JP2011107643A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve stable detection of density while miniaturizing a developing device. <P>SOLUTION: The developing devices (Gy to Gk) include: developer carriers (R0y to R0k), each of which has a cylindrical body (18) and a magnetic member (17); a developing container (V) supporting each of the developer holders (R0y to R0k) and having a first storage chamber (6) and a second storage chamber (7); a first inflow section (E1) and a second inflow section (E2); a first conveying member (31) for conveying developer in the first storage chamber (6) in a first conveying direction and also supplying the developer to each of the developer holders (R0y to R0k); a second conveying member (41) for conveying the developer in the second storage chamber (7) in a second conveying direction; a density detecting member (51) disposed at the upstream end of each of the developer holders (R0y to R0k) in the first conveying direction; and a density detecting surface (53) disposed while facing the first storage chamber (6) such that the downstream end of the surface in the first conveying direction is disposed further downstream than the upstream end of the magnetic member (17). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  In a conventional electrophotographic image forming apparatus, as a developer for developing a latent image into a visible image, a two-component developer including a toner and a carrier is employed, and the toner is consumed during development. As a result, the toner ratio, so-called toner density, decreases. For the density detection member for detecting the toner density when the developer is replenished based on the toner density, techniques described in the following Patent Documents 1 to 4 are known.

Japanese Patent Application Laid-Open No. 2006-323245 as Patent Document 1 discloses a first stirring screw (32) for supplying toner to the developing roller (31) and a toner on the opposite side of the first stirring screw (32). A second agitating screw (33) for conveying and circulating the first agitating chamber (37) for accommodating the first agitating screw (32) and a second agitating screw (33) for accommodating the first agitating screw (33). A developing device (11b to 14b) having a developing case (34) provided with two stirring chambers (38) is described.
In Patent Document 1, a toner concentration sensor (43) is provided on the flat bottom surface on the second stirring chamber (38) side of the developing case (34) on the side where the toner supply port (42) is provided. A technique for detecting the concentration of toner in the second stirring chamber (34) is described.

Japanese Patent Application Laid-Open No. 2009-2223013 as Patent Document 2 discloses that a first conveying screw (55) for supplying a developer to a developing roller (51) and the first conveying screw (55) rotate in the same direction. A second conveying screw (56) for conveying and circulating the developer to the opposite side of the first conveying screw (55), and a first conveying path having a U-shaped cross section in which the first conveying screw (55) is accommodated ( 53) and a U-shaped cross section that is adjacent to the first transport path (53) and is lower than the first transport path (53) and that accommodates the second transport screw (56). A developing device (5) having a second conveying path (54) of the mold is described.
Patent Document 2 discloses that a second transport path (53) is obliquely below the bottom surface of the first transport path (53) and on the first transport path (53) side of the bottom surface of the second transport path (54). 54) A technique for detecting the toner concentration in the second transport path (54) on the side where the toner supply port (44) is provided by providing a magnetic sensor (57) in the vicinity of the pumping portion at the downstream end in the transport direction. Is described.

In Japanese Patent Application Laid-Open No. 2002-162807 as Patent Document 3, a screw (68) for supplying a developer to a developing sleeve (65) and a screw (68) for conveying and circulating the developer are arranged in a horizontal direction. There is described a developing case (71) having an agitating section (66) separately arranged by a partition plate (69) arranged in parallel and extending vertically.
In Patent Document 3, a toner concentration sensor (71) is provided at the bottom of the agitating portion (66) on the developing sleeve (65) side of the developing case (71) to detect the toner concentration in the agitating portion (66). The technology to do is described.

Japanese Patent Application Laid-Open No. 2009-92762 as Patent Document 4 discloses a first circulation path (A) in which a first stirring and conveying screw (13) for supplying a developer to a developing roller (12) is accommodated, and the first circuit. In the horizontal direction of the circulation path (A), adjacent to the side away from the developing roller (12), a second agitating and conveying screw (14) for conveying and circulating the developer is accommodated, and a toner replenishing port (11b) is provided. A developing tank (11) having a second circulation path (B) is described.
In Patent Document 4, a toner concentration sensor (16) is provided on the bottom surface of the developing tank (11) on the first circulation path (A) side so as to correspond to the downstream end in the transport direction of the first stirring screw (13). A technique for detecting the toner density immediately after development is described.

Japanese Patent Laying-Open No. 2006-323245 (“0017” to “0024”, FIGS. 2 and 3) Japanese Unexamined Patent Application Publication No. 2009-2223013 (“0048” to “0050”, “0059”, FIGS. 3 to 4) Japanese Patent Laid-Open No. 2002-162807 (“0093” to “0097”, FIG. 4) JP 2002-92762 A (“0056” to “0060”, FIG. 1 and FIG. 4)

  An object of the present invention is to enable stable density detection while downsizing a developing device.

In order to solve the technical problem, the developing device of the invention according to claim 1 comprises:
A developer having a rotating cylindrical cylindrical body and a magnet member disposed inside the cylindrical body, and capable of holding the developer on the outer surface of the cylindrical body by the magnetic force of the magnet member Holding body,
A developer container that supports the developer holder and contains developer therein, and is disposed adjacent to the first container chamber and a first container chamber facing the developer holder. A developing container having a second storage chamber;
A first inflow portion that is provided in the developer container and allows the developer to flow from the second storage chamber into the first storage chamber;
A second inflow portion that is provided in the developer container and allows the developer to flow from the first storage chamber into the second storage chamber;
The developer in the first storage chamber is disposed in the first storage chamber and transports the developer in the first storage chamber in a first transport direction from the first inflow portion toward the second inflow portion. A first conveying member to be supplied;
A second transport member that is disposed in the second storage chamber and transports the developer in the second storage chamber in a second transport direction from the second inflow portion toward the first inflow portion;
A density detection member that has a density detection surface and detects the density of the developer, the density detection member disposed corresponding to an upstream end of the developer holder in the first transport direction;
The downstream end in the first transport direction is disposed on the downstream side in the first transport direction with respect to the upstream end in the first transport direction of the magnet member. The concentration detection surface;
It is provided with.

The invention according to claim 2 is the developing device according to claim 1,
A first rotating shaft that extends along the developer holder and is rotatably supported by the developer container; and a developer that is provided on an outer peripheral surface of the first rotating shaft and rotates with the first rotating shaft. A first conveying member having a conveying blade that conveys the first conveying direction in the first conveying direction;
An adsorption magnetic pole having a plurality of magnetic poles for adsorbing developer on the outer surface of the cylindrical body, and a separation magnetic pole for peeling off the developer adsorbed and held on the outer surface of the cylindrical body are formed. The magnet member
From the peeling return position where the developer peeled by the peeling magnetic pole is returned to the first transport space where the developer is transported in the first transport direction by the first transport member, to the detection position where the density detection surface is disposed. Downstream in the first conveying direction moved along the first conveying blade by the phase from the upstream end in the first conveying direction of the magnet member with respect to the phase along the rotation direction of the first rotating shaft. The concentration detection surface arranged on the upstream side in the first transport direction from the position on the side;
It is provided with.

