JP5309723B2 - Powder container, developing device, and image forming apparatus - Google Patents

Description

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

In a conventional electrophotographic image forming apparatus, when an electrostatic latent image is developed into a toner image, charged toner is attached to the surface of a developing roll facing the photosensitive member on which the electrostatic latent image is formed, and photosensitive In many cases, the toner is electrostatically moved from the developing roll to the photosensitive member by applying a potential difference, that is, a bias, between the body and the developing roll for development.
The toner is agitated in a developing container of a developing device and is frictionally charged. As the toner, a toner having an average particle diameter of several μm is currently used. However, in actuality, the toner particle diameter varies, and toner having a small particle diameter is also included. A toner having a small particle diameter has a large surface area per volume, and thus is easily rubbed, and a charge amount per unit volume or unit mass tends to increase. When such a highly charged toner having a small particle size, that is, an abnormally charged toner adheres to the developing roll, it adheres to the developing roll, that is, the developing sleeve surface with a stronger mirror image force than the normally charged toner.

  When the abnormally charged toner is transported to the developing area opposite to the photoreceptor, the adhesion force is stronger than that of the normally charged toner. Therefore, the abnormally charged toner is less likely to move to the photoreceptor side than the normally charged toner. There is a problem that a development failure occurs. Also, the abnormally charged toner having a small particle size has a large mirror image power and a large adhesion force to the surface of the developing roll, so that it is difficult to separate from the surface of the developing roll, and the next development is performed with the small particle size abnormally charged toner adhered. There are also problems. In this case, since the next toner adheres to the surface of the abnormally charged toner, there is a problem that a difference in charge amount, so-called unevenness occurs, the density decreases, or the previous image appears as a ghost in the next image. is there. Such a problem is disclosed in Japanese Patent Application Laid-Open No. 1-276174 as Patent Document 1, Japanese Patent Application Laid-Open No. 1-277265 as Patent Document 2, Japanese Patent Application Laid-Open No. 2-176682 as Patent Document 3, and the like. Is also described.

As a technique for dealing with such a problem, a technique described in Japanese Patent Application Laid-Open No. 8-114983 as Patent Document 4 is known.
Japanese Patent Application Laid-Open No. 8-114983 as Patent Document 4 discloses a developing sleeve after development by a roll-like or blade-like developer replacement member (9, 91 to 95) disposed opposite to the developing sleeve of the developing roll. There is described a technique for supplying a sufficiently charged toner to the surface of the developing sleeve while there is a possibility that the developer remaining on the surface is released and a part of the developer may not be released. Patent Document 4 also describes a technique for applying a voltage for electrostatically moving the developer to the developer replacement member.

JP-A-1-276174 JP-A-1-277265 JP-A-2-176682 Japanese Patent Laid-Open No. 8-114983 (“0022”, “0062” to “0064”, “0083” to “0088”, “0090” to “0097”)

  An object of the present invention is to suppress the use of a highly charged toner having a small particle diameter.

In order to solve the technical problem, the powder container of the invention according to claim 1,
A powder storage chamber for storing the frictionally charged powder;
A friction charging member that frictionally charges the powder in the powder container;
An abnormally charged powder recovery device that is disposed in the powder storage chamber and recovers abnormally charged powder having a large charge amount per unit volume, wherein the abnormally charged powder recovery roll is rotationally driven, and the frictionally charged powder An abnormally charged powder adhering member that adheres the abnormally charged powder to the surface of the abnormally charged powder collecting roll, and an abnormally charged powder collecting member that scrapes off the normally charged powder and has an electrostatic force stronger than that of the normally charged powder. A normally charged powder scraping member that comes into contact with the surface of the abnormally charged powder recovery roll with the contact pressure left on the surface;
It is provided with.

The invention according to claim 2 is the powder container according to claim 1 ,
Arranged in contact with the abnormally charged powder collecting roll and disposed on the downstream side in the rotation direction of the abnormally charged powder collecting roll with respect to the normal charged powder scraping member and adhered to the surface of the abnormally charged powder collecting roll Abnormally charged powder scraping member that scrapes and collects abnormally charged powder.
The abnormally charged powder collecting apparatus having the above is provided.

