JP2021063873A - Image forming method and image forming apparatus - Google Patents

Abstract

To provide an image forming method and an image forming apparatus that prevent an uncontrolled toner from scattering from a recording medium in an optical fixing system and are excellent in energy saving.SOLUTION: An image forming method of the present invention is an image forming method for optically fixing at least a toner image formed by using toner, and the toner contains a compound that undergoes solid-liquid phase transition upon absorption of light. The method has: a developing step of forming a toner image by using the toner based on image data; a step of transferring the toner image onto a recording medium; and a step of irradiating, with light, the toner image transferred onto the recording medium to fuse or soften the toner image. When an integrated quantity of light with which a position equivalent to an image area on the recording medium corresponding to the image data is irradiated is A[J/cm2], and an integrated quantity of light with which a position equivalent to an area other than the image area is irradiated is B[J/cm2], a following formula (1) is satisfied. Formula (1) A≥B.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image forming method and an image forming apparatus, and more particularly to an image forming method and an image forming apparatus which suppresses uncontrolled toner from scattering from a recording medium and is excellent in energy saving in an optical fixing system. ..

In the electrophotographic process, a fixing system using light (hereinafter referred to as an optical fixing system) has been proposed in order to shorten the warming up time, save energy, and expand the types of recording media.

As currently known optical fixing systems, many systems have been proposed in which toner is melt-fixed to a recording medium by converting light into heat (see, for example, Patent Documents 1 and 2). Patent Document 1 presents a method of irradiating only an image forming portion with light based on image data, and it is said that energy consumption can be reduced.

However, if the toner adheres to a position where there is no image data due to toner scattering or some other reason (hereinafter, the adhered toner is referred to as "uncontrolled toner"), it is fixed by the above method. Since the recording medium to which the uncontrolled toner is attached is discharged as it is, the uncontrolled toner may scatter and stain the body and clothes of the user, etc., or may be sucked by breathing and enter the human body. It becomes a problem.

On the other hand, in Patent Document 2, isolated dots in which dots are not formed at adjacent positions are affected by heat escape to a recording medium or the like, so it is necessary to increase the emitted light energy in order to obtain sufficient fixing strength. It has been reported that there is.

In order to suppress the scattering of the uncontrolled toner that has not been fixed, when the uncontrolled toner is fixed by irradiating light even at a position where there is no image data, the uncontrolled toner often becomes an isolated dot, as described above. Since excessive energy is required to fix the isolated dots, there is a problem that energy saving becomes difficult.

Japanese Unexamined Patent Publication No. 2010-128157 Japanese Unexamined Patent Publication No. 2013-156303

The present invention has been made in view of the above problems and situations, and the problem to be solved is an image forming method that suppresses uncontrolled toner from scattering from a recording medium in an optical fixing system and is further excellent in energy saving. And to provide an image forming apparatus.

The present inventor is an image forming method for photofixing toner in the process of examining the cause of the problem in order to solve the above problems, and is a compound that undergoes a solid-liquid phase transition when the toner absorbs light. After forming a toner image using the toner, when the toner image is irradiated with light to be melted or softened and fixed, the toner image is irradiated to a position corresponding to a position other than the image area and the image area. It has been found that by controlling the integrated light amount of light in a specific relationship, it is possible to suppress the scattering of uncontrolled toner from the recording medium and obtain an image forming method excellent in energy saving.

That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. An image forming method for photofixing at least a toner image formed by using toner.
The toner contains a compound that undergoes a solid-liquid phase transition by absorbing light.
A developing process that forms a toner image using the toner based on image data,
The step of transferring the toner image onto a recording medium and
The toner image transferred onto the recording medium is irradiated with light to melt or soften the toner image, and the toner image is melted or softened.
The integrated light amount of the light to be applied to a position corresponding to the image area on the recording medium corresponding to the image data is A [J / cm ² ], and the integrated light to be applied to a position other than the image area is integrated. An image forming method characterized in that the following equation (1) is satisfied when the amount of light is B [J / cm ^2].

Equation (1) A ≧ B

2. The image forming method according to item 1, wherein the integrated light amounts A and B satisfy the following formula (2).

Equation (2) A ≧ 2 × B

3. 3. The image forming method according to item 2, wherein the integrated light amounts A and B satisfy the following formula (3).

Equation (3) A ≧ 5 × B

4. ^{The illuminance [W / cm 2} ] differs by 0.1 [W / cm ² ] or more between the light irradiating the position corresponding to the image area and the light irradiating the position other than the image area. The image forming method according to any one of the items 1 to 3.

5. The first term is characterized in that the irradiation time (sec) differs by 0.01 (sec) or more between the light irradiating the position corresponding to the image area and the light irradiating the position other than the image area. The image forming method according to any one of items 1 to 3.

6. Items 1 to 5 characterized in that, in the step of irradiating the light to melt or soften the toner image, the irradiated light is monochromatic synchrotron radiation having a maximum emission wavelength in the range of 280 to 480 nm. The image forming method according to any one of the above items.

7. The image forming method according to any one of items 1 to 6, wherein the compound that undergoes a solid-liquid phase transition is an azobenzene derivative or an azomethin derivative.

8. The image forming method according to any one of items 1 to 7, further comprising a step of further pressurizing the softened toner image.

9. The image forming method according to item 8, further comprising a step of further heating the toner image in the pressurizing step.

10. The image forming method according to item 9, further comprising a step of cooling the toner image after the heating step.

11. An image forming apparatus for light-fixing at least a toner image formed by using toner.
The toner is a toner containing a compound that undergoes a solid-liquid phase transition by absorbing light.
A developing unit that forms a toner image using the toner based on image data,
A transfer unit that transfers the toner image onto a recording medium,
An irradiation unit that irradiates the toner image transferred onto the recording medium with light, and an irradiation unit.
^{Let A [J / cm 2} ] be the integrated amount of light emitted to a position corresponding to the image area on the recording medium corresponding to the image data, and the integrated amount of light to be applied to a position other than the image area. When B [J / cm ² ] is set to, a light irradiation control unit that controls the light to be irradiated so as to satisfy the following equation (1), and a light irradiation control unit.
An image forming apparatus characterized by having.

Equation (1) A ≧ B

According to the above means of the present invention, it is possible to provide an image forming method and an image forming apparatus which suppresses uncontrolled toner from scattering from a recording medium and is excellent in energy saving in an optical fixing system.

Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.

In the optical fixing system, the image forming unit (referred to as “image area” in the present invention) is selectively irradiated with light on the recording medium based on the position information of the image data, so that the energy is efficiently used and the toner is used. The image can be fixed. On the other hand, in order to fix the uncontrolled toner unintentionally adhered to the recording medium other than the image area, it is necessary to irradiate the light to the area other than the image area, and the generation of scattered toner can be suppressed.

Here, most of the uncontrolled toner is isolated dots such as fog toner or scattered toner, and the amount of toner adhered per area is small. For toner containing a compound that undergoes a solid-liquid phase transition by absorbing light, when the amount of toner adhered is small, such as isolated dots, the toner is softened and melt-fixed by irradiating a small amount of integrated light according to the amount of adhered toner. can do.

Therefore, by irradiating the uncontrolled toner other than the image area with a small amount of light equal to or less than the integrated light amount for the image area, the uncontrolled toner can be fixed, so that the generation of scattered toner can be suppressed. Moreover, it is presumed that energy consumption can be suppressed.

Schematic configuration diagram showing an example of the configuration of an image forming apparatus applicable to an image forming method. Schematic configuration diagram showing an example of the configuration of the irradiation unit constituting the image forming apparatus

The image forming method of the present invention is an image forming method in which at least a toner image formed by using toner is photofixed, and the toner contains a compound that undergoes a solid-liquid phase transition by absorbing light, and an image is formed. The development step of forming a toner image using the toner based on the data, the step of transferring the toner image onto a recording medium, and the step of irradiating the toner image transferred onto the recording medium with light are described. ^{A [J / cm 2} ] is defined as the integrated amount of light that has a step of melting or softening the toner image and irradiates a position corresponding to an image area on a recording medium corresponding to the image data. When the integrated light amount of the light irradiating to a position other than the image area is B [J / cm ² ], the above formula (1) is satisfied. This feature is a technical feature common to or corresponding to the following embodiments.

In an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, the integrated light amounts A and B satisfy the above formula (2) and further the above formula (3), so that the uncontrolled toner scatters from the recording medium. This is preferable from the viewpoint of suppressing the amount of energy saving and achieving energy saving.

^{In order to satisfy the above formulas (1) to (3), the illuminance [W / cm 2} ] is 0 in the light irradiating the position corresponding to the image area and the light irradiating the position other than the image area. It is preferable to control the irradiation time (sec) to be different by 1 [W / cm ^{2] or more, or 0.01 (sec) or more.}

Further, in the step of irradiating the light to melt or soften the toner image, it is preferable that the irradiated light is monochromatic synchrotron radiation having a maximum emission wavelength in the range of 280 to 480 nm from the viewpoint of energy saving. ..

Further, it is preferable that the compound that undergoes the solid-liquid phase transition according to the present invention is an azobenzene derivative or an azomethine derivative because the reaction rate of melting or softening to the irradiation of light is high and energy saving is achieved.

In the image forming method of the present invention, it is preferable to have a step of further pressurizing the softened toner image, and further having a step of heating the toner image and a step of cooling the uncontrolled toner on the recording medium. It is preferable from the viewpoint of fixing.

The image forming apparatus of the present invention is an image forming apparatus that photofixes at least a toner image formed by using toner, and is a toner containing a compound that undergoes a solid-liquid phase transition when the toner absorbs light. Light is applied to a developing unit that forms a toner image using the toner based on data, a transfer unit that transfers the toner image onto a recording medium, and the toner image transferred onto the recording medium. ^{Let A [J / cm 2} ] be the integrated amount of light to be applied to the irradiation unit and the position corresponding to the image area on the recording medium corresponding to the image data, and irradiate to a position other than the image area. When the integrated light amount of light is B [J / cm ² ], it is characterized by having a light irradiation control unit that controls the light to be irradiated so as to satisfy the above formula (1).

