JP4779660B2 - Image forming apparatus and image forming system - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming system.

  Image forming apparatuses such as laser beam printers are already well known. Such an image forming apparatus includes, for example, an image carrier for carrying a dot image latent image and the dot latent image carried on the image carrier by a developer carried on the surface thereof as a developer image. And a rotatable developer carrying roller for visualization. The image carrier is rotatable about a central axis, and the developer carrying roller faces the image carrier so that its axial direction is parallel to the axial direction of the image carrier.

Then, when an image signal or the like is transmitted from an external device such as a host computer, the image forming apparatus positions the developing device at a developing position facing the image carrier, and develops the latent image carried on the image carrier. Development is performed with toner particles in the apparatus to form a toner image, the toner image is transferred to a medium, and finally an image is formed on the medium.
JP-A-1-102486 JP 2000-228728 A

  In the developer carrying roller, a spiral groove portion having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at an equal pitch in the axial direction is provided on the surface. There is something. Then, when the dot-like latent image is visualized as a developer image by the developer carried on the developer carrying roller provided with the groove, density unevenness (for example, development carried on the groove) in the developer image. The density unevenness due to the amount of the developer being larger than the amount of the developer carried on the portion other than the groove portion may occur periodically.

  A plurality of partitioned regions in which the dot-like latent images are arranged in a row along a direction intersecting a predetermined intersection angle with respect to the axial direction of the central axis of the image carrier (hereinafter also referred to as an intersection direction); When carried on each, a plurality of dot image latent images carried are also formed along the intersecting direction.

  Under such circumstances, depending on the relative positions of the groove and the plurality of partitioned regions, density unevenness due to the groove may be conspicuous in the visualized developer image. For example, when the image carrier and the developer carrying roller rotate for visualizing the dot-like latent image as a developer image, if the relative positions of the plurality of divided regions with respect to the groove portion coincide, The dot-like latent image carried in each of the regions may be visualized as a developer image by the developer carried on the same portion of the groove. In such a case, there is a possibility that density unevenness due to the groove portion is easily noticeable in the visualized developer image.

  The present invention has been made in view of such problems, and an object of the present invention is to realize an image forming apparatus and an image forming system capable of suppressing density unevenness from becoming conspicuous.

In order to solve the above-mentioned problem, the main present invention is: (a) an image carrier that is rotatable about a central axis, and a predetermined surface with respect to the axial direction of the central axis on the surface of the image carrier. An image carrier that carries a dot-like latent image in each of a plurality of partitioned regions arranged in rows along a direction intersecting at an intersection angle; and (b1) the axial direction of which is the axial direction of the image carrier. A rotatable developer that faces the image carrier so as to be parallel and visualizes the dot-like latent image carried on the image carrier as a developer image by a developer carried on the surface of the image carrier. A carrying roller comprising: (b2) a helical groove on the surface having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at equal pitches in the axial direction. possess a roller, the (c), (d) Examples developing carrying roller, four color development Each of the four developer-carrying rollers, and the groove portions of the four developer-carrying rollers have the same inclination angle, and (d) the plurality of divided regions are divided into divided region groups. As the partitioned area groups, dot-like latent images visualized as developer images by each of the four color developers are respectively provided with four partitioned area groups, and each of the four partitioned area groups The sizes of the crossing angles are different from each other, and (e) the size of the tangent of the inclination angle of the groove portion of the four developer-carrying rollers is set as the moving speed of the surface of each developer-carrying roller. ratio moving velocity of the surface of the carrier, in divided value is an image forming apparatus according to claim with any different Rukoto the magnitude of the angle of intersection tangent of the four divided areas group.

  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) An image carrier that is rotatable about a central axis, and is arranged in a row on the surface of the image carrier along a direction that intersects the axial direction of the central axis at a predetermined intersection angle. An image carrier that carries a dot-like latent image in each of the plurality of partitioned regions, and (b1) faces the image carrier so that its axial direction is parallel to the axial direction of the image carrier, A rotatable developer-carrying roller for visualizing the dot-like latent image carried on the image carrier by a developer carried on the surface as a developer image, (b2) on the surface; A spiral groove portion having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at an equal pitch in the axial direction, and the tangent of the inclination angle is determined by the developer carrying roller. Divided by the ratio of the moving speed of the surface of the image to the moving speed of the surface of the image carrier. But the size of the crossing angle of the tangent and the different developer carrying roller, the image forming apparatus characterized by having (c).
In such a case, the dot-like latent images carried on each of the plurality of partitioned regions arranged in a line along the intersecting direction are carried on the same part of the groove part (or the same part other than the groove part). The developer can be prevented from being visualized as a developer image. Therefore, according to the above-described image forming apparatus, it is possible to suppress the density unevenness from becoming conspicuous.

  Further, in this image forming apparatus, the developer is a first developer, the plurality of partitioned areas form a partitioned area group, and the partitioned area group is developed by the first developer. A first divided region group carrying a dot image latent image visualized as an image, and a dot image latent image visualized as a developer image by a second developer whose color is different from the color of the first developer. A second divided region group to be carried, wherein the tangent of the inclination angle is divided by the ratio of the moving speed of the surface of the developer carrying roller to the moving speed of the surface of the image carrier. The value may be different from the magnitude of the tangent of the intersection angle of the first partition area group and the magnitude of the tangent of the intersection angle of the second partition area group.

  Further, in this image forming apparatus, the image forming apparatus is capable of forming a color image with four color developers including the first developer and the second developer, and the partitioned region group includes: The dot-like latent images visualized as developer images by each of the four color developers are each divided into four divided region groups, and the tangent of the inclination angle is set to the value of the developer carrying roller. A value obtained by dividing the surface moving speed by the ratio of the surface moving speed of the image carrier may be different from the magnitude of the tangent of the intersecting angles of the four partitioned area groups.

The image forming apparatus may further include four developer-carrying rollers that carry each of the four colors of developer, each having a different intersection angle between the four divided region groups. The inclination angles of the groove portions of the four developer carrying rollers are the same, and the tangent of the inclination angle of the groove portions of the four developer carrying rollers is set to be different for each developer carrying roller. The value obtained by dividing the surface moving speed by the ratio of the surface moving speed of the image carrier may be different from any of the tangents of the intersecting angles of the four divided area groups.
In this case, since the inclination angles of the grooves of the four developer carrying rollers are the same, the productivity of the developer carrying roller is improved. On the other hand, since the value is different from any of the tangents of the intersection angles of the four divided area groups, it is possible to suppress the density unevenness from being easily noticeable.

Further, in this image forming apparatus, the developer is a first developer, the developer carrying roller is a first developer carrying roller, and includes the groove portion, and the color of the developer carrying roller is the first developer. A second developer carrying roller carrying a second developer different from the color of the developer, and the inclination angle of the groove of the second developer carrying roller is greater than that of the first developer carrying roller. It may be different from the inclination angle of the groove.
In such a case, the uneven density caused by the groove portion of the first developer carrying roller and the uneven shade caused by the groove portion of the second developer carrying roller can be suppressed, so that the density unevenness is easily noticeable. Can be effectively suppressed.

  Further, in this image forming apparatus, the plurality of partitioned regions form a partitioned region group, and the partitioned region group carries a dot image latent image that is visualized as a developer image by the first developer. A first divided area group, and a second divided area group on which a dot image latent image visualized as a developer image by the second developer is carried, and an inclination angle of the groove portion of the second developer carrying roller The value obtained by dividing the size of the tangent by the ratio of the moving speed of the surface of the second developer carrying roller to the moving speed of the surface of the image carrier is the intersection of the first divided area groups. It may be different from the magnitude of the tangent of the angle.

Further, the image forming apparatus is capable of forming a color image with four color developers including the first developer and the second developer, and the first developer carrying A roller and a second developer carrying roller, and each of the four developer carrying rollers carrying each of the four colors of developer, and a large inclination angle of the groove portion of the four developer carrying rollers. Each may be different.
In such a case, since it is possible to suppress the uneven density due to the grooves of the four developer-carrying rollers from overlapping, it is possible to effectively prevent the uneven density from becoming conspicuous.

Further, the image forming apparatus is capable of forming a color image with four color developers including the first developer and the second developer, and the first developer carrying A roller and the second developer carrying roller, and having four developer carrying rollers for carrying each of the four color developers, and two developer carrying rollers out of the four developer carrying rollers It is good also as the magnitude | size of the inclination angle of the said groove part of a roller being the same.
For example, when the inclination angles of the groove portions of the four developer carrying rollers are the same, a developer carrying roller having a large inclination angle is generated, and the developer carrying roller may not carry the developer appropriately. . On the other hand, for example, by making the inclination angles of the groove portions of the two color developer carrying rollers that are less likely to cause unevenness in density to occur, it is possible to prevent the developer carrying roller having an increased inclination angle of the groove portions.

  Further, in this image forming apparatus, the divided area groups are four divided area groups on which dot-like latent images visualized as developer images by the developers of the four colors are respectively supported. The sizes of the intersecting angles of the four divided region groups are different from each other, and the size of the tangent of the inclination angle of the groove portion of the four developer-carrying rollers is determined by the moving speed of the surface of each developer-carrying roller. Each of the values divided by the ratio to the moving speed of the surface of the image carrier may be different from any of the tangent magnitudes of the intersecting angles of the four divided area groups.

