JP2011027841A - Fixing device, image forming apparatus, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of forming an image less in image omission even on a paper having rough surface property (rough paper). <P>SOLUTION: The fixing device includes a plurality of nip parts composed of a pressurizing member and a counter member, and a conveyance means conveying a transfer material on which a toner is transferred to the nip parts. The toner shows a pressure-induced transformation behavior from a hard material to a soft material. The device includes a nip part FH and a nip part F1 in this order along the conveyance direction of the transfer material, in which the pressure P1 applied to the nip part F1 is less than the pressure PH applied to the nip part FH having the maximum pressure applied in the nip parts in the upstream side of the nip part F1 along the conveyance direction, and the nip width N1 at the nip part F1 exceeds the nip width NH at the nip part FH. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixing device, an image forming apparatus, and an image forming method.

Conventionally, a pressure fixing method using wax core toner or capsule toner has been reported as a heatless fixing technique aiming at low power consumption of a fixing device (see, for example, Patent Document 1 and Patent Document 2).
In addition, a technique for obtaining a high gloss image and realizing low power consumption has been proposed (see Patent Documents 3 to 5).

JP-A-55-166653 JP 59-172654 A JP 2009-9117 A JP 2004-139039 A Japanese Patent Laid-Open No. 2007-4051

  An object of the present invention is to provide a fixing device capable of forming an image with little image omission even on paper having rough surface properties (rough paper). Another object of the present invention is to provide an image forming apparatus including the fixing device and an image forming method using the fixing device.

Said subject was solved by the means as described in <1>, <5>, <6> below. It is described below together with <2> to <4> which are preferred embodiments.
<1> A plurality of nip portions each including a pressure member and a counter member are provided, and a transfer unit that transfers the transfer material onto which the toner has been transferred to the nip portion, the toner satisfies the following formula (1), A nip portion FH and a nip portion F1 are provided in this order in the transfer material conveyance direction, and the applied pressure P1 at the nip portion F1 is the maximum applied pressure in the nip portion upstream of the nip portion F1 in the conveyance direction. A fixing device, wherein the nip width N1 in the nip portion F1 is greater than the nip width NH in the nip portion FH.
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
(In the formula (1), T (10 MPa) represents a temperature at which the viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 10 MPa, and T (1 MPa) represents a viscosity of 10 ^{4 at} a flow tester applied pressure of 1 MPa. (It represents the temperature when Pa · s is reached.)

<2> The fixing device according to <1>, wherein the pressure member and / or the opposing member in the nip portion F1 includes an elastic layer.
<3> The fixing device according to <1> or <2>, wherein the nip portion F1 is provided on the most downstream side in the conveyance direction of the transfer material of the plurality of nip portions.
<4> In any one of <1> to <3>, including an endless belt disposed between the pressing member and the facing member along the pressing member and / or the facing member. The fixing device according to the description,
<5> An image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that forms an electrostatic latent image on the surface of the image carrier, and a toner image obtained by developing the electrostatic latent image with a developer. Development means for developing the toner image, transfer means for transferring the toner image formed on the surface of the image holding member to a transfer target, and fixing means for fixing the toner image transferred to the transfer target. An image forming apparatus comprising the fixing device according to claim 1 as the fixing unit.
<6> A charging step for charging the surface of the image carrier, a latent image forming step for forming a latent image on the surface of the charged image carrier, and a latent image formed on the surface of the image carrier at least with toner. A developing process for forming a toner image by developing with a developer containing the toner, a transfer process for transferring the toner image formed on the surface of the image carrier to the transfer target, and a toner image transferred to the transfer target A fixing step for fixing, wherein the toner satisfies the following formula (1), and in the fixing step, the toner is pressurized a plurality of times, pressurized with an applied pressure PH, and then pressurized with an applied pressure P1, and the PH and P1 satisfies PH> P1, where NH is a nip width to be pressurized with PH, and N1 is a nip width to be pressurized with P1, and N1> NH is satisfied.
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
(In the formula (1), T (10 MPa) represents a temperature at which the viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 10 MPa, and T (1 MPa) represents a viscosity of 10 ^{4 at} a flow tester applied pressure of 1 MPa. (It represents the temperature when Pa · s is reached.)

According to the invention described in <1>, there is provided a fixing device capable of forming an image with less image omission even on paper having rough surface (rough paper) as compared with the case where the present configuration is not provided. Provided.
According to the invention described in the above <2>, a fixing device with improved fixability can be provided as compared with a case where this configuration is not provided.
According to the invention described in <3> above, a fixing device in which the occurrence of curling of the transfer material is suppressed as compared with the case where the present configuration is not provided is provided.
According to the invention described in <4> above, toner offset and image shift are suppressed as compared with a case where no endless belt is provided.
According to the invention described in <5> above, an image forming apparatus capable of forming an image with less image omission even on paper having a rough surface (rough paper) as compared with the case where the present configuration is not provided. Is provided.
According to the invention described in <6> above, an image forming method capable of forming an image with less image omission even on paper having rough surface properties (rough paper) as compared with the case where the present configuration is not provided. Is provided.

1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment. 1 is a schematic cross-sectional view illustrating an embodiment of a fixing device. FIG. 3 is a schematic cross-sectional view showing another embodiment of the fixing device. FIG. 10 is a schematic sectional view showing still another embodiment of the fixing device. FIG. 10 is a schematic sectional view showing still another embodiment of the fixing device. It is a figure which shows the relationship between the flow tester application pressure in 25 degreeC, and the viscosity of a toner. It is a figure which shows the relationship between nip time and image gloss. It is a figure which shows the relationship between nip space | interval and image gloss increase. It is a figure which shows the relationship between the nip passage frequency and image gloss. It is a figure which shows the relationship between the nip passage frequency and rough paper missing grade.

The fixing device according to the present embodiment includes a plurality of nip portions each including a pressure member and a counter member, and includes a transport unit that transports a transfer material onto which toner has been transferred to the nip portion. 1) and has a nip portion FH and a nip portion F1 in this order in the conveyance direction of the transfer material. The applied pressure P1 at the nip portion F1 is in the nip portion upstream in the conveyance direction from the nip portion F1. Thus, it is less than the applied pressure PH of the nip portion FH having the maximum applied pressure, and the nip width N1 in the nip portion F1 exceeds the nip width NH in the nip portion FH.
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
(In the formula (1), T (10 MPa) represents a temperature at which the viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 10 MPa, and T (1 MPa) represents a viscosity of 10 ^{4 at} a flow tester applied pressure of 1 MPa. (It represents the temperature when Pa · s is reached.)
The image forming apparatus of the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that forms an electrostatic latent image on the surface of the image carrier, and the electrostatic latent image. Developing means for developing the toner image with a developer, transfer means for transferring the toner image formed on the surface of the image carrier onto the transfer target, and fixing the toner image transferred onto the transfer target. A fixing unit, and the fixing unit is provided as the fixing unit.
The image forming method of the present embodiment includes a charging step for charging the surface of the image carrier, a latent image forming step for forming a latent image on the surface of the charged image carrier, and a surface formed on the surface of the image carrier. A developing step of developing the latent image formed with a developer containing at least toner to form a toner image, a transfer step of transferring the toner image formed on the surface of the image holding member to the transfer target, and the transfer target A fixing step of fixing the toner image transferred to the body, wherein the toner satisfies the following formula (1), and in the fixing step, the pressure is applied a plurality of times and the applied pressure PH is applied, and then the applied pressure is applied. When P1 is pressurized, PH and P1 satisfy PH> P1, the nip width pressurized with PH is NH, and the nip width pressurized with P1 is N1,
N1> NH
It is characterized by satisfying.
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
(In the formula (1), T (10 MPa) represents a temperature at which the viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 10 MPa, and T (1 MPa) represents a viscosity of 10 at a flow tester applied pressure of 1 MPa). Represents the temperature at ⁴ Pa · s. )

In the pressure fixing method using the wax core toner and the capsule toner described in Patent Documents 1 and 2, the fluidity of the toner at the time of fixing may not be sufficient, or the shell may remain. It was not obtained. In addition, the toner having high pressure dependency needs to be nipped at a high pressure at the time of pressurization, and a sufficient nip time needs to be given, leading to an increase in the size and load of the apparatus.
According to the fixing method of the present embodiment, by fixing the toner having pressure fixability, the apparatus is reduced in size and reduced in power consumption by being configured to pressurize a plurality of times, and further, the nip width is reduced. By having a nip portion that is large and has a small applied pressure, the fixability to particularly rough paper (rough paper) is improved.

  As a result of intensive studies, the present inventors have found that the toner fluidity differs from that of a single nip when the toner having pressure fixability is fixed by multiple pressurizations (multi-stage pressure fixing). The present inventors have found that they can be held in a state without being completed, and have completed the present invention. This is because the pressure fluidity is derived from the composition of the resin constituting the toner, and is separated when the pressure is not applied to the binder resin of the toner (not compatible), and when the pressure is applied It is thought that this is due to the properties of baroplastics, which are only compatible. That is, when the pressure is released from the compatible state by pressurization, the phase separation state is obtained again. By performing the next pressurization before the phase separation is performed, the compatibility can be promoted. By giving a small amount of pressure in multiple times, fluidity of the resin that has not been recognized in the past can be obtained. Conceivable.

  Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment. The image forming apparatus shown in FIG. 1 is an intermediate transfer type image forming apparatus generally called a tandem type. This image forming apparatus includes a plurality of image forming units 30Y, 30M, 30C, and 30K that form toner images of respective color components by electrophotography. Further, a primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 30Y, 30M, 30C, and 30K to the intermediate transfer belt 15 is provided. Further, a secondary transfer unit 20 is provided that collectively transfers (secondary transfer) the superimposed toner image transferred onto the intermediate transfer belt 15 onto a sheet P that is a recording material (recording paper). Further, a fixing device 60 is provided for fixing the secondary transferred image on the paper. Furthermore, the control part 40 which controls operation | movement of each apparatus (each part) is provided.

  In the present embodiment, the following electrophotographic devices are sequentially arranged in each of the image forming units 30Y, 30M, 30C, and 30K. Around the photosensitive drum (image holding member) 11 that rotates in the direction of arrow A, a charger 12 that charges the photosensitive drum 11 is provided. Further, a laser exposure device 13 (the exposure beam is indicated by Bm in the drawing) for writing an electrostatic latent image on the photosensitive drum 11 is provided. Further, a developing device 14 is provided that stores toner of each color component and visualizes the electrostatic latent image on the photosensitive drum 11 with the toner. Further, a primary transfer roll 16 is provided for transferring each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 15 by the primary transfer unit 10. Further, a drum cleaner 17 for removing residual toner on the photosensitive drum 11 is provided. The intermediate transfer belt 15 is circulated and rotated (rotated) at a predetermined speed in the direction of arrow B shown in FIG. 1 by various rolls such as a drive roll 31 driven by a motor (not shown) having excellent constant speed. ing.

The primary transfer unit 10 includes a primary transfer roll 16 disposed to face the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. Then, the toner images on the respective photosensitive drums 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so that the toner images superimposed on the intermediate transfer belt 15 are formed.
The secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image carrying surface side of the intermediate transfer belt 15 and a backup roll 25. The secondary transfer roll 22 is disposed in pressure contact with the backup roll 25 with the intermediate transfer belt 15 interposed therebetween. Further, the secondary transfer roll 22 is grounded, a secondary transfer bias is formed between the secondary transfer roll 22 and the backup roll 25, and the toner image is secondarily transferred onto the sheet conveyed to the secondary transfer unit 20.

Next, a basic image forming process of the image forming apparatus according to the present embodiment will be described. In the image forming apparatus according to the present embodiment, image data is output from an image reading apparatus (IIT) (not shown) or the like. The image data is subjected to predetermined image processing by an image processing device (IPS) (not shown), converted into color material gradation data of four colors Y, M, C, and K, and output to the laser exposure unit 13. The
The laser exposure unit 13 irradiates the photosensitive drum 11 of each of the image forming units 30Y, 30M, 30C, and 30K with, for example, an exposure beam Bm emitted from a semiconductor laser in accordance with the input color material gradation data. Yes. After the surface of each photoconductive drum 11 is charged by the charger 12, the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of Y, M, C, and K colors by the developing devices 14 of the respective image forming units 30Y, 30M, 30C, and 30K. The toner image formed on the photoconductive drum 11 is transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photoconductive drums 11 and the intermediate transfer belt 15 come into contact with each other.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. At this time, the sheet conveyed by the conveying roll 52 and the like in time is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. The unfixed toner image carried on the intermediate transfer belt 15 is electrostatically transferred collectively onto the paper in the secondary transfer unit 20. Thereafter, the sheet on which the toner image has been electrostatically transferred is conveyed as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is provided on the downstream side of the secondary transfer roll 22 in the sheet conveyance direction. To 55. The conveyance belt 55 includes two support rolls and a belt stretched around the support rolls, and stably conveys the sheet to the fixing device 60 at an optimum conveyance speed.

  In the above description, a so-called tandem image forming apparatus has been described. However, the present embodiment is not limited to this, and may be applied to a rotary developing type (revolver developing type) image forming apparatus. .

