JP2013195451A - Development device, image formation device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a development device that allows developer to be separated from a developer recovery member without giving a stress to the developer carried on a surface of the developer recovery member for recovering the developer from the developer carrier, and to provide an image formation device including the development device, and a process cartridge.SOLUTION: A development device 4 comprises: a development roller 42 a surface of which moves endlessly with toner T carried on the surface, and which supplies the toner T to a latent image on a surface of a photoreceptor 2 in a development area α facing the photoreceptor 2 and develops the latent image; a toner reception part 43 that receives the toner T inside; and a supply roller 44 that supplies the toner T in the toner reception part 43 to the surface of the development roller 42. The supply roller 44 functions as a recovery roller that recovers the toner T from the surface of the development roller 42 having passed the development area α, and includes an air pump 446 that generates an air flow to be discharged from the inside of an endless movement surface of the supply roller 44 toward the outside thereof.

Description

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

  Patent Document 1 discloses a regular pattern in which the height of a convex portion and the depth of a concave portion are constant on the surface of a developing roller that conveys toner to a developing region that is a portion facing a photosensitive member that is a latent image carrier. A developing device having irregularities made of is described. In this developing device, the toner existing on the convex portion is removed by the regulating member, so that the toner on the surface of the developing roller is only the toner contained in the concave portion, the concave portion has a constant depth, and the formation pattern is regular. Therefore, the toner carrying amount is substantially stabilized over the circumference of the developing roller. In such a developing device, a desired amount of toner can be transported to the developing region by setting the capacity of the recess to a capacity for carrying a desired amount of toner.

In a developing device using a developing roller having unevenness on the surface as described in Patent Document 1, after being accommodated in the recess of the developing roller, the toner that has passed through the developing region without being contributed to the development is not recovered. The following problems may occur.
That is, the toner accommodated in the concave portion is frictionally charged by rubbing by the restricting member when passing through the restricting position by the restricting member or by rubbing by another member, and is in a charged state necessary for development in the developing region. However, if the toner in the concave portion on the surface of the developing roller after passing through the developing area is not collected and is further frictionally charged by rubbing with the regulating member or another member while being accommodated in the concave portion, Compared to other toner newly accommodated in the recess, the toner becomes highly charged. When the ratio of such highly charged toner in the toner on the developing roller increases, the amount of toner that moves to the latent image decreases due to the potential difference between the surface of the developing roller and the latent image on the photoreceptor in the developing region, and development There is a possibility that developability may deteriorate due to accumulation of driving time of the apparatus.

  In Japanese Patent Application No. 2011-259439 (hereinafter referred to as the prior application), the applicant contacts a developing roller having a surface with irregularities, and the surface of the developing roller moves in the opposite direction to the developing roller. A developing device having a supply roller for supplying toner to the surface is proposed. In the developing device described in this prior application, toner is transferred from the supply roller to the developing roller on the upstream side in the surface movement direction of the supply roller in the supply nip where the supply roller contacts the developing roller (on the downstream side in the surface movement direction in the developing roller). Made. After being transferred from the supply roller to the development roller, the toner on the surface of the development roller that has not contributed to development in the development area and has passed through the development area is upstream of the surface of the development roller in the supply nip (in the supply roller) The toner is collected from the surface of the developing roller by the supply roller at a portion on the downstream side in the surface movement direction). As a result, the surface of the developing roller passes through the supply nip in a reset state, and the toner is again supplied from the supply roller on the downstream side of the surface of the developing roller in the movement direction of the developing roller. That is, in the developing device of the prior application, the supply roller has a role as a collection roller.

  In the configuration including the collecting roller for collecting the toner from the surface of the developing roller as described above, the toner is stored in the concave portion on the surface of the developing roller after passing through the developing region. Toner can be prevented from being generated.

However, when the toner collected by the collecting roller does not separate from the collecting roller and reaches the position where the collecting roller contacts the developing roller again and adheres to the developing roller, the toner remains in the recess. As in this case, a highly charged toner may be generated and developability may be reduced.
As a method of separating the toner moved from the developing roller to the collecting roller from the collecting roller, a scraper is brought into contact with the collecting roller and the toner on the collecting roller is peeled off as in the developing device described in Patent Document 2. A method is conceivable. However, with this method, when the toner is removed with a scraper, the toner is stressed, and the toner may be deteriorated.

  Such a problem is not limited to the configuration having regular irregularities on the surface of the developer carrying member such as a developing roller, and the developer is collected from the developer carrying member and the surface of the developer carrying member. A similar problem may occur if the developing device includes a developer collecting member that carries the developer on the surface and moves the surface endlessly.

  The present invention has been made in view of the above-described problems, and the object thereof is to give no stress to the developer carried on the surface of the developer collecting member for collecting the developer from the developer carrying member. It is another object of the present invention to provide a developing device that can be separated from the developer recovery member, and an image forming apparatus and a process cartridge including the developing device.

  In order to achieve the above object, the invention of claim 1 of the present application is that the developer is carried on the surface, the surface is moved endlessly, and the latent image on the surface of the latent image carrier is exposed in the development region facing the latent image carrier. A developer carrying member for supplying a developer to an image and developing the developer, a developer containing portion for containing the developer therein, and a developer for supplying the developer in the developer containing portion to the surface of the developer carrying member And a developer collecting member that collects the developer from the surface of the developer carrying member that has passed through the developing region, and carries the collected developer on the surface and moves endlessly. And a recovery member airflow generation means for generating an airflow discharged from the inside to the outside of the endlessly moving surface of the developer recovery member.

  According to the present invention, the recovery member airflow generation means generates an airflow that is discharged from the inside of the surface of the developer recovery member toward the outside, and the developer on the surface of the developer recovery member is blown by this airflow, There is an excellent effect that the developer carried on the surface of the developer collecting member can be separated from the developer collecting member without applying stress to the developer.

1 is a schematic configuration diagram of a developing device to which the present invention is applied. 1 is a schematic configuration diagram of a copier according to a first embodiment. FIG. 2 is a schematic configuration diagram of a developing device according to the first embodiment. FIG. 3 is a first perspective explanatory view of the developing device according to the first embodiment. FIG. 3 is a second perspective explanatory view of the developing device according to the first embodiment. FIG. 3 is an explanatory cross-sectional view of the developing device according to the first embodiment. FIG. 3 is a perspective view illustrating a part of the developing device according to the first embodiment in a cross-sectional view. FIG. 3 is an enlarged perspective view of the vicinity of one end of the developing device, with the lower case not shown. FIG. 9 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 8. FIG. 4 is an enlarged perspective view of the vicinity of the other end of the developing device, with the lower case not shown. FIG. 11 is an enlarged perspective view of the developing device from which the developing roller is omitted from the state of FIG. 10. FIG. The side view of a developing roller. Explanatory drawing of the surface shape of the developing roller, (a) is a schematic diagram of the entire developing roller, (b) is an enlarged view of a part of the surface of the developing roller, (c) is L11 or L13 in (b) Sectional drawing of the surface layer shown by (d), Sectional drawing of the surface layer shown by L12 or L14 in (b). The perspective explanatory view of a supply roller. The side view of a supply roller. The perspective explanatory drawing of a doctor blade. The side view of a doctor blade. FIG. 3 is an enlarged explanatory view of a doctor portion of a developing device in a state where a doctor blade is placed on the stomach. FIG. 3 is an enlarged explanatory view of a doctor unit of a developing device in a state where a doctor blade is in a tip contact state. FIG. Side view of paddle. Explanatory view of the contact state of the doctor blade with the developing roller, (a) is an explanatory view of the state where the blade is brought into contact with the tangential direction of the developing roller, (b) is a normal direction of the blade folder from the state of (a) Explanatory drawing of the state moved to (c), (c) is explanatory drawing of the state which moved the blade folder in the tangential direction from the state of (b). The graph which shows the experimental result of Experiment 1. The enlarged explanatory view of the state of edge contact. The graph which shows the experimental result of Experiment 2. The graph which compares the amount of cutting of the doctor blade by the difference in the material of Experiment 3. FIG. 4 is an explanatory diagram of a circulation path of toner collected from a developing roller. FIG. 3 is a schematic explanatory diagram of a developing device in which a scraper is brought into contact with a collection roller. Explanatory drawing of the supply roller with which the image development apparatus of a comparative example is provided, (a) is sectional drawing, (b) is a side view. FIG. 4 is an enlarged explanatory view of a supply roller included in the developing device according to the present invention, (a) is a cross-sectional view, and (b) is a side view. The graph which shows the experimental result of Experiment 4. The graph which shows the adhesive force relationship between the collection | recovery roller and toner with respect to a humidity change. Explanatory drawing of the supply roller with which the developing device of a modification is provided, (a) is sectional drawing, (b) is a side view. FIG. 4 is a schematic cross-sectional view of a main part of a printer according to a second embodiment. FIG. 3 is an enlarged sectional view of one of four process cartridges provided in the printer. FIG. 3 is an enlarged cross-sectional view in the vicinity of an end portion in the axial direction of the process cartridge. Sectional drawing along the axial direction of the image development apparatus with which the process cartridge is provided.

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

The printer unit 100 includes a process cartridge 1 (Y, M, C, K) as four process units, an intermediate transfer member that is stretched by a plurality of stretching rollers and moves in the direction of arrow A in FIG. A transfer belt 7, an exposure device 6 as an exposure unit, a fixing device 12 as a fixing unit, 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 omitted below. I will explain.

