JP4458200B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus. Specifically, the present invention relates to a developer electric field transport device that is provided in an image forming apparatus and configured to transport a charged developer by an electric field.

  Many devices (developer electric field transport devices) for transporting a developer (dry developer or dry toner) using a traveling wave electric field in an image forming apparatus are conventionally known (for example, Japanese Patent Publication No. 5-31146). No., JP-A-2002-91159, JP-A-2003-98826, JP-A-2004-333845, JP-A-2005-275127, etc.).

  In such a developer electric field transport device, a number of long electrodes are arranged on an insulating substrate. These electrodes are arranged along the developer transport direction. The developer is stored in a predetermined casing.

  According to the developer electric field transport device having the above-described configuration, a traveling wave electric field is formed by sequentially applying a multiphase AC voltage to the electrodes. The charged developer is transported in the developer transport direction by the action of the traveling wave electric field.

Japanese Patent Publication No. 5-31146 JP 2002-91159 A JP 2003-98826 A JP 2004-333845 A JP 2005-275127 A

  In the developer electric field transport apparatus as described above, it is necessary to appropriately set the transport state of the developer in the developer transport direction in accordance with the structure and specifications of the image forming apparatus.

  For example, normally, the speed of movement of the developer stored in the casing (before being conveyed in the developer conveying direction) has almost no component along the developer conveying direction. For this reason, in the vicinity of the developer conveyance start position, it may be necessary to give a large acceleration along the developer conveyance direction to the developer. As a result, an amount of the developer necessary for good image formation can be conveyed quickly and smoothly toward a predetermined developer supply target (photosensitive drum or the like).

  Alternatively, when the process speed of the image forming apparatus (the peripheral speed of the photosensitive drum) is high, in order to suppress density unevenness due to the pitch between the electrodes, the position near the developer supply target is In some cases, it is necessary to reduce the developer conveyance speed.

  Alternatively, a “white background fogging” in which pixels are erroneously formed in a white background portion where pixels due to the developer are not formed may occur due to the ejection of the developer in the vicinity position or the retention of a large amount of the developer. possible. In order to suppress the occurrence of such “white background fogging”, it is necessary to suppress the ejection of the developer and the retention of a large amount of the developer in the vicinity.

  In this case, it is necessary to slow down the conveyance speed of the developer or to quickly return the developer that has passed through the developer supply target to the casing.

  The present invention has been made to solve such problems. That is, an object of the present invention is to provide a developer electric field transport device capable of appropriately setting the developer transport state in the developer transport direction, and image formation by the developer by providing the developer electric field transport device. An object of the present invention is to provide an image forming apparatus which can be performed satisfactorily.

  The developer electric field transport device of the present invention is configured to transport a charged developer along a predetermined developer transport direction by an electric field. The developer electric field transport device is disposed so as to face the developer carrier.

  The developer carrying member has a developer carrying surface. The developer carrying surface is a surface of the developer carrying body, on which the developer can be carried. The developer carrying surface is formed in parallel with a predetermined main scanning direction.

  The developer carrying surface can move along a predetermined moving direction. This moving direction can be set to be parallel to the sub-scanning direction orthogonal to the main scanning direction.

  Specifically, as the developer carrying member, for example, an electrostatic latent image carrying member configured to form an electrostatic latent image by a potential distribution can be used. In this case, the developer carrying surface is constituted by a latent image forming surface. The latent image forming surface is a peripheral surface of the electrostatic latent image carrier. The latent image forming surface is configured such that the electrostatic latent image can be formed.

  Alternatively, as the developer carrier, for example, a recording medium (paper or the like) conveyed along the sub-scanning direction can be used. In this case, the developer carrying surface is constituted by the surface (recorded surface) of the recording medium.

  Alternatively, as the developer carrying member, for example, a roller, a sleeve, or a belt-like member (a developing roller, a developing sleeve, an intermediate transfer belt, or the like) can be used. These members are arranged so as to face the recording medium and the electrostatic latent image carrier, for example. These members are configured and arranged so that the developer can be transferred onto the recording medium or the electrostatic latent image carrier.

  The developer electric field transport apparatus of the present invention includes a plurality of transport electrodes.

  The transport electrode is configured to have a longitudinal direction that intersects the sub-scanning direction. The transport electrodes are arranged along the sub-scanning direction. The plurality of transport electrodes are configured to generate a traveling wave electric field when a traveling wave voltage is applied, and to transport the developer in a predetermined developer transport direction by the electric field (and Arrangement).

  The image forming apparatus of the present invention includes an electrostatic latent image carrier as the developer carrier and a developer supply device.

  The electrostatic latent image carrier has a latent image forming surface. This latent image forming surface is formed in parallel with a predetermined main scanning direction. The latent image forming surface is configured such that an electrostatic latent image can be formed by a potential distribution. 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. The developer supply device includes the developer electric field transport device.

  In order to achieve the above-described object in the present invention, the developer electric field transport device of the present invention and the image forming apparatus provided with the same can be configured as follows.

  (1) The developer electric field transport device (the developer supply device) includes an electrode support member and a transport electrode covering member.

  The electrode support member is configured to support the transport electrode. The transport electrode is supported on the surface of the electrode support member.

  The transport electrode covering member is formed to cover the surface of the electrode support member and the transport electrode. The transport electrode covering member has a developer transport surface. The developer transport surface is a surface that is parallel to the main scanning direction and faces the developer carrying surface (latent image forming surface).

  In addition, the developer electric field transport device (the developer supply device) may include a transport electrode coating intermediate layer. The transport electrode coating intermediate layer is formed between the transport electrode coating member and the transport electrode.

  In the developer electric field transport device (the developer supply device), a facing region where the developer carrying surface and the developer transport surface face each other and other portions have the following characteristic configurations. Yes.

  (1-1) The transport electrode covering member may be configured such that the relative permittivity is lower on the upstream side and the downstream side in the developer transport direction than on the facing region.

  In this configuration, when a traveling-wave voltage is applied to the transport electrode, the upstream side and the downstream side of the developer transport surface on which the developer can be transported than the facing region. The strength of the electric field in the nearby space is increased. That is, the electric field strength is lower in the facing region than in the upstream side. In addition, the electric field strength is higher on the downstream side than on the facing region.

  Therefore, for example, at the developer transport start position on the developer transport surface (for example, the most upstream portion of the developer transport surface in the developer transport direction), the motion in the developer transport direction is almost reduced. A large acceleration along the developer transport direction can be given to the developer that is not.

  Alternatively, for example, the developer accelerated on the upstream side of the facing area can be decelerated in the facing area. As a result, unevenness in the amount of the developer in the developer transport direction can be effectively suppressed in the facing region.

  Alternatively, for example, the developer that has passed through the facing region can be accelerated in a direction to leave the facing region toward the downstream side. Accordingly, a large amount of the developer can be prevented from staying in the facing region.

  Thus, according to such a configuration, the state of transport of the developer in the developer transport direction can be set appropriately. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (1-2) The transport electrode covering member may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area. The upstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most upstream portion and the opposing region.

  Here, in the most upstream area, the upstream intermediate section, and the counter area, the relative permittivity changes stepwise from the most upstream section through the upstream intermediate section to the counter area. The transport electrode covering member may be configured. Alternatively, the transport electrode covering member in the most upstream part, the upstream intermediate part, and the opposing area may be configured so that the relative permittivity continuously changes from the most upstream part to the opposing area. Good.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part through the upstream intermediate part to the opposing region.

  Thereby, for example, the developer can be smoothly decelerated as it goes from the most upstream area to the facing area.

  (1-3) The transport electrode covering member may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area. The downstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most downstream portion and the opposing region.

  Here, in the facing region, the downstream intermediate portion, and the most downstream portion, the relative permittivity changes stepwise from the facing region through the downstream intermediate portion to the most downstream portion. The transport electrode covering member may be configured. Alternatively, the transport electrode covering member in the facing region, the downstream intermediate portion, and the most downstream portion may be configured so that the relative permittivity continuously changes from the facing region to the most downstream portion. Good.

  In such a configuration, the electric field strength gradually increases from the facing region through the downstream intermediate portion to the most downstream portion.

  Thereby, for example, the developer can be smoothly accelerated from the facing region toward the most downstream portion.

  (1-4) The transport electrode covering intermediate layer may be configured such that the relative permittivity is lower on the upstream side and the downstream side in the developer transport direction than on the facing region.

  In such a configuration, when a traveling-wave voltage is applied to the carrier electrode, the electric field strength is higher on the upstream side and the downstream side than on the facing region.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (1-5) The transport electrode covering intermediate layer may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area. The upstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most upstream portion and the opposing region.

  Here, in the most upstream area, the upstream intermediate section, and the counter area, the relative permittivity changes stepwise from the most upstream section through the upstream intermediate section to the counter area. The transport electrode covering intermediate layer may be configured. Alternatively, the transport electrode covering intermediate layer in the uppermost stream part, the upstream intermediate part, and the opposite area is configured so that the relative permittivity continuously changes from the uppermost stream part to the opposite area. Also good.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part through the upstream intermediate part to the opposing region.

  (1-6) The transport electrode covering intermediate layer may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area. The downstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most downstream portion and the opposing region.

  Here, in the facing region, the downstream intermediate portion, and the most downstream portion, the relative permittivity changes stepwise from the facing region through the downstream intermediate portion to the most downstream portion. The transport electrode covering intermediate layer may be configured. Alternatively, the transport electrode covering intermediate layer in the counter area, the downstream intermediate section, and the most downstream section is configured so that the relative permittivity continuously changes from the counter area to the most downstream section. Also good.

  In such a configuration, the electric field strength gradually increases from the facing region through the downstream intermediate portion to the most downstream portion.

  (1-7) The transport electrode covering member may be formed so that the upstream side and the downstream side in the developer transport direction are thinner than the facing region.

  In such a configuration, when a traveling-wave voltage is applied to the carrier electrode, the electric field strength is higher on the upstream side and the downstream side than on the facing region.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (1-8) The transport electrode covering member may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area. The upstream intermediate portion is configured to have a thickness intermediate between the most upstream portion and the facing region.

  Here, as the thickness changes stepwise from the most upstream part through the upstream intermediate part to the opposing region, the upstream part, the upstream intermediate part, and the opposing region in the opposing region A transport electrode covering member may be configured. Alternatively, the transport electrode covering member in the most upstream portion, the upstream intermediate portion, and the facing region may be configured so that the thickness continuously changes from the most upstream portion to the facing region. .

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part through the upstream intermediate part to the opposing region.

  (1-9) The transport electrode covering member may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area. The downstream intermediate portion is configured to have a thickness intermediate between the most downstream portion and the facing region.

  Here, the thickness in the opposing region, the downstream intermediate portion, and the most downstream portion so that the thickness changes stepwise from the opposing region through the downstream intermediate portion to the most downstream portion. A transport electrode covering member may be configured. Alternatively, the transport electrode covering member in the facing region, the downstream intermediate portion, and the most downstream portion may be configured so that the thickness continuously changes from the facing region to the most downstream portion. .

  In such a configuration, the electric field strength gradually increases from the facing region through the downstream intermediate portion to the most downstream portion.

  (1-10) The transport electrode covering intermediate layer may be configured such that the upstream side and the downstream side in the developer transport direction are thinner than the facing region.

  In such a configuration, when a traveling-wave voltage is applied to the carrier electrode, the electric field strength is higher on the upstream side and the downstream side than on the facing region.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (1-11) The transport electrode covering intermediate layer may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area. The upstream intermediate portion is configured to have a thickness intermediate between the most upstream portion and the facing region.

  Here, as the thickness changes stepwise from the most upstream part through the upstream intermediate part to the opposing region, the upstream part, the upstream intermediate part, and the opposing region in the opposing region A transport electrode covering intermediate layer may be configured. Alternatively, the transport electrode covering intermediate layer in the most upstream part, the upstream intermediate part, and the opposing area may be configured so that the thickness continuously changes from the most upstream part to the opposing area. Good.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part through the upstream intermediate part to the opposing region.

  (1-12) The transport electrode covering intermediate layer may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area. The downstream intermediate portion is configured to have a thickness intermediate between the most downstream portion and the facing region.

  Here, the thickness in the opposing region, the downstream intermediate portion, and the most downstream portion so that the thickness changes stepwise from the opposing region through the downstream intermediate portion to the most downstream portion. A transport electrode covering intermediate layer may be configured. Alternatively, even if the counter electrode, the downstream intermediate portion, and the transport electrode covering intermediate layer in the most downstream portion are configured so that the thickness continuously changes from the counter region to the most downstream portion. Good.

  In such a configuration, the electric field strength gradually increases from the facing region through the downstream intermediate portion to the most downstream portion.

  (1-13) In the case where the transport electrode covering intermediate layer is formed so that the upstream side and the downstream side in the developer transport direction are thinner than the facing region, The transport electrode is formed such that a laminate with the transport electrode covering member is formed in a flat plate shape having a substantially constant thickness, and the relative permittivity of the transport electrode covering member is lower than that of the transport electrode covering intermediate layer. A covering intermediate layer and the transport electrode covering member may be configured.

