JP2009031522A - Image forming apparatus, image forming system and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, an image forming system and an image forming method, suitably preventing deterioration of image quality of an image. <P>SOLUTION: This image forming apparatus includes: an image support for supporting a latent image; a developer carrier having recessed parts regularly arranged on the surface thereof; a contact member, which is made of elastic rubber body, abutted on the surface of the developer carrier, and vibrated with the rotation of the developer carrier; and a controller. In the controller, after the rotation of the developer carrier is started, the rotating speed of the developer carrier is increased to a first rotating speed V1 in which a movement speed of the surface at the time of rotation of the developer carrier is larger than a product of a pitch of the recessed parts in a peripheral direction of the developer carrier by the number of vibrations of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest, and after the rotating speed of the developer carrier reaches the first rotating speed, the rotating speed of the developer carrier is decreased to a second rotating speed V2 in which a movement speed is smaller than the above product, and the developer carrier rotating at the second rotating speed is caused to develop the latent image. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  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 latent image and a developing device for developing the latent image carried on the image carrier by a developer. Then, when an image signal or the like is transmitted from an external device such as a computer, the image forming apparatus develops the latent image carried on the image carrier with the developer in the developing device to form a developer image, The developer image is transferred to a medium, and finally an image is formed on the medium.

  The developing device described above includes a rotatable developer carrying member for carrying the developer, and the developer carrying member develops the latent image with the developer carried on the developer carrying member. Do. Some of these developer carriers are provided with concave portions regularly arranged on the surface thereof.

Further, the developing device is provided with an abutting member that abuts on the surface of the developer carrying member and is made of a rubber elastic body. Examples of the contact member include a layer thickness regulating member for regulating the layer thickness of the developer carried on the developer carrying member.
JP 2006-259384 A

  By the way, as described above, the contact member is in contact with the surface of the developer carrier, and the surface of the developer carrier is provided with regularly arranged recesses. Therefore, when the developer carrying body rotates, the contact member vibrates as the developer carrying body slides with respect to the contact member.

  The frequency of the contact member (the value obtained by dividing the moving speed of the surface when the developer carrying member rotates by the pitch in the circumferential direction of the developer carrying member of the concave portion corresponds to the frequency. Is too large, the contact member made of a rubber elastic body is known to show glassy properties instead of rubbery properties, and therefore, when development is performed, It is necessary to rotate the developer carrying member at such a rotational speed that the frequency does not become excessively high (that is, the contact member does not exhibit glassy properties).

  However, when the development is performed in a state in which the contact member exhibits a rubber-like property, filming occurs in the contact member due to the tackiness of the contact member based on the rubber-like property. When the filming becomes noticeable, the image quality of the image that is developed and finally formed on the medium is deteriorated.

  The present invention has been made in view of such a problem, and an object of the present invention is to appropriately prevent deterioration in image quality of an image.

  The main present invention is (A) an image carrier for carrying a latent image, and (B) a rotatable developer carrier for carrying a developer, which has regularly arranged concave portions on the surface. A developer carrying body for developing the latent image with the developer carried on the developer carrying body, and (C) abutting against the surface of the developer carrying body, the developer carrying body A contact member made of a rubber elastic body that vibrates with the rotation of the developer carrying member, and (D) the developer carrying member is rotated at a rotational speed of the developer carrying member after the developer carrying member starts to rotate. Corresponding when the moving speed of the surface at the time is the loss tangent obtained by dividing the pitch of the concave portion in the circumferential direction of the developer carrier and the loss elastic modulus of the contact member by the storage elastic modulus. The rotation of the developer carrier is increased to a first rotation speed that is greater than the product of the frequency of the contact member and After the rotation speed reaches the first rotation speed, the rotation speed of the developer carrier is lowered to a second rotation speed at which the moving speed is smaller than the product, and the developer carrying member rotates at the second rotation speed. An image forming apparatus comprising: a controller that causes the developer carrying member to develop the latent image; and (E).

  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 for carrying a latent image, and (B) a rotatable developer carrier for carrying a developer, which is provided with regularly arranged concave portions on the surface thereof. A developer carrying member that develops the latent image with the developer carried on the developer carrying member, and (C) abutting against the surface of the developer carrying member, and vibrating as the developer carrying member rotates. A contact member made of a rubber elastic body, and (D) the rotation speed of the developer carrier after the rotation of the developer carrier is started. The frequency of movement of the corresponding contact member when the loss tangent of the concave portion, the pitch in the circumferential direction of the developer carrier, and the loss elastic modulus of the contact member divided by the storage elastic modulus is maximized. And the rotation speed of the developer carrier is increased to the first rotation speed, which is larger than the product of After that, the rotation speed of the developer carrier is lowered to a second rotation speed at which the moving speed is smaller than the product, and the developer carrier that rotates at the second rotation speed is reduced. An image forming apparatus comprising: a controller for developing the latent image; and (E).
According to such an image forming apparatus, deterioration of the image quality of the image is appropriately prevented.

  A developing bias applying unit configured to apply a developing bias to the developer carrying member for developing the latent image; and the controller has a rotation speed of the developer carrying member set to the first rotation speed. Thereafter, the rotation speed of the developer carrier is decreased from the first rotation speed to the second rotation speed via a third rotation speed at which the moving speed is equal to the product, and Application of the development bias by the development bias application unit may be started after the rotation speed of the developer carrying member reaches the third rotation speed.

In such a case, the filming is properly collected.
In addition, the controller may be configured such that the rotation speed of the developer carrier among the surfaces of the developer carrier is the third rotation speed after the rotation speed of the developer carrier is the third rotation speed. The developing bias after the time at which the portion of the contact member that contacts the contact member moves to a position facing the image carrier with the further rotation of the developer carrier. Application of the developing bias by the application unit may be started.
In such a case, the filming is recovered more appropriately.

Next, (A) an image carrier for carrying a latent image, and (B) a rotatable developer carrier for carrying a developer provided with regularly arranged concave portions on the surface. A developer carrying member that develops the latent image with the developer carried on the developer carrying member; and (C) the developer carrying member that is in contact with the surface of the developer carrying member and rotating the developer carrying member. A contact member made of a rubber elastic body that vibrates along with, and (D) the movement speed of the surface when the developer carrier rotates, and the pitch of the recesses in the circumferential direction of the developer carrier The developer carrier that rotates at a fifth rotational speed that is smaller than the product of the frequency of the contact member when the loss tangent of the contact member divided by the storage elastic modulus becomes the maximum, and the loss frequency. After the latent image is developed on the body and the development of the latent image is finished, the rotational speed of the developer carrier A controller that increases the moving speed to a fourth rotational speed that is greater than the product, and stops the rotation of the developer carrier after the rotational speed of the developer carrier reaches the fourth rotational speed; And (E).
According to such an image forming apparatus, deterioration of the image quality of the image is appropriately prevented.

  A developing bias applying unit configured to apply a developing bias to the developer carrying member for developing the latent image; and the controller finishes developing the latent image and then removes the developer carrying member from the developer carrying member. The rotational speed is increased from the fifth rotational speed to the fourth rotational speed via a third rotational speed at which the moving speed is equal to the product, and the rotational speed of the developer carrier is A portion of the surface of the developer carrying member that comes into contact with the contact member when the rotation speed of the developer carrying member reaches the third rotation speed after reaching the third rotation speed. The application of the developing bias by the developing bias applying unit may be terminated before the time when the developer carrying member further moves to a position facing the image carrier with the further rotation has elapsed. Good.

In such a case, the filming is properly collected.
Further, the development bias application by the development bias application unit may be terminated before the rotation speed of the developer carrying member reaches the third rotation speed.

In such a case, the filming is more reliably collected.
Further, the controller has a stripping member for contacting the surface of the developer carrier and stripping the developer from the developer carrier, and the controller has a rotation speed of the developer carrier. When the rotation of the developer carrier is stopped after the fourth rotation speed is reached, the rotation speed of the developer carrier becomes the third rotation speed. The position where the contact member abuts when the rotation speed of the developer carrying body reaches the third rotation speed is a position where the stripping member comes into contact with further rotation of the developer carrying body. The rotation may be stopped after the time when the time to move to elapses.

