JP2004219674A - Mixing device, toner manufacturing method and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixing device which mixes toner manufacturing powder (toner mother particles) and additive agent so that the additive agent is appropriately prevented from isolating or aggregating. <P>SOLUTION: The mixing device 100' is provided with a stirring/mixing chamber 120 in which the toner manufacturing powder and the additive agent are charged, a rotary shaft 150 which is rotated by a rotary-driving means, and a stirring blade 170 fixed on the rotary shaft 150. Besides, a cylindrical member 129 is installed in the stirring/mixing chamber 120. The cylindrical member 129 is provided with a cylindrical insulating layer 1292 constituted of insulating material, a 1st conductive layer 1291 constituted of conductive material and formed on the outer periphery side of the insulating layer 1292, and a 2nd conductive layer 1293 constituted of conductive material and formed on the inner periphery side of the insulating layer 1292. The surface of the 1st conductive layer 1291 is electrified with the same polarity as that of the additive agent when being connected to the power source. Then, the additive agent is prevented from sticking to the inside wall surface of the stirring/mixing chamber 120. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mixing device, a method for producing a toner, and a toner.
[0002]
[Prior art]
As the electrophotographic method, many methods are known. In general, a step (exposure step) of forming an electric latent image on a photoconductor by various means using a photoconductive substance, and A developing step of developing the latent image using toner, a transfer step of transferring the toner image to a transfer material (recording medium) such as paper, and a fixing step of fixing the toner image by heating using a fixing roller or the like. have.
[0003]
The toner used in the electrophotographic method as described above is manufactured, for example, through the following steps. First, materials mainly including a resin component are mixed and kneaded to obtain a kneaded material. Thereafter, the kneaded material is pulverized to obtain toner base particles. Thereafter, an external additive is externally added to the toner base particles to complete the toner.
[0004]
In the case of performing the external addition process, generally, a process of stirring and mixing the toner base particles and the external additive is performed using a stirring and mixing device (for example, see Patent Documents 1 and 2).
[0005]
However, when the external addition processing of the toner is performed using the conventional stirring and mixing apparatus, when the addition amount of the external additive becomes relatively large (for example, when the addition amount of the external addition exceeds 2 wt%), the stirring and mixing processing is performed. Accordingly, there is a problem that the ratio of the external additive that does not adhere to the toner base particles, that is, the ratio of the external additive (free external additive) released from the toner base particles increases. In addition, when the ratio of the free external additive increases, the free external additive adheres to the wall surface of the stirring and mixing device, and the particles of the free external additive aggregate with each other. In some cases, it was mixed.
[0006]
If a large amount of free or agglomerated external additives is mixed into the toner product, the quality will cause streaks on the image due to sticking to the wire during charging, adverse effects such as unstable charging and image fixing. Aggregation occurs in the apparatus, and adverse effects such as changing the charging characteristics of the toner are likely to occur.
[0007]
Also, when the amount of the free external additive is large, scattering of the fine particles (free external additive) into the air and the like are liable to occur, and there is a concern about the operational safety of the toner production.
[0008]
[Patent Document 1]
JP-A-8-173783 (page 5)
[Patent Document 2]
JP-A-63-244056 (page 3)
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a mixing device capable of mixing a toner production powder (toner base particles) and an external additive so that liberation and aggregation of the external additive are suitably prevented, and to use the mixing device. It is another object of the present invention to provide a method for manufacturing a toner, and to provide a toner manufactured by using the mixing apparatus and the manufacturing method.
[0010]
[Means for Solving the Problems]
Such an object is achieved by the following (1) to (14) of the present invention.
[0011]
(1) a stirring and mixing chamber into which a powder for toner production and an external additive are charged;
A rotation shaft that is rotated by the rotation driving means,
A stirring blade fixed to the rotating shaft, and disposed in the stirring and mixing chamber,
A mixing apparatus for stirring and mixing the toner production powder and the external additive, and externally adding the external additive to the toner production powder,
A mixing device comprising a charging unit for charging an inner wall surface of the stirring and mixing chamber to the same polarity as the external additive.
Accordingly, a mixing device capable of mixing the toner manufacturing powder (toner base particles) and the external additive can be provided so that the liberation and aggregation of the external additive are suitably prevented.
[0012]
(2) A flow path is provided inside the wall surface of the stirring / mixing chamber, and charged powder charged to the same polarity as the external additive by friction charging is moved in the flow path to form an inner wall surface of the stirring / mixing chamber. The mixing device according to the above (1), which charges the toner.
This makes it possible to easily and safely charge the inner wall surface of the stirring and mixing chamber.
(3) The mixing device according to (2), wherein the average particle size of the charged powder is 0.05 to 0.3 mm.
Thereby, the efficiency of charging the inner wall surface of the stirring and mixing chamber due to the movement of the charged powder can be made particularly excellent while ensuring the fluidity of the charged powder sufficiently.
[0013]
(4) The mixing device according to the above (2) or (3), wherein the flow rate of the charged powder is 10 to 1000 g / sec.
Thereby, the charging efficiency of the inner wall surface of the stirring and mixing chamber due to the movement of the charged powder can be made particularly excellent. Further, the flow resistance of the charged powder can be reduced, and the charged powder can flow smoothly.
[0014]
(5) The mixing device according to any one of the above (2) to (4), wherein the charged powder contains air in advance.
Thereby, the fluidity of the charged powder can be improved.
(6) The mixing device according to any one of (2) to (5), wherein a spiral guide path is formed in the flow path.
Thereby, the charged powder can be easily and uniformly flown in the flow path, and the efficiency of charging the inner wall surface of the stirring and mixing chamber can be made particularly excellent.
[0015]
(7) The mixing device according to any one of (1) to (6), wherein an inner wall surface of the stirring and mixing chamber is charged to the same polarity as the external additive by applying a voltage.
Thereby, the inner wall surface of the stirring and mixing chamber can be charged relatively easily.
(8) The mixing device according to (7), wherein the absolute value of the voltage is 1 to 10 kV.
Thereby, release and aggregation of the external additive can be more effectively prevented.
[0016]
(9) An insulating layer made of an insulating material is interposed between two conductive layers arranged so as to surround at least a part of the stirring and mixing chamber and made of a conductive material. Having a cylindrical member,
The mixing device according to (7) or (8), wherein the voltage is applied such that a layer provided on the outer peripheral surface side of the member among the conductive layers functions as an electrode plate.
Thereby, release and aggregation of the external additive can be more effectively prevented.
[0017]
(10) A method for producing a toner, comprising a step of stirring and mixing a toner production powder and an external additive using the mixing apparatus according to any one of (1) to (9).
This makes it possible to provide a toner in which the release of the external additive is suppressed.
(11) A toner manufactured using the mixing device according to any one of (1) to (9).
This makes it possible to provide a toner in which the release of the external additive is suppressed.
[0018]
(12) A toner produced by the production method according to the above (10).
This makes it possible to provide a toner in which the release of the external additive is suppressed.
(13) The toner according to the above (11) or (12), wherein the content of the external additive is 0.5 to 5% by weight.
Thereby, the function of the external additive can be more effectively exerted while sufficiently preventing the adverse effect of the external additive liberated from the toner base particles (toner production powder).
[0019]
(14) The toner according to any one of (11) to (13) above, wherein a ratio of the external additive released from the toner base particles is 3 wt% or less.
As a result, it is possible to more effectively prevent the adverse effect of the external additive liberated from the toner base particles (toner production powder), improve the offset resistance and the like of the toner, and reduce the stickiness of the toner. Effectively prevented.
[0020]
Further, the mixing device has a gas introduction unit that sends a gas flow from the vicinity of the rotation shaft into the stirring and mixing chamber. The gas introduction unit mixes the liquid lubricant together with the gas flow from the gas introduction unit. Preferably, it is supplied into the mixing chamber.
Thereby, release and aggregation of the external additive can be more effectively prevented.
In addition, it is preferable that at least a part of the gas introduction part is formed along a peripheral surface of the shaft.
Thereby, release and aggregation of the external additive can be more effectively prevented.
[0021]
Preferably, the gas flow is a seal air for preventing powder from entering a bearing portion receiving the shaft.
This makes it possible to prevent the external additive and the powder for toner production from entering the bearing portion, and more effectively prevent the external additive from being released or aggregated.
Further, it is preferable that the gas introduction section is provided between the bearing section for receiving the shaft and the stirring and mixing chamber.
Thereby, release and aggregation of the external additive can be more effectively prevented.
[0022]
Further, it is preferable that the mist-like liquid lubricant is introduced into the stirring and mixing chamber.
Thereby, the liberation and aggregation of the external additive can be more effectively prevented, and the stickiness of the toner can be effectively prevented.
Further, it is preferable that the average particle size of the liquid lubricant introduced into the stirring and mixing chamber is 0.05 to 5 μm.
This makes it possible to more effectively prevent the liberation and aggregation of the external additive, and more effectively prevent the toner from sticking.
[0023]
Further, it is preferable that at least a part of the liquid lubricant adheres to the toner production powder, and functions as an external additive.
As a result, the offset resistance is improved, and the fluidity of the obtained toner powder (toner particles) is improved, so that blocking during transportation and stress in the image forming apparatus can be reduced.
[0024]
Preferably, the liquid lubricant is a silicone oil.
Thereby, at the time of fixing, image defects and the like can be more effectively prevented.
Further, the spray amount of the liquid lubricant is preferably 1 to 70 g / min.
This makes it possible to more effectively prevent the liberation and aggregation of the external additive, and more effectively prevent the toner from sticking.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a mixing device, a toner manufacturing method, and a toner according to the present invention will be described in detail with reference to the accompanying drawings.
<Mixing device and method for producing toner>
First, the mixing device of the present invention will be described.
FIG. 1 is a longitudinal sectional view schematically showing the configuration of the first embodiment of the mixing apparatus of the present invention, and FIG. 2 is a schematic enlarged view of a portion B of the mixing apparatus shown in FIG. FIG. 3 is a longitudinal sectional view, and FIG. 3 is a perspective view schematically showing a driving unit to which the mixing device shown in FIG. 1 is mounted.
[0026]
The mixing device 100 is a device that mixes a powder for toner production (toner mother particles), which will be described in detail later, and an external additive.
The mixing apparatus 100 is roughly described as an apparatus main body 110, a stirring and mixing chamber 120, a water cooling chamber 130, a bearing unit 140, a rotating shaft 150, a first seal member 160, a second seal member 161, a stirring blade 170, a bearing 180, and the like. It is comprised by.
The apparatus main body 110 is, for example, a cylindrical member made of ceramics or stainless steel, and a first partition plate 111 is provided at a substantially central portion thereof. A bearing unit 140 is provided below the first partition plate 111, and a second partition plate 112 is provided below the bearing unit 140.
[0027]
The first partition plate 111 is fixed to the inner wall of the apparatus main body 110 by, for example, welding. The inside of the second partition plate 112 is fixed to the bearing unit 140 using screws 113 and brackets 114, and the outside thereof is fixed to the inner wall of the apparatus main body 110 by, for example, welding. Further, inside the bearing unit 140, the second seal member 161 is fixed by press-fitting, and the bearing 180 is disposed so as to abut on the rotating shaft 150 to form a bearing portion. Further, inside the first partition plate 111, the first seal member 160 is fixed by press-fitting.
[0028]
By disposing the first partition plate 111 and the second partition plate 112 in the apparatus main body 110, the apparatus main body 110 is defined as three rooms. Of these three chambers, the agitating and mixing chamber 120 is located at the top, the water cooling chamber 130 is located at the center, and the mounting chamber 190 is located at the bottom. Each of these chambers (the stirring and mixing chamber 120, the water cooling chamber 130, and the mounting chamber 190) is configured to be liquid-tight with each other.
[0029]
The stirring and mixing chamber 120 is a chamber into which a powder used as a material of the toner, that is, a powder for toner production and an external additive are charged and mixed. Further, the water cooling chamber 130 is connected to a cooling water inlet 131 and a cooling water outlet 132 provided in the apparatus main body 110, and while cooling water is introduced into the water cooling chamber 130 from the cooling water inlet 131, The cooling water after cooling is discharged from the cooling water discharge port 132. Further, the mounting chamber 190 is a part to be mounted on the driving device 200 described later.
[0030]
On the other hand, a rotary shaft 150 is provided in a hole formed near the center of the first partition plate 111 and the second partition plate 112 described above. The upper end of the rotating shaft 150 protrudes into the mixing chamber 120. A stirring blade 170 is fixed to the protruding portion of the rotating shaft 150 with a bolt 151. Accordingly, the rotation of the rotating shaft 150 causes the stirring blade 170 to rotate integrally, and thereby the powder introduced into the stirring and mixing chamber 120 is stirred and mixed. A lower end portion of the rotating shaft 150 is formed with a bifurcated engaging portion 152, and is configured to be connected to a drive shaft 210 of a motor described later.
[0031]
The rotating shaft 150 is rotatably supported by a bearing 180 provided in the bearing unit 140. The bearing 180 employs, for example, a ball bearing. Further, a first seal member 160 is provided at a portion of the first partition plate 111 facing the rotation shaft 150. Further, a second seal member 161 is provided at a position higher than the position where the bearing 180 of the bearing unit 140 is provided. By arranging the first seal member 160 and the second seal member 161 in this manner, the configuration is such that the powder charged into the stirring and mixing chamber 120 is prevented from entering the bearing 180. ing.
[0032]
In addition, an upper lid 121 that covers the upper part of the stirring and mixing chamber 120 is detachably provided on the upper part of the apparatus main body 110, and the powder introduced into the stirring and mixing chamber 120 at the time of stirring and mixing. Is not scattered.
During the stirring and mixing, the stirring blade 170 rotates at a high speed, so that a high-speed gas flow is generated in the stirring and mixing chamber 120, and the powder is stirred and mixed on the gas flow.
[0033]
Further, in the mixing device 100, a water cooling chamber 130 is provided near the rotation shaft 150 so as to surround the rotation shaft 150. Thus, the provision of the water cooling chamber 130 cools the bearing unit 140 and the rotating shaft 150. As a result, in the mixing device 100, deterioration of the components due to heat can be suitably prevented, and a sufficient shielding effect can be maintained for a long period of time.
[0034]
Further, the mixing device 100 has a charging means for charging the inner wall surface 1201 of the stirring and mixing chamber 120 to the same polarity as the external additive. As described above, the present invention is characterized in that the mixing device has the charging unit. By providing the charging means in this manner, in the external addition process, the external additive is electrically repelled from the inner wall surface, thereby preventing the external additive from adhering to the inner wall surface of the stirring and mixing chamber. it can. Further, the external additive can be efficiently attached to the toner production powder (toner base particles), and the external additive released from the toner production powder (toner base particles) in the finally obtained toner The amount of (free external additive) can be reduced. In addition, it is possible to prevent the particles of the external additive from aggregating and becoming an external additive having a large particle diameter. As a result, it is possible to prevent the aggregate of the external additive from being mixed into the toner product.
[0035]
In the mixing apparatus 100 of the present embodiment, as a means (charging means) for charging the inner wall surface of the stirring and mixing chamber 120 to the same polarity as the external additive, the mixing wall is formed inside the apparatus main body 110 constituting the wall surface of the stirring and mixing chamber 120. And a charged substance 127 flowing through the flow path 126. A feeder (not shown) for flowing the charged substance 127 into the flow path 126 is connected to the flow path 126.
Here, FIG. 2 is a cross-sectional view showing, on an enlarged scale, a part of the apparatus main body 110 constituting the stirring and mixing chamber 120. As shown in FIG. 2, in the present embodiment, a flow path 126 is formed between the inner wall 124 and the outer wall 125. The inner wall 124 is made of, for example, an insulating material such as ceramics.
[0036]
For example, when a negatively-charged external additive 71, which will be described in detail later, is used as the external additive, the inner wall 124 is polarized by flowing a negatively charged material 127 through the flow path 126, The channel 126 side can be charged positively, and the stirring and mixing chamber 120 side can be charged negatively. Thereby, the inner wall surface 1201 of the stirring and mixing chamber 120 can be negatively charged. As a result, the negatively charged external additive 71 and the inner wall surface 1201 of the stirring and mixing chamber 120 are electrically repelled, and the external additive 71 can be effectively prevented from adhering to the inner wall surface 1201. At the same time, the amount of the free external additive can be reduced to prevent the free external additive and the aggregate of the external additive from being mixed into the toner product.
