CN101482722A - Developing device, toner particle carrying roller, image forming apparatus, image forming system, and method of manufacturing toner particle carrying roller - Google Patents

Abstract

The invention provides a developing device and an image forming device. The developing device has: an accommodating portion accommodating toner particles for developing a latent image carried on the image carrier; Helical grooves inclined in the axial direction and circumferential direction and formed at equal intervals in the axial direction.

Description

Developing device and image forming device

This application is a divisional application based on the invention patent application filed on October 31, 2006 with the application number 200610150467.X and the title of the invention "developing device and image forming device".

technical field

The present invention relates to a developing device and an image forming device.

Background technique

A developing device that performs development using toner particles is known as a developing device having a toner particle carrying roller for carrying toner particles accommodated in a toner particle container and performing development. .

In order to limit the layer thickness of the toner particles carried by the toner particle carrying roller and to charge the toner particles, such a developing device is provided with a layer thickness that is in contact with the toner particle carrying roller that carries the toner particles. Limit parts. In addition, the surface of the toner particle carrying roller is subjected to sand blasting so that fine irregularities are provided on the surface. The toner particles are carried on the surface of the toner particle carrying roller and pressed by the layer thickness regulating member, whereby the toner particles roll while being rubbed by the uneven surface, the layer thickness regulating member, etc., thereby being charged.

In this developing device, when the unevenness of the surface of the toner particle carrying roller is formed by sandblasting, the size, depth, shape, and arrangement method of the concave portions are not uniform. Therefore, for example, toner particles entering deep recesses cannot be well charged because they are not rolled. In this way, due to uneven unevenness of the unevenness on the surface of the toner particle carrying roller, charging failure of toner particles may occur locally, or toner particles may enter small recesses to cause filming. In addition, if the toner particles are not well charged, there is a problem that the toner particles leak from the developing device and disperse into the image forming device, or generate fog on the image, or the like.

Japanese patent documents JP-A-2003-263018, JP-A-1-102486, and JP-A-2005-84533 are all examples of related technologies.

Contents of the invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing device having a toner particle carrying roller capable of satisfactorily charging toner particles.

The main invention is the following developing device.

The developing unit has:

an accommodating portion accommodating toner particles for developing a latent image carried on the image carrier; and a toner particle carrying roller having, on a surface for carrying the toner particles, a Helical grooves inclined in the circumferential direction and formed at equal intervals in the axial direction.

Other features of the present invention will be further clarified by the accompanying drawings and the following description.

Description of drawings

For a more thorough understanding of the present invention and its advantages, please refer to the following description and accompanying drawings.

Fig. 1 is a schematic diagram of the main components constituting the printer;

FIG. 2 is a diagram for explaining the configuration of a control unit included in the printer;

Figure 3 is a perspective view of a yellow developer;

4 is a cross-sectional view showing the main constituent parts of a yellow developer;

Fig. 5 is a perspective view showing a developing device with a developing roller removed;

Fig. 6 is a schematic view for explaining the surface shape of the developing roller;

Fig. 7 is a cross-sectional view for explaining the cross-section of the developing roller cut with a plane passing through the shaft;

FIG. 8 is a diagram for explaining a situation in which a developing roller is formed by roll forming;

FIG. 9 is a diagram showing a process of forming a developing roller;

FIG. 10 is a diagram for explaining a state where the regulating blade abuts against the developing roller carrying the toner particles;

FIG. 11 is a diagram for explaining resolutions in screens and latent images;

12 is a schematic diagram of a first modification of the developing roller;

Fig. 13 is a schematic diagram of a second modified example of the developing roller;

14 is a schematic diagram of a third modified example of the developing roller;

15 is a schematic perspective view of a developing roller of a developing device according to a second embodiment;

16 is a schematic front view of a developing roller of a developing device according to a second embodiment;

Fig. 17 is a schematic cross-sectional shape diagram of a groove related to the second embodiment;

Fig. 18 is a schematic cross-sectional view of A-A of Fig. 16;

19 is a schematic perspective view of a developing roller of a developing device according to a third embodiment;

20 is a schematic front view of a developing roller of a developing device according to a third embodiment;

Fig. 21 is a schematic diagram of the cross-sectional shape of the trench according to the third embodiment;

Figure 22 is a schematic cross-sectional view of A-A of Figure 20;

23 is a schematic front view of a developing roller according to a first modified example of the third embodiment;

FIG. 24 is an explanatory diagram for explaining the effectiveness of the first modified example of the third embodiment;

25 is a schematic front view of a developing roller according to a second modified example of the third embodiment;

26 is an enlarged view of the vicinity of the end of the groove forming portion according to the fourth embodiment;

27 is a diagram showing a state where pile yarns are in contact with groove forming portions of the developing roller according to the fourth embodiment;

FIG. 28 is an explanatory diagram showing the external configuration of the image forming system;

FIG. 29 is a block diagram showing the configuration of the image forming system shown in FIG. 28 .

Detailed ways

At least the following matters can be clarified from the description of this specification and the drawings.

The developing unit has:

an accommodating portion accommodating toner particles for developing a latent image carried on the image carrier; and

The toner particle carrying roller has, on a surface for carrying the toner particles, helical grooves inclined with respect to the axial direction and the circumferential direction and formed at equal intervals in the axial direction.

The toner particle carrying roller carries toner particles on its surface to develop the latent image on the image carrying roller. At this time, if irregularities in depth, shape, etc. are formed on the surface of the toner particle carrying roller, for example, the toner particles that have entered deep recesses among the carried toner particles will be difficult to roll, Thus it is difficult to electrify. In addition, when the circumferential grooves are formed at predetermined intervals in the axial direction, since the position of the portion of the image carrier facing the grooves does not change in the axial direction, the developed toner image The density may become higher at the portion opposite to the groove portion. On the other hand, when grooves along the axial direction are formed at predetermined intervals in the circumferential direction, since the rotation direction of the toner particle carrying roller is almost perpendicular to the direction of the grooves, the carried toner The rolling of the particles is very difficult, making it difficult to charge.

If it is a developing device that has spiral grooves formed at equal intervals in the axial direction and inclined with respect to the axial direction and the circumferential direction on the surface of the toner carrying roller as described above, it is possible to make the toner particles The toner particles are well charged by rolling and moving simultaneously with the rotation of the toner particle carrying roller. In addition, since the position of the image carrier relative to the groove portion changes sequentially in the axial direction and the circumferential direction as the toner carrying roller rotates, it is possible to suppress density unevenness of the developed toner image.

In addition, the depth of the groove portion may be twice or less than the volume average particle diameter of the toner particles.

According to such a developing device, since the depth of the groove portion is not more than twice the volume average particle diameter of the toner particles, the toner particles entering the groove portion do not overlap twice in the depth direction in the groove portion. more than one. Therefore, the toner particles in the groove portion can be rolled uniformly, so that they can be well charged.

In addition, the latent image has a dot-like latent image formed in a region divided into a grid, and the grid can be formed at various pitches in the axial direction, and the groove portion can be formed in the axial direction. The pitch is smaller than the longest pitch among the various pitches of the grid.

According to such a developing device, the dots on which the respective dot-shaped latent images are developed are formed on the portion of the toner particle carrying roller including the groove portion. Therefore, it is possible to suppress density unevenness of the developed toner image due to the groove portion.

In addition, the developing device may also be constituted as follows:

The toner particle carrying roller includes: a central portion including the groove portion provided concavely by a processing tool and a convex portion having a surface not in contact with the processing tool; and both ends not to be processed. portion; the developing device further has a layer thickness regulating member that carries the toner particles over the entire area from the central portion to the both end portions of the toner particle carrying roller. The roller abuts to limit the layer thickness of the toner particles carried on the toner particle carrying roller.

According to such a developing device, the top surface of the convex portion and the peripheral surfaces of both end portions are positioned on the peripheral surface of the toner particle carrying roller having the same radius from the axial center. Therefore, even if the layer thickness regulating member for restricting the layer thickness of the toner particles abuts against the toner particle carrying roller over the entire region from the center to both ends of the toner particle carrying roller, the layer thickness regulating member There is no large bending in the axial direction, and they abut in a nearly flat state. That is, since the layer thickness regulating member does not bend greatly, it is possible to prevent a gap from being generated between the toner particle carrying roller and the layer thickness regulating member. In addition, by pressing the toner particles carried on the toner particle carrying roller substantially uniformly by the layer thickness regulating member, the toner particles can be well charged.

In addition, two kinds of the groove portions having different inclination angles with respect to the axial direction and the circumferential direction may be formed.

According to such a developing device, since two kinds of groove portions having different inclination angles are formed on the toner particle carrying roller, the toner particles move in two directions along the groove portions. Therefore, it is possible to prevent the toner particles from being displaced by moving only in one predetermined direction.

In addition, the distance from the top surface of the convex portion to the bottom surface of the groove portion may be constant.

According to such a developing device, since the distance from the top surface of the convex portion to the bottom surface of the groove portion is constant, the amount of toner particles entering into the groove portion is approximately uniform throughout the entire area of the groove portion. Therefore, the amount of toner particles carried on the toner particle carrying roller can be made substantially uniform over the entire area of the toner particle carrying roller.

In addition, the distance from the top surface of the convex portion to the bottom surface of the groove portion may be equal to or less than twice the volume average particle diameter of the toner particles.

According to such a developing device, since the depth of the groove portion is not more than twice the volume average particle diameter of the toner particles, the toner particles entering the groove portion do not overlap in the depth direction in the groove portion. more than two. Therefore, it is possible to roll the toner particles in the groove portion without causing unevenness, and to charge them well.

In addition, the developing device may also be constituted as follows:

The toner particle carrying roller includes: a concave-convex processed part located at the central part in the axial direction of the toner particle carrying roller, the surface of which is concave-convex processed for carrying toner particles; a non-concave-convex processed part, In the axial direction of the toner particle carrying roller, it is located at both ends, and the surface is not subjected to uneven processing; in the middle part, in the axial direction of the toner particle carrying roller, it is located between the uneven processing part and the between the non-concave-convex processed parts, and has a radius smaller than the maximum radius of the concave-convex processed part and larger than the radius of the non-concave-convex processed part; A member abuts against the toner particle carrying roller over the entire area from one end portion to the other end portion in the axial direction of the toner particle carrying roller, for restricting the toner particle carrying roller The thickness of the layer on the toner particles.

In this case, a developing device in which the layer thickness of the toner particles carried on the toner particle carrying roller is appropriately limited can be realized.

In addition, the radius of the middle portion may be larger on the side of the uneven portion of the middle portion, and may be smaller on the side of the non-roughened portion of the middle portion.

In this case, a developing device in which the layer thickness of the toner particles carried on the toner particle carrying roller is appropriately limited can be realized.

In addition, the radius of the middle portion may gradually decrease from the side of the uneven portion to the side of the non-rough portion of the middle portion.

In this case, a developing device in which the layer thickness of the toner particles carried on the toner particle carrying roller is further appropriately restricted can be realized.

In addition, a sealing member for preventing leakage of toner particles may be provided along the peripheral surface of the toner particle carrying roller in contact with the non-concave-convex processed part, and the surface of the concavo-convex processed part may be coating treatment, and no coating treatment is performed on the surface of the middle part.

