JP2013164540A - Developing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain developability even when the number of sheets fed to a developing device increases, or the developing device is used in a high-speed rotation.SOLUTION: A developing device 4 comprises: a metallic developing roller 42 that is arranged opposite to a photoreceptor 2 carrying an electrostatic latent image while being separated from the photoreceptor 2 by a predetermined distance, includes a plurality of protrusions 42a that are periodically arranged and recesses 42b that surround the protrusions 42a, and carries one-component developer; and a metallic doctor blade 45 that contacts a developer carrier to regulate the amount of one-component developer attached to the developer carrier. Only the recesses 42b of the developing roller 42 have a synthetic resin layer 51 formed thereon to which a charge control agent is added.

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 using the developing device.

  In recent years, color printers using one-component development have been increasingly demanded for higher speeds. FIG. 22 is a schematic diagram showing a conventional image forming apparatus. The image forming apparatus 600 has a configuration in which a color image is formed on an intermediate transfer member and transferred onto a transfer sheet by a secondary transfer unit. The image forming apparatus 600 includes a configuration in which a plurality of colors, for example, four color image forming units 611, 612, 613, and 614 are arranged in parallel to form a color image. In some cases, the image forming apparatus employs a configuration in which the image is directly transferred from a photosensitive member onto a transfer sheet.

  In such an image forming apparatus 600, the development unit and the photosensitive unit are often integrated so that the user can easily replace the image forming unit. By making the developing unit vertically long, a necessary amount of toner can be accommodated and the apparatus width in the horizontal width direction in the figure can be shortened. Here, the image forming units 611, 612, 613, and 614 have the same structure except that the toner colors are different.

  In the image forming apparatus 600, in the image forming units 611, 612, 613, and 614, the photosensitive member 621 is charged by the charging roller 622, and then exposed by a writing optical system (not shown) to form a latent image, and one-component development A toner image of a predetermined color is formed by the apparatus 630 and transferred to the intermediate transfer belt 623. The toner images of the respective colors are superimposed on the intermediate transfer belt 623, transferred onto a transfer paper conveyed by a paper conveyance unit (not shown) by the secondary transfer unit 624, and the toner image is fixed by the fixing unit 625.

  FIG. 23 is a sectional view showing a one-component developing device of the image forming apparatus shown in FIG. A predetermined amount of non-magnetic one-component toner is accommodated in a developing container 631 of the one-component developing device 630, and the toner is supplied to a supply roller 632 made of a foam disposed below the developing unit. The supply roller 632 and the development roller 633 rotate at a predetermined linear speed ratio in the direction of the arrow in the drawing, and supply toner from the supply roller 632 to the development roller 633. As the developing roller 633, a roller having an elastic layer formed of rubber or the like, or a roller having a metal surface blasted to be rough is generally used. The toner adhering to the developing roller 633 is frictionally charged with the developing roller at the nip portion between the regulating blade 634 and the developing roller 633 to be charged with a negative polarity, and after passing through the nip portion, a necessary amount of toner is developed on the developing roller 633. A toner layer is formed. The developing roller 633 rotates at a predetermined linear velocity ratio η with respect to the linear velocity of the photoconductor, with or without contact with the photoconductor 621, and supplies toner to the electrostatic latent image on the photoconductor 621 to form a toner image. .

  Recently, there is an increasing demand for higher image quality in a color forming apparatus using a one-component developing device that is small and low in cost. For this reason, even in a one-component developing device, it is necessary to improve image quality by reducing the particle size of toner. To reduce the particle size of the toner, the mainstream is to reduce the particle size by using a polymerized toner, but a pulverized toner having a particle size of 6 μm or less has been put into practical use. However, the toner having a small particle size easily forms an aggregate due to stress, and the phenomenon that the aggregate is generated in the nip portion of the regulating blade and the developing roller and stays in the nip portion, and the toner is likely to be fixed to the blade.

  FIG. 24 is an enlarged cross-sectional view showing a developing roller surface state of a conventional developing device. The developing roller 640 is made of metal and includes fine irregularities due to the lubricating fine particles periodically arranged on the surface, that is, a plurality of convex portions 641 and a concave portion 642 surrounding the convex portions 641.

  In the developing device 4, the installation condition of the regulating blade 634 is set to a condition for removing the toner adhering to the convex surface. FIG. 25 is a cross-sectional view showing a toner removal state. When the toner of the convex portion 641 is removed by the regulating blade 634, the toner T remains only in the concave portion 642 where the regulating blade does not enter as shown in FIG.

  In the developing roller 640, the toner adhering to the convex portion 641 in contact with the regulating blade 634 is removed, so that toner aggregates do not stay and the toner in the concave portion 642 is not subjected to the strong pressure of the regulating blade 634. Therefore, the toner does not adhere to the blade.

