JP4449952B2 - Developer supply apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a developer electric field transport device, a developer supply device, and an image forming apparatus.

  Many mechanisms for conveying toner (developer) using a traveling wave electric field in an image forming apparatus have been conventionally known (for example, Japanese Patent Laid-Open No. 63-13074, Japanese Patent Publication No. 5-31146, JP 2002-351218, JP 2003-15417, JP 2004-157259, JP 2005-275127, and the like. In such a mechanism, a large number of linear electrodes are arranged in a row on an insulating substrate.

According to the above-described configuration, a traveling wave electric field is formed by sequentially applying a multiphase AC voltage to the multiple linear electrodes. The charged toner is conveyed in a predetermined direction by the action of the traveling wave electric field.
JP 63-13074 A Japanese Patent Publication No. 5-31146 JP 2002-351218 A JP 2003-15417 A JP 2004-157259 A JP 2005-275127 A

  In the mechanism capable of transporting the charged developer by the traveling wave electric field as described above (hereinafter referred to as “developer electric field transport device”), there is an area on the substrate where the developer is not transported smoothly. When it occurs, the developer can stay in the area for a long time. Due to the retention of the developer, the developer is likely to be fixed or scattered to the outside.

  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 that can smoothly transport a developer in a predetermined direction by a traveling wave, a developer supply device including the developer electric field transport device, and an image forming apparatus. It is in.

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

  The electrostatic latent image carrier has a latent image forming surface. The latent image forming surface is formed in parallel with a predetermined main scanning direction, and is configured so 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.

  In the present invention, the developer supply device includes a developer transport body and a charge removal member.

  The developer transport body has a developer transport surface parallel to the main scanning direction. The developer transport body is disposed so that the developer transport surface faces the electrostatic latent image carrier.

  The plurality of transport electrodes are arranged along the sub-scanning direction. These transport electrodes are provided along the developer transport surface. These transport electrodes are configured and arranged so as to be able to transport the developer in a predetermined developer transport direction when a traveling wave voltage is applied.

  The discharging member is located on the upstream side and / or the downstream side in the developer transport direction from the closest position where the distance between the latent image forming surface and the developer transport surface is the shortest. It arrange | positions so that a conveyance surface may be opposed. The charge eliminating member is configured to suppress charge-up on the developer transport surface by air discharge.

  The static elimination member can be provided, for example, so as to face a facing region that is a region facing the electrostatic latent image carrier on the developer transport surface. Further, a first static elimination member may be provided on the upstream side in the developer conveyance direction from the closest position, and a second static elimination member may be provided on the downstream side in the developer conveyance direction from the closest position.

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

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

  A predetermined traveling-wave voltage is applied to the plurality of transport electrodes provided along the developer transport surface in the developer transport body provided in the developer supply apparatus. As a result, the charged developer moves on the developer transport surface along the developer transport direction.

  Here, the latent image forming surface and the developer transport surface are surfaces parallel to the main scanning direction. Therefore, in the vicinity of the closest position where the distance between the latent image forming surface and the developer transport surface is the shortest, the latent image forming surface and the developer transport surface face each other in a parallel state. Can do. Then, in the vicinity of this closest position, the electrostatic latent image is developed by the charged developer that has been transported on the developer transport body.

  By the way, when the developer is transported on the developer transport surface, the developer transport surface and the developer are rubbed. Due to this friction, the developer transport surface may be charged. As the developer is transported on the developer transport surface, the triboelectric charge amount on the developer transport surface can increase. That is, the developer transport surface can be charged up. When such charge-up occurs, the developer may not be smoothly transported on the developer transport surface.

  Therefore, in the image forming apparatus of the present invention, the charge removal of the developer transport surface on the upstream side and / or the downstream side in the developer transport direction from the closest position is suppressed by the charge eliminating member. For example, when the development of the electrostatic latent image is not performed (specifically, after the completion of development of the electrostatic latent image), charge-up suppression of the developer transport surface (hereinafter referred to as “the development”). This is referred to as “static elimination on the agent transport surface”).

  According to such a configuration, the transport of the developer toward the vicinity of the closest position and the transport of the developer from the vicinity of the closest position to the downstream side in the developer transport direction are smoothly performed. Can be broken.

  The image forming apparatus includes: a feeding power supply unit that feeds power to the transport electrode; a neutralization power feeding unit that feeds power to the static elimination member; a control unit that controls operations of the feeding power supply unit and the neutralization power feeding unit; May be further provided. Here, when supplying power to the static elimination member, the control unit is configured to stop the feeding of the transport electrode positioned upstream in the developer transport direction relative to the static elimination member, It is comprised so that the said electric power feeding part for static elimination may be controlled.

  At this time, when the control unit supplies power to the charge removal member, at least the transfer power supply unit and the charge removal unit are configured to supply power to the transfer electrode positioned at the downstream side in the developer transfer direction from the charge removal member. You may be comprised so that the electric power feeding part may be controlled.

  In the image forming apparatus having such a configuration, the traveling-wave voltage as described above is applied to the transport electrode by the transport power feeding unit. Further, the electricity removing member supplies electricity to the electricity removing member to remove electricity from the developer transport surface. The control unit controls operations of the conveyance power supply unit and the charge removal power supply unit. In addition, when supplying power to the charge removal member, the control unit stops the power supply of the transfer electrode located on the upstream side in the developer transfer direction with respect to the charge removal member, Controls the electricity removal power supply unit.