[0037]
Similarly, when a positively charged external additive 71 is used, the inner wall surface 1201 of the stirring and mixing chamber 120 can be positively charged by flowing a positively charged charged substance into the channel 126. As a result, the positively-charged external additive 71 and the inner wall surface 1201 of the stirring and mixing chamber 120 are electrically repelled, and the adhesion of the external additive 71 to the inner wall surface 1201 is effectively reduced in the same manner as described above. In addition to reducing the amount of the free external additive, the free external additive and the aggregate of the external additive can be prevented from being mixed into the toner product.
[0038]
Examples of the charged substance 127 flowing in the flow path 126 include a charged powder that is positively or negatively charged by frictional charging.
Examples of the negatively charged powder that is negatively charged by frictional charging include powders of a fluororesin such as polytetrafluoroethylene (PTFE), vinyl chloride, polyethylene, and polypropylene.
Examples of the positively charged powder that is positively charged by frictional charging include powders of chitosan, acetate, glass, nylon, and the like.
[0039]
The average particle size of such a charged powder is preferably about 0.05 to 0.3 mm. When the average particle size of the charged powder is less than the lower limit, the flow rate of the charged powder is small, the charge is small, and the effect is small. On the other hand, when the average particle size exceeds the above upper limit, the flashing phenomenon of the powder due to aeration may not be sufficiently exhibited, and the fluidity of the charged powder may be reduced. In addition, the effect of preventing the adhesion to the wall of the mixing tank is reduced due to the small charge.
[0040]
The flow rate of the charged powder (charged substance 127) is not particularly limited, but is preferably 10 to 1000 g / sec. If the flow rate is less than the lower limit, the charging efficiency of the inner wall surface 1201 tends to be significantly reduced. On the other hand, when the flow rate exceeds the upper limit, the resistance (flow resistance) when flowing the charged powder (charged substance 127) tends to increase.
[0041]
Before flowing the charged powder (charged substance 127) through the flow channel 126, it is preferable that air (gas) is previously contained in the charged powder (aeration). Thereby, the fluidity of the charged powder can be increased.
Furthermore, it is preferable that, for example, a spiral guide path 128 is formed in the flow path 126. Thereby, the charged powder can be easily and uniformly flown in the flow channel 126. Thereby, the inner wall surface 1201 of the stirring and mixing chamber 120 can be charged efficiently and more uniformly.
[0042]
As described above, by charging the inner wall surface 1201 of the stirring and mixing chamber 120 to the same polarity as the external additive, the external additive is less likely to adhere to the inner wall surface 1201 of the stirring and mixing chamber 120 in the external adding process. And it becomes easy to mix uniformly. Further, since the external additive is prevented from adhering to the inner wall surface 1201, it is possible to more effectively prevent the aggregate of the external additive from being mixed into the toner product. As a result, it is possible to more effectively prevent the occurrence of a problem on an image due to mixing of the released external additive (free external additive) into the toner product.
[0043]
Further, when the external additive is discharged from the mixing apparatus 100 after the completion of the external additive treatment step, the amount of the external additive released is small, and the diffusion of the fine particles can be suppressed. In addition, since the external additive hardly adheres to the inner wall surface 1201, it is easy to clean the mixing device 100 and replace components of the mixing device 100.
Conventionally, a large amount of the external additive is prescribed in consideration of the amount of adhesion to the inner wall surface. However, since the external additive can be prevented from adhering to the inner wall surface 1201, the external additive is formulated. The amount can be reduced.
[0044]
The surface charge density of the inner wall surface 1201 is not particularly limited, but is always 10 to 100 [nC / cm. ² ] Is preferable. If the charge amount is less than the lower limit, the effect of the charging means may not be sufficiently obtained. On the other hand, when the charge amount exceeds the upper limit, the material to be charged is limited. Further, the base of the toner easily adheres to the wall surface.
[0045]
By the way, in the mixing apparatus 100 of the present embodiment, as described above, each of the seal members 160 and 161 is disposed at a position closer to the stirring and mixing chamber 120 than the position at which the bearing 180 is disposed. It has a function of preventing the powder mixed and stirred inside from entering the bearing 180. However, in order to maintain smooth rotation of the rotating shaft 150, the respective seal members 160 and 161 cannot be brought into close contact with the rotating shaft 150, so that there is inevitably a gap between the rotating shaft 150 and the respective seal members 160 and 161. Has a gap 158 formed therein. When the gap 158 is present, the powder may enter the bearing 180, hinder the smooth bearing function of the bearing 180, and possibly prevent the rotation shaft 150 from rotating properly.
[0046]
Therefore, in the mixing apparatus 100, a compressed air inlet 115 is provided on the outer wall of the apparatus main body 110, and further, an air inlet (gas inlet) communicating the compressed air inlet 115 and the gap 158 to the first partition plate 111. Part) 116 is formed. A compressed air introduction device such as a compressor (not shown) is connected to the compressed air introduction port 115.
[0047]
In the mixing device 100 having the above configuration, the compressed air introduced from the compressed air introduction port 115 is sent to the air introduction passage 116. The compressed air sent into the air introduction passage 116 flows into the stirring and mixing chamber 120 through a gap (gas introduction part) 158 formed between the first seal member 160 and the rotating shaft 150. As described above, by generating a gas flow in which the compressed air flows into the stirring and mixing chamber 120 from the gap portion 158, the flow of the powder from the stirring and mixing chamber 120 toward the bearing 180 can be prevented. It is possible to prevent powder from entering. That is, the introduced compressed air functions as seal air. As a result, in the mixing device 100, the smooth bearing function of the bearing 180 can be sufficiently maintained for a long period of time.
[0048]
Further, as described above, since the mixing device 100 is configured to cause the compressed air to flow into the stirring and mixing chamber 120 through the gap 158, the mixing device 100 may simply be configured to cause the air to flow into the stirring and mixing chamber 120. The pressure in the mixing chamber 120 increases. For this reason, a trap 122 is provided on the upper lid 121 that covers the stirring and mixing chamber 120.
A filter 123 is provided inside the trap 122. The filter 123 is configured to allow the passage of air but prevent the passage of powder. By providing such a trap 122, the inside of the stirring and mixing chamber 120 can be set to a pressure substantially equal to the atmospheric pressure.
[0049]
Further, in the mixing apparatus 100 of the present embodiment, in the external addition process, the liquid lubricant is formed into a mist (mist) together with the compressed air and introduced into the stirring and mixing chamber 120.
That is, the mixing apparatus 100 has a lubricant introduction port 117 on the outer wall of the apparatus main body 110, and further has a lubricant introduction path 118 communicating with the lubricant introduction port 117 in the first partition plate 111. ing. This lubricant introduction passage 118 joins with the air introduction passage 116. Further, a mist generating device (not shown) for converting the liquid lubricant into a mist is connected to the lubricant inlet 118 by, for example, an ultrasonic vibrator.
[0050]
In the mixing apparatus 100 having the above-described configuration, the mist-like liquid lubricant is introduced from the lubricant introduction port 117 at the time of stirring and mixing. Then, the liquid lubricant introduced from the lubricant introduction port 117 merges with the compressed air in the air introduction passage 116, and together with the compressed air, a gap formed between the first seal member 160 and the rotating shaft 150. It flows into the mixing chamber 120 through the section 158 (gas introduction section).
[0051]
As described above, in the mixing apparatus 100, the liquid lubricant is sprayed in the form of a mist when performing the external addition process. By spraying the liquid lubricant during the external addition process, release of the external additive can be more effectively prevented. Further, it is possible to prevent the liberated external additive from adhering to the inner wall surface 1201 of the stirring and mixing chamber 120 and prevent each particle of the external additive from aggregating and becoming an external additive having a large particle diameter. This makes it possible to more reliably prevent the aggregate of the external additive from being mixed into the toner product.
[0052]
Further, the sprayed liquid lubricant also adheres to the surface of the powder for toner production. By spraying the liquid lubricant in the form of a mist, the liquid lubricant can be attached to the toner production powder as finer particles. That is, in the present embodiment, a liquid lubricant can be applied to the toner base particles (powder for toner production) as an external additive. Thereby, the offset property of the obtained toner can be made particularly excellent. In addition, by applying the liquid lubricant as an external additive, the fluidity of the obtained toner powder (toner particles) is improved, thereby alleviating the blocking during transportation and the stress in the image forming apparatus. Can be. Further, by applying the liquid lubricant as an external additive, the obtained toner hardly causes aggregation between toner particles and hardly receives stress.
[0053]
The effect of the liquid lubricant as described above is obtained by being provided as an external additive. That is, when the liquid lubricant is dispersed in the powder for producing a toner, the above effects cannot be obtained.
As such a liquid lubricant, for example, carboxyl-modified silicone oil, straight silicone oil, polyether-modified silicone oil, epoxy-modified silicone oil, methacryl-modified silicone oil, amino-modified silicone oil, aminopolyether silicone oil, and the like are used. However, straight silicone oil is preferred. By using a silicone oil as the liquid lubricant, the fixing property of the finally obtained toner can be particularly excellent.
[0054]
The average particle size of the mist when the liquid lubricant is mist-shaped and mixed is not particularly limited, but is preferably from 0.05 to 5 μm, and more preferably from 0.1 to 1 μm. If the average particle size of the mist is less than the lower limit, the above effects may not be sufficiently obtained depending on the supply amount (spray amount) of the liquid lubricant. On the other hand, if the average particle size of the mist exceeds the upper limit, stickiness by the liquid lubricant may increase.
[0055]
The spray amount (supply amount) of the liquid lubricant is preferably 1 to 80 ml / min. If the spray amount (supply amount) of the liquid lubricant is less than the lower limit, the above-described effects may not be sufficiently obtained depending on the composition of the liquid lubricant, the particle size of the mist, and the like. However, it may be difficult to uniformly and externally add the liquid lubricant to the surface of the powder for toner production. On the other hand, if the spray amount (supply amount) of the liquid lubricant exceeds the above upper limit, the obtained toner may become sticky depending on the composition of the liquid lubricant, the particle size of the mist, and the like.
[0056]
Further, the above-mentioned liquid lubricant may be always (continuously) supplied into the stirring and mixing chamber 120 in the step of stirring and mixing the toner production powder and the external additive. , May be supplied intermittently (non-continuously).
Further, when a liquid lubricant is externally added to the surface of the powder for toner production, the amount of external addition (the ratio of the weight of the liquid lubricant contained in the toner to the weight of the entire toner) is not particularly limited. It is preferably 0.9 wt% or less, more preferably 0.5 wt% or less, and even more preferably 0.1 to 0.3 wt%. If the external additive amount of the liquid lubricant is too large, the obtained toner may be sticky, and the density may be reduced.
[0057]
FIG. 3 shows a driving device 200 on which the mixing device 100 having the above configuration is mounted. The driving device 200 has a motor inside, and the driving shaft 210 of the motor is configured to protrude above the driving device 200. The upper end of the drive shaft 210, that is, the engaging portion 211 is a portion that engages with the lower end of the rotary shaft 150, and engages with the forked engaging portion 152 formed at the lower end of the rotary shaft 150. It has a shape to be.
[0058]
Further, an annular flange 220 is formed at an upper portion of the driving device 200. The flange 220 is configured to fit into the lower part of the mounting chamber 190.
Further, a lock claw 221 is formed on the flange 220 so as to protrude therefrom. On the other hand, a concave portion 119 is formed in the apparatus main body 110 at a position corresponding to the lock claw 221 at an inner peripheral position thereof. Therefore, by mounting the mixing device 100 on the upper portion of the driving device 200 such that the locking claw 221 is engaged with the concave portion 119, it is possible to prevent the device main body 110 from rotating on the driving device 200 when the mixing device 100 is used. It can be suitably prevented.
[0059]
As described above, when the mixing device 100 is mounted on the driving device 200, the flange 220 of the driving device 200 fits into the mounting chamber 190 of the device main body 110, and the engaging portions 152 and 211 are engaged with each other. By the combination, the drive shaft 210 is connected to the rotation shaft 150. The drive device 200 is provided with a timer 230 for setting the stirring time, an on / off switch 240 for starting and stopping, a speed control switch 250 for changing the rotation speed of the drive shaft 210, and the like.
[0060]
As described above, the stirring and mixing process of the toner manufacturing powder and the external additive is performed in a state where the mixing device 100 is mounted on the driving device 200. Specifically, first, the upper lid 121 is removed, the powder for toner production and the external additive are charged into the stirring and mixing chamber 120 at a predetermined mixing ratio, and the upper lid 121 is mounted on the upper portion of the apparatus main body 110 again. Subsequently, the stirring and mixing time is set by operating the timer 230, and the on / off switch 240 is turned on.
[0061]
Accordingly, the drive shaft 210 of the motor in the drive device 200 rotates, and the rotation shaft 150 connected to the drive shaft 210 via the engaging portions 211 and 152 also rotates. Accordingly, the stirring blade 170 connected to the rotating shaft 150 also rotates, and the powder for toner production and the external additive charged into the stirring and mixing chamber 120 are stirred and mixed. The rotation speed of the motor is not particularly limited, but may be, for example, a high-speed rotation of 10,000 to 30,000 rpm.
[0062]
As described above, in the mixing device 100, the inner wall surface 1201 of the stirring and mixing chamber 120 is charged to the same polarity as the external additive, so that the inner wall surface 1201 of the stirring and mixing chamber 120 is charged in the external adding process. Can be prevented from adhering, and the external additive can be efficiently adhered to the toner production powder (toner base particles). As a result, the amount of the external additive (free external additive) released from the toner production powder (toner base particles) in the finally obtained toner can be reduced. In addition, it is possible to prevent the particles of the external additive from aggregating and becoming an external additive having a large particle diameter. As a result, it is possible to prevent the aggregate of the external additive from being mixed into the toner product. As a result, the occurrence of problems on the image due to free external additives and the like can be effectively prevented.
[0063]
Further, according to the mixing apparatus 100, the liquid lubricant can be supplied into the stirring and mixing chamber 120 in the form of a mist in the external addition processing step. As a result, the release of the external additive and the adhesion of the released external additive to the inner wall surface 1201 of the stirring and mixing chamber 120 can be more effectively prevented, and the external additive can be coagulated into the toner product. Aggregation of aggregates can be more reliably prevented.
[0064]
Further, by spraying the liquid lubricant in the form of a mist, the liquid lubricant can be attached to the toner production powder as finer particles. Thereby, the offset resistance of the obtained toner can be improved, and the stickiness of the toner can be suppressed. In addition, the fluidity of the toner powder is improved, so that blocking during transportation and stress in the image forming apparatus can be reduced.
[0065]
The toner of the present invention obtained as described above is one in which free and aggregated external additives are prevented from being mixed. Therefore, the toner of the present invention can be suitably used for good image formation. Further, in the toner obtained as described above, since the liquid lubricant is externally added in the form of a mist, the offset is suitably prevented. Further, the toner obtained as described above has tackiness prevented, fluidity is improved, and blocking during transportation and stress in the image forming apparatus are reduced.
[0066]
Next, another embodiment of the mixing device of the present invention will be described.
FIG. 4 is a longitudinal sectional view schematically showing the configuration of the second embodiment of the mixing apparatus of the present invention.
Hereinafter, the mixing apparatus of the second embodiment will be described focusing on the differences from the first embodiment, and the description of the same items will be omitted.
[0067]
As shown in FIG. 4, in the mixing apparatus 100 ′ of the present embodiment, a cylindrical member 129 is installed on the inner wall of the stirring and mixing chamber 120 so as to surround the stirring and mixing chamber 120.
The cylindrical member 129 has an insulating layer 1292 having a cylindrical shape and made of an insulating material, and a first conductive layer 1291 made of a conductive material and formed on the outer peripheral side of the insulating layer 1292. And a second conductive layer 1293 formed of a conductive material and formed on the inner peripheral side of the insulating layer 1292. In other words, the cylindrical member 129 has two conductive layers made of a conductive material and an insulating layer made of an insulating material and interposed between the two conductive layers. .
[0068]
The first conductive layer 1291 of the tubular member 129 is connected to a power supply and functions as an electrode plate.
With such a structure, the inner peripheral surface of the cylindrical member 129, that is, the surface of the second conductive layer 1293 can be charged to the same polarity as the external additive by applying a voltage from a power supply. it can.
