JP2007155822A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a current from leaking from a covered conductor 79, connected to a high voltage power source circuit, to a front metal plate 73, on which the covered conductor 79 is disposed, while avoiding a decrease in the degree of freedom of layout or an increase in the size of the apparatus, which results from disposing the high voltage power source circuit near a member, such as a charging roller, developing roll, or a primary transfer roller, to which a high voltage is applied. <P>SOLUTION: The covered conductor 79 conducing high voltage to the charging roller, developing roller, or primary transfer roller or secondary transfer roller from a high voltage power unit that has the high voltage power source circuit, not shown, is disposed on the surface of the front metal plate 73 while held in the groove 90a of a conductor guide member 90 formed from an insulating resin. The covered conductor 79 and the front metal plate 73 are securely separated from each other by a fixed distance. Such a configuration effectively restrains a current from leaking from a lead wire in the covered conductor 79 to the front metal plate 73 on which the covered conductor 79 is disposed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high voltage power supply circuit for supplying a high voltage to an image forming means having a latent image carrier, a developing means, etc., a covered electric wire for guiding the high voltage from the high voltage power supply circuit to the image forming means, and a part of the covered electric wire The present invention relates to an image forming apparatus provided with a metal member that holds a portion.

  Conventionally, not a power source for driving a driving source such as a motor, but a high voltage for supplying a high potential to a member such as a developing roller or causing a discharge from a charging roller or the like to an image forming means An image forming apparatus having a high-voltage power supply circuit is known. From the high-voltage power supply circuit, an AC voltage or DC voltage of about several kV is output to a high-voltage applied member such as a developing roller or a transfer bias roller via an electric wire. As the electric wire, a covered electric wire in which the surface of a conducting wire made of copper or the like is covered with a covering material made of an insulating material is used. However, at the high voltage as described above, even if a covered electric wire is placed over the surface of a grounded metal member such as a metal side plate, current may leak from the conductive wire to the metal member. When the high voltage output from the high-voltage power supply circuit includes an AC component, it is considered that the following phenomenon occurs rather than the current flowing from the conducting wire to the metal member through the covering material. That is, the conductive wire inside the covered electric wire and the metal member connected to the earth function as a capacitor, and the charge once stored therein flows in the opposite direction to that before the reversal due to the polarity reversal of the voltage. As a result, a current flowing from the metal member to the ground is generated, and it seems that the current leaks from the conductive wire to the metal member (hereinafter, including such a current flow). Called leaks). Such a phenomenon does not occur because polarity inversion does not occur in a DC voltage that does not include an AC component. However, although the cause is not clear, it has been confirmed that current leakage from the conductor of the covered wire to the metal member occurs even with a DC voltage.

  On the other hand, Patent Document 1 discloses an image forming apparatus in which a high-voltage power supply circuit is disposed in the vicinity of a photoconductor that is a high-voltage applied member, and a voltage output terminal of the high-voltage power supply circuit is pressed against a voltage input terminal of the photoconductor. Are listed. In such a configuration, since a high voltage is supplied from the high-voltage power supply circuit to the photoconductor without connecting the high-voltage power supply circuit and the photoconductor with a covered electric wire, current leakage from the copper wire of the covered electric wire to the metal member is prevented. It can be avoided.

Japanese Patent Laid-Open No. 10-39682

  However, in an image forming apparatus that forms an image by an electrophotographic process, in addition to the photosensitive member, a high voltage applied member such as a developing roller, a transfer bias roller, a charging roller, or the like that must apply a high voltage is an image forming unit. There are many in it. In the configuration of the image forming apparatus described in Patent Document 1, if it is attempted to avoid current leakage for each of them, a high-voltage power supply circuit must be provided in the vicinity thereof. For this reason, the degree of freedom in layout is deteriorated or the apparatus is enlarged.

  The present invention has been made in view of the above background, and an object thereof is to provide the following image forming apparatus. That is, the current from the covered wire connected to the high-voltage power supply circuit to the metal member is avoided while avoiding the deterioration of the degree of freedom of layout and the enlargement of the apparatus by arranging the high-voltage power supply circuit near the high-voltage applied member. This is an image forming apparatus capable of suppressing leakage.

In order to achieve the above object, the invention of claim 1 includes a latent image carrier that carries a latent image, charging means for uniformly charging the surface of the latent image carrier, and a latent image carried on the latent image carrier. An image forming unit having a developing unit that develops an image to obtain a visible image, and a transfer unit that transfers the visible image on the latent image carrier to a transfer unit; the latent image carrier, a charging unit; At least one drive source for driving the developing unit and the transfer unit, a high-voltage power supply circuit for generating a high voltage to be supplied to the image forming unit, and the high voltage from the high-voltage power supply circuit to the image forming unit In an image forming apparatus comprising a conductive wire, a covered electric wire having an insulating material coated on the conductive wire, and a metal member for holding a part of the covered electric wire, an insulating property for holding the part of the covered electric wire An electric wire holder made of a material is provided, and the part is placed through the electric wire holder. It is characterized in that the indirectly is held by the metal member.
According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the wire holder is made of an insulating resin.
The invention according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein the wire holder is provided with a groove for holding the covered wire, and the covered wire is placed in the groove. It is characterized by being held.
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, a plurality of claws for preventing the detachment of the covered electric wire from the groove are provided as the electric wire holder along the groove extending direction. It is characterized by using things.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the driving source holding body for holding the driving source, the driving force of the driving source for the latent image carrier, and the charging means. A drive unit in which a transmission mechanism holding body for holding a drive transmission mechanism for transmitting to the developing unit or the transfer unit is disposed opposite to each other with a predetermined gap; a drive power supply circuit that supplies power to the drive source; A drive wire for guiding power from the drive power supply circuit to the drive source, and indirectly holding the covered wire on the surface of the transmission mechanism holding body as the metal member via the wire holding body. In addition, the driving electric wire is held on the surface of the driving source holding body.
The invention according to claim 6 is the image forming apparatus according to any one of claims 1 to 5, wherein the charging means uniformly charges the surface of the latent image carrier by discharging from a charging member. In addition, the high-voltage power supply circuit supplies a charging voltage as the high voltage to the charging member.
The invention according to claim 7 is the image forming apparatus according to any one of claims 1 to 6, wherein the developing means develops the latent image with a developer carried on the surface of the developing member. In addition, the high-voltage power supply circuit supplies a developing voltage as the high voltage to the developing member.
The invention according to claim 8 is the image forming apparatus according to any one of claims 1 to 7, wherein the transfer unit moves the visible image on the latent image carrier toward the transfer member, and The transfer is performed on a transfer body, and the high-voltage power supply circuit supplies a transfer voltage as the high voltage to the transfer member.
The invention according to claim 9 is the image forming apparatus according to any one of claims 1 to 8, wherein the transfer means transfers the visible image transferred from the latent image carrier to the intermediate transfer member as a transfer member. The high voltage power supply circuit supplies the transfer voltage to the transfer member as the high voltage.

