JP4513854B2 - Developing device and image forming apparatus - Google Patents

Description

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

As techniques related to conventional electrophotographic image forming apparatuses, techniques described in Patent Documents 1 to 3 below are known.
Japanese Patent Application Laid-Open No. 2005-37553 as Patent Document 1 discloses that in the developing region where the developing roller (41) and the photosensitive drum (1) face each other, the opening edge (46a) of the developing casing (46) and the photosensitive member. A developing device (4) is described in which a first inlet seal (10a) is disposed as a developer scattering prevention member that closes the gap with the surface of the drum (1). In the technique described in Patent Document 1, in addition to the first inlet seal (10a), the shape is formed along the surface of the developing roller (41), and the tip of the first inlet seal (10a) is upstream of the developing region. A second inlet seal (10b) is provided as a toner reservoir prevention member for preventing the occurrence of toner reservoir that contacts the tip and adheres to the surface of the first inlet seal (10a). Furthermore, in the technique described in Patent Document 1, the second inlet seal (10b) is used until the developer in the form of the developing roller (41) that has passed through the area facing the doctor blade (44) is conveyed to the developing area. The developer is rubbed against the surface of the second inlet seal (10b) by the rotation of the developing roller (41), so that the developer is rubbed against the surface of the second inlet seal (10b). (10b) The developer attached to the surface is collected by the developing roll.

  Japanese Patent Application Laid-Open No. 2000-56566 as Patent Document 2 discloses a film-like film in order to prevent floating toner from leaking outside the apparatus at the opening (22) of the housing (20) of the developing device (7). A technique is described in which a sealing member (60) is provided and a film-like shielding member (62) for preventing toner from adhering to the inner surface of the sealing member (60) is provided. In the technique described in Patent Document 2, the shielding member (62) is disposed on the developing roll (23) from the developer amount regulating member (25) corresponding to the layer thickness regulating member to the contact position with the belt-like photoreceptor (5). It arrange | positions so that it may curve with the surface and substantially constant distance, and it arrange | positions so that a front-end | tip may contact the inner surface of a sealing member (60). In the shielding member (62), the developer that has passed through the developer amount regulating member (25) becomes a spiked magnetic brush, and the surface of the shielding member (62) is rubbed with the magnetic brush. Therefore, it is possible to directly prevent the floating toner from adhering and accumulating on the sealing member (60) by the shielding member (62), and it is also possible to prevent the floating toner from adhering to the shielding member (62) by the magnetic brush. The

  Japanese Patent Laid-Open No. 2001-66887 as Patent Document 3 is provided with a seal member (4) in contact with the photoreceptor (1) on the frame (2) of the developing device to prevent scattering and leakage of the developer. At the same time, a resin member (5) for allowing the developer brush formed by the developer formed on the surface of the developing roller (3) to fill the gap between the inner side of the frame (2) and the developing roller (3) or the like. A technique is described in which a flexible elastic member (6) is arranged to prevent the developer from adhering to and accumulating on the inner surface of the frame (2). Further, in Patent Document 3, after the seal-like member (5) is arranged, the elastic foam member (6) is arranged at the free end portion of the seal-like member (5), and the developing brush (8) It is described that the surface of the seal-like member (5) is rubbed with a spike to have a self-cleaning action of scraping off the toner deposited and deposited on the seal-like member 5.

JP-A-2005-37553 ("0032" to "0036", FIGS. 6 to 8 and FIG. 11) JP 2000-56566 A (“0053” to “0057”, FIGS. 11 and 12) Japanese Unexamined Patent Publication No. 2001-66887 ("0004" to "0008", "0024" to "0027", FIG. 2, FIG. 11, FIG. 12)

  An object of the present invention is to reduce the leakage of the developer in both the state where the developer holder holds the developer and rotates and the other state.

In order to solve the technical problem, in the developing device according to claim 1,
A developer accommodating portion in which the developer is accommodated;
A developer holding body that holds the developer on the surface and rotates to develop the latent image formed on the surface of the image holding body into a visible image;
A layer thickness regulating member which is supported by the developer accommodating portion and regulates the thickness of the developer layer held on the surface of the developer holding body;
The upstream side in the rotation direction of the developer holder relative to the closest position between the image carrier and the developer holder, and the closest position between the layer thickness regulating member and the developer holder. A first leakage preventing member disposed on the downstream side in the rotation direction of the developer holding body and having one end contacting the image holding body to prevent leakage of the developer;
In a state where the developer holding member is disposed between the layer thickness regulating member and the first leakage preventing member with respect to the rotation direction of the developer holding member, and one end portion is not held on the surface of the developer holding member. The developer holder is held on the developer holder when it is in contact with the surface of the developer holder and is not in contact with the first leakage prevention member , and the developer is held on the surface of the developer holder and rotating. A second leakage preventing member that is pressed by the developer and contacts the first leakage preventing member;
It is provided with.

