JP2011128449A - Fixing liquid, fixing method, fixing device, image forming method, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing liquid that prevents offset while minimizing a quantity of attached fixing liquid even in high speed printing, and to provide a fixing method using the fixing liquid, a fixing device, an image forming method, and an image forming apparatus. <P>SOLUTION: The fixing liquid for fixing resin fine particles to a recording medium includes: a diluent containing water; a frother for making the fixing liquid foamy; a plasticizer for dissolving or swelling at least some of the resin fine particles, thereby softening them; and a wettability improving agent for improving the ability to wet the resin fine particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixing solution, and a fixing method, a fixing device, an image forming method, and an image forming device using the fixing solution.

  An image forming apparatus such as a printer, a facsimile machine, a copying machine, or a multi-function machine having a plurality of these functions includes characters and symbols on a recording medium such as paper, cloth, OHP sheet, etc., based on image information. Although an image is formed, an electrophotographic image forming apparatus is widely used because a high-definition image can be formed on plain paper at a high speed. In such an electrophotographic image forming apparatus, since the fixing speed is high and the quality of the fixed image is high, the toner on the recording medium is heated and melted, and the toner is pressed by pressurizing the melted toner. A heat fixing method for fixing on top is widely used.

However, in such an electrophotographic image forming apparatus using the thermal fixing method, about half or more of the power consumption is consumed for heating the toner, and there is a problem that it is difficult to save energy. Yes.
Therefore, from the viewpoint of countermeasures for environmental problems in recent years, a fixing device with low power consumption (energy saving), that is, a fixing device of a non-heating fixing method that fixes toner on a recording medium without heating is desired.

As such a non-heat fixing method, for example, a wet fixing method is disclosed in which the toner is softened by attaching an organic solvent capable of dissolving or swelling the toner. For example, a method has been proposed in which a fixing liquid is generated in a foam form, and the film thickness of the generated foam-like fixing liquid is controlled and applied to resin fine particles on a recording medium to fix the resin fine particles on the recording medium. (See Patent Document 1).
Also, a method of fixing the toner image by preventing the toner image from being disturbed and offset by making the application time for applying the foamy fixing solution longer than the permeation time until the foamy fixing solution penetrates the resin fine particle layer and reaches the recording medium. Has been proposed (see Patent Document 2).

However, in such a fixing method, the time during which the foam-like fixing solution is applied is shortened during high-speed printing, so that the application time is shorter than the time during which the foam-like fixing solution penetrates the resin fine particle layer, and offset occurs. There's a problem.
Further, when the bulk density of the foam-like fixing solution is lowered in order to reduce the adhesion amount of the fixing solution, there is a problem that the time during which the foam-like fixing solution penetrates the resin fine particle layer becomes longer than the application time and offset occurs.

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention provides a fixing solution capable of preventing an offset while keeping the amount of the fixing solution applied to a small amount even during high-speed printing, and a fixing method, a fixing device, an image forming method, and an image forming device using the fixing solution. The purpose is to do.

Means for solving the above problems are as follows. That is,
<1> A fixing solution for fixing resin fine particles to a recording medium, wherein a diluent containing water, a foaming agent that makes the fixing solution foamed, and at least a part of the resin fine particles are dissolved or swollen. A fixing liquid comprising: a plasticizer to be softened; and a wettability improving agent that increases wettability to the resin fine particles.
<2> A fixing solution for fixing resin fine particles to a recording medium, wherein a contact angle of the fixing solution with respect to an unfixed resin layer formed of the resin fine particles is determined when the fixing solution contacts the resin layer. The fixing solution has a temperature of 40 degrees or less within 0.3 seconds.
<3> The fixing solution according to <1>, wherein the wettability improving agent has a functional group having an affinity for resin fine particles.
<4> The fixing solution according to any one of <1> and <3>, wherein the wettability improving agent is a compound having an ester group in the molecule.
<5> The fixing solution according to any one of <1>, <3>, and <4>, wherein the wettability improving agent is an alcohol alkoxylate.
<6> The fixing solution according to any one of <1> to <5>, further including a viscosity modifier that adjusts the viscosity of the fixing solution.
<7> The fixing solution according to any one of <1> to <6>, which contains a solubilizer that promotes softening of the resin fine particles.
<8> The fixing liquid according to any one of <1> to <7>, wherein the resin fine particles are toner.
<9> A foam-like fixing solution generating step for producing a foam-like fixing solution by foaming the fixing solution according to any one of <1> to <8>, and the foam-like fixing solution as a foam-like fixing solution. A film thickness adjusting step for forming a desired thickness on the contact surface of the applying means, and a foam-like fixing solution applying step for applying the foam-like fixing solution formed to the desired thickness to the resin fine particle layer on the recording medium; The fixing method is characterized by including:
<10> Foamed fixer generating means for generating a foamy fixer by foaming the fixer according to any one of <1> to <8>, and the foamed fixer on a recording medium A fixing device comprising: a foamy fixing solution applying unit applied to the resin fine particle layer; and a film thickness adjusting unit configured to adjust a film thickness of the foamed fixing solution of the foamed fixing solution applying unit.
<11> An electrostatic latent image forming step for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image is developed using a developer containing a toner having resin fine particles and visible An image forming method comprising: a developing step for forming an image; a transfer step for transferring the visible image to a recording medium; and a fixing step for fixing the transferred image transferred to the recording medium. Is an image forming method, which is performed by the fixing method according to <9>.
<12> An electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image with toner having resin fine particles An image having development means for developing a visible image by using an agent, transfer means for transferring the visible image to a recording medium, and fixing means for fixing the transfer image transferred to the recording medium An image forming apparatus, wherein the fixing unit is the fixing device according to <10>.

  According to the present invention, it is possible to solve the above-described problems and achieve the object, and a fixing solution capable of preventing offset while suppressing the application amount of the fixing solution even during high-speed printing, and the fixing solution A fixing method, a fixing device, an image forming method, and an image forming apparatus using the image forming apparatus can be provided.

FIG. 1 is a schematic cross-sectional view showing how resin fine particles are fixed after applying a fixing solution according to the present invention. FIG. 2 is a schematic cross-sectional view showing the configuration of the foamy fixing solution. FIG. 3 is a schematic view showing the configuration of the foamy fixing solution generating means in the fixing device according to the present invention. FIG. 4A is a schematic configuration diagram illustrating an example of a film thickness adjusting unit and a foamy fixing solution applying unit in the fixing device according to the present invention. FIG. 4B is a schematic configuration diagram illustrating an example of a film thickness adjusting unit and a foamy fixing solution applying unit in the fixing device according to the present invention. FIG. 5A is a schematic diagram showing a state of film thickness adjustment on a coating roller of a foamy fixing solution using a film thickness adjusting blade. FIG. 5B is a schematic diagram showing a state of film thickness adjustment on the application roller of a foam-like fixing solution using a film thickness adjusting blade. FIG. 6 is a schematic configuration diagram showing the configuration of the fixing device according to the embodiment of the present invention. FIG. 7 is a schematic configuration diagram showing another configuration of the fixing device according to the embodiment of the present invention. FIG. 8 is a schematic diagram showing another configuration of the fixing device according to the embodiment of the present invention. FIG. 9A is a schematic diagram showing an example of the configuration of the image forming apparatus of the present invention. FIG. 9B is a schematic diagram illustrating an example of the configuration of the image forming apparatus of the present invention. FIG. 10A is a schematic cross-sectional view illustrating an offset state generated in a conventional fixing device. FIG. 10B is a schematic cross-sectional view showing the state of offset generated in the conventional fixing device. FIG. 11 is an explanatory diagram showing a contact angle when a fixing solution is dropped onto the toner resin layer. FIG. 12 is a diagram showing a change in contact angle over time from the time when the fixing solution is brought into contact with the toner resin layer.

(Fixing solution)
The fixing solution of the present invention is a fixing solution for fixing resin fine particles such as toner to a recording medium, and includes a diluent containing water, a foaming agent that makes the fixing solution foamy, and at least a part of the resin fine particles. Contains a plasticizer that is softened by dissolution or swelling, and a wettability improver that improves wettability to the resin fine particles, and further contains a viscosity modifier, a solubilizer, and other components as necessary. .

<Diluent>
The diluent contained in the fixing solution according to the present invention is not particularly limited as long as it contains water. For example, water, an aqueous solvent obtained by adding an alcohol or the like to water, and the like are preferable. As water, for example, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used.

  When an aqueous solvent is used as the diluent, a surfactant may be added, and it is particularly preferable that the surface tension of the fixing solution is 20 mN / m to 30 mN / m. Examples of the alcohols include unitary alcohols such as cetanol; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, diethylene glycol, and the like in terms of enhancing the stability of bubbles in the foam-like fixing solution and making it difficult to break bubbles. Polyhydric alcohols such as propylene glycol, tripropylene glycol, 1,3-butylene glycol and glycerin are preferred. By containing these unit prices or polyhydric alcohols, it is effective in preventing curling of media such as paper.

  The diluent preferably contains an oil component to form an O / W emulsion or a W / O emulsion for the purpose of improving permeability and preventing curling of a medium such as paper. As this oil component, various known materials can be used. In the case of a diluent containing an oil component, an emulsion may be formed by using a dispersant, and various known materials can be used as the dispersant used to form this emulsion, but sorbitan monooleate And sorbitan fatty acid esters such as sorbitan monosterate and sorbitan sesquiolate, and sucrose esters such as sucrose laurate and sucrose stearate are preferred.

  The method for dispersing the fixing solution in the form of an emulsion using the dispersant is not particularly limited, and various known methods may be used. For example, a mechanical stirring means such as a homomixer or a homogenizer using rotating blades and a means for applying vibration such as an ultrasonic homogenizer can be mentioned. Of these, a method of applying a strong shear stress to the softening agent in the fixing solution is preferable.

<Foaming agent>
The foaming agent contained in the fixing solution according to the present invention is not particularly limited as long as it can foam the fixing solution, and can achieve excellent foaming properties and foam stability. Examples of foaming agents include saturated or unsaturated fatty acid salts, monoalkyl sulfates, sulfonates such as alkyl polyoxyethylene sulfates, alkyl polyoxyethylene sulfates or alkylbenzene sulfonates, or monoalkyl phosphates. Anionic surfactants such as phosphates.

-Fatty acid salt-
Among the foaming agents, fatty acid salts are most excellent in foam stability and are most suitable as foaming agents for fixing solutions.

  The fatty acid salt is preferably a fatty acid sodium salt, a fatty acid potassium salt or a fatty acid amine salt, more preferably a fatty acid amine salt. The method for producing these fatty acid salts is not particularly limited. For example, by heating water, adding a fatty acid, then adding triethanolamine, and heating the mixture with stirring for a certain period of time to cause a saponification reaction. It may be manufactured. At this time, by increasing the molar ratio of fatty acid to triethanolamine within the range of 1: 0.5 to 1: 0.9 and the fatty acid ratio, unreacted fatty acid remains after saponification, and the fixing solution Fatty acid and fatty acid amine salt can be mixed therein. The same is possible with sodium and potassium salts.

  The unsaturated fatty acid salt that can be used as the foaming agent is not particularly limited, but is preferably an unsaturated fatty acid salt having 18 carbon atoms and 1 to 3 double bonds. Specific examples include oleate, linoleate and linolenate. Since the reactivity is strong when the double bond is 4 or more, the stability of the fixing solution is poor. You may use the unsaturated fatty acid salt by these unsaturated saturated fatty acids individually by 1 type or in mixture of 2 or more types as a foaming agent. Further, the above saturated fatty acid salt and unsaturated fatty acid salt may be mixed and used as a foaming agent.

  The liquid plasticizer has a strong antifoaming effect, and as the concentration of the liquid plasticizer increases in the fixing solution, the foaming property and foam stability of the fixing solution deteriorate, and it is difficult to foam, and the bubbles break immediately. Therefore, it may be impossible to obtain a foam-like fixing solution having a low foam density.