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

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

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

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

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

  With respect to the position where the four process cartridges 1 are opposed to the intermediate transfer belt 7, the intermediate transfer belt 7 is located on the downstream side in the surface movement direction with respect to the secondary transfer counter roller 9 a that is one of the stretching rollers. A secondary transfer roller 9 is disposed at a position opposed to the belt 7 and forms a secondary transfer nip 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 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 S in FIG. 2, passes through the secondary transfer nip. 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.

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

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

Next, the developing device 4 provided in the copying machine 500 will be described with reference to FIGS.
FIG. 3 is a schematic diagram showing a schematic configuration of the developing device 4, and is a cross-sectional view seen from the back side of the paper surface in FIG. 4 and 5 are perspective explanatory views of the developing device 4, and are perspective explanatory views of the developing device 4 as viewed obliquely from above in different directions.

  The developing casing 41 that forms the outer shape of the developing device 4 is formed by combining an upper case 411, an intermediate case 412, and a lower case 413. The middle case 412 forms a toner accommodating portion 43, and the upper case 411 is formed with a toner replenishing port 55 that is a developer replenishing portion that communicates the toner accommodating portion 43 with the outside. The upper case 411 is provided with an inlet seal 47 that seals a gap between the developing roller 42 and the upper case 411.

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

In the middle case 412, 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 are provided.
The developing device 4 is provided with an opening 56 that communicates the inside and the outside so as to extend along the longitudinal direction (Y-axis direction in the drawing). A cylindrical developing roller 42 is provided in the opening 56 to carry and carry the toner from the inside to the outside (developing area α facing the photoconductor).

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

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

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 photosensitive member 2, toner adheres to the electrostatic latent image portion on the surface of the photosensitive member 2, and development is performed. The photoreceptor 2 rotates in the direction of arrow D in FIG. 3 without contact with the developing roller 42. For this reason, in the development area α, the surface movement direction of the developing roller 42 and the surface movement direction of the photosensitive member 2 are the same direction.
The developing bias power supply 142 also 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 developing the latent image with the toner conveyed to the developing region α. A voltage applying unit that applies an alternating voltage having a second voltage for directing the toner to the developing roller 42.

As will be described in detail later, the surface of the developing roller 42 has a regular uneven shape having a substantially constant height of the convex portion 42a and a depth of the concave portion 42b over the entire outer peripheral surface.
The toner T on the surface of the developing roller 42 that 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 upstream side in the rotation direction of the developing roller 42 in the supply nip β, and developed. The surface of the roller 42 is reset. That is, the supply roller 44 also has a role as a collection roller.

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

In the developing device 4 of the first embodiment, the surface movement direction of the developing roller 42 and the surface movement direction of the supply roller 44 are opposite to each other in the supply nip β where the developing roller 42 and the supply roller 44 face each other. As a result, the linear velocity difference between the surface of the developing roller 42 and the surface of the supply roller 44 at the supply nip β increases, and the recovery performance of the supply roller 44 at the supply nip β can be improved. Therefore, it is possible to suppress the toner from being held on the developing roller 42, to suppress the toner from adhering to the surface of the developing roller 42, and the toner T (developing) on the surface of the developing roller 42 (developer carrier). It is possible to suppress the occurrence of density unevenness during development due to the fixing of the agent.
Further, in the developing device 4 of the first embodiment, the linear speed ratio between the developing roller 42 and the supply roller 44 is the surface moving speed of the developing roller 42: the surface moving speed of the supply roller 44 = 1: 0.85. However, the linear speed ratio is not limited to this value.

  Further, as shown in FIG. 3, in the developing device 4, the supply roller 44 is disposed above the toner storage portion 43, and at least a part of the supply roller 44 is in the toner storage portion 43 in a state where the rotation of the paddle 46 is stopped. The surface is higher than the agent surface Tf of the toner T. A region on the downstream side in the surface movement direction of the supply roller 44 with respect to the supply nip β (hereinafter referred to as a supply nip downstream region) is above the agent surface Tf of the toner T. When the toner is filled in the downstream area of the supply nip as in the configuration shown in FIG. 4 of Patent Document 1, the toner filled in the downstream area of the supply nip is replaced with new toner in the downstream area of the supply nip. This may hinder entry of toner and reduce the efficiency of collecting toner from the developing roller 42 in the supply nip β. On the other hand, as shown in FIG. 3, in the developing device 4 of the first embodiment, since the downstream area of the supply nip is above the surface of the toner T, the downstream area of the supply nip is not filled with toner. Therefore, the toner existing in the downstream area of the supply nip is not hindered from collecting the toner from the developing roller 42 in the supply nip β, so that the toner can be efficiently collected and the toner can be reset. It can be improved.

Next, the developing roller 42 will be described with reference to FIGS.
FIG. 12 is an explanatory perspective view of the developing roller 42, and FIG. 13 is a side view of the developing roller 42. 14 is an explanatory view of the surface shape of the developing roller 42, FIG. 14A is a schematic view of the entire developing roller 42, and FIG. 14B is shown in FIG. 14A. 3 is an enlarged view of a part of the surface of the developing roller 42. FIG. 14C is a cross-sectional view of the surface layer 42f (see FIG. 25) of the developing roller 42 at a cross section indicated by L11 or L13 in FIG. 14B, and FIG. 14D is a cross-sectional view of FIG. It is sectional drawing of the surface layer 42f of the developing roller 42 in the cross section shown by L12 or L14 in b).

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

As shown in FIG. 25, the developing roller 42 includes a base material 42g and a surface layer 42f formed on the outer peripheral surface of the base material 42g. The base 42g is made of a metal material sleeve such as an aluminum-based material such as 5056 aluminum alloy or 6063 aluminum alloy, or an iron-based material such as STKM.
The developing roller 42 performs uneven processing on the surface of the metal material sleeve which is the base material 42g, and nickel plating is applied to the metal material sleeve subjected to the uneven processing, so that the development roller 42 such as generation of rust occurs. A surface layer 42f for preventing corrosion and assisting charging of the toner is formed.

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

The first groove L1 and the second groove L2 are both periodically formed with a predetermined periodic width in the inclined direction, so that the convex portion 42a is formed with the pitch width W1 in the axial direction. In addition, the first groove L1 and the second groove L2 can have different inclination angles and periodic widths. Further, the axial length W2 of the top surface 42t of the convex portion 42a is formed to be not less than ½ of the pitch width W1.
In the developing roller 42 of Embodiment 1, the pitch width W1 in the axial direction of the convex portion 42a is 80 [μm], and the axial length W2 of the top surface 42t of the convex portion 42a is 40 [μm]. Furthermore, the recess depth W3, which is the height from the recess 42b to the top surface 42t of the protrusion 42a, is 10 [μm]. The values of the pitch width W1, the axial length W2 of the top surface 42t, and the recess depth W3 are merely examples, and are not limited to these values.

  As for the developing roller 42, it is desirable that the surface layer 42f is 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.

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

  Further, the height of the convex portion 42a (the concave portion depth W3) of the developing roller 42 is desirably larger than the weight average particle diameter of the toner T to be used. Since the toner T having an average size is accommodated in the recess 42b, the selection of the particle size is difficult to occur, and the M / A value (the amount of toner carried per unit area on the surface of the developing roller) is stabilized over time. .

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

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

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

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

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

Next, the doctor blade 45 will be described with reference to FIGS. 6, 17 and 18.
FIG. 17 is a perspective explanatory view of the doctor blade 45, and FIG. 18 is a side view of the doctor blade 45.
As shown in FIGS. 6 to 11, a doctor blade 45 is provided in the middle case 412 that is below the developing roller 42 and is inside the lower case 413.
The doctor blade 45 includes a blade member 450 that is a thin plate-shaped metal member that constitutes a regulating member, and a metal pedestal 452 (blade folder 45c in FIG. 3) to which one end of the blade member 450 is fixed. Have. The other end side of the blade member 450 is configured to come into contact with the developing roller 42.

Here, the contact state of the doctor blade 45 to the developing roller 42 will be described with reference to FIGS. 19 and 20.
FIG. 19 is an enlarged explanatory view of the doctor portion when the contact state of the doctor blade 45 with the developing roller 42 is a stomach contact state in which a surface portion closer to the root side than the tip of the doctor blade 45 is in contact. FIG. 20 is an enlarged explanatory view of the doctor portion when the contact state of the doctor blade 45 with the developing roller 42 is an edge contact state in which the tip of the doctor blade 45 contacts. As shown in FIG. 20, the doctor blade 45 is in contact with the developing roller 42 in a tip contact state (edge contact) state as shown in FIG. 20, and as shown in FIG. Any of the abdominal contact state may be sufficient.
However, in the tip contact state shown in FIG. 20, the toner T present on the top surface 42t of the convex portion 42a can be worn out, and only the toner T present in the concave portion 42b is conveyed to the development region α. This is preferable because the amount of toner conveyed to the development area α is stable. Further, by scraping off the toner T present on the top surface 42t of the convex portion 42a, a toner thin layer can be formed without applying pressure to the toner, and the durability of the toner can be improved. .