  In such a configuration, the (synthetic) relative dielectric constant of the laminate of the transport electrode covering member and the transport electrode covering intermediate layer is higher in the developer transport direction than in the opposing region. Will be lower. Accordingly, when a traveling wave voltage is applied to the transport electrode, the electric field strength can be higher on the upstream side and the downstream side than on the facing region.

  (1-14) The transport electrode may be formed so that the upstream side and the downstream side in the developer transport direction are thicker than the facing region.

  In such a configuration, when a traveling-wave voltage is applied to the carrier electrode, the electric field strength is higher on the upstream side and the downstream side than on the facing region.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (1-15) The transport electrode in the most upstream area in the developer transport direction is thicker than the transport electrode in the upstream intermediate section that is intermediate between the most upstream section and the facing region, and is in the upstream intermediate area. The transport electrode of the part may be formed to be thicker than the transport electrode in the counter area.

  Here, the transport electrode may be configured such that the thickness changes stepwise from the most upstream part to the counter area through the upstream intermediate part. Alternatively, the transport electrode may be configured such that the thickness continuously changes from the most upstream part to the counter area.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part through the upstream intermediate part to the opposing region.

  (1-16) The transport electrode at the most downstream portion in the developer transport direction is thicker than the transport electrode at the downstream intermediate portion that is intermediate between the most downstream portion and the facing region, and is at the downstream intermediate position. The transport electrode of the part may be formed to be thicker than the transport electrode in the counter area.

  Here, the transport electrode may be configured such that the thickness changes stepwise from the facing region through the downstream intermediate portion to the most downstream portion. Alternatively, the transport electrode may be configured such that the thickness continuously changes from the facing region to the most downstream portion.

  In such a configuration, the electric field strength gradually increases from the facing region through the downstream intermediate portion to the most downstream portion.

  (2) The developer electric field transport device (the developer supply device) may include a plurality of counter electrodes, a counter electrode support member, and a counter electrode covering member.

  The counter electrode is disposed to face the transport electrode with a predetermined gap therebetween. The plurality of counter electrodes are arranged along the sub-scanning direction and configured to be able to transport the developer in the developer transport direction when a traveling wave voltage is applied.

  The counter electrode support member is configured to support the counter electrode on the surface thereof. The counter electrode support member is disposed to face the transport electrode support member with the gap interposed therebetween.

  The counter electrode covering member is formed to cover the surface of the counter electrode support member and the counter electrode.

  Further, the developer electric field transport device (the developer supply device) may include a counter electrode covering intermediate layer. The counter electrode covering intermediate layer is formed between the counter electrode covering member and the counter electrode.

  In the developer electric field transport device (the developer supply device), a facing area proximity portion and other portions close to the facing area have the following characteristic configurations.

  (2-1) The counter electrode covering member may be configured such that the relative permittivity is lower on the upstream side and the downstream side in the developer transport direction than on the counter area neighboring portion.

  In such a configuration, when a traveling-wave voltage is applied to the counter electrode, the developer transport is such that the developer can be transported on the upstream side and the downstream side of the counter area neighboring portion. The electric field strength in the space near the surface is increased. That is, the electric field strength is lower in the counter area neighboring area than in the upstream area. In addition, the electric field strength is higher on the downstream side than the counter area neighboring portion.

  Therefore, for example, at the developer transport start position on the developer transport surface (for example, the most upstream portion of the developer transport surface in the developer transport direction), the motion in the developer transport direction is almost reduced. A large acceleration along the developer transport direction can be given to the developer that is not.

  Alternatively, for example, the developer accelerated on the upstream side of the facing area proximity portion can be decelerated at the facing area proximity portion. As a result, unevenness in the amount of the developer in the developer transport direction can be effectively suppressed in the facing region.

  Alternatively, for example, the developer that has passed through the counter area can be accelerated in a direction away from the counter area toward the downstream side by an electric field stronger than the counter area proximity portion. Accordingly, a large amount of the developer can be prevented from staying in the facing region.

  Thus, according to such a configuration, the state of transport of the developer in the developer transport direction can be set appropriately. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (2-2) The counter electrode covering member may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area neighboring portion. The upstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most upstream portion and the counter area neighboring portion.

  Here, the most upstream part, the upstream intermediate part, and the opposing part so that the relative permittivity changes stepwise from the most upstream part through the upstream intermediate part to the opposing region proximity part. The counter electrode covering member in the region proximity portion may be configured. Alternatively, the counter electrode covering member in the most upstream portion, the upstream intermediate portion, and the counter region neighboring portion is configured so that the relative permittivity continuously changes from the most upstream portion to the counter region neighboring portion. May be.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part to the counter area neighboring part through the upstream intermediate part.

  Thereby, for example, the developer can be smoothly decelerated as it goes from the most upstream area toward the counter area (the counter area neighboring area).

  (2-3) The counter electrode covering member may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area neighboring portion. The downstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most downstream portion and the counter area neighboring portion.

  Here, the counter area proximity part, the downstream side intermediate part, and the counter area proximity part, so that the relative permittivity changes stepwise from the counter area proximity part through the downstream intermediate part to the most downstream part. The counter electrode covering member in the most downstream portion may be configured. Alternatively, the counter electrode covering member in the counter region proximity portion, the downstream intermediate portion, and the most downstream portion is configured so that the relative permittivity continuously changes from the counter region proximity portion to the most downstream portion. May be.

  In such a configuration, the electric field strength gradually increases from the counter area neighboring area through the downstream intermediate area to the most downstream area.

  Thereby, for example, the developer can be smoothly accelerated from the facing area (the facing area adjacent portion) toward the most downstream portion.

  (2-4) The counter electrode covering intermediate layer may be configured such that the relative permittivity is lower on the upstream side and the downstream side in the developer transport direction than on the counter area neighboring portion.

  In such a configuration, when a traveling wave voltage is applied to the counter electrode, the electric field strength is higher on the upstream side and the downstream side than on the counter area neighboring area.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (2-5) The counter electrode covering intermediate layer may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area neighboring portion. The upstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most upstream portion and the counter area neighboring portion.

  Here, the most upstream part, the upstream intermediate part, and the opposing part so that the relative permittivity changes stepwise from the most upstream part through the upstream intermediate part to the opposing region proximity part. The counter electrode covering intermediate layer in the region proximity portion may be configured. Alternatively, the counter electrode covering intermediate layer in the most upstream part, the upstream intermediate part, and the counter area proximate part is arranged so that the relative permittivity continuously changes from the most upstream part to the counter area proximate part. It may be configured.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part to the counter area neighboring part through the upstream intermediate part.

  (2-6) The counter electrode covering intermediate layer may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area neighboring portion. The downstream intermediate portion is configured such that the relative dielectric constant is intermediate between the most downstream portion and the counter area neighboring portion.

  Here, the counter area proximity portion, the downstream side intermediate section, and the counter area proximity section so that the relative permittivity changes stepwise from the counter area proximity section through the downstream intermediate section to the most downstream section. The counter electrode covering intermediate layer in the most downstream portion may be configured. Alternatively, the counter electrode covering intermediate layer in the counter region proximate portion, the downstream intermediate portion, and the most downstream portion so that the relative dielectric constant continuously changes from the counter region proximate portion to the most downstream portion. It may be configured.

  In such a configuration, the electric field strength gradually increases from the counter area neighboring area through the downstream intermediate area to the most downstream area.

  (2-7) The counter electrode covering member may be formed so that the upstream side and the downstream side in the developer transport direction are thinner than the counter area neighboring portion.

  In such a configuration, when a traveling wave voltage is applied to the counter electrode, the electric field strength is higher on the upstream side and the downstream side than on the counter area neighboring area.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (2-8) The counter electrode covering member may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area neighboring portion. The upstream intermediate portion is configured to have a thickness intermediate between the most upstream portion and the counter area neighboring portion.

  Here, the most upstream portion, the upstream intermediate portion, and the opposing region are arranged such that the thickness changes stepwise from the most upstream portion through the upstream intermediate portion to the opposing region adjacent portion. The counter electrode covering member in the proximity portion may be configured. Alternatively, the counter electrode covering member in the most upstream part, the upstream intermediate part, and the counter area neighboring part is configured so that the thickness continuously changes from the most upstream part to the counter area neighboring part. It may be.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part to the counter area neighboring part through the upstream intermediate part.

  (2-9) The counter electrode covering member may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area neighboring portion. The downstream intermediate portion is configured to have an intermediate thickness between the most downstream portion and the counter area neighboring portion.

  Here, the opposing region proximity portion, the downstream intermediate portion, and the most downstream portion are arranged so that the thickness changes stepwise from the opposing region proximity portion through the downstream intermediate portion to the most downstream portion. The counter electrode covering member in the downstream portion may be configured. Alternatively, the counter electrode covering member in the counter region proximity portion, the downstream intermediate portion, and the most downstream portion is configured so that the thickness continuously changes from the counter region proximity portion to the most downstream portion. It may be.

  In such a configuration, the electric field strength gradually increases from the counter area neighboring area through the downstream intermediate area to the most downstream area.

  (2-10) The counter electrode covering intermediate layer may be configured such that the upstream side and the downstream side in the developer transport direction are thinner than the counter area neighboring portion.

  In such a configuration, when a traveling wave voltage is applied to the counter electrode, the electric field strength is higher on the upstream side and the downstream side than on the counter area neighboring area.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (2-11) The counter electrode covering intermediate layer may include an upstream intermediate portion. The upstream intermediate portion is provided between the most upstream portion in the developer transport direction and the counter area neighboring portion. The upstream intermediate portion is configured to have a thickness intermediate between the most upstream portion and the counter area neighboring portion.

  Here, the most upstream portion, the upstream intermediate portion, and the opposing region are arranged such that the thickness changes stepwise from the most upstream portion through the upstream intermediate portion to the opposing region adjacent portion. The counter electrode covering intermediate layer in the proximity portion may be configured. Alternatively, the counter electrode covering intermediate layer in the most upstream part, the upstream intermediate part, and the counter area neighboring part is configured so that the thickness continuously changes from the most upstream part to the counter area neighboring part. May be.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part to the counter area neighboring part through the upstream intermediate part.

  (2-12) The counter electrode covering intermediate layer may include a downstream intermediate portion. The downstream intermediate portion is provided between the most downstream portion in the developer transport direction and the counter area neighboring portion. The downstream intermediate portion is configured to have an intermediate thickness between the most downstream portion and the counter area neighboring portion.

  Here, the opposing region proximity portion, the downstream intermediate portion, and the most downstream portion are arranged so that the thickness changes stepwise from the opposing region proximity portion through the downstream intermediate portion to the most downstream portion. The counter electrode covering intermediate layer in the downstream portion may be configured. Alternatively, the counter electrode proximity portion, the downstream intermediate portion, and the counter electrode covering intermediate layer in the most downstream portion are configured such that the thickness continuously changes from the counter region proximity portion to the most downstream portion. May be.

  In such a configuration, the electric field strength gradually increases from the counter area neighboring area through the downstream intermediate area to the most downstream area.

  (2-13) When the counter electrode covering intermediate layer is formed so that the upstream side and the downstream side in the developer transport direction are thinner than the counter area neighboring portion, the counter electrode covering intermediate layer The laminate of the layer and the counter electrode covering member is formed in a substantially flat plate shape, and the counter electrode covering member has a lower dielectric constant than the counter electrode covering intermediate layer. A counter electrode covering intermediate layer and the counter electrode covering member may be configured.

  In such a configuration, the (synthetic) relative dielectric constant of the laminate of the counter electrode covering member and the counter electrode covering intermediate layer is higher and lower in the developer transport direction than the counter area neighboring portion. The side is lower. As a result, when a traveling wave voltage is applied to the counter electrode, the electric field strength can be higher on the upstream side and the downstream side than on the counter area neighboring area.

  (2-14) The counter electrode may be formed so that the upstream side and the downstream side in the developer transport direction are thicker than the counter area neighboring portion.

  In such a configuration, when a traveling wave voltage is applied to the counter electrode, the electric field strength is higher on the upstream side and the downstream side than on the counter area neighboring area.

  Thereby, the conveyance state of the developer in the developer conveyance direction can be appropriately set. Therefore, according to such a configuration, image formation by the developer can be performed better.

  (2-15) The counter electrode in the most upstream area in the developer transport direction is thicker than the counter electrode in the upstream intermediate section that is intermediate between the most upstream area and the counter area neighboring area, and is upstream of the counter electrode. The counter electrode in the side intermediate part may be formed to be thicker than the counter electrode in the counter area neighboring part.

  Here, the counter electrode may be configured such that the thickness changes stepwise from the most upstream part through the upstream intermediate part to the counter area neighboring part. Alternatively, the counter electrode may be configured such that the thickness continuously changes from the most upstream part to the counter area neighboring part.

  In such a configuration, the intensity of the electric field gradually decreases from the most upstream part to the counter area neighboring part through the upstream intermediate part.

  (2-16) The counter electrode in the most downstream portion in the developer transport direction is thicker than the counter electrode in the downstream intermediate portion that is intermediate between the most downstream portion and the counter area neighboring portion, and is downstream of the counter electrode. The counter electrode in the side intermediate part may be formed to be thicker than the counter electrode in the counter area neighboring part.

