JP2012137701A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that sets an appropriate housing gap irrespective of variation and thermal deformation generated during the manufacture of the housing, and reduces the amount of floating toner that scatters from an opening without the occurrence of clogging of developer in the housing gap, and an image forming apparatus that includes the developing device to reduce stains on images due to toner ejected to the outside of the developing device.SOLUTION: A developing device includes an opposing surface 601 that is energized toward a developing roller 11, and expands in a direction (T5 direction in Figure 11) that is opposite to the energization direction (T4 direction in Figure 11) despite thermal expansion of a storage part 10 in a high temperature environment, to further compress a compression spring 61. Even if the storage part 10 is deformed and contracted, the opposing surface 601 is energized in the energization direction by the compression spring 61.

Description

  The present invention relates to a developing device that develops a latent image on an image carrier using a developer containing toner, and an image forming apparatus including the developing device.

  Conventionally, in a developing device that develops a latent image on an image carrier using a developer containing toner, the toner in the developer housing is agitated by a supply roller or the like provided in the developer housing that contains the developer. And conveyed to the developing roller. The toner conveyed to the developing roller is supplied from the opening of the developing housing to the latent image on the image carrier provided outside the developing device, and the toner image is developed on the image carrier. The developed toner image is transferred to a sheet as a recording medium at a transfer nip formed on the downstream side in the rotation direction of the image carrier, and a toner image is formed on the sheet.

  In such a developing device, there is a problem in that the floating toner generated by the stirring of the developer in the developing housing is carried by the air flow accompanying the rotation of the image carrier and the developing roller and is ejected as dust from the opening. It has become. This is because floating toner accumulates inside the image forming apparatus provided with the developing device and causes contamination of the paper conveyed during image formation.

  Such floating toner dust is ejected through a gap between the developing roller forming the developing nip portion and the developing housing. Specifically, in the gap on the downstream side in the rotation direction of the developing roller from the opening (hereinafter referred to as a housing gap), an air flow through the opening is likely to occur, and in particular, the developing housing is thermally deformed in a high temperature environment. When the housing gap widens, a large amount is ejected.

  In addition, the dust of floating toner is a problem particularly in a developing type developing device that supplies toner onto a photosensitive member by forming a magnetic brush using a developer containing toner and a carrier. In such a developing device, floating toner is also generated by the jumping or lying down movement of the magnetic brush formed on the developing roller or the like, so that a relatively large amount of floating toner dust is generated. The floating toner is likely to be ejected through a housing gap on the downstream side in the rotation direction of the developing roller from the opening. Particularly, when the charge amount of the developer is reduced by long-term use, the magnetic brush formed on the developing roller As the height of the ear is shortened and the housing gap is widened, a large amount of water is ejected.

  Regarding the prevention of contamination of the recording medium and the like due to the powdery smoke of the floating toner, Patent Document 1 discloses that the case gap between the developer containing case and the developing roller is downstream of the opening in the rotation direction of the developing roller with respect to the opening. A developing device that reduces the scattering of toner by changing the thickness of the case portion forming the case gap in the rotation axis direction of the developing roller and generating a suction airflow at both ends in the width direction of the opening is disclosed. Yes.

  Patent Document 2 discloses a region in which the width of the case gap gradually increases from the entrance to the downstream side in the rotation direction of the developing roller with respect to the case gap between the case housing the developer and the developing roller. A developing device is disclosed that reduces the scattering of toner by forming a case so that and are alternately arranged and generating a suction airflow toward the inside of the case.

JP 2006-145921 A JP 2010-78895 A

  However, the developing devices described in Patent Documents 1 and 2 cannot cope with an increase in the amount of toner scattering that occurs when the case is thermally deformed under a high temperature environment and the case gap is widened.

  Conventionally, the gap of the case gap has been designed in consideration of tolerances in a width that can prevent clogging of the developer in the case gap and retention of the developer, taking into account variations in the case dimensions at the time of manufacture. Has been. Here, the amount of scattering of the floating toner may increase in a developing device that is swung so that the gap between the case gaps is widened due to variations in case dimensions during manufacturing. The developing devices described in Patent Documents 1 and 2 cannot cope with an increase in the amount of floating toner scattered due to such a variation in case dimensions during manufacture.

  The present invention has been made in order to solve the above-described problems, and a developing device capable of setting an appropriate housing gap regardless of variations in housing production or thermal deformation, and thus, A developing device that can reduce the amount of floating toner splashed from the opening without causing clogging of the developer in the housing gap, and the development device to provide a stain on the image due to the toner ejected to the outside of the developing device. It is an object of the present invention to provide an image forming apparatus capable of reducing the above.

  In one aspect of the developing device of the present invention for achieving the above object, the housing is a housing portion that houses a developer, and a housing portion having an opening, and a part of the surface is located outside the housing portion from the opening. A developer carrying member that is exposed and rotates while carrying the developer on the surface; and a regulating unit that is interposed between a rotation shaft of the developer carrying member and an inner wall surface of the containing unit. The inner wall surface located downstream of the opening in the rotation direction of the developer carrying member from the opening is an inner wall that is not immersed in the developer when the developer is accommodated in the accommodating portion up to the maximum accommodation amount. A regulating portion having a facing surface that is at least a part of a wall surface, and a biasing portion that biases the facing portion in a direction in which the facing surface faces the developer carrier. Is a distance between the rotating shaft and the facing surface by contacting the facing portion. Keeping a predetermined length.

  The developing device further includes a magnet body fixedly disposed inside the developer carrier, wherein the developer includes toner and a carrier, and the magnet body is located at a position facing the facing surface. In addition, it has a magnetic pole.

  Furthermore, in the developing device, the restriction portion can change the predetermined length.

  Furthermore, in the developing device, the restricting portion is provided to be rotatable about a rotation shaft of the developer carrying member, and has a cam that contacts the facing portion, and the facing surface is formed by rotation of the cam. The urging portion moves in the direction in which the opposing portion is urged or the direction in which the urging portion urges the opposing portion.

  In order to achieve the above object, one aspect of the image forming apparatus of the present invention is an image forming apparatus that forms an image on a recording medium, and includes the developing device.

  In order to achieve the above object, one aspect of the image forming apparatus of the present invention is an image forming apparatus that forms an image on a recording medium, the developing device, and a drive unit that rotationally drives the regulating unit. A control unit that controls rotation of the regulating unit by the driving unit, and the control unit includes a calculation unit that calculates a cumulative amount of toner consumption in the developing device, and the cumulative consumption The predetermined length is changed based on the amount equivalent amount.

  According to the developing device of the present invention, the fluctuation of the housing gap due to the deformation of the housing portion due to the ambient temperature change is suppressed. Accordingly, it is possible to reduce the ejection of the dust toner due to the change in the housing gap, and it is possible to prevent clogging and retention of the developer.

