JP4292976B2 - Developing device and image forming apparatus - Google Patents

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 generally have a configuration in which toner recycling means is provided and toner is recycled from the viewpoint of environmental conservation or resource saving. Since the toner (recycled toner) collected from the image carrier once subjected to development is inferior to unused toner in charging characteristics, problems such as fogging and toner scattering due to insufficient toner charge amount. There is a problem of being invited.

In order to deal with such problems, many techniques for improving the stirring efficiency of the developer have been proposed in the past.For example, by providing a member that functions as an auxiliary stirring member, the stirring means has a high developer stirring ability. For example, Patent Document 1, Patent Document 2, and Patent Document 3 are used.
Japanese Unexamined Patent Publication No. 07-013420 JP 09-166918 A JP 09-288212 A

  However, any of the developing devices disclosed in the above-mentioned patent documents can improve the stirring efficiency of the developer, but on the other hand, since the circulating transport speed of the developer in the developing device is reduced, for example, As a developing device used for an image forming apparatus having a high process speed, there still seems to be room for improvement.

  In other words, when the circulating conveyance speed of the developer decreases, the toner concentration of the developer supplied to the development carrier becomes non-uniform in the rotation axis direction of the development carrier, and in particular, images with a high printing rate are continuously displayed. Image density unevenness is likely 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.

(1) A developer carrying member that carries and conveys a developer containing toner and a carrier, and a first stirring that is provided adjacent to the longitudinal direction of the developer carrying member and that stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
A third stirring member having a large outer diameter and a small length in the rotation axis direction with respect to the second stirring member, and having no ability to convey developer in the rotation axis direction; Provided facing the second stirring member in a region corresponding to the upstream side in the developer conveying direction by the second stirring member,
The second stirring member and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided between the second stirring member and the third stirring member on the cover in a region corresponding to the upstream side in the developer transport direction by the second stirring member. Provided
A developing device.

(2) A developer carrying body for carrying and transporting a developer containing toner and a carrier, and a first stirring which is provided adjacent to the longitudinal direction of the developer carrying body and stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Third agitation, which has a small length in the direction of the rotation axis with respect to the second agitation member and is driven at a high rotation speed but does not have the ability to convey the developer in the direction of the rotation axis. A member is provided opposite to the second stirring member in a region corresponding to the upstream side in the developer conveying direction by the second stirring member;
The second stirring member and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided between the second stirring member and the third stirring member on the cover in a region corresponding to the upstream side in the developer transport direction by the second stirring member. Provided
A developing device.

(3) A developer carrying body for carrying and conveying a developer containing toner and a carrier, and a first agitation provided adjacent to the longitudinal direction of the developer carrying body and carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Third agitation, which has a small length in the direction of the rotation axis with respect to the second agitation member and is driven at a high peripheral speed, but does not have the ability to convey the developer in the direction of the rotation axis. A member is provided opposite to the second stirring member corresponding to the upstream side of the second stirring member in the developer conveying direction;
The second stirring member and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided between the second stirring member and the third stirring member on the cover in a region corresponding to the upstream side in the developer transport direction by the second stirring member. Provided
A developing device.

  (4) The third agitation member includes a rotating shaft and a plurality of plate-like members provided to be inclined in the same direction with respect to the rotating shaft. The developing device according to any one of the above.

  (5) The third stirring member is configured integrally with the rotation shaft, the plurality of plate-like members provided to be inclined in the same direction with respect to the rotation shaft, and the rotation member. The developing device according to any one of (1) to (3), wherein the developing device includes a plate-like rib having a gap with respect to the shaft and extending in a rotation axis direction.

(6) A developer carrying body for carrying and transporting a developer containing toner and a carrier, and a first stirring which is provided adjacent to the longitudinal direction of the developer carrying body and stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
The second agitating member is lower in developer conveying capability in the rotation axis direction than the first agitating member, and is located on the downstream side in the developer conveying direction by the first agitating member; It has substantially the same developer conveying capability as the agitating member, and comprises a stirring portion 2B positioned on the upstream side of the developer conveying direction by the first agitating member,
The outer diameter of the second stirring member is larger than the outer diameter of the second stirring member, and the developer conveying ability is substantially the same as or lower than the stirring portion 2A, and the same as the conveying direction of the second stirring member. A third agitating member for agitating while conveying the developer in the direction is disposed opposite to the agitating portion 2A;
The stirring portion 2A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from above to below, and
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device.

(7) A developer carrying body for carrying and transporting a developer containing toner and a carrier, and a first stirring which is provided adjacent to the longitudinal direction of the developer carrying body and stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
The second agitating member is lower in developer conveying capability in the rotation axis direction than the first agitating member, and is located on the downstream side in the developer conveying direction by the first agitating member; It has substantially the same developer conveying capability as the agitating member, and comprises a stirring portion 2B positioned on the upstream side of the developer conveying direction by the first agitating member,
Conveying of the second agitating member having a developer conveying capacity substantially the same as or lower than that of the agitating portion 2A and driven at a higher rotational speed than the rotational speed of the second agitating member. A third agitating member that agitates the developer while conveying the developer in the same direction as the direction opposite to the agitating portion 2A;
The stirring portion 2A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from above to below, and
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device.

(8) A developer carrying member that carries and conveys a developer containing toner and a carrier, and a first stirring that is provided adjacent to the longitudinal direction of the developer carrying member and that stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
The second agitating member is lower in developer conveying capability in the rotation axis direction than the first agitating member, and is located on the downstream side in the developer conveying direction by the first agitating member; It has substantially the same developer conveying capability as the agitating member, and comprises a stirring portion 2B positioned on the upstream side of the developer conveying direction by the first agitating member,
It has substantially the same or lower developer conveying ability than the stirring portion 2A, has a peripheral speed higher than the peripheral speed of the second stirring member, and transports the second stirring member. A third agitating member that agitates the developer while conveying the developer in the same direction as the direction opposite to the agitating portion 2A;
The stirring portion 2A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from above to below, and
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device.

  (9) The third stirring member includes a rotation shaft, a plurality of plate-like members provided around the rotation shaft in a first direction with respect to the rotation shaft, and a second direction. The developing device according to any one of (6) to (8), further comprising: a plurality of plate-like members provided.

  (10) In any one of (6) to (8), the third stirring member has a plate-like rib extending in the longitudinal direction of the rotation shaft with a gap from the rotation shaft. The developing device described.

(11) A developer carrier that carries and conveys a developer containing toner and a carrier, and a first agitation that is provided adjacent to the longitudinal direction of the developer carrier and that agitates while conveying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Development of the first agitating member, wherein the second agitating member has a developer conveying ability lower than that of the first agitating member and is configured to convey the developer in the same direction as the conveying direction by the first agitating member. The first stirring member 2A positioned on the downstream side in the developer transport direction has substantially the same developer transport capability as the first stirring member, and is positioned upstream in the transport direction of the developer by the first stirring member. It comprises a stirring part 2B that transports the developer in the direction opposite to the transport direction of the stirring member,
A third agitating member that has a larger developer conveying capacity than the first agitating member and that agitates while conveying the developer in a direction opposite to the conveying direction of the first agitating member faces the agitating portion 2A. And the outer diameter of the third stirring member is larger than the outer diameter of the second stirring member,
The stirring part 2A and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device.

