JP6841000B2 - Image forming device and image forming method - Google Patents

Description

The present invention relates to an image forming apparatus and an image forming method.

Conventionally, an electrostatic latent image formed on a photoconductor is developed with toner to form a toner image, the formed toner image is transferred to paper, and the transferred toner image is heated and fixed on the paper. An electrophotographic image forming apparatus for forming an image is known. In such an image forming apparatus, in order to fix the toner image on the paper by heat fixing, it is necessary to heat the toner to a high temperature and melt it once. Therefore, there is a limit to energy saving.

In recent years, in order to save energy at the time of image formation, improve operability, and expand the types of compatible media, a system that is fixed by an external stimulus different from heat has been proposed. In particular, a photofixing system that is relatively easy to adapt to an electrophotographic process has attracted attention, and a developing agent (light-melted toner) that is softened by light has been reported.

For example, Patent Document 1 discloses a developer containing a binder resin, a colorant, and an additive, and the additive contains a compound that undergoes a cis-trans isomerization reaction due to light absorption and undergoes a phase transition. There is. Further, as a fixing method using such a developer, in Patent Document 1, light is applied to a toner image transferred to paper, a compound that undergoes a phase transition by light absorption is melted, and then light is irradiated again. Then, a technique for fixing the toner image on the paper by coagulating the compound is disclosed.

Further, Patent Document 2 discloses an image forming apparatus in which a developer containing a compound that undergoes a cis-trans isomerization reaction by light absorption and undergoes a phase transition is used. As an example of such an image forming apparatus, in Patent Document 2, when forming an image on a recording sheet made of a transparent resin, light is emitted toward a nip position, which is a position where a transfer belt is sandwiched between a photoconductor and a transfer roller. An image forming apparatus including an exposure apparatus for irradiating light has been proposed.

Japanese Unexamined Patent Publication No. 2014-191078 Japanese Unexamined Patent Publication No. 2014-191707

However, the techniques described in Patent Documents 1 and 2 have problems that the productivity is low and the image fixability is also poor because the softening rate of the toner by light irradiation is not sufficient.

Therefore, an object of the present invention is to provide a means for improving the softening rate and image fixability of a toner containing a compound that undergoes a phase transition from a solid to a liquid by absorbing light.

The present inventors have accumulated extensive research. As a result, they have found that the above problem can be solved by an image forming apparatus provided with a heating means for heating the toner image before irradiation with ultraviolet rays, and have completed the present invention.

That is, the present invention is an image forming apparatus using a toner containing a compound and a binder resin that undergoes a phase transition from a solid to a liquid by absorbing light having a wavelength of 300 nm or more and less than 400 nm, and is on a recording medium. A heating means for heating the toner image formed in the above, a first light irradiation means for irradiating the toner image heated by the heating means with light having a wavelength of 300 nm or more and less than 400 nm, and the first light irradiation means. 400 nm or more and 800 nm or less with respect to the pressurizing means for pressurizing the toner image irradiated with light by the light irradiating means to press it against the recording medium and the toner image crimped to the recording medium by the pressurizing means An image forming apparatus comprising a second light irradiating means for irradiating light having a wavelength of.

According to the present invention, there is provided a means for improving the softening rate and image fixability of a toner containing a compound that undergoes a phase transition from a solid to a liquid by absorbing light.

It is a schematic block diagram which shows the image forming apparatus by one Embodiment of this invention. It is a schematic block diagram of the irradiation part in an image forming apparatus.

The present invention is an image forming apparatus using a toner containing a compound and a binder resin that undergoes a phase transition from a solid to a liquid by absorbing light having a wavelength of 300 nm or more and less than 400 nm, and is formed on a recording medium. A heating means for heating the heated toner image, a first light irradiation means for irradiating the toner image heated by the heating means with light having a wavelength of 300 nm or more and less than 400 nm, and the first light irradiation. The wavelength of 400 nm or more and 800 nm or less with respect to the pressurizing means for pressurizing the toner image irradiated with light by the means and pressing the toner image against the recording medium and the toner image crimped to the recording medium by the pressurizing means. An image forming apparatus comprising a second light irradiating means for irradiating light having the above. By using such an image forming apparatus, the softening rate of the toner is improved, and the fixability of the image is improved.

The details of the reason why the above effect can be obtained by the image forming apparatus of the present invention are unknown, but it is considered to be due to the following mechanism. However, the following mechanism is speculative, and its correctness does not affect the technical scope of this embodiment.

The toner used in the present invention is characterized by containing a compound that undergoes a phase transition from a solid to a liquid by absorbing light (hereinafter, also referred to as a photophase transition compound). There are few reports of such photophase transition compounds, and the mechanism of photophase transition has not been sufficiently clarified, and the mechanism of softening of toner containing the photophase transition compound has also been sufficiently clarified. Absent.

Therefore, as a result of diligently studying the photosoftening mechanism of the toner containing the photophase transition compound and the binder resin, the present inventors use an image forming apparatus provided with a heating means for heating the toner image before irradiation with ultraviolet rays. As a result, it was newly found that the softening rate of the toner is improved and the fixability of the image is improved.

By heating the toner before irradiation with ultraviolet rays, the cis-trans isomerization reaction of the photophase transition compound is further promoted, and the photophase transition compound liquefied by the isomerization reaction is compatible with the binder resin as described above. It is considered that the effect is exhibited. The cis-trans isomerization reaction is a phenomenon peculiar to the photophase transition compound, and it is said that the photophase transition compound is liquefied by mixing a certain amount of the cis form generated by irradiation with ultraviolet rays in the crystal structure of the trans form. It is considered that heating reaches the mixed state faster, that is, the softening rate is improved. Further, it is considered that the binding resin has increased molecular motion due to heating, and is more easily compatible with the liquefied photophase transition compound. In the absence of heating, the binder resin and the liquefied photophase transition compound are in a state of being almost incompatible with each other because the interaction is not sufficiently expressed, and it is considered that the photosoftening phenomenon occurs only in the photophase transition compound. However, in the image forming apparatus of the present invention, the photosoftening phenomenon occurs only in the photophase transition compound due to the promotion of the compatibility between the photophase transition compound and the binder resin by heating the toner image. It is considered that the fixability is further improved because the toner is expressed as a whole.

Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described. In addition, in this specification, "X to Y" indicating a range means "X or more and Y or less". Further, in the present specification, unless otherwise specified, the operation and the measurement of physical properties are performed under the conditions of room temperature (20 to 25 ° C.) / relative humidity of 40 to 50% RH.

[Image forming device]
FIG. 1 is a schematic configuration diagram showing an image forming apparatus 100 according to an embodiment of the present invention. However, the image forming apparatus of 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 a device that forms an image on the recording paper S as a recording medium, includes an image reading device 71 and an automatic document feeder 72, and has an image with respect to the recording paper S conveyed by the paper conveying system 7. An image is formed by the forming portion 10, the heating portion 30, the first irradiation portion 40a, the crimping portion 9, and the second irradiation portion 40b. Hereinafter, when the first irradiation unit 40a and the second irradiation unit 40b are collectively referred to, they are referred to as an irradiation unit 40.

