JP2014077885A - Developer carrier, developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer carrier capable of improving durability while suppressing the occurrence of filming of developer when used in a developing device, a developing device including the developer carrier, a process cartridge, and an image forming apparatus.SOLUTION: A developing roller 42 that is a developer carrier includes concave parts 42b and convex parts 42a on the surface thereof forming a concave-convex shape, and carries a toner that is a developer on the surface to make surface movement to convey the developer. The convex parts 42a forming the concave-convex shape are in an elliptical frustum shape, and the longitudinal direction of the elliptical frustum shape is a direction along the direction of the surface movement.

Description

  The present invention relates to a developer carrier provided in a developing device used in a copying machine, a facsimile, a printer, and the like, and a developing device, a process cartridge, and an image forming apparatus including the developer carrier.

  In Patent Documents 1 to 3, the height of the convex portions and the depth of the concave portions are regularly fixed on the surface of the developing roller that conveys the toner to the developing area that is the facing portion of the photosensitive member that is the latent image carrier. A developing device is described in which irregularities having various patterns are formed. In this developing device, the developer in the developer container is supplied to the surface of the developing roller by the developer supplying member, and the toner on the convex portion of the developing roller is scraped off by the regulating member, so that the toner on the surface of the developing roller is removed. Is only the toner contained in the recess. Since the depth of the concave portion is constant and the formation pattern is regular, the toner carrying amount is substantially stabilized over the circumference of the developing roller. In such a developing device, a desired amount of toner can be transported to the developing region by setting the capacity of the recess to a capacity for carrying a desired amount of toner.

In Patent Documents 1 and 2, two types of spiral groove portions having different inclinations with respect to the surface movement direction of the developing roller intersect each other to form a lattice-shaped concave portion, and a square frustum shape is formed in a portion of the lattice. A developing roller having a convex portion is described.
Japanese Patent Application Laid-Open No. H10-228561 describes that the convex portion on the surface of the developing roller has a truncated cone shape.

  In the developing rollers described in Patent Documents 1 and 2, none of the four sides forming the quadrangular pyramid-shaped upper surface (hereinafter referred to as the top surface) of the convex portion is parallel to the rotation axis of the developing roller. . With respect to the surface movement direction of the developing roller, the portion on the most downstream side on the top surface is one of the four corners of a quadrangle.

  As described in Patent Documents 1 and 2, when the edge portion on the most downstream side on the top surface is a corner, the contact pressure when the regulating member starts to contact a certain convex portion is one point of the corner. It becomes a state to concentrate on. When the contact pressure is concentrated on one point, the portion of the restricting member that comes into contact with the corner accelerates wear compared to the other portions. If there is a portion where the progress of wear is partly fast in the regulating member, it will lead to a decrease in durability over time. In addition, when the contact pressure is concentrated at one point, the corner of the developing roller surface is likely to be worn, and if the corner is worn, the capacity of the concave portion is increased, and the transportability with time changes. And this leads to a decrease in durability.

  On the other hand, when the convex portion is in the shape of a truncated cone as in the developing roller described in Patent Document 3, the most downstream portion of the top surface is a part of the circumference, and the contact pressure is concentrated at one point. Due to the above, it is possible to suppress the wear of the regulating member from partially developing. Moreover, it can suppress that a convex part wears down resulting from contact pressure concentrating on one point. Therefore, durability can be improved compared with the case where the most downstream part of the top surface is a corner.

  However, when the shape of the top surface is a circle, the shape of the edge portion from the edge portion on the most downstream side toward the upstream side on the top surface is large in the axial direction of the developing roller (direction perpendicular to the surface movement direction). While spreading, it has a shape toward the upstream side in the surface movement direction. For this reason, when the toner regulated by the regulating member comes into contact with the edge on the downstream side of the top surface, the movement of the toner in the direction along the surface movement direction may be insufficient. When the movement of the toner in the direction along the surface movement direction becomes insufficient, the toner sandwiched between the circumferential edge portion including the most downstream end portion on the top surface and the regulating member is compressed. As a result, toner filming occurs.

  The present invention has been made in view of the above problems, and a purpose thereof is a developer capable of improving durability while suppressing the occurrence of filming of the developer when used in a developing device. It is an object to provide a carrier, and a developing device, a process cartridge, and an image forming apparatus including the carrier.

  In order to achieve the above object, the invention according to claim 1 is a developer carrying member having a concavo-convex shape on a surface, carrying the developer on the surface, and transporting the developer by moving the surface, wherein the concavo-convex shape is provided. The convex part to be formed has an elliptic frustum shape, and its long axis direction is a direction along the surface movement direction.

  In the present invention, since the convex portion is in the shape of an elliptic frustum, the restricting member is partially caused by the contact pressure being concentrated at one point as in the configuration in which the convex portion is in the shape of a truncated cone. It is possible to suppress the progress of wear and the wear of the convex portion. For this reason, durability can be improved.

  In the present invention, since the major axis direction of the elliptical truncated cone shape is the direction along the surface movement direction, the direction orthogonal to the surface movement direction is the minor axis direction, and the shape of the top surface is an ellipse that is long in the surface movement direction. It becomes a shape. In such a shape, the shape of the edge portion going from the edge portion serving as the most downstream end portion on the top surface to the upstream side is a shape having a smaller spread in the direction perpendicular to the surface movement direction than in the case of a circular shape. Become. For this reason, it becomes easier for the developer to move in the direction along the surface movement direction along the edge than in the case where the top surface is circular, the edge portion including the most downstream end portion on the top surface, the regulating member, It is possible to suppress the developer from being sandwiched between the two. Therefore, it is possible to suppress the occurrence of filming of the developer due to the developer sandwiched between the edge portion on the top surface and the regulating member being compressed.

  According to the present invention, when used in a developing device, there is an excellent effect that durability can be improved while suppressing the occurrence of filming of a developer.

Explanatory drawing of the surface shape of the developing roller, (a) is a schematic diagram of the entire developing roller, (b) is an enlarged top view of the region η in (a), (c) is an E- in (b). Sectional drawing of an E 'cross section. 1 is a schematic configuration diagram of a copier according to a first embodiment. FIG. 2 is a schematic configuration diagram of a developing device according to the first embodiment. FIG. 3 is a first perspective explanatory view of the developing device according to the first embodiment. FIG. 3 is a second perspective explanatory view of the developing device according to the first embodiment. FIG. 3 is an explanatory cross-sectional view of the developing device according to the first embodiment. FIG. 3 is a perspective view illustrating a part of the developing device according to the first embodiment in a cross-sectional view. FIG. 3 is an enlarged perspective view of the vicinity of one end of the developing device, with the lower case not shown. FIG. 9 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 8. FIG. 4 is an enlarged perspective view of the vicinity of the other end of the developing device, with the lower case not shown. FIG. 11 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 10. FIG. The side view of a developing roller. The perspective explanatory view of a supply roller. The side view of a supply roller. The perspective explanatory drawing of a doctor blade. The side view of a doctor blade. FIG. Side view of paddle. FIG. 3 is an enlarged explanatory view of a doctor portion of a developing device in a state where a doctor blade is placed on the stomach. FIG. 3 is an enlarged explanatory view of a doctor unit of a developing device in a state where a doctor blade is in a tip contact state. The expanded sectional view of the surface of the developing roller whose angle which the side surface of a convex part and the bottom face of a recessed part comprise is less than 90 [degree]. FIG. 4 is an enlarged cross-sectional view of the surface of a developing roller in which a part of an angle formed by a side surface of a convex portion and a bottom surface of a concave portion is less than 90 [°]. The expanded sectional view of the surface of the developing roller whose angle which the side surface of a convex part and the bottom face of a recessed part make is 90 [degrees] or more. The expanded sectional view of the surface of the developing roller whose angle which the side surface of a convex part and the bottom face of a recessed part make is 90 degrees. FIG. 3 is an enlarged cross-sectional view of the surface of the developing roller in which a part of an angle formed by the side surface of the convex portion and the bottom surface of the concave portion is an obtuse angle (bumping state). FIG. 4 is an enlarged cross-sectional view of the surface of the developing roller where a part of an angle formed by the side surface of the convex part and the bottom surface of the concave part is an obtuse angle (tip contact state). FIG. 4 is an enlarged view of the surface of a developing roller having a square top surface of a convex portion having a side perpendicular to the surface movement direction. Explanatory drawing of the contact state of the doctor blade with respect to a developing roller. (A) is explanatory drawing of the state which made the blade contact the tangent direction of a developing roller, (b) is explanatory drawing of the state which moved the blade folder from the state of (a) to the normal line direction, (c). These are explanatory drawings of the state which moved the blade folder in the tangential direction from the state of (b). The graph which shows the experimental result of Experiment 1. The enlarged explanatory view of the state of edge contact. The graph which shows the experimental result of Experiment 2. Graph comparing the amount of doctor blade shaving due to differences in materials. 6 is a flowchart of a notification system that notifies replacement of a developing device. FIG. 3 is an enlarged explanatory view of a doctor blade and a developing roller of a developing device whose replacement time is approaching. Explanatory drawing of the surface shape of the developing roller of Reference Configuration Example 1, (a) is a schematic diagram of the entire developing roller, (b) is an enlarged top view of region η in (a), (c) is (b) ) In FIG. Explanatory drawing of the surface shape of the developing roller of Reference Configuration Example 3, (a) is a schematic diagram of the entire developing roller, (b) is an enlarged top view of region η in (a), (c) is (b) ) In FIG. Explanatory drawing of the surface shape of the developing roller of Reference Configuration Example 4, (a) is a schematic diagram of the entire developing roller, (b) is an enlarged top view of region η in (a), (c) is (b) ) In FIG. Explanatory drawing of the surface shape of the developing roller of Comparative Example 1, (a) is a schematic diagram of the entire developing roller, (b) is an enlarged top view of region η in (a), (c) is (b) Sectional drawing of an EE 'cross section in the inside. FIG. 4 is a schematic cross-sectional view of a main part of a printer according to a second embodiment. FIG. 3 is an enlarged sectional view of one of four process cartridges provided in the printer. FIG. 3 is an enlarged cross-sectional view in the vicinity of an end portion in the axial direction of the process cartridge. Sectional drawing along the axial direction of the image development apparatus with which the process cartridge is provided.

Embodiment 1
Hereinafter, a first embodiment (hereinafter referred to as Embodiment 1) of the present invention in which the present invention is applied to a copying machine (hereinafter referred to as a copying machine 500) as an image forming apparatus will be described.
FIG. 2 is a schematic configuration diagram of the copying machine 500 according to the first embodiment. The copying machine 500 includes a copying machine main body (hereinafter referred to as a printer unit 100), a paper feed table (hereinafter referred to as a paper feed unit 200), and a scanner (hereinafter referred to as a scanner unit 300) mounted on the printer unit 100.

The printer unit 100 includes process cartridges 1 (Y, M, C, and K) as four process units, an intermediate transfer belt 7, an exposure device 6 as exposure means, a fixing device 12 as fixing means, and the like. The intermediate transfer belt 7 is an intermediate transfer member that is stretched by a plurality of stretching rollers and moves in the direction of arrow A in FIG.
The suffixes Y, M, C, and K attached to the four process cartridges 1 indicate the specifications for yellow, magenta, cyan, and black. The four process cartridges 1 (Y, M, C, and K) have substantially the same configuration except that the colors of the toners to be used are different, so the subscripts K, Y, M, and C are omitted below. I will explain.

  The process cartridge 1 is a unit that integrally supports a photosensitive member 2 as a latent image carrier, a charging member 3 as a charging unit, a developing device 4 as a developing unit, and a photosensitive member cleaning device 5 as a cleaning unit. The configuration is shaped like Each process cartridge 1 can be attached to and detached from the copying machine 500 main body by releasing a stopper (not shown).

  The photoconductor 2 rotates in the clockwise direction in the figure as indicated by the arrow in the figure. The charging member 3 is a roller-shaped charging roller, is in pressure contact with the surface of the photoconductor 2, and is rotated by the rotation of the photoconductor 2. At the time of image formation, a predetermined bias is applied to the charging member 3 by a high voltage power source (not shown) to charge the surface of the photoreceptor 2. In the process cartridge 1 of the first embodiment, the roller-shaped charging member 3 that contacts the surface of the photoreceptor 2 is used as the charging unit. However, the charging unit is not limited to this, and non-contact such as corona charging. A charging method may be used.

The exposure device 6 exposes the surface of the photoconductor 2 on the surface of the photoconductor 2 based on the image information of the original image read by the scanner unit 300 or image information input from an external device such as a personal computer. An electrostatic latent image is formed. The exposure device 6 provided in the printer unit 100 uses a laser beam scanner system using a laser diode, but may have other configurations such as an exposure unit using an LED array.
The photoconductor cleaning device 5 cleans the transfer residual toner remaining on the surface of the photoconductor 2 that has passed the position facing the intermediate transfer belt 7.

  The four process cartridges 1 form toner images for the respective colors of yellow, cyan, magenta, and black on the photoreceptor 2. The four process cartridges 1 are arranged in parallel in the surface movement direction of the intermediate transfer belt 7 and transfer the toner images formed on the respective photoreceptors 2 in order to be superimposed on the intermediate transfer belt 7 in order. A visible image is formed on the belt 7.

  In FIG. 2, a primary transfer roller 8 serving as a primary transfer unit is disposed at a position facing each photoconductor 2 with the intermediate transfer belt 7 interposed therebetween. A primary transfer bias is applied to the primary transfer roller 8 by a high voltage power source (not shown) to form a primary transfer electric field with the photosensitive member 2. By forming a primary transfer electric field between the photosensitive member 2 and the primary transfer roller 8, the toner image formed on the surface of the photosensitive member 2 is transferred to the surface of the intermediate transfer belt 7. One of a plurality of stretching rollers that stretch the intermediate transfer belt 7 is rotated by a drive motor (not shown), so that the intermediate transfer belt 7 moves in the direction of arrow A in the figure. A full color image is formed on the surface of the intermediate transfer belt 7 by sequentially transferring the toner images of the respective colors on the surface of the intermediate transfer belt 7 moving on the surface.

  A secondary transfer roller 9 is disposed on the downstream side of the surface of the intermediate transfer belt 7 with respect to the position where the four process cartridges 1 face the intermediate transfer belt 7. The secondary transfer roller 9 is disposed at a position facing the secondary transfer counter roller 9a, which is one of the stretching rollers, with the intermediate transfer belt 7 therebetween, and the secondary transfer nip between the secondary transfer roller 9 and the intermediate transfer belt 7 is provided. Form. A predetermined voltage is applied between the secondary transfer roller 9 and the secondary transfer counter roller 9a to form a secondary transfer electric field. The transfer paper P, which is a transfer material fed from the paper feed unit 200 and conveyed in the direction of arrow S in FIG. 2, passes through the secondary transfer nip. When the transfer paper P passes through the secondary transfer nip, a full color image formed on the surface of the intermediate transfer belt 7 is formed between the secondary transfer roller 9 and the secondary transfer counter roller 9a. It is transferred onto the transfer paper P by the next transfer electric field.

