JP2009288394A - Image forming method, fixing method and magnetic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method excellent in on-demand quality and low temperature fixability, preventing contamination of a fixing roller or winding of a sheet on a roller even in long-term use. <P>SOLUTION: The image forming method includes a fixing step of forming a nip between a pressurizing member and a rotatable image heating member and fixing an image by heating and pressurizing. The image heating member has an elastic layer inside and a heat accumulating layer outside having a heat capacity of 100 to 600 J/m<SP>2</SP>K. The image heating member contains a heat conductive filler having thermal conductivity of not less than 5.0 W/mK. The filler is an Al and/or Zn compound. The toner is a magnetic toner containing a binder resin, a magnetic material, at least one kind of release agent compatible with the binder resin, and at least one kind of release agent incompatible with the binder resin. When the softening temperature Tn [°C] and the flow start temperature Tr [°C] of the magnetic toner are measured by a flow tester, the respective plunger positions Pn [mm] and Pr [mm] of the flow tester satisfy 1.1≤Pn/Pr≤1.5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming method, a fixing method, and a magnetic toner used for electrophotography, electrostatic recording, magnetic recording, and the like.

  Conventionally, in an image forming apparatus, a contact heating type apparatus has been widely used as an apparatus for heating and fixing an unfixed toner image formed and supported on a recording material as a permanently fixed image. In this contact heating type fixing device, a rotating member (hereinafter referred to as a fixing roller) whose surface temperature in contact with a recording material is heated to a predetermined fixing temperature is brought into contact with the recording material at a nip portion to perform recording. The unfixed toner image on the material is heat-fixed as a permanently fixed image.

  As one of the heating methods for the fixing roller, there is a conventional internal heating method. In this method, heating means (heating source: heater or the like) is disposed inside the fixing roller, and the fixing roller is heated from the inside to heat the surface of the fixing roller to a predetermined fixing temperature. However, the internal heating method is inferior in on-demand because it is necessary to heat the entire roller.

  Various studies have been made in order to cope with the on-demand property, and the film heat fixing method is a useful fixing method. This is a system in which the heater directly heats through the film, so that the heat of the heater can be efficiently applied to the recording material. However, the film heat fixing may cause a problem that the film is torn during long-term use.

  As a new fixing method to eliminate such concerns, an external heating method (surface heating method) has been studied.

  In the external heating system, the surface of the fixing roller can be rapidly heated because the fixing roller is heated from the outside by a low heat capacity heating means such as a small diameter heating roller incorporating a ceramic heater or a halogen heater. is there. Therefore, the warm-up time compared to the internal heating system and the time from when a print signal is received until the recording material on which the unfixed toner image is formed is heated and fixed (hereinafter referred to as the first printout time). Can be shortened. Along with these, on-demand is also improved, which is preferable.

  As a technique related to such an external heating method, for example, there is a technique in which the inside of the fixing roller is thermally insulated and the outermost layer is made to have high thermal conductivity by containing a heat conductive filler (see Patent Documents 1 and 2). However, this technology shortens the warm-up time and increases the on-demand characteristics, improving the low-temperature fixability, but leaves room for improvement with respect to the wrapping of the recording material around the fixing roller and the fixing roller. .

  Many studies have been made on toners for improving low-temperature fixability. For example, a toner having a small particle diameter containing crystalline polyester has been reported, and a toner that has excellent fixability and can form an image with high resolution has been proposed (see Patent Document 3).

  Further, a toner capable of achieving both offset resistance and low-temperature fixability by adjusting the outflow start temperature and the outflow end temperature by a constant load extrusion type capillary rheometer (flow tester) has been proposed (Patent Literature). 4).

  Furthermore, a toner has been proposed that can achieve low-temperature fixability by defining the melting point of each toner containing crystalline polyester and two types of waxes (see Patent Document 5).

  However, even with such a toner, it is difficult to overcome all the problems of low-temperature fixability, wrapping, and fixing roller contamination in the above on-demand image forming method, and there is still room for improvement. was there.

JP 2004-317788 A JP 2007-121441 A JP-A-4-184358 JP 2002-215756 A JP 2005-234046 A

  An object of the present invention is to provide an image forming method, a fixing method, and a magnetic toner which are excellent in on-demand property and low-temperature fixing property and do not cause fouling or winding of a fixing roller even in long-term use.

The image forming method, the fixing method, and the magnetic toner of the present invention are characterized by the following configurations.
(1) A charging step of charging the electrostatic latent image carrier with charging means, an exposure step of exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and the electrostatic latent image with toner A development process for developing and forming a toner image, a transfer process for transferring the toner image to a recording material with or without an intermediate transfer member, and a recording material carrying the toner image can be rotated with a pressure member. In an image forming method including a fixing step of fixing by heating and pressing by passing a nip formed by an image heating member,
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The toner applied to the image heating apparatus includes at least one binder resin, a magnetic material, and one or more release agents compatible with the binder resin, and one kind of release agent incompatible with the binder resin. The magnetic toner is contained as described above. When the softening temperature of the magnetic toner is Tn [° C.] and the outflow start temperature is Tr [° C.], the respective plunger positions are Pn [mm] and Pr [mm]. ], An image forming method characterized by satisfying 1.1 ≦ Pn / Pr ≦ 1.5.
(2) The image forming method according to (1), wherein Rz of the image heating member is 2.0 μm or more and 20.0 μm or less.
(3) The image forming method according to (1) or (2), wherein the heat conductive filler is contained in an amount of 7 parts by mass to 60 parts by mass with respect to 100 parts by mass of the rubber forming the heat storage layer.
(4) The image forming method according to any one of (1) to (3), wherein the heat storage layer has a thickness of 50.0 μm to 500.0 μm.
(5) The image forming method according to any one of (1) to (4), wherein the elastic layer has a thermal conductivity of 0.15 W / mK or less.
(6) The image forming method according to any one of (1) to (5), wherein the image heating member includes means for heating from the outside.
(7) The magnetic toner contains 0.2 to 1.0 part by mass of a crosslinking agent with respect to 100 parts by mass of the binder resin. The image forming method described.
(8) The image forming method according to any one of (1) to (7), wherein an average circularity of the magnetic toner is 0.960 or more.
(9) When one melting point of the release agent compatible with the binder resin is Tm1 [° C.] and one melting point of the release agent incompatible with the binder resin is Tm2 [° C.] The image forming method according to any one of (1) to (8), wherein Tm1 is 50 ° C. or higher and Tm1 ≦ Tm2 + 10 is satisfied.
(10) With respect to 100 parts by weight of the binder resin, 2 parts by weight or more and 30 parts by weight or less of a release agent compatible with the binder resin, and 2 parts of a release agent incompatible with the binder resin. The image forming method according to any one of (1) to (9), wherein the image forming method contains not less than 30 parts and not more than 30 parts by mass.
(11) The image forming method according to any one of (1) to (10), wherein the incompatible release agent is a crystalline polyester.
(12) The image forming method according to (11), wherein the crystalline polyester is a polycondensate of a linear dicarboxylic acid and a linear aliphatic dialcohol.
(13) The image forming method according to (11) or (12), wherein the crystalline polyester has an acid value of 5 [mg KOH / g] or less.
(14) The image forming method according to any one of (11) to (13), wherein the crystalline polyester has a number average molecular weight of 2,000 to 7,000.
(15) In a fixing method in which a toner image formed on a recording material is heated and pressurized and fixed by passing through a nip formed by a pressure member and a rotatable image heating member.
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The toner is a magnetic toner containing at least one binder resin, a magnetic material, and one or more release agents compatible with the binder resin, and at least one release agent incompatible with the binder resin. When the softening temperature of the magnetic toner measured by the flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the plunger positions are Pn [mm] and Pr [mm], respectively. ≦ Pn / Pr ≦ 1.5 satisfying the fixing method.
(16) A charging step of charging the electrostatic latent image carrier with charging means, an exposure step of exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and the electrostatic latent image with toner A development process for developing and forming a toner image, a transfer process for transferring the toner image to a recording material with or without an intermediate transfer member, and a recording material carrying the toner image can be rotated with a pressure member. In a magnetic toner used in an image forming method having a fixing step of fixing by heating and pressing by passing a nip formed by an image heating member,
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The magnetic toner is a magnetic toner containing at least one binder resin, a magnetic material, and at least one release agent compatible with the binder resin, and at least one release agent incompatible with the binder resin. When the softening temperature of the magnetic toner measured by the flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the respective plunger positions are Pn [mm] and Pr [mm]. 1. Magnetic toner satisfying 1 ≦ Pn / Pr ≦ 1.5.

  According to the present invention, it is possible to provide an image forming method, a fixing method, and a magnetic toner that are excellent in low-temperature fixability, fixing roller contamination, and wrapping resistance.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to an image forming method, a fixing method, and a magnetic toner, and a charging step for uniformly charging an image carrier, a latent image forming step for forming a latent image by exposing the charged image carrier, With respect to the developing process for developing the electrostatic latent image to form a toner image and the transfer process for transferring the developed image onto a recording material, a conventionally known electrophotographic process can be applied and is not particularly limited.

The present inventors include a charging step of charging the electrostatic latent image carrier with charging means, an exposure step of exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and the electrostatic latent image. A developing process for forming a toner image by developing the toner image, a transfer process for transferring the toner image to a recording material with or without an intermediate transfer member, and a recording material carrying the toner image as a pressure member. In an image forming method including a fixing step of fixing by heating and pressing by passing through a nip formed by a rotatable image heating member,
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The magnetic toner applied to the image heating apparatus includes at least one binder resin, a magnetic material, and one or more release agents compatible with the binder resin, and one release agent incompatible with the binder resin. A magnetic toner containing at least seeds, and when the softening temperature of the magnetic toner measured by a flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the respective plunger positions are Pn [mm] and Pr [ mm], satisfying 1.1 ≦ Pn / Pr ≦ 1.5 satisfies the requirement of high temperature fixability without causing wrapping or fusing roller contamination even in an on-demand image forming method. Was obtained, and the present invention was achieved.

Image heating apparatus of the present invention, an image heating member has a low thermal conductive elastic layer inside, the outside heat storage capacity per unit surface area of the image heating member is less 100 J / m ² K or more 600 J / m ² K An image heating apparatus having a layer.

Considering the thermal efficiency at the time of fixing, it is important to transmit the fixing heat to the recording material without loss of heat, but the heat stored in the heat storage layer may be lost through the metal core. However, according to the study by the present inventors, it has been found that such a heat loss can be greatly reduced by disposing a low thermal conductive elastic layer below the heat storage layer. Further, if the heat storage layer has a high heat capacity, a sufficient amount of heat can be imparted to the recording material during fixing, so that fixing at a lower temperature is possible. However, excessive heat leads to energy loss. While suppressing Ross such heat, in order to impart sufficient heat to the recording material, it was important to control the heat capacity of the heat storage layer below 100 J / m ² K or more 600J / m ² K.

When the heat capacity of the heat storage layer is less than 100 J / m ² K, the heat dissipation amount increases and the recording material is easily deprived of heat. For this reason, the heat energy for heating the image heating member increases, so that the low-temperature fixability is impaired when compared at the same fixing temperature. On the other hand, if the heat capacity of the heat storage layer exceeds 600 J / m ² K, the temperature rise rate of the image heating member is lowered, and the warm-up time is extended.

  Furthermore, it has been found that the low-temperature fixability can be further improved by controlling the state in the vicinity of the surface of the image heating member as the inventors have studied.

  That is, it is important to provide a gradient in the dispersibility of the filler in the heat storage layer so that a large amount of filler exists in the vicinity of the surface of the image heating member.

  Specifically, the ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is the total element amount detected by EPMA. It is 5.0 mass% or more and 45.0 mass% or less with respect to. More preferably, they are 10.0 mass% or more and 40.0 mass% or less.

  By containing aluminum and zinc, the filler can easily obtain high thermal conductivity and can be easily applied to the image heating member of the present invention. Therefore, in the present invention, aluminum and / or zinc element is used. At this time, EPMA was used as a detection method of the heat conductive filler. EPMA measures an element existing at a depth of several μm from the surface, and the detected aluminum and zinc elements correspond to the amount of thermally conductive filler existing at a depth of several μm from the surface. Thereby, the heat conductive filler amount of the heat storage layer surface vicinity can be measured.

  When the proportion of the aluminum element and / or zinc element present in the vicinity of the surface of the image heating member as measured by EPMA is less than 5.0% by mass, the thermal conductivity in the vicinity of the surface of the image heating member is low. For this reason, in order to maintain the surface of the image heating member at a high temperature, it is necessary to continuously apply a heat quantity higher than that of the heating means, resulting in a large heat loss. Also, with a relatively low heat of fixing, sufficient low-temperature fixability cannot be obtained due to heat loss. On the other hand, when the proportion of the aluminum element and / or zinc element present in the vicinity of the surface of the image heating member as measured by EPMA is more than 45.0% by mass, generally the heat containing aluminum element and / or zinc element is present. Since the conductive filler has a higher affinity with the toner than the rubber forming the fixing roller, the adhesion between the fixing roller and the toner is increased, and a low temperature offset occurs.

  In order to improve the on-demand property, the heat conductive filler in the image heating member configuration of the present invention needs to have a high heat conductivity, specifically 5.0 W / mK or more. If it is less than 5.0 W / mK, the heat loss increases with a decrease in heat transfer efficiency, and the fixing temperature increases.

  When the image heating member of the present invention is configured as described above, the thermal responsiveness is improved and the low-temperature fixability can be improved. However, generally, the heat conductive filler containing an aluminum element and / or a zinc element has higher affinity with the toner than the rubber forming the fixing roller as described above. Therefore, when heat for fixing is applied to the image heating member, the toner on the recording material causes fusion with the image heating device. As a result, the recording material after printing is curled, so-called wrapping occurs, and the image heating device is contaminated with toner, and the fixing roller is soiled particularly during long-term use. It was.

  Therefore, various studies were made on the toner in order to improve the wrapping property and the fusing roller stain and to improve the low temperature fixing property.

  Considering the fixing process, the toner receives heat from the fixing member, and the heat is transferred to the inside of the toner. The contained release agent melts and the toner is plasticized and deformed to obtain a fixed image. As the behavior of the release agent at that time, when the resin melts, the binder resin soaks into the binder resin, and when it exudes to the outside of the toner, the releasing effect is exhibited. At this time, it is known that the volume expansion of the toner occurs due to the melting of the release agent.