  Furthermore, according to the developing device of the present invention, when the charge amount of the developer is lowered due to long-term use, the height of the magnetic brush formed on the developing roller is shortened and the case gap is widened. It is possible to reduce the ejection of the dust toner.

  Further, according to the image forming apparatus of the present invention, since the length of the housing gap can be adjusted according to the amount corresponding to the cumulative consumption amount of toner in the developing device, when the charge amount of the developer decreases due to long-term use. It is possible to further reduce the ejection of dust toner generated by shortening the height of the ears of the magnetic brush formed on the developing roller and widening the case gap.

It is a schematic block diagram which shows image forming apparatus GS1 which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the conventional developing device. It is a graph showing the experimental result which shows the relationship between the length of the housing gap in a conventional developing device, and the amount of smoke. It is a graph showing the experimental result which shows the relationship between the length of the housing gap in the conventional image development apparatus, and the temperature in an accommodating part. It is a graph showing the experimental result which shows the relationship between the length of the magnetic brush formed in the housing gap in the conventional developing device, and the number of the recording media which developed. It is a graph showing the experimental result which shows the relationship between the developer conveyance amount in the housing gap in the conventional developing device, and the number of the recording media which developed. It is a graph showing the experimental result which shows the relationship between the amount of developer conveyance in the housing gap in a conventional developing device, and the amount of dust. It is a graph showing the experimental result which shows the relationship between the length of the housing gap in the conventional image development apparatus, and the stain density of the recording medium which developed. It is a schematic sectional drawing which shows the smoke reduction mechanism FTK of developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the smoke reduction mechanism FTK of developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the periphery of the opposing part of developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the periphery of the opposing part of developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the periphery of the opposing part of developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the periphery of the opposing part of developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the periphery of the opposing part of developing device DD1 which concerns on Embodiment 1 of this invention. 3 is a table showing the relationship between the number of images formed by the image forming apparatus GS1 and a predetermined length in the developing device DD1. It is a schematic block diagram which shows developing device DD1 which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows developing device DD1 which concerns on Embodiment 1 of this invention.

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

  FIG. 1 is a schematic configuration diagram showing an image forming apparatus (hereinafter referred to as “image forming apparatus GS1”) according to Embodiment 1 which is an example of the present invention. The image forming apparatus GS1 includes a developing device according to the first embodiment which is an example of the present invention (hereinafter referred to as “developing device DD1”). First, the image forming apparatus GS1 will be described with reference to FIG.

<Image forming apparatus GS1>
The image forming apparatus GS1 includes an automatic document conveying device 40 that conveys a document, an image reading unit 20 that reads an image of the conveyed document at an image reading position and generates image data, and a recording medium storage unit that stores a recording medium S. 300 and a manual feed supply unit 310, and image formation for forming an image by an electrophotographic method on the recording medium S conveyed from the recording medium storage unit 300 or the manual feed supply unit 310 based on the image data generated by the image reading unit 20. Part 50, fixing device 70 located downstream in the recording medium conveyance direction from image forming part 50, and discharge part 810 on which recording medium S on which an image has been formed and discharged is placed.

  Further, the image forming apparatus GS1 includes a control unit 90 that controls each process such as image formation, a memory 91 that stores data necessary for each process, and an operation for a user to input information such as a job related to image formation. A panel 93 and a developing device DD1 detachably attached to the image forming apparatus main body are provided.

  The automatic document feeder 40 includes a document feeding table 41 on which documents are stacked, a document registration unit GRB that transports documents loaded on the document feeding table 41 while controlling the conveyance timing and posture, and an image reading position. A platen roller 42 that transports a document transported from the document registration unit GRB, a document reversal transport unit 44 that reverses the front and back of the document in duplex scanning, and a document discharge tray 43 on which the discharged document is stacked. is doing.

  The image reading unit 20 includes a movable first scanning unit 21 having a lamp and a mirror for illuminating a document, and two mirrors. The second scanning unit 21 is movable at a speed half that of the scanning unit 21. It has a scanning unit 22, a light receiving unit 23 that has a lens and an image sensor and generates an image signal, and a platen glass 24 on which a document is placed.

  The image reading unit 20 can perform reading in a mode for reading a document conveyed by the automatic document conveyance device 40 and a mode for reading a document placed on the platen glass 24.

  The recording medium S loaded on the document feeder 41 is conveyed to the image reading position after the recording medium conveyance timing and the attitude of the recording medium S are controlled in the document registration unit GRB.

  Image information is read from the original conveyed to the image reading position by the scanning unit. The read image information is subjected to image processing necessary for positional deviation correction, and then converted into an electrical image signal for forming an electrostatic latent image by the light receiving unit 23. This image signal is input to the image forming unit 50. Note that the image information may be input to the image forming unit 50 from an external device such as a personal computer (not shown).

  The recording medium storage unit 300 includes storage trays 301a, 301b, and 301c that can be individually inserted into and removed from the main body of the image forming apparatus GS1, and supply rollers 301a and 301b that supply the recording medium S stored in the storage trays 301a, 301b, and 301c. , 301c. The storage trays 301a, 301b, and 301c can store different types of recording media S, respectively. For example, when an image is formed on the recording medium S stored in the storage tray 301a, the supply roller 302a and the retard roller pair rotate according to the image forming operation to separate the recording medium S from the storage tray 301a one by one. It is designed to be transported.

  The manual feed supply unit 310 includes a manual feed tray 311 provided in the image forming apparatus GS1 main body so as to be openable and closable, and a supply roller for supplying the recording medium S stacked on the manual feed tray 311. For example, when an image is formed on the recording medium S stacked on the manual feed tray 311, the supply roller rotates according to the image forming operation, and is separated one by one from the recording medium S stacked on the manual feed tray 311. It is designed to be transported.

  The recording medium S conveyed from the recording medium storage unit 300 or the manual feed tray 311 is conveyed along a recording medium conveyance path provided with a conveyance roller pair, and is conveyed to the image forming unit 50 via the recording medium registration unit SRB. .

  The recording medium registration unit SRB corrects the skew of the recording medium S (conveyance in a state where the recording medium S is inclined with respect to the conveyance direction) and aligns the recording medium S so that there is no inclination in the direction perpendicular to the conveyance direction. The recording medium is transported from the beginning. The recording medium S that has passed through the recording medium registration unit SRB is conveyed to the image forming unit 50 while being guided by the first conveyance guide G1 and the second conveyance guide G2.