In such a case, the filming is appropriately peeled off by the peeling member before the developer carrying member stops.
Also, a computer and an image forming apparatus connectable to the computer, comprising an image carrier for carrying a latent image and regularly arranged recesses on the surface for carrying a developer A rotatable developer carrier, which is in contact with the developer carrier for developing the latent image with the developer carried on the developer carrier, and the surface of the developer carrier; A contact member made of a rubber elastic body that vibrates with the rotation of the developer carrier, and the rotation of the developer carrier after the rotation of the developer carrier is started. When the rotational speed of the surface during rotation is maximized, the loss tangent obtained by dividing the pitch of the concave portion in the circumferential direction of the developer carrier and the loss elastic modulus of the contact member by the storage elastic modulus The first rotational speed that is greater than the product of After the rotation speed of the developer carrier becomes the first rotation speed, the rotation speed of the developer carrier is lowered to a second rotation speed at which the moving speed is smaller than the product. And an image forming apparatus having a controller that causes the developer carrying member rotating at the second rotation speed to develop the latent image.
According to such an image forming system, deterioration of the image quality of the image is appropriately prevented.

Also, a computer and an image forming apparatus connectable to the computer, comprising an image carrier for carrying a latent image and regularly arranged recesses on the surface for carrying a developer A rotatable developer carrier, which is in contact with the developer carrier for developing the latent image with the developer carried on the developer carrier, and the surface of the developer carrier; The contact member made of a rubber elastic body that vibrates with the rotation of the developer carrying member and the moving speed of the surface when the developer carrying member rotates are determined by the circumference of the developer carrying member of the recess. Rotating at a fifth rotational speed that is smaller than the product of the direction pitch and the frequency of the contact member when the loss tangent of the contact member divided by the storage elastic modulus is the maximum. The developer carrying member is allowed to develop the latent image, and the development of the latent image is terminated. After that, the rotational speed of the developer carrier is increased to a fourth rotational speed at which the moving speed is greater than the product, and the rotational speed of the developer carrier becomes the fourth rotational speed. And an image forming apparatus having a controller for stopping the rotation of the developer carrying member.
According to such an image forming system, deterioration of the image quality of the image is appropriately prevented.

Further, the developer support is a rotatable developer support having a regularly arranged concave portion on the surface for supporting the developer, and is supported on the image support with the developer supported on the developer support. The rotation of the developer carrying member that develops the latent image is started, and the rotational speed of the developer carrying member is determined by the speed of movement of the surface when the developer carrying member is rotated. Of the circumferential direction of the developer carrier, and loss elasticity of a contact member made of a rubber elastic body that is in contact with the surface of the developer carrier and vibrates with the rotation of the developer carrier. A first rotational speed that is greater than the product of the vibration frequency of the corresponding member when the loss tangent divided by the storage elastic modulus is maximized, and the rotational speed of the developer carrier is After reaching the first rotation speed, the rotation speed of the developer carrier is changed to the moving speed. And a step of causing the developer carrying member that rotates at the second rotation speed to develop the latent image. An image forming method can also be realized.
According to such an image forming method, deterioration of the image quality of the image is appropriately prevented.

Further, the developer support is a rotatable developer support having a regularly arranged concave portion on the surface for supporting the developer, and is supported on the image support with the developer supported on the developer support. The speed of movement of the surface when the developer carrying member that develops the latent image rotates depends on the pitch of the concave portion in the circumferential direction of the developer carrying member and the surface of the developer carrying member. The frequency of the contact member when the loss tangent obtained by dividing the loss elastic modulus by the storage elastic modulus of the contact member made of a rubber elastic body that is in contact and vibrates with the rotation of the developer carrying member becomes maximum. And a step of causing the developer carrying member rotating at a fifth rotation speed smaller than the product of the development of the latent image to develop the latent image, and after the development of the latent image is completed, the rotation of the developer carrying member. Increase the speed to a fourth rotation speed at which the moving speed is greater than the product. And a step of stopping the rotation of the developer carrying member after the rotation speed of the developer carrying member reaches the fourth rotation speed. .
According to such an image forming method, deterioration of the image quality of the image is appropriately prevented.

=== Example of Overall Configuration of Image Forming Apparatus ===
Next, an outline of a laser beam printer (hereinafter also referred to as a printer) 10 as an example of the image forming apparatus will be described with reference to FIG. FIG. 1 is a diagram illustrating main components constituting the printer 10. In FIG. 1, the vertical direction is indicated by arrows. For example, the paper feed tray 92 is disposed at the lower part of the printer 10, and the fixing unit 90 is disposed at the upper part of the printer 10.

<<< Configuration Example of Printer 10 >>>
As shown in FIG. 1, the printer 10 according to the present embodiment includes a charging unit 30, an exposure unit 40, and a YMCK along the rotation direction of a photoconductor 20 as an example of an image carrier for carrying a latent image. A developing unit 50, a primary transfer unit 60, an intermediate transfer member 70, and a cleaning unit 75; a secondary transfer unit 80; a fixing unit 90; It has a controller 100 that controls these units 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 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 photoconductor 20 into toner as an example of a developer contained in the developing device, that is, black (K) toner contained in the black developing device 51, magenta development. An apparatus for developing using magenta (M) toner stored in the device 52, cyan (C) toner stored in the cyan developing device 53, and yellow (Y) toner stored in the yellow developing device 54. is there.

  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 accommodated in each developing device 51, 52, 53, 54. The latent images are developed sequentially. Each of the four developing devices 51, 52, 53, and 54 described above can be attached to and detached from the printer main body 10a (specifically, 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. This intermediate transfer body 70 is an endless belt in which a tin 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 remaining on the photoreceptor 20 is scraped off and removed by the cleaning blade 76.

  As shown in FIG. 2, the controller 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 unit according to a command based on the image signal and the control signal. A 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 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 (negative polarity in the present embodiment) 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 toner adhering to the surface of the photoreceptor 20 is scraped off by the cleaning blade 76 supported by the cleaning unit 75, and is charged for forming the next latent image. Prepare. The toner that has been scraped off is collected by a residual toner collecting unit provided in the cleaning unit 75.

=== Overview of Controller ===
Next, the configuration of the controller 100 will be described with reference to FIG. A main controller 101 of the controller 100 is electrically connected to a host computer via an interface 112 and includes an image memory 113 for storing an image signal input from the host computer. 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 them.

=== About Development Device ===
Next, a configuration example and an operation example of the developing device will be described with reference to FIGS. FIG. 3 is a conceptual diagram of the developing device. FIG. 4 is a cross-sectional view showing main components of the developing device. FIG. 5 is a schematic perspective view of the developing roller 510. FIG. 6 is a schematic front view of the developing roller 510. FIG. 7 is a schematic diagram showing a cross-sectional shape of the groove 512. FIG. 8 is an enlarged schematic view of FIG. 6 and shows the groove portion 512 and the top surface 515. Note that the cross-sectional view shown in FIG. 4 represents a cross-section obtained by cutting the developing device along a plane perpendicular to the longitudinal direction shown in FIG. 4, the vertical direction is indicated by arrows as in FIG. 1. For example, the central axis of the developing roller 510 is below the central axis of the photoconductor 20. Further, in FIG. 4, the yellow developing device 54 is shown in a state where the yellow developing device 54 is located at a developing position facing the photoconductor 20. 5 to 8, the scales of the groove portions 512 and the like are different from the actual ones for easy understanding of the drawings.

  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 carrier, an upper seal 520, a toner container 530, a housing 540, a toner supply roller 550 as an example of a peeling member, and a regulation as an example of a contact member. A blade 560, a holder 526, and the like are included.

  The developing roller 510 carries the toner T and conveys the toner T by rotating it to the developing position facing the photoconductor 20, and the latent image carried on the photoconductor 20 with the toner T (toner T carried on the developing roller 510). Develop the image. The developing roller 510 is a member made of an aluminum alloy, an iron alloy, or the like.