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 document d placed on the platen of the automatic document feeder 72 is scanned and exposed by the optical system of the scanning exposure device of the image reading device 71 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.

The photoconductor 1 which is an image carrier 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 faces 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 surface of the photoconductor 1 is cleaned by the blade 85 to remove the developer remaining on the surface of the photoconductor 1.

The recording paper S on which the toner image is formed (transferred) is conveyed to the crimping portion 9 by the conveying belt 13. The crimping portion 9 is arbitrarily installed, and the recording paper S on which the toner image is formed (transferred) is subjected to a fixing treatment by applying pressure alone or heat and pressure by the pressure members 91 and 92. As a result, the image is fixed on the recording paper S. 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, and the recording paper S that has been heat-fixed is conveyed to the paper reversing unit 24 in front of the paper ejection unit 14, and the front and back sides are inverted and ejected. Alternatively, the recording paper S whose front and back sides are reversed can be conveyed to the image forming unit 10 again to form an image on both sides of the recording paper S.

<Irradiation part>
FIG. 2 is a schematic configuration diagram of the irradiation unit 40 in the image forming apparatus 100.

The image forming apparatus 100 according to the embodiment of the present invention includes a heating unit (heating means) 30, and further includes a first irradiation unit (first light irradiation means) 40a and a second irradiation unit (second light irradiation means). ) 40b is provided with an irradiation unit 40.

The heating unit (heating means) 30 heats the toner image formed on the recording medium before irradiation with ultraviolet rays. As the device constituting the heating unit (heating means) 30, either a non-contact type or a contact type can be used, and more specific examples thereof include an infrared heater, an infrared laser, and a contact type heat fixing device. ..

The heating unit (heating means) 30 preferably heats the surface of the toner image to a temperature equal to or higher than the glass transition temperature of the toner, and more preferably to a temperature equal to or higher than the glass transition temperature of the toner + 0.5 ° C. Further, the heating means preferably heats the surface of the toner image to a temperature lower than the softening point of the toner, and more preferably to a temperature of −5 ° C. or lower of the softening point of the toner. Within such a heating temperature range, the molecular motion of the binder resin is increased, the compatibility with the photophase transition compound is promoted, the toner is not excessively melted, and the energy used is suppressed. The softening rate and fixability of the toner are further improved.

The surface temperature of the toner image can be measured by using a general-purpose non-contact temperature sensor such as a thermocouple type or a thermistor type. Such a temperature sensor may be provided between the heating unit 30 and the first irradiation unit 40a, for example. More specifically, the surface temperature of the toner image can be measured by the method described in Examples.

Examples of the device constituting the irradiation unit 40 include a light emitting diode (LED), a laser light source, and the like.

The first irradiation unit (first light irradiation means) 40a melts the photophase transition compound contained in the developer, and is in the range of 300 nm or more and less than 400 nm, preferably in the range of 330 nm or more and less than 390 nm. Irradiate ultraviolet light with a wavelength. Dose of ultraviolet light in the first illumination portion 40a is preferably in the range of 0.1~200J / cm ^2, more preferably in the range of 0.5~100J / cm ^2, more preferably, 1.0 It is within the range of 50 J / cm ^2.

The second irradiation unit (second light irradiation means) 40b coagulates the photophase transition compound and has visible light having a wavelength in the range of 400 nm or more and 800 nm or less, preferably 450 nm or more and 650 nm or less. Irradiate. The irradiation amount of visible light in the second irradiation unit 40b is preferably 0.1 to 200 J / cm ² , more preferably 0.5 to 100 J / cm ² , and even more preferably 1.0 to 50 J / cm ² . ..

The first irradiation unit 40a and the second irradiation unit 40b irradiate light toward the first surface on the photoconductor side of the recording paper S that holds the toner image, and are nipped into the photoconductor 1 and the transfer roller 50. It is arranged on the photoconductor side with respect to the S surface of the recording paper. Further, the first irradiation unit 40a and the second irradiation unit 40b are arranged in this order along the transport direction (paper transport direction) of the recording paper S.

The first irradiation unit 40a is arranged on the downstream side in the paper transport direction with respect to the nip position of the photoconductor 1 and the transfer roller 40, and on the upstream side in the paper transport direction with respect to the crimping portion 9.

The second irradiation unit 40b is installed on the downstream side in the paper transport direction with respect to the first irradiation unit 40a and on the upstream side in the paper transport direction with respect to the paper discharge unit 14. The second irradiation portion 40b can be installed between the crimping portion 9 and the paper ejection portion 14 in the paper transport direction.

According to the image forming method according to the embodiment of the present invention, the photoconductor 1 is charged with a uniform potential by the charger 2, and then exposed to light flux irradiated by the exposure device 3 based on the original image data. Scan on the body 1 to form an electrostatic latent image. Next, the developing unit 4 supplies a developing agent containing a compound that undergoes a phase transition by 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 supported on the surface of the photoconductor 1 reaches the position of the transfer member 50 by the rotation of the photoconductor 1, the transfer member 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 member 50 also serves as a pressurizing member, and while transferring the toner image from the photoconductor 1 to the recording paper S, the photophase transition compound contained in the toner image can be reliably adhered to the recording paper S. it can.

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 the process in which the recording paper S on which the toner image is transferred is conveyed to the crimping portion 9 by the conveying belt 13, the first irradiation unit 40a has a wavelength of 300 nm or more and less than 400 nm with respect to the toner image transferred on the recording paper S. Irradiate with ultraviolet light having a wavelength. By irradiating the toner image on the first surface of the recording paper S with ultraviolet light by the first irradiation unit 40a, the toner image can be more reliably melted, and the fixing property of the toner image to the recording paper S can be improved. Can be improved.

When the recording paper S on which the toner image is held reaches the crimping portion 9 by the transport belt 13, the pressurizing members (pressurizing means) 91 and 92 crimp the toner image to the first surface of the recording paper S. Since the toner image is softened by the ultraviolet light irradiation by the first irradiation unit 40a before the fixing treatment is performed by the crimping portion 9, energy saving of image crimping on the recording paper S can be achieved.

The pressurizing member (pressurizing means) 91 is preferably in the shape of a roller. Further, the pressurizing member (pressurizing means) 91 can heat the toner image on the recording sheet S when the recording sheet S passes between the pressurizing members 91 and 92. The toner image softened by light irradiation is further softened by this heating, and as a result, the fixability of the toner image on the recording paper S is further improved. The temperature of the pressurizing member 91 when heating is preferably 30 ° C. or higher and 100 ° C. or lower, and preferably 40 ° C. or higher and 100 ° C. or lower.

The recording paper S that has passed between the pressurizing members 91 and 92 irradiates the toner image on the recording paper S with visible light having a wavelength of 400 nm or more and 800 nm or less by the time it reaches the paper ejection portion 14. A second irradiation unit 40b is provided. By irradiating visible light from the second irradiation unit 40b, the toner image on the recording paper S can be more reliably solidified, and the fixability of the toner image to the recording paper S can be further improved.