Further, in this image forming apparatus, the divided area groups are four divided area groups on which dot-like latent images visualized as developer images by the developers of the four colors are respectively supported. The sizes of the crossing angles of the four partition region groups may be the same.
In such a case, since the size of the crossing angle of the four partition region groups is the same, it is possible to realize simple control compared to the case where the size of the crossing angle of the four partition region groups is different. Become.

In the image forming apparatus, the developer carrying roller may have a cylindrical portion having the surface, and the cylindrical portion may be made of a single material.
In such a case, the developer carrying roller described above can be easily manufactured.

Also, in this image forming apparatus, a developer layer carried on the developer carrying roller in contact with the developer carrying roller from one end to the other end in the axial direction of the developer carrying roller. A layer thickness regulating member for regulating the thickness may be provided, and the layer thickness regulating member may regulate the layer thickness by contacting a flat surface of the layer thickness regulating member with the developer carrying roller. .
In such a case, it is possible to suppress density unevenness due to the variation in the layer thickness by regulating the layer thickness of the developer.

In the image forming apparatus, the developer may be granular, and the depth of the groove may be not more than twice the volume average particle diameter of the developer.
In such a case, since most of the developer located between the developer carrying roller and the layer thickness regulating member in the groove portion contacts at least one of the developer carrying roller and the layer thickness regulating member, The chargeability of the developer becomes appropriate.

  Further, in this image forming apparatus, the developer carrying roller includes the groove portion and the convex portion on a surface thereof, and both the groove portion and the convex portion are carrying portions for carrying the developer. It may be there.

(A) an image carrier that can rotate about a central axis, and is arranged in a row along a direction intersecting the axial direction of the central axis at a predetermined intersection angle on the surface of the image carrier. An image carrier that carries a dot-like latent image in each of a plurality of partitioned regions disposed on the surface of the image carrier, and (b1) faces the image carrier so that its axial direction is parallel to the axial direction of the image carrier. A rotatable developer carrying roller for visualizing the dot-like latent image carried on the image carrier by a developer carried on the surface thereof as a developer image, (b2) A spiral groove portion having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at an equal pitch in the axial direction, and the tangent of the inclination angle is determined by the developer. The ratio of the moving speed of the surface of the carrying roller to the moving speed of the surface of the image carrier. (C), (d) the developer is a first developer, and the plurality of partition areas are defined as partition sections. Forming a region group, and the partition region group includes a first partition region group carrying a dot image latent image visualized as a developer image by the first developer, and a color of the first partition region group. A second divided region group on which a latent image of a dot image that is visualized as a developer image by a second developer different from that of the developer carrying roller, and the tangent of the inclination angle is moved on the surface of the developer carrying roller. A value obtained by dividing the speed by the ratio of the moving speed of the surface of the image carrier to the tangent of the intersection angle of the first partition region group and the intersection of the second partition region group Unlike the tangent of the angle, (e) the image forming apparatus includes the first developer and the tangent. A color image can be formed with four color developers including the second developer, and the partitioned region group is a dot-like latent image visualized as a developer image by each of the four color developers. 4 divided area groups each carried, and the magnitude of the tangent of the tilt angle is divided by the ratio of the moving speed of the surface of the developer carrying roller to the moving speed of the surface of the image carrier. (F) The sizes of the intersection angles of the four partition region groups are different from each other, and the values of the four color developers are different from each other. Each of the four developer-carrying rollers carrying the same, and the inclination angles of the groove portions of the four developer-carrying rollers are the same, and the inclination of the groove portions of the four developer-carrying rollers is the same. Each developer carrying the size of the tangent of the angle A value obtained by dividing the moving speed of the surface of the roller by the ratio of the moving speed of the surface of the image carrier to the moving speed of the surface of the image carrier is different from any of the tangents of the intersecting angles of the four divided area groups. ) The developer carrying roller has a cylindrical portion having the surface, and the cylindrical portion is made of a single material, and (h) extends from one end to the other end in the axial direction of the developer carrying roller. A layer thickness regulating member that contacts the developer carrying roller and regulates the layer thickness of the developer carried on the developer carrying roller, and the layer thickness regulating member includes: The layer having a flat surface is in contact with the developer carrying roller to regulate the layer thickness. (I) The developer has a granular shape, and the depth of the groove is 2 of the volume average particle size of the developer. (J) The developer carrying roller includes the groove and the convex on the surface thereof. The groove and the protrusion are both, an image forming apparatus wherein the developer is a carrier part for carrying.
According to such an image forming apparatus, an effect capable of suppressing the density unevenness from being conspicuous is effectively produced.

(A) an image carrier that can rotate about a central axis, and is arranged in a row along a direction intersecting the axial direction of the central axis at a predetermined intersection angle on the surface of the image carrier. An image carrier that carries a dot-like latent image in each of a plurality of partitioned regions disposed on the surface of the image carrier, and (b1) faces the image carrier so that its axial direction is parallel to the axial direction of the image carrier. A rotatable developer carrying roller for visualizing the dot-like latent image carried on the image carrier by a developer carried on the surface thereof as a developer image, (b2) A spiral groove portion having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at an equal pitch in the axial direction, and the tangent of the inclination angle is determined by the developer. The ratio of the moving speed of the surface of the carrying roller to the moving speed of the surface of the image carrier. (C), (d) the developer is a first developer, and the developer carrying roller is a first developer having a value different from the tangent of the crossing angle. A second developer carrying roller, the second developer carrying roller having the groove and having a second developer having a color different from that of the first developer. (E) the plurality of partition regions form a partition region group, and the partition region includes a partition region group, wherein the groove portion has a tilt angle size different from that of the groove portion of the first developer carrying roller. The group carries a first divided area group on which a dot image latent image visualized as a developer image by the first developer is carried, and a dot image latent image visualized as a developer image by the second developer. A second divided region group, in front of the second developer carrying roller. A value obtained by dividing the tangent of the inclination angle of the groove portion by the ratio of the moving speed of the surface of the second developer carrying roller to the moving speed of the surface of the image carrier is the first partition region. Unlike the tangent of the intersection angle of the group, (f) the image forming apparatus can form a color image with four color developers including the first developer and the second developer, The first developer carrying roller and the second developer carrying roller, the four developer carrying rollers carrying each of the four color developers, and the groove portions of the four developer carrying rollers. (G) The divided area group includes four divided areas on which dot-like latent images visualized as developer images by the developers of the four colors are respectively carried. A large intersection angle of the four partition region groups. The sizes are different, and the tangent of the inclination angle of the groove portions of the four developer carrying rollers is defined as the moving speed of the surface of each developer carrying roller. Each of the values divided by the ratio to the height is different from any of the tangents of the intersecting angles of the four divided area groups, and (h) the developer carrying roller has a cylindrical portion provided with the surface. And the cylindrical portion is made of a single material. (I) The developer carrying roller is in contact with the developer carrying roller from one end to the other end in the axial direction of the developer carrying roller. A layer thickness regulating member for regulating the layer thickness of the developer carried on the layer, wherein the layer thickness regulating member is configured such that a plane of the layer thickness regulating member comes into contact with the developer carrying roller, whereby the layer (J) the developer has a granular shape, and the groove portion The volume average particle diameter of the developer is not more than twice, (k) the developer carrying roller comprises the groove and the convex on the surface, both the groove and the convex, An image forming apparatus, wherein the image forming apparatus is a carrying portion for carrying the developer.
According to such an image forming apparatus, an effect capable of suppressing the density unevenness from being conspicuous is effectively produced.

(A) a computer; and (B) an image forming apparatus that can be connected to the computer, and (a) an image carrier that can rotate about a central axis, on the surface of the image carrier. (B1) an image carrier that carries a dot-like latent image in each of a plurality of partitioned regions arranged in a row along a direction that intersects the axial direction of the central axis at a predetermined crossing angle. The dot-shaped latent image carried on the image carrier is developed with the developer carried on the surface of the image carrier so that its axial direction is parallel to the axial direction of the image carrier. A rotatable developer carrying roller for visualizing as a developer image, (b2) formed on the surface at a predetermined inclination angle with respect to the axial direction of the developer carrying roller at an equal pitch in the axial direction A spiral groove portion, and the tangent of the inclination angle, A developer carrying roller in which a value obtained by dividing the moving speed of the surface of the developer carrying roller by the ratio of the moving speed of the surface of the image carrier to the moving speed of the surface of the image carrier is different from the tangent of the crossing angle; An image forming apparatus comprising (C).
According to such an image forming system, it is possible to prevent the density unevenness from becoming conspicuous.

=== Example of Overall Configuration of Image Forming System ===
The outline of the image forming system 700 will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram showing an external configuration of the image forming system 700. FIG. 2 is a block diagram showing a part of the configuration of the image forming system 700 shown in FIG. The image forming system 700 includes a laser beam printer (hereinafter also referred to as a printer) 10 as an “image forming apparatus” and a computer 702 capable of communicating with the printer 10.