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

[1] Outline of the image forming method of the present invention The image forming method of the present invention is an image forming method in which at least a toner image formed by using toner is photofixed, and the toner absorbs light. A development step of forming a toner image using the toner based on image data containing a compound that undergoes a solid-liquid phase transition, a step of transferring the toner image onto a recording medium, and the step of transferring the toner image onto the recording medium. A step of irradiating a toner image with light to melt or soften the toner image, and integrating light to irradiate a position corresponding to an image area on a recording medium corresponding to the image data. When the amount of light is A [J / cm ² ] and the total amount of light emitted to a position other than the image area is B [J / cm ² ], the following equation (1) is satisfied. ..

Equation (1) A ≧ B

The image forming method of the present invention employs a photofixing system using a toner containing a compound (also referred to as a photophase transition material) that undergoes a solid-liquid phase transition by absorbing light.

The optical fixing system has a development step of forming a toner image using the toner based on at least image data, a step of transferring the toner image onto a recording medium, and a step of transferring the toner image onto the recording medium. The toner image is irradiated with light to melt or soften the toner image.

In the optical fixing system, it is possible to selectively irradiate an image area on a recording medium based on the position information of image data, and similarly, selectively irradiate a position other than the image area. Therefore, it is possible to irradiate the uncontrolled toner other than the image area with light with an integrated light amount equal to or less than the light irradiation amount to the image area, and the uncontrolled toner. Can be efficiently fixed. Therefore, since the irradiation amount of light for fixing the uncontrolled toner can be controlled to the minimum, the amount of scattered toner can be suppressed and the energy consumption can be suppressed at the same time.

The relationship between the integrated light amount A and the integrated light amount B preferably satisfies the formula (2) A ≧ 2 × B, and satisfying the formula (3) A ≧ 5 × B is more preferable from the viewpoint of reducing energy consumption. preferable. The integrated light amount can be controlled by appropriately selecting the type and amount of the compound that undergoes a solid-liquid phase transition by absorbing light, the emission wavelength of light, and the like.

In the present invention, "uncontrolled toner" is a general term for toner to which toner has adhered to a position where there is no image data due to toner scattering or some other cause, and is "fog toner" or "scattered toner". May be said. Further, the "isolated dot" refers to a point image at a position where dots by toner are not formed at adjacent positions, and whether or not it is "isolated" can be determined by microscopic observation.

In the step of irradiating the light according to the present invention to melt or soften the toner image, the irradiated light is preferably monochromatic synchrotron radiation having a maximum emission wavelength in the range of 280 to 480 nm, and the maximum emission wavelength is More preferably, it is monochromatic synchrotron radiation in the range of 330 to 400 nm. If it is within the above range, the regular structure is liable to be broken by absorbing light, and the photomeltability and fixability are improved.

The light source of the emitted light is a light source that emits monochromatic synchrotron radiation in the range of 280 to 480 nm, and can be defined as a single frequency or a single wavelength. It refers to a light source that emits light with a very small change width from a specific frequency or a very small change width from a specific wavelength. ) And so on. In the present invention, monochromatic synchrotron radiation is defined as synchrotron radiation that emits light in a wavelength region of the maximum emission wavelength (nm) ± 20 (nm), which indicates the maximum intensity of emission.

Integrated light quantity A of the light to be irradiated on the image zone, which can be sufficiently melted or softened toner image, preferably in the range of 0.01~100J / cm ^2, more preferably 0.05~50J / cm ^{2 It is in the range of 0.1 to 30 J / cm 2} , and more preferably in the range of 0.1 to 30 J / cm 2.

In the image forming apparatus 100 described later, the fixing unit 9 includes at least an irradiation unit 40. As an example of the device constituting the irradiation unit 40, as described above, an LED or LD which is a monochromatic radiation light source can be mentioned. Monochromatic synchrotron radiation is emitted from the irradiation unit 40.

Integrated light quantity B of the light to be irradiated on the non-image area is softened uncontrolled toner, which can be bonded, preferably in the range of 0.01~100J / cm ^2, more preferably 0.01~50J / cm ^{2 It is in the range of 0.01 to 30 J / cm 2} , more preferably in the range of 0.01 to 30 J / cm 2.

The light irradiation step may include a first light irradiation step of irradiating the image area with light and a second light irradiation step of irradiating light other than the image area, or an image in one light irradiation step. Light irradiation may be performed by controlling the integrated light amount in the area and the area other than the image area. From the viewpoint of simplification and miniaturization of the device, the method of performing the light irradiation step is preferable.

^{The illuminance [W / cm 2} ] differs by 0.1 [W / cm ² ] or more, or the irradiation time, between the light irradiating the position corresponding to the image area and the light irradiating the position other than the image area. It is preferable to control so that (sec) differs by 0.01 (sec) or more.
The difference in illuminance is preferably in the range of 0.1 to 5.0 [W / cm ² ], and the difference in irradiation time (sec) is in the range of 0.01 to 0.5 (sec). Is preferable.

The method of controlling the integrated light amount is preferably a method of changing the illuminance of light irradiation. In the case of the method of controlling the illuminance, it is easy to control the integrated light amount with the same irradiation time outside the image area and the image area, and the device configuration can be simplified. The illuminance can be controlled by the current value.

As a method of controlling the integrated light amount, a method of changing the irradiation time can be used, but in that case, it is preferable to control the irradiation time by turning on / off the light source.

From the viewpoint of preventing scattered toner from the toner image melted or softened by light irradiation, it is preferable that the image forming method further includes a step of pressurizing the toner image. The force for pressurizing the toner image is not particularly limited, but the toner image transferred onto the recording medium is preferably added in the range of 0.01 to 1.0 MPa, more preferably in the range of 0.1 to 0.5 MPa. Press. By pressurizing in the above range, the adhesion between the uncontrolled toner and the recording medium can be improved, and the amount of scattered toner can be further reduced.

Further, it is more preferable to heat in the step of pressurizing. At the same time that the fixing strength of the toner image in the image forming portion can be increased, the adhesion and adhesiveness of the uncontrolled toner to the recording medium can be improved, and the amount of scattered toner can be further reduced.

Further, it is more preferable to have a step of cooling after heating in the step of pressurizing. By solidifying the toner quickly, it is possible to suppress adhesion to members and the like.

The toner according to the present invention is preferably a toner for developing an electrostatic charge image, and contains at least a photophase transition material. Specifically, it is preferable to contain toner matrix particles composed of the photophase transition material, a binder resin, and a colorant, and an external additive. In addition to the binder resin and the colorant, the toner matrix particles may contain various internal additives such as a mold release agent, a charge control agent, and a surfactant, if necessary.

In the present invention, the "toner" refers to an aggregate of "toner particles", and the toner particles refer to the above-mentioned toner matrix particles to which an external additive is added. Further, in the following description, when it is not necessary to particularly distinguish between the toner base particles and the toner particles, it is also simply referred to as “toner particles” or “toner”.

[2] Photophase transition material The compound (photophase transition material) that undergoes a solid-liquid phase transition by absorbing light according to the present invention is not particularly limited, but may be a compound that undergoes a cis-trans isomerization reaction by light absorption. preferable. Examples of the compound that undergoes the cis-trans isomerization reaction include an azobenzene derivative, a stilbene derivative, and an azomethine derivative, which are azobenzene derivatives or azomethine derivatives in that the toner image can be easily melted or softened even with a lower energy irradiation light amount. Is particularly preferable.

(1) A homocyclic compound or a heterocyclic compound having a diazo group (RN = N-R'), and typical examples thereof include an azobenzene derivative.

(2) A homocyclic compound or a heterocyclic compound having a vinylene group (RC = C-R'), and typical examples thereof include stilbene derivatives.

(3) A homocyclic compound or a heterocyclic compound having an azomethine group (RC = N-R'), and typical examples thereof include azomethine derivatives.

Among the above-mentioned photophase transition materials, an azobenzene derivative is preferable from the viewpoint of easily changing the toner image from the solid state to the liquid state even with a lower energy irradiation light amount.

(Azobenzene derivative)
Hereinafter, the details of the azobenzene derivative as a typical photophase transition material will be described.

Examples of the azobenzene derivative applicable to the present invention include an azobenzene derivative having a structure represented by the following general formula (1).

In the above general formula (1), R _{1 to} R ₁₀ are independently selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxy group, a halogeno group, a hydroxy group and a carboxy group, and R ₁ At least three of ~ R ₁₀ are groups selected from the group consisting of an alkyl group, an alkoxy group, a halogeno group, a hydroxy group and a carboxy group, and at this time, _{at least one of R 1 to} R ₅ has a carbon number of carbons. It is an alkyl group or an alkoxy group of 1 to 18, and _{at least one of R 6 to} R ₁₀ is an alkyl group or an alkoxy group having 1 to 18 carbon atoms.

Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group and an n-. Linear alkyl groups such as decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group; isopropyl group, isobutyl group, sec-butyl Group, tert-butyl group, isoamyl group, tert-pentyl group, neopentyl group, 1-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, 1-methylhexyl Group, tert-octyl group, 1-methylheptyl group, 2-ethylhexyl group, 2-propylpentyl group, 2,2-dimethylheptyl group, 2,6-dimethyl-4-heptyl group, 3,5,5-trimethyl Branched alkyl groups such as a hexyl group, a 1-methyldecyl group, and a 1-hexylheptyl group; can be mentioned.

Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group and an n-nonyloxy group. Group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, n-tridecyloxy group, n-tetradecyloxy group, n-pentadecyloxy group, n-hexadecyloxy group, etc. Alkoxy group in chain: isopropoxy group, tert-butoxy group, 1-methylpentyloxy group, 4-methyl-2-pentyloxy group, 3,3-dimethylbutyloxy group, 2-ethylbutyloxy group, 1- Methylhexyloxy group, tert-octyloxy group, 1-methylheptyloxy group, 2-ethylhexyloxy group, 2-propylpentyloxy group, 2,2-dimethylheptyloxy group, 2,6-dimethyl-4-heptyloxy Group, branched alkoxy group such as 3,5,5-trimethylhexyloxy group, 1-methyldecyloxy group, 1-hexylheptyloxy group;

The halogeno group refers to a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br) or an iodine group (-I).