In these inventions, it is possible to adopt a layout in which the high voltage power supply circuit and the high voltage applied member are separated by guiding the high voltage from the high voltage power supply circuit to the high voltage applied member of the image forming means by the covered wire. Is possible. Therefore, it is possible to avoid the deterioration of the degree of freedom of layout and the enlargement of the apparatus due to the arrangement of the high voltage power supply circuit in the vicinity of the high voltage applied member.
Moreover, in these inventions, the covered electric wire is made of a metal member by interposing an electric wire holder made of an insulating material for holding the covered electric wire between the covered electric wire and the metal member for indirectly holding the covered electric wire. The distance between the conductive wire in the covered electric wire and the metal member is increased as compared with the case where the wire is held while being in contact with the metal wire. When a high voltage containing an AC component is output from a high-voltage power supply circuit, the distance between the covered wire and the metal member is increased by the interposition of the wire holder, and the electrical connection between the conductor of the covered wire and the metal member that functions as a capacitor. Reduce the capacity. Thereby, the leakage of the electric current from the conducting wire of a covered electric wire to a metal member can be suppressed. Even when a high voltage that does not include an AC component is output from the high-voltage power supply circuit, the current from the conductor of the covered wire to the metal member can be obtained by interposing the wire holder between the covered wire and the metal member. The present inventors have confirmed through experiments that the leakage of the above can be suppressed. Therefore, in either case of AC voltage or DC voltage, the leakage of current from the conductor of the covered wire to the metal member can be suppressed by interposing the wire holder between the covered wire and the metal member. it can.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described.
First, the basic configuration of the printer according to this embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating a printer according to the present embodiment. The printer shown in FIG. 1 includes four process units 1Y, 1C, 1M, and 1K for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, C, M, and K). These use Y, C, M, and K toners of different colors as image forming substances for forming an image, but the other configurations are the same. Taking a process unit 1Y for generating a Y toner image as an example, this has a photoconductor unit 2Y and a developing unit 7Y as shown in FIG. As shown in FIG. 3, the photosensitive unit 2Y and the developing unit 7Y are integrally attached to and detached from the printer body as a process unit 1Y. However, in a state where it is detached from the printer main body, as shown in FIG. 4, the developing unit 7Y as developing means can be attached to and detached from the photosensitive unit (not shown).

  In FIG. 2 described above, the photoconductor unit 2Y includes a drum-shaped photoconductor 3Y serving as a latent image carrier, a drum cleaning device 4Y, a static eliminator (not shown), a charging device 5Y, and the like.

  The charging device 5Y as charging means uniformly charges the surface of the photoreceptor 3Y that is driven to rotate in the clockwise direction in the drawing by a driving means (not shown). In the drawing, the charging roller 6Y as a charging member that is driven to rotate counterclockwise in the drawing is applied close to the photosensitive member 3Y while a charging bias is applied by a power source (not shown) to uniformly charge the photosensitive member 3Y. A charging type charging device 5Y is shown. Instead of the charging roller 6Y, a roller that contacts a charging brush may be used. Further, a charger that uniformly charges the photoreceptor 3Y by a charger method, such as a scorotron charger, may be used. The surface of the photoreceptor 3Y uniformly charged by the charging device 5Y is exposed and scanned by a laser beam emitted from an optical writing unit to be described later, and carries a Y electrostatic latent image.

  The developing unit 7Y as developing means has a first agent accommodating portion 9Y in which a first conveying screw 8Y is disposed. Further, it also has a second agent storage portion 14Y in which a toner concentration sensor (hereinafter referred to as a toner concentration sensor) 10Y composed of a magnetic permeability sensor, a second conveying screw 11Y, a developing roll 12Y, a doctor blade 13Y, and the like are disposed. . In these two agent storage portions, a Y developer (not shown) composed of a magnetic carrier and a negatively chargeable Y toner is included. The first transport screw 8Y is driven to rotate by a driving unit (not shown), thereby transporting the Y developer in the first agent storage unit 9Y from the near side to the far side in the direction perpendicular to the drawing sheet. And it penetrates into the 2nd agent accommodating part 14Y through the communication port which is not shown in the partition wall between the 1st agent accommodating part 9Y and the 2nd agent accommodating part 14Y.

  The second transport screw 11Y in the second agent storage portion 14Y is driven to rotate by a driving means (not shown), thereby transporting the Y developer from the back side to the front side in the drawing. The toner concentration of the Y developer being conveyed is detected by the toner concentration sensor 10Y fixed to the bottom of the first agent storage portion 14Y. A developing roll 12Y as a developing member is arranged in a posture parallel to the second transport screw 11Y above the second transport screw 11Y that transports the Y developer in this way. The developing roll 12Y includes a magnet roller 16Y in a developing sleeve 15Y made of a non-magnetic pipe that is driven to rotate counterclockwise in the drawing. A part of the Y developer conveyed by the second conveying screw 11Y is pumped up to the surface of the developing sleeve 15Y by the magnetic force generated by the magnet roller 16Y. Then, after the layer thickness is regulated by the doctor blade 13Y disposed so as to maintain a predetermined gap from the developing sleeve 15Y, the layer thickness is regulated and conveyed to the developing area facing the photosensitive member 3Y, and the Y for the photosensitive member 3Y is used. The Y toner is adhered to the electrostatic latent image. This adhesion forms a Y toner image on the photoreceptor 3Y. The Y developer that has consumed the Y toner by the development is returned to the second conveying screw 11Y as the developing sleeve 15Y of the developing roll 12Y rotates. And if it conveys to the near end in a figure, it will return in the 1st agent accommodating part 9Y via the communication port which is not shown in figure.

  The result of detecting the magnetic permeability of the Y developer by the toner concentration sensor 10Y is sent as a voltage signal to a control unit (not shown). Since the magnetic permeability of the Y developer shows a correlation with the Y toner density of the Y developer, the toner density sensor 10Y outputs a voltage having a value corresponding to the Y toner density. The control unit includes a RAM, in which a V Vref for Y which is a target value of the output voltage from the toner density sensor 10Y and a toner density sensor for C, M, and K mounted in another developing unit. The data of C Vtref, M Vtref, and K Vtref, which are target values of the output voltage, are stored. For the Y developing unit 7Y, the value of the output voltage from the toner density sensor 10Y is compared with the Y Vtref, and the Y toner supply device described later is driven for a time corresponding to the comparison result. By this driving, an appropriate amount of Y toner is supplied to the Y developer whose Y toner density has been reduced by the consumption of Y toner during development in the first agent storage unit 9Y. For this reason, the Y toner concentration of the Y developer in the second agent container 14Y is maintained within a predetermined range. Similar toner supply control is performed for the developers in the process units (1C, M, K) for other colors.

  The Y toner image formed on the photoreceptor 3Y is intermediately transferred to an intermediate transfer belt described later. The drum cleaning device 4Y of the photoreceptor unit 2Y removes the toner remaining on the surface of the photoreceptor 3Y after the intermediate transfer process. As a result, the surface of the photoreceptor 3Y that has been subjected to the cleaning process is neutralized by a neutralizing device (not shown). By this charge removal, the surface of the photoreceptor 3Y is initialized and prepared for the next image formation. In FIG. 1 described above, in the process units 1C, M, and K for other colors, C, M, and K toner images are similarly formed on the photoreceptors 3C, M, and K, and the intermediate transfer belt is formed. Intermediate transfer.