  At this time, one or more release agents compatible with the binder resin and one or more release agents incompatible with the binder resin are present in the toner, so that only one type of release agent exists. The inventors have found that large volume expansion changes occur that cannot be achieved. Further, it has been found that a superior release effect prevents winding and fixing roller contamination, and that excellent low-temperature fixability is exhibited. This is considered as the following reason.

  Considering the behavior during fixing, the release agent that is compatible with the binder resin melts and then oozes into the binder resin. On the other hand, a release agent that is incompatible with the binder resin is incompatible with either the release agent or the binder resin that is compatible in the temperature range near the melting point, and exists as a domain in the toner. It is considered that the state is close to the liquid core structure. At this time, both the compatible and incompatible release agents expand in volume, but as described above, the release agents that are incompatible with the binder resin are binder resins and other release agents. Therefore, it is considered that the release agent that stays inside the toner and is compatible with the binder resin is pushed out from the inside of the toner. Due to this extrusion effect, the release agent that is compatible with the binder resin is promoted to exude, and as a result, the release agent that is compatible with the toner surface is transported earlier, and the release effect can be demonstrated quickly. It is done. Thereby, it is considered that the toner on the recording material can exert a releasing effect to prevent wrapping and prevent fixing roller contamination. Further, since the toner has a liquid core structure when receiving heat of fixing, it is considered that excellent low-temperature fixing property can be obtained by quickly deforming by pressure and anchoring to the medium.

  Here, the incompatible release agent refers to a release agent that is incompatible with the binder resin or is extremely incompatible with the binder resin at the melting point of the release agent.

  At this time, it is important to control the volume expansion of the toner so that 1.1 ≦ Pn / Pr ≦ 1.5. When Pn / Pr is smaller than 1.1, that is, it means that the volume expansion is low, and the extrusion of the incompatible release agent is weak, so that the release effect at the time of fixing can be obtained instantaneously. It is difficult to cause fouling of the fixing roller due to heat during fixing. On the other hand, if Pn / Pr is larger than 1.5, the volume expansion becomes very large, but it is necessary to increase the amount of the release agent to cause the volume expansion. Problems arise. From the above results, it is essential to control the volume expansion of the toner so that 1.1 ≦ Pn / Pr ≦ 1.5.

  In order to control the volume expansion of the toner within the above range, it is important to change the degree of dispersion of the release agent in the toner. Specifically, as the component to be included, for example, by adjusting the acid value and hydroxyl value of the release agent, the presence or absence of the compatible or incompatible release agent in the toner is adjusted, and the release agent is released. It is possible to change the degree of swelling of the agent. In addition, by subjecting the magnetic material to hydrophobic treatment, for example, when the toner is produced by suspension polymerization (described later) suitably used in the present invention, the presence state of the magnetic material in the toner can be changed. The state of presence of the release agent can also be changed. In addition, when the toner is manufactured by a so-called pulverization method, the kneading heating temperature, cooling temperature and speed, particle shape, etc. are adjusted. Is possible.

  The toner of the present invention must contain a magnetic material. An incompatible release agent forms a domain in the toner. However, in the suspension polymerization method (described later), which is a preferred method for producing the toner of the present invention, a magnetic material not compatible with the release agent is more Extrusion is performed in the vicinity of the surface layer, and the presence of many magnetic materials in the vicinity of the toner surface layer improves the stress resistance during long-term use. Further, when produced by suspension polymerization, since two types of a release agent that is incompatible with the binder resin and a compatible release agent are present inside the toner in the vicinity, The extrusion effect can be obtained more easily.

  Magnetic materials generally tend to deteriorate fixing properties due to their high specific heat and filler effect. However, incompatible release agents that form domains do not become compatible with binder resins in addition to magnetic materials. As described above, since the liquid core structure is formed at the time of melting, the toner is very easily deformed, and even if the magnetic substance is present in the vicinity of the toner surface layer, it is not affected so much and good low-temperature fixing is achieved. It becomes possible.

  Therefore, the present invention is a toner containing at least one binder resin, a magnetic material, and one or more release agents compatible with the binder resin, and one or more release agents incompatible with the binder resin. Yes, when the softening temperature of the toner measured by the flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the respective flanger positions are Pn [mm] and Pr [mm]. It is important to satisfy ≦ Pn / Pr ≦ 1.5.

At that time, the heat capacity per unit area of the image heating device is not more than 100 J / m ² K or more 600 J / m ² K, and the ratio of aluminum element and / or zinc element present in the surface vicinity of the image heating member, By controlling the amount to 5.0 parts by mass or more and 45.0 parts by mass or less, an appropriate amount of heat without excess or deficiency is given to the toner, and a synergistic effect that easily satisfies 1.1 ≦ Pn / Pr ≦ 1.5 also occurs. As a result, it is possible to prevent wrapping and soiling of the fixing roller during long-term use, and to obtain low-temperature fixability.

  Next, the image heating apparatus of the present invention (hereinafter also referred to as a fixing roller) will be described.

  In the image heating apparatus of the present invention, the heating member that melts and fixes the unfixed toner image on the recording material by heat does not have a heat source inside, and external heat fixing that uses heat accumulation received from the heating means from the surface for toner melting. An apparatus is preferably used. This is because the inside has an elastic layer having a high heat insulating property, so that heat loss is less when heating from the outside.

  As shown in FIG. 1, the image heating member 30 of the present invention has a low thermal conductivity elastic layer (hereinafter referred to as a heat insulating elastic layer or an elastic layer) 32 having a low thermal conductivity and elasticity on the outer periphery of a cored bar 31. In addition, a heat storage layer is formed on the outer side.

  The cored bar 31 of the image heating member of the present invention is formed of, for example, a metal material such as aluminum, iron, or SUM material, or another rigid material such as ceramic. Since the core 31 is insulated from the surface of the fixing roller by the heat insulating elastic layer 32, it may have low thermal conductivity and low heat capacity. The form may be a hollow cylinder.

  The heat insulating elastic layer 32 formed on the outer periphery of the cored bar 31 is a rubber layer having a low thermal conductivity, and the thermal conductivity is adjusted to be smaller than that of the heat storage layer 33. In the present invention, it is preferable that the elastic layer has a thermal conductivity of 0.15 W / mK or less because the heat quantity of the heat storage layer is difficult to escape to the cored bar and there is no loss of heat quantity.

  The thickness of the heat insulating elastic layer 32 is not particularly limited, but is 1.0 mm or more and 5.0 mm or less in order to configure the fixing roller 30 having a small diameter without having an effective heat insulating property and a large heat capacity. Preferably it is 2.0 mm or more and 4.0 mm or less.

  From the viewpoint of durability and heat insulating properties, the heat-insulating elastic layer is fired after forming a compound in which a hollow filler is blended with an organopolysiloxane composition or a compound in which a water-absorbing polymer and water are blended in an organopolysiloxane composition. And what was formed by hardening is preferable.

  A method for forming the heat insulating elastic layer 32 will be exemplified below.

  For example, a silicone rubber composition, which is formed by blending 0.1 to 200.0 parts by mass of a hollow filler having an average particle size of 500 μm or less with 100 parts by mass of a thermosetting organopolysiloxane composition. A balloon rubber layer formed by heat curing the product.

  Here, as the hollow filler, there is a microballoon material or the like that reduces the thermal conductivity like sponge rubber by having a gas portion in the cured product. Such materials may be any of glass balloons, silica balloons, carbon balloons, phenol balloons, acrylonitrile balloons, vinylidene chloride balloons, alumina balloons, zirconia balloons, shirasu balloons and the like.

  The amount of the hollow filler is 0.1 to 200.0 parts by mass, preferably 0.2 to 150.0 parts by mass, with respect to 100 parts by mass of the thermosetting organopolysiloxane composition. Hereinafter, it is more preferably 0.5 parts by mass or more and 100.0 parts by mass or less. In this case, it is preferable to blend so that the content of the hollow filler in the silicone rubber composition for a fixing roller is 10% to 80%, particularly 15% to 75% by volume. If the volume ratio is too small, the decrease in thermal conductivity tends to be insufficient, and if it is too large, molding and blending are difficult, and the molded product may be brittle without rubber elasticity.

  Alternatively, for example, the silicone rubber heat insulating layer 32 may be formed by a method of adding a water-absorbing polymer and water. Examples of the silicone rubber composition include 100 parts by mass of an organopolysiloxane composition, 0.1 to 50.0 parts by mass of a water-absorbing polymer, 10 to 200 parts by mass of water, and other platinum compound catalysts. To form a composition to which a curing catalyst such as SiH and a crosslinking agent such as SiH polymer are added. Thereafter, this may be thermoformed to form the heat insulating elastic layer 32.

  In this case, heating is performed in the following three or two stages. That is, in the first stage, the silicone base polymer is not substantially cured and does not evaporate, and is heated at 100 ° C. or lower, preferably 50 ° C. or higher and 80 ° C. or lower for 10 hours to 30 hours. Mold. Next, in the second stage, the mold product is heated at 120 ° C. or higher and 250 ° C. or lower, preferably 120 ° C. or higher and 180 ° C. or lower for 1 to 5 hours, in the contained water and impurities containing water. Evaporate moisture. And in the final third stage, the obtained porous body is heated at 180 ° C. or higher and 300 ° C. or lower, preferably 200 ° C. or higher and 250 ° C. or lower for 2 to 8 hours to advance the curing, thereby achieving the desired porous property. A silicone rubber layer of a rubbery elastic body is completed.

  Therefore, it is desirable that the heat insulating elastic layer 32 is formed of a liquid silicone composition mainly composed of a balloon such as a microballoon or an organopolysiloxane containing a water-absorbing polymer. The heat insulating elastic layer thus obtained is superior in heat insulation and durability and has less thermal expansion than the sponge silicone rubber heat insulating layer or the solid rubber heat insulating layer.

  Next, the heat storage layer 33 formed on the outer periphery of the heat insulating elastic layer 32 will be described. The heat storage layer 33 is a solid rubber layer in which a layer in which a powdery heat conductive filler (hereinafter also simply referred to as “filler”) is mixed with, for example, silicone rubber or fluororubber is formed on the heat insulating elastic layer 32. It is mentioned as a suitable form. It is preferable for the heat storage layer to have the above configuration because the amount of heat applied to the heat storage layer via the release layer diffuses quickly throughout the heat storage layer.

  It is important that the thermal conductivity of the heat storage layer is higher than that of the heat insulating elastic layer 32. Preferably, the thermal conductivity is higher than that of general solid rubber, and it is desirable to set it to 0.30 W / m · K or more.

  By making the thermal conductivity of the internal heat insulating layer lower than the thermal conductivity of the heat storage layer, the heat transferred from the surface of the fixing roller is unevenly distributed in the heat storage layer near the surface, and is easily maintained. Further, by increasing the thermal conductivity of the heat storage layer, heat can be absorbed and released in the heat storage layer quickly.

  It is desirable that the heat storage layer 33 is formed with a thickness of 50.0 μm or more and 500.0 μm or less.

  The heat storage layer 33 in which the filler is dispersed and the heat capacity is increased has elasticity while having elasticity. For this reason, when the heat storage layer exceeds 500.0 μm, the surface of the fixing roller becomes hard and the adhesion to the recording material is deteriorated. Therefore, there is a tendency that heat transfer is difficult to occur, and problems such as a low temperature offset occur.

  Further, if the heat storage layer is less than 50.0 μm, it is difficult to uniformly disperse the filler and obtain a uniform heat capacity and thermal conductivity. In addition, the heat applied to the magnetic toner on the recording material is unevenly applied, and the amount of heat applied to the toner is uneven. Therefore, the toner is hardly fused and the low-temperature fixability is easily impaired.

  In the present invention, it is also preferable that the heat conductive filler is contained in an amount of 7 parts by mass to 60 parts by mass with respect to 100 parts by mass of the rubber forming the heat storage layer. When the mixing amount of the heat conductive filler is less than 7 parts by mass, the heat capacity of the heat storage layer is small and the low-temperature fixability tends to be inferior. On the other hand, if it exceeds 60 parts by mass, the heat capacity of the heat storage layer becomes excessive, so that the temperature rise rate for the same amount of heat is reduced, so that the warm-up time is extended and the on-demand property tends to be impaired.

  The heat storage layer 33 is formed by the following method, for example, but does not limit the present invention. In particular, a solid rubber layer in which a layer in which 7 to 60 parts by mass of a powdery heat conductive filler is mixed in silicone rubber or fluororubber is formed on the heat insulating elastic layer 32 is preferable.

  Any method can be used as the method for producing the heat storage layer of the present invention. For example, methods such as dipping coating, spray coating, and ring coating in which a liquid resin is coated and formed using a cylindrical coating head around a cylindrical core metal. In particular, ring coating can be preferably used because the heat storage layer can be uniformly applied.

  FIG. 3 shows an example of a ring coating apparatus. A column 72 is vertically mounted on the gantry 71, and a precision ball screw 73 is vertically mounted on the gantry 71 and the column 72. Two linear guides 84 are attached to the column 72 in parallel with the precision ball screw 73. The LM guide 74 is connected to a linear guide 84 and a precision ball screw 73 so that a rotary motion is transmitted from a servo motor 75 via a pulley 76 so that the LM guide 74 can be raised and lowered. A ring-shaped coating head 78 for discharging the coating liquid is attached to the column 72 on the outer peripheral surface of the cylindrical core body 85. Further, the bracket 7 is mounted on the LM guide 74, and a workpiece lower holder 79 that holds and fixes the core body 85 is vertically mounted on the bracket 77, and the workpiece upper holder that holds the opposite core body 85. A central axis 80 is attached to the upper portion of the bracket 77, and the work upper holding tool is disposed so as to be concentric with the work lower holding tool 79 and holds the core body 85.

  The center axis of the ring-shaped coating head 78 is supported so as to be parallel to the moving direction of the workpiece lower holder 79 and the workpiece upper holder 80. Further, when the workpiece lower holder 79 and the workpiece upper fixture 80 are moved up and down, the center axis of the discharge port that is an annular slit opened inside the coating head 78, the workpiece lower holder 79, and the workpiece upper holder are held. The center axis of the tool 80 is adjusted to be concentric. With such a configuration, the central axis of the discharge port formed as an annular slit of the coating head 78 can be aligned with the central axis of the core body 85, and the inner peripheral surface of the ring-shaped coating head and the core body A uniform gap is formed between the outer peripheral surface of 85.

  The coating solution supply port 81 is connected to a material supply valve 83 via a coating solution conveying pipe 82. The material supply valve 83 includes a mixing mixer, a material supply pump, a material fixed amount discharge device, a material tank, and the like in front of the material supply valve 83, and can discharge a fixed amount (a constant amount per unit time) of the coating liquid.