(12) A developer carrying member that carries and conveys a developer including toner and a carrier, and a first stirring that is provided adjacent to the longitudinal direction of the developer carrying member and that stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Development of the first agitating member, wherein the second agitating member has a developer conveying ability lower than that of the first agitating member and is configured to convey the developer in the same direction as the conveying direction by the first agitating member. The agitating part 2A positioned on the downstream side in the agent conveying direction and the developer conveying ability substantially the same as the first agitating member, and positioned on the upstream side in the developer conveying direction by the first agitating member, 1 a stirring portion 2B that transports the developer in the direction opposite to the developer transport direction by the stirring member,
The developer has a larger developer conveying capacity than the first agitating member and is driven at a higher rotational speed than the second agitating member so as to be opposite to the conveying direction of the first agitating member. A third agitating member for agitating while conveying is disposed opposite the agitating portion 2A, and
The stirring part 2A and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device.

(13) A developer carrying member that carries and conveys a developer including toner and a carrier, and a first stirring that is provided adjacent to the longitudinal direction of the developer carrying member and that stirs while carrying the developer in a predetermined direction. A member, a second stirring member provided adjacent to the longitudinal direction of the first stirring member, and stirring the developer while transporting the developer in a direction opposite to the developer transport direction by the first stirring member; and the developer In a developing device having a configuration including a carrier, a housing that rotatably and rotatably supports the first stirring member, and the second stirring member, and a cover provided on an upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Development of the first agitating member, wherein the second agitating member has a developer conveying ability lower than that of the first agitating member and is configured to convey the developer in the same direction as the conveying direction by the first agitating member. The first stirring member 2A positioned on the downstream side in the developer transport direction has substantially the same developer transport capability as the first stirring member, and is positioned upstream in the transport direction of the developer by the first stirring member. It comprises a stirring portion 2B that transports the developer in the direction opposite to the developer transport direction by the stirring member,
The developer has a peripheral speed higher than the peripheral speed of the second agitating member, has a larger developer conveying capability than the first agitating member, and has developer in a direction opposite to the conveying direction of the first agitating member. A third stirring member that is stirred while being conveyed is disposed opposite to the stirring portion 2A;
The stirring part 2A and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device.

  (14) The stirring portion 2A is provided with a rotating shaft, a plurality of plate-like members provided around the rotating shaft and inclined in the first direction with respect to the rotating shaft, and inclined in the second direction. The developing device according to any one of (11) to (13), wherein the developing device includes a plurality of plate-like members.

  (15) Any one of the above (11) to (13), wherein the stirring portion 2A includes a plate-like rib extending in the longitudinal direction of the rotation shaft with a gap between the rotation shaft and the rotation shaft. The developing device according to 1.

  (16) The developer carrying member and the first agitating member move in opposite directions when viewed from their proximity points, as described in any one of (1) to (15) above Development device.

(17) The developer conveyed by the first stirring member is supplied to the developer carrying member between the developer carrying member and the first stirring member, and the first stirring member is supplied from the developer carrying member. Provided with a rotatable developer supply / recovery member for collecting the developer, and
The developer supply / recovery member and the developer carrier are moved in opposite directions when viewed from their proximity points, according to any one of (1) to (15), Development device.

(18) 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 (1) to (17), wherein a developer containing the toner and carrier is used.

(19) 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. In
While using the developing device according to any one of (1) to (18) as the developing 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 first stirring member is W [g / sec], and the rotation speed of the first stirring member is R [rpm]. When
W ≧ M ・ V ・ L / 1000
R ≦ 600
An image forming apparatus.

(20) 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 the image carrier Transfer means for transferring the toner image on the transfer material or intermediate transfer body, cleaning means for cleaning the surface of the image carrier after transfer, and toner removed from the surface of the image carrier by the cleaning means as the development means In an image forming apparatus having a toner recycling means for supplying and recycling to
The developing device according to any one of (1) to (18) is used as the developing means, and the developing device is on the cover of the developing device and corresponds between the stirring portion 2A and the third stirring member. An image forming apparatus comprising a recycled toner supply port for supplying recycled toner at a position where the toner is supplied.

  (21) The image forming apparatus according to (20), wherein the recycled toner supply port is upstream of the toner supply port.

  According to the developing device of the present invention, for example, the developer is circulated in the direction of the rotation axis of the developer carrier while stirring the developer with two stirring members (first stirring member, second stirring member). This is a configuration that balances the conveyance speed or conveyance amount, stirs the developer in the circumferential direction without substantially conveying the developer in the rotation axis direction by the third agitating member, and raises the charge of the toner in the developer. In addition, sufficient stirring time can be ensured without lowering the developer conveying speed.

  Then, since the toner in the developer is supplied to the developer carrier in a state where the toner has a desired charge amount, it is possible to suppress the occurrence of fogging and toner scattering due to poor charging of the toner. Even so, high image quality can be maintained.

  Further, the selection of the transport direction and transport capability of the developer on one end side of the second stirring member and the third stirring member having the transport capability of transporting the developer in the rotation axis direction are the same as described above. In addition, for example, the mixing and stirring of the replenishing toner and the developer can be efficiently performed while maintaining the balance between the developer conveyance speed and the conveyance amount.

  In addition, a third stirring member is provided opposite to a part of the second stirring member in the longitudinal direction, and both the stirring members are viewed at their opposing proximity points. Since it is configured to move and to replenish the toner from above corresponding to the opposite part, the sinking of the replenished toner into the developer can be accelerated.

  In other words, since uniform replenishment of the replenishment toner in the developer can be performed quickly, the desired charge amount can be easily imparted to the toner via the circulation conveyance.

  Further, since the axial length of the third stirring member may be shorter than the axial length of the second stirring member, for example, the developing device can be kept small for the effect to be achieved. Furthermore, since the container for storing the replenishing toner provided on the image forming apparatus main body side and the lower space in which 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 of the present invention, 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 operating 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 occurrence of toner scattering, fogging, image density unevenness and the like can be suppressed as much as possible, and high-quality images 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 includes an automatic document feeder 1 at the top of the apparatus main body, and includes an image reading unit 2, an image forming unit 3, a belt setting unit for the belt unit 4, and a paper feeding unit. 5, a fixing device T, a reverse discharge / refeed unit 6, and an ADU 7 as reverse transfer 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 forms four image forming units (hereinafter referred to as image forming units) of yellow (Y), magenta (M), cyan (C), and black (BK) that form a toner image corresponding to a color separation image. ) 30.

  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. A scorotron charger 320, an exposure optical system 330 as image writing means, a developing device 8 for developing an electrostatic latent image, a transfer means 340, and a blade for cleaning the surface of the photosensitive drum 310 after transfer (cleaning) The main component is a cleaning device 350 including the means.

  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. A developer carrying member (developing sleeve) having a rotatable and non-magnetic cylindrical shape incorporating a magnet in which the magnets are arranged is described in detail later.

  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 the image area where the toner image (Y) is present, 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 device 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. The color toner image carried (formed) on the intermediate transfer belt 401 is transferred onto the paper P during this time while being pressed and nipped together with the intermediate transfer belt by 510.

  Note that an appropriate transfer bias voltage is applied between the transfer roller 510 and the backup roller 410 at the time of 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 this specification, the left-right direction in FIG. 2 is referred to as “front-rear direction”, and the up-down direction in FIG. 2 is referred to as “axial direction”, “rotational axis direction”, or “longitudinal direction”. Further, the vertical direction in FIGS. 3 and 4 is expressed as “vertical direction”.

