JP4539627B2 - Developer supply apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a developer supply device configured to supply a charged developer (dry developer) to a predetermined supply target (photosensitive drum or the like), and an image forming apparatus including the developer supply device. About.

  In the image forming apparatus, many so-called “electric field curtain” mechanisms for conveying the developer using an electric field have been known (for example, Japanese Patent Laid-Open Nos. 59-181371 and 63-13068). No., JP-A 63-13075, JP-A 5-197312, JP-A 2002-351218, JP-A 2003-15417, etc.).

  The electric field curtain mechanism includes a container for containing the developer. A large number of electrodes are arranged in the container. These electrodes are provided on a plate-like member accommodated in the container. Further, these electrodes are connected to a multiphase (for example, three-phase) AC power source.

  The electric field curtain mechanism is configured to convey the charged developer by applying a multiphase AC voltage to the electrodes.

  In the electric field curtain mechanism having such a configuration, a multiphase AC voltage is output from the AC power supply. This multiphase AC voltage is applied to a number of the electrodes. This generates an electric field that can move the developer in a predetermined direction.

By this electric field, the developer in the container is transported in the predetermined direction on the plate-like member. Then, when the developer is supplied to the supply target, image formation is performed in a predetermined developing unit. Thereafter, the developer falls from the plate-like member.
JP 59-181371 A Japanese Patent Laid-Open No. 63-13068 JP 63-13075 A JP-A-5-197312 JP 2002-351218 A JP 2003-15417 A

  In the conventional electric field curtain mechanism as described above, the image quality (density and uniformity) of the formed image may change as the amount of the developer in the container changes. Such a change in image quality is caused by a change in the transport amount of the developer on the plate-like member.

  That is, the amount of the developer conveyed on the plate member varies depending on the amount of the developer in the container. Thereby, the supply amount of the developer to the developing unit varies. Due to the fluctuation of the supply amount, density change and density unevenness occur.

  In particular, when the developer storage amount (reserved amount) in the container decreases, the developer stored in the bottom of the container may not be satisfactorily supplied to the plate member. obtain. In such a case, the shortage of the supply amount of the developer to the developing unit rapidly proceeds, so that the density shortage and the density unevenness may occur rapidly.

  The present invention has been made to solve such problems. That is, an object of the present invention is to provide a developer supply device and an image forming apparatus that can suppress as much as possible a change in image quality due to a change in the amount (storage amount) of developer.

  (1) An image forming apparatus of the present invention includes an electrostatic latent image carrier and a developer supply device.

  The electrostatic latent image carrier has a latent image forming surface. The latent image forming surface is configured such that an electrostatic latent image by a potential distribution can be formed. This latent image forming surface is formed in parallel with a predetermined main scanning direction.

  The electrostatic latent image carrier is configured such that the latent image forming surface can move along a sub-scanning direction orthogonal to the main scanning direction.

  The developer supply device is disposed to face the electrostatic latent image carrier. The developer supply device is configured to supply the developer to the latent image forming surface in a charged state.

  Specifically, the developer supply device in the image forming apparatus of the present invention includes a developer containing casing, a developer transport body, a plurality of first transport electrodes, and a plurality of second transport electrodes. Yes.

  The developer accommodating casing is a box-shaped member and is configured to accommodate the developer. The developer containing casing includes a top plate and a bottom plate provided to face the top plate. An opening is formed in the developer containing casing at a position of the top plate facing the electrostatic latent image carrier.

  The developer transport body has a developer main transport surface parallel to the main scanning direction. The developer transport body is disposed in the developer containing casing so that the developer main transport surface faces the electrostatic latent image carrier with the opening in the top plate interposed therebetween.

  The plurality of first transport electrodes are provided along the developer main transport surface so as to face the latent image forming surface. These first transport electrodes are arranged along the sub-scanning direction. The first transport electrodes are configured to transport the developer in a predetermined developer main transport direction on the developer main transport surface by applying a traveling wave voltage. Yes.

  The plurality of second transport electrodes are provided along a sloped developer sub-transport surface and along the bottom plate of the developer containing casing. These second transport electrodes are arranged along the sub-scanning direction. The second transport electrodes are configured to transport the developer in a predetermined developer sub-transport direction on the developer sub-transport surface by applying a traveling wave voltage. Yes.

  Here, in the image forming apparatus of the present invention, the developer sub-transport surface is formed in a planar shape intersecting with the horizontal plane so that an angle formed with the horizontal plane is constant. For example, the developer sub-transport surface can be formed such that the angle formed with the horizontal plane is always 30 degrees or less.

  In addition, the developer sub-transport surface can be formed, for example, in a slope shape that rises toward an upstream end of the developer main transport surface in the developer main transport direction. In this case, the developer sub-transport direction is a direction of rising on the developer sub-transport surface toward the upstream end of the developer main transport surface in the developer main transport direction.

  The image forming apparatus of the present invention having such a configuration operates as follows during image formation.

  The electrostatic latent image based on the potential distribution is formed on the latent image forming surface of the electrostatic latent image carrier. The latent image forming surface on which the electrostatic latent image is formed moves along the sub-scanning direction.

  On the other hand, a predetermined traveling wave voltage is applied to the plurality of first transport electrodes arranged along the sub-scanning direction. Thereby, a predetermined electric field is formed on the developer main transport surface of the developer transport body. This electric field is formed as a traveling-wave electric field that travels in the developer main transport direction along the sub-scanning direction.

  In addition, a predetermined traveling wave voltage is applied to the plurality of second transport electrodes arranged along the sub-scanning direction. As a result, a predetermined electric field is formed on the developer sub-transport surface. This electric field is formed as a traveling-wave electric field that travels in the developer sub-transport direction along the sub-scanning direction.

  The developer accommodated in the developer accommodating casing is transported in the developer sub-transport direction by the traveling wave electric field described above on the developer sub-transport surface. The developer transport on the developer sub-transport surface starts from a predetermined developer transport start area.

  This developer conveyance start area is an area in the vicinity of a position where the uppermost end portion of the developer reservoir in the developer containing casing and the developer sub-conveying surface are closest to each other. Here, the developer reservoir means an aggregate of the developer stored in the space at the bottom of the developer containing casing.

  The developer is transported in the developer main transport direction on the developer main transport surface by the traveling wave electric field described above. The developer is supplied to a position (development position) where the latent image forming surface parallel to each other and the developer main transport surface face each other.

  Thereafter, the developer that has passed through the development position described above returns to the developer pool while being transported in the developer main transport direction on the developer main transport surface.

  Thus, the developer supply device supplies the developer in a charged state to the latent image forming surface on which the electrostatic latent image is formed. Thereby, the electrostatic latent image is developed (visualized) by the developer.

  In the image forming apparatus having such a configuration, an angle between the upper surface of the developer reservoir and the developer sub-transport surface (hereinafter referred to as “developer contact angle”) in the developer transport start region is substantially constant. Can be.

  When the developer contact angle fluctuates as the developer storage amount (storage amount) in the developer storage casing changes, the developer transport start area reaches the developer sub-transport surface. The supply state of the developer and the transport state of the developer from the developer transport start area to the downstream side in the developer sub transport direction vary.

  On the other hand, according to the present invention, as described above, the change in the developer contact angle due to the change in the developer storage amount (storage amount) in the developer storage casing is suppressed as much as possible. Is done.

  Thus, the developer supply state to the developer sub-transport surface in the developer transport start area, and the developer transport from the developer transport start area to the downstream side in the developer sub-transport direction. The state can be stabilized.

  Therefore, according to the image forming apparatus of the present invention, a change in image quality associated with a change in the developer storage amount (storage amount) can be suppressed as much as possible.

  The image forming apparatus may be configured as follows: the second transport electrode is provided along the developer sub-transport surface and the developer auxiliary transport surface. The downstream end of the developer sub-transport surface in the developer sub-transport direction is connected to the developer auxiliary transport surface. The plurality of second transport electrodes are configured to transport the developer toward a predetermined position.

  Here, the developer auxiliary transport surface includes at least a surface along the inner wall surface on the upstream side in the developer main transport direction from the opening of the top plate of the developer containing casing. Further, the predetermined position means that the upstream end of the developer main transport surface in the developer main transport direction and the developer sub-transport surface or the developer auxiliary transport surface are in the closest state. And facing each other.

  In this configuration, the developer is transported in the developer sub-transport direction on the developer sub-transport surface. Then, the developer reaches the developer auxiliary transport surface located downstream of the developer sub transport surface in the developer sub transport direction.

  Thereafter, the developer is transported to the predetermined position on the developer auxiliary transport surface. Thereby, the developer reaches the developer main transport surface. The developer is supplied to the development position by being conveyed in the developer main conveyance direction on the developer main conveyance surface.

  According to this configuration, the developer can be reliably transported from the developer sub-transport surface to the developer main transport surface. Therefore, the supply state of the developer to the developer main transport surface and the development position can be further stabilized.

  The image forming apparatus may further include a developer vibration unit.

  The developer oscillating unit is configured to vibrate the developer (the developer reservoir) stored (stored) in the developer storage casing. It is preferable that the developer vibration unit is configured to vibrate the developer at least in the developer conveyance start region.

  In this configuration, the developer stored in the developer accommodating casing (before being transported on the developer main transport surface) is vibrated by the developer vibration unit. Thereby, good fluidity is imparted to the developer (preferably in the developer conveyance start region).

  According to this configuration, the amount of the developer supplied from the developer pool (the developer transport start area) to the developer sub-transport surface is as much as possible in the main scanning direction and the sub-scanning direction. Can be homogenized.

  As a result, the transport amount of the developer from the developer reservoir (the developer transport start region) to the downstream side in the developer sub transport direction is as small as possible in the main scanning direction and the sub scanning direction. Can be homogenized.

  In addition, it is possible to suppress as much as possible stress such as a large cohesive force and shearing force applied to the developer in the developer pool.

  Therefore, according to such a configuration, the occurrence of density unevenness can be effectively suppressed and a good image can be formed.

  The developer oscillating unit may include a vibrator and a vibrator driving unit.

  Here, the vibrator is disposed in the developer accommodating casing so as to be separated from the developer sub-transport surface. The vibrator is swingably supported by the developer containing casing.

  The vibrator driving unit is configured to vibrate the vibrator from the outside of the developer containing casing. The vibrator driving unit is disposed outside the developer containing casing.

  In this configuration, the vibrator vibrates in a state where the vibrator is separated from the developer containing casing and the developer transport body. Therefore, vibration generated in the vibrator is not directly transmitted to the developer containing casing and the developer transport body.

  Therefore, according to this configuration, the predetermined positional relationship between the latent image forming surface of the electrostatic latent image carrier and the developer main transport surface of the developer transport body is caused by vibration of the vibrator. The fluctuation can be suppressed as much as possible.

  Thereby, while suppressing the adverse effect on the development of the electrostatic latent image as much as possible, the developer is fluidized well to transport the developer on the developer main transport surface and the developer sub-transport surface. The state can be made uniform.

  (2) An image forming apparatus of the present invention includes an electrostatic latent image carrier and a developer supply device. The electrostatic latent image carrier is configured in the same manner as described in (1) above.

  The developer supply device is disposed to face the electrostatic latent image carrier. The developer supply device is configured to supply the developer to the latent image forming surface in a charged state.

  Specifically, the developer supply device includes a developer containing casing, a developer transport body, a plurality of first transport electrodes, and a plurality of second transport electrodes.

