JP2011059394A - Toner carrier, developing device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner carrier capable of preventing an electric field, in which hopping of toner is performed, from being not formed by disconnection, and to provide a developing device and an image forming apparatus with the toner carrier. <P>SOLUTION: The toner carrier includes: a roller member; a plurality of electrodes provided in the roller member; and a feeding part which is electrically connected to the electrodes and in which feeding is performed by a power supply provided in the developing device; wherein the feeding part and the electrodes are electrically connected so that two or more paths, through which electricity flows from the feeding part to the electrodes, are formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toner carrier used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and a developing device and an image forming apparatus provided with the toner carrier.

  2. Description of the Related Art Conventionally, there has been known an image forming apparatus that employs a hopping development method in which toner hopped on the surface of a toner carrier is used for development. In the hopping development method, for example, the image forming apparatus described in Patent Document 1 is a cylindrical toner carrier that includes a plurality of hopping electrodes that are long in the axial direction of the toner carrier and arranged at a predetermined pitch in the circumferential direction. Have a body. Among the plurality of hopping electrodes, those at even-numbered arrangement positions are referred to as A-phase electrodes, and are provided on one end side of the toner carrying roller via an A-phase power feeding unit electrically connected to one end of the A-phase electrode. The A-phase repetitive pulse voltage is applied by supplying electricity from the A-phase power source to the A-phase electrode. On the other hand, a B-phase electrode is provided at the other end side of the toner carrying roller, and the B-phase power source is connected to one end of the B-phase electrode. The B phase repetitive pulse voltage is applied by supplying electricity to the B phase electrode. As a result, an alternating electric field is formed between the A phase electrode and the B phase electrode adjacent to each other, and the toner is hopped between the electrodes by the electrostatic force acting on the toner by the alternating electric field. Then, development is performed by attaching the hopped toner to the latent image on the latent image carrier.

  However, the path through which electricity flows from the A-phase power feeding section to the A-phase electrode and the path from which electricity flows from the B-phase power feeding section to the B-phase electrode pass through the connection portion that electrically connects one end of the electrode and the power feeding section. If there is only one path, electricity will not flow from the power feeding section to the electrode when a disconnection occurs in the middle of the path. Therefore, there arises a problem that an electric field for hopping the toner cannot be formed on the toner carrier.

  By the way, it is conceivable to use a toner carrier having a multilayer structure in which an A-phase electrode and a B-phase electrode are formed in different layers with at least one insulating layer interposed therebetween. This is a configuration in which the A-phase electrode and the B-phase electrode are arranged on the same plane as the toner carrier described in Patent Document 1, and current leakage occurs between the A-phase electrode and the B-phase electrode. This solves the problem that the electric field for hopping the toner is not formed on the toner carrier.

  In the case of using a toner carrier having a multilayer structure in which the A-phase electrode and the B-phase electrode are formed in different layers with an insulating layer interposed therebetween, similarly to the toner carrier described in Patent Document 1. A path through which electricity flows from the power source to the electrode through the power supply unit electrically connected to one end of the electrode to apply electricity to the electrode electrically connects one end of the electrode and the power supply unit. If there is only one path that passes through the connecting portion that connects to, a problem similar to that described above occurs.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner carrier that can prevent the formation of an electric field that hops toner due to disconnection, and a developing device including the toner carrier. An image forming apparatus is provided.

In order to achieve the above object, a first aspect of the present invention provides a roller member, a plurality of electrodes provided on the roller member, and a power source that is electrically connected to the electrode and provided in the developing device. And a power supply unit, wherein the power supply unit and the electrode are electrically connected so that two or more paths through which electricity flows from the power supply unit to the electrode are formed. It is what.
According to a second aspect of the present invention, in the toner carrier according to the first aspect, the plurality of electrodes include one or more first electrodes disposed on the surface of the roller member, the surface of the roller member, and the first electrode. A plurality of second electrodes disposed on an insulating layer formed on the roller member so as to cover the first electrode, and the power feeding portion is electrically connected to the first electrode. A first power feeding unit fed from a first power source provided in the developing device, and a second power feeding fed from a second power source provided in the developing device that is electrically connected to the second electrode. And electrically connecting the second power supply unit and the second electrode so that two or more paths through which electricity flows from the second power supply unit to the second electrode are formed. It is characterized by that.
According to a third aspect of the present invention, in the toner carrier of the second aspect, the second electrode is a conductive member elongated in the axial direction of the roller member, and the conductive member is disposed in the axial direction of the roller member. It is characterized by being arranged in a spiral, straight line or wavy line from one end side to the other end side.
According to a fourth aspect of the present invention, in the toner carrier of the second aspect, the second electrode is a linear conductive member having a substantially constant width and having a linear shape, a curved shape or a polygonal shape. It is characterized by this.
According to a fifth aspect of the present invention, in the toner carrier according to the third or fourth aspect, the adjacent second electrodes have contact points connected to each other by linear, curved, or polygonal conductors. Are electrically connected.
According to a sixth aspect of the present invention, in the toner carrier according to the fifth aspect, the roller member is pivotally supported by the developing device so as to be rotatable about an axis, and the contact is the rotation of the roller member. It is characterized by being parallel to the direction.
According to a seventh aspect of the present invention, in the toner carrier according to the fifth aspect, the roller member is pivotally supported by the developing device so as to be rotatable about an axis, and the contact is a rotation of the roller member. It is not parallel to the direction.
According to an eighth aspect of the present invention, in the toner carrier of the second, third, fourth, fifth, sixth or seventh aspect, the second power feeding portion is located at an end portion in the axial direction of the roller member. To do.
According to a ninth aspect of the present invention, there is provided a toner carrier having a plurality of electrodes, developer supply means for supplying a developer containing at least toner to the surface of the toner carrier, and applying a pulse voltage to the plurality of electrodes. And a hopping electric field generating means for generating an electric field for hopping the toner carried on the surface of the toner carrying body on the surface of the toner carrying body, and is carried on the surface of the toner carrying body. In the developing device that develops the latent image by transporting the toner to the developing region facing the latent image carrier and attaching the toner to the latent image on the latent image carrier, the toner carrier is Item 1, 2, 3, 4, 5, 6, 7, or 8 toner carrier is used.
According to a tenth aspect of the present invention, an image obtained by developing a latent image formed on the latent image carrier by developing the latent image by supplying a developer containing at least toner by a developing unit is obtained. In an image forming apparatus for transferring an image onto a recording material and forming an image on the recording material, the developing device according to claim 9 is used as the developing means.