A fixing device 12 is disposed downstream of the secondary transfer nip in the conveyance direction of the transfer paper P. The transfer paper P that has passed through the secondary transfer nip reaches the fixing device 12. Then, the full-color image transferred onto the transfer paper P is fixed by heating and pressurization in the fixing device 12, and the transfer paper P on which the image is fixed is output outside the copying machine 500.
On the other hand, the toner remaining on the surface of the intermediate transfer belt 7 without being transferred to the transfer paper P at the secondary transfer nip is collected by the transfer belt cleaning device 11.

As shown in FIG. 2, above the intermediate transfer belt 7, toner bottles 400 (Y, M, C, K) that store toners of various colors are detachably disposed on the copying machine 500 main body.
The toner stored in each color toner bottle 400 is supplied to each color developing device 4 by a toner replenishing device (not shown) corresponding to each color.

FIG. 3 is a schematic diagram illustrating a schematic configuration of the developing device 4 according to the first embodiment, and is a cross-sectional view as viewed from the back side of the paper surface in FIG. 2.
4 and 5 are perspective explanatory views of the developing device 4, and are perspective explanatory views of the developing device 4 as viewed obliquely from above in different directions.
The developing casing 41 that forms the outer shape of the developing device 4 is formed by combining an upper case 411, an intermediate case 412, and a lower case 413. The middle case 412 forms a toner accommodating portion 43, and the upper case 411 is formed with a toner replenishing port 55 that is a developer replenishing portion that communicates the toner accommodating portion 43 with the outside. The upper case 411 is provided with an inlet seal 47 that seals a gap between the developing roller 42 and the upper case 411.

  6 is an explanatory cross-sectional view of the developing device 4 as viewed from the same direction as FIG. 3, and FIG. 7 is an enlarged perspective view of a part of the developing device 4, and a part thereof is a ZX sectional view. It is explanatory drawing shown.

The middle case 412 is provided with a developing roller 42, a supply roller 44, a doctor blade 45, a paddle 46, a supply screw 48, a remaining toner sensor 49, and the like.
The developing device 4 is provided with an opening 56 that communicates the inside and the outside along the longitudinal direction (Y-axis direction in the figure). A cylindrical developing roller 42 is provided in the opening 56 to carry and carry the toner from the inside to the outside (developing area α facing the photoconductor).
A remaining toner sensor 49 provided in the middle case 412 detects the amount of toner in the toner storage unit 43.

FIG. 8 is an enlarged perspective view of the vicinity of one end portion (the rear end portion in FIG. 2) of the developing device 4 in which the lower case 413 is omitted, and FIG. 9 shows the developing roller 42 from the state of FIG. FIG. 2 is an enlarged perspective view of the developing device 4 in which FIG.
FIG. 10 is an enlarged perspective view of the vicinity of the other end (the front side end in FIG. 2) of the developing device 4 in which the lower case 413 is omitted, and FIG. 11 shows the developing roller 42 from the state of FIG. FIG. 2 is an enlarged perspective view of the developing device 4 in which FIG.

  As shown in FIGS. 8 to 11, side seals 59 are attached to a part of the middle case 412 corresponding to both ends in the longitudinal direction of the opening 56 of the developing device 4. The side seal 59 is provided on the inner side in the axial direction with respect to the spacer 422 provided in the vicinity of both ends in the axial direction of the developing roller 42, and in a region where the axial end where the doctor blade 45 contacts the developing roller 42 overlaps. ing. Such a side seal 59 prevents the toner from leaking from the end portion in the longitudinal direction of the opening 56 in the developing casing 41. As will be described later, both ends of the developing roller shaft in the axial direction of the developing roller 42 are rotatably attached to the side wall portion 412s of the middle case 412.

In the developing device 4, the supply roller 44 rotates in the direction of arrow C in FIG. 3 (clockwise direction in FIG. 3) and moves on the surface, so that the toner T in the toner storage portion 43 faces the developing roller 42. Then, the toner is supplied to the surface of the developing roller 42. The developing roller 42 carries the supplied toner on the surface, rotates in the direction of arrow B in FIG. 3 (clockwise direction in FIG. 3), and moves on the surface, thereby removing the toner on the developing roller 42. The toner is conveyed to a portion facing the doctor blade 45 that is regulated to a predetermined amount. The doctor blade 45 is opposed to the developing roller 42, and is in a counter direction with respect to the surface movement direction of the developing roller 42 (the tip of the doctor blade 45 is upstream of the surface movement direction of the developing roller 42 with respect to the base of the doctor blade 45. Abut). The toner regulated to a predetermined amount at the portion facing the doctor blade 45 reaches the developing area α which is the portion facing the photoreceptor 2 by the rotation of the developing roller 42.
In the supply nip β, the surface of the supply roller 44 moves from below to above, and the surface of the developing roller 42 moves from above to below. In the developing device 4 of this embodiment, the supply roller 44 and the development roller 42 are in contact with each other at the supply nip β.

In the developing area α, the toner T on the surface of the developing roller 42 is generated according to the developing electric field formed by the potential difference between the developing bias applied from the developing bias power source 142 to the developing roller 42 and the latent image on the surface of the photoreceptor 2. Moves to the surface of the photoreceptor 2. As a result, the toner adheres to the electrostatic latent image portion on the surface of the photoreceptor 2 and development is performed. The photoreceptor 2 rotates in the direction of arrow D in FIG. 3 without contact with the developing roller 42. For this reason, in the development area α, the surface movement direction of the developing roller 42 and the surface movement direction of the photosensitive member 2 are the same direction.
The developing bias power source 142 is a voltage applying unit that applies an alternating voltage to the developing roller 42. The alternating voltage includes a first voltage for directing the toner from the developing roller 42 to the photosensitive member 2 for developing the latent image by the toner conveyed to the developing region α, and the toner from the photosensitive member 2 to the developing roller 42. And a second voltage for directing.

As will be described in detail later, the surface of the developing roller 42 has a regular uneven shape having a substantially constant height of the convex portion 42a and a depth of the concave portion 42b over the entire outer peripheral surface.
The toner T on the surface of the developing roller 42 that has not contributed to the development in the developing region α and has passed through the developing region α is collected by the supply roller 44 at the upstream side of the developing roller 42 in the surface movement direction in the supply nip β. The surface of the developing roller 42 is reset. That is, the supply roller 44 also has a role as a collection roller.

  The toner T carried in the concave portions 42b regularly formed on the surface of the developing roller 42 is difficult to be collected. Then, when the toner T that has passed through the developing region α passes through the supply nip β and remains carried on the developing roller 42, the toner T adheres to the developing roller 42 and toner filming occurs. When toner filming occurs, the charge amount per unit weight of the toner T on the developing roller 42 and the toner amount per unit area of the developing roller 42 become unstable, causing density unevenness during development.

In the developing device 4 of the first embodiment, the surface movement direction of the developing roller 42 and the surface movement direction of the supply roller 44 are opposite to each other in the supply nip β where the developing roller 42 and the supply roller 44 face each other. As a result, the linear velocity difference between the surface of the developing roller 42 and the surface of the supply roller 44 at the supply nip β increases, and the recovery performance of the supply roller 44 at the supply nip β can be improved. Therefore, it is possible to suppress the toner from being held on the developing roller 42, to suppress the toner from adhering to the surface of the developing roller 42, and to cause the developer to adhere to the surface of the developer carrying member. The occurrence of density unevenness during development can be suppressed.
Further, it is desirable that the linear velocity of the developing roller 42 is high. In the developing device 4 of the first embodiment, the linear speed ratio between the developing roller 42 and the supply roller 44 is “surface movement speed of the developing roller 42”: “surface movement speed of the supply roller 44” = 1: 0.85. However, the linear speed ratio is not limited to this value.

  Further, as shown in FIG. 3, in the developing device 4, the supply roller 44 is disposed above the toner storage portion 43, and at least a part of the supply roller 44 is in the toner storage portion 43 in a state where the rotation of the paddle 46 is stopped. The surface is above the surface of the toner T. An area downstream of the supply nip β with respect to the surface movement direction of the supply roller 44 (hereinafter referred to as a supply nip downstream area) is above the surface of the toner T. When the toner is filled in the downstream area of the supply nip as in the configuration shown in FIG. 4 of Patent Document 1, the toner filled in the downstream area of the supply nip is replaced with new toner in the downstream area of the supply nip. There is a risk of hindering entry. If the new toner is prevented from entering the downstream area of the supply nip, there is a risk that the efficiency of collecting the toner from the developing roller 42 in the supply nip β may be reduced.

  On the other hand, as shown in FIG. 3, in the developing device 4 of the first embodiment, the downstream area of the supply nip is above the surface of the toner T, and therefore the downstream area of the supply nip is not filled with toner. . Therefore, the toner present in the downstream area of the supply nip is not hindered from collecting the toner from the developing roller 42 in the supply nip β, and the toner can be collected efficiently and the toner can be reset. Can be improved.

Next, the developing roller 42 will be described.
FIG. 12 is an explanatory perspective view of the developing roller 42, and FIG. 13 is a side view of the developing roller 42. FIG. 1 is an explanatory diagram of the surface shape of the developing roller 42 according to the first embodiment. 1A is a schematic view of the entire developing roller 42, FIG. 1B is an enlarged top view of a region η in FIG. 1A, and FIG. 1C is FIG. It is sectional drawing of an inside EE 'cross section.

The developing roller 42 has a configuration in which a developing roller cylindrical portion 420 that carries toner on the surface thereof is provided on the developing roller shaft 421, and the developing roller shafts in the vicinity of both axial end portions that are axially outside the developing roller cylindrical portion 420. A spacer 422 is provided at 421.
The developing roller 42 is provided so as to be rotatable about the developing roller shaft 421, and is arranged so that the axial direction of the developing roller shaft 421 is parallel to the longitudinal direction (Y-axis direction in the drawing) of the developing device 4. Yes. Both ends of the developing roller shaft 421 in the axial direction of the developing roller 42 are rotatably attached to the side wall portion 412s of the middle case 412. A part of the surface of the developing roller 42 is exposed to the outside of the developing device 4 from the opening 56, and the developing roller 42 is moved from the lower side to the upper side to convey the toner so that the toner is conveyed in FIG. 3. It rotates in the direction of arrow B.
Further, in the developing roller 42, the distance between the surface of the developing roller cylindrical portion 420 and the surface of the photosensitive member 2 in the developing region α is obtained by the spacers 422 provided in the vicinity of both ends in the axial direction contacting the surface of the photosensitive member 2. (Development gap) is kept constant.

The developing roller 42 includes a base material 42g and a surface layer 42f formed on the outer peripheral surface of the base material 42g (see FIG. 31). The base 42g is made of a metal material sleeve such as an aluminum-based material such as 5056 aluminum alloy or 6063 aluminum alloy, or an iron-based material such as STKM.
The developing roller 42 is provided with a concavo-convex process on the surface of the metal sleeve that is the base material 42g, and nickel plating is applied to the metal material sleeve subjected to the concavo-convex process, thereby preventing corrosion of the developing roller 42, A surface layer 42f for assisting charging of the toner is formed.

As shown in FIG. 1A, the developing roller cylindrical portion 420 of the developing roller 42 is mainly divided into two portions (a concavo-convex forming portion 420a and a non-concave / convex forming portion 420b) based on the difference in the structure of the surface thereof. .
The concavo-convex forming portion 420a is a portion including the central portion in the axial direction of the developing roller 42, and concavo-convex processing is applied to the surface thereof in order to properly carry the toner. In the first embodiment, so-called rolling processing is used as the uneven processing on the surface of the developing roller 42. As the rolling process, a conventionally known processing method can be employed.

As shown in FIG. 1B, on the surface of the developing roller 42, an elliptic frustum-shaped convex portion 42a having a major axis in the surface movement direction of the developing roller 42 is formed with a pitch width W1 in the axial direction. The convex portion 42a has a top surface axial direction length W2a and a top surface moving direction length W2b (W2b> W2a).
In the developing roller 42 of the first embodiment, the pitch width W1 in the axial direction of the convex portion 42a is 80 [μm], and the length W2a in the top surface axial direction of the convex portion 42a is 40 [μm]. Furthermore, the recess depth W3, which is the height from the bottom surface 42h of the recess 42b to the top surface 42t of the protrusion 42a, is 10 [μm]. The values of the pitch width W1, the top surface axial length W2a, and the recess depth W3 are merely examples, and are not limited to these values.

  As for the developing roller 42, it is desirable that the surface layer 42f is made of a material that normally charges the toner. Even when the low-charged toner is produced by the filming, the low-charged toner knocked out by the jumped toner T can be charged at the portions where the convex portions 42a and the concave portions 42b are not filmed. For this reason, low-charge toner can be reduced, and the image density is stabilized. In the developing roller 42 of the first embodiment, the surface layer 42f is a material that normally charges the toner by applying nickel plating.

  Further, it is desirable that the surface material of the developing roller 42 is harder than the doctor blade 45 (blade member 450). This makes it difficult for the convex portion 42a on the surface of the developing roller 42 to be scraped by the doctor blade 45, so that the volume of the concave portion 42b surrounded by the convex portion 42a and the doctor blade 45 is difficult to change, and the M / A value (on the surface of the developing roller) The amount of toner carried per unit area) is stabilized.

  The height of the convex portion 42a of the developing roller 42 is desirably larger than the weight average particle diameter of the toner T to be used. Since the toner T having an average size is accommodated in the recess 42b, the selection of the particle size is difficult to occur, and the M / A value (the amount of toner carried per unit area on the surface of the developing roller) is stabilized over time. .

Next, the supply roller 44 will be described.
FIG. 14 is an explanatory perspective view of the supply roller 44, and FIG. 15 is a side view of the supply roller 44. A cylindrical supply roller 44 is provided on the developing roller 42 side above the toner container 43 inside the developing device 4. The supply roller 44 has a configuration in which a cylindrical foam material is wound around a supply roller shaft 441 that is a shaft portion thereof, and the cylindrical foam material becomes a supply roller cylindrical portion 440 that carries toner on the surface thereof. .