  The developer accommodating casing is a box-shaped member and is configured to accommodate the developer. The developer containing casing includes a top plate and a bottom plate provided to face the top plate. An opening is formed in the developer containing casing at a position of the top plate facing the electrostatic latent image carrier.

  The developer transport body has a developer main transport surface parallel to the main scanning direction. The developer transport body is disposed in the developer containing casing so that the developer main transport surface faces the electrostatic latent image carrier with the opening in the top plate interposed therebetween.

  The plurality of first transport electrodes are provided along the developer main transport surface so as to face the latent image forming surface. These first transport electrodes are arranged along the sub-scanning direction. The first transport electrodes are configured to transport the developer in a predetermined developer main transport direction on the developer main transport surface by applying a traveling wave voltage. Yes.

  The plurality of second transport electrodes are provided along a sloped developer sub-transport surface. These second transport electrodes are arranged along the sub-scanning direction. The second transport electrodes are configured to transport the developer in a predetermined developer sub-transport direction on the developer sub-transport surface by applying a traveling wave voltage. Yes.

  Here, in the image forming apparatus of the present invention, the developer sub-transport surface is a surface along the upper surface of the bottom plate in the developer containing casing, and an angle formed with a horizontal plane is always 30 degrees or less. It is formed as follows.

  The developer sub-transport surface can be formed, for example, in the shape of a slope that rises toward the upstream end of the developer main transport surface in the developer main transport direction. In this case, the developer sub-transport direction is a direction of rising on the developer sub-transport surface toward the upstream end of the developer main transport surface in the developer main transport direction.

  The image forming apparatus of the present invention having such a configuration operates as follows during image formation.

  The electrostatic latent image is formed on the latent image forming surface. The latent image forming surface on which the electrostatic latent image is formed moves along the sub-scanning direction.

  On the other hand, a predetermined traveling wave voltage is applied to the plurality of first transport electrodes arranged along the sub-scanning direction. As a result, a traveling-wave electric field that travels in the developer main transport direction is formed on the developer main transport surface of the developer transport body.

  In addition, a predetermined traveling wave voltage is applied to the plurality of second transport electrodes arranged along the sub-scanning direction. As a result, a traveling wave electric field traveling in the developer sub-transport direction is formed on the developer sub-transport surface.

  The developer housed in the developer housing casing starts from a predetermined developer transport start region and starts in the developer sub-transport direction on the developer sub-transport surface by the traveling wave electric field described above. Be transported.

  Here, the developer conveyance start area is an area in the vicinity of the position where the uppermost end of the developer reservoir in the developer containing casing and the developer sub-conveying surface are closest to each other. The developer reservoir is an aggregate of the developer stored in a space at the bottom of the developer containing casing.

  Then, the developer is transported in the developer main transport direction on the developer main transport surface by the traveling wave electric field described above. The developer is supplied to a position (development position) where the latent image forming surface parallel to each other and the developer main transport surface face each other.

  Thereafter, the developer that has passed through the development position described above returns to the developer pool while being transported in the developer main transport direction on the developer main transport surface.

  In the image forming apparatus having such a configuration, the angle between the upper surface of the developer reservoir and the developer sub-transport surface (hereinafter referred to as “developer contact angle”) in the developer transport start region is always 30. Less than or equal to degrees. Therefore, the influence of the traveling wave electric field described above can be exerted on most of the developer in the developer conveyance start region.

  Therefore, according to this configuration, the amount of the developer supplied to the developer sub-transport surface in the developer transport start region can be increased as much as possible. As a result, the developer transport amount from the developer transport start area to the downstream side in the developer sub-transport direction and the developer transport amount on the developer main transport surface are ensured as much as possible. Can be done.

  Therefore, according to the image forming apparatus of the present invention, occurrence of a change in image quality can be suppressed as much as possible.

  The image forming apparatus may be configured as follows: the second transport electrode is provided along the developer sub-transport surface and the developer auxiliary transport surface. The downstream end of the developer sub-transport surface in the developer sub-transport direction is connected to the developer auxiliary transport surface. The plurality of second transport electrodes are configured to transport the developer toward a predetermined position.

  Here, the developer auxiliary transport surface includes at least a surface along the inner wall surface on the upstream side in the developer main transport direction from the opening of the top plate of the developer containing casing. Further, the predetermined position means that the upstream end of the developer main transport surface in the developer main transport direction and the developer sub-transport surface or the developer auxiliary transport surface are in the closest state. And facing each other.

  According to this configuration, the developer can be reliably transported from the developer sub-transport surface to the developer main transport surface by mediating the developer auxiliary transport surface. Therefore, the supply state of the developer to the developer main transport surface and the development position can be further stabilized.

  The image forming apparatus may further include a developer vibration unit. The developer exciting unit is configured to be able to vibrate the developer (stored in the developer) housed (stored) in the developer housing casing. Here, it is preferable that the developer vibration unit is configured to vibrate the developer at least in the developer conveyance start region.

  In this configuration, the developer before being transported on the developer main transport surface, which is stored in the developer accommodating casing, is vibrated by the developer vibration unit. Thereby, good fluidity is imparted to the developer (preferably in the developer conveyance start region).

  According to this configuration, the amount of the developer supplied from the developer pool (the developer transport start area) to the developer sub-transport surface, and the developer pool (the developer transport start area) The transport amount of the developer to the downstream side in the developer sub transport direction can be made as uniform as possible in the main scanning direction and the sub scanning direction. In addition, it is possible to suppress as much as possible stress such as a large cohesive force and shearing force applied to the developer in the developer pool. Therefore, the occurrence of density unevenness can be effectively suppressed and a good image can be formed.

  The developer oscillating unit may include a vibrator and a vibrator driving unit.

  Here, the vibrator is disposed in the developer accommodating casing so as to be separated from the developer sub-transport surface. The vibrator is swingably supported by the developer containing casing.

  The vibrator driving unit is configured to vibrate the vibrator from the outside of the developer containing casing. The vibrator driving unit is disposed outside the developer containing casing.

  In this configuration, the vibrating vibrator is separated from the developer containing casing and the developer transport body. Therefore, it is possible that the predetermined positional relationship between the latent image forming surface of the electrostatic latent image carrier and the developer main transport surface of the developer transport body varies due to vibration of the vibrator. It can be suppressed as much as possible.

  Therefore, according to such a configuration, while suppressing the adverse effect on the development of the electrostatic latent image as much as possible, the developer is fluidized well so that the developer main transport surface and the developer sub-transport surface The conveyance state of the developer can be made uniform.

  (3) The developer supply apparatus of the present invention is configured to be able to supply a developer along a predetermined developer transport direction in a charged state with respect to the developer carrying surface of the developer carrying body. . Here, the developer carrying surface is a surface parallel to a predetermined main scanning direction and capable of carrying the developer.

  The developer carrying member has the developer carrying surface and is configured so that the developer carrying surface can move along a sub-scanning direction orthogonal to the main scanning direction.

  As the developer carrying member, for example, an electrostatic latent image carrying member having a latent image forming surface configured to be able to form an electrostatic latent image by potential distribution can be used.

  Alternatively, as the developer carrying member, for example, a recording medium (paper) conveyed along the sub-scanning direction can be used.

  Alternatively, as the developer carrier, for example, the developer can be transferred onto the recording medium or the electrostatic latent image carrier by facing the recording medium or the electrostatic latent image carrier. A roller, sleeve, or belt-shaped member (developing roller, developing sleeve, intermediate transfer belt, etc.) constructed and arranged can be used.

  The developer supply apparatus of the present invention includes a developer containing casing, a developer transport body, and a plurality of transport electrodes.

  The developer accommodating casing is a box-shaped member and is configured to accommodate the developer. The developer containing casing includes a top plate and a bottom plate provided to face the top plate. An opening is formed at a position of the top plate of the developer containing casing facing the developer carrier.

  The developer transport body has a developer main transport surface parallel to the main scanning direction. The developer transport body is disposed in the developer containing casing such that the developer main transport surface faces the developer carrying body with the opening in the top plate interposed therebetween.

  The plurality of first transport electrodes are provided along the developer main transport surface so as to face the developer carrying surface. These first transport electrodes are arranged along the sub-scanning direction. The first transport electrodes are configured to transport the developer in a predetermined developer main transport direction on the developer main transport surface by applying a traveling wave voltage. Yes.

  The plurality of second transport electrodes are provided along a sloped developer sub-transport surface and along the bottom plate of the developer containing casing. These second transport electrodes are arranged along the sub-scanning direction. The second transport electrodes are configured to transport the developer in a predetermined developer sub-transport direction on the developer sub-transport surface by applying a traveling wave voltage. Yes.

  Here, in the developer supply device of the present invention, the developer sub-transport surface is formed in a planar shape intersecting the horizontal plane so that an angle formed with the horizontal plane is constant. For example, the developer sub-transport surface can be formed such that the angle formed with the horizontal plane is always 30 degrees or less.

  In addition, the developer sub-transport surface can be formed, for example, in a slope shape that rises toward an upstream end of the developer main transport surface in the developer main transport direction. In this case, the developer sub-transport direction is a direction of rising on the developer sub-transport surface toward the upstream end of the developer main transport surface in the developer main transport direction.

  The developer supply apparatus of the present invention having such a configuration operates as follows.

  The developer carrying surface of the developer carrying body moves along the sub-scanning direction.

  On the other hand, a predetermined traveling-wave voltage is applied to the plurality of first transport electrodes and the plurality of second transport electrodes arranged along the sub-scanning direction.

  As a result, a traveling-wave electric field that travels in the developer main transport direction along the sub-scanning direction is formed on the developer main transport surface of the developer transport body. In addition, a traveling-wave electric field that travels in the developer sub-transport direction along the sub-scanning direction is formed on the developer sub-transport surface.

  The developer housed in the developer housing casing starts from a predetermined developer transport start region in the developer reservoir, and the developer is generated by the traveling wave electric field on the developer sub-transport surface. It is transported in the sub transport direction.

  Here, the developer reservoir is an aggregate of the developer stored in the space at the bottom of the developer containing casing. The developer transport start area is an area in the vicinity of a position where the uppermost end of the developer reservoir in the developer containing casing and the developer sub-transport surface are closest to each other. )

  In such a configuration, the angle between the upper surface of the developer reservoir and the developer sub-transport surface (hereinafter referred to as “developer contact angle”) in the developer transport start region can be substantially constant.

  That is, in such a configuration, fluctuations in the developer contact angle due to fluctuations in the developer storage amount (storage amount) in the developer storage casing are suppressed as much as possible.

  Thus, the developer supply state to the developer sub-transport surface in the developer transport start area, and the developer transport from the developer transport start area to the downstream side in the developer sub-transport direction. The state can be stabilized.

  Thereafter, the developer is transported in the developer main transport direction on the developer main transport surface by the traveling wave electric field described above. The developer is supplied to a position (developer carrying position) where the developer carrying surface and the developer main transport surface parallel to each other face each other. Thereby, the developer is carried on the developer carrying surface at the developer carrying position.

  The developer having passed through the developer carrying position returns to the developer reservoir while being transported in the developer main transport direction on the developer main transport surface.

  As described above, according to the developer supply apparatus of the present invention, the change in the developer transport amount accompanying the change in the developer storage amount (reserved amount) can be suppressed as much as possible.

  The developer supply device may be configured as follows: the second transport electrode is provided along the developer sub-transport surface and the developer auxiliary transport surface. The downstream end of the developer sub-transport surface in the developer sub-transport direction is connected to the developer auxiliary transport surface. The plurality of second transport electrodes are configured to transport the developer toward a predetermined position.