The invention according to claim 3 is the powder container according to claim 1 ,
An opposing roll that is rotationally driven and disposed opposite to the downstream side in the rotational direction of the abnormally charged powder collecting roll with respect to the normal charged powder scraping member;
An abnormally charged powder moving power source for applying an abnormally charged powder moving voltage for electrostatically moving the abnormally charged powder on the surface of the abnormally charged powder collecting roll to the opposite roll side,
An abnormally charged powder scraping member for scraping and collecting the abnormally charged powder adhering to the surface of the opposite roll;
The abnormally charged powder collecting apparatus having the above is provided.

In order to solve the technical problem, a developing device according to a fourth aspect of the invention provides:
The powder composed of toner;
A developer container containing the toner;
A developing roll that carries and rotates the toner in the developing container;
The powder container according to any one of claims 1 to 3 , wherein the toner container is a toner replenishing device that contains toner to be replenished in the developing container. The powder container according to any one of claims 1 to 3 , comprising the abnormally charged powder recovery device disposed;
It is provided with.

In order to solve the technical problem, an image forming apparatus according to claim 5 is provided.
A developing device according to claim 4 is provided.

According to the first aspect of the present invention, the normally charged powder and the abnormally charged powder having strong electrostatic force can be separated and recovered, and the abnormally charged powder having a large charge amount per unit volume is recovered. The use of highly charged toner with a small particle size can be suppressed.
According to the invention described in claim 2 , it is possible to separate and collect the normally charged powder and the abnormally charged powder having a strong electrostatic force.

According to the third aspect of the present invention, the abnormally charged powder having a large charge amount per unit volume can be collected by the opposing roll and the abnormally charged powder scraping member, compared with the case where this configuration is not provided. Thus, abnormally charged powder can be efficiently recovered.
According to the fourth aspect of the invention, the amount of abnormally charged powder that is discharged from the toner discharge port to the developing container and carried on the developing roll can be suppressed.
According to the fifth aspect of the present invention, the amount of abnormally charged powder discharged from the toner discharge port to the developing container and carried on the developing roll can be suppressed, and the use of abnormally charged powder in image formation can be suppressed. A reduced image forming apparatus can be provided.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

FIG. 1 is an overall explanatory view of an image forming apparatus according to a first embodiment.
In FIG. 1, a printer U as an example of an image forming apparatus according to a first embodiment includes a printer main body U1 as an example of an image forming apparatus main body, and an example of an detachable body that is detachably supported with respect to the printer main body U1. A process cartridge U2 and a fixing unit U3 are included.
The printer body U1 includes a controller C as an example of a control unit configured by a microcomputer as an example of a small information processing apparatus, an image processing device IPS whose operation is controlled by the controller C, and an example of a latent image formation drive circuit. A laser driving circuit DL, a power supply device E, and the like are included. The power supply device E applies a voltage to a charging roller CR, a developing roller Ga, a transfer roller Tr, and the like which will be described later.
The image processing device IPS converts print information input from an external host computer or the like into image information for forming a latent image, and outputs the image information to the laser drive circuit DL at a predetermined time, that is, at a timing. The laser drive circuit DL outputs a laser drive signal to the latent image forming apparatus according to the input image information.

  The process cartridge U2 includes a rotating image carrier PR, a charging roll CR as an example of a charger, a cleaner CL as an example of a cleaner, a developing device G, and a toner replenishing device TH as an example of a powder container. doing. The toner replenishing device TH replenishes the developing container V of the developing device G with toner as an example of replenishing powder accommodated therein. Inside the developing container V, a developing roll Ga as an example of a developing member, a supply member Gb for supplying the developer in the developing container V to the developing roll Ga, and the toner supplied from the toner supply device TH are stirred in the axial direction. An auger Gc as an example of an agitating and conveying member to be conveyed is rotatably supported.

The surface of the rotating image carrier PR is charged by the charging roll CR in the charging region Q1, and a laser beam L as an example of the latent image writing light emitted from the latent image forming apparatus ROS at the latent image writing position Q2. Thus, an electrostatic latent image is written. The electrostatic latent image is developed into a toner image by the developing roll Ga in the developing area Q3, and is transferred by the transfer roll Tr in the transfer area Q4 formed by the pressure contact area with the image carrier PR and the transfer roll Tr as an example of the transfer member. It is transferred to the recording sheet S. Residual toner on the surface of the image carrier PR is removed by a cleaning blade CB as an example of a cleaning removal member of the cleaner CL in a cleaning region Q5 as an example of a cleaning region downstream of the transfer region Q4. The toner is collected in the toner collection container CL.
A film seal FS as an example of a flexible thin film body is provided on the opposite side of the cleaning blade CB, and the toner collected in the toner collection container CL spills out from the film seal FS. To prevent.