  The image forming unit 50 includes an image carrier 51 formed of a rotating drum-shaped photosensitive member, a charging device 52 that charges the image carrier 51, an exposure device 53 that exposes the image carrier 51 based on an image signal, A developing device DD1 that forms a toner image on the image carrier 51 with a developer including toner and carrier; a transfer unit 55 that transfers an image on the image carrier 51 to the recording medium S that has passed through the recording medium resist unit SRB; It has. A charging device 52, an exposure device 53, a developing device DD1, and a transfer unit 55 are arranged in this order along the rotation direction of the image carrier 51 with respect to the outer peripheral surface of the image carrier 51. Further, an image carrier cleaning device 56 including an image carrier cleaning blade is provided at a position downstream of the transfer unit 55.

  The image carrier 51 has a photosensitive layer made of a resin containing an organic photoconductor on the outer peripheral surface of a drum-shaped metal substrate, and is provided to be rotatable in the direction of arrow T1 in FIG. Further, in FIG. 1, the rotation axis is disposed in a direction perpendicular to the paper surface.

  The charging device 52 is, for example, a scorotron charger having a grid electrode and a discharge electrode, and charges the surface of the image carrier 51.

  The exposure device 53 includes a laser irradiation device, and exposes the image carrier 51 by irradiating laser light. The laser beam can be irradiated based on the image signal of the document read at the image reading position.

  The charging device 52 and the exposure device 53 constitute an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier 51.

  Although described in detail later, the developing device DD1 includes a developing roller for supplying toner to the electrostatic latent image formed on the image carrier 51 and developing the electrostatic latent image. A toner image is formed on the image carrier 51 by applying a DC and / or AC bias voltage from the voltage applying means.

  The transfer unit 55 is opposed to the surface of the image carrier 51 and has a transfer roller 551 provided so as to form a transfer nip portion, and a transfer current supply device connected to the transfer member, such as a constant current power source. (Not shown).

  For example, the transfer unit 55 transfers the toner image formed on the image carrier 51 to the recording medium S by supplying a transfer current to the transfer roller 551 by a transfer current supply device (not shown). A contact transfer method can be used. The recording medium on which the toner image is transferred at the transfer nip portion is conveyed to the fixing device 70.

  Note that in order to transfer the image on the image carrier 51 without deviation to the recording medium S that has passed through the recording medium registration unit SRB, the controller 90 controls the conveyance timing of the recording medium S to the transfer nip and the image carrier. The rotation timing of 51 is appropriately controlled.

  Further, when the image is transferred to the recording medium S in the transfer nip portion, for example, the transfer member is transferred by the control unit 90 so that an appropriate transfer current according to the type of the recording medium S conveyed to the transfer nip portion is obtained. The voltage applied to is adjusted.

  The image carrier cleaning device 56 includes, for example, an image carrier cleaning blade. The image carrier cleaning blade is made of, for example, an elastic material such as urethane rubber, and is provided such that its base end portion is supported by a support member and its front end portion is in contact with the surface of the image carrier 51. . The direction extending from the base end side of the image carrier cleaning blade can be a so-called counter direction, which is the direction opposite to the moving direction due to the rotation of the image carrier 51 at the contact portion.

The fixing device 70 includes, for example, a pressure roller 71, a fixing roller 72, and a heating roller 73, and pressurizes and heats the toner image transferred onto the recording medium S to fix it. The recording medium S that has passed through the fixing device 70 is transported along the transport path, and is discharged to a discharge portion 810 outside the image forming apparatus via a discharge roller. Note that when the image on the recording medium S is fixed in the fixing device 70, for example, the control unit is set so that the fixing temperature and the fixing speed are appropriate according to the type of the recording medium S conveyed to the fixing device 70. 90 adjusts the fixing speed and / or the temperature of the heating roller.
<Developing device DD1>
Next, the developing device DD1 will be described in more detail with reference to FIG. 2 and FIG.

  As shown in FIGS. 2 and 3, the developing device DD1 includes a housing portion 10 serving as a developing housing that houses a developer including toner and a carrier for forming an image on the recording medium S, and a magnetic brush by the carrier. The developing roller 11 that rotates while being formed on the surface, supplies toner to the electrostatic latent image formed on the image carrier 51, and the toner and the carrier that are accommodated in the accommodating portion 10 are mixed and stirred. And a conveying roller 12 that frictionally charges the toner and conveys the toner to the developing roller 11.

  The storage unit 10 supplies toner to a storage region 101 filled with a developer (a shaded region in the storage unit in FIG. 2) and an electrostatic latent image formed on the image carrier 51. An opening 102, a smoke reduction mechanism FTK for reducing the smoke of floating toner from the opening 102, and a regulating member 103 for adjusting the length of the magnetic brush formed on the surface of the developing roller 11. I have. Details of the dust reduction mechanism FTK will be described later. Note that the storage unit 10 is provided with a fullness detection sensor (not shown). When the storage area 101 is filled with toner, it is considered that the developer is stored in the developing device DD1.

  The developing roller 11 has a shape extending in one direction, and includes a sleeve 111 that can rotate in the direction of the arrow T2 in FIG. 2 and a plurality of magnetic poles. And a first shaft 113 as a rotation shaft of the sleeve 111. A magnetic brush is formed on the outer peripheral surface of the sleeve 111 by the magnetic poles of the magnet body 112, and the sleeve 111 forming the magnetic brush rotates around the magnet body 112, so that the toner moves on the sleeve 111 along with the rotation. A part of the surface of the sleeve 111 is exposed to the opening 102 and is adjacent to the image carrier 51 in parallel, thereby forming a developing nip portion. The toner conveyed to the developing nip portion as the sleeve 111 rotates rotates the image. The latent image on the carrier 51 is supplied.