  In this case, the traveling-wave voltage described above can be fed to at least the transport electrode positioned downstream in the developer transport direction from the charge removal member. For example, the traveling wave voltage described above can be supplied to the static elimination region and the transport electrode corresponding to the downstream side in the developer transport direction from the static elimination region. Here, the neutralization region is a region in the vicinity of the position closest to the neutralization member on the developer transport surface, and is a region that is neutralized by the neutralization member.

  As described above, the first static elimination member is located upstream in the developer conveyance direction from the closest position, and the second static elimination member is located downstream in the developer conveyance direction from the closest position. The provided configuration can be adopted. In such a configuration, when the control unit supplies power to the charge removal member, the control unit stops power supply to the transport electrode located upstream from the first charge removal member on the most upstream side in the developer transport direction. In this manner, the feeding power supply unit and the neutralization power feeding unit are controlled.

  In this case, the traveling-wave voltage described above can be fed to at least the transport electrode positioned downstream in the developer transport direction from the first charge removal member. That is, the traveling-wave voltage described above can be supplied to the charge removal region by the first charge removal member and the transport electrode corresponding to the downstream side in the developer transport direction from the charge removal region.

  According to such a configuration, it is possible to prevent the developer from being conveyed one after another to the charge removal region during the charge removal on the developer conveyance surface. Thereby, the charge removal of the developer conveyance surface can be performed efficiently. In addition, the developer placed on the charge removal area can be appropriately discharged. Therefore, the developer that adheres electrostatically and firmly on the developer transport surface can be smoothly removed from the developer transport surface without applying a mechanical load such as friction.

  The image forming apparatus may further include a grid electrode interposed between the developer transport surface and the charge removal member. That is, a scorotron type static eliminator can be formed by the static eliminator and the grid electrode. According to this configuration, the charge removal on the developer transport surface can be performed more stably.

  The image forming apparatus may further include a grid power supply unit that supplies power to the grid electrode. In this case, when supplying power to the transport electrode while stopping the power supply to the charge removal member, the control unit is configured to set the potential of the grid electrode to the same polarity as the charging polarity of the developer. The power feeding unit is configured to be controlled.

  In this configuration, for example, at the time of developing the electrostatic latent image, the grid electrode is set to a potential having the same polarity as the charging polarity of the developer. Thereby, inadvertent floating of the developer from the developer transport surface can be suppressed. In addition, adhesion of the developer to the grid electrode can be suppressed.

(2) The developer supply device of the present invention is configured to be able to supply the developer image carrier along a predetermined developer transport direction in a state where the developer is charged.

  The developer carrying member has a developer image carrying surface. The developer image carrying surface is a surface on which an image by the developer can be carried, and is a surface parallel to a predetermined main scanning direction. The developer image carrying surface can move along a sub-scanning direction orthogonal to the main scanning direction.

  Specifically, as the developer image carrier, for example, an electrostatic latent image carrier having a latent image forming surface configured to form an electrostatic latent image by potential distribution can be used. Alternatively, as the developer image carrier, for example, a recording medium (paper) transported along the sub-scanning direction can be used. Alternatively, as the developer image carrier, for example, an intermediate transfer member configured and arranged so as to be able to transfer the developer onto the recording medium by facing the recording medium can be used.

  The developer supply device of the present invention includes a developer transport body and a charge removal member.

  The developer transport body has a developer transport surface parallel to the main scanning direction. The developer transport body is disposed so that the developer transport surface faces the developer image carrier.

  The plurality of transport electrodes are arranged along the sub-scanning direction. These transport electrodes are provided along the developer transport surface. These transport electrodes are configured and arranged so as to be able to transport the developer in a predetermined developer transport direction when a traveling wave voltage is applied.

  The charge eliminating member is located on the upstream side and / or the downstream side in the developer transport direction from the closest position where the distance between the developer image carrying surface and the developer transport surface is the shortest. It arrange | positions so that an agent conveyance surface may be opposed. The charge eliminating member is configured to suppress charge-up on the developer transport surface by air discharge.

  The charge eliminating member can be provided, for example, so as to face a facing region that is a region facing the developer image carrier on the developer transport surface. Further, a first static elimination member may be provided on the upstream side in the developer conveyance direction from the closest position, and a second static elimination member may be provided on the downstream side in the developer conveyance direction from the closest position.

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

  A predetermined traveling wave voltage is applied to the plurality of transport electrodes provided along the developer transport surface. As a result, the charged developer moves on the developer transport surface along the developer transport direction.

  Here, the developer image carrying surface and the developer transport surface are parallel to the main scanning direction. Therefore, the developer image carrying surface and the developer carrying surface are parallel to each other in the vicinity of the closest position where the distance between the developer image carrying surface and the developer carrying surface is the shortest. You can face each other. Then, in the vicinity of the closest position, an image of the charged developer conveyed on the developer conveyance body is formed and carried on the developer image carrying surface.

  In the developer supply apparatus of the present invention, the charge removal member performs charge removal on the developer transport surface upstream and / or downstream in the developer transport direction from the closest position. For example, when the image is not formed with the developer on the developer image carrying surface (specifically, after the above-described image formation is completed), the charge on the developer transport surface is removed. Done.

  According to this configuration, the developer can be smoothly transported on the developer transport surface.