  Here, the developer auxiliary transport surface includes at least a surface along the inner wall surface on the upstream side in the developer main transport direction from the opening of the top plate of the developer containing casing. The predetermined position is a position where the end portion of the developer main transport surface faces the developer sub-transport surface or the developer auxiliary transport surface in the closest state.

  In such a configuration, when the developer is transported in the developer sub-transport direction on the developer sub-transport surface, the developer reaches the developer auxiliary transport surface. Thereafter, the developer is transported to the predetermined position on the developer auxiliary transport surface.

  Thereby, the developer reaches the developer main transport surface. Then, the developer is supplied to the developer carrying position by being conveyed in the developer main conveyance direction on the developer main conveyance surface.

  According to this configuration, the developer can be reliably transported from the developer sub-transport surface to the developer main transport surface. Therefore, the supply state of the developer to the developer main transport surface and the developer carrying position can be further stabilized.

  The developer supply device may further include a developer vibration unit. Here, the developer exciting unit is configured to be able to vibrate the developer (the developer reservoir) accommodated (stored) in the developer accommodating casing. It is preferable that the developer vibration unit is configured to vibrate the developer at least in the developer conveyance start region.

  In such a configuration, the developer stored in the developer containing casing is vibrated by the developer vibration unit. Thereby, good fluidity is imparted to the developer.

  According to this configuration, the amount of the developer supplied from the developer pool (the developer transport start area) to the developer sub-transport surface is as much as possible in the main scanning direction and the sub-scanning direction. Can be homogenized. Thereby, the transport amount of the developer from the developer reservoir to the downstream side in the developer sub-transport direction can be made as uniform as possible.

  In addition, it is possible to suppress as much as possible stress such as a large cohesive force and shearing force applied to the developer in the developer pool.

  The developer oscillating unit may include a vibrator and a vibrator driving unit.

  Here, the vibrator is disposed in the developer accommodating casing so as to be separated from the developer sub-transport surface. The vibrator is swingably supported by the developer containing casing.

  The vibrator driving unit is configured to vibrate the vibrator from the outside of the developer containing casing. The vibrator driving unit is disposed outside the developer containing casing.

  In this configuration, the vibrator vibrates in a state where the vibrator is separated from the developer containing casing and the developer transport body. Therefore, vibration generated in the vibrator is not directly transmitted to the developer containing casing and the developer transport body.

Therefore, according to this configuration, the predetermined positional relationship between the developer carrying surface of the developer carrying body and the developer main carrying surface of the developer carrying body varies due to vibration of the vibrator. Can be suppressed as much as possible.
(4) The developer supply device of the present invention is configured so that the developer can be supplied along a predetermined developer transport direction in a charged state with respect to the developer carrying surface of the developer carrying body. . Here, the developer carrying surface is a surface parallel to a predetermined main scanning direction and capable of carrying the developer.

  The developer carrying member has the developer carrying surface and is configured so that the developer carrying surface can move along a sub-scanning direction orthogonal to the main scanning direction.

  As the developer carrying member, for example, an electrostatic latent image carrying member having a latent image forming surface configured to be able to form an electrostatic latent image by potential distribution can be used.

  Alternatively, as the developer carrying member, for example, a recording medium (paper) conveyed along the sub-scanning direction can be used.

  Alternatively, as the developer carrier, for example, the developer can be transferred onto the recording medium or the electrostatic latent image carrier by facing the recording medium or the electrostatic latent image carrier. A roller, sleeve, or belt-shaped member (developing roller, developing sleeve, intermediate transfer belt, etc.) constructed and arranged can be used.

  The developer supply apparatus of the present invention includes a developer containing casing, a developer transport body, and a plurality of transport electrodes.

  The developer accommodating casing is a box-shaped member and is configured to accommodate the developer. The developer containing casing includes a top plate and a bottom plate provided to face the top plate. An opening is formed at a position of the top plate of the developer containing casing facing the developer carrier.

  The developer transport body has a developer main transport surface parallel to the main scanning direction. The developer transport body is disposed in the developer containing casing such that the developer main transport surface faces the developer carrying body with the opening in the top plate interposed therebetween.

  The plurality of first transport electrodes are provided along the developer main transport surface so as to face the developer carrying surface. These first transport electrodes are arranged along the sub-scanning direction. The first transport electrodes are configured to transport the developer in a predetermined developer main transport direction on the developer main transport surface by applying a traveling wave voltage. Yes.

  The plurality of second transport electrodes are provided along a sloped developer sub-transport surface. Here, the developer sub-transport surface is a surface along the upper surface of the bottom plate in the developer containing casing, and is formed so that an angle formed with a horizontal plane is always 30 degrees or less.

  These second transport electrodes are arranged along the sub-scanning direction. The second transport electrodes are configured to transport the developer in a predetermined developer sub-transport direction on the developer sub-transport surface by applying a traveling wave voltage. Yes.

  The developer sub-transport surface can be formed, for example, in the shape of a slope that rises toward the upstream end of the developer main transport surface in the developer main transport direction. In this case, the developer sub-transport direction is a direction of rising on the developer sub-transport surface toward the upstream end of the developer main transport surface in the developer main transport direction.

  The developer supply apparatus of the present invention having such a configuration operates as follows.

  The developer carrying surface of the developer carrying body moves along the sub-scanning direction.

  On the other hand, a predetermined traveling wave voltage is applied to the plurality of first transport electrodes. As a result, a traveling-wave electric field that travels in the developer main transport direction is formed on the developer main transport surface of the developer transport body.

  A predetermined traveling wave voltage is applied to the plurality of second transport electrodes. As a result, a traveling wave electric field traveling in the developer sub-transport direction is formed on the developer sub-transport surface.

  The developer in the developer containing casing is transported in the developer sub-transport direction on the developer sub-transport surface by the above-described traveling wave electric field, starting from a predetermined developer transport start region. .

  Here, the developer conveyance start area is an area in the vicinity of the position where the uppermost end of the developer reservoir in the developer containing casing and the developer sub-conveying surface are closest to each other. The developer reservoir is an aggregate of the developer stored in a space at the bottom of the developer containing casing.

  The developer is transported in the developer main transport direction on the developer main transport surface by the traveling wave electric field described above. The developer is supplied to a position (developer carrying position) where the developer carrying surface and the developer main transport surface parallel to each other face each other. Thereafter, the developer passing through the developer carrying position returns to the developer pool while being transported in the developer main transport direction on the developer main transport surface.

  In such a configuration, the angle between the upper surface of the developer reservoir and the developer sub-transport surface (hereinafter referred to as “developer contact angle”) in the developer transport start region is always 30 degrees or less. . Therefore, the influence of the traveling wave electric field described above can be exerted on most of the developer in the developer conveyance start region.

  Thereby, the supply amount of the developer to the developer sub-transport surface in the developer transport start region can be increased as much as possible. Therefore, the developer transport amount from the developer transport start region to the downstream side in the developer sub-transport direction and the developer transport amount on the developer main transport surface are ensured as much as possible. obtain.

  Therefore, according to the developer supply apparatus of the present invention, the occurrence of a shortage of the developer transport amount can be suppressed as much as possible.

  The developer supply device may be configured as follows: the second transport electrode is provided along the developer sub-transport surface and the developer auxiliary transport surface. The downstream end of the developer sub-transport surface in the developer sub-transport direction is connected to the developer auxiliary transport surface. The plurality of second transport electrodes are configured to transport the developer toward a predetermined position.

  Here, the developer auxiliary transport surface includes at least a surface along the inner wall surface on the upstream side in the developer main transport direction from the opening of the top plate of the developer containing casing. The predetermined position is a position where the end portion of the developer main transport surface faces the developer sub-transport surface or the developer auxiliary transport surface in the closest state.

  In such a configuration, when the developer is transported in the developer sub-transport direction on the developer sub-transport surface, the developer reaches the developer auxiliary transport surface. Thereafter, the developer is transported to the predetermined position on the developer auxiliary transport surface.

  Thereby, the developer reaches the developer main transport surface. Then, the developer is supplied to the developer carrying position by being conveyed in the developer main conveyance direction on the developer main conveyance surface.

  According to this configuration, the developer can be reliably transported from the developer sub-transport surface to the developer main transport surface. Therefore, the supply state of the developer to the developer main transport surface and the developer carrying position can be further stabilized.

  The developer supply device may further include a developer vibration unit. Here, the developer exciting unit is configured to be able to vibrate the developer (the developer reservoir) accommodated (stored) in the developer accommodating casing. It is preferable that the developer vibration unit is configured to vibrate the developer at least in the developer conveyance start region.

  In such a configuration, the developer stored in the developer containing casing is vibrated by the developer oscillating unit, so that good fluidity is imparted to the developer. At this time, it is possible to suppress as much as possible that stress such as a large cohesive force or shear force is applied to the developer in the developer pool.

  According to this configuration, the amount of the developer supplied to the developer sub-transport surface can be made as uniform as possible in the main scanning direction and the sub-scanning direction. Thereby, the transport amount of the developer from the developer reservoir to the downstream side in the developer sub-transport direction can be made as uniform as possible.

  The developer oscillating unit may include a vibrator and a vibrator driving unit.

  Here, the vibrator is disposed in the developer accommodating casing so as to be separated from the developer sub-transport surface. The vibrator is swingably supported by the developer containing casing.

  The vibrator driving unit is configured to vibrate the vibrator from the outside of the developer containing casing. The vibrator driving unit is disposed outside the developer containing casing.

  In this configuration, the vibrator vibrates in a state where the vibrator is separated from the developer containing casing and the developer transport body. Therefore, it is possible that the predetermined positional relationship between the developer carrying surface of the developer carrying body and the developer main carrying surface of the developer carrying body varies due to vibration of the vibrator. Can be suppressed.

  Hereinafter, embodiments of the present invention (embodiments that the applicant considers best at the time of filing of the present application) will be described with reference to the drawings.

<Overall configuration of laser printer>
FIG. 1 is a side sectional view showing a schematic configuration of a laser printer 100 to which an embodiment of the present invention is applied.

  The laser printer 100 according to the present embodiment uses sheet-like paper P as an image formation target or a recording medium. The laser printer 100 according to the present embodiment is configured to be able to form a single color (for example, black) image on the paper P.

  Here, in FIG. 1, the sheet conveyance path PP that is the conveyance path of the sheet P is indicated by a two-dot chain line. The tangential direction of the paper transport path PP is referred to as a paper transport direction.

  Further, the x-axis direction in the figure is referred to as the front-rear direction. One end side (right side in the figure) of the laser printer 100 in the front-rear direction is referred to as “front” side. On the other hand, the other end side (left side in the figure) opposite to the one end side of the laser printer 100 is referred to as a “rear” side.

  Furthermore, a height direction (y-axis direction in the drawing) of the laser printer 100, the paper conveyance direction, and a direction orthogonal to the front-rear direction are defined as a paper width direction (z-axis direction in the drawing).

<< Main body >>
Referring to FIG. 1, a laser printer 100 as an image forming apparatus of the present invention includes a main body casing 112. The main body casing 112 is a member constituting an outer cover of the laser printer 100, and is integrally formed of a synthetic resin plate.

  A paper ejection port 112 a composed of a slit-like through hole is formed on the front side of the upper portion of the main body casing 112.

  A paper discharge tray (catch tray) 114 is mounted on the front side of the upper portion of the main body casing 112 and at a position corresponding to the paper discharge port 112a. The paper discharge tray 114 is configured to receive the image-formed paper P discharged from the paper discharge port 112a.

