JP2015049371A - Developing device, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can suppress the occurrence of abnormal discharge between a latent image carrier and an area outside a developer supply area of a developer carrier, and an image forming apparatus and process cartridge including the developing device.SOLUTION: There is provided a developing device including a developing roller 42 that carries toner on the surface, which makes endless movement, and supplies developer to a latent image on the surface of a photoreceptor 2 in a developing area α arranged opposite to the photoreceptor 2 to develop the latent image, and a doctor blade that is in contact with the surface of the developing roller 42 to regulate the amount of toner directed to the developing area α; and has a concavo-convex shape on the developer roller 42, where in the width direction orthogonal to the direction of surface movement of the developing roller 42, an insulation coating layer composed of an alumite coat is provided in a toner non-supply area 420e outside a toner supply area 420d, which is on the surface of the developing roller 42 and arranged opposite to the latent image on the surface of the photoreceptor 2 where the developer is supplied.

Description

  The present invention relates to a developing device used for a copying machine, a facsimile, a printer, and the like, and an image forming apparatus and a process cartridge using the developing device.

  Japanese Patent Laid-Open No. 2004-260688 discloses a concavo-convex pattern having a regular pattern in which the height of the convex portion and the depth of the concave portion are constant on the surface of the developing roller that conveys the developer to the developing region that is a portion facing the latent image carrier. A developing device is described. In this developing device, the developer in the developer accommodating portion is supplied to the surface of the developing roller by the developer supplying member, and the developer present on the convex portion of the developing roller is scraped off by the regulating member, so that the developer on the surface of the developing roller is removed. The developer is only the developer accommodated in the recess. Since the depth of the recess is constant and the formation pattern is regular, the developer carrying amount is substantially stabilized over the entire circumference of the developing roller. In such a developing device, a desired amount of developer can be transported to the developing region by setting the capacity of the recess to a capacity for carrying the desired amount of developer.

  In the developing device described in Patent Document 1, the developing roller, which is a developer carrier, and the latent image carrier are opposed to each other with a small gap in a non-contact state, and the developer carrier and the latent image carrier are between them. By forming a developing electric field, the developer is allowed to fly from the developer carrying member to the latent image carrying member. Thus, the developer is supplied to the latent image of the latent image on the latent image carrier and developed.

  Based on the difference in structure, the surface of the developer carrying member can be mainly divided into two regions: a concavo-convex formation region where desired concavo-convex is formed and a concavo-convex non-formation region where no concavo-convex is formed. When the direction perpendicular to the surface movement direction of the developer carrying member is defined as the width direction, the unevenness forming region is a region including a central portion in the width direction, and the unevenness forming region is more than both ends of the unevenness forming region in the width direction. This is the outer area. However, strictly speaking, due to the limitation of the processing method, a region in which an uneven shape with unstable processing accuracy is formed between the unevenness forming region and the unevenness forming region and the processing accuracy is unstable (hereinafter, “ An intermediate region ") may exist.

A developer supply region that supplies a developer on the surface of the developer carrying member facing the latent image on the surface of the latent image carrying member is required to supply the developer stably. By setting such a developer supply region so as to be within the range of the unevenness formation region inside the intermediate region, it becomes possible to supply the developer stably.
However, an unintended sharp protrusion may be formed in a region where machining accuracy is unstable, such as an intermediate region. In the development area, the developer is supplied by the potential difference between the surface of the developer carrier and the surface of the latent image carrier. If a sharp protrusion is formed on the surface of the developer carrier, this protrusion And the surface of the latent image carrier are likely to cause abnormal discharge. When abnormal discharge occurs, the potential difference between the surface of the developer carrying member and the surface of the latent image carrying member becomes unstable, leading to image degradation.

  The present invention has been made in view of the above problems, and an object thereof is to suppress the occurrence of abnormal discharge between a region outside the developer supply region of the developer carrier and the latent image carrier. A developing device, and an image forming apparatus and a process cartridge provided with the developing device are provided.

  In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that the developer is carried on the surface, the surface is moved endlessly, and the latent image on the surface of the latent image carrier is developed in the development region facing the latent image carrier. A developer carrying member for developing the developer by supplying the developer, and a regulating member that contacts the surface of the developer carrying member and regulates the amount of the developer toward the developing region. In a developing device having a concavo-convex shape on the surface of a body, a latent image on the surface of the latent image carrier is opposed on the surface of the developer carrier with respect to a width direction perpendicular to the surface movement direction of the developer carrier. Thus, an insulating coating layer is provided in a region outside the developer supply region for supplying the developer.

  According to the present invention, there is an excellent effect that it is possible to suppress the occurrence of abnormal discharge between the area outside the developer supply area of the developer carrier and the latent image carrier.

FIG. 3 is an enlarged explanatory view schematically showing one end of a developing roller and a photoreceptor in the width direction. 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. Explanatory drawing of the surface shape of a developing roller, (a) is the schematic of the whole developing roller, (b) is the enlarged top view and sectional drawing of area | region (eta) in (a). 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. 3 is an enlarged view of the surface of a shaft developing roller having a square top surface of a convex portion having a side perpendicular to the surface movement direction. Explanatory view of the contact state of the doctor blade with the developing roller, (a) is an explanatory view of the state where the blade is brought into contact with the tangential direction of the developing roller, (b) is a normal direction of the blade folder from the state of (a) Explanatory drawing of the state moved to (c), (c) is explanatory drawing 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. The graph which shows the experimental result of Experiment 4. 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.
First, the entire copying machine 500 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 an exposure unit, a fixing device 12 as a fixing unit, 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. Since the four process cartridges 1 (Y, M, C, K) have substantially the same configuration except that the colors of the toners used are different, the subscripts Y, M, C, K are omitted below. To 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.

Next, the developing device 4 will be described.
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.
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 T from the inside to the outside (the developing area α facing the photoconductor).
A remaining toner sensor 49 provided in the middle case 412 detects the amount of toner T 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. The side seal 59 prevents the toner T from leaking from the end portion of the opening 56 in the developing casing 41 in the longitudinal direction.
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 T is conveyed to the supply nip β which is a region, and the toner T is supplied to the surface of the developing roller 42. The developing roller 42 carries the supplied toner T on the surface, rotates in the direction of arrow B in FIG. 3 (clockwise direction in FIG. 3), and moves on the surface, whereby the toner on the developing roller 42 is transferred. The toner T is conveyed to a portion facing the doctor blade 45 that regulates T 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 of the developing roller 42 with respect to the surface of the developing roller 42). Abut). The toner T regulated to a predetermined amount at the portion facing the doctor blade 45 reaches the developing region 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 T 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 AC voltage to the developing roller 42. The AC voltage includes a first voltage for directing the toner T from the developing roller 42 to the photosensitive member 2 for developing the latent image by the toner T conveyed to the developing region α, and the developing roller 42 from the photosensitive member 2. A second voltage for directing the toner T toward the toner.