In the above general formula (1), _{it is preferable that R 1} and R ₆ are independently alkyl groups or alkoxy groups having 1 to 18 carbon atoms. Above all, from the viewpoint of further improving the fixability of the image, _{it is preferable that R 1} and R ₆ are independently alkoxy groups having 1 to 18 carbon atoms. As described above, by having an alkyl group or an alkoxy group having 1 to 18 carbon atoms at the para position of the two benzene rings, the thermal motility of the molecule is increased, and as described above, the whole system is isotropically isotropic. Melting is likely to occur. At this time, _{the alkyl group or alkoxy group having 1 to 18 carbon atoms used in R 1} and R ₆ may be linear or branched, but a photophase transition is likely to occur. From the viewpoint of forming the structure of the rod-shaped molecule, it is preferably linear.

Among them, _{it is preferable that R 1} and R ₆ are independently alkyl groups or alkoxy groups having 6 to 12 carbon atoms. If R ₁ and R ₆ are an alkyl group or an alkoxy group within the above carbon number range, the alkyl-alkyl interaction acting between the molecules is relatively weak while having high thermal motility. Therefore, the cis-trans isomerization is more likely to proceed, and the softening rate by light irradiation and the fixability of the image are further improved.

Although R ₁ and R ₆ may be the same or different, they are preferably the same from the viewpoint of ease of synthesis.

In the general formula _(1), at least one of R 2 to R ₅ and _R 7 _{to R 10} is an alkyl group, an alkoxy group, a halogeno group, a group selected from the group consisting of hydroxy and carboxy groups (hereinafter , Simply referred to as a substituent). Having such a structure causes the formation of lattice defects which favor cis-trans isomerization, the expression of free volume, and the reduction of π-π interaction. As a result, cis-trans isomerization is more likely to proceed, and the softening rate by light irradiation and the fixability of the image are further improved. Among these, cis - from the viewpoint of ensuring the free volume required to trans isomerization, R ₂ to R ₅ and at least one alkyl of 1 to 4 carbon atoms which may have a branch of R ₇ to R ₁₀ It is preferably a group, an alkoxy group, or a halogeno group, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group, from the viewpoint of further improving the fixability of the image.

In the above general formula (1), _{the number of substituents in R 2 to} R ₅ and R _{7 to} R ₁₀ is preferably 1 to 8, and more preferably 1 to 6. Above all, from the viewpoint of not lowering the melting point of the azobenzene derivative too much and further improving the heat-resistant storage property of the toner, it is further preferably 1 to 4, and particularly preferably 1 to 3.

The _{positions where the substituents are present in R 2 to} R ₅ and R _{7 to} R _{10 are not particularly limited, but are R 2} , R ₄ , R ₇ and R ₉ (in other words, R ₁ ) of the above general formula (1). It is preferable that at least a substituent is present in any of the ortho-position and the ortho-position of R ₆ ), and at least a methyl group is present in any _{of R 2} , R ₄ , R ₇ and R _{9 of the above general formula (1).} It is more preferable to do so. Since the azobenzene derivative having such a structure has a higher softening rate due to light irradiation, the fixing property of the image is improved, and the melting point is appropriately increased, so that the heat-resistant storage property of the toner is also improved.

Examples of the azobenzene derivative applicable to the present invention include 4,4'-dihexylazobenzene, 4,4'-dioctylazobenzene, 4,4'-didecylazobenzene, 4,4'-didodecylazobenzene, and 4,4. _{4,4'-dialkylazobenzene; or 4,4'-bis (hexyloxy) in which R 1} and R ₆ of the general formula (1) such as ′ -dihexadecylazobenzene are alkyl groups having the same carbon number 1 to 18 ) azobenzene, 4,4'-bis _{(R 1} and octyloxy) azobenzene, 4,4'-bis (dodecyloxy) azobenzene, 4,4'-bis (hexadecyloxy) general formula, such as azobenzene (1) In _{4,4'-bis (alkoxy) azobenzene in which R 6} is an alkoxy group having the same carbon number of 1 to 18, the hydrogen atom added to the benzene ring is composed of an alkyl group, an alkoxy group, a halogeno group, a hydroxy group and a carboxy group. It is preferably a compound that is mono-substituted, di-substituted or tri-substituted with a group selected from the group. More specifically, the following azobenzene derivatives (1) to (13) can be mentioned. In the azobenzene derivatives shown below, the indication of the cis-trans state is omitted.

The method for synthesizing the azobenzene derivative is not particularly limited, and a conventionally known synthesis method can be applied.

<Synthesis Example 1: Synthesis of Azobenzene Derivative (1)>
For example, as shown in Reaction Scheme A below, 4-aminophenol and sodium nitrite are reacted under cooling to produce a diazonium salt, which is then reacted with o-cresol to synthesize Intermediate A (). The above azobenzene derivative (1) can be obtained by allowing n-bromohexane to act on the intermediate A (first step).

By changing the raw materials (4-aminophenol, o-cresol, n-bromohexane, etc.) used in the above reaction formula A to other compounds, R ₁ and R ₆ represented by the general formula (1) can be obtained. An azobenzene derivative which is an alkoxy group can be obtained. A person skilled in the art can synthesize a desired azobenzene derivative by appropriately making the above changes. Further, according to the above-mentioned production method, an azobenzene derivative having an asymmetric structure can be easily obtained.

<Synthesis Example 2: Synthesis of Azobenzene Derivative (4)>
The azobenzene derivative (4) can be obtained by changing o-cresol and n-bromohexane to 2-bromophenol and n-bromododecane, respectively, as shown in Reaction Scheme B below.

<Synthesis Example 3: Synthesis of Azobenzene Derivative (5)>
The azobenzene derivative (5) can be obtained by reacting the azobenzene derivative (4) with methanol in the presence of a Pd catalyst and a base as shown in the reaction formula C below.

<Synthesis Example 4: Synthesis of Azobenzene Derivative (6)>
As shown in the reaction formula D below, manganese dioxide, which is an oxidizing agent, is reacted with p-hexylaniline to synthesize 4,4'-dihexylazobenzene, and then N-bromosuccinimide is reacted to add methylboronic acid to Pd. The azobenzene derivative (6) can be obtained by reacting in the presence of a catalyst and a base.

By changing the raw materials (p-hexylaniline and methylboronic acid) used in the above reaction formula D to other compounds _{, an azobenzene derivative in which R 1} and R ₆ represented by the general formula (1) are alkyl groups can be obtained. Obtainable. A person skilled in the art can synthesize a desired azobenzene derivative by appropriately making the above changes.

The azobenzene derivative according to the present invention can be used alone or in combination of two or more.

(Azomethin derivative)
Specific examples of the azomethine derivative applicable to the present invention include the following azomethine derivative (A).

The method for synthesizing the azomethine derivative is not particularly limited, and a conventionally known synthetic method can be applied.

<Synthesis Example 5: Synthesis of azomethine derivative (A)>
As shown by the following reaction formula E, the azomethine derivative (A) can be obtained according to the following schemes 1 to 3.

In the above reaction formula E, in dimethylformamide (DMF), the raw materials 4-nitrophenol and 1-iodohexane (C ₆ H ₁₃ I) are heated under reflux using potassium carbonate (K ₂ CO _{3) to react.} 4-Hexyloxynitrobenzene can be obtained by washing the reaction solution with water, concentrating it, and purifying it (see Scheme 1 above).

Then, a mixed solvent of ethanol (EtOH) and tetrahydrofuran (THF), palladium on carbon (Pd / C catalyst) under relative 4- hexyloxy-nitrobenzene obtained in Scheme 1, with sealed hydrogen gas _{(H 2)} 4- (Hexyloxy) aniline can be obtained by stirring and reacting, removing the catalyst from the reaction solution, concentrating the solution, and then recrystallizing with ethanol (see Scheme 2 above).

Next, 4- (hexyloxy) aniline obtained in Scheme 2 and 5-methylthiophen-2-carboxyaldehyde were reacted in ethanol (EtOH) by heating and stirring, and the reaction solution was filtered to obtain the powder. Is washed with cold ethanol and recrystallized from methanol / ethanol to obtain the azomethine derivative (A) (see Scheme 3 above).

[3] Binder Resin The toner according to the present invention is characterized by being composed of toner particles containing a binder resin together with a photophase transition material that changes from a solid state to a liquid state by light irradiation described above.

When the toner according to the present invention contains a binder resin, the toner has an appropriate viscosity and bleeding when applied to paper is suppressed, so that fine line reproducibility and dot reproducibility are improved. It is generally known that toner particles having a substantially uniform particle size and shape can be produced by using a conventionally known emulsion-aggregation method as a toner production method.

For example, with the azobenzene derivative alone having the structure represented by the general formula (1), which is an example of the photophase transition material described above, toner particles can be produced by using salting out in the emulsification aggregation method due to the molecular structure. However, by using the binder resin together with the azobenzene derivative, it is possible to produce toner particles having a substantially uniform particle size and shape by using salting out in the emulsification / aggregation method. Therefore, the toner containing the azobenzene derivative and the binder resin can be easily applied by the toner for developing an electrostatic charge image.

In the present invention, as the binder resin, a resin generally used as a binder resin constituting a toner can be used without limitation. Specific examples thereof include styrene resin, acrylic resin, styrene / acrylic resin, polyester resin, silicone resin, olefin resin, amide resin, and epoxy resin. These binder resins can be used alone or in combination of two or more.

In the present invention, among these binder resins, when melted, the viscosity becomes low and the sharp melt property is high, and the amount of heat absorption based on the melting peak derived from the photophase transition material is measured by ΔH1 (J / g). From the viewpoint of not hindering the above, the binder resin is preferably a non-crystalline binder resin, and the non-crystalline binder resin applicable to the present invention includes styrene resin, acrylic resin, styrene / acrylic resin, and the like. And at least one selected from the group consisting of polyester resin, and more preferably containing at least one selected from the group consisting of styrene / acrylic resin and polyester resin.

Hereinafter, preferred binder resins such as styrene / acrylic resin and polyester resin will be described.