  As such a developing device, Patent Document 1 discloses that the developing roller has a cylindrical shape or a cylindrical shape in order to improve the toner flying property from the developing roller to the photosensitive member even when the toner particle size is reduced. A substrate having a concavo-convex portion formed on an outer peripheral surface, and a surface layer formed on the outer peripheral surface of the substrate and including lubricating fine particles having lubricity with respect to a metal and a toner; Discloses a surface formed on the opposite surface so that the toner can be carried while reducing the contact area.

  However, the developing device described in Patent Document 1 has a problem in that the surface layer of the convex portion 652 is worn by use and developability is deteriorated. FIG. 26 is a sectional view showing a state in which the surface layer of the developing roller is worn. A convex portion 652 and a concave portion 653 are formed on the outer peripheral surface of the base 651 of the developing roller 650, and a surface layer 654 having a thickness dimension d0 is formed. However, the surface layer 654 formed on the convex portion 652 is in contact with the regulating blade being pressed, and thus wears when the number of sheets to be passed through the apparatus increases or when rotated at high speed.

  Thereby, the surface layer 654 changes from the state C (broken line) in FIG. 26 to the state D (solid line), and the thickness dimension of the surface layer 654 decreases from d0 to d1. On the other hand, since the surface layer 654 formed in the concave portion 642 is not worn and remains d0, the depth of the groove formed by the convex portion 652 and the concave portion 653 decreases (D0 to D1 in FIG. 26). For this reason, the volume of the space for forming the toner layer is reduced, the amount of toner transport is reduced, and the developability is lowered.

  The present invention has been made in view of the above points, and provides a developing device and an image forming apparatus capable of maintaining developability even when the number of sheets passing through the apparatus is increased or when the apparatus is used at a high speed. With the goal.

  A developing device according to the present invention is arranged to face an image carrier that carries an electrostatic latent image, and includes a plurality of periodically arranged convex portions and concave portions surrounding the convex portions, and includes a one-component development. In a developing device, comprising: a metallic developer carrying member that carries a developer; and a metal blade that regulates the amount of a one-component developer that contacts and adheres to the developer carrying member. A synthetic resin layer in which a charge control agent is added only to the concave portion is formed.

  According to the present invention, since the convex portion does not wear, even if the number of sheets passing through the apparatus increases, it is possible to prevent the developability from deteriorating by keeping the amount of toner adhered to the developer carrier constant. it can.

1 is a schematic configuration diagram of a developing device according to an embodiment. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. FIG. 3 is a perspective explanatory view of the developing device. FIG. 3 is a perspective explanatory view of the developing device. FIG. 2 is an explanatory cross-sectional view of the developing device. FIG. 2 is a perspective view showing a part of the developing device in a sectional view. FIG. 6 is an enlarged perspective view of the vicinity of one end of the developing device in which a lower case is not shown. FIG. 8 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 7. FIG. 6 is an enlarged perspective view of the vicinity of the other end of the developing device, with the lower case not shown. FIG. 10 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 9. It is a perspective explanatory view of the developing roller of the developing device according to the embodiment. It is a side view of the developing roller. It is explanatory drawing of the surface shape of the developing roller, (a) is a schematic diagram of the whole developing roller, (b) is an enlarged view of a part of the surface of the developing roller. FIG. 14 is a cross-sectional view corresponding to the line BB in FIG. 13 showing the state of the synthetic resin layer of the developing roller. FIG. 3 is a perspective explanatory view of a supply roller of the image forming apparatus according to the embodiment. It is a side view of the supply roller of the developing device. FIG. 6 is a perspective explanatory view of a doctor blade of the developing device. It is a side view of the doctor blade. It is a perspective view of a paddle of the developing device. It is a side view of the paddle. FIG. 3 is an enlarged explanatory view of a doctor portion of the developing device in a state where the doctor blade is applied to the stomach. It is a schematic diagram showing a conventional image forming apparatus. FIG. 24 is a cross-sectional view showing a one-component developing device of the image forming apparatus shown in FIG. 23. 6 is an enlarged cross-sectional view illustrating a state of a developing roller surface of a developing device described in Patent Document 1. FIG. FIG. 26 is a cross-sectional view corresponding to the line AA in FIG. 25 showing a toner removal state. It is sectional drawing which shows the state which the surface layer of the developing roller was worn out.

  Next, a developing device and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, the image forming apparatus according to the embodiment will be described as a copying machine 500. FIG. 2 is a schematic configuration diagram of the image forming apparatus according to the 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) attached on the printer unit 100.