[0069]
That is, in the present embodiment, the cylindrical member 129 and the power supply function as a charging unit. As described above, in the present invention, the charging unit is not limited to the charging unit described in the first embodiment, but may be any unit that can charge the inner wall surface 1201 of the stirring and mixing chamber 120 to the same polarity as the external additive. Any object may be used.
When the inner wall surface of the stirring and mixing chamber is charged to the same polarity as the external additive by applying a voltage as in the present embodiment, the absolute value of the applied voltage is preferably 1 to 10 kV, More preferably, it is 5 kV.
[0070]
In the illustrated configuration, the cylindrical member 129 is installed in the stirring and mixing chamber 120, but the cylindrical member 129 is embedded in a wall that separates the stirring and mixing chamber 120 from the outside. Alternatively, it may be installed outside the stirring and mixing chamber 120 (wall).
Further, the tubular member 129 may have a layer other than the first conductive layer 1291, the insulating layer 1292, and the second conductive layer 1293. For example, an intermediate layer may be provided between the first conductive layer 1291 and the insulating layer 1292 or between the insulating layer 1292 and the second conductive layer 1293. Further, a coating layer may be formed on the outer peripheral surface side of the first conductive layer 1291 or on the inner peripheral surface side of the second conductive layer 1293.
[0071]
In the above description, for the sake of convenience, the mixing apparatus has been described from the upper part to the lower part in a configuration in which three rooms of a stirring mixing chamber, a water cooling chamber, and a mounting chamber are arranged in this order. The rooms may be arranged upside down, or may be arranged so that each room is adjacent in the horizontal direction (horizontal direction). Further, another room may be provided between these rooms.
[0072]
Next, the toner production powder and the external additive supplied to the above-described mixing apparatus will be described in detail.
First, the toner production powder will be described.
<Powder for toner production>
FIG. 5 is a vertical cross-sectional view schematically illustrating an example of the configuration of a kneader and a cooler used for manufacturing a toner. FIG. 6 is a model diagram of a differential scanning calorimetry analysis curve near the melting point of the block polyester obtained when differential scanning calorimetry is performed on the block polyester, and FIG. 7 is a flowchart for softening point analysis. Hereinafter, in FIG. 5, the left side will be referred to as “base end” and the right side will be referred to as “top end”.
In the present invention, the powder for toner production contains at least a resin as a main component (hereinafter, also simply referred to as “resin”).
[0073]
Hereinafter, an example of a constituent material of the powder for toner production and a production method will be described.
[Constituent materials]
The toner production powder can be produced using at least the raw material 5 containing a resin as a main component.
Hereinafter, each component of the raw material 5 used for manufacturing the toner manufacturing powder will be described.
1. Resin (binder resin)
Examples of the resin include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, and styrene- Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer, styrene-α-chloro Styrene-based resins such as methyl acrylate copolymer, styrene-acrylonitrile-acrylate copolymer, styrene-vinyl methyl ether copolymer, etc., containing a styrene or styrene-substituted homopolymer or copolymer, polyester-based resin , Epoxy resin, urethane modified Epoxy resin, silicone-modified epoxy resin, vinyl chloride resin, rosin-modified maleic resin, phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral Examples thereof include resins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, and one or more of these can be used in combination. Among them, a resin containing a polyester resin is particularly preferable. This makes it possible to relatively easily control the properties of the finally obtained toner, such as the elastic modulus and the chargeability.
Generally, a polyester resin is composed of an alcohol component (including a compound having two or more hydroxyl groups) and a carboxylic acid component (including a divalent or higher carboxylic acid or a derivative thereof).
[0074]
As the alcohol component, those having two or more hydroxyl groups can be used. For example, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butane Diol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol , Neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1, 3-pentanediol, 2-ethyl-1,3-hexanediol Chain diols such as 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or polyoxypropylene ( 2.2) -2,2-Bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2 , 2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6)- Alkylene oxide addition of bisphenol A such as 2,2-bis (4-hydroxyphenyl) propane 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adduct of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, cyclic diols such as an alkylene oxide adduct of hydrogenated bisphenol A, or sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, , 2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3 5-trihydroxyme Polyhydric alcohols having three or more hydroxyl groups such as tylbenzene are exemplified.
[0075]
As the carboxylic acid component, for example, a divalent or higher carboxylic acid or a derivative thereof (eg, acid anhydride, lower alkyl ester, etc.) can be used. For example, o-phthalic acid (phthalic acid), terephthalic acid, Isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, trimellitic acid, pyromellitic acid and derivatives thereof (eg, anhydride, lower Alkyl ester, etc.).
[0076]
The polyester-based resin may contain components other than the above-mentioned alcohol component and carboxylic acid component.
In the present invention, any resin may be used, but it is preferable to use a resin containing a block polyester and an amorphous polyester (hereinafter, also referred to as “polyester resin”), which will be described below.
[0077]
1-1. Block polyester
The block polyester is composed of a block copolymer having a crystalline block formed by condensing a diol component and a dicarboxylic acid component, and an amorphous block having lower crystallinity than the crystalline block.
(1) Crystalline block
The crystalline block has higher crystallinity than the amorphous block or the amorphous polyester. That is, the molecular arrangement structure is stronger and more stable than the amorphous block or the amorphous polyester. For this reason, the crystalline block contributes to improving the strength of the whole toner. As a result, the finally obtained toner is resistant to mechanical stress, and has excellent durability and storage stability.
[0078]
Incidentally, a resin having high crystallinity generally has a so-called sharp melt property as compared with a resin having low crystallinity. That is, when a resin having high crystallinity is measured for an endothermic peak at a melting point by differential scanning calorimetry (DSC), it has a property that an endothermic peak appears as a sharper shape than a resin having low crystallinity. I have.
On the other hand, the crystalline block has high crystallinity as described above. Therefore, the crystalline block has a function of imparting a sharp melt property to the block polyester. For this reason, this toner can maintain excellent shape stability even at a relatively high temperature (temperature near the melting point of the block polyester) at which the amorphous polyester described later is sufficiently softened. Therefore, this toner can exhibit sufficient fixability (fixing strength) in a wide temperature range.
[0079]
In addition, since such a crystalline block is included in the block polyester, in the present embodiment, the thermal sphering treatment described later can be performed efficiently (in a short time) and finally obtained. The circularity of the toner particles can be made particularly excellent.
Hereinafter, components constituting the crystalline block will be described.
[0080]
The diol component constituting the crystalline block may be any diol component having two hydroxyl groups, and examples thereof include an aromatic diol having an aromatic ring structure and an aliphatic diol having no aromatic ring structure. Examples of the aromatic diol include bisphenol A and an alkylene oxide adduct of bisphenol A, and examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, , 3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2 , 4-pentanediol, 3-methyl -1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, Chain diols such as polypropylene glycol and polytetramethylene glycol, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4- And cyclic diols such as cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, and alkylene oxide adduct of hydrogenated bisphenol A.
[0081]
As described above, the diol component constituting the crystalline block is not particularly limited, but it is preferable that at least a part of the diol component is an aliphatic diol, and it is more preferable that 80 mol% or more of the diol component is an aliphatic diol. More preferably, at least% is an aliphatic diol. Thereby, the crystallinity of the block polyester (crystalline block) can be made particularly high, and the above-mentioned effects become more remarkable.
[0082]
The diol component constituting the crystalline block has a linear molecular structure having 3 to 7 carbon atoms and has a hydroxyl group at both ends (general formula: HO- (CH ₂ ) _n It is preferable to include a diol represented by -OH (where n = 3 to 7). By including such a diol component, the crystallinity is improved and the friction coefficient is reduced, so that the diol component is resistant to mechanical stress, and particularly excellent in durability and storage stability. Such diols include, for example, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and the like, and among them, 1,4-butanediol Is preferred. By including 1,4-butanediol, the above-mentioned effects become particularly remarkable.
[0083]
When 1,4-butanediol is contained as a diol component constituting the crystalline block, it is more preferable that 50 mol% or more of the diol constituting the crystalline block is 1,4-butanediol, and 80 mol% or more of the diol is 1 mol. , 4-butanediol. As a result, the above-mentioned effects become more remarkable.
[0084]
As the dicarboxylic acid component constituting the crystalline block, a divalent carboxylic acid or a derivative thereof (e.g., acid anhydride, lower alkyl ester, etc.) can be used. For example, o-phthalic acid (phthalic acid), Terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid and derivatives thereof (eg, anhydrides, lower alkyl esters, etc.) and the like Is mentioned.
[0085]
As described above, the dicarboxylic acid component constituting the crystalline block is not particularly limited, but it is preferable that at least a part thereof has a terephthalic acid skeleton, and at least 50 mol% of the dicarboxylic acid component has a terephthalic acid skeleton. It is more preferable that 80 mol% or more of the compound has a terephthalic acid skeleton. As a result, the finally obtained toner has a particularly excellent balance of various properties required for the toner. However, the “dicarboxylic acid component” here refers to a dicarboxylic acid component when a block polyester is formed, and when the block polyester is adjusted (to form a crystalline block), the dicarboxylic acid component itself or Derivatives such as acid anhydrides and lower alkyl esters can be used.
[0086]
The content of the crystalline block in the block polyester is not particularly limited, but is preferably 5 to 60 mol%, and more preferably 10 to 40 mol%. If the content of the crystalline block is less than the lower limit, the effect of having the crystalline block as described above may not be sufficiently exhibited depending on the content of the block polyester and the like. On the other hand, when the content of the crystalline block exceeds the upper limit, the content of the amorphous block relatively decreases, so that the compatibility between the block polyester and the amorphous polyester described below may decrease. There is.
The crystalline block may contain a component other than the above-mentioned diol component and dicarboxylic acid component (for example, a trivalent or higher valent alcohol component or a trivalent or higher carboxylic acid component).
[0087]
(2) Amorphous block
The amorphous block has lower crystallinity than the above-described crystalline block. Further, the amorphous polyester described later also has lower crystallinity than the crystalline block. That is, the amorphous block has lower crystallinity than the crystalline block, similarly to the amorphous polyester described later.
[0088]
By the way, in a blend resin, generally, resins having greatly different crystallinities are hardly compatible with each other, and resins having a small difference in crystallinity are easily compatible with each other. Therefore, when the block polyester has an amorphous block, the compatibility (dispersibility) between the block polyester and the amorphous polyester described later is increased. As a result, phase separation (particularly, macro phase separation) between the block polyester and the amorphous polyester can be effectively prevented in the finally obtained toner, and the advantages of the block polyester and the amorphous The advantages of polyester can be sufficiently and stably exhibited.
[0089]
Hereinafter, components constituting the amorphous block will be described.
The diol component constituting the amorphous block may be any diol component having two hydroxyl groups, and examples thereof include an aromatic diol having an aromatic ring structure and an aliphatic diol having no aromatic ring structure. . Examples of the aromatic diol include bisphenol A and an alkylene oxide adduct of bisphenol A, and examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, , 3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2 , 4-pentanediol, 3-methyl -1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, Chain diols such as polypropylene glycol and polytetramethylene glycol, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4- And cyclic diols such as cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, and alkylene oxide adduct of hydrogenated bisphenol A.
[0090]
As described above, the diol component constituting the amorphous block is not particularly limited, but it is preferable that at least a part thereof is an aliphatic diol, and it is more preferable that 50 mol% or more of the diol component is an aliphatic diol. As a result, an effect of obtaining a fixed image having more excellent toughness (excellent bending resistance) can be obtained.
The diol component constituting the amorphous block preferably has at least a part thereof having a branched chain (side chain), and more preferably has at least 30 mol% of a branched chain. This has the effect of suppressing the regular arrangement, reducing the crystallinity, and improving the transparency.
[0091]
As the dicarboxylic acid component constituting the amorphous block, a divalent carboxylic acid or a derivative thereof (eg, acid anhydride, lower alkyl ester, etc.) can be used. For example, o-phthalic acid (phthalic acid) , Terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid and derivatives thereof (eg, anhydrides, lower alkyl esters, etc.) And the like.
[0092]
Thus, the dicarboxylic acid component constituting the amorphous block is not particularly limited, but it is preferable that at least a part thereof has a terephthalic acid skeleton, and at least 80 mol% of the dicarboxylic acid component has a terephthalic acid skeleton. More preferably, there is. As a result, the finally obtained toner has a particularly excellent balance of various properties required for the toner. However, the “dicarboxylic acid component” here refers to a dicarboxylic acid component when it is made into a block polyester, and when adjusting the block polyester (forming an amorphous block), the dicarboxylic acid component itself or And derivatives thereof such as acid anhydrides and lower alkyl esters.
The amorphous block may contain a component other than the above-mentioned diol component and dicarboxylic acid component (for example, a trivalent or higher valent alcohol component or a trivalent or higher carboxylic acid component).
[0093]
The average molecular weight (weight average molecular weight) Mw of the block polyester having a crystalline block and an amorphous block as described above is not particularly limited, but is 1 × 10 ⁴ ~ 3 × 10 ⁵ And preferably 1.2 × 10 ⁴ ~ 1.5 × 10 ⁵ Is more preferable. If the average molecular weight Mw is less than the lower limit, the mechanical strength of the finally obtained toner may be reduced, and sufficient durability (storability) may not be obtained. On the other hand, when the average molecular weight Mw is too small, cohesive failure tends to occur during fixing of the toner, and the offset resistance tends to decrease. On the other hand, when the average molecular weight Mw exceeds the above upper limit, grain boundary destruction is likely to occur at the time of fixing the toner, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.
[0094]
Glass transition point T of block polyester _g Although it is not particularly limited, it is preferably 50 to 75 ° C, more preferably 55 to 70 ° C. When the glass transition point is less than the lower limit, the storage stability (heat resistance) of the toner is reduced, and depending on the use environment, fusion between toner particles may occur. On the other hand, when the glass transition point exceeds the upper limit, the low-temperature fixability and the transparency are reduced. On the other hand, if the glass transition point is too high, the effect of the thermal sphering treatment described later may not be sufficiently exerted. The glass transition point can be measured according to JIS K7121.
[0095]
Softening point T of block polyester _1/2 Although it is not particularly limited, it is preferably from 90 to 160 ° C, and more preferably from 100 to 150 ° C. If the softening point is less than the lower limit, the storability of the toner may decrease, and sufficient durability may not be obtained. On the other hand, if the softening point is too low, cohesive failure tends to occur when fixing the toner, and the offset resistance tends to decrease. On the other hand, if the softening point exceeds the above upper limit, the grain boundary is likely to be broken at the time of fixing the toner, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased. The softening point T _1/2 For example, using a flow tester, a sample amount: 1 g, a die hole diameter: 1 mm, a die length: 1 mm, a load: 20 kgf, a preheating time: 300 seconds, a measurement start temperature: 50 ° C., and a heating rate: 5 ° C./min. Can be obtained as a temperature at a point on the flow curve corresponding to h / 2 in the analysis flowchart as shown in FIG.
[0096]
Melting point T of block polyester _m (The center value T of the peak when the endothermic peak of the melting point is measured by differential scanning calorimetry described later. _mp ) Is not particularly limited, but is preferably 190 ° C or higher, more preferably 190 to 230 ° C. If the melting point is lower than 190 ° C., there is a possibility that effects such as improvement in offset resistance may not be sufficiently obtained. On the other hand, if the melting point is too high, the material temperature must be set to a relatively high temperature in a kneading step described later. As a result, the transesterification reaction of the resin material is likely to proceed, and it may be difficult to sufficiently reflect the resin design on the finally obtained toner. The melting point can be determined, for example, by measuring an endothermic peak by differential scanning calorimetry (DSC).
[0097]
When the finally obtained toner is used in a fixing device having a fixing roller as described later, the melting point of the block polyester is set to T. _m (B) [° C.], the standard set temperature of the surface of the fixing roller is T _fix [° C], T _fix ≤T _m (B) ≦ (T _fix +100), and (T _fix +10) ≦ T _m (B) ≦ (T _fix +70) is more preferably satisfied. By satisfying such a relationship, the crystal component in the toner does not melt at the time of fixing the toner, so that the toner viscosity does not drop below a certain level, and the releasability from the fixing roller is secured.