  Therefore, in order to eliminate the deterioration of foaming properties when the concentration of the liquid plasticizer in the fixer is increased, various prototypes were made using the type and concentration of anionic surfactant as factors. By using a fatty acid salt having 12 to 18 carbon atoms as a foaming agent and further containing a fatty acid having 12 to 18 carbon atoms in the fixing solution, the foaming property of the fixing solution can be improved even when the concentration of the liquid plasticizer increases. Found no deterioration. Thereby, a stable foamy fixing solution can be provided.

  Here, in the foaming agent contained in the fixing solution, the number of carbon atoms of the fatty acid salt is preferably 12 to 18 in that the foaming property is superior to the case of simply foaming water. . Specifically, laurate (12 carbon atoms), myristic acid salt (14 carbon atoms), pentadecyl acid (15 carbon atoms), palmitate (16 carbon atoms), margaric acid (17 carbon atoms), stearic acid And a salt (carbon number 18).

  The action of the fatty acid used together with the fatty acid salt used as the foaming agent and the liquid plasticizer will be described. When an ester compound is used as the liquid plasticizer, the ester compound has an ester group in the chemical structure, and the fatty acid has a carbonyl group in the chemical structure. From this point, the ester group of the liquid plasticizer and the carbonyl group of the fatty acid show an electrical action in the fixing solution system, and this causes a binding action between molecules, and foams as a characteristic of the fixing solution. It is thought to improve the property and foam stability.

  In the fatty acid salt having 12 to 18 carbon atoms that can be used as the foaming agent, the smaller the number of carbons, the better the foaming property, but the foam stability is poor, and the higher the number of carbons, the foaming property is not so good. Excellent stability. Therefore, a single fatty acid salt may be used as the fatty acid salt, but it is more preferable to mix a plurality of fatty acid salts having 12 to 18 carbon atoms and having different carbon numbers. As a mixing ratio, it is preferable to contain the most myristate (carbon number 14) and to lower the ratio of laurate (carbon number 12) and stearate. More specific fatty acid salt ratios are 0: 6: 3: 1, 0: 4: 3: 1, 1: 5 by mass ratio of laurate: myristate: palmitate: stearate. : 3: 1, 1: 4: 4: 1, etc. are suitable.

  The content of the foaming agent is preferably 0.1% by mass to 20% by mass and more preferably 0.5% by mass to 10% by mass with respect to the mass of the fixing solution. When the content is less than 0.1% by mass, the foaming property may be insufficient. When the content is more than 20% by mass, the viscosity of the fixing solution increases, and the foaming property may decrease. is there.

  By containing a fatty acid having the same carbon number as the foaming agent fatty acid salt in the fixing solution, foamability and foam stability can be maintained even when the concentration of the liquid plasticizer increases. If the concentration of the liquid plasticizer is less than 10% by mass, there is no problem in foaming properties even if no fatty acid is contained. However, when the concentration of the liquid plasticizer is 10% by mass or more, particularly when the concentration of the liquid plasticizer is 30% by mass or more, the fatty acid salt hardly foams and the foamability may deteriorate. Even when the foamability is deteriorated, the foamability can be maintained by containing a fatty acid having the same carbon number as that of the fatty acid salt.

  However, if the content of the fatty acid is too large, the ratio of the fatty acid salt that is a foaming agent is lowered, and foamability may be deteriorated again. In such a case, the number of moles of the fatty acid salt may be equal to or greater than the number of moles of the fatty acid, and the ratio of the fatty acid to the fatty acid salt is 5: 5 to 1: 9. It is good also as a range.

  In addition to the combination of a fatty acid having the same carbon number and a fatty acid salt, for example, the fatty acid salt is amine myristate and the fatty acid is stearic acid, or the fatty acid salt is potassium palmitate and the fatty acid is stearic acid. Like a combination, the carbon number may be a combination of different fatty acid salts and fatty acids in the range of 12-18. By containing a fatty acid having a carbon number in the range of 12 to 18 in the fixing solution, even if a high concentration liquid plasticizer is contained, the foamability is not deteriorated, the foam stability is excellent, and the foaming is extremely low in density. Is possible.

  In addition, in order to prevent deterioration of the foaming property, other anionic surfactant (for example, alkyl ether sulfate (AES)) is used as a foaming agent, and further contains a fatty acid having 12 to 18 carbon atoms. May be.

  Further, the nonionic surfactant used in the fixing solution is not particularly limited, but alkyl glycoside having an alkyl group having 12 to 18 carbon atoms such as decyl glucoside and lauryl glucoside, and polyoxyethylene lauryl ether acetic acid. Examples thereof include sodium, sodium polyoxyethylene myristyl ether acetate, sodium polyoxyethylene palmityl ether acetate, and two or more of them may be used in combination. When the number of carbon atoms is less than 12 or more than 18, the foamability may be lowered.

  The amphoteric surfactant used in the fixing solution is not particularly limited, but fatty acid amidopropyldimethylaminoacetic acid betaines derived from fatty acids having 12 to 18 carbon atoms such as amidopropyldimethylaminoacetic acid betaine myristate; stearyl Alkyldimethylaminoacetate betaine having an alkyl group having 12 to 18 carbon atoms such as betaine dimethylaminoacetate; N- having an acyl group having 12 to 18 carbon atoms such as sodium lauroyl sarcosine sodium, myrtoyl sarcosine sodium, palmitoyl sarcosine sodium Acyl sarcosine and salts thereof; N-acyl group having an acyl group having 12 to 18 carbon atoms such as sodium myristoyl glutamate, palm fatty acid sodium glutamate, coconut oil fatty acid acyl glutamic acid triethanolamine and the like Min acid and its salts, and the like, may be used in combination. When the number of carbon atoms is less than 12 or more than 18, the foamability may be lowered.

<Plasticizer>
There is no restriction | limiting in particular as said plasticizer, According to the objective, a solid plasticizer and a liquid plasticizer can be applied. Moreover, these plasticizers can be used in combination according to the purpose.

-Solid plasticizer-
The solid plasticizer is not particularly limited as long as it is solid at room temperature and is soluble in a diluent described later and can soften resin fine particles such as toner in a state dissolved in the diluent. . Here, “normal temperature” refers to a temperature achieved without heating or cooling, and is preferably 5 ° C. to 35 ° C. as defined in JIS Z8703, for example. If it is within this normal temperature range, the solid plasticizer is in a solid state. That is, in the fixing solution in the foam state, the solid plasticizer is in a molten state because it contains water, but is applied to the unfixed toner, penetrates into the toner, and further the moisture of the fixing solution penetrated into the toner. When the amount decreases due to vaporization or the like, the solid plasticizer changes to a solid state. In the present invention, attention is paid to the fact that the solid plasticizer changes to a solid state as described above, and by utilizing this characteristic, the toner hardness after application of the fixing solution is increased and the problem relating to tack is solved. In addition, the solid plasticizer exerts its plastic ability to fine resin particles under appropriate conditions at room temperature, and when it loses its plastic ability and becomes a solid state, it hardens itself and contributes to prevention of tack. ,preferable.

  The solid plasticizer preferably has, for example, a functional group having an affinity such as having a certain compatibility with resin fine particles that are to be fixed. The functional group having affinity here is preferably a case where the functional group contained in the molecule constituting the resin fine particle and the functional group contained in the solid plasticizer are the same, and between these functional groups. It has a functional group that can have a certain interaction. If the functional group contained in the solid plasticizer has a functional group that can interact with the molecules constituting the resin fine particles, the solid plasticizer enters between the molecules constituting the resin fine particles due to the interaction of these functional groups. As a result, a so-called polymer blend state is formed between the solid plasticizer and the resin fine particles, and the solid plasticizer is effective in softening or swelling at least part of the resin fine particles such as toner. Because. As a specific example, the solid plasticizer is polyethylene glycol, and the polyethylene glycol contains an ethylene oxide group. A corresponding resin fine particle corresponds to a combination containing an ethylene oxide group in the resin molecule. In such a case, an ethylene oxide group is contained in both the solid plasticizer and the resin fine particles, and this improves the compatibility, thereby producing an effect of increasing the compatibility between the two. On the other hand, this concept is based on having a functional group having an affinity for both the solid plasticizer and the resin fine particles, and thus is not limited to the ethylene oxide group. Other examples include a propylene oxide group. In addition, it also works effectively when a functional group contained in a known toner is contained in a solid plasticizer.

  Examples of the solid plasticizer include those that exhibit plastic ability under certain conditions in addition to the above-mentioned requirements. Examples include the following.

(1) Plastic ability is exhibited by dissolving in a diluent described later Part having ethylene oxide group: polyethylene glycol having a molecular weight of 1,000 to 2,000 (2) Dissolving in diluent However, the plastic ability is not exhibited, but the plastic ability is exhibited in the presence of a small amount of a liquid plasticizer described later. Part having an ethylene oxide group: Among polyethylene glycols, those having a molecular weight of 2,000 to 10,000 ( 3) Even if dissolved in a diluent, the plastic ability is not exhibited, but the plastic ability is exhibited by slight heating (for example, about 50 ° C. to 100 ° C.) Part having an ethylene oxide group: Among polyethylene glycols, Polyoxyethylene monoalkyl ethers having a molecular weight of 2,000 to 10,000: polyoxyethylene monolauryl Ether, polyoxyethylene mono cetyl ether, etc.

  When the molecular weight of the polyethylene glycol exemplified in the above (1) is less than 1,000, the fixed image may be melted depending on the surrounding environment, and when it exceeds 2,000, the solid state is no longer in the normal temperature state. There may be a case where a sufficient plasticizing ability cannot be exhibited in a fixer system that uses only a solid plasticizer and does not share an optional liquid plasticizer described later. Based on such technical significance, the molecular weight is preferably 1,000 to 2,000.

  When the molecular weight of the polyethylene glycol exemplified in the above (2) exceeds 10,000, it is no longer in a liquid state at room temperature, and thus a grain boundary may occur between resin fine particles as a fixing object. From this point of view, it is difficult to use when the molecular weight is 10,000 or more in a fixer system that uses only a solid plasticizer and does not share a liquid plasticizer, and the fixer contains water. When used in an embodiment, a molecular weight of 1,000 to 10,000 is a usable molecular weight.

  The heating temperature of the solid plasticizer exemplified in the above (3) is not particularly limited as long as the plastic ability can be exhibited, but is preferably 50 ° C to 100 ° C. If the heating temperature is less than 50 ° C., fixing may be insufficient, and if it exceeds 100 ° C., it is uneconomical in terms of energy consumption.

  Although there is no restriction | limiting in particular as content of a solid plasticizer, It is preferable that it is 5-30 mass% with respect to the mass of a fixing solution. When the content is less than 5% by mass, fixing becomes difficult. When the content exceeds 30% by mass, the viscosity of the fixing solution and the foamy fixing solution increases, and in addition, poor foaming and foam As a result, there is a problem in quality.

-Liquid plasticizer-
The fixing solution according to the present invention may further include a liquid plasticizer. There is no particular limitation as long as it is soluble in the above-described diluent and exhibits a plastic ability under a certain condition. For example, at least one of resin fine particles constituting a toner by exhibiting a plastic ability alone. The resin fine particles may be softened by dissolving or swelling the part, but the plastic ability may be exhibited by combining with the solid plasticizer. Examples of liquid plasticizers include ester compounds in that they are excellent in solubility or swelling under certain conditions. Among these ester compounds, an aliphatic ester or a carbonate ester is more preferable from the viewpoint that the softening ability of the resin is excellent or the degree of foaming inhibition by the diluent described later is low.

  The liquid plasticizer preferably has an acute oral toxicity LD50 of more than 3 g / kg, more preferably 5 g / kg or more, from the viewpoint of safety to the human body. As the liquid plasticizer, the above-mentioned aliphatic ester is particularly preferable because it is highly safe for the human body as often used as a cosmetic raw material.