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

  The process cartridge 1 is a unit that integrally supports a photosensitive member 2 that is a latent image carrier, a charging member 3 that is a charging unit, a developing device 4 that is a developing unit, and a photosensitive member cleaning device 5 that is a cleaning unit. It has a configuration that has a shape. 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 contact with the surface of the photoconductor 2 with pressure applied, 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. The process cartridge 1 uses a roller-shaped charging member 3 that is in contact with the surface of the photoreceptor 2 as charging means. The charging means is not limited to this, and a non-contact charging method such as corona charging may be used.

  The exposure device 6 exposes the surface of the photoconductor 2 based on image information of an original image read by the scanner unit 300 or image information from an external device such as a personal computer, and electrostatically exposes the surface of the photoconductor 2. A 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 respectively form yellow, cyan, magenta, and black toner images 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 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 photoconductor 2. By forming a primary transfer electric field between the photoreceptor 2 and the primary transfer roller 8, the toner image formed on the surface of the photoreceptor 2 is transferred to the surface of the intermediate transfer belt 7. One of the plurality of stretching rollers around 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 drawing. 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 opposing roller 9 a that is one of the stretching rollers. A secondary transfer roller 9 is disposed at a position facing the transfer belt 7 and a secondary transfer nip is formed with the intermediate transfer belt 7. 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. A full-color image formed on the surface of the intermediate transfer belt 7 when the transfer paper P, which is a transfer material fed from the paper supply unit 200 and conveyed in the direction of arrow C in FIG. Then, the image is transferred onto the transfer paper P by a secondary transfer electric field formed between the secondary transfer roller 9 and the secondary transfer counter roller 9a.

  The fixing device 12 is disposed on the downstream side of the transfer direction of the transfer paper P with respect to the secondary transfer nip. 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 copied. Output to the outside of the 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, toner bottles 400 (Y, M, C, and K) that store toner of respective colors are disposed above the intermediate transfer belt 7 so as to be detachable from 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. 1 is a schematic configuration diagram of a developing device according to the embodiment. FIG. 1 corresponds to a cross-sectional view as viewed from the back side in FIG. 3 and 4 are perspective explanatory views of the developing device, and the developing device 4 is viewed from obliquely 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 forms 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 that is a developer carrier and the upper case 411.

  FIG. 5 is a cross-sectional explanatory view of the developing device 4 viewed from the same direction as FIG. 1, and FIG. 6 is an enlarged perspective view of a part of the developing device 4, and a part thereof is a ZX cross-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 toner from the inside to the outside (developing area α facing the photoconductor). In the developing device 4, the doctor blade 45 is made of a metal plate material, and is arranged so that the tip portion thereof contacts the developing roller 42.

  FIG. 7 is an enlarged perspective view of the vicinity of one end (the rear end in FIG. 2) of the developing device 4 in which the lower case 413 is not shown, and FIG. 8 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. 9 is an enlarged perspective view of the vicinity of the other end (front end in FIG. 2) of the developing device 4 in which the lower case 413 is not shown, and FIG. 10 is a view showing development from the state of FIG. FIG. 4 is an enlarged perspective view of the developing device 4 in which illustration of a roller 42 is omitted.

  In the developing device 4, the supply roller 44 rotates in the direction of arrow C in FIG. 1 (clockwise direction in FIG. 1) and moves on the surface, so that the toner T in the toner accommodating portion 43 faces the developing roller 42. Then, the toner is supplied to the surface of the developing roller 42. The developing roller 42 carries the supplied toner on the surface, rotates in the direction of arrow B in FIG. 1 (clockwise direction in FIG. 1), and moves on the surface, thereby removing the toner on the developing roller 42. The toner is transported to a portion facing the doctor blade 45 that is a regulating blade that regulates to a predetermined amount. The toner regulated to a predetermined amount at the portion facing the doctor blade 45 reaches the developing area α which is the portion facing the photoreceptor 2 by the rotation of the developing roller 42. In the supply nip β, the surface of the supply roller 44 moves from below to above, and the surface of the developing roller 42 moves from above to below.

  In the developing area α, the toner T on the surface of the developing roller 42 is generated according to the developing electric field formed by the potential difference between the developing bias applied from the developing bias power source 142 to the developing roller 42 and the latent image on the surface of the photoreceptor 2. Moves to the surface of the photoreceptor 2. As a result, the toner adheres to the electrostatic latent image portion on the surface of the photoreceptor 2 and development is performed. The photoreceptor 2 rotates in the direction of arrow D in FIG. 1 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.

  Further, the developing bias power source 142 includes a first voltage for directing the toner from the developing roller 42 to the photosensitive member 2 and developing roller from the photosensitive member 2 to the developing roller for developing the latent image by the toner conveyed to the developing region α. An alternating voltage having a second voltage for directing the toner to 42 is applied to the developing roller 42.