  As shown in FIGS. 5 and 6, the developing roller 510 has a groove portion 512 as an example of a concave portion on the surface of the central portion 510 a in order to appropriately carry the toner T. In the present embodiment, as the groove portion 512, two types of spiral groove portions 512 having different winding directions, that is, a first groove portion 512a and a second groove portion 512b are provided. As shown in FIG. 6, the inclination angles of the first groove portion 512a and the second groove portion 512b with respect to the circumferential direction of the developing roller 510 are different from each other, and the longitudinal direction of the first groove portion 512a and the axial direction of the developing roller 510 are different. And the magnitude of the acute angle formed by the longitudinal direction of the second groove portion 512b and the axial direction are both about 45 degrees. As shown in FIG. 7, the width in the X direction of the first groove portion 512a and the width in the Y direction of the second groove portion 512b are about 42 μm, the depth of the groove portion 512 is about 7 μm, and the groove angle (in FIG. Is an angle of about 90 degrees.

  Further, the groove 512 includes a bottom surface 514 and a side surface 513. In this embodiment, the inclination angle of the side surface 513 is about 45 degrees (see FIG. 7).

  The two types of spiral grooves 512 configured as described above are regularly arranged on the surface of the central portion 510a of the developing roller 510 and intersect each other, as shown in FIGS. And has a lattice shape. Therefore, a large number of rhombus (square) top surfaces 515 surrounded on all sides by the groove portion 512 are formed on the mesh at the central portion 510a.

  As described above, in the present embodiment, the size of the acute angle formed by the longitudinal direction of the first groove portion 512a and the axial direction, and the size of the acute angle formed by the longitudinal direction of the second groove portion 512b and the axial direction, Since both are approximately 45 degrees, the top surface 515 has a square planar shape, and one (the other) of the two diagonal lines of the top surface 515 is the circumferential direction of the developing roller 510. (Axial direction).

  As shown in FIG. 7, the length of one side of the square top surface 515 is about 38 μm, and the circumferential pitch (width L1 shown in FIG. 8) of the grooves 512 is about 113 μm. .

  Further, the developing roller 510 is rotatable around the central axis, and as shown in FIG. 4, the developing roller 510 is rotated in a direction (counterclockwise in FIG. 4) opposite to the rotation direction of the photoconductor 20 (clockwise in FIG. 4). Rotate. In the present embodiment, the moving speed of the surface of the developing roller 510 when the developing roller 510 rotates when the latent image is developed (that is, the line of the developing roller 510 on the surface of the developing roller 510). Speed) is about 320 mm / s. The moving speed of the surface of the photoconductor 20 when the photoconductor 20 rotates when the latent image is developed (that is, the linear velocity of the photoconductor 20 on the surface of the photoconductor 20) is about 200 mm. / S, and the peripheral speed ratio of the developing roller 510 to the photosensitive member 20 is about 1.6.

  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. The printer 10 also has a developing bias applying unit for applying a developing bias (a developing voltage in which an AC voltage is superimposed on a DC voltage) to the developing roller 510 for developing a latent image. 121 (FIG. 2) is provided. Then, when a developing bias is applied to the developing roller 510, an alternating electric field is formed in the gap. Due to this alternating electric field, the toner T on the developing roller 510 moves to the photoconductor 20, and as a result, the latent image on the photoconductor 20 is developed.

  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 dividing the toner T projected inwardly (in the vertical direction in FIG. 4) from the inner wall. It is divided into the accommodating portion 530b. As shown in FIG. 4, 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 (in contact with the surface of the developing roller 510). 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. 4) opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 4).

  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 sheet metal 522. On the opposite side of the upper seal 520 from the developing roller 510 side, an upper seal urging member 524 made of an elastic body such as malt plain 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 contact position at which the upper seal 520 contacts the developing roller 510 is above the central axis of the developing roller 510.

  The regulating blade 560 is in contact with the surface of the developing roller 510 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. Charge is applied to the toner T carried on 510. As shown in FIG. 4, the regulation blade 560 includes a rubber part 562 as an example of a contact member and a rubber support part 564.

  The rubber portion 562 is a layer thickness regulating member that abuts on the surface of the developing roller 510 and regulates the layer thickness of the toner T carried on the developing roller 510. The rubber portion 562 has a longitudinal direction along the axial direction of the developing roller 510 (FIG. 6), and one end in the short direction (the tip 560a of the regulating blade 560) is upstream of the developing roller 510 in the rotation direction. (See FIG. 4). That is, the rubber part 562 is in contact with a so-called counter. Further, the one end of the rubber part 562 (the tip 560a of the regulating blade 560) is not in contact with the developing roller 510, and the contact part 562a of the rubber part 562 that contacts the surface of the developing roller 510 is the short side. In a direction away from the tip 560a. That is, the rubber portion 562 is not in contact with the developing roller 510 at the edge, but is in contact with the antinode, and the flat surface of the rubber portion 562 is in contact with the developing roller 510, thereby regulating the layer thickness. To do. Note that the contact position where the rubber portion 562 contacts the developing roller 510 is below the central axis of the developing roller 510 and below the central axis of the toner supply roller 550. The rubber portion 562 also has a function of preventing the leakage of the toner T from the toner container 530 by contacting the developing roller 510 along the axial direction thereof.

  By the way, the rubber part 562 mentioned above consists of a rubber elastic body. Here, the rubber elastic body is defined as an elastic body having rubber elasticity. This rubber elastic body is classified into a rubber and a thermoplastic elastomer, and the rubber is an elastic body that is solidified from a fluidized state by heating (that is, an elastic body that exhibits thermosetting property). It is an elastic body that fluidizes from a solidified state (ie, an elastic body that exhibits thermoplasticity). In addition, examples of the rubber used as the rubber portion 562 include urethane rubber. And rubber part 562 concerning this embodiment consists of thermoplastic elastomer from a viewpoint etc. which are easy to process by the thermoplasticity.

  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 housing 540 in a state where the opposite end is supported. Further, a blade back member 570 made of malt plane or the like is provided on the side opposite to the developing roller 510 side of the thin plate supporting portion 564b.

<<< 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 when the toner T passes through the contact position, the layer thickness is regulated and a negative charge is applied. Is imparted (negatively charged). The toner T on the developing roller 510 to which the layer thickness is regulated and to which a negative charge is applied is conveyed to a facing position (developing position) facing the photoconductor 20 by further rotation of the developing roller 510, and is moved to the facing position. Then, the latent image formed on the photoconductor 20 is developed. The toner T on the developing roller 510 that has passed the developing position by the 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.

=== Regarding Start-up Control and Fall-down Control of the Developing Roller 510 ===
As described above, the developing roller 510 rotates to convey the toner to the developing position, and develop the latent image carried on the photoconductor 20 with the toner (toner carried on the developing roller 510). When the developing roller 510 performs the development, the developing roller 510 rotates at a constant rotational speed (hereinafter, the rotational speed is also referred to as a developing rotational speed for convenience) (in the present embodiment, the developing roller 510). The surface moves at a rotation speed of about 320 mm / s.)
Therefore, the controller 100 needs to control the rotation of the developing roller 510 that is stopped at the start of development to increase the rotational speed of the developing roller 510 to the rotational speed during development. Further, at the end of development, the controller 100 needs to control the rotation of the developing roller 510 rotating at the developing rotation speed to lower the rotation speed of the developing roller 510 to 0 (that is, the It is necessary to stop the rotation of the developing roller 510).

  Here, how the controller 100 controls the rotation of the developing roller 510 until the developing roller 510 rotates from the stopped state to the rotation speed at the time of development (hereinafter, this control is referred to as the developing roller 510 for convenience). Will be described). Further, how the controller 100 controls the rotation of the developing roller 510 from the state where the developing roller 510 rotates at the developing rotation speed to the stop state (hereinafter, this control is referred to as the developing roller 510 for convenience. Will be described.

<<< Basic concept of control >>>
As described in the section of the problem to be solved by the invention, the contact member (in this embodiment, the rubber portion 562 which is a layer thickness regulating member) is in contact with the surface of the developing roller 510. In addition, regularly arranged grooves 512 are provided on the surface of the developing roller 510. Therefore, when the developing roller 510 rotates, the developing roller 510 slides with respect to the rubber portion 562, so that the rubber portion 562 vibrates.

  The frequency of the rubber portion 562 (the value obtained by dividing the moving speed of the surface when the developing roller 510 rotates by the pitch of the groove portion 512 in the circumferential direction of the developing roller 510 corresponds to the frequency. When the development is performed, it is known that the rubber portion 562 made of a rubber elastic body exhibits a glass-like property instead of a rubber-like property. Rotational speed at which the frequency does not become excessively high (that is, the rubber portion 562 does not exhibit glassy properties) so that the function of the rubber portion 562 made of a rubber elastic body is appropriately exhibited. Therefore, the developing roller 510 needs to be rotated.

