JP6492480B2 - Developing device, assembly, and image forming apparatus - Google Patents

Description

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

  The developing device of Patent Document 1 supplies the developer from the supply screw to the developing roll while stirring and transporting the developer with the stirring screw and the supply screw. The stirring screw and the supply screw are provided with a plurality of paddles. By making the paddle heights different, the developer conveying speed by the supply screw is lower than the developer conveying speed by the stirring screw.

JP 2012-003193 A

  In the conveyance member that conveys the developer supplied to the holding member to the downstream side in the conveyance direction by the conveyance blade, the paddle extending from the conveyance blade to the upstream side in the conveyance direction is provided. Due to rotation, the developer is less likely to stay. This may reduce the amount of developer supplied to the holding member.

  The present invention relates to a developing device that supplies a developer to a holding member that holds the developer while conveying the developer, compared to a configuration having a plate-like portion extending from the conveying blade toward the upstream side in the conveying direction. The object is to suppress a decrease in the supply amount of the developer.

The developing device according to the first aspect includes an inflow port through which a developer flows in, an outflow port through which the developer flows out, and a wall portion provided from the inflow port to the outflow port, and holds the developer. A housing portion that accommodates the developer supplied to the holding member; a shaft portion that is rotatably supported in the housing portion; and an axial direction of the shaft portion that is formed in the shaft portion and rotates with the shaft portion. A conveying member provided with a conveying blade for conveying the developer as a conveying direction, and at least one of the conveying members is provided on the conveying member so as to face a downstream end of the wall portion in the conveying direction, A plate-like plate-like portion extending toward the downstream side in the transport direction.

In the developing device according to the second aspect , the transport blade is a spiral first blade portion, and the first blade portion and the shaft portion are disposed downstream of the first blade portion in the transport direction of the shaft portion. Is formed with a second spiral blade portion in the opposite direction.

In the developing device according to the third aspect , the plate-like portion is provided in a portion excluding a portion facing the inlet of the transport member.

The assembly according to the fourth aspect, the image carrier, a developing device according to the first embodiment to form a developer image by a developer of the holding member to the image carrier to any one of the third aspect Have.

An image forming apparatus according to a fifth aspect includes the assembly according to the fourth aspect and a transfer unit that transfers the developer image to a recording medium.

Sixth image forming apparatus according to the embodiment, any one of the third aspect the first embodiment and the image carrier is developed with a developer of the holding member to the image carrier to form a developer image And a transfer unit that transfers the developer image to a recording medium.

According to the first aspect of the present invention, in the developing device that supplies the developer to the holding member that holds the developer while conveying the developer, the developer is held as compared with a configuration having a plate-like portion extending from the conveying blade toward the upstream side in the conveying direction. It is possible to suppress a decrease in the amount of developer supplied to the member.

The invention of the second aspect can suppress the shortage of the developer on the downstream side of the holding member, as compared with a configuration that does not have the reverse spiral second blade portion.

The invention of the third aspect can suppress a decrease in the amount of the developer flowing into the accommodating portion as compared with the configuration in which the plate-like portion is located at the position facing the inflow port.

Invention of the fourth aspect can be compared from the first embodiment in the configuration having no developing device according to any one of the third aspect, to prevent the concentration of the developer image becomes thinner.

The invention of the fifth aspect can suppress image defects caused by the density of the developer image becoming lighter than that of the configuration not having the assembly described in the fourth aspect .

A sixth aspect of the invention, as compared with the configuration having no developing device according to the first aspect in any one of the third aspect, suppress image defects due to the concentration of the developer image becomes thinner can do.

1 is an overall configuration diagram of an image forming apparatus according to an exemplary embodiment. It is a block diagram of an image forming unit according to the present embodiment. It is a block diagram of the developing device according to the present embodiment. FIG. 3 is a plan view of the inside of the developing device according to the present embodiment. It is a partial perspective view of the developing device according to the present embodiment. It is explanatory drawing of the developing device which concerns on this embodiment. It is a perspective view of the stirring member which concerns on this embodiment. It is a perspective view of the conveyance member concerning this embodiment. It is a front view of the conveyance member concerning this embodiment. It is explanatory drawing of the developing device which concerns on this embodiment. (A) It is explanatory drawing which shows the conveyance state of the developer by the conveyance member which concerns on this embodiment. (B) It is explanatory drawing which shows the conveyance state of the developer by the conveyance member which concerns on a comparative example.

