JP6561641B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method. More specifically, the present invention relates to an image forming method capable of fixing at a low temperature while using a toner having high heat-resistant storage property.

  2. Description of the Related Art In recent years, in electrophotographic image forming apparatuses, there has been a growing need for higher printing speed, higher image quality, and energy saving. Accordingly, electrostatic charge developing toner (hereinafter also simply referred to as “toner”) is used. There is a need for further improvements in heat resistance, crush resistance, durability, and low-temperature fixability.

In the electrophotographic method, the use of energy mainly in a fixing process for fusing and fixing toner developed and transferred onto a medium by heat and pressure is increasing.
In order to reduce the use of energy in the fixing process, a technique of adding a crystalline resin that lowers the thermal characteristics of the toner or sharply melts by heat is widely used (see, for example, Patent Document 1 and Patent Document 2). ).

However, these techniques improve the fixability by heat application, and a system that does not rely only on heat application is required for further low-temperature fixing.
In addition, if the thermal characteristics of the toner are lowered or a crystalline resin is added for low-temperature fixing, it naturally becomes easy to dissolve against heat, while the heat generated by the developing machine in the apparatus causes the toner to melt. There is a problem that fusion (blocking) between toners and heat-resistant storage stability of the toner are lowered.

Here, according to Patent Document 3, etc., it is reported that some compounds having an azobenzene skeleton undergo a photoisomerization reaction when irradiated with light, and the state changes from a solid to a liquid. Yes. Moreover, it has been reported that these compounds undergo a state change from a liquid to a solid by irradiation with visible light or heat.
That is, these compounds are compounds that exhibit a reversible phase transition reaction in which the melting point decreases upon irradiation with light, and the melting point increases upon solidification due to irradiation with visible light or heat. Therefore, it has been reported that such a compound can be contained in a toner and fixed by light energy (for example, see Patent Document 4).
However, when the present compound is contained in the toner, the chargeability of the toner deteriorates and defects such as image fogging occur.

Furthermore, in recent years, in order to suppress the thermal energy to be used, a technical study of a method of fixing toner onto a medium using a fixing solution has been made (for example, see Patent Document 5).
This system supplies a foam-like fixer onto the toner layer and plasticizes the toner resin, thereby lowering the temperature at which the toner softens and reducing the amount of heat required for fixing. It is expected as a technology.
However, since a liquid is supplied as a fixing solution, image sticking due to stickiness of the image after fixing has become a problem.

JP 2012-163606 A JP 2008-191260 A International Publication No. 2013/081155 JP 2014-191078 A JP 2007-219105 A

  The present invention has been made in view of the above problems and circumstances, and a problem to be solved is to provide an image forming method capable of fixing at a low temperature while using a toner having high heat-resistant storage property.

In order to solve the above-mentioned problems, the present inventor, in the process of examining the cause of the above-described problem, a compound that is solid before irradiation with light and has a melting point lowered by light irradiation and becomes a liquid is displayed on the image at the time of fixing. It has been found that an image forming method capable of fixing at a low temperature can be provided by using a toner having high heat-resistant storage stability by melting the compound immediately before or simultaneously with the fixing step.
That is, the said subject which concerns on this invention is solved by the following means.

1. Developing a toner image by developing the electrostatic latent image formed on the photoreceptor with toner, transferring the toner image to a recording medium, and irradiating the toner image on the recording medium with light An image forming method comprising: irradiating light that lowers the melting point of the compound in the presence of the compound that lowers the melting point by the step of fixing a toner image on the recording medium ,
An image forming method comprising separately forming the toner image and supplying the compound .

2. The image forming method according to claim 1, wherein the supply of pre hear compound is a before forming the toner image.

3. The image forming method according to paragraph 1 the supply of pre hear compounds, characterized in that is later formation of the toner image.
4). The image forming method according to any one of Items 1 to 3, wherein the compound is present on the toner image in the step of irradiating light.
5. The image forming method according to any one of Items 1 to 4, wherein the compound is supplied as particles.
6). The image forming method according to any one of Items 1 to 4, wherein the compound is supplied by coating the compound.
7). Item 7. The image forming method according to any one of Items 1 to 6, wherein the compound is a photoisomerizable compound.
8). Item 8. The image forming method according to any one of Items 1 to 7, wherein the light applied to the compound is ultraviolet light.

9 . The image forming method according to any one of Items 1 to 8 , further comprising a step of irradiating visible light after the fixing step.

10 . The image forming method according to any one of Items 1 to 9 , further comprising a step of heating at a temperature lower than a first glass transition point of the toner after the fixing step.

11 . The image forming method according to any one of Items 1 to 10, wherein the toner has a first glass transition point of 45 ° C. or higher.

By the above means of the present invention, it is possible to provide an image forming method capable of fixing at a low temperature while using a toner having a high heat-resistant storage property.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The present inventor supplies a compound that changes from a solid to a liquid by irradiating light after the toner image formation, that is, it is solid before irradiating light, and the melting point is lowered by the light irradiation and becomes a liquid. The presence of the compound on the image at the time of fixing is presumed that the toner is plasticized and can be fixed at a low temperature.
In addition, since these compounds change from a liquid to a solid upon irradiation with heat or visible light, image sticking after fixing does not occur.

  Furthermore, the first glass transition point (hereinafter also simply referred to as “Tg”) of the toner used for image formation can be set as high as before. For this reason, it is presumed that a toner having high resistance to stress in the developing unit and high heat storage stability could be provided. It should be noted that the toner used in the image forming method of the present invention is not significantly different from the toner used so far as long as stress resistance and heat storage stability are ensured. No deterioration such as image fogging occurs.

Schematic sectional view showing an example of an image forming apparatus employing the image forming method of the present invention Schematic sectional view showing a single fixing device employing the image forming method of the present invention.

The image forming method of the present invention includes a step of developing an electrostatic latent image formed on a photoreceptor with toner to form a toner image, a step of transferring the toner image to a recording medium, and a step on the recording medium. An image forming method comprising: irradiating a toner image with light that lowers the melting point of the compound in the presence of a compound whose melting point is lowered by light irradiation; and fixing the toner image on the recording medium. The toner image formation and the compound supply are performed separately . This feature is a technical feature common to the inventions according to claims 1 to 11 .

  In the present invention, the step of supplying the compound whose melting point is lowered by the light irradiation may be before the step of forming the toner image, or the step of supplying the compound whose melting point is lowered by the light irradiation. It may be after the step of forming the toner image, but in the step of irradiating light, a compound whose melting point is lowered by light irradiation is disposed on the toner image so as not to be blocked by the toner. It is preferable. As a result, in the step of irradiating light, the compound is irradiated with light without being blocked by the toner. As a result, the compound can be effectively melted, and thus fixing at a lower temperature becomes possible. preferable.

  In the present invention, it is preferable to have a step of irradiating visible light after the fixing step, because the melted compound quickly solidifies, and as a result, image sticking can be suppressed.

  In the present invention, the step of heating at a temperature lower than the first glass transition point of the toner after the fixing step causes the melted compound according to the present invention to solidify quickly and be used for image formation. This is preferable because the toner does not become soft and as a result, image sticking can be suppressed.

  In the present invention, it is preferable that the first glass transition point of the toner is 45 ° C. or higher because the heat-resistant storage property is further improved.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

≪Outline of image forming method≫
The image forming method of the present invention includes a step of developing an electrostatic latent image formed on a photoreceptor with toner to form a toner image, a step of transferring the toner image to a recording medium, and a step on the recording medium. An image forming method comprising: irradiating a toner image with light that lowers the melting point of the compound in the presence of a compound whose melting point is lowered by light irradiation; and fixing the toner image on the recording medium. The toner image formation and the compound supply are performed separately .

[Step of forming toner image]
In this step, the electrostatic latent image formed on the photoconductor is developed with toner to form a toner image.
The photoreceptor is not particularly limited, and examples thereof include organic photoreceptors and inorganic photoreceptors such as amorphous silicon and selenium.
The electrostatic latent image is formed by, for example, charging the surface of the electrostatic latent image carrier uniformly with a charging unit and exposing the surface of the electrostatic latent image carrier imagewise with an exposure unit. Is called.
The charging unit and the exposure unit are not particularly limited, and those generally used in an electrophotographic image forming method can be used.

<Development>
By development, the electrostatic latent image is developed with a dry developer containing toner containing a binder resin to form a toner image.
The toner image is formed using a dry developer containing a toner containing a binder resin, for example, using a developing unit including a stirrer that frictionally stirs and charges the toner and a rotatable magnet roller. Is called.
Specifically, in the developing unit, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and is held on the surface of the rotating magnet roller, thereby forming a magnetic brush. Since the magnet roller is arranged in the vicinity of the electrostatic latent image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is part of the electrostatic latent image carrier by the electric attractive force. Move to the surface. As a result, the electrostatic latent image is developed with toner, and a toner image is formed on the surface of the electrostatic latent image carrier.