  Here, the counter electrode may be configured such that the thickness changes stepwise from the counter area neighboring area through the downstream intermediate section to the most downstream area. Or the said counter electrode may be comprised so that thickness may change continuously from the said opposing area | region vicinity part to the said most downstream part.

  In such a configuration, the electric field strength gradually increases from the counter area neighboring area through the downstream intermediate area to the most downstream area.

  (3) As described above, the developer electric field transport device (the developer supply device) is more than the facing region where the developer carrying surface and the transport electrode face each other (and the facing region proximity portion adjacent thereto). However, the electric field strength is higher on the upstream side and the downstream side in the developer transport direction.

  In such a configuration, when traveling-wave voltage is applied to the transport electrode (and the counter electrode), the upstream side and the downstream side are more than the counter region (and the counter region neighboring portion). The strength of the electric field in the space near the developer transport surface where the developer can be transported increases.

  Accordingly, for example, at the developer transport start position on the developer transport surface (for example, the most upstream portion of the developer transport surface in the developer transport direction), the counter area (and the counter area proximity portion). ), The intensity of the electric field in the space near the developer transport surface where the developer can be transported becomes higher. Therefore, a large acceleration along the developer transport direction can be given to the developer that hardly moves in the developer transport direction at the transport start position.

  In addition, for example, the electric field strength is lower in the counter area (and in the counter area proximity portion) than on the upstream side. Therefore, the developer can be decelerated in the facing area. As a result, unevenness in the amount of the developer in the developer transport direction can be effectively suppressed in the facing region.

  Also, for example, the electric field strength is higher in the downstream area than in the counter area (and the counter area proximity portion). Therefore, the developer that has passed through the facing region can be accelerated in a direction to leave the facing region toward the downstream side. Accordingly, a large amount of the developer can be prevented from staying in the facing region.

  Thus, according to the structure of this invention, the conveyance state of the said developer in the said developer conveyance direction can be set appropriately. Therefore, according to the configuration of the present invention, image formation by the developer can be performed more satisfactorily.

It is a side view showing a schematic structure of a laser printer concerning one embodiment of the present invention. FIG. 2 is an enlarged side cross-sectional view of a portion where the photosensitive drum and the toner supply device shown in FIG. 1 face each other. FIG. 3 is an enlarged side sectional view of the periphery of a developing position in the first embodiment of the toner supply device shown in FIG. 2. FIG. 3 is a graph showing a waveform of a voltage generated by each power supply circuit shown in FIG. 2. FIG. FIG. 3 is a side cross-sectional view showing an enlarged periphery of a toner conveyance surface shown in FIG. 2. It is the sectional side view which expanded further the conveyance wiring board shown by FIG. When the relative permittivity of the transport electrode overcoating layer in FIG. 6 is 4, the potential distribution and the direction of the electric field when the potential of the two left transport electrodes is +150 V and the potential of the two right transport electrodes is −150 V It is a figure which shows the analysis result by the finite element method of electric field strength. When the relative dielectric constant of the transport electrode overcoating layer in FIG. 6 is 300, the potential distribution and the direction of the electric field when the potential of the two left transport electrodes is +150 V and the potential of the two right transport electrodes is −150 V It is a figure which shows the analysis result by the finite element method of electric field strength. FIG. 7 is a graph showing an analysis result by an individual element method of a toner position in a toner conveyance direction (horizontal direction) when a traveling wave voltage is applied to a plurality of conveyance electrodes in FIG. 6. FIG. 7 is a graph showing an analysis result by an individual element method of toner velocity in a toner conveyance direction (horizontal direction) when traveling wave voltages are applied to a plurality of conveyance electrodes in FIG. 6. FIG. 7 is a graph showing an analysis result by an individual element method of a toner position in a height direction when a traveling wave voltage is applied to a plurality of transport electrodes in FIG. 6. 7 is a graph showing an analysis result by an individual element method of toner velocity in the height direction when traveling wave voltages are applied to a plurality of transport electrodes in FIG. 6. FIG. 6 is an enlarged side sectional view of the periphery of a developing position in the second embodiment of the toner supply apparatus shown in FIG. 2. FIG. 6 is an enlarged side sectional view of a periphery of a developing position in the third embodiment of the toner supply device shown in FIG. 2. FIG. 10 is an enlarged side cross-sectional view of a transport wiring board and a counter wiring board in the fourth embodiment of the toner supply device shown in FIG. 2. FIG. 10 is an enlarged side sectional view of a transport wiring substrate and a counter wiring substrate in a fifth embodiment of the toner supply device shown in FIG. 2. FIG. 10 is an enlarged side sectional view of a transport wiring board and a counter wiring board in a sixth embodiment of the toner supply device shown in FIG. 2. FIG. 10 is an enlarged side sectional view of a transport wiring substrate and a counter wiring substrate in a seventh embodiment of the toner supply device shown in FIG. 2. FIG. 10 is an enlarged side sectional view of a transport wiring substrate and a counter wiring substrate in an eighth embodiment of the toner supply device shown in FIG. 2. FIG. 20 is an enlarged side cross-sectional view of a transport wiring board and a counter wiring board in a ninth embodiment of the toner supply device shown in FIG. 2. FIG. 10 is an enlarged side sectional view of a transport wiring substrate and a counter wiring substrate in a tenth embodiment of the toner supply device shown in FIG. 2. FIG. 20 is an enlarged side sectional view of a transport wiring substrate and a counter wiring substrate in an eleventh embodiment of the toner supply device shown in FIG. 2.

  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 view showing a schematic configuration of a laser printer 1 which is an embodiment of an image forming apparatus of the present invention.

  Referring to FIG. 1, the laser printer 1 includes a paper transport mechanism 2, a photosensitive drum 3, a charger 4, a scanner unit 5, and a toner supply device 6.

  Sheet-like paper P is stored in a stacked state in a paper feed tray (not shown) provided in the laser printer 1. The paper transport mechanism 2 is configured to transport the paper P along a predetermined paper transport path.

  A latent image forming surface LS as a latent image forming surface (developer carrying surface) of the present invention is formed on the peripheral surface of the photosensitive drum 3 as an electrostatic latent image carrier (developer carrying member) of the present invention. ing.

  The latent image forming surface LS is formed as a cylindrical surface parallel to the main scanning direction (z-axis direction in the figure). The latent image forming surface LS is configured such that an electrostatic latent image based on a potential distribution can be formed.

  The photosensitive drum 3 is configured to be rotationally driven around a central axis C in a direction indicated by an arrow in the drawing (clockwise in FIG. 1). That is, the photosensitive drum 3 is configured such that the latent image forming surface LS can move along a predetermined movement direction, that is, a sub-scanning direction orthogonal to the main scanning direction.

  The “sub-scanning direction” is an arbitrary direction orthogonal to the main scanning direction. In general, the sub-scanning direction may be a direction that intersects a vertical line. That is, the sub-scanning direction can be a direction along the front-rear direction of the laser printer 1 (direction perpendicular to the paper width direction and the height direction: the x-axis direction in the figure).

  The charger 4 is disposed so as to face the latent image forming surface LS. The charger 4 is a corotron type or scorotron type charger, and is configured so that the latent image forming surface LS can be uniformly positively charged.

  The scanner unit 5 is configured to generate a laser beam LB modulated based on image data. That is, the scanner unit 5 is configured to generate a laser beam LB having a predetermined wavelength band in which light emission ON / OFF is controlled depending on the presence or absence of pixels.

  The scanner unit 5 is configured to image (expose) the generated laser beam LB at the scan position SP on the latent image forming surface LS. Here, the scan position SP is provided at a position downstream of the charger 4 in the rotation direction of the photosensitive drum 3 (direction indicated by the arrow in FIG. 1: clockwise in the drawing).

  Further, the scanner unit 5 moves (scans) the position at which the laser beam LB is formed on the latent image forming surface LS at a constant speed along the main scanning direction, thereby forming the latent image forming surface. An electrostatic latent image can be formed on the LS.

  The toner supply device 6 as the developer supply device of the present invention is disposed so as to face the photosensitive drum 3. The toner supply device 6 is configured to supply toner as a dry developer, which will be described later, to the latent image forming surface LS in a charged state at the development position DP. The detailed configuration of the toner supply device 6 will be described later.

<Configuration of each part of the laser printer>
Next, a specific configuration of each part of the laser printer 1 will be described.

<< paper transport mechanism >>
The sheet transport mechanism 2 includes a pair of registration rollers 21 and a transfer roller 22.

  The registration roller 21 is configured so that the paper P can be sent out between the photosensitive drum 3 and the transfer roller 22 at a predetermined timing.

  The transfer roller 22 is disposed so as to face the latent image forming surface LS, which is the outer peripheral surface of the photosensitive drum 3, at the transfer position TP with the paper P interposed therebetween. Further, the transfer roller 22 is configured to be rotationally driven in a direction (counterclockwise) indicated by an arrow in the drawing.

  The transfer roller 22 is connected to a bias power supply circuit (not shown). That is, a predetermined transfer bias voltage for transferring the toner (developer) adhered on the latent image forming surface LS to the paper P is applied between the transfer roller 22 and the photosensitive drum 3. Yes.

<< Photosensitive drum >>
FIG. 2 is an enlarged side sectional view of a portion where the photosensitive drum 3 and the toner supply device 6 shown in FIG. 1 face each other.

  Referring to FIG. 2, the photosensitive drum 3 includes a drum body 31 and a photosensitive layer 32.

  The drum body 31 is a cylindrical member having a central axis C parallel to the z axis, and is made of a metal such as aluminum. The drum body 31 is grounded.

  The photosensitive layer 32 is provided so as to cover the outer periphery of the drum body 31. The photosensitive layer 32 is composed of a positively chargeable photoconductive layer that exhibits electron conductivity when exposed to laser light having a predetermined wavelength.

  The latent image forming surface LS is configured by the outer peripheral surface of the photosensitive layer 32. That is, after being uniformly positively charged by the charger 4 (see FIG. 1), the laser beam LB is scanned at the scan position SP, thereby forming an electrostatic latent image LI having a positive charge pattern. Thus, the latent image forming surface LS (photosensitive layer 32) is configured.

<< Schematic Configuration of Toner Supply Device >>
Referring to FIG. 2, a toner box 61 forming a casing of the toner supply device 6 is a box-shaped member configured to store toner T as a fine dry developer in the inside thereof. In this embodiment, the toner T is a positively chargeable, non-magnetic one-component black toner.

  A top plate 61 a in the toner box 61 is disposed so as to be close to the photosensitive drum 3. The top plate 61a is a flat plate member having a rectangular shape in plan view, and is arranged in parallel with the horizontal plane.

  In the top plate 61a, a toner passage hole 61a1 is formed as a through hole through which the toner T can pass when moving from the inside of the toner box 61 toward the photosensitive layer 32 along the y-axis direction in the figure. The toner passage hole 61a1 has a long side having a length substantially the same as the width of the photosensitive layer 32 in the main scanning direction (z-axis direction in the drawing) in a plan view and the sub-scanning direction (x-axis direction in the drawing). ) And a rectangular shape having a short side parallel to.

  The toner passage hole 61a1 is provided in the vicinity of the position where the top plate 61a and the photosensitive layer 32 are closest to each other. Further, the toner passage hole 61a1 is formed such that the center in the sub-scanning direction (x-axis direction in the figure) is substantially coincident with the developing position DP.

  The bottom plate 61b in the toner box 61 is a rectangular plate-like member in plan view, and is disposed below the top plate 61a. The bottom plate 61b is disposed so as to be inclined in the y-axis direction as it goes in the x-axis direction in the figure.

  Four sides of the outer edge of the top plate 61a and the bottom plate 61b are surrounded by four side plates 61c (only two of the side plates 61c are shown in FIG. 2). The upper and lower ends of the four side plates 61c are integrally connected to the top plate 61a and the bottom plate 61b, so that the toner box 61 can be accommodated so as not to leak the toner T to the outside.

  At the deepest part of the toner box 61, a toner stirring part 61d is provided. The toner stirring unit 61d stirs the toner T stored in the toner box 61 (toner T before being transported in a predetermined toner transport direction TTD, which will be described later). It is configured to provide such fluidity.

  In the present embodiment, the toner stirring portion 61 d is configured by an impeller-like rotating body that is rotatably supported by a pair of side plates 61 c in the toner box 61.

<< Configuration of Toner Electric Field Carrier >>
Inside the toner box 61 is accommodated a toner electric field transport body 62 as a developer electric field transport device provided in the developer supply device of the present invention.

  The toner electric field transport body 62 has a toner transport surface TTS. The toner transport surface TTS as the developer transport surface of the present invention is formed in parallel with the main scanning direction (z-axis direction in the figure).

  The toner electric field transport body 62 is disposed so that the toner transport surface TTS and the latent image forming surface LS face each other at the closest position at the development position DP. That is, the toner electric field transport body 62 is arranged so that the closest position where the toner transport surface TTS and the latent image forming surface LS are closest is coincident with the development position DP.