  An example of the developing device, the assembly, and the image forming apparatus according to the present embodiment will be described.

〔overall structure〕
FIG. 1 shows an image forming apparatus 10 of the present embodiment. As an example, the image forming apparatus 10 includes a transport unit 12 that transports the paper P, four image forming units 20 as an example of an assembly that forms the toner image TZ, and a transfer unit that transfers the toner image TZ to the paper P. 30 and a fixing unit 40 that fixes the toner image TZ to the paper P. The four image forming units 20 have the same configuration except for toners (not shown) of four colors (for example, yellow, cyan, magenta, and black) to be used.

  Further, the image forming apparatus 10 includes a control unit 50 that controls the operation of each unit. The paper P is an example of a recording medium. The toner image TZ is an example of a developer image. Further, the toner image TZ is formed by developing with a developer G (see FIG. 2) by the developing device 100 described later.

  In the following description, the image forming apparatus 10 is viewed from the side where a user (not shown) stands, and the apparatus width direction, the apparatus height direction, and the apparatus depth direction are described as an X direction, a Y direction, and a Z direction. . The X direction, the Y direction, and the Z direction are orthogonal to each other. When it is necessary to distinguish one side and the other side in the X direction, the Y direction, and the Z direction, the image forming apparatus 10 is viewed from the front, the upper side is the Y side, the lower side is the -Y side, and the right side is X side, left side is described as -X side, back side is described as Z side, and front side is described as -Z side.

<Image forming unit>
As shown in FIG. 2, the image forming unit 20 forms a latent image by exposing the photosensitive member 22 as an example of an image carrier, a charging roll 24 that charges the photosensitive member 22, and the charged photosensitive member 22. An exposure unit 26 and a developing device 100 that develops the latent image with toner are provided. Further, the image forming unit 20 has a cleaning blade 28 for cleaning the photosensitive member 22. As described above, the image forming unit 20 is an electrophotographic unit that performs each process of charging, exposure, development, and cleaning. The developing device 100 will be described later.

<Transfer section>
As shown in FIG. 1, the transfer unit 30 includes a transfer belt 32 onto which the toner image TZ is transferred from the photoconductor 22, a drive roll 33 and a driven roll 34 around which the transfer belt 32 is wound, and four primary transfers. A roll 36 and a secondary transfer roll 38 are included. The primary transfer roll 36 primarily transfers the toner image TZ on the photoconductor 22 to the transfer belt 32 due to a potential difference from the grounded photoconductor 22. The secondary transfer roll 38 secondarily transfers the toner image TZ on the transfer belt 32 to the paper P due to a potential difference with the grounded drive roll 33.

[Main part configuration]
Next, the developing device 100 will be described.

  As illustrated in FIG. 3, the developing device 100 includes a housing 102, a developing roll 104 as an example of a holding member, a conveying member 106, and a stirring member 108. Further, the developing device 100 includes a columnar layer regulating member 111 that regulates the thickness of the layer of the developer G (see FIG. 2) held on the outer peripheral surface of the developing roll 104. In FIG. 3, in order to make each member easier to see, cross-sectional hatching of some members is omitted. The layer regulating member 111 is a columnar member having the Z direction as an axial direction, and is made of stainless steel as an example.

  As an example, the developer G includes a toner that is negatively charged and a carrier that is magnetic and positively charged, and further includes an additive. Illustration of toner and carrier is omitted.

<Housing>
As shown in FIG. 4, the housing 102 has a longitudinal direction in the Z direction. As shown in FIG. 3, the housing 102 is disposed so as to be inclined in a direction intersecting the XZ plane. For this reason, the short direction of the housing 102 is described as the A direction, the opening direction perpendicular to the Z direction and the A direction is described as the B direction, and is distinguished from the X and Y directions. When it is necessary to distinguish between the one side and the other side in the A direction and the B direction, when the housing 102 is viewed in the Z direction, the side on which the conveying member 106 is arranged is the A side, and the side on which the stirring member 108 is arranged Is described as -A side, the opening side as B side, and the bottom side as -B side.