  In the present invention, since the power feeding part and the electrode are electrically connected so that two or more paths through which electricity flows from the power feeding part to the electrode are formed, even if a disconnection occurs in one path, Electricity can flow from the power feeding unit to the electrode through another path. Therefore, it is possible to flow electricity from the power supply unit to the electrode more stably than the configuration in which there is only one path for electricity to flow from the power supply unit to the electrode, and the disconnection causes the toner to hop on the toner carrier. It can suppress that an electric field is no longer formed.

  As described above, according to the present invention, there is an excellent effect that it is possible to suppress the formation of an electric field that hops toner due to disconnection.

FIG. 4 is a schematic diagram of a toner carrying roller in which a conductor connecting each outer electrode is disposed at a shaft end portion of the toner carrying roller on the side opposite to the side where the power feeding unit of the toner carrying roller is provided. 1 is a schematic configuration diagram of a copier according to an embodiment. FIG. 2 is a schematic configuration diagram showing a photoconductor and a developing device in the copying machine according to the embodiment. FIG. 4 is a schematic diagram when the toner carrying roller is viewed from a direction orthogonal to the rotation axis. FIG. 4 is a partial cross-sectional view schematically showing a cross section when the toner carrying roller is cut along a plane orthogonal to the rotation axis thereof. FIG. 3A is a schematic diagram of a toner carrying roller in which outer electrodes are arranged in parallel to the toner carrying roller axial direction. (B) A schematic view of a toner carrying roller in which outer electrodes are arranged in a spiral shape. The graph which shows an example of the inner side voltage and outer side voltage which are applied to an inner side electrode and an outer side electrode, respectively. The schematic diagram when the electric power feeding structure to an inner side electrode and an outer side electrode is cut | disconnected along a roller axis | shaft. The perspective view which shows a electric power feeding structure typically. FIG. 3 is a schematic diagram of a toner carrying roller in which each outer electrode is connected only at a power feeding portion provided at a shaft end portion on one side of the toner carrying roller. The schematic diagram when the electric power feeding structure to an inner side electrode and an outer side electrode is cut | disconnected along a roller axis | shaft. The perspective view which shows a electric power feeding structure typically. (A) Schematic diagram of a toner carrying roller in which linear outer electrodes are arranged in parallel to the axial direction of the toner carrying roller. (B) A schematic view of a toner carrying roller in which a linear outer electrode is arranged in a spiral shape so as to wrap around the surface of the toner carrying roller from one end side to the other end side of the toner carrying roller. (C) A schematic view of a toner carrying roller in which a curved (wavy line) outer electrode 4 is arranged in the longitudinal direction of the toner carrying roller. (D) A schematic view of a toner carrying roller in which polygonal outer electrodes are arranged in the longitudinal direction of the toner carrying roller. (A) The figure showing the relationship between an outer side electrode and a control blade in case an outer side electrode is arrange | positioned by the linear pattern parallel to a toner carrying roller axial direction. (B) A diagram showing the relationship between the outer electrode and the regulating blade when the outer electrode is arranged in a spiral shape so as to wrap around the surface of the toner carrying roller from one end side to the other end side of the toner carrying roller. . (A) The schematic diagram of the toner carrying roller by which the outer electrode of the cross beam structure was arrange | positioned. FIG. 4B is a schematic diagram of a toner carrying roller on which outer electrodes having a well-structured girder structure are provided. (C) A schematic view of a toner carrying roller provided with a staggered outer electrode. (D) Schematic diagram of a toner carrying roller when adjacent outer electrodes are connected by a curved conductor. (E) A schematic view of a toner carrying roller when adjacent outer electrodes are connected by a linear conductor disposed obliquely with respect to the rotation direction of the toner carrying roller. (F) Schematic diagram of a toner carrying roller when adjacent outer electrodes are connected by a polygonal linear conductor. (A) A schematic diagram of a toner carrying roller showing a first example in which outer electrodes are arranged in a spiral shape and adjacent outer electrodes are connected to each other by a conductor. (B) A schematic view of a toner carrying roller showing a second example in which outer electrodes are arranged in a spiral shape and adjacent outer electrodes are connected to each other by a conductor. (C) Schematic diagram of a toner carrying roller showing a third example in which outer electrodes are arranged in a spiral and adjacent outer electrodes are connected to each other by a conductor. (D) A schematic diagram of a toner carrying roller showing a fourth example in which outer electrodes are arranged in a spiral shape and adjacent outer electrodes are connected to each other by a conductor. (E) Schematic diagram of a toner carrying roller when adjacent outer electrodes of curved (wavy line) outer electrodes are connected to each other by a conductor. (F) Schematic diagram of the toner carrying roller when adjacent outer electrodes of polygonal outer electrodes are connected to each other by a conductor.

  FIG. 2 is a schematic configuration diagram of a digital copying machine (hereinafter simply referred to as a copying machine) according to an embodiment of the present invention. A bundle of documents placed on the document tray 202 in the ADF 201 with the document image side up is fed from the top document to a predetermined position on the contact glass 206 when the print key on the operation unit is pressed. Sent. The fed original is read by the reading device 250 on the image data of the original on the contact glass 206, and is then discharged to the discharge port A (discharge port at the time of reverse document discharge) by the feeding belt 204 and the reverse driving roller. Further, when it is detected that there is a next document on the document tray 202, it is fed onto the contact glass 206 in the same manner as the previous document.

  The transfer sheets stacked on the first tray 208, the second tray 209, and the third tray 210 are fed by the first paper feeding device 211, the second paper feeding device 212, and the third paper feeding device 213, respectively, and are vertically conveyed. It is conveyed to a position where it abuts on the photoreceptor 215 by the device 214. The image data read by the reading device 250 is written on the photosensitive member 215 by the laser from the writing device 257, and a toner image is formed by passing through the developing device 227. Then, the toner image on the photosensitive member 215 is transferred while the transfer paper is conveyed by the conveying belt 216 at the same speed as the rotation of the photosensitive member 215. Thereafter, the image is fixed by the fixing device 217 and conveyed to the paper discharge device 218. The transfer paper conveyed to the paper discharge device 218 is discharged to the paper discharge tray 219 when the staple mode is not performed.

