JP2007147853A - Toner particle carrying roller, developing device, image forming apparatus, and image formation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a toner particle carrying roller capable of suitably suppressing retention of toner particles. <P>SOLUTION: The toner particles carrying roller for carrying toner particles is provided with a flat bottom and a side face adjacent to the bottom and has a recessed part having roundness of which the radius of curvature is a half and more of a volume average grain size of a toner particle is formed on the surface of a boundary part between the bottom and the side face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

On the surface of a toner particle carrying roller provided in an image forming apparatus such as a laser beam printer, a flat bottom surface and a recess having a side surface adjacent to the bottom surface are provided in order to properly carry toner particles. Yes.
JP-A-1-102486 JP-A-5-142950

  By the way, toner particles, in particular, fine powder toner particles may stay at the boundary between the bottom surface and the side surface.

  The present invention has been made in view of such problems, and an object of the present invention is to realize a toner particle carrying roller in which retention of toner particles is appropriately suppressed.

  A main present invention is a toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, and a radius of curvature at a boundary portion between the bottom surface and the side surface. A toner particle carrying roller having a concave portion provided with a roundness which is half or more of a volume average particle diameter of the surface thereof.

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

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

  A toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, and a radius of curvature at a boundary portion between the bottom surface and the side surface, the volume average particle diameter of the toner particles A toner particle carrying roller having a concave portion provided with a roundness which is half or more of the surface.

On the other hand, a toner particle carrying roller for carrying toner particles, which is a concave portion having a flatly inclined portion and having a first side surface and a second side surface facing each other, the lower portion of the concave portion The first side surface and the second side surface are adjacent to each other, and the radius of curvature of the boundary portion between the first side surface and the second side surface in the lower part is more than half of the volume average particle diameter of the toner particles. A toner particle-carrying roller having a concave portion provided with a roundness on a surface thereof.
In this case, it is possible to realize a toner particle carrying roller in which toner particle retention is appropriately suppressed.

  The toner particle carrying roller has a flat bottom surface and a side surface adjacent to the bottom surface, and a radius of curvature at a boundary portion between the bottom surface and the side surface is more than half of a volume average particle diameter of the toner particles. The toner particle-carrying roller having a concave portion provided with a roundness on the surface has a non-recessed portion adjacent to the side surface on the opposite side of the bottom surface, and the curvature thereof at a boundary portion between the non-recessed portion and the side surface. A roundness having a radius that is half or more of the volume average particle diameter of the toner particles may be provided.

On the other hand, of the toner particle carrying roller, a concave portion having a planarly inclined portion and having a first side surface and a second side surface facing each other, the first side surface at the lower portion of the concave portion The second side surface is adjacent to each other, and a roundness having a radius of curvature of half or more of the volume average particle diameter of the toner particles is provided at a boundary portion between the first side surface and the second side surface in the lower part. In the toner particle carrying roller having a concave portion on the surface, the first side surface provided in the concave portion and the third side surface provided in another concave portion adjacent to the concave portion are the upper portion of the concave portion and the other concave portion. It is good also as the roundness which the curvature radius is more than half of the volume average particle diameter of a toner particle adjoining and the boundary part of this 1st side surface and this 3rd side surface is provided.
In such a case, the force acting on the toner particles is dispersed at the boundary portion between the side surface adjacent to the flat bottom surface and the non-recessed portion, or the boundary portion between the first side surface and the third side surface. It is possible to suppress the deformation of the particles.

The depth of the recess may be not more than twice the volume average particle size of the toner particles.
In such a case, it is possible to improve poor charging of the toner particles that occurs when the number of toner particles having a volume average particle size that overlaps in the depth direction of the concave portion exceeds two.

Further, the entire surface of the toner particle carrying roller may be a toner particle carrying unit for carrying toner particles.
In such a case, it is possible to suppress unevenness in the density of the toner image that occurs when developing the latent image carried on the photoreceptor.

A toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, the radius of curvature at the boundary between the bottom surface and the side surface being a volume average of the toner particles A concave portion provided with a roundness that is more than half of the particle diameter, and a non-recessed portion adjacent to the side surface on the opposite side of the bottom surface, and at a boundary portion between the non-recessed portion and the side surface, A roundness whose radius of curvature is at least half of the volume average particle diameter of the toner particles, and the depth of the recess is not more than twice the volume average particle diameter of the toner particles; A toner particle carrying roller characterized in that the whole is a toner particle carrying part for carrying toner particles, or a toner particle carrying roller for carrying toner particles, wherein a flat inclined portion is formed Have each other A concave portion having a first side surface and a second side surface facing each other, wherein the first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and the first side surface and the second side surface in the lower portion The first side surface provided with the concave portion, the concave portion having a radius of curvature that is a half of the volume average particle diameter of the toner particles, and the concave portion A third side surface included in another adjacent concave portion is adjacent to the concave portion and an upper portion of the other concave portion, and a radius of curvature is a volume of toner particles at a boundary portion between the first side surface and the third side surface. Roundness that is half or more of the average particle diameter is provided, the depth of the recess is not more than twice the volume average particle diameter of the toner particles, and the entire surface of the toner particle carrying roller carries toner particles. A toner particle carrying roller characterized by being a toner particle carrying part for It is.
In this way, the effects of the present invention can be achieved more effectively because all the effects described above can be achieved.

A toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, the radius of curvature at the boundary between the bottom surface and the side surface being a volume average of the toner particles A recess provided with a roundness that is half or more of the particle diameter, or a recess having a flat inclined portion and having a first side surface and a second side surface facing each other, The first side surface and the second side surface are adjacent to each other at the lower part, and the radius of curvature is more than half of the volume average particle diameter of the toner particles at the boundary between the first side surface and the second side surface in the lower part. It is also possible to realize a developing device including a toner particle carrying roller having a concave portion provided with a certain roundness on the surface.
In such a case, it is possible to realize a developing device including a toner particle carrying roller having a concave portion in which toner particle retention is appropriately suppressed.

  And a layer thickness regulating member for regulating the layer thickness of the toner particles carried on the surface of the toner particle carrying roller, and a flat surface of the layer thickness regulating member comes into contact with the toner particle carrying roller. The layer thickness may be regulated.

A toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, the radius of curvature at the boundary between the bottom surface and the side surface being a volume average of the toner particles A toner particle carrying roller having a concave portion provided with a roundness that is half or more of the particle diameter on the surface, or a toner particle carrying roller for carrying toner particles, and having a flat inclined portion. A concave portion having a first side surface and a second side surface facing each other, wherein the first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and the first side surface and the second side surface at the lower portion A developing device comprising a toner particle carrying roller having a concave portion provided on a surface thereof with a round portion having a radius of curvature of half or more of a volume average particle diameter of the toner particles at a boundary portion with the second side surface; Image shape characterized by having Device which can also be realized.
In such a case, it is possible to realize an image forming apparatus including a toner particle carrying roller having a concave portion in which toner particle retention is appropriately suppressed.

A computer and an image forming apparatus connectable to the computer, the toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, To carry a toner particle carrying roller having a concave portion provided on the surface thereof, or a concave portion provided with a roundness whose curvature radius is half or more of the volume average particle diameter of the toner particles at the boundary with the side surface, or for carrying toner particles A toner particle carrying roller having a planarly inclined portion and having a first side surface and a second side surface facing each other, wherein the first side surface and the A concave portion that is adjacent to the second side surface, and is provided with a roundness whose radius of curvature is more than half of the volume average particle diameter of the toner particles at the boundary between the first side surface and the second side surface in the lower part. , The surface has That the toner particles carrying roller image forming apparatus having a developing apparatus having a,, it can also be implemented image forming system characterized by comprising a.
In such a case, it is possible to realize an image forming system including a toner particle carrying roller having a concave portion in which toner particle retention is appropriately suppressed.

=== 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.

  As shown in FIG. 1, the printer 10 according to the present embodiment includes a charging unit 30, an exposure unit 40, a YMCK developing unit 50, a primary transfer unit 60, an intermediate transfer body 70, along the rotation direction of the photoreceptor 20. A cleaning unit 75, and further, a secondary transfer unit 80, a fixing unit 90, a display unit 95 configured as a liquid crystal panel that serves as a notification unit for a user, and a control unit that controls these units and the like and controls operations as a printer. 100.

  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 photoreceptor 20 into toner particles (hereinafter simply referred to as toner) accommodated in the developing device, that is, black (K) accommodated in the black developing device 51. To develop with toner, magenta (M) toner contained in the magenta developing device 52, cyan (C) toner contained in the cyan developing device 53, and yellow (Y) toner contained in the yellow developing device 54 It is a device.

  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, 54 described above is detachable from the holding portion of the YMCK developing unit 50. Details of each developing device will be described later.

The primary transfer unit 60 is a device for transferring a single color toner image formed on the photoconductor 20 to the intermediate transfer body 70. When four color toners are sequentially transferred in a superimposed manner, the full color toner is transferred to the intermediate transfer body 70. An image is formed.
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 and laminated on the surface layer. The intermediate transfer body 70 is rotationally driven 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 control unit 100 includes a main controller 101 and a unit controller 102. An image signal and a control signal are input to the main controller 101, and in response to a command based on the image signal and the control signal. A unit controller 102 controls each of the units and forms an image.