Here, the edge contact means that the edge portion 45e forming a ridge line between the opposing surface 45b of the doctor blade 45 and the tip surface 45a contacts the surface of the developing roller 42 (the top surface 42t which is the surface of the convex portion 42a). It is a state to do. Here, the edge part 45e shows the vicinity of the virtual straight line where two virtual planes obtained by extending the facing surface 45b of the doctor blade 45 and the tip surface 45a intersect each other. And as the edge part 45e which forms the ridgeline used as the virtual straight line vicinity, the ridgeline may be rounded or it may be chamfered. More specifically, a corner (edge 45e, which may be rounded or chamfered) on the developing roller 42 side at the free end of the flat doctor blade 45 may be convex. What is necessary is just to come in contact with the part 42a.
As for the edge contact direction, as shown in FIGS. 3 and 20, the portion where the doctor blade 45 is fixed rotates the developing roller 42 more than the portion where the doctor blade 45 is in contact with the developing roller 42. It is located downstream in the direction. That is, the free end is configured to abut against the rotation of the developing roller 42.

  As shown in FIGS. 20 and 25, when the edge portion hits the top surface 42t, the toner T is thinned so as to be worn by the doctor blade 45. Only the toner T buried in the toner is conveyed. For this reason, the amount of toner on the surface of the developing roller 42 can be set to a desired amount according to the volume of the recess 42b, and the amount of toner transported by the developing roller 42 can be stabilized. In addition, since a metal blade made of a metal leaf spring material has a certain degree of rigidity, the metal blade springs into the recess 42b of the developing roller 42 by its elasticity rather than that of a resin such as rubber, so that the inside of the recess 42b. The possibility of scraping off the toner is low, and the amount of toner transported by the developing roller 42 can be stabilized.

  As a configuration for bringing the doctor blade 45 into contact with the developing roller 42, there is a method in which the doctor blade 45 (blade member 450) is bent and brought into contact with the bent portion. Contacting the free end is more effective and more desirable.

  As shown in FIGS. 17 and 18, the blade member 450 of the doctor blade 45 is fixed to the base portion 452 by a plurality of rivets 451. The pedestal portion 452 is made of a metal that is thicker than the blade member 450 and functions as a substrate for fixing the blade member 450 to the main body of the developing device 4 (side surface portion of the middle case 412). A pin hole 454 is provided at the longitudinal end of the pedestal portion 452, one is a perfect circular main reference hole 454 a, and the other is an elliptical secondary reference hole having a long diameter in the direction of the main reference hole 454 a. 454b. When a pin (not shown) enters the main reference hole 454a, the position of the pedestal portion 452 with respect to the main body of the developing device 4 is determined and supported by the sub reference hole 454b. The pedestal portion 452 to which the blade member 450 is fixed is fixed to the developing device 4 main body (inner case 412) with a doctor fixing screw 455, whereby the blade member 450 is fixed to the developing device 4.

  As the blade member 450 of the doctor blade 45, a metal leaf spring material such as SUS304CSP, SUS301CSP, or phosphor bronze can be used. The blade member 450 abuts the free end side against the surface of the developing roller 42 with a pressing force of 10 to 100 [N / m], and regulates the toner passing under the pressing force to a predetermined amount and frictionally charges. The charge is given by. Further, a bias is applied to the blade member 450 from a doctor bias power source 145 to assist frictional charging.

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

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

Next, the paddle 46 will be described with reference to FIG. 6, FIG. 21, FIG.
FIG. 21 is a perspective explanatory view of the paddle 46, and FIG. 22 is a side view of the paddle 46.
A toner accommodating portion 43 is provided in the developing device 4 as a space for accommodating toner, and a paddle 46 is rotatably attached to the developing casing 41 in the toner accommodating portion 43.

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

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

In the paddle 46, the protruding amount of the paddle blade 460 is set to such a length that the tip of the paddle blade 460 extending from the paddle shaft 461 contacts the inner wall surface of the toner containing portion 43. As shown in FIGS. 3 and 6, the bottom surface portion 43 b of the toner accommodating portion 43 has an arc shape along the rotation direction of the paddle 46, and the paddle blade 460 is moved by the rubbing operation accompanying the rotation of the paddle 46. 43 is prevented from being caught by the bottom surface portion 43b.
A side wall surface portion 43 s that rises perpendicularly from the bottom surface portion 43 b is formed on the developing roller 42 side of the toner containing portion 43. A step portion 50 is formed horizontally in the direction toward the roller.

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

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

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

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

Next, the inlet seal 47 will be described with reference to FIGS.
A sheet member such as Mylar is attached as an inlet seal 47 along the longitudinal direction to the edge portion forming the opening 56 of the upper case 411. The inlet seal 47 is a substantially rectangular sheet, one end of which is affixed to the edge portion of the upper case 411, and the other end is a free end. The free end side of the inlet seal 47 protrudes toward the inside of the developing device 4, and is further provided so as to contact the developing roller 42. The inlet seal 47 is fixed to the upper case 411 on the upstream side in the 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 59 will be described with reference to FIGS.
As shown in FIGS. 8 to 11, side seals 59 are attached to a part of the middle case 412 corresponding to both ends in the longitudinal direction of the opening 56 of the developing device 4. The side seal 59 is provided on the inner side in the axial direction with respect to the spacer 422 provided in the vicinity of both ends in the axial direction of the developing roller 42, and in a region where the axial end where the doctor blade 45 contacts the developing roller 42 overlaps. ing. Such a side seal 59 prevents the toner from leaking from the end portion in the longitudinal direction of the opening 56 in the developing casing 41.
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 the toner in the developing device 4 will be described with reference to FIG.
The toner replenished into the developing device 4 from the toner replenishing port 55 is supplied to the toner accommodating portion 43 by the supply screw 48 and stirred by the paddle 46. Further, the paddle 46 is flipped up in the direction of the developing roller 42 and the supply roller 44 and conveyed. The toner supplied to the supply roller 44 is delivered to the surface of the developing roller 42 at a supply nip β where the supply roller 44 contacts the developing roller 42. Of the toner delivered to the surface of the developing roller 42, the amount of toner exceeding a predetermined amount conveyed to the developing area α is scraped off from the surface of the developing roller 42 by the doctor blade 45.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
The polycondensation reaction 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 fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.
The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. 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 the amine 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; phenol derivatives, oximes, polyisocyanates; Those 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.) and the like.

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

  Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of 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] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated. The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

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

  When reacting the polyvalent isocyanate compound (PIC) and when reacting (A) and (B), a solvent may be used as necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers Inactive to polyvalent isocyanate compounds (PIC) such as benzene (such as tetrahydrofuran).

  In addition, in the crosslinking and / or 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 Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% [%], preferably 3 to 10% [%] based on the toner.

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

<Charge control agent>
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. 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. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

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

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, 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, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

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

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage which exists on the surface of a toner base particle becomes the range of 10-90 [%]. 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 name is PB- 200H (manufactured by Kao Corporation), SGP (manufactured by Sokensha), technopolymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.) and the like.

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

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

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

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

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

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

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

  As shown in FIGS. 3, 19, and 20, in the developing device 4 of the first embodiment, the developing roller 42 whose rotational direction is the arrow B direction in the drawing moves downward from above in the doctor portion. In such a case, since the downward force (Fg) is applied to the toner by its own weight acting on the toner T, the compressive force on the toner due to the stress (Fb) of the doctor blade 45 can be reduced. Therefore, it is possible to suppress the toner from aggregating at a portion of the convex portion 42a of the developing roller 42 on the downstream side in the surface movement direction of the developing roller 42 (portion 42c in FIGS. 19 and 20). As a result, the occurrence of filming can be suppressed, and fluctuations in the Q / M value and M / A value on the developing roller 42 can be suppressed.

  Further, as the toner that is a developer used in the developing device 4, a toner having an acceleration aggregation degree of 40% or less is used, so that a portion of the convex portion 42 a of the developing roller 42 on the downstream side in the surface movement direction of the developing roller 42. It is possible to further alleviate the toner aggregation at (the portion 42c in FIGS. 19 and 20).

Next, advantages when the doctor blade 45 (blade member 450), which is a restriction member, is a metal blade will be described.
In the developing device described in Patent Document 1, a rubber member is used as a regulating member that comes into contact with the developing roller on which a certain regular uneven shape is formed. However, in the configuration using the rubber regulating member, the amount of toner on the developing roller may vary when the protruding amount of the regulating member changes due to assembly tolerance at the time of manufacture or scraping of the blade used over time. Specifically, the toner on the developing roller becomes extremely small, the image density becomes thin, or conversely, the toner amount on the developing roller increases, charging failure occurs, and the background portion of the image becomes Occasionally, dirty soiling may occur.
On the other hand, by using a metal blade as the doctor blade 45 of the developing device 4, the amount of toner on the developing roller 42 can be stabilized even if the protruding amount of the doctor blade 45 changes within a certain range. Can do.

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

First, the doctor blade 45 is brought into contact with the developing roller 42 in an edge-contacted state so that the doctor blade 45 extends in a tangential direction (vertical direction in FIG. 23) at the initial contact position Q1 with respect to the developing roller 42. . Here, the edge contact is a state in which an edge portion forming a ridge line between the facing surface 45 b and the tip surface 45 a of the doctor blade 45 is in contact with the surface of the developing roller 42.
Here, in the edge portion forming the ridge line, the ridge line may be rounded or chamfered. That is, the edge portion indicates the vicinity of a location where a surface obtained by extending the opposing surface 45b of the doctor blade 45 and the tip surface 45a intersects.
Specifically, a corner (which may be rounded or chamfered) of the developing roller 42 at the tip of the flat doctor blade 45 at the free end contacts the convex portion 42 a of the developing roller 42. It only has to come to do.
Here, as a method of bringing the doctor blade 45 into contact, there is a method in which a flat blade member is bent and the bent portion is brought into contact. However, as described above, the effect of scavenging the toner is the free end side of the blade member. The method in which the tips of the two are brought into contact is more effective and desirable.