  By using the toner carrier of the present invention in the developing device 227, the developer can be hopped with a small amount of power even if two-phase electrodes are formed on different surfaces, and a highly reliable and long-life toner. An image forming apparatus provided with a developing device having a carrier can be provided.

  FIG. 3 is a schematic configuration diagram showing the photosensitive member 215 and the developing device 227 in the copying machine according to the embodiment. In the figure, a drum-shaped photoconductor 215 is rotationally driven in a clockwise direction in the drawing by a driving means (not shown). A developing device 227 having a toner carrying roller 2 as a toner carrying member is disposed on the right side of the photoconductor 215 in the drawing.

  The developing device 227 includes a toner supply roller 18 and a regulation blade 31 in addition to the toner carrying roller 2. The toner supply roller 18 having a sponge surface carries the toner contained in the developing device 227 on the roller surface while being driven to rotate counterclockwise in the figure by a driving means (not shown). In the drawing, an example in which the rotation direction of the toner supply roller 18 is set to a direction in which the surface is moved in a direction opposite to the toner carrying roller 2 at a portion facing the toner carrying roller 2 is shown. On the contrary, the surface may be set to move in the same direction as the toner carrying roller 2 at the facing portion.

  A supply bias is applied to the rotating shaft member made of metal of the toner supply roller 18 by a supply bias power source 24. On the other hand, the toner carrying roller 2 is formed with a plurality of inner electrodes and outer electrodes to be described later, and repetitive pulse voltages (an inner voltage and an outer voltage to be described later) are applied to these electrodes by pulse power supplies 25A and 25B. . The average value of these pulse voltages is larger than the supply bias described above on the side opposite to the toner charging polarity. As a result, an electric field for electrostatically moving the toner from the former to the latter is formed between the toner supply roller 18 and the toner carrying roller 2.

  The toner carried on the surface of the toner supply roller 18 is supplied from the toner supply roller 18 to the toner carrying roller 2 at a contact portion between the toner supply roller 18 and the toner carrying roller 2. The supply amount at this time can be adjusted by the magnitude of the supply bias. The supply bias may be a DC voltage, an AC voltage, or a bias in which the AC voltage is superimposed on the DC voltage.

  The toner supplied onto the surface of the toner carrying roller 2 circulates as the toner carrying roller 2 rotates counterclockwise in the figure while hopping on the surface of the toner carrying roller 2 for the reason described later. . On the surface of the toner carrying roller 2, a cantilever-supporting regulation blade 31 is disposed at a position after passing through the portion facing the toner supply roller 18 and before entering the developing region facing the photoreceptor 215. Has been. When toner that moves in the counterclockwise direction in the figure as the roller rotates while hopping on the surface of the toner carrying roller 2 enters between the toner carrying roller 2 and the regulating blade 31, the regulating blade The toner on the toner carrying roller 2 is thinned by 31 and the amount of toner is regulated. Thereafter, when the toner carrying roller 2 rotates and passes between the toner carrying roller 2 and the regulating blade 31, the toner on the toner carrying roller 2 is transported to the developing region while hopping again on the surface of the toner carrying roller. Is done.

  The toner carrying roller 2 exposes a part of the outer peripheral surface from an opening provided in the casing 11 of the developing device 227. This exposed portion faces the photoreceptor 215 with a gap of several tens to several hundreds [μm]. The position where the toner carrying roller 2 and the photosensitive member 215 are opposed to each other in this way is a developing area in the copying machine. The toner transported to the development area while hopping on the surface of the toner carrying roller 2 is electrostatic latent on the surface of the photosensitive member due to a developing electric field between the toner carrying roller 2 and the electrostatic latent image on the photosensitive member 215. It adheres to the image area and is developed. The toner that has not contributed to the development is further conveyed by the rotation of the toner carrying roller 2 while hopping, and is repeatedly used.

Next, a specific configuration of the toner carrying roller 2 in the present copying machine will be described.
FIG. 4 is a schematic view of the toner carrying roller 2 in this copying machine when viewed from a direction orthogonal to the rotation axis. For convenience of explanation, the surface layer 6 and the insulating layer 5 are not shown. FIG. 5 is a partial cross-sectional view schematically showing a cross section of the toner carrying roller 2 in this copying machine when cut along a plane orthogonal to the rotation axis. The toner carrying roller 2 of the present copying machine is constituted by a hollow roller member, and an inner electrode 3a as an innermost electrode member or inner electrode member located on the innermost periphery thereof, and an outermost electrode on the outermost periphery side. A comb-shaped outer electrode 4a is provided as an outermost peripheral electrode member that is positioned and to which a voltage (outer voltage) different from a voltage (inner voltage) applied to the inner electrode 3a is applied. An insulating layer 5 having a thickness of 0.2 [μm] to 100 [μm] is provided between the inner electrode 3a and the outer electrode 4a to insulate them. Moreover, the surface layer 6 as a protective layer which covers the outer peripheral surface side of the outer electrode 4a is also provided. That is, the toner carrying roller 2 of this copying machine has a four-layer structure of an inner electrode 3a, an insulating layer 5, an outer electrode 4a, and a surface layer 6 in order from the inner peripheral side.

  The inner electrode 3a also functions as a base of the toner carrying roller 2, and is a metal roller obtained by molding a conductive material such as stainless steel or aluminum into a cylindrical shape. In addition, as a configuration of the inner electrode 3a, a structure in which a conductive layer made of a metal layer such as aluminum or copper is formed on the surface of a resin roller made of polyacetal (POM), polycarbonate (PC), or the like. As a method of forming this conductive layer, a method of forming by metal plating, vapor deposition, or the like, a method of adhering a metal film to the roller surface, or the like can be considered. The outer electrode 4a is made of a conductor, and is arranged in a straight line parallel to the axial direction of the toner carrying roller as shown in FIG. 6A from one shaft end of the roller to the other shaft end. An outer electrode 4 a is disposed over the entire area of the carrying roller 2. Further, as shown in FIG. 6B, the outer electrode 4a may be arranged in a spiral shape. For example, the outer electrode 4a is a linear electrode having a diameter of 5 μm to 200 μm in the axial direction of the roller, and a plurality of patterns are linearly arranged at intervals of 20 [μm] to 500 [μm] from the axial end of the roller. Or, it is arranged in a spiral form. The insulating layer 5 is made of a resist, a photo-curing resin, a thermosetting resin, a thermoplastic resin, or the like.

