JP4656096B2 - Developer supply apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a developer supply device that supplies a developer to a developer supply target by conveying the developer by an electric field, and an image forming apparatus including the developer supply device.

  2. Description of the Related Art Conventionally, there is a developer supply device that stores a developer for forming an image on a recording medium (for example, paper) and supplies the stored developer to a developer supply target (for example, a photosensitive drum). Are known.

  One of the developer supply apparatuses includes a cylindrical conveyance body that is disposed to face a developer supply target. A conveyance body has an electrode group which consists of a plurality of electrodes arranged at equal intervals in the peripheral direction. The developer supply device forms an electric field on the carrier by applying a traveling wave voltage to the electrode group. The charged developer among the developers supplied on the transport body is transported in one direction in the circumferential direction on the transport body by this electric field.

Further, the developer supply device is configured to form an electric field in a direction in which the charged developer is moved from the transport body to the developer supply target in a space between the transport body and the developer supply target. Each potential of the agent supply target is set. Therefore, when the developer reaches the space between the conveyance body and the developer supply target, the developer is moved toward the developer supply target by an electric field formed in the space (see, for example, Patent Document 1). ).
JP 2006-251104 A

By the way, it is thought that it is suitable to make this conveyance body as follows.
First, it has a cylindrical base material, a first pair of sides having the same length as the circumference of the outer peripheral surface of the base material, and a second pair of sides orthogonal to the first pair of sides. And a rectangular substrate formed on the substrate. A plurality of electrodes are disposed on the substrate. Next, the substrate is arranged so that the second pair of sides are parallel to the central axis of the base material, and the substrate is wound around the base material and fixed. In this way, a transport body is created.

  On the other hand, when manufacturing the substrate and the base material, manufacturing variations occur, so it is difficult to completely match the circumference of the outer peripheral surface of the base material with the length of the first pair of sides of the substrate. It is. As a result, relatively large irregularities are formed on the surface of the joint portion formed by the second pair of sides of the transport body. Thereby, the developer conveyed on the outer peripheral surface of the conveyance body is retained. As a result, there is a problem that the possibility that the amount of the developer supplied to the developer supply target is different from the planned amount increases.

  SUMMARY An advantage of some aspects of the invention is that it is possible to prevent the amount of developer supplied to a developer supply target from being different from a planned amount. Is to provide a simple developer supply apparatus.

In order to achieve such an object, the developer supply apparatus according to the present invention comprises:
A carrier having an electrode group composed of a plurality of electrodes;
A transport unit that forms an electric field that transports the developer in a predetermined transport direction along a transport surface that is a surface of the transport body by applying a traveling wave voltage to the electrode group;
And supplying the developer to a first region on the transport surface and supplying the developer transported in a second region on the transport surface to a developer supply target.

  The transport body is a flexible substrate on which the electrode group is disposed, and both end portions of the substrate including an upstream end portion in the transport direction and a downstream end portion in the transport direction are joint portions. And the joint is located upstream of the first region in the transport direction and downstream of the second region in the transport direction. It is arranged at the position.

  According to this, the joint portion is a position upstream of the first region where the developer is supplied to the transport body in the transport direction and from the transport body to a developer supply target (for example, a photosensitive drum). It is disposed at a position downstream of the second region to which the developer is supplied in the transport direction. Therefore, even if the developer being transported stays at the joint, the developer newly supplied to the first region reaches the second region smoothly, so that the development supplied to the developer supply target There is no shortage of agents. That is, it is possible to prevent the amount of the developer supplied to the developer supply target from being different from the planned amount.

  In addition, when no electrode is disposed at the upstream end or the downstream end in the substrate transport direction, the density of the electrode at the joint is lower than the other portions. Accordingly, the electric field formed in the joint portion for transporting the developer is weaker than the electric field formed in other portions. As a result, the developer conveyed on the outer peripheral surface of the conveyance body is retained at the joint.

  Therefore, as in the above-described configuration, if the joint portion is disposed at a position upstream of the first region in the transport direction and downstream of the second region in the transport direction, the developer being transported Even if the toner stays at the joint portion, it is possible to prevent the amount of the developer supplied to the developer supply target from being different from the planned amount.

  In this case, it is preferable that the shape of the substrate before being curved is a square shape.

  In this case, it is preferable that the shape of the substrate before being bent is a rectangular shape.

  In this case, the joint portion is formed by overlapping the downstream end portion in the transport direction of the both end portions on the outer peripheral surface of the upstream end portion in the transport direction of the both end portions. Is preferable.

  When the upstream end (upstream end) in the substrate transport direction is overlapped with the downstream end (downstream end) in the substrate transport direction, it is configured by the upstream end at the joint. The developer cannot pass through the joint unless the step is climbed. That is, the developer conveyance is hindered at the joint. Accordingly, as described above, the downstream end is overlapped on the upstream end, so that the developer can pass through the joint portion without climbing the step, so that the upstream end is on the downstream end. Therefore, the developer can be transported more smoothly than the case where the toners are stacked on each other.

In addition, another developer supply apparatus according to the present invention includes:
A flexible substrate on which a first electrode group consisting of a plurality of electrodes is disposed, and both ends of the substrate including an upstream end in a predetermined transport direction and a downstream end in the transport direction A first carrier having a substrate curved to form a seam portion;
By applying a traveling wave voltage to the first electrode group, a first electric field for transporting the developer in the transport direction is formed along the first transport surface which is the surface of the first transport body. 1 transport means;
A second electrode group comprising a plurality of electrodes is disposed, and a second electrode group is disposed so as to face a seam portion arrangement region including the seam portion of the first transport surface with a predetermined distance therebetween. A carrier of
By applying a traveling wave voltage to the second electrode group, the developer is applied in the transport direction along the second transport surface, which is the surface of the second transport body on the first transport body side. A second transfer means for forming an electric field to be transferred;
And supplying the developer to a first region on the first transport surface and supplying the developer transported in a second region on the first transport surface to a developer supply target The developer supply device.

  According to this, the second transport body is disposed so as to face the seam portion arrangement region including the seam portion of the first transport surface, and the developer on the second transport surface is moved in the transport direction. An electric field to be conveyed is formed. As a result, the strength of the electric field formed by the second transport body increases as the distance from the first transport surface increases. Therefore, even when the developer moves away from the first transport surface, the developer is transported in the transport direction. It is possible to prevent the force (conveying force) to be conveyed to excessively small.

  As a result, the developer leaving the first transport surface for certain reasons, such as scattering due to the collision between the developers and an electric field for keeping the developer away from the first transport surface, is surely near the joint. Since the toner can be transported, the amount of the developer retained at the joint can be reduced. Accordingly, since the developer can be smoothly conveyed, it is possible to prevent the amount of the developer supplied to the developer supply target from being different from the planned amount.

  The present invention has been made in order to cope with the same problem as the above invention (excess or deficiency of developer supplied to the developer supply target due to retention of developer at the joint portion). It has a special technical feature (the second conveyance body is disposed so as to face the seam portion arrangement region including the seam portion) that clearly shows the contribution to the related art. Therefore, the present invention corresponds to a special technical feature of the present invention (the seam portion is disposed at a position upstream of the first region and downstream of the second region). It can be said that the invention has special technical features.

  In this case, the seam portion is a direction along the normal line of the first conveyance surface and is a normal outward direction from the first conveyance surface toward the outside of the first conveyance body. Is preferably disposed at a position (on the first transport surface) having a vertically downward component.

  At a position where the normal outward direction has a vertically downward component (on the first transport surface), the developer on the first transport surface is easily separated from the first transport surface by gravity. Therefore, according to the above configuration, the amount of the developer conveyed in the conveyance direction in the state of being separated from the first conveyance surface in the vicinity of the joint portion is determined as the position where the normal outward direction has a component in the vertical upward direction. This can be increased as compared with the case where the seam portion is disposed on the surface. As a result, the amount of developer retained at the joint can be reduced. That is, since the developer can be smoothly conveyed, it is possible to prevent the amount of the developer supplied to the developer supply target from being different from the planned amount.

