JP2005115194A - Toner, toner manufacturing method, image forming method, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner having a capsule structure suitable for flash fixing and to provide a method for manufacturing toner, an image forming method and an image forming apparatus. <P>SOLUTION: In the toner which is transferred in a desired image pattern onto an image recording medium and fixed by heating at a predetermined fixing temperature, the toner comprises the following agents. They are: a core agent 2 containing a heat generating substance by the effect of light (a colorant 2a and a light absorbent 2b) which receives light to generate heat and a phase transition substance 2c which causes phase transition accompanying volume expansion at a predetermined temperature between room temperature and the above fixing temperature; and a shell agent 3 essentially containing a thermosetting resin which covers the core agent 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner, a toner manufacturing method, an image forming method, and an image forming apparatus.

  Conventionally, as an electrophotographic image forming method, after applying a uniform electrostatic charge to a photoconductive insulator such as a photosensitive drum, an electrostatic image is formed by irradiating the surface with a light image, The electrostatic latent image is developed with toner to form a toner image, the toner image is transferred onto a recording medium such as paper, and then the toner image is melt-fixed on the recording medium to form an image composed of a fixed toner image. The method of obtaining is widely adopted.

  To fix a toner image on a recording medium, there are various fixing methods such as pressure fixing, heat fixing, solvent vapor fixing, and light fixing, and these are fixed alone or in combination. Among these fixing methods, a light fixing method in which a toner image is irradiated with strong light and the toner image is melted with the light energy has attracted particular attention for the following reasons.

  (1) Since non-contact fixing is used, the image is not blurred or dust is not generated in the fixing process, so that the resolution is hardly deteriorated.

  (2) The waiting time after power-on of the image forming apparatus is short, and a quick start is possible.

  (3) Since there is no heating device in the fixing device, there is no risk of fire even when paper is jammed in the fixing device due to a system down or the like.

  (4) Fixing is possible regardless of the material and thickness of the recording medium, such as glued paper, preprinted paper, and paper of different thickness.

  Currently, the most common method in the light fixing method is a flash fixing method using a xenon flash lamp as a light source.

  In this flash fixing system, the toner absorbs light energy and generates heat, and the toner is melted and fixed by the generated heat.

  Since the xenon flash lamp generally used in this flash fixing method has a particularly strong emission intensity in the near infrared region of 800 nm to 1000 nm, the toner for the flash fixing method has high light absorption in the above region. It is required to be.

  As described above, the flash fixing method has many advantages, but also has a disadvantage as compared with the heat roller fixing method that has been widely used. For example, in the heat roller fixing method, since the toner image is directly heated and melted by passing between the pressure rollers, a high fixing property can be obtained relatively easily, whereas in the flash fixing method, Since it is a non-contact fixing method, it is difficult to obtain a high fixing property because the permeability of the melted toner to the paper is low, and a satisfactory fixing performance cannot always be obtained.

  Therefore, the following measures are taken for the purpose of improving the toner fixing property in the flash fixing method.

  (1) Increase the light absorption efficiency of the toner. Specifically, carbon which is a black pigment having high light absorption is used as the colorant.

  (2) Control the melting characteristics of the toner. Specifically, the toner melting characteristics are controlled using a toner binder resin having a specific composition and molecular weight distribution so as to lower the melting point of the toner and lower the viscosity at the time of melting (for example, Patent Document 1). reference.).

  (3) A material for improving fixability is added to the toner. Specifically, a low-melting-point material such as polyolefin is added to the toner as a fixing aid (see, for example, Patent Document 2).

  However, easily meltable toners such as (2) and (3) are prone to agglomeration phenomenon called blocking or caking in a high temperature environment, and a toner having a satisfactory fixing performance is not always obtained. It is not done.

  In addition, a toner in which a core having high fixability is coated with a hard shell agent to form a capsule has been studied. The capsule-shaped toner can be roughly classified into two types, that is, a heat roller fixing method and a flash fixing method.

  As a toner for a heat roller fixing system, a method of forming a microcapsule type toner by using an ink in which a colorant is dispersed in a volatile solvent such as n-pentane as a core agent and covering it with a shell agent is disclosed. (For example, refer to Patent Document 3). However, the toner formed by this method cannot be used for a flash fixing system because the flash light absorption efficiency of the core agent is low. Even if a light-absorbing material is added to the core material to improve the flash light absorption efficiency, the core material is volatile. There is a problem, and there is also a problem that the shell agent is not fixed to the paper and causes a problem.