  The toner electric field transport body 62 is a plate-like member having a predetermined thickness. The toner electric field transport body 62 is configured to transport the positively charged toner T in a predetermined toner transport direction TTD on the toner transport surface TTS. Here, the toner transport direction TTD is a direction parallel to the toner transport surface TTS and perpendicular to the main scanning direction (z-axis direction in the figure). That is, the toner transport direction TTD is a direction along the sub-scanning direction (x-axis direction in the drawing).

  The toner electric field transport body 62 includes a central component 62a, an upstream component 62b, and a downstream component 62c.

  The central component 62a has a long side that is substantially the same length as the width of the photosensitive drum 3 in the main scanning direction and has a short side that is longer than the diameter of the photosensitive drum 3, and is substantially rectangular in plan view. Is formed. The central component 62a is provided at a position such that the center in the sub-scanning direction (x-axis direction in the drawing) coincides with the center of the toner passage hole 61a1 in the sub-scanning direction. That is, the central component 62a is disposed substantially parallel to the top plate 61a so as to face the latent image forming surface LS across the toner passage hole 61a1.

  The upstream side component 62b extends obliquely downward from the upstream end of the central component 62a in the toner conveyance direction TTD to the upstream side in the toner conveyance direction TTD. In other words, the upstream side component 62b is provided as a plate-like member that is disposed so as to rise obliquely upward toward the central component 62a.

  The lower end part of the upstream side configuration part 62b is provided in the vicinity of the toner stirring part 61d. That is, even when the amount of toner T becomes small because the upstream end of the upstream component 62b in the toner transport direction TTD reaches the vicinity of the deepest portion of the toner box 61, the upstream component The upstream side component 62b is provided so that a part (lower end) of 62b is buried in the toner T.

  The downstream side component 62c extends further downstream from the downstream end of the central component 62a in the toner transport direction TTD and obliquely downward. That is, the downstream side component 62c is provided as a plate-like member arranged so as to descend obliquely downward as it moves away from the central component 62a.

  The lower end portion of the downstream side configuration portion 62 c is provided so as to be close to the bottom plate 61 b in the toner box 61. That is, the downstream end of the downstream component 62c in the toner transport direction TTD reaches the vicinity of the bottom plate 61b of the toner box 61 so that the toner T can smoothly flow back to the bottom plate 61b. A side component 62c is provided.

<First Embodiment of Toner Supply Device>
The configuration of the first embodiment of the present invention will be described below with reference to FIGS.

  FIG. 3 is an enlarged side sectional view of the periphery of the developing position DP in the first embodiment of the toner supply device 6 shown in FIG.

<< Conveyance wiring board >>
Referring to FIG. 3, the toner electric field transport body 62 includes a transport wiring board 63. The transport wiring board 63 is disposed so as to face the latent image forming surface LS across the top plate 61a and the toner passage hole 61a1 in the toner box 61.

  The transport wiring board 63 has the same configuration as the flexible printed wiring board as described below.

  The transport electrode 63a is formed as a linear wiring pattern having a longitudinal direction parallel to the main scanning direction (perpendicular to the sub-scanning direction). That is, the transport electrode 63a is made of a copper foil having a thickness of about several tens of μm. The plurality of transport electrodes 63a are arranged in parallel to each other. These transport electrodes 63a are arranged along the sub-scanning direction.

  Further, the transport electrode 63a is disposed along the toner transport surface TTS. That is, the transport electrode 63a is disposed in the vicinity of the toner transport surface TTS.

  Each of the plurality of transport electrodes 63a arranged in the sub-scanning direction is connected to the same power supply circuit every third.

  That is, the transfer electrode 63a connected to the power supply circuit VA, the transfer electrode 63a connected to the power supply circuit VB, the transfer electrode 63a connected to the power supply circuit VC, the transfer electrode 63a connected to the power supply circuit VD, and the power supply circuit VA. The connected transport electrodes 63a, the transport electrodes 63a connected to the power supply circuit VB, the transport electrodes 63a connected to the power supply circuit VC are arranged in order along the sub-scanning direction.

  Here, each power supply circuit VA thru | or VD is comprised so that the alternating voltage (carrier voltage) of a substantially identical waveform can be output. Further, the power supply circuits VA to VD are configured so that the phases of the waveforms of the voltages generated by the power supply circuits VA to VD are different by 90 °. That is, the voltage phase is delayed by 90 ° in order from the power supply circuit VA to the power supply circuit VD.

  These transport electrodes 63a are formed on the surface of a transport electrode support film 63b as a transport electrode support member of the present invention. The transport electrode support film 63b is a flexible film and is made of an insulating synthetic resin such as a polyimide resin.

  The transport electrode coating layer 63c as the transport electrode coating intermediate layer of the present invention is made of an insulating synthetic resin. The transport electrode coating layer 63c is provided so as to cover the surface of the transport electrode support film 63b on which the transport electrode 63a is provided and the transport electrode 63a.

  A transport electrode overcoating layer 63d as a transport electrode covering member of the present invention is provided on the transport electrode coating layer 63c. That is, the above-described transport electrode coating layer 63c is formed between the transport electrode overcoating layer 63d and the transport electrode 63a.

  The above-described toner transport surface TTS is made of the surface of the transport electrode overcoating layer 63d and is formed as a smooth surface with very few irregularities.

  In the present embodiment, the transport electrode overcoating layer 63d includes a high relative dielectric constant portion 63d1, an upstream low relative dielectric constant portion 63d2, and a downstream low relative dielectric constant portion 63d3.

  The high relative dielectric constant portion 63d1 is provided at a position corresponding to the counter area CA. Here, the facing area CA is an area in the toner electric field transport body 62 where the latent image forming surface LS and the toner transport surface TTS face each other across the toner passage hole 61a1. That is, the facing area CA is an area corresponding to the toner passage hole 61a1 (just below the toner passage hole 61a1).

  The upstream low relative dielectric constant portion 63d2 is provided at a position corresponding to the upstream portion TUA. Here, the upstream portion TUA is a region in the toner electric field transport body 62 on the upstream side in the toner transport direction TTD from the facing region CA. The upstream low relative permittivity portion 63d2 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63d1.

  The downstream low relative dielectric constant portion 63d3 is provided at a position corresponding to the downstream portion TDA. Here, the downstream portion TDA is a region in the toner electric field transport body 62 on the downstream side in the toner transport direction TTD from the facing region CA. The downstream low relative permittivity portion 63d3 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63d1.

  That is, the transport electrode overcoating layer 63d is configured such that the relative permittivity of the upstream portion TUA and the downstream portion TDA is lower than that of the counter area CA.

  The toner electric field transport body 62 also includes a transport substrate support member 64. The transport board support member 64 is made of a synthetic resin plate and is provided to support the transport wiring board 63 from below.

  Thus, the toner electric field transport body 62 generates a traveling-wave electric field along the sub-scanning direction by applying the transport voltage as described above to the transport electrodes 63a on the transport wiring board 63. Thus, the positively charged toner T can be transported in the toner transport direction TTD.

<< Opposite wiring board >>
Referring to FIG. 3, a counter wiring substrate 65 is mounted on the inner side surface (surface facing the space where the toner T is stored) of the top plate 61 a of the toner box 61. The counter wiring substrate 65 is disposed to face the toner transport surface TTS with a predetermined gap therebetween.

  The counter wiring board 65 has the same configuration as the above-described transport wiring board 63.

  Specifically, the counter wiring board 65 has a counter wiring board surface CS parallel to the main scanning direction. The counter wiring substrate surface CS is provided so as to face the toner transport surface TTS with a predetermined gap therebetween.

  A large number of counter electrodes 65a are provided along the counter wiring substrate surface CS. That is, the counter electrode 65a is disposed in the vicinity of the counter wiring substrate surface CS.

  The counter electrode 65a is formed as a linear wiring pattern having a longitudinal direction parallel to the main scanning direction (perpendicular to the sub-scanning direction). That is, the counter electrode 65a is made of a copper foil having a thickness of about several tens of μm. The plurality of counter electrodes 65a are arranged in parallel to each other. These counter electrodes 65a are arranged along the sub-scanning direction.

  In addition, every third counter electrode 65a arranged in the sub-scanning direction is connected to the same power supply circuit every third.

  These counter electrodes 65a are formed on the surface of a counter electrode support film 65b as a counter electrode support member of the present invention. The counter electrode support film 65b is a flexible film and is made of an insulating synthetic resin such as a polyimide resin.

  The counter electrode coating layer 65c as the counter electrode covering intermediate layer of the present invention is made of an insulating synthetic resin. The counter electrode coating layer 65c is provided so as to cover the surface of the counter electrode support film 65b on which the counter electrode 65a is provided and the counter electrode 65a.

  On the counter electrode coating layer 65c, a counter electrode overcoating layer 65d as a counter electrode covering member of the present invention is provided. That is, the above-described counter electrode coating layer 65c is formed between the counter electrode overcoating layer 65d and the counter electrode 65a.

  The counter wiring substrate surface CS described above is made of the surface of the counter electrode overcoating layer 65d, and is formed as a smooth surface with very few irregularities.

  In the present embodiment, the counter electrode overcoating layer 65d includes a high relative dielectric constant portion 65d1, an upstream low relative dielectric constant portion 65d2, and a downstream low relative dielectric constant portion 65d3.

  The high relative dielectric constant portion 65d1 is provided at a position corresponding to the counter area neighboring area CNA. Here, the counter area neighboring area CNA is an area in the counter wiring substrate 65 in the vicinity of the toner passage hole 61a1. That is, the counter area neighboring area CNA is an area in the counter wiring board 65 that is close to the counter area CA in the toner electric field transport body 62 (the transport wiring board 63).

  The upstream low relative dielectric constant portion 65d2 is provided at a position corresponding to the upstream portion CUA. Here, the upstream portion CUA is a region on the counter wiring substrate 65 on the upstream side in the toner transport direction TTD with respect to the counter region neighboring portion CNA. The upstream low relative dielectric constant portion 65d2 is made of a material having a relative dielectric constant lower than that of the counter area neighboring area CNA.

  The downstream low relative dielectric constant portion 65d3 is provided at a position corresponding to the downstream portion CDA. Here, the downstream portion CDA is a region on the counter wiring substrate 65 that is downstream in the toner transport direction TTD from the counter region neighboring portion CNA. The downstream low relative dielectric constant portion 65d3 is made of a material having a relative dielectric constant lower than that of the counter area neighboring area CNA.

  That is, the counter electrode overcoating layer 65d is configured such that the relative dielectric constant of the upstream portion CUA and the downstream portion CDA is lower than that of the counter area neighboring area CNA.

<Operation of laser printer>
Next, the operation of the laser printer 1 configured as described above will be described with reference to the drawings as appropriate.

<< Paper feeding action >>
First, referring to FIG. 1, the leading edge of the paper P stacked on a paper feed tray (not shown) is sent to the registration roller 21. The registration roller 21 corrects the skew of the paper P and adjusts the conveyance timing. Thereafter, the paper P is fed to the transfer position TP.

<< Carrying of toner image on latent image forming surface >>
As described above, while the sheet P is being conveyed toward the transfer position TP, an image of the toner T is carried on the latent image forming surface LS that is the peripheral surface of the photosensitive drum 3 as follows. .

<<< Formation of electrostatic latent image >>>
First, the latent image forming surface LS of the photosensitive drum 3 is uniformly charged positively by the charger 4.

  The latent image forming surface LS charged by the charger 4 is a scan which is a position facing (directly facing) the scanner unit 5 by the rotation of the photosensitive drum 3 in the direction (clockwise) indicated by the arrow in the drawing. It moves along the sub-scanning direction to the position SP.

  Referring to FIG. 2, a laser beam LB modulated based on image information is irradiated on the latent image forming surface LS at the scan position SP while being scanned along the main scanning direction. Depending on the modulation state of the laser beam LB, a portion where the positive charges on the latent image forming surface LS disappear is generated. Thereby, an electrostatic latent image LI having a positive charge pattern (image-like distribution) is formed on the latent image forming surface LS.

  The electrostatic latent image LI formed on the latent image forming surface LS is directed toward the developing position DP facing the toner supply device 6 by the rotation of the photosensitive drum 3 in the direction indicated by the arrow in the drawing (clockwise). Move.

<<< Conveyance and supply of charged toner >>>
Referring to FIG. 2, the toner T stored in the toner box 61 is fluidized by the toner stirring unit 61d. Specifically, the impeller constituting the toner stirring unit 61d rotates in the direction indicated by the arrow (clockwise) in the drawing.

  The operation of the toner agitating portion 61d causes friction between the toner T and the toner transport surface TTS (the surface of the transport electrode overcoating layer 63d made of synthetic resin in FIG. 3) in the upstream side configuration portion 62b. As a result, the toner T is positively charged.

  Here, as described above, the end portion on the upstream side (left side in the drawing) of the toner electric field transport body 62 (upstream configuration portion 62b) in the toner transport direction TTD is buried in the toner T. Therefore, the toner T stored in the toner box 61 is always supplied onto the toner transport surface TTS in the upstream portion TUA.

  In addition, a traveling wave-like transport voltage is applied to the plurality of transport electrodes 63 a in the toner electric field transport body 62. As a result, a predetermined traveling-wave electric field is formed on the toner transport surface TTS. By this traveling wave electric field, the positively charged toner T is transported along the toner transport direction TTD on the toner transport surface TTS.

