JP4165355B2 - Transparent toner for electrophotography, transparent developer for electrophotography, and gloss imparting device - Google Patents

Description

  The present invention relates to a transparent toner for electrophotography for obtaining a good gloss image by transferring and fixing a color toner image such as a photographic image by electrophotography on which it is desired to impart gloss to the periphery thereof, and its transparent for electrophotography The present invention relates to a transparent developer for electrophotography containing toner, and a gloss imparting device using the transparent toner for electrophotography.

  Conventionally, in a color image forming apparatus for forming a color image by an electrophotographic method or an electrostatic recording method, a color image is formed on the surface of a recording medium. For example, when a color copy is made, the following image formation is performed. Process operations are performed.

  That is, the color original is illuminated, the reflected light image is color-separated and read by a color scanner, subjected to predetermined image processing and color correction by an image processing apparatus, and based on the obtained multiple-color image signals, for example, a semiconductor A laser or the like is modulated, and a laser beam modulated in accordance with an image signal is emitted from the semiconductor laser. By irradiating the surface of an organic photoreceptor using Se or amorphous silicon or an organic photoreceptor using a phthalocyanine pigment, a bisazo pigment or the like as a charge generation layer, a plurality of electrostatic latent images are formed. Form. Each of the plurality of electrostatic latent images formed on the surface of the inorganic or organic photoreceptor is sequentially treated with, for example, four color toners of yellow (Y), magenta (M), cyan (C), and black (K). develop. Then, the developed toner image is transferred from an inorganic or organic photosensitive member to the surface of a recording medium such as paper, and is heat-fixed by a fixing device including a heat fixing roll to form a color image on the surface of the recording medium. .

  Such a color image has a certain level of gloss because the surface is smoothed during heat fixing, whereas the surface of the paper usually does not have a gloss, and the color image It will have a different glossiness than the surface. In addition, it is known that the viscosity of the toner at the time of heat fixing changes due to the type of binder resin used for the color toner, the method of heat fixing, and the like, and the glossiness of the color image changes.

By the way, the preference for the glossiness of a color image varies depending on the type and purpose of use of the image and is various, but in the case of a photographic document such as a person or a landscape, generally, from the viewpoint of obtaining a clear image, High gloss images tend to be preferred.
As a technique for obtaining a highly glossy image in a color image forming apparatus, for example, the techniques described in Patent Documents 1 to 3 have been proposed. It is described that a highly glossy image can be obtained by selecting a material, fixing conditions, and the like.

  However, in the case of the techniques described in these documents, the glossiness of the image portion by toner can be increased, but the glossiness of the non-image portion cannot be increased, and the glossiness of the surface of the recording medium cannot be increased. There is a problem that it cannot be made uniform. Further, the unevenness of the color toner remains on the surface of the image and does not become smooth like a silver salt photograph or printing, so that there is a problem that a smooth texture cannot be obtained.

  Further, Patent Document 4 discloses that a recording medium on which a color toner image and a transparent toner image are formed is heated and melted by using a belt-type fixing device, and then cooled and peeled off, so that it has a high gloss like a silver salt photograph. An apparatus for forming the image is disclosed.

  However, in the case of this apparatus, a step is conspicuous at the boundary between the high concentration portion and the low concentration portion, and in particular, the low concentration small spot in the high concentration portion is recessed like a hole. Has a point. This phenomenon is caused by the fact that the binder resin in the transparent toner does not cause a flow necessary for filling the level difference of the color toner image, and becomes remarkable when the speed of the recording medium passing through the fixing device is high. . As long as the temperature and pressure conditions of the fixing device are used within a practical range, the technique described in the above document cannot solve both of a high printing speed and a high gloss and uniform image. Had.

  Further, the transparent toner used in the above technique has a problem that the transparent toner layer fixed by high temperature and high humidity environment or long-term storage is deformed, and further, the mechanical strength against bending is low, It also had the problem of being prone to cracking.

  In order to solve this problem, in order to produce a transparent toner with a practical production scale from a supple resin that has excellent low-temperature fixability and is difficult to break, a submerged drying method, emulsion aggregation method, melt suspension method, dissolution It seems appropriate to use a wet method such as a suspension method. However, in the in-liquid drying method and the dissolution suspension method using an organic solvent, the materials that can be used are often limited by the combination of the solubility in an aqueous layer and an oil layer and the usable solvent. There is a concern that it itself becomes a manufacturing issue from the viewpoint of environmental load and safety.

  In the emulsion aggregation method and melt suspension method in which dispersion and emulsification are carried out in an aqueous system, it is necessary to introduce hydrophilicity into the polymer molecular structure and to use a surfactant in order to obtain dispersion stability. However, when a toner is produced using a material in which a polyester resin is imparted with a degree of hydrophilicity necessary for emulsification, the chargeability and environmental stability of the resulting toner may be impaired. For this reason, it is preferable to supplement the hydrophilicity with a surfactant or the like, but there is a concern that the use of a large amount of the surfactant becomes a manufacturing problem from the viewpoint of environmental load and cleaning cost.

JP-A-5-142963 JP-A-3-2765 JP-A 63-259575 JP-A-5-158364

  Therefore, the present invention solves the above-described conventional problems, and can obtain a high-quality silver-salt photographic image with a sufficiently small difference in the toner image finally obtained by high-speed and low-temperature fixing, and excellent gloss. , A transparent toner for electrophotography that does not cause image damage such as offset or crack due to temperature and humidity changes during storage, and is excellent in wet manufacturability, a transparent developer for electrophotography including the transparent toner for electrophotography, and the above An object of the present invention is to provide a gloss imparting device using a transparent toner for electrophotography.

  The present inventors eliminate the step between the surface of the recording medium and the color toner image by forming a transparent toner image made of a binder resin having specific properties on the color toner image formed on the recording medium. It has been found that a high-quality image of a salt photographic tone can be obtained, and further image quality deterioration such as offset and cracks due to the influence of temperature and humidity during long-term storage can be suppressed, and the present invention has been completed. That is, the present invention is as listed below.

<1> Transparency for forming a color toner image on the surface of a recording medium by electrophotography using a color toner containing at least a thermoplastic resin and a colorant, and then transferring and fixing it on or around the color toner image Toner,
The aromatic component as an acid-derived constituent component is 90 mol% or more with respect to the total acid-derived constituent component, and the linear aliphatic diol as the alcohol-derived constituent component is 85 to 98 mol% with respect to the total alcohol-derived constituent component. The crystalline polyester resin included in the range includes 70% by mass or more of the total binder resin component as a binder resin,
When a film having a thickness of 20 μm is obtained from the polyester resin, the luminous reflectance Y of the film is 1.5% or less, and
The transparent toner for electrophotography, wherein the polyester resin contains bisphenol S or a bisphenol S alkylene oxide adduct in a range of 2 to 15 mol% with respect to all alcohol-derived components.

  <2> The transparent toner for electrophotography according to <1>, wherein the linear aliphatic diol as the alcohol-derived constituent component in the polyester resin is a linear aliphatic diol having 6 to 12 carbon atoms. is there.

  <3> The aromatic component derived from at least one compound selected from the group consisting of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid as a main component is an acid-derived constituent component in the polyester resin. The electrophotographic transparent toner according to <1> or <2>, wherein

  <4> The electrophotographic transparent toner according to any one of <1> to <3>, wherein the polyester resin has a mass average molecular weight in the range of 12,000 to 50,000.

<5> When the melting point of the binder resin is Tm and the temperature at which the viscosity of the thermoplastic resin contained in the color toner is 10 ⁴ Pa · s is Tm ′, the following formula (1) is satisfied: The transparent toner for electrophotography according to any one of <1> to <4>.
Tm ≦ Tm ′ ≦ Tm + 25 ° C. Formula (1)

  <6> After forming a color toner image on the surface of the recording medium by an electrophotographic method using a color toner comprising a carrier and a transparent toner and containing at least a thermoplastic resin and a colorant, the color toner image is formed on or over the color toner image. A transparent developer for electrophotography used for transferring and fixing the transparent toner around the transparent toner, wherein the transparent toner is the transparent toner for electrophotography according to any one of <1> to <5>. And a transparent developer for electrophotography.

<7> A color toner image is formed on the surface of a recording medium by electrophotography using a color toner containing at least a thermoplastic resin and a colorant, and then a transparent toner is transferred and fixed on or around the color toner image. A gloss imparting device for imparting gloss to an image,
A transparent toner image carrier for carrying a transparent toner image comprising the transparent toner;
A transparent toner image forming means for forming the transparent toner image on the surface of the transparent toner image carrier;
The transparent toner image formed on the surface of the transparent toner image carrier is transferred onto the surface of the recording medium on which the color toner image is formed, and is heated and pressed to be heated and heated for fixing. Pressure means;
Cooling and peeling for cooling the transparent toner image and color toner image transferred and fixed on the surface of the recording medium and then peeling the recording medium on which the transparent toner image and color toner image are formed from the transparent toner image carrier. Means,
And comprising
The gloss imparting apparatus according to any one of <1> to <5>, wherein the electrophotographic transparent toner according to any one of <1> to <5> is used as the transparent toner.

  <8> The gloss imparting apparatus according to <7>, wherein the color toner image on the surface of the recording medium provided to the heating and pressing unit is an unfixed color toner image.

  <9> The gloss applying apparatus according to <7>, wherein the color toner image on the surface of the recording medium, which is provided to the heating and pressing unit, is previously melt-fixed.

  According to the present invention, high-quality images with excellent gloss can be obtained even at high-speed and low-temperature fixing, and image damage such as offset and cracks due to changes in temperature and humidity during storage does not occur. An excellent electrophotographic transparent toner, an electrophotographic transparent developer containing the electrophotographic transparent toner, and a gloss imparting apparatus using the electrophotographic transparent toner can be provided.

  Hereinafter, the transparent toner for electrophotography of the present invention will be described in detail below, and then the transparent developer for electrophotography of the present invention and the gloss imparting apparatus of the present invention will be referred to in order.

[Transparent toner for electrophotography]
The transparent toner for electrophotography of the present invention (hereinafter sometimes simply referred to as “transparent toner of the present invention”) uses a color toner containing at least a thermoplastic resin and a colorant, and forms a color toner image by electrophotography. A transparent toner for transferring and fixing on or around the color toner image after being formed on the surface of the recording medium,
The aromatic component as an acid-derived constituent component is 90 mol% or more with respect to the total acid-derived constituent component, and the linear aliphatic diol as the alcohol-derived constituent component is 85 to 98 mol% with respect to the total alcohol-derived constituent component. The crystalline polyester resin included in the range includes 70% by mass or more of the total binder resin component as a binder resin,
When a film having a thickness of 20 μm is obtained from the polyester resin, the luminous reflectance Y of the film is 1.5% or less, and
The polyester resin contains bisphenol S or a bisphenol S alkylene oxide adduct in a range of 2 to 15 mol% with respect to all alcohol-derived components.

  The components contained in the transparent toner of the present invention are roughly divided into a binder resin and other components. Hereinafter, the binder resin and other components will be described separately, and further, physical properties as a toner, a manufacturing method thereof, and other elements that define the transparent toner of the present invention will be described.