  In order to keep the temperature in the circumferential direction constant in the process of semi-curing the unvulcanized liquid rubber formed on the outer periphery of the core body and the process of curing and bonding the semi-cured liquid rubber and the resin liquid after application lamination It is preferable to use a method of heating while rotating the rubber roller. As the heat source, a far-infrared ceramic heater, a near-infrared heater, a lamp heater, a UV heater, a micro heater, or the like that can heat the rubber roller without contact is desirable.

  A plurality of these heat sources are arranged at regular intervals in the longitudinal direction of the rubber roller in order to continuously change the heating temperature from both ends of the rubber roller toward the center. The number of heat sources is appropriately determined according to the heating temperature change pattern in the longitudinal direction of the rubber roller, but as the number increases, the temperature change in the longitudinal direction of the rubber roller can be controlled delicately and accurately. It becomes possible.

  The heat storage layer contains a powdery heat conductive filler containing at least an aluminum element and / or a zinc element. As long as the requirements of the present invention are satisfied, for example, alumina, zinc oxide, aluminum nitride, zinc nitride, metal aluminum, metal zinc, aluminum-containing alloy, zinc other than aluminum element and / or zinc element heat conductive filler It may contain a powdery heat conductive filler such as a contained alloy.

  In the present invention, it is preferable that Rz on the surface of the image heating member is 2.0 μm or more and 20.0 μm or less. More preferably, Rz is 5.0 μm or more and 15.0 μm or less. When Rz is 2.0 μm or more and 20.0 μm or less, the specific surface area of the surface of the image heating member increases, and heat can be efficiently stored in the image heating member during heating from the outside. Moreover, since the unevenness | corrugation exists moderately, mold release property can be improved, maintaining the outstanding heat conductivity.

  It is not preferred that the Rz on the surface of the image heating member is less than 2.0 μm because the contact area between the toner and the image heating device becomes large and the low temperature offset tends to deteriorate. On the other hand, when the Rz on the surface of the image heating member is larger than 20.0 μm, the unevenness on the surface of the image heating member becomes too large, so that it becomes difficult for heat to be applied uniformly to the toner, and it is difficult for the toner to fuse with each other. Fixability is inferior.

  As a method of controlling Rz, a method of mechanically polishing the surface can be mentioned. As the surface roughening method, a known polishing method such as polishing particles or polishing by adhering the abrasive particles to a tape or paper and pressing it can be used. Further, a sand blasting method in which abrasive particles are hit against the surface can be used. Among these, when polishing is performed using polishing paper, the control of Rz is easy and can be preferably used.

  The image heating member of the present invention preferably has a configuration that can quickly apply heat to the recording material after receiving the amount of heat from the heater. Therefore, it is desirable that the fixing roller 30 has a small diameter, and the outer diameter is preferably in the range of 5 mm to 20 mm.

  In the present invention, the magnetic toner preferably contains 0.2 to 1.0 part by mass of a crosslinking agent with respect to 100 parts by mass of the binder resin. In this case, moderate crosslinking of the binder resin is easily obtained, the low-temperature fixability is not impaired, and the image density stability during long-term durability is excellent.

  Here, as the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate, ethylene Carboxylic acid esters having two double bonds such as glycol dimethacrylate, 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinylsulfone; and three or more vinyl groups Are used alone or as a mixture.

  In the present invention, the average circularity of the toner is preferably 0.960 or more. It is considered that the spherical toner is densely packed on a medium such as paper. In the fixing process, the toner is not only anchored to the paper but also fused with other toner particles, which is also an important factor, and is advantageous because it is a spherical toner that is closely packed. It is considered that the fixability is very good due to a synergistic effect with the volume expansion of the toner. In the toner circularity distribution, the mode circularity is preferably 0.98 or more. The mode circularity of 0.98 or more means that most of the toner particles have a shape close to a true sphere, and the above action is more remarkable, which is preferable.

  When one melting point of the release agent compatible with the binder resin contained in the toner is Tm1 [° C.] and one melting point of the release agent incompatible with the binder resin is Tm2 [° C.] Tm1 is preferably 50 ° C. or higher and Tm1 ≦ Tm2 + 10. More preferably, Tm1 ≦ Tm2. In this condition range, the compatible release agent is first dissolved in the toner at the time of fixing, so that the incompatible release agent is pushed out from the inside to the toner surface. Thus, it is thought that the toner is rapidly deformed by promoting the bleeding of the compatible release agent and having a liquid core structure, and good low-temperature fixability can be obtained.

  Tm1 and Tm2 are the peak top temperatures of the compatible release agent and the incompatible release agent in the differential scanning calorimeter (DSC) measurement, and the measurement of the peak top temperature of each endothermic peak is as follows: Performed according to “ATSM D 3417-99”.

  The toner of the present invention may further contain a release agent (other release agents) that does not satisfy the relationship of Tm1 ≦ Tm2 + 10. Higher melting point release agents can improve the high temperature offset of the toner.

  The content of the release agent in the toner of the present invention is such that the release agent compatible with the binder resin is 2 to 30 parts by mass with respect to 100 parts by mass of the binder resin, and is incompatible with the binder resin. It is preferable that the amount of the release agent is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin, in addition to excellent low-temperature fixability and occurrence of fixing roller contamination.

  Specific examples of the release agent contained in the toner of the present invention include petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof; montan wax and derivatives thereof; hydrocarbon waxes and derivatives thereof according to the Fischer-Tropsch method Polyolefin waxes represented by polyethylene and derivatives thereof; natural waxes and derivatives thereof such as carnauba wax and candelilla wax; and fatty acids such as higher aliphatic alcohols, stearic acid and palmitic acid, or compounds thereof; acid amide waxes; Ester wax; ketone; hydrogenated castor oil and derivatives thereof; plant wax; animal wax and the like.

  Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products.

  From these release agents, one or more release agents compatible with the binder resin and one or more incompatible release agents are selected.

  The toner of the present invention may contain at least two release agents satisfying the relationship of Tm1 ≦ Tm2 + 10. In addition to this, a release agent having a low melting point for improving the plasticity of the binder resin, In order to improve the high temperature offset, it is possible to use a release agent having a high melting point, and the release agent used in combination may be used alone or in combination.

  The incompatible release agent in the present invention refers to a release agent having a solubility in styrene-acrylic resin of less than 3% and a solubility in styrene monomer of less than 5%.

  In the present invention, it is preferable to use crystalline polyester as a release agent incompatible with the binder resin. Crystalline polyester has high crystallinity, so it is hardly compatible with the binder resin, and the above-described volume expansion effect is easily obtained. In addition, crystalline polyester has a sharp melting point peak in differential scanning calorimetry (DSC) measurement, and takes a liquid core structure in the toner instantly with heat during fixing, so the extrusion effect of the release agent is stronger. can get.

  The crystalline polyester contained in the toner of the present invention is not particularly limited, but is preferably a “polycondensate of a linear dicarboxylic acid and a linear aliphatic dialcohol”, and the linear dicarboxylic acid and A polyester structural unit derived from a linear aliphatic dialcohol is preferred.

  The terminal of the crystalline polyester in the present invention may be capped with a monocarboxylic acid or the like. Further, if the main structural unit is a polyester structural unit derived from a linear dicarboxylic acid and a linear aliphatic dialcohol, it may contain a polyester structural unit derived from a polyvalent carboxylic acid. Polyester structural units derived from polyvalent carboxylic acids can increase the acid value of the polyester.

  The crystalline polyester in the present invention can be produced according to a normal polyester synthesis method by appropriately selecting its monomer components (alcohol component and carboxylic acid component).

  For example, a dicarboxylic acid component and a dial alcohol component are esterified or transesterified, and then subjected to a polycondensation reaction under a reduced pressure or a nitrogen gas atmosphere according to a conventional method to obtain a crystalline polyester.

  The esterification reaction or transesterification reaction is carried out using a normal esterification catalyst or transesterification catalyst as necessary. Examples of esterification catalysts or transesterification catalysts include sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate, magnesium acetate and the like.

  The polycondensation reaction can be performed using a normal polycondensation catalyst. Examples of the polycondensation catalyst include known ones such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide and the like. The polymerization temperature and the amount of catalyst are not particularly limited, and may be arbitrarily selected as necessary.

  As described above, the crystalline polyester in the present invention can be produced by a polycondensation reaction between an alcohol monomer and a carboxylic acid monomer.

  The main component of the alcohol monomer to be polycondensed is preferably a linear aliphatic dialcohol monomer.

  Examples of linear aliphatic dialcohol monomers include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol , Pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, neopentyl glycol, 1,4-butadiene glycol and the like.

  The main component of the alcohol monomer to be polycondensed is preferably the linear aliphatic dialcohol monomer, but polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, 1,4- Branched chain dialcohols such as cyclohexanedimethanol; aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2 , 5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trivalent alcohols such as trimethylolethane and trimethylolpropane;

  Moreover, it is preferable that the main component of the carboxylic acid monomer polycondensed to obtain the crystalline polyester in the present invention is a linear dicarboxylic acid.

  Examples of linear dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, peric acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid Examples include acids, dodecanedicarboxylic acids, anhydrides of these acids, and lower alkyl esters.

  The main component of the carboxylic acid monomer to be polycondensed is preferably composed of the linear dicarboxylic acid as a main component, but may contain a non-linear dicarboxylic acid.

  Examples of the non-linear dicarboxylic acid include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, isophthalic acid, terephthalic acid, and anhydrides or lower alkyl esters of these acids.

  The main component of the carboxylic acid monomer to be polycondensed is preferably composed of the linear dicarboxylic acid as a main component, but may further contain a trivalent or higher polyvalent carboxylic acid. Examples of trivalent or higher polyvalent carboxylic acids include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, pyromellitic acid, 1,2,4-butanetricarboxylic acid. 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, derivatives of these acid anhydrides or lower alkyl esters, and the like.

  In the present invention, the acid value of the crystalline polyester is preferably 5 mgKOH / g or less. If the amount is 5 mgKOH / g or less, when the toner is produced by a suspension polymerization method (described later), which is a preferred method for producing the toner of the present invention, the crystalline polyester is easily introduced into the toner, and the toner extrusion described above is performed. It is excellent in low temperature fixability due to the effect and is preferable. Further, since the acid value is low and it is difficult to absorb moisture, it is preferable because development stability during long-term use is easily obtained.

  In the present invention, in the differential scanning calorimeter (DSC) measurement, the crystalline polyester preferably has an endothermic peak at 60 to 90 ° C. Within this range, the low-temperature fixability is not impaired, and the density is not lowered during long-term use. In addition, the toner is preferably produced by a suspension polymerization method (described later), which is a preferred toner production method in the present invention, which is excellent in solubility in a polymerizable monomer and easily dispersible in the toner.

  The number average molecular weight of the crystalline polyester is preferably 2000 or more and 7000 or less. Within this range, the crystalline polyester is unlikely to be compatible with the binder resin during the production of the toner, and the crystallinity is easily maintained in the toner. Thereby, it becomes easy to bring out the above-mentioned extrusion effect, and it is excellent in low-temperature fixability and preferable.

  In the present invention, the crystalline polyester refers to a polyester having an endothermic peak at the time of temperature rise in the differential scanning calorimeter (DSC) measurement and an exothermic peak at the time of temperature fall, and the measurement is in accordance with the “ASTM D 3417-99” measurement method. Do it.

  In the present invention, a charge control agent may be used, and any known charge control agent can be used without any particular limitation. Among these, a charge control agent that has a particularly high charging speed and can stably maintain a constant charge amount is preferable.

  Further, when the toner is produced using a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. Specific examples of negative charge control agents include metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, and dicarboxylic acid, and organic metals such as metal salts or metal complexes of azo dyes or azo pigments. Compounds: boron compounds, urea compounds, silicon compounds, calixarene and the like. Examples of positive charge control agents include quaternary ammonium salts, guanidine compounds, nigrosine compounds, and imidazole compounds.

  As a method of adding a charge control agent to the toner, a method of adding the toner inside the toner particles, and suspension polymerization, when forming oil droplets in water, or forming oil droplets in water, A method of adding during polymerization is general, or seed polymerization can be performed by adding a polymerizable monomer in which a charge control agent is dissolved and suspended after polymerization. In the case of using an organometallic compound as a charge control agent, it is also possible to introduce these compounds by adding them externally to the toner particles, applying a shear and mixing and stirring.

  The amount of these charge control agents used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely limited. When adding internally, it is preferable to use 0.01 mass part or more and 10 mass parts or less with respect to 100 mass parts of binder resin. However, the developer related to the image forming method of the present invention does not require the addition of a charge control agent, and the toner can be applied to the toner by actively utilizing the frictional charging of the developer with the layer pressure regulating member or the developer carrier. If sufficient chargeability can be imparted, it is not always necessary to include a charge control agent in the toner.

  The magnetic body of the present invention preferably uses 20 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the binder resin. If it is this range, it is excellent also in suppression of coloring power and fog, and can be used without impairing low-temperature fixability.

  Note that the content of the magnetic substance in the toner can be measured using a thermal analyzer, TGA7, manufactured by PerkinElmer. In the measurement method, the toner is heated from room temperature to 900 ° C. at a temperature rising rate of 25 ° C./min in a nitrogen atmosphere, and the weight loss part between 100 ° C. and 750 ° C. is defined as the binder resin amount, and the remaining weight is approximated. The amount of magnetic material.

  When the toner is produced using the polymerization method in the present invention, it is necessary to pay attention to the aqueous phase migration of the magnetic material. Preferably, the toner is subjected to surface modification, for example, a hydrophobic treatment with a substance that does not inhibit polymerization. It ’s better to leave it.

The magnetic powder of the present invention is mainly composed of iron oxide such as triiron tetroxide and γ-iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. Good. These magnetic materials preferably have a BET specific surface area of 2 m ² / g or more and 30 m ² / g or less, more preferably 3 m ² / g or more and 28 m ² / g or less by a nitrogen adsorption method. Further, those having a Mohs hardness of 5 or more and 7 or less are preferable. The shape of the magnetic body includes a polyhedron, an octahedron, a hexahedron, a sphere, a needle, a scale, and the like, but a polyhedron, an octahedron, a hexahedron, a sphere, and the like having low anisotropy increase the image density. Is preferable.

  Next, the average particle size of the magnetic material is preferably 0.10 μm or more and 0.40 μm or less. In general, the smaller the particle size of the magnetic material, the higher the coloring power, but the magnetic material tends to aggregate, and the uniform dispersibility of the magnetic material in the toner is inferior. On the other hand, when the particle size is 0.10 μm or less, the magnetic material itself becomes reddish black, so that the image becomes particularly conspicuous in red in a halftone image, which is not preferable because it cannot be said to be a high-quality image.