According to a third aspect of the present invention, in the developing device according to the first or second aspect,
A first rotating shaft that extends along the developer holder and is rotatably supported by the developer container; and a developer that is provided on an outer peripheral surface of the first rotating shaft and rotates with the first rotating shaft. A first conveying member having a conveying blade that conveys the developer in the first conveying direction, and a stirring blade that is provided at a position facing the density detection surface of the first rotation shaft and agitates the developer,
It is provided with.

In order to solve the technical problem, an image forming apparatus according to a fourth aspect of the present invention provides:
A rotating image carrier;
A latent image forming apparatus for forming a latent image on the surface of the image carrier;
The developing device according to any one of claims 1 to 3, which develops a latent image on the surface of the image carrier into a visible image;
A transfer device for transferring a visible image on the surface of the image carrier to a medium;
A fixing device for fixing a visible image on the surface of the medium;
It is provided with.

According to the first and fourth aspects of the present invention, it is possible to reduce the size of the developing device in a stable manner as compared with the case where the density detecting member is not disposed corresponding to the upstream end portion of the developer holding member in the first transport direction. Concentration can be detected.
According to the second aspect of the present invention, the concentration detection surface from the upstream end in the first conveyance direction of the magnet member with respect to the phase along the rotation direction of the first rotation shaft from the peeling return position to the detection position. The influence of the developer peeled off by the peeled magnetic pole can be reduced as compared with the case where it is disposed at the downstream position in the first transport direction moved along the first transport blade by the phase or more.
According to the third aspect of the present invention, the concentration detection can be stabilized as compared with the case where the stirring blade is not provided at the position facing the concentration detection surface.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment of the present invention. 3A and 3B are explanatory views of the developing device according to the first embodiment of the present invention. FIG. 3A is a cross-sectional perspective view of a main part in a state where the developing container cover is removed, FIG. 3B is an explanatory view of a supply auger, and FIG. It is explanatory drawing of an auger. 4 is a cross-sectional view of the developing device corresponding to the cross-sectional view taken along the line IV-IV in FIG. 3A. FIG. 5 is an explanatory view of the developing roll and is a partial cross-sectional view of the developing roll. FIG. 6 is a view for explaining the positional relationship among the magnet roll, the supply auger, and the density sensor when mounted on the developing device. FIG. 7 is a view corresponding to FIG. 6, FIG. 7A is an enlarged view of a main part of FIG. 6, and FIG. FIG. 8 is an explanatory diagram of the developer distribution in the first stirring chamber of Example 1, FIG. 8A is a diagram corresponding to FIG. 7A, and FIG. 8B is a diagram of the developer distribution in the first transport direction with respect to the supply auger. It is explanatory drawing. FIG. 9 is an explanatory view of the developer distribution in the first stirring chamber of Example 1, FIG. 9A is a diagram corresponding to the cross-sectional view taken along the line IXA-IXA in FIG. 8A, and FIG. 9B is the line IXB-IXB in FIG. 9C is a diagram corresponding to the IXC-IXC line cross-sectional view in FIG. 8A, FIG. 9D is a diagram corresponding to the IXD-IXD line cross-sectional view in FIG. 8A, and FIG. 9E is IXE-IXE in FIG. It is a figure corresponding to a line sectional view.

Next, examples as specific examples of embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a copying machine U as an example of an image forming apparatus includes an automatic document feeder U1 and an apparatus body U2 that supports the automatic document feeder U1 and has a transparent document reading surface PG at the upper end.
The automatic document feeder U1 includes a document feeding unit TG1 that accommodates a plurality of documents Gi to be copied, and a document feeding position that is fed from the document feeding unit TG1 and passes through a document reading position on the document reading surface PG. A document discharge section TG2 from which the document Gi is discharged.
The apparatus main body U2 includes an operation unit UI through which a user inputs an operation command signal for starting an image forming operation, an exposure optical system A, and the like.

Reflected light from a document conveyed on the document reading surface PG by the automatic document feeder U1 or a document manually placed on the document reading surface PG is passed through the exposure optical system A by the solid-state image sensor CCD. It is converted into electrical signals of red: R, green: G, blue: B.
The information conversion unit IPS converts the RGB electrical signals input from the solid-state imaging device CCD into image information of black: K, yellow: Y, magenta: M, cyan: C, and temporarily stores the image information. The information is output to the latent image forming circuit DL as image information for forming a latent image at a preset time.
When the original image is a single color image, so-called monochrome, image information of only black: K is input to the latent image forming circuit DL.
The latent image forming circuit DL has latent image forming circuits (not shown) for the respective colors Y, M, C, and K, and a latent image forming device driving signal corresponding to input image information is set at a preset time. Output to a latent image writing light irradiation unit (not shown) of each color of the latent image forming apparatus ROS.

Visible image forming devices Uy, Um, Uc, Uk arranged above the latent image forming device ROS are respectively visible images of yellow: Y, magenta: M, cyan: C, and black: K. This is an apparatus for forming a toner image as an example.
The latent image forming lights Ly, Lm, Lc, and Lk are emitted from the respective latent image forming light irradiation units (not shown) of the latent image forming apparatus ROS. The latent image writing lights Ly to Lk are incident on rotating photoreceptors PRy, PRm, PRc, and PRk, respectively, as an example of an image carrier.
The Y-color visible image forming device Uy includes a photoreceptor PRy, a charger CRy, a developing device Gy, and an image carrier cleaning device CLy, and the visible image forming devices Um, Uc, Uk are all. It is configured in the same manner as the Y-color visible image forming device Uy.

FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment of the present invention.
1 and 2, the photoconductors PRy, PRm, PRc, and PRk are charged by their respective chargers CRy, CRm, CRc, and CRk, and then at the image writing positions Q1y, Q1m, Q1c, and Q1k. An electrostatic latent image is formed on the surface of the latent image writing lights Ly to Lk. The electrostatic latent images on the surfaces of the photoconductors PRy, PRm, PRc, and PRk are developed in the developing regions Q2y, Q2m, Q2c, and Q2k as developing roller R0y as an example of a developer holding member of the developing devices Gy, Gm, Gc, and Gk. , R0m, R0c, and R0k are developed into a toner image as an example of a visible image.
The developed toner image is conveyed to primary transfer regions Q3y, Q3m, Q3c, and Q3k that are in contact with an intermediate transfer belt B as an example of an intermediate transfer member. The primary transfer units T1y, T1m, T1c, and T1k disposed on the back side of the intermediate transfer belt B in the primary transfer regions Q3y, Q3m, Q3c, and Q3k are preliminarily supplied from the power supply circuit E controlled by the control unit C. At the set time, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied.

  The toner images on the photoconductors PRy to PRk are primarily transferred to an intermediate transfer belt B as an example of an intermediate transfer body by the primary transfer units T1y, T1m, T1c, and T1k. Residues and deposits on the surface of the photoreceptors PRy, PRm, PRc, and PRk after the primary transfer are cleaned by the photoreceptor cleaners CLy, CLm, CLc, and CLk. The cleaned surfaces of the photoreceptors PRy, PRm, PRc, and PRk are recharged by the chargers CRy, CRm, CRc, and CRk.