  More specifically, the magnet body 112 has a magnetic pole MP1, a magnetic pole MP2, a magnetic pole MP3, a magnetic pole MP4, and a magnetic pole MP5, and each forms a magnetic force distribution indicated by a broken line in FIG. The magnetic pole MP <b> 1 is a magnetic pole for carrying the developer accommodated in the accommodating portion 10 on the sleeve 111, and is provided at a position facing the accommodating region 101. The magnetic pole MP1 acts on the carrier as the magnet body 112, so that the toner is carried on the sleeve 111. The magnetic pole MP <b> 2 is a magnetic pole for conveying the developer carried on the sleeve 111 to the development nip portion, and is provided at a position facing the regulating member 103. A part of the developer carried on the sleeve 111 is scraped off by the regulating member 103 and returned to the storage area 101. The magnetic pole MP3 is a magnetic pole for forming a magnetic brush for supplying toner to the latent image on the image carrier 51 rotating in the direction of arrow T1 in FIG. 2 in the developing nip portion, and the image is passed through the developing nip portion. It is provided at a position facing the carrier 51. The developer that has passed through the regulating member 103 forms a magnetic brush at the position of the magnetic pole MP 3, and the formed magnetic brush rubs against the image carrier 51. At this time, the toner on the carrier is supplied to the latent image on the image carrier 51 by the electric field in the developing nip portion. The magnetic pole MP4 is a magnetic pole for transporting the toner that has passed through the developing nip portion, and is positioned downstream of the opening 102 in the rotation direction of the developing roller 11. The toner that has passed through the developing nip is carried on the magnetic brush formed on the sleeve 111 by the magnetic force of the magnetic pole MP4, and is conveyed in the direction toward the magnetic pole MP5 as the magnetic brush moves as the sleeve 111 rotates. The The magnetic pole MP5 is a magnetic pole for causing the toner conveyed by the magnetic pole MP4 to be peeled off toward the containing area 101, and is located downstream of the magnetic pole MP4 in the rotation direction of the developing roller 11. The toner is released from the sleeve 111 by the repulsive force generated between the magnetic pole MP5 and the magnetic pole MP1 located downstream of the magnetic pole MP5 in the rotation direction of the developing roller 11. Here, the polarity of the magnetic pole MP5 and the polarity of the magnetic pole MP1 are the same. The toner released from the sleeve 111 is returned to the storage area 101 again. The plurality of magnetic poles provided with the magnet body 112 are not limited to the magnetic pole MP1, the magnetic pole MP2, the magnetic pole MP3, the magnetic pole MP4, and the magnetic pole MP5. For example, the number of magnetic poles may be smaller or larger.

  The developing roller 11 is made of a material having a higher thermal deformation temperature (a deflection temperature under load) than the facing portion 60 of the smoke reduction mechanism FTK, which will be described in detail later. For example, the surface-treated aluminum or the like is used. A conductive roller made of a metal material can be used. Further, as the developing roller 11, a coating material such as resin or rubber coated on the outer peripheral surface of a conductive substrate such as aluminum may be used. In this case, as a coating material, for example, polyester resin, polycarbonate resin, acrylic resin, polyethylene resin, polypropylene resin, urethane resin, polyamide resin, polyimide resin, polysulfone resin, polyether ketone resin, vinyl chloride resin, vinyl acetate resin, A resin such as a silicone resin or a fluorine resin, or a rubber such as silicone rubber, urethane rubber, nitrile rubber, natural rubber, or isoprene rubber can be used.

The conveyance roller 12 has a shape extending in one direction, is disposed so as to be adjacent to the developing roller 11 in parallel, and is provided to be rotatable in the same direction as the rotation direction of the developing roller 11.
The transport roller 12 has a second shaft 121 as a rotation shaft, and frictionally charges the toner in the storage region 101 by mixing and stirring the developer in the storage region 101, and at the position of the magnetic pole MP1. The developer is wound up toward the outer peripheral surface of a certain sleeve 111. The developer wound up by the transport roller 12 is carried on the outer peripheral surface of the sleeve 111 at the position of the magnetic pole MP1. Here, “parallel” is a concept including substantially parallel. Further, the rotation direction of the transport roller 12 is not particularly limited, and the conveyance roller 12 may be configured to rotate in a direction opposite to the rotation direction of the developing roller 11.

  The developing device DD1 has an attachment / detachment detection unit (not shown) for detecting attachment / detachment to / from the main body of the image forming apparatus GS1 on the end side of the outer wall of the housing unit 10, and the non-installation of the main body of the image forming apparatus GS1. By opening and closing the illustrated main body cover, it can be attached to and detached from the image forming apparatus GS1.

  The control unit 90 can determine that the developing device DD1 is attached to the image forming apparatus GS1 body when the attachment detection sensor (not shown) provided on the image forming apparatus GS1 body side detects the attachment / detachment detection unit. . More specifically, the mounting detection sensor is a photoelectric sensor having a light projecting unit and a light receiving unit, and when the developing device DD1 is set in the main body of the image forming apparatus GS1, the attachment / detachment detecting unit is a light projecting unit. It is determined that the developing device DD1 is attached to the main body of the image forming apparatus GS1 by shielding light from the light receiving unit. The mounting detection sensor is not limited to a photoelectric sensor, and a known sensor such as a contact displacement sensor can be used.

  Further, the developer including the toner and the carrier used in the developing device DD1 is not particularly limited, and a commonly used known developer can be used.

  Here, as the toner, a colorant in the binder resin, and if necessary, a charge control agent, a release agent, etc., which are treated with external additives can be used. Although not particularly limited, those of about 3 to 15 μm are desirable.

  And in manufacturing such a toner, it can manufacture by the well-known method generally used, for example, it can manufacture using a pulverization method, an emulsion polymerization method, a suspension polymerization method etc.

  In addition, as the binder resin used for the toner, a publicly known resin can be used. For example, a styrene resin (monopolymer or copolymer containing styrene or a styrene substitution product), a polyester resin, Epoxy resins, vinyl chloride resins, phenol resins, polyethylene resins, polypropylene resins, polyurethane resins, silicone resins, and the like can be used, but are not limited to these. These resins can be used as a single substance or a composite, and those having a softening temperature in the range of 80 to 160 ° C. and those having a glass transition point in the range of 50 to 75 ° C. are preferably used.

  Further, as the above-mentioned colorant, publicly known publicly known ones can be used. For example, carbon black, aniline black, activated carbon, magnetite, benzine yellow, permanent yellow, naphthol yellow, phthalocyanine blue, first sky blue Ultramarine Blue, Rose Bengal, Lakey Red, etc. can be used, and it is generally preferable to use 2-20 parts by weight with respect to 100 parts by weight of the binder resin.

  Also, known charge control agents can be used. Examples of charge control materials for positively chargeable toners include nigrosine dyes, quaternary ammonium salt compounds, triphenylmethane compounds, Imidazole compounds, polyamine resins, and the like can be used, and charge control materials for negatively chargeable toners include metal-containing azo dyes such as Cr, Co, Al, and Fe, salicylic acid metal compounds, alkyl salicylic acid metal compounds, calixes. An arene compound or the like can be used. In general, such a charge control agent is preferably used at a ratio of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  In addition, as the above-mentioned mold release agent, known ones that are generally used can be used. For example, polyethylene, polypropylene, carnauba wax, sazol wax and the like can be used alone or in combination of two or more. In general, it is preferably used at a ratio of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  Further, as the particles externally added to the toner, commonly used known particles can be used, and for example, silica, titanium oxide, aluminum oxide or the like is used as a fluidizing agent for improving the fluidity of the toner. In particular, it is preferable to use a silane coupling agent, a titanium coupling agent, a silicone oil or the like made water repellent. Such a fluidizing agent is added at a ratio of 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner. The number average primary particle size of the fluidizing agent is preferably 10 to 100 nm.

  Further, as the carrier, a known carrier that is generally used can be used, and a binder-type carrier, a coat-type carrier, or the like can be used. The particle size of this carrier is not particularly limited, but is 15 to 100 μm. Is preferred.

