JP4692225B2 - Developing device, toner particle carrying roller, image forming apparatus, image forming system, and toner particle carrying roller manufacturing method - Google Patents

Description

  The present invention relates to a developing device, a toner particle carrying roller, an image forming apparatus, an image forming system, and a toner particle carrying roller manufacturing method.

  As a developing device for developing using toner particles, a developing device including a toner particle carrying roller for carrying a toner particle contained in a toner particle containing body and developing a latent image is known (for example, Patent Document 1).

Such a developing device regulates the layer thickness of the toner particles carried on the toner particle carrying roller, and in order to charge the toner particles, the layer thickness brought into contact with the toner particle carrying roller carrying the toner particles. A regulating member is provided. Further, the surface of the toner particle carrying roller is sandblasted to have fine irregularities on the surface. When the toner particles are carried on the surface of the toner particle carrying roller and pressed against the layer thickness regulating member, the toner particles roll and be charged while rubbing against the irregular surface, the layer thickness regulating member, and the toner particles. In addition, a portion where no unevenness is formed is provided at the end of the toner particle carrying roller in the axial direction. In order to prevent the toner particles from leaking from the gap between the opening of the developing device where the toner particle carrying roller is exposed and the toner particle carrying roller, the portion where the unevenness is not formed is used. The restricting member is in contact.
JP 2003-263018 A

  Since the irregularities on the surface of the toner particle carrying roller of such a developing device are formed by sandblasting, the size, depth, shape, and arrangement of the recesses are not uniform. At this time, when the concave portion near the portion where the unevenness at the end portion in the axial direction of the toner particle carrying roller is not formed is deeper than the other portion, the toner particles that have entered the deeply formed portion are There is a possibility that the rolling property is poor and the battery is not properly charged. In addition, when the difference in height between the end of the toner particle carrying roller and the concave portion in the vicinity thereof becomes large, the layer thickness regulating member cannot follow the change in its shape, and between the toner particle carrying roller and the layer thickness regulating member. There is a problem that a gap is generated, and toner particles having poor charging leak from the gap and are scattered in the image forming apparatus, or the image may be fogged.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a developing device that charges toner particles satisfactorily and hardly generates a gap between the toner particle carrying roller and the layer thickness regulating member, An image forming apparatus having the developing device, an image forming system, and a toner particle carrying roller manufacturing method are realized.

The main aspect of the present invention has a central portion having a concave portion provided by a machining tool and a convex portion having a surface that does not contact the machining tool, and both end portions not to be machined, and carries toner particles. And a layer for regulating the layer thickness of the toner particles carried on the toner particle carrying roller in contact with the central portion and both ends of the toner particle carrying roller. A latent image developed by toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a lattice-shaped region, and the lattice is The developing device can be formed with a plurality of types of pitches in the direction, and the pitch of the recesses in the axial direction is shorter than the longest pitch among the plurality of types of pitches in the lattice .

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

  A toner particle carrying roller having a central part having a concave part provided by a machining tool and a convex part having a surface that does not contact the machining tool, and both end parts not to be machined, for carrying toner particles And a layer thickness regulating member for regulating the layer thickness of the toner particles carried on the toner particle carrying roller, which is in contact with the central part and the both end parts of the toner particle carrying roller. A developing device characterized by comprising:

  According to such a developing device, the top surface of the convex portion provided at the central portion of the toner particle carrying roller and the peripheral surface of both end portions are not processed by the processing tool because they are not in contact with the peripheral surface before processing. Will be configured. That is, the top surface of the convex portion and the peripheral surfaces of both ends are located on the peripheral surface of the same radius from the axis of the toner particle carrying roller. For this reason, even if the layer thickness regulating member for regulating the layer thickness of the toner particles is brought into contact with the central portion and both end portions of the toner particle carrying roller, the layer thickness regulating member is greatly bent in the axial direction. The contact is made in a substantially flat state. That is, since the layer thickness regulating member is not greatly bent, it is possible to prevent a gap from being generated between the toner particle carrying roller and the layer thickness regulating member. Further, the toner particles carried on the toner particle carrying roller are pressed almost uniformly by the layer thickness regulating member, so that the toner particles can be charged well.

In such a developing device, it is desirable that the concave portions are arranged in an axial direction at an equal pitch and formed in a spiral shape.
The toner particle carrying roller carries toner particles on its surface and develops the latent image on the image carrier. At this time, if irregularities having a non-uniform shape, depth, etc. are formed on the surface of the toner particle carrying roller, the toner particles that have entered the deep depression among the carried toner particles are not easily rolled and are not easily charged. In addition, in the case where concave portions are formed along the circumferential direction with a predetermined interval in the axial direction, the position of the image carrier facing the concave portions does not change in the axial direction. There is a possibility that the concentration of only the part that is opposed to increases. On the other hand, when the concave portion is formed along the axial direction, since the rotation direction of the toner particle carrying roller and the direction of the concave portion are substantially orthogonal to each other, the carried toner particles are difficult to roll and are not easily charged. According to the developing device having the toner particle carrying roller in which the concave portions are arranged at equal pitches in the axial direction and formed in a spiral shape as described above, the surface of the toner particle carrying roller is inclined with respect to the axial direction and the circumferential direction. Since the spiral recesses are formed at an equal pitch in the axial direction, the toner particles can be moved while rotating as the toner particle carrying roller rotates, so that the toner particles can be charged better. It is. In addition, since the position where the image carrier and the concave portion face each other changes in the axial direction and the circumferential direction as the toner particle carrying roller rotates, it is possible to suppress the occurrence of density unevenness in the developed toner image. Is possible.

In such a developing device, it is desirable that the concave portions are formed in two types with different inclination angles with respect to the axial direction and the circumferential direction.
According to such a developing device, since the toner particle carrying roller has two types of recesses having different inclination angles, the toner particles are moved in two types along the recess. Become. For this reason, it is possible to prevent the toner particles from moving and being biased in only one predetermined direction.

In such a developing device, it is desirable that the distance from the top surface of the convex portion to the bottom surface of the concave portion is constant.
According to such a developing device, since the distance from the top surface of the convex portion to the bottom surface of the concave portion in the concave and convex portion is constant, the amount of toner particles enters substantially uniformly throughout the concave portion. For this reason, the amount of toner particles carried on the toner particle carrying roller can be made substantially uniform over the entire area of the toner particle carrying roller.

In such a developing device, it is preferable that the distance from the top surface of the convex portion to the bottom surface of the concave portion is not more than twice the volume average particle diameter of the toner particles.
According to such a developing device, since the depth of the recess is not more than twice the volume average particle diameter of the toner particles, two or more toner particles entering the recess do not overlap in the depth direction in the recess. . For this reason, it is possible to charge the toner particles in the recesses uniformly by rolling them uniformly.

In such a developing device, it is desirable that the two types of concave portions intersect with each other to form a lattice shape.
According to such a developing device, since the two types of concave portions intersect, the toner particles that have started rolling along one concave portion may roll along the other concave portion from the middle. Is possible. For this reason, it is possible to more effectively suppress the deviation of the moving direction of the toner particles.

In such a developing device, it is desirable that the top surface of the convex portion surrounded by the concave portion is a rhombus.
According to such a developing device, since the top surface has a rhombus shape, the toner particles rolling in the two types of recesses reach a position intersecting with the other recess when each of them rolls by substantially the same distance. For this reason, it is possible to cause the toner particles to roll along the concave portions in substantially the same manner and to be charged in substantially the same manner.

In such a developing device, it is desirable that the two types of the concave portions are formed so that one of two diagonal lines on the top surface of each convex portion is along the circumferential direction.
According to such a developing device, since the concave portion is formed so that one of the two diagonal lines on the top surface of each convex section is along the circumferential direction, one of the diagonal lines along the circumferential direction is formed. From the apex angle, two types of recesses are formed with an inclination of the same angle toward the opposite direction of the axial direction. For this reason, the toner particles moved along the two types of recesses are moved substantially in the same manner toward both ends in the axial direction. Therefore, it is possible to move the toner particles without unevenness.