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 112 (shown as I / F in FIG. 2), a command from the main controller 101 is sent. The photosensitive member 20 and the intermediate transfer member 70 are rotated by the control of the unit controller 102 based on the above. 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 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 toner images of four colors corresponding to the respective image signals are transferred to the intermediate transfer body 70. Overlaid and transferred. 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. Further, 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 Control Unit ===
Next, the configuration of the control unit 100 will be described with reference to FIG. The main controller 101 of the control unit 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.

=== Configuration Example of Developing Device ===
Next, a configuration 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 the cross-sectional shape of the recess 516 provided on the surface of the developing roller 510, and shows a cross section along the direction indicated by the symbol X or the symbol Y in FIG. Here, 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. In FIG. 4, the vertical direction is indicated by arrows, and the central axis of the developing roller 510 as an example of the toner particle carrying roller is below the central axis of the photoconductor 20. In FIG. 4, the yellow developing device 54 is shown in a state where the yellow developing device 54 is located at the developing position facing the photoconductor 20. 5 to 7, the scales of the recesses 516 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 ) A yellow developing device 54 containing toner is provided, but since the configuration of each developing device is the same, the yellow developing device 54 will be described below.

The yellow developing device 54 includes a developing roller 510, an upper seal 520, a toner container 530, a housing 540, a toner supply roller 550, a regulating blade 560 as an example of a layer thickness regulating member, and the like.
The developing roller 510 is a member made of an aluminum alloy, an iron alloy, or the like, and carries the toner T on the surface thereof and transports the toner T to a developing position facing the photoreceptor 20.

As shown in FIGS. 6 and 7, the developing roller 510 is provided with a concave portion 516 and a non-recessed portion 519 in the central portion 510a of the surface thereof in order to appropriately carry the toner (note that the concave portion 516 and the non-recessed portion are not provided). Each of the concave portions 519 functions as a toner carrying portion for carrying toner. In the present embodiment, it is formed by subjecting the central portion 510a of the surface of the developing roller 510 to a so-called rolling process (the rolling process will be described in detail in the section of the developing device manufacturing method described later). The recessed portion 516 and the non-recessed portion 519 will be described.
The concave portion 516 is a portion that is recessed at the central portion 510a of the surface of the developing roller 510, and has a flat bottom surface 517 and a side surface 518 adjacent to the bottom surface.

  In the present embodiment, as shown in FIG. 7, the opening width and depth of the recess 516 are about 80 μm and about 7 μm, respectively. Further, the groove angle of the recess 516 (the angle represented by the symbol α in FIG. 7) is about 90 degrees. Further, at the boundary between the bottom surface 517 and the side surface 518, the radius of curvature R is a volume average particle diameter of the toner T (in the present embodiment, the toner T is in the form of particles) (in the present embodiment). Roundness which is more than half of 7 μm) is provided.

  The non-recessed portion 519 is a flat surface at the highest position in the central portion 510 a of the surface of the developing roller 510. As shown in FIG. 7, the non-recessed portion 519 is adjacent to the side surface 518 at a position opposite to the bottom surface 517 (opening side of the recessed portion 516). Further, a round portion whose radius of curvature R is not less than half of the volume average particle diameter of the toner T is also provided at a boundary portion between the non-recessed portion 519 and the side surface 518.

  In this embodiment, as shown in FIGS. 5 and 6, the concave portion 516 formed in the central portion 510 a of the surface of the developing roller 510 by the rolling process has two spiral grooves (hereinafter referred to as “winding grooves”) different in winding direction. , One of the spiral grooves is called a first groove 516a and the other is called a second groove 516b). That is, in FIG. 6, the recesses 516 arranged on the cross section in the X direction belong to the first groove 516a, and the recesses 516 arranged on the cross section in the Y direction belong to the second groove 516b. Here, the acute angles formed between the longitudinal direction of the first groove 516a and the second groove 516b and the axial direction of the developing roller 510 are about 45 degrees as shown in FIG. Further, the helical pitches of the first groove 516a and the second groove 516b (the length represented by the symbol L in FIG. 7) are both equally spaced.

  In the above embodiment, two spiral grooves having different winding directions are formed in the central portion 510a of the surface of the developing roller 510 as the recess 516. However, the present invention is not limited to this. It is not a thing. For example, only one of the first groove 516a and the second groove 516b may be provided.

  Further, as shown in FIG. 4, the developing roller 510 rotates in a direction (counterclockwise in FIG. 4) opposite to the rotation direction of the photoconductor 20 (clockwise in FIG. 4). The central axis is below the central axis of the photoconductor 20.