<Binder resin>
The binder resin used in the transparent toner of the present invention contains 70% by mass or more of a crystalline polyester resin based on the total binder resin component. The ratio of the polyester resin to the total binder resin component is more preferably 80% by mass or more, further preferably 90% by mass or more, and particularly preferably all of the polyester resin is a crystalline polyester resin.

In the case of a polymer obtained by copolymerizing another component with the polyester resin main chain, if the other component (third component) is 50 mol% or less, in the present invention, this copolymer is also a crystalline polyester resin. It is also possible to copolymerize an appropriate third component as necessary, for example, for adjusting the melting point. The copolymerization ratio of these other components is preferably 12.5 mol% or less, and more preferably 2 mol% or less.

  In the present invention, since the crystalline polyester resin mainly constituting the binder resin has a crystal structure in the molecular chain, it is possible to lose the crystallinity by applying a constant thermal energy to the crystal part and to make it flow at once. it can. By using the characteristics of the crystalline polyester resin, the temperature range from the storable temperature range to the fixing temperature range can be narrowed, and both the decrease in melt viscosity and the improvement in the heat resistance temperature can be achieved. However, when a transparent toner layer is formed with a general crystalline polyester resin alone, the clearness of the image is impaired due to white turbidity due to the fine crystal structure, and in the long term, the slow crystallization progresses. Causes embrittlement and gloss fluctuation.

  Therefore, in the present invention, bisphenol S is introduced into the crystalline polyester resin molecule, and the crystal dispersion unit is made small so that crystallization proceeds faster after fixing. As a result, the transparent toner of the present invention can suppress the progress of crystallization over a long period of time, and can satisfy the fluidity, the low-temperature fixability, and the heat-resistant storage stability at a high level.

  In order to introduce bisphenol S into the polyester resin molecule, in the present invention, bisphenol S itself or a bisphenol S alkylene oxide adduct is contained in a range of 2 to 15 mol% with respect to all alcohol-derived components. The content is preferably in the range of 5 to 10 mol%. When the content is less than 2 mol%, the luminous reflectance Y described later hardly satisfies the provisions of the present invention, and the image clarity is impaired due to white turbidity due to the crystal structure. In the long term, embrittlement and gloss fluctuation due to slow crystallization progress. On the other hand, if the content exceeds 15 mol%, plasticization of the resin occurs and heat resistance is impaired.

As described above, as one of the purposes of incorporating bisphenol S or a bisphenol S alkylene oxide adduct (hereinafter sometimes simply referred to as “bisphenol S etc.”) into the crystalline polyester resin, the crystal dispersion unit is made small and transparent. It is mentioned that it is going to improve the transparency as a toner. Therefore, the amount of the bisphenol S or the like to be added is such that the amount of the luminous reflectance Y is 1.5% or less. If the luminous reflectance Y exceeds 1.5%, solidification of the binder resin is slowed, the surface of the image is difficult to be smooth, gloss unevenness occurs, and peeling cannot occur after fixing. The luminous reflectance Y is preferably 1.5% or less and lower, that is, more transparent.

(Luminous reflectance Y)
Here, the luminous reflectance Y will be described.
The luminous reflectance Y in the present invention refers to the luminous reflectance of the film when a film having a thickness of 20 μm is obtained from the polyester resin to be measured. More specifically, it is as follows.

  First, a film (preferably a thickness of 20 μm) is formed from a polyester resin (hereinafter, the obtained film may be referred to as “resin film”). And in order to remove the scattering component of the surface and back surface, the said resin film is pinched | interposed with the transparent cover glass for microscope observation, and a refractive index matching liquid (tetradecane) is satisfy | filled between glass and a resin film. The sample is subjected to reflection measurement on a light and a lap with a colorimeter that satisfies the geometric colorimetric condition of 0/45 degrees (for example, X-rire968, manufactured by X-rire). The Y value measured in this way in the CIE XYZ color system coincides with the luminous reflectance Y. When the film to be measured is transparent and the cover glass is also transparent, Y is almost zero. That is, the value of Y corresponds to the intensity of the scattering component inside the resin film.

  When a polyester resin not containing or lacking a third component such as bisphenol S is used as a measurement target, the scattering intensity due to resin crystal dispersion is strong, and the value of luminous reflectance Y increases. On the other hand, the smaller the crystal dispersion of the polyester resin is, the smaller the value of the luminous reflectance Y becomes. Therefore, the luminous reflectance Y is an index of the crystal dispersion size.

  Of course, the thickness of the resin film used for measurement is preferably 20 μm, but when the scattering is 2% or less, the value of luminous reflectance Y is almost proportional to the thickness of the resin film. Even if the thickness is not exactly 20 μm, the luminous reflectance Y may be calculated in terms of the thickness.

  The method for producing the resin film used for the measurement is not particularly limited as long as the purpose of forming a film having a uniform and uniform thickness is not impaired. For example, place a base material with a smooth top surface and good releasability on a top plate such as a hot plate, dissolve the polyester resin to be measured on this base material, and apply it with Erichsen or a bar coater. By the method of peeling the film from the substrate, the resin film used for measurement can be obtained.

In addition, a film made on a suitable base material is layered on a transparent film such as a PET film, heated and pressurized, peeled off the base material, and transferred to another transparent film as a sample. Y may be measured. In this case, the luminous reflectance Y of the resin film to be measured can be calculated by subtracting the reflectance Y ₀ of the other transparent film itself from the measured luminous reflectance Y _{t of the} sample.

  In general, a polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the following description, in the polyester resin, the component that was an acid component before the synthesis of the polyester resin is referred to as “acid-derived component”, and the component that was the alcohol component before the synthesis of the polyester resin is referred to as “alcohol. "Derived component".

  The polyester resin used in the present invention improves the flexibility (flexibility) of the resin and improves the mechanical strength against bending with respect to the linear alcohol diol as the alcohol-derived constituent component with respect to all the alcohol-derived constituent components. It is required to be contained in the range of 85 to 98 mol%, preferably in the range of 90 to 98 mol%, and more preferably in the range of 95 to 98 mol%. When the linear aliphatic diol is less than 90 mol%, the flexibility due to the introduction of the structure derived from the linear aliphatic becomes insufficient, and the effect of improving the mechanical strength against bending is reduced. On the other hand, if it exceeds 98 mol%, the effect of reducing the crystalline dispersion unit is weakened, the clarity of the image is impaired due to white turbidity due to the crystal structure, and in the long term, the progress of slow crystallization Causes embrittlement and gloss fluctuation.

As alcohol for becoming the said alcohol-derived structural component, a C6-C12 aliphatic diol is preferable.
Specific examples of the aliphatic diol include 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1, Although 11-undecanediol, 1,12-dodecanediol, etc. are mentioned, it is not limited to these. Among these, from the viewpoints of fixing property and heat resistance, a linear aliphatic diol having 6 to 12 carbon atoms is preferable, and considering availability, 1,8-octanediol, 1,9-nonanediol, 1, 10-decanediol is preferred, and 1,9-nonanediol is particularly preferred because of its low melting point.

  The polyester resin used in the present invention is required to contain 90 mol% or more of an aromatic component as an acid-derived component with respect to the total acid-derived component, preferably 95 mol% or more, and more preferably 98 mol% or more. preferable. When the aromatic component is less than 90 mol%, the melt mixing property, opportunity strength, and heat resistance are deteriorated.

  Examples of the aromatic component for becoming the acid-derived constituent component include various aromatic dicarboxylic acids. For example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like, or lower alkyl esters and acid anhydrides thereof can be mentioned, but are not limited thereto. Absent. Among these, it is preferable that the main component is an aromatic derived from at least one compound selected from the group consisting of terephthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4′-biphenyldicarboxylic acid. Terephthalic acid is most preferable in view of the properties and the ease of forming a low melting point polymer.

Moreover, as an acid-derived constituent component of the polyester resin, an aromatic component can be 90 mol% or more, and an aliphatic dicarboxylic acid can be used as another acid-derived constituent component. For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof And acid anhydrides may be mentioned, but the invention is not limited thereto.
Among these, considering availability, sebacic acid and 1,10-decanedicarboxylic acid are preferable.

  The mass average molecular weight of the polyester resin that mainly constitutes the binder resin is preferably in the range of 12,000 to 50,000, more preferably in the range of 17000 to 40000. When the mass average molecular weight is less than 12,000, the mechanical strength is weakened and it is easy to break. On the other hand, when the mass average molecular weight exceeds 50000, the fluidity is deteriorated and a smooth image may not be obtained.

As melting | fusing point of the polyester resin which mainly comprises the said binder resin, it is preferable that it is the range of 80-110 degreeC, It is more preferable that it is the range of 80-100 degreeC, It is the range of 85-95 degreeC. Further preferred.
When the melting point is less than 80 ° C., powder aggregation tends to occur and the storability of a fixed image may be deteriorated. On the other hand, when it exceeds 110 ° C., low-temperature fixing may be difficult.

  In the present invention, the melting point of the polyester resin is measured by using a differential scanning calorimeter (DSC), and the top value of the endothermic peak when measured at a temperature rising rate of 10 ° C./min from room temperature to 150 ° C. Was used.

In the present invention, the presence or absence of crystallinity was determined using differential scanning calorimetry (DSC). Specifically, as a result obtained by the apparatus, it is not a stepwise endothermic change, but has one or more distinct endothermic peaks, and 10 ² Pa · S or more in the range of the peak temperature ± 10 ° C. If a change in viscosity is confirmed, the resin is judged to have crystallinity. In addition, the endothermic peak is treated as an endotherm derived from crystals, and the peak temperature is treated as the melting point (Tm) of the (crystalline) polyester resin.

  There is no restriction | limiting in particular as a manufacturing method of the said polyester resin, It can manufacture with the polymerization method of the general polyester resin which makes an acid component and an alcohol component react. That is, an oligomer can be obtained by esterifying or transesterifying a dibasic acid and a dihydric alcohol, and then synthesized by performing a polycondensation reaction under vacuum. Further, as described in JP-B-53-37920, it can also be synthesized by a depolymerization method of a polyester resin.

  As the dibasic acid, a transesterification reaction is performed using at least one of an alkyl ester of a dicarboxylic acid such as dimethyl terephthalate, and then a polycondensation reaction is performed. You may react. However, since the melting point of bisphenol S alkylene oxide is high, for example, a dibasic acid and a dihydric alcohol are reacted at 180 to 200 ° C. under atmospheric pressure for 2 to 5 hours, and the distillation of water or alcohol is terminated. Complete the transesterification reaction. Next, the pressure in the reaction system is set to a high vacuum of 1 mmHg or less, the temperature is raised to 200 to 230 ° C., and the polyester resin can be obtained by heating at this temperature for 1 to 3 hours.