  Although details will be described later, the surface of the developing roller 42 has a regular uneven shape in which the height of the convex portion 42a and the depth of the concave portion 42b are substantially constant. Further, a synthetic resin layer 51 is coated on the recess 42b formed in the developing roller 42 (see FIG. 14). The toner T on the surface of the developing roller 42 that does not contribute to development in the developing area α and passes through the developing area α is collected by the supply roller 44 at the supply nip β, and the surface of the developing roller 42 is reset.

  It is difficult to collect the toner T carried on the concave portions 42b regularly formed on the surface of the developing roller 42. Then, when the toner T that has passed through the developing region α passes through the supply nip β and remains carried by 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, 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 is increased, and the recovery performance of the supply roller 44 at the supply nip β can be improved. Therefore, it is possible to suppress the toner from being held on the developing roller 42, to suppress the toner from adhering to the surface of the developing roller 42, and development caused by the developer adhering to the surface of the developer carrying member. Occurrence of density unevenness at the time can be suppressed.

  Further, as shown in FIG. 1, 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. It is above the surface of the toner T. A region on the downstream side of the supply roller 44 in the surface movement direction with respect to the supply nip β (hereinafter referred to as a supply nip downstream region) is located above the surface of the toner T. If the toner is filled in the downstream area of the supply nip, the toner filled in the downstream area of the supply nip prevents new toner from entering the downstream area of the supply nip, and the developing roller in the supply nip β There is a possibility that the recovery efficiency of the toner from 42 may be lowered.

  On the other hand, as shown in FIG. 1, in the developing device 4 according to the present embodiment, the downstream area of the supply nip is above the surface of the toner T, and therefore, the downstream area of the supply nip is filled with toner. In addition, the toner existing in the downstream area of the supply nip is not hindered from the recovery of the toner from the developing roller 42 in the supply nip β, so that the toner can be recovered efficiently and the toner resetting property Can be improved.

  Furthermore, as shown in FIG. 22, the contact state of the doctor blade 45 with the surface of the developing roller 42 is more likely to wear the toner T present on the top surface of the convex portion 42a when the tip is in contact. preferable. The tip contact refers to a state in which the doctor blade 45 is brought into contact with the developing roller 42 in an edge contact state. Here, the edge contact is a state in which an edge portion forming a ridge line between the facing surface 45b and the front end surface 45a of the doctor blade 45 is in contact with the surface (convex surface) of the developing roller 42. Here, in the edge portion forming the ridge line, the ridge line may be rounded or chamfered.

The vicinity of the place where the surface which extended the opposing surface of the doctor blade and the front end surface intersects is shown. Specifically, the corner on the developing roller side of the free end of the flat doctor blade (which may be rounded or chamfered) comes into contact with the convex portion of the developing roller. That's fine.
Here, there is a method in which the blade is bent and the bent portion is brought into contact with each other. However, as for the effect of scraping off the toner, it is more desirable that the tip on the free end side is in contact with the above.

  Next, the developing roller 42 will be described. FIG. 11 is a perspective view of the developing roller 42, and FIG. 12 is a side view of the developing roller 42. 13 is an explanatory view of the surface shape of the developing roller 42, FIG. 13A is a schematic diagram of the entire developing roller 42, and FIG. 13B is a developing roller 42 shown in FIG. 13A. It is an enlarged view of a part of the surface.

  The developing roller 42 has a configuration in which a developing roller cylindrical portion 420 that carries toner on the surface thereof is provided on the developing roller shaft 421, and the developing roller shafts in the vicinity of both axial end portions that are axially outside the developing roller cylindrical portion 420. 421 includes a spacer 422. 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. . Both ends in the axial direction of the developing roller shaft 421 of the developing roller 42 are rotatably attached to the side wall portion 412s of the middle case 412. A part of the surface of the developing roller 42 is exposed to the outside of the developing device 4 from the opening 56, and the developing roller 42 is moved from the lower side to the upper side to convey the toner so that the toner is conveyed in FIG. It rotates in the direction of arrow B.

  Further, in the developing roller 42, the distance between the surface of the developing roller cylindrical portion 420 and the surface of the photosensitive member 2 in the developing region α is obtained by the spacers 422 provided in the vicinity of both ends in the axial direction contacting the surface of the photosensitive member 2. (Development gap) is kept constant.