In order to solve the technical problem, in the image forming apparatus of the invention according to claim 2 ,
An image carrier on which a latent image is formed on the surface;
The developing device according to claim 1, wherein the latent image on the surface of the image carrier is developed 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;
With
The image holding member rotates in a direction opposite to the rotation direction of the developer holding member, and the second leakage preventing member is held by the developer holding member via the first leakage preventing member. It is characterized by pressing toward.

  According to the first aspect of the present invention, as compared with the case where the configuration of the present invention is not provided, the developer holding member is rotated while holding the developer and the developer in both the other states Leakage can be reduced.

According to the invention described in claim 2, as compared to the case not having the constitution of the present invention, the developer holding member is a developer in the state and other state and both are rotating while holding a developer Leakage can be reduced.

Next, examples which are specific examples of embodiments of the present invention will be described with reference to the drawings, but 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, the image forming apparatus U includes an automatic document feeder U1 and an image forming 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 stores a plurality of documents Gi to be copied, and a document feeding unit TG1 that is fed from the document feeding unit TG1 and passes a document reading position on the document reading surface PG. And a document discharge portion TG2 from which the document Gi conveyed is discharged.
The image forming 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 red R, green G, and blue B electrical signals.
The image information conversion unit IPS converts the RGB electrical signals input from the solid-state imaging device CCD into black K, yellow Y, magenta M, and cyan C image information and temporarily stores them, and stores the image information in a predetermined manner. Is output to the latent image forming apparatus driving circuit DL as image information for forming a latent image.
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 device driving circuit DL.
The latent image forming device drive circuit DL has drive circuits for respective colors Y, M, C, and K (not shown), and signals corresponding to input image information are arranged for each color at a predetermined time. Output to the image forming apparatuses LHy, LHm, LHc, and LHk.

FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment.
Visible image forming devices Uy, Um, Uc, and Uk arranged at the center of the image forming device U in the gravitational direction are devices that form visible images of colors Y, M, C, and K, respectively.
The Y, M, C, and K latent image writing lights Ly, Lm, Lc, and Lk emitted from the latent image writing light sources of the latent image forming apparatuses LHy to LHk rotate as an example of an image carrier. The light enters the photosensitive drums PRy, PRm, PRc, and PRk. In Example 1, the latent image forming apparatuses LHy to LHk are configured by an LED array as an example of the latent image forming apparatus.
The Y visible image forming device Uy includes a rotating photoconductor drum PRy, a charger CRy, a latent image forming device LHy, a developing device Gy, a transfer device T1y, and a photoconductor cleaner CLy as an example of an image carrier cleaner. Have. In the first embodiment, the photosensitive drum PRy, the charger CRy, and the photosensitive cleaner CLy are configured as an image holding unit that can be integrally attached to and detached from the image forming apparatus main body U2.
The visible image forming apparatuses Um, Uc, Uk are all configured in the same manner as the Y visible image forming apparatus Uy.

1 and 2, the photosensitive drums PRy, PRm, PRc, and PRk are charged by their respective chargers CRy, CRm, CRc, and CRk, and then at image writing positions Q1y, Q1m, Q1c, and Q1k. An electrostatic latent image is formed on the surface of the latent image writing light Ly, Lm, Lc, Lk. The electrostatic latent images on the surfaces of the photosensitive drums PRy, PRm, PRc, and PRk are developed in the developing regions Q2y, Q2m, Q2c, and Q2k as developing roller as an example of a developer holding member of the developing devices Gy, Gm, Gc, and Gk. A toner image as an example of a visible image is developed with the developer held in R0y, R0m, R0c, and R0k.
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 supplied with a predetermined value from a power supply circuit E controlled by the control unit C. At this time, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied.

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

  Above the photosensitive drums PRy to PRk, a belt module BM is disposed as an example of an intermediate transfer device that can move up and down and can be pulled out forward. The belt module BM includes the intermediate transfer belt B, a belt drive roll Rd as an example of an intermediate transfer body drive member, a tension roll Rt as an example of an intermediate transfer body stretching member, and a walking roll as an example of a meandering prevention member. Rw, an idler roll Rf as an example of a driven member, a backup roll T2a as an example of a secondary transfer region facing member, and the primary transfer units T1y, T1m, T1c, T1k. The intermediate transfer belt B can be rotated by belt support rolls Rd, Rt, Rw, Rf, T2a as an example of an intermediate transfer member support member constituted by the rolls Rd, Rt, Rw, Rf, T2a. It is supported by.

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, and a secondary transfer device T2 is configured by the rolls T2a and T2b. ing. Further, a secondary transfer region Q4 is formed in a region where the secondary transfer roll T2b and the intermediate transfer belt B are opposed to each other.
The single-color or multi-color toner images transferred in sequence on the intermediate transfer belt B by the primary transfer units T1y, T1m, T1c, and T1k in the primary transfer areas Q3y, Q3m, Q3c, and Q3k are the secondary transfer areas. Transported to 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 according to the first exemplary embodiment.

