JP2012032718A - Development device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming apparatus in which a developer conveying portion is hardly bent.
In a developing device 200 including a developing tank 201 that stores a developer and a developing roller 204 that carries and supplies the developer, the developing tank 201 has a first shape that surrounds a side surface of a virtual cylinder. and a two or more first deflection preventing beam 202b provided in parallel to the axis N ₁ of the virtual cylinder and spiral blade 202a, the developing roller by rotational movement about the axis N ₁ of the virtual cylinder 204 a first developer conveying unit 202 for conveying the developer toward providing a first deflection preventing beam 202b, provided over a plurality of locations at the outer peripheral portion T ₁ of the first spiral blade 202a, and the virtual shape of the cross section perpendicular to the axis N ₁ of the cylinder is provided such that the fan-shaped base around the said axis N _1.
[Selection] Figure 5

Description

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

  Copiers, printers, facsimiles, and the like include an image forming apparatus that forms an image by electrophotography. In an electrophotographic image forming apparatus, an electrostatic latent image is formed on the surface of a photosensitive drum by a charging device and an exposure device, and the electrostatic latent image is developed by supplying toner by a developing device. The toner image on the photosensitive drum is transferred to a recording medium such as recording paper, and the toner image is fixed on the recording paper by a fixing device, thereby forming an image.

  The developer containing toner supplied to the photosensitive drum by the developing device is stored in a developing tank provided in the developing device. The developer stored in the developing tank is conveyed to a developing roller provided in the developing device. The developing roller carries the developer on its surface and rotates to supply the developer to the photosensitive drum. The toner contained in the developer is frictionally charged in the process of being conveyed to the developing roller, and the charged toner is exposed to the photosensitive member from the developing roller by an electrostatic force between the electrostatic latent image on the surface of the photosensitive drum. Move on the drum. In this way, the developing device develops the electrostatic latent image on the surface of the photosensitive drum and forms a toner image.

  For example, Patent Document 1 describes a developing device that includes a developer transport unit having a rotating shaft that is a cylindrical member and a spiral blade that surrounds the rotating shaft. The developer conveying unit conveys the developer in the developing tank toward the developing roller by rotating the spiral blade around the axis as the rotation axis rotates around the axis. it can.

JP 2009-109741 A

  In the developing device described in Patent Document 1, when the amount of developer in the developing tank increases or when the rotation speed of the rotation shaft is large, the developer conveying unit is caused by friction between the spiral blade and the developer. There is a problem of bending. When the developer transport section is bent, the spiral blade and the inner wall of the developer tank are easily brought into contact with each other, and toner is sandwiched between the spiral blade and the inner wall of the developer tank to be compressed and agglomerated toner is generated. This will cause image defects.

  SUMMARY An advantage of some aspects of the invention is that it provides a developing device and an image forming apparatus in which a developer conveying portion is hardly bent.

The present invention relates to a developing device comprising a developing tank for storing a developer and a developing roller for supporting and supplying the developer.
The developing tank includes a spiral blade having a shape surrounding a side surface of the virtual cylinder and two or more anti-bending beams provided in parallel to the axis of the virtual cylinder, and the axis of the virtual cylinder is A developer transport unit configured to transport the developer toward the developing roller by a rotational movement around the center;
The bending prevention beam is provided over a plurality of locations in the outer peripheral portion of the spiral blade, and the shape of a cross section perpendicular to the axis of the virtual cylinder is a sector base centered on the axis. The developing device is characterized.

Further, the present invention provides a developing device comprising a developing tank for storing a developer and a developing roller for supporting and supplying the developer.
The developer tank includes a spiral blade having a shape surrounding a side surface of the virtual cylinder, and three or more anti-deflection beams provided parallel to the axis of the virtual cylinder at an outer peripheral portion of the spiral blade, A developer transport unit configured to transport the developer toward the developing roller by a rotational movement about an axis of a virtual cylinder;
In the developing device, the bending preventing beam is provided over a plurality of portions of the spiral blade.

  Further, the invention is characterized in that the shape of the cross section of the anti-deflection beam perpendicular to the axis of the virtual cylinder is a sector base centered on the axis.

  In the invention, it is preferable that the deflection preventing beams are provided so that all the distances from the axis are equal in a cross section perpendicular to the axis of the virtual cylinder.

  Further, the present invention is characterized in that the deflection preventing beams are provided such that, in a cross section perpendicular to the axis of the virtual cylinder, the installation angles formed by the two deflection preventing beams adjacent to the axis are all equal. And

The present invention also provides an electrophotographic image forming apparatus,
An image forming apparatus comprising the developing device.

  According to the present invention, the developer conveying unit includes a spiral blade and an anti-bending beam, and the anti-deflection beam has a cross-sectional shape perpendicular to the axis of a virtual cylinder surrounding the helical blade, with the axis as the center. It becomes a fan base. Therefore, the anti-bending beam has a relatively high rigidity in a direction perpendicular to the axis of the virtual cylinder surrounding the spiral blade. This bending prevention beam is provided over a plurality of locations in the outer peripheral portion of the spiral blade. Further, two or more deflection preventing beams are provided in the developer conveying section. As a result, it is possible to provide a developing device in which the developer conveying portion is not easily bent.

  Further, in the present invention, since the deflection preventing beam is provided in parallel to the axis of the virtual cylinder surrounding the spiral blade, the volume of the deflection preventing beam can be reduced as compared with the case of being provided in parallel. As a result, more developer can be stored in the developing tank.

  According to the invention, the developer conveying unit includes the spiral blade and the deflection preventing beam, and the deflection preventing beam is provided at a plurality of locations in the outer peripheral portion of the spiral blade. Three or more deflection preventing beams are provided in the developer conveying section. As a result, it is possible to provide a developing device in which the developer conveying portion is not easily bent.

  Further, in the present invention, since the deflection preventing beam is provided in parallel to the axis of the virtual cylinder surrounding the spiral blade, the volume of the deflection preventing beam can be reduced as compared with the case of being provided in parallel. As a result, more developer can be stored in the developing tank.

  Further, according to the present invention, the bending prevention beam is a fan-shaped base having a cross-sectional shape perpendicular to the axis of the virtual cylinder surrounding the spiral blades. This can increase the rigidity of the anti-bending beam in the direction perpendicular to the axis of the virtual cylinder surrounding the spiral blade.

  Further, according to the present invention, the deflection preventing beam is provided so that all the distances from the axis are equal in a cross section perpendicular to the axis of the virtual cylinder surrounding the spiral blade. As a result, the balance when the plurality of deflection preventing beams rotate together with the spiral blades is improved, and the deflection of the developer conveying portion can be further suppressed.

  Further, according to the present invention, the anti-bending beam is provided so that the installation angles formed by the two adjacent anti-bending beams are equal to each other in a cross section perpendicular to the axis of the virtual cylinder surrounding the spiral blade. It is done. As a result, the balance when the plurality of deflection preventing beams rotate together with the spiral blades is improved, and the deflection of the developer conveying portion can be further suppressed.

  Further, according to the present invention, since the developer conveying section includes the developing device that is difficult to bend, the occurrence of image defects can be suppressed.

1 is a schematic diagram illustrating a configuration of an image forming apparatus 100. FIG. 3 is a schematic diagram illustrating a configuration of a toner cartridge 300. FIG. FIG. 3 is a cross-sectional view of the toner cartridge 300 taken along line C-C in FIG. 2. 2 is a schematic diagram illustrating a configuration of a developing device 200. FIG. FIG. 5 is a cross-sectional view of the developing device 200 with AA in FIG. 4 taken along the cutting plane line. FIG. 5 is a cross-sectional view of the developing device 200 taken along line BB in FIG. 4. It is sectional drawing of the 1st spiral blade 202a and the 1st bending prevention beam 202b which make DD of FIG. 6 a cut surface line. It is a figure which shows a modification. 2 is a schematic diagram illustrating a configuration of a developing device 400. FIG. FIG. 10 is a cross-sectional view of the developing device 400 in which EE in FIG. FIG. 10 is a cross-sectional view of the developing device 400 having a section line FF in FIG. 9. It is sectional drawing of the 1st spiral blade 402a and the 1st bending prevention beam 402b which make HH of FIG. 11 a cut surface line. 2 is a schematic diagram illustrating a configuration of a developing device 500. FIG. It is sectional drawing of the developing device 500 which makes II of FIG. 13 a cut surface line. It is sectional drawing of the developing device 500 which makes JJ of FIG. 13 a cut surface line. It is sectional drawing of the 1st spiral blade 502a and the 1st bending prevention beam 502b which make KK of FIG. 15 a cut surface line.

  First, the image forming apparatus 100 including the developing device 200 according to the first embodiment of the present invention will be described. FIG. 1 is a schematic diagram illustrating a configuration of the image forming apparatus 100. The image forming apparatus 100 is a multifunction device having both a copying function, a printer function, and a facsimile function, and forms a full-color or monochrome image on a recording medium according to transmitted image information. The image forming apparatus 100 has three types of printing modes, ie, a copier mode (copy mode), a printer mode, and a facsimile mode, and an operation input from an operation unit (not shown), a personal computer, a portable terminal device, and an information recording medium A print mode is selected by a control unit (not shown) in response to reception of a print job from an external device using the memory device.

  The image forming apparatus 100 includes a toner image forming unit 20, a transfer unit 30, a fixing unit 40, a recording medium supply unit 50, a discharge unit 60, and a control unit unit (not shown). The toner image forming unit 20 includes photosensitive drums 21b, 21c, 21m, and 21y, charging units 22b, 22c, 22m, and 22y, an exposure unit 23, developing devices 200b, 200c, 200m, and 200y, a cleaning unit 25b, 25c, 25m, 25y, toner cartridges 300b, 300c, 300m, 300y, and toner supply pipes 250b, 250c, 250m, 250y. The transfer unit 30 includes an intermediate transfer belt 31, a driving roller 32, a driven roller 33, intermediate transfer rollers 34 b, 34 c, 34 m and 34 y, a transfer belt cleaning unit 35, and a transfer roller 36.