  The developing roller 42 is made of an aluminum alloy, an iron alloy, or the like for general droplets. The developing device 4 according to this embodiment uses an iron-based material such as STKM. As shown in FIG. 13A, 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 the 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. In the developing device 4 according to the present embodiment, so-called rolling processing is used as the concavo-convex processing, and the convex portion 42a is formed surrounded by the spiral first groove L1 and second groove L2 having different winding directions. . In the developing roller 42 of the present embodiment, 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 of the convex portion 42a is 40 [μm]. Furthermore, the depth of the concave portion, which is the height from the concave portion 42b to the top surface of the convex portion 42a, was set to 10 [μm]. The values of the pitch width W1, the axial length W2 of the top surface, and the depth of the recess are examples, and are not limited to these values.

  The surface of the developing roller 42 is preferably made of a material that normally charges the toner. Even when a low-charged toner is produced by 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. It can be reduced and the image density is stabilized.

  In non-contact development, if the adhesion force between the toner and the developing roller increases, the developability deteriorates unless the amplitude of the AC voltage is increased. However, if the amplitude is increased, the potential of the non-image area of the photoreceptor and the maximum development bias are reduced. The difference from the potential becomes larger, and discharge occurs at that portion, resulting in image noise. Therefore, it is necessary to reduce the adhesion between the toner and the developing roller. When the charge amount of the toner is high, the adhesion force of the toner to the developing roller due to the Coulomb force increases, and the developability tends to deteriorate. Therefore, for example, when the average toner Q / M is set to about −30 (μC / g) to −40 (μC / g), desired developability can be obtained. For this reason, it is difficult to obtain desired developability.

  Therefore, in the developing device 4 according to this embodiment, the surface of only the recess 42b is coated with the synthetic resin layer 51. 14 is a cross-sectional view corresponding to the line BB in FIG. 13 showing the state of the synthetic resin layer of the developing roller. In the embodiment, since the metal portion of the developing roller 42 is made of an iron-based material such as STKM, it hardly wears due to contact with the doctor blade 45. Further, since the synthetic resin layer 51 is not worn, even when the developing roller 42 is used at high speed rotation, the depth of the groove portion does not change and the toner conveyance amount does not decrease. The synthetic resin layer 51 is obtained by adding a charge control agent and changing the type and amount thereof and optimizing it in accordance with the chargeability of the toner. As a material for forming the synthetic resin layer, for example, a polycarbonate resin or a fluorine resin is suitable. Examples of the charge suppressing agent include a surfactant system, an inorganic material system, and a polymer system.

  When a surface layer is provided on the convex portion 42 a on the developing roller 42, the surface is worn by the regulating blade 634. On the other hand, since the concave portion is not worn, the depth of the groove portion is reduced, the volume of the space where the toner layer is formed is reduced, the toner transport amount is lowered, and the developability is lowered. In this embodiment, such a situation can be prevented.

  Thus, in the present embodiment, the developing roller 42 is formed of an iron-based material such as STKM, with the convex portion 42a being harder than the doctor blade 45 (blade member 450). As a result, the convex portion 42a on the surface of the developing roller 42 is hard to be scraped by the doctor blade 45, and the volume of the concave portion 42b surrounded by the convex portion 42a and the doctor blade 45 is unlikely to change, and the M / A value (unit on the developing roller surface) The toner carrying amount per area is stable.

  The depth of the groove formed by the convex portion 42a of the developing roller 42 and the synthetic resin layer 51 is desirably larger than the weight average particle diameter of the toner T to be used. Since the toner T having an average size is accommodated in the recess 42b, it is difficult to select the particle size, and the M / A value (the amount of toner carried per unit area on the developing roller surface) with time is stabilized. .

  Here, when the synthetic resin layer 51 is provided on the developing roller 42, a counter charge may occur, and a phenomenon such as a decrease in developability and an afterimage may occur. In order to cope with this, it is desirable to add conductive fine particles to the synthetic resin layer 51. This lowers the resistance of the resin and makes it easier for the counter charge to flow into the metal part.

  Further, in the developing device 4 according to this embodiment, the photosensitive member 2 and the developing roller 42 are not in contact with each other, and the toner is placed on the photosensitive member facing the convex portion on the developing roller by the electric field of the latent image by making a linear speed ratio. Since the developing roller rotates with the photosensitive member at a linear speed ratio η, the unevenness of the developing roller does not cause pitch unevenness unless the pitch of the unevenness of the developing roller is too large.

  Here, the granularity of the image and the dot reproducibility can be improved by reducing the toner particle diameter. However, when the toner has a small particle size, the contribution of non-electrostatic adhesion tends to increase in addition to the adhesion between the toner and the developing roller due to the Coulomb force described above. Even if the charge amount of the toner is set to a predetermined value, if the non-electrostatic adhesive force is large, the developability is deteriorated when the toner has a small particle diameter. In the developing device 4 according to this embodiment, the material of the synthetic resin layer formed on the developing roller 42 can be selected to reduce the non-electrostatic adhesion force. Even if a toner having a small particle diameter is used, a decrease in developability can be prevented.