  In addition, the fixing of the toner as the resin fine particles to the recording medium is performed by a device that is frequently used in a sealed environment, and the liquid plasticizer remains in the toner even after the fixing of the toner to the recording medium. The fixing of the toner to the recording medium is preferably not accompanied by generation of a volatile organic compound (VOC) and an unpleasant odor. In this respect, it is preferable that the liquid plasticizer does not contain a volatile organic compound (VOC) and a substance that causes an unpleasant odor. The aliphatic ester is more preferable in that it has a high boiling point, low volatility, and no irritating odor as compared to generally used organic solvents (toluene, xylene, methyl ethyl ketone, ethyl acetate, etc.).

  In addition, as a practical odor measurement scale that can measure odors in office environments with high accuracy, the odor index [10 × log (substance odor is felt by sensory measurement) The dilution factor of the substance until it disappears)] may be used as an indicator of odor. The odor index of the aliphatic ester contained in the liquid plasticizer is preferably 10 or less. In this case, an unpleasant odor is not felt in a normal office environment. Furthermore, it is preferable that not only the liquid plasticizer but also other liquids contained in the fixing solution have no unpleasant odor and irritating odor, as with the liquid plasticizer.

-Aliphatic ester-
The aliphatic ester is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include saturated aliphatic esters, aliphatic monocarboxylic acid esters, aliphatic dicarboxylic acid esters, and aliphatic dicarboxylic acid dialkoxys. It may be alkyl.

--Saturated aliphatic ester--
When the aliphatic ester is a saturated aliphatic ester, the storage stability (resistance to oxidation, hydrolysis, etc.) of the liquid plasticizer can be improved. Further, the saturated aliphatic ester has high safety to the human body, and many saturated aliphatic esters can dissolve or swell the resin contained in the toner in a short time such as within 1 second. Furthermore, saturated aliphatic esters can reduce the tackiness of the toner provided on the recording medium. This is presumably because the saturated aliphatic ester forms an oil film on the surface of the dissolved or swollen toner.

In the fixing solution according to the present invention, preferably, the general formula of the saturated aliphatic ester may be a compound represented by R ¹ COOR ² , wherein R ¹ has 11 to 14 carbon atoms. An alkyl group, and R ² is a linear or branched alkyl group having 1 to 6 carbon atoms. If the number of carbon atoms of R ¹ and R ² is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability is lowered. That is, the saturated aliphatic ester is a compound represented by the general formula R ¹ COOR ² , R ¹ is an alkyl group having 11 to 14 carbon atoms, and R ² is 1 or more carbon atoms. In the case of 6 or less linear or branched alkyl group, the solubility or swelling property with respect to the resin contained in the toner can be improved. Moreover, it is preferable that the odor index of the compound represented by the general formula R ¹ COOR ² is 10 or less in that it does not have an unpleasant odor and an irritating odor.

-Aliphatic monocarboxylic acid ester-
Examples of the aliphatic monocarboxylic acid ester include ethyl laurate, hexyl laurate, ethyl tridecylate, isopropyl tridecylate, ethyl myristate, and isopropyl myristate. Many of these aliphatic monocarboxylic acid esters are soluble in oily solvents but not in water. Therefore, when an aliphatic monocarboxylic acid ester is used to form a fixing solution composed of an aqueous solvent, glycols may be contained in the fixing solution as a solubilizing agent described later, and the solution may be dissolved or in the form of a microemulsion.

-Aliphatic dicarboxylic acid ester-
The aliphatic ester may be an aliphatic dicarboxylic acid ester. When the aliphatic ester is an aliphatic dicarboxylic acid ester, the resin fine particles contained in the toner can be dissolved or swollen in a shorter time. For example, in high-speed printing of about 60 ppm, it is preferable that the time until the fixing liquid is applied to the unfixed toner on the recording medium and the toner is fixed on the recording medium is within 1 second. When the aliphatic ester is an aliphatic dicarboxylic acid ester, the time required for fixing the toner to the recording medium by applying a fixing solution to the unfixed toner on the recording medium is within 0.1 seconds. It becomes possible to. Further, by adding a smaller amount of the liquid plasticizer, the resin fine particles contained in the toner can be dissolved or swollen, so that the content of the liquid plasticizer contained in the fixing liquid can be reduced.

In the fixing solution according to the present invention, preferably, the general formula of the aliphatic dicarboxylic acid ester is a compound represented by R ³ (COOR ⁴ ) ₂ , wherein R ³ is an alkylene having 3 to 8 carbon atoms. R ⁴ may be a linear or branched alkyl group having 3 to 5 carbon atoms. If the number of carbon atoms in R ³ and R ⁴ is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability decreases.

The aliphatic dicarboxylic acid ester is a compound represented by the general formula R ³ (COOR ⁴ ) ₂ , wherein R ³ is an alkylene group having 3 to 8 carbon atoms, and R ⁴ has 3 or more carbon atoms. In the case of a linear or branched alkyl group of 5 or less, the solubility or swelling property with respect to the resin fine particles contained in the toner can be improved. In addition, the odor index of the compound represented by the general formula R ³ (COOR ⁴ ) ₂ is preferably 10 or less from the viewpoint of having no unpleasant odor and irritating odor.

  Examples of the aliphatic dicarboxylic acid ester include 2-ethylhexyl succinate, dibutyl adipate, diisobutyl adipate, diisopropyl adipate, diisodecyl adipate, diethyl sebacate, and dibutyl sebacate. Many of these aliphatic dicarboxylic acid esters are soluble in oily solvents but not in water. For this reason, when an aliphatic dicarboxylic acid ester is used to form a fixing solution composed of an aqueous solvent, glycols may be contained in the fixing solution as a solubilizing agent described later, and the solution may be in the form of a solution or a microemulsion.

-Dialkoxyalkyl aliphatic dicarboxylate-
Furthermore, in the fixing solution according to the present invention, the aliphatic ester is preferably a dialkoxyalkyl aliphatic dicarboxylate. When the aliphatic ester is an aliphatic dicarboxylate dialkoxyalkyl, the fixing property of the toner to the recording medium can be improved.

In the liquid plasticizer contained in the fixing solution according to the present invention, the aliphatic dicarboxylic acid dialkoxyalkyl is a compound represented by the general formula R ⁵ (COOR ⁶ —O—R ⁷ ) ₂ , wherein R ⁵ is the number of carbon atoms. Is an alkylene group having 2 to 8 carbon atoms, R ⁶ is an alkylene group having 2 to 4 carbon atoms, and R ⁷ may be an alkyl group having 1 to 4 carbon atoms. If the number of carbon atoms of R ⁵ , R ⁶ and R ⁷ is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability is lowered.

The aliphatic dicarboxylic acid dialkoxyalkyl is a compound represented by the general formula R ⁵ (COOR ⁶ —O—R ⁷ ) ₂ , wherein R ⁵ is an alkylene group having 2 to 8 carbon atoms, R ⁶ is an alkylene group having 2 or more and 4 or less carbon atoms, and R ⁷ is an alkyl group having 1 or more and 4 or less carbon atoms, it can improve the solubility or swelling property with respect to the resin contained in the toner. it can. In addition, the odor index of the compound represented by the general formula R ⁵ (COOR ⁶ —O—R ⁷ ) ₂ is preferably 10 or less from the viewpoint of having no unpleasant odor and irritating odor.

  Examples of the aliphatic dicarboxylic acid dialkoxyalkyl include diethoxyethyl succinate, dibutoxyethyl succinate, dicarbitol succinate such as fatty acid dicarbitols, dimethoxyethyl adipate, diethoxyethyl adipate, dibutoxyethyl adipate, sebacine Examples include diethoxyethyl acid. When these aliphatic dicarboxylic acid dialkoxyalkyls are used in an aqueous solvent, glycols are included in the fixing solution as a dissolution aid, if necessary, to form a solution or microemulsion.

  Examples of ester compounds other than those described above include glycerol 1,2-carbonate, 4-methoxymethyl-1,3-dioxolan-2-one, and the like as carbonate esters that are examples of liquid plasticizers.

  Moreover, for example, citric acid esters such as triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate and the like can be mentioned.

Also, as a saturated aliphatic carboxylic acid esters of saturated fatty alcohols of the general formula ^{R 8 (COOR 9 OR 10 OR} 11) 2
(Wherein R ⁸ is an alkylene group having 2 to 8 carbon atoms, R ⁹ and R ¹⁰ are each independently an alkylene group having 2 or 3 carbon atoms, and R ¹¹ is an alkylene group having 2 or 3 carbon atoms. A diester represented by 1 to 4 alkyl groups). When this is used, the resin particles can be dissolved or swollen in a shorter time. Specifically, when the resin particles are toner, in high-speed printing of about 60 ppm, the time until the toner image is fixed after the fixing liquid is applied to the unfixed toner image formed on the recording medium is reduced to 0. It can be done within 1 second. Furthermore, the content of the softening agent in the fixing solution can be reduced. At this time, when the carbon number of R ⁸ is 1, when the carbon number of R ⁹ is 1, and when the carbon number of R ¹⁰ is 1, the odor index may exceed 10. On the other hand, when the carbon number of R ⁸ exceeds ^8, the carbon number of R ⁹ exceeds 3, the carbon number of R ¹⁰ exceeds 3, and the carbon number of R ¹¹ exceeds 4, The ability to dissolve or swell may be reduced.

  Examples of such diesters include, but are not limited to, diethoxyethoxyethyl succinate, dimethoxyethoxyethyl succinate, dimethoxyethoxyethyl adipate, diethoxyethoxyethyl sebacate and the like, and two or more of them may be used in combination. .

Furthermore, as an ester of a saturated aliphatic carboxylic acid and a saturated aliphatic alcohol, the general formula R ¹² (OCOR ¹³ ) ₂
(In the formula, R ¹² is an alkylene group having 2 to 8 carbon atoms, and R ¹³ is a linear or branched alkyl group having 2 to 5 carbon atoms.)
The diester represented by these is preferable. When this is used, the resin particles can be dissolved or swollen in a shorter time. Specifically, when the resin particles are toner, in high-speed printing of about 60 ppm, the time until the toner image is fixed after the fixing liquid is applied to the unfixed toner image formed on the recording medium is reduced to 0. It can be done within 1 second. Furthermore, the content of the softening agent in the fixing solution can be reduced. At this time, when the carbon number of R ¹² is 1 and when the carbon number of R ¹³ is 1, the odor index may exceed 10. On the other hand, when the carbon number of R ¹² exceeds 8, and when the carbon number of R ¹³ exceeds 5, the ability to dissolve or swell the resin particles may decrease.

  Examples of such diesters include, but are not limited to, ethylene glycol diacetate, ethylene glycol dipropionate, propylene glycol diacetate, propylene glycol dibutyrate, butylene glycol dibutyrate and the like, and two or more of them may be used in combination. .

Also, as a saturated aliphatic carboxylic acid esters of saturated fatty alcohols of the general formula _{^{R 14 (OR 15 OCOR 16)}} 2
(In the formula, R ¹⁴ is an alkylene group having 2 to 4 carbon atoms, R ¹⁵ is a linear or branched alkylene group having 2 or 3 carbon atoms, and R ¹⁶ has a carbon number. A diester represented by 1 to 4 alkyl groups). When this is used, the resin particles can be dissolved or swollen in a shorter time. Specifically, when the resin particles are toner, in high-speed printing of about 60 ppm, the time until the toner image is fixed after the fixing liquid is applied to the unfixed toner image formed on the recording medium is reduced to 0. It can be done within 1 second. Furthermore, the content of the softening agent in the fixing solution can be reduced. At this time, when the carbon number of R ¹⁴ is 1 and when the carbon number of R ¹⁵ is 1, the odor index may exceed 10. On the other hand, when the carbon number of R ¹⁴ exceeds 4, when the carbon number of R ¹⁵ exceeds 3, and when the carbon number of R ¹⁶ exceeds 4, the ability to dissolve or swell resin particles may decrease. .

