JP6028334B2 - Screening device for developing device, developing unit, image forming apparatus, and developing method - Google Patents

Description

  The present invention relates to an invention for sieving coarse particles from powder using a filter.

  2. Description of the Related Art Conventionally, an image forming apparatus that develops an electrostatic latent image using toner and forms an image is known. For example, in an electrophotographic image forming apparatus, an electrostatic latent image based on image information is formed on a photoreceptor, the electrostatic latent image is developed into a toner image with a developer containing toner, and the developed toner image is converted into a toner image. An image is formed by transferring and fixing to a sheet.

  In recent years, a toner having a small particle diameter is used as a toner used in an image forming apparatus for the purpose of improving image quality. This toner may contain coarse particles for manufacturing reasons or by being stored in a hot and humid environment and slowly aggregating. When development is performed using toner containing coarse particles, a toner image based on image data cannot be obtained accurately.

  Therefore, a sieving device is used for sieving coarse particles contained in the toner. As a sieving device for sieving coarse particles from toner, an ultrasonic sieve is known (see Patent Document 1). The ultrasonic sieve screens coarse particles contained in the toner by vibrating the filter with ultrasonic waves. However, when sieving is performed using an ultrasonic sieve, the toner softens due to frictional heat caused by the vibration of the filter, causing clogging of the filter, and the opening of the filter expands due to the stress caused by vibration. was there.

  Therefore, as a sieving device for sieving coarse particles from powder without vibrating the filter, a rotating shaft arranged in a predetermined direction, a cylindrical sheave arranged coaxially with the rotating shaft, and attached to the rotating shaft There is known one having a rotating blade (see Patent Document 2). This device has a mechanism that feeds powder supplied from upstream to the outer region from the inner region of the cylindrical sheave by rotating the rotating blades, thereby sieving the powder without vibrating the sheave. be able to.

  However, since the sieve device having a cylindrical sheave has a mechanism for feeding powder from the inner region to the outer region of the cylindrical sheave, a large space is required to collect the powder that has passed through the sheave. When a sieve device having a cylindrical sieve is mounted on an image forming apparatus in order to sieve coarse particles from toner supplied to the developing device, there arises a problem that the apparatus becomes large.

The invention according to claim 1 is a cylindrical body, a filter provided at the bottom of the cylindrical body, and a rotation axis that intersects with the filter, and rotates in the vicinity of the filter, and enters the cylindrical body. A sieve main body having a blade for stirring the supplied toner, a control unit for controlling the peripheral speed of the blade to 3 m / s or more, and a developing device for developing an electrostatic latent image, and based on rotation of the blade Introduction means for introducing the toner that has passed through the filter into the developing device, and the thickness of the blade is smaller than the length of the blade in the rotation direction when rotating about the rotation shaft Is a sieving device for a developing device.

  The developing device sieving device of the present invention includes a blade that rotates in the vicinity of the filter about a rotation axis that intersects the filter. Since the moving direction of the toner passing through the filter is narrowed in the direction of the rotation axis of the blade, it is not necessary to secure a large space in order to collect the toner passing through the filter. The developing device sieving apparatus of the present invention has the effect of suppressing the increase in size of the apparatus when mounted on the image forming apparatus by using the blade.

1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view showing a toner cartridge and a developing unit. It is a front view of a sub hopper. It is sectional drawing which shows the FF cross section of the sub hopper of FIG. It is sectional drawing which shows the GG cross section of the sub hopper of FIG. It is a perspective view which shows a sieve apparatus. It is a top view of the sieve apparatus of FIG. It is sectional drawing which shows the AA cross section of the sieve apparatus of FIG. It is sectional drawing which shows the BB cross section of the sieve apparatus of FIG. It is sectional drawing which showed the specific example of the cross-sectional shape of CC cross section of the blade in the sieve apparatus of FIG. It is sectional drawing which showed the specific example of the cross-sectional shape of DD cross section of the braid | blade in the sieve apparatus of FIG. It is a front view of the rotary body which has three blades. It is a top view of the rotary body of FIG. It is a front view of the rotary body which has four blades. It is a top view of the rotary body of FIG. It is a cross-sectional view showing a developing device. It is a longitudinal cross-sectional view which shows a developing device. It is a hardware block diagram of a control part. It is a functional block diagram of a control part. FIG. 6 is a process flow diagram showing processing of the image forming apparatus. It is the schematic which shows the state which supplied the toner to the sieve apparatus of FIG. FIG. 7 is a schematic view showing a state where toner is being screened by the sieving device of FIG. 6. FIG. 7 is a schematic view showing a state where toner is being screened by the sieving device of FIG. 6. FIG. 6 is a process flow diagram showing processing of the image forming apparatus. It is sectional drawing which shows the sieve apparatus which concerns on one Embodiment of this invention.

[First Embodiment]
<< Overall Configuration of Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. First, the overall configuration of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram showing an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 forms an image by fixing toner on a sheet as an example of a recording medium.

  As shown in FIG. 1, the image forming apparatus 1 includes a paper feeding unit 210, a conveyance unit 220, an image forming unit 230, a transfer unit 240, a fixing unit 250, a control unit 500, and an operation panel. 510.

  As shown in FIG. 1, the paper feeding unit 210 includes a paper feeding cassette 211 on which papers to be fed are stacked, and a paper feeding roller 212 that feeds the papers stacked on the paper feeding cassette 211 one by one. It has.

  The transport unit 220 waits between a roller 221 that transports the paper fed by the paper feed roller 212 in the direction of the transfer unit 240 and the leading end of the paper transported by the roller 221, and the paper is loaded at a predetermined timing. A pair of timing rollers 222 that are sent to the transfer unit 240 and a paper discharge roller 223 that discharges the paper on which the toner is fixed by the fixing unit 250 to the paper discharge tray 224 are provided.

  The image forming unit 230 includes an image forming unit Y that forms an image using a developer having yellow toner (toner Y) in order from the left to the right in FIG. An image forming unit C using a developer having cyan toner (toner C), an image forming unit M using a developer having magenta toner (toner M), and a black toner (toner K). The image forming unit K using the developed developer and an exposure device 233 are provided. In the present embodiment, an “image forming unit” is used to indicate an arbitrary image forming unit among the image forming units (Y, C, M, K).

  In FIG. 1, the four image forming units have substantially the same mechanical configuration except that the developers used are different. Each image forming unit is provided so as to be rotatable in the clockwise direction in FIG. , 231K) each charging device (232Y, 232C, 232M, 232K) for uniformly charging the surface, and each toner cartridge (234Y, 234C, 234M, 234K) for supplying each color toner (Y, C, M, K). 234K) and a latent image latent image formed on the surface of the photosensitive drum (231Y, 231C, 231M, 231K) by the exposure unit 233 using the toner supplied from the toner cartridge (234Y, 234C, 234M, 234K). Each developing unit (10Y, 10C, 10M, 10K) that develops an image and a toner image on a transfer medium Each surface of the photosensitive drum (231Y, 231C, 231M, 231K) after the next transfer is neutralized by each static eliminator (235Y, 235C, 235M, 235K) and the static eliminator (235Y, 235C, 235M, 235K). And cleaning devices (236Y, 236C, 236M, 236K) for removing transfer residual toner remaining on the surfaces of the photosensitive drums (231Y, 231C, 231M, 231K).