  The developing device 8 includes a developer carrying member (developing sleeve) 800, a first stirring member 803 that is rotatably disposed at a position (front side) adjacent to the longitudinal direction of the developer carrying member 800, and the image carrying member. A second agitating member 805 located at a position farther from the body (rear side) and adjacent to the longitudinal direction of the first agitating member 803 and rotatably disposed; and the longitudinal direction of the second agitating member A rotatable third stirring member provided at a position on the rear side adjacent to a predetermined region (a downstream position in the developer conveying direction by the first stirring member and corresponding to a protruding region 802 described later) 807, a housing 810 that supports these members in an axial direction while keeping them parallel to each other in the axial direction, and an openable / closable cover 812 that covers the top of the housing.

  Further, the first stirring member 803 and the second stirring member 805 are configured to be longer than the length of the developer carrier 800.

  Then, by positioning one end position of both agitating members in substantially the same plane as the end position of the developer carrier, the housing 810 and the end of the developer carrier 800 on the other side. Is also protruding.

  In other words, as shown by the arrow in FIG. 2, the first agitating member 803 extends and protrudes downstream in the developer conveyance direction. Reference numeral 802 indicates a protruding region.

  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.

  Reference numeral 808 denotes a partition wall formed by raising from the bottom of the housing 810, which is located between the first stirring member 803 and the second stirring member 805, and the portions at both ends thereof are missing and a developer delivery portion. 820 and 821 are formed (which can also be referred to as a developer circulation passage).

  Further, as shown in FIG. 3, the developer carrier 800 and the first stirring member 803 are stored in a developer storage stirring portion (hereinafter referred to as a first storage stirring portion) 815 formed in the housing 810. In addition, the second stirring member 805 and the third stirring member 807 are another storage stirring unit (hereinafter referred to as a second storage stirring unit) 816 formed adjacent to the first storage stirring unit 815. Is housed in.

  The first storage agitation unit 815 and the second storage agitation unit 816 store an appropriate amount of a two-component developer including a magnetic carrier and a nonmagnetic toner.

  The rotating member such as the stirring member receives power from a drive system provided on the image forming apparatus main body side, and is configured to rotate in the direction of the arrow through a gear or the like. However, a known technology is used for the power transmission mechanism. it can.

  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 the first stirring member. Reference numeral 803 denotes a counterclockwise direction, the second stirring member 805 rotates clockwise, and the third stirring member 807 rotates counterclockwise.

  The first agitating member 803 and the second agitating member 805 are preferably constituted by a rotating member having a high developer conveying capability in the rotation axis direction from the viewpoint of preventing occurrence of toner density unevenness in the rotation axis direction.

For example, as schematically shown in FIG. 5, the rotary member is formed of a spiral rib (screw) formed with a predetermined orientation in the axial direction and a predetermined pitch p over the entire circumference of the outer peripheral surface of the shaft. be able to.
In the case of lowering the developer transport capability, the developer transport capability in the direction of the rotation axis can be lowered by setting the pitch p1 smaller than the pitch p.

  In order to circulate the developer, the end portions of the first and second stirring members on the downstream side in the developer transport direction (portions corresponding to the transfer portions 820 and 821) have predetermined lengths and widths. The blade member is formed so as to protrude from the rotating shaft to form a paddle, but this configuration is well known, and its structure is not directly related to the invention, so it is omitted in the figure. The number of blade members in the circumferential direction of the rotating shaft can be determined as appropriate.

  In the figure, 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 transport direction of the developer when the first stirring member 803 and the second stirring member 805 are rotated in the above-described direction, and the length of the arrow indicates the developer transport capability ( Developer transport speed, developer transport amount, etc.).

  The developer transport direction will be described. The rotation of the first stirring member 803 transports the developer in the first direction (in the drawing, the rotation axis direction from the upper side to the lower side), and the second stirring member 805 is rotated. The rotation conveys the developer in the direction opposite to the conveyance direction by the first stirring member 803 (in the drawing, the rotation axis direction from the lower side to the upper side).

  The rotation of the third stirring member 807 has the ability to stir the developer in the circumferential direction of the rotating shaft, but the ability to transport the developer with respect to the rotating shaft direction is substantially zero.

  For example, as shown in FIG. 6, the third stirring member 807 is configured as a rotating member in which a plurality of plate-like members 851 are arranged with a predetermined angle at equal intervals with respect to the rotation axis J. can do.

  In other words, the plate-like member 851 is skewed by the rotation axis J. The shape of the plate-like member is an elliptical shape in the present embodiment, but may be a shape other than an elliptical shape as long as the intended purpose can be achieved.

  Regarding the developer conveying ability, the first stirring member 803 and the second stirring member 805 have substantially the same conveying ability, and the third stirring member 807 is substantially zero.

  According to the developing device having the above-described configuration, the developer in the first storage stirring unit 815 is conveyed in the axial direction indicated by the arrow while being stirred in the circumferential direction of the rotation axis J by the rotation of the first stirring member 803. In addition, the second storage and agitation unit 816 is sent via the transfer unit 821.

  The developer in the second storage agitation unit 816 is conveyed in the direction opposite to the conveyance direction by the first agitation member while being agitated in the circumferential direction of the rotation axis J as the second agitation member 805 rotates, and the partition plate It is sent to the first storage and stirring unit 815 via a transfer unit 820 formed at the end of 808, and is circulated and transported in a state of receiving the action of the first stirring member 803 again.

  Further, the developer that receives the action of the third stirring member 807 is stirred in the circumferential direction of the rotation axis J to promote the rising of the charge, and is sequentially subjected to the action of the second stirring member 805 described above.

  Note that the developer containing toner that has reached a predetermined charge amount due to the mixing / stirring action during the circulation and conveyance is transported by the first agitating member 803 on the peripheral surface of the developer carrier 800 and the shaft. The toner in the developer is consumed for the visualization.

  The developer on the developer carrier 800 is automatically removed from the developer carrier by the action of a repulsive magnetic field after passing through the development region.

  At this time, since the first stirring member 803 and the developer carrier 800 are rotated in the opposite direction (axis) at the closest point, the removed toner is not immediately supplied to the developer carrier 800. The first agitating member 803 receives the stirring and conveying action, is taken into the circulation channel, and obtains the desired charge amount while being conveyed through the circulation and conveyance route, and is used for the development processing. Become.

  In other words, the developer supplied to the developer carrier 800 by the first agitating member 803 and the first agitating member 803 are set by rotating the developer carrier 800 and the first agitating member 803 as described above. Therefore, it is possible to reliably replace the developer collected in this way, and therefore, the toner density of the developer in the axial direction of the developer carrier 800 can be kept uniform, thereby reducing the occurrence of image density unevenness. it can.

  The developer after the development processing is detected by the toner concentration detection sensor, and based on the detected value, unused toner (hereinafter referred to as new toner) passes through the toner supply port 813 from a toner supply mechanism (not shown). Supplied through.

  The toner supply port 813 has a substantially intermediate position where the second stirring member 805 and the third stirring member 807 face each other (as shown in the side sectional view of FIG. 4, the second stirring member 805 and the third stirring member 807). Is provided on the cover 812 corresponding to an appropriate position on the upstream side in the developer transport direction by the second stirring member.

  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 is set to the upstream position as described above, which is intended to achieve effective mixing and stirring even when the axial length of the third stirring member 807 is short.