[Step of transferring toner image to recording medium]
In this step, the toner image is transferred to a recording medium (hereinafter, this step is also simply referred to as “transfer step”).
Transfer of the toner image to the recording medium is performed by peeling and charging the toner image onto the recording medium.
As the transfer means, for example, a corona transfer device using corona discharge, a transfer belt, a transfer roller, or the like can be used.
In addition, in the transfer process, for example, an intermediate transfer member is used, and after a toner image is primarily transferred onto the intermediate transfer member, the toner image is secondarily transferred onto a recording medium. The toner image formed on the photosensitive member can be directly transferred to a recording medium.

(recoding media)
The recording medium (also referred to as media, recording material, recording paper, recording paper, etc.) may be a commonly used one, and is not particularly limited as long as it retains a toner image. Specifically, for example, plain paper from thin paper to thick paper, high quality paper, coated printing paper such as art paper or coated paper, commercially available Japanese paper or postcard paper, OHP plastic film, cloth, soft transparent film And synthetic paper such as YUPO paper.

[Fixing process]
In this step, the toner image transferred to the recording medium is fixed.
The fixing method is not particularly limited, and a known method can be used. Specifically, for example, a method of fixing a toner image transferred on a recording medium by a contact heating type fixing process can be mentioned.

[Step of supplying a compound whose melting point is lowered by light irradiation]
In this step, a compound whose melting point is lowered by light irradiation is supplied before the fixing step.
If it is before the fixing step, it may be before the toner image forming step or after the toner image forming step.
In the step of irradiating light, it is preferable that the compound is present on the toner image serving as the image surface so that the light irradiated to the compound whose melting point is lowered by light irradiation is not blocked by the toner. As a result, in the step of irradiating light, the compound is irradiated with light without being blocked by the toner. As a result, the compound can be effectively melted, and thus fixing at a lower temperature becomes possible. preferable.

  The compound according to the present invention is preferably present on the toner image serving as the image surface before the fixing step. In this case, for example, the compound may be developed / transferred as particles, or may be present on the image surface (on the toner image) by providing a coating mechanism and coating the compound on a photoreceptor or a transfer belt. You may let them.

<Compound whose melting point is lowered by light irradiation>
The compound whose melting point is lowered by light irradiation according to the present invention can be used without particular limitation as long as the melting point is lowered by photoisomerization and solidifies by visible light irradiation or heat.
Specifically, it has a double bond in the molecule, and when irradiated with ultraviolet light, it undergoes isomerization (photo-isomerization) from the trans form to the cis form, resulting in a large change in the molecular shape and the transition from solid to liquid. A compound that exhibits metastasis is preferred.

  Examples of such a compound include a compound containing a site (also referred to as a photoisomerization group) having a structure as represented by the following general formula (1) or (2).

However, in the site of the structure represented by the general formula (1) or (2), A and B are not particularly limited as long as they form a double bond and do not impair the effects of the present invention. An atom is preferred. R _{1 to} R ₆ represent a hydrogen atom and all substituents. R ₃ and R ₄ bonded to A are mutually different substituents, and R ₁ and R ₂ bonded to B are mutually different substituents.

  Further, the compound having photoisomerization may be a low molecular compound or a high molecular compound, and is used for image formation and is not particularly limited as long as it does not affect the image. Is preferred.

  Photoisomerization means that a compound having a double bond in a molecule changes from a more stable trans form to a cis form through an excited state generated by absorbing light energy and vice versa. Say.

  As such a photoisomerization group, an azo group or an ethylenic double bond group is preferable. Furthermore, it is preferable that a group having a benzene ring is bonded to at least one of an azo group and an ethylenic double bond group because they are easily compatible with styrene acrylic and polyester binder resins.

  The group having a benzene ring bonded to an azo group or an ethylenic double bond group may be unsubstituted or may have one or more substituents.

  As a substituent, a linear or branched C1-C30 alkyl group (methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, etc.), linear or branched C1-C30 alkoxy group (methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, etc.), aryloxy (phenyloxy, naphthyloxy, etc.), aralkyloxy (benzyl) Oxy, phenethyloxy, etc.), halogen atoms (F, Cl, Br, I), nitro, cyano, hydroxy, amino, monoalkylamino (methylamino, ethylamino, n-propylamino, isopropylamino, n-butylamino, Isobutylamino, sec-butylamino , Tert-butylamino, etc.), dialkylamino (dimethylamino, diethylamino, di-n-propylamino, diisopropylamino, di-n-butylamino, diisobutylamino, disec-butylamino, ditert-butylamino, etc.), alkanoyl ( Acetyl, propionyl, n-butyryl, isobutyryl, sec-butyryl, tert-butyryl, etc.), acyloxy (acetyloxy, propionyloxy, n-butyryloxy, isobutyryloxy, sec-butyryloxy, tert-butyryloxy, valeryloxy, benzoyloxy) Etc. Moreover, these photoisomerized compounds may be bonded in a plurality of molecules.

  Among the compounds having such a structure, in particular, in the molecule, there are a plurality of functional groups capable of cis-trans photoisomerization, and even in the solid state where the fluidity is lost, the photoisomerization function in the molecule is caused by steric factors. A sugar alcohol ester represented by the following general formula (3) or (4) in which the groups are not tightly packed and is in a state capable of cis-trans photoisomerization is preferred.

  In the general formulas (3) and (4), R is a group having a structure represented by the following general formula (5). n represents an integer of 1 to 4.

In general formula (5), m represents an integer of 0 to 16. k represents an integer of 1 to 16.
Among the sugar alcohol esters represented by the general formula (3) or (4), k is in the range of 6 to 16, m is in the range of 2 to 16, and n is in the range of 1 to 4. Is preferred.

  In the compound represented by the above general formula (3) or (4), a plurality of photoreactive sites are chemically linked. The compound is a compound capable of photoreaction because the degree of freedom of the photoreactive site is reduced due to the presence of this linking moiety, and cannot be arranged, and as a result, does not crystallize.

  When ultraviolet light is irradiated to a compound whose melting point is lowered by light irradiation as described above, it is transferred from a solid state to a fluid liquid by a large change in the molecular structure, and then light is irradiated again at a different wavelength, By heating at a temperature lower than the temperature at which the compound fluidizes or simply leaving it in the dark at room temperature (25 ° C.), the reverse reaction takes place and the fluidity can be lost and solidified again.

  The method for controlling the change in the state of the solid or liquid of the compound according to the present invention by light irradiation will be specifically described using a compound represented by the following chemical formula as an example of the general formula (3) or (4). .

  When the photoisomerization group in the compound represented by the above chemical formula is a trans isomer, the fluidity is lost and becomes a solid, and when it is a cis isomer, the fluidity is imparted and becomes a liquid. In this way, in the case of a photoisomerization group having an azobenzene skeleton, it is isomerized to a cis isomer by irradiating with ultraviolet rays around 365 nm, so that it becomes a liquid and rapidly takes a trans configuration by irradiating visible light around 500 nm. Therefore, it becomes a solid.

The cis isomer is heated at a temperature lower than the temperature at which the compound fluidizes (for example, a temperature lower than the first glass transition point of the toner) or simply left at room temperature (25 ° C.) in a dark place. Gradually changes to the trans form. This is because the energy barrier when isomerizing from the cis isomer to the trans isomer is smaller than when isomerizing from the trans isomer to the cis isomer. That is, it is presumed that isomerization from a cis isomer to a trans isomer can impart energy necessary for isomerization even by heating below the temperature at which the compound fluidizes, including room temperature.
That is, the compound is characterized by having reversibility that becomes a liquid when irradiated with ultraviolet rays around 365 nm and becomes a solid when irradiated with visible light or heated around 500 nm.

As described above, the compound represented by the above chemical formula exhibits a phase transition from a solid to a liquid when irradiated with ultraviolet light. In the present invention, since there is a step of supplying such a compound on the image before the fixing step, light (for example, represented by the above chemical formula) is displayed on the image immediately before or simultaneously with the fixing step. If a compound is used, this compound can be melted by irradiation with ultraviolet light.
Since there is a molten compound liquid on the image at the time of fixing, the toner is plasticized and can be fixed at a low temperature. Therefore, the toner in the developing process, that is, the toner put into the developing device for use in image formation can be set to a high Tg. Therefore, the toner has a high heat-resistant storage property and requires a large amount of heat for fixing. However, an image forming method capable of fixing at low temperature can be provided.

  Specific examples of the compound according to the present invention include azobenzene derivatives having a plurality of substituents as described in International Publication No. 2013/081155 in addition to the above.