  In the present embodiment, “photosensitive drum 231” is used when any photosensitive drum among the photosensitive drums (231Y, 231C, 231M, 231K) is shown. The “charger 232” is used to indicate an arbitrary charger among the chargers (232Y, 232C, 232M, 232K). “Toner cartridge 234” is used to indicate an arbitrary toner cartridge among the toner cartridges (234Y, 234C, 234M, 234K). Further, “development unit 10” is used to indicate an arbitrary development unit among the development units (10Y, 10C, 10M, 10K). Further, in the case of indicating any static eliminator among the static eliminators (235Y, 235C, 235M, 235K), the “static eliminator 235” is used. Further, in the case where any cleaning device among the cleaning devices (236Y, 236C, 236M, 236K) is indicated, the “cleaning device 236” is used.

  The exposure unit 233 reflects the laser light L emitted from the light source 233a based on the image information by the polygon mirrors (233bY, 233bC, 233bM, 233bK) that are rotationally driven by a motor, and the photosensitive drums (231Y, 231C, 231M). , 231K). As a result, an electrostatic latent image based on the image information is formed on the photosensitive drum 231.

  The transfer unit 240 includes a drive roller 241 and a driven roller 242, an intermediate transfer belt 243 as a transfer medium that is stretched around these rollers and can rotate counterclockwise in FIG. 1 as the drive roller 241 is driven, and an intermediate transfer belt A primary transfer roller (244Y, 244C, 244M, 244K) provided opposite to the photosensitive drum 231 with the belt 243 interposed therebetween, and a secondary opposing roller with the intermediate transfer belt 243 interposed at the transfer position of the toner image onto the paper. And a secondary transfer roller 246 provided to face the H.245. It should be noted that the “primary transfer roller 244” is used when an arbitrary primary transfer roller is shown among the primary transfer rollers (244Y, 244C, 244M, 244K).

  In the transfer unit 240, each toner image formed on the surface of the photosensitive drum 231 is transferred (primary transfer) onto the intermediate transfer belt 243 by applying a primary transfer bias to the primary transfer roller 244. In addition, since the secondary transfer bias is applied to the secondary transfer roller 246, the toner image on the intermediate transfer belt 243 is transferred to the sheet being conveyed that is sandwiched between the secondary transfer roller 246 and the secondary opposing roller 245. (Secondary transfer).

  The fixing unit 250 is provided with a heater inside, and a heating roller 251 that heats the paper to a temperature higher than the fixing lower limit temperature of the toner, and a contact surface (nip portion) by pressing the heating roller 251 so as to be rotatable. ) To form a pressure roller 252. In the present exemplary embodiment, the fixing lower limit temperature means a lower limit temperature at which the toner is fixed.

  The control unit 500 includes a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM), and controls the overall operation of the image forming apparatus 1. The operation panel 510 is a display device that serves as both a display panel that displays the operation status of the image forming apparatus 1 and an operation panel that receives an operation input from the user.

<< Configuration of development unit >>
Next, the developing unit 10 will be described in detail. First, the overall configuration of the developing unit 10 will be described with reference to FIG. FIG. 2 is a perspective view showing the toner cartridge and the developing unit.

  The developing unit 10 includes a sub hopper 160 as an example of a supply device that supplies toner, a sieving device 100, and a developing device 180. The sub hopper 160 supplies the toner supplied from the toner cartridge 234 to the screen body of the screen device 100. The sieving device 100 sifts coarse particles from the toner supplied from the sub hopper 160. The developing device 180 develops the electrostatic latent image formed on the photoreceptor 231 using the toner that has passed through the sieving device 100.

  Next, a toner supply path from the toner cartridge 234 to the developing unit 10 will be briefly described. As shown in FIG. 2, the toner contained in the toner cartridge 234 is sucked by the suction pump 234c and supplied to the sub hopper 160 of the developing unit 10 by the supply pipe 234d.

<Sub hopper>
Subsequently, the sub hopper 160 will be described with reference to FIGS. 3 to 5. FIG. 3 is a front view of the sub hopper. 4 is a cross-sectional view showing the FF cross section of the sub hopper of FIG. 3. FIG. 5 is a cross-sectional view showing a GG cross section of the sub hopper of FIG. 3. The sub hopper 160 includes a bottom plate 161a in which a supply port A4 for supplying toner to the sieving device 100 is formed, a sub hopper frame 161b as a cylindrical body standing around the bottom plate 161a, and a sub hopper frame 161b. A sub hopper main body 161 having a top plate 161c provided in the upper opening and having an inlet A1 for introducing toner supplied from the toner cartridge 234, and the toner introduced from the inlet A1 are conveyed to the supply port A4. And a first upper screw 163, a second upper screw 164, and a lower screw 167 as conveying means for supplying to the sieve device 100. In the present embodiment, “standing” means providing in a standing state, for example, a state in which the sub hopper frame 161b is provided at an angle larger than 0 degrees and smaller than 180 degrees with respect to the bottom plate 161a. means. The first upper screw 163, the second upper screw 164, and the lower screw 167 are supported and bridged by the opposing surfaces of the sub hopper frame 161b. The first upper screw 163, the second upper screw 164, and the lower screw 167 are connected by gears (163a, 164a, 167a), respectively, and rotate in conjunction with driving of a motor as driving means.

  Inside the sub hopper 160, an upper chamber 162 and a lower chamber 166 are provided as storage means for storing toner by being divided vertically by an upper and lower partition plate 161d. An introduction port A1 is formed in the top plate 161c close to the upper portion of the support portion A5 of the first upper screw 163. The toner introduced into the introduction port A1 is conveyed in the direction of arrow s1 in FIG. 4 by the rotation of the first upper screw 163 and the second upper screw 164. The conveyed toner passes through the communication holes (A2, A3) and falls into the lower chamber 166.

  The toner that has passed through the communication hole A3 and dropped from the upper chamber 162 is conveyed in the direction of the arrow s2 in FIG. The conveyed toner falls from the supply port A4 and is supplied to the sieving device 100.

<Sieving device>
Subsequently, the sieving device 100 will be described with reference to FIGS. 6 to 15. FIG. 6 is a perspective view showing the sieving device. FIG. 7 is a plan view of the sieving device of FIG. 8 is a cross-sectional view showing an AA cross section of the sieving apparatus of FIG. FIG. 9 is a cross-sectional view showing a BB cross section of the sieving device of FIG. 8. FIG. 10 is a cross-sectional view showing a specific example of the cross-sectional shape of the blade in the C-C cross section in the sieving apparatus of FIG. 11 is a cross-sectional view showing a specific example of a cross-sectional shape of a DD cross section of the blade in the sieving apparatus of FIG. 9. FIG. 12 is a front view of a rotating body having three blades. 13 is a plan view of the rotating body of FIG. FIG. 14 is a front view of a rotating body having four blades. FIG. 15 is a plan view of the rotating body of FIG. The sieving device 100 includes a sieving body 120 and a replenishing unit 150, and further includes other means and members appropriately selected as necessary.

(Sieving body)
The sieve body 120 includes a frame 121 as an example of a cylindrical body, a filter 122 provided at the bottom of the frame 121, a rotating body 130, and a drive unit 140. Accordingly, the sieve body 120 functions as a powder container that stores the toner supplied in the frame 121. Further, the sieve body 120 has a function of sieving coarse particles from the toner supplied into the frame 121. Usually, the sieve body 120 is preferably used in an upright state, but may be installed at an angle.

