sides of the recording paper P, after the toner image TZ is formed on one side, the recording paper P is switched back and conveyed by the discharge roll 48 and sent to the reverse conveyance path 37. Further, the recording paper P is sent again from the reverse conveyance path 37 to the transfer position Q, and the toner image TZ is formed on the opposite surface (back surface) where the toner image TZ is not recorded in the same manner as described above. It is discharged to the discharge unit 18. As described above, a series of image forming operations of the image forming apparatus 10 is performed.

(Main part configuration)
Next, the developing device 100 will be described.

  As illustrated in FIG. 2, the developing device 100 includes a housing 102 as an example of a developer container, a developing roll 104 as an example of a developer holding member, and an example of a supply member that supplies toner T to the developing roll 104. The supply roll 106 is provided. Further, the developing device 100 is a stirrer 110 as an example of a moving member capable of reciprocating movement within the housing 102, and between the first position P1 and the second position P2 described later by driving the stirrer 110. And a driving unit 120 as an example of a driving means for reciprocating movement.

(toner)
The toner T is an example of a powdery one-component developer, and the toner T particles have a polyester resin that is negatively charged and are formed by emulsion polymerization. The toner T is accommodated in the housing 102. The one-component developer means a developer that is developed without using a carrier such as a two-component developer. In addition to the thermoplastic resin as a main component, a pigment, a charge control agent, a release agent. It is a concept that includes additives such as molds. The toner T is schematically shown as a circle (actually a sphere) in each cross-sectional view, but is not limited to a sphere such as a polymerized toner, but may be an indefinite shape such as a pulverized toner.

<Housing>
The housing 102 has bottom walls 102A that are curved at two locations so as to be convex in the −Z direction when viewed in the Y direction. A side wall 102 </ b> B that stands upright along the Z direction is provided at the −X side end of the bottom wall 102 </ b> A. In addition, an extending portion 102 </ b> C extending toward the photoconductor 22 is formed at the end portion on the + X side of the bottom wall 102 </ b> A.

  Further, on the + Z side (upper side) of the supply roll 106, a side wall 102G that faces the side wall 102B in the X direction and has the same height as the + Z side end of the side wall 102B is provided. The height of the side wall 102G in the Z direction is lower than the height of the side wall 102B in the Z direction. In addition, a side wall 102D that stands upright along the Z direction is provided on the + Y side of the bottom wall 102A, and a side wall 102E that stands up along the Z direction is provided on the −Y side of the bottom wall 102A. Yes.

  A partition wall 102F as an example of a wall projecting toward the + Z side is formed integrally with the bottom wall 102A at the center in the X direction (two curved joints) of the bottom wall 102A. The partition wall 102F has an isosceles triangular XZ cross section and a triangular prism shape that is long in the Y direction, and a lower portion (−Z side) of the housing 102 is connected to a developing chamber 103 as an example of a first chamber to be described later. And a replenishment chamber 105 as an example of the second chamber.

(Development room)
The developing chamber 103 is formed closer to the supply roll 106 than the partition wall 102F. In the developing chamber 103, a developing roll 104 and a supply roll 106 are provided so as to be rotatable in the + R direction with the Y direction as an axial direction. Specifically, two bearing members (not shown) are respectively attached to the side walls 102D and 102E, and both end portions of the shaft portion 104A of the developing roll 104 and both ends of the shaft portion 106A of the supply roll 106 are attached to these bearing members. The part is supported. Gears (not shown) are attached to the ends of the shafts 104A and 106A, and the shafts 104A and 106A are driven to rotate by a motor (not shown).

  As an example, the developing roll 104 is formed of a silicon rubber roll, and −160 [V] is applied to the shaft portion 104A from a power source (not shown) as a DC voltage. Further, as an example, the developing roll 104 is disposed so as to be in contact with the supply roll 106 at a position + X side and a position + Z side (an oblique 45 ° position) with respect to the supply roll 106 when viewed from the + Y side. . A part of the outer peripheral surface of the developing roll 104 is exposed to the photosensitive member 22 side from between the extended portion 102C and the side wall 102G.