Meanwhile, another developer supply apparatus according to the present invention is
A carrier having an electrode group composed of a plurality of electrodes;
A transport unit that forms an electric field that transports the developer in a predetermined transport direction along a transport surface that is a surface of the transport body by applying a traveling wave voltage to the electrode group;
A developer supply device that supplies the developer to a first region on the transport surface and supplies the developer transported in a second region on the transport surface to a developer supply target. is there.

  The transport body is a flexible substrate on which the electrode group is disposed, and both end portions of the substrate including an upstream end portion in the transport direction and a downstream end portion in the transport direction are joint portions. And a endless coating layer that forms the transport surface by seamlessly covering the curved substrate.

  According to this, the unevenness | corrugation of the conveyance surface in a joint part can be made small or eliminated compared with the case where a conveyance body is not provided with an endless coating layer. Accordingly, since the developer can be smoothly conveyed, it is possible to prevent the amount of the developer supplied to the developer supply target from being different from the planned amount.

  The present invention has been made in order to cope with the same problem as the above invention (excess or deficiency of developer supplied to the developer supply target due to retention of developer at the joint portion). It has special technical features that clearly demonstrate its contribution to the prior art (the carrier comprises an endless coating layer that constitutes the outermost part of the carrier and has no seams). Therefore, the present invention corresponds to a special technical feature of the present invention (the seam portion is disposed at a position upstream of the first region and downstream of the second region). It can be said that the invention has special technical features.

An image forming apparatus according to the present invention includes any one of the developer supply devices described above.
It is preferable that the image forming apparatus includes an image forming unit that forms an image on a recording medium with the developer supplied from the developer supply device.

  According to this, since the amount of the developer supplied from the developer supply device to the developer supply target can be brought close to the planned amount, the quality of the image formed on the recording medium can be improved.

<Configuration>
Hereinafter, an image forming apparatus including a developer supply apparatus according to an embodiment of the present invention will be described with reference to the drawings. This image forming apparatus is a laser printer (image forming apparatus) 10 that performs monochrome printing, whose schematic cross section is shown in FIG. Hereinafter, the description will be continued using a right-handed orthogonal coordinate system including the X-axis, the Y-axis, and the Z-axis, in which the Y-axis negative direction coincides with the vertically downward direction (that is, the direction in which gravity works). .

  As shown in FIG. 1, the laser printer 10 includes a pair of registration rollers 21 and 22, a photosensitive drum 31 as a latent image carrier, a developer supply device 32, a charger 41, a scanner unit 42, and the like. The transfer roller 51 is included. Each of the photosensitive drum 31, the charger 41, the scanner unit 42, and the transfer roller 51 constitutes a part of an image forming unit.

  The laser printer 10 accommodates sheets P as recording media stacked in a sheet feeding tray (not shown). The laser printer 10 is configured to send the stored paper P one by one toward the registration rollers 21 and 22. The registration rollers 21 and 22 are configured to send out the fed paper P between the photosensitive drum 31 and the transfer roller 51 at a predetermined timing.

  As shown in part of FIG. 2, the photosensitive drum 31 has a cylindrical drum body 31a having a central axis LC parallel to the Z axis, and an outer peripheral surface (surface on the outer diameter side) of the drum body 31a. And formed photosensitive layer 31b. The drum body 31a is made of a conductive material (in this example, metal), and is set so that its potential becomes a predetermined potential. In this example, the drum main body 31a is grounded so that the potential becomes 0 [V]. A predetermined voltage may be applied (biased) to the drum body 31a.

  The photosensitive layer 31b is made of a positively charged photoconductor. That is, when the photosensitive layer 31b is exposed in a state where the positive polarity is substantially uniformly charged (positively charged), the exposed portion is exposed and the absolute value (size) of the amount of charge of the exposed portion is exposed. ) Has been reduced. The photosensitive drum 31 rotates in the counterclockwise direction in FIGS. 1 and 2. The outer peripheral surface of the photosensitive layer 31b is a surface also referred to as a latent image forming surface LS in this specification.

  As shown in an enlarged view in FIG. 2, the developer supply device 32 includes a top surface 32a and a bottom surface 32b that are planes orthogonal to the Y axis, two side surfaces (not shown) that are planes orthogonal to the Z axis, and X It has a substantially rectangular parallelepiped shape having a front surface 32c and a back surface 32d, which are planes orthogonal to the axis. The length of the developer supply device 32 in the Z-axis direction is substantially the same as the length of the photosensitive drum 31 in the Z-axis direction.

  The front surface 32c is disposed so as to face the latent image forming surface LS with a slight distance from the latent image forming surface LS. The front surface 32c is formed with a developer supply hole 32c1 that is open in a rectangular shape having a long side and a short side. The long side of the developer supply hole 32c1 is parallel to the Z axis and has substantially the same length as the length of the photosensitive drum 31 in the Z axis direction.

A developer storage space SP having a substantially rectangular parallelepiped shape is formed inside the developer supply device 32. The developer accommodation space SP communicates with the outside of the developer supply device 32 through the developer supply hole 32c1.
In the developer storage space SP, the first transport body 33a, the second transport body 33b, the first auxiliary transport body 33c, the second auxiliary transport body 33d, the third auxiliary transport body 33e, and the fourth auxiliary transport body A carrier 33f is accommodated.

  Note that the set of the first transport body, the second transport body, and the developer supply target included in the developer supply device according to the present invention includes the first transport body 33a as the first transport body, and the second transport body. A set of a third auxiliary transport body 33e as a body and a second transport body 33b as a developer supply target, a second transport body 33b as a first transport body, and a second as a second transport body The auxiliary conveyance body 33d and the photosensitive drum 31 as a developer supply target are both included.

  The first transport body 33a has a hollow cylindrical shape. The first transport body 33a is disposed substantially at the center of the developer accommodating space SP. The first transport body 33a is arranged such that the central axis TC1 is parallel to the Z axis. Each of both end portions in the Z-axis direction of the first transport body 33a is fixed to an inner wall surface that forms the developer accommodating space SP.

  The first transport body 33a includes a base material layer 33a1, a substrate layer 33a2, and an endless coating layer 33a3, as shown in FIG. 3A showing only the first transport body 33a in an enlarged manner. Each of the base material layer 33a1, the substrate layer 33a2, and the endless coating layer 33a3 has a predetermined thickness.

The base material layer 33a1 constitutes the innermost portion in the radial direction of the first transport body 33a. The base material layer 33a1 is a rigid body.
The substrate layer 33a2 is adjacent to the base material layer 33a1 in the radial direction of the first transport body 33a and constitutes a portion on the outer diameter side of the base material layer 33a1.

Here, a method for forming the substrate layer 33a2 will be described.
First, as shown in FIG. 4A, a base material layer 33a1 and a flexible substrate (in this example, a flexible printed circuit board) PS are prepared.

  The substrate PS has a pair of parallel sides (first pair of sides) having the same length as the outer periphery of the base material layer 33a1 in a cross section obtained by cutting the base material layer 33a1 by a plane orthogonal to the central axis TC1 of the base material layer 33a1. Side) and a pair of mutually parallel sides (second pair of sides) EG1 and EG2 having the same length as the length of the base material layer 33a1 in the central axis direction. In addition, since all four corners are equal quadrangles, the rectangle includes a square that is a quadrangle in which all four corners are equal and all four sides are equal in length.

  In this specification, the direction parallel to the first pair of sides and moving while traversing the substrate PS from the side EG1 to the side EG2 is referred to as a transport direction TD. Accordingly, the end portion including the side EG1 is also referred to as an upstream end portion (upstream end portion) in the transport direction of the substrate PS, and the end portion including the side EG2 is the downstream end portion in the transport direction of the substrate PS. Also called an end (downstream end).

As shown in FIG. 5 showing an enlarged cross section of the substrate PS obtained by cutting the substrate PS shown in FIG. 4A along a plane orthogonal to the sides EG1 and EG2, the substrate PS includes a base film BF and a plurality of substrates PS. An electrode EL and an interelectrode insulator IS are provided. Note that the plurality of electrodes EL constitutes an electrode group (first electrode group).
The base film BF is made of an insulating resin (in this example, polyimide).

  Each of the plurality of electrodes EL is a rectangular parallelepiped metal (copper in this example) extending in a direction parallel to the second pair of sides EG1 and EG2. Each of the plurality of electrodes EL has the same shape. Each of the plurality of electrodes EL is fixed on the base film BF. The plurality of electrodes EL are arranged at equal intervals in the transport direction TD (so that the distance between the two adjacent electrodes EL and EL is constant).