  As shown in FIG. 3, the housing 102 is an example of a bottom wall 102 </ b> A that is curved at two locations so as to protrude toward the −B side when viewed in the Z direction, and a wall portion that stands at the center of the bottom wall 102 </ b> A. Partition wall 102B. Furthermore, the housing 102 has a side wall 102C that stands in the B direction at the edge of the bottom wall 102A on the Z side, -Z side, A side, and -A side. The housing 102 accommodates the developer G inside.

  As shown in FIG. 4, a first stirring chamber 112 and a second stirring chamber 114 are formed inside the housing 102 by being partitioned by a partition wall 102 </ b> B. The 1st stirring chamber 112 is an example of an accommodating part, and is arrange | positioned at the A side. The second stirring chamber 114 is arranged on the −A side of the first stirring chamber 112. Further, the bottom surface of the first stirring chamber 112 is, for example, on the Y side (higher position) than the bottom surface of the second stirring chamber 114 because the housing 102 is inclined with respect to the XZ plane (see FIG. 1). Is arranged).

  Further, the housing 102 is provided with a developing chamber 116 in which the developing roll 104 is accommodated on the B side with respect to the first stirring chamber 112. The first stirring chamber 112 and the developing chamber 116 are integral with each other without a partition member.

  As shown in FIGS. 4 and 5, a replenishment section 120 for replenishing toner from a toner cartridge (not shown) is provided on the Z side and the −A side of the housing 102. As shown in FIG. 6, the supply unit 120 has a hollow supply chamber 122. The inside of the replenishing chamber 122 is connected to the inside of the second stirring chamber 114. FIG. 6 schematically shows the developing device 100.

  As shown in FIGS. 4, 5, and 6, the first stirring chamber 112 and the second stirring chamber 114 are opened in the A direction on the −Z side with respect to the −Z side end of the partition wall 102 </ b> B. A connecting inlet 118 is formed. Further, an outlet 119 that opens in the A direction and connects the first stirring chamber 112 and the second stirring chamber 114 is formed on the Z side with respect to the Z side end of the partition wall 102B. That is, the partition wall 102B is formed from the inlet 118 to the outlet 119.

  In the housing 102, the inflow port 118 and the outflow port 119 are formed, so that the developer G (see FIG. 3) can circulate in the first stirring chamber 112 and the second stirring chamber 114. . In the first stirring chamber 112, the direction in which the developer G is transported from the −Z side to the Z side by the transport member 106 is an example of the transport direction. For this reason, in the following description, the conveyance direction is referred to as a + Z direction. In the second stirring chamber 114, the direction in which the developer G is conveyed by the stirring member 108 is opposite to the + Z direction. For this reason, the direction in which the developer G is conveyed in the second stirring chamber 114 is referred to as the −Z direction and is distinguished from the + Z direction.

  In the first stirring chamber 112, a conveying member 106 is rotatably provided with the Z direction as an axial direction. In the second stirring chamber 114, a stirring member 108 is rotatably provided with the Z direction as an axial direction. The developer G (see FIG. 3) accommodated in the housing 102 circulates in the first stirring chamber 112 and the second stirring chamber 114 by the rotation of the conveying member 106 and the stirring member 108. Further, the developer G in the first stirring chamber 112 is supplied to the developing roll 104 (see FIG. 3).

<Development roll>
As shown in FIG. 3, the developing roll 104 has a magnet roll 104A fixed with the Z direction as an axial direction, and a developing sleeve 104B supported so as to be rotatable concentrically with the magnet roll 104A outside the magnet roll 104A. .

  The magnet roll 104A is provided with a plurality of magnetic poles, which will be described later, along the circumferential direction, and generates a magnetic force that attracts or retracts the developer G. Specifically, when the magnet roll 104A is viewed in the Z direction, the pick-up pole S2, the layer forming pole N1, the developing pole S1, the transport pole N2, and the pick-off pole S3 are arranged along the rotational direction from the side closer to the transport member 106. Is provided. A solid line M in FIG. 3 represents the magnetic flux density distribution of the magnet roll 104A.