<< Electrostatic latent image forming section >>
An electrostatic latent image forming unit 120 is accommodated in the main body casing 112. The electrostatic latent image forming unit 120 includes a photosensitive drum 121 as an electrostatic latent image carrier and a developer carrier of the present invention.

  The photosensitive drum 121 is a substantially cylindrical member. The rotation center axis of the photoconductive drum 121 is arranged to be parallel to the paper width direction. The photosensitive drum 121 is configured to be driven to rotate clockwise in the drawing.

  Specifically, the photosensitive drum 121 includes a drum main body 121a and a photosensitive layer 121b.

  The drum body 121a is made of a metal tube such as an aluminum alloy. The photoreceptor layer 121b is formed on the outer periphery of the drum body 121a.

  The photoreceptor layer 121b is composed of a positively chargeable photoconductive layer. In other words, the photoreceptor layer 121b is made of a material that exhibits electrical conductivity using holes as carriers when irradiated with light in a predetermined wavelength band.

  The photosensitive drum 121 has a latent image forming surface and an image carrying surface 121b1 as a developer carrying surface of the present invention.

  The image carrying surface 121b1 is constituted by the peripheral surface of the photoreceptor layer 121b. The image carrying surface 121b1 is formed to be parallel to the paper width direction and the main scanning direction described later. The image carrying surface 121b1 is configured such that an electrostatic latent image can be formed by a potential distribution.

  The photosensitive drum 121 is configured such that the image bearing surface 121b1 can move along a sub-scanning direction (to be described later) (a direction orthogonal to a main scanning direction to be described later).

  The electrostatic latent image forming unit 120 includes a scanner unit 122 and a charger 123.

  The scanner unit 122 is configured to generate a laser beam LB. The laser beam LB has a wavelength band included in the predetermined wavelength band in which the above-described photoreceptor layer 121b exhibits electrical conductivity, and is modulated based on image information.

  The scanner unit 122 is configured to scan the laser beam LB along the main scanning direction. Here, the main scanning direction is a direction (z-axis direction in the drawing) parallel to the paper width direction.

  In other words, the scanner unit 122 is configured and arranged so as to irradiate the image carrying surface 121b1 while scanning the laser beam LB described above at the predetermined scan position SP along the main scanning direction. .

  The charger 123 is disposed upstream of the scan position SP in the moving direction of the image carrying surface 121b1 (the rotation direction of the photosensitive drum 121). The charger 123 is configured and arranged so that the image carrying surface 121b1 upstream in the direction from the scan position SP can be uniformly positively charged.

  The electrostatic latent image forming unit 120 irradiates the image carrying surface 121b1 uniformly positively charged by the charger 123 with the laser beam LB by the scanner unit 122, thereby static electricity due to the potential distribution (charge distribution). An electrostatic latent image can be formed on the image bearing surface 121b1.

  The electrostatic latent image forming unit 120 is configured to be able to move the image carrying surface 121b1 on which the electrostatic latent image is formed along the sub-scanning direction.

  Here, the “sub-scanning direction” is an arbitrary direction orthogonal to the main scanning direction. Usually, the sub-scanning direction is a direction intersecting the vertical line. Typically, the sub-scanning direction may be a direction along the front-rear direction (x-axis direction in the drawing) of the laser printer 100.

<< Developing device >>
A developing device 130 as a developer supply device of the present invention is accommodated in the main body casing 112. The developing device 130 is disposed so as to face the photosensitive drum 121 at the developing position DP (developer carrying position).

  Inside the developing device 130, a toner storage area 130a is formed. The toner storage area 130a is a space in which the toner T, which is a fine particle dry developer (powder developer), can be stored (stored).

  When the laser printer 100 is not operating, the toner T is stored at the bottom of the toner storage area 130a. The aggregate of the toner T stored at the bottom of the toner storage area 130a is hereinafter referred to as “toner reservoir TP”.

  The developing device 130 is configured to be able to transport the toner T along the toner main transport direction TTD1 and the toner sub-transport direction TTD2, as indicated by arrows in the drawing.

  Here, the toner main transport direction TTD1 as the developer main transport direction of the present invention is a transport direction of the toner T on a toner main transport surface 133a described later.

  The toner main transport direction TTD1 is set to be substantially parallel to the sub-scanning direction (x-axis direction in the figure) when viewed from above (when viewed in a direction parallel to the y-axis direction in the figure). (Note that the toner main transport direction TTD1 may be partially parallel to the height direction (y-axis direction in the figure)).

  Further, the toner sub-transport direction TTD2 as the developer sub-transport direction of the present invention is a transport direction of the toner T on a toner sub-transport surface 135a described later.

  The toner sub-transport direction TTD2 is also set to be substantially parallel to the sub-scanning direction (x-axis direction in the figure) when viewed from above (note that the toner sub-transport direction TTD2 is also partially , And can be parallel to the height direction (y-axis direction in the figure).

  The developing device 130 is configured to convey the toner T while circulating it along a circulation conveyance path formed in a substantially oval (oval) shape in a side sectional view. That is, the toner main transport direction TTD1 and the toner sub-transport direction TTD2 are tangential directions at arbitrary points on the above-described circulation transport path in a side sectional view.

  The developing device 130 is configured and arranged as follows so that the toner T can be supplied to the image carrying surface 121b1 on which the electrostatic latent image is formed in the vicinity of the developing position DP. Yes.

  Note that the toner T in this embodiment is used for non-magnetic one-component development in an electrophotographic system.

  FIG. 2 is an enlarged side sectional view of the electrostatic latent image forming unit 120 and the developing device 130 shown in FIG.

  Referring to FIGS. 1 and 2, the developing device 130 is disposed below the photosensitive drum 121. The developing device 130 is provided so as to face the image carrying surface 121b1 on the downstream side in the moving direction of the image carrying surface 121b1 with respect to the scan position SP.

<<< Development casing >>>
Referring to FIGS. 1 and 2, a developing casing 131 as a developer containing casing of the present invention is a box-like member and is configured to store toner T. That is, the above-described toner reservoir TP is accommodated at the bottom of the toner accommodating region 130a formed in the developing casing 131.

  The casing upper surface cover 131a as a top plate in the developer containing casing of the present invention is formed in a substantially J shape in a side sectional view. The developing portion facing plate 131a1, which is the rear portion of the casing upper surface cover 131a, is thinner than the other portions.

  The developing unit facing plate 131a1 includes a flat plate portion located below the photosensitive drum 121 and a semi-cylindrical portion connected to the rear end of the flat plate portion.

  A developing opening 131a2 as an opening of the present invention is formed in the flat plate portion of the developing portion facing plate 131a1. The development opening 131a2 is provided so as to surround the development position DP at a position facing the image carrying surface 121b1 on the development unit facing plate 131a1.

  A casing bottom plate 131b as a bottom plate in the developer containing casing of the present invention is provided so as to face the casing upper surface cover 131a. The casing bottom plate 131b is composed of a flat plate-like member having the same thickness as the developing unit facing plate 131a1.

  The casing bottom plate 131b is provided in an inclined state so that the angle formed with the horizontal plane is constant and 30 degrees or less. That is, the casing bottom plate 131b is arranged so as to form a gentle slope such that the upper surface of the casing bottom plate 131b in the drawing rises from the front side toward the rear side.

  The rear end portion of the casing bottom plate 131b is connected to the lower end of the above-described semicylindrical portion of the casing upper surface cover 131a. That is, the casing bottom plate 131b and the casing upper surface cover 131a are integrally formed so as to be smoothly connected at the rear end of the developing casing 131.

  Both ends of the casing top cover 131a and the casing bottom plate 131b in the sheet width direction are closed by a pair of casing side plates 131c.

  Further, the front ends of the casing top cover 131a, the casing bottom plate 131b, and the pair of casing side plates 131c are closed by a casing front closing plate 131d.

  That is, the above-described toner accommodation region 130a is configured by a space surrounded by the casing top cover 131a, the casing bottom plate 131b, the pair of casing side plates 131c, and the casing front closing plate 131d.

<<< Toner Electric Field Carrier >>>
Referring to FIG. 2, a toner electric field transport body 132 as a developer transport body of the present invention is accommodated inside the developing casing 131. That is, the toner electric field transport body 132 is covered with the developing casing 131.

  The toner electric field carrier 132 is disposed on the rear side in the space inside the developing casing 131 so as to face the image carrying surface 121b1 with the developing opening 131a2 interposed therebetween. That is, the toner electric field transport body 132 is provided so that the photosensitive drum 121 and the toner electric field transport body 132 (the above-described toner main transport surface 133a) face each other with the development opening 131a2 interposed therebetween.

  Both ends of the toner electric field transport body 132 are supported by a pair of casing side plates 131c so as to float from the casing bottom plate 131b while facing the developing portion facing plate 131a1 with a predetermined gap.

<<<<< Carrying wiring board >>>>
FIG. 3 is an enlarged side cross-sectional view of a portion near the developing opening 131a2 in the toner electric field transport body 132 shown in FIG.

  Referring to FIGS. 2 and 3, the toner electric field transport body 132 includes a transport wiring board 133. The transport wiring substrate 133 is disposed so as to face the image carrying surface 121b1 with the development opening 131a2 interposed therebetween.

  The toner main transport surface 133a, which is the upper surface of the transport wiring board 133 in the figure, is formed in an inverted U shape when viewed from the side. That is, the rear end of the toner main transport surface 133a is formed to bend downward along the casing upper surface cover 131a of the developing casing 131.

  Further, the front end portion of the toner main transport surface 133a has the same shape as the rear end portion and is formed to be bent downward. A portion of the toner main transport surface 133a between the above-described both end portions is formed in a substantially flat shape.

  The toner main transport surface 133a as the developer main transport surface of the present invention is formed in parallel with the main scanning direction (z direction in the figure). Further, the toner main transport surface 133a is provided so as to face the image carrying surface 121b1 of the photosensitive drum 121. The toner main transport surface 133a and the image carrying surface 121b1 are closest to each other at the development position DP.

  Referring to FIG. 3, the transport wiring board 133 has the same configuration as the flexible printed wiring board. That is, the transport wiring board 133 includes a plurality of transport electrodes 133b as the first transport electrodes of the present invention.

  These transport electrodes 133b are arranged along the toner main transport surface 133a. That is, the transport electrode 133b is disposed in the vicinity of the main toner transport surface 133a.

  The transport electrode 133b is made of a copper foil having a thickness of about several tens of μm. The transport electrode 133b is formed as a linear wiring pattern having a longitudinal direction parallel to the main scanning direction (perpendicular to the sub-scanning direction).

  The plurality of transport electrodes 133b are arranged in parallel to each other. These transport electrodes 133b are arranged along the toner main transport direction TTD1 (along the sub-scanning direction).

  Each of the plurality of transport electrodes 133b arranged in the sub-scanning direction is connected to the same power supply circuit every third.

  That is, the transfer electrode 133b connected to the power supply circuit VA, the transfer electrode 133b connected to the power supply circuit VB, the transfer electrode 133b connected to the power supply circuit VC, the transfer electrode 133b connected to the power supply circuit VD, and the power supply circuit VA The transport electrodes 133b connected, the transport electrodes 133b connected to the power supply circuit VB are arranged in order along the sub-scanning direction.

  The transport wiring substrate 133 also includes a transport electrode support substrate 133c and a transport electrode coating layer 133d.

  The transport electrode support substrate 133c is a flexible film and is made of an insulating synthetic resin such as a polyimide resin. A transport electrode 133b is provided on the upper surface of the transport electrode support substrate 133c.