  The interelectrode insulator IS is made of an insulating material (in this example, an insulating resin). The interelectrode insulator IS is disposed between two adjacent electrodes EL and EL. The surface of the interelectrode insulator IS opposite to the surface in contact with the base film BF forms the same surface as the surface of the electrode EL opposite to the surface in contact with the base film BF. With such a configuration, the interelectrode insulator IS prevents two adjacent electrodes EL from being short-circuited. In this example, the electrode pitch length DP, which is the length in the transport direction TD, of a set of components including one electrode EL and one interelectrode insulator IS adjacent to the electrode EL is 0.2 mm.

  Then, as shown in FIG. 4A, the substrate PS is exposed on the side where the second pair of sides EG1, EG2 is parallel to the central axis TC1 of the base material layer 33a1 and the base film BF is exposed. Is arranged so that the surface of the substrate faces the outer peripheral surface of the base material layer 33a1. Next, the base film BF is fixed to the outer peripheral surface of the base material layer 33a1 with an adhesive. Specifically, first, an end including the side EG1 of the base film BF is fixed to the outer peripheral surface of the base material layer 33a1. Then, the base film BF is sequentially fixed from the side EG1 to the side EG2 while the substrate PS is curved in the direction of the arrow A1 so that the substrate PS is along the outer peripheral surface of the base material layer 33a1.

  In this way, as shown in FIG. 4B, the substrate layer 33a2 includes the upstream end (end including the side EG1) and the downstream end (end including the side EG2). Both ends are formed by bending the substrate PS so as to form the joint portion JT1.

  By the way, when the length of the first pair of sides of the substrate PS is shorter than the outer periphery of the base material layer 33a1, as shown in FIG. 6A, the upstream end and the downstream end. Are separated from each other in the direction along the outer peripheral surface of the base material layer 33a1 (conveying direction TD). That is, a concave portion is formed at the joint portion JT1.

  On the other hand, when the length of the first pair of sides of the substrate PS is longer than the outer periphery of the base material layer 33a1, the downstream end is the downstream end as shown in FIG. Is overlapped on the outer peripheral surface OTS of the upstream end so that the inner peripheral surface INS of the portion and the outer peripheral surface OTS of the upstream end are in contact with each other. That is, the raised portion is formed at the joint portion JT1.

  Further, even if the length of the first pair of sides of the substrate PS is the same as the outer circumference of the base material layer 33a1, the thickness at the upstream end of the substrate PS and the thickness at the downstream end of the substrate PS Are different, a step is formed at the joint JT1 as shown in FIG.

  As described above, when the shapes of the substrate PS and the base material layer 33a1 are different from the planned shapes (shapes as designed), relatively large unevenness is formed in the joint portion JT1.

Referring to FIG. 3A again, the endless coating layer 33a3 constitutes the outermost portion in the radial direction of the first transport body 33a.
Here, a method for forming the endless coating layer 33a3 will be described.
First, as shown in FIG. 7A, a pre-covering transport body PT in which a substrate layer 33a2 is formed on a base material layer 33a1 and a heat-shrinkable tube TT are prepared.

  This heat-shrinkable tube TT has a hollow cylindrical shape without a seam. The heat-shrinkable tube TT is made of a material that contracts greatly and plastically deforms once heated to a predetermined shrinkage temperature, and that positively charges the developer T by friction with the developer T. In this example, the heat shrinkable tube TT is made of a material mainly composed of Teflon (registered trademark). The heat-shrinkable tube TT is made of tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE), or tetrafluoroethylene. -You may consist of materials which have fluororesins other than Teflon (trademark), such as ethylene copolymer (ETFE), as a main component. The heat-shrinkable tube TT has an inner diameter that is slightly larger than the outer diameter of the pre-coating transport body PT. The length of the heat-shrinkable tube TT in the central axis direction is substantially the same as the length of the pre-covering transport body PT in the central axis direction.

  Then, the heat-shrinkable tube TT is disposed so as to cover the outer peripheral surface of the pre-covering transport body PT (that is, the pre-covering transport body PT is inserted into the heat-shrinkable tube TT), and the disposed heat-shrinkable tube TT is shrunk as described above. Heat to temperature. As a result, the heat-shrinkable tube TT is shrunk and the heat-shrinkable tube TT is fixed to the outer peripheral surface of the pre-coating transport body PT. In this way, as shown in FIG. 7B, the endless coating layer 33a3 is formed. Therefore, the endless coating layer 33a3 seamlessly covers the outer surface (outer peripheral surface) in the radial direction of the substrate layer 33a2 (curved substrate PS). The outer peripheral surface of the endless coating layer 33a3 is also referred to as a transport surface TS.

In the present embodiment, the endless coating layer 33a3 is formed by contracting the heat-shrinkable tube TT. However, the transport before coating is made of a material that is greatly expanded and plastically deformed at a predetermined expansion temperature. It may be formed by fixing the tube to the outer peripheral surface of the pre-coating transport body by preparing the body and expanding the pre-coating transport body. In addition, the endless coating layer 33a3 expands the transport body before coating by preparing a tube and a transport body before coating and making the pressure of the internal space of the transport body before coating higher than the pressure of the external space of the transport body before coating. As a result, it may be formed by fixing the tube to the outer peripheral surface of the pre-coating transport body.
Further, the endless coating layer 33a3 may be formed by forming a film (for example, applying a paint) on the outer peripheral surface of the pre-coating transport body PT.

  As shown in FIG. 2, the joint portion JT1 of the first transport body 33a is arranged at a position in the plane PL1 and on the Y axis positive direction side. The plane PL1 is a plane orthogonal to the X axis and passes through the central axis TC1 of the first transport body 33a.

  The 2nd conveyance body 33b consists of the base material layer 33b1, the board | substrate layer 33b2, and the endless coating layer 33b3, as shown to (B) of FIG. The second transport body 33b is formed in the same manner as the first transport body 33a.

  As shown in FIG. 2, the second transport body 33 b is disposed between the first transport body 33 a and the photosensitive drum 31 with a predetermined distance from each of the first transport body 33 a and the photosensitive drum 31. Has been. The second transport body 33b is arranged so that the central axis TC2 is parallel to the Z axis. Each of both end portions in the Z-axis direction of the second transport body 33b is fixed to an inner wall surface that forms the developer accommodating space SP.

  The joint portion JT2, which is a portion where the second pair of sides EG1 and EG2 of the substrate PS in the second transport body 33b are connected to each other, is a position in the plane PL2 and a position on the Y axis negative direction side. Has been placed. The plane PL2 is a plane orthogonal to the X axis and passes through the central axis TC2 of the second transport body 33b. That is, the seam portion JT2 has a normal outward direction that is a direction along the normal line of the transport surface TS of the second transport body 33b and that extends from the transport surface TS to the outside of the second transport body 33b. It is arranged at a position having a component in the vertical downward direction (Y-axis negative direction).

  The first auxiliary transport body 33c is disposed on the inner wall surface SPa on the Y axis negative direction side, which is orthogonal to the Y axis, among the inner wall surfaces forming the developer accommodating space SP. As shown in FIG. 8, the first auxiliary transport body 33 c includes a substrate having the same configuration as the substrate PS and a coating layer CF. The coating layer CF is made of a material mainly composed of Teflon (registered trademark). The covering layer CF is formed on the exposed surface of the substrate electrode EL and the interelectrode insulator IS. The first auxiliary transport body 33c is fixed to the inner wall surface SPa so that each electrode EL extends in a direction parallel to the Z axis and the base film BF is in contact with the inner wall surface SPa.

  As shown in FIG. 2, the end on the X-axis negative direction side of the first auxiliary transport body 33c is located in the vicinity of the end on the X-axis negative direction side of the inner wall surface SPa. The end on the X axis positive direction side of the first auxiliary transport body 33c is located in the plane PL3. The plane PL3 is a plane orthogonal to the X axis, and is a plane passing through an intermediate position between the center axis TC1 of the first transport body 33a and the center axis TC2 of the second transport body 33b.