  An optical writing unit 20 is arranged below the process units 1Y, 1C, 1M, and 1K in the drawing. The optical writing unit 20 serving as a latent image forming unit irradiates the photoconductors 3Y, C, M, and K of the process units 1Y, C, M, and K with a laser beam L emitted based on the image information. Thereby, electrostatic latent images for Y, C, M, and K are formed on the photoreceptors 3Y, 3C, 3M, and 3K. The optical writing unit 20 deflects the laser light L emitted from the light source by the polygon mirror 21 that is rotationally driven by a motor, and passes through the photosensitive members 3Y, 3C, 3M, and 3K via a plurality of optical lenses and mirrors. Is irradiated. In place of such a configuration, an optical scanning device using an LDE array may be employed.

  A first paper feed cassette 31 and a second paper feed cassette 32 are disposed below the optical writing unit 20 so as to overlap in the vertical direction. In each of these paper feed cassettes, a plurality of recording papers P as recording members are accommodated in a stack of recording papers. The uppermost recording paper P includes a first paper feed roller 31a, The second paper feed rollers 32a are in contact with each other. When the first paper feed roller 31a is driven to rotate counterclockwise in the figure by a driving means (not shown), the uppermost recording paper P in the first paper feed cassette 31 is vertically oriented on the right side of the cassette in the figure. The paper is discharged toward the paper feed path 33 arranged so as to extend. Further, when the second paper feed roller 32 a is driven to rotate counterclockwise in the figure by a driving means (not shown), the uppermost recording paper P in the second paper feed cassette 32 is directed toward the paper feed path 33. Discharged. A plurality of transport roller pairs 34 are arranged in the paper feed path 33, and the recording paper P fed into the paper feed path 33 is sandwiched between the rollers of the transport roller pair 34 while being fed between the paper feed paths 33. 33 is conveyed from the lower side to the upper side in the figure.

  A registration roller pair 35 is disposed at the end of the paper feed path 33. The registration roller pair 35 temporarily stops the rotation of both rollers as soon as the recording paper P fed from the conveyance roller pair 34 is sandwiched between the rollers. Then, the recording paper P is sent out toward a later-described secondary transfer nip at an appropriate timing.

  Above each of the process units 1Y, 1C, 1M, and 1K, a transfer unit 40 that is endlessly moved counterclockwise in the drawing while an intermediate transfer belt 41 that is an endless moving body is stretched is disposed. The transfer unit 40 serving as transfer means includes an intermediate transfer belt 41, a belt cleaning unit 42, a first bracket 43, a second bracket 44, and the like. Further, four primary transfer rollers 45Y, 45C, 45M, 45K, a secondary transfer backup roller 46, a drive roller 47, an auxiliary roller 48, a tension roller 49, and the like are also provided. The intermediate transfer belt 41 is endlessly moved counterclockwise in the figure by the rotational driving of the driving roller 47 while being stretched by these eight rollers. The four primary transfer rollers 45Y, 45C, 45M, and 45K as transfer members sandwich the intermediate transfer belt 41 that is moved endlessly in this manner between the photoreceptors 3Y, 3C, 3M, and 1K, and perform primary transfer. A nip is formed. Then, a transfer bias having a polarity opposite to that of the toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 41. The intermediate transfer belt 41 sequentially passes through the primary transfer nips for Y, C, M, and K along with its endless movement, and on the photoreceptor 3Y, C, M, and K on the front surface. The Y, C, M, and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 41.

  The secondary transfer backup roller 46 sandwiches the intermediate transfer belt 41 with the secondary transfer roller 50 disposed outside the loop of the intermediate transfer belt 41 to form a secondary transfer nip. The registration roller pair 35 described above feeds the recording paper P sandwiched between the rollers toward the secondary transfer nip at a timing at which the recording paper P can be synchronized with the four-color toner image on the intermediate transfer belt 41. The four-color toner image on the intermediate transfer belt 41 is affected by the secondary transfer electric field formed between the secondary transfer roller 50 to which the secondary transfer bias is applied and the secondary transfer backup roller 46, and the influence of the nip pressure. The secondary transfer is batch-transferred onto the recording paper P in the secondary transfer nip. Then, combined with the white color of the recording paper P, a full color toner image is obtained.

  Untransferred toner that has not been transferred to the recording paper P adheres to the intermediate transfer belt 41 after passing through the secondary transfer nip. This is cleaned by the belt cleaning unit 42. In the belt cleaning unit 42, the cleaning blade 42a is brought into contact with the front surface of the intermediate transfer belt 41, whereby the transfer residual toner on the belt is scraped off and removed.

  A fixing unit 60 is disposed above the secondary transfer nip in the drawing. As shown in FIG. 5, the fixing unit 60 includes a pressure heating roller 61 that includes a heat source 61 a such as a halogen lamp, and a fixing belt unit 62. The fixing belt unit 62 includes a fixing belt 64 serving as a fixing member, a heating roller 63 including a heat source 63a such as a halogen lamp, a tension roller 65, a driving roller 66, a temperature sensor 67, and the like. Then, the endless fixing belt 64 is endlessly moved in the counterclockwise direction in the drawing while being stretched by the heating roller 63, the tension roller 65, and the driving roller 66. In the process of endless movement, the fixing belt 64 is heated from the back side by the heating roller 63. A pressure heating roller 61 that is rotationally driven in the clockwise direction in the drawing is in contact with the surface of the fixing belt 64 that is heated in this manner from the front side. Thereby, a fixing nip where the pressure heating roller 61 and the fixing belt 64 abut is formed.

  A temperature sensor 67 is disposed outside the loop of the fixing belt 64 so as to face the front surface of the fixing belt 64 with a predetermined gap, and the surface of the fixing belt 64 immediately before entering the fixing nip. Detect temperature. This detection result is sent to a fixing power supply circuit (not shown). The fixing power supply circuit performs on / off control of power supply to the heat source 63 a included in the heating roller 63 and the heat source 61 a included in the pressure heating roller 61 based on the detection result by the temperature sensor 67. As a result, the surface temperature of the fixing belt 64 is maintained at about 140 [°].

  In FIG. 1 described above, the recording paper P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 41 and then sent into the fixing unit 60. Then, in the process of being conveyed from the lower side to the upper side in the figure while being sandwiched between the fixing nips in the fixing unit 60, the full-color toner image is fixed by being heated or pressed by the fixing belt 64.

  The recording paper P subjected to the fixing process in this manner is discharged outside the apparatus after passing between the rollers of the paper discharge roller pair 67. A stack unit 68 is formed on the upper surface of the housing of the printer main body, and the recording paper P discharged to the outside by the discharge roller pair 67 is sequentially stacked on the stack unit 68.