  The computer 702 includes a display device 704 for displaying information such as a cathode ray tube (CRT), a liquid crystal display device, a plasma display, an input device 708 such as a keyboard 708A and a mouse 708B, and an FD (flexible drive). Reading device 710 such as device 710A, CD-ROM drive device 710B, MO (Magneto Optical) disk drive device (not shown), DVD (Digital Versatile Disk) device (not shown), and internal memory such as RAM (not shown) And an external memory (not shown) such as a hard disk drive unit. The computer 702 is housed in a mini-tower type housing in this embodiment, but is not limited to this.

  The computer 702 includes an operating system, an application program 795 that operates under the operating system, and a printer driver 796 that is an example of a control program. The printer driver 796 includes an image processing unit 797, a display interface unit 801, an input interface unit 803, and a user interface processing unit 805.

  The application program 795 is a program on the computer 702 for causing the printer 10 to perform image formation. Image data AD on the application program is sent to the printer driver 796 in accordance with an image formation execution command from the application program 795.

  The image processing unit 797 receives the image data AD that can be interpreted by the application program 795, converts the image data AD into image data PD that can be interpreted by the printer 10, and sends the converted image data PD to the printer 10 together with various control signals COM. It has a function to do. That is, the image processing unit 797 of the printer driver 796 instructs the printer 10 to execute image formation after performing the above-described image processing. In order to realize the function, the image processing unit 797 performs resolution conversion, color component conversion, and the like, for example. The image processing unit 797 converts the image data AD into image data PD based on a mesh screen (described later) determined for each color.

  The display interface unit 801 has a function of displaying various user interface windows related to image formation on the display device 704. The input interface unit 803 has a function of receiving input information input by the user using the input device 708 on the user interface window.

  The user interface processing unit 805 has a function of providing an interface between the display interface unit 801 or the input interface unit 803 and the printer 10. For example, the user interface processing unit 805 receives the input information from the input interface unit 803 and interprets the input information. Then, various control signals COM are sent to the printer 10 and the image processing unit 797. Further, it interprets various control signals COM received from the printer 10 and sends information related to display to the display interface unit 801.

  Note that the printer driver 796 included in the computer 702 is supplied in a form recorded on a computer-readable recording medium. Such recording media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter on which codes such as bar codes are printed, computer internal storage devices (such as RAM and ROM). A variety of computer-readable media such as a memory) and an external storage device can be used. It is also possible to download such a computer program to the computer 702 via the Internet.

=== Overview of Image Forming Apparatus ===
Next, the outline of the printer 10 will be described with reference to FIG. FIG. 3 is a diagram showing main components constituting the printer 10. In FIG. 3, 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 Example of Printer 10 >>>
As shown in FIG. 3, the printer 10 according to the present embodiment includes a charging unit 30, an exposure unit 40, a YMCK developing unit 50, a primary unit along the rotation direction of the photoconductor 20 as an example of an “image carrier”. The image forming apparatus includes a transfer unit 60, an intermediate transfer member 70, and a cleaning unit 75. Further, a secondary transfer unit 80, a fixing unit 90, a display unit 95 including a liquid crystal panel that serves as a notification unit for a user, and these units are provided. It has a control unit 100 that controls and 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 photoconductor 20 carries a dot-like latent image on the surface of the photoconductor 20 based on the mesh screen determined by the image processing unit 797. Note that how the photoconductor 20 carries a dot-like latent image will be described later.

  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, a polygon mirror, an F-θ lens, and the like, and charges the modulated laser based on an image signal input from a host computer (not shown) such as a personal computer or a word processor. The irradiated photoconductor 20 is irradiated.

  The YMCK developing unit 50 converts the latent image formed on the photoreceptor 20 into toner T as an example of “developer” stored in the “developing device”, that is, black (K) stored in the black developing device 51. ) Development using toner, magenta (M) toner contained in the magenta developing device 52, cyan (C) toner contained in the cyan developing device 53, and yellow (Y) toner contained in the yellow developing device 54 It is a device for doing.

  The YMCK developing unit 50 can move the positions of the four developing devices 51, 52, 53, 54 by rotating with the four developing devices 51, 52, 53, 54 mounted. Yes. That is, the YMCK developing unit 50 holds the four developing devices 51, 52, 53, 54 by four holding portions 55a, 55b, 55c, 55d, and the four developing devices 51, 52, 53, 54 is rotatable around the central axis 50a while maintaining the relative position thereof. Each time image formation for one page is completed, it is selectively opposed to the photoconductor 20 and is formed on the photoconductor 20 with the toner T contained in each developing device 51, 52, 53, 54. The latent images are sequentially developed. Each of the four developing devices 51, 52, 53, 54 described above is detachable from the holding portion of the YMCK developing unit 50. 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 body 70 is an endless belt in which an aluminum vapor deposition layer is provided on the surface of a PET film and a semiconductive paint is formed on the surface layer and laminated. The intermediate transfer body 70 is driven to rotate at substantially the same peripheral speed as the photoconductor 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 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 medium 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. 4, the control unit 100 includes a main controller 101 and a unit controller 102. An image signal and a control signal are input to the main controller 101, and a command based on the image signal and the control signal is received. A unit controller 102 controls each of the units and forms an image.

<<< Example of Operation of Printer 10 >>>
Next, the operation of the printer 10 configured as described above will be described. First, when an image signal and a control signal from a host computer (not shown) are input to the main controller 101 of the printer 10 via the interface (I / F) 112, the unit controller 102 based on a command from the main controller 101. The photosensitive member 20, the developing roller, and the intermediate transfer member 70 are rotated by the control. The photoconductor 20 is sequentially charged by the charging unit 30 at the charging position while rotating.

  The charged area of the photoconductor 20 reaches an 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 in the area by the exposure unit 40. . In the YMCK developing unit 50, a yellow developing device 54 that contains yellow (Y) toner is located 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 T is applied to the primary transfer unit 60. During this time, the photosensitive member 20 and the intermediate transfer member 70 are in contact with each other, and the secondary transfer unit 80 is separated from the intermediate transfer member 70.

  The above processing is sequentially executed for each developing device for the second color, the third color, and the fourth color, so that four color toner images corresponding to the respective image signals are transferred to the intermediate transfer member 70. It is transcribed and superimposed. 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 the medium by the secondary transfer unit 80. The medium 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 medium is heated and pressed by the fixing unit 90 and fused to the medium. On the other hand, after the primary transfer position has passed, the photosensitive member 20 is scraped off by the cleaning blade 76 supported by the cleaning unit 75 and the toner T adhering to the surface thereof is charged to form the next latent image. Prepare for. The toner T thus scraped off is collected by a residual toner collecting unit provided in the cleaning unit 75.

=== Overview of Control Unit ===
Next, the configuration of the control unit 100 will be described with reference to FIG. FIG. 4 is a block diagram showing a control unit of the printer 10 of FIG.

  The main controller 101 of the control unit 100 is connected to a host computer via an interface 112 and includes an image memory 113 for storing image signals input from the host computer. The unit controller 102 is electrically connected to each unit (charging unit 30, exposure unit 40, YMCK developing unit 50, primary transfer unit 60, cleaning unit 75, secondary transfer unit 80, fixing unit 90, display unit 95) of the apparatus main body. Each unit is controlled based on a signal input from the main controller 101 while detecting a state of each unit by receiving a signal from a sensor included in the unit.

=== About the mesh screen ===
The printer 10 forms a halftone image by causing the developing device to develop the dot-like latent image carried on the photoconductor 20 based on the image data PD sent from the image processing unit 797. Here, halftone dots are large and small dots that are regularly arranged in a shaded image with a size that is not obvious to the naked eye. The printer 10 expresses the shade of an image by the size of halftone dots. it can. Then, the image processing unit 797 converts the image data PD from the image data AD based on a so-called mesh screen (hereinafter also simply referred to as a screen) so that halftone dots are formed.

  This screen will be described with reference to FIGS. 5A to 5D. 5A is a schematic diagram showing a black screen, FIG. 5B is a schematic diagram showing a magenta screen, FIG. 5C is a schematic diagram showing a cyan screen, and FIG. 5D shows a yellow screen. It is a schematic diagram. 5A to 5D, arrows indicate a direction corresponding to the axial direction of the photoconductor 20 (hereinafter simply referred to as the axial direction) and a direction corresponding to the circumferential direction of the photoconductor 20 (hereinafter simply referred to as the circumferential direction). Called the direction).

  In the screen, as shown in FIG. 5A and the like, a large number of meshes (□ shown in FIG. 5A and the like) are configured by the first and second lines orthogonal to each other. A halftone dot can be formed by the photosensitive member 20 carrying a dot-like latent image (indicated by a black circle in FIG. 5A) on each halftone dot. The dot-shaped latent image is carried on the photoconductor 20 so that the center thereof is located at the center of the mesh.

  A screen is provided for each color, that is, a black screen shown in FIG. 5A, a magenta screen shown in FIG. 5B, a cyan screen shown in FIG. 5C, and a yellow screen shown in FIG. 5D. The photoreceptor 20 uses a black screen to generate a black dot latent image, a magenta screen to use a magenta dot latent image, a cyan screen to use a cyan dot latent image, and a yellow screen to use a yellow screen. Each of the dot-like latent images is carried.