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

  The housing 540 is manufactured by welding a plurality of integrally formed resin housing parts, that is, the upper housing part 542 and the lower housing part 544, and in order to accommodate the toner T therein. The toner container 530 is formed. The toner containing body 530 has two toner containing portions, that is, a first toner containing portion 530a and a second toner, by a partition wall 545 for 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. The upper portions of the first toner storage portion 530a and the second toner storage portion 530b communicate with each other, and the movement of the toner T is restricted by the partition wall 545 in the state shown in FIG. However, when the YMCK developing unit 50 rotates, the toner T accommodated in the first toner accommodating portion 530a and the second toner accommodating portion 530b is temporarily moved to the communication portion side on the upper side in the developing position. When the toner T is collected and returns to the state shown in FIG. 4, the toners T are mixed and returned to the first toner storage portion 530a and the second toner storage portion 530b. That is, when the YMCK developing unit 50 rotates, the toner in the developing device is appropriately agitated.

  For this reason, in this embodiment, the toner container 530 is not provided with a stirring member, but a stirring member for stirring the toner T stored in the toner container 530 may be provided. 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. 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 inside the housing 540 is restricted. The upper seal 520 is a seal made of a polyethylene film or the like. The upper seal 520 is supported by an upper seal support portion 526, and is provided so that its longitudinal direction is along the axial direction of the developing roller 510. The contact position where the upper seal 520 contacts the developing roller 510 is above the central axis of the developing roller 510.

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

The regulating blade 560 contacts the developing roller 510 at the contact portion 562a from one end to the other end in the axial direction of the developing roller 510. Further, the layer thickness of the toner T carried on the developing roller 510 is regulated, and an electric charge is applied to the toner T carried on the developing roller 510. As shown in FIG. 4, the regulation blade 560 includes a rubber part 562 and a rubber support part 564.
The rubber part 562 is made of silicon rubber, urethane rubber, or the like, and is in contact with the developing roller 510.

  The rubber support portion 564 includes a thin plate 564a and a thin plate support portion 564b, and supports the rubber portion 562 at one end portion 564c 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 564d in the short side direction of the rubber support portion 564, and the thin plate support portion 564b is a side of the thin plate 564a that supports the rubber portion 562. It is attached to the said thin plate 564a in the state which supported the edge on the opposite side.

  The end of the regulating blade 560 opposite to the thin plate support portion 564b side, that is, the tip 560a is not in contact with the developing roller 510, and is a portion separated from the tip 560a by a predetermined distance (that is, the contact portion 562a). ) Is in contact with the developing roller 510 with a width. That is, the regulating blade 560 is not in contact with the developing roller 510 at the edge thereof, and the layer thickness is regulated by contacting the developing roller 510 with a plane provided on the regulating blade 560.

  Further, the regulating blade 560 is disposed so that its tip 560a faces the upstream side in the rotation direction of the developing roller 510, and is in contact with a so-called counter. The contact position where the regulating blade 560 contacts the developing roller 510 is below the central axis of the developing roller 510 and below the central axis of the toner supply roller 550. Further, the regulation blade 560 exhibits a function of preventing leakage of the toner T from the toner container 530 by contacting the developing roller 510 along the axial direction thereof. A housing seal 546 for preventing the toner T from leaking is provided between the regulating blade 560 and the housing 540.

  In the yellow developing device 54 configured as described above, the toner supply roller 550 supplies the toner T stored in the toner container 530 to the developing roller 510. The toner T supplied to the developing roller 510 reaches the contact position of the regulating blade 560 as the developing roller 510 rotates, and the layer thickness is regulated and electric charge is applied when passing through the contact position. Is done. The toner T on the developing roller 510 to which the layer thickness is regulated and the electric charge is applied reaches the developing position facing the photosensitive member 20 by further rotation of the developing roller 510, and the photosensitive member is subjected to an alternating electric field at the developing position. The latent image formed on 20 is subjected to development. The toner T on the developing roller 510 that has passed the developing position by further rotation of the developing roller 510 passes through the upper seal 520 and is collected in the developing device without being scraped off by the upper seal 520. Further, the toner T still remaining on the developing roller 510 can be peeled off by the toner supply roller 550.

=== Effectiveness of Developing Device According to this Embodiment ===
As described above, the developing roller 510 according to the present embodiment includes the flat bottom surface 517 and the side surface 518 adjacent to the bottom surface, and the curvature radius R is the volume average of the toner at the boundary between the bottom surface and the side surface. The surface has a recess 516 provided with a roundness that is half or more of the particle diameter. As a result, it is possible to realize a developing roller in which toner retention is appropriately suppressed.
That is, as described in the background section, the surface of the developing roller 510 is provided with a flat bottom surface 517 and a concave portion 516 having a side surface 518 adjacent to the bottom surface in order to properly carry the toner. Yes.