  In this copying machine, the electric field generated between the inner electrode 3a and the outer electrode 4a, more specifically, the portion of the inner electrode 3a that does not face the outer electrode 4a (the inner side located between the comb teeth of the outer electrode 4a). The electric field created between the electrode 3a part) and the comb-teeth part of the outer electrode 4a is formed outside the surface layer 6, thereby hopping the toner on the toner carrying roller 2, thereby making the toner cloudy Let At this time, the toner on the toner carrying roller 2 reciprocates while flying between the surface layer portion facing the inner electrode 3a through the insulating layer 5 and the surface layer portion facing the outer electrode 4a adjacent thereto. You will be hopping.

Next, the voltage applied to the inner electrode 3a and the outer electrode 4a will be described.
An inner voltage as a first voltage and an outer voltage as a second voltage are applied to the inner electrode 3a and the outer electrode 4a on the toner carrying roller 2 from pulse power supplies 25A and 25B, respectively. A rectangular wave is most suitable for the inner voltage and the outer voltage applied by the pulse power supplies 25A and 25B. However, not limited to this, for example, a sine wave or a triangular wave may be used. Further, in this copying machine, the electrodes for forming the flare electrode have a two-phase configuration of the inner electrode 3a and the outer electrode 4a, and voltages having a phase difference π are applied to the electrodes 3a and 4a, respectively. The

FIG. 7 is a graph showing an example of the inner voltage and the outer voltage applied to the inner electrode 3a and the outer electrode 4a, respectively.
In this copying machine, each voltage is a rectangular wave, and the inner voltage and the outer voltage applied to the inner electrode 3a and the outer electrode 4a, respectively, have the same magnitude (peak-to-peak voltage Vpp) whose phases are shifted from each other by π. Voltage. Therefore, there is always a potential difference of Vpp between the inner electrode 3a and the outer electrode 4a. An electric field is generated between the electrodes due to the potential difference, and the toner hops on the surface layer 6 by the flare electric field formed outside the surface layer 6 in the electric field.
In this copying machine, the center value V0 of the inner voltage and the outer voltage is set between the image portion potential (the potential of the electrostatic latent image portion) and the non-image portion potential (the potential of the background portion). Depending on the situation.

  Here, when a potential difference is generated between the inner electrode 3a and the outer electrode 4a, an electric field is generated. Since an electric field is generated between the inner electrode 3a and the outer electrode 4a, if the thickness of the insulating layer 5 becomes too thick, the electric field becomes weak. In order to secure a sufficient electric field, it is necessary to increase the potential difference between the electrodes. There is. Therefore, a high voltage is applied to the roller, and the durability of the roller is reduced. Therefore, it is desirable to select a material having an appropriate dielectric constant and set an appropriate coat thickness for the insulating layer 5 to efficiently extract an electric field without applying a high voltage.

  FIG. 8 is a schematic diagram of the power feeding configuration to the inner electrode 3a and the outer electrode 4a in the copying machine when cut along the roller axis. FIG. 9 is a perspective view schematically showing the power supply configuration. In the power feeding configuration for the inner electrode 3a and the outer electrode 4a in the present copying machine, the inner electrode 3a is integrated with the roller shaft of the toner carrying roller 2, and the end surface of the roller shaft serves as the power feeding portion 3b. A power supply brush 7 as a first power supply member connected to the pulse power supply 25A is in contact with the power supply unit 3b configured by the roller shaft end face. On the other hand, the surface layer 6 is not provided at one end portion of the outer peripheral surface of the toner carrying roller 2, and one end portion of the outer electrode 4a on the outer peripheral surface of the toner carrying roller 2 is exposed, and this exposed surface is the power feeding portion 4b. It becomes. A power feeding roller 8 serving as a second power feeding member connected to the pulse power source 25B is in contact with the power feeding unit 4b configured by the exposed surface. The power supply roller 8 is rotatably supported, and rotates along with the rotation of the toner carrying roller 2 while being in contact with the power supply unit 4b.

  Further, as in the present copying machine, a method in which a part of the outer electrode 4a is exposed on the outer peripheral surface of the toner carrying roller 2 and the exposed portion is used as a power supply portion 4b to contact the second power supply member to supply power. When employed, the power supply portion 4b is preferably positioned on the outer side in the axial direction than the development width on the toner carrying roller 2 (region width on which the electrostatic latent image can be formed on the photosensitive member). It is. This is because when the power supply unit 4b is positioned within the development width, the toner crushed between the toner carrying roller 2 and the power supply unit 4b contributes to the development, and development failure occurs in that portion. More preferably, it is desirable that the power supply unit 4b be positioned on the outer side in the axial direction with respect to the toner supply width (region width in which toner is supplied from the toner supply sleeve 19) on the toner carrying roller 2. This is because when the power supply unit 4b is positioned within the toner supply width, a large amount of toner is interposed between the toner carrying roller 2 and the power supply unit 4b, and power supply failure is likely to occur. In the present copying machine, the power feeding unit 4b is configured to be positioned on the outer side in the axial direction with respect to the toner supply width on the toner carrying roller 2. Further, in this copying machine, a toner seal (not shown) is provided on the axially central side of the power supply unit 4b located at one end of the roller so that the toner within the toner supply width does not adhere to the power supply unit 4b.

  In this copying machine, as the second power supply member, the power supply roller 8 that rotates along with the power supply unit 4b is used. However, the present invention is not limited to this. For example, a conductive brush or a conductive leaf spring may be used. Good. In addition, when using the 2nd electric power feeding member which slides with respect to the electric power feeding part 4b like an electroconductive brush or an electroconductive leaf | plate spring, in order to suppress abrasion of the contact part with the electric power feeding part 4b, conductive grease etc. It is good to fill.

  In this copying machine, the case where the power feeding portion of the inner electrode 3a is the end surface of the roller shaft has been described. However, the present invention is not limited thereto, and the peripheral surface of the roller shaft or the end surface of the roller main body may be used as the power feeding portion.