  Such a diester is not particularly limited, and examples thereof include triethylene glycol diacetate, triethylene glycol dipropionate, and tripropylene glycol diacetate, and two or more of them may be used in combination.

As carbonate ester of divalent saturated aliphatic alcohol, general formula
(In the formula, R ¹⁷ is an alkylene group.)
The compound represented by these is preferable. When this is used, the resin particles can be dissolved or swollen in a short time. Specifically, when the resin particles are toner, in high-speed printing of about 60 ppm, the time from when the fixing solution is applied to the unfixed toner image formed on the recording medium until the toner image is fixed is 1 Can be within seconds. Further, such carbonate ester can reduce the stickiness of the toner image. This is considered to be because the carbonic ester forms an oil film on the surface of the dissolved or swollen toner image.

  Such a carbonate ester is not particularly limited, and examples thereof include ethylene carbonate, propylene carbonate, butylene carbonate, and two or more of them may be used in combination.

  The content of the liquid plasticizer is preferably 0.5% by mass to 50% by mass and more preferably 5% by mass to 40% by mass with respect to the mass of the fixing solution. If the content is less than 0.5% by mass, the effect of dissolving or swelling the resin fine particles contained in the toner may be insufficient, and if it exceeds 50% by mass, it will be included in the toner for a long time. There is a possibility that the fluidity of the resin cannot be lowered and the fixing toner layer has adhesiveness.

<Wettability improver>
The wettability improving agent is not particularly limited as long as the wettability of the fixing solution is improved when the wettability improving agent is added to the fixing solution to which the wettability improving agent is not added. However, from the viewpoint of improving wettability, it is preferable to have a functional group having an affinity for the resin fine particles.
The functional group is preferably an ester group, and the wettability improving agent is preferably a compound having an ester group in the molecule.
Such a compound is not particularly limited, but an alcohol alkoxylate is particularly preferable. The fixer using the alcohol alkoxylate has drastically improved wettability, and can prevent offset while keeping the amount of fixer applied to a small amount during high-speed printing.
Examples of commercially available alcohol alkoxylates include BYK-DYNWET 800 (manufactured by Big Chemie Japan Co., Ltd.).

<Viscosity modifier>
There is no restriction | limiting in particular as said viscosity modifier, According to the objective, it can select suitably, For example, polyethyleneglycol etc. are preferable. Although there is no restriction | limiting in particular as content in the said fixing liquid of the said viscosity modifier, It is preferable to adjust suitably with the kind and molecular weight of a viscosity modifier, for example, if it is polyethyleneglycol of molecular weight 6,000, 1 mass-20 mass % Is preferable, and 3 to 10% by mass is particularly preferable.
When the content is less than 1% by mass, a sufficient viscosity adjusting effect may not be obtained, and when it exceeds 20% by mass, foamability may be deteriorated.

<Solubilizer>
There is no restriction | limiting in particular as said solubilizer, According to the objective, it can select suitably, For example, polyhydric alcohol is mentioned.
Examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butylene glycol, and glycerin. Among these, propylene glycol, dipropylene glycol, and tripropylene glycol are preferable in that the liquid plasticizer can be dissolved even at a high concentration and does not deteriorate the foamability of the foaming agent.
The content of the solubilizer in the fixing solution is not particularly limited, but is preferably 3% by mass to 20% by mass, and more preferably 5% by mass to 15% by mass.
When the content is less than 3% by mass, a sufficient solubilizing effect may not be obtained, and when it exceeds 20% by mass, foamability may be reduced.

<Other ingredients>
-Foaming agent-
The fixing solution according to the present invention is foamed and used as a below-described foam fixing solution for fixing resin fine particles, and penetrates while pressing the foam fixing solution into a fine particle layer such as toner at a coating contact nip portion. When bubbles are broken, the penetration is inhibited. Therefore, the fixing solution according to the present invention may further include a foaming agent for the purpose of suppressing such a phenomenon and improving foam stability. The foaming agent is not particularly limited, but is preferably a fatty acid alkanolamide, and more preferably a fatty acid alkanolamide (1: 1) type in terms of foam stability. The content of the foam increasing agent is preferably 0.01% by mass to 3% by mass with respect to the mass of the fixing solution.

<Resin fine particles>
In the present invention, the resin fine particle is not limited in its configuration and material as long as it is in the form of fine particles made of resin. The resin fine particles may constitute various toners for electrophotography or the like, and may be resin fine particles containing a conductive member.

  Of the resin fine particles, the toner used in the electrophotographic process has the highest fixing effect in combination with the fixing solution of the present invention.

  In the present invention, the toner is not particularly limited as long as it has fine resin particles. For example, the toner contains a colorant, a charge control agent, a binder resin, and a release agent, and further contains other agents as necessary. You may contain a component.

  There is no restriction | limiting in particular as said coloring agent, According to the objective, it can select suitably from well-known dyes and pigments.

  The charge control agent is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, triphenylmethane dye, molybdate chelate pigment, rhodamine dye, alkoxy amine, quaternary ammonium Examples thereof include salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus alone or a compound thereof, tungsten alone or a compound thereof, fluorine-based activator, metal salt of salicylic acid, metal salt of salicylic acid derivative, and the like. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, a polystyrene resin, a styrene-acryl copolymer, a polyester resin etc. are mentioned. Among these, a polyester resin having an ethylene oxide group or a propylene oxide group is preferable. Among these, as the polyester resin having an ethylene oxide group, a polyol polyester resin is more preferable from the viewpoint of affinity with the fixing solution. When the polyester resin has these substituents, if the solid plasticizer has a functional group having an affinity for these substituents, the resin of the toner is caused by the interaction between the functional group of the ester resin and the substituent of the solid plasticizer. As a result, a solid plasticizer enters between the molecules constituting the toner, and as a result, a so-called polymer blend state is formed between the solid plasticizer and the resin, and the solid plasticizer forms at least a part of resin fine particles such as toner. This is considered to be effective when softening or swelling.

  The release agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include wax components such as carnauba wax and polyethylene wax.

  The other components are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include external additives, fluidity improvers, cleaning improvers, magnetic materials, metal soaps, and the like. .

  Further, the toner is preferably subjected to water repellency treatment by fixing hydrophobic fine particles such as hydrophobic silica having a methyl group and hydrophobic titanium oxide to the surface of the toner particles.

<Contact angle>
In the fixing solution of the present invention, the contact angle with respect to the unfixed resin layer formed of the resin fine particles is 40 degrees or less within 0.3 seconds from the time when the fixing solution contacts the resin layer. One of the features.
As a result, it is possible to obtain a fixing solution capable of preventing an offset while keeping the amount of the fixing solution applied to a small amount even during high-speed printing. If the contact angle does not become 40 degrees or less within 0.3 seconds, an offset may occur during high-speed printing or when the adhesion amount of the fixing liquid is reduced.

The contact angle is a dynamic contact angle (change in contact angle with time) by a so-called droplet method, and can be measured with a commercially available dynamic contact angle meter. This dynamic contact angle is one measure representing the wettability of a liquid with respect to a solid. Generally, the better the wettability, the smaller the contact angle. That is, it can be said that the greater the change in the contact angle, the better the wettability.
In general, the lower the surface tension and viscosity of the liquid, the better the wettability. However, as a result of extensive studies by the inventors, the wettability does not necessarily depend only on the surface tension and viscosity, and the surface is more stable than other fixing liquids. It has been found that there are fixers that exhibit good wettability despite high tension and viscosity.
When a fixing solution having excellent wettability is used, the permeation time for the resin fine particles can be shortened. This penetration time is a major factor that determines whether or not the toner is offset during fixing. If nip time> penetration time, offset occurs. This principle is as follows.

That is, when the foamy fixing solution passes through the toner layer and reaches the base, a binding force is generated between the toner particles and between the toner particles and the base due to the surface tension of the fixing solution. Since it is aqueous, the bonding force between the foam-like fixing solution applying means and toner particles is small. For this reason, the toner particles are not offset to the foam-like fixing solution applying means even if the foam-like fixing solution providing means is separated.
However, if the foam fixing solution applying means is separated before the foam fixing solution reaches the ground, the toner is offset to the foam fixing solution applying means because there is a dry portion between the toner particles and the bonding force there is weak. To do. Therefore, in order to prevent offset, the nip time must be longer than the penetration time.
Therefore, since the nip time is shortened during high-speed printing, it is necessary to further shorten the penetration time.

Further, the bulk density of the foam and the fixing solution and the coating amount on the recording medium and the toner layer are closely related to each other. The higher the foam density, the larger the coating amount. When the coating amount is large, a feeling of residual liquid may occur on the recording medium. Therefore, when the recording medium is paper, the application amount per A4 paper is preferably 50 mg to 100 mg.
In order to reduce the coating amount of the fixing solution, it is necessary to reduce the thickness of the foam film on the foam-like fixing solution application means described later or to reduce the foam density. However, the thickness of the foam film is smaller than that of the toner layer. If the thickness is not increased, the permeation time may become extremely long or the permeation may not be achieved. Therefore, considering that the maximum thickness of the toner layer is 30 μm to 40 μm in a full-color image, the lower limit is about 50 μm. Therefore, it is necessary to lower the bubble density to reduce the coating amount.
If the foam fixing solution on the foam fixing solution applying means is all applied to the recording medium, the foam density is approximately 0. 0 when the coating amount is 100 mg or less when the foam film thickness is 50 μm. Must be 04 g / cm ³ or less.

Moreover, it was found that the bubble density has a great influence on the permeation time, and the lower the bubble density, the longer the permeation time.
From the above, in order to perform fixing with a low coating amount during high-speed printing, it is necessary to use a fixing solution having a small contact angle with respect to the toner layer.
In particular, at high-speed printing with a paper transport speed of 300 mm / sec, in order to stably fix the coating amount to 100 mg or less, the contact angle needs to be 40 degrees or less within 0.3 seconds.

<Foamization>
The fixing solution according to the present invention is used after being foamed by a fixing method described later. Foam fixer is preferably a bulk density of ^{0.01g / cm 3 ~0.1g / cm 3} , more preferably ^{0.01g / cm 3 ~0.05g / cm 3} , 0. 025 g / cm ^{3 to} 0.05 g / cm ³ is particularly preferable. When the bulk density is less than 0.01 g / cm ³ , the application of the fixing solution may be insufficient. When the bulk density exceeds 0.1 g / cm ³ , there is a residual liquid feeling on the recording medium when the fixing solution is applied. May occur.
The foamed fixing solution preferably has a bubble diameter of 5 μm to 50 μm, more preferably 10 μm to 30 μm. Thereby, the foamed fixing liquid can be applied to the resin-containing particles without disturbing the resin-containing particles having a particle diameter of 5 μm to 10 μm formed on the medium.

<Recording medium>
In the present invention, the recording medium is not particularly limited as long as it can fix resin fine particles constituting toner or the like. Among these, the recording medium is preferably a medium having permeability to the fixing solution, and in the case where the medium substrate does not have liquid permeability, a medium having a liquid-permeable layer on the substrate is preferable. There is no restriction | limiting in particular as a form of a recording medium, The solid thing which has a plane and a curved surface other than a sheet form may be sufficient. For example, it may be one (so-called varnish coat) in which transparent resin fine particles are uniformly fixed on a medium such as paper to protect the paper surface. The material of the recording medium is not particularly limited and can be appropriately selected according to the purpose. For example, a plastic film such as a sheet for OHP having a general fiber constituting a paper, a cloth, a liquid permeable layer, or the like. , Metals, resins, and ceramics.

(Fixing method and fixing device)
The fixing method according to the present invention includes a foam fixing solution generation step, a film thickness adjustment step, and a foam fixing solution application step, and further includes other steps as necessary.

  The fixing device according to the present invention includes a foamy fixing solution generating unit, a foaming fixing solution applying unit, and a film thickness adjusting unit, and further includes other units as necessary.

  The fixing method according to the present invention can be preferably carried out by the fixing device according to the present invention, the foamy fixer generating step can be performed by a foamy fixer generating means, and the film thickness adjusting step is a film thickness adjusting step. The foaming fixer applying step can be performed by a foamy fixer applying unit, and the other steps can be performed by the other units.