However, conventionally, a corner is provided at the boundary portion between the bottom surface 517 and the side surface 518, and there has been a problem that toner, in particular, fine powder toner stays in the boundary portion. Here, the problem will be described with reference to FIG. FIG. 8 is an explanatory diagram for explaining a problem that has occurred in the recess 516 of the developing roller 510 according to the conventional example.
As shown in FIG. 8, in the case where the boundary between the flat bottom surface 517 provided in the recess 516 and the side surface 518 adjacent to the bottom surface has a corner, the toner, particularly the fine powder toner, is formed at the corner. Since the toner does not come into contact with a toner having a relatively large volume particle diameter (hereinafter referred to as a large particle diameter toner) that rolls in the interior, the toner is not discharged by the large particle diameter toner but stays in the recess 516.

In contrast, the recess 516 included in the developing roller 510 according to the present embodiment solves the above problem. This will be described with reference to FIG. FIG. 9 is an explanatory diagram for explaining the effectiveness of the recess 516 included in the developing roller 510 according to the present embodiment.
As shown in FIG. 9, the concave portion 516 is provided with a roundness whose curvature radius R is half or more of the volume average particle diameter of the toner at the boundary between the bottom surface 517 and the side surface 518. With the concave portion 516 having such a structure, most of the large particle size toner rolls in contact with the boundary portion, so that a toner smaller than the large particle size toner can be appropriately discharged out of the concave portion 516. Therefore, toner retention can be appropriately suppressed.

In the present embodiment, as shown in FIG. 7, the curvature is present at the boundary portion between the side surface 518 adjacent to the flat bottom surface 517 provided in the recess 516 and the non-recess 519 adjacent to the side surface. Although the roundness having the radius R of half or more of the volume average particle diameter of the toner is provided, the present invention is not limited to this. For example, in FIG. 7, the boundary between the non-recessed portion 519 and the side surface 518 may have a corner. However, in such a case, stress concentrates on the local portion of the toner from the corner, and the stress may cause deformation of the toner.
On the other hand, in the case where the boundary portion between the side surface 518 and the non-recessed portion 519 is provided with a roundness whose curvature radius R is half or more of the volume average particle diameter of the toner, the toner is formed in the boundary portion. The force acting on the toner is dispersed, and the deformation of the toner can be suppressed. In this respect, the present embodiment is more desirable.

=== About other concave shapes ===
In the above, a flat bottom surface 517 and a side surface 518 adjacent to the bottom surface are provided as concave portions for appropriately suppressing toner retention, and the radius of curvature R is the volume average of the toner at the boundary between the bottom surface and the side surface. The concave part (example in this case) provided with a roundness larger than half of the particle diameter was described. However, this example is an example of a recess that appropriately suppresses toner retention, and other examples are also conceivable. In this section, a concave portion (modified example) having a shape different from the present example will be described. FIG. 10 corresponds to FIG. 6 and is a schematic front view of the developing roller 510 according to the modification. FIG. 11 is a schematic diagram showing a cross-sectional shape of the recess 580 according to the modification, and shows a cross section along the direction indicated by the symbol X or the symbol Y in FIG. 10 and 11, the scales of the recesses 580 and the like are different from the actual ones.

  The concave portion 580 according to the present modified example has first flat side surfaces that have flatly inclined portions (hereinafter referred to as flat inclined portions) 581a and 582a in the central portion 510a of the surface of the developing roller 510 and face each other. 581 and a second side surface 582.

  In the present modification, there is no equivalent of the non-recessed portion 519 in the central portion 510 a of the surface of the developing roller 510. As shown in FIG. 11, the recess 580 is adjacent to another recess 583 adjacent to the recess 580. That is, the first side surface 581 and the third side surface 584 are adjacent to each other at the upper part (opening side) of the recess 580 and the other recess 583. The other concave portion 583 includes a third side surface 584 and a fourth side surface 585 facing each other. Like the concave portion 580, the third side surface 584 and the fourth side surface 585 are each a flat inclined portion 584a. 585a.

  In this modification, as shown in FIG. 11, the opening width and depth of the recess 580 are about 80 μm and about 7 μm, respectively. Further, the groove angle of the recess 580 (the angle represented by the symbol α in FIG. 11) is about 110 degrees. Further, a round portion having a radius of curvature R that is not less than half of the volume average particle diameter of the toner particles is provided at the boundary between the first side surface 581 and the second side surface 582.