In such a developing device, it is desirable that the convex portion has a longer diagonal line along the circumferential direction of the two diagonal lines.
According to such a developing device, in the convex portion having a rhombic top surface, two apex angles positioned along the circumferential direction are acute angles, and two apex angles positioned along the axial direction are obtuse angles. For this reason, the toner particles can be configured to move more easily in the circumferential direction.

In the developing device, the top surface of the convex portion surrounded by the concave portion may be square.
According to such a developing device, since the top surface of the convex portion surrounded by the two types of concave portions is square, the convex portion is positioned along two apex angles positioned along the circumferential direction and along the axial direction. The two apex angles are right angles, and the two types of recesses have the same inclination with respect to the circumferential direction. For this reason, the toner particles can be easily moved in the circumferential direction and the axial direction as well. For this reason, it is possible to uniformly charge the toner particles by rolling them more uniformly.

In the developing device, it is preferable that the convex portion has a surface for supporting the toner particles.
According to such a developing device, since the convex portion has a surface for carrying toner particles, the toner particle carrying roller carries toner particles in both the concave portion and the convex portion. Therefore, by making the surface of the toner particle carrying roller face the image carrier, it is possible to develop the latent image while suppressing density unevenness in the entire portion of the image carrier facing the surface of the toner particle carrying roller. It is.

In such a developing device, it is preferable that the carried toner particles are pressed by a plane of the layer thickness regulating member.
According to such a developing device, the toner particles carried on the surface of the toner particle carrying roller are regulated in the layer thickness by the plane of the layer thickness regulating member, so that the surface of the toner particle carrying roller, in particular, The toner particles carried on the convex portions are not scraped off by the layer thickness regulating member. That is, it is possible to regulate the layer thickness of the toner particles in a state where the toner particles are supported on the concave portion and the convex portion of the toner particle supporting roller. Further, since the toner particles carried on the surface are pressed by the flat surface of the layer thickness regulating member, any one of the surface of the toner particle carrying roller, the layer thickness regulating member, and the toner particles and the toner particles are mutually connected. By rubbing, it is possible to charge the toner particles satisfactorily.

In such a developing device, the latent image developed by the toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a grid-divided region, and the grid is in the axial direction. It is possible to form with a plurality of types of pitches, and it is desirable that the pitch of the recesses in the axial direction is shorter than the longest pitch among the plurality of types of pitches in the lattice.
On the surface of the toner particle carrying roller, the amount of toner particles carried is larger in the recesses than in the recesses. For this reason, when the latent image is developed, there is a possibility that the density of the portion facing the recess is slightly increased. When the pitch in the axial direction of the concave portion is larger than the longest pitch among the plurality of types of pitches in the lattice, the toner is generated when the dot-like latent image formed in the region partitioned in the lattice shape is developed. Dots formed at a portion including the concave portion of the particle carrying roller and dots formed at a portion not including the concave portion are generated. In this case, periodic density unevenness occurs in the toner image in which the latent image is developed. However, according to the developing device as described above, any dot obtained by developing each dot-like latent image is formed at a portion including the concave portion of the toner particle carrying roller. For this reason, it is possible to suppress the occurrence of density unevenness due to the concave portion in the developed toner image.

In addition, a toner particle for supporting toner particles, having a central portion having a concave portion provided by a processing tool and a convex portion having a surface that does not contact the processing tool, and both end portions not to be processed. A carrier roller, and a layer thickness regulating member that is in contact with the central portion and both ends of the toner particle carrier roller and regulates the layer thickness of the toner particles carried on the toner particle carrier roller The recesses are arranged in an axial direction at an equal pitch and formed in a spiral shape, and the recesses are formed in two types with different inclination angles with respect to the axial direction, from the top surface of the projections The distance to the bottom surface of the recess is less than twice the volume average particle diameter of the toner particles, the two types of the recess intersect each other to form a lattice, and the two types of the recess intersect each other. And the convexity surrounded by the concave portion The two concave portions are formed such that one of two diagonal lines of the top surface of each convex portion is along the circumferential direction, and the convex portion is A latent image having a surface for carrying toner particles, the carried toner particles being pressed by a plane of the layer thickness regulating member, and developed by the toner particles carried on the toner particle carrying roller is , Having a dot-like latent image formed in a grid-divided region, the grid can be formed at a plurality of types of pitches in the axial direction, and the pitch of the recesses in the axial direction is the grid The developing device is shorter than the longest pitch among the plurality of types of pitches.
According to such a developing device, all of the above-described effects can be obtained, so that the object of the present invention can be achieved most effectively.

  In addition, a central portion having a concave portion provided by a processing tool and a convex portion having a surface that does not contact the processing tool, and both end portions not to be processed, the central portion and the both end portions are provided. It is also possible to realize a toner particle carrying roller in which the layer thickness of the toner particles carried by the layer thickness regulating member that is in contact therewith is regulated.

  In addition, a toner particle for supporting toner particles, having a central portion having a concave portion provided by a processing tool and a convex portion having a surface that does not contact the processing tool, and both end portions not to be processed. A carrier roller, and a layer thickness regulating member that is in contact with the central portion and both ends of the toner particle carrier roller and regulates the layer thickness of the toner particles carried on the toner particle carrier roller It is also possible to realize an image forming apparatus that forms an image using a developing device having

  Also, a computer, a central portion provided with a concave portion that is connected to the computer and is recessed by a machining tool, and a convex portion having a surface that does not contact the machining tool, and both end portions that are not to be machined. A toner particle carrying roller for carrying toner particles, and a layer of the toner particles carried on the toner particle carrying roller in contact with the central part and the both end parts of the toner particle carrying roller. An image forming system including an image forming apparatus that forms an image using a developing device having a layer thickness regulating member for regulating the thickness can also be realized.

A step of attaching flanges having shafts to both ends of a cylindrical cylindrical member; and the surface of the cylindrical member is concentric with the shaft while rotating the cylindrical member to which the flange is attached about the shaft. The two dies that are arranged parallel to each other and that form two different spiral grooves are rotated and the cut cylindrical member is rotated. When the die is pressed against the surface of the cylindrical member by moving between them in the axial direction, the concave portion formed by the machining tool in the central portion in the axial direction contacts the machining tool. And a step of forming a convex portion having a non-performing surface.
According to such a method of manufacturing a toner particle carrying roller, a concave portion formed by a machining tool in a central portion of the surface in the axial direction, a convex portion having a surface that does not contact the machining tool, and a portion that is not machined at both ends are provided. Having a toner particle supported on the surface thereof and contacting the layer thickness regulating member in a substantially flat state without causing a gap between the layer thickness regulating member and the toner particle carrying roller; and It is possible to manufacture a toner particle carrying roller capable of making the layer thickness of the toner particles carried almost uniform over the entire area of the toner particle carrying roller and charging the toner particles almost uniformly.

=== Overview of Image Forming Apparatus ===
A configuration example of a laser beam printer (hereinafter also referred to as a printer) 10 as an example of an image forming apparatus that forms an image using a developing device as a developing apparatus according to the present embodiment, with reference to FIGS. An operation example will be described. FIG. 1 is a diagram showing main components constituting the printer 10, and FIG. 2 is a diagram for explaining a configuration of a control unit provided in the printer 10. In FIG. 1, the vertical direction is indicated by arrows. For example, the paper feed tray 92 is disposed at the lower part of the printer 10, and the fixing unit 90 is disposed at the upper part of the printer 10.

<Configuration of Printer 10>
As shown in FIG. 1, the printer 10 includes a charging unit 30, an exposure unit 40, a developing device holding unit 50, and a primary transfer unit along the rotation direction of a photoconductor 20 as an example of an image carrier that carries a latent image. 60, an intermediate transfer body 70, and a cleaning unit 75, and further controls a secondary transfer unit 80, a fixing unit 90, a display unit 95 formed of a liquid crystal panel as a means for notifying a user, and these units. It has a control unit 100 that controls the operation as a printer.