The supply roller 44 is configured to be rotatable about a supply roller shaft 441, and the shaft is attached to the side wall portion 412 s of the middle case 412 so as to be rotatable. The supply roller 44 is arranged such that a part of the outer peripheral surface of the supply roller cylindrical portion 440 is in contact with the outer peripheral surface of the developing roller cylindrical portion 420 of the developing roller 42 at the supply nip β. As shown, the supply roller shaft 441 is disposed above the developing roller shaft 421.
Further, as described above, the supply roller 44 rotates so that the surface moves in the direction opposite to the surface movement direction of the developing roller 42 at the supply nip β that is a portion facing the developing roller 42. Further, as shown in FIG. 3, the developing device 4 is arranged such that the position of the supply nip β is positioned above the contact position of the doctor blade 45 with respect to the developing roller 42.

  A foam material is used for the supply roller cylindrical portion 440 of the supply roller 44, and the surface layer in contact with the developing roller 42 is a sponge layer in which a large number of micropores are dispersed on the surface. By making the surface layer of the supply roller 44 into a sponge shape, the supply roller 44 can easily reach the bottom of the recess 42b, so that the resetability of the toner on the developing roller 42 is improved.

  Further, the amount of biting of the supply roller 44 with respect to the development roller 42 (“radius of the development roller 42” + “radius of the supply roller 44” − “distance between the axes of the development roller 42 and the supply roller 44”) The height is set to be larger than the height (W3) of the convex portion 42a. By making the amount of biting of the supply roller 44 larger than the height of the convex portion 42a, the toner resetting property in the concave portion 42b can be improved. Note that if the amount of biting of the supply roller 44 with respect to the developing roller 42 is too large relative to the height of the convex portion 42a, the toner will be pushed into the concave portion 42b and cause aggregation, so the amount of biting will not be too large. It is necessary to set as follows.

The foam material used for the supply roller cylindrical portion 440 of the supply roller 44 is set to an electric resistance value of 10 ³ to 10 ¹⁴ [Ω].
A supply bias is applied to the supply roller 44 by a supply bias power supply 144 to assist the operation of pressing the toner preliminarily charged at the supply nip β against the developing roller 42. The supply roller 44 rotates in the clockwise direction in FIGS. 3 and 6 to apply and supply the developer adhered on the surface to the surface of the developing roller 42.

  The voltage applied to the supply roller 44 by the supply bias power supply 144 is opposite to the normal charging polarity of the toner (negative polarity in the toner T of the first embodiment) with respect to the alternating voltage applied to the developing roller 42. Apply polarity (positive polarity) DC voltage. At this time, the voltage applied to the supply roller 44 is opposite in polarity (plus polarity) to the normal charging polarity of the toner than the voltage applied to the developing roller 42. As a result, an electric field in the direction in which the toner T is attracted toward the supply roller 44 with respect to the development roller 42 is formed in the supply nip β, and the resetability of the toner on the development roller 42 can be improved. Note that the configuration including the supply bias power supply 144 requires a separate DC power supply, which increases the cost. Therefore, the supply bias power supply 144 may not be provided according to the specifications of the developing device 4.

Next, the doctor blade 45 will be described.
FIG. 16 is an explanatory perspective view of the doctor blade 45, and FIG. 17 is a side view of the doctor blade 45.
As shown in FIGS. 6 to 11, a doctor blade 45 is provided in the middle case 412 that is below the developing roller 42 and is inside the lower case 413.
The doctor blade 45 includes a blade member 450 that is a thin plate-like metal member that constitutes a regulating member, and a metal base portion 452 to which one end of the blade member 450 is fixed. The other end side of the blade member 450 is configured to come into contact with the developing roller 42. The contact state of the blade member 450 with respect to the developing roller 42 may be any of a tip contact state in which the tip contacts (edge contact described later) and a stomach contact state in which a surface portion on the base side from the tip contacts. However, in the state where the tip is applied, the toner present on the top surface 42t of the convex portion 42a can be worn out, and only the toner present in the concave portion 42b is transported to the developing region α to be transported to the developing region α. This is more preferable because the toner amount is stable.

  The blade member 450 of the doctor blade 45 is fixed to the pedestal portion 452 by a plurality of rivets 451. The pedestal portion 452 is made of a metal that is thicker than the blade member 450 and functions as a substrate for fixing the blade member 450 to the main body of the developing device 4 (side surface portion of the middle case 412). A pin hole 454 is provided at the longitudinal end of the pedestal portion 452, one is a perfect circular main reference hole 454 a, and the other is an elliptical secondary reference hole having a long diameter in the direction of the main reference hole 454 a. 454b. When a pin (not shown) enters the main reference hole 454a, the position of the pedestal portion 452 with respect to the main body of the developing device 4 is determined and supported by the sub reference hole 454b. The pedestal portion 452 to which the blade member 450 is fixed is fixed to the developing device 4 main body (inner case 412) with a doctor fixing screw 455, whereby the blade member 450 is fixed to the developing device 4.

  For the blade member 450 of the doctor blade 45, a metal plate spring material such as SUS304CSP, SUS301CSP, or phosphor bronze is used. The blade member 450 is a member whose free end is brought into contact with the surface of the developing roller 42 with a pressing force of 10 to 100 [N / m], and the toner passing under the pressing force is restricted to a predetermined amount. At the same time, a charge is applied by triboelectric charging. Further, a bias may be applied to the blade member 450 from a doctor bias power source 145 in order to assist frictional charging.

  Further, the blade member 450 of the doctor blade 45 is desirably conductive. Since the blade member 450 is conductive, the charge amount of the toner T having a large Q / M value (charge amount per unit volume) can be lowered, and the Q / M value of the toner T can be made uniform. it can. Thereby, sticking of the toner T to the developing roller 42 can be prevented.

  The voltage applied by the doctor bias power supply 145 to the blade member 450 may be configured such that the value of the DC voltage can be controlled depending on the use environment. Specifically, a configuration in which a DC voltage can be applied in a range of ± 200 [V] with respect to the alternating voltage applied to the developing roller 42 can be mentioned. Thereby, it is possible to suppress fluctuations in the M / A value (toner carrying amount per unit area on the surface of the developing roller) due to environmental fluctuations.

Next, the paddle 46 will be described.
18 is a perspective explanatory view of the paddle 46, and FIG. 19 is a side view of the paddle 46. As shown in FIG.
A toner accommodating portion 43 is provided in the developing device 4 as a space for accommodating toner, and a paddle 46 is rotatably attached to the developing casing 41 in the toner accommodating portion 43.

The paddle 46 includes a paddle shaft 461 that is a shaft portion thereof, and paddle blades 460 as thin blade members made of an elastic sheet material such as Mylar. The paddle shaft 461 has two flat portions facing each other, and paddle blades 460 are respectively attached to the two flat portions. The two paddle blades 460 are fixed to the flat portion of the paddle shaft 461 so as to protrude in opposite directions around the paddle shaft 461.
The base portion of the paddle blade 460 is provided with a plurality of holes arranged in parallel so as to be parallel to the axial direction of the paddle shaft 461. The paddle shaft 461 has two rows of convex portions along the axial direction. Are arranged side by side. Then, the paddle blades 460 are fixed to the paddle shafts 461 by inserting the convex portions of the paddle shafts 461 into the holes of the paddle blades 460 and performing heat caulking.

  The paddle 46 is disposed so that the axial direction of the paddle shaft 461 is parallel to the longitudinal direction of the developing device 4 (Y-axis direction in the figure). Both ends in the axial direction of the paddle shaft 461 are rotatably attached to the side wall portion 412s of the middle case 412.

In the paddle 46, the protruding amount of the paddle blade 460 is set to such a length that the tip of the paddle blade 460 extending from the paddle shaft 461 contacts the inner wall surface of the toner containing portion 43. As shown in FIGS. 3 and 6, the bottom surface portion 43 b of the toner accommodating portion 43 has an arc shape along the rotation direction of the paddle 46, and the paddle blade 460 is moved by the rubbing operation accompanying the rotation of the paddle 46. 43 is prevented from being caught by the bottom surface portion 43b.
On the developing roller 42 side of the toner containing portion 43, a side wall surface portion 43s that rises vertically from the bottom surface portion 43b is formed. The side wall surface portion 43 s is horizontal in the direction toward the roller parallel to the X axis at a level that is equal to or slightly lower than the center of the paddle shaft 461, and forms a stepped portion 50.

  The distance between the side wall surface portion 43s and the paddle shaft 461 is set shorter than the distance between the bottom surface portion 43b and the paddle shaft 461. Therefore, the paddle blade 460 that has rubbed the bottom surface portion 43b hits the side wall surface portion 43s and bends more greatly. Thereafter, when the tip of the paddle wing 460 reaches the stepped portion 50, there is nothing to hold the paddle wing 460, and the tip of the paddle wing 460 is released and jumps upward. By such movement of the paddle blade 460, the toner is splashed upward, and is stirred, conveyed, and supplied.

  The step portion 50 is a horizontal plane parallel to the XY plane, and is formed to extend in the longitudinal direction of the developing device 4 (Y-axis direction in the drawing). In the developing device 4 of the first embodiment, the step portion 50 is provided in the entire region in the width direction, but may be provided in a part of the developing device 4 as long as the paddle blades 460 jump up.

  The supply screw 48 is a screw member that includes a supply screw shaft 481 and a supply screw blade portion 480 that is a spiral blade portion fixed to the supply screw shaft 481. The supply screw shaft 481 is provided so as to be rotatable, and the axial direction of the supply screw shaft 481 is arranged so as to be parallel to the longitudinal direction of the developing device 4 (Y-axis direction in the drawing). Both axial ends of the supply screw shaft 481 are rotatably attached to the side wall portion 412s of the middle case 412.

  The end of the supply screw 48 in the axial direction is positioned below a toner supply port 55 formed at the end of the developing device 4 in the longitudinal direction. Then, when the supply screw 48 is rotated, the spiral supply screw blade 480 conveys the toner replenished from the toner replenishing port 55 toward the central portion of the developing device 4 in the longitudinal direction.

  A sheet member such as Mylar is attached as an inlet seal 47 along the longitudinal direction to the edge portion forming the opening 56 of the upper case 411. The inlet seal 47 is a substantially rectangular sheet, one end of which is affixed to the edge portion of the upper case 411, and the other end is a free end. The free end side of the inlet seal 47 protrudes toward the inside of the developing device 4, and is further provided so as to contact the developing roller 42. The inlet seal 47 is fixed to the upper case 411 on the upstream side in the surface movement direction of the developing roller 42, and the downstream side in the surface movement direction of the developing roller 42 is a free end. Are arranged so that they touch each other. Further, the inner side of the developing device 4 of the upper case 411 is curved so as to follow the upper shape of the supply roller 44, and the gap between the curved surface of the upper case 411 and the surface of the supply roller 44 is 1 0.0 [mm].

Next, the movement of toner in the developing device 4 will be described.
The toner replenished into the developing device 4 from the toner replenishing port 55 is supplied to the toner accommodating portion 43 by the supply screw 48 and stirred by the paddle 46. Further, the paddle 46 is flipped up in the direction of the developing roller 42 and the supply roller 44 and conveyed. The toner supplied to the supply roller 44 is delivered to the surface of the developing roller 42 at a supply nip β where the supply roller 44 contacts the developing roller 42. Of the toner delivered to the surface of the developing roller 42, the amount of toner exceeding a predetermined amount conveyed to the developing area α is scraped off from the surface of the developing roller 42 by the doctor blade 45.

  The toner remaining on the surface of the developing roller 42 that has passed through the portion facing the doctor blade 45 is conveyed as it is by the surface movement caused by the rotation of the developing roller 42 and reaches the developing region α facing the photoreceptor 2. The toner that has passed through the development region α without being used for development passes through a position where the inlet seal 47 contacts, and is conveyed to the supply nip β that is a position facing the supply roller 44. The toner that has reached the supply nip β by the developing roller 42 is scraped off from the surface of the developing roller 42 by the supply roller 44 and conveyed by the supply roller 44.

  Next, toner used in the copier 500 according to the first embodiment will be described. As the toner used in the copying machine 500, a toner having high fluidity is used so as to be compatible with high-speed toner conveyance. Specifically, a toner having an accelerated aggregation degree of 40% or less is used. The accelerated aggregation degree is an index indicating the fluidity of the toner.

A method for measuring the accelerated aggregation degree of the toner is shown below.
<Measurement device>
・ Powder tester made by Hosokawa Micron <Measurement method>
・ Leave the sample to be measured in a thermostat (35 ± 2 [° C], 24 ± 1 [h])
・ Measured with a powder tester ・ Three types of sieves with different openings (for example, 75 [μm], 44 [μm], 22 [μm])
-Calculate from the remaining amount of toner when sieving, and obtain the degree of aggregation by the following calculation.
{(Weight of toner remaining on upper screen) / (sample amount)} × 100
{(Weight of toner remaining on middle screen) / (sample amount)} × 100 × 3/5
{(Weight of toner remaining on lower screen) / (sample amount)} × 100 × 1/5
The total of the above three calculated values is defined as the heat aggregation degree [%].

  As described above, the accelerated aggregation degree of the toner is an index obtained by stacking three types of meshes having different openings in the order of increasing openings, placing particles on the uppermost stage, sieving with constant vibration, and calculating from the toner weight on each mesh. .

In the first exemplary embodiment, toner having an average circularity of 0.90 or more (0.90 to 1.00 toner) is used.
In Embodiment 1, the value obtained from the following equation (1) is defined as circularity a. This circularity is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.

Circularity a = L ₀ / L (1)
(L ₀ : circumference of a circle having the same projected area as the particle image, L: circumference of the projected image of the particle)

When the average circularity is in the range of 0.90 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photoreceptor 2 is small, so that the transferability is excellent.
When the average circularity is in the range of 0.90 to 1.00, since the toner particles have no corners, the developer (toner) agitation torque in the developing device 4 is small, and the agitation drive is stabilized. Can be prevented.
In addition, since there are no angular toner particles in the toner that forms the dots, when the pressure is brought into contact with the transfer medium during transfer, the pressure is uniformly applied to the entire toner that forms the dots, and the transfer is not easily lost.
Further, since the toner particles are not angular, the abrasive power of the toner particles itself is small, and it is possible to prevent the surfaces of the photoreceptor 2 and the charging member 3 from being damaged or worn.

  Next, a method for measuring the circularity will be described. The circularity can be measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics.

  As a specific measuring method, a surfactant, preferably an alkylbenzene sulfonate, is added in an amount of 0.1 to 0.5 [100] as a dispersant in 100 to 150 [ml] of water from which impure solids have been removed in advance. ml] and about 0.1 to 0.5 [g] of a measurement sample is further added. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and particle size of the toner are measured with the above apparatus with the dispersion concentration being 3000 to 10,000 [pieces / μl].

  In order to reproduce minute dots of 600 [dpi] or more, the weight average particle diameter (D4) of the toner is preferably 3 to 8 [μm]. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent. When the weight average particle diameter (D4) is less than 3 [μm], phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur.