  Further, the boundary portion between the first side surface 581 and the third side surface 584 is provided with a roundness whose curvature radius R is half or more of the volume average particle diameter of the toner. However, the present invention is not limited to this. is not. For example, in FIG. 11, the boundary between the first side surface 581 and the third side surface 584 may have a corner. However, from the viewpoint of suppressing the deformation of the toner, the form of this modification is more desirable.

  In this modified example, as shown in FIGS. 10 and 11, the concave portion 580 formed in the central portion 510a on the surface of the developing roller 510 has a first groove 580a having a different winding direction as in the present example. And a second groove 580b is formed. That is, in FIG. 10, the recesses 580 aligned on the X-direction cross section belong to the first groove 580a, and the recesses 580 aligned on the Y-direction cross section belong to the second groove 580b.

  Here, the acute angles formed by the longitudinal direction of the first groove 580a and the second groove 580b and the axial direction of the developing roller 510 are about 45 degrees as shown in FIG. In addition, the spiral pitches (the length represented by the symbol L in FIG. 11) of the first groove 580a and the second groove 580b are both equally spaced.

=== Method for Manufacturing Developing Roller ===
Next, a method for manufacturing the developing roller 510 described above will be described with reference to FIGS. 12A to 13. 12A to 12E are schematic diagrams showing the transition of the developing roller 510 in the manufacturing process of the developing roller 510. FIG. FIG. 13 is an explanatory diagram for explaining the rolling process of the developing roller 510. In the following description, among the black developing device 51, the magenta developing device 52, the cyan developing device 53, and the yellow developing device 54, the yellow developing device 54 will be described as an example.

First, as shown in FIG. 12A, 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. 12B, flange press-fit portions 602 are formed at both longitudinal ends of the pipe material 600. The flange press-fit portion 602 is made by cutting.
Next, as shown in FIG. 12C, 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. 12D, the flange 604 performs centerless polishing on the surface of the press-fitted pipe material 600. 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. 12E, the flange 604 is formed into a concave portion 516 (in the modified example) by rolling to a portion corresponding to the central portion 510a of the surface of the developing roller 510 in the surface of the pipe material 600 that is press-fitted. Forms a recess 580). 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. 13, 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. 13) in a state of being pressed with a symbol P). Convex portions 650a and 652a for forming the concave portion 516 or the concave portion 580 are provided on the surfaces of the round dies 650 and 652, and the pipe material 600 is deformed by the convex portions 650a and 652a. A recess 516 or a recess 580 is formed in 600. In the through-feed rolling, the round dies 650 and 652 rotate, so that the pipe material 600 rotates in the direction opposite to the rotation direction of the round dies 650 and 652 (see FIG. 13). Move in the direction indicated by H. In the portion corresponding to the central portion 510a of the surface of the developing roller 510, the first groove 516a (in the modified example, the first groove 580a) is formed by the convex portion 650a of the round die 650, and the second groove 516b (in the modified example). The second grooves 580b) are respectively formed by the convex portions 652a of the round dies 652.

  In addition, in order to realize the developing roller 510 according to the present example and the modified example, as round dies 650 and 652 used when the through-feed rolling process is performed, on the edge portions of the convex portions 650a and 652a, A die having a radius of curvature larger than half of the volume average particle diameter of the toner (for example, a round chamfering die) may be used.

  Then, after the rolling process is finished, the central portion 510a of the surface of the developing roller 510 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 ===
As described above, the developing roller 510 according to the present invention has been described based on the above-described embodiment. However, the above-described embodiment is for facilitating understanding of the present invention and is intended to limit 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.

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

In the above embodiment, the depth of the concave portion 516 (in the modified example, the concave portion 580) is not more than twice the value 7 μm of the volume average particle diameter of the toner (that is, 14 μm). It is not limited. For example, the depth of the recess 516 in FIG. 7 (in the modified example, the recess 580 in FIG. 12) may be greater than twice the volume average particle diameter of the toner.
However, in the above embodiment, the charging failure of the toner is improved in the case where the number of the toner having the volume average particle size overlapped in the depth direction of the concave portion 516 or the concave portion 580 is more than two. Is preferred. That is, most of the toner positioned between the developing roller 510 and the regulating blade 560 in the concave portion 516 or the concave portion 580 rolls in contact with at least one of the surface of the developing roller 510 and the regulating blade 560. Therefore, the chargeability of the toner becomes appropriate.

In the above embodiment, the entire surface of the developing roller 510 (in the above embodiment, the central portion 510a of the surface of the developing roller 510) is a toner carrying portion for carrying toner. It is not limited to this. For example, in FIG. 7, the toner may be carried only in the recess 516.
However, the above embodiment is preferable in that it is possible to suppress the occurrence of density spots in the toner image when developing the latent image carried on the photosensitive member.