  Above the transfer unit 40, four toner cartridges 100 Y, C, M, and K that store Y, C, M, and K toners are disposed. The Y, C, M, and K toners in the toner cartridges 100Y, 100C, M, and K are appropriately supplied to the developing units 7Y, C, M, and K of the process units 1Y, C, M, and K. These toner cartridges 100Y, 100C, 100M, and 100K are detachable from the printer main body independently of the process units 1Y, 1C, 1M, and 1K.

  FIG. 6 is a perspective view showing a toner cartridge 100Y for Y. In the figure, a toner cartridge 100Y includes a bottle-shaped bottle portion 101Y that stores Y toner (not shown) and a cylindrical holder portion 102Y. The holder portion 102Y rotatably holds the bottle portion 101Y while engaging the tip portion of the bottle portion 101Y so as to cover an opening (not shown) formed at the tip of the bottle portion 101Y. The bottle portion 101Y is embossed with a screw-like projection that protrudes from the outside toward the inside along the circumferential surface of 103Y. When the bottle portion 101Y is rotated by a drive system (not shown), the Y toner in the bottle portion 101Y moves along the screw-shaped protrusion from the bottle bottom side toward the bottle front end side. Then, the toner flows into the cylindrical holder portion 102Y through an opening (not shown) provided at the tip of the bottle portion 101Y as a toner container.

  A nozzle receiving port 109Y is formed on an end surface of the holder portion 102Y in the bottle axis direction. The nozzle receiving port 109Y is for receiving a later-described suction nozzle fixed to the printer main body side. On both sides of the nozzle receiving port 109Y in the figure, positioning pin receiving ports 110Y each having a slightly smaller diameter than the nozzle receiving port are formed. Each of the positioning pin receiving ports 110Y is formed at a position deviated from the rotation axis of the bottle portion 101Y, and a pin insertion passage (not shown) is provided in a direction parallel to the rotation axis direction of the bottle portion 101Y. It is formed to extend. The bottle portion 101Y is made of a resin material that is so rigid that it is not deformed by an impact when being rotated by the drive transmission gear.

  FIG. 7 is a perspective view showing a cartridge connecting portion 71Y for Y that is a part of a toner replenishing device described later. The Y cartridge connecting portion 71Y is fixed to the upper end of a flow pipe 72Y for flowing Y toner so that a suction nozzle 73Y as a pipe member extends in the horizontal direction. A toner receiving port 74Y for receiving Y toner is formed at the tip of the suction nozzle 73Y. Further, on both sides of the suction nozzle 73Y, rod-like positioning pins 75Y are respectively fixed so as to extend in the horizontal direction (direction parallel to the rotation axis of the bottle portion). A positioning pin 75Y, which is a convex portion of the cartridge connecting portion 71Y as a positioning member, has a tip protruding beyond the tip of the suction nozzle 73Y.

  When the Y toner cartridge 100Y is set on a cartridge mounting table of a toner replenishing device to be described later, first, an opening / closing door (not shown) provided on the side plate of the printer housing is opened. Then, the cartridge mounting table of the toner supply device in the housing is exposed. The cartridge mounting table is provided with four semi-cylindrical recesses in parallel for mounting four toner cartridges for Y, C, M, and K in parallel. The operator holds the toner cartridge 100Y in such a posture that the holder portion 102Y faces the head. Then, after placing the holder part 102Y on the end of the Y depression among the four depressions on the half cylinder provided on the cartridge mounting table, slide along the bottle axis of rotation so that the entire cartridge is inserted. Move. By this sliding movement, the toner cartridge 100Y is pushed to a predetermined position and set on the cartridge mounting table.

  The two positioning pins 73Y of the Y cartridge connecting portion 71Y in the toner replenishing device are fixed so that the tip ends protrude beyond the tip of the suction nozzle 73Y. And the front-end | tip part is taper rather than the rear-end side. While the toner cartridge is being inserted onto the cartridge mounting table at the time of setting, the tapered tip ends of the two positioning pins 73Y respectively enter the two positioning pin receiving ports 110Y of the toner cartridge 100Y shown in FIG. When the toner cartridge 100Y is further inserted, the rear end side that is thicker than the front end portion of the positioning pin 73Y also enters the pin receiving port 110Y. When the rear end side, which is thicker than the front end portion, enters the pin receiving port 110Y, the toner cartridge 100Y is positioned on the cartridge mounting table in the direction perpendicular to the rotational axis direction.

  When the toner cartridge 100Y is further inserted after such positioning, the suction nozzle 73Y in the cartridge connecting portion 109Y enters the nozzle receiving port 109Y of the holder portion 102Y. When the inside of the suction nozzle 73Y is pushed to a certain extent into the insertion passage (115Y) extending inside the nozzle receiving port 109Y, the setting of the toner cartridge 100Y is completed.

  The toner cartridge 100Y set in this manner meshes the gear portion 111Y formed at the front end portion of the bottle portion 101Y with a drive transmission gear (not shown) fixed to the toner replenishing device. When the drive transmission gear is driven to rotate, the bottle portion 101Y rotates while being held by the holder portion 102Y. By this rotation, the Y toner in the bottle portion 101Y is conveyed from the bottle rear end side toward the front end side and flows into the holder portion 102.

  A suction pump is connected to a region (not shown) of the flow pipe 72Y connected to the suction nozzle 73Y, and air and toner in the flow pipe 72Y are sucked by this operation. Then, the suction force is transmitted to the holder 102Y through the flow pipe 72Y and the suction nozzle 73Y. Then, the Y toner in the holder 102 is sucked into the suction nozzle 73Y and replenished into the developing unit 7Y of the Y process unit 1Y.

  Although the Y toner cartridge 100Y for storing Y toner has been described in detail, the toner cartridges for other colors (100C, M, K) have the same configuration.

  FIG. 8 is a perspective view showing a suction pump 78Y for Y among the four suction pumps for Y, C, M, and K. The suction pump 78Y is of a type called a uniaxial eccentric screw pump (commonly known as a Mono pump). The pump portion 80Y includes a rotor 81Y processed into an eccentric double screw shape using a metal or a highly rigid resin, a stator 82Y in which a double screw cavity is formed in a material such as rubber, and a resin containing these. It is made up of a made holder and the like. The suction pump 78Y includes, in addition to the pump unit 80Y, a discharge unit 83Y, a motor 84Y that rotates the rotor 81Y, and the like. When the double screw-shaped rotor 81Y rotates in the stator 82Y, a negative pressure is generated on the suction side (right side in the drawing) of the pump unit 80Y. With this negative pressure, the Y toner in the Y toner cartridge 100Y is sucked through the flow pipe 72Y and the like. Then, it reaches the pump portion 80Y of the suction pump 78Y, and is discharged from the discharge portion 83Y through the stator 82Y. The suction pumps for other colors have the same configuration.