  Of the inner wall surface SPa, a portion between the plane PL1 and the plane PL3 has a circular arc centered on the central axis TC1 on the inner wall surface SPa in a cross section obtained by cutting the developer supply device 32 by a plane orthogonal to the Z axis. Curved to draw. That is, the portion of the first auxiliary transport body 33c between the plane PL1 and the plane PL3 and the outer peripheral surface of the first transport body 33a face each other with a certain distance.

  In the developer accommodating space SP, the space on the negative side in the X-axis direction relative to the first transport body 33a is a fine particulate dry developer and a black developer (in this example, a non-component mainly composed of polyester). A magnetic one-component polymerized toner) T is accommodated. That is, the developer T is deposited on a portion of the first auxiliary transport body 33c on the X axis negative direction side with respect to the plane PL1.

  The second auxiliary transport body 33d is disposed on the inner wall surface SPa. The second auxiliary transport body 33d has the same configuration as the first auxiliary transport body 33c. Each electrode EL provided on the second auxiliary transport body 33d constitutes a second electrode group.

  The second auxiliary transport body 33d is disposed adjacent to the first auxiliary transport body 33c and closer to the X-axis positive direction side than the first auxiliary transport body 33c. The end on the X axis positive direction side of the second auxiliary transport body 33d is located in the vicinity of the end on the X axis positive direction side of the inner wall surface SPa.

  A portion of the inner wall surface SPa on the X axis positive direction side with respect to the plane PL3 (a portion where the second auxiliary transport body 33d is fixed) is a cross section in which the developer supply device 32 is cut by a plane orthogonal to the Z axis. Is curved so as to draw an arc centered on the central axis TC2. That is, as shown in FIG. 9, the second auxiliary transport body 33d and the joint portion arrangement area AJ2 including the joint portion JT2 on the outer peripheral surface of the second transport body 33b are opposed to each other with a certain distance. is doing.

  As shown in FIG. 2, the third auxiliary transport body 33e is disposed on the inner wall surface SPb perpendicular to the Y axis and on the Y axis positive direction side among the inner wall surfaces forming the developer containing space SP. Yes. The third auxiliary transport body 33e has the same configuration as the first auxiliary transport body 33c.

  The end on the X-axis negative direction side of the third auxiliary transport body 33e is located slightly on the X-axis negative direction side with respect to the plane PL1. The end of the third auxiliary transport body 33e on the X axis positive direction side is located in the plane PL3. A portion of the inner wall surface SPb between the plane PL1 and the plane PL3 has an arc whose center surface TC1 is the center of the inner wall surface SPb in a cross section obtained by cutting the developer supply device 32 by a plane orthogonal to the Z axis. Curved to draw. That is, the third auxiliary transport body 33e and the joint portion arrangement area AJ1 including the joint portion JT1 on the outer peripheral surface of the first transport body 33a are opposed to each other with a certain distance (see FIG. 9). .)

  The fourth auxiliary transport body 33f is disposed on the inner wall surface SPb. The fourth auxiliary transport body 33f has the same configuration as the first auxiliary transport body 33c.

  The fourth auxiliary transport body 33f is disposed adjacent to the third auxiliary transport body 33e and closer to the X-axis positive direction side than the third auxiliary transport body 33e. The end on the X-axis positive direction side of the fourth auxiliary transport body 33f is located in the vicinity of the end on the X-axis positive direction side of the inner wall surface SPb.

  A portion of the inner wall surface SPb on the X axis positive direction side with respect to the plane PL3 (a portion where the fourth auxiliary transport body 33f is fixed) cuts the developer supply device 32 by a plane orthogonal to the Z axis. The inner wall surface SPb in the cross section is curved so as to draw an arc centered on the central axis TC2. That is, the fourth auxiliary transport body 33f and the outer peripheral surface of the second transport body 33b face each other with a certain distance.

  Further, the laser printer 10 includes first power supply circuits V1a to V1d (not shown) and second power supply circuits V2a to V2d (not shown). The first power supply circuits V1a to V1d are connected to the first carrier 33a, the first auxiliary carrier 33c, and the third auxiliary carrier 33e, respectively.

  More specifically, any one of the first power supply circuits V1a to V1d is repeatedly connected in this order to each electrode EL of the first transport body 33a in the counterclockwise direction (transport direction TD) in FIG. ing. The first power supply circuits V1a to V1d connected to the respective electrodes EL of the first transport body 33a constitute transport means (first transport means).

  Any one of the first power supply circuits V1a to V1d is repeatedly connected in this order to each electrode EL of the first auxiliary transport body 33c in the positive X-axis direction. Any one of the first power supply circuits V1a to V1d is repeatedly connected in this order to each electrode EL of the third auxiliary transport body 33e in the negative X-axis direction. The first power supply circuits V1a to V1d connected to the respective electrodes EL of the third auxiliary transport body 33e constitute a second transport means.

Further, the second power supply circuits V2a to V2d are connected to the second transport body 33b, the second auxiliary transport body 33d, and the fourth auxiliary transport body 33f, respectively.
More specifically, any one of the second power supply circuits V2a to V2d is repeatedly connected in this order to each electrode EL of the second transport body 33b in the clockwise direction (transport direction TD) in FIG. Yes. The second power supply circuits V2a to V2d connected to the respective electrodes EL of the second transport body 33b constitute transport means (first transport means).

  Any one of the second power supply circuits V2a to V2d is repeatedly connected in this order to each electrode EL of the second auxiliary transport body 33d in the negative X-axis direction. The second power supply circuits V2a to V2d connected to the respective electrodes EL of the second auxiliary transport body 33d constitute a second transport means. Any one of the second power supply circuits V2a to V2d is repeatedly connected in this order to each electrode EL of the fourth auxiliary transport body 33f in the positive direction of the X-axis.

  Hereinafter, in this specification, for convenience of explanation, the electrode EL to which the first power supply circuit V1a or the second power supply circuit V2a is connected is referred to as an electrode ELa, and the first power supply circuit V1b or the second power supply circuit V2b is connected to it. The electrode EL is called an electrode ELb, the electrode EL to which the first power supply circuit V1c or the second power supply circuit V2c is connected is called an electrode ELc, and the electrode EL to which the first power supply circuit V1d or the second power supply circuit V2d is connected. May be referred to as electrode ELd.

  Referring to FIG. 1 again, the charger 41 is disposed so as to face the latent image forming surface LS. The charger 41 is connected to a bias circuit (not shown), and applies a bias to positively charge the latent image forming surface LS uniformly (in this example, a scorotron type charger). ).

  The scanner unit 42 includes a laser light emitting unit (not shown), and the laser light emitting unit generates a laser beam LB based on image data. The scanner unit 42 applies the generated laser beam LB to a position on the latent image forming surface LS and downstream of the charger 41 in the rotation direction of the photosensitive drum 31 (counterclockwise direction in FIG. 1). By forming an image at a position upstream of the developer supply device 32, the photosensitive layer 31b of the photosensitive drum 31 is exposed. Further, the scanner unit 42 moves (scans) the position at which the laser beam LB is formed on the latent image forming surface LS at a constant speed in a predetermined scanning direction substantially parallel to the Z axis. Yes.

  The transfer roller 51 rotates in the clockwise direction in FIG. The peripheral surface of the transfer roller 51 is disposed so as to contact the latent image forming surface LS of the photosensitive drum 31. The transfer roller 51 is connected to a bias circuit (not shown), and a latent image is formed in a state where the sheet P is sandwiched between the peripheral surface of the transfer roller 51 and the latent image forming surface LS by applying a bias. The developer T adhering to the formation surface LS is transferred onto the surface of the paper P.

  Further, the laser printer 10 includes a fixing unit (not shown), a paper discharge unit, and a control unit. Each of the fixing unit, the paper discharge unit, and the control unit constitutes a part of the image forming unit.

  The fixing unit fixes the developer T on the paper P by applying pressure while heating the paper P on which the developer T has been transferred. The paper discharge unit includes a paper discharge tray, and conveys the paper P that has passed through the fixing unit toward the paper discharge tray, and holds the conveyed paper P in the paper discharge tray.

  The control unit is electrically connected to various lasers, actuators, sensors, and other laser light emitting units, various bias circuits, and various power supply circuits provided in the scanner unit 42 for driving the movable units of the laser printer 10. Connected to each other, an instruction signal is sent to these at a predetermined timing.