  The supply roll 106 is disposed at the deepest portion of the developing chamber 103 in the X direction so that the outer peripheral surface faces the + Z side surface of the bottom wall 102A. Moreover, the supply roll 106 is comprised by the urethane foam sponge roll as an example. Further, the supply roll 106 forms a nip portion that sandwiches the toner T together with the developing roll 104, and supplies the toner T to the developing roll 104.

  As shown in FIG. 4A, the amount of toner T supplied to the supply roll 106 is limited to the position −X side and + Z side of the supply roll 106 when the developing chamber 103 is viewed on the + Y side. A restriction block 107 is provided. The limiting block 107 includes a curved surface 107A facing the outer peripheral surface of the supply roll 106, and a curved surface 107B facing the inner wall surface 102H (an example of a wall surface) on the developing chamber 103 side of the bottom wall 102A. ).

  The curved surface 107 </ b> A has a shape that is recessed toward the outer side in the radial direction of the supply roll 106 with substantially the same curvature as the outer peripheral surface of the supply roll 106 as viewed in the XZ section. Further, the curved surface 107A is formed on a substantially circular arc of ¼ from 9 o'clock to 12 o'clock when the + Z side upper end of the supply roll 106 is viewed clockwise from 12 o'clock.

  The curved surface 107B is convex toward the inner wall surface 102H with substantially the same curvature as the inner wall surface 102H when viewed in the XZ section. The curved surface 107A is formed from the −Z side end (lower end) of the curved surface 107A to the −Z side end of the −X side side surface 107C of the restriction block 107. A supply path 112 through which the toner T (see FIG. 2) is supplied toward the supply roll 106 is between the inner wall surface 102H and the curved surface 107B. That is, the supply path 112 is formed between the partition wall 102 </ b> F and the supply roll 106.

  As shown in FIG. 2, the + Z side portion of the regulating blade 109 extending along the YZ plane is attached to the inner wall surface of the side wall 102G. For example, the restriction blade 109 is formed of a rectangular SUS plate. The regulating blade 109 extends from the −Z side end of the side wall 102 </ b> G toward the outer peripheral surface of the developing roll 104 as viewed in the XZ plane, and the −Z side end extends from the outer peripheral surface of the developing roll 104. In contact. The regulating blade 109 regulates the thickness in the radial direction of the toner T held on the outer peripheral surface of the developing roll 104.

(Supply room)
The replenishment chamber 105 is formed on the side opposite to the developing chamber 103 side of the partition wall 102F. In the replenishing chamber 105, a replenishment paddle 108 as an example of a transport member is provided so as to be rotatable in the −R direction with the Y direction as an axial direction. Specifically, bearing members (not shown) are attached to the side walls 102D and 102E, and both end portions of the shaft portion 108A of the supply paddle 108 are supported by these bearing members. A gear (not shown) is attached to the end of the shaft portion 108A, and the rotational force of the gear of the supply roll 106 is transmitted to this gear.

  The supply paddle 108 has a plate-like portion 108B extending in the radial direction of the shaft portion 108A. The tip of the plate-like portion 108B (the side opposite to the shaft portion 108A side) is in contact with the inner wall surface 102J (see FIG. 4A) of the bottom wall 102A of the supply chamber 105. As a result, when the replenishment paddle 108 rotates in the −R direction, the toner T accommodated in the replenishment chamber 105 is picked up by the plate-like portion 108 </ b> B and conveyed to the developing chamber 103.

(Stir bar)
As shown in FIG. 3, as an example, the stirring rod 110 is formed in a columnar shape having the Y direction as an axial direction, and has a shaft portion 110 </ b> A having a smaller diameter at both ends in the axial direction than the center in the Y direction. Is formed. The shaft portions 110A at both ends protrude outward from the guide holes 111 formed in the side walls 102D and 102E of the housing 102.