  When the weight average particle diameter (D4) exceeds 8 [μm], it is difficult to suppress scattering of characters and lines. Moreover, it is preferable that ratio (D4 / D1) of a weight average particle diameter (D4) and a number average particle diameter (D1) exists in the range of 1.00-1.40. The closer (D4 / D1) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

  Next, a method for measuring the particle size distribution of toner particles will be described. Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.

  First, 0.1 to 5 [ml] of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 [ml] of the electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 [mg] of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the weight and number of toner particles or toner using a 100 [μm] aperture as the aperture. Then, the weight distribution and the number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.

  As a channel, it is less than 2.00-2.52 [micrometer]; 2.52-less than 3.17 [micrometer]; 3.17-less than 4.00 [micrometer]; 4.00-5.04 [micrometer] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], particles having a particle size of 2.00 [μm] or more to less than 40.30 [μm] are targeted.

  The toner used in Embodiment 1 uses a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. The toner used in Embodiment 1 is a toner obtained by crosslinking and / or extending the toner material liquid in an aqueous solvent, and is called a polymerization toner. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

<Polyester>
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound. Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
The polycondensation reaction of polyhydric alcohol (PO) and polycarboxylic acid (PC) is heated to 150 to 280 [° C.] in the presence of a known esterification catalyst such as tetrabutoxy titanate or dibutyltin oxide. And the water produced | generated while reducing pressure if necessary is distilled off, and the polyester which has a hydroxyl group is obtained. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively chargeable, and further, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.
The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. With respect to this urea-modified polyester, the terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction is reacted with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. The urea-modified polyester is obtained by crosslinking and / or extending the molecular chain by the reaction between the polyester prepolymer (A) and amines.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is the equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. At this time, the equivalent ratio [NCO] / [OH] is usually 5/1 to 1/1, preferably 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. is there. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyisocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 [wt%], preferably 1 to 30 [wt%], more preferably 2 to 20 [wt%]. If it is less than 0.5 [wt%], the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 [wt%], the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, examples of the amines (B) to be reacted with the polyester prepolymer (A) include a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), and an amino alcohol (B3). Furthermore, examples of the amines (B) include aminomercaptan (B4), amino acid (B5), and amino acids B1 to B5 blocked (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.). Examples of the divalent amine compound (B1) also include alicyclic diamines (such as 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diaminecyclohexane, and isophoronediamine). Further, examples of the divalent amine compound (B1) include aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.).

  Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.

  Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of B1 to B5 blocked amino groups (B6) include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  Regarding the ratio of amines (B), the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B) And At this time, the equivalent ratio [NCO] / [NHx] is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1/1. 2.

  When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated. The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyhydric carboxylic acid (PC) are produced in the presence of a known esterification catalyst such as tetrabutoxy titanate and dibutyltin oxide at 150 to 280 [° C.] and, if necessary, reduced pressure. Water is distilled off to obtain a polyester having a hydroxyl group. Next, at 40 to 140 [° C.], this is reacted with polyvalent isocyanate (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. Further, this (A) is reacted with amines (B) at 0 to 140 [° C.] to obtain a urea-modified polyester.

  When reacting the polyvalent isocyanate compound (PIC) and when reacting (A) and (B), a solvent may be used as necessary. Examples of usable solvents include aromatic solvents (toluene, xylene, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) and the like. Examples of the solvent include esters (such as ethyl acetate), amides (such as dimethylformamide and dimethylacetamide), and ethers (such as tetrahydrofuran). Examples of the solvent include those inert to the polyvalent isocyanate compound (PIC).

  In addition, in the crosslinking and / or elongation reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator may be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the copying machine 500 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5 [%], the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 [° C.], preferably 45 to 60 [° C.]. If the temperature is less than 45 [° C.], the heat resistance of the toner deteriorates, and if it exceeds 65 [° C.], the low-temperature fixability becomes insufficient.

  In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

<Colorant>
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% [%], preferably 3 to 10% [%] based on the toner.

  The colorant can also be used as a master batch combined with a resin. Examples of the binder resin that is kneaded together with the production of the master batch or the master batch include styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyl toluene, and polymers of substituted products thereof. Examples of the binder resin include a copolymer of styrene and its substituted polymer and a vinyl compound. Furthermore, examples of the binder resin include polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, and polyester. Examples of the binder resin include epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, and terpene resin. Furthermore, examples of the binder resin include aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin, and paraffin wax. These binder resins can be used alone or in combination.

<Charge control agent>
Known charge control agents can be used, and examples include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, and alkoxy amines. Examples of the charge control agent include quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, and the like. Furthermore, examples of the charge control agent include a fluorine-based activator, a salicylic acid metal salt, and a metal salt of a salicylic acid derivative.

  Specific examples include bontron 03 of a nigrosine dye, bontron P-51 of a quaternary ammonium salt, bontron S-34 of a metal-containing azo dye, and E-82 of an oxynaphthoic acid metal complex. In addition, E-84 of salicylic acid metal complex, E-89 of phenol-based condensate (above, manufactured by Orient Chemical Industries), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, Hodogaya Chemical Co., Ltd.) Etc.). Further, a quaternary ammonium salt copy charge PSY VP2038, a triphenylmethane derivative copy blue PR (manufactured by Hoechst), and the like can be mentioned. Further, copy charge NEG VP2036 of quaternary ammonium salt, copy charge NX VP434 (manufactured by Hoechst Co., Ltd.) and the like can also be mentioned. Moreover, LRA-901, LR-147 (made by Nippon Carlit Co., Ltd.) which is a boron complex, copper phthalocyanine, perylene, quinacridone, an azo pigment, etc. can be mentioned. Furthermore, other high molecular compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts are listed. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller 42 is increased, the developer fluidity is reduced, and the image density is reduced. Incurs a decline.

<Release agent>
As the release agent, a low melting point wax having a melting point of 50 to 120 [° C.] is more effectively used as a release agent in the dispersion with the binder resin between the fixing roller of the fixing device 12 and the toner interface. work. As a result, it is effective against high temperature offset without applying a release agent such as oil to the fixing roller. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax, animal waxes such as beeswax and lanolin, and mineral waxes such as ozokerite and cercin. Furthermore, petroleum waxes such as paraffin, microcrystalline, and petrolatum are listed. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used.

  Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, and chlorinated hydrocarbons are exemplified. Moreover, poly-n-stearyl methacrylate, poly-n-lauryl methacrylate and the like, which are low molecular weight crystalline polymer resins, can be mentioned. Crystalline polymers having a long alkyl group in the side chain such as homopolymers or copolymers of these polyacrylates (for example, copolymers of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used.

  The charge control agent and the release agent can be melt-kneaded together with the masterbatch and the binder resin, or may be added when dissolved and dispersed in an organic solvent.

<External additive>
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ⁻³ to 2 [μm], particularly preferably 5 × 10 ^{−3 to} 0.5 [μm]. Moreover, it is preferable that the specific surface area by BET method is 20-500 [m < ² > / g]. The use ratio of the inorganic fine particles is preferably 0.01 to 5 [wt%] of the toner, and particularly preferably 0.01 to 2.0 [wt%].

Specific examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide and tin oxide. Also, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. Can be mentioned. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. Particularly when both the fine particles have an average particle size of 5 × 10 ⁻² [μm] or less and are stirred and mixed, electrostatic force and van der Waals force with the toner are remarkably improved. As a result, even when the developing device 4 is stirred and mixed in order to obtain a desired charge level, the fluidity-imparting agent is not detached from the toner, and a good image quality that does not generate fireflies can be obtained. Further, transfer residual toner can be reduced.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large.

  However, when the addition amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 [wt%], the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained. Even if copying is repeated, stable image quality can be obtained.

  Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

<Toner production method>
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent. The organic solvent is preferably volatile with a boiling point of less than 100 [° C.] from the viewpoint of easy removal after toner base particle formation. Specific examples include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, and the like. Monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and the like can also be mentioned. These can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

  (2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles. The aqueous medium may be water alone or may contain an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.) or dimethylformamide. Examples of the organic solvent contained in the aqueous medium include tetrahydrofuran, cellosolves (such as methyl cellosolve), and lower ketones (such as acetone and methyl ethyl ketone).

  The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

  Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonate, α-olefin sulfonate, and phosphate ester. Further, amine salt type cationic surfactants such as alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives and imidazolines can also be mentioned. Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt and benzethonium chloride can also be mentioned. Furthermore, nonionic surfactants, such as a fatty acid amide derivative and a polyhydric alcohol derivative, can also be mentioned. In addition, examples include amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine, and N-alkyl-N, N-dimethylammonium betaine.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred examples of the anionic surfactant having a fluoroalkyl group include C2-C10 fluoroalkylcarboxylic acids and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, and the like. In addition, sodium 3- [ω-fluoroalkyl (C6-C11) oxy] -1-alkyl (C3-C4) sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1- And sodium propanesulfonate. Moreover, fluoroalkyl (C11-C20) carboxylic acid and its metal salt, perfluoroalkyl carboxylic acid (C7-C13), its metal salt, etc. are mentioned. Moreover, perfluoroalkyl (C4-C12) sulfonic acid and its metal salt are mentioned. Moreover, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, and the like can be given. Furthermore, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate and the like can be mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.) and the like. In addition, MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink Co., Ltd.) and the like can be mentioned. Further, Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fategent F-100, F150 (manufactured by Neos), etc. Can be mentioned.

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt can be mentioned. Moreover, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, and the like can be given. Examples of product names include Surflon S-121 (manufactured by Asahi Glass Co., Ltd.), Florard FC-135 (manufactured by Sumitomo 3M Company), Unidyne DS-202 (manufactured by Daikin Industries Co., Ltd.), and the like. Furthermore, MegaFuck F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos) are listed.

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage which exists on the surface of a toner base particle becomes the range of 10-90 [%]. Examples thereof include polymethyl methacrylate fine particles 1 [μm] and 3 [μm], polystyrene fine particles 0.5 [μm] and 2 [μm], poly (styrene-acrylonitrile) fine particles 1 [μm], and the like. In terms of product names, PB-200H (manufactured by Kao Corporation), SGP (manufactured by Sokensha), technopolymer SB (manufactured by Sekisui Plastics Co., Ltd.), SGP-3G (manufactured by Sokensha), micropearl (manufactured by Sekisui Fine Chemical), etc. There is.

  In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups The body can be mentioned. For example, acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxypropyl Etc. Moreover, acrylic acid-3-chloro 2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylic acid ester, diethylene glycol monomethacrylic acid ester, glycerin monoacrylic acid ester and the like can be mentioned. Moreover, glycerol monomethacrylic acid ester, N-methylol acrylamide, N-methylol methacrylamide, etc. are mentioned. Furthermore, vinyl alcohol or ethers with vinyl alcohol such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether and the like can be mentioned. Or the ester of the compound containing a vinyl alcohol and a carboxyl group, for example, vinyl acetate, vinyl propionate, vinyl butyrate, etc. are mentioned. Moreover, acrylamide, methacrylamide, diacetone acrylamide, or these methylol compounds, acid chlorides, such as acrylic acid chloride and methacrylic acid chloride, etc. are mentioned. Furthermore, homopolymers or copolymers such as nitrogen-containing compounds such as vinylpyridine, vinylpyrrolidone, vinylimidazole, and ethyleneimine, or those having a heterocyclic ring thereof may be mentioned. In addition, polyoxyethylene-based compounds such as polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide and the like can be mentioned. Further, polyoxyethylene-based compounds such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester, and the like can be mentioned. In addition, celluloses such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, in order to make the particle size of the dispersion 2 to 20 [μm], a high-speed shearing method is preferable. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 [rpm], preferably 5000 to 20000 [rpm]. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 [minutes]. The temperature during dispersion is usually 0 to 150 [° C.] (under pressure), preferably 40 to 98 [° C.].

  (3) At the same time as the preparation of the emulsion, the amines (B) are added to react with the polyester prepolymer (A) having an isocyanate group. This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 [° C.], preferably 40 to 98 [° C.]. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

  (4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles. In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent-based toner base particles can be produced by removing the solvent. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

  (5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner. The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

  As described above, on the surface of the developing roller 42 provided in the developing device 4 of Embodiment 1, irregularities having a regular pattern in which the height of the convex portion and the depth (W3) of the concave portion are constant are formed. . As a conventional one-component developing device, there is one in which a rough surface process such as a sound blast process is performed on the surface of a developing roller to form an uneven shape on the surface. As described above, the surface of the developing roller is roughened to improve the performance of the developing roller carrying and transporting toner. However, the unevenness formed on the surface of the developing roller by the rough surface treatment has irregularities in the height of the protrusions, the depth of the recesses, and the pattern of the unevenness. If the pattern and depth of the recesses are irregular, the toner carrying amount on the surface of the developing roller is not stable, and density unevenness may occur when the latent image on the photoreceptor is developed. On the other hand, in the developing device 4 of the first embodiment, since the depth (W3) of the concave portion is constant and the formation pattern is regular, the toner carrying amount on the surface of the developing roller 42 is stable, and density unevenness during development is obtained. Can be suppressed.

Here, the regular unevenness is sufficient as long as the unevenness is suppressed to the extent that density unevenness is suppressed without unevenness of the toner adhesion amount.
Further, for example, paying attention to the latent image on the photosensitive member 2, the latent image has a dot-like latent image formed in a region partitioned in a lattice shape, and the lattice can be formed at a plurality of pitches in the axial direction. It is. And what the pitch in the axial direction of a back | inner part is shorter than the longest pitch among several types of pitches in the said grating | lattice may be sufficient.
In addition, the present invention can be effective even if the uneven shape on the surface of the developing roller 42 is other than regular unevenness, but if it has regular unevenness, the image quality will be reduced. To preferred.

  As shown in FIGS. 3 and 20, in the developing device 4 of the first embodiment, the developing roller 42 in which the arrow B direction in the drawing is the rotational direction moves downward from above in the doctor portion. In such a case, since the downward force (Fg) is applied to the toner by its own weight acting on the toner T, the compressive force on the toner due to the stress (Fb) of the doctor blade 45 can be reduced. Therefore, it is possible to suppress the toner from aggregating at a portion (a portion 42c in FIG. 20) of the convex portion 42a of the developing roller 42 on the downstream side in the surface movement direction of the developing roller 42. As a result, the occurrence of filming can be suppressed, and fluctuations in the Q / M value and M / A value on the developing roller 42 can be suppressed.