  The photosensitive drum 21, the charging unit 22, the developing device 200, the cleaning unit 25, the toner cartridge 300, the toner supply pipe 250, and the intermediate transfer roller 34 are black (b), cyan (c), magenta included in the color image information. In order to correspond to the image information of each color of (m) and yellow (y), four each are provided. In this specification, when distinguishing each member provided by four according to each color, an alphabet representing each color is added to the end of a number representing each member as a reference symbol, and when each member is collectively referred to Only numerals representing each member are used as reference numerals.

  The photosensitive drum 21 is supported by a drive unit (not shown) so as to be rotatable about an axis, and includes a conductive substrate (not shown) and a photoconductive layer formed on the surface of the conductive substrate. The conductive substrate can take various shapes, and examples thereof include a cylindrical shape, a columnar shape, and a thin film sheet shape. The photoconductive layer is formed of a material that exhibits conductivity when irradiated with light. As the photosensitive drum 21, for example, a cylindrical member (conductive base) formed of aluminum, and amorphous silicon (a-Si), selenium (Se), formed on the outer peripheral surface of the cylindrical member, Alternatively, a film including a thin film (photoconductive layer) made of an organic optical semiconductor (OPC) can be used.

  The charging unit 22, the developing device 200, and the cleaning unit 25 are arranged in this order around the rotation direction of the photosensitive drum 21. The charging unit 22 is disposed below the developing device 200 and the cleaning unit 25 in the vertical direction.

  The charging unit 22 is a device that charges the surface of the photosensitive drum 21 to a predetermined polarity and potential. The charging unit 22 is installed along the longitudinal direction of the photosensitive drum 21 at a position facing the photosensitive drum 21. In the case of the contact charging method, the charging unit 22 is installed in contact with the surface of the photosensitive drum 21. In the case of the non-contact charging method, the charging unit 22 is installed so as to be separated from the surface of the photosensitive drum 21.

  The charging unit 22 is installed around the photosensitive drum 21 together with the developing device 200, the cleaning unit 25, and the like. The charging unit 22 is preferably installed at a position closer to the photosensitive drum 21 than the developing device 200, the cleaning unit 25, and the like. As a result, it is possible to reliably prevent the charging failure of the photosensitive drum 21.

  As the charging unit 22, a brush-type charging device, a roller-type charging device, a corona discharge device, an ion generation device, or the like can be used. The brush type charging device and the roller type charging device are contact charging type charging devices. As the brush type charging device, there are a type using a charging brush and a type using a magnetic brush. The corona discharge device and the ion generator are non-contact charging devices. Corona discharge devices include those using wire-like discharge electrodes, those using sawtooth discharge electrodes, and those using needle-like discharge electrodes.

  The exposure unit 23 is arranged such that light emitted from the exposure unit 23 passes between the charging unit 22 and the developing device 200 and is irradiated on the surface of the photosensitive drum 21. The exposure unit 23 irradiates the charged surface of the photosensitive drums 21b, 21c, 21m, and 21y with laser beams corresponding to the image information of the respective colors, so that each of the photosensitive drums 21b, 21c, 21m, and 21y is exposed. An electrostatic latent image corresponding to the image information of each color is formed on the surface. As the exposure unit 23, for example, a laser scanning unit (LSU) including a laser irradiation unit and a plurality of reflection mirrors can be used. As the exposure unit 23, an LED (Light Emitting Diode) array, a unit in which a liquid crystal shutter and a light source are appropriately combined, or the like may be used.

  The developing device 200 is a device that forms a toner image on the photosensitive drum 21 by developing the electrostatic latent image formed on the photosensitive drum 21 with toner. A toner supply pipe 250 that is a cylindrical member is connected to the upper part of the developing device 200 in the vertical direction. Details of the developing device 200 will be described later.

  The toner cartridge 300 is disposed vertically above the developing device 200 and stores unused toner. A toner supply pipe 250 is connected to the lower part of the toner cartridge 300 in the vertical direction. The toner cartridge 300 supplies toner to the developing device 200 via the toner supply pipe 250. Details of the toner cartridge 300 will be described later.

  The cleaning unit 25 is a member that removes the toner remaining on the surface of the photosensitive drum 21 after the toner image is transferred from the photosensitive drum 21 to the intermediate transfer belt 31 and cleans the surface of the photosensitive drum 21. . As the cleaning unit 25, for example, a plate-like member for scraping off toner and a container-like member for collecting the scraped toner are used.

  According to the toner image forming unit 20, the surface of the photosensitive drum 21 that is uniformly charged by the charging unit 22 is irradiated with laser light corresponding to image information from the exposure unit 23 to form an electrostatic latent image. . A toner image is formed by supplying toner from the developing device 200 to the electrostatic latent image on the photosensitive drum 21. This toner image is transferred to an intermediate transfer belt 31 described later. After the toner image is transferred to the intermediate transfer belt 31, the toner remaining on the surface of the photosensitive drum 21 is removed by the cleaning unit 25.

  The intermediate transfer belt 31 is an endless belt-like member that is disposed above the photosensitive drum 21 in the vertical direction. The intermediate transfer belt 31 is stretched by the driving roller 32 and the driven roller 33 to form a loop-shaped path, and moves in the direction of the arrow B.

  The drive roller 32 is provided so as to be rotatable around its axis by a drive unit (not shown). The drive roller 32 moves the intermediate transfer belt 31 in the direction of the arrow B by its rotation. The driven roller 33 is provided so as to be able to rotate following the rotation of the driving roller 32, and generates a certain tension on the intermediate transfer belt 31 so that the intermediate transfer belt 31 does not loosen.

  The intermediate transfer roller 34 is provided in pressure contact with the photosensitive drum 21 via the intermediate transfer belt 31 and rotatable about its axis by a drive unit (not shown). As the intermediate transfer roller 34, for example, a metal (for example, stainless steel) roller having a diameter of 8 mm to 10 mm on which a conductive elastic member is formed can be used. The intermediate transfer roller 34 is connected to a power source (not shown) for applying a transfer bias, and has a function of transferring the toner image on the surface of the photosensitive drum 21 to the intermediate transfer belt 31.

  The transfer roller 36 is provided in pressure contact with the drive roller 32 via the intermediate transfer belt 31 and is rotatable about an axis by a drive unit (not shown). At the pressure contact portion (transfer nip portion) between the transfer roller 36 and the drive roller 32, the toner image carried and conveyed by the intermediate transfer belt 31 is transferred to a recording medium fed from a recording medium supply unit 50 described later. The

  The transfer belt cleaning unit 35 is provided so as to face the driven roller 33 through the intermediate transfer belt 31 and to be in contact with the toner image carrying surface of the intermediate transfer belt 31. The transfer belt cleaning unit 35 is provided for removing and collecting the toner on the surface of the intermediate transfer belt 31 after the toner image is transferred to the recording medium. If toner remains on the intermediate transfer belt 31 after the toner image is transferred to the recording medium, the residual toner may adhere to the transfer roller 36 due to the movement of the intermediate transfer belt 31. When toner adheres to the transfer roller 36, the toner contaminates the back surface of the recording medium to be transferred next.

  According to the transfer unit 30, when the intermediate transfer belt 31 moves while being in contact with the photosensitive drum 21, a transfer bias having a polarity opposite to the charging polarity of the toner on the surface of the photosensitive drum 21 is applied to the intermediate transfer roller 34. The toner image formed on the surface of the photosensitive drum 21 is transferred onto the intermediate transfer belt 31. The toner images of the respective colors respectively formed on the photosensitive drum 21y, the photosensitive drum 21m, the photosensitive drum 21c, and the photosensitive drum 21b are sequentially transferred onto the intermediate transfer belt 31 in this order, thereby transferring full color. A toner image is formed. The toner image transferred to the intermediate transfer belt 31 is conveyed to the transfer nip portion by the movement of the intermediate transfer belt 31, and transferred to the recording medium at the transfer nip portion. The recording medium on which the toner image is transferred is conveyed to a fixing unit 40 described later.

  The recording medium supply unit 50 includes a paper feed box 51, pickup rollers 52 a and 52 b, transport rollers 53 a and 53 b, registration rollers 54, and a paper feed tray 55. The paper feed box 51 is a container-like member that is provided in the lower part of the image forming apparatus 100 in the vertical direction and stores a recording medium inside the image forming apparatus 100. The paper feed tray 55 is a tray-like member that is provided on the outer wall surface of the image forming apparatus 100 and stores a recording medium outside the image forming apparatus 100. Examples of the recording medium include plain paper, color copy paper, overhead projector sheet, and postcard.

  The pickup roller 52a is a member that takes out recording media stored in the paper feed box 51 one by one and feeds it to the paper transport path A1. The transport rollers 53a are a pair of roller-like members provided so as to be in pressure contact with each other, and transport the recording medium toward the registration rollers 54 in the paper transport path A1. The pickup roller 52b is a member that takes out the recording medium stored in the paper feed tray 55 one by one and feeds it to the paper transport path A2. The transport rollers 53b are a pair of roller-like members provided so as to be in pressure contact with each other, and transport the recording medium toward the registration rollers 54 in the paper transport path A2.

  The registration rollers 54 are a pair of roller-like members provided so as to come into pressure contact with each other, and the toner image carried on the intermediate transfer belt 31 is conveyed to the transfer nip portion of the recording medium fed from the conveyance rollers 53a and 53b. In synchronization with this, the sheet is fed to the transfer nip portion.