<Operation>
Next, the operation of the laser printer 10 configured as described above will be described from the time when the user sends a print instruction signal including image data representing an image that the user wants to form to the laser printer 10.
When the control unit receives the print instruction signal, the control unit controls the photosensitive drum 31 and the transfer roller 51 to be in a rotating state (rotating state).

  In addition, the control unit controls the charger 41 to a state where a predetermined charging bias is applied (bias application state). As a result, the portion of the latent image forming surface LS (the peripheral surface of the photosensitive drum 31) that faces the charger 41 is charged positively (positively charged).

  As the photosensitive drum 31 rotates, the portion of the latent image forming surface LS downstream of the charger 41 in the rotational direction of the photosensitive drum 31 (counterclockwise in FIG. 1) is uniformly. Positively charged. That is, the potential of the latent image forming surface LS is a predetermined positive reference potential (in this example, +1000 [V]) at all positions in the same portion. In addition, the control unit controls the transfer roller 51 to a state where a predetermined transfer bias is applied (bias application state).

  Further, the control unit generates power in each of the first power supply circuits V1a to V1d by supplying power to each of the first power supply circuits V1a to V1d. As shown in FIG. 10, this voltage has a predetermined amplitude (250 [V] in this example) and a constant positive voltage (+600 [V] in this example) as an average voltage. It is a rectangular wave voltage with a period (4 ms in this example). Here, the waveforms of the voltages generated by the first power supply circuits V1a to V1d are different in phase by 90 °. That is, the phase of the voltage generated by each of the first power supply circuits V1a to V1d is delayed by 90 ° in this order.

  Thus, for example, at time t1 in FIG. 10, the potentials of the electrodes ELa and ELd (+350 [V]) are lower than the potentials of the electrodes ELb and ELc (+850 [V]).

  Therefore, as shown in FIG. 11A, which represents the time change of the electric field formed in the vicinity of the portion on the X axis negative direction side of the plane PL1 in the first auxiliary transport body 33c. A space (hereinafter simply referred to as “electrode ELa”) on the covering layer CF between a plane PLa orthogonal to the axis and passing through the electrode ELa and a plane PLb orthogonal to the X axis and passing through the electrode ELb. In the first auxiliary transport body 33c between the electrode ELb and the electrode ELb. The same applies to other spaces.) The electric field EF1 in the negative X-axis direction is mainly formed. As a result, the positively charged developer T located in this space is moved in the negative direction of the X axis in response to the electrostatic force generated by the electric field EF1.

Further, in the space on the first auxiliary transport body 33c between the electrode ELb and the electrode ELc, an electric field EF2 mainly in the Y-axis positive direction is formed. As a result, the positively charged developer T located in this space is moved in the positive direction of the Y axis under the electrostatic force generated by the electric field EF2.
Furthermore, in the space on the first auxiliary transport body 33c between the electrode ELc and the electrode ELd, an electric field EF3 mainly in the X-axis positive direction is formed. As a result, the positively charged developer T located in this space is moved in the positive direction of the X axis in response to the electrostatic force generated by the electric field EF3.
In addition, in the space on the first auxiliary transport body 33c between the electrode ELd and the electrode ELa, an electric field EF4 in the negative Y-axis direction is mainly formed. As a result, the positively charged developer T located in this space is moved in the negative direction of the Y axis in response to the electrostatic force generated by the electric field EF4.

  As described above, at the time point t1, the developer T is collected in the space on the first auxiliary transport body 33c between the electrode ELd and the electrode ELa and in the vicinity of the covering layer CF.

Similarly, at a time point t2 (see FIG. 10) after a quarter cycle has elapsed from the time point t1, the potential of the electrode ELa and the electrode ELb (+350 [V]) is changed to the potential of the electrode ELc and the electrode ELd (+850 [+ [ V]), the positively charged developer T is collected in the space on the first auxiliary transport body 33c between the electrode ELa and the electrode ELb as shown in FIG. 11B. It is done.
In addition, at a time point t3 (see FIG. 10) after a quarter cycle has elapsed from the time point t2, the potentials of the electrodes ELb and ELc (+350 [V]) are the potentials of the electrodes ELd and ELa (+850 [V]). ]), The positively charged developer T is collected in the space on the first auxiliary transport body 33c between the electrode ELb and the electrode ELc, as shown in FIG. 11C. .

  As described above, the positively charged developer T passes through the transport surface TS, which is the surface of the first auxiliary transport body 33c on the Y axis positive direction side, and the time elapses by a quarter period in the X axis positive direction. Each time it is moved, it is moved by a distance equal to the electrode pitch length DP.

  In this way, the developer T positively charged by friction with the transport surface TS which is the surface on the Y axis positive direction side of the first auxiliary transport body 33c or friction between the developers T is transferred to the transport surface TS. The first auxiliary transport body 33c is transported toward the end on the X axis positive direction side.

  That is, the voltage (traveling wave voltage) generated in the first power supply circuits V1a to V1d is applied to each electrode EL of the first auxiliary transport body 33c, so that the developer T is X along the transport surface TS. An electric field to be conveyed in the axial positive direction (conveying direction TD) is formed.

  On the other hand, the first transport body 33a is also connected to the first power supply circuits V1a to V1d in the same manner as the first auxiliary transport body 33c. Accordingly, the voltages (traveling wave voltages) generated in the first power supply circuits V1a to V1d are applied to the respective electrodes EL of the first transport body 33a, whereby the outer peripheral surface (transport surface TS) of the first transport body 33a is applied. 2 forms an electric field for transporting the positively charged developer T in the counterclockwise direction (transport direction TD) in FIG. 2 along the transport surface TS. In the present specification, the transport surface TS of the first transport body 33a is also referred to as a first transport surface.

As a result, as shown in FIG. 9, the developer T reaches the area AR1 in the transport surface TS of the first transport body 33a by being transported on the first auxiliary transport body 33c. In the present specification, it can be said that the area AR1 is a first area where the developer T is newly supplied to the transport surface TS of the first transport body 33a. The first area AR1 is an area on the conveyance surface TS of the first conveyance body 33a and is an area other than the joint portion arrangement area AJ1.
Then, the developer T that has reached the area AR1 is transported in the counterclockwise direction (transport direction TD) in FIGS. 2 and 9 along the transport surface TS of the first transport body 33a.

  Further, the control unit supplies power to each of the second power supply circuits V2a to V2d, thereby generating a voltage similar to the voltage generated in the first power supply circuits V1a to V1d and generated in the first power supply circuits V1a to V1d. A voltage having an average voltage lower than the generated voltage is generated in each of the second power supply circuits V2a to V2d. In this example, the average voltage is +400 [V].

  A voltage (traveling wave voltage) generated in the second power supply circuits V2a to V2d is applied to each electrode EL of the second transport body 33b, whereby the outer peripheral surface (transport surface TS) of the second transport body 33b is applied. As in the first transport body 33a, an electric field is formed that transports the positively charged developer T in the clockwise direction (transport direction TD) in FIGS. 2 and 9 along the transport surface TS. In the present specification, the transport surface TS of the second transport body 33b is also referred to as a first transport surface.

  In addition, in a region R1 between the first transport body 33a and the second transport body 33b and in the vicinity of the plane including the central axis TC1 and the central axis TC2, the positively charged developer T is transported to the first transport body. An electric field to be moved from the body 33a toward the second transport body 33b is formed.

  Accordingly, when the developer T transported on the transport surface TS of the first transport body 33a reaches the region R1, the developer T is subjected to the second force by the electrostatic force directed from the first transport body 33a to the second transport body 33b. Jump out toward the carrier 33b. Thereby, a part of the positively charged developer T reaches the transport surface TS of the second transport body 33b. The other developer T is transported along the transport surface TS of the first transport body 33a and returned to the state where it is deposited on the first auxiliary transport body 33c.

  In the present specification, in the area AR2 in the vicinity of the area R1 in the transport surface TS of the first transport body 33a, the transported developer T is supplied to the second transport body 33b as a developer supply target. It can be said that it is the second region. The second area AR2 is an area on the transport surface TS of the first transport body 33a and is an area other than the joint portion arrangement area AJ1 and an area other than the first area AR1.