  Next, the blade holder 45c (pedestal portion 452) that supports the root of the doctor blade 45 is moved along the normal direction of the developing roller 42 at the initial contact position Q1 (the direction indicated by the arrow X in FIG. 23A). Move to the side. As a result, as shown in FIG. 23 (b), the position of the doctor blade 45 that contacts the developing roller 42 moves to the base side, the doctor blade 45 bends, and the doctor blade 45 It becomes a contact state. The bumping is a state where the facing surface 45b of the doctor blade 45 facing the developing roller 42 is in contact with the edge portion and not in contact with the edge portion. Further, the contact position Q of the doctor blade 45 on the surface of the developing roller 42 at this time is displaced upward in FIG. 23 from the initial contact position Q1.

  In the state shown in FIG. 23B, the blade folder 45c is moved away from the developing roller 42 along the direction (vertical direction in FIG. 23) perpendicular to the normal direction at the initial contact position Q1 (the arrow in FIG. 23). When it is moved in the Z direction), the amount of protrusion gradually decreases. And as shown in FIG.23 (c), it will be in the state of edge contact in the state in which the doctor blade 45 has bent. When the blade folder 45c is moved in the Z direction so that the protruding amount is further decreased from the state shown in FIG. 23C, the amount of deflection of the doctor blade 45 is increased until the doctor blade 45 is separated from the developing roller 42. The edge contact state is maintained while decreasing.

  When the doctor blade 45 is a metal blade made of metal (phosphor bronze) and when it is a rubber blade made of urethane rubber, the protrusion amount is changed by the method of changing the protrusion amount described with reference to FIG. FIG. 24 shows the experimental results of measuring the change in the toner conveyance amount on the developing roller 42 at that time.

In the graph shown in FIG. 24, the position of the doctor blade 45 in the state shown in FIG. The displacement when the blade folder 45c is moved in the arrow Z direction in FIG. 23 from the zero position is-(minus), and when the blade folder 45c is moved in the direction opposite to the arrow Z direction in FIG. The displacement is shown as + (plus). In other words, the right side of the drawing in FIG.
The graph shown by the broken line in FIG. 24 is the experimental result when the rubber blade is used, and the graph shown by the solid line is the experimental result when the metal blade is used.

As shown in FIG. 24, when the position of the doctor blade 45 is in the + (plus) direction, the toner conveyance amount increases as the positions of both the metal blade and the rubber blade increase to plus.
On the other hand, when the position of the doctor blade 45 is in the − (minus) direction, a metal blade (solid line) has a region showing a stable conveyance amount as shown in FIG. On the other hand, in the case of the rubber blade used in the conventional developing device (broken line), the toner was hardly conveyed onto the developing roller 42 at the position in the − (minus) direction.

According to the experiment described with reference to FIG. 24, regarding the amount of protrusion with respect to the developing roller 42 having a regular uneven shape on the surface, the metal doctor blade 45 has a desired amount of toner on the developing roller 42 rather than rubber. It was found that the range of the protruding amount is wide.
Therefore, by using a metal blade as the doctor blade 45 as in the present invention, the margin of design tolerance in the Z direction in FIG. 23 when the doctor blade 45 is attached is increased, and the assemblability is improved. Furthermore, the margin of mechanical tolerances is increased, and the cost of parts can be reduced.

FIG. 25 is an enlarged explanatory view of a contact position Q (see FIG. 23) between the doctor blade 45 and the developing roller 42 in the edge contact state.
As described with reference to FIG. 24, when the metal blade is used as the doctor blade 45, the region where the toner amount is stable is obtained because the edge portion 45e at the tip of the doctor blade 45 contacts the developing roller 42. It is to do. Specifically, as shown in FIG. 25, when the edge 45e hits, the toner T is thinned so as to be worn by the doctor blade 45, so that the regular concave and convex portions 42b of the developing roller 42 are formed. Only the buried toner T is conveyed. For this reason, the amount of toner on the surface of the developing roller 42 can be set to a desired amount according to the volume of the recess 42b, and the amount of toner transported by the developing roller 42 can be stabilized. In addition, since a metal blade has a certain degree of rigidity, its elasticity can bite into the recess 42b of the developing roller 42 and scrape the toner in the recess 42b more than that of a resin such as rubber. The amount of toner conveyed by the developing roller 42 can be stabilized.

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

FIG. 26 is a graph showing the experimental results of Experiment 2.
In the graph of FIG. 26, when the doctor blade 45 is in the tangential direction of the surface of the developing roller 42 at the contact position Q, the blade folder from FIG. 29A to FIG. The horizontal axis represents the value of the movement distance X1 of 45c. In the graph of FIG. 26, the blade folder 45c is moved in the arrow Z direction in the figure from the state shown in FIG. 29B, and the vertical axis is zero when the state shown in FIG. 29C is reached. Then, the blade folder 45c is further moved in the arrow Z direction in the drawing from the state shown in FIG. 29C, and the movement distance of the blade folder 45c in the Z direction in the drawing until the doctor blade 45 is separated from the surface of the developing roller 42. Is the vertical axis.

  From the graph shown in FIG. 26, when the moving distance X1 is zero or more, the doctor blade 45 can maintain the edge contact as the moving distance X1 in the normal direction of the surface of the developing roller 42 at the initial contact position Q1 increases. The range can be expanded. When the movement distance X1 is equal to or greater than zero, the doctor blade 45 is disposed so as to be bent by contact with the developing roller 42. By arranging in this way, when the doctor blade 45 is attached, the margin of the vertical design tolerance in FIG. 23 is increased, so that the assembling property is improved. Furthermore, the margin of mechanical tolerances is increased, and the cost of parts can be reduced.

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

In Experiment 3, the doctor blades 45 made of the respective materials are arranged in the state shown in FIG. 23C, and a solid image is formed using the copying machine 500 of the first embodiment to check for the occurrence of streak images. confirmed. As a result of Experiment 3, no streak image was generated when phosphor bronze was used as the material of the metal blade, and a streak image was generated when SUS was used.
Here, the doctor blade 45 used in Experiment 3 was confirmed. As a result, the toner was fixed to the SUS doctor blade 45 in which the streak image was generated, and the doctor blade made of phosphor bronze in which the streak image was not generated. In 45, toner adhesion was hardly confirmed.

FIG. 27 is a graph showing the results of measuring the amount of scraping of the doctor blade 45 with respect to the rotation time of the developing roller 42 for the doctor blade 45 of each material used in Experiment 3. A graph indicated by a broken line in FIG. 27 shows a scraping amount when a SUS blade is used, and a graph indicated by a solid line is a scraping amount when a phosphor bronze blade is used.
FIG. 27 shows that phosphor bronze is easier to cut than SUS.
When the doctor blade 45 made of phosphor bronze is used, even if the toner is slightly fixed, the toner fixed together with the doctor blade 45 is scraped by sliding with the developing roller 42 before the toner fixing grows. Therefore, it is considered that the sticking does not grow and the streak that causes a problem in the image does not occur.

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

As described in Experiment 3, as a configuration for preventing the generation of a streak image in the developing device 4 according to the first embodiment, the toner in the lightly fixed state is scraped off together with the doctor blade 45 by rubbing against the developing roller 42. Therefore, it is necessary to cut the entire area of the doctor blade 45 in the width direction.
The developing roller 42 according to the first exemplary embodiment develops at any position in the width direction (direction perpendicular to the surface movement direction) on the surface of the groove forming portion 420a that is a surface carrying the toner to be supplied to the photoreceptor 2. At least one top surface 42t, which is the uppermost surface in the height direction of the convex portion 42a, exists in one round of the surface movement direction of the roller 42.

  As a configuration satisfying such a condition, the uneven shape on the surface at a position where the developing roller 42 is located (the position of L11, etc.) is such that convex portions 42a and concave portions 42b are arranged in a periodic row in the width direction. The concavo-convex shape at a position adjacent to the position in the surface movement direction (the position of L12, etc.) is an arrangement in which the regular row arrangement is shifted by a half cycle (see FIG. 13). In other words, the rows L12 and L14 adjacent to the row L11 and the row L13 in the rotation direction have a shape in which the period of the unevenness in the width direction is shifted by a half cycle. Further, the axial length W2 of the top surface 42t is formed to be not less than ½ of the pitch width W1. The surface shape is such that such a shape is repeated in the rotation direction of the developing roller 42.

  With such a configuration, in the doctor blade 45, when the position of L11 of the developing roller 42 is in contact with the position of the top surface 42t, the top surface 42t is in contact with the position of L12. With such a configuration, it is possible to realize a configuration in which the top surface 42t of the developing roller 42 is brought into contact once over the entire region in the width direction of the doctor blade 45 while the developing roller 42 makes one round. As described above, regardless of the position of the doctor blade 45 in the width direction, the top surface 42t is in contact with the developing roller 42 while making a round, and the doctor blade 45 can be efficiently scraped to fix the toner. It is possible to more reliably prevent the generation of a streak image due to.

