JP2009020276A - Developing device, process cartridge, and image-forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent toner from scattering due to an excessive increase in pressure at the end part in the length direction of the developer-carrying body of a developing device. <P>SOLUTION: A developing device is provided with: a developing roller 51 which carries a developer on it and conveys the developer to a part facing a photoreceptor; and a case 50 which accommodates the developer including at least a toner and has an aperture part at the part facing the photoreceptor. In this case, an air filter 62 for collecting the toner is provided in the gap between the case 50 and the end part in the length direction of the developing roller 51 to discharge an air current flowing toward the end part through the air filter 62. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and a developing device and a process cartridge employed in the image forming apparatus.

  Conventionally, since the weakly charged toner in the developing device is not easily subjected to electrostatic restraining force, it floats in the device by riding on the air flow generated in the device due to the movement of the developer due to the rotation of the developing roller and the developer stirring member. In addition, there is a problem that the air travels outside the developing device in an air current. In order to prevent such toner scattering from the developing device, a seal member is generally provided for sealing a gap between the components constituting the developing device. However, even if a seal member is provided, the surrounding air is sucked into the device due to the generated air flow and the internal pressure inside the device rises. There is a problem that the floating toner is ejected. In particular, in recent high-speed image forming apparatuses, since the number of rotations of the developing roller is high, the pressure increase in the apparatus is large, and a finer small-diameter toner is used for the purpose of improving the image quality. The above-mentioned problems are not negligible.

  In order to suppress the increase in internal pressure in the developing device and suppress the ejection of toner from the developing device, the applicant of the present invention provides an opening having a filter for preventing toner leakage in the developing container in Patent Document 1. Has proposed. This is by discharging the airflow in the developing device through the opening to the outside of the device to suppress the increase in internal pressure in the developing device, and collecting floating toner on the airflow and collecting it with the filter of the opening, This suppresses the ejection of toner from the developing device.

JP 2007-148335 A

  However, in the developing device of Patent Document 1, toner may be locally ejected from both ends in the longitudinal direction of the developing roller. Generally, the developer is carried and transported in the image forming area of the developing roller, but the developer is not carried and transported at both ends of the developing roller. A strong air flow is generated in the image forming area of the developer as the developer moves, and the surrounding air is sucked in to increase the pressure. On the other hand, no airflow is generated at both ends of the developing roller due to the movement of the developer, but the airflow caused by the air sucked into the image forming area is pushed toward the end sealed by the end seal member and conversely at the end. Pressure is excessive. For this reason, it becomes easy for the toner to be ejected from a slight gap with insufficient sealing performance at the end. It is also conceivable to improve the sealing performance by increasing the sealing property by adding a sealing member between the end portion of the developing roller and the developing container. However, it is difficult to completely seal the gap between the developing roller, which is a rotating body, and the developing container. In the case where there is no means for suppressing the increase in the internal pressure in the developing device as in Patent Document 1, the pressure increase at the end is further large and the toner is likely to be ejected.

  The present invention has been made in view of the above-described background, and an object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus that suppress toner scattering due to excessive pressure at the end of the developing device. Is to provide.

In order to achieve the above object, the invention of claim 1 contains a developer container containing at least a toner and having an opening at a portion facing the image carrier, and carrying the developer in the developer container. In the developing device including the image carrier and the developer carrier that is conveyed to the opposite portion by rotation, air that collects the toner is collected in a gap between the developer container and a longitudinal end of the developer carrier. A filter is provided.
According to a second aspect of the present invention, in the developing device of the first aspect, an air filter that collects the toner is provided at a position of the developer container facing the longitudinal end of the developer carrier. It is a feature.
According to a third aspect of the present invention, in the developing device of the first or second aspect, the pressure loss characteristic of the air filter is 5 × 10 ³ [Pa] or less at a wind speed of 5 [cm / s]. Is.
According to a fourth aspect of the present invention, in the developing device according to the first, second, or third aspect, the developer container is covered with an air filter that collects the toner at a position above the developer carrier. A feature is that an opening is provided.
According to a fifth aspect of the present invention, the developing device according to any one of the first, second, third, and fourth aspects and the image carrier are integrally formed and are detachable from the image forming apparatus. It is.
According to a sixth aspect of the present invention, the developing device according to any one of the first, second, third, or fourth aspect is provided.
The invention of claim 7 is characterized in that the process cartridge of claim 5 is provided.
The invention of claim 8 is the image forming apparatus of claim 6 or 7, wherein the toner of the developer used in the developing device is at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, and a colorant. The toner is obtained by crosslinking and / or extending a toner material liquid in which a release agent is dispersed in an organic solvent in an aqueous medium.