  Further, for example, Patent Document 4, Patent Document 5, Patent Document 6, Patent Document 7, and the like disclose microcapsule toners formed by coating a low softening point substance with a thermoplastic resin. However, all of these toners are designed so that the shell agent is destroyed by the pressure of the heat roll, so even if it is applied to the non-contact type flash fixing method, the core agent breaks the glaze. It is difficult to expect to elute. These toners were developed mainly for the purpose of improving the offset of the core material to the heat roller when it is fixed by the heat roller, so that sufficient toner fixability can be obtained by the flash fixing method. Absent.

  On the other hand, a fixing method in which a microcapsule toner obtained by coating a core material having a low melt viscosity with a hard shell agent is used as a light fixing toner. For example, Patent Document 8 discloses a microcapsule toner composed of a liquid ink core and a photodegradable resin shell. In this method, the shell agent is photolyzed and destroyed by light irradiation, and the exposed core component penetrates into the paper and is fixed. However, this method is not practical because the photodegradation rate of the shell resin is slow and long-time light irradiation is required to destroy the shell agent.

Further, for example, Patent Document 9 discloses a color toner that prevents a reduction in fixing strength by using a microcapsule toner having a light absorption rate increased by coloring a shell agent black as a color toner for flash fixing. Proposed. However, this method does not provide sufficient fixability, and the color toner color becomes cloudy due to the black colored shell, or the black colorant present on the toner surface adversely affects the chargeability of the toner. Have problems such as.
JP-A-2-158747 (page 1-3) JP 50-28840 (page 4-5) JP 7-56383 A (page 2-3) JP-A-9-292735 (page 4-5) Japanese Patent No. 3038465 (page 3-4) JP-A-10-228130 (page 5-6) JP-A-1-195458 (page 3-5) JP 2000-162814 A (page 4-6, Fig. 1-4) JP-A-2-083550 (page 2-3)

    As described above, various proposals have been made to improve the toner fixing performance in the flash fixing method. Even when capsule-type toner is used, the shell agent is melted and decomposed by flash light as described above. In the present situation, sufficient fixing performance is not obtained by the method of exposing and fixing the core component.

  In view of the above circumstances, an object of the present invention is to provide a toner having a capsule structure suitable for flash fixing, a toner manufacturing method, an image forming method, and an image forming apparatus.

The toner of the present invention that achieves the above object provides:
In toner that is transferred onto an image recording medium and transferred to a desired image pattern and fixed by being heated to a predetermined fixing temperature,
A core comprising a phase transition material that undergoes phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light;
It has the shell agent which coat | covers the said core agent and has thermosetting resin as a main component.

  According to the toner of the present invention, as described above, the photogenic substance and the phase transition substance are contained in the core, so that the photothermal substance in the core is heated by light irradiation, and the Since the phase change material expands rapidly due to heat generation and destroys the shell agent, high fixing performance can be obtained. In addition, since the core is coated with a shell mainly composed of a thermosetting resin, the heat resistance of the toner can be improved, and for example, blocking and caking are prevented even in a high temperature environment. The

  Here, the light-generating substance may be a colorant or a light absorber.

  As described above, when a colorant is used as the light-generating substance, the colorant itself generates heat, so that it is not necessary to add a light absorber. In addition, when a light absorber is used as the light-generating substance, the color of the light absorber itself colors the recording medium, so that it is not necessary to add a colorant.

  Further, the photo-exothermic substance may be an infrared absorber that generates heat by absorbing infrared rays, or may be a heat ray absorber that generates heat by absorbing heat rays.

  As described above, when an infrared absorber or a heat ray absorber is used as the photothermal material, it is more efficient than fixing by a flash fixing device using a visible light source and a toner using a visible light absorber as a photothermal material. Good fixing can be performed.

  The thermosetting resin may be a melamine resin.

  As described above, when a melamine resin is used as the thermosetting resin, a microcapsule toner suitable for flash fixing can be easily obtained due to the high heat resistance of the melamine resin.

  Further, the phase change material may be a wax having a melting point of 100 ° C. or lower.

  As described above, when a wax having a melting point of 100 ° C. or lower is used as the phase change material, the toner undergoes a phase transition at a relatively low temperature of 100 ° C. or lower and rapidly expands. Toner can be obtained.

