Patent Grant
7773932
1. Field of the Invention
The present invention relates to a fixation device, a fixation method, an image forming apparatus, an image forming method and a fixation fluid.
2. Description of the Related Art
An image forming apparatus such as a printer, a facsimile machine and a copying machine is an apparatus for forming an image containing a character or a symbol on a recording medium such as paper, cloth and OHP sheets, based on image information. Particularly, an electrophotographic image forming apparatus has widely been used in offices since a highly fine image may be formed on a normal paper sheet at a high speed. In such an electrophotograhpic image forming apparatus, a thermal fixation process has widely been used in which toner is fixed on a recording medium by heating and fusing the toner on the recording medium and applying a pressure on the fused toner. The thermal fixation process has preferably been used since a high fixation speed and a high fixed-image quality may be provided.
However, a half or more of electric power consumed in such an electrophotographic image forming apparatus is used for heating toner in the thermal fixation process. On the other hand, a fixation device with low electric power consumption (energy saving) is desired from the viewpoint of dealing with environmental problems in recent years. That is, it is desired to extremely lower the temperature of heating of toner to fix the toner more than ever before, or to provide a fixation method which does not require toner heating. Particularly, a non-heating fixation method for fixing toner on a recording medium while no toner is heated at all is ideal in view of the low electric power consumption.
For such a non-heating fixation method, for example, Japanese Patent No. 3,290,513 suggests a wet-type toner fixation method which includes spraying or dropping an oil-in-water-type fixing agent in which an organic compound being capable of dissolving or swelling toner and insoluble or difficult to dissolve in water is dispersed and mixed in water, onto unfixed toner provided at a predetermined position on a surface of a substrate so as to dissolve or swell the toner, and subsequently drying the substrate.
However, since the oil-in-water-type fixing agent in which an organic compound being insoluble or difficult to dissolve in water is dispersed and mixed in water is used in the wet-type fixation method disclosed in Japanese Patent No. 3,290,513, a recording medium (substrate) such as a transcription paper sheet may absorb the water and thereby cockling or curling may occur on the recording medium when a large amount of the fixing agent is provided to unfixed toner. Accordingly, stable and high speed conveyance of a recording medium which is required for an image forming apparatus may be significantly disturbed. Herein, if the water is removed from the fixing agent provided on the recording medium by evaporating a large amount of water contained in the fixing agent using a dryer, a electric power would be required which is comparable with the electric power consumption of an image forming apparatus using a thermal fixation process.
Furthermore, for a fixation liquid which does not repel water-repellent treated and unfixed toner, some oily fixation liquids have conventionally been suggested in which a material for dissolving or swelling toner is dissolved in an oily solvent. For one example of them, for example, Japanese Patent Application Publication No. 2004-109749 suggests a fixation liquid in which, for example, an aliphatic dibasic acid ester as a material component for dissolving or swelling a resin component constituting toner is diluted (dissolved) in non-volatile dimethylsilicone as a diluent (solvent). Also, Japanese Patent Application Publication No. 59-119364 suggests a solution for fixing an unfixed toner image which may be used for a fixation method capable of fixing an unfixed image formed by an electrostatic method on an image-receiving sheet sharply and easily without causing an image irregularity, wherein 100 parts by volume of a solvent dissolving toner and having a compatibility with a silicone oil is compatibly mixed with 8-120 parts by volume of a silicone oil. Such oily fixation liquids may dissolve or swell toner without repel water-repellent treated and unfixed toner and fix the toner on a recording medium since an oily solvent having high affinity with the water-repellent treated and unfixed toner is contained.
Each of Japanese Patent Application Publication Nos. 2004-109749 and 59-119364 discloses a configuration for providing a liquid onto unfixed toner. However, as shown in
On the other hand, as shown in
As described above, it may be very difficult to attain both application of a small amount of a fixation liquid onto a toner layer on a paper sheet for improving fixation responsibility and uniform application without causing an irregularity of a toner image, by the contact application part and the conventional formulation of a fixation liquid.
According to one aspect of the present invention, there is provided a fixation device configured to fix on a medium a resin fine particle that contains a resin, by providing a fixation fluid on the resin fine particle on the medium which fixation fluid contains a softening agent that softens the resin fine particle by dissolving or swelling at least one portion of the resin, water and a foaming agent that comprises a salt of aliphatic acid, wherein the fixation device comprises a foam-like fixation fluid producing part configured to produce a foam-like fixation fluid, a layer thickness controlling part configured to control a layer thickness of the produced foam-like fixation fluid, and a provision part configured to provide the layer-thickness-controlled foam-like fixation fluid on the resin fine particle on the medium.