  Further, as the toner that is a developer used in the developing device 4, it is desirable to use a toner having an accelerated aggregation degree of 40% or less. Thereby, it is possible to further alleviate the toner aggregation in the downstream portion (the portion 42c in FIG. 20) of the convex portion 42a of the developing roller 42 in the surface movement direction of the developing roller 42. In the doctor section shown in FIG. 20, the doctor blade 45 is placed against the surface of the developing roller 42. As shown in FIG. 21, the contact state of the doctor blade 45 with the surface of the developing roller 42 can be used to scrape off the toner T present on the top surface 42t of the convex portion 42a. More preferred.

As shown in FIG. 22, when the angle γ formed between the side surface of the convex portion 42a of the developing roller 42 and the bottom surface of the concave portion 42b is less than 90 °, the probability that the supply roller 44 contacts the entire concave portion 42b decreases. Resulting in. Also, as shown in FIG. 23, even when the angle formed by the side surface of the convex portion 42a and the bottom surface of the concave portion 42b is less than 90 [°], the probability that the supply roller 44 contacts the entire concave portion 42b is reduced. End up.
On the other hand, as shown in FIG. 24, the developing roller 42 included in the developing device 4 of Embodiment 1 has an angle γ formed by the side surface of the convex portion 42a of the developing roller 42 and the bottom surface of the concave portion 42b of 90 [°]. That's it. As shown in FIG. 24, when the angle γ is 90 [°] or more, the probability that the supply roller 44 hits the toner on the developing roller 42 increases, so that the resetting property is improved.

FIG. 25 is an explanatory diagram of a configuration in which the angle γ formed between the side surface of the convex portion 42a and the bottom surface of the concave portion 42b is 90 ° on both the upstream side and the downstream side of the convex portion 42a. That is, the angle γ on the downstream side in the surface movement direction of the developing roller 42 at the convex portion 42a (hereinafter referred to as “convex portion downstream angle γ1”) is 90 [°]. Further, the angle γ upstream of the developing roller 42 in the surface movement direction of the convex portion 42a (hereinafter referred to as “convex portion upstream angle γ2”) is 90 °.
As shown in FIG. 25, the stress of the doctor blade 45 acts in the direction of arrow Fb in the figure. Since the developing roller 42 moves in the direction indicated by the arrow B in the figure, the toner T carried in the recess 42b is subjected to a compressive force indicated by the arrow Fa in FIG. For this reason, if the toner in contact with the wall surface of the convex portion 42a on the downstream side in the surface movement direction of the developing roller 42 is not replaced, the compression force is applied to the specific toner, and the toner may aggregate. is there.

  On the other hand, as shown in FIG. 26, the developing roller 42 provided in the developing device 4 of Embodiment 1 has at least the convex downstream angle γ1 among the angles γ formed by the side surfaces of the convex portions 42a and the bottom surfaces of the concave portions 42b. Is formed to have an obtuse angle. Since the convex portion downstream angle γ1 is an obtuse angle, toner that contacts the wall surface of the convex portion 42a on the downstream side in the surface movement direction of the developing roller 42 is easily scraped by the supply roller 44, and the toner is replaced. Can be urged. By replacing the toner in contact with the wall surface, it is possible to prevent the compression force from acting on the specific toner and prevent the toner from aggregating.

  In the enlarged cross-sectional view of the surface of the developing roller 42 shown in FIG. As shown in FIG. 27, the contact state of the doctor blade 45 with the surface of the developing roller 42 allows the toner T present on the top surface 42t of the convex portion 42a to be worn off when the tip is in contact. More preferred.

FIG. 28 is an enlarged top view of the developing roller 42 in which one of two sets of parallel lines (opposite sides) of the rhombic top surface 42t of the convex portion 42a is orthogonal to the surface movement direction. As shown in FIG. 28, when one pair of the two opposite sides of the top surface 42t is orthogonal to the surface movement direction of the developing roller 42, a portion of the convex portion 42a on the downstream side in the surface movement direction of the developing roller 42 (FIG. The toner is easily compressed at a portion 42c in FIG. For this reason, filming tends to increase in the configuration shown in FIG.
On the other hand, as shown in FIG. 1B, the developing roller 42 included in the developing device 4 of Embodiment 1 has an elliptical top surface 42t. If the top surface 42t is elliptical, it can move in the direction along the surface movement direction along the edge of the top surface 42t from the downstream end of the top surface 42t. For this reason, it is difficult for the toner to be compressed at a portion of the convex portion 42a on the downstream side in the surface movement direction of the developing roller 42 (portion 42c in FIG. 1B).

In the developing device 4 of the first embodiment, the material of the doctor blade 45 (blade member 450), which is a restriction member, is made of metal.
In the developing devices described in Patent Document 1 and Patent Document 2, a rubber member is used as a regulating member that comes into contact with the developing roller on which a regular irregular shape is formed. However, in the configuration using the rubber regulating member, the amount of toner on the developing roller may vary when the protruding amount of the regulating member changes due to assembly tolerance at the time of manufacture or scraping of the blade used over time. Specifically, the toner on the developing roller becomes extremely small, the image density becomes thin, or conversely, the toner amount on the developing roller increases, charging failure occurs, and the background portion of the image becomes Occasionally, dirty soiling may occur.
On the other hand, by using a metal blade as the doctor blade 45 as in the developing device 4 of the first embodiment, even if the protruding amount of the doctor blade 45 changes within a certain range, The amount of toner can be stabilized.

  As the developing roller 42, a general-purpose material such as carbon steel (STKM or the like), Al (aluminum), or SUS can be used. For the doctor blade 45 (regulator blade), materials such as phosphor bronze (C5210), copper (C1202), beryllium copper (C1720), and stainless steel (SUS301, SUS304) can be used.

[Experiment 1]
Next, when the metal blade is used as the doctor blade 45 and the rubber blade is used, the stability of the toner amount on the developing roller 42 with respect to the change in the protruding amount of the doctor blade 45 is compared. Experiment 1 will be described.
Here, a method of changing the protruding amount of the doctor blade 45 will be described with reference to FIG.

First, the doctor blade 45 is brought into contact with the developing roller 42 in a state of edge contact so that the doctor blade 45 extends in a tangential direction (vertical direction in FIG. 29) at the initial contact position Q1 with respect to the developing roller 42. . Here, the edge contact means that the edge part forming the ridge line between the opposing surface 45b and the tip surface 45a of the doctor blade 45 contacts the surface of the developing roller 42 (the top surface 42t which is the surface of the convex part 42a). State. Here, the edge part 45e shows the vicinity of the virtual straight line where two virtual planes obtained by extending the facing surface 45b of the doctor blade 45 and the tip surface 45a intersect each other. And as the edge part 45e which forms the ridgeline used as the virtual straight line vicinity, the ridgeline may be rounded or it may be chamfered.
More specifically, a corner (edge 45e, which may be rounded or chamfered) on the developing roller 42 side at the free end of the flat doctor blade 45 may be convex. What is necessary is just to come in contact with the part 42a.

As shown in FIGS. 3 and 21, the edge contact direction is such that the portion where the doctor blade 45 is fixed (blade folder 45 c) is more than the portion where the doctor blade 45 is in contact with the developing roller 42. It is located downstream of the developing roller 42 in the direction of surface movement. That is, the free end is configured to abut against the rotation of the developing roller 42.
Here, as a method of bringing the doctor blade 45 into contact, there is a method in which a flat blade member is bent and the bent portion is brought into contact. However, as described above, the effect of scavenging the toner is the free end side of the blade member. The method in which the tips of the two are in contact is more effective and desirable. The doctor blade 45 protrudes from the downstream side in the surface movement direction of the developing roller 42 and is used as an edge.

  Next, the blade holder 45c (pedestal portion 452) that supports the base of the doctor blade 45 is moved along the normal direction of the developing roller 42 at the initial contact position Q1 (the direction indicated by the arrow X in FIG. 29A). Move to the side. As a result, as shown in FIG. 29 (b), the position of the doctor blade 45 that contacts the developing roller 42 moves to the base side, the doctor blade 45 bends, and the doctor blade 45 bends by abdominal contact. Contact in the state. Here, the bumping is a state in which the facing surface 45b of the doctor blade 45 facing the developing roller 42 is in contact, and the edge portion 45e is not in contact. Further, the contact position Q of the doctor blade 45 on the surface of the developing roller 42 at this time is displaced upward in FIG. 29 from the initial contact position Q1.

  In the state shown in FIG. 29B, the blade folder 45c is moved away from the developing roller 42 along the direction (vertical direction in FIG. 29) perpendicular to the normal direction at the initial contact position Q1 (arrow in FIG. 29). When it is moved in the Z direction), the amount of protrusion gradually decreases. And as shown in FIG.29 (c), it will be in the state of edge contact in the state in which the doctor blade 45 has bent. When the blade folder 45c is moved in the Z direction so that the protruding amount is further decreased from the state shown in FIG. 29C, the amount of deflection of the doctor blade 45 is increased until the doctor blade 45 is separated from the developing roller. The edge contact state is maintained while decreasing.

  When the doctor blade 45 is a metal blade (phosphor bronze) or a rubber blade made of urethane rubber, the protrusion amount is changed by the method for changing the protrusion amount described with reference to FIG. It was. FIG. 30 shows an experimental result obtained by measuring a change in the toner conveyance amount in the developing roller 42 at this time.

In the graph shown in FIG. 30, the position of the doctor blade 45 in the state shown in FIG. 29C in which the doctor blade 45 is changed from the stomach contact state to the edge contact state is set to zero. The displacement when the blade folder 45c is moved in the direction of the arrow Z in FIG. 29 from the zero position is − (minus), and when the blade folder 45c is moved in the direction opposite to the direction of the arrow Z in FIG. The displacement is shown as + (plus). In other words, the right side of the drawing in FIG.
A graph indicated by a broken line in FIG. 30 is an experimental result when a rubber blade is used, and a graph indicated by a solid line is an experimental result when a metal blade is used.

As shown in FIG. 30, when the position of the doctor blade 45 is in the + (plus) direction, the toner conveyance amount increases as the positions of both the metal blade and the rubber blade become positive.
On the other hand, when the position of the doctor blade 45 is in the − (minus) direction, a metal blade (solid line) has a region showing a stable conveyance amount as shown in FIG. 30. On the other hand, in the case of the rubber blade used in the conventional developing device (broken line), the toner was hardly conveyed onto the developing roller 42 at the position in the − (minus) direction.

According to Experiment 1 described with reference to FIG. 30, the amount of toner on the developing roller 42 is desired for the metal doctor blade 45 rather than the rubber for the amount of protrusion with respect to the developing roller 42 having a regular uneven shape on the surface. It was found that the range of the amount of protrusion as a quantity is wide.
Therefore, by using a metal blade as the doctor blade 45 as in the first embodiment, the margin of design tolerance in the Z direction in FIG. 29 when the doctor blade 45 is attached is increased, and assembling is improved. . Furthermore, the margin of mechanical tolerances is increased, and the cost of parts can be reduced.

FIG. 31 is an enlarged explanatory view of the contact position Q between the doctor blade 45 and the developing roller 42 in the edge contact state.
As described with reference to FIG. 30, when a metal blade is used as the doctor blade 45, the region where the toner amount is stable is obtained because the edge portion 45 e at the tip of the doctor blade 45 contacts the developing roller 42. It is to do. Specifically, as shown in FIG. 31, when the edge portion 45 e hits, the toner T is thinned so as to be worn by the doctor blade 45, so that the regular concave-convex concave portion 42 b of the developing roller 42 is formed. Only the buried toner T is conveyed. For this reason, the amount of toner on the surface of the developing roller 42 can be set to a desired amount according to the volume of the recess 42b, and the amount of toner transported by the developing roller 42 can be stabilized. In addition, since a metal blade has a certain degree of rigidity, its elasticity can bite into the recess 42b of the developing roller 42 and scrape the toner in the recess 42b more than that of a resin such as rubber. The amount of toner conveyed by the developing roller 42 can be stabilized.

[Experiment 2]
Next, by using a metal blade as the doctor blade 45, the range of the position of the doctor blade 45 that can maintain the edge contact when the value of the movement distance X1 in the normal direction at the initial contact position Q1 in FIG. The measured experiment 2 will be described.

FIG. 32 is a graph showing the experimental results of Experiment 2.
In the graph of FIG. 32, when the doctor blade 45 is in the tangential direction of the surface of the developing roller 42 at the contact position Q, the blade folder from FIG. 29A to FIG. The horizontal axis represents the value of the movement distance X1 of 45c. In the graph of FIG. 32, the blade folder 45c is moved from the state shown in FIG. 29B in the direction of arrow Z in the figure, and when the state shown in FIG. 29C is reached, the vertical axis is zero. Then, the blade folder 45c is further moved in the arrow Z direction in the drawing from the state shown in FIG. 29C, and the movement distance of the blade folder 45c in the Z direction in the drawing until the doctor blade 45 is separated from the surface of the developing roller 42. Is the vertical axis.

  From the graph shown in FIG. 32, when the moving distance X1 is zero or more, the doctor blade 45 can maintain the edge contact as the moving distance X1 in the normal direction of the surface of the developing roller 42 at the initial contact position Q1 increases. The range can be expanded. When the movement distance X1 is equal to or greater than zero, the doctor blade 45 is disposed so as to be bent by contact with the developing roller 42. By arranging in this way, when attaching the doctor blade 45, the margin of design tolerance in the vertical direction in FIG. 29 is increased, so that the assembling property is improved. Furthermore, the margin of mechanical tolerances is increased, and the cost of parts can be reduced.

[Experiment 3]
Next, as a metal blade used for the doctor blade 45, whether or not a streak image was generated was confirmed depending on whether the material was phosphor bronze or stainless steel (SUS). In this experiment, the Vickers hardness of the surface layer (surface layer 42f) of the developing roller 42 is set larger than phosphor bronze and smaller than stainless steel. Specifically, a developing roller 42 having a surface layer made of aluminum was used. In addition, as a measuring method of Vickers hardness, the method prescribed | regulated to JISZ2244 can be used.
The Vickers hardness of the phosphor bronze used in this experiment is 80 [Hv]. If a metal blade having a hardness lower than this is used as the doctor blade 45, it is considered that the doctor blade 45 has an effect of suppressing sticking similarly to the doctor blade 45 using phosphor bronze in this experiment. Regarding the hardness, Vickers hardness is adopted in this experiment, but comparison may be made by a method of measuring Brinell hardness and Rockwell hardness according to the material and shape.

In Experiment 3, the doctor blades 45 made of the respective materials are arranged in the state shown in FIG. 29C, and a solid image is formed using the copying machine 500 of the first embodiment to check for the occurrence of streak images. confirmed. As a result of Experiment 3, no streak image was generated when phosphor bronze was used as the material of the metal blade, and a streak image was generated when SUS was used.
Here, when the doctor blade 45 used in Experiment 3 was confirmed, the toner was fixed to the SUS doctor blade 45 in which the streak image was generated. On the other hand, toner sticking was hardly confirmed on the doctor blade 45 made of phosphor bronze where no streak image was generated.