  One end portion of the stirring rod 110 in the axial direction is fixed to a crank 126 of the drive unit 120 described later. Thereby, the stirring rod 110 is configured to reciprocate between the first position P1 and the second position P2 when the drive unit 120 is operated. In the following description, the moving direction of the stirring bar 110 is referred to as the M direction, the side where the stirring bar 110 approaches the supply roll 106 (see FIG. 2) is the + M side, and the side where the stirring bar 110 is separated from the supply roll 106. -It describes as the M side.

  The guide hole 111 penetrates the side walls 102D and 102E in the Y direction. Further, the guide hole 111 is a long hole extending obliquely so that the lower end is positioned on the −Z side toward the + X side, and the width in a direction orthogonal to the direction (M direction) in which the guide hole 111 extends. Is slightly larger than the diameter of the shaft portion 110A. The first position P1 and the second position P2 are determined based on the movement range of the crank 126 described later. The first position P1 is on the + Z side of the guide hole 111, and the second position P2 is on the -Z side of the guide hole 111. In addition, the 1st position P1 and the 2nd position P2 are shown by the center position in the XZ cross section of the stirring rod 110 (in the surface orthogonal to the axial direction of the supply roll 106 (refer FIG. 2)).

  As shown in FIG. 4C, the first position P1 is outside the toner T (see FIG. 2). Further, the partition wall 102F (inner wall surface 102H) is set to the −X side from the broken line A passing through the point P3 which is the height position of the upper end in the Z direction and extending along the Z direction, and to the + Z side from the point P3. Yes. For this reason, when the stirring rod 110 is stationary (stopped) at the first position P1, the end portion on the −X side of the stirring rod 110 enters the supply chamber 105 side by Δd1 from the broken line A.

  As shown in FIG. 4B, the second position P2 is located on the −Z side with respect to the broken line B extending along the X direction through the point P3 and on the + X side with respect to the point P3. For this reason, when the stirring rod 110 is stationary (stopped) at the second position P2, the end of the stirring rod 110 on the −Z side enters the developing chamber 103 side (within the supply path 112) by Δd2 from the broken line B. ing.

  As shown in FIG. 4A, the second position P2 is inside the toner T (see FIG. 2) on the supply roll 106 side than the first position P1. Further, the second position P2 includes the stirring bar 110 on the opposite side of the supply roll 106 side of the common tangent line between the outer peripheral surface of the stirring bar 110 and the outer peripheral surface of the supply roll 106 arranged at the first position P1. The common tangent line K to be arranged is set on the side opposite to the supply roll 106 side.

(Drive part)
As shown in FIG. 3, as an example, the drive unit 120 includes a motor 122, a gear 124 that rotates by driving the motor 122, and a crank 126 that connects the gear 124 and the stirring rod 110. . The motor 122 is also used as a driving source for the developing roll 104, the supply roll 106, and the replenishment paddle 108 (see FIG. 2). The gear 124 is adapted to receive a driving force from a gear (not shown) of the replenishment paddle 108 via another gear (not shown). The drive unit 120 is switched on and off by the control unit 30 (see FIG. 3).

  As an example, one end of the crank 126 is connected to the −Y side of the outer periphery of the gear 124 so that the relative angle can be displaced by a pin 125. The other end in the longitudinal direction of the crank 126 is connected to the + Y side (outside the side wall 102D) of the shaft portion 110A of the stirring rod 110 so that the relative angle can be displaced. The pin 125 is formed in a cylindrical shape, and the axial direction is along the Y direction. Thus, when the motor 122 rotates the gear 124, the rotational movement of the gear 124 is converted into the reciprocating movement of the stirring rod 110 in the M direction.

  As shown in FIG. 2, in the developing device 100, when the replenishment paddle 108 transports the toner T to the developing chamber 103, the stirring rod 110 moves from the second position P2 (see FIG. 4A) to the first position P1. It is supposed to move. In the developing device 100, after the transport of the toner T to the developing chamber 103 in one rotation of the replenishment paddle 108 is completed, the stirring rod 110 moves from the first position P1 to the second position P2. .

(Function)
Next, the operation of the first embodiment will be described.