  Above the photoconductors PRy to PRk, a belt module BM as an example of an intermediate transfer device is disposed. The belt module BM includes the intermediate transfer belt B, a belt drive roll Rd as an example of an intermediate transfer member drive member, a tension roll Rt as an example of a tension applying member, a walking roll Rw as an example of a meandering prevention member, and a driven It includes an idler roll Rf as an example of a member, a backup roll T2a as an example of a secondary transfer counter member, and the primary transfer units T1y, T1m, T1c, and T1k. The intermediate transfer belt B is rotatably supported by the rolls Rd, Rt, Rw, Rf, and T2a.

A secondary transfer roll T2b as an example of a secondary transfer member is disposed facing the surface of the intermediate transfer belt B in contact with the backup roll T2a. The backup roll T2a and the secondary transfer roll T2b constitute a secondary transfer device T2. Further, a secondary transfer region Q4 is formed by a region where the secondary transfer roll T2b and the intermediate transfer belt B face each other.
The single-color or multi-color toner images transferred on the intermediate transfer belt B by the primary transfer units T1y, T1m, T1c, and T1k in the primary transfer regions Q3y, Q3m, Q3c, and Q3k It is conveyed to the secondary transfer area Q4.
The primary transfer units T1y to T1k, the intermediate transfer belt B, the secondary transfer unit T2, and the like constitute a transfer device T1 + T2 + B of Example 1 that transfers an image formed on the photoconductors PRy to PRk to a medium.

  Below the visible image forming devices Uy to Uk, a pair of left and right guide rails GR as an example of a guide member is provided, and the guide rail GR has a sheet feed as an example of a sheet feeding unit. The trays TR1 to TR3 are supported so as to be able to enter and exit in the front-rear direction. A recording sheet S as an example of a medium accommodated in the paper feed trays TR1 to TR3 is taken out by a pickup roll Rp as an example of a medium take-out member and separated one by one by a separating roll Rs as an example of a medium separating member. The The recording sheet S is transported along a sheet transport path SH, which is an example of a medium transport path, by a plurality of transport rolls Ra, which is an example of a medium transport member, and is disposed upstream of the secondary transfer region Q4 in the sheet transport direction. Is sent to a registration roll Rr as an example of the transport time adjusting member. A sheet conveying device SH + Ra + Rr is configured by the sheet conveying path SH, the sheet conveying roll Ra, the registration roll Rr, and the like.

The registration roll Rr conveys the recording sheet S to the secondary transfer area Q4 in time for the toner image formed on the intermediate transfer belt B to be conveyed to the secondary transfer area Q4. When the recording sheet S passes through the secondary transfer region Q4, the backup roll T2a is grounded, and the secondary transfer unit T2b is supplied with a polarity opposite to the charged polarity of the toner from the power supply circuit E controlled by the control unit C. A secondary transfer voltage is applied. At this time, the toner image on the intermediate transfer belt B is transferred to the recording sheet S by the secondary transfer device T2.
The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLb as an example of an intermediate transfer body cleaner.

The recording sheet S on which the toner image is secondarily transferred has a fixing region Q5 which is a contact region of a heating roll Fh as an example of a heating fixing member of the fixing device F and a pressure roll Fp as an example of a pressure fixing member. And heated and fixed when passing through the fixing region Q5. The heat-fixed recording sheet S is discharged from a discharge roller Rh as an example of a medium discharge member to a discharge tray TRh as an example of a medium discharge unit.
A release agent for improving the releasability of the recording sheet S from the heating roll Fh is applied to the surface of the heating roll Fh by a release agent coating device Fa.

  Above the belt module BM, developer cartridges Ky, Km, Kc, and Kk as an example of developer storage containers that store yellow: Y, magenta: M, cyan: C, and black: K developers are arranged. Has been. Developers stored in the developer cartridges Ky, Km, Kc, Kk are replenished to the developing devices Gy, Gm, Gc, Gk according to the consumption of the developer in the developing devices Gy, Gm, Gc, Gk. Is done. In Example 1, the developer contained in the developing devices Gy to Gk is constituted by a two-component developer including a magnetic carrier and a toner to which an external additive is applied. Then, toner is supplied to the developing devices Gy to Gk from the developer cartridges Ky to Kk.

(Description of developing device)
FIG. 3 is a perspective explanatory view of the developing device according to the first embodiment of the present invention, FIG. 3A is a perspective explanatory view of a main part in a state where the developing container cover is removed and the developing roll is omitted, and FIG. 3B is a perspective view of the supply auger. FIG. 3C is a perspective explanatory view of the stirring auger.
4 is a cross-sectional view of the developing device corresponding to line IV-IV in FIG. 3A.
Next, the developing devices Gy, Gm, Gc, and Gk according to the first embodiment of the present invention will be described. Since the developing devices Gy, Gm, Gc, and Gk of the respective colors are configured in the same manner, the development of the Y color is performed. Only the apparatus Gy will be described in detail, and detailed descriptions of the other color developing apparatuses Gm, Gc, Gk will be omitted.
2 to 4, the developing device Gy arranged to face the photoconductor PRy has a developing container V that stores a two-component developer containing toner and a carrier. The developer container V includes a developer container main body 1, a developer container cover 2 as an example of a lid member for closing the upper portion of the developer container main body 1 as shown in FIG. 4, and a rear of the developer container main body 1 as shown in FIG. 3A. It has the receiving cylinder 3 as an example of the receiving part connected with the end. In FIG. 4, the developing container V of Example 1 has an opening V1 corresponding to the developing region Q2y facing the photoconductor PRy, and the photoconductor PRy side is open.

In FIG. 3A and FIG. 4, inside the developing container V, a developing roll chamber 4 as an example of a holding body containing portion and an example of a first containing chamber are arranged adjacent to the lower side of the developing roll chamber 4. As an example of the first stirring chamber 6 and the second storage chamber, the developing container V is disposed adjacent to the lower right side of the first stirring chamber 6 in order to reduce the size in the horizontal and vertical directions. The second stirring chamber 7 is provided. The lengths of the first stirring chamber 6 and the second stirring chamber 7 in the front-rear direction are longer than the developing roll chamber 4.
In FIG. 3A, a replenishing chamber 3 a is formed inside the receiving cylinder 3 on the rear side of the second stirring chamber 7. The replenishing chamber 3 a is connected to the rear end of the second stirring chamber 7. A developer replenishing port 3b as an example of a new developer receiving portion is formed on the upper surface of the receiving cylinder 3, and the developer from the developer cartridge Ky is replenished.

  3A and 4, a partition wall 8 is formed along the stirring chambers 6 and 7 between the first stirring chamber 6 and the second stirring chamber 7 in the developing container body 1. In FIG. 3A, a rising inflow portion E <b> 1 that connects the first stirring chamber 6 and the second stirring chamber 7 is formed at the front end portion of the partition wall 8 as an example of the first inflow portion. In addition, a descending inflow portion E2 that connects the first stirring chamber 6 and the second stirring chamber 7 is formed at the rear end portion of the partition wall 8 as an example of the second inflow portion. Accordingly, the developers in the respective stirring chambers 6 and 7 are configured to be movable with respect to each other through the inflow portions E1 and E2.