  As described above, the binder resin used in the transparent toner of the present invention contains the above polyester resin in an amount of 70% by mass or more of the total binder resin component. As the remaining resin, for example, for the purpose of accelerating solidification after fixing, a polyester resin having the same component as the polyester of the present invention but having a different composition may be mixed. Further, for the purpose of increasing the affinity with the color toner, a binder resin for the color toner may be mixed. However, these additive resins and the binder resin used in the transparent toner of the present invention need to have an affinity that does not cause phase separation. When phase separation of the resin component occurs, the binder resin becomes cloudy, resulting in a loss of image clarity.

When the temperature at which the viscosity of the thermoplastic resin contained in the color toner of the color toner image formed on the recording medium where high gloss of the image is desired is 10 ⁴ Pa · s is Tm ′, the following formula (1) is obtained. It is preferable to satisfy.
Tm ≦ Tm ′ ≦ Tm + 25 ° C. Formula (1)

That is, in the transparent toner of the present invention, the melting point Tm ′ of the binder resin to be used is a temperature at which the thermoplastic resin in the color toner image to be highly glossed is softened (a temperature at which the viscosity is 10 ⁴ Pa · s). ) Tm or more is preferable, but it is not preferable if the temperature difference is too large (25 ° C or more). If Tm ′ is lower than Tm, there is a concern that the color toner image is disturbed in the middle density portion and the graininess is deteriorated, the line is thickened or the characters are crushed. If the temperature is higher than Tm by 25 ° C., bubbles are generated in the vicinity of the image edge at the boundary between the high density solid image portion where the development amount of the color toner image is large and the non-image portion where there is no color toner image. There are problems, which are undesirable.
As the relationship between Tm and Tm ′, it is more preferable to satisfy the following formula (2).
Tm ≦ Tm ′ ≦ Tm + 20 ° C. Formula (2)

  The polyester resin used for the binder resin of the transparent toner of the present invention may be one kind or a mixture of a plurality of different polyester resins on condition that various requirements specified in the present invention are satisfied.

<Other ingredients>
The transparent toner of the present invention contains the binder resin as an essential component, but other components that can be used for conventionally known general transparent toners can also be used as appropriate. There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, well-known various additives, such as inorganic fine particles, organic fine particles, a charge control agent, a mold release agent, etc. are mentioned.

  The inorganic fine particles are generally used for the purpose of improving toner fluidity. Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride. , Bengara, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride and the like. Among these, silica fine particles are preferable, and silica fine particles that have been hydrophobized are particularly preferable.

  The average primary particle size (number average particle size) of the inorganic fine particles is preferably 1 to 1000 nm, and the addition amount (external addition) is 0.01 to 20 parts by mass with respect to 100 parts by mass of the transparent toner. Is preferred.

  The organic fine particles are generally used for the purpose of improving cleaning properties and transferability. Examples of the organic fine particles include fine particles such as polystyrene, polymethyl methacrylate, and polyvinylidene fluoride.

The charge control agent is generally used for the purpose of improving chargeability. Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts.
The release agent is generally used for the purpose of improving release properties. Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Mineral / petroleum waxes; ester waxes such as fatty acid esters, montanic acid esters, and carboxylic acid esters. In this invention, these mold release agents may be used individually by 1 type, and may use 2 or more types together.

  The addition amount of these release agents is preferably 0.5 to 50% by weight, more preferably 1 to 30% by weight, and still more preferably 5 to 15% by weight with respect to the total amount of the transparent toner. . When the amount is less than 0.5% by weight, there is no effect of adding a release agent. When the amount is 50% by weight or more, the chargeability is likely to appear, or the toner is easily destroyed inside the developing machine. As a result, the carrier tends to be spent, and the charge tends to decrease, and the surface of the image during leaching tends to be insufficient, and the release agent tends to stay in the image. Therefore, transparency is deteriorated, which is not preferable.

The surface of the transparent toner of the present invention may be covered with a surface layer. It is desirable that the surface layer does not greatly affect the mechanical properties and melt viscoelastic properties of the entire toner. For example, if the surface layer of non-melting or high melting point covers the toner thickly, the low-temperature fixability due to the use of the crystalline polyester resin cannot be sufficiently exhibited.
Therefore, it is desirable that the thickness of the surface layer is thin, and specifically, it is preferable to be within a range of 0.001 to 0.5 μm.

In order to form a thin surface layer in the above range, a method of chemically treating the surface of particles containing binder resin, colorant, inorganic fine particles added as necessary, and other materials is preferable. used.
Examples of the component constituting the surface layer include silane coupling agents, isocyanates, vinyl monomers, and the like, and it is preferable that a polar group is introduced into the component, and it is chemically bonded. As a result, the adhesive force between the toner and the transfer medium such as paper increases.

  The polar group may be any polar functional group, for example, carboxyl group, carbonyl group, epoxy group, ether group, hydroxyl group, amino group, imino group, cyano group, amide group, imide group , Ester groups, sulfone groups and the like.

  Examples of the chemical treatment method include a strong oxidizing substance such as a peroxide, a method of oxidizing by ozone oxidation, plasma oxidation or the like, a method of bonding a polymerizable monomer containing a polar group by graft polymerization, and the like. By the chemical treatment, the polar group is firmly bonded to the molecular chain of the crystalline resin through a covalent bond.

  In the present invention, a chargeable substance may be chemically or physically attached to the toner particle surface. Further, fine particles such as metal, metal oxide, metal salt, ceramic, resin, and carbon black may be externally added for the purpose of improving charging property, conductivity, powder fluidity, lubricity and the like.

<Physical properties as toner>
In the transparent toner of the present invention, the temperature Tm ″ at which the viscosity of the transparent toner as a whole is 10 ³ Pa · s is preferably in the range of 80 to 110 ° C. The temperature Tm ″ is less than 80 ° C. In some cases, the heat resistance may not be sufficient, and if left at high temperatures, problems such as blocking may occur. On the other hand, when the temperature Tm ″ exceeds 110 ° C., it may be difficult to obtain a smooth and glossy image surface by fixing. In particular, in the fixed image surface, a high density portion and a low density portion are obtained. A step may remain at the boundary.

The volume average particle diameter of the transparent toner of the present invention is preferably in the range of 6.0 to 16.0 μm, and more preferably in the range of 12.0 to 16.0 μm. If necessary, the particle size distribution may be sharpened through a classification process using an air classifier or the like.
The volume average particle diameter can be measured with an aperture diameter of 50 μm using, for example, a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement is performed after the toner to be measured is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

<Method for Producing Toner of the Present Invention>
As the method for producing the transparent toner of the present invention described above, it is preferable to adopt a wet production method because pulverization is difficult. The production method that can be employed is not particularly limited, and can be appropriately selected from known wet production methods such as a submerged drying method, an emulsion aggregation method, a melt suspension method, and a dissolution suspension method. Among these, from the viewpoint of environmental impact and safety, the melt suspension method and emulsion aggregation method that do not use organic solvents are preferable. From the functional viewpoint of transparent toner that laminates a color toner image, the development amount / development rather than the resolution. Since the agent fluidity and chargeability are important, the melt suspension method is more preferable than the emulsion aggregation method, because a larger particle size can be easily obtained.

  In order to obtain suspended and emulsified particles of polyester resin in an aqueous system without using a solvent in a practical yield, an ionic hydrophilic group derived from, for example, sulfonic acid is introduced or dispersed in the polyester resin molecular structure. It is necessary to use a large amount of an auxiliary agent or a surfactant, and there are cases where problems remain in chargeability and environmental stability when the toner is formed.

  Since the polyester resin used in the transparent toner of the present invention contains a hydrophilic group derived from bisphenol S, it has a high affinity for water and can reduce the amount of dispersion aid used. Further, since the hydrophilic group is nonionic, the environmental stability of the toner is high, which is advantageous for employing the melt suspension method.

Hereinafter, as an example of a method for producing the transparent toner of the present invention, a production method by a melt suspension method will be described.
In the melt suspension method, a polymer suspension containing a polyester resin as a main component is dispersed and suspended in an aqueous dispersion medium using an emulsifier having rotating blades to prepare a dispersion suspension in which particles are formed. It has at least a turbid process.

In such a dispersion suspension step, the polymer is dispersed in an aqueous dispersion medium using a disperser, and heated to lower the viscosity of the polymer to give a shearing force. ) Examples of the disperser include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser.
From the obtained dispersion liquid of dispersed particles, the dispersed particles are separated by the solid-liquid separation process such as filtration, and toner particles are produced through a washing process and a drying process as necessary.

  In the dispersion suspension step, a dispersant may be used for stabilizing the suspension and increasing the viscosity of the aqueous dispersion medium. Examples of the dispersant that can be used include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate.

Next, as another example of the method for producing the transparent toner of the present invention, a production method by an emulsion aggregation method will be described.
The emulsion aggregation method includes at least an emulsification step of emulsifying a specific polyester resin to form emulsion particles, an aggregation step of forming aggregates of the emulsion particles, and a fusion step of thermally fusing the aggregates. Have.

  The emulsified particles in the emulsification step can be prepared by dispersion suspension using a solvent, but it is preferable to prepare the emulsified particles in water without substantially using a solvent. As the size of the emulsified particles, the average particle size (volume average particle size) is preferably in the range of 0.01 to 1 μm, more preferably in the range of 0.03 to 0.6 μm, and 0.03 to 0.4 μm. The range of is more preferable.

  In the emulsification step, a dispersant may be used for stabilizing the emulsified particles. Examples of the dispersant that can be used include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium octadecyl sulfate, sodium oleate, sodium laurate, and potassium stearate; laurylamine acetate, stearylamine acetate, lauryltrimethylammonium Cationic surfactants such as chloride; Zwitterionic surfactants such as lauryl dimethylamine oxide; Nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl amine; Phosphoric acid Inorganic salts such as tricalcium, aluminum hydroxide, calcium sulfate, calcium carbonate, and barium carbonate can be used.

  In the aggregation step, the obtained emulsified particles are heated and aggregated at a temperature just before the melting point of the polyester resin to form an aggregate. Formation of the aggregates of the emulsified particles is performed by acidifying the pH of the emulsion under stirring. As the said pH, the range of 2-6 is preferable, The range of 2.5-5 is more preferable, The range of 2.5-4 is further more preferable.

  In the formation of the aggregate of the emulsified particles, it is also effective to use a flocculant. As the flocculant usable here, a surfactant having a polarity opposite to that of the surfactant used in the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

In the fusion step, under the same agitation as in the aggregation step, the aggregation suspension is stopped by setting the pH of the suspension of the aggregate to a range of 3 to 7, at a temperature equal to or higher than the melting point of the polyester resin. The aggregates are fused by heating. As heating temperature at this time, if it is more than melting | fusing point of the said polyester resin, there is no problem. Moreover, as a heating time at this time, it should just be performed to the extent that fusion is fully made, and what is necessary is just to carry out about 0.5 to 10 hours. In this way, a dispersion liquid in which the fused particles are dispersed is obtained.
The fusion particle dispersion obtained in the fusion step is separated into solid particles by a solid-liquid separation step such as filtration, and toner particles are produced through a washing step and a drying step as necessary.

