JP2006030521A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device of a new constitution capable of imparting a prescribed amount of electrostatic charges to toner and forming a high quality image without reducing the conveyance speed of developer in spite of a simple constitution, and to provide an image forming apparatus using the developing device. <P>SOLUTION: The developing device comprises a constitution of conveying the developer by circulation by means of a first stirring member, a second stirring member and a third stirring member disposed opposite to one part of the first stirring member and a constitution of sinking the toner replenished into the opposite parts of the first and third stirring members through a toner supply port disposed above the cover of a housing into the developer through the rotation of the first and third stirring members of which the circumferential surfaces are rotated so as to move from above to below. The image forming apparatus is equipped with the developing device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device for developing an electrostatic charge latent image (hereinafter simply referred to as a latent image) formed on an image carrier as a toner image, and an image forming apparatus including the developing device.

  The surface of the image carrier is uniformly charged by a charging unit, and an exposure unit is operated based on a document or image data to form a latent image on the image carrier, and then a toner and a carrier. After the component developer is guided to the development area and the latent image is converted into a toner image by contact or non-contact development, the toner image is transferred onto a transfer material made of paper, for example, by a transfer unit, and a fixing unit 2. Description of the Related Art Image forming apparatuses that use an electrophotographic system that is fixed to the transfer material by heating and pressurizing using a toner are well known.

  In addition, a developer carrying member made of a rotatable cylindrical member, a position-fixed magnet built in the developer carrying member, and a two-component developer are agitated to give a charge amount necessary for development processing. The developing device is configured with the stirring member as a main element, and during the development processing, the stirred two-component developer adsorbed by the action of the magnet is carried on the peripheral surface of the developer carrying member, and the developer carrying member Also known is a developing device configured to sequentially convey the developer to the developing region by rotating the motor.

  In such a developing method using a two-component developer, a new amount of toner corresponding to the amount of toner consumed by image formation is appropriately replenished in the developing device, and the toner concentration in the developer is kept constant. Control to maintain the level is performed.

  Further, in the image forming apparatus as described above, there is a demand for higher image quality, and in response to such a demand, for example, the toner and carrier have a smaller particle size.

  Thus, a two-component developer mainly composed of a toner having a small particle size and a carrier having a small particle size is useful for achieving high image quality, but the fluidity of the developer itself is reduced. Therefore, it becomes difficult to sufficiently stir the developer.

  As a result, if the newly replenished toner is supplied to the development area without having a predetermined charge amount, the image quality is deteriorated due to fogging, and toner scattering is likely to occur. There's a problem.

  Such inconvenience particularly occurs when, for example, a color image having a high printing rate is continuously output.

  On the other hand, in recent years, many of the above-described image forming apparatuses have a configuration in which toner recycling means is provided to recycle and use toner from the viewpoint of environmental conservation or resource saving. In the apparatus having the constitution, the toner (recycled toner) collected from the image carrier after being subjected to development once is inferior to the unused toner in charging characteristics. There is a problem of incurring problems such as scattering.

  In order to cope with such a problem, a technique for improving the stirring efficiency of the developer has been proposed.

For example, the developer carrying member, the first agitation transport member, and the second agitation transport member are arranged in this order and in the horizontal direction with the longitudinal direction aligned, and the first agitation transport member and the second agitation transport member are arranged. The developer is configured to be able to circulate and move with a partition wall provided between the conveying member and the length of both agitating and conveying members is at least a length protruding from one end of the developer carrying member. None, and in the projected area, the direction of the agitating member on the same axis is set so that the developer is agitated and conveyed in the direction opposite to the developer conveying direction by the respective agitating and conveying members. There has been proposed a configuration in which the agent is circulated so that toner is supplied to the agitating / conveying portion having at least one agitating / conveying member in the region (see, for example, Patent Document 1).
JP 20026631 (paragraph numbers 0033 to 0044, FIG. 3)

  However, the developing device disclosed in the above-mentioned patent document develops in two portions, that is, a stirring transport unit corresponding to a region facing the developer carrier and a stirring transport unit in a protruding region in one stirring transport unit. Since the construction is such that the agent is circulated, the developing device becomes larger and the construction of the apparatus becomes complicated.

  Even if the developer agitation efficiency can be improved by the above-described configuration, the developer circulating and conveying speed in the developing device is reduced. For example, it is used for an image forming apparatus having a high process speed. It seems that there is still room for improvement as a developing device.

  In other words, when the circulating conveyance speed of the developer decreases, the toner concentration of the developer supplied to the developer carrier becomes non-uniform in the direction of the rotation axis of the developer carrier, and in particular, an image with a high printing rate is displayed. In the case of continuous output, image density unevenness tends to occur, and it becomes difficult to form a high-quality image.

  In this way, if the replenished new toner can obtain a sufficient charge amount in a short time, the developer agitation ability is increased to prevent the occurrence of fog and toner scattering, resulting in a decrease in developer conveyance ability. As a result, it is difficult to solve the two conflicting problems at the same time.

  The present invention has been made in view of the above-described problems, and the main object is to provide a predetermined charge amount to the toner without reducing the developer conveyance speed while having a simple configuration. An object of the present invention is to provide a developing device and an image forming apparatus having a novel configuration capable of forming a high-quality image.

The object of the present invention can be achieved by the following constitution.
(Claim 1)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The developer conveying capabilities of the first stirring member and the second stirring member are set to be substantially the same,
A third stirring member that does not have a developer conveying ability in the direction of the rotation axis is provided at a position opposite to the second stirring member and facing the first stirring member in the protruding region. ,
Setting the outer diameter of the third stirring member to be larger than the outer diameter of the first stirring member;
The first stirring member and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the upper side to the lower side,
The first agitating member and the third agitating member are opposed to each other, and the toner is supplied on the cover in a region corresponding to the upstream side in the developer conveying direction by the third agitating member. A toner supply port
A developing device.
(Claim 2)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The developer conveying capabilities of the first stirring member and the second stirring member are set to be substantially the same,
A third stirring member that does not have a developer conveying ability in the direction of the rotation axis is provided at a position opposite to the second stirring member and facing the first stirring member in the protruding region. ,
Setting the rotational speed of the third stirring member to be larger than the rotational speed of the first stirring member;
The first stirring member and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the upper side to the lower side,
The first agitating member and the third agitating member are opposed to each other, and the toner is supplied on the cover in a region corresponding to the upstream side in the developer conveying direction by the third agitating member. A toner supply port
A developing device.
(Claim 3)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The developer conveying capabilities of the first stirring member and the second stirring member are set to be substantially the same,
A third stirring member that does not have a developer conveying ability in the direction of the rotation axis is provided at a position opposite to the second stirring member and facing the first stirring member in the protruding region. ,
The peripheral speed of the third stirring member is set larger than the peripheral speed of the first stirring member,
The first stirring member and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the upper side to the lower side,
The first agitating member and the third agitating member are opposed to each other, and the toner is supplied on the cover in a region corresponding to the upstream side in the developer conveying direction by the third agitating member. A toner supply port
A developing device.
(Claim 4)
4. The development according to claim 1, wherein the third stirring member has a configuration in which a plurality of plate-like members are provided to be inclined in the same direction with respect to the rotation shaft. 5. apparatus.
(Claim 5)
5. The developing device according to claim 1, wherein the third stirring member has a configuration in which a plate-like rib is provided in a rotation axis direction. 6.
(Claim 6)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first agitating member is provided in the protruding region and has a developer conveying ability lower than that of the second agitating member, and a developer in a direction opposite to the developer conveying direction by the second agitating member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
A third agitating member that has substantially the same or lower developer conveying ability as the agitating portion 1A of the first agitating member and agitates while conveying the developer in a direction opposite to the conveying direction of the second agitating member; While arrange | positioning facing the stirring site | part 1A of the said 1st stirring member,
An outer diameter of the third stirring member is set larger than an outer diameter of the first stirring member;
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device.
(Claim 7)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first agitating member is provided in the protruding region and has a developer conveying ability lower than that of the second agitating member, and a developer in a direction opposite to the developer conveying direction by the second agitating member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
A third agitating member that has substantially the same or lower developer conveying ability as the agitating portion 1A of the first agitating member and agitates while conveying the developer in a direction opposite to the conveying direction of the second agitating member; While arrange | positioning facing the stirring site | part 1A of the said 1st stirring member,
The rotation speed of the third stirring member is set larger than the rotation speed of the first stirring member, and
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device.
(Claim 8)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first agitating member is provided in the protruding region and has a developer conveying ability lower than that of the second agitating member, and a developer in a direction opposite to the developer conveying direction by the second agitating member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
A third agitating member that has substantially the same or lower developer conveying ability as the agitating portion 1A of the first agitating member and agitates while conveying the developer in a direction opposite to the conveying direction of the second agitating member; While arrange | positioning facing the stirring site | part 1A of the said 1st stirring member,
The peripheral speed of the third stirring member is set larger than the peripheral speed of the first stirring member,
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device.
(Claim 9)
The third stirring member includes a stirring portion including a plurality of plate-like members provided to be inclined in the first direction with respect to the rotation axis, and a plurality of plate-like members provided to be inclined in the second direction. The developing device according to claim 6, further comprising a stirring portion.
(Claim 10)
10. The developing device according to claim 6, wherein the third stirring member has a configuration in which a plate-like rib is provided in a rotation axis direction. 11.
(Claim 11)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first stirring member is provided in the protruding region and has a developer transport capability lower than that of the second stirring member, and the developer is in the same direction as the developer transport direction by the second stirring member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
The third stirring member has a higher developer transport capability than the second stirring member and stirs while transporting the developer in the direction opposite to the transport direction of the second stirring member. While being disposed facing the part 1A,
An outer diameter of the third stirring member is set larger than an outer diameter of the first stirring member;
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device.
(Claim 12)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first stirring member is provided in the protruding region and has a developer transport capability lower than that of the second stirring member, and the developer is in the same direction as the developer transport direction by the second stirring member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
The third stirring member has a higher developer transport capability than the second stirring member and stirs while transporting the developer in the direction opposite to the transport direction of the second stirring member. While being disposed facing the part 1A,
The rotation speed of the third stirring member is set larger than the rotation speed of the first stirring member, and
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device.
(Claim 13)
A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first stirring member is provided in the protruding region and has a developer transport capability lower than that of the second stirring member, and the developer is in the same direction as the developer transport direction by the second stirring member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
The third stirring member has a higher developer transport capability than the second stirring member and stirs while transporting the developer in the direction opposite to the transport direction of the second stirring member. While being disposed facing the part 1A,
The peripheral speed of the third stirring member is set larger than the peripheral speed of the first stirring member,
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device.
(Claim 14)
The stirring portion 1A is a stirring portion composed of a plurality of plate-like members provided to be inclined in the first direction with respect to the rotation axis and a plurality of plate-like members provided to be inclined in the second direction. The developing device according to claim 11, wherein the developing device includes a region.
(Claim 15)
The developing device according to claim 11, wherein the stirring portion 1 </ b> A has a configuration in which a plate-like rib is provided in a rotation axis direction.
(Claim 16)
The developer carrying member and the first stirring member are configured such that the peripheral surfaces rotate in opposite directions when viewed at the opposing proximity point. Development device.
(Claim 17)
When the volume average particle diameter of the toner is Dt [μm] and the volume average particle diameter of the carrier is Dc [μm],
Dt = 3-5
Dc = 5 · Dt ~ 10 · Dt
The developing device according to any one of claims 1 to 16, wherein a developer containing a toner and a carrier is used.
(Claim 18)
An image forming apparatus comprising: an image carrier; an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier; and a developing unit that develops the electrostatic latent image into a toner image.
While using the developing device of any one of Claim 1 thru | or 17 as said image development means,
The moving speed of the image carrier is V [mm / sec], the maximum adhesion amount per unit area of the toner image formed on the image carrier is M [mg / cm ² ], and the direction orthogonal to the moving direction of the image carrier The maximum width of the toner image is L [mm], the developer movement amount in the rotation axis direction of the developer carrier by the second stirring member is W [g / sec], and the rotation speed of the second stirring member is R [rpm]. When
W ≧ M ・ V ・ L / 1000
R ≦ 600
An image forming apparatus.
(Claim 19)
An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, a developing unit that develops the electrostatic latent image into a toner image, and a toner on the image carrier A transfer unit that transfers the image to a transfer material or an intermediate transfer member; a cleaning unit that cleans the surface of the image carrier after the transfer; and a toner that is removed from the surface of the image carrier by cleaning is supplied to the developing unit. In an image forming apparatus having toner recycling means for recycling,
The developing device according to any one of claims 1 to 17 is used as the developing unit, and the portion on the cover of the developing device between the portion corresponding to the stirring portion 1A and the third stirring member. An image forming apparatus comprising a recycled toner supply port for supplying recycled toner at a position corresponding to the above.
(Claim 20)
The image forming apparatus according to claim 19, wherein the recycled toner supply port is located upstream of the toner supply port as viewed in the developer transport direction by the first stirring member.

