JP2012226191A - Developing device and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device easy to be assembled and able to restrain scattering of toner and falling of toner with less stress on developer on a developer carrier, and an image forming apparatus using the developing device.SOLUTION: The developing device includes: a first inlet seal 4 whose one end is fixed to an aperture end part 131 of a developing casing 13, upstream from a developing area in the moving direction of a developing roller and whose other end is provided in contact with a photoreceptor 1, thereby closing a gap between the aperture end part 131 of the developing casing 13 and the photoreceptor 1; and a second inlet seal 5 whose one end is fixed to the internal wall part of the developing casing 13, farther away from the photoreceptor 1 than the one end of the first inlet seal 4 and whose other end suspends by its own weight, thereby contacting developer on the developing roller 3, which has passed through a regulation position by a doctor blade 12.

Description

  The present invention relates to a developing device that performs development using a two-component developer, and an image forming apparatus such as a copying machine, a printer, and a facsimile machine using the developing device.

  In a developing device equipped in an image forming unit using an electrophotographic system, a two-component developer composed of toner and a magnetic carrier is supported on a developer carrier, and a magnetic brush is formed by a fixed magnetic pole inside the developer carrier. There is known a developing device that performs development. In this developing device, after the developer layer thickness is regulated by a developer regulating member such as a doctor blade, the developer carried on the developer carrying member is moved to the latent image carrying member by moving the surface of the developer carrying member. Transport to opposite development area. At that time, the developer is affected by centrifugal force or airflow in the developing device, and causes scattering of the carrier or toner (hereinafter referred to as “developing of the developer”). The scattering of the developer to the outside of the developing casing is not preferable because it contaminates the inside of the image forming apparatus, for example, the developer adheres to the upstream side of the developing area on the latent image carrier. Therefore, as a countermeasure against these problems, it is common to install a developer scattering prevention sheet that closes the gap between the opening edge of the developing casing and the surface of the latent image carrier on the upstream side of the developer carrier moving direction in the development region. is there. However, even if a general developer scattering prevention sheet is initially effective, the developer scattered on the surface of the developer scattering prevention sheet facing the developer carrying member adheres to the surface of the developer scattering prevention sheet over time. Accumulation tends to occur. When such toner accumulation occurs, various kinds of problems such as a drop of toner falling and an abnormal image occur due to some impact.

  Therefore, for example, in Patent Document 1, in addition to the developer scattering prevention sheet described above, a developer accumulation prevention sheet is provided so as to cover the developer layer after passing the restriction position of the developer restriction member. One end of the developer accumulation preventing sheet is fixed to the inner wall portion of the developing casing, and the free end is in contact with the end portion of the developer scattering preventing sheet. As a result, it is possible to suppress the scattered developer from adhering to the surface of the developer scattering prevention sheet facing the developer carrier. Further, even if the scattered toner adheres to the developer accumulation preventing sheet instead of the developer scattering prevention sheet, the surface of the developer accumulation preventing sheet that faces the developer carrying member depends on the developer on the developer carrying member. Because of rubbing, toner accumulation is unlikely to occur in the developer accumulation preventing sheet.

  However, the developer accumulation preventing sheet described above is installed with one end abutting against the end of the developer scattering prevention sheet. For this reason, it is difficult to assemble the developer accumulation preventing sheet into the developing device. In addition, since one end of the developer pool prevention sheet is abutted against and fixed to the end portion of the developer scattering prevention sheet, the developer on the developer carrying member is easily stressed and uneven conveyance is likely to occur.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress toner scattering and toner dropping in a state where assembly is easy and stress is small with respect to the developer on the developer carrying member. It is an object of the present invention to provide a developing device and an image forming apparatus using the same.