  In the case of the emulsion aggregation method described above, the crosslinking step may be introduced after the aggregation step, the fusion step or the fusion step. When the crosslinking step is introduced after the aggregation step, the fusion step or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a particle dispersion (resin particle dispersion or the like). For the purpose of controlling the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like may be added to the polymerization initiator. The polymerization initiator may be mixed with the polymer in advance before the emulsification step, or may be incorporated into the aggregate in the aggregation step.

Next, as another example of the method for producing the transparent toner of the present invention, a production method by a dissolution suspension method will be described.
The dissolution suspension method includes a mixing step of preparing a mixed solution by dissolving or dispersing at least a binder resin mainly composed of a polyester resin, a charge control agent, and the like in a solvent, and the mixed solution as an aqueous medium. Dispersion suspension step of preparing a dispersion suspension in which particles are formed by dispersing and suspending using an emulsifier having a rotating blade, and removing the solvent from the obtained dispersion suspension Process.

In the mixing step, a binder resin containing a polyester resin as a main component, a charge control agent, and other resins and monomers as necessary are dissolved in a solvent to obtain a mixed solution (polymer solution).
Examples of the solvent that can be used here include alcohols such as methanol, ethanol, propanol, and butanol; polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol; cellosolves such as methyl cellosolve and ethyl cellosolve. , Ketones such as acetone, methyl ethyl ketone and ethyl acetate; ethers such as tetrahydrofuran; hydrocarbons such as benzene, toluene and hexane; or water. The solvent is appropriately selected and used depending on the type of polyester resin used as the binder resin and other monomers used as necessary and the particle size. These can be used alone or in admixture of two or more.

As the usage-amount of the said solvent, the range of 50-5,000 mass parts is preferable with respect to 100 mass parts of total amounts of a polyester resin and the other monomer added as needed, The range of 120-1,000 mass parts Is more preferable.
Subsequently, in the dispersion suspension step, a suspension of the polyester resin (dispersion of suspended particles) is applied to the solution obtained by mixing the mixed solution (polymer solution) and the aqueous medium using a disperser. Liquid). At that time, by heating, the viscosity of the polymer liquid can be lowered to form particles. Examples of the disperser include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser.

The obtained dispersion of suspended particles is separated by the solid-liquid separation process such as filtration, and then, if necessary, toner particles are produced through a washing process and a drying process.
In the dispersion step, the same dispersant as in the melt suspension method or the emulsion aggregation method may be used for stabilizing the suspension and increasing the viscosity of the aqueous medium.

Further, a cross-linking step may be introduced in which the dispersion liquid of the suspended particles of the polyester resin is heated and the cross-linked structure is introduced into the particles by a radical reaction as long as the fluidity is not impaired. As such a crosslinking process, the polyester resin obtained by dissolving the polymerization initiator in the aqueous medium (or the total binder resin containing it) were suspended and dispersed, heat the polymerization, or polyester resin (or it For example , a polymerization initiator is added later, and then polymerization is performed.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di- t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'- Azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethyl Cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxy) Carbonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylper) Oxycyclohexyl) propane, di-t-butylperoxy-α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydride Loterephthalate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butyl Peroxytrimethyladipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2′-azobis (2-methylpropionamidine dihydrochloride), 2,2′-azobis [N -(2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

  These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the polymer.

<Other Elements for Defining Transparent Toner of the Present Invention>
The transparent toner of the present invention uses a color toner containing at least a thermoplastic resin and a colorant, forms a color toner image on the surface of a recording medium by electrophotography, and then transfers and fixes it on or around the color toner image. It is premised on that it is for.

The color toner is not particularly limited as long as it is a general color toner containing at least a thermoplastic resin and a colorant. As for the additive components other than the thermoplastic resin and the colorant, those similar to <other components> in the transparent toner of the present invention can be internally or externally added.
The thermoplastic resin is not particularly limited, and a conventionally known resin can be used. Specific examples include polyester resins, styrene / acrylic copolymers, styrene / butadiene copolymers, and the like.

  The colorant is not particularly limited, and a conventionally known colorant can be used. For example, benzidine yellow, quinoline yellow, hansa yellow, etc. as yellow (Y) colorants; rhodamine B, rose bengal, pigment red, etc. as magenta (M) colorants; phthalocyanine as cyan (C) colorants Blue, aniline blue, pigment blue, etc .; examples of black (K) colorants include carbon black, aniline black, blends of color pigments, and the like.

In general color toners, particles having a volume average particle diameter of 1 to 15 μm (generally referred to as “toner particles” or “colored particles”) obtained by dispersing the colorant in the thermoplastic resin. External additive fine particles having an average particle size of about 5 to 100 nm, for example, inorganic fine particles such as silicon oxide, titanium oxide and aluminum oxide, and / or resins such as polymethyl methacrylate (PMMA) and polyvinyl difluoride (PVDF) Fine particles are attached.

  The method for producing the toner particles constituting the color toner is not particularly limited, and may be a kneading and pulverizing method in addition to the above various wet production methods mentioned in the explanation of the transparent toner of the present invention. Of course, since the color toner generally has a relatively low viscosity, it is preferable to use a wet manufacturing method as with the transparent toner of the present invention.

The recording medium on which the transparent toner of the present invention and the color toner are transferred and fixed or formed is not particularly limited, and may be a general copy paper, plain paper, straw paper, or other resin sheet such as OHP paper. Absent. In addition, all sheet-like media on which image formation can be performed by the electrophotographic method are targets of the recording medium according to the present invention.
In addition, among the elements defining the transparent toner of the present invention, the contents relating to the specific steps of transferring and fixing or forming the transparent toner of the present invention and the color toner are described in detail in the section of [Glossiness imparting device] described later. I will do it.

[Transparent developer for electrophotography]
The transparent toner of the present invention described above can be used as it is as a one-component developer or as a toner in a two-component developer composed of a carrier and a toner. Hereinafter, the transparent developer for electrophotography of the present invention which is the latter two-component developer (hereinafter sometimes simply referred to as “transparent developer of the present invention”) will be described.

  The carrier that can be used in the transparent developer of the present invention is not particularly limited, and a conventionally known carrier can be used regardless of whether it is a colored toner or a colorless toner. For example, a resin-coated carrier having a resin coating layer on the surface of the core material can be exemplified. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.

Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable.
The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (mass ratio) of the transparent toner of the present invention and the carrier in the transparent developer of the present invention is preferably in the range of transparent toner: carrier = 1: 100 to 30: 100, and 3: 100 to 20: A range of about 100 is more preferable.

[Glossing device]
Next, the gloss imparting apparatus of the present invention will be described in detail.
The gloss imparting apparatus of the present invention uses a color toner containing at least a thermoplastic resin and a colorant to form a color toner image on the surface of a recording medium by an electrophotographic method, and then transparent on or around the color toner image. A gloss imparting device that imparts gloss to an image by transferring and fixing toner,
A transparent toner image carrier for carrying a transparent toner image comprising the transparent toner;
A transparent toner image forming means for forming the transparent toner image on the surface of the transparent toner image carrier;
The transparent toner image formed on the surface of the transparent toner image carrier is transferred onto the surface of the recording medium on which the color toner image is formed, and is heated and pressed to be heated and heated for fixing. Pressure means;
Cooling and peeling for cooling the transparent toner image and color toner image transferred and fixed on the surface of the recording medium and then peeling the recording medium on which the transparent toner image and color toner image are formed from the transparent toner image carrier. Means,
And comprising
The transparent toner of the present invention is used as the transparent toner.

<Before introduction to gloss applicator>
As a means for forming a color toner image on the surface of the recording medium, a conventionally known electrophotographic toner image forming apparatus can be used. A toner image forming apparatus known per se can be used as long as the purpose of forming a color image on the surface of the recording medium is satisfied.

For example, a photoconductor, a charging device facing the photoconductor, an image signal forming device for controlling an image signal for forming a color image, and the photoconductor by an image signal from the image signal forming device. An exposure device that forms a latent image by imagewise exposure, a developing device that develops the latent image on the surface of the photoreceptor with a developer layer containing color toner, and a toner formed on the surface of the photoreceptor The image forming apparatus preferably includes a transfer device that transfers an image to a recording medium.
Further, it is also preferable that an intermediate transfer member is provided, and after the toner image on the photosensitive member is once transferred to the intermediate transfer member, the toner image is transferred from the intermediate transfer member to the surface of the recording medium by a secondary transfer device.

  The photoreceptor is not particularly limited, and a conventionally known one can be adopted without any problem. The photoreceptor may have a single layer structure, or may have a multilayer structure and a function separation type. The material may be an inorganic photoreceptor such as selenium or amorphous silicon, or an organic photoreceptor (so-called OPC).

  Examples of the charging device include contact charging devices using conductive or semiconductive rollers, brushes, films, rubber blades, non-contact charging devices such as corotron charging and scorotron charging using corona discharge, and the like. Any means known per se can be used.

  As the exposure apparatus, a conventionally known exposure means such as a combination of a semiconductor laser and a scanning apparatus, a laser ROS comprising an optical system, or an LED head can be used. In order to realize a preferable mode of producing a uniform and high-resolution exposure image, it is preferable to use a laser ROS or an LED head.

  As the image signal forming apparatus, any conventionally known means can be used as long as a signal capable of forming a toner image at a desired position on the surface of the recording medium can be formed.

  As the developing device, as long as it has a function of forming a uniform and high-resolution toner image on the latent image on the surface of the photoreceptor, a conventionally known developing device is used regardless of whether it is a one-component system or a two-component system. Can do. From the viewpoint of good graininess and smooth tone reproduction, a two-component developing device is preferable.

  As the transfer device, for example, a conductive or semiconductive roller, brush, film, rubber blade, or the like to which a voltage is applied is used to create an electric field between the photosensitive member and the recording medium or the intermediate transfer member, thereby charging the transfer device. The toner image consisting of the toner particles is transferred, and the back surface of the recording medium or intermediate transfer body is corona charged with a corotron charger or scorotron charger using corona discharge to transfer the toner image consisting of the charged toner particles. Conventionally known means such as a means for performing can be used.

  As the intermediate transfer member, an insulating or semiconductive belt material or a drum-shaped one having an insulating or semiconductive surface can be used. A semiconductive belt material is preferable from the viewpoint of stably maintaining transferability during continuous image formation and reducing the size of the apparatus. As such a belt material, a belt material made of a resin material in which a conductive filler such as carbon fiber is dispersed is known. As this resin, for example, a polyimide resin is preferable.

As the secondary transfer device, for example, an electric field is generated between the intermediate transfer member and the recording medium using a conductive or semiconductive roller, brush, film, rubber blade, or the like to which a voltage is applied, and charged. Means for transferring a toner image composed of toner particles, means for corona charging the back surface of the intermediate transfer body with a corotron charger or a scorotron charger utilizing corona discharge, and a means for transferring a toner image composed of charged toner particles, etc. Known means can be used.
The toner image forming apparatus as described above can form a color toner image on the surface of the recording medium.