  According to the developing device of the present invention, although the configuration is simple, in the transport process in the developer stirring unit, the toner in the developer is sufficiently mixed and stirred without decreasing the transport speed of the developer. Uniform dispersion can be achieved, and at the same time, a desired charge amount can be imparted to the toner, so that fog due to poor charging of the toner, occurrence of toner scattering, and the like can be suppressed as much as possible.

  In addition, the first stirring member and the third stirring member are rotated so that the respective peripheral surfaces move downward from above, and when viewed from the side, facing between the opposing portions, from above, By adopting a configuration in which the toner can be replenished, sinking of the replenished toner into the developer and uniform dispersion can be accelerated, and good charge rising characteristics of the replenished toner can be obtained.

  Further, since the axial length of the third stirring member may be shorter than the axial length of the first stirring member, for example, the developing device can be kept small for the effect to be achieved. In addition, since the container for storing the replenishing toner provided on the image forming apparatus main body side and the lower space where the toner recycling unit is installed can be used, the image forming apparatus does not need to be enlarged.

  Further, according to the image forming apparatus having the above-described configuration, the developing device as described above is provided, and the developer is sufficiently mixed and stirred by performing the developing process in a state satisfying specific operation conditions. The developer charged in a state in which the toner has a desired charge amount is supplied to the developer carrier at a uniform density in the rotation axis direction, and the latent image on the image carrier is developed with the developer. The

  Therefore, for example, when a developer in which a large amount of toner is consumed and replenished by continuous output of images with a high printing rate is used, or when the charging performance is inferior to that of unused toner, recycling is performed. Even when a developer containing toner is used, the desired charge amount can be imparted to the toner through efficient mixing and agitation, so that occurrence of toner scattering, fogging, image density unevenness, etc. can be suppressed as much as possible. A high-quality image can be stably produced.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic view showing a first embodiment of an image forming apparatus according to the present invention, FIG. 2 is a plan view showing the first embodiment of a developing apparatus according to the present invention, and FIG. AA sectional view in FIG. 2, FIG. 4 shows a BB sectional view in FIG.

  In the description, the developing device shown in FIGS. 2 to 4 will be described after the description of FIG. 1 showing the image forming apparatus composed of a digital color copying machine.

  The image forming apparatus according to the first embodiment has an automatic document feeder 1 at the top of the apparatus main body, and a belt for an image reading unit (image reading device) 2, an image forming unit 3, and a belt unit 4. Section, a sheet feeding section 5, a fixing device T, a reverse sheet discharge / refeed section 6, and an ADU 7 serving as a reverse conveying means.

  The automatic document feeder 1 is a device that feeds documents one by one, conveys them to an image reading position, and discharges the document after image reading to a predetermined location.

  The automatic document feeder 1 includes a document placing table 101 on which a document is placed, a document separating unit 103 for separating the placed document, a document transporting unit 105 for transporting the separated document, and discharging the transported document. A pair of rollers used to reverse the front and back surfaces of the original in the double-sided copy mode for reading the images on both sides of the original. The document reversing means 111 is provided.

  In view of the processing process, a plurality of documents (not shown) placed on the document placing table 101 are separated one by one by the document separating means 103, and the image reading position is passed through the document conveying section 105. It is conveyed toward.

  The document reading position is provided at a lower portion of the document conveying unit 105, where an image of the document is read through the slit 201 constituting the image reading device 2, and the read document is discharged from the document. The sheet is discharged onto the document discharge table 109 by the means 107.

  In the double-sided copy mode, the original document that has been read and transported on one side is conveyed by the document reversing means 111 in the direction indicated by the two-dot chain line arrow, and the original document is being bitten at the trailing edge in the direction of travel. The reverse rotation after the driving of the reversing unit 111 is stopped and the image is again guided to the image reading position via the document conveying unit 105, and then discharged onto the document discharge table 109 by the document discharge unit 107. Is done.

  The above process is repeated for the number of documents placed on the document placing table 101.

  The image reading device 2 includes a first mirror unit 205 and a first mirror 215 that are formed by integrating the slit 201, a lamp 213 for irradiating a document, and a first mirror 215 that reflects reflected light from the document. A second mirror unit 207 in which a second mirror 217 that reflects light and a third mirror 219 are integrated in a substantially V shape, and an image that forms an image of reflected light from the third mirror 219 on the image sensor. A lens 209 and a line-shaped image sensor (hereinafter referred to as a CCD) 211 that photoelectrically converts a light image formed by the imaging lens 209 to obtain image information are included.

  The image information is temporarily stored in a memory (not shown) after appropriate image processing.

  In a mode in which the document fed by the automatic document feeder 1 is read by the image reading device 2, the first mirror unit 205 and the second mirror unit 207 are fixed at positions as shown.

  The image signals for the respective colors read by the image reading device 2 are sequentially taken out from the memory and inputted as electric signals to the respective exposure optical systems which are electrostatic charge latent image forming means.

  The image forming unit 3 includes four image forming units (hereinafter referred to as image forming units) of yellow (Y), magenta (M), cyan (C), and black (BK) for forming a toner image corresponding to a color separation image. 30) is provided.

  Each of the image forming units 30 includes, for example, an image carrier (hereinafter referred to as a photosensitive drum) 310 in which a photosensitive layer made of a resin such as polycarbonate containing an organic photoconductor is provided on a drum-shaped metal substrate. Charger 320 of scorotron type, exposure optical system 330 as image writing means (synonymous with electrostatic charge latent image forming means), developing device 8 for developing electrostatic charge latent image, transfer means 340, photoconductor after transfer A cleaning device 350 including a blade (cleaning means) for cleaning the surface of the drum 310 is a main component.

  The developing device 8 incorporates a two-component developer containing a magnetic carrier (hereinafter simply referred to as carrier) and a non-magnetic toner (hereinafter simply referred to as toner), and is fixed in position and has a plurality of magnetic poles in the circumferential direction. And a developer carrying member (developing sleeve) having a rotatable and non-magnetic cylindrical shape incorporating a magnet in which the magnets are arranged.

  The exposure optical system 330 is an exposure unit composed of a laser optical system, and the transfer means 340 is opposed to a part of the peripheral surface of the photosensitive drum 310 via a rotating belt 401 described later. .

  Since the mechanical configuration of the four sets of image forming units described above is basically the same, reference numerals are assigned only to one set of units, and the others are omitted.

  Each of the image forming units 30 is provided with a flat surface (a stretched surface) A of a loop-shaped rotating belt (hereinafter referred to as an intermediate transfer belt) 401 that constitutes the belt unit 4 and is long in the belt installation portion. Are arranged in the order of yellow, magenta, cyan, and black from above.

  The intermediate transfer belt 401, support rollers 405, 406, 407, and a backup roller 410 that suspend the intermediate transfer belt so as to rotate are included in the belt unit 4, and the backup roller 410 includes the intermediate transfer belt. A secondary transfer unit is configured by a transfer roller 510 that is disposed so as to rotate while pressing the backup roller with 401 interposed therebetween.

  Image formation by the configuration of the image forming unit 30 and the belt unit 4 is performed as follows.

  As the image forming process starts, the surface of the photosensitive drum 310 that rotates counterclockwise is charged to a predetermined polarity by the charger 320.

  Next, the exposure optical system 330 performs exposure corresponding to the first color signal, that is, the yellow (Y) image signal, and a latent image corresponding to the (Y) image is formed on the photosensitive drum 310. Is done.

  The latent image is reversely developed by contact or non-contact development with a developer in the developing device 8 and converted into a toner image of (Y), and then transferred onto the intermediate transfer belt 401 by the action of the transfer unit 340.

  Image formation with other color signals, which is sequentially started after a predetermined time from the start of image formation with the first color signal, is performed in the same manner as described above, and each image of magenta (M), cyan (C), and black (BK). Each of the toner images is sequentially transferred so as to overlap with an image area where the toner image (Y) is formed, and a superimposed color toner image is formed on the intermediate transfer belt 401.

  On the other hand, the surface of the photosensitive drum 310 after completion of the transfer process is cleaned by the cleaning unit 350, and preparations for new image formation are made.

  Note that the start timing of each image forming process with respect to the photosensitive drum 310 or the intermediate transfer belt 401 is one side of the intermediate transfer belt 401, in the present embodiment, and the intermediate transfer belt 401. A registration sensor 413 provided in a section from a position where the transfer roller 510 is located to a position where the first set (yellow) image forming unit is provided is provided on the intermediate transfer belt 401. For example, time is measured starting from when a reference mark formed using paint is detected, and the (Y), (M), (C), and (BK) processes are sequentially started every predetermined time. It is configured.

  The detection signal from the registration sensor 413 is taken in, the time is monitored, and control related to individual processes is performed by a control unit (control means) S including a computer.

  Next, other configurations of the apparatus will be briefly described in connection with the process from when the color toner image formed on the intermediate transfer belt is transferred to the paper P and discharged to the outside of the apparatus.

  At an appropriate timing corresponding to the image formation on the intermediate transfer belt 401, the paper P is fed by the paper feed rollers 503 (513, 523) positioned in the feeding sections 501 (511, 521) of the paper feed section 5, It is conveyed toward the registration roller 551.

  Thereafter, the sheet P is fed again so as to overlap with the color toner image area on the intermediate transfer belt 401 by resuming the rotation of the registration roller 551, and the backup roller 410 and the transfer roller in the secondary transfer unit. 510, the color toner image carried (formed) on the intermediate transfer belt 401 is transferred onto the sheet P while being pressed and nipped together with the intermediate transfer belt.

  It is desirable that an appropriate transfer bias voltage is applied to the transfer roller 510 during transfer.

  The sheet P on which the toner image has been transferred is separated from the intermediate transfer belt 401 while being subjected to the action of a separation claw (not shown), and conveyed toward the fixing device T, for example.

  The fixing device T includes a fixing roller T1 having a built-in fixing heater and a pressure roller T2 that rotates while being pressed against the fixing roller. The color toner forming the image is heated and pressed by both rollers. It is melted and fixed on the paper P.

  The paper P after the fixing process by the fixing device T is completed is conveyed by a paper discharge roller 603 provided downstream thereof, and is discharged onto a paper discharge tray provided outside the apparatus main body.

  On the other hand, the surface of the intermediate transfer belt 401 after the completion of the secondary transfer is cleaned by a cleaning unit 415 including a blade, and preparations for carrying a new toner image are made.

  Note that the toner in the developer is consumed by the development process. This is because a toner concentration detection sensor is provided at an appropriate place in the developing device 8 and the toner in the developing device is based on information from the sensor. Can be provided by known techniques.

  In the figure, the solid line position of the path switching member 601 is a position held when the upper and lower surfaces of the paper P are reversed and discharged after the fixing process, and the broken line position is sent out from the fixing device as described above. This position is held when the sheet is discharged as it is.

  For example, in the reverse discharge of the paper P, the paper P sent out from the fixing device T is guided downward along the right side of the path switching member 601, and the rear end in the advancing direction is held by the roller pair 602. It is lifted by the reverse rotation of the roller pair 602 after being set in the closed state, passes through the left side of the switching member 601, reaches the paper discharge roller 603, and is discharged so as to be discharged by the paper discharge roller. Is done.

  Further, the behavior of the paper P in the double-sided copy mode using the ADU 7 is similar to that in the case of the reverse discharge. The paper P after the fixing process with the image formed on one side is moved along the right side of the switching member 601. Then, after stopping the conveyance with the rear end of the paper P in the traveling direction being sandwiched by the roller pair 605, the roller pair 605 is rotated in the reverse direction and is raised along the guide plate G, and a plurality of roller pairs The reversal of the paper P is achieved by leading to the ADU 7 having 701, 703, and 705.

  The image forming process for the second surface of the paper P is the same as described above, and any one of the above-mentioned is selected for the discharge after being sent out from the fixing device T.

  Next, the configuration of the developing device which is a toner image forming unit (developing unit) will be described in detail with reference to FIGS.