When forming an image on both sides of the recording paper S, the crimped recording paper S is conveyed to the paper reversing section 24 in front of the paper ejection section 14 and ejected by inverting the front and back sides, or the front and back surfaces are inverted. The recording paper S is conveyed to the image forming unit 10 again.

By using the image forming apparatus as described above, the softening rate of the toner containing the photophase transition compound and the fixability of the image can be improved.

Therefore, the image forming method according to a preferred embodiment of the present invention uses toner containing a compound that undergoes a phase transition from a solid to a liquid by absorbing light having a wavelength of 300 nm or more and less than 400 nm, and a binder resin. The method is a heating step of heating a toner image formed on a recording medium, and a first light of irradiating the toner image heated by the heating step with light having a wavelength of 300 nm or more and less than 400 nm. The fixing step includes a fixing step of fixing the toner image irradiated with light by the first light irradiation step to the recording medium, and the fixing step pressurizes the toner image to the recording medium. It includes a pressurizing step of crimping, and a second light irradiation step of irradiating the toner image crimped to the recording medium by the pressurizing step with light having a wavelength of 400 nm or more and 800 nm or less.

Next, the photophase transition compound and the binder resin essential to the toner used in the image forming apparatus of the present invention, and other components optionally contained will be described.

[Photophase transition compound]
The photophase transition compound used in the present invention undergoes a phase transition from a solid to a liquid by absorbing light having a wavelength of 300 nm or more and less than 400 nm. The type is not particularly limited, but an azobenzene derivative is preferable from the viewpoint of softening rate.

<Azobenzene derivative>
The azobenzene derivative according to the present invention is preferably a compound represented by the following chemical formulas (1) to (4).

(In the above chemical formula (1), R is an alkyl group or an alkoxy group having the same 6 to 16 carbon atoms.)

(In the above chemical formula (2), R is a functional group represented by the following chemical formula (5) independently, and n is an integer of 1 to 4.)

(In the above chemical formula (3), R is an independent functional group represented by the following chemical formula (5), and n is an integer of 1 to 4 independently.)

(In the above chemical formula (5), m is an integer of 0 to 16, and l is an integer of 1 to 16.)

(In the above chemical formula (4), R ₁ , R ₂ and R ₃ are independently hydrogen atom, alkyl group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, alkanoyl group, alkanoyloxy group and alkoxyphenyl. Selected from the group consisting of groups and N-alkylaminocarbonyl groups, n represents an integer, except when all of _{R 1} , R ₂ and R _{3 are hydrogen atoms.)}
<< Compound represented by chemical formula (1) >>
As the azobenzene derivative, the compound represented by the above chemical formula (1) is preferably used.

In the chemical formula (1), R is an alkyl group or an alkoxy group having the same 6 to 16 carbon atoms. When the number of carbon atoms of the alkyl group or alkoxy group used in R is in such a range, a photophase transition is likely to occur and the softening rate by light irradiation is increased. Moreover, the synthesis of an azobenzene derivative is easy. The alkyl group or alkoxy group used in R preferably has 6 to 12 carbon atoms. When the number of carbon atoms is 6 to 12, the melting point of the azobenzene derivative is lowered, the softening rate of the toner by light irradiation is increased, and the fixability of the image is further improved.

Examples of alkyl groups having 6 to 16 carbon atoms used in R include n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group and n-dodecyl. Linear alkyl groups such as groups, n-tridecyl groups, n-tetradecyl groups, n-pentadecyl groups, n-hexadecyl groups; 1-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethyl Butyl group, 2-ethylbutyl group, 1-methylhexyl group, t-octyl group, 1-methylheptyl group, 2-ethylhexyl group, 2-propylpentyl group, 2,2-dimethylheptyl group, 2,6-dimethyl- Branched alkyl groups such as 4-heptyl group, 3,5,5-trimethylhexyl group, 1-methyldecyl group, 1-hexylheptyl group; can be mentioned.

Examples of the alkoxy groups having 6 to 16 carbon atoms used in R include n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, and n-undecyloxy group. Linear alkoxy groups such as group, n-dodecyloxy group, n-tridecyloxy group, n-tetradecyloxy group, n-pentadecyloxy group, n-hexadecyloxy group: 1-methylpentyloxy group. , 4-Methyl-2-pentyloxy group, 3,3-dimethylbutyloxy group, 2-ethylbutyloxy group, 1-methylhexyloxy group, t-octyloxy group, 1-methylheptyloxy group, 2-ethylhexyl Oxy group, 2-propylpentyloxy group, 2,2-dimethylheptyloxy group, 2,6-dimethyl-4-heptyloxy group, 3,5,5-trimethylhexyloxy group, 1-methyldecyloxy group, 1 − Branched alkoxy groups such as hexylheptyloxy groups;

More specific examples of the azobenzene derivative represented by the chemical formula (1) are 4,4'-dihexylazobenzene, 4,4'-dioctylazobenzene, 4,4'-didecylazobenzene, and 4,4'-didodecyl. Azobenzene, 4,4'-dihexadecylazobenzene, 4,4'-bis (hexyloxy) azobenzene, 4,4'-bis (octyloxy) azobenzene, 4,4'-bis (dodecyloxy) azobenzene, 4, There are 4'-bis (hexadecyloxy) azobenzene and the like.

As described above, the alkyl group or alkoxy group having 6 to 16 carbon atoms used in R may be linear or branched. However, a linear alkyl group or an alkoxy group is preferable from the viewpoint of forming a rod-shaped molecule in which a photophase transition is likely to occur.

The method for synthesizing the azobenzene derivative represented by the chemical formula (1) is not particularly limited, and a conventionally known synthesis method can be applied. For example, in the case of an azobenzene derivative in which R in the chemical formula (1) is an alkyl group, 4,4'-dialkylazobenzene can be obtained by treating p-alkylaniline with manganese dioxide as an oxidizing agent in toluene. (See reaction formula (1) below).

Further, for example, in the case of an azobenzene derivative in which R of the chemical formula (1) is an alkoxy group, if alkyl halide is allowed to act on 4,4'-dihydroxyazobenzene in N, N-dimethylformamide (DMF), 4,4'-Dialkoxyazobenzene can be obtained (see reaction formula (2) below).

<< Compounds represented by chemical formulas (2) to (3) >>
As the azobenzene derivative, a compound having a sugar alcohol ester structure represented by the above chemical formula (2) or a compound having a sugar alcohol ester structure represented by the above chemical formula (3) is also preferably used.

The melting points of the compounds represented by the chemical formulas (2) and (3) are, for example, 50 ° C. or higher, preferably 60 ° C. or higher, for example 140 ° C. or lower, preferably 130 ° C. or lower.

In the above chemical formula (5), m is preferably an integer of 4 to 8, and in the above chemical formula (5), l is preferably an integer of 8 to 12.

Among the compounds represented by the chemical formulas (2) and (3), the compound represented by the chemical formula (2) is preferable, and the compound represented by the following chemical formulas (6) to (8) is more preferable. It is more preferably a compound represented by the following chemical formula (8).

(In the above chemical formula (6), R is a functional group represented by the following chemical formula (9).)

(In the above chemical formula (7), R is a functional group represented by the following chemical formula (9).)