Next, the fixing device 60 to which the exemplary embodiment is applied will be described.
FIG. 2 is a schematic sectional view showing an embodiment of the fixing device 60.
In FIG. 2, the fixing device 60 is made of SUS (stainless steel) with opposed rolls 1-1 to 1-3 and 2-1 to 2-3 having a pressure of 5 MPa (50 kgf / cm ² ) or more. The load is adjusted by a pressure mechanism (not shown) so that the nip width is 1 mm. Rolls 8 and 9 are formed by forming a silicone rubber layer, which is an elastic body layer having a thickness of 5 mm, on the surface of an aluminum roll having a diameter of 40 mm, and applying a load by a pressure mechanism (not shown) so that a nip width of 0.5 MPa or more is 5 mm. It is adjusted.
These pressurizing portions are arranged at intervals of 50 mm, and the belts 5 and 6 are stretched by belt stretch rolls 3 and 4, respectively.

The belts 5 and 6 are not particularly limited and may be appropriately selected from known belts used as endless belts in image forming apparatuses. From the viewpoint of suppressing toner sticking to the belt during fixing, the belts It is preferable to form an elastic layer, a release layer, etc. on the surface of the substrate.
For example, examples of the belt base material include polyimide resins, polyamideimide resins, polyester resins, polyamide resins, and fluorine resins. Among these, it is preferable to use polyimide resins and polyamideimide resins. . Moreover, it is preferable that the thickness of a belt base material is 0.02 mm or more and 0.2 mm or less.
In FIG. 2, as the belts 5 and 6, release layers are formed on a polyimide base layer having a thickness of 100 μm. As the release layer, silicone rubber having a thickness of 10 μm can be used. Each belt is rotationally driven in the direction of the arrow by a drive mechanism (not shown).

In the present exemplary embodiment, the fixing device is not particularly limited as long as it has a plurality of nip portions, and may have a heating unit, but it is preferable to perform fixing only by a pressing unit. By not having the heating means, it is preferable because fixing is performed with lower power consumption (low power consumption).
In the case where the fixing device of the present embodiment includes a heating unit, the heating temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and further preferably 70 ° C. or lower.
When fixing ordinary thermoplastic toner, a pressure unit of a fixing device is heated to, for example, about 150 ° C., and the toner is melted by heat and pressure. At that time, water contained in the paper or toner is heated to 100 ° C. or more, and water vapor is generated, resulting in poor adhesion between the paper, the toner, and the fixing member, and spotted defects due to water vapor in the fixed image. May occur. Therefore, in order to provide a plurality of pressurizing members adjacent to each other as in this embodiment, the pressure between the nip portions (pressurizing portions) between the rolls does not become lower than the water vapor pressure. It is necessary to take measures such as arranging a fixing member, and there are many design restrictions. In this embodiment, since the toner is fixed at a low heating temperature or without heating, image defects due to the generation of water vapor are suppressed, and the degree of design freedom is further improved.

In FIG. 2, the pressure member 1-1 and the opposing member 2-1 are paired to form a nip portion (pressure portion). The fixing device includes a plurality of pressure members and a plurality of opposing members. Prepare. However, the fixing device of the present embodiment is not limited to this as long as it has a plurality of nip portions (pressure portions).
For example, as shown in FIG. 3, it has one pressurizing member 1 and a plurality of opposing members 2-1, 2-2, 2-3, 9 facing this, and the opposing member 9 is It is good also as an opposing member which provides an elastic body layer on the surface, and as shown in FIG. 4, it has several pressurizing members 1-1, 1-2, 1-3, and 8 and pressurizing member 8 In addition, a pressure member in which an elastic body layer is provided on the surface of the roll may be provided, and one opposing member 2 facing the pressure member may be provided.
Among these, as shown in FIG. 2, it is preferable that the transfer material is conveyed linearly. This is preferable because deformation (curl or the like) of the transfer material is suppressed.

In FIGS. 2 to 4, the pressure member and the opposing member are both roll-shaped, but the present embodiment is not limited to this. As shown in FIG. 5, the pressure member may be a pressure roll not provided with an elastic body layer, the opposing member 9 may be an elastic fixing member, and the belt 6 may be supported by the surface, and is not particularly limited.
In FIG. 5, the pressing member 1-4 is pressed against the opposing member 9 that is an elastic member, so that a nip width wider than the nip portion upstream of the pressing member 1-4 and a small applied pressure can be obtained.
In FIG. 5, belt tension rolls 3 ′ and 4 ′ are provided downstream of the pressure member 1-4 and the counter member 9, respectively.

In the present embodiment, the fixing device has a plurality of nip portions. The number of nip portions is not particularly limited as long as it is 2 or more, but is preferably 2 to 5 from the viewpoint of energy saving and apparatus miniaturization.
2 to 4, four nip portions are formed. In FIG. 2, the pressure members 1-1, 1-2, 1-3, 8, and the opposing members 2-1, 2-2, The transfer material 7 having the toner transferred thereon is fixed by pressing (nip) between the pressing member and the opposing member.
In the present embodiment, the pressure member is present on the side of the transfer material on which the toner is held, and the opposite member is present on the side of the surface where the toner is not held.

In this embodiment, the fixing device has a nip portion FH and a nip portion F1 in this order in the conveyance direction of the transfer material, and the applied pressure P1 at the nip portion F1 is in the nip portion upstream in the conveyance direction from F1. It is less than the applied pressure PH of the nip portion FH having the maximum applied pressure.
Referring to FIG. 2, the nip portion F <b> 1 includes a pressure member 8 and a counter member 9. The three nip portions formed by the pressure member 1-1 and the counter member 2-1, the pressure member 1-2 and the counter member 2-2, and the pressure member 1-3 and the counter member 2-3 are Since the applied pressure is the same in all cases, the nip portion FH may be any of the three nip portions.
That is, in the present embodiment, at least upstream of the second and subsequent nth nip portions in the transport direction (1st to (n-1) th), a nip portion having a larger applied pressure than the nth nip portion. Exists.
As described later, PH is preferably 5 MPa or more, and P1 is preferably 0.02 to 0.1 times PH.

In the present embodiment, the nip width N1 in the nip portion F1 exceeds the nip width NH in the nip portion FH. Here, the nip width refers to the length in the conveyance direction of the pressing area between the pressure member and the opposing member.
As a method for measuring the nip width, for example, there is a method using a sheet of paper that is printed black on the entire surface (hereinafter referred to as “black sheet”). Specifically, in this method, the black paper is held between the pressure member and the opposing member for a predetermined time and then taken out, so that the portion of the black paper held by the pressure member and the opposing member is changed to another part. Compared to glossy. Then, the nip width is measured by measuring the glossy portion with a caliper or the like.
That is, N1> NH, and NH is not particularly limited, but is preferably 0.1 to 1.0 mm.
Further, N1 is preferably 2 to 10 times that of NH.

  In the present embodiment, a nip portion F1 having a low applied pressure and a wide nip width is provided downstream of the nip portion FH having a high applied pressure and a narrow nip width. In other words, the fluidity of the toner is enhanced by the nip portion FH having a high applied pressure and a narrow nip width in advance, and is fixed to the wide nip portion, so that it is high even for paper with rough surface properties (rough paper). Fixability can be obtained.

  In the present embodiment, it is preferable that the nip portion F1 exists at the most downstream side in the transfer material conveyance direction of the nip portion. By disposing F1 on the most downstream side, the sufficiently fluidized toner is fixed with a low pressure and a wide nip width, and deformation of the transfer material, particularly a recording medium (for example, paper) is suppressed. Therefore, it is preferable.

In the present embodiment, it is preferable that the pressure member and / or the opposing member of the nip portion F1 have an elastic layer.
Here, the elastic body layer is a layer having a hardness of 75 ° (JIS K 6253, type A durometer) or less. The hardness is preferably 15 to 30 °. As the elastic layer, it is preferable to use a material having a hardness in the above range and excellent durability. For example, silicone rubber, fluorine rubber, fluorosilicone rubber and the like can be mentioned. It is preferable to select the material, hardness, and thickness of the elastic layer so that a necessary nip pressure (applied pressure) and nip width can be obtained and high durability can be obtained.
In this embodiment, the fixing roll provided with an elastic layer on the surface is described in, for example, a method of adhering rubber around a metal roll, Japanese Patent Laid-Open No. 58-193135, or Japanese Patent Laid-Open No. 2-120882. As described above, there is a method in which a mold is installed around a metal core, and a liquid rubber material is injected and cured therein.
In this embodiment, instead of the elastic layer, the pressure member and the opposing member may be formed of a plate-like body having a wide nip width, and the applied pressure may be adjusted to be N1.

In the present embodiment, a plurality of peeling portions between the fixing device 60 and the transfer material 7 may exist, but as shown in FIG. 2, the peeling portion is preferably a single location. Here, the peeling portion means the number of locations where the transfer material and the fixing device are not bonded after the transfer material is conveyed to the fixing device. In FIG. 2, the transfer material 7 is transported to the fixing device 60 and is peeled off when being transferred from the fixing device 60. Therefore, there is one peeling portion.
Moreover, it is preferable to have an endless belt disposed between the pressure member and the counter member along the pressure member and / or the counter member. It is preferable to have an endless belt because a peeling portion between the fixing device and the transfer material is reduced, and toner offset and image displacement are reduced.
In the fixing member shown in FIG. 2, when the endless belt is not stretched, the peeling part is not the final peeling part between the fixing device 60 and the transfer material 7, but the pressure member 1-1 and the opposing member. Similarly, between the first nip portion constituted by 2-1 and the second nip portion constituted by the pressure member 1-2 and the opposing member 2-2, the second nip portion There are also peeling portions between the three nip portions and between the third nip portion and the fourth nip portion, and there are a total of four peeling portions including the final peeling portion.

In the present embodiment, it is preferable that at least one of the applied pressures in the nip portion is equal to or higher than a pressure P (10 ⁵ ) at which the flow tester melt viscosity of the toner becomes 10 ⁵ Pa · s. It is preferable that at least one of the applied pressures at the nip portion is P (10 ⁵ ) or more because the fixability is improved. That is, PH is preferably P (10 ⁵ ) or more.
In the present embodiment, the applied pressure is more preferably P (10 ⁵ ) or more in more nip portions among the applied pressures in a plurality of existing nip portions, and the applied pressure in all the nip portions excluding F1 is higher. More preferably, it is P (10 ⁵ ) or more.
The pressure P (10 ⁵ ) at which the flow tester melt viscosity becomes 10 ⁵ Pa · s is preferably measured at the in-machine temperature, but in this embodiment, it is measured at 25 ° C. for convenience.

In this embodiment, the total time T1 during which the toner is pressurized at a pressure P (10 ⁵ ) or higher at which the melt viscosity of the toner is 10 ⁵ Pa · s is equal to the image gloss saturation at the pressure P (10 ⁵ ). It is preferable that the time T0 or more to reach 80% of the point value G1.
The value of the image gloss saturation point and the pressure application time to reach the image gloss saturation point are measured by the following method.
In the present embodiment, the image gloss saturation point means a point at which an image gloss increase rate (an increase rate of the image gloss with respect to the nip time) is 0.2% / ms or less.
Specifically, 127 gsm of the top coat N is used as an evaluation sheet, the fixing pressure is constant at P (10 ⁵ ), the nip time is changed, the image gloss is measured, the nip time is plotted on the horizontal axis, and the image gloss is plotted on the vertical axis. As a graph, an image gloss increase rate (% / ms) is calculated from the slope (differential value) of the graph. At this time, pressurization is performed in one stage.
For the image gloss, a solid image is created by transferring cyan, magenta, and yellow toners on 4 g / m ² paper, and is incident on a gloss meter (trade name “VGS-SENSOR” manufactured by Nippon Denshoku Industries Co., Ltd.). Measure at an angle of 60 °.

In the present embodiment, the interval time I1 at which the pressure is applied at the pressure P (10 ⁵ ) or more in the nip portion is the image gloss saturation value G1 when the total pressure time is T1 and the pressurization interval is increased. It is preferable that the time to become 50% is not more than I0.
I0 will be described in further detail. As a measuring method of I0, the total pressurization time is made constant at T1, and the interval time is changed. At this time, the applied pressure is not particularly limited as long as it is P (10 ⁵ ) or more, but it is preferable to measure at the applied pressure used in the fixing device determined based on P (10 ⁵ ).
In this embodiment, when there are five nip portions, the pressurization time at one nip portion is (T1 / 5), and the pressurization time is adjusted by adjusting the interval between the nip portions and the conveyance speed. The interval time can be adjusted. The gloss of the obtained image is measured while changing the interval time. For the image gloss, a solid image is created by transferring cyan, magenta, and yellow toners on 4 g / m ² paper, and is incident on a gloss meter (trade name “VGS-SENSOR” manufactured by Nippon Denshoku Industries Co., Ltd.). Measure at an angle of 60 °.
When the interval time is increased, the glossiness tends to decrease. A graph is created with the interval time as the horizontal axis and the gloss as the vertical axis, and the interval time I0 at which the image gloss is 50% of G1 is obtained.
It should be noted that I0 is measured for each color, and I1 is preferably the shortest I0 or less.

(toner)
In the present embodiment, the toner (also referred to as an electrostatic charge image developing toner in the present specification) satisfies the formula (1).
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
In formula (1), T (1 MPa) represents the temperature at which the toner viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 1 MPa (10 kgf / cm ² ), and T (10 MPa) represents the flow tester applied pressure. This represents the temperature at which the toner viscosity is 10 ⁴ Pa · s at 10 MPa (100 kgf / cm ² ).
The expression “20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C.” is synonymous with “20 ° C. ≦ {T (1 MPa) −T (10 MPa)} ≦ 120 ° C.”, and “{T The value of (1 MPa) −T (10 MPa)} is synonymous with “20 ° C. or higher and 120 ° C. or lower”.