In this case, the chargeability of the toner particles can be improved and leakage of the toner particles can be properly prevented.

In addition, the developing device may also be constituted as follows:

The toner particle carrying roller includes: a groove forming portion on the surface of which the groove portion is formed, and at an axial end portion of the toner particle carrying roller of the groove forming portion. The depth of the formed groove portion is smaller than the depth of the groove portion formed at the central portion of the groove forming portion in the axial direction; The groove portion is not formed on the outer side of the portion; the developing device further includes a sealing member that is in contact with the non-groove forming portion along the peripheral surface of the toner particle carrying roller, Used to prevent leakage of toner particles.

In this case, a developing device in which leakage of toner particles is properly prevented can be realized.

In addition, the developing device may also be constituted as follows:

The toner particle carrying roller includes: a groove forming portion on the surface of which the groove portion is formed, and at an axial end portion of the toner particle carrying roller of the groove forming portion. The acute angle formed between the longitudinal direction of the formed groove portion and the axial direction is larger than the acute angle formed between the longitudinal direction of the groove portion formed at the central portion of the groove forming portion in the axial direction and the axial direction. The acute angle of the non-groove forming portion is located outside the groove forming portion in the axial direction, and the groove portion is not formed; the developing device further has a sealing member along the The non-groove forming portion is in contact with the toner particles carrying the peripheral surface of the roller to prevent leakage of the toner particles.

In this case, a developing device in which leakage of toner particles is properly prevented can be realized.

In addition, the developing device may be configured as follows: the toner particle carrying roller rotates in a predetermined rotation direction, and includes a groove forming portion on the surface of which the groove portion is formed, and the groove forming portion The central portion in the axial direction of the toner particle carrying roller is formed with a first groove portion and a second groove portion having different winding directions as the groove portion, and in the groove forming portion Only one of the first groove portion and the second groove portion is formed at the end portion in the axial direction; the non-groove forming portion is located in the groove in the axial direction The groove portion is not formed on the outer side of the forming portion; the developing device further includes a sealing member that is in contact with the non-groove forming portion along the peripheral surface of the toner particle carrying roller. , for preventing the leakage of toner particles; when in two directions facing opposite directions to each other along the length direction of the groove portion formed on the end portion, the directions are aligned along the toner particles When the circumferential direction of the carrying roller coincides with the rotation direction as the first direction, the first direction along the axial direction of the toner particle carrying roller is the same as the direction from the end toward the The direction of the central portion coincides with the latter of the directions from the end portion toward the non-groove forming portion.

In this case, a developing device in which leakage of toner particles is properly prevented can be realized.

In addition, the surface of the central portion may be plated, and the surface of the end portion may not be plated.

In this case, the chargeability of the toner particles can be improved, and leakage of the toner particles can be properly prevented.

In addition, the developing device can also be constituted as follows:

The toner particle carrying roller includes a groove forming portion on a surface of which the groove portion is formed, and the developing device further includes a sealing member along which the toner The peripheral surface of the particle carrying roller is in contact with the groove forming portion to prevent leakage of toner particles, and the surface of the sealing member in contact with the groove forming portion is made of fabric.

In this case, leakage of toner particles can be properly prevented.

In addition, the developing device may be configured as follows: the fabric is a pile fabric, the pile yarn woven into the base fabric of the pile fabric is in contact with the groove forming portion, and the pile yarn is in contact with the groove forming portion. Both ends in the axial direction of the developer carrying roller of the groove forming portion are in contact, and the front ends of the pile yarns face inward in the axial direction.

In this case, leakage of toner particles can be further properly prevented.

The image forming apparatus includes: an accommodating portion accommodating toner particles for developing a latent image carried on an image carrier; and a toner particle carrying roller having a surface on a surface for carrying the toner particles. Helical grooves inclined with respect to the axial direction and the circumferential direction and formed at equal intervals in the axial direction.

According to this image forming apparatus, the toner particles can be moved while rolling while the toner particle carrying roller rotates, so that the toner particles can be favorably charged. In addition, since the relative positions of the image carrier and the groove portion sequentially change in the axial direction and the circumferential direction as the toner carrying roller rotates, it is possible to suppress occurrence of density unevenness in the developed toner image.

[Overview of image forming apparatus]

Using FIGS. 1 and 2 , a laser printer 10 (hereinafter also referred to as a printer) will be used as an example to describe a configuration example and an example operation of an image forming apparatus that forms an image using a developing device as a developing device according to this embodiment. FIG. 1 is a schematic diagram of main components constituting the printer 10 , and FIG. 2 is a diagram for explaining the configuration of a control unit included in the printer 10 . In addition, the vertical direction is indicated by an arrow, for example, the paper feed tray 92 is arranged at the lower part of the printer 10 , and the fixing unit 90 is arranged at the upper part of the printer 10 .

<Structure of Printer 10>

As shown in FIG. 1, the printer 10 has along the rotation direction of a photoreceptor 20 as an example of an image bearing body bearing a latent image: a charging unit 30, an exposure unit 40, a developer holding unit 50 (also referred to as a YMCK developing unit). unit), a primary transfer unit 60, an intermediate transfer body 70, a cleaning unit 75, and also has a secondary transfer unit 80, a fixing unit 90, a display unit 95 composed of a liquid crystal panel as a notification unit to the user, and A control unit 100 that controls the above-mentioned units and the like and grasps the operation of the printer.

The photoreceptor 20 has a cylindrical conductive base material and a photosensitive layer formed on its outer peripheral surface, and is rotatable around a central axis. In this embodiment, it rotates clockwise as indicated by an arrow in FIG. 1 . .

The charging unit 30 is a device for charging the photoreceptor 20 , and the photoreceptor unit 40 is a device for forming a latent image on the charged photoreceptor 20 by irradiating laser light. The exposure unit 40 has a semiconductor laser for emitting a laser beam as light, a polygon mirror unit for rotating a polygon mirror, various lenses such as F-θ lenses, and the like. The exposure unit 40 modulates a laser beam based on an image signal input from an unillustrated host computer such as a personal computer, a word processor, and irradiates the modulated laser beam onto the charged photoreceptor 20 . At this time, the laser beam emitted from the semiconductor laser is irradiated onto the polygon mirror. The laser beam irradiated on the polygon mirror changes the reflection angle by the rotation of the polygon mirror, passes through the lens, and scans on the photoreceptor 20 . Then, by turning on (ON)/OFF (OFF) the laser beam at a predetermined timing, a dot-like latent image is formed on the grid-like regions on the photoreceptor 20 rotating at a predetermined speed. A latent image is constituted by these dot-like latent images. Here, since the dotted latent image forms a latent image, it cannot be seen with the naked eye.

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

In this embodiment, the developer holding unit 50 can move the positions of the four developers 51 , 52 , 53 , 54 by rotating. That is, the developer holding unit 50 holds the four developers 51 , 52 , 53 , 54 by four detachable parts (holding parts) 50 a , 50 b , 50 c , 50 d, and the four developers 51 , 52 , 53 , 54 can rotate around the central axis 50 a while maintaining the relative position therebetween. Whenever the image formation of one page is completed, the latent images formed on the photoreceptor 20 are sequentially developed by the toner contained in the respective developing units 51 , 52 , 53 , and 54 by selectively facing the photoreceptor 20 . In addition, each of the four developers 51 , 52 , 53 , 54 can be attached to and detached from the attachment and detachment portion of the developer holding unit 50 . In addition, each developer will be described in detail later.

The primary transfer unit 60 is a device for transferring the single-color toner image formed on the photoreceptor 20 to the intermediate transfer body 70. A full-color toner image is formed on the intermediate transfer body 70 . The intermediate transfer body 70 is an endless belt, and is driven to rotate at substantially the same peripheral speed as the photoreceptor 20 . The secondary transfer unit 80 is for transferring a single-color toner image or a full-color toner image formed on the intermediate transfer body 70 to a medium (recording medium) such as paper (recording paper), film, or cloth. installation.

The fixing unit 90 is used to thermally bond the single-color toner image or the full-color toner image transferred onto the recording 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 in contact with the surface of the photoreceptor 20 . After the toner image is transferred, the remaining toner T on the photoreceptor 20 is scraped off by the cleaning blade 76 .

As shown in FIG. 2 , the control unit 100 is composed of a main controller 101 and a unit controller 102. An image signal and a control signal are input to the main controller 101, and the unit controller 102 controls all units according to an instruction based on the image signal and the control signal. The above-mentioned respective units and the like are used to form an image.

The main controller 101 is electrically connected to a host computer through an interface 112, and has an image memory 113 for storing image signals input from the host computer, a CPU 111 serving for overall control of the printer 10, and the like.

The unit controller 102 has memory 116 such as CPU 120, RAM or ROM, and is used to drive control device main body each unit (charging unit 30, exposure unit 40, primary transfer unit 60, cleaning unit 75, secondary transfer unit 80, The respective drive control circuits of the fixing unit 90 , the display unit 95 ), and the developer holding unit 50 , etc., control the respective units based on signals input from the main controller 101 .

<Operation of Printer 10>

Next, the operation and other components of the printer 10 will be described.

First, when image signals and control signals from a host computer not shown in the figure are input to the main controller 101 of the printer 10 through the interface (I/F) 112, the unit controller 102 based on the information from the main controller 101 The photoreceptor 20 , the developing roller 510 provided on the developing devices 51 , 52 , 53 , and 54 , and the intermediate transfer body 70 are rotated by the command. The photoreceptor 20 is sequentially charged by the charging unit 30 at the charging position while rotating.

The charged area of the photoreceptor 20 reaches the exposure position as the photoreceptor 20 rotates, and a latent image corresponding to the image information of the first color, for example, yellow Y is formed by the exposure unit 40 . At this time, the developer holding unit 50 positions the yellow developer 54 accommodating yellow (Y) toner at a developing position opposite to the photoreceptor 20 .

The latent image formed on the photoreceptor 20 reaches a developing position as the photoreceptor 20 rotates, and the latent image is developed with yellow toner by the yellow developing device 54 . Thus, a yellow toner image is formed on the photoreceptor 20 .

The yellow toner image formed on the photoreceptor 20 reaches the primary transfer position as the photoreceptor 20 rotates, and is transferred onto 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 period, the photoreceptor 20 is in contact with the intermediate transfer body 70 , and the secondary transfer unit 80 is separated from the intermediate transfer body 70 .

By repeatedly performing the above-described processing for the second color, the third color, and the fourth color, the toner images of the four colors corresponding to the respective image signals are superimposedly transferred onto the intermediate transfer body 70 . Thus, a full-color toner image is formed on the intermediate transfer body 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 onto recording paper as a recording medium by the secondary transfer unit 80 . The recording paper is conveyed from the paper feed tray 92 to the secondary transfer unit 80 via the paper feed roller 94 and the registration roller 96 . In addition, when a transfer operation is performed, 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 onto the recording paper is heated and pressed by the fixing unit 90 to be thermally bonded to the recording paper. On the other hand, after the photoreceptor 20 passes the primary transfer position, the toner remaining (attached) on its surface is scraped off by the cleaning blade 76 to prepare for charging for forming the next latent image. The scraped-off toner is collected in a waste toner storage portion (residual toner collection portion) included in the cleaning unit 75 .