FIG. 33 is a graph showing the results of measuring the amount of scraping of the doctor blade 45 with respect to the rotation time of the developing roller 42 for the doctor blade 45 of each material used in Experiment 3. A graph indicated by a broken line in FIG. 33 indicates a scraping amount when a SUS blade is used, and a graph indicated by a solid line is a scraping amount when a phosphor bronze blade is used.
It can be seen from FIG. 33 that phosphor bronze is easier to cut than SUS.
When the doctor blade 45 made of phosphor bronze is used, even if the toner is slightly fixed, the toner fixed together with the doctor blade 45 is scraped by sliding with the developing roller 42 before the toner fixing grows. . For this reason, it is considered that the sticking does not grow and the streak that causes a problem in the image does not occur.

If the hardness of the surface layer portion (surface layer 42f) of the developing roller 42 is set to be higher than the hardness of the contact portion of the doctor blade 45, the action of scraping the doctor blade 45 occurs, and the sticking is easily eliminated as described above. The effect of becoming.
Here, nickel plating or the like may be applied to increase the hardness of the surface layer of the developing roller 42. Further, even when the hardness of the surface layer of the developing roller 42 is increased, it is considered that phosphor bronze is more preferable for fixing toner because phosphor bronze is more easily scraped than stainless steel. Further, it is considered that a metal having a lower hardness than that of phosphor bronze (Vickers hardness of 80 [Hv] or less) has an effect of suppressing sticking.

As described in Experiment 3, as a configuration for preventing the generation of a streak image in the developing device 4 according to the first embodiment, the toner in the lightly fixed state is scraped off together with the doctor blade 45 by rubbing against the developing roller 42. . For this reason, it is necessary to cut the entire width direction of the doctor blade 45.
The developing roller 42 according to the first exemplary embodiment has the following configuration on the surface of the concavo-convex forming portion 420a that is a surface that carries the toner supplied to the photoreceptor 2. That is, at any position in the width direction (direction perpendicular to the surface movement direction) on the surface of the concavo-convex forming portion 420a, one or more top surfaces 42t are present during one round of the surface movement direction of the developing roller 42. To do. The top surface 42t is a surface that is the uppermost portion in the height direction of the convex portion 42a.

  As a configuration satisfying such a condition, the uneven shape on the surface at a certain position (the position of L11 in FIG. 1B, etc.) in the surface movement direction of the developing roller 42 of Embodiment 1 is a convex portion 42a in the width direction. And the recesses 42b are arranged in a periodic row. Further, the uneven shape at a position adjacent to this position in the surface movement direction (the position of L12 in FIG. 1B, etc.) is an arrangement in which the regular row arrangement is shifted by a half cycle. In other words, the row L12 adjacent to the row L11 in the surface movement direction has a shape in which the period of the unevenness in the width direction is shifted by a half cycle. Furthermore, the length W2a in the top surface axial direction is formed to be not less than ½ of the pitch width W1. The surface shape is such that such a shape is repeated in the direction of surface movement of the developing roller 42.

  With such a configuration, in the doctor blade 45, when the position of L11 of the developing roller 42 is in contact with the position of the top surface 42t, the top surface 42t is in contact with the position of L12. With such a configuration, it is possible to realize a configuration in which the top surface 42t of the developing roller 42 is brought into contact once over the entire region in the width direction of the doctor blade 45 while the developing roller 42 makes one round. In this way, the top surface 42t comes into contact with the developing roller 42 once in any position in the width direction of the doctor blade 45. This makes it possible to efficiently scrape the doctor blade 45, and it is possible to more reliably prevent the generation of streak images due to toner adhesion.

  In the configuration in which development is performed by bringing the surface of the developing roller 42 into contact with the photosensitive member 2, both the developing roller 42 and the photosensitive member 2 have no elasticity. A portion where the developing roller 42 does not contact occurs. In that case, the toner is not developed only in the portion where the photosensitive member 2 and the developing roller 42 are not in contact with each other, and image loss occurs. In order to prevent this, in the developing device 4 of the first embodiment, the developing roller 42 is disposed so as to form a gap with respect to the photoreceptor 2, and the developing roller 42 is connected to the developing roller 42 by the developing bias power supply 142. A voltage in which is superimposed is applied. Accordingly, the latent image is developed by jumping the toner T from the developing roller 42 to the photosensitive member 2, and image loss can be prevented regardless of the accuracy of the position of the developing roller 42 with respect to the photosensitive member 2.

In addition, the copier 500 as the image forming apparatus according to the first exemplary embodiment includes a notification system that notifies the user of replacement of the developing device 4 that has reached a preset life depending on the driving state of the developing device 4. Also good.
FIG. 34 is a flowchart of a notification system that notifies the replacement of the developing device 4. FIG. 35 is an enlarged explanatory view of the doctor blade 45 and the developing roller 42 included in the developing device 4 whose replacement time is approaching.

  As shown in FIG. 34, the driving time of the developing device 4 is counted (S1), and if it is determined that a predetermined driving time has been reached (Y in S1), it is assumed that the developing device 4 has reached the end of its life. . Then, the user is notified of the replacement or the fact that the developing device has reached the end of life through a lamp or a notification device such as a liquid crystal screen (S3). Here, regarding the parameter for determining the life, the driving time of the developing roller 42, the number of sheets to be passed, the energizing time to the developing device, and the like can be considered.

  As shown in FIG. 35, the doctor blade 45 edge-contacted with the developing roller 42 provided in the developing device 4 of Embodiment 1 has a contact portion (a portion indicated by a broken line “45d” in FIG. 35) by the developing roller 42. It will be shaved. Here, it is desirable that the thickness of the doctor blade 45 is set so that the tip surface 45a remains when the replacement notification based on the service life is performed. That is, the thickness is set with a margin with respect to the parameter so that the tip face 45a remains even if the parameter for determining the lifetime reaches the lifetime. If the tip surface 45a disappears due to cutting, the contact position between the doctor blade 45 and the developing roller 42 may change thereafter. Further, the tip of the doctor blade 45 having an acute angle may bite into the developing roller 42. Therefore, it is desirable to replace the doctor blade 45 with the tip end surface 45a remaining.

The developing device 4 according to the first embodiment has a toner T, which is a non-magnetic or magnetic one-component developer, carried on the surface thereof, the surface is moved endlessly, and a developing region facing the photoreceptor 2 that is a latent image carrier. A developing roller 42 which is a developer carrying member that supplies toner T to the latent image on the surface of the photoreceptor 2 with α and develops the toner T is provided. The developing device 4 is a plate-like member supported by a blade folder 45c, one end of which is a support member. The free end of the developing device 4 is in contact with the surface of the developing roller 42, and the amount of toner T toward the developing region α is measured. It has a doctor blade 45 which is a regulating member for regulating. Furthermore, the developing device 4 includes a concave portion 42 b and a convex portion 42 a that are concave and convex shapes on the surface of the developing roller 42. In such a developing device 4, the material of the doctor blade 45 that is a restricting member is made of metal, and an edge portion 45 e that is a free end side is in contact with the surface of the developing roller 42.
In the developing device 4, the material of the portion of the doctor blade 45 made of metal that contacts the developing roller 42 is preferably a material whose hardness is lower than that of the surface of the developing roller 42.

Next, the characteristic part of the developing roller 42 provided in the developing device 4 of Embodiment 1 will be described.
As shown in FIG. 1, the convex part 42a which forms the uneven | corrugated shape on the surface of the developing roller 42 is an elliptic frustum shape, The major axis direction is a direction along a surface moving direction. If the convex portion has an elliptical truncated cone shape, the portion on the most downstream side of the top surface 42t is a part of the elliptical circumference, and the contact pressure is concentrated on one point, so that the doctor blade 45 is partially It is possible to suppress the progress of wear. Moreover, it can suppress that the convex part 42a is abraded because contact pressure concentrates on one point. Therefore, durability can be improved compared with the case where the most downstream part of the top surface 42t is a corner. Due to the improvement in durability, it is possible to suppress a decrease in image density over time.

  Furthermore, since the major axis direction of the convex portion 42a having the elliptical truncated cone shape is the direction along the surface movement direction, the direction orthogonal to the surface movement direction is the minor axis direction, and the shape of the top surface 42t is an ellipse that is long in the surface movement direction. It becomes a shape. In such a shape, the shape of the edge portion going from the edge portion serving as the most downstream end portion on the top surface to the upstream side is a shape having a smaller spread in the direction perpendicular to the surface movement direction than in the case of a circular shape. Become. For this reason, the toner can move more easily in the direction along the surface movement direction along the edge portion than in the case where the top surface 42t is circular, the edge portion including the most downstream end portion on the top surface 42t, and the doctor blade It is possible to suppress the toner from being sandwiched between the toner and the toner. Therefore, it is possible to suppress the occurrence of toner filming resulting from the compression of the toner sandwiched between the edge portion of the top surface 42t and the doctor blade 45.

  Further, as shown in FIG. 1B, on the outer peripheral surface of the developing roller 42, the convex portions 42a are periodically arranged in a row with a pitch width W1 in the width direction, and the convex portions 42a are regularly formed. Yes. In the circumferential direction (surface movement direction), adjacent rows are arranged in such a manner that the regular row-like arrangement is shifted by a half cycle, and the convex portions 42a are regularly formed. As described above, the convex portions 42a are regularly formed in the width direction of the developing roller 42 and the surface moving direction to form a regular uneven pattern. Thereby, it is possible to suppress the variation in the toner carrying amount due to the difference in the position on the surface of the developing roller 42, so that the toner carrying amount is stabilized and the occurrence of uneven density during development can be suppressed.

The top surface axial length W2a of the convex portion 42a is preferably in the range of 50 [μm] to 200 [μm]. Moreover, it is preferable that the uneven | corrugated shaped pitch width W1 is the range of 50 [micrometers] or more and 250 [micrometers] or less. Further, the area ratio of the top surface 42t (the ratio of “the sum of the areas of all the top surfaces 42t of the plurality of convex portions 42a” to “the area of the entire peripheral surface of the unevenness forming portion 420a”) is 40% or more. 60 [%] or less is preferable. Here, the “area of the entire peripheral surface of the concavo-convex forming portion 420a” is not the actual surface area of the concavo-convex forming portion 420a having the concavo-convex shape, but the virtual surface where the position of the top surface 42t overlaps the surface of the concavo-convex forming portion 420a. In the case of a cylindrical shape, the surface area of the virtual cylindrical shape.
With such a configuration, the developing roller 42 can carry an optimum and uniform amount of toner in the recess 42b.

In the developing roller 42 according to the first embodiment, it is possible to prevent the toner from being sandwiched between the edge portion including the most downstream end portion on the top surface 42t and the doctor blade 45, and therefore stress on the toner in the recess 42b. Can be reduced.
As described above, in the developing device 4 including the developing roller 42 according to the first embodiment, stress on the toner, the doctor blade 45, and the developing roller 42 can be reduced, and a more highly durable image forming apparatus can be provided.

  In the developing roller 42 according to the first embodiment, as shown in FIG. 1C, when the boundary between the side surface of the convex portion 42a that is the lower end portion of the convex portion 42a and the bottom surface 42h of the concave portion 42b is viewed in a sectional view, It has a shape to be formed. On the other hand, when viewed in a cross-sectional view, there is a curvature from the side surface of the convex portion 42a to the bottom surface 42h of the concave portion 42b so that no corner is formed at the boundary between the side surface of the convex portion 42a and the bottom surface of the concave portion 42b. It is good also as a shape. Since the cross-sectional shape of the lower end portion of the convex portion 42a has a curvature, the toner easily moves inside the concave portion 42b. Thereby, it is possible to suppress toner filming on the surface of the developing roller 42 and a decrease in development efficiency due to toner filming. Further, since the toner becomes easy to move, stress on the toner can be suppressed and toner deterioration can be suppressed.

  In the developing roller 42 according to the first exemplary embodiment, it is preferable that the height (W3) of the convex portion 42a is not more than three times the average particle diameter of the toner. Accordingly, the toner flying property can be improved by making the toner layer accommodated in the recess 42b three or less.

  In the developing roller 42 of the first embodiment, the concavo-convex shape is formed by rolling. Usually, techniques such as etching and photolithography are mainly used for microfabrication at a level of several μm. However, by performing a rolling process, it is possible to manufacture at a lower cost and more easily. Further, in rolling, it is possible to process the uneven shape on the surface of the developing roller 42 into an arbitrary shape by creating a die in an arbitrary shape.

By using the developing roller 42 described above, the developing device 4 of Embodiment 1 can improve the durability while suppressing the occurrence of toner filming, and suppress the occurrence of image density unevenness and image density reduction. it can.
In addition, the process cartridge 1 according to the first embodiment includes the developing device 4 described above as a developing unit, and thus can improve the durability while suppressing the occurrence of toner filming. Generation | occurrence | production of a fall can be suppressed.
Further, the copier 500 according to the first embodiment includes a photoconductor 2 that is an image carrier, a charging member 3 that is a charging unit, and a developing unit. By having the developing device 4 described above as the developing means, it is possible to improve the durability while suppressing the occurrence of toner filming, and to suppress the occurrence of image density unevenness and image density reduction.

[Experiment 4]
Using a plurality of types of developing rollers 42 with different processing conditions, image formation was performed, and image density unevenness, image density reduction, and toner filming on the developing roller 42 (hereinafter also referred to as “roller filming”) were determined. .
In Experiment 4, each developing roller 42 was created by rolling using the following method.

  First, a sleeve (thickness 2 [mm]) made of STKM material was ground by a centerless grinder so that the outer diameter was 16 [mm]. On the other hand, 48 dies were prepared in which the shape and period width of the concave portions arranged in a spiral were changed. Using this die, the sleeve rotation speed is 500 [rpm], the φ48 die is pushed in by φ0.15 [mm], and the sleeve is scanned in the longitudinal direction of the sleeve at a speed of 0.6 [mm / rotation]. 42 surface irregularities were formed. Here, the speed of 0.6 [mm / rotation] is the moving speed of the die in the sleeve longitudinal direction, and the die is moved 0.6 [mm] in the sleeve longitudinal direction while rotating the sleeve once. It shows that. Further, Ni-P plating was applied to the surface of the developing roller 42 formed by rolling.