  Here, the binder type carrier is one in which magnetic fine particles are dispersed in a binder resin, and positive or negative chargeable fine particles are fixed to the carrier surface or a surface coating layer is provided. You can also. Further, the charging characteristics such as the charging polarity of the binder type carrier can be controlled by the type of the binder resin material, the chargeable fine particles, and the surface coating layer.

  And as binder resin used for this binder type carrier, thermoplastic resin, such as vinyl resin represented by polystyrene resin, polyester resin, nylon resin, polyolefin resin, thermosetting properties, such as phenol resin, for example Resin can be used.

  Magnetic fine particles used for the binder type carrier include spinel ferrite such as magnetite and gamma iron oxide, spinel ferrite containing one or more metals other than iron (Mn, Ni, Mg, Cu, etc.), and barium ferrite. Magneto-plumbite type ferrite such as iron, iron or alloy particles having iron oxide on the surface can be used, and the shape thereof may be any of granular, spherical and acicular.

  In particular, when high magnetization is required for the binder type carrier, it is preferable to use iron-based ferromagnetic fine particles. In consideration of the chemical stability of the binder type carrier, it is preferable to use ferromagnetic fine particles of magnetoplumbite type ferrite such as spinel ferrite and barium ferrite containing magnetite and gamma iron oxide. And the binder type | mold carrier which has desired magnetization can be obtained by selecting the kind and content of a ferromagnetic fine particle suitably. The magnetic fine particles are suitably added in an amount of 50 to 90% by weight in the binder type carrier.

  Moreover, as a material of said surface coating layer in a binder type | mold carrier, a silicone resin, an acrylic resin, an epoxy resin, a fluorine resin etc. are used, for example, these resin is coated on the surface, and it hardens | cures and forms a coating layer By doing so, the charge imparting ability can be improved.

  Further, in fixing the chargeable fine particles or the conductive fine particles to the surface of the binder type carrier, for example, after the binder type carrier and these fine particles are uniformly mixed and adhered to the surface of the binder type carrier. By applying mechanical and thermal impact force, these fine particles can be fixed by being driven into a binder type carrier. In this case, these fine particles are not completely embedded in the binder type carrier, but are fixed so as to protrude from the surface of the binder type carrier.

  Here, as the chargeable fine particles, organic or inorganic insulating materials can be used. Specifically, organic insulating materials such as polystyrene, styrene copolymers, acrylic resins, various acrylic copolymers, nylon, polyethylene, polypropylene, fluororesins, and cross-linked products thereof, for example. Fine particles can be used. Regarding the charge level and polarity, a desired level of charge and polarity can be obtained by a material, a polymerization catalyst, a surface treatment, and the like. As the inorganic insulating material, for example, negatively charged inorganic fine particles such as silica and titanium dioxide, and positively charged inorganic fine particles such as strontium titanate and alumina can be used.

  In addition, the above-mentioned coated carrier is a carrier in which a resin coat layer is provided on the surface of carrier core particles made of a magnetic material. In this coated carrier, as in the binder-type carrier, Alternatively, negatively chargeable fine particles can be fixed.

  The charging characteristics such as polarity of the coat type carrier can be controlled by the type of the resin coat layer and the chargeable fine particles, and the same material as the binder type carrier can be used. In particular, a resin similar to the binder resin of the binder type carrier can be used for the resin of the resin coat layer.

  The mixing ratio of the toner and the carrier may be adjusted so as to obtain a desired toner charge amount, and the ratio of the toner to the total amount of the toner and the carrier is 3 to 50% by weight, preferably 6 to 6%. 30% by weight is suitable.

<Powder reduction mechanism FTK>
Next, the smoke reduction mechanism FTK of the developing device DD1 will be described with reference to FIGS. In addition, the scale of the structural member in each drawing does not necessarily correspond with an actual scale.

  First, floating toner dust generated in a conventional developing device will be described with reference to FIG. As described above, in the conventional developing device, the gap between the developing roller 11 forming the developing nip portion and the accommodating portion 10, which is the housing gap of the gap on the downstream side in the rotation direction of the developing roller 11 from the opening 102. Through the HG, in particular, a large amount of dust is ejected.

  Specifically, during development, the image carrier 51 rotates in the T1 direction and the developing roller 11 rotates in the T2 direction. In other words, the developing roller 11 and the image carrier 51 rotate in opposite directions. In the housing gap HG on the downstream side in the rotation direction of the developing roller 11 from the opening 102, an air flow (in the direction of the arrow T3 in FIG. 4) that passes through the opening 102 is likely to be generated, and dust is ejected on the air flow.

  Here, the housing gap HG is a substantial gap between the outer peripheral surface of the sleeve 111 of the developing roller 11 and the inner wall surface of the accommodating portion 10. For example, a magnetic brush is formed on the developing roller 11. In the developing type developing device that supplies toner onto the image carrier 51, the housing gap HG is a gap between the end of the brush head of the magnetic brush formed on the sleeve 111 and the inner wall surface of the housing portion 10. It is. Further, in a one-component developing device that carries toner on the developing roller 11, the gap is between the toner carried on the developing roller 11 and the inner wall surface of the storage unit 10.

  Further, in the conventional developing device, taking into account the dimensional variation at the time of manufacture of the housing portion 10, there is a housing gap HG in order to prevent clogging of the developer in the housing gap HG and retention of the developer. It was set wider. For example, when the width of the housing gap HG becomes smaller than 0.6 mm, the developer stays in the housing gap HG. When the width becomes smaller than 0.5 mm, the developer is clogged in the housing gap HG. Occurs. Based on these considerations, the housing portion 10 is designed and the developing roller 11 is positioned so that the housing gap HG is 1.6 ± 0.5 mm. As described above, the tolerance of the housing gap HG prevents clogging of the developer and the retention of the developer in the housing gap HG even when the dimensional variation of the accommodating portion 10 is swung in the direction in which the housing gap HG narrows. Was set to be.

  Here, FIG. 5 shows a result of measuring the amount of dust toner ejected from the developing device with a dust measuring device (particle counter) with respect to the change in the length of the housing gap HG. As shown in FIG. 5, it can be seen that the amount of dust toner ejected increases as the housing gap HG becomes wider. Further, for example, when the housing portion 10 is made of a resin material such as ABS (acrylonitrile-butadiene-styrene resin), as shown in FIG. 6, the developing housing is thermally deformed due to a change in ambient temperature, and the housing When the gap HG is widened, a large amount of dust toner is ejected.