  FIG. 4 is a graph showing waveforms of voltages generated by the power supply circuits VA to VD shown in FIG. FIG. 5 is an enlarged side sectional view showing the periphery of the toner transport surface TTS shown in FIG. In FIG. 3, the transport electrode 63a connected to the power supply circuit VA is shown as the transport electrode 63aA in FIG. The same applies to the transport electrodes 63aB to 63aD.

  Hereinafter, how the positively charged toner T is transported in the toner transport direction TTD on the toner transport surface TTS will be described with reference to FIGS. 4 and 5. FIG.

  As shown in FIG. 4, AC voltages having substantially the same waveform are output from the power supply circuits VA to VD so that the phase is delayed by 90 ° in order from the power supply circuit VA to the power supply circuit VD.

  At time t1 in FIG. 4, as shown in FIG. 5A, at the position between AB, which is the position between the transport electrode 63aA and the transport electrode 63aB, the direction opposite to the toner transport direction TTD ( An electric field EF1 in the direction opposite to x in FIG. 5 is formed.

  On the other hand, an electric field EF2 in the same direction as the toner transport direction TTD (the x direction in FIG. 5) is formed at the inter-CD position between the transport electrode 63aC and the transport electrode 63aD.

  Further, the position between BC, which is the position between the transport electrode 63aB and the transport electrode 63aC, and the position between DA, which is the position between the transport electrode 63aD and the transport electrode 63aA, are in the direction along the toner transport direction TTD. An 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 toner transport direction TTD 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 transport direction TTD.

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

  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.

  That is, the area where the toner T is collected moves on the toner transport surface TTS along the toner transport direction TTD with the passage of time.

  In this way, a voltage as shown in FIG. 4 is applied to each transport electrode 63a, whereby a traveling-wave electric field is formed on the toner transport surface TTS. As a result, the positively charged toner T is transported along the toner transport direction TTD while hopping in the y direction in the figure.

  Referring to FIG. 2, the toner T transporting operation by the counter wiring substrate 65 is the same as the toner T transporting operation by the transport wiring substrate 63 as described above.

  Here, FIG. 6 to FIG. 12 show the results of computer simulation of the difference in electric field strength and toner behavior depending on the relative dielectric constant of the transport electrode overcoating layer 63d.

FIG. 6 is an enlarged side sectional view of the transport wiring board 63 shown in FIG. The numbers on the vertical and horizontal axes in FIG. 6 indicate the position (distance), and the unit is 10 ⁻⁴ m.

  The transport electrode 63a has a thickness of 18 μm and an electrode width (width in the sub-scanning direction) of 100 μm. The interelectrode pitch between the transport electrodes 63a was 100 μm.

  The transport electrode support film 63b had a thickness of 25 μm and a relative dielectric constant of 5.

  The transport electrode coating layer 63c had a maximum thickness (thickness in a portion where the transport electrode 63a is not provided) of 43 μm and a relative dielectric constant of 2.3.

  The transport electrode overcoating layer 63d had a thickness of 12.5 μm and a relative dielectric constant of 4 or 300.

  Under such conditions, electric field analysis by the finite element method and particle behavior analysis by the individual element method were performed.

  7 and FIG. 8 show a finite number of potential distributions, electric field directions, and electric field strengths when the potential of the two left transport electrodes 63a in FIG. 6 is + 150V and the potential of the two right transport electrodes 63a is −150V. It is a figure which shows the analysis result by an element method. Here, the potential distribution is indicated by the color depth (the darker the absolute value of the potential value is greater), the direction of the electric field is indicated by the direction of the arrow, and the electric field strength is indicated by the length of the arrow. It is assumed that

  FIG. 7 shows a case where the relative dielectric constant of the transport electrode overcoating layer 63d in FIG. FIG. 8 shows a case where the relative dielectric constant of the transport electrode overcoating layer 63d in FIG.

  As is apparent from FIGS. 6 to 8, the higher the relative dielectric constant of the transport electrode overcoating layer 63d, the smaller the electric field strength on the toner transport surface TTS in both the toner transport direction TTD and the height direction. .

  FIG. 9 is a graph showing the analysis result by the individual element method of the toner position in the toner transport direction TTD (horizontal direction) when a traveling wave voltage is applied to the plurality of transport electrodes 63a in FIG. FIG. 10 is a graph showing an analysis result by the individual element method of the toner speed in the toner transport direction TTD (horizontal direction) when a traveling wave voltage is applied to the plurality of transport electrodes 63a in FIG.

  FIG. 11 is a graph showing the analysis result by the individual element method of the toner position in the height direction when a traveling wave voltage is applied to the plurality of transport electrodes 63a in FIG. FIG. 12 is a graph showing the analysis result by the individual element method of the toner velocity in the height direction when a traveling wave voltage is applied to the plurality of transport electrodes 63a in FIG.

Here, in FIG. 9 to FIG. 12, “Frame Number” on the horizontal axis corresponds to the time axis (1 Frame is 40 μsec).

Further, in the simulations of FIGS. 9 to 12, 300 spherical toners having a radius of 10 μm (100 × 1 row × 3) are within a width of 1 mm along the toner transport direction TTD on the toner transport surface TTS. 11) The average position and average speed of these 300 toners were obtained (therefore, Frame Number = 0, Position = 0.5 mm in FIG. 9, and FIG. 11). (Position≈25 μm).

The toner density was 1.2 g / cc, and the charge amount was 30 μC / g (the charge amount per toner particle was 1.89 × 10 ⁻¹⁴ C).

  Furthermore, the frequency of the carrier voltage was 800 Hz.

  As apparent from FIGS. 6, 9, and 10, the higher the relative dielectric constant of the transport electrode overcoating layer 63d, the lower the toner transport speed in the toner transport direction TTD. Further, the higher the relative dielectric constant of the transport electrode overcoating layer 63d, the smaller the fluctuation of the toner transport speed in the toner transport direction TTD. That is, the toner conveyance speed is stabilized.

  Further, as apparent from FIGS. 6, 11, and 12, the higher the relative dielectric constant of the transport electrode overcoating layer 63d, the higher the average position of the toner in the height direction. That is, the higher the relative dielectric constant of the transport electrode overcoating layer 63d, the more the toner can float from the toner transport surface TTS.

  Referring to FIG. 2, the positively charged toner T moves up the inclined toner conveyance surface TTS in the upstream side component 62b by the traveling wave electric field formed on the toner conveyance surface TTS as described above. Go. Then, the toner T reaches the central component 62a.

  In addition to the traveling-wave electric field caused by the transport wiring board 63 as described above, the traveling-wave electric field caused by the counter wiring board 65 also acts on the toner T that has reached the central component 62a.

  Referring to FIG. 3, the toner T transported to the central component 62a is transported in the toner transport direction TTD, thereby reaching a position corresponding to the facing area proximity portion CNA (directly below the facing area proximity portion CNA).

  Here, the counter electrode overcoating layer 65d (high relative dielectric constant portion 65d1) in the counter area neighboring area CNA is more dielectric than the counter electrode overcoating layer 65d (upstream low relative dielectric constant section 65d2) in the upstream section CUA. The rate is high.

  Therefore, the strength of the traveling wave electric field along the toner conveyance direction TTD by the counter wiring substrate 65 is lower in the counter area neighboring area CNA than in the upstream area CUA. As a result, the transport speed of the toner T in the toner transport direction TTD is reduced.

  The toner T decelerated by the counter area neighboring area CNA then reaches the counter area CA. The counter wiring substrate 65 is not provided in the counter area CA. Therefore, in this counter area CA, the toner T is transported exclusively by a traveling wave electric field generated by the transport wiring board 63.

  Here, the transport electrode overcoating layer 63d (high relative dielectric constant portion 63d1) in the facing area CA has a relative dielectric constant higher than that of the transport electrode overcoating layer 63d (upstream low relative dielectric constant portion 63d2) in the upstream portion TUA. Is high.

  Therefore, the intensity of the traveling wave electric field along the toner transport direction TTD by the transport wiring board 63 is lower in the counter area CA than in the upstream area TUA. Thereby, the transport speed of the toner T in the toner transport direction TTD is further reduced.

  The toner T that has passed through the counter area CA then reaches a position corresponding to the counter area neighboring area CNA. Here, the traveling wave electric field by the counter wiring substrate 65 again acts on the toner T.

  The toner T that has passed through the counter area CA reaches the downstream portion TDA. Here, the transport electrode overcoating layer 63d (downstream low relative dielectric constant portion 63d3) in the downstream portion TDA is more specific than the transport electrode overcoating layer 63d (high relative dielectric constant portion 63d1) in the counter area CA. Is low. Therefore, the strength of the traveling wave electric field along the toner transport direction TTD by the transport wiring board 63 is higher in the downstream portion TDA than in the counter area CA.

  As a result, the toner T that has passed through the counter area CA is accelerated more than in the counter area CA.

  When the toner T is further transported in the toner transport direction TTD, the toner T reaches the downstream portion CDA.

  Here, the counter electrode overcoating layer 65d (downstream low relative dielectric constant portion 65d3) in the downstream portion CDA has a dielectric constant higher than that of the counter electrode overcoating layer 65d (high relative dielectric constant portion 65d1) in the counter area neighboring portion CNA. The rate is low.

  Therefore, the intensity of the traveling wave electric field along the toner conveyance direction TTD by the counter wiring substrate 65 is higher in the downstream area CDA than in the counter area neighboring area CNA. Thereby, the transport speed of the toner T in the toner transport direction TTD is accelerated.

  Referring to FIG. 2, the toner T that has passed through the counter area CA is conveyed from the central component 62a toward the downstream component 62c. Then, the toner T falls downward from the downstream side configuration part 62 c, thereby returning to the bottom of the toner box 61.

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

  In the vicinity of the development position DP, the electrostatic latent image LI formed on the latent image forming surface LS is developed with the toner T. That is, the toner T adheres to the portion on the latent image forming surface LS where the positive charge in the electrostatic latent image LI has disappeared. As a result, an image of the toner T (hereinafter referred to as “toner image”) is carried on the latent image forming surface LS.

<< Transfer of toner image from latent image forming surface to paper >>
Referring to FIG. 1, the toner image carried on the latent image forming surface LS of the photosensitive drum 3 as described above has a latent image forming surface LS in the direction (clockwise) indicated by the arrow in the drawing. Is conveyed toward the transfer position TP. At the transfer position TP, the toner image is transferred onto the paper P from the latent image forming surface LS.

<Operation / Effects of Configuration of First Embodiment>
2 and FIG. 3, in the configuration of the present embodiment, the transport electrode overcoating layer 63d has an upstream side (upstream portion TUA) and a downstream side (downstream portion) in the toner transport direction TTD with respect to the counter area CA. TDA) is configured to have a lower relative dielectric constant.

  Therefore, when a traveling wave-like transport voltage is applied to the transport electrode 63a, as described above, the upstream portion TUA and the downstream portion TDA have an electric field in the space near the toner transport surface TTS rather than the counter area CA. The strength of is increased.

  According to such a configuration, a strong electric field is generated in the upstream side configuration part 62 b (upstream part TUA) buried in the toner T stored in the toner box 61. Due to this strong electric field, a large acceleration is exerted on the toner T in the upper end portion of the toner T stored in the toner box 61 and in the vicinity of the upstream side configuration portion 62b (hereinafter referred to as “toner conveyance start position”). Given.

  Therefore, a large force is applied in the toner transport direction TTD to the toner T at the toner transport start position that hardly moves in the toner transport direction TTD. Therefore, the toner T can be transported in the toner transport direction TTD from the toner transport start position.

  In such a configuration, the electric field strength in the space near the toner transport surface TTS is low in the counter area CA. Thereby, the leakage of the toner T from the toner passage hole 61a1 can be suppressed. Therefore, the adhesion of the toner T to the white background portion (the portion where the pixels of the toner T are not formed) on the latent image forming surface LS of the photosensitive drum 3, that is, “white background fogging” can be effectively suppressed.

  In this configuration, as described above, the toner T is slightly lifted from the toner transport surface TTS in the facing area CA. Therefore, the restraining force (adhesive force such as mirror image force or van der Waals force) on the toner transport surface TTS with respect to the toner T at the development position DP can be relaxed satisfactorily. Therefore, the selective adhesion of the toner T to the latent image forming surface LS according to the pattern of positive charges in the electrostatic latent image LI can be performed with good responsiveness.

  As described above, according to the configuration of the present embodiment, the toner T can be adhered to the latent image forming surface LS at the development position DP (development of the electrostatic latent image LI by the toner T).

  Further, the conveyance of the toner T can be decelerated in the facing area CA. As a result, the density of toner T increases in the counter area CA. Therefore, unevenness in the amount of toner T present in the toner transport direction TTD can be effectively suppressed.

  In addition, according to such a configuration, the toner T that has passed through the counter area CA can be accelerated in a direction away from the counter area CA toward the downstream side. As a result, the retention of a large amount of toner T in the counter area CA can be suppressed. Therefore, the above-mentioned “white background fog” can be effectively suppressed. In addition, the toner T that has passed through the counter area CA can quickly recirculate into the toner box 61.

  As described above, according to such a configuration, the toner T transport state in the toner transport direction TTD by the toner electric field transport body 62 can be appropriately set. Therefore, according to such a configuration, image formation with the toner T can be performed better.

  Referring to FIGS. 2 and 3, in the configuration of the present embodiment, the counter electrode overcoating layer 65d has an upstream side (upstream portion CUA) and a downstream side (upstream portion CUA) in the toner transport direction TTD with respect to the counter area neighboring portion CNA. The downstream portion CDA) is configured to have a lower relative dielectric constant.

  Therefore, when the traveling wave-like transport voltage is applied to the counter electrode 65a, as described above, the upstream CUA and the downstream CDA are closer to the space near the toner transport surface TTS than the counter area neighboring area CNA. The electric field strength at is increased.

  According to this configuration, the strength of the electric field in the space near the counter wiring substrate surface CS is reduced in the counter area neighboring area CNA. Therefore, the conveyance of the toner T can be decelerated at the counter area neighboring area CNA. As a result, the density of toner T increases in the counter area neighboring area CNA. Therefore, unevenness in the amount of toner T present in the toner transport direction TTD can be effectively suppressed.

  In addition, according to such a configuration, the toner T that has passed through the counter area neighboring area CNA can be accelerated in a direction to leave the counter area neighboring area CNA toward the downstream side. As a result, the retention of a large amount of toner T in the counter area neighboring area CNA can be suppressed. Therefore, the toner T that has passed through the counter area neighboring area CNA can quickly recirculate into the toner box 61.

  Thus, according to this configuration, the transport state of the toner T in the toner transport direction TTD by the counter wiring substrate 65 can be set appropriately. Therefore, according to such a configuration, image formation with the toner T can be performed better.

  Referring to FIGS. 2 and 3, in the configuration of the present embodiment, the opposed area proximity portion CNA is provided on the upstream side and the downstream side in the toner conveyance direction TTD of the opposed area CA. That is, the counter area CA is between the counter area neighboring area CNA upstream of the toner passing hole 61a1 in the toner conveying direction TTD and the counter area neighboring area CNA downstream of the toner passing hole 61a1 in the toner conveying direction TTD. Is provided.

  As a result, the toner transport surface TTS in the toner electric field transport body 62 (central component 62a) and the counter wiring substrate surface CS in the counter wiring substrate 65 are opposed to each other with a predetermined gap therebetween as follows. Can be configured.

  That is, (a) a region where the upstream portion CUA (upstream low relative dielectric constant portion 65d2) of the counter wiring substrate 65 and the upstream portion TUA (upstream low relative dielectric constant portion 63d2) of the toner electric field transport body 62 face each other. (B) a region where the opposed region neighboring portion CNA (high relative dielectric constant portion 65d1) in the opposed wiring substrate 65 and the upstream portion TUA (upstream low relative dielectric constant portion 63d2) in the toner electric field transport body 62 are opposed to each other; (C) a region where the toner passage hole 61a1 and the opposing region CA (high relative dielectric constant portion 63d1) of the toner electric field transport body 62 are opposed to each other, (d) an opposing region adjacent portion CNA (high relative dielectric constant) of the counter wiring substrate 65 Area 65d1) and the downstream portion TDA (downstream low relative dielectric constant portion 63d3) of the toner electric field transport body 62 are opposed to each other, (e) the downstream portion CD of the counter wiring substrate 65. The regions where the (downstream low relative dielectric constant portion 65d3) and the downstream portion TDA (downstream low relative dielectric constant portion 63d3) of the toner electric field transport body 62 face each other are arranged in this order in the toner transport direction TTD. obtain.

  In such a configuration, the electric field strength decreases from (a) through (b) to (c). In addition, the electric field strength increases from the above (c) to (e) through (d).

  According to this configuration, the toner T is smoothly decelerated from (a) through (b) to (c), and from (c) through (d) to (e). Accordingly, the toner T can be smoothly accelerated.

<Second Embodiment of Toner Supply Apparatus>
The configuration of the second embodiment of the present invention will be described below with reference to FIG.

  In the following description of the second embodiment, the same reference numerals as those in the above embodiment may be used for members having the same configuration and function as those described in the above embodiment. As for the description of such members, the description in the above-described embodiment can be used within a technically consistent range (the same applies to the third and later embodiments described later).

  FIG. 13 is an enlarged side sectional view of the periphery of the developing position DP in the second embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 13, in this embodiment, instead of the transport electrode overcoating layer 63d, the transport electrode coating layer 63c includes a high relative dielectric constant portion 63c1, an upstream low relative dielectric constant portion 63c2, and a downstream low ratio. A dielectric constant portion 63c3 is provided.

  The high relative dielectric constant portion 63c1 is provided at a position corresponding to the counter area CA. The upstream low relative dielectric constant portion 63c2 is provided at a position corresponding to the upstream portion TUA. The downstream low relative dielectric constant portion 63c3 is provided at a position corresponding to the downstream portion TDA.

  The upstream low relative permittivity portion 63c2 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63c1. The downstream low relative permittivity portion 63c3 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63c1. That is, the transport electrode coating layer 63c is configured such that the relative permittivity is lower in the upstream portion TUA and the downstream portion TDA than in the counter area CA.

  In this embodiment, instead of the counter electrode overcoating layer 65d, the counter electrode coating layer 65c includes a high relative dielectric constant portion 65c1, an upstream low relative dielectric constant portion 65c2, and a downstream low relative dielectric constant portion. 65c3.

  The high relative dielectric constant portion 65c1 is provided at a position corresponding to the counter area neighboring area CNA. The upstream low relative dielectric constant portion 65c2 is provided at a position corresponding to the upstream portion CUA. The downstream low relative dielectric constant portion 65c3 is provided at a position corresponding to the downstream portion CDA.

  The upstream low relative dielectric constant portion 65c2 is made of a material having a relative dielectric constant lower than that of the counter area neighboring area CNA. The downstream low relative dielectric constant portion 65c3 is made of a material having a relative dielectric constant lower than that of the counter area neighboring area CNA. That is, the counter electrode coating layer 65c is configured such that the relative permittivity of the upstream portion CUA and the downstream portion CDA is lower than that of the counter area neighboring area CNA.

  Also with this configuration, the same operations and effects as those of the first embodiment described above can be obtained.

<Third Embodiment of Toner Supply Device>
The configuration of the third embodiment of the present invention will be described below with reference to FIG.

  FIG. 14 is an enlarged side sectional view of the periphery of the development position DP in the third embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 14, in this embodiment, the transport electrode overcoating layer 63d (see FIG. 13) in the configuration of the above-described second embodiment is omitted. That is, in this embodiment, the transport electrode coating member 63c of the present invention is configured by the transport electrode coating layer 63c.

  In the present embodiment, the counter electrode overcoating layer 65d (see FIG. 13) in the configuration of the above-described second embodiment is omitted. That is, in this embodiment, the counter electrode coating member of the present invention is configured by the counter electrode coating layer 65c.

  Even with this configuration, the same operations and effects as those of the above-described embodiments can be obtained.

<Fourth Embodiment of Toner Supply Apparatus>
The configuration of the fourth embodiment of the present invention will be described below with reference to FIG.

  FIG. 15 is an enlarged side sectional view of the transport wiring substrate 63 and the counter wiring substrate 65 in the fourth embodiment of the toner supply device 6 shown in FIG.

  Here, in FIG. 15, for convenience of explanation, illustration of a part of the transport wiring board 63 is omitted, and the central constituent part 62a, the upstream constituent part 62b, and the downstream side of the transport wiring board 63 are omitted. The components 62c are illustrated as being arranged straight (the same applies to FIG. 16 and subsequent figures).

  Referring to FIG. 15, the transport electrode overcoating layer 63 d in this embodiment includes a high relative dielectric constant portion 63 d 1, an upstream low relative dielectric constant portion 63 d 2, a downstream low relative dielectric constant portion 63 d 3, and an upstream intermediate ratio. A dielectric constant part 63d4 and a downstream intermediate relative dielectric constant part 63d5 are provided.

  The high relative dielectric constant portion 63d1 is provided at a position corresponding to the counter area CA.

  The upstream low relative dielectric constant portion 63d2 is provided at a position corresponding to the most upstream area TMUA. Here, the most upstream area TMUA is an area in the toner electric field transport body 62 on the most upstream side in the toner transport direction TTD. That is, the most upstream part TMUA corresponds to the most upstream part in the toner transport direction TTD of the upstream side constituent part 62b. The upstream low relative permittivity portion 63d2 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63d1.

  An upstream intermediate relative dielectric constant portion 63d4 is provided at a position corresponding to the upstream intermediate portion TUIA between the most upstream area TMUA and the counter area CA. The upstream intermediate relative permittivity portion 63d4 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 63d1 and the upstream low relative permittivity portion 63d2.

  The downstream low relative dielectric constant portion 63d3 is provided at a position corresponding to the most downstream portion TMDA. Here, the most downstream portion TMDA is a region in the toner electric field transport body 62 on the most downstream side in the toner transport direction TTD. That is, the most downstream portion TMDA corresponds to the most downstream portion of the downstream side configuration portion 62c in the toner transport direction TTD. The downstream low relative permittivity portion 63d3 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63d1.

  A downstream intermediate relative dielectric constant portion 63d5 is provided at a position corresponding to the downstream intermediate portion TDIA between the most downstream portion TMDA and the counter area CA. The downstream intermediate relative permittivity portion 63d5 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 63d1 and the downstream low relative permittivity portion 63d3.

  That is, the transport electrode overcoating layer 63d is configured such that the relative dielectric constant gradually increases from the most upstream area TMUA toward the counter area CA via the upstream intermediate section TUIA. Further, the transport electrode overcoating layer 63d is configured such that the relative dielectric constant gradually decreases from the counter area CA through the downstream intermediate part TDIA to the most downstream part TMDA.

  The counter electrode overcoating layer 65d in the present embodiment includes a high relative dielectric constant portion 65d1, an upstream low relative dielectric constant portion 65d2, a downstream low relative dielectric constant portion 65d3, and an upstream intermediate relative dielectric constant portion 65d4. And a downstream intermediate relative dielectric constant portion 65d5.

  The high relative dielectric constant portion 65d1 is provided at a position corresponding to the counter area neighboring area CNA.

  The upstream low relative dielectric constant portion 65d2 is provided at a position corresponding to the most upstream area CMUA. Here, the most upstream area CMUA is an area in the counter wiring substrate 65 on the most upstream side in the toner transport direction TTD. The upstream low relative dielectric constant portion 65d2 is made of a material having a relative dielectric constant lower than that of the high relative dielectric constant portion 65d1.

  An upstream intermediate relative dielectric constant portion 65d4 is provided at a position corresponding to the upstream intermediate portion CUIA between the most upstream portion CMUA and the counter area neighboring portion CNA. The upstream intermediate relative permittivity portion 65d4 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 65d1 and the upstream low relative permittivity portion 65d2.

  The downstream low relative dielectric constant portion 65d3 is provided at a position corresponding to the most downstream portion CMDA. Here, the most downstream area CMDA is an area on the counter wiring board 65 which is the most downstream side in the toner transport direction TTD. The downstream low relative permittivity portion 65d3 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 65d1.

  A downstream intermediate relative dielectric constant portion 65d5 is provided at a position corresponding to the downstream intermediate portion CDIA between the most downstream portion CMDA and the counter area neighboring portion CNA. The downstream intermediate relative permittivity portion 65d5 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 65d1 and the downstream low relative permittivity portion 65d3.

  That is, the counter electrode overcoating layer 65d is configured such that the relative dielectric constant gradually increases from the most upstream area CMUA to the counter area neighboring area CNA through the upstream intermediate area CUIA. Further, the counter electrode overcoating layer 65d is configured such that the relative dielectric constant gradually decreases from the counter area neighboring area CNA to the downstream intermediate area CDIA toward the most downstream area CMDA.

  According to the toner electric field transport body 62 (transport wiring board 63) of the present embodiment having such a configuration, the electric field strength decreases from the most upstream area TMUA toward the counter area CA through the upstream intermediate section TUIA.

  Therefore, the toner T is favorably accelerated at the most upstream area TMUA. As a result, the toner T can be satisfactorily supplied toward the counter area CA. Further, the toner T is smoothly decelerated from the most upstream area TMUA toward the counter area CA through the upstream intermediate area TUIA. As a result, the density of the toner T increases in the counter area CA. Therefore, unevenness in the amount of toner T present in the toner transport direction TTD can be effectively suppressed.

  Further, according to the toner electric field transport body 62 (transport wiring board 63) of the present embodiment having such a configuration, the electric field strength increases from the counter area CA through the downstream intermediate section TDIA to the most downstream section TMDA. .

  Therefore, the toner T is smoothly accelerated so as to leave the counter area CA along the toner transport direction TTD. As a result, a large amount of toner T staying in the counter area CA can be suppressed. In addition, the toner T that has passed through the counter area CA can quickly recirculate into the toner box 61.

  According to the counter wiring substrate 65 of the present embodiment having such a configuration, the electric field strength decreases as it goes from the most upstream area CMUA to the upstream intermediate section TUIA toward the counter area neighboring area CNA.