  Further, the mesh size of the above four screens is the same, but the arrangement state of the first line and the second line of each screen is different. That is, in the black screen, the first line is parallel to the circumferential direction (in other words, the first line is orthogonal to the axial direction), and the second line is parallel to the axial direction. On the other hand, in the magenta screen, the cyan screen, and the yellow screen, the first line and the second line are inclined with respect to the axial direction and the circumferential direction. Here, if the inclination angle with respect to the axial direction of the first line is called a screen angle, the screen angle of the black screen is 90 degrees, the screen angle of the magenta screen is 20 degrees, and the screen angle of the cyan screen is 50 degrees. The screen angle of the yellow screen is 70 degrees.

  The “plurality of divided areas” arranged in a row along the direction intersecting with the axial direction of the central axis of the photoconductor 20 at a predetermined intersecting angle q (hereinafter also referred to as the intersecting direction) is a black screen. Is a mesh surrounded by an ellipse C1 in FIG. 5A (hereinafter also referred to as a partitioned area row C1), and in the magenta screen, is a mesh surrounded by an ellipse C2 in FIG. 5B (hereinafter also referred to as a partitioned area row C2). In the cyan screen, the mesh is surrounded by an ellipse C3 in FIG. 5C (hereinafter also referred to as a partitioned area row C3), and in the yellow screen, the mesh is surrounded by an ellipse C4 in FIG. 5D (hereinafter also referred to as a partitioned area row C4). Call).

  The black screen partition region column C1, the magenta screen partition region column C2, the cyan screen partition region column C3, and the yellow screen partition region column C4 are arranged along the first line, respectively. For this reason, the size of the intersection angle q of the partition region row C1 is the same as the screen angle of the black screen (that is, 90 degrees), and the size of the intersection angle q of the partition region row C2 is the magenta screen. The size of the screen angle of the cyan screen (that is, 20 degrees) is the same, and the size of the intersection angle q of the partition region row C3 is the same as the screen angle of the cyan screen (that is, 50 degrees). The size of the intersection angle q of the region column C4 is the same as the size of the screen angle of the yellow screen (that is, 70 degrees).

  As described above, the size of the intersection angle q of the partition region row C1 of the black screen is 90 degrees, the size of the intersection angle q of the partition region row C2 of the magenta screen is 20 degrees, and the partition region row C3 of the cyan screen Since the size of the crossing angle q is 50 degrees and the size of the crossing angle q of the partition area column C4 of the yellow screen is 70 degrees, the size of the crossing angle q of each partitioning area column of the four screens is respectively Different.

=== Overview of Developing Device ===
Next, a configuration example and an operation example of the developing device will be described with reference to FIGS. 6 and 7. FIG. 6 is a conceptual diagram of the developing device. FIG. 7 is a cross-sectional view showing the main components of the developing device. Note that the cross-sectional view shown in FIG. 7 represents a cross-section obtained by cutting the developing device along a plane perpendicular to the longitudinal direction shown in FIG. In FIG. 7, the vertical direction is indicated by arrows as in FIG. 6. For example, the central axis of the developing roller 510 is below the central axis of the photoconductor 20. Further, in FIG. 7, 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 YMCK developing 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 a yellow ( Y) Although a yellow developing device 54 containing toner is provided, the configuration of each developing device is the same, so the yellow developing device 54 will be described below.

<<< Example of configuration of developing device >>>
The yellow developing device 54 includes a developing roller 510 as an example of a “developer carrying roller”, an upper seal 520, a toner container 530, a housing 540, a toner supply roller 550, and a regulating blade 560 as an example of a “layer thickness regulating member”. Etc.

  The developing roller 510 is carried on the photoconductor 20 with toner carried on the surface of the developing roller 510 in a state facing the photoconductor 20 so that the axial direction thereof is parallel to the axial direction of the photoconductor 20. The dotted latent image is visualized as a toner image. The developing roller 510 is a member made of an aluminum alloy, an iron alloy, or the like. Further, the developing roller 510 has a convex portion 519 and a concave portion 518 on the surface thereof. The surface shape of the developing roller 510 will be described in detail later.

  Further, as shown in FIG. 6, the developing roller 510 is supported at both ends in the longitudinal direction of the developing device (the axial direction of the developing roller 510), and is rotatable about the central axis. As shown in FIG. 7, the developing roller 510 rotates in a direction (counterclockwise in FIG. 7) opposite to the rotation direction of the photoconductor 20 (clockwise in FIG. 7). The central axis is below the central axis of the photoconductor 20. The moving speed (linear velocity) of the surface of the developing roller 510 is different from the moving speed (linear velocity) of the surface of the photoconductor 20, and the moving speed of the surface of the developing roller 510 is This is 1.4 times the moving speed of the surface of the photoconductor 20.

  Further, a gap exists 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 housing 540 is manufactured by welding a plurality of integrally formed resin housing parts, that is, the upper housing part 542 and the lower housing part 544, and in order to accommodate the toner T therein. The toner container 530 is formed. The toner containing body 530 has two toner containing portions, that is, a first toner containing portion 530a and a second toner, by a partition wall 545 for separating the toner T projected inwardly (in the vertical direction in FIG. 7) 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 are in communication, and the movement of the toner T is restricted by the partition wall 545 in the state shown in FIG. However, when the YMCK developing unit 50 rotates, the toner accommodated in the first toner accommodating portion 530a and the second toner accommodating portion 530b is once collected on the upper communicating side of the developing position. When returning to the state shown in FIG. 7, the toners are mixed and returned to the first toner storage portion 530a and the second toner storage portion 530b. That is, when the YMCK developing unit 50 rotates, the toner T in the developing device is appropriately agitated.

  For this reason, in this embodiment, the toner container 530 is not provided with a stirring member, but a stirring member for stirring the toner T stored in the toner container 530 may be provided. Further, as shown in FIG. 7, the housing 540 (that is, the first toner storage portion 530 a) has an opening 572 in the lower portion, and the developing roller 510 is provided so as to face the opening 572.

  The toner supply roller 550 is provided in the first toner storage portion 530a described above, supplies the toner T stored in the first toner storage portion 530a to the development roller 510, and remains on the development roller 510 after development. The toner T is peeled off from the developing roller 510. The toner supply roller 550 is made of polyurethane foam or the like, and is in contact with the developing roller 510 in an elastically deformed state. The toner supply roller 550 is disposed below the first toner storage portion 530a, and the toner T stored in the first toner storage portion 530a is transferred by the toner supply roller 550 below the first toner storage portion 530a. Supplied to the developing roller 510. The toner supply roller 550 is rotatable about a central axis, and the central axis is below the rotation central axis of the developing roller 510. Further, the toner supply roller 550 rotates in a direction (clockwise in FIG. 7) opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 7).

  The upper seal 520 is in contact with the developing roller 510 along the axial direction thereof, allows the toner T remaining on the developing roller 510 after passing through the developing position to move into the housing 540, and the housing 540. The movement of the toner T inside the housing 540 is restricted. The upper seal 520 is a seal made of a polyethylene film or the like. The upper seal 520 is supported by an upper seal support portion 526a of a holder 526, which will be described later, and is provided such that its longitudinal direction is along the axial direction of the developing roller 510. The contact position where the upper seal 520 contacts the developing roller 510 is above the central axis of the developing roller 510.

  Further, a malt is provided between the surface of the upper seal 520 opposite to the contact surface 520b that contacts the developing roller 510 (this surface is also referred to as the opposite surface 520c) and the upper seal support portion 526a. An upper seal urging member 524 made of an elastic body such as a plane is provided in a compressed state. The upper seal urging member 524 presses the upper seal 520 against the developing roller 510 by urging the upper seal 520 toward the developing roller 510 with the urging force.

  The regulating blade 560 abuts against the developing roller 510 at the abutting portion 562a from one end to the other end in the axial direction of the developing roller 510 to regulate the layer thickness of the toner T carried on the developing roller 510, In addition, a charge is applied to the toner T carried on the developing roller 510. As shown in FIG. 7, the regulation blade 560 includes a rubber part 562 and a rubber support part 564.

  The rubber part 562 is made of silicon rubber, urethane rubber, or the like, and is in contact with the developing roller 510. The rubber support portion 564 includes a thin plate 564a and a thin plate support portion 564b, and supports the rubber portion 562 at one end portion 564d in the short direction (that is, the end portion on the thin plate 564a side). The thin plate 564a is made of phosphor bronze, stainless steel or the like and has a spring property. The thin plate 564a supports the rubber part 562 and presses the rubber part 562 against the developing roller 510 by the biasing force. The thin plate support portion 564b is a metal sheet metal disposed on the other end 564e in the short side direction of the rubber support portion 564, and the thin plate support portion 564b is a side of the thin plate 564a that supports the rubber portion 562. It is attached to the said thin plate 564a in the state which supported the edge on the opposite side.

  The end of the regulating blade 560 opposite to the thin plate support portion 564b side, that is, the tip 560a is not in contact with the developing roller 510, and is a portion separated from the tip 560a by a predetermined distance (that is, the contact portion 562a). ) Is in contact with the developing roller 510 with a width. That is, the regulating blade 560 is not in contact with the developing roller 510 at the edge, but in contact with the belly, and the plane (specifically, the plane of the rubber portion 562) of the regulating blade 560 is the developing roller. The layer thickness is regulated by abutting 510. Further, the regulating blade 560 is disposed so that its tip 560a faces the upstream side in the rotation direction of the developing roller 510, and is in contact with a so-called counter. 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. Further, the regulation blade 560 exhibits a function of preventing leakage of the toner T from the toner container 530 by contacting the developing roller 510 along the axial direction thereof.