According to another aspect of the present invention, there is provided an image forming apparatus which comprises an image forming part configured to form an unfixed toner image on a medium by conducting an electrostatic recording process with a toner in which a resin fine particle contains a coloring agent, and a fixation part configured to fix the unfixed toner image on the medium, with the fixation device as described above.
According to another aspect of the present invention, there is provided a fixation fluid configured to fix a resin fine particle on a medium by producing the fixation fluid in a foam-like condition and providing the produced foam-like fixation fluid on the resin fine particle on the medium, the fixation fluid contains a softening agent that softens the resin fine particle by dissolving or swelling at least one portion of the resin fine particle, water and a foaming agent that comprises a salt of aliphatic acid.
The preferred embodiments of the present invention are described below, with reference to the accompanying drawings.
However, as shown in
Herein, when a fixation fluid contains a salt of aliphatic acid as a foaming agent and water according to an embodiment of the present invention, which salt of aliphatic acid is known as a surfactant, a fixation fluid is provided which withstands bubble breaking well so that no bubble breaking or liquefaction is caused at a contact area between the application roller 11 and the recording medium 2 such as a paper sheet.
Furthermore,
Meanwhile, the applicant disclosed a technique for applying a foam-like fixation fluid onto an intermediate transcriptional belt in Japanese Patent Application Publication No. 2004-109747 by focusing attention on the fact that a bulk density is decreased by such foaming, and suggested application of a slight amount of the foam-like fixation fluid. However, the technique disclosed in Japanese Patent Application Publication No. 2004-109747 does not aim to prevent offset or image deletion but mainly aims to reduce the amount of a fixation fluid. Also, Japanese Patent Application Publication No. 2004-109747 does not disclose a configuration of direct application fixation with a contact application part, such as roller application to unfixed toner on a recording medium such as a paper sheet, or layer thickness control but merely discloses a configuration for providing a traveling foam-like fixation liquid onto unfixed toner on an intermediate transcriptional body. Also, in contact application such as roller application, a foam-like fixation fluid containing fine air bubbles may be uniformly provided onto an unfixed toner image so as to provide a thin layer and application irregularity is not easy to occur. Furthermore, roller application was examined with a foam-like fixation fluid obtained by containing air bubbles in a fixation liquid, and it has been found that only simple application of a foam-like fixation fluid does not necessarily have an effect of preventing offset of resin fine particles onto a roller surface in roller application. Then, it has been found that control of the layer thickness of a fixation fluid layer including an air bubble layer and the configuration of the air bubble layer in a foam-like fixation fluid on the surface of an application roller in a roller application part are important for prevention of the offset.
Also, as described above, when a salt of aliphatic acid is used as a foaming agent, the foaming stability becomes higher and a foam-like fixation fluid becomes not easy to permeate into a recording medium such as a paper sheet. This is advantageous but a foam-like fixation fluid might also become not easy to permeate into a toner layer. When a fixation fluid does not permeate into a toner layer, sticking among toners due to the fixation liquid does not occur and defective fixation may be caused. Herein, it has been found that the thickness of a foam-like fixation fluid layer on an application roller and a pressure at a contact area between the application roller and a recording medium such as a paper sheet influence the permeability of the foam-like fixation fluid into a toner layer and further influence toner offset onto the application roller.
Therefore, for example, when the resin fine particles are toner particles and the medium is a recording medium such as a paper sheet and where a pressure applied on a contact area between the application roller and the recording medium is set to be low in order to preferentially reduce load on a driving system for recording medium conveyance, the average size of created air bubbles are preliminarily measured and the layer of air bubbles are controlled to be composed of plural layers, wherein the layer thickness of a foam-like fixation fluid layer on the application roller is the total thickness of plural air bubble layers, in order that unfixed toner does not offset onto the application roller. Thus, the foam-like fixation fluid layer is formed on the application roller which layer is necessarily composed of plural air bubble layers, so that it becomes possible to prevent the offset of toner.