  The recording medium on which the color toner image is formed on the surface by the toner image forming apparatus is normally continuously conveyed to the gloss applying apparatus. As a transport device for transporting to the gloss applying device, a transport device known per se can be used. Since the gloss imparting device according to the present invention also serves as a fixing device, the color toner image may be conveyed to the gloss imparting device without fixing, or may be melted and fixed by a known fixing device before transportation. Also good. Since the conveying speed of the conveying device is preferably constant, for example, a device that drives the recording medium between a pair of rubber rolls that rotate at a constant rotational speed, or one that is driven at a constant speed by a motor or the like. It is possible to use a device that winds a belt made of rubber or the like around the pair of rolls and places the recording medium substantially horizontally on the belt to drive at a constant speed. When an unfixed color toner image is formed, the latter conveying device is preferably employed from the viewpoint of preventing the color toner image from being disturbed.

<Specific configuration>
Hereinafter, the configuration of the gloss imparting apparatus of the present invention will be specifically described with reference to embodiments.
FIG. 1 is a schematic configuration diagram of an entire image forming apparatus including a gloss imparting apparatus as an exemplary embodiment of the present invention, which is used in combination with the above-described color image forming apparatus. The image forming apparatus shown in FIG. 1 is largely divided into a toner image forming apparatus (reference numerals 2 to 16) for forming a color toner image, and a gloss applying apparatus (reference numerals 20 to 20) for transferring and fixing the transparent toner of the present invention. 33), and both are connected by the transport device 19.

  In the toner image forming apparatus, first, the document 1 to be read is irradiated with light by the illumination 2, and the reflected light is read by the color scanner 3. The read signal is sent to an image processing device (image signal forming device) 4 where it is separated into each color of yellow Y, magenta M, cyan C and black K, and an image signal for controlling exposure is output by the exposure device. It is sent to a certain optical system (ROS) 6.

  In the optical system (ROS) 6, the laser diode 5 emits light for each color component, and the surface of the organic photoconductor (photoconductor) 7 is irradiated with image-like light X for each color component. On the other hand, the organic photoreceptor 8 is rotated in the direction of arrow A, and the surface is first uniformly charged by a charger (charging device) 7 and then exposed by the optical system (ROS) 6 described above. Then, it is used for development by the developing devices 9-11.

  For example, taking the yellow Y color as an example, the surface of the organic photoreceptor 8 is irradiated by the optical system (ROS) 6 with the light separated into yellow Y color components by the image processing device 4. The surface of the organic photoreceptor 8 is uniformly charged by the charger 7 in advance, and the portion irradiated with the light is charged to the opposite polarity to form a latent image. Then, the latent image on the surface of the organic photoreceptor 8 is developed by the yellow developing device 9 with yellow Y color toner. Further, the organic photoreceptor 8 rotates in the direction of arrow A, and is transferred onto the surface of the intermediate transfer belt (intermediate transfer body) 13 by electrostatic attraction of the transfer corotron 14. The surface of the organic photoreceptor 8 after the transfer is uniformly charged by the charger 7 by further rotation in the direction of arrow A, and prepares for image formation of the next color.

Subsequent to the yellow Y color, the same operation is performed for each of the magenta M, cyan C, and black K colors, and the latent image is sequentially developed by the magenta developing unit 10, the cyan developing unit 11, and the black developing unit 12, and the intermediate transfer belt. 13 is laminated. The intermediate transfer belt 13 rotates in the direction of arrow B as the organic photoconductor 8 rotates at the time of transferring each color. When the transfer is completed, the intermediate transfer belt 13 rotates in the opposite direction and returns to the original position, and the next color is transferred. When the image is printed, it is laminated on the color toner image transferred before that. When all four colors are stacked, they are rotated in the direction of arrow B as they are and sent to the nip portion sandwiched between transfer rolls (secondary transfer devices) 15 and 16. A sheet 17 that is a recording medium on which an image is to be formed is inserted in the nip portion in the direction of arrow C in a state of being in contact with the intermediate transfer belt 13 on the surface. The laminated color toner images are transferred onto the surface of the paper 17 by the electrostatic action of the transfer rolls 15 and 16.
The sheet 17 on which the color toner image has been transferred is conveyed by the conveying device 19 to the gloss applying device.

  The gloss imparting device of this example forms an endless belt-like transparent toner image carrier 20 stretched around a plurality of rolls 30, 32, and 33 and forms a desired transparent toner image on the surface of the transparent toner image carrier 20. The transparent toner image forming means 21, the transparent toner image carrier 20 on which the transparent toner image is formed, and the recording medium 17 on which the color toner image is formed are sandwiched and heated for heating and pressurization. A pressure peeling means 22 and a cooling peeling heat sink (cooling means) for cooling the recording medium 17 transferred and fixed in a state where the transparent toner image is coated on or around the color toner image by the heating pressure means 22. 23.

  As the transparent toner image carrier 20, one comprising a fixing belt formed in an endless belt shape by a polymer film such as polyimide is used. Further, the transparent toner image carrier 20 has a resistance value obtained by dispersing conductive additives such as conductive carbon particles and a conductive polymer in order to stably form a certain amount of transparent toner image. Is preferably adjusted to a predetermined value. The shape of the transparent toner image carrier 20 is not limited to an endless shape. For example, the transparent toner image carrier 20 may have various shapes such as a web shape, a web shape, a sheet shape, etc. However, it is preferable to use an endless belt-like one as in this example.

  The surface of the transparent toner image carrier 20 is preferably coated with a silicone resin and / or a fluorine resin from the viewpoint of releasability. Further, from the viewpoint of smoothness, the transparent toner image carrier 20 preferably has a surface glossiness of 60 or more as measured by a 75 ° gloss meter.

  The transparent toner image forming means 21 forms a transparent toner image of the above-described transparent toner of the present invention on the surface of the transparent toner image carrier 20. As long as this purpose is satisfied, a developing device known per se can be diverted and used. Examples of the transparent toner image forming means include a one-component developing device, a position where a counter electrode member such as a roll or the like to which a bias voltage is applied is in contact with the back surface of the transparent toner image carrier 20. The two-component developing device may be opposed to the counter electrode member, and the transparent toner image may be directly developed on the surface of the transparent toner image carrier by the one-component developing device or the two-component developing device. In this case, the temperature of the transparent toner image carrier at the position of the device for directly developing the transparent toner is preferably 60 ° C. or less.

  In this example, the transparent toner image forming means 21 includes, as shown in FIG. 1, a photosensitive drum 24, a charging device 25 for uniformly charging the surface of the photosensitive drum 24, and the surface of the photosensitive drum 24. An exposure device 26 composed of a ROS, an LED array, or the like that forms a latent image by exposure, and a transparent toner image signal forming device 27 for controlling the area and the amount of the transparent toner image on the surface of the recording medium 17. And a transparent toner image developing device 28 for developing a latent image on the surface of the photosensitive drum 24 with a developer layer containing a transparent toner and facing the photosensitive drum 24 to obtain a transparent toner image, and a transparent surface of the photosensitive drum 24. And a transfer device 29 for transferring the toner image onto the surface of the transparent toner image carrier 20.

  The photosensitive drum 24 is not particularly limited, and a conventionally known one can be adopted without any problem. The photosensitive drum 24 may be a single layer structure, or may be a multilayer structure and a function separation type. The material of the photoconductor drum 24 may be an inorganic photoconductor such as selenium or amorphous silicon, or an organic photoconductor (so-called OPC).

  As the charging device 25, for example, a contact charging device using a conductive or semiconductive roller, brush, film, rubber blade, or the like, a non-contact charging device such as corotron charging or scorotron charging using corona discharge, etc. Any means known per se can be used.

  As the exposure device 26, a known exposure means such as a combination of a semiconductor laser and a scanning device, an optical system laser ROS, an LED head, or a halogen lamp can be used. In order to realize a preferable mode in which the exposure image area, that is, the position of the surface of the recording medium on which the transparent toner image is formed is changed as desired, it is preferable to use a laser ROS or an LED head.

  As the transparent toner image signal forming device 27, any conventionally known means can be used as long as a signal capable of forming a transparent toner image at a desired position on the surface of the recording medium 17 can be formed. The transparent toner image signal forming device 27 may form a transparent toner image forming signal based on the image data output from the image processing device 4 in the toner image forming device described above. .

  As the transparent toner image developing device 28, a conventionally known developing device can be used regardless of one-component system or two-component system as long as it has a function of forming a uniform transparent toner image on the surface of the photosensitive drum 24. .

  As the transfer device 29, for example, an electric field is created between the photosensitive drum 24 and the transparent toner image carrier 20 using a conductive or semiconductive roller, brush, film, rubber blade or the like to which a voltage is applied. The back surface of the transparent toner image carrier 20 is corona-charged by means of transferring charged transparent toner particles, a corotron charger using a corona discharge, a scorotron charger, or the like to transfer the charged transparent toner particles. Conventionally known means such as means can be used.

  In this example, the area where the transparent toner image is formed is the entire image area covering the entire color toner image on the surface of the recording medium 17. However, the present invention is not limited to this. For example, the entire surface of the recording medium 17 may be used, and a color toner image, for example, a photographic image or the like, where only a particularly high gloss area is selected. It doesn't matter. Further, in order to suppress unevenness due to the toner particles of the color toner image, the toner height of the transparent toner image is changed so as to equalize the height according to the toner height of the color toner image, or the color toner image For example, a transparent toner image may be formed only in a region where the toner image is not formed, or a transparent toner image may be formed little or not on a color toner image. Furthermore, a mode in which a transparent toner image is formed before forming a color toner image may be used. The expression “on or around the color toner image” defined in the present invention includes all these aspects.

  As the heating and pressurizing means 22 for sandwiching and sandwiching the transparent toner image carrier 20 on which the transparent toner image is formed and the recording medium 17 on which the color toner image is formed in contact with each other, A conventionally well-known thing can be used. In this example, as shown in FIG. 1, the heating and pressing unit 22 includes a pair of rolls (a heating roll 30 and a pressing roll 31) driven at a constant speed in the directions of arrows C and C ′. The transparent toner image carrier 20 on which the transparent toner image is formed and the recording medium 17 on which the color image is formed are conveyed while being sandwiched and heated and pressed. Here, one or both of the pair of rolls 30 and 31 has their surfaces heated to a temperature at which the transparent toner melts, for example, by a method including a heat source (not shown) at the center. The rolls 30 and 31 are pressed against each other via the transparent toner image carrier 20. One or both of the pair of rolls 30 and 31 is preferably provided with a silicone rubber or fluororubber layer on the surface thereof, and the length of the nip region to be heated and pressurized is in the range of about 1 to 8 mm. Is desirable.

  As shown in FIG. 1, the endless belt-like transparent toner image carrier 20 is rotatably supported by a plurality of rolls 30, 32, 33 including a heating roll 30, and the transparent toner image is supported on the heating roll 30. A pressure roll 31 is in pressure contact with the carrier 30.

  In this example, the heating roll 30 and the pressure roll 31 are formed to have a predetermined outer diameter (40 mmφ) by covering the surface of a metal core made of aluminum with an elastic body layer (thickness 2 mm) made of silicone rubber. Used. A halogen lamp (not shown) of 300 to 350 W is provided as a heating source inside the heating roll 30 and the pressure roll 31 and is heated from the inside so that the surface temperature of the heating roll 30 becomes a predetermined temperature. Is done.