In order to solve the above problems, the invention of claim 1 is arranged to face the surface of the latent image carrier with a part thereof exposed from the opening of the developing casing, and carries a developer composed of toner and carrier on the surface. The developer carrying member that moves on the surface and supplies toner to the latent image on the surface of the latent image carrying member in a developing region facing the latent image carrying member and develops the toner image. And a developer regulating member that is disposed to face the gap and regulates the amount of developer carried on the developer carrying member, one end of the developer carrying member moving direction upstream of the developing region A first seal member that is fixed to the opening edge of the developing casing and whose other end contacts the latent image carrier, thereby closing a gap between the opening edge of the developing casing and the latent image carrier; One end is carrying the latent image than one end of the first seal member A second seal member fixed to the inner wall portion of the developing casing at a position away from the second casing and contacting the developer on the developer carrying member whose other end hangs down due to its own weight and has passed the restriction position by the developer restriction member; It is characterized by providing.
According to a second aspect of the present invention, in the developing device according to the first aspect, the second seal member bends in an arc shape with a predetermined gap from the surface of the developer carrier, and is fixedly disposed inside the developer carrier. The magnetic brush is brought into contact with the tip of a magnetic brush that is raised by a magnetic field generated by the magnetic field generating means.
According to a third aspect of the present invention, in the developing device of the second aspect, the other end of the second seal member is a magnetic brush by a developing main pole of the magnetic field generating means, and the developing main pole of the magnetic field generating means. Further, it is located between the magnetic brush by the conveying magnetic poles arranged adjacent to the upstream side of the developing roller moving direction and at the place where the ears are sleeping.
According to a fourth aspect of the present invention, a latent image carrier and a two-component developer comprising a toner and a carrier are conveyed to a development area facing the latent image carrier, and the toner is applied to the latent image on the latent image carrier. An image forming an image on the recording material by transferring a toner image obtained by development by the developing device from the latent image carrier to the recording material. In the forming apparatus, the developing device according to claim 1, 2, or 3 is used as the developing device.

  In the present invention, since the gap between the developing casing and the developing carrier is closed by the first seal member, the developer that has passed the restriction position by the developer restricting member is scattered outside the developing casing. Can be suppressed. Further, the second seal member is reliably brought into contact with the developer on the developer carrier that has passed through the regulation position by the developer regulating member with the other end depending on its own weight, and is opposed to the developer carrier of the second seal member. The surface to be rubbed is rubbed by the developer. Therefore, it is possible to suppress the developer from adhering to and accumulating on the surface of the second seal member facing the developer carrier. Further, since the second seal member has a configuration in which the other end hangs down under its own weight and comes into contact with the developer on the developer carrier, the seal member that is fixed at both ends and comes into contact with the developer on the developer carrier. As compared with the above, there is less stress on the developer on the developer carrying member, and developer conveyance unevenness is less likely to occur. Moreover, since the other end of the second seal member hangs down under its own weight, the second seal member is easier to assemble than when the other end is abutted against the end of another seal member and assembled in the apparatus.

  The present invention provides a developing device that can be easily assembled and can suppress toner scattering and toner dropping in a state in which stress on the developer on the developer carrying member is low, and an image forming apparatus using the same. There is an excellent effect of being able to.

1 is a configuration diagram illustrating a schematic configuration of a copier according to an embodiment. FIG. 2 is a configuration diagram illustrating a schematic configuration of an image forming unit of the copier. FIG. 3 is a partially enlarged configuration diagram illustrating a partial configuration of a developing device of the image forming unit.

  Hereinafter, as an example of an image forming apparatus using a developing device according to an embodiment of the present invention, an embodiment of a tandem type color laser copier (hereinafter simply referred to as “copier”) in which a plurality of photoconductors are arranged in parallel. A form is demonstrated. FIG. 1 is a configuration diagram illustrating a schematic configuration of a copier according to the present embodiment. The copying machine includes a printer unit 100, a paper feeding device 200 on which the printer unit 100 is placed, a scanner 300 fixed on the printer unit 100, and the like. An automatic document feeder 400 fixed on the scanner 300 is also provided.

  The printer unit 100 includes four sets of image forming units 20Y, 20M, 20C, and 20K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). Yes. Y, M, C, and K attached to the numbers of the respective symbols indicate members for yellow, cyan, magenta, and black (the same applies hereinafter). In addition to the image forming units 20Y, 20M, 20C, and 20K, an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer device 22, a resist roller pair 49, a belt fixing type fixing device 25, and the like are disposed. Yes.

  The optical writing unit 21 has a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of a photoconductor described later with laser light based on image data.

  The image forming units 20Y, 20M, 20C, and 20K each support a charger, a developing device 2, a drum cleaning device, a static eliminator, and the like provided around the drum-shaped photoreceptor 1 as a unit on a common support. It can be attached to and detached from the main body of the image forming apparatus 1.