  A recording sheet S as an example of a medium taken out from the paper feed tray TR1 at the lower part of the printer main body U1 by a pickup roll Rp as an example of a medium takeout member includes a retard roll and a paper feed as an example of a medium feed member. Media conveyance timing adjustment that is separated one by one by a separation roll Rs having a roll, conveyed by a sheet conveyance roll Ra arranged along the sheet conveyance path SH, and arranged upstream in the sheet conveyance direction of the transfer region Q4. The sheet is conveyed to the transfer region Q4 at a predetermined timing by a registration roll Rr as an example of a member.

The transfer roll Tr to which a transfer bias is applied at a predetermined timing from the power supply device E whose operation is controlled by the controller C transfers the toner image on the image carrier PR to the recording sheet S that passes through the transfer region Q4.
The recording sheet S on which the toner image is transferred in the transfer area Q4 is conveyed to the fixing unit U3 with the toner image unfixed. The fixing unit U3 includes a fixing device F including fixing rollers Fh and Fp as an example of a pair of fixing members, and a fixing region Q6 is formed by a pressure contact region of the pair of fixing rollers Fh and Fp. The recording sheet S conveyed to the fixing unit U3 is fixed with a toner image by a pair of fixing rolls Fh and Fp of the fixing device F in the fixing region Q6. The recording sheet S on which the fixing toner image is formed is guided by sheet guides SG1 and SG2 as examples of a medium guide member, and is discharged from the discharge roll R1 as an example of a discharge member to the discharge tray TRh on the upper surface of the printer body U1. The

  In FIG. 1, tray covers TC1 and TC2 as an example of an opening / closing unit are supported on the upper portion of the image forming apparatus main body U1 so as to be rotatable about rotation centers TC1a and TC2a. The discharge tray TRh is constituted by the upper surface. The tray cover TC1 moves between an open position where the upper end of the image forming apparatus U1 is opened and a closed position where the upper end is closed in order to attach and detach the process cartridge U2.

(Description of toner replenishing device TH and developing device G)
FIG. 2 is an enlarged view of the toner supply device and the developing device according to the first exemplary embodiment.
FIG. 3 is an explanatory diagram illustrating the toner conveyance direction from the toner supply device of Example 1 to the developing roll.
1, 2, and 3, the toner supply device TH includes a toner supply container TH <b> 1 as an example of a powder storage chamber that stores toner. At the lower end of the toner supply container TH1, toner supply paths TH2 that connect the toner supply container TH1 and the developing container V are formed at both ends in the front-rear direction. In the toner supply container TH1, an agitator TH3 as an example of a friction charging member and a conveying member is rotatably arranged. The agitator TH3 is composed of a wire formed in a spiral shape with different winding directions from the axial center to both ends.
Therefore, the toner stored in the toner supply container TH1 is conveyed while being stirred by the agitator TH3 to both ends in the front-rear direction of the toner supply container, and supplied to the developing container V from the toner supply path TH2.
Such toner supply path TH2 and agitator TH3 are conventionally known, and are described in, for example, Japanese Patent Application Laid-Open No. 2004-109335.

  An abnormally charged toner collecting device 1 as an example of an abnormally charged powder collecting device is disposed in the lower left part of the toner supply container TH1. The abnormally charged toner collecting device 1 has an abnormally charged toner collecting roll 3 as an example of an abnormally charged powder collecting roll that extends in the front-rear direction and rotates in the direction of an arrow 2. The abnormally charged toner collecting roll 3 of Example 1 is configured in the same manner as the developing roll Ga. That is, the abnormally charged toner collecting roll 3 has a magnet roll 3a as an example of an abnormally charged powder adhering member fixedly supported, and a sleeve 3b as an example of a powder carrier to be rotationally driven. A normally charged toner scraping blade 4 as an example of a normally charged powder scraping member protruding upward is supported on the blade support wall TH1a of the toner supply container TH1 on the lower right side of the abnormally charged toner collecting roll 3. . The normally charged toner scraping blade 4 is in contact with the right side surface of the abnormally charged toner collecting roll 3.