  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 rails GR are fed as an example of a paper feed container. The trays TR1 to TR3 are supported so as to be able to enter and exit in the front-rear direction. The recording sheets S as an example of media stored in the paper feed trays TR1 to TR3 are taken out by a pick-up roll Rp as an example of a medium take-out member, and are separated one by one by a separating roll Rs as an example of a medium spreading 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 transferred transfer area conveyance timing 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 has a polarity opposite to the toner charging polarity 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 pressure 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 pressing fixing member. And heated and fixed when passing through the fixing region. 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 portion.
Note that a release agent for improving the releasability of the recording sheet S from the heating roll is applied to the surface of the heating roll Fh by a release agent application device Fa.

  Above the belt module BM, developer cartridges Ky, Km, Kc, and Kk are disposed as an example of a developer supply container that stores yellow Y, magenta M, cyan C, and black K developers. The developer accommodated in each developer cartridge Ky, Km, Kc, Kk is supplied from the developer supply path, which will be described later, to each developer Gy according to consumption of the developer in the developers Gy, Gm, Gc, Gk. , Gm, Gc, Gk. In Example 1, the developer is composed of a two-component developer including a magnetic carrier and a toner provided with an external additive.

In FIG. 1, the image forming apparatus U includes an upper frame UF and a lower frame LF, and the upper frame UF includes the visible image forming apparatuses Uy to Uk and the visible image forming apparatus Uy. A member arranged above -Uk, that is, a belt module BM and the like are supported.
The lower frame LF includes a guide rail GR that supports the paper feed trays TR1 to TR3 and the paper feed members that feed paper from the trays TR1 to TR3, that is, a pickup roll Rp, a separation roll Rs, A sheet conveying roll Ra and the like are supported.

(Description of developing device)
3A and 3B are explanatory views of the developing device according to the first embodiment of the present invention. FIG. 3A is an explanatory 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. It is explanatory drawing of an auger.
4 is a cross-sectional view taken along line IV-IV in FIG. 3A and is an explanatory diagram in a state where the developer is not attached to the developer holding member.
Next, the developing devices Gy, Gm, Gc, and Gk of 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 disposed to face the photosensitive drum PRy includes a developing container V that is an example of a developer containing portion that contains a two-component developer containing toner and a carrier. ing. The developer container V includes a developer container body 1, a developer container cover 2 as an example of a lid member that closes the upper end of the developer container body 1 as shown in FIG. 4, and a front end of the developer container body 1 as shown in FIG. The developer supply / discard cylinder 3 as an example of the developer supply / discard member connected to the seal member and a seal support member 43 described later. In FIG. 4, the developing container V of Example 1 has an opening V1 corresponding to the developing region Q2y facing the photosensitive drum PRy, and is open.

2 to 4, the developer container main body 1 includes a developing roll chamber 4 as an example of a developer holding body containing portion and an example of a first developer containing chamber adjacent to the developing roll chamber 4 inside thereof. An example of the first developer chamber 6 and a second developer storage chamber disposed adjacent to the lower right side of the first agitator chamber 6 in order to reduce the size of the developer container V in the horizontal and vertical directions. As a second stirring chamber 7. A developing roll R0y as an example of a developer holder is accommodated in the developing roll chamber 4, and a part of the outer surface of the developing roll R0y is exposed to the photosensitive drum PRy side through the opening V1. The photoconductor drum PRy is disposed opposite to the photoconductor drum PRy. The developing roll R0y rotates in the clockwise direction in FIG. 4 and rotates so as to move in the order of the lower part in the gravitational direction, the developing region Q2y that is the closest part to the image carrier PRy, and the upper part in the gravitational direction. . As shown in FIG. 4, the rotation direction of the photosensitive drum PRy is set to be opposite to the rotation direction of the developing roll R0y.
A layer thickness regulating member 8 for regulating the layer thickness of the developer on the surface of the developing roll R0y is provided on the upstream side in the rotation direction of the developing roll R0y.
In FIG. 4, at both the front and rear end portions of the developing container V, the abutting member Va for setting the distance between the developing roll R0y and the photosensitive drum PRy to a predetermined distance on the side facing the photosensitive drum PRy. A so-called tracking member is supported.

  In FIG. 3, a feed / disposal chamber 6 a inside the developer supply / disposal cylinder 3 is connected to the front side of the first agitation chamber 6, and an interior of the developer supply / disposal cylinder 3 is connected to the front side of the second agitation chamber 7. The replenishment chamber 7a is connected. In FIG. 3, a developer replenishing port 3a for replenishing the developer from the developer cartridges Ky, Km, Kc, Kk is formed on the upper surface of the front end portion (+ X end portion) of the supply / disposal chamber 6a. Yes. Further, a developer discharge port 3b as an example of a developer discharge portion is formed on the lower surface of the rear portion of the supply / disposal chamber 6a, and the waste developer that has been discharged from the developer discharge port 3b and dropped is not shown. It is collected in a developer collection container.