  Hereinafter, the yellow image forming unit 20Y will be described. The surface of the photoreceptor 1Y is uniformly charged by a charger as charging means. The surface of the photoreceptor 1 </ b> Y that has been subjected to charging processing is irradiated with laser light that has been modulated and deflected by the optical writing unit 21. Then, the potential of the irradiation part (exposure part) is attenuated. By this attenuation, an electrostatic latent image for Y is formed on the surface of the photoreceptor 1Y. The formed electrostatic latent image for Y is developed by the developing device 2Y as developing means to become a Y toner image. The Y toner image formed on the Y photoconductor 1Y is primarily transferred to an intermediate transfer belt 110 described later. The surface of the photoreceptor 1Y after the primary transfer is cleaned of the transfer residual toner by a drum cleaning device. In the Y image forming unit 20Y, the photoreceptor 1Y cleaned by the drum cleaning device is discharged by the charge eliminator. Then, it is uniformly charged by the charger and returns to the initial state. The series of processes as described above is the same for the other image forming units 20M, 20C, and 20K.

  Next, the intermediate transfer unit 17 will be described. The intermediate transfer unit 17 includes an intermediate transfer belt 110, a belt cleaning device 90, and the like. Further, it also includes a tension roller 14, a driving roller 15, a secondary transfer backup roller 16, four primary transfer bias rollers 62Y, M, C, and K. The intermediate transfer belt 110 is tensioned by a plurality of rollers including the tension roller 14. Then, it is endlessly moved clockwise in the drawing by the rotation of the driving roller 15 driven by a belt driving motor (not shown). The four primary transfer bias rollers 62Y, 62M, 62C, and 62K are disposed so as to be in contact with the inner peripheral surface side of the intermediate transfer belt 110, respectively, and receive primary transfer bias from a power source (not shown).

  Further, the intermediate transfer belt 110 is pressed toward the photoreceptors 1Y, 1M, 1C, and 1K from the inner peripheral surface side to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photoreceptors 1Y, 1M, 1C, and 1K and the primary transfer bias rollers 62Y, M, C, and K due to the influence of the primary transfer bias. The above-described Y toner image formed on the Y photoconductor 1Y is primarily transferred onto the intermediate transfer belt 110 due to the influence of the primary transfer electric field and nip pressure. On the Y toner image, the M, C, K toner images formed on the M, C, K photoconductors 1M, C, K are sequentially superposed and primarily transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image) that is a multiple toner image is formed on the intermediate transfer belt 110.

  The four-color toner image superimposed and transferred onto the intermediate transfer belt 110 is secondarily transferred onto a transfer sheet (not shown) as a recording sheet at a secondary transfer nip described later. Transfer residual toner remaining on the surface of the intermediate transfer belt 110 after passing through the secondary transfer nip is cleaned by a belt cleaning device 90 that sandwiches the belt with the driving roller 15 on the left side in the drawing.

  Next, the secondary transfer device 22 will be described. Below the intermediate transfer unit 17 in the figure, a secondary transfer device 22 is disposed in which a paper conveying belt 24 is stretched by two stretching rollers 23. The paper transport belt 24 is moved endlessly in the counterclockwise direction in the drawing in accordance with the rotational drive of at least one of the stretching rollers 23. One of the two stretching rollers 23 arranged on the right side in the drawing sandwiches the intermediate transfer belt 110 and the paper transport belt 24 between the secondary transfer backup roller 16 of the intermediate transfer unit 17. It is out. By this sandwiching, a secondary transfer nip is formed in which the intermediate transfer belt 110 of the intermediate transfer unit 17 and the paper transport belt 24 of the secondary transfer device 22 are in contact with each other.

  A secondary transfer bias having a polarity opposite to that of the toner is applied to the one stretching roller 23 by a power source (not shown). By applying this secondary transfer bias, the four-color toner image on the intermediate transfer belt 110 of the intermediate transfer unit 17 is electrostatically moved from the belt side toward the one stretching roller 23 side in the secondary transfer nip. A next transfer electric field is formed. The transfer sheet fed to the secondary transfer nip so as to be synchronized with the four-color toner image on the intermediate transfer belt 110 by the registration roller pair 49 has a four-color toner image affected by the secondary transfer electric field and nip pressure. Is secondary transferred. Instead of the secondary transfer method in which the secondary transfer bias is applied to one of the stretching rollers 23 as described above, a charger for charging the transfer paper in a non-contact manner may be provided.

  In a paper feeding device 200 provided at the lower portion of the copying machine main body, a plurality of paper feeding cassettes 44 are accommodated in multiple stages in the paper bank 43 in the vertical direction. In each paper feed cassette 44, a plurality of transfer sheets are accommodated in a stack of sheets. Each paper feed cassette 44 presses the paper feed roller 42 against the uppermost transfer paper in the paper bundle. Then, by rotating the paper feed roller 42, the uppermost transfer paper is sent out toward the paper feed path 46.