<<< Example of operation of developing device >>>
In the yellow developing device 54 configured as described above, the toner supply roller 550 supplies the toner T stored in the toner container 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 the layer thickness is regulated and electric charge is applied when passing through the contact position. Is done. The toner T on the developing roller 510 to which the layer thickness is regulated and the electric charge is applied reaches the developing position facing the photosensitive member 20 by further rotation of the developing roller 510, and the photosensitive member is subjected to an alternating electric field at the developing position. The latent image formed on 20 is subjected to 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.

=== About the Surface Shape of the Developing Roller 510 and the Manufacturing Method Thereof ===
<<< Surface Shape of Developing Roller 510 >>>
First, the surface shape of the developing roller 510 of the yellow developing device 54 will be described with reference to FIGS. FIG. 8 is a schematic perspective view of the developing roller 510 and shows the recess 518. FIG. 9 is a schematic front view of the developing roller 510. FIG. 10 is a schematic diagram showing the surface of the developing roller 510, and is an enlarged view of a portion A shown in FIG. FIG. 11 is a schematic diagram showing the cross-sectional shapes of the convex portion 519 and the concave portion 518.

  8 to 10, the axial direction of the developing roller 510 is indicated by an arrow, and in FIG. 11, the longitudinal direction of the first recess 518a is indicated by an arrow. Further, in FIGS. 9 to 11, the scales of the convex portions 519 and the like are different from the actual ones for easy understanding of the drawings. 9 and 10, the direction of the arrow indicated by the symbol X indicates the longitudinal direction of the first recess 518a, and the direction of the arrow indicated by the symbol Y indicates the longitudinal direction of the second recess 518b. Yes. FIG. 11 shows a cross section along the longitudinal direction of the first recess 518a indicated by the symbol Y in FIG. In addition, the cross-sectional shape of the convex part 519 and the recessed part 518 when taking the cross section of the convex part 519 and the recessed part 518 along the longitudinal direction of the 2nd recessed part 518b shown by the symbol X of FIG. 9 is also shown in FIG. The cross-sectional shapes of the convex portion 519 and the concave portion 518 are the same.

  The cylindrical portion 510a of the developing roller 510 carries toner that forms particles on its surface. The cylindrical portion 510a is made of a single material such as an aluminum alloy, and as shown in FIG. 9, a concavo-convex portion 512 and a non-concave portion 514 are formed on the surface thereof.

  The concavo-convex portion 512 is a portion located at the center in the axial direction of the developing roller 510, and is provided with concavo-convex processing on the surface in order to properly carry the toner T (the convex portion 519 of the concavo-convex portion 512. And the concave portion 518 both function as a toner carrying portion for carrying the toner T). In the present embodiment, a so-called rolling process (the rolling process is described in detail in the section of the manufacturing method of the developing roller 510 described later) is used as the uneven process, and the uneven process part is formed by the rolling process. A concave portion 518 and a convex portion 519 are formed on the surface of 512. More specifically, a groove is formed on the surface of the concavo-convex portion 512 by rolling, and thus the concavo-convex portion 512 has a concave portion 518 and a convex portion 519.

As shown in FIG. 8, the recess 518 is a spiral groove having a predetermined inclination angle p with respect to the axial direction and the circumferential direction of the developing roller 510 and formed at an equal pitch in the axial direction. The recesses 518 are formed in two types with different inclination angles with respect to the axial direction and the circumferential direction of the developing roller 510 (a first recess 518a and a second recess 518b are formed).
That is, the first recess 518a is formed in a spiral shape so as to form an angle of 45 degrees counterclockwise with the axial direction of the developing roller 510, and the second recess 518b is clockwise with the axial direction of the developing roller 510. It is formed in a spiral shape so as to form an angle of 45 degrees. For this reason, the angle at which the first recess 518a and the second recess 518b intersect is 90 degrees. Further, the pitches of the first concave portion 518a and the second concave portion 518b in the axial direction of the developing roller 510 are equally formed, and in this embodiment, as shown in FIG. 10, it is about 112 μm.

As shown in FIG. 9, the convex portion 519 is provided so as to be surrounded by the two types of concave portions (that is, the first concave portion 518a and the second concave portion 518b). As shown in FIG. 11, the convex portion 519 includes a top surface 519a and a side surface 519b connected to the top surface 519a.
A flat portion is formed on the top surface 519a. The shape of the top surface 519a is substantially square as shown in FIG. The top surface 519a is arranged such that one of the two diagonal lines of the top surface 519a is along the axial direction of the developing roller 510 and the other diagonal line is along the circumferential direction of the developing roller 510. Is formed. The width W of the top surface 519a is about 30 μm in the present embodiment.
As shown in FIG. 11, the side surface 519b is a slope that is also connected to the flat bottom surface 518c of the recess 518 and is inclined with respect to the bottom surface 518c. The inclination angle of the side surface 519b from the bottom surface 518c of the recess 518 (the angle represented by the symbol β in FIG. 11) is 45 degrees or less, and in the present embodiment, the inclination angle is 45 degrees. .

  Further, the height of the convex portion 519 (depth of the concave portion 518), that is, the distance between the top surface 519a of the convex portion 519 and the bottom surface 518c of the concave portion 518 is less than twice the volume average particle diameter (7 μm) of the toner. is there. In this embodiment, since the depth of the recess 518 is about 7 μm, it is the same size as the volume average particle diameter of the toner. Further, the width of the recess 518 is about 30 μm, and the groove angle (the angle represented by the symbol α in FIG. 11) is about 90 degrees.

  As shown in FIG. 9, the non-recessed portion 514 is a portion where the aforementioned unevenness processing (rolling process) is not applied to the surface. The non-concavo-convex processed portion 514 is located between the uneven processed portion 512 and the shaft portion 510b in the axial direction of the developing roller 510, and the surface thereof is smooth (the ten-point average roughness of the surface). Rz is 1 μm or less).

  In the above description, the developing roller 510 of the yellow developing device 54 has been described. However, the printer 10 includes four developing rollers 510 that carry toners of four colors. The four developing rollers 510 have the same configuration, and the inclination angles p of the recesses 518 (first recesses 518a) are the same. That is, as shown in FIGS. 12A to 12D, the inclination angle p of the recess 518 (first recess 518a) of the developing roller 510 of each developing device is 45 degrees. 12A to 12D are schematic front views of the developing roller 510. FIG. 12A shows the developing roller 510 of the black developing device 51 (hereinafter also referred to as the black developing roller 510K), and FIG. 12B shows magenta. A developing roller 510 of the developing device 52 (hereinafter also referred to as a magenta developing roller 510M) is shown. FIG. 12C shows a developing roller 510 (hereinafter also referred to as a cyan developing roller 510C) of the cyan developing device 53, and FIG. A developing roller 510 (hereinafter also referred to as a yellow developing roller 510Y) of the developing device 54 is shown.

<<< About Manufacturing Method of Developing Roller 510 >>>
As described above, since the four developing rollers 510 have the same configuration, the manufacturing methods of the four developing rollers 510 are the same. Therefore, in the following, a method for manufacturing the developing roller 510 of the yellow developing device 54 will be described with reference to FIGS. 13A to 13E and FIG. FIGS. 13A to 13E are schematic diagrams showing the transition of the developing roller 510 in the manufacturing process of the developing roller 510. FIG. 14 is an explanatory diagram for explaining the rolling process of the developing roller 510. 13A to 13C show the cross section of the pipe material 600, and FIGS. 13D and 13E show the outer periphery of the pipe material 600, respectively.

  First, as shown in FIG. 13A, a pipe material 600 is prepared as a base material of the cylindrical portion 510a of the developing roller 510. The wall thickness of the pipe material 600 is 0.5 to 3 mm. Next, as shown in FIG. 13B, flange press-fit portions 602 are formed at both ends in the longitudinal direction of the pipe material 600. The flange press-fit portion 602 is made by cutting. Next, as shown in FIG. 13C, the flange 604 constituting the shaft portion 510 b of the developing roller 510 is press-fitted into the flange press-fit portion 602. In order to ensure the fixing of the flange 604 to the pipe material 600, the flange 604 may be bonded or welded to the pipe material 600 after the flange 604 is press-fitted.

  Next, as shown in FIG. 13D, centerless polishing is performed on the surface of the pipe member 600 into which the flange 604 is press-fitted. The centerless polishing is performed over the entire surface, and the 10-point average roughness Rz of the surface after the centerless polishing is 1.0 μm or less. Next, as shown in FIG. 13E, a concave portion 518 and a convex portion 519 are formed by rolling in a portion corresponding to the concave and convex portion 512 of the pipe member 600 into which the flange 604 is press-fitted. In the present embodiment, so-called through-feed rolling (also called step rolling or through rolling) using two round dies 650 and 652 is performed.