  In the above-described embodiment, the regulating blade 560 for regulating the layer thickness of the toner carried on the surface of the developing roller 510 is brought into contact with the developing roller 510 on the plane of the regulating blade, whereby the layer thickness is increased. However, the present invention is not limited to this. For example, the regulation blade 560 may regulate the layer thickness by contacting the developing roller 510 with an edge of the regulation blade 560.

=== 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. 14 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, but 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. 15 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. . 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 each function or mechanism of the computer 702, the display device 704, the input device 708, and the reading device 710. As an example, the printer 706 includes an image processing unit that performs image processing, a display unit that performs various displays, and 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.

  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 control unit 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. 5 is a schematic diagram showing a cross-sectional shape of a recess 516. FIG. It is explanatory drawing for demonstrating the problem which has generate | occur | produced in the recessed part 516 which the developing roller 510 which concerns on a prior art example has. It is a figure for demonstrating the effectiveness of the recessed part 516 which the developing roller 510 which concerns on this Embodiment has. It is a front schematic diagram of the developing roller 510 according to a modification. FIG. 10 is a schematic diagram illustrating a cross-sectional shape of a recess 580 included in a developing roller 510 according to a modification. 12A to 12E are schematic diagrams showing the transition of the developing roller 510 in the manufacturing process of the developing roller 510. FIG. 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. It is a block diagram which shows the structure of the image forming system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser beam printer 20 Photoconductor 30 Charging unit 40 Exposure unit 50 YMCK developing unit 50a Center shaft 51 Black developing device 52 Magenta developing device 53 Cyan developing device 54 Yellow developing devices 55a and 55b Holding unit 55c and 55d Holding unit 60 Primary transfer unit 70 Intermediate transfer body 75 Cleaning unit 76 Cleaning blade 80 Secondary transfer unit 90 Fixing unit 92 Paper feed tray 94 Paper feed roller 95 Display unit 96 Registration roller 100 Control unit 101 Main controller 102 Unit controller 112 Interface 113 Image memory 510 Developing roller 510a Center Portion 516 Recess 516a First groove 516b Second groove 517 Bottom surface 518 Side surface 519 Non-recess 520 Upper seal 520b Contact surface 520c Opposite surface 524 Upper seal biasing member 526 Upper seal support portion 530 Toner container 530a First toner storage portion 530b Second toner storage portion 540 Housing 542 Upper housing portion 544 Lower housing portion 545 Partition wall 546 Housing seal 550 Toner supply roller 560 Restriction blade 560a Tip 562 Rubber portion 562a Abutting portion 564 Rubber support portion 564a Thin plate 564b Thin plate support portion 564c Short-side end portion 564d Short-side end portion 572 Opening 580 Recessed portion (Modification)
580a First groove 580b Second groove 581 First side surface 581a Planar inclined portion 582 Second side surface 582a Planar inclined portion 584 Third side surface 584a Planar inclined 585 Fourth side surface 585a Planar inclined 583 Other concave portion 600 Pipe material 602 Flange press-fit portion 604 Flange 650 Round die 650a Convex portion 652 Round die 652a Convex portion 700 Image forming system 702 Computer 704 Display device 706 Printer 708 Input device 708A Keyboard 708B Mouse 710 Reading device 710A Flexible disk drive device 710B CD-ROM drive device 802 Internal memory 804 Hard disk drive unit T Toner particles

Claims (15)

