JP2007334239A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device designed to efficiently and securely stir toner in a toner tank and prevent aggregation of toner and to provide an image forming apparatus. <P>SOLUTION: A stir blade 40 is rotated by being supplied with rotating/moving force from outside, and stirs toner in the toner tank 39. While the stir blade 40 is rotated in the lower part of its rotating/moving area S, it does not come into contact with a stir interlocking member 41 formed of resin. Also, the stir interlocking member 41 is moved downward by being pushed by an elastic plate member 43. In addition, when the stir blade 40 is rotated/moved in the upper part of the rotating/moving area S, it comes into contact with and pushes up the stir interlocking member 41, and rotates the stir interlocking member 41 by its slide contact with the member 41. Thereafter, in the same way as above, the stir interlocking member 41 is rotated in one direction while repeatedly vibrated up and down accompanying the rotation/movement of the stir blade 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a developing device used in an electrophotographic image forming apparatus and an image forming apparatus including the developing device.

  As a developer used in an image forming apparatus adopting an electrophotographic system, a one-component developer composed only of toner and a two-component developer composed of toner and carrier are known.

  When a two-component developer is used, the developer composed of toner and carrier is stirred in the developer tank so that the toner is charged and the toner is adhered to the surface of the carrier. The developer in this state adheres to the outer periphery of the developing roller, and is conveyed to a developing region at a position where the photosensitive drum carrying the electrostatic latent image and the developing roller are opposed to each other. As a result, a sufficient amount of toner can be obtained and a high density image can be obtained.

  However, when a two-component developer is used, it is necessary to maintain a constant mixing ratio of the toner and the carrier in order to maintain a constant development density, and the configuration of the entire developing device including the developer tank is complicated. There is a problem of becoming.

  In addition, when a one-component developer is used, handling is simpler than when a two-component developer is used. As the one-component developer, non-magnetic toner is known, and this non-magnetic toner is conveyed to a nip region between the developing roller and a blade plate that regulates the toner layer thickness. As a result, a toner layer having a constant film thickness adheres to the peripheral surface of the developing roller, and this toner layer is conveyed to a developing region at a position where the photosensitive drum and the developing roller are opposed to each other.

  On the other hand, in recent years, an image forming apparatus employing a color electrophotographic system has become widespread. In this image forming apparatus, for example, a plurality of toner image forming units that perform charging, exposing, and developing processes on the photosensitive drum are arranged in the horizontal direction, and the toner image forming units are arranged at positions facing the photosensitive drum. A transfer conveyance belt for sequentially transferring the recording medium is provided.

  Each toner image forming unit forms toner images of different colors, that is, black, cyan, magenta, and yellow on the photosensitive drum, and these toner images are transferred to plain paper or an OHP sheet via a transfer conveyance belt. The image is sequentially transferred onto a final recording medium such as the above, or directly transferred onto the recording medium conveyed on the transfer conveyance belt.

  An image forming apparatus in which such toner image forming units are arranged side by side is called a tandem system. This tandem type image forming apparatus has an advantage that the image forming speed is faster than other methods in which a single photosensitive drum is used to superimpose a toner image on paper wound around a transfer drum. Yes. Further, it is said that the use of the above-described non-magnetic toner, which is a one-component developer, is excellent in terms of high image quality and color compatibility.

In addition, in consideration of environmental issues in recent years, various additions such as wax to improve the releasability from the fixing device, instead of the silicone oil used in the fixing device for fixing the toner on the recording medium. A technique of adding a product to the toner itself is employed.
Further, in a color electrophotographic image forming apparatus, since fixing is performed in a state where toners of two or more colors are superimposed, a toner having higher fixability is required.

In order to save energy, there is a tendency to use a toner having a low average molecular weight that enables fixing at a lower temperature.
Furthermore, the toner particle size tends to be smaller for the purpose of high resolution.

  Such recent toners tend to aggregate in the developer tank as compared to previous toners. In order to prevent this, a stirring mechanism is provided in the developer tank, but in a developer tank having a complicated internal structure, there is a dead space that is not sufficiently stirred.

  For example, in the conventional developer device as shown in FIG. 10, although the stirring blade 102 is rotated in the developer tank 101 and the toner is stirred, a dead space 103 where the toner is not stirred is above the stirring blade 102. There is a phenomenon that toner in the dead space 103 is aggregated and toner is not replenished satisfactorily.

Therefore, conventionally, the aggregation of the toner in the dead space has been solved by applying an impact to the outer wall surface of the developer tank or by installing a new stirring mechanism in the developer tank.
However, these methods have a problem in that vibration noise is generated and a new driving device is required.