  Here, for example, Japanese Patent Application Laid-Open No. 3-21967 discloses a precharging means for precharging the developer conveyed by the toner carrier in a developing device that drives the carrier and conveys the developer to the latent image carrier. And a developing device characterized in that an electric field curtain generating means for applying an electric field curtain is provided on the toner carrier.

  Japanese Patent Laid-Open No. 2007-133376 includes a surface-movable toner carrier having an electrode pattern having a plurality of electrodes arranged in a predetermined direction in a state of being insulated from each other. Development on the surface of the toner carrier is caused by generating a potential difference between the odd-numbered electrode group, which is an aggregate of odd-numbered electrodes, and the even-numbered electrode group, which is an aggregate of even-numbered electrodes. In the developing device that moves the agent between the electrodes and transports it to the position facing the latent image carrier by moving the surface of the toner carrier and adheres it to the latent image on the latent image carrier, the odd-numbered electrodes and even-numbered electrodes A developing device is disclosed in which the developer on the surface of the toner carrying member is moved between the electrodes by applying pulse voltages that are out of phase with each other.

  Furthermore, the outer periphery includes a plurality of types of electrode members to which different voltages are applied, the plurality of types of electrode members are arranged at different positions in the normal direction of the outer peripheral surface, and an insulating layer is interposed between the electrode members. A toner carrier for conveying the developer carried on the surface to the development area has also been proposed.

  In order to realize these proposed devices, a roller-like component having an electrode pattern formed on the surface with a fine pitch is required as a toner carrier. The formation of an electrode pattern is particularly important for this roller-shaped part, and there is a plate printing method represented by screen printing as a feasible technique. In this method, a conductive paste is printed on a substrate instead of printing ink using a plate on which an electrode pattern is formed, and then heated and fired to form an electrode pattern. Since the plate printing method requires a plate, it is not suitable for the production of a small variety of products, but the mass production can be expected to reduce the cost.

  Another technique is an ink jet method. In this method, conductive ink is ejected onto a substrate on an on-demand basis using an inkjet head, a pattern is formed, and then heated and baked to form an electrode pattern. ing.

  As another technique, there is a pattern forming method using so-called photolithography. This is because the photosensitive material formed on the substrate surface is selectively exposed to form a pattern, and the metal film previously formed on the substrate surface is removed according to this pattern opening, or this In this method, an electrode pattern is formed by depositing a metal film according to a pattern opening. This is a method capable of forming a fine and highly accurate pattern.

However, the toner carriers constituting the developing devices disclosed in JP-A-3-21967 and JP-A-2007-133376 all have two-phase electrodes on the same surface. Therefore, even if a short circuit occurs between any adjacent electrodes, there is a problem that no potential difference occurs between all the electrodes, and the developer cannot be hopped.
Each electrode has a pattern extending in the longitudinal direction of the toner carrier and is connected to power sources of different phases from both ends. Therefore, even if any electrode is disconnected, there is no voltage in the vicinity. There is a problem that the developer cannot be hopped without being applied.

  If the roller is configured such that the two-phase electrodes are formed on different surfaces separated by an insulating layer, the roller is particularly resistant to short circuits between adjacent electrodes in the same plane and current leakage between the two-phase electrodes. This structure is stronger than the structures disclosed in Kaihei 3-21967 and JP-A-2007-133376.

  More specifically, in order to realize development without density unevenness by the hopping development method, the arrangement pitch of the electrodes on the toner carrier needs to be as small as several tens [μm]. However, if a pulse voltage having a large amplitude is applied to the electrodes arranged at a minute pitch for good hopping of the toner, current leaks easily between the electrodes. Specifically, this leak occurs as follows. That is, in the toner carrier, an insulating material is interposed between the A-phase electrode and the B-phase electrode, which are two-phase electrodes arranged along a predetermined gap along the surface of the insulating substrate. . By interposing an insulating material in the facing region between the A-phase electrode and the B-phase electrode, the occurrence of discharge between the two electrodes is suppressed. However, the A phase electrode, the B phase electrode, and the insulating material are all formed on the same plane as the surface of the insulating base, and the interface between the A phase electrode and the insulating base, the insulating material and the insulating base, And the interface between the B-phase electrode and the insulating substrate are continuously connected. When a pulse voltage with a large amplitude is applied to at least one of the A-phase electrode and the B-phase electrode, a discharge between the electrodes may occur at the continuous interface, causing current leakage. . When such a leak occurs, there is no potential difference between the A-phase electrode and the B-phase electrode, and an electric field for hopping the toner is not formed on the toner carrier.

  In view of this, it is conceivable to use a toner carrier having a multilayer structure in which the A-phase electrode and the B-phase electrode are formed in different layers with at least one insulating layer interposed therebetween. In this toner carrier, a metal layer is coated over the entire surface of the cylindrical substrate, and this metal layer functions as an A-phase electrode. On the surface of the A-phase electrode, an insulating layer made of resin is laminated. Further, on the surface of the insulating layer, a plurality of B-phase electrodes that are long in the longitudinal direction of the toner carrier and arranged at a predetermined pitch in the circumferential direction are formed. The A-phase electrode is one large cylindrical electrode. However, in the circumferential direction of the toner carrier, there are A-phase electrodes between a plurality of B-phase electrodes arranged at a predetermined pitch. For this reason, on the surface of the toner carrier, it is possible to hop toner between a plurality of B-phase electrodes and portions corresponding to the B-phase electrodes in the A-phase electrodes. In addition, a large cylindrical A-phase electrode and a plurality of B-phase electrodes are formed in separate layers with an insulating layer interposed therebetween, so that the A-phase electrode and the B-phase electrode are connected at a continuous interface. It has a structure that cannot be connected. Therefore, even when a pulse voltage having a relatively large amplitude is applied, the occurrence of discharge between the A-phase electrode and the B-phase electrode can be suppressed, and current leakage can be suppressed.

  As a method of manufacturing this roller, a photolithography method, a plate printing method such as screen printing and gravure printing, an ink jet method, and the like are conceivable.

  Although these methods show good productivity for flat plates, none of them is a stable method for rollers, and the wiring pattern of the rollers may break. For example, in plate printing such as screen printing and gravure printing, the wiring pattern is easily disconnected due to a decrease in the transfer rate of the conductive paste. In the ink jet system, in principle, since ink dots are connected to form a pattern, the line width becomes non-uniform and disconnection tends to occur.