  As shown in FIGS. 5B and 5C, in the developing device 100, the stirring rod 110 reciprocates between the first position P1 and the second position P2 in accordance with the supply of the toner T by the replenishment paddle 108. . As the stirring rod 110 reciprocates between the first position P1 and the second position P2, the toner T accommodated in the developing chamber 103 (including the supply path 112) is stirred and becomes a lump. Therefore, the fluidity of the toner T supplied to the supply roll 106 is suppressed from being lowered.

  Further, since the first position P1 is outside the toner T and the second position P2 is inside the toner T, the stirring rod 110 moves from the first position P1 to the second position P2, so that the stirring rod 110 Part of the pushed toner T returns from the developing chamber 103 side to the replenishing chamber 105 side. This suppresses the toner T on the developing chamber 103 side from becoming excessive.

  As shown in FIG. 4A, in the developing device 100, the second position P2 is on the supply roll 106 side of the common tangent line K described above between the stirring rod 110 and the supply roll 106 at the first position P1. Is set on the opposite side. For this reason, when the stirring rod 110 moves from the first position P1 to the second position P2 inside the toner T, the stirring rod 110 does not move toward the supply roll 106. The toner T is hardly pinched. Thereby, aggregation of the toner T on the outer peripheral surface of the supply roll 106 is suppressed.

  Hereinafter, a detailed operation in the movement of the stirring rod 110 between the first position P1 and the second position P2 will be described.

  With the start of the image forming operation of the image forming apparatus 10 (see FIG. 1), as shown in FIG. 5A, in the developing apparatus 100, the replenishment paddle 108 rotates to develop the toner T in the replenishment chamber 105. Move to the chamber 103 side. In FIG. 5A, the highest height position of the toner T when the supply paddle 108 rotates to supply the toner T to the developing chamber 103 is indicated by a broken line TA.

  Here, the stirring rod 110 moves to the first position P1 until the tip of the replenishment paddle 108 reaches the vicinity of the first position P1 from the start of operation. For this reason, the stirring rod 110 does not obstruct the supply (supply) of the toner T to the developing chamber 103 by the supply paddle 108. As a result, in the developing device 100, the stirrer bar moves from the first position P1 to the second position P2 when the replenishment paddle 108 replenishes the toner T to the developing chamber 103, compared with the configuration in which the replenishing paddle 108 moves from the first position P1 to the second position P2. A decrease in the supply amount of toner T to (supply roll 106) is suppressed.

  Subsequently, as shown in FIG. 5B, when the toner T is supplied to the supply path 112 and the replenishment paddle 108 reaches the vicinity of the first position P1, the stirring rod 110 is moved from the first position P1 to the second position P2. Move to. At this time, the stirring rod 110 passes through the height position TA of the upper end of the toner T as it moves between the first position P1 and the second position P2. Furthermore, the stirring rod 110 moves to the second position P2 so that a part thereof passes through the height position (position P3) of the upper end of the inner wall surface 102H in the partition wall 102F.

  For this reason, the toner T supplied to the supply path 112 is conveyed to the supply roll 106 side and reaches the supply roll 106 as compared with the configuration without the stirring rod 110. As a result, in the developing device 100, even if image formation in which the amount of toner T to be used is increased is performed a plurality of times and the amount of toner T around the developing roll 104 may decrease, the toner T Is continuously supplied.

  Further, as shown in FIGS. 4B and 5B, a part of the stirring rod 110 moves to the second position P2 so as to pass the height position of the position P3, so that the stirring rod 110 An amount of toner T corresponding to the volume overflows (returns) to the supply chamber 105 side.

  Furthermore, as indicated by the hatched area S1 in FIG. 7, the stirring rod 110 has a tip end side (including the apex Ps) in the moving direction that is thinner than the central portion. For this reason, when the stirring bar 110 moves to the + M side, the toner T is pushed away in the direction intersecting the M direction by the outer peripheral surface 110B including the apex Ps. As a result, the stirring force of the toner T is higher in the stirring rod 110 than in the configuration in which the stirring rod 110 has the same cross-sectional shape toward the tip.