  In the present specification, the left-right direction in FIG. 2 is referred to as “front-rear direction” with reference to the developer carrier, and the up-down direction in FIG. It is called “rotational axis direction” or “longitudinal direction”, and the vertical direction in FIGS. 3 and 4 is expressed as “vertical direction”.

  The developing device 8 includes a developer carrier (developing sleeve) 800 that carries and conveys the developer, and a position closer to the developer carrier, adjacent to the longitudinal direction of the developer carrier. A first agitating member 803 that is provided (or parallel to the longitudinal direction) and agitates the developer while being conveyed in the direction of the rotation axis; and a position farther from the developer carrier, A second agitating member 805 that is provided adjacent to (in parallel with) the longitudinal direction of the one agitating member and agitates while conveying the developer in the direction of the rotation axis opposite to the developer conveying direction by the first agitating member 803; The developer carrier 800 and the first stirring member 803 are provided between the developer carrier and supply the developer to the developer carrier and store the developer removed from the developer carrier from the supply / recovery unit 815. Supply of developer to be collected in the stirring unit 816 A collecting member 809, a housing 810 for rotatably supporting a rotating member such as the developer carrier, the first stirring member, the second stirring member, and the developer supply / recovery member; A cover 812 provided on the upper portion of the housing is provided.

  In addition, the developer carrier 800 and the developer supply / recovery member 809 have substantially the same length and are configured so that both end portions have substantially the same position. The member 803 and the second stirring member 805 are configured to be longer than the length of the developer carrier 800 and the like.

  And, one end position of each of the agitating members (the downstream end when viewed in the developer conveying direction by the second agitating member, the upstream end when viewed in the developer conveying direction by the first agitating member) is By positioning in the same plane as the end portion position of the developer carrier 800, the housing 810 protrudes from the end portion of the developer carrier 800 on the other end side.

  In other words, the first agitating member 803 extends and protrudes downstream in the developer conveyance direction. Reference numeral 802 indicates a protruding region.

  In addition, the developing device 8 is in a housing corresponding to the protruding region 802 and is substantially on an extension line to which the developer supply / recovery member 809 is attached (the first stirring member 803 is sandwiched between the first stirring member 803 and the first stirring member 803). The second stirring member 805 has a third stirring member 807 provided in a rotatable manner so as to face a partial region of the first stirring member 803.

  The developer carrier 800 is a cylindrical member made of a non-magnetic metal material such as aluminum or stainless steel, and a magnet (not shown) is housed in a fixed position therein.

  As is well known, the magnet can automatically attract and hold the developer on the developer carrier and remove the developer from the developer carrier 800 using a repulsive magnetic field. It is configured to be able to.

  As described above and as shown in FIG. 3, the developer carrier 800, the developer supply / recovery member 809, and the first stirring member 803 are supplied with the developer formed in the housing 810 by the partition wall 808. The second agitation member 805 is accommodated in the developer agitation unit 816.

  The partition wall 808 provided between the first stirring member 803 and the second stirring member 805 is shorter than the first and second stirring members in a state in which both end portions in the longitudinal direction are notched. The outer regions of the end portions are passages for developer circulation (sometimes referred to as circulation passages) 820 and 821.

  The supply / recovery unit 815 and the storage agitation unit 816 store an appropriate amount of two-component developer including carrier and toner.

  Since the partition wall 808 can prevent the developer in the supply / recovery unit from being mixed with the developer in the storage and agitation unit, the developer having a predetermined charge amount is sequentially supplied to the developer carrier. This partition wall can be eliminated.

  The rotating member such as the stirring member is configured to receive power from a drive system provided on the image forming apparatus main body side and rotate in the direction of the arrow through a gear or the like. Can be used.

  In the present embodiment, the developer carrying member 800 disposed to face the already-exposed photoconductive drum 310 is counterclockwise (the photoconductive drum is opposite to the photoconductive drum in the opposite direction), and developer supply / recovery is performed. The member 809 rotates counterclockwise, the first stirring member 803 rotates counterclockwise, the second stirring member 805 rotates clockwise, and the third stirring member 807 rotates clockwise.

  The first and second agitating members are, for example, shafts (rotating shafts) J formed on the outer peripheral surface of the shaft, with a predetermined direction in the axial direction, and with a predetermined pitch p, for example, as shown in FIG. The outer peripheral surface can be configured with a spiral rib (screw) 850.

  Further, as the developer supply / recovery member 809, for example, a rotary member configured in a paddle shape by providing a plate-like blade member projecting radially outward from the circumferential surface of the rotary shaft can be suitably used.

  By defining the rotation direction of the developer carrier 800 and the developer supply / recovery member 809 as described above, the developer supplied from the developer supply / recovery member 809 to the developer carrier 800, and the developer Since the developer removed from the carrier 800 and the developer recovered by the developer supply / recovery member 809 can be reliably replaced, the toner density of the developer on the developer carrier 800 can be kept uniform. As a result, the occurrence of uneven image density can be easily suppressed.

  In the drawing, Z indicates a layer thickness regulating blade for regulating the thickness of the developer layer that is magnetically attracted and carried on the developer carrying member 800.

  Returning to FIG. 2, the thick arrows indicate the developer transport direction when the first stirring member 803, the second stirring member 805, and the third stirring member 807 rotate in the above directions, and the length of the arrows is , Developer transport capability (developer transport speed, developer transport amount, etc.).

  The first stirring member 803 has substantially the same conveying ability as a second stirring member 805 described later, and the developer is in the first direction in the rotation axis direction (in the drawing, the rotation axis direction from the upper side to the lower side). Transport to.

  The second agitating member 805 has substantially the same conveying ability as the first agitating member 803, and conveys the developer in a direction opposite to the conveying direction of the first agitating member 803, thereby circulating the developer. Make it possible.

  Further, the third stirring member 807 has, for example, a configuration in which a plurality of plate-like members are provided to be inclined in the same direction with respect to the rotation axis, and substantially has the ability to convey the developer in the rotation axis direction. Absent.

  The shape of the plate-like member can be, for example, an elliptical shape, or a configuration in which plate-like ribs are continuously extended in the rotation axis direction via the outer peripheral edge of the elliptical plate-like member. It is not limited to the shape. In addition, about the plate-shaped rib without a cut | interruption extended in a rotating shaft direction, it shows with the referential mark 858 in the figure of the rotating member mentioned later.

  The conveying capacity of the agitating member is determined by the amount of developer to be supplied to the developer carrier 800 (including the developer conveying speed in the axial direction), the smooth flow of the developer in the circulation conveying path, or It can be appropriately determined depending on required conditions such as an expected charge amount to be applied to the toner.

  The portion of the stirring member corresponding to the downstream side in the developer transport direction by the first and second stirring members 803 and 805 corresponding to the circulation passages 820 and 821 described above can be easily transferred. For example, a plate-like blade member that protrudes radially outward from the peripheral surface of the rotating shaft is provided in an appropriate range to have a paddle shape.

  According to the developing device having the above-described configuration, the developer in the storage stirring unit 816 is conveyed in the rotation axis direction indicated by the arrow while being stirred in the circumferential direction by the rotation of the second stirring member 805, and passes through the passage 820. Then, the first stirring member 803 is acted on.

  While being stirred in the circumferential direction along with the rotation of the first stirring member 803, the developer conveyed in the axial direction in the direction opposite to the conveying direction by the second stirring member 803 is sequentially passed through the developer supply and recovery member 809. To the developer carrying member 800.

  On the other hand, the developer that has been removed from the developer carrier 800 and has been subjected to the action of the developer supply / recovery member 809 is received and conveyed by the first stirring member 803, and again through the passage 821. The second stirring member 805 is acted on and the above motion is repeated for a necessary time.

  The toner in the developer is used for the development process and consumed. However, the developer after the development process is detected by an appropriate toner concentration detection sensor, and based on the detected value, unused toner (hereinafter referred to as new toner). By supplying a toner) from a toner replenishing mechanism (not shown) through a toner supply port 813, a developer having a constant toner concentration can be maintained.

  The toner supply port 813 has an almost intermediate position where the first stirring member 803 and the third stirring member 807 face each other (as shown in the sectional view of FIG. 4, the first stirring member 803 and the third stirring member 807 On the cover 812 corresponding to an appropriate position on the upstream side (in the opposing axial region) in the developer transport direction by the first stirring member. Is provided.

  The toner replenishing mechanism is provided, for example, on the apparatus main body side and above the toner supply port 813.

  The position of the toner supply port 813 on the upstream side in the protruding region as described above is intended to achieve effective mixing and stirring even when the axial length of the third stirring member 807 is short. It is.

  Therefore, when the third stirring member has a sufficient length, it is sufficient that the third agitating member is not so upstream, but even in that case, the amount of charge due to the uniform dispersion of the new toner in the developer and the friction of the developer is sufficient. In consideration of the provision and the like, it is preferable that it is on the upstream side.

  The supplied toner is efficiently stirred with the developer by the rotation of the first stirring member 803 and the third stirring member 807.

  That is, the first stirring member 803 and the third stirring member 807 are rotated in such a manner that the peripheral surfaces move in the forward direction from the upper side to the lower side when viewed from the opposing proximity point of the first stirring member 803 and the third stirring member 807 (for example, from the screw When the attention is paid to one point on the peripheral surface of the stirring member, it means that the one point reaches the proximity point from above with respect to the proximity point and rotates around the axis so as to come out downward) The toner can be quickly submerged in the developer.

  As described above, even when new toner is replenished depending on the rotation direction of the third agitating member and the first agitating member, the toner can be well dispersed and the charge rising can be performed satisfactorily. The member 807 can stir the developer for a long time.

  Further, since sufficient agitation can be performed in the circumferential direction of the agitating member without reducing the developer conveyance speed, for example, a developer having a uniform toner concentration in the axial direction of the second agitating member can be obtained in a short time. And it becomes possible to obtain easily.

  The toner used in the developing device preferably has a volume average particle size of 3 to 5 μm, and such a small particle size toner forms a toner image having high resolution and excellent fine line reproducibility. In addition, a toner image having a stable image density can be formed in the solid portion (solid image portion).

  The toner having a small particle diameter can be produced by, for example, a polymerization method.

  The carrier is preferably 5 × Dt to 10 × Dt [μm] when the volume average particle diameter of the toner is Dt [μm].

  By using a carrier having a volume average particle size of 5 to 10 times the volume average particle size of the toner, the charge imparting performance of the carrier surface can be improved even when a small particle size toner is used, As a result, the occurrence of fogging and toner scattering can be suppressed, and a uniform image density and a fine high-quality image can be obtained.

  Further, in the image forming apparatus described above, the developing process by the developing device 8 is performed in a state adjusted to the operation setting conditions satisfying the following conditions (A) and (B).

Condition (A); W ≧ M × V × L / 1000
Condition (b); R ≦ 600
In the above conditions (a) and (b), V is the peripheral speed [mm / sec] of the image carrier, and M is the maximum amount of adhesion per unit area of the toner image formed on the image carrier [mg / cm ^2]. ], L is the maximum width [mm] of the toner image in the direction (axial direction) orthogonal to the moving direction of the image carrier, and W is the developer movement amount [g] in the rotation axis direction of the developer carrier by the second stirring member. / Sec] and R indicate the rotation speed [rpm] of the second stirring member, respectively.

  In the first embodiment of the developing device, since the first stirring member and the second stirring member have substantially the same developer conveying ability on the rotation shaft, the W and R are the developers of the first stirring member. It can also be said that this is the amount of movement of the first stirring member.

  When the developer movement amount (developer transport amount) W in the rotation axis direction by the second stirring member 803 is excessively small, as a result, in the developer supply region on the downstream side in the developer transport direction of the developer supply and recovery member. The toner concentration in the developer is lowered, and it becomes difficult to supply a sufficient amount of toner to the development area, and image density unevenness is likely to occur.

  In addition, when the number of rotations of the second stirring member 803 is excessive, the developer is likely to be deteriorated by heat generated at the shaft portion of the second stirring member 803 and a high-quality image can be formed. It becomes difficult.

  In other words, the developer in a state where there is no toner density unevenness in the axial direction of the developer carrying member by performing the development process in a state satisfying the specific conditions (a) and (b) of the image forming apparatus. Since the developer can be supplied to the development area through the rotation of the developer carrying member, an image having a uniform image density without image density unevenness can be formed.