(In the above chemical formula (8), R is a functional group represented by the following chemical formula (9).)

The compounds represented by the above chemical formulas (2) and (3) can be synthesized by a known method. For example, the synthesis methods described in paragraphs "0051" to "0064" of JP-A-2014-191078. Can be mentioned.

<< Compound represented by chemical formula (4) >>
As the azobenzene derivative, the compound represented by the above chemical formula (4) is also preferably used.

In the above chemical formula (4), R ₁ is preferably an alkoxy group, more preferably an alkoxy group having 1 to 20 carbon atoms, and further preferably an alkoxy group having 8 to 16 carbon atoms. Further, in the above chemical formula (4), R ₂ and R ₃ are preferably hydrogen atoms. Further, in the above chemical formula (4), n is, for example, an integer of 1 to 8, preferably an integer of 1 to 4.

The melting point of the compound represented by the chemical formula (4) is, for example, 50 ° C. or higher, preferably 60 ° C. or higher, for example 140 ° C. or lower, preferably 130 ° C. or lower.

Among the compounds represented by the above chemical formula (4), preferably, the cyclic dimer in which n is 1 in the above chemical formula (4), that is, the cyclic dimer represented by the following chemical formula (10), and , In the above chemical formula (4), it is a cyclic trimer in which n is 2, that is, a cyclic trimer represented by the following chemical formula (11), and more preferably, the cyclic 2 represented by the following chemical formula (10). It is a trimer.

(In the above chemical formula _(10), R 1, _{R 2} and _{R 3} are the same defined as _R 1, _{R 2} and _{R 3} of Formula (4).)

(In the above chemical formula _(11), R 1, _{R 2} and _{R 3} are the same defined as _R 1, _{R 2} and _{R 3} in the general formula (4).)
The compound represented by the chemical formula (4) can be synthesized by a known method, and examples thereof include the synthesis methods described in paragraphs "0072" to "0081" of JP-A-2014-191878.

The azobenzene derivatives represented by the above chemical formulas (1) to (4) may be used alone or in combination of two or more. Among these, the azobenzene derivative represented by the above chemical formula (1) is preferable from the viewpoint that the softening rate is more likely to be improved.

<Bundling resin>
The toner according to the present invention contains a binder resin. As such a 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.

Among these, at least one binder resin is selected from the group consisting of styrene resin, acrylic resin, styrene acrylic resin, and polyester resin from the viewpoint of having low viscosity when melted and having high sharp melt property. It is preferable to contain at least one selected from the group consisting of styrene acrylic resin and polyester resin.

Hereinafter, the styrene acrylic resin and the polyester resin, which are more preferable binding resins, will be described.

(Styrene acrylic resin)
The styrene acrylic resin referred to in the present invention is 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 t-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene and pn-dodecyl styrene.

The (meth) acrylic acid ester monomer is typically the acrylic acid ester monomer and the methacrylate ester monomer shown below, and examples of the acrylic acid ester monomer include methyl acrylate and the like. Examples thereof include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, dodecyl acrylate and phenyl acrylate phenyl. Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate. , Dodecyl 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.

In addition to the above-mentioned copolymers formed only of the styrene monomer and the (meth) acrylic acid ester monomer, the styrene-acrylic copolymer also includes the styrene monomer and the (meth) acrylic acid ester. In addition to the 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 according to the present invention will be illustrated, but the vinyl monomers that can be used in combination are not limited to those shown below.

(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, etc. Vinyl ethyl ketone, vinyl hexyl ketone, etc. (5) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. (6) Other vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylonitrile, methacrylonitrile Acrylic acid such as nitrile and 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, and a phosphoric acid group. 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, and itaconic acid monoalkyl ester. ..

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, a known chain transfer agent such as n-octyl mercaptan 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 of the binder resin and the glass transition temperature are controlled. It is possible to make appropriate adjustments from the viewpoint. 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 or diazo 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, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2, Examples thereof include 4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,5-t-butylperoxycyclohexyl) propane, and tris- (t-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 monomer used and the type of the polymerization initiator, but is preferably 50 to 100 ° C, more preferably 55 to 90 ° C. The polymerization time varies depending on the monomer used and the type of polymerization initiator, but is preferably 2 to 12 hours, for example.

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

(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 acids such as octadecanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids 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 the polyester resin can be produced by 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 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. Titanium compounds 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, and tributylaluminate. 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 content ratio of the photophase transition compound and the binder resin in the toner according to the present invention is preferably in the range of photophase transition compound: binder resin = 5:95 to 80:20 (mass ratio). Within this range, the photophase transition of the photophase transition compound is likely to occur, and the softening rate of the toner becomes sufficient.

The glass transition temperature (Tg) of the toner 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 and heat-resistant storage property.

The glass transition temperature (Tg) of the toner can be controlled by selecting the type of monomer in the binder resin, adjusting the copolymerization ratio (mass ratio) and molecular weight of the monomer, and the like. For example, taking a styrene acrylic resin as an example, the glass transition temperature can be lowered by increasing the copolymerization ratio (mass ratio) of n-butyl acrylate having a low glass transition temperature with respect to the entire monomer. Further, Tg can be increased by increasing the copolymerization ratio (mass ratio) of styrene having a high glass transition temperature. Taking a polyester resin as an example, the glass transition temperature can be controlled by adjusting the types of the dicarboxylic acid monomer and the diol monomer, and the mixing ratio (mass ratio) of these. For example, by copolymerizing a trifunctional or higher functional monomer such as trimellitic acid at an arbitrary polymerization ratio (mass ratio), cross-linking can be generated intramolecularly or between molecules, and the glass transition temperature can be obtained. Can be raised.

The softening point (Tsp) of the toner is preferably 80 to 130 ° C., more preferably 90 to 120 ° C., from the viewpoint of fixability and heat-resistant storage property. The softening point of the toner is controlled by selecting the type of monomer in the binder resin, adjusting the copolymerization ratio (mass ratio) and molecular weight of the monomer, and the like, as in the case of the glass transition temperature. be able to. It can also be controlled by selecting the type of photophase transition compound.

The glass transition temperature and softening point of the toner can be measured by the method described in Examples.

The toner according to the present invention 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.

The toner according to the present invention may contain other components such as a colorant, a mold release agent, a charge control agent, and an external additive in addition to the photophase transition compound and the binder resin. Hereinafter, other components will be described.

<Colorant>
The toner of 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 carbon black includes channel black, furnace black, acetylene black, thermal black, lamp black, and the like. Can be mentioned. Examples of the magnetic material include ferrite and magnetite.

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; 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 0.5 to 20% by mass, more preferably 2 to 10% by mass in the toner.

<Release agent>
The toner according to the present invention may contain a mold release agent. The release agent used is not particularly limited, and various known waxes can be used. Examples of the wax include low molecular weight polypropylene, polyethylene, oxidized low molecular weight polypropylene, polyolefins such as polyethylene, paraffin wax, synthetic ester wax and the like. Above all, it is preferable to use paraffin wax from the viewpoint of improving the storage stability of the toner.