  When a resin having a high glass transition temperature (hereinafter also referred to as “high Tg resin”) and a resin having a low glass transition temperature (hereinafter also referred to as “low Tg resin”) form a micro phase separation state. The resin exhibits plasticizing behavior with respect to pressure, and exhibits fluidity even in a normal temperature region under a certain pressure or higher. Such a resin is sometimes called a baroplastic.

  When a pressure of a certain level or higher is applied to the toner containing baroplastic, the plasticizing fluidity is exhibited, and when a pressure lower than that is applied, the toner can behave in a solid state. As a result, high reliability is ensured in the development process, cleaning process, and the like other than the fixing process in the electrophotographic process.

  In addition, a toner having a small diameter such as 3 μm or less, which has been difficult to realize by providing high reliability, is also used. As a result, toner consumption can be reduced and high-definition images can be realized. As a result, it is possible to achieve both high image quality, reliability, and economy by reducing toner consumption. In the present embodiment, low-temperature fixability and high reliability are compatible by positively using the pressure plasticizing effect of baroplastic.

In the present embodiment, at a flow tester applied pressure of 1 MPa, the temperature T (1 MPa) at which the viscosity of the toner for developing an electrostatic charge image is 10 ⁴ Pa · s is preferably 60 ° C. or more, and preferably 80 to 120 ° C. It is more preferable. When T (1 MPa) is 60 ° C. or higher, the strength of the toner in the developing machine is excellent.

At a flow tester applied pressure of 10 MPa, the temperature T (10 MPa) at which the electrostatic charge image developing toner has a viscosity of 10 ⁴ Pa · s is preferably 80 ° C. or lower, more preferably 30 to 60 ° C. When T (10 MPa) is 80 ° C. or lower, sufficient fixability is obtained and the fixed image strength is excellent.

The T (1 MPa) and T (10 MPa) preferably satisfy a relationship of 30 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C.
When T (1 MPa) -T (10 MPa) is 30 ° C. or higher, the toner has excellent fixability and excellent fixed image strength. Further, when T (1 MPa) −T (10 MPa) is 120 ° C. or less, fixing failure can be suppressed and the fixed image strength is excellent.
In the present embodiment, 30 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 60 ° C. is preferable. It is preferable from the viewpoint of fixability to be within the above numerical range.

The flow tester measurement conditions here are as follows.
Using a flow tester CFT-500A manufactured by Shimadzu Corporation, a starting temperature of 19 ° C. to a maximum temperature of 170 ° C., a heating rate of 3 ° C./min, a preheating time of 300 sec, a cylinder pressure of 1 MPa (10 kgf / cm ² ) to 10 MPa (100 kgf / cm ² ), and the softened state when the temperature is increased at a constant speed under the conditions of die L × D = 1.0 mm × 1.0 mm is measured. As the sample, since it is difficult to separate only the resin of the toner, the toner itself is weighed and used. The plunger cross-sectional area is 10 cm ² . In the measuring method, as the temperature is increased at a constant speed, the sample is gradually heated and the outflow begins. When the temperature is further raised, the molten sample largely flows out, the plunger descending stops, and one measurement is completed. The outflow amount at each temperature is measured in increments of 3 ° C. from 19 to 170 ° C., and the apparent viscosity η ′ (Pa · s) is obtained. At this time, at a flow tester applied pressure of 1 MPa (10 kgf / cm ² ) and a flow tester applied pressure of 10 MPa (100 kgf / cm ² ), a temperature at which the apparent viscosity η ′ (Pa · s) is 1 × 10 ⁴ Pa · s is obtained. The difference is calculated.

As an example of the baroplastic, those having a microphase separation structure are preferable, and a copolymer having a block structure as described in JP-A-2007-114635 is more preferable. Hereinafter, the resin having a block structure will be described.
In the present embodiment, 80% by weight or more of the binder resin contained in the electrostatic image developing toner is preferably baroplastic, and more preferably 100% by weight is baroplastic.

(Copolymer having a block structure)
The electrostatic image developing toner used in the exemplary embodiment is preferably a toner containing a copolymer having a block structure (block copolymer).
The copolymer having a block structure is preferably a copolymer having a resin having a high glass transition temperature (block A) and a resin having a low glass transition temperature (block B).

(1) Block Copolymer Comprising Blocks Polymerized with Ethylenically Unsaturated Compound The electrostatic image developing toner of this embodiment includes a block copolymer composed of blocks polymerized with an ethylenically unsaturated compound. These block copolymers can be obtained by polymerizing various ethylenically unsaturated compounds.

The block copolymer is preferably a block copolymer including the following block A and block B. The glass transition point Tg (A) of the block A is preferably 60 ° C. or higher, and more preferably 70 to 110 ° C. Within the above range, the practical strength as a toner and the image strength after fixing are good.
Moreover, it is preferable that the glass transition point Tg (B) of the said block B is 20 degrees C or less, and it is more preferable that it is -100-10 degreeC. Within the above range, good fixability under pressure can be obtained.
It is preferable that the block A and the block B occupy 60% by weight or more of the entire block copolymer, more preferably 80 to 100% by weight, and the diblock copolymer comprising the block A and the block B More preferably, it is a polymer. When the content of the block A and the block B is within the above range, good fixability under pressure can be obtained.
Moreover, as a ratio of the block A and the block B, the total amount of the block A and the block B is 100% by weight, and the ratio of the block A is preferably 25 to 75% by weight, and 40 to 60% by weight. It is more preferable. Within the above range, the practical strength as a toner and the image strength after fixing are good.
The glass transition point Tg is measured by the method prescribed in ASTM D3418-82 when a differential scanning calorimeter (DSC) is used to measure from −80 ° C. to 150 ° C. at a rate of temperature increase of 10 ° C. per minute. The measured value.

  Furthermore, the difference (Tg (A) −Tg (B)) between the glass transition point Tg (A) of the homopolymer of block A and the glass transition point Tg (B) of the homopolymer of block B is 60 ° C. or more. Is preferred. Within the above range, sufficient pressure fixability can be obtained, and heat energy for fixing can be reduced.

In the present embodiment, the ethylenically unsaturated compound may be a compound having at least one ethylenically unsaturated bond, and is preferably an addition polymerizable compound, which is anionic polymerizable, cationic polymerizable, and radical polymerizable. Any one of coordination polymerizable compounds may be used, and among them, a radical polymerizable ethylenically unsaturated compound is more preferable.
Examples of radically polymerizable ethylenically unsaturated compounds that can be used in this embodiment include styrenes, (meth) acrylic acid esters (“(meth) acrylic acid ester” and the like are “acrylic acid ester and / or Synonymous with “methacrylic acid ester” and the like hereinafter, and the like), ethylenically unsaturated nitriles, ethylenically unsaturated carboxylic acids, vinyl ethers, vinyl ketones, olefins and the like.

  More specifically, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate , Β-carboxyethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and the like; Ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; Ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; Vinyl such as vinyl methyl ether and vinyl isobutyl ether Preferred examples include ethers; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; and olefins such as isoprene, butene and butadiene. As a block contained in the block copolymer, a homopolymer consisting of any one of these ethylenically unsaturated compounds, a copolymer obtained by copolymerizing two or more of these, and a mixture thereof are also included. used.

Examples of the ethylenically unsaturated compound that can be preferably used for the production of the block A having a Tg (A) of 60 ° C. or higher include styrenes such as styrene, parachlorostyrene, and α-methylstyrene. Among them, styrene is preferable. Can be used.
In addition, as the ethylenically unsaturated compound that can be preferably used for the production of the block B having Tg (B) of 20 ° C. or less, (meth) acrylic acid esters are preferably exemplified, and among them, acrylic acid esters are more preferable. Acrylic acid alkyl esters having an alkyl group of 1 to 8 carbon atoms are more preferable, and methyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and the like are particularly preferable.

In the preparation of block copolymers of these ethylenically unsaturated compounds, various living polymerization methods such as an ionic polymerization method and a living radical polymerization method are used, but in this embodiment, combinations of the monomers are used. It is preferable to use a living radical polymerization method because of its ease.
In this case, as the living radical polymerization method, existing methods such as NMRP (Nitroxide Mediated Radial Polymerization), ATRP (Atom Transfer Radical Polymerization), and RAFT (Reversible Addition Fragmentation Transfer) can be used. Among these, in this embodiment, the NMRP method is preferable.

  As the nitroxide compound used in the NMRP method, a known nitroxide compound used in the living radical polymerization method is used. Specifically, JP 2004-307502 A, JP 2005-126442 A, JP 2007-518843 A. And the compounds described in Japanese Patent No. 4081112 are used. In the present embodiment, a monoalkoxyamine represented by the formula (I) is preferably used.

（式（Ｉ）中、Ｒ₁は炭素数１〜５個の直鎖又は分岐を有するアルキル基を表し、Ｒ₂は水素原子、炭素数１〜８個の直鎖又は分岐を有するアルキル基、炭素数６〜２０のアリール基、アルカリ金属イオン又はアンモニウムイオンを表す。）

(In the formula (I), R ₁ represents a linear or branched alkyl group having 1 to 5 carbon atoms, R ₂ represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, Represents an aryl group having 6 to 20 carbon atoms, an alkali metal ion or an ammonium ion.)

R ₁ represents a linear or branched alkyl group having 1 to 5 carbon atoms, preferably a linear alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.
R ₂ represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkali metal ion or an ammonium ion. Examples of the linear or branched alkyl group having 1 to 8 carbon atoms include a methyl group and an ethyl group, examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, and examples of the alkali metal ion include Li. ⁺ , Na ⁺ , K ^{+ and the} like, and ammonium ions include NH ₄ ⁺ , NBu ₄ ⁺ , HNBu ₃ ^{+ and the} like. Among these, in the present embodiment, R ² is preferably a hydrogen atom.

The NMRP method is preferably performed in a nitrogen atmosphere.
The reaction is preferably carried out in the presence or absence of a solvent selected from a solvent, preferably an alcohol such as ethanol, an aromatic solvent, a chlorinated solvent, an ether or a polar aprotic solvent. It is more preferred to react under
The reaction temperature is preferably in the range of 30 to 90 ° C, more preferably in the range of 50 to 90 ° C.

  The amount of nitroxide compound used is determined by the number average molecular weight at the end of the polymerization. Usually, the amount of the nitroxide compound to be used is determined stoichiometrically from the weight of the monomer to be used and the number average molecular weight.

  In this embodiment, the content of the block copolymer is preferably 50 to 99% by weight, and more preferably 70 to 95% by weight, based on 100% by weight of the electrostatic image developing toner. It is preferable for it to be within the above numerical value range because of excellent fixability in pressure or heat and pressure fixing.

<Resin having a Tg of 40 ° C. or higher>
In addition to the block copolymer, the toner for developing an electrostatic charge image of the exemplary embodiment preferably further contains a resin having a Tg of 40 ° C. or higher, and more preferably a resin having a Tg of 50 to 80 ° C. By adding a resin having a Tg of 40 ° C. or more to the electrostatic image developing toner, the mechanical stability of the toner in the electrophotographic process is further improved.
In the present embodiment, a mode in which the shell layer of the electrostatic charge image developing toner is formed of a resin having a Tg of 40 ° C. or more is preferable.

  Preferred examples of the resin include polycondensation resins such as polyester resins and polymers of ethylenically unsaturated compounds. In this case, the polycondensation resin is preferably an amorphous polyester resin or a crystalline polyester resin, and more preferably an amorphous polyester resin in order to improve the mechanical stability of the toner.

  The polyester resin is produced by performing polycondensation by a direct esterification reaction or a transesterification reaction using a polycondensable monomer such as a polyvalent carboxylic acid, a polyhydric alcohol, or a hydroxycarboxylic acid. In the case of polycondensation, it is preferable to use a polycondensation catalyst in combination in order to promote polycondensation.

  In the present embodiment, the polyvalent carboxylic acid includes aliphatic, alicyclic, and aromatic polyvalent carboxylic acids, their alkyl esters, acid anhydrides, and acid halides. The polyhydric alcohol includes polyhydric alcohols and ester compounds thereof. The alkyl ester of polyvalent carboxylic acid is preferably a lower alkyl ester. The said lower alkyl ester represents the alkyl ester whose carbon number of the alkoxy part of ester is 1-8. Specific examples include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, and isobutyl ester.

The polyvalent carboxylic acid that can be used in the present embodiment is a compound containing two or more carboxy groups in one molecule. Among these, dicarboxylic acid is a compound containing two carboxy groups in one molecule. For example, oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid , Decanedicarboxylic acid, undecanedicarboxylic acid, dodecenyl succinic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexanedicarboxylic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, 2,2-di Methylol butanoic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucous acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenyl Acetic acid, p-phenylenediacetic acid, m-phenol Range glycolic acid, p-phenylene diglycolic acid, o-phenylene diglycolic acid, diphenylacetic acid, diphenyl-p, p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene Examples include -2,6-dicarboxylic acid, anthracene dicarboxylic acid, dodecenyl succinic acid and the like.
Examples of the polyvalent carboxylic acid other than dicarboxylic acid include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid.
These polyvalent carboxylic acids may be used alone or in combination of two or more.