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, the toner T can be prevented from being carried on the developing roller 42, the toner T can be prevented from adhering to the surface of the developing roller 42, and the developer can adhere to the surface of the developer carrying member. It is possible to suppress the occurrence of density unevenness during development.
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 located above the surface of the toner T. In the configuration shown in FIG. 2 of Patent Document 1, the toner T is filled in the downstream area of the supply nip. In such a configuration, the toner T that is filled in the downstream area of the supply nip may inhibit new toner T from entering the downstream area of the supply nip. For this reason, there is a possibility that the recovery efficiency of the toner T from the developing roller 42 in the supply nip β may be reduced.

  On the other hand, in the developing device 4 of the first embodiment, as shown in FIG. 3, the downstream area of the supply nip is above the surface of the toner T. Therefore, the toner T is not filled in the downstream area of the supply nip, and the recovery of the toner T from the developing roller 42 in the supply nip β may be hindered by the toner T existing in the downstream area of the supply nip. Absent. Therefore, the toner T can be collected efficiently, and the resetability of the toner T 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. 14 is an explanatory view of the surface shape of the developing roller 42, FIG. 14 (a) is a schematic view of the entire developing roller 42, and FIG. 14 (b) is a region in FIG. 14 (a). It is an enlarged top view and sectional drawing of (eta). The cross-sectional view shown in the middle part of FIG. 14B shows the surface uneven shape 42S1 in the cross-sectional view along the straight lines indicated by L11 and L13 in the enlarged top view of the upper part. Moreover, the cross-sectional view shown in the lower part of FIG. 14B is the surface uneven shape 42S2 in the cross-section along the straight line indicated by L12 and L14 in the enlarged enlarged plan view of the upper part.

The developing roller 42 has a configuration in which a developing roller cylindrical portion 420 that carries the toner T on the surface thereof is provided on the developing roller shaft 421, and the developing roller in the vicinity of both end portions in the axial direction that is axially outside the developing roller cylindrical portion 420. A spacer 422 is provided on the shaft 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 shown in FIG. Rotate 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. 32). 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 uneven processing on the surface of the metal material sleeve that is the base material 42g, and nickel plating is performed on the metal material sleeve subjected to the uneven processing, thereby preventing corrosion of the developing roller 42, A surface layer 42f that assists charging of the toner T is formed.

As shown in FIG. 14A, the developing roller cylindrical portion 420 of the developing roller 42 is mainly divided into two portions (a groove forming portion 420a and a non-groove forming portion 420b) based on the difference in the surface structure. .
The groove forming portion 420a is a portion including a central portion in the axial direction of the developing roller 42, and is provided with a concavo-convex process on the surface thereof in order to properly carry the toner T. In the first embodiment, so-called rolling processing is used as the concavo-convex processing, and the convex portion 42a is formed so as to be surrounded by the spiral first groove L1 and the second groove L2 having different winding directions. By forming spiral grooves with different winding directions, mesh-like irregularities are formed on the surface of the developing roller 42. As the rolling process, a conventionally known processing method can be employed. The first groove L1 and the second groove L2 are each at a predetermined angle with respect to the axial direction of the developing roller 42 (in the first embodiment, both L1 and L2 are 45 [°], but the present invention is not limited to this. Not).

The first groove L1 and the second groove L2 are both periodically formed with a predetermined periodic width in the inclined direction, so that the convex portion 42a is formed with the pitch width W1 in the axial direction. Moreover, each inclination angle and period width of the 1st groove | channel L1 and the 2nd groove | channel L2 can also mutually differ. Further, the axial length W2 of the top surface 42t of the convex portion 42a is formed to be not less than ½ of the pitch width W1.
In the developing roller 42 of Embodiment 1, the pitch width W1 in the axial direction of the convex portion 42a is 80 [μm], and the axial length W2 of the top surface 42t of the convex portion 42a is 40 [μm]. Furthermore, the recess depth W3, which is the height from the bottom surface of the recess 42b to the top surface 42t of the protrusion 42a, is 10 [μm]. The values of the pitch width W1, the axial length W2 of the top surface 42t, 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 42 f be a material that normally charges the toner T. 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 T 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) Of toner T per unit area) is stabilized.

  Further, it is desirable that the height of the convex portion 42a (the concave portion depth W3) of the developing roller 42 is larger than the weight average particle diameter of the toner T to be used. Since the toner T having an average size fits in the recess 42b, it is difficult to select the particle size, and the M / A value with time (the amount of toner T carried per unit area on the surface of the developing roller) is stable. To do.

Next, the supply roller 44 will be described.
FIG. 15 is an explanatory perspective view of the supply roller 44, and FIG. 16 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 of the supply roller 44, and the cylindrical foam material has a supply roller cylindrical portion 440 that carries the toner T on the surface thereof. Become.

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 in FIGS. 3 and 6, 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.

  In the supply roller 44, a foam material is used for the supply roller cylindrical portion 440, 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 T 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”) It is set to be larger than the height 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 resetting property of the toner T in the concave portion 42b can be improved. 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 T will be pushed into the concave portion 42b, causing aggregation, and the amount of biting will be too large. It is necessary to set not to.

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 in pressing the toner T precharged 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.

  Further, the voltage applied to the supply roller 44 by the supply bias power supply 144 is relative to the normal charging polarity of the toner T (negative polarity in the toner T of the first embodiment) with respect to the AC voltage applied to the developing roller 42. Apply reverse polarity (positive polarity) DC voltage. At this time, the voltage applied to the supply roller 44 is opposite to the normal charging polarity of the toner T (plus polarity) 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 developing roller 42 is formed in the supply nip β, and the resetability of the toner T on the developing 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. In the case where the supply bias power supply 144 is not provided, the foam material used for the supply roller cylindrical portion 440 may be insulative. Further, depending on the specifications of the developing device 4, the material of the supply roller 44 may be a silicone rubber or nylon brush.

Next, the doctor blade 45 will be described.
FIG. 17 is a perspective explanatory view of the doctor blade 45, and FIG. 18 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 includes a tip contact state in which the tip contacts (edge contact described later) and a stomach contact state in which a surface portion closer to the root side than the tip contacts. The tip is in contact. In the tip contact state, the toner T present on the top surface 42t of the convex portion 42a can be worn out, and only the toner T present in the concave portion 42b is transported to the developing region α to be transported to the developing region α. The toner amount is stabilized.