[0098]
Further, the melting point of the block polyester is preferably higher than the softening point of the amorphous polyester described later. Thereby, the stability of the shape of the finally obtained toner is improved, and the toner exhibits particularly excellent stability against mechanical stress. Further, when the melting point of the block polyester is higher than the softening point of the amorphous polyester described later, for example, in the thermal spheroidization treatment described later, the non-crystalline polyester is obtained while maintaining the shape stability of the powder for toner production to some extent. The crystalline polyester can be sufficiently softened. As a result, the thermal sphering process can be performed efficiently, and the circularity of the finally obtained toner (toner particles) can be relatively easily increased.
[0099]
By the way, as described above, since the block polyester used in the present embodiment has a crystalline block with high crystallinity, it is used for a resin material having relatively low crystallinity (for example, an amorphous polyester or the like described later). In comparison, it has a so-called sharp melt property.
As an index representing the crystallinity, for example, the center value of the peak when the endothermic peak of the melting point is measured by differential scanning calorimetry (DSC) is T. _mp [° C], the shoulder peak value is T _ms When [° C.], ΔT = T _mp -T _ms (See FIG. 6). The smaller the ΔT value, the higher the crystallinity.
[0100]
The ΔT value of the block polyester is preferably at most 50 ° C, more preferably at most 20 ° C. T _mp [° C], T _ms The measurement conditions of [° C.] are not particularly limited. For example, after the temperature of a block polyester to be a sample is increased to 200 ° C. at a rate of temperature increase of 10 ° C./min, and further decreased at a rate of temperature decrease of 10 ° C./min. The temperature can be measured by raising the temperature at a rate of 10 ° C./min.
[0101]
Further, the block polyester has higher crystallinity than the amorphous polyester described below. Accordingly, the ΔT value of the amorphous polyester is ΔT _A [° C], the ΔT value of the block polyester is ΔT _B When [° C], ΔT _A > ΔT _B Satisfy the relationship. In particular, in the present embodiment, ΔT _A −ΔT _B > 10 is preferably satisfied. _A −ΔT _B More preferably, the relationship of> 30 is satisfied. By satisfying such a relationship, the above-described effects become more remarkable. However, when the crystallinity of the amorphous polyester is particularly low, T _mp Or T _ms May be difficult to measure (discriminating). In such a case, ΔT _A Is ∞ [° C].
[0102]
The block polyester has a heat of fusion E determined by measuring the endothermic peak of the melting point by differential scanning calorimetry. _f Is preferably 5 mJ / mg or more, and more preferably 15 mJ / mg or more. Heat of fusion E _f Is less than 5 mJ / mg, the above-mentioned effect due to having a crystalline block may not be sufficiently exerted. However, the heat of fusion does not include the calorific value of the endothermic peak at the glass transition point (see FIG. 6). The conditions for measuring the endothermic peak of the melting point are not particularly limited. For example, the temperature of a block polyester to be a sample was increased to 200 ° C. at a rate of 10 ° C./min, and further decreased at a rate of 10 ° C./min. Thereafter, a value measured when the temperature is raised at a temperature rising rate of 10 ° C./min can be determined as the heat of fusion.
[0103]
The block polyester is preferably a linear polymer (a polymer having no cross-linked structure). Linear polymers have a lower coefficient of friction than cross-linked polymers. Thereby, particularly excellent releasability is obtained, and the transfer efficiency of the toner is further improved.
In addition, the block polyester may have a block other than the above-described crystalline block and amorphous block.
[0104]
1-2. Amorphous polyester
Amorphous polyester has lower crystallinity than the above-mentioned block polyester.
Amorphous polyester is mainly composed of dispersibility of components (for example, a colorant, a wax, an antistatic agent and the like to be described later) constituting the toner, pulverizability of a kneaded material at the time of toner production, fixability of the toner. (Especially, low-temperature fixability), a component that contributes to improving functions such as transparency, mechanical properties (for example, elasticity and mechanical strength, etc.), chargeability, and moisture resistance. In other words, when the amorphous polyester as described in detail below is not contained in the toner, it is difficult to sufficiently exhibit the characteristics required for the toner as described above.
[0105]
Hereinafter, components constituting the amorphous polyester will be described.
The diol component constituting the amorphous polyester may be any diol component having two hydroxyl groups, and examples thereof include an aromatic diol having an aromatic ring structure and an aliphatic diol having no aromatic ring structure. . Examples of the aromatic diol include bisphenol A and an alkylene oxide adduct of bisphenol A, and examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, , 3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2 , 4-pentanediol, 3-methyl -1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, polyethylene glycol, Chain diols such as polypropylene glycol and polytetramethylene glycol, or 2,2-bis (4-hydroxycyclohexyl) propane, alkylene oxide adducts of 2,2-bis (4-hydroxycyclohexyl) propane, 1,4- And cyclic diols such as cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, and alkylene oxide adduct of hydrogenated bisphenol A.
[0106]
As the dicarboxylic acid component constituting the amorphous polyester, a divalent carboxylic acid or a derivative thereof (eg, acid anhydride, lower alkyl ester, etc.) can be used. For example, o-phthalic acid (phthalic acid) can be used. , Terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid and derivatives thereof (eg, anhydrides, lower alkyl esters, etc.) And the like.
[0107]
As described above, the dicarboxylic acid component constituting the amorphous polyester is not particularly limited, but it is preferable that at least a part thereof has a terephthalic acid skeleton, and at least 80 mol% of the dicarboxylic acid component has a terephthalic acid skeleton. More preferably, 90 mol% or more thereof has a terephthalic acid skeleton. As a result, the finally obtained toner has a particularly excellent balance of various properties required for the toner. However, the “dicarboxylic acid component” here refers to the dicarboxylic acid component when it is made into an amorphous polyester, and when adjusting the amorphous polyester, the dicarboxylic acid component itself or its acid anhydride is used. And derivatives such as lower alkyl esters.
[0108]
Further, it is preferable that 50 mol% or more (more preferably, 80 mol% or more) of the monomer component constituting the amorphous polyester is the same as the monomer component constituting the above-described amorphous block. That is, the amorphous polyester is preferably composed of the same monomer components as the amorphous block. Thereby, the compatibility between the amorphous polyester and the block polyester becomes particularly excellent. However, the “monomer component” here does not indicate a monomer used for producing an amorphous polyester or a block polyester, but indicates a monomer component contained in the amorphous polyester or the block polyester.
The amorphous polyester may contain a component other than the diol component and the dicarboxylic acid component (for example, a trivalent or higher valent alcohol component or a trivalent or higher carboxylic acid component). .
[0109]
The average molecular weight (weight average molecular weight) Mw of the amorphous polyester is not particularly limited. ³ ~ 4 × 10 ⁴ And preferably 8 × 10 ³ ~ 2.5 × 10 ⁴ Is more preferable. If the average molecular weight Mw is less than the lower limit, the mechanical strength of the finally obtained toner may be reduced, and sufficient durability (storability) may not be obtained. On the other hand, when the average molecular weight Mw is too small, cohesive failure tends to occur during fixing of the toner, and the offset resistance tends to decrease. On the other hand, when the average molecular weight Mw exceeds the above upper limit, grain boundary destruction is likely to occur at the time of fixing the toner, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.
[0110]
Glass transition point T of amorphous polyester _g Although it is not particularly limited, it is preferably 50 to 75 ° C, more preferably 55 to 70 ° C. When the glass transition point is less than the lower limit, the storage stability (heat resistance) of the toner is reduced, and depending on the use environment, fusion between toner particles may occur. On the other hand, when the glass transition point exceeds the upper limit, the low-temperature fixability and the transparency are reduced. On the other hand, if the glass transition point is too high, the effect of the thermal sphering treatment described later may not be sufficiently exerted. The glass transition point can be measured according to JIS K7121.
[0111]
Softening point T of amorphous polyester _1/2 Although it is not particularly limited, it is preferably from 90 to 160 ° C, more preferably from 100 to 150 ° C, even more preferably from 100 to 130 ° C. If the softening point is less than the lower limit, the storability of the toner may decrease, and sufficient durability may not be obtained. On the other hand, if the softening point is too low, cohesive failure tends to occur when fixing the toner, and the offset resistance tends to decrease. On the other hand, if the softening point exceeds the above upper limit, the grain boundary is likely to be broken at the time of fixing the toner, the wettability to a transfer material (recording medium) such as paper is reduced, and the amount of heat required for fixing is increased.
[0112]
Further, the softening point of the amorphous polyester is defined as T _1/2 (A) [° C.] _m (B), T _m (B)> (T _1/2 (A) +60) is preferably satisfied, and (T) _1/2 (A) +60) <T _m (B) <(T _1/2 It is more preferable to satisfy the relationship of (A) +150). By satisfying such a relationship, for example, the thermal sphering process described later can be performed more efficiently, and the circularity of the obtained toner (particles) can be further improved. Further, by satisfying the above relationship, the toner can exhibit excellent fixability in a wider temperature range.
[0113]
The softening point T _1/2 For example, using a flow tester, a sample amount: 1 g, a die hole diameter: 1 mm, a die length: 1 mm, a load: 20 kgf, a preheating time: 300 seconds, a measurement start temperature: 50 ° C., and a heating rate: 5 ° C./min. Can be obtained as a temperature at a point on the flow curve corresponding to h / 2 in the analysis flowchart as shown in FIG.
The amorphous polyester is preferably a linear polymer (a polymer having no cross-linked structure). Linear polymers have a lower coefficient of friction than cross-linked polymers. Thereby, particularly excellent releasability is obtained, and the transfer efficiency of the toner is further improved.
[0114]
As described above, by using the block polyester and the amorphous polyester in combination, it is possible to achieve both the features of the block polyester and the features of the amorphous polyester as described above. As a result, the finally obtained toner is resistant to mechanical stress (has sufficient physical stability) and can exhibit sufficient fixability (fixing strength) in a wide temperature range. It becomes.
[0115]
Such a synergistic effect cannot be obtained when only one of the block polyester and the amorphous polyester is used.
That is, when only the block polyester is used (when the amorphous polyester is not contained in the toner), the fixing property of the toner (particularly, the fixing property in a low temperature region) is reduced. Further, when only the block polyester is used (when the amorphous polyester is not contained in the toner), the functions such as the transparency of the toner are deteriorated, and each component constituting the toner (for example, as described later) Dispersibility of various colorants, waxes, antistatic agents, etc.) and the pulverizability of the kneaded material at the time of toner production also decrease.
[0116]
When only amorphous polyester is used (when no block polyester is contained in the toner), the finally obtained toner is weak in mechanical stress and has sufficient durability and storage stability. I can't. Further, when only amorphous polyester is used (when no block polyester is contained in the toner), a sharp melt property cannot be obtained, so that sufficient fixability (fixing strength) can be obtained in a wide temperature range (particularly a high temperature range). ), It is difficult to efficiently perform the thermal sphering process described later, and it is difficult to set the circularity of the finally obtained toner particles to an appropriate value.
[0117]
By the way, a polyester having high crystallinity (hereinafter, referred to as “crystalline polyester”) generally has a stable molecular arrangement structure, so that even if it is not a block polyester as described above, the strength as a toner is improved. It is possible to make it resistant to mechanical stress. However, crystalline polyesters other than the above-mentioned block polyester have poor compatibility with the amorphous polyester, and when used in combination with the amorphous polyester, phase separation tends to occur. Therefore, when the crystalline polyester other than the block polyester and the amorphous polyester are used in combination without using the block polyester, the synergistic effect of using the block polyester and the amorphous polyester as described above is used. No effect.
[0118]
The mixing ratio between the block polyester and the amorphous polyester is preferably from 5:95 to 45:55 by weight, more preferably from 10:90 to 30:70. If the blending ratio of the block polyester is too low, it may be difficult to sufficiently improve the offset resistance of the toner. On the other hand, if the compounding ratio of the amorphous polyester is too low, sufficient low-temperature fixability and transparency may not be obtained. If the compounding ratio of the amorphous polyester is too low, for example, in the pulverizing step of the toner production method described later, it becomes difficult to pulverize the kneaded material 7 efficiently and uniformly.
[0119]
Further, the resin (binder resin) may include a component (third resin component) other than the above-described block polyester and amorphous polyester.
As the resin component (third resin component) other than the block polyester and the amorphous polyester, for example, polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, Styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene Styrene-based resins such as acrylate-methacrylate copolymer, styrene-α-methyl methacrylate copolymer, styrene-acrylonitrile-acrylate copolymer, and styrene-vinyl methyl ether copolymer; Or containing a styrene substituent Homopolymer or copolymer, polyester resin (different from the above-mentioned block polyester and amorphous polyester), epoxy resin, urethane-modified epoxy resin, silicone-modified epoxy resin, vinyl chloride resin, rosin-modified maleic resin, Phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, etc. And these may be used alone or in combination of two or more.
[0120]
The content of the resin in the raw material 5 is not particularly limited, but is preferably from 50 to 98 wt%, and more preferably from 85 to 97 wt%. When the content of the resin is less than the lower limit, the function (for example, good fixability in a wide temperature range) of the resin may not be sufficiently exhibited in the finally obtained toner. On the other hand, when the content of the resin exceeds the above upper limit, the content of components other than the resin such as the colorant relatively decreases, and it is difficult to sufficiently exhibit the toner characteristics such as color development.
[0121]
2. Colorant
As the colorant, for example, a pigment, a dye, or the like can be used. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, graphite, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, navy blue, cobalt blue, aluminum Ribble Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chromium Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (CI No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modant Red 30, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modant Blue 7, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials including magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination.
[0122]
The content of the coloring agent in the raw material 5 is not particularly limited, but is preferably 1 to 10 wt%, more preferably 3 to 8 wt%. When the content of the colorant is less than the lower limit, it may be difficult to form a visible image having a sufficient density depending on the type of the colorant. On the other hand, when the content of the coloring agent exceeds the above upper limit, the content of the resin relatively decreases, and the fixability to a transfer material (recording medium) such as paper at a required color density decreases.
[0123]
3. wax
In addition, the raw material 5 used for the production of the toner may contain a wax, if necessary.
By including the wax, for example, the releasability of the toner particles can be improved.
[0124]
Examples of the wax include hydrocarbon waxes such as ozokerite, celsin, paraffin wax, micro wax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, and palmitic acid. Methyl, methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, ester wax such as fatty acid ester, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax Amide wax such as olefin wax such as 12-hydroxystearic amide, stearic amide, phthalic anhydride, lauro , Ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.
[0125]
Among the above-mentioned materials, particularly when an ester wax (for example, carnauba wax or rice wax) is used, the following effects can be obtained.
The ester wax has an ester structure in the molecule similarly to the polyester resin described above, and is excellent in compatibility with the polyester resin. Further, as described above, the polyester resin has excellent compatibility with the resin as the main component. For this reason, generation and coarsening of free wax in the finally obtained toner particles can be prevented (fine dispersion and microphase separation of the wax in the toner can be easily achieved). As a result, the finally obtained toner has particularly excellent releasability from the fixing roller.
[0126]
Melting point T of wax _m Although it does not specifically limit, It is preferable that it is 30-160 degreeC, and it is more preferable that it is 50-100 degreeC. Note that, for example, by differential scanning calorimetry (DSC), the temperature was raised to 200 ° C. at a rate of 10 ° C./min, and further decreased at a rate of 10 ° C./min. The melting point T _m And the heat of fusion.
[0127]
Further, for example, in addition to the above-described wax, a low-melting polyester (hereinafter also referred to as “low-melting polyester”) can be used as a component capable of imparting a wax effect. The low melting point is, for example, a melting point T _m Is preferably about 70 to 90 ° C. Further, the weight average molecular weight Mw of the low melting point polyester is preferably about 3500 to 6500. The low-melting polyester is preferably a polymer of an aliphatic monomer. When the low-melting polyester satisfies such conditions (at least one, and preferably two or more), the compatibility with the polyester resin described above becomes particularly excellent, and the durability of the toner is improved. Can be provided without releasing the toner. Further, since the melting point is relatively low, low-temperature fixability can be improved.
[0128]
4. Other ingredients
Further, the raw material 5 may contain components other than the resin, the colorant, and the wax. Examples of such a component include a charge control agent, a dispersant, and a magnetic powder.
Examples of the charge control agent include a metal salt of benzoic acid, a metal salt of salicylic acid, a metal salt of alkyl salicylic acid, a metal salt of catechol, a metal-containing bisazo dye, a nigrosine dye, a tetraphenylborate derivative, a quaternary ammonium salt, Examples thereof include an alkylpyridinium salt, a chlorinated polyester, and nitrophenic acid.