As shown in FIG. 3, in the developing container main body 1, a partition wall 9 is formed between the first stirring chamber 6 and the second stirring chamber 7 at a portion other than both end portions. 3 and 4, the first stirring chamber 6 and the second stirring chamber 7 include a rising inflow portion E1 as an example of a first inflow portion disposed at the rear end portion and a second inflow portion disposed at the front side. This is communicated with a descending inflow portion E2 as an example of the portion, and is configured such that the developer can be circulated. An opening forming member 11 having an opening for adjusting the amount of inflow is attached to the descending inflow portion E2.
Further, in the developer supply / discharge cylinder 3, a partition wall 12 is formed between the supply / discharge chamber 6a and the replenishment chamber 7a. Therefore, as shown in FIG. 3, the supply / disposal chamber 6a and the replenishment chamber 7a are connected by a replenishment inflow portion E3 as an example of the third inflow portion, and the developer flows into the replenishment chamber 7a from the supply / disposal chamber 6a. It is configured to be possible.
The first stirring chamber 6 and the second stirring chamber 7 constitute a circulation stirring chamber (6 + 7).

3 and 4, a supply auger 21 as an example of a supply member that conveys the developer while stirring and supplies the developer to the developing roll R <b> 0 y is disposed in the first stirring chamber 6.
3A and 3B, the supply auger 21 includes a first rotating shaft 22 extending parallel to the axial direction of the developing roll R0y, and a spiral first conveying blade supported on the outer periphery of the first rotating shaft 22. 23. The first conveying blade 23 includes a reverse conveying blade 23a for replenishment arranged corresponding to the front end portion of the supply / disposal chamber 6a, and a fourth conveying member arranged corresponding to the rear portion from the central portion of the supply / disposal chamber 6a. Disposal conveyance blade 23b as an example, reverse conveyance portion disposed corresponding to the rear end portion of the feed and waste chamber 3a and the front side of the descending inflow portion E2, and the reverse conveyance blade for circulation as an example of the third conveyance member 23c and a first main stirring and conveying blade 23d as an example of a first conveying member disposed corresponding to the rear end of the first stirring chamber 6 from the descending inflow portion E2.

  In the first embodiment, each of the blades 23a to 23d is formed in a spiral shape, and the distance that the developer moves by one rotation of the first main stirring and conveying blade 23d, that is, the blade adjacent in the axial direction. The interval between the so-called pitches is set to be larger than that of the conveying blades 23a to 23c. In the first embodiment, in the supply auger 21, the first rotating shaft 22 and the first conveying blade 23 are integrally formed of resin. However, the shaft and the conveying blade can be separately assembled and assembled. is there. Further, in the first embodiment, each of the blades 23a to 23d is provided on one first rotating shaft 22, but is not limited to this configuration. For example, the replenishment reverse conveying blade 23a, its rotating shaft, and disposal It is possible to configure separately such as the conveying blade 23b and its rotating shaft, the reverse conveying blade 23c for circulation and its rotating shaft, the first main stirring and conveying blade 23d and its rotating shaft.

  3A and 3C, a stirring auger 26 as an example of a stirring member that conveys the developer while stirring is disposed in the second stirring chamber 7. The stirring auger 26 includes a second rotating shaft 27 extending along the axial direction of the developing roll R0y, and a spiral second conveying blade 28 supported on the outer periphery of the second rotating shaft 27. The second conveying blades 28 are a replenishing conveying blade 28a arranged corresponding to the replenishing chamber 7a, and a second main agitating conveying blade 28b arranged correspondingly from the descending inflow portion E2 to the front side of the rising inflow portion E1. And a reverse conveying blade 28 c disposed at the rear end of the second stirring chamber 7.

In the first embodiment, the blades 28a to 28c are formed in a spiral shape, and the pitch of the second main stirring and conveying blades 28b is set larger than the pitch of the conveying blades 23a to 23c. In addition, as shown in FIG. 3, a plurality of flat stirring members 28 d are supported on the second rotating shaft 28 at predetermined intervals in the region where the second main transport blades 28 b are provided. . In FIG. 3C, a stirring paddle 28e as an example of a stirring unit is supported on the second rotating shaft 28 on the left side of the reverse conveying blade 28c. The stirring member 28d and the stirring paddle 28e have a greater conveying force in the circumferential direction than the conveying force along the axial direction of the second rotating shaft 28. In particular, in the first embodiment, the second rotating shaft 28, there is almost no conveying force in the axial direction by the stirring member 28d and the stirring paddle 28e.
In addition, the stirring auger 26 of the first embodiment is also integrally formed in the same manner as the supply auger 21. Furthermore, in the first embodiment, each of the blades 28a to 28c is provided on one second rotating shaft 27, but is not limited to this configuration. For example, the replenishing conveying blade 28a and its rotating shaft, The main agitating and conveying blade 28b and its rotating shaft, the reverse conveying blade 28c and its rotating shaft, etc. can be configured separately.