  According to the recording medium supply unit 50, the recording medium is transferred from the paper feed box 51 or the paper feed tray 55 to the transfer nip portion in synchronization with the toner image carried on the intermediate transfer belt 31 being conveyed to the transfer nip portion. Then, the toner image is transferred to the recording medium.

  The fixing unit 40 includes a heating roller 41 and a pressure roller 42. The heating roller 41 is controlled to have a predetermined fixing temperature. The pressure roller 42 is a roller that is in pressure contact with the heating roller 41. The heating roller 41 nips the recording medium together with the pressure roller 42 while heating, thereby melting and fixing the toner constituting the toner image on the recording medium. The recording medium on which the toner image is fixed is conveyed to a discharge unit 60 described later.

  The discharge unit 60 includes a conveyance roller 61, a discharge roller 62, and a discharge tray 63. The conveyance roller 61 is a pair of roller-like members provided so as to be in pressure contact with each other in the vertical direction above the fixing unit 40. The conveyance roller 61 conveys the recording medium on which the image is fixed toward the discharge roller 62.

  The discharge roller 62 is a pair of roller-like members provided so as to be in pressure contact with each other. In the case of single-sided printing, the discharge roller 62 discharges the recording medium on which single-sided printing has been completed to the discharge tray 63. In the case of duplex printing, the discharge roller 62 conveys the recording medium on which single-sided printing has been completed to the registration roller 54 via the paper conveyance path A <b> 3, and discharges the recording medium on which duplex printing has been completed to the discharge tray 63. The discharge tray 63 is provided on the upper surface in the vertical direction of the image forming apparatus 100 and stores a recording medium on which an image is fixed.

  Image forming apparatus 100 includes a control unit (not shown). The control unit unit is provided, for example, at an upper part in the vertical direction in the internal space of the image forming apparatus 100, and includes a storage unit, a calculation unit, and a control unit. The storage unit stores various setting values via an operation panel (not shown) arranged on the upper surface in the vertical direction of the image forming apparatus 100, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus 100, external devices, and the like. The image information from is input. A program for executing various processes is written in the storage unit. Examples of the various processes include a recording medium determination process, an adhesion amount control process, and a fixing condition control process.

As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). As the external device, an electric or electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus 100 can be used. For example, a computer, a digital camera, a television receiver, a video recorder , DVD (Digital Versatile
Disc) recorder, HDDVD (High-Definition Digital Versatile Disc) recorder,
Examples include a Blu-ray disc recorder, a facsimile machine, and a mobile terminal device.

  The calculation unit retrieves various data (image formation command, detection result, image information, etc.) written in the storage unit and various processing programs, and performs various determinations. The control unit performs operation control by sending a control signal to each device provided in the image forming apparatus 100 according to the determination result of the calculation unit.

The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor, or the like provided with a central processing unit (CPU). The control unit unit includes a main power source together with the processing circuit, and the power source supplies power not only to the control unit unit but also to each device provided in the image forming apparatus 100.

  FIG. 2 is a schematic diagram illustrating the configuration of the toner cartridge 300. FIG. 3 is a cross-sectional view of the toner cartridge 300 taken along line CC in FIG. The toner cartridge 300 is a device that supplies toner to the developing device 200 via the toner supply pipe 250. The toner cartridge 300 includes a toner storage container 301, a toner scooping member 302, a toner discharge member 303, and a toner discharge container 304.

  The toner storage container 301 is a container-like member having a substantially semi-cylindrical internal space. In the internal space, the toner scooping member 302 is rotatably supported, and unused toner is stored. The toner discharge container 304 is a container-like member having a substantially semi-cylindrical internal space provided along the longitudinal direction of the toner storage container 301, and supports the toner discharge member 303 rotatably in the internal space. The internal space of the toner storage container 301 and the internal space of the toner discharge container 304 communicate with each other via a communication port 305 formed along the longitudinal direction of the toner storage container 301. The toner discharge container 304 has a discharge port 306 formed in the lower part in the vertical direction. A toner supply pipe 250 is connected to the toner discharge container 304 at a discharge port 306.

  The toner scooping member 302 includes a rotation shaft 302a, a base body 302b, and a sliding portion 302c. The rotation shaft 302 a is a columnar member that extends along the longitudinal direction of the toner container 301. The base 302b is a plate-like member extending along the longitudinal direction of the toner container 301, and is attached to the rotating shaft 302a at the center in the width direction and the thickness direction. The sliding portion 302c is a flexible member attached to both ends in the width direction of the base body 302b, and is formed of, for example, polyethylene terephthalate (PET). In the toner pumping member 302, the base body 302b rotates as the rotary shaft 302a rotates about the axis thereof, and as a result, the sliding portions 302c provided at both ends in the width direction of the base body 302b are formed in the toner container 301. By rubbing the wall surface, the toner in the toner container 301 is pumped up to the toner discharge container 304.

  The toner discharge member 303 is a member that conveys the toner in the toner discharge container 304 toward the discharge port 306. The toner discharge member 303 is a so-called auger screw including a toner discharge rotation shaft 303a and a toner discharge blade 303b provided around the toner discharge rotation shaft 303a.

  According to the toner cartridge 300, unused toner in the toner container 301 is pumped up to the toner discharge container 304 by the toner pumping member 302. The toner drawn up in the toner discharge container 304 is conveyed to the discharge port 306 by the toner discharge member 303. The toner conveyed to the discharge port 306 is discharged from the discharge port 306 to the outside of the toner discharge container 304 and is supplied to the developing device 200 via the toner supply pipe 250.

  FIG. 4 is a schematic diagram illustrating the configuration of the developing device 200. FIG. 5 is a cross-sectional view of the developing device 200 taken along line AA in FIG. FIG. 6 is a cross-sectional view of the developing device 200 taken along line BB in FIG. The developing device 200 is a device that develops an electrostatic latent image formed on the surface of the photosensitive drum 21 by supplying toner. The developing device 200 includes a developing tank 201, a first developer conveying unit 202, a second developer conveying unit 203, a developing roller 204, a developing tank cover 205, a doctor blade 206, a partition wall 207, a toner concentration. Detection sensor 208.

  The developing tank 201 is a longitudinal member having an internal space, and stores the developer in the internal space. The developer used in the present invention may be a one-component developer composed only of toner or a two-component developer containing toner and carrier. The developing tank 201 is provided with a developing tank cover 205 at the upper part in the vertical direction. In the internal space, the first developer conveying unit 202, the second developer conveying unit 203, the developing roller 204, the doctor blade 206, the partition wall 207, In addition, a toner concentration detection sensor 208 is provided.

  The developing roller 204 is a magnet roller that rotates around an axis by a drive unit (not shown), and supports the developer in the developing tank 201 on the surface, and supplies toner contained in the supported developer to the photosensitive drum 21. . A power supply (not shown) is connected to the developing roller 204, and a developing bias voltage is applied. The toner carried on the developing roller 204 moves to the photosensitive drum 21 in the vicinity of the photosensitive drum 21 by electrostatic force due to the developing bias voltage.

  The doctor blade 206 is a plate-like member extending in the axial direction of the developing roller 204, and is provided so that one end in the width direction is fixed to the developing tank 201 and the other end has a gap with respect to the surface of the developing roller 204. It is done. The doctor blade 206 is provided with a gap with respect to the surface of the developing roller 204, thereby regulating the amount of developer carried on the developing roller 204 to a predetermined amount. As the material of the doctor blade 206, stainless steel, aluminum, synthetic resin, or the like can be used.

  The partition wall 207 is a longitudinal member extending along the longitudinal direction of the developing tank 201 at a substantially central portion of the developing tank 201. The partition wall 207 is provided between the lower part in the vertical direction of the developing tank 201 and the developing tank cover 205, and is provided so that both ends in the longitudinal direction are separated from the inner wall surface of the developing tank 201. The partition wall 207 divides the internal space of the developing tank 201 into a first conveyance path Q, a second conveyance path P, a first communication path S, and a second communication path R.

  The second transport path P is a space that extends along the longitudinal direction of the partition wall 207 and that accommodates the developing roller 204. The first transport path Q is a space facing the second transport path P with the partition wall 207 interposed therebetween. The first communication path S is a space that communicates the first transport path Q and the second transport path P at one longitudinal end 207 a of the partition wall 207. The second communication path R is a space that communicates the first transport path Q and the second transport path P at the other longitudinal end 207 b of the partition wall 207.

  The developing tank cover 205 is detachably provided above the developing tank 201 in the vertical direction. A supply port 205 a is formed in the developing tank cover 205. The supply port 205a is formed at a position facing the second communication path R above the first transport path Q in the vertical direction. A toner supply pipe 250 is connected to the developing tank cover 205 at a supply port 205a. The toner stored in the toner cartridge 300 is supplied into the developing tank 201 through the toner supply pipe 250 and the supply port 205a.

  The first developer conveyance unit 202 is provided in the first conveyance path Q, and includes a first spiral blade 202a, a first deflection preventing beam 202b, a first support member 202c, and a first gear 202d. The first spiral blade 202a extends in the longitudinal direction of the partition wall 207, and is supported by the two first support members 202c at both ends in the longitudinal direction. Of the two first support members 202c, the first support member 202c on the second communication path R side is rotatably supported by the inner wall of the developing tank 201. Of the two first support members 202 c, the first support member 202 c on the first communication path S side is connected to the first gear 202 d outside the developing tank 201.

The first spiral blade 202a has a shape surrounding the side surface of the virtual cylinder, and is centered on the axis of the virtual cylinder by a drive unit such as a motor via the first support member 202c and the first gear 202d. rotational movement in the rotational direction _{G 1.} The developer stored in the first transport path Q is transported in the transport direction Y by the rotational movement of the first spiral blade 202a. The transport direction Y is a direction from the second communication path R toward the first communication path S.