In addition, the image forming method of the present invention that achieves the above-described object includes:
A core comprising a phase transition material that undergoes phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light, and a thermosetting coating the core. A toner image is formed using a toner having a shell mainly composed of a resin,
The toner image is transferred onto an image recording medium,
The toner image is fixed on the image recording medium by irradiating the toner image on the image recording medium with light.

  According to the image forming method of the present invention, the photo-heating substance and the phase change substance are contained in the toner core, so that the photo-heating substance in the core is irradiated with light and generates heat. As a result, the phase transition material rapidly expands and destroys the toner shell, so that fixing can be performed with high fixing performance.

The image forming apparatus of the present invention that achieves the above-described object
A core comprising a phase transition material that undergoes phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light, and a thermosetting coating the core. A toner image forming unit that forms a toner image using a toner having a shell mainly composed of a resin;
A transfer portion for transferring the toner image onto an image recording medium;
And a fixing unit that fixes the toner image on the image recording medium by irradiating the toner image on the image recording medium with light.

  According to the image forming apparatus of the present invention, the photo-heating material and the phase change material are contained in the toner core, so that the photo-heating material in the core generates heat when irradiated with light. As a result, the phase change material rapidly expands and destroys the toner shell, so that an image forming apparatus having high fixing performance can be formed.

In addition, a method for producing the toner of the present invention that achieves the above object includes:
A light-generating substance that generates heat upon receiving light, and is fixed on the image recording medium by being transferred to a desired image pattern on the image recording medium and heated to a predetermined fixing temperature, and between the room temperature and the fixing temperature. A method for producing a toner, comprising: a core containing a phase change material that undergoes phase transition with volume expansion at a predetermined temperature; and a shell mainly composed of a thermosetting resin that covers the core.
The substance constituting the core agent and an emulsifier aqueous solution having an acid catalyst function are mixed, and this mixed solution is emulsified to form an emulsion. The melamine resin initial polymer aqueous solution is added to the emulsion and stirred while heating. And the substance which comprises the said core agent is coat | covered with the formed melamine resin, It is characterized by the above-mentioned.

  According to the method for producing a toner of the present invention, the photo-heating substance and the phase change substance are contained in the toner core, so that the photo-heating substance in the core generates heat when irradiated with light. Because the heat generation causes the phase change material to rapidly expand and destroy the toner shell, a microcapsule toner having high fixing performance can be easily manufactured.

  As described above, according to the toner of the present invention, the photo-heating substance and the phase change substance are contained in the core, so that the photo-heating substance in the core generates heat when irradiated with light. The phase change material rapidly expands due to the heat generation and destroys the shell agent, so that high fixing performance can be obtained. In addition, since the core is coated with a shell mainly composed of a thermosetting resin, the heat resistance of the toner can be improved. For example, blocking or caking does not occur even in a high temperature environment.

  In addition, according to the image forming method of the present invention, the photogenic substance and the phase change substance are contained in the toner core, so that the photothermal substance in the core is heated by irradiation with light, Due to the heat generation, the phase change material rapidly expands and destroys the toner shell, so that fixing can be performed with high fixing performance.

  Further, according to the method for producing a toner of the present invention, the photogenic substance and the phase change substance are contained in the toner core, so that the photoexothermic substance in the core generates heat when irradiated with light. Since the heat generation causes the phase change material to rapidly expand and destroy the toner shell, a toner that can be fixed with high fixing performance can be easily manufactured.

  Embodiments of the present invention will be described below with reference to the drawings.

  The toner of the present invention is a toner that is transferred to a desired image pattern on an image recording medium such as paper and fixed by being heated to a predetermined fixing temperature, and is at a predetermined temperature between room temperature and the fixing temperature. It has a core containing a phase change material that undergoes phase transition accompanied by volume expansion and a light-generating material that generates heat upon receiving light, and a shell that covers the core and contains a thermosetting resin as a main component.

  FIG. 1 is an enlarged cross-sectional view of one embodiment of the toner of the present invention.

  As shown in FIG. 1, the toner 1 includes a colorant 2a, a light absorber 2b that absorbs light, and a phase transition that undergoes a phase transition at a predetermined temperature between room temperature and the toner fixing temperature. It is a capsule-structure toner having a core agent 2 containing a substance 2c and a shell agent 3 that covers the core agent 2 and is mainly composed of a thermosetting resin.