  This matter will be described in more detail. By the way, there are a storage elastic modulus and a loss elastic modulus which show the dynamic viscoelasticity of a substance such as the rubber part 562 made of a rubber elastic body. The storage elastic modulus represents the elastic behavior of the substance, and the loss elastic modulus represents the viscous behavior of the substance. Both values fluctuate according to changes in the frequency of the substance when the substance vibrates. In addition, since both values fluctuate according to the change in the frequency, so-called loss tangent tan δ obtained by dividing the loss elastic modulus G ″ by the storage elastic modulus G ′ also fluctuates according to the change in the frequency. It is known that the property of the substance changes with the frequency of the substance when the loss tangent tan δ is maximized as the boundary (hereinafter, the frequency is also referred to as the boundary frequency f). When the vibration frequency of the material is smaller than the boundary frequency f, the material exhibits rubber-like properties, and when the material is larger than the boundary frequency f, the material exhibits glassy properties. It is known to show.

  FIG. 9 shows the relationship between the frequency (hereinafter also referred to as frequency for convenience), the storage elastic modulus, the loss elastic modulus, and the loss tangent of the substance (that is, the rubber part 562) according to the present embodiment. It is the shown graph. As shown in FIG. 9, the storage elastic modulus G ′, the loss elastic modulus G ″, and the loss tangent tan δ also fluctuate according to the change in the frequency of the rubber portion 562 in the rubber portion 562 according to the present embodiment. For the rubber portion 562, the boundary frequency f is about 6700 Hz, and therefore when the rubber portion 562 has a vibration frequency smaller than about 6700 Hz when the rubber portion 562 vibrates, When the rubber part 562 exhibits a rubbery property and is higher than about 6700 Hz, the rubber part 562 exhibits a glassy property.

  In addition, the graph shown in FIG. 9 is calculated | required by the following measurements. An ARES manufactured by TA Instruments is used as a measuring instrument for this measurement, and a torsion type tool is used as a jig for the measurement. Further, the frequency dependent measurement mode is selected as the measurement mode, and the applied distortion of the frequency is 0.1% (constant). Further, the temperature of the rubber part 562 at the time of measurement is maintained at 20 ° C.

  As described above, when the frequency of the rubber part 562 is higher than the boundary frequency f, the rubber part 562 made of a rubber elastic body exhibits a glass-like property instead of a rubber-like property. Therefore, when the development is performed, the frequency does not become higher than the boundary frequency f so that the function of the rubber portion 562 made of a rubber elastic body is appropriately exerted (the frequency is the boundary vibration). The frequency needs to be controlled (so that it is smaller than the number f).

  The frequency control is realized by controlling the rotation speed of the developing roller 510. That is, as described above, the vibration frequency of the rubber portion 562 is a value obtained by dividing the moving speed of the surface when the developing roller 510 rotates by the circumferential pitch of the developing roller 510 of the groove portion 512. The frequency is proportional to the moving speed. Since the moving speed is proportional to the rotation speed of the developing roller 510, the vibration frequency is proportional to the rotating speed of the developing roller 510. That is, if the rotation speed of the developing roller 510 is increased, the vibration frequency is increased, and if the rotation speed is decreased, the vibration frequency is decreased.

  Accordingly, the rotational speed of the developing roller 510 during development (the rotational speed during development) is such that the frequency (that is, the value obtained by dividing the moving speed by the pitch) is smaller than the boundary frequency. If the rotational speed, in other words, the moving speed is a rotational speed that is smaller than the product of the pitch and the boundary frequency, a rubber portion made of a rubber elastic body when developing is performed. It is possible to maintain 562 in a rubber-like nature and to appropriately exhibit the function of the rubber portion 562.

  In this embodiment, as described above, the moving speed, the pitch, and the boundary frequency when development is performed are about 320 mm / s, about 113 μm, and about 6700 Hz, respectively. Is 757.1 mm / s. Therefore, when the development is performed, the moving speed of the surface of the developing roller 510 when the developing roller 510 rotates at the developing rotational speed is smaller than the product. In other words, the controller 100 according to the present embodiment is configured so that the rotation speed during development of the developing roller 510 is equal to the pitch and the boundary frequency in order to appropriately exert the function of the rubber portion 562. The rotation of the developing roller 510 is controlled so that the rotation speed becomes smaller than the product of.

  However, as described in the section of the problem to be solved by the invention, when development is performed in a state where the rubber portion 562 exhibits rubber-like properties, due to tackiness of the rubber portion 562 based on the rubber-like properties, Filming occurs in the rubber part 562.

  FIG. 10 is a schematic diagram showing a state in which filming has occurred in the rubber part 562. As described above, the rubber portion 562 according to the present embodiment has a longitudinal direction along the axial direction of the developing roller 510, and one end in the short direction (that is, the tip 560a of the regulating blade 560). The developing roller 510 is in contact with the surface of the developing roller 510 so as to face the upstream side in the rotational direction of the developing roller 510. In addition, the contact portion 562a of the rubber portion 562 that contacts the surface of the developing roller 510 is separated from the one end (tip 560a) in the short direction. In such a configuration, the toner flows into the portion D shown in FIG. 10 (the portion between the rubber portion 562 and the developing roller 510) with the rotation of the developing roller 510. Therefore, the diagonal portion of the rubber portion 562 in FIG. Filming occurs in the portion where the mark is applied.

  When the filming becomes noticeable, the image quality of the image that is developed and finally formed on the medium is deteriorated.

  Therefore, the controller 100 according to the present embodiment temporarily performs control for shaking off the filming from the rubber part 562 during the start-up control and the start-down control.

  Here, what kind of control is the control for shaking off the filming from the rubber part 562 will be described. As already described, the rubber part 562 exhibits a rubber-like property or a glass-like property depending on its frequency. When the vibrating rubber part 562 exhibits a glass-like property, the tackiness based on the rubber-like property of the rubber part 562 is reduced, and filming is easily separated from the rubber part 562. Further, when the rubber portion 562 exhibits a glass-like property, the rubber portion 562 exhibits a harder property than when the rubber portion 562 exhibits a rubber-like property. Therefore, the developing roller 510 has a rubber portion at the contact portion 562a. The vibration generated in the contact portion 562a when sliding with respect to the 562 is easily transmitted to the portion where the slanted filming exists in FIG. 10 (conversely, the rubber portion 562 exhibits rubber-like properties). (Sometimes, the vibration generated in the contact portion 562a is absorbed by the rubber portion 526 in the process of being transmitted to the portion where filming exists, and thus is difficult to be transmitted to the portion). For these reasons, when the vibrating rubber part 562 exhibits a glass-like property, the vibration is effectively transmitted to the filming that is easily separated, so that the filming is appropriately shaken from the rubber part 562. It will be dropped.

  On the other hand, as described above, the rotation speed of the developing roller 510 is such that the vibration frequency (that is, the value obtained by dividing the movement speed by the pitch) is smaller than the boundary frequency, in other words, the movement. If the speed is a rotational speed that is smaller than the product of the pitch and the boundary frequency, the vibrating rubber portion 562 exhibits rubber-like properties, and conversely, the rotational speed of the developing roller 510 is the vibration speed. The rotational speed at which the number (ie, the value obtained by dividing the moving speed by the pitch) is greater than the boundary frequency, in other words, the moving speed is greater than the product of the pitch and the boundary frequency. If it becomes the rotational speed which becomes, the rubber | gum part 562 which vibrates shows a glass-like property. Accordingly, if the rotation of the developing roller 510 is controlled so that the rotational speed of the developing roller 510 is a rotational speed at which the moving speed is larger than the product of the pitch and the boundary frequency, the filming can be performed on the rubber. It is possible to appropriately shake off the part 562.

  In view of this, in the present embodiment, in order to shake the filming off from the rubber portion 562, the controller 100 temporarily controls the developing roller 510 during the start-up control and the start-down control. The rotation of the developing roller 510 is controlled so that the rotational speed becomes a rotational speed at which the moving speed is larger than the product of the pitch and the boundary frequency.