  By these actions (the reflux action and the stirring action of the toner T), in the developing device 100, the toner T is compressed (compressed) in the supply path 112 as compared with the configuration in which the toner T does not overflow to the replenishment chamber 105 side. ) Is suppressed.

  Subsequently, as shown in FIGS. 4C and 5C, the stirring rod 110 embedded in the toner T moves toward the first position P1 as the supply paddle 108 (see FIG. 2) rotates. Move. Since the first position P1 is closer to the replenishment chamber 105 than the point P3, a part of the toner T covered with the stirring rod 110 returns (moves) to the replenishment chamber 105 side beyond the partition wall 102F. Is done. As a result, the toner T overflowing in the developing chamber 103 is suppressed from returning to the developing chamber 103 again. Then, the amount of toner T in the developing chamber 103 is stabilized, and the toner T is suppressed from being compressed in the supply path 112.

  Subsequently, as shown in FIG. 2, the toner T held on the outer periphery of the supply roll 106 is rubbed and charged between the developing roll 104 and the supply roll 106. Since the supply roll 106 has a foam layer and is elastically deformed, the supply roll 106 is recessed along the outer peripheral surface of the developing roll 104, and then restored to the original circle when leaving the developing roll 104. The toner T on the supply roll 106 is separated from the supply roll 106 due to the increase in the linear velocity accompanying the restoration and the tensile force of the foam. Then, the charged toner T is held on the outer peripheral portion of the developing roll 104, the layer thickness is regulated by the regulating blade 109, and then conveyed to the developing area of the photoreceptor 22.

  Subsequently, as shown in FIG. 1, in the image forming apparatus 10, the above-described image forming operation (development process, transfer process, fixing process) is performed, and the toner image TZ is fixed on the recording paper P. Here, in the developing device 100, a decrease in the fluidity of the toner T is suppressed, so that in the image forming device 10, an amount of toner T necessary for image formation is secured, and image defects due to insufficient supply of the toner T occur. It is suppressed.

  Here, in the image forming apparatus 10, the outer diameter [mm] of the stirrer bar 110 and the number of reciprocations per minute of the stirrer bar 110 (reciprocal speed) that suppresses image defects when 100% full surface image formation is performed. The graph shown in FIG. 6 was obtained. As can be seen from FIG. 6, it was confirmed that the required reciprocating speed could be reduced as the outer diameter of the stirring rod 110 was increased.

  Table 1 shows the toner T when the reciprocating speed of the stirring rod 110 is fixed at 2 [times / minute] and the outer diameter φ [mm] of the stirring rod 110 is changed to φ1, φ2, φ3, φ4, and φ5. The state of occurrence of image defects due to insufficient supply is shown. Note that in image evaluation 1, ten sheets of solid images were continuously formed in an environment of temperature 28 [° C.] and humidity 80 [%], and whether these ten image densities satisfy the set image density. Was measured with X-Rite 508 manufactured by X-Rite. The measurement results were ranked in three stages of ◯ × Δ. ○: In-plane density difference ≦ 0.2 (good), Δ: 0.2 <in-plane density difference <0.3 (no problem level), x: In-plane density difference ≧ 0.3 (bad).

  In image evaluation 2, 1000 sheets of a full blank image (full solid image) were continuously formed in an environment of a temperature of 28 ° C. and a humidity of 80%, and then a single character image was formed. It was formed and visually evaluated whether the characters were faint. The results were ranked in three stages (◯: good, Δ: no problem level, x: bad).

  In Table 1, it was found that as the outer diameter φ of the stirring rod 110 increases, the evaluation result of the image evaluation 1 becomes “good” and the evaluation result of the image evaluation 2 becomes “poor”. Further, it was found that by setting the outer diameter φ of the stirring rod 110 to 3 [mm], the results of the image evaluations 1 and 2 were both “good”.