In FIG. 4, the developing roll chamber 4 accommodates a developing roll R0y as an example of a developer holder. In FIG. 3A, the front end of the developing roll R0y is supported by a U-shaped groove-shaped support portion 9a formed on the front end wall 9 of the developing container main body 1, and the rear end of the developing roll R0y is the developing container main body. 1 is supported by a circular hole-shaped support portion 11 a formed on the rear end wall 11.
In FIG. 4, a trimmer housing chamber 4a as an example of a layer thickness regulation housing portion is formed diagonally to the left of the developing roll R0y. The trimmer storage chamber 4a has a trimmer 12 as an example of a layer thickness regulating member that extends along the developing roll R0y and faces the surface of the developing roll R0y and regulates the layer thickness of the developer on the surface of the developing roll R0y. Is housed.

In FIG. 4, the developing roll R0y is rotatably supported on the outer periphery of the magnet roll 13 as an example of a magnet roll 13 as an example of a magnet member fixedly supported by the developing container V and an example of a cylindrical cylindrical body. And a developing sleeve 14 whose surface moves in the same direction as the surface of the photoreceptor PRy in the developing region Q2y.
In FIG. 4, the magnet roll 13 has a support shaft 16 extending in the front-rear direction. A magnet roll body 17 as an example of a magnet member body is fixedly supported on the support shaft 16.
In FIG. 4, the magnet roll body 17 has a developing magnetic pole S1 that is disposed to face the developing region Q2y and causes the developer on the surface of the developing sleeve 14 to stand toward the photoreceptor PRy. Further, the magnet roll body 17 is disposed upstream of the developing magnetic pole S1 in the rotation direction of the developing sleeve 14 and is opposed to the trimmer 12, and the developer on the surface of the developing sleeve 14 is erected to develop the trimmer 12. It has a layer thickness regulating magnetic pole N2 that regulates the layer thickness of the agent.

Further, the magnet roll body 17 is disposed downstream of the developing magnetic pole S1 in the rotation direction of the developing sleeve 14, and generates a magnetic force for holding the developer on the surface of the developing sleeve 14, and as the developing sleeve 14 rotates, It has a conveyance magnetic pole N1 for conveying the held developer. Further, the magnet roll body 17 is arranged on the downstream side in the rotation direction of the developing sleeve 14 with respect to the transport magnetic pole N1, and a pick-off magnetic pole as an example of a peeling magnetic pole for peeling the developer held on the surface of the developing sleeve 14 from the developing sleeve 14. S2. The magnet roll body 17 is disposed between the pick-off magnetic pole S2 and the layer thickness regulating magnetic pole N2, and serves as an example of an attracting magnetic pole that attracts the developer in the first stirring chamber 6 to the outer surface of the developing sleeve 14. A pickup magnetic pole S3 is provided.
The support shaft 16 and the magnet roll body 17 constitute the magnet roll 13 of the first embodiment.

FIG. 5 is an explanatory view of the developing roll and is a partial cross-sectional view of the developing roll.
In FIG. 5, the developing sleeve 14 is rotatably supported on the support shaft 16 of the magnet roll 13. The developing sleeve 14 includes a cylindrical sleeve body 18 in which the magnet roll body 17 is disposed as an example of a cylindrical body body.
In FIG. 5, a sleeve rear end support member 19 as an example of a cylindrical rear end support member is supported at the rear end of the sleeve body 18. The sleeve rear end support member 19 is rotatably supported on the rear end of the support shaft 16 of the magnet roll 13 via a bearing 21. The sleeve rear end support member 19 includes a cylindrical support member main body 19a supported by the bearing 21, and an axial shape formed on the rear portion of the support member main body 19a and extending backward on the support shaft 16. The supported portion 19b.

A sleeve front end support member 22 as an example of a cylindrical front end support member is supported at the front end of the sleeve body 18. The sleeve front end support member 22 is rotatably supported by a support shaft 16 in front of the magnet roll body 17 via a bearing 23. The sleeve front end support member 22 is formed in a cylindrical support member main body 22a supported by the bearing 23, and in a front portion of the support member main body 22a and in a cylindrical shape having a smaller diameter than the support member main body 22a. And supported portion 22b. The sleeve front end support member 22 is supported by the support shaft 16 while passing through the inside thereof, and is supported in a state where the front end portion of the support shaft 16 protrudes forward with respect to the sleeve front end support member 22.
The sleeve main body 18, the sleeve rear end support member 19, the bearing 21, the sleeve front end support member 22, and the bearing 23 constitute the developing sleeve 14 of the first embodiment.

Further, the magnet roll 13 and the developing sleeve 14 constitute a developing roll R0y of Example 1.
In the developing roll R0y, the supported portions 19b and 22b of the supporting members 19 and 22 at both ends of the developing sleeve body 18 are rotatably supported by the supporting portions 11a and 9a of the corresponding end walls 11 and 9 via bearings (not shown). The front end of the support shaft 16 is fixed to the developing container V by a fixing member (not shown) and supported by the developing container V.
Note that the supported portions 19b and 22b at both ends of the developing sleeve main body 18 are abutted against members on the photosensitive member PRy side and hold the interval between the photosensitive member PRy and the developing roll R0y at a predetermined interval (not shown). An abutting member, a so-called tracking roll, is supported. Further, a driven transmission member (not shown), that is, a so-called gear is supported on the supported portion 19b of the sleeve rear end support member 19, and the driving force is transmitted from the apparatus main body U2.
Accordingly, when the driving force is transmitted to the supported portion 19b, the developing sleeve 14 rotates around the magnet roll 13.

FIG. 6 is a view for explaining the positional relationship among the magnet roll, the supply auger, and the density sensor when mounted on the developing device.
7 is a view corresponding to FIG. 6, FIG. 7A is an enlarged view of a main part of FIG. 6, and FIG. 7B is an enlarged view of a main part in a state where a developing sleeve is attached.
3 and 4, a supply auger 31 as an example of a first transport member is disposed in the first stirring chamber 6.
3B, 6, and 7, the supply auger 31 includes a supply auger shaft 32 that extends along the developing roll R <b> 0 y and is rotatably supported by the developing container V as an example of a first rotating shaft. .

3, 6, and 7, a conveying blade 33 is supported on the outer peripheral surface of the supply auger shaft 32.
The conveying blade 33 according to the first embodiment is formed corresponding to the position of the ascending inflow portion E1, is longer than the opening of the ascending inflow portion E1, and is formed in a double spiral shape with a phase shifted by a half circumference. A double conveying section 33a, a main conveying section 33b formed in a spiral shape from the rear end of one spiral of the double conveying section 33a to the descending inflow section E2, and a rear side of the main conveying section 33b. The amount of movement along the direction of the supply auger shaft 32, that is, the so-called pitch, is smaller than the other transport units 33a and 33b and the winding direction is the other transport units 33a and 33b. And a reverse conveying portion 33c formed in a spiral shape different from the above.