  More specifically, in the start-up control, the controller 100 starts the rotation of the developing roller 510 and then determines the rotation speed of the developing roller 510 based on whether the moving speed is the pitch and the boundary frequency. The filming is shaken off from the rubber portion 562 by increasing the rotation speed to be greater than the product (hereinafter also referred to as the first rotation speed V1). After that (that is, after the rotational speed of the developing roller 510 reaches the first rotational speed V1), the controller 100 determines the rotational speed of the developing roller 510, the moving speed is the pitch and the boundary frequency. The rotation speed is lowered to a rotational speed (hereinafter also referred to as a second rotational speed V2) that is smaller than the product of and the developing roller 510 that rotates at the second rotational speed V2 develops the latent image. That is, the controller 100 raises the rotation speed of the developing roller 510 to the first rotation speed V1 before performing the development that does not require the function of the rubber part 562 made of a rubber elastic body, so that filming is performed on the rubber part. Shake off from 562. Then, the latent image is developed by the developing roller 510 with the filming properly removed.

  Further, the controller 100 has a rotational speed at which the moving speed is smaller than the product of the pitch and the boundary frequency (hereinafter referred to as a fifth rotational speed V5. In the present embodiment, the fifth rotational speed V5 is used. Is equal to the second rotation speed V2), the developing roller 510 rotating at the same time develops the latent image, and after the development of the developing roller of the latent image is finished, the developing roller The rotational speed of 510 is the rotational speed at which the moving speed is greater than the product of the pitch and the boundary frequency (hereinafter also referred to as a fourth rotational speed V4. In the present embodiment, the fourth rotational speed V4. Is equal to the first rotation speed V1), and thereafter (that is, after the rotation speed of the developing roller 510 reaches the fourth rotation speed V4), the rotation of the developing roller 510 is stopped. That is, the controller 100 increases the rotational speed of the developing roller 510 to the fourth rotational speed V4 after performing the development that does not require the function of the rubber portion 562 made of a rubber elastic body, so that the filming generated during the development is performed. Is shaken off from the rubber part 562.

  Although the second rotation speed V2 and the fifth rotation speed V5 are the rotation speeds at which the moving speed of the surface of the developing roller 510 is about 320 mm / s, the present embodiment has already been described. The first rotation speed V1 and the fourth rotation speed V4 are rotation speeds (the second rotation speed V2 and the fifth rotation speed V5 of which the moving speed of the surface of the developing roller 510 is about 800 mm / s). 2.5 times). As described above, the product of the pitch and the boundary frequency is 757.1 mm / s. Therefore, when the first rotation speed V1 and the fourth rotation speed V4 are such rotation speeds, the filming is performed on the rubber portion 562. It can be shaken off appropriately. However, the value of the rotation speed is not limited to these numerical values, and can be appropriately determined according to the value of the pitch or the boundary frequency.

<<< Specific Example of Start-up Control of Developing Roller 510 >>>
Next, a specific example of the start-up control of the developing roller 510 will be described with reference to FIG. FIG. 11 is a schematic diagram showing changes in the rotational speed of the developing roller 510 when the start-up control of the developing roller 510 is executed. Time is plotted on the horizontal axis and the rotational speed of the developing roller 510 is plotted on the vertical axis. Yes. In this section, reference is also made to the development start timing for starting development of a latent image and the application start timing for starting application of a development bias for developing the latent image.

  In FIG. 11, when the time on the horizontal axis is 0, the developing roller 510 is stopped. Then, at time ta1, the controller 100 gives a command for rotating the developing roller 510 at the first rotation speed V1 to shake off the filming from the rubber part 562. The rotation is started, and the rotation speed of the developing roller 510 is increased toward the first rotation speed V1. The rotation speed of the developing roller 510 gradually increases, and from 0, the rotation speed at which the moving speed becomes equal to the product of the pitch and the boundary frequency (hereinafter referred to as the third rotation speed V3) is a time ta2. The first rotation speed V1 is reached at time ta3.

  Next, at the time ta4, the controller 100 rotates the developing roller 510 at the second rotation speed V2 (that is, the developing rotation speed) in order to appropriately perform the function of the rubber portion 562 when performing the development. A command is given to the developing roller 510 to lower the rotational speed of the developing roller 510 toward the second rotational speed V2. The rotation speed of the developing roller 510 gradually decreases, and from the first rotation speed V1 to the second rotation speed V2 at time ta6 via the third rotation speed V3 at time ta5. In the present embodiment, the time from the time ta3 to the time ta4, that is, the time during which the developing roller 510 is rotating at the first rotation speed V1, is the time that the developing roller 510 makes one round (this embodiment In this case, the time ta4 is set to be longer than about 70 msec).

  In addition, after the rotational speed of the developing roller 510 reaches the third rotational speed V3 at the time ta5, the controller 100, more precisely, after the rotational speed of the developing roller 510 reaches the third rotational speed V3. The portion of the surface of the developing roller 510 that the rubber portion 562 contacts when the rotational speed of the developing roller 510 reaches the third rotational speed V3 is increased with the further rotation of the developing roller 510. Application of a developing bias to the developing bias applying unit 121 is started at a time ta8 after a time when moving to a position facing the photoconductor 20 has elapsed (this time is indicated by a time ta7 in FIG. 11). Let

  The reason why the development bias application start timing is set in this way will be described. As described above, the controller 100 rotates the developing roller 510 at the first rotation speed V1 from time ta3 to time ta4 in order to shake the filming off from the rubber portion 562. Strictly speaking, the rubber portion 562 Since the period of glassy properties is from time ta2 to time ta5, filming is shaken off from the rubber part 562 during the period. By the way, when the filming is shaken off from the rubber part 562, the filming falls in the direction of gravity and is appropriately collected by the toner container 530, but a part of the filming is transferred to the developing roller 510. It adheres to the surface of the developing roller 510. The filming adhering to the surface moves with the rotation of the developing roller 510 from the contact position where the rubber part 562 contacts, and eventually reaches the contact position where the toner supply roller 550 comes into contact. Then, it is peeled off by the toner supply roller 550 and appropriately recovered by the toner container 530. However, when the filming adhered to the surface of the developing roller 510 moves from the contact position as the developing roller 510 rotates and reaches a position facing the photoconductor 20, the developing bias is applied. If so, the filming may move to the photoconductor 20. When the filming moves to the photoconductor 20, proper recovery by the filming toner container 530 is hindered.

  In order to avoid such a problem, the controller 100 according to the present embodiment avoids such a problem after the rotation speed of the developing roller 510 reaches the third rotation speed V3 at time ta5 (that is, filming is performed on the developing roller). When the rotation speed of the developing roller 510 among the surfaces of the developing roller 510 reaches the third rotation speed V3 (time ta5) after the last adhesion to the surface of 510, the rubber portion 562 The time during which the abutting portion moves to a position facing the photoconductor 20 with further rotation of the developing roller 510 (that is, the filming that has finally adhered to the surface is from the abutting position to the developing roller 510. After the time (time ta7) when the time required to move with rotation and reach the position facing the photoconductor 20 (time ta7) has passed, the time ta8 A developing bias applying unit 121 to start the application of the developing bias.

  Then, after the application of the developing bias is started at time ta8, the controller 100 waits for a time for the developing bias to be sufficiently stabilized, and at time ta9, the controller 100 transfers the latent image to the developing roller 510 that rotates at the second rotation speed V2. Let development occur. That is, at time ta9, the latent image on the photoconductor 20 faces the developing roller 510, and development of the latent image is started.

<<< Specific Example of Controlling Lowering of Developing Roller 510 >>>
Next, a specific example of the lowering control of the developing roller 510 will be described with reference to FIG. FIG. 12 is a schematic diagram showing changes in the rotation speed of the developing roller 510 when the control for lowering the developing roller 510 is executed. Time is plotted on the horizontal axis and the rotational speed of the developing roller 510 is plotted on the vertical axis. Yes. In this section, the development end timing for ending the development of the latent image and the application end timing for ending the application of the developing bias are also referred to.

  In FIG. 12, when the time on the horizontal axis is 0, the developing roller 510 rotates at the fifth rotation speed V5, and the latent image is developed. In other words, the controller 100 causes the developing roller 510 that rotates at the fifth rotation speed V5 at which the function of the rubber portion 562 is appropriately exhibited at the time of executing development to develop the latent image.