  In the present invention, an air filter having good air permeability is provided in the gap between the developing container and the end portion in the longitudinal direction of the developer carrier, instead of a seal member that seals the gap. This air filter collects the floating toner that reaches the end portion by riding on the air flow and exhausts the air flow that has flowed toward the end portion to the outside. Therefore, it is possible to prevent an excessive increase in pressure at the end portion and to suppress the ejection of toner from the apparatus.

  According to the present invention, there is an excellent effect that toner scattering due to excessive pressure at the end of the developing device can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing a color copying machine as an image forming apparatus, and FIG. 2 is an enlarged view showing an image forming unit thereof.
As shown in FIG. 1, the image forming units 6Y and 6M corresponding to the respective colors (yellow, magenta, cyan, black) so as to face the lower surface of the intermediate transfer belt 8 as an unfixed image carrier of the intermediate transfer unit 10. , 6C, 6Bk are juxtaposed. Since the four image forming units 6Y, 6M, 6C, and 6Bk installed in the apparatus main body 100 have substantially the same structure except for the color of the toner used in the image forming process, the image forming unit in FIG. In the drawing, the alphabets (Y, M, C, Bk) of reference numerals in the section 6, the photosensitive drum 1, and the primary transfer bias roller 9 as the primary transfer unit are omitted.

As shown in FIG. 2, the image forming unit 6 includes a photosensitive drum 1 as an image carrier, a charging unit 4 disposed around the photosensitive drum 1, a developing device 5 as a developing unit, and a cleaning unit 2. (Only the developing device 5 is shown in FIG. 1). An image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1, and a desired toner image is formed on the photosensitive drum 1.
The photosensitive drum 1, the charging unit 4, the developing device 5, and the cleaning unit 2 constituting the image forming unit 6 are each configured to be detachably installed on the image forming apparatus main body 100. Each is replaced with a new one when it reaches the end of its life.
In the present embodiment, the photosensitive drum 1, the charging unit 4, the developing device 5, and the cleaning unit 2 constituting the image forming unit 6 are each a single unit, but these are integrated into the apparatus main body 100. It can also be a process cartridge that is detachably installed. In this case, workability when performing maintenance of the image forming unit 6 is improved.

The photosensitive drum 1 is rotated in a clockwise direction in FIG. 2 by a driving unit (not shown), and the surface of the photosensitive drum 1 is uniformly charged by the charging roller 4a at the position of the charging unit 4 (charging). Process).
Thereafter, the surface of the photosensitive drum 1 reaches an irradiation position of a laser beam L emitted from an exposure unit (not shown), and an electrostatic latent image is formed by exposure scanning at this position.
Thereafter, the surface of the photosensitive drum 1 reaches a position facing the developing device 5, and the electrostatic latent image is developed at this position to form a desired toner image (developing process).
Thereafter, the surface of the photosensitive drum 1 reaches a position facing the intermediate transfer belt 8 and the primary transfer bias roller 9, and the toner image on the photosensitive drum 1 is transferred onto the intermediate transfer belt 8 at this position. (Primary transfer process).
At this time, a small amount of untransferred toner remains on the photosensitive drum 1.