<Foam Fixer Generation Step and Foam Fixer Generation Unit>
The foamy fixer generating step is a step of generating a foamy fixer by foaming the fixer according to the present invention, and is performed by a foamy fixer generating unit.

  In the present invention, as shown in FIG. 1, the fixing liquid is changed to a foam-like fixing liquid 14 composed of foam by the foam-like fixing liquid generating means, so that the bulk density of the fixing liquid can be lowered and the coating roller 11 can be used. Since the fixing liquid layer can be thickened and the influence of the surface tension of the fixing liquid can be suppressed, offset of resin fine particles to the application roller 11 can be prevented.

  Here, the state of the offset generated in the conventional fixing device will be described with reference to the drawings. 10A and 10B are schematic views showing an offset state generated in the conventional fixing device, and FIG. 10B is a partially enlarged view of FIG. 10A. Referring to these figures, when the fixing liquid layer 84 is in a liquid form, a strong surface tension acts on the liquid surface of the fixing liquid layer 84 on the application roller 81 along the roller surface. Furthermore, an internal flow is generated in the fixing liquid layer on the application roller 81 in the moving direction of the application roller. For this reason, when the thickness of the fixing liquid layer on the application roller 81 is a thin layer that is equal to or less than that of the toner layer, the surface tension works so as to pull the unfixed toner layer 83 onto the surface of the application roller 81, Further, the internal flow also works to carry the toner along the surface of the application roller, so that the unfixed toner adheres / adheres to the application roller 81 and a toner offset occurs. When the fixing liquid layer on the application roller 81 is more than twice as thick as the toner layer, the influence of the surface tension and internal flow of the liquid is less likely to affect the toner. , Toner offset is reduced. On the contrary, it means that for the uniform application in which the resin fine particles are not offset, the fixing liquid layer needs to be thickened to some extent on the surface of the application roller 81. On the other hand, the smaller the amount of the fixing solution on the resin fine particle layer on the coated medium, the better the fixing responsiveness, the residual liquid feeling and the curling prevention, which means that it is desirable that the weight of the fixing solution is small. In order to satisfy the condition that the thickness of the fixing solution layer is thick and the volume of the fixing solution is large and the weight of the fixing solution on the medium after coating is small, the density of the fixing solution should be low and At most, the substantial coating weight can be reduced.

  In the present invention, by adopting the above-described configuration, for example, as shown in FIG. 1, offset of resin fine particles during fixing can be prevented.

  In the fixing method and fixing device according to the present invention, the foamy fixing solution generating step and the foaming fixing solution generating means may be any one that can generate a foamed fixing solution by foaming the fixing solution according to the present invention. There is no particular limitation. One mode thereof will be described with reference to FIG.

  FIG. 3 is a schematic view showing the configuration of the foamy fixing solution generating means in the fixing device according to the present invention. 3 includes a fixer container 31 that stores the liquid fixer 32 such as the fixer according to the present invention, a liquid transport pipe 34 that transports the liquid fixer 32, and a liquid. A transport pump 33 that obtains driving for transport, a gas / liquid mixing unit 35 that mixes gas and liquid, and a foam generation unit 38 that foams the liquid fixer 32 to obtain a desired foamy fixer. Have.

  The liquid fixing liquid 32 stored in the fixing liquid container 31 is transported through the liquid transport pipe 34 by the driving force of the transport pump 33 and sent to the gas / liquid mixing unit 35. The transport pump is not particularly limited as long as it can transport the liquid fixing solution, and there are a gear pump, a bellows pump, and the like, but a tube pump is preferable. If there is a vibration mechanism or a rotation mechanism such as a gear pump, the fixer bubbles in the pump, and the fixer may be compressible, resulting in a decrease in conveying ability. In addition, the above-mentioned mechanical parts or the like may contaminate the fixer or conversely deteriorate the mechanical parts. On the other hand, since the tube pump is a mechanism that pushes out the liquid in the tube while deforming the tube, the only member in contact with the fixing liquid is the tube. By using a member that has liquid resistance to the fixing liquid, No contamination or deterioration of pump system parts. In addition, since the tube is only deformed, the liquid does not foam, and the conveyance capacity can be prevented from being lowered.

  The gas / liquid mixing unit 35 is provided with an air port 36, and a negative pressure is generated in the air port 36 along with the flow of the liquid, and the gas is introduced from the air port 36 into the gas / liquid mixing unit 35. Are mixed. Furthermore, by passing through the microporous sheet 37, a large bubble having a uniform bubble diameter can be generated. The pore diameter is preferably 30 μm to 100 μm. The porous member is not limited to the microporous sheet 37 in FIG. 3, and may be a porous member having a continuous foam structure, and may be a sintered ceramic plate, a nonwoven fabric, or a foamed resin sheet having a pore diameter of 30 μm to 100 μm. As another method for generating large bubbles, the liquid fixer supplied from the above-described transport pump and the air from the air port are stirred with a blade-like stirrer, and large bubbles are generated while bubbles are involved in the liquid. A configuration in which a large bubble is generated by bubbling the liquid fixing solution supplied from the above-described transport pump with an air supply pump or the like is also preferable.

  Next, the liquid fixer 32 mixed with air is sent to a bubble generating unit 38 that obtains a desired foamy fixer. In the foam generation unit 38, a shearing force is applied to the liquid fixer 32 mixed with air, and a large bubble is divided into two or more bubbles. The configuration of the foam generating unit 38 is not particularly limited as long as it can be performed in this way, but the closed cylinder is a closed double cylinder and the inner cylinder is rotatable, and is larger than a part of the outer cylinder. A configuration may be employed in which a foam-like fixer is supplied and a shear force is received by the rotating cylinder while passing through a gap between the inner rotating cylinder and the outer cylinder (this is a flow path). Due to this shearing force, the large bubbles are changed into minute bubbles, and a foam-like fixing liquid having a desired minute bubble diameter can be obtained from the outlet of the bubbles provided in the outer cylinder. In addition, a spiral groove may be provided in the inner cylinder to increase the liquid transport capability in the cylinder.

  The fixer only needs to be foamed when applied to a resin fine particle layer such as toner on a recording medium such as paper, and need not be foamed in the fixer container. In the fixing solution container, it is a liquid that does not contain air bubbles, and it is preferable to provide a means for forming a bubble in the liquid conveyance path until the liquid is supplied from the container or applied to the resin fine particle layer. This is because the fixing liquid container is a liquid, and the foamed structure after the liquid is taken out from the container has a great advantage that the container can be downsized.

  The fixing solution according to the present invention is foamed, and the thickness of the foamed fixing solution layer composed of the foamed fixing solution is described later with respect to the entire recording medium surface according to the thickness of the resin fine particle layer to be fixed. As described above, the adjustment is made on the surface of the foamy fixing solution applying means. For example, when resin fine particles constitute toner and color images and black and white characters are mixed on the recording medium, if the entire recording medium surface is applied with a foam-like fixing liquid layer of the same thickness, a thick toner layer such as a color photographic image In some cases, defective fixing or image omission may occur, or a partial defect may occur in which black and white character portions are sticky and the printed materials stick to each other. The cause of the problem will be described in detail below.

  In general, in the case of large bubbles of about 0.5 mm to 1 mm, bubbles can be generated relatively easily by simple stirring, etc., and the generation of large bubbles takes less than a few seconds (not longer than 0.1 seconds). can do. Therefore, paying attention to the fact that bubbles that are larger than the desired bubble diameter and that can be visually observed can be easily and quickly obtained, and from about 5 μm to 50 μm quickly from the large bubbles. As a result of diligently studying the method of generating microbubbles, dividing the large foam by applying shear force to the large foam is extremely quick compared to the method of generating microbubbles from the liquid state as described above. It has been found that microbubbles of a desired size can be generated. In this respect, the configuration of the foamy fixing solution generating unit 30 as described above is a preferable mode for realizing this.

  In this way, by combining a large bubble generating unit that changes the liquid fixing solution into a liquid having a large bubble diameter and a fine bubble generating unit that generates a small bubble by applying shear force to the large bubble, It is possible to generate a foamy fixing solution having a fine bubble diameter of 5 to 50 μm in a very short time.

  In particular, when the average particle size of the resin fine particles is about 5 μm to 10 μm, the foamy fixing solution 14 can be applied to the resin fine particle layer 13 without disturbing the resin fine particle layer 13 on the recording medium 12. The bubble diameter range is preferably 5 μm to 50 μm. As shown in FIG. 2, the foam-like fixing solution 20 composed of the bubbles 22 is composed of a liquid film boundary 21 that separates the bubbles 22.

<Film thickness adjusting step and film thickness adjusting means>
The film thickness adjusting step in the fixing method according to the present invention is a step of forming a foam-like fixing solution on the contact surface of the foam-like fixing solution applying means to a desired thickness, and is performed by the film thickness adjusting means.

  The film thickness adjusting means is not particularly limited as long as the foam fixing solution can be formed to a desired thickness on the contact surface of the foam fixing solution applying means, and can be appropriately selected according to the purpose. Examples include a blade for adjusting thickness, and a combination of a blade and a coating roller. Note that aspects of the film thickness adjusting step and the film thickness adjusting means will be described later.

<Foam Fixer Application Step and Foam Fixer Application Means>
The foaming fixer application step in the fixing method according to the present invention is a step of applying the foamy fixer formed in a desired thickness to the resin fine particle layer on the medium, and is performed by a foamy fixer application unit.

  4A and 4B are schematic configuration diagrams showing an example of a film thickness adjusting unit and a foamy fixing solution applying unit in the fixing device according to the present invention. The fixing device 40 of the present invention shown in FIG. 4A is a resin fine particle layer (resin fine particle layer made of resin fine particles constituting toner, etc.). The coating roller 41 for applying to the toner particle layer) and the film thickness of the desired fine foam foam-like fixing solution on the surface of the coating roller are adjusted according to the thickness of the unfixed toner layer on the recording medium. And a film thickness adjusting blade 42 which is a film thickness adjusting means for adjusting the optimal film thickness of the foamy fixing solution, and a pressure roller 43 at a position facing the application roller 41. A recording medium having unfixed toner (made of resin fine particles) on the surface passes through a nip portion composed of a coating roller 41 and a pressure roller 43. On the other hand, the thickness of the foam-like fixer generated by the foam-like fixer generating means 30 is adjusted by the film thickness adjusting blade 42 and is arranged on the application roller 41 as a foam-like fixer layer having a desired thickness. The foamy fixing liquid layer formed on the application roller 41 in this manner is applied onto the unfixed toner in synchronization with the passage of the nip portion of the recording medium having the unfixed toner.

  FIG. 4B is an enlarged schematic view of the application roller 41 and the film thickness adjusting blade 42. A layer of the foam-like fixing liquid is formed on the recording medium on the application roller 41 constituting the foam-like fixing liquid application unit. It is formed through a film thickness adjusting blade 42 which is a film thickness adjusting means in accordance with the thickness of the upper unfixed toner layer. With the film thickness adjusting blade 42 as the film thickness adjusting means, an unfixed toner layer of the foam-like fixing solution according to the bubble size of the foam-like fixing solution, the foam viscosity, the applied pressure and the layer thickness of the unfixed toner. The film thickness of the fixing solution layer is optimized with respect to the permeation time. As described above, the desired fine foam foam fixing solution is composed of a large foam generating section that generates large foam and a small foam generating section that separates large foam with a shearing force to generate micro foam. It is generated by the foam-like fixing liquid generating means 30 that is configured to be included, and is dropped from the liquid supply port between the coating roller 41 and the film thickness adjusting blade 42 that is the film thickness adjusting means.