  Further, by setting the rotation speed of the second stirring member to 600 rpm or less, it is possible to prevent the developer from being deteriorated by the heat generated when the second stirring member is rotated at a high speed (the rotation speed and the development). The same can be said for the first stirring member in terms of the agent deterioration).

  As described above, according to the image forming apparatus having the above-described configuration, the toner and the carrier are sufficiently mixed and agitated to obtain sufficient charge rising characteristics of the toner, and the developer is uniform in the axial direction. The toner is supplied to the development area with a high toner density.

  Therefore, for example, when a developer in which a large amount of toner is consumed and replenished by continuously outputting images with a high printing rate is used, or the number of images formed per minute (number of printed sheets) is 50 sheets. Even when image formation is performed at such a high process speed, fog or toner scattering does not occur, and a high-quality image without image density unevenness can be formed.

  Although the developer supply / recovery member is provided in the above-described embodiment, the developer supply / recovery member can be eliminated, and the first stirring member can be configured as a dual-purpose member that is also used as the developer supply / recovery member. .

  Next, a specific configuration example of a rotating member that can be used as a stirring member will be described with reference to FIGS.

  In the figure, the same reference numerals are assigned to the same members as those already described. Further, the rotating member refers to a single member before being incorporated into the developing device, which has a configuration that can be used as an agitating member or a developer supply member, and the assembled rotating member includes a first agitating member and a second agitating member depending on its position. Although referred to as a stirring member or the like, for the sake of convenience, the terms “rotating member” and “stirring member” are not distinguished here.

  FIG. 5 is a schematic diagram showing a first example of the agitating member. As described above, a predetermined pitch (screw pitch) is provided in the axial direction over the entire circumference of the outer peripheral surface of the shaft (hereinafter also referred to as a rotating shaft) J. p, a rotating member composed of a spiral rib (screw) 850 formed with a predetermined direction (shown in one direction in the figure).

  For example, when the developer transport capability of the spiral rib having the pitch p is used as a reference, if the developer transport capability is desired to be lower than that, the pitch p1 is set to be smaller than the pitch p. The developer conveying ability in the direction of the rotation axis can be lowered. Conversely, if the pitch p2 is larger than the pitch p, the developer conveying ability in the direction of the rotation axis can be increased.

  The stirring member of the second example shown in FIG. 6 includes a plurality of plate-like members provided on the rotation axis J and inclined in the first direction, and a plurality of plate-like members provided inclined in the second direction. It has a member.

  More specifically, for example, the plate-like members 851 and 852 made of semi-elliptical plates are inclined in different directions at the axial center with respect to the same plane perpendicular to the rotational axis J on the outer peripheral surface of the rotational axis J. And a plurality of such sets are arranged in the axial direction at a predetermined pitch p.

  The attachment angles α1 and α2 of each plate-like member with respect to the rotation axis J may be the same size or different, and can be appropriately determined according to the purpose.

  The stirring members of the third to fifth examples shown in FIGS. 7 to 9 have the basic structure of the stirring member shown in FIG. 5, but further increase the developer stirring ability.

  The stirring member shown in FIG. 7 is on the outer periphery of the rotating shaft J, on the outer periphery of the rotating shaft J, and on the outer periphery of the rotating shaft J and the spiral rib 850 formed at a pitch p having a predetermined size in the axial direction. A plate-like rib (vertical blade) 855 including a rod-like shape is provided so as to extend outward in the radial direction.

  The ribs 855 are provided one for each pitch p of the spiral ribs 850, and are provided in a line (linearly) in the direction of the rotation axis.

  However, the rib 855 can be provided in the axial direction with the phase shifted on the rotation axis J when the drawing is viewed from the side.

  The stirring member shown in FIG. 8 is on the outer periphery of the rotating shaft J and on the outer periphery of the rotating shaft J, and the spiral rib 850 formed at a pitch p having a predetermined size in the axial direction. Rod-like or plate-like ribs (vertical blades) 856 provided in a row in the direction of the rotation axis, and the ribs 856 are configured in a plurality of rows.

  For example, when the figure is viewed from the side, the ribs 856 have a four-row arrangement in which the phase is shifted by 90 degrees in the circumferential direction of the rotation axis J.

  The length (meaning width) W of the rib 856 in the rotation axis direction is configured to be larger than the width W of the rib 855 shown in FIG. 7, but the size, the number of rows, etc. of the width W are intended. Anything can be achieved, and the degree of freedom in design is wide.

  The stirring member shown in FIG. 9 includes a spiral rib 850 that is formed on the entire outer peripheral surface of the rotating shaft J and has a pitch p of a predetermined size in the axial direction, and is provided at the outer peripheral edge of the spiral rib. Is formed with a notch 857 penetrating in the axial direction.

  For example, when the figure is viewed from the side, the notches 857 have a two-row arrangement in which the phases are shifted by 180 degrees in the circumferential direction of the rotation axis J. In the drawing, U indicates the length (meaning width) of the notch in the circumferential direction, and t indicates the length of the notch in the radial direction.

  Next, a sixth example and a seventh example of a stirring member having a developer stirring ability higher than that of the stirring member described so far will be described with reference to FIGS.

  The agitating member shown in FIG. 10 rotates over the entire outer peripheral surface of the rotating shaft J and through the spiral rib 850 formed at a predetermined pitch p in the axial direction and the outer peripheral edge of the spiral rib. And plate-like ribs 858 extending linearly in the direction of the axis J.

  In this example, the ribs are provided at two locations (upper edge portion and lower edge portion in the figure) that are the objects of the axis.

  The agitating member shown in FIG. 11 has the same basic configuration as that of FIG. 6 and is semi-elliptical on the outer peripheral surface of the rotation axis J and in different directions at the axis center with respect to the same plane perpendicular to the rotation axis. The plate-like members 851 and 852 made of plates are provided to be inclined, and a plurality of such sets are arranged in the axial direction at a predetermined pitch p, and the outer peripheral edges of the plate-like members 851 and 852 A plate-like rib 858 extending linearly in the direction of the rotation axis J is provided.

  In this example, four plate-like ribs 858 are provided at equal intervals in the circumferential direction.

  These agitating members rotate around the rotation axis J to agitate the developer in the circumferential direction in the process of transporting the developer in the axial direction, and plate-like ribs as auxiliary agitating members Even at 858, stirring is performed in the circumferential direction.

  As described above, according to the developing device provided with the stirring member provided with the plate-like rib serving as an auxiliary member for stirring, the above-described operation and effect can be obtained more reliably, and due to poor charging of the toner. Occurrence of fogging and toner scattering can be further suppressed.

  In addition, it is possible to more reliably suppress the occurrence of image density unevenness due to the non-uniformity of the toner density in the axial direction of the developer supplied to the developing carrier.

  Therefore, according to the image forming apparatus provided with such a developing device, the developer containing the toner having the desired charge amount and having a uniform toner density is sufficiently agitated with sufficient agitation. Since the latent image on the photosensitive drum is developed by the developer in the direction, problems such as toner scattering, fogging, and image density unevenness can be suppressed, and a higher quality image can be produced.

  In the above, the embodiment of the image forming apparatus according to the present invention has been described as an image forming apparatus capable of producing a color image having a plurality of developing devices. It can also be enjoyed when applied to a conventional image forming apparatus.

  Next, an image forming apparatus according to the second embodiment will be described.

  The image forming apparatus shown in FIG. 12 has toner recycling means (toner recycling apparatus) that collects toner removed from the photosensitive drum after transfer, and finally returns the toner to the developing apparatus for reuse.

  The image forming apparatus shown in FIG. 12 is composed of a monochrome digital copying machine, and includes a basic configuration as a copying machine, such as an automatic document feeder, an image reading unit, an image forming unit, a paper feeding unit, a fixing device, and the like. However, these can be understood from the drawings and explanations relating to the first embodiment, and the developing device 8 has basically the same configuration as that of the first embodiment. The main parts are only shown schematically.

  Further, in the figure, the same reference numerals are assigned to the same members (means) as those already described.

  In the figure, 310 is a photosensitive drum as an image carrier, 320 is a charger, 330 is an exposure optical system (writing means) including a laser light source, 8 is a developing device, 350 is a cleaning device, and P is paper.

  A transfer electrode and a separation electrode are provided between the developing device 8 and the cleaning device 350 in the rotational direction of the photosensitive drum.

  The cleaning device 350 has cleaning means including a blade 352 that contacts the surface of the photoconductive drum 310 in a counter direction at an upper position in the container 351 and toner removed by the blade 352 (hereinafter referred to as recycling). A rotatable collection member 353 made of a screw that conveys toner (also referred to as toner) in a predetermined direction (front side in the drawing) in the axial direction of the photosensitive drum is provided at a lower position in the container 351.

  Reference numeral 9 denotes a toner recycling means, which receives the recycled toner transported and collected by the collecting member 353 and transports it toward the developing device 8, and is a rotatable transporting means 901 made of a screw (for convenience, two points) (Shown with a chain line).

  The basic shapes of the recovery member 353 and the conveying means 901 are the same as those shown in FIG.

  The conveying means 901 is built in a cylindrical outer frame 903 (shown by a two-dot chain line for the sake of convenience), and the recycled toner is supplied to the developing device 8 at the tip of the outer frame 903. The opening 905 is aligned with the recycled toner supply port 825 provided on the cover 812 of the developing device 8 so that there is no toner leakage.

  The recycled toner supply port 825 is in a range where the first agitating member 803 and the third agitating member 807 are opposed to each other in the protruding region 802, and when viewed from the side, is approximately at the middle position between both agitating members. The first agitating member is provided on the cover 812 corresponding to an appropriate position on the upstream side of the toner supply port 813 in the developer transport direction.

  The positional relationship between the toner supply port 813 and the recycled toner supply port 825 in the longitudinal direction of the developing device 8 is shown in FIG. 13 which is a schematic diagram of the developing device, but the distance between the two is not particularly limited. However, it is practically preferable to provide the recycled toner supply port 825 at an upstream position about 5 to 30 mm from the toner supply port.

  In the embodiment, the effective length for transferring the developer in the axial direction of the rotating member is 440 mm, and the effective length in the protruding region 802 is 110 mm.

  The recycled toner is supplied with its supply amount adjusted so that the ratio of recycled toner to new toner in the developer (recycled toner ratio) is maintained at 50% by mass or less.

  With the developing device having such a configuration, the mixing and stirring time of the recycled toner, which is poor in fluidity and lower in chargeability than the new toner, can be increased. And the occurrence of fogging and toner scattering due to poor charging of the toner can be suppressed, and the occurrence of uneven image density in image formation can be suppressed.

  Further, in the image forming apparatus including the developing device having the above-described configuration, a developer in which a large amount of toner consumption and replenishment of toner including recycled toner are repeatedly performed by continuously outputting an image with a high printing rate is used. Even when image formation is performed at a high process speed such that the number of image formations per minute is 50 or more, occurrence of fogging and toner scattering can be suppressed, and uneven image density can be achieved. Therefore, a high-quality image having a uniform density can be formed.

  The series of embodiments of the developing device and the image forming apparatus according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be added.

  Next, second and third embodiments of the developing device will be described with reference to FIGS.

  Since these developing devices are based on the configuration shown in FIG. 2 including the arrangement of the stirring members and the rotation direction, only different parts will be described briefly.

  The operational effects achieved by the developing device having the illustrated configuration are the same as those of the developing device shown in FIG.

  In the developing device shown in FIG. 14, the first stirring member 803 has two stirring portions 1A and 1B having different developer transport capabilities.

  Specifically, the stirring portion (referring to a portion corresponding to the protruding region 802) 1A located on the downstream side when viewed in the developer transport direction by the first stirring member 803 is lower than the second stirring member 805. The stirring portion 1B has substantially the same developer transport capability as the second stirring member, and the developer transport direction is opposite to the transport direction by the second stirring member. It is set.

  Further, the third stirring member 807 in the present embodiment has a capability of transporting the developer in the rotation axis direction, and the capability is the same as or lower than the stirring portion 1A. is there.

  Further, the developer conveying direction by the third stirring member 807 is the same direction as the first stirring member 803, that is, the opposite direction to the developer conveying direction by the second stirring member 805.

  In the developing device shown in FIG. 15, the developer carrying capacity of the stirring portion 1B located on the upstream side of the first stirring member 803 when viewed in the developer carrying direction by the first stirring member 803 is the same as that of the second stirring member 805. Although it is almost the same as the developer conveying capability, the conveying capability of the stirring portion 1A located on the downstream side is configured to be lower than the developer conveying capability by the stirring portion 1B or the second stirring member 805. .