-Frame-
Examples of the shape of the frame 121 include a cylindrical shape, a truncated cone shape, a rectangular tube shape, a truncated pyramid shape, and a hopper shape. The size of the frame 121 is appropriately selected in consideration of the toner replenishment speed to the developing device 180 and the installation space of the developing unit 10. For example, the inner diameter is 10 mm or more and 300 mm or less, preferably 16 mm or more and 135 mm or less. can do. Examples of the material of the frame 121 include metals such as stainless steel, aluminum, and iron, and resins such as ABS, FRP, polyester resin, and polypropylene resin. The structure of the frame 121 may be formed of a single member, or may be formed of two or more members.

  A supply unit 121 a connected to the supply port A <b> 4 of the sub hopper 160 is provided on at least a part of the side surface, the end surface, or the upper surface of the frame 121. The size, shape, structure, and the like of the supply unit 121a are not particularly limited as long as toner can be supplied into the sieve body 120, and are appropriately selected according to the size, shape, structure, and the like of the sieve body 120.

  The frame 121 is provided with a cleaning door 121c that opens and closes an opening for collecting the toner contained in the sieve body 120. The cleaning door 121c is attached to the sieve body 120 by a hinge so as to be opened and closed. When the operation of the sieving apparatus 100 is stopped, the filter 122 can be cleaned by opening the cleaning door 121c and collecting coarse particles remaining on the filter 122.

-Filter-
The filter 122 is not particularly limited as long as it can screen coarse particles contained in the toner supplied to the sieve body 120, and can be appropriately selected according to the purpose. Applicable filter 122 forms include, for example, an orthogonal mesh pattern, an oblique mesh pattern, a meandering mesh pattern, a mesh pattern such as a tortoiseshell pattern, a three-dimensional configuration such as a nonwoven fabric, or a porous structure. Examples include materials and forms in which coarse particles cannot substantially pass, such as hollow fibers. Among these, it is preferable to use a mesh filter 122 in terms of good sieving efficiency.

  There is no restriction | limiting in particular about the external shape of the filter 122, According to the objective, it can select suitably, For example, circular, an ellipse, a triangle, a quadrangle, a pentagon, a hexagon, an octagon etc. are mentioned. Among these, a circular shape is particularly preferable in terms of sieving efficiency. In addition, when performing the sieving operation in multiple stages, filters 122 having different openings may be installed in series.

  The opening of the filter 122 can be appropriately selected according to the particle size of the toner, but is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. If the opening of the filter 122 is too small, the processing capacity per hour tends to be lowered, and it may be difficult to efficiently obtain a toner having a desired particle diameter, and clogging tends to occur. Here, the opening of the filter 122 means the size of the opening of the filter 122 net, and the diameter is in the case of a circular opening, and the diameter of an inscribed circle in the case of a polygon. The upper limit of the opening of the filter 122 is not particularly limited, but is preferably 5 mm or less. When the opening of the filter exceeds 5 mm, it is impossible to bridge the opening with the toner when the rotation of the blade 131 is stopped, and the discharge of the screened toner may continue.

  There is no restriction | limiting in particular as a material of the filter 122, According to the objective, it can select suitably, For example, metals, such as stainless steel, aluminum, and iron, polyamide resin, such as nylon, polyester resin, polypropylene resin, acrylic resin, etc. And natural fibers such as cotton cloth. Among these, stainless steel and polyester resin are particularly preferable because they are excellent in durability even when used for a long time.

  When a resin filter is used in a conventional ultrasonic sieve, the vibration of the filter cannot be efficiently transmitted to the toner due to its elasticity. In addition, since the conventional sieve device having a cylindrical sheave has a mechanism for feeding powder from the sheave inner region to the outer region by centrifugal force, there is a problem that durability is insufficient when a resin sheave is used. occured. The sieving device 100 according to the present embodiment does not require the vibration of the filter 122 for sieving the toner by rotating the blade 131. In the sieve device 100, the toner passes through the filter 122 by its own weight. For this reason, the filter 122 made from resin is used suitably for the sieving device 100 of this embodiment. In this case, by selecting the filter 122 formed of a resin having the same polarity as the toner, adhesion of the toner to the filter 122 is suppressed.

  Further, the filter 122 to be installed is supported by a mechanism that maintains the shape of a frame or the like, and it is preferable that wrinkles and sagging are small. Wrinkles and sagging may not only cause damage to the filter 122 but also make it difficult to screen uniformly.

  The filter 122 may be configured to be detachable from the frame 121 by sliding in the radial direction of the frame 121. Thereby, since the exchange of the filter 122 becomes easy, the maintainability of the sieving device 100 is improved.

-Rotating body-
In the present embodiment, the rotating body 130 includes a blade 131 that is rotatably disposed near the filter 122 around a rotation axis Z that intersects the filter 122, and a shaft that is disposed on the rotation axis Z and to which the blade 131 is attached. 132. When the inside of the sieve main body 120 of the sieve device 100 of the present embodiment is viewed from above, the blade 131 is configured to be rotatable around the shaft 132 in the vicinity of the upper portion of the filter 122 in the direction of arrow E or the direction of the reverse arrow in FIG. Has been. As a result, the blade 131 stirs and fluidizes the toner supplied into the sieve body 120.

  In the present embodiment, the configuration of the rotator 130 is not particularly limited as long as the blade 131 can be rotated near the filter 122 around the rotation axis Z. For example, the blade 131 may be rotated using magnetic force without using the shaft 132. Further, the blade 131 may be rotated using the shaft 132 and the hub. The angle formed by the rotation axis Z and the filter 122 intersecting is not particularly limited, but is 90 degrees because the distance between the filter 122 and the blade 131 can be kept constant and contact can be prevented. It is preferable.

  In the present embodiment, that the blade 131 is close to the filter 122 means that the vortices generated by the rotation of the blade 131 are close enough to reach the filter 122. However, “proximity” does not include a state in which the blade 131 is in contact with the filter 122 in the entire rotation path. The distance between two points parallel to the rotation axis Z of the opposed surfaces of the blade 131 and the filter 122 (D1 in FIG. 3) is preferably greater than 0 mm and not greater than 5 mm, more preferably not less than 0.01 mm and not greater than 5 mm. 5 mm or more and 2 mm or less are still more preferable. Note that when the distance between two points parallel to the rotation axis Z varies depending on the position of the blade 131 on the rotation path or the measurement point, the distance (D1) is the value of all the positions on the rotation path of the blade 131. It means the distance between two points where the distance is the shortest among the measurement points. If the distance between the blade 131 and the filter 122 exceeds 5 mm, the vortex generated by the rotation of the blade 131 may not reach the surface of the filter 122 and cleaning may not be performed. In addition, the toner deposited on the filter 122 may not be sufficiently fluidized. When the distance between the blade 131 and the filter 122 is 0 mm, the toner below the blade 131 is restricted from moving upward from the state where the toner is accumulated on the filter 122. It may become impossible to fluidize.