  On the other hand, when the average particle size is 0.40 μm or more, the coloring power of the toner is insufficient, and in the suspension polymerization method (described later) which is a preferable method for producing the toner, uniform dispersion becomes difficult, which is not preferable.

  The volume average particle diameter of the magnetic material can be measured using a transmission electron microscope. Specifically, after sufficiently dispersing toner particles to be observed in an epoxy resin, a cured product obtained by curing for 2 days in an atmosphere at a temperature of 40 ° C. is used as a sample on a thin piece by a microtome. In an electron microscope (TEM), 100 magnetic particle diameters in the field of view are measured with a photograph with an enlargement magnification of 10,000 to 40,000 times. Then, the volume average particle diameter is calculated based on the equivalent diameter of a circle equal to the projected area of the magnetic material. It is also possible to measure the particle size with an image analyzer.

  The magnetic material used in the toner of the present invention can be produced, for example, by the following method.

  An aqueous solution containing ferrous hydroxide is prepared by adding an alkali such as sodium hydroxide to the ferrous salt aqueous solution in an amount equivalent to or greater than the iron component. Air was blown in while maintaining the pH of the prepared aqueous solution at pH 7 or higher, and ferrous hydroxide was oxidized while heating the aqueous solution to 70 ° C. or higher. First, seed crystals serving as the core of the magnetic iron oxide powder were formed. Generate.

  Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. While maintaining the pH of the solution at 5 or more and 10 or less, the ferrous hydroxide reaction is promoted while blowing air, and the magnetic iron oxide powder is grown with the seed crystal as the core. At this time, it is possible to control the shape and magnetic characteristics of the magnetic material by selecting an arbitrary pH, reaction temperature, and stirring conditions. As the oxidation reaction proceeds, the pH of the liquid shifts to the acidic side, but the pH of the liquid is preferably not less than 5. The magnetic material thus obtained can be obtained by filtering, washing and drying by a conventional method.

  In the present invention, when a toner is produced by a polymerization method, it is very preferable to subject the surface of the magnetic material to a hydrophobic treatment. When surface treatment is performed in a dry process, the coupling agent treatment is performed on the magnetic material that has been washed, filtered, and dried. In the case of wet surface treatment, after the oxidation reaction is finished, re-disperse the dried one, or after the oxidation reaction is finished, wash and filter the iron oxide body obtained in another aqueous medium without drying. And re-disperse to pH, make the pH of the re-dispersed liquid acidic, add silane coupling agent with sufficient stirring, raise the temperature after hydrolysis, or perform the coupling treatment by raising the pH to alkaline You can also. Among these, from the viewpoint of performing a uniform surface treatment, it is preferable to perform the surface treatment by reslurry as it is without drying after filtration and washing after completion of the oxidation reaction.

  In order to treat the surface of the magnetic material with a wet type, that is, with a coupling agent in an aqueous medium, first, sufficiently disperse the magnetic substance in the aqueous medium so as to have a primary particle size, and a stirring blade or the like so as not to settle or aggregate. Stir with. Next, an arbitrary amount of the coupling agent is added and the surface treatment is performed while hydrolyzing the coupling agent. At this time, the surface treatment is performed while sufficiently dispersing so as not to aggregate while using a device such as a pin mill or a line mill while stirring. More preferably.

  Here, the aqueous medium is a medium containing water as a main component. Specific examples include water itself, water added with a small amount of surfactant, water added with a pH adjuster, and water added with an organic solvent. As the surfactant, a nonionic surfactant such as polyvinyl alcohol is preferable. The surfactant is preferably added in an amount of 0.1 to 5.0 parts by mass with respect to water. Examples of the pH adjuster include inorganic acids such as hydrochloric acid. Examples of the organic solvent include alcohols.

  Examples of the coupling agent that can be used in the surface treatment of the magnetic material according to the present invention include a silane coupling agent and a titanium coupling agent. More preferably used are silane coupling agents, which are represented by the general formula (a).

RmSiYn (A)
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, or a methacryl group, and n represents an integer of 1 to 3. Show. However, m + n = 4. ]
Examples of the silane coupling agent represented by the general formula (A) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, Vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyl Diethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-decyltrimethoxysilane, hydroxypropyltrimethoxysilane, n-hexadecyltrimethoxysilane, n- Examples include octadecyltrimethoxysilane.

Among these, from the viewpoint of obtaining high hydrophobicity, it is preferable to use an alkyltrialkoxysilane coupling agent represented by the following general formula (I).
C _p H _{2p + 1} —Si— (OC _q H _{2q + 1} ) ₃ (A)
[Wherein, p represents an integer of 2 or more and 20 or less, and q represents an integer of 1 or more and 3 or less. ]

  When p in the above formula is smaller than 2, it is difficult to sufficiently impart hydrophobicity, and when p is larger than 20, the hydrophobicity is sufficient, but the coalescence of the magnetic materials increases, which is not preferable. .

  Further, when q is larger than 3, the reactivity of the silane coupling agent is lowered and the hydrophobicity is not sufficiently performed. Therefore, p in the formula is an integer of 2 or more and 20 or less (more preferably, 1 or more and 15 or less). It is preferable to use an alkyltrialkoxysilane coupling agent in which q is an integer of 1 or more and 3 or less (more preferably, an integer of 1 or 2).

  When using the above silane coupling agent, it is possible to treat it alone or in combination with a plurality of types. When used together, each coupling agent is treated individually or simultaneously. I can do it.

  The total amount of coupling agent to be used is preferably 0.9 to 3.0 parts by mass with respect to 100 parts by mass of the magnetic material, and is treated according to the surface area of the magnetic material, the reactivity of the coupling agent, etc. It is important to adjust the amount of agent.

  In the present invention, other colorants may be used in addition to the magnetic substance. Examples of the colorant that can be used in combination include magnetic or nonmagnetic inorganic compounds and known dyes and pigments. Specifically, for example, ferromagnetic metal particles such as cobalt and nickel, or alloys obtained by adding chromium, manganese, copper, zinc, aluminum and rare earth elements to these, particles such as hematite, titanium black, nigrosine dye / pigment , Carbon black, phthalocyanine and the like. These are also preferably used by treating the surface.

  The toner of the present invention can be produced by any known method. First, in the case of producing by a pulverization method, for example, components necessary as a toner such as a binder resin, a release agent, and a magnetic material, a charge control agent, and other additives are mixed with a mixer such as a Henschel mixer or a ball mill. After mixing well, melt and knead using a heat kneader such as a heating roll, kneader, extruder to disperse or dissolve the toner material, cool and solidify, grind, classify, and perform surface treatment as necessary Particles can be obtained. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

  The pulverization step can be performed by a method using a known pulverizer such as a mechanical impact type or a jet type. In order to obtain a toner having an average circularity of 0.960, which is preferably used in the present invention, it can be achieved by further pulverizing with heat, or by subjecting it to an auxiliary mechanical impact treatment. is there.

  Examples of means for applying mechanical impact force include a method using a mechanical impact type pulverizer such as a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. There is a method of applying a mechanical impact force to the toner by a force such as a compressive force or a frictional force by pressing the toner against the inside of the casing by a centrifugal force with a blade rotating at high speed, as in a device such as a hybridization system manufactured by the manufacturer.

  In the case of using the mechanical impact method, a thermomechanical impact in which the processing temperature is a temperature in the vicinity of the glass transition point Tg (Tg ± 10 ° C.) of the toner is preferable from the viewpoint of preventing aggregation and productivity.

  As a binder resin when the toner according to the present invention is produced by a pulverization method, styrene such as polystyrene and polyvinyltoluene and a homopolymer of a substituted product thereof; a styrene-propylene copolymer, a styrene-vinyltoluene copolymer, Styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylamino acrylate Ethyl copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinylmethyl Ether copolymer, styrene-vinylethyl Styrene copolymer such as ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin can be used, and these can be used alone or in combination I can do it. Of these, styrene copolymers and polyester resins are particularly preferred from the standpoints of development characteristics and fixability.

  The toner of the present invention can be produced by a pulverization method as described above, but the toner particles obtained by this pulverization method are generally indefinite. In order to obtain the physical property of an average circularity of 0.960 or more preferably used in the present invention, it is necessary to perform the mechanical / thermal or some special treatment as described above, resulting in poor productivity. Therefore, the toner of the present invention is preferably produced in a wet medium such as a dispersion polymerization method, an association aggregation method, a suspension polymerization method, etc. In particular, the suspension polymerization method is very easy to satisfy the suitable physical properties of the present invention. preferable.

  In the suspension polymerization method, a polymerizable monomer and a colorant (in addition, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives as necessary) are uniformly dissolved or dispersed to form a polymerizable monomer. After preparing the composition, the polymerizable monomer composition is dispersed in a continuous layer containing a dispersion stabilizer (for example, an aqueous phase) using a suitable stirrer, and simultaneously subjected to a polymerization reaction to obtain a desired particle size. A toner having the above is obtained. The toner obtained by this suspension polymerization method (hereinafter referred to as polymerized toner) is easy to obtain a toner having an average circularity of 0.960 or more because the individual toner particle shapes are substantially spherical. Furthermore, since the toner has a relatively uniform charge amount distribution, an improvement in image quality can be expected.

  Next, a production method by a suspension polymerization method suitable for the production of the toner of the present invention will be described. The polymerized toner according to the present invention includes a toner such as a release agent, a magnetic substance, and a plasticizer, a charge control agent, a crosslinking agent, a colorant, etc. in a polymerizable monomer that becomes a binder resin. As necessary components and other additives, for example, a polymeric polymer such as amorphous polyester, a dispersing agent, etc. are added as appropriate, and the polymerizable monomer composition is uniformly dissolved or dispersed by a disperser etc. Can be prepared by suspending it in an aqueous medium containing a dispersion stabilizer. In the production of the polymerized toner of the present invention, examples of the polymerizable monomer constituting the polymerizable monomer composition include the following.

  Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, methyl acrylate, ethyl acrylate, Acrylate esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate , Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Methacrylic acid dimethyl aminoethyl, methacrylic acid esters other acrylonitrile such as diethylaminoethyl methacrylate, methacrylonitrile, and the like monomers acrylamide. These monomers can be used alone or in combination. Among the above-mentioned monomers, styrene or a styrene derivative is preferably used alone or mixed with other monomers from the viewpoint of the developing characteristics and durability of the toner.

  Further, a resin other than those described above may be added to the monomer composition for the purpose of improving the dispersibility and fixing properties of the material or the image characteristics. Examples of the resin used include homopolymers of styrene such as polystyrene and polyvinyltoluene and substituted products thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic. Acid methyl copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate Copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer Polymer, styrene-vinyl Styrene copolymers such as methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate , Polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyamide resin, epoxy resin, polyacrylic acid resin, rosin, modified rosin, temper resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic Petroleum resins can be used alone or in combination. As addition amount of these resin, 1 to 20 mass parts is preferable with respect to 100 mass parts of polymerizable monomers. If it is less than 1 part by mass, the effect of addition is small, and if it is added in excess of 20 parts by mass, it becomes difficult to design various properties of the polymerized toner.

  In the toner of the present invention, conventionally known azo polymerization initiators, peroxide polymerization initiators and the like can be used as the polymerization initiator. As the azo polymerization initiator, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) ), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like. Examples of peroxide polymerization initiators include t-butyl peroxyacetate, t-butyl peroxylaurate, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyate. Oxyisobutyrate, t-butylperoxyneodecanoate, t-hexylperoxyacetate, t-hexylperoxylaurate, t-hexylperoxypivalate, t-hexylperoxy-2-ethylhexanoate , T-hexylperoxyisobutyrate, t-hexylperoxyneodecanoate, t-butylperoxybenzoate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, 2,5-dimethyl-2,5-bis (2-ethyl) Hexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2- Ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxy-m-toluoylbenzoate, bis (t-butylperoxy) iso Phthalate, t-butyl peroximer Peroxyesters such as ic acid, t-butylperoxy-3,5,5-trimethylhexanoate, 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane, benzoyl peroxide, Diacyl peroxide such as lauroyl peroxide, isobutyryl peroxide, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, peroxydicarbonate such as di-sec-butylperoxydicarbonate, 1,1-di-t-butylperoxycyclohexane, 1,1-di-t-hexylperoxycyclohexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,2 -Di-t-butyl peroxybutane, etc. Peroxy ketals, di -t- butyl peroxide, dicumyl peroxide, dialkyl peroxides such as t- butyl cumyl peroxide, other as t- butylperoxy allyl monocarbonate and the like. If necessary, two or more of these initiators can be used.

  In the method for producing the toner of the present invention by a polymerization method, generally a composition containing at least the above-mentioned polymerizable monomer, release agent, and crystalline polyester is appropriately added, and a homogenizer, ball mill, colloid mill, ultrasonic disperser is added. A polymerizable monomer composition uniformly dissolved or dispersed by a dispersing machine such as the like is suspended in an aqueous medium containing a dispersion stabilizer. At this time, it is easier to sharpen the particle size of the obtained toner particles by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size all at once. The polymerization initiator may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. In addition, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  After granulation, stirring may be performed using a normal stirrer to such an extent that the particle state is maintained and particle floating and sedimentation are prevented.

  When the toner of the present invention is produced by a polymerization method, a known surfactant, organic dispersant, or inorganic dispersant can be used as a dispersion stabilizer. In particular, inorganic dispersants are less likely to produce harmful ultrafine powders, and because of their steric hindrance, dispersion stability is obtained, so even if the reaction temperature is changed, stability is not easily lost, and washing is easy and does not adversely affect the toner. Therefore, it can be preferably used. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate, carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate and barium sulfate. Inorganic oxides such as inorganic salts, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite and alumina can be mentioned.

  These inorganic dispersants are preferably used in an amount of 0.2 parts by mass or more and 20 parts by mass or less alone or in combination of two or more with respect to 100 parts by mass of the polymerizable monomer. Furthermore, you may use together 0.001 mass part or more and 0.1 mass part or less surfactant.

  When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated in an aqueous medium. For example, in the case of calcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed under high-speed stirring to produce water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At the same time, water-soluble sodium chloride is by-produced. However, if a water-soluble salt is present in the aqueous medium, dissolution of the polymerizable monomer in water is suppressed, and ultrafine toner is generated by emulsion polymerization. This is more convenient. The inorganic dispersant can be almost completely removed by dissolution with an acid or an alkali after completion of the polymerization.

  Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.

  In the polymerization step, the polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 ° C. or higher and 90 ° C. or lower. When the polymerization is carried out in this temperature range, the release agent to be sealed inside is precipitated by phase separation, and the encapsulation becomes more complete. Moreover, it is preferable to raise the reaction temperature to the melting point of the release agent incompatible with the binder resin when the conversion rate of the polymerizable monomer is 50% or more and 100% or less. This is considered that when a toner is produced by a suspension polymerization method, the incompatible release agent forms a domain inside the toner particles or exists in a finely dispersed state. Therefore, by raising the temperature above the melting point of the incompatible release agent, the release agent finely dispersed in the toner forms a proper domain, and the volume expansion effect described so far is exhibited. As a result, good low-temperature fixability can be obtained. The same applies to the case where crystalline polyester is used. With respect to crystalline polyesters, crystalline polyesters that could not form neat crystals during polymerization of the polymerizable monomer can also be raised in crystallinity by raising the temperature to the melting point or higher, and toner deterioration even during long-term use. It becomes difficult to occur.

  After the polymerization is completed, the polymerized toner particles are filtered, washed and dried by a known method, and if necessary, inorganic fine powder is mixed and adhered to the surface, whereby the toner of the present invention can be obtained. It is also possible to put a classification step into the manufacturing process and cut coarse powder and fine powder.

  Further, in the present invention, it is also a preferred form that the toner is added with an inorganic fine powder having a number average primary particle size of 4 nm or more and 80 nm or less, more preferably 6 nm or more and 40 nm or less as a fluidizing agent. The inorganic fine powder is added to improve the fluidity of the toner and to make the charge of the toner particles uniform. However, adjustment of the charge amount of the toner, improvement of environmental stability, etc. by treatment such as hydrophobizing the inorganic fine powder. It is also a preferable form to provide the function.

  When the number average primary particle size of the inorganic fine powder is larger than 80 nm, or when the inorganic fine powder of 80 nm or less is not added, good toner fluidity cannot be obtained. For this reason, the charging of toner particles is likely to be uneven, and problems such as an increase in fog, a decrease in image density, and an increase in consumption are unavoidable. On the other hand, when the number average primary particle size of the inorganic fine powder is smaller than 4 nm, the fineness of the inorganic fine powder becomes stronger, and the particle size distribution has strong cohesiveness that is difficult to break even by crushing treatment instead of the primary particles. It tends to behave as a wide aggregate. For this reason, image defects due to development of the aggregate, damage to the image carrier or magnetic toner carrier, etc. are likely to occur, which is not preferable.

  In the present invention, the number average primary particle size of the inorganic fine powder is measured by a photograph of the toner magnified by a scanning electron microscope, and further by an elemental analysis means such as XMA attached to the scanning electron microscope. 100 or more primary particles of inorganic fine powder adhering to or liberating from the toner surface were measured while comparing photographs of the toner mapped with the elements contained in the body, and the average primary particles based on the number It can be measured by determining the diameter and number average primary particle size.

Silica, titanium oxide, alumina, etc. can be used as the inorganic fine powder used in the present invention. As the silicate fine powder, for example, both a so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass can be used. However, dry silica having less silanol groups on the surface and inside the silica fine powder and less production residue such as Na ₂ O and SO ₃ ²⁻ is more preferable. In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

  The addition amount of the inorganic fine powder having a number average primary particle size of 4 nm or more and 80 nm or less is preferably 0.1 parts by mass or more and 3.0 parts by mass or less with respect to the toner particles. If the addition amount is less than 0.1 parts by mass, the effect is not sufficient, and if it exceeds 3.0 parts by mass, the fixability is deteriorated.

  Further, the content of the inorganic fine powder can be quantified using a calibration curve prepared from a standard sample using fluorescent X-ray analysis.

  In the present invention, the inorganic fine powder is preferably a hydrophobized product because environmental stability is improved. When the inorganic fine powder added to the toner absorbs moisture, the charge amount of the toner particles is remarkably reduced, the charge amount is likely to be non-uniform, and toner scattering is likely to occur.

  As the treating agent used for the hydrophobizing treatment, treating agents such as silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds may be used alone or You may process together.

  Among them, those treated with silicone oil are preferable, and more preferably, the inorganic particles are hydrophobized with a silane compound, or are treated with silicone oil and then treated with silicone oil, even in a high humidity environment. In order to prevent toner scattering.

  As a method for treating such inorganic fine powder, for example, as a first-stage reaction, a silanization reaction is performed with a silane compound, silanol groups are eliminated by chemical bonds, and then a hydrophobic reaction is performed on the surface with silicone oil as a second-stage reaction. The thin film can be formed.

The silicone oil may have a viscosity less of 10 mm ² / s or more 200,000 mm ² / s at 25 ° C., and more preferably the following 3,000 mm ² / s or more 80,000mm ² / s. If it is less than 10 mm ² / s, the inorganic fine powder is not stable and the image quality tends to deteriorate due to heat and mechanical stress. If it exceeds 200,000 mm ² / s, uniform processing tends to be difficult.

  As the silicone oil used, for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are particularly preferable.

  As a method for treating the inorganic fine powder with silicone oil, for example, the inorganic fine powder treated with the silane compound and the silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the inorganic fine powder may be mixed with the inorganic fine powder. A method of spraying silicone oil may be used. Alternatively, after dissolving or dispersing silicone oil in an appropriate solvent, inorganic fine powder may be added and mixed to remove the solvent. A method using a sprayer is more preferable in that the formation of inorganic fine powder aggregates is relatively small.

  The treatment amount of the silicone oil is 1 to 40 parts by mass, preferably 3 to 35 parts by mass with respect to 100 parts by mass of the inorganic fine powder. If the amount of silicone oil is too small, good hydrophobicity cannot be obtained, and if it is too large, problems such as fogging tend to occur.

The inorganic fine powder used in the present invention preferably has a specific surface area of 20 m ² / g or more and 350 m ² / g or less measured by the BET method by nitrogen adsorption in order to impart good fluidity to the toner. More preferably, those of 25 m ² / g or more and 300 m ² / g or less are even better.

  In accordance with the BET method, the specific surface area is obtained by adsorbing nitrogen gas to the sample surface using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics) and calculating the specific surface area using the BET multipoint method.

The toner of the present invention further has a primary particle size of more than 30 nm (preferably a specific surface area of less than 50 m ² / g), more preferably a primary particle size of 50 nm or more (preferably a specific surface area of 30 m ² ) for the purpose of improving cleaning properties. It is also one of preferable modes to add inorganic or organic fine particles close to spherical shape (less than / g). For example, spherical silica particles, spherical polymethylsilsesquioxane particles, spherical resin particles and the like are preferably used.

  The toner used in the present invention may further contain other additives, for example, a lubricant powder such as a polyfluorinated ethylene powder, a zinc stearate powder, a polyvinylidene fluoride powder, or a cerium oxide powder within a range that does not substantially adversely affect the toner. Abrasives such as silicon carbide powder and strontium titanate powder, or fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder, anti-caking agents, and organic fine particles having opposite polarity and inorganic fine particles are used as developability improvers. A small amount can also be used. These additives can also be used after hydrophobizing the surface.

  Next, an image forming apparatus for carrying out the image forming method of the present invention will be described.

(1) Example of Image Forming Apparatus FIG. 4 is a schematic cross-sectional view showing a schematic configuration of a laser beam printer (hereinafter abbreviated as a printer) 1 as an example suitably showing the image forming apparatus of the present embodiment.

  Image information is input to the printer 1 from an image information providing device (not shown) such as a host computer provided outside the printer body. The printer 1 performs a series of image forming processes in which an image corresponding to the input image information is formed and recorded on a sheet-like recording material (recording medium) P according to a known electrophotographic system.

  The printer 1 includes a process cartridge 4 that holds a drum-like rotatable electrophotographic photosensitive member (hereinafter abbreviated as a photosensitive member) 2 as a latent image carrier, a primary charging mechanism 8, and a developing device 3. I have. Further, a laser scanner unit (hereinafter abbreviated as “scanner”) 5 for forming an electrostatic latent image corresponding to the image information on the outer peripheral surface of the photoreceptor 2 by an exposure processing step corresponding to the image information input from the image information providing apparatus. It has. Further, a roll-shaped rotatable transfer body 6 that performs a process of transferring an image to the recording material P, and a fixing device 7 as an image heating apparatus that performs a fixing process on the recording material P that has undergone the image transfer process by heating and pressing. It has.

  The process cartridge 4 is detachably supported with respect to the printer body. When maintenance such as repair of the photosensitive member 2 or supply of developer to the developing device 3 is necessary, the maintenance is performed by opening the cover 9 that is supported by the main body so as to be freely opened and closed and then replacing the process cartridge 4 together. Speeding up and simplification.

  The primary charging mechanism 8 is configured to charge the outer peripheral surface of the rotating photosensitive member 2 to a specified potential distribution by applying a specified bias before the exposure processing step by the scanner 5.

  The scanner 5 outputs a laser La corresponding to the image information from the image information providing apparatus. The laser La scans and exposes the charged outer peripheral surface of the photoreceptor 2 through a window 4a provided in the process cartridge body. As a result, an electrostatic latent image corresponding to the image information is formed on the outer peripheral surface of the photoreceptor 2.

  Next, a series of image forming processes in the printer 1 will be described. When the start button or the like (not shown) provided on the printer main body is pressed, the rotation of the photosensitive member 2 is started. The photoreceptor 2 is driven to rotate at a specified peripheral speed in the clockwise direction indicated by the arrow K1. At the same time, the outer peripheral surface of the photoreceptor 2 is charged to a specified potential distribution by the primary charging mechanism 8 to which a specified bias is applied.

  Next, the charged portion of the outer peripheral surface of the photoconductor 2 is scanned and exposed by the scanner 5 in accordance with image information from the image information providing apparatus. Thereby, an electrostatic latent image corresponding to the image information is formed on the portion of the photoreceptor 2. The electrostatic latent image is developed by the developer of the developing device 3 to be visualized as a toner image.

  On the other hand, the recording material P is fed from the paper feed cassette 11 by the paper feed roller 12 driven at a predetermined timing. The recording material P fed from the paper feed cassette 11 is fed to a transfer nip portion formed between the photosensitive member 2 and the transfer member 6 by a registration roller pair 12a at a predetermined control timing, and the transfer nip portion. Is being nipped and conveyed. In this nipping and conveying process, the toner image on the photosensitive member 2 side is sequentially transferred to the recording material P side by the transfer member 6.

  The recording material P that has been subjected to the transfer process is subjected to heat fixing processing of the toner image by the fixing device 7 and then passes through the fixing paper discharge unit 10 that is rotatably supported by the printer main body. 13 is discharged outside the apparatus. The discharged recording material P is stacked on a tray 14 attached to the upper surface of the printer main body. As described above, a series of image forming processes is completed.

(2) Fixing device 7
FIG. 2 is a schematic cross-sectional view of a fixing device 7 that is an example of an external heating type image heating device that suitably illustrates the present embodiment.

  Reference numeral 30 denotes a fixing roller (fixing rotating body) as a rotatable heating member that heats an image on the recording material at the nip portion. Reference numeral 63 denotes a rotatable pressure roller as a pressure member. The pressing member 63 may be a fixed pad.

  The fixing roller 30 and the pressure roller 63 are arranged substantially in parallel in the vertical direction, and are pressed against each other by a pressure spring (not shown) at the end. Thus, a fixing nip portion (pressure nip portion) Nt having a predetermined width is formed between them in the recording material conveyance direction.

  The fixing roller 30 is rotationally driven by a driving means (not shown) in a clockwise direction indicated by an arrow at a predetermined peripheral speed. The pressure roller 63 rotates following the rotation of the fixing roller 30. Note that the fixing roller 30 and the pressure roller 63 may be separately rotated.

  Reference numeral 21 denotes a heating means (heating source) for heating the fixing roller 30 from the outside thereof. In this embodiment, the heating means 21 is a plate heater (hereinafter abbreviated as a heater). The heater 21 is fixedly held on the heater holder 24 and arranged in parallel on the upper side of the fixing roller 30. The holder 24 is pressed with a constant pressure by a pressurizing mechanism (not shown), and the heater 21 is adjusted so as to come into pressure contact with the upper surface of the fixing roller 30 with a predetermined pressure. The heater 21 is always in contact with the fixing roller 30 at the same position, and forms a heating nip portion Nh having a predetermined width in the rotational direction of the fixing roller 30 with the fixing roller 30.

  The rotating fixing roller 30 is heated from the outside by the heater 21 at the heating nip portion Nh, and is given a necessary and sufficient amount of heat to fix the unfixed toner image T on the recording material P at the fixing nip portion Nt. .

  As described above, after the toner image T is formed in the image forming portion, the recording material P is sent to the fixing device 7 and introduced into the fixing nip portion Nt formed by the fixing roller 30 and the pressure roller 63. It is nipped and conveyed. In the process in which the recording material P is nipped and conveyed through the fixing nip portion Nt, the recording material P is heated by the fixing roller 30 and receives the nip portion pressure so that the unfixed toner image T is thermally pressed as a permanently fixed image on the recording material P surface. It is fixed.

  Next, it describes regarding the measuring method of each physical property which concerns on this invention.

(1) Element amount by EPMA (electron beam microanalyzer) on the surface of the fixing roller In the present invention, Al and / or Zn with respect to the total element amount detected when the surface of the fixing roller is measured by an electron beam microanalyzer (EPMA). The ratio of elements is specified. At this time, the Al element and the Zn element are derived from the heat conductive filler. EPMA measures elements existing to a depth of several μm from the surface, and the ratio of Al and Zn to the total amount of elements corresponds to the amount of thermally conductive filler existing at a depth of several μm from the surface. Therefore, when the abundance ratio of Al or Zn is high, it indicates that more heat conductive filler exists in the surface portion.

<Measurement conditions>
Apparatus: Electron beam microanalyzer EPMA-1610 (manufactured by Shimadzu Corporation)
Acceleration voltage: 15 kV
Irradiation current: 20 nA
Measurement time: 500msec
Beam diameter: 10 μm

(2) Thermal conductivity measurement of heat conductive filler, heat storage layer, heat insulation elastic layer and heat capacity per unit area of heat storage layer ○ Measurement of heat capacity per unit area of heat storage layer In the present invention, the heat capacity per unit area of the heat storage layer is It prescribes. Here, the surface area of the heat storage layer refers to the area of the surface of the heat storage layer that appears when all the release layers are peeled off. Therefore, the “surface area of the test piece” also represents only the area of the surface that appears when peeling as described above.