  The photoreceptor 20 has a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable around a central axis. In the present embodiment, the photoreceptor 20 is indicated by an arrow in FIG. Rotate clockwise.

  The charging unit 30 is a device for charging the photoconductor 20, and the exposure unit 40 is a device for forming a latent image on the photoconductor 20 charged by irradiating a laser. The exposure unit 40 includes a semiconductor laser for emitting a laser beam as light, a polygon mirror unit that rotates a polygonal polygon mirror, and a plurality of types of lenses such as an F-θ lens. Based on an image signal input from a host computer (not shown) such as a word processor, the modulated photoconductor 20 is irradiated with a modulated laser beam. At this time, the laser beam emitted from the semiconductor laser is applied to the polygon mirror. The laser beam applied to the polygon mirror scans the photoreceptor 20 through the lens while changing the reflection angle by the rotation of the polygon mirror. Then, the laser beam is turned on / off at a predetermined timing, and a dot-like latent image is formed in a grid-divided area on the photoreceptor 20 that rotates at a predetermined speed. These dot-like latent images constitute a latent image. Here, since the dot-like latent image forms a latent image, it cannot be seen with the naked eye.

  The developing device holding unit 50 converts the latent image formed on the photoreceptor 20 into toner particles (hereinafter also referred to as toner) T accommodated in developing devices 51, 52, 53, and 54 as an example of a developing device, that is, The black (K) toner contained in the black developing device 51, the magenta (M) toner contained in the magenta developing device 52, the cyan (C) toner contained in the cyan developing device 53, and the yellow developing device 54. This is an apparatus for developing using yellow (Y) toner.

  In the present embodiment, the developing device holding unit 50 is capable of moving the positions of the four developing devices 51, 52, 53, and 54 by rotating. That is, the developing device holding unit 50 holds the four developing devices 51, 52, 53, and 54 by the four attaching / detaching portions 50a, 50b, 50c, and 50d, and the four developing devices 51, 52, and 53 are provided. , 54 can rotate around the central axis 50e while maintaining their relative positions. Each time the photosensitive member 20 rotates once, one of the four developing devices 51, 52, 53, 54 is selectively opposed to the photosensitive member 20, and the opposed developing devices 51, 52, 53, 54, The latent images formed on the photoreceptor 20 are sequentially developed with the toner contained in the toner 54. Details of each developing device will be described later.

  The primary transfer unit 60 is a device for transferring a single color toner image formed on the photoconductor 20 to the intermediate transfer body 70. When four color toners are sequentially transferred in a superimposed manner, the full color toner is transferred to the intermediate transfer body 70. An image is formed. The intermediate transfer member 70 is an endless belt, and is driven to rotate at substantially the same peripheral speed as the photosensitive member 20. The secondary transfer unit 80 is a device for transferring a single color toner image or a full color toner image formed on the intermediate transfer body 70 to a recording medium such as paper, film, or cloth.

  The fixing unit 90 is a device for fusing a single color toner image or a full color toner image transferred onto a recording medium onto a recording medium such as paper to form a permanent image. The cleaning unit 75 is provided between the primary transfer unit 60 and the charging unit 30 and has a rubber cleaning blade 76 that is in contact with the surface of the photoconductor 20. The cleaning unit 75 is disposed on the intermediate transfer body 70 by the primary transfer unit 60. After the toner image is transferred, the toner T remaining on the photoconductor 20 is scraped off and removed by the cleaning blade 76.

  As shown in FIG. 2, the control unit 100 includes a main controller 101 and a unit controller 102. An image signal is input to the main controller 101, and the unit controller 102 responds to an instruction based on the image signal. The unit is controlled to form an image.

  The main controller 101 is connected to a host computer via an interface 112, and includes an image memory 113 for storing an image signal input from the host computer, a CPU 111 for controlling the entire printer 10, and the like.

  The unit controller 102 includes a CPU 120, a memory 116 such as a RAM and a ROM, and units of the apparatus main body (charging unit 30, exposure unit 40, primary transfer unit 60, cleaning unit 75, secondary transfer unit 80, fixing unit 90, The display unit 95) and each drive control circuit for driving and controlling the developing device holding unit 50 are controlled, and each unit is controlled based on a signal input from the main controller 101.

<Operation of Printer 10>
Next, the operation of the printer 10 will be described with reference to other components.
First, when an image signal from a host computer (not shown) is input to the main controller 101 of the printer 10 via the interface (I / F) 112, the photosensitive device is controlled by the unit controller 102 based on a command from the main controller 101. The developing roller 510 and the intermediate transfer member 70 provided on the body 20, the developing devices 51, 52, 53, and 54 rotate. The photoconductor 20 is charged by the charging unit 30 at the charging position while rotating.

The charged region of the photoconductor 20 reaches the exposure position as the photoconductor 20 rotates, and a latent image corresponding to image information of the first color, for example, yellow Y, is formed by the exposure unit 40. At this time, the developing device holding unit 50 positions the yellow developing device 54 containing yellow (Y) toner at a developing position facing the photoconductor 20.
The latent image formed on the photoconductor 20 reaches the development position as the photoconductor 20 rotates, and is developed with yellow toner by the yellow developing device 54. As a result, a yellow toner image is formed on the photoreceptor 20.
The yellow toner image formed on the photoconductor 20 reaches the primary transfer position as the photoconductor 20 rotates, and is transferred to the intermediate transfer body 70 by the primary transfer unit 60. At this time, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer unit 60. During this time, the secondary transfer unit 80 is separated from the intermediate transfer member 70.

By repeating the above processing for the second color, the third color, and the fourth color, the four color toner images corresponding to the respective image signals are transferred onto the intermediate transfer body 70 in an overlapping manner. . As a result, a full color toner image is formed on the intermediate transfer member 70.
The full-color toner image formed on the intermediate transfer body 70 reaches the secondary transfer position as the intermediate transfer body 70 rotates, and is transferred to a recording sheet as a recording medium by the secondary transfer unit 80. The recording paper is conveyed from the paper feed tray 92 to the secondary transfer unit 80 via the paper feed roller 94 and the registration roller 96. When performing the transfer operation, the secondary transfer unit 80 is pressed against the intermediate transfer body 70 and a secondary transfer voltage is applied.
The full-color toner image transferred to the recording paper is heated and pressurized by the fixing unit 90 and fused to the recording paper. On the other hand, after the primary transfer position has elapsed, the toner remaining on the surface of the photoreceptor 20 is scraped off by the cleaning blade 76 to prepare for charging for forming the next latent image. The toner scraped off is collected in a waste toner container.

=== Overview of Developer ===
Next, a configuration example of the developing device will be described with reference to FIGS. FIG. 3 is a perspective view of the yellow developing device. FIG. 4 is a cross-sectional view showing the main components of the yellow developing device. FIG. 5 is a perspective view showing the developing device with the developing roller removed. The cross-sectional view shown in FIG. 4 is a view showing a cross section obtained by cutting the yellow developing device along a plane perpendicular to the longitudinal direction shown in FIG. 4, the vertical direction is indicated by arrows as in FIG. 1. For example, the central axis of the developing roller 510 is below the central axis of the photoconductor 20. Further, in FIG. 4, the yellow developing device 54 is shown in a state where the yellow developing device 54 is located at a developing position facing the photoconductor 20.

  The developing device holding unit 50 includes a black developing device 51 containing black (K) toner, a magenta developing device 52 containing magenta (M) toner, a cyan developing device 53 containing cyan (C) toner, and yellow. (Y) Although the yellow developing unit 54 containing toner is provided, the configuration of each developing unit is the same, so the yellow developing unit 54 will be described below.

<Configuration of Yellow Developer 54>
The yellow developing unit 54 includes a housing 540 that accommodates toner T, a developing roller 510 as an example of a toner particle carrying roller for carrying toner, a toner supply roller 550 for supplying toner to the developing roller 510, and a developing roller 510. A regulating blade 560 as an example of a layer thickness regulating member for regulating the layer thickness of the toner carried on the toner, an upper seal 520 for sealing the upper gap between the housing 540 and the developing roller 510, and development with the housing 540 An end seal 527 for sealing a gap on the end side with the roller 510 is provided.