  FIG. 9 is a perspective view showing the toner replenishing device and the surrounding configuration. The toner replenishing device 70 includes a cartridge mounting table 77, four cartridge connecting portions 71Y, C, M, and K, four suction pumps 78Y, C, M, and K, and the like. The cartridge mounting table 77 has four semi-cylindrical recesses for mounting the four toner cartridges 100Y, 100C, 100M, and 100K in parallel. A transfer unit (not shown) is disposed below the cartridge mounting table 77, and four developing units are disposed below the transfer unit. In the figure, for convenience, only the K developing unit 7K is shown among the four developing units.

  An opening / closing door for exchanging cartridges is provided on the side surface of the printer casing (not shown). When the opening / closing door is opened, the toner replenishing device 70 in the casing is exposed at the back side in the drawing. The operator sets the toner cartridges 100Y, 100C, 100M, and 100K in the toner replenishing device 70 by sliding them on the cartridge mounting table 77 so as to push the toner cartridges 100Y, 100C, 100M, and 100K in the bottle longitudinal direction from the open / close door.

  A connecting portion support plate 79 for supporting the four cartridge connecting portions 71Y, 71C, 71M, and 71K is erected on one end portion of the cartridge mounting table 77. The suction nozzles of the cartridge connecting portions 71Y, 71Y, 71C, 71M, and 71K are inserted into the nozzle insertion passages (not shown) of the toner cartridges 100Y, 100C, 100M, and 100K mounted on the cartridge mounting table 77, respectively. Suction pumps 78Y, C, M, and K are connected to the ends of the flow pipes 72Y, C, M, and K of the cartridge connecting portions 71Y, 71C, 71M, and 71K. Immediately below each suction pump 78Y, C, M, K, a toner supply port E of each developing unit is located. The Y, C, M, and K toner discharged from the discharge portions of the suction pumps 78Y, C, M, and K are supplied to the inside of the developing unit through the toner supply ports of the corresponding developing units. Although only the K developing unit 5K is shown in the drawing, Y, M, and C developing units are also provided directly under the Y, M, and C suction pumps 78Y, M, and C, respectively. positioned.

  In the printer having the above basic configuration, the process units 1Y, 1C, 1M, and 1K and the transfer unit 40 constitute image forming means for forming an image on the recording paper P.

Next, a characteristic configuration of the printer will be described.
FIG. 1 shows the printer from the front side. The rear side in the direction orthogonal to the drawing sheet is the rear side of the printer, and the front side is the front side of the printer. The left side in the figure is the left side of the printer, and the right side in the figure is the right side of the printer. A front door (not shown) that can be opened and closed is provided at the front of the printer casing. By opening the front door, the front surface of the transfer unit 40 disposed in the housing and the front surfaces of the process units 1Y, 1C, 1M, and 1K are exposed to the outside. The transfer unit 40 and the process units 1Y, 1C, 1M, and 1K can be pulled out from the printer body by sliding the printer unit from the rear side to the front side with the front surface exposed in this manner.

  FIG. 10 is a plan view showing the process units 1Y, 1C, 1M, and 1K in the printer and the surrounding configuration from above. The process units 1Y, 1C, 1M, and 1K set in the printer main body abut the rear surface of the casing against the front surface of the rear plate 70 of the printer main body. A drive unit 71 for transmitting drive force to the transfer unit 40 and the process units 1Y, C, M, and K is fixed to the rear surface of the rear plate 70 of the printer main body.

  FIG. 11 is a perspective view showing the drive unit 71. In the figure, the drive unit 71 has a metal front sheet metal 73 and a rear sheet metal 74 connected by a plurality of bar-shaped spacers 72 so as to face each other at a predetermined distance. A plurality of drive motors 75 as drive sources are fixed to the rear surface of the rear sheet metal 74, and these drive through a through hole (not shown) provided in the rear sheet metal 74, respectively. Thereby, most of the motor shaft of each drive motor 75 is located between the front sheet metal 73 and the rear sheet metal 74. The front sheet metal 73 rotatably holds each gear in a drive transmission mechanism 77 formed of a plurality of gears meshed with a driving gear (not shown) fixed to the motor shaft. Several rotation shafts in the drive transmission mechanism 77 serve as drive output shafts, and pass through through holes (not shown) provided in the front sheet metal 73 so as to protrude to the front side of the front sheet metal 73. The metal front sheet metal 73 and the rear sheet metal 74 are grounded via a ground wire (not shown).

  In FIG. 10 described above, a plurality of drive output shafts (not shown) protruding from the front sheet metal of the drive unit 71 pass through the rear plate 70 of the printer main body, and drive output gears fixed to the front ends of the drive output gears. It meshes with a drive receiving gear (not shown) provided in the transfer unit 40 and the process units 1Y, C, M, and K. Thereby, the rotational driving force of the plurality of drive motors 75 fixed to the drive unit 71 is transmitted to the transfer unit 40 and the process units 1Y, 1C, 1M, and 1K via the drive transmission mechanism (77 in FIG. 11). .

  As shown in FIG. 11, a plurality of drive wires 76 are wound around the rear surface of the rear sheet metal 74 of the drive unit 71, and one end thereof is connected to one of the plurality of drive motors 75. The other end is connected to a drive power supply circuit (not shown), and the voltage from the drive power supply circuit is supplied to the drive motor 75 via the drive wire 76. This voltage is a relatively low value such as AC 100 [V] or AC 200 [V]. With such a voltage, even if the driving electric wire 76 that is a covered electric wire is directly wound around the rear surface of the rear sheet metal 74, no current leaks from the conductive wire of the driving electric wire 76 to the rear sheet metal 74 that is a metal member. .

  In FIG. 10 shown above, a high voltage power unit 78 incorporating a high voltage power supply circuit (not shown) is disposed at a position slightly away from the drive unit 71. The high voltage power unit 78 outputs a charging bias to be applied to the charging rollers of the process units 1Y, 1C, 1M, and 1K shown in FIG. 1 and a developing bias to be applied to each developing roll. Further, a primary transfer bias for applying to each primary transfer roller 45Y, C, M, K in the transfer unit 40 and a secondary transfer bias for applying to the secondary transfer roller 50 are also output. The developing bias is an AC or DC bias having a high voltage of 700 [V] or higher. The charging bias is an AC bias having a high voltage of about 2 [kV]. The primary transfer bias and the secondary transfer bias are high voltage direct current or alternating current bias of several [kV]. These biases are applied from the high voltage power unit 78 to the developing roll, the charging roller, the primary transfer roller, or the secondary transfer roller via the covered electric wire 79.

  The covered wire 79 extending from the high-voltage power unit passes through between the front sheet metal 73 and the rear sheet metal 74 of the drive unit 71 and is connected to each process unit 1Y, C, M, K or a transfer unit (not shown). Between the front sheet metal 73 and the rear sheet metal 74, as shown in FIG. 12, it is scooped on the rear surface of the front sheet metal 73 while being held by the wire guide member 90 which is an electric wire holder fixed to the front sheet metal 73. It has been turned. The wire guide member 90 is made of an insulating resin, and is fixed to the front metal plate 73 with screws as shown in FIG. And it has the groove | channel 90a extended in a member longitudinal direction in the surface on the opposite side to the opposing surface with the front sheet metal 73, and the covered electric wire 79 is hold | maintained in the inside. Thus, a distance X corresponding to the distance between the bottom surface of the wire guide member 90 and the bottom surface of the groove is ensured between the covered wire 79 and the rear surface of the metal front sheet metal 73 connected to the ground.