A polyhydric alcohol (polyol) is a compound containing two or more hydroxyl groups in one molecule. Among these, the diol is a compound containing two hydroxyl groups in one molecule, such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol. Bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, bisphenoxy alcohol fluorene (bisphenoxyethanol fluorene), and the like.
Examples of polyols other than diols include glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, and tetraethylol benzoguanamine.
These polyhydric alcohols (polyols) may be used alone or in combination of two or more.

In this embodiment, the ethylenically unsaturated compound is a compound having at least one ethylenically unsaturated bond, and may be a monomer having a hydrophilic group and an ethylenically unsaturated bond.
Examples of the hydrophilic group include polar groups, such as acidic polar groups such as carboxy group, sulfo group, and phosphonyl group: basic polar groups such as amino group, amide group, hydroxy group, cyano group, and formyl group. Examples include, but are not limited to, neutral polar groups.
Among these, acidic polar groups are preferably used for the electrostatic image developing toner of the present embodiment. The presence of the monomer having an acidic polar group and an ethylenically unsaturated bond in a specific range on the surface of the resin particles gives the resin particles cohesion, and the resin particles are converted into a toner. Sufficient chargeability is provided.
Examples of the acidic polar group preferably used include a carboxy group and a sulfo group. Examples of the monomer having an acidic polar group include an α, β-ethylenically unsaturated compound having a carboxy group and an α, β-ethylenically unsaturated compound having a sulfo group. Examples of the α, β-ethylenically unsaturated compound having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monomethyl maleate, monobutyl maleate, and maleic acid. A monooctyl ester is also mentioned. These monomers may be used individually by 1 type, and may use 2 or more types together.

The resin having a Tg of 40 ° C. or higher is preferably a random copolymer when it is a polymer of an ethylenically unsaturated compound.
Moreover, the resin which contains the ethylenically unsaturated compound which has a hydrophilic group as a monomer unit is preferable, and it is preferable to contain 0.1-10 mol% of ethylenically unsaturated compounds which have a hydrophilic group by copolymerization ratio. Within the above range, a resin having a Tg of 40 ° C. or more is preferable in the production process of the electrostatic charge image developing toner in the aqueous medium because the toner shell layer is easily formed.

  The polycondensation resin such as a polymer of an ethylenically unsaturated compound having a Tg of 40 ° C. or higher and a polyester resin is preferably 50% by weight or less, more preferably 5 to 20% by weight of the total binder resin contained in the toner. . Within the above range, toner durability in the developing machine is improved, and stable image quality characteristics can be obtained.

(2) Polyester Block Copolymer Having Crystalline Polyester Block and Amorphous Polyester Block The electrostatic charge image developing toner of the present embodiment is a crystalline polyester block (hereinafter referred to as “crystalline polyester resin”) as a block copolymer. It is also preferable to use a polyester block copolymer having a non-crystalline polyester block (hereinafter also referred to as “non-crystalline polyester resin”).

When a polyester block copolymer having a crystalline polyester resin and an amorphous polyester resin is formed, the copolymer exhibits a plastic behavior with respect to pressure. Shows fluidity. Further, it is considered that such plasticizing flow behavior is promoted under slight heating, and the resin fluidity necessary for fixing can be obtained even under a lower pressure.
In this embodiment, by using a polyester block copolymer having a crystalline polyester block and an amorphous polyester block, fluidity is imparted under a certain pressure or higher, and extremely solid at a pressure lower than that. Can be made to act. Therefore, the reliability in the development process, transfer process, cleaning process, etc., other than during pressing or heat-pressure fixing can be improved.
In particular, the toner for developing an electrostatic charge image according to the exemplary embodiment can be suitably used for fixing on a thick paper in which temperature fluctuation is likely to occur at the time of fixing because a plasticizing flow behavior is obtained by pressing. Up to now, high-speed fixing is difficult, and fixing to thick paper, which was difficult unless the fixing speed is reduced or a high heating temperature is set, is performed at the same fixing speed and temperature setting as fixing to thin paper. Is called.

The Tg of the crystalline polyester block is preferably 0 ° C. or lower, and more preferably −60 to −30 ° C. Moreover, it is preferable that Tg of the said amorphous polyester block is 50 degreeC or more, and it is more preferable that it is 50-90 degreeC.
The Tg of the crystalline polyester block being 0 ° C. or lower means that the glass transition point Tg of the crystalline polyester resin homopolymer used for the polyester block copolymer is 0 ° C. or lower. Moreover, Tg of an amorphous polyester block being 50 degreeC or more means that the glass transition point of the homopolymer of an amorphous polyester resin is 50 degreeC or more.
The Tg of the crystalline polyester affects the fixing performance depending on the pressure and / or temperature. When this value is 0 ° C. or less, the pressure and heat energy for fixing can be reduced. Further, the Tg of the amorphous polyester resin affects the stability of the toner in the developing machine against crushing and aggregation in the developing machine. When this value is 50 ° C. or higher, sufficient stability in the developing machine is obtained. It is done.

  In this case, the Tg is measured by the method defined in ASTM D3418-82 when a differential scanning calorimeter (DSC) is used and the temperature is increased from −80 ° C. to 150 ° C. at a rate of 10 ° C. per minute. Value.

In this embodiment, the electrostatic image developing toner includes a polyester block copolymer having at least one crystalline polyester block and at least one amorphous polyester block. In addition to the crystalline polyester block and the amorphous polyester block, other blocks may be included.
The polyester block copolymer preferably has a crystalline polyester block and an amorphous polyester block of 50 to 100% by weight, more preferably 80 to 100% by weight, more preferably than a crystalline polyester block and an amorphous polyester block. A polyester block copolymer is preferred.
The polyester block copolymer preferably has a crystalline polyester block having a Tg of 0 ° C. or lower and an amorphous polyester block having a Tg of 50 ° C. or higher. In addition to the crystalline polyester block having a Tg of 0 ° C. or less and the non-crystalline polyester block having a Tg of 50 ° C. or more, it may have other crystalline or non-crystalline polyester blocks. A polyester block copolymer consisting only of a crystalline polyester block having a Tg of 0 ° C. or less and an amorphous block having at least one Tg of 50 ° C. or more is preferable, and one Tg is 0 ° C. or less. It is more preferable that it is a diblock copolymer consisting only of a crystalline polyester block and an amorphous polyester block having one Tg of 50 ° C. or higher. Among these, a diblock copolymer composed only of a crystalline polyester block in which one Tg is 0 ° C. or less and an amorphous block in which one Tg is 50 ° C. or more is more preferable.

  The polyester block copolymer having a crystalline polyester block and an amorphous polyester block may be obtained by any production method. Specifically, a crystalline polyester resin and a non-crystalline polyester resin are mixed to produce a polymerized reaction, and the non-crystalline polyester resin-forming monomer is mixed with the crystalline polyester resin for polymerization. The method or the reverse method is used. Among these, a method in which a crystalline polyester resin and an amorphous polyester resin are mixed and a polyester block copolymer is obtained by a polymerization reaction is preferable.

  Each polyester block or polyester block copolymer is preferably obtained by polymerization at 150 ° C. or lower using sulfur acid as a catalyst. Thereby, each polyester block or polyester block copolymer can be obtained with low energy, which is preferable.

  The crystalline polyester block and non-crystalline polyester block used in this embodiment are, for example, aliphatic, alicyclic, aromatic polyvalent carboxylic acids or their alkyl esters, polyhydric alcohols or their ester compounds, A polycondensable monomer such as hydroxycarboxylic acid is used to carry out polycondensation by direct esterification reaction or transesterification reaction in an aqueous medium.

  “Crystallinity” as shown in the above “crystalline polyester block” means that in differential scanning calorimetry (DSC), it has a clear endothermic peak, not a step-like endothermic change. Means that the half-value width of the endothermic peak when measured at a heating rate of 10 ° C./min is within 15 ° C. On the other hand, a resin having a half-value width of an endothermic peak exceeding 15 ° C. or a resin having no clear endothermic peak means “non-crystalline” (amorphous).

The polyvalent carboxylic acid that can be used as the polycondensable monomer is a compound containing two or more carboxy groups in one molecule.
Among these, dicarboxylic acid is a compound containing two carboxy groups in one molecule. For example, oxalic acid, glutaric acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, Nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-carboxylic acid, malic acid, citric acid, hexahydroterephthalate Acid, malonic acid, pimelic acid, tartaric acid, mucoic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycol Acid, p-phenylene diglycolic acid, o-phenylene di- Recolic acid, diphenylacetic acid, diphenyl-p, p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, cyclohexanedicarboxylic acid Etc.
Examples of the polyvalent carboxylic acid other than dicarboxylic acid include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid.
Moreover, you may use what derived the carboxy group of these carboxylic acid into the acid anhydride, mixed acid anhydride, acid chloride, or ester.

The polyhydric alcohol used in the present embodiment is a compound containing two or more hydroxyl groups in one molecule. Among these, the diol is a compound containing two hydroxyl groups in one molecule. For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, butenediol, pentane. Examples include glycol, hexanediol, cyclohexanediol, cyclohexanedimethanol, octanediol, decanediol, dodecanediol, neopentyl glycol, polytetramethylene glycol, bisphenol A, bisphenol Z, and hydrogenated bisphenol A. The bisphenol A, bisphenol Z, hydrogenated bisphenol A, and the like may contain 1 to 6 moles of alkylene oxide such as ethylene oxide and propylene oxide added per molecule. A 3 molar adduct is preferably used.
Examples of polyhydric alcohols other than diols include glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, and tetraethylol benzoguanamine.
Since these polyhydric alcohols are hardly soluble or insoluble in the aqueous medium, the ester synthesis reaction proceeds in the monomer droplet in which the polyhydric alcohol is dispersed in the aqueous medium.

The hydroxycarboxylic acid used in the present embodiment is a compound having both a hydroxy group and a carboxy group in the molecule. Examples of the hydroxycarboxylic acid include aromatic hydroxycarboxylic acids and aliphatic hydroxycarboxylic acids, but it is preferable to use aliphatic hydroxycarboxylic acids.
Specific examples include hydroxyheptanoic acid, hydroxyoctanoic acid, hydroxydecanoic acid, hydroxyundecanoic acid, and lactic acid. Of these, lactic acid is preferably used.
In this embodiment, an amorphous polyester block or a crystalline polyester block can be easily obtained by a combination of these polycondensable monomers.

  As the polyvalent carboxylic acid used to obtain the crystalline polyester block, among the above polyvalent carboxylic acids, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, Sebacic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutamic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid Examples thereof include acids, acid anhydrides or acid chlorides thereof.

Examples of the polyhydric alcohol used to obtain the crystalline polyester block include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, , 4-butenediol, neopentyl glycol, 1,5-pentane glycol, 1,6-hexane glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, etc. Can be mentioned.
A crystalline polyester block obtained by ring-opening polymerization of a cyclic monomer such as caprolactone is also preferably used.

  Examples of such crystalline polyester blocks include polyesters obtained by reacting ethylene glycol and glutaric acid, 1,9-nonanediol and 1,10-decanedicarboxylic acid, or cyclohexanediol and adipic acid. Examples include polyesters obtained by reacting ethylene glycol, propanediol or 1,6-hexanediol with sebacic acid, and polyesters obtained by reacting ethylene glycol, propanediol or butanediol with succinic acid. . Among these, polyesters obtained by reacting succinic acid and propanediol, polyesters obtained by reacting glutaric acid and ethylene glycol, and polyesters obtained by reacting sebacic acid and propanediol are particularly preferable.

As the polyvalent carboxylic acid used to obtain the non-crystalline polyester block, among the above polyvalent carboxylic acids, dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, Nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylene diacetic acid, m-phenylene diglycolic acid, p-phenylene diglycolic acid, o-phenylene diglycolic acid, diphenyl diacetic acid, diphenyl-p, p'-dicarboxylic acid, Mention may be made of naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, cyclohexanedicarboxylic acid. Examples of the polyvalent carboxylic acid other than dicarboxylic acid include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid. Moreover, you may use what derived the carboxy group of these carboxylic acid into the acid anhydride, the acid chloride, or ester.
Among these, it is preferable to use terephthalic acid, its lower ester, diphenyldiacetic acid, cyclohexanedicarboxylic acid, or the like. The lower ester refers to an ester of an aliphatic alcohol having 1 to 8 carbon atoms.

The polyhydric alcohol used for obtaining the amorphous polyester in the present embodiment is, among the polyhydric alcohols, in particular, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A, cyclohexanedimethanol. Etc. are preferably used.
A polycondensate of hydroxycarboxylic acid is used as the non-crystalline polyester resin.

  The polycarboxylic acid and the polyhydric alcohol may be used alone or in combination of two or more, respectively, in order to produce one type of polycondensation resin. You may use each above. Moreover, when using hydroxycarboxylic acid for producing 1 type of polycondensation resin, 1 type may be used individually, 2 or more types may be used, and polyhydric carboxylic acid and polyhydric alcohol may be used together. .

  The weight ratio of the crystalline polyester block to the amorphous polyester block in the polyester block copolymer is preferably crystalline polyester block / non-crystalline polyester block = 1/20 to 20/1. 10/1 is more preferable. It is more preferable that the ratio is 1/9 to 5/5 because deterioration of toner charging property due to the crystalline polyester block can be suppressed. When the ratio of the crystalline polyester block and the non-crystalline polyester block is within the above range, the chargeability and mechanical strength as a polyester block copolymer when a toner is produced are sufficient, and the low-temperature fixability is excellent. Therefore, it is preferable. Furthermore, since it is excellent in the flow behavior under pressure, it is preferable.