  The second developer transport unit 203 is provided in the second transport path P, and includes a second spiral blade 203a, a second deflection preventing beam 203b, a second support member 203c, and a second gear 203d. The second spiral blade 203a extends in the longitudinal direction of the partition wall 207, and is supported by two second support members 203c at both ends in the longitudinal direction. Of the two second support members 203c, the second support member 203c on the second communication path R side is rotatably supported by the inner wall of the developing tank 201. Of the two second support members 203 c, the second support member 203 c on the first communication path S side is connected to the second gear 203 d outside the developing tank 201.

The second spiral blade 203a has a shape surrounding the side surface of the virtual cylinder, and is centered on the axis of the virtual cylinder by a driving unit such as a motor via the second support member 203c and the second gear 203d. rotational movement in the rotational direction _{G 2.} The developer stored in the second transport path P is transported in the transport direction X by the rotational movement of the second spiral blade 203a. The transport direction X is a direction from the first communication path S to the second communication path R, and is opposite to the transport direction Y.

  In the present embodiment, the first developer transport unit 202 and the second developer transport unit 203 are configured in the same shape. However, the first developer transport unit 202 and the second developer transport unit 203 do not have to have the same shape. For example, one of the first developer transport unit 202 and the second developer transport unit 203 is used. May have an auger screw shape. The first developer conveyance unit 202 will be described in detail later.

  As described above, the supply port 205a of the developing tank cover 205 is formed at a position facing the second communication path R in the vertical direction above the first transport path Q. Accordingly, unused toner in the toner cartridge 300 is first supplied upstream in the transport direction Y in the first transport path Q, and then transported downstream in the transport direction Y by the first developer transport unit 202. It will be.

  The toner concentration detection sensor 208 is mounted on the lower part in the vertical direction of the developing tank 201 and below the second developer transport unit 203 in the vertical direction so that the sensor surface is exposed to the second transport path P. The toner concentration detection sensor 208 is electrically connected to a toner concentration control unit (not shown).

  The toner density control unit performs control to rotate the toner discharge member 303 and supply the toner into the developing tank 201 in accordance with the toner density detection result detected by the toner density detection sensor 208. More specifically, the toner density control unit determines whether or not the toner density detection result by the toner density detection sensor 208 is lower than a predetermined set value, and rotates the toner discharge member 303 when it is determined that the toner density detection result is low. A control signal is sent to the drive unit to rotate the toner discharge member 303 for a predetermined period.

  The toner concentration detection sensor 208 is connected to a power source (not shown). The power supply applies to the toner concentration detection sensor 208 a drive voltage for driving the toner concentration detection sensor 208 and a control voltage for outputting the toner concentration detection result to the toner concentration control unit. Application of a voltage to the toner concentration detection sensor 208 by the power supply is controlled by a control unit (not shown).

  As the toner concentration detection sensor 208, a general toner concentration detection sensor can be used. For example, a transmitted light detection sensor, a reflected light detection sensor, a magnetic permeability detection sensor, or the like can be used. Among these toner concentration detection sensors, it is preferable to use a magnetic permeability detection sensor. Examples of the magnetic permeability detection sensor include TS-L (trade name, manufactured by TDK Corporation), TS-A (trade name, manufactured by TDK Corporation), TS-K (trade name, manufactured by TDK Corporation), and the like. It is done.

  According to such a developing device 200, the developer is circulated and conveyed in the order of the first conveyance path Q, the first communication path S, the second conveyance path P, and the second communication path R in the developing tank 201. The A part of the developer thus circulated and conveyed is carried on the surface of the developing roller 204 in the second conveyance path P, and the toner in the carried developer moves to the photosensitive drum 21. Are consumed sequentially. When the toner concentration detection sensor 208 detects that a predetermined amount of toner has been consumed, unused toner is supplied from the toner cartridge 300 to the first transport path Q. The supplied toner diffuses into the developer while being transported in the first transport path Q.

  Hereinafter, the first developer conveyance unit 202 will be described in detail. Note that the second developer transport unit 203 has the same configuration as the first developer transport unit 202, and thus description thereof is omitted. As described above, the first developer transport unit 202 includes the first spiral blade 202a, the first deflection preventing beam 202b, the first support member 202c, and the first gear 202d.

  The first spiral blade 202a, the first deflection preventing beam 202b, the first support member 202c, and the first gear 202d are, for example, polyethylene, polypropylene, high impact polystyrene, ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin), or the like. Formed from the material. When the materials of the first spiral blade 202a, the first deflection preventing beam 202b, the first support member 202c, and the first gear 202d are the same, it is preferable that the first developer transport unit 202 is integrally formed.

FIG. 7 is a cross-sectional view of the first spiral blade 202a and the first deflection preventing beam 202b having a cut surface line DD in FIG. The first spiral blade 202a is a member having a shape surrounding the side surface of the imaginary cylindrical shape when viewed in the direction of the axis N ₁ of the virtual cylinder is substantially annular. More specifically, the first spiral blade 202a is a member having a predetermined thickness having a surface formed by the locus of the line segment when the line segment is moved along the spiral. Here, the “spiral line” is a continuous space curve on the side surface of the virtual cylinder, and the axial direction of the virtual cylinder while proceeding in one direction of the circumferential direction of the virtual cylinder. It is the space curve which progresses to one direction.

Twice the value of the distance from the axis _{N 1} to a point on the farthest first spiral blade 202a, referred to as the outer diameter _{L 1} of the first spiral blade 202a. Further, the value of twice the distance from the axis _{N 1} to the closest point on the first spiral blade 202a, referred to as the inner diameter _{L 2} of the first spiral blade 202a. Outer diameter _{L 1,} for example can be set as appropriate within a range of 10 mm to 30 mm, an inner diameter _{L 2} it is, for example, can be appropriately set within a range of 0Mm～10mm. In the case the developing device 200 is small, the outer diameter _{L 1} is set within a range of 10 mm to 20 mm, an inner diameter _{L 2} is set within the range of 0Mm～5mm.

The thickness L3 of the first spiral blade 202a can be set as appropriate within a range of 1 mm to ₃ mm. When the developing device 200 is small, the thickness _{L 3} of the first spiral blade 202a is set within the range of 1 mm to 2 mm.

In the first spiral blade 202a, the distance from the axis _{N 1} is a set of 40% to 50% and becomes part of the outer diameter _{L 1,} referred to as a peripheral portion _{T 1} of the first spiral blade 202a. Incidentally, the outer peripheral portion _{T 1} of the first spiral blade 202a becomes spiral-shaped. Broken line in FIG. 7 represents the boundary between the peripheral portion T ₁ and the other portion. In this embodiment, the outer peripheral portion _{T 1} of the first spiral blade 202a, the recess _{W 1} is formed. Recess W _1, in the outer peripheral portion T ₁ of the first spiral blade 202a, are formed at a plurality of locations on a straight line parallel to the axis N _1. The recess _{W 1,} the first deflection preventing beam 202b is provided.

First deflection preventing beam 202b is a member that the first spiral blade 202a is prevented from flexing in a direction perpendicular to the axis N _1. First deflection preventing beam 202b is a columnar member provided parallel to the axis N _1, through the space surrounded by the concave portion W _1, is connected to the concave portion W _1. Since the recess _{W 1} in a plurality of locations on a straight line parallel to the axis _{N 1} is formed in the outer peripheral portion _{T 1} of the first spiral blade 202a, the first deflection preventing beam 202b is an outer peripheral portion of the first spiral blade 202a It will be provided in a straight line over a plurality of locations in the T _1.

  In the present embodiment, two first deflection preventing beams 202b having the same shape are provided. The number of the first deflection preventing beams 202b may be an arbitrary number of two or more, but if the number of the first deflection preventing beams 202b is too large, the total value of the surface areas of the first deflection preventing beams 202b is increased. As a result, the friction generated between the first deflection preventing beam 202b and the developer increases during the rotational movement of the first spiral blade 202a. Therefore, the number of the first bending prevention beams 202b is preferably 2 or more and 6 or less.

  The length in the longitudinal direction of the first deflection preventing beam 202b is 70% or more of the length in the longitudinal direction of the entire first spiral blade 202a, and more preferably 90% or more. This can further suppress the bending of the first spiral blade 202a.

The shape of the cross section perpendicular to the axis N ₁ of the first deflection preventing beam 202b is a sector table about the axis N _1. The sector base is a shape obtained by removing a sector shape whose center and central angle coincide with each other and smaller than the sector shape. The center and center angle of the sector base are the center and center angle of the original sector. Sector base central angle of the axis N ₁ in the form of a vertical cross section of a first deflection preventing beam 202b is preferably 5 ° or to 45 °, further preferably 30 ° or less than 15 °. In the present embodiment, the center angle theta ₁ of the fan base is 25 °.

By the fan-shaped base cross section perpendicular shape to the axis N ₁ of the first deflection preventing beam 202b, it is possible to increase the rigidity of the first deflection preventing beam 202b, upon rotational movement of the first spiral blade 202a In addition, the friction generated between the first deflection preventing beam 202b and the developer can be reduced. Incidentally, the vertical cross section of a shape to the axis N ₁ of the first deflection preventing beam 202b, when the circle having the same area as the fan-shaped stand instead of the sector table, the rigidity of the first deflection preventing beam 202b becomes lower .

Area of the cross section perpendicular to the axial line _{N 1} of the first deflection preventing beam 202b ^can be appropriately set within a range of 1 mm 2 to 20 mm ^2. When the developing device 200 is small, the area of the cross section perpendicular to the axis _{N 1} of the first deflection preventing beam 202b ^is set within the range of 1 mm 2 to 10 mm ^2.