  In addition, the conductor wire made of copper is included in one covered electric wire 79 so that the insulated state is maintained. In FIG. 10, only one two covered wires 79 extending from the high-voltage power unit 78 (two conductive wires inside) are shown, but in reality, 13 wires are extended. 4 for development bias of each color (Y, C, M, K), 4 for charging bias of each color, 4 for primary transfer bias of each color, and 1 for secondary transfer bias The total is 13. Of these, the four development biases are gathered as a single harness from the high voltage power unit 78 to the drive unit 71. In the drive unit 71, four are divided, and each is held by the individual wire guide member 90 on the front sheet metal 73. Similarly, the four charging biases and the four primary transfer biases are each grouped as one harness until reaching the drive unit 71, but each 4 in the drive unit 71. It is divided into books and held by individual wire guide members 90. One of the secondary transfer biases is wound around a right side plate (not shown) of the printer main body without passing through the drive unit 71 and then connected to the secondary transfer roller (50). Therefore, in FIG. 13, only one wire guide member 90 is shown. Actually, however, a total of 12 wire guides for developing bias x4, charging bias x4, and primary transfer bias x4 are used. A member 90 is fixed on the rear surface of the front sheet metal 73.

  FIG. 14 is a perspective view showing the process unit 1Y for Y from the rear surface side. A developing roll (not shown) disposed in the developing unit 7Y for Y has a metal shaft member 7aY, which protrudes outside from the rear surface of the casing of the developing unit 7Y. On the other hand, the end of a covered wire (not shown) for a Y developing bias extending from a high voltage power unit (not shown) (78 in FIG. 10) is connected to a metal terminal (not shown). When this terminal slides on the shaft member 7aY, the Y developing bias from the high voltage power unit is guided to the developing roll.

  A charging bias connector 6aY is provided on the rear surface of the casing of the photosensitive unit 2Y of the process unit 1Y. On the other hand, the end portion of the covered electric wire (not shown) for the Y charging bias extending from the high voltage power unit (not shown) is connected to an output connector (not shown). When this output connector is fitted into the charging bias connector 6aY of the photoreceptor unit 2Y, the Y charging bias from the high voltage power unit is guided to a Y charging roller (not shown). Similarly, in the process units (! C, M, K) of other colors, the developing bias and charging bias from the high-voltage power unit are guided to the developing roll and charging roller in the unit.

  FIG. 15 is a perspective view showing the transfer unit 40 from the rear side. Various rollers that stretch the intermediate transfer belt 41 of the transfer unit 40 are rotatably wound between the unit front side plate 53 and the unit rear side plate 51. On the rear surface of the unit rear side plate 51, primary transfer bias connectors 52Y, C, M connected to primary transfer rollers for Y, C, M, K (not shown) (45Y, C, M, K in FIG. 1). , K are fixed. On the other hand, the ends of the covered wires (not shown) for Y, C, M, and K extending from the high-voltage power unit (not shown) are respectively connected to output connectors (not shown). The Y, C, M, and K output connectors are fitted into Y, C, M, and K primary transfer bias connectors 52Y, C, M, and K that are fixed to the unit rear side plate 51 of the transfer unit 40. . As a result, the primary transfer bias for Y, C, M, and K from a high voltage power unit (not shown) is guided to the primary transfer roller for Y, C, M, and K.

The inventors prepared a printer testing machine provided with the circuit configuration shown in FIG. 16 in the printer having the above configuration. In the figure, one of the two conductors in the covered electric wire 79 extending from the high-voltage power unit 78 having a high-voltage power supply circuit, one conductor 79a is connected to one end of the K charging roller 6K. The other end side of the charging roller 6K is connected to the high voltage power unit 78 via the first ampermeter 151, the front sheet metal 73 of the drive unit, the other conductor 79b of the covered electric wire 79, and the second ampermeter 152. Has been. From the high-voltage power unit 78, a charging bias having VP _-P of 2 [kV] and a frequency of 1350 [Hz] is output to the two conductors 79a and 79b. The charging current that has flowed to one conductor 79 a by this output returns to the high-voltage power unit 78 via the first ampermeter 151, the front sheet metal 73, the other conductor 79 b, and the second ampermeter 152. At this time, the return current I <b> 2 returning to the high voltage power unit 78 is detected by the second ampermeter 152. Further, the charging current I1 flowing from the charging roller 6K to the front sheet metal 73 is detected by the first ampermeter 151. When there is no current leakage from the one lead wire 79a to the front sheet metal 73, the charging current I1 and the return current I2 have substantially the same value. When the return current I2 is larger than the charging current I1, the current leaks from the one conductor 79a to the front sheet metal 73 by the difference. This current is the leakage current I3 shown in FIG.

In the printer testing machine to which such a circuit configuration is added, the present inventors have prepared various heights as the wire guide member (90 in FIG. 13) for holding the covered wire 79 for the K charging bias. . An experiment was conducted to examine the relationship among the charging current I1, the return current I2, and the leakage current I3 while sequentially replacing these wire guide members. The results are shown in Table 1 below.

  In Table 1, in the experiment of Experiment No. 1, without covering the wire guide member 90, the covered electric wire 79 for the K charging bias was wound while being in direct contact with the surface of the front sheet metal 73. In the experiment of Experiment No. 2, the K charging bias covered wire 79 is held in the groove of the wire guide member 90 to be separated from the surface of the front sheet metal by 100 [mm]. That is, as the wire guide member 90, one having a height X of 100 [mm] between the groove bottom and the screw fixing portion bottom is used. In the experiment of Experiment No. 3, a wire guide member 90 having a height X between the groove bottom and the screw fixing portion bottom of 45 [mm] is used. In the experiment of Experiment No. 4, a wire guide member 90 having a height X between the groove bottom and the screw fixing portion bottom of 20 [mm] is used. In the experiment of Experiment No. 5, a wire guide member 90 having a height X of 15 [mm] between the groove bottom and the screw fixing portion bottom surface is used. In the experiment of Experiment No. 6, a wire guide member 90 having a height X of 10 [mm] between the groove bottom and the screw fixing portion bottom surface is used. Further, in the experiment of Experiment No. 7, two wire guide members 90 having a height X of 10 [mm] between the groove bottom and the screw fixing portion bottom surface are used. And the location which is not hold | maintained at these electric wire guide members 90 is provided in the covered electric wire 79, and these 2 locations are each made to contact the front sheet metal directly with the length of 60 [mm], and are wound around. In the experiment of Experiment No. 8, two wire guide members 90 having a height X of 20 [mm] between the groove bottom and the screw fixing portion bottom surface are used. And the location which is not hold | maintained at these electric wire guide members 90 is provided in the covered electric wire 79, and these 2 places are each made to contact the front sheet metal directly by the length of 50 [mm], and are wound around.