  When a crystalline polyester block and an amorphous polyester block are mixed and a polyester block copolymer is obtained by a polymerization reaction, the crystalline polyester block preferably has a crystalline melting point of 40 to 150 ° C. More preferably, it is 50-120 degreeC, and it is especially preferable that it is 50-90 degreeC. It is preferable that the crystalline melting point of the crystalline polyester block to be used is in the above range since the resulting toner has good blocking resistance, good melt fluidity is obtained even at low temperatures, and good fixability.

  The melting point of the crystalline polyester block can be measured by, for example, “DSC-20” (manufactured by Seiko Instruments Inc.) according to differential scanning calorimetry (DSC). Specifically, about 10 mg of a sample is heated at a constant temperature. It can be obtained as the melting peak temperature of the input compensated differential scanning calorimetry shown in JIS K-7121: 87 when measuring at a rate of 10 ° C./min from room temperature to 150 ° C. at a rate (10 ° C./min). it can. In addition, although crystalline resin may show a some melting peak, in this embodiment, the largest peak is considered as melting | fusing point.

  When a crystalline polyester block and an amorphous polyester block are mixed and a polyester block copolymer is obtained by a polymerization reaction, the number average molecular weight of the mixed crystalline polyester block is 1,000 to 100,000. It is preferable that it is 1,500-30,000. The number average molecular weight of the non-crystalline polyester block to be mixed is preferably 1,000 to 100,000, more preferably 1,500 to 30,000.

  In this embodiment, the number average molecular weight of the polyester block copolymer is preferably 3,000 to 200,000, and more preferably 5,000 to 50,000. The polyester block copolymer that can be used in the present embodiment may be partially branched or cross-linked by the selection of the carboxylic acid valence of the monomer, the alcohol valence, the addition of a cross-linking agent, or the like. .

The value of the number average molecular weight Mn can be determined by various known methods, and there are some differences depending on the measurement method, but in the present embodiment, it is preferably determined by the following measurement method. That is, the number average molecular weight Mn is measured by gel permeation chromatography (GPC) under the conditions described below. At a temperature of 40 ° C., a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2 ml / min, and 3 mg of a tetrahydrofuran sample solution having a concentration of 0.2 g / 20 ml is injected as a sample weight for measurement. When measuring the molecular weight of a sample, select the measurement conditions that fall within the range in which the logarithm of the molecular weight of the calibration curve and the count number are linear, using several types of monodisperse polystyrene standard samples. .
The reliability of the measurement result is confirmed by the NBS706 polystyrene standard sample obtained under the above-described measurement conditions having a number average molecular weight Mn = 13.7 × 10 ⁴ .
As the GPC column to be used, any column may be adopted as long as it satisfies the above conditions. Specifically, for example, TSK-GEL, GMH (manufactured by Tosoh Corporation) or the like is used. In addition, a solvent and measurement temperature are not limited to the conditions described above, You may change to an appropriate condition.

The crystalline polyester block and the amorphous polyester block are produced by subjecting the polyhydric alcohol and polyvalent carboxylic acid to a polycondensation reaction according to a conventional method. This polycondensation reaction is carried out by a general polycondensation method such as bulk polymerization, emulsion polymerization, suspension polymerization, or other underwater polymerization, solution polymerization, interfacial polymerization, etc., but bulk polymerization is preferably used. Although the reaction is possible under atmospheric pressure, general conditions such as reduced pressure and nitrogen flow are used for the purpose of increasing the molecular weight of the resulting polyester molecule.
Specifically, the above polyhydric alcohol and polyvalent carboxylic acid, and if necessary, a catalyst are added, blended in a reaction vessel equipped with a thermometer, a stirrer, and a flow-down condenser, and an inert gas (nitrogen gas, etc.) Heating in the presence, continuously removing by-product low-molecular compounds out of the reaction system, stopping the reaction when it reaches the specified number average molecular weight, cooling, and obtaining the desired reactant Manufactured by.

In addition, it is preferable that at least one of the crystalline polyester block, the amorphous polyester block, and the polyester block copolymer is polymerized at 150 ° C. or lower in the presence of a sulfur acid catalyst.
A reaction temperature of 150 ° C. or lower is preferable because it can be produced with low energy. Among them, the step of forming the polyester block copolymer is obtained by adding a sulfur acid catalyst as a catalyst to the crystalline polyester block and the amorphous polyester block and heating at 150 ° C. or lower. Is preferred.

  Examples of the sulfur acid catalyst include benzene sulfonic acid, p-toluene sulfonic acid, dodecyl benzene sulfonic acid, isopropyl benzene sulfonic acid, camphor sulfonic acid and other alkyl benzene sulfonic acids, alkyl sulfonic acids, alkyl disulfonic acids, and alkylphenol sulfonic acids. , Alkyl naphthalene sulfonic acid, alkyl tetralin sulfonic acid, alkyl allyl sulfonic acid, petroleum sulfonic acid, alkyl benzimidazole sulfonic acid, higher alcohol ether sulfonic acid, alkyl diphenyl sulfonic acid, monobutyl phenyl phenol sulfuric acid, dibutyl phenyl phenol sulfuric acid, dodecyl sulfuric acid Higher fatty acid sulfate, higher alcohol sulfate, higher alcohol ether sulfate, higher fatty acid amide alkylol sulfate Steal, higher fatty acid amide alkylated sulfuric acid ester, naphthenyl alcohol sulfuric acid, sulfated fat, sulfosuccinic acid ester, sulfonated higher fatty acid, resin acid alcohol sulfuric acid, and all these salt compounds can be used, but are not limited thereto. . Moreover, these catalysts may have a functional group in the structure. A plurality of these catalysts may be combined as necessary. As the sulfur acid catalyst preferably used, alkylbenzenesulfonic acid is exemplified, and among these, dodecylbenzenesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid and the like are preferable.

  Among these, as the sulfur acid catalyst, those having the structure of the following formula (i) or formula (ii) are particularly preferable.

式（ｉ）中、Ｒ¹は炭素数８以上のアルキル基を表す。式（ii）中、Ｒ²は炭素数８以上のアルキル基又は炭素数８以上のアルコキシ基を表す。

In formula (i), R ¹ represents an alkyl group having 8 or more carbon atoms. In formula (ii), R ² represents an alkyl group having 8 or more carbon atoms or an alkoxy group having 8 or more carbon atoms.

In formula (i), R ¹ preferably has 8 to 20 carbon atoms, and more preferably has 8 to 16 carbon atoms. R ¹ may be a branched alkyl chain or a linear alkyl chain, but is preferably a linear alkyl chain.

In formula (ii), R ² preferably has 8 to 20 carbon atoms, and more preferably 8 to 16 carbon atoms. When R ² is an alkyl group, it may be a branched alkyl chain or a linear alkyl chain, but it is more preferably a linear alkyl chain. When R ² is an alkoxy group, it may be an alkoxy group having a branched alkyl chain or an alkoxy group having a linear alkyl group, but may be an alkoxy group having a linear alkyl group. More preferred.

  Other commonly used polycondensation catalysts can be used together with the above catalyst. Specific examples include a metal catalyst, a hydrolase type catalyst, a basic catalyst, and a Bronsted acid catalyst other than sulfur acid.

Examples of the metal catalyst include, but are not limited to, the following. For example, an organic tin compound, an organic titanium compound, an organic tin halide compound, and a rare earth metal catalyst can be used.
Specific examples of the rare earth-containing catalyst include scandium (Sc), yttrium (Y), and lanthanoid elements such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium. (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc. are effective. is there. Of these, alkylbenzene sulfonates, alkyl sulfate esters, and those having a triflate structure are particularly effective. Examples of the triflate include X (OSO ₂ CF ₃ ) _{3 in} the structural formula. Here, X is a rare earth element, and among these, X is preferably scandium (Sc), yttrium (Y), ytterbium (Yb), samarium (Sm), or the like.
The lanthanoid triflate is described in detail in Journal of Synthetic Organic Chemistry, Vol. 53, No. 5, p44-54.

The hydrolase type catalyst is not particularly limited as long as it catalyzes an ester synthesis reaction. Examples of the hydrolase include EC (enzyme number) 3.1 group (Maruo, Lipoprotein lipase, etc.) such as carboxyesterase, lipase, phospholipase, acetylesterase, pectinesterase, cholesterol esterase, tannase, monoacylglycerol lipase, lactonase and lipoprotein lipase. Hydrolysis enzymes and epoxides classified into EC 3.2 groups that act on glycosyl compounds such as esterases, glucosidases, galactosidases, glucuronidases, and xylosidases classified in the “Enzyme Handbook” supervised by Tamiya (Asakura Shoten, (1982), etc.) Classify into EC3.4 group that acts on peptide bonds such as hydrolase, aminopeptidase, chymotrypsin, trypsin, plasmin, subtilisin etc. Hydrolase, hydrolases such classified into EC3.7 group such as furo retinoic hydrolase and the like.
Among the above esterases, enzymes that hydrolyze glycerol esters to liberate fatty acids are called lipases, but lipases are highly stable in organic solvents, catalyze ester synthesis reactions in high yields, and are available at a lower price. There are advantages such as what you can do. Therefore, also in this embodiment, it is preferable to use lipase in terms of yield and cost.
Lipases of various origins can be used, but preferable examples include Pseudomonas genus, Alcaligenes genus, Achromobacter genus, Candida genus, Aspergillus genus, Rhizopus Examples include lipases obtained from microorganisms such as (Rhizopus) genus and Mucor genus, lipases obtained from plant seeds, lipases obtained from animal tissues, pancreatin, and steapsin. Among these, it is preferable to use lipases derived from microorganisms of the genus Pseudomonas, Candida, and Aspergillus.

Examples of the basic catalyst include, but are not limited to, general organic basic compounds, nitrogen-containing basic compounds, and tetraalkyl or arylphosphonium hydroxides such as tetrabutylphosphonium hydroxide. Examples of the organic base compound include ammonium hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, and examples of the nitrogen-containing basic compound include amines such as triethylamine and dibenzylmethylamine, pyridine, methylpyridine, methoxypyridine, Quinolin, imidazole, alkali metals such as sodium, potassium, lithium, cesium, and alkaline earth metals such as calcium, magnesium, barium, hydroxides, hydrides, amides, alkalis, alkaline earth metals and acids Salts such as carbonates, phosphates, borates, carboxylates and salts with phenolic hydroxyl groups.
Moreover, a compound with an alcoholic hydroxyl group, a chelate compound with acetylacetone, and the like can be mentioned, but the invention is not limited thereto.

  Examples of Bronsted acid catalysts other than sulfur acids include, but are not limited to, various fatty acids, higher alkyl phosphate esters, resin acids, naphthenic acids, and niobic acids.

  The total amount of catalyst added is preferably 0.01 to 10% by weight, more preferably 0.01 to 8% by weight, based on the polycondensation component. A catalyst may be used individually by 1 type and may use 2 or more types together.

The toner for developing an electrostatic charge image of this embodiment may contain a polymer of an ethylenically unsaturated compound in addition to the polyester block copolymer.
The ethylenically unsaturated compound is a monomer having at least one ethylenically unsaturated bond. Examples of the group having an ethylenically unsaturated bond include a vinyl group, a (meth) acryloyloxy group, a styryl group, ( Preferred examples include a (meth) acrylamide group and a vinyl ether group (“(meth) acryloxy group” and the like mean “acryloxy group and / or methacryloxy group”, and the same shall apply hereinafter). ).
Further, monomers having an ethylenically unsaturated bond include aromatic vinyl monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers. Examples include a monomer, a diolefin monomer, and a halogenated olefin monomer.

Examples of the aromatic vinyl monomer include styrene and its derivatives. The derivative of styrene here means styrene having at least one substituent on the benzene ring, and as the substituent, a linear or branched alkyl group having 1 to 15 carbon atoms, or 1 to 4 carbon atoms. Alkyloxy groups, aryl groups having 6 to 12 carbon atoms, halogen atoms such as fluorine, chlorine and iodine.
Examples of styrene and derivatives thereof include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, and pn-. Butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl Examples thereof include styrene such as styrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Cyclohexyl (meth) acrylate, phenyl (meth) acrylate, ethyl β-hydroxy- (meth) acrylate, γ-amino-propyl (meth) acrylate, stearyl (meth) acrylate, dimethyl (meth) acrylate Examples include aminoethyl and diethylaminoethyl (meth) acrylate.

Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.
Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.
Examples of the halogenated olefin monomer include vinyl chloride, vinylidene chloride, vinyl bromide and the like. The ethylenically unsaturated compounds that can be used in the present embodiment are not limited to these, and these ethylenically unsaturated compounds may be used alone or in combination of two or more.

  In this embodiment, the polymer of the ethylenically unsaturated compound is preferably a copolymer obtained by copolymerizing one or more of the ethylenically unsaturated compounds, and is a copolymer. In particular, a random copolymer is preferable.

In the present embodiment, the ethylenically unsaturated compound is an aromatic vinyl monomer as a main component in view of its charging characteristics, image quality characteristics, etc., when considering application to an electrostatic charge image developing toner. It is preferable to use styrene, and it is more preferable to use styrene or a derivative thereof.
Here, the main component means that styrene and derivatives thereof are 50% by weight or more of all ethylenically unsaturated compounds. When the content of styrene and its derivative is 50% by weight or more, the charging characteristics (charge amount, charge speed) are good when used as a toner.