3, 6, and 7, a sensor facing paddle 34 as an example of a stirring blade is supported on the outer peripheral surface of the supply auger shaft 32 at a position corresponding to the front end side of the main transport portion 33b. ing. The sensor facing paddle 34 is formed in a plate shape extending in the radial direction from the supply auger shaft 32 and having a shorter length in the axial direction than the pitch of the main transport portion 33b.
In particular, in Example 1, the sensor-facing paddle 34 has a front end connected to the rear surface of the main transport portion 33b, and is formed in a shape extending axially rearward from the rear surface of the main transport portion 33b.
In Example 1, the sensor-facing paddle 34 is disposed corresponding to the front end portion of the magnet roll 13 when mounted on the developing container V.

3, 6, and 7, a supply paddle 36 as an example of a rear agitating blade along the supply auger shaft 32 is provided on the outer peripheral surface of the supply auger shaft 32 on the rear side of the sensor facing paddle 34. Are supported. The supply paddle 36 according to the first embodiment is formed in a plate shape that extends in the radial direction from the supply auger shaft 32 and has a shorter length in the axial direction than the pitch of the main transport portion 33b.
In particular, in the first embodiment, the supply paddle 36 has a rear end connected to the front surface of the main transport portion 33b and is formed in a shape extending axially forward from the front surface of the main transport portion 33b.
The supply auger 31 according to the first embodiment is configured by the supply auger shaft 32, the conveying blade 33, the sensor facing paddle 34, and the supply paddle 36.

In FIG. 3, a stirring auger 41 as an example of a second transport member is disposed in the second stirring chamber 7. The stirring auger 41 includes a stirring auger shaft 42 that extends along the supply auger 31 and is rotatably supported by the developing container V as an example of a second rotating shaft.
In FIG. 3C, the second conveying blade 43 is supported on the outer peripheral surface of the stirring auger shaft 42.
The second conveying blade 43 of the first embodiment includes a replenishing conveyance portion 43a formed in a spiral shape corresponding to the position of the replenishment chamber 3a, and a front side of the replenishment conveyance portion 43a, and the descending inflow portion The second main transport part 43b formed in a spiral shape from E2 to the rising inflow part E1, and the front side of the second main transport part 43b, the pitch is smaller than the other transport parts 43a, 43b, And it has the 2nd reverse conveyance part 43c formed in the spiral shape from which the winding direction differs from the other conveyance parts 43a and 43b.

3C, on the outer peripheral surface of the agitation auger shaft 42, a plurality of collapsing parts 44 projecting radially from the agitation auger shaft 42 are formed between the replenishment conveyance part 43a and the second main conveyance part 43b. Has been.
Further, in FIG. 3C, a plurality of stirring paddles 46 as an example of front stirring blades are supported on the outer peripheral surface of the stirring auger shaft 42 along the stirring auger shaft 42 on the front side of the breaking portion 44. The stirring paddle 46 according to the first embodiment is formed in a plate shape that protrudes in the radial direction from the stirring auger shaft 42 and extends in the axial direction.
The stirring auger 41 of the first embodiment is configured by the stirring auger shaft 42, the second conveying blade 43, the breaking portion 44, and the stirring paddle 46.

A driven transmission member (not shown), a so-called gear, is supported at the rear end of the supply auger shaft 32 of the supply auger 31, and a driving force is transmitted from the apparatus main body U2.
In FIG. 3A, a gear G <b> 11 as an example of a drive transmission member is supported at the front end of the supply auger shaft 32. The gear G11 is engaged with an intermediate gear G12 as an example of an intermediate transmission member rotatably supported at the front end of the developing container body 1. A gear G13 as an example of a driven transmission member supported by the front end of the stirring auger shaft 42 of the stirring auger 41 is engaged with the intermediate gear G12.
Therefore, when the driving force from the apparatus main body U2 is transmitted to the supply auger shaft 32, the supply auger 31 rotates and the stirring auger 41 rotates via the gears G11 to G13.

As a result, the developer replenished to the developer replenishing port 3 b of the receiving cylinder 3 is conveyed from the replenishing chamber 3 a to the second agitating chamber 7 by the second conveying blade 43 of the agitating auger 41. The developer conveyed to the second agitating chamber 7 is conveyed by the second conveying blade 43 while being agitated in the second conveying direction from the descending inflow portion E2 toward the ascending inflow portion E1 through the second agitating chamber 7. Then, the developer transported to the downstream end of the second stirring chamber 7 in the second transport direction is deposited on the downstream end. The developer that has become bulky due to accumulation passes through the rising inflow portion E <b> 1 and flows into the first stirring chamber 6.
The developer that has flowed into the first stirring chamber 6 is supplied and adsorbed to the developing roll R0y while being conveyed by the conveying blade 32 of the supply auger 31 in the first conveying direction from the rising inflow portion E1 toward the descending inflow portion E2. The

The developer remaining without being adsorbed on the developing roll R0y and the developer peeled off from the developing roll R0y and returned to the first stirring chamber 6 are transported by the supply auger 31 and transported to the descending inflow portion E2. When the developer is conveyed to the descending inflow portion E2, the developer passes through the descending inflow portion E2 by the action of gravity and flows into the second stirring chamber 7. The developer that has flowed into the second stirring chamber 7 is also transported in the second transport direction by the stirring auger 41.
Therefore, in Example 1, the developer stored in the developing container V is configured to be able to circulate through the first stirring chamber 6 and the second stirring chamber 7 via the rising inflow portion E1 and the descending inflow portion E2. Yes.
The first stirring chamber 6 and the second stirring chamber 7 constitute the circulation stirring chamber 6 + 7 of the first embodiment.

4, 6, and 7, a density sensor 51, which is an example of a density detection member, is located below the developing roll R <b> 0 y of the developing container V and on the photosensitive body PRy side of the first stirring chamber 6. It is supported by a support portion V2 provided in the container V. The density sensor 51 is disposed corresponding to the upstream end of the developing roll R0y in the first transport direction, that is, the front end.
The concentration sensor 51 according to the first embodiment is supported by the sensor main body 52 as an example of a plate-shaped sensor main body 52 extending in the first transport direction as an example of a concentration detection member main body and as an example of a concentration detection surface. 6 and a circular sensor surface 53 exposed inside.
6 and 7, the rear end of the sensor surface 53 is arranged downstream of the upstream end of the magnet roll body 17 in the first transport direction, that is, behind the front end of the magnet roll body 17. Is done.
The sensor surface 53 is disposed to face the sensor facing paddle 34.