(Styrene / acrylic resin)
The styrene / acrylic resin referred to in the present invention is a resin formed by polymerizing at least a styrene monomer and a (meth) acrylic acid ester monomer. Here, the styrene monomer includes not only styrene _{represented by the structural formula of CH 2} = CH-C ₆ H ₅ but also a structure having a known side chain or functional group in the styrene structure.

The (meth) acrylic acid ester monomer has a functional group having an ester bond in the side chain. _{Specifically,} CH 2 = CHCOOR (R is an alkyl group) other acrylic acid ester monomer represented _by, methacrylic acid ester represented by _{CH 2 = C (CH 3)} COOR (R is an alkyl group) Contains vinyl ester compounds such as monomers.

Specific examples of the styrene monomer and the (meth) acrylic acid ester monomer capable of forming the styrene / acrylic resin are shown below, but the present invention is not limited to those shown below.

Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, and p-. Examples thereof include tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene and pn-dodecyl styrene.

Further, as the (meth) acrylic acid ester monomer, the following acrylic acid ester monomer and methacrylic acid ester monomer are typical, and as the acrylic acid ester monomer, for example, methyl acrylate. , Ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate and the like. Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate. , Lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate and the like.

These styrene monomer, acrylic acid ester monomer, or methacrylic acid ester monomer can be used alone or in combination of two or more.

Further, the styrene / acrylic copolymer includes the above-mentioned styrene monomer and the copolymer formed only of the (meth) acrylic acid ester monomer, as well as these styrene monomer and the (meth) acrylic acid. In addition to the ester monomer, some are formed by using a general vinyl monomer in combination. Hereinafter, vinyl monomers that can be used in combination when forming the styrene / acrylic copolymer referred to in the present invention will be illustrated, but the vinyl monomers that can be used in combination in the present invention are limited to those shown below. It's not a thing.

(1) Olefins: ethylene, propylene, isobutylene, etc. (2) Vinyl esters: vinyl propionate, vinyl acetate, vinyl benzoate, etc. (3) Vinyl ethers: vinyl methyl ether, vinyl ethyl ether, etc. (4) Vinyl ketones: Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc. (5) N-vinyl compounds: N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. (6) Others: Vinyl compounds such as vinylnaphthalene and vinylpyridine Kind, acrylic acid such as acrylonitrile, methacrylonitrile, acrylamide, or methacrylic acid derivative.

It is also possible to prepare a resin having a crosslinked structure by using a polyfunctional vinyl monomer. Furthermore, it is also possible to use a vinyl monomer having an ionic dissociation group in the side chain. Specific examples of the ionic dissociating group include a carboxyl group, a sulfonic acid group, a phosphoric acid group and the like. Specific examples of vinyl monomers having these ionic dissociating groups are shown below.

Specific examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, silicic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester and the like. ..

The method for forming the styrene / acrylic resin is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. If necessary, known chain transfer agents such as n-octyl mercaptan and n-octyl-3-mercaptopropionate may be used.

When the styrene / acrylic resin used in the present invention is formed, the contents of the styrene monomer and the acrylic acid ester monomer are not particularly limited, and the softening point temperature and the glass transition temperature of the binder resin are not particularly limited. It can be adjusted as appropriate from the viewpoint of control. Specifically, the content of the styrene monomer is preferably 40 to 95% by mass, more preferably 50 to 80% by mass, based on the entire monomer. The content of the acrylic acid ester monomer is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, based on the total amount of the monomer.

The method for forming the styrene / acrylic resin is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. Specific examples of the oil-soluble polymerization initiator include the following azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators.

Examples of the azo-based or diazo-based polymerization initiator include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, and 1,1'-azobis (cyclohexane-1). -Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

Examples of the peroxide-based polymerization initiator include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, 2, Examples thereof include 4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-tert-butylperoxycyclohexyl) propane, and tris- (tert-butylperoxy) triazine.

Further, when styrene / acrylic resin particles are formed by the emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

The polymerization temperature varies depending on the type of monomer and polymerization initiator used, but is preferably 50 to 100 ° C, more preferably 55 to 90 ° C. The polymerization time varies depending on the type of monomer and polymerization initiator used, but is preferably 2 to 12 hours, for example.

The styrene / acrylic resin particles formed by the emulsification polymerization method may have two or more layers made of resins having different compositions. In this case, as a production method, a polymerization initiator and a polymerizable monomer are added to a dispersion of resin particles prepared by an emulsion polymerization treatment (first-stage polymerization) according to a conventional method, and this system is polymerized. A multi-stage polymerization method in which treatment (second-stage polymerization) is performed can be adopted.

The glass transition temperature (Tg) of the styrene / acrylic resin is preferably in the range of 35 to 70 ° C., more preferably in the range of 40 to 60 ° C. from the viewpoint of fixability, heat-resistant storage property and the like. Tg can be measured by differential scanning calorimetry (DSC).

(Polyester resin)
The polyester resin is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid component) and a divalent or higher alcohol (polyhydric alcohol component). The polyester resin may be amorphous or crystalline.

The valences of the polyvalent carboxylic acid component and the polyhydric alcohol component are preferably 2 to 3 respectively, and particularly preferably 2 each. Therefore, as a particularly preferable form, the valences are 2 each (that is, dicarboxylic acid). Acid component, diol component) will be described.

Examples of the dicarboxylic acid component include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, and 1,10-decandicarboxylic acid. (Dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanediocarboxylic acid, 1,18 -Saturated aliphatic dicarboxylic acid such as octadecanedicarboxylic acid; unsaturated aliphatic dicarboxylic acid such as methylenesuccinic acid, fumaric acid, maleic acid, 3-hexendioic acid, 3-octendioic acid, dodecenylsuccinic acid; phthalic acid, Telephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylene diacetic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, anthracendicarboxylic acid, etc. , And the like, and these lower alkyl esters and acid anhydrides can also be used. The dicarboxylic acid component may be used alone or in combination of two or more.

In addition, trimellitic acid, pyromellitic acid and other trivalent or higher valent carboxylic acids, anhydrides of the above carboxylic acid compounds, alkyl esters having 1 to 3 carbon atoms and the like can also be used.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptane. Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecane Saturated aliphatic diols such as diols, 1,18-octadecanediols, 1,20-eicosanediols, neopentyl glycols; 2-butene-1,4-diols, 3-butene-1,4-diols, 2-butins. Unsaturated aliphatic diols such as -1,4-diol, 3-butin-1,4-diol, 9-octadecene-7,12-diol; bisphenols such as bisphenol A and bisphenol F, and addition of ethylene oxide thereof. Examples thereof include aromatic diols such as alkylene oxide adducts of bisphenols such as propylene oxide adducts, and derivatives thereof can also be used. The diol component may be used alone or in combination of two or more.

The method for producing the polyester resin is not particularly limited, and examples thereof include a method of polycondensing (esterifying) the polyvalent carboxylic acid component and the polyhydric alcohol component using a known esterification catalyst.

As catalysts that can be used in the production of polyester resins, alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, zirconium, Examples thereof include metal compounds such as germanium; phosphite compounds; phosphoric acid compounds; and amine compounds. Specifically, examples of the tin compound include dibutyltin oxide (dibutyltin oxide), tin octylate, tin dioctylate, and salts thereof. Examples of the titanium compound include titanium alkoxides such as tetranormal butyl titanate (Ti (On-Bu) ₄ ), tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; titanium tetra. Examples thereof include titanium chelates such as acetylacetonate, titanium lactate, and titanium triethanolaminate. Examples of the germanium compound include germanium dioxide and the like. Further, examples of the aluminum compound include polyaluminum hydroxide, aluminum alkoxide, tributylaluminate and the like. These may be used individually by 1 type or in combination of 2 or more type.

The polymerization temperature is not particularly limited, but is preferably 70 to 250 ° C. The polymerization time is also not particularly limited, but is preferably 0.5 to 10 hours. During the polymerization, the pressure inside the reaction system may be reduced, if necessary.

The glass transition temperature (Tg) of the polyester resin is preferably in the range of 35 to 70 ° C., more preferably in the range of 40 to 60 ° C. from the viewpoint of fixability, heat-resistant storage property and the like. Tg can be measured by differential scanning calorimetry (DSC).

The toner according to the present invention contains a binder resin, and the content ratio thereof is preferably in the range of photophase transition material: binder resin = 5:95 to 80:20 (mass ratio), 10:90 to 50: The range of 50 (mass ratio) is more preferable. Within the above range, the photophase transition of the photophase transition material is likely to occur, and the softening rate due to the light irradiation of the toner is sufficient. It also has excellent fine line reproducibility and dot reproducibility.

The toner according to the present invention containing the photophase transition material and the binder resin may have a single-layer structure or a core-shell structure. The type of the binder resin used for the core particles of the core-shell structure and the shell portion is not particularly limited.

[4] Other Toner Components The toner for static charge image development according to the present invention may contain each component in addition to the photophase transition material and the binder resin described above.

(Colorant)
The toner according to the present invention may contain a colorant. As the colorant, generally known dyes and pigments can be used.

Examples of the colorant for obtaining black toner include carbon black, magnetic material, iron / titanium composite oxide black, and the like, and examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. And so on. Examples of the magnetic material include ferrite, magnetite and the like.

Examples of the colorant for obtaining the yellow toner include C.I. I. Dyes such as Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, etc .; I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185 and the like.

Examples of the colorant for obtaining magenta toner include C.I. I. Dyes such as Solvent Red 1, 49, 52, 58, 63, 111, 122; C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222 and the like.

Examples of the colorant for obtaining cyan toner include C.I. I. Dyes such as Solvent Blue 25, 36, 60, 70, 93, 95; C.I. I. Pigment Blue 1, 7, 15, 6, 60, 62, 66, 76 and the like.

As the colorant for obtaining the toner of each color, one kind or a combination of two or more kinds can be used for each color.

The content ratio of the colorant is preferably in the range of 0.5 to 20% by mass and more preferably in the range of 2 to 10% by mass with respect to the total mass of the toner.

(Release agent)
The toner according to the present invention may contain a mold release agent. The release agent applicable to the present invention is not particularly limited, and various conventionally known waxes can be used.