For this reason, in Patent Document 1, as shown in FIGS. 11 and 12, a stirring blade 112 and a coiled spring 113 are provided in the developer tank 111, and the stirring blade 112 is rotated to stir the toner. Further, the stirring blade 112 is brought into contact with the coiled spring 113 and the coiled spring 113 is deformed while being moved to a space in the developer tank 111 where the stirring blade 112 does not reach. The toner is agitated.
Japanese Patent No. 2935667

  By the way, in order to elastically deform the coiled spring 113 by the contact of the stirring blade 112 as in Patent Document 1, it is necessary to make the coiled spring 113 very thin or thin or made of a flexible material.

However, if the coil spring 113 is made very thin or thin or made of a flexible material, the stirring ability of the toner by the coil spring 113 is lowered, and the agglomerated toner cannot be released.
Further, the stirring blade 112 is easily entangled with the coiled spring 113, and the motor that rotationally drives the stirring blade 112 is locked.

  In addition, in order to elastically deform the coiled spring 113 by contact with the stirring blade 112 after applying a coil spring 113 having sufficient elastic force, the rotational force of the stirring blade 112 is very large. There is a need to. In this case, the torque of the motor that rotationally drives the stirring blade 112 must be increased, and the power consumption of the motor increases. In addition, since most of the power consumption of the motor is used for the deformation of the coiled spring 113 regardless of toner agitation, the efficiency becomes very low.

  In addition, by adopting a spring shape, when the pitch of the spring is fine or when the toner is sufficiently seen in the developing layer, the effect is remarkably reduced, and in the worst case, the spring itself moves the toner. It becomes a hindrance factor.

  Therefore, the present invention has been made in consideration of the above-mentioned circumstances, and it is possible to efficiently and surely solve the developer in the developer tank, to prevent the developer from aggregating, and to stabilize the developing portion. In particular, it is an object of the present invention to provide a developing device and an image forming apparatus capable of moving toner.

In order to solve the above problems, the present invention is configured as follows.
In the developing device of the present invention, the developer is stored in the developer tank, and the developer is supplied from the developer tank to the developing unit while the developer is stirred by rotating the stirring member in the developer tank. In the developing device, the stirring interlocking member made of a resin positioned above the stirring member, and a regulating member inserted in the center of the stirring interlocking member and restricting the movement region of the stirring interlocking member, The moving region of the stirring interlocking member and the rotational moving region of the stirring member are set so as to interfere with each other.

Since the moving region of the stirring interlocking member interferes with the rotational moving region of the stirring member, the stirring interlocking member rotates in contact with the stirring member and rotates at the same time, and the aggregation of the toner in the space where the stirring member in the developer tank does not reach is solved. The developer can be smoothly supplied from the developer tank.
Further, there is no need to elastically deform the stirring interlocking member. For this reason, the stirring member does not need to be used for the elastic deformation of the stirring interlocking member. There is no need to increase the rotational force.
Furthermore, since the movement region of the stirring interlocking member is regulated by the regulating member, the rotation of the stirring member is not hindered or the movement region is not deviated from the rotational movement region of the stirring member at all. However, the toner aggregation can always be solved.

  In the developing device of the present invention, a biasing means for biasing the stirring interlocking member is provided at a position above the stirring interlocking member on the stirring member side positioned below the stirring interlocking member. The interlocking member is brought into contact with the stirring member to rotate and vibrate.

  When such an urging means is provided, the movement area of the stirring interlocking member and the rotational movement area of the stirring interlocking member interfere with each other constantly and reliably, and the stirring interlocking member moves and rotates in contact with the stirring member. The member continuously rotates and vibrates, whereby the toner in the developer tank is agglomerated and the developer is smoothly supplied from the developer tank.

  Furthermore, in the developing device of the present invention, the cross-sectional area ratio of the rod-shaped member that serves to connect the rotating members of the agitation interlocking member and to release the developer is larger than the total area in the outer periphery of the cross section of the rotating member. It is 10% or less, and the replenishment is smoothly performed without hindering the movement of the developer from the developer tank to the developing unit.

  Further, the outer periphery of the rotating body of the agitation interlocking member is formed in an uneven shape so that the agitation interlocking member rotates in contact with the agitation member in the rotational movement region of the agitation member. The movement will be performed smoothly.

  Furthermore, the agitation interlocking member has at least one agitation interlocking member arranged at a position above the agitation member, and has two or more agitation interlocking members having the same or different shapes. I did it.

On the other hand, an image forming apparatus of the present invention includes the developing device of the present invention.
In such an image forming apparatus of the present invention, the same operations and effects as those of the developing apparatus of the present invention can be achieved.