  When the entire region in the drive unit of the covered electric wire 79 is brought into contact with the front sheet metal 73 as in the experiment of Experiment No. 1, about 30 [%] of the total current output from the high voltage power unit 78 is reduced to the front sheet metal. As can be seen from FIG. When the covered wire 79 is not in direct contact with the front sheet metal 73 and the wire guide member 90 made of an insulating resin is interposed therebetween, the leakage current I3 decreases as the separation distance due to the increase increases. When the separation distance is in the range of 15 to 45 [mm], the ratio of the leakage current I3 can be kept at about 5 to 8 [%] (experiment numbers 3 to 5). When the separation distance is reduced to about 10 [mm], the ratio of the leakage current I3 is about 12 [%], and it is difficult to effectively suppress the current leakage (Experiment No. 6). Even if the wire guide member 90 is provided, if a part of the covered wire 79 is brought into contact with the front metal plate 73, the leakage current I3 increases (experiment numbers 7 to 8).

  For these reasons, the entire area of the covered wire 79 is separated from the front sheet metal 73, which is a metal member, by the wire guide member 90, and the distance is increased to some extent (the height of the wire guide member is increased to some extent). It was proved that current leakage from the covered wire 79 to the front sheet metal 73 can be effectively suppressed. The same experiment was performed for the development bias, the primary transfer bias, and the secondary transfer bias. However, by using the wire guide member 90 having a certain height, current leakage can be similarly suppressed. It was. In addition, the DC bias was tried, and the same result was obtained. Therefore, in this printer, it is possible to reliably apply design voltages to the developing roll, the charging roller, the primary transfer roller, and the secondary transfer roller while suppressing current leakage.

  Note that, instead of providing the wire guide member 90, even if the covered wire 79 is covered with an insulating covering material having a considerable thickness, the conductive wire in the covered wire 79 and the front sheet metal 73 are relatively large distances. It is possible to separate them with However, for example, in order to ensure an effective separation distance, it is necessary to use a covered electric wire 79 coated with an insulating covering material with a thickness of 15 [mm] or more, and such a covered electric wire 79 is not commercially available. . Therefore, it is necessary to make a custom-made wire with a considerable coating thickness as the covered wire 79, which leads to an increase in cost. Furthermore, the diameter of the covered wire 79 in which the periphery of the conducting wire is covered with a thickness of 15 [mm] or more is at least 30 [mm] or more. When such a thick covered electric wire 79 is used, it is difficult to reduce the size of the apparatus. By adopting a configuration in which the conductive wire is separated from the front sheet metal 73 by the wire guide member 90, such an increase in cost and difficulty in space saving can be avoided.

  FIG. 17 is an enlarged perspective view showing an electric wire guide member 90 as an electric wire holder. In the figure, an electric wire guide member 90 includes a main body portion 90b having a groove 90a extending in the surface direction of a front sheet metal (not shown) (73 in FIG. 13), a plurality of leg portions 90c protruding from the bottom surface thereof, And a plurality of claws 90d provided so as to be arranged at a predetermined pitch in the longitudinal direction of the portion 90b. A covered electric wire (not shown) is held in the groove 90a of the main body 90b. The plurality of leg portions 90c integrally formed with the main body portion 90b have a horizontal plane portion at the bottom thereof, and the back surface of the horizontal plane portion is brought into close contact with a front sheet metal (not shown). By interposing the leg portion 90c between the main body portion 90b and the front sheet metal, a large distance between the covered wire held in the groove 90a of the main body portion 90b and the front sheet metal is ensured. The plurality of claws 90d are cantilevered on one of the two walls on both sides of the groove so as to partially cover the upper end of the groove 90a. The claw 90d is also integrally formed with the main body 90a.

  So far, the printer for forming a color image by the process unit for each color has been described. However, the present invention can also be applied to an image forming apparatus having an image forming apparatus for forming only a single color image.

  As described above, in the printer according to the embodiment, the wire guide member 90 serving as the wire holding body is made of an insulating resin. Since the insulating resin is a material that is very easy to mold in a complicated shape, it can be manufactured at a relatively low cost. For this reason, even if a plurality of wire guide members 90 having various shapes are provided in accordance with the layout in the printer, an increase in cost due to this can be suppressed.

  In the printer according to the embodiment, the wire guide member 90 is provided with a groove 90a for holding the covered wire 79, and the covered wire 79 is wound around in the groove 90a. In such a configuration, the movement of the covered electric wire 79 in the sheet metal surface direction is restricted by rolling the covered electric wire 79 into the groove 90a. Accordingly, it is possible to avoid contact between the covered wire 79 and the front sheet metal 73 due to the covered wire 79 held by the wire guide member 90 being separated from the wire guide member 90 by the movement in the sheet metal surface direction due to vibration or impact. it can.

  In the printer according to the embodiment, the wire guide member 90 is provided with a plurality of claws 90d provided along the groove extending direction for preventing the covered wire 79 from being detached from the groove 90a. Thereby, it is possible to avoid contact between the covered wire 79 and the front metal plate 73 caused by detaching the covered wire 79 held in the groove 90a from the wire guide member 90 by the movement in the groove height direction due to vibration or impact. .

  In the printer according to the embodiment, the rear sheet metal 74 as a drive source holding body that holds the drive motor 75 as a drive source, the photosensitive member as the latent image carrier, and the charging device as the charging means. A charging roller, a developing roll of a developing unit as a developing means, and a front sheet metal 73 as a transmission mechanism holding body for holding a driving transmission mechanism 77 for transmission to a driving roller 47 of a transfer unit 40 as a transferring means are passed through a predetermined gap. And a drive unit 71 disposed opposite to each other. A drive power supply circuit for supplying power to the drive motor 75 and a drive wire 76 for guiding the power from the drive power supply circuit to the drive motor 75 are also provided. Then, the covered wire 79 is wound around the surface of the front sheet metal 73 which is a metal member and the transmission mechanism holding body via the wire guide member 90, and the driving wire is formed on the surface of the rear sheet metal 74 which is the driving source holding body. I'm scolding 76. In such a configuration, the covered electric wire 79 and the driving electric wire 76 are wound around on separate sheet metals arranged to face each other with a predetermined gap therebetween, thereby ensuring a certain distance between the two electric wires. Thereby, mixing of noise from the covered electric wire 79 to which a high voltage is applied to the driving electric wire 76 to which a relatively low voltage is applied can be suppressed, and instability of the rotational speed of the drive motor 75 due to noise can be suppressed.

  In the printer according to the embodiment, the charging device (for example, 5Y) as a charging unit uniformly charges the surface of the photoreceptor (for example, 3Y) by the discharge from the charging roller (for example, 6Y) as the charging member. The high voltage power unit 78 having a high voltage power supply circuit supplies a charging bias as a charging voltage as a high voltage to the charging roller. With such a configuration, it is possible to reliably uniformly charge the photosensitive member to a desired voltage by suppressing a drop in the charging current I1 due to current leakage from the covered wire 79 to the front sheet metal 73.