Here, in FIG. 4, a peeling return position Q11 where the developer peeled off by the pick-off magnetic pole S2 is returned to the first transport space where the developer is transported in the first transport direction by the supply auger 31 is set in advance by experiment and measurement. The Accordingly, in FIG. 4, the phase θ along the rotation direction of the supply auger shaft 32 from the peeling return position Q11 to the detection position Q12 where the sensor surface 53 is disposed is set.
At this time, the sensor surface 53 according to the first embodiment has a phase θ from the front end of the magnet roll main body 17 of the magnet roll 13 and is transported to the downstream side in the first transport direction by the supply auger 31. It is arranged on the upstream side in the first transport direction. In FIG. 7, in Example 1, when the pitch of the main conveyance part 33b of the conveyance blade 33 is P, it is rearward from the front end of the magnet roll body 17 by a distance L1 (L1 = P × (θ / 2π)). The rear end of the sensor surface 53 is disposed on the front side of the position.
In the first embodiment, a magnetic permeability type concentration detecting member that detects the magnetic permeability and detects the concentration is used as the concentration sensor 51. Therefore, in Example 1, the density sensor 51 detects the magnetic permeability that changes according to the mixing ratio of the non-magnetic toner and the magnetic carrier, and the ratio of the toner in the developer, so-called developer density. Is detected.

(Operation of Example 1)
In the copying machine U according to the first embodiment having the above-described configuration, in the developing devices Gy to Gk, the developer is conveyed while being stirred in the second stirring chamber 7, passes through the rising inflow portion E <b> 1, and the first stirring chamber 6. Flow into. The developer that has flowed into the first stirring chamber 6 is supplied and adsorbed to the developing rolls R0y to R0k while being conveyed.
The developer adsorbed on the developing rolls R0y to R0k is transported to the developing areas Q2y to Q2k with the layer thickness regulated, and develops the latent images on the surfaces of the photoreceptors PRy to PRk in the developing areas Q2y to Q2k. At this time, the toner in the developer is consumed, and the carrier ratio increases. The developer that has passed through the development regions Q2y to Q2k is peeled off by the pick-off magnetic pole S2 and returned to the first stirring chamber 6.

The developer remaining without being adsorbed on the developing rolls R0y to R0k and the developer peeled off from the developing rolls R0y to R0k and returned to the first agitating chamber 6 is conveyed downstream in the first conveying direction by the supply auger 31. Then, the developer conveyed to the descending inflow portion E2 passes through the descending inflow portion E2 and flows into the second stirring chamber 7. Therefore, the developer in the developing devices Gy to Gk is transported through the second stirring chamber 7 and the first stirring chamber 6 and circulated.
At this time, in the developing devices Gy to Gk of Example 1, the first stirring chamber 6 is downstream of the rising inflow portion E1 in the first transport direction and corresponds to the front end portion of the developing rolls R0y to R0k. The density sensor 51 provided detects the developer density. In accordance with the detection result of the density sensor 51, toner is supplied from the toner cartridges Ky to Kk to the developing devices Gy to Gk, and the developer is stirred and supplied to the developing rolls R0y to R0k in the developing devices Gy to Gk. The

Here, in general, in the developing devices Gy to Gk, the developer is agitated on the downstream side as compared with the upstream side in the transport direction of the developer to loosen the block of toner, and the toner and the carrier are more It is mixed well. Therefore, when detecting the developer concentration, the density detection accuracy is higher when the developer concentration is detected further downstream from the toner replenishment position.
Generally, the concentration sensor 51 is often provided on the second stirring chamber 7 side, but a configuration in which the concentration sensor 51 is further provided on the downstream side of the first stirring chamber 6 is also conceivable.
Here, for example, when the density sensor 51 is provided at the center in the first transport direction on the first stirring chamber 6 side, the density of the developer after the toner is consumed is detected in the development areas Q2y to Q2k. . Therefore, the density of a developer in which a high-density image is developed and a large amount of toner is consumed, and a developer in which a low-density image is developed and a small amount of toner is consumed are detected. As a result, the density of the detection result is greatly affected by the recorded image, and there is a risk that the density of the average developer in the developing devices Gy to Gk is greatly deviated.

In addition, a configuration in which the density sensor 51 is provided in the first stirring chamber 6 apart from the developing rolls R0y to R0k on the upstream side in the first transport direction is also conceivable.
Here, inflowing developer may stay at a position corresponding to the rising inflow portion E1, and when the density sensor 51 is disposed corresponding to the rising inflow portion E1, the concentration of the staying developer is repeatedly detected. In some cases, the reliability of the detection result may be lower than when the density sensor 51 is disposed downstream of the rising inflow portion E1 in the first transport direction.
That is, in the case where the density sensor 51 is provided in the first stirring chamber 6 away from the developing rolls R0y to R0k in the first conveyance direction, a space for arranging the density sensor 51 is required, and the rising flow It is necessary to widen the distance between the part E1 and the developing rolls R0y to R0k in the first transport direction, and the developing devices Gy to Gk are easily increased in size in the first transport direction.

  On the other hand, the density sensor 51 of Example 1 is disposed in the first stirring chamber 6 corresponding to the upstream end in the first transport direction of the developing rolls R0y to R0k, that is, the front end, and the rising inflow With respect to the developer on the downstream side in the first transport direction of the portion E1, the developer concentration at a position where the toner is hardly consumed in the development regions Q2y to Q2k is detected. Therefore, in the first exemplary embodiment, compared to the case where the density sensor 51 is not disposed corresponding to the front ends of the developing rolls R0y to R0k, the developing devices Gy to Gk are downsized and stable density detection is performed.

FIG. 8 is an explanatory diagram of the developer distribution in the first stirring chamber of Example 1, FIG. 8A is a diagram corresponding to FIG. 7A, and FIG. 8B is a diagram of the developer distribution in the first transport direction with respect to the supply auger. It is explanatory drawing.
FIG. 9 is an explanatory view of the developer distribution in the first stirring chamber of Example 1, FIG. 9A is a diagram corresponding to the cross-sectional view taken along the line IXA-IXA in FIG. 8A, and FIG. 9B is the line IXB-IXB in FIG. 9C is a diagram corresponding to the IXC-IXC line cross-sectional view in FIG. 8A, FIG. 9D is a diagram corresponding to the IXD-IXD line cross-sectional view in FIG. 8A, and FIG. 9E is IXE-IXE in FIG. It is a figure corresponding to a line sectional view.
6A to 8A, the density sensor 51 of the first embodiment corresponds to the front end portions of the developing rolls R0y to R0k by a distance L1 (L1 = P × (θ / 2π)) from the front end of the magnet roll body 17. The rear end of the sensor surface 53 is arranged in front of the rear position.

Here, in Example 1, in the first conveyance space of the first agitating chamber 6, the developer is one pitch P of the conveyance blade 33 for each rotation of the supply auger 31 and is downstream in the first conveyance direction. It is conveyed to. That is, the developer is conveyed while being agitated so as to be rotated around the supply auger shaft 32 together with the conveying blades 33 of the supply auger 31.
Therefore, when the developer G1 that may have consumed toner in the development areas Q2y to Q2k is peeled off from the surface of the developing rolls R0y to R0k and returned to the peeling return position Q11, as shown in FIGS. 9A to 9E. The developer G <b> 1 is transported downstream in the first transport direction and transported downstream in the rotational direction of the supply auger shaft 32 according to the rotation of the supply auger 31.