In this embodiment, two first deflection preventing beam 202b, in a section perpendicular to the axis N _1, provided as the distance from said axis N ₁ equal. Distance between the first deflection preventing beam 202b to the axis _{N 1} is more particularly, the distance between the centroid _{Z 1} and the axis _{N 1} of the cross-section shape of the first deflection preventing beam 202b. With this configuration, the balance when the first bending prevention beam 202b rotates together with the first spiral blade 202a is improved, and the bending of the first developer transport unit 202 can be further suppressed.

In a cross section perpendicular to the axis N _1, referred to as the angle between the two first deflection preventing beam 202b adjacent the said axis N ₁ installation angle. Installation angle, more particularly, the centroid _{Z 1} of the line segment connecting one of the centroid _{Z 1} of the first deflection preventing beam 202b and the axis _{N 1,} another first deflection preventing beam 202b and the axis _{N 1} Is an angle formed by a line segment connecting the two and the angle between 0 ° and 180 ° or less. When the installation angle in this embodiment is σ, the installation angle σ is 180 °.

  The 1st spiral blade 202a is provided with the 1st support member 202c in the longitudinal direction both ends. The first support member 202c of this embodiment is a columnar member. In the longitudinal direction of the first spiral blade 202a, the length of the portion where one first support member 202c is provided is 15% or more and 40% or less of the length in the longitudinal direction of the entire first spiral blade 202a. Therefore, in the longitudinal direction of the first spiral blade 202a, the portion where the first support member 202c is not provided, that is, the length of the central portion in the longitudinal direction of the first spiral blade 202a is the longitudinal direction of the entire first spiral blade 202a. It is 60% or more and 85% or less of the length.

The outer diameter of the first support member 202c may be set to the same length as the inner diameter _{L 2} of the first spiral blade 202a, also, for example, it can be appropriately set within a range of 5 mm to 15 mm. The first support member 202c is by a driving section (not shown), in 60Rpm～180rpm, it rotates in the rotational direction _{G 1.}

  In the present embodiment, nothing is provided inside the first spiral blade 202a at the center in the longitudinal direction of the first spiral blade 202a. The space inside the first spiral blade 202a of this embodiment is used as a developer moving space. That is, the developer present in the space inside the first spiral blade 202a is not pushed by the first spiral blade 202a, and therefore does not proceed in the transport direction Y and tries to stay there. As a result, the developer present in the space inside the first spiral blade 202a appears to advance in the transport direction X with reference to the developer traveling in the transport direction Y. In the present embodiment, the two developer flows in the first transport path Q cause the developer to be agitated by friction between the developers, thereby eliminating the unevenness of the toner in the developing tank 201. .

  In the present embodiment, only the first bending prevention beam 202b is provided at the longitudinal center of the first spiral blade 202a. When the material of the first spiral blade 202a and the material of the first deflection preventing beam 202b are the same hardness, or when the material of the first deflection preventing beam 202b is harder than the material of the first spiral blade 202a, the first In the deflection preventing beam 202b, the volume of the portion corresponding to the longitudinal center portion of the first spiral blade 202a is preferably 5% or more and 15% or less of the volume of the longitudinal center portion of the first spiral blade 202a. By setting it to 5% or more, the first spiral blade 202a becomes difficult to bend, and by setting it to 15% or less, the occupied volume of the first developer transport unit 202 in the developing tank 201 can be reduced, and as a result, more The developer can be stored in the developing tank 201.

  As another embodiment of the present invention, a columnar member may be provided inside the first spiral blade 202a at the center in the longitudinal direction of the first spiral blade 202a. In this case, when the material of the columnar member, the material of the first spiral blade 202a, and the material of the first deflection preventing beam 202b are the same hardness, or the first deflection preventing beam than the material of the first spiral blade 202a. When the material of 202b and the cylindrical member is hard, the sum of the volume of the cylindrical member and the volume of the portion corresponding to the central portion in the longitudinal direction of the first spiral blade 202a in the first deflection preventing beam 202b is the first spiral blade. It is preferable that it is 7% or more and 15% or less of the volume of the central portion in the longitudinal direction of 202a. By setting it to 7% or more, the first spiral blade 202a becomes difficult to bend, and by setting it to 15% or less, the occupied volume of the first developer transport unit 202 in the developing tank 201 can be reduced, and as a result, more The developer can be stored in the developing tank 201.

  In addition, the conventional developer transport unit includes a cylindrical rotary shaft member and a spiral blade surrounding the rotary shaft member. In order to maintain the same rigidity when the developer transport unit is reduced in diameter, The volume of the rotating shaft member needs to be 20% or more and 30% or less of the volume of the spiral blade.

In the first developing agent transport unit 202 thus configured, first deflection preventing beam 202b, since the shape of the cross section perpendicular to the axis N ₁ is a fan-shaped stand around the axial line N _1, the the first deflection preventing beam 202b, the rigidity in the direction perpendicular to the axis N ₁ is relatively high. The first deflection preventing beam 202b, in the outer peripheral portion _{T 1} of the first spiral blade 202a is provided over a plurality of positions, further, the first deflection preventing beam 202b is provided two in the first developer conveying portion 202 It is done. Therefore, the first developer transport unit 202 is less likely to bend than the conventional developer transport unit.

  The conventional developer transport unit includes a spiral blade and a relatively thick rotating shaft member. However, the first developer transport unit 202 is not necessarily provided with a rotating shaft member, and is provided with a rotating shaft member. Can also be made relatively thin. For example, in the conventional developer transport unit, the value of the outer diameter of the rotating shaft member / the outer diameter of the spiral blade × 100 is 20% or more and 50% or less, whereas in the present invention, the outer diameter of the rotating shaft member is / The value of spiral blade outer diameter × 100 can be 0% or more and less than 20%.

The first deflection preventing beam 202b is so provided in parallel with the axis N _1, as compared with the case of provision of non-parallel, the volume of the first deflection preventing beam 202b is small. Therefore, more developer can be stored in the developing tank 201.

  In the present embodiment, each first deflection preventing beam 202b is one continuous member. However, as a modification of the present embodiment, one first deflection preventing beam 202b is composed of a plurality of pieces. Also good.

FIG. 8 is a diagram showing a modification. In the modified example, the first deflection preventing beam 202b includes a plurality of pieces 202e. Further, in the modification, the concave portion W ₁ is not provided in the outer peripheral portion of the first spiral blade 202a, each fragment 202e is connected to the surface of the outer peripheral portion of the first spiral blade 202a. More specifically, in the modification, each fragment 202e, in the outer peripheral portion of the first spiral blade 202a, which connects the first surface and the other surface, straight parallel to each fragment 202e is the axis N ₁ As a result, one first deflection preventing beam 202b is formed. In the modified example configured as described above, the bending is suppressed as compared with the conventional developer transport unit.

  Next, the developing device 400 according to the second embodiment of the present invention will be described. FIG. 9 is a schematic diagram illustrating a configuration of the developing device 400. FIG. 10 is a cross-sectional view of the developing device 400 taken along line E-E in FIG. FIG. 11 is a cross-sectional view of the developing device 400 taken along the line F-F in FIG. The developing device 400 is provided in the image forming apparatus 100 instead of the developing device 200, and is a device that develops the electrostatic latent image formed on the surface of the photosensitive drum 21 by supplying toner. The developing device 400 includes a developing tank 201, a first developer conveying unit 402, a second developer conveying unit 403, a developing roller 204, a developing tank cover 205, a doctor blade 206, a partition wall 207, a toner concentration. Detection sensor 208.

  In the developing device 200, the developing device 200 includes a first developer transport unit 402 instead of the first developer transport unit 202, and a second developer transport unit 403 instead of the second developer transport unit 203. Is. Accordingly, the developing tank 201, the developing roller 204, the developing tank cover 205, the doctor blade 206, the partition wall 207, and the toner concentration detection sensor 208, which are members common to the first embodiment and the second embodiment, will be described. Is omitted. As another embodiment of the present invention, in the developing device 200, a first developer transport unit 402 is provided instead of the first developer transport unit 202, and the second developer transport unit 203 is left as it is. There may be.

  The first developer conveyance unit 402 is provided in the first conveyance path Q, and includes a first spiral blade 402a, a first deflection preventing beam 402b, a first support member 402c, and a first gear 402d. The first spiral blade 402a extends in the longitudinal direction of the partition wall 207, and is supported by the two first support members 402c at both ends in the longitudinal direction. Of the two first support members 402c, the first support member 402c on the second communication path R side is rotatably supported by the inner wall of the developing tank 201. Of the two first support members 402c, the first support member 402c on the first communication path S side is connected to the first gear 402d outside the developing tank 201.

The first spiral blade 402a has a shape surrounding the side surface of the virtual cylinder, and is centered on the axis of the virtual cylinder by a drive unit such as a motor via the first support member 402c and the first gear 402d. rotational movement in the rotational direction _{G 1.} The developer stored in the first transport path Q is transported in the transport direction Y by the rotational movement of the first spiral blade 402a.

  The second developer transport unit 403 is provided in the second transport path P, and includes a second spiral blade 403a, a second deflection preventing beam 403b, a second support member 403c, and a second gear 403d. The second spiral blade 403a extends in the longitudinal direction of the partition wall 207, and is supported by the two second support members 403c at both ends in the longitudinal direction. Of the two second support members 403c, the second support member 403c on the second communication path R side is rotatably supported on the inner wall of the developing tank 201. Of the two second support members 403c, the second support member 403c on the first communication path S side is connected to the second gear 403d outside the developing tank 201.