  In the present embodiment, although not particularly limited, it is preferable that the end of the blade 131 is close to the frame 121. That the end of the blade 131 is close to the frame 121 means that the distance (D2 in FIG. 8) between the end of the blade 131 and the frame 121 is preferably 5.0 mm or less. The state is preferably 2.0 mm or less, more preferably 0.5 mm to 1.5 mm. When the distance between the end of the blade 131 and the frame 121 varies depending on the position of the blade 131 on the rotation path and the measurement point, the distance (D2) is the position on all the rotation paths of the blade 131. It means the distance between two points where the distance is the shortest among all measurement points. When the distance between the end of the blade 131 and the frame 121 exceeds 5.0 mm, the toner flows in the direction of the frame 121 due to the centrifugal force generated by the rotation of the blade 131, and the vortex only affects the periphery of the blade 131. The powder may be difficult to be discharged from the frame 121 side.

-Blade-
In the present embodiment, the sieving apparatus 100 can screen the toner without rotating the filter 122 by rotating the blade 131. As a result, transmission of vibrations of the filter 122 to the developing device 180 can be suppressed, so that the sieving device 100 can be incorporated into the developing unit 10.

  In the present embodiment, the material, structure, size, shape, and the like of the blade 131 are not particularly limited, and are appropriately selected according to the size, shape, structure, etc. of the sieve body 120. Examples of the material of the blade 131 include metals such as stainless steel, aluminum, and iron, and resins such as ABS, FRP, polyester resin, and polypropylene resin. Among these, the metal is preferable in terms of strength. Further, since the toner is handled, a resin that can contain an antistatic agent and an antistatic agent is preferable from the viewpoint of explosion prevention. The blade 131 may be formed of a single member, or may be formed of two or more members.

  The outer shape of the blade 131 is not particularly limited, and examples thereof include a flat plate shape, a rod shape, a prism shape, a pyramid shape, a columnar shape, a cone shape, and a blade shape. When the blade 131 is disposed in the sieving device 100, the length of the blade 131 in the direction parallel to the rotation axis Z (the thickness of the blade 131 indicated by Dz in FIG. 8) is thin as long as the strength can be secured. Is preferred. The thickness (Dz) of the blade 131 is determined based on the distance between two points parallel to the rotation axis Z of the facing surface of the blade 131. When the distance between two points parallel to the rotation axis Z varies depending on the measurement point, the thickness (Dz) of the blade 131 means the distance between the two points when the distance is the shortest among all the measurement points. To do. The thickness (Dz) of the blade 131 may be, for example, 0 mm to 10.0 mm, preferably 0 mm to 5.0 mm, and more preferably 0 mm to 3.0 mm. When the thickness (Dz) of the blade 131 exceeds 5.0 mm, vortices generated behind the blade 131 are reduced, and the cleaning performance on the surface of the filter 122 is deteriorated. When the thickness exceeds 10.0 mm, the energy in the rotation direction of the blade 131 given to the toner (velocity in the circumferential direction of the toner) increases, and the toner passes through the filter 122 (parallel to the rotation axis Z). Direction) may be hindered. In addition, the load on the blade driving motor 141 (motor) of the rotator 130 may increase, and more energy may be required.

  In order to maintain the strength of the blade 131, the thickness (Dz) of the blade 131 is preferably smaller than the length of the blade 131 (Dx in FIG. 2) in the rotation direction when rotating about the rotation axis Z. The length (Dx) of the blade 131 is determined based on the distance between two points in the rotational direction of the facing surface of the blade 131. When the distance between two points in the rotation direction varies depending on the measurement point, the blade length (Dx) means the distance between the two points when the distance is the shortest among all the measurement points. When the thickness (Dz) of the blade 131 is larger than the length (Dx) of the blade 131, the strength of the blade 131 may be reduced by the resistance of the toner when the blade 131 rotates. In addition, the blade 131 may give the toner too much a rotational speed, which may hinder the movement of the toner through the filter 122.

  There is no restriction | limiting in particular as a cross-sectional shape of the braid | blade 131, According to the objective, it can select suitably. In this embodiment, the cross-sectional shape of the blade 131 may be a left-right asymmetric shape such as the cross-sectional shapes A to G in FIGS. 10 and 11 or a left-right symmetrical shape such as H to J. Any of these shapes A to J can be suitably used. The shape of the CC cross section of the blade 131 and the shape of the DD cross section may be the same, for example, as in the case of the shape of C in FIG.

  The number of blades 131 arranged on the same plane is not particularly limited and is appropriately selected according to the purpose. The number of blades 131 is, for example, two (see FIGS. 6 to 9), three (see FIGS. 12 and 13), or four (see FIGS. 14 and 15). May be. The rotating body 130 shown in FIGS. 12 and 13 is an example in which each blade 131 and the shaft 132 are fixed by a hub 133. The number of blades 131 is preferably 1 to 8, more preferably 1 to 4, and particularly preferably 2. If the number of the blades 131 exceeds 8, the blades 131 may hinder the toner from dropping from the filter 122, and the maintainability also deteriorates.

  The angle of the blade 131 with respect to the filter 122 when viewed in the X-axis direction of FIG. 9 is not particularly limited and can be appropriately selected according to the purpose, but is preferably −3 to 10 degrees with respect to the filter 122. 0 degrees to 10 degrees is more preferable, and 0 degrees (horizontal) is particularly preferable. When the angle of the blade 131 with respect to the filter 122 exceeds 10 degrees, vortices generated behind the blade 131 are reduced, and the cleaning performance is deteriorated. Further, the energy in the circumferential direction given to the toner increases, and the movement of the toner toward the filter 122 may be hindered. In addition, the load on the blade driving motor 141 of the rotating body 130 may increase.

  The ratio [(X / Y) × 100]] of the area X of the locus generated by the rotation of the blade 131 and the area Y of the filter 122 is preferably 60% to 150%, more preferably 80% to 100%. . If the ratio [(X / Y) × 100]] is less than 60%, the energy associated with the rotation of the blade 131 may not be distributed over the entire surface of the filter 122. In addition, the centrifugal force generated by the rotation of the blade 131 may cause the toner to collect on the frame 121 side, and the blade 131 may not be able to give energy to the toner. If the ratio exceeds 150%, the toner may move outside the filter 122 due to the centrifugal force generated by the rotation of the blade 131, and the toner on the filter 122 may decrease and may not be sieved.

  The rotational speed (circumferential speed) of the blade 131 is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 3 m / s to 30 m / s. If the peripheral speed of the blade 131 is less than 3 m / s, the energy that the blade 131 gives to the toner is small, and the cleaning effect and the fluidization of the toner may be insufficient. If too much energy is applied, the speed of the toner in the circumferential direction increases, which may hinder the toner from dropping toward the surface of the filter 122. Further, if the toner is excessively fluidized, the mass of the toner passing through the filter 122 may be reduced.

-Shaft-
The shaft 132 is provided on the rotation axis Z in the sieve body 120, one end is attached to the drive unit 140, and the other end is attached to the blade 131. The blade 131 and the shaft 132 are rotated about the rotation axis Z by the drive of the drive unit 140. There is no restriction | limiting in particular about the magnitude | size, shape, structure, material, etc. of the shaft 132, According to the magnitude | size, shape, structure, etc. of the sieve main body 120, it can select suitably. Examples of the material of the shaft 132 include metals such as stainless steel, aluminum, and iron, and resins such as ABS, FRP, polyester resin, and polypropylene resin. The shaft 132 may be formed of a single member, or may be formed of two or more members. Examples of the shape of the shaft 132 include a rod shape and a prismatic shape.