  That is, as shown in FIG. 14, two round dies 650 and 652 arranged so as to sandwich the pipe material 600 as a work are placed on the pipe material 600 with a predetermined pressure (the direction of the pressure in FIG. The two round dies 650 and 652 are rotated in the same direction (refer to FIG. 14) while being pressed with a symbol P). The surfaces of the round dies 650 and 652 are provided with projections 650a and 652a for forming the recesses 518, and the projections 650a and 652a deform the pipe material 600, thereby causing the pipe material 600 to protrude with the recesses 518 and Part 519 is formed. In the through-feed rolling, the round dies 650 and 652 rotate, so that the pipe material 600 rotates in the direction opposite to the rotation direction of the round dies 650 and 652 (see FIG. 14). Move in the direction indicated by H. In the portion corresponding to the concave and convex portion 512, the first concave portion 518a of the concave portion 518 is formed by the convex 650a of the round die 650, and the second concave portion 518b is formed by the convex 652a of the round die 652. It becomes.

=== Regarding the Positional Relationship between the Recess 518 and the Partition Area Row of the Screen
As described above, the developing roller 510 includes the concave portion 518 that has a predetermined inclination angle p with respect to the axial direction of the developing roller 510 and is a spiral groove portion at an equal pitch in the axial direction. Then, when the dot image latent image on the photoconductor 20 is visualized as a toner image by the toner carried on the developing roller 510 having the concave portion 518, density unevenness (due to the concave portion 518 in the toner image). For example, density unevenness due to the amount of toner carried on the recess 518 being greater than the amount of toner carried on a portion other than the recess 518 (that is, the projection 519) may occur periodically.

  Further, as described above, the photoconductor 20 carries a dot-like latent image on each mesh of the screen. A plurality of partitioned areas (partitioned area rows) in which the dot-like latent images are arranged in a row along a crossing direction intersecting a predetermined crossing angle q with respect to the axial direction of the central axis of the photoconductor 20. When carried on each, the plurality of dot-like latent images are also formed along the intersecting direction.

  Under such circumstances, depending on the relative position between the concave portion 518 and the partition region row of the screen, density unevenness due to the concave portion 518 may be easily noticeable in the visualized toner image. For example, when the photosensitive member 20 and the developing roller 510 rotate for developing a dot-like latent image, if the relative position of the partition area row with respect to the recess 518 coincides, the dots carried in each of the partition area rows The latent latent image may be visualized as a toner image by toner carried on the same portion of the recess 518 as shown in FIG. 16A. In such a case, there is a possibility that density unevenness due to the concave portion 518 is easily noticeable in the visualized toner image. FIG. 16A is a schematic diagram for explaining a comparative example, in which the apparent inclination angle of the concave portion 518 of the yellow developing roller 510Y and the intersection angle q of the partition region row C4 of the yellow screen have the same size. It is the figure which showed the case of.

  Therefore, in the printer 10 according to the present embodiment (hereinafter also referred to as the first embodiment), the positional relationship between the concave portion 518 and the partition region row is as follows in order to prevent the density unevenness from becoming conspicuous. ing. That is, when the developing roller 510 and the photosensitive member 20 rotate, the apparent inclination angle of the concave portion 518 (first concave portion 518a) of the developing roller 510 viewed from the photosensitive member 20 and the size of the intersection angle of the yellow screen , Are different. More specifically, the size of the tangent (tanp) of the inclination angle p of the recess 518 is defined as a ratio of the moving speed of the surface of the developing roller 510 to the moving speed of the surface of the photoconductor 20 (hereinafter, speed ratio). In other words, the value divided by the tangent (tanq) of the intersection angle q of the partition region row is different. This will be described in detail below.

  In the first embodiment, the “first developer” may be any of the four color toners, but in the following, the yellow toner corresponds to the “first developer”. . In such a case, of the four screens, the yellow screen partition region row corresponds to a “first partition region group” on which a dot image latent image visualized as a toner image by the first developer is carried. Therefore, description will be given by taking the concave portion 518 of the yellow developing roller 510Y and the partitioned area row C4 of the yellow screen as examples.

  As described above, the moving speed of the surface of the yellow developing roller 510Y is 1.4 times the moving speed of the surface of the photoconductor 20 (from this, the speed ratio is 1.4). The magnitude of the tangent of the apparent inclination angle pp of the recess 518 shown is obtained by dividing the magnitude of the tangent of the actual inclination angle p of the depression 518 (ie, 1) by the speed ratio (ie, 1.4). Value (ie 0.71). FIG. 15 is a conceptual diagram for explaining the apparent inclination angle pp of the recess 518. In FIG. 15, the concave portion 518 having an inclination angle p is indicated by a thick line, and the concave portion 518 having an apparent inclination angle pp is indicated by a dotted line.

  The tangent magnitude of the above-mentioned yellow screen intersection angle q is 2.75. Therefore, the value obtained by dividing the tangent of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y by the speed ratio (that is, 0.71) is the intersection angle q of the partition area row C4 of the yellow screen. It differs from the tangent size (ie 2.75).

  As described above, when the value is different from the tangent magnitude of the intersection angle q, as shown in FIG. 16B, the developing roller 510 and the photosensitive member 20 rotate to visualize the dot-like latent image as a toner image. In addition, the apparent inclination angle of the concave portion 518 of the yellow developing roller 510Y viewed from the photoreceptor 20 is different from the intersection angle of the yellow screen. For this reason, the dot-like latent image carried on each of the divided area rows of the yellow screen is visualized as a toner image by the toner carried on the same part of the concave part 518 (or the same part of the convex part 519). Can be prevented. Therefore, according to the printer 10 according to the first embodiment, it is possible to suppress the density unevenness from becoming conspicuous. FIG. 16B is a schematic diagram for explaining the effectiveness of the printer 10 according to the first embodiment, and the magnitude of the apparent inclination angle p of the concave portion 518 of the yellow developing roller 510Y is a section of the yellow screen. It is the figure which showed the state different from the magnitude | size of the crossing angle q of the area | region row | line C4.

<< Positional relationship between the recesses 518 of the four developing rollers 510 and the four divided region rows >>
In the above description, the concave portion 518 of the yellow developing roller 510Y and the partition area row C4 of the yellow screen have been described as examples. However, here, the four developing rollers 510 that respectively carry four colors of toner and the four colors Explains the positional relationship between four screens (yellow screen, magenta screen, cyan screen, and black screen) partitioned region rows on which dot-like latent images visualized as toner images are carried by the respective toners. To do.

  In the following, the positional relationship between the concave portions 518 of the yellow developing roller 510Y and the four screen partition area rows will be described, and then the concave portions 518 of the four developing rollers 510 including the yellow developing roller 510Y and the yellow screen will be described. The positional relationship between each of the four screens including each of the divided region rows will be described.

  First, the positional relationship between the concave portion 518 of the yellow developing roller 510Y and the divided area rows of the four screens will be described. In the first embodiment, the “second developer” whose color is different from the color of the first developer may be any toner other than the yellow toner of the four color toners. Corresponds to “second developer”. In such a case, the divided area row C2 of the magenta screen among the four screens corresponds to the “second divided area group” in which the dot image latent image visualized as the toner image by the second developer is carried.

  At this time, as described above, since the size of the intersection angle q of the partition region row C2 of the magenta screen is 20 degrees, the size of the tangent of the intersection angle q of the partition region row C2 is 0.36. Therefore, a value obtained by dividing the tangent magnitude of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y by the speed ratio (that is, 0.71) is the magnitude of the tangent of the intersection angle q of the magenta screen ( That is, it is different from 0.36).

  Similarly, since the size of the intersection angle q of the partition region row C3 of the cyan screen is 50 degrees, the size of the intersection angle q of the partition region row C3 is 1.19, and the intersection of the partition region row C1 of the black screen Since the size of the angle q is 90, the size of the tangent of the intersection angle q of the partition region row C1 is infinite. For this reason, the value obtained by dividing the tangent magnitude of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y by the speed ratio is equal to the tangent magnitude of the intersection angle q of the partition area row C3 of the cyan screen and the black screen. This is different from the size of the tangent of the intersection angle q of the partition region row C1.

  Thus, in the first embodiment, the value obtained by dividing the tangent of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y by the speed ratio (ie, 0.71) is the intersection of the four screens. It is different from the magnitude of the tangent of the angle q.

Next, the positional relationship between the recesses 518 of the four developing rollers 510 including the yellow developing roller 510Y and the partitioned area rows of the four screens including the yellow screen will be described.
As described above, since the magnitudes of the inclination angles p of the recesses 518 of the four developing rollers 510 are the same (that is, 45 degrees), the magnitude of the tangent of the inclination angles p of the four developing rollers 510 is The same. As described above, the tangent magnitude of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y is the ratio of the moving speed of the surface of each developing roller 510 to the moving speed of the surface of the photoconductor 20 ( That is, the value divided by 1.4) (that is, 0.71) is different from the tangent of the intersection angle q of the four screen partition region rows. Therefore, a value obtained by dividing the magnitude of the tangent of the inclination angle p of the recesses 518 of the four developing rollers 510 by the ratio of the moving speed of the surface of each developing roller 510 to the moving speed of the surface of the photoreceptor 20. Is different from any of the tangent magnitudes of the crossing angle q of the divided area rows of the four screens.