  The pickup pole S2 attracts the developer G, and the layer forming pole N1 is disposed to face the layer regulating member 111 to regulate the layer thickness of the developer G. The development pole S1 is arranged to face the photoconductor 22 (see FIG. 2), and makes the carrier in the developer G spike. The transport pole N2 holds the developed developer G on the outer circumferential surface of the developing sleeve 104B, and the pickoff pole S3 peels the developer G from the outer circumferential surface of the developing sleeve 104B.

  The developing sleeve 104B rotates in the same direction as the rotation direction of the photoconductor 22 at a position (development region) facing the photoconductor 22 (see FIG. 2). The developing sleeve 104B holds the developer G on the outer peripheral surface, and develops the electrostatic latent image on the photoreceptor 22 with toner to form a toner image TZ (see FIG. 1). In FIG. 6, the use area K of the developer G is indicated by a two-dot chain line. The use area K is an area where the developer G is held on the developing roll 104 and represents an area of the developer G used when developing the latent image on the photoreceptor 22.

<Stirring member>
As shown in FIG. 7, the stirring member 108 includes rotating shafts 108A and 108B integrated with the Z direction as an axial direction, and spiral blade portions 109A and 109B formed on the outer periphery of the rotating shafts 108A and 108B. Have The rotating shaft 108A has a larger diameter than the rotating shaft 108B. The blade portion 109A has a larger diameter than the blade portion 109B and is formed on the outer periphery of the rotating shaft 108A. The blade portion 109B is formed on the outer periphery of the rotation shaft 108B.

  The stirring member 108 is formed with a plate-like paddle 109C that protrudes radially from the outer peripheral surface of the rotating shaft 108A and extends from the blade portion 109A toward the −Z side. As an example, two paddles 109C are arranged for each pitch in the Z direction of the blade portion 109A. The two paddles 109C are arranged so as to be shifted by 180 [°] in the circumferential direction of the rotating shaft 108A.

  As shown in FIG. 6, the rotation shaft 108 </ b> A and the blade portion 109 </ b> A are rotatably provided in the second stirring chamber 114. The rotation shaft 108B and the blade portion 109B are rotatably provided in the supply chamber 122. The stirring member 108 rotates and conveys the developer G from the Z side to the −Z side while stirring. The developer G conveyed to the −Z side by the stirring member 108 flows into the first stirring chamber 112 through the inflow port 118. In FIGS. 6 and 10, the number of intervals (pitch) of the blade portions 109A in the Z direction is smaller than the number shown in FIG.

<Conveying member>
As shown in FIGS. 8 and 9, the conveying member 106 includes a shaft portion 106A whose axial direction is the Z direction, and spiral first blade portions 106B and second blade portions 106C formed on the outer periphery of the shaft portion 106A. And having. The first blade portion 106B is an example of a conveying blade. Further, the transport member 106 is provided with a first paddle 107A, a second paddle 107B, and a third paddle 107C as an example of a plate-like portion.

(Shaft)
As shown in FIG. 8, the shaft portion 106A is formed in a columnar shape having the Z direction as the axial direction. As shown in FIG. 6, both ends in the Z direction of the shaft portion 106 </ b> A are rotatably supported by the Z-side and −Z-side side walls 102 </ b> C of the housing 102. A portion facing the inflow port 118 at the −Z side end of the shaft portion 106A is defined as a facing portion 106D. Further, a portion facing the outflow port 119 at the end on the Z side of the shaft portion 106A is defined as a facing portion 106E.

(First blade part)
As shown in FIG. 9, the first blade portion 106B is spirally formed on the shaft portion 106A so as to transport the developer G (see FIG. 6) from the −Z side to the Z side as the shaft portion 106A rotates. Is formed. The interval (1 pitch interval) in the Z direction of the first blade portion 106B is L.

  As shown in FIG. 6, the first blade portion 106B is disposed to face the range from the inlet 118 of the housing 102 to the Z-side end of the partition wall 102B. In addition, the 1st blade | wing part 106B is not arrange | positioned in the site | part facing the outflow port 119 in 106 A of axial parts. Further, the first blade portion 106B is disposed at a position facing the developing roll 104 (use area K) of the shaft portion 106A.