  The heating roll 30 and the pressure roll 31 are in pressure contact with each other via the transparent toner image carrier 20, and in this example, a predetermined load is applied by pressure means (not shown), and the pressure contact portion (nip portion). Is configured to have a width of 8 mm. Further, the transparent toner image carrier 20 is stretched around the heating roll 30, the peeling roll 32, and the driven roll 33, and is moved at a predetermined moving speed by the heating roll 30 that is driven to rotate in the direction of arrow C by a driving source (not shown). (In this example, it is rotated in the direction of arrow D at 60 mm / sec). In this example, the transparent toner image carrier 20 is formed by coating an outer peripheral surface side of an endless film made of thermosetting polyimide having a thickness of 80 m and a silicone rubber layer having a thickness of 30 μm.

  Further, on the inner surface side of the transparent toner image carrier 20, cooling peeling as a cooling peeling device for forcibly cooling and peeling the transparent toner image carrier 20 between a heating roll 30 and a peeling roll 32. A heat sink 23 is provided, and the cooling and heat sink 23 cools and peels off the toner and the recording medium 17. A heat pipe may be used instead of the heat sink. Further, in this example, as shown in FIG. 1, a roll having a small curvature is employed as the roll (peeling roll 32) located at the peeling position, and the roll is peeled off by the waist of the recording medium itself. It is. Note that it is also a preferable aspect to dispose a peeling claw at a site where the transparent toner image carrier 20 and the recording medium 17 are to be peeled off.

A process in which the recording medium 17 on which the color toner image is formed is transported by the transport device 19 and introduced into the gloss applying device having the above-described configuration, and image gloss is imparted will be described.
The recording medium 17 on which the color toner image is formed (transferred) on the surface has a color contact portion (nip portion) between the heating roller 30 and a pressure roller 31 that is pressed against the heating roller 30 via the transparent toner image carrier 20. The toner image is introduced so as to face the heating roll 30 side.

  FIG. 2 is a schematic enlarged cross-sectional view schematically showing the state between the transparent toner image carrier 20 and the recording medium 17 while passing through the pressure contact portion between the heating roll 30 and the pressure roll 31. In FIG. 2, 34 is a transparent toner image carried by the transparent toner image carrier 20, 35 is a color toner image formed on the recording medium 17, and a pair of rolls 30 and 31 are omitted. As shown in FIG. 2, the color toner image 35 is heated and melted on the surface of the recording medium 17, and at the same time, the transparent toner image 34 formed on the surface of the transparent toner image carrier 20 is over the color toner image 35. The surroundings are heated and melted and fused to cover the whole.

Thereafter, the color toner image 35 and the transparent toner image 34 are heated to a temperature of about 120 to 130 ° C. and melted at the press contact portion between the heating roll 30 and the pressure roll 31. The recording medium 17 to which the transparent toner image 34 and the color toner image 35 are fused has the transparent toner image 34 on the surface thereof in close contact with the surface of the transparent toner image carrier 20. 20 is conveyed along with arrow D in the direction of arrow D. In the meantime, the transparent toner image carrier 20 is forcibly cooled by the cooling heat sink 23 and the transparent toner image 34 and the color toner image 35 are cooled and solidified. Rigidity).
The surface of the transparent toner image carrier 20 after the peeling process is completed is prepared for the next fixing process by removing residual toner and the like by a cleaner (not shown) as necessary.

  As mentioned above, although the glossiness imparting device of the present invention has been described with a preferable example, the present invention is not limited to the above example, as long as the configuration of the present invention is provided, or from the conventionally known knowledge, or The configuration of the present invention can be replaced by a technique newly discovered or invented for the present invention.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

The physical properties of the toner materials in the following examples were evaluated as follows.
-Molecular weight measurement: Gel permeation chromatography is used. Tetrahydrofuran is used as the solvent.
The average particle diameter of the toner was measured using a Coulter counter, and a volume average d ₅₀ was applied.
In addition, the viscosity of the resin was measured under an angular velocity of 1 rad / s using a rotary plate rheometer (Rheometers RDAII).

[Synthesis of polyester resin]
(Synthesis of polyester resin A)
194 parts by weight of dimethyl terephthalate, 152 parts by weight of 1,9-nonanediol, 3.10 parts by weight of ethylene glycol, 16.92 parts by weight of bisphenol S ethylene oxide adduct, and 0.15 parts by weight of dibutyltin oxide as a catalyst Were put into a heat-dried three-necked flask, and the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, followed by mechanical stirring at 180 ° C. for 5 hours.

Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the distillate disappeared and became viscous, the mixture was air-cooled to stop the reaction. The obtained resin was designated as polyester resin A.
The obtained polyester resin A had a mass average molecular weight (Mw) of 33,000 and a number average molecular weight (Mn) of 14,000 as determined by gel permeation chromatography.
Further, when the melting point (Tm) of the polyester resin A was measured using a differential scanning calorimeter (DSC) by the above-described measurement method, it had an endothermic peak derived from crystals, and the peak top temperature was 85 ° C. It was.

(Synthesis of polyester resin B)
194 parts by weight of dimethyl terephthalate, 157 parts by weight of 1,9-nonanediol, 1.24 parts by weight of ethylene glycol, 6.77 parts by weight of bisphenol S ethylene oxide adduct, and 0.15 parts by weight of dibutyltin oxide as a catalyst Were put into a heat-dried three-necked flask, and the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, followed by mechanical stirring at 180 ° C. for 5 hours.

Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the distillate disappeared and became viscous, the mixture was air-cooled to stop the reaction. The obtained resin was designated as polyester resin B.
According to molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained polyester resin B had a mass average molecular weight (Mw) of 24,500 and a number average molecular weight (Mn) of 11,700.
Further, when the melting point (Tm) of the polyester resin B was measured by a differential scanning calorimeter (DSC) by the above-described measurement method, it had an endothermic peak derived from crystals, and the peak top temperature was 88 ° C. It was.

(Synthesis of polyester resin C)
194 parts by mass of dimethyl terephthalate, 152 parts by mass of 1,9-nonanediol, 16.92 parts by mass of bisphenol S ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst The flask was put into a flask, and the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, followed by stirring at 200 ° C. for 5 hours by mechanical stirring.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as polyester resin C.
By the molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained polyester resin C had a mass average molecular weight (Mw) of 13,200 and a number average molecular weight (Mn) of 6,000.
Further, when the melting point (Tm) of the polyester resin C was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had an endothermic peak derived from crystals, and the peak top temperature was 80 ° C. It was.

(Synthesis of polyester resin D)
194 parts by weight of dimethyl terephthalate, 144 parts by weight of 1,9-nonanediol, 6.21 parts by weight of ethylene glycol, 33.84 parts by weight of bisphenol S ethylene oxide adduct, and 0.15 parts by weight of dibutyltin oxide as a catalyst Were put into a heat-dried three-necked flask, and the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, followed by mechanical stirring at 180 ° C. for 5 hours.

Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the distillate disappeared and became viscous, the mixture was air-cooled to stop the reaction. The obtained resin was designated as polyester resin D.
In the molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained polyester resin D had a mass average molecular weight (Mw) of 24,000 and a number average molecular weight (Mn) of 11,000.

  Further, when the melting point (Tm) of the polyester resin D was measured by a differential scanning calorimeter (DSC) according to the above-described measurement method, no endothermic peak derived from crystals was observed, and a stepwise endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 55 ° C.

(Synthesis of polyester resin E)
194 parts by mass of dimethyl terephthalate, 152 parts by mass of 1,9-nonanediol, 15.81 parts by mass of bisphenol A ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst The flask was put into a flask, and the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, followed by mechanical stirring at 180 ° C. for 5 hours.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as polyester resin E.
By the molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained polyester resin E had a mass average molecular weight (Mw) of 22,400 and a number average molecular weight (Mn) of 10,900.
Further, when the melting point (Tm) of the polyester resin E was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had an endothermic peak derived from crystals and the peak top temperature was 90 ° C. It was.

(Synthesis of polyester resin F)
194 parts by mass of dimethyl terephthalate, 120 parts by mass of 1,9-nonanediol, 79.1 parts by mass of bisphenol A ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst The flask was put into a flask, and the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, followed by mechanical stirring at 180 ° C. for 5 hours.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as polyester resin F.
The obtained polyester resin F had a mass average molecular weight (Mw) of 17,100 and a number average molecular weight (Mn) of 7,675 as determined by gel permeation chromatography.

  Further, when the melting point (Tm) of the polyester resin F was measured by a differential scanning calorimeter (DSC) according to the above-described measurement method, no endothermic peak derived from crystals was observed, and a stepwise endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 42 ° C.

(Synthesis of polyester resin G)
194 parts by mass of dimethyl terephthalate, 160 parts by mass of 1,9-nonanediol, and 0.15 parts by mass of dibutyltin oxide as a catalyst are placed in a heat-dried three-necked flask, and the air in the container is reduced to nitrogen by a depressurization operation. Under an inert atmosphere with gas, stirring was performed at 180 ° C. for 5 hours by mechanical stirring.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as polyester resin G.
According to molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained polyester resin G had a mass average molecular weight (Mw) of 24,000 and a number average molecular weight (Mn) of 10,900.
Further, when the melting point (Tm) of the polyester resin G was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had an endothermic peak derived from crystals, and the peak top temperature was 94 ° C. It was.

(Synthesis of polyester resin H)
Put 202 parts by weight of sebacic acid, 62.07 parts by weight of ethylene glycol, 16.92 parts by weight of bisphenol S ethylene oxide adduct, and 0.15 parts by weight of dibutyltin oxide as a catalyst in a heat-dried three-necked flask. The air in the container was put under an inert atmosphere with nitrogen gas by depressurization, and the mixture was stirred at 180 ° C. for 5 hours by mechanical stirring.

Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the distillate disappeared and became viscous, the mixture was air-cooled to stop the reaction. The obtained resin was designated as polyester resin H.
According to molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained polyester resin H had a mass average molecular weight (Mw) of 12,000 and a number average molecular weight (Mn) of 5,600.
Further, when the melting point (Tm) of the polyester resin H was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had an endothermic peak derived from crystals, and the peak top temperature was 60 ° C. It was.

[Visibility reflectance Y]
The luminous reflectance Y of the obtained polyester resin was measured according to the following procedure.
Each polyester resin to be measured was applied on a color OHP sheet manufactured by Fuji Xerox Co., Ltd. so as to have a dry film thickness of 20 μm to form a transparent image.
A cover glass for microscopic observation was placed on the front and back surfaces of the transparent image, and the gap between the image and the cover glass was filled with tetradecane to obtain a test material.
The obtained specimen was color measured with X-rite 968 on a light trap to measure Y ′.