Examples of the wax include low molecular weight polypropylene, polyethylene, oxidized low molecular weight polypropylene, polyolefin such as polyethylene, paraffin, synthetic ester wax, etc. In particular, synthetic ester wax is used because of its low melting point and low viscosity. It is preferable to use, and as the synthetic ester wax, it is particularly preferable to use behenyl behenate, glycerin tribehenate, pentaerythritol tetrabehenate and the like.

The content ratio of the release agent is preferably in the range of 1 to 30% by mass, and more preferably in the range of 3 to 15% by mass with respect to the total mass of the toner.

(Charge control agent)
The toner according to the present invention may contain a charge control agent. The charge control agent applicable to the present invention is not particularly limited as long as it is a substance that can give positive or negative charges by triboelectric charging and is colorless, and various conventionally known positively charged charges. A control agent and a negatively charged charge control agent can be used.

The content ratio of the charge control agent is preferably in the range of 0.01 to 30% by mass, and more preferably in the range of 0.1 to 10% by mass with respect to the total mass of the toner.

(External agent)
In order to improve the fluidity, chargeability, cleaning property, etc. of the toner, an external additive such as a fluidizing agent or a cleaning aid is added to the toner particles as a post-treatment agent, and the toner according to the present invention is added. May be configured.

Examples of the external additive include inorganic oxide particles such as silica particles, alumina particles and titanium oxide particles, inorganic stearic acid compound particles such as aluminum stearate particles and zinc stearate particles, strontium titanate particles and zinc titanate particles. Inorganic particles such as inorganic titanic acid compound particles such as. These can be used alone or in combination of two or more.

These inorganic particles may be surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like in order to improve heat-resistant storage properties and environmental stability.

The amount of these external additives added is preferably in the range of 0.05 to 5% by mass, more preferably in the range of 0.1 to 3% by mass, based on the total mass of the toner.

(Average particle size of toner)
In the toner according to the present invention, the average particle size is preferably in the range of 4 to 10 μm, more preferably in the range of 6 to 9 μm in terms of _{volume-based median diameter (D 50).} When the volume-based median diameter (D ₅₀ ) is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines, dots, etc. is improved, which is preferable.

In the present invention, the toner volume-based median diameter (D ₅₀ ) is a computer system (Beckman Coulter Co., Ltd.) equipped with data processing software "Software V3.51" on "Coulter Counter 3" (manufactured by Beckman Coulter Co., Ltd.). It is measured and calculated using a measuring device connected to Coulter Co., Ltd.).

Specifically, 0.02 g of the measurement sample (toner) is diluted 10 times with pure water in 20 mL of a surfactant solution (for the purpose of dispersing toner particles, for example, a neutral detergent containing a surfactant component). After adding to the agent solution) and acclimatizing, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is pipetted into a beaker containing "ISOTONII" (manufactured by Beckman Coulter, Inc.) in a sample stand until the indicated concentration of the measuring device reaches 8.0% by mass.

Here, by setting this concentration range, a reproducible measured value can be obtained. Then, in the measuring device, the number of measured particles is 25,000, the aperture diameter is set to 50 μm, and the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integration fraction is 50 from the largest. The particle size of% is defined as the volume-based median size (D ₅₀ ).

(Toner manufacturing method)
The production method applicable to the production of the toner according to the present invention is not particularly limited. For example, in the case of producing a toner containing a photophase transition material, a colorant and a binder resin, it is preferable to use a production method using an emulsification / agglutination method in which the particle size and shape can be easily controlled.

The manufacturing method using the arrival aggregation method is composed of the following steps.

(Step 1) Preparation step of each constituent particle dispersion liquid (1A) Preparation step of binding resin particle dispersion liquid for preparing dispersion liquid of binder resin particles (1B) Colorant particle dispersion for preparing dispersion liquid of colorant particles Liquid preparation step (1C) Preparation step of photophase transition material particle dispersion for preparing dispersion of photophase transition material particles (Step 2) Bundling resin particles, colorant particles and photophase transition material particles are present. A flocculant is added to an aqueous medium to promote salting, and at the same time, agglomeration and fusion are performed to form associative particles. (Step 3) Toner particles are formed by controlling the shape of the associative particles. Aging step (Step 4) Filtering and cleaning step of filtering toner particles from an aqueous medium and removing surfactants and the like from the toner particles (Step 5) Drying step of drying the washed toner particles (Step 6) ) It is preferable that the particles are composed of each step of the external additive addition step of adding the external additive to the dried toner particles.

Hereinafter, the details of (1A) to (1C), which are the steps of preparing each constituent particle dispersion liquid in the above (step 1), will be described.

(1A) Preparation Step of Bundling Resin Particle Dispersion Solution In this step, resin particles are formed by conventionally known emulsion polymerization or the like, and the resin particles are aggregated and fused to form binding resin particles. As an example, a dispersion liquid of the binder resin particles is prepared by putting the polymerizable monomers constituting the binder resin into an aqueous medium and dispersing them, and polymerizing these polymerizable monomers with a polymerization initiator. ..

Further, as a method for obtaining a binder resin particle dispersion solution, in addition to the method of polymerizing a polymerizable monomer with a polymerization initiator in the above-mentioned aqueous medium, for example, a dispersion treatment in an aqueous medium without using a solvent is performed. Alternatively, a method of dissolving the crystalline resin in a solvent such as ethyl acetate to prepare a solution, emulsifying and dispersing the solution in an aqueous medium using a disperser, and then performing a desolvation treatment and the like can be mentioned.

At this time, if necessary, the binding resin may contain a mold release agent in advance. Further, for dispersion, polymerization is appropriately carried out in the presence of a known surfactant (for example, anionic surfactant such as polyoxyethylene (2) sodium dodecyl ether sulfate, sodium dodecyl sulfate, dodecylbenzene sulfonic acid). Is also preferable.

The volume-based median diameter of the binder resin particles in the dispersion is preferably in the range of 50 to 300 nm. The volume-based median diameter of the binder resin particles in the dispersion can also be measured by a dynamic light scattering method using "Microtrack UPA-150" (manufactured by Nikkiso Co., Ltd.).

(1B) Preparation Step of Colorant Particle Dispersion Solution The preparation step of the colorant particle dispersion liquid is a step of preparing a dispersion liquid of colorant particles by dispersing the colorant in fine particles in an aqueous medium.

Dispersion of the colorant can be performed using mechanical energy. The median diameter based on the number of colorant particles in the dispersion is preferably in the range of 10 to 300 nm, and more preferably in the range of 50 to 200 nm. The median diameter based on the number of colorant particles can be measured using an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.).

(1C) Preparation Step of Photophase Transition Material Particle Dispersion Solution In this preparation step of the photophase transition material particle dispersion liquid, the photophase transition material particles are dispersed in an aqueous medium in the form of fine particles to obtain the photophase transition material dispersion particles. This is a step of preparing a dispersion. In preparing the photophase transition material particle dispersion, first, the photophase transition material emulsion is prepared. As a method for preparing an emulsion of a photophase transition material, for example, after obtaining a photophase transition material solution in which a photophase transition material, for example, an azobenzene derivative is dissolved in an organic solvent, the photophase transition material solution is placed in an aqueous medium. There is a method of emulsifying with.

The method for dissolving the photophase transition material in the organic solvent is not particularly limited, and there is a method in which the photophase transition material, for example, an azobenzene derivative is added to the organic solvent and stirred and mixed so that the azobenzene derivative is dissolved. The addition ratio of the photophase transition material is preferably in the range of 5 to 100 parts by mass, and more preferably in the range of 10 to 50 parts by mass with respect to 100 parts by mass of the organic solvent.

Next, the photophase transition material solution and the aqueous medium are mixed and stirred using a known disperser such as a homogenizer. As a result, the photophase transition material becomes droplets and is emulsified in the aqueous medium to prepare the photophase transition material emulsified liquid.

The addition ratio of the photophase transition material solution is preferably in the range of 20 to 200 parts by mass, and more preferably in the range of 50 to 100 parts by mass with respect to 100 parts by mass of the aqueous medium.

Further, the temperatures of the photophase transition material solution and the aqueous medium at the time of mixing the photophase transition material solution and the aqueous medium are in a temperature range below the boiling point of the organic solvent, preferably 20 to 80 ° C. It is within the range, more preferably in the range of 30 to 75 ° C. When the photophase transition material solution and the aqueous medium are mixed, the temperature of the photophase transition material solution and the temperature of the aqueous medium may be the same or different from each other, and are preferably the same.

The stirring conditions of the disperser are, for example, when the capacity is 1 to 3 L, the rotation speed is preferably in the range of 7,000 to 20,000 rpm, and the stirring time is in the range of 10 to 30 minutes. preferable.

The photophase transition material particle dispersion is prepared by removing the organic solvent from the photophase transition material emulsion. Examples of the method for removing the organic solvent from the emulsion of the photophase transition material include known methods such as blowing air, heating, depressurizing, or a combination thereof.

As an example, the emulsion of the photophase transition material has an initial amount of organic solvent in an atmosphere of an inert gas such as nitrogen, preferably in the range of 25 to 90 ° C, more preferably in the range of 30 to 80 ° C. The organic solvent is removed by heating until the range of 80 to 95% by mass is removed. As a result, the organic solvent is removed from the aqueous medium, and a light phase transition material particle dispersion liquid in which the photophase transition material particles are dispersed in the aqueous medium is prepared.

The mass average particle size of the photophase transition material particles in the photophase transition material particle dispersion is preferably in the range of 90 to 1200 nm. The mass average particle size of the photophase transition material particles is the viscosity when the photophase transition material is blended in an organic solvent, the blending ratio of the photophase transition material solution and water, and the dispersion when preparing the photophase transition material emulsion. It can be set within the above range by appropriately adjusting the stirring speed of the machine. The mass average particle size of the photophase transition material particles in the photophase transition material particle dispersion can be measured using an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.).

<Organic solvent>
The organic solvent used in the toner manufacturing process is not particularly limited as long as the photophase transition material according to the present invention can be dissolved. Specifically, esters such as ethyl acetate and butyl acetate, ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran, ketones such as acetone and methyl ethyl ketone, saturated hydrocarbons such as hexane and heptane, dichloromethane, dichloroethane, and tetra. Examples thereof include halogenated hydrocarbons such as carbon chloride.