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

<Charge control agent>
The toner according to the present invention may contain a charge control agent. The charge control agent used is not particularly limited as long as it is a substance capable of giving positive or negative charge by triboelectric charge and is colorless, and various known positive charge control agents and negative charge control agents and negative charges are used. A chargeable 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, more preferably in the range of 0.1 to 10% by mass in the toner.

<External agent>
In order to improve the fluidity, chargeability, cleaning property, etc. of the toner, the toner of the present invention is composed by adding an external agent such as a fluidizing agent, a cleaning aid, which is a so-called post-treatment agent, to the toner particles. You may.

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 resistance and storage stability and environmental stability.

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

<Average particle size of toner>
The average particle size of the toner is preferably 4 to 10 μm, more preferably 6 to 9 μm in terms of volume-based median diameter (D50). When the volume-based median diameter (D50) 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.

In the present invention, the toner volume-based median diameter (D50) is a computer system (Beckman Coulter) in which the data processing software "Software V3.51" is mounted on "Coulter Counter 3" (manufactured by Beckman Coulter Co., Ltd.). It is measured and calculated using a measuring device connected to (manufactured by Co., Ltd.).

Specifically, 0.02 g of the measurement sample (toner) is 20 mL of a surfactant solution (for the purpose of dispersing toner particles, for example, a neutral detergent containing a surfactant component diluted 10-fold with pure water). After adding to the solution) and acclimatizing, ultrasonic dispersion was performed for 1 minute to prepare a toner dispersion, and this toner dispersion contained "ISOTONII" (manufactured by Beckman Coulter, Inc.) in the sample stand. Pipette into the beaker until the indicated concentration on the measuring device is 8%.

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 50 μm, 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 diameter (D50).

[Toner manufacturing method]
The method for producing the toner according to the present invention is not particularly limited, but a method using an emulsification / agglutination method in which the particle size and shape can be easily controlled is preferable.

Such a manufacturing method
(1A) Bending resin particle dispersion preparation step for preparing a dispersion of binder resin particles (1B) Photophase transition compound particle dispersion preparation step for preparing a dispersion of photophase transition compound particles (2) Bending resin A flocculant is added to an aqueous medium in which particles, photophase transition compound particles, and colorant particles contained as necessary are mixed, and salting is allowed to proceed at the same time, and aggregated / fused particles are formed. Meeting step to form (3) Aging step to form toner particles by controlling the shape of the meeting particles (4) Filtering and washing to separate toner particles from an aqueous medium and remove surfactants and the like from the toner particles. Step (5) Drying step of drying the washed toner particles (6) It is preferable to include each step of adding an external additive to the dried toner particles. When the toner contains a colorant, it is preferable to perform (1) a colorant particle dispersion preparation step for preparing a dispersion of colorant particles before the associating step. Hereinafter, the steps (1A) to (1C) will be described.

(1A) Bundling Resin Particle Dispersion Solution Preparation Step 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. Or a method in which a crystalline resin is dissolved in a solvent such as ethyl acetate to prepare a solution, the solution is emulsified and dispersed in an aqueous medium using a disperser, and then a solvent removal treatment is performed.

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

(1B) Photophase Transition Compound Particle Dispersion Solution Preparation Step This step is a step of preparing a dispersion liquid of photophase transition compound particles by dispersing the photophase transition compound in the form of fine particles in an aqueous medium. In preparing the photophase transition compound particle dispersion, first, the photophase transition compound emulsion is prepared. Examples of the method for preparing the photophase transition compound emulsion include a method in which the photophase transition compound is dissolved in an organic solvent to obtain a photophase transition compound solution, and then the photophase transition compound solution is emulsified in an aqueous medium. Be done.

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

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

The addition ratio of the photophase transition compound solution is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 30 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the aqueous medium.

Further, the temperatures of the photophase transition compound solution and the aqueous medium at the time of mixing the photophase transition compound solution and the aqueous medium are in the temperature range below the boiling point of the organic solvent, and are preferably 20 ° C. or higher and 80 ° C. Hereinafter, it is more preferably 30 ° C. or higher and 75 ° C. or lower. When the photophase transition compound solution and the aqueous medium are mixed, the temperature of the photophase transition compound solution and the temperature of the aqueous medium may be the same or different from each other, and are preferably the same as each other.

As for the stirring conditions of the disperser, for example, when the capacity is 1 to 3 L, the rotation speed is preferably 7,000 rpm or more and 20,000 rpm or less, and the stirring time is preferably 10 minutes or more and 30 minutes or less.

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

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

The mass average particle size of the photophase transition compound particles in the photophase transition compound particle dispersion is preferably 90 nm or more and 1200 nm or less. The mass average particle size of the photophase transition compound particles is the viscosity when the photophase transition compound is blended in an organic solvent, the blending ratio of the photophase transition compound solution and water, and the dispersion when preparing the photophase transition compound 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 compound particles in the photophase transition compound 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 this step is not particularly limited as long as it can dissolve the photophase transition compound. 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>
Examples of the aqueous medium used in this step include water or an aqueous medium containing 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. Be done. 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 dodecylate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate and the like. Examples of the nonionic surfactant include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl 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.

(1C) Colorant Particle Dispersion Liquid Preparation Step This colorant particle dispersion liquid preparation step 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 10 to 300 nm, more preferably 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.).

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

The coagulant used in (2) the associating 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 metal salts 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, for example, a case where a magnetic substance is contained and used as a one-component magnetic toner, a case where the toner is mixed with a so-called carrier and used as a two-component developer, or a case where a non-magnetic toner is used alone. Any of these 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, 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 the magnetic material powder is dispersed in a binder resin can also be used. 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-dispersed 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 can be used. Can be done.

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 SYMPATEC) 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.

[Image formation method]
Examples of the image forming method to which the image forming apparatus according to the present invention is applied include various known electrophotographic forming methods. For example, it can be used for 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 effects of the present invention will be described with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

The glass transition temperature (Tg) and softening point (Tsp) of the toner were measured by the following methods.

<Glass transition temperature (Tg) of toner>
The glass transition temperature (Tg) was determined using "Diamond DSC" (manufactured by PerkinElmer). As a measurement procedure, 3.0 mg of a sample (toner) was sealed in an aluminum pan and set in a holder. The reference used was an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature rise rate of 10 ° C./min, and a temperature decrease rate of 10 ° C./min, and the temperature was controlled by Heat-cool-Heat. The analysis was performed based on the data in Heat. For the obtained DSC chart, an extension of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rising portion of the first endothermic peak and the peak apex are drawn, and the temperature at the intersection is drawn. Was defined as the glass transition temperature.

<Toner softening point (Tsp)>
The softening point (Tsp) of the toner was measured using a flow tester as shown below. Specifically, first, in an environment of 20 ° C. and 50% RH, 1.1 g of a sample (toner) is placed in a petri dish, flattened, left to stand for 12 hours or more, and then a molding machine "SSP-10A" (stock). A cylindrical molded sample with a diameter of 1 cm was prepared by pressurizing with a force of 3820 kg / cm ^{2 for 30 seconds by Shimadzu Corporation).} Next, this molded sample was subjected to a load of 196 N (20 kgf), a starting temperature of 60 ° C., and a preheating time of 300 seconds by a flow tester "CFT-500D" (manufactured by Shimadzu Corporation) in an environment of 24 ° C. and 50% RH. Under the condition of a heating rate of 6 ° C./min, it is extruded from the hole of the cylindrical die (diameter 1 mm x height 1 mm) using a piston with a diameter of 1 cm from the end of preheating, and the offset value is measured by the melting temperature measurement method of the heating method. _{The offset method temperature Toffset} measured at a setting of 5 mm was defined as the softening point (Tsp) of the toner.