Thereafter, the surface of the photoreceptor 1 reaches a position facing the cleaning unit 2, and untransferred toner remaining on the photoreceptor drum 1 is collected by the cleaning blade 2a at this position (cleaning step). After cleaning, the electric potential of the surface of the photosensitive drum 1 is initialized by the neutralizing roller 11.
Thus, a series of image forming processes performed on the photosensitive drum 1 is completed.

  As shown in FIG. 1, the image forming process described above is performed by each of the four image forming units 6Y, 6M, 6C, and 6Bk. That is, a laser beam L based on image information from an exposure unit (optical writing device) (not shown) disposed below the image forming unit is applied to the photosensitive drums of the image forming units 6Y, 6M, 6C, and 6Bk. Irradiated towards. Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

The four primary transfer bias rollers 9Y, 9M, 9C, and 9Bk respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1Bk to form a primary transfer nip. The primary transfer bias rollers 9Y, 9M, 9C, and 9Bk are applied with a transfer bias having a polarity opposite to the polarity of the toner.
The intermediate transfer belt 8 runs in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9Bk. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1Bk are primarily transferred while being superimposed on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 onto which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19 as a secondary transfer unit. The color toner image formed on the intermediate transfer belt 8 is transferred onto a transfer sheet P as a recording medium conveyed to the secondary transfer nip position.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.
A plurality of transfer sheets P are stored in a paper feeding unit 26 disposed in the lower part of the apparatus main body 100, and are separated and fed one by one by a paper feeding roller 27. The fed transfer paper P is temporarily stopped by the registration roller pair 28, and after the oblique deviation is corrected, it is conveyed toward the secondary transfer nip by the registration roller pair 28 at a predetermined timing. Then, a desired color image is transferred onto the transfer paper P at the secondary transfer nip.

The transfer paper P onto which the color image has been transferred at the position of the secondary transfer nip is conveyed to the fixing unit 20, where the color image transferred to the surface is fixed by heat and pressure generated by the fixing roller and the pressure roller. The
After the fixing, the transfer paper P is discharged as an output image to the paper discharge unit 30 formed on the upper surface of the apparatus main body by the paper discharge roller pair 29 and stacked. Thus, a series of image forming processes in the image forming apparatus is completed.
In FIG. 1, reference numeral 31 denotes a toner replenishing unit, and 32 denotes a reading unit.

Next, the configuration and operation of the developing device 5 in the image forming unit 6 will be described in more detail.
As shown in FIG. 2, the developing device 5 includes a developing roller 51 as a developer carrying member facing the photosensitive drum 1, a doctor blade 52 as a developer regulating member installed below the developing roller 51, a developer Two conveying screws 55 and 56 as developer agitating members disposed in the accommodating portions 53 and 54, a toner concentration sensor 57 (see FIG. 4) for detecting the toner concentration in the developer G, and above the developing roller 51 A case 50 serving as an upper wall covering the surface, an opening 50a provided in the case 50 so as to communicate with the outside of the apparatus, a filter 61 provided in the opening 50a, and a side opposite to the side facing the photosensitive drum 1 of the developing roller 51 It is comprised by the wall part 58 etc. as a side wall integrally provided in case 50 so that the side of this may be covered. The opening 50a and the filter 61 constitute an exhaust mechanism.
In the developer accommodating portions 53 and 54, a two-component developer G composed of a carrier and a toner is accommodated.

The developing roller 51 includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. As shown in FIG. 3, the magnet of the developing roller 51 has five magnetic poles, P1 to P5.
By rotating the sleeve around the magnet on which the five magnetic poles are formed, the developer G moves on the developing roller 51 (on the sleeve) with the rotation. Radial line segments attached to the developing roller 51 indicate positions where the magnetic forces of the P1 to P5 poles peak.