The normally charged toner scraping blade 4 scrapes off the normally charged toner Tna adhering to the surface of the abnormally charged toner collecting roll 3, and has a higher charge and higher image power than the normally charged toner Tna. The abnormally charged toner collecting roller 3 is in contact with the abnormally charged toner collecting roller 3 with a contact pressure that leaves the abnormally charged toner Tnb having a small particle size having a strong adhesion to the toner collecting roller 3 without being scraped off.
The normally charged toner Tna scraped off by the normally charged toner scraping blade 4 is returned to the toner supply container TH1 and conveyed from the toner supply path TH2 to the developing container V by the agitator TH3.

The scraper support wall TH1b of the toner supply container TH1 on the lower left side of the abnormally charged toner collecting roll 3 is supported by a scraper support member 6 that protrudes to the right. The scraper support member 6 has an abnormality that protrudes to the right. A scraper 7 as an example of a charged powder scraping member is supported.
The scraper 7 is in contact with the abnormally charged toner collecting roll 3 on the downstream side in the rotational direction of the normally charged toner collecting scraping blade 4 of the abnormally charged toner collecting roll 3.
Accordingly, the abnormally charged toner Tnb conveyed to the downstream side in the rotation direction of the abnormally charged toner collecting roll 3 without being scraped off by the normally charged toner scraping blade 4 is scraped off by the scraper 7 and formed below the scraper 7. The toner is collected in the abnormally charged toner collecting chamber 8.
The abnormally charged toner collecting device 1 is constituted by the abnormally charged toner collecting roll 3, the normally charged toner scraping blade 4, the scraper supporting member 6, the scraper 7, and the abnormally charged toner collecting chamber 8.

1, 2, and 3, the developing device G includes a developing container V and a developing container cover VC that covers an upper portion of the developing container V.
The developer container V includes a toner supply chamber V1 into which toner is supplied from a supply device TH, a toner transfer chamber V2 adjacent to the toner supply chamber V1, and a developing roll Ga adjacent to the toner transfer chamber V2. A developing chamber V3 to be accommodated.
In the toner supply chamber V1, the auger Gc is rotatably arranged. The auger Gc is supported at the front part of the rotating shaft Gc1, the front shaft of the rotating shaft Gc1, the front conveying blade Gc2 that is supported by the rear part of the rotating shaft Gc1, and that conveys the toner from the rear to the front. And a rear conveying blade Gc2 that conveys the toner from the rear to the rear. An auger drive gear G2 is supported at the rear end of the rotary shaft Gc1, and is driven by a drive source (not shown).
Therefore, the toner supplied from the toner supply path TH2 to both ends in the front-rear direction of the toner supply chamber V1 of the developing container V is conveyed while being agitated by the auger Gc toward the center in the front-rear direction of the toner supply chamber V1. The toner is leveled so as not to bias the front and rear ends. Therefore, the toner that is substantially uniformly distributed in the axial direction is supplied from the toner replenishing chamber V1 to the toner transport chamber V2.

  A stirring member Gb is rotatably disposed in the toner transfer chamber V2. The stirring member Gb includes an elastic conveyance member support member Gb2 that can rotate around a rotation axis Gb1, and an elastically deformable elastic conveyance member Gb3 supported by the elastic conveyance member support member Gb2. A stirring member drive gear G3 is supported at the rear end of the rotation shaft Gb1, and is driven by a drive source (not shown). When the stirring member Gb rotates, the elastic conveying member Gb3 comes into contact with the bottom surface V2a of the toner conveying chamber V2 and conveys the elastic conveying member supporting member Gb2 so as to sweep out the toner to the developing chamber V3.

FIG. 4 is an enlarged view of a main part of the developing roll portion of the developing device.
A developing roll Ga is arranged in the developing chamber V3. The developing roll Ga includes a non-rotatable magnet roll Ga1 and a developing sleeve Ga2 disposed on the outer periphery of the magnet roll Ga1 and driven to rotate. The magnet roll Ga1 has a developing magnetic pole S1 disposed so as to face the developing region Q3. A first transport magnetic pole N1 that stabilizes the magnetic force of the magnet roll Ga1 and attracts toner to the surface of the development sleeve Ga2 and transports it to the development region Q3 is formed on the upstream side of the development magnetic pole S1 in the rotation direction of the development roll Ga. ing. A pickup / trimming magnetic pole S2 as an example of an attracting magnetic pole and a layer thickness regulating magnetic pole for adsorbing the toner in the developing chamber V3 to the surface of the developing sleeve Ga2 is formed on the upstream side of the transporting magnetic pole N1 in the rotation direction of the developing roll Ga. Yes. In the pick-up / trimming magnetic pole S2, a second transport magnetic pole N2 is arranged on the upstream side in the rotation direction of the developing roll Ga. The second transport magnetic pole N2 stabilizes the magnetic force of the magnet roll Ga1 and prevents the toner transported to the developing chamber V3 from leaking into the developing area Q3 from between the developing chamber V3 and the developing roll Ga.