(Second blade)
As shown in FIG. 9, the second blade portion 106C is formed downstream of the first blade portion 106B in the + Z direction of the shaft portion 106A. Further, the second blade portion 106C is formed in a spiral shape opposite to the first blade portion 106B, and the developer G moves from the Z side to the −Z side as the shaft portion 106A rotates (see FIG. 6). Is supposed to be transported. Furthermore, the second blade portion 106 </ b> C shown in FIG. 6 faces the outflow port 119 and is arranged at the end on the Z side in the first stirring chamber 112.

(1st paddle)
As shown in FIGS. 8 and 9, the first paddle 107A is a plate-like portion that protrudes radially outward from the shaft portion 106A and extends toward the downstream side in the + Z direction from the first blade portion 106B. Specifically, the first paddle 107A is formed in a rectangular plate shape in which the circumferential direction of the shaft portion 106A is the thickness direction, the radial direction of the shaft portion 106A is the height direction, and the Z direction is the width direction. Further, as an example, two first paddles 107A are arranged for each pitch of the first blade portions 106B. The two first paddles 107A are arranged so as to be shifted by 180 [°] in the circumferential direction of the shaft portion 106A.

  For example, the height of the first paddle 107A from the outer peripheral surface of the shaft portion 106A is aligned with the height of the first blade portion 106B from the outer peripheral surface of the shaft portion 106A. Further, the width of the first paddle 107A in the Z direction is, for example, about ¼ of the interval L of one pitch in the first blade portion 106B.

  As shown in FIG. 6, as an example, a plurality of first paddles 107A are provided so that at least one of them faces the downstream end of the partition wall 102B in the + Z direction. Further, as an example, the first paddle 107A is provided in a portion excluding the facing portions 106D and 106E in the shaft portion 106A.

(Second paddle)
As shown in FIGS. 8 and 9, the second paddle 107B is a plate-like portion that protrudes radially outward from the shaft portion 106A and extends toward the upstream side in the + Z direction from the first blade portion 106B. Specifically, the second paddle 107B is formed in a rectangular plate shape in which the circumferential direction of the shaft portion 106A is the thickness direction, the radial direction of the shaft portion 106A is the height direction, and the Z direction is the bottom direction. In addition, as an example, two second paddles 107B are disposed with a 180 ° shift in the circumferential direction of the shaft portion 106A for each pitch of the first blade portions 106B.

  As an example, the height of the second paddle 107B from the outer peripheral surface of the shaft portion 106A is aligned with the height of the first blade portion 106B from the outer peripheral surface of the shaft portion 106A. Further, the length of the second paddle 107B in the Z direction is, for example, about ¼ of the interval L of one pitch in the first blade portion 106B. Further, the first paddle 107A and the second paddle 107B are arranged on a straight line with an interval in the Z direction at one pitch of the first blade portion 106B.

(3rd paddle)
As shown in FIGS. 8 and 9, the third paddle 107C is a plate-like portion that protrudes radially outward from the shaft portion 106A and extends in the Z direction at the center of one pitch of the first blade portion 106B. is there. Specifically, the third paddle 107C is formed in a rectangular plate shape in which the circumferential direction of the shaft portion 106A is the thickness direction, the radial direction of the shaft portion 106A is the short side direction, and the Z direction is the long side direction.

  As shown in FIG. 3, as an example, two third paddles 107C are disposed with a 180 [deg.] Shift in the circumferential direction of the shaft portion 106A for each pitch of the first blade portion 106B. Further, the third paddle 107C is disposed with a 90 ° shift in the circumferential direction of the shaft portion 106A with respect to the first paddle 107A and the second paddle 107B. For example, the height of the third paddle 107C from the outer peripheral surface of the shaft portion 106A is aligned with the height of the first blade portion 106B from the outer peripheral surface of the shaft portion 106A.

  As shown in FIG. 9, the length of the third paddle 107C in the Z direction is, for example, about １ ／ of the interval L of one pitch in the first blade portion 106B.