  The supplied toner is efficiently stirred with the developer by the rotation of the second stirring member 805 and the third stirring member 807.

  That is, the second agitating member 805 and the third agitating member 807 are rotated in such a manner that the peripheral surfaces move in the forward direction from the upper side toward the lower side (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, and the toner can be rapidly and uniformly dispersed in the developer.

  As described above, by making the developer conveying capabilities of the first agitating member 803 and the second agitating member 805 substantially the same, it is possible to suppress the occurrence of developer stagnation on the circulation conveying path and to smoothly circulate the developer. Can be done.

  Further, the operation of imparting a predetermined charge amount to the toner can be promoted through sufficient mixing and stirring operation by the third stirring member 807 without reducing the developer conveyance speed.

  Furthermore, since sufficient stirring can be performed in the circumferential direction of the stirring member, for example, a developer having a uniform toner concentration in the axial direction of the second stirring member can be easily obtained in a short time. .

  As is clear from the above, the first stirring member 803 in the present embodiment has a function of supplying the developer to the developer carrier 800 and the developer after development removed from the developer carrier 800. It can also be said that the developer supply and recovery member has a function of recovering the toner.

  The toner that is a component constituting the developer preferably has a volume average particle diameter of 3 to 5 μm. Such a small particle diameter toner is a toner having high resolution and excellent fine line reproducibility. An image can be formed, and a stable toner image without image density unevenness can be formed in a solid portion (solid image portion) or a halftone 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 in the rotational axis direction of the developer carrier by the first stirring member [g / Sec] and R indicate the rotation speed [rpm] of the first stirring member.

  When the developer movement amount (developer transport amount) W in the rotation axis direction by the first agitating member 803 is excessively small, the developer in the developer supply region downstream of the first agitating member 803 in the developer transport direction. Therefore, it becomes difficult to supply a sufficient amount of toner to the developing area, and image density unevenness is likely to occur.

  In addition, when the rotation speed of the first stirring member 803 is excessive, the developer is likely to be deteriorated by heat generated in the shaft portion of the first stirring member 803, and a high-quality image is formed over a long period of time. Difficult to do.

  In other words, by performing the development process in a state where the specific conditions (a) and (b) described above are satisfied, the developer can be supplied to the development area in the axial direction without toner density unevenness. Therefore, an image having a uniform image density without image density unevenness can be obtained.

  In addition, by setting the number of rotations of the first stirring member to 600 rpm or less, it is possible to prevent the developer from being deteriorated by heat generated when the first stirring member is rotated at a high speed.

  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.

  Next, a developing apparatus according to the second embodiment that can be used in the image forming apparatus in the same manner as the developing apparatus according to the first embodiment will be described with reference to FIG.

  In other words, the second agitating member in the first embodiment has substantially the same developer transporting capability over the entire length of the agitating portion in the rotation axis direction, but the second agitating member in the second embodiment. In this case, the developer carrying capacity in the area corresponding to the predetermined area on the downstream side of the first stirring member (corresponding to the protruding area 802) is made smaller than the developer carrying capacity in the other areas, and as described below. The third stirring member is configured to have a transport capability for transporting the developer in the same direction as the second stirring member.

  Other configurations other than the above-described configurations related to the second and third stirring members, such as the rotation direction of each stirring member and the relative positional relationship including the toner supply port, are described in the first embodiment. Therefore, the same members as those shown in the first embodiment are denoted by the same reference numerals, and redundant description is avoided as much as possible.

  As described above, in the present embodiment, the stirring portion of the second stirring member 805 corresponding to the predetermined region on the downstream side of the first stirring member 803 (this portion is also a region corresponding to the protruding region indicated by reference numeral 802). The developer carrying ability (developer carrying amount) in an area outside the developer carrying member) is lower than the developer carrying ability of the first stirring member 803. It is configured.

  In other words, the second stirring member 805 in the present embodiment is provided with a developer transport that is lower than the developer transport capability of the first stirring member 803 provided on the upstream side in the developer transport direction by the second stirring member. A part having an ability (hereinafter, this part is referred to as a stirring part 2A) and a part (hereinafter, this part) having substantially the same developer conveying ability as that of the first stirring member provided integrally on the downstream side of the stirring part 2A. The portion is referred to as a stirring portion 2B).

  In the developing device configured as described above, the first agitating member 803 is sent to the second storage agitating unit 816 via the delivery unit 821, and the developer transport capability by the agitating part 2A cannot be covered. Is balanced by the developer carrying capacity of the third stirring member 807, thereby balancing the developer carrying amount.

  For example, this can be dealt with by setting the developer conveying ability of the stirring portion 2A and the third stirring member 807 to be about ½ of the developer conveying ability of the first stirring member 803, respectively.

  Of course, the developer conveying ability of the third agitating member 807 can be made lower than that of the agitating portion 2A, and the developer conveying ability is substantially the same as that of the first agitating member as a total, It can be appropriately selected and determined as long as there is no problem such as clogging or retention of the agent.

  The agitating portion 2A and the third agitating member 807 are substantially at an intermediate position (see FIG. 4), and in the developer conveying direction (here, the developer is conveyed by the second agitating member and the third agitating member). A toner supply port 813 through which new toner is supplied from a toner supply mechanism (not shown) is provided on the cover 812 corresponding to an appropriate position on the upstream side as viewed in the same direction.

  The supplied toner is efficiently stirred with the developer by the rotation of the stirring portion 2A and the third stirring member 807.

  The developing device having the above configuration has the effects of the developing device of the first embodiment.

  FIG. 8 is a diagram showing a third embodiment of a developing device applicable to the image forming apparatus.

  In the following drawings, the same members (means) as the above-described members (means) or members having the same function are denoted by the same reference numerals.

  The developing device in the present embodiment has the same configuration as the developing device in the second embodiment. The difference is that the stirring portion 2A of the second stirring member 805 is the developer by the first stirring member 803. That is, the developer is transported in the same direction as the transport direction, and the third stirring member 807 is configured to have a high developer transport capability.

  The rotation of the third agitation member 807 conveys the developer in the direction opposite to the conveyance direction of the first agitation member 803 and the conveyance direction by the agitation site 2A of the second agitation member.

  Note that the developer carrying capacity will be described. Based on the carrying ability of the first stirring member 803, the stirring portion 2A of the second stirring member 805 has a lower carrying ability than the first stirring member, and the stirring portion. 2B has substantially the same conveying ability as the first stirring member.

  In addition, the third stirring member 807 has a higher transfer capability than the transfer capability of the first stirring member 803.

  According to the developing device having the above configuration, the developer in the first storage stirring unit 815 is conveyed in the axial direction indicated by the arrow while being stirred in the circumferential direction by the rotation of the first stirring member 803, and It is sent to the second storage agitation unit 816 via the delivery unit 821.

  The developer in the second storage agitating unit 816 is conveyed in the same direction as the conveying direction by the first agitating member in the region of the agitating part 2A while being agitated in the circumferential direction as the second agitating member 805 rotates. Then, in the region of the stirring portion 2B, it is continuously conveyed in the direction opposite to the conveying direction by the first agitating member (from the lower side to the upper side in the drawing), and sent to the first storage agitating unit 815 via the delivery unit 820. Then, the first agitating member 803 is circulated and transported again in a state of receiving the action.