−Driver−
In the present embodiment, the driving unit 140 includes a blade driving motor 141 and a bearing 142. The blade driving motor 141 is means for driving the rotating body 130 including the blade 131 to rotate, and examples thereof include a motor. The operation of the blade driving motor 141 is controlled by a control means such as a PLC (programmable logic controller) or a computer. The bearing 142 is a means for supporting the shaft 132 in order to rotate the rotating body 130 accurately. The bearing 142 is provided outside the frame 121 in order to avoid a failure due to toner entering. When there is a possibility that the toner may enter the driving unit 140 through the gap between the shaft 132 and the frame 121, a mechanism for preventing the toner from entering may be provided. As such a mechanism, for example, air is blown between the bearing 142 and the frame 121 and air is blown out from the gap between the shaft 132 and the frame 121 to prevent the powder from entering (air seal), or the driving unit 140. There is an air outlet for preventing the powder from entering the inside.

  The drive unit 140 may be provided with a known brake mechanism that stops the rotation of the rotating body 130 when the apparatus is stopped. By stopping the rotation of the blade 131 by the brake mechanism when the apparatus is stopped, the fluidization of the toner is immediately stopped, so that the accuracy of toner supply to the developing device 180 by the sieving apparatus 100 is improved.

  Since the sieve device 100 according to the present embodiment does not need to vibrate the filter 122 with ultrasonic waves or vibration waves, the filter 122 is clogged with powder softened or agglomerated by frictional heat or a filter caused by frictional stress. The expansion of the opening 122 can be suppressed.

(Supply Department)
In the present embodiment, the replenishing unit 150 includes a nozzle 151 and a toner sensor 152 as an example of introducing means. The nozzle 151 is an apparatus that is connected to the developing device 180 and introduces the toner that has passed through the filter 122 into the developing device 180 based on the rotation of the blade 131. The member of the nozzle 151 is not particularly limited as long as it can be replenished by introducing toner into the developing device 180. For example, a stainless steel tube may be used. The nozzle 151 has a fitting portion 151 a that is fitted into the toner supply port of the developing device 180. For example, a packing may be attached to the fitting portion 151a in order to fit the nozzle 151 to the toner supply port accurately. Further, when the filling port of the developing device 180 is small, the configuration in which the toner is directly supplied from the nozzle 151 to the developing device 180 may be replaced with a configuration in which the toner is supplied through a funnel.

  The toner sensor 152 detects the toner that has passed through the filter 122. As the toner sensor 152, a known sensor is used, and examples include a sensor that detects toner based on magnetic permeability and a sensor that detects toner using transmittance.

<Developing device>
Subsequently, the developing device 180 will be described with reference to FIGS. 16 and 17. FIG. 16 is a cross-sectional view showing the developing device. FIG. 17 is a longitudinal sectional view showing the developing device. As illustrated in FIG. 16, the developing device 180 includes a first conveying screw 182 disposed in the first accommodating portion 181, a second conveying screw 184 disposed in the second accommodating portion 183, a developing roll 185, and a doctor. Blade 186. The 1st accommodating part 181 and the 2nd accommodating part have accommodated the magnetic carrier previously.

  A replenishing port B1 connected to the nozzle 151 of the sieving device 100 is formed above the position indicated by reference numeral B1 in FIG. The first conveying screw 182 is rotationally driven by a driving means such as a motor to convey the toner replenished through the replenishing port B1 and the developer including the magnetic carrier from the left side to the right side in FIG. The conveyed developer enters the second storage portion 183 through a communication hole B2 formed in a part of the partition wall between the first storage portion 181 and the second storage portion 183. The second conveying screw 184 conveys the developer from the right side to the left side in FIG. 16 by being rotationally driven by a driving unit such as a motor.

  The developing roll 185 includes a magnet roller. Due to the magnetic force generated by the magnet roller, the developer conveyed in the second storage portion 183 is attracted to the developing roll 185. The developer adsorbed on the developing roll 185 is conveyed as the developing roll 185 rotates in the direction of the arrow in FIG. 17, and the layer thickness thereof is regulated by the doctor blade 186. The developer whose layer thickness is regulated is conveyed to a position facing the photosensitive drum 231 and adheres to the electrostatic latent image carried on the photosensitive drum 231. By this adhesion, a toner image is formed on the photosensitive drum 231. The developer that has consumed toner by development rotates as the developing roll 185 rotates, and is returned to the second storage unit 183. Further, the developer that has consumed the toner is conveyed from the right side to the left side in FIG. 16 by the second conveying screw 184 in the second accommodating portion 183, and is returned to the first accommodating portion 181 through the communication hole B3.

<Control unit>
Subsequently, the control unit 500 will be described with reference to FIGS. 18 and 19. FIG. 18 is a hardware configuration diagram of the control unit. FIG. 19 is a functional block diagram of the control unit.

  First, the hardware configuration of the control unit 500 will be described. As illustrated in FIG. 18, the control unit 500 includes a CPU 501 that controls the operation of the entire image forming apparatus 1, a ROM 502 that stores a program for operating the image forming apparatus 1, a RAM 503 that is used as a work area for the CPU 501, Non-volatile memory (NVRAM) 504 that retains data even while the image forming apparatus 1 is powered off, I / F (Interface) 506 for transmitting / receiving information to / from an external device such as a host computer, and sieve device 100 blade drive motor 141, sub hopper 160 drive means, toner sensor 152, and I / O (Input / Output) port 507 for transmitting / receiving information to / from operation panel 510.

  Next, the functional configuration of the control unit 500 will be described. As illustrated in FIG. 19, the control unit 500 includes a drive control unit 561 and a conveyance control unit 562. Each of these units is a function or means realized by any one of the constituent elements shown in FIG. 18 operating according to a command from the CPU 501 in accordance with a program stored in the ROM 502.

  The drive control unit 561 controls the rotational drive of the blade 131 by the blade drive motor 141 based on the detection result of the toner sensor 152. The conveyance control unit 562 controls the conveyance of toner by the sub hopper 160 in response to the control for starting the driving of the blade driving motor 141 by the drive control unit 561.

<Developer>
Next, the developer used in the developing device 180 will be described. There is no restriction | limiting in particular as a developer used for the image development apparatus 180, According to the objective, it selects suitably. Specific examples of the developer may be a one-component developer having toner or a two-component developer having toner and a magnetic carrier. Examples of the toner include colored toners such as yellow, cyan, magenta, and black, and clear toner.

-Toner-
There is no restriction | limiting in particular about the manufacturing method of said toner, Although it can select suitably according to the objective, What was prepared by the wet method is preferable. The wet method is a method for producing an electrostatic charge image developing toner using a dispersion medium such as water in the production process of toner base particles. Examples of the wet method include the following methods.

(A) Suspension polymerization method in which a polymerizable monomer, a polymerization initiator, a colorant and the like are suspended and dispersed in an aqueous medium and then polymerized to produce toner mother particles (b) A polymerization initiator, an emulsifier, etc. The polymer primary is obtained by adding a colorant or the like to a dispersion of polymer primary particles obtained by emulsifying the polymerizable monomer in an aqueous medium containing the polymer and polymerizing the polymerizable monomer with stirring. Emulsion polymerization aggregation method in which toner base particles are produced by agglomerating and ripening particles (c) Dispersing dispersion liquid (toner composition dispersion liquid) of polymer, colorant, etc. previously dissolved and dispersed in a solvent in an aqueous medium And a suspension process for producing toner mother particles dispersed in an aqueous medium by removing the solvent by heating or reducing the pressure.