  As shown in FIG. 6, the developer G transported to the Z side by the transport member 106 flows out into the second stirring chamber 114 through the outlet 119. Although the length of one pitch of the first blade portion 106B of the conveying member 106 and the length of one pitch of the blade portion 109A of the stirring member 108 are approximately the same, the conveying member 106 and the stirring member 108 are The number of each paddle provided is different. For this reason, the conveyance speed [g / m] of the developer G is lower in the conveyance member 106 than in the stirring member 108. 6 and 10, the number of intervals (pitch) of the first blade portions 106B in the Z direction is shown to be smaller than the number shown in FIGS.

[Comparative example]
Next, the developing device 200 of the comparative example will be described.

  A developing device 200 of a comparative example shown in FIG. 11B has a configuration in which a conveying member 202 is provided in place of the conveying member 106 (see FIG. 3) in the developing device 100 (see FIG. 3) of the present embodiment. Yes. The conveying member 202 has a configuration in which the first paddle 107A, the third paddle 107C, and the second blade portion 106C (see FIG. 8) are removed from the conveying member 106 (see FIG. 8) of the present embodiment, and the second paddle 107B is included. It has become. In the developing device 200 of the comparative example, the developer G circulates in the first stirring chamber 112 and the second stirring chamber 114 (see FIG. 6) by rotating the conveying member 202 and the stirring member 108 (see FIG. 6). Is done.

  In the developing device 200 of the comparative example, when the distribution of the developer G is observed for one pitch of the first blade portion 106B, the amount of the developer G is smaller in the downstream portion in the + Z direction than in the upstream portion. Easy to be. This is because the upstream developer G at one pitch is conveyed downstream by the first blade portion 106B, whereas the downstream developer G at one pitch is conveyed downstream by the first blade portion 106B. Because it is difficult. As described above, in the developing device 200 of the comparative example, there are a portion where the amount of the developer G is large and a portion where the amount of the developer G is small for each pitch of the first blade portion 106B, and the developer surface G2 of the developer G around the conveying member 202. However, it becomes wavy in the + Z direction.

  Here, in the developing device 200 of the comparative example, when the conveying member 202 conveys the developer G in the + Z direction, the amount of the developer G is larger in the upstream portion within one pitch than in the downstream portion. There is no means for retaining the developer G in the upstream portion of the pitch. Further, the second paddle 107B is provided in the downstream portion within one pitch (upstream with respect to the first blade portion 106B). However, the developer G in the downstream portion in one pitch is larger than that in the upstream portion. The amount of is small. Thereby, in the developing device 200 of the comparative example, the retention amount of the developer G in the first stirring chamber 112 is small. For this reason, in the developing device 200 of the comparative example, the supply amount of the developer G supplied to the developing roll 104 (see FIG. 2) in the use region K (see FIG. 6) is steadily compared with the target supply amount. Less.

[Action]
Next, the operation of this embodiment will be described.

<Developer circulation>
As shown in FIG. 10, when the transport member 106 and the stirring member 108 are rotated by a motor (not shown), the developer G in the second stirring chamber 114 is transported in the −Z direction by the stirring member 108. At this time, the toner in the developer G and the carrier (not shown) are agitated. Then, the developer G that has reached the −Z side end in the second stirring chamber 114 flows into the first stirring chamber 112 through the inlet 118.

  The developer G that has flowed into the first stirring chamber 112 is transported in the + Z direction by the transport member 106. At this time, the developer G is conveyed to the use area K while the toner and a carrier (not shown) are agitated. In the use area K, a part of the developer G being conveyed is supplied to the developing roll 104 and held on the outer peripheral surface of the developing roll 104 by a magnetic force. Further, the developer G that has not been held by the developing roll 104 reaches the Z-side end portion in the first stirring chamber 112, and flows out into the second stirring chamber 114 through the outflow port 119. In this way, the developer G is circulated in the first stirring chamber 112 and the second stirring chamber 114.

  When a decrease in toner concentration in the developer G is detected by using a toner sensor (not shown), the toner is supplied from the toner cartridge (not shown) into the supply chamber 122. The replenished toner is replenished from the replenishing chamber 122 into the second stirring chamber 114 by the rotation of the rotating shaft 108B and the blade portion 109B. Then, the toner is agitated with the carrier in the developer G by the rotation of the rotating shaft 108A and the blade portion 109A. In this way, the toner concentration in the developer G is maintained.