  During the image formation, the developer containing toner that has reached the predetermined charge amount by the mixing / stirring action during the circulation and conveyance is conveyed by the first agitating member 803 and the peripheral surface of the developer carrier 800. Above, supplied in the axial direction and subjected to development processing, the toner in the developer is consumed for visualization, or after the developer on the developer carrier 800 passes through the development area, For example, after being automatically removed from the developer carrying member by the action of the repulsive magnetic field and dropped into the first storage stirring unit 815, the circulation channel described above receives the stirring and conveying action of the first stirring member 803. In this case, the desired charge amount is obtained again while being transported through the circulation transport path and used for development processing, or new toner is appropriately supplied via the toner supply port 813. This is the case in the two embodiments described above. Using a developing apparatus is similar to the case of forming an image.

  Needless to say, the developing device according to the third embodiment has the same effect as the other developing devices described above.

  As the stirring member, in addition to the configuration shown in FIG. 5, a rotating member having the following configuration can be used as appropriate.

  The agitation member shown in FIG. 9 has 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. ing.

  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 stirrer shown in FIGS. 10 to 12 has the same basic configuration as the stirrer shown in FIG. 5, but further increases the developer stirring ability, and causes toner density unevenness in the axial direction. It has sufficient developer transport capability that is required to prevent this.

  The stirring member shown in FIG. 10 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 rod-like or plate-like rib (vertical blade) 855 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 (linear shape) 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. 11 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 row of the notches 857 has a configuration of two rows that are 180 degrees out of phase 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.

  The agitating member shown in FIG. 12 is rotated through the spiral rib 850 formed over the entire outer peripheral surface of the rotating shaft J and 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.

  According to the developing device provided with these agitating members, basically, a sufficiently large developer conveying speed can be obtained, and the toner concentration with respect to the axial direction of the developer supplied to the developer carrying member. The occurrence of unevenness can be prevented, and sufficient charge rising characteristics of the toner can be reliably obtained, so that problems such as toner scattering and fogging due to poor charging can be reduced and suppressed.

  FIG. 13 shows a configuration example that can be used as a third stirring member that does not have a conveyance capability in the direction of the rotation axis, or a developer supply and recovery member that will be described later.

  The 3rd stirring member which consists of a rotation member shown in the figure is on the outer peripheral surface of the rotating shaft J, and has the structure which formed the plate-shaped rib 852 linearly along the axial direction.

  The third agitating member of the illustrated configuration has a cross paddle shape in which the rib 852 is provided at four locations equally dividing the circumferential direction of the rotation axis J, as long as the intended purpose can be achieved. Well, the design freedom is wide.

  Note that the third stirring member that has substantially no conveying force in the direction of the rotation axis is more preferable as the developer stirring ability is higher from the viewpoint of obtaining sufficient toner charge rising characteristics. FIG. 15 shows a more preferable configuration example.

  The stirring member shown in FIG. 14 has four plate-like members that support the plate-like member through engagement between a plate-like member, for example, a plurality of plate-like members 851 made of an ellipse and the peripheral edge of the plate-like member 851. A rib 858, disc-shaped flanges 853 provided at both ends so as to engage and hold the end portions of the plate-like ribs 858, and a rotation shaft extending outward from the center of the flange 853 (Not shown) is the main element.

  The plate-like members 851 have an inclination of a predetermined angle α with respect to the rotation center (axis), and are arranged in the axial direction with a predetermined pitch p.

  The external parts after assembling the plate-like member 851, the flange 853, and the rib 858 have substantially the same surface without unevenness.

  The stirring member configured in this manner stirs the developer in the circumferential direction by the plate-like member 851 and rotates the developer by the plate-like rib 858 when rotating around the rotation axis.

  The stirring members shown in FIG. 15 are arranged at equal intervals in the circumferential direction of the flange 853 and two disk-like flanges 853 that each engage with the end of the rotation shaft J and hold the rotation shaft. The main elements are four plate-like ribs 858 and a plurality of plate-like members 851 supported by the ribs 858 in a state where the rotation axis J penetrates along a plane perpendicular to the rotation axis J.

  The rib 858 is made of a plate extending in the direction of the rotation axis, and the plate-like member 851 is a disc having a notch portion 854 having a predetermined size except for a predetermined region at the center portion that fits with the rotation shaft. It is made up of.

  The plate-like members 851 are positioned so as to alternately occupy opposite positions with respect to the rotation axis J, and are arranged in the axial direction with a predetermined pitch p.

  The size of the area of the plate-like member in contact with the developer, the pitch p, the size of the area of the plate-like rib 858 in contact with the developer, etc. in FIG. 14 and FIG. Can do.

  In addition, according to the developing device including the third stirring member having such a configuration, the above-described operations and effects can be obtained more reliably, and further reduction of toner scattering and fogging due to toner charging failure can be expected. In addition, the occurrence of uneven image density due to non-uniformity of the toner density in the axial direction of the developer supplied to the developer carrier can be similarly reduced.

  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.

  In the above description, the main components of the developing device are the developer carrier, the first stirring member, the second stirring member, and the third stirring member. However, the schematic diagram of FIG. 16 and the A- As in the fourth embodiment of the developing device shown in FIG. 17 showing the A section, a rotatable developer supply / recovery member 809 is provided between the developer carrier 800 and the first stirring member 803. be able to.

  In the above configuration, the rotation direction of the developer carrier 800 is counterclockwise, the rotation direction of the developer supply / recovery member 809 is counterclockwise, and the rotation directions of the first stirring member 803 and the second stirring member 805 are clockwise. Yes, the rotation direction of the third stirring member (not shown) is the same as the rotation direction in the first embodiment, and the peripheral surfaces of the third stirring member (not shown) are directed from the top to the bottom at a point close to the second stirring member 805. The shaft is rotated in the direction of movement.

  The above configuration scoops up the developer that is circulated and transported containing the toner having a desired charge amount from the first agitating member 803 with the developer supply / recovery member 809, and the shaft on the developer carrier 800. As well as supplying the developer in the direction, the operation of guiding the developer removed from the developer carrier 800 to the circulation conveyance path via the first stirring member 803 can be smoothly performed.

  The developer supply / recovery member 809 can basically have the same configuration as the stirring member shown in FIG. 13, but may have the configuration shown in FIG. 6, the configuration shown in FIGS. The configuration and the like are not limited.

  In FIG. 16, the reason why the hollow arrow indicating the developer conveyance direction or the conveyance capability is not included is that the present invention can be applied to any of the first to third embodiments.

  Furthermore, in the developing device according to the present invention, for example, when the outer diameter, the rotation speed, and the peripheral speed of the first stirring member and the second stirring member stirring portion 2A are used as a reference, the outer diameter and the rotation speed of the third stirring member. The developer agitating performance is improved by setting the peripheral speed to be large or high.

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

  The image forming apparatus shown in FIG. 18 has toner recycling means (toner recycling apparatus) that collects the toner removed from the photosensitive drum after transfer, and finally returns it to the developing device for reuse.

  The image forming apparatus shown in FIG. 18 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, and a fixing device. However, these can be understood from the drawings and explanations relating to the first embodiment, and the developing device 8 has the same configuration as that of the fourth embodiment (FIG. 16). 1 schematically shows a full rotation member (stirring member) including a developer supply and recovery member.

  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 pole and a separation pole are provided between the developing device 8 and the cleaning device 350 in the rotational direction of the photosensitive drum 310.