[Reference configuration example 1]
FIG. 36 is an explanatory diagram of the surface shape of the developing roller 42 of Reference Configuration Example 1. 36 (a) is a schematic view of the entire developing roller 42, FIG. 36 (b) is an enlarged top view of a region η in FIG. 36 (a), and FIG. 36 (c) is FIG. 36 (b). It is sectional drawing of an inside EE 'cross section.
As shown in FIG. 36, in the developing roller 42 of the reference configuration example 1, the convex portion 42a has a truncated cone shape. The developing roller 42 of Reference Configuration Example 1 has a pitch width W1 of 80 [μm], a top surface diameter W4 of 30 [μm], an angle γ of 120 [°], and a recess depth W3 of 18 [μm]. It produced so that it might become.

[Reference configuration example 2]
Similarly to the reference configuration example 1, the developing roller 42 of the reference configuration example 2 has the shape shown in FIG. 36, and the convex portion 42a has a truncated cone shape. The developing roller 42 of Reference Configuration Example 2 has a pitch width W1 of 100 [μm], a top surface diameter W4 of 30 [μm], an angle γ of 120 [°], and a recess depth W3 of 18 [μm]. It produced so that it might become.

[Reference Configuration Example 3]
FIG. 37 is an explanatory diagram of the surface shape of the developing roller 42 of Reference Configuration Example 3. 37A is a schematic diagram of the entire developing roller 42, FIG. 37B is an enlarged top view of the region η in FIG. 37A, and FIG. 37C is FIG. 37B. It is sectional drawing of an inside EE 'cross section.
As shown in FIG. 37, in the developing roller 42 of Reference Configuration Example 3, the shape of the convex portion 42a is a truncated cone, and the lower end portion of the convex portion 42a is rounded. The developing roller 42 of Reference Configuration Example 3 has a pitch width W1 of 80 [μm], a top surface diameter W4 of 30 [μm], an angle γ of 120 [°], and a recess depth W3 of 18 [μm]. It produced so that it might become.

[Reference Configuration Example 4]
FIG. 38 is an explanatory diagram of the surface shape of the developing roller 42 of Reference Configuration Example 4. 38A is a schematic view of the entire developing roller 42, FIG. 38B is an enlarged top view of a region η in FIG. 38A, and FIG. 38C is FIG. 38B. It is sectional drawing of an inside EE 'cross section.
As shown in FIG. 38, in the developing roller 42 of Reference Configuration Example 4, the shape of the convex portion 42a is an elliptic frustum shape, and the major axis direction of the elliptic frustum shape is parallel to the axial direction. The developing roller 42 of Reference Configuration Example 4 has a pitch width W1 of 80 [μm], a top surface axial direction length W2a of 50 [μm], a top surface movement direction length W2b of 20 [μm], and an angle γ Was 120 [°] and the recess depth W3 was 18 [μm]. In the reference configuration example 4, the length W2a in the top surface axis direction is the major axis of the elliptical top surface 42t, and the length W2b in the direction of top surface movement is the minor axis of the top surface 42t in the elliptical shape.

[Reference configuration example 5]
Similarly to the reference configuration example 1, the developing roller 42 of the reference configuration example 5 has the shape shown in FIG. 36, and the convex portion 42a has a truncated cone shape. The developing roller 42 of Reference Configuration Example 5 has a pitch width W1 of 80 [μm], a top surface diameter W4 of 30 [μm], an angle γ of 120 [°], and a recess depth W3 of 25 [μm]. It produced so that it might become.

〔Example〕
The developing roller 42 of the embodiment has the shape shown in FIG. 1, and the convex portion 42 a has an elliptic frustum shape, and the major axis direction of the elliptic frustum shape is parallel to the surface movement direction. Further, the developing roller 42 of the embodiment has a pitch width W1 of 80 [μm], a top surface axial direction length W2a of 20 [μm], a top surface moving direction length W2b of 50 [μm], and an angle γ of 120. [°] and the recess depth W3 was 18 [μm]. In the embodiment, the length W2a in the top surface axis direction is the short diameter of the elliptical top surface 42t, and the length W2b in the direction of top surface movement is the long diameter of the top surface 42t in the elliptical shape.

[Comparative Example 1]
FIG. 39 is an explanatory diagram of the surface shape of the developing roller 42 of the first comparative example. 39 (a) is a schematic view of the entire developing roller 42, FIG. 39 (b) is an enlarged top view of a region η in FIG. 39 (a), and FIG. 39 (c) is FIG. 39 (b). It is sectional drawing of an inside EE 'cross section.
As shown in FIG. 39, in the developing roller 42 of Comparative Example 1, the convex portion 42a has a square frustum shape with a square top surface 42t, and the concave portions 42b are formed in a lattice shape. The developing roller 42 of Comparative Example 1 has a pitch width W1 of 80 [μm], a top side length W5 of 20 [μm], an angle γ of 120 [°], and a recess depth W3 of 18 [μm]. ]. As shown in FIG. 39B, the developing roller 42 of Comparative Example 1 is provided with such a quadrangular pyramid-shaped convex portion 42a continuously in a spiral shape.

[Comparative Example 2]
The developing roller 42 of the comparative example 2 differs from the comparative example 1 shown in FIG. 39 in that the lower end of the convex portion 42a is rounded, and the shape of the convex portion 42a includes a square top surface 42t. It has a truncated pyramid shape, and the recesses 42b are formed in a lattice shape. The developing roller 42 of Comparative Example 2 has a pitch width W1 of 80 [μm], a top side length W5 of 20 [μm], an angle γ of 120 [°], and a recess depth W3 of 18 [μm]. ]. As shown in FIG. 39B, the developing roller 42 of Comparative Example 2 is provided with such a quadrangular pyramid-shaped convex portion 42a continuously in a spiral shape.

[Comparative Example 3]
As in Comparative Example 1, the developing roller 42 of Comparative Example 3 has the shape shown in FIG. 39. The convex portion 42a has a square frustum shape with a square top surface 42t, and the concave portion 42b has a lattice shape. Is formed. The developing roller 42 of Comparative Example 3 has a pitch width W1 of 100 [μm], a top side length W5 of 20 [μm], an angle γ of 120 [°], and a recess depth W3 of 18 [μm]. ]. As shown in FIG. 39B, the developing roller 42 of Comparative Example 3 is provided with such a quadrangular pyramid-shaped convex portion 42a continuously in a spiral shape.

The developing roller 42 of each of the reference configuration examples, the examples, and the comparative examples described above is incorporated in the copying machine 500 described with reference to FIG. 2, and AC (f = 500 to 10000 [Hz], Vpp = 500 to A rectangular wave of 3000 [V], Duty = 50 [%]) was used. Ten standard solid images were formed before and after the developing roller 42 was rotated equivalent to 100,000 sheets. (That is, 10 initial images and 10 time-lapse images were formed.)
Further, the developer used for image formation was prepared by a polymerization method, the average particle size was 6.5 [μm], the circularity was 0.98, the repose angle was 33 [°], and the external additive was used. A toner containing strontium titanate was used.
The experimental results are shown in Table 1.

  For each of the 10 initial images and the 10 time-lapse images, the density is measured using a spectral densitometer at three locations in the portion corresponding to one turn of the developing roller 42, and the portions in the portion corresponding to the one turn and thereafter are measured. The concentration was measured at three locations using a spectral densitometer. Here, the density of the portion corresponding to one rotation of the developing roller 42 (that is, the average density of the previous three locations) and the density of the portion corresponding to the one rotation and thereafter (that is, the average density of the subsequent three locations). The difference was calculated as density unevenness. Then, the average value of the density unevenness in the 10 initial images and the average value of the density unevenness in the 10 time-lapse images were further calculated and determined using the following determination criteria.

[Image density unevenness criteria]
“◯”: The average value of the density unevenness of the initial image and the time-lapse image is both less than 0.03 (a level that is difficult to visually confirm and causes no problem on the image).
"X": The average value of density unevenness of at least one of the initial image and the time-lapse image is 0.03 or more (a level that can be visually confirmed and causes a problem).

  Further, for each of the 10 initial images, an average value of the density at a total of six locations including the above three locations and the following three locations was calculated as the initial image density. Further, for each of the ten time-lapse images, the average value of the density at the six locations including the above three locations and the subsequent three locations was calculated as the time-lapse image density. Then, the average value of the initial image density in 10 initial images and the average value of the time-lapse image density in 10 time-lapse images were further calculated and determined using the following criteria.

[Image density reduction criteria]
“◯”: A decrease in the average value of the image density over time with respect to the average value of the initial image density is less than 10% (a level with no problem).
“×”: A decrease in the average value of the image density over time with respect to the average value of the initial image density is 10% or more (a level causing a problem as a product).

  Further, after rotating the developing roller 42 equivalent to 100,000 sheets, the presence of roller filming as toner filming on the surface of the developing roller 42 was confirmed using a microscope (VHX-1000 manufactured by Keyence Corporation). . The magnification was 500 times, the width direction was 3 places, the surface movement direction at that position was 4 places, and 12 places in total were confirmed.

[Criteria for white spot on image]
“◯”: When the developing roller 42 is rotated equivalent to 100,000 sheets and roller filming is not recognized.
“X”: When the filming is recognized after the developing roller 42 is rotated equivalent to 100,000 sheets.

[Embodiment 2]
Hereinafter, a second embodiment (hereinafter referred to as a second embodiment) of the present invention in which the present invention is applied to a printer (hereinafter referred to as a printer 600) as an image forming apparatus will be described.
FIG. 40 is a schematic cross-sectional view of a main part of the printer 600 according to the second embodiment. As shown in FIG. 40, the printer 600 includes a process cartridge 1 as four process units, an intermediate transfer belt 7, an exposure device 6 as exposure means, a fixing device 12 as fixing means, and the like. The intermediate transfer belt 7 is an intermediate transfer member that is stretched by a plurality of stretching rollers and moves in the direction of arrow A in FIG.

  Each process cartridge 1 has a structure in which a photosensitive member 2, a charging member 3, a developing device 4, and a photosensitive member cleaning device 5 are integrally supported. The photoreceptor 2 is a drum-shaped latent image carrier, and the charging member 3 is a charging unit. The developing device 4 develops a latent image on the photoreceptor 2 using toner T as a developer. Each process cartridge 1 can be attached to and detached from the printer 600 main body by releasing a stopper (not shown).

  The photoconductor 2 rotates in the clockwise direction in the figure as indicated by the arrow in the figure. The charging member 3 is a roller-shaped charging roller, is in pressure contact with the surface of the photoconductor 2, and is rotated by the rotation of the photoconductor 2. At the time of image formation, a predetermined bias is applied to the charging member 3 by a high voltage power source (not shown) to charge the surface of the photoreceptor 2. In the process cartridge 1 of the second embodiment, the roller-shaped charging member 3 that contacts the surface of the photoreceptor 2 is used as the charging unit. However, the charging unit is not limited to this, and non-contact such as corona charging. A charging method may be used.

  The exposure device 6 exposes the surface of the photoreceptor 2 based on image information, and forms an electrostatic latent image on the surface of the photoreceptor 2. The exposure apparatus 6 provided in the printer 600 uses a laser beam scanner system using a laser diode, but other configurations such as an exposure unit using an LED array may be used.

  The photoconductor cleaning device 5 cleans the transfer residual toner remaining on the surface of the photoconductor 2 that has passed the position facing the intermediate transfer belt 7.

  The four process cartridges 1 form toner images for the respective colors of yellow, cyan, magenta, and black on the photoreceptor 2. The four process cartridges 1 are arranged in parallel in the surface movement direction of the intermediate transfer belt 7 and transfer the toner images formed on the respective photoreceptors 2 in order to be superimposed on the intermediate transfer belt 7 in order. A visible image is formed on the belt 7.

  In FIG. 40, a primary transfer roller 8 serving as a primary transfer unit is disposed at a position facing each photoconductor 2 with the intermediate transfer belt 7 interposed therebetween. The primary transfer roller 8 is provided with a high voltage power supply (not shown). A primary transfer bias is applied to form a primary transfer electric field with the photoreceptor 2. By forming a primary transfer electric field between the photosensitive member 2 and the primary transfer roller 8, the toner image formed on the surface of the photosensitive member 2 is transferred to the surface of the intermediate transfer belt 7. One of a plurality of stretching rollers that stretch the intermediate transfer belt 7 is rotated by a drive motor (not shown), so that the intermediate transfer belt 7 moves in the direction of arrow A in the figure. A full color image is formed on the surface of the intermediate transfer belt 7 by sequentially transferring the toner images of the respective colors on the surface of the intermediate transfer belt 7 moving on the surface.

  On the downstream side in the surface movement direction of the intermediate transfer belt 7 with respect to the position where the four process cartridges 1 are opposed to the intermediate transfer belt 7, the intermediate transfer belt is opposed to the secondary transfer opposing roller 9a that is one of the stretching rollers. A secondary transfer roller 9 is disposed at a position facing the surface 7. The secondary transfer roller 9 forms a secondary transfer nip with the intermediate transfer belt 7. Further, a predetermined voltage is applied between the secondary transfer roller 9 and the secondary transfer counter roller 9a to form a secondary transfer electric field. Thereby, when the transfer paper P, which is a transfer material conveyed in the direction of arrow B in FIG. 40, passes through the secondary transfer nip, the full-color image formed on the surface of the intermediate transfer belt 7 is transferred to the transfer paper P. Transcribed.

  A fixing device 12 is disposed downstream of the secondary transfer nip in the conveyance direction of the transfer paper P. The transfer paper P that has passed through the secondary transfer nip reaches the fixing device 12, the full color image transferred onto the transfer paper P is fixed by heating and pressurization in the fixing device 12, and the transfer paper P on which the image is fixed is The data is output outside the printer 600.

  On the other hand, the toner T remaining on the surface of the intermediate transfer belt 7 without being transferred to the transfer paper P at the secondary transfer nip is collected by the transfer belt cleaning device 11.

  Next, the developing device 4 provided in the process cartridge 1 will be described with reference to FIGS. 41 and 42 are enlarged cross-sectional views of one of the four process cartridges 1. FIG. 41 is a cross-sectional view in the vicinity of the central portion in the axial direction of the developing roller 42. FIG. 42 is in the vicinity of the end portion in the axial direction. It is sectional drawing in the position where the side seal 59 of this is arrange | positioned. FIG. 43 is an explanatory sectional view of the developing device 4 in the vicinity of the rotation shafts of the toner conveying member 106, the toner agitating member 108, and the supply roller 44, which are arranged substantially linearly in the vertical direction. .

  The developing device 4 includes a toner storage chamber 101 that stores toner T, which is a developer, and a toner supply chamber 102 provided below the toner storage chamber 101. The toner storage chamber 101 and the toner supply chamber 102 are separated from each other. A partition member 110 is provided so as to partition. As shown in FIG. 43, the partition member 110 is provided with a plurality of openings. As a plurality of openings of the partition member 110, a supply port 111 that supplies the toner T in the toner storage chamber 101 to the toner supply chamber 102 and a return port 107 that returns the toner T in the toner supply chamber 102 to the toner storage chamber 101. And are provided.