Such an organic solvent can be used alone or in combination of two or more. Among these organic solvents, ketones and halogenated hydrocarbons are preferable, and methyl ethyl ketone and dichloromethane are more preferable.

<Aqueous medium>
The aqueous medium used in the toner manufacturing process is an aqueous medium containing water or water as a main component, a water-soluble solvent such as alcohols and glycols, and an optional component such as a surfactant and a dispersant. And so on. As the aqueous medium, a mixture of water and a surfactant is preferably used.

Examples of the surfactant include a cationic surfactant, an anionic surfactant, a nonionic surfactant and the like. Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like. Examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate and the like. Examples of the nonionic surfactant include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, and monodecanoyl. Examples include sucrose.

Such surfactants can be used alone or in combination of two or more. Among the surfactants, an anionic surfactant is preferably used, and more preferably sodium dodecylbenzenesulfonate is used.

The amount of the surfactant added is preferably 0.01 parts by mass or more and 10 parts by mass or less, and more preferably 0.04 parts by mass or more and 1 part by mass or less with respect to 100 parts by mass of the aqueous medium.

From the meeting step of (step 2) to the external additive addition step of (step 6) can be carried out according to various conventionally known methods.

The coagulant used in the (step 2) assembling step is not particularly limited, but one selected from metal salts is preferably used. Examples of the metal salt include monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; and trivalent metal salts such as iron and aluminum. And so on. Specific examples of the metal salt include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc., among which agglomerates in a smaller amount. It is particularly preferable to use a divalent metal salt because the above can be promoted. These can be used alone or in combination of two or more.

<Developer>
The toner according to the present invention may be used as a one-component magnetic toner containing a magnetic substance, mixed with a so-called carrier and used as a two-component developer, or a non-magnetic toner may be used alone. It is conceivable that any of them can be preferably used.

As the magnetic material, for example, magnetite, γ-hematite, various ferrites, or the like can be used.

As the carrier constituting the two-component developer, magnetic particles made of metals such as iron, steel, nickel, cobalt, ferrite and magnetite, and magnetic particles made of conventionally known materials such as alloys of these metals with metals such as aluminum and lead are used. Can be used.

As the carrier, it is preferable to use a coat carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, or a so-called resin dispersion type carrier in which magnetic powder is dispersed in a binder resin. The resin for coating is not particularly limited, and for example, an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, a polyester resin, a fluororesin, or the like is used. Further, the resin for forming the resin dispersion type carrier is not particularly limited, and known ones can be used. For example, acrylic resin, styrene / acrylic resin, polyester resin, fluororesin, phenol resin and the like are used. be able to.

The volume-based median diameter of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm. The median diameter based on the volume of the carrier can be typically measured by a laser diffraction type particle size distribution measuring device "HELOS" (manufactured by SIMPATEC) equipped with a wet disperser.

The amount of the toner mixed with the carrier is preferably 2 to 10% by mass, with the total mass of the toner and the carrier as 100% by mass.

[5] Image Forming Method and Image Forming Device The toner according to the present invention can be used in various known electrophotographic image forming methods. For example, it can be used in a monochrome image forming method or a full-color image forming method. In the full-color image forming method, a four-cycle image forming method composed of four types of color developing devices for each of yellow, magenta, cyan, and black and one photoconductor, and color developing for each color. It can be applied to any image forming method such as a tandem image forming method in which an image forming unit having an apparatus and a photoconductor is mounted for each color.

The image forming method of the present invention includes a step of forming a toner image made of the toner according to the present invention on a recording medium, and a step of irradiating the toner image with light to melt or soften the toner image. The wavelength of the light to be irradiated is preferably in the range of 280 to 480 nm.

<Outline of image forming device>
FIG. 1 is a schematic configuration diagram showing an image forming apparatus 100 used in the image forming method according to an embodiment of the present invention. However, the image forming apparatus used in the present invention is not limited to the following forms and illustrated examples. Although FIG. 1 shows an example of a monochrome image forming apparatus 100, the present invention can also be applied to a color image forming apparatus.

The image forming apparatus 100 is an apparatus for forming an image on the recording paper S as a recording medium, and includes an image reading device 71 and an automatic document feeder 72, and has an image on the recording paper S conveyed by the paper conveying system 7. An image is formed by the forming portion 10, the irradiation portion 40, the crimping portion 9, and the cooling portion 60.

Further, although the image forming apparatus 100 uses the recording paper S as the recording medium, the medium for which the image is formed may be other than the paper.

The image reading device 71 includes a scanning exposure device, an image sensor CCD, and an image processing unit 20. Then, the document d placed on the document table of the automatic document feeder 72 is conveyed to the image reading device 71, scanned and exposed by the optical system of the scanning exposure device, and read into the image sensor CCD. The analog signal photoelectrically converted by the image sensor CCD is input to the exposure device 3 of the image forming unit 10 after analog processing, A / D conversion, shading correction, image compression processing, etc. are performed in the image processing unit 20. To.

The paper transport system 7 includes a plurality of trays 16, a plurality of paper feed units 11, a transport roller 12, a transport belt 13, and the like. The tray 16 houses the recording paper S of a predetermined size, and operates the paper feeding unit 11 of the tray 16 determined in response to an instruction from the control unit 90 to supply the recording paper S. The transport roller 12 transports the recording paper S sent out from the tray 16 by the paper feed unit 11 or the recording paper S carried in from the manual paper feed unit 15 to the image forming unit 10.

In the image forming unit 10, the charging device 2, the exposure device 3, the developing unit 4, the transfer unit 5, the static elimination unit 6, and the cleaning unit 8 are arranged in this order around the photoconductor 1 along the rotation direction of the photoconductor 1. It is arranged and configured.

<Irradiation part>
Next, an irradiation unit 40 that softens the toner image by irradiating the toner image with light after forming the toner image on the recording paper will be described.

FIG. 2 is a partially enlarged view showing the peripheral configurations of the irradiation unit 40, the crimping unit 9, and the cooling unit 60 in the image forming apparatus 100.

In the image forming unit 10, the charging device 2, the exposure device 3, the developing unit 4, the transfer unit 5, the static elimination unit 6, and the cleaning unit 8 are arranged in this order around the photoconductor 1 along the rotation direction of the photoconductor 1. It is arranged and configured.

The photoconductor 1 is an image carrier having a photoconducting layer formed on its surface, and is configured to be rotatable in the direction of an arrow in FIG. 1 by a driving device (not shown). A thermo-hygrometer 17 for detecting the temperature and humidity in the image forming apparatus 100 is provided in the vicinity of the photoconductor 1.

The charger 2 uniformly charges the surface of the photoconductor 1, and uniformly charges the surface of the photoconductor 1.

The exposure device 3 is provided with a beam emitting source such as a laser diode, and by irradiating the surface of the charged photoconductor 1 with the beam light, the charge of the irradiated portion is eliminated, and the photoconductor 1 is statically charged according to the image data. Form an electro-latent image.

The developing unit 4 supplies the toner contained therein to the photoconductor 1, and creates a toner image based on the electrostatic latent image on the surface of the photoconductor 1.

The transfer unit 5 is arranged so as to face the photoconductor 1 via the recording paper S, and transfers the toner image to the recording paper S.

The static elimination unit 6 removes static electricity on the photoconductor 1 after transferring the toner image.

The cleaning unit 8 includes a blade 85. The blade 85 cleans the surface of the photoconductor 1 to remove the developer remaining on the surface of the photoconductor 1.

The irradiation unit 40 is a light source that irradiates the toner image formed on the recording paper S with light. Specifically, the irradiation unit 40 is arranged on the photoconductor 1 side with respect to the recording paper S surface nipped in the photoconductor 1 and the transfer roller 50. Further, the irradiation unit 40 is arranged between the nip position of the photoconductor 1 and the transfer roller 50 and the crimping unit 9 in the paper transport direction.

The irradiation unit 40 melts a compound (for example, an azobenzene derivative) that undergoes a phase transition due to light absorption contained in the developing agent, and is preferably in the range of 280 nm or more and less than 480 nm, more preferably 330 nm or more and less than 390 nm. Irradiate ultraviolet light with a wavelength within the range. The irradiation amount of ultraviolet light in the irradiation unit 40 is preferably in ^{the range of 0.1 to 200 J / cm 2} , more preferably in the range of 0.5 to 100 J / cm 2, and further preferably in the range of ^{1.0 to 50 J / cm 2.} It is within the range of cm ^2.

Examples of the irradiation unit 40 include a light emitting diode (LED), a laser light source, and the like. As a result, the toner image containing the polymer (A) is melted or softened, and the toner image is fixed on the recording paper S. The wavelength and the amount of light to be irradiated are as described above.

The crimping portion 9 is arbitrarily installed, and the recording paper S on which the toner image is transferred is subjected to a fixing process by applying pressure alone or heat and pressure by the pressure members 91 and 92, thereby recording. The image is fixed on the paper S. Further, when the toner image is cooled after the pressurizing step, it is cooled by the cooling unit 60. After that, the recording paper S on which the image is fixed is conveyed to the paper ejection unit 14 by the conveying roller, and is ejected from the paper ejection unit 14 to the outside of the machine.

Further, the image forming apparatus 100 includes a paper reversing unit 24. As a result, the heat-fixed recording paper S is conveyed to the paper reversing unit 24 in front of the paper ejection unit 14 and ejected by inverting the front and back sides, or the recording paper S whose front and back surfaces are inverted is again image-forming unit. It is possible to carry the image to 10 and form an image on both sides of the recording paper S.

Next, an image forming method using the image forming apparatus shown in FIG. 1 will be described below.

First, a uniform potential is applied to the photoconductor 1 by the charger 2 to charge the photoconductor 1, and then the light beam irradiated by the exposure device 3 is scanned on the photoconductor 1 based on the original image data to obtain an electrostatic latent image. Form.

Next, the developing unit 4 supplies a developing agent containing a compound that undergoes a phase transition due to light absorption onto the photoconductor 1.

When the recording paper S is conveyed from the tray 16 to the image forming unit 10 at the timing when the toner image carried on the surface of the photoconductor 1 reaches the position of the transfer roller 50 by the rotation of the photoconductor 1, the transfer roller 50 is transferred. Due to the applied transfer bias, the toner image on the photoconductor 1 is transferred onto the recording paper S nipped into the transfer member 50 and the photoconductor 1.