  A layer thickness regulating member SK supported by the developer container cover VC is in contact with the surface of the developing sleeve Ga2 near the pickup / trimming magnetic pole S2. The layer thickness regulating member SK regulates the layer thickness of the toner adhering to the surface of the developing sleeve Ga2, and frictionally charges the toner between the layer thickness regulating member SK and the developing sleeve Ga2.

A bottom wall V3a as an example of an upstream side movement preventing member of the developing chamber V3 that is inclined upward toward the left is formed below the developing roll Ga. The distance between the bottom wall V3a and the surface of the developing sleeve Ga2 is set to the upstream side movement prevention distance L1.
In other words, a toner reservoir composed of toner that is regulated by the layer thickness regulating member SK and adhered to the surface of the developing roll Ga on the upstream side of the layer thickness regulating member SK between the developing roll Ga and the bottom wall V3a. Although the Tnc is formed, the upstream side movement prevention distance L1 is set so that the lower end of the toner reservoir Tnc contacts the bottom wall V3a before the upstream end of the toner reservoir Tnc reaches the vicinity of the transport magnetic pole N2. .
Thus, a barrier is formed between the developing sleeve Ga2 and the bottom wall V3a by the toner reservoir Tnc. As a result, even when new toner is supplied by the stirring member Gb, the toner is reduced from being conveyed to the developer reservoir upstream space V3b upstream of the toner reservoir Tnc by the barrier of the toner reservoir Tnc.

(Operation of Example 1)
In the image forming apparatus U having the above-described configuration, the toner in the toner replenishing container TH1 of the toner replenishing apparatus TH is agitated and frictionally charged by the agitator TH3. A highly charged toner is included as an example of the toner. The toner Tnb having a small particle size and high charge and large image power compared to the normally charged toner Tna has a strong adhesion force to the abnormally charged toner collecting roll 3 of the abnormally charged toner collecting device 1, and therefore the normally charged toner scraping blade. 4 is not scraped off and is collected in the abnormally charged toner collecting chamber 8. The normally charged toner Tna is not collected by the abnormally charged toner collecting device 1 but is scraped off by the normally charged toner scraping blade 4 and returned to the toner replenishing container TH1, and from the toner replenishment path TH2 by the agitator TH3. It is conveyed to the developing container V of the developing device G.
Therefore, in the toner replenishing device TH according to the first exemplary embodiment, the amount of the abnormally charged toner Tnb having a small particle diameter and a high charge contained in the toner conveyed from the toner replenishing device TH to the developing device G is reduced. As a result, in the image formation, the use of the abnormally charged toner having a small particle diameter and high charge in the developing device G is suppressed.

In the developing device G of the image forming apparatus U according to the first exemplary embodiment, the toner regulated by the layer thickness regulating member SK adheres to the surface of the developing roll Ga on the upstream side of the layer thickness regulating member SK and accumulates toner Tnc. Form. The bottom wall V3a of the developing chamber V3 of the developing container V according to the first exemplary embodiment is configured so that the upstream end in the rotation direction of the developing sleeve Ga2 of the toner reservoir Tnc reaches the upstream space V3b in the vicinity of the conveying magnetic pole N2 of the magnet roll Ga1. An upstream movement prevention distance L1 that is a distance from the surface of the developing sleeve Ga2 is set so that the lower end of the toner reservoir Tnc contacts the bottom wall V3a.
For this reason, a barrier is formed between the developing sleeve Ga2 and the bottom wall V3a by the toner reservoir Tnc. Therefore, when a new toner is transferred from the toner transfer chamber V2 to the developing chamber V3, the transferred toner is transferred. Is transported to the upstream space V3b as compared with the case where there is no toner reservoir Tnc.

  Therefore, the supply of toner to the upstream space V3b and the supply of toner to the surface of the developing sleeve Ga2 in the vicinity of the transport magnetic pole N2 are reduced. As a result, the chance of supplying and adhering highly charged toner to the surface of the developing sleeve Ga2 other than the vicinity of the pickup / trimming magnetic pole S2 is reduced. Thereby, it is possible to prevent the abnormally charged toner from being excessively supplied to the surface of the developing sleeve Ga2. Therefore, the density reduction caused by the abnormally charged toner Tna and the occurrence of development defects such as ghost are reduced.