  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 has a free end thereof brought into contact with the surface of the developing roller 42 with a pressing force of 10 to 100 [N / m], and the toner T that has passed under the pressing force is made a predetermined amount. Regulate and apply electric charge by frictional charging. Further, a bias may be applied to the blade member 450 from a doctor bias power source 145 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 is applied in a range of ± 200 [V] with respect to the AC voltage applied to the developing roller 42 can be mentioned. Thereby, it is possible to suppress fluctuations in the M / A value (the amount of toner T carried per unit area on the surface of the developing roller) due to environmental fluctuations.

Next, the paddle 46 will be described.
FIG. 19 is a perspective explanatory view of the paddle 46, and FIG. 20 is a side view of the paddle 46.
In the developing device 4, a toner accommodating portion 43 is provided as a space for accommodating toner T, 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.
A plurality of holes are arranged in the base portion of the paddle blade 460 so as to be parallel to the axial direction of the paddle shaft 461. The paddle shaft 461 has a plurality of convex portions arranged in two rows along the axial direction. Is provided. 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 blades 460, the toner T 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.

Next, the supply screw 48 shown in FIGS. 6 and 7 will be described.
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 T supplied from the toner supply port 55 toward the center of the developing device 4 in the longitudinal direction.

Next, the inlet seal 47 shown in FIGS. 3, 6 and 8 to 11 will be described.
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 the toner T in the developing device 4 will be described.
The toner T 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 is agitated 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 T supplied to the supply roller 44 is transferred to the surface of the developing roller 42 at the supply nip β where the supply roller 44 contacts the developing roller 42. Of the toner T transferred to the surface of the developing roller 42, the toner T exceeding the predetermined amount conveyed to the developing region α is scraped off from the surface of the developing roller 42 by the doctor blade 45.

  The toner T remaining on the surface of the developing roller 42 that has passed through the portion facing the doctor blade 45 is transported by the surface movement caused by the rotation of the developing roller 42 as it is, and reaches the developing region α facing the photoreceptor 2. The toner T 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 a supply nip β that is a position facing the supply roller 44. The toner T 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 is conveyed by the supply roller 44.

Next, the toner T used in the copier 500 according to the first embodiment will be described.
As the toner T used in the copying machine 500, it is desirable to use a toner having high fluidity so as to be compatible with high-speed toner conveyance. Specifically, it is desirable to use a toner having an accelerated aggregation degree of 40% or less. 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 sum of the above three calculated values is defined as the accelerated aggregation degree [%].

  As described above, the accelerated aggregation degree of 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. 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 charged, and furthermore, 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 of 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, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.

  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 the amines (B), the equivalent ratio [NCO] / [NHx of the isocyanate group [NCO] in the polyester prepolymer (A) having an isocyanate group and the amino group [NHx] in the amine (B). ]. 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. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers Inactive to polyvalent isocyanate compounds (PIC) such as benzene (such as tetrahydrofuran).

  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 [wt%], preferably 3 to 10 [wt%] based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

<Charge control agent>
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. 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. Preferably, the range of 0.2-5 [weight part] is good. If it exceeds 10 [parts by weight], the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attractive force with the developing roller 42 is increased, the developer fluidity is reduced, and the image The concentration is lowered.

<Release agent>
As a 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.
Waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, and petrolatum. And petroleum wax.
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, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer 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 master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the 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, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
Among these, as the fluidity imparting agent, it is preferable to use a combination of hydrophobic silica fine particles and hydrophobic titanium oxide fine particles.
Particularly when both the fine particles have an average particle diameter of 5 × 10 ⁻² [μm] or less and are stirred and mixed, the 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 to obtain a desired charge level, the fluidity-imparting agent is not detached from the toner, and good image quality that does not cause firefly is 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. Stable image quality can be obtained even when copying is repeated.

  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. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like 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 amount of the organic solvent used is usually 0 to 300 [parts by weight], preferably 0 to 100 [parts by weight], and more preferably 25 to 70 [parts by weight] with respect to 100 [parts by weight] of the polyester prepolymer.

  (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 an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

  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. As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. 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.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  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, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

  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 Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose 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 cause a reaction 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 base is removed to produce spindle-shaped toner base particles. . 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.

FIG. 21 is an enlarged explanatory view of the developer restricting portion of the developing device 4 in which the doctor blade 45 is applied to the stomach, and FIG. 22 is an enlarged explanatory view of the developer restricting portion of the developing device 4 in which the doctor blade 45 is applied to the tip. FIG.
As shown in FIGS. 3, 21, and 22, in the developing device 4 of the first embodiment, the developing roller 42 in which the arrow B direction in the drawing is the surface moving direction moves from the upper side to the lower side in the doctor portion. In such a case, since a downward force (Fg) is applied to the toner T due to its own weight acting on the toner T, the compressive force on the toner T due to the stress (Fb) of the doctor blade 45 can be reduced. Therefore, it is possible to suppress the toner T from aggregating at a portion (a portion 42c in FIGS. 21 and 22) on the downstream side in the surface movement direction of the developing roller 42 in the convex portion 42a 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 T that is a developer used in the developing device 4, it is desirable to use a toner T having an accelerated aggregation degree of 40% or less. This makes it possible to further alleviate the aggregation of the toner T at the portion of the convex portion 42a of the developing roller 42 on the downstream side in the surface movement direction of the developing roller 42 (portion 42c in FIG. 21). In the doctor section shown in FIG. 21, the doctor blade 45 is in a state of being bumped against the surface of the developing roller 42. As shown in FIG. 22, 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.

As shown in FIG. 23, 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 is reduced. Resulting in. Further, as shown in FIG. 24, 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. 25, 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. 25, when the angle γ is 90 ° or more, the probability that the supply roller 44 hits the toner T on the developing roller 42 is increased, so that the resetting property is improved.

FIG. 26 is an explanatory diagram of a configuration in which the angle γ formed by 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. 26, 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, unless the toner T in contact with the wall surface on the downstream side in the surface movement direction of the developing roller 42 in the convex portion 42a is replaced, a specific compressive force acts on the specific toner T, and the toner T aggregates. There is a fear.

  On the other hand, as shown in FIG. 27, 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, the toner T coming into 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 easily scraped by the supply roller 44. Can be replaced. By replacing the toner T in contact with the wall surface, it is possible to prevent the specific toner T from being repeatedly applied to the compression force and to prevent the toner T from aggregating.

  In the enlarged cross-sectional view of the surface of the developing roller 42 shown in FIG. 27, the doctor blade 45 is placed against the surface of the developing roller 42. As shown in FIG. 28, 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. In the developing device 4 of the first embodiment, the tip is in a contact state as shown in FIG.

  FIG. 29 is an enlarged top view of the developing roller 42 in which one of the 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. 29, when a pair of opposite sides of the top surface 42t are 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 (of 42c in FIG. 29). The toner T is likely to be compressed at (part). For this reason, in the configuration shown in FIG. 29, filming tends to increase.