  The housing 540 is manufactured by welding an integrally molded resin upper housing portion 542 and lower housing portion 544, and a toner storage portion serving as a storage portion for storing the toner T therein. 530 is formed. The toner storage portion 530 is divided into two toner storage portions, that is, a first toner storage portion 530a and a second toner, by a partition wall 545 for partitioning the toner T that protrudes inwardly (in the vertical direction in FIG. 4) from the inner wall. It is divided into the accommodating portion 530b.

  The upper portions of the first toner storage portion 530a and the second toner storage portion 530b communicate with each other. In the state shown in FIG. 4, the movement of the toner T is restricted by the partition wall 545. However, when the developing device holding unit 50 rotates, the toner stored in the first toner storage portion 530a and the second toner storage portion 530b is temporarily moved to the upper communicating side of the developing position. When the toner is collected and returns to the state shown in FIG. 4, the toners are mixed and returned to the first toner storage portion 530a and the second toner storage portion 530b. That is, the toner T in the developing device is agitated by the rotation of the developing device holding unit 50. For this reason, in this embodiment, the stirring member is not provided in the toner storage portion 530, but a stirring member for stirring the toner T stored in the toner storage portion 530 may be provided. As shown in FIG. 4, the housing 540 has an opening 572 in the lower portion, and a developing roller 510 described later is provided so as to face the opening 572.

  The toner supply roller 550 includes an elastic roller portion 550a formed of, for example, urethane foam, and a shaft body 550b that serves as a rotation center of the roller portion 550a. The toner supply roller 550 is supported by the housing 540 at both ends of the shaft body 550b, so that the toner supply roller 550 is rotatably supported around the shaft body 550b. The roller portion 550 a is accommodated in the first toner accommodating portion 530 a (inside the housing 540) of the housing 540 and supplies the toner T accommodated in the first toner accommodating portion 530 a to the developing roller 510. The toner supply roller 550 is provided vertically below the first toner storage portion 530a. The toner T accommodated in the first toner accommodating portion 530a is supplied to the developing roller 510 by the toner supply roller 550 below the first toner accommodating portion 530a. Further, the toner supply roller 550 peels off the excess toner T remaining on the developing roller 510 after development from the developing roller 510.

  The toner supply roller 550 and the developing roller 510 are assembled to the housing 540 while being pressed against each other. Therefore, the roller portion 550a of the toner supply roller 550 is in contact with the developing roller 510 in an elastically deformed state. The toner supply roller 550 rotates in a direction (clockwise in FIG. 4) opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 4). The shaft body 550b is below the rotation center axis of the developing roller 510.

  The developing roller 510 carries the toner T and conveys it to a developing position facing the photoconductor 20. The developing roller 510 is made of metal and is made of an aluminum alloy such as 5056 aluminum alloy or 6063 aluminum alloy, or an iron alloy such as STKM, and is subjected to nickel plating, chrome plating, or the like as necessary. May be. On the surface of the developing roller 510, a groove-like recess (hereinafter also referred to as a groove) formed in a spiral shape at the center in the axial direction of the developing roller 510 is provided. The surface shape of the developing roller 510 will be described in detail later.

  Further, as shown in FIG. 3, the developing roller 510 is supported at both ends in the longitudinal direction, and is rotatable about the central axis. As shown in FIG. 4, the developing roller 510 rotates in a direction (counterclockwise in FIG. 4) opposite to the rotation direction of the photoconductor 20 (clockwise in FIG. 4). The central axis is below the central axis of the photoconductor 20.

  As shown in FIG. 4, there is a gap between the developing roller 510 and the photoconductor 20 in a state where the yellow developing device 54 faces the photoconductor 20. That is, the yellow developing device 54 develops the latent image formed on the photoconductor 20 in a non-contact state. When developing the latent image formed on the photoconductor 20, an alternating electric field is formed between the developing roller 510 and the photoconductor 20.

  The regulating blade 560 applies a charge to the toner T carried on the developing roller 510 and regulates the layer thickness of the toner T carried on the developing roller 510. The regulation blade 560 has a rubber part 560a and a rubber support part 560b. The rubber part 560a is made of silicon rubber, urethane rubber or the like, and the rubber support part 560b is a thin plate having spring properties such as phosphor bronze or stainless steel. The rubber portion 560a is supported on the short side of the rubber support portion 560b along the longitudinal direction of the rubber support portion 560b, and the other end side of the rubber support portion 560b is supported by the blade support metal plate 562. In this state, it is attached to the housing 540 via the blade support sheet metal 562. Further, a blade back member 570 made of malt plane or the like is provided on the side opposite to the developing roller 510 side of the regulating blade 560.

  Here, the rubber portion 560 a is pressed from the central portion of the developing roller 510 to both ends by the elastic force due to the bending of the rubber support portion 560 b. Further, the blade back member 570 prevents the toner T from entering between the rubber support portion 560b and the housing 540, stabilizes the elastic force due to the bending of the rubber support portion 560b, and provides rubber from the back of the rubber portion 560a. The rubber portion 560 a is pressed against the developing roller 510 by urging the portion 560 a toward the developing roller 510. Therefore, the blade back member 570 improves the uniform contact property of the rubber portion 560a to the developing roller 510.

  The end of the regulating blade 560 opposite to the side supported by the blade support metal plate 562, that is, the tip is not in contact with the developing roller 510, and a portion away from the tip by a predetermined distance is the developing roller. 510 is in contact with a width. In other words, the regulating blade 560 is not in contact with the developing roller 510 at the edge, but is in contact with the antinode on the flat surface of the rubber portion 560a. The regulating blade 560 is disposed so that the tip thereof faces the upstream side in the rotation direction of the developing roller 510, and is in a so-called counter contact. The contact position where the regulating blade 560 contacts the developing roller 510 is below the central axis of the developing roller 510 and below the central axis of the toner supply roller 550.

  The rubber support portion 560b is longer than the rubber portion 560a in the axial direction of the developing roller 510, and extends outward from both ends of the rubber portion 560a. An end seal 527 made of, for example, a nonwoven fabric having a thickness thicker than that of the rubber portion 560a is attached to the same surface as the rubber portion and 560a at the extended portion of the rubber support portion 560b. At this time, the end surface of the rubber portion 560 a in the axial direction is in contact with the side surface of the end seal 527.

  The end seal 527 is provided so as to come into contact with both end portions of the surface of the developing roller 510 where no groove portion is provided when the developing roller 510 is attached, and has a width extending from the end portion of the developing roller 510 to the outside. is doing. Further, the end seal 527 extends sufficiently longer than the tip of the rubber portion 560 a of the regulating blade 560. When the regulating blade 560 is attached to the housing 540, the end seal 527 is placed along a portion of the housing 540 formed so as to face the outer peripheral surface of the developing roller 510, and closes the gap between the housing 540 and the developing roller 510. .

  The upper seal 520 prevents the toner T in the yellow developing device 54 from leaking out of the device, and collects the toner T on the developing roller 510 that has passed through the developing position into the developing device without being scraped off. The upper seal 520 is a seal made of a polyethylene film or the like. The upper seal 520 is supported by a seal support sheet metal 522 and is attached to the housing 540 via the seal support sheet metal 522. A seal urging member 524 made of malt plain or the like is provided on the opposite side of the upper seal 520 from the developing roller 510 side. The upper seal 520 is developed by the elastic force of the seal urging member 524. 510 is pressed. The contact position at which the upper seal 520 contacts the developing roller 510 is above the central axis of the developing roller 510.

<Operation of Yellow Developer 54>
In the yellow developing device 54 configured as described above, the toner supply roller 550 supplies the toner T accommodated in the toner accommodating portion 530 to the developing roller 510. The toner T supplied to the developing roller 510 reaches the contact position of the regulating blade 560 as the developing roller 510 rotates, and when passing through the contact position, an electric charge is applied and the layer thickness is regulated. Is done.