【Overview of the developer】

Next, an example of the configuration of the processor will be described with reference to FIGS. 3 to 5 . Fig. 3 is a perspective view of a yellow developer. Fig. 4 is a cross-sectional view showing main constituent parts of a yellow developer. Fig. 5 is a perspective view showing a developing device with a developing roller removed. The cross-sectional view shown in FIG. 4 is a view showing a cross-section of the yellow developing device taken along a plane perpendicular to the longitudinal direction shown in FIG. 3 . In addition, in FIG. 4 , as in FIG. 1 , the vertical direction is indicated by arrows. For example, the central axis of the developing roller 510 is located lower than the central axis of the photoreceptor 20 . In addition, FIG. 4 shows a state where the yellow developing device 54 is located at a developing position facing the photoreceptor 20 .

In the developing device holding unit 50, there are provided a black developing device 51 containing black (K) toner, a magenta developing device 52 containing magenta (M) toner, and a cyan developing device 52 containing cyan (C) toner. A device 53, and a yellow developing device 54 containing yellow (Y) toner. Since the respective developing devices have the same structure, the yellow developing device 54 will be described below.

<Structure of Yellow Developer 54>

The yellow developing device 54 has a housing 540 for accommodating toner, a developing roller 510 as an example of a toner particle carrying roller for carrying toner, a toner roller for supplying toner to the developing roller 510 The supply roller 550 , the regulating blade 560 as an example of a layer thickness regulating member for regulating the layer thickness of the toner carried on the developing roller 510 , and the gap between the housing 540 and the upper side of the developing roller 510 are sealed. The upper seal 520 , the end seal 527 for sealing the gap between the housing 540 and the end side of the developing roller 510 , and the like.

The case 540 is manufactured by welding an integrally formed resin upper case portion 542 and a lower case portion 544 , and has a toner containing portion 530 , which is a container for containing the toner T, formed therein. The toner accommodating portion 530 is divided into two toner accommodating portions, that is, a first toner accommodating portion, by a partition wall 545 protruding from the inner wall inwardly (up and down direction in FIG. 4 ) for partitioning the toner T. 530a and the second toner containing portion 530b.

The upper parts 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. 4 . However, when the developer holding unit 50 is rotated, the toners accommodated in the first toner accommodating portion 530a and the second toner accommodating portion 530b are temporarily collected in the communication portion on the upper side of the developing position, and are restored to the normal state after being restored. When reaching the state shown in FIG. 4, these toners are mixed and returned to the first toner accommodating portion 530a and the second toner accommodating portion 530b. That is, the toner T in the developing device is stirred by the rotation of the developing device holding unit 50 . Therefore, in the present embodiment, a stirring member is not provided in the toner container 530 , but a stirring member for stirring the toner T contained in the toner container 530 may be provided. As shown in FIG. 4 , the housing 540 has an opening 572 at its lower portion, and a developing roller 510 , which will be described later, is provided facing the opening 572 .

The toner supply roller 550 is composed of an elastic roller portion 550 a formed of, for example, urethane foam, and a shaft body 550 b as a rotation center of the roller portion 550 a. The toner supply roller 550 is supported by the casing 540 via both ends of the shaft body 550b so as to be freely rotatable around the shaft body 550b. The roller portion 550 a is accommodated in the first toner accommodating portion 530 a (inside the housing 540 ) of the housing 540 , and supplies the toner T accommodated in the first toner accommodating portion 530 a to the developing roller 510 . . The toner supply roller 550 is disposed vertically below the first toner containing portion 530a. The toner T accommodated in the first toner accommodating portion 530a is supplied to the developing roller 510 by the toner supply roller 550 at the lower portion of the first toner accommodating portion 530a. In addition, the toner supply roller 550 peels off the remaining toner T remaining on the developing roller 510 after development from the developing roller 510 .

The toner supply roller 550 and the developing roller 510 are mounted on the casing 540 in a state of being pressed against each other. Therefore, the roller portion 550 a of the toner supply roller 550 abuts against the developing roller 510 in an elastically deformed state. The toner supply roller 550 rotates in a direction (clockwise in FIG. 4 ) opposite to that of the developing roller 510 (counterclockwise in FIG. 4 ). The shaft body 550 b is located at a position lower than the rotation center axis of the developing roller 510 .

The developing roller 510 carries the toner T and conveys it to a developing position opposite to the photoreceptor 20 . The developing roller 510 is made of metal, and can be made of aluminum alloys such as 5056 aluminum alloy or 6063 aluminum alloy, or iron alloys such as STKM, and can be nickel-plated or chrome-plated as required. On the surface of the developing roller 510 , a groove-like concave portion (helical groove portion) formed in a helical shape is provided at the central portion in the axial direction of the developing roller 510 . The surface shape of the developing roller 510 will be described in detail later.

In addition, as shown in FIG. 3 , the developing roller 510 is supported at both end portions in the longitudinal direction, and is rotatable around a central axis. As shown in FIG. 4 , the developing roller 510 rotates in a direction (counterclockwise in FIG. 4 ) opposite to the rotation direction of the photoreceptor 20 (clockwise in FIG. 4 ). Its central axis is at a position lower than that of the photoreceptor 20 .

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

The regulating blade 560 abuts on the developing roller 510 over the entire area from one end to the other end in the axial direction of the developing roller 510 , applies charges to the toner T carried on the developing roller 510 , and restricts the toner T carried on the developing roller 510 . The layer thickness of the toner T on the roller 510. This regulation scraper 560 has a rubber part 560a and a rubber support part 560b. The rubber portion 560a is made of silicone rubber, urethane rubber, or the like, and the rubber support portion 560b is an elastic thin plate made of phosphor bronze, stainless steel, or the like. The rubber part 560a is provided along the longitudinal direction of the rubber support part 560b and is supported on one end side of the width direction of the rubber support part 560b. The limiting scraper is attached to the casing 540 by supporting the metal plate 562 . In addition, a blade back surface member 570 made of Moltopren or the like is provided on the side opposite to the developing roller 510 of the regulating blade 560 .

Here, the rubber portion 560a is pressed against the entire region of the developing roller 510 from the central portion to both end portions by the elastic force generated by the bending of the rubber supporting portion 560b. In addition, the blade back member 570 prevents the toner T from entering between the rubber bearing 560b and the housing 540, thereby keeping the elastic force generated by the bending of the rubber bearing 560b stable, and passes the toner T from the front and back of the rubber bearing 560a toward the developing roller. The direction of 510 presses the rubber portion 560 a to press the rubber portion 560 a against the developing roller 510 . Therefore, the blade back surface member 570 improves the contact uniformity when the rubber portion 560 a contacts the developing roller 510 .

The end portion of the regulating blade 560 opposite to the side supported by the blade supporting metal plate 562, that is, the front end does not come into contact with the developing roller 510, but is in contact with the developing roller 510 by a predetermined distance from the front end. 510 contact. In other words, the regulating blade 560 does not abut against the developing roller 510 at the edge, but abuts at the middle through the flat surface of the rubber portion 560 a. In addition, the restriction blade 560 is arranged so that the front end 560 a faces the upstream side in the rotation direction of the developing roller 510 , that is, so-called reverse abutment. The abutting position of the regulating blade 560 on the developing roller 510 is lower than the central axis of the developing roller 510 and higher than the central axis of the toner supply roller 550 .

In addition, the rubber support portion 560b is provided longer than the rubber portion 560a in the axial direction of the developing roller 510, and extends outward from both ends of the rubber portion 560a. The extended portion of the rubber support portion 560b is provided with an end seal 527 thicker than the rubber portion 560a, for example, made of non-woven fabric, and the end seal 527 is bonded to the portion where the rubber portion 560a is bonded. on the same surface as the surface. At this time, the axial end surface of the rubber portion 560 a abuts against the side surface of the end seal 527 .

The end seal 527 contacts the developing roller 510 along its peripheral surface, thereby preventing toner from leaking out from between the peripheral surface and the casing 540 . The end seals 527 are provided so as to abut against both ends of the surface of the developing roller 510 not provided with grooves when the developing roller 510 is mounted, and have a width extending from the ends of the developing roller 510 to the outside. In addition, the end seal 527 extends a sufficiently long length from the front end of the rubber portion 560 a of the regulating blade 560 . When the restricting blade 560 is mounted on the casing 540 , the end seal 527 is formed along a portion of the casing 540 facing the outer peripheral surface of the developing roller 510 and closes a gap between the casing 540 and the developing roller 510 .

The upper seal 520 prevents the toner T in the yellow developing device 54 from leaking outward, and recovers the toner T on the developing roller 510 passing through the developing position into the developing device without scraping it off. The upper seal 520 is made of polyethylene film or the like. The upper seal 520 is supported by a seal support metal plate 522 and mounted on the housing 540 via the seal support metal plate 522 . Also, a seal pressing member 524 made of Moltopren or the like is provided on the opposite side of the upper seal 520 from the side of the developing roller 510 , and the upper seal 520 is pressed against the developing roller 510 by the elastic force of the seal pressing member 524 . The contact position where the upper seal 520 contacts the developing roller 510 is located higher than the central axis of the developing roller 510 .

<Operation of Yellow Developing Device 54>

In the yellow developing device 54 configured as above, the toner supply roller 550 supplies the toner T accommodated in the toner accommodating portion 530 to the developing roller 510 . The toner T supplied to the developing roller 510 reaches the abutting position of the regulating blade 560 as the developing roller 510 rotates, and when passing through the abutting position, is charged and the layer thickness is regulated.

The charged toner T on the developing roller 510 reaches a developing position opposite to the photoreceptor 20 through further rotation of the developing roller 510, and is supplied to the photoreceptor 20 at the developing position under the action of an alternating electric field to form development of the latent image. The toner T on the developing roller 510 that has passed the developing position as the developing roller 510 further rotates passes through the upper seal 520 and is recovered into the developing device by the upper seal 520 without being scraped off. In addition, the toner T still remaining on the developing roller 510 is peeled off by the toner supply roller 550 .

[Surface shape of developing roller 510 ]

Fig. 6 is a schematic view for explaining the surface shape of the developing roller. FIG. 7 is a cross-sectional view for explaining a cross-section of the developing roller cut at a plane passing through the shaft. In FIG. 6 , the groove portion on the surface of the developing roller 510 is shown as a straight line for convenience, but since the groove portion is formed in a spiral shape, it should be seen as a curved line precisely.

The central portion 510 a in the axial direction of the developing roller 510 is provided with a concave-convex portion for supporting toner particles, and both end portions 510 b have smooth peripheral surfaces against which the end seals 527 can be attached.

As shown in FIG. 6, a spiral groove portion 511 is formed on the central portion 510a of the developing roller 510 of the present embodiment, and the groove portion 511 is inclined with respect to the axial direction and the circumferential direction of the developing roller 510 and is arranged in the axial direction. Formed at equal intervals. Here, two kinds of the groove portions 511 are formed with different inclination angles with respect to the axial direction and the circumferential direction of the developing roller 510 . The two types of grooves 511 intersect each other to form a grid, and the top surface 512 a of the convex portion 512 surrounded by the two types of grooves 511 is approximately formed in a square. In addition, the two kinds of groove portions 511 are formed in such a manner that one of the two diagonals of the square shape of the top surface 512 a of the convex portion 512 is along the circumferential direction.

That is, one of the two kinds of groove portions 511 is formed in a spiral shape at an angle of 45° in the clockwise direction with respect to the axis of the developing roller 510 , and the other is formed at an angle of 45° in the counterclockwise direction with respect to the axis of the developing roller 510 . ° angle of the helix. Therefore, the intersection angle between one groove portion 511a and the other groove portion 511b is 90°. In addition, since one groove portion 511a and the other groove portion 511b are equally spaced in the axial direction of the developing roller 510, the shape of the top surface 512a of the convex portion 512 surrounded by the two types of groove portions is approximately square.

As shown in FIG. 7 , two kinds of groove portions 510 are respectively formed at intervals of 80 μm in the axial direction of the developing roller 510 , and the angle of the inclined portion 511 d from the top surface 512 a of the convex portion 512 to the bottom surface 511 c of the groove portion 511 is according to It is formed in such a manner that the intersection angle α of a virtual plane formed by extending the two slopes forming the groove portion 511 in the direction of the axis C is 90°.

In addition, the depth of the groove portion 511 , that is, the distance from the top surface 512 a of the convex portion 512 to the bottom surface 511 c of the groove portion 511 is constant and is about 7 μm. Here, the volume average particle diameter of the toner is about 5 to 10 μm, and the depth of the groove portion 511 is set to be equal to or less than twice the volume average particle diameter of the toner.

The developing roller 510 described above is formed by roll forming. FIG. 8 is a diagram for explaining a state in which a developing roller is formed by roll forming. FIG. 9 is a diagram illustrating a process of forming a developing roller.

The developing roller 510 is formed of a cylindrical hollow material.

First, the cylindrical member 515 is cut out by cutting a cylindrical material to a length capable of forming the central portion 510 a for carrying the toner and the end portion 510 b abutting the end seal 527 ( S001 ). Step portions 510 c ( FIG. 6 ) are formed on the cylindrical member 515 by cutting, and flanges 513 having shafts of the developing roller 510 are fitted into the inner peripheral portions of both ends ( S002 ). Here, the flange 513 has: a disc-shaped flange main body 513a having a diameter capable of being pressed into the formed stepped portion 510c; and a shaft portion 513b protruding from the center of the flange 513 perpendicular to the disc surface. .

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

Then, the cylindrical member 515 fitted with the flange 513 is rotated around the axis while the shaft portions 513b at both ends are supported, and the entire outer peripheral surface of the cylindrical member 515 is slightly cut so that the entire surface The area is concentric with the axis, that is, has a fixed distance from the axis, and the surface of the cylindrical member 515 is ground, thereby forming the non-roll-formed developing roller 509 (S004).

The cylindrical member 515 whose surface has been ground is roll-formed by an apparatus having two kinds of dies 900 as processing tools as shown in FIG. S005). In the roll forming device, when the two types of molds 900 arranged at opposite positions rotate in the same direction, a mechanism (here, the non-rolled forming processing developing roller 509) is arranged, and the two types of molds 900 are pressed against the non-rolled forming process. The developing roller 509 is shaped, and the unrolled shaped developing roller 509 is rotated in the opposite direction to the die 900 and conveyed in the axial direction. Blades 900a for forming the above-mentioned groove portions 511a, 511b are respectively provided on the mold 900, and each blade 900a is provided obliquely so that the groove portions 511a, 511b formed by each blade are formed on the surface of the developing roller 509 without roll forming. Straight ahead on the surface. Here, the portion where the die 900 abuts against the surface of the non-roll forming developing roller 509 is used as the edge 900a, and the recesses are formed by pressing and rolling the parts without actively cutting the parts during the roll forming. In addition, during the roll forming, the mold 900 is not brought into contact with the both ends 510b of the non-roll formed developing roller 509, so that the both ends 510b have smooth surfaces without irregularities. That is, the top surface 512a of the convex portion 512 not in contact with the die 900 in the central portion 510a and the both end portions 510b not to be processed by roll forming are positioned at the same distance L from the axis C. Then, the surface 510d of the developing roller 510 is basically covered by the bottom surfaces 511c of the grooves 511a, 511b recessed in contact with the mold 900 and the non-processed surface not in contact with the mold 900 .

If necessary, for example, the developing roller 510 formed by roll forming may be subjected to electroless Ni—P plating, electroplating, hard chrome plating, and the like.

The toner is supplied from the toner supply roller 550 between the end seals 527 abutting on both end portions 510 b of the developing roller 510 , and the toner layer is regulated at the pressing position of the regulation blade 560 . layer thickness. At this time, the restriction blade 560 is pressed by the entire area from the both end portions 510b to the central portion 510a of the developing roller 510, but since the both end portions 510b of the developing roller 510 and the top surface 512a of the convex portion 512 are away from the axis C Since the distance L is fixed, the restricting blade 560 presses the developing roller 510 in an approximately flat state without large bending. Therefore, for example, the regulating blade 560 abutting against the entire region from the central portion 510 a to both end portions 510 b of the developing roller 510 abuts in an approximately flat state without much bending in the axial direction. That is, since the regulating blade 560 does not bend greatly, it is possible to prevent a very large gap from being generated between the developing roller 510 and the regulating blade 560 .

In addition, since the top surfaces 512a of the protrusions 512 arranged on the surface 510d of the developing roller 510 with the grooves 511 as recesses therebetween are located at a fixed distance L away from the axis C, each protrusion 512 The top surface 512a of the developing roller 510 is located on the peripheral surface formed with a single diameter. Therefore, for example, when the flat surface of the regulating blade 560 is pressed toward the developing roller 510 side in order to restrict the layer thickness of the carried toner particles T, due to the toner carried on the top surface 512 a of each convex portion 512 The toner particles are also pressed, so the layer thickness of the toner particles T carried on the developing roller 510 can be made substantially uniform over the entire area of the developing roller 510 .

And, since the distance from the top surface 512a of the convex portion 512 to the bottom surface 511c of the groove portion 511 is not more than twice the volume average particle diameter, it is possible to make the toner that enters between the developing roller 510 and the regulating blade 560 The layer thickness of the toner layer formed by the toner particles is about two toner particles or less. That is, a large amount of toner particles do not enter into the groove portion 511, and when pressed by the regulating blade 560, almost all of the toner particles come into contact with the surface 510d of the developing roller 510 and the surface of the regulating blade 560. one of the contacts. Therefore, the individual toner particles T are easily rolled by the same pressure, and the toner particles are less likely to stay in the groove portion 511, so that the toner particles T can be uniformly and well charged. Therefore, the toner particles are reliably carried on the developing roller 510 for development, and in addition, a very large gap is not generated between the surface 510d of the developing roller 510 and the regulating blade 560, so that the toner particles can be prevented from Leaks to the outside of the developers 51, 52, 53, 54.

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

In particular, the depth of the groove portion 511 of the developing roller 510 of the present embodiment is 7 μm, which is approximately double the volume average particle diameter of the toner particles T. Therefore, since the regulating blade 560 is made of rubber and follows the unevenness of the surface 510d of the developing roller 510, the toner particles T do not overlap, and a thickness equivalent to one toner particle can be formed on the entire surface of the developing roller 510. toner layer. By forming a toner layer with a thickness of one grain on the surface 510d of the developing roller 510, each toner particle T can be reliably charged over the entire area including the convex portion 512 and the groove portion 512 of the central portion 510a, and the It is reliably carried on the developing roller 510, so that the transferability at the time of development can be improved, and also the toner can be prevented from leaking out of the developing device.

That is, if irregularities in size, depth, shape, etc. are formed on the surface 510d of the developing roller 510, the toner particles that have entered the deep recesses among the carried toner particles are difficult to roll, and thus difficult to be charged. . In addition, when the groove portions are formed at predetermined intervals in the axial direction and along the circumferential direction, even if the photoreceptor 20 rotates, the axial position of the photoreceptor 20 facing the groove portions does not change. In the developed toner image, only the portion facing the groove portion may become denser. On the other hand, when the groove portion is formed in the axial direction, since the rotation direction of the toner particle carrying roller is almost perpendicular to the direction of the groove portion, the carried toner particles are difficult to roll and thus hard to be charged.

According to the developers 51 , 52 , 53 , 54 and the developing roller 510 of this embodiment, since the surface 510 d of the developing roller 510 is formed with spiral grooves inclined with respect to the axial direction and the circumferential direction and equally spaced in the axial direction. 511, so the toner particles T can be rolled and moved simultaneously with the rotation of the developing roller 510, so the toner particles T can be charged well. In addition, since the position of the photoreceptor 20 relative to the groove portion 511 changes sequentially in the axial direction and the circumferential direction as the developing roller 510 rotates, it is possible to suppress occurrence of density unevenness in the developed toner image.

In addition, since two kinds of grooves 511 a and 511 b having different inclination angles are formed on the developing roller 510 of this embodiment, the toner particles T move in two directions along the grooves 511 a and 511 b. Therefore, it is possible to prevent the toner particles T from being displaced by moving only in one predetermined direction. In addition, since the two kinds of grooves 511a and 511b intersect each other to form a grid, the toner particles T that have rolled along one groove 511a (511b) may also roll along the other groove 511b on the way. (511a) while scrolling. Therefore, it is possible to further effectively suppress the deviation of the moving direction of the toner particles T.

And, since the top surface 512a of the convex portion 512 surrounded by the two kinds of groove portions 511 is a square, and one diagonal line of the square is along the circumferential direction, the two apex angles of the convex portion 512 along the circumferential direction, And the two apex angles along the axial direction are both right angles, and the two types of groove portions 511a, 511b are inclined at the same angle with respect to the circumferential direction and the axial direction. Therefore, it is possible to constitute a structure in which the toner particles T can easily move both in the circumferential direction and in the axial direction. Therefore, the toner particles can be rotated more uniformly, thereby being charged more uniformly.

In addition, since the layer thickness of the toner particles T carried on the surface of the developing roller 510 is regulated by the plane of the rubber portion 560 a of the regulating blade 560 , the surface of the developing roller 510 , especially the toner particles carried by the convex portion 512 The toner particles T are not completely scraped off by the regulating blade 560 . That is, the layer thickness of the toner particles T can be restricted in a state where both the groove portions 511 and the convex portions 512 of the developing roller 510 carry the toner particles T. In addition, since the toner particles T carried on the surface 510d are pressed by the flat surface of the regulating blade 560, the surface of the developing roller 510, one of the regulating blades 560, and the toner particles or toner The toner particles T are well charged by rubbing the toner particles against each other.

As described above, the laser printer forms a latent image on the photoreceptor 20 using a laser beam, and develops the formed latent image with the toner carried on the developing roller 510 . At this time, a dot-like latent image, ie, a screen, is formed in areas divided into grids on the photoreceptor 20 by turning on/off the laser beam scanned in the main scanning direction (axial direction). A latent image is constituted by these dot-like latent images.

In addition, in the case of the developing roller 510 having clearly differentiated groove portions (recesses) 511 and protrusions 512 as in the present embodiment, there may be more toner particles than the protrusions 512, for example. T enters into the groove portion 511 . At this time, in the toner image, the density of the portion developed by the groove portion 511 and the portion developed by the convex portion 512 may be different. In particular, although the effect is small for small-area images such as characters and lines, density unevenness may be conspicuous for large-area images such as photographs and illustrations. Such a phenomenon is more remarkable when the pitch of the groove portions 511 formed on the developing roller 510 in the axial direction is larger than the pitch of the grids of the above-mentioned screen in the main scanning direction. This is because even dots that should be originally formed at the same density have different densities depending on whether they are developed by the grooves 511 of the developing roller 510 or by the protrusions 512 .

Therefore, in the developing roller 510 of this embodiment, the pitch in the axial direction of the grooves 511 formed on the developing roller 510 is set to be smaller than the maximum pitch of the grid when forming an image with a large area such as a photograph or an illustration. Here, the pitch of the lattice in the main scanning direction of the latent image when forming an image having a large area such as a photograph or an illustration is not the pitch between dots in an image of the highest resolution that can be formed by a laser printer. This is because when a laser printer is used to form a large-area image such as a photograph or an illustration, dots are formed at a resolution lower than the highest resolution of the printer, and each dot is given a gradation, thereby improving the overall image quality. image quality.

FIG. 11 is a diagram for explaining pitches in screens and latent images. As shown in Figure 11, for example, when the highest resolution of the printer is 600dpi (the pitch is 42.5μm), if the resolution of the latent image is 600dpi, the area where the dot-like latent image can be formed is divided into 42.5μm pitch lattice. Therefore, each divided region can only have or not have dot-like latent images, but cannot express tone (the upper part of FIG. 11 ).

Therefore, when forming an image with a large area, for example, three dot latent images in a resolution of 600dpi are taken as one dot latent image, and the semiconductor laser can respond to three dot latent images at a resolution of 600dpi Change the time length of the emitted laser beam within a certain period of time, thereby expressing the tone (lower part of Figure 11). At this time, the resolution when forming an image having a large area is 200 dpi, and the area where a dot-like latent image can be formed is divided into a grid with a pitch of 127.5 μm. Therefore, in the developing roller 510 of this embodiment, by setting the pitch of the groove portion 511 in the axial direction to 80 μm, each dot of the latent image formed in the grid-like region divided into 200 dpi, that is, the pitch of 127.5 μm can be made The shape latent images are all developed through the portion including the groove portion 511 and the convex portion 512 of the developing roller 510, thereby suppressing density unevenness of the developed toner image. In this embodiment, an example is described in which the maximum resolution of a laser printer is set to 600 dpi, and the area that can form a dot-like latent image when forming an image such as a photograph is divided into grid-like areas. The axial pitch of the developing roller 510 was set to 127.5 μm, and the axial pitch of the groove portion 511 of the developing roller 510 was set to 80 μm. But not limited to this example. The pitch in the axial direction of the grooves 511 of the developing roller 510 may be smaller than the pitch in the axial direction of areas divided into grids where dot-like latent images are formed in latent images such as photographs. In addition, in particular, when the maximum distance in the axial direction between adjacent groove portions 511 and convex portions 512 is smaller than the area divided into grids where dot-like latent images can be formed, since one dot-like latent image passes at least Since one groove portion 511 and one convex portion 512 are developed, density unevenness of a large-area image can be effectively suppressed. For example, when the maximum width of the groove portion 511 in the axial direction is 40 μm, and the maximum width of the convex portion 512 in the axial direction is 40 μm, since it is divided into grids with a pitch of 127.5 μm, a dot-like latent image can be formed. A groove portion 511 and a convex portion 512 are included in the region, so the density unevenness of a large-area image can be effectively suppressed.

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

In the developing roller 510 of the first modified example, the top surface 512a of the convex portion 512 surrounded by the two types of groove portions 511 is formed into a rhombus shape, and one of the two diagonal lines of each rhombus shape The groove portion is formed in a circumferential manner. In the developing roller 510 of the first modified example, since the recesses are also formed by the above-mentioned roll forming, the protrusions 512 that are not in contact with the mold 900 are arranged on the central portion 510 a of the developing roller 510 with the recesses interposed therebetween. The top surfaces 512a and the top surfaces 512a and both end portions 510b not to be roll-formed are located equidistant from the axis C. As shown in FIG.

According to this developing roller 510, since the groove portion 511 is formed so that one of the two diagonal lines of each rhombus is along the circumferential direction, the two types of groove portions 511 are arranged from one direction along the circumferential direction to the other. One vertex of the diagonal line is inclined at the same angle to both ends of the axial direction. Therefore, the toner particles T moving along the two types of groove portions 511 move almost equally toward both ends in the axial direction, so that the toner particles can move uniformly, which is consistent with the top surface of the convex portion 512. The case where 512a is a square is the same. And, when the longer diagonal line of the two diagonals of the rhombus-shaped convex portion 512 on the top surface 512a is along the circumferential direction, the two apex angles along the circumferential direction of the rhombus-shaped convex portion 512 on the top surface 512a are form an acute angle, and the two vertex angles along the axis form an obtuse angle. Therefore, it is possible to constitute a structure in which toner particles move more easily in the circumferential direction.

In addition, as shown in FIG. 13 , when the shorter diagonal line of the two diagonals of the rhombus-shaped convex portion 512 on the top surface 512a is along the circumferential direction, the two diagonal lines of the rhombus-shaped convex portion on the top surface along the circumferential direction The first vertex angle forms an obtuse angle, and the two vertex angles along the axial direction form an acute angle. In the developing roller 510 of the second modified example, since the recesses are also formed by the above-mentioned roll forming, the protrusions 512 that are not in contact with the mold 900 are arranged on the central portion 510 a of the developing roller 510 with the recesses interposed therebetween. The top surfaces 512a and the top surfaces 512a of the convex portion 512 not in contact with the mold 900 on the central portion 510a and both end portions 510b not subject to roll forming are located equidistant from the axis C.

Therefore, it is possible to constitute a structure in which the toner particles are more likely to move in the axial direction, so that the toner particles can be better dispersed over the entire area of the developing roller 510 .

In this embodiment, an example in which two types of grooves 511a, 511b are provided on the surface of the developing roller 510 has been described, but there may be only one type of grooves as in the third modified example shown in FIG. 511. In the developing roller 510 of the third modified example, since the concave portions are also formed by the above-mentioned roll forming, the convex portions 512 that are not in contact with the mold 900 are arranged on the central portion 510 a of the developing roller 510 with the concave portions interposed therebetween. The surfaces, the surface of the convex portion 512 not in contact with the die 900 on the central portion 510a, and both end portions 510b not to be subjected to roll forming are located at positions equidistant from the axis C.

At this time, although there is an effect of moving the toner particles in a predetermined direction and charging them, it is possible to charge the toner particles well and further disperse them over the entire area of the developing roller 510. In other words, the effect of the developing roller 510 of the above embodiment having two types of groove portions 511a, 511b is more excellent.

[Other Embodiments (Second Embodiment to Fourth Embodiment, etc.)]

The developing device and the like according to the present invention have been described above based on the above-mentioned embodiments, but the above-mentioned embodiments of the invention are only for making the present invention easier to understand, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and of course equivalents thereof are also included in the present invention.

In the above-mentioned embodiments, an image forming apparatus has been described taking a full-color laser printer as an example, but the present invention can also be applied to various image forming apparatuses such as monochrome laser printers, copiers, and facsimile machines.

In addition, in the above-mentioned embodiment, the example in which the printer has a plurality of attaching and detachable parts is shown, but it may also have a structure such as a cover unit in which only one attaching and detachable part is provided by inserting the developing device to be attached. and can be turned off. In addition, in the above-mentioned embodiments, an image forming apparatus having a rotary developing device has been described as an example, but the present invention is not limited thereto. For example, the present invention can also be applied to an image forming apparatus having a tandem developing device.

In addition, the photoreceptor is not limited to a photosensitive roller configured by providing a photosensitive layer on the outer peripheral surface of a cylindrical conductive base material, and may be formed by providing a photosensitive layer on the surface of a belt-shaped conductive base material. photosensitive belt.

In addition, as another preferred embodiment, the following second embodiment and fourth embodiment can be mentioned.

[Second Embodiment]

<<Structure Example of the Developing Roller 510 of the Developing Device of the Second Embodiment>>

Here, a configuration example of the developing roller 510 of the developing device according to the second embodiment will be described with reference to FIGS. 15 to 18 . FIG. 15 is a schematic perspective view of the developing roller 510, showing the spiral first groove 1518a and the second groove 1518b with different winding directions. FIG. 16 is a schematic front view of the developing roller 510 , showing the positional relationship of the uneven processed portion 1512 , the non-embossed processed portion 1514 , and the intermediate portion 1516 of the developing roller 510 . FIG. 17 is a schematic diagram of the cross-sectional shape of the trench 1518 . FIG. 18 is a schematic cross-sectional view AA of FIG. 16 , showing the difference between the depth of the groove 1518 of the concave-convex processed part 1512 and the depth of the groove 1518 of the middle part 1516 . In FIGS. 15 to 18 , the scales of the grooves 1518 and the like are different from actual ones in order to make the drawings easier to understand. In addition, FIG. 17 shows a cross section along the direction indicated by symbol X in FIG. 16 .

The developing roller 510 of the developing device according to the second embodiment carries the toner T and conveys it to a developing position facing the photoreceptor 20 . The developing roller 510 is a member made of aluminum alloy, iron alloy, or the like. As shown in FIG. 16 and FIG. 18 , the developing roller 510 is mainly divided into three parts (a concave-convex processed part 1512 , a non-concave-convex processed part 1514 , and an intermediate part 1516 ) according to the difference in surface structure.

The concave-convex processed part 1512 is a part located in the central part in the axial direction of the developing roller 510, and its surface is concave-convex processed in order to properly support the toner T (both the convex part and the concave part of the concave-convex processed part 1512 serve as function as a toner carrying portion that carries toner). In the present embodiment, the above-mentioned roll forming process is used for the uneven processing, and the concave and convex portions are formed on the surface of the unevenly processed part 1512 by the roll forming process. More specifically, grooves 1518 are formed on the surface of the concave-convex part 1512 by roll forming, whereby the concave-convex part 1512 has the groove 1518 as a concave part and the non-groove part 1519 as a convex part.

In the present embodiment, as shown in FIGS. 15 and 16 , as the grooves 1518 , helical first grooves 1518 a and second grooves 1518 b whose winding directions are different from each other are provided. The acute angle formed by the length direction of the first groove 1518a and the axial direction and the acute angle formed by the length direction of the second groove 1518b and the axial direction are both about 45 degrees. In addition, as shown in FIG. 17 , the width and depth of the groove 1518 are about 80 μm and 7 μm, respectively, and the groove angle (the angle represented by symbol α in FIG. 17 ) is about 90 degrees. In addition, in the present embodiment, the toner T is in the form of particles (particles), and since the volume average particle diameter of the toner T is about 7 μm, the depth of the groove 1518 is related to the volume average particle diameter of the toner T. are approximately equal in size.

In addition, the surface of the concave-convex processed portion 1512 was subjected to electroless Ni—P plating.

The non-concave-convex portion 1514 is a portion not subjected to the above-described concavo-convex processing (roll forming process) on its surface. The non-roughened portion 1514 is located at both ends in the axial direction of the developing roller 510 , and its surface is in a smooth state (the ten-point average roughness Rz of the surface is 1 μm or less). Unlike the roughened portion 1512, the surface of the non-roughened portion 1514 is not subjected to electroless Ni—P plating.

The intermediate portion 1516 is a portion located between the uneven processing portion 1512 and the non-rough processing portion 1514 in the axial direction of the developing roller 510 , and has a different surface structure from the uneven processing portion 1512 and the non-rough processing portion 1514 .

That is, as shown in FIG. 16 , spiral grooves 1518 (first grooves 1518 a and second grooves 1518 b ) are formed on the surface of the intermediate portion 1516 by roll forming similarly to the uneven processing portion 1512 , However, as shown in FIG. 18 , the depth of the groove 1518 is different from the depth of the groove 1518 of the concave-convex part 1512 . In addition, unlike the concave-convex processed portion 1512, the surface thereof is not subjected to electroless Ni—P plating.

The difference in groove depth is explained more specifically. According to Fig. 18, it can be seen that the depths of all the grooves 1518 formed on the surface of the middle part 1516 are smaller than the depths of the grooves 1518 formed on the surface of the uneven processing part 1512 (in Fig. 18, only three are shown for shoulders). grooves 1518 on the middle portion 1516, but actually more than three grooves 1518 are provided on the middle portion 1516). In addition, among the grooves 1518 formed on the surface of the intermediate portion 1516, the depth of the groove 1518 on the side of the concave-convex processing portion 1512 of the intermediate portion 1516 is large, while the depth of the groove 1518 on the side of the non-concave-convex processing portion 1514 is large. depth is small). Furthermore, the closer to the non-concave-convex processed portion 1514, the smaller the depth of the groove 1518 (in other words, the closer to the concavo-convex processed portion 1512, the greater the depth of the groove 1518).

Here, the radii of the uneven processed portion 1512 , the non-uneven processed portion 1514 , and the intermediate portion 1516 are considered. As described above, in the present embodiment, since the groove 1518 is formed by the roll forming process (non-cutting process), the non-groove portion 1519 is raised by the roll forming process (in FIG. The raised part raised by forming processing is marked with oblique lines). Therefore, the radius r2 (of the non-groove portion 1519 ) of the uneven portion 1512 and the radii r3 , r4 , r5 (of the non-groove portion 1519 ) of the intermediate portion 1516 are larger than the radius r1 of the non-groove portion 1514 . In addition, the deeper the groove 1518 is, the larger the raised portion is. Therefore, the radius r2 (of the non-groove portion 1519 ) of the uneven portion 1512 is larger than the radii r3 , r4 , and r5 (of the non-groove portion 1519 ) of the intermediate portion 1516 .

That is, the intermediate portion 1516 has a radius smaller than the maximum radius of the uneven portion 1512 (that is, the radius of the non-groove portion 1519 ) and larger than the radius of the non-uneven portion 1514 .

In addition, as described above, among the grooves 1518 formed on the surface of the intermediate portion 1516, the depth of the grooves 1518 on the side of the concave-convex processing portion 1512 of the intermediate portion 1516 is large, while the depth of the grooves 1518 on the side of the non-concave-convex processing portion 1514 is large. The groove 1518 has a small depth. Also, the closer to the non-concave-convex processed portion 1514, the smaller the depth of the groove 1518 becomes. Therefore, the radius of the middle portion 1516 is larger (radius r5 ) on the side of the roughened portion 1512 of the middle portion 1516 , and smaller (radius r3 ) on the side of the non-roughened portion 1514 of the middle portion 1516 . In addition, the radius of the intermediate portion 1516 becomes gradually smaller from the side of the concave-convex processed portion 1512 to the side of the non-concave-convex processed portion 1514 (radius r5>radius r4>radius r3).

As described above, in the developing roller 510 of the present embodiment, the depths of the grooves 1518 in the concave-convex portion 1512 and the intermediate portion 1516 are different. When carrying out above-mentioned roll forming processing, can make the depth of groove 1518 different by changing the pressing force that mold is pressed to non-roll forming process developing roller (when wanting to make the depth of groove 1518 little, can reduce by pressure, when the depth of the groove 1518 is to be increased, the pressing force can be increased).

<<Effectiveness of the developer of the second embodiment>>

As described above, the developing device of the present embodiment has the developing roller 510 for carrying toner and the regulating blade 560 . The developing roller 510 has: a concave-convex processed portion 1512 located at the central portion in the axial direction of the developing roller 510 , the surface of which is concave-convex processed for carrying toner; The axial direction of the developing roller 510 is located between the concave-convex processed part 1512 and the non-convex-convex processed part 1514, and the intermediate part 1516 has The radius is smaller than the maximum radius of the uneven processing part 1512 and larger than the radius of the non-rough processing part 1514 . The regulating blade 560 is in contact with the developing roller 510 over the entire region from one axial end to the other end of the developing roller 510 , and controls the layer thickness of the toner carried on the developing roller 510 . Accordingly, it is possible to realize a developing device or the like in which the layer thickness of the toner carried on the developing roller 510 is appropriately limited.

That is, the uneven processing portion 1512 is provided at the central portion of the developing roller 510 in the axial direction, and the non-concave-convex processing portion 1514 is provided at both ends in the axial direction. The entire area from one end to the other end abuts on the developing roller 510, so if there is a large step between the uneven processed portion 1512 and the non-embossed processed portion 1514, the regulating blade 560 cannot properly abut on the developing roller 510. As a result, the above-mentioned function of regulating the blade 560 , that is, the function of regulating the layer thickness of the toner carried on the developing roller 510 cannot be properly performed.

In contrast, in the developing device of the present embodiment, since the intermediate portion 1516 is provided between the unevenly processed portion 1512 and the non-unevenly processed portion 1514 in the axial direction of the developing roller 510, the intermediate portion 1516 has a higher thickness than the unevenly processed portion 1512. The maximum radius is small and larger than the radius of the non-concave-convex processed portion 1514, so there is no large step between the concavo-convex processed portion 1512 and the non-convex-convex processed portion 1514, so that the limiting blade 560 and the developing roller 510 can properly abut against each other. catch. Therefore, the regulating blade 560 can more properly regulate the layer thickness of the toner carried on the developing roller 510 .

<<Other embodiments of the second embodiment>>

In the above-described embodiment, the radius of the intermediate portion 1516 is larger (radius r5) on the side of the roughened portion 1512 and smaller (radius r3) on the side of the non-roughened portion 1514, but the present invention is not limited thereto. For example, in FIG. 18 , the radius r3, radius r4, and radius r5 may also be the same (the relationship between radius r1 and radius r2 is: radius r1<radius r3=radius r4=radius r5<radius r2).

However, the above embodiment is more preferable in that the display plate 560 abuts against the developing roller 510 more appropriately, and thus the thickness of the layer of toner carried on the developing roller 510 is more appropriately restricted by the regulating blade 560 .

In addition, in the above-mentioned embodiment, the radius of the intermediate portion 1516 gradually decreases from the side of the concave-convex processed portion 1512 to the side of the non-concave-convex processed portion 1514 of the intermediate portion 1516 (radius r5>radius r4>radius r3), but it is not limited thereto. . For example, in FIG. 18 , the radius r3 and the radius r4 can also be the same (the relationship between the radius r1 and the radius r2 is: radius r1<radius r3=radius r4<radius r5<radius r2).

However, the above embodiment is more preferable in that the display plate 560 abuts against the developing roller 510 more appropriately, and thus the thickness of the layer of toner carried on the developing roller 510 is more appropriately restricted by the regulating blade 560 .

In addition, in the above-described embodiment, there is the end seal 527 for preventing toner leakage that is in contact with the non-convex-processed portion 1514 along the peripheral surface of the developing roller 510, and the surface of the concavo-convex processed portion 1512 is treated. Plating treatment is performed, but no plating treatment is performed on the surface of the middle part 1516, but it is not limited thereto. For example, plating treatment may be performed on both the surface of the uneven processing part 1512 and the surface of the intermediate part 1516 .

If the surface of the developing roller 510 is plated, since the rolling property of the toner is improved, the chargeability of the toner can be improved. However, if the plating treatment is performed not only on the surface of the concave-convex processed portion 1512 but also on the surface of the intermediate portion 1516, the toner tends to move more easily due to the improvement of the rollability. The non-corrugated portion 1514 where the end seal 527 from which the toner leaks contacts (in other words, needs to seal the toner) moves.

In the above embodiment, since only the former of the surface of the concave-convex processed part 1512 and the surface of the intermediate part 1516 is plated, and the latter is not plated, the chargeability of the toner can be improved, and the toner can be suppressed. The toner moves to the non-concave-convex portion 1514 to appropriately prevent toner leakage. From this point of view, the above-described embodiment is more preferable.

In addition, in the above-described embodiment, the grooves formed in the axial center portion of the developing roller 510 are formed in the middle portion 1516 between the axial end portions and the axial center portion in depth by roll forming. The groove 1518 is smaller than the groove 1518 , thereby realizing the middle portion 1516 having a radius smaller than the maximum radius of the concave-convex processing portion 1512 and larger than that of the non-concave-convex processing portion 1514 , but not limited thereto.

For example, the middle portion 1516 having a radius smaller than the maximum radius of the uneven portion 1512 and larger than the radius of the non-uneven portion 1514 may also be realized by cutting the non-uneven portion 1514 and the intermediate portion 1516. (At this time, the groove 1518 may not be formed in the intermediate portion 1516).

However, the above embodiment is more preferable in that the intermediate portion 1516 having a radius smaller than the maximum radius of the uneven portion 1512 and larger than the radius of the non-uneven portion 1514 can be easily realized.

[Third Embodiment]

<<Structural Example of the Developing Roller 510 of the Developing Device of the Third Embodiment>>

Here, a configuration example of the developing roller 510 of the developing device according to the third embodiment will be described with reference to FIGS. 19 to 22 . FIG. 19 is a schematic perspective view of the developing roller 510, showing the helical first groove 2518a and the second groove 2518b whose winding directions are different from each other. 20 is a schematic front view of the developing roller 510 showing the positional relationship between the groove-forming portion 2512 and the non-grooving-forming portion 2514 of the developing roller 510 . FIG. 21 is a schematic diagram of the cross-sectional shape of the groove 2518 . FIG. 22 is a schematic cross-sectional view along AA of FIG. 20 , showing the difference between the depth of the groove 2518 in the central portion 2512a and the depth of the groove 2518 in the two end portions 2512b. In addition, in FIGS. 19 to 22 , the scales of the grooves 1518 and the like are different from actual ones in order to make the figures easier to understand. In addition, FIG. 21 shows a cross section along the direction indicated by symbol X in FIG. 20 .

The developing roller 510 of the developing device according to the third embodiment carries the toner T and conveys it to a developing position facing the photoreceptor 20 . The developing roller 510 is a member made of aluminum alloy, iron alloy, or the like. As shown in FIG. 20, FIG. 22, etc., the developing roller 510 is mainly divided into two parts (groove forming part 2512, non-groove forming part 2514) according to the structure difference of its surface.

The groove forming portion 2512 is a portion located at the center in the axial direction of the developing roller 510 , and its surface is roughened in order to support the toner T properly. In the present embodiment, the above-mentioned roll forming process is used for the concavo-convex processing, and concave parts and convex parts are formed on the surface of the groove forming part 2512 by this roll forming process. That is, as shown in FIGS. 21, 22, etc., grooves 2518 are formed on the surface of the groove forming portion 2512 by roll forming, whereby the groove forming portion 2512 has grooves 2518 as recesses and protrusions as protrusions. The non-groove portion 2519 (both the groove 2518 and the non-groove portion 2519 function as a toner carrying portion for carrying toner).

As shown in FIGS. 19 and 20 , in this embodiment, as the grooves 2518 , spiral first grooves 2518 a and second grooves 2518 b whose winding directions are different from each other are provided. The acute angle formed by the length direction of the first groove 2518a and the axial direction and the acute angle formed by the length direction of the second groove 2518b and the axial direction are both about 45 degrees. In addition, the groove forming portion 2512 at the central portion 2512a in the axial direction of the developing roller 510 and the groove forming portion 2512 at the end portions 2512b (both ends) in the axial direction are slightly different regarding the groove 2518 and the like. .

As shown in FIG. 21, in the central portion 2512a, the depth of the groove 2518 is about 7 μm. In this embodiment, the toner T is granular (granular), and since the volume average particle diameter of the toner T is about 7 μm, the depth of the groove 2518 is related to the size of the volume average particle diameter of the toner T. Roughly equal. In the central portion 2512a, the width of the groove 2518 is about 80 μm, and the groove angle (angle indicated by symbol α in FIG. 21 ) is about 90 degrees. In addition, the surface of the central portion 2512a was subjected to electroless Ni-P plating.

On the other hand, as shown in FIG. 22, at the end portion 2512b, the depth of the groove 2518 is smaller than the depth of the groove 2518 formed on the central portion 2512a (in FIG. groove 2518 on the end portion 2512b, but actually there are more than three grooves 2518 on the end portion 2512b). In this embodiment, the depth of the groove 2518 formed on the end portion 2512b is about half of the depth of the groove 2518 formed on the central portion 2512a. In addition, unlike the central portion 2512a, the surface thereof is not subjected to electroless Ni-P plating.

The non-groove forming portion 2514 is a portion that is not subjected to the above-mentioned unevenness (roll forming) on its surface, and the spiral groove 2518 is not formed therein. The non-groove forming portion 2514 is located outside the groove forming portion 2512 in the axial direction of the developing roller 510, and has a smooth surface (the ten-point average roughness Rz of the surface is 1 μm or less). In addition, as with the aforementioned end portion 2512b, the surface of the non-groove forming portion 2514 is not subjected to electroless Ni—P plating.

In addition, as described above, in the developing roller 510 of the present embodiment, the depths of the grooves 2518 are different between the central portion 2512 a and the end portion 2512 b of the groove forming portion 2512 . When carrying out above-mentioned roll forming processing, can make the depth of groove 2518 different by changing the pressing force that mold is pressed to non-roll forming process developing roller (when wanting to make the depth of groove 2518 little, can reduce by pressure, when the depth of the groove 2518 is to be increased, the pressing force can be increased).

<<Effectiveness of the developer according to the third embodiment>>

As described above, the developing device according to this embodiment has the developing roller 510 for carrying toner and the end seal 527 . The developing roller 510 has a groove forming portion 2512 on which a spiral groove 2518 is formed. The depth of the groove 2518 is smaller than the depth of the groove 2518 formed on the axial central portion 2512a; and the non-groove forming portion 2514, which is located outside the groove forming portion 2512 in the axial direction, is not formed. There is the spiral groove 2518 . The end seal 527 is in contact with the non-groove forming portion 2514 along the peripheral surface of the developing roller 510 to prevent toner leakage. Accordingly, it is possible to realize a developing device and the like in which toner leakage is appropriately prevented.

That is, in the above-mentioned developing device, it is necessary to prevent the toner from leaking out from between the peripheral surface of the developing roller 510 and the casing 540 of the developing device, etc. The end seal 527 is in contact with the non-groove forming portion 2514 to prevent toner leakage.

However, merely providing the end seal 527 in the developing device may not be sufficient as a countermeasure against toner leakage, and further studies on countermeasures against toner leakage are required.

In this regard, in this embodiment, the groove 2518 formed on the end portion 2512b and the groove 2518 formed on the central portion 2512a are formed in the spiral groove 2518 formed on the surface of the groove forming portion 2512. The grooves 2518 are different to achieve the countermeasure against toner leakage. That is, in this example, unlike the conventional example (an example in which the helical groove 2518 does not change between the central portion 2512a and the end portion 2512b), since the groove 2518 formed on the end portion 2512b The depth is smaller than the depth of the groove 2518 formed on the central portion 2512a, so compared with the conventional example, it is located inside the groove 2518 formed on the end portion 2512b and moves along the groove 2518 toward the non-groove forming portion. The amount of toner moving in the direction of 2514 becomes smaller. Therefore, in this example, the amount of toner reaching the end seal 527 in contact with the non-groove forming portion 2514 becomes smaller compared with the conventional example, thereby appropriately preventing toner leakage.

<<Other measures to prevent toner leakage>>

In the above description, the following countermeasures for further preventing toner leakage have been described, that is, in the spiral groove 2518 formed on the surface of the groove forming part 2512, the groove formed on the end part 2512b The groove 2518 is different from the groove 2518 formed in the central portion 2512a, that is, the groove 2518 formed in the end portion 2512b has a smaller depth than the groove 2518 formed in the central portion 2512a. (this example). However, this example is only an example of preventing toner leakage by making the groove 2518 formed in the end portion 2512b different from the groove 2518 formed in the central portion 2512a, and other examples are also conceivable. In this item, other examples of countermeasures for preventing toner leakage by making the groove 2518 formed on the end portion 2512b different from the groove 2518 formed on the central portion 2512a (first modification and second modification) are shown. example).

<First modified example>

First, a first modification will be described using FIGS. 23 and 24 . FIG. 23 corresponds to FIG. 6 and is a schematic front view of the developing roller 510 of the first modification. Fig. 24 will be described in detail later.

As shown in FIG. 23, in the developing roller 510 of the first modified example, the acute angle formed by the longitudinal direction of the groove 2518 formed on the end portion 2512b and the axial direction of the developing roller 510 is larger than that formed in the central groove 2518. The acute angle formed by the longitudinal direction of the groove 2518 on the portion 2512a and the axial direction.

In more detail, in the developing roller 510 of the present example described above, there is no difference between the central portion 2512a and the end portion 2512b in terms of the acute angle formed by the longitudinal direction of the groove 2518 and the axial direction, which The size of the acute angle is about 45 degrees. In the developing roller 510 of the first modified example, the acute angle formed by the longitudinal direction of the groove 2518 formed on the central portion 2512a and the axial direction is about 45 degrees as in this example, and the groove 2518 formed on the end portion 2512b The acute angle formed by the longitudinal direction of the upper groove 2518 and the axial direction is about 60 degrees (>45 degrees).

In this way, by making the acute angle formed between the longitudinal direction of the groove 2518 formed in the end portion 2512b and the axial direction larger, toner leakage can be properly prevented. This is explained using FIG. 24 . 24 is an explanatory diagram for explaining the effectiveness of the first modification, showing the movement of toner near the boundary 2515 between the non-groove forming portion 2514 and the end portion 2512b (indicated by arrows in FIG. 24 ). movement of the toner). An example (comparative example) when the acute angle is small (45 degrees) is shown in the left diagram of FIG. 24 , and an example when the acute angle is large (60 degrees) is shown in the right diagram of FIG. 24 (that is, first modified example).

The toner in the groove 2518 formed in the end portion 2512b can move along the groove 2518 toward the non-groove forming portion 2514, but since the non-groove forming portion 2514 does not have the groove 2518, the As a result of moving along the groove 2518 , the toner within the groove 2518 that reaches the boundary 2515 between the non-groove forming portion 2514 and the end portion 2512 b overflows from the groove 2518 . Then, as shown in FIG. 24 , the toner overflowing from the groove 2518 is divided into the toner moving to the non-groove forming portion 2514 side over the wall 2515 a located at the boundary, and the toner bounced by the wall 2515 a. The toner that has moved back to the end portion 2512b side, when comparing the first modification example and the comparative example, the toner that has moved to the non-groove forming portion 2514 side in the first modification example Due to the difference in the acute angle, the amount of toner is smaller than the amount of toner moving toward the non-groove forming portion 2514 side in the comparative example (conversely, toward the end portion 2512b in the first modified example). The amount of toner moved to one side is larger than the amount of toner moved to the end portion 2512b side in the comparative example). Therefore, in the first modified example, the amount of toner reaching the end seal 527 in contact with the non-groove forming portion 2514 becomes smaller in comparison with the comparative example, thereby properly preventing toner leakage.

In addition, as described above, in the developing roller 510 of the first modified example, in the central portion 2512 a and the end portion 2512 b of the groove forming portion 2512 , the length direction of the groove 2518 forms an acute angle with the axial direction of the developing roller 510 . different sizes. The acute angle can be adjusted by making the die used when roll forming the central portion 2512a differ from the die used when roll forming the end portion 2512b (more specifically, the shape of the blade is different). different sizes.

In addition, as in the present example, in the first modified example, the first groove 2518a and the second groove 2518b are formed as the spiral groove 2518 in the groove forming portion 2512, and the winding directions are different from each other, But not limited to this. For example, in this example or the first modified example, only either one of the first groove 2518a or the second groove 2518b may be provided.

<Second modification>

Next, a second modified example will be described using FIG. 25 . FIG. 25 corresponds to FIG. 6 and is a schematic front view of a developing roller 510 according to a second modified example. In addition, in FIG. 25, the first directions described later are represented by symbols d1, d2, and the directions of the first directions d1, d2 along the axial direction of the developing roller 510 are represented by symbols dx1, dx2, and the directions of the first directions d1, d2 along the axial direction of the developing roller 510 are represented by symbols dy1, dy1, dy2 represents the direction of the first direction d1, d2 along the circumferential direction of the developing roller 510 .

As shown in FIG. 25, in the developing roller 510 of the second modified example, the first groove 2518a and the first groove 2518a, which are spiral grooves 2518 and whose winding directions are different from each other, are formed in the central portion 2512a. The second groove 2518b, and only one of the first groove 2518a and the second groove 2518b is formed at the end portion 2512b (in FIG. Among the second grooves 2518b, the grooves 2518 formed on the end portion 2512b are indicated by broken lines, and the grooves 2518 not formed on the end portion 2512b are indicated by dotted lines).