  FIG. 7 shows the result of measuring the height of the magnetic brush formed on the developing roller 11 constituting the housing gap HG with respect to the change in the number of image formations in the image forming apparatus including the developing device, that is, the change in durability. Shown in FIG. 8 shows the result of measuring the change in the developer conveyance amount (toner conveyance amount) of the developing roller 11 with respect to the durability change. Further, FIG. 9 shows the result of measuring the amount of dust toner ejected from the developing device with respect to the change in the developer conveyance amount of the developing roller 11.

  As shown in FIG. 7 to FIG. 9, the developer charge amount decreases due to the durability of the developer. In other words, the length of the magnetic brush formed by the durability of the developer is shortened and the housing gap HG is widened. It can be seen that the amount of the dust toner ejected increases as the time goes on. FIG. 10 shows the result of measuring the contamination of the recording medium S caused by the dust accumulated in the first conveyance guide G1 and the second conveyance guide G2 with respect to the change in the length of the housing gap HG. As shown in FIG. 10, it can be seen that the contamination of the recording medium S worsens as the housing gap HG becomes wider.

  From the above experimental results, the conventional developing device, particularly when the dimensional variation of the accommodating portion 10 is swung in the direction in which the housing gap HG widens, causes a large amount of powder smoke to be ejected, and the quality between the developing devices. It can be seen that there is also a problem in terms of securing.

  As described above, the amount of dust toner ejected from the developing device is largely attributable to the width of the housing gap HG. The housing portion 10 is designed so that the housing gap HG becomes narrow, and the developing roller 11 is positioned. It is considered effective to reduce the ejection amount of the dust toner. However, if the housing gap HG is too narrow, the developer gap in the housing gap HG and the developer stagnation may occur. Therefore, it is necessary to set the length of the housing gap HG in consideration of the dimensional variation at the time of manufacturing the container 10 in consideration of clogging and staying of the developer.

  The dust reduction mechanism FTK of the developing device DD1 is provided in the housing gap HG, and as shown in FIG. 11, is an inner wall surface of the accommodating portion 10 that is located downstream of the opening 102 in the rotation direction of the developing roller 11. The opposing portion 60 having the opposing surface 601 that is at least part of the inner wall surface that is not immersed in the developer when the developer is accommodated in the accommodating portion 10 up to the maximum accommodation amount, and the opposing surface 601 is provided on the developing roller 11. A compression spring 61 as an urging portion that urges the facing portion 60 so as to face, and abutting against the facing portion 60, a predetermined distance between the facing surface 601 and the surface of the developing roller 11 facing the facing surface 601 is predetermined. The cam 62 as a restricting portion that restricts the facing portion 60 so as to keep the interval of the housing gap HG constant is maintained.

  According to the developing device DD1 provided with such a dust prevention mechanism FTK, as shown in FIG. 11, the opposing surface 601 is urged toward the developing roller 11, and, for example, in a high temperature environment, the accommodating portion Even if 10 thermally expands, it expands in a direction (T5 direction in FIG. 11) toward the opposite side to the biasing direction (T4 direction in FIG. 11), and the compression spring 61 is further compressed. Even if the accommodating portion 10 is deformed and contracted, it is urged in the urging direction by the compression spring 61. That is, the length of the housing gap HG does not change.

  In addition, in the image forming apparatus GS1 including the developing device DD1, as illustrated in FIG. 12, the control unit 90 rotates the cam 62 connected to the second gear Ga2 by driving the first gear Ga1. Control is performed so that the facing surface 601 moves toward the developing roller 11 by the amount of decrease in the length of the magnetic brush on the developing roller 11 set based on the equivalent amount of accumulated toner consumption in the developing device DD1, in other words. The controller 90 moves the opposing surface 601 from the first position i1 to the second position i2, which is a position moved from the first position i1 in the urging direction by a decrease in the length of the magnetic brush. The powder smoke reduction operation FTD can be controlled.

  Hereinafter, the smoke reduction mechanism FTK will be described more specifically with reference to FIGS. 13 to 16.

  As shown in FIG. 13, the facing portion 60 has a facing surface 601. The facing surface 601 is provided at a position facing the magnetic pole MP4 of the developing roller 11, and is biased in the biasing direction by the compression spring 61. More specifically, the facing portion 60 is provided so that the central portion in the short direction of the facing surface 601 faces the magnetic pole MP4. Further, the end of the thickness of the facing portion 60 in the T5 direction is at the initial position iS. The facing portion 60 is provided so that the facing surface 601 is in a position where the developer is not immersed in the developer when the developer is accommodated up to the maximum capacity of the housing area 101, but part of the facing surface 601 is provided. May be provided so as to constitute the accommodating area 101.

  The facing portion 60 is not necessarily provided so that the central portion in the short direction faces the magnetic pole MP4, and may be provided so as to face at least a part of the magnetic force distribution of the magnetic pole MP4. Further, as shown in FIG. 14, the length in the longitudinal direction of the facing portion 60 is preferably equal to or longer than the length in the rotation axis direction of the developing roller, but may be shorter than that. For example, the image forming apparatus GS1 provided with the developing device DD1 may be provided at a position corresponding to a portion without the recording medium P when the recording medium P having a width narrower than the maximum size recording medium P that can be used is used. .

  The facing portion 60 is made of a thermoplastic resin such as ABS (acrylonitrile-butadiene-styrene resin) in the same manner as the housing portion 10 so as to be easily formed into a shape having a curved surface along the diameter of the developing roller 11. ing. Here, since the shape of the facing portion 60 is more complicated and larger than that of the cam 62, variation in dimensions tends to occur during manufacture.

  The compression spring 61 as an urging portion is provided between the facing portion 60 and the housing portion 10, and one end side is connected to the facing portion 60 and the other end side is connected to the housing portion 10. The compression springs 61 are provided at both ends in the longitudinal direction of the facing portion 60, but may be provided over the entire longitudinal direction of the facing portion 60.

  The cam 62 as the restricting portion has a shape in which the distance from the rotation axis is not constant, is disposed so that the portion where the length in the radial direction is the maximum is at a position corresponding to the magnetic pole MP4, and on the opposing surface 601. It is provided to come into contact.

  The cam 62 provided in this way regulates the facing surface 601, so that the distance between the facing surface 601 and the surface of the developing roller 11 facing the facing surface 601 is maintained at a predetermined length W1, and the housing gap The interval is kept constant. As a result, the entire magnetic brush formed on the outer peripheral surface of the developing roller 11 at the position of the magnetic pole MP4 can be maintained so that the interval of the housing gap is constant. Here, the term “constant” is a concept including substantially constant.

  More precisely, the cam 62 is interposed between the opposing surface 601 and the axial center of the first shaft 113, so that the distance between the opposing surface 601 and the axial center of the first shaft 113 is increased. Although the length is maintained at a predetermined length, the variation in size when the developing roller 11 is manufactured is so small as to be negligible as compared with the variation in size when the housing portion 10 is manufactured, and also due to a temperature change around the developing roller 11. Since the degree of thermal deformation (deformation amount) is negligibly small as compared with the facing portion 60, the distance between the facing surface 601 and the surface of the developing roller 11 facing the facing surface 601 is substantially the predetermined length. Can be kept at W1.