  The paper feed path 46 that receives the transfer paper fed from the paper feed cassette 44 has a plurality of conveying roller pairs 47 and a registration roller pair 49 provided near the end in the path. Then, the transfer paper is conveyed toward the registration roller pair 49. The transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49.

  On the other hand, in the intermediate transfer unit 17, the four-color toner image formed on the intermediate transfer belt 110 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the transfer paper can be brought into close contact with the four-color toner image at the secondary transfer nip. Thereby, in the secondary transfer nip, the four-color toner image on the intermediate transfer belt 110 is in close contact with the transfer paper. Then, it is secondarily transferred onto the transfer paper and becomes a full color image on the white transfer paper. The transfer paper on which the full-color image is formed in this manner exits the secondary transfer nip as the paper transport belt 24 moves endlessly, and then is sent from the paper transport belt 24 to the fixing device 25.

  The fixing device 25 includes a belt unit that moves the fixing belt 26 endlessly while being stretched by two rollers, and a pressure roller 27 that is pressed toward one roller of the belt unit. The fixing belt 26 and the pressure roller 27 are in contact with each other to form a fixing nip, and the transfer paper received from the paper transport belt 24 is sandwiched therebetween. Of the two rollers in the belt unit, the roller that is pressed from the pressure roller 27 has a heat source (not shown) inside, and pressurizes the fixing belt 26 by the heat generated therefrom. The pressed fixing belt 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure.

  The transfer paper that has been subjected to the fixing process in the fixing device 25 is discharged onto a stack portion 57 projecting from the left side plate in the drawing of the casing of the copying machine by a discharge roller 56 or on the other surface. Also, it is returned to the above-described secondary transfer nip to form a toner image.

  When a document (not shown) is copied, for example, a bundle of sheet documents is set on the document table 30 of the automatic document feeder 400. However, when the original is a single-sided original that is closed in a main form, it is set on the contact glass 32. Prior to this setting, the automatic document feeder 400 is opened with respect to the copying machine main body, and the contact glass 32 of the scanner 300 is exposed. Thereafter, the single-bound original is pressed by the closed automatic document feeder 400.

  When a copy start switch (not shown) is pressed after the document is set in this way, the document reading operation by the scanner 300 starts. However, when a sheet document is set on the automatic document feeder 400, the automatic document feeder 400 automatically moves the sheet document to the contact glass 32 prior to the document reading operation. In the document reading operation, first, the first traveling body 33 and the second traveling body 34 both start traveling, and light is emitted from a light source provided in the first traveling body 33. Then, the reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, passes through the imaging lens 35, and then enters the reading sensor 36. The reading sensor 36 constructs image information based on the incident light.

  In parallel with such a document reading operation, each device in each of the image forming units 20Y, 20M, 20C, 20K, the intermediate transfer unit 17, the secondary transfer device 22, and the fixing device 25 starts driving. Based on the image information constructed by the reading sensor 36, the optical writing unit 21 is driven and controlled, and Y, M, C, and K toner images are formed on the photoreceptors 40Y, 40M, 40C, and 40K. Is done. These toner images become four-color toner images superimposed and transferred on the intermediate transfer belt 110.

  Further, almost simultaneously with the start of the document reading operation, the paper feeding operation is started in the paper feeding device 200. In this paper feeding operation, one of the paper feeding rollers 42 is selectively rotated, and the transfer paper is sent out from one of the paper feeding cassettes 44 accommodated in the paper bank 43 in multiple stages. The fed transfer sheets are separated one by one by the separation roller 45 and enter the reverse feeding path 46, and then conveyed toward the secondary transfer nip by the conveyance roller pair 47. In some cases, paper feeding from the manual feed tray 51 is performed instead of such paper feeding from the paper feeding cassette 44. In this case, after the manual feed roller 50 is selectively rotated to feed the transfer paper on the manual feed tray 51, the separation roller 52 separates the transfer paper one by one and feeds it to the manual feed path 53 of the printer unit 100. Make paper.

  In the case of forming another color image composed of two or more colors of toner, the copying machine stretches the intermediate transfer belt 110 so that the upper stretched surface thereof is substantially horizontal, Photoconductors 1Y, 1M, 1C, and 1K are brought into contact with each other. On the other hand, when forming a monochrome image consisting of only K toner, the intermediate transfer belt 110 is tilted to the lower left in the drawing by a mechanism (not shown) and the upper stretched surface is set to Y, M, C. The photoconductors 1Y, 1M, and 1C are separated. Of the four photoconductors 1Y, 1M, 1C, and 1K, only the K photoconductor 1K is rotated counterclockwise in the drawing to form only the K toner image. At this time, for Y, M, and C, not only the photosensitive member 1 but also the developing device 2 is stopped to prevent unnecessary consumption of the photosensitive member 1 and the developer.