(Example 2)
FIG. 5 is an enlarged view of the powder recovery apparatus according to the second embodiment.
In the description of the second embodiment of the present invention, components corresponding to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The second embodiment is different from the first embodiment in the following points, but is configured in the same manner as the first embodiment in other points.
In FIG. 5, an abnormally charged toner collecting device 11 as an example of an abnormally charged powder collecting device is disposed in the lower left part of the toner supply container TH1 ′. At the lower end portion of the abnormally charged toner collecting device 11, toner supply paths TH2 'for connecting the lower toner supply container TH1' and the developing container V are formed at both ends in the front-rear direction.
The abnormally charged toner collecting device 11 has an abnormally charged toner collecting roll 13 as an example of an abnormally charged powder collecting roll that extends in the front-rear direction and rotates in the direction of an arrow 12. The abnormally charged toner collecting roll 13 is configured in the same manner as the developing roll Ga.

A blade support wall TH1′c of a toner supply container TH1 ′ protruding leftward is formed on the upper right side of the abnormally charged toner collecting roll 13. A toner charging blade 14 as an example of a friction charging member protruding leftward is supported on the blade support wall TH1′c. The toner charging blade 14 is configured in the same manner as the layer thickness regulating member SK, and is in contact with the upper surface of the abnormally charged toner collecting roll 13.
On the bottom wall TH1′d of the toner supply container TH1 ′ below the abnormally charged toner collecting roll 13, a normally charged toner scraping member supporting portion 16 protruding upward is formed, and the normally charged toner scraping member The support unit 16 supports a normally charged toner scraping blade 17 as an example of a normally charged powder scraping member protruding rightward. The normally charged toner scraping blade 17 is configured in the same manner as the normally charged toner scraping blade 4 of the first embodiment. Therefore, the normally charged toner scraping blade 17 scrapes off the normally charged toner Tna ′ from the abnormally charged toner collecting roll 13 and also collects it in the normally charged toner collecting chamber 18 at the lower right, and the abnormally charged toner Tnb ′ becomes It is carried on the surface of the abnormally charged toner collecting roll 13 and conveyed downstream.

A counter roll 21 extending in the front-rear direction and rotating in the direction of an arrow 19 is in contact with the abnormally charged toner collecting roll 13 on the downstream side in the rotation direction of the normally charged toner scraping blade 17.
The opposite roll 21 is electrostatically transferred from the abnormally charged toner collecting roll 13 to the opposite roll 21 by an abnormally charged toner moving power source E1 (not shown) as an example of an abnormally charged powder moving power source E1. A bias voltage Va as an example of an abnormally charged powder moving voltage to be moved is applied.

An abnormally charged toner scraping member support portion 22 that protrudes upward is located on the left side of the normal charging toner scraping member support portion 16 on the bottom wall TH1′d of the toner supply container TH1 ′ below the abnormally charged toner recovery roll 13. The abnormally charged toner scraping member supporting portion 22 supports a scraper 23 as an example of an abnormally charged powder scraping member protruding upward. The scraper 23 is in contact with the left surface of the facing roll 21.
An abnormally charged toner collecting chamber 24 is formed on the lower left side of the abnormally charged toner scraping member support portion 22 and the scraper 23.
The abnormally charged toner collecting roll 13, the toner charging blade 14, the normally charged toner scraping member supporting portion 16, the normally charged toner collecting scraping blade 17, the normally charged toner collecting chamber 18, the opposing roll 21, and the abnormally charged toner scraping off. The abnormally charged toner collecting device 11 according to the second exemplary embodiment is configured by the member support portion 22, the scraper 23, and the abnormally charged toner collecting chamber 24.

An agitator TH4 that conveys the toner in the normally charged toner collection chamber 18 is disposed at the lower right of the abnormally charged toner collection roll 13 toward the toner supply path TH2 ′ formed at both ends in the front-rear direction. ing. The agitator TH4 is configured similarly to the agitator TH3 of the first embodiment.
In addition, in the toner supply container TH1 ′ of the second embodiment, instead of the agitator TH3 of the first embodiment, a paddle-shaped stirring member that extends in the front-rear direction and is configured in the same manner as the stirring member Gb of the first embodiment. TH3 'is rotatably arranged. The agitating member TH3 ′ agitates the toner in the toner replenishing container TH1 ′ and conveys the toner to the toner charging region Q7 where the abnormally charged toner collecting roll 13 and the toner charging blade 14 are in contact with each other.