=== About the Second Embodiment ===
Next, 2nd embodiment is described using FIG. 17A-FIG. 17D. 17A to 17D are schematic front views of the developing roller 510. FIG. 17A shows the developing roller 510 of the black developing device 51, FIG. 17B shows the developing roller 510 of the magenta developing device 52, and FIG. FIG. 17D shows the developing roller 510 of the cyan developing device 53, and FIG. 17D shows the developing roller 510 of the yellow developing device 54.

  In the following, the positional relationship between the recess 518 of the developing roller 510 and the partition region row of the screen will be mainly described. For this reason, the configuration that omits the description of the configuration of the printer 10 is the same as the configuration of the printer 10 according to the first embodiment.

  In the second embodiment, the “first developer” and the “second developer” may be any of four color toners, but here, as in the first embodiment, the yellow toner is replaced with the “first developer”. It is assumed that magenta toner corresponds to “second developer”. In such a case, the yellow developing roller 510Y carries the first developer on the “first developer carrying roller”, and the magenta developing roller 510M carries the second developer on the “second developer carrying roller”. The partition area column C4 of the screen corresponds to the “first partition area group”, and the partition area column C2 of the magenta screen corresponds to the “second partition area group”. Therefore, first, the positional relationship between the concave portions 518 of the yellow developing roller 510Y and the magenta developing roller 510M and the partitioned area rows of the yellow screen and the magenta screen will be described.

  Since the yellow screen and the magenta screen according to the second embodiment are the same as the yellow screen and the magenta screen according to the first embodiment, respectively, the size of the intersection angle q of the partition area row C4 of the yellow screen is 70 degrees. The size of the intersection angle q of the partition region row C2 of the magenta screen is 20 degrees. On the other hand, unlike the first embodiment, the inclination angle p of the concave portion 518 (first concave portion 518a) of the yellow developing roller 510Y is 70 degrees as shown in FIG. 17D, and the concave portion 518 ( Unlike the first embodiment, the magnitude of the inclination angle p of the first recess 518a) is 50 degrees as shown in FIG. 17B. For this reason, the magnitude of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y is different from the magnitude of the inclination angle p of the concave portion 518 of the magenta developing roller 510M.

  At this time, since the magnitude of the tangent of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y is 2.75, the value obtained by dividing the magnitude of the tangent by the speed ratio (ie, 1.4) is 1.96. This value is the magnitude of the tangent of the intersection angle q of the partition area row C4 of the yellow screen (ie 2.75) and the magnitude of the tangent of the intersection angle q of the partition area row C2 of the magenta screen (ie 0 .36). Similarly, since the magnitude of the tangent of the inclination angle p of the concave portion 518 of the magenta developing roller 510M is 1.19, the value obtained by dividing the magnitude of the tangent by the speed ratio is 0.85. This value also corresponds to the size of the tangent of the crossing angle q of the mesh row of the yellow screen (ie, 2.75) and the size of the tangent of the crossing angle q of the mesh row of the magenta screen (ie, 0.36). Different.

  Next, regarding the relationship between the inclination angle p of the recesses 518 of the four developing rollers 510 including the yellow developing roller 510Y and the magenta developing roller 510M and the intersection angle q of the mesh rows of the four screens including the yellow screen and the magenta screen, explain.

  Since the cyan screen and the magenta screen according to the second embodiment are the same as the cyan screen and the magenta screen according to the first embodiment, respectively, the size of the intersection angle q of the partition area row C3 of the cyan screen is 50 degrees. The size of the intersection angle q of the black screen partition region row C1 is 90 degrees. Further, as described above, the size of the intersection angle q of the partition region row C4 of the yellow screen is 20 degrees, and the size of the intersection angle q of the partition region row C2 of the magenta screen is 70 degrees. The sizes of the crossing angles q of the divided area rows of the four screens are different from each other.

  Further, unlike the first embodiment, the inclination angle p of the concave portion 518 of the cyan developing roller 510C is 40 degrees as shown in FIG. 17C, and the inclination angle p of the concave portion 518 of the black developing roller 510K is also large. Unlike the first embodiment, the angle is 20 degrees as shown in FIG. 17A. Further, as described above, since the magnitude of the inclination angle p of the yellow developing roller 510Y is 70 degrees and the magnitude of the inclination angle p of the magenta developing roller 510M is 50 degrees, 4 in the second embodiment. The inclination angles p of the recesses 518 of the two developing rollers 510 are different from each other.

  In this case, since the tangent magnitude of the inclination angle p of the recess 518 of the cyan developing roller 510C is 0.84, the value obtained by dividing the tangent magnitude by the speed ratio (ie, 1.4) is Since the tangent magnitude of the inclination angle p of the concave portion 518 of the black developing roller 510K is 0.36, the value obtained by dividing the tangent magnitude by the speed ratio is 0.26. As described above, the value obtained by dividing the tangent of the inclination angle p of the concave portion 518 of the yellow developing roller 510Y by the speed ratio is 1.96, and the inclination angle p of the concave portion 518 of the magenta developing roller 510M. The value obtained by dividing the magnitude of tangent by the speed ratio is 0.85.

  The four values are the magnitude of the tangent of the intersection angle q of the partition area column C4 of the yellow screen (that is, 2.75), and the magnitude of the tangent of the intersection angle q of the partition area column C2 of the magenta screen (that is, 0.36), the tangent magnitude of the intersection angle q of the cyan screen partition area row C3 (ie 1.19), and the tangent magnitude of the intersection angle q of the black screen partition area row C1 (ie, , Infinite). Thus, the value obtained by dividing the magnitude of the inclination angle p of the recesses 518 of the four developing rollers 510 by the ratio of the moving speed of the surface of each developing roller 510 to the moving speed of the surface of the photoreceptor 20. Is different from any of the sizes of the intersection angles q of the four screen mesh rows.

  In the printer 10, as in the printer 10 according to the first embodiment, the value obtained by dividing the tangent of the inclination angle p of the yellow developing roller 510 </ b> Y by the speed ratio is a yellow screen partition region row C <b> 4. This is different from the tangent of the intersection angle q. In such a case, as in the case of the first embodiment, when the developing roller 510 and the photoconductor 20 rotate to visualize the dot-like latent image as a toner image, the yellow developing roller 510Y viewed from the photoconductor 20 The inclination angle of the recess 518 is different from the intersection angle of the yellow screen. For this reason, the dot-like latent image carried on each of the divided area rows of the yellow screen is visualized as a toner image by the toner carried on the same part of the concave part 518 (or the same part of the convex part 519). Can be prevented. Therefore, according to the printer 10 according to the second embodiment, it is possible to suppress the density unevenness from becoming conspicuous.

  In the above description, the size of the intersection angle q of the partition area rows of the four screens is different. However, as shown in FIGS. 18A to 18D, the size of the intersection angle q of the partition screen rows of the four screens is large. May be the same. 18A is a schematic diagram showing a black screen, FIG. 18B is a schematic diagram showing a magenta screen, FIG. 18C is a schematic diagram showing a cyan screen, and FIG. 18D is a yellow screen. It is the schematic diagram which showed.

  18A, the size of the intersection angle q of the partition region row of the yellow screen, the size of the intersection angle q of the partition region row of the magenta screen shown in FIG. 18B, and the intersection angle q of the partition region row of the cyan screen shown in FIG. And the size of the crossing angle q of the partition region row of the black screen shown in FIG. 18D is 50 degrees. At this time, the size of the tangent of the intersection angle q of the divided area rows of the four screens is 1.19. This value is the ratio of the tangent of the inclination angle p of the recesses 518 of the four developing rollers 510 to the moving speed of the surface of each developing roller 510 to the moving speed of the surface of the photoconductor 20. Different from each of the values divided by (ie 0.26, 0.6, 0.85, and 1.96).

  Further, in the above description, the inclination angles p of the four developing rollers 510 are different from each other, but the present invention is not limited to this. For example, two developing rollers 510 out of four developing rollers 510 may have the same inclination angle p.

=== Other Embodiments ===
The developing device and the like according to the present invention have been described above based on the above embodiment. However, the above-described embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. Absent. 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, the computer 702 includes the image processing unit 797. However, the present invention is not limited to this. For example, the printer 10 may include the image processing unit 797.

  In the above embodiment, an intermediate transfer type full color laser beam printer has been described as an example of the image forming apparatus. However, the present invention is not limited to the intermediate transfer type, but a full color laser beam printer, a monochrome laser beam printer, a copying machine, The present invention can be applied to various image forming apparatuses such as facsimiles.

  Also, the photosensitive member is not limited to a so-called photosensitive roller, which is configured by providing a photosensitive layer on the outer peripheral surface of a cylindrical conductive substrate, and is configured by providing a photosensitive layer on the surface of a belt-shaped conductive substrate. A so-called photosensitive belt may be used.

  In the above embodiment, the four color toner images are visualized on one photoconductor 20, but the present invention is not limited to this. For example, the printer 10 may include four photoconductors 20 on which toner images of different colors are visualized.