The glass transition point Tg of the polymer of the ethylenically unsaturated compound is preferably 40 ° C. or higher, and preferably 50 to 100 ° C. Within the above numerical range, toner storage stability is excellent, and toner destruction in the developing machine is suppressed.
The number average molecular weight of the ethylenically unsaturated compound polymer is preferably 5,000 to 50,000, more preferably 8,000 to 30,000. It is preferable that the value is within the above numerical value range because the toner system strength, fixability, and image strength after fixing are good.

Furthermore, the addition amount of the polymer of the ethylenically unsaturated compound is preferably 5 to 50% by weight, more preferably 8 to 40% by weight, based on the total weight of the binder resin constituting the toner. 8-30 wt% is more preferable.
When the value is within the above range, the toner has excellent stability in the developing machine, and excellent image quality characteristics can be obtained without causing toner crushing or aggregation. Energy fixing characteristics can be obtained.

In the present embodiment, the ethylenically unsaturated compound may be a monomer having a hydrophilic group.
Examples of hydrophilic groups include polar groups such as acidic polar groups such as carboxy group, sulfo group and phosphonyl group, basic polar groups such as amino group, amide group, hydroxy group, cyano group and formyl group. Neutral polar groups and the like can be mentioned, but are not limited thereto.
Among these, acidic polar groups are particularly preferably used for the toner. The presence of a certain amount of this monomer having an acidic polar group and an ethylenically unsaturated bond on the surface of the resin particle imparts cohesiveness to the resin particle, facilitates the formation of a resin particle into a toner, and is sufficient for a toner. Can be easily charged.
Examples of the acidic polar group preferably used include a carboxy group and a sulfo group. Examples of the monomer having an acidic polar group include an α, β-ethylenically unsaturated compound having a carboxy group and an α, β-ethylenically unsaturated compound having a sulfo group. Examples of the α, β-ethylenically unsaturated compound having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monomethyl maleate, monobutyl maleate, and maleic acid. And acid monooctyl ester.
These monomers may be used individually by 1 type, and may use 2 or more types together.

  The polymer which contains the ethylenically unsaturated compound which has a hydrophilic group as a monomer unit is preferable, and it is preferable to contain 0.1-10 mol% of ethylenically unsaturated compounds which have a hydrophilic group by copolymerization ratio. It is preferable that the value is within the above-mentioned range since the cohesiveness in toner formation is good.

  The binder resin may contain other resins such as an amorphous polyester resin in addition to the polyester block copolymer and the polymer of the ethylenically unsaturated compound. The content of the polyester block copolymer and the polymer of the ethylenically unsaturated compound is preferably 50 to 100% by weight, more preferably 80 to 100% by weight of the total binder resin. It is preferable for it to be within the above numerical value range since the fixing property under pressure is good.

The electrostatic image developing toner of the present embodiment may be a multi-layered particle having an inner shell and at least one outer shell covering the inner shell. In such an embodiment, the binder resin includes both the resin contained in the inner shell and the outer shell.
In the present embodiment, the inner shell is preferably a particle containing at least the polyester block copolymer as a binder resin, and is a particle containing a colorant, a release agent and the like in addition to the binder resin. Is more preferable.
The outer shell is preferably a binder resin layer that covers the surface of the inner shell, and more preferably a binder resin layer that does not contain the polyester block copolymer from the viewpoint of mechanical strength. When increasing the mechanical strength of the toner, it is preferable that the binder resin used as the outer shell is a resin of the ethylenically unsaturated compound, a resin such as an amorphous polyester resin, or a combination of resins. .

(Resin particles having a core-shell structure)
The toner used in the exemplary embodiment may be an electrostatic charge image developing toner obtained by aggregating resin particles having a core-shell structure (hereinafter also referred to as core-shell particles).
The method for confirming that there are a plurality of core-shell resin particles contained in the toner is not particularly limited, and the contrast is clarified by a method of observing the cross section of the toner with a transmission electron microscope or by staining. And a method of observing the cross section with a scanning electron microscope. In some cases, it is clear that there are two or more core-shell particles contained in the toner from the ratio of the toner particle diameter to the core-shell particles at the time of manufacture, the amount of core-shell particles used, the production method, and the like.

  Either the resin constituting the core or the resin constituting the shell of the core-shell particles may be a high Tg resin. In this embodiment, the higher glass transition temperature of the core or shell is also referred to as a high Tg phase, and the lower one is also referred to as a low Tg phase.

  The glass transition temperature (Tg) of the high Tg phase is preferably 45 to 80 ° C, and more preferably 50 to 70 ° C. When the glass transition temperature of the high Tg phase is 45 ° C. or higher, the toner storage property is excellent, and filming on the photoreceptor is difficult to occur during caking or in continuous printing during transportation or in a printer. It is preferable because image quality defects are less likely to occur. Further, when the glass transition temperature of the high Tg phase is 80 ° C. or less, the fixing temperature at the time of fixing (particularly at the time of fixing thick paper) is appropriate, and damage to the recording medium such as paper curl is unlikely to occur.

  The resin particles having a core-shell structure preferably have a difference between the glass transition temperature of the resin constituting the core and the glass transition temperature of the resin constituting the shell of 20 ° C. or higher, and more preferably 30 ° C. or higher. When the glass transition temperature difference between the high Tg phase and the low Tg phase is 20 ° C. or more, sufficient pressure plasticization behavior is obtained, and paper curling is suppressed.

  Examples of the resin particles having a core-shell structure that can be used in the present embodiment include resin particles produced using the raw materials and production methods described in JP-A-2007-310064 and JP-A-2007-322953. .

  In this embodiment, the toner preferably contains a block copolymer as a binder resin.

(Electrostatic image developing toner and method for producing the same)
In this embodiment, a method for producing a toner for developing an electrostatic charge image includes aggregating the resin particles and the release agent particles in a dispersion containing the resin particles containing the balloplastic and the release agent particles to form aggregated particles. It is preferable to include a step of obtaining (hereinafter, also referred to as “aggregation step”) and a step of heating and coalescing the aggregated particles (hereinafter also referred to as “fusion coalescence step”).

  In the method for producing a toner for developing an electrostatic charge image, particles containing colorant particles (a colorant is added in advance to a resin in a polymerization step or the like), if necessary, to a dispersion containing at least resin particles and release agent particles. In this case, colored particles themselves), other resin particles, or dispersions thereof may be added. In the method for producing a toner for developing an electrostatic image, the resin particles, release agent particles and other added particles in the dispersion are aggregated (aggregated) using a known aggregation method. Thus, the toner particle size and particle size distribution can be adjusted. Specifically, the resin particle dispersion and the release agent particle dispersion are mixed with the colorant particle dispersion and the like, and further, an aggregating agent is added to form heteroaggregation to form aggregated particles having a toner diameter. The toner for developing an electrostatic image can be obtained by heating the resin particles to a temperature higher than the glass transition temperature or higher than the melting point, fusing and aggregating the aggregated particles, washing and drying. In this manufacturing method, the toner shape is controlled from an indeterminate shape to a spherical shape by selecting a heating temperature condition.

In order to obtain a resin particle dispersion, any method of dispersing a block copolymer in an aqueous medium may be used, and for example, emulsification or dispersion is performed using mechanical shear or ultrasonic waves.
The resin particle dispersion may contain additives such as a surfactant, a polymer dispersant, and an inorganic dispersant. It is also possible to add a surfactant, a polymer dispersant, an inorganic dispersant and the like to the aqueous medium as necessary during the above emulsification dispersion.

In the present embodiment, examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols such as ethanol and methanol. Among these, ethanol and water are preferable, and water such as distilled water and ion exchange water is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.
The aqueous medium may contain a water-miscible organic solvent. Examples of the water-miscible organic solvent include acetone and acetic acid.

Examples of the surfactant that can be used in this embodiment include anionic surfactants such as sulfate ester salts, sulfonate salts, and phosphate ester systems; and cationic interfaces such as amine salt types and quaternary ammonium salt types. Activators: Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like. Among these, anionic surfactants and cationic surfactants are preferable.
The said surfactant may be used individually by 1 type, and may use 2 or more types together. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant.

  Anionic surfactants include sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium arylalkylpolyethersulfonate, 3,3′-disulfonediphenylurea-4,4′-diazo-bis-amino-8-naphthol Sodium 6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2 ′, 5,5′-tetramethyl-triphenylmethane-4,4′-diazo-bis-β-naphthol-6-sulfone Sodium sulfate, sodium dialkylsulfosuccinate, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate, Sodium prong, potassium stearate, and the like calcium oleate.

  Examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

  Nonionic surfactants include polyethylene oxide, polypropylene oxide, combinations of polypropylene oxide and polyethylene oxide, esters of polyethylene glycol and higher fatty acids, alkylphenol polyethylene oxide, esters of higher fatty acids and polyethylene glycol, higher fatty acids and polypropylene oxide. Examples thereof include esters and sorbitan esters.

Examples of the polymer dispersant include sodium polycarboxylate and polyvinyl alcohol, and examples of the inorganic dispersant include calcium carbonate. However, these do not limit the present embodiment.
Furthermore, in order to prevent the Ostwald Rippening phenomenon of monomer emulsion particles in an aqueous medium, usually, higher alcohols typified by heptanol and octanol, and higher aliphatic hydrocarbons typified by hexadecane are used as stabilizing aids. May be blended.

  In the aggregation step of the present embodiment, the resin particle dispersion other than the block copolymer resin particle dispersion and the block copolymer resin particle dispersion are mixed, and the steps after aggregation may be performed. At that time, after the block copolymer resin particle dispersion is agglomerated in advance and the first aggregated particles are formed, a block copolymer resin particle dispersion or another resin particle dispersion is further added to the surface of the first particles. The shell layer may be formed to form a multi-layered particle. Of course, multilayer particles may be produced in the reverse order of the above example.

  Further, for example, in the aggregation step, the resin particle dispersion containing the block copolymer and the colorant particle dispersion are aggregated in advance, and after the formation of the first aggregated particles, the resin particle dispersion containing the block copolymer or another The resin particle dispersion may be added to form a second shell layer on the surface of the first particles. In this illustration, the colorant dispersion is separately prepared, but naturally the colorant may be blended in advance with the block copolymer in the present embodiment.

  As the flocculant, in addition to the surfactant, inorganic salts and divalent or higher metal salts are preferably used. In particular, when a metal salt is used, it is preferable in characteristics such as cohesion control and toner chargeability. The metal salt compound used for aggregation is obtained by dissolving a general inorganic metal compound or a polymer thereof in a resin particle dispersion, but the metal elements constituting the inorganic metal salt are a periodic table (long period table). 2A, 3A, 4A, 5A, 6A, 7A, 8, 1B, 2B, 3B (groups 2 to 13) having a valence of 2 or more, and in the form of ions in the resin particle aggregation system Any material that dissolves may be used. Specific examples of preferred inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, calcium polysulfide. And inorganic metal salt polymers. Among these, an aluminum salt and a polymer thereof are particularly preferable. In general, in order to obtain a sharper particle size distribution, it is preferable that the valence of the inorganic metal salt is bivalent rather than monovalent, and trivalent or more valent than bivalent. A type of inorganic metal salt polymer is more suitable.

  Further, in this embodiment, in addition to the block copolymer resin particle dispersion, an addition polymerization resin particle dispersion prepared by using conventionally known emulsion polymerization or the like is used in combination. The median diameter of the resin particles in the addition polymerization resin particle dispersion used in the present embodiment is preferably 0.02 to 2.0 μm as in the resin particle dispersion of the present embodiment.

  Examples of addition polymerization monomers for preparing these addition polymerization resin particle dispersions include styrenes such as styrene and parachlorostyrene, vinyl naphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, acetic acid. Vinyl esters such as vinyl, vinyl propionate, vinyl benzoate, vinyl butyrate, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, acrylic acid 2 -Methylene aliphatic carboxylic acid esters such as chloroethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide such as vinyl methyl ether, vinyl ethyl A Monomers having an N-containing polar group, such as N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. Further, homopolymers and copolymers of vinyl monomers such as vinyl carboxylic acids such as acrylic acid, cinnamic acid and carboxyethyl acrylate, and various waxes are also used.

  In the case of an addition polymerization monomer, emulsion polymerization is carried out using an ionic surfactant or the like to produce a resin particle dispersion. In the case of other resins, a solvent that is oily and has a relatively low solubility in water. If the resin dissolves in the solvent, dissolve the resin in these solvents, disperse the particles in an aqueous medium with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte, and then heat or reduce the solvent. The resin particle dispersion can be obtained by evaporating.

  Further, a polymerization initiator or a chain transfer agent may be used during the polymerization of the addition polymerization monomer. As the polymerization initiator, a known polymerization initiator can be used, and specifically, a radical polymerization initiator described in paragraph 0037 of JP-A-2007-310064 is preferably used.

  There is no restriction | limiting in particular as a chain transfer agent, Specifically, what has the covalent bond of a carbon atom and a sulfur atom is preferable, For example, thiols are mentioned preferably.