  In the printer according to the embodiment, the developing unit (for example, 7Y) as the developing unit develops the latent image with the developer carried on the surface of the developing roll (for example, 12Y) as the developing member, and the high-voltage power source A high voltage power unit 78 having a circuit supplies a developing bias as a developing voltage as a high voltage to the developing roll. With such a configuration, it is possible to suppress a decrease in development current due to current leakage from the covered wire 79 to the front sheet metal 73, and to reliably generate a desired development potential between the developing roll and the photosensitive member. As a result, the development quality can be stabilized.

  In the printer according to the embodiment, the transfer unit 40 serving as a transfer unit moves a toner image that forms a visible image of a photoreceptor (for example, 3Y) toward a primary transfer roller (for example, 45Y) that serves as a transfer member. A high-voltage power unit 78 that transfers to the intermediate transfer belt 41 as a body and has a high-voltage power supply circuit supplies a primary transfer bias as a transfer voltage to the primary transfer roller as a high voltage. In such a configuration, a primary transfer electric field having a desired strength is reliably formed between the photosensitive member and the primary transfer roller by suppressing a drop in the primary transfer current due to current leakage from the covered wire 79 to the front sheet metal 73. can do. As a result, the quality of the primary transfer toner image on the intermediate transfer belt 41 can be stabilized.

  In the printer according to the embodiment, the transfer unit 40 moves the primary transfer toner image transferred from the photosensitive member to the intermediate transfer belt 41 toward the secondary transfer roller 50 that is a transfer member, and the recording paper P that is a transfer member. The high voltage power unit 78 supplies a secondary transfer bias as a transfer voltage to the secondary transfer roller 50 as a high voltage. In such a configuration, a drop in the secondary transfer current due to current leakage from the covered electric wire 79 to the metal member wound around this is suppressed, and a desired strength is provided between the secondary transfer backup roller 46 and the secondary transfer roller 50. The secondary transfer electric field can be reliably formed. As a result, the quality of the secondary transfer toner image on the recording paper P can be stabilized.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 3 is an enlarged configuration diagram illustrating a process unit for Y of the printer. The perspective view which shows the process unit. The perspective view which shows the image development unit of the process unit. FIG. 2 is an enlarged configuration diagram illustrating a fixing device of the printer. FIG. 3 is a perspective view showing a toner cartridge for Y of the printer. FIG. 3 is a perspective view showing a cartridge connecting portion that is a part of the toner supply device of the printer. The perspective view which shows the suction pump for Y among the four suction pumps in the toner supply apparatus. FIG. 3 is a perspective view showing the toner replenishing device and its peripheral configuration. FIG. 3 is a plan view showing each process unit in the printer and its peripheral configuration from above. The perspective view which shows the drive unit of the printer. The enlarged plan view which shows the drive unit from upper direction. The expansion perspective view which shows the front sheet metal of the drive unit partially. The perspective view which shows the process unit for Y from the rear surface side. FIG. 2 is a perspective view showing a transfer unit of the printer from the rear side. FIG. 3 is a schematic diagram showing a circuit configuration mounted on a printer testing machine. The expansion perspective view which shows the electric wire guide member fixed to the front sheet metal.

Explanation of symbols

1Y, C, M, K: Process unit (part of image forming means)
2Y, C, M, K: Photosensitive unit (part of image forming means)
3Y, C, M, K: photoconductor (latent image carrier)
5Y: Charging device (charging means)
6Y: charging roller (charging member)
7Y, C, M, K: Developing unit (part of image forming means, developing means)
12Y: Developing roll (developing member)
40: Transfer unit (part of image forming means, transfer means)
41: Intermediate transfer belt (intermediate transfer member)
45Y, C, M, K: Primary transfer roller (transfer member)
50: Secondary transfer roller (transfer member)
71: Drive unit 73: Front sheet metal (metal member, transmission mechanism holder)
74: Rear sheet metal (drive source holder)
77: Drive transmission mechanism 75: Drive motor (drive source)
76: Driving wire 78: High voltage power unit (high voltage power circuit)
79: Covered wire 90: Wire guide member (wire holder)
90a: groove 90d: nail

Claims (9)

A latent image carrier for carrying a latent image, a charging means for uniformly charging the surface of the latent image carrier, a developing means for developing a latent image carried on the latent image carrier to obtain a visible image, and Transfer means for transferring a visible image on the latent image carrier to a transfer body;
At least one drive source for driving the latent image carrier, charging means, developing means and transfer means;
A high-voltage power supply circuit for generating a high voltage to be supplied to the imaging means;
A lead wire for guiding the high voltage from the high-voltage power supply circuit to the image forming means, and a covered electric wire comprising an insulating material covering the lead wire;
In an image forming apparatus comprising a metal member that holds a part of the covered electric wire,
An image in which an electric wire holder made of an insulating material for holding the part of the covered electric wire is provided, and the metal member is indirectly held by the metal part through the electric wire holder. Forming equipment. The image forming apparatus according to claim 1.
An image forming apparatus using an insulating resin as the wire holder. The image forming apparatus according to claim 1 or 2,
An image forming apparatus in which a wire provided with a groove for holding the covered wire is used as the wire holding body, and the covered wire is held in the groove. The image forming apparatus according to claim 3.
An image forming apparatus comprising: a plurality of claws provided along the groove extending direction for preventing the covered electric wires from being detached from the grooves. The image forming apparatus according to any one of claims 1 to 4,
A driving source holding body for holding the driving source; and a transmission mechanism holding body for holding a driving transmission mechanism for transmitting the driving force of the driving source to the latent image carrier, the charging unit, the developing unit, or the transferring unit. A drive unit disposed oppositely across a predetermined gap; a drive power supply circuit for supplying power to the drive source; and a drive wire for guiding power from the drive power supply circuit to the drive source. The covering electric wire is indirectly held on the surface of the transmission mechanism holding member as a member via the electric wire holding member, and the driving electric wire is held on the surface of the driving source holding member. Image forming apparatus. The image forming apparatus according to claim 1,
The charging means uniformly charges the surface of the latent image carrier by discharging from the charging member, and the high-voltage power supply circuit supplies a charging voltage to the charging member as the high voltage. An image forming apparatus, comprising: The image forming apparatus according to any one of claims 1 to 6,
The developing means develops the latent image with a developer carried on the surface of the developing member, and the high-voltage power supply circuit supplies a developing voltage to the developing member as the high voltage. An image forming apparatus. The image forming apparatus according to claim 1,
The transfer means moves the visible image on the latent image carrier toward the transfer member and transfers it to the transfer member, and the high-voltage power supply circuit applies the transfer voltage as the high voltage. An image forming apparatus which is supplied to a transfer member. The image forming apparatus according to any one of claims 1 to 8,
The transfer means moves the visible image transferred from the latent image carrier to the intermediate transfer member toward the transfer member and transfers it to the transfer member, and the high-voltage power supply circuit An image forming apparatus for supplying a transfer voltage as a voltage to the transfer member.

Images