When each of the transport members 21 and 26 rotates, the developer replenished from the developer replenishing port 3a flows into the replenishment inflow portion E3 by the replenishment reverse transport blade 23a and the disposal transport blade 23b, and enters the replenishment chamber 7a. Be transported. The developer conveyed to the replenishing chamber 7a is conveyed to the second stirring chamber 7 in the developing container body 1 by the replenishing conveying blade 28a, and is conveyed to the second developer conveying direction Ya by the second main conveying blade 28b. The The developer conveyed to the rising inflow portion E1 is retained and increases in developer amount by the second main conveyance blade 28b and the reverse conveyance blade 28c conveyed in the direction opposite to the second developer conveyance direction, It flows into the first stirring chamber 6 obliquely above.
The developer that has flowed into the first stirring chamber 6 is conveyed by the first main conveying blade 23d in the first developer conveying direction Yb opposite to the second developer conveying direction Ya. The developer conveyed through the first stirring chamber 6 adheres to the surface of the developing roll R0y during conveyance and is used for development. The developer conveyed to the descending inflow portion E2 is retained in the descending inflow portion E2 by the reverse conveying blade 23c for circulation to try to convey the developer in the direction opposite to the first developer conveying direction Yb, and descends due to gravity. It flows into the second stirring chamber 7 through the inflow portion E2. As a result, the developer in the stirring chambers 6 and 7 is circulated and conveyed while being stirred by the stirring members 21 and 26.
Further, when the developer in the descending inflow portion E2 increases, a part of the developer may not be transported in the reverse direction by the circulation reverse transport blade 23c, and may flow into the waste transport blade 23b on the supply / disposal chamber 7a side. In this case, the developer that has flowed into the waste transport blade 23b beyond the circulation reverse transport blade 23c is transported to the developer discharge port 3b by the waste transport blade 23b and discarded.

(Explanation of layer thickness regulating member and leakage preventing member)
FIG. 5 is a perspective explanatory view of a leakage preventing member and a leakage preventing member fixing member according to the first embodiment.
FIG. 6 is an explanatory view showing a state in which the leakage preventing member and the leakage preventing member fixing member are supported by the layer thickness regulating member.
FIG. 7 is an explanatory diagram of the developing device according to the first exemplary embodiment of the present invention, and is an explanatory diagram of a state where the developer adheres to the developer holding member.
4 to 7, the layer thickness regulating member 8 has a plate-like regulating member main body 8a extending in the radial direction of the developing roll R0y, and a tip of the regulating member main body 8a facing the developing roll R0y A layer thickness regulating portion 8b that regulates the layer thickness of the developer held on the surface of the developing roll R0y to a predetermined thickness is formed. In FIG. 6, the layer thickness regulating member main body 8a is formed with support holes 8c as an example of a plurality of fixing member support portions along the axial direction of the developing roll R0y. The layer thickness regulating member 8 is fixedly supported on the developing container main body 1 at both ends by screws (not shown).

  4 to 7, a base member 41 as an example of a leakage preventing member fixing member is disposed on the photosensitive drum PRy side of the layer thickness regulating member 8. The base member 41 includes a supported portion 42 formed facing the lower portion of the layer thickness regulating member main body 8a and a seal as an example of a leakage prevention member supporting portion integrally formed on the upper portion of the supported portion 42. And a support member 43. The supported portion 42 has a protruding fixed portion 42a formed corresponding to the support hole 8c. In Example 1, the base member 41 is fixedly supported by the layer thickness regulating member 8 by fixing the protruding fixed portion 42a in the support hole 8c while being press-fitted.

The seal support member 43 has a space in which air swirls with the layer thickness regulating member 8 in a state where the base member 41 is mounted on the layer thickness regulating member 8 on the right side on the layer thickness regulating member 8 side. The space formation part 43a which forms the substantially V-shaped eddy current generation space V2 as an example is formed. A second seal support portion 43b as an example of a second support portion is formed on the left side surface extending above the space forming portion 43a. An eddy current generation space forming area as an example of an upstream facing area facing the developing roll R0y is set in an area from the space forming portion 43a to the second seal support member 43b along the rotation direction of the developing roll R0y. The eddy current generation space V2 is constituted by a space surrounded by the left wall surface of the layer thickness regulating member 8, the wall surface of the space forming portion 43a, and the wall surface of the second seal support portion 43b.
The seal support member 43 is an example of a facing region facing the developing roll R0y, and is a contact surface 43c formed along the outer surface of the developing roll R0y continuously from the upper end of the second seal support portion 43b. Have 4 and 7, in Example 1, the contact surface 43c is in relation to a virtual tangent L0 along the direction of gravity drawn from the surface of the photosensitive drum PRy at the closest position between the developing roll R0y and the photosensitive drum PRy. The virtual tangent line L0 is not crossed.
Further, the seal support member 43 has an image carrier facing surface 43d that extends from the upper end of the contact surface 43c obliquely downward along the surface of the photosensitive drum PRy. At the lower end of the image carrier facing surface 43d, there is a first seal support portion 43e as an example of a first support portion extending continuously downward at the left portion of the seal support member 43.