  Further, the cam 62 is not limited to be installed so that the portion where the length in the radial direction is the maximum is at the position of the magnetic pole MP4, and it is sufficient that the cam 62 is in contact with at least a part of the facing surface 601.

  The cam 62 has a simple configuration as compared with the facing portion 60, and therefore, variations in dimensions and the like are small during manufacture. Further, the cam 62 is made of a material that is difficult to be thermally deformed. For example, the cam 62 is made of super engineering plastic such as PS (polystyrene resin) or PPS (polyphenylene sulfide resin) containing glass. That is, it is made of a material such as a resin having a higher thermal deformation temperature (a deflection temperature under load) than the facing portion 60. Thereby, compared with the opposing part 60, it is hard to carry out a heat deformation with respect to the surrounding temperature change.

  Here, as shown in FIG. 15, when the facing portion 60 expands due to a change in ambient temperature, the facing portion 601 is in contact with the cam 62, so the facing portion 60 expands in the T5 direction and the compression spring 61. Is more compressed. That is, the position of the end portion in the T5 direction of the thickness of the facing portion 60 changes from the initial position iS to the expansion position iE. Further, as shown in FIG. 16, even when the accommodating portion 10 is deformed and contracted, it is urged by the compression spring 61 in the urging direction. That is, the position of the end portion in the T5 direction of the thickness of the facing portion 60 changes from the initial position iS to the contracted position iC. Therefore, the length of the housing gap HG does not change. Further, even when the housing portion 10 to which the compression spring 61 is connected is thermally deformed, the length of the housing gap can be kept constant similarly. In addition, even when the manufacturing unit 10 and the opposing unit 60 have variations in dimensions during manufacturing, the value set at the time of manufacturing is set for the length of the housing gap HG of each developing device DD1 by the same operation. It can be secured.

  Thus, according to the developing device DD1 provided with the dust prevention mechanism FTK, the fluctuation of the housing gap HG due to the deformation of the housing portion 10 due to the ambient temperature change is suppressed. Accordingly, it is possible to reduce the ejection of the dust toner due to the change in the housing gap, and it is possible to prevent clogging and retention of the developer.

  Further, according to the developing device DD1 provided with the dust prevention mechanism FTK, the variation in the housing gap HG due to the variation in the dimensions at the time of manufacturing the housing portion 10 is further suppressed. Therefore, in each developing device, it is possible to prevent clogging and retention of the developer in the housing gap HG, and it is possible to maintain the housing gap interval so as to reduce the amount of dust toner ejected. Variation in quality can be reduced.

<Powder smoke reduction operation FTD>
Next, with reference to FIG. 12 and FIGS. 17 to 19, the smoke reduction operation in the image forming apparatus GS1 including the developing device DD1 will be described.

  The control unit 90 includes a counting unit that counts the number of image formations as the amount of accumulated toner consumption in the developing device DD1 from when the developing device DD1 is attached to the main body of the image forming device GS1. Note that the number of image formations counted by the counting means is stored in the memory 91 and updated with image formation. The number of image formations stored in the storage unit is initialized when the developing device DD1 is newly attached after the developing device DD1 is removed from the image forming device GS1.

  As shown in FIG. 12, the control unit 90 drives the first gear Ga1 based on the number of image formations counted by the counting means, thereby rotating the cam 62 connected to the second gear Ga2 to face the first gear Ga2. The predetermined length, which is the length of the space between the surface 601 and the surface of the developing roller 11 facing the facing surface 601, is changed from W1 to W1 ′. The first gear Ga1 and the second gear Ga2 are also provided at the end of the developing roller 11 on the opposite side in the longitudinal direction, and are similarly driven by the control unit 90.

  More specifically, the predetermined length when the developing device DD1 is attached to the main body of the image forming apparatus GS1 is W1, the predetermined length after the change is W1 ′, and the developing device DD1 is connected to the main body of the image forming apparatus GS1. When the length of the magnetic brush formed on the surface of the developing roller 11 facing the facing surface 601 when mounted is W2 and the length of the magnetic brush shortened with durability is W2 ′, the control unit 90 The first gear Ga1 is driven so that the predetermined length W1 ′ after the change is shorter than the predetermined length W1 by a length corresponding to the length difference between W2 and W2 ′. . That is, the difference in length between the predetermined lengths W1 and W1 ′ (W1−W1 ′) is the difference in length between the magnetic brush lengths W2 and W2 ′ (W2−W2 ′). Become. Therefore, as shown in FIGS. 17 and 18, the housing gap is kept constant regardless of the number of images formed. At this time, the facing surface 601 moves from the first position i1 toward the second position i2 on the biasing direction side from the first position i1.

  Further, when the developing device DD1 is removed from the main body of the image forming apparatus GS1 and the developing device DD1 is attached to the main body of the image forming apparatus GS1 again, the full detection sensor indicates that the developing device DD1 has been filled with the developer. When detected, the control unit 90 can drive the first gear Ga1 so as to move the facing surface 601 from the second position i2 to the first position i1.

  Here, as shown in FIG. 19, the control unit 90 refers to the table 1 stored in the memory 91 to determine a predetermined length W1 ′ corresponding to the number of formed images counted by the counting unit. The cam 62 is rotated so that the predetermined length is W1 ′.

  For example, when the number of image formations counted by the counting unit is less than 5000, the control unit 90 does not perform the smoke reduction operation FTD, and the number of image formations counted by the counting unit is 5001. The control unit 90 rotates the cam 62 based on the table 1 so that the predetermined length W1 is narrowed by 0.05 mm, that is, the control unit 90 changes the predetermined length from W1 to W1 ′. .

  Thereafter, when the number of image formations counted by the counting unit is less than 10,000, the control unit 90 does not perform the smoke reduction operation FTD and maintains the predetermined length at W1 '. When the number of image formations counted by the counting unit reaches 10001, the control unit 90 sets the predetermined length W1 ′ to be a value obtained by narrowing the predetermined length W1 by 0.10 mm based on the table 1. The cam 62 is rotated. That is, the control unit 90 further narrows the predetermined length W1 'by 0.05 mm. Hereinafter, similarly, based on the table 1, the predetermined length W1 'is determined.

  Here, the table 1 indicates the height of the magnetic brush formed on the developing roller 11 constituting the housing gap with respect to the change in the number of image formations in the image forming apparatus GS1 including the developing device DD1, that is, the durability change. It is created based on the experimental result of FIG. Note that the number of formed images and the corresponding value of W1-W1 'shown in Table 1 are merely examples, and are not limited to these. For example, the control unit 90 may perform control so that the value of W1-W1 ′ is increased stepwise according to the number of image formations.