  Then, the controller 100 finishes developing the latent image at time tb1, and then rotates the developing roller 510 at the fourth rotational speed V4 to shake off the filming from the rubber part 562 at time tb2. A command is given to the developing roller 510 to increase the rotational speed of the developing roller 510 toward the fourth rotational speed V4. The rotation speed of the developing roller 510 gradually increases, and from the fifth rotation speed V5, the third rotation speed V3 at which the moving speed is equal to the product of the pitch and the boundary frequency is passed at time tb4. Thus, the fourth rotational speed V4 is reached at time tb5.

  Here, the application end timing for ending the application of the developing bias will be described. In the present embodiment, considering the possibility that the application end timing may precede the development end timing due to timing control errors, the development end timing and the application end timing are not set to the same timing. The application end timing is delayed from the development end timing. That is, the controller 100 ends the development of the latent image at time tb1, and then ends the application of the developing bias by the developing bias applying unit 121. Furthermore, the controller 100, more precisely, before the rotation speed of the developing roller 510 reaches the third rotation speed V3 at time tb4, more precisely, after the rotation speed of the developing roller 510 reaches the third rotation speed V3. The portion of the surface of the developing roller 510 that the rubber portion 562 contacts when the rotational speed of the developing roller 510 reaches the third rotational speed V3 is increased with the further rotation of the developing roller 510. The application of the developing bias is terminated at time tb3 before the time when the time to move to the position facing the photoconductor 20 has elapsed (this time is indicated by time tb6 in FIG. 12).

  That is, the controller 100 reaches the position where the above-described problem, that is, the filming attached to the surface of the developing roller 510 moves from the contact position with the rotation of the developing roller 510 and faces the photoconductor 20. When the developing bias is applied, the rotation speed of the developing roller 510 is set to the third rotation speed V3 at time tb4 in order to avoid the problem that the filming moves to the photoconductor 20. (That is, after filming first adheres to the surface of the developing roller 510), the rotation speed of the developing roller 510 among the surfaces of the developing roller 510 becomes the third rotation speed V3. When this occurs (time tb4), the portion where the rubber portion 562 contacts is in a position facing the photoconductor 20 as the developing roller 510 further rotates. The moving time (that is, the time from when the filming that first adheres to the surface moves from the contact position to the position facing the photoconductor 20 as the developing roller 510 rotates) has passed. Prior to the time (time tb6), the application of the developing bias is terminated at time tb3.

  Next, after the rotational speed of the developing roller 510 reaches the fourth rotational speed V4 at time tb5, the controller 100 starts to stop the rotation of the developing roller 510 by decreasing the rotational speed of the developing roller 510 at time tb7. Here, when the controller 100 according to the present embodiment stops the rotation of the developing roller 510, after the rotational speed of the developing roller 510 reaches the third rotational speed V3 at time tb8, the surface of the developing roller 510 is Of these, the portion where the rubber portion 562 contacts when the rotation speed of the developing roller 510 reaches the third rotation speed V3 is the contact where the toner supply roller 550 contacts with the further rotation of the developing roller 510. The rotation is stopped at time tb12 after the time when the time for moving to the position has elapsed (the time is indicated by time tb10 in FIG. 12).

  The reason why the developing roller 510 is stopped in this way will be described. As described above, the controller 100 rotates the developing roller 510 at the fourth rotational speed V4 from time tb5 to time tb7 in order to shake off the filming from the rubber portion 562. Strictly speaking, the rubber portion 562 Since the period of the glassy property is from time tb4 to time tb8, filming is shaken off from the rubber portion 562 during the period. As described above, when filming is shaken off from the rubber portion 562, a part of the filming moves to the developing roller 510 and adheres to the surface of the developing roller 510. Further, the filming adhering to the surface moves with the rotation of the developing roller 510 from the contact position where the rubber portion 562 contacts, and eventually reaches the contact position where the toner supply roller 550 contacts, and reaches the contact position. Then, it is peeled off by the toner supply roller 550 and appropriately recovered by the toner container 530. Filming that has been shaken off from time tb4 to time tb8 and adhered to the surface is completely removed by the toner supply roller 550 at the contact position before the developing roller 510 stops at time tb12. It is desirable that

  Therefore, in consideration of this, the controller 100 according to the present embodiment stops the rotation of the developing roller 510 after the rotation speed of the developing roller 510 reaches the third rotation speed V3 at time tb8. When the rotation speed of the developing roller 510 of the surface of the developing roller 510 reaches the third rotational speed V3 (that is, after filming has finally adhered to the surface of the developing roller 510) ( At the time tb8), the portion where the rubber portion 562 contacts moves to the contact position where the toner supply roller 550 contacts with the further rotation of the developing roller 510 (that is, the filming that has finally adhered to the surface is When the time from the contact position to the contact position after the development roller 510 rotates is reached (time tb10) Later than, stopping the rotation at the time TB12.

  Then, after starting to stop the rotation of the developing roller 510 at time tb7, the controller 100 stops the developing roller 510 with sufficient time to realize the above-described matters. More specifically, the controller 100 gives a command for rotating the developing roller 510 at the fifth rotation speed V5 (that is, the developing rotation speed) at the time tb7 to the developing roller 510, thereby developing the developing roller 510. The rotational speed of the roller 510 is lowered toward the second rotational speed V2. The rotation speed of the developing roller 510 gradually decreases, and from the fourth rotation speed V4 to the fifth rotation speed V5 at time tb9 via the third rotation speed V3 at time tb8. Then, after the developing roller 510 is rotated at the fifth rotation speed V5 for a while, a command for stopping the developing roller 510 is given to the developing roller 510 at time tb11, and the rotation speed of the developing roller 510 is increased. Is lowered toward 0. The rotational speed of the developing roller 510 gradually decreases and becomes 0 at time tb12 from the fifth rotational speed V5 (the developing roller 510 stops). In the present embodiment, the time from the time tb5 to the time tb7, that is, the time during which the developing roller 510 is rotating at the fourth rotational speed V4, is the time that the developing roller 510 makes one round (this embodiment In this case, the time tb7 is set to be longer than about 70 msec.

=== Effectiveness of Printer 10 According to the Present Embodiment ===
As described above, in the printer 10 according to the present embodiment, the controller 100 starts the rotation of the developing roller 510 and then changes the rotational speed of the developing roller 510 with the moving speed being the pitch and the boundary frequency. After the rotational speed of the developing roller 510 reaches the first rotational speed V1, the rotational speed of the developing roller 510 is changed from the pitch to the pitch. Filming becomes significant because the developing roller 510 that rotates at the second rotation speed V2 is lowered to a second rotation speed V2 that is smaller than the product of the boundary frequency and develops the latent image. First, the filming is appropriately shaken off from the rubber part 562. Therefore, deterioration of the image quality of the image that is developed and finally formed on the medium is appropriately prevented.

  Further, in the printer 10 according to the present embodiment, the controller 100 changes the rotation speed of the developing roller 510 to the first rotation speed V1 after the rotation speed of the developing roller 510 reaches the first rotation speed V1. From the third rotational speed V3 at which the moving speed becomes equal to the product, and then the second rotational speed V2 is lowered, and the rotational speed of the developing roller 510 reaches the third rotational speed V3. The development bias application by the development bias application unit 121 is started. More precisely, after the rotation speed of the developing roller 510 reaches the third rotation speed V3, the rotation speed of the front developing roller 510 on the surface of the developing roller 510 reaches the third rotation speed V3. The application of the developing bias is started after the time when the portion in contact with the rubber portion 562 moves to the position facing the photoconductor 20 with the further rotation of the developing roller 510 has elapsed. Therefore, the possibility that the filming moves to the photoconductor 20 is reduced, and the filming is appropriately collected by the toner container 530. If the development bias application by the development bias application unit 121 is started after the rotation speed of the developing roller 510 reaches the third rotation speed V3, the application of the development bias is started before the time point. Even if the above-mentioned effect is obtained (that is, the effect that the filming is properly recovered by the toner container 530), the above-mentioned effect is generated after considering that the generation of the effect is complete. It is desirable to start applying the development bias.