  Below the toner supply chamber 102, a developing roller 42 as a developer carrier is provided. In the toner supply chamber 102, a supply roller 44, which is a developer supply member that supplies toner T to the surface of the developing roller 42, is provided in contact with the surface of the developing roller 42. Further, the toner supply chamber 102 is a regulating member that regulates the amount (layer thickness) of the toner T that is supplied onto the surface of the developing roller 42 by the supply roller 44 and moves toward the opposing portion of the photoreceptor 2 and the developing roller 42. The doctor blade 45 is provided in contact with the surface of the developing roller 42.

  The developing roller 42 is disposed in a non-contact manner with respect to the photoreceptor 2 and is applied with a predetermined bias from a high voltage power source (not shown).

  A toner conveying member 106 that conveys the toner T in the toner accommodating chamber 101 in a direction parallel to the rotation axis of the photoreceptor 2 (a direction orthogonal to the paper surface in FIG. 41) is provided in the toner accommodating chamber 101.

  Further, as the toner T stored in the toner storage chamber 101, a toner prepared by a polymerization method is used. The toner T is, for example, a toner T having an average particle diameter of 6.5 [μm], a circularity of 0.98, an angle of repose of 33 [°], and strontium titanate as an external additive. The toner T used in the printer 600 according to the second embodiment is not limited to this.

  As shown in FIG. 43, the toner conveying member 106 provided in the toner storage chamber 101 is a member having a rotation shaft that combines a conveying screw shape portion 106a and a conveying plate shape portion 106b. The toner conveying member 106 is configured to convey the toner T in the toner storage chamber 101 in a substantially horizontal direction (in the direction of arrow H in FIG. 43) parallel to the rotation axis of the toner conveying member 106 by the rotation operation of the conveying screw shape portion 106a. It has become. The developing device 4 includes a conveyance screw shape portion 106a that conveys the toner T in a direction parallel to the rotation axis of the toner conveyance member 106, but the developer conveyance member is not limited to this, and the conveyance device is not limited thereto. What has conveyance functions, such as a belt and a coiled rotating body, can be used. Furthermore, what has these conveyance functions and what has a loosening function, such as a paddle formed by bending a plate member such as a blade or a wire, may be combined.

  In the developing device 4 according to the second embodiment, the toner T is transported from the toner storage chamber 101 toward the supply roller 44 in a direction perpendicular to the rotation axis of the toner transport member 106 and substantially vertically downward. It has become. The toner T may be transported in a substantially horizontal direction perpendicular to the rotation axis of the toner transport member 106 as the transport direction of the toner T.

  A toner stirring member 108 is disposed in the toner supply chamber 102 vertically below the partition member 110. As shown in FIG. 43, the toner stirring member 108 is a member having a rotating shaft that combines a stirring screw-shaped portion 108a and a stirring plate-shaped portion 108b. The toner agitating member 108 conveys the toner T in the toner supply chamber 102 in a substantially horizontal direction (arrow I or J direction in FIG. 43) parallel to the rotation axis of the toner agitating member 108 by the rotation operation of the agitating screw shape portion 108a. It can be configured.

  As shown in FIG. 43, the agitating screw-shaped portion 108a of the toner agitating member 108 spirals so as to convey the toner T in the direction toward the outside (the direction of arrow I in FIG. 43) across the supply port 111 in the axial direction. Shaped wings are provided. Further, the stirring screw-shaped portion 108a of the toner stirring member 108 has spiral wings on the outside and inside of the two return ports 107 in the axial direction. For this reason, the toner T supplied from the supply port 111 to the toner supply chamber 102 is conveyed outward in the axial direction (in the direction of arrow I) by the rotation of the stirring screw shape portion 108a of the toner stirring member 108. Then, the toner T that has reached the outside of the return port 107 is conveyed toward the return port 107 (in the direction of the arrow J) by the stirring screw shape portion 108a whose wing portion is reversely wound. The transport direction of the toner T by the stirring screw-shaped portion 108 a is opposite between the outer side and the inner side in the axial direction across the return port 107, and a transfer force is applied to the toner T toward the return port 107. Below 107, the toner T is collected from both sides in the axial direction and pushed up in a mountain shape. As a result, when the amount of toner T supplied from the toner storage chamber 101 through the supply port 111 or the return port 107 to the toner supply chamber 102 is excessive, the toner T pushed up in the mountain shape by the return port 107 becomes the toner. The toner is returned from the supply chamber 102 to the toner storage chamber 101 through the return port 107. The toner agitating member 108 has a role of agitating the toner T in the toner supply chamber 102 and further supplying the toner T to the supply roller 44 and the developing roller 42 below.

The surface of the supply roller 44 is covered with a foam material having a structure having pores (cells), and the toner T supplied to the toner supply chamber 102 is efficiently attached and taken in, and the surface of the supply roller 44 is connected to the developing roller 42. Deterioration of the toner T due to pressure concentration at the contact portion is prevented. In addition, this foaming material is set to an electrical resistance value of 10 ³ to 10 ¹⁴ [Ω]. A supply bias is applied to the supply roller 44 and assists the operation of pressing the toner T preliminarily charged at the supply nip β in contact with the development roller 42 against the development roller 42. The supply roller 44 rotates in the counterclockwise direction in FIG. 41 as indicated by an arrow in FIG. 41 and supplies the toner T adhered to the surface so as to be applied to the surface of the developing roller 42.

  A doctor blade 45 as a regulating member is disposed so as to come into contact with the surface of the developing roller 42 on the downstream side in the surface movement direction of the developing roller 42 with respect to the supply nip β. The toner T supplied from the supply roller 44 to the surface of the developing roller 42 is conveyed to a position where the doctor blade 45 contacts with the rotation of the developing roller 42.

  As the doctor blade 45, a metal leaf spring material such as SUS304CSP, SUS301CSP, or phosphor bronze can be used. The doctor blade 45 has its free end abutted against the surface of the developing roller 42 with a pressing force of 10 to 100 [N / m], and the pressing force against the toner T on the developing roller 42. Let the bottom pass. As a result, the toner layer is thinned and a charge is applied to the toner T by frictional charging. In addition, a bias is applied to the doctor blade 45 by a bias power source (not shown) in order to assist the frictional charging of the toner T.

  The photosensitive member 2 is not in contact with the developing roller 42 and rotates in the clockwise direction in FIG. For this reason, in the developing region α where the developing roller 42 and the photosensitive member 2 face each other, the surface moving direction of the developing roller 42 and the surface moving direction of the photosensitive member 2 are the same direction.

  The thinned toner layer on the developing roller 42 is conveyed to the developing area α by the rotation of the developing roller 42. Then, in accordance with the bias applied to the developing roller 42 and the latent image electric field formed by the electrostatic latent image on the photosensitive member 2, it moves to the surface of the photosensitive member 2 and the electrostatic latent image on the surface of the photosensitive member 2. The image is developed.

  A discharge neutralization seal 109 as a lower seal member, which is a developer neutralization member, is developed at a location where the toner T that is not used for development in the development region α and remains on the developing roller 42 returns to the toner supply chamber 102 again. It is provided in contact with the roller 42. The neutralization seal 109 seals the toner T so as not to leak out of the developing device 4. A bias is applied to the static elimination seal 109 from a bias power source (not shown) to assist the static elimination capability.

  In the developing device 4 described above, development of the latent image on the photoreceptor 2 using the toner T on the developing roller 42 is performed as follows. The toner T supplied onto the surface of the developing roller 42 at the supply nip β is conveyed from the supply nip β toward the developing region α as the developing roller 42 rotates, and passes through a doctor blade 45 in the middle thereof. , Regulated to a predetermined amount. The toner T restricted to a predetermined amount is further transported to the developing area α, and the electrostatic latent image on the surface of the photosensitive member 2 is developed by the developing electric field between the developing roller 42 and the electrostatic latent image on the photosensitive member 2. It adheres to the image portion, and development is thereby performed. For the developing electric field, an AC bias is used such that a voltage in which the toner is directed toward the photosensitive member 2 and a voltage in which the toner returns to the developing roller 42 are alternately repeated. In the second embodiment, a rectangular wave with f = 500 to 10000 [Hz], Vpp = 500 to 3000 [V], and Duty = 50 to 90 [%] was used. Thereafter, the toner T that has not contributed to the development is further conveyed by the rotation of the developing roller 42, and the toner T returns to the toner supply chamber 102 and is repeatedly used.

  In the developing device 4 according to the second embodiment, the configuration including the developing roller 42 and the doctor blade 45 described in the first embodiment and the features of the present invention can be applied.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
In the developer carrying member such as the developing roller 42 that has a concave and convex shape such as a concave portion 42b and a convex portion 42a on the surface and carries the developer by carrying the developer such as toner on the surface and moving the surface, the concave and convex shape is provided. The convex part to be formed has an elliptic frustum shape, and the major axis direction is the direction along the surface movement direction.
According to this, as described in the first embodiment, when used in the developing device, it is possible to improve the durability while suppressing the occurrence of filming of the developer.
(Aspect B)
In (Aspect A), the convex portions such as the convex portions 42a are regularly arranged.
According to this, as described in the first embodiment, it is possible to suppress variation in the amount of developer such as toner due to a difference in position on the surface of the developer carrier such as the developing roller 42. Further, the amount of developer carried is stabilized, and the occurrence of uneven density during development can be suppressed.
(Aspect C)
In the aspect A or B, the lower end part of convex parts, such as the convex part 42a, has a curvature.
According to this, as described in the first embodiment, the developer such as toner can easily move inside the concave portion such as the concave portion 42b. Thereby, it is possible to suppress the filming of the developer on the surface of the developer carrying member such as the developing roller 42 and the decrease in the development efficiency due to the filming of the developer. In addition, since the developer can move easily, stress on the developer can be suppressed and deterioration of the developer can be suppressed.
(Aspect D)
In any one of the aspects A to C, the height of the convex portion such as the convex portion 42a is not more than three times the average particle diameter of the developer such as toner.
According to this, as described in the first embodiment, the developer layer accommodated in the recesses such as the recesses 42b can be three layers or less, and the flying property of the developer can be improved.
(Aspect E)
In any of the aspects A to D, the concave and convex shapes such as the concave portions 42b and the convex portions 42a are formed by rolling.
According to this, as described in the first embodiment, usually, fine processing of several [μm] level is mainly performed by a technique such as etching or photolithography. It can be manufactured at low cost and easily. Further, in rolling, it is possible to process the uneven shape on the surface of the developer carrying member into an arbitrary shape by creating a die in an arbitrary shape.
(Aspect F)
A developer such as a toner is carried on the surface, the surface moves endlessly, and the developer is developed into a latent image on the surface of the latent image carrier in a development area such as a development area α facing the latent image carrier such as the photoreceptor 2. In the developing device such as the developing device 4 provided with the developer carrying means for developing by supplying the developer, the developer carrying means is the developer carrying body according to any one of aspects A to E.
According to this, as described in the first embodiment, it is possible to obtain a stable image density over time and to improve durability while suppressing the occurrence of filming of the developer.
(Aspect G)
At least a latent image carrier and a developing unit in an image forming apparatus such as a copying machine 500 including a latent image carrier such as the photosensitive member 2 that carries the latent image and a developing unit that develops the latent image on the latent image carrier. In a process cartridge such as the process cartridge 1 that is held by a common holder as a unit and can be integrally attached to and detached from the main body of the image forming apparatus, the developing device of aspect F is used as developing means.
According to this, as described in the above embodiment, the developing device that can obtain a stable image density over time and suppress the filming of the developer is removed from the apparatus main body together with the other members constituting the process cartridge. be able to. For this reason, it is possible to perform stable development, and to improve the exchangeability of a highly durable developing device.
(Aspect H)
At least a latent image carrier such as the photosensitive member 2, charging means such as a charging member 3 for charging the surface of the latent image carrier, an exposure device 6 for forming an electrostatic latent image on the latent image carrier, and the like. In the image forming apparatus such as the copying machine 500 having the latent image forming means and the developing means for developing the electrostatic latent image into a toner image, the developing device of aspect F is used as the developing means.
According to this, as described in the first embodiment, a stable image density can be obtained over time, and the filming of the developer can be suppressed and the durability is high, so that stable image formation can be performed. An image forming apparatus capable of being provided can be provided.

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Photoconductor 4 Developing apparatus 6 Exposure apparatus 7 Intermediate transfer belt 12 Fixing apparatus 42 Developing roller 42a Convex part 42b Concave part 42f Surface layer 42g Base material 42h Bottom face 42t Top surface 44 Supply roller 45 Doctor blade 100 Printer part 200 Paper feed Portion 300 scanner portion 400 toner bottle 420 developing roller cylindrical portion 420a uneven portion forming portion 420b non-recessed portion forming portion 500 copier 600 printer P transfer paper W1 pitch width W2a top surface axial direction length W2b top surface moving direction length W3 concave portion depth Α Development area β Supply nip

Patent 469225 JP 2011-013700 A JP 2007-233195 A

Claims (8)

In the developer carrying body that has an uneven shape on the surface, carries the developer on the surface, and transports the developer by moving the surface,
The convex portion forming the concave-convex shape has an elliptic frustum shape, and a major axis direction thereof is a direction along the surface movement direction. The developer carrier of claim 1,
The developer carrying member, wherein the convex portions are regularly arranged. The developer carrier according to claim 1 or 2,
A developer carrier, wherein a lower end portion of the convex portion has a curvature. The developer carrying member according to any one of claims 1 to 3,
A developer carrying member, wherein the height of the convex part is not more than three times the average particle diameter of the developer. The developer carrying member according to any one of claims 1 to 4,
A developer carrier, wherein the uneven shape is formed by rolling. A developer carrying means is provided for carrying the developer on the surface and moving the surface endlessly, supplying the developer to the latent image on the surface of the latent image carrier and developing it in a development region facing the latent image carrier. In the developing device,
6. A developing device, wherein the developer carrying means is the developer carrying member according to claim 1. In an image forming apparatus comprising a latent image carrier that carries a latent image and a developing unit that develops the latent image on the latent image carrier, at least the latent image carrier and the developing unit are shared as a single unit. In a process cartridge configured to be held in a holding body and detachable integrally with the image forming apparatus main body,
A process cartridge using the developing device according to claim 6 as the developing means. At least a latent image carrier;
Charging means for charging the surface of the latent image carrier;
Latent image forming means for forming an electrostatic latent image on the latent image carrier;
In an image forming apparatus having developing means for developing the electrostatic latent image into a toner image,
An image forming apparatus using the developing device according to claim 6 as the developing means.

Images