  The heat capacity per unit area of the heat storage layer is obtained by the following equation.

Heat capacity per unit area of the fixing roller = test piece volume x volume heat capacity ÷ test piece surface area or
= Volumetric heat capacity x Specific heat capacity x Heat storage layer 33 thickness Formula (Z)

  Therefore, in order to calculate the heat capacity per unit area of the heat storage layer, it is necessary to first measure the specific heat capacity and the volume heat capacity. Specific heat capacity and volumetric heat capacity were determined as follows.

  First, a test piece having a length of 5 mm and a width of 5 mm is cut out from the heat storage layer 33 of the fixing roller 30, and the test piece is measured with a dry automatic densimeter (model number AccuPyc1330, Shimadzu Corporation) to obtain a mass density.

  Next, the test piece is measured with a differential scanning calorimeter (model number DSC8240, manufactured by Rigaku Corporation) to determine the specific heat capacity.

Since the volumetric heat capacity is obtained from the following equation, it is calculated from the value obtained above.
Volumetric heat capacity = mass density x specific heat capacity

  The heat capacity per unit area of the heat storage layer was calculated by substituting the specific heat capacity and the volume heat capacity thus obtained into the formula (Z).

○ Measurement of thermal conductivity of thermal conductive filler / heat storage layer / insulating elastic layer Thermal conductivity is measured by a Fourier transform type thermal thermal diffusivity measuring device (model number FTC-1, manufactured by ULVAC-RIKO Co., Ltd.). . When measuring a heat storage layer or a heat insulating elastic layer, measurement in the thickness direction is performed. And from the following formula | equation, the heat conductivity of the heat conductive filler and the heat conductivity of the thickness direction of a thermal storage layer or a heat insulation elastic layer are calculated | required.
Thermal conductivity = thermal diffusivity x mass density x specific heat capacity

(3) Rz measuring method on the surface of the image heating member Measurement was performed at a measuring distance of 4 mm with Surfcoder SE-3300 (manufactured by Kosaka Laboratory). The measurement locations were both end portions 30 to 40 mm from the rubber end of the image heating member, and the center portion 110 to 120 mm from the rubber end. Measurements were made in the axial direction and the circumferential direction at each location, and the average value of the six measured values was defined as Rz.

(4) Toner softening temperature Tn [° C.] and outflow start temperature Tr [° C.] and the flanger positions Pn [mm] and Pr [mm] at that time
The softening temperature Tn and the outflow start temperature Tr of the toner of the present invention were measured with a flow tester CFT-500D (manufactured by Shimadzu Corporation). About 1.5 g of a 60-mesh pass product is weighed, and this is pressed using a molding machine under a load of 10 MPa for 1 minute.

  A load of 5 kgf was applied to this sample, and the plunger drop amount of the flow tester was measured by a temperature rising method at a temperature rising temperature of 4.0 ° C./min, a die diameter of 1.0 mm, and a die length of 1.0 mm. The softening temperature Tn [° C.], the outflow start temperature Tr [° C.], and the plunger drop amount are measured in mm, and the plunger positions Pn [mm] and Pr [mm] are obtained.

(5) Average Circularity The average circularity and mode circularity of the toner are measured using a flow type particle image measuring device “FPIA-2100 type” (manufactured by Sysmex Corporation), and calculated using the following equations.
First, the circularity is calculated from the following equation.
Circularity = (perimeter of a circle having the same area as the particle projection area) / (perimeter of the particle projection image)

  Here, the “particle projected area” is the area of the binarized particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the particle image. . The measurement uses the perimeter of the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm).

  In the present invention, the degree of circularity is an index indicating the degree of unevenness of particles, and is 1.00 when the particles are perfectly spherical. The more complicated the surface shape, the smaller the degree of circularity.

  The average circularity C, which means the average value of the circularity frequency distribution, is calculated from the following formula (1), where ci is the circularity at the dividing point i of the particle size distribution and m is the number of measured particles.

  A specific measurement method is as follows. First, about 10 ml of ion-exchanged water from which impure solids and the like are previously removed is put in a glass container. As a dispersant, “Contaminone N” (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH 7 precision measuring instrument cleaning, made of organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.1 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. As an ultrasonic disperser, two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dispensing System Tetora 150 type” with an electrical output of 120 W (manufactured by Nikkei Bios) Is used. A predetermined amount of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of the contamination N is added to the water tank. In that case, it cools suitably so that the temperature of the said dispersion liquid may not become 40 degreeC or more. Further, in order to suppress variation in circularity, the installation environment of the apparatus is controlled to 23 ° C. ± 0.5 ° C. so that the in-machine temperature of the flow type particle image analyzer FPIA-2100 is 26 ° C. or higher and 27 ° C. or lower. In addition, automatic focus adjustment is performed using standard latex particles of 2 μm at regular intervals, preferably every 2 hours (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific) is diluted with ion-exchanged water. Do.

The flow type particle image measuring apparatus was used for measuring the circularity of the toner particles, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and the concentration of the dispersion is readjusted and measured so that the toner particle concentration at the time of measurement is about 5000 particles / μl. After the measurement, the average circularity of the toner in the range of the circle equivalent diameter of 2.00 μm or more and less than 40.02 is obtained using this data. The equivalent circle diameter is a value calculated as follows.
Equivalent circle diameter = (particle projected area / π) 1/2 × 2

  The measuring device used in the present invention, “FPIA-2100”, has a thinner sheath flow (7 μm → 4 μm) compared to “FPIA-1000” which has been used for observing the shape of conventional toner. ) And the magnification of the processed particle image. In addition, the processing resolution of the captured image is improved (256 × 256 → 512 × 512), and the accuracy of toner shape measurement is improved.

(6) Toner weight average particle diameter (D4), number average particle diameter (D1)
The weight average particle diameter (D4) and number average particle diameter (D1) of the toner are calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, dedicated software was set up as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and the Kd value is “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(A) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(B) About 30 ml of the electrolytic solution is put into a 100 ml flat bottom beaker made of glass. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(C) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electrical output of 120 W is prepared. A predetermined amount of ion-exchanged water is placed in a water tank of an ultrasonic disperser, and about 2 ml of the contamination N is added to the water tank.
(D) The beaker of (B) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(E) In a state where the electrolytic aqueous solution in the beaker of (D) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(F) To the round bottom beaker (A) installed in the sample stand, the electrolyte solution (E) in which the toner is dispersed is dropped using a pipette, and the measured concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.
(G) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) and the number average particle diameter (D1) are calculated. When the graph / volume% is set in the dedicated software, the “average diameter” on the “Analysis / volume statistics (arithmetic average)” screen is the weight average particle diameter (D4), and the graph / number% in the dedicated software. The “average diameter” on the “analysis / number statistics (arithmetic mean)” screen is the number average particle diameter (D1).

(7) Melting point [° C.] of compatible release agent and incompatible release agent
The mold release agent, the melting point of the crystalline polyester, the mold release agent, and the endothermic peak top of the crystalline polyester are measured according to ASTM D 3417-99. The glass transition temperature (Tg) of the toner and the amorphous polyester is measured according to ASTM D 3418-99. For example, DSC-7 manufactured by Perkin Elmer, DSC2920 manufactured by TA Instruments, and TA Instruments manufactured by TA Instruments. Q1000 can be used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. An aluminum pan is used as a measurement sample, and an empty pan is set for control and measured.
In the toner of the present invention, a modulated mode was used, and measurement was performed under the following conditions to determine melting points of a compatible release agent and an incompatible release agent.

(Modulated mode measurement conditions)
• Equilibrate at 20 ° C for 1 minute.
・ Apply modulation at 1.5 ° C / min and heat up to 180 ° C at 2 ° C / min.
• Equilibrate at 180 ° C for 10 minutes.
・ Apply a modulation of 1.5 ° C / min.

(8) Acid value of crystalline polyester <Acid value>
The acid value is determined as follows. Basic operation conforms to JIS-K0070. The number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids and the like contained in 1 g of a sample is referred to as an acid value, and the test is performed by the following method.

(A) Reagent (a) As the solvent, an ethyl ether-ethyl alcohol mixed solution (1 + 1 or 2 + 1) or a benzene-ethyl alcohol mixed solution (1 + 1 or 2 + 1) was used, and these solutions were mixed with phenolphthalein as an indicator immediately before use. Neutralize with 1 mol / liter potassium hydroxide ethyl alcohol solution.
(B) Phenolphthalein solution: 1 g of phenolphthalein is dissolved in 100 ml of ethyl alcohol (95 vol%).
(C) 0.1 mol / liter potassium hydroxide-ethyl alcohol solution: Dissolve 7.0 g of potassium hydroxide in as little water as possible, add ethyl alcohol (95 vol%) to 1 liter, leave it for 2 to 3 days, and filter. . The standardization is performed according to JIS K8006 (basic matters regarding titration during the reagent content test).

  (B) Operation: 1-20 g of a sample (toner or binder resin) is weighed correctly, 100 ml of a solvent and a few drops of a phenolphthalein solution as an indicator are added thereto, and shaken sufficiently until the sample is completely dissolved. In the case of a solid sample, dissolve it by heating on a water bath. After cooling, this is titrated with a 0.1 mol / liter potassium hydroxide ethyl alcohol solution, and the end point of neutralization is taken when the indicator is slightly red for 30 seconds.

  (C) Calculation formula The acid value is calculated by the following formula.

here,
A: Acid value (mgKOH / g)
B: Amount of 0.1 mol / liter potassium hydroxide ethyl alcohol solution (ml)
f: 0.1 mol / liter of potassium hydroxide ethyl alcohol solution, factor S: sample (g)

(9) Number average molecular weight of crystalline polyester After 0.03 g of crystalline polyester was dispersed and dissolved in 10 ml of o-dichlorobenzene, it was shaken with a shaker at 135 ° C. for 24 hours, and filtered with a 0.2 μm filter. The filtrate is used as a sample.

[Analysis conditions]
Separation column: Shodex (TSK GMHHR-H HT20) × 2
Column temperature: 135 ° C
Mobile phase solvent: o-dichlorobenzene mobile phase flow rate: 1.0 ml / min.
Sample concentration: about 0.3%
Injection volume: 300 μl
Detector: Differential refractive index detector Shodex RI-71

  In calculating the molecular weight of the sample, standard polystyrene resin (TSO standard polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F- manufactured by Tosoh Corporation) was used. 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500).

(10) Solubility of release agent in styrene-acrylic resin The solubility of the release agent in styrene-acrylic resin is measured as follows.
Styrene-acrylic resin (resin obtained by polymerizing 74 parts by mass of styrene and 26 parts by mass of butyl acrylate. Glass transition temperature (Tg) = 54.0 ° C., number average molecular weight (Mn) = 200000, weight average molecular weight ( Mw) = 200000): 0.10 g
・ Release agent: 0.01g
The above is mixed in an agate mortar to obtain sample 1.

  As a measuring device, a differential scanning calorimeter “Q1000” (manufactured by TA Instruments) or “DSC2920” (manufactured by TA Instruments) can be used, and the measurement is performed according to ASTM D3418-82.

  For example, using “Q1000”, about 10 mg of sample 1 is accurately weighed, placed in an aluminum pan, and an endothermic amount is measured in the following sequence using an empty aluminum pan as a reference. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium.

Then, the endothermic peak heat quantity of the second cycle is ΔH1, and the endothermic peak heat quantity of the fourth cycle is ΔH2, and the solubility is obtained by the following equation. The endothermic peak heat quantity is the heat quantity of the maximum endothermic peak in the DSC curve in the temperature range of 30 to 120 ° C. in the temperature raising process.
Solubility = (1−ΔH2 / ΔH1) × 100

<Sequence>
1st cycle:-Hold at 30 ° C for 1 minute
・ Raise the temperature to 60 ° C at 2 ° C / min. Hold for 10 minutes after temperature rise
・ Temperature drop to 30 ° C at 10 ° C / min.
Second cycle: · Hold at 30 ° C for 1 minute
・ Raise the temperature to 120 ° C at 10 ° C / min. Hold for 10 minutes after temperature rise
・ Temperature drop to 30 ° C at 10 ° C / min.
3rd cycle: · Hold at 30 ° C for 1 minute
・ Raise the temperature to 60 ° C at 2 ° C / min. Hold for 10 minutes after temperature rise
・ Temperature drop to 30 ° C at 10 ° C / min.
4th cycle:-Hold at 30 ° C for 1 minute
・ Raise the temperature to 120 ° C at 10 ° C / min. Hold for 10 minutes after temperature rise
・ Temperature drop to 30 ° C at 10 ° C / min.

  In addition, it is preferable to use the styrene-acrylic resin described above, but when preparation is difficult, the glass transition temperature is 54.0 ° C. ± 1.0 ° C., the number average molecular weight is 20000 ± 2000, and the weight average molecular weight is 200,000 ± 20000. The styrene-acrylic resin may be used for measurement. If it is in said range, a substantially similar value will be obtained as solubility.

(11) Solubility of release agent in styrene monomer 10 g of release agent is added to 100 g of styrene monomer at 40 ° C., and the dissolution amount after stirring for 3 hours is determined.

  Hereinafter, the present invention will be specifically described with reference to production examples and examples, but this does not limit the present invention in any way. In addition, the number of parts or% used in an Example shows a mass part or mass%.

<1> Manufacture of a magnetic substance In a ferrous sulfate aqueous solution, 1.0 equivalent or more and 1.1 equivalent or less caustic soda solution with respect to iron ions were mixed to prepare an aqueous solution containing ferrous hydroxide. While maintaining the pH of the aqueous solution at 10, air was blown in, and an oxidation reaction was performed at 80 ° C. or higher and 90 ° C. or lower to prepare a slurry for generating seed crystals.

Then, after adding ferrous sulfate aqueous solution so that it becomes 0.9 equivalent or more and 1.2 equivalent or less with respect to the initial alkali amount (sodium component of caustic soda) to this slurry liquid, the slurry liquid is maintained at pH 9, The oxidation reaction was advanced while blowing air to obtain a slurry liquid containing magnetic iron oxide. After filtration and washing, the water-containing slurry was once taken out. Next, this water-containing sample was re-dispersed in another aqueous medium without drying, and then the pH of the re-dispersed liquid was adjusted to about 4.3, and the silane coupling agent (n-C ₁₀ ) was thoroughly stirred. 1.9 parts by mass of H ₂₁ Si (OCH ₃ ) ₃ ) with respect to 100 parts by mass of magnetic iron oxide was added for hydrolysis. At that time, the pH of the dispersion was set to about 10, a condensation reaction was performed, and a coupling treatment was performed. The produced hydrophobic magnetic powder was washed, filtered and dried by a conventional method, and the resulting particles were sufficiently crushed to obtain a spherical magnetic material 1 having an average particle size of 0.18 μm.