  On the other hand, as shown in FIG. 14B, the developing roller 42 included in the developing device 4 of Embodiment 1 has two sets of parallel lines (opposite sides) on the rhombic top surface 42t of the convex portion 42a. All of these shapes have an angle with respect to a direction perpendicular to the surface movement direction of the developing roller 42. That is, there is an angle in the rubbing direction of the doctor blade 45 that abuts two sets of parallel lines (sides of the rhombic top surface 42t of the convex portion 42a) of the rhombic top surface 42t of the convex portion 42a. For this reason, it is difficult for the toner T 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. 14B). In the developing device 4 of the first embodiment, the angle formed by the side of the rhombic top surface 42t of the convex portion 42a and the surface moving direction of the developing roller 42 is 45 [°].

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 protruding amount of the regulating member changes due to assembly tolerance at the time of manufacture or scraping of the blade used over time, and the toner amount on the developing roller may vary. Specifically, the toner on the developing roller becomes extremely small and the image density becomes thin, or conversely, the toner amount on the developing roller increases and charging failure occurs, and the background portion of the image becomes dirty. Sometimes soiling occurred.
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. 30) at the initial contact position Q1 with respect to the developing roller 42. . Here, the edge contact means that an edge portion 45e (see FIG. 32 to be described later) forming a ridge line between the opposing surface 45b of the doctor blade 45 and the tip surface 45a is the surface of the developing roller 42 (the surface of the convex portion 42a). It is in a state of contacting a certain top surface 42t). 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.

Further, as shown in FIGS. 3 and 22, 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 for bringing the doctor blade 45 into contact, there is also a method in which a flat blade member is bent and the bent portion is brought into contact with each other. The method of contacting the tip on the side 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 root of the doctor blade 45 is moved along the normal direction of the developing roller 42 at the initial contact position Q1 (in the direction of arrow X in FIG. 30A). Move to the side. As a result, as shown in FIG. 30 (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 stomach pad 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 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. 30 from the initial contact position Q1.

  A direction (arrow in FIG. 30) away from the developing roller 42 along a direction (vertical direction in FIG. 30) perpendicular to the normal direction at the initial contact position Q1 from the state shown in FIG. 30 (b). When moved in the Z direction), the amount of protrusion gradually decreases. Then, as shown in FIG. 30 (c), the doctor blade 45 is in an edge contact state with the doctor blade 45 still bent. When the blade folder 45c is moved in the Z direction so that the amount of protrusion further decreases from the state shown in FIG. 30C, 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 made of metal (phosphor bronze) or a rubber blade made of urethane rubber, the protrusion amount is changed by the method of changing the protrusion amount described with reference to FIG. It was. FIG. 31 shows the experimental results of measuring the change in the toner conveyance amount at the developing roller 42 at this time.

In the graph shown in FIG. 31, the position of the doctor blade 45 in the state shown in FIG. Then, the displacement when the blade folder 45c is moved in the direction of the arrow Z in FIG. 30 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. 31 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. 31, 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 increase to plus.
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. 31. On the other hand, in the case of the rubber blade used in the conventional developing device (broken line), the toner T was hardly conveyed onto the developing roller 42 at the position in the − (minus) direction.

According to Experiment 1 described with reference to FIG. 31, the amount of toner on the developing roller 42 is more desirable for the metal doctor blade 45 than the rubber for the protruding amount 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. . Furthermore, the margin of mechanical tolerances is increased, and the cost of parts can be reduced.

FIG. 32 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. 31, when a metal blade is used as the doctor blade 45, an area 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. 32, when the edge portion 45e hits, the toner T is thinned so as to be worn by the doctor blade 45, so that the regular concave-convex concave portion 42b 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 T conveyed by the developing roller 42 can be stabilized. In addition, since the metal blade has a certain degree of rigidity, it is more likely than a resin such as rubber to bite into the recess 42b of the developing roller 42 due to its elasticity and scrape the toner T in the recess 42b. Is also low. For this reason, the transport amount of the toner T by the developing roller 42 can be stabilized.

  In the graph shown in FIG. 31, the left side (minus direction) is in the tip contact state with respect to the position of “0” in the central portion in the left-right direction of the graph, and the right side (plus direction) is relative to the position of “0”. It is the state of the stomach. As shown in FIG. 31, in the case of the tip contact, it can be seen that even if the position of the doctor blade 45 fluctuates, the transport amount is not affected. For this reason, by using the tip contact, the assembly accuracy can be relaxed, and the effect of improving the assembly and reducing the cost can be obtained.

[Experiment 2]
Next, 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. 33 is a graph showing the experimental results of Experiment 2.
In the graph of FIG. 33, 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. The horizontal axis represents the value of the movement distance X1 of 45c. In the graph of FIG. 33, the blade folder 45c is moved in the arrow Z direction in the drawing from the state shown in FIG. 30B, and when the state shown in FIG. Then, the blade folder 45c is further moved in the arrow Z direction in the drawing from the state shown in FIG. 30C, 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. 33, 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. 30 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 Experiment 3, 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.

In Experiment 3, the doctor blades 45 made of the respective materials are arranged in the state shown in FIG. 30C, 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 T was fixed to the SUS doctor blade 45 in which the streak image was generated. On the other hand, the toner T was hardly adhered to the phosphor bronze doctor blade 45 where no streak image was generated.

FIG. 34 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. 34 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.
FIG. 34 shows that phosphor bronze is easier to cut than SUS.
When the doctor blade 45 made of phosphor bronze is used, even if the toner T is slightly fixed, the toner T fixed together with the doctor blade 45 by rubbing with the developing roller 42 before the toner T is fixed. Is cut. 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 the toner T because phosphor bronze is more easily scraped than stainless steel.
The phosphor bronze used in Experiment 3 has a Vickers hardness of 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 as in the doctor blade 45 using phosphor bronze in Experiment 3. Regarding the hardness, Vickers hardness is adopted in Experiment 3, but comparison may be made by a method of measuring Brinell hardness and Rockwell hardness according to the material and shape.

As a configuration for preventing the generation of a streak image in the developing device 4 according to the first embodiment, the toner T that is slightly fixed together with the doctor blade 45 is scraped by sliding with 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 groove forming portion 420a that is a surface that carries the toner T 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 groove forming portion 420a, one or more top surfaces 42t are present during one rotation in 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 in the surface movement direction of the developing roller 42 (the position of L11, etc.) is such that the convex portions 42a and the concave portions 42b are arranged in a periodic row in the width direction. Has been placed. In addition, the uneven shape at a position adjacent to the position in the surface movement direction (the position of L12, etc.) with respect to this position is an arrangement in which the regular row arrangement is shifted by a half cycle (see FIG. 14). In other words, the rows L12 and L14 adjacent to the surface L11 and the row L13 in the surface movement direction have a shape in which the period of the unevenness in the width direction is shifted by a half cycle. Further, the axial length W2 of the top surface 42t 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 the developing roller 42 is in contact with the position L11, the position where the top surface 42t is not in contact comes into contact with the top surface 42t when the position of L12 is in contact. 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. As a result, the doctor blade 45 can be efficiently scraped, and the generation of streak images due to the sticking of the toner T can be more reliably prevented.