Further, the transfer roller 50 also serves as a pressurizing member, and while transferring the toner image from the photoconductor 1 to the recording paper S, the toner image is surely adhered to the recording paper S.

After the toner image is transferred to the recording paper S, the blade 85 of the cleaning unit 8 removes the developer remaining on the surface of the photoconductor 1.

In this way, the recording paper S on which the toner image is transferred is conveyed to the irradiation unit 40 and the crimping unit 9 by the transfer belt 13.

Then, the irradiation unit 40 irradiates the toner image transferred onto the recording paper S with light (preferably light in the range of 280 to 480 nm). By irradiating the toner image on the recording paper S with light by the irradiation unit 40, the toner image can be melted and softened, so that the toner image can be fixed to the recording paper S.

When the recording paper S on which the toner image is held reaches the crimping portion 9 by the transport belt 13, the recording paper S on which the toner image is formed is crimped by the pressure member 91 and the pressure member 92. Since the toner image is softened by light irradiation by the irradiation unit 40 before being pressed by the pressure-bonding portion 9, the toner image on the recording paper S can be pressure-bonded with lower energy.

The pressure when pressurizing the toner image is as described above. The pressurizing step may be performed before or at the same time as the step of irradiating light to soften the toner image, or may be performed after the step. From the viewpoint that the toner image in a pre-softened state can be pressurized and the image intensity can be easily increased, it is preferable that the pressurizing step is performed after light irradiation.

The pressurizing member 91 can heat the toner image on the recording sheet S when the recording sheet S passes between the pressurizing member 91 and the pressurizing member 92. The toner image softened by light irradiation is further softened by this heating, and as a result, the fixability (image intensity) of the toner image on the recording paper S is further improved.

The heating temperature of the toner image is as described above. The heating temperature of the toner image (surface temperature of the toner image) can be measured by a non-contact temperature sensor. Specifically, for example, a non-contact temperature sensor may be installed at a position where the recording medium is discharged from the pressurizing member, and the surface temperature of the toner image on the recording medium may be measured.

The toner image crimped by the pressurizing member 91 and the pressurizing member 92 is solidified and fixed on the recording paper S.
Further, in the present invention, it is preferable to have a step of cooling the toner image after the heating step, and the toner image is cooled and fixed by the cooling unit 60. As the cooling means, it is preferable to use a cooling fan (Cooling unit 60 in FIG. 2) which is a non-contact means, a cooling roller which is a contact means, or the like. The cooling temperature is adjusted as appropriate, but is preferably in the range of 5 to 30 ° C, more preferably in the range of 5 to 20 ° C.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

<Synthesis Example 1: Synthesis of compound (A1)>
After adding 75 mL of 2.4N hydrochloric acid to 4-aminophenol (6.54 g, 60 mmol), add a solution of sodium nitrite (4.98 g, 72 mmol) in 6 mL of distilled water while cooling and stirring at 0 ° C. , Stirring was continued at 0 ° C. for 60 minutes. A mixed solution of o-cresol (6.48 g, 60 mmol) and 24 mL of a 20% aqueous sodium hydroxide solution was added to this solution, and the mixture was stirred for 20 hours. The precipitated precipitate was filtered and the solid was washed with water. The obtained solid was purified by silica gel column chromatography using a mixed solution of ethyl acetate and hexane as a developing solvent, and recrystallized from a mixed solvent of acetone and hexane to obtain an intermediate (first step).
To this intermediate (2.28 g, 10 mmol), 100 mL of DMF, 1-bromohexane (9.9 g, 60 mmol) and potassium carbonate (6.9 g, 50 mmol) were added, and the mixture was stirred at 80 ° C. for 2 hours and then at room temperature for 20 hours. Stirring was continued. The solvent was evaporated under reduced pressure, extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. After filtering this, the solvent was distilled off under reduced pressure, and the obtained solid was purified by silica gel column chromatography using a mixed solution of ethyl acetate and hexane as a developing solvent to obtain the compound (A1) which is an azobenzene derivative. Obtained (second stage).

<Synthesis Example 2: Synthesis of compound (A2)>
Compound (A2) was obtained in the same manner except _{that C 6} H ₁₃ Br in the _{reaction formula was changed to C 8} H ₁₅ Br in Synthesis Example 1.

<Synthesis Example 3: Synthesis of compound (A3)>
4-Nitrophenol (4.2 g, 30.2 mmol), 1-iodohexane (19.2 g, 90.6 mmol), potassium carbonate (19.2 g, 90.6 mmol) in a 100 ml 4-headed flask equipped with a cooling tube, nitrogen introduction tube, and thermometer. 10.4 g, 75.5 mmol) and 50 ml of dimethylformamide were added and refluxed by heating. The reaction mixture was washed with water, concentrated, and purified by column chromatography (ethyl acetate: heptane = 1: 9 (volume ratio)) to obtain 5.8 g (yield 86%) of 4- (hexyloxy) nitrobenzene. (First stage).

In a 500 ml Erlenmeyer flask, put 4- (hexyloxy) nitrobenzene (5.8 g, 26.1 mmol) and palladium carbon (0.12 g, 258 mmol), put 60 ml each of ethanol and tetrahydrofuran, and add hydrogen (H ₂ ). Stirred while encapsulating. Palladium on carbon was removed from the reaction solution, the obtained solution was concentrated, and then recrystallized from ethanol to obtain 3.8 g (yield 75%) of 4- (hexyloxy) aniline (second step).

4- (Hexyloxy) aniline (1.1 g, 5.7 mmol) and 5-methylthiophene-2-carboxyaldehyde (0.7 g,) in a 100 ml 4-headed flask equipped with a cooling tube, nitrogen introduction tube, and thermometer. 5.7 mmol) and 20 ml of ethanol were added, and the mixture was heated and stirred at 50 ° C. The reaction solution was suction filtered, and the obtained powder was washed with cooling ethanol. Further, recrystallization was carried out with methanol / ethanol to obtain 0.75 g (yield 45%) of the target compound (A3), which is an azomethine derivative.

(Preparation of compound (A1) particle dispersion liquid 1)
80 parts by mass of dichloromethane and 20 parts by mass of compound (A1) were mixed and stirred while heating at 50 ° C. to obtain a liquid containing compound (A1). To 100 parts by mass of this solution, a mixed solution of 99.5 parts by mass of distilled water warmed to 50 ° C. and 0.5 parts by mass of a 20% by mass sodium dodecylbenzene sulfonate aqueous solution was added. Then, it was emulsified by stirring at 16000 rpm for 20 minutes with a homogenizer (manufactured by Heidolph) equipped with a shaft generator 18F to obtain an emulsified solution containing compound (A1) particles.

Then, the solvent was removed under reduced pressure to obtain a compound (A1) particle dispersion liquid 1. Compound (A1) The volume-based median diameter of compound (A1) in the particle dispersion 1 was 145 nm.

(Preparation of compound (A2) particle dispersion liquid 2 and compound (A3) particle dispersion liquid 3)
The compound (A2) particle dispersion 2 and the compound (A3) particle dispersion 3 were prepared in the same manner as in the preparation of the compound (A1) particle dispersion.

[Preparation of binder resin]
(Preparation of styrene / acrylic resin particle dispersion liquid 1B containing styrene / acrylic resin 1b)
(First stage polymerization)
A solution prepared by dissolving 8 parts by mass of sodium dodecyl sulfate in 3000 parts by mass of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device, and stirred at a stirring speed of 230 rpm under a nitrogen stream. However, the internal temperature was raised to 80 ° C. After the temperature was raised, a solution prepared by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added to bring the liquid temperature to 80 ° C. again, and 480 parts by mass of styrene, 250 parts by mass of n-butyl acrylate, 68 parts of methacrylic acid. A polymerizable monomer solution consisting of 0 parts by mass and 5.0 parts by mass of n-octyl mercaptan was added dropwise over 1 hour, and then polymerized by heating at 80 ° C. for 2 hours and stirring to carry out polymerization, and styrene / acrylic resin particles (1b). ) Was prepared as a styrene / acrylic resin particle dispersion (1B).

(Second stage polymerization)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device, a solution prepared by dissolving 2 parts by mass of polyoxyethylene-2-dodecyl ether sodium sulfate in 3000 parts by mass of ion-exchanged water was charged and heated to 70 ° C. After heating, 260 parts by mass of the above styrene / acrylic resin particle dispersion solution (1B) and 201 parts by mass of styrene, 93 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methacrylic acid (MAA) and n-octyl mercaptan 4. A mechanical disperser "CREARMIX" having a circulation path is added by adding a polymerizable monomer solution in which 2 parts by mass and 50 parts by mass of paraffin wax "HNP-11" (manufactured by Nippon Seiwa Co., Ltd.) are dissolved at 70 ° C. -Mixed and dispersed for 1 hour with (manufactured by Technique) to prepare a dispersion containing emulsified particles (oil droplets).

Next, an initiator solution prepared by dissolving 6 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added to this dispersion, and the system was heated and stirred at 80 ° C. for 1 hour to carry out polymerization. A styrene / acrylic resin particle dispersion (2B) containing styrene / acrylic resin particles (2b) was prepared.

(Third stage polymerization)
A solution prepared by dissolving 6 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water was added to the above styrene / acrylic resin particle dispersion (2B), and under a temperature condition of 82 ° C., 435 parts by mass of styrene, n-. A polymerizable monomer solution consisting of 130 parts by mass of butyl acrylate, 33 parts by mass of methacrylic acid and 8.4 parts by mass of n-octyl mercaptan was added dropwise over 1 hour. After completion of the dropping, polymerization was carried out by heating and stirring for 2 hours, and then the mixture was cooled to 28 ° C. to obtain a styrene / acrylic resin particle dispersion liquid (3B) containing styrene / acrylic resin 3b. When the particle size of the styrene / acrylic resin particles in the dispersion was measured by a dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.), it was 120 nm in terms of volume-based median diameter. .. Moreover, when the glass transition point Tg of this styrene / acrylic resin 3b was measured, it was 42 ° C.