  The colorant 2a and the light absorber 2b correspond to an example of the light-generating substance referred to in the present invention.

  The toner 1 is designed so that the shell agent is destroyed by the increase in the internal pressure of the capsule due to the volume expansion accompanying the phase transition of the core agent 2 at the time of fixing by flash light irradiation. In this respect, the design philosophy is different from the microcapsule toner designed so that the shell agent itself is destroyed by the flash light irradiation as in the above-described conventional example.

  Therefore, the core agent 2 contains a phase change material that undergoes a phase expansion from a solid to a liquid, from a liquid to a gas, or from a solid to a gas with volume expansion at a predetermined temperature between room temperature and the toner fixing temperature. It is necessary to be unreasonable.

  As the phase change material 2c, it is preferable to use a material that causes rapid volume expansion at the time of phase transition, for example, a wax having a melting point of 100 ° C. or lower. Specifically, for example, petroleum wax such as paraffin wax, coal wax such as Fischer-Tropsch wax, mineral wax such as montan wax, animal and plant wax such as carnauba wax, beeswax and lanolin, polyolefin such as polyethylene and polypropylene Waxes and their modified products, long-chain aliphatic alcohols such as behenyl alcohol, pentaerythritol esters, dipentaerythritol esters, polyglycerin esters, sucrose esters and other fatty acid ester waxes, amide waxes and other waxes, and toluene, Examples thereof include solvents such as xylene, vegetable oil, and mineral oil, and crystalline organic substances such as hydrogenated bisphenol A, terpene compounds, and di-trimethylolpropane. Among these, the above waxes are more preferable from the viewpoint of safety and the like.

  Furthermore, the volume expansion coefficient from 25 ° C. to 150 ° C. of the phase change material 2c forming the core agent 2 is preferably 1.14 or more. In the experiments of the present inventors, even when the material expands by heating, if a material having a volume expansion coefficient from 25 ° C. to 150 ° C. of 1.14 or less is used as the core, Is known to be difficult to destroy.

  However, the numerical value of the volume expansion coefficient 1.14 is considered to be a value depending on the capsule particle diameter, the capsule film thickness, and the like. In the systems having different capsule particle diameters and capsule film thicknesses, the volume expansion coefficient is 1.14. Even if it is below, the effect of the present invention can be acquired.

  In addition, the core agent 2 needs to include a light heating material that absorbs the irradiated flash light and generates heat and imparts the heat to the phase change material 2c. The photo-exothermic substance is preferably a colorant or a light absorber, and more preferably an infrared absorber that absorbs infrared rays to generate heat or a heat ray absorber that generates heat by absorbing heat rays.

  A black pigment is suitable as the photothermal material. Since the black pigment has strong light absorptivity in a wide wavelength range extending from ultraviolet rays, visible rays, and infrared rays, it has a high ability to undergo phase transition of the core upon receiving flash light. However, since it also absorbs light in the visible light region, it is not preferable in the case of a color toner because it causes color turbidity.

  As the light absorber for the color toner, it is preferable to use an infrared absorbing material that has low light absorption in the visible light region and has light absorption in the main light emission region of xenon flash, 800 nm to 1000 nm.

  As the black colorant, black pigments such as carbon black, titanium black, ferrite, magnetite, and zirconium carbide can be used.

  As the colorant, a color dye or a color pigment can be used. For example, quinacridone (red), phthalocyanine (blue, etc.), anthraquinone (red), disazo (red or yellow), monoazo (red), anilide compound (yellow), pendidine (yellow), penzimidazolone (yellow), Halogenated phthalocyanine (green) or the like is used.

  Examples of infrared absorbing materials having light absorption at 800 nm to 1000 nm include, for example, aminium salts, indium oxide-based metal oxides, tin oxide-based metal oxides, zinc oxide-based metal oxides, cadmium stannate, specific amide compounds, Naphthalocyanine and / phthalocyanine compounds, cyanine compounds, lanthanoid compounds, black pigments such as carbon black, titanium black, ferrite, magnetite, and zirconium carbide are used. These can be used alone or in combination.

  Moreover, you may contain additives, such as a charge control agent, a dispersing agent, an offset prevention agent, in a core agent as needed.

  As the charge control agent, either a positive or negative charge control agent can be used. For example, nigrosine, a quaternary ammonium salt, a salicylic acid derivative, a boron compound, a metal-containing azo compound, calixarene, or the like can be used alone or in combination.