  Further, the developer conveyance direction in the stirring portion 1A is the opposite direction to the stirring portion 1B, in other words, the same direction as the developer conveyance direction by the second stirring member 805.

  On the other hand, the third agitating member 807 has a larger conveying ability than the developer conveying ability of the agitating part 1B or the second agitating member 805, and the developer conveying direction is the development by the agitating part 1A or the second agitating member 805. It is comprised so that it may become a reverse direction with the agent conveyance direction.

  The reason why the developer conveying ability and the conveying direction of the stirring portion 1A or the third agitating member 807 are determined as described above is to allow the developer to be circulated and conveyed without lowering the developer conveying speed. In addition, it is intended to increase the stirring time of the new toner or the recycled toner and the circulating developer.

  In the above embodiment, the developer supply / recovery member 809 can be omitted from the configuration. However, when used, it is preferable that the developer is not conveyed in the direction of the rotation axis.

  For example, in a finished state, a blade portion having a predetermined length, width, and thickness is provided on the peripheral surface of the rotating shaft. A developer supply / recovery member which does not exist can be obtained.

  In the three forms of the developing device described above, the outer diameter of the third stirring member 807 is set larger than the outer diameter of the first stirring member 803, the rotational speed is set larger, or By setting the speed large, the developer stirring effect can be further enhanced, and the performance can be improved.

Next, experimental examples conducted for confirming the effects of the present invention will be described.
[Production of rotating member]
A rotating member used as a stirring member was produced as follows.

Among the following, regarding the “length in the direction of the rotational axis excluding the shaft portion”, in the case of the rotating member used as the first stirring member according to the present invention, the length of the portion corresponding to the stirring portion 1A is 110 mm. The part 1B is 330 mm, and the length when used as the third stirring member is 110 mm, which is the same as the stirring part 1A.
(Rotating member AA)
As shown in FIG. 5, a left-handed spiral rib (screw) is formed on the outer peripheral surface of the shaft member, and the outer peripheral surface of the shaft member spans a length of 30 mm on the downstream side in the developer conveyance direction by the spiral rib. On the top, four flat blade members are provided so as to extend outward in the radial direction to form a paddle shape, and further, disk-shaped flange members F having an outer dimension of 24 mm are provided at both ends of the rotating member. Rotating member configured.

  The specifications of the rotating member AA are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, pitch of spiral rib (p): 30 mm, thickness of spiral rib: 1 mm
(Rotating member CC)
The rotating member AA has the same configuration as the rotating member AA except that the spiral rib is formed in a right-handed manner.
(Rotating member EE)
As shown in FIG. 9, a left-handed spiral rib (screw) is formed on the outer peripheral surface of the shaft member, a notch is provided on the outer peripheral edge of the spiral rib, and the spiral rib is Four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm downstream in the transport direction of the developer so as to extend outward in the radial direction to form a paddle shape, and external shapes are provided at both ends of the rotating member. A rotating member having a configuration in which a disk-shaped flange member F having a dimension of 24 mm is provided.

  The specifications of the rotating member EE are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, pitch of spiral rib (p): 30 mm, thickness of spiral rib: 1 mm, Radial length of notch (t): 5 mm, circumferential length of notch (U): 2 mm, notch: 4 locations per pitch (equally spaced)
(Rotating member GG)
As shown in FIG. 7, a left-handed spiral rib (screw) is formed on the outer peripheral surface of the shaft member, and a plurality of plate-like ribs (vertical blades) extending radially outward are provided in the longitudinal direction of the shaft. And four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm downstream in the developer conveyance direction by the spiral ribs so as to extend radially outward to form a paddle shape. In addition, a rotating member having a configuration in which disk-shaped flange members F having an outer dimension of 24 mm are provided at both ends of the rotating member.

  The specifications of the rotating member GG are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, pitch of spiral rib (p): 30 mm, thickness of spiral rib: 1 mm, Arrangement of plate-like ribs: one per pitch (center position between screw pitches), length of plate-like ribs in the axial direction (W): 3 mm, length of plate-like ribs in radial direction (h ): 8 mm, plate-like rib thickness: 1 mm
(Rotating member II)
As shown in FIG. 8, a left-handed spiral rib (screw) is formed on the outer peripheral surface of the shaft member, and a plurality of plate-like ribs (vertical blades) extending radially outward are provided in the longitudinal direction of the shaft. And four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm downstream in the developer conveyance direction by the spiral ribs so as to extend radially outward to form a paddle shape. In addition, a rotating member having a configuration in which disk-shaped flange members F having an outer dimension of 24 mm are provided at both ends of the rotating member.

  The specifications of the rotating member II are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, pitch of spiral rib (p): 30 mm, thickness of spiral rib: 1 mm, Arrangement of plate-like ribs: four at regular intervals per pitch, length (W) in the axial direction of plate-like ribs: 12 mm, length in radial direction of plate-like ribs (h): 8 mm, plate Rib thickness: 1mm
(Rotating member JJ)
The rotating member II has the same configuration as the rotating member II except that the length of the plate-like rib in the axial direction is 20 mm.
(Rotating member KK)
As shown in FIG. 10, a left-handed spiral rib (screw) is formed on the outer peripheral surface of the shaft member, and a plate-like rib extending in the axial direction without a break on the outer peripheral edge of the spiral rib. And four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm downstream in the developer conveyance direction by the spiral ribs so as to extend radially outward to form a paddle shape. In addition, a rotating member having a configuration in which disk-shaped flange members F having an outer dimension of 24 mm are provided at both ends of the rotating member.

  The specifications of the rotating member KK are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, pitch of spiral rib (p): 30 mm, thickness of spiral rib: 1 mm, Radial length of plate-like rib (t): 3 mm, plate-like rib thickness: 1 mm, plate-like rib mounting location: two axially symmetric locations (rotating member LL)
The rotating member KK has the same configuration as the rotating member KK except that the radial length (t) of the plate-like rib is 5 mm.
(Rotating member MM)
The rotating member KK has the same configuration as the rotating member KK except that four plate-shaped ribs are provided at equal intervals on the outer peripheral edge of the spiral rib.
(Rotating member WW)
As shown in FIG. 6, a first stirring unit and a second stirring unit configured by providing a plurality of semi-elliptical plate-like members so as to be inclined in different directions with respect to a plane perpendicular to the shaft member. And a rotating member having a disk-like flange member F having an outer dimension of 24 mm at both ends of the rotating member.

  The specifications of the rotating member WW are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, thickness of plate member: 1 mm, shaft of plate member constituting first stirring portion Mounting angle (α1): + 45 °, mounting angle (α2) with respect to the axis of the plate-like member constituting the second stirring section: −45 °, plate-like member arrangement pitch: 25 mm
(Rotating member XX)
As shown in FIG. 11, a first stirring unit and a second stirring unit configured by providing a plurality of semi-elliptical plate-like members so as to be inclined in different directions with respect to a plane perpendicular to the shaft member. And on the outer peripheral edge of the plate-like member constituting the first stirring unit and the second stirring unit and extending in the axial direction at four positions that are equally spaced in the circumferential direction. A rotary member having a configuration in which plate-like ribs are provided and disk-like flange members F having an outer dimension of 24 mm are provided at both ends of the rotary member.

  The specifications of the rotating member XX are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm, outer diameter of shaft member: 6 mm, thickness of plate member: 1 mm, shaft of plate member constituting first stirring portion Mounting angle (α1): + 45 °, mounting angle (α2) with respect to the axis of the plate-like member constituting the second stirring section: −45 °, pitch of plate-like member (p): 25 mm, plate-like rib Radial length (t): 3 mm, plate-like rib thickness: 1 mm
(Rotating member QQ)
As shown in FIG. 16, plate-like ribs (flat blade members) 859 extending radially outward and in the longitudinal direction of the shaft are provided from four equally spaced locations in the circumferential direction of the rotating shaft to form a cross paddle. A rotating member having a configuration.

  The specifications of the rotating member QQ are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 360 mm, outer diameter of shaft member: 6 mm, thickness of plate member: 1 mm, radial length of plate member (h): 9mm
(Rotating member D)
The rotating member AA has the same configuration as the rotating member AA except that the spiral rib is formed in a right-handed manner, the screw pitch of the spiral rib is 40 mm, and the axial length is 110 mm. A rotating member having.
(Rotating member D2)
In the rotating member D, the rotating member has the same configuration as the rotating member D except that the maximum outer diameter is set to be as large as 30 mm.
(Rotating member L)
The rotating member LL has the same configuration as the rotating member LL except that the axial length excluding the shaft portion is 110 mm.
(Rotating member L2)
A rotating member having the same configuration as that of the rotating member L except that the rotating member L has a large maximum outer diameter of 30 mm.
(Rotating member O)
In the rotating member LL, the rotating member has the same configuration as the rotating member LL except that the axial length excluding the shaft portion is 110 mm and the spiral rib is clockwise.
(Rotating member 02)
A rotating member having the same configuration as that of the rotating member O except that the maximum outer diameter of the rotating member O is 30 mm.
(Rotating member P)
In the rotating member MM, the rotating member has the same configuration as the rotating member MM except that the axial length excluding the shaft portion is 110 mm and the spiral rib is right-handed.
(Rotating member P2)
In the rotating member P, the rotating member has the same configuration as the rotating member P except that the maximum outer diameter is set to a large diameter of 30 mm.
(Rotating member Q)
The rotating member QQ has the same configuration as the rotating member QQ except that the axial length excluding the shaft portion is 110 mm.
(Rotating member Q2)
A rotating member having the same configuration as the rotating member Q except that the rotating member Q has a large maximum outer diameter of 30 mm.
(Rotating member R)
As shown in FIG. 17, a plurality of plate-like members composed of circular plates 853 provided so that the notches are alternately opposite to each other, and shafts provided at four positions at equal intervals in the circumferential direction of the plate-like member A rotating member having a plate-like rib 858 extending in the direction and having a disk-like flange member F having an outer dimension of 24 mm at both ends of the rotating member.

  The specifications of the rotating member R are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 110 mm, outer diameter of shaft member: 6 mm, thickness of plate member: 1 mm, mounting angle of plate member with respect to shaft: 90 °, plate Pitch of the plate-like members: 25 mm, center angle of the plate-like members: 270 °, radial length of the plate-like ribs (t): 5 mm, thickness of the plate-like ribs: 1 mm, attachment points of the plate-like ribs: 4 Location (equally spaced in the circumferential direction)
(Rotating member R2)
The rotating member R has the same configuration as the rotating member R except that the maximum outer diameter is as large as 30 mm.
(Rotating member S)
As shown in FIG. 18, a plurality of elliptical plate-like members are arranged in the axial direction, and disk-like flange members F having an outer dimension of 24 mm are provided at both ends of the rotating member. Rotating member configured.

  The specifications of the rotating member S are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 110 mm, outer diameter of shaft member: 6 mm, thickness of plate member: 1 mm, attachment angle of plate member to shaft: 45 °, plate Arrangement pitch: 25 mm
(Rotating member S2)
A rotating member having the same configuration as that of the rotating member S except that the rotating member S has a maximum outer diameter of 30 mm.
(Rotating member T)
As shown in FIG. 19, a plurality of elliptical plate-like members 854 are arranged in the axial direction, and plate-like ribs 858 extending in the axial direction are provided at equal intervals in the circumferential direction. A rotating member having a configuration in which a disc-shaped flange member F having an outer dimension of 24 mm is provided at both end portions.

  The specifications of the rotating member T are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 110 mm, outer diameter of shaft member: 6 mm, thickness of plate member: 1 mm, attachment angle of plate member to shaft: 45 °, plate Pitch of the plate-like members: 25 mm, radial length of the plate-like ribs (t): 3 mm, thickness of the plate-like ribs: 1 mm, attachment points of the plate-like ribs: four locations (equal intervals in the circumferential direction)
(Rotating member T2)
A rotating member having the same configuration as that of the rotating member T except that the rotating member T has a maximum outer diameter of 30 mm.
(Rotating member U)
In the rotating member WW, the axial length excluding the shaft portion is 110 mm, and the mounting angle of the plate-like member with respect to the shaft is (α1): −45 °, (α2): + 45 °.
A rotating member having the same configuration as the rotating member WW except for the above.
(Rotating member U2)
The rotating member U has the same configuration as that of the rotating member U except that the maximum outer diameter is set to a large diameter of 30 mm.
(Rotating member V)
In the rotating member XX, the axial length excluding the shaft portion is set to 110 mm, and the mounting angle of the plate-like member with respect to the shaft is (α1): −45 °, (α2): + 45 °.
A rotating member having the same configuration as the rotating member XX except for the above.
(Rotating member V2)
The rotating member V has the same configuration as the rotating member V except that the maximum outer diameter is set to a large diameter of 30 mm.
(Rotating member EA)
As a stirring portion 1A, a spiral rib with a notch portion (left-handed) shown in FIG. 9 and a spiral rib (left-handed) shown in FIG. 5 as a stirring portion 1B are integrally provided and developed. Four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm downstream in the overall conveying direction of the agent so as to extend radially outward to form a paddle shape. A rotating member having a configuration in which a disc-shaped flange member F having an outer dimension of 24 mm is provided at both ends.