  As shown in FIGS. 5A and 5B, the film thickness of the foam-like fixing solution on the application roller is adjusted using a film thickness adjusting blade 42 with a gap provided between the application roller 41 and the film thickness as shown in FIG. 5A. When the thickness is made thinner, the gap may be narrowed, and when the film thickness is made thicker as shown in FIG. 5B, the gap may be made wider. The gap is adjusted by using a drivable rotary shaft at the end of the film thickness adjusting blade 42, the thickness of the toner layer, the environmental temperature, etc., as well as the bubble size, bubble viscosity, and application pressure of the foam-like fixer. The optimum film thickness for adjusting the permeation time of the foamy fixing solution in the unfixed toner layer according to the pressure and the layer thickness of the unfixed toner may be adjusted.

  The shape, structure, size, and material of the application roller constituting the foam-like fixing liquid application unit are not particularly limited as long as the foam-type fixing liquid can be applied. It is preferable.

  The blade for adjusting film thickness may be a wire bar in addition to the blade for adjusting film thickness shown in FIGS. 5A and 5B. The thickness of the foam fixing solution on the application roller is adjusted by the wire bar. As described above, the foam fixing solution is a fine foam generating unit that generates large bubbles and a minute foam that separates the large bubbles with shearing force. It is produced | generated by the foam-like fixing liquid production | generation means which has a foam production | generation part, and is dripped between a film | membrane adjustment wire bar and a coating roller from a liquid supply port. By using the wire bar as the film thickness adjusting means, the uniformity of the foam-like fixing liquid film in the axial direction of the coating roller surface is improved as compared with the blade.

The bulk density of the foamy fixing ^{solution, 0.01g / cm 3 ~0.1g / cm} 3 in the range of about preferably. Furthermore, in order to prevent the occurrence of residual liquid feeling on the medium surface when the fixing solution applied is ^preferably from ^{0.01g / cm 3 ~0.02g / cm 3} , 0.02g / cm 3 or less is more preferable. This is because, as in the application roller 41 in FIGS. 4A and 4B, the foam film of the fixing solution on the surface of the contact imparting unit is required to be equal to or greater than the thickness of the fine particle layer on the recording medium (the gap between the fine particle layers is reduced). In general, the thickness of the foam film is preferably 50 μm to 80 μm. On the other hand, in order not to cause a residual liquid feeling (wet feeling) when the fixing liquid adheres to the surface of the recording medium, the amount of fixing liquid attached is preferably 0.1 mg / cm ² or less per unit area of the recording medium. . Therefore, as the bulk density of the ^foam, preferably in the range of ^{0.0125g / cm 3 ~0.02g / cm 3} , a density of 0.02 g / cm ³ or less of the foam is more preferable.

  FIG. 6 is a schematic configuration diagram showing the configuration of the fixing device according to the embodiment of the present invention. In the fixing device 40 of the embodiment shown in FIG. 6, the pressure roller 43 may be configured using an elastic porous body (hereinafter also referred to as a sponge material) as an elastic layer. It is necessary to set the timing of the nip time so that the coating roller and the resin fine particle layer are peeled off after the foamy fixing solution penetrates the resin fine particle layer such as toner and reaches the medium such as paper. In this respect, the pressure roller 43 made of a sponge material is preferable because it ensures a nip time in the range of 50 milliseconds to 300 milliseconds and can be greatly deformed with a weak pressure.

  The nip time is calculated by nip time = nip width / paper conveyance speed. The paper transport speed can be obtained from design data of the paper transport drive mechanism. The nip width is such that a colored paint that does not dry is applied thinly on the entire surface of the coating roller, and the recording medium is sandwiched between the coating roller 41 and the pressure roller 43 facing (pressing each roller in a non-rotating state) to color the recording medium. It can be determined by applying paint and measuring the length in the paper conveyance direction at the colored portion (usually colored in a rectangular shape) as the nip width.

  By adjusting the nip width according to the conveyance speed of the recording medium, the nip time needs to be equal to or longer than the toner layer permeation time of the foamy fixing solution. In the example shown in FIG. 6, the pressure roller 43 is made of a sponge material as an elastic layer, so that the distance between the axes of the application roller 41 and the pressure roller 43 is changed according to the conveyance speed of the recording medium, and the nip width is increased. It becomes easy to change. Elastic rubber may be used as the material for the pressure roller 43 instead of sponge, but the sponge can be deformed with a weaker force than the elastic rubber, and without applying excessive pressure to the application roller 41. A long nip width can be secured.

  Note that a liquid plasticizer is contained in the fixing liquid, and if the fixing liquid should adhere to the pressure roller formed of the sponge material, there is a possibility that problems such as softening of the sponge material may occur. Therefore, the resin material of the sponge material is preferably a material that does not soften or swell with respect to the liquid plasticizer. Further, the pressure roller using a sponge material may be configured to be covered with a flexible film. Even if the sponge material is a material that deteriorates with a liquid plasticizer, the sponge roller can be prevented from being deteriorated by covering with a flexible film that does not soften or swell with the liquid plasticizer. There is no restriction | limiting in particular as a sponge material, For example, the porous body of resin, such as polyethylene, a polypropylene, polyamide, is mentioned. Moreover, as long as it has flexibility, there is no restriction | limiting in particular as a flexible film which covers sponge, For example, a polyethylene terephthalate, polyethylene, a polypropylene, a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA) is mentioned, for example. It is done.

  In FIG. 6, when the application roller 41 and the pressure roller 43 using a sponge material are always in contact, the foamy fixing solution on the application roller 41 is transferred to the pressure roller 43 when the recording medium is not conveyed. There is a risk of adhering to and soiling. In order to prevent this, a paper leading edge detection means (not shown) is provided upstream in the recording medium conveyance direction as viewed from the application roller 41, and the foam-like fixing liquid is applied only from the leading edge of the recording medium to the rear according to the leading edge detection signal. It is preferable to form the foam-like fixing liquid on the application roller 41 at the timing of application.

  In the fixing device 40 shown in FIG. 6, the application roller 41 and the pressure roller 43 using a sponge material are separated from each other during standby, and the leading end of the recording medium is detected only during application by a drive mechanism (not shown). It is also preferable that the application roller 41 and the pressure roller 43 using a sponge material are brought into contact with each other depending on the means. The fixing device 40 shown in FIG. 6 also detects the trailing edge of the recording medium and separates the application roller 41 and the pressure roller 43 using a sponge material in accordance with the trailing edge detection signal of the recording medium. It is also preferable to do.

  FIG. 7 is a schematic configuration diagram showing another configuration of the fixing device according to the embodiment of the present invention. The fixing device 40 according to the embodiment shown in FIG. 7 uses a pressure belt 44 instead of the pressure roller 43 shown in FIG. A liquid produced by a foam-like fixing liquid producing means 30 comprising a large foam producing part that produces large foam and a fine foam producing part that separates the large foam with a shearing force to produce fine foam. A foam-like fixing solution having a desired bubble diameter is supplied from a supply port to a supply port of a film thickness adjusting blade 42 which is a film thickness adjusting means using a tube or the like. Then, the gap between the film thickness adjusting blade 42 of the film thickness adjusting means and the application roller 41 is adjusted to adjust the layer thickness of the foam-like fixing solution on the application roller 41, and the optimum film thickness of the foam-like fixing solution is adjusted. Make adjustments. As a material of the pressure belt 44, for example, a member such as a seamless nickel belt, a seamless PET file, or the like coated with a releasable fluororesin such as PFA may be used.

  Thus, in the configuration using the belt, the nip width can be easily widened. Therefore, the configuration using the belt is not limited to FIG. 7, and a configuration in which the application roller is a belt and the pressing unit is not a belt but a roller is preferable. Further, by using at least one of the application side and the pressure side as a belt, the nip width can be easily widened, and an excessive force that causes wrinkles on the paper is not applied. Further, when the nip time and the paper transport speed are the same, the paper transport speed can be increased and high-speed fixing can be performed.

  In addition, the toner fixing device may include a pair of smoothing rollers (hard rollers) that pressurize at least a part of the softened or swollen toner after supplying the fixing liquid of the present invention to the toner. By pressurizing the above softened or swollen toner with a pair of smoothing rollers (hard rollers), the surface of the softened or swollen toner layer can be smoothed to give the toner gloss. Furthermore, by fixing the softened or swollen toner into the recording medium, the fixing property of the toner to the recording medium can be improved.

<Other processes and other means>
<< Heating process and heating means >>
The fixing method and the fixing device according to the present invention may further include a heating step and a heating means for heating the resin fine particle layer provided with the foamy fixing solution. The heating temperature in the heating step and the heating means is not particularly limited as long as sufficient fixing characteristics can be obtained, but for example, 50 ° C to 100 ° C is preferable. If the heating temperature is less than 50 ° C., fixing may be insufficient, and if it exceeds 100 ° C., it is uneconomical in terms of energy consumption.

  As a form of the heating means, a roller or the like may be appropriately selected as long as the above-described aspect can be implemented. When the heating means is constituted by a roller, for example, as shown in FIG. 8, it is constituted by a pressure roller 46 and a pressure roller 48, and a heating medium such as an infrared heater 47 is applied to the roller in contact with the fixing object. It may be provided.

(Image forming method and image forming apparatus)
The image forming method according to the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, and other steps appropriately selected as necessary, for example, a static elimination step and a cleaning step. , Including recycling process, control process, etc.

  The image forming apparatus according to the present invention includes at least an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit, and further appropriately selected as necessary. It has other means, for example, static elimination means, cleaning means, recycling means, control means and the like.

  The image forming method according to the present invention can be preferably carried out by the image forming apparatus according to the present invention, the electrostatic latent image forming step can be performed by an electrostatic latent image forming unit, and the developing step can be performed by a developing unit. The transfer step can be performed by a transfer unit, the fixing step can be performed by a fixing unit, and the other steps can be performed by the other unit.

<Electrostatic latent image forming process>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier. There are no particular restrictions on the material, shape, structure, size, etc. of the electrostatic latent image carrier (hereinafter also referred to as “electrophotographic photoreceptor”, “photoreceptor”, “image carrier”), It can select suitably from a well-known thing. The shape is preferably a drum shape, and examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Among these, amorphous silicon is preferable from the viewpoint of long life.

  The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image bearing member and then exposing it imagewise, and by electrostatic latent image forming means. Can do. The electrostatic latent image forming means includes, for example, at least a charger that uniformly charges the surface of the electrostatic latent image carrier and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise.

  The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using a charger. The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, the charger includes a conductive or semiconductive roll, a brush, a film, a rubber blade, etc., which is known per se. Non-contact chargers utilizing corona discharge such as a charger, corotron, scorotron, etc. are preferred.

  The exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier imagewise using an exposure device. The exposure device is not particularly limited as long as the surface of the electrostatic latent image carrier charged by the charger can be exposed like an image to be formed, and can be appropriately selected according to the purpose. However, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system are preferable. In the present invention, a back light system in which imagewise exposure is performed from the back surface side of the electrostatic latent image carrier may be employed.

<Development process and development means>
The developing step is a step of forming a visible image by developing the electrostatic latent image formed on the electrostatic latent image carrier using a developer containing toner. The visible image can be formed, for example, by developing the electrostatic latent image using a developer containing toner, and can be performed by a developing unit.

  The developing means is not particularly limited as long as it can be developed using toner, for example, and can be appropriately selected from known ones. For example, toner is accommodated and the electrostatic latent image has toner. A developer having at least a developer capable of applying a developer in a contact or non-contact manner is preferably exemplified, and a developer having a toner-containing container is more preferable.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multicolor developing unit. For example, a toner having a stirrer for charging the toner by frictional stirring and a rotatable magnet roller is preferable.

  In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state, thereby forming a magnetic brush. Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier (photosensitive member), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrostatically latent due to an electric attractive force. It moves to the surface of the image carrier (photoreceptor). As a result, the electrostatic latent image is developed with toner, and a visible image is formed with toner on the surface of the electrostatic latent image carrier (photoconductor).