  A transport electrode coating layer 133d is provided on the upper surface of the transport electrode support substrate 133c where the transport electrodes 133b are formed. The transport electrode coating layer 133d is provided so as to cover the transport electrode 133b.

  The transport electrode coating layer 133d is provided so as to form the toner main transport surface 133a as a smooth surface by covering the transport electrode support substrate 133c and the transport electrode 133b.

  Referring to FIGS. 2 and 3, the toner electric field transport body 132 includes a transport substrate support member 134. The transport board support member 134 is provided so as to support the transport wiring board 133 from below.

  Referring to FIG. 2, the rear end of the transport substrate support member 134 is formed to be bent downward along the casing upper surface cover 131 a in the developing casing 131. The front end portion of the transport substrate support member 134 is also formed in the same shape as the rear end portion so as to be bent downward. The part between the above-mentioned both ends of the conveyance board | substrate support member 134 is formed in substantially flat form.

  That is, the transport substrate support member 134 is formed in an inverted U shape when viewed from the side. The transport wiring board 133 is supported by the transport board support member 134 in a state bent in an inverted U shape when viewed from the side.

  FIG. 4 is a graph showing waveforms of voltages generated by the power supply circuits VA to VD shown in FIG. As shown in FIG. 4, each of the power supply circuits VA to VD is configured to generate an AC voltage having substantially the same waveform.

  Here, the waveforms of the voltages generated by the power supply circuits VA to VD are different in phase by 90 °. That is, the power supply circuits VA to VD are controlled by the control unit 180 described later so that the phase of the voltage is delayed by 90 ° in order from the power supply circuit VA to the power supply circuit VD.

  2 and 3, in the toner electric field transport body 132, a transport voltage as shown in FIG. 4 is applied to each transport electrode 133b in the transport wiring board 133, and the toner main transport direction TTD1. Is generated so that the positively charged toner T can be transported in the toner main transport direction TTD1.

<<<<< Counter wiring board >>>>
Referring to FIGS. 1 and 2, as described above, a concave portion is formed on the inner side surface of the casing upper surface cover 131a at a position corresponding to the developing unit facing plate 131a1. A counter wiring board 135 is mounted on the inner wall surface of the developing casing 131 so as to be fitted into the recess.

  That is, the counter wiring substrate 135 is supported by the inner wall surface of the developing unit counter plate 131a1 so as to face the toner main transport surface 133a with a predetermined gap therebetween.

  In the present embodiment, the counter wiring board 135 is provided so as to correspond to almost the entire surface of the casing bottom plate 131b. That is, the counter wiring board 135 has the highest position of the casing bottom plate 131b (joining position between the lower end of the semi-cylindrical portion and the casing bottom plate 131b in the developing unit facing plate 131a1) and the lowest position (the front end of the casing bottom plate 131b in the figure). Part).

  As described above, the counter wiring substrate 135 is supported by the inner wall surface of the developing casing 131 in a state of being bent into a substantially U shape or a substantially V shape.

  The toner sub-transport surface 135a as the developer sub-transport surface of the present invention is a surface of the counter wiring substrate 135 and is formed by a portion corresponding to the casing bottom plate 131b. That is, the toner sub-transport surface 135a is a flat surface along the inner wall surface of the casing bottom plate 131b in the developing casing 131. Specifically, the toner sub-transport surface 135a is a plane parallel to the inner wall surface.

  Further, the toner sub-transport surface 135a is formed in a smooth slope shape whose angle with the horizontal plane is always 30 degrees or less. Further, the toner sub-transport surface 135a is formed in parallel with the main scanning direction (z direction in the drawing).

  The toner sub-transport surface 135a extends from the lower end portion of the casing front closing plate 131d to the rear end portion of the toner electric field transport body 132 (the upstream end portion of the toner main transport surface 133a in the toner main transport direction TTD1). It is formed in the shape of a slope that rises.

  In this case, the toner sub-transport direction TTD2 is a direction in which the toner sub-transport surface 135a rises toward the upstream end of the toner main transport surface 133a in the toner main transport direction TTD1.

  The toner auxiliary conveyance surface 135a 'as the developer auxiliary conveyance surface of the present invention is the surface of the counter wiring substrate 135 and is formed by a portion corresponding to the developing unit counter plate 131a1.

  That is, the toner auxiliary transport surface 135a ′ is the inner wall surface of the developing portion facing plate 131a1 on the upstream side (the above-described semi-cylindrical portion) and the downstream side (the above-described flat plate portion) in the toner main transport direction TTD1 with respect to the developing opening 131a2. It is formed by the surface along.

  Corresponds to the upstream end of the toner auxiliary transport surface 135a ′ in the toner sub-transport direction TTD2 (the end of the above-mentioned semi-cylindrical portion of the developing unit facing plate 131a1 farther from the developing opening 131a2 (lower end in the figure)). The end of the toner auxiliary transport surface 135a ′) is smoothly connected to the downstream end of the toner sub-transport surface 135a in the toner sub-transport direction TTD2 without a step.

  The toner auxiliary conveying surface 135a 'is also formed in parallel with the main scanning direction (z direction in the drawing).

  The counter wiring board 135 has the same configuration as the above-described transport wiring board 133.

  That is, referring to FIG. 3, the counter electrode 135b as the second transport electrode of the present invention is made of a copper foil having a thickness of about several tens of micrometers. The counter electrode 135b is formed as a linear wiring pattern having a longitudinal direction parallel to the main scanning direction (perpendicular to the sub-scanning direction).

  The plurality of counter electrodes 135b are arranged in parallel to each other. These counter electrodes 135b are arranged along a predetermined toner sub-transport direction TTD2 (along the sub-scanning direction). Each counter electrode 135b is connected to the same power supply circuit every third.

  The plurality of counter electrodes 135b are provided along the toner sub-transport surface 135a. That is, the counter electrode 135b is provided along the inner wall surface of the casing bottom plate 131b in the developing casing 131. Further, the plurality of counter electrodes 135b are provided along the toner auxiliary transport surface 135a '.

  The counter wiring substrate 135 includes a counter electrode support substrate 135c and a counter electrode coating layer 135d in addition to the counter electrode 135b described above.

  The counter electrode support substrate 135c is a flexible film and is made of an insulating synthetic resin such as a polyimide resin. A counter electrode 135b is provided on the lower surface of the counter electrode support substrate 135c in the figure.

  A counter electrode coating layer 135d is provided on the lower surface of the counter electrode support substrate 135c where the counter electrode 135b is formed. The counter electrode coating layer 135d is provided so as to cover the counter electrode 135b.

  The counter electrode coating layer 135d covers the counter electrode support substrate 135c and the counter electrode 135b, so that the toner sub-transport surface 135a is formed on a smooth slope whose angle with the horizontal plane is always 30 degrees or less. Is provided. The toner sub-transport surface 135a is formed in a gentle slope shape so as to rise from the front side toward the rear side.

  Similar to the above-described transport wiring substrate 133, the counter wiring substrate 135 is applied with a predetermined voltage to the plurality of counter electrodes 135b and generates a traveling-wave electric field along the toner sub-transport direction TTD2. The positively charged toner T can be transported in the toner sub-transport direction TTD2.

<<< Developer shaker >>>
Referring to FIG. 2, the developing device 130 in the present embodiment includes a vibrator 136 and a vibrator driving unit 137.

  The vibrator 136 and the vibrator driving unit 137 constitute the developer exciting unit of the present invention, and are provided in the vicinity of the casing bottom plate 131b. In other words, the vibrator 136 and the vibrator driving unit 137 are configured as follows so as to vibrate the toner reservoir TP (the toner T stored at the bottom of the toner containing region 130a in the developing casing 131). .

  FIG. 5 is a cross-sectional view of the developing casing 131 shown in FIG. 2 as seen from the front side (front side), showing an enlarged portion near the vibrator 136.

  Referring to FIG. 2, the vibrator 136 is a rod-shaped member, and is disposed along the paper width direction (z-axis direction in the drawing). The vibrator 136 is disposed in the developing casing 131 (toner accommodation region 130a) so as to be separated from the toner sub-transport surface 135a and to face the toner sub-transport surface 135a.

  That is, with reference to FIGS. 2 and 5, the pair of casing side plates 131 c are each provided with a casing through hole 131 c 1. The casing through hole 131c1 is formed to be slightly larger than the outer diameter of the vibrator 136. And the vibrator | oscillator 136 is arrange | positioned so that these pair of casing through-holes 131c1 may be penetrated.

  The vibrator driving unit 137 is disposed outside the developing casing 131 (toner accommodation area 130a). The vibrator driving unit 137 is configured as follows so that the vibrator 136 can be vibrated from the outside of the developing casing 131.

  Specifically, referring to FIG. 5, the vibrator driving unit 137 includes a vibration generating unit 137a and a vibration transmitting unit 137b.

  The vibration generating unit 137a includes a piezoelectric element or a vibrator that can generate vibration when energized.

  The vibration transmission unit 137b is a rod-shaped member made of metal, and is disposed so as to contact the vibrator 136 and the vibration generation unit 137a. The vibration transmitting unit 137b is configured to transmit the vibration generated by the vibration generating unit 137a to one end of the vibrator 136.

  A pair of elastic seals 138 are bonded to the inner surface of the casing side plate 131c (the surface facing the toner containing region 130a) at a position corresponding to the casing through hole 131c1. The elastic seal 138 is configured to suppress the leakage of the toner T (see FIG. 2) from the casing through hole 131c1 to the outside of the developing casing 131 and to support the vibrator 136.

  Specifically, the elastic seal 138 is a disk-shaped member and is made of synthetic rubber. A seal through-hole 138a is provided at a substantially central portion of the elastic seal 138. The seal through-hole 138a is formed slightly smaller than the outer diameter of the vibrator 136.

  The elastic seal 138 is disposed so that the central axis of the casing through hole 131c1 in the paper width direction (z-axis direction in the drawing) and the central axis of the seal through hole 138a in the paper width direction substantially coincide with each other. ing. That is, the vibrator 136 is swingably supported by the casing side plate 131c via the elastic seal 138.

<< Transfer section >>
Referring to FIG. 1 again, the transfer unit 140 faces the image bearing surface 121b1 at a position downstream of the photosensitive drum 121 in the rotation direction with respect to the position where the photosensitive drum 121 and the developing device 130 face each other. Is provided.

  The transfer unit 140 is a roller-shaped member, and includes a metal rotation center shaft 141 and a semiconductive rubber layer 142 provided around the rotation center shaft 141. The rotation center axis 141 is disposed in parallel with the main scanning direction (z-axis direction in the figure). A high voltage power source is connected to the rotation center shaft 141. The semiconductive rubber layer 142 is configured to exhibit semiconductivity by kneading carbon black or the like into synthetic rubber.

  The transfer unit 140 is rotated counterclockwise in the drawing while a predetermined transfer voltage is applied to the drum body 121a of the photosensitive drum 121, whereby the toner T carried on the image carrying surface 121b1. Can be transferred onto the paper P.

<< paper cassette >>
The paper feed cassette 150 is disposed below the developing device 130. The paper feed cassette case 151 is a box-shaped member that constitutes the casing of the paper feed cassette 150 and is formed to open upward. The sheet feeding cassette case 151 is configured to accommodate a large number of sheet-like sheets P having a maximum A4 size (width 210 mm × length 297 mm) in a stacked state.

  A paper pressing plate 153 is disposed in the paper feed cassette case 151. The paper pressing plate 153 is supported by the paper feed cassette case 151 so that the rear end can swing along the vertical direction in the figure with the front end as the center. The rear end of the paper pressing plate 153 is urged upward by a spring (not shown).