  According to the image forming apparatus GS1 capable of performing such a dust reduction operation FTD, the housing according to the degree of durability of the developing device DD1, in other words, according to the equivalent amount of accumulated toner consumption in the developing device DD1. Since the length of the gap HG can be adjusted, in particular, it is possible to reduce the dust of floating toner generated due to a decrease in the charge amount of the developer.

  According to the developing device DD1 as described above, the provision of the dust reduction mechanism FTK can suppress the fluctuation of the housing gap HG due to the deformation of the housing portion 10 due to the surrounding temperature change, and at the time of manufacturing the housing portion 10 Regardless of the variation in size, it is possible to prevent the deterioration of the developer changeability and the clogging of the developer, and to reduce the generated floating toner dust. Accordingly, variation in quality among the developing devices to be manufactured is suppressed, and in the image forming apparatus GS1 provided with the developing device DD1, image disturbance due to deterioration of developer changeability and the like are prevented, and the recording medium S The occurrence of dirt can be suppressed.

  In addition, in the image forming apparatus GS1 including the developing device DD1, the control unit 90 performs the smoke reduction operation FTD using the dust reduction mechanism FTK, in other words, according to the durability level of the developing device DD1. Since the length of the housing gap HG can be adjusted according to the amount corresponding to the cumulative consumption amount of toner in the device DD1, in particular, it is possible to reduce the dust of floating toner generated due to the decrease in the charge amount of the developer.

  The developing device DD1 and the image forming device GS1 are merely examples and do not limit the present invention. Accordingly, the present invention can be variously improved and modified without departing from the scope of the invention. For example, the developing device DD1 may be a one-component developing device using a developer that does not include a carrier. In the case of a one-component developing device, the facing surface 601 is the position of the inner wall surface of the housing portion 10 that forms the housing gap HG downstream of the opening 102 in the rotation direction of the developing roller 11. What is necessary is just to provide in the position which hits the inner wall surface which is not immersed in the said developer, when the developer is accommodated in the part 10 to the maximum accommodation amount.

  20 and 21, the lower end portion 602 of the facing portion 60 in the short direction is fixed as a rotation fulcrum, and one end portion side (the upper side in FIG. 21) of the facing portion 60 in the short direction is fixed. It is good also as a structure which the compression spring 61 urges | biases the opposing part 60 so that it may rotate.

  The present invention can also be applied to a developing device that maintains a constant amount of developer in the developing device DD1 and replenishes toner containing a carrier. In such a developing device, by using a TCR sensor as a fullness detection sensor, it is possible to detect the ratio of carrier to toner in the developer and control the toner amount to be constant. In such a developing device, it may be determined whether or not to perform the smoke reduction operation FTD in accordance with the toner replenishment operation.

  The number of formed images is used as the amount corresponding to the cumulative consumption amount of toner in the developing device DD1, but is not limited thereto. For example, a toner detection unit that detects the remaining amount of toner stored in the storage unit 10 is provided, and the result of calculating the cumulative consumption of toner based on the remaining amount of toner detected by the toner detection unit is used as the cumulative consumption amount equivalent amount. It is good.

  The present invention can also be applied to tandem color copiers, monochrome copiers, printers, fax machines, and multi-function machines thereof.

GS1 Image forming apparatus S Recording medium 40 Automatic document conveying device 41 Document feeding table 42 Platen roller 43 Document discharge table 44 Document reversing conveying unit 20 Image reading unit 21 First scanning unit 22 Second scanning unit 23 Light receiving unit 24 Platen glass 300 Recording medium storage unit 301a, 301b, 301c Storage tray 302a, 302b, 302c Supply roller 310 Manual feed unit 311 Manual feed tray 50 Image forming unit 51 Image carrier 52 Charging device 53 Exposure device 55 Transfer unit 551 Transfer roller 56 Image Supporting member cleaning means 70 Fixing device 71 Pressure roller 72 Fixing roller 810 Discharge unit 90 Control unit 91 Memory 93 Operation panel SRB Recording medium registration unit
GRB Document registration portion G1 First transport guide G2 Second transport guide DD1 Developing device 10 Storage section 101 Storage area 102 Opening 103 Restriction member 11 Developing roller 111 Sleeve 112 Magnet body 113 First shaft 12 Transport roller 121 Second shaft T1 Image carrier rotation direction T2 Sleeve rotation direction T3 Airflow direction through the opening T4 Biasing direction T5 Direction opposite to the biasing direction MP1, MP2, MP3, MP4, MP5, magnetic pole FTK Powder smoke reduction Mechanism 60 Opposing portion 601 Opposing surface 61 Compression spring 62 Cam
i1 1st position
i2 2nd position
iS initial position
iE Expansion position
iC contraction position Ga1 first gear Ga2 second gear

Claims (6)

A storage portion for storing the developer, the storage portion having an opening;
A part of the surface exposed from the opening to the outside of the accommodating portion, and a developer carrying member that rotates while carrying the developer on the surface;
A regulating portion interposed between the rotation shaft of the developer carrying member and the inner wall surface of the housing portion,
The accommodating portion is
An inner wall surface located downstream of the opening in the rotation direction of the developer carrying member from the opening, and at least an inner wall surface that is not immersed in the developer when the developer is accommodated in the accommodating portion up to the maximum accommodation amount. A facing portion having a facing surface that is a portion;
A biasing portion that biases the facing portion in a direction in which the facing surface faces the developer carrying member;
The developing device according to claim 1, wherein the restricting portion is in contact with the facing portion to maintain a predetermined distance between the rotation shaft and the facing surface.
Comprising a magnet body fixedly arranged inside the developer carrier;
The developer includes a toner and a carrier,
The magnet body is
The developing device according to claim 1, further comprising a magnetic pole at a position facing the facing surface.
The developing device according to claim 1, wherein the restriction portion can change the predetermined length.
The regulation part is
A rotation shaft of the developer carrying member is rotatably provided, and has a cam contacting the facing portion;
The counter surface is moved in a direction in which the biasing portion biases the counter portion by rotation of the cam, or in a direction opposite to a direction in which the biasing portion biases the counter portion. Item 4. The developing device according to Item 3.
An image forming apparatus for forming an image on a recording medium, comprising the developing device according to claim 1.
An image forming apparatus for forming an image on a recording medium,
A developing device according to claim 3 or 4,
A drive unit that rotationally drives the regulating unit;
A control unit for controlling rotation of the regulating unit by the driving unit,
The controller is
An image forming apparatus, comprising: a calculating unit that calculates an equivalent amount of accumulated toner consumption in the developing device, wherein the predetermined length is changed based on the equivalent amount of accumulated consumption.

Images