  The charged toner T on the developing roller 510 reaches a developing position facing the photoconductor 20 by further rotation of the developing roller 510, and a latent image formed on the photoconductor 20 under an alternating electric field at the developing position. For development. The toner T on the developing roller 510 that has passed the developing position by further rotation of the developing roller 510 passes through the upper seal 520 and is collected in the developing device without being scraped off by the upper seal 520. Further, the toner T still remaining on the developing roller 510 can be peeled off by the toner supply roller 550.

=== Surface shape of developing roller ===
FIG. 6 is a conceptual diagram for explaining the surface shape of the developing roller. FIG. 7 is a cross-sectional view for explaining a cross section when the developing roller is cut along a plane passing through an axis. In FIG. 6, the groove portion as the concave portion on the surface of the developing roller 510 is shown by a straight line for convenience, but since the groove portion is formed in a spiral shape, the groove portion is formed so that it looks exactly like a curve.

  The developing roller 510 is provided with a concavo-convex portion for supporting toner particles in the central portion 510a in the axial direction, and both end portions 510b have smooth peripheral surfaces so that the end seals 527 are in close contact with each other.

  As shown in FIG. 6, in the central portion 510 a of the developing roller 510 in this embodiment, a spiral groove 511 that is inclined with respect to the axial direction and the circumferential direction of the developing roller 510 and is formed at an equal pitch in the axial direction. Is formed. The groove portion 511 is formed in two types with different inclination angles with respect to the axial direction and the circumferential direction of the developing roller 510. The two types of groove portions 511 intersect with each other to form a lattice shape, and the top surface 512a of the convex portion 512 surrounded by the two types of groove portions 511 is formed in a substantially square shape. Further, the two types of the groove portions 511 are formed so that one of the two diagonal lines of the square of the top surface 512a of the convex portion 512 is along the circumferential direction.

  That is, one of the two types of grooves 511 is formed in a spiral shape so as to form an angle of 45 ° clockwise with the axis of the developing roller 510, and the other is counterclockwise with the axis of the developing roller 510. It is formed in a spiral shape so as to form an angle of 45 ° in the direction. For this reason, the angle at which one groove 511a and the other groove 511b intersect is 90 °. In addition, since the pitch in the axial direction of the developing roller 510 of the one groove portion 511a and the other groove portion 511b is equal, the shape of the top surface 512a of the convex portion 512 surrounded by the two types of groove portions is substantially square. It becomes.

  As shown in FIG. 7, the two types of groove portions 511 are each formed at an interval of 80 μm in the axial direction of the developing roller 510, and an inclined portion 511 d extending from the top surface 512 a of the convex portion 512 to the bottom surface 511 c of the groove portion 511. Is formed such that the intersecting angle α of the virtual plane obtained by extending the two inclined surfaces forming the groove 511 in the direction of the axis C is 90 °.

  Further, the depth of the groove portion 511, that is, the distance from the top surface 512a of the convex portion 512 to the bottom surface 511c of the groove portion 511 is formed to be constant at about 7 μm. Here, the volume average particle diameter of the toner is about 5 to 10 μm, and the depth of the groove 511 is set to be not more than twice the volume average particle diameter of the toner.

  Such a developing roller 510 is formed by rolling. FIG. 8 is a diagram for explaining how the developing roller 510 is formed by rolling. FIG. 9 is a diagram illustrating a procedure for forming the developing roller.

The developing roller 510 is formed from a cylindrical hollow material.
The cylindrical material is first cut to a length that can form a central portion 510a for carrying toner as the developing roller 510 and an end portion 510b with which the end seal 527 abuts, and the cylindrical member 515 is cut out. (S001). In the cylindrical member 515, a step portion 510c (FIG. 6) for fitting the flange 513 having the shaft of the developing roller 510 is formed in the inner peripheral portion of both end portions by cutting (S002). Here, the flange 513 includes a disk-shaped flange main body 513a having a diameter that is press-fitted into the formed stepped portion 510c, and a shaft portion 513b that protrudes perpendicularly to the disk surface from the center thereof. ing.

  Next, the flange 513 having the shaft portion 513b is fitted into the cylindrical member 515 having the step portion 510c formed inside the both end portions so that the shaft portion 513b protrudes outward of the cylindrical member (S003). .

  Thereafter, the cylindrical member 515 in which the flange 513 is fitted is supported by the shaft portions 513b at both ends and rotated around the shaft, and the outer peripheral surface of the cylindrical member 515 is slightly cut over the entire circumference, thereby The surface of the cylindrical member 515 is polished so that the entire region is concentric with the shaft, that is, a certain distance L from the shaft, thereby forming the non-rolled developing roller 509 (S004).

  The cylindrical member 515 whose surface has been polished is rolled by an apparatus having a die 900 as two types of processing tools as shown in FIG. 8 to form two types of grooves 511a and 511b on the surface (S005). ). The rolling device arranges the workpiece (here, the non-rolled processing developing roller 509) while the two types of dies 900 arranged at opposite positions are rotating in the same direction, and the two types of dies 900 are arranged. The unrolled developing roller 509 is pressed, and the unrolled developing roller 509 is conveyed in the axial direction while rotating in the direction opposite to the die 900. The die 900 is provided with blades 900a for forming the above-described grooves 511a and 511b. The blades 900a are formed on the surface of the non-roll processed developing roller 509 with the blades. An inclination is provided so that the grooves 511a and 511b are orthogonal. Here, the part where the die 900 is brought into contact with the surface of the non-rolling processing developing roller 509 is the blade 900a. However, the rolling process does not actively cut the work, but the work is crushed by the pressing force. Acts to form a depression. Further, during this rolling, the non-rolled developing roller 509 is not contacted with the die 900 at both ends 510b, leaving a smooth surface without unevenness at both ends 510b. deep. That is, the top surfaces 512a of the convex portions 512 which are arranged with the concave portion interposed between the central portions 510a of the developing roller 510 and the dice 900 are not in contact with each other, and the convex portions where the dice 900 are not in contact with the central portion 510a. The top surface 512a of 512 and both ends 510b not to be processed by rolling remain cut so that the distance L from the axis C does not contact with the die 900 and is constant from the axis C, etc. Located at a distance. The surface 510d of the developing roller 510 is substantially covered with the bottom surfaces 511c of the grooves 511a and 511b that are recessed by the contact of the die 900 and the non-processed surface that the die 900 does not contact.

  The developing roller 510 formed by rolling may be subjected to, for example, electroless Ni—P plating, electroplating, or hard chrome plating, if necessary.

  To such a developing roller 510, toner is supplied from the toner supply roller 550 between the end seals 527 abutted at both ends 510b, and the thickness of the toner layer is regulated at the pressing position of the regulation blade 560. Is done. At this time, the regulating blade 560 is pressed across both end portions 510b and the central portion 510a of the developing roller 510, but the both end portions 510b of the developing roller 510 and the top surface 512a of the convex portion 512 are at a distance from the axis C. Since L is constant, the regulating blade 560 presses the developing roller 510 in a substantially flat state without being largely bent. For this reason, for example, the regulating blade 560 that is in contact with the central portion 510a and both end portions 510b of the developing roller 510 does not bend greatly in the axial direction, and is contacted in a substantially flat state. become. That is, it is possible to prevent an extremely large gap from being generated between the developing roller 510 and the regulating blade 60 by preventing the regulating blade 560 from being bent greatly.