The second spiral blade 403a has a shape surrounding the side surface of the virtual cylinder, and the axis of the virtual cylinder is centered by a driving unit such as a motor via the second support member 403c and the second gear 403d. rotational movement in the rotational direction _{G 2.} The developer stored in the second transport path P is transported in the transport direction X by the rotational movement of the second spiral blade 403a.

  In the present embodiment, the first developer transport unit 402 and the second developer transport unit 403 are configured in the same shape. However, the first developer transport unit 402 and the second developer transport unit 403 may not have the same shape. For example, one of the first developer transport unit 402 and the second developer transport unit 403 is used. May have an auger screw shape.

  Hereinafter, the first developer conveyance unit 402 will be described in detail. The second developer transport unit 403 has the same configuration as the first developer transport unit 402, and thus the description thereof is omitted. As described above, the first developer transport unit 402 includes the first spiral blade 402a, the first deflection preventing beam 402b, the first support member 402c, and the first gear 402d.

  The first spiral blade 402a, the first deflection preventing beam 402b, the first support member 402c, and the first gear 402d are made of, for example, a material such as polyethylene, polypropylene, high impact polystyrene, or ABS resin. When the first spiral blade 402a, the first deflection preventing beam 402b, the first support member 402c, and the first gear 402d are made of the same material, it is preferable that the first developer transport unit 402 is integrally formed.

FIG. 12 is a cross-sectional view of the first spiral blade 402a and the first deflection preventing beam 402b having a cut surface line HH in FIG. The first spiral blade 402a is a member having a shape surrounding the side surface of the imaginary cylindrical shape when viewed in the direction of the axis N ₂ of said imaginary cylinder is substantially annular. More specifically, the first spiral blade 402a is a member having a predetermined thickness having a surface formed by a locus of the line segment when the line segment is moved along the spiral.

A value twice the distance from the axis N ₂ to a point on the first spiral blade 402a farthest from the axis N ₂ is referred to as an outer diameter L ₄ of the first spiral blade 402a. A value twice the distance from the axis N ₂ to the nearest point on the first spiral blade 402a is referred to as an inner diameter L ₅ of the first spiral blade 402a. Outer diameter _{L 4} are, for example, it can be appropriately set within a range of 10 mm to 30 mm, an inner diameter _{and L 5,} for example, can be appropriately set within a range of 0Mm～10mm. When the developing device 400 is small, the outer diameter L ₄ is set within a range of 10 mm to 20 mm, and the inner diameter L ₅ is set within a range of 0 mm to ₅ mm.

The thickness _{L 6} of the first spiral blade 402a can be appropriately set within a range of 1 mm to 3 mm. When the developing device 400 is small, the thickness _{L 6} of the first spiral blade 402a is set within the range of 1 mm to 2 mm.

In the first spiral blade 402a, a set of partial distances from the axis _{N 2} is equal to or less than 50% 40% of the outer diameter _{L 4,} referred to as outer peripheral portion _{T 2} of the first spiral blade 402a. Incidentally, the outer peripheral portion _{T 2} of the first spiral blade 402a becomes spiral-shaped. Broken line in FIG. 12 represents the boundary between the outer peripheral portion T ₂ and other parts. In this embodiment, the outer peripheral portion T ₂ of the first spiral blade 402a, the hole W ₂ is formed. Hole W _2, in the outer peripheral portion T ₂ of the first spiral blade 402a, are formed at a plurality of locations on a straight line parallel to the axis N _2. The hole _{W 2,} first deflection preventing beam 402b is provided.

First deflection preventing beam 402b is a member that the first spiral blade 402a is prevented from flexing in a direction perpendicular to the axis N _2. First deflection preventing beam 402b is a columnar member provided parallel to the axis N _2, through the space surrounded by the hole portion W _2, is connected to the hole portion W _2. Since the hole portion _{W 2} in a plurality of locations on a line parallel to the axis _{N 2} are formed in the outer peripheral portion _{T 2} of the first spiral blade 402a, the first deflection preventing beam 402b is an outer periphery of the first spiral blade 402a It will be provided in a straight line over a plurality of locations in the portion T _2.

  In the present embodiment, three first deflection preventing beams 402b having the same shape are provided. The number of the first deflection preventing beams 402b may be an arbitrary number of three or more. However, when the number of the first deflection preventing beams 402b is too large, the total value of the surface areas of the first deflection preventing beams 402b is increased. As a result, the friction generated between the first deflection preventing beam 402b and the developer increases during the rotational movement of the first spiral blade 402a. Therefore, the number of the first bending prevention beams 402b is preferably 3 or more and 6 or less.

  The length in the longitudinal direction of the first deflection preventing beam 402b is 70% or more of the length in the longitudinal direction of the entire first spiral blade 402a, and more preferably 90% or more. Thereby, it is possible to further suppress the bending of the first spiral blade 402a.

The shape of the cross section perpendicular to the axis N ₂ of the first deflection preventing beam 402b is circular. As described in the first embodiment, the first deflection preventing beam 402b having a circular cross-sectional shape is lower in rigidity than the first deflection preventing beam 402b having a sectoral cross section. However, in this embodiment, since the three first bending prevention beams 402b are provided, the bending of the first spiral blade 402a is suppressed.

Area of the cross section perpendicular to the axial line _{N 2} of the first deflection preventing beam 402b ^can be appropriately set within a range of 1 mm 2 to 20 mm ^2. When the developing device 400 is small, the area of the cross section perpendicular to the axis N ₂ of the first bending prevention beam 402 ^b is set within a range of 1 mm ^{2 to} 10 mm ² .

In this embodiment, three first deflection preventing beam 402b, in a section perpendicular to the axis N _2, is provided so that a distance from said axis N ₂ equal. Distance between the first deflection preventing beam 402b to the axis _{N 2} is more particularly, the distance between the centroid _{Z 2} and the axis _{N 2} cross-sectional shapes of the first deflection preventing beam 402b. With this configuration, the balance when the first bending prevention beam 402b rotates together with the first spiral blade 402a is improved, and the bending of the first developer transport unit 402 can be further suppressed.

In a cross section perpendicular to the axis N _2, referred to as the angle between the two first deflection preventing beam 402b adjacent the axial line N ₂ installation angle. Installation angle, more particularly, the centroid _{Z 2} one of the line segment connecting the centroid _{Z 2} and the axis _{N 2} of the first deflection preventing beam 402b, the other of the first deflection preventing beam 402b and the axis _{N 2} Is an angle formed by a line segment connecting the two and the angle between 0 ° and 180 ° or less. In the present embodiment, since there are three first bending prevention beams 402b, the installation angle is three. When the three installation angles in the present embodiment are σ ₁ , σ ₂ , and σ ₃ , the three installation angles σ ₁ , σ ₂ , and σ ₃ are all 120 °. Thus, in a cross section perpendicular to the axis N _2, a plurality of first bending prevention beam 402b is provided to installation angle formed by the two first deflection preventing beam 402b adjacent to the said axis N ₂ is equal all As a result, the balance when the plurality of first bending prevention beams 402b rotate together with the first spiral blade 402a is improved, and the bending of the first developer conveying unit 402 can be further suppressed.

  The first spiral blade 402a is provided with a first support member 402c at both ends in the longitudinal direction. The first support member 402c of this embodiment is a columnar member. In the longitudinal direction of the first spiral blade 402a, the length of the portion where one first support member 402c is provided is not less than 15% and not more than 40% of the length in the longitudinal direction of the entire first spiral blade 402a. Therefore, in the longitudinal direction of the first spiral blade 402a, the portion where the first support member 402c is not provided, that is, the length of the central portion in the longitudinal direction of the first spiral blade 402a is the longitudinal direction of the entire first spiral blade 402a. It is 60% or more and 85% or less of the length.

The outer diameter of the first support member 402c may be set to the same length as the inner diameter _{L 5} of the first spiral blade 402a, also, for example, it can be appropriately set within a range of 5 mm to 15 mm. The first support member 402c is by a driving section (not shown), in 60Rpm～180rpm, it rotates in the rotational direction _{G 1.}

  In the present embodiment, nothing is provided inside the first spiral blade 402a at the center in the longitudinal direction of the first spiral blade 402a. The space inside the first spiral blade 402a of this embodiment is used as a developer moving space. That is, the developer present in the space inside the first spiral blade 402a is not pushed by the first spiral blade 402a, and therefore does not proceed in the transport direction Y and tries to stay there. As a result, the developer present in the space inside the first spiral blade 402a appears to advance in the transport direction X when the developer traveling in the transport direction Y is used as a reference. In the present embodiment, the two developer flows in the first transport path Q cause the developer to be agitated by friction between the developers, thereby eliminating the unevenness of the toner in the developing tank 201. .

  In the present embodiment, only the first deflection preventing beam 402b is provided at the longitudinal center of the first spiral blade 402a. When the material of the first spiral blade 402a and the material of the first deflection preventing beam 402b are the same hardness, or when the material of the first deflection preventing beam 402b is harder than the material of the first spiral blade 402a, the first In the bending prevention beam 402b, the volume of the portion corresponding to the central portion in the longitudinal direction of the first spiral blade 402a is preferably 5% or more and 15% or less of the volume of the central portion in the longitudinal direction of the first spiral blade 402a. By setting it to 5% or more, the first spiral blade 402a becomes difficult to bend, and by setting it to 15% or less, the occupied volume of the first developer transport unit 402 in the developing tank 201 can be reduced, and as a result, more The developer can be stored in the developing tank 201.