  The developer supply device includes a conveyance power supply unit that supplies power to the conveyance electrode, a neutralization power supply unit that supplies power to the neutralization member, and a control unit that controls operations of the conveyance power supply unit and the neutralization power supply unit. , May be further provided. Here, when supplying power to the static elimination member, the control unit is configured to stop the feeding of the transport electrode positioned upstream in the developer transport direction relative to the static elimination member, It is comprised so that the said electric power feeding part for static elimination may be controlled.

  At this time, when the control unit supplies power to the charge removal member, at least the transfer power supply unit and the charge removal unit are configured to supply power to the transfer electrode positioned at the downstream side in the developer transfer direction from the charge removal member. You may be comprised so that the electric power feeding part may be controlled.

  In the developer supply apparatus having such a configuration, the traveling-wave voltage as described above is applied to the transport electrode by the transport power supply unit. Further, the electricity removing member supplies electricity to the electricity removing member to remove electricity from the developer transport surface. The control unit controls operations of the conveyance power supply unit and the charge removal power supply unit. In addition, when supplying power to the charge removal member, the control unit stops the power supply of the transfer electrode located on the upstream side in the developer transfer direction with respect to the charge removal member, Controls the electricity removal power supply unit.

  In this case, the traveling-wave voltage described above can be fed to at least the transport electrode positioned downstream in the developer transport direction from the charge removal member. For example, the traveling wave voltage described above can be supplied to the static elimination region and the transport electrode corresponding to the downstream side in the developer transport direction from the static elimination region.

  As described above, a configuration in which the first static elimination member and the second static elimination member are provided can be employed. In such a configuration, when the control unit supplies power to the charge removal member, the control unit stops power supply to the transport electrode located upstream from the first charge removal member on the most upstream side in the developer transport direction. In this manner, the feeding power supply unit and the neutralization power feeding unit are controlled.

  In this case, the traveling-wave voltage described above can be fed to at least the transport electrode located downstream of the first charge removal member in the developer transport direction. That is, the traveling-wave voltage described above can be supplied to the charge removal region by the first charge removal member and the transport electrode corresponding to the downstream side in the developer transport direction from the charge removal region.

  According to this configuration, the charge removal on the developer transport surface can be performed efficiently. Further, the developer that adheres electrostatically and firmly on the developer transport surface can be smoothly removed from the developer transport surface without applying a mechanical load such as friction.

  The developer supply device may further include a grid electrode interposed between the developer transport surface and the charge removal member. According to this configuration, the charge removal on the developer transport surface can be performed more stably.

  The developer supply apparatus may further include a grid power supply unit that supplies power to the grid electrode. In this case, when supplying power to the transport electrode while stopping the power supply to the charge removal member, the control unit is configured to set the potential of the grid electrode to the same polarity as the charging polarity of the developer. The power feeding unit is configured to be controlled.

  In such a configuration, for example, when forming an image with the developer on the developer image carrying surface, the grid electrode is set to a potential having the same polarity as the charging polarity of the developer. The Thereby, inadvertent floating of the developer from the developer transport surface can be suppressed. In addition, adhesion of the developer to the grid electrode can be suppressed.

(3) 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 on which a thin layer of developer can be carried and can be formed in parallel with a predetermined main scanning direction. The developer carrying surface can move along a predetermined moving direction. The moving direction may be set to be parallel to a sub-scanning direction orthogonal to the main scanning direction.

  Specifically, as the developer carrying member, for example, an electrostatic latent image carrying member having a latent image forming surface configured to be able to form an electrostatic latent image by potential distribution can be used. Alternatively, as the developer carrying member, for example, a recording medium (paper) conveyed along the sub-scanning direction can be used. Alternatively, as the developer carrier, for example, the developer can be transferred onto the recording medium or the electrostatic latent image carrier by facing the recording medium or the electrostatic latent image carrier. A roller, sleeve, or belt-shaped member (developing roller, developing sleeve, etc.) constructed and arranged can be used.

  The developer electric field transport device of the present invention includes a developer transport body and a charge removal member.

  The developer transport body has a developer transport surface parallel to the main scanning direction. The developer transport body is disposed so that the developer transport surface faces the developer carrier.

  A plurality of the transport electrodes are arranged along the moving direction. These transport electrodes are provided along the developer transport surface. These transport electrodes are configured and arranged so as to be able to transport the developer in a predetermined developer transport direction when a traveling wave voltage is applied.

  The discharging member is located on the upstream side and / or the downstream side in the developer transport direction from the closest position where the distance between the developer carrying surface and the developer transport surface is the shortest. It arrange | positions so that a conveyance surface may be opposed. The charge eliminating member is configured to suppress charge-up on the developer transport surface by air discharge.

  The static elimination member can be provided, for example, so as to face a facing region that is a region facing the developer carrier on the developer transport surface. Further, a first static elimination member may be provided on the upstream side in the developer conveyance direction from the closest position, and a second static elimination member may be provided on the downstream side in the developer conveyance direction from the closest position.

  The developer electric field transport apparatus of the present invention having such a configuration operates as follows.

  A predetermined traveling wave voltage is applied to the plurality of transport electrodes. As a result, the charged developer moves on the developer transport surface along the developer transport direction. Here, the charge removal member suppresses charge-up of the developer transport surface on the upstream side and / or downstream side in the developer transport direction from the closest position. For example, when the image is not formed by the developer on the developer carrying surface (specifically, after the above-described image formation is completed), the developer transport surface is neutralized. Is called.

  According to this configuration, the developer can be smoothly transported on the developer transport surface.