[0129]
Examples of the dispersant include metal soaps, inorganic metal salts, organic metal salts, and polyethylene glycol.
Examples of the metal soap include metal tristearate (eg, aluminum salt, etc.), metal distearate (eg, aluminum salt, barium salt, etc.), metal stearate (eg, calcium salt, lead salt, zinc salt, etc.) ), Metal linolenate (eg, cobalt salt, manganese salt, lead salt, zinc salt, etc.), metal octanoate (eg, aluminum salt, calcium salt, cobalt salt, etc.), metal oleate (eg, calcium salt) , Cobalt salts, etc.), metal palmitates (eg, zinc salts, etc.), metal naphthenates (eg, calcium salts, cobalt salts, manganese salts, lead salts, zinc salts, etc.), metal resinate salts (eg, calcium Salt, cobalt salt, manganese lead salt, zinc salt and the like).
[0130]
Examples of the inorganic metal salt and the organic metal salt include, as a cationic component, a cation of an element selected from the group consisting of metals of Groups IA, IIA, and IIIA of the periodic table; Examples of the sexual component include salts containing an anion selected from the group consisting of halogen, carbonate, acetate, sulfate, borate, nitrate, and phosphate.
[0131]
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, metal oxides such as magnesium oxide, and Fe, Co, and Ni. Examples thereof include those made of a magnetic material including a magnetic metal.
As the additive, for example, zinc stearate, zinc oxide, cerium oxide, or the like may be used in addition to the above-described materials.
[0132]
[Kneading process]
The raw material 5 as described above is kneaded using a kneader 1 as shown in FIG.
The raw material 5 to be kneaded is preferably one in which the above-described components are mixed in advance.
In the present embodiment, a configuration using a twin-screw kneading extruder as the kneading machine will be described.
[0133]
The kneading machine 1 includes a process section 2 for mixing and kneading the raw material 5, a head section 3 for forming the kneaded raw material (kneaded material 7) into a predetermined cross-sectional shape, and extruding the raw material 5 in the processing section 2. And a feeder 4 for supplying.
The process unit 2 includes a barrel 21, a screw 22 and a screw 23 inserted in the barrel 21, and a fixing member 24 for fixing the head unit 3 to a tip of the barrel 21.
In the process section 2, a shearing force is applied to the raw material 5 supplied from the feeder 4 by rotation of the screw 22 and the screw 23, so that the uniform kneaded material 7, especially the block polyester and the amorphous polyester are sufficiently mixed. Is obtained.
[0134]
The total length of the process section 2 is preferably 50 to 300 cm, and more preferably 100 to 250 cm. If the total length of the process section 2 is less than the lower limit, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, if the total length of the process section 2 exceeds the upper limit, the raw material 5 is likely to be denatured by heat depending on the temperature in the process section 2, the rotation speed of the screws 22 and the screw 23, and the like. It may be difficult to sufficiently control the physical properties of the material.
[0135]
Further, the processing section 2 has a first area 25 having a predetermined length in the longitudinal direction, and a second area 26 provided on the head section 3 side with respect to the first area 25. That is, the raw material 5 is sent to the second region 26 after passing through the first region 25.
The internal temperature of the first area 25 is set higher than that of the second area 26. That is, in other words, the temperature of the raw material 5 conveyed inside the process unit 2 when passing through the first region 25 is higher than the temperature when passing through the second region 26.
[0136]
Thus, by kneading the raw material 5 at a relatively high temperature in the first region 25, the block polyester and the amorphous polyester can be sufficiently compatibilized.
Raw material temperature in first region 25 (internal temperature of first region 25) T ₁ [° C] is the melting point of the block polyester _m (B) When [° C.], T _m (B) ≦ T ₁ Satisfies the relationship of (T _m (B) + 10 ° C) ≦ T ₁ ≤ (T _m (B) + 60 ° C.) is more preferable. Raw material temperature T ₁ But T _m (B) When the temperature is lower than [° C.], it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester.
[0137]
Raw material temperature T in first region 25 ₁ Although the specific value varies depending on the composition of the resin and the like, it is preferably 190 to 300 ° C, more preferably 200 to 250 ° C.
Further, in the first region 25, the raw material temperature T ₁ May be uniform or different depending on the site. In the latter case, the maximum temperature of the raw material 5 in the first region 25 is preferably higher than the lower limit, and the minimum temperature and the maximum temperature of the raw material 5 in the first region 25 are within the above range. More preferably, there is.
[0138]
The residence time (time required for passage) of the raw material 5 in the first region 25 is preferably 0.5 to 12 minutes, and more preferably 0.5 to 7 minutes. If the residence time in the first region 25 is less than the lower limit, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, if the residence time in the first region 25 exceeds the upper limit, the production efficiency decreases, and depending on the temperature in the process unit 2, the rotation speed of the screws 22 and 23, etc. 5 easily occurs, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0139]
Further, the length of the first region 25 is preferably from 10 to 200 cm, and more preferably from 20 to 150 cm. If the length of the first region 25 is less than the lower limit, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester. On the other hand, if the length of the first region 25 exceeds the upper limit value, the production efficiency is reduced, and the temperature of the raw material 5 due to heat depends on the temperature in the process unit 2 and the rotation speed of the screws 22 and 23. May easily occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0140]
By the way, in the first region 25, the block polyester and the amorphous polyester are sufficiently compatibilized by kneading at a relatively high temperature. However, since the block polyester and the amorphous polyester are resins having greatly different molecular structures from each other, even when the block polyester and the amorphous polyester are sufficiently compatible, the cooling of the kneaded material is not possible. Depending on conditions and the like, the block polyester and the amorphous polyester may cause phase separation.
[0141]
Therefore, in the present embodiment, the second region 26 is provided and the kneading is performed at a relatively lower temperature than that of the first region 25, as in the illustrated configuration. Thereby, poor dispersion of each component of the kneaded material 7 and occurrence of phase separation can be effectively prevented. When the raw material 5 contains a wax (particularly a wax having a low compatibility with the resin), the wax in the kneaded material 7 can be prevented from being coarsened, and the wax is finely divided into an appropriate particle size. Can be dispersed. As a result, in the kneaded material 7 obtained, a decrease in pulverizability can be effectively suppressed, and in the finally obtained toner, a decrease in transparency and durability, occurrence of offset, and the like can be suppressed. can do. In addition, since the respective constituent components in the kneaded material 7 are uniformly dispersed in the toner, the dispersion of the characteristics among the respective particles of the toner is small, and the characteristics as a whole can be excellent. . Therefore, the effect of each component can be sufficiently exhibited.
[0142]
Further, in particular, by providing the first region 25 and the second region 26 as described above, the crystallization of the block polyester proceeds efficiently in the second region 26 while sufficiently preventing phase separation. Therefore, the finally obtained toner is resistant to mechanical stress.
Raw material temperature in second region 26 (internal temperature of second region 26) T ₂ [° C] is the softening point of amorphous polyester as T _1/2 (A) When [° C.], (T _1/2 (A) -20) ≦ T ₂ ≤ (T _1/2 (A) +20) is preferably satisfied, and (T _1/2 (A) -10) ≦ T ₂ ≤ ( _{T1 / 2} It is more preferable to satisfy the relationship of (A) +10). Raw material temperature T ₂ However, if it is less than the lower limit, phase separation or the like in the kneaded material 7 is likely to occur, and the fluidity of the block polyester and the amorphous polyester is reduced, which may lower the productivity of the toner. On the other hand, the raw material temperature T ₂ However, if the upper limit is exceeded, the above-described effect of providing the second region 26 may not be sufficiently obtained.
[0143]
Raw material temperature T in second region 26 ₂ The specific value varies depending on the composition of the resin, but is preferably from 80 to 150C, more preferably from 90 to 140C.
[0144]
Further, in the second region 26, the raw material temperature T ₂ May be uniform or different depending on the site. In the latter case, the minimum temperature of the raw material 5 in the first region 25 is preferably within the above range.
In the illustrated configuration, the temperature of the raw material is T between the first region 25 and the second region 26. ₁ To T ₂ A temperature transition region 28 that transitions to is provided.
[0145]
The residence time of the raw material 5 in the second region 26 is preferably 0.5 to 12 minutes, more preferably 1 to 7 minutes. If the residence time in the second region 26 is less than the lower limit, the above-described effect due to the provision of the second region 26 may not be sufficiently obtained. On the other hand, if the residence time in the second region 26 exceeds the upper limit, the production efficiency is reduced, and depending on the temperature in the process unit 2, the rotation speed of the screws 22 and 23, etc. 5 easily occurs, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0146]
Further, the length of the second region 26 is preferably 20 to 200 cm, and more preferably 40 to 150 cm. If the length of the second region 26 is less than the lower limit, the above-described effect of providing the second region 26 may not be sufficiently obtained. On the other hand, if the length of the second region 26 exceeds the upper limit, the production efficiency is reduced, and the temperature of the raw material 5 due to heat depends on the temperature in the process unit 2 and the rotation speed of the screws 22 and 23. May easily occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.
[0147]
Also, the raw material temperature T in the first region 25 ₁ And the raw material temperature T in the second region 26 ₂ Is (T ₁ -T ₂ ) ≧ 80 [° C.], and preferably 80 ≦ (T ₁ -T ₂ It is more preferable to satisfy the relationship: ≦ 160 [° C.]. (T ₁ -T ₂ ) Is less than the lower limit, it may be difficult to sufficiently prevent phase separation in the cooling step described below.
[0148]
The rotation speed of the screw 22 and the screw 23 varies depending on the mixing ratio of the block polyester and the amorphous polyester, the composition, the molecular weight, and the like, but is preferably 50 to 600 rpm. If the rotation speed of the screw 22 and the screw 23 is less than the lower limit, for example, in the first region 25, it may be difficult to sufficiently compatibilize the block polyester and the amorphous polyester, In the second region 26, it may be difficult to sufficiently prevent phase separation.
On the other hand, if the rotation speed of the screws 22 and 23 exceeds the upper limit, the polyester molecules may be cut due to shearing, and the properties of the resin may deteriorate.
[0149]
In the illustrated configuration, a third region 27 different from the first region 25 and the second region 26 is provided on the feeder 4 side of the first region 25 (opposite to the second region 26). Have been. As described above, the process unit 2 may have a region other than the first region 25 and the second region 26.
Raw material temperature T in third region 27 ₃ [° C.] is the raw material temperature T in the second region 26. ₂ Between (T ₂ −40) ≦ T ₃ ≤ (T ₂ +40), and (T ₂ −20) ≦ T ₃ ≤ (T ₂ +20) is more preferably satisfied. Raw material temperature T ₃ However, if it is less than the lower limit, the resin is hardly melted, and the kneading torque may be too high. On the other hand, the raw material temperature T ₃ However, if the upper limit is exceeded, the temperature of the raw material input port becomes high, the feeder 4 is also heated, and the resin may be melted and fixed to the feeder 4 in some cases.
[0150]
In the configuration shown in the drawing, the raw material temperature is T between the third region 27 and the first region 25. ₃ To T ₁ A temperature transition region 29 that transitions to is provided.
In the illustrated configuration, the configuration in which the first region 25, the second region 26, and the third region 27 are provided has been described, but the configuration in which other regions are provided is not provided. You may. For example, such a region may be between the first region 25 and the second region 26, or may be closer to the head unit 3 than the second region 26.
[0151]
[Extrusion process]
The kneaded material 7 kneaded in the process unit 2 is pushed out of the kneader 1 via the head unit 3 by the rotation of the screw 22 and the screw 23.
The head unit 3 has an internal space 31 into which the kneaded material 7 is sent from the process unit 2 and an extrusion port 32 through which the kneaded material 7 is extruded.
[0152]
Temperature of kneaded material 7 in internal space 31 (at least temperature near extrusion port 32) T ₄ [° C] is T ₂ The temperature is preferably higher by about 10 ° C. Temperature T of kneaded material 7 ₄ However, at such a temperature, the kneaded material 7 does not solidify in the internal space 31 and is easily extruded from the extrusion port 32.
In the illustrated configuration, the internal space 31 has a cross-sectional area gradually decreasing portion 33 whose cross-sectional area gradually decreases toward the extrusion port 32.
[0153]
By having such a cross-sectional area gradually decreasing portion 33, the extrusion amount of the kneaded material 7 extruded from the extrusion port 32 is stabilized, and the cooling rate of the kneaded material 7 in a cooling step described later is stabilized. As a result, the toner produced by using the toner has small variations in characteristics among the toner particles, and has excellent characteristics as a whole.
[0154]
[Cooling step]
The softened kneaded material 7 extruded from the extrusion port 32 of the head portion 3 is cooled by the cooler 6 and solidified.
The cooler 6 has rolls 61, 62, 63, 64 and belts 65, 66.
The belt 65 is wound around a roll 61 and a roll 62. Similarly, the belt 66 is wound around the roll 63 and the roll 64.
[0155]
The rolls 61, 62, 63, and 64 rotate in directions indicated by e, f, g, and h in the figure, respectively, around the rotation shafts 611, 621, 631, and 641. As a result, the kneaded material 7 extruded from the extrusion port 32 of the kneader 1 is introduced between the belt 65 and the belt 66. The kneaded material 7 introduced between the belt 65 and the belt 66 is cooled while being formed into a plate having a substantially uniform thickness. The cooled kneaded material 7 is discharged from the discharge unit 67. The belts 65 and 66 are cooled by a method such as water cooling or air cooling. When such a belt-type cooler is used, the contact time between the kneaded material extruded from the kneader and the cooling body (belt) can be lengthened, and the efficiency of cooling the kneaded material is particularly excellent. It can be.
[0156]
By the way, in the kneading step, the shearing force is applied to the raw material 5, so that phase separation or the like is sufficiently prevented. Otherwise, phase separation or the like may occur again. Therefore, it is preferable to cool the kneaded material 7 obtained as described above as soon as possible. Specifically, the cooling rate of the kneaded material 7 (for example, the cooling rate when the kneaded material 7 is cooled to about 60 ° C.) is preferably −3 ° C./sec or more, and is −5 to −100 ° C./second. More preferably, it is seconds. The time required from the end of the kneading step (when the shearing force is no longer applied) to the completion of the cooling step (for example, the time required to cool the temperature of the kneaded material 7 to 60 ° C. or less) is 20 seconds. The time is preferably the following, more preferably 3 to 12 seconds.
[0157]
In the present embodiment, a configuration in which a continuous twin-screw kneading extruder is used as the kneader has been described, but the kneader used for kneading the raw materials is not limited to this. For kneading the raw materials, for example, various kneaders such as a kneader or a batch type triaxial roll, a continuous biaxial roll, a wheel mixer, a blade type mixer, or the like can be used.
In the illustrated configuration, the kneader having a configuration having two screws has been described, but the number of screws may be one, or three or more.
[0158]
Further, in the present embodiment, the configuration using one kneader has been described, but kneading may be performed using two kneaders. In this case, the process section of one kneader may be used as the first area 25, and the process section of the other kneader may be used as the second area 26.
Further, in the present embodiment, a configuration using a belt-type cooling device has been described. However, for example, a roll-type (cooling roll-type) cooling device may be used. Further, the cooling of the kneaded material extruded from the extrusion port 32 of the kneader is not limited to the one using the above-described cooler, and may be, for example, air cooling or the like.
[0159]
[Granulation process]
By granulating the kneaded material 7 having undergone the cooling step as described above, a powder for toner production is obtained.
In the present embodiment, the granulating step has a pulverizing step and a thermal spheronizing step as described below.
Note that the thermal spheroidizing step is not necessarily performed.
[0160]
(Pulverizing process)
First, the kneaded material 7 having undergone the cooling step as described above is pulverized.
The method of pulverization is not particularly limited, and the pulverization can be performed using various pulverizers and crushers such as a ball mill, a vibration mill, a jet mill, and a pin mill.
The pulverizing step may be performed a plurality of times (for example, two steps of a coarse pulverizing step and a fine pulverizing step).
Further, after such a pulverizing step, if necessary, a treatment such as a classification treatment may be performed.
For the classification process, for example, a sieve, an airflow classifier, or the like can be used.
[0161]
[Thermospheric process (thermospheric process)]
Next, the powder (powder for toner production) obtained in the above-mentioned pulverizing step is subjected to a thermal sphering treatment for spheroidizing by heating.