<2> Production of crystalline polyester (Production of crystalline polyester 1)
In a reactor equipped with a stirrer, a thermometer, and an outflow cooler, 230 parts by mass of 1,4-decanedicarboxylic acid, 68 parts by mass of ethylene glycol, 0.40 parts by mass of tetrabutyl titanate, and 13 parts by mass of benzoic acid were added. The esterification reaction was carried out at 190 ° C. for 4 hours. Thereafter, the system was gradually depressurized while being heated to 220 ° C., and a polycondensation reaction was carried out at 150 Pa for 6 hours to obtain a crystalline polyester 1 having a number average molecular weight of 6000 and a melting point of 83 ° C. Table 1 shows the physical properties of the obtained crystalline polyester 1.

(Production of crystalline polyester 2)
In the production of the crystalline polyester 1, the number average molecular weight is 6000, the melting point is 83 as in the production of the crystalline polyester 1 except that benzoic acid is changed to 6.5 parts by mass and 8 parts by mass of trimellitic acid is added. Crystalline polyester 2 at 0 ° C. was obtained. The physical properties of the obtained crystalline polyester 2 are shown in Table 1.

(Production of crystalline polyester 3)
In a reaction apparatus equipped with a stirrer, a thermometer, and an outflow cooler, 146 parts by mass of adipic acid (1.0 mol part), 117 parts by mass of diethylene glycol (1.1 mol part), 0.40 part by mass of tetrabutyl titanate, 13 parts by mass of benzoic acid was added, and a crystalline polyester 3 having a number average molecular weight of 6000 and a melting point of 59 ° C. was obtained by the same production method as that for producing the crystalline polyester 1. The physical properties of the obtained crystalline polyester 3 are shown in Table 1.

(Production of crystalline polyester 4)
In the production of the crystalline polyester 1, the number average molecular weight is 1900, the melting point is 83 as in the production of the crystalline polyester 1 except that the tetrabutyl titanate is changed to 0.65 parts by mass and the time for the polycondensation reaction is shortened. Crystalline polyester 4 at 0 ° C. was obtained. Table 1 shows the physical properties of the obtained crystalline polyester 4.

(Production of crystalline polyester 5)
In the production of the crystalline polyester 1, the number average molecular weight was 7200, the melting point was 83, in the same manner as the production of the crystalline polyester 1, except that tetrabutyl titanate was changed to 0.37 parts by mass and the polycondensation reaction time was increased. Crystalline polyester 5 at 0 ° C. was obtained. Table 1 shows the physical properties of the obtained crystalline polyester 5.

(Manufacture of coating solution for heat storage layer)
As a silicone rubber raw material composition, 70.0 parts by mass of addition-type silicone rubber (manufactured by Toray Dow Corning Silicone Co., Ltd. (trade name: DY35-561A / B)), alumina as a filler (manufactured by Showa Denko KK) 30.0 parts by mass of product name: alumina beads CB-A50S)). This was diluted with methyl ethyl ketone so as to have a solid content concentration of 10% to obtain a heat storage layer coating solution 1. The liquid viscosity was 3.0 × 10 ⁻² Pa · s. Moreover, the filler seed | species and compounding ratio were adjusted like Table 2, and the coating liquids 2 thru | or 6 for thermal storage layers, and the coating liquid for a comparison were obtained. “Alumina” in the table is Showa Denko Co., Ltd. alumina (trade name: Alumina Beads CB-A50S), “Zinc Oxide” is Sakai Chemical Industry Co., Ltd. zinc oxide (trade name: LPZINC-11), “Zirconia” indicates zirconia (trade name: AZI) manufactured by Aszac Co., Ltd.

(Method for manufacturing fixing roller 1)
Manufacture of elastic layer Addition-curable liquid silicone rubber material KE1218A liquid (main agent) / B liquid (curing agent) manufactured by Shin-Etsu Chemical Co., Ltd. 50 parts by mass, microballoon F80S manufactured by Matsumoto Yushi Seiyaku Co., Ltd. 3 parts by weight and softening temperature: 160 ° C. to 170 ° C.) and 1 part by weight of polyethylene glycol were added, and stirring was continued for 15 minutes to obtain a silicone rubber.

  The silicone rubber obtained above was cast on a SUM metal core having an outer diameter of 8 mm, subjected to primary vulcanization at 150 ° C. for 1 hour, and then removed from the mold and taken out. Next, after secondary vulcanization at 200 ° C. for 4 hours, heat treatment is further performed at 230 ° C. for 4 hours to form a fixing roller precursor having a low thermal conductive elastic layer having a thickness of 2.0 mm. did. This low thermal conductive elastic layer was balloon rubber and had a thermal conductivity of 0.12 W / mK.

Production of heat storage layer Next, the heat storage layer coating liquid 1 was applied to the fixing roller precursor using a ring coating apparatus. Application was performed under the conditions of a moving speed of the ring-shaped application means of 15 mm / s and a material discharge amount of 2100 mm3 / sec until the thickness reached 150 μm. Then, it is heated for 60 minutes in a 300 ° C hot air circulating heating furnace, and then the surface is polished with polishing paper (polishing machine: Super finisher made by Matsuda Seiki, polishing paper: 3M Imperial wrapping film 15 mic silicon carbide abrasive grain type) The heat storage layer was obtained. Table 3 shows the obtained physical properties.

  The “surface presence ratio” in the table indicates the ratio of aluminum and / or zinc to the total amount of elements obtained when the fixing roller is measured by EPMA. Here, aluminum and zinc elements are derived from the heat conductive filler.

(Method for manufacturing fixing roller 2)
In the method of manufacturing the fixing roller 1, the silicone rubber used for the elastic layer is changed to an addition-type silicone rubber (manufactured by Toray Dow Corning Silicone Co., Ltd. (trade name: DY35-561A / B)), and polishing is performed (polishing machine: Matsuda Seiki). Superfinisher made of abrasive paper: 3M Imperial wrapping film 5 mic silicon carbide abrasive grain type) and manufactured in the same manner as the fixing roller 1 except that the surface of the fixing roller was polished until the Rz became 4.0 μm. 2 was obtained. The thermal conductivity of the elastic layer was 0.20 W / mK. The outline of the produced roller is as shown in Table 3.

(Method for manufacturing fixing roller 3)
In the manufacturing method of the fixing roller 2, the polishing is changed to (polishing machine: Super finisher made by Matsuda Seiki, polishing paper: 3M imperial wrapping film 30 mic silicon carbide abrasive grain type), and the Rz on the surface of the fixing roller becomes 16.0 μm. A fixing roller 3 was obtained in the same manner as the fixing roller 2 except that it was polished. The outline of the produced roller is as shown in Table 3.

(Method for manufacturing fixing roller 4)
In the manufacturing method of the fixing roller 2, the polishing is changed to (polishing machine: Super finisher made by Matsuda Seiki, polishing paper: 3M imperial wrapping film 5 mic silicon carbide abrasive grain type), and until the Rz of the fixing roller surface becomes 1.4 μm A fixing roller 4 was obtained in the same manner as the fixing roller 2 except that it was polished. The outline of the produced roller is as shown in Table 3.

(Method for Manufacturing Fixing Roller 5)
In the manufacturing method of the fixing roller 2, the polishing is changed to (polishing machine: Super finisher made by Matsuda Seiki, polishing paper: 3M imperial wrapping film 30 mic silicon carbide abrasive grain type), and until the Rz of the fixing roller surface becomes 21.0 μm A fixing roller 5 was obtained in the same manner as the fixing roller 2 except that it was polished. The outline of the produced roller is as shown in Table 3.

(Method for Manufacturing Fixing Roller 6)
The elastic layer was manufactured in the same manner as the fixing roller 1.

Production of heat storage layer Next, the heat storage layer coating solution 8 was applied to the fixing roller precursor using a ring coating apparatus. The application was performed under conditions of a moving speed of the ring-shaped application means of 15 mm / s and a material discharge amount of 3000 mm ³ / sec. Then, it is heated for 60 minutes in a 300 ° C hot air circulating heating furnace, and then the surface is polished with polishing paper (polishing machine: Super Finisher made by Matsuda Seiki, polishing paper: 3M Imperial Lapping Film 15 mic silicon carbide abrasive grain type) The fixing roller precursor 2 having a heat storage layer thickness of 495 μm was obtained. The heat storage layer coating liquid 9 was applied to the fixing roller precursor 2 using a ring coating apparatus. Application was performed under the conditions of a moving speed of the ring-shaped application means of 25 mm / s and a material discharge amount of 1500 mm ³ / sec. Then, the surface is polished with polishing paper (polishing machine: Super finisher made by Matsuda Seiki, polishing paper: 3M imperial wrapping film 15 mic silicon carbide abrasive grain type), and the thickness of the heat storage layer applied repeatedly is 10 μm ( Polishing was performed until the total thickness of the heat storage layer reached 505 μm, and the fixing roller 6 was obtained. Table 3 shows the obtained physical properties.

(Method for manufacturing fixing roller 7)
The elastic layer was manufactured in the same manner as the fixing roller 1.

Production of heat storage layer Next, the heat storage layer coating solution 10 was applied to the fixing roller precursor using a ring coating apparatus. Application was performed under the conditions of a moving speed of the ring-shaped application means of 35 mm / s and a material discharge amount of 1500 mm ³ / sec. Then, it is heated for 60 minutes in a 300 ° C hot air circulating heating furnace, and then the surface is polished with polishing paper (polishing machine: Super Finisher made by Matsuda Seiki, polishing paper: 3M Imperial Lapping Film 15 mic silicon carbide abrasive grain type) The fixing roller precursor 2 having a heat storage layer thickness of 38 μm was obtained. Thereafter, in the same manner as in the production of the fixing roller 6, the coating solution 9 for the heat storage layer is applied using a ring coating apparatus, and the thickness of the heat storage layer applied repeatedly is 10 μm (the total heat storage layer thickness is The fixing roller 7 was obtained by polishing until 48 μm). Table 3 shows the obtained physical properties.

(Method for manufacturing fixing roller 8)
The elastic layer was manufactured in the same manner as the fixing roller 1.

Production of heat storage layer Next, the heat storage layer coating solution 1 was applied and polished under the same conditions as in the production of the fixing roller 1 to obtain a fixing roller precursor 2 having a heat storage layer thickness of 150 μm. Thereafter, in the same manner as the manufacture of the fixing roller 6, the heat storage layer coating liquid 2 is applied using a ring coating apparatus, and the thickness of the heat storage layer applied in layers is 10 μm (the total heat storage layer thickness is Polishing was performed until the thickness became 160 μm, whereby the fixing roller 8 was obtained. Table 3 shows the obtained physical properties.

(Method for manufacturing fixing roller 9)
A fixing roller 9 was obtained in the same manner as the fixing roller 8 except that the heat storage layer coating solution 3 was used instead of the heat storage layer coating solution 2 in the manufacture of the fixing roller 8. Table 3 shows the obtained physical properties.

(Method for Manufacturing Fixing Roller 10)
In the manufacturing method of the fixing roller 1, the heat storage layer coating solution 4 is used instead of the heat storage layer coating solution 1, and the dipping coating device is used instead of the ring coating device. Thus, the fixing roller 10 was obtained. Table 3 shows the obtained physical properties.

(Method for Manufacturing Fixing Roller 11)
A fixing roller 11 was obtained in the same manner as the fixing roller 1 except that the heat storage layer coating solution 5 was used in place of the heat storage layer coating solution 4 in the method of manufacturing the fixing roller 10. Table 3 shows the obtained physical properties.

(Method for Manufacturing Fixing Roller 12)
A fixing roller 12 was obtained in the same manner as the method for manufacturing the fixing roller 6 except that the heat storage layer coating solution 6 was used instead of the heat storage layer coating solution 8 in the method of manufacturing the fixing roller 6. Table 3 shows the obtained physical properties.

(Method for Manufacturing Fixing Roller 13)
A fixing roller 13 was obtained in the same manner as the method for manufacturing the fixing roller 6 except that the heat storage layer coating solution 7 was used instead of the heat storage layer coating solution 10 in the method of manufacturing the fixing roller 7. Table 3 shows the obtained physical properties.

(Method for Manufacturing Fixing Roller 14)
A fixing roller 14 was obtained in the same manner as the method for manufacturing the fixing roller 10 except that the heat storage layer coating solution 11 was used instead of the heat storage layer coating solution 4 in the method of manufacturing the fixing roller 10. Table 3 shows the obtained physical properties.

  For the fixing roller 14 only, “surface element ratio” in the table indicates the abundance ratio of zirconium with respect to the total element amount detected by EPAM measurement.

<3> Manufacture of magnetic toner (Manufacture of magnetic toner 1)
After adding 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution to 720 parts by mass of ion-exchanged water and heating to 60 ° C., 67.7 parts by mass of 1.0 M CaCl ₂ aqueous solution was added to add a dispersion stabilizer. An aqueous medium containing was obtained.

Styrene 79.0 parts by mass n-butyl acrylate 21.0 parts by mass Divinylbenzene 0.48 parts by mass Negative charge control agent (monoazo dye-based Fe compound) 1.5 parts by mass Crystalline polyester 1 10 parts by mass Surface-treated magnetic substance 1 85.0 parts by mass The above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Chemical Co., Ltd.). This monomer composition was heated to 60 ° C., and 15 parts by mass of paraffin wax (melting point: 78 ° C.) was added and dissolved therein. The polymerization initiator 2,2′-azobis- (2,4-dimethylvalero) was added thereto. Nitrile) 7 parts by mass was dissolved.

The polymerizable monomer composition was charged into the aqueous medium, and the mixture was granulated by stirring at 15,000 rpm for 10 minutes with Claremix (manufactured by M Technique) in an N ₂ atmosphere at 60 ° C. The mixture was then reacted at 70 ° C. for 5 hours while stirring with a paddle stirring blade, and then stirred for 2 hours. After completion of the reaction, the suspension was cooled, acid washed with hydrochloric acid, filtered, washed with water, and dried to obtain toner particles 1.

The toner particles 1 were treated with 100 parts by mass and a fine powder with a number average primary particle size of 9 nm treated with hexamethyldisilazane and then with silicone oil. The hydrophobic silica fine particles with a BET value after treatment of 200 m ² / g 1.2 parts by mass of the powder was mixed with a Henschel mixer (Mitsui Miike Chemical Co., Ltd.) to obtain a magnetic toner 1 having a weight average particle diameter of 6.5 μm. Table 4 shows the physical properties of the magnetic toner 1 obtained.