  The developer electric field transport device may further include a grid electrode interposed between the developer transport surface and the charge removal member. Thereby, the charge removal of the developer conveying surface can be performed more stably.

  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 according to the present embodiment.

  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, a toner supply device 6, and a control unit 7.

  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.

  On the peripheral surface of the photosensitive drum 3 as the electrostatic latent image carrier, developer image carrier, and developer carrier of the present invention, the latent image forming surface, developer image bearing surface, and developer of the present invention are provided. A latent image forming surface LS is formed as an agent carrying surface. The latent image forming surface is formed as a cylindrical surface parallel to the main scanning direction (z 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 rotationally driven in a direction indicated by an arrow in the figure with the central axis C as a center so that the latent image forming surface LS can move along the sub-scanning direction orthogonal to the main scanning direction. It is configured to be able to.

  The “sub-scanning direction” is an arbitrary direction orthogonal to the main scanning direction. Usually, the sub-scanning direction is a direction intersecting the vertical line. That is, the sub-scanning direction is 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 drawing).

  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 to uniformly negatively charge the latent image forming surface LS.

  The scanner unit 5 is configured to generate a laser beam LB modulated based on image data. Further, the scanner unit 5 places the generated laser beam LB at a position on the latent image forming surface LS and downstream of the charger 4 in the rotation direction of the photosensitive drum 3 (counterclockwise in FIG. 1). The image is formed (exposed) at the position of. Further, the scanner unit 5 is configured to move (scan) 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.

  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 negatively charged toner, which is a fine particle dry developer (powder developer), to the latent image forming surface LS in a charged state. The detailed configuration of the toner supply device 6 will be described later.

  The control unit 7 includes a CPU, a RAM, a ROM, and the like, and is configured to be able to control driving and voltage output of each unit provided in the laser printer 1.

<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 that is the peripheral surface of the photosensitive drum 3 with the paper P interposed therebetween. The transfer roller 22 is configured to be rotationally driven in a direction (clockwise) indicated by an arrow in the drawing. The transfer roller 22 is applied such that 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. Are connected to a bias power supply circuit (not shown).

<< 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 a negatively chargeable photoconductive layer that exhibits electron conductivity when exposed to laser light having a predetermined wavelength, and is composed of a synthetic resin layer such as polycarbonate doped with a phthalocyanine dye or the like. . The latent image forming surface LS is configured by the outer peripheral surface of the photosensitive layer 32.

<< Toner Supply Device >>
A toner box 61 that forms a casing of the toner supply device 6 includes a top plate 61a, a bottom plate 61b, and a side plate 61c. The toner box 61 is filled with black toner T, which is a negatively chargeable, non-magnetic single component, mainly composed of polyester.

  The top plate 61a is a rectangular plate-like member in plan view, and is arranged in parallel with the horizontal plane. The bottom plate 61b is a rectangular plate-like member in plan view, and is disposed below the top plate 61a. The bottom plate 61b is arranged to be inclined so as to rise in the y-axis positive direction as it goes in the x-axis positive direction in the figure. The four sides of the outer edge of the top plate 61a and the bottom plate 61b are connected to four side plates 61c (only two of these side plates 61c are shown in FIG. 2), so that the toner box 61 has toner. It is comprised so that it can accommodate so that T may not leak outside.

  A toner passage hole 61d is formed in the top plate 61a. The toner passage hole 61d is formed at a position where the top plate 61a and the photosensitive layer 32 are close to each other. The toner passage hole 61d 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 passing hole 61d 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.

<<< Toner carrier >>>
Inside the toner box 61 is accommodated a toner transport body 62 as a developer transport body of the present invention. The toner transport body 62 is a plate-like member having a predetermined thickness. The toner 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 61d 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 61d.

  The upstream side component 62b extends further to the upstream side and obliquely downward from the upstream end of the central component 62a in the toner conveyance direction (x-axis positive direction in the drawing). 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. Further, even when the amount of toner T becomes small because the upstream end of the upstream component 62b in the toner transport direction 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 part) 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 conveyance direction and obliquely downward. That is, the upstream side configuration part 62b is provided as a plate-like member that is arranged so as to descend obliquely downward as it moves away from the central configuration part 62a. Further, the downstream end of the downstream component 62c in the toner transport direction is in the vicinity of the bottom plate 61b of the toner box 61 and in the vicinity of the most downstream side plate 61c in the toner transport direction (that is, the toner box). The downstream side component 62c is provided so that the toner T can smoothly return to the bottom plate 61b by reaching the vicinity of the shallowest portion 61).

  The toner transport body 62 has a toner transport surface TS parallel to the main scanning direction. The toner transport body 62 is disposed so that the toner transport surface TS faces the latent image forming surface LS on the photosensitive drum 3.

  A plurality of transport electrodes 62d are formed along the toner transport surface TS (so as to be positioned near the toner transport surface TS). Each transport electrode 62d is a linear wiring pattern made of a metal thin film, and is provided in parallel to each other so as to have a longitudinal direction in the main scanning direction. These transport electrodes 62d are arranged at equal intervals along the sub-scanning direction.

  FIG. 3 is an enlarged side sectional view of a portion where the toner conveying body 62 and the photosensitive drum 3 shown in FIG. 2 face each other.

  Referring to FIG. 3, the laser printer 1 includes four power feeding units VA to VD that are power supply circuits for feeding power to the transport electrode 62d. A large number of the respective transport electrodes 62d arranged along the sub-scanning direction (the x-axis direction in the figure) are connected to the same transport power feeding section every third.