  According to the present invention, the agitation interlocking member is set so that the movement region thereof interferes with the rotation movement region of the agitation member, and comes into contact with the agitation member and the urging means for urging the agitation member side to vibrate up and down At the same time, it rotates to release toner aggregation in the space where the stirring member in the developer tank does not reach, and to smoothly replenish the developer from the developer tank.

  Further, there is no need to elastically deform the interlocking member. Therefore, the stirring member does not need to be spent for elastic deformation of the stirring interlocking member. There is no need to make it extremely large.

  Furthermore, since the movement region of the stirring interlocking member is regulated by the regulating member, the rotation of the stirring member is not hindered or the movement region is not deviated from the rotational movement region of the stirring member at all. Therefore, the toner aggregation can be always solved, and the developer supply from the developer tank is smoothly performed.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a developing device of the present invention and an image forming apparatus including the developing device will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a configuration of an image forming apparatus 100 according to this embodiment. In FIG. 1, the image forming apparatus 100 forms first to fourth image forming stations that form toner images on a recording paper P. Each of the laser beam scanner units 27a, 27b, 27c for exposing Pa, Pb, Pc, Pd and the photosensitive drums 22a, 22b, 22c, 22d of the first to fourth image forming stations Pa, Pb, Pc, Pd. 27d.

  A first image forming station Pa, a second image forming station Pb, a third image forming station Pc, and a fourth image forming station Pd are arranged in parallel from the upstream side of the transfer conveyance belt 16 in the vicinity of the transfer conveyance belt 16. Has been. These image forming stations Pa, Pb, Pc, and Pd have substantially the same configuration, and the laser beam scanner units 27a, 27b, 27c, and 27d have substantially the same configuration. . For this reason, in the following description, the reference numerals for the description of the same configuration are representative of those of the first image forming station Pa and the laser beam scanner unit 27a, and the second, third, and fourth image forming stations Pb. , Pc, Pd and the reference numerals corresponding to those of the laser beam scanner units 27b, 27c, 27d are omitted.

  The first image forming station Pa is rotationally driven in the direction of arrow F shown in FIG. 1 to form a photosensitive drum 22a on which an electrostatic latent image is formed, a charger 23a that uniformly charges the photosensitive drum 22a, and a photosensitive drum. A developing device 24a for developing the electrostatic latent image formed on the photosensitive drum 22a, a transfer discharger 25a for transferring the developed toner image on the photosensitive drum 22a to the recording paper P, and the photosensitive drum 22a. And a cleaning device 26a for removing residual toner. The charger 23a, the developing device 24a, the transfer discharger 25a, and the cleaning device 26a are sequentially arranged in the periphery along the rotation direction F of the photosensitive drum 22a.

  The laser beam scanner unit 27a is disposed on the upper side of the photosensitive drum 22a, and a semiconductor laser element (not shown) that emits dot light modulated according to image data, and a laser beam from the semiconductor laser element. A polygon mirror 271 for deflecting in the main scanning direction, an axisymmetric aspherical lens (fθ lens) 272 for imaging the laser beam deflected by the polygon mirror 271 on the surface of the photosensitive drum 22a, and a mirror 273 274.

  The laser beam scanner unit 27a has a pixel signal corresponding to the black component image of the color document image, the laser beam scanner unit 27b has a pixel signal corresponding to the cyan component image of the color document image, and the laser beam scanner unit 27c has a pixel signal. The pixel signal corresponding to the magenta color component image of the color original image is input to the laser beam scanner unit 27d, and the pixel signal corresponding to the yellow color component image of the color original image is input thereto.

  Thereby, electrostatic latent images corresponding to the color-converted document image information are formed on the respective photosensitive drums 22a, 22b, 22c, and 22d. The developing device 24a contains black toner, the developing device 24b contains cyan toner, the developing device 24c contains magenta toner, and the developing device 24d contains yellow toner. The electrostatic latent images on the photosensitive drums 22a, 22b, 22c, and 22d are developed with the toners of these colors. Thus, the document image information color-converted by the image reading unit is reproduced as a toner image of each color.

  A paper suction charger 28 is disposed between the first image forming station Pa and the paper feed mechanism 11, and the paper suction charger 28 charges the surface of the transfer conveyance belt 16. Thus, the recording paper P supplied from the paper feeding mechanism 11 is reliably adsorbed on the transfer conveyance belt 16 and conveyed between the first image forming station Pa and the fourth image forming station Pd without deviation. It is.