By performing such a thermal sphering treatment, relatively large irregularities on the surface of the powder for toner production are removed, and the degree of circularity is relatively high. As a result, the toner obtained finally has a small difference in charging characteristics between the individual toner powders, thereby improving the developability on the photoconductor and adhering the toner to the photoconductor (filming). ) Is more effectively prevented, and the transfer efficiency of the toner is further improved.
[0162]
In particular, in the present embodiment, since a block polyester having a crystalline block is included, it is necessary to sufficiently soften the amorphous polyester while securing the shape stability of the powder for toner production to some extent during the thermal sphering treatment. Can be. Therefore, as compared with the case where a raw material containing no block polyester is used, the thermal sphering treatment can be performed efficiently, and the circularity of the finally obtained toner (toner particles) is relatively high. Things. As a result, the effect of the above-described thermal sphering process can be more effectively exerted.
[0163]
The thermal sphering treatment can be performed by injecting the toner production powder obtained in the pulverization step under a heated atmosphere using, for example, compressed air. The ambient temperature at this time is preferably from 210 to 320 ° C, more preferably from 230 to 300 ° C. If the ambient temperature is lower than the lower limit, it may be difficult to sufficiently increase the circularity. On the other hand, when the ambient temperature exceeds the upper limit, thermal decomposition, oxidative degradation, and the like of the material, aggregation, phase separation, and the like are likely to occur, and the function of the finally obtained toner may be reduced.
[0164]
Further, the melting point of the block polyester is set to T _m (B) [° C.], the softening point of the amorphous polyester is T _1/2 (A) When [° C.] is set, the ambient temperature T during the thermal sphering process _S [° C] is (T _1/2 (A) +120) ≦ T _S ≤ (T _m (B) +90), and (T _1/2 (A) +140) ≦ T _S ≤ (T _m It is more preferable to satisfy the relationship of (B) +70). By performing the thermal sphering treatment at such an ambient temperature Ts, the degree of circularity of the obtained toner particles can be reduced while sufficiently preventing the occurrence of thermal decomposition, oxidative deterioration, and the like, aggregation, and phase separation of the material. Can be relatively high.
[0165]
As described above, a toner production powder can be obtained.
Note that such a thermal sphering process may be performed in a liquid.
Further, after such a thermal sphering step, if necessary, a treatment such as a classification treatment may be performed.
For the classification process, for example, a sieve, an airflow classifier, or the like can be used.
[0166]
<External additives>
Next, the external additive will be described.
Examples of the external additive include metals such as titanium oxide, silica (positive charge silica, negative charge silica, etc.), aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, zinc oxide, alumina, magnetite and the like. Oxides, nitrides such as silicon nitride, carbides such as silicon carbide, fine particles made of inorganic materials such as calcium sulfate, calcium carbonate, and metal salts such as aliphatic metal salts, acrylic resin, fluorine resin, polystyrene resin, polyester Examples thereof include resins and organic materials such as aliphatic metal salts (for example, magnesium stearate).
[0167]
Among the above external additives, examples of titanium oxide that can be used as an external additive include rutile-type titanium oxide, anatase-type titanium oxide, and rutile-anatase-type titanium oxide.
The rutile-anatase type titanium oxide has rutile-type titanium oxide (titanium dioxide) and anatase-type titanium oxide (titanium dioxide) in the same particle. That is, the rutile-anatase type titanium oxide has a mixed crystal type titanium oxide (titanium dioxide) of a rutile type crystal and an anatase type crystal.
[0168]
Rutile-type titanium oxide generally has a property of easily forming a spindle-shaped crystal. Moreover, anatase type titanium oxide has a property that it easily precipitates fine crystals and has an excellent affinity with a silane coupling agent used for a hydrophobic treatment or the like.
And, since rutile-anatase type titanium oxide has a mixed crystal type titanium oxide of rutile type crystal and anatase type crystal, advantages of rutile type titanium oxide and advantages of anatase type titanium oxide It has both. That is, in rutile-anatase type titanium oxide, fine anatase-type crystals are mixed between the rutile-type crystals (inside the rutile-type crystal), and as a whole, have a substantially spindle shape, so that the toner It becomes difficult to be buried in the mother particles, and since the rutile-anatase type titanium oxide as a whole has an excellent affinity with a silane coupling agent, etc., it is uniform on the surface of the rutile-anatase type titanium oxide powder. A stable hydrophobic film (silane coupling film) is easily formed. Therefore, by containing the rutile-anatase type titanium oxide, the obtained toner has a uniform charge distribution (sharp charge distribution of toner particles), stable charge characteristics, environmental characteristics (especially moisture resistance), and fluidity. It has excellent properties, such as anti-caking properties.
[0169]
In particular, the rutile-anatase type titanium oxide exhibits the following synergistic effects when used in combination with the polyester resin as described above.
That is, as described above, since the polyester-based resin contains a block polyester having a crystalline block with high crystallinity, the polyester resin mainly has a predetermined size of crystal formed by the crystalline block in the toner particles. It can be. By having such crystals, the rutile-anatase type titanium oxide is less likely to be buried in the base particles of the toner. That is, by containing a hard component such as the crystal, the rutile-anatase type titanium oxide is securely carried (attached) to the vicinity of the surface of the toner base particles. Thereby, the function of the rutile-anatase type titanium oxide (particularly, effects such as excellent fluidity and chargeability) can be sufficiently exhibited. As described above, when used in combination with the above-described polyester-based resin, the function of the rutile-anatase type titanium oxide can be sufficiently exhibited, so that the amount of the external additive used can be suppressed. As a result, it is possible to effectively prevent inconveniences caused by adding a large amount of the external additive (for example, a decrease in fixability to a transfer material (recording medium) such as paper).
[0170]
The ratio of rutile-type titanium oxide to anatase-type titanium oxide in rutile-anatase-type titanium oxide is not particularly limited, but is preferably 5:95 to 95: 5 by weight, and 50:50. More preferably, it is 90:10. By using such rutile-anatase-type titanium oxide, the effect of using the above-described rutile-anatase-type titanium oxide becomes more remarkable.
[0171]
The rutile-anatase type titanium oxide preferably absorbs light in a wavelength region of 300 to 350 nm. As a result, the toner is particularly excellent in light fastness (in particular, light fastness after fixing to a recording medium).
Although the shape of the rutile-anatase type titanium oxide used in the present embodiment is not particularly limited, it is generally substantially spindle-shaped.
[0172]
When the rutile anatase type titanium oxide has a substantially spindle shape, the average major axis diameter is preferably from 10 to 100 nm, more preferably from 20 to 50 nm. When the average major axis diameter is in such a range, the rutile-anatase type titanium oxide can sufficiently exhibit the above-described function, and is hardly buried in the base particles of the toner, and It is difficult to release. As a result, the stability of the toner against mechanical stress is further improved.
[0173]
The content of rutile-anatase type titanium oxide in the toner is not particularly limited, but is preferably 0.1 to 2.0% by weight, and more preferably 0.5 to 1.0% by weight. If the content of rutile anatase type titanium oxide is less than the lower limit, the effect of using rutile anatase type titanium oxide as described above may not be sufficiently exerted. On the other hand, when the content of the rutile-anatase type titanium oxide exceeds the upper limit, the fixability of the toner tends to decrease.
[0174]
Such rutile-anatase-type titanium oxide may be prepared by any method, and for example, can be obtained by calcining anatase-type titanium oxide. By using such a method, the ratio of rutile-type titanium oxide to anatase-type titanium oxide in rutile-anatase-type titanium oxide can be relatively easily and reliably controlled. When rutile-anatase type titanium oxide is obtained by such a method, the firing temperature is preferably about 700 to 1000 ° C. By setting the firing temperature to a value in such a range, it is possible to more easily and reliably control the abundance ratio of rutile-type titanium oxide and anatase-type titanium oxide in rutile-anatase-type titanium oxide. Become.
[0175]
The rutile-anatase type titanium oxide is preferably subjected to a hydrophobic treatment. By performing the hydrophobizing treatment, an effect is obtained that charging is not greatly affected by humidity. As the hydrophobizing treatment, for example, HMDS, a silane coupling agent (for example, one having a functional group such as an amino group), a titanate coupling agent, a fluorine-containing silane coupling agent, a silicone oil, or the like is used. Surface treatment of powder (particles) of rutile-anatase type titanium oxide.
[0176]
Further, among the external additives described above, examples of the silica that can be used as the external additive include positively chargeable silica and negatively chargeable silica. Positively chargeable silica can be obtained, for example, by subjecting negatively chargeable silica to a surface treatment with a silane coupling agent having a functional group such as an amino group.
When negatively chargeable silica is used as the external additive, the charge amount (absolute value) of the toner particles can be increased. As a result, a stable negatively charged toner can be obtained, and the effect that toner control of the image forming apparatus becomes easy can be obtained.
[0177]
In addition, when negatively chargeable silica is used in combination with the above-described rutile-anatase type titanium oxide, a particularly excellent effect is obtained. That is, by using negatively chargeable silica and rutile anatase type titanium oxide in combination, the fluidity and environmental characteristics (particularly, moisture resistance) of the toner can be further enhanced, and more stable triboelectric chargeability can be exhibited. , So-called fogging can be more effectively prevented. Further, by using a combination of negatively chargeable silica and rutile anatase type titanium oxide, the obtained toner can have a larger charge amount (absolute value) and a sharper charge distribution.
[0178]
The average major axis diameter of the roughly spindle-shaped rutile-anatase type titanium oxide is represented by D ₁ [Nm], and the average particle diameter of the negatively chargeable silica is D ₂ [Nm], 0.2 ≦ D ₁ / D ₂ It is preferable to satisfy the relationship of ≦ 15, and 0.4 ≦ D ₁ / D ₂ It is more preferable to satisfy the relationship of ≦ 5. By satisfying such a relationship, the effect of using the negatively chargeable silica and the rutile anatase type titanium oxide together becomes more remarkable. In the present specification, the “average particle size” refers to a volume-based average particle size.
[0179]
When positively chargeable silica is used as the external additive, for example, the positively chargeable silica can function as a microcarrier, and the chargeability of the toner particles themselves can be further improved. In particular, by using the positively chargeable silica and the above-described rutile-anatase type titanium oxide in combination, the obtained toner can have a large charge amount (absolute value) and a sharper charge distribution. .
When it contains positively chargeable silica, its average particle size is preferably from 30 to 100 nm, more preferably from 40 to 50 nm. When the average particle diameter of the positively chargeable silica is in such a range, the above-described effect becomes more remarkable.
As the external additive, HMDS, a silane-based coupling agent (for example, one having a functional group such as an amino group), a titanate-based coupling agent on the surface of the fine particles composed of the above-described materials may be used. Alternatively, a material that has been surface-treated with a fluorine-containing silane coupling agent, silicone oil, or the like may be used.
[0180]
<Toner>
The toner of the present invention is obtained by mixing the above-described powder for toner production and an external additive using the above-described mixing apparatus of the present invention.
As described above, in the toner of the present invention, the incorporation of free and aggregated external additives is suitably prevented. Further, the external additive attached to the toner base particles (toner production powder) is in a state where it is hard to be released from the toner base particles. Therefore, the toner of the present invention can be suitably used for good image formation.
[0181]
In particular, in a toner obtained by the above-described apparatus and method, a liquid lubricant is externally added in a mist form. Thereby, the offset of the toner is suitably prevented. Further, the toner of the present invention has tackiness prevented, improved fluidity, and reduced blocking during transportation and stress in the image forming apparatus.
In the toner of the present invention, the ratio of the external additives that are free from the toner base particles (the ratio of those that are present as free external additives) is preferably 2 wt% or less, and more preferably 1 wt% or less. Is more preferred. As described above, when the ratio of the free external additive is sufficiently low, it is possible to more suitably prevent the above-described adverse effects caused by the free external additive.
[0182]
Further, the content of the external additive in the toner of the present invention is preferably 0.5 to 5% by weight, and more preferably 1 to 3% by weight. When the content of the external additive is in such a range, the function of the external additive is improved while sufficiently preventing the adverse effect of the external additive liberated from the toner base particles (toner production powder). It can be used effectively.
[0183]
In the toner (toner particles) of the present invention, the coverage of the external additive (the ratio of the surface area of the toner particles to the area covered by the external additive, and a sphere equivalent to the average particle size of the external additive is defined as (Calculated coverage when a sphere equivalent to a diameter is covered by 6-way close packing) is preferably 100 to 300%, more preferably 120 to 220%. If the coverage of the external additive is less than the lower limit, the effect of the external additive as described above may not be sufficiently exerted. On the other hand, when the coverage of the external additive exceeds the upper limit, the fixing property of the toner tends to decrease.
[0184]
The toner (toner particles) obtained as described above preferably has an average circularity R represented by the following formula (I) of 0.91 to 0.98, and more preferably 0.93 to 0.98. Is more preferred. If the average circularity R is less than 0.91, it is difficult to sufficiently reduce the difference in charging characteristics between individual toner particles, and the developability on the photoreceptor tends to decrease. On the other hand, if the average circularity R is too small, the adhesion (filming) of the toner on the photoreceptor is likely to occur, and the transfer efficiency of the toner may decrease. On the other hand, if the average circularity R exceeds 0.98, transfer efficiency and mechanical strength increase, but there is a problem that granulation (joining of particles) is promoted to increase the average particle diameter. On the other hand, when the average circularity R exceeds 0.98, it becomes difficult to remove, for example, toner adhered to the photoreceptor or the like by cleaning.
R = L ₀ / L ₁ ... (I)
(However, in the formula, L ₁ [Μm] is the perimeter of the projected image of the toner particles to be measured, L ₀ [Μm] represents the circumference of a perfect circle (complete geometric circle) having an area equal to the area of the projected image of the toner particles to be measured. )
[0185]
The average particle size of the toner is preferably 3 to 12 μm, more preferably 5 to 10 μm. When the average particle size of the toner is less than the lower limit, fusion and the like between toner particles easily occur. On the other hand, when the average particle size of the toner exceeds the upper limit, the resolution of the printed matter tends to decrease.
Further, the content of the resin in the toner is preferably from 50 to 98 wt%, and more preferably from 85 to 97 wt%. If the content of the resin is less than the above lower limit, the effect of the function of the resin (for example, good fixability in a wide temperature range) may not be sufficiently obtained. On the other hand, when the content of the resin exceeds the above upper limit, the content of components such as a colorant is relatively reduced, and it may be difficult to exhibit characteristics such as color developing properties.
[0186]
When wax is contained in the toner, the content thereof is not particularly limited, but is preferably 5% by weight or less, more preferably 3% by weight or less, and is preferably 0.5 to 3% by weight. More preferred. If the content of the wax is too large, the wax is liberated and coarsened, and the wax exudes to the toner surface, etc., and the toner transfer efficiency may become difficult to sufficiently increase.
[0187]
The acid value as a physical property of a toner is one of the factors that influence the environmental characteristics (particularly, moisture resistance) of the toner. The acid value of the toner is preferably 8 KOH mg / g or less, more preferably 1 KOH mg / g or less. When the acid value of the toner is 8 KOHmg / g or less, the environmental characteristics (particularly, moisture resistance) of the toner become particularly excellent.
When this toner is used in a fixing device having a nip portion as described later, the amount of change in the relaxation modulus G (t) in the passage time Δt [second] of the toner particles is 500 [ Pa] or less, and more preferably 100 [Pa] or less. By satisfying such conditions, inconveniences such as offsets are less likely to occur.
[0188]
Further, when this toner is used in a fixing device having a fixing nip portion, the time required for toner particles to pass through the fixing nip portion is Δt [second], and the relaxation elastic modulus of the toner at 0.01 second is Assuming that the initial relaxation elastic modulus is G (0.01) and the relaxation elastic modulus of the toner at Δt seconds is G (Δt), the relationship of G (0.01) / G (Δt) ≦ 10 is satisfied. More preferably, the relationship of 1 ≦ G (0.01) / G (Δt) ≦ 8 is satisfied, and more preferably, the relationship of 1 ≦ G (0.01) / G (Δt) ≦ 6 is satisfied. Is more preferred. By satisfying such a relationship, the tearing of the toner due to the decrease in the elastic modulus of the toner particles and the offset are less likely to occur.
On the other hand, when G (0.01) / G (Δt) exceeds 10, toner tearing and offset tend to occur. The relaxation elastic modulus of the toner is determined, for example, by the composition of the constituent materials of the toner (for example, the molecular weight of the resin component, the type of the constituent monomer, the composition of the wax and the external additive, the content of each constituent component, etc.) and the production of the toner. It can be adjusted by the conditions (for example, the raw material temperature in the kneading step, the kneading time, the cooling rate of the kneaded material in the cooling step, the processing temperature in the thermal sphering step, and the like).