  That is, the transport electrode EA connected to the transport power supply unit VA, the transport electrode EB connected to the transport power supply unit VB, the transport electrode EC connected to the transport power supply unit VC, and the transport power supply unit VD A transport electrode ED, a transport electrode EA connected to the transport power supply unit VA, a transport electrode EB connected to the transport power supply unit VB, are arranged in order along the sub-scanning direction. In FIG. 3, the transport electrode 62d connected to the power feeding unit VA for transport is indicated as a transport electrode EA. The same applies to the transport electrode EB or the transport electrode ED.

  FIG. 4 is a graph showing a waveform of a voltage generated by the conveyance power supply units VA to VD shown in FIG. As shown in FIG. 4, each of the power feeding units VA to VD for conveyance is configured to generate an AC voltage having substantially the same waveform. Here, the waveforms of the voltages generated by the power feeding units VA to VD for conveyance are different in phase by 90 °.

  That is, referring to FIG. 3 and FIG. 4, each of the power feeding units VA to VD for transportation is shown in FIG. 3 so that the phase of the voltage is delayed by 90 ° from the power feeding unit VA to the power feeding unit VD. It is controlled by the control unit 7 shown.

  In this way, each of the transport electrodes 62d is applied with a traveling-wave voltage by the transport power supply units VA to VD whose output operation is controlled by the control unit 7, so that the toner T is applied on the toner transport surface TS. The traveling wave electric field that can be conveyed in the toner conveying direction can be formed and arranged.

  Referring to FIG. 3, the transport electrode 62d is formed on a support plate 62e, which is a plate member made of synthetic resin. The surface of the support plate 62e on which the transport electrode 62d is formed is covered with a nylon coating film 62f that is a synthetic resin. The surface of the synthetic resin coating film 62f constitutes the toner transport surface TS.

  Referring to FIG. 2, an agitator 63 that is a stirrer is provided at the deepest portion of the toner box 61 and below the lower end portion of the upstream side configuration portion 62 b of the toner transport body 62. The agitator 63 stirs and flows the toner T at the deepest part of the toner box 61 and friction between the toner T and the toner transport surface TS, so that the toner T can be negatively charged. It is configured to be rotatable in the direction indicated by the arrow (clockwise).

  A first static elimination member 64 and a second static elimination member 65 are provided so as to face the toner conveyance surface TS in the central configuration portion 62 a of the toner conveyance body 62. The first charge removal member 64 and the second charge removal member 65 are configured to suppress charge-up on the toner transport surface TS, which is a synthetic resin surface, by air discharge.

  The first charge removal member 64 is connected to the end of the central component 62a on the upstream side in the toner transport direction from the closest position P0 where the distance between the latent image forming surface LS and the toner transport surface TS is the shortest. It arrange | positions so that it may oppose. The second static elimination member 65 is connected to the end of the central component 62a on the downstream side in the toner transport direction from the closest position P0 where the distance between the latent image forming surface LS and the toner transport surface TS is the shortest. It arrange | positions so that it may oppose.

  The first charge removal member 64 is electrically connected to the first charge removal portion VE. The second static elimination member 65 is electrically connected to the second static elimination power supply unit VF. The first static elimination power supply unit VE and the second static elimination power supply unit VF are configured to supply power to the first static elimination member 64 and the second static elimination member 65, respectively, under the control of the control unit 7. The first static elimination power supply unit VE and the second static elimination power supply unit VF are configured to output an AC voltage having 0 V as a reference voltage.

  FIG. 5 is a front view of the first static elimination member 64 shown in FIG. 2 (the second static elimination member 65 is similarly configured). Referring to FIG. 5, the first static elimination member 64 is composed of a rod-shaped metal member having a longitudinal direction in the main scanning direction. A plurality of sharp protrusions 64 a are formed at the lower end portion of the first static elimination member 64. That is, the 1st static elimination member 64 is comprised from the comb-shaped electrode member.

<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. In addition, although description is abbreviate | omitted in the following operation | movement description, each part (The paper conveyance mechanism 2, the photosensitive drum 3, the charger 4, the scanner unit 5, the toner supply apparatus 6, and various types with which the laser printer 1 was equipped. The operation of the power supply unit) is all controlled by the control unit 7.

<< 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 a transfer position where the photosensitive drum 3 and the transfer roller 22 face each other.

<< Carrying of toner image on latent image forming surface >>
As described above, while the sheet P is being conveyed toward the transfer position, 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 negatively by the charger 4.

  The latent image forming surface LS charged by the charger 4 is a position facing (facing) the scanner unit 5 by the rotation of the photosensitive drum 3 in the direction indicated by the arrow (counterclockwise) in the drawing. It moves along the sub-scanning direction to the scanning position. At this scanning position, the laser beam LB modulated based on the image information is irradiated onto the latent image forming surface LS while being scanned along the main scanning direction. Depending on the modulation state of the laser beam LB, a portion where the negative charges on the latent image forming surface LS disappear is generated. As a result, an electrostatic latent image is formed on the latent image forming surface LS by an image-like distribution of negative charges.

  The electrostatic latent image formed on the latent image forming surface LS moves toward a position facing the toner supply device 6 by the rotation of the photosensitive drum 3 in the direction indicated by the arrow (counterclockwise) in the drawing. To do.