  6 and Table 1, in the developing roll 104, the outer diameter is 12 [mm], the roughness Ra is 1.2 [μm], the outer diameter of the shaft portion 104A is 5 [mm], and the applied voltage is DC-160 [V]. The supply roll 106 has an outer diameter of 11 [mm], an average cell diameter of 300 [μm], an Asker C hardness of 20 °, an outer diameter of the shaft portion 106A of 5 [mm], and an applied voltage of DC-160 [ V]. Further, the plate thickness of the regulating blade 109 was 0.08 [mm], and the linear pressure was 40 [N / m]. In addition, the width of the supply path 112 (interval between the inner wall surface 102H and the curved surface 107B) is 5 [mm], and the moving distance of the stirring rod 110 (one way from the first position P1 to the second position P2) is 5 [mm]. The average particle diameter of the toner T was 6.5 [μm].

[Second Embodiment]
Next, an example of a developing device and an image forming apparatus according to the second embodiment of the present invention will be described. Note that the same reference numerals as those in the first embodiment are given to the same members and parts as those in the first embodiment described above, and the description thereof is omitted.

  FIG. 8 shows a developing device 130 as an example of the second embodiment. The developing device 130 is provided in place of the developing device 100 (see FIG. 1) in the image forming apparatus 10 (see FIG. 1) of the first embodiment. The developing device 130 is provided with a stirring bar 132 as an example of a moving member in place of the stirring bar 110 (see FIG. 2). In the developing device 130, the other members and parts other than the stirring bar 132 have the same configuration as the developing device 100.

  The stirrer 132 is formed in a triangular prism shape having a triangular XZ cross section and extending in the Y direction. Then, both end portions of the stirring bar 132 protrude outward from the side walls 102D and 102E through the guide holes 111 (see FIG. 3), and the first position P1 and the second position P2 (see FIG. 9A) by the drive unit 120. Reciprocating movement between and the reference).

  As shown in FIG. 9C, the stirring bar 132 is narrowed toward the vertex C1 (tip) when viewed in the M direction (the moving direction in the second position P2 (see FIG. 9A)). The vertex C1 moves along the M direction. As an example, the apex angle corresponding to the vertex C1 is an acute angle. In addition, the stirring bar 132 has a rear end surface 132A that extends in a direction intersecting the M direction (an orthogonal direction as an example) on the side opposite to the vertex C1 side.

  Furthermore, in the state where the stirring bar 132 is disposed at the first position P1 (see FIG. 9A), the vertex C2 that is the end point on the + X side of the rear end surface 132A is on the common tangent line K of the first embodiment. Has been placed. And the stirring bar 132 is arrange | positioned in the 2nd position P2 on the opposite side to the supply roll 106 side of the common tangent K. As shown in FIG.

(Function)
Next, the operation of the second embodiment will be described.

  As shown in FIGS. 9A and 9B, in the developing device 130, the stirrer 132 reciprocates between the first position P1 and the second position P2 in accordance with the supply of the toner T by the replenishment paddle 108. . As the stirring rod 132 reciprocates between the first position P1 and the second position P2, the toner T stored in the developing chamber 103 (including the supply path 112) is stirred and becomes a lump. Therefore, the fluidity of the toner T supplied to the supply roll 106 is suppressed from being lowered.

  Further, since the first position P1 is outside the toner T and the second position P2 is inside the toner T, the stirring bar 132 moves from the first position P1 to the second position P2, so that the stirring bar 132 moves. Part of the pushed toner T returns from the developing chamber 103 side to the replenishing chamber 105 side. This suppresses the toner T on the developing chamber 103 side from becoming excessive.

  Further, the second position P2 is set on the opposite side to the supply roll 106 side of the common tangent line K described above between the stirring bar 132 and the supply roll 106 at which the second position P2 is at the first position P1. . For this reason, when the stirring bar 132 moves from the first position P1 to the second position P2 inside the toner T, the stirring bar 132 does not move toward the supply roll 106. The toner T is hardly pinched. Thereby, aggregation of the toner T on the outer peripheral surface of the supply roll 106 is suppressed.

  Hereinafter, a detailed operation in the movement of the stirring bar 132 between the first position P1 and the second position P2 will be described.