  The copying machine includes a control unit (not shown) configured by a CPU that controls the following devices in the copying machine, and an operation display unit (not shown) configured by a liquid crystal display, various key buttons, and the like. The operator sends a command to the control unit by a key input operation on the operation display unit, so that one of the three modes is selected from the three-sided print mode, which is a mode for forming an image only on one side of the transfer paper. You can choose one. The three single-sided printing modes include a direct discharge mode, a reverse discharge mode, and a reverse decal discharge mode.

  FIG. 2 is a configuration diagram illustrating a schematic configuration of the image forming unit. Since the four image forming units 20Y, 20M, 20C, and 20K have substantially the same configuration except that the toner colors to be handled are different, the subscripts Y, M, C, and K are omitted in FIG. ing.

  The developing device 2 mainly includes a developing roller 3 as a developer carrying member that carries a two-component developer composed of toner and a magnetic carrier, and a developing casing 13 that contains the developer inside. The developing casing 13 is opened at a position facing the surface of the photosensitive member 1 that rotates in the clockwise direction in the drawing, and a part of the developing roller 3 that rotates in the clockwise direction in the drawing is exposed from the opening. Yes. The developing roller 3 is disposed so that the surface portion exposed from the opening is slightly spaced from the surface of the photoreceptor 1. The developing roller 3 includes a cylindrical developing sleeve formed of a conductive and nonmagnetic material, and a magnet roller in which a plurality of magnetic poles are fixedly arranged inside the developing sleeve. When the developing sleeve is driven to rotate, the developing sleeve moves relative to the magnet roller, and rotates in a rotating direction with respect to the surface moving direction of the photoreceptor 1. The developing sleeve is connected to a power supply (not shown) for applying a developing bias. When a developing bias is applied to the developing sleeve, a developing electric field is formed in a developing region where the surface of the developing roller 3 and the surface of the photoreceptor 1 face each other. By this developing electric field, the toner in the developer carried on the surface of the developing roller 3 adheres to the electrostatic latent image formed on the photoreceptor 1 and development is performed. At the time of development, in the development area, the magnetic carrier in the developer on the developing roller 3 is in a state where the magnetic brush is raised by the action of the magnetic field formed by the magnet roller.

  Further, the developing device 2 includes a doctor blade 12 as a developer regulating member that regulates the amount of developer carried on the surface of the developing roller 3 and conveyed to the developing region, and a developing casing 13 that extends to the doctor blade 12. The opening edge 131 is provided with a first inlet seal and a second inlet seal described later. Further, the developing device 2 collects the developer that has been passed through the developing region by collecting a supply screw 8 that conveys the developer toward the front of FIG. A recovery screw 6 that transports the developer in the same direction as the supply screw 8 is provided. A supply conveyance path 9 provided with a supply screw 8 is provided in the lateral direction of the developing roller 3, and a collection conveyance path 7 provided with a collection screw 6 is provided in parallel below the development roller 3. Further, the developing device 2 is provided with an agitation conveyance path 10 in parallel with the collection conveyance path 7 below the supply conveyance path 9. The agitating and conveying path 10 includes an agitating screw 11 as a developer agitating and conveying member that conveys the developer to the back side in the figure, which is the direction opposite to the supply screw 8 while agitating the developer.

  The supply conveyance path 9 and the agitation conveyance path 10 are partitioned by a first partition wall 133 as a partition member. In the first partition wall 133, the supply conveyance path 9 and the agitation conveyance path 10 are partitioned at both ends on the front side and the back side in the drawing, and the supply conveyance path 9 and the agitation conveyance path 10 communicate with each other. is doing. Further, the two conveyance paths of the stirring conveyance path 10 and the collection conveyance path 7 are partitioned by a second partition wall 134 as a partition member. The second partition wall 134 has an opening on the front side in the figure, and the agitation transport path 10 and the collection transport path 7 communicate with each other. The supply conveyance path 9 and the recovery conveyance path 7 are both partitioned by the first partition wall 133, but an opening is provided at a location where the supply conveyance path 9 and the recovery conveyance path 7 of the first partition wall 133 are partitioned. Absent.