Therefore, the position within the distance L1 from the front end of the magnet roll body 17 to the rear, that is, the position within the distance L1 from the upstream end in the first transport direction where the developer G1 that has passed through the development regions Q2y to Q2k is peeled off. Until FIG. 9A to FIG. 9D, as shown in FIGS. 9A to 9D, the developer G1 is conveyed while being stirred at a position upstream of the detection auger shaft 32 in the rotation direction of the supply auger shaft 32. Developer G1 is difficult to reach.
Therefore, in the density sensor 51 of the first embodiment, the developer G2 remaining in the first stirring chamber 6 without being adsorbed by the developing rolls R0y to R0k reaches the sensor surface 53 at the detection position Q12, and the density of the image is reached. The density of the developer that is not affected by is detected.
Therefore, compared with the case where the density sensor 51 is arranged such that the rear end of the sensor surface 53 is positioned at a distance L1 or more behind the front end of the magnet roll body 17 with respect to the front end portions of the developing rolls R0y to R0k. In the first embodiment, the density of the developer that is not affected by the recorded image is easily detected, and stable density detection is performed.

In the first embodiment, the supply auger 31 is provided with a sensor facing paddle 34 facing the sensor surface 53 of the concentration sensor 51. Here, the sensor-facing paddle 34 according to the first embodiment is formed in parallel with the supply auger shaft 32, and the developer is not subjected to the transport force for transporting in the first transport direction, and is not located at the position where the sensor-facing paddle 34 is disposed. The moving speed in one transport direction is reduced. Therefore, in the first embodiment, the developer in the first stirring chamber 6 is temporarily retained by the sensor facing paddle 34 and is brought to the sensor surface 53 to detect the developer concentration.
Therefore, in the first embodiment, compared to the case where the sensor facing paddle 34 is not provided, the density is detected based on a large amount of developer, and compared to the case where the density is detected based on a small amount of developer. Variations in detection accuracy are reduced and stable density detection is performed.

In particular, in Example 1, the sensor-facing paddle 34 has a front end connected to the rear surface of the main conveyance portion 33b of the conveyance blade 33, and is formed in a shape extending axially rearward from the rear surface of the main conveyance portion 33b. .
Here, as shown in FIG. 8B, the amount of developer between one pitch P of the conveying blades 33 tends to be larger on the upstream side in the first conveying direction than on the downstream side.
Therefore, the sensor-facing paddle 34 according to the first embodiment is disposed at a position where the amount of developer is likely to increase between the pitches P, and the front end is connected to the rear surface of the main conveying portion 33b of the conveying blade 33, Compared to the case where the shape does not extend rearward in the axial direction from the rear surface of the conveyance unit 33b, a larger amount of developer is more likely to be brought to the sensor surface 53, and stable density detection is performed.

In FIG. 7, the rear end of the sensor facing paddle 34 according to the first embodiment is not connected to the front surface of the main transport unit 33 b adjacent to the rear side, and the sensor facing paddle 34 and the main transport unit 33 b in the front-rear direction. A gap 37 is formed between the two.
Here, temporarily, the rear end of the sensor facing paddle 34 is connected to the front surface of the main transport portion 33b of the transport blade 33, and the sensor facing paddle 34 is provided over the entire pitch P of the main transport portion 33b. In this case, the developer is temporarily retained over the entire sensor-facing paddle 34, and the amount of the developer tends to be excessive over the entire pitch P. Accordingly, when the amount of developer increases on the upstream side in the first transport direction relative to the area corresponding to the sensor surface 53 of the density sensor 51, the developing rolls R0y to R0y are arranged on the downstream side in the first transport direction from the position of the sensor surface 53. There is a possibility that the amount of developer supplied to R0k becomes excessive.
In contrast, the sensor-facing paddle 34 according to the first exemplary embodiment is provided with a gap 37 between the conveyance blade 33 and the gap 37 on the downstream side in the first conveyance direction even when the amount of developer increases. The developer flows from. Therefore, as compared with the case where the sensor facing paddle 34 is arranged over the entire pitch P of the main transport portion 33b, the developing devices Gy to Gk of Embodiment 1 have a downstream side in the first transport direction of the sensor facing paddle 34. The amount of the developer supplied to the developing rolls R0y to R0k is excessive and is difficult to achieve.

Note that the supply paddle 36 of the supply auger 31 according to the first embodiment is connected to the front surface of the main transport portion 33b with respect to the sensor facing paddle 34, and extends axially forward from the front surface of the main transport portion 33b. 8A and 8B, the developer is disposed at a position where the amount of the developer is likely to decrease between 1 pitch P.
Here, the supply paddle 36 of the first embodiment is also formed parallel to the supply auger shaft 32, and the developer tends to stay temporarily at the position where the supply paddle 36 is disposed. Therefore, in the first embodiment, the amount of developer in the axial direction varies between pitches compared to the case where the supply paddle 36 is not disposed at a position where the amount of developer tends to decrease between pitches P. In a reduced state, the developer is supplied to the developing rolls R0y to R0k.

Further, the conveying blade 33 of the supply auger 31 of the first embodiment is provided with a double spiral portion 33a corresponding to the rising inflow portion E1, and two sheets each time the supply auger shaft 32 rotates once. Minute vanes carry developer. Therefore, the amount of developer pumped up to the rising inflow portion E1 of the first embodiment is transported to the downstream side in the first transport direction as compared with the case where the developer is transported by one blade, and the upward inflow The retention of the developer in the portion E1 is reduced.
In the first embodiment, the main conveyance unit 33b having one blade is provided instead of the double spiral portion 33a having two blades at the position of the sensor surface 53 of the density sensor 51.
In general, when the blade passes near the sensor surface 53, the amount of the developer is reduced, and the detection result of the density sensor 51 is influenced not only by the developer but also by a blade having a composition different from that of the developer. become. Therefore, the detection result when the blade passes through the sensor surface 53 is inappropriate as the density detection result.

Here, if the double spiral portion 33a is provided at the position where the sensor surface 53 is disposed, the blades pass through the sensor surface 53 twice while the supply auger 31 rotates once, and one of the supply augers 31 Inappropriate density detection is performed twice per rotation.
On the other hand, in the first embodiment, the single spiral main transport unit 33b is provided at the sensor surface arrangement position, and the double spiral part 33a is provided at the sensor surface 53 arrangement position. The time suitable for density detection per rotation of the auger 31 becomes longer, and density detection is easily stabilized.