  4 to 7, the first seal support portion 43e is flexible as an example of a first leakage prevention member in order to prevent the developer from leaking downward from the development region Q2y. A first seal member 46 that is elastically deformable is supported. The first seal member 46 has a base portion 46a on one end side supported by a first seal support portion 43e by an adhesive member such as a double-sided tape, and a free end portion 46b on the other end side in contact with the surface of the photosensitive drum PRy. Thus, the developer is prevented from leaking from the developing area Q2y to the latent image forming apparatuses LHy to LHk below. The adhesive member is not limited to a double-sided tape, and an adhesive can be used. Also, the adhesive member is not limited to the case of using an adhesive member, and any fixing method such as heat fusion or screwing can be adopted. It is.

A flexible, elastically deformable second seal member 47 is supported on the second seal support portion 43b as an example of a second leakage prevention member. That is, in the first embodiment, the second seal member 47 is disposed between the layer thickness regulating member 8 and the first seal member 46 with respect to the rotation direction of the developing roll R0y. The second seal member 47 includes a base portion 47a on one end side supported by an adhesive member on the second seal support portion 43b, and a free end portion 47b on the other end side.
In Example 1, as shown in FIG. 4, the free end 47b is set to contact the surface of the developing roll R0y when the developer is not held on the surface of the developing roll R0y.
Further, as shown in FIG. 7, when the developer is held on the surface of the developing roll R0y and rotated as in the image forming operation, the layer thickness regulating member 8 regulates it to a predetermined layer thickness, It is set so that it is pushed by the developer held on the developing roll R0y and comes into contact with the first seal member 46.

  4 and 7, the developing container cover 2 that closes the upper surface of the developing container V of the first embodiment includes a second upper wall surface 2 a of the second stirring chamber 7 formed in an arc shape along the outer shape of the stirring auger 26. The partition wall portion 2b that partitions the first stirring chamber 6 and the second stirring chamber 7 by fitting the partition wall 9, and the upper wall surface of the first stirring chamber 6 and the upper wall surface of the developing roll chamber 4 are configured. It has an upper wall surface 2c and a developer holder housing wall 2d surrounding the developing roll R0y. The developer holding member housing wall 2d is formed so that its inner peripheral surface surrounds the developing roll R0y, and at the opening 2d1 constituting the upper end of the opening V1, it goes to the outside, that is, toward the photosensitive drum PRy. Accordingly, the distance to the surface of the developing roll R0y is increased.

(Operation of Example 1)
In the image forming apparatus U of Example 1 having the above-described configuration requirements, when the developing devices Gy to Gk are activated by an image forming operation, the developing rolls R0y to R0k rotate while holding the developer on the surface. The developer held on the surface of the developing rolls R0y to R0k is regulated to a predetermined layer thickness by the layer thickness regulating member 8, and is conveyed toward the developing regions Q2y to Q2k. In the development areas Q2y to Q2k, the electrostatic latent images formed on the surfaces of the photosensitive drums PRy to PRk are developed into visible images. In the development areas Q2y to Q2k, the developer floats in a so-called cloud shape and is developed, and a part of the developer falls downward due to gravity.

In Embodiment 1, the developer is prevented from leaking out by the first seal member 46 disposed in contact with the photosensitive drums PRy to PRk, and is prevented from falling toward the lower latent image forming apparatuses LHy to LHk. Is done.
Further, the second seal member 47 is pressed and bent by the developer held on the surface of the developing rolls R0y to R0k, and comes into contact with the surface of the developing rolls R0y to R0k shown in FIG. 4, as shown in FIG. The base 47a side of the free end 47b is supported in contact with the contact surface 43c, the tip of the free end 47b is in contact with the first seal member 46, and the free end 47b is in contact with the first seal member 46. At this position, the first seal member 46 is held without contacting the photosensitive drums PRy to PRk. Therefore, when the developing rolls R0y to R0k are not rotating while holding the developer, the second seal member 47 pushes the developer toward the developing rolls R0y to R0k by the elastic restoring force, so that the developing rolls R0y to R0k are moved. A gap generated between the held developer and the second seal member 47 is reduced. In addition, when the developing rolls R0y to R0k are rotating while holding the developer, the tip of the second seal member 47 comes into contact with the first seal member 46, so that the development held by the developer holding body is performed. When the tip of the second seal member 47 whose pressure changes according to the amount of the agent contacts the surface of the photosensitive drums PRy to PRk, unevenness in the influence on the electrostatic latent image is reduced.