  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 thereof, and the cylindrical foam material becomes a supply roller cylindrical portion 440 that carries toner on the surface thereof. .

  The supply roller 44 is configured to be rotatable about a supply roller shaft 441, and the shaft is rotatably attached to the side wall portion 412 s of the middle case 412. The supply roller 44 is disposed such that a part of the outer peripheral surface of the supply roller cylindrical portion 440 is in contact with the outer peripheral surface of the developing roller cylindrical portion 420 of the developing roller 42 at the supply nip β. As shown, the supply roller shaft 441 is disposed above the developing roller shaft 421. Further, as described above, the supply roller 44 rotates so that the surface moves in the direction opposite to the surface movement direction of the developing roller 42 at the supply nip β that is a portion facing the developing roller 42. Further, as shown in FIG. 1, the developing device 4 is arranged such that the position of the supply nip β is located above the contact position of the doctor blade 45 with the developing roller 42.

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

  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 toner resetting property in the concave portion 42b can be improved. Note that if the amount of biting of the supply roller 44 with respect to the developing roller 42 is too large relative to the height of the convex portion 42a, the toner will be pushed into the concave portion 42b and cause aggregation, so the amount of biting will not be too large. It is necessary to set as follows.

  The foam material used for the supply roller cylindrical portion 440 of the supply roller 44 is set to an electric resistance value of 103 to 1014 [Ω]. A supply bias is applied to the supply roller 44 by a supply bias power supply 144 to assist the operation of pressing the toner precharged at the supply nip β against the developing roller 42. The supply roller 44 rotates in the clockwise direction in FIGS. 1 and 5 to apply and supply the developer attached to the surface to the surface of the developing roller 42.

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

  Next, the doctor blade 45 will be described. FIG. 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 FIG. 5 to FIG. 10, the doctor blade 45 is provided in the middle case 412 that is located inside the lower case 413 below the developing roller 42. The doctor blade 45 includes a blade member 450 that is a thin plate-like metal 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 contact the developing roller 42. The contact state of the blade member 450 with respect to the developing roller 42 may be either a tip contact state in which the tip contacts or a stomach contact state in which a surface portion on the base side from the tip contacts. However, in the state where the tip is applied, the toner present on the top surface of the convex portion 42a can be worn out, and only the toner present in the concave portion 42b is transported to the developing region α, whereby the amount of toner transported to the developing region α. Is more preferable because it is stable.

  The blade member 450 of the doctor blade 45 is fixed to the pedestal portion 452 with 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, and one is a perfect circular main reference hole 454 a, and the other is an elliptical secondary reference hole 454 b having a major axis in the direction of the main reference hole 454 a.

  By inserting a pin (not shown) into the main reference hole 454a, the position of the pedestal 452 with respect to the main body of the developing device 4 is determined and supported by the sub reference hole 454b. The blade member 450 is fixed to the developing device 4 by fixing the pedestal portion 452 to which the blade member 450 is fixed to the developing device 4 main body (inner case 412) with a doctor fixing screw 455.

  The blade member 450 of the doctor blade 45 uses a metal leaf spring material such as SUS304CSP, SUS301CSP, or phosphor bronze, and the free end side is brought into contact with the surface of the developing roller 42 with a pressing force of 10 to 100 [N / m]. The toner passing under the pressing force is regulated to a predetermined amount and an electric charge is given by frictional charging. Further, a bias is applied to the blade member 450 from a doctor bias power source 145 in order to assist frictional charging.

  The blade member 450 of the doctor blade 45 is preferably made of a conductive material. 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.

  Further, as a voltage applied by the doctor bias power supply 145 to the blade member 450, a DC voltage is applied in a range of ± 200 [V] with respect to the alternating voltage applied to the developing roller 42. It is good also as a structure which controls the value of. As a result, it is possible to suppress fluctuations in the M / A value (toner carrying amount per unit area on the surface of the developing roller) due to environmental fluctuations.

  Next, the paddle 46 will be described. 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. A paddle 46 is rotatably attached to the developing casing 41 in the toner container 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 attached to the two flat portions, respectively. 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 so as to be parallel to the axial direction. 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 412 s of the middle case 412.

  In the paddle 46, the protrusion 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. 1 and 5, the bottom surface portion 43 b of the toner storage portion 43 is formed in an arc shape along the rotation direction of the paddle 46, and the paddle blades 460 are contacted with the rotation of the paddle 46 by the paddle blades 460. The bottom surface 43b is not caught.

  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 becomes horizontal in the direction toward the roller parallel to the X axis at a level equal to or slightly lower than the center of the paddle shaft 461, thereby forming the stepped portion 50.