(Operation of Example 2)
The toner passing through the toner charging region Q7 between the toner charging blade 14 and the abnormally charged toner collecting roll 13 is frictionally charged. For this reason, the toner in the toner replenishing container TH1 ′ is adsorbed to the surface of the abnormally charged toner collecting roll 13 in a frictionally charged state and is conveyed.
The normally charged toner Tna ′ adsorbed on the surface of the abnormally charged toner collecting roll 13 and contained in the toner conveyed downstream in the rotation direction of the abnormally charged toner collecting roll 13 is scraped by the normal charged toner collecting scraping blade 17. Taken. The normally charged toner Tna ′ scraped off by the normally charged toner collecting scraping blade 17 is conveyed from the central portion in the front-rear direction to both ends by the agitator TH4, and the developing container body V is developed from the toner supply path TH2 ′. It is conveyed to the medicine container V1.

  The abnormally charged toner Tnb ′ remaining on the surface of the abnormally charged toner collecting roll 13 without being scraped off by the normally charged toner scraping blade 17 is conveyed to the downstream side in the rotation direction of the abnormally charged toner collecting roll 13 and is collected. It moves electrostatically to the surface of the facing roll 21 in the facing area between the roll 13 and the facing roll 21. The abnormally charged toner Tnb ′ adsorbed on the surface of the opposite roll 21 is scraped off by the scraper 23 on the downstream side in the rotation direction of the opposite roll 21 and is collected in the abnormally charged toner collection chamber 24.

  Therefore, in the toner replenishing device TH of the second embodiment, the abnormally charged toner Tnb ′ is separated from the normally charged toner Tna ′ side by the abnormally charged toner recovery device 11 and efficiently recovered, and the abnormally charged toner Tnb ′ is recovered. The collected toner is conveyed to the toner supply path TH2 ′. Therefore, the amount of abnormally charged toner Tnb ′ conveyed to the developing container V is reduced as compared with the first embodiment.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Modification examples (H01) to (H09) of the present invention are exemplified below.
(H01) The present invention is not limited to a printer, and can be applied to an image forming apparatus such as a copying machine, a FAX, or a multifunction machine. Further, the present invention is not limited to a monochrome image forming apparatus, and can be applied to a color image forming apparatus.

(H02) In the above embodiment, the process unit in which the toner replenishing device TH and the developing device G can be integrally replaced is illustrated, but the present invention is not limited thereto, and the toner cartridge and the developing device are configured as separate units. It is also applicable to the case.
(H03) In the second embodiment, the toner supply path TH2 'is formed at both ends in the front-rear direction, and the toner supply device that transports the toner in the toner supply container TH1 to both ends in the front-rear direction is used. The developing device has a combination of an auger Gc transported inward from the section and a developing device having a paddle-shaped toner transport member Gb. However, the present invention is not limited to this, and a combination of any conventionally known toner replenishing device and developing device can be used. . For example, the toner supply path TH2 may be provided at one end portion in the front-rear direction, and the abnormally charged toner collection device 11 may be provided only at one end portion in the front-rear direction corresponding to the toner supply path TH2. At this time, the developing device may be a developing device having a pair of agitating and conveying members, that is, so-called augers, that convey the toner replenished from the toner replenishment path TH2 formed at one end. Such a configuration is described in, for example, Japanese Patent Application Laid-Open No. 2004-109367.

(H04) In the above-described embodiment, it is desirable to arrange the abnormally charged toner collecting device in the vicinity of the toner replenishment path TH2, but it is also possible to arrange it at an arbitrary position where the toner exists. In addition, when a toner replenishing device having a toner replenishing container TH1 and a reserve tank for temporarily storing toner from the toner replenishing container TH1, either or both of the toner replenishing container and the reserve tank is abnormal. It is also possible to install a charged toner recovery device. Alternatively, the abnormally charged toner collecting device may be disposed in a part of the toner conveyance path without disposing the abnormally charged toner replenishing device in the toner replenishing container or the reserve tank. Such a configuration is described in, for example, Japanese Patent Application Laid-Open No. 2004-109367.
(H05) Although it is desirable to collect the abnormally charged toner as shown in the embodiment, only the normally charged toner is supplied to the developing container V, and the abnormally charged toner is returned to the toner supply container TH1. It is also possible to configure.
(H06) In the above embodiment, the one-component magnetic developer is used. However, the present invention is not limited to this, and a two-component developer can also be used.