  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 recovery member 353 made of a screw that conveys toner (also referred to as toner) in the axial direction of the photosensitive drum 310 and in a predetermined direction (front side in the figure) 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 transport unit 901 is built in a cylindrical outer frame 903 (shown by a two-dot chain line for the sake of convenience), and a recycle 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 at a substantially intermediate position (see FIG. 4 for the intermediate position) where the second stirring member 805 and the third stirring member 807 are opposed to each other. When it is assumed that the developer transport direction is from the lower side to the upper side in FIG. 16, the upstream side as viewed in the developer transport direction of the second stirring member and the upstream side from the toner supply port 813 described above. Are provided on the cover 812 corresponding to appropriate positions.

  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 can be understood from FIG.

  The distance between the two is not particularly limited, but 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 813.

  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, it is possible to quickly sink the recycle toner, which has poor fluidity and low chargeability compared to the new toner, into the developer, and the mixing and stirring time. Therefore, it is possible to obtain a desired charge even for recycled toner, to suppress the occurrence of fog and toner scattering due to poor charging of the toner, and to suppress the occurrence of image density unevenness in image formation. Can do.

  Specifically, in the process in which the developer is transported in the axial direction by the second stirring member 805, a sufficient mixing and stirring time is secured in the second storage stirring unit 816 without reducing the transport speed of the developer, The developer charged so that the toner has a desired charge can be supplied from the first stirring member 803 to the developer carrier 800 with a uniform toner concentration in the axial direction by the developer supply / recovery member 809.

  Further, since the recycled toner is introduced from the recycled toner supply port 825 provided on the upstream side of the toner supply port 813 in the developer transport direction by the second agitating member 805, the low-charged recycled toner is developed first. After being dispersed in the agent, the new toner can be dispersed, and a long mixing and stirring time for the recycled toner can be secured.

  Accordingly, 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 toner supply including recycled toner are repeatedly performed by continuously outputting images 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.

  Next, experimental examples conducted for confirming the effects of the present invention will be described.

[Production of rotating member]
As described below, rotating members used as the first stirring member, the second stirring member, the third stirring member, and the developer supply and recovery member were produced.
(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 radially outward to form a paddle shape, and further, a disk-shaped flange member having an outer dimension of 24 mm is provided at both ends of the rotating member. Rotating member.

  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 QQ)
As shown in FIG. 13, plate-like ribs (flat blade members) extending radially outward and in the longitudinal direction of the shaft are provided from four equally divided locations in the circumferential direction of the shaft, thereby forming a cross paddle. Rotating member.

  The specifications of the rotating member QQ are as follows.

Maximum outer diameter (d): 24 mm, rotation shaft direction length excluding shaft part: 360 mm, shaft member outer diameter: 6 mm, plate member thickness: 1 mm, radial length (h): 9 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 D)
In the rotating member AA, the length in the axial direction excluding the shaft portion is 110 mm, the spiral rib is formed in a right-handed manner, and the pitch (p) of the spiral rib is 40 mm. A rotating member having the same configuration as the above.
(Rotating member D30)
A rotating member having the same configuration as that of the rotating member D except that the maximum outer diameter (d) of the rotating member D is 30 mm.
(Rotating member P)
A spiral rib (screw) as shown in FIG. 12 is formed on the outer peripheral surface of the shaft member in a right-handed manner, and a plate-like rib extending in the axial direction without a break on the outer peripheral edge of the spiral rib. A rotating member having a provided structure.

  The specifications of the rotating member P are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 110 mm, outer diameter of the shaft member: 6 mm, pitch of the spiral rib (p): 30 mm, thickness of the spiral rib: 1 mm, Radial length of plate-like rib (t): 3 mm, plate-like rib thickness: 1 mm, plate-like rib attachment location: four locations in the circumferential direction (equally spaced)
(Rotating member P30)
The rotating member P has the same configuration as the rotating member P except that the maximum outer diameter (d) is 30 mm.
(Rotating member S)
As shown in FIG. 6, it has a configuration in which a plurality of plate-like members having an elliptical shape in the axial direction are arranged, and a configuration in which disc-shaped flange members having an outer dimension of 24 mm are provided at both ends of the rotating member. Rotating member.

  The specifications of the rotating member S are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 110 mm, outer diameter of the shaft member: 6 mm, thickness of the plate member: 1 mm, attachment angle of 45 ° with respect to the shaft of the plate member, plate shape Arrangement pitch of members: 25mm
(Rotating member S30)
The rotating member S has the same configuration as the rotating member S except that the maximum outer diameter (d) is 30 mm.
(Rotating member T)
As shown in FIG. 14, a rotating member having a configuration in which a plurality of elliptical plate-like members are arranged in the axial direction, and plate-like ribs extending in the axial direction are provided at regular intervals in the circumferential direction. .

  The specifications of the rotating member T are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 110 mm, outer diameter of the shaft member: 6 mm, thickness of the plate member: 1 mm, attachment angle 45 ° with respect to the shaft of the plate member, plate shape Arrangement pitch of members: 25 mm, radial length of plate-like rib (t): 3 mm, thickness of plate-like rib: 1 mm, attachment location of plate-like rib: 4 (equally spaced in the circumferential direction)
(Rotating member U)
As shown in FIG. 9, 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. A rotating member having a portion.

  The specifications of the rotating member U are as follows.

Maximum outer diameter (d): 24 mm, length in the rotation axis direction excluding the shaft portion: 110 mm, shaft member outer diameter: 6 mm, plate member thickness: 1 mm, shaft of the plate member constituting the first stirring unit 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 KA)
As the stirring part 2A, a spiral rib (left-handed) including a plate-like rib extending in the axial direction shown in FIG. 12 as a stirring part, and as a stirring part 2B, a spiral rib (left-handed) shown in FIG. 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 having an outer dimension of 24 mm 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 2A is 110 mm, stirring portion 2B is 330 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, 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 2A is wound clockwise and the pitch of the spiral rib of the portion is 20 mm.
(Rotating member UA)
The rotating part 2A has the structure of the rotating member U, the stirring part 2B has the structure of the rotating member AA, and on the outer peripheral surface of the shaft over a length of 30 mm on the downstream side in the overall conveyance direction of the developer. A rotating member having a configuration in which four flat blade members are provided so as to extend radially outward to form a paddle shape, and disk-shaped flange members having an outer dimension of 24 mm are provided at both ends of the rotating member. .

<Experimental example 1>
[Create developer]
For example, in the developing device having the configuration shown in FIGS. 2, 7, and 8, the first stirring member, the second stirring member, and the third stirring member are constituted by rotating members shown in Table 1 below. Developing devices 1 to 10 were produced.

  Further, a comparative developing device 11 having a configuration in which the third stirring member was removed from the configuration as described above was produced.

  FIG. 19 shows a comparative developing device that does not have a third stirring member.

  Further, as shown in FIG. 16, the developing device is provided with a developer supply / recovery member in addition to the first to third stirring members, and each rotating member is selected according to the combination shown in Table 1 below. The developing devices 12 to 21 according to the present invention constituted by the rotating members and the comparative developing device 22 from which the third stirring member was removed were produced in the same manner as described above.

  FIG. 20 shows a comparative developing device that has a developer supply and recovery member but does not have a third stirring member.

  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).