  As the thermosetting resin which is the main component of the shell agent 3, it is preferable to use a melamine resin. In the flash fixing method, it is expected that the outermost layer of the toner will be heated to several hundreds of degrees Celsius and the lower layer will be heated to several hundreds of degrees Celsius by flash light irradiation, but the melamine resin has high heat resistance, so the shell agent does not melt The shell agent is reliably destroyed by the pressure increase due to the expansion of the core agent, and the inner core agent can be exposed.

  Next, a method for producing the toner of the present invention will be described.

  The method for producing a toner of the present invention comprises a photo-heating substance that is transferred to a desired image pattern on an image recording medium and fixed on the image recording medium by being heated to a predetermined fixing temperature, and generates heat upon receiving light. A core containing a phase change material that undergoes phase transition at a predetermined temperature between room temperature and the fixing temperature, and a shell mainly composed of a thermosetting resin that covers the core. A method for producing a toner comprising mixing a substance constituting a core agent and an emulsifier aqueous solution having an acid catalyst function, and emulsifying the mixed solution to form an emulsion, and the melamine resin initial polymer aqueous solution is formed in the emulsion The material constituting the core is coated with a melamine resin shell formed by stirring while heating.

  As shown in FIG. 1, the toner 1 of the present invention is a toner having a capsule structure composed of a core agent 2 and a shell agent 3 covering the core agent 2. The encapsulation method for forming the toner of this capsule structure includes chemical methods such as interfacial polymerization method, in situ polymerization method, orifice method, physicochemical methods such as in-liquid drying method and method using phase separation, There are various methods such as a mechanical method such as a spray drying method and a method of forming a film from an ordered mixture, but any of these methods may be applied, and the method is not limited to a specific method.

  However, in the method for producing the toner of the present invention, from the viewpoint of compatibility between the core agent and the encapsulation method and the efficiency at the time of capsule formation, an appropriate strength is maintained in the normal state, and the internal pressure of the capsule is increased at the time of flash fixing. In particular, a method of producing a melamine resin shell by an in situ polymerization method is preferable in that a shell that can be easily broken is obtained.

  Specifically, a substance constituting the core agent and an aqueous emulsifier solution having an acid catalyst function are mixed, and this mixed solution is emulsified to form an O / W (oil / water) emulsion. A method of adding a melamine resin initial polymer aqueous solution adjusted to a predetermined pH to an emulsion, stirring while heating, and coating a core with a shell agent formed of the formed melamine resin to form a toner having a capsule structure. Most preferred.

  According to this production method, the core agent can be completely covered with the shell agent. Furthermore, melamine resin is also superior in terms of safety in that it does not generate harmful substances such as isocyanate even when it is thermally decomposed by irradiation with flash light.

  Next, an embodiment of a toner manufacturing method of the present invention will be described based on a flowchart.

  FIG. 2 is a flowchart showing an embodiment of the toner production method of the present invention.

  As shown in FIG. 2, a core material is prepared by mixing a photo-exothermic material (carbon or the like), a phase change material (wax or the like), and other additives as required (step S01), and heated (step After step S02), an aqueous emulsifier solution having an acid catalyst function is mixed with the heated one (step S03) (step S04), and the mixed solution is emulsified to form an emulsion whose particle size is adjusted (step S05). The particle size and particle size distribution of the core agent are determined by the processing conditions in this emulsification processing.

  By adding an aqueous solution of melamine resin initial polymer to the emulsion formed by the emulsification treatment and stirring while heating (step S06), a shell agent that covers the core with the polymerized melamine resin is formed. The thickness of the shell to be formed is determined by the heating condition and the stirring condition at this time. Thus, after covering the core with the melamine resin shell, washing (decantation) (step S07), further drying (step S08), and adding an external additive (step S09), the microcapsule toner is obtained. can get.

Examples of the toner production method of the present invention are shown below.
[Example 1]
85 parts by mass of paraffin wax (HNP-5: Nippon Seiwa) having a melting point of 62 ° C. and 15 parts by mass of carbon black (Regal 330R: Cabot) were mixed using a roll mill to obtain a core agent (A1).

  Furthermore, in 300 g of an aqueous solution of 5% styrene maleic anhydride alkaline hydrolyzate heated to 95 ° C., 200 g of the core agent (A1) dissolved by heating at 95 ° C. was added, emulsified with a homogenizer, and O / W An emulsion was prepared.