  With the start of the image forming operation of the image forming apparatus 10 (see FIG. 1), as shown in FIG. 9A, in the developing device 130, the replenishment paddle 108 rotates to develop the toner T in the replenishment chamber 105. Move to the chamber 103 side. In FIG. 9A, the highest height position of the toner T when the supply paddle 108 rotates to supply the toner T to the developing chamber 103 is indicated by a broken line TA.

  Here, the stirring bar 132 moves to the first position P1 from the start of operation until the tip of the replenishment paddle 108 reaches the vicinity of the first position P1. For this reason, the stirring rod 132 does not obstruct the supply (supply) of the toner T to the developing chamber 103 by the supply paddle 108. Thereby, in the developing device 130, the stirrer bar moves from the first position P1 to the second position P2 when the replenishment paddle 108 replenishes the toner T to the developing chamber 103, compared with the configuration in which the replenishing paddle 108 moves from the first position P1 to the second position P2. A decrease in the supply amount of toner T to (supply roll 106) is suppressed.

  Subsequently, when the toner T is supplied to the supply path 112 and the replenishment paddle 108 reaches the vicinity of the first position P1, the stirring rod 132 moves from the first position P1 to the second position P2. At this time, the stirring rod 132 passes through the height position TA of the upper end of the toner T as it moves between the first position P1 and the second position P2. Further, the stirring bar 132 moves to the second position P2 so that a part thereof passes the above-described position P3.

  Therefore, the toner T supplied to the supply path 112 is transported to the supply roll 106 side and reaches the supply roll 106 as compared with the configuration without the stirring bar 132. As a result, in the developing device 130, even if image formation in which the amount of toner T to be used is increased is performed a plurality of times and the amount of toner T around the developing roll 104 may decrease, the toner T Is continuously supplied.

  In addition, by moving a part of the stirring bar 132 to the second position P2 so as to pass the height position of the position P3, an amount of toner T corresponding to the volume of the stirring bar 132 overflows to the replenishment chamber 105 side ( Reflux).

  Subsequently, as shown in FIG. 9B, the stirring bar 132 embedded in the toner T moves toward the first position P1. Since the first position P1 is closer to the replenishing chamber 105 than the point P3, a part of the toner T covered with the stirring rod 132 returns (moves) to the replenishing chamber 105 side beyond the partition wall 102F. Is done. As a result, the toner T overflowing in the developing chamber 103 is suppressed from returning to the developing chamber 103 again. Then, the amount of toner T in the developing chamber 103 is stabilized, and the toner T is suppressed from being compressed in the supply path 112.

  Here, as shown in FIG. 9C, when the stirrer 132 moves to the + M side, the tip end side in the moving direction of the stirrer 132 is narrowed, so that the toner T has the side surface 132B including the vertex C1. , 132C. As a result, the stirring force of the toner T increases as compared with the configuration in which the stirring bar 132 has a stirring bar having the same cross-sectional shape toward the tip.

  Further, when the stirring bar 132 moves to the −M side, the rear end surface 132A spreads in a direction intersecting the moving direction, and thus the toner T is scooped up by the rear end surface 132A. Thereby, in the stirring rod 132, the conveying force of the toner T to the replenishing chamber 105 (see FIG. 7) is increased as compared with the configuration in which the width in the direction intersecting the moving direction of the rear end surface 132A is narrow.

  In other words, the stirring rod 132 has a stirring force for stirring the toner T and a transporting force for transporting the toner T to the replenishing chamber 105 side are enhanced by one member.

  Subsequently, as shown in FIG. 1, in the image forming apparatus 10, the above-described image forming operation (development process, transfer process, fixing process) is performed, and the toner image TZ is fixed on the recording paper P. Here, since the decrease in the fluidity of the toner T is suppressed in the developing device 130, the image forming apparatus 10 secures an amount of toner T necessary for image formation, and an image defect caused by insufficient supply of the toner T. Is suppressed.

  In addition, this invention is not limited to said embodiment.

  The image forming apparatus 10 is not limited to the one having the developing devices 100 and 130 corresponding to the toner T of one color, but may be one in which the developing devices 100 and 130 are provided for a plurality of colors. In this case, the transfer unit is not limited to the transfer roll 28 but may be a transfer device that transfers the toner T of a plurality of colors onto the recording paper P after being superimposed on the intermediate transfer belt.