  Further, the convex portions 512 of the surface 510d of the developing roller 510 are arranged so that the top surfaces 512a of the convex portions 512 arranged with the groove portions 511 as the concave portions are located at a certain distance L from the axis C. The top surface 512 a of 512 is located on the peripheral surface formed with a single radius from the developing roller 510. Therefore, for example, when the flat surface of the regulating blade 560 is pressed toward the developing roller 510 in order to regulate the layer thickness of the carried toner particles T, the toner carried on the top surface 512a of each convex portion 512 Since the particles are similarly pressed, the layer thickness of the toner particles T carried on the developing roller 510 can be made substantially uniform over the entire area of the developing roller 510. In particular, since the distance from the top surface 512a of the convex portion 512 to the bottom surface 511c of the groove portion 511 in the concavo-convex portion that becomes the central portion 510a of the developing roller 510 is constant, the amount of toner particles T enters substantially uniformly throughout the groove portion 511. become. Therefore, the amount of toner particles T carried on the developing roller 510 can be made substantially uniform throughout the developing roller 510. Further, since the distance from the top surface 512a of the convex portion 512 to the bottom surface 511c of the groove portion 511 is not more than twice the volume average particle size, the toner layer formed by the toner particles entering between the developing roller 510 and the regulating blade 560 is formed. The layer thickness of the toner can be less than or equal to two toner particles. That is, a large amount of toner particles do not enter the groove portion 511, and most of the toner particles come into contact with either the surface 510 d of the developing roller 510 or the surface of the regulating blade 560 when pressed by the regulating blade 560. Accordingly, the toner particles T are similarly pressed and rolled easily, and the toner particles do not easily stay in the groove portion 511, so that the toner particles T can be charged uniformly and satisfactorily. For this reason, the toner particles are reliably carried on the developing roller 510 and used for development, and in combination with the fact that no extremely large gap is generated between the surface 510d of the developing roller 510 and the regulating blade 560, It is possible to prevent the toner particles T from leaking outside the developing devices 51, 52, 53, 54.

  FIG. 10 is a view for explaining a state in which the regulating blade is in contact with the developing roller carrying toner particles.

  In particular, the groove portion 511 of the developing roller 510 of the present embodiment has a depth of 7 μm, which is almost 1 time as compared with the volume average particle diameter of the toner particles T. For this reason, since the regulating blade 560 is made of rubber and follows the unevenness of the surface 510 d of the developing roller 510, the toner layer having a thickness corresponding to one toner particle on the entire surface of the developing roller 510 without overlapping the toner particles T. Can be formed. By forming a toner layer having a single particle thickness on the surface 510d of the developing roller 510 in this manner, each toner particle T can be reliably charged in the entire region including the convex portion 512 and the groove portion 511 of the central portion 510a. It is possible to reliably carry the toner on the developing roller 510 to improve transferability during development and to prevent toner from leaking outside the developing device.

  That is, if unevenness having a non-uniform size, depth, shape, or the like is formed on the surface 510d of the developing roller 510, the toner particles that enter the deep recesses of the carried toner particles are difficult to roll and are not easily charged. . In addition, when grooves along the circumferential direction are formed at predetermined intervals in the axial direction, the position in the axial direction of the photoconductor 20 facing the groove does not change even when the photoconductor 20 rotates. In the developed toner image, there is a tendency that only the portion facing the groove portion has a high density. On the other hand, when the groove portion is formed along the axial direction, the rotation direction of the toner particle carrying roller and the direction of the groove portion are almost orthogonal to each other, so that the carried toner particles are difficult to roll and are not easily charged.

  According to the developing devices 51, 52, 53, and 54 and the developing roller 510 of the present embodiment, the surface 510d of the developing roller 510 is inclined with respect to the axial direction and the circumferential direction and has a spiral groove portion at an equal pitch in the axial direction. Since 511 is formed, the toner particles T are moved while being rotated as the developing roller 510 rotates, so that the toner particles T can be charged satisfactorily. Further, as the developing roller 510 rotates, the position where the photoconductor 20 and the groove 511 face each other changes sequentially in the axial direction and the circumferential direction, so that it is possible to suppress the occurrence of density unevenness in the developed toner image. Is possible.

  Further, since the developing roller 510 of the present embodiment has two types of groove portions 511a and 511b having different inclination angles, the toner particles T are moved in two types of directions along the groove portions 511a and 511b. It will be. For this reason, it is possible to prevent the toner particles T from moving and being biased in only one predetermined direction. Further, since the two types of the groove portions 511a and 511b intersect each other to form a lattice shape, the toner particles T that have started to roll along the one groove portion 511a (511b) are transferred from the middle to the other. It is possible to roll along the groove part 511b (511a). For this reason, it is possible to more effectively suppress the deviation of the moving direction of the toner particles T.

  Furthermore, since the top surface 512a of the convex portion 512 surrounded by the two types of groove portions 511 is a square, and one diagonal line of the square is along the circumferential direction, the convex portion 512 is positioned along the circumferential direction. The two apex angles and the two apex angles positioned along the axial direction are both right angles, and the two types of grooves 511a and 511b have the same angle of inclination with respect to the circumferential direction and the axial direction. . For this reason, the toner particles T can be easily moved in the circumferential direction and the axial direction as well. For this reason, it is possible to uniformly charge the toner particles by rolling them more uniformly.

  Further, the toner particle T carried on the surface of the developing roller 510 has its layer thickness restricted by the plane of the rubber part 560 a of the restriction blade 560, so that the toner particle T is carried on the surface of the developing roller 510, particularly the convex part 512. The toner particles T are not completely scraped off by the regulating blade 560. That is, it is possible to regulate the layer thickness of the toner particles T in a state where the toner particles T are carried on the groove portions 511 and the convex portions 512 of the developing roller 510. Further, since the toner particles T carried on the surface 510d are pressed by the flat surface of the regulating blade 560, any one of the surface of the developing roller 510, the regulating blade 560, and the toner particles and the toner particles T are mutually connected. It is possible to charge well by rubbing.

  By the way, the laser beam printer forms a latent image on the photoconductor 20 using the laser beam as described above, and develops the formed latent image with toner carried on the developing roller 510. At this time, a dot-like latent image is formed on a so-called screen on the photosensitive member 20 by turning the laser beam scanned in the main scanning direction (axial direction) on and off. These dot-like latent images constitute a latent image.

  Further, in the case of the developing roller 510 having the groove portion (concave portion) 511 and the convex portion 512 that are clearly distinguished as in this embodiment, for example, more toner particles T are placed in the groove portion 511 than in the convex portion 512. There is a drowning in. In this case, in the toner image, there is a difference in density between the portion developed by the groove portion 511 and the portion developed by the convex portion 512. In particular, an image having no large area, such as a character or a line drawing, has little influence, but in the case of an image having a large area such as a photograph or an illustration, uneven density may be noticeable. Such a phenomenon becomes more prominent when the pitch in the axial direction of the grooves 511 formed in the developing roller 510 is larger than the pitch of the lattice in the main scanning direction of the screen described above. This is because even if the dots should originally be formed with the same density, the density differs depending on whether the dots are developed in the groove 511 of the developing roller 510 or the convex part 512.

  For this reason, the developing roller 510 of the present embodiment has a smaller pitch in the axial direction of the grooves 511 formed in the developing roller 510 than the longest pitch of the lattice when forming an image having an area such as a photograph or illustration. . Here, the pitch of the lattice in the main scanning direction of the latent image when forming an image having a large area such as a photograph or illustration is not the pitch between dots in the highest resolution image that can be formed by the laser beam printer. This is because when a laser beam printer forms an image with a large area such as a photograph or illustration, dots are formed at a resolution lower than the maximum resolution of the printer, and each dot has gradation. This is to improve the overall image quality.

  FIG. 11 is a diagram for explaining pitches in the screen and the latent image. As shown in the figure, for example, if the maximum resolution of the printer is 600 dpi (pitch 42.5 μm) and the resolution of the latent image is 600 dpi, the area where the dot-like latent image can be formed is 42.5 μm pitch. Divided into a lattice. For this reason, gradation can be expressed only in each partitioned area with or without a dot-like latent image (the upper part of FIG. 11).