  Next, 60 grams of melamine-formaldehyde resin initial polymer in which 1 mole of melamine resin was dissolved in 3 moles of 37% formaldehyde aqueous solution adjusted to pH 8 to pH 9 with 10% aqueous sodium carbonate solution was added to the O / W emulsion. Stirring was continued at 80 ° C. for 2 hours to obtain microcapsule particles (dispersion) having an average particle diameter of 10 μm in which a melamine resin shell was formed on the surface and core agent A1 was encapsulated.

  Thereafter, decantation was repeated to wash the microcapsule particles, followed by drying. Furthermore, 1.4 parts by mass of hydrophobic silica (R972D: Nippon Aerosil) was added as an external additive to 100 parts by mass of the microcapsule particles after drying to obtain a microcapsule toner.

Furthermore, this microcapsule toner is spread on a sheet of paper using a mesh so as to have an adhesion amount of 5 g / m ² , and the flash fixing voltage (PS2160W: Fujitsu) is modified to change the flash irradiation voltage. Fixing was performed using a printer reduced by 30%. When a tape peeling test was performed to confirm the fixing strength, a good fixing property of 90% or more was confirmed.

  The tape peeling test was performed as follows. Adhesive tape (Scotch Mending Tape: Sumitomo 3M) was applied to the image surface, then the adhesive tape was peeled off at an angle of 90 °, the image density before and after peeling was measured, and the fixing rate was calculated from the following equation.

Fixing rate (%) = image density after peeling / image density before peeling × 100
In the above flash fixing, since the toner surface is instantaneously heated to several hundred degrees C., the paraffin wax having a melting point of 62 degrees C. undergoes complete phase transition between room temperature and fixing temperature, and rapidly expands the volume, thereby forming a shell agent. Is believed to have been destroyed.

The volume expansion coefficient from 25 ° C. to 150 ° C. of the core agent (A1) of this microcapsule toner was 1.20. In this microcapsule toner, carbon black acts as an infrared absorber.
[Example 2]
Roll mill with 85 parts by mass of ester wax (EW-440A RIKEN vitamin) having a melting point of 60 ° C., 15 parts by mass of carbon black (TS Black6P: Sinroihi), and 1 part by mass of charge control agent (Spilon Black TRH: Hodogaya Chemical Co., Ltd.) To obtain a core agent (A2).

  Furthermore, in 300 g of an aqueous solution of 5% styrene maleic anhydride alkaline hydrolyzate heated to 95 ° C., 200 g of the core agent (A2) dissolved at 95 ° C. by heating was added and emulsified with a homogenizer to obtain O / W. An emulsion was prepared.

  Next, 60 grams of melamine-formaldehyde resin initial polymer in which 1 mole of melamine resin was dissolved in 3 moles of 37% formaldehyde aqueous solution adjusted to pH 8 to pH 9 with 10% aqueous sodium carbonate solution was added to the O / W emulsion. Stirring was continued at 80 ° C. for 2 hours to obtain microcapsule particles (dispersion) having an average particle diameter of 10 μm in which a melamine resin shell was formed on the surface and core agent A2 was encapsulated.

  Thereafter, decantation was repeated to wash the microcapsule particles, followed by drying. Furthermore, 0.5 part by mass of hydrophobic silica (H3004: Clariant) was added as an external additive to 100 parts by mass of the microcapsule particles after drying to obtain a microcapsule toner.

  As in the first example, the microcapsule toner was subjected to a tape peeling test to confirm the fixing strength. As a result, good fixability of 90% or more was confirmed.

The volume expansion coefficient from 25 ° C. to 150 ° C. of the core agent (A2) of this microcapsule toner was 1.15.
Example 3
40 parts by mass of paraffin wax (115: Nippon Seiwa) having a melting point of 47 ° C., 45 parts by mass of ester wax (EW-440A: Riken Vitamin) having a melting point of 60 ° C., and 15 parts by mass of carbon black (Regal 330R / Cabot) Then, 1 part by mass of a charge control agent (Spilon Black TRH: Hodogaya Chemical Co., Ltd.) was mixed using a roll mill to obtain a core agent (A3).