[Step of irradiating light]
In the step of irradiating light, the compound is irradiated with light that lowers the melting point.
The light used in the step is not limited as long as the melting point of the compound is lowered. Preferably, the light is ultraviolet light having a wavelength of around 365 nm, specifically, ultraviolet light having a wavelength in the range of 300 to 400 nm. Preferably there is.
As a method for controlling the fluidity of the above-mentioned compound having a lowered melting point by performing light irradiation, adjustment of the exposure amount can be mentioned. The exposure amount varies depending on the type of the light source, and usually 0.5 to 200 J / cm ² , preferably 1.0 to 150 J / cm ² , more preferably 3.0 to 80 J / cm ² . Moreover, it is preferable that light irradiation is performed under the temperature conditions of 10-60 degreeC.
The light source is not particularly limited as long as the above conditions are satisfied. For example, a UV-LED array, a mercury lamp, a metal halide lamp, or the like can be suitably used.

[Step of irradiating visible light]
The image forming method of the present invention may further include a step of irradiating visible light after the fixing step.
When the compound according to the present invention is a compound that changes from a liquid to a solid by visible light, the compound can be efficiently solidified by irradiation with visible light after the fixing step.
Note that the visible light to be irradiated preferably has a wavelength of 400 to 600 nm.
Moreover, it does not specifically limit as an irradiation method, A well-known method can be used, for example, LED, an organic EL element, a fluorescent lamp etc. are mentioned.

[Step of heating at a temperature lower than the first glass transition point of the toner]
The image forming method of the present invention may have a step of heating at a temperature lower than the first glass transition point of the toner after the fixing step instead of or simultaneously with the step of irradiating with visible light. . Accordingly, since the compound according to the present invention can be heated at a temperature lower than the temperature at which the compound is fluidized, the melted compound can be quickly solidified, and thus image sticking can be suppressed.

≪Toner≫
The toner according to the present invention is formed from toner particles obtained by attaching external additive particles to toner base particles. As a method for producing this toner, a known method can be used, which may be a pulverization method or a chemical method, and is not particularly limited, but an emulsion aggregation type toner capable of controlling the particle diameter and shape is preferable.

  The average particle size of the toner particles according to the present invention is 3.0 to 8.0 μm, preferably 4.0 to 7.5 μm in terms of volume average particle size. By being in the above range, the number of toner particles having a large adhesion force that flies at the time of fixing and adheres to the heating member to generate a fixing offset is reduced, and the transfer efficiency is increased to improve the halftone image quality. Image quality such as fine lines and dots is improved. Also, toner fluidity can be secured.

The average particle size of the toner can be controlled by the concentration of the aggregating agent, the amount of the solvent added or the fusing time in the agglomeration and fusing step during the production of the toner, and the composition of the binder resin.
The electrostatic charge image developing toner according to the present invention preferably has an average circularity of 0.920 to 1.000 from the viewpoint of improving transfer efficiency.
The average circularity can be measured using, for example, an average circularity measuring device “FPIA-2100” (manufactured by Sysmex).

  The first glass transition point (Tg) of the toner is preferably 45 to 70 ° C, and more preferably 45 to 60 ° C. When the first glass transition point of the toner is 45 ° C. or higher, it is possible to avoid toner aggregation in a high temperature environment, and as a result, the heat resistant storage property is improved. Moreover, if it is 70 degrees C or less, low temperature fixability can be obtained suitably.

(Measurement method of the first glass transition point)
The first glass transition point can be determined using, for example, “Diamond DSC” (manufactured by PerkinElmer).
The specific procedure for measurement is as described in the examples.

[Toner base particles]
As the toner base particles according to the present invention, known toner base particles can be used. Such toner base particles are specifically composed of toner base particles containing at least a binder resin and, if necessary, a colorant. Further, the toner base particles may further contain other components such as a release agent and a charge control agent, if necessary.

[Binder resin]
A known resin can be used as the binder resin, and for example, an amorphous resin or a crystalline resin can be suitably used.

<Amorphous resin>
The amorphous resin that can be used in the present invention is not particularly limited, but a known amorphous resin such as urethane resin and urea resin can be preferably used in addition to the following vinyl resin and polyester resin. .

(Vinyl resin)
When a vinyl resin is used as the amorphous resin, the vinyl resin is not particularly limited as long as it is obtained by polymerizing a vinyl compound. For example, acrylate resin, styrene-acrylate resin, ethylene / vinyl acetate resin, etc. Is mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.
Among the above vinyl resins, a styrene-acrylic ester resin (styrene acrylic resin) is preferable in consideration of plasticity at the time of heat fixing.
Therefore, although detailed description is omitted, as the styrene monomer, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene; ) Acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, etc .; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate It is preferable to use methacrylic acid esters such as These styrene monomers and (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

Further, other monomers may be polymerized, and examples thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoester. Alkyl ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4- Examples thereof include hydroxybutyl (meth) acrylate and polyethylene glycol mono (meth) acrylate.
The production method of the styrene acrylic resin is not particularly limited, and can be produced by an emulsion polymerization method or the like.

(Polyester resin)
When using a polyester resin as an amorphous resin, among known polyester resins obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol), In differential scanning calorimetry (DSC), it refers to a resin that does not show a clear endothermic peak. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  Examples of the polyvalent carboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid Aliphatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc .; maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, isododecenyl succinic acid, n- Aliphatic unsaturated dicals such as dodecenyl succinic acid and n-octenyl succinic acid Phosphate; trimellitic acid, pyromellitic acid, naphthalene tricarboxylic acid, naphthalene tetracarboxylic acid, pyrene-tricarboxylic acid, and the like divalent or higher carboxylic acids, such as pyrene-tetracarboxylic acid.

  Examples of the polyhydric alcohol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Aliphatic diols such as octadecanediol and 1,20-eicosanediol; Bisphenols such as bisphenol A and bisphenol F; and alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts; glycerin, Pentaerythritol It can be exemplified hexamethylol melamine, hexa ethylene melamine, tetramethylol benzoguanamine, etc. trihydric or higher polyols, such as tetra-ethyl benzoguanamine the.

<Crystalline resin>
The toner base particles according to the present invention may contain a crystalline resin. For example, in addition to the crystalline polyester described below, the crystalline resin described in paragraphs 0043 to 0102 of JP-A No. 2015-011325 may be used. It can be suitably used.

(Crystalline polyester resin)
The crystalline polyester resin is a part derived from a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol), In the differential scanning calorimetry (DSC) of toner, it refers to a resin unit having a clear endothermic peak rather than a stepwise endothermic change. Specifically, the clear endothermic peak means that the half-value width of the endothermic peak is within 15 ° C. when measured at a heating rate of 10 ° C./min in the differential scanning calorimetry (DSC) described in the examples. It means a peak.

  The crystalline polyester resin is not particularly limited as long as it is defined above. For example, the crystalline polyester resin itself may be contained. Alternatively, as a hybrid resin having a crystalline polyester resin unit, a resin having a structure in which other components are copolymerized on the main chain of the crystalline polyester resin unit, or a crystalline polyester resin unit is copolymerized on the main chain composed of other components A resin having such a structure that the toner containing the resin exhibits a clear endothermic peak as described above may be contained.

  The crystalline polyester resin is produced from a polyvalent carboxylic acid component and a polyhydric alcohol component. In this case, the carbon number C (acid) of the polyvalent carboxylic acid component constituting the crystalline polyester resin unit and the carbon number C (alcohol) of the polyhydric alcohol component, and the polyvalent carboxylic acid component and the polyhydric alcohol component The valence of each is preferably 2 to 3 and particularly preferably 2 respectively. Therefore, a case where the valence is 2 respectively (that is, a dicarboxylic acid component and a diol component) will be described as a particularly preferable form.

  As the dicarboxylic acid component, an aliphatic dicarboxylic acid is preferably used, and an aromatic dicarboxylic acid may be used in combination. As the aliphatic dicarboxylic acid, it is preferable to use a linear one. By using a linear type, there is an advantage that crystallinity is improved. The dicarboxylic acid component is not limited to one type, and two or more types may be mixed and used.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (dodecanedioic acid), 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1, Examples thereof include 18-octadecanedicarboxylic acid and cyclohexanedicarboxylic acid, and lower alkyl esters and acid anhydrides thereof can also be used.

  Examples of the aromatic dicarboxylic acid that can be used together with the aliphatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. Is mentioned. Among these, terephthalic acid, isophthalic acid, and t-butylisophthalic acid are preferably used from the viewpoints of availability and emulsification ease.

  As the dicarboxylic acid component for forming the crystalline polyester resin, the content of the aliphatic dicarboxylic acid is preferably 50 constituent mol% or more, more preferably 70 constituent mol% or more, and still more preferably 80 It is at least 100% by mole, particularly preferably 100% by mole. When the content of the aliphatic dicarboxylic acid in the dicarboxylic acid component is 50 constituent mol% or more, the crystallinity of the crystalline polyester resin unit can be sufficiently ensured.

