JP2005301189A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of keeping excellent image quality by restraining the variance of toner concentration by autonomously correcting the deviation of developer distribution even when the developing device or an image forming apparatus on which the developing device is mounted is arranged to be tilted to a horizontal direction. <P>SOLUTION: In the developing device 24 constituted so that two-component developer G separated to a developer retreating section 34 may flow out to a developer storing section 33 or a toner storing section 35, a plurality of partition members 42 restraining the movement of the two-component developer G along the shaft direction of a developer carrier 32 are provided to orthogonal to the developer carrier 32 at least at the developer retreating section 34. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine having these functions, to which an electrophotographic system is applied, and in particular, a two component having a magnetic carrier and a toner. The present invention relates to an improvement of a developing device that uses a developer and can autonomously control the toner density without using a toner density detecting means.

Japanese Patent Publication No. 5-67233 JP-A-5-119625 Japanese Patent Laid-Open No. 9-22178 JP 2000-352877 A JP-A-9-197833

  Conventionally, as a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine having these functions to which this kind of electrophotographic method is applied, it is formed on an image carrier such as a photosensitive drum. It is known that the electrostatic latent image formed is visualized with a developer. As a developing method used in such a developing apparatus, a one-component developing method using only toner that is colored particles as a developer, and a two-component method using a mixture of magnetic particles and toner that is colored particles as a developer. Roughly divided into development methods.

  The above two-component developing system has many excellent points such as image quality, cost, and stability. Therefore, there is a wide range of magnetic brush developing systems that develop a toner mixed with a magnetic carrier while conveying the developer by magnetic force. It has been adopted. In this magnetic brush development system, the toner is carried on the surface of the magnetic carrier by the electrostatic force generated by the friction between the toner and the magnetic carrier. When this toner approaches the electrostatic latent image on the image carrier, By flying on the electrostatic latent image by the electric field formed by the electrostatic latent image, the electrostatic latent image is visualized. Further, the developer is repeatedly used while replenishing the toner consumed by the development.

  However, in such a magnetic brush development system, if the toner density (mixing ratio of toner and magnetic carrier) is not controlled to be within a certain range, toner scattering and fogging occur when the toner density increases. On the other hand, when the toner density is lowered, density spots and image omissions occur. Therefore, in order to obtain a stable image, it is necessary to keep the toner density constant.

  Therefore, in the conventional magnetic brush developing system, in order to obtain a stable image, a toner density sensor and a toner replenishing member are mounted on the developing device and control is performed to keep the toner density constant. For example, the toner density is detected by the toner density sensor, and after determining that the toner density has decreased based on the detection information, the toner supply is performed by the toner supply member.

  However, in this type of magnetic brush developing system, a toner density sensor and a toner replenishing member are indispensable, and an increase in the size and cost of the developing device cannot be avoided. Also, there is a problem that the toner density detection system is troublesome, such as creating a density patch to be detected.

  As a prior art for solving such problems, there has already been proposed a developing device that maintains a constant toner concentration without using a toner concentration sensor or a toner replenishing member. The developing device includes a developer accommodating portion that accommodates a two-component developer, and a toner accommodating portion that communicates with the developer accommodating portion and accommodates toner, and the amount of the two-component developer on the developer carrier is set. It is configured to regulate the toner concentration by regulating the toner by autonomously controlling the toner intake of the two-component developer according to the change in the toner concentration of the two-component developer on the developer carrying member. is there.

  This autonomous toner density control method generates a developer moving layer carried and conveyed by a developer carrying member and a developer circulating layer in which the developer circulates in the developer containing portion. The toner is taken in from the communicating toner container. In other words, when the toner is consumed in the developing process, the volume of the developer stored in the developer container is reduced, and the reduced amount of toner is supplied from the toner container to the developer container. In other words, the developer in the developer container holds the toner concentration.

  As an example of the developing device, in the technique disclosed in Patent Document 1, a magnetic particle layer is formed on a developing sleeve, and toner is accommodated in the toner supply unit in the container so as to be in contact with the magnetic particle layer. By the movement of the magnetic particles in the magnetic particle layer accompanying the rotation of the sleeve, the toner supply unit takes in the toner from the outer toner layer into the magnetic particle layer, and the developer in which the toner and the magnetic particles are mixed is used by the regulating member. By restricting the layer thickness and transporting it to the developing unit, charging is prevented from being insufficient due to excessive supply of toner.

  In the technique disclosed in Patent Document 2, in the developing sleeve rotating type magnetic brush developing device having an internal magnetic pole, an insulating layer is provided on the surface of the developing sleeve, and a toner supply roll is provided near the developing sleeve. By applying an alternating voltage between the supply roll and the developing sleeve, the toner concentration and toner charging are stabilized.

  Furthermore, in the technique disclosed in Patent Document 3, magnetic toner is used as the toner constituting the developer, thereby stabilizing toner charging and preventing toner scattering. Further, in the technique disclosed in Patent Document 4, when the transport speed of the developer carrying member is the fastest, the toner is set so that the toner concentration is below the limit toner concentration where the toner is completely covered on the surface of one carrier. By configuring the density, it is possible to prevent background contamination and toner scattering.

  Further, in the technique disclosed in Patent Document 5, in the developer accommodating portion, the developer carrying member in the developer carrying direction upstream of the first regulating member that regulates the amount of developer carried and carried by the developer carrying member. By providing a second regulating member on the side, the toner density adjustment is facilitated

  However, in each of the above prior arts, the toner concentration is controlled by the change in the developer volume corresponding to the change in the toner concentration and the movement of the developer. The movement needs to be noticeable.

  Under such a demand, it is necessary to increase the developer density in the developer container around the developer carrier with a small amount of developer as compared with the normal two-component development method. The circulation is poor, and there are portions where the developer moves actively and portions where the movement of the developer is not active, so that the toner is not uniformly taken in. In addition, since the amount of developer is small, the absolute amount of toner contained in the developer is small, and because the developer density is high, the volume fluctuation of the developer is gradual even if the toner concentration is reduced, and the toner intake speed is increased. Due to the slowness, the toner is not sufficiently supplied onto the developer carrying member when continuously outputting high-density images with high toner consumption, and a desired density cannot be obtained.