<Amount of developer in the use area>
As shown in FIG. 11A, in the developing device 100 of the present embodiment, when the transport member 106 rotates, the developer G comes into contact with the surface 106F on the downstream side in the + Z direction of the first blade portion 106B, and + Z Conveyed in the direction. That is, when viewed at one pitch, the upstream developer G is mainly conveyed downstream in the + Z direction.

  Here, a part of the developer G present in the upstream portion within one pitch receives a force F in the circumferential direction of the shaft portion 106A due to contact with the rotating first paddle 107A. As a result, a part of the developer G existing in the upstream portion within one pitch temporarily stays around the shaft portion 106A. As described above, in the developing device 100, the force F is applied to the developer G in the upstream portion within one pitch that is mainly conveyed by the first paddle 107A to be retained. For this reason, in the developing device 100, the retention amount of the developer G in the first stirring chamber 112 is larger than that in the developing device 200 of the comparative example (see FIG. 11B). As a result, as shown in FIG. 10, the amount of the developer G staying in the use area K is increased as compared with the comparative example described above, and the supply amount of the developer G to the developing roll 104 is decreased. It is suppressed.

  As shown in FIG. 10, in the developing device 100, a first paddle 107A is formed from a portion facing the Z-side end of the partition wall 102B to a portion facing the −Z-side end of the partition wall 102B. Therefore, the developer G stays in each part from the Z side end to the −Z side end of the use region K. As a result, it is possible to prevent the developer G from being biased in a part of the developing roll 104 in the + Z direction.

  As shown in FIG. 11A, in the developing device 100, as in the comparative example described above, there are a portion where the amount of the developer G is large and a portion where the amount of the developer G is small within one pitch of the first blade portion 106B. The developer surface G1 of the developer G around the transport member 106 may be wavy in the + Z direction.

  Here, in the developing device 100, a part of the developer G transported in the + Z direction exerts a force F in the circumferential direction by contact with not only the first paddle 107A but also the second paddle 107B and the third paddle 107C. Receive and stay. For this reason, in the developing device 100, the amount of the developer G staying at the central portion and the downstream portion within one pitch is increased as compared with the comparative example described above. That is, in the developing device 100, the difference between the height of the developer surface of the developer G in the upstream portion within one pitch and the height of the developer surface of the developer G in the downstream portion within one pitch is the comparison described above. Since it becomes smaller than the example, the deviation of the stay of the developer G in the + Z direction is suppressed.

  Furthermore, as shown in FIG. 10, in the developing device 100, the second blade portion 106C formed at the downstream end portion in the + Z direction of the shaft portion 106A has a spiral shape opposite to the first blade portion 106B. Therefore, a part of the developer G conveyed in the + Z direction is returned to the −Z direction. Accordingly, even when the amount of the developer G existing on the downstream side in the + Z direction is small when the conveying member 106 starts to rotate, the developer G stays and the amount of the developer G increases. Insufficient amount of the developer G supplied to the end portion 104 is suppressed.

  In addition, as shown in FIG. 10, in the developing device 100, the first paddle 107A, the second paddle 107B, and the third paddle 107C (see FIG. 9) are excluded except the portion facing the inlet 118 of the shaft portion 106A. It is provided at the site. For this reason, the circumferential force F by the first paddle 107A, the second paddle 107B, and the third paddle 107C does not act on the developer G flowing into the first stirring chamber 112 through the inlet 118. . That is, the force to push back the developer G that is about to flow into the first stirring chamber 112 to the second stirring chamber 114 does not act. Thereby, in the developing device 100, the amount of the developer G flowing into the first stirring chamber 112 is suppressed from decreasing.

  In the image forming unit 20 shown in FIG. 2, the supply amount of the developer G to the developing roll 104 is suppressed from being constantly insufficient. Thereby, in the image forming unit 20, the density of the developer image becomes light due to an insufficient amount of the developer G when developing the latent image on the photoconductor 22, as compared with the configuration without the developing device 100. Is suppressed.

  In the image forming apparatus 10 shown in FIG. 1, since the density of the developer image is suppressed to be lower than that in the configuration without the image forming unit 20, the density of the developer image is reduced. Image defects (for example, insufficient image density) are suppressed.