  In the first embodiment, since the developing roller 42 and the photoconductor 2 are not elastic, in the configuration in which development is performed with the surface of the developing roller 42 in contact with the photoconductor 2, depending on the accuracy of the developing roller 42 and the photoconductor 2. A portion where the photoreceptor 2 and the developing roller 42 do not come into contact with each other occurs. In that case, only the portion where the photoreceptor 2 and the developing roller 42 are not in contact with each other is not developed with the toner T, and an image defect 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. 35 is a flowchart of a notification system that notifies the replacement of the developing device 4. FIG. 36 is an enlarged explanatory view of the doctor blade 45 and the developing roller 42 provided in the developing device 4 whose replacement time is approaching.

  As shown in FIG. 35, 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 S2), 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. 36, the doctor blade 45 that is edge-contacted with the developing roller 42 provided in the developing device 4 of Embodiment 1 has a contact portion (portion indicated by a broken line “45d” in FIG. 36) 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.

Next, problems of a conventional developing device having a concavo-convex shape on the surface of the developer carrying member will be described.
In order to form a regular concavo-convex shape on the developer carrying member, when the concavo-convex processing is performed on the developer carrying member by a rolling process, it is sufficiently transferred to the portion on the surface of the developer carrying member where processing starts. An area that is not processed is created. Even in this case, a sharp portion may be formed due to insufficient processing.

  Further, when using a developer bearing member having regular irregularities, a metal roller is used so that the function of cutting off the toner and stabilizing the transport amount can be sufficiently obtained as in the developing device 4 of the first embodiment. In many cases, the surface is processed with unevenness. When such a metal roller is used for the developer carrying member, a belt-like photosensitive member may be used and development may be performed by pressing an elastic roller against the developer carrying member from within the belt. Further, as another configuration in the case of using a metal roller, a developer gap is provided between the developer carrier and the photosensitive member, and an AC waveform is applied during development so that the toner is transferred to the developer carrier. A configuration using an AC jumping development system for jumping from the toner to the photosensitive member can be considered.

Among these configurations, in the system using the belt-shaped photoconductor described above, the belt photoconductor is poor in handleability and processability, and also requires a distance of the photosensitive layer. It leads to cost increase. For this reason, the AC jumping development method described later is often used.
In the case of the jumping development method, a development gap is formed between the developer carrier and the photoreceptor by providing a gap roller member at the end of the developer carrier and abutting it against the photoreceptor to form a development gap. . When such a jumping development method is employed, if there is a sharp portion on the developing roller side, abnormal discharge is likely to occur.

  If an abnormal discharge occurs between the developer carrying member and the photosensitive member, an excessive current flows, disturbing the waveform of the generated AC bias from the high-voltage power supply of the apparatus main body, and developing performance Drop or streak-like abnormal images.

Next, features of the developing device 4 according to the first embodiment will be described.
FIG. 1 is an enlarged explanatory view schematically showing one end portion of the developing roller 42 and the photosensitive member 2 in the width direction in the developing region α.

  As described with reference to FIG. 14, the developing roller cylindrical portion 420 of the developing roller 42 is mainly divided into two portions (a groove forming portion 420a and a non-groove forming portion 420b) based on the difference in the structure of the surface. However, strictly speaking, due to the limitation of the processing method, as shown in FIG. 1, a groove forming intermediate portion 420c may be formed between the groove forming portion 420a and the non-groove forming portion 420b.

  Specifically, when rolling and forming a concavo-convex shape with respect to the developing roller 42, first, a die (such as a roller-shaped die for applying a concavo-convex shape) is pressed against the developing roller 42. The torque varies, the pressing pressure varies, and the uneven shape varies. When such uneven unevenness is formed in the toner supply region 420d, the amount of toner T supplied to the latent image on the photoreceptor 2 will vary.

  On the other hand, a die is shallowly applied to a position where the toner non-supply area 420e does not contribute to development at first, and a groove that becomes a concave and convex shape is started from a low torque state. Then, the groove is gradually applied deeply, and in the toner supply region 420d that is actually used for development, a groove having a desired depth is formed with a stable torque. Thus, a groove forming intermediate portion 420c in which the processing accuracy becomes unstable at the beginning of applying the die is formed in the toner non-supply region 420e so that a desired uneven shape is formed in the toner supply region 420d.

The groove forming intermediate part 420c is a part whose processing accuracy is unstable compared to the groove forming part 420a, and an unintended sharp edge may occur.
The developing roller 42 is made of metal, and the sharp edge of the metal has an effect of strengthening the electric field formed in the developing region α, so that abnormal discharge is induced.

The surface of the photoreceptor 2 can be divided into two regions, an image region 2a and a non-image region 2b, on which a latent image can be formed, depending on whether or not a latent image can be formed. The image area 2a is an area including a central portion in the width direction, and the non-image area 2b is an area outside the both ends in the width direction of the image area 2a.
On the surface of the developing roller 42, an area facing the image area 2a on the surface of the photoreceptor 2 is a toner supply area 420d, and an area facing the non-image area 2b is a toner non-supply area 420e.

As shown in FIG. 1, the toner supply region α is set so as to be within the range of the groove forming portion 420a in which the concavo-convex shape is accurately formed inside the groove forming intermediate portion 420c. As a result, the transport amount of the toner T by the developing roller 42 is stabilized, and the toner T can be stably supplied to the photoreceptor 2.
However, if abnormal discharge occurs between the sharp edge formed in the groove forming intermediate portion 420c and the surface of the photoreceptor 2, the potential difference between the surface of the developing roller 42 and the surface of the photoreceptor 2 becomes unstable. As a result, developability is lowered and streaky abnormal images are generated, which leads to image deterioration.

  On the other hand, in the developing device 4 of the first embodiment, the toner supply region that supplies the toner T on the surface of the developing roller 42 facing the latent image on the surface of the photoreceptor 2 in the width direction of the developing roller 42. An insulating coating layer is provided in the toner non-supply area 420e, which is an area outside 420d. Accordingly, the groove forming intermediate portion 420c existing in the toner non-supply area 420e can be covered with the insulating coating layer, and even if a sharp edge is formed on the groove forming intermediate portion 420c, the groove forming intermediate portion 420c is covered with the insulating coating layer. Therefore, the occurrence of abnormal discharge can be suppressed. Thereby, it is possible to suppress the deterioration of the image due to the abnormal discharge. In the first embodiment, alumite coating is used as the insulating coating layer. However, the coating layer is not limited to this as long as the coating layer can insulate between the surface of the developing roller 42 and the photoreceptor 2.