[0189]
When a resin containing a block polyester as described above is used as a resin component constituting the toner, crystals usually mainly composed of crystalline blocks of the block polyester exist in the toner.
Such a crystal preferably has an average length (average length in the longitudinal direction) of 10 to 1000 nm, and more preferably 50 to 700 nm. When the length of the crystal is in such a range, the stability of the shape of the toner is particularly excellent, and particularly excellent stability against mechanical stress is exhibited. In particular, the external additive is more reliably held in the vicinity of the surface of the toner particles (it is possible to effectively prevent the external additive from being buried in the base particles). And the like, which is particularly excellent in stability, and hardly causes filming or the like. The size of the crystals can be changed, for example, by controlling the production conditions and the like of the block polyester used as a raw material component, to change the molecular weight and randomness of the block polyester, or to change the mixing ratio between the block polyester and the amorphous polyester. Or by changing the conditions of the above-described kneading step and cooling step.
[0190]
The average length of the crystal can be measured by a transmission electron microscope (TEM), small-angle X-ray scattering measurement, or the like.
Further, the composition of the non-crystalline polyester (such as the constituent monomer) such as the composition of the block polyester contained in the toner (constituent monomer, abundance ratio of the crystalline block, etc.), average weight molecular weight Mw, glass transition point, softening point, melting point , The average weight molecular weight Mw, the glass transition point, the softening point, and the like are preferably the same as those described in the item of the constituent material of the raw material 5, but may be changed during the manufacturing process.
Further, the toner described above is preferably used for a contact-type fixing device as described below.
[0191]
Next, a fixing device and an image forming apparatus will be described.
8 is an overall configuration diagram showing a preferred embodiment of the image forming apparatus, FIG. 9 is a sectional view of a developing device included in the image forming apparatus of FIG. 8, and FIG. 10 is a fixing device used in the image forming apparatus of FIG. FIG. 11 is a perspective view showing a detailed structure of the apparatus, showing a partly broken section, FIG. 11 is a sectional view of a main part of the fixing device of FIG. 10, and FIG. 12 is a perspective view of a peeling member constituting the fixing device of FIG. 13 is a side view showing a mounting state of a peeling member constituting the fixing device of FIG. 10, FIG. 14 is a front view of the fixing device of FIG. 10 as viewed from above, and FIG. FIG. 16 is a schematic diagram for explaining the arrangement angle of the peeling member, FIG. 16 is a diagram schematically illustrating the shape of the fixing roller and the pressure roller, and the shape of the nip portion, and FIG. FIG. 18 is a cross-sectional view taken along an X-ray. Fig, 19 showing the shape schematically shows a cross-sectional view along line Y-Y in FIG. 18 (a), the FIG. 20, a fixing roller, a cross-sectional view for explaining a gap between the peeling member.
[0192]
An image carrier 330 composed of a photosensitive drum is provided in the apparatus main body 320 of the image forming apparatus 310, and is driven to rotate in a direction indicated by an arrow by a driving unit (not shown). Around the image carrier 330, a charging device 340 for uniformly charging the image carrier (photoconductor) 330 along the rotation direction, and forms an electrostatic latent image on the image carrier 330. Device 350, a rotary developing device 360 for developing an electrostatic latent image, and an intermediate transfer device 370 for primarily transferring a single-color toner image formed on the image carrier 330.
[0193]
The rotary developing device 360 has a yellow developing device 360Y, a magenta developing device 360M, a cyan developing device 360C, and a black developing device 360K mounted on a support frame 3600, and the support frame 3600 is rotationally driven by a drive motor (not shown). It has a configuration. The plurality of developing devices 360Y, 360C, 360M, and 360K are selectively rotated so that the developing roller 3604 of one developing device faces the image carrier 330 for each rotation of the image carrier 330. Have been. In each of the developing devices 360Y, 360C, 360M, and 360K, a toner storage unit that stores a toner of each color is formed.
[0194]
The developing devices 360Y, 360C, 360M, and 360K all have the same structure. Therefore, although the structure of the developing device 360Y will be described here, the structures and functions of the developing devices 360C, 360M, and 360K are the same.
[0195]
As shown in FIG. 9, in the developing device 360Y, a supply roller 3603 and a developing roller 3604 are mounted on a housing 3601 that accommodates the toner T therein, and when the developing device 360Y is positioned at the above-described developing position. A developing roller 3604 functioning as a “toner carrier” is positioned in contact with an image carrier (photoconductor) 330 or at a predetermined gap, and these rollers 3603 and 3604 are provided on the main body side. It is configured to engage with a rotating drive unit (not shown) and rotate in a predetermined direction. The developing roller 3604 is formed in a cylindrical shape from a metal or alloy such as copper, stainless steel, or aluminum so that a developing bias is applied.
[0196]
In the developing device 360Y, a regulating blade 3605 for regulating the thickness of the toner layer formed on the surface of the developing roller 3604 to a predetermined thickness is arranged. The regulating blade 3605 includes a plate-like member 3605a such as stainless steel or phosphor bronze, and an elastic member 3605b such as a rubber or resin member attached to the tip of the plate-like member 3605a. The rear end of the plate member 3605a is fixed to the housing 3601. The elastic member 3605b attached to the front end of the plate member 3605a is connected to the rear end of the plate member 3605a in the rotation direction D3 of the developing roller 3604. It is arranged so as to be located on the upstream side.
[0197]
The intermediate transfer device 370 is disposed so as to face the image carrier 330 on the back surface of the intermediate transfer belt 410, the intermediate transfer belt 410 driven by both rollers in the direction indicated by the arrow in FIG. A primary transfer roller 420, a transfer belt cleaner 430 that removes residual toner on the intermediate transfer belt 410, and a four-color full-color image formed on the intermediate transfer belt 410 are provided facing the drive roller 390. And a secondary transfer roller 440 for transferring the image onto paper.
[0198]
A paper feed cassette 450 is provided at the bottom of the apparatus main body 320, and a recording medium in the paper feed cassette 450 passes through a pickup roller 460, a recording medium transport path 470, a secondary transfer roller 440, and a fixing device 490, and is supplied to a paper discharge tray. 500. In addition, 530 is a conveyance path for double-sided printing.
[0199]
The operation of the image forming apparatus 310 having the above configuration will be described. When an image forming signal is input from a computer (not shown), the image carrier 330, the developing roller 3604 of the developing device 360, and the intermediate transfer belt 410 are driven to rotate. First, the outer peripheral surface of the image carrier 330 is charged by the charging device 340. The outer peripheral surface of the uniformly charged and uniformly charged image carrier 330 is selectively exposed by an exposure device 350 according to image information of a first color (for example, yellow), and a yellow electrostatic latent image is formed. An image is formed.
[0200]
On the other hand, in the developing device 360Y, the two rollers 3603 and 3604 rotate while being in contact with each other, so that the yellow toner rubs against the surface of the developing roller 3604 and a toner layer having a predetermined thickness is formed on the surface of the developing roller 3604. . Then, the elastic member 3605b of the regulating blade 3605 elastically contacts the surface of the developing roller 3604, and regulates the toner layer on the surface of the developing roller 3604 to a predetermined thickness.
[0201]
At the latent image position formed on the image carrier 330, the developing device 360 </ b> Y for yellow rotates and the developing roller 3604 abuts thereon, so that the toner image of the yellow electrostatic latent image is formed on the image carrier 330. Then, the toner image formed on the image carrier 330 is transferred onto the intermediate transfer belt 410 by the primary transfer roller 420.
At this time, the secondary transfer roller 440 is separated from the intermediate transfer belt 410.
[0202]
The above process is repeated for the second, third, and fourth colors of the image forming signal, and the latent image formation, development, and transfer by one rotation of the image carrier 330 and the intermediate transfer belt 410 are repeated. Are superimposed and transferred on the intermediate transfer belt 410. Then, at the timing when this full-color image reaches the secondary transfer roller 440, the recording medium is supplied from the transport path 470 to the secondary transfer roller 440. At this time, the secondary transfer roller 440 is pressed against the intermediate transfer belt 410 and A secondary transfer voltage is applied, and the full-color toner image on the intermediate transfer belt 410 is transferred onto a recording medium. Then, the toner image transferred onto the recording medium is heated and pressed by a fixing device 490 and fixed. The toner remaining on the intermediate transfer belt 410 is removed by the transfer belt cleaner 430.
[0203]
In the case of double-sided printing, the recording medium that has exited the fixing device 490 is switched back so that the rear end thereof is at the front end, is supplied to the secondary transfer roller 440 via the double-sided printing conveyance path 530, and is supplied to the intermediate transfer roller 440. The full-color toner image on the transfer belt 410 is transferred onto a recording medium, and is again heated and pressed by the fixing device 490 to be fixed.
8, a fixing device 490 includes a fixing roller 510 having a heat source and a pressing roller 520 pressed against the fixing roller 510. A line connecting the fixing roller 510 and the axis of the pressing roller 520 has an angle θ from a horizontal line. It is arranged to have. Note that 0 ° ≦ θ ≦ 30 °.
[0204]
Next, the fixing device 490 will be described in detail.
10 and 14, a fixing roller 510 is rotatably mounted in a housing 540, and a driving gear 580 is connected to one end of the fixing roller 510. A pressure roller 520 is rotatably mounted facing the fixing roller 510. The length of the pressure roller 520 in the axial direction is shorter than that of the fixing roller 510, and a bearing 550 is provided in the empty space. Both ends of the pressure roller 520 are supported by the bearings 550. A pressure lever 560 is rotatably provided on the bearing 550, and a pressure spring 570 is disposed between one end of the pressure lever 560 and the housing 540, whereby the pressure roller 520 and the fixing roller 510 are pressed. It is configured to be.
[0205]
11, a fixing roller 510 includes a metal cylinder 510b having a heat source 510a such as a halogen lamp therein, an elastic layer 510c made of silicon rubber or the like provided on the outer periphery of the cylinder 510b, and a surface of the elastic layer 510c. It is composed of a surface layer (not shown) made of fluoro rubber and fluoro resin (for example, pertetrafluoroethylene (PTFE)), and a rotating shaft 510d fixed to the cylindrical body 510b.
[0206]
The pressure roller 520 has a metal cylindrical body 520b, a rotating shaft 520d fixed to the cylindrical body 520b, a bearing 550 for supporting the rotating shaft 520d, and a fixing roller 510, like the fixing roller 510, on the outer periphery of the cylindrical body 520b. The elastic layer 520c includes a provided elastic layer 520c and a surface layer (not shown) made of fluoro rubber or fluoro resin coated on the surface of the elastic layer 520c. The thickness of the elastic layer 510c of the fixing roller 510 is extremely smaller than the thickness of the elastic layer 520c of the pressing roller 520, whereby the fixing nip 640 is formed such that the pressing roller 520 side is concavely concave.
[0207]
As shown in FIGS. 10 and 11, support shafts 590 and 600 are provided on both side surfaces of the housing 540, and the peeling member 610 and the pressure roller 520 on the fixing roller 510 side are respectively provided on the support shafts 590 and 600. The side peeling member 620 is rotatably mounted. As a result, the peeling members 610 and 620 are disposed downstream of the fixing nip portion 640 in the recording medium conveyance direction in the axial direction of the fixing roller 510 and the pressure roller 520.
[0208]
As shown in FIGS. 12 and 13, the peeling member 610 on the side of the fixing roller 510 has a resin sheet or a metal sheet as a base material, and has a fluorine-based resin layer formed on the surface of the base material. The peeling member 310 includes a plate-like peeling portion (base material) 610a, a bent portion 610b bent in an L-shape behind the peeling portion 610a toward the fixing roller 610, and a lower portion at both ends of the peeling portion 610a. The support piece 610c is bent in the direction, a fitting hole 610d formed in the support piece 610c, and a guide part 610e extending forward on both sides of the peeling part 610a.
[0209]
The peeling section 610a is disposed so as to be inclined toward the exit (nip exit 641) of the fixing nip section 640, and the tip of the peeling section 610a is in non-contact with and close to the fixing roller 510. The support shaft 590 described with reference to FIG. 11 is fitted into the fitting hole 610d of the support piece 610c. The guide portion 610e is urged against the housing 540 by a spring 630, so that the leading end of the guide portion 610e is in contact with the fixing roller 510. As a result, the gap between the leading end of the peeling portion 610a and the surface of the fixing roller 510 is formed. The gap is kept constant at all times.
[0210]
The peeling member 620 on the pressure roller 520 side has the same shape as the peeling member on the fixing roller 510 side. However, as shown in FIGS. 10 and 11, the leading end of the peeling section 620a is larger than the leading end of the peeling section 610a. It is arranged on the downstream side in the medium transport direction. Further, the tip of the guide portion 620e is in contact with the peripheral surface of the bearing 550 of the pressure roller 520 at point P, whereby the gap between the tip of the peeling portion 620a and the surface of the pressure roller 520 is always constant. Is to be.
[0211]
In the present embodiment, as shown in FIGS. 10 and 11, the peeling members 610 and 620 are disposed in the axial direction of the fixing roller 510 and the pressure roller 520 on the downstream side of the nip 640 in the recording medium transport direction. The distal end of the peeling member 610 on the side of the fixing roller 510 is disposed so as to be inclined toward the exit of the nip 640, and is in non-contact with and close to the fixing roller 510. The leading end of the peeling member 320 on the pressure roller 520 side is disposed downstream of the leading end of the peeling member 610 on the fixing roller 510 side in the recording medium transport direction.
[0212]
As shown in FIG. 13, the guide portion 610 e of the peeling member 610 on the fixing roller 510 side is urged to the housing 540 by a spring 333, whereby the tip of the guide portion 610 e is in contact with the fixing roller 510. As a result, positioning is performed such that the gap between the tip of the peeling section 610a and the surface of the fixing roller 510 is always constant.
[0213]
The peeling member 620 on the pressure roller 520 side has the same shape as the peeling member on the fixing roller 510 side, and as shown in FIGS. 10 and 11, the leading end of the peeling section 620a is larger than the leading end of the peeling section 610a. The guide 620e is disposed on the downstream side in the transport direction, and the tip of the guide 620e is in contact with the surface of the bearing 550 of the pressure roller 520 at a point P, whereby the tip of the peeling portion 620a and the surface of the pressure roller 520 are connected. Positioning is performed so that the gap between them is always constant. For this purpose, as shown in FIG. 14, the axial length of the pressure roller 520 is shorter than that of the fixing roller 510, and bearings 550 are provided in the empty space. Supported.
[0214]
In the case of double-sided printing, the recording medium printed on one side is peeled off by the peeling member 610 on the fixing roller 510 side, and then switched back so that the rear end of the recording medium becomes the front end, and passed through the conveyance path 530 for double-sided printing. The full color toner image on the intermediate transfer belt 410 is supplied to the secondary transfer roller 440 and is transferred onto a recording medium, and is again heated and pressed by the fixing roller 510 to be fixed. The resulting recording medium is peeled off by the peeling member 620 on the pressure roller 520 side.
[0215]
As described above, the fixing device includes the peeling member disposed in the axial direction of the fixing roller and the pressure roller and on the downstream side of the fixing nip in the recording medium conveyance direction in the vicinity of the fixing roller and the pressure roller. Since the positioning of the peeling member on the fixing roller side is performed on the surface of the fixing roller, and the positioning of the peeling member on the pressing roller side is performed on the bearing surface of the pressing roller, the recording medium is separated from the fixing roller and the pressing roller. Performance can be improved.
[0216]
In this embodiment, as shown in FIG. 15, the fixing roller 510 and the pressure roller 520 are arranged in a substantially horizontal state, and the recording medium 800 is discharged upward from the fixing nip 640. However, it is preferable that the arrangement angle θA of the peeling member 610 with respect to the tangent S of the nip exit 641 of the fixing nip portion 640 is set in the range of −5 to 25 °. By setting the arrangement angle θA of the peeling member 610 with respect to the tangent S of the nip exit 641 of the fixing nip portion 640 to a value in such a range, streaks are less likely to occur in the image, and the peelability is improved. . The arrangement angle θA is “+” on the fixing roller 510 side and “−” on the pressure roller side.