  Moreover, it is preferable to use aliphatic diol as a diol component, and you may contain diols other than aliphatic diol as needed. As the aliphatic diol, a linear diol is preferably used. By using a linear type, there is an advantage that crystallinity is improved. A diol component may be used individually by 1 type and may be used 2 or more types.

  Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,20-eicosanediol.

  Examples of the diol other than the aliphatic diol used as necessary include a diol having a double bond and a diol having a sulfonic acid group. Specifically, examples of the diol having a double bond include 2 -Butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like.

  As the diol component for forming the crystalline polyester resin unit, the content of the aliphatic diol is preferably 50 component mol% or more, more preferably 70 component mol% or more, and still more preferably 80 component mol%. It is at least mol%, particularly preferably 100 constituent mol%. When the content of the aliphatic diol in the diol component is 50 constituent mol% or more, the crystallinity of the crystalline polyester resin unit can be ensured and excellent low-temperature fixability can be obtained in the manufactured toner. Glossiness is obtained in the finally formed image.

  The method for forming the crystalline polyester resin is not particularly limited, and the resin may be formed by polycondensation (esterification) of the polyvalent carboxylic acid and the polyhydric alcohol using a known esterification catalyst. it can.

  The use ratio of the polyhydric alcohol component to the polycarboxylic acid component is such that the equivalent ratio [OH] / [COOH] of the hydroxy group [OH] of the diol component to the carboxy group [COOH] of the dicarboxylic acid component is 1 The ratio is preferably 5/1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, zirconium, Examples thereof include metal compounds such as germanium; phosphorous acid compounds; phosphoric acid compounds; and amine compounds. Specifically, examples of the tin compound include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Titanium compounds include titanium alkoxides such as tetranormal butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxy titanium stearate; titanium tetraacetylacetonate, titanium lactate, titanium triethanolamine Examples thereof include titanium chelates such as nates. Examples of germanium compounds include germanium dioxide. Furthermore, examples of the aluminum compound include oxides such as polyaluminum hydroxide, aluminum alkoxide, and the like, and tributylaluminate and the like can be given. You may use these individually by 1 type or in combination of 2 or more types.

  The polymerization temperature and the polymerization time are not particularly limited, and the inside of the reaction system may be depressurized as necessary during the polymerization.

  Furthermore, in the case of a hybrid resin having a crystalline polyester resin unit, the content of the crystalline polyester resin unit is preferably 50% by mass or more and less than 98% by mass with respect to the total amount of the hybrid resin. By setting it as the above range, sufficient crystallinity can be imparted to the hybrid resin. In addition, the structural component and content rate of each unit in a hybrid resin can be specified by NMR measurement and methylation reaction P-GC / MS measurement, for example.

  Here, the hybrid resin includes an amorphous resin unit other than the polyester resin described in detail below, in addition to the crystalline polyester resin unit. The hybrid resin may be in any form such as a block copolymer or a graft copolymer as long as it includes the crystalline polyester resin unit and an amorphous resin unit other than the polyester resin. A coalescence is preferable. By using a graft copolymer, the orientation of the crystalline polyester resin unit can be easily controlled, and sufficient crystallinity can be imparted to the hybrid resin.

  Furthermore, from the above viewpoint, it is preferable that the crystalline polyester resin unit is grafted with an amorphous resin unit other than the crystalline polyester resin as a main chain. That is, the hybrid crystalline polyester resin is preferably a graft copolymer having an amorphous resin unit other than the polyester resin as a main chain and a crystalline polyester resin unit as a side chain.

  By setting it as the said form, the orientation of a crystalline polyester resin unit can be raised more, and the crystallinity of hybrid resin can be improved.

  In addition, substituents, such as a sulfonic acid group, a carboxy group, and a urethane group, may be further introduced into the hybrid resin. The introduction of the substituent may be in the crystalline polyester resin unit or in an amorphous resin unit other than the polyester resin described in detail below.

(Amorphous resin unit other than polyester resin)
The amorphous resin unit other than the polyester resin is a portion derived from an amorphous resin other than the crystalline polyester resin. The inclusion of an amorphous resin unit in the hybrid resin (and also in the toner) is suitable for NMR measurement, P-GC / MS measurement, methylation reaction P-GC / MS measurement, etc., depending on its structure. The method can be selected and the chemical structure can be characterized.

  In addition, the amorphous resin unit has a relatively high first glass transition point (Tg) having no melting point when differential scanning calorimetry (DSC) is performed on a resin having the same chemical structure and molecular weight as the unit. It is a resin unit having.

  The amorphous resin unit is not particularly limited as long as it is defined above. For example, for a resin having a structure in which other components are copolymerized on the main chain of an amorphous resin unit and a resin having a structure in which an amorphous resin unit is copolymerized on a main chain composed of other components, this resin is used. If the toner to be contained has an amorphous resin unit as described above, the resin corresponds to a hybrid resin having an amorphous resin unit.

  The amorphous resin unit is preferably composed of the same kind of resin as the amorphous resin (that is, a resin other than the hybrid resin) contained in the binder resin. By adopting such a form, the affinity between the hybrid resin and the amorphous resin is further improved, the hybrid resin is more easily taken into the amorphous resin, and the charging uniformity and the like are further improved.

  Here, “the same kind of resin” means that a characteristic chemical bond is commonly contained in the repeating unit. The “characteristic chemical bond” is described in the National Institute for Materials Science (NIMS) Substance / Material Database (http://polymer.nims.go.jp/PoLyInfo/guide/jp/term_polymer.html). Follow “Polymer classification”. That is, polyacryl, polyamide, polyanhydride, polycarbonate, polydiene, polyester, polyhaloolefin, polyimide, polyimine, polyketone, polyolefin, polyether, polyphenylene, polyphosphazene, polysiloxane, polystyrene, polysulfide, polysulfone, polyurethane, polyurea Chemical bonds constituting polymers classified according to a total of 22 types of polyvinyl and other polymers are referred to as “characteristic chemical bonds”.

  In addition, the “same kind of resin” in the case where the resin is a copolymer is characteristic when the monomer type having the above chemical bond is used as a constituent unit in the chemical structure of a plurality of monomer types constituting the copolymer. Refers to resins having common chemical bonds. Therefore, even if the characteristics of the resin itself are different from each other, or even when the molar component ratios of the monomer species constituting the copolymer are different from each other, the same type of chemical bonds are used as long as they have a common chemical bond. Considered resin.

  For example, a resin (or resin unit) formed from styrene, butyl acrylate and acrylic acid and a resin (or resin unit) formed from styrene, butyl acrylate and methacrylic acid have at least chemical bonds constituting polyacryl. These are the same kind of resins. To further illustrate, a resin (or resin unit) formed of styrene, butyl acrylate and acrylic acid and a resin (or resin unit) formed of styrene, butyl acrylate, acrylic acid, terephthalic acid and fumaric acid are mutually As a common chemical bond, it has a chemical bond constituting at least polyacryl. Therefore, these are the same kind of resins.

Although the resin component which comprises an amorphous resin unit is not restrict | limited in particular, For example, a vinyl resin unit, a urethane resin unit, a urea resin unit etc. are mentioned. Among these, a vinyl resin unit is preferable because it is easy to control thermoplasticity.
The vinyl resin unit is not particularly limited as long as a vinyl compound is polymerized, and examples thereof include an acrylic ester resin unit, a styrene-acrylic ester resin unit, and an ethylene / vinyl acetate resin unit. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The method for forming the styrene acrylic resin unit 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 or diazo polymerization initiators and peroxide polymerization initiators.

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

  As the peroxide polymerization initiator, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4 -Dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine and the like.

  Moreover, when forming resin particles by an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide, and the like.

  The content of the amorphous resin unit is preferably 3% by mass or more and 50% by mass or less with respect to the total amount of the hybrid resin. Furthermore, the content is more preferably 5% by mass or more and 30% by mass or less. By setting it as the above range, sufficient crystallinity can be imparted to the hybrid resin.

(Method for producing hybrid crystalline polyester resin (hybrid resin))
The method for producing a hybrid resin contained in the binder resin according to the present invention is a method capable of forming a polymer having a structure in which the crystalline polyester resin unit and the amorphous resin unit are molecularly bonded. There is no particular limitation.

(Coloring agent)
As the colorant that can constitute the toner, carbon black, magnetic material, dye, pigment, etc. can be used arbitrarily. As the carbon black, channel black, furnace black, acetylene black, thermal black, lamp black, etc. are used. Is done. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.