A toner particle carrying roller for carrying toner particles,
A recess provided with a flat bottom surface and a side surface adjacent to the bottom surface, and provided with a roundness whose radius of curvature is more than half of the volume average particle diameter of toner particles at the boundary between the bottom surface and the side surface;
On the surface of the toner particle carrying roller. The toner particle carrying roller according to claim 1,
A non-recessed portion adjacent to the side surface on the side opposite to the bottom surface, and a rounded portion having a radius of curvature of half or more of a volume average particle diameter of the toner particles at a boundary portion between the non-recessed portion and the side surface;
And a toner particle carrying roller. A toner particle carrying roller for carrying toner particles,
A first side surface and a second side surface facing each other, each having a flatly inclined portion;
The first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and a radius of curvature is formed at a boundary portion between the first side surface and the second side surface in the lower portion. A recess provided with a roundness that is more than half of the volume average particle diameter of the toner particles,
On the surface of the toner particle carrying roller. The toner particle carrying roller according to claim 3,
The first side surface provided in the concave portion and the third side surface provided in another concave portion adjacent to the concave portion,
A roundness adjacent to the upper portion of the concave portion and the other concave portion, and having a radius of curvature of half or more of a volume average particle diameter of toner particles at a boundary portion between the first side surface and the third side surface;
And a toner particle carrying roller. In the toner particle carrying roller according to any one of claims 1 to 4,
A toner particle carrying roller, wherein the depth of the recess is not more than twice the volume average particle diameter of the toner particles. A toner particle carrying roller according to any one of claims 1 to 5,
A toner particle carrying roller, wherein the entire surface of the toner particle carrying roller is a toner particle carrying part for carrying toner particles. A toner particle carrying roller for carrying toner particles,
A recess provided with a flat bottom surface and a side surface adjacent to the bottom surface, and provided with a roundness whose radius of curvature is more than half of the volume average particle diameter of toner particles at the boundary between the bottom surface and the side surface;
On the surface,
A non-recessed portion adjacent to the side surface on the side opposite to the bottom surface, and a rounded portion having a radius of curvature of half or more of a volume average particle diameter of the toner particles at a boundary portion between the non-recessed portion and the side surface;
Is provided,
The depth of the recess is not more than twice the volume average particle diameter of the toner particles;
A toner particle carrying roller, wherein the entire surface of the toner particle carrying roller is a toner particle carrying part for carrying toner particles. A toner particle carrying roller for carrying toner particles,
A first side surface and a second side surface facing each other, each having a flatly inclined portion;
The first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and a radius of curvature is formed at a boundary portion between the first side surface and the second side surface in the lower portion. A recess provided with a roundness that is more than half of the volume average particle diameter of the toner particles,
On the surface,
The first side surface provided in the concave portion and the third side surface provided in another concave portion adjacent to the concave portion,
A roundness adjacent to the upper portion of the concave portion and the other concave portion, and having a radius of curvature of half or more of a volume average particle diameter of toner particles at a boundary portion between the first side surface and the third side surface;
Is provided,
The depth of the recess is not more than twice the volume average particle diameter of the toner particles;
A toner particle carrying roller, wherein the entire surface of the toner particle carrying roller is a toner particle carrying part for carrying toner particles. A toner particle carrying roller for carrying toner particles,
A recess provided with a flat bottom surface and a side surface adjacent to the bottom surface, and provided with a roundness whose radius of curvature is more than half of the volume average particle diameter of toner particles at the boundary between the bottom surface and the side surface;
A toner particle carrying roller having a surface thereof,
A developing device comprising: A toner particle carrying roller for carrying toner particles,
A first side surface and a second side surface facing each other, each having a flatly inclined portion;
The first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and a radius of curvature is formed at a boundary portion between the first side surface and the second side surface in the lower portion. A recess provided with a roundness that is more than half of the volume average particle diameter of the toner particles,
A toner particle carrying roller having a surface thereof,
A developing device comprising: In the developing device according to claim 9 or 10,
A layer thickness regulating member for regulating the layer thickness of the toner particles carried on the surface of the toner particle carrying roller;
The developing device according to claim 1, wherein the layer thickness is regulated by contacting a flat surface of the layer thickness regulating member with the toner particle carrying roller. A toner particle carrying roller for carrying toner particles,
A recess provided with a flat bottom surface and a side surface adjacent to the bottom surface, and provided with a roundness whose radius of curvature is more than half of the volume average particle diameter of toner particles at the boundary between the bottom surface and the side surface;
A toner particle carrying roller having a surface thereof,
An image forming apparatus comprising: a developing device comprising: A toner particle carrying roller for carrying toner particles,
A first side surface and a second side surface facing each other, each having a flatly inclined portion;
The first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and a radius of curvature is formed at a boundary portion between the first side surface and the second side surface in the lower portion. A recess provided with a roundness that is more than half of the volume average particle diameter of the toner particles,
A toner particle carrying roller having a surface thereof,
An image forming apparatus comprising: a developing device comprising: Computer and
An image forming apparatus connectable to the computer, comprising a toner particle carrying roller for carrying toner particles, comprising a flat bottom surface and a side surface adjacent to the bottom surface, and a boundary portion between the bottom surface and the side surface An image forming apparatus having a developing device provided with a toner particle carrying roller having a concave portion provided with a round surface, the curvature radius of which is half or more than the volume average particle diameter of the toner particles.
An image forming system comprising: Computer and
An image forming apparatus connectable to the computer, a toner particle carrying roller for carrying toner particles, having a flatly inclined portion, and a first side surface and a second side surface facing each other,
The first side surface and the second side surface are adjacent to each other at a lower portion of the concave portion, and a radius of curvature is formed at a boundary portion between the first side surface and the second side surface in the lower portion. An image forming apparatus having a developing device provided with a toner particle carrying roller having a concave portion provided with a roundness which is half or more of a volume average particle diameter of toner particles on the surface;
An image forming system comprising: