CN101515145B - Development roller, development device, image forming apparatus, and method of manufacturing development roller - Google Patents

Abstract

The invention provided a development roller development device, image forming apparatus, and method of manufacturing development roller can realize well development for a long time by inhibiting reduce of the depth of the convex-concave part after forming images for a long time. The development roller at least comprises a base unit (25a) a base recess (29a',29b') and a base projection (30') that are formed in a predetermined area of a circumference surface of the base unit; and a surface layer (25b) formed on the circumference surface of the base unit (25a) and having a recess (29a,29b) and a projection (30). The surface hardness of the projection (30) is larger that the surface hardness of the recess (29a,29b).

Description

Developing roller, developing device, image forming device, and manufacturing method of developing roller

technical field

The present invention relates to the technical field of a developing roller having concavo-convex portions on its outer peripheral surface to convey toner to a latent image carrier, a developing device having the developing roller, an image forming device having the developing device, and a manufacturing method of the developing roller.

Background technique

Conventionally, in a developing device for developing an electrostatic latent image with toner of a non-magnetic component, the toner is charged by triboelectric charging on a developing roller. As such a developing roller, a developing roller having concavo-convex portions on the outer peripheral surface and a flat or substantially flat surface of the convex portions is known (for example, refer to Patent Document 1). In this concave-convex portion, the toner is effectively frictionally charged on the developing roller. As shown in FIG. 10(a), the developing roller a is composed of a base member b and a surface layer c covering the surface of the base member b by plating.

[Patent Document 1] JP-A-2007-121948.

Generally, a not-shown toner supply roller and a toner restricting member are in contact with the developing roller a. In addition, as one of the external additives covering the toner base particles, silica with high hardness is used. On the other hand, on the outer peripheral surface of the base b, a plurality of base concave-convex portions composed of the base concave portion d and the base convex portion e are formed. In addition, in the surface layer c, corresponding to these base recesses d and base protrusions e, base recesses and protrusions composed of recesses f and protrusions g are also formed.

However, by image formation, the surface layer c is abraded due to the toner supply roller, the toner restricting member, or the toner particles. On the other hand, in recent years, due to demands for higher image quality and reduction in the amount of toner used, the particle size of toner has become smaller. If image formation is carried out over a long period of time using this toner with a small particle size, as shown in FIG. Almost flat. If the wear state or wear amount is different between the concave portion f and the convex portion g, the depth of the concave-convex portion decreases due to long-time image formation. Therefore, the amount of toner conveyed by the developing roller decreases, making it difficult to maintain the image density, and it is difficult to perform good development over a long period of time.

Contents of the invention

The present invention was made in view of such circumstances, and an object of the present invention is a developing roller, a developing device, and an image forming device capable of performing good development over a long period of time by suppressing the decrease in the depth of the unevenness as much as possible even if an image is formed over a long period of time. and a method of manufacturing a developing roller.

As a first solution to the above-mentioned problems, according to the developing roller, the developing device, and the manufacturing method of the developing roller of the present invention, in the uneven portion of the developing roller, the surface hardness of the convex portion is greater than that of the concave portion. Therefore, during image formation over a long period of time, abrasion of the surface layer of the convex portion, which is relatively easy to wear, can be suppressed. This makes it possible to further reduce the difference in wear between the surface layer of the concave portion and the surface layer of the convex portion, which are relatively less worn, compared with the conventional developing roller. Even if image formation is performed over a long period of time, changes in the depth of the uneven portion of the developing roller can be suppressed. As a result, the amount of toner conveyed by the developing roller hardly changes, and the image density can be kept almost constant over a long period of time. Therefore, favorable image development can be performed over a long period of time.

In addition, by actively scraping the surface layer by reducing the surface hardness of the concave portion of the developing roller, it is possible to prevent deteriorated toner from stagnating in the concave portion of the toner supply roller with poor repositionability and causing filming. Moreover, since the distance from the toner limiting blade is long in the concave portion, the chargeability of the toner often deteriorates. However, by maintaining the concave portion in an amorphous state, the decrease in the chargeability of the toner can be suppressed. Accordingly, toner coating, toner scattering, and the like can be suppressed, and favorable developing properties can be obtained.

Moreover, in the toner conveying method in which the toner is not conveyed to the surface of the convex portion by the toner restricting member, the functions of the concave portion, such as ensuring the chargeability of the toner on the surface of the concave portion, and the ensuring of the wear resistance of the surface of the convex portion can be combined. The function of the convex portion (maintenance of the depth of the concave-convex portion) is separated to realize two functions.

In addition, by crystallizing the tops of the convex portions, toner chargeability at the tops can be reduced. Since the chargeability of the toner is not so good, excessive charging (charging) caused by sliding friction between the toner restricting blade and the convex portion of the developing roller can be prevented instead, and the developing experience can be improved. In addition, use toner with a smaller particle size than the depth of the unevenness of the developing roller, and contact the front end of the toner limiting blade with the developing roller to transport the toner to the concave portion of the developing roller, and in the method of not conveying to the convex portion , can more effectively suppress the toner to the convex portion, and can also prevent the toner from filming or excessive charging on the convex flat surface.

And, constitute the concavo-convex part of surface layer with the same material, by making the crystallization degree of concave part and convex part different (for example, make the crystallization degree of convex part higher than the crystallization degree of concave part), the surface of convex part and concave part can be controlled. hardness and resistance. At this time, each surface layer of the convex portion and the concave portion is not completely crystallized. Accordingly, the surface composition of the developing roller can be easily created. If the hardness of the convex portion is increased and the abrasion thereof is excessively reduced, filming of toner welding occurs, but by controlling the degree of crystallization, the occurrence of this filming can be suppressed.

Furthermore, by locally heating the surface layer of the convex portion, crystallization of the base material is hardly affected. Therefore, it is possible to prevent warping or bending of the base member caused by stress relief of the base member or a change in the degree of crystallization.

Moreover, by setting the range where the crystallization of the convex portion proceeds from the upper surface of the convex portion within the average particle diameter of the toner used, the toner transported to the concave portion where the chargeability is likely to decrease can be compared with the amorphous concave portion. touch. Therefore, it is possible to prevent the chargeability of the toner from being lowered. That is, by making the toner chargeability of the concave portion higher than that of the convex portion, the toner can be charged more efficiently.

Furthermore, by forming a surface layer on the base by performing electroless plating before forming the concave-convex portion on the base, even if a relatively difficult-to-process material is used for the base, the surface layer based on this plating can also improve the shape of the concave-convex portion. stability. According to this, the smoothness of the surface of the concave-convex portion can be improved, the rotatability of the toner particles can be improved, and the filming of the toner on the concave-convex portion can be suppressed. Therefore, the toner transportability and toner chargeability can be maintained more favorably over a long period of time.

On the other hand, according to the developing device including the developing roller of the present invention, the electrostatic latent image on the latent image carrier can be developed satisfactorily over a long period of time. Furthermore, an image forming apparatus including the developing device can form stable and high-quality images over a long period of time.

As a second solution to solve the above-mentioned problems, according to the developing roller, the developing device, and the manufacturing method of the developing roller of the present invention, when forming a surface layer of one layer on the base, the surface hardness of the base is set to Higher surface hardness than the surface layer. In addition, when the base material forms a multilayer surface layer, the surface hardness of the surface layer adjacent to the inner side of the outermost surface layer is set to be higher than the surface hardness of the outermost surface layer. Therefore, by image formation, the surface layer of the substrate flat portion of the substrate convex portion or the outermost surface layer of the substrate flat portion is abraded due to the toner restricting blade, toner supply roller, or toner external additive, if these substrates If the surface layer inside the flat portion or the outermost surface layer is exposed, the abrasion rate of the convex portion of the developing roller decreases. Accordingly, the durability of the developing roller can be improved.

In addition, if the surface layer or the outermost surface layer of the base flat portion is reduced, the depth of the uneven portion of the developing roller will change somewhat, but the abrasion of the exposed base flat portion or the inner surface layer of the outermost surface layer can be suppressed. . Therefore, as a whole, changes in the depth of the uneven portion of the developing roller can be suppressed over a long period of time, and the depth of the uneven portion can be maintained favorably over a long period of time. As a result, the amount of toner conveyed by the developing roller hardly changes, and the image density can be maintained almost constant over a long period of time. Therefore, favorable image development can be performed over a long period of time.

In addition, although the chargeability of the toner is lowered due to the exposed base flat portion of the convex portion or the surface layer inside the outermost surface layer, the toner particles are sandwiched between the developing roller and the toner limiting blade, The frictional force is greater than that of the recessed portion, so that this portion can suppress a decrease in the chargeability of the toner. Accordingly, toner coating, toner scattering, and the like can be suppressed, and favorable developing properties can be obtained.

Moreover, in the toner conveying method in which the toner is not conveyed to the surface of the convex portion by the toner limiting blade, the function of the concave portion such as ensuring the chargeability of the toner on the surface of the concave portion and the abrasion resistance of the surface of the convex portion can be combined. The function of the convex portion such as securing (maintenance of the depth of the concave-convex portion) is separated, and two functions are realized.

Moreover, by setting the thickness of the surface layer of one layer or the thickness of the outermost surface layer to be within the average particle diameter (D50 particle diameter) of the toner used, the toner conveyed to the concave portion where the chargeability is likely to decrease can be separated from the toner. The concave portions of the amorphous metal are in contact. Therefore, it is possible to prevent the chargeability of the toner from being lowered.

In addition, the surface layer of one layer or the outermost surface layer of multiple surface layers is removed by grinding with a grinder or grinding with a grinder, even if the base convex portion of the base is used from the beginning. Alternatively, the developing roller in a state where the inner surface layer of the outermost surface layer of the flat portion of the base member is exposed can obtain the same effect as described above.

On the other hand, according to the developing device including the developing roller of the present invention, the electrostatic latent image on the latent image carrier can be developed satisfactorily over a long period of time. Furthermore, an image forming apparatus including the developing device can form stable and high-quality images over a long period of time.

Description of drawings

FIG. 1 is a diagram schematically showing an example of an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a cross-sectional view schematically showing the developing device shown in FIG. 1 .

Fig. 3 (a) is a diagram schematically showing a developing roller, a toner supply roller and a toner limiting member, (b) is a partial sectional view along line IIIB-IIIB of (a), and (c) shows only (b) ) partial cross-sectional view of the base.

Fig. 4 is a partial enlarged sectional view of Fig. 3(b) of the developing roller.

5( a ) is a diagram showing the dimensions of the uneven portion of the developing roller, and ( b ) is a diagram illustrating the wear process of the developing roller when the toner particle diameter is larger than the depth of the uneven portion of the developing roller.

6( a ) is a diagram illustrating the behavior of toner particles on the developing roller when the toner particle diameter is smaller than the depth of the uneven portion of the developing roller, and ( b ) is a diagram showing the wear state of the developing roller in ( a ).

7( a ) to ( c ) are diagrams illustrating an example of a method of manufacturing the developing roller shown in FIGS. 3 and 4 .

8( a ) to ( c ) are diagrams illustrating other examples of the manufacturing method of the developing roller shown in FIGS. 3 and 4 .

Fig. 9(a) is a graph showing the results of a toner rubbing test, and (b) and (c) are graphs showing the results of a surface potential test.

10( a ) is a partial cross-sectional view of a concave-convex portion of a conventional developing roller, and FIG. 10( b ) is a partial cross-sectional view illustrating wear of the convex portion of (a).

Fig. 11(a) is a diagram schematically showing a developing roller, a toner supply roller and a toner restricting member, (b) is a partial sectional view along line IIIB-IIIB of (a), (c) is a view showing (b) (d) is a partial cross-sectional view showing only the base member of (b).

Fig. 12 is a partially enlarged sectional view of Fig. 11(b) of the developing roller.

13( a ) is a diagram showing the dimensions of the uneven portion of the developing roller, and ( b ) is a diagram illustrating the wear process of the developing roller when the toner particle diameter is larger than the depth of the uneven portion of the developing roller.

14( a ) to ( c ) are diagrams illustrating an example of a method of manufacturing the developing roller shown in FIGS. 11 and 12 .

15( a ) to ( b ) are diagrams illustrating other examples of the manufacturing method of the developing roller shown in FIGS. 11 and 12 .

Detailed ways

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing an example of an embodiment of an image forming apparatus of the present invention.

Inside the apparatus main body 2 is provided a photoreceptor 3 which is a latent image carrier and is provided so as to be rotatable in a clockwise rotation direction α in FIG. 1 . Near the outer periphery of the photoreceptor 3, a charging device 4 is provided. Further, near the outer periphery of the photoreceptor 3 , a developing device, namely a rotary developing unit 5 , a primary copying device 6 , and a cleaning device 7 are arranged in order from the charging device 4 toward the rotation direction α of the photoreceptor 3 . The rotary developing unit 5 has a developing device 5Y for yellow, a developing device 5M for magenta, a developing device 5C for cyan, and a developing device 5K for black. Each of the developing devices 5Y, 5M, 5C, and 5K is detachably supported by a rotary wheel 5 a that is rotatable in a rotation direction β (rotating counterclockwise in FIG. 1 ) around a central axis. Furthermore, an exposure device 8 is disposed below the charging device 4 and the cleaning device 7 .

Furthermore, the image forming apparatus 1 has an endless belt-shaped intermediate transfer tape 9 which is an intermediate transfer medium. The intermediate transfer belt 9 is hung on a belt drive roller 10 and a driven roller 11 . A rotational driving force of an unillustrated motor is transmitted to the belt drive roller 10 . Then, the intermediate transfer tape 9 is rotated in the rotation direction γ (counterclockwise in FIG. 1 ) while being pressed against the device main body 2 by the primary transfer device 6 by the tape drive roller 10 .

On the belt drive roller 10 side of the intermediate transfer belt 9, a secondary transfer device 12 is provided. In addition, below the exposure device 8, there is provided a copying material cassette 13 for accommodating a sheet-like copying material (not shown, corresponding to the copying medium of the present invention) such as copying paper. Further, a pick-up roller 15 and a pair of gate rollers 16 are provided in the vicinity of the secondary copying device 12 on the copying material transport path 14 from the copying material cassette 13 to the secondary copying device 12 .

A fixing device 17 is provided above the secondary copying device 12 . The fixing device 17 has a heating roller 18 and a pressure roller 19 in pressure contact with the heating roller. Also, a row of reproduction material trays 20 is provided on the upper portion of the apparatus main body 2 . Furthermore, between the fixing device 17 and the copy material tray 20, a pair of copy material rolls 21 is provided.

In the image forming apparatus 1 of this example configured in this way, for example, a yellow electrostatic latent image is first formed on the photoreceptor 3 uniformly charged by the charging device 4 by, for example, laser light L from the exposure device 8 . The yellow electrostatic latent image on the photoreceptor 3 is developed by the yellow toner of the yellow developing device 5Y positioned at the illustrated developing position by the rotation of the rotary wheel 5 a. Thus, a yellow toner image is formed on the photoreceptor 3 . The yellow toner image is transferred onto the intermediate transfer belt 9 by the primary transfer device 6 . After copying, the toner remaining on the photoreceptor 3 is swept off by a cleaning blade or the like of the cleaning device 7 and recovered.

Next, a magenta electrostatic latent image is formed by the exposure device 8 on the photoreceptor 3 recharged by the charging device 4 in the same manner as described above. This magenta electrostatic latent image is developed with the magenta toner of the magenta developing device 5M positioned at the developing position. The magenta toner image on the photoreceptor 3 passes through the primary transfer device 6 and is transferred onto the intermediate transfer belt 9 so as to overlap the yellow toner image. After copying, the toner remaining on the photoreceptor 3 is recovered by the cleaning device 7 . Thereafter, similarly, toner images of cyan and black are sequentially formed on the photoreceptor 3 , and these toner images are sequentially copied onto the intermediate transfer belt 9 while overlapping the colors of the toner images copied earlier. In this way, a colored toner image is formed on the intermediate transfer belt 9 . Similarly, each toner remaining on the photoreceptor 3 is recovered by the cleaning device 7 after copying.

The colored toner image copied on the intermediate transfer belt 9 is copied by the secondary copying device 12 onto the copy material conveyed from the copy material cassette 13 through the copy material transport path 14 . At this time, the transfer material passes through the pair of gate rollers 16 and is transported to the secondary transfer device 12 at the same time as the colored toner image on the intermediate transfer belt 9 .

The toner image fixed on the reproduction material is heated and pressure-fixed by the heating roller 18 and the pressure roller 19 of the fixing device 12 . The reproduction material thus formed with an image is conveyed through the reproduction material conveyance path 14, discharged by the row reproduction material roller pair 21 to the row reproduction material tray 20, and accommodated.

Next, the configuration of the characteristic parts of the image forming apparatus 1 of this example will be described.

The developing devices 5Y, 5M, 5C, and 5K of the respective colors in the image forming apparatus 1 of this example have completely the same configuration. Therefore, in the following description of the developing devices 5Y, 5M, 5C, and 5K, symbols Y, M, C, and K for each color will be omitted for description. At this time, in order to distinguish it from the rotary developing unit 5, a symbol 5' is assigned to the developing device.

2 is a cross-sectional view along a direction perpendicular to the longitudinal direction of the developing device according to the embodiment of this example. The developing device 5' of this example is formed in a long container shape. As shown in FIG. 2, this developing device 5' is the same as the developing device described in Patent Document 1, and has a toner storage unit 23, a toner supply roller 24, a developing roller 25, and a toner roller on a long frame 22. The member 26 is defined. The toner storage portion 23, toner supply roller 24, developing roller 25, and toner restricting member 26 extend in the longitudinal direction of the developing device 5' (direction perpendicular to the paper surface in FIG. 2).

The toner storage portion 23 is divided into two first and second toner storage portions 23 a and 23 b by a partition wall 27 . At this time, the toner storage portion 23 is formed as a communication portion 23c in FIG. 2 in which upper portions of the first and second toner storage portions 23a, 23b communicate with each other. In this state, the movement of the toner 28 between the first and second toner storage portions 23 a , 23 b is suppressed by the partition wall 27 . If the rotary wheel 5a of the rotary developing unit 5 is rotated so that the developing device 5' is in a state upside down from the state shown in FIG. The powder 28 moves to the communicating portion 23c side. If the rotary wheel 5a is further rotated to make the developing device 5' into the state shown in Fig. 2, the toner 28 is moved to the first and second toner storage parts 23a, 23b sides again. Accordingly, part of the toner 28 previously stored in the first toner storage portion 23a moves into the second toner storage portion 23b, and part of the toner 28 previously stored in the second toner storage portion 23b Moving into the first toner storage portion 23a, the toner 28 in the toner storage portion 23 is mixed and stirred. The toner 28 is a non-magnetic component toner in which the toner base particles are coated with external additives. At this time, in the present invention, at least silica is used as an external additive.

In the lower portion in FIG. 2 inside the first toner storage portion 23a, the toner supply roller 24 is provided so as to be rotatable clockwise in FIG. 2 . Further, outside the frame 22, a developing roller 25 is provided so as to be rotatable counterclockwise in FIG. 2 . Furthermore, the developing roller 25 is provided close to (non-contacting) the photoreceptor 3 . In addition, the toner supply roller 24 is in contact with the toner supply roller 24 through the opening 22a of the frame 22 with a predetermined contact pressure. Also, a toner restricting member 26 is provided on the frame 22 . The toner restricting member 26 abuts on the developing roller 25 at a position downstream of a nip portion (abutting portion) of the developing roller 25 and the toner supply roller 24 in the rotational direction of the developing roller 25 . Accordingly, the toner restricting member 26 regulates the layer thickness of the toner 28 supplied from the toner supply roller 24 to the developing roller 25 . Therefore, the toner 28 confined by the toner regulating member 26 is conveyed toward the photoreceptor 3 by the developing roller 25 . Then, the electrostatic latent image on the photoreceptor 3 is developed by the toner 28 conveyed by the developing roller 25 in a non-contact manner, and toner images of the respective colors are formed on the photoreceptor 3 .

Example 1

As shown in FIG. 3( a ), on the outer peripheral surface of the developing roller 25 , similarly to the developing roller described in Patent Document 1, a mesh-shaped concave-convex pattern is formed. In the developing roller 25 of this example, grooves 29 are formed over the entire periphery at predetermined positions in the axial direction on the outer peripheral surface as the concave-convex pattern. At this time, the groove 29 is formed in a helical shape successively inclined at a predetermined angle (in the illustrated example, 45°, but not limited thereto) with respect to the axial direction of the developing roller 25 and has a predetermined number of regularities. One slanted groove 29a and a predetermined number of second slanted grooves 29b are formed successively in a helical shape inclined oppositely to the inclination of the first slanted grooves 29a. These first and second inclined grooves 29a, 29b are formed at intervals p at a prescribed pitch in their inclined direction and at a prescribed width W in the axial direction. In addition, each inclination angle and each pitch of the first and second inclined grooves 29a, 29b can be different from each other.

As shown in FIG. 3(b), the developing roller 25 is composed of a base member 25a and a surface layer 25b formed on the outer peripheral surface of the base member 25a. The base member 25a is made of a sleeve made of a metal material such as aluminum such as 5056 aluminum alloy or 6063 aluminum alloy or iron such as STKM. In addition, the surface layer 25b is constituted by a plating layer such as nickel plating or chromium plating performed on the base member 25a.

As shown in Figure 3 (c), on the outer peripheral surface of the base member 25a of the developing roller 25, the first and second slopes for forming the first and second slope grooves 29a, 29b are formed by rolling forming process respectively. Base grooves 29a', 29b'. The processing methods of the first and second inclined base grooves 29a', 29b' on the base can be conventionally known. Therefore, description of this processing method is omitted. Then, a predetermined number of island-shaped base protrusions 30' surrounded by the first and second inclined base grooves 29a', 29b' are formed on the outer peripheral surface of the base 25a. In addition, in the present invention, the recessed part of the base refers to the side closer to the base 25a than 1/2 of the depth of the first and second inclined base grooves 29a', 29b', and the convex part of the base 30' refers to the 1/2 of the depth of the first and second inclined base grooves 29a', 29b' protrudes outward from the base 25a.

As shown in FIG. 3(c) and FIG. 4, the top of the base convex portion 30' is formed on the base flat portion 30a'. The shape of the base flat part 30a' of each base protrusion 30' is such that when the inclination angle of the first and second inclined base grooves 29a', 29b' is 45 degrees and their pitch p is set to be When they are the same, they form a square, and when the inclination angles of the first and second inclined base grooves 29a', 29b' are other than 45 degrees, and their pitch p is set to be the same as each other, they form a rhombus. In addition, the shape of the base flat part 30a' of each base protrusion 30' is such that when the inclination angle of the first and second inclined base grooves 29a', 29b' is 45 degrees, and their pitch p is set When the first and second inclined base grooves 29a', 29b' are different from each other, they form a rectangle. When the inclination angles of the first and second inclined base grooves 29a', 29b' are other than 45 degrees, and their pitches p are set differently, they form a parallelogram. In addition, regardless of the quadrangular shape of the base flat portion 30a', the base flat portion 30a' side of the base convex portion 30' inclines its surrounding side walls to form a truncated quadrangular pyramid.

The portions of the base recesses constituting the first and second inclined base grooves 29a', 29b' are respectively formed in curved recesses of sinusoidal concave surfaces along their inclination directions. Furthermore, the surrounding side walls of the truncated pyramid shape of the base convex portion 30 ′ are formed continuously with the surrounding side walls of the sinusoidal curved concave portion of the base concave portion. In this case, the point where the surrounding side walls of the truncated pyramid shape of the base convex portion 30 ′ and the sinusoidal side wall of the base concave portion connect is 1/2 of the depth of the concavo-convex portion.

By performing electroless electroplating, such as nickel plating, on the outer peripheral surface of the base 25a forming the first and second inclined base grooves 29a', 29b' and the base flat portion 30a' of the base protrusion 30', A surface layer 25b is formed on the surface of the base member 25a. The first and second inclined grooves 29a, 29b are formed on the surface layer 25b in the same shape as the base recesses and base protrusions 30' of the first and second inclined base grooves 29a', 29b', respectively. Convex part 30.

The convex portion 30 forms a quadrangular flat top 30a. In addition, in the state where the surface layer 25b is formed on the base member 25a, the top 30a sides of the first and second inclined grooves 29a, 29b incline their surrounding side walls to form a truncated quadrangular pyramid shape. Furthermore, the side walls around the truncated pyramid shape are formed continuously with the side walls around the sinusoidal wave shape on the concave side of the first and second inclined grooves 29a, 29b.

Furthermore, on the developing roller 25 of this example, a high hardness portion 30a" (shown in FIG. 4 ) in which the surface hardness of the surface layer 25b of the top 30a of the convex portion 30 is greater than that of other parts is formed. At this time, the The range of the convex portion 30 (the depth t from the top surface of the convex portion 30 ) of the high hardness portion 30 a ″ is set within the average particle diameter of the toner to be used. In addition, the toner chargeability of the surface layer 25b other than the high hardness portion 30a″ including the concave portion of the first and second inclined grooves 29a, 29b is higher than that of the high hardness portion 30a″.

On the other hand, the inventors of the present invention, as shown in FIG. 10( b ), have relatively large wear of the top h of the convex portion g of the developing roller a to be flat, and the first and second inclined grooves The fact that the surface layer c of the concave portion forming portion f hardly wears away was investigated while further performing a durability test. In addition, the shape of the abrasion was measured with a laser microscope Keyence VK-9500 for three-dimensional measurement. The image forming apparatus used in the experiment was a printer of LP9000C manufactured by SEIKO EPSON. Then, instead of the developing roller used in this printer, the following developing roller 25 was used. At this time, in order to make the developing roller 25 usable, a printer of LP9000C manufactured by Seiko EPSON Co., Ltd. was remodeled. The image forming conditions of the durability test are the standard image forming conditions of the LP9000C printer.

The STKM material was used for the base material 25a of the developing roller 25, and the surface finishing of the base material 25a was performed by centerless processing before processing the uneven|corrugated part to the base material 25a. Next, by roll forming, the first and second inclined base grooves 29a', 29b' are formed. Next, as the surface layer 25b, a plating layer having a thickness of 3 μm was formed on the surface of the base member by electroless nickel-phosphorus (Ni—P) plating. At this time, as shown in FIG. 5(a), the unevenness of the developing roller 25 has a depth of unevenness (height from the bottom of the grooves 29a, 29b to the upper surface of the convex portion 30) of 6 μm and a pitch of unevenness of 100 μm. The width of the convex portion 30 on the 1/2 line is 60 μm, and the width of the concave portion (grooves 29 a, 29 b ) on the 1/2 line of the unevenness depth is 40 μm.

In addition, the toner supply roller 24 is formed of a foamed urethane roller, and is provided with an incision amount of 1.5 mm relative to the developing roller 25 . Furthermore, the toner restricting member 26 is composed of a blade made of urethane rubber, and is provided with a contact pressure of 40 g/cm against the developing roller 25 .

Also, the toners used are two types of toners. One of the toners is to add CCA, WAX, and pigments in an appropriate amount to the polyester particles made by the pulverization method to form toner master particles, and to add 20nm small particle diameter silicon dioxide to the toner master particles. Medium particle size silica of 40nm, large particle size silica of 100nm, and titanium dioxide of 30nm have an average particle size D50 of 4.5 μm, which is a small particle size toner smaller than the depth of unevenness of 6 μm. Another toner is to add appropriate amount of WAX and pigments to the styrene propylene particles produced by the polymerization method to form toner master particles, and add 20nm small particle size silica and 40nm medium to the toner master particles. Silica with a particle size of 100 nm, silicon dioxide with a large particle size of 100 nm, and titanium dioxide with a particle size of 30 nm. The average particle size D50 is a toner with a small particle size of 4.5 μm similar to the above-mentioned toner.

Then, under the standard image forming conditions of LP9000C, a durable image forming experiment was carried out on A4 plain paper using a monochromatic character pattern with an image occupancy rate of 5%. As a result of this experiment, the top 30a of the surface layer 25b of the convex portion 30 having the initial profile indicated by the solid line in FIG. The tendency to shape contours.

The reason for this is considered to be as follows. In FIG. 6(a), along with the rotation of the developing roller 25, the toner particles located on the flat surface 30a of the convex portion 30 are respectively Move into the first and second inclined grooves 29a, 29b. At this time, in FIG. 6(a), the toner particles located at the top 30a of the convex portion 30 move into the first and second inclined grooves 29a, 29b, respectively, as the developing roller 25 rotates. At this time, since the average particle size (D50 particle size) of the toner particles is smaller than the depth of the concave-convex portion, the particles of the toner 28 moving into the first and second inclined grooves 29a, 29b form multiple layers. Further, the toner particles located in the first and second inclined grooves 29a, 29b move to the tops 30a of the protrusions 30 as the developing roller 25 rotates. At this time, the position of the toner particles of the uppermost layer is almost at the same height position as the top 30a of the convex portion 30, so among the particles of the toner 28 located in the first and second inclined grooves 29a, 29b, the uppermost layer is mainly The toner particles in the upper layer move roughly laterally, and the toner particles in the lower layer hardly move. Due to the lateral movement of the toner particles in the uppermost layer, the surface of the surface layer 25b is gradually worn down to a flat shape over a long period of time due to the hard external additives on the surface of the toner particles.

6( a ) and ( b ) are cross-sectional views along the oblique direction of the first and second oblique grooves 29 a and 29 b , as in FIG. 3( b ). Therefore, the partial cross sections of these developing rollers 25 are different from the rotational directions of the developing rollers 25 . Therefore, the toner particles located in the first inclined groove 29a move to the top 30a of the protrusion 30, and then, the toner on the top 30a also moves to the first and second inclined grooves 29a, 29a, and 29a adjacent to the top 30a. Either of 29b. In addition, the toner particles located in the second inclined groove 29a move to the top 30a of the convex portion 30, and then, the toner on the top 30a also moves to the first and second inclined grooves 29a, 29a, and 29a adjacent to the top 30a. Either of 29b. The same applies to the description of other examples below.

An example of a method of manufacturing the developing roller 25 configured in this way will be described.

As shown in Fig. 7(a), on the base member 25a, first and second inclined base member grooves 29a', 29b' are formed by roll forming. Next, as shown in FIG. 7(b), an amorphous surface layer 25b is formed by electroless plating on the surface of the base 25a where the first and second inclined base grooves 29a', 29b' are formed. Accordingly, the first and second inclined grooves 29a, 29b are formed corresponding to the first and second inclined base grooves 29a', 29b'. At this time, the protrusion 30 is on the side closer to the top 30a than 1/2 of the depth of the first and second inclined grooves 29a, 29b, and is closer to the top 30a than 1/2 of the depth of the first and second inclined grooves 29a, 29b. One side of the base member 25a (the side opposite to the top portion 30a) is a concave portion. At this time, the hardness of the surface layer 25b is set higher than the hardness of the base member 25a.

Next, as shown in FIG. 7(c), the surface layer 25b of the top portion 30a of the protrusion 30 is crystallized by ion beams, local heating, or the like. At this time, the depth t of the surface crystallized portion (high hardness portion 30a″) of the surface layer 25b from the upper surface of the top portion 30a is defined as the average particle diameter of the toner used in the developing device 5′ having the developing roller 25. (D50 particle size). The surface hardness of the surface crystallized part (high hardness part 30a") of the surface layer 25b is higher than that of the surface layer 25b in other parts of the recesses including the first and second inclined grooves 29a, 29b. The surface is harder. In addition, the toner chargeability of the surface layer 25b other than the surface crystallized portion (high hardness portion 30a″) of the surface layer 25b including the concave portions of the first and second inclined grooves 29a, 29b is lower than that of the high hardness portion 30a. "The toner has a higher chargeability.

Another example of the manufacturing method of the developing roller 25 of this example will be described.

As shown in FIG. 8(a), an amorphous surface layer 25b is formed on the surface of the base member 25a by electroless plating. At this time, the hardness of the surface layer 25b is set higher than the hardness of the base member 25a. Next, as shown in FIG. 8( b ), the amorphous surface layer 25 b is completely crystallized by annealing. The annealing temperature at this time is, for example, 300° C. or higher but not higher than the heat treatment temperature of the substrate 25 a. Next, as shown in FIG. 8(c), first and second inclined grooves 29a, 29b are formed on the surface of the base member 25a having the crystallized surface layer 25b by roll forming. At this time, the protrusion 30 is on the side closer to the top 30a than 1/2 of the depth of the first and second inclined grooves 29a, 29b, and is closer to the top 30a than 1/2 of the depth of the first and second inclined grooves 29a, 29b. One side of the base member 25a (the side opposite to the top portion 30a) is a concave portion. Then, the crystallized surface layer 25b in which the first and second inclined grooves 29a, 29b are formed is re-amorphized (amorphous) by rolling by roll forming. The surface hardness of the crystallized surface layer 25 b of the top 30 a is therefore greater than the surface hardness of the re-amorphized surface layer 25 b. Thus, the developing roller 25 of this example is formed.

Next, a specific example of the developing roller 25 of the present invention will be described.

The base material 25a of the developing roller 25 was made of STKM material having a hardness of Hv of 150, and the surface of the base material 25a was finished by centerless machining before processing the concave and convex portions on the base material 25a. Next, a substrate concave-convex portion having a depth of 6 μm was formed on the surface of the substrate 25a by roll forming. At this time, the base concave portions 29a', 29b' (the base concave portion bottom side of the base convex portion 30') are formed into a sinusoidal wave shape. In addition, the top 30a' side of the base protrusion 30' is formed in a truncated quadrangular pyramid shape. Furthermore, the side walls around the truncated pyramid shape are connected to the side walls around the sinusoidal curved recesses 29a', 29b', respectively. At this time, the point where the surrounding side walls of the truncated pyramid shape of the base member convex portion 30' connects to the surrounding side walls of the sine wave shape is a point 1/2 of the depth of the base member concave-convex portion.

As the surface layer 25b, a plating layer having a thickness t of 3 µm was formed on the surface of the base member by electroless nickel-phosphorus (Ni-P) plating. The surface hardness of the surface layer 25b at this time was 550 in terms of Hv. Next, the portion of the surface layer 25b on the top portion 30a was irradiated with an ion beam within a range of a depth t of 1.5 μm from the top surface of the protrusion 30 to crystallize the portion of the surface layer 25b by heating. The surface hardness of the crystallized surface layer 25b at this time was 1000 in terms of Hv. That is, the high-hardness part 30a" of the top part 30a has surface hardness larger than the part of the surface layer 25b other than this high-hardness part 30a".

Next, experiments were conducted regarding the toner chargeability of the developing roller of the present invention and the surface potential of the developing roller. The test is based on the measurement of the charge amount of the toner in the toner friction test and the surface potential test of the toner conveying surface of the developing roller.

In the toner rubbing test, as a sample of the developing roller, a sample plate in which the STKM material was formed into a surface layer with a thickness of 3 μm by electroless nickel-phosphorus (Ni—P) plating was produced. The surface hardness of this sample plate was 550 in Hv. Furthermore, another same sample plate was produced, and the surface layer of the sample plate was annealed at 400° C. for 2 hours to crystallize the surface layer. The surface hardness of this sample plate was 1000 in Hv. Therefore, it can be seen that the hardness of the surface layer is improved by the annealing treatment.

In addition, as the toner, the above-mentioned primary toner was used. Also, a blade made of urethane rubber used in the toner restricting member 26 was produced. Then, each sample plate was covered with toner, and the toner on each sample plate was rubbed with a scraper made of urethane rubber. Then, the charge amount of the rubbed toner was measured with a charge meter. The number of times of rubbing was increased, and after rubbing it for every predetermined number of times of rubbing, the charge amount of the toner was measured with a charge meter. Fig. 9(a) shows the results of the toner rubbing test at this time. As shown in FIG. 9( a ), it can be seen that the toner chargeability is good when the surface layer of the plated layer is not annealed.

On the other hand, in the surface potential test of the toner conveying surface of the developing roller, the aforementioned LP9000C printer was used as a driving test machine, and an experimental developing cartridge was also used. At this time, the driving test machine and experimental developing cartridge were modified so that the surface of the developing roller could be observed. In addition, a sample developing roller in which the STKM material was formed into a surface layer with a thickness of 3 μm by electroless nickel-phosphorus (Ni-P) plating, and a sample developing roller in which the surface layer was annealed at 400° C. for 2 hours in the same manner as described above were fabricated. One developer roll of the sample developer roll.

In addition, as the toner, the above-mentioned primary toner was used. Then, the experimental developing box was set on the driving test machine, and the driving test machine was idling. Then, part of the toner on the peripheral surface of the developing roller is removed to expose a part of the surface of the developing roller. Furthermore, a surface potentiometer was provided on the developing roller. In this state, the developing roller was rotated, the potential difference between the toner-removed part and the toner-unremoved part was measured, and the surface potential recovery rate was observed. 9(b) and (c) show the surface potential test at this time. As shown in FIGS. 9( b ) and ( c ), by the start of driving of the developing roller (DR), the surface potential of the developing roller increases. At this time, in each of the experimental results shown in FIGS. 9( b ) and ( c ), peaks at which the surface potential was bad periodically appeared at the start of driving the developing roller (DR). These peak portions with poor surface potential are portions where the toner is removed from the conveying surface. Moreover, when viewed as a whole, the surface potential of the one not subjected to the annealing treatment shown in FIG. 9( b ) is better than that of the one subjected to the annealing treatment shown in FIG. 9( c ). That is, it can be seen that the annealing treatment deteriorates the surface potential recovery property of the toner conveyance surface of the developing roller after toner development.

From these experiments, it was found that the surface of the top of the convex portion was crystallized during the annealing treatment to increase its hardness, and that the surface of the concave portion became amorphous without the annealing treatment, and the toner chargeability was improved.

According to the developing roller 25 of these examples, the surface hardness of the high-hardness portion 30a" of the top 30a of the convex portion 30 of the developing roller 25 is higher than that of the high-hardness portion 30a including the concave portion constituting the first and second inclined grooves 29a, 29b. The surface hardness of the parts other than " is set to be larger. Therefore, during image formation over a long period of time, the wear of the surface layer 25b of the top portion 30a, which is relatively easy to wear, is suppressed, and the wear of the surface layer 25b of the concave portion is also reduced. Therefore, compared with the conventional developing roller, the difference in wear between the convex portion and the concave portion can be further reduced. Accordingly, even if image formation is performed over a long period of time, the depth of the concavo-convex portion of the developing roller 25 does not change much. As a result, the amount of toner conveyed by the developing roller 25 hardly changes, and the image density can be kept almost constant over a long period of time. Therefore, favorable image development can be performed over a long period of time.

In addition, since the surface hardness of the concave portion of the developing roller 25 is small, filming at the concave portion having poor resetability can be prevented. Further, since the distance from the toner regulating blade 26 is long in the concave portion, the chargeability of the toner deteriorates. However, by maintaining the concave portion in an amorphous state, the decrease in the chargeability of the toner can be suppressed. That is, by making the toner chargeability of the concave portion higher than that of the convex portion, the toner can be charged more efficiently. Accordingly, toner coating, toner scattering, and the like can be suppressed, and favorable developing characteristics can be obtained.

Furthermore, in the toner conveying method in which toner is not conveyed to the surface of the convex portion 30 by the toner restricting member 26, the function of the concave portion such as ensuring the chargeability of the toner on the surface of the concave portion and the ensuring of the wear resistance of the surface of the convex portion are ensured. The function of the convex portion (maintenance of the depth of the concave-convex portion) is separated, and two functions can be realized.

Furthermore, by crystallizing the top portion 30a of the convex portion 30, the toner chargeability of the top portion 30a becomes less favorable. However, since the toner chargeability is not so good, excessive charging (charging) caused by sliding friction between the toner restricting blade 26 and the convex portion 30 of the developing roller 25 can be prevented instead, and the developing experience can be improved. In addition, when using toner with a smaller particle size than the depth of the unevenness of the developing roller, the tip of the toner limiting blade is brought into contact with the developing roller, and the toner is transported to the recesses of the developing roller and not to the convex parts. , can more effectively suppress the toner to the convex portion, and can prevent further toner filming or excessive charging on the convex flat surface.

Constitute the concavo-convex part of surface layer 25b with the same material, by making the degree of crystallization of the concave part and the convex part different (for example, the degree of crystallization of the convex part is higher than that of the concave part), the surface hardness and hardness of the convex part and the concave part can be controlled. resistance. At this time, each surface layer 25b of the convex portion and the concave portion was not completely crystallized (whether it was completely crystallized or not was analyzed by XRD). Accordingly, the surface composition of the developing roller can be easily created. In particular, if the hardness of the convex portion is increased and the abrasion thereof is excessively reduced, filming of toner welding occurs, but by controlling the degree of crystallization, the occurrence of filming can be suppressed.

Furthermore, by locally heating the surface layer 25b of the convex portion 30, the crystallization of the base material 25a is hardly affected. Therefore, warping or bending of the base member 25a caused by stress release of the base member 25a or a change in the degree of crystallization can be prevented.

Furthermore, by setting the range where the crystallization of the convex portion 30 proceeds from the upper surface of the convex portion 30 within the average particle diameter of the toner used, the toner transported to the concave portion where the chargeability is likely to decrease can be mixed with the amorphous material. concave contact. Therefore, it is possible to prevent the chargeability of the toner from being lowered.

Moreover, before forming the concavo-convex portion on the base 25a, the surface layer 25b is formed on the base 25a by electroless plating, so that even if a relatively difficult-to-process material is used for the base 25a, the surface layer 25b based on this plating can also be used. Improves the shape stability of the concavo-convex part. Accordingly, the smoothness of the surface of the uneven portion can be improved, the rotatability of the toner particles can be improved, and the filming of the toner on the uneven portion can be suppressed. Therefore, toner conveyance and toner chargeability can be maintained more favorably over a long period of time.

As shown in FIG. 11( a ), on the outer peripheral surface of the developing roller 25 , similarly to the developing roller described in Patent Document 1, a mesh-shaped concave-convex pattern is formed. In the developing roller 25 of this example, grooves 29 are formed over the entire periphery at predetermined positions in the axial direction on the outer peripheral surface as the concave-convex pattern. At this time, the groove 29 is formed in a helical shape successively inclined at a predetermined angle (45° in the illustrated example, but not limited thereto) with respect to the axial direction of the developing roller 25, and has a predetermined number of regular grooves. One slanted groove 29a and a predetermined number of second slanted grooves 29b are formed successively in a helical shape inclined oppositely to the inclination of the first slanted grooves 29a. These first and second inclined grooves 29a, 29b are formed at intervals p at a prescribed pitch in their inclined direction and at a prescribed width W in the axial direction. In addition, each inclination angle and each pitch of the first and second inclined grooves 29a, 29b can be different from each other.

As shown in FIG. 11(b), the developing roller 25 is composed of a base member 25a made of a relatively large work-hardened metal material, and a surface layer 25b formed on the outer peripheral surface of the base member 25a. The base member 25a is made of a sleeve made of a metal material such as aluminum such as 5056 aluminum alloy or 6063 aluminum alloy or iron such as STKM. In addition, the surface layer 25b is constituted by a plating layer such as nickel plating or chromium plating performed on the base member 25a.

As shown in Figure 11(d), on the outer peripheral surface of the base member 25a of the developing roller 25, first and second inclined grooves 29a, 29b for forming the first and second inclined grooves 29a, 29b are formed respectively by roll forming. Base grooves 29a', 29b'. The processing method of the first and second inclined base member grooves 29a', 29b' of the base member can adopt a conventionally known processing method. Therefore, description of this processing method is omitted. Furthermore, a predetermined number of island-shaped base protrusions 30' surrounded by first and second inclined base grooves 29a', 29b' are formed on the outer peripheral surface of the base 25a. In addition, in the present invention, the recessed part of the base refers to the side closer to the base 25a than 1/2 of the depth of the first and second inclined base grooves 29a', 29b', and the convex part of the base 30' refers to the Half of the depth of the first and second inclined base grooves 29 a ′, 29 b ′ protrudes outward from the base 25 a.

As shown in FIG. 11(d) and FIG. 12(a), the top of the base convex portion 30' is formed on the base flat portion 30a'. The shape of the base flat part 30a' of each base protrusion 30' is such that when the inclination angle of the first and second inclined base grooves 29a', 29b' is 45 degrees and their pitch p is set to be When they are the same, they form a square, and when the inclination angles of the first and second inclined base grooves 29a', 29b' are other than 45 degrees, and their pitch p is set to be the same as each other, they form a rhombus. In addition, the shape of the base flat part 30a' of each base protrusion 30' is such that when the inclination angle of the first and second inclined base grooves 29a', 29b' is 45 degrees, and their pitch p is set When the first and second inclined base grooves 29a', 29b' are different from each other, they form a rectangle. When the inclination angles of the first and second inclined base grooves 29a', 29b' are other than 45 degrees, and their pitches p are set differently, they form a parallelogram. In addition, regardless of the quadrangular shape of the base flat portion 30a', the base flat portion 30a' side of the base convex portion 30' inclines its surrounding side walls to form a truncated quadrangular pyramid.

Portions of the base recesses constituting the first and second inclined base grooves 29a', 29b' are respectively formed in curved recesses of sinusoidal concave surfaces along their inclination directions. Furthermore, the surrounding side walls of the truncated pyramid shape of the base convex portion 30' are formed continuously with the surrounding side walls of the sinusoidal curved concave portion of the base concave portion. At this time, the point where the surrounding side walls of the truncated pyramid shape of the base convex portion 30' and the surrounding side walls of the sinusoidal wave shape of the base concave portion connect is 1/2 of the depth of the concave-convex portion.

Moreover, as shown in Fig. 11(b), (c) and Fig. 12(a), the outer peripheral surface of the base member 25a formed by groove processing by roll forming is formed by work hardening by roll forming to form a high hardness portion 25a. '. This high-hardness portion 25a' is formed within a range of a substantially constant thickness _t1 from the outer peripheral surface of the base member 25a, and has a higher surface hardness than other portions of the base member 25a.

And the outer peripheral surface of the base 25a (that is, the surface of the high hardness portion 25a') forming the first and second inclined base grooves 29a', 29b' and the base flat portion 30a' of the base protrusion 30' Electroplating of an amorphous metal such as nickel-based plating forms a surface layer 25b on the surface of the base material 25a. At this time, the surface hardness of the surface layer 25b is smaller than the surface hardness of the high hardness portion 25a' of the outer peripheral surface of the base member 25a. In addition, the thickness _t1 of the surface layer 25b is set within the average particle diameter (D50 particle diameter) of the toner used. The recesses and protrusions of the first and second inclined grooves 29a, 29b are formed in the surface layer 25b in the same shape as the base recesses and base protrusions 30' of the first and second inclined base grooves 29a', 29b', respectively. Section 30.

The convex portion 30 forms a quadrangular flat top 30a. In addition, in the state where the surface layer 25b is formed on the base member 25a, the top 30a sides of the first and second inclined grooves 29a, 29b incline their surrounding side walls to form a truncated quadrangular pyramid shape. Furthermore, the side walls around the truncated pyramid shape are formed continuously with the side walls around the sine wave shape on the concave side of the first and second inclined grooves 29a, 29b.

On the other hand, the inventors of the present invention pointed out that the top h of the convex portion g of the developing roller a is relatively abraded into a flat shape as shown in FIG. The fact that the surface layer c forming the portion f hardly wears out was investigated while performing a durability test. In addition, the shape of the abrasion was measured with a laser microscope Keyence VK-9500 for three-dimensional measurement. The image forming apparatus used in the experiment was a printer of LP9000C manufactured by SEIKO EPSON. Also, instead of the developing roller used in this printer, the following developing roller 25 was used. At this time, in order to make the developing roller 25 usable, a printer of LP9000C manufactured by SEIKO EPSON was remodeled. The image forming conditions of the durability test are the standard image forming conditions of the LP9000C printer.