  Further, a static eliminator 29 is disposed between the fourth image forming station Pd and the fixing device 17 and substantially directly above the driving roller 14. An AC current for separating the recording paper P electrostatically attracted to the transfer conveyance belt 16 from the transfer conveyance belt 16 is applied to the static eliminator 29.

  In the image forming apparatus of the present embodiment, cut sheet-like paper is used as the recording paper P. When the recording paper P is fed out from the paper feeding cassette and supplied into the guide of the paper feeding / conveying path of the paper feeding mechanism 11, its leading end is detected by a sensor (not shown) and output from this sensor. Based on the detected signal, the pair of registration rollers 12 are temporarily stopped.

  The recording paper P is fed onto the transfer conveyance belt 16 rotating in the direction of arrow Z in FIG. 1 at the timing of each image forming station Pa, Pb, Pc, Pd. At this time, since the transfer conveying belt 16 is charged by the sheet adsorbing charger 28 as described above, the recording sheet P is passing through the image forming stations Pa, Pb, Pc, Pd. Is transported stably.

  In each image forming station Pa, Pb, Pc, Pd, a toner image of each color is formed, and each toner image is superimposed on the recording paper P conveyed by being electrostatically attracted by the transfer conveyance belt 16. When the transfer of the image by the fourth image forming station Pd is completed, the recording paper P is sequentially peeled off from the transfer conveyance belt 16 by the static eliminator 29 from the leading end portion thereof and guided to the fixing device 17. Finally, the recording paper P on which the toner image is fixed is discharged onto a paper discharge tray 20 from a paper discharge port (not shown).

  In the image forming apparatus of the present embodiment, optical writing is performed by scanning the laser beam by the laser beam scanner unit 27a and exposing the photosensitive drum 22a. However, instead of the laser beam scanner unit 27a, the laser beam scanner unit 27a performs optical writing. A writing optical system (LED head) composed of a light emitting diode array and an imaging lens array may be used. The LED head is smaller than the laser beam scanner unit 27a, has no moving parts, and is silent. Therefore, it is suitable for a tandem image forming apparatus that requires a plurality of optical writing units.

  FIG. 2 is a schematic diagram showing the first image forming station Pa in the image forming apparatus of the present invention. The other second to fourth image forming stations Pb, Pc, and Pd have the same configuration and will not be described.

  Around the photosensitive drum 22a, a charger 23a for charging the surface potential of the photosensitive drum 22a to be constant at −500 V, the photosensitive drum 22a is exposed, and an electrostatic latent image is transferred to the surface of the photosensitive drum 22a. A laser beam scanner unit 27a (not shown) formed on the photosensitive drum 22a is brought into contact with the photosensitive drum 22a in the nip region, and the toner is supplied to the photosensitive drum 22a to be formed on the surface of the photosensitive drum 22a. A developing roller 34a, which is a toner carrier that develops the electrostatic latent image, and a cleaning device 26a that removes toner remaining on the surface of the photosensitive drum 22a are disposed around the rotation direction F of the photosensitive drum 22a. They are arranged sequentially.

  The photosensitive drum 22a includes a conductive substrate made of metal or a synthetic resin material, an undercoat layer formed on the surface of the conductive substrate, and a photosensitive layer formed on the surface of the undercoat layer, as shown in the figure. It is configured to rotate in the direction of F.

The developing roller 34a is configured to rotate in the direction E shown in the drawing. This rotation is realized by a rotation drive unit 38a including a power source such as a motor and a power transmission mechanism including gears and the like.
The developing roller 34a has a conductive support as a center and the periphery thereof is covered with an elastic body. The elastic body is formed from a rubber material having conductivity and elasticity by adding a conductive agent such as carbon black. Examples thereof include urethane rubber, silicone rubber, and NBR (Nitrile-Butadiene Rubber) rubber. In addition, the elastic body of this embodiment shall be formed with the polyurethane rubber whose volume resistance is 5 * 10 < ⁶ > ohm-cm, for example.

  On the surface of this elastic body, a coat layer forming the surface layer of the developing roller 34a is provided. Since this coat layer is a layer that carries toner, toner transportability, toner filming prevention, abrasion resistance, toner chargeability to a predetermined polarity, adhesion to an elastic body, and elastic body machinery The material is selected such that the follow-up property to the mechanical deformation is good. For example, materials such as nylon or vinyl, urethane resin, silicone resin, fluorine-containing resin are suitable, and the coating layer uses these synthetic resins as the base material, and ensures conductivity with materials that promote charging with toner. For example, it is coated on an elastic body by performing a treatment such as dispersing carbon.