  In the printer 10 according to the present embodiment, the controller 100 causes the latent image to be transferred to the developing roller 510 that rotates at the fifth rotation speed V5 in which the moving speed is smaller than the product of the pitch and the boundary frequency. After the development of the latent image is completed, the rotational speed of the developing roller 510 is increased to a fourth rotational speed V4 where the moving speed is greater than the product, and the developing roller 510 is rotated. After the speed reaches the fourth rotation speed V4, the rotation of the developing roller 510 is stopped. Therefore, the filming is appropriately shaken off from the rubber part 562 before the filming becomes remarkable. Therefore, deterioration of the image quality of the image that is developed and finally formed on the medium is appropriately prevented.

  Further, in the printer 10 according to the present embodiment, after the controller 100 finishes developing the latent image, the rotation speed of the developing roller 510 is changed from the fifth rotation speed V5 to the moving speed. Development bias applied by the developing bias applying unit 121 before the rotation speed of the developing roller 510 reaches the third rotation speed V3. The application of was decided to be terminated. More precisely, when the rotation speed of the developing roller 510 reaches the third rotation speed V3 and the rotation speed of the developing roller 510 on the surface of the developing roller 510 reaches the third rotation speed V3, the rubber is used. The application of the developing bias is terminated before the time when the portion in contact with the portion 562 moves to the position facing the photoconductor 20 with the further rotation of the developing roller 510 has elapsed. Therefore, the possibility that the filming moves to the photoconductor 20 is reduced, and the filming is appropriately collected by the toner container 530. Note that if the application of the developing bias is terminated before the time point, the effect (that is, the effect that the filming is appropriately collected by the toner container 530) is produced. In order to surely generate it, it is desirable to end the application of the developing bias before the rotational speed of the developing roller 510 reaches the third rotational speed V3.

  Further, in the printer 10 according to the present embodiment, the controller 100 causes the developing roller 510 to stop when the developing roller 510 stops rotating after the rotational speed of the developing roller 510 reaches the fourth rotational speed V4. After the rotation speed reaches the third rotation speed V3, the portion of the surface of the developing roller 510 that contacts the rubber portion 562 when the rotation speed of the developing roller 510 reaches the third rotation speed V3 is developed. Since the rotation is stopped after a time when the toner supply roller 550 moves to a position where the toner supply roller 550 contacts with the further rotation of the roller 510, the filming is performed before the developing roller 510 stops. In addition, the toner is appropriately peeled off by the toner supply roller 550.

=== Method for Manufacturing Developing Roller 510 ===
Here, a method of manufacturing the developing roller 510 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.

  First, as shown in FIG. 13A, a pipe material 600 as a base material of the developing roller 510 is prepared. 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 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, the pipe material 600 into which the flange 604 is press-fitted is subjected to a rolling process. 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). In the through-feed rolling, as the round dies 650 and 652 rotate, 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 shown. Protrusions 650 a and 652 a for forming grooves 680 are provided on the surfaces of the round dies 650 and 652, and the grooves 680 are formed in the pipe material 600 by deforming the pipe material 600 by the protrusions 650 a and 652 a. Is formed.

  Then, after the rolling process is finished, the surface of the central portion 510a is plated. In the present embodiment, electroless Ni—P plating is used as the plating, but is not limited to this, and for example, hard chrome plating or electroplating may be used.

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

  In the above embodiment, an 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, such as a full color laser beam printer, a monochrome laser beam printer, a copying machine, and a facsimile. The present invention can be applied to various image forming apparatuses.

  Further, the printer 10 is set with a use temperature range (for example, a temperature range in which it is guaranteed that no problem occurs when the printer 10 is used). Is used, the rotation speed of the developing roller 510 is increased to the first rotation speed V1 or the fourth rotation speed V4 in which the moving speed is larger than the product of the pitch and the boundary frequency. Is desirable.

  It is known that the value of the boundary frequency fluctuates slightly according to a change in the temperature of the rubber part 562. Therefore, the value of the boundary frequency slightly changes depending on the temperature within which the printer 10 is used. Therefore, when the rotation speed of the developing roller 510 is set to a predetermined rotation speed, the predetermined rotation speed is determined so that the moving speed is equal to the pitch and the boundary frequency in a part of the temperature range within the use temperature range. In the other part of the temperature range within the operating temperature range, the predetermined rotational speed is greater than the product of the moving speed by the pitch and the boundary frequency. There may be a case where the rotation speed becomes smaller.

  Then, the rotational speed of the developing roller 510 is set to a first rotational speed V1 or a fourth rotational speed at which the moving speed is larger than the product of the pitch and the boundary frequency in a part of the temperature range within the operating temperature range. Even if the speed is increased to V4, the above-described effect (that is, the effect of appropriately preventing the deterioration of the image quality of the image) is sufficiently produced. However, the rotation speed of the developing roller 510 is set to the entire temperature within the use temperature range. In the range, it is desirable that the moving speed is increased to a first rotational speed V1 or a fourth rotational speed V4 that is greater than a product of the pitch and the boundary frequency.

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

  FIG. 15 is an explanatory diagram showing an external configuration of the image forming system. The image forming system 700 includes a computer 702, a display device 704, a printer 706, an input device 708, and a reading device 710. In this embodiment, the computer 702 is housed in a mini-tower type housing, but is not limited thereto. The display device 704 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 706, the printer described above is used. In this embodiment, the input device 708 uses a keyboard 708A and a mouse 708B, but is not limited thereto. In this embodiment, the reading device 710 uses a flexible disk drive device 710A and a CD-ROM drive device 710B. However, the reading device 710 is not limited to this. For example, an MO (Magneto Optical) disk drive device or a DVD (Digital Versatile) is used. Disk) etc. may be used.

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

  In the above description, the example in which the printer 706 is connected to the computer 702, the display device 704, the input device 708, and the reading device 710 to configure the image forming system has been described. However, the present invention is not limited to this. Absent. For example, the image forming system may include a computer 702 and a printer 706, and the image forming system may not include any of the display device 704, the input device 708, and the reading device 710. For example, the printer 706 may have a part of the functions or mechanisms of the computer 702, the display device 704, the input device 708, and the reading device 710. As an example, the printer 706 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.

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

FIG. 2 is a diagram illustrating main components constituting the printer. FIG. 2 is a block diagram illustrating a controller of the printer 10 in FIG. 1. It is a conceptual diagram of a developing device. It is sectional drawing which showed the main components of the image development apparatus. 3 is a schematic perspective view of a developing roller 510. FIG. 2 is a schematic front view of a developing roller 510. FIG. FIG. 6 is a schematic diagram showing a cross-sectional shape of a groove part 512. It is an expansion schematic diagram of FIG. It is the graph which showed the relationship between the frequency of the rubber part 562, a storage elastic modulus, a loss elastic modulus, and a loss tangent. FIG. 6 is a schematic diagram showing a state where filming has occurred in a rubber part 562; FIG. 6 is a schematic diagram showing a change in the rotation speed of the developing roller 510 when the start-up control of the developing roller 510 is executed. FIG. 6 is a schematic diagram showing a change in the rotation speed of the developing roller 510 when the control for lowering the developing roller 510 is executed. 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. 1 is an explanatory diagram showing an external configuration of an image forming system. FIG. 16 is a block diagram illustrating a configuration of the image forming system illustrated in FIG. 15.