Furthermore, since the developer amount must be set small in advance, the stress applied to one magnetic carrier is increased, and the life of the magnetic carrier is shortened. That is, the running cost increases, and the response is slow, which causes a problem that the density of the high-density image cannot be secured.

  Therefore, the present applicant has already proposed a developing device as shown in FIG. 21 in order to solve the above problems.

  As shown in FIG. 21, the developing device 100 according to Japanese Patent Application No. 2003-280354 includes a magnetic field generating means 102 inside and carries a two-component developer G containing toner and a magnetic carrier. A developer carrier 101, a developer container 103 for accommodating the two-component developer G adjacent to the developer carrier 101, and a part of the developer container 103 near the developer carrier 101. Adjacent to the developer carrying member 101, the developer agitating member 104 provided, a toner containing unit 105 that is provided in communication with the developer carrying member 101 via the developer containing unit 103, and that accommodates toner so as to be supplied. A developer retracting portion 106 that is provided downstream of the developer carrying member 101 in the developer transport direction with respect to the developer containing portion 103 and communicates with the developer containing portion 103, and the developer collecting portion. A part of the two-component developer G provided on the downstream side of the developer carrying member 101 in the developer carrying direction with respect to the portion 103 and the developer retracting unit 106 and carried and carried by the developer carrying member 101 is used as an excess developer. The two-component developer G separated into the developer retracting section 106 is provided with a developer separating means 107 for separating the surplus developer in the developer accommodating section 103 or the developer retracting section 106 according to the damming and toner density. Is configured to flow out to the developer accommodating portion 103.

  However, the conventional technique has the following problems. That is, in the case of the developing device 100 according to Japanese Patent Application No. 2003-280354, the image forming apparatus on which the developing device 100 is mounted is disposed in a state inclined along the longitudinal direction of the developing device with respect to the horizontal direction. When the developing device 100 is installed with an inclination along the longitudinal direction, the two-component developer G in the developer accommodating portion 103 is placed on one end side in the longitudinal direction of the developing device 100 due to the influence of gravity. Along the bias. In the developing device 100, when toner is supplied from the toner storage unit 105 to the developer storage unit 103, the toner concentration of the two-component developer G in the developer storage unit 103 is changed in the longitudinal direction of the developing device 100. There are problems such as non-uniformity, fogging on the image, character thickening, and character scattering.

  More specifically, in the case of the developing device 100 according to Japanese Patent Application No. 2003-280354, the image forming apparatus on which the developing device 100 is mounted is inclined along the longitudinal direction of the developing device 100 with respect to the horizontal direction. When the developing device 100 is installed with an inclination along the longitudinal direction, the two-component developer G in the developer accommodating portion 103 is biased along the inclination of the developing device 100.

  Moreover, in the developing device 100, when the toner concentration in the developer accommodating portion 103 becomes low, the developer G is scraped off by the developer separating means 107, and the overflowing developer G is applied to the inclined portion of the developer separating means 107. However, since the inclined portion of the developer separating means 107 is also inclined along the longitudinal direction as the developing device 100 is inclined, the developing device flows when the developer flows along the inclined portion. It will flow towards the lower part along the 100 slope. As a result, the developer G flowing on the inclined portion of the developer separating means 107 flows toward a lower portion along the inclination of the developing device, so that the amount of developer in the lower portion along the inclination of the developing device 100 is large. Therefore, the amount of developer at a high portion decreases along the inclination.

  In the portion where the amount of developer increases, the developer in the connecting portion 103a of the developer accommodating portion 103 with the toner accommodating portion 105 becomes excessive, so that the supply of toner from the developer accommodating portion 105 is hindered, The toner concentration in the developer storage unit 103 remains low. On the contrary, in the portion where the amount of the developer is reduced, the connecting portion 103a of the developer containing portion 103 with the toner containing portion 105 is in a state where the developer is small or in an extreme case, there is no developer at all. As a result, an excessive amount of toner is supplied from 105, and the toner density in the developer storage unit 103 increases. Therefore, when the developing device 100 is disposed in a state where the developing device 100 is inclined along the longitudinal direction, the toner concentration of the two-component developer G in the developer containing portion 103 is not balanced with the developer amount. Along with this, the developing device 100 becomes non-uniform in the longitudinal direction, and fogging occurs on the image in a portion where the toner density is high, character thickening or scattering of characters occurs, and density spots and spots are observed in a portion where the toner density is low. There is a problem that image omission occurs.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a developing device and an image forming apparatus on which the developing device is mounted in a horizontal direction. It is an object of the present invention to provide a developing device capable of maintaining a good image quality by autonomously correcting the deviation of the developer distribution and suppressing the fluctuation of the toner density even when arranged in an inclined manner.

  In order to solve the above-described problems, the invention described in claim 1 includes a developer carrying member that includes a magnetic field generating unit therein and conveys and carries a two-component developer including a toner and a magnetic carrier, A developer accommodating portion for accommodating a two-component developer adjacent to the developer bearing member; a developer agitating member disposed in a portion of the developer accommodating portion adjacent to the developer bearing member; and the developer accommodating portion. A toner container which is provided in communication with the developer carrier through which the toner is accommodated so that toner can be supplied; and adjacent to the developer carrier, the developer carrier is downstream in the developer transport direction with respect to the developer container. A developer retracting portion provided on a side of the developer containing portion and communicating with the developer accommodating portion; and a developer carrying member provided downstream of the developer accommodating portion with respect to the developer accommodating portion and the developer retracting portion. Of the two-component developer carried and conveyed by the body Two-component development separated into the developer retracting section, with a developer separating means for separating the surplus developer in the developer accommodating section or the developer retracting section according to the toner density In the developing device configured so that the developer flows out to the developer accommodating portion or the toner accommodating portion, the movement of the two-component developer along the axial direction of the developer carrying member is suppressed at least in the developer retracting portion. In the developing device, the plurality of partition members are provided so as to be orthogonal to the developer carrying member.