  Therefore, when forming an image having a large area, for example, three dot-like latent images at a resolution of 600 dpi can be used as one dot-like latent image, and the semiconductor laser can respond to three dot-like latent images at a resolution of 600 dpi. The gray scale is expressed by changing the length of time during which the laser beam is emitted within a long time (lower part of FIG. 11). In this case, the resolution when forming an image having a large area is 200 dpi, and the area where the dot-like latent image can be formed is partitioned into a grid of 127.5 μm pitch. For this reason, the developing roller 510 according to the present embodiment is configured such that each pitch of the latent images formed in the lattice-divided region of 200 dpi, that is, 127.5 μm pitch, is set by setting the pitch of the groove portions 511 in the axial direction to 80 μm. The dot-like latent image is developed at a portion including the groove portion 511 and the convex portion 512 of the developing roller 510, and density unevenness is prevented from occurring in the developed toner image. In the present embodiment, the maximum resolution of the laser beam printer is 600 dpi, and the pitch in the axial direction of the area partitioned in a lattice form that can form a dot-like latent image when an image such as a photograph is formed is 127.5 μm. The example in which the pitch in the axial direction of the groove 511 of the developing roller 510 is 80 μm has been described. However, the pitch in the axial direction of the groove 511 in the developing roller 510 is not limited to this. It is only necessary that the pitch is smaller than the pitch in the axial direction of the area partitioned in the form of a lattice where the dot-like latent image is formed by the image. In particular, when the maximum axial distance between the adjacent groove 511 and the convex portion 512 is smaller than a grid-divided region that can form a dot-like latent image, one dot-like latent image is Since development is performed with at least one groove portion 511 and one convex portion 512, it is possible to effectively suppress the occurrence of uneven density in an image having a large area. For example, when the maximum width in the axial direction of the groove portion 511 is 40 μm and the maximum width in the axial direction of the convex portion 512 is 40 μm, dot-like latent images partitioned in a lattice shape with a pitch of 127.5 μm can be formed. Since the region includes both one groove portion 511 and one convex portion 512, it is possible to effectively suppress the occurrence of density unevenness in an image having a large area.

  In the present embodiment, the example in which the top surface 512a of the convex portion 512 surrounded by the two types of groove portions 511a and 511b is square has been described, but the present invention is not limited to this. FIG. 12 is a diagram illustrating a first modification of the developing roller. FIG. 13 is a diagram illustrating a second modification of the developing roller. FIG. 14 is a diagram illustrating a third modification of the developing roller.

  In the developing roller 510 of the first modified example, the top surface 512a of the convex portion 512 surrounded by the two types of groove portions 511 is a rhombus, and the groove portions so that one of the two diagonal lines of each rhombus is along the circumferential direction. Is formed. Also in the developing roller 510 of the first modified example, since the concave portion is formed by rolling as described above, the convex portion that is disposed with the concave portion interposed between the central portion 510a of the developing roller 510 and the die 900 is not in contact with it. The top surfaces 512a of 512, the top surface 512a of the convex portion 512 where the die 900 did not contact at the central portion 510a, and the both ends 510b not to be processed by rolling are a distance L from the axis C. Since it has been cut so as to be constant, it is located at an equal distance from the axis C.

  According to such a developing roller 510, since the groove portion 511 is formed so that one of the two diagonal lines of each rhombus is along the circumferential direction, one apex angle of the diagonal line along the circumferential direction. Therefore, two types of groove portions 511 are formed at the same angle on both end sides in the axial direction. For this reason, the toner particles T moved along the two types of groove portions 511 are moved in substantially the same way toward both ends in the axial direction, and it is possible to move the toner particles without unevenness. This is the same as when the surface 512a is square. In addition, when the longer diagonal line of the two diagonal lines of the convex part 512 whose top face 512a forms a rhombus is along the circumferential direction, the convex part 512 whose rhombic top face 512a is in the circumferential direction. Two apex angles positioned along the axis become acute angles, and two apex angles positioned along the axial direction become obtuse angles. For this reason, the toner particles can be configured to move more easily in the circumferential direction.

  Further, as shown in FIG. 13, when the shorter diagonal line of the two diagonal lines of the convex part 512 whose top surface 512a forms a rhombus is along the circumferential direction, the convex part whose top surface is a rhombus Two apex angles located along the circumferential direction are obtuse angles, and two apex angles located along the axial direction are acute angles. Also in the developing roller 510 of the second modified example, since the concave portion is formed by rolling as described above, the convex portion which is disposed with the concave portion interposed between the central portions 510a of the developing roller 510 and the die 900 is not in contact with it. The top surfaces 512a of 512, the top surface 512a of the convex portion 512 where the die 900 did not contact at the central portion 510a, and the both ends 510b not to be processed by rolling are a distance L from the axis C. Since it has been cut so as to be constant, it is located at an equal distance from the axis C. Therefore, the toner particles can be more easily moved in the axial direction, and the toner can be more dispersed throughout the developing roller 510.

  In the present embodiment, the example in which the two types of groove portions 511a and 511b are provided on the surface of the developing roller 510 has been described. However, as in the third modified example illustrated in FIG. Also in the developing roller 510 of the third modified example, since the concave portion is formed by rolling as described above, the convex portion that is arranged with the concave portion in the central portion 510a of the developing roller 510 and the die 900 is not in contact with it. The distance L from the axis C is constant between the surfaces of 512 and the surface of the convex part 512 where the die 900 did not contact at the center part 510a and the both end parts 510b not to be processed by rolling. Thus, it is located at an equal distance from the axis C. In this case, the toner particles T have the effect of being charged by rolling in a predetermined direction. However, there are two types of groove portions as a configuration for better charging and further dispersing the toner particles throughout the entire area of the developing roller 510. The developing roller 510 of the above embodiment having 511a and 511b has an excellent effect.

=== Other Embodiments ===
The image forming apparatus and the like according to the present invention have been described above based on the above embodiment. However, the above embodiment of the present invention is for facilitating understanding of the present invention and limits the present invention. is not. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  In the above embodiment, an example in which the printer includes a plurality of attaching / detaching portions has been described. However, a lid unit that can be closed by inserting a developing device to be attached to only one attaching / detaching portion is provided. You may be the structure provided. In the above-described embodiment, the image forming apparatus including the rotary developing device has been described as an example. However, the present invention is not limited to this. For example, the present invention can be applied to an image forming apparatus provided with a tandem developing device.

  In the above embodiment, the photoconductor as the image carrier has been described as a configuration in which the photosensitive layer is provided on the outer peripheral surface of the cylindrical conductive base material, but the present invention is not limited to this. For example, a so-called photosensitive belt configured by providing a photosensitive layer on the surface of a belt-like conductive substrate may be used.

=== Configuration of Image Forming System etc. ===
Next, an image forming system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 15 is an explanatory diagram showing an external configuration of the image forming system. The image forming system 700 includes a computer 702, a display device 704, a printer 10, an input device 708, and a reading device 710.

  In this embodiment, the computer 702 is housed in a mini-tower type housing, but is not limited thereto. The display device 704 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 10, the printer described above is used. In this embodiment, the input device 708 uses a keyboard 708A and a mouse 708B, but is not limited thereto. In this embodiment, the reading device 710 uses a flexible disk drive device 710A and a CD-ROM drive device 710B. However, the reading device 710 is not limited to this. Disk) etc. may be used.

  FIG. 16 is a block diagram showing a configuration of the image forming system shown in FIG. An internal memory 802 such as a RAM and an external memory such as a hard disk drive unit 804 are further provided in a housing in which the computer 702 is housed.

  In the above description, an example in which the printer 10 is connected to the computer 702, the display device 704, the input device 708, and the reading device 710 to configure the image forming system has been described. However, the present invention is not limited to this. Absent. For example, the image forming system may include the computer 702 and the printer 10, and the image forming system may not include any of the display device 704, the input device 708, and the reading device 710.

  For example, the printer 10 may have a part of each function or mechanism of the computer 702, the display device 704, the input device 708, and the reading device 710. As an example, the printer 10 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.

  The image forming system realized in this way is a system superior to the conventional system as a whole system.