  Examples of the colorant for magenta or red include C.I. I. Pigment Red 2, 3, 5, 6, 7, 15, 16, 48: 1, 48: 3, 53: 1, 57: 1, 60, 63, 64 68, 81, 81: 4, 83, 87, 88, 89, 90, 112, 114, 122, 123, 139, 144, 149, 150 163, 166, 170, 177, 178, 184, 202, 206, 207, 209, 222, 238, 269, and the like.

  Examples of the colorant for orange or yellow include C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 12, 14, 15, 17, 74, 83, 93, 94, 138, 139, 155, 162, 180, 185, C.I. I. Solvent yellow 93 etc. are mentioned.

  Further, examples of the colorant for green or cyan include C.I. I. Pigment Blue 2, 3, 15, 15, 15: 2, 15: 3, 15: 4, 16, 17, 17, 60, 62, 66, C.I. I. And CI Pigment Green 7.

These colorants can be used alone or in combination of two or more as required.
The addition amount of the colorant is preferably 1 to 30% by mass, more preferably 2 to 20% by mass with respect to the whole toner, and a mixture thereof can also be used. Within such a range, the color reproducibility of the image can be ensured.
Further, the colorant dispersion diameter in the toner is preferably 10 to 1000 nm, 50 to 500 nm, and more preferably 80 to 300 nm in terms of volume average particle diameter.

<Release agent>
The release agent constituting the toner is not particularly limited, and known ones can be used. Specifically, for example, polyolefin wax such as polyethylene wax and polypropylene wax, branched chain hydrocarbon wax such as microcrystalline wax, long chain hydrocarbon wax such as paraffin wax and sazol wax, distearyl ketone, etc. Dialkyl ketone wax, carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerol tribehenate, 1,18-octadecane Ester wax such as diol distearate, tristearyl trimellitic acid, distearyl maleate, ethylenediamine behenyl amide, tristearyl amide of trimellitic acid And the like amide-based waxes such as.

  Melting | fusing point of a mold release agent becomes like this. Preferably it is 40-160 degreeC, More preferably, it is 50-120 degreeC. By setting the melting point within the above range, the heat-resistant storage stability of the toner is ensured, and stable toner image formation can be performed without causing cold offset or the like even when fixing at a low temperature. Further, the content of the release agent in the toner is preferably 1 to 30% by mass, more preferably 5 to 20% by mass.

<Charge control agent>
In addition, a charge control agent can be added to the toner base particles according to the present invention as necessary. Various known materials can be used as the charge control agent.

  As the charge control agent, various known compounds that can be dispersed in an aqueous medium can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary Examples include quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

  The content ratio of the charge control agent is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass with respect to the total amount of the binder resin.

<External additive>
From the viewpoint of improving the charging performance, fluidity, and cleaning properties of the toner, particles such as known inorganic fine particles and organic fine particles and a lubricant can be added to the surface of the toner particles as external additives.
Preferred inorganic fine particles include inorganic fine particles made of silica, titania, alumina, strontium titanate, or the like. In particular, from the viewpoint of stress resistance, it is preferable to add a large particle diameter silica having a number average primary particle diameter of about 80 nm to 500 nm.
If necessary, these inorganic fine particles may be hydrophobized.
As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and organic fine particles made of these copolymers can be used.
The lubricant is used for the purpose of further improving the cleaning property and the transfer property. Examples of the lubricant include zinc stearate, salts of aluminum, copper, magnesium, calcium, and zinc oleate. Of higher fatty acids, such as salts of manganese, iron, copper, magnesium, zinc of palmitic acid, salts of copper, magnesium, calcium, zinc of linoleic acid, salts of calcium, zinc of ricinoleic acid, salts of calcium, etc. Metal salts are mentioned. A variety of these external additives may be used in combination.
The amount of the external additive added is preferably 0.1 to 10.0% by mass with respect to 100% by mass of the toner particles.

<Toner production method>
The method for producing the toner according to the present invention is not particularly limited, and examples thereof include known methods such as a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method. The method for producing the toner preferably includes the following external additive treatment step.

(External additive treatment process)
This step is a step of preparing a toner by adding and mixing external additives as necessary to the surface of the toner base particles. Examples of the method of adding the external additive include a method of adding using various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer. By adding the external additive, the fluidity and chargeability of the toner are improved, and the cleaning property is improved.

<Manufacture of developer>
For example, when the toner described above is mixed with a so-called carrier and used as a two-component developer, or when a nonmagnetic toner is used singly, any of them can be suitably used.
Although the carrier which comprises a two-component developer is not specifically limited, The following are mentioned.
As the magnetic material, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used, and in particular, ferrite particles can be used. preferable.
The resin composition for coating the carrier surface is not particularly limited, and for example, olefin resin, cyclohexyl methacrylate-methyl methacrylate copolymer, styrene resin, styrene acrylic resin, silicone resin, ester resin, or fluorine resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, acrylic resin, styrene acrylic resin, polyester resin, fluorine resin, phenol resin, etc. can be used. Can do.
It is also possible to use a so-called resin-dispersed carrier in which the magnetic particles are dispersed in a resin, and a coating layer can be provided on the resin-dispersed carrier.
The volume average particle diameter of the carrier is preferably 15 to 100 μm, more preferably 20 to 60 μm.

≪Electrophotographic image forming device≫
The image forming method of the present invention has at least a charging unit for charging an electrophotographic photosensitive member, an exposure unit, a developing unit, and a transfer unit (primary transfer unit). Thus, the image is fixed by a single fixing device.

  The electrophotographic image forming apparatus using the image forming method of the present invention will be described below. FIG. 1 is a cross-sectional configuration diagram of a full-color electrophotographic image forming apparatus (hereinafter also referred to as “image forming apparatus B”) showing an example of an embodiment of the present invention.

  This full-color image forming apparatus B is called a tandem type color image forming apparatus, and includes four sets of image forming units 10Y, 10M, 10C and 10Bk, an endless belt-shaped intermediate transfer body unit 7a, and a paper feeding means 21. And fixing means 27. A document image reading device SC is disposed above the image forming device B.

  The image forming unit 10Y for forming a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M for forming a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, and It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk are centered around the photoreceptors 1Y, 1M, 1C, or 1Bk, charging means 2Y, 2M, 2C, or 2Bk, and exposure means 3Y, 3M, 3C, or 3Bk. The developing means 4Y, 4M, 4C or 4Bk and the cleaning means 6Y, 6M, 6C or 6Bk for cleaning the photoreceptors 1Y, 1M, 1C or 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of the toner images to be formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. Explained.

  The image forming unit 10Y includes a charging unit 2Y (hereinafter also referred to as “charger 2Y”), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 6Y around a photoconductor 1Y that is an image forming body. A yellow (Y) toner image is formed on the body 1Y. In the present embodiment, in the image forming unit 10Y, at least the photoreceptor 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photoreceptor 1Y. In this embodiment, a corona discharge type charger 2Y is used as the photoreceptor 1Y.

  The exposure unit 3Y is a unit that performs exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charger 2Y, and forms an electrostatic latent image corresponding to a yellow image. As the exposure means 3Y, an exposure element 3Y composed of an LED having light emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element (trade name: SELFOC (registered trademark) lens) or laser optical A system or the like is used.

  The developing means 4Y includes, for example, a developing sleeve and an organic photosensitive member that have a built-in magnet and rotate while holding the developer, and a voltage application that applies a DC and AC bias voltage or a DC or AC bias voltage between the developing sleeve and the developing sleeve. It consists of a device.

  The endless belt-shaped intermediate transfer body unit 7a has an endless belt-shaped intermediate transfer body 70 as a semiconductive endless belt-shaped second image carrier wound around a plurality of rollers and rotatably supported.

Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A recording medium P as a recording medium (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feeding cassette 20 is fed by a paper feeding means 21 and has a plurality of intermediate positions. After passing through the rollers 22A, 22B, 22C, 22D and the registration roller 23, it is conveyed to a secondary transfer roller 5b as a secondary transfer means, and is secondarily transferred onto the recording medium P, and a color image is collectively transferred. The recording medium P onto which the color image has been transferred is fixed by the fixing means 27, is sandwiched between the paper discharge rollers 25, and is discharged from a paper discharge port (not shown). The image forming apparatus B may not have the fixing means 27, in which case, Ru is transferred to a single fixing device A will be described later.

  On the other hand, after the color image is transferred to the recording medium P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 from which the recording medium P is separated by curvature. The

  Further, the housing 8 can be pulled out from the image forming apparatus B through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk, and an endless belt-shaped intermediate transfer body unit 7a.