In the configuration in which development is performed by bringing the surface of the developing roller 42 into contact with the photosensitive member 2, both the developing roller 42 and the photosensitive member 2 are not elastic. Therefore, due to an accuracy error at the time of manufacturing or assembly, the photosensitive member 2 and the developing member are developed. A portion where the roller 42 does not contact is generated. In this case, since the toner T does not move to the photosensitive member 2 only in a portion where the photosensitive member 2 and the developing roller 42 are not in contact with each other, the image is not developed.
On the other hand, in the developing device 4 of the first embodiment, the developing roller 42 is disposed so as to form a gap with respect to the photoreceptor 2, and a voltage obtained by superimposing an AC bias on the developing roller 42 by a developing bias power source 142. Is applied. Thus, the latent image can be developed by jumping the toner T from the developing roller 42 to the photosensitive member 2, and image loss can be prevented regardless of the accuracy of the position of the developing roller 42 with respect to the photosensitive member 2. Can do.

Next, problems of the conventional developing device will be described.
In an image forming apparatus such as a copying machine or a printer, various developing devices are used to develop an electrostatic latent image formed on a latent image carrier. As such a developing device, in addition to a two-component developing type developing device using a two-component developer containing toner and carrier, a one-component developing type using only toner as a developer without using a carrier. A developing device is known.
Further, in such a one-component developing type developing apparatus, a contact type developing is performed by bringing the developer held on the surface of the developer carrying body into contact with the surface of the image carrying body on which the electrostatic latent image is formed. In addition to the developing device, a developer carrying member is provided so as to face the image carrying member with a predetermined interval, and an alternating voltage is applied to the developer carrying member so that the developer carrying member and the image carrying member There is known a non-contact type developing device in which an alternating electric field is applied between the developer and the developer held on the surface of the developer carrier is supplied to the image carrier on which the electrostatic latent image is formed for development. It has been.

As a developer carrying member used in a one-component developing type developing device, generally, a roller having an elastic layer formed of rubber or the like, or a roller having a metal surface blasted to be roughened is used. It is done. However, when such a roller is used, the pressure between the developer carrying member and the toner layer regulating member is directly applied to the toner, so that the toner is likely to deteriorate, and the developability is deteriorated early. Further, there is a problem that the deteriorated toner is fixed to the toner layer regulating means, and noise is generated in the image.
With respect to such a problem, the developing device 4 according to the present embodiment has a developing roller 42 in which a plurality of convex portions 42a and concave portions 42b surrounding the convex portions 42a are periodically formed on the surface as a developer carrier. It has. By using such a developing roller 42, according to this, it becomes possible to form a toner thin layer while suppressing the pressure on the toner of the doctor blade 45 which is a toner layer regulating means, and the durability of the toner Can be improved.

  However, when such a developing roller is used, depending on the combination of the uneven shape of the developing roller and the characteristics of the supply roller, there is a possibility that the highly charged toner present in the concave portion of the developing roller may not be sufficiently collected. In this case, the toner that is not collected is triboelectrically charged again at the doctor portion and the supply nip β, thereby further increasing the charge. When such highly charged toner is generated, the electric mirror image force between the developing roller and the toner increases, and the adhesion force between the developing roller and the developing roller increases. Further, even when the pressure on the toner on the developing roller can be reduced, the toner held on the developing roller is deteriorated by repeated pressurization, so that filming on the developing roller and adhesion to the doctor blade are prevented. Cause. For this reason, there is a possibility that developability deteriorates due to accumulation of driving time of the developing device.

With respect to such a problem, in the developing device 4 of the present embodiment, the supply roller 44 has a role as a collection roller. As a result, it is possible to prevent the generation of highly charged toner due to the toner remaining in the recess 42b on the surface of the developing roller 42 after passing through the developing region α.
However, even if the toner on the developing roller is collected by the collecting roller, if the toner is not separated from the collecting roller and is immediately supplied again to the developing roller, the same toner is also applied to the doctor portion. Repeatedly passing, it causes generation of highly charged toner, filming on the developing roller, and sticking to the doctor blade.
For the problem caused by the toner not separating from the collecting roller, it is important to improve the collecting efficiency of the toner on the surface of the collecting roller and to circulate the toner in the developing device.

FIG. 28 is an explanatory diagram of the circulation path of the toner collected from the developing roller 42 in the developing device 4 as shown in FIG. 3, and the solid line arrow schematically shows the toner circulation path.
The developing device 4 shown in FIG. 28 and the like has a configuration in which supply and collection of toner are combined with a supply roller 44 that is a single roller. However, in the following description, development for supplying toner to the development roller is described. The same applies to a developing device in which the agent supply means and the collecting member for collecting toner from the developing roller are separate members.

In the figure, the toner collected from the developing roller 42 falls in the direction of gravity along with the rotation of the supply roller 44 that functions as the collection roller, or is peeled off by the centrifugal force of the supply roller 44 and is mixed with the toner in the toner accommodating portion 43. A path indicated by an arrow E and a path indicated by an arrow G in the figure supplied to the developing roller 42 without being peeled off from the supply roller 44 are conceivable.
In order to prevent the problems such as toner filming and sticking as described above, the toner collected on the developing roller 42 is reduced by reducing the amount of toner that follows the path indicated by the arrow B in FIG. It is desirable to increase the amount of toner that follows the path indicated by the arrow G in FIG.

As a method for peeling the toner from the collecting roller so as to follow the path indicated by the arrow G in the figure, a method using gravity or centrifugal force, a method using a scraper, a method using an electric field, or the like is already known.
However, the conventional collecting mechanism has a problem that it is difficult to control the position, direction, and strength of the toner from the collecting roller.
For example, when gravity is used, the direction of peeling is limited downward (the direction of gravity), and the strength of peeling is limited to the gravity strength. In addition, when using a centrifugal force, it is difficult to control at which position it is peeled off, and the strength depends on the rotational speed and the roller diameter. Usually, since the rotation speed of the collection roller is set in accordance with the speed at which the collection efficiency from the developing roller is good, it coincides with the good speed of peeling and does not always satisfy both.

  In addition, when the toner deteriorates or the environment fluctuates, the adhesion between the toner and the collecting roller increases, which may make it more difficult to peel off. However, in the configuration in which the toner is peeled off from the collecting roller using gravity or centrifugal force, the peeling strength cannot be changed in accordance with the change in adhesion force.

  Further, as a method of peeling off the toner from the collection roller (the supply roller 44 that also functions as the collection roller in the present embodiment), a method using a scraper 52 can be cited as shown in FIG. In the peeling method using the scraper, it is possible to design and control the peeling position by the arrangement of the scraper. However, since the scraper is brought into contact with the collecting roller and peeled off, the toner is stressed. Also, the peel strength is constant and cannot be changed.

  Further, as another peeling method, there is a method using an electric field. In this case, the peeling direction and strength can be controlled by the application method of the electric field. However, when an electric field is used, there is a problem that only properly charged toner is peeled off, and weakly charged and reversely charged toner cannot be peeled off from the collecting roller.

Next, features of the present invention will be described.
FIG. 1 is a schematic configuration diagram of a developing device 4 schematically showing a configuration of a characteristic portion of the present invention.
The developing device 4 shown in FIG. 1 includes an air pump 446 as a recovery member airflow generation unit that generates an airflow discharged from the inside to the outside of the surface of the supply roller 44 that functions as a recovery roller.
The solid arrows in FIG. 1 indicate the flow of toner, and the broken arrows indicate the flow of air that is an air flow generated by the air pump 446.

  The supply roller 44 provided in the developing device 4 has a configuration in which a supply roller cylindrical portion 440 made of an elastically deformable porous body is provided on the outer peripheral surface of the supply roller shaft 441 made of a material having high rigidity such as metal. The developing device 4 to which the present invention is applied has a configuration in which air flows from the center of the supply roller shaft 441 of the supply roller 44 through the supply roller cylindrical portion 440 toward the direction in which the toner is to be peeled off. ing.

FIG. 31 is an enlarged explanatory view of the supply roller 44 provided in the developing device 4 shown in FIG. FIG. 31A is a cross-sectional view of the supply roller 44 with respect to a cross section orthogonal to the axial direction of the supply roller 44, and FIG. 31B is a side view of the supply roller 44.
As shown in FIG. 31, the supply roller shaft 441 of the supply roller 44 has a double-cylindrical shape composed of two concentric cylindrical members of an inner cylindrical member 441a and an outer cylindrical member 441b. The inner cylindrical member 441a is fixed to the main body of the developing device 4, and the outer cylindrical member 441b smoothly rotates around the inner cylindrical member 441a (for example, by a bearing) when a rotational drive is input from a driving unit (not shown). Rotate to. A supply roller cylindrical portion 440 that is a developer contact layer that scrapes and collects toner from the developing roller 42 is fixed to the outer peripheral surface of the outer cylindrical member 441b, and rotates with the outer cylindrical member 441b relative to the inner cylindrical member 441a. .
In the developing device 4 shown in FIG. 31, the supply roller cylindrical portion 440 made of a porous sponge is used as the developer contact layer, but a brush roller-like recovery roller is used as the developer contact layer using a bristle brush. You may do it.

In the fixed inner cylindrical member 441a, an inner hole 443a is opened over the entire region in the axial direction at a position where it is desired to peel off a part of the cylindrical circumferential toner. On the other hand, the outer cylindrical member 441b has an outer hole 443b that extends over the entire area in the cylindrical circumferential direction and axial direction.
One end of the inner cylindrical member 441a in the axial direction is connected to an air pump 446 through an air transfer pipe 445. When the air pump 446 is driven and air flows from one axial end of the inner cylindrical member 441a as indicated by an arrow K in FIG. 31, as indicated by a broken arrow in FIGS. The air flows from the inner hole 443a of the inner cylindrical member 441a toward the radially outer side of the supply roller 44, and the air passing through the outer hole 443b of the outer cylindrical member 441b is provided on the outer periphery of the outer cylindrical member 441b. It is discharged from the inside of the supply roller cylindrical portion 440 toward the outside. Thereby, the toner adhering to the surface of the supply roller cylindrical portion 440 can be peeled off.