  The developer after development is collected in the collection conveyance path 7, conveyed to the front side of the cross section in FIG. 2, and to the agitation conveyance path 10 through the opening of the second partition wall 134 provided in the non-image area portion. Developer is transferred. The toner and the carrier are mixed in advance in the stirring and conveying path 10 from the toner replenishing port provided on the upper side of the stirring and conveying path 10 near the opening of the first partition wall 133 on the upstream side in the developer conveying direction in the stirring and conveying path 10. The premixed toner that becomes the developed developer is supplied.

  Further, the supply conveyance path 9 allows a part of the developer in the supply conveyance path 9 to be supplied to the outside of the development apparatus 2 when the amount of developer in the development apparatus 2 becomes larger than necessary due to replenishment of premix toner or the like. A discharge conveyance path 18 for discharging is provided. The discharge conveyance path 18 includes a developer discharge port 18 a and a discharge conveyance screw 18 b that conveys the developer discharged from the developer discharge port 18 a to the outside of the developing device 2. The discharge conveyance path 18 is disposed adjacent to the supply conveyance path 9 with the partition wall 135 interposed therebetween, and the developer discharge port 18a is connected to the supply conveyance path 9 at the downstream end of the supply conveyance path 9 in the developer conveyance direction. It is an opening provided in the partition wall 135 so as to communicate with the discharge conveyance path 18.

  Next, the circulation of the developer in the three developer conveyance paths will be described. In the supply conveyance path 9 that receives the supply of the developer from the agitation conveyance path 10, the developer is conveyed downstream in the conveyance direction of the supply screw 8 while supplying the developer to the developing roller 3. Then, the excess developer that is supplied to the developing roller 3 and is not used for development and is transported to the downstream end in the transport direction of the supply transport path 9 is supplied to the agitation transport path 10 from the surplus opening of the first partition wall 133. The collected developer that is sent from the developing roller 3 to the collection conveyance path 7 and conveyed to the downstream end in the conveyance direction of the collection conveyance path 7 by the collection screw 6 is supplied to the stirring conveyance path 10 from the collection opening of the second partition wall 134. The The agitating and conveying path 10 agitates the supplied surplus developer and the recovered developer, conveys the agitating screw 11 to the downstream side in the conveying direction, and conveys it to the upstream side in the conveying direction of the supplying screw 8. It is supplied to the supply conveyance path 9 from the supply opening portion 133.

  In the agitating and conveying path 10, the agitating screw 11 agitates and conveys the collected developer, the surplus developer, and the toner replenished as necessary in the transfer unit in the direction opposite to the developer in the collecting and conveying path 7 and the supply conveying path 9. . Then, the agitated developer is transferred to the upstream side in the conveyance direction of the supply conveyance path 9 communicating with the downstream side in the conveyance direction. A toner concentration sensor (not shown) is provided below the agitation transport path 10, and a toner supply control device (not shown) is operated by the sensor output to supply toner from a toner storage portion (not shown).

  Since the developing device 2 includes the supply conveyance path 9 and the collection conveyance path 7 and supplies and collects the developer in different developer conveyance paths, the developed developer is mixed into the supply conveyance path 9. There is no. Therefore, it is possible to prevent the toner density of the developer supplied to the developing roller 3 from decreasing toward the downstream side of the supply conveyance path 9 in the conveyance direction. Further, since the recovery conveyance path 7 and the agitation conveyance path 10 are provided and the developer recovery and agitation are performed in different developer conveyance paths, the developed developer does not fall during the agitation. Therefore, since the sufficiently agitated developer is supplied to the supply conveyance path 9, it is possible to prevent the developer supplied to the agent supply conveyance path 9 from being insufficiently agitated. In this way, the toner density of the developer in the supply conveyance path 9 can be prevented from decreasing, and the developer in the supply conveyance path 9 can be prevented from being insufficiently stirred. Can be constant.

  As shown in FIG. 4, the developer moves from the lower part to the upper part of the developing device 2 by pushing the developer by the rotation of the stirring screw 11, thereby raising the developer and supplying the developer to the supply conveyance path 9. Supply. Such movement of the developer gives stress to the developer and contributes to a decrease in the life of the developer. That is, when the developer is lifted from the bottom to the top, the developer is stressed, and the carrier film in the developer is scraped off and the toner is spent on the spot, and the stability of the image quality cannot be maintained accordingly. End up. Therefore, the life of the developer can be extended by reducing the stress of the developer during the movement of the developer described above. By prolonging the life of the developer, it is possible to provide a developing device that prevents deterioration of the developer and is always stable in image quality without image density unevenness.