The hardness of the developing roller 34a is preferably 50 to 90 degrees in Asker C, and the volume resistivity is preferably 10 ⁴ to 10 ⁸ Ωcm. When the volume resistivity is 10 ⁶ to 10 ⁷ Ωcm, the characteristics of the developing roller 34a are best.

  A sponge roller 35a for supplying toner to the developing roller 34a is disposed in contact with the developing roller 34a, and the toner layer thickness on the surface of the developing roller 34a is regulated and the toner is charged. A doctor blade 36a, which is a restricting member, is also disposed in contact with the doctor blade 36a.

The sponge roller 35a is a conductive elastic foam roller having a diameter of 20 mm made of a conductive urethane foam having a volume resistivity of about 10 ⁵ Ωcm, a cell density of 80 to 140 pcs / inch, and an Asker C hardness of 60 degrees to an Asker C hardness of 30 degrees. is there.

  The doctor blade 36a uses a thin plate-like spring member such as stainless steel or phosphor bronze and is brought into contact with the developing roller 34a so as to apply a required pressure contact force. As a contact method, a counter contact method is employed in which the free end is positioned upstream of the fixed end in the rotation direction of the developing roller 34a.

  The toner used in the image forming apparatus as described above is fine particles having an average particle diameter of 4 to 9 μm. As a method for producing such fine particles, a so-called pulverization method in which a resin, a colorant or the like is melt-kneaded and then pulverized and classified is generally used. In addition, a toner manufacturing method called a wet method has been proposed. In this wet method, a monomer (monomer) in which a colorant or an additive is dispersed in an aqueous medium in the presence of a dispersion stabilizer. There are a suspension polymerization method, an emulsion polymerization method, a phase inversion emulsification method and the like for polymerization.

Examples of the binder resin material used for the toner include styrene resins such as polystyrene or polystyrene-acrylic acid ester copolymers, vinyl chloride resins, phenol resins, epoxy resins, polyester resins, polyether polyol resins, polyurethane resins or 1 type (s) or 2 or more types chosen from groups, such as polyvinyl butyral resin, may be used.
The binder resin material may be one in which crystalline waxes or incompatible substances are finely dispersed in advance from the synthesis stage.
However, among the binder resin materials described above, polyester resins or polyether polyol resins are excellent in thermal properties such as resin elasticity, and therefore it is desirable to use them for the binder resin material.

  The glass transition point temperature (Tg) of the polyester resin or the polyether polyol resin is suitably in the range of 50 to 90 ° C. from the viewpoint of the thermal fixability and storage stability of the toner. The number average molecular weight (Mn) of the polyester resin or polyether polyol resin is suitably in the range of 3,000 to 100,000. When it is less than 3,000, it is difficult to form particles, and when it is 100,000 or more, it is not preferable because it becomes high viscosity during phase inversion emulsification and affects the control of particle diameter and distribution. .

  The colorant used in the toner is not particularly limited as long as it is a variety of dyes and pigments that have been used as toner materials so far, and is organic or inorganic as shown below. Various dyes and pigments can be used. That is, examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline / black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome yellow, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, nablue yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Examples thereof include benzidine yellow GR, quinoline yellow lake, permanent yellow NCG and tartrazine lake.

  Examples of the orange colorant include compounds such as red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G or indanthrene brilliant orange GK.

  Also, red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, virazolone red, watching red, calcium salt, lake red C, lake red D, brilliant carmine Examples include 6B, eosin lake, rhodamine lake B, alizarin lake, or brilliant carmine 3B.

  Examples of purple colorants include compounds such as manganese purple, fast violet B, and methyl violet lake.

  Examples of the blue colorant include compounds such as bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, or induslen blue BC. .

  Examples of the green colorant include compounds such as chrome green, chromium oxide, pigment green B, micalite green lake, and final yellow green G.

  Furthermore, examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide.

  In the toner for developing the electrostatic latent image, components such as magnetic powder such as magnetite, hematite or various ferrites, an anti-offset agent, or a charge control agent can be blended as necessary in addition to the above materials.

The offset preventive agent used for the purpose of improving the fixing property of the toner is not particularly limited as long as it has been used as a toner material so far, and those shown below can be used.
For example, petroleum wax such as paraffin wax, oxidized paraffin wax or microcrystalline wax, mineral wax such as montan wax, animal and vegetable wax such as beeswax or carnauba wax, or polyolefin wax (such as polyethylene or polypropylene), Examples thereof include synthetic waxes such as oxidized polyolefin wax or Fischer-Tropsch wax. These offset inhibitors may be used alone or in combination of two or more.