  It should be noted that the toner supply port 813 is formed in each of the developing devices 1 to 10 and 12 to 21 according to the present invention at a portion where the second stirring member and the third stirring member face each other (perpendicular to the longitudinal direction). When viewed in cross-section, it is the upper position in the middle of both members, and is a position 15 mm downstream from the upstream edge in the overall developer transport direction by the second stirring member.

  On the other hand, the formation position of the toner supply port 813 in each of the developing devices 11 and 22 for comparison is an upper position on the rear side of the second stirring member, and is in the overall conveyance direction of the developer by the second stirring member. It is a position 15 mm downstream from the upstream edge.

  As the developer, a two-component developer having a toner concentration of 7% by mass was used for any of the developers related to yellow toner, magenta toner, cyan toner, and black toner.

  The developer loading amount is 850 g for developing devices 1, 3, 4, 5, 7, 8, 10, 880 g for 2, 6, 9, 750 g for 11, 12, 14, 15, 16, 18, 19, 21 Is 1100 g, 13, 17 and 20 are 1130 g, and 22 is 1000 g.

  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.

  In any of the developers related to the toner, the carrier has a volume average particle diameter of 25 μm and a saturation magnetization of 60 emu / g on the surface of the ferrite particles, and the coating amount of the acrylic resin on the ferrite particles is 3 mass. What was coated in the state of% was used.

  Each of the developing devices 1 to 10 and 12 to 21 and the comparative developing devices 11 and 22 according to the present invention is mounted on an appropriate driving machine, and the first stirring member, the second stirring member, and the third stirring member are rotated. The amount was set as shown in Table 1 below, and the developer transfer amount was measured.

  The results are shown in Table 1 below.

  Note that the developer movement amount is measured by driving another rotating member without driving the developer supply / recovery member and the developer carrying / recovering member when the developer carrier and developer supply / recovery member are present. This was performed by measuring the weight 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 first stirring member in the direction.

  In Table 1, the “rotation direction” related to the first agitating member is the moving direction when viewed from the position close to the developer carrying member, and in the configuration where the developer supply / recovery member is present, The movement direction when it sees in the near opposing position with an agent supply collection | recovery member is shown.

  Further, the “movement direction in the second / third opposed portion” indicates the movement direction of both the agitating members when viewed in the proximity facing position between the second agitating member and the third agitating member.

[Image forming apparatus]
According to the configuration shown in FIG. 1, an image forming apparatus for forming a color image on which each of the developing devices 1 to 22 was mounted was manufactured, and an image output test was performed under the following image forming conditions.

The image forming conditions were set to be the same for all of the image forming units related to the respective color toner images.
<Image forming conditions>
-Process speed (V): 220 mm / sec (number of images formed per minute is 50)
The number of rotations of the developer carrying member (developing sleeve) is adjusted within the range of 210 to 280 rpm, and the toner adhesion amount (M) per unit area on the photosensitive drum is 0.4 mg / cm ^2. did.

-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 when viewed from the developer conveying direction by the first stirring member, and the toner replenishment motor is driven according to the detection result. Controlled.

-Toner replenishment speed: Max. 30 g / min
Photoconductor surface potential: Maximum exposed portion potential (VL): -50V to -100V
Charging potential (VH): Control was made so that VH = Vdc−150 V according to 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, measure the relative reflection density of the white part of the character / line pattern when the reflection density of unused paper is 0, and the relative reflection density is only in a normal temperature and humidity environment (20 ° C., 50%). A case where the relative reflection density is 0.004 or less in all environments of low temperature and low humidity (10 ° C., 20%) / high temperature and high humidity (30 ° C., 80%) 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 contamination is observed, or when only a slight contamination is seen only in the developing device mounting portion, “○” is indicated, and slight contamination 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 developing device numbers in Table 2 correspond to the developing device numbers in Table 1.

<Experimental example 2>
[Production of development device]
In each of the developing devices 1 to 22 used in Experimental Example 1, a recycled toner supply port 825 was formed at a position 8 mm upstream of the toner supply port 813 in the overall developer conveyance direction by the second stirring member. Developing devices (developing device numbers in all tables are unified for easy understanding) 1 to 22 were prepared.

  The recycled toner supply port 825 in the developing device for comparison is shown in FIGS. 19 and 20 in relation to the toner supply port 813.

  In the configuration shown in FIG. 18, an image forming apparatus for forming a monochrome image having a toner recycling unit on which each of the developing devices 1 to 22 is mounted was 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.

The process speed of the image forming apparatus is set to 320 mm / sec (the number of images formed per minute is 65), and the image forming conditions similar to those of the image forming unit relating to the black (BK) toner image of Experimental Example 1 are used. Below, the image output of the following (7) to (9) is repeated 8 times (a total of A4 × 2000). According to the image output test, the presence / absence of fogging of character / line pattern, the presence / absence of character scattering, In addition, the presence / absence of occurrence of internal contamination was evaluated based on the above-mentioned evaluation criteria, and the presence / absence of occurrence of solid density image density unevenness 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 (BK) solid pattern page, the relative reflection density at all locations is 1.3 or more, and the maximum and minimum values. The case where the difference is 0.1 or less is “◯”, 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 “△”, and 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 is “x”.

  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 image forming apparatus for comparison, image fogging, character scattering, image density unevenness, and in-machine contamination occur, and it is difficult to reliably obtain a high-quality image.

1 is a schematic diagram illustrating a first embodiment of an image forming apparatus. 1 is a plan view showing a first embodiment of a developing device. 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 figure which shows 2nd Embodiment of a developing device. It is a figure 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. 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 figure which shows 4th Embodiment of a developing device. It is AA sectional drawing of FIG. It is a figure which shows 2nd Embodiment of an image forming apparatus. It is a figure which shows the image development apparatus for a comparison which does not have a 3rd stirring member. It is a figure which shows the developing device for a comparison which has a developing agent supply collection | recovery member, but does not have the 3rd 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

Claims (21)