  The invention described in claim 2 is the developing device according to claim 1, wherein a plurality of partition members are provided on the developer stirring member so as to be orthogonal to the developer carrier. The developing device is characterized.

  Furthermore, the invention described in claim 3 is the developing device according to claim 1 or 2, wherein a plurality of partition members are provided in the developer accommodating portion so as to be orthogonal to the developer carrier. This is a developing device.

  Furthermore, the invention described in claim 4 is the developing device according to claim 1, wherein the partition member is capable of rotating in accordance with the inclination of the developing device in the axial direction. In the horizontal installation state, the center of gravity of the partition member is supported by a rotating shaft having torsional rigidity that enables restoration to a position substantially orthogonal to the developer carrying member. The developing device is arranged and formed to be above the rotation axis.

  Furthermore, the invention described in claim 5 is the developing device according to claim 4, wherein the rotation shaft of the partition member is disposed in the vicinity of the central portion in the longitudinal direction of the partition member. The developing device.

  According to the present invention, even when the developing device and the image forming apparatus on which the developing device is mounted are arranged to be inclined with respect to the horizontal direction, the bias in the developer distribution is corrected autonomously and the toner is corrected. It is possible to provide a developing device capable of maintaining good image quality by suppressing density fluctuations.

Embodiments of the present invention will be described below with reference to the drawings.
<Embodiment 1>

  FIG. 2 shows an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied.

  In FIG. 2, reference numeral 21 denotes an electrostatic latent image carrier made of an OPC photosensitive member that is rotationally driven along the direction of the arrow. The surface of the electrostatic latent image carrier 21 has a scorotron or a charging surface. It is charged by a charging device 22 such as a roll, and an electrostatic latent image is written by an exposure device 23 having a laser writing device or an LED array. This electrostatic latent image is formed as a potential image based on the contrast with a high potential portion not exposed to light because the surface potential of the electrostatic latent image carrier 21 exposed to light is lowered.

  The developing device 24 accommodates a two-component developer comprising a toner and a carrier is colored particles in the developing housing 31, it is supported with the two-component developer to the developer carrying member 32, the developer carrying member 32 a by applying a developing bias from a bias power source 25, to hold the developer carrying member 32 to an intermediate potential between the high potential portion and a low-potential portion of an electrostatic latent image, it is charged image portions of the electrostatic latent image The toner is developed with toner.

  Further, the transfer device 26 is constituted by, for example, a transfer roll disposed in contact with the electrostatic latent image carrier 21, and a transfer bias in a direction in which the toner image on the electrostatic latent image carrier 21 is attracted by the bias power source 27. Is applied so that the toner image on the electrostatic latent image carrier 21 is transferred to the recording material 28. The toner remaining on the electrostatic latent image carrier 21 is removed by, for example, a doctor blade type cleaning device 29.

  Further, the recording material 28 onto which the toner image is transferred from the electrostatic latent image carrier 21 is conveyed to a fixing device 50, and the toner image is fixed to the recording material 28 by the fixing device 50. The fixing device 50 includes a heat roll method for example, a heating roller 51 and the pressure roll 52, a recording material a toner image by passing the recording material 28 between the heating roll 51 and pressure roll 52 28 is fixed.

  FIG. 1 shows a developing apparatus according to Embodiment 1 of the present invention.

  The developing device includes a developer carrier having a magnetic field generating means therein and carrying and carrying a two-component developer containing toner and a magnetic carrier, and a two-component developer adjacent to the developer carrier. A developer accommodating portion to be accommodated; a developer agitating member disposed in a portion of the developer accommodating portion close to the developer carrying member; and a developer carrying member provided in communication with the developer accommodating portion. A toner storage unit that stores toner in a supplyable manner, and is provided adjacent to the developer carrier and downstream of the developer carrier in the developer transport direction with respect to the developer carrier, and communicates with the developer storage unit. A part of the two-component developer that is provided on the downstream side in the developer transport direction of the developer carrier relative to the developer retracting part and the developer accommodating part and the developer retracting part and is carried and transported by the developer carrier. Dampen as excess developer, toner And a developer separating means for separating the excess developer in the developer accommodating portion or the developer retracting portion according to the degree, and the two-component developer separated into the developer retracting portion is the developer accommodating portion or the toner. It is comprised so that it may flow out to a storage part.

  That is, as shown in FIG. 1, the developing device 24 includes a developing housing 31 having an opening at a position facing the electrostatic latent image carrier 21, and faces the opening of the developing housing 31. A developer carrying member 32 is disposed, and a developer containing portion 33 for containing the two-component developer G and a developer carrying member 32 are disposed in a portion of the developing housing 31 adjacent to the developer carrying member 32. Adjacent to the developer container 33 and communicated with the developer carrier 32 via the developer container 33 and a developer retracting part 34 provided downstream of the developer carrier 32 in the developer transport direction. In addition, a toner storage portion 35 that stores the toner T is formed.

  The two-component developer G is a developer composed of a toner T and a magnetic carrier. As the toner T, for example, a non-magnetic toner is used. If the magnetic property is different from that of the magnetic carrier, a magnetic toner is used. It may be used.