[Synthesis of azobenzene derivatives (photophase transition compounds)]
<Synthesis of compound (Compound 1) in which R in the chemical formula (1) is an n-dodecyl group>
Toluene 10 mL and active manganese dioxide (0.30 g, 3.5 mmol) were added to 4-dodecylaniline (0.26 g, 1.0 mmol), and stirring was continued at 120 ° C. for 8 hours. 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: hexane = 1: 5 (volume ratio) as a developing solvent. Then, the solvent was removed to obtain 4,4'-zidodecylazobenzene (Compound 1).

<Synthesis of compound (Compound 2) in which R in the chemical formula (1) is an n-octyl group>
4,4'-Dioctylazobenzene (Compound 2) in the same manner as in the synthesis of Compound 1 above, except that n-octylaniline (0.21 g, 1.0 mmol) was used instead of 4-dodecylaniline. Got

<Synthesis of compound (Compound 3) in which R in the chemical formula (1) is an n-hexyl group>
4,4'-Dihexylazobenzene (Compound 3) in the same manner as in the synthesis of Compound 1 above, except that n-hexylaniline (0.17 g, 1.0 mmol) was used instead of 4-dodecylaniline. Got

[Preparation of binder resin]
<Preparation of Styrene Acrylic Resin Particle Dispersion Solution 1 Containing Styrene Acrylic Resin 1>
(First stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device is charged with a solution prepared by dissolving 8 parts by mass of sodium dodecyl sulfate in 3000 parts by mass of ion-exchanged water, and stirred at a stirring speed of 230 rpm under a nitrogen stream. While doing so, the internal temperature was raised to 80 ° C. After raising the temperature, a solution prepared by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added, and the liquid temperature was adjusted to 80 ° C. again, 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 0.0 parts by mass and 16.0 parts by mass of n-octyl-3-mercaptopropionate was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours and stirred to carry out polymerization. This was performed to prepare a styrene acrylic resin particle dispersion solution (1A) containing the styrene acrylic resin particles (1a).

(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 7 parts by mass of polyoxyethylene (2) dodecyl ether sodium sulfate in 800 parts by mass of ion-exchanged water was charged, and the temperature was 98 ° C. After heating to, 260 parts by mass of the styrene acrylic resin particle dispersion solution (1A) obtained above, 245 parts by mass of styrene, 120 parts by mass of n-butyl acrylate, 1.5 parts by mass of n-octyl-3-mercaptopropionate. , A mechanical disperser having a circulation path by adding a polymerizable monomer solution in which 67 parts by mass of paraffin wax "HNP-11" (manufactured by Nippon Seiwa Co., Ltd.), which is a release agent, is dissolved at 90 ° C. A dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing with "CREARMIX (registered trademark)" (manufactured by M Technique Co., Ltd.) for 1 hour.

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 82 ° C. for 1 hour to carry out polymerization. A styrene acrylic resin particle dispersion (1B) containing styrene acrylic resin particles (1b) was prepared.

(Third stage polymerization)
A solution prepared by dissolving 11 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water was added to the styrene acrylic resin particle dispersion (1B) obtained above, and then 435 parts by mass of styrene was added under a temperature condition of 82 ° C. A polymerizable monomer solution consisting of 130 parts by mass of n-butyl acrylate, 33 parts by mass of methacrylic acid and 8 parts by mass of n-octyl-3-mercaptopropionate 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 1 containing a styrene acrylic resin 1. The glass transition temperature (Tg) of the styrene acrylic resin 1 was measured and found to be 45 ° C.

<Preparation of Styrene Acrylic Resin Particle Dispersion 2 Containing Styrene Acrylic Resin 2>
(First stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device is charged with a solution prepared by dissolving 8 parts by mass of sodium dodecyl sulfate in 3000 parts by mass of ion-exchanged water, and stirred at a stirring speed of 230 rpm under a nitrogen stream. While doing so, the internal temperature was raised to 80 ° C. After raising the temperature, a solution prepared by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added, and the liquid temperature was adjusted to 80 ° C. again, 550 parts by mass of styrene, 180 parts by mass of n-butyl acrylate, 68 parts of methacrylic acid. A polymerizable monomer solution consisting of 0.0 parts by mass and 16.0 parts by mass of n-octyl-3-mercaptopropionate was added dropwise over 1 hour, and then heated at 80 ° C. for 2 hours and stirred to carry out polymerization. This was performed to prepare a styrene acrylic resin particle dispersion solution (2A) containing the styrene acrylic resin particles (2a).

(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 7 parts by mass of polyoxyethylene (2) dodecyl ether sodium sulfate in 800 parts by mass of ion-exchanged water was charged, and the temperature was 98 ° C. After heating to, 260 parts by mass of the styrene acrylic resin particle dispersion solution (2A) obtained above, 285 parts by mass of styrene, 80 parts by mass of n-butyl acrylate, 1.5 parts by mass of n-octyl-3-mercaptopropionate. , And a polymerizable monomer solution prepared by dissolving 67 parts by mass of paraffin wax "HNP-11" (manufactured by Nippon Seiwa Co., Ltd.), which is a release agent, at 90 ° C., and mechanically dispersed with a circulation path. A dispersion containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour with a machine "CREARMIX (registered trademark)" (manufactured by M Technique Co., Ltd.).

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 82 ° 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 11 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water was added to the styrene acrylic resin particle dispersion (2B) obtained above, and 485 parts by mass of styrene was added under a temperature condition of 82 ° C. A polymerizable monomer solution consisting of 80 parts by mass of n-butyl acrylate, 33 parts by mass of methacrylic acid, and 8 parts by mass of n-octyl-3-mercaptopropionate 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 2 containing a styrene acrylic resin 2. The glass transition temperature (Tg) of the styrene acrylic resin 2 was measured and found to be 54 ° C.

<Preparation of polyester resin particle dispersion liquid 1 containing polyester resin 1>
In a 10 liter capacity four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer, and thermocouple, 524 parts by mass of bisphenol A propylene oxide 2 mol addition, 105 parts by mass of terephthalic acid, 69 parts by mass of fumaric acid, And 2 parts by mass of tin octylate (esterification catalyst) was added, and a polycondensation reaction was carried out at a temperature of 230 ° C. for 8 hours. Further, after continuing the polycondensation reaction at 8 kPa for 1 hour, the mixture was cooled to 160 ° C. to obtain a polyester resin 1. 100 parts by mass of polyester resin 1 is crushed with "Randelmill type: RM" (manufactured by Tokuju Kosakusho Co., Ltd.), mixed with 638 parts by mass of a 0.26% by mass sodium dodecyl sulfate aqueous solution prepared in advance, and super-used with stirring. Using a sonic homogenizer "US-150T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.), ultrasonic dispersion was performed with V-LEVEL at 300 μA for 30 minutes to obtain a polyester resin particle dispersion liquid 1. Moreover, when the glass transition temperature (Tg) of the polyester resin 1 was measured, it was 42 ° C.