<Transfer process and transfer means>
The transfer step is a step of transferring a visible image to a recording medium, and there is no particular limitation. However, after using the intermediate transfer member to primarily transfer the visible image onto the intermediate transfer member, the visible image is transferred to the recording medium. A mode in which secondary transfer is performed on a recording medium is preferable. In addition, a primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer member using two or more colors, preferably full color toner as a toner, and transferring the composite transfer image onto a recording medium A mode including a secondary transfer step is more preferable.

  The transfer can be performed, for example, by charging an electrostatic latent image carrier (photoconductor) using a transfer charger, and can be performed by a transfer unit. The transfer unit includes a primary transfer unit that transfers a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. Is preferred.

  The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The transfer means (primary transfer means, secondary transfer means) includes at least a transfer device that peels and charges the visible image formed on the electrostatic latent image carrier (photoconductor) to the recording medium side. What has is preferable. There may be one transfer means, or two or more transfer means.

  Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

  The recording medium is not particularly limited and may be appropriately selected from known recording media (recording paper), and those described for the fixing liquid according to the present invention may be used.

<< Fixing process and fixing means >>
The fixing step is a step of fixing the transferred image transferred to the recording medium, and may be performed by the fixing method according to the present invention.

  The fixing means is means for fixing the transferred image transferred to the recording medium, and may be performed using the fixing device according to the present invention.

<Other steps and means>
<< Static elimination process and static elimination means >>
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit.

  The neutralization means is not particularly limited as long as it can apply a neutralization bias to the electrostatic latent image carrier, and can be appropriately selected from known neutralizers. For example, a neutralization lamp or the like is preferable. It is done.

<< Cleaning process and cleaning means >>
The cleaning step is a step of removing toner remaining on the electrostatic latent image carrier, and can be suitably performed by a cleaning unit.

  The cleaning means is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, static Preferred examples include an electric brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

<< Recycling process and recycling means >>
The recycling process is a process in which the toner removed by the cleaning process is recycled to the developing unit, and can be suitably performed by the recycling unit.

  There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

<< Control process and control means >>
The control step is a step of controlling each step of the image forming method according to the present invention, and can be suitably performed by a control unit.

  The control unit is not particularly limited as long as it can control the movement of each unit of the image forming apparatus according to the present invention, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers. It is done.

  An image of a toner composed of resin fine particles may be formed on a recording medium using the image forming method according to the present invention. Therefore, according to the image forming apparatus of the embodiment of the present invention, as described above, an image forming method and an image forming apparatus capable of fixing toner onto a recording medium more efficiently are provided. can do.

  9A and 9B are schematic views showing the configuration of the image forming apparatus according to the present invention. FIG. 9A is a schematic view of the entire color electrophotographic tandem type image forming apparatus, and FIG. It is a figure which shows the structure of one image forming unit of the image forming apparatus of FIG. 9A. The image forming apparatus 50 shown in FIGS. 9A and 9B may be a copying machine or a printer.

  The image forming apparatus 50 shown in FIGS. 9A and 9B includes an intermediate transfer belt 51 as a toner image carrier. The intermediate transfer belt 51 is stretched around three support rollers 52 to 54 and rotates in the direction of arrow A in the figure. On the intermediate transfer belt 51, black, yellow, magenta and cyan image forming units 55 to 58 are arranged. Above these image forming units, an exposure device (not shown) is arranged. For example, when the image forming apparatus is a copying machine, each exposure L1 to L4 for reading image information of an original with a scanner and writing an electrostatic latent image on each photosensitive drum according to the image information is performed. Irradiated by an exposure apparatus. A secondary transfer device 59 is provided at a position facing the support roller 54 of the intermediate transfer belt 51 with the intermediate transfer belt 51 interposed therebetween. The secondary transfer device 59 includes a secondary transfer belt 62 stretched between two support rollers 60 and 61. As the secondary transfer device 59, a transfer roller may be used in addition to the transfer belt. A belt cleaning device 63 is disposed at a position facing the support roller 52 of the intermediate transfer belt 51 with the intermediate transfer belt 51 interposed therebetween. The belt cleaning device 63 is arranged to remove toner remaining on the intermediate transfer belt 51.

  A recording sheet 64 as a recording medium is guided to a secondary transfer unit by a pair of paper feed rollers 65, and the secondary transfer belt 62 is pressed against the intermediate transfer belt 51 when the toner image is transferred to the recording sheet 64. Thus, the toner image is transferred. The recording paper 64 to which the toner image has been transferred is conveyed by the secondary transfer belt 62, and the unfixed toner image transferred to the recording paper 64 is foamed based on image information from an exposure device (not shown). Fixing is performed by the fixing device according to the present invention, which adjusts the film thickness of the fixing solution. That is, for the unfixed toner image transferred to the recording paper 64, the film thickness of the foam-like fixing liquid layer is adjusted based on image information from an exposure device (not shown), for example, a color image or a black solid image. A part (solid plasticizer and / or a solid plasticizer and / or a part which softens or swells at least a part of resin fine particles contained in the toner, which is supplied with the foam fixing solution of the present invention supplied from the toner fixing device and is contained in the foam fixing solution. Alternatively, an unfixed toner image is fixed on the recording paper 64 by a liquid plasticizer.

  Next, the image forming unit will be described. As shown in FIG. 9B, in the image forming units 55 to 58, a charging device 67, a developing device 68, a cleaning device 69, and a charge removal device 70 are disposed around the photosensitive drum 66. Further, a primary transfer device 71 is provided at a position facing the photosensitive drum 66 with the intermediate transfer belt 51 interposed therebetween. Further, the charging device 67 may be a contact charging type charging device employing a charging roller. The charging device 67 uniformly charges the surface of the photosensitive drum 66 by bringing a charging roller into contact with the photosensitive drum 66 and applying a voltage to the photosensitive drum 66. As the charging device 67, a non-contact charging type charging device that employs a non-contact scorotron or the like may be employed. Further, the developing device 68 causes the toner in the developer to adhere to the electrostatic latent image on the photosensitive drum 66 to visualize the electrostatic latent image.

  Here, the toner corresponding to each color is composed of resin fine particles colored in the respective colors, and these resin fine particles are swollen or softened by the fixing liquid according to the present invention. The developing device 68 has a stirring unit and a developing unit (not shown), and the developer not used for development is returned to the stirring unit and reused. The toner concentration in the agitation unit is detected by a toner concentration sensor, and is controlled so that the toner concentration is constant. Further, the primary transfer device 71 transfers the toner visualized on the photosensitive drum 66 to the intermediate transfer belt 51. Here, a transfer roller is employed as the primary transfer device 71, and the transfer roller is pressed against the photosensitive drum 66 with the intermediate transfer belt 51 interposed therebetween. As the primary transfer device 71, a conductive brush, a non-contact corona charger, or the like can be employed. The cleaning device 69 removes unnecessary toner on the photosensitive drum 66. As the cleaning device 69, a blade having a tip pressed against the photosensitive drum 66 can be used. Here, the toner recovered by the cleaning device 69 is recovered by the developing device 68 and reused by a recovery screw and a toner recycling device (not shown). Further, the static eliminator 70 is constituted by a lamp, and initializes the surface potential of the photosensitive drum 66 by irradiating light.

  Since the image forming method and the image forming apparatus according to the present invention use the fixing solution, the fixing method, and the fixing apparatus according to the present invention, the fixing property is good, and a high-quality image can be obtained without curling a recording medium such as paper. Can be formed.

  EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example.

-Foaming agent: Preparation of fatty acid amine salt-
Fatty acid in which the mass ratio of myristic acid (manufactured by Kanto Chemical Co., Inc.), palmitic acid (manufactured by Kanto Chemical Co., Ltd.), stearic acid (manufactured by Kanto Chemical Co., Ltd.) was 4: 3: 1, and diethanolamine ( Kanto Chemical Co., Ltd.) was measured so that the molar ratio was 1: 0.7, stirred in ion exchange water at a liquid temperature of 80 ° C. for 30 minutes, and allowed to cool to room temperature. Fatty acid diethanolamine salt was prepared.

Example 1
Composition comprising 30% by mass of diethoxyethoxyethyl succinate (High Aquastar DCS, manufactured by Higher Alcohol Industry Co., Ltd.) as a softening agent, 4% by mass of the fatty acid diethanolamine salt as a foaming agent, and 66% by mass of ion-exchanged water as a diluent. The solution was stirred for 10 minutes with an ultrasonic homogenizer to produce the fixer in Example 1.

(Example 2)
In Example 1, the blending amount of diethoxyethoxyethyl succinate as a softening agent was changed from 30% by mass to 15% by mass, and alcohol alkoxylate (BYK-DYNWET 800, manufactured by Big Chemie Japan Co., Ltd.) 3 as a wettability improver. A fixing solution in Example 2 was produced in the same manner as in Example 1 except that the blending amount was changed from 66% by weight to 78% by weight.

(Example 3)
In Example 2, 10% by mass of polyethylene glycol (polyethylene glycol 6000, manufactured by Kanto Chemical Co., Inc.) having a molecular weight of about 6,000 is blended as a viscosity modifier, and the blending amount of ion-exchanged water is 78% to 68% as a diluent. The fixing solution in Example 3 was produced in the same manner as in Example 2 except that the percentage was changed to%.

Example 4
In Example 2, the fixing solution in Example 4 was produced in the same manner as in Example 2 except that propylene carbonate (manufactured by Kanto Chemical Co., Inc.) was used in place of diethoxyethoxyethyl succinate as the softening agent. did.

(Example 5)
In Example 4, 10% by mass of polyethylene glycol (polyethylene glycol 6000, manufactured by Kanto Chemical Co., Inc.) having a molecular weight of about 6,000 is blended as a viscosity modifier, and the blending amount of ion-exchanged water is 78 to 68% as a diluent. A fixing solution in Example 5 was produced in the same manner as in Example 4 except that the amount was changed to mass%.

(Example 6)
In Example 1, the fixing in Example 6 was performed in the same manner as in Example 1 except that triethylene glycol diacetate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of diethoxyethoxyethyl succinate as the softening agent. A liquid was produced.

(Example 7)
In Example 6, the blending amount of triethylene glycol diacetate as a softening agent was changed from 30% by mass to 15% by mass, and an alcohol alkoxylate (BYK-DYNWET 800, manufactured by Big Chemie Japan Co., Ltd.) 3 as a wettability improver. A fixing solution in Example 7 was produced in the same manner as in Example 6 except that the blending amount was changed from 66% to 78% by weight.

(Example 8)
In Example 7, 10% by mass of polyethylene glycol (polyethylene glycol 6000, manufactured by Kanto Chemical Co., Inc.) having a molecular weight of about 6,000 was blended as a viscosity modifier, and the blending amount of ion-exchanged water was 78% to 68% as a diluent. The fixing solution in Example 8 was produced in the same manner as in Example 7 except that the percentage was changed to%.

Example 9
In Example 2, the blending amount of the fatty acid diethanolamine salt as a foaming agent was changed from 4% by weight to 2% by weight, and the blending amount of the alcohol alkoxylate as a wettability improving agent was changed from 3% by weight to 1% by weight. The same as Example 2 except that 15% by mass of tripropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) was blended as a solubilizing agent, and the blending amount of ion-exchanged water was changed from 78% to 67% by mass as a diluent. Thus, the fixing solution in Example 9 was produced.

(Example 10)
In Example 2, as a foaming agent, Example 2 was used except that instead of the fatty acid diethanolamine salt, coconut oil fatty acid acylglutamic acid triethanolamine salt (Amino Surfact ACMT-L, manufactured by Asahi Kasei Chemicals) was used. Similarly, the fixing solution in Example 10 was produced.

(Example 11)
In Example 2, polyoxyethylene lauryl ether sodium acetate (NIKKOL AKYPO RLM 45 NV, manufactured by Nikko Chemicals) was used as the foaming agent in place of the fatty acid diethanolamine salt, in the same manner as in Example 2. Then, the fixing solution in Example 11 was produced.