  The developer carrying member 32 includes a rotatable rotating sleeve 321 disposed on the outer periphery and a magnetic pole roll 322 disposed in a fixed state inside the rotating sleeve 321. The rotating sleeve 321 is formed in a thin cylindrical shape from nonmagnetic stainless steel or the like. In addition, the magnetic pole roll 322 has, for example, a conveyance magnetic pole (S2 in this example) aligned with the right side of the horizontal plane passing through the roll body center O, and the conveyance magnetic pole with respect to the rotation direction (counterclockwise) of the rotating sleeve 321. A conveying magnetic pole (N2 in this example) and a developing magnetic pole (S1 in this example) are arranged at an interval of approximately 30 ° from (S2) to the downstream side, while an approximately 30 ° interval from the conveying magnetic pole (S2) to the upstream side. The pickup magnetic pole (N1 in this example), the transport magnetic pole (S3 in this example), and the transport magnetic pole (N3 in this example) are arranged.

  As shown in FIG. 1, the developing magnetic pole (S1) faces the electrostatic latent image carrier 21, and the pickup magnetic pole (N1) captures the two-component developer G in the developer containing portion 33. However, the arrangement and number of the respective magnetic poles may be appropriately selected, while the rotating sleeve 321 rotates counterclockwise and the developing magnetic pole (S1) of the magnetic pole roll 322 is provided. In the developing unit, it faces the electrostatic latent image carrier 21.

  Further, the developer accommodating portion 33 has a space for accommodating the two-component developer G, and a developer agitating member in a portion of the developer accommodating portion 33 that is close to (or in contact with) the developer carrier 32. 36 is rotatably arranged along the clockwise direction. Further, the bottom shape of the developer container 33 has a curved shape along the developer carrier 32 and the developer agitating member 36, and a predetermined interval is provided between the developer carrier 32 and the developer agitating member 36. The developer transport path is secured.

  As the developer agitating member 36, as shown in FIG. 3, for example, a member in which a plate-like member 362 is fixed in a cross shape on the outer periphery of the rotating shaft 361 is used. The two-component developer G stirred by the developer stirring member 36 is captured in the vicinity of the pickup magnetic pole (N1) of the developer carrier 32 and is carried and conveyed by the rotation of the rotating sleeve 321 of the developer carrier 32. It has become.

  Further, as shown in FIG. 1, the toner storage portion 35 has a toner stirring member 351 for stirring and transporting the stored toner T. The toner stirring member 351 is, for example, attached to the rotating body 352. An elastic film 353 is attached, and the toner T is swept out along the bottom wall surface of the toner storage portion 35. Further, the bottom shape of the toner accommodating portion 35 has a curved shape along the movement rotation locus of the toner agitating member 351, and the connecting portion between the developer accommodating portion 33 and the toner accommodating portion 35 is provided with toner. A supply path 37 is provided, and the lower end edge of the toner supply path 37 is set slightly higher than the center position of the developer stirring member 36. On the other hand, a protrusion 38 is formed at the upper edge of the toner supply path 37 so as to protrude from the upper edge toward the developer stirring member 36, and the protrusion 38 extends from the toner container 35. A passage for guiding the toner T to the developer accommodating portion 33 is formed.

  In this embodiment, the developer accommodating portion 33 and the developer retracting portion 34 are separated by the developer separating member 39. For example, as shown in FIG. 4, the developer separating member 39 is a plate-like member formed with a width substantially the same as that of the developer carrying member 32. The developer separating member 39 is composed of the developer carrying member. It is inclined and arranged obliquely downward so that the 32 side is the upper side and the opposite side is the lower side. The developer separating member 39 includes an inclined portion 391 disposed in an inclined state, and a lower end portion 392 integrally formed on the lower end portion of the inclined portion 391 downward in the vertical direction. . The upper end 393 of the developer separating member 39 located on the developer carrier 32 side is directly above the transport magnetic pole (N2) in the developer carrier 32 or the transport magnetic pole (N2) as shown in FIG. ) To the upstream side of the developer conveyance direction (clockwise direction side), the surface of the developer carrying member 32 is opposed at a position of several hundred μm to several mm. On the other hand, a lower end 394 opposite to the upper end 393 protrudes downward in the vertical direction in the vicinity of the protrusion 38 described above. Note that the inclination angle of the inclined portion 391 may be arbitrarily set. Further, the end surface of the upper end 393 of the developer separating member 39 is formed to have an end surface along the horizontal direction H0, and the end surface of the lower end 394 is inclined substantially parallel to the left side surface of the protruding portion 38. It is formed to have an end face.

  Further, between the lower end portion 392 and the protruding portion 38 of the developer separating member 39 and between the upper end 393 of the developer separating member 39 and the developer carrier 32, the developer retracting portion 34 and the developer accommodating portion are provided. A circulation path 40 communicating with the portion 33 is formed. In this circulation path 40, for example, the two-component developer G in the developer accommodating portion 33 flows into the developer retracting portion 34 from the inclined portion 391 side, and the inflowed two-component developer G is developed from the lower end portion 392 side. This is a path that flows out to the medicine container 33.

  Further, in this embodiment, the conveyance magnetic pole (N2) and the development magnetic pole (S1) are located at the downstream side (counterclockwise direction side) in the developer conveyance direction from the conveyance magnetic pole (N2) in the developer carrier 32. Between them, a damming portion 41 is disposed so as to face the developer carrier 32. This damming portion 41 has substantially the same width as the developer carrier 32, one end thereof is supported by the development housing 31, and the tip portion thereof is spaced from the developer carrier 32 by a gap of several tens to several hundreds of μm. It is close.

  In this embodiment, since a large amount of the two-component developer G is supplied to the damming portion 41, the gap between the upper end portion 39b of the developer separating member 39 and the developer carrier 32 is different from that of the damming portion 41. It is set wider than the gap with the developer carrier 32.

  In this embodiment, the damming portion 41 also functions as a layer thickness regulating function for regulating the layer thickness of the two-component developer G carried and conveyed by the developer carrier 32. What is the eyebrow thickness regulating function? You may make another. In this case, for example, a mode in which the layer thickness regulating member 42 is provided between the damming portion 41 and the developing magnetic pole (Sl) can be mentioned.

  By the way, in this embodiment, a plurality of partition members that suppress the movement of the two-component developer along the axial direction of the developer carrying member are orthogonal to the developer carrying member at least in the developer retracting portion. It is comprised so that it may provide.