  Here, as shown in FIG. 10, in the case where power is supplied to the outer electrode 4a only from the power supply portion 4b provided at the shaft end portion on one side of the toner carrying roller 2, in any portion of the outer electrode 4a, the power supply portion When there is only one path through which electricity supplied from 4b flows, and even at one point in the middle of the path, a portion where electricity does not flow from the disconnected position to the outer electrode 4a as viewed from the power feeding unit 4b Occurs. Therefore, it becomes impossible to form an electric field for hopping the toner on the toner carrying roller in the vicinity of the outer electrode 4a in a portion where the electricity does not flow.

  Therefore, along with the improvement of the construction method, the electrode structure of the roller itself is required to have a robust electrode that is not easily broken or has little influence on the function even if the wire is broken.

[Configuration example 1]
Therefore, in this configuration example, as shown in FIG. 1, the conductor 4c that connects each outer electrode 4a to the shaft end portion of the toner carrying roller 2 opposite to the side where the power feeding portion 4b of the toner carrying roller 2 is provided. Is arranged. Thus, since at least two power supply routes from the power supply unit 4b to any part of the outer electrode 4a can be secured, even if a disconnection occurs at one point along the route, other routes that are not disconnected Since power is supplied from the power supply unit 4b to any part of the outer electrode 4a, it is possible to prevent the power supply to any part of the outer electrode 4a from being interrupted.

  The same effect can be obtained even if the power supply portion 4b is not provided only at the shaft end portion on one side of the toner carrying roller 2, but the power supply portion 4b is provided at both shaft end portions of the toner carrying roller 2, respectively. Obtainable.

  FIG. 11 is a schematic view of a power supply configuration to the inner electrode 3a and the outer electrode 4a when the power supply portion 4b of the outer electrode 4a is provided at both end portions of the toner carrying roller 2 along the roller axis. FIG. FIG. 12 is a perspective view schematically showing the power supply configuration.

  In the power feeding configuration to the inner electrode 3a and the outer electrode 4a, the inner electrode 3a is integrated with the roller shaft of the toner carrying roller 2, and the end surface of the roller shaft serves as the power feeding portion 3b. A power supply brush 7 as a first power supply member connected to the pulse power supply 25A is in contact with the power supply unit 3b configured by the roller shaft end face. On the other hand, the surface layer 6 is not provided at both end portions of the outer peripheral surface of the toner carrying roller 2, and both end portions of the outer electrode 4a on the outer peripheral surface of the toner carrying roller 2 are exposed. Become. A power feeding roller 8 serving as a second power feeding member connected to the pulse power source 25B is in contact with the power feeding unit 4b configured by the exposed surface. The power supply roller 8 is rotatably supported, and rotates along with the rotation of the toner carrying roller 2 while being in contact with the power supply unit 4b. If there are a plurality of second power supply members for applying an external voltage to the outer electrode 4a, power can be supplied by another second power supply member even if some of the second power supply members have poor power supply due to poor contact. Therefore, stable power feeding can be performed.

  Further, as in the present copying machine, a method in which a part of the outer electrode 4a is exposed on the outer peripheral surface of the toner carrying roller 2 and the exposed portion is used as a power supply portion 4b to contact the second power supply member to supply power. When employed, the power supply portion 4b is preferably positioned on the outer side in the axial direction than the development width on the toner carrying roller 2 (region width on which the electrostatic latent image can be formed on the photosensitive member). It is. This is because when the power supply unit 4b is positioned within the development width, the toner crushed between the toner carrying roller 2 and the power supply unit 4b contributes to the development, and development failure occurs in that portion. More preferably, it is desirable that the power supply unit 4b be positioned on the outer side in the axial direction with respect to the toner supply width (region width in which toner is supplied from the toner supply sleeve 19) on the toner carrying roller 2. This is because when the power supply unit 4b is positioned within the toner supply width, a large amount of toner is interposed between the toner carrying roller 2 and the power supply unit 4b, and power supply failure is likely to occur.

  As an arrangement configuration of the outer electrode 4a with respect to the toner carrying roller 2, a linear outer electrode 4a as shown in FIG. 13A is arranged in the longitudinal direction of the toner carrying roller 2 in parallel with the axial direction of the toner carrying roller 2. 13 or a spiral that wraps the linear outer electrode 4a around the surface of the toner carrying roller 2 from one end side to the other end side of the toner carrying roller 2 as shown in FIG. You may arrange in a shape. Further, a curved (wavy line) outer electrode 4a as shown in FIG. 13C may be arranged in the longitudinal direction of the toner carrying roller 2, or a polygonal outer side as shown in FIG. 13D. The electrode 4 a may be disposed in the longitudinal direction of the toner carrying roller 2, and the curved or polygonal outer electrode 4 a is arranged on the surface of the toner carrying roller 2 from one end side to the other end side of the toner carrying roller 2. You may arrange | position in the spiral shape which wraps around.

  FIG. 14 is a diagram showing the relationship between the outer electrode 4 a and the regulating blade 31. As shown in FIG. 14A, the regulating blade 31 is disposed in the vicinity of the toner carrying roller 2, but the outer electrode 4a is disposed in a linear pattern parallel to the axial direction of the toner carrying roller. As the toner carrying roller 2 rotates, there is a difference in height between the portion where the outer electrode 4a is present and the portion where the outer electrode 4a is not present on the surface of the toner carrying roller 2 passing through the portion facing the regulating blade 31. The pressing force is changed by the toner between the toner 31 and the toner carrying roller 2, and a load is repeatedly generated on the outer electrode 4 a, or the lifting force is fluctuated on the regulation blade 31. When the load is repeatedly applied to the outer electrode 4a, the durability of the outer electrode 4a is lowered, and the possibility that the outer electrode 4a is disconnected during use is increased. Further, when the pushing force of the regulating blade 31 fluctuates, the interval between the toner carrying roller 2 and the regulating blade 31 fluctuates, and the regulation amount of the toner on the toner carrying roller 2 by the regulating blade 31 cannot be made constant. Image reproducibility deteriorates.