(Manufacture of magnetic toner 2)
Magnetic toner 2 was obtained in the same manner as magnetic toner 1 except that crystalline polyester 3 was used instead of crystalline polyester 1 in the production of magnetic toner 1. Table 4 shows the physical properties of the magnetic toner 2.

(Manufacture of magnetic toner 3)
Manufacture of magnetic toner 1 except that the number of parts of crystalline polyester 1 is changed from 10 parts by weight to 1 part by weight and the number of parts of paraffin wax (melting point: 78 ° C.) is changed from 15 parts by weight to 1 part by weight. Magnetic toner 3 was obtained in the same manner as above. Table 4 shows the physical properties of the magnetic toner 3.

(Manufacture of magnetic toner 4)
Manufacture of magnetic toner 1 except that the number of parts of crystalline polyester 1 was changed from 10 parts by weight to 31 parts by weight, and the number of parts of paraffin wax (melting point 78 ° C.) was changed from 15 parts by weight to 31 parts by weight. Magnetic toner 4 was obtained in the same manner as above. Table 4 shows the physical properties of the magnetic toner 4.

(Manufacture of magnetic toner 5)
Magnetic toner 1 was produced in the same manner as magnetic toner 1 except that ester wax (melting point 63 ° C.) was used instead of paraffin wax and crystalline polyester 2 was used instead of crystalline polyester 1 in the production of magnetic toner 1. 5 was obtained. Table 4 shows the physical properties of the magnetic toner 5.

(Manufacture of magnetic toner 6)
Magnetic toner 6 was obtained in the same manner as magnetic toner 1 except that crystalline polyester 4 was used in place of crystalline polyester 1 in the production of magnetic toner 1. Table 4 shows the physical properties of the magnetic toner 6.

(Manufacture of magnetic toner 7)
Magnetic toner 7 was obtained in the same manner as magnetic toner 1 except that crystalline polyester 5 was used in place of crystalline polyester 1 in the production of magnetic toner 1. Table 4 shows the physical properties of the magnetic toner 7.

(Manufacture of magnetic toner 8)
In the production of the magnetic toner 1, the magnetic toner 8 was obtained in the same manner as in the production of the magnetic toner 1 except that no release agent was contained. Table 4 shows the physical properties of the magnetic toner 8.

(Manufacture of magnetic toner 9)
In the production of the magnetic toner 1, the magnetic toner 9 was obtained in the same manner as in the production of the magnetic toner 1 except that the crystalline polyester 1 was not used. Table 4 shows the physical properties of the magnetic toner 9.

(Manufacture of magnetic toner 10)
In the production of the magnetic toner 1, the number of parts of the crystalline polyester 1 is changed from 10 parts by weight to 35 parts by weight, and the number of parts of the paraffin wax (melting point 78 ° C.) is changed from 10 parts by weight to 35 parts by weight. Was heated to 90 ° C., stirred for 2 hours and then cooled to obtain a magnetic toner 10 in the same manner as in the production of the magnetic toner 1. Table 4 shows the physical properties of the magnetic toner 10.

(Manufacture of magnetic toner 11)
Magnetic toner 11 was obtained in the same manner as magnetic toner 1 except that 0.18 parts by mass of divinylbenzene was used in the production of magnetic toner 1. Table 4 shows the physical properties of the magnetic toner 11.

(Manufacture of magnetic toner 12)
Magnetic toner 12 was obtained in the same manner as magnetic toner 1 except that 1.03 parts by mass of divinylbenzene was used in the production of magnetic toner 1. Table 4 shows the physical properties of the magnetic toner 12.

<Example 1>
Using the magnetic toner 1 and the fixing roller 1, the fixing characteristics were evaluated using the image forming apparatus 1 shown in FIG. 4 provided with the fixing device 7 shown in FIG.

  The evaluation of the fixing characteristics is performed by passing the recording material P on which the unfixed toner image T is formed through the fixing device 7, and the experiment is performed in a state where the temperature of the heater 21, the fixing roller 30 and the entire fixing device is familiar with the ambient temperature. (Hereinafter, this condition is referred to as a cold start). The environment during the experiment was a normal temperature and humidity environment (23 ° C., 60% RH).

  As shown in FIG. 2, the surface temperature of the fixing roller 30 is the non-contact radiation thermometer 103 which is the surface temperature of the fixing roller at the intermediate position D from the heating nip portion Nh to the fixing nip portion Nt in the rotation direction of the fixing roller 30. Use to measure.

  Simultaneously with the start of rotation of the fixing roller 30 from the cold start, 500 W of electric power is applied to the ceramic heater 21 to heat the ceramic heater, thereby heating the fixing roller 30 and raising the fixing roller to a target temperature.

  The temperature of the fixing roller 30 is controlled using the radiation thermometer 103, and after reaching the desired fixing roller temperature, the power of the ceramic heater is controlled so as to maintain the target temperature.

  After a warm-up time of 20 seconds, the recording material P on which the unfixed toner image T is formed is passed.

  When changing the surface temperature of the fixing roller, it was controlled by changing the temperature control temperature of the ceramic heater.

  Table 5 shows the combinations of toners and rollers that have undergone image formation evaluation, and the evaluation results.

  As a result of fixing evaluation under the above conditions, excellent low-temperature fixing property was exhibited. Further, no wrapping of the recording material occurred.

  In addition, the commercially available laser beam printer LBP-3210 was modified to replace the fixing member of the present invention. Further, the toner in the CRG was extracted and filled with the magnetic toner 1, and a long-term durability test was conducted. Specifically, 4000 sheet passing durability tests were performed in a normal temperature and normal humidity environment (temperature 23 ° C., humidity 60%). The original used a chart with an image ratio of 8%. In a normal temperature and humidity environment, the image density and fixing roller stain were evaluated based on the following evaluation criteria. As a result, an image density having no problem was obtained at the initial stage of image evaluation and after the endurance of 4000 sheets. Further, no fouling of the fixing roller was observed after the endurance of 2000 sheets and after the endurance of 4000 sheets. The results are shown in Table 5.

  The image evaluation method and evaluation criteria of the present invention will be described below.

(1) Image Density Using an Xerox Business 4200 (75 g / m ² ), after completing the initial and 4000 printouts, a solid image portion was formed and evaluated. The image density was measured by using a “Macbeth reflection densitometer” (manufactured by Macbeth Co.), which is an image density measuring device, to measure a relative density with respect to a printout image of a white background portion having a document density of 0.00. If the image density is 1.30 or more, the image has no practical problem.

(2) Low-temperature fixability Extra 80g paper was used as the media, and the development bias was set so that the image density of the halftone image was 0.6 to 0.65. Next, the fixing device is cooled to room temperature and normal humidity or a temperature in a high temperature and high humidity environment, the heater temperature of the fixing device is set (hereinafter referred to as the fixing temperature), and the image is passed through after 8 seconds from energization. And fixed. Thereafter, the fixed image was rubbed 10 times with a Silbon paper to which a weight of 50 g / cm ² was applied, and the temperature at which the density reduction rate of the fixed image after the rub was 10% was defined as the fixing start temperature.
A: A stable fixed image can be obtained when the minimum fixable temperature is 150 ° C. or higher and 170 ° C. or lower.
B: A stable fixed image can be obtained when the minimum fixable temperature is higher than 170 ° C and lower than 190 ° C.
C: A stable fixed image can be obtained when the minimum fixable temperature is higher than 190 ° C. and lower than 200 ° C.
D: The minimum fixable temperature is higher than 200 ° C. or does not have a fixable temperature.

(3) Wound level A solid black unfixed image having a width of 60 mm was output on a BADGER BOND (60 g / m ² ) paper at a position 3 mm from the leading edge of the recording material. Thereafter, in the fixing test of (2), 100 sheets are intermittently passed for 10 seconds at a fixing temperature at which the density reduction rate of the fixed image after rubbing becomes 10%. It was evaluated with.
A: No wrapping occurs.
D: Winding occurs.

(4) Fixing Roller Stain A solid black unfixed image having a width of 60 mm was output onto BADGER BOND (60 g / m ² ) paper at a position 3 mm from the leading end of the recording material. After that, in the fixing test (2), 10 sheets are passed intermittently for 10 seconds at a fixing temperature at which the density reduction rate of the fixed image after rubbing becomes 10%. did.
A: The fixing roller is not stained and a fixed image having no problem can be obtained.
B: Fixing image with no problem is obtained although the fixing roller is slightly stained.
C: Fixing image with practically no problem can be obtained although the fixing roller is stained.
D: Many fixing roller stains are observed, and a good fixed image cannot be obtained.

<Examples 2 to 17>
Magnetic toners 2, 3, 4, 5, 6, 7, 11, 12 and fixing rollers 1, 2, 3, 4, 5, 6, 7 are used as shown in Table 4 under the same conditions as in Example 1. An image output test and durability evaluation were performed. As a result, in image evaluation under a normal temperature and normal humidity environment, a result having no practical problem was obtained even after the endurance of image printing for 4000 sheets. Table 5 shows the evaluation results in a room temperature and normal humidity environment.

<Comparative Examples 1 to 8>
The magnetic toner 1, 8, 9, 10, or 13 and the fixing roller 1, 8, 9, 10 were used as shown in Table 4, and the image output test and durability evaluation were performed under the same conditions as in Example 1. went. As a result, the low temperature fixability and fixing unevenness were both poor due to the lack of the volume expansion effect described above. The results are shown in Table 5.

It is a schematic diagram of the image heating member in the present invention. FIG. 2 is a schematic diagram of a fixing device according to the present invention. It is a schematic diagram explaining the ring coating apparatus used preferably. 1 is a schematic diagram of an example of an image forming apparatus that can be used in the present invention.

Claims (16)

A charging step of charging the electrostatic latent image carrier with charging means, an exposure step of exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and developing the electrostatic latent image with toner A developing step for forming a toner image, a transfer step for transferring the toner image to a recording material with or without an intermediate transfer member, and an image heating member capable of rotating the recording material carrying the toner image with a pressure member. In an image forming method having a fixing step of fixing by heating and pressing by passing through a nip formed by
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The toner applied to the image heating apparatus includes at least one binder resin, a magnetic material, and at least one release agent compatible with the binder resin, and at least one release agent incompatible with the binder resin. At least when the softening temperature of the magnetic toner measured by a flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the respective plunger positions are Pn [mm] and Pr [ mm], 1.1 ≦ Pn / Pr ≦ 1.5 is satisfied.   The image forming method according to claim 1, wherein Rz of the image heating member is 2.0 μm or more and 20.0 μm or less.   3. The image forming method according to claim 1, wherein the heat conductive filler is contained in an amount of 7 parts by mass to 60 parts by mass with respect to 100 parts by mass of the rubber forming the heat storage layer.   The image forming method according to claim 1, wherein a thickness of the heat storage layer is 50.0 μm or more and 500.0 μm or less.   The image forming method according to claim 1, wherein the elastic layer has a thermal conductivity of 0.15 W / mK or less.   6. The image forming method according to claim 1, wherein the image heating member is provided with means for heating from the outside.   The image forming method according to claim 1, wherein the magnetic toner contains 0.2 to 1.0 part by mass of a crosslinking agent with respect to 100 parts by mass of the binder resin. .   The image forming method according to claim 1, wherein the magnetic toner has an average circularity of 0.960 or more.   When Tm1 [° C.] is one melting point of the release agent compatible with the binder resin and Tm2 [° C.] is one melting point of the release agent incompatible with the binder resin, Tm1 is 9. The image forming method according to claim 1, wherein the image forming method is 50 ° C. or more and satisfies Tm1 ≦ Tm2 + 10.   The toner has 2 to 30 parts by mass of a release agent compatible with the binder resin and 2 to 30 parts by mass of a release agent incompatible with the binder resin with respect to 100 parts by mass of the binder resin. The image forming method according to claim 1, wherein the image forming method is contained in an amount of not more than part by mass.   The image forming method according to claim 1, wherein the incompatible release agent is a crystalline polyester.   The image forming method according to claim 11, wherein the crystalline polyester is a polycondensate of a linear dicarboxylic acid and a linear aliphatic dialcohol. 13. The image forming method according to claim 11, wherein the acid value of the crystalline polyester is 5 [mg KOH / g] or less.   The image forming method according to claim 11, wherein the crystalline polyester has a number average molecular weight of 2,000 to 7,000. A charging step of charging the electrostatic latent image carrier with charging means, an exposure step of exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and developing the electrostatic latent image with toner A developing step for forming a toner image, a transfer step for transferring the toner image to a recording material with or without an intermediate transfer member, and an image heating member capable of rotating the recording material carrying the toner image with a pressure member. In a fixing method having a fixing step of fixing under heat and pressure by passing through a nip formed by
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The toner is a magnetic toner containing at least one binder resin, a magnetic material, and one or more release agents compatible with the binder resin, and at least one release agent incompatible with the binder resin. When the softening temperature of the magnetic toner measured by the flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the plunger positions are Pn [mm] and Pr [mm], respectively. ≦ Pn / Pr ≦ 1.5 satisfying the fixing method. A charging step of charging the electrostatic latent image carrier with charging means, an exposure step of exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and developing the electrostatic latent image with toner A developing step for forming a toner image, a transfer step for transferring the toner image to a recording material with or without an intermediate transfer member, and an image heating member capable of rotating the recording material carrying the toner image with a pressure member. In a magnetic toner used for an image forming method having a fixing step of fixing by heating and pressing by passing through a nip formed by
Said image heating member having an inner elastic layer, the heat capacity per unit area of the image heating member to the outside, has a 100 J / m ² K or more 600 J / m ² K or less of the heat storage layer,
The image heating member contains a heat conductive filler having a heat conductivity of 5.0 W / mK or more,
The thermally conductive filler is Al and / or Zn compound,
4. The ratio of the aluminum element and / or zinc element derived from the heat conductive filler when the surface of the image heating member is measured by EPMA (electron beam microanalyzer) is 5. 0 mass% or more and 45.0 mass% or less,
The magnetic toner is a magnetic toner containing at least one binder resin, a magnetic material, and at least one release agent compatible with the binder resin, and at least one release agent incompatible with the binder resin. When the softening temperature of the magnetic toner measured by the flow tester is Tn [° C.] and the outflow start temperature is Tr [° C.], the respective plunger positions are Pn [mm] and Pr [mm]. 1. Magnetic toner satisfying 1 ≦ Pn / Pr ≦ 1.5.

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