<< Paper Conveying Section >>
In the main body casing 112, a paper transport unit 160 is accommodated.

  The paper transport unit 160 is configured to be able to supply the paper P to the transfer position TRP where the transfer unit 140 and the image carrying surface 121b1 face each other in the closest state. The paper transport unit 160 includes a paper feed roller 161, a paper guide 163, and a paper transport guide roller 165.

  The paper feed roller 161 is composed of a rotation center axis parallel to the main scanning direction and a surrounding rubber layer. The paper feed roller 161 is disposed so as to face the most distal portion of the paper P placed on the paper pressing plate 153 in the paper feed cassette case 151 in the paper transport direction. The paper guide 163 and the paper transport guide roller 165 are configured to guide the paper P fed by the paper feed roller 161 to the transfer position TRP.

<< Fixing part >>
A fixing unit 170 is accommodated in the main body casing 112. The fixing unit 170 is disposed at a position downstream of the transfer position TRP in the paper transport direction.

  The fixing unit 170 heats the paper P to which the toner T has adhered through the transfer position TRP while applying pressure, so that the image formed by the toner T formed on the paper P can be fixed on the paper P. It is configured. The fixing unit 170 includes a heating roller 172 and a pressure roller 173.

  The heating roller 172 includes a metal cylinder whose surface has been subjected to a mold release process, and a halogen lamp housed in the cylinder. The pressure roller 173 includes a metal rotation center shaft and a silicon rubber rubber layer provided around the rotation center shaft. The heating roller 172 and the pressure roller 173 are disposed so as to press each other with a predetermined pressure.

  The heating roller 172 and the pressure roller 173 are configured and arranged so that the paper P can be sent out toward the paper discharge port 112a while pressing and heating the paper P.

<< Control part >>
A control unit 180 is accommodated in the main body casing 112. The control unit 180 includes a ROM, a CPU, a RAM, a rewritable ROM, and an interface.

  In the ROM, various routines and tables executed by the CPU for the operation of the laser printer 100 are stored in advance. The CPU is configured to read out a routine or the like from the ROM and store the data in the RAM or rewritable ROM as appropriate, and execute the routine.

  The CPU is connected to various sensors and switches provided in the laser printer 100 via an interface. In addition, the CPU is configured to be able to control the operation of each unit such as the electrostatic latent image forming unit 120, the developing device 130, and the transfer unit 140 via the interface.

<Outline of image forming operation by laser printer>
Hereinafter, an outline of an image forming operation by the laser printer 100 having the above-described configuration will be described with reference to the drawings. The following operations are all performed under the control of the CPU provided in the control unit 180.

<< Paper feeding action >>
First, referring to FIG. 1, the paper P stacked on the paper pressing plate 153 is urged upward toward the paper feed roller 161 by the paper pressing plate 153. As a result, the uppermost sheet P stacked on the sheet pressing plate 153 comes into contact with the peripheral surface of the sheet feeding roller 161.

  The paper feed roller 161 is driven to rotate clockwise in the drawing, so that the leading end of the paper P in the paper transport direction is sent toward the paper guide 163. The paper P is fed to the transfer position TRP by the paper guide 163 and the paper transport guide roller 165.

<< Carrying of toner image on image carrying surface >>
As described above, while the paper P is being conveyed toward the transfer position TRP, an image of the toner T is carried on the image carrying surface 121b1 that is the circumferential surface of the photosensitive drum 121 as follows.

<<< Formation of electrostatic latent image >>>
First, the image carrying surface 121b1 of the photosensitive drum 121 is uniformly charged positively by the charger 123.

  Referring to FIG. 3, the image bearing surface 121b1 charged by the charger 123 is rotated to the scan position SP which is a position facing (directly facing) the scanner unit 122 by the clockwise rotation of the photosensitive drum 121 in the drawing. It moves along the sub-scanning direction.

  At the scan position SP, the laser beam LB modulated based on the image information is irradiated onto the image bearing surface 121b1 while being scanned along the main scanning direction. Depending on the modulation state of the laser beam LB, a portion where the positive charge on the image bearing surface 121b1 disappears occurs. As a result, an electrostatic latent image LI is formed on the image bearing surface 121b1 by an image-like distribution of positive charges.

  The electrostatic latent image LI formed on the image bearing surface 121b1 moves toward the developing position DP by the clockwise rotation of the photosensitive drum 121 in the drawing.

<<< Toner fluidization >>>
Referring to FIG. 5, a predetermined AC voltage is output from a power supply device (not shown) to the vibration generator 137a.

  As a result, the vibration generating unit 137a vibrates. The vibration of the vibration generating unit 137a is transmitted to the vibrator 136 through the vibration transmitting unit 137b. Then, the vibrator 136 vibrates in the developing casing 131 while being supported by the elastic seal 138.

  Referring to FIG. 2, the vibration of the vibrator 136 vibrates the toner reservoir TP (toner T stored at the bottom of the toner storage area 130a in the developing casing 131). The excited toner reservoir TP is fluidized like a liquid.

<<< Charged toner transport >>>
Referring to FIG. 2, a predetermined voltage (similar to that shown in FIG. 4) is applied to the counter wiring substrate 135. As a result, a predetermined traveling-wave electric field is formed on the counter wiring substrate 135 (the toner sub-transport surface 135a and the toner auxiliary transport surface 135a ′).

  Then, the toner T located at the rear end of the sufficiently fluidized toner reservoir TP and in the vicinity of the toner sub-transport surface 135a (toner transport start region TTA) is placed on the toner sub-transport surface 135a. The traveling wave electric field described above acts.

  As a result, the toner T starts from the toner conveyance start area TTA, and the toner sub-carrying surface 135a having a constant slope and a cylindrical inner surface portion of the auxiliary toner conveying surface 135a ′ are moved upward. It is transported in the sub transport direction TTD2.

  The toner transport start area TTA is reduced along the toner sub-transport surface 135a and the toner auxiliary transport surface 135a ′ by lowering the highest position of the toner reservoir TP (toner reservoir upper surface TPS) as the toner is consumed. Move forward and downward.

  Then, the toner T that has risen above the toner auxiliary transport surface 135a ′ reaches the position where the most upstream portion (the lower left end in the drawing) of the transport wiring substrate 133 and the counter wiring substrate 135 face each other in the main toner transport direction TTD1. Be guided.

  The toner T guided to the space between the transport wiring substrate 133 and the counter wiring substrate 135 is transferred to the toner main transport surface 133a of the transport wiring substrate 133, the toner auxiliary transport surface 135a ′ and the toner sub-transport surface 135a of the counter wiring substrate 135. Is conveyed toward the developing position DP by the traveling wave-like electric field generated in this manner.

  The toner T that has passed through the development position DP falls downward from the foremost end of the toner main transport surface 133a, thereby returning to the toner reservoir TP.

  The toner T transport operation by the counter wiring substrate 135 is the same as the toner T transport operation by the transport wiring substrate 133. Therefore, the toner T transporting operation by the transport wiring board 133 will be described in detail below.

  FIG. 6 is an enlarged side sectional view showing the periphery of the toner main transport surface 133a in the transport wiring board 133 shown in FIG. In FIG. 3, the transport electrode 133b connected to the power supply circuit VA is shown as the transport electrode 133bA in FIG. The same applies to the transport electrodes 133bB to 133bD.

  Referring to FIGS. 4 and 6, at time t1 in FIG. 4, as shown in FIG. 6A, at the position between AB, which is the position between the transport electrode 133bA and the transport electrode 133bB. Then, an electric field EF1 is formed in the direction opposite to the toner main transport direction TTD1 (the direction opposite to x in FIG. 6).

  On the other hand, an electric field EF2 in the same direction as the toner main transport direction TTD1 (the x direction in FIG. 6) is formed at the inter-CD position between the transport electrode 133bC and the transport electrode 133bD.

  A direction along the toner main transport direction TTD1 is located at the position between BC, which is a position between the transport electrode 133bB and the transport electrode 133bC, and at the position between the DA, which is a position between the transport electrode 133bD and the transport electrode 133bA. The electric field is not formed.

  That is, at time t1, the positively charged toner T receives an electrostatic force in the direction opposite to the main toner transport direction TTD1 at the position between AB.

  Further, at the position between BC and the position between DA, the positively charged toner T receives almost no electrostatic force in the direction along the toner main transport direction TTD1.

  Further, at the position between the CDs, the positively charged toner T receives an electrostatic force in the same direction as the toner main transport direction TTD1.

  Therefore, at time t1, the positively charged toner T is collected at the position between the DAs. Similarly, at time t2, the positively charged toner T is collected at the position between AB. Next, at time t3, the positively charged toner T is collected at the position between BC.

  As described above, the region where the toner T is collected moves in the main toner transport direction TTD1 along the main toner transport surface 133a as time passes.

<<< Development of electrostatic latent image >>>
Referring to FIG. 3, as described above, the positively charged toner T is supplied to the development position DP.

  In the vicinity of the developing position DP, the toner T adheres to the portion on the image bearing surface 121b1 where the positive charge in the electrostatic latent image LI has disappeared. That is, the electrostatic latent image LI on the image bearing surface 121b1 of the photosensitive drum 121 is developed with the toner T.

  In this way, the image by the toner T is carried on the image carrying surface 121b1.

<< Transfer of toner image from image bearing surface to paper >>
Referring to FIG. 1, an image formed by the toner T carried on the image carrying surface 121b1 of the photosensitive drum 121 as described above is transferred to the transfer position TRP by rotating the image carrying surface 121b1 clockwise in the drawing. It is conveyed toward.

  At this transfer position TRP, the image of the toner T is transferred onto the paper P from the image carrying surface 121b1.

<< Fixing / Ejecting >>
The paper P on which the image of the toner T has been transferred at the transfer position TRP is sent to the fixing unit 170 along the paper transport path PP.

  The paper P is heated while being pressed by being sandwiched between the heating roller 172 and the pressure roller 173. As a result, the image of the toner T is fixed on the surface of the paper P.

  Thereafter, the paper P is sent to the paper discharge port 112a and discharged onto the paper discharge tray 114 through the paper discharge port 112a.

<Operation / Effects of Configuration of Embodiment>
In the configuration of the present embodiment, the casing bottom plate 131b is formed in a flat plate shape that intersects the horizontal plane at a certain angle. The toner sub-transport surface 135a is formed in a planar shape that intersects the horizontal plane at a certain angle.

  Here, FIG. 7 is a side sectional view showing a state in which the amount of toner T stored (the amount of toner reservoir TP) in the developing casing 131 is reduced in the developing device 130 shown in FIG. FIG. 8 is a side sectional view showing a state in which the amount of toner T stored is further reduced in the developing device 130 shown in FIG. 2 than in the state shown in FIG.

  As shown in FIGS. 7 and 8, the toner reservoir upper surface TPS becomes gradually lower as the amount of toner T stored in the developing casing 131 decreases.

  Even in this case, in the configuration of the present embodiment, the angle (toner contact angle TCA) between the toner reservoir upper surface TPS and the toner sub-transport surface 135a in the toner transport start area TTA is substantially constant.

  Referring to FIGS. 7 and 8, in the present embodiment, the toner contact angle TCA is substantially constant even when the amount of toner T stored is reduced.

  Therefore, in the present embodiment, the toner T transport state from the toner transport start area TTA toward the downstream side in the toner sub transport direction TTD2 is substantially constant. That is, the conveyance state of the toner T is stabilized.