FIG. 2 is a diagram illustrating main components constituting a printer. It is a figure for demonstrating the structure of the control unit with which the printer was equipped. It is a perspective view of a yellow developing device. It is sectional drawing which showed the main components of the yellow developing device. FIG. 6 is a perspective view showing a developing device with a developing roller removed. It is a conceptual diagram for demonstrating the surface shape of a developing roller. It is sectional drawing for demonstrating the cross section at the time of cut | disconnecting a developing roller by the plane which passes along an axis | shaft. It is a figure for demonstrating a mode that a developing roller is formed by rolling. It is a figure which shows the procedure in which a developing roller is formed. FIG. 6 is a diagram for explaining a state in which a regulating blade is in contact with a developing roller carrying toner particles. It is a figure for demonstrating the resolution in a screen and a latent image. It is a figure which shows the 1st modification of a developing roller. It is a figure which shows the 2nd modification of a developing roller. It is a figure which shows the 3rd modification of a developing roller. 1 is an explanatory diagram showing an external configuration of an image forming system. FIG. 16 is a block diagram illustrating a configuration of the image forming system illustrated in FIG. 15.

Explanation of symbols

10 printer, 20 photoconductor, 30 charging unit, 40 exposure unit,
50 Developer holding unit, 50a, 50b, 50c, 50d Detachable part,
50e central axis, 51 black developer, 52 magenta developer,
53 Cyan developer, 54 Yellow developer, 60 Primary transfer unit,
70 intermediate transfer body, 75 cleaning unit, 76 cleaning blade,
80 secondary transfer unit, 90 fixing unit, 92 paper feed tray,
94 paper feed roller, 95 display unit, 96 registration roller, 100 control unit,
101 main controller, 102 unit controller, 111 CPU,
112 interface, 113 image memory, 116 memory, 120 CPU,
509 Non-rolled processing developing roller, 510 developing roller, 510a central portion,
510b end (both ends), 510c step, 510d surface, 511 groove (concave),
511a One groove (recess), 511b The other groove (recess), 511c Bottom surface,
511d Inclined portion, 512 convex portion, 512a top surface, 513 flange,
513a Flange body, 513b shaft, 515 cylindrical member, 520 upper seal,
522 seal support sheet metal, 524 seal urging member, 527 end seal,
530 toner container, 530a first toner container, 530b second toner container,
540 housing, 542 upper housing part, 544 lower housing part,
545 partition wall, 550 toner supply roller, 550a roller section,
550b shaft body, 560 regulating blade, 560a rubber part, 560b rubber support part,
562 blade support sheet metal, 570 blade backing member, 572 opening,
700 image forming system, 702 computer, 704 display device,
708 input device, 708A keyboard, 708B mouse, 710 reader,
710A flexible disk drive device,
710B CD-ROM drive device,
802 internal memory, 804 hard disk drive unit,
900 dies, 900a blade, C axis, T toner (toner particles)

Claims (16)

A toner particle carrying roller having a central part having a concave part provided by a machining tool and a convex part having a surface that does not contact the machining tool, and both end parts not to be machined, for carrying toner particles ,as well as,
A layer thickness regulating member that is in contact with the central portion and the both ends of the toner particle carrying roller and regulates the layer thickness of the toner particles carried on the toner particle carrying roller;
Have
The latent image developed by the toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a grid-divided region,
The lattice can be formed at a plurality of pitches in the axial direction,
The developing device according to claim 1, wherein a pitch of the recesses in the axial direction is shorter than a longest pitch among a plurality of types of pitches in the lattice . The developing device according to claim 1,
The developing device is characterized in that the concave portions are arranged in an axial direction at an equal pitch and are formed in a spiral shape. The developing device according to claim 2,
2. The developing device according to claim 1, wherein the concave portion is formed in two types with different inclination angles with respect to the axial direction and the circumferential direction. The developing device according to any one of claims 1 to 3,
2. A developing device according to claim 1, wherein a distance from a top surface of the convex portion to a bottom surface of the concave portion is constant. The developing device according to claim 4,
A developing device characterized in that the distance from the top surface of the convex portion to the bottom surface of the concave portion is not more than twice the volume average particle diameter of the toner particles. The developing device according to any one of claims 3 to 5,
The developing device according to claim 2, wherein the two types of concave portions intersect each other to form a lattice shape. The developing device according to claim 6,
2. A developing device according to claim 1, wherein a top surface of the convex portion surrounded by the concave portion is a rhombus. The developing device according to claim 7,
2. The developing device according to claim 1, wherein the two types of the concave portions are formed so that one of two diagonal lines on the top surface of each convex portion is along the circumferential direction. The developing device according to claim 8, wherein
2. The developing device according to claim 1, wherein the convex portion has a longer diagonal line along the circumferential direction of the two diagonal lines. The developing device according to claim 6,
The developing device according to claim 1, wherein the top surface of the convex portion surrounded by the concave portion is square. The developing device according to any one of claims 1 to 10,
The developing device, wherein the convex portion has a surface for supporting the toner particles. The developing device according to any one of claims 1 to 11,
The developing device according to claim 1, wherein the carried toner particles are pressed by a plane of the layer thickness regulating member. It has a central part provided with a concave part provided by a machining tool and a convex part having a surface that does not contact the machining tool, and both end parts not to be machined, and spans the central part and the both end parts. A toner particle carrying roller in which the layer thickness of the toner particles carried by the abutted layer thickness regulating member is regulated ,
The latent image developed by the toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a grid-divided region,
The lattice can be formed at a plurality of pitches in the axial direction,
The toner particle carrying roller , wherein a pitch of the recesses in the axial direction is shorter than a longest pitch among a plurality of types of pitches in the lattice . A toner particle carrying roller having a central part having a concave part provided by a machining tool and a convex part having a surface that does not contact the machining tool, and both end parts not to be machined, for carrying toner particles ,as well as,
A layer thickness regulating member that is in contact with the central portion and the both ends of the toner particle carrying roller and regulates the layer thickness of the toner particles carried on the toner particle carrying roller;
An image forming apparatus for forming an image using a developing device having,
The latent image developed by the toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a grid-divided region,
The lattice can be formed at a plurality of pitches in the axial direction,
The pitch of the said recessed part in the said axial direction is shorter than the longest pitch among several types of pitches in the said grating | lattice, The image forming apparatus characterized by the above-mentioned . Computer and
Connected to the computer,
A toner particle carrying roller having a central part having a concave part provided by a machining tool and a convex part having a surface that does not contact the machining tool, and both end parts not to be machined, for carrying toner particles ,as well as,
A layer thickness regulating member that is in contact with the central portion and the both ends of the toner particle carrying roller and regulates the layer thickness of the toner particles carried on the toner particle carrying roller;
An image forming apparatus for forming an image using a developing device having
An image forming system comprising :
The latent image developed by the toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a grid-divided region,
The lattice can be formed at a plurality of pitches in the axial direction,
An image forming system , wherein a pitch of the recesses in the axial direction is shorter than a longest pitch among a plurality of types of pitches in the lattice . It has a central part provided with a concave part provided by a machining tool and a convex part having a surface that does not contact the machining tool, and both end parts not to be machined, and spans the central part and the both end parts. A toner particle carrying roller in which the layer thickness of the toner particles carried by the abutted layer thickness regulating member is regulated,
The latent image developed by the toner particles carried on the toner particle carrying roller has a dot-like latent image formed in a grid-divided region,
The lattice can be formed at a plurality of pitches in the axial direction,
The pitch of the recesses in the axial direction is a manufacturing method of a toner particle carrying roller shorter than the longest pitch among a plurality of types of pitches in the lattice,
Attaching flanges having shafts to both ends of a cylindrical member having a cylindrical shape;
Cutting the surface of the cylindrical member to be concentric with the shaft while rotating the cylindrical member to which the flange is attached;
While rotating two dies for forming two different types of spiral grooves arranged in parallel with each other so that the pitch is shorter than the longest pitch, and rotating the cut cylindrical member, The two dies are moved along the axial direction while leaving both ends not to be processed, and the die is pressed against the surface of the cylindrical member, so that the processing tool is recessed in the central portion in the axial direction. Forming a recessed portion provided and a convex portion having a surface that the processing tool does not contact; and
A method for producing a toner particle carrying roller, comprising:

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