The STKM material was used for the base material 25a of the developing roller 25, and the surface finishing of the base material 25a was performed by centerless machining before processing the uneven|corrugated part to the base material 25a. Next, by roll forming, the first and second inclined base grooves 29a', 29b' are formed. Next, as the surface layer 25b, a plating layer having a thickness of 3 μm was formed on the surface of the base member by electroless nickel-phosphorus (Ni—P) plating. At this time, as shown in FIG. 13(a), the unevenness of the developing roller 25 has a depth of unevenness (height from the bottom of the grooves 29a, 29b to the top of the convex portion 30) of 6 μm, and a pitch of unevenness of 100 μm. The width of the 1/2-line convex portion 30 is 60 μm, and the width of the 1/2-line concave portion (grooves 29 a , 29 b ) is 40 μm.

In addition, the toner supply roller 24 is formed of a foamed urethane roller, and the developing roller 25 is provided with a cutting amount of 1.5 mm. Furthermore, the toner regulating blade 26 is composed of a blade made of urethane rubber, and is provided with a contact pressure of 40 g/cm with respect to the developing roller 25 .

Furthermore, the toners used are two types of toners. One of the toners is to add CCA, WAX, and pigments in an appropriate amount to the polyester particles made by the pulverization method to form toner master particles, and to add 20nm small particle diameter silicon dioxide to the toner master particles. Medium particle size silica of 40nm, large particle size silica of 100nm, and titanium dioxide of 30nm have an average particle size D50 of 4.5 μm, which is a small particle size toner smaller than the depth of unevenness of 6 μm. Another toner is a toner master particle formed by adding WAX and pigments to the styrene propylene particles made by the polymerization method, and adding 20nm small particle size silica and 40nm medium to the toner master particle. Silica with a particle size of 100 nm, silicon dioxide with a large particle size of 100 nm, and titanium dioxide with a particle size of 30 nm. The average particle size D50 is a toner with a small particle size of 4.5 μm similar to the above-mentioned toner.

Then, under the standard image forming conditions of LP9000C, a durable image forming experiment was performed on A4 plain paper with a monochromatic character pattern having an image occupancy rate of 5%. As a result of this experiment, the top 30a of the surface layer 25b of the convex portion 30 having the initial profile indicated by the solid line in FIG. profile tendencies. Such a flat wear profile of the convex portion 30 tends to wear into the same curved profile even when the second small particle size toner is used.

The reason for this is considered to be as follows. In FIG. 6(a), along with the rotation of the developing roller 25, the toner particles located on the flat surface 30a of the convex portion 30 pass through the toner supply roller 24 and the toner limiting blade 26 which are in pressure contact with the developing roller 25, respectively. Move into the first and second inclined grooves 29a, 29b, respectively. At this time, in FIG. 6(a), the toner particles located at the top 30a of the convex portion 30 move into the first and second inclined grooves 29a, 29b, respectively, as the developing roller 25 rotates. At this time, since the average particle size (D50 particle size) of the toner particles is smaller than the depth of the concave-convex portion, the particles of the toner 28 moving into the first and second inclined grooves 29a, 29b form multiple layers. Further, the toner particles located in the first and second inclined grooves 29a, 29b move to the tops 30a of the protrusions 30 as the developing roller 25 rotates. At this time, the position of the toner particles of the uppermost layer is almost at the same height position as the top 30a of the convex portion 30, so among the particles of the toner 28 located in the first and second inclined grooves 29a, 29b, the uppermost layer is mainly The toner particles in the upper layer move roughly laterally, and the toner particles in the lower layer hardly move. Due to the lateral movement of the toner particles in the uppermost layer, the surface of the surface layer 25b gradually wears flat over a long period of time due to the relatively hard external additive on the surface of the toner particles, as shown in FIG. 6(b).

6( a ) and ( b ) are cross-sectional views along the inclination direction of the first and second inclination grooves 29 a and 29 b like in FIG. 11 ( b ). Therefore, the partial cross sections of these developing rollers 25 are different from the rotational directions of the developing rollers 25 . Therefore, the toner particles located in the first inclined groove 29a move to the top 30a of the protrusion 30, and then, the toner on the top 30a also moves to the first and second inclined grooves 29a, 29a, and 29a adjacent to the top 30a. Either of 29b. In addition, the toner particles located in the second inclined groove 29b move to the top 30a of the convex portion 30, and then, the toner on the top 30a also moves to the first and second inclined grooves 29a, 29a, and 29a adjacent to the top 30a. Either of 29b. The same applies to the description of other examples below.

However, the developing roller 25 of this example is initially used in a state where the surface layer 25b is formed on the base flat portion 30a' of the base convex portion 30' as shown in FIG. 12(a). Then, if the surface layer 25b on the base flat portion 30a' wears away during image formation over a long period of time, as shown in FIGS. 11(c) and 12(b), the base of the base protrusion 30' The piece flat portion 30a' is exposed. The surface hardness of the base flat portion 30a' is greater than that of the surface layer 25b of the first and second inclined grooves 29a, 29 (i.e., recessed portions of the developing roller 25) by work hardening. Therefore, if the base flat portion 30a' of the base protrusion 30' is exposed, the wear rate of the protrusion 30 of the developing roller 25 by the toner restricting blade, toner supply roller, or toner external additive decreases. Accordingly, the durability of the developing roller 25 is improved. In addition, if the surface layer 25b on the base flat portion 30a' is reduced, the depth of the concave-convex portion of the developing roller 25 will change somewhat, but the abrasion of the exposed base flat portion 30a' can be suppressed, so the abrasion of the convex portion 30 Speed drops. Therefore, as a whole, the change in the depth of the uneven portion of the developing roller 25 can be suppressed over a long period of time.

An example of a method of manufacturing the developing roller 25 of this example configured in this way will be described.

As shown in Fig. 14(a), first and second inclined base grooves 29a', 29b' are formed on the base 25a by roll forming. The high hardness portion 25a' is formed on the outer peripheral surface of the base member 25a by the work hardening by the groove processing. Next, as shown in FIG. 14(b), a surface layer 25b of one layer of amorphous metal is formed on the surface of the high hardness portion 25a' of the base material 25a by electroless plating. Accordingly, the first and second inclined grooves 29a, 29b are formed corresponding to the first and second inclined base grooves 29a', 29b'. At this time, the protrusion 30 is on the side closer to the top 30a than 1/2 of the depth of the first and second inclined grooves 29a, 29b, and is closer to the top 30a than 1/2 of the depth of the first and second inclined grooves 29a, 29b. One side of the base member 25a (the side opposite to the top portion 30a) is a concave portion. At this time, the surface hardness of the high-hardness portion 25a' of the base member 25a is set higher than the hardness of the surface layer 25b. Thus, the developing roller 25 of this example shown in Fig. 14(a) is formed in which the surface layer 25b is formed on the base flat portion 30a' of the base convex portion 30'. Then, if the surface layer 25b on the base flat portion 30a' of the base protrusion 30' is worn and reduced during image formation over a long period of time, as shown in FIG. 12(b), the base protrusion 30' The base flat portion 30a' is exposed.

In addition, the developing roller 25 of this example does not necessarily have to form the surface layer 25b on the base flat portion 30a' of the base convex portion 30' initially as shown in Fig. 12(a). That is, the developing roller 25 can be used in a state where the surface layer 25b on the base flat portion 30a' shown in FIG. 12(a) is initially removed to expose the base flat portion 30a' shown in FIG. 12(b). As a method of removing the surface layer 25b on the base flat portion 30a', a conventionally known method of grinding with a grinder or a method of grinding with a grinder can be used.

Next, a specific example of the developing roller 25 of this example will be described.

The base 25a of the developing roller 25 was made of SUS material having a hardness of 250 in Hv, and the surface of the base 25a was finished by centerless machining before processing the unevenness on the base 25a. Next, by roll forming, a base concave-convex portion having a depth of 8 μm was formed on the surface of the base 25a. At this time, the base recesses 29a', 29b' (the bottom side of the base recess of the base protrusion 30') form a sinusoidal wave shape. In addition, the top 30a' side of the base protrusion 30' is formed in a truncated quadrangular pyramid shape. Then, the surrounding side walls of the truncated pyramid shape are respectively connected to the surrounding side walls of the sinusoidal curved recesses 29a', 29b'. At this time, the point where the surrounding side walls of the truncated pyramid shape of the base member convex portion 30' connects to the surrounding side walls of the sine wave shape is a point 1/2 of the depth of the base member concave-convex portion. At this time, the SUS material which is the material of the base material 25a undergoes relatively large work hardening, so the surface hardness of the base material 25a by roll forming is 700 in terms of Hv.

As the surface layer 25b, a plated layer having a thickness _t1 of 1.5 µm was formed on the surface of the base member by electroless nickel-phosphorus (Ni-P) plating. The surface hardness of the surface layer 25b at this time was 500 in terms of Hv. Thus, the developing roller 25 of this example is formed.

Then, using the developing roller 25 of this example, a durability test similar to the above-mentioned durability test was carried out. As shown in FIG. .

15( a ) and ( b ) are partial enlarged cross-sectional views similar to those in FIGS. 12( a ) and ( b ), respectively, showing other examples of embodiments of the developing roller of the present invention.

In the example described above, the surface layer 25b is formed as one layer, however, as shown in FIG. The surface layer 25b". At this time, the first surface layer 25b' is formed on the outer peripheral surface of the base member 25a, and the second surface layer 25b" is formed on the outer peripheral surface of the first surface layer 25b'. Moreover, the thickness _t2 of the first surface layer 25b' is set to be larger than the thickness _t3 of the second surface layer 25b". At this time, the thickness _t3 of the second surface layer 25b" is set at the thickness of the toner used. Within the average particle size (D50 particle size). In addition, the surface hardness of the first surface layer 25b' adjacent to the inner side of the second surface layer 25b" which is the outermost surface layer is set to be larger than the surface hardness of the second surface layer 25b". Furthermore, the toner chargeability of the second surface layer 25b" is set to be higher than the toner chargeability of the first surface layer 25b' adjacent to the inner side of the second surface layer 25b".