Further, in the above embodiment, the developing roller 510 has the cylindrical portion 510a having the surface, and the cylindrical portion 510a is made of a single material, but is not limited thereto. . For example, the cylindrical portion 510a may be made of a plurality of materials.
However, when the cylindrical portion 510a is made of a single material, the developing roller 510 having the convex portion 519 can be easily manufactured. Therefore, the above embodiment is more desirable.

  Further, in the above-described embodiment, the printer 10 is in contact with the developing roller 510 from one end to the other end in the axial direction of the developing roller 510 and has a layer thickness of the developer carried on the developing roller 510. It is assumed that a layer thickness regulating member (regulating blade 560) is provided. The regulation blade 560 regulates the layer thickness when the flat surface of the regulation blade 560 contacts the developing roller 510. However, it is not limited to the above. For example, the regulation blade 560 may not regulate the layer thickness.

Furthermore, in the above-described embodiment, the toner T is granular, and the depth of the recess 518 is not more than twice the volume average particle diameter of the toner T. However, the present invention is not limited to this. For example, the depth of the recess 518 may be larger than twice the volume average particle diameter of the toner T.
When the depth of the recess 518 is less than or equal to twice the volume average particle size of the toner, most of the toner positioned between the developing roller 510 and the rubber portion 562 in the recess 518 is mostly the developing roller 510 and the rubber portion. Since it contacts at least one of 562, the chargeability of the toner becomes appropriate. In this respect, the above embodiment is more desirable. When the depth of the concave portion 518 is equal to or smaller than the volume average particle diameter (one time) of the toner, most of the toner positioned between the developing roller 510 and the rubber portion 562 in the concave portion 518 is developed. This is even more desirable because it contacts both the roller 510 and the rubber portion 562.

1 is an explanatory diagram showing an external configuration of an image forming system 700. FIG. FIG. 2 is a block diagram illustrating a part of the configuration of the image forming system 700 illustrated in FIG. 1. FIG. 2 is a diagram illustrating main components constituting the printer. FIG. 4 is a block diagram showing a control unit of the printer 10 of FIG. 3. 5A is a schematic diagram showing a black screen, FIG. 5B is a schematic diagram showing a magenta screen, FIG. 5C is a schematic diagram showing a cyan screen, and FIG. 5D shows a yellow screen. It is a schematic diagram. It is a conceptual diagram of a developing device. It is sectional drawing which showed the main components of the image development apparatus. FIG. 5 is a schematic perspective view of the developing roller 510, and shows a recess 518. 2 is a schematic front view of a developing roller 510. FIG. FIG. 10 is a schematic view showing the surface of the developing roller 510, and is an enlarged view of a portion A shown in FIG. It is a schematic diagram showing the cross-sectional shape of a convex portion 519 and a concave portion 518. 12A shows the developing roller 510 of the black developing device 51, FIG. 12B shows the developing roller 510 of the magenta developing device 52, FIG. 12C shows the developing roller 510 of the cyan developing device 53, and FIG. A developing roller 510 of the developing device 54 is shown. FIGS. 13A to 13E are schematic diagrams showing the transition of the developing roller 510 in the manufacturing process of the developing roller 510. FIG. 6 is an explanatory diagram for explaining a rolling process of the developing roller 510. It is a conceptual diagram which calculates the tangent of the inclination angle p in consideration of speed ratio. FIG. 16A is a schematic diagram for explaining a comparative example, and FIG. 16B is a schematic diagram for explaining an effect of the printer 10 according to the first embodiment. 17A shows the developing roller 510 of the black developing device 51, FIG. 17B shows the developing roller 510 of the magenta developing device 52, FIG. 17C shows the developing roller 510 of the cyan developing device 53, and FIG. A developing roller 510 of the developing device 54 is shown. 18A is a schematic diagram showing a black screen, FIG. 18B is a schematic diagram showing a magenta screen, FIG. 18C is a schematic diagram showing a cyan screen, and FIG. 18D shows a yellow screen. It is a schematic diagram.

Explanation of symbols

10 printer, 20 photoconductor, 30 charging unit, 40 exposure unit,
50 YMCK developing unit, 50a central axis, 51 black developing device,
52 magenta developing device, 53 cyan developing device, 54 yellow developing device,
55a, 55b, 55c, 55d holding part, 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, 112 interface, 113 image memory,
510 developing roller, 510a cylindrical portion, 510b shaft portion,
510K black developing roller, 510M magenta developing roller,
510C cyan developing roller, 510Y yellow developing roller,
512 concavo-convex processed part, 514 non-concave processed part, 518 concave part,
518a first recess, 518b second recess, 519 projection,
519a top surface, 519b side surface, 519c joint,
520 upper seal, 520a short side end, 520b contact surface,
520c opposite surface, 524 upper seal biasing member,
530 toner container, 530a first toner container,
530b second toner storage portion, 540 housing, 542 upper housing portion,
544 Lower housing portion, 545 partition wall, 550 toner supply roller,
560 regulating blade, 560a tip, 562 rubber part, 562a contact part,
564 rubber support, 564a thin plate, 564b thin plate support,
564c Longitudinal ends, 564d Short end,
564e, the other end in the short direction, 572 opening,
600 pipe material, 602 flange press-fit part, 604 flange,
650 round die, 650a convex, 652 round die, 652a convex,
700 image forming system, 702 computer, 704 display device,
708 input device, 708A keyboard, 708B mouse,
710 reading device, 710A FD device, 710B CD-ROM drive device,
795 application program, 796 printer driver,
797 Image processing unit, 801 Display interface unit,
803 input interface unit, 805 user interface processing unit,
AD image data, COM control signal, PD image data,
T Toner

Claims (6)

(A) an image carrier that is rotatable about a central axis,
A plurality of partitioned regions arranged in a row along a direction intersecting the axial direction of the central axis at a predetermined intersection angle on the surface of the image carrier;
An image carrier that carries a dot-like latent image on each of
(B1) Opposite to the image carrier so that the axial direction thereof is parallel to the axial direction of the image carrier, and the dot-like latent material carried on the image carrier by the developer carried on the surface thereof A rotatable developer carrying roller for visualizing the image as a developer image,
(B2) a developer carrying roller provided on the surface with a spiral groove having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at an equal pitch in the axial direction;
A (c) possess,
(D) The developer carrying roller includes four developer carrying rollers carrying each of the four color developers,
The inclination angles of the grooves of the four developer carrying rollers are the same,
(D) the plurality of partitioned areas form a partitioned area group;
As the partitioned area groups, each of the four color developers includes four partitioned area groups on which dot latent images visualized as developer images are respectively carried,
The sizes of the crossing angles of the four divided region groups are different from each other,
(E) The ratio of the tangent of the inclination angle of the groove portions of the four developer carrying rollers to the moving speed of the surface of each developer carrying roller to the moving speed of the surface of the image carrier, divided by the image forming apparatus according to claim with any different Rukoto the magnitude of the angle of intersection tangent of the four divided areas group. The image forming apparatus according to claim 1,
The developer carrying roller has a cylindrical portion provided with the surface,
The cylindrical portion is made of a single material. The image forming apparatus according to claim 1 , wherein:
A layer thickness regulating member for regulating the layer thickness of the developer carried on the developer carrying roller in contact with the developer carrying roller from one end to the other end in the axial direction of the developer carrying roller With
The image forming apparatus according to claim 1, wherein the layer thickness regulating member regulates the layer thickness when a plane of the layer thickness regulating member abuts against the developer carrying roller. The image forming apparatus according to any one of claims 1 to 3 ,
The developer is granular,
The depth of the groove is less than twice the volume average particle diameter of the developer. The image forming apparatus according to any one of claims 1 to 4 ,
The developer carrying roller has the groove and the convex on the surface thereof,
The image forming apparatus according to claim 1, wherein the groove and the convex are both carrying parts for carrying the developer. (A) a computer, and
(B) An image forming apparatus connectable to the computer,
(A) an image carrier that is rotatable about a central axis,
A plurality of partitioned regions arranged in a row along a direction intersecting the axial direction of the central axis at a predetermined intersection angle on the surface of the image carrier;
An image carrier that carries a dot-like latent image on each of
(B1) Opposite to the image carrier so that the axial direction thereof is parallel to the axial direction of the image carrier, and the dot-like latent material carried on the image carrier by the developer carried on the surface thereof A rotatable developer carrying roller for visualizing the image as a developer image,
(B2) a developer carrying roller provided on the surface with a spiral groove having a predetermined inclination angle with respect to the axial direction of the developer carrying roller and formed at an equal pitch in the axial direction;
A (c) possess,
(D) The developer carrying roller includes four developer carrying rollers carrying each of the four color developers,
The inclination angles of the grooves of the four developer carrying rollers are the same,
(D) the plurality of partitioned areas form a partitioned area group;
As the partitioned area groups, each of the four color developers includes four partitioned area groups on which dot latent images visualized as developer images are respectively carried,
The sizes of the crossing angles of the four divided region groups are different from each other,
(E) The ratio of the tangent of the inclination angle of the groove portions of the four developer carrying rollers to the moving speed of the surface of each developer carrying roller to the moving speed of the surface of the image carrier, divided by the with any different that the image forming apparatus of the magnitude of the angle of intersection tangent of the four compartments region groups,
An image forming system comprising (C).

Images