(H07) In the above embodiment, the abnormally charged toner collecting roll has the same configuration as the developing roll, and the developer is adhered by magnetic force. However, the abnormally charged toner collecting roll is a conductive shaft as an example of an abnormally charged powder adhering member. It is also possible to apply a voltage to the conductive axis to form an electric field, and to apply abnormally charged toner using electrostatic force.
(H08) In the above embodiment, a barrier is formed by the bottom wall of the developing chamber V3a and the developer reservoir so that abnormally charged toner is not adhered to the surface of the developing sleeve Ga2 in the developer reservoir upstream space. This configuration can be omitted.
(H09) Although the abnormally charged powder collecting roll is used in the above embodiment, any configuration such as a belt-like member can be adopted.

FIG. 1 is an overall explanatory view of an image forming apparatus according to a first embodiment. FIG. 2 is an enlarged view of the toner supply device and the developing device according to the first exemplary embodiment. FIG. 3 is an explanatory diagram illustrating the toner conveyance direction from the toner supply device of Example 1 to the developing roll. FIG. 4 is an enlarged view of a main part of the developing roll portion of the developing device. FIG. 5 is an enlarged view of the powder recovery apparatus according to the second embodiment.

Explanation of symbols

1,11 ... Abnormally charged powder recovery device,
3 ... abnormally charged powder recovery roll,
3a: Abnormally charged powder adhering member,
4 ... Normally charged powder scraping member,
7: Abnormally charged powder scraping member,
17 ... Normally charged powder scraping member,
21 ... Opposite roll,
23. Abnormally charged powder scraping member,
E1 ... Power supply for moving abnormally charged powder,
G: Developing device,
Ga ... developing roll,
Ga1 ... abnormally charged powder adhering member,
TH ... powder container,
TH1 ... powder storage chamber,
TH3, 14 ... friction charging member,
Tna, Tna '... normal charged powder,
Tnb, Tnb '... abnormally charged powder,
U: Image forming apparatus,
V: Developer container,
Va: Abnormally charged powder moving voltage.

Claims (5)

A powder storage chamber for storing the frictionally charged powder;
A friction charging member that frictionally charges the powder in the powder container;
An abnormally charged powder recovery device that is disposed in the powder storage chamber and recovers abnormally charged powder having a large charge amount per unit volume, wherein the abnormally charged powder recovery roll is rotationally driven, and the frictionally charged powder An abnormally charged powder adhering member that adheres the abnormally charged powder to the surface of the abnormally charged powder collecting roll, and an abnormally charged powder collecting member that scrapes off the normally charged powder and has an electrostatic force stronger than that of the normally charged powder. A normally charged powder scraping member that comes into contact with the surface of the abnormally charged powder recovery roll with the contact pressure left on the surface;
A powder container comprising: Arranged in contact with the abnormally charged powder collecting roll and disposed on the downstream side in the rotation direction of the abnormally charged powder collecting roll with respect to the normal charged powder scraping member and adhered to the surface of the abnormally charged powder collecting roll Abnormally charged powder scraping member that scrapes and collects abnormally charged powder.
The powder container according to claim 1 , further comprising the abnormally charged powder recovery device having the following. An opposing roll that is rotationally driven and disposed opposite to the downstream side in the rotational direction of the abnormally charged powder collecting roll with respect to the normal charged powder scraping member;
An abnormally charged powder moving power source for applying an abnormally charged powder moving voltage for electrostatically moving the abnormally charged powder on the surface of the abnormally charged powder collecting roll to the opposite roll side,
An abnormally charged powder scraping member for scraping and collecting the abnormally charged powder adhering to the surface of the opposite roll;
The powder container according to claim 1 , further comprising the abnormally charged powder recovery device having the following. The powder composed of toner;
A developer container containing the toner;
A developing roll that carries and rotates the toner in the developing container;
The powder container according to any one of claims 1 to 3 , wherein the toner container is a toner replenishing device that contains toner to be replenished in the developing container. The powder container according to any one of claims 1 to 3 , comprising the abnormally charged powder recovery device disposed;
A developing device comprising: An image forming apparatus comprising the developing device according to claim 4 .

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