  As the charge control agent, various substances from low molecular compounds to high molecular compounds can be used. For example, a quaternary ammonium salt compound, a nigrosine compound, an organometallic complex, a chelate compound, and a monomer having an amino group are homopolymerized. Alternatively, copolymerized polymer compounds and the like can be mentioned.

  In addition, inorganic fine powders such as silica fine powder, titanium oxide fine powder, and alumina fine powder are preferably used as the external additive or fluidizing agent added for the purpose of charge adjustment and surface resistance adjustment. These inorganic fine powders are made of silicone varnish, various modified silicone varnishes, silicone oils, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, and other organosilicons for hydrophobicity and chargeability control. It may be treated with a treating agent such as a compound. Moreover, 1 type, or 2 or more types chosen from the processing agent mentioned above may be used.

  Further, as other additives, for example, a lubricant such as polytetrafluoroethylene, zinc stearate, polyfluorinated vinylidene, or silicone oil particles (containing about 40% silica) is preferably used. Further, a small amount of white fine particles having a polarity opposite to that of the toner particles may be used as a developability improver.

  By the way, if a large amount of toner is stored in each of the developing devices 24a to 24d, it is possible to lengthen the replacement cycle of the developing device.

  In the tandem image forming apparatus as described above, the developing devices 24a to 24d are arranged close to each other. Therefore, in order to store a large amount of toner in the developing devices 24a to 24d, the developing devices 24a to 24d are used. It is necessary to make the toner tank 39 vertically long. In general, the agitating blade in the toner tank 39 agitates the toner by rotating. However, with only one stirring blade, the stirring blade does not reach, and a dead space where the toner is not sufficiently stirred is generated in the vertically long toner tank 39.

  In order to solve this problem, for example, a plurality of stirring blades may be arranged in the vertically long toner tank 39 so as not to cause a dead space. However, in order to rotate each stirring blade with a driving force from the outside of the toner tank 39, it is necessary to provide a driving force transmission mechanism for transmitting the external driving force into the toner tank 39 for each stirring blade. Since the toner is very fine particles as described above and the toner may leak out from a slight gap in the toner tank 39, such a driving force transmission mechanism has a sealing property. Required. However, when such a driving force transmission mechanism having a sealing property is attached to each stirring blade, the cost of the developing device increases.

  Therefore, in this embodiment, a stirring interlocking member composed of one stirring blade and a resin is provided in the toner tank 39, and one stirring blade is rotated by an external driving force, and the coiled interlocking member is used as the stirring blade. The toner in the toner tank 39 is agitated by the agitating blade and the coiled interlocking member, thereby preventing a dead space where the toner is not agitated.

FIG. 3 is a cross-sectional view showing the internal structure of each of the developing devices 24a to 24d.
As described above, the developing roller 34a is in contact with the sponge roller 35a for supplying toner to the developing roller 34a. The developing roller 34a is also in contact with a doctor blade 36a, which is a regulating member that charges the toner, while regulating the thickness of the toner layer on the surface of the developing roller 34a.

  The toner tank 39 is provided with a stirring blade 40 for stirring the toner. The agitating blade 40 is rotated by a rotational force applied from an external power source (not shown) via a driving force transmission mechanism, and agitates the toner in the toner tank 39 to prevent the toner from aggregating. Toner is supplied to the sponge roller 35a.

  A stirring interlocking member 41 is provided above the stirring blade 40, and an elastic plate 43 is provided above the stirring interlocking member 41. The agitation interlocking member 41 is made of resin. The elastic plate 43 is formed of a PET film having a thickness of about 50 to 300 μm and is attached to the wall surface of the toner tank 39 with a double-sided tape or the like.

  FIG. 4 shows a cross-sectional view taken along line bb of FIG. FIG. 4 shows a case where the agitation interlocking member 41 is divided into a plurality of agitation interlocking members 41a, 41b, 41c, 41d, and the agitation interlocking members 41a, 41b, 41c, 41d are arranged.

  The restriction support shaft 44 is divided into a plurality of restriction support shafts 44 a to 44 h. The restriction support shafts 44 a and 44 h on both sides protrude from the side walls 39 a and 39 b of the toner tank 39, and the other restriction support shafts 44. The shafts 44b to 44g are supported by the respective arms 39d protruding from the side wall 39c of the toner tank 39. The regulating support shafts 44a and 44b are inserted into both ends of the stirring interlocking member 41a to support the stirring interlocking member 41a. Similarly, the regulation support shafts 44c and 44d are inserted into both ends of the stirring interlocking member 41b to support the stirring interlocking member 41b, and the regulation support shafts 44e and 44f are inserted into both ends of the stirring interlocking member 41c to interlock with stirring. The member 41c is supported, and the regulation support shafts 44g and 44h are inserted into both ends of the stirring interlocking member 41d to support the stirring interlocking member 41d.