[Making toner]
<Manufacturing of toner 1>
(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.)". The particle size of carbon black in the dispersion was 160 nm in terms of median diameter on a number basis.

(Preparation of azobenzene derivative particle dispersion 1)
80 parts by mass of dichloromethane and 20 parts by mass of compound 1 were mixed and stirred while heating at 50 ° C. to obtain a solution containing compound 1. To 100 parts by mass of the obtained 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 azobenzene derivative emulsion 1.

The obtained azobenzene derivative emulsion 1 was put into a separable flask, and the organic solvent was removed by heating and stirring at 40 ° C. for 90 minutes while sending nitrogen into the gas phase to obtain the azobenzene derivative particle dispersion liquid 1. It was.

(Agglomeration / fusion)
The styrene acrylic resin particle dispersion 1 prepared above is 504 parts by mass in terms of solid content, the azobenzene derivative particle dispersion 1 is 216 parts by mass in terms of solid content, 900 parts by mass of ion-exchanged water, and the carbon black dispersion is solid content. In terms of conversion, 70 parts by mass was charged into a reaction device equipped with a stirrer, a temperature sensor, and 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.

Next, an aqueous solution prepared by dissolving 2 parts by mass of magnesium chloride hexahydrate in 1000 parts by mass of ion-exchanged water was added dropwise over 10 minutes with stirring, and then the temperature was raised, and this system was heated over 60 minutes to 70. 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, 190 parts by mass of sodium chloride. Was added to 760 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 particles were fused by heating and stirring at 75 ° C. Then, the mixture was cooled to 30 ° C. to obtain a dispersion of toner particles.

The dispersion of toner particles obtained above was solid-liquid separated by a centrifuge to form a wet cake of toner particles. The wet cake is washed with ion-exchanged water at 35 ° C. in the centrifuge until the electrical conductivity of the filtrate reaches 5 μS / cm, and then transferred to a “flash jet dryer (manufactured by Seishin Enterprise Co., Ltd.)” to obtain a water content. Was dried to 0.5% by mass to prepare toner 1. The volume-based median diameter (D50) of the obtained toner 1 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 7.2 μm. The glass transition temperature (Tg) of the toner 1 was 45 ° C., and the softening point (Tsp) was 98 ° C.

<Preparation of toner 2>
Toner 2 was produced in the same manner as in <Preparation of Toner 1> except that the styrene acrylic resin particle dispersion liquid 2 was used instead of the styrene acrylic resin particle dispersion liquid 1. The volume-based median diameter (D50) of the obtained toner 2 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 7.0 μm. The glass transition temperature (Tg) of the toner 2 was 54 ° C., and the softening point (Tsp) was 110 ° C.

<Preparation of toner 3>
The toner 3 was prepared in the same manner as in <Preparation of Toner 1> except that the polyester resin particle dispersion 1 was used instead of the styrene acrylic resin particle dispersion 1. The volume-based median diameter (D50) of the obtained toner 3 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 7.4 μm. The glass transition temperature (Tg) of the toner 3 was 42 ° C., and the softening point (Tsp) was 93 ° C.

<Preparation of toner 4>
Toner 4 was prepared in the same manner as in <Preparation of Toner 1> except that the azobenzene derivative particle dispersion 2 prepared as described below was used instead of the azobenzene derivative particle dispersion 1. The volume-based median diameter (D50) of the obtained toner 4 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 6.9 μm. The glass transition temperature (Tg) of the toner 4 was 45 ° C., and the softening point (Tsp) was 94 ° C.

(Preparation of azobenzene derivative particle dispersion 2)
80 parts by mass of dichloromethane and 20 parts by mass of compound 2 were mixed and stirred while heating at 50 ° C. to obtain a solution containing compound 2. To 100 parts by mass of the obtained 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 azobenzene derivative emulsion 2.

The obtained azobenzene derivative emulsion 2 was put into a separable flask, and the organic solvent was removed by heating and stirring at 40 ° C. for 90 minutes while sending nitrogen into the gas phase to obtain an azobenzene derivative particle dispersion liquid 2. It was.

<Preparation of toner 5>
Toner 5 was prepared in the same manner as in <Preparation of Toner 1> except that the azobenzene derivative particle dispersion 3 prepared as described below was used instead of the azobenzene derivative particle dispersion 1. The volume-based median diameter (D50) of the obtained toner 5 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 6.8 μm. The glass transition temperature (Tg) of the toner 5 was 45 ° C., and the softening point (Tsp) was 91 ° C.

(Preparation of azobenzene derivative particle dispersion 3)
80 parts by mass of dichloromethane and 20 parts by mass of compound 3 were mixed and stirred while heating at 50 ° C. to obtain a solution containing compound 3. To 100 parts by mass of the obtained 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 azobenzene derivative emulsion 3.

The obtained azobenzene derivative emulsion 3 was put into a separable flask, and the organic solvent was removed by heating and stirring at 40 ° C. for 90 minutes while sending nitrogen into the gas phase to obtain an azobenzene derivative particle dispersion liquid 3. It was.

<Preparation of toner 6>
Toner 6 was prepared in the same manner as in <Preparation of Toner 1> except that the azobenzene derivative particle dispersion 4 prepared as described below was used instead of the azobenzene derivative particle dispersion 1. The volume-based median diameter (D50) of the obtained toner 6 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 7.3 μm. The glass transition temperature (Tg) of the toner 6 was 45 ° C., and the softening point (Tsp) was 112 ° C.

(Preparation of Azobenzene Derivative Particle Dispersion Solution 4)
Compound 4 (see the chemical formula below) is contained in the same manner as in "(1-1) Preparation of UV softening material suspension A" described in paragraphs "0217" to "0227" of JP-A-2014-191078. The photophase transition compound particle dispersion 3 was prepared.

<Manufacturing of toner 7>
Toner 7 was prepared in the same manner as in <Preparation of Toner 1> except that the azobenzene derivative particle dispersion 5 prepared as described below was used instead of the azobenzene derivative particle dispersion 1. The volume-based median diameter (D50) of the obtained toner 7 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 7.0 μm. The glass transition temperature (Tg) of the obtained toner 7 was 45 ° C., and the softening point (Tsp) was 103 ° C.

(Preparation of azobenzene derivative particle dispersion 5)
Compound 5 (see the chemical formula below) is contained in the same manner as in "(1-2) Preparation of UV softening material suspension B" described in paragraphs "0227" to "0238" of JP-A-2014-191078. The photophase transition compound particle dispersion 5 was obtained.