  Accordingly, the joint portion JT1 of the first transport body 33a is located upstream in the transport direction TD from the first area AR1 (on the side opposite to the transport direction TD) and in the transport direction TD from the second area AR2. It can be said that it is arranged at a position on the downstream side (conveying direction TD side). In other words, the joint portion JT1 of the first transport body 33a extends in the transport direction TD from the downstream end in the transport direction TD of the second area AR2 to the upstream end in the transport direction TD of the first area AR1. It can be said that they are arranged at positions in the region.

Further, it can be said that the area AR3 in the vicinity of the area R1 in the transport surface TS of the second transport body 33b is a first area where the developer T is newly supplied to the transport surface TS. The first area AR3 is an area on the conveyance surface TS of the second conveyance body 33b and is an area other than the joint portion arrangement area AJ2.
The developer T that has reached the transport surface TS of the second transport body 33b is transported in the clockwise direction (transport direction TD) in FIG. 2 on the transport surface TS of the second transport body 33b.

  By the way, immediately after the control unit receives the print instruction signal, the potential of the latent image forming surface LS is the reference potential (+1000 [V]) at any position. On the other hand, the potential of the transport surface TS of the second transport body 33b is a potential (+150 to +650 [V]) lower than the reference potential.

  Accordingly, between the transport surface TS of the second transport body 33b and the latent image forming surface LS, the positively charged developer T is transferred from the latent image forming surface LS to any position in the latent image forming surface LS. An electric field to be moved to the transport surface TS of the second transport body 33b is formed. As a result, the positively charged developer T receives an electrostatic force from the latent image forming surface LS toward the transport surface TS of the second transport body 33b. As a result, the developer T continues to be transported on the transport surface TS of the second transport body 33b without moving toward the latent image forming surface LS.

  On the other hand, the third auxiliary transport body 33e is also connected to the first power supply circuits V1a to V1d similarly to the first auxiliary transport body 33c. Accordingly, the voltage (traveling wave voltage) generated in the first power supply circuits V1a to V1d is applied to each electrode EL of the third auxiliary transport body 33e, so that the Y direction of the third auxiliary transport body 33e is negative. On the side surface (transport surface TS), an electric field for transporting the positively charged developer T in the X-axis negative direction (transport direction TD) along the transport surface TS is formed. In the present specification, the transport surface TS of the third auxiliary transport body 33e is also referred to as a second transport surface.

  Accordingly, even when the developer T transported on the transport surface TS of the first transport body 33a is separated from the transport surface TS by gravity, centrifugal force, or the like, the developer T is transported to the first auxiliary transport. It is transported in the direction along the transport surface TS of the first transport body 33a by the body 33c and the third auxiliary transport body 33e.

  Similarly to the second carrier 33b, the second auxiliary carrier 33d and the fourth auxiliary carrier 33f are also connected to the second power supply circuits V2a to V2d. Accordingly, a voltage (traveling wave voltage) generated in the second power supply circuits V2a to V2d is applied to each electrode EL of the second auxiliary transport body 33d, so that the Y-axis positive direction of the second auxiliary transport body 33d. On the surface (transport surface TS) on the side, an electric field for transporting the positively charged developer T in the negative X-axis direction (transport direction TD) along the transport surface TS is formed. In the present specification, the transport surface TS of the second auxiliary transport body 33d is also referred to as a second transport surface.

  Furthermore, the voltage (traveling wave voltage) generated in the second power supply circuits V2a to V2d is applied to each electrode EL of the fourth auxiliary transport body 33f, so that the fourth auxiliary transport body 33f has a negative Y-axis direction. On the surface (transport surface TS) on the side, an electric field for transporting the positively charged developer T in the X-axis positive direction (transport direction TD) along the transport surface TS is formed.

  Therefore, even when the developer T transported on the transport surface TS of the second transport body 33b is separated from the transport surface TS by gravity, centrifugal force, or the like, the developer T is transported to the second auxiliary transport. It is transported in the direction along the transport surface TS of the second transport body 33b (transport direction TD) by the body 33d and the fourth auxiliary transport body 33f.

  In such a state, the control unit causes the scanner unit 42 to output the laser beam LB based on the image data at a predetermined timing. The output laser beam LB forms an image at a position corresponding to the image data on the latent image forming surface LS. As a result, the latent image forming surface LS is exposed at the position where the laser beam LB forms an image, and the absolute value of the charge amount at the same position decreases. As a result, the potential of the latent image forming surface LS is lowered at the exposed position, and the potential (+100 [in this example) is closer to the potential (0 [V]) of the drum body 31a than the reference potential (+1000 [V]). V]). In this way, an electrostatic latent image is formed on the latent image forming surface LS by the potential of the latent image forming surface LS.

  The portion where the electrostatic latent image is formed on the latent image forming surface LS by rotating the photosensitive drum 31 is an area between the second transport body 33b and the photosensitive drum 31, and the central axis TC2. And the position exposed to the laser beam LB in the electrostatic latent image when it reaches the region R2 in the vicinity of the plane including the central axis LC (opposite the developer supply hole 32c1) (exposed position). In contrast, an electric field is formed to move the positively charged developer T from the transport surface TS of the second transport body 33b to the latent image forming surface LS.

  As a result, the developer T moves from the transport surface TS of the second transport body 33b toward the latent image forming surface LS by electrostatic force based on this electric field and the charge (charge amount) of the developer T, It passes through the developer supply hole 32c1 and reaches the latent image forming surface LS. That is, the developer T is supplied to the latent image forming surface LS. In the present specification, in the area AR4 in the vicinity of the area R2 in the transport surface TS of the second transport body 33b, the transported developer T is supplied to the photosensitive drum 31 as a developer supply target. It can be said that this is the second area. The second area AR4 is an area on the transport surface TS of the second transport body 33b, is an area other than the joint portion arrangement area AJ2, and is an area other than the first area AR3.

  Therefore, the joint portion JT2 of the second transport body 33b is disposed at a position upstream of the first area AR3 in the transport direction TD and downstream of the second area AR4 in the transport direction TD. (See FIG. 9). In other words, the joint portion JT2 of the second transport body 33b extends in the transport direction TD from the downstream end in the transport direction TD of the second area AR4 to the upstream end in the transport direction TD of the first area AR3. It can be said that they are arranged at positions in the region.

  The developer T that has reached the latent image forming surface LS adheres only to a position exposed (exposed) by the laser beam LB in the latent image forming surface LS. In this way, the electrostatic latent image formed on the latent image forming surface LS is developed by the developer T, and an image of the developer T is formed on the latent image forming surface LS.

  In addition, the control unit controls the registration rollers 21 and 22 so that the image formed by the developer T formed on the latent image forming surface LS and the position on the paper P to which the image is to be transferred are matched. The paper P is conveyed between the photosensitive drum 31 and the transfer roller 51 at a predetermined timing.

  Then, the paper P reaches the transfer processing position (position where the latent image forming surface LS and the peripheral surface of the transfer roller 51 abut) (the paper P is exposed to the latent image forming surface LS of the photosensitive drum 31 and the transfer roller 51). The developer T that has adhered to the latent image forming surface LS at the transfer processing position moves onto the paper P and adheres to the paper P. In this way, the image of the developer T developed on the latent image forming surface LS is transferred onto the paper P.

  Next, when the paper P reaches the fixing unit, the developer T transferred onto the paper P is heated and pressurized. As a result, the developer T transferred onto the paper P is fixed on the paper P. Thereafter, when the paper P is conveyed and reaches the paper discharge unit, the paper P is discharged toward the paper discharge tray.

  When the discharge of the paper P is completed, the control unit stops the rotation of the photosensitive drum 31 and the transfer roller 51 that are controlled to be rotated. Further, the control unit controls the charger 41 and the transfer roller 51 that are controlled to be in a bias applied state so that a bias is not applied (a bias non-applied state).

  In this way, the laser printer 10 forms an image (image) represented by the image data included in the print instruction signal sent by the user on the paper P (prints on the paper P).

  As described above, according to the embodiment of the image forming apparatus and the developer supply apparatus of the present invention, the joint portion JT1 is the first area AR1 in which the new developer T is supplied to the first transport body 33a. The position in the upstream in the transport direction TD and downstream in the transport direction TD from the second area AR2 where the developer T is supplied from the first transport body 33a to the second transport body 33b (developer supply target). (See FIG. 9).