<<< Conveyance and supply of charged toner >>>
Referring to FIG. 2, the agitator 63 rotates in a direction (clockwise) indicated by an arrow in the drawing. The rotation of the agitator 63 causes friction between the toner T and the toner transport surface TS (the surface of the synthetic resin coating film 62f in FIG. 3) in the upstream side component 62b. As a result, the toner T is charged negatively.

  Here, as described above, the upstream end (in the negative x-axis direction in the drawing) end of the toner transport body 62 (upstream configuration section 62b) in the toner transport direction is buried in the toner T. The toner T stored in the toner box 61 is always supplied onto the toner transport surface TS.

  Further, a voltage is applied in a traveling wave shape to the plurality of transport electrodes 62 d in the toner transport body 62. As a result, a predetermined traveling-wave electric field is formed on the toner transport surface TS. Due to this electric field, the negatively charged toner T goes up the inclined toner transport surface TS in the upstream side component 62b, reaches the central component 62a, and is transported to the closest position P0.

  FIG. 6 is an enlarged side sectional view showing the vicinity of the closest position P0 in the toner transport body 62 shown in FIG.

  Referring to FIGS. 4 and 6, at time t <b> 1 in FIG. 4, as shown in FIG. 6A, at a position between AB that is a position between the transport electrode EA and the transport electrode EB. The electric field EF1 is formed in the direction opposite to the toner conveyance direction (the negative direction of the x axis in FIG. 6). On the other hand, an electric field EF2 in the same direction as the toner transport direction (the x-axis positive direction in FIG. 6) is formed at the CD position, which is a position between the transport electrode EC and the transport electrode ED. Further, the position between BC, which is a position between the transport electrode EB and the transport electrode EC, and the position between DA, which is a position between the transport electrode ED and the transport electrode EA, are in the direction along the toner transport direction. An electric field is not formed.

  That is, at the time point t1, the negatively charged toner T receives an electrostatic force in the same direction as the toner conveyance direction at the position between AB. Further, at the position between BC and the position between DA, the negatively charged toner T receives almost no electrostatic force in the direction along the toner conveyance direction. Further, at the position between the CDs, the negatively charged toner T receives an electrostatic force opposite to the toner transport direction. Therefore, at time t1, the negatively charged toner T is collected at the position between BC.

  Similarly, at time t2, the negatively charged toner T is collected at the position between the CDs. Next, at time t3, the negatively charged toner T is collected at the position between the DAs. As described above, the region where the toner T is collected moves in the toner transport direction along the toner transport surface TS as time passes.

  In this way, a voltage as shown in FIG. 4 is applied to each transport electrode 62d (EA to ED), so that a traveling-wave electric field is formed on the toner transport surface TS. . As a result, the toner T is transported in the toner transport direction (x-axis positive direction in the figure) while hopping in the y direction in the figure.

<<< Development of electrostatic latent image >>>
Referring to FIG. 2, as described above, the negatively charged toner T moves up the sloped toner conveyance surface TS in the upstream side configuration portion 62b, reaches the central configuration portion 62a, and is conveyed to the closest position P0. Is done.

  In the vicinity of the closest position P0, the electrostatic latent image formed on the latent image forming surface LS is developed by the toner T. That is, the toner T adheres to a portion on the latent image forming surface LS where the negative charge in the electrostatic latent image 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.

  The remaining toner T that has not been used for the development of the electrostatic latent image is conveyed toward the downstream side configuration part 62c. Then, the toner T falls downward from the downstream side component 62 c and returns to the bottom of the toner box 61.

<< 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 indicated by the arrow (counterclockwise). ) To the transfer position. At this transfer position, the toner image is transferred onto the paper P from the latent image forming surface LS.

<< Static removal operation on toner transport surface >>
Next, the charge eliminating operation for suppressing the charge-up of the toner transport surface TS will be described with reference to FIG.

  As described above, the toner T made of synthetic resin is conveyed in the toner conveying direction on the toner conveying surface TS which is a surface made of synthetic resin. At this time, the toner transport surface TS can be charged up by friction between the toner T and the toner transport surface TS. When such charge-up occurs, the toner T is firmly fixed on the toner transport surface TS by electrostatic force, which may hinder smooth transport of the toner T on the toner transport surface TS.

  Therefore, at the time of non-development in which development of the electrostatic latent image is not performed, the first static elimination power supply unit VE and the second static elimination power supply unit VF are used for the first static elimination member 64 and the second static elimination member 65. An AC voltage with 0V as a reference voltage is applied. Thereby, the upstream side neutralization region A1 and the downstream side neutralization region A2 which are regions facing the first neutralization member 64 and the second neutralization member 65 on the toner transport surface TS are neutralized. At this time, the toner T on the upstream charge removal area A1 and the downstream charge removal area A2 can also be discharged appropriately.

  Here, the upstream charge removal area A1 is an area in the vicinity of the facing position CP1, which is a position where the first charge removing member 64 and the toner transport surface TS face each other in the closest state, and is located above the facing position CP1. The region may have a slight width toward the upstream side and the downstream side in the toner conveyance direction. Similarly, the downstream charge removal area A2 may also occur from a position upstream in the toner transport direction from the facing position CP2 to a position downstream in the toner transport direction from the facing position CP2.

  During this neutralization operation, power supply to the transport electrode 62d located upstream of the upstream neutralization area A1 in the toner transport direction is stopped. Then, the generation of the traveling-wave electric field stops on the toner transport surface TS on the upstream side in the toner transport direction from the upstream charge removal area A1. Thereby, the conveyance of the toner T toward the upstream side charge removal area A1 is stopped. Therefore, the charge removal in the upstream charge removal area A1 can be performed efficiently.