The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-like intermediate transfer body unit 7a is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7a includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 76, 73, and 74, primary transfer rollers 5Y, 5M, 5C, and 5Bk, and a cleaning unit 6b. It consists of.
In the embodiment described later, when the image forming apparatus B having the above-described mode is used, the fixing unit 27 is taken out from the main body (image forming apparatus B), the image forming apparatus B does not perform fixing, and an unfixed image. Create

<Single fixing device>
FIG. 2 is an example of a single fixing device A (hereinafter also referred to as “remodeling machine A”) that employs the image forming method of the present invention.
The recording medium P is inserted into the single fixing device A from the paper feed port X. The unfixed image discharge port of the “image forming apparatus B” from which the fixing unit 27 is taken out and the paper supply port X can be connected so that the single fixing device A can continuously pass the sheet. The created unfixed image can be manually inserted into the paper feed port X.
Since the image forming method of the present invention includes a step of supplying a compound whose melting point is lowered by light irradiation before the fixing step, the single fixing device A has the photosensitive member 1Ch and the melting point is lowered by light irradiation. It is preferable to have a detachable developing device 10Ch as means for supplying the compound.
This developing device 10Ch has the same charging means, exposure means, developing means, and cleaning means (all not shown) as the image forming unit 10Y, and the melting point is lowered on the photoreceptor 1Ch by the light irradiation according to the present invention. An image made of the compound is formed on the unfixed image.

The single fixing device A has means 4Ch for irradiating an image made of a compound whose melting point is lowered by light irradiation formed on the unfixed image by the developing device 10Ch described above.
The means 4Ch for irradiating such light is not particularly limited, and a known one can be used. For example, as described above, a UV-LED array or the like can be arranged.
By this light irradiating means, an image made of a compound having a melting point lowered by light irradiation formed on the unfixed image is irradiated with light, the compound is photoisomerized, and the liquid is formed on the unfixed image. Become.

  The unfixed image having the above-mentioned compound that has been photoisomerized and turned into a liquid is heated and fixed by a heating roller 24 as a fixing unit.

The compound whose melting point is lowered by light irradiation according to the present invention may be supplied, for example, by charging the compound in place of the toner into the image forming unit 10Y of the electrophotographic image forming apparatus. In this case, the developing device 10Ch may be removed from the single fixing device A.
In this case, the fixing unit 27 has a light source (not shown) and has a step of irradiating light and melting the compound (that is, a step of irradiating light) immediately before or simultaneously with the fixing step. Is preferred.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

[Preparation of toner base particles 1]
The toner base particles 1 were produced as follows.

(Preparation of resin particle dispersion 1)
206 parts by mass of styrene, 86 parts by mass of butyl acrylate, and 20.4 parts by mass of methacrylic acid were mixed, and this monomer mixture was heated to 80 ° C. with stirring, and 139 parts by mass of behenyl behenate was gradually added and dissolved. The monomer solution was prepared.

  Next, a surfactant aqueous solution obtained by dissolving 3 parts by mass of the anionic surfactant “dodecylbenzenesulfonic acid” in 40 parts by mass of pure water is heated to 80 ° C., the monomer solution is added, and high-speed stirring is performed. A monomer dispersion was prepared.

  Next, 1298 parts by mass of pure water was put into a polymerization apparatus equipped with a stirrer, a cooling pipe, a temperature sensor, and a nitrogen introduction pipe, and the internal temperature was raised to 80 ° C. while stirring under a nitrogen stream. The monomer dispersion was charged into this polymerization apparatus, and a polymerization initiator aqueous solution in which 3.9 parts by mass of potassium persulfate was dissolved in 74.5 parts by mass of pure water was added.

  After adding the polymerization initiator aqueous solution, 3.55 parts by mass of n-octyl mercaptan was added over 5 minutes, and polymerization was further performed at 80 ° C. for 2 hours. Next, a polymerization initiator aqueous solution in which 6.3 parts by mass of potassium persulfate was dissolved in 120.5 parts by mass of pure water was added, 279.4 parts by mass of styrene, 116.4 parts by mass of butyl acrylate, 27.5 parts of methacrylic acid. A monomer solution mixed with 6.8 parts by mass of n parts octyl mercaptan was added dropwise over 1 hour. After the monomer solution was dropped, the polymerization treatment was continued for 2 hours, and then cooled to room temperature to prepare “resin particle dispersion 1”.

(Preparation of resin particle dispersion for shell)
After adding 2929 parts by mass of pure water and 2 parts by mass of the anionic surfactant “dodecylbenzenesulfonic acid” to a reaction apparatus equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe, and a temperature sensor, Warm to 80 ° C under.
Next, a monomer solution in which 502 parts by mass of styrene, 185 parts by mass of butyl acrylate, 112 parts by mass of methacrylic acid and 13.9 parts by mass of n-octyl mercaptan and 10.2 parts by mass of potassium persulfate are added to 194 parts by mass of pure water. A dissolved polymerization initiator aqueous solution was prepared. After the polymerization initiator aqueous solution is charged into the reactor, the monomer mixture is dropped over 3 hours, and further polymerized for 1 hour, and then cooled to room temperature to produce a “resin particle dispersion for shell”. did. The weight average molecular weight of the shell tree particles was 13200, and the mass average particle diameter was 82 nm.

(Preparation of carbon black dispersion)
Dissolve 11.5 parts by mass of sodium n-dodecyl sulfate in 1600 parts by mass of pure water, gradually add 230 parts by mass of carbon black “MOGAL L”, and then add “Clearmix W Motion CLM-0.8 (M Technique) “Carbon black dispersion” having a median diameter of 160 nm on a number basis was prepared.

(Formation of toner base particles 1)
“Resin particle dispersion 1” prepared above was 412 parts by mass in terms of solids, 746 parts by mass of ion-exchanged water, and 43 parts by mass of the “carbon black dispersion” in terms of solids were agitator, temperature sensor, cooling The reactor was charged with a tube. The temperature in the container was kept at 30 ° C., and the pH was adjusted to 10 by adding a 5 mol / L sodium hydroxide aqueous solution.
Next, an aqueous solution in which 47.5 parts by mass of magnesium chloride hexahydrate is dissolved in 47.5 parts by mass of ion-exchanged water is dropped over 10 minutes with stirring, and then the temperature is raised to 85 ° C. to form a dispersion. The contained particles were aggregated and fused. The “Coulter Counter 3 (manufactured by Beckman Coulter)” was used as it was, and the heating and stirring were continued until the volume-based median diameter (D50) became 6.8 μm.

When the median diameter (D50) on the volume basis reaches 6.8 μm, 24 parts by mass of “resin particle dispersion for shell” is added in terms of solid content and stirred for 1 hour to melt the shell particles on the surface. I wore it.
Further, stirring is continued as it is for 30 minutes to completely form the shell, and then an aqueous sodium chloride solution in which 52 parts by mass of sodium chloride is dissolved in 207 parts by mass of ion-exchanged water is added, and the internal temperature is raised to 90 ° C. Stirring was continued for 4 hours and then cooled to room temperature (25 ° C.) to form particles. The formed particles were repeatedly washed with ion-exchanged water and then dried with hot air at 35 ° C. to obtain “toner base particles 1”.

  The median diameter (D50) of the obtained “toner base particles 1” on a volume basis was measured using “Coulter Counter 3 (manufactured by Beckman Coulter)” to be 7.0 μm.

[Preparation of toner base particles 2]
(Preparation of resin particle dispersion 2)
198 parts by weight of styrene, 92 parts by weight of butyl acrylate and 20.4 parts by weight of methacrylic acid were mixed, and this monomer mixture was heated to 80 ° C. while stirring, and 139 parts by weight of behenyl behenate was gradually added and dissolved. The monomer solution was prepared.
Next, a surfactant aqueous solution obtained by dissolving 3 parts by mass of the anionic surfactant “dodecylbenzenesulfonic acid” in 40 parts by mass of pure water is heated to 80 ° C., the monomer solution is added, and high-speed stirring is performed. A monomer dispersion was prepared.

  Next, 1298 parts by mass of pure water was put into a polymerization apparatus equipped with a stirrer, a cooling pipe, a temperature sensor, and a nitrogen introduction pipe, and the internal temperature was raised to 80 ° C. while stirring under a nitrogen stream. The monomer dispersion was charged into this polymerization apparatus, and a polymerization initiator aqueous solution in which 3.9 parts by mass of potassium persulfate was dissolved in 74.5 parts by mass of pure water was added.

  After adding the polymerization initiator aqueous solution, 3.55 parts by mass of n-octyl mercaptan was added over 5 minutes, and polymerization was further performed at 80 ° C. for 2 hours. Next, a polymerization initiator aqueous solution in which 6.3 parts by mass of potassium persulfate was dissolved in 120.5 parts by mass of pure water was added, 270.5 parts by mass of styrene, 125.3 parts by mass of butyl acrylate, 27.5 parts of methacrylic acid. A monomer solution mixed with 6.8 parts by mass of n parts octyl mercaptan was added dropwise over 1 hour. After the monomer solution was dropped, the polymerization treatment was continued for 2 hours, and then cooled to room temperature to prepare “resin particle dispersion 2”.