A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
A third stirring member having a large outer diameter and a small length in the rotation axis direction with respect to the second stirring member, and having no ability to convey developer in the rotation axis direction; Provided facing the second stirring member in a region corresponding to the upstream side in the developer conveying direction by the second stirring member,
The second stirring member and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided between the second stirring member and the third stirring member on the cover in a region corresponding to the upstream side in the developer transport direction by the second stirring member. Provided
A developing device. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Third agitation, which has a small length in the direction of the rotation axis with respect to the second agitation member and is driven at a high rotation speed but does not have the ability to convey the developer in the direction of the rotation axis. A member is provided opposite to the second stirring member in a region corresponding to the upstream side in the developer conveying direction by the second stirring member;
The second stirring member and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided between the second stirring member and the third stirring member on the cover in a region corresponding to the upstream side in the developer transport direction by the second stirring member. Provided
A developing device. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Third agitation which has a small length in the direction of the rotation axis with respect to the second agitation member and is driven at a high peripheral speed but does not have the ability to convey the developer in the direction of the rotation axis. A member is provided opposite to the second stirring member corresponding to the upstream side of the second stirring member in the developer conveying direction;
The second stirring member and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided between the second stirring member and the third stirring member on the cover in a region corresponding to the upstream side in the developer transport direction by the second stirring member. Provided
A developing device. The third stirring member has a rotating shaft and a plurality of plate-like members provided to be inclined in the same direction with respect to the rotating shaft. The developing device described. The third agitating member is configured integrally with the rotation shaft, a plurality of plate-like members provided in an inclined direction with respect to the rotation shaft, and the plate-like member. 4. The developing device according to claim 1, further comprising: a plate-like rib having a gap and extending in a rotation axis direction. 5. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
The second agitating member is lower in developer conveying capability in the rotation axis direction than the first agitating member, and is located on the downstream side in the developer conveying direction by the first agitating member; It has substantially the same developer conveying capability as the agitating member, and comprises a stirring portion 2B positioned on the upstream side of the developer conveying direction by the first agitating member,
The outer diameter of the second stirring member is larger than the outer diameter of the second stirring member, and the developer conveying ability is substantially the same as or lower than the stirring portion 2A, and the same as the conveying direction of the second stirring member. A third agitating member for agitating while conveying the developer in the direction is disposed opposite to the agitating portion 2A;
The stirring portion 2A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from above to below, and
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
The second agitating member is lower in developer conveying capability in the rotation axis direction than the first agitating member, and is located on the downstream side in the developer conveying direction by the first agitating member; It has substantially the same developer conveying capability as the agitating member, and comprises a stirring portion 2B positioned on the upstream side of the developer conveying direction by the first agitating member,
Conveying of the second agitating member having a developer conveying capacity substantially the same as or lower than that of the agitating portion 2A and driven at a higher rotational speed than the rotational speed of the second agitating member. A third agitating member that agitates the developer while conveying the developer in the same direction as the direction opposite to the agitating portion 2A;
The stirring portion 2A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from above to below, and
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
The second agitating member is lower in developer conveying capability in the rotation axis direction than the first agitating member, and is located on the downstream side in the developer conveying direction by the first agitating member; It has substantially the same developer conveying capability as the agitating member, and comprises a stirring portion 2B positioned on the upstream side of the developer conveying direction by the first agitating member,
It has substantially the same or lower developer conveying ability than the stirring portion 2A, has a peripheral speed higher than the peripheral speed of the second stirring member, and transports the second stirring member. A third agitating member that agitates the developer while conveying the developer in the same direction as the direction opposite to the agitating portion 2A;
The stirring portion 2A and the third stirring member are viewed at their opposing proximity points, and the peripheral surface is movable in the forward direction from above to below, and
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device. The third stirring member includes a rotation shaft, a plurality of plate-like members provided around the rotation shaft in a first direction with respect to the rotation shaft, and a plurality provided in a second direction. The developing device according to claim 6, further comprising: a plate-shaped member. 9. The developing device according to claim 6, wherein the third stirring member includes a plate-like rib extending in a longitudinal direction of the rotation shaft with a gap from the rotation shaft. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Development of the first agitating member, wherein the second agitating member has a developer conveying ability lower than that of the first agitating member and is configured to convey the developer in the same direction as the conveying direction by the first agitating member. The first stirring member 2A positioned on the downstream side in the developer transport direction has substantially the same developer transport capability as the first stirring member, and is positioned upstream in the transport direction of the developer by the first stirring member. It comprises a stirring part 2B that transports the developer in the direction opposite to the transport direction of the stirring member,
A third agitating member that has a larger developer conveying capacity than the first agitating member and that agitates while conveying the developer in a direction opposite to the conveying direction of the first agitating member faces the agitating portion 2A. And the outer diameter of the third stirring member is larger than the outer diameter of the second stirring member,
The stirring part 2A and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Development of the first agitating member, wherein the second agitating member has a developer conveying ability lower than that of the first agitating member and is configured to convey the developer in the same direction as the conveying direction by the first agitating member. The agitating part 2A positioned on the downstream side in the agent conveying direction and the developer conveying ability substantially the same as the first agitating member, and positioned on the upstream side in the developer conveying direction by the first agitating member, 1 a stirring portion 2B that transports the developer in the direction opposite to the developer transport direction by the stirring member,
The developer has a larger developer conveying capacity than the first agitating member and is driven at a higher rotational speed than the second agitating member so as to be opposite to the conveying direction of the first agitating member. A third agitating member for agitating while conveying is disposed opposite the agitating portion 2A, and
The stirring part 2A and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device. A developer carrying member for carrying and conveying a developer including toner and a carrier, a first stirring member provided adjacent to the longitudinal direction of the developer carrying member and stirring the developer in a predetermined direction; A second stirring member that is provided adjacent to the longitudinal direction of the first stirring member and that stirs while transporting the developer in a direction opposite to the transport direction of the developer by the first stirring member; and the developer carrier, In the developing device comprising the first agitating member and the housing for rotatably supporting the second agitating member and a cover provided on the upper portion of the housing,
The first stirring member and the second stirring member, which have substantially the same developer transport capability in the rotation axis direction, are extended to the side corresponding to the downstream side in the developer transport direction by the first stirring member, and With a configuration that protrudes beyond the end of the developer carrier,
Development of the first agitating member, wherein the second agitating member has a developer conveying ability lower than that of the first agitating member and is configured to convey the developer in the same direction as the conveying direction by the first agitating member. The first stirring member 2A positioned on the downstream side in the developer transport direction has substantially the same developer transport capability as the first stirring member, and is positioned upstream in the transport direction of the developer by the first stirring member. It comprises a stirring portion 2B that transports the developer in the direction opposite to the developer transport direction by the stirring member,
The developer has a peripheral speed higher than the peripheral speed of the second agitating member, has a larger developer conveying capability than the first agitating member, and has developer in a direction opposite to the conveying direction of the first agitating member. A third stirring member that is stirred while being conveyed is disposed opposite to the stirring portion 2A;
The stirring part 2A and the third stirring member are configured so that the peripheral surface is movable in the forward direction from the upper side to the lower side when viewed at the opposing proximity point of both,
A toner supply port for supplying toner is provided on the cover corresponding to the upstream region between the stirring portion 2A and the third stirring member and in the developer transport direction by the third stirring member. The
A developing device. The stirring portion 2A includes a rotating shaft, a plurality of plate-like members provided around the rotating shaft and inclined in the first direction with respect to the rotating shaft, and a plurality of members provided inclined in the second direction. The developing device according to claim 11, wherein the developing device includes a plate-like member. 14. The developing device according to claim 11, wherein the stirring portion 2 </ b> A includes a plate-like rib extending in a longitudinal direction of the rotation shaft with a gap between the rotation shaft and the rotation shaft. . The developing device according to any one of claims 1 to 15, wherein the developer carrying member and the first stirring member move in directions opposite to each other when viewed from their proximity points. A developer conveyed by the first stirring member is supplied to the developer carrier between the developer carrier and the first stirring member, and the developer is supplied from the developer carrier to the first stirring member. A rotatable developer supply and recovery member for collecting
The developing device according to any one of claims 1 to 15, wherein the developer supply / recovery member and the developer carrying member move in directions opposite to each other when viewed from their proximity points. . 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 17, 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 18 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 first stirring member is W [g / sec], and the rotation speed of the first 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 Transfer means for transferring an image to a transfer material or intermediate transfer member, cleaning means for cleaning the surface of the image carrier after transfer, and toner removed from the surface of the image carrier by the cleaning means are supplied to the developing means. In an image forming apparatus having toner recycling means for recycling
The developing device according to any one of claims 1 to 18 is used as the developing unit, and the position is on the cover of the developing device and between the stirring portion 2A and the third stirring member. An image forming apparatus comprising a recycled toner supply port for supplying recycled toner. 21. The image forming apparatus according to claim 20, wherein the recycled toner supply port is upstream of the toner supply port.

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