On the other hand, where a pressure applied on a contact area between the application roller 11 and the recording medium is set to be high in order to provide a fixation fluid onto a not-necessarily smooth recording medium such as a woodfree paper sheet uniformly or without non-uniformity, a foam-like fixation fluid 14 on the application surface of an application roller 11 has a single layer structure of air bubbles 15 as shown in
Thus, when a pressure applied on a contact area between an application roller and a recording medium, the average size of air bubbles is preliminarily measured and the thickness of a fixation fluid layer is controlled to provide a foam-like fixation fluid having an air bubble layer structure with a thin layer thickness on the application roller surface which layer is a single layer as nearly as possible. Accordingly, a fluid layer having an air bubble layer structure which is nearly a single layer is formed on the application roller and toner offset may be prevented on the condition of high pressure. Also, if the air bubble layer on the application roller is too thick, flow of the air bubble layer may occur at a contact area between the application roller and the recording medium and the resin fine particles move along with the flow, whereby a disadvantage of image deletion may be caused if the resin fine particles are toner. However, it may be solved by controlling the layer thickness of a foam-like fixation fluid layer in a range causing no flow.
Although it has been described above that the contact pressure between an application roller and a medium and the layer thickness of a foam-like fixation fluid on the application roller are main factors for toner offset onto the application roller or an image irregularity, the medium may be a board postcard paperboard or thin woody paper sheet or the thickness of a paper sheet varies depending on the kind of paper sheet, whereby the contact pressure between the application roller and the medium varies. Specifically, the contact pressure for a paperboard is higher and the contact pressure for a thin paper sheet is lower. Accordingly, it may be necessary to control the layer thickness of a foam-like fixation fluid on the application roller to be in an optimum range thereof depending on the kinds of those paper sheets. In addition, the thickness of a toner layer on the paper sheet varies depending on the kind of image such as monochrome, color, text, and photographic images. Specifically, when the toner layer is thicker, the contact pressure is higher and when the toner layer is thinner, the contact pressure is lower. Accordingly, it may be necessary to control the layer thickness of a foam-like fixation fluid on the application roller in an optimum range thereof depending on the thickness of the toner layer based on image information. In any event, good fixation is not necessarily conducted by simply using a foam-like fixation fluid, and it is substantially necessary to control the layer thickness of a foam-like fixation fluid by means of application depending on a contact pressure which is adjusted based on an application condition such as the kind of paper sheet and the thickness of a toner layer.
As described above, toner offset onto a contact application part such as an application roller or image deletion may be prevented by controlling the layer thickness oh a layer of foam-like fixation fluid which contains a softening agent, water and a salt of aliphatic acid as a foaming agent, whereby fixation with a slight amount application may be attained. That is, an embodiment of the present invention is a method for fixing resin fine particles on a medium by applying a fixation fluid onto the resin fine particles on the medium using a contact application part and a fixing agent obtained by containing into a fixation fluid a softening agent that dissolves or swells at least one portion of the resin fine particle so as to soften the resin fine particle and further containing water and a salt of aliphatic acid as a foaming agent into it. Herein, when the fixation fluid is provided on the surface of the resin fine particle on the medium, the fixation fluid is in a foam-like condition containing air bubbles in the application of the fixation fluid contacting the fine particles and further the layer thickness of the foam-like fixation fluid layer is controlled depending on a pressure applied thereto. Thereby, offset of the resin fine particles onto the contact application part such as an application roller or deletion of a resin film fine particle layer may be prevented so as to attain fixation with a slight amount application. Also, as resin fine particles, toner fine particles used for an electrophotographic technique are highly effective for an embodiment of the present invention, and toner offset or image deletion may be prevented by controlling the layer thickness of a foam-like fixation fluid layer depending on the thickness of a layer of the resin fine particles.
Next, a fixation fluid applying part in an embodiment of the present invention is described below. The fixation fluid applying part in an embodiment of the present invention is a contact application part.
Additionally, although the content of air bubbles in a foam-like fixation fluid varies depending on the bulk density and applied layer thickness thereof, it is commonly desirable the bulk density is in a range of about 0.01 g/cm3-about 0.1 g/cm3. Also, a foam-like fixation fluid including an air bubble layer means a foam-like fixation fluid including a single or plural air bubble layers, in which a distinct layer face is not necessarily required. Furthermore, it is only necessary for a fixation fluid to be foam-like at the time of application onto a layer of resin fine particles such as toner particles on a recording medium such as a paper sheet and it is not necessary to be foam-like in a stock container. It is desirable to provide a device for making a liquid containing no air bubble in a stock container be foam-like at the time of supplying the liquid from the container or in a route for conveying the liquid before it is applied onto a layer of resin fine particles. This is because the configuration of liquid in a stock container and foam-like after taking the liquid from the container has a great advantage such that the contained may be miniaturized.