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

  The step portion 50 is formed so as to extend in the longitudinal direction of the developing device 4 (Y-axis direction in the drawing) on a horizontal plane parallel to the XY plane. In the developing device 4 of the present 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 will be described. As shown in FIGS. 5 and 6, the supply screw 48 is a screw member including 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 supply screw shaft 481 is arranged so that the axial direction of the supply screw shaft 481 is parallel to the longitudinal direction of the developing device 4 (Y-axis direction in the drawing). Both axial ends of the supply screw shaft 481 are rotatably attached to the side wall portion 412s of the middle case 412.

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

  Next, the inlet seal will be described. As shown in FIGS. 5 and 7 to 10, a sheet member such as a mylar is attached to the edge portion of the upper case 411 that forms the opening 56 as the inlet seal 47 along the longitudinal direction. 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 disposed 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 rotational direction of the developing roller 42, and the downstream side in the rotational direction of the developing roller 42 is a free end, and the surface portion of the inlet seal 47 contacts the developing roller 42. It is arranged to do. 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 side seal will be described. As shown in FIGS. 7 to 10, 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 of the spacer 422 provided in the vicinity of both ends in the axial direction of the developing roller 42 and in an area where the axial end where the doctor blade 45 contacts the developing roller 42 overlaps. Yes. Such a side seal 59 prevents the toner from leaking from the end portion in the longitudinal direction of the opening 56 in the developing casing 41. A remaining toner sensor 49 provided in the middle case 412 detects the amount of toner in the toner storage unit 43.

  Next, the movement of toner in the developing device 4 will be described. As shown in FIG. 5, the toner replenished into the developing device 4 from the toner replenishing port 55 is supplied to the toner accommodating portion 43 by the supply screw 48 and stirred by the paddle 46. In addition, the toner is splashed in the direction of the developing roller 42 and the supply roller 44 by the paddle 46 and is transported. The toner supplied to the supply roller 44 is delivered to the surface of the developing roller 42 at a supply nip β where the supply roller 44 contacts the developing roller 42. Of the toner delivered to the surface of the developing roller 42, the amount of toner exceeding a predetermined amount conveyed to the developing area α is scraped off from the surface of the developing roller 42 by the doctor blade 45.

  The toner remaining on the surface of the developing roller 42 that has passed through the portion facing the doctor blade 45 is conveyed as it is by the surface movement method by the rotation of the developing roller 42 and is conveyed to the developing region α facing the photosensitive member 2. The toner that has passed through the development region α without being used for development passes through a position where the inlet seal 47 contacts, and is conveyed to the supply nip β that is a position facing the supply roller 44. The toner that reaches 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, toner used in the copying machine 500 according to the present embodiment will be described. As the toner used in the copying machine 500, a toner having high fluidity is used so as to be compatible with high-speed toner conveyance. Specifically, a toner having an accelerated aggregation degree of 40% or less is used. The accelerated aggregation degree is an index indicating the fluidity of the toner. Further, an average value of circularity defined by a value of (peripheral length of an equivalent circle having the same projected area / periphery length of individual particles) when an individual particle is projected on a plane having an average particle diameter of 6 μm or less as a toner. Use 0.95 or more. Since the synthetic resin layers 51 and 52 provided on the developing roller 42 have been selected to have a low non-electrostatic adhesion, toner having a small particle diameter can be used. A toner having such characteristics can be produced by a polymerization method advantageous for production.

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 ・ Uses three types of sieves with different mesh openings (for example, 75 [μm], 44 [μm], 22 [μm])
-Calculate from the remaining amount of toner at the time of sieving, and obtain the degree of aggregation by the following calculation.
{(Weight of toner remaining on upper screen) / (sample amount)} × 100
{(Weight of toner remaining on middle screen) / (sample amount)} × 100 × 3/5
{(Weight of toner remaining on lower screen) / (sample amount)} × 100 × 1/5
The total of the above three calculated values is defined as the heat aggregation degree [%].

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

  In this embodiment, toner having an average circularity of 0.95 or more (0.95 to 1.00 toner) is used. Here, 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 = L0 / L (1)
(L0: perimeter of a circle having the same projected area as the particle image, L: perimeter of the projected image of the particle)

When the average circularity is in the range of 0.95 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 photosensitive member 2 is small, so that the transferability is excellent.
When the average circularity is in the range of 0.95 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, thereby causing abnormal images. 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 measurement method, a surfactant, preferably an alkylbenzene sulfonate, is added in an amount of 0.1 to 0.5 [ml] in 100 to 150 [ml] of water from which impure solids have been removed in advance. In addition, 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 by the above apparatus with the dispersion concentration being 3000 to 10000 [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], and particularly preferably 6 [μm] or less. In this embodiment, a toner of 6 [μm] or less is used. 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 the jumping 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 the exemplary embodiment is obtained by crosslinking 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 is dispersed in an organic solvent in an aqueous solvent. It is a toner obtained by an extension reaction and is called a polymerized toner. Hereinafter, the constituent materials 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), and (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) and addition products thereof. 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.); 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) , Naphthalenedicarboxylic acid, etc.). 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 polyvalent carboxylic 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 between 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 reduced in pressure as necessary. The produced water is distilled off while obtaining a polyester having a hydroxyl group. 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 fixing property 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. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of amide with 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; Blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. 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.).