Specifically, in the region from the P4 pole to the P5 pole of the developing roller 51, both magnetic poles act on a carrier as a magnetic material, and the developer G accommodated in the developer accommodating portion 53 is carried on the developing roller 51. Is done. Part of the developer G carried on the developing roller 51 is scraped off at the position of the doctor blade 52 and returned to the developer containing portion 53.
On the other hand, the developer G carried on the developing roller 51 through the gap with the doctor blade 52 rises at the position of the P1 pole, and the toner in the developer G is a latent image on the photosensitive drum 1. Adhere to. In the region passing through the P1 pole and reaching the P2 pole, as will be described later, gas (air) flows from the developing roller 51 carrying the developer G after the developing process and the case 50 (gap 60). .
Further, in the region from the P3 pole to the P4 pole constituting the agent separating pole, the repulsive magnetic field formed by both magnetic poles having the same polarity acts on the carrier, and after the developing process carried on the developing roller 51. The developer G is detached from the developing roller 51. The detached developer G is returned again to the developer container 53 and circulates in the developer containers 53 and 54. Such a flow of the developer G is repeated.

The magnetic flux density between the P3 pole and the P4 pole is formed to be 10 mT or less. In this way, a repulsive magnetic field having the same polarity is formed so that the magnetic flux density between the poles is reduced, so that the developer passing through the P3 pole is blown off from the developing roller 51. It falls into the housing part 53.
Thereby, the gas above the developer accommodated in the developer accommodating portion 53 receives a strong dynamic pressure, and is urged by this dynamic pressure, so that the gas is efficiently discharged from the opening 50a. Here, since the opening 50a is disposed above the developer accommodating portion 53 and is disposed at a position deviated from the position where the developer falls, the developer that jumps up due to the falling of the developer is prevented. Problems that reach the opening 50a can be suppressed.

The developing roller 51 is installed so that a part of the developing roller 51 is exposed to the opening of the developing device 5 provided at a position facing the photosensitive drum 1. A case 50 made of a resin material or the like is installed above the developing roller 51 so as to cover the developing roller 51.
A doctor blade 52 is installed below the developing roller 51 (below the horizontal axis of coordinates with the rotation center of the developing roller 51 as the origin). By installing the doctor blade 52 below the developing roller 51 in this way, as will be described later, a gas flow path from between the developing roller 51 and the case 50 to the opening 50a is formed in the developer accommodating portion 53. , 54 can be secured without being blocked by the developer G in the inside.

The case 50 installed above the developing roller 51 is provided with a wall 58 and an opening 50a. The wall portion 58 is installed so as to cover the vicinity of the region from the P3 pole to the P4 pole through the P2 pole of the developing roller 51.
The opening 50a is provided at a position via the wall 58 with respect to the developing roller 51 and at a position above the developer containing portion 53 that is not buried in the developer G so as to communicate with the outside of the apparatus. Accordingly, a gas flow path (flow path indicated by a broken line arrow in FIGS. 2 and 3) from between the developing roller 51 and the case 50 to the opening 50a can be secured.

A filter 61 is installed in the opening 50a so as to cover the opening 50a.
The filter 61 is made of a porous material such as urethane foam or nonwoven fabric, collects toner entering from the inside of the apparatus, and allows air to pass to the outside of the apparatus.
Thereby, when the gas inside the apparatus (inside the developing section) is discharged from the opening 50a, it is possible to prevent toner scattering outside the apparatus (outside the developing section).
As shown in FIG. 2, the two developer accommodating portions 53 and 54 are separated from each other by a partition member 70 except for both ends in the longitudinal direction (the direction perpendicular to the paper surface in FIG. 2).
Conveying screws 55 and 56 installed in the developer accommodating portions 53 and 54 convey the developer G in opposite directions. As a result, the developer G accommodated in the developer accommodating portions 53 and 54 circulates between the developer accommodating portions 53 and 54 in the longitudinal direction.
As shown in FIGS. 4 and 5, a toner replenishing port 44 is connected above one developer accommodating portion 54. A toner conveying device (not shown) that conveys toner from the toner replenishing unit 31 is connected to the toner replenishing port 44, and fresh toner is appropriately replenished in the developer containing unit 54.