(Formation of toner base particles 2)
Toner base particles 2 were prepared in the same manner as in the preparation of toner base particles 1 except that “resin particle dispersion 1” was changed to “resin particle dispersion 2”. The median diameter (D50) of the obtained “toner base particles 2” on a volume basis was measured using “Coulter Counter 3 (manufactured by Beckman Coulter)” to be 7.0 μm.

<Creation of carrier>
Coating fine particles (weight average molecular weight: 400,000, glass transition point: 115 ° C., median diameter) consisting of 100 parts by mass of 50 μm ferrite particles, cyclohexyl methacrylate and methyl methacrylate copolymer (copolymerization ratio 1: 1) (D50): 100 nm) A carrier raw material consisting of 5.0 parts by mass was charged into a “high-speed stirring mixer with stirring blades”, and was mixed and stirred at a peripheral speed of 1 m / sec for 2 minutes as a preliminary mixing step. Thereafter, as a carrier intermediate formation step, cold water was passed through the jacket, and was mixed and stirred at 40 ° C. and a peripheral speed of 8 m / sec for 20 minutes to form a carrier intermediate. Thereafter, as a carrier particle forming step, steam was passed through the jacket, and the carrier intermediate was stirred at 120 ° C. at a peripheral speed of 8 m / sec for 30 minutes to prepare “Carrier 1” composed of resin-coated carrier particles. The volume-based median diameter was 53 μm, and the thickness of the resin coating layer was 2.5 μm.

[Production of toner]
(Preparation of Toner 1)
In “toner base particle 1”, hydrophobic silica 1 (number average primary particle size 12 nm) is 0.3 mass%, hydrophobic silica 2 (number average primary particle size 100 nm) is 1 mass%, and hydrophobic titanium dioxide (number). 0.5% by mass of an average primary particle size of 20 nm) was added. After a mixing process using a Henschel mixer (manufactured by Nippon Coke Kogyo Co., Ltd.), coarse particles were removed using a sieve having a mesh opening of 45 μm to prepare toner 1.

(Preparation of Toner 2)
Toner 1 was prepared in the same manner as in preparation of toner 1 except that “toner base particle 1” was changed to “toner base particle 2”.

<Method for Measuring Tg and Tsp of Toner 1 and Toner 2>
Tg and Tsp of toner 1 and toner 2 were measured as follows. The results were as shown in Table 1.

(Measurement method of first glass transition point (Tg))
The 1st glass transition point was calculated | required using "Diamond DSC" (made by Perkin Elmer).
As a measurement procedure, first, 3.0 mg of a sample was precisely weighed to two digits after the decimal point, sealed in an aluminum pan, and set in a holder. The reference used an empty aluminum pan. As measurement conditions, measurement temperature is 0 to 200 ° C., temperature increase rate is 10 ° C./min, temperature decrease rate is 10 ° C./min, and temperature control of temperature increase / decrease / temperature increase is performed. Based on the analysis. The glass transition point draws a tangent line indicating the maximum slope between the extension line of the baseline before the rise of the first endothermic peak and the peak of the first peak to the peak vertex, and the intersection is defined as the first glass transition point. As shown.

<Measurement method of softening point (Tsp)>
The softening point (Tsp) of the toner was measured as follows.
First, in an environment of 20 ° C. ± 1 ° C. and 50% ± 5% RH, 1.1 g of the sample toner was placed in a petri dish and leveled, and left for 12 hours or more.
Thereafter, the molded product was “SSP-10A” (manufactured by Shimadzu Corporation) with a pressure of 3820 kg / cm ² for 30 seconds to produce a cylindrical molded sample having a diameter of 1 cm.
Next, this molded sample was preheated with a load of 196 N (20 kgf), a starting temperature of 60 ° C. and a flow tester “CFT-500D” (manufactured by Shimadzu Corporation) in an environment of 24 ° C. ± 5 ° C. and 50% ± 10% RH. It was extruded from the end of preheating from a hole in a cylindrical die (1 mm diameter × 1 mm) using a piston with a diameter of 1 cm at a temperature rising rate of 6 ° C./min for 300 seconds.
The offset method temperature Toffset measured at a setting of an offset value of 5 mm by the melting temperature measurement method of the temperature raising method was used as the softening point of the toner.

<Evaluation method of heat-resistant storage stability of toner 1 and toner 2>
Take 0.5 g of sample toner in a 10 mL glass bottle with an inner diameter of 21 mm, close the lid, shake 600 times at room temperature with Tap Denser KYT-2000 (manufactured by Seishin Enterprise), and then remove the lid at 55 ° C. It was left for 2 hours in an environment of 35% RH. Next, place the toner on a 48-mesh (mesh 350 μm) sieve, taking care not to crush the toner aggregates, set the powder tester (manufactured by Hosokawa Micron), and fix it with a press bar and knob nut. After adjusting the vibration strength to a feed width of 1 mm and applying vibration for 10 seconds, the ratio (mass%) of the amount of toner remaining on the sieve was measured.

The toner aggregation rate is a value calculated by the following formula.
(Toner aggregation rate (%)) = (Mass of residual toner on sieve (g)) / 0.5 (g) × 100

The heat resistant storage stability of the toner was evaluated according to the criteria described below. The results are shown in Table 1.
A: The toner aggregation rate is less than 15% by mass (the toner has excellent heat storage stability and can be used).
○: The toner aggregation rate is in the range of 15 to 20% by mass (the toner has good heat-resistant storage stability and can be used).
Δ: The toner aggregation rate is larger than 20% and 30% or less (the heat-resistant storage stability of the toner is somewhat difficult. Usable)
X: The toner aggregation rate exceeds 30% (toner's heat-resistant storage property is extremely poor. Cannot be used)

[Production of developer]
The carrier and the toner were mixed so that the toner concentration was 7.0% by mass, and Developer 1 and Developer 2 were produced.

<Preparation of Compound 1 Supply Mixture>
Compound 1 shown below (D-mannitol hexakis [11- [4-[(4-hexylphenyl) azo] phenoxy] undecanoate]) (manufactured by Tokyo Chemical Industry) in a mortar until coarse particles disappear. Crushed. The number particle average diameter of these particles was 15 μm. This was mixed with a carrier so as to have a particle concentration of 5% to prepare a mixture for supplying Compound 1.

[Fixability evaluation]
Hereinafter, in each of Examples and Comparative Examples described later, the fixability was evaluated as follows.

The unfixed image used for the evaluation was prepared using a copying machine “bizhub PRO C6500” (manufactured by Konica Minolta, see FIG. 1) with the fixing device removed. For fixing, a developing device capable of developing / transferring Compound 1 to an unfixed image is arranged, and is modified so that it can be irradiated with ultraviolet light for an arbitrary period of time, as shown in FIG. Was used to conduct a fixing experiment.
Specifically, the remodeling machine A includes a detachable developing device 10Ch in which a plurality of UV-LED arrays (wavelength: 365 nm), which are means 4Ch for irradiating light, are installed, a drum-shaped photoconductor 1Ch, a heating device An apparatus having a roller 24. Furthermore, the remodeling machine A is heated after the photoisomerization step in which the compound 1 is photoisomerized (photoirradiation condition: 60 J / cm ² ) by staying in the apparatus for an arbitrary time, and the photoisomerization step. The roller 24 (fixing means) was modified so that the surface temperature (fixing temperature) could be changed in the range of 100 to 200 ° C. and the fixing speed could be varied. The unfixed image was passed through the remodeling machine A, and the fixability was evaluated.

The actual evaluation was 5 cm × 5 cm with a toner adhesion amount of 4 g / m ² at the center of 5 cm from the tip of A4 size high-quality paper in an environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH). A fixing experiment for fixing a solid image was repeatedly performed up to 200 ° C. while the fixing speed was set to 100 mm / sec and the fixing temperature was changed from 100 ° C. in increments of 5 ° C.

In the photoisomerization step, the residence time was set to 30 minutes in order to sufficiently exhibit the isomerization effect.
Among fixing experiments in which image staining due to low temperature offset was not visually observed, the lowest fixing temperature was evaluated as the minimum fixing temperature.
The lower the temperature, the better the low-temperature fixability.

[Example 1]
The mixture for supplying compound 1 is charged into the image forming unit 10Y that forms a yellow image of “bizhub PRO C6500” with the fixing device removed (compound supplying step 1 shown in Table 2) to form a Magenta color image. The developer of toner 1 was put into the image forming unit 10M, and a 5 cm × 5 cm unfixed image patch in which the compound 1 was laminated on the toner 1 was produced in the number necessary for the fixing experiment. At this time, the image forming unit 10Y is used not as a means for forming a yellow image but as a compound supply means. In addition, the supply amount of the compound 1 calculated | required by supplying on white paper was 0.5 g / m < ² >.