As the component constituting the toner, any mixture selected from the following (1) to (4) is suitable.
(1) A mixture comprising at least a binder resin and a colorant (2) A mixture comprising at least a binder resin, a colorant and a charge control agent (3) From at least a binder resin, a colorant, a charge control agent and a wax (4) A mixture comprising at least a binder resin, a magnetic agent, a charge control agent, and a wax

  There is no restriction | limiting in particular as binder resin, Although it can select suitably according to the objective, A thermoplastic resin is suitable. Examples of the thermoplastic resin include a vinyl resin, a polyester resin, and a polyol resin. These may be used individually by 1 type and may use 2 or more types together. Among these, polyester resins and polyol resins are particularly preferable.

  Examples of the vinyl resin include styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, or a homopolymer of a substituted product thereof: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene. Copolymer, Styrene-vinylnaphthalene copolymer, Styrene-methyl acrylate copolymer, Styrene-ethyl acrylate copolymer, Styrene-butyl acrylate copolymer, Styrene-octyl acrylate copolymer, Styrene- Methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer Polymer, styrene-vinylethyl -Ter copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester Examples thereof include styrene copolymers such as copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, and polyvinyl acetate.

  The polyester resin is composed of a dihydric alcohol as shown in the following group A and a dibasic acid salt as shown in the group B, and further a trihydric or higher alcohol as shown in the group C. Alternatively, carboxylic acid may be added as a third component.

  Examples of Group A include ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,4-bis. (Hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene (2,2) -2,2′-bis (4-hydroxyphenyl) propane, polyoxypropylene (3, 3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -2,2 Examples include '-bis (4-hydroxyphenyl) propane.

  Examples of group B include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linolein. Examples include acids or acid anhydrides or esters of lower alcohols.

  Examples of the group C include trivalent or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid.

  Examples of the polyol resin include an alkylene oxide adduct of an epoxy resin and a dihydric phenol, or a compound having one active hydrogen in the molecule that reacts with the glycidyl ether and the epoxy group, and an active hydrogen that reacts with the epoxy resin in the molecule. And the like obtained by reacting two or more compounds.

  In addition, the following resins can be mixed and used as necessary. Examples thereof include an epoxy resin, a polyamide resin, a urethane resin, a phenol resin, a butyral resin, a rosin, a modified rosin, and a terpene resin. Typical examples of the epoxy resin include polycondensates of bisphenol such as bisphenol A and bisphenol F and epichlorohydrin.

  There is no restriction | limiting in particular as a coloring agent, Although it can select suitably according to the objective from well-known things, For example, the following are used. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the black pigment include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides. Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, etc. Can be mentioned. Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK and the like. Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B and the like. It is done. Examples of purple pigments include Fast Violet B and Methyl Violet Lake. Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC. Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake. The content of the colorant is preferably 0.1 part by mass to 50 parts by mass, and more preferably 5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  The wax is added to give the toner releasability and is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, synthetic waxes such as low molecular weight polyethylene and polypropylene; And natural waxes such as carnauba wax, rice wax, and lanolin. The content of the wax is preferably 1% by mass to 20% by mass and more preferably 3% by mass to 10% by mass with respect to 100 parts by mass of the toner.

  The charge control agent is not particularly limited and may be appropriately selected depending on the purpose. For example, nigrosine, acetylacetone metal complex, monoazo metal complex, naphthoic acid, fatty acid metal salt (metal salt of salicylic acid, metal of salicylic acid derivative) Salt), triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus alone or compounds thereof, tungsten alone Or the compound, a fluorine-type activator, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. The content of the charge control agent is preferably 0.1% by mass to 10% by mass and more preferably 0.5% by mass to 5% by mass with respect to 100 parts by mass of the toner.

  Furthermore, inorganic fine powders such as silica fine powder and titanium oxide fine powder can be externally added to the toner in order to impart fluidity.

  The number average particle diameter of the toner is preferably 3.0 μm to 10.0 μm, and more preferably 4.0 μm to 7.0 μm. Further, the ratio of the weight average particle diameter to the number average particle diameter (weight average particle diameter / number average particle diameter) of the toner is preferably 1.03 to 1.5, and more preferably 1.06 to 1.2. Here, the number average particle diameter of the toner and the ratio of the weight average particle diameter to the number average particle diameter (weight average particle diameter / number average particle diameter) are, for example, “Coulter Counter Multisizer”; manufactured by Beckman Coulter, Inc. Can be measured.

-Magnetic carrier-
The magnetic carrier is not particularly limited as long as it contains a magnetic material, and is appropriately selected according to the purpose. Specific examples of the magnetic carrier include hematite, iron powder, magnetite, and ferrite. The content of the magnetic carrier is preferably 5% by mass to 50% by mass and more preferably 10% by mass to 30% by mass with respect to 100 parts by mass of the toner.

<<< Operation and Processing of Embodiment >>>
Next, the operation and processing of the image forming apparatus 1 will be described with reference to FIGS. FIG. 20 is a processing flowchart showing processing of the image forming apparatus. FIG. 21 is a schematic view showing a state in which toner is supplied to the sieving device of FIG. 22 and 23 are schematic views showing a state where toner is being screened by the sieving device of FIG.

<< Operation and processing at the start of printing >>
When a print start request is received by the operation panel 510 or the I / F 506, the drive control unit 561 determines whether the toner sensor 152 detects toner based on a signal transmitted from the toner sensor 152 ( Step S11). If it is determined that the toner sensor 152 detects the toner (YES in step S11), the developing device 180 contains a sufficient amount of toner, so that the sieving device 100 supplies the developing device 180 to the developing device 180. Do not start toner supply.

  If it is determined that the toner sensor 152 has not detected the toner (NO in step S11), the amount of toner in the developing device 180 is insufficient, so the sieving device 100 causes the toner to be supplied to the developing device 180. Start replenishing. In this case, the drive control unit 561 outputs a signal for starting rotational driving of the blade 131 to the blade driving motor 141 (step S12). The blade driving motor 141 rotates the rotating body 130 based on the output signal. As a result, the shaft 132 rotates, and the blade 131 attached to the tip of the shaft 132 rotates close to the filter 122 about the rotation axis Z. Although it does not specifically limit as a rotational speed, It is 500 rpm-4,000 rpm. In the present embodiment, the coarse particles left on the filter 122 in the previous operation can be fluidized by rotating the blade 131 before starting the supply of toner from the sub hopper 160 to the sieving device 100. it can. As a result, the surface of the filter 122 is cleaned, so that when the toner supply is started, the sieving device 100 can efficiently execute the sieving process.

  Subsequently, the conveyance control unit 562 outputs a signal for rotationally driving the first upper screw 162, the second upper screw 163, and the lower screw 167 of the sub hopper 160 to a driving unit that drives each screw (step S13). ). As a result, each screw rotates, and the toner stored in the sub hopper 160 is conveyed and supplied to the sieving device 100.