  In the present embodiment, if necessary, one or more known additives are blended in combination within a range that does not affect the result of the present embodiment. For example, flame retardants, flame retardant aids, brighteners, waterproofing agents, water repellents, magnetic materials, inorganic fillers (surface modifiers), mold release agents, antioxidants, plasticizers, surfactants, dispersants Lubricants, fillers, extender pigments, binders, charge control agents and the like. These additives are blended in any manufacturing of the coating agent. In preparing the toner in this embodiment, when polymerized resin particles are polymerized in an aqueous medium, components necessary for a normal toner such as a fixing agent such as a colorant and wax, and other charging assistants are previously added to the aqueous medium. In some cases, it is preliminarily mixed therein and blended into the polymer resin particles together with the polymerization.

Examples of the colorant that can be used in the present embodiment include the following.
Examples of black pigments include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.
Examples of yellow pigments include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, Hansa yellow, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, and permanent yellow NCG.
Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, benzidine orange G, indanthrene brilliant orange RK, indanthrene brilliant orange GK and the like.
Red pigments include Bengala, cadmium red, red lead, mercury sulfide, watch young red, permanent red 4R, risor red, brilliantamine 3B, brilliantamine 6B, dapon oil red, pyrazolone red, rhodamine B rake, lake red C , Rose bengal, oxin red, alizarin lake and the like.
Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, induslen blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate and so on.
Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.
Examples of the green pigment include chromium oxide, chrome green, pigment green, malachite green lake, final yellow green G, and the like.
Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.
Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.
Examples of the dye include various dyes such as basic, acidic, dispersed, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

These colorants are used alone or in combination. These colorants can be dispersed by any method, for example, a ball-type mill having a rotating shear type homogenizer, a media mill such as a sand mill or an attritor, a high-pressure counter collision type disperser, or a general dispersion such as a dyno mill. By using the method, a dispersion of colorant particles is prepared.
These colorants are dispersed in an aqueous system by a homogenizer using a polar surfactant, and may be added together with other particle components in a mixed solvent at once, or divided into multiple stages. It may be added.

The colorant of this embodiment is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner. The colorant is added in the range of 4 to 15% by weight with respect to the total weight of the toner constituent solids.
When using a magnetic material as the black colorant, 12 to 240% by weight is added unlike other colorants.
The blending amount of the colorant is a preferable amount in order to ensure color developability at the time of fixing.
Moreover, OHP transparency and color developability are ensured by setting the central diameter (median diameter) of the colorant particles in the toner to 100 to 330 nm.
The center diameter of the colorant particles is measured, for example, with a laser diffraction particle size distribution measuring apparatus (LA-920, manufactured by Horiba, Ltd.).

Specific examples of the release agent used in the present embodiment include, for example, various ester waxes, low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, silicones that exhibit a softening point by heating, oleic acid amide, erucic acid amide, Fatty acid amides such as ricinoleic acid amide and stearic acid amide, carnauba wax, rice wax, candelilla wax, plant wax such as tree wax and jojoba oil, animal wax such as beeswax, montan wax , Mineral-based and petroleum-based waxes such as ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and modified products thereof.
These waxes are hardly dissolved in a solvent such as toluene at room temperature or very little even if dissolved.
These waxes are dispersed in water together with ionic surfactants, polymer electrolytes such as polymer acids and polymer bases, heated above the melting point, and have strong shearing ability and pressure discharge type dispersers (Gorin homogenizer, manufactured by Gorin Co., Ltd.) is dispersed in the form of particles to produce a dispersion of particles of 1 μm or less.
These release agents are preferably added in the range of 5 to 25% by weight with respect to the total weight of the toner constituent solids, in order to ensure the peelability of the fixed image in the oilless fixing system.
The particle size of the obtained release agent particle dispersion is measured, for example, with a laser diffraction particle size distribution analyzer (LA-920, manufactured by Horiba, Ltd.). In addition, when using a release agent, after the resin particles, colorant particles and release agent particles are agglomerated, it is possible to add a resin particle dispersion to adhere the resin particles to the surface of the agglomerated particles. From the viewpoint of securing the property.

Specifically, a substance that is magnetized in a magnetic field is used as the magnetic material, but a ferromagnetic powder such as iron, cobalt, or nickel, or a compound such as ferrite or magnetite is used. In the present embodiment, when toner is obtained in an aqueous medium, it is necessary to pay attention to the water phase transferability of the magnetic material. Preferably, the surface of the magnetic material is modified in advance and subjected to, for example, a hydrophobic treatment. Is preferred.
As the charge control agent, various commonly used charge control agents such as quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments can be used. In addition, a material that is difficult to dissolve in water is preferable from the viewpoint of controlling the ionic strength that affects the stability at a time and reducing wastewater contamination.

  Examples of surfactants used for polymerization, pigment dispersion, resin particle production and dispersion, mold release agent dispersion, aggregation, or stabilization thereof are sulfate ester, sulfonate, phosphate, soap Anionic surfactants such as amine salts, cationic surfactants such as amine salt type and quaternary ammonium salt type, and nonionic surfactants such as polyethylene glycol type, alkylphenol ethylene oxide adduct type, polyhydric alcohol type It is also effective to use a general means such as a rotary shear type homogenizer, a ball mill having a media, a sand mill, or a dyno mill.

  Examples of flame retardants and flame retardant aids include, but are not limited to, bromine flame retardants that have already been widely used, antimony trioxide, magnesium hydroxide, aluminum hydroxide, and ammonium polyphosphate.

  After completing the coalescing and coalescing process of the aggregated particles, the desired toner particles are obtained through any washing process, solid-liquid separation process, and drying process. It is preferable to wash. Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

Furthermore, the toner of the present embodiment is preferably used by mixing inorganic particles or adding them to the resin particle surface for the purpose of imparting fluidity or improving cleaning properties.
The inorganic particles that can be used in the present embodiment are particles having a primary particle size of preferably 5 nm to 2 μm, more preferably 5 nm to 500 nm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion mixed with the toner is 0.01 to 5% by weight, preferably 0.01 to 2.0% by weight.

  Examples of such inorganic particles include silica powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, Examples thereof include chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Silica powder is particularly preferable.

The silica powder here is a powder having a Si—O—Si bond, and includes both those produced by a dry method and a wet method. In addition to anhydrous silicon dioxide, any of aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate and the like may be used, but those containing SiO _{2 in an amount} of 85% by weight or more are preferable.

  Specific examples of these silica powders include various commercially available silicas, and those having a hydrophobic group on the surface are preferred, such as AEROSIL R-972, R-974, R-805, R-812 (above, Nippon Aerosil). Co., Ltd.), Tarax 500 (manufactured by Tarco) and the like. In addition, silica powder treated with a silane coupling agent, a titanium coupling agent, silicon oil, silicon oil having an amine in the side chain, or the like is used.

The cumulative volume average particle diameter D ₅₀ of the toner used in this embodiment is suitably in the range of 3.0 to 9.0 μm. It is preferable that D ₅₀ is 3.0 μm or more because the adhesive force is appropriate and the developability is excellent. Further, when D ₅₀ is less than 9.0 .mu.m, preferably for the resolution of the image is good.
Further, the volume average particle size distribution index GSDv of the toner used in this embodiment is preferably 1.30 or less. A GSDv of 1.30 or less is preferable because the resolution is good and image defects such as toner scattering and fogging hardly occur.
The cumulative volume average particle diameter D ₅₀ and average particle size distribution index GSDv of the toner used in the present embodiment are, for example, Coulter Counter TA-II (manufactured by Beckman Coulter, Inc.), Multisizer II (manufactured by Beckman Coulter, Inc.). ) For the particle size range (channel) divided on the basis of the particle size distribution measured with a measuring instrument such as _16v, number D _16P, 50% cumulative become a particle size volume D _50v, number D _50P, the volume particle size at a cumulative 84% D _84v, defined as the number D _84P. Using these, the volume average particle size distribution index (GSDv) is calculated as (D _84v / D _16v ) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D _84P / D _16P ) ^1/2 .

The toner shape factor SF1 of the present embodiment is preferably in the range of 100 to 140, and more preferably in the range of 110 to 135, from the viewpoint of image formability. The shape factor SF1 of the present embodiment can be quantified mainly by analyzing a microscope image or a scanning electron microscope image with an image analyzer, and is obtained by the following method, for example. First, an optical microscope image of the toner spread on the slide glass is taken into a Luzex image analyzer through a video camera, and the absolute maximum length of toner particles and the projected area of toner particles are measured for 50 or more toners. It can obtain | require by the type | formula of this.
SF1 = {(ML) ² / A} × (π / 4) × 100
In the formula, ML represents the maximum length of toner particles, and A represents the projected area of the particles.

  Hereinafter, the present embodiment will be described in more detail with reference to examples. However, the present embodiment is not limited to the following examples.

(Synthesis of block copolymer (1))
A synthesis example of a blocked vinyl resin will be described.
150 parts of styrene monomer (St) and 7 parts of 2-ethylhexyl acrylate, MBPAP (MBPAP: 2-methyl-2- [N- (tert-butyl)- 14.8 parts of N- (1-diethoxyphosphoryl-2,2-dimethylpropyl) -aminoxy] -propionic acid) are added and mixed well at 80 ° C. under a nitrogen stream, the temperature is raised to 110 ° C. and styrene is added. And 2-ethylhexyl acrylate were polymerized. The molecular weight was measured with GPC as needed, and when the number average molecular weight of styrene reached 10,000, the amount of residual styrene was measured by the weight loss method and the polymerization rate (conversion rate) was determined to be 99.5%. there were. Thereafter, 210 parts of stearyl acrylate (StA) and 20 parts of 2-ethylhexyl acrylate were added, and the polymerization was continued at 130 ° C. to carry out chain extension with stearyl acrylate and 2-ethylhexyl acrylate.
When the number average molecular weight of the stearyl acrylate block unit was 40,000, and the total of the styrene chain polymerized first was 60,000, the mixture was cooled to room temperature. The polymer is dissolved in 225 parts of THF (THF: tetrahydrofuran), taken out and added dropwise to methanol to reprecipitate the block polymer, and then the precipitate is filtered, washed repeatedly with methanol, and then vacuum lyophilized. A block copolymer resin (1) of styrene and stearyl acrylate was obtained.
The glass transition temperature of the block copolymer resin (1) was 28 ° C. Moreover, T (1 MPa) -T (10 MPa) in the flow tester viscosity measurement was 32 ° C.

(Preparation of resin particle dispersion (1))
To 400 parts of the block copolymer resin (1), 8.0 parts of sorbitan sesquiolate and 120 parts of methyl ethyl ketone (MEK) in which 0.8 parts of sodium dodecylbenzenesulfonate are dissolved are added, a reflux condenser, a stirrer, After being charged into a reactor equipped with an ion-exchange water dropping device and a heating device, the mixture was well mixed at 65 ° C. Then, after heat-mixing at 65 degreeC for 1 hour, 1,000 parts ion-exchange water was dripped at the speed | rate of 1 part / min, and the phase inversion emulsification of the block copolymer resin (1) was performed. Further, the phase-inverted emulsion was cooled and MEK was removed from the emulsion under reduced pressure at 60 ° C. using an evaporator to obtain a resin particle dispersion (1).
The volume average particle diameter of the resin particles in the obtained resin particle dispersion (1) was 210 nm, and the solid content concentration was 40%.

(Preparation of colorant particle dispersion (C1))
Cyan pigment 50 parts by weight (manufactured by Dainichi Seika Kogyo Co., Ltd., copper phthalocyanine CI Pigment Blue 15: 3)
Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) 5 parts by weight Ion-exchanged water 200 parts by weight The above components are mixed and dissolved, and dispersed for 5 minutes with a homogenizer (IKA Corporation, Ultra Tarrax). Then, the dispersion was carried out for 10 minutes by an ultrasonic bath to obtain a cyan colorant particle dispersion having a center diameter of 190 nm and a solid content of 21.5%.

(Preparation of release agent particle dispersion (W1))
Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) 2 parts by weight Ion-exchanged water 800 parts by weight Carnauba wax 215 parts by weight And then emulsified at 100 ° C. using a gorin homogenizer. As a result, a release agent particle dispersion having a particle central diameter of 170 nm, a melting point of 83 ° C., and a solid content of 21.5% was obtained.

(Preparation of toner particles (1))
Next, toner preparation will be described. The formulation is as follows.
Resin particle dispersion (1) 272 parts (54.4 parts resin)
Colorant particle dispersion (C1) 40 parts (8.6 parts of pigment)
80 parts of release agent particle dispersion (W1) (17.2 parts of release agent)
Polyaluminum chloride 0.15 parts Ion-exchanged water 300 parts In accordance with the above composition, the components were thoroughly mixed and dispersed in a round stainless steel flask with a homogenizer (IKA, Ultra Turrax T50), and then heated in an oil bath. The flask was heated to 42 ° C. while stirring and held at 42 ° C. for 60 minutes, and then 105 parts (21 parts of resin) of the resin particle dispersion (1) was added and gently stirred. Thereafter, the pH in the system was adjusted to 6.0 with a 0.5 mol / liter aqueous sodium hydroxide solution, and then heated to 95 ° C. while stirring was continued. During the temperature increase up to 95 ° C, the pH in the system usually drops to 5.0 or less, but here, an aqueous sodium hydroxide solution is added dropwise to keep the pH from dropping to 5.5 or less. did. After completion of the reaction, the mixture was cooled, filtered, thoroughly washed with ion exchange water, and then solid-liquid separated by Nutsche suction filtration. And it re-dispersed in 40 degreeC ion-exchange water, and stirred and wash | cleaned for 15 minutes at 300 rpm. This washing operation was repeated 5 times, followed by solid-liquid separation by Nutsche suction filtration, and then vacuum drying for 12 hours to obtain cyan toner particles (1). When the particle size of the toner particles was measured with a Coulter counter, the cumulative volume average particle size D ₅₀ was 5.8 μm, and the volume average particle size distribution index GSDv was 1.25. Further, the shape factor SF1 of the toner particles obtained from the shape observation by Luzex was 133 potato shape.
To 50 parts of the toner particles, 1.5 parts of hydrophobic silica (manufactured by Cabot, TS720) was added and mixed by a sample mill to obtain cyan electrostatic image developing toner (1).
Then, using a ferrite carrier having an average particle diameter of 50 μm coated with 1% of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd., Mw 75,000), the above externally added toner is weighed so that the toner concentration becomes 5%. Both were stirred and mixed with a ball mill for 5 minutes to prepare an electrostatic charge image developer (1).