  On the other hand, power is supplied to the upstream charge removal area A1 and the transport electrode 62d located further downstream in the toner transport direction. As a result, the toner T that has been appropriately neutralized and relaxed in charge is transported toward the downstream side in the toner transport direction, and passes through the downstream side component 62c toward the bottom of the toner box 61 (bottom plate 61b). Reflux.

  Further, at the time of development where the electrostatic latent image is being developed, and in the development preparation stage, the first static elimination member 64 and the second static elimination member 64 and the second static elimination power feed unit VF are used. The potential of the charge removal member 65 is set to a negative potential having the same polarity as the toner T. Thereby, the adhesion of the toner T to the first static elimination member 64 and the second static elimination member 65 can be suppressed.

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

  Hereinafter, some 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 embodiment. And about description of this member, the description in the above-mentioned embodiment shall be used in the range which is not technically consistent.

  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) The outputs of the first static elimination power supply unit VE and the second static elimination power supply unit VF may not be an AC voltage, and the polarity is not limited.

(3) The arrangement and configuration of the static elimination members (the first static elimination member 64 and the second static elimination member 65) are not particularly limited. For example, the static elimination member may have a configuration equivalent to a corotron type or scorotron type charger.

  FIG. 7 is a side sectional view showing a modified example of the configuration around the first charge removal member 64 and the second charge removal member 65 in the toner supply device 6 shown in FIG.

  As shown in FIG. 7, the first grid electrode 66 may be provided so as to face the first charge removal member 64. The first grid electrode 66 is electrically connected to the grid power supply unit VG1. Further, the second grid electrode 67 may be provided so as to face the second static elimination member 65. The second grid electrode 67 is electrically connected to the grid power supply unit VG2.

  In such a configuration, the following operations can be performed during development and non-development.

  As indicated by (i) in the figure, during the development, the power supply to the first charge removal member 64 and the second charge removal member 65 from the first charge removal portion VE and the second charge removal portion VF is interrupted. Is done. At this time, the grid power supply unit VG1 and the grid power supply unit VG2 set the potentials of the first grid electrode 66 and the second grid electrode 67 to the same negative polarity as that of the toner T. Thereby, the adhesion of the toner T to the first static elimination member 64, the second static elimination member 65, the first grid electrode 66, and the second grid electrode 67 can be suppressed. Further, inadvertent floating of the toner T from the toner transport surface TS can be suppressed.

  As indicated by (ii) in the figure, during the non-development, power is supplied to the first static elimination member 64 and the second static elimination member 65 by the first static elimination power supply unit VE and the second static elimination power supply unit VF. Is called. At this time, the grid power supply unit VG1 and the grid power supply unit VG2 set the potentials of the first grid electrode 66 and the second grid electrode 67 to the ground potential (GND: 0 V). Thereby, the charge removal of the toner transport surface TS can be performed more stably.

  In addition, either one of the first static elimination member 64 and the second static elimination member 65 may be omitted. Alternatively, a plurality of charge removal members may be arranged on either the upstream side or the downstream side in the toner transport direction from the closest position P0.

  Further, the neutralizing member can be provided so as to face a facing region (a region in the vicinity of the closest position P0) that is a region facing the photosensitive drum 3 on the toner transport surface TS. In this case, by appropriately setting the shape of the static elimination member, the static elimination member can be favorably disposed in the facing region without hindering development of the electrostatic latent image.

  Moreover, the static elimination member may be comprised only from the grid electrode. In this case, development of the electrostatic latent image is hindered by appropriately adjusting the shape of the grid electrode (the thickness of the wire-like members constituting the grid, the distance between the wire-like members or the mesh size, etc.). Accordingly, the charge eliminating member can be disposed below the toner passage hole 61d.

(4) In the above-described embodiment, the waveform of the voltage generated by each of the power feeding units VA to VD for conveyance is a rectangular waveform, but is a waveform of another shape such as a sine waveform or a triangular waveform. Also good.

  In the above embodiment, the four power feeding units VA to VD are provided and the phases of the voltages generated by the power feeding units VA to VD are different from each other by 90 °. The power supply unit may be provided, and the voltage generated by each conveyance power supply unit may be configured to have a phase difference of 120 °.

(5) Other than that, various modifications other than these can be made without departing from the gist 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.

1 is a side view showing a schematic configuration of a laser printer according to an 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 cross-sectional view of a portion where the toner conveyance body and the photosensitive drum shown in FIG. 2 are opposed to each other. It is the graph which showed the waveform of the voltage which the electric power feeding parts VA thru | or VD for conveyance shown by FIG. 3 generate | occur | produce. It is a front view of the 1st static elimination member shown by FIG. FIG. 4 is an enlarged side sectional view showing the vicinity of a closest position P0 in the toner conveyance body shown in FIG. 3. FIG. 10 is a side cross-sectional view showing a modification of the configuration around the first charge removal member and the second charge removal member in the toner supply device shown in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser printer 2 ... Paper conveyance mechanism 3 ... Photosensitive drum 4 ... Charger 5 ... Scanner unit 6 ... Toner supply device 7 ... Control part 21 ... Registration roller 22 ... Transfer roller 31 ... Drum body 32 ... Photosensitive layer 61 ... Toner Box 61a ... Top plate 61b ... Bottom plate 61c ... Side plate 61d ... Toner passage hole 62 ... Toner carrier 62a ... Central component 62b ... Upstream component 62c ... Downstream component 62d ... Conveying electrode 62e ... Support plate 62f ... Coating film 63 ... Agitator 64 ... first static elimination member 64a ... protrusion 65 ... second static elimination member 66 ... first grid electrode 67 ... second grid electrode A1 ... upstream side static elimination area A2 ... downstream side static elimination area C ... central axis CP1 ... opposite position CP2 ... opposite position EA ... transfer electrode EB ... transfer electrode EC ... transfer electrode ED ... transfer electrode EF1 ... electric field EF2 Electric field LB ... Laser beam LS ... Latent image forming surface P ... Paper P0 ... Closest position T ... Toner TS ... Toner conveying surface VA ... Conveying power supply unit VB ... Conveying power supply unit VC ... Conveying power supply unit VD ... Conveying power supply unit Section VE ... First neutralization power feeding section VF ... Second neutralization power feeding section VG1 ... Grid power feeding section VG2 ... Grid power feeding section

Claims (10)

A latent image forming surface that is formed in parallel with a predetermined main scanning direction and configured to form an electrostatic latent image by a potential distribution; and the latent image forming surface is a sub-surface orthogonal to the main scanning direction. An electrostatic latent image carrier configured to be movable along a scanning direction;
A developer supply device arranged to face the electrostatic latent image carrier and configured to supply the developer to the latent image forming surface in a charged state;
An image forming apparatus comprising:
The developer supply device includes:
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
The developer transport surface is parallel to the main scanning direction, the transport electrodes are provided along the developer transport surface, and the developer transport surface is disposed so as to face the electrostatic latent image carrier. Developer carrier,
Opposite the developer transport surface at the upstream side and / or downstream side in the developer transport direction from the closest position where the distance between the latent image forming surface and the developer transport surface is the shortest. And a charge removal member configured to suppress charge-up on the developer transport surface by air discharge,
A feeding unit for feeding power to the carrier electrode;
A neutralizing power feeding unit that feeds power to the static eliminating member;
When power is supplied to the charge removal member, operations of the transfer power supply unit and the charge removal power supply unit are performed so as to stop power supply of the transfer electrode located upstream of the charge removal member in the developer transfer direction. A control unit to control;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
The image forming apparatus, wherein the charge eliminating member is provided so as to face a facing area on the developer transport surface, which is a face facing the electrostatic latent image carrier. The image forming apparatus according to claim 1, wherein:
When supplying power to the charge removal member, the control unit feeds the transfer power supply unit and the charge removal power supply unit so as to supply power to the transport electrode located at the downstream side in the developer transport direction with respect to at least the charge removal member. An image forming apparatus configured to control the image forming apparatus. The image forming apparatus according to any one of claims 1 to 3 ,
An image forming apparatus, further comprising a grid electrode interposed between the developer conveying surface and the charge eliminating member. The image forming apparatus according to claim 4 .
Further comprising a grid power supply unit for supplying power to the grid electrode,
The controller is
The power supply unit for the grid is controlled to set the potential of the grid electrode to the same polarity as the charging polarity of the developer when power is supplied to the transport electrode while stopping power supply to the charge removal member. An image forming apparatus. A developer image carrying surface that is parallel to a predetermined main scanning direction and on which an image by a developer can be carried, and the developer image carrying surface moves along a sub-scanning direction orthogonal to the main scanning direction. In a developer supply device configured to be able to be supplied along a predetermined developer transport direction in a state where the developer is charged with respect to a developer image carrier to be obtained,
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
The developer transport surface is parallel to the main scanning direction, the transport electrodes are provided along the developer transport surface, and the developer transport surface is disposed so as to face the developer image carrier. A developer carrier;
Opposite to the developer transport surface at the upstream side and / or downstream side in the developer transport direction from the closest position where the distance between the developer image carrying surface and the developer transport surface is the shortest. A neutralizing member that is arranged to be capable of suppressing charge-up on the developer transport surface by air discharge;
A feeding unit for feeding power to the carrier electrode;
A neutralizing power feeding unit that feeds power to the static eliminating member;
When power is supplied to the charge removal member, the transport power supply unit and the charge removal power supply unit are operated so as to stop power supply to the transport electrode positioned upstream in the developer transport direction from the charge removal member. A control unit to control;
A developer supply apparatus comprising: The developer supply device according to claim 6 ,
The developer supply device, wherein the charge eliminating member is provided so as to face a facing area which is a face facing the developer image carrier on the developer transport surface. The developer supply device according to claim 6 or 7 , wherein
When supplying power to the charge removal member, the control unit feeds the transfer power supply unit and the charge removal power supply unit so as to supply power to the transport electrode located at the downstream side in the developer transport direction with respect to at least the charge removal member. A developer supply device configured to control the developer. The developer supply device according to any one of claims 6 to 8 , wherein
A developer supply apparatus, further comprising a grid electrode interposed between the developer transport surface and the charge eliminating member. The developer supply apparatus according to claim 9, wherein
Further comprising a grid power supply unit for supplying power to the grid electrode,
The controller is
The power supply unit for the grid is controlled to set the potential of the grid electrode to the same polarity as the charging polarity of the developer when power is supplied to the transport electrode while stopping power supply to the charge removal member. A developer supply device characterized by the above.

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