  Furthermore, in 300 g of an aqueous solution of 5% styrene maleic anhydride alkaline hydrolyzate heated to 95 ° C., 200 g of the core agent (A3) dissolved at 95 ° C. was added and emulsified with a homogenizer to obtain O / W. An emulsion was prepared.

  Next, 60 grams of a melamine-formaldehyde resin initial polymer in which 1 mole of melamine resin is dissolved in 3 moles of 37% formaldehyde aqueous solution adjusted to pH 8 to pH 9 with 10% sodium carbonate aqueous solution is added to the O / W emulsion. Stirring was continued at 80 ° C. for 2 hours to obtain microcapsule particles (dispersion liquid) having an average particle size of 10 μm in which a melamine resin shell was formed on the surface and core agent A3 was encapsulated.

  Thereafter, decantation was repeated to wash the microcapsule particles, followed by drying. Furthermore, 0.5 part by mass of hydrophobic silica (H3004: Clariant) was added as an external additive to 100 parts by mass of the microcapsule particles after drying to obtain a microcapsule toner.

  As in the first example, the microcapsule toner was subjected to a tape peeling test to confirm the fixing strength. As a result, good fixability of 90% or more was confirmed.

The volume expansion coefficient from 25 ° C. to 150 ° C. of the core agent (A3) of this microcapsule toner was 1.23.
[Comparative Example 1]
85 parts by mass of silicon oil (SH200: Toray Dow Corning) and 15 parts by mass of carbon black (TS Black 6P: Sinloihi) were mixed using a rotor stator type emulsifier to obtain a core B1.

  Furthermore, 200 g of the core (B1) dissolved at 95 ° C. was added to 300 g of an aqueous solution of an alkaline hydrolyzate of 5% styrene maleic anhydride heated to 95 ° C., and emulsified with a homogenizer to obtain an O / W emulsion. Was prepared.

  Next, 60 grams of a melamine-formaldehyde resin initial polymer in which 1 mole of melamine resin was dissolved in 3 moles of 37% formaldehyde water bath adjusted to pH 8 to pH 9 with 10% aqueous sodium carbonate solution was added to the O / W emulsion. The mixture was continuously stirred at 80 ° C. for 2 hours to obtain microcapsule particles (dispersion) having an average particle size of 10 μm in which a melamine resin shell was formed on the surface and the core B1 was encapsulated.

  Thereafter, the same toner processing as in Example 1 was performed and a fixing test was performed. However, the fixing rate was only about 70%. Further, when the fixed image was observed with an SEM, the presence of many unbroken microcapsule toner particles was confirmed.

  The volume expansion coefficient from 25 ° C. to 150 ° C. of the core agent B1 was 1.12. The silicone oil used in this comparative example has a small volume expansion because it does not cause a phase transition between room temperature and the fixing temperature, the internal pressure of the capsule is not sufficiently high in the fixing portion, and many capsules that are not broken are generated. it is conceivable that.

  Next, an embodiment of the image forming apparatus of the present invention will be described.

  FIG. 3 is a schematic configuration diagram showing an embodiment of the image forming apparatus of the present invention.

  As shown in FIG. 3, the image forming apparatus 10 includes a photosensitive drum 11, a charger 12, an exposure unit 13, a developing unit 14, a photosensitive cleaner 15, a transfer unit 17, a flash fixing unit 18, and the like. The photosensitive drum 11, the charger 12, the exposure device 13, the developing device 14, and the photosensitive cleaner 15 correspond to an example of a toner image forming unit referred to in the present invention.

  Next, the operation of the image forming apparatus 10 will be described.

  The photosensitive drum 11 rotates in the direction of arrow A, and a uniform charge is applied to the surface by the charger 12. The charged image of the photosensitive drum 11 is irradiated with a light image from the exposure device 13 to form an electrostatic latent image on the photosensitive drum 11. The electrostatic latent image is developed with microcapsule toner housed in the developing device 14 to form a toner image T on the photosensitive drum 11. The toner image T on the photosensitive drum 11 is transferred by the transfer unit 17 to the image recording medium 16 conveyed in the direction of arrow B.

  The toner image T transferred onto the image recording medium 16 is irradiated with flash light from a xenon flash lamp 19 provided in the flash fixing unit 18.

  FIG. 4 is a diagram showing an example of an emission spectrum of a xenon flash lamp used for flash fixing.

  As shown in FIG. 4, the emission spectrum of this xenon flash lamp has a strong emission intensity in the near infrared region of 800 nm to 1000 nm.