  In addition, if an insulating coating layer is provided in the toner supply region 420d, which is a developer supply region, it is impossible to inject charge from the developing roller 42 to the toner T carried in the recess 42b. The toner supply region 420d is not provided with an insulating coating layer. As a result, it is possible to inject the charge from the developing roller 42 to the toner T carried in the recess 42b, and the weakly charged toner having an insufficient charge amount is conveyed to the developing region α to be used as a weakly charged toner such as a scum. It is possible to prevent the occurrence of problems caused by it.

  Since the developing roller 42 according to the first embodiment is made of aluminum and is made of metal, electric discharge is likely to occur due to a sharp portion in the groove forming intermediate portion 420c. However, in the first embodiment, the occurrence of discharge can be prevented by providing an insulating coating layer in the groove forming intermediate portion 420c.

  In the first embodiment, the surface of the developing roller 42 is nickel-plated to form a surface layer 42 f that prevents corrosion of the developing roller 42 and assists charging of the toner T. When the plating process is performed after the insulating coating layer is provided in the configuration in which the insulating coating layer is provided, the outermost surface of the developing roller 42 becomes a plated surface, and the outermost surface of the portion provided with the insulating coating layer also has a plated surface. Become. When the plated surface is the outermost surface, the outermost surface of the portion provided with the insulating coating layer and the base material 42g made of aluminum or the like of the portion not provided with the insulating coating layer can be energized through the plating. It becomes a state. In such a state, even if the pointed portion is covered with an insulating coating layer, abnormal discharge may occur between the plating portion on the outermost surface and the surface of the photoreceptor 2.

  On the other hand, the developing roller 42 according to the first embodiment is coated with an insulating coating layer after being plated. As a result, the insulating coating layer becomes the outermost surface, and the sharp portion is covered with the insulating coating layer, whereby abnormal discharge between the surface of the developing roller 42 and the surface of the photoreceptor 2 can be suppressed.

[Experiment 4]
Next, using the developing roller 42 having an insulating coating layer and the developing roller 42 not having an insulating coating layer, the amplitude of the developing bias to which the AC bias is applied is changed, and the development bias power supply 142 and the developing roller 42 are Experiment 4 in which changes in the current flowing between them are confirmed will be described.
FIG. 37 is a graph showing the experimental results of Experiment 4. In FIG. 37, the horizontal axis represents the amplitude of the AC developing bias as the developing bias, and the AC developing bias amplitude is larger toward the right side. Also, the vertical axis in FIG. 37 represents the calculated value of the current when the current flowing between the developing bias power supply 142 and the developing roller 42 increases linearly with respect to the increase of the developing bias, and actually flows. The difference (ΔI) from the measured current value is shown.

As shown by “V = I × R” (V: voltage, I: current, R: resistance), the normal flowing current is that “V” and “I” are linear if “R” is constant. Should be the relationship. However, when an abnormal current occurs, the value of the current that actually flows becomes a value “I ′” that is different from “I” that is linearly related to “V”. In this way, when the development bias “V” is increased, the calculated value of the current when increasing in a linear relationship is “I”, and the measured value of the actually flowing current is “I ′”. The difference between “I” and “I ′” is “ΔI”.
The measured value of the actually flowing current was measured by inserting a current measuring device (MULTIMETER_87 manufactured by FLKE) into the path between the developing bias power source 142 and the developing roller 42.

  In Experiment 4, two types of developing rollers 42 described below are used, and the developing bias power supply 142 increases the AC bias of the developing bias applied to the developing roller 42 step by step. The current flowing between was measured. Further, development was performed when the AC bias was increased stepwise, and it was verified whether an abnormal image occurred in the output image.

Example 1 (solid line): Using a developing roller provided with an insulating coating layer in the toner non-supply area 420e Example 2 (broken line): Using a developing roller not provided with a rolling insulating coating layer

As shown in FIG. 37, in the case of Example 1, ΔI indicating the occurrence of abnormal current starts from the region “III” in FIG. 37, and in Example 2, the development bias is higher than that in the region “III”. ΔI indicating the occurrence of abnormal current starts to occur from the region “II” in FIG.
Therefore, Example 1 using the developing roller provided with the insulating coating layer has a larger amplitude of the developing bias at which abnormal current starts to occur, and Example 2 using the developing roller not provided with the insulating coating layer. It can be seen that the abnormal current starts to occur from the state of the developing bias having a smaller amplitude.

  Table 1 shows the result of confirming whether or not an abnormal image was generated in the image output using the AC developing bias in each region of “I” to “IV” in Experiment 4.

A case where an abnormal image did not occur was indicated as “◯”, and a case where a streak-like abnormality occurred in the image was indicated as “X”. As a result, it has been found that the configuration of Example 1 including the characteristic portion of Embodiment 1 is less likely to generate an abnormal image.
As described above, the developing device 4 according to the first exemplary embodiment has an excellent effect that it is possible to suppress the occurrence of an abnormal image due to the abnormal discharge at the end portion in the width direction of the developing roller 42.

[Experiment 5]
Next, Experiment 5 in which the durability of the developing roller 42 is confirmed using the developing roller 42 that has been anodized as the insulating coating layer and the developing roller 42 that has been coated with polycarbonate as the insulating coating layer will be described.

In Experiment 5, two types of developing rollers 42 described below were used, and durability was maintained under conditions of an image area ratio of 5 [%] and 3 [P / J] (printing three sheets continuously, pausing, and repeating this operation). A test was conducted.
Example 1: Anodized coating as an insulating coating layer Example 3: Polycarbonate coating as an insulating coating layer

  The results of Experiment 5 are shown in Table 2.

  As shown in Table 2, Example 3 was 1.0 [k sheets] and the insulating coating layer was peeled off, whereas in Example 1 in which anodizing was performed as in Embodiment 1, the durability test was performed. The insulation coating layer did not peel off until the last 5.0 [k sheets]. Accordingly, it was confirmed that the use of an alumite coat as the insulating coating layer has an excellent effect of suppressing the occurrence of abnormal images due to abnormal discharge at the end in the width direction of the developing roller 42 over time.

[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. 38 is a schematic cross-sectional view of a main part of the printer 600 according to the second embodiment. As shown in FIG. 38, 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. 38, 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 driven by a high voltage power source (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.