  In FIG. 5, in the cross-sectional shape of the rotating body of the stirring interlocking member piece, there are two rod-shaped members that connect the rotating body and the rotating body to release the developer, and the cross-sectional area ratio is the outer circumference of the cross section of the rotating body. 4% of the stirring interlocking members 41b and 41c are shown with respect to the total area. In order for the stirring interlocking member piece to rotate in contact with the stirring member, the outer periphery of the rotating body of the stirring interlocking member piece is formed in an uneven shape.

In FIG. 6, there are three rod-shaped members that connect the rotating body to each other to release the developer, and the cross-sectional area ratio is 6% with respect to the total area in the outer periphery of the section of the rotating body. The members 41a and 41d are shown.
Here, the cross-sectional area ratio of the rod-shaped member may be at least 10% or less with respect to the entire area in the outer periphery of the cross section of the rotating body. If the rod-shaped member is provided at such a ratio, the developer The replenishment is smoothly performed without hindering the movement of the developer from the tank to the developing unit.

  Since the stirring interlocking member 41 is divided into the plurality of stirring interlocking members 41a to 41d, the plurality of stirring interlocking members 41a to 41d can be assembled with different shapes. Of course, the agitation interlocking member 41 can be assembled only at both ends, or the agitation interlocking member 41 may be a single agitation interlocking member 41 that is not divided.

  Here, as shown in FIG. 3, the agitation interlocking member 41 is supported by passing through the regulating support shaft 44, and is thus movable within a certain region. The moving region of the stirring interlocking member 41 interferes with the rotational moving region S of the stirring blade 40. The agitation interlocking member 41 is pushed downward by the elastic plate 43 and is always urged toward the agitation blade 40 side.

  The stirring blade 40 is rotated by being given a rotational force from the outside, and stirs the toner in the toner tank 39. As long as the agitating blade 40 is rotationally moved below the rotational movement region S as shown in FIGS. 3 and 4, the agitation interlocking member 41 is pushed by the elastic plate 43 without contacting the agitating blade 40. Move down.

  Next, when the stirring blade 40 is rotating above the rotational movement region S as shown in FIGS. 7 and 8, the stirring interlocking member 41 comes into contact with the stirring blade 40 and is pushed upward by the stirring blade 40. And is rotated in one direction by sliding contact with the stirring blade 40.

  Furthermore, when the stirring blade 40 rotates again to the lower side of the rotational movement region S, the stirring interlocking member 41 is pushed by the elastic plate 43 and moves downward.

  Similarly, as the stirring blade 40 rotates, the states of FIGS. 3 and 4 and the states of FIGS. 7 and 8 are repeated, and the stirring interlocking member 41 rotates in one direction while vibrating up and down.

  Therefore, in the vertically long toner tank 39, even in the upper space where the stirring blade 40 does not reach, the toner in the space is stirred by the stirring interlocking member 41, and the pseudo collection of toner is solved. As a result, the entire toner in the toner tank 39 is agitated, the pseudo-collection of the entire toner is solved, and the quality of the image recorded by the image forming apparatus is improved and stabilized.

Furthermore, since the stirring interlocking member 41 does not need to be elastically deformed unlike the coil spring 113 (see FIGS. 11 and 12) of Patent Document 1 described above, it is not necessary to increase the rotational torque of the stirring blade 40.
Further, since the movement region of the agitation interlocking member 41 is limited by the restriction support shaft 44b, the agitation member 41 is too close to the agitation blade 40 to inhibit the rotation of the agitation blade 40 or the rotation movement region of the agitation blade 40 It does not move away from S and does not come into contact with the stirring blade 40, so that toner stirring failure does not occur.

FIG. 9 is a cross-sectional view illustrating a modified example of the developing device. In FIG. 9, the same reference numerals are given to portions that perform the same functions as those in the apparatus of FIG. 3, and description thereof is omitted.
Here, a toner supply container 50 is detachably provided above the toner tank 39. In the toner supply container 50, a stirring blade 52 is provided, and the stirring blade 52 is rotated to stir the internal toner. A replenishing port 51 for replenishing toner from the toner replenishing container 50 to the toner tank 39 of the developing device 24a is provided below the toner replenishing container 50.

  The toner replenished from the replenishing port 51 is compressed near the replenishing port 51 and is easily packed. However, since the toner in the vicinity of the replenishing port 51 is released by the vertical vibration and rotation of the agitation interlocking member 41, the toner is not pseudo-collected, and the toner is smoothly replenished from the toner replenishing container 50 to the toner tank 39.