  Using the remodeling machine A with the developing device 10Ch removed, the unfixed images obtained above were fixed one by one. At that time, after being allowed to stay in the photoisomerization step for 30 minutes, the fixing temperature is changed from 100 ° C. to 200 ° C. in increments of 5 ° C., and a fixing test is performed. The fixing temperature was used. The minimum fixing temperature for this experiment was 120 ° C.

[Example 2]
The developer of toner 1 was put into the image forming unit 10M for forming the Magenta image of “bizhub PRO C6500” with the fixing device removed, and the number of unfixed image patches of 5 cm × 5 cm of toner 1 required for the fixing experiment was created. .
The compound 1 supply mixture is charged into the developing device 10Ch of the remodeling machine A (“compound supply step 2” described in Table 2), and developed / transferred onto the unfixed image obtained above, and the toner 1 An unfixed image of 5 cm × 5 cm, in which compound 1 was laminated, was fixed one by one. At that time, after being allowed to stay in the photoisomerization step for 30 minutes, the fixing temperature is changed from 100 ° C. to 200 ° C. in increments of 5 ° C., and a fixing test is performed. The fixing temperature was used. The minimum fixing temperature for this experiment was 120 ° C. In addition, the supply amount of the compound 1 calculated | required by supplying on white paper was 0.5 g / m < ² >.

[Example 3]
The developer of toner 1 is charged into an image forming unit 10C that forms a cyan image of “bizhub PRO C6500” with the fixing device removed, and the mixture for supplying compound 1 is charged into an image forming unit 10Bk that forms a black image. The number of unfixed image patches of 5 cm × 5 cm in which the toner 1 was laminated on 1 was prepared as required for the fixing experiment. At this time, the image forming unit 10Bk is used not as a means for forming a black image but as a compound supply means.
This method is referred to as a compound supply step 3.
Using the remodeling machine A with the developing device 10Ch removed, the unfixed images obtained above were fixed one by one. At that time, after being allowed to stay in the photoisomerization step for 30 minutes, the fixing temperature is changed from 100 ° C. to 200 ° C. in increments of 5 ° C., and a fixing test is performed. The fixing temperature was used. The minimum fixing temperature for this experiment was 140 ° C. In addition, the supply amount of the compound 1 calculated | required by supplying on white paper was 0.5 g / m < ² >.

[Example 4]
The compound 1 supply mixture is charged into the image forming unit 10Y that forms the yellow image of “bizhub PRO C6500” with the fixing device removed, and the developer of toner 1 is charged into the image forming unit 10M that forms the Magenta image. A 5 cm × 5 cm unfixed image patch in which the compound 1 was laminated on the toner 1 was prepared in the number necessary for the fixing experiment. At this time, the image forming unit 10Y is used not as a means for forming a yellow image but as a compound supply means. In addition, the supply amount of the compound 1 calculated | required by supplying on white paper was 0.5 g / m < ² >.

  Using the remodeling machine A with the developing device 10Ch removed, the unfixed images obtained above were fixed one by one. At that time, after being allowed to stay in the photoisomerization step for 30 minutes, the fixing temperature is changed from 100 ° C. to 200 ° C. in increments of 5 ° C., and a fixing test is performed. The fixing temperature was used. The minimum fixing temperature for this experiment was 120 ° C.

[Example 5]
A fixing test was performed in the same manner as in Example 1 except that the toner 1 was changed to the toner 2. The minimum fixing temperature for this experiment was 110 ° C.

[Example 6]
A fixing test was conducted in the same manner as in Example 2 except that the toner 1 was changed to the toner 2. The minimum fixing temperature for this experiment was 110 ° C.

[Comparative Example 1]
The developer of toner 1 was put into the image forming unit 10M for forming the Magenta image of “bizhub PRO C6500” with the fixing device removed, and the number of unfixed image patches of 5 cm × 5 cm of toner 1 required for the fixing experiment was created. . Using the remodeling machine A with the developing device 10Ch removed, the unfixed images obtained above were fixed one by one. At that time, after being allowed to stay in the photoisomerization step for 30 minutes, the fixing temperature is changed from 100 ° C. to 200 ° C. in increments of 5 ° C., and a fixing test is performed. The fixing temperature was used. The minimum fixing temperature for this experiment was 160 ° C.

[Comparative Example 2]
A fixing test was performed in the same manner as in Comparative Example 1 except that the toner 1 was changed to the toner 2. The minimum fixing temperature for this experiment was 150 ° C.

<Evaluation with image sticking>
(With visible light irradiation (Examples 1-3, 5, 6, Comparative Examples 1 and 2))
Among the images passed through the fixing means (heating roller 24) of the remodeling machine A, in an image fixed at the minimum fixing temperature + 10 ° C. at which a low temperature offset is not visually observed, immediately after passing the paper, room temperature (25 ° C .: Table 2) after irradiating 500 nm visible light for 5 minutes, folding the image patch part in half, placing the weight at 80 g / cm ^2, and leaving it for 2 hours Slowly open the paper and evaluate the image sticking. At this time, the images did not stick at all (indicated as “◎” in Table 2).

(No visible light irradiation (Example 4))
Among images that have passed through the fixing means (heating roller 24) of the remodeling machine A, an image that is fixed at the minimum fixing temperature + 10 ° C. (that is, 130 ° C.) at which low temperature offset is not visually observed is dark immediately after passing the paper. 5 minutes at room temperature (25 ° C .: “temperature during solidification” described in Table 2), then fold the image patch part in half and place a weight to 80 g / cm ² and leave for 2 hours After that, the paper was slowly opened to evaluate the image sticking. At this time, the images were slightly adhered to each other, but the image did not become defective such as peeling off, so that it was at a level where there was no practical problem (indicated as “◯” in Table 2).

(No visible light irradiation (Example 7))
Of the images passed through the fixing means (heating roller 24) of the remodeling machine A, in an image fixed at the minimum fixing temperature + 10 ° C. (that is, 130 ° C.) where no low temperature offset is visually observed, immediately after passing the paper, After blocking the light and leaving it in a thermostatic chamber set at 40 ° C. (the “temperature during solidification” described in Table 2), which is a temperature lower than the first glass transition point of toner 1, the image patch portion is halved. Folded and placed a weight to 80 g / cm ² and left for 2 hours, then slowly opened the paper and evaluated image sticking. At this time, the images did not stick at all (indicated as “◎” in Table 2).

(Summary)
Table 2 shows that the configuration of the present invention can provide an image forming method capable of fixing at a low temperature while using a toner having high heat-resistant storage property.
In particular, from the comparison between Examples 1 to 3 and 7 and Comparative Example 2, the image forming method of the present invention is the case where the toner 1 having high heat storage stability (high Tg, Tsp, etc.) is used. However, it can be seen that a lower fixing temperature can be realized than the toner 2 having low heat resistance and storage stability (low Tg, Tsp, etc.).
In the present invention, the toner used for image formation is not significantly different from the toner used so far as long as the heat-resistant storage property is secured. There was no defect such as image fogging.

1Ch Photosensitive member 4Ch Light irradiation means 10Y, 10M, 10C, 10Bk Image forming unit 10Ch Development device 24 Heating roller 27 Fixing means A Fixing device (remodeling machine)
P Recording medium

Claims (11)

Developing a toner image by developing the electrostatic latent image formed on the photoreceptor with toner, transferring the toner image to a recording medium, and irradiating the toner image on the recording medium with light An image forming method comprising: irradiating light that lowers the melting point of the compound in the presence of the compound that lowers the melting point by the step of fixing a toner image on the recording medium ,
An image forming method comprising separately forming the toner image and supplying the compound . The image forming method according to claim 1, wherein the supply of pre hear compound is a before forming the toner image. Before the supply of the ineffective compound The image forming method according to claim 1, characterized in that is later formation of the toner image. The image forming method according to claim 1, wherein the compound is present on the toner image in the step of irradiating the light. The image forming method according to any one of claims 1 to 4, wherein the compound is supplied as particles. The image forming method according to any one of claims 1 to 4, wherein the compound is supplied by coating the compound. The image forming method according to claim 1, wherein the compound is a photoisomerizable compound. The image forming method according to claim 1, wherein the light irradiated to the compound is ultraviolet light. After said fixing to step image forming method according to any one of claims 1 to 8 comprising the step of irradiating with visible light. After said fixing to step image forming method according to any one of claims 1 to 9 comprising the step of heating at a temperature lower than the first glass transition point of the toner. The first glass transition point of the toner is, the image forming method according to any one of claims 1 to 10, characterized in that at 45 ° C. or higher.

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