  That is, on the upper surface of the developer separating member 39, as shown in FIGS. 1 and 6, a plurality of partition plates 42 are spaced along the axial direction of the developer carrier 32 at a predetermined (constant in the illustrated example) interval. It is projecting at. The partition plate 42 includes an upper end portion 421 corresponding to the upper end portion 393 of the developer separating member 39, an inclined portion 422 corresponding to the inclined portion 391 of the developer separating member 39, and a lower end portion 392 of the developer separating member 39. A corresponding lower end 423 and a lower end 424 corresponding to the lower end 394 of the developer separating member 39 are provided. The upper end 421 of the partition plate 42 is horizontally formed along the upper end 393 of the developer separating member 39, and the back surface 425 of the lower end 424 of the partition plate 42 is the lower end of the developer separating member 39. It is formed vertically along the back surface 395 of 394. Further, the inclined portion 422 of the partition plate 42 is formed at a predetermined height on the surface of the upper inclined portion 391 of the developer separating member 39, and the lower end portion 423 of the partition plate 42 is also formed of the developer separating member 39. It is formed at a predetermined height along the surface of the lower end portion 292. The lower end 424 of the partition plate 42 is formed in a shape along the left slope of the protruding portion 38, and the lower end 424 of the partition plate 42 is formed so as to contact the left slope of the protruding portion 38. Also good.

  The number and interval of the partition plates 42 can be set as appropriate. However, if the number is too large, the smooth flow of the two-component developer G may be prevented. .

  With the above configuration, the developing device according to the present embodiment is a case where the developing device and the image forming apparatus on which the developing device is mounted are arranged inclined with respect to the horizontal direction as follows. However, it is possible to maintain a good image quality by autonomously correcting the deviation of the developer distribution and suppressing the fluctuation of the toner density.

  That is, in the developing device 24 according to this embodiment, as shown in FIG. 1, the two-component developer G accommodated in the developer accommodating portion 33 is stirred by the developer agitating member 36, and the developer carrying member. Captured by a pick-up pole (Nl) in 32. Thereafter, the two-component developer G that has been captured is subjected to the developer carrier 32 (rotating sleeve 321) by the magnetic attraction force of the pickup magnetic pole (N1) and the transport magnetic pole (S2) and the frictional force between the surface of the developer carrier 32. ) In the rotation direction. The transported two-component developer G, when it reaches the vicinity of the stop part 41, to form the bristles by the conveying pole (N2). Further, the rising of the two-component developer G is regulated by the damming portion 41, so that the developer layer is formed on the developer carrier 32, and the developer layer is formed on the electrostatic latent image carrier. 21 is conveyed to a developing area facing 21. Further, the developer layer of the two-component developer G transported to the development area forms a magnetic brush by the magnetic attraction force of the developing magnetic pole (S1), and the toner T in the two-component developer G forming this magnetic brush is The electrostatic latent image on the electrostatic latent image carrier 21 is visualized by a developing electric field formed between the electrostatic latent image carrier 21 and the developer carrier 32.

  Next, the behavior of the two-component developer G in the vicinity of the damming portion 41 will be described.

  First, in FIG. 1, it is assumed that the toner density of the two-component developer G carried and conveyed by the developer carrier 32 is low. Since the two-component developer G has a large proportion of the magnetic carrier in a unit volume, the apparent magnetic permeability of the developer is increased.

  That is, since the large magnetic attraction force experienced by the two-component developer G from (N2 in this example) the external magnetic field, the two-component developer G low toner concentration is reliably conveyed to the vicinity of stop part 41. The two-component developer G reliably transported to the damming portion 41 pushes out the staying developer staying in the vicinity of the damming portion 41 by the damming force of the damming portion 41 and the magnetic restraining force of the conveying magnetic pole (N2). As shown in FIG. 7, the pushed-out staying developer becomes a falling developer and falls onto the developer separation member 39, passes through the developer retracting portion 34, and then returns to the developer accommodating portion 33 again. .

  At this time, when the two-component developer G having a low toner concentration is led to the developer retracting portion 34 as described above, a space is made in the developer accommodating portion 33 accordingly. As a result, the two-component developer G that has been in the toner supply path 37 from the toner supply port 37a to the developer accommodating portion 33 is caused by the conveying force of the developer agitating member 36 and the weight of the two-component developer G. As a result, the toner supply port 37 a receives the toner T from the toner storage unit 35, and the toner T is quickly supplied to the developer storage unit 33 through the toner supply path 37.

  On the other hand, assuming that the toner density of the two-component developer G carried and conveyed by the developer carrier 32 is high, the two-component developer G has a small proportion of magnetic carrier in a unit volume. The apparent permeability of becomes low. That is, since the magnetic attractive force received by the two-component developer G from the external magnetic field (N2 in this example) is small, most of the two-component developer G having a high toner concentration is developed with respect to the rotation direction of the developer carrier 32. It will fall at a position upstream of the tip of the agent separating member 39. As a result, the two-component developer G does not reach the staying developer staying in the vicinity of the damming portion 41 and does not fall on the developer separating member 39.

  Therefore, the two-component developer G does not fall on the developer separation member 39 but falls at a position upstream of the upper end portion 39b of the developer separation member 39 with respect to the rotation direction of the developer carrier 32. Then, the process returns directly to the developer container 33. At this time, unlike the case where the toner concentration is low, the toner supply path 37 is blocked by the two-component developer G without creating a space in the developer accommodating portion 33. The toner T is not supplied from the storage unit 35.

  As described above, the toner replenishment mechanism according to the present embodiment uses the change in magnetic attraction force in addition to the change in fluidity and bulk of the two-component developer G according to the toner concentration. The toner is supplied to the low two-component developer G, and the toner is not supplied to the two-component developer G having a high toner concentration. When the toner density is low, the two-component developer G is temporarily guided to the developer retracting portion 34, and the bulk change of the two-component developer G in the developer containing portion 33 is emphasized. Accordingly, the two-component developer G in the developer container 33 can quickly take in the toner T in the toner container 35, and can cope with continuous output of high-density images.