The developing device 5 configured as described above operates as follows.
The sleeve of the developing roller 51 rotates in the direction of the arrow in FIG. As described above, the developer G carried on the developing roller 51 by the magnetic field formed by the magnet moves on the developing roller 51 as the sleeve rotates.
The developer G in the developing device 5 is adjusted so that the toner ratio (toner concentration) in the developer G is within a predetermined range. Specifically, the toner is replenished from the toner conveying device into the developer accommodating portion 54 via the toner replenishing port 44 according to the toner consumption in the developing device 5.

The toner replenished in the developer accommodating portion 54 circulates through the two developer accommodating portions 53 and 54 while being mixed and stirred together with the developer G by the second conveying screw 56 and the first conveying screw 55.
The toner in the developer G is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51 together with the carrier by the magnetic force formed on the developing roller 51.
The developer G carried on the developing roller 51 is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52. Then, after the developer G on the developing roller 51 is regulated to an appropriate amount at this position, the developer G is conveyed to a position facing the photosensitive drum 1 (development region).
The toner is attracted to the latent image formed on the photosensitive drum 1 by the electric field formed in the development area. Thereafter, the developer G remaining on the developing roller 51 sequentially passes through the surface facing the case 50 and the surface facing the wall 58 as the sleeve rotates. Further, the developer G on the developing roller 51 reaches above the developer containing portion 53 and is detached from the developing roller 51 at this position.

In the series of operations of the developing device 5 described above, a gas flow path indicated by a broken-line arrow in FIG.
That is, the gas flowing from between the developing roller 51 and the case 50 passes through the surface facing the case 50 and the surface facing the wall 58 as the developing roller 51 rotates, and the tip of the wall 58. To. And the gas which flowed in in the apparatus goes around the front-end | tip part of the wall part 58, and is discharged | emitted out of the apparatus from the opening part 50a in which the filter 61 was installed.

Thus, in the developing device 5, the gas flow path indicated by the broken line arrow in FIG. 2 is stably formed. That is, a gas is introduced from between the developing roller 51 and the case 50 installed thereabove, and the introduced gas is guided to the opening 50 a without being blocked by the developer G accommodated in the developer accommodating portion 53. It is discharged out of the apparatus via 61.
As a result, the toner floating in the developing device 5 is transported to the opening 50 a along with the gas in the developing device 5 and forcedly formed in the developing device 5, and is reliably collected by the filter 61. be able to. Thus, toner scattering outside the apparatus in the developing unit 5 is suppressed.

  However, in the developing device 5, toner scattering may occur locally from both ends of the developing roller 51. In the developing device 5, since the magnet built in the developing roller 51 is shorter than the length of the developing roller 51, the developer is not conveyed at both ends of the developing roller that are outside the magnetic force range. Therefore, in the region within the magnetic force range in which the developer is conveyed, an air flow is generated by the surrounding gas that is caught in the developer and sucked into the apparatus. On the other hand, almost no airflow is generated by the movement of the developer at both ends of the developing roller that is outside the magnetic force range, but the airflow in the magnetic force region is pushed against the end sealed by the end seal member, and conversely The pressure at the end is excessive. For this reason, it becomes easy for the toner to be ejected from a slight gap with insufficient sealing performance at the end.

Therefore, in the developing device 5 of the present embodiment, the air filter 62 is provided so as to fill the gap between the peripheral surface of the developing roller 51 and the case 50 at the end of the developing roller 51. FIG. 5 is a sectional view of the developing device 5 provided with the air filter 62. The air filter 62 has a function of allowing the air to pass through while collecting the toner in the same manner as the filter 61. By exhausting the airflow flowing toward the end portion, the pressure at the end portion is released. be able to. The characteristic value of pressure loss representing the air permeability of the air filter is preferably 5 × 10 ³ [Pa] or less at a wind speed of 5 [cm / s].