  Therefore, the toner T is favorably accelerated in the most upstream area CMUA. As a result, the toner T can be satisfactorily supplied toward the counter area CA. Further, the toner T is smoothly decelerated from the most upstream area TMUA toward the counter area CA through the upstream intermediate area CUIA. As a result, the density of the toner T increases in the counter area CA. Therefore, unevenness in the amount of toner T present in the toner transport direction TTD can be effectively suppressed.

  Further, according to the counter wiring substrate 65 of this embodiment having such a configuration, the electric field strength increases from the counter area neighboring area CNA through the downstream intermediate section CDIA to the most downstream area CMDA.

  Therefore, the toner T is smoothly accelerated so as to leave the counter area CA and the counter area neighboring area CNA along the toner transport direction TTD. As a result, the retention of a large amount of toner T in the counter area CA and the counter area neighboring area CNA can be suppressed. In addition, the toner T that has passed through the counter area CA can quickly recirculate into the toner box 61.

  According to the toner electric field transport body 62 (transport wiring board 63) and the counter wiring board 65 of the present embodiment having such a configuration, the following areas (a) to (i) are arranged in this order in the toner transport direction TTD. Can be done.

  (A) The region where the most upstream area CMUA (upstream low relative dielectric constant portion 65d2) in the counter wiring substrate 65 and the most upstream area TMUA (upstream low relative dielectric constant portion 63d2) in the toner electric field transport body 62 are opposed to each other. .

  (B) The most upstream area CMUA (upstream low relative dielectric constant section 65d2) of the counter wiring substrate 65 and the upstream intermediate section TUIA (upstream intermediate relative dielectric constant section 63d4) of the toner electric field transport body 62 are opposed to each other. region.

  (C) The upstream intermediate portion CUIA (upstream intermediate relative permittivity portion 65d4) in the counter wiring board 65 and the upstream intermediate portion TUIA (upstream intermediate relative permittivity portion 63d4) in the toner electric field transport body 62 face each other. Area.

  (D) A region in which the counter region neighboring portion CNA (high relative dielectric constant portion 65d1) in the counter wiring substrate 65 and the upstream intermediate portion TUIA (upstream intermediate relative dielectric constant portion 63d4) in the toner electric field transport body 62 are opposed to each other. .

  (E) A region where the toner passage hole 61a1 and the facing region CA (high relative dielectric constant portion 63d1) of the toner electric field transport body 62 face each other.

  (F) A region where the opposed region neighboring portion CNA (high relative dielectric constant portion 65d1) of the opposed wiring substrate 65 and the downstream intermediate portion TDIA (downstream intermediate relative dielectric constant portion 63d5) of the toner electric field transport body 62 are opposed to each other. .

  (G) The downstream intermediate portion CDIA (downstream intermediate relative dielectric constant portion 65d5) of the counter wiring substrate 65 and the downstream intermediate portion TDIA (downstream intermediate relative dielectric constant portion 63d5) of the toner electric field transport body 62 face each other. Area.

  (H) The most downstream portion CMDA (downstream low relative dielectric constant portion 65d3) of the counter wiring substrate 65 and the downstream intermediate portion TDIA (downstream intermediate relative dielectric constant portion 63d5) of the toner electric field transport body 62 are opposed to each other. region.

  (I) Region where the most downstream portion CMDA (downstream low relative dielectric constant portion 65d3) in the counter wiring substrate 65 and the most downstream portion TMDA (downstream low relative dielectric constant portion 63d3) in the toner electric field transport body 62 are opposed to each other. .

  In such a configuration, the electric field strength decreases as going from (a) to (e) described above. Further, the electric field strength increases from the above (e) to (i).

  According to this configuration, the toner T is smoothly decelerated as it goes from (a) to (e), and the toner T is smoothly accelerated as it goes from (e) to (i). obtain.

  Thus, according to the toner electric field transport body 62 (transport wiring board 63) and the counter wiring board 65 of the present embodiment, the acceleration and deceleration of the toner T can be performed more smoothly.

<Fifth Embodiment of Toner Supply Apparatus>
The configuration of the fifth embodiment of the present invention will be described below with reference to FIG.

  FIG. 16 is an enlarged side sectional view of the transport wiring board 63 and the counter wiring board 65 in the fifth embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 16, in this embodiment, instead of the transport electrode overcoating layer 63d in FIG. 15, the transport electrode coating layer 63c includes a high relative dielectric constant portion 63c1, an upstream low relative dielectric constant portion 63c2, and a downstream side. A low relative dielectric constant portion 63c3, an upstream intermediate relative dielectric constant portion 63c4, and a downstream intermediate relative dielectric constant portion 63c5 are provided.

  The upstream low relative dielectric constant portion 63c2 is provided at a position corresponding to the most upstream area TMUA. The upstream low relative permittivity portion 63c2 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63c1.

  An upstream intermediate relative dielectric constant portion 63c4 is provided at a position corresponding to the upstream intermediate portion TUIA between the most upstream area TMUA and the counter area CA. The upstream intermediate relative permittivity portion 63c4 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 63c1 and the upstream low relative permittivity portion 63c2.

  The downstream low relative dielectric constant portion 63c3 is provided at a position corresponding to the most downstream portion TMDA. The downstream low relative permittivity portion 63c3 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 63c1.

  A downstream intermediate relative dielectric constant portion 63c5 is provided at a position corresponding to the downstream intermediate portion TDIA between the most downstream portion TMDA and the counter area CA. The downstream intermediate relative permittivity portion 63c5 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 63c1 and the downstream low relative permittivity portion 63c3.

  That is, the transport electrode coating layer 63c is configured such that the relative dielectric constant decreases from the most upstream area TMUA toward the counter area CA via the upstream intermediate section TUIA. Further, the transport electrode coating layer 63c is configured so that the relative dielectric constant increases from the counter area CA through the downstream intermediate part TDIA to the most downstream part TMDA.

  Further, in this embodiment, instead of the counter electrode overcoating layer 65d in FIG. 15, the counter electrode coating layer 65c includes a high relative dielectric constant portion 65c1, an upstream low relative dielectric constant portion 65c2, and a downstream low ratio. A dielectric constant portion 65c3, an upstream intermediate relative dielectric constant portion 65c4, and a downstream intermediate relative dielectric constant portion 65c5 are provided.

  The high relative dielectric constant portion 65c1 is provided at a position corresponding to the counter area neighboring area CNA.

  The upstream low relative dielectric constant portion 65c2 is provided at a position corresponding to the most upstream area CMUA. The upstream low relative dielectric constant portion 65c2 is made of a material having a relative dielectric constant lower than that of the high relative dielectric constant portion 65c1.

  An upstream intermediate relative dielectric constant portion 65c4 is provided at a position corresponding to the upstream intermediate portion CUIA between the most upstream portion CMUA and the counter area neighboring portion CNA. The upstream intermediate relative permittivity portion 65c4 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 65c1 and the upstream low relative permittivity portion 65c2.

  The downstream low relative dielectric constant portion 65c3 is provided at a position corresponding to the most downstream portion CMDA. The downstream low relative permittivity portion 65c3 is made of a material having a relative permittivity lower than that of the high relative permittivity portion 65c1.

  A downstream intermediate relative dielectric constant portion 65c5 is provided at a position corresponding to the downstream intermediate portion CDIA between the most downstream portion CMDA and the counter area neighboring portion CNA. The downstream intermediate relative permittivity portion 65c5 is made of a material whose relative permittivity is intermediate between the high relative permittivity portion 65c1 and the downstream low relative permittivity portion 65c3.

  That is, the counter electrode coating layer 65c is configured such that the relative dielectric constant gradually increases from the most upstream area CMUA toward the counter area neighboring area CNA through the upstream intermediate area CUIA. The counter electrode coating layer 65c is configured such that the relative dielectric constant gradually decreases from the counter area neighboring area CNA to the downstream intermediate area CDIA through the downstream intermediate area CDIA.

  Even with this configuration, the same operations and effects as in the fourth embodiment described above can be obtained.

<Sixth Embodiment of Toner Supply Apparatus>
The configuration of the sixth embodiment of the present invention will be described below with reference to FIG.

  FIG. 17 is an enlarged side sectional view of the periphery of the development position DP in the sixth embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 17, in this embodiment, the transport electrode overcoating layer 63d (see FIG. 16) in the configuration of the above-described fifth embodiment is omitted. That is, in this embodiment, the transport electrode coating member 63c of the present invention is configured by the transport electrode coating layer 63c.

  In the present embodiment, the counter electrode overcoating layer 65d (see FIG. 16) in the configuration of the above-described second embodiment is omitted. That is, in this embodiment, the counter electrode coating member of the present invention is configured by the counter electrode coating layer 65c.

  Even with this configuration, the same functions and effects as those of the fourth and fifth embodiments described above can be obtained.

<Seventh Embodiment of Toner Supply Device>
The configuration of the seventh embodiment of the present invention will be described below with reference to FIG.

  FIG. 18 is an enlarged side sectional view of the transport wiring board 63 and the counter wiring board 65 in the seventh embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 18, in the present embodiment, the transport electrode overcoating layer 63 d is configured to increase in thickness from the most upstream area TMUA to the upstream intermediate area TUIA toward the counter area CA. Further, the transport electrode overcoating layer 63d is configured to become thinner from the counter area CA through the downstream intermediate part TDIA toward the most downstream part TMDA.

  In the present embodiment, the counter electrode overcoating layer 65d is configured to increase in thickness from the most upstream area CMUA to the counter area neighboring area CNA through the upstream intermediate area CUIA. Further, the counter electrode overcoating layer 65d is configured to become thinner from the counter area neighboring area CNA through the downstream intermediate section CDIA toward the most downstream area CMDA.

  According to such a configuration, the strength of the electric field on the toner transport surface TTS and the counter wiring substrate surface CS gradually changes in the toner transport direction TTD. As a result, as in the fourth to sixth embodiments described above, the acceleration and deceleration of the toner T can be performed more smoothly.

<Eighth Embodiment of Toner Supply Apparatus>
The configuration of the eighth embodiment of the present invention will be described below using FIG.

  FIG. 19 is an enlarged side sectional view of the transport wiring substrate 63 and the counter wiring substrate 65 in the eighth embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 19, in this embodiment, instead of the transport electrode overcoating layer 63 d in FIG. 18, the transport electrode coating layer 63 c is configured such that the thickness gradually changes in the toner transport direction TTD. Yes.

  That is, the transport electrode coating layer 63c is configured to become thicker from the most upstream area TMUA through the upstream intermediate section TUIA toward the counter area CA. Further, the transport electrode coating layer 63c is configured to become thinner from the counter area CA toward the most downstream area TMDA through the downstream intermediate area TDIA.

  Further, in the present embodiment, instead of the counter electrode overcoating layer 65d in FIG. 18, the counter electrode coating layer 65c is configured such that the thickness gradually changes in the toner transport direction TTD.

  That is, the counter electrode coating layer 65c is configured to increase in thickness from the most upstream area CMUA to the counter area neighboring area CNA through the upstream intermediate area CUIA. The counter electrode coating layer 65c is configured to become thinner from the counter area neighboring area CNA through the downstream intermediate section CDIA toward the most downstream area CMDA.

  According to such a configuration, the strength of the electric field on the toner transport surface TTS and the counter wiring substrate surface CS gradually changes in the toner transport direction TTD. As a result, as in the fourth to seventh embodiments, the toner T can be accelerated and decelerated more smoothly.

<Ninth Embodiment of Toner Supply Device>
The configuration of the ninth embodiment of the present invention will be described below with reference to FIG.

  FIG. 20 is an enlarged side sectional view of the vicinity of the developing position DP in the ninth embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 20, in this embodiment, the transport electrode overcoating layer 63d (see FIG. 19) in the configuration of the above-described eighth embodiment is omitted. That is, in this embodiment, the transport electrode coating member 63c of the present invention is configured by the transport electrode coating layer 63c.

  In the present embodiment, the counter electrode overcoating layer 65d (see FIG. 19) in the configuration of the above-described eighth embodiment is omitted. That is, in this embodiment, the counter electrode coating member of the present invention is configured by the counter electrode coating layer 65c.

  Even with this configuration, the same operations and effects as those of the above-described eighth embodiment can be obtained.

<Tenth Embodiment of Toner Supply Device>
The configuration of the tenth embodiment of the present invention will be described below with reference to FIG.

  FIG. 21 is an enlarged side sectional view of the transport wiring board 63 and the counter wiring board 65 in the tenth embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 21, in this embodiment, the transport electrode coating layer 63c is formed so that the upstream side and the downstream side in the toner transport direction TTD are thinner than the counter area CA. That is, the transport electrode coating layer 63c is configured to become thicker from the most upstream area TMUA through the upstream intermediate section TUIA toward the counter area CA. Further, the transport electrode coating layer 63c is configured to become thinner from the counter area CA toward the most downstream area TMDA through the downstream intermediate area TDIA.