  The specifications of the rotating member EA are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm (however, stirring portion 1A is 110 mm, stirring portion 1B is 330 mm), shaft member outer diameter: 6 mm, pitch of spiral rib (P): 30 mm, thickness of spiral rib: 1 mm, radial length of cutout portion (t): 5 mm, circumferential length of cutout portion (U): 2 mm, cutout portion: 4 locations per pitch ( Circumferentially equidistant)
(Rotating member FA) A rotating member having the same configuration as the rotating member EA except that the pitch (p) of the spiral ribs in the stirring portion 1A is 20 mm in the rotating member EA.
(Rotating member HA)
As the stirring portion 1A, a spiral rib (left-handed) including the plate-like rib shown in FIG. 7 and a spiral rib (left-handed) shown in FIG. 5 are integrally provided as the stirring portion 1B. And, on the outer peripheral surface of the shaft member extending 30 mm in length downstream in the overall developer conveyance direction, four flat blade members are provided so as to extend outward in the radial direction to form a paddle shape, A rotating member having a configuration in which disk-shaped flange members F having an outer dimension of 24 mm are provided at both ends of the rotating member.

  The specifications of the rotating member HA are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm (however, stirring portion 1A is 110 mm, stirring portion 1B is 330 mm), shaft member outer diameter: 6 mm, pitch of spiral rib (P): Stirring portion 1A is 20 mm, stirrer 1st position B is 30 mm, spiral rib thickness: 1 mm, radial length of plate rib (h): 5 mm, axial length of plate rib Thickness (W): 3 mm, plate-like rib arrangement: one per pitch (center position between screw pitches), plate-like rib thickness: 1 mm
(Rotating member KA)
A spiral rib (left-handed) including a plate-like rib extending in the axial direction shown in FIG. 10 as the stirring portion 1A, and a spiral rib (left-handed) shown in FIG. 5 as the stirring portion 1B. And four flat blade members are provided on the outer peripheral surface of the shaft member that extends 30 mm downstream in the overall developer transport direction so as to extend radially outward. A rotating member having a paddle shape and a disc-shaped flange member F having an outer dimension of 24 mm provided at both ends of the rotating member.

  The specifications of the rotating member KA are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm (however, stirring portion 1A is 110 mm, stirring portion 1B is 330 mm), shaft member outer diameter: 6 mm, pitch of spiral rib (P): 30 mm, thickness of spiral rib: 1 mm, radial length of plate-like rib (t): 3 mm, axial length of plate-like rib: 110 mm, arrangement of plate-like rib: shaft 2 positions of target, thickness of plate-like rib: 1mm
(Rotating member NA)
In the rotating member KA, the rotating member has the same configuration as the rotating member KA except that the spiral rib of the stirring portion 1A is wound clockwise and the pitch of the spiral rib of the portion is 20 mm.
(Rotating member WA)
As the stirring portion 1A, a first stirring portion configured by providing a plurality of semi-elliptical plate-like members so as to be inclined in different directions with respect to a plane perpendicular to the shaft member shown in FIG. 5 as a stirring portion 1B, and integrally with the spiral rib (left-handed) shown in FIG. 5, and the length on the downstream side in the overall developer transport direction. On the outer peripheral surface of the shaft member extending over 30 mm, four flat blade members are provided so as to extend radially outward to form a paddle shape, and disk-shaped flanges having an outer dimension of 24 mm at both ends of the rotating member A rotating member having a configuration in which the member F is provided.

  The specifications of the rotating member WA are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft part: 440 mm (however, the stirring part 1A is 110 mm, the stirring part 1B is 330 mm), and the plate member constituting the first stirring part is attached to the shaft Angle (α1): + 45 °, Mounting angle (α2) with respect to the axis of the plate-like member constituting the second stirring unit: -45 °, plate-like member thickness: 1 mm, plate-like member arrangement pitch: 25 mm, spiral Rib pitch: 30 mm, spiral rib thickness: 1 mm
(Rotating member XA)
As shown in FIG. 11, as the stirring portion 1 </ b> A, a first stirring portion configured by providing a plurality of semi-elliptical plate-like members so as to be inclined in different directions with respect to a plane perpendicular to the shaft member And the second stirrer, and on the outer peripheral edges of the plate-like members constituting the first stirrer and the second stirrer, at four positions equidistant in the circumferential direction. 5 has a configuration in which plate-like ribs extending in the direction are provided, and integrally has a helical rib (left-handed) shown in FIG. 5 as the stirring portion 1B, and the developer is transported as a whole. Four flat blade members are provided on the outer circumferential surface of the shaft member extending 30 mm downstream in the direction so as to extend outward in the radial direction to form a paddle shape, and external dimensions are provided at both ends of the rotating member. With a 24 mm disk-shaped flange member F Rotating member.

  The specifications of this rotating member are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis excluding shaft portion: 440 mm (however, stirring portion 1A is 110 mm, stirring portion 1B is 330 mm), relative to the axis of the plate-like member constituting the first stirring portion Mounting angle (α1): + 45 °, mounting angle (α2) with respect to the axis of the plate member constituting the second stirring section: −45 °, plate member thickness: 1 mm, plate member arrangement pitch: 25 mm, The radial length (t) of the plate-like rib: 3 mm, the axial length of the plate-like rib: 110 mm, the thickness of the plate-like rib: 1 mm, the pitch of the helical rib: 30 mm, the length of the helical rib Thickness: 1mm
(Rotating member OC)
As the stirring portion 1A, a spiral rib (however, right-handed) shown in FIG. 10 is formed on the outer peripheral surface of the shaft member, and on the outer peripheral edge of the spiral rib, a plate shape extending in the axial direction without a break. 5B, and the stirring portion 1B is formed of a spiral rib (but right-handed) shown in FIG. 5 and is long on the downstream side as viewed in the overall developer conveyance direction. On the outer peripheral surface of the shaft member extending over 30 mm, four flat blade members are provided so as to extend radially outward to form a paddle shape, and disk-shaped flanges having an outer dimension of 24 mm at both ends of the rotating member A rotating member having a configuration in which the member F is provided.

  The specifications of the rotating member OC are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 440 mm (however, the stirring portion 1A is 110 mm, the stirring portion 1B is 330 mm), the pitch of the spiral ribs (p): 30 mm, spiral Rib thickness: 1 mm, radial length of plate-like rib member (t): 5 mm, axial length of plate-like rib: 110 mm, arrangement of plate-like ribs: two axially symmetric, plate-like Rib thickness: 1mm
(Rotating member YE)
As a stirring part 1A, a spiral rib (left-handed) including a plate-like rib extending in the axial direction shown in FIG. 10 as a stirring part, and as a stirring part 1B, a spiral rib with a notch part shown in FIG. (Left-handed) and four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm in length in the overall developer transport direction so as to extend radially outward. And a rotating member having a configuration in which a disk-shaped flange member F having an outer dimension of 24 mm is provided at both ends of the rotating member.

  The specifications of the rotating member YE are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis direction excluding shaft portion: 440 mm (however, stirring portion 1A is 110 mm, stirring portion 1B is 330 mm), spiral rib pitch (p): plate-like rib With a notch, 30 mm, spiral rib thickness: 1 mm, radial length of plate-like rib member (t): 3 mm, axial length of plate-like rib: 110 mm, plate-like Rib arrangement: two axially symmetric locations, plate-like rib thickness: 1 mm, radial length (t) of cutout portion: 5 mm, circumferential length of cutout portion (U): 2 mm, cutout portion: 1 pitch 4 locations per hit (equally spaced)
(Rotating member OE)
In the rotary member YE, the spiral rib with a plate-like rib constituting the stirring portion 1A is wound clockwise, the screw pitch is 30 mm, and the radial length of the plate-like rib is 5 mm. Others are rotating members having the same configuration as the rotating member YE.
(Rotating member PE)
In the rotating member YE, the spiral ribs with plate-like ribs constituting the stirring portion 1A are wound clockwise, the screw pitch is 30 mm, and the plate-like ribs are attached at four locations that are equally distributed in the circumferential direction. A rotating member having the same configuration as that of the rotating member YE except for the above.
(Rotating member LG)
As the stirring portion 1A, a spiral rib (left-handed) including a plate-like rib extending in the axial direction shown in FIG. 10 as a stirring portion, and as a stirring portion 1B, a spiral including a plate-like rib shown in FIG. Four flat blade members extend radially outward on the outer peripheral surface of the shaft member having a length of 30 mm on the downstream side as viewed in the overall developer conveyance direction. A rotating member having a configuration in which a paddle shape is provided and a disc-shaped flange member F having an outer dimension of 24 mm is provided at both ends of the rotating member.

  The specifications of the rotating member LG are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 440 mm (however, the stirring portion 1A is 110 mm, the stirring portion 1B is 330 mm), the pitch of the spiral ribs (p): 30 mm, spiral Rib thickness: 1 mm, radial length (t) of the plate-like rib extending in the axial direction: 5 mm, attachment location of the plate-like rib extending in the axial direction: two axially symmetric plate-like shapes extending in the axial direction Rib thickness: 1 mm, radial length (h) of plate-like ribs (vertical blades): 8 mm, axial length of plate-like ribs (W): 3 mm, arrangement of plate-like ribs: 1 pitch One per hit (center position between screw pitches), plate-like rib thickness: 1 mm
(Rotating member MG)
In the rotating member LG, the radial length of the plate-like ribs extending in the axial direction constituting the stirring portion A is 3 mm, and the rotating member LG is the same except that the mounting locations are four equally distributed portions in the circumferential direction. A rotating member having the same configuration as the above.
(Rotating member WG)
As the stirring portion 1A, a first stirring portion configured by providing a plurality of semi-elliptical plate-like members so as to be inclined in different directions with respect to a plane perpendicular to the shaft member shown in FIG. 2 and a spiral rib (left-handed) including a plate-like rib shown in FIG. 7 as the stirring portion 1B, and when viewed in the overall developer conveyance direction. Four flat blade members are provided on the outer peripheral surface of the shaft member with a length of 30 mm on the downstream side so as to extend outward in the radial direction to form a paddle shape, and a circular shape having an outer dimension of 24 mm at both ends of the rotating member. A rotating member having a configuration in which a plate-like flange member F is provided.

  The specifications of the rotating member WG are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 440 mm (however, the stirring portion 1A is 110 mm and the stirring portion 1B is 330 mm), and the plate-like member constituting the first stirring portion is attached to the shaft. Angle (α1): + 45 °, Mounting angle (α2) with respect to the axis of the plate-like member constituting the second stirring unit: -45 °, plate-like member thickness: 1 mm, plate-like member arrangement pitch: 25 mm, spiral Pitch of ribs (p): 30 mm, Thickness of spiral ribs: 1 mm, Radial length (h) of plate ribs (vertical blades): 8 mm, Axial length of plate ribs (W ): 3 mm, plate-like rib arrangement: one per pitch (center position between screw pitches), plate-like rib thickness: 1 mm
(Rotating member XG)
As shown in FIG. 11, as the stirring portion 1 </ b> A, a first stirring portion configured by providing a plurality of semi-elliptical plate-like members so as to be inclined in different directions with respect to a plane perpendicular to the shaft member And the second stirrer, and on the outer peripheral edges of the plate-like members constituting the first stirrer and the second stirrer, at four positions equidistant in the circumferential direction. A plate-like rib extending in the direction and having a spiral rib (left-handed) including the plate-like rib shown in FIG. 7 as the stirring portion 1B, and a developer Four flat blade members are provided on the outer peripheral surface of the shaft member extending 30 mm downstream in the overall conveying direction to extend radially outward to form a paddle shape, and both ends of the rotating member A disc-shaped flange member F with an outer dimension of 24 mm Configuration and the rotating member.

  The specifications of this rotating member are as follows.