  By the way, the developing device 24 according to this embodiment is used with the image forming apparatus on which the developing device 24 is mounted being inclined along the longitudinal direction of the developing device 24 with respect to the horizontal direction. There is a case. Then, the two-component developer G in the developing device 24 is also accommodated in the developer accommodating portion 33 in a state of being inclined with the inclination of the image forming apparatus.

  Now, in FIG. 1, consider a case where the front side of the developing device 24 is high and the back side of the developing device 24 is low. When the toner concentration in the developer accommodating portion 33 decreases, the two-component developer G flows on the developer separating member 39 and falls into the developer accommodating portion 33.

  In this case, the two-component developer G flowing on the developer separating member 39 tends to be biased toward the lower side of the developing device 24 as shown in FIG. As shown in FIG. 9, a plurality of partition plates 42 are provided on the upper surface of the member 39 at a predetermined interval. Therefore, the two-component developer G that tends to flow toward the relatively lower back side of the developing device 24 is blocked by the partition plate 42 and is prevented from flowing unevenly over the interval of the partition plate 42. The

  For example, the bias of the two-component developer G flowing between the adjacent partition plates 42a and 42b and between the partition plates 42b and 42c is shown in FIG. The two-component developer G can be prevented from being biased toward the back side of the developing device 24 by being blocked by 42c.

  Therefore, in the developing device 24, even when the developing device 24 is disposed in a state of being inclined along the longitudinal direction, the two-component developer G is circulated biased toward one end side of the developing device 24. Therefore, the toner concentration in the two-component developer G can be maintained substantially constant along the longitudinal direction of the developing device 24.

  In addition, as described above, the two-component developer G can be prevented from being circulated biased toward one end of the developing device 24, so that the amount of the two-component developer G in the developer container 33 is consumed by the development. Therefore, even if the toner is supplied from the toner container 35 to the toner supply port 37, the toner density can be prevented from becoming nonuniform along the longitudinal direction of the developing device 24. As a result, defects in image quality can also be suppressed.

  Contrary to the above, even when the near side of the developing device 24 is low and the deep side of the developing device 24 is set high, the two-component developer G can be prevented from shifting by the same action.

As described above, in the developing device 24 according to the first embodiment, even when the image forming apparatus on which the developing device 24 is mounted is inclined with respect to the horizontal direction, the developer distribution is reduced. It is possible to maintain a good image quality by autonomously correcting the bias and suppressing fluctuations in toner density.
<Embodiment 2>

  FIG. 10 shows a second embodiment of the present invention. The same parts as those of the first embodiment are described with the same reference numerals. In the second embodiment, the developer stirring member is A plurality of partition members are provided so as to be orthogonal to the developer carrier.

  That is, in the second embodiment, as shown in FIG. 10, the developer stirring member 36 is configured to be provided with a plurality of partition portions 43, and the plurality of partition portions 43 are formed of the developer stirring member 36. And provided so as to be orthogonal to the longitudinal direction of the developer carrier 32. The shape and number of the partition portions 43 and the pitch between the partition portions 43 can be arbitrarily set.

  As described above, according to the second embodiment, even when the developing device 24 is high on the near side and the developing device 24 is on the low side, the developer carrying member 36 is stirred while being stirred by the developer stirring member 36. The two-component developer G supplied to the body 32 tends to move obliquely as shown in FIG. 12, but is blocked as shown in FIG. 13 by the partition 43 provided in the developer stirring member 36. It is stopped and it is prevented that it moves unbalanced over the interval of the partition part 43.

  For example, as shown in FIG. 13, the bias of the two-component developer G that tries to move obliquely between the adjacent partition portions 43a and 43b and between the partition portions 43b and 43c is divided as shown in FIG. It is blocked by the portions 43a, 43b, and 43c, and the two-component developer G can be prevented from moving toward the back side of the developing device 24.

  Therefore, in the developing device 24, even when the developing device 24 is disposed in a state of being inclined along the longitudinal direction, the two-component developer G is not allowed to move toward the one end side of the developing device 24. In combination with the partition plate 42 of the first embodiment, the toner concentration in the two-component developer G can be kept more constant along the longitudinal direction of the developing device 24. Become.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

Contrary to the above, even when the front side of the developing device 24 is low and the deep side of the developing device 24 is set high, the bias of the two-component developer G can be suppressed by the same action.
<Embodiment 3>

  FIG. 14 shows a third embodiment of the present invention. The same reference numerals are given to the same portions as those in the first embodiment. In the third embodiment, in the developer accommodating portion, FIG. A plurality of partition members are provided so as to be orthogonal to the developer carrier.

  That is, in the third embodiment, as shown in FIG. 14, a partition plate 44 provided perpendicularly to the developer carrier 32 is provided in the developer accommodating portion 33 so that the shaft of the developer carrier 32 is provided. It is comprised so that two or more may be arrange | positioned along a direction. The plurality of partition plates 44 are formed integrally with the developer separating member 39 and the partition plate 42. The plurality of partition plates 44 are provided in the developer container 33 so as to set a predetermined gap with respect to the outer periphery of the developer carrier 32 and the outer periphery of the developer agitating member 36. It is arranged on the back side. The shape, the number of the partition plates 44, and the pitch between partitions can be arbitrarily set.

  According to the third embodiment, when the developing device 24 shown in FIG. 14 is installed with an inclination along the longitudinal direction of the developing device 24, for example, the front side of the developing device 24 in FIG. When the back side of the developing device 24 is set low, the two-component developer G flowing through the developer containing portion 33 tends to be biased toward the back side of the developing device 24 as shown in FIG. Therefore, the bias of the two-component developer G is blocked by the partition plate 44 as shown in FIG. For example, the bias of the two-component developer G flowing between the adjacent partition plates 44a and 44b and between the partition plate 44b and the partition plate 44c, as shown in FIG. It is blocked by 44c, and the deviation of the two-component developer G toward the back side can be suppressed. Further, even when the front side of the developing device 24 shown in FIG. 14 is low and the back side of the developing device 24 is installed high, the two-component developer G can be prevented from being shifted by the same action.