  Further, the transport electrode overcoating layer 63d is formed so that the upstream side and the downstream side in the toner transport direction TTD are thicker than the counter area CA. That is, the transport electrode overcoating layer 63d is configured to become thinner from the most upstream area TMUA through the upstream intermediate section TUIA toward the counter area CA. Further, the transport electrode overcoating layer 63d is configured to become thicker from the counter area CA toward the most downstream area TMDA through the downstream intermediate area TDIA.

  And the laminated body of the conveyance electrode coating layer 63c and the conveyance electrode overcoating layer 63d is formed in flat form so that it may become substantially constant thickness. Further, the transport electrode overcoating layer 63d is made of a material having a relative dielectric constant lower than that of the transport electrode coating layer 63c.

  In the present embodiment, the counter electrode coating layer 65c is formed such that the upstream side and the downstream side in the toner transport direction TTD are thinner than the counter area neighboring area CNA. That is, the counter electrode coating layer 65c is configured to become thicker from the most upstream area CMUA to the counter area CA through the upstream intermediate section CUIA. Further, the counter electrode coating layer 65c is configured to become thinner from the counter area CA toward the most downstream area CMDA via the downstream intermediate section CDIA.

  Further, the counter electrode overcoating layer 65d is formed so that the upstream side and the downstream side in the toner transport direction TTD are thicker than the counter area neighboring area CNA. That is, the counter electrode overcoating layer 65d is configured to become thinner from the most upstream area CMUA through the upstream intermediate section CUIA toward the counter area CA. Further, the counter electrode overcoating layer 65d is configured to become thicker from the counter area CA through the downstream intermediate part CDIA to the most downstream part CMDA.

  The laminated body of the counter electrode coating layer 65c and the counter electrode overcoating layer 65d is formed in a flat plate shape so as to have a substantially constant thickness. Furthermore, the counter electrode overcoating layer 65d is made of a material having a relative dielectric constant lower than that of the counter electrode coating layer 65c.

  In the toner electric field transport body 62 (transport wiring board 63) of the present embodiment having such a configuration, the (synthetic) relative dielectric constant of the laminate of the transport electrode overcoating layer 63d and the transport electrode coating layer 63c is opposite. The upstream side and the downstream side in the toner transport direction TTD are lower than the area CA. Thus, when a traveling wave voltage is applied to the transport electrode 63a, the electric field strength is higher on the upstream side and the downstream side in the toner transport direction TTD than on the counter area CA.

  Further, in the counter wiring substrate 65 of this embodiment having such a configuration, the (synthetic) relative dielectric constant of the laminate of the counter electrode overcoating layer 65d and the counter electrode coating layer 65c is greater than that of the counter area neighboring area CNA. However, the upstream side and the downstream side in the toner transport direction TTD are lower. Thus, when a traveling wave voltage is applied to the counter electrode 65a, the electric field strength is higher on the upstream side and the downstream side in the toner transport direction TTD than on the counter area neighboring area CNA.

  According to this configuration, the same operations and effects as those of the above-described embodiments can be obtained.

<Eleventh Embodiment of Toner Supply Device>
The configuration of the eleventh embodiment of the present invention will be described below with reference to FIG.

  FIG. 22 is an enlarged side sectional view of the transport wiring board 63 and the counter wiring board 65 in the eleventh embodiment of the toner supply device 6 shown in FIG.

  Referring to FIG. 22, in the present embodiment, the transport electrode 63a is configured such that the thickness gradually changes in the toner transport direction TTD.

  That is, the transport electrode 63a is configured to become thinner from the most upstream area TMUA through the upstream intermediate section TUIA toward the counter area CA. Further, the transport electrode 63a is configured to become thicker from the counter area CA through the downstream intermediate part TDIA toward the most downstream part TMDA.

  In the present embodiment, the counter electrode 65a is configured such that the thickness gradually changes as it goes in the toner transport direction TTD.

  That is, the counter electrode 65a is configured to become thinner from the most upstream area CMUA to the counter area neighboring area CNA through the upstream intermediate area CUIA. The counter electrode 65a is configured to increase in thickness from the counter area neighboring area CNA to the downstream intermediate area CDIA toward the most downstream area CMDA.

  According to such a configuration, as in the configuration of the fourth embodiment described above, the intensity of the electric field on the toner transport surface TTS and the counter wiring substrate surface CS gradually changes in the toner transport direction TTD. As a result, as in the fourth to tenth embodiments, the toner T can be accelerated and decelerated more smoothly.

<List of examples of modification>
In addition, each above-mentioned embodiment is only what illustrated the typical embodiment of this invention which the applicant considered the best at the time of the application of this application for the time being as mentioned above. Therefore, the present invention is not limited to the above-described embodiments. Accordingly, it goes without saying that various modifications can be made to the above-described embodiments within a range that does not change the essential part of the present invention.

  Hereinafter, some typical modifications will be exemplified. In the following description of the modified examples, the same reference numerals as those in the above embodiment can be used for members having the same configuration and function as those described in the above embodiments. And about description of this member, the description in the above-mentioned embodiment shall be used in the range which is not technically consistent.

  However, it goes without saying that 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 in terms of action and function in each component constituting the means for solving the problems of the present invention) is based on the description of the above embodiment and the following modifications. It should not be interpreted in a limited way. Such a limited interpretation, while improperly harming the applicant's interests (rushing to file under an earlier application principle), improperly imitates the patent for the protection and use of the invention Contrary to the purpose of the law, it is not allowed.

  (1) The application target of the present invention is not limited to a monochromatic laser printer. For example, the present invention can be suitably applied to a so-called electrophotographic image forming apparatus such as a color laser printer or a monochromatic and color copying machine. At this time, the shape of the photosensitive member may not be a drum shape as in the above-described embodiment. For example, a flat plate shape or an endless belt shape may be used.

  Alternatively, the present invention is also suitably applied to an image forming apparatus of a system other than the above-described electrophotographic system (for example, a toner jet system that does not use a photoreceptor, an ion flow system, a multi-stylus electrode system, etc.). obtain.

  (2) In the above-described embodiment, the waveform of the voltage generated by each of the power supply circuits VA to VD is a rectangular waveform, but may be a waveform of another shape such as a sine waveform or a triangular waveform. .

  In the above embodiment, the four power supply circuits VA to VD are provided and the phases of the voltages generated by the power supply circuits VA to VD are different from each other by 90 °. The phase of the voltage generated by the power supply circuit may be different by 120 °.

  (3) The transport wiring board 63 and the counter wiring board 65 in each of the above-described embodiments can be used independently.

  These can naturally be combined arbitrarily.

  For example, instead of the transport electrode coating layer 63c of the transport wiring board 63 in FIG. 3, the transport electrode coating layer 63c (a high relative dielectric constant portion 63c1, an upstream low relative dielectric constant portion 63c2, and a downstream low relative dielectric constant) in FIG. The one provided with the rate part 63c3) can be applied.

  Alternatively, the transport wiring board 63 in FIG. 3 and the counter wiring board 65 in FIG. 14 can be combined.

  Since it becomes redundant, it is not possible to exemplify all of them, but other combinations are naturally possible and are naturally included in the technical scope of the present invention.

  (4) In FIG. 3, the high relative dielectric constant portion 63d1 of the transport wiring substrate 63 may be provided so as to protrude from the upstream and / or downstream ends of the counter area CA in the toner transport direction TTD. That is, the high relative dielectric constant portion 63 d 1 in the transport wiring substrate 63 may be opposed to the high relative dielectric constant portion 65 d 1 in the counter wiring substrate 65.

  (5) In each of the embodiments described above, the change in relative dielectric constant and thickness may be continuous or stepwise.

  Further, in FIG. 14 and the like, the boundary positions of the upstream intermediate portion CUIA, the downstream intermediate portion CDIA, the upstream intermediate portion TUIA, and the downstream intermediate portion TDIA are limited to those described and illustrated in the above embodiments. Not.

  Furthermore, the upstream intermediate part CUIA, the downstream intermediate part CDIA, the upstream intermediate part TUIA, and the downstream intermediate part TDIA in FIG. 14 and the like can be further divided into a plurality of regions.

  (6) In FIGS. 18 and 19, the counter wiring substrate surface CS may be formed as a plane parallel to the xz plane.

  In FIGS. 18 and 19, the toner transport surface TTS (at least the portion facing the counter wiring substrate surface CS) in the central component 62a may be formed as a plane parallel to the xz plane.

  (7) In the tenth embodiment shown in FIG. 21, the relationship between the thickness and relative permittivity of the transport electrode coating layer 63c and the transport electrode overcoating layer 63d may be reversed.

  That is, the transport electrode coating layer 63c is formed so that the upstream side and the downstream side in the toner transport direction TTD are thicker than the counter area CA, and the upstream and downstream sides in the toner transport direction TTD from the counter area CA. The transport electrode overcoating layer 63d may be formed so as to be thin, and the transport electrode overcoating layer 63d may be made of a material having a relative dielectric constant higher than that of the transport electrode coating layer 63c.

  (8) The counter wiring substrate 65 may be omitted partially or entirely.

  (9) Other than these, various modifications other than these can be made without departing from the scope of the present invention.

  In addition, in each element constituting the means for solving the problems of the present invention, the elements expressed in terms of operation and function are the specific structures disclosed in the above-described embodiments and modifications, It includes any structure that can realize this action / function.

DESCRIPTION OF SYMBOLS 1 ... Laser printer 3 ... Photosensitive drum 6 ... Toner supply apparatus 31 ... Drum main body 32 ... Photosensitive layer 61 ... Toner box 61a ... Top plate 61a1 ... Toner passage hole 61b ... Bottom plate 61c ... Side plate 61d ... Toner stirring part 62 ... Toner electric field conveyance Body 62a ... Central component 62b ... Upstream component 62c ... Downstream component 63 ... Transport wiring board 63a ... Transport electrode 63b ... Transport electrode support film (transport electrode support member)
63c ... Transport electrode coating layer (transport electrode coating intermediate layer / transport electrode coating member)
63c1... High relative dielectric constant portion 63c2... Upstream low relative dielectric constant portion 63c3... Downstream low relative dielectric constant portion 63c4... Upstream intermediate relative dielectric constant portion 63c5. (Transport electrode covering member)
63d1... High relative permittivity portion 63d2... Upstream side low relative permittivity portion 63d3... Downstream side low relative permittivity portion 63d4... Upstream intermediate relative permittivity portion 63d5. ... counter wiring board 65a ... counter electrode 65b ... counter electrode support film (counter electrode support member)
65c ... Counter electrode coating layer (counter electrode covering intermediate layer / counter electrode covering member)
65c1 ... High relative dielectric constant portion 65c2 ... Upstream low relative dielectric constant portion 65c3 ... Downstream low relative dielectric constant portion 65c4 ... Upstream intermediate relative dielectric constant portion 65c5 ... Downstream intermediate relative dielectric constant portion 65d ... Counter electrode overcoating layer (Counter electrode covering member)
65d1 ... High relative dielectric constant portion 65d2 ... Upstream low relative dielectric constant portion 65d3 ... Downstream low relative dielectric constant portion 65d4 ... Upstream intermediate relative dielectric constant portion 65d5 ... Downstream intermediate relative dielectric constant portion CA ... Opposite area CDA ... Downstream Part CDIA ... downstream side intermediate part CMDA ... most downstream part CMUA ... most upstream part CNA ... counter area proximity part CS ... counter wiring substrate surface CUA ... upstream part CUIA ... upstream side intermediate part DP ... development position LI ... electrostatic latent image LS ... latent image forming surface T ... toner TDA ... downstream part TDIA ... downstream intermediate part TMDA ... most downstream part TMUA ... most upstream part TTD ... toner conveyance direction TTS ... toner conveyance surface TUA ... upstream part TUIA ... upstream intermediate part

Claims (3)

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:
A plurality of transport electrodes arranged along the sub-scanning direction and configured to transport the developer in a predetermined developer transport direction by applying a traveling-wave voltage; and
A transport electrode support member configured to support the transport electrode on a surface thereof;
A transport electrode covering member that is formed so as to cover the surface of the transport electrode support member and the transport electrode, and includes a developer transport surface that is parallel to the main scanning direction and faces the latent image forming surface;
A transport electrode covering intermediate layer formed between the transport electrode covering member and the transport electrode;
With
A laminate of the transport electrode covering intermediate layer and the transport electrode covering member is formed into a flat plate having a substantially constant thickness,
The transport electrode coating intermediate layer and the transport electrode coating member are configured such that the transport electrode coating member has a lower dielectric constant than the transport electrode coating intermediate layer ,
The transport electrode covering intermediate layer is formed so that the upstream side and the downstream side in the developer transport direction are thinner than the facing region where the latent image forming surface and the developer transport surface face each other. An image forming apparatus. The image forming apparatus according to claim 1,
The transport electrode coating intermediate layer is
An image forming apparatus comprising an upstream intermediate portion having a thickness intermediate between the most upstream portion and the facing region between the most upstream portion in the developer conveying direction and the facing region. apparatus. The image forming apparatus according to claim 1, wherein:
The transport electrode coating intermediate layer is
An image forming apparatus comprising a downstream intermediate portion having a thickness intermediate between the most downstream portion and the facing region between the most downstream portion in the developer transport direction and the facing region. apparatus.