Maximum outer diameter (d): 24 mm, length in rotation axis excluding shaft portion: 440 mm (however, stirring portion 1A is 110 mm, stirring portion 1B is 330 mm), relative to the axis of the plate-like member constituting the first stirring portion Mounting angle (α1): + 45 °, mounting angle (α2) with respect to the axis of the plate member constituting the second stirring section: −45 °, plate member thickness: 1 mm, plate member arrangement pitch: 25 mm, Spiral rib pitch (p): 30 mm, spiral rib thickness: 1 mm, radial length (h) of plate-like rib (vertical blade): 8 mm, axial length of plate-like rib ( W): 3 mm, plate-like rib arrangement: one per pitch (center position between screw pitches), plate-like rib thickness: 1 mm
<Experimental example 1>
[Create developer]
In accordance with the configuration shown in FIGS. 2 to 4, the developing devices 1 to 6 and 18 to 22 according to the present invention in which the stirring member is constituted by the rotating member shown in Table 1 below, the developing devices 7 to 17 for comparison, and 23-25 were produced.

  The developer carrying member (developing sleeve) has an outer diameter of 30 mm and an axial length of 330 mm (magnetic brush forming width of 320 mm).

  In each of the developing devices 1 to 7 and 12 to 25, the toner supply port is formed at a position where the stirring portion 1A of the first stirring member 803 and the third stirring member face each other (cross section orthogonal to the longitudinal direction of the rotation shaft). As shown in FIG. 4, the position is above the middle of both members as shown in FIG. 4 and is 15 mm downstream from the upstream edge in the developer conveying direction by the first stirring member in the same region (protruding region 802). It is.

  Further, the toner supply port formation position in each of 8 to 11 does not have the third stirring member, but the position is the same as the position related to the developing devices 1 to 7 and the like.

  As the developer, a two-component developer having a toner concentration of 7% by mass is used for all of the developers relating to yellow toner, magenta toner, cyan toner and black toner, and 850 g is used for the developing devices 1 to 7. 8-11 were filled with 750 g, 12-17 with 850 g, and 18-25 with 1100 g of developer.

  Each of the above toners has a volume average particle diameter of 4.5 ± 0.15 μm, a CV value [a / b × 100%] indicated by the standard deviation (a) of the particle diameter distribution and the average particle diameter (b). In each color polymerized toner having a toner particle size of 18 ± 2%, large particle size silica 0.8% by mass, small particle size silica 0.2% by mass, large particle size titania 0.2% by mass, and small particle size titania 0.4%. A material obtained by externally adding mass% and calcium stearate 0.05 mass% was used.

  As for the carrier, in any developer related to each toner, an acrylic resin is coated on the surface of a ferrite particle having a volume average particle diameter of 25 μm and a saturation magnetization of 60 emu / g. What was coated in the state used was used.

  Each of the developing devices is mounted on an appropriate driving machine, and the rotation amounts of the first stirring member, the second stirring member, the third stirring unit member, and the developer supply / recovery member are set as shown in Table 1 below. The measurement was performed by measuring the mass of the developer discharged per unit time from the developer discharge port provided on the bottom surface of the housing on the downstream side of the second stirring member in the developer transport direction.

  The results are shown in Table 1 below.

  In Table 1, “the direction of movement in the first / third counter part” indicates the direction of movement of the two agitating members when viewed in the proximity of the first agitating member and the third agitating member.

  Further, as the rotation speeds of the first and second stirring members in the developing devices 1 to 6 according to the present invention, two types of rotation speeds are respectively displayed, but color images are formed for all combinations, and monochrome In the image formation, a high rotational speed including the third stirring member was used.

  However, for the developing devices 11 to 17 for comparison, for example, for color image formation, the rotation speed of the first and second stirring members was 400 rpm, and 650 rpm or 300 rpm was used for monochrome image formation.

  The results are shown in Table 2 and Table 3 described later, respectively.

[Image forming apparatus]
According to the configuration shown in FIG. 1, image forming apparatuses 1 to 25 for forming color images on which developing devices 1 to 25 are mounted were manufactured, and an image output test was performed under the following image forming conditions. <Image forming conditions>
-Process speed (V): 220 mm / sec (number of images formed per minute is 50 sheets)-Number of rotations of developer carrier (developing sleeve): adjusted within the range of 210 to 280 rpm on the photosensitive drum The toner adhesion amount (M) per unit area was 0.4 mg / cm ² .

-The closest distance between the photosensitive drum and the developing sleeve: 0.3 mm
Development bias: bias in which an AC bias (AC) component and a DC bias (DC) component are superimposed AC bias component: Vac = 1 kVpp, fac = 5 kHz, waveform = sine wave DC bias component: maximum exposure portion on the photosensitive drum In accordance with the detection result of the surface potential VL, control was performed so that Vdc = VL−500V.

・ Developer transport amount by developing sleeve: 25 ± 2 mg / cm ²
-Magnetic brush formation width in the axial direction of the developing sleeve: 320 mm
Toner replenishment control: a toner concentration sensor (permeability sensor) is provided at a position 80 mm upstream from the downstream edge in the overall developer conveying direction in the first agitating member, and a toner replenishment motor according to the detection result The drive was controlled.

-Toner replenishment speed: Max. 30 g / min
Photoconductor surface potential: Maximum exposed portion potential (VL): -50V to -100V
Charging potential (VH): Control was performed so that VH = Vdc−150 V in accordance with the set value of the DC bias component in the developing bias.

In the image output test, the image output of the following (1) to (6) is repeated four times (A4 × 2000 in total), the presence / absence of fogging of the character / line pattern, the presence / absence of character scattering, the density of the solid pattern The presence / absence of unevenness and the presence / absence of in-machine contamination were evaluated based on the following evaluation criteria. The results are shown in Table 2 below.
(1) Cyan (C) monochromatic characters / lines + halftone (10 steps) pattern (printing rate 30%) are output in succession 50 sheets.
(2) Cyan (C) single color solid pattern (printing rate 80%) is output continuously 150 sheets.
(3) Cyan (C) single-color character / line pattern (printing rate 7%) is output continuously 50 sheets.
(4) Blue (magenta (M) + cyan (C)) single-color character / line + halftone (10 steps) pattern (printing rate of 30% for both M and C) is output in 50 sheets.
(5) Continuous output of 150 solid blue solid patterns (printing rate of 80% for both M and C).
(6) Output 50 sheets of blue (magenta (M) + cyan (C)) single color characters / line patterns (printing rate 7% for both M and C) continuously.
<Evaluation criteria>
(B) Image cover:
For image fogging, the relative reflection density of the white portion of the character / line pattern when the reflection density of unused paper is 0 is measured. If the relative reflection density is 0.004 or less, “○” is given. The case where the reflection density exceeded 0.004 and was 0.006 or less was evaluated as “Δ”, and the case where the relative reflection density exceeded 0.006 was evaluated as “x”.
(B) Letter scattering:
For character scattering, the sharpness of the character outline and the state of the bleeding of the character when the 4-point “bell” character was observed in an enlarged manner were evaluated.

If the space of the “bell” character is clearly removed and the outline of the character is clear, and the toner scattering around the character is extremely small, the space portion of the “bell” and “bell” character If the toner is slightly crushed (slightly filled with toner scatter), but the toner scatter around the character is small, the space part of the letter “△” or “bell” is crushed (filled with toner scatter). In addition, the case where there is a lot of toner scattering around the character and the outline of the character is blurred is defined as “X”.
(C) Image density unevenness:
The image density unevenness was evaluated by the color difference (distance in the L * a * b * space) at any nine positions in the page of the solid pattern of cyan single color or the solid pattern of blue single color.

“○” indicates that the color difference at 9 locations for the solid pattern of cyan single color is 3 or less and 9 color differences at the solid pattern of blue color is 7 or less, 9 locations for the solid pattern of cyan single color The color difference of 3 is more than 3 and 5 or less, and the color difference of 9 places for blue solid pattern is 7 or less, or the color difference of 9 places for cyan solid pattern is 3 or less In addition, the color difference at 9 locations for the solid pattern of blue single color exceeds 7 and 9 or less is “△”, the color difference at 9 locations for the solid pattern of cyan single color exceeds 3 and the color difference of blue single color A case where the color difference at 9 locations of the solid pattern exceeded 9 was designated as “x”.
(D) In-flight dirt:
In-machine contamination was evaluated by removing the developing device after image output and visually observing the state of contamination near the developing device mounting portion.

  When no in-machine dirt is observed, or when only a slight amount of dirt is seen only on the developing device mounting portion, “○” is indicated, and slight staining is recognized near the developing device mounting portion (for example, both ends). The case was marked with “△”, and the case where the stain on the developing device mounting part was extended to the peripheral part (for example, a charger) was marked with “x”.

  The results are shown in Table 2. The developing device numbers in the table correspond to the developing device numbers in Table 1, which also correspond to the image forming device numbers described above.

<Experimental example 2>
[Production of development device]
Each of the developing devices 1 to 25 used in Experimental Example 1 has the same configuration as the developing devices 1 to 25 except that a recycled toner supply port is formed at a position 8 mm upstream from the toner supply port. Devices 1 to 25 (displayed with the same number for easy understanding of correspondence) were produced.

  In accordance with the configuration shown in FIG. 12, image forming apparatuses 1 to 25 for forming a monochrome image having toner recycling means mounted thereon with the developing apparatuses 1 to 25 were manufactured.

  The toner recycling unit is configured by a conveyance unit for conveying the recycled toner to the developing device, and a toner conveyance amount per unit time is 30 g / min at the maximum.

  For each of the image forming apparatuses, the process speed is set to 320 mm / sec (the number of image forming sheets per minute is 65 sheets), and the rotational speeds of the stirring member and the developer supply / recovery member are shown in Table 1. The image output of the following (7) to (9) is repeated eight times under the same image forming conditions as the image forming unit related to the black (BK) toner image of Experimental Example 1 without a high rotational speed. (Total: A4 × 2000) Based on the above-mentioned evaluation criteria, an image output test is performed to evaluate the presence / absence of fogging of characters / line patterns, the presence / absence of character scattering, and the presence / absence of in-machine dirt. The presence or absence of image density unevenness in the solid pattern was evaluated based on the following evaluation criteria.

The results are shown in Table 3 below.
(7) Black (BK) single color characters / lines + halftone (10 steps) pattern (print rate 30%) are output in succession 50 sheets.
(8) Continuously output 150 black (BK) solid patterns (printing rate 80%).
(9) Black (BK) single-color character / line pattern (printing rate 7%) is output continuously 50 sheets.
<Evaluation criteria>
The image density unevenness is measured by measuring the relative reflection density at any nine locations in the black solid pattern page, the relative reflection density at all locations is 1.3 or more, and the difference between the maximum value and the minimum value is 0. “◯” when the value is less than or equal to 1, “Δ” when the minimum value of the relative reflection density is 1.2 or more and less than 1.3 and the difference between the maximum value and the minimum value is 0.1 or less. In the case where the minimum value of the relative reflection density is less than 1.2, or the difference between the maximum value and the minimum value exceeds 0.15, “x” is given.

<Experimental example 3>
In accordance with the configuration shown in FIG. 14, the developing devices 26 to 33 and 45 to 47 according to the present invention in which the stirring member is constituted by a rotating member shown in Table 4 below, and the developing devices 34 to 44 and 48 and 49 for comparison. Was made.

  Next, the amount of developer movement (using the second stirring member) was measured by the same method as described in Experimental Example 1. The results are shown in Table 4 below.

  However, the developer filling amount in the developing device, the rotation speed of the stirring member, and the like are different as shown in the table.

  Further, color image forming apparatuses 26 to 49 having the configuration shown in FIG. 1 equipped with the developing device are produced, and images are output based on the same image forming conditions as described in Experimental Example 1, and Evaluation was made according to the same criteria. The results are shown in Table 5.

  In Table 4, two types of rotation speeds of the first and second agitating members used in the comparative developing devices 38 to 44 are shown. 400 rpm is used for color image formation, and 650 rpm is used for monochrome image formation. Is the number of revolutions applied to. The results are shown in Tables 5 and 6.

<Experimental example 4>
Each of the developing devices 26 to 49 used in Experimental Example 3 has the same configuration as the developing devices 26 to 49 except that a recycled toner supply port is formed at a position 8 mm upstream of the toner supply port. Devices 26 to 49 (displayed with the same number for easy understanding of correspondence) were produced.