  As shown in FIG. 21, the toner supplied from the sub hopper 160 passes through the supply part 121a and is supplied into the frame 121 of the sieve body 120 (a supply process). As a result, the toner P is accommodated in the frame 121 and is deposited on the filter 122. At this time, when the aperture of the filter and the particle size are a certain ratio or less, the powder P having a particle size smaller than the aperture of the filter also supports each other (bridge), and on the filter 122 To deposit. The blade 131 rotates the toner accumulated on the filter 122 to stir and fluidize the toner (stirring step, see FIG. 22). At this time, the blade 131 has a speed in the sieve main body 120 on which the powder P is deposited, so that a vortex V is generated backward in the traveling direction of the blade 131. Here, the vortex means a fluid flow that is alternately and randomly generated behind the solid when the solid is moved in the fluid.

  Coarse particles Pc deposited on the filter 122 are crushed in contact with the blade 131 and wound up by the vortex V generated by the rotation of the blade 131 (see FIG. 22, filter surface cleaning action). The toner Ps having a small particle diameter easily passes through the filter 122 by this cleaning action. In addition, the fluidized toner Pf shown in FIG. 23 is mixed with air by the vortex V and has a low bulk density. Thus, when the fluidized toner Pf falls due to its own weight, the small-diameter toner Ps efficiently passes through the filter 122 in a low stress state. The toner Ps that has passed through the filter 122 passes through the nozzle 151 and is introduced into the developing device 180.

  The developing device 180 develops the electrostatic latent image formed on the photosensitive drum 231 into a toner image using the toner that has passed through the filter 122 (developing process). In the transfer unit 240, a primary transfer bias is applied to the primary transfer roller 244, and each toner image formed on the surface of the photosensitive drum 231 is transferred (primary transfer) onto the intermediate transfer belt 243. Further, by applying a secondary transfer bias to the secondary transfer roller 246, the toner image on the intermediate transfer belt 243 is transferred to the sheet being conveyed that is sandwiched between the secondary transfer roller 246 and the secondary opposing roller 245 ( Secondary transfer) (transfer process). The sheet on which the toner image is transferred is heated to a temperature higher than the lower limit fixing temperature by the heating roller 251 and is pressed by the pressure roller 252. As a result, the melted toner image is fixed on the paper (fixing step).

<< Operation and processing at the end of printing >>
Next, the operation and processing of the image forming apparatus 1 at the end of printing will be described with reference to FIG. FIG. 24 is a processing flowchart showing processing of the image forming apparatus.

  When printing based on the request received by the operation panel 510 or the I / F 506 is completed, the conveyance control unit 562 stops the rotation of the first upper screw 162, the second upper screw 163, and the lower screw 167 of the sub hopper 160. Is output to the driving means for driving each screw (step S21). As a result, the rotation of each screw stops, and the supply of toner from the sub hopper 160 to the sieving device 100 stops.

  The blade 131 is rotated while the supply of toner from the sub hopper 160 to the sieving device 100 is stopped, whereby the blade 131 discharges the toner accumulated on the filter 122 and cleans the surface of the filter 122. In this case, coarse particles that have not passed through the filter 122 move to the frame 121 side by centrifugal force.

  Subsequently, the drive control unit 561 outputs a signal for stopping the rotation of the blade 131 to the blade driving motor 141 (step S22). The blade driving motor 141 stops rotating the rotating body 130 based on the output signal. As a result, the supply of toner to the developing device 180 by the sieving device 100 is stopped. In this case, since the coarse particles are moved to the frame 121 side by centrifugal force, the coarse particles can be easily recovered from the cleaning door 121c.

[Second Embodiment]
Hereinafter, the difference between the sieving apparatus according to the first embodiment and the sieving apparatus according to the first embodiment will be described with reference to FIG. FIG. 25 is a cross-sectional view showing a sieving device according to an embodiment of the present invention. In addition, in FIG. 25, about the structure which is common in the sieve apparatus which concerns on 1st Embodiment, it shows using the same code | symbol and abbreviate | omits detailed description.

  The sieving device 101 of FIG. 25 is the same as the sieving device 100 of the first embodiment except that the discharge part 121b is formed on the frame 121.

<Discharge unit>
The frame 121 is provided with a discharge portion 121b that discharges the toner exceeding the predetermined amount from the sieve main body 120 when the toner stored in the sieve main body 120 and accumulated on the filter 122 exceeds a predetermined amount. When the amount of toner supplied from the supply unit 121a is larger than the amount of toner passing through the filter 122, the amount of toner deposited on the filter 122 continues to increase. In the present embodiment, by providing the discharge unit 121b, excessive toner exceeding a predetermined amount is discharged to the outside, so that the sieving device 101 can be continuously operated for a long time, and sieving of a large amount of toner can be efficiently performed. It can be carried out.

  There are no particular restrictions on the size, shape, structure, material, and the like of the discharge unit 121b as long as excessive toner can be discharged from the screen body 120, depending on the size, shape, structure, etc. of the screen body 120. Can be selected as appropriate. Examples of the material of the discharge unit 121b include metals such as stainless steel, aluminum, and iron, and resins such as ABS, FRP, polyester resin, and polypropylene resin. There is no restriction | limiting in particular also about the shape and magnitude | size of the discharge part 121b, According to the objective, it can select suitably. The discharge unit 121b is preferably formed on any one of the side surface, the end surface, and the upper surface of the frame 121 on the toner supply side. The toner discharged from the discharge unit 121b may be replenished as it is from the supply unit 121a and sieved again.

[Supplement of Embodiment]
As mentioned above, although the sieve apparatus (100, 101) of each embodiment was demonstrated in detail, this invention is not limited to said each embodiment, A various change may be made in the range which does not deviate from the summary of this invention. For example, in each of the above-described embodiments, the one-stage blade 131 is provided on the shaft 132. However, the two-stage blade 131 may be provided at a position where the height of the shaft 132 is different as necessary.

  In each of the above embodiments, as shown in FIGS. 8 and 25, the filter 122 is provided on the entire surface of the end surface on the toner discharge side of the sieve body 120. However, the sieve device of the present invention is limited to this configuration. Not. The filter 122 may be provided on a part of the end surface of the sieve body 120 on the toner discharge side.

  In the above embodiment, the sub hopper 160 is used as a device for supplying toner to the sieving device 100. However, the present invention is not limited to the above embodiment. The above-described embodiment can be replaced with a pump such as a bellows type pump, a diaphragm type pump, a snake type pump or the like, a pressure feed using compressed air, a means such as a coil screw or an auger, or a configuration that supplies toner by using its own weight drop.

[Effect of the embodiment]
The sieving apparatus (100, 101) according to the embodiment includes a blade 131 that rotates in the vicinity of the filter 122 around a rotation axis Z that intersects the filter 122. As a result, the developing device 180 develops the toner image using the toner in which the coarse particles are sieved in advance, so that the image quality of the formed image can be prevented from being deteriorated by the coarse particles. In addition, since the blade 131 can perform the sieving process by stirring only the toner at the bottom without stirring the entire toner in the frame 121, energy consumption can be suppressed. Further, since the moving direction of the toner when the toner passes through the filter 122 based on the rotation of the blade 131 is narrowed in the rotation axis Z direction, the sieving device 100 has a large space for collecting the toner that has passed through the filter 122. Do not need. Thereby, when the sieving device 100 is mounted on the image forming apparatus 1, there is an effect that the enlargement of the image forming apparatus 1 can be suppressed. Further, the sieving apparatus 100 performs sieving without driving the filter 122 by driving the blade 131. Thereby, the sieving device 100 has an effect of suppressing the continuation of toner discharge accompanying the vibration of the filter after the operation is stopped.