  As another embodiment of the present invention, a columnar member may be provided inside the first spiral blade 402a at the center in the longitudinal direction of the first spiral blade 402a. In this case, when the material of the columnar member, the material of the first spiral blade 402a, and the material of the first deflection preventing beam 402b are the same hardness, or the first deflection preventing beam than the material of the first spiral blade 402a. When the material of 402b and the columnar member is hard, the sum of the volume of the columnar member and the volume of the portion corresponding to the central portion in the longitudinal direction of the first spiral blade 402a in the first deflection preventing beam 402b is the first spiral blade. It is preferably 7% or more and 15% or less of the volume of the central portion in the longitudinal direction of 402a. By setting the ratio to 7% or more, the first spiral blade 402a becomes difficult to bend, and by setting the ratio to 15% or less, the occupied volume of the first developer conveying unit 402 in the developing tank 201 can be reduced, and as a result The developer can be stored in the developing tank 201.

In thus configured first developer conveying unit 402, the first deflection preventing beam 402b is provided over a plurality of locations at the outer portion T ₂ of the first spiral blade 402a. Three first deflection preventing beams 402 b are provided in the first developer conveying unit 402. Therefore, the first developer transport unit 402 is less likely to bend than the conventional developer transport unit.

  Although the conventional developer transport unit includes a spiral blade and a relatively thick rotating shaft member, the first developer transport unit 402 is not necessarily provided with a rotating shaft member, and is provided with a rotating shaft member. Can also be made relatively thin. For example, in the conventional developer transport unit, the value of the outer diameter of the rotating shaft member / the outer diameter of the spiral blade × 100 is 20% or more and 50% or less, whereas in the present invention, the outer diameter of the rotating shaft member is / The value of spiral blade outer diameter × 100 can be 0% or more and less than 20%.

The first deflection preventing beam 402b is so provided in parallel with the axis N _2, as compared with the case of provision of non-parallel, the volume of the first deflection preventing beam 402b is small. Therefore, more developer can be stored in the developing tank 201.

  In the present embodiment, each first deflection preventing beam 402b is one continuous member. However, as a modification of the present embodiment, one first deflection preventing beam 402b is composed of a plurality of pieces. Also good.

  Next, the developing device 500 according to the third embodiment of the present invention will be described. FIG. 13 is a schematic diagram illustrating a configuration of the developing device 500. FIG. 14 is a cross-sectional view of the developing device 500 taken along line II in FIG. FIG. 15 is a cross-sectional view of the developing device 500 with JJ in FIG. The developing device 500 is provided in the image forming apparatus 100 in place of the developing device 200, and is a device that develops the electrostatic latent image formed on the surface of the photosensitive drum 21 by supplying toner. The developing device 500 includes a developing tank 201, a first developer conveying unit 502, a second developer conveying unit 503, a developing roller 204, a developing tank cover 205, a doctor blade 206, a partition wall 207, and a toner concentration. Detection sensor 208.

  The developing device 500 includes a first developer transport unit 502 instead of the first developer transport unit 202 and a second developer transport unit 503 instead of the second developer transport unit 203 in the developing device 200. Is. Therefore, the developing tank 201, the developing roller 204, the developing tank cover 205, the doctor blade 206, the partition wall 207, and the toner concentration detection sensor 208, which are members common to the first embodiment and the third embodiment, are described. Is omitted. As another embodiment of the present invention, in the developing device 200, a first developer transport unit 502 is provided instead of the first developer transport unit 202, and the second developer transport unit 203 is left as it is. There may be.

  The first developer conveyance unit 502 is provided in the first conveyance path Q, and includes a first spiral blade 502a, a first deflection preventing beam 502b, a first support member 502c, and a first gear 502d. The first spiral blade 502a extends in the longitudinal direction of the partition wall 207, and is supported by two first support members 502c at both ends in the longitudinal direction. Of the two first support members 502c, the first support member 502c on the second communication path R side is rotatably supported by the inner wall of the developing tank 201. Of the two first support members 502 c, the first support member 502 c on the first communication path S side is connected to the first gear 502 d outside the developing tank 201.

The first spiral blade 402a has a shape surrounding the side surface of the virtual cylinder, and is centered on the axis of the virtual cylinder by a drive unit such as a motor via the first support member 502c and the first gear 502d. rotational movement in the rotational direction _{G 1.} The developer stored in the first transport path Q is transported in the transport direction Y by the rotational movement of the first spiral blade 502a.

  The second developer transport unit 503 is provided in the second transport path P, and includes a second spiral blade 503a, a second deflection preventing beam 503b, a second support member 503c, and a second gear 503d. The second spiral blade 503a extends in the longitudinal direction of the partition wall 207, and is supported by the two second support members 503c at both ends in the longitudinal direction. Of the two second support members 503c, the second support member 503c on the second communication path R side is rotatably supported by the inner wall of the developing tank 201. Of the two second support members 503c, the second support member 503c on the first communication path S side is connected to the second gear 503d outside the developing tank 201.

The second spiral blade 503a has a shape surrounding the side surface of the virtual cylinder, and the axis of the virtual cylinder is centered by a driving unit such as a motor via the second support member 503c and the second gear 503d. rotational movement in the rotational direction _{G 2.} The developer stored in the second transport path P is transported in the transport direction X by the rotational movement of the second spiral blade 503a.

  In the present embodiment, the first developer transport unit 502 and the second developer transport unit 503 are configured in the same shape. However, the first developer transport unit 502 and the second developer transport unit 503 do not have to have the same shape. For example, one of the first developer transport unit 502 and the second developer transport unit 503 is used. May have an auger screw shape.

  Hereinafter, the first developer conveyance unit 502 will be described in detail. Note that the second developer conveyance unit 503 has the same configuration as the first developer conveyance unit 502, and thus description thereof is omitted. As described above, the first developer conveyance unit 502 includes the first spiral blade 502a, the first deflection preventing beam 502b, the first support member 502c, and the first gear 502d.

  The first spiral blade 502a, the first deflection preventing beam 502b, the first support member 502c, and the first gear 502d are made of, for example, a material such as polyethylene, polypropylene, high impact polystyrene, or ABS resin. When the materials of the first spiral blade 502a, the first deflection preventing beam 502b, the first support member 502c, and the first gear 502d are the same, it is preferable that the first developer transport unit 502 is integrally formed.

FIG. 16 is a cross-sectional view of the first spiral blade 502a and the first deflection preventing beam 502b having a cut surface line KK in FIG. The first spiral blade 502a is a member having a shape surrounding the side surface of the imaginary cylindrical shape when viewed in the direction of the axis N ₃ of the imaginary cylinder is substantially annular. More specifically, the first spiral blade 502a is a member having a predetermined thickness having a surface formed by a locus of the line segment when the line segment is moved along the spiral.

Twice the value of the distance from the axis _{N 3} to a point on the farthest first spiral blade 502a, referred to as the outer diameter _{L 7} of the first spiral blade 502a. Further, the value of twice the distance from the axis _{N 3} to a point on the nearest first spiral blade 502a, referred to as the inner diameter _{L 8} of the first spiral blade 502a. Outer diameter _{L 7,} for example can be set as appropriate within a range of 10 mm to 30 mm, an inner diameter _{L 8,} for example can be appropriately set within a range of 0Mm～10mm. When the developing device 500 is small, the outer diameter L ₇ is set within a range of 10 mm to 20 mm, and the inner diameter L ₈ is set within a range of 0 mm to 5 mm.

The thickness _{L 9} of the first spiral blade 502a can be appropriately set within a range of 1 mm to 3 mm. When the developing device 500 is small, the thickness _{L 9} of the first spiral blade 502a is set within the range of 1 mm to 2 mm.

In the first spiral blade 502a, a set of partial distances from the axis _{N 3} is 50% or less 40% of the outer diameter _{L 7,} referred to as a peripheral portion _{T 3} of the first spiral blade 502a. Incidentally, the outer peripheral portion _{T 3} of the first spiral blade 502a becomes spiral-shaped. Broken line in FIG. 16 represents the boundary between the outer peripheral portion T ₃ and other parts. In this embodiment, the outer peripheral portion _{T 3} of the first spiral blade 502a, the recess _{W 3} are formed. Recess W ₃ being at the outer peripheral portion T ₃ of the first spiral blade 502a, are formed at a plurality of locations on a straight line parallel to the axis N _3. The recess _{W 3,} first deflection preventing beam 502b is provided.

Prevention beam 502b first deflection, a member for the first helical blade 502a is prevented from flexing in a direction perpendicular to the axis N _3. Prevention beam 502b first deflection, a columnar member provided parallel to the axis N _3, through a space surrounded by concave portion W _3, and is connected to the concave portion W _3. Since the recess _{W 3} in a plurality of locations on a line parallel to the axis _{N 3} are formed in the outer peripheral portion _{T 3} of the first spiral blade 502a, the first deflection preventing beam 502b is an outer peripheral portion of the first spiral blade 502a It will be provided in a straight line over a plurality of locations in the T _3.

  In the present embodiment, three first bending prevention beams 502b having the same shape are provided. Although the number of the first deflection preventing beams 502b may be an arbitrary number of three or more, if the number of the first deflection preventing beams 502b is too large, the total value of the surface areas of the first deflection preventing beams 502b is increased. As a result, the friction generated between the first deflection preventing beam 502b and the developer increases during the rotational movement of the first spiral blade 502a. Therefore, the number of the first bending prevention beams 502b is preferably 3 or more and 6 or less.

  The length in the longitudinal direction of the first deflection preventing beam 502b is 70% or more of the length in the longitudinal direction of the entire first spiral blade 502a, and more preferably 90% or more. Thereby, it is possible to further suppress the bending of the first spiral blade 502a.

The shape of the cross section perpendicular to the axis N ₃ of the first deflection preventing beam 502b is a sector table about the axis N _3. Sector base central angle to the axis N ₃ in the form of a vertical cross section of the first deflection preventing beam 502b is preferably 5 ° or to 45 °, further preferably 30 ° or less than 15 °. In the present embodiment, the central angle θ ₂ of the sector base is 25 °.