  Therefore, according to the configuration of the present embodiment, the toner T is poorly transported (extremely low) when the amount of toner T stored in the developing casing 131 (the amount of toner T stored in the bottom of the toner storage region 130a) decreases. Occurrence of a decrease in the transport amount or the like can be effectively suppressed.

  In the configuration of the present embodiment, the casing bottom plate 131b is formed in a flat plate shape that intersects the horizontal plane at a small angle (30 degrees or less). Further, the toner sub-transport surface 135a is formed in a planar shape that intersects the horizontal plane at a small angle (30 degrees or less). The angle formed between the toner sub-transport surface 135a and the horizontal plane is substantially equal to the toner contact angle TCA.

  According to this configuration, the toner contact angle TCA, which is the angle between the toner reservoir upper surface TPS and the toner sub-transport surface 135a, is a small angle (30 degrees or less). Therefore, most of the toner T in the toner transport start area TTA is subjected to the action of a traveling wave electric field on the toner sub-transport surface 135a.

  Thus, the toner T can be satisfactorily supplied from the toner transport start area TTA to the downstream toner sub-transport surface 135a in the toner sub-transport direction TTD2.

  Further, the size of the developing casing 131 in the height direction is reduced. Thereby, the developing device 130 can be thinned. Therefore, the laser printer 100 can be further reduced in size.

  In the configuration of the present embodiment, a vibrator 136 and a vibrator driving unit 137 are provided as a developer vibration unit for vibrating the toner T accommodated (stored) in the development casing 131.

  According to such a configuration, the toner T (toner reservoir TP) stored in the developing casing 131 is fluidized well. At this time, stress such as cohesive force and shear force applied to the toner T is extremely small.

  Therefore, according to such a configuration, the supply state of the toner T to the toner sub-transport surface 135a, the toner auxiliary transport surface 135a ', and the toner main transport surface 133a can be made uniform. Therefore, the transport state of the toner T on the toner sub-transport surface 135a, the toner auxiliary transport surface 135a ', and the toner main transport surface 133a can be made uniform.

  As described above, according to the configuration of this embodiment, the toner T can be transported by the traveling wave electric field and the toner T can be supplied to the developing position DP more uniformly. Therefore, the occurrence of density unevenness is effectively suppressed, and good image formation becomes possible.

  In the configuration of this embodiment, the vibrator 136 is disposed in the developing casing 131 so as to be separated from the toner sub-transport surface 135a. The vibrator 136 is swingably supported by the casing side plate 131c via an elastic seal 138.

  In the configuration of the present embodiment, the vibrator driving unit 137 is disposed outside the developing casing 131. The vibrator driving unit 137 can vibrate the vibrator 136 from the outside of the developing casing 131.

  According to such a configuration, the occurrence of a disturbance in the formed image due to fluctuation of the predetermined positional relationship between the toner main transport surface 133a and the image carrying surface 121b1 at the development position DP due to the vibration of the vibrator 136 is as much as possible. Can be suppressed.

  Further, the generation of noise due to all the vibration of the vibrator 136 being directly transmitted to the developing casing 131 can be suppressed as much as possible.

<Example of modification>
Note that, as described above, the above-described embodiments are merely examples of typical embodiments of the present invention that the applicant has considered to be the best at the time of filing of the present application. Therefore, the present invention is not limited to the above-described embodiment. Therefore, it goes without saying that various modifications can be made to the above-described embodiment within the scope not changing the essential part of the present invention.

  Hereinafter, some modifications will be illustrated. In the following description of modifications, members having the same configuration and function as those described in the above-described embodiment are denoted by the same reference numerals as those in the above-described embodiment. And about description of this member, the description in the above-mentioned embodiment shall be used in the range which is not technically consistent.

  Needless to say, the modifications are not limited to those listed below. In addition, a plurality of modified examples can be applied in a composite manner as appropriate within a technically consistent range.

  The present invention (especially those expressed functionally and functionally in each component constituting the means for solving the problems of the present invention) is described in the above-described embodiments and the following modifications. On the basis of it, it should not be interpreted as limited.

  Such a limited interpretation, while improperly harming the applicant's interests (rushing to file under a prior application principle), improperly imitates (for the purpose of protecting and using the invention) Contrary to the purpose of patent law) not allowed.

  (1) The application target of the present invention is not limited to a so-called monochrome laser printer capable of forming a monochrome image. For example, the present invention can be preferably applied to a so-called electrophotographic image forming apparatus such as a laser printer capable of forming a multicolor (full color) image or a monochromatic and color copier.

  Alternatively, the present invention can be suitably applied to an image forming apparatus of a system other than the above-described electrophotographic system (for example, an image forming apparatus of a toner jet system or an ion flow system that does not use a photoreceptor).

  (2) The configurations of the toner electric field transport body 132, the transport wiring board 133, and the counter wiring board 135 are not limited to those shown in the above embodiment.

  For example, the transport electrode 133b can be embedded in the transport electrode support substrate 133c so as not to protrude from the surface of the transport electrode support substrate 133c. Further, the transport electrode coating layer 133d can be omitted.

  Alternatively, the transport electrode 133 b can be formed directly on the transport substrate support member 134. In this case, the transport electrode 133 b can be embedded in the transport substrate support member 134 so as not to protrude from the upper surface of the transport substrate support member 134. In this case, the toner main transport surface 133 a is configured by the upper surface of the transport substrate support member 134.

  For example, the counter electrode 135b may be embedded in the counter electrode support substrate 135c so as not to protrude from the surface of the counter electrode support substrate 135c. Further, the counter electrode coating layer 135d may be omitted.

  Alternatively, the counter electrode 135b can be directly formed on the inner wall surface of the casing bottom plate 131b. In this case, the counter electrode 135b can be embedded in the casing bottom plate 131b so as not to protrude from the inner wall surface of the casing bottom plate 131b. In this case, the toner sub-transport surface 135a is constituted by the inner wall surface of the casing bottom plate 131b.

  The longitudinal direction of the transport electrode 133b and the counter electrode 135b may be parallel to the main scanning direction as in the above-described embodiment, or may intersect the main scanning direction.

  The arrangement direction of the transport electrode 133b and the counter electrode 135b may be parallel to the sub-scanning direction in a plan view as in the above-described embodiment, or a direction intersecting the sub-scanning direction in a plan view. It may be.

  There are no particular limitations on the shape of the transport electrode 133b and the counter electrode 135b and the electrical connection configuration. For example, the transport electrode 133b and the counter electrode 135b may be formed in various shapes such as a V shape, an arc shape, a wave shape, and a jagged shape, instead of the linear shape as in the above-described embodiment.

  The connection between the electrodes may be in various states such as every other one, every other two, etc., instead of every third as in the above-described embodiment. In this case, the corresponding power supply circuit is not four types, and the phase shift of each voltage waveform can be appropriately changed to 180 °, 120 °, or the like. Further, various voltage waveforms such as a rectangular wave and a sine wave can be used.

  (3) The developer excitation unit of the present invention is not limited to the arrangement and configuration disclosed in the above-described embodiment and the corresponding drawings.

  For example, the vibrator 136 may be provided in the vicinity of the lowest position (the lower right end in FIG. 1) in the toner storage region 130a.

  Further, a plurality of vibrators 136 may be provided in the developing casing 131 (toner accommodation area 130a).

  FIG. 9 is a side sectional view showing the configuration of one modification of the laser printer 100 shown in FIG.

  As shown in FIG. 9, a downstream vibrator 1361, an intermediate vibrator 1362, and an upstream vibrator 1363 are provided in the developing casing 131 (toner accommodation region 130 a).

  The downstream vibrator 1361 is provided downstream of the center of the toner sub-transport surface 135a in the toner sub-transport direction TTD2. The upstream vibrator 1363 is provided upstream of the center of the toner sub-transport surface 135a in the toner sub-transport direction TTD2. The intermediate vibrator 1362 is provided between the downstream vibrator 1361 and the upstream vibrator 1363.

  A downstream vibrator driving unit 1371 is provided outside the developing casing 131 (toner accommodation region 130a) so as to correspond to the downstream vibrator 1361. Further, an intermediate vibrator driving unit 1372 is provided so as to correspond to the intermediate vibrator 1362. Further, an upstream vibrator driving unit 1373 is provided so as to correspond to the upstream vibrator 1363.

  Note that the intermediate vibrator 1362 may be omitted. Alternatively, a plurality of intermediate vibrators 1362 can be provided. Furthermore, the downstream vibrator driving unit 1371 to the upstream vibrator driving unit 1373 can be integrated.

  2 is directly provided in the vibrator 136 (downstream vibrator 1361 and the like in FIG. 9), so that the vibrator drive unit 137 (the downstream vibrator drive unit 1371 in FIG. 9 and the like) is provided. Etc.) may be omitted.

  Further, instead of the vibrator 136 and the vibrator driving unit 137 in FIG. 2, a diaphragm 139 can be used as shown in FIG. The vibration plate 139 is composed of a piezoelectric element, a vibrator, or the like that can generate vibrations when energized, like the vibration generating unit 137a (see FIG. 5) in the vibrator driving unit 137.

  As shown in FIG. 10, the diaphragm 139 may be provided on the casing bottom plate 131b. For example, the diaphragm 139 can be provided on the outer surface of the casing bottom plate 131b (the surface opposite to the inner surface facing the counter wiring substrate 135).

  Alternatively, the vibration plate 139 may be provided in the developing casing 131 (toner accommodation region 130a) so as to face the toner sub-transport surface 135a with a predetermined gap therebetween.

  According to such a configuration, the toner reservoir TP in the toner storage region 130a can be fluidized with a very simple device configuration.

  (4) The developer oscillating unit of the present invention can vibrate the entire toner reservoir TP even when the amount of toner T stored in the developing casing 131 (the amount of toner reservoir TP) decreases. It may be configured. Alternatively, it is preferable that the developer excitation unit of the present invention is configured to be able to vibrate at least the toner conveyance start area TTA.

  For example, referring to FIG. 9, a toner amount sensor 182 may be provided in the developing casing 131 (toner accommodation area 130a).

  The toner amount sensor 182 is configured to output a signal corresponding to the position of the toner reservoir upper surface TPS, that is, the amount of toner T in the toner containing area 130a. The toner amount sensor 182 is electrically connected to the control unit 180.

  In such a configuration, the excitation state of the plurality of vibrators (downstream vibrator 1361 and the like) is controlled by the control unit 180 in accordance with the position of the toner reservoir upper surface TPS.

  For example, when the position of the toner reservoir upper surface TPS is high, all of the downstream vibrator 1361 to the upstream vibrator 1363 are excited. When the toner reservoir upper surface TPS becomes lower than the downstream vibrator 1361, the intermediate vibrator 1362 and the upstream vibrator 1363 are excited. When the toner reservoir upper surface TPS becomes lower than the intermediate vibrator 1362, the upstream vibrator 1363 is excited.

  Alternatively, for example, when the position of the toner reservoir upper surface TPS is high, only the downstream vibrator 1361 is excited. When the toner reservoir upper surface TPS becomes lower than the downstream vibrator 1361, only the intermediate vibrator 1362 is excited. When the toner reservoir upper surface TPS becomes lower than the intermediate vibrator 1362, only the upstream vibrator 1363 is excited.

  Alternatively, as illustrated in FIG. 10, when the diaphragm 139 is provided so as to correspond to the casing bottom plate 131 b, the casing bottom plate 131 b is excited by the diaphragm 139.

  As a result, even if the position of the toner reservoir upper surface TPS changes as the toner T is consumed, the toner conveyance start area TTA (see FIG. 8) can be vibrated reliably.