  Further, in the first embodiment, the second seal member 47 contacts the first seal member 46, and the developer is placed in the space V3 surrounded by the second seal member 47, the first seal member 46, and the image carrier facing surface 43d. Is prevented from adhering and accumulating. Therefore, in the configuration in which the second seal member 47 does not contact, the developer accumulated in the space V3 adheres to the developing rolls R0y to R0k, the layer thickness changes, and an image defect occurs. In 1, the occurrence of image defects is reduced.

The second seal member 47 is in contact with the developing rolls R0y to R0k in a state where the developer is not attached to the surfaces of the developing rolls R0y to R0k, and the developer is attached to the surfaces of the developing rolls R0y to R0k. In this state, the developer is pushed by the elastic restoration of the second seal member 47. Therefore, the entire surface of the second seal member 47 is reliably rubbed with the developer having a predetermined layer thickness held on the surface of the rotating developing rolls R0y to R0k. That is, in the case of the conventional configuration in which the second seal member is formed in a curved shape along the outer peripheral surface of the developing rolls R0y to R0k, and the second seal member is not deformed by being pushed by the developer, the developing rolls R0y to R0k. In some cases, the surface of the second seal member may not be rubbed due to the wear of the layer thickness regulating member 8 or the amount of developer adhering to the developing rolls R0y to R0k. The surface of the seal member 47 is pressed against the developer, and the surface of the second seal member 47 is reliably rubbed and cleaned as the developing rolls R0y to R0k rotate.
Furthermore, in the first embodiment, the contact surface 43c is disposed so as not to cross the virtual tangent line L0, and the developer that has fallen from the development regions Q2y to Q2k is in contact with the contact surface 43c of the second seal member 47. Falling and flowing in between the developing rolls R0y to R0k is reduced, and a change in the thickness of the developer layer is reduced.

FIG. 8 is an explanatory diagram of a conventional image forming apparatus.
In the first embodiment, a contact surface 43c that is an inner wall surface of the seal support member 43 is formed between the layer thickness regulating member 8 and the second seal member 47 along the surface of the developing rolls R0y to R0k. . On the upstream side of the closest portion between the photosensitive drum PRy and the developing rolls R0y to R0k, the inner wall facing the developing rolls R0y to R0k is formed along the surface of the developing rolls R0y to R0k, thereby stabilizing the developer transport performance. In addition, the posture of the second seal member 47 in a state of contacting the first seal member 46 is maintained by functioning as the contact surface 43c. Further, in the upstream facing area upstream of the area where the inner wall facing the developing rolls R0y to R0k is formed along the surface of the developing rolls R0y to R0k, the developing rolls R0y to R0k and the inner wall surface of the seal support member 43 The eddy current generation space V2 is formed by forming a wide distance. Accordingly, as the developing rolls R0y to R0k rotate, the air on the surface of the developing rolls R0y to R0k moves to the downstream side so as to be involved in the rotation of the developing rolls R0y to R0k. Will occur. Accordingly, the developer at the downstream end of the layer thickness regulating portion 8b of the layer thickness regulating member 8 is transported to the downstream side and accumulated due to the flow of the spiral air. That is, in the conventional configuration shown in FIG. 8, the developer accumulates in the downstream portion of the layer thickness regulating portion 8b, and the accumulated developer adheres to the surface of the developing rolls R0y to R0k after the layer thickness regulation. Although the image quality may be deteriorated due to the change in thickness, in the first embodiment, the developer accumulation is reduced by the vortex generated in the vortex generation space V2. Further, the developer that has fallen into the vortex generation space V2 is carried on the vortex-like air flow and conveyed toward the developing rolls R0y to R0k, thereby preventing excessive accumulation of the developer. That is, in Example 1, accumulation of the developer in the layer thickness regulating portion 8b is prevented, and accumulation of the developer on the contact surface 43c is prevented, thereby reducing the occurrence of image quality defects.

  4 and 7, in Example 1, the distance between the opening 2d1 constituting the upper end of the opening V1 and the surface of the developing rolls R0y to R0k increases as it goes to the outer side of the photosensitive drum PRy. It is formed to become. In FIG. 8, when the wall surface 2e of the developing container extends along the developing rolls R0y to R0k to the vicinity of the developing regions Q2y to Q2k as in the conventional image forming apparatus, the developing regions Q2y to Q2k are clouded. In some cases, the developer adheres to the tip of the wall surface 2e and hangs down in an icicle shape, and the icicle-like developer falls into the development areas Q2y to Q2k at irregular times, thereby causing poor image quality. 4 and 7, in Example 1, the distance between the opening 2d1 and the surface of the developing rolls R0y to R0k increases as the opening 2d1 goes outward, and the tip of the opening 2d1 is developed. It is far from the areas Q2y to Q2k. Therefore, when the developer hardly adheres to the tip of the opening 2d1 and the developer temporarily adheres to the inner part of the opening 2d1 that is close to the developing rolls R0y to R0k, the dropped developer is It does not fall into the development areas Q2y to Q2k, but falls and adheres to the surface of the development rolls R0y to R0k, and returns to the inside of the development container V as the development rolls R0y to R0k rotate, thereby reducing the adverse effects on image quality. Has been.