In the developing roller 25 of this example, it is not necessary to use a metallic material that undergoes such a large work hardening for the base member 25a. Of course, as mentioned above, it is also possible to use a metal material that undergoes relatively large work hardening for the base member 25a.

Other structures of the developing roller 25 of this example are the same as those of the above-described example. In addition, the developing roller 25 can be used in the developing device 5' and the image forming device 1 as described above.

However, the developing roller 25 of this example is initially used as shown in FIG. After a long period of image formation, the second surface layer 25b" of the base flat portion 30a' wears away, and as shown in FIG. 15(b), the flat portion of the first surface layer 25b' of the base flat portion 30a' 30a" is exposed. The surface hardness of the first surface layer 25b' is greater than that of the second surface layer 25b" of the first and second inclined grooves 29a, 29 (that is, the recesses of the developing roller 25). Therefore, if the flat portion 30a" of the first surface layer 25b' of the base flat portion 30a' is exposed, the abrasion of the convex portion 30 of the developing roller 25 based on the toner limiting blade, the toner supply roller, or the toner external additive The speed decreases. Accordingly, the durability of the developing roller 25 is improved. In addition, if the second surface layer 25b" of the base flat portion 30a' is reduced, the depth of the concave-convex portion of the developing roller 25 will be somewhat changed, but it can be suppressed. The abrasion of the first surface layer 25b', so the abrasion speed of the protrusion 30 is reduced. Therefore, as a whole, the change in the depth of the uneven portion of the developing roller 25 can be suppressed over a long period of time. In addition, the developing roller 25 is not limited to two layers, and may be formed in multiple layers of three or more layers. At this time, the surface hardness of the surface layer adjacent to the inner side of the outermost surface layer of the developing roller 25 is set to be greater than the surface hardness of the outermost surface layer.

In the manufacturing method of the developing roller 25 of this example thus constituted, the first surface layer 25b' is formed on the outer peripheral surface of the unevenly processed base member 25a by electroless plating of an amorphous metal. Next, the first surface layer 25b' is heat-treated by annealing or the like to advance crystallization and increase hardness. This crystallization can be ascertained by XRD analysis. Next, on the outer peripheral surface of the first surface layer 25b', the second surface layer 25b" is formed by electroless plating of an amorphous metal or a crystallized metal. At this time, when an amorphous metal is used for the second surface layer 25b", In the case of metal, the temperature of electroplating and the metal ratio of the electroplating solution are changed to form a second surface layer 25b "more amorphous than the first surface layer 25b'. The other parts of the manufacturing method are the same as those shown in Fig. 14(a) The manufacturing method of the developing roller 25 of the described example shown in～(c) is substantially the same.In addition, the developing roller 25 of this example is also the same as the described example, and the second part of the base flat portion 30a' is initially formed. It is used in the state of the surface layer 25b". Moreover, if the second surface layer 25b" of the base flat portion 30a' of the base protrusion 30' is worn and reduced during image formation for a long time, as shown in FIG. 15(b), the base protrusion 30 'The base flat portion 30a' is exposed.

In addition, the developing roller 25 of this example is the same as the above-mentioned example, and it is not necessary to first form the second surface layer 25b" on the base flat portion 30a' of the base protrusion 30' as shown in FIG. 15(a). That is, the developing roller 25 can also remove the second surface layer 25b" of the base flat portion 30a' shown in FIG. It is used in the state of the first surface layer 25b'. As a method of removing the second surface layer 25b ″, a conventionally known method of grinding with a grinder or a method of grinding with a grinder can be used.

Next, a specific example of the developing roller 25 of this example will be described.

The base material 25a of the developing roller 25 was made of STKM material having a hardness of Hv of 150, and the surface of the base material 25a was finished by centerless machining before processing the concave and convex portions on the base material 25a. Next, by roll forming, a base concave-convex portion having a depth of 8 μm was formed on the surface of the base 25a. In this case, the shapes of the base recesses 29a', 29b' (the bottom side of the base recess 30' of the base protrusion 30') are the same as those of the above-mentioned example.

Next, as the first surface layer 25b', a plated layer having a thickness _t2 of 3 μm was formed on the base surface by amorphous electroless nickel-phosphorous (Ni-P) plating. Then, the plating layer was annealed at 400° C. to crystallize nickel-phosphorus in the plating layer. The surface hardness of the first surface layer 25b' at this time was 1000 in terms of Hv. Next, as the second surface layer 25b", a plating layer with a thickness _t2 of 1.5 μm was formed on the surface of the first surface layer 25b' by amorphous electroless nickel-phosphorus (Ni-P). At this time, The surface hardness of the second surface layer 25b" was 500 in Hv. Thus, the developing roller 25 of this example is formed.

Then, using the developing roller 25 of this example, the same durability test as the above-mentioned durability test was carried out. As shown in FIG. .

Next, experiments were conducted on the toner chargeability of the developing roller of the present invention and the surface potential of the developing roller. The test is based on the measurement of the charge amount of the toner in the toner friction test and the surface potential test of the toner conveying surface of the developing roller.

In the toner rubbing test, as a sample of the developing roller, a sample plate in which the STKM material was formed into a surface layer with a thickness of 3 μm by electroless nickel-phosphorus (Ni—P) plating was produced. The surface hardness of this sample plate was 550 in Hv. Furthermore, another same sample plate was produced, and the surface layer of the sample plate was annealed at 400° C. for 2 hours to crystallize the surface layer. The surface hardness of this sample plate was 1000 in Hv. Therefore, it can be seen that the hardness of the surface layer is improved by the annealing treatment.

In addition, as the toner, the above-mentioned primary toner was used. A blade made of urethane rubber used in the toner restricting member 26 was fabricated. Then, each sample plate was covered with toner, and the toner on each sample plate was rubbed with a scraper made of urethane rubber. Then, the charge amount of the rubbed toner was measured with a charge meter. The number of times of rubbing was increased, and after rubbing it for every predetermined number of times of rubbing, the charge amount of the toner was measured with a charge meter. Fig. 9(a) shows the results of the toner rubbing test at this time. As shown in FIG. 9( a ), it can be seen that the toner chargeability is good when the surface layer of the plated layer is not annealed.

On the other hand, in the surface potential test of the toner conveying surface of the developing roller, the aforementioned LP9000C printer was used as a driving test machine, and an experimental developing cartridge was used. At this time, the driving test machine and experimental developing cartridge were modified so that the surface of the developing roller could be observed. In addition, a sample developing roller in which STKM material was formed into a surface layer with a thickness of 3 μm by electroless nickel-phosphorus (Ni-P) was fabricated, and the surface layer was annealed at 400° C. for 2 hours in the same manner as described above. A developer roll of the sample developer roll. In addition, as the toner, the above-mentioned primary toner was used. Then, the experimental developing box was set on the driving test machine, and the driving test machine was idling. Then, part of the toner on the peripheral surface of the developing roller was removed to expose a part of the surface of the developing roller. A surface potentiometer was installed on the developing roller. In this state, the developing roller was rotated, the potential difference between the toner-removed part and the toner-unremoved part was measured, and the surface potential recovery rate was observed. 9(b) and (c) show the surface potential test at this time. As shown in FIGS. 9( b ) and ( c ), by the start of driving of the developing roller (DR), the surface potential of the developing roller increases. At this time, in each of the experimental results shown in FIGS. 9( b ) and ( c ), peaks at which the surface potential was bad periodically appeared at the start of driving the developing roller (DR). These peak portions with poor surface potential are portions where the toner is removed from the conveyance surface. Moreover, when viewed as a whole, the surface potential is better in the one not subjected to the annealing treatment shown in FIG. 9( b ) than in the one subjected to the annealing treatment shown in FIG. 9( c ). That is, it can be seen that the annealing treatment deteriorates the surface potential recovery property of the toner conveyance surface of the developing roller after toner development.

According to these experiments, the surface of the top of the convex part was crystallized during the annealing treatment, and its hardness was increased, and the surface of the concave part became amorphous without annealing treatment, and the toner chargeability was improved.

According to the developing roller 25 of these examples, when the base member 25a forms the one-layer surface layer 25b, the surface hardness of the base member 25a is set to be greater than the surface hardness of the outermost surface layer 25b. In addition, when the base member 25a forms the multilayer surface layer 25b, the surface hardness of the first surface layer 25b' adjacent to the inner side of the outermost surface layer, that is, the second surface layer 25b" is higher than that of the second surface layer 25b". The surface hardness is set to be larger. Therefore, by image formation, the surface layer 25b of the base flat portion 30a' of the base convex portion 30' or the second surface layer 25b" of the base flat portion 30a' is formed by the toner limiting member, the developing roller, or the toner external additive. If these base flat portions 30a' or the first surface layer 25b' are exposed due to abrasion, the abrasion rate of the protrusions 30 of the developing roller 25 decreases. This improves the durability of the developing roller 25.

In addition, if the surface layer 25b or the second surface layer 25b" of the base flat portion 30a' is reduced, the depth of the concavo-convex portion of the developing roller will vary somewhat, but the exposure of the base flat portion 30a' or the first surface can be suppressed. wear of the layer 25b'. Therefore, as a whole, the change in the depth of the concave-convex portion of the developing roller 25 can be suppressed for a long time, and the depth of the concave-convex portion can be well maintained for a long time. As a result, the color transported by the developing roller 25 The powder hardly changes, and the image density can be maintained almost constant over a long period of time. Therefore, good development can be performed over a long period of time.

In addition, due to the exposed base flat portion 30a' of the convex portion 30 or the first surface layer 25b', the toner chargeability is lowered, but the toner particles are sandwiched between the developing roller 25 and the toner limiting blade 26', and the friction Since the force is greater than that of the concave portion, this portion can suppress a decrease in the chargeability of the toner. Accordingly, toner coating, toner scattering, and the like can be suppressed, and favorable developing characteristics can be obtained.