  (5) FIG. 11 is a side sectional view showing the configuration of another modification of the developing device 130 shown in FIG. FIG. 12 is a side sectional view showing a state in which the amount of toner T stored (the amount of toner reservoir TP) in the developing casing 131 is reduced in the developing device 130 shown in FIG.

  As shown in FIG. 11, the casing bottom plate 131b and the toner sub-transport surface 135a may be provided so as to form an angle of 60 degrees or more with the horizontal plane.

  According to this configuration, the size of the developing casing 131 (developing device 130) in the front-rear direction is reduced. Thereby, the apparatus configuration when a plurality of developing devices 130 are arranged in the front-rear direction can be reduced in size. That is, an image forming apparatus capable of forming a multicolor image can be reduced in size.

  Further, according to such a configuration, as shown in FIG. 12, when the amount of toner T stored in the developing casing 131 (the amount of toner reservoir TP) decreases, the toner reservoir TP is excited by the vibration plate 139 or the like. Even if not, the toner reservoir upper surface TPS may be horizontal due to the weight of the toner T.

  That is, the toner sub-transport surface 135a is a steeply inclined surface that forms an angle of 60 degrees or more with the horizontal plane, so that the toner T does not excite the toner reservoir TP by the vibration plate 139 or the like, so that the toner T has its own weight. The contact angle TCA can be made stable and substantially constant.

  Therefore, even when the amount of toner T stored in the developing casing 131 (the amount of toner reservoir TP) decreases, the state of supply (conveyance start) of toner T from the toner conveyance start area TTA is extremely simple. It can be well stabilized by the device configuration.

  (6) The counter wiring substrate 135 may be omitted partially or entirely.

  (7) In addition, what is expressed functionally and functionally in each element constituting the means for solving the problems of the present invention is the specific structure disclosed in the above-described embodiment or modification. In addition, any structure capable of realizing the action / function is included.

1 is a side sectional view showing a schematic configuration of a laser printer to which an embodiment of the present invention is applied. FIG. 2 is an enlarged side sectional view of an electrostatic latent image forming unit and a developing device shown in FIG. 1. FIG. 3 is an enlarged side cross-sectional view of a portion in the vicinity of a developing opening in the developer electric field carrier shown in FIG. 2. 4 is a graph showing a waveform of a voltage generated by the power supply circuit shown in FIG. 3. FIG. 3 is a cross-sectional view seen from the front side (front side), showing an enlarged portion in the vicinity of the vibrator in the developing casing shown in FIG. 2. FIG. 4 is an enlarged side cross-sectional view illustrating the periphery of a toner main transport surface in the transport wiring board illustrated in FIG. 3. FIG. 3 is a side sectional view showing a state in which the toner storage amount (toner storage amount) in the developing casing is reduced in the developing device shown in FIG. 2. FIG. 8 is a side sectional view showing a state in which the toner storage amount is further reduced in the developing device shown in FIG. 2 than in the state shown in FIG. 7. It is a sectional side view which shows the structure of one modification of the laser printer shown by FIG. It is a sectional side view which shows the structure of the other modification of the laser printer shown by FIG. FIG. 10 is a side sectional view showing a configuration of another modification of the developing device shown in FIG. 1. FIG. 12 is a side sectional view showing a state in which the toner storage amount (toner storage amount) in the developing casing is reduced in the developing device shown in FIG. 11.

Explanation of symbols

100: Laser printer (image forming apparatus)
120. Electrostatic latent image forming unit 121 ... Photosensitive drum (electrostatic latent image carrier / developer carrier)
121b ... photosensitive member layer 121b1 ... image carrying surface (latent image forming surface / developer carrying surface)
130... Development device (developer supply device)
130a ... Toner storage area 131 ... Development casing (developer storage casing)
131a ... casing upper surface cover (top plate)
131a1... Development unit facing plate 131a2... Development opening (opening)
131b ... casing bottom plate (bottom plate)
131c ... casing side plate 131c1 ... casing through hole 132 ... toner electric field carrier (developer carrier)
133... Transport wiring board 133 a... Toner main transport surface (developer main transport surface)
133b ... Transport electrode (first transport electrode)
133c ... Transport electrode support substrate 133d ... Transport electrode coating layer 134 ... Transport substrate support member 135 ... Counter wiring substrate 135a ... Toner sub-transport surface (developer sub-transport surface)
135a '... toner auxiliary conveyance surface (developer auxiliary conveyance surface)
135b ... Counter electrode (second transport electrode)
135c ... Counter electrode support substrate 135d ... Counter electrode coating layer 136 ... Vibrator (developer excitation part)
1361... Downstream vibrator (developer shaker)
1362... Intermediate vibrator (developer shaker)
1363. Upstream vibrator (developer vibration part)
137... Vibrator drive unit (developer shaker)
137a ... vibration generating unit 137b ... vibration transmitting unit 1371 ... downstream vibrator driving unit (developer exciting unit)
1372: Intermediate vibrator drive unit (developer excitation unit)
1373: Upstream vibrator driving section (developer vibration section)
138 ... Elastic seal 139 ... Diaphragm (developer excitation part)
180 ... control unit 182 ... toner amount sensor DP ... development position LB ... laser beam LI ... electrostatic latent image P ... paper PP ... paper transport path T ... toner (developer)
TP ... Toner reservoir TCA ... Toner contact angle TPS ... Toner reservoir upper surface TTA ... Toner transport start area TTD1 ... Toner main transport direction (developer main transport direction)
TTD2: Toner sub-transport direction (developer sub-transport direction)

Claims (10)

A latent image forming surface that is formed in parallel with a predetermined main scanning direction and configured to form an electrostatic latent image by a potential distribution; and the latent image forming surface is a sub-surface orthogonal to the main scanning direction. An electrostatic latent image carrier configured to be movable along a scanning direction;
A developer supply device arranged to face the electrostatic latent image carrier and configured to supply the developer to the latent image forming surface in a charged state;
An image forming apparatus comprising:
The developer supply device includes:
Crosses the horizontal plane so that the angle formed between the top plate having an opening formed at a position facing the electrostatic latent image carrier and the horizontal plate and the horizontal plane is always constant. A plate-shaped bottom plate disposed as a developer, and a developer accommodating casing configured to accommodate the developer in a space surrounded by the box-shaped member,
The developer containing casing has a developer main transport surface parallel to the main scanning direction, and the developer main transport surface faces the electrostatic latent image carrier with the opening in the top plate interposed therebetween. A developer carrier disposed in the interior;
The developer is provided along the developer main transport surface so as to face the latent image forming surface, and a predetermined wave of the developer on the developer main transport surface is applied by applying a traveling wave voltage. A plurality of first transport electrodes configured to be transported in a transport direction and arranged along the sub-scanning direction;
An inner side of the bottom plate of the developer containing casing along the developer sub-transport surface formed in a slope shape rising toward the upstream end of the developer main transport surface in the developer main transport direction. It is provided along the wall surface, and the developer is transported in the developer sub-transport direction, which is a direction in which the developer ascends on the developer sub-transport surface toward the end by applying a traveling wave voltage. A plurality of second transport electrodes that are arranged along the sub-scanning direction, and
Equipped with a,
The developer sub-transport surface is configured so that, when the upper surface of the developer stored at the bottom in the space is lowered due to a decrease in the amount of the developer, a change in angle with the upper surface is suppressed. An image forming apparatus, characterized in that an angle formed with a horizontal plane is constant and provided in a planar shape intersecting the horizontal plane . The image forming apparatus according to claim 1,
The image forming apparatus, wherein the developer sub-transport surface is formed so that an angle formed with a horizontal plane is always 30 degrees or less. The image forming apparatus according to claim 1 , wherein:
The second transport electrode includes a developer auxiliary transport surface along an inner wall surface on the upstream side in the developer main transport direction with respect to the developer sub-transport surface and the opening of the top plate of the developer containing casing. Along the surface,
The downstream end of the developer sub-transport surface in the developer sub-transport direction is connected to the developer auxiliary transport surface,
The plurality of second transport electrodes are arranged such that the developer is directed toward a position where the end of the developer main transport surface and the developer sub-transport surface or the developer auxiliary transport surface face each other in the closest state. An image forming apparatus configured to be capable of conveying the image. The image forming apparatus according to any one of claims 1 to 3 ,
An image forming apparatus, further comprising: a developer vibration unit configured to vibrate the developer contained in the space . The image forming apparatus according to claim 4 ,
The developer excitation unit is
A vibrator disposed in the developer containing casing so as to be separated from the developer sub-transport surface and supported by the developer containing casing in a swingable manner;
A vibrator driving unit disposed outside the developer containing casing and configured to vibrate the vibrator from the outside of the developer containing casing;
An image forming apparatus comprising: A developer carrying surface that is parallel to a predetermined main scanning direction and has a developer carrying surface on which the developer can be carried, and the developer carrying surface can move along a sub-scanning direction orthogonal to the main scanning direction. In a developer supply device configured to be able to be supplied along a predetermined developer transport direction in a state where the developer is charged to a body,
Crossing the horizontal plane so that the angle between the top plate having an opening formed at a position facing the developer carrying member and the horizontal plate and the horizontal plane is always constant. A plate-like bottom plate disposed, and a developer containing casing configured to be able to contain the developer in a space surrounded by these members,
The developer containing casing has a developer main transport surface parallel to the main scanning direction, and the developer main transport surface faces the developer carrier with the opening in the top plate interposed therebetween. An arranged developer carrier;
The developer is provided along the developer main transport surface so as to face the developer carrying surface, and a predetermined wave of the developer on the developer main transport surface is applied by applying a traveling wave voltage. A plurality of first transport electrodes configured to be transported in the transport direction and arranged along the sub-scanning direction;
An inner side of the bottom plate of the developer containing casing along the developer sub-transport surface formed in a slope shape rising toward the upstream end of the developer main transport surface in the developer main transport direction. It is provided along the wall surface, and the developer is transported in the developer sub-transport direction, which is a direction in which the developer ascends on the developer sub-transport surface toward the end by applying a traveling wave voltage. A plurality of second transport electrodes arranged along the sub-scanning direction, and
Equipped with a,
The developer sub-transport surface is configured so that, when the upper surface of the developer stored at the bottom in the space is lowered due to a decrease in the amount of the developer, a change in angle with the upper surface is suppressed. A developer supplying apparatus, characterized in that the angle formed with a horizontal plane is constant and is provided in a plane that intersects the horizontal plane . The developer supply device according to claim 6 ,
The developer supply apparatus, wherein the developer sub-transport surface is formed so that an angle formed with a horizontal plane is always 30 degrees or less. The developer supply device according to claim 6 or 7 , wherein
The second transport electrode includes a developer auxiliary transport surface along an inner wall surface upstream of the opening in the developer main transport direction of the top plate of the developer containing casing and the developer containing casing. Along the surface,
The downstream end of the developer sub-transport surface in the developer sub-transport direction is connected to the developer auxiliary transport surface,
The plurality of second transport electrodes are arranged such that the developer is directed toward a position where the end of the developer main transport surface and the developer sub-transport surface or the developer auxiliary transport surface face each other in the closest state. A developer supply device configured to be capable of conveying the developer. The developer supply device according to any one of claims 6 to 8 ,
A developer supply apparatus, further comprising a vibrating body disposed at a bottom portion in the space . The developer supply device according to claim 9 ,
The vibrator is disposed in the developer accommodating casing so as to be separated from the developer sub-transport surface, and is supported by the developer accommodating casing so as to be swingable. Agent supply device.

Images