A cover glass for microscopic observation was overlapped on the front and back surfaces of the OHP sheet to which the polyester resin was not applied. Similarly, the gap between the OHP sheet and the cover glass was filled with tetradecane, and Y ₀ was measured in the same procedure. The luminous reflectance Y was calculated by the following calculation formula.
Y = Y′−Y ₀

  The composition and molar ratio of each polyester resin obtained, luminous reflectance Y, and various physical properties (molecular weight, melting point (Tm), etc. are summarized in Table 1 below.

[Example 1]
-Transparent toner and developer-
The polyester resin A was placed in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersed using an Ultra Turrax T50 (manufactured by IKA-Labortenik) at a rotational speed of 4000 rpm for 1 hour.
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles with d ₅₀ = 12 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles A1 and B1 were attached to 100 parts by mass of the fine particles with a high-speed mixer to obtain a transparent toner J1 of Example 1. The obtained transparent toner J1 had a Tm of 85 ° C.
Inorganic fine particles A1: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particles B1: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

  Furthermore, 8 parts by mass of the obtained transparent toner J1 and 100 parts by mass of the same carrier as the black developer for Acolor 635 (Fuji Xerox Co., Ltd.) are mixed, and the two-component transparent developer of Example 1 is mixed. J1 was produced.

-Color toner and developer-
As a binder resin, a linear polyester resin obtained from terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol (molar ratio = 5: 4: 1, Tg = 62 degrees, Mn = 4,500, Mw = 10, 000) with respect to 100 parts by weight of the colorant (for yellow toner: 5 parts by weight of benzidine yellow, for magenta toner: 4 parts by weight of pigment red, for cyan toner: phthalocyanine blue 4) Parts by mass, and in the case of black toner: 5 parts by mass of carbon black), heated and melted and mixed using a Banbury mixer, pulverized with a jet mill, and then classified with a wind classifier. ₅₀ = 7 μm fine particles (toner particles) were prepared.

The following two types of inorganic fine particles A1 ′ and B1 ′ were adhered to 100 parts by mass of the fine particles with a high-speed mixer to obtain four color toners Y, M, C and K. The obtained color toners Y, M, C and K had Tm ′ of 105 ° C.
Inorganic fine particles A1 ′: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particle B1 ′: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

  Further, each of the obtained color toners Y, M, C, and K, 8 parts by mass, and 100 parts by mass of the same carrier as the black developer for Acolor 635 (manufactured by Fuji Xerox Co., Ltd.) are mixed, respectively. Developers Y, M, C and K were prepared. However, as will be described later, this mixing ratio is finely adjusted later depending on various conditions during development.

-Color image formation (including gloss)-
The two-component transparent developer J1 of the present embodiment obtained above by the image forming apparatus (including a toner image forming apparatus and a gloss imparting apparatus) as a preferred example described with reference to FIGS. A color image (portrait photographic image) was formed using the two-component color developers Y, M, C and K.

Various image forming conditions are shown below with reference to FIGS. Note that image forming conditions other than the following conditions are as described above.
The speed of the image forming process excluding the transfer fixing process in the gloss applying device: 160 mm / s
Color toner image formation conditions: The mass ratio of each color toner to the carrier, the photosensitive member charging potential, so that the development amount of the color toner in the solid image portion is 0.7 (mg / cm ² ) for each color, Adjust exposure and development bias

Recording medium 17: A recording medium in which a light scattering layer is formed on the surface of a base paper and a back layer is formed on the back surface. Details are as follows.
(Base paper)
The base paper was made of pulp raw material and had a thickness of 150 μm.
(Light scattering layer)
Titanium dioxide (KA-10 manufactured by Titanium Industry Co., Ltd., particle size 300 to 500 nm) was mixed at a ratio of 25 parts by mass with respect to 100 parts by mass of the polyethylene resin, and charged into a melt extruder heated to 200 ° C. A light scattering layer (light diffusion layer) having a thickness of 30 μm was formed by niping and laminating between the nip roll and the cooling roll on the surface of the base paper discharged from the T-die and flame-treated. Here, both surfaces of the film after passing through the T die are subjected to corona discharge treatment by a corona treatment device. In this light scattering layer, the temperature Tb at which the viscosity becomes 5 × 10 ³ Pa · S is 130 ° C.

(Back layer)
Thickness of 30 μm by putting polyethylene resin into a melt extruder heated to 200 ° C., discharging from a T-die, and niping and laminating between the nip roll and cooling roll on the flame treated base paper backside A polyethylene layer was prepared, and colloidal silica was further applied thereon as an antistatic agent with a bar coater to form an antistatic layer. Here, both surfaces of the film after passing through the T die are subjected to corona discharge treatment by a corona treatment device.

Transparent toner image carrier 20: Polyimide film in which conductive carbon black having a thickness of 80 μm is dispersed is used as a belt base material, and KE4895 silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the surface to obtain a thickness. The one coated with a 50 μm silicone rubber layer was used.

Heating roll 30 and pressure roll 31: A silicone rubber layer having a thickness of 2 mm is provided on the peripheral surface of an aluminum core, and a halogen lamp is disposed as a heat source at the center thereof. The temperature of the peripheral surface was changed between 100 ° C and 170 ° C.

-Process speed of the transfer fixing process in the gloss applying device: 30 mm / second. When the peripheral surface temperature of the heating roll 30 and the pressure roll 31 is a predetermined temperature, the temperature of the recording medium 17 at the peeling position in the gloss applying device is cooled to 70 ° C. by the heat sink 3.
-Toner amount in transparent toner image: 20.0 g / m ²
Area where the transparent toner image is formed: The entire area covering the entire area where the color toner image is formed.

[Example 2]
Example 1 is the same as Example 1 except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner J2 and the two-component transparent developer J2 of Example 2 produced as follows were used. A color image was formed in the same manner as described above.

-Transparent toner and developer-
Polyester resin B was put in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersion was performed for 1 hour at a rotational speed of 4000 rpm using UltraTurrax T50 (manufactured by IKA-Labortenik).
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles A2 and B2 were attached to 100 parts by mass of the fine particles with a high-speed mixer to obtain a transparent toner J2 of Example 2. The obtained transparent toner J2 had a Tm of 88 ° C.
Inorganic fine particles A2: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particles B2: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, added amount 1.0 part by mass)

  Furthermore, 8 parts by mass of the obtained transparent toner J2 and 100 parts by mass of the same carrier as the black developer for Acolor 635 (Fuji Xerox Co., Ltd.) are mixed, and the two-component transparent developer of Example 2 is mixed. J2 was produced.

[Example 3]
Example 1 is the same as Example 1 except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner J3 and the two-component transparent developer J3 of Example 3 prepared as follows were used. A color image was formed in the same manner as described above.

-Transparent toner and developer-
The polyester resin C was placed in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersed using an Ultra Turrax T50 (manufactured by IKA-Labortenik) at a rotational speed of 4000 rpm for 1 hour.
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles A3 and B3 were adhered to 100 parts by mass of the fine particles with a high speed mixer to obtain a transparent toner J3 of Example 3. The obtained transparent toner J3 had a Tm of 80 ° C.
Inorganic fine particle A3: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particle B3: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

  Furthermore, 8 parts by mass of the obtained transparent toner J3 and 100 parts by mass of the same carrier as the black developer for Acolor 635 (Fuji Xerox Co., Ltd.) are mixed, and the two-component transparent developer of Example 3 is mixed. J3 was produced.

Example 4
In Example 1, instead of the color toners Y, M, C, and K, the color toner for each color for DCC500 (Fuji Xerox Co., Ltd.) was used, and the carrier was mixed in the same manner as in Example 1. Two-component color developers Y ′, M ′, C ′ and K ′ were prepared, and a color image was formed in the same manner as in Example 1.
The Tm ′ of the color toner used in this example was 100 ° C.

[Example 5]
In Example 4, Example 4 was used except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner J5 and the two-component transparent developer J5 of Example 5 produced as follows were used. A color image was formed in the same manner as (including the conditions of Example 1 diverted in Example 4).

-Transparent toner and developer-
The polyester resin C was placed in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersed using an Ultra Turrax T50 (manufactured by IKA-Labortenik) at a rotational speed of 4000 rpm for 1 hour.
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, washed thoroughly with water, and then subjected to reduced pressure and lyophilization.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles A5 and B5 were adhered to 100 parts by mass of the fine particles with a high speed mixer to obtain a transparent toner J5 of Example 5. The obtained transparent toner J5 had a Tm of 80 ° C.
Inorganic fine particle A5: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, added amount 1.0 part by mass)
Inorganic fine particle B5: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

  Furthermore, 8 parts by mass of the obtained transparent toner J5 and 100 parts by mass of the same carrier as the black developer for Acolor 635 (Fuji Xerox Co., Ltd.) are mixed, and the two-component transparent developer of Example 5 is mixed. J5 was produced.

[Comparative Example 1]
Example 1 is the same as Example 1 except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner h1 and the two-component transparent developer h1 of Comparative Example 1 produced as follows were used. A color image was formed in the same manner as described above.

-Transparent toner and developer-
The polyester resin D was placed in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersion was performed for 1 hour at a rotational speed of 4000 rpm using an Ultra Turrax T50 (manufactured by IKA-Labortenik).
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles C1 and D1 were attached to 100 parts by mass of the fine particles with a high-speed mixer to obtain a transparent toner h1 of Comparative Example 1 .
Inorganic fine particles C1: SiO ₂ (hydrophobic treatment of the surface with a silane coupling agent, average particle size 0.05 .mu.m, amount 1.0 part by weight)
Inorganic fine particles D1: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

[Comparative Example 2]
Example 1 is the same as Example 1 except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner h2 and the two-component transparent developer h2 of Comparative Example 2 prepared as follows were used. A color image was formed in the same manner as described above.

-Transparent toner and developer-
The polyester resin E was placed in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersion was performed for 1 hour at a rotational speed of 4000 rpm using an Ultra Turrax T50 (manufactured by IKA-Labortenik).
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles C2 and D2 were adhered to 100 parts by mass of the fine particles with a high-speed mixer to obtain a transparent toner h2 of Comparative Example 2. The obtained transparent toner h2 had a Tm of 90 ° C.
Inorganic fine particles C2: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particles D2: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

[Comparative Example 3]
Example 1 is the same as Example 1 except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner h3 and the two-component transparent developer h3 of Comparative Example 3 prepared as follows were used. A color image was formed in the same manner as described above.
-Transparent toner and developer-

The polyester resin F was placed in a 3% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersed using an Ultra Turrax T50 (manufactured by IKA-Labortehnik) at a rotational speed of 4000 rpm for 1 hour.
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles C3 and D3 were adhered to 100 parts by mass of the fine particles with a high-speed mixer to obtain a transparent toner h3 of Comparative Example 3. In the obtained transparent toner h3, no clear Tm was observed, and the glass transition temperature Tg was 42 ° C.
Inorganic fine particles C3: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particle D3: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

[Comparative Example 4]
Example 1 is the same as Example 1 except that instead of the transparent toner J1 and the two-component transparent developer J1, the transparent toner h4 and the two-component transparent developer h4 of Comparative Example 4 prepared as follows were used. A color image was formed in the same manner as described above.