  Further, an air filter 63 is provided in a region of the case 50 facing the end portion of the developing roller 50. FIG. 6 is a perspective view of the developing case provided with the air filter 63. In addition to the air filter 62 provided on the peripheral surface of the developing roller 50, the air filter 63 is provided on the upper surface of the case 50, so that the airflow that has flowed toward the end portion can be exhausted more effectively. Can relieve the pressure. Thereby, it is possible to suppress the ejection of toner from the end portion.

In FIG. 7, the developing device 5 equipped with the conventional end seal member, the pressure release filter 61, the air filter 62, and the air filter 63 is driven alone for a certain period of time and intentionally scattered in a state where the toner concentration is increased. It is the experimental result which measured the amount of scattering at the time. As shown on the horizontal axis, the measurement was performed at three locations of F, C, and R in the longitudinal direction. Here, as a conventional end seal member, in the environment of urethane foam, wind speed 5.3 [cm / s], the particle collection efficiency of 0.1 [μm] is 99% or more, and the pressure loss is 10 ^4. [Pa (Pascal)] More than the above and those with very poor air permeability were used. The air filters 62 and 63 are non-woven fabrics having a particle collection efficiency of 5 [μm] of 90% or more and a pressure loss of 10 ² [pa] in an environment with a wind speed of 5.3 [cm / s]. Is used.

  As can be seen from the results of FIG. 7, this device is a conventional developing device using an end seal member, and by mounting a pressure relief filter 61, scattering of the central portion (most areas of the developer conveyance area) is prevented. Although it has been suppressed, it has not been prevented to the end. Thus, it was confirmed that providing the air filter 62 at the end portion is highly effective in preventing scattering from the end portion. Further, it has been confirmed that the addition of the air filter 63 at a position facing the end portion of the developing roller 51 of the case has a very high effect in preventing scattering from the end portion. Thus, by providing the air filter 62 and further the air filter 63, there is an excellent effect that toner scattering due to excessive pressure at the end of the developing device 5 can be suppressed.

Next, toner in the image forming apparatus will be described. The toner suitably used in the image forming apparatus of each of the above embodiments is a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. Is a toner obtained by crosslinking and / or elongation reaction in an aqueous solvent.
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 a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain 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; 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 polyvalent isocyanate 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 deteriorates, 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 polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

When reacting (PIC) and when reacting (A) and (B), a solvent may be used if 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 And those inert to isocyanates (PIC), such as tetrahydrofuran (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 full-color image forming apparatus 100 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 it 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.

(Coloring agent)
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 Carmin Min BS, 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% by weight, preferably 3 to 10% by weight, 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 salt or compound, tungsten simple substance or compound, fluorine activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, 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 is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline and petrolatum. And petroleum wax.
In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ^{−3 to 2} μm, and particularly preferably 5 × 10 ^{−3 to} 0.5 [μm]. Moreover, it is preferable that the specific surface area by BET method is 20-500 [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 stirring and mixing in the developing device to obtain the charge level, the fluidity-imparting agent is not detached from the toner, and good image quality that does not cause firefly and the like can be obtained, and the residual toner is further reduced. Is planned.
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 added 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, that is, repeated copying. Stable image quality can be obtained even if

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

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 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 Such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxytyl, 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 Of acid ester, 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 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 imidazole , Nitrogen-containing compounds such as ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, Cypropylene, 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, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed 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 applying strong agitation in the process of removing the organic solvent, the shape between the spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.
As described above, if a toner having a sharp particle size distribution and a uniform charging characteristic is used, non-uniformity of charging in the developing container is eliminated due to small particle variation.
Accordingly, the number of toners that easily scatter is reduced regardless of the presence or absence of an air current, so that the amount of toner scatter can be reduced as compared with conventional toners.