  Therefore, as shown in FIG. 14B, the outer electrode 4 a is not a straight line parallel to the axial direction of the toner carrying roller 2, but the surface of the toner carrying roller 2 from one end side to the other end side of the toner carrying roller 2. Since the outer electrode 4a is arranged in a spiral shape so as to be wound around the outer periphery of the toner carrying roller 2, some part of the outer electrode 4a always has a certain distance from the regulating blade 31 even when the toner carrying roller 2 rotates. Such a variation in the repeated load on the outer electrode 4a and the pushing force of the regulating blade 31 can be minimized. Accordingly, it is possible to prevent the outer electrode 4a from being disconnected or the image reproducibility from being deteriorated accordingly.

[Configuration example 2]
In order to suppress power supply failure from the power supply unit 4b to the outer electrode 4a due to the disconnection as described above, an arbitrary part of the outer electrode 4a is electrically connected to the power supply unit 4b through a plurality of paths as described above. It should be. In order to secure such a plurality of paths, the adjacent outer electrodes 4a need only be electrically connected at a plurality of locations in the toner carrying roller axial direction.

  For example, adjacent outer electrodes 4a are connected by a linear conductor 4d, and the outer electrode 4a having a cross-girder structure as shown in FIG. 15 (a), or a cross-girder structure having a spacing as shown in FIG. 15 (b). By using the outer electrode 4a, the outer electrode 4a having a staggered structure as shown in FIG. 15C, or the like, it is possible to suppress power supply failure from the power supply portion 4b to the outer electrode 4a due to disconnection as described above. . Further, if the contact point at which the adjacent outer electrodes 4a are connected by the conductor 4d is arranged in parallel with the rotation direction of the toner carrying roller 2, it does not require time and labor for manufacturing the toner carrying roller 2 and is relatively inexpensive. Resistance to disconnection can be improved.

  However, when the contact point is arranged in parallel with the rotation direction of the toner carrying roller 2, a streak may appear in the rotation direction of the toner carrying roller 2 during development due to the relationship between the toner and the outer electrode 4a. Such streaks may cause image defects during printing.

  Therefore, the adjacent outer electrodes 4a are connected by a curved or linear conductor 4d, and the contact is arranged not parallel to the rotation direction of the toner carrying roller 2, thereby suppressing the generation of streaks as described above. Image quality can be improved. For example, as shown in FIG. 15 (d), adjacent outer electrodes 4a are connected by a curved conductor 4d, or as shown in FIG. 15 (e), adjacent outer electrodes 4a are connected in the rotation direction of the toner carrying roller 2. As described above, if the linear conductors 4d arranged obliquely are connected, or the adjacent outer electrodes 4a are connected by polygonal linear conductors 4d as shown in FIG. It is possible to suppress power supply failure from the power supply unit 4b to the outer electrode 4a due to a severe disconnection, and to ensure image quality.

  Also, as shown in FIGS. 16A, 16B, 16C, and 16D, the surface of the toner carrying roller 2 from one end side to the other end side of the toner carrying roller 2 Even in the configuration in which the outer electrode 4a is arranged in a spiral shape so as to be wound around, the outer electrodes 4a adjacent to each other are connected to each other by a conductor 4d, or the outer side of a curved (wavy line) shape as shown in FIG. The adjacent outer electrode 4a of the electrode 4a or the polygonal outer electrode 4a as shown in FIG. 16 (f) may be connected to each other by a conductor 4d.

  Further, when the outer electrode 4a and the conductor 4d connecting the adjacent outer electrodes 4a are respectively polygonal, a honeycomb shape (not shown) is formed by the outer electrode 4a and the conductor 4d connecting the adjacent outer electrodes 4a. Therefore, it is possible to suppress power supply failure from the power supply portion 4b to the outer electrode 4a due to the disconnection as described above.

  Further, as shown in FIG. 15 and FIG. 16, by adopting a configuration in which a plurality of contacts where adjacent outer electrodes 4a are connected by conductors 4d are employed, no matter where the outer electrode 4a rotates, the toner carrying roller 2 rotates. Since such a portion is always in a fixed distance relationship with the regulating blade 31, it is possible to minimize the above-described repeated load on the outer electrode 4 a and fluctuations in the pushing force of the regulating blade 31. Accordingly, it is possible to prevent the outer electrode 4a from being disconnected or the image reproducibility from being deteriorated accordingly.