(Comparative Example 1)
In Example 2, alcohol alcoholate was not blended as a wettability improving agent, and the blending amount of ion-exchanged water as a diluent was changed from 78% by mass to 81% by mass in the same manner as in Example 2, A fixing solution in Comparative Example 1 was produced.

(Comparative Example 2)
In Example 2, a comparative example was made in the same manner as in Example 2 except that diethoxyethoxyethyl succinate was not blended and the blending amount of ion-exchanged water as a diluent was changed from 78% by mass to 93% by mass. The fixer in No. 2 was produced.

(Comparative Example 3)
In Example 2, a comparative example was made in the same manner as in Example 2 except that polyether-modified siloxane (BYK-349, manufactured by Big Chemie Japan Co., Ltd.) was used in place of the alcohol alkoxylate as the wettability improver. 3 was produced.

(Comparative Example 4)
In Example 2, a comparative example was used in the same manner as in Example 2 except that polyoxyethylene alkyl ether (NIKKOL BT-12, manufactured by Nikko Chemicals Co., Ltd.) was used in place of the alcohol alkoxylate as the wettability improver. 4 was produced.

(Measurement method and evaluation method of wettability)
The contact angle is a dynamic contact angle (change in contact angle with time) by a so-called droplet method, and can be measured with a commercially available dynamic contact angle meter. This dynamic contact angle is one measure representing the wettability of a liquid with respect to a solid. Generally, the better the wettability, the smaller the contact angle. That is, it can be said that the greater the change in the contact angle, the better the wettability.
Here, when the contact angle of the fixing solution with respect to the resin layer formed of resin fine particles becomes 40 degrees or less within 0.3 seconds from the time when the fixing solution contacts the resin layer, the good wettability To do. When having such wettability, the fixing solution easily penetrates between the resin particles of the resin layer, and the nip time can be reduced even when the coating amount is 100 mg or less during high-speed printing with a paper conveyance speed of 300 mm / sec. > Penetration time relationship can be obtained and stable fixing can be achieved.
Hereinafter, a method for measuring a contact angle when toner is used as the resin-containing fine particles using the fixing solutions in Examples 1 to 11 and Comparative Examples 1 to 4 will be described.

Using an electrophotographic printer Imagio mpc 3300 (manufactured by Ricoh), unfixed toner (manufactured by Ricoh, imagio mp spot toner) was deposited on the paper surface to form a toner layer with a thickness of 30 μm. This was heated for 6 minutes in a constant temperature bath at a temperature of 74 ° C., and the toner particles were slightly adhered to such an extent that the gaps between the toner particles were not filled.
From above, using a syringe with a needle (needle outer diameter: 0.36 mm), a fine droplet of the fixing liquid (droplet diameter: 0.7 mm) is dropped onto the toner layer, and the fixing is performed. A state after 0.3 seconds from the time when the liquid contacted the toner layer was photographed at 30 fps from the lateral direction of the toner layer by a video camera, and the contact angle was measured from the imaged data. This measurement was performed in an environment of a temperature of 20 ° C. and a humidity of 50%. The results are shown in Table 1 below.
At the same time, the contact change over time from the time when the fixing solution contacts the toner layer is shown in FIG.
Here, the contact angle is an angle indicated by θ in FIG. 11, in which 100 indicates a toner layer and 101 indicates a fixing liquid.

  Since there are many gaps in the unfixed toner layer, the fixing solution is absorbed (penetrated) into the layer with time, and the contact angle changes accordingly. If the thickness of the toner layer is less than 30 μm, the fixer may come into direct contact with the underlying paper during landing, and an accurate contact angle may not be measured due to liquid absorption by the underlying paper. Further, when the particle diameter of the toner is 5 μm to 10 μm, the size of the dropped liquid droplet is 0.5 mm to 1.0 mm in diameter. If the droplet is less than 0.5 mm in diameter, the influence of the toner shape on the contact angle cannot be ignored, and the accurate contact angle may not be measured. If the droplet is larger than 1.0 mm, the droplet may collapse due to its own weight, and an accurate contact angle may not be measured.

In addition to the measurement of the contact angle, the surface tension and viscosity were measured as follows for the fixing solutions in Examples 1 to 11 and Comparative Examples 1 to 4.
That is, the surface tension was measured using a dynamic surface tension meter Theta t60 / 2 manufactured by Eiko Seiki Co., Ltd., when the bubble generation period was 0.05 Hz. The viscosity was measured at a shear rate of 20 rpm using a viscous clock TVE-22L manufactured by Toki Sangyo. All were measured in an environment of temperature 25 ° C. and humidity 50%.
In general, the lower the surface tension and viscosity of the liquid, the better the wettability. However, as a result of evaluating the wettability of the fixing liquid to the toner layer by the contact angle measurement method, the wettability is not necessarily the surface tension. And it was confirmed that it was not dependent only on the viscosity. The results are shown in Table 2 below.

(Measurement method and evaluation method of offset)
An unfixed toner image (color image) was formed on A4-size PPC paper using an electrophotographic printer Imagio mpc 3300 (manufactured by Ricoh).
Next, an unfixed toner image was fixed using the fixing device 50 of FIG. 4A. First, the fixing solution is foamed using the foaming device 30 of FIG. The container 31 is a bottle made of PET resin, and is a pump 33, a tube pump having a tube made of silicone rubber and an inner diameter of 2 mm, and a flow path for conveying the fixing liquid L is a silicone rubber tube having an inner diameter of 2 mm. is there. Further, the microporous sheet 37 of the coarse bubble generating part 35 is a stainless steel 400 mesh sheet having an opening of about 40 μm. Furthermore, the inner cylinder and the outer cylinder in the bubble generating unit 38 are made of PET, the inner cylinder has an outer diameter of 8 mm and a length of 100 mm, and the outer cylinder has an inner diameter of 10 mm and a length of 100 mm. 120 mm. At this time, the inner cylinder of the foam generating unit 38 was fixed to the rotating shaft, and was rotated by a rotation drive motor (not shown) to create a foam-like fixer.
At this time, the rotation speed was set so that the bubble density was 0.04 g / cm ³ . The obtained foam was supplied to the application roller 41.
The application roller 41 is a 50 mm diameter SUS roller baked and coated with PFA resin, and the pressure roller 43 is a 22 mm diameter SUS roller (core metal) with an outer diameter of 40 mm. In addition, a silicon sponge formed was used.
The pressing force of the pressure roller 43 was set so that the nip width was 7 mm and the surface pressure was 0.27 kgf / cm ² .
Further, as the blade 42, a flat glass having a thickness of 1 mm is adhered to a support plate made of an aluminum alloy, the glass surface is directed toward the application roller 43, and the thickness of the foamed fixing solution on the application roller 43 is determined. Was set to about 50 μm so that the gap with the coating roller 43 was set.
As a result, the application amount of the fixing solution is about 100 mg per A4 sheet. The conveyance speed of the recording paper P was set to 300 mm / second.
At this time, the thickness of the unfixed toner image was set to 30 μm to 40 μm. In addition, the toner used was an image mp spot toner manufactured by Ricoh Co., and the fixing solutions in Examples 1 to 11 and Comparative Examples 1 to 4 were used as the fixing solutions.

-Evaluation of fixed images-
Regarding the image quality of the image output by the image forming method, the degree of toner offset was evaluated according to the following criteria. The results are shown in Table 1 below.
A: A good image was obtained without toner offset.
X: Toner offset occurs and the image is greatly disturbed.

* However, in Table 1 above, the contact angle is a value 0.3 seconds after the fixing solution contacts the toner layer.

As understood from the results in Table 1, the fixing solutions in Examples 1 to 11 and Comparative Examples 1 to 4 that have a contact angle of 40 degrees or less within 0.3 seconds after the fixing solution contacts the toner layer. By using this, a good image can be obtained.
Therefore, according to the present invention, since the fixer has excellent permeability to the resin fine particles, it is possible to prevent the offset while keeping the amount of the fixer applied to a small amount even during high-speed printing.
Further, as shown in Table 2, it was confirmed that the contact angle of the fixing solution did not depend on the surface tension and the viscosity.

  The fixing solution of the present invention can be suitably used as a fixing solution that can be used in an electrophotographic forming technique employing a non-thermal fixing method.

DESCRIPTION OF SYMBOLS 11 Application roller 12 Recording medium 13 Resin fine particle layer 14 Foam fixing liquid 20 Foam fixing liquid 21 Liquid film boundary 22 Bubble 30 Foam fixing liquid generating means 31 Fixing liquid container 32 Liquid fixing liquid 33 Conveying pump 34 Liquid conveying pipe 35 Gas Liquid mixing section 36 Air port 37 Micropore sheet 38 Foam generating section 40 Fixing device 41 Coating roller 42 Film thickness adjusting blade 43 Pressure roller 44 Pressure belt 45 Heating means 46 Pressure roller 47 Infrared heater 48 Pressure roller DESCRIPTION OF SYMBOLS 50 Image forming apparatus 51 Intermediate transfer belt 52 Support roller 53 Support roller 54 Support roller 55 Image forming unit 56 Image forming unit 57 Image forming unit 58 Image forming unit 59 Secondary transfer device 60 Support roller 61 Support roller 62 Secondary transfer belt 63 Belt cleaning device 64 Recording paper 65 Feeding roller 66 Photosensitive drum 67 Charging device 68 Developing device 69 Cleaning device 70 Neutralizing device 71 Primary transfer device 81 Application roller 82 Recording medium 83 Unfixed toner layer 84 Fixing liquid layer 100 Toner layer 101 Fixing liquid

JP 2007-219105 A JP 2009-008967 A

Claims (12)

A fixing solution for fixing resin fine particles to a recording medium,
A diluent containing water, a foaming agent that foams the fixing solution, a plasticizer that dissolves or swells at least a part of the resin fine particles, and wettability that improves wettability to the resin fine particles And a fixing agent. A fixing solution for fixing resin fine particles to a recording medium,
The contact angle of the fixing solution with respect to the unfixed resin layer formed of the resin fine particles is 40 degrees or less within 0.3 seconds from the time when the fixing solution contacts the resin layer. Fixer.   The fixing solution according to claim 1, wherein the wettability improving agent has a functional group having an affinity for the resin fine particles.   The fixing solution according to claim 1, wherein the wettability improving agent is a compound having an ester group in the molecule.   The fixing solution according to claim 1, wherein the wettability improving agent is an alcohol alkoxylate.   The fixing solution according to claim 1, further comprising a viscosity modifier that adjusts the viscosity of the fixing solution.   The fixing solution according to claim 1, further comprising a solubilizer that promotes softening of the resin fine particles.   The fixing liquid according to claim 1, wherein the resin fine particles are toner. A foam-like fixing solution generating step for producing a foam-like fixing solution by foaming the fixing solution according to claim 1;
A film thickness adjusting step for forming the foamy fixer to a desired thickness on the contact surface of the foamy fixer applying means,
A foam-like fixing solution applying step of applying the foam-like fixing solution formed in the desired thickness to the resin fine particle layer on the recording medium;
A fixing method comprising the steps of: A foam-like fixing solution generating means for forming a foam-like fixing solution by foaming the fixing solution according to claim 1;
A foam-like fixing solution applying means for applying the foam-like fixing solution to the resin fine particle layer on the recording medium;
Film thickness adjusting means for adjusting the film thickness of the foam-like fixing solution of the foam-like fixing solution applying means,
A fixing device. An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier;
A developing step of developing the electrostatic latent image using a developer containing toner having resin fine particles to form a visible image;
A transfer step of transferring the visible image to a recording medium;
A fixing step of fixing the transferred image transferred to the recording medium;
An image forming method comprising:
An image forming method, wherein the fixing step is performed by the fixing method according to claim 9. An electrostatic latent image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier;
Developing means for developing the electrostatic latent image using a developer containing toner having resin fine particles to form a visible image;
Transfer means for transferring the visible image to a recording medium;
Fixing means for fixing the transferred image transferred to the recording medium;
An image forming apparatus having
The image forming apparatus according to claim 10, wherein the fixing unit is the fixing device according to claim 10.