  In the developing device 2 of the present embodiment, as shown in FIG. 2, the supply conveyance path 9 is disposed obliquely above the stirring conveyance path 10. By disposing it obliquely above, it is possible to reduce the developer stress in the movement of the developer indicated by the arrow D, compared to the case where the supply conveyance path 9 is provided vertically above the stirring conveyance path 10 and the developer is lifted. . Further, in the developing device 2, the supply conveyance path 9 and the agitation conveyance path 10 are arranged obliquely so that the upper wall surface of the agitation conveyance path 10 is higher than the lower wall surface of the supply conveyance path 9 as shown in FIG. 2. It arranges so that it may become a position.

  Lifting the supply conveyance path 9 vertically upward with respect to the stirring conveyance path 10 causes the developer to be stressed because the developer is lifted by the pressure of the stirring screw 11 against gravity. On the other hand, the developer present at the highest point of the agitating and conveying path 10 is placed at the bottom of the supplying and conveying path 9 by arranging the upper wall surface of the agitating and conveying path 10 to be higher than the lower wall surface of the supplying and conveying path 9. Since the point can flow without being against gravity, the stress applied to the developer can be reduced.

  Note that a fin member may be provided on the shaft of the stirring screw 11 in a portion where the stirring transport path 10 and the supply transport path 9 communicate with each other on the downstream side of the developer transport path of the stirring transport path 10. This fin member is a plate-like member composed of a side parallel to the axial direction of the stirring screw 11 and a side perpendicular to the axial direction of the stirring screw. By scooping up the developer with this fin member, it is possible to more efficiently deliver the developer from the stirring conveyance path 10 to the supply conveyance path 9.

  Further, in the developing device 2, the center A of the developing roller 3 and the supply transport path 9 is shorter than the center distance B of the developing roller 3 and the stirring transport path 10, and the stirring of the supply transport path 9 and the stirring transport path 9. A conveyance path 10 is arranged. Thereby, the developer can be supplied without difficulty from the supply conveyance path 9 to the developing roller 3, and the apparatus can be downsized. The stirring screw 11 rotates counterclockwise as viewed from the front side in FIG. 2, and the developer lifts the developer along the shape of the stirring screw 11 and transfers it to the supply conveyance path 9. Yes. As a result, the developer can be lifted efficiently, and the stress on the developer can be further reduced.

  Next, the first inlet seal that is a first seal member and the second inlet seal that is a second seal member provided in the developing device that is a feature of the present invention will be described. FIG. 3 is a partially enlarged configuration diagram illustrating a partial configuration of the developing device. As shown in FIG. 3, one end of each of the first inlet seal 4 and the second inlet seal 5 is fixed to the opening edge 131 of the developing casing 13 on the upstream side in the developing roller moving direction from the developing region, and the other end ( The free end is toward the development area. The first inlet seal 4 and the second inlet seal 5 are made of an elastic sheet such as polyurethane (PUR) resin or polyethylene terephthalate (PET) resin.

  As described above, one end of the first inlet seal 4 is fixed to the tip of the opening edge 131 of the developing casing 13 on the upstream side of the developing region in the developing roller moving direction, and the other end (free end) is the photosensitive member 1. It is arranged to contact the surface in the trailing direction. As a result, the gap between the opening edge 131 of the developing casing 13 and the surface of the photoreceptor 1 is closed, and the developer scattering from this gap can be prevented.

  Further, the second inlet seal 5 is fixed to the inner wall portion of the opening edge 131 of the developing casing 13, one end of which is located farther from the photoreceptor 1 than the first inlet seal 4 and close to the doctor blade 12. Then, the other end (free end) hangs down in an arc shape by its own weight, and is arranged so as to contact the developer T until it passes through the doctor blade 12 and is conveyed to the developing region. The gap between the surface of the developing roller 3 and the second inlet seal 5 is set so that the surface of the second inlet seal 5 facing the developing roller 3 is in contact with the tip of a magnetic brush ear formed on the developing roller 3. ing. As a result, the surface of the second inlet seal 5 that faces the developing roller 3 is rubbed by the tip of the tip of the developer T conveyed by the developing roller 3, so that no developer pool occurs and no toner lump is formed. Can prevent problems caused by falling. Further, since the second inlet seal 5 is in contact with the developer T on the developing roller 3 in a state where it hangs down by its own weight, it lies down even when the ear of the developer T on the developing roller 3 stands. Even in this state, contact can be made without stress, and developer conveyance unevenness is less likely to occur compared to contact with an inlet seal whose position is fixed. Further, since the second inlet seal 5 has a configuration in which the other end hangs under its own weight, the second inlet seal 5 is easier to assemble than the case where the other end abuts against the end of another seal member and is assembled in the apparatus.