As described above, according to the present embodiment, the roller member, the inner electrode 3a that is one or more first electrodes disposed on the surface of the roller member, and the roller member so as to cover the roller member surface and the inner electrode 3a. The insulating layer 5 formed thereon, the outer electrode 4a that is a plurality of second electrodes disposed on the insulating layer 5, and the inner electrode 3a are electrically connected to each other and provided in the developing device 227. A power feeding unit 3b that is a first power feeding unit fed from one power source, and a second power feeding unit that is electrically connected to the outer electrode 4a and fed from a second power source provided in the developing device 227. In the toner carrying roller 2 that is a toner carrying body including a certain power feeding unit 4b, the power feeding unit 4b and the outer electrode 4a are formed such that two or more paths through which electricity flows from the power feeding unit 4b to the outer electrode 4a are formed. Are electrically connected to each other in one route. Even disconnection occurs, it is possible to electrify the outer electrode 4a from the power supply unit 4b through other routes. Therefore, it is possible to flow electricity more stably from the power supply unit 4b to the outer electrode 4a than the configuration in which there is only one path for electricity to flow from the power supply unit 4b to the outer electrode 4a. 2 can be prevented from forming an electric field for hopping the toner. Further, since the inner electrode 3a and the outer electrode 4a are formed on the roller member at different levels with the insulating layer 5 interposed therebetween, the inner electrode 3a and the outer electrode 4a are not connected by a continuous interface. Become a structure. Thereby, it is possible to suppress current leakage between the inner electrode 3a and the outer electrode 4a. Therefore, it is possible to suppress the occurrence of the leak and the occurrence of a potential difference between the inner electrode 3a and the outer electrode 4a, and the generation of an electric field for hopping the toner on the toner carrying roller 2.
According to the present embodiment, the outer electrode 4a is a conductive member that is long in the axial direction of the roller member, and the conductive member spirals from one end side to the other end side in the roller member axial direction. Since the outer electrode 4a is regularly arranged over the entire surface of the toner carrying member, the electric field can be generated stably and uniformly.
Further, according to the present embodiment, the outer electrode 4a is a linear conductive member having a substantially constant width and a linear shape, a curved shape, or a polygonal shape. Since the outer electrodes 4a are regularly arranged, a stable and uniform electric field can be generated.
Further, according to the present embodiment, adjacent outer electrodes 4a have contacts connected to each other by linear, curved, or polygonal conductors 4d, and the adjacent outer electrodes 4a are electrically connected to each other. A path through which electricity flows from the power feeding portion 4b to the outer electrode 4a through the other outer electrode 4a located adjacent to the electrode 4a can be formed.
Further, according to the present embodiment, the roller member is pivotally supported by the developing device 227 so as to be rotatable about the axis, and the contact point is parallel to the rotation direction of the roller member, so that the toner It is possible to improve the resistance to disconnection at a relatively low cost without any trouble in manufacturing the carrier roller 2.
Further, according to this embodiment, the roller member is pivotally supported by the developing device 227 so as to be rotatable about the axis, and the contact point is not parallel to the rotation direction of the roller member. Generation of such streaks can be suppressed and image quality can be improved.
Further, according to the present embodiment, since the power feeding portion 4b is located at the axial end portion of the roller member, it is possible to suppress the occurrence of development failure or power feeding failure as described above. Further, a stable electric field can be formed from the central portion to the peripheral portion except for the axial end portion of the toner carrying roller 2.
Further, according to the present embodiment, a toner carrier having a plurality of electrodes, a developer supply means for supplying a developer containing at least toner to the surface of the toner carrier, and applying a pulse voltage to the plurality of electrodes And a hopping electric field generating means for generating an electric field for hopping the toner carried on the surface of the toner carrying body on the surface of the toner carrying body, and latently carrying the toner carried on the surface of the toner carrying body. In the developing device 227 that develops the latent image by transporting it to a developing area facing the image carrier and attaching the toner to the latent image on the latent image carrier, the toner carrier roller 2 of the present invention is used as the toner carrier. Is used to suppress the occurrence of an electric field for hopping the toner on the toner carrying roller 2 due to the disconnection, and development defects such as density unevenness can be prevented. It can be suppressed Jill's.
Further, according to the present embodiment, the latent image formed on the latent image carrier is supplied with a developer containing at least toner by a developing unit, and an image obtained by developing the latent image is finally obtained. In an image forming apparatus that forms an image on a recording material by transferring the toner onto the recording material, the developing device 227 including the toner carrying roller 2 of the present invention is used as the developing unit. It is possible to suppress the occurrence of an electric field for hopping the toner on the carrying roller 2, to suppress development defects such as density unevenness, and to perform good image formation.

2 Toner carrying roller 3a Inner electrode 3b Power supply unit 4a Outer electrode 4b Power supply unit 5 Insulating layer 6 Surface layer 7 Power supply brush 8 Power supply roller 11 Casing 18 Toner supply roller 19 Toner supply sleeve 24 Supply bias power supply 25A Pulse power supply 25B Pulse power supply 31 Regulation blade 202 Document tray 204 Feed belt 206 Contact glass 208 Tray 209 Tray 210 Tray 211 Paper feed device 212 Paper feed device 213 Paper feed device 214 Vertical transport device 215 Photoconductor 216 Transport belt 217 Fixing device 218 Paper discharge device 219 Paper discharge tray 227 Developing device 250 Reading device 257 Writing device

JP-A-3-21967 JP 2007-133376 A

Claims (10)

A roller member;
A plurality of electrodes provided on the roller member;
In a toner carrier comprising: a power supply unit electrically connected to the electrode and fed from a power source provided in the developing device;
A toner carrier, wherein the power supply unit and the electrode are electrically connected so that two or more paths through which electricity flows from the power supply unit to the electrode are formed. The toner carrier according to claim 1.
The plurality of electrodes include one or more first electrodes disposed on the surface of the roller member, and an insulating layer formed on the roller member so as to cover the surface of the roller member and the first electrode. A plurality of second electrodes disposed above,
The power supply unit is electrically connected to the first electrode and supplied with power from a first power source provided in the developing device. The power supply unit is electrically connected to the second electrode and connected to the developing device. And a second power feeding unit fed from a second power source provided in
The second power feeding unit and the second electrode are electrically connected so that two or more paths through which electricity flows from the second power feeding unit to the second electrode are formed. Toner carrier. The toner carrier according to claim 2, wherein
The second electrode is a conductive member elongated in the axial direction of the roller member, and the conductive member is spirally, linearly or wavy from the one end side to the other end in the roller member axial direction. A toner carrier characterized by being disposed. The toner carrier according to claim 2, wherein
The toner carrier, wherein the second electrode is a linear conductive member having a substantially constant width and having a linear shape, a curved shape, or a polygonal shape. The toner carrier according to claim 3 or 4,
A toner carrier, wherein adjacent second electrodes have contact points connected by linear, curved, or polygonal conductors, and adjacent second electrodes are electrically connected. The toner carrier according to claim 5, wherein
The roller member is pivotally supported by the developing device so as to be rotatable about the axis.
The toner carrier, wherein the contact point is parallel to a rotation direction of the roller member. The toner carrier according to claim 5, wherein
The roller member is pivotally supported by the developing device so as to be rotatable about the axis.
The toner carrier, wherein the contact point is not parallel to the rotation direction of the roller member. The toner carrier according to claim 2, 3, 4, 5, 6 or 7,
The toner carrier, wherein the second power supply unit is located at an axial end of the roller member. A toner carrier having a plurality of electrodes;
Developer supply means for supplying a developer containing at least toner to the surface of the toner carrier;
Hopping electric field generating means for generating on the surface of the toner carrier an electric field for hopping the toner carried on the surface of the toner carrier by applying a pulse voltage to the plurality of electrodes,
A developing device that develops the latent image by transporting the toner carried on the surface of the toner carrying member to a developing region facing the latent image carrying member and attaching the toner to the latent image on the latent image carrying member. In
A developing device using the toner carrier of claim 1, 2, 3, 4, 5, 6, 7, or 8 as the toner carrier. An image obtained by developing the latent image by supplying a developer containing at least toner to the latent image formed on the latent image carrier is finally transferred onto a recording material. In an image forming apparatus for forming an image on the recording material,
An image forming apparatus using the developing device according to claim 9 as the developing unit.

Images