  Even in the case of using a brush roller as the collection roller, the air that has passed through the outer hole 443b of the outer cylindrical member 441b to which the bristle brush is fixed is transferred to the outer periphery of the outer cylindrical member 441b. By discharging from the base side toward the tip side, the toner adhering to the bristle brush can be peeled off.

The air pump 446 that generates the air flow may be of any type as long as the flow rate necessary for peeling can be secured.
In this embodiment, the air pump 446 that can be set in the range of 1 to 10 [L / min] is used as the air flow rate. However, the shape of the developing casing 41, the type of toner, and the required peeling efficiency. This value is not limited to this value because it varies depending on the value.
The timing for driving the air pump 446 and supplying the air is controlled so as to start with the rotation of the supply roller 44 and to stop the supply of air with the rotation of the supply roller 44 stopped.

  In the developing device 4, in order to flow air from the outside to the inside of the developing casing 41, it is necessary to provide an air escape path (passage path) for escaping the air coming from the supply roller 44 to the outside of the developing casing 41. In the developing device 4 of the present embodiment, as shown in FIG. 1, an opening in which a filter member 51 is disposed is provided above the toner containing portion 43 for the purpose of releasing air. The filter member 51 may be any material that does not allow toner to pass therethrough and allows air to pass therethrough. In this embodiment, the filter member 51 is a sponge having a cell count of 50 [pieces / 25 mm] and a thickness of 10 [mm].

  In the developing device 4 to which the present invention is applied, the toner attached to the supply roller 44 can be peeled off by the flow of air from the inside to the outside of the shaft of the supply roller 44 that functions as a collection roller. Since the scraper or the like is not brought into contact with the toner, the stress applied to the toner is very small and can be peeled off in any direction with almost no stress on the toner.

Further, the developing device 4 of the present embodiment has a configuration in which the control unit 700 can control the strength of the airflow generated by the air pump 446 (air flow rate).
By controlling the strength of the airflow, the strength to peel off the toner can be set arbitrarily, so that even if the toner and the recovery roller (supply roller 44) increase in adhesion due to toner deterioration or environmental fluctuations, the air The peeling efficiency can be maintained by increasing the flow rate. Regarding toner deterioration and environmental changes, the change is detected by another means such as a thermometer and humidity meter (not shown), and the control unit 700 controls the output of the air pump 446 based on the detection result, so that the toner pulling is performed. The strength of peeling can be adjusted, and the efficiency of peeling can be made constant.

Further, if the output of the low image area ratio with low toner consumption continues, the replacement of the toner is reduced, and the same toner continues to be stressed, and the adhesion between the toner and the collecting roller may increase. On the other hand, the control unit 700 detects the output image area ratio based on the image information used in the exposure apparatus 6 and increases the air flow rate of the air pump 446, whereby the toner peeling strength can be increased, and the peeling is performed. Efficiency can be maintained.
Further, when the total number of output sheets increases, the deterioration of the toner progresses, and the adhesion force between the toner and the collecting roller may increase. On the other hand, the control unit 700 detects the total number of output sheets and increases the air flow rate of the air pump 446, whereby the toner peeling strength can be increased and the peeling efficiency can be maintained.
In addition, since the peeling method uses air, the peeling efficiency is less affected by the charged state of the toner and the like than the peeling method using the electric field described above.

  As described above, in the developing device 4 shown in FIG. 1, the position of the toner peeling from the collection roller (supply roller 44) can be designed and controlled by setting the position of the inner hole 443a of the inner cylindrical member 441a. Further, by controlling the output of the air pump 446, it is possible to adjust the strength of the toner peeling from the collection roller (supply roller 44). Further, since the peeling is performed by air, the toner stress (charge or the like) is hardly affected, and the toner stress at the time of peeling can be reduced.

[Experiment 4]
Next, Experiment 4 in which the stress applied to the toner due to the difference in the peeling method from the collection roller (supply roller 44) is compared will be described.
FIG. 29 described above is a schematic configuration of the developing device 4 of the comparative example in Experiment 4, and FIG. 30 is an enlarged explanatory view of the supply roller 44 provided in the developing device 4 of the comparative example. 30A is a cross-sectional view of the supply roller 44 with respect to a cross section orthogonal to the axial direction of the supply roller 44, and FIG. 30B is a side view of the supply roller 44. As shown in FIG. 30, the supply roller 44 of the comparative example has a shape in which a supply roller cylindrical portion 440 is provided on a rod-like supply roller shaft 441.

In Experiment 4, a supply / collection roller (supply roller 44) is used in a configuration in which toner is peeled off by air as in the developing device 4 in FIG. 1 and in a configuration in which toner is removed by a scraper 52 such as the developing device 4 in FIG. ) And the paddle 46, which is a stirring member, was rotated for a predetermined time (0 to 90 [minutes]), and then the toner adhesion amount on the photoreceptor 2 when black solid was developed under a certain developing bias condition was compared.
In Experiment 4, in the configuration of the developing device 4 shown in FIG. 1, the air flow rate was fixed at 2 [L / min]. In the configuration of the developing device 4 shown in FIG. 29, a phosphor bronze blade having a thickness of 120 [μm] is used as the scraper 52 so as to have a biting amount of 1 [mm] with respect to the supply roller 44.

FIG. 32 is a graph showing the experimental results of Experiment 4.
In FIG. 32, the horizontal axis is the idling time, and the vertical axis is the toner adhesion amount on the photoreceptor 2. Also, the graph shown by the solid line in FIG. 32 shows the experimental result by the developing device 4 shown in FIG. 1 to which the present invention is applied, and the graph shown by the broken line in FIG. 32 shows the experimental result by the developing device 4 shown in FIG. .
As shown in FIG. 32, it can be understood that the toner adhesion amount on the photosensitive member 2 greatly decreases with time in the peeling with the scraper 52. This indicates that the toner deteriorates due to stress by the scraper 52, and the adhesion to the developing roller 42 is increased, making it difficult to develop.

In the peeling with air, the toner adhesion amount on the photosensitive member 2 hardly decreased with time. Accordingly, it can be determined that the toner can be peeled off in any direction with almost no stress on the toner by the configuration of the peeling using air as in the developing device 4 to which the present invention is applied.
In the developing device 4 used in this experiment, since the stress on the toner is suppressed, the developing device 4 shown in FIG. 1 has a unit life of 10 [10] compared to the developing device 4 shown in FIG. It is expected to grow to about [1,000 sheets] to 13 [1000 sheets].

As described above, a configuration in which the air flow rate is adjusted according to the toner usage environment and usage history is also conceivable. An example is flow rate control when the humidity environment changes.
FIG. 33 is a graph showing the adhesive force relationship between the collection roller (supply roller 44) and the toner with respect to humidity change.
Therefore, for example, when the relative humidity is 20 [% RH], the air flow rate is set to 3 [L / min], and when the relative humidity increases to 60 [% RH], the air flow rate is set to 4 [ L / min], the toner removal efficiency from the collecting roller can be maintained even when the humidity changes. For this reason, it is possible to prevent the toner peeling efficiency from being reduced due to humidity fluctuations and the deterioration of the toner to be accelerated.

[Modification]
Next, a modification of the developing device 4 to which the present invention is applied will be described.
FIG. 34 is an enlarged explanatory view of the supply roller 44 functioning as a collection roller provided in the developing device 4 according to the modification. 34A is a cross-sectional view of the supply roller 44 with respect to a cross section orthogonal to the axial direction of the supply roller 44, and FIG. 34B is a side view of the supply roller 44.

As shown in FIG. 34, the supply roller 44 of the modified example is different from the supply roller 44 of the above-described embodiment in that the supply roller shaft 441 does not have a double cylindrical shape, but a single cylindrical member (the outer side in FIG. 1). The cylindrical member 441b only).
The modified supply roller 44 does not include a fixed position opening (the inner hole 443a in FIGS. 1 and 31) that determines the position of the toner to be peeled off from the supply roller 44, and the entire area in the circumferential direction. A cylindrical supply roller shaft 441 in which a hole 443 that is an opening is formed rotates. For this reason, as shown in FIG. 34, there is a drawback that the direction in which the toner is peeled off cannot be controlled. However, in the case where the direction in which the toner is peeled off need not be controlled, the configuration shown in FIGS. Since the structure of the supply roller shaft 441 is simpler than the configuration and the cost can be reduced, it can be an option.

[Embodiment 2]
Hereinafter, a second embodiment (hereinafter referred to as a second embodiment) of the present invention in which the present invention is applied to a printer (hereinafter referred to as a printer 600) as an image forming apparatus will be described.
FIG. 35 is a schematic cross-sectional view of a main part of the printer 600 of the second embodiment. As shown in FIG. 35, the printer 600 includes a process cartridge 1 as four process units, an intermediate transfer belt 7 as an intermediate transfer member that is stretched by a plurality of stretching rollers and moves in the direction of arrow A in FIG. , An exposure device 6 as an exposure unit, a fixing device 12 as a fixing unit, and the like.

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

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

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

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

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

  In FIG. 35, a primary transfer roller 8 serving as a primary transfer unit is disposed at a position facing each photoconductor 2 with the intermediate transfer belt 7 interposed therebetween. The primary transfer roller 8 is provided with a high voltage power supply (not shown). A primary transfer bias is applied to form a primary transfer electric field with the photoreceptor 2. By forming a primary transfer electric field between the photosensitive member 2 and the primary transfer roller 8, the toner image formed on the surface of the photosensitive member 2 is transferred to the surface of the intermediate transfer belt 7. One of a plurality of stretching rollers that stretch the intermediate transfer belt 7 is rotated by a drive motor (not shown), so that the intermediate transfer belt 7 moves in the direction of arrow A in the figure. A full color image is formed on the surface of the intermediate transfer belt 7 by sequentially transferring the toner images of the respective colors on the surface of the intermediate transfer belt 7 moving on the surface.

  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 of the surface movement direction with respect to the secondary transfer counter roller 9a which is one of the stretching rollers. A secondary transfer roller 9 is disposed at a position opposed to the belt 7 and forms a secondary transfer nip with the intermediate transfer belt 7. Transfer paper which is a transfer material conveyed in the direction of arrow S in FIG. 35 by applying a predetermined voltage between the secondary transfer roller 9 and the secondary transfer counter roller 9a to form a secondary transfer electric field. When P passes through the secondary transfer nip, the full-color image formed on the surface of the intermediate transfer belt 7 is transferred onto the transfer paper P.

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

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

  Next, the developing device 4 provided in the process cartridge 1 will be described with reference to FIGS. 36 and 37 are enlarged cross-sectional views of one of the four process cartridges 1. FIG. 36 is a cross-sectional view in the vicinity of the central portion in the axial direction of the developing roller 42. FIG. It is sectional drawing in the position where the side seal 59 of this is arrange | positioned. FIG. 38 is a cross-sectional explanatory view in the vicinity of the rotation shafts of the toner conveying member 106, the toner agitating member 108, and the supply roller 44 that convey the toner T and are arranged substantially linearly in the vertical direction in the developing device 4. .

  The developing device 4 includes a toner storage chamber 101 that stores toner T, which is a developer, and a toner supply chamber 102 provided below the toner storage chamber 101. The toner storage chamber 101 and the toner supply chamber 102 are separated from each other. A partition member 110 is provided so as to partition. As shown in FIG. 38, the partition member 110 is provided with a plurality of openings. As a plurality of openings of the partition member 110, a supply port 111 that supplies the toner T in the toner storage chamber 101 to the toner supply chamber 102 and a return port 107 that returns the toner T in the toner supply chamber 102 to the toner storage chamber 101. And are provided.

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

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

  A toner conveying member 106 that conveys the toner T in the toner accommodating chamber 101 in a direction parallel to the rotation axis of the photoreceptor 2 (a direction perpendicular to the paper surface in FIG. 36) is provided in the toner accommodating chamber 101.

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

  As shown in FIG. 38, the toner conveying member 106 provided in the toner storage chamber 101 is a member having a rotating shaft in which a conveying screw shape portion 106a and a conveying plate shape portion 106b are combined. The toner conveying member 106 is configured to convey the toner T in the toner storage chamber 101 in a substantially horizontal direction (in the direction of arrow H in FIG. 38) parallel to the rotation axis of the toner conveying member 106 by the rotation operation of the conveying screw shape portion 106a. It has become. The developing device 4 includes a conveyance screw shape portion 106a that conveys the toner T in a direction parallel to the rotation axis of the toner conveyance member 106, but the developer conveyance member is not limited to this, and the conveyance device is not limited thereto. What has conveyance functions, such as a belt and a coiled rotating body, can be used. Furthermore, what has these conveyance functions and what has a loosening function, such as a paddle formed by bending a plate member such as a blade or a wire, may be combined.

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

  A toner stirring member 108 is disposed in the toner supply chamber 102 vertically below the partition member 110. As shown in FIG. 38, the toner stirring member 108 is a member having a rotating shaft in which a stirring screw shape portion 108a and a stirring plate shape portion 108b are combined. The toner agitating member 108 conveys the toner T in the toner supply chamber 102 in a substantially horizontal direction (arrow I or J direction in FIG. 38) parallel to the rotation axis of the toner agitating member 108 by the rotation operation of the agitating screw shape portion 108a. It can be configured.

  As shown in FIG. 38, the stirring screw-shaped portion 108a of the toner stirring member 108 spirals so as to convey the toner T in the direction toward the outside (the direction of arrow I in FIG. 38) across the supply port 111 in the axial direction. Shaped wings are provided. Further, the stirring screw-shaped portion 108a of the toner stirring member 108 has spiral wings on the outside and inside of the two return ports 107 in the axial direction. For this reason, the toner T supplied from the supply port 111 to the toner supply chamber 102 is conveyed outward in the axial direction (in the direction of arrow I) by the rotation of the stirring screw-shaped portion 108 a of the toner stirring member 108, and outside the return port 107. The reached toner T is conveyed toward the return port 107 (in the direction of arrow J) by the stirring screw-shaped portion 108a whose wing portion is reversely wound. The transport direction of the toner T by the stirring screw-shaped portion 108 a is opposite between the outer side and the inner side in the axial direction across the return port 107, and a transfer force is applied to the toner T toward the return port 107. Below 107, the toner T is collected from both sides in the axial direction and pushed up in a mountain shape. As a result, when the amount of toner T supplied from the toner storage chamber 101 through the supply port 111 or the return port 107 to the toner supply chamber 102 is excessive, the toner T pushed up in the mountain shape by the return port 107 becomes the toner. The toner is returned from the supply chamber 102 to the toner storage chamber 101 through the return port 107. The toner agitating member 108 has a role of agitating the toner T in the toner supply chamber 102 and further supplying the toner T to the supply roller 44 and the developing roller 42 below.

The surface of the supply roller 44 is covered with a foam material having a structure having pores (cells), and the toner T supplied to the toner supply chamber 102 is efficiently attached and taken in, and the surface of the supply roller 44 is connected to the developing roller 42. Deterioration of the toner T due to pressure concentration at the contact portion is prevented. In addition, this foaming material is set to an electrical resistance value of 10 ³ to 10 ¹⁴ [Ω]. A supply bias is applied to the supply roller 44 and assists the operation of pressing the toner T preliminarily charged at the supply nip β in contact with the development roller 42 against the development roller 42. The supply roller 44 rotates in the counterclockwise direction in FIG. 36 as indicated by an arrow in FIG. 36 and supplies the toner T adhered to the surface so as to be applied to the surface of the developing roller 42.

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

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

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

  The thinned toner layer on the developing roller 42 is conveyed to the developing region α by the rotation of the developing roller 42, and the latent image formed by the bias applied to the developing roller 42 and the electrostatic latent image on the photoreceptor 2. The electrostatic latent image on the surface of the photoreceptor 2 is developed by moving to the surface of the photoreceptor 2 in accordance with the image electric field.