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

  It is sufficient that at least one first paddle 107A is provided at a position facing the Z side end of the partition wall 102B in the first stirring chamber 112. That is, the number of the first paddles 107A may be one, or may be two or more including the number shown in the present embodiment. Further, the shape of the first paddle 107A is not limited to a rectangular shape, and may be another polygonal shape. Furthermore, the first paddle 107 </ b> A is not limited to a linear shape along the Z direction when viewed in the radial direction of the conveying member 106, and may have a curved surface.

  In addition, the first paddle 107 </ b> A has an inlet 118 in a configuration in which the return amount of the developer G from the inlet 118 to the second stirring chamber 114 hardly affects the supply amount of the developer G to the developing roll 104. It may be provided at a position facing the surface.

  The second blade portion 106C may not be formed in a configuration in which the supply amount of the developer G to the developing roll 104 by the first paddle 107A is the target amount.

  The photosensitive member 22 and the developing device 100 are not limited to an assembly like the image forming unit 20, and may be independent elements (single items). Further, the image forming apparatus 10 is not limited to the one having the image forming unit 20, and the photosensitive member 22 and the developing device 100 may be independent.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20 Image forming unit (an example of assembly)
22 photoconductor (an example of an image carrier)
30 Transfer section 100 Developing device 102B Partition wall (an example of a wall section)
104 Developing roll (an example of a holding member)
106 conveying member 106A shaft portion 106B first blade portion (an example of a conveying blade)
106C 2nd blade | wing part 107A 1st paddle (an example of plate-shaped part)
112 1st stirring chamber (an example of an accommodating part)
118 Inlet 119 Outlet G Developer TZ Toner Image (Example of Developer Image)

Claims (7)

A developer supplied to a holding member that holds the developer, comprising: an inlet into which the developer flows; an outlet through which the developer flows out; and a wall portion provided from the inlet to the outlet. An accommodating part for accommodating;
A shaft portion that is rotatably supported in the housing portion, and a spiral first blade portion that is formed on the shaft portion and conveys the developer with the axial direction of the shaft portion as a transport direction in accordance with the rotation of the shaft portion And a conveying member comprising:
A spiral second blade portion formed on the downstream side of the first blade portion in the transport direction of the shaft portion and opposite to the first blade portion;
At least one of the walls is provided on the conveying member so as to face the downstream end in the conveying direction of the wall, and is further provided on a portion excluding a portion facing the inlet of the conveying member . A plate-like plate-shaped portion extending from the blade portion toward the downstream side in the transport direction, the first paddle extending from the first blade portion toward the downstream side in the transport direction, and the transport from the first blade portion. The plate having a second paddle extending upstream in the direction, wherein the first paddle and the second paddle are spaced apart in the axial direction at one pitch of the first blade portion. and Jo part,
A developing device. The plate-like portion protrudes at the center of the first pitch of the first blade portion, and is disposed at a position shifted by 90 ° in the circumferential direction of the shaft portion with respect to the first paddle and the second paddle. the developing device according to claim 1 having a. Two sets of the first paddle and the second paddle are disposed within the one pitch and are shifted by 180 ° in the circumferential direction of the shaft portion.
The first paddle, the third paddle, and the second paddle, which are disposed 90 ° apart from the upstream side in the rotation direction of the transport member within the one pitch, are disposed at the same position in the axial direction. the developing device according to claim 2 which are. A first agitation chamber as the accommodating portion that is long in the apparatus depth direction, and a second agitation chamber that is partitioned from the first agitation chamber by the wall portion and is long in the apparatus depth direction;
The inlet and the outlet connect the first stirring chamber and the second stirring chamber,
Device in the height direction, the bottom surface of the first stirring chamber, a developing device according to any one of claims 1 to 3, which is arranged at a position higher than the bottom of the second stirring chamber. An image carrier,
The developing device according to any one of claims 1 to 4, wherein a developer image by a developer of the holding member is formed on the image holder.
An assembly . An assembly according to claim 5;
A transfer section for transferring the developer image to a recording medium;
An image forming apparatus . An image carrier,
The developing device according to any one of claims 1 to 4, wherein a developer image by a developer of the holding member is formed on the image holder.
A transfer section for transferring the developer image to a recording medium;
An image forming apparatus .

Images