  As a result, even if the developer T being conveyed stays in the joint portion JT1, the developer T newly supplied to the first area AR1 smoothly reaches the second area AR2, so that the second conveyance is performed. There is no shortage of the developer T supplied to the body 33b. That is, it is possible to prevent the amount of the developer T supplied to the second conveyance body 33b from being different from the planned amount.

  Similarly, the joint portion JT2 is a position on the upstream side in the transport direction TD with respect to the first area AR3 where the developer T is supplied to the second transport body 33b and from the second transport body 33b to the photosensitive drum 31 ( It is disposed at a position downstream of the second area AR4 in which the developer T is supplied to the developer supply target) in the transport direction TD (see FIG. 9).

  As a result, even if the developer T being conveyed stays in the joint portion JT2, the developer T newly supplied to the first area AR3 smoothly reaches the second area AR4. There is no shortage of developer T supplied to 31. That is, it is possible to prevent the amount of the developer T supplied to the photosensitive drum 31 from being different from the planned amount.

  As described above, the amount of the developer T supplied from the developer supply device 32 to the photosensitive drum 31 can be brought close to the planned amount, so that the quality of the image formed on the paper P can be improved.

  Moreover, in the said embodiment, even if it is a case where the length of the 1st pair of edge | side of the board | substrate PS used in order to produce the 1st conveyance body 33a is longer than the outer periphery of the base material layer 33a1 (FIG. 6 (B)), and the end portion (downstream end portion) including the side EG2 is overlapped on the outer peripheral surface OTS of the end portion (upstream end portion) including the side EG1 to form the joint portion JT1. Has been. Therefore, since the developer T can pass through the joint portion JT1 without climbing the step, the developer T can be transported more smoothly than when the upstream end is overlapped on the outer peripheral surface OTS of the downstream end. Can do.

  In addition, in the above-described embodiment, the third auxiliary transport body 33e is opposed to the joint portion arrangement area AJ1 including the joint portion JT1 in the transport surface TS (first transport surface) of the first transport body 33a. (Second transport body) is disposed, and an electric field is formed to transport the developer T on the transport surface TS (second transport surface) of the third auxiliary transport body 33e in the transport direction TD. Accordingly, the strength of the electric field formed by the second transport body increases as the distance from the first transport surface increases. Therefore, even when the developer T moves away from the first transport surface, the developer T is removed. It is possible to prevent the force (transport force) transported in the transport direction TD from becoming excessively small.

  As a result, the development away from the first transport surface due to scattering caused by the collision between the developers T or an electric field (an electric field similar to the electric field EF2 in FIG. 11) that tries to keep the developer T away from the first transport surface. Since the agent T can be reliably conveyed in the vicinity of the joint portion JT1, the amount of the developer T retained in the joint portion JT1 can be reduced. Accordingly, since the developer T can be smoothly conveyed, it is possible to prevent the amount of the developer T supplied to the second conveyance body 33b from being different from the planned amount.

  Similarly, the second auxiliary transport body 33d (second transport body) is disposed so as to face the joint portion arrangement area AJ2 including the joint portion JT2 in the transport surface TS (first transport surface) of the second transport body 33b. ) Is disposed, and an electric field for transporting the developer T on the transport surface TS (second transport surface) of the second auxiliary transport body 33d in the transport direction TD is formed. As a result, the strength of the electric field formed by the second transport body increases as the distance from the first transport surface increases, so that the transport force is too small even when the developer T moves away from the first transport surface. Can be prevented. As a result, the development away from the first transport surface due to scattering caused by the collision between the developers T or an electric field (an electric field similar to the electric field EF2 in FIG. 11) that tries to keep the developer T away from the first transport surface. Since the agent T can be reliably conveyed in the vicinity of the joint portion JT2, the amount of the developer T retained in the joint portion JT2 can be reduced.

  Further, according to the above embodiment, the amount of the developer T that is transported in the transport direction TD in the state of being separated from the first transport surface in the vicinity of the joint portion JT2, the normal outward direction is the vertical upward direction. This can be increased as compared with the case where the joint portion JT2 is disposed at the position having the component. As a result, the amount of the developer T retained at the joint portion JT2 can be reduced. That is, since the developer T can be smoothly conveyed, it is possible to prevent the amount of the developer T supplied to the photosensitive drum 31 from being different from the planned amount.

  In addition, in the above embodiment, the first transport body 33a includes the endless coating layer 33a3 that forms the transport surface TS by covering the outer peripheral surface of the substrate layer 33a2 (curved substrate PS) seamlessly. According to this, the unevenness | corrugation of the conveyance surface TS in the joint part JT1 can be made small or eliminated compared with the case where the 1st conveyance body 33a is not provided with an endless coating layer. Accordingly, since the developer T can be smoothly conveyed, it is possible to prevent the amount of the developer T supplied to the second conveyance body 33b from being different from the planned amount.

  Similarly, the second transport body 33b includes an endless coating layer 33b3 that forms the transport surface TS by covering the outer peripheral surface of the substrate layer 33b2 (curved substrate PS) seamlessly. According to this, the unevenness | corrugation of the conveyance surface TS in the joint part JT2 can be made small or eliminated compared with the case where the 2nd conveyance body 33b is not provided with an endless coating layer. Therefore, since the developer T can be smoothly conveyed, it is possible to prevent the amount of the developer T supplied to the photosensitive drum 31 from being different from the planned amount.

  In addition, this invention is not limited to the said embodiment, A various modification can be employ | adopted within the scope of the present invention. For example, the developer supply device 32 in the above embodiment may be applied to an image forming apparatus that includes a plurality of sets of a photosensitive drum, a developer supply device, and a scanner unit and that can perform color printing.

  In the above-described embodiment, the developer T is configured to be positively charged. However, the developer T may be configured to be negatively charged. In this case, the photosensitive layer 31b is made of a negatively chargeable photoconductor, the polarity of the bias applied to the charger 41 and the transfer roller 51 is opposite to that in the above embodiment, and is generated in each circuit. It is preferable that the polarity of the voltage to be reversed is the opposite of that in the above embodiment.

  On the other hand, in the above embodiment, the voltage waveform generated by each of the first power supply circuits V1a to V1d and each of the second power supply circuits V2a to V2d is a rectangular waveform, but other than a sinusoidal waveform, a triangular waveform, etc. It may be a waveform of the shape.

  In the above embodiment, the first transport body 33a, the second transport body 33b, the first auxiliary transport body 33c, the second auxiliary transport body 33d, the third auxiliary transport body 33e, and the fourth auxiliary transport body Each power supply circuit provided with four power supply circuits (first power supply circuits V1a to V1d or second power supply circuits V2a to V2d) connected to each of the six transport bodies including the body 33f and connected to one transport body Although the phase of the generated voltage is different by 90 °, three power circuits are connected to each of the six carriers, and the voltage generated by each power circuit connected to one carrier is The phase may be different by 120 °.

  Further, in the above embodiment, the first transport body 33a is formed so that the shape of the transport surface TS of the first transport body 33a in a cross section obtained by cutting the first transport body 33a by a plane orthogonal to the Z axis is circular. However, it may be formed to have a closed curve other than a circle (for example, an ellipse, a polygon, etc.). Similarly, the second transport body 33b is formed such that the shape of the transport surface TS of the second transport body 33b in a cross section obtained by cutting the second transport body 33b along a plane orthogonal to the Z axis is a closed curve other than a circle. May be.

  In the above-described embodiment, both the first transport body 33a and the second transport body 33b are configured to transport the developer T by an electric field formed by applying a traveling wave voltage to the electrode group. In addition, only one of the first transport body 33a and the second transport body 33b may be configured to transport the developer T by the electric field. In this case, the other of the first transport body 33a and the second transport body 33b is preferably a roller that transports the developer T attached to the outer peripheral surface by being driven to rotate.

  In addition, in the above-described embodiment, each of the first transport body 33a and the second transport body 33b is configured to have one seam portion, but may be configured to have a plurality of seam portions. Good.

  In the above embodiment, the developer supply device 32 is arranged so that the direction from the top surface 32a to the bottom surface 32b coincides with the vertically downward direction, but the direction from the top surface 32a to the bottom surface 32b is vertical. You may arrange | position so that it may correspond with directions other than a downward direction.