(Preparation of carbon black dispersion)
11.5 parts by mass of sodium n-dodecyl sulfate was dissolved in 1600 parts by mass of pure water, and 25 parts by mass of carbon black "Mogal L (manufactured by Cabot Corporation)" was gradually added, and then "Clearmix (registered trademark) W" was added. A carbon black dispersion was prepared using "Motion CLM-0.8 (manufactured by M Technique Co., Ltd.)".

<Manufacturing of toner 1>
450 parts by mass of the styrene / acrylic resin particle dispersion liquid (3B) prepared above, 900 parts by mass of ion-exchanged water, and 40 parts by mass of the carbon black dispersion liquid in terms of solid content, a stirrer, temperature sensor , And put into a reactor equipped with a cooling tube. The temperature inside the container was maintained at 30 ° C., and a pH was adjusted to 10 by adding a 5 mol / liter aqueous sodium hydroxide solution. Then, 150 parts by mass of the compound (A1) particle dispersion liquid 1 was added in terms of solid content, and the pH was adjusted to 10 again. Next, an aqueous solution prepared by dissolving 50 parts by mass of magnesium chloride hexahydrate in 50 parts by mass of ion-exchanged water was added dropwise over 10 minutes under stirring, and then the temperature was raised, and this system was heated over 60 minutes. The temperature was raised to ° C., and the particle growth reaction was continued while maintaining 70 ° C. In this state, the particle size of the associated particles was measured with "Multisizer 3" (manufactured by Beckman Coulter, Inc.), and when the median diameter (D50) on a volume basis reached 6.5 μm, 150 parts by mass of sodium chloride. Was added to 600 parts by mass of ion-exchanged water to stop particle growth. After stirring at 70 ° C. for 1 hour, the temperature was further raised, and the mixture was heated and stirred at 75 ° C. to promote the fusion of particles. Then, the mixture was cooled to 30 ° C. to obtain a dispersion of toner particles.

Next, the operation of solid-liquid separation, redispersion of the dehydrated toner cake in ion-exchanged water, and solid-liquid separation was repeated three times for washing, and then dried at 40 ° C. for 24 hours to obtain toner matrix particles.

To the obtained toner matrix particles, 1% by mass of hydrophobic silica (number average primary particle size: 12 nm) and 0.3% by mass of hydrophobic titania (number average primary particle size: 20 nm) were added, and a Henschel mixer (registered) was added. Toner 1 composed of toner particles 1 was obtained by mixing using (trademark).

<Preparation of toner 2 and toner 3>
In the preparation of the toner 1, the toner 2 containing the toner particles 2 was obtained in the same manner except that the amount of the compound (A1) particle dispersion 1 added was 150 parts by mass. Further, the toner 3 containing the toner particles 3 was obtained in the same manner except that the amount of the compound (A1) particle dispersion 1 added was 100 parts by mass.

<Preparation of toner 4 and toner 5>
In the preparation of the toner 1, the toner containing the toner particles 4 is prepared in the same manner except that the compound (A1) particle dispersion 1 is changed to the compound (A2) particle dispersion 2 and the compound (A3) particle dispersion 3. Toner 5 containing 4 and toner particles 5 was obtained.

<Preparation of toner 6>
In the preparation of the toner 1, the toner 6 containing the toner particles 6 was obtained in the same manner except that the compound (A1) particle dispersion 1 was not added.

<Preparation of developer>
Developers (1) to (6) are mixed by adding ferrite carriers coated with a silicone resin and having a volume average particle size of 35 μm to toners 1 to 6 so that the toner particle concentration is 7% by mass. ) Were prepared respectively.

"Evaluation method"
In bizhub PRESS C1070 (Konica Minolta Co., Ltd. system), the fixing device was modified and a light irradiation device was introduced, and the developer obtained above was used in a normal temperature and humidity environment (temperature 20 ° C, humidity 50% RH). ) Was evaluated.

In addition, a control unit is added to control the integrated light amount to be irradiated to the position corresponding to the image area corresponding to the image data and the integrated light amount to be irradiated to the position corresponding to the position other than the image area, and the light irradiation device is controlled. The integrated light intensity can be changed according to the instructions of the department.

An image with an adhesion amount of 5.0 g / m2 and a size of 50 mm × 50 mm was output on A4 size high-quality paper “CF paper; Konica Minolta Co., Ltd.). The print area ratio at this time was 4.1%. The conditions for irradiating light to the image area and areas other than the image area (maximum emission wavelength, integrated light amount, illuminance, irradiation time of the irradiated light) are as shown in Table I. The light to be irradiated is shown in Table I. An LED light source that irradiates light in the wavelength region of the maximum emission wavelength of ± 20 nm was used.

As the fixing device, four types of devices were used (see FIG. 1).

No. Reference numeral 1 denotes a crimping portion 9 and an irradiation portion 40.

No. Reference numeral 2 denotes a crimping portion 9, and the temperature of the pressurizing member 91 is 20 ° C.

No. Reference numeral 3 denotes a crimping portion 9, and the temperature of the pressurizing member 91 is 60 ° C.

No. Reference numeral 4 denotes a crimping portion 9, the temperature of the pressurizing member 91 is 60 ° C., and further includes a cooling portion 60 for blowing cooling air at 10 ° C.

The test was conducted under the conditions shown in Table I under the conditions of Examples 1 to 12 and Comparative Examples 1 to 5.

<Energy saving>
The integrated light intensity per sheet of A4 paper under the above conditions was used as an evaluation index, and it was judged that less than 75 kJ / (1 sheet of A4) was excellent in energy saving.
⊚: less than 40 kJ 〇: 40 kJ or more, less than 75 kJ ×: 75 kJ or more

<Fixability of image area in image data>
The image data portion of the obtained image was rubbed 10 times with a pressure of 10 kPa with (JK Wiper (registered trademark); Nippon Paper Crecia Co., Ltd.), and the image was visually evaluated. 〇 or more was judged to be acceptable.

◎: No image peeling 〇: Partial peeling is seen in the image, but there is no problem in practical use ×: Peeling is conspicuous in the entire image and cannot be used in practical use <Fixability other than the image area in the image data: Scattered toner Evaluation ＞
A pressure of 10 kPa was applied to a portion other than the image data portion of the obtained image (JK Wiper (registered trademark); Nippon Paper Crecia Co., Ltd.) and rubbed three times, and the coloring of the JK wiper due to toner stains was visually evaluated. 〇 or higher was set as the pass level.

⊚: No coloring is observed 〇: Slightly colored is observed ×: Dark coloring is observed The above level composition and evaluation results are summarized in Table I.

From Table I, it can be seen that Examples 1 to 12, which are the image forming methods of the present invention, are superior to Comparative Examples 1 to 5 in energy saving, fixing property in the image area, and fixing property other than the image area. ..

1 Photoreceptor 2 Charger 3 Exposed device 4 Developing unit 5 Transfer unit 6 Static elimination unit 7 Paper transfer system 8 Cleaning unit 9 Crimping unit 10 Image forming unit 11 Paper feed unit 12 Transport roller 13 Transport belt 14 Paper discharge section 15 Manual paper feed 16 Tray 20 Image processing unit 24 Paper reversing unit 40 Irradiating unit 50 Transfer roller 60 Cooling unit 71 Image reader 72 Automatic document feeder 85 Blade 90 Control unit 91, 92 Pressurizing member 100 Image forming device

Claims (11)

An image forming method for photofixing at least a toner image formed by using toner.
The toner contains a compound that undergoes a solid-liquid phase transition by absorbing light.
A developing process that forms a toner image using the toner based on image data,
The step of transferring the toner image onto a recording medium and
The toner image transferred onto the recording medium is irradiated with light to melt or soften the toner image, and the toner image is melted or softened.
The integrated light amount of the light to be applied to a position corresponding to the image area on the recording medium corresponding to the image data is A [J / cm ² ], and the integrated light to be applied to a position other than the image area is integrated. An image forming method characterized in that the following equation (1) is satisfied when the amount of light is B [J / cm ^2].
Equation (1) A ≧ B The image forming method according to claim 1, wherein the integrated light amounts A and B satisfy the following formula (2).
Equation (2) A ≧ 2 × B The image forming method according to claim 2, wherein the integrated light amounts A and B satisfy the following formula (3).
Equation (3) A ≧ 5 × B ^{The illuminance [W / cm 2} ] differs by 0.1 [W / cm ² ] or more between the light irradiating the position corresponding to the image area and the light irradiating the position other than the image area. The image forming method according to any one of claims 1 to 3. Claim 1 is characterized in that the irradiation time (sec) differs by 0.01 (sec) or more between the light irradiating the position corresponding to the image area and the light irradiating the position other than the image area. The image forming method according to any one of claims 3 to 3. Claims 1 to 5 are characterized in that, in the step of irradiating the light to melt or soften the toner image, the irradiated light is monochromatic synchrotron radiation having a maximum emission wavelength in the range of 280 to 480 nm. The image forming method according to any one of the above. The image forming method according to any one of claims 1 to 6, wherein the compound that undergoes a solid-liquid phase transition is an azobenzene derivative or an azomethine derivative. The image forming method according to any one of claims 1 to 7, further comprising a step of further pressurizing the softened toner image. The image forming method according to claim 8, further comprising a step of further heating the toner image in the pressurizing step. The image forming method according to claim 9, further comprising a step of cooling the toner image after the heating step. An image forming apparatus for light-fixing at least a toner image formed by using toner.
The toner is a toner containing a compound that undergoes a solid-liquid phase transition by absorbing light.
A developing unit that forms a toner image using the toner based on image data,
A transfer unit that transfers the toner image onto a recording medium,
An irradiation unit that irradiates the toner image transferred onto the recording medium with light, and an irradiation unit.
^{Let A [J / cm 2} ] be the integrated amount of light emitted to a position corresponding to the image area on the recording medium corresponding to the image data, and the integrated amount of light to be applied to a position other than the image area. When B [J / cm ² ] is set to, a light irradiation control unit that controls the light to be irradiated so as to satisfy the following equation (1), and a light irradiation control unit.
An image forming apparatus characterized by having.
Equation (1) A ≧ B

Images