  According to the configuration shown in FIG. 12, image forming apparatuses 26 to 49 for forming a monochrome image having toner recycling means mounted thereon, each of the developing apparatuses 26 to 49 were manufactured.

  Next, images were output under the same image forming conditions as described in Experimental Example 2, and similar items were evaluated according to the same criteria. The results are shown in Table 6.

<Experimental example 5>
According to the configuration shown in FIG. 15, the developing devices 50 to 56 and 67 to 70 according to the present invention in which the stirring member is constituted by a rotating member shown in Table 7 below, and the developing devices 57 to 66 and 71 and 72 for comparison are used. Was made.

  Next, the amount of developer movement (using the second stirring member) was measured by the same method as described in Experimental Example 1. The results are shown in Table 7 below.

  However, the developer filling amount in the developing device, the rotation speed of the stirring member, and the like are different as shown in the table.

  In addition, a color image forming apparatus having the configuration shown in FIG. 1 mounted with the developing device is manufactured, and an image is output based on the same image forming conditions as described in Experimental Example 1, and the same items are similar. Evaluated by criteria. The results are shown in Table 8.

  In Table 7, two types of rotation speeds of the first and second stirring members of the comparative developing devices 60 to 63 are shown. 400 rpm is applied to color image formation, and 650 rpm is applied to monochrome image formation. The number of rotations. The results are shown in Tables 8 and 9.

<Experimental example 6>
Each of the developing devices 50 to 72 used in Experimental Example 5 has the same configuration as the developing devices 50 to 72 except that a recycled toner supply port is formed at a position 8 mm upstream of the toner supply port. Devices 50 to 72 (displayed with the same number for easy understanding of correspondence) were produced.

  In accordance with the configuration shown in FIG. 12, image forming apparatuses 50 to 72 for forming a monochrome image having toner recycling means mounted thereon, each of the developing apparatuses 50 to 72, were manufactured.

  Next, images were output under the same image forming conditions as described in Experimental Example 2, and similar items were evaluated according to the same criteria. The results are shown in Table 9.

  As is apparent from the above results, according to the image forming apparatus of the present invention, even when a developer in which a large amount of toner is consumed and toner replenishment including recycled toner is repeatedly used is used. Sufficient charge rising characteristics can be obtained.

  Further, it is possible to suppress the occurrence of image defects such as image fogging, character scattering, and image density unevenness, and to reduce the occurrence of in-machine contamination due to toner scattering, thereby forming a high quality image.

  On the other hand, in the comparative image forming apparatus, at least one problem of image fogging, character scattering, image density unevenness, and in-machine contamination has occurred, and it is difficult to reliably obtain a high-quality image. It is.

  In particular, in an image forming apparatus provided with a toner recycling unit, the rotational speed of the rotating member is increased to 650 rpm or more to obtain a sufficient developer moving speed, thereby suppressing the occurrence of uneven image density in the axial direction. In this case, the image output test had to be stopped due to a significant increase in the stirring torque, and an output image could not be obtained. As a result of investigating the cause, it was confirmed that the developer started to be fused to the shaft portion.

1 is a schematic diagram illustrating a first embodiment of an image forming apparatus according to the present invention. 1 is a plan view showing a first embodiment of a developing device according to the present invention. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is a schematic diagram which shows the 1st example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is the schematic which shows 2nd Embodiment of an image forming apparatus. FIG. 4 is a schematic diagram of a developing device for explaining a positional relationship between a toner supply port and a recycled toner supply port. It is the schematic which shows 2nd Embodiment of a developing device. It is the schematic which shows 3rd Embodiment of a developing device. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member. It is a schematic diagram which shows the other example of a stirring member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic document feeder 2 Image reading part 3 Image forming part 4 Belt unit 5 Paper feed part 6 Reverse discharge / re-feed part 8 Developing device 800 Developer carrier 803 1st stirring member 805 2nd stirring member 807 3rd Stirring member 809 Developer supply / recovery means 810 Housing 812 Cover 813 Toner supply port 850 Spiral rib 855, 856, 858 Plate-shaped rib

Claims (20)

A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The developer conveying capabilities of the first stirring member and the second stirring member are set to be substantially the same,
A third stirring member that does not have a developer conveying ability in the direction of the rotation axis is provided at a position opposite to the second stirring member and facing the first stirring member in the protruding region. ,
Setting the outer diameter of the third stirring member to be larger than the outer diameter of the first stirring member;
The first stirring member and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the upper side to the lower side,
The first agitating member and the third agitating member are opposed to each other, and the toner is supplied on the cover in a region corresponding to the upstream side in the developer conveying direction by the third agitating member. A toner supply port
A developing device. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The developer conveying capabilities of the first stirring member and the second stirring member are set to be substantially the same,
A third stirring member that does not have a developer conveying ability in the direction of the rotation axis is provided at a position opposite to the second stirring member and facing the first stirring member in the protruding region. ,
Setting the rotational speed of the third stirring member to be larger than the rotational speed of the first stirring member;
The first stirring member and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the upper side to the lower side,
The first agitating member and the third agitating member are opposed to each other, and the toner is supplied on the cover in a region corresponding to the upstream side in the developer conveying direction by the third agitating member. A toner supply port
A developing device. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The developer conveying capabilities of the first stirring member and the second stirring member are set to be substantially the same,
A third stirring member that does not have a developer conveying ability in the direction of the rotation axis is provided at a position opposite to the second stirring member and facing the first stirring member in the protruding region. ,
The peripheral speed of the third stirring member is set larger than the peripheral speed of the first stirring member,
The first stirring member and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the upper side to the lower side,
The first agitating member and the third agitating member are opposed to each other, and the toner is supplied on the cover in a region corresponding to the upstream side in the developer conveying direction by the third agitating member. A toner supply port
A developing device. 4. The development according to claim 1, wherein the third stirring member has a configuration in which a plurality of plate-like members are provided to be inclined in the same direction with respect to the rotation shaft. 5. apparatus. 5. The developing device according to claim 1, wherein the third stirring member has a configuration in which a plate-like rib is provided in a rotation axis direction. 6. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first agitating member is provided in the protruding region and has a developer conveying ability lower than that of the second agitating member, and a developer in a direction opposite to the developer conveying direction by the second agitating member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
A third agitating member that has substantially the same or lower developer conveying ability as the agitating portion 1A of the first agitating member and agitates while conveying the developer in a direction opposite to the conveying direction of the second agitating member; While arrange | positioning facing the stirring site | part 1A of the said 1st stirring member,
An outer diameter of the third stirring member is set larger than an outer diameter of the first stirring member;
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first agitating member is provided in the protruding region and has a developer conveying ability lower than that of the second agitating member, and a developer in a direction opposite to the developer conveying direction by the second agitating member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
A third agitating member that has substantially the same or lower developer conveying ability as the agitating portion 1A of the first agitating member and agitates while conveying the developer in a direction opposite to the conveying direction of the second agitating member; While arrange | positioning facing the stirring site | part 1A of the said 1st stirring member,
The rotation speed of the third stirring member is set larger than the rotation speed of the first stirring member, and
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first agitating member is provided in the protruding region and has a developer conveying ability lower than that of the second agitating member, and a developer in a direction opposite to the developer conveying direction by the second agitating member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
A third agitating member that has substantially the same or lower developer conveying ability as the agitating portion 1A of the first agitating member and agitates while conveying the developer in a direction opposite to the conveying direction of the second agitating member; While arrange | positioning facing the stirring site | part 1A of the said 1st stirring member,
The peripheral speed of the third stirring member is set larger than the peripheral speed of the first stirring member,
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device. The third stirring member includes a stirring portion including a plurality of plate-like members provided to be inclined in the first direction with respect to the rotation axis, and a plurality of plate-like members provided to be inclined in the second direction. The developing device according to claim 6, further comprising a stirring portion. 10. The developing device according to claim 6, wherein the third stirring member has a configuration in which a plate-like rib is provided in a rotation axis direction. 11. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first stirring member is provided in the protruding region and has a developer transport capability lower than that of the second stirring member, and the developer is in the same direction as the developer transport direction by the second stirring member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
The third stirring member has a higher developer transport capability than the second stirring member and stirs while transporting the developer in the direction opposite to the transport direction of the second stirring member. While being disposed facing the part 1A,
An outer diameter of the third stirring member is set larger than an outer diameter of the first stirring member;
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first stirring member is provided in the protruding region and has a developer transport capability lower than that of the second stirring member, and the developer is in the same direction as the developer transport direction by the second stirring member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
The third stirring member has a higher developer transport capability than the second stirring member and stirs while transporting the developer in the direction opposite to the transport direction of the second stirring member. While being disposed facing the part 1A,
The rotation speed of the third stirring member is set larger than the rotation speed of the first stirring member, and
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device. A developer carrying body for carrying and conveying a developer including toner and a carrier; and a side close to the developer carrying body and adjacent to the longitudinal direction of the developer carrying body, and A first stirring member that stirs while being conveyed in a direction, and a developer that is provided on the side far from the developer carrier and adjacent to the longitudinal direction of the first stirring member A second agitating member for agitating the developer while conveying the developer in a direction opposite to the conveying direction, and a housing for rotatably supporting the developer carrier, the first agitating member, and the second agitating member. And a developing device configured to circulate and convey the developer by the first stirring member and the second stirring member.
A configuration in which the first stirring member and the second stirring member are extended to a side corresponding to the upstream side in the developer transport direction by the second stirring member and protrude from an end portion of the developer carrier. And
The first stirring member is provided in the protruding region and has a developer transport capability lower than that of the second stirring member, and the developer is in the same direction as the developer transport direction by the second stirring member. And a stirring portion 1B that has substantially the same developer transport capability as the second stirring member and that transports the developer in a direction opposite to the developer transport direction by the second stirring member. In addition,
The third stirring member has a higher developer transport capability than the second stirring member and stirs while transporting the developer in the direction opposite to the transport direction of the second stirring member. While being disposed facing the part 1A,
The peripheral speed of the third stirring member is set larger than the peripheral speed of the first stirring member,
The stirring portion 1A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from the top to the bottom,
A toner supply port for supplying toner is provided on the cover in a region corresponding to the upstream side when the stirring portion 1A and the third stirring member are opposed to each other and viewed in the developer transport direction by the third stirring member. Provided,
A developing device. The stirring portion 1A is a stirring portion composed of a plurality of plate-like members provided to be inclined in the first direction with respect to the rotation axis and a plurality of plate-like members provided to be inclined in the second direction. The developing device according to claim 11, wherein the developing device includes a region. The developing device according to claim 11, wherein the stirring portion 1 </ b> A has a configuration in which a plate-like rib is provided in a rotation axis direction. The developer carrying member and the first stirring member are configured such that the peripheral surfaces rotate in opposite directions when viewed at the opposing proximity point. Development device. When the volume average particle diameter of the toner is Dt [μm] and the volume average particle diameter of the carrier is Dc [μm],
Dt = 3-5
Dc = 5 · Dt ~ 10 · Dt
The developing device according to any one of claims 1 to 16, wherein a developer containing a toner and a carrier is used. An image forming apparatus comprising: an image carrier; an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier; and a developing unit that develops the electrostatic latent image into a toner image.
While using the developing device of any one of Claim 1 thru | or 17 as said image development means,
The moving speed of the image carrier is V [mm / sec], the maximum adhesion amount per unit area of the toner image formed on the image carrier is M [mg / cm ² ], and the direction orthogonal to the moving direction of the image carrier The maximum width of the toner image is L [mm], the developer movement amount in the rotation axis direction of the developer carrier by the second stirring member is W [g / sec], and the rotation speed of the second stirring member is R [rpm]. When
W ≧ M ・ V ・ L / 1000
R ≦ 600
An image forming apparatus. An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, a developing unit that develops the electrostatic latent image into a toner image, and a toner on the image carrier A transfer unit that transfers the image to a transfer material or an intermediate transfer member; a cleaning unit that cleans the surface of the image carrier after the transfer; and a toner that is removed from the surface of the image carrier by cleaning is supplied to the developing unit. In an image forming apparatus having toner recycling means for recycling,
The developing device according to any one of claims 1 to 17 is used as the developing unit, and the portion on the cover of the developing device between the portion corresponding to the stirring portion 1A and the third stirring member. An image forming apparatus comprising a recycled toner supply port for supplying recycled toner at a position corresponding to the above. The image forming apparatus according to claim 19, wherein the recycled toner supply port is located upstream of the toner supply port as viewed in the developer transport direction by the first stirring member.

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