More specifically, when two directions are directed in opposite directions to each other along the length direction of the groove 2518 formed on the end portion 2512b, the direction of the direction along the circumferential direction of the developing roller 510 is aligned with the direction of the developing roller 510. The direction of rotation (in FIG. 25, the rotation direction is represented by the symbol r) is consistent with the first direction (in FIG. 25, the first direction of the first groove 2518a is represented by the symbol d1, and the symbol d2 To represent the first direction of the second groove 2518b), in the first groove 2518a and the second groove 2518b, the direction along the axial direction of the developing roller 510 of the first direction d1, d2 and the direction from the end portion 2512b toward the direction of the central portion 2512a (in FIG. 25, this direction is represented by the symbol X1), and from the end portion 2512b toward the direction of the non-groove forming portion 2514 (in FIG. 25, the direction is represented by the symbol X2 to indicate the direction), the latter consistent groove 2518 is provided on the end 2512b.

More specifically, at the end portion 2512b located on the left side in FIG. 25 , the first direction d1 of the first groove 2518a along the axial direction dx1 is consistent with the direction X1 from the end portion 2512b toward the central portion 2512a, and The first direction d2 of the second groove 2518b along the axial direction dx2 is consistent with the direction X2 from the end portion 2512b toward the non-groove forming portion 2514, therefore, the groove 2518 satisfying the above conditions is the second groove 2518b. Thus, only the second groove 2518b of the first groove 2518a and the second groove 2518b is formed on the end portion 2512b located on the left side in FIG. 25 .

On the other hand, at the end portion 2512b located on the right side in FIG. 25 , the first direction d1 of the first groove 2518a along the axial direction dx1 is consistent with the direction X2 from the end portion 2512b toward the non-groove forming portion 2514 , and the first direction d2 of the second groove 2518b along the axial direction dx2 is consistent with the direction X1 from the end portion 2512b to the central portion 2512a, therefore, the groove 2518 satisfying the above conditions is the first groove 2518a . Thus, only the first groove 2518a of the first groove 2518a and the second groove 2518b is formed on the end portion 2512b located on the left side in FIG. 25 .

When the groove 2518 is formed on the end portion 2512b as above, toner leakage can be properly prevented. That is, when a groove 2518 that does not satisfy the above conditions is formed on the end portion 2512b (in FIG. 25, the first groove 2518a on the left end portion 2512b in FIG. When the second groove 2518b) on the side end portion 2512b is formed, if the developing roller 510 rotates in the rotation direction r, the toner in the groove 2518 formed on the end portion 2512b will flow along the groove 2518 to the non- The groove forming part 2514 moves (at the end portion 2512b on the left side in FIG. 25, the moving direction of the toner is opposite to the first direction d1; 2 goes to d2 opposite).

In contrast, when a groove 2518 satisfying the above conditions is formed on the end portion 2512b (in FIG. 25, the second groove 2518b on the left end portion 2512b in FIG. When the first groove 2518a) on the right end 2512b is removed, if the developing roller 510 rotates in the rotation direction r, the toner in the groove 2518 formed on the end 2512b will move along the groove 2518. And move in the direction opposite to the non-groove forming portion 2514 (that is, the direction of the central portion 2512a) (the end portion 2512b on the left side in FIG. The end portion 2512b on the middle right side, the moving direction of the toner is opposite to the first direction d1), therefore, the amount of toner reaching the end seal 527 in contact with the non-groove forming portion 2514 becomes smaller, thereby appropriately Toner leakage is prevented.

In addition, as described above, in the developing roller 510 of the second modified example, the first groove 2518a and the second groove 2518b are formed in the central portion 2512a, and only the left end portion 2512b in FIG. 25 is formed. There is a second groove 2518b, and only the first groove 2518a is formed on the end portion 2512b on the right side in FIG. 25 . If the groove 2518 is formed by two dies on the central portion 2512a, and only one die is used to form the groove 2518 on the end portion 2512b on the left side in FIG. If the grooves 2518 are formed by another die, the developing roller 510 of the second modified example can be realized.

<<Other Embodiments of the Third Embodiment>>

In the above description, the surface of the central portion 2512a is plated and the surface of the end portion 2512b is not plated, but the present invention is not limited thereto. For example, both the surface of the center part 2512a and the surface of the end part 2512b may be plated.

If the surface of the developing roller 510 is plated, since the rolling property of the toner is improved, the chargeability of the toner can be improved. However, if the plating treatment is performed not only on the surface of the center portion 2512a but also on the surface of the end portion 2512b, the toner will more easily move toward the surface of the toner by the method for preventing toner leakage due to the improvement of the rolling property. The non-groove forming portion 2514 where the end seal 527 contacts (in other words, needs to seal the toner) moves.

In the above-described embodiment, since only the former of the surfaces of the center portion 2512a and the end portion 2512b is plated, and the latter is not plated, the chargeability of the toner can be improved, and the toner can be increased by suppressing the toner. The toner moves to the non-roughened portion 2514 to appropriately prevent toner leakage. From this point of view, the above-described embodiment is more preferable.

[Fourth embodiment]

In the above-described embodiments (including the second embodiment and the third embodiment), the end seals 527 are provided so as to abut against both end portions of the surface of the developing roller 510 where groove portions are not provided, but the present invention is not limited thereto. For example, as shown in FIGS. 26 and 27 , it may be provided so as to be in contact with the groove forming portion of the developing roller 510 where the groove 3518 is formed. FIG. 26 is an enlarged view of the vicinity of the end of the groove formation portion according to the fourth embodiment. FIG. 27 is a view showing a state where pile yarns are in contact with the groove forming portion of the developing roller according to the fourth embodiment.

In this case, the surface of the end seal 527 that is in contact with the groove forming portion is preferably made of woven fabric, not non-woven fabric.

In this embodiment, the end seal 527 is a component made of fabric, and the fabric may be a pile fabric. In addition, pile yarns 527a of fluoride fibers in a raised state are provided on the surface of a base fabric 527b included in the pile fabric, and the pile yarns 527a are in contact with the groove forming portion of the developing roller. In addition, the velvet yarn 527a is woven into the bottom line of the base fabric 527b, and its density arranged on the surface of the base fabric 527b is approximately uniform (that is, as shown in FIG. One end portion 527d is located on the opposite side to the front end portion 527c of the pile yarn 527a through the base fabric 527b). In addition, the pile fabric is pressed so that, as shown in FIG. 27 , the pile yarn 527a is not in an upright state with respect to the surface of the bottom portion 527b, and its front end portion 527c is inclined inwardly of the groove forming portion. In this embodiment, the pile yarn 527a is cut pile (cut hair) shape, but it is not limited to this. For example, the pile yarn 527a may also be in the shape of loop pile (loop). Moreover, in this embodiment, although the end seal 527 is a member which consists only of fabrics, it is not limited to this. The surface of the end seal 527 in contact with the groove forming portion of the developing roller 510 may be a fabric, and may be used in combination with the fabric according to the gap between the developing roller 510 and the housing 540 to adjust the thickness. An end seal 527 of a non-woven fabric or the like of the component.

Next, effectiveness of the fourth embodiment will be described.

When the end seal 527 made of nonwoven fabric comes into contact with the groove forming portion, since the developing roller 510 slides on the surface of the end seal 527 while pressing the end seal 527, the The unevenness of the groove forming portion rubs against the surface of the end seal 527 , so that the fibers on the surface are easily untied or detached. As a result, the end seal 527 may not properly prevent the toner T from leaking.

On the other hand, when a fabric is used on the surface of the end seal 527 that is in contact with the groove forming portion, since all the fibers in the fabric are woven, it is possible to prevent the fibers from coming off due to the friction, Thus, the end seal 527 can properly prevent the toner T from leaking.

In this embodiment, the fabric of the end seal 527 that is in contact with the groove forming portion of the developing roller 510 is a pile fabric, and the pile yarn 527a woven into the base fabric 527b included in the pile fabric is combined with the pile yarn 527a. contact with the trench forming portion. At this time, the pile yarn 527a can well follow the unevenness of the groove forming portion and contact the groove forming portion. In addition, also because the contact pressure with the groove forming portion is small, the end seal 527 can ensure sealing performance in a state where the driving torque of the developing roller 510 is less suppressed. Therefore, the end seal 527 can more properly prevent toner leakage.

In addition, the pile yarn 527a is in contact with both ends in the axial direction of the developing roller 510 of the groove forming portion, and the orientation of the pile yarn 527a (that is, the orientation of the front end portion 527c of the pile yarn 527a) is The axial direction faces inwardly. At this time, the pile yarn 527a can catch the toner T moving toward the end of the groove forming portion. This is because the toner T facing the end is opposed to the front end 527c of the pile yarn 527a, and the toner T is easily captured by the pile yarn 527a. On the other hand, since the toner T captured by the pile yarn 527a tends to move along the direction of the pile yarn 527a, the toner T returns toward the inner side. Thus, the end seal 527 can more properly prevent toner leakage.

[Structure of image forming system, etc.]

Next, an embodiment of an image forming system as an example of the present embodiment will be described with reference to the drawings.

FIG. 28 is an explanatory diagram showing the external configuration of the image forming system. Image forming system 700 includes computer 702 , display device 704 , printer 10 , input device 708 , and reading device 710 .

In this embodiment, the computer 702 is housed in a mini-tower enclosure, but is not limited thereto. The display device 704 generally uses a CRT (Cathode Ray Tube: cathode ray tube), a plasma display, or a liquid crystal display device, etc., but is not limited thereto. As the printer 10, the printers described above are used. In this embodiment, the input device 708 uses a keyboard 708A and a mouse 708B, but it is not limited thereto. In this embodiment, the reading device 710 uses a floppy disk drive device 710A and a CD-ROM drive device 710B, but it is not limited to this, for example, it can also be a magneto-optical (MO: Magneto Optical) disk drive device or a DVD (Digital Versatile Disk) etc. other devices.

FIG. 29 is a block diagram showing the configuration of the image forming system shown in FIG. 28 . An internal memory 802 such as a RAM and an external memory such as a hard disk drive unit 804 are also provided in a casing housing the computer 702 .

In the above description, an example in which the printer 10 is connected to the computer 702 , the display device 704 , the input device 708 , and the reading device 710 to form an image forming system has been described, but the present invention is not limited thereto. For example, the image forming system may be composed of the computer 702 and the printer 10 , and the image forming system may not include some of the display device 704 , the input device 708 , and the reading device 710 .

For example, the printer may have a part of the respective functions or structures of the computer 702 , the display device 704 , the input device 708 , and the reading device 710 . As an example, the printer 10 may have an image processing unit for performing image processing, a display unit for performing various displays, and a recording medium loading and unloading unit for loading and unloading a recording medium on which data is recorded. Image data captured by the camera.

The image forming system realized as described above is superior to conventional systems as a whole.

Claims (3)

1. A developing device, comprising: an accommodating portion accommodating toner particles for developing a latent image carried on the image carrier; and a toner particle carrying roller having, on a surface for carrying the toner particles, spiral grooves inclined with respect to the axial direction and the circumferential direction and formed at equal intervals in the axial direction, the latent image has a dot-like latent image formed in areas divided into grids, The lattice may be formed at various pitches in the axial direction, The pitch of the groove portion in the axial direction is smaller than the longest pitch among the various pitches of the grid. 2. The developing device according to claim 1, wherein the depth of the groove portion is not more than twice the volume average particle diameter of the toner particles. 3. An image forming apparatus comprising the developing device according to claim 1 or 2.

Images