  In this way, the improvement of the toner reduces the generation of toner that tends to scatter in the first place, and the scattered toner is prevented by the air flow control by the exhaust mechanism as described above. In this way, it is possible to obtain a developing device that is much less susceptible to toner scattering than in the past, and it is possible to prevent image smearing and in-machine smearing due to the scattered toner, resulting in good images and maintenance. It is possible to provide an image forming apparatus excellent in performance.

As described above, the air filter 62 that collects toner is provided in the gap between the case 50 and the end portion in the longitudinal direction of the developing roller 51 as described in the present embodiment. The air filter 62 collects the floating toner that reaches the end portion by riding on the air current, and exhausts the air current flowing toward the end portion to the outside. Therefore, it is possible to prevent an excessive increase in pressure at the end portion and to suppress the ejection of toner from the apparatus.
Further, by providing an air filter 63 that collects similar toner at a position facing the end of the developing roller of the case, it is possible to more effectively prevent an excessive increase in pressure at the end and Toner ejection can be suppressed.
Further, as the air filters 62 and 63, those having good air permeability with a pressure loss characteristic of 5 × 10 ³ [Pa] or less at a wind speed of 5 [cm / s] can effectively increase the pressure at the end. It is possible to prevent the ejection of toner from the apparatus.
Further, by providing an opening 50a covered with an air filter 61 with good air permeability for collecting toner at a position above the developing roller 51 of the case, an increase in pressure inside the developing device can be prevented and the apparatus From the toner can be suppressed.
Further, the developing device 5 and the photosensitive member 1 are integrally formed so that the process cartridge can be attached to and detached from the image forming apparatus, thereby improving the maintainability.
Further, as a toner, 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 is dispersed in an organic solvent is crosslinked and / or extended in an aqueous medium. Toner obtained by reaction is used. This makes it possible to use a toner having a sharp particle size distribution and a uniform charging characteristic and the like, and since there is little variation in the particles, non-uniform charging in the developing container is eliminated and toner ejection from the apparatus can be suppressed.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. The expanded sectional view of an image creation part. The figure which shows the structure of the developing roller vicinity. The perspective view which shows the back | inner side part of a developing device. FIG. 3 is a cross-sectional view of a developing device in which an air filter is provided in a gap between end portions of a developing roller. The perspective view of the developing device which provided the air filter in the case facing a developing roller. The graph of the experimental result which shows the relationship between an air filter and a toner scattering amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 5 Developing device 6 Image forming part 50 Case 50a Opening part 51 Developing roller 55, 56 Conveying screw 58 Wall part as a side wall 61 Pressure release filter 62 Air filter 63 Air filter

Claims (8)

A developer container that contains at least a developer containing toner and has an opening at a portion facing the image carrier, and a developer carrier that carries the developer in the developer container and conveys the developer to the opposite portion by rotation. In a developing device comprising a body,
A developing device comprising an air filter for collecting the toner in a gap between the developing container and a longitudinal end of the developer carrying member.   2. The developing device according to claim 1, wherein an air filter that collects the toner is provided at a position of the developer container facing the longitudinal end of the developer carrier. 3. The developing device according to claim 1, wherein the air filter has a pressure loss characteristic of 5 × 10 ³ [Pa] or less at a wind speed of 5 [cm / s].   4. The developing device according to claim 1, wherein an opening covered with an air filter that collects the toner is provided at a position above the developer carrier of the developer container. Developing device.   5. A process cartridge, wherein the developing device according to claim 1, and the image carrier are integrally formed and are detachable from the image forming apparatus.   An image forming apparatus comprising the developing device according to claim 1.   An image forming apparatus comprising the process cartridge according to claim 5.   8. The image forming apparatus according to claim 6, wherein the developer toner used in the developing device contains at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an organic solvent. An image forming apparatus, which is a toner obtained by crosslinking and / or stretching reaction of a toner material liquid dispersed in an aqueous medium.

Images