Explanation of symbols

10 Printer, 10a Printer body, 20 Photoconductor, 30 Charging unit,
40 exposure unit, 50 YMCK development 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 member, 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 controller, 101 main controller,
102 unit controller, 112 interface,
113 image memory, 121 developing bias application unit,
510 developing roller, 510a central portion, 512 groove portion,
512a first groove portion, 512b second groove portion, 513 side surface, 514 bottom surface,
515 Top surface, 520 Top seal, 522 Top seal support sheet metal,
524 upper seal urging member, 530 toner container,
530a first toner container, 530b second toner container, 540 housing,
542 Upper housing part, 544 Lower housing part, 545 Partition wall,
550 toner supply roller, 560 regulating blade,
560a tip, 562 rubber part, 562a contact part, 564 rubber support part,
564a thin plate, 564b thin plate support, 564d one end in the short direction,
564e, the other end in the short direction, 570 blade backing member, 572 opening,
600 pipe material, 602 flange press-fit part,
604 flange, 650 round die, 650a convex, 652 round die,
652a convex portion, 680 groove, 700 image forming system, 702 computer,
704 display device, 706 printer, 708 input device, 708A keyboard,
708B mouse, 710 reader,
710A flexible disk drive device,
710B CD-ROM drive device,
802 internal memory, 804 hard disk drive unit,
T Toner

Claims (11)

(A) an image carrier for carrying a latent image;
(B) A rotatable developer carrying member having regularly arranged recesses on the surface for carrying the developer, and developing the latent image with the developer carried on the developer carrying member. A developer carrier for carrying out
(C) a contact member made of a rubber elastic body that is in contact with the surface of the developer carrier and vibrates with the rotation of the developer carrier;
(D) After starting the rotation of the developer carrier, the rotation speed of the developer carrier is
The moving speed of the surface when the developer carrying member rotates is a loss obtained by dividing the pitch of the concave portion in the circumferential direction of the developer carrying member and the loss elastic modulus of the contact member by the storage elastic modulus. The first rotational speed that is greater than the product of the frequency of the tangent member when the tangent is maximum,
Up to
After the rotation speed of the developer carrier becomes the first rotation speed, the rotation speed of the developer carrier is lowered to a second rotation speed at which the moving speed is smaller than the product,
A controller that causes the developer carrying member rotating at the second rotation speed to develop the latent image;
An image forming apparatus having (E). The image forming apparatus according to claim 1,
A development bias application unit for applying a development bias to the developer carrier for developing the latent image;
The controller is
After the rotation speed of the developer carrier becomes the first rotation speed, the rotation speed of the developer carrier is changed from the first rotation speed to the third rotation speed at which the moving speed is equal to the product. Through to the second rotational speed, and
An image forming apparatus, wherein the development bias application unit starts applying the development bias after the rotation speed of the developer carrying member reaches the third rotation speed. The image forming apparatus according to claim 2.
The controller is
When the rotation speed of the developer carrying body becomes the third rotation speed, the rotation speed of the developer carrying body of the surface of the developer carrying body reaches the third rotation speed. When a portion of the contact member that abuts moves to a position facing the image carrier as the developer carrier further rotates,
After
An image forming apparatus, wherein the development bias application unit starts application of the development bias. (A) an image carrier for carrying a latent image;
(B) A rotatable developer carrying member having regularly arranged recesses on the surface for carrying the developer, and developing the latent image with the developer carried on the developer carrying member. A developer carrier for carrying out
(C) a contact member made of a rubber elastic body that is in contact with the surface of the developer carrying member and vibrates with the rotation of the developer carrying member;
(D) The moving speed of the surface when the developer carrying member rotates is the storage elastic modulus of the pitch of the concave portion in the circumferential direction of the developer carrying member and the loss elastic modulus of the contact member. The fifth rotational speed, which is smaller than the product of the frequency of the corresponding contact member when the divided loss tangent is maximum,
Developing the latent image on the developer carrying member rotating at
After completing the development of the latent image, the rotational speed of the developer carrier is increased to a fourth rotational speed at which the moving speed is greater than the product,
A controller that stops the rotation of the developer carrier after the rotation speed of the developer carrier reaches the fourth rotation speed;
An image forming apparatus having (E). The image forming apparatus according to claim 4.
A development bias application unit for applying a development bias to the developer carrier for developing the latent image;
The controller is
After completing the development of the latent image, the rotation speed of the developer carrier is changed from the fifth rotation speed to the fourth rotation speed through a third rotation speed at which the moving speed is equal to the product. Increase to rotational speed, and
When the rotation speed of the developer carrying body becomes the third rotation speed, the rotation speed of the developer carrying body of the surface of the developer carrying body reaches the third rotation speed. When a portion of the contact member that abuts moves to a position facing the image carrier as the developer carrier further rotates,
Before
An image forming apparatus, wherein application of the development bias by the development bias application unit is terminated. The image forming apparatus according to claim 5.
Before the rotation speed of the developer carrier becomes the third rotation speed,
An image forming apparatus, wherein application of the development bias by the development bias application unit is terminated. The image forming apparatus according to any one of claims 4 to 6,
A stripping member for contacting the surface of the developer carrier and stripping the developer from the developer carrier;
The controller is
When the rotation of the developer carrier is stopped after the rotation speed of the developer carrier reaches the fourth rotation speed,
When the rotation speed of the developer carrying body becomes the third rotation speed, the rotation speed of the developer carrying body of the surface of the developer carrying body reaches the third rotation speed. When the time when the part where the contact member abuts moves to a position where the stripping member contacts with the further rotation of the developer carrier has elapsed,
After
An image forming apparatus, wherein the rotation is stopped. Computer and
An image forming apparatus connectable to the computer, having an image carrier for carrying a latent image and a regularly arranged recess on the surface, and a rotatable developer carrying for carrying the developer A developer carrying body for developing the latent image with the developer carried on the developer carrying body, and abutting against the surface of the developer carrying body, The contact member made of a rubber elastic body that vibrates with rotation, and the rotation speed of the developer carrying body after starting the rotation of the developer carrying body, the rotation speed of the developer carrying body when the developer carrying body rotates Vibration speed of the contact member when the loss tangent obtained by dividing the circumferential pitch of the developer carrier and the loss elastic modulus of the contact member by the storage elastic modulus is maximum. The developer loading is increased to a first rotational speed, which is greater than the product of the number and After the rotation speed reaches the first rotation speed, the rotation speed of the developer carrier is lowered to a second rotation speed at which the moving speed is smaller than the product, and the second rotation speed is decreased. A controller for causing the rotating developer carrying member to develop the latent image;
An image forming system comprising: Computer and
An image forming apparatus connectable to the computer, having an image carrier for carrying a latent image and a regularly arranged recess on the surface, and a rotatable developer carrying for carrying the developer A developer carrying body for developing the latent image with the developer carried on the developer carrying body, and abutting against the surface of the developer carrying body, The contact member made of a rubber elastic body that vibrates with rotation, the moving speed of the surface when the developer carrier rotates, and the pitch of the concave portion in the circumferential direction of the developer carrier, The developer carrying member that rotates at a fifth rotational speed that is smaller than the product of the vibration frequency of the corresponding contact member when the loss tangent obtained by dividing the loss elastic modulus of the contact member by the storage elastic modulus is maximum. After developing the latent image and finishing the development of the latent image, the developer bearing The rotational speed of the developer is increased to a fourth rotational speed at which the moving speed is greater than the product, and after the rotational speed of the developer carrier reaches the fourth rotational speed, the developer carrier A controller for stopping rotation of the image forming apparatus,
An image forming system comprising: A rotatable developer carrying member having a concave portion regularly arranged on the surface for carrying the developer, the latent image carried on the image carrier by the developer carried on the developer carrying member. A developer carrier for developing an image,
The rotation speed of the developer carrier is
The speed of movement of the surface when the developer carrying member rotates is in contact with the pitch of the concave portion in the circumferential direction of the developer carrying member and the surface of the developer carrying member. It becomes larger than the product of the frequency of the contact member when the loss tangent obtained by dividing the loss elastic modulus of the contact member made of a rubber elastic body that vibrates with the rotation of the carrier by the storage elastic modulus becomes maximum. First rotation speed,
Step up to,
Lowering the rotation speed of the developer carrier to a second rotation speed at which the moving speed is smaller than the product after the rotation speed of the developer carrier becomes the first rotation speed; ,
Causing the developer carrying member rotating at the second rotation speed to develop the latent image;
An image forming method comprising: A rotatable developer carrying member having a concave portion regularly arranged on the surface for carrying the developer, the latent image carried on the image carrier by the developer carried on the developer carrying member. A developer carrier for developing an image,
The speed of movement of the surface when the roller rotates is in contact with the pitch of the concave portion in the circumferential direction of the developer carrier and the surface of the developer carrier so that the developer carrier rotates. A fifth rotational speed that is smaller than the product of the frequency of the contact member when the loss tangent obtained by dividing the loss elastic modulus of the contact member made of a rubber elastic body that vibrates with the storage elastic modulus becomes the maximum,
Developing the latent image on the developer carrying member rotating at
After completing the development of the latent image, increasing the rotational speed of the developer carrying member to a fourth rotational speed at which the moving speed is greater than the product;
Stopping the rotation of the developer carrier after the rotation speed of the developer carrier reaches the fourth rotation speed;
An image forming method comprising:

Images