-Transparent toner and developer-
The polyester resin G was placed in a 5% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersion was performed using an Ultra Turrax T50 (manufactured by IKA-Labortenik) at a rotation speed of 4000 rpm for 1 hour.
This was further returned to room temperature, diluted 5 times, adjusted to pH 9.5 with a 0.2 M sodium hydroxide aqueous solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles C4 and D4 were adhered to 100 parts by mass of the fine particles with a high-speed mixer to obtain a transparent toner h4 of Comparative Example 4. The obtained transparent toner h4 had a Tm of 94 ° C.
Inorganic fine particles C4: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particle D4: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, addition amount 1.0 part by mass)

[Comparative Example 5]
In Example 1, instead of the transparent toner J1 and the two-component transparent developer J1, Example 1 was used except that the transparent toner h5 and the two-component transparent developer h5 of Comparative Example 5 produced as follows were used. A color image was formed in the same manner as described above.

-Transparent toner and developer-
The polyester resin H was placed in a 2% carboxymethylcellulose aqueous solution heated to 98 ° C. so as to be 5% by mass, and dispersed using an Ultra Turrax T50 (manufactured by IKA-Labortenik) at a rotation speed of 4000 rpm for 1 hour.
This was further returned to room temperature, diluted 2 times, adjusted to pH 9.5 with 0.2 M aqueous sodium hydroxide solution, and stirred with a stirrer at 200 rpm for 1 hour.

After filtering the obtained dispersion, the particles on the filter paper were washed with water, and further stirred with a stirrer at 200 rpm for 1 hour in a liquid adjusted to pH 4.0 with 0.2M nitric acid. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
Fine particles having d ₅₀ = 16 μm were prepared by classifying the dried dispersed particles with an air classifier.

The following two types of inorganic fine particles C5 and D5 were adhered to 100 parts by mass of the fine particles with a high speed mixer to obtain a transparent toner h5 of Comparative Example 5. The obtained transparent toner h5 had a Tm of 60 ° C.
Inorganic fine particle C5: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, addition amount 1.0 part by mass)
Inorganic fine particles D5: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, added amount 1.0 part by mass)

[Comparative Example 6]
In Example 1, a color image was produced in the same manner as in Example 1 except that the transparent toner J1 and the two-component transparent developer J1 were not used.
In each Example and Comparative Example, the type and melting point (Tm) of the polyester resin used for the binder resin of the transparent toner, and the melting point (Tm ′) of the color toner are summarized in Table 2 below.

[Evaluation test]
The following evaluation tests were performed on the transparent toners and the two-component transparent developers of the above Examples and Comparative Examples at the time of production, color image formation, and the like.

<Dispersibility (manufacturability) evaluation>
When preparing transparent toners of Examples and Comparative Examples, when a polyester resin is put into a dispersing device (Ultra Turrax T50) and dispersed to obtain a dispersion (a state immediately before filtration with a filter paper), dispersion is not performed. The ratio (dispersion residue [mass%]) of the residue adhering to the container wall surface and bottom surface of the apparatus to the amount initially placed in the dispersion apparatus was examined. About the value of this dispersion | distribution residue, the dispersibility was evaluated on the following evaluation criteria. This evaluation of dispersibility can be an index for evaluating manufacturability. The results are summarized in Table 3 below.
○: Less than 20% by mass Δ: 20% by mass or more, less than 40% by mass ×: 40% by mass or more

<Image evaluation>
(Mechanical strength)
The recording medium 17 on which the color image finally obtained in the examples and comparative examples was formed was wound around metal rolls having different radii so that the image surface faced outward, and the minimum radius not causing cracks was examined. . From the result of the minimum radius, the mechanical strength of the image was evaluated according to the following evaluation criteria. The results are summarized in Table 3 below.
○: Less than 10 mm Δ: 10 mm or more, less than 30 mm x: 30 mm or more

(Heat-resistant)
Two recording media 17 on which color images finally obtained in the examples and comparative examples were formed were prepared, and the image surfaces were brought into contact with each other, and a load of 2.94 kPa (30 g weight / cm ² ) was applied. In this state, it was placed in a constant temperature layer maintained at 45 ° C. and left for 3 days. Then, it returned to room temperature of about 22 degreeC, and peeled both. The degree of peeling at that time was evaluated according to the following evaluation criteria, and this was regarded as the heat resistance evaluation result. The results are summarized in Table 3 below.
○: The image surface was not destroyed and peeled off without any sense of incongruity.
Δ: There is no destruction of the image surface, but there was a feeling of adhesion or peeling sound at the time of peeling.
X: The image surface was destroyed.

(Low temperature gloss)
In Example and Comparative Example, a recording medium on which a color image was formed while the peripheral surface temperature of the heating roll 30 and the pressure roll 31 was raised from 100 ° C. in units of ° C., and the finally obtained color image was formed The glossiness of the white paper portion of the image (the portion where the transparent toner image is formed but the color image is not formed) was measured with a 75 ° gloss meter (Murakami Color Research Laboratory Co., Ltd.). . The measurement was finished when the glossiness reached 90 or higher, or when the peripheral surface temperature of the heating roll 30 and the pressure roll 31 reached 170 ° C. The low temperature glossiness was evaluated according to the following evaluation criteria based on the peripheral surface temperatures of the heating roll 30 and the pressure roll 31 at the end. The results are summarized in Table 3 below.
○: Less than 110 ° C Δ: 110 ° C or more, less than 130 ° C x: 130 ° C or more

(Smoothness)
Similarly to the above (low-temperature glossiness), color images are formed while increasing the peripheral surface temperature of the heating roll 30 and the pressure roll 31, and the range between the lowest temperature and the highest temperature at which bubbles could not be recognized on the image surface ( Latitude). From the obtained results, the smoothness was evaluated according to the following evaluation criteria. The results are summarized in Table 3 below.
○: 30 ° C or more Δ: 10 ° C or more, less than 30 ° C x: 10 ° C or less

(Solidification speed)
When color images were formed in the examples and comparative examples, the state of the image (mainly the transparent toner image on the surface) formed on the surface of the recording medium 17 just output from the peeling position in the gloss applying device was observed. Evaluation was made based on the evaluation criteria, and this was used as the evaluation result of the solidification rate. The results are summarized in Table 3 below.
○: When the image is completely solidified, and fingerprints are not formed even when touched with the hand.
Δ: Although the image was not completely solidified, there was no problem in the smoothness of the image surface even when the image surface on the recording medium 17 to be output next overlapped even though the image surface could be output without defects. If.
X: The image is not solidified, the image surface is not smooth and uneven in gloss, or even after passing through the part of the peeling roll 32, the image sticks to the surface of the transparent toner image carrier 20 and cannot be peeled off. if you did this.

(Total picture quality)
In Examples and Comparative Examples, when color images are formed by setting the peripheral surface temperature of the heating roll 30 and the pressure roll 31 to 140 ° C., the overall evaluation of the finally obtained image is as follows. Sensory evaluation was performed based on the criteria. The sensory evaluation was performed by 10 people.
Very preferred: 5 points preferred: 4 points Normal: 3 points Unfavorable: 2 points Very unfavorable: 1 point

Based on the average score of 10 evaluators, the overall image quality was evaluated according to the following evaluation criteria. The results are summarized in Table 3 below.
○: 3.5 points or more Δ: 2.5 ° C or more and less than 3.5 points ×: less than 2.5 points

<Consideration of results>
In Examples 1 to 4, good results were obtained for almost all evaluation items. These have high overall image quality, and preferable images are obtained. However, in Example 2, when the transparent toner was produced, the dispersibility was slightly low, and although the level was not problematic in practical use, the yield was slightly low.
In Example 5, the smoothness was slightly low and the overall image quality was slightly inferior to that of the other examples, but it was at a level causing no practical problems.

On the other hand, in Comparative Examples 1-3, the result of the solidification temperature was bad and it was not possible to peel off at the site of the peeling roll 32. After passing through the part of the peeling roll, it was peeled off from the transparent toner image carrier 20 by hand. As a result, the image surface was not smooth and gloss unevenness occurred.
In Comparative Examples 1 and 3, in the heat resistance test, the faced image surfaces were bonded to each other and could not be peeled off. In Comparative Example 2, the overall gloss was low and the overall image quality was inferior.

In Comparative Example 4, although it was possible to peel off at the site of the peeling roll 32, the next recording medium 17 was output and the image surface was not completely solidified when overlaid on the image. Uneven gloss occurred. In addition, the overall gloss was low and the overall image quality was poor.
In Comparative Example 5, heat resistance and mechanical strength were poor.

In Comparative Example 6, the gloss at the low density part and the high density part was high, but the smoothness was poor and the gloss was low at the medium density part. Therefore, the overall image quality was extremely inferior.
From the above results, the present invention satisfies all the various physical properties required for an image, such as mechanical strength, heat resistance, low-temperature glossiness, smoothness, and has a high solidification speed, high overall image quality, and a preferable image. It has been found that the obtained transparent toner and transparent developer, and a gloss imparting device capable of forming a preferable image can be provided by using the transparent toner.

1 is a schematic configuration diagram of an entire image forming apparatus including a gloss imparting apparatus as an exemplary embodiment of the present invention used in combination with a color image forming apparatus. FIG. 2 is a schematic enlarged cross-sectional view schematically illustrating a state between a transparent toner image carrier and a recording medium while passing through a pressure contact portion between a heating roll and a pressure roll in FIG. 1.

Explanation of symbols

  1: Document, 2: Illumination, 3: Color scanner, 4: Image processing device, 5: Laser diode, 6: Optical system (ROS), 7: Charger, 8: Organic photoreceptor, 9: Yellow developer, 10 : Magenta developer, 11: Cyan developer, 12: Black developer, 13: Intermediate transfer belt, 14: Transfer corotron, 15, 16: Transfer roll, 17: Recording medium, 19: Transport device, 20: Transparent toner image Carrier: 21: Transparent toner image forming means, 22: Heating and pressing means, 23: Heat sink, 24: Photosensitive drum, 25: Charging device, 26: Exposure device, 27: Transparent toner image signal forming device, 28: Transparent Toner image developing device, 29: transfer device, 30: heating roll, 31: pressure roll, 32: peeling roll, 33: driven roll, 34: transparent Toner image, 35: color toner image

Claims (1)

A transparent toner for forming a color toner image on the surface of a recording medium by electrophotography using a color toner containing at least a thermoplastic resin and a colorant, and then transferring and fixing it on or around the color toner image. And
The aromatic component as an acid-derived constituent component is 90 mol% or more with respect to the total acid-derived constituent component, and the linear aliphatic diol as the alcohol-derived constituent component is 85 to 98 mol% with respect to the total alcohol-derived constituent component. The crystalline polyester resin included in the range includes 70% by mass or more of the total binder resin component as a binder resin,
When a film having a thickness of 20 μm is obtained from the polyester resin, the luminous reflectance Y of the film is 1.5% or less, and
The transparent toner for electrophotography, wherein the polyester resin contains bisphenol S or a bisphenol S alkylene oxide adduct in a range of 2 to 15 mol% with respect to all alcohol-derived constituent components.

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