  The developing devices 100 and 130 may be those in which the restriction block 107 is not provided in the housing 102. Further, the developing device may not be applied with the arrangement setting of the stirring rod 110 shown in FIGS. 4B and 4C, and any one of them may be applied. Also good.

  The wall portion is not limited to the partition wall 102F because it may be a wall for raising the upper surface of the toner T filled in the developing chamber 103 to a certain height position.

  The drive unit 120 is not limited to the one using a crank, and the stirring rods 110 and 132 may be raised to the first position by a cam and the stirring rods 110 and 132 may be dropped by their own weight after the cam has passed. Good. Further, the drive unit 120 may use another motor (drive source) instead of the motor 122 that rotationally drives the developing roll 104, the supply roll 106, and the replenishment paddle 108.

  The stirring rods 110 and 132 are not limited to a circular shape or a triangular shape, and may have an elliptical shape, a semicircular shape, a fan shape, a polygonal shape of a square or more, a V shape, or the like. Moreover, you may use as a stirring bar what the front-end | tip is not thin and the rear-end surface is wide.

10 Image forming apparatus 22 Photosensitive member (an example of an image holding member)
28 Transfer roll (an example of transfer means)
100 Developing Device 102 Housing (Example of Developer Container)
102F Partition wall (an example of a wall)
102H Inner wall surface (an example of a wall surface)
103 Development chamber (example of first chamber)
104 developing roll (an example of a developer holding member)
105 Supply room (example of second room)
106 Supply roll (an example of a supply member)
108 Supply paddle (an example of a conveying member)
110 Stir bar (an example of a moving member)
120 drive unit (an example of drive means)
130 Developing Device 132 Stir Bar (Example of Moving Member)
132A Rear end face K Common tangent T Toner (an example of a one-component developer)
TZ toner image (example of developer image)

Claims (8)

A supply member for supplying a one-component developer of powder to the developer holding member;
A first chamber in which the supply member is rotatably arranged and the one-component developer is accommodated is separated from a wall portion of the first chamber, and the one-component developer supplied to the first chamber is A developer container comprising: a second chamber accommodated;
A first position outside the one-component developer housed in the developer container on the second chamber side of the supply member within a plane orthogonal to the axial direction of the supply member; and the first position And a second member located inside the one-component developer accommodated in the developer container on the supply member side with respect to the wall portion, and a moving member that is reciprocally movable to the second position.
Driving means for driving the moving member to reciprocate the moving member between the first position and the second position;
Have
A developing device that moves the one-component developer from the first chamber side to the second chamber side with respect to the wall portion by movement of the moving member.   The second position is drawn such that, of the common tangent lines of the moving member and the supply member at the first position, the moving member and the supply member are arranged on opposite sides of the common tangent line. The developing device according to claim 1, wherein the developing device is provided on the opposite side of the common tangent to the supply member side.   The developing device according to claim 1, wherein the moving member has a shape that narrows toward a tip when viewed in a moving direction to the second position.   The said moving member has a rear-end surface which spreads in the direction which cross | intersects this moving direction on the back side seeing in the moving direction to the said 2nd position. The developing device according to 1.   The whole moving member passes through the upper end of the one-component developer accommodated in the developer container as it moves between the first position and the second position. The developing device according to any one of the above.   The moving member includes a portion that passes through a height position of an upper end of the wall surface on the first chamber side in the wall portion in accordance with the movement between the first position and the second position. The developing device according to claim 4. The second chamber is provided with a conveying member for conveying the one-component developer in the second chamber to the first chamber,
7. The driving unit moves the moving member from the first position to the second position after the transport member finishes transporting the one-component developer to the first chamber. The developing device according to claim 1. The developing device according to any one of claims 1 to 7, wherein a latent image held by the image carrier is developed with a one-component developer to form a developer image;
Transfer means for transferring the developer image of the image carrier to a recording medium;
An image forming apparatus.