  With respect to the position where the four process cartridges 1 are opposed to the intermediate transfer belt 7, the intermediate transfer belt 7 is located on the downstream side in the surface movement direction with respect to the secondary transfer counter roller 9 a that is one of the stretching rollers. A secondary transfer roller 9 is disposed at a position facing the belt 7 across the belt 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. Thus, when the transfer paper P, which is a transfer material conveyed in the direction of arrow B in FIG. 38, 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. 39 and 40 are enlarged cross-sectional views of one of the four process cartridges 1. FIG. 39 is a cross-sectional view in the vicinity of the central portion in the axial direction of the developing roller 42. FIG. 40 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. 41 is a cross-sectional explanatory 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 that 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. 41, 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, in the toner supply chamber 102, a doctor blade 45 as a regulating member is provided in contact with the surface of the developing roller 42. The doctor blade 45 is supplied onto the surface of the developing roller 42 by the supply roller 44, and regulates the amount (layer thickness) of the toner T toward the facing portion between the photoreceptor 2 and 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 photosensitive member 2 (a direction orthogonal to the paper surface in FIG. 39) is provided in the toner accommodating chamber 101.

  In addition, the toner T stored in the toner storage chamber 101 is made by a polymerization method. 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. 41, the toner conveying member 106 provided in the toner storage chamber 101 is a member having a rotating shaft in which a conveying screw shape portion 106a and a conveying plate shape portion 106b are combined. 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. 41) 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 106 a that conveys the toner T in a direction parallel to the rotation axis of the toner conveyance member 106. However, the developer conveying member is not limited to this, and a developer having a conveying function such as a conveying belt or 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. 41, the toner agitating member 108 is a member having a rotating shaft in which an agitating screw shape portion 108a and an agitating plate shape portion 108b are combined. The toner agitating member 108 conveys the toner T in the toner supply chamber 102 in a substantially horizontal direction (in the direction of arrow I or J in FIG. 41) 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. 41, 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. 41) 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 conveying direction of the toner T by the stirring screw-shaped portion 108 a is opposite between the outside and the inside in the axial direction across the return port 107, and a conveying force is applied to the toner T toward the return port 107. Therefore, the toner T is collected from both sides in the axial direction below the return port 107 and pushed up in a mountain shape. As a result, when the 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 is returned to the toner storage chamber 101. Specifically, the toner T pushed up in a mountain shape at the return port 107 is returned from the toner 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. 39 as indicated by an arrow in FIG. 39 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 photoreceptor 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, the 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 area and is developed. For the developing electric field, an AC bias is used so that the voltage of the toner T in the direction of the photoconductor 2 and the voltage of returning 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.

  Also in the developing device 4 of the second embodiment, the configuration including the characteristic portions of the present invention with respect to the developing roller 42 and the doctor blade 45 described in the first embodiment can be applied.

  The developing device 4 of each embodiment described above carries the toner T, which is a developer, on the surface, moves the surface endlessly, and develops in the developing area α facing the photoconductor 2 that is a latent image carrier. A developing roller 42 is provided as a developer carrier for supplying the toner T to the latent image on the surface and developing it. The developing roller 42 is formed in a substantially cylindrical shape. A free end side of a plate-like member supported by a blade folder 45c, one end of which is a support member, comes into contact with the surface of the developing roller 42, and a doctor blade 45 which is a regulating member that regulates the amount of toner T toward the developing region α. Have Furthermore, the surface of the developing roller 42 is provided with an uneven shape. In such a developing device 4, the material of the doctor blade 45 at least in contact with the surface of the developing roller 42 is metal. If the material of the doctor blade 45 is a metal, it has a certain degree of rigidity. Therefore, the possibility that the doctor blade 45 bites into the recess 42b of the developing roller 42 due to its elasticity is less than that of a resin such as rubber, and the toner T in the recess 42b is scraped off. Therefore, the transport amount of the toner T by the developing roller 42 can be stabilized.

  Further, in the developing device 4 of each embodiment, the doctor blade 45 that is a restricting member is in contact with the surface of the developing roller 42 that is a developer bearing member at the free end side. Thus, the toner T present on the top surface 42t of the convex portion 42a can be worn out, and only the toner T present in the concave portion 42b is conveyed to the developing region α, so that the amount of toner conveyed to the developing region α is stable. To do.

In the developing device 4 of each embodiment, the extension surface of the facing surface 45b and the extension surface of the tip surface 45a on the free end side of the tip end portion on the free end side of the doctor blade 45 that is a restricting member intersect each other. The edge portion, which is a portion, or the vicinity thereof is in contact with the surface of the developing roller 42. Here, the facing surface 45 b is a surface facing the developing roller 42 in the doctor blade 45. By contacting the edge portion or the vicinity thereof, the toner amount on the surface of the developing roller 42 can be set to a desired amount corresponding to the volume of the recess 42b, and the transport amount of the toner T by the developing roller 42 can be stabilized.
Further, in the developing device 4 of each embodiment, the material of the portion that contacts the developing roller 42 that is the developer carrying member of the doctor blade 45 that is the regulating member is a material whose hardness is lower than the material of the surface of the developing roller 42. is there. As a result, the action of scraping the doctor blade 45 occurs, and the sticking of the toner T to the doctor blade 45 is easily eliminated.