Thus, according to the third embodiment, as shown in FIG. 17, by suppressing the bias of the two-component developer G flowing in the vicinity of the developer stirring member 36, the developer is conveyed to the developer carrier 32. It is possible to suppress a phenomenon in which the two-component developer G flowing on the inclined portion 391 of the developer separating means 39 via the circulation path 40 and flowing into the toner supply port 37 is biased to one side in the longitudinal direction of the developing device 24. In this case, even if the toner T is supplied from the toner container 35 to the toner supply port 37, it is possible to prevent the toner concentration from becoming non-uniform along the longitudinal direction of the developing device 24. In addition, problems on the image can be suppressed.
<Embodiment 4>

  FIG. 18 shows a developer separating member and a partition plate according to Embodiment 4 of the present invention. The same parts as those in Embodiment 1 are described with the same reference numerals. 4, the plurality of movable partition plates 46 supported by the rotation shaft 46 o having torsional rigidity are inclined so that the developer partition member 39 can rotate within a predetermined range with respect to the surface of the inclined portion 391 of the developer partition member 39. Projections are provided at predetermined intervals along the axial direction of the developer carrier 32 so as to be orthogonal to the surface of the portion 391. The movable partition plate 46 has a substantially trapezoidal shape, and corresponds to the upper end edge 461 corresponding to the upper end edge 393 of the developer separating member 39, the inclined portion 462 corresponding to the inclined portion 391, and the lower end edge of the inclined portion 391. A lower edge 463 is provided. In the horizontal installation state of the developing device 24 (see FIG. 10), the movable partition plate 46 is substantially orthogonal to the axial direction of the developer carrier 32 and the center of gravity is above the rotation shaft 46o. It is formed and arranged so that Further, the rotation shaft 46o that pivotally supports the movable partition plate 46 has a surface of the inclined portion 391 of the movable partition plate 46 as the developing device 24 is inclined in the longitudinal direction (the axial direction of the developer carrier 32). Can be rotated within a predetermined range (for example, the partition plate 46 is less than ± 90 ° around the rotation shaft 46o from the reference position orthogonal to the axial direction of the developer carrying member 32) and is inclined in the axial direction. For example, it is formed of a torsion spring having a torsional rigidity that enables the partition plate 46 to be restored to the reference position when it is restored to the horizontal state. By using the rotating shaft 46o having such a torsional rigidity, when the developing device 24 is inclined in the longitudinal direction, the movable partition plate 46 is excessively rotated (rotated 90 ° or more from the reference position), and the inclined portion The flow of the two-component developer G on 391 is prevented from being guided to the lower side of the inclination, and the partition plate 46 can be quickly returned to the reference position when the inclination is restored.

  In the developing device according to the present embodiment configured as described above, when the developing device is tilted in the longitudinal direction (axial direction), the developer separation member 39 has an upper surface on the inclined portion 391. It is possible to more effectively prevent the two-component developer G flowing in the direction of slanting and flowing down toward the inclined lower side.

  That is, since the fixed partition plates 42, 43 and the like of the developer separating member 39 according to the previous embodiment are all fixedly disposed on the developer separating member 39 at a predetermined interval, at least the gap between the fixed partition plates. As for the minute component, the two-component developer G flowing on the inclined portion 391 cannot be prevented from flowing down toward the inclined lower side.

  This is because the inclination of the developing device 24 in the axial direction is not temporary. For example, when the device 24 is installed with a constant inclination in the axial direction, after the corresponding installation period has elapsed, There is a possibility that the bias of the two-component developer G that cannot be ignored occurs. Then, when such a non-negligible bias of the two-component developer G occurs in the axial direction of the developing device 24, as described above, toner replenishment becomes excessive on the side where the developer is reduced, and the inside of the developing device 24 is increased. The toner density becomes non-uniform in the axial direction, and there is a possibility that phenomena such as non-uniform image density and fogging occur.

  Therefore, in the developing device according to the present embodiment, when the developing device 24, that is, the developer separating member 39 is inclined in the axial direction, the movable partition plate 46 is rotated around the rotation shaft 46o with respect to the surface of the inclined portion 391. It rotates within a predetermined range on the lower side of the inclination. When the two-component developer G flows on the inclined portion 391 in this inclined state, the flow direction is bent upward by the movable movable partition 46 rotated, and the two-component developer G is further upstream. Led to the side.

  Compared with the fixed partition plate 42 in the previous embodiment, the effect of suppressing the downward bias of the two-component developer G in the present embodiment using this movable partition plate 46 is compared with FIG. Further explanation will be given. FIG. 19 is a diagram illustrating the flow of the two-component developer G in the fixed partition plate 42 and the movable partition plate 46 when the developer separating member 39 is inclined in the axial direction.

  As shown in FIG. 19, when the developing device 24 (see FIG. 10) is inclined in the axial direction, the surface of the inclined portion 391 is formed on the upper end portion of the developer separating member 39 from, for example, the points a to e. The flow of the two-component developer G flowing down is as shown by arrows in the figure. That is, when the fixed partition plate 42 is disposed, the two-component developer G flowing down from each of the points a to e flows down in the vicinity of the point 42P along the side surface of the partition plate 42. On the other hand, when the movable partition plate 46 is disposed, for example, the two-component developer G flowing down from the points a to e is guided to the side surface of the movable partition plate 46 and is upstream from the point 42P. It flows down in the vicinity of the point 46P (in the case of ac) or in the vicinity of the point 46P ′ (in the case of de) on the upstream side. By using the movable partition plate 46 as described above, the two-component developer G that has flowed out to the inclined portion 391 can be returned to the upstream side with a simple configuration, and the developing device 24 is constantly inclined. However, it is possible to more effectively prevent the two-component developer G from being biased downwardly with the inclination in the axial direction.