In FIG. 4, in the developing devices Gy to Gk of the first embodiment, the supply auger 31 is disposed on the lower right side of the developing rolls R0y to R0k, and the stirring auger 41 is disposed on the lower right side of the supply auger 31. In the developing devices Gy to Gk, spaces that are not effectively used, that is, the so-called developing devices Gy to Gk, which are formed below the developing rollers R0y to R0k and outside the developing containers V formed on the photosensitive members PRy to PRk side. The density sensor 51 is disposed in the dead space.
Therefore, in the first embodiment, it is not necessary to secure a space for arranging the density sensor 51 in the developing devices Gy to Gk, and the developing devices Gy to Gk are further compared to the case where the density sensor 51 is not arranged in the dead space. Is miniaturized.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Modification examples (H01) to (H08) of the present invention are exemplified below.
(H01) In the above embodiment, the copying machine U was exemplified as an example of the image forming apparatus. However, the present invention is not limited to this. For example, the copying machine U is configured by a printer, a FAX, or a multifunction machine having a plurality or all of these functions. It is also possible to do.
(H02) In the above embodiment, the copying machine U has exemplified the configuration in which four color developers are used. However, the present invention is not limited to this. For example, a single color image forming apparatus, five or more colors, or three colors or less. The present invention can also be applied to a multicolor image forming apparatus.

(H03) In the above-described embodiment, it is desirable that the density sensor 51 has the rear end of the sensor surface 51 disposed at a position within the distance L1 rearward from the front end of the magnet roll body 17, but the present invention is not limited to this. For example, for the developer adsorbed on the developing rolls R0y to R0k, a region where the toner is consumed in the developing regions Q2y to Q2k is set in advance by experiment and measurement, and the sensor is moved within a distance L1 from the front end of the region to the rear. A configuration in which the rear end of the surface 51 is also possible.
(H04) In the embodiment, the developing devices Gy to Gk are the developing devices Gy to Gk in which the supply auger 31 is disposed on the lower right side of the developing rolls R0y to R0k and the stirring auger 41 is disposed on the lower right side of the supply auger 31. However, the present invention is not limited to this. For example, as in Patent Document 1, a developing device in which a supply auger 31 and a stirring auger 41 are arranged in a horizontal direction, a supply auger 31 is arranged on the right side of the developing rolls R0y to R0k, and a stirring auger 41 below the supply auger 31. It is possible to apply the configuration of the present invention to a conventionally known developing device such as a developing device in which is arranged.

(H05) In the above-described embodiment, it is desirable to provide the sensor facing paddle 34, but a configuration in which the sensor facing paddle 34 is omitted is also possible.
(H06) In the above-described embodiment, the sensor facing paddle 34 is preferably formed parallel to the axial direction. However, the flow of the developer is reduced by making the inclination gentler than the inclination of the blades of the main transport portion 33b. It is also possible to adopt a configuration.
(H07) In the above-described embodiment, the sensor facing paddle 34 is preferably configured such that only the front end is connected to the rear surface of the main conveyance portion 33b of the conveyance blade 33, but is not limited thereto. For example, a configuration is possible in which the rear end is also connected to the conveying blade 33 and the sensor facing paddle 34 is provided over the entire pitch 1 P. Further, it is possible to adopt a configuration in which the sensor facing paddle 34 is provided so that both the front end and the rear end are separated from the conveying blade 33.
(H08) In the above-described embodiment, the supply auger 31 is preferably provided with the double spiral portion 33a and the main transport portion 33b, but it is also possible to omit one and configure only the other. . That is, the main conveyance portion 33b is provided also at a position corresponding to the rising inflow portion E1, and the double spiral portion 33a is also provided at a position corresponding to the developing sleeve 14 on the downstream side in the first conveyance direction of the ascent inflow portion E1. Configuration is also possible.

6 ... first containment chamber,
7 ... Second containment chamber,
17 ... magnet member,
18 ... cylindrical body,
31 ... 1st conveyance member,
32 ... 1st rotating shaft,
33 ... Spiral feather,
34 ... stirring blade,
41 ... second conveying member,
51 ... Concentration detection member,
53. Density detection surface,
E1 ... 1st inflow part,
E2 ... second inflow part,
F: Fixing device,
Gy, Gm, Gc, Gk ... developing device,
N1, N2, S1 ... magnetic poles,
S2: Magnetic pole, peeled magnetic pole,
S3: Magnetic pole, attracting magnetic pole,
PRy, PRm, PRc, PRk ... Image carrier,
Q11 ... peeling back position,
Q12: Detection position,
ROS ... latent image forming device,
R0y, R0m, R0c, R0k ... developer holder,
T1 + T2 + B ... transfer device,
U: Image forming apparatus V: Developer container
θ: Phase.

Claims (4)

A developer having a rotating cylindrical cylindrical body and a magnet member disposed inside the cylindrical body, and capable of holding the developer on the outer surface of the cylindrical body by the magnetic force of the magnet member Holding body,
A developer container that supports the developer holder and contains developer therein, and is disposed adjacent to the first container chamber and a first container chamber facing the developer holder. A developing container having a second storage chamber;
A first inflow portion that is provided in the developer container and allows the developer to flow from the second storage chamber into the first storage chamber;
A second inflow portion that is provided in the developer container and allows the developer to flow from the first storage chamber into the second storage chamber;
The developer in the first storage chamber is disposed in the first storage chamber and transports the developer in the first storage chamber in a first transport direction from the first inflow portion toward the second inflow portion. A first conveying member to be supplied;
A second transport member that is disposed in the second storage chamber and transports the developer in the second storage chamber in a second transport direction from the second inflow portion toward the first inflow portion;
A density detection member that has a density detection surface and detects the density of the developer, the density detection member disposed corresponding to an upstream end of the developer holder in the first transport direction;
The downstream end in the first transport direction is disposed on the downstream side in the first transport direction with respect to the upstream end in the first transport direction of the magnet member. The concentration detection surface;
A developing device comprising: A first rotating shaft that extends along the developer holder and is rotatably supported by the developer container; and a developer that is provided on an outer peripheral surface of the first rotating shaft and rotates with the first rotating shaft. A first conveying member having a conveying blade that conveys the first conveying direction in the first conveying direction;
An adsorption magnetic pole having a plurality of magnetic poles for adsorbing developer on the outer surface of the cylindrical body, and a separation magnetic pole for peeling off the developer adsorbed and held on the outer surface of the cylindrical body are formed. The magnet member
From the peeling return position where the developer peeled by the peeling magnetic pole is returned to the first transport space where the developer is transported in the first transport direction by the first transport member, to the detection position where the density detection surface is disposed. Downstream in the first conveying direction moved along the first conveying blade by the phase from the upstream end in the first conveying direction of the magnet member with respect to the phase along the rotation direction of the first rotating shaft. The concentration detection surface arranged on the upstream side in the first transport direction from the position on the side;
The developing device according to claim 1, further comprising: A first rotating shaft that extends along the developer holder and is rotatably supported by the developer container; and a developer that is provided on an outer peripheral surface of the first rotating shaft and rotates with the first rotating shaft. A first conveying member having a conveying blade that conveys the developer in the first conveying direction, and a stirring blade that is provided at a position facing the density detection surface of the first rotation shaft and agitates the developer,
The developing device according to claim 1, further comprising: A rotating image carrier;
A latent image forming apparatus for forming a latent image on the surface of the image carrier;
The developing device according to any one of claims 1 to 3, which develops a latent image on the surface of the image carrier into a visible image;
A transfer device for transferring a visible image on the surface of the image carrier to a medium;
A fixing device for fixing a visible image on the surface of the medium;
An image forming apparatus comprising:

Images