[0219]
Further, the fixing roller 510 and the pressure roller 520 have, for example, substantially constant outer diameters in their respective axial directions (although they may have a substantially cylindrical shape, the outer diameters are small near both ends). It may have a so-called crown shape that is large near the center, or a so-called inverted crown shape in which the outer diameter dimension is large near both ends and small near the center.
[0218]
For example, when the fixing roller 510 and the pressure roller 520 have an inverted crown shape as shown in FIG. 16, the cross-sectional shape of the peeling member 610 is preferably as shown in FIG. When the fixing roller 510 and the pressure roller 520 have a crown shape as shown in FIG. 18, the cross-sectional shape of the peeling member 610 is preferably as shown in FIG.
[0219]
As described above, when the peeling member 610 disposed along the fixing roller 510 has a shape that follows the shape of the nip exit 641 of the nip portion 640, the peeling member 610 on the side of the fixing roller 510 at the time of peeling. The number of contact points between the side edge of the recording medium and the recording medium increases, and the adverse effects caused by concentration of the contact pressure between them, such as winding of the recording medium, disturbance in a formed image, and generation of streaks can be effectively reduced. Can be prevented and suppressed.
[0220]
As shown in FIG. 20, in the fixing device 490, the gap G2 [μm] between the fixing roller 510 and the peeling member 610 near the axial end of the fixing roller 510 is set at the center of the fixing roller 510 in the axial direction. Preferably, the gap G1 [μm] between the fixing roller 510 and the peeling member 610 near the portion is larger than the gap G1 [μm].
By satisfying such a relationship, the following effects can be obtained.
[0221]
That is, since the gap between the peeling member 610 and the fixing roller 510 is small in the vicinity of the central portion in the length direction, the gap management can be simplified without greatly impairing the peelability, and the manufacturing of the fixing device 490 is also possible. It will be easier. Further, even when foreign matter intrusion or paper jam occurs, the peeling member 610 and the fixing roller 510 are hardly damaged by these, and the durability and reliability of the peeling member 610 and the fixing roller are improved. The durability and reliability of the apparatus 490 and the image forming apparatus 310 are also improved. The relationship between G1 and G2 as described above can be determined by, for example, forming the peeling member 610 into an arc shape, forming the distal end portion 610f of the peeling member 610 into an arc shape, or forming the fixing roller 510 into a crown shape. Can be satisfied.
[0222]
In the fixing device as described above, the length of the fixing nip 640 is such that the time required for the toner particles to pass through the fixing nip 640 is 0.02 to 0.2 seconds. Is preferably, and more preferably 0.03 to 0.1 seconds. When the time required for the toner particles to pass through the fixing nip portion 640 falls within such a range, the temperature of the toner is raised to the melting temperature, and the toner is not excessively melted. Secured.
[0223]
The fixing device 490 is suitable for high-speed printing (high-speed fixing, high-speed image formation). Specifically, the fixing device 490 has a feeding speed (feeding speed) of the recording medium 800 of 0.05 to 1.0 m / sec. Preferably, it is 0.2 to 0.5 m / sec. As described above, even when the toner is fixed on the recording medium 800 at a relatively high speed, it is possible to prevent the occurrence of streaks and disturbances in the image, and to prevent peeling failure such as winding of the recording medium 800. It is unlikely to occur.
[0224]
Further, the temperature of the fixing nip portion 640 during operation is preferably from 100 to 220 ° C., and more preferably from 120 to 200 ° C. When the temperature of the fixing nip 640 is in such a range, it is possible to sufficiently prevent a decrease in the fixing strength of the toner due to a temperature drop (temperature drop) when the paper passes.
Further, the fixing set temperature (set temperature of the surface of the fixing roller 510) during the operation is preferably 110 to 220 ° C., and more preferably 130 to 200 ° C. When the set temperature of the fixing roller 510 is in such a range, it is possible to achieve both the fixing strength of the toner and the shortening of the warm-up time (warm-up time).
[0225]
As described above, the fixing device 490 described above is suitable for high-speed printing (high-speed fixing, high-speed image formation). However, in such a fixing device, the toner is in a high temperature state even when the recording medium on which the toner is fixed comes into contact with the peeling member. Therefore, when the conventional toner is used, the toner comes into contact with the peeling member. In this case, the fixed image may be disturbed or streaked. Further, if the fixed toner is brought into contact with the release member in a molten state (low viscosity state), it may be difficult to reliably release the recording medium.
[0226]
On the other hand, the above-described fixing device 490 can suitably apply the toner of the present invention. That is, the toner of the present invention has a small amount of free external additives and is in a state where the external additives are securely attached to the vicinity of the surface of the toner base particles. Further, the toner of the present invention is in a state where the external additive sufficiently covers the toner base particles. Therefore, the toner is reliably fixed to the recording medium when passing through the fixing nip portion 640, and even when the fixed image of the toner comes into contact with the peeling member, the toner particles (toner base particles) are removed from the peeling member. Can be suitably prevented from adhering. As a result, the formed image is unlikely to cause disturbance or streaks.
[0227]
Such an effect is particularly prominent when the toner of the present embodiment is used. That is, since the toner of the present embodiment contains the amorphous polyester having a relatively low softening point, the toner is reliably fixed to the recording medium when passing through the fixing nip portion 640, and the crystalline block Since it contains a block polyester having the following formula, crystals having a high hardness and an appropriate size are likely to precipitate inside the block polyester. The presence of such crystals makes it possible to prevent the melt viscosity of the toner from being lower than a predetermined value even at a relatively high temperature such as at the time of fixing. There will be hard sites. As a result, even when the fixed image of the toner comes into contact with the peeling member, the formed image is less likely to be disturbed or streaked. In addition, in the recording medium to which the toner of the present embodiment is fixed, peeling failure is particularly unlikely to occur, and the peeling member surely peels off the fixing roller.
[0228]
As described above, the mixing device, the toner manufacturing method, and the toner according to the present invention have been described based on the preferred embodiments, but the present invention is not limited thereto.
For example, the mixing device of the present invention is not limited to the configuration described above. That is, in the present invention, the mixing device may be any device having a charging unit for charging at least a part of the inner wall surface of the stirring and mixing chamber, and may be of the air seal type described in the above-described embodiment. It is not limited to a mixing device or the like.
Further, the toner of the present invention is not limited to the toner manufactured by the method described above. For example, in the above-described embodiment, the thermal sphering process is performed after the pulverizing process. However, such a thermal sphering process may be omitted.
[0229]
In the above-described embodiment, the toner is obtained by mixing the toner-producing powder subjected to the thermal sphering treatment with an external additive.However, for example, the toner of the present invention is obtained by a pulverizing process. It may be obtained by subjecting the obtained powder for toner production to an external addition treatment and then to a thermal sphering treatment. That is, the external addition process may be performed as a pre-process such as a thermal sphering process. By performing such an external addition treatment as a pretreatment, the fluidity and dispersibility of the toner particles are improved, and the fusion of the toner particles due to heat can be more effectively prevented or suppressed. In such a case, an external addition process may be further performed after the thermal sphering process. When the external addition process is performed twice or more as described above, at least one of the external addition processes is preferably performed using the mixing apparatus of the present invention (particularly, the mixing apparatus described above). It is more preferable to perform the external addition process using the mixing apparatus of the present invention as described above (particularly, the above-described mixing apparatus).
[0230]
Further, in the above-described embodiment, a configuration using a pulverization method is described as a method for producing the toner production powder, but the toner production powder may be obtained by a spray drying method, a polymerization method, or the like. .
In the above-described embodiment, rutile-anatase-type titanium oxide is described as being added as an external additive.However, for example, by using rutile-anatase-type titanium oxide as one component of a raw material to be supplied to the kneading step, , May be included inside the toner.
[0231]
In the above-described embodiment, ΔT obtained by measuring the endothermic peak of the melting point by differential scanning calorimetry (DSC) has been described as an index indicating the crystallinity, but the index indicating the crystallinity is not limited to this. For example, as an index indicating the crystallinity, a crystallinity measured by a density method, an X-ray method, an infrared method, a nuclear magnetic resonance absorption method, or the like may be used.
[0232]
In the above-described embodiment, the configuration in which the thermal sphering process is performed under dry conditions is described. However, the thermal sphering process may be performed under wet conditions, such as in a solution.
Further, in the above-described embodiment, a configuration in which a continuous twin-screw extruder is used as the kneader has been described, but the kneader used for kneading the raw materials is not limited to this. For kneading the raw materials, for example, various kneaders such as a kneader or a batch type triaxial roll, a continuous biaxial roll, a wheel mixer, a blade type mixer, or the like can be used.
[0233]
In the illustrated configuration, the kneader having a configuration having two screws has been described, but the number of screws may be one, or three or more.
Further, in the above-described embodiment, a configuration using a belt-type cooling device has been described. However, for example, a roll-type (cooling roll-type) cooling device may be used. The cooling of the kneaded material extruded from the extrusion port of the kneader is not limited to the above-described one using the cooler, but may be, for example, air cooling or the like.
[0234]
Further, in the above-described embodiment, a configuration in which a flow path is formed inside the apparatus main body and a charged substance is caused to flow through the flow path to charge the inner wall surface of the stirring and mixing chamber as the mixing apparatus has been described. The invention is not limited to this. For example, the inner wall surface may be charged by applying a current to the inner wall surface of the stirring and mixing chamber.
Further, in the above-described embodiment, the configuration using the compressed air as the gas (gas flow) supplied into the stirring and mixing chamber together with the liquid lubricant has been described, but a gas other than air (for example, helium, neon, argon) , An inert gas such as nitrogen, etc.).
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing a configuration of a first embodiment of a mixing device of the present invention.
FIG. 2 is a longitudinal sectional view schematically showing an enlarged circle A of the mixing apparatus shown in FIG.
FIG. 3 is a perspective view schematically showing a driving unit to which the mixing device shown in FIG. 1 is mounted.
FIG. 4 is a longitudinal sectional view schematically showing a configuration of a mixing apparatus according to a second embodiment of the present invention.
FIG. 5 is a longitudinal sectional view schematically showing an example of a configuration of a kneader and a cooler used in a method for producing a toner.
FIG. 6 is a model diagram of a differential scanning calorimetric analysis curve near the melting point of the block polyester obtained when differential scanning calorimetry is performed on the block polyester.
FIG. 7 is a flowchart for softening point analysis.
FIG. 8 is an overall configuration diagram illustrating a preferred embodiment of an image forming apparatus.
9 is a sectional view of a developing device included in the image forming apparatus of FIG.
FIG. 10 is a perspective view showing a detailed structure of a fixing device used in the image forming apparatus of FIG.
11 is a sectional view of a main part of the fixing device of FIG. 10;
FIG. 12 is a perspective view of a peeling member included in the fixing device of FIG.
FIG. 13 is a side view showing an attached state of a peeling member constituting the fixing device of FIG. 10;
14 is a front view of the fixing device of FIG. 10 as viewed from above.
FIG. 15 is a schematic diagram for explaining an arrangement angle of a peeling member with respect to a tangent line at an outlet of a nip portion.
FIG. 16 is a diagram schematically illustrating shapes of a fixing roller and a pressure roller and a shape of a nip portion.
FIG. 17 is a sectional view taken along line XX of FIG. 16 (a).
FIG. 18 is a diagram schematically illustrating shapes of a fixing roller and a pressure roller and a shape of a nip portion.
FIG. 19 is a sectional view taken along line YY in FIG.
FIG. 20 is a cross-sectional view illustrating a gap between a fixing roller and a peeling member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Kneader 2 ... Process part 21 ... Barrel 22, 23 ... Screw 24 ... Fixing member 25 ... 1st area 26 ... 2nd area 27 ... 3rd area 28, 29 ... Temperature transition area 3 Head part 31 Internal space 32 Extrusion port 33 Cross-sectional area gradually decreasing part 4 Feeder 5 Raw material 6 Cooler 61, 62, 63, 64 Roll 611 621, 631, 641 ... Rotating shaft 65, 66 ... Belt 67 ... Discharge part 7 ... Kneaded material 71 ... External additive 100, 100 '... Mixing device 110 ... Device body 111 ... First Partition plate 112 Second partition plate 113 Screw 114 Bracket 115 Compressed air inlet 116 Air inlet 117 Lubricant inlet 118 Lubricant inlet 119 recess 120 …… Agitated mixing chamber 121 Upper lid 122 Trap 123 Filter 124 Inner wall 125 Outer wall 126 Flow path 127 Charged substance 128 Induction path 129 Cylindrical member 1291 First conductive layer 1292 ...... Insulating layer 1293 Second conductive layer 1201 Inner wall surface 130 Water cooling chamber 131 Cooling water inlet 132 Cooling water outlet 140 Bearing unit 150 Rotating shaft 151 Bolt 152 engaging part 158 gap part 160 first seal member 161 second seal member 170 stirring blade 180 bearing 190 mounting chamber 200 driving device 210 driving Shaft 211... Engaging part 220... Flange 221... Lock claw 230... Timer 240. H 310 image forming apparatus 320 apparatus main body 330 image carrier 340 charging apparatus 350 exposure apparatus 360 rotary developing apparatus 3600 support frame 3601 housing 3603 supply roller 3604 ... developing roller 3605 ... regulating blade 3605a ... plate member 3605b ... elastic member 360Y ... yellow developing device 360M ... magenta developing device 360C ... cyan developing device 360K ... black developing device 370 ... Intermediate transfer device 390 Drive roller 400 Follower roller 410 Intermediate transfer belt 420 Primary transfer roller 430 Transfer belt cleaner 440 Secondary transfer roller 450 Paper feed cassette 460 Pickup roller 470 …… Recording medium conveyance path 490 …… Attaching device 500 ··· Paper ejection tray 510 ··············································································································· ... Cylinder 520c ... Elastic layer 520d ... Rotating shaft 530 ... Convey path for double-sided printing 540 ... Housing 550 ... Bearing 560 ... Pressurizing lever 570 ... Pressurizing spring 580 ... Drive gear 590 ... Support Axis 600 Support shaft 610 Peeling member 610a Peeling part 610b Bend 610c Support piece 610d Fitting hole 610e Guide part 610f Tip part 620 Peeling member 620a ... Peeling section 620 e Guide section 630 Spring 640 Fixing nip section 641 Nip exit 800 Recording medium T Toner S… tangent G1… gap G2… gap

Claims (14)

A stirring and mixing chamber into which the toner production powder and the external additive are charged,
A rotation shaft that is rotated by the rotation driving means,
A stirring blade fixed to the rotating shaft, and disposed in the stirring and mixing chamber,
A mixing apparatus for stirring and mixing the toner production powder and the external additive, and externally adding the external additive to the toner production powder,
A mixing device comprising a charging unit for charging an inner wall surface of the stirring and mixing chamber to the same polarity as the external additive. A channel is provided inside the wall surface of the stirring and mixing chamber, and the inner wall surface of the stirring and mixing chamber is charged by moving charged powder charged to the same polarity as the external additive by frictional charging in the channel. The mixing device according to claim 1. The mixing device according to claim 2, wherein the average particle size of the charged powder is 0.05 to 0.3 mm. The mixing device according to claim 2, wherein the flow speed of the charged powder is 10 to 1000 g / sec. The mixing device according to any one of claims 2 to 4, wherein air is previously contained in the charged powder. The mixing device according to claim 2, wherein a spiral guide path is formed in the flow path. The mixing device according to any one of claims 1 to 6, wherein a voltage is applied to charge the inner wall surface of the stirring and mixing chamber to the same polarity as the external additive. The mixing device according to claim 7, wherein the absolute value of the voltage is 1 to 10 kV. A tube arranged so as to surround at least a part of the stirring and mixing chamber, and having an insulating layer made of an insulating material interposed between two conductive layers made of a conductive material. Having a shaped member,
The mixing device according to claim 7, wherein the voltage is applied such that a layer provided on an outer peripheral surface side of the member among the conductive layers functions as an electrode plate. A method for producing a toner, comprising a step of stirring and mixing a toner production powder and an external additive using the mixing apparatus according to any one of claims 1 to 9. A toner produced by using the mixing device according to claim 1. A toner manufactured by the manufacturing method according to claim 10. 13. The toner according to claim 11, wherein the content of the external additive is 0.5 to 5 wt%. The toner according to any one of claims 11 to 13, wherein a ratio of the external additive that is free from the toner base particles is 3 wt% or less.

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