  Next, a modification of the movable partition plate 46 in the present embodiment will be described with reference to FIG.

  The movable partition plate 46A in this modification has a weight 47 attached to the upper portion of the previous movable partition plate 46, and the center of gravity of the movable partition plate 46A is set to the center of the movable partition plate 46A (in the figure, the longitudinal direction of the movable partition plate 46A). It is moved to the vicinity of the central part. As described above, the rotation shaft 46o is disposed in the vicinity of the central portion in the longitudinal direction of the movable partition plate 46A, so that the lengths of the upper portion 46u and the lower portion 46d of the movable partition plate 46A via the rotation shaft 46o are substantially equal. Thus, the moment applied to the upper part 46u and the lower part 46d of the movable partition plate 46 by the two-component developer G flowing out on the inclined part 391 is balanced, and the rotation angle corresponding to the inclination of the partition plate 46A is stabilized. The two-component developer G flowing down on the inclined portion 391 can be more stably refluxed on the upstream side.

  As described above, according to the developing device according to the fourth embodiment, even when the developing device is continuously used while being inclined in the axial direction, the bias of the two-component developer in the developing device is further reduced. It is possible to effectively suppress the deterioration of the image quality due to the non-uniform toner density in the developing device.

  Of course, the movable partition plates 46 and 46A in the present embodiment are the fixed partition plate 42 and the like in the first to third embodiments described above (the two-component developer G that has flowed out onto the developer separating member 39 is used as the developer. The present invention can be applied by being replaced with a fixed partition plate arranged so as to be guided to the housing portion 33, or can be applied by appropriately combining these embodiments.

1 is a block diagram showing a developing device according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing an image forming apparatus to which the developing device according to Embodiment 1 of the present invention is applied. FIG. 3 is a perspective configuration diagram showing the developer stirring member. FIG. 4 is a perspective configuration diagram showing the developer separating member. FIG. 5 is an enlarged configuration diagram showing the vicinity of the developer carrying member and the developer separating member. FIG. 6 is a perspective view showing the developer separating member and the partition plate. FIG. 7 is an enlarged explanatory view showing the vicinity of the developer carrying member and the developer separating member. FIG. 8 is an explanatory diagram showing the flow of the developer in the conventional developing device. FIG. 9 is an explanatory diagram showing the flow of the developer in the developing device according to Embodiment 1 of the present invention. 10 is a block diagram showing a developing device according to Embodiment 2 of the present invention. FIG. 11 is a perspective configuration diagram illustrating the developer stirring member. FIG. 12 is an explanatory diagram showing the flow of the developer in the conventional developing device. FIG. 13 is an explanatory diagram showing the flow of the developer in the developing device according to Embodiment 2 of the present invention. FIG. 14 is a block diagram showing a developing device according to Embodiment 3 of the present invention. FIG. 15 is a perspective view showing the developer separating member together with the partition plate. FIG. 16 is an explanatory diagram showing the flow of the developer in the conventional developing device. FIG. 17 is an explanatory view showing the flow of the developer in the developing device according to Embodiment 3 of the present invention. FIG. 18 is a perspective view showing a developer separating member and a partition plate according to Embodiment 4 of the present invention. FIG. 19 is an explanatory diagram showing the flow of the developer in the developing device according to Embodiment 4 of the present invention. FIG. 20 is an explanatory view showing the flow of the developer in the developing device according to the modification of the fourth embodiment of the present invention. FIG. 21 is a block diagram showing a conventional developing device.

Explanation of symbols

24: developing device, 32: developer carrier, 33: developer accommodating portion, 34: developer retracting portion, 3
5: toner container, 36: developer stirring member, 39: developer separating member (developer separating means), 42: partition plate, G: two-component developer, 46: movable partition plate.

Claims (5)

A developer carrying body having a magnetic field generating means therein and carrying and carrying a two-component developer containing toner and magnetic carrier, and a developer containing a two-component developer adjacent to the developer carrying body A developer agitating member disposed in a portion of the developer accommodating portion adjacent to the developer carrying member, and a developer carrying member provided through the developer containing portion to supply toner. A toner accommodating portion to be accommodated, and a developer retracting portion which is provided on the downstream side in the developer transport direction of the developer bearing member with respect to the developer accommodating portion adjacent to the developer bearing member and communicates with the developer accommodating portion. A part of the two-component developer that is provided downstream of the developer carrying member in the developer carrying direction with respect to the developer containing portion and the developer retracting portion and carried by the developer carrying member is used as an excess developer. Development based on coughing and toner density Accommodating portion or a developer separating means for separating the surplus developer to the developer saving unit,
In the developing device configured such that the two-component developer separated into the developer retracting portion flows out to the developer accommodating portion or the toner accommodating portion.
A plurality of partition members for suppressing the movement of the two-component developer along the axial direction of the developer carrier are provided at least in the developer retracting portion so as to be orthogonal to the developer carrier. A developing device.   2. The developing device according to claim 1, wherein a plurality of partition members are provided on the developer stirring member so as to be orthogonal to the developer carrier.   3. The developing device according to claim 1, wherein a plurality of partition members are provided in the developer accommodating portion so as to be orthogonal to the developer carrying member.   2. The developing device according to claim 1, wherein the partition member is capable of rotating with an inclination of the developing device in an axial direction, and substantially orthogonal to the developer carrying member with the recovery of the inclination. It is pivotally supported by a rotating shaft having a torsional rigidity so that it can be restored to a position, and is arranged so that the center of gravity of the partition member is above the rotating shaft in a horizontal installation state. A developing device. The developing device according to claim 4, wherein the rotation shaft of the partition member is disposed in the vicinity of a central portion in the longitudinal direction of the partition member.

Images