  Further, the toner supply container 50 is provided with a toner remaining amount detection unit (not shown). When the remaining amount of toner in the toner replenishing container 50 is low, the remaining amount detecting unit notifies the user of this fact and prompts the user to replace the toner replenishing container 50. As a result, the toner can be replenished before the toner runs out.

In addition, this invention is not limited to the said embodiment, It can deform | transform variously. For example, the present invention can be applied not only to an image forming apparatus that forms a color image but also to an image forming apparatus that forms only a monochrome image.
Further, the present invention can be applied to any developing device having any structure as long as it has a stirring member for stirring the developer in the developer tank.

1 is a longitudinal sectional view illustrating a configuration of an embodiment of an image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating an image forming station in the image forming apparatus of FIG. 1. FIG. 3 is a cross-sectional view showing an internal structure of a developing device in the image forming station of FIG. 2. It is a front view showing a resin interlocking member. It is a block diagram (bottom view, side view) and sectional drawing of a stirring interlocking member. It is another block diagram (bottom view, side view) and sectional drawing of a stirring interlocking member. FIG. 4 is a cross-sectional view showing an operating state of a toner tank in the developing device of FIG. 3. It is a front view which shows the operation state of the resin interlocking member of FIG. It is sectional drawing which shows the modification of a developing device. It is sectional drawing which shows the conventional image development apparatus. It is sectional drawing which shows the other conventional developing apparatus. FIG. 12 is a cross-sectional view showing an operating state of the developing device of FIG. 11.

Explanation of symbols

E: Rotating direction of developing roller, F: Rotating direction of photosensitive drum, P: Recording paper, Pa to Pd: First to fourth image forming stations, S: Rotating movement area of stirring blade, Z: Transfer conveying belt Transport direction 11... Paper feeding mechanism 12. Registration roller 14 and 15 Drive roller 16 Transfer transfer belt 17 Fixing device 20 Discharge tray 22a to 22d Photosensitive drum 23a to 23d Charger, 24a to 24d ... developing device, 25a to 25d ... transfer discharger, 26a to 26d ... cleaning device, 27a to 27d ... laser beam scanner unit, 271 ... polygon mirror, 272 ... axisymmetric aspheric lens (fθ) Lens), 273, 274 ... Mirror, 28 ... Charger for paper adsorption, 29 ... Static eliminator, 34a-34d ... Developing roller, 35a-35d ... Sponge 36a-36d ... Doctor blade, 38a-38d ... Rotation drive part, 39 ... Toner tank, 39a-39c ... Side wall of toner tank, 39d ... Arm protruding from the side wall of toner tank, 40 ... Stirring blade, 41, 41a to 41d ... stirring agitation member, 43 ... elastic plate material, 44, 44a to 44h ... regulating shaft, 50 ... toner supply container, 51 ... supply port, 52 ... stirring blade, 100 ... image forming apparatus, 101 ... development Agent tank, 102 ... stirring blade, 103 ... dead space, 111 ... developer tank, 112 ... stirring blade, 113 ... coil spring.

Claims (6)

In a developing device that stores developer in a developer tank, rotates the stirring member in the developer tank, and stirs the developer while supplying the developer from the developer tank to the developing unit. An agitation interlocking member made of resin located above the member, and a regulating member inserted in the center of the agitation interlocking member and restricting the movement region of the agitation interlocking member,
A developing device characterized in that the moving region of the stirring interlocking member and the rotational moving region of the stirring member are set to interfere with each other.   2. The developing device according to claim 1, wherein a biasing means for biasing the stirring interlocking member is provided on a side of the stirring member positioned below the stirring interlocking member at a position above the stirring interlocking member. A developing device, wherein the interlocking member contacts the stirring member and rotates and vibrates.   3. The developing device according to claim 1, wherein the cross-sectional area ratio of the rod-shaped member that serves to connect the rotating members of the stirring interlocking member and release the developer is equal to the total area in the outer periphery of the cross section of the rotating member. A developing device characterized by being 10% or less.   4. The developing device according to claim 1, wherein the agitation interlocking member has an outer periphery of a rotating body of the agitation interlocking member so that the agitation interlocking member rotates in contact with the agitation member in a rotational movement region of the agitation member. Is formed in a concavo-convex shape.   5. The developing device according to claim 1, wherein the stirring interlocking member includes at least one stirring interlocking member arranged at a position above the stirring member, and two or more stirring interlocking members are arranged. In the case of the members, the developing devices have the same or different shapes.   An image forming apparatus comprising the developing device according to claim 1.

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