  For example, when the developer supply device 32 is arranged so that the direction from the front surface 32c to the back surface 32d coincides with the vertically downward direction, the joint portion JT1 of the first transport body 33a is positioned on the back surface 32d side with respect to the plane PL1. In this case, it is preferable that the first region AR1 is disposed at a position upstream of the first region AR1 in the transport direction TD. Further, it is preferable that the joint portion JT2 of the second transport body 33b is disposed at a position on the back surface 32d side with respect to the plane PL2 and on the upstream side in the transport direction TD with respect to the first area AR3.

  Furthermore, in the said embodiment, although the shape of the board | substrate PS before being curved was a rectangular shape, shapes other than a rectangular shape may be sufficient. In this case, it is preferable that both ends of the substrate PS in a direction orthogonal to the direction in which the electrode EL extends (that is, the transport direction TD) are a pair of sides parallel to the direction in which the electrode EL extends. . Thereby, since electrode EL can be arrange | positioned to the position of the extreme vicinity of the said both ends of board | substrate PS, it can avoid that the density of electrode EL falls too much in a joint part.

  In the above embodiment, when the endless coating layer 33a3 substantially eliminates the unevenness on the transport surface TS formed by the joint portion JT1, the joint portion JT1 may be disposed at any position. Even when the unevenness on the transport surface TS formed by the joint portion JT1 is substantially eliminated, the upstream end or the downstream side of the substrate PS used to create the first transport body 33a. In the case where the density of the electrode EL in the joint portion JT1 is lower than the other portions because the electrode EL is not disposed at the end portion, the strength of the electric field formed in the joint portion JT1 is reduced. Accordingly, similarly to the case where the unevenness on the transport surface TS is formed by the joint portion JT1, the joint portion JT1 is located upstream of the first region AR1 in the transport direction TD and the second region AR2. It is preferable to arrange at a position downstream of the transport direction TD.

  Similarly, when the endless coating layer 33b3 substantially eliminates the unevenness on the transport surface TS formed by the joint portion JT2, the joint portion JT2 may be disposed at any position. Even when the unevenness on the transport surface TS formed by the joint portion JT2 is substantially eliminated, the upstream end portion or the downstream side of the substrate PS used to create the second transport body 33b. When the density of the electrode EL in the joint portion JT2 is lower than the other portions because the electrode EL is not disposed at the end portion, the unevenness on the transport surface TS is formed by the joint portion JT2. Similarly to the case, it is preferable that the joint portion JT2 is disposed at a position upstream of the first area AR3 in the transport direction TD and downstream of the second area AR4 in the transport direction TD. It is.

  In addition, in the said embodiment, each of the 1st conveyance body 33a and the 2nd conveyance body 33b does not need to be provided with the endless coating layer. In this case, the substrate PS used to create the first transport body 33a and / or the second transport body 33b has the same coating layer as the coating layer CF provided on the substrate of the first auxiliary transport body 33c. Is preferably provided.

In the above embodiment,
A transport surface TS, which is an outer surface among the surfaces formed by continuously arranging closed curves in one plane (plane orthogonal to the Z axis) in a direction orthogonal to the plane (Z axis direction), and a plurality of electrodes EL A transport body (a first transport body 33a or a second transport body 33b) having an electrode group that is included and separated from the plurality of electrodes EL along the transport surface TS.
By applying a traveling wave voltage to a plurality of electrodes EL included in the electrode group, the charged developer T on the transport surface TS is the same in a transport direction TD that is one of the directions parallel to the plane. Conveying means for forming an electric field that circulates along the conveying surface TS;
The developer T is supplied to the first region (AR1 or AR3) on the transport surface TS and the developer transported in the second region (AR2 or AR4) on the transport surface TS In the developer supply device 32 configured to move T toward a predetermined developer supply target (the second conveyance body 33b or the photosensitive drum 31),
The transport body (the first transport body 33a or the second transport body 33b) has a first pair of sides EG1 orthogonal to the first pair of sides and the first pair of sides having the same length as the closed curve. , EG2 and a rectangular substrate PS on which the electrode group is disposed, the second pair of sides of the first pair of sides draw the same closed curve and the second substrate PS. The pair of sides EG1, EG2 are formed by being deformed so as to be orthogonal to the plane (plane orthogonal to the Z-axis), and of the same transport body (first transport body 33a or second transport body 33b) The seam portion (TS1 or TS2) formed by the second pair of sides EG1 and EG2 is a position downstream of the second region in the transport direction TD and the same as the first region. Located in the upstream position in the transport direction TD A developer supply device 32 arranged, as can be said.

1 is a schematic sectional side view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a developer supply device side portion of a developer supply device and a photosensitive drum shown in FIG. 1. It is sectional drawing of the 1st conveying body and the 2nd conveying body which were shown in FIG. It is sectional drawing of the base material layer and board | substrate for demonstrating the process of creating the 1st conveyance body shown in FIG. It is the elements on larger scale of the board | substrate before being curved in the process of producing the 1st conveyance body shown in FIG. It is a partial expanded sectional view of the seam part formed in the process of creating the 1st conveyance object shown in Drawing 2. It is sectional drawing of the conveyance body before a coating | cover for explaining the process of forming an endless coating layer among the processes of creating the 1st conveyance body shown in FIG. 2, and a heat contraction tube. It is a partial expanded sectional view of the 1st auxiliary | assistant conveyance body shown in FIG. It is an expanded sectional view of the vicinity part of the 1st conveyance object shown in Drawing 2, and the 2nd conveyance object. It is the graph which showed the waveform of the voltage which the 1st power supply circuit connected to the electrode of the 1st auxiliary | assistant conveyance body shown in FIG. 8 generate | occur | produces. It is explanatory drawing which showed the change with respect to time of the electric field formed on the 1st auxiliary | assistant conveyance body shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Laser printer, 31 ... Photosensitive drum, 32 ... Developer supply apparatus, 33a ... 1st conveyance body, 33b ... 2nd conveyance body, 33a1, 33b1 ... Base material layer, 33a2, 33b2 ... Substrate layer, 33a3, 33b3 ... endless coating layer, 33c ... first auxiliary carrier, 33d ... second auxiliary carrier, 33e ... third auxiliary carrier, 33f ... fourth auxiliary carrier, 41 ... charger, 42 ... scanner unit 51, transfer roller, AR1, AR3, first region, AR2, AR4, second region, BF, base film, CF, coating layer, EG1, EG2, side, EL, ELa to ELd, electrode, IS,. Insulator between electrodes, JT1, JT2: joint portion, LS ... latent image forming surface, P ... paper, PS ... substrate, PT ... transport body before coating, SP ... developer containing space, T ... developer, TD ... transport direction , TS ... Conveying surface, TT Heat shrinkable tube, V1a~V1d ... the power supply circuit, V2a~V2d ... the power supply circuit.

Claims (3)

A flexible substrate on which a first electrode group consisting of a plurality of electrodes is disposed, and both ends of the substrate including an upstream end in a predetermined transport direction and a downstream end in the transport direction A first carrier having a substrate curved to form a seam portion;
By applying a traveling wave voltage to the first electrode group, a first electric field for transporting the developer in the transport direction is formed along the first transport surface which is the surface of the first transport body. 1 transport means;
A second electrode group comprising a plurality of electrodes is provided so as to extend along the conveyance direction, and a predetermined distance from a seam portion arrangement region including the seam portion of the first conveyance surface A second carrier arranged to face each other with a gap therebetween,
By applying a traveling wave voltage to the second electrode group, the developer is applied in the transport direction along the second transport surface, which is the surface of the second transport body on the first transport body side. A second transfer means for forming an electric field to be transferred;
And supplying the developer to a first region on the first transport surface and supplying the developer transported in a second region on the first transport surface to a developer supply target Developer supplying device. The developer supply device according to claim 1 ,
The seam portion is a direction along a normal line of the first conveyance surface, and a normal outward direction that is a direction from the first conveyance surface toward the outside of the first conveyance body is vertically downward. A developer supply device disposed at a position having a directional component. A developing agent supply device according to any one of claims 1 or claim 2,
An image forming apparatus comprising image forming means for forming an image on a recording medium with a developer supplied from the developer supply apparatus.

Images