Furthermore, in the toner conveying method in which the toner limiting blade 26 does not convey toner to the surface of the convex portion 30, the function of the concave portion such as ensuring the chargeability of the toner on the surface of the concave portion and the wear resistance of the surface of the convex portion The functions of the convex portion such as securing (maintenance of the depth of the concave-convex portion) are separated, and two functions can be realized.

And, by setting the thickness of the surface layer 25b of one layer or the thickness of the second surface layer 25b" within the average particle diameter (D50 particle diameter) of the toner used, it is possible to make the toner transported to the concave portion where the chargeability is easy to decline. The toner is in contact with the concave portion of the amorphous metal, so that the chargeability of the toner can be prevented from being lowered.

In addition, even if the surface layer 25b or the second surface layer 25b" of one layer is removed by grinding with a grinder or grinding with a grinder, the base protrusion 30' of the base 25a is used from the beginning. The base flat portion 30a' or the developing roller 25 in a state where the first surface layer 25b' of the base flat portion 30a' is exposed can also achieve the same effect as described above.

According to the developing device 5' having the developing roller 25, the electrostatic latent image on the photoreceptor 3 can be developed satisfactorily over a long period of time. On the other hand, the image forming apparatus 1 including the developing device 5' can form an image with stable density and good image quality over a long period of time.

In addition, in the present invention, the axial interval and the number of the second inclined grooves 29b are not necessarily the same as the intervals and the number of the first inclined grooves 29a, and may be different. In addition, the number of the first and second inclined grooves 29a, 29b can be set to an arbitrary number of one or more.

In addition, when a relatively hard silica toner is used as an external additive and a toner with a silica coverage rate of 100% or more relative to the toner mother particle is used, because the surface of the toner mother particle Since there is a large amount of silica, the abrasion rate of the surface layer 25b of the convex portion 30 becomes relatively fast. Therefore, even if the developing roller 25 of this example is used in the developing device 5' using toner having a silica coverage of 100% or more, the durability of the developing roller 25 can be improved more effectively.

Also, the base recess formed by the first and second inclined base grooves 29a', 29b' does not necessarily have to be formed in a sinusoidal shape. The recessed portion of the base member can be formed with other curved surfaces, and can be formed in the shape of an inverse truncated quadrangular pyramid having a bottom of a flat surface. In this case, at the inflection point (a position approximately 1/2 of the depth of the concave-convex portion of the base), it is formed so as to be continuous with the truncated pyramid shape of the convex portion of the base.

Also, in the example described above, application is made to the image forming apparatus 1 having the rotary developing unit 5, but the present invention is not limited thereto. For example, the present invention can also be used in an image forming apparatus arranged in series with image forming units, a 4-cycle image forming apparatus, a monochrome image forming apparatus, or directly transfer a toner image from a latent image carrier to a reproduction material (equivalent to the present invention). Any type of image forming apparatus including a developing device provided with a developing roller having at least a concavo-convex portion, such as an image forming apparatus that replicates from an intermediate reproduction medium (ie, an image forming apparatus that does not have an intermediate reproduction medium). Mainly, the present invention can be applied to any image forming apparatus within the scope described in the claims.

Claims (20)

1. developer roll has at least:

Substrate, it has substrate recess and the substrate protuberance that forms in the regulation zone of outer peripheral face; With

Superficial layer, it is formed on the outer peripheral face of this substrate, and has and described substrate recess and described substrate protuberance difference corresponding concave part and protuberance at outer peripheral face,

The skin hardness of the protuberance of the outer peripheral face of described superficial layer is bigger than the skin hardness of the recess of the outer peripheral face of described superficial layer.

2. developer roll according to claim 1 is characterized in that,

About the charging property of the toner of the jog of the outer peripheral face of described superficial layer, the charging property of the recess of the outer peripheral face of described superficial layer is higher than the charging property of the protuberance of the outer peripheral face of described superficial layer.

3. according to any described developer roll in the claim 1～2, it is characterized in that,

In the superficial layer of the superficial layer of described substrate recess and described substrate protuberance, the degree of crystallization of the superficial layer of described substrate recess is higher than the degree of crystallization of the superficial layer of described substrate protuberance.

4. according to any described developer roll in the claim 1～2, it is characterized in that,

The all incomplete crystallization of the superficial layer of the superficial layer of described substrate recess and described substrate protuberance.

5. developer roll according to claim 1 is characterized in that,

Described superficial layer is made of 1 layer or multilayer,

When described superficial layer is 1 layer, the skin hardness of described substrate protuberance is bigger than the skin hardness of the superficial layer of described protuberance, perhaps when described superficial layer is multilayer, bigger than the skin hardness of described outermost superficial layer with the skin hardness of the inboard adjacent superficial layer of outermost described superficial layer.

6. developer roll according to claim 1 is characterized in that,

Described superficial layer is made of 1 layer or multilayer,

When described superficial layer was 1 layer, exposed at the top of described substrate protuberance, perhaps when described superficial layer is multilayer, exposes with the inboard adjacent superficial layer of the outermost superficial layer at the top of described substrate protuberance.

7. according to any described developer roll in the claim 5～6, it is characterized in that,

When described superficial layer was 1 layer, the thickness of described superficial layer was littler than the mean grain size of employed toner, and perhaps when described superficial layer was multilayer, described outermost thickness was littler than the mean grain size of employed toner.

8. according to any described developer roll in the claim 1,2,5,6, it is characterized in that,

Described superficial layer forms by plated by electroless plating.

9. developing apparatus has at least:

Developer roll, it is held body with toner to the sub-image load and carries;

The toner donor rollers, itself and this developer roll butt is supplied with described toner; With

Toner limits member, and itself and described developer roll butt limit the amount of holding the toner of body conveying to described sub-image load,

Described developer roll is any described developer roll in the claim 1～4,

The mean grain size of described toner is littler than the concave depth of the outer peripheral face of the described superficial layer of described developer roll.

10. developing apparatus according to claim 9 is characterized in that,

Described toner limits member and is made of the scraper plate that elastic body constitutes, the front end of described scraper plate and described developer roll butt, and perhaps the front end of scraper plate is present in the qualification impression portion.

11. an image processing system, it has at least:

The sub-image load is held body, and it forms electrostatic latent image at least;

Developing apparatus, it develops with noncontact and by toner described electrostatic latent image is developed, and holds formation toner picture on the body in described sub-image load; With

Reproducing unit, its toner that described sub-image load is held body looks like to copy on the replicating medium,

Described developing apparatus is the described developing apparatus of claim 10.

12. the manufacture method of a developer roll comprises:

Form the operation of substrate jog on the whole at the image forming area at least of substrate;

After the concavo-convex processing of substrate, cover and form the operation of superficial layer with the noncrystalline metal to major general's image forming area is whole; With

To cover the operation that noncrystalline metal on the substrate protuberance of described substrate jog carries out crystallization,

In this manufacture method, set the skin hardness of described substrate higher than the skin hardness of described superficial layer.

13. the manufacture method of developer roll according to claim 12 is characterized in that,

By rolling forming processing, form described substrate jog.

14. a developing apparatus has at least:

Developer roll, it is held body with toner to the sub-image load and carries;

The toner donor rollers, itself and described developer roll butt are supplied with described toner;

Toner limits member, and itself and described developer roll butt limit the amount of holding the toner of body conveying to described sub-image load;

Described developer roll is any described developer roll in the claim 5～7,

The mean grain size of described toner is littler than the concave depth of the outer peripheral face of the described superficial layer of described developer roll.

15. developing apparatus according to claim 14 is characterized in that,

It is elastic body that described toner limits scraper plate, and described toner limits the front end and the described developer roll butt of scraper plate, and perhaps the front end of toner qualification scraper plate is present in the qualification impression portion.

16. an image processing system, it has at least:

The sub-image load is held body, and it forms electrostatic latent image at least;

Developing apparatus, it develops with noncontact and by toner described electrostatic latent image is developed, and holds formation toner picture on the body in described sub-image load; With

Reproducing unit, its toner that described sub-image load is held body looks like to copy on the replicating medium,

Described developing apparatus is claim 14 or 15 described developing apparatuss.

17. the manufacture method of a developer roll comprises:

Form the operation of substrate jog on the whole at the image forming area at least of substrate; With

After the concavo-convex processing of substrate, to the whole operation that forms 1 layer or multiple-level surface layer with 1 layer of noncrystalline metal covering or multilayer of major general's image forming area,

In this manufacture method, when on described substrate, forming 1 laminar surface layer, set the skin hardness of described substrate higher than the skin hardness of above-mentioned 1 laminar surface layer, when on described substrate, forming the multiple-level surface layer, will set highlyer with the skin hardness of the inboard adjacent superficial layer of outmost surface layer than the skin hardness of outmost surface layer.

18. the manufacture method of developer roll according to claim 17 is characterized in that,

Cover the operation of the superficial layer of described multilayer, have: the operation that further covers and noncrystalline metal that toner charging property high lower in described noncrystalline metal surface than described noncrystalline hardness.

19. the manufacture method of developer roll according to claim 17 is characterized in that, has:

Further heat described noncrystalline metal, and make the operation of its crystallization; With

Further cover the operation of noncrystalline metal on the noncrystalline metal surface having carried out described heating behind the crystallization.

20. the manufacture method of developer roll according to claim 17 is characterized in that, has:

When being 1 layer, described superficial layer removes the noncrystalline metal of the described 1 laminar surface layer of substrate protuberance, perhaps the operation of outermost noncrystalline metal in the noncrystalline metal of the described multiple-level surface layer at the top of removal substrate protuberance when described superficial layer is multilayer.

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