(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 (H06) of the present invention are exemplified below.
(H01) In the above-described embodiment, the copying machine as the image forming apparatus has been illustrated. However, the present invention is not limited to this, and a FAX, a printer, or a multifunction machine having all or a plurality of functions may be used. Further, although the image forming apparatus having the photosensitive drums PRy to PRk for four colors, the developing units Gy to Gk, and the latent image forming apparatuses LHy to LHk is illustrated, the present invention is not limited to this, and a single color image forming apparatus, The present invention can also be applied to a rotary image forming apparatus in which a single drum and a latent image forming apparatus are provided and four developing devices rotate and sequentially face the photosensitive drum. Further, the latent image forming apparatus is not limited to a so-called LED array, and a conventionally known latent image forming apparatus such as a latent image forming apparatus using a rotary polygon mirror can be used.

(H02) In the above embodiment, the vortex generating space V2 is preferably provided, but may be omitted. For example, a member or the like can be arranged to fill the eddy current generation space V2.
(H03) In the above-described embodiment, the shape of the opening 2d1 is preferably the shape illustrated in the embodiment, but may be configured similarly to the conventional one.
(H04) In the above-described embodiment, the developing devices Gy to Gk in which the second developer accommodating chamber 7 is disposed obliquely below the first developer accommodating chamber 6 are exemplified. Any configuration such as a configuration in which the agent storage chamber and the second developer storage chamber are arranged side by side in the vertical direction or a configuration in which the agent storage chamber and the second developer storage chamber are arranged in the horizontal direction can be adopted.

(H05) In the above embodiment, the method for supporting each leakage preventing member 46, 47 and the method for fixing the base member 41 to the layer thickness regulating member 8 are not limited to the methods exemplified in the embodiment, and any conventionally known arbitrary This method and configuration can be adopted.
(H06) In the above-described embodiment, the contact surface 43c is preferably arranged so as not to cross the virtual tangent line L0, but may be arranged so as to cross it.

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. 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 taken along line IV-IV in FIG. 3A and is an explanatory diagram in a state where the developer is not attached to the developer holding member. FIG. 5 is a perspective explanatory view of a leakage preventing member and a leakage preventing member fixing member according to the first embodiment. FIG. 6 is an explanatory view showing a state in which the leakage preventing member and the leakage preventing member fixing member are supported by the layer thickness regulating member. FIG. 7 is an explanatory diagram of the developing device according to the first exemplary embodiment of the present invention, and is an explanatory diagram of a state where the developer adheres to the developer holding member. FIG. 8 is an explanatory diagram of a conventional image forming apparatus.

Explanation of symbols

8: Layer thickness regulating member,
43 ... Leakage prevention member support member,
43a ... space forming part,
43b ... second support part,
43c ... contact surface,
43e ... 1st support part,
46. First leakage preventing member,
46a ... one end,
46b ... the other end,
47. Second leakage prevention member,
47a ... base,
47b ... free end,
F: Fixing device,
Gy, Gm, Gc, Gk ... developing device,
L0 ... Virtual tangent,
PRy, PRm, PRc, PRk ... Image carrier,
R0y, R0m, R0c, R0k ... developer holder,
S ... medium,
T1 + T2 + B ... transfer device,
U: Image forming apparatus,
V: Developer container,
V2 ... Space where air swirls.

Claims (2)

A developer accommodating portion in which the developer is accommodated;
A developer holding body that holds the developer on the surface and rotates to develop the latent image formed on the surface of the image holding body into a visible image;
A layer thickness regulating member which is supported by the developer accommodating portion and regulates the thickness of the developer layer held on the surface of the developer holding body;
The upstream side in the rotation direction of the developer holder relative to the closest position between the image carrier and the developer holder, and the closest position between the layer thickness regulating member and the developer holder. A first leakage preventing member disposed on the downstream side in the rotation direction of the developer holding body and having one end contacting the image holding body to prevent leakage of the developer;
In a state where the developer holding member is disposed between the layer thickness regulating member and the first leakage preventing member with respect to the rotation direction of the developer holding member, and one end portion is not held on the surface of the developer holding member. The developer holder is held on the developer holder when it is in contact with the surface of the developer holder and is not in contact with the first leakage prevention member , and the developer is held on the surface of the developer holder and rotating. A second leakage preventing member that is pressed by the developer and contacts the first leakage preventing member;
A developing device comprising: An image carrier on which a latent image is formed on the surface;
The developing device according to claim 1, wherein the latent image on the surface of the image carrier is developed 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;
With
The image holding member rotates in a direction opposite to the rotation direction of the developer holding member, and the second leakage preventing member is held by the developer holding member via the first leakage preventing member. An image forming apparatus, wherein the image forming apparatus is pressed toward.

Images