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

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

  Also in the developing device 4 according to the second embodiment, the configuration including the characteristic portion of the present invention with respect to the collection roller (supply roller 44) described in the first embodiment can be applied, and the configuration regarding the developing roller 42 is also possible. Applicable.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A developer such as toner T is carried on the surface, the surface moves endlessly, and a latent image on the surface of the latent image carrier is developed in a development area such as a development area α facing the latent image carrier such as the photosensitive member 2. A developer carrier such as a developing roller 42 for supplying and developing the developer; a developer accommodating portion such as a toner accommodating portion 43 that accommodates the developer; and the developer in the developer accommodating portion of the developer bearing member. In a developing device such as the developing device 4 provided with a developer supply means such as a supply roller 44 that supplies the surface, the developer is recovered from the surface of the developer carrying member that has passed through the developing region, and the recovered developer is applied to the surface. A developer collecting member such as a supply roller 44 that functions as a collecting roller that is carried on and moves endlessly, and an air pump 446 that generates an air flow that discharges from the inside to the outside of the endlessly moving surface of the developer collecting member The recovery member airflow generating means . According to this, as described in the first embodiment, the developer on the surface of the developer recovery member is blown off by this air flow, so that stress is applied to the developer carried on the surface of the developer recovery member. Can be separated from the developer collecting member.
(Aspect B)
In (Aspect A), the developer recovery member such as the supply roller 44 is supplied to the outer periphery of the shaft member such as the supply roller shaft 441. And a shaft member provided with a second cylindrical member such as an outer cylindrical member 441b whose inner peripheral surface faces the outer peripheral surface of the first cylindrical member such as the inner cylindrical member 441a. This is a double cylindrical member, and the first cylindrical member is fixed to the apparatus main body, and an opening such as an inner hole portion 443a is provided over the entire region in the axial direction of a part of the cylindrical circumferential direction. The second cylindrical member can be rotated with respect to the first cylindrical member by receiving rotational driving from the driving means, and the opening of the outer hole portion 443b and the like extends over the entire area in the circumferential direction and the axial direction of the cylindrical shape. Part is provided and the outer peripheral surface of the second cylindrical member A configuration in which the developer contacting layer is fixed, the recovery member airflow generating means such as an air pump 446 supplies the air flow to the inside cylindrical first cylindrical member. According to this, as described in the first embodiment, the position of the developer peeling from the developer recovery member can be designed and controlled by setting the position of the opening of the first cylindrical member.
(Aspect C)
In (Aspect A), the developer recovery member such as the supply roller 44 is supplied to the outer periphery of the shaft member such as the supply roller shaft 441. The developer contact layer is provided with a collecting roller, and the shaft member is a cylindrical member that can be rotated with respect to the apparatus main body when rotational driving is input from the driving means. An opening such as a hole 443 is provided over the entire area in the axial direction, and the developer contact layer is fixed to the outer peripheral surface of the shaft member. An air flow is supplied to the cylindrical inside of the member. According to this, as described in the above modification, the developer peeling position cannot be controlled by design, but compared to the aspect B, the configuration is less expensive and does not give stress to the developer. Further, it is possible to realize a configuration in which the developer is separated from the developer recovery member.
(Aspect D)
In any one aspect of (Aspect A) to (Aspect C), an environmental condition detection unit such as a thermohygrometer for detecting a use environmental condition is provided, and an air pump 446 or the like is provided based on the detection result of the environmental condition detection unit. The strength of the airflow generated by the recovery member airflow generation means is controlled. According to this, as described in the first embodiment, even if the adhesive force between the developer and the developer recovery member increases due to the environmental variation, the environmental variation is detected and the flow rate of the developer is increased by increasing the air flow rate. The peel strength can be increased.
(Aspect E)
In any one of (Aspect A) to (Aspect D), an image area ratio detection unit such as a control unit 700 that detects an image area ratio of an image developed by inputting image information used in the exposure apparatus 6 or the like. And the strength of the airflow generated by the recovery member airflow generation means such as the air pump 446 is controlled based on the detection result of the image area ratio detection means. According to this, as described in the first embodiment, the efficiency of peeling off the developer from the developer recovery member is maintained even when the output of the low image area ratio with low developer consumption continues. be able to.
(Aspect F)
(Aspect A) In any one aspect of (Aspect E), output number detection means such as a control unit 700 that detects the output amount of a developed image is provided, and air is generated based on the detection result of the image area ratio detection means. The strength of the airflow generated by the recovery member airflow generation means such as the pump 446 is controlled. According to this, as described in the first embodiment, even when the total number of output sheets increases and the deterioration of the developer progresses, the efficiency of the developer peeling from the developer collecting member can be maintained. it can.
(Aspect G)
In any one of (Aspect A) to (Aspect F), the surface of the developer carrying member such as the developing roller 42 is provided with a regular concavo-convex shape, is in contact with the surface of the developer carrying member, and the development region α And a regulating member such as a doctor blade 45 that regulates the amount of developer toward the developing area. According to this, as described in the first embodiment, the developer carrying amount is substantially stabilized over the surface movement direction of the developer carrying member, and the volume of the recess is set to a volume carrying a desired amount of developer. As a result, a desired amount of developer can be conveyed to the development area. In addition, in a developing device using a developer carrier having irregularities on the surface, the developer that has passed through the development region without contributing to development after being accommodated in the recess is again retained in the recess. If the frictional charging is further caused by the rubbing by the regulating member or other members, the developer may be a highly charged developer as compared with the other developer newly accommodated in the recess. When the ratio of such highly charged developer in the developer on the developer carrier increases, the latent image moves to the latent image in the development region due to the potential difference between the surface of the developer carrier and the latent image on the latent image carrier. There is a possibility that the amount of the developer is reduced, and developability is deteriorated due to accumulation of the driving time of the developing device. On the other hand, by providing a developer recovery member, it is possible to prevent the developer that has passed through the development region from remaining in the concave portion, and to use a developer carrier having irregularities on the surface. Thus, it is possible to achieve both the conveyance of a desired amount of developer to the development area and the maintenance of developability over time.
(Aspect H)
At least a latent image carrier such as the photosensitive member 2, charging means such as a charging member 3 for charging the surface of the latent image carrier, an exposure device 6 for forming an electrostatic latent image on the latent image carrier, and the like. In the image forming apparatus such as the copier 500 having the latent image forming means and the developing means for developing the electrostatic latent image into a toner image, the developing means of [Aspect A] to [Aspect G] Any one of the developing devices is used. According to this, as described in the first embodiment, the developer carried on the surface of the developer collecting member can be separated from the developer collecting member without applying stress to the developer collecting member. It is possible to provide an image forming apparatus capable of creating a stable image over a wide range.
(Aspect I)
In (Aspect H), a plurality of developing devices such as the developing device 4 are provided, and a plurality of toner images developed by the plurality of developing devices are superimposed on a toner image carrier such as an intermediate transfer belt 7 that carries a toner image. Perform image formation. According to this, as described in the first embodiment, it is possible to provide an image forming apparatus capable of creating a stable image over time even in image formation in which a plurality of color toner images such as full color images are superimposed. .
(Aspect J)
At least a latent image carrier and a developing unit in an image forming apparatus such as a copying machine 500 including a latent image carrier such as the photosensitive member 2 that carries the latent image and a developing unit that develops the latent image on the latent image carrier. In a process cartridge such as the process cartridge 1 that is configured to be held in a common holding body as a unit and detachably attached to the image forming apparatus main body, any one of [Aspect A] to [Aspect G] One embodiment of the developing device is used. According to this, as described in the first embodiment, the developer carried on the surface of the developer collecting member can be separated from the developer collecting member without applying stress to the developer collecting member. Thus, the developing device capable of creating a stable image can be removed from the apparatus main body together with other members constituting the process cartridge, and the exchange of the developing device capable of creating a stable image can be improved.

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Photoconductor 4 Developing apparatus 7 Intermediate transfer belt 12 Fixing apparatus 41 Developing casing 42 Developing roller 44 Supply roller 45 Doctor blade 100 Printer part 200 Paper feed part 300 Scanner part 400 Toner bottle 440 Supply roller cylindrical part 441 Supply roller shaft 441a Inner cylindrical member 441b Outer cylindrical member 443a Inner hole 443b Outer hole 443 Hole 445 Air transport pipe 446 Air pump 500 Copying machine 600 Printer 700 Controller

JP 2009-109604 A Japanese Patent No. 3789061

Claims (10)

A developer carrying member that carries the developer on the surface, moves the surface endlessly, and supplies the developer to the latent image on the surface of the latent image carrying member in a developing region facing the latent image carrying member;
A developer accommodating portion for accommodating the developer therein;
In a developing device comprising developer supplying means for supplying the developer in the developer accommodating portion to the surface of the developer carrying member,
A developer collecting member that collects the developer from the surface of the developer carrying member that has passed through the developing region, and carries the collected developer on the surface and moves endlessly;
A developing device comprising: a recovery member airflow generation means for generating an airflow discharged from the inner side to the outer side of the endlessly moving surface of the developer recovery member. The developing device according to claim 1.
The developer recovery member is a recovery roller provided with a developer contact layer on the outer periphery of the shaft member that allows air current to pass from the inside toward the outside and contacts the developer,
The shaft member is a double cylindrical member provided with a second cylindrical member whose inner peripheral surface faces the outer peripheral surface of the first cylindrical member,
The first cylindrical member is fixed with respect to the apparatus main body, and an opening is provided over the entire region in the axial direction of a part of the cylindrical circumferential direction.
The second cylindrical member can be rotated with respect to the first cylindrical member by receiving rotational driving from the driving means, and an opening is provided over the entire area in the circumferential direction and the axial direction of the cylindrical shape.
The developer contact layer is fixed to the outer peripheral surface of the second cylindrical member,
The developing device according to claim 1, wherein the recovery member airflow generation means supplies an airflow to a cylindrical inner side of the first cylindrical member. The developing device according to claim 1.
The developer recovery member is a recovery roller provided with a developer contact layer on the outer periphery of the shaft member that allows air current to pass from the inside toward the outside and contacts the developer,
The shaft member is a cylindrical member that can rotate with respect to the apparatus main body when rotational drive is input from the driving means, and an opening is provided over the entire area in the cylindrical circumferential direction and the axial direction.
The developer contact layer is fixed to the outer peripheral surface of the shaft member,
The developing device according to claim 1, wherein the recovery member airflow generating means supplies an airflow to a cylindrical inner side of the shaft member. The developing device according to any one of claims 1 to 3,
An environmental condition detection means for detecting the use environmental condition is provided,
A developing device characterized in that the strength of the airflow generated by the recovery member airflow generation means is controlled based on the detection result of the environmental condition detection means. In the developing device according to any one of claims 1 to 4,
An image area ratio detection means for detecting the image area ratio of the developed image is provided.
A developing device that controls the strength of the airflow generated by the recovery member airflow generation means based on the detection result of the image area ratio detection means. The developing device according to any one of claims 1 to 5,
Provided with output number detection means for detecting the output amount of the developed image,
A developing device that controls the strength of the airflow generated by the recovery member airflow generation means based on the detection result of the image area ratio detection means. The developing device according to any one of claims 1 to 6,
The surface of the developer carrying member has a regular uneven shape,
And a regulating member that regulates the amount of the developer that contacts the surface of the developer carrying member and moves toward the developing region. At least a latent image carrier;
Charging means for charging the surface of the latent image carrier;
Latent image forming means for forming an electrostatic latent image on the latent image carrier;
In an image forming apparatus having developing means for developing the electrostatic latent image into a toner image,
An image forming apparatus using the developing device according to claim 1 as the developing unit. The image forming apparatus according to claim 8.
An image forming apparatus comprising: a plurality of the developing devices, and performing image formation by superimposing a plurality of toner images developed by the plurality of developing devices on a toner image carrier that carries a toner image. In an image forming apparatus comprising a latent image carrier that carries a latent image and a developing unit that develops the latent image on the latent image carrier, at least the latent image carrier and the developing unit are shared as one unit. In a process cartridge configured to be held in a holding body and detachable integrally with the image forming apparatus main body,
A process cartridge using the developing device according to claim 1 as the developing means.

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