  The other end (free end) of the second inlet seal 5 at this time is a magnetic brush formed by the developing main pole P1, and a magnetic brush formed by the conveying magnetic pole P2 arranged adjacent to the upstream side in the developing roller moving direction. It is preferable to be located at a place where the ear is sleeping. This is because if the tip of the second inlet seal 5 comes into contact with the head of the developing main pole P1, the magnetic brush is disturbed, and the uniform image is lost. Further, an aluminum vapor deposition layer is provided on the surface of the second inlet seal 5 facing the developing roller 3 so that the second inlet seal 5 has a two-layer structure so that the toner is less likely to adhere to the second inlet seal 5. Also good.

As described above, according to the developing device 2 according to the present embodiment, the toner scattering is suppressed by the first inlet seal 4 that is the first seal member. At the same time, the second inlet seal 5 as the second seal member hardly causes the developer accumulation, and the toner drop to the development area is suppressed. In addition, since the second inlet seal 5 has a configuration in which the other end hangs under its own weight, it can come into contact with the developer on the developing roller 3 in a state of less stress compared to a seal member to which both ends are fixed. And uneven conveyance is unlikely to occur. Further, since the second inlet seal 5 has a configuration in which the other end hangs under its own weight, the second inlet seal 5 is easier to assemble than the case where the other end abuts against the end of another seal member and is assembled in the apparatus.
Further, according to the developing device 2 according to the present embodiment, the second inlet seal 5 bends in an arc shape while maintaining a predetermined gap with the developer roller 3, and the tip of the head of the magnetic brush carried on the developing roller 3. It can be touched gently without stress. As a result, the developer is unlikely to adhere to the surface of the second inlet seal 5 facing the developing roller 3, and the developer is unlikely to accumulate.
Further, according to the developing device 2 according to the present embodiment, the tip of the second inlet seal 5 is located at the place where the ears of the magnetic brush carried on the developing roller 3 are lying, so that the magnetic brush in the developing region. Will not disturb.
Further, according to the copying machine provided with the developing device 2, it is possible to suppress the scattering of the developer and the toner drop from the vicinity of the developing region, and a high quality image can be obtained.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developing apparatus 3 Developing roller 4 First inlet seal 5 Second inlet seal 12 Doctor blade 131 Open edge of developing casing

Japanese Patent No. 4280537

Claims (4)

A developing region that is opposed to the surface of the latent image carrier with a part thereof exposed from the opening of the developing casing, carries a developer composed of toner and carrier on the surface, moves to the surface, and faces the latent image carrier The developer carrying member for supplying toner to the latent image on the surface of the latent image carrying member for development and the developer carrying member are disposed to face each other with a predetermined gap therebetween. In a developing device comprising a developer regulating member that regulates the amount of developer carried on
One end is fixed to the opening edge of the developing casing on the upstream side in the developer carrier moving direction with respect to the developing region, and the other end is in contact with the latent image carrier, whereby the opening edge of the developing casing A first seal member that closes the gap with the latent image carrier;
One end of the first seal member is fixed to the inner wall portion of the developing casing at a position farther from the latent image carrier than the one end of the first seal member, and the other end hangs down by its own weight and passes through the restriction position by the developer restriction member. A developing device comprising: a second seal member that contacts the developer on the developer carrying member. The developing device according to claim 1.
The second seal member bends in an arc shape while maintaining a predetermined gap with the surface of the developer carrying member, and a magnetic brush that rises by a magnetic field generated by a magnetic field generating means fixedly arranged inside the developer carrying member. A developing device that comes into contact with the tips of the ears of the flower. The developing device according to claim 2.
The other end of the second seal member is arranged adjacent to the magnetic brush by the developing main pole of the magnetic field generating means and the upstream side of the developing roller moving direction of the developing main pole of the magnetic field generating means. A developing device, wherein the developing device is located between a magnetic brush by a conveying magnetic pole and where a head is sleeping. A latent image carrier, and a developing device that transports a two-component developer composed of toner and carrier to a development area facing the latent image carrier and attaches the toner to the latent image on the latent image carrier for development An image forming apparatus for forming an image on the recording material by finally transferring the toner image obtained by development by the developing device from the latent image carrier onto the recording material.
An image forming apparatus using the developing device according to claim 1, 2 or 3 as the developing device.

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