  The toner image T on the image recording medium 16 is formed from the toner 1 (see FIG. 1) of the above-described embodiment, that is, the toner 1 having a capsule structure including the core agent 2 and the shell agent 3 covering the core agent 2. Therefore, the photo exothermic substance (colorant 2a and / or light absorber 2b) in the core agent 2 receives heat from the xenon flash lamp 19, and the phase in the core agent 2 is generated by the generated heat. When the transition material 2c undergoes phase transition and rapidly expands, the shell agent 3 mainly composed of a thermosetting resin that coats the core agent 2 is destroyed, and the photo-heating substance in the core agent 2 pops out to record an image. The image is fixed on the medium 16 to obtain a fixed image F.

  The toner remaining on the photosensitive drum 11 without being transferred to the image recording medium 16 in the transfer unit 17 is cleaned by the photosensitive member cleaner 15.

  In the present embodiment, the image formed of the photosensitive drum 11, the charger 12, the exposure device 13, the developing device 14, the photosensitive cleaner 15, the transfer unit 17, and the flash fixing unit 18 as shown in FIG. Although the image forming apparatus 10 has been described, the image forming apparatus of the present invention is not limited to this embodiment, and the volumetric expansion is performed at a predetermined temperature between the room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light. A toner image forming unit that forms a toner image using a toner that includes a core containing a phase change material that undergoes phase transition and a shell mainly composed of a thermosetting resin that covers the core. The present invention can be applied to all image forming apparatuses having the same. Further, it is also possible to apply to color image formation by using a color toner formed using a color coloring agent as a photo-heating substance.

FIG. 3 is an enlarged cross-sectional view of an embodiment of the toner of the present invention. 3 is a flowchart showing an embodiment of a toner manufacturing method of the present invention. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention. It is a figure which shows an example of the emission spectrum of the xenon flash lamp used for flash fixing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner 2 Core agent 2a Colorant 2b Light absorber 2c Phase change material 3 Shell agent 10 Image forming apparatus 11 Photoconductor drum 12 Charger 13 Exposure device 14 Developer 15 Photoconductor cleaner 16 Image recording medium 17 Transfer part 18 Flash fixing Part 19 Xenon flash lamp F Fixed image T Toner image

Claims (8)

In toner that is transferred onto an image recording medium and transferred to a desired image pattern and fixed by being heated to a predetermined fixing temperature,
A core comprising a phase change material that undergoes phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light;
A toner comprising a shell having a thermosetting resin as a main component and covering the core. The toner according to claim 1, wherein the photoheating substance is a colorant or a light absorber. The toner according to claim 1, wherein the light heating substance is an infrared absorber that generates heat by absorbing infrared rays or a heat ray absorber that generates heat by absorbing heat rays. The toner according to claim 1, wherein the thermosetting resin is a melamine resin. The toner according to claim 1, wherein the phase change material is a wax having a melting point of 100 ° C. or less. A core comprising a phase change material that undergoes phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light, and a thermosetting coating the core. A toner image is formed using a toner having a shell mainly composed of a resin,
Transferring the toner image onto an image recording medium;
An image forming method comprising fixing a toner image on the image recording medium by irradiating the toner image on the image recording medium with light. A core comprising a phase change material that undergoes phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, and a light heating material that generates heat upon receiving light, and a thermosetting coating the core. A toner image forming unit that forms a toner image using a toner having a shell mainly composed of a resin;
A transfer portion for transferring the toner image onto an image recording medium;
An image forming apparatus comprising: a fixing unit configured to fix the toner image on the image recording medium by irradiating the toner image on the image recording medium with light. A phase transition with volume expansion at a predetermined temperature between room temperature and the fixing temperature, which is transferred to a desired image pattern on the image recording medium and fixed on the image recording medium by heating to a predetermined fixing temperature. A toner comprising: a core comprising a phase change material and a light exothermic material that generates heat upon receipt of light; and a shell comprising a thermosetting resin as a main component and covering the core;
The substance constituting the core agent and an aqueous emulsifier solution having an acid catalyst function are mixed, the mixed solution is emulsified to form an emulsion, and the aqueous solution of the initial polymer of melamine resin is added to the emulsion, followed by stirring while heating. Then, a method for producing a toner, comprising coating the substance constituting the core with the formed melamine resin.

Images