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)
A developer such as toner T is carried on the surface, the surface moves endlessly, and a latent image on the surface of the latent image carrier is developed in a development area such as a development area α facing the latent image carrier such as the photosensitive member 2. A developer carrier such as a developing roller 42 that supplies the developer and develops, and a regulating member such as a doctor blade 45 that regulates the amount of developer that contacts the surface of the developer carrier and moves toward the development region. In a developing device such as the developing device 4 having a concave and convex shape such as a concave portion 42b and a convex portion 42a on the surface of the developer carrying member, the width of the developer carrying member in the width direction perpendicular to the surface movement direction of the developer carrying member is Insulation such as alumite coating on the outside of the developer supply area (toner non-supply area 420e, etc.) such as the toner supply area 420d for supplying the developer facing the latent image on the surface of the latent image carrier on the surface A coating layer is provided.
According to this, as described in the first embodiment, the developer including the intermediate region such as the groove forming intermediate portion 420c in which the processing accuracy of the concavo-convex shape is unstable and an unintended sharp protrusion may be formed. An insulating coating layer can be provided in a region outside the supply region. If a sharp protrusion is formed, abnormal discharge is likely to occur between the protrusion and the surface of the latent image carrier, but by covering the region where this protrusion can be formed with an insulating coating layer, Even if sharp protrusions are formed, the occurrence of abnormal discharge can be suppressed. Therefore, it is possible to suppress the occurrence of abnormal discharge between the region on the outer side in the width direction with respect to the developer supply region of the developer carrier and the latent image carrier.
(Aspect B)
In the aspect A, the surface of the developer carrying member such as the developing roller 42 is not uneven, such as a groove forming portion 420a where a desired unevenness is formed, and a non-groove forming portion 420b such as a non-grooved portion 420b where no unevenness is formed. In addition, there is an intermediate region, such as a groove forming intermediate portion 420c, in which the depth of the concave portion is shallower than the concave / convex forming region, between the concave / convex forming region and the concave / convex forming region. An insulating coating layer is provided.
According to this, as described in the first embodiment, the insulating coating layer is formed in an intermediate region such as the groove forming intermediate portion 420c where the processing accuracy of the concavo-convex shape is unstable and an unintended sharp protrusion may be formed. Can be provided. Thus, by covering the intermediate region with the insulating coating layer, it is possible to suppress the occurrence of abnormal discharge even if an unintended sharp protrusion is formed in the intermediate region.
(Aspect C)
In the aspect A or B, the developer carrying member such as the developing roller 42 is opposed to the latent image carrying member such as the photosensitive member 2 in a non-contact state in the developing region such as the developing region α. It is the structure arranged like this.
According to this, as described in the first embodiment, the developing method jumps the developer such as toner T from the developer carrier to the latent image carrier, and between the developer carrier and the latent image carrier. Occurrence of abnormal discharge can be suppressed.
(Aspect D)
In any of the aspects A to C, an alumite coat is used as the insulating coating layer.
According to this, as described in the first embodiment, a developer carrier such as the developing roller 42 having high durability can be realized, and the occurrence of abnormal discharge can be suppressed over time.
(Aspect E)
In any of the aspects A to D, the developer carrier such as the developing roller 42 is made of a metal such as aluminum.
According to this, as described in the first embodiment, when the developer carrying member is made of metal, electric discharge is likely to occur due to a pointed portion in an intermediate region such as the groove forming intermediate portion 420c. The occurrence of discharge can be suppressed by providing an insulating coating layer such as a coat.
(Aspect F)
In any of the aspects A to E, the surface of the developer carrying member such as the developing roller 42 is subjected to a plating process, and then an insulating coating layer such as an alumite coat is coated.
According to this, as described in the first embodiment, it is possible to suppress the occurrence of abnormal discharge due to energization through the plating.
(Aspect G)
In any of the aspects A to F, a non-magnetic or magnetic one-component developer is used as the developer for the toner T or the like.
According to this, as described in the first embodiment, the developing device can be simplified and the cost can be reduced.
(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 copier 500 having the latent image forming unit and the developing unit for developing the electrostatic latent image into a toner image, the developing unit is any one of modes A to G. Use a developing device.
According to this, as described in the first embodiment, it is possible to suppress the occurrence of discharge between the latent image carrier and the developer carrier such as the developing roller 42, which is caused by the discharge. It is possible to suppress the occurrence of abnormal images.
(Aspect I)
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 configured to be detachably integrated with the image forming apparatus main body as a unit held by a common holder, the developing device according to any one of the aspects A to G is provided. Use.
According to this, as described in the first embodiment, a developing device capable of suppressing a decrease in image density after use over time while suppressing the occurrence of discharge in the developing region is provided with a process cartridge. The other members to be configured can be removed from the apparatus main body. Therefore, it is possible to improve the exchangeability of the developing device capable of suppressing the occurrence of abnormal images and image density reduction due to discharge.

Process cartridge 2 Photoconductor 2a Image area 2b Non-image area 3 Charging member 4 Developing device 5 Photoconductor cleaning device 6 Exposure device 7 Intermediate transfer belt 8 Primary transfer roller 9 Secondary transfer roller 9a Secondary transfer counter roller 11 Transfer belt cleaning device 12 fixing device 41 developing casing 42 developing roller 42a convex portion 42b concave portion 42f surface layer 42g base material 42t top surface 43 toner accommodating portion 43b bottom surface portion 43s side wall surface portion 44 supply roller 45 doctor blade 45a front end surface 45b opposing surface 45c blade folder 45e edge Portion 46 paddle 47 inlet seal 48 supply screw 49 toner remaining amount sensor 50 step portion 55 toner supply port 56 opening portion 59 side seal 100 printer portion 101 toner storage chamber 102 toner supply chamber 106 toner conveyance member 106a conveyance screen Shaped part 106b Conveying plate shaped part 107 Return port 108 Toner stirring member 108a Stirring screw shaped part 108b Stirring plate shaped part 109 Static elimination seal 110 Partition member 111 Supply port 142 Developing bias power supply 144 Supply bias power supply 145 Doctor bias power supply 200 Feeding part 300 Scanner unit 400 Toner bottle 411 Upper case 412 Middle case 412s Side wall portion 413 Lower case 420 Developing roller cylindrical portion 420a Groove forming portion 420b Non-groove forming portion 420c Groove forming intermediate portion 420d Toner supply region 420e Toner non-supply region 421 Developing roller shaft 422 Spacer 440 Supply roller cylindrical portion 441 Supply roller shaft 450 Blade member 451 Rivet 452 Base portion 454 Pin hole 454a Main reference hole 454b Secondary reference hole 455 Doctor fixing screw 460 Paddle blade 46 Paddle shaft 480 feed screw blade section 481 supply screw shaft 500 copier 600 printer L1 first groove L2 second groove P transfer sheet Q contact position Q1 initial contact position T toner W1 pitch X1 moving distance α developing region β feed nip

JP 2008-292594 A JP 2010-152070 A

Claims (9)

A developer carrying member that carries the developer on the surface, moves the surface endlessly, and supplies the developer to the latent image on the surface of the latent image carrying member in a developing region facing the latent image carrying member;
A regulating member that regulates the amount of developer that contacts the surface of the developer carrying member and moves toward the developing region;
In the developing device having a concavo-convex shape on the surface of the developer carrying member,
In a width direction orthogonal to the surface movement direction of the developer carrier, a developer supply region for supplying developer on the surface of the developer carrier opposite to the latent image on the surface of the latent image carrier. A developing device comprising an insulating coating layer in an outer region. The developing device according to claim 1,
The surface of the developer carrying member has a concavo-convex formation region where desired concavo-convex is formed and a concavo-convex non-formation region where no concavo-convex is formed, and further, between the concavo-convex formation region and the concavo-convex non-formation region. In addition, there is an intermediate region in which the depth of the recess is shallower than the uneven formation region,
A developing apparatus comprising the insulating coating layer in the intermediate region. The developing device according to claim 1 or 2,
The developing device, wherein the developer carrying member is arranged so as to face the latent image carrying member in a non-contact state with a certain distance in the developing region. In the developing device according to any one of claims 1 to 3,
A developing apparatus using an alumite coat as the insulating coating layer. In the developing device according to any one of claims 1 to 4,
The developing device, wherein the developer carrying member is made of metal. The developing device according to any one of claims 1 to 5,
The developing device according to claim 1, wherein the surface of the developer carrying member is plated and then coated with the insulating coating layer. The developing device according to any one of claims 1 to 6,
A developing apparatus using a non-magnetic or magnetic one-component developer as the developer. 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 1 as the developing unit. 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 one 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 1 as the developing means.

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