<Evaluation of toner>
The electrostatic charge image developing toner (1) is a flow tester CFT-500A type manufactured by Shimadzu Corporation, and the temperature when it becomes 10 ⁴ Pa · s under a pressure of 10 MPa and 1 MPa is 24 ° C. and 102 ° C., respectively. A temperature difference of 78 ° C. was observed.
The magenta, yellow and black electrostatic image developing toner (1) is a magenta pigment (CI Pigment Red 57: 2), a yellow pigment (CI Pigment Yellow 97) or a black pigment instead of a cyan pigment. It was prepared in the same manner as the cyan electrostatic image developing toner (1) except that (carbon black R330) was used. For magenta, yellow and black electrostatic image developing toner (1), the temperature at 10 ⁴ Pa · s under a pressure of 10 MPa and 1 MPa using a flow tester CFT-500A manufactured by Shimadzu Corporation As a result, the same results as those of the cyan electrostatic charge image developing toner (1) were obtained.

<Nip configuration of fixing device>
The results of experiments conducted to determine the nip configuration of this device are shown below. FIG. 6 shows the toner viscosity at a flow tester applied pressure at 25.degree. As a result, the viscosity of the toner is reduced by applying pressure, the viscosity is rapidly reduced at 3 MPa or more, and is approximately saturated at about 10 ⁴ Pa · s at 5 MPa or more. As the applied pressure, it is preferable to set the pressure so that the toner viscosity is 10 ⁵ Pa · s or less in FIG. 6 because the toner easily flows and high image gloss is easily obtained. Therefore, a roll pair is configured to pressurize at 5 MPa.

Next, the result of examining the relationship between the nip time and the image gloss by changing the roll speed (conveyance speed) is shown in FIG. The paper used was 127 gsm of OK topcoat N. As the image, a solid image in which cyan, magenta, and yellow toners were each transferred to 4 g / m ² paper was used.
From FIG. 7, the image gloss increases with the nip time, but is almost saturated in the vicinity of 80 ms. Accordingly, if the pressure is 5 MPa (50 kgf / cm ² ) or more and the nip time is 80 ms or more, the fixing device can provide high gloss performance. However, in order to satisfy this condition with one roll pair, a large-diameter roll, a large load, and a housing for supporting a large load are required, and the apparatus becomes very large.
In this embodiment, it is assumed that the image gloss increase rate (the increase rate of the image gloss with respect to the nip time) is calculated from FIG. 6, and the point where the image gloss increase rate is 0.2% / ms or less is saturated.

  In order to reduce the size of the apparatus, a plurality of pressurizing units were provided adjacent to each other, and the following experiment was performed in order to determine the interval between them. In FIG. 8, five pressurizing portions that pressurize at 5 MPa are provided, and the interval between them is changed, and the pressure fixing is performed five times. The obtained result is shown. At this time, the process speed of the fixing device was set to 50 mm / s. From this result, when the interval is 2 s or more, the gross change is drastically reduced. This shows that the toner in this embodiment has a viscosity that allows the toner to flow until 1.5 seconds after the pressure is released. Ordinary thermoplastic toners are cured in about 0.1 s after being heated and pressed and fixed at room temperature, but the toner of this embodiment has a characteristic characteristic that the viscosity can be maintained after the pressure is released. Therefore, it can be seen that high gloss can be obtained even if a plurality of pressurizing portions are arranged with a nip interval of about 1 s.

Next, the result of investigating the increase in image gloss due to the number of pressurizations is shown in FIG. The process speed of the fixing device was 50 mm / s, and the nip interval between each was 1 s. Here, “high pressure × 4” means that the pressure of 5 mm and nip width of 1 mm is provided four times, and “high pressure × 3 + low pressure × 1” means that the pressure of 5 MPa and nip width of 1 mm is three times and the most downstream side. A pressure of 0.5 MPa and a nip width of 5 mm is provided. Further, for comparison, the result of fixing the toner of Comparative Example 1 described later under the same condition as “high pressure × 4” is also shown.
Note that “high pressure × 3 + low pressure × 1” was performed using the fixing device shown in FIG. Further, in the “high pressure × 4”, in the fixing difference of FIG. 2, the most downstream pressure member 9 and the counter member 10 are made of SUS (stainless steel) of φ30 like the other pressure members and the counter member, The load was adjusted by a pressure mechanism so that the nip width at a pressure of 5 MPa or more was 1 mm.

  In FIG. 9, substantially the same image gloss is obtained for “high pressure × 4” and “high pressure × 3 + low pressure × 1”. This indicates that the toner applied with a high pressure a plurality of times has a gradually lower viscosity, and the contribution of pressure is reduced. Further, it is shown that thermoplastic toner has a small change in image gloss and that this configuration is superior.

Moreover, the result of evaluating the rough paper dropout grade is shown in FIG. In this evaluation, the density unevenness generated in the concave portion of the paper due to the pressure unevenness was evaluated by the grade as the loss of pressure for the image in which the black entire surface was fixed to 127 gsm of the Rezac 66 as the uneven paper.
Grade is
2: A missing part is visible 1: A slight missing part is visible, but I do not mind 0: No missing The fixing conditions are a total pressure of 3 to 10 pressurization with a nip width of 1 mm at 5 MPa, and a pressurization with a nip width of 1 mm at 5 MPa. Were compared three times with the most downstream low pressure (high 3 + low 1) with a nip width of 5 mm at 0.5 Mpa on the most downstream side. As a result, when the number of pressurizations is increased, the rough paper removal grade is improved, but even if the pressurization is performed 10 times, it does not become 0. It can be seen that it can be improved. This is because the most downstream pressure portion is made of rubber, so that the nip can easily follow the unevenness of the rough paper. When a strong pressure is applied, the risk of paper deformation and paper wrinkles increases, so it is necessary to suppress stress as much as possible. Therefore, this configuration, in which high pressure is applied until the toner viscosity is reduced to the required value and the final pressurizing part is low, is excellent in rough paper unevenness followability and has good fixability, and paper stress is further reduced. Reduced.

(Comparative Example 1)
In the comparative examples, toners were prepared and evaluated in the same manner as in the examples except that the following resin particle dispersion (C1) was used instead of the resin particle dispersion (1) used in the examples.
<Preparation of toner particles for comparison (1), preparation of resin particle dispersion (C1) (styrene-butyl methacrylate, 2-hydroxyethyl methacrylate)>
In a round glass flask, 300 parts of ion-exchanged water and 1.5 parts of TTAB (tetradecyltrimethylammonium bromide, manufactured by Sigma Co., Ltd.) are placed, and nitrogen bubbling is performed for 20 minutes. The temperature was raised to ° C. 40 parts of n-butyl methacrylate monomer was added, and the mixture was further stirred for 20 minutes. Initiator V-50 (2,2′-azobis (2-methylpropionamidine) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) 0.5 part was dissolved in 10 parts ion-exchanged water in advance, and then in a flask. It was thrown into. Ion exchange at 65 ° C for 3 hours, 50 parts of styrene monomer, 25 parts of n-butyl acrylate monomer, 2 parts of 2-hydroxyethyl methacrylate and 0.8 part of dodecanethiol dissolved in 0.5 part of TTAB The emulsified liquid emulsified in 100 parts of water was continuously charged into the flask using a metering pump over 2 hours. The temperature was raised to 70 ° C. and held for another 2 hours to complete the polymerization.
A resin particle dispersion (C1) having a weight average molecular weight Mw of 19,000, an average particle diameter of 280 nm, and a solid content of 25% by weight was obtained. After the resin was air-dried at 40 ° C., when the glass transition temperature was analyzed from −150 ° C. with a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, a glass transition due to polybutyl methacrylate was observed around 25 ° C., and 42 ° C. The glass transition by the copolymer considered to consist of a styrene-butyl acrylate-2-hydroxyethyl methacrylate copolymer was observed in the vicinity (glass transition temperature difference: 17 ° C.).
An electrostatic charge image developing toner (C1) was prepared in the same manner as in Example 1, and the particle size of the toner particles was measured with a Coulter counter. The cumulative volume average particle size D ₅₀ was 5.5 μm, and the volume average particle size distribution index GSDv. Was 1.19. The shape factor SF1 of the toner particles obtained from the observation of the shape with Luzex was a 129 potato shape.
As in Example 1, the temperature when the flow tester CFT-500A manufactured by Shimadzu Corporation is 104 Pa · s under a pressure of 10 MPa and 1 MPa is 120 ° C. and 110 ° C., respectively. A difference was observed.

(Example 2)
In Example 2, the fixing device shown in FIG. 3 was used. That is, it is substantially the same as Example 1 except having comprised the pressurization member 1 with the single roll.

(Example 3)
In Example 3, the fixing device shown in FIG. 4 was used. That is, it is substantially the same as Example 1 except having comprised the opposing member 2 with the single roll.

Example 4
In Example 4, the fixing device shown in FIG. 5 was used. That is, it is substantially the same as Example 1 except that the most downstream pressure member 1-4 is a pressure roll not provided with an elastic layer, and the opposing member 9 is an elastic fixing member. Further, belt tension rolls 3 ′ and 4 ′ are provided on the downstream side of the pressure member 1-4 and the counter member 9.

  Even when the fixing devices of Examples 2 to 4 were used, a high gloss image was obtained, and even when rough paper was used, no image omission occurred.

1, 1-1, 1-2, 1-3, 1-4 Pressure member 2, 2-1, 2-2, 2-3 Opposing member 3, 4 Belt tension roll 5, 6 Belt (endless belt) )
7 Transfer material 8 (Low pressure) Pressure member 9 (Low pressure) Opposing member 10 Primary transfer portion 11 Photosensitive drum 12 Charger 13 Laser exposure device 14 Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Drum cleaner 20 Secondary transfer portion 22 Secondary transfer roll 25 Backup roll 30Y, 30M, 30C, 30K Image forming unit 31 Drive roll 40 Controller 51 Conveying roll 55 Conveying belt 60 Fixing device

Claims (6)

It has a plurality of nip parts composed of a pressure member and a counter member,
A transfer means for transferring the transfer material onto which the toner has been transferred to the nip;
The toner satisfies the following formula (1),
It has a nip part FH and a nip part F1 in this order in the transfer direction of the transfer material,
The applied pressure P1 at the nip portion F1 is less than the applied pressure PH of the nip portion FH having the maximum applied pressure in the nip portion upstream of the nip portion F1 in the transport direction,
A nip width N1 in the nip portion F1 exceeds a nip width NH in the nip portion FH.
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
(In the formula (1), T (10 MPa) represents a temperature at which the viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 10 MPa, and T (1 MPa) represents a viscosity of 10 ^{4 at} a flow tester applied pressure of 1 MPa. (It represents the temperature when Pa · s is reached.)   The fixing device according to claim 1, wherein the pressure member and / or the opposing member in the nip portion F <b> 1 has an elastic layer.   3. The fixing device according to claim 1, wherein the nip portion F <b> 1 is provided on the most downstream side in the conveyance direction of the transfer material of the plurality of nip portions.   The fixing device according to claim 1, further comprising an endless belt disposed between the pressure member and the facing member along the pressure member and / or the facing member. An image carrier,
Charging means for charging the surface of the image carrier;
Exposure means for forming an electrostatic latent image on the surface of the image carrier;
Developing means for developing the electrostatic latent image into a toner image with a developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to a transfer target;
Fixing means for fixing the toner image transferred to the transfer target,
An image forming apparatus comprising the fixing device according to claim 1 as the fixing unit. A charging step for charging the surface of the image carrier;
A latent image forming step of forming a latent image on the surface of the charged image carrier;
A developing step of developing a latent image formed on the surface of the image carrier with a developer containing at least toner to form a toner image;
A transfer step of transferring a toner image formed on the surface of the image carrier to a transfer target;
A fixing step of fixing the toner image transferred to the transfer body,
The toner satisfies the following formula (1),
In the fixing step, pressurizing a plurality of times,
After pressurizing with the applied pressure PH, pressurize with the applied pressure P1,
PH and P1 satisfy PH>P1;
When the nip width to be pressurized with PH is NH and the nip width to be pressurized with P1 is N1,
N1> NH
An image forming method characterized by satisfying:
20 ° C. ≦ T (1 MPa) −T (10 MPa) ≦ 120 ° C. (1)
(In the formula (1), T (10 MPa) represents a temperature at which the viscosity becomes 10 ⁴ Pa · s at a flow tester applied pressure of 10 MPa, and T (1 MPa) represents a viscosity of 10 ^{4 at} a flow tester applied pressure of 1 MPa. (It represents the temperature when Pa · s is reached.)

Images