<Preparation of toner 8>
The toner 8 was prepared in the same manner as in <Preparation of Toner 6> except that the polyester resin particle dispersion 1 was used instead of the styrene acrylic resin particle dispersion 1. The volume-based median diameter (D50) of the obtained toner 8 was measured using "Coulter Counter 3 (manufactured by Beckman Coulter Co., Ltd.)" and found to be 7.2 μm. The glass transition temperature (Tg) of the obtained toner 8 was 42 ° C., and the softening point (Tsp) was 109 ° C.

[Preparation of developer]
9.5 g of iron powder having a volume-based median diameter of 70 μm and No. 0.5 g of the toners 1 to 8 was placed in a 20 ml glass container and shaken 200 times per minute with a swing angle of 45 degrees and an arm of 50 cm for 20 minutes to prepare a developer.

[Evaluation: Fixability test]
The fixability test was carried out in a normal temperature and humidity environment (temperature 20 ° C., relative humidity 50% RH) using the developer obtained above. The developer is placed between a pair of parallel flat plate (aluminum) electrodes on which a developer is placed on one side and plain paper (basis weight: 64 g / m ² ) is placed on the other side while sliding by magnetic force, and the gap between the electrodes is 0. The toner was developed under the condition that the toner adhesion amount was 3 g / m ² for 5 mm, DC bias and AC bias, a toner layer was formed on the surface of the paper, and the printed matter fixed by each fixing device was used. An image of 1 cm square of this printed matter was rubbed 10 times with a pressure of 50 kPa with "JK Wiper (registered trademark)" (manufactured by Nippon Paper Crecia Co., Ltd.), and evaluated by the fixing rate of the image. A retention rate of 50% or more was considered acceptable. The image fixation rate is the reflection density of a solid image after rubbing by measuring the density of the image after printing and the image after rubbing with a reflection densitometer "RD-918" (manufactured by Sakata Inks Engineering Co., Ltd.). Is divided by the reflection density of the solid image after printing, and is expressed as a percentage.

As the fixing device, the following two types of devices configured by appropriately modifying the device shown in FIG. 2 were used:
No. 1: There is a heating part 30 and a crimping part 9 in FIG. 2, the wavelength of ultraviolet light emitted from the first irradiation part 40a is 365 nm (light source: LED light source having an emission wavelength of 365 nm ± 10 nm), and the irradiation amount is 3J. / Cm ² . The wavelength of visible light emitted from the second irradiation unit 40b is 505 nm (light source: LED light source having an emission wavelength of 505 nm ± 10 nm), and the irradiation amount is 20 J / cm ² . An infrared heater was used as the heating unit 30, and the temperature was adjusted to be the “toner surface temperature after heating” shown in Table 1 below. The temperature of the pressurizing member 91 was 20 ° C.;
No. 2: There is a heating part 30 and a crimping part 9 in FIG. 2, and the light source and the irradiation amount of the first irradiation part and the second irradiation part are No. Same as 1. An infrared heater was used as the heating unit 30, and the temperature was adjusted to be the “toner surface temperature after heating” shown in Table 1 below. The temperature of the pressurizing member 91 was 80 ° C.

The "toner image surface temperature after heating" is the surface temperature of the toner image after being heated by the heating unit 30, and specifically, it is an installation type between the heating unit 30 and the first irradiation unit 40a. A non-contact thermometer "THERMO-HUNTER (registered trademark) CS-30TAC" (manufactured by OPTEX Co., Ltd.) was installed and measured.

(Examples 1 to 13, Comparative Examples 1 to 2)
As shown in Table 1 below, the above fixability test was performed by changing the type of toner and the conditions of the fixing device in various ways. The configuration of each toner, the conditions of the fixing device, and the evaluation results are shown in Table 1 below. In Comparative Examples 1 and 2, heating was not performed before irradiation with ultraviolet rays.

As is clear from Table 1 above, in the examples, the toner showed high fixability. On the other hand, in the comparative example, the fixability of the toner was low. Since the ultraviolet light source and the ultraviolet irradiation conditions used in the fixability test are constant throughout the examples and comparative examples, the toners of the examples have a faster softening rate than the toners of the comparative examples, and have fixability. Can be said to have improved.

Comparing the fixing devices, No. 1 in which the temperature of the pressurizing member 91 is high. It is better to use the fixing device of No. 2. It can be said that the fixing property tends to be improved as compared with the case where the fixing device of 1 is used.

1 Photoreceptor,
2 Charger,
3 exposed device,
4 developing unit,
5 Transfer section,
6 Static elimination unit 7 Paper transport system,
8 Cleaning department,
9 Crimping part,
10 Image forming part,
11 Paper feed section,
12 Conveyor roller,
13 Conveyance belt,
14 Paper output section,
15 Manual paper feed section,
16 trays,
17 Thermo-hygrometer,
20 Image processing unit,
24 Paper reversing part,
30 Heating part (heating means),
40 Irradiated part,
40a First irradiation unit (first light irradiation means),
40b Second irradiation unit (second light irradiation means),
50 transfer roller,
71 Image reader,
72 Automatic document feeder,
85 blades,
90 Control unit,
91, 92 Pressurizing member (pressurizing means),
100 image forming device,
d Manuscript,
S Recording paper.

Claims (7)

An image forming apparatus using a toner containing a compound and a binder resin that undergoes a phase transition from a solid to a liquid by absorbing light having a wavelength of 300 nm or more and less than 400 nm.
A heating means for heating the toner image formed on the recording medium, and
A first light irradiating means for irradiating the toner image heated by the heating means with light having a wavelength of 300 nm or more and less than 400 nm.
A pressurizing means that pressurizes the toner image irradiated with light by the first light irradiating means and presses the toner image onto the recording medium.
A second light irradiating means for irradiating the toner image pressure-bonded to the recording medium by the pressurizing means with light having a wavelength of 400 nm or more and 800 nm or less.
An image forming apparatus. The image forming apparatus according to claim 1, wherein the heating means heats the surface of the toner image to a temperature equal to or higher than the glass transition temperature of the toner. The image forming apparatus according to claim 2, wherein the heating means heats the surface of the toner image to a temperature lower than the softening point of the toner. The image forming apparatus according to any one of claims 1 to 3, wherein the temperature of the pressurizing means is 30 ° C. or higher and 100 ° C. or lower. The image forming apparatus according to any one of claims 1 to 4, wherein the compound that undergoes a phase transition is an azobenzene derivative. The image forming apparatus according to any one of claims 1 to 5, wherein the binding resin contains at least one selected from the group consisting of a styrene acrylic resin and a polyester resin. An image forming method using a toner containing a compound that undergoes a phase transition from a solid to a liquid by absorbing light having a wavelength of 300 nm or more and less than 400 nm, and a binder resin.
A heating process that heats the toner image formed on the recording medium,
A first light irradiation step of irradiating the toner image heated by the heating step with light having a wavelength of 300 nm or more and less than 400 nm.
A fixing step of fixing the toner image irradiated with light by the first light irradiation step to the recording medium, and a fixing step of fixing the toner image to the recording medium.
Including
The fixing step has a pressurizing step of pressurizing the toner image and pressing it against the recording medium, and a wavelength of 400 nm or more and 800 nm or less with respect to the toner image crimped to the recording medium by the pressurizing step. The second light irradiation step of irradiating light and
An image forming method including.