  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 the compound (B6) obtained by blocking the amino group of B1 to B5 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.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). 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] exceeds 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 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 (tetrahydrofuran etc.).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can 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 Ortho Troaniline 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, Toulouse 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, Thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone , 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, Indance Ren 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, Chrome Oxide, Pyridian, Emerald Green , Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% [%], preferably 3 to 10% [%] based on the toner.

  The colorant can also be used as a master batch combined with a resin. 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 resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax 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 salt or compound, tungsten simple substance or compound, fluorine activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. 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, sulfonate group, a carboxyl group, 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. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller 42 is increased, the developer fluidity is reduced, and the image density is reduced. Incurs a decline.

<Release agent>
As the release agent, a low melting point wax having a melting point of 50 to 120 [° C.] is more effectively used as a release agent in the dispersion with the binder resin between the fixing roller of the fixing device 12 and the toner interface. It works 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. The waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and 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, or may be added when dissolved and dispersed in an organic solvent.

<External additive>
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 −3 to 2 [μm], and particularly preferably 5 × 10 −3 to 0.5 [μm]. Moreover, it is preferable that the specific surface area by BET method is 20-500 [m2 / 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, quartz 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 hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using an average particle diameter of both fine particles of 5 × 10-2 [μm] or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even with the stirring and mixing in the developing device 4 performed to obtain the charge level, the fluidity imparting agent is not detached from the toner, and good image quality that does not cause firefly is obtained. Reduction is achieved.

  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 usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles. The aqueous medium may be water alone, or 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, perfluoroalkyl carboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctane sulfonic acid diethanolamide, N-propyl-N- ( 2-hydroxyethyl) Perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be given.

  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).

  In addition, examples of the cationic surfactant include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. , 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) ), MegaFuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), and Footgent F-300 (Neos Co., Ltd.).

  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 [%]. For example, 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], trade names are PB- 200H (manufactured by Kao), SGP (manufactured by Soken), technopolymer SB (manufactured by Sekisui Plastics), SGP-3G (manufactured by Soken), Micropearl (manufactured by Sekisui Fine Chemical)

  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, a spindle-shaped toner base particle can be prepared by removing the solvent. . When a dispersion stabilizer that is soluble in an acid or alkali such as calcium phosphate is used, the calcium phosphate is dissolved from the toner base particles by a method such as dissolving the calcium phosphate 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 applying strong agitation in the process of removing the organic solvent, the shape between the 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.

1: Process cartridge 2: Photoconductor (image carrier)
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 (developer carrier)
42a: convex portion 42b: concave portion 43: toner accommodating portion 43b: bottom surface portion 43s: side wall surface portion 44: supply roller 45: doctor blade 45a: leading end surface 45b: facing surface 200: paper feeding unit 300: scanner unit 400: toner bottle 500 : Copier (image forming device)

JP 2008-292594 A

Claims (7)

Metal development that is arranged opposite to an image carrier that carries an electrostatic latent image, and that has a plurality of periodically arranged convex portions and a concave portion surrounding the convex portions, and carries a one-component developer In a developing device comprising an agent carrier and a metal blade that regulates the amount of a one-component developer that contacts and adheres to the developer carrier,
A developing device, wherein a synthetic resin layer is formed only in a concave portion of the developer carrying member.   The developing device according to claim 1, wherein a charge control agent is added to the synthetic resin layer.   The developing device according to claim 1, wherein conductive fine particles are added to the synthetic resin layer.   4. The developing device according to claim 1, wherein a toner having an average particle size of 6 [mu] m or less is used.   5. The developing device according to claim 1, wherein the developer carrying member is disposed at a predetermined interval from the image carrying member.   When individual particles of toner are projected onto a flat surface, toner having an average circularity defined by the value of the circumference of the equivalent circle having the same projected area / the circumference of the individual particles is 0.95 or more. The developing device according to claim 1, wherein: At least an image carrier;
Charging means for charging the surface of the image carrier;
Latent image forming means for forming an electrostatic latent image on the image carrier;
An image forming apparatus having development 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 means.