  When the blade 131 of the sieving device 100 according to the above embodiment is rotated, the toner P is fluidized, and when the fluidized toner Pf falls due to its own weight, the small particle size toner Ps is efficiently filtered in a low stress state. Pass through 122. As a result, the sieving device 100 is reduced in size as compared with an ultrasonic sieving device of the same degree of efficiency, so that when the image forming device 1 is mounted, the enlargement of the image forming device 1 can be suppressed. Play.

  The nozzle 151 of the sieving device 100 according to the above embodiment has a fitting portion 151 a that is fitted into the replenishing port B <b> 1 of the developing device 180. As a result, the toner screened by the filter 122 can be immediately supplied to the developing device 180. In this embodiment, since the filter 122 is not used as a drive unit, the transmission of vibration from the sieve device 100 to the developing device 180 is suppressed, and the fitting unit 151a can be fitted to the developing device 180.

  In the sieving apparatus (100, 101) of the above embodiment, the length (Dz) of the blade 131 in the direction parallel to the rotation axis Z is the length of the blade 131 in the rotation direction when rotating around the rotation axis Z. The blade 131 is arranged to be shorter than (Dx). Accordingly, when the blade 131 is rotated, a vortex behind the blade 131 in the advancing direction is easily generated, and the toner can be efficiently fluidized.

  In the sieve device (100, 101) of the above embodiment, the distance between the blade 131 and the filter 122 can be 5 mm or less. Thereby, when the blade 131 is rotated, vortices generated in the rearward direction of the blade 131 can easily reach the filter 122, so that the toner deposited on the filter 122 can be sufficiently fluidized.

  In the sieving apparatus (100, 101) of the above embodiment, the blade 131 is attached to the shaft 132 disposed on the rotation axis Z. Thereby, there is an effect that the blade 131 can be accurately rotated around the rotation axis Z.

  In the sieve device (100, 101) of the above embodiment, the end of the blade 131 is close to the frame 121. In this case, since the blade 131 moves on the upper part of the filter 122 close to the frame 121, the vortex generated by the rotation of the blade 131 is collected even if the toner is collected on the frame 121 side by the centrifugal force due to the rotation of the blade 131. Easier to reach the powder. As a result, the toner can be efficiently screened.

  The frame 121 of the sieving device 101 of the above embodiment is provided with a discharge part 121b. As a result, excessive toner and air in the sieve body 120 can be discharged to the outside, so that the sieve device 101 can be operated continuously for a long time.

  In addition, a cleaning door 121c that can be opened and closed is formed on the frame 121 of the sieving device 100 according to the above embodiment. Thus, when the operation of the sieve device 100 is stopped, the cleaning can be performed by opening the cleaning door 121c and collecting the toner on the filter 122.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Developing unit 100 Sieve apparatus (an example of a sieving apparatus for developing apparatus)
100, 101 Sieve device 120 Sieve body 121 Frame (an example of a cylindrical body)
121a Supply unit 121b Discharge unit 121c Cleaning door (an example of a collection door)
122 Filter 130 Rotating body 131 Blade 132 Shaft 133 Hub 140 Drive unit 141 Blade drive motor 142 Bearing 150 Replenishment unit 151 Nozzle (an example of introducing means)
151a Fitting unit 152 toner sensor (an example of detection means)
160 Sub hopper (an example of a supply device)
161 Upper chamber (an example of accommodation means)
162 First upper screw (an example of supply means)
163 Second upper screw (an example of supply means)
164 Partition plate 166 Lower chamber (an example of accommodation means)
167 Lower screw (an example of supply means)
180 Developing device 181 First accommodating portion 182 First conveying screw 183 Second accommodating portion 184 Second conveying screw 185 Developing roll 186 Doctor blade 210 Paper feeding portion 211 Paper feeding cassette 212 Paper feeding roller 220 Transporting portion 221 Roller 222 Timing roller 223 Paper discharge roller 224 Paper discharge tray 230 Image forming unit 231 Photosensitive drum 231 Photoconductor 232 Charger 233 Exposure unit 234 Toner cartridge 235 Charger 236 Cleaner 240 Transfer unit (an example of transfer means)
241 Driving roller 242 Driven roller 243 Intermediate transfer belt 244 Primary transfer roller 245 Secondary counter roller 246 Secondary transfer roller 250 Fixing section (an example of fixing means)
251 Heating roller 252 Pressure roller 500 Control unit 510 Operation panel 561 Drive control unit 562 Conveyance control unit P Toner Pf Fluidized toner Ps Sifted toner V Vortex

JP 2006-23782 A JP 2009-90167 A

Claims (12)

A cylindrical body, a filter provided at the bottom of the cylindrical body, and a blade that rotates in the vicinity of the filter around a rotation axis that intersects the filter and stirs the toner supplied to the cylindrical body A sieve body having:
A control unit for controlling the peripheral speed of the blade to 3 m / s or more;
An introducing means connected to a developing device for developing an electrostatic latent image and introducing the toner that has passed through the filter based on rotation of the blade into the developing device;
Equipped with a,
The developing device sieving apparatus, wherein the blade has a thickness smaller than a length of the blade in a rotating direction when the blade rotates about the rotating shaft .   The developing device sieving apparatus according to claim 1, wherein the introduction unit includes a nozzle.   The developing device sieve according to claim 1, wherein the cylindrical body is provided with a collection door that opens and closes an opening for collecting the toner contained in the sieve body. apparatus.   The developing device sieving apparatus according to claim 1, wherein the control unit controls the peripheral speed of the blade to be 30 m / s or less.   The developing device sieving apparatus according to any one of claims 1 to 4, wherein the cylindrical body has an inner diameter of 10 mm or more and 300 mm or less.   6. The sieve for a developing device according to claim 1, wherein a distance between two points parallel to the rotation axis of the opposing surfaces of the blade and the filter is greater than 0 mm and equal to or less than 5 mm. apparatus.   The developing device sieving apparatus according to claim 1, wherein a distance between an end of the blade and the cylindrical body is 5.0 mm or less. A developing device sieving device according to any one of claims 1 to 7,
And a developing device that develops an electrostatic latent image using the toner that has passed through the filter based on rotation of the blade.   The developing unit according to claim 8, further comprising a supply device that supplies the toner to the sieving device for the developing device. A developing unit according to claim 8 or 9,
Transfer means for transferring the toner image developed by the developing unit to a recording medium;
Fixing means for fixing the toner image transferred by the transfer means to the recording medium;
An image forming apparatus comprising: A cylindrical body, a filter provided at the bottom of the cylindrical body, and a supply step of supplying toner to a sieve body having a blade;
An agitation step of agitating the toner supplied to the sieve body by rotating the blade close to the filter and rotating at a peripheral speed of 3 m / s or more around a rotation axis intersecting the filter; ,
A developing step of developing an electrostatic latent image using the toner that has passed through the filter based on rotation of the blade;
I have a,
The developing method according to claim 1, wherein a thickness of the blade is smaller than a length of the blade in a rotation direction when the blade rotates about the rotation shaft .   The developing method according to claim 11, wherein the blade is rotated in advance before the toner is supplied in the supplying step.

Images