By the fan-shaped base cross section perpendicular shape to the axis N ₃ of the first deflection preventing beam 502b, it is possible to increase the rigidity of the first deflection preventing beam 502b, upon rotational movement of the first spiral blade 502a In addition, the friction generated between the first deflection preventing beam 502b and the developer can be reduced.

Area of the cross section perpendicular to the axis _{N 3} of the first deflection preventing beam 502b ^can be appropriately set within a range of 1 mm 2 to 20 mm ^2. When the developing device 500 is small, the area of the cross section perpendicular to the axis _{N 3} of the first deflection preventing beam 502b ^is set within the range of 1 mm 2 to 10 mm ^2.

In this embodiment, three first deflection preventing beam 502b, in a section perpendicular to the axis N _3, provided such that the distance from said axis N ₃ equal. The distance between the first deflection preventing beam 502b and the axis _{N 3} is more particularly, the distance between the centroid _{Z 3} and the axis _{N 3} of the cross-section shape of the first deflection preventing beam 502b. With this configuration, the balance when the first bending prevention beam 502b rotates together with the first spiral blade 502a is improved, and the bending of the first developer transport unit 502 can be further suppressed.

In a cross section perpendicular to the axis N _3, referred to as an angle preventing the beam 502b 2 two first flexure adjacent and the said axis N ₃ installation angle. Installation angle, more particularly, the centroid _{Z 3} line segments and other first antideflection beam 502b connecting the centroid _{Z 3} and the axis _{N 3} one of the first deflection preventing beam 502b and the axis _{N 3} Is an angle formed by a line segment connecting the two and the angle between 0 ° and 180 ° or less. In the present embodiment, since there are three first deflection preventing beams 502b, there are three installation angles. When the three installation angles in the present embodiment are σ ₄ , σ ₅ , and σ ₆ , the three installation angles σ ₄ , σ ₅ , and σ ₆ are all 120 °. Thus, in a cross section perpendicular to the axis N _3, a plurality of first bending prevention beam 502b is provided so as installation angle formed by the two first deflection preventing beam 502b adjacent to the said axis N ₃ is all equal As a result, the balance when the plurality of first bending prevention beams 502b rotate together with the first spiral blade 502a is improved, and the bending of the first developer conveying unit 502 can be further suppressed.

  The first spiral blade 502a is provided with first support members 502c at both ends in the longitudinal direction. The first support member 502c of this embodiment is a columnar member. In the longitudinal direction of the first spiral blade 502a, the length of the portion where one first support member 502c is provided is not less than 15% and not more than 40% of the length in the longitudinal direction of the entire first spiral blade 502a. Therefore, in the longitudinal direction of the first spiral blade 502a, the portion where the first support member 502c is not provided, that is, the length of the central portion in the longitudinal direction of the first spiral blade 502a is the longitudinal direction of the entire first spiral blade 502a. It is 60% or more and 85% or less of the length.

The outer diameter of the first support member 502c may be set to the same length as the inner diameter _{L 8} of the first spiral blade 502a, also, for example, it can be appropriately set within a range of 5 mm to 15 mm. The first support member 502c is by a driving section (not shown), in 60Rpm～180rpm, it rotates in the rotational direction _{G 1.}

  In the present embodiment, nothing is provided inside the first spiral blade 502a at the center in the longitudinal direction of the first spiral blade 502a. The space inside the first spiral blade 502a of this embodiment is used as a developer moving space. That is, the developer present in the space inside the first spiral blade 502a is not pushed by the first spiral blade 502a, and therefore does not proceed in the transport direction Y and tries to stay there. As a result, the developer present in the space inside the first spiral blade 502a appears to advance in the transport direction X when the developer traveling in the transport direction Y is used as a reference. In the present embodiment, the two developer flows in the first transport path Q cause the developer to be agitated by friction between the developers, thereby eliminating the unevenness of the toner in the developing tank 201. .

  In the present embodiment, only the first bending prevention beam 502b is provided at the center in the longitudinal direction of the first spiral blade 502a. When the material of the first spiral blade 502a and the material of the first deflection preventing beam 502b are the same hardness, or when the material of the first deflection preventing beam 502b is harder than the material of the first spiral blade 502a, the first In the bending prevention beam 502b, the volume of the portion corresponding to the central portion in the longitudinal direction of the first spiral blade 502a is preferably 5% or more and 15% or less of the volume of the central portion in the longitudinal direction of the first spiral blade 502a. By setting it to 5% or more, the first spiral blade 502a becomes difficult to bend, and by setting it to 15% or less, the occupied volume of the first developer transport unit 502 in the developing tank 201 can be reduced, and as a result, more The developer can be stored in the developing tank 201.

  As another embodiment of the present invention, a columnar member may be provided inside the first spiral blade 502a at the center in the longitudinal direction of the first spiral blade 502a. In this case, when the material of the columnar member, the material of the first spiral blade 502a, and the material of the first deflection preventing beam 502b have the same hardness, or the first deflection preventing beam than the material of the first spiral blade 502a. When the material of 502b and the cylindrical member is hard, the sum of the volume of the cylindrical member and the volume of the portion corresponding to the central portion in the longitudinal direction of the first spiral blade 502a in the first deflection preventing beam 502b is the first spiral blade. It is preferably 7% or more and 15% or less of the volume of the central portion in the longitudinal direction of 502a. By setting it to 7% or more, the first spiral blade 502a becomes difficult to bend, and by setting it to 15% or less, the occupied volume of the first developer transport unit 502 in the developing tank 201 can be reduced, and as a result, more The developer can be stored in the developing tank 201.

In the first developing agent transport unit 502 thus configured, first deflection preventing beam 502b, since the shape of the cross section perpendicular to the axis N ₃ is a sector table around the said axis N _3, the the first deflection preventing beam 502b, the rigidity in the direction perpendicular to the axis N ₃ is relatively high. The first bending prevention beams 502b are provided at a plurality of locations in the outer peripheral portion T3 of the first spiral blade 502a, and _three first bending prevention beams 502b are provided in the first developer conveying unit 502. It is done. Therefore, the first developer transport unit 502 is less likely to bend than the conventional developer transport unit.

  Although the conventional developer transport unit includes a spiral blade and a relatively thick rotating shaft member, the first developer transport unit 502 does not necessarily include the rotating shaft member and is provided with a rotating shaft member. Can also be made relatively thin. For example, in the conventional developer transport unit, the value of the outer diameter of the rotating shaft member / the outer diameter of the spiral blade × 100 is 20% or more and 50% or less, whereas in the present invention, the outer diameter of the rotating shaft member is / The value of spiral blade outer diameter × 100 can be 0% or more and less than 20%.

Moreover, anti-beam 502b first deflectable so provided in parallel with the axis N _3, as compared with the case of provision of non-parallel, the volume of the first deflection preventing beam 502b is small. Therefore, more developer can be stored in the developing tank 201.

  In the present embodiment, each first deflection preventing beam 502b is one continuous member. However, as a modification of the present embodiment, one first deflection preventing beam 502b is composed of a plurality of pieces. Also good.

20 toner image forming unit 30 transfer unit 40 fixing unit 50 recording medium supply unit 60 discharge unit 100 image forming apparatus 200, 200b, 200c, 200m, 200y, 400, 500 developing device 201 developing tank 202, 402, 502 first developer Conveying portions 202a, 402a, 502a First spiral blades 202b, 402b, 502b First deflection preventing beams 202c, 402c, 502c First support members 202d, 402d, 502d First gears 203, 403, 503 Second developer conveying portion 203a , 403a, 503a Second spiral blades 203b, 403b, 503b Second deflection preventing beams 203c, 403c, 503c Second support members 203d, 403d, 503d Second gear 204 Developing roller 205 Developing tank cover 206 Doctor blade 207 Partition wall 208 Toner Degree detecting sensor 250,250b, 250c, 250m, 250y toner supply pipe 300,300b, 300c, 300m, 300y toner cartridge

Claims (6)

In a developing device comprising a developing tank for storing a developer and a developing roller for carrying and supplying the developer,
The developing tank includes a spiral blade having a shape surrounding a side surface of the virtual cylinder and two or more anti-bending beams provided in parallel to the axis of the virtual cylinder, and the axis of the virtual cylinder is A developer transport unit configured to transport the developer toward the developing roller by a rotational movement around the center;
The bending prevention beam is provided over a plurality of locations in the outer peripheral portion of the spiral blade, and the shape of a cross section perpendicular to the axis of the virtual cylinder is a sector base centered on the axis. A developing device. In a developing device comprising a developing tank for storing a developer and a developing roller for carrying and supplying the developer,
The developer tank includes a spiral blade having a shape surrounding a side surface of the virtual cylinder, and three or more anti-deflection beams provided parallel to the axis of the virtual cylinder at an outer peripheral portion of the spiral blade, A developer transport unit configured to transport the developer toward the developing roller by a rotational movement about an axis of a virtual cylinder;
The developing device according to claim 1, wherein the deflection preventing beam is provided over a plurality of portions of the spiral blade.   3. The developing device according to claim 2, wherein the deflection preventing beam has a cross-sectional shape perpendicular to the axis of the virtual cylinder as a sector base having the axis as a center.   The said bending prevention beam is provided so that all the distance from this axis may become equal in the cross section perpendicular | vertical to the axis of the said virtual cylinder. Development device.   2. The bending prevention beam is provided such that, in a cross section perpendicular to the axis of the virtual cylinder, the installation angles formed by the two bending prevention beams adjacent to the axis are all equal. The developing device according to any one of -4. In an electrophotographic image forming apparatus,
An image forming apparatus comprising the developing device according to claim 1.

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