Herein, a method for providing a foam-like fixation fluid is described below which contains air bubbles after taking a liquid-type fixation fluid from a closed container.
The first method is a method such that a liquid-type fixation fluid containing a softening agent in a closed container is taken from the container and subsequently a large amount of air bubbles are contained by an air bubble producing device which applies a shearing force to the liquid-type fixation fluid so as to produce air bubbles. The air bubbles are produced due to the cavitation in the fluid or involvement of air when the shearing force is applied.
Additionally, the surface of the agitation roller 43 in
The second method, as shown in
The third method, as shown in
Also, the fourth method, as shown in
Next, a method or part for controlling the thickness of a foam-like fixation fluid at the surface of a contact member is described below. The optimum layer thickness which should be controlled is determined by the average particle diameter of air bubbles formed by a foam-like fixation fluid producing part, an applied pressure at a contact area between an application part and a medium, and the fluid viscosity. As a method for controlling the fluid layer to within a determined suitable range, a method for scraping a foam-like fixation fluid while a gap with the application part is provided is suitable among application devices using a roller-shaped rotary member. For example, scraping by the fluid layer thickness controlling blade 47 described above with reference to
Next, the fluid formulation of a fixation fluid is described below. As described above, the foam-like fixation fluid has a configuration such that air bubbles are contained in a liquid containing a softening agent. The liquid containing a softening agent contains air bubbles stably and it is desirable to have a foaming agent and a bubble increasing agent in order to provide a foam-like one having air bubble layer which includes air bubbles having as a uniform size as possible. Also, when the viscosity is high to some extent, air bubbles are stably dispersed in liquid, and therefore, it is desirable to contain a thickening agent.
Also, as a foaming agent, salts of aliphatic acids are desirable. Since the salts of aliphatic acids provide surface activity, the surface tension of a fixation fluid containing water is reduced so that the fixation fluid is easily foamed. Also, since the salt of aliphatic acid has a layered or lamellar structure on the surface of a bubble, a foam wall (plateau border) thereof is more robust than those of other surfactants and foaming stability is extremely high. Furthermore, it is desirable to contain water in the fixation fluid in order to make the foamability of a salt of aliphatic acid be effective. As an aliphatic acid, saturated aliphatic acids are desirable which is resistant to oxidation, from the viewpoint of long-term stability in atmosphere. However, when a slight amount of a salt of unsaturated aliphatic acid is contained in a fixation fluid containing a salt of saturated aliphatic acid, the solubility or dispersibility of the salt of aliphatic acid is improved to have excellent foamability at a low temperature of 5° C. through 15° C., whereby stable fixation may be attained in a wide range of environmental temperature and the separation of a salt of aliphatic acid in a fixation fluid may be prevented when the fixation fluid is left within a long time period.
Moreover, as an aliphatic acid used for a salt of saturated aliphatic acid, saturated aliphatic acids whose carbon number is 12, 14, 16, or 18, more specifically, lauric acid, myristic acid, palmitic acid, and stearic acid, are suitable. Salts of saturated aliphatic acids whose carbon number is equal to or less than 11 have relatively stronger odor, and therefore, are not suitable for an image forming instrument which uses the fixation fluid and is used in an office or home. On the other hand, salts of saturated aliphatic acids whose carbon number is equal to or greater than 19 have relatively lower solubility in water and significantly degrade the leaving stability of a fixation fluid. Salts of saturated aliphatic acids which may be derived from these saturated aliphatic acids are used as a foaming agent singularly or in combination.
Also, as an aliphatic acid used for a salt of unsaturated aliphatic acid, unsaturated aliphatic acids whose carbon number is 18 and double-bond number is 1 through 3 are desirable. Specifically, oleic acid, linoleic acid, and linolenic acid are suitable. If the double-bond number is equal to or greater than 4, the reactivity is relatively high, and therefore, the leaving stability of a fixation fluid is degraded. Salts of unsaturated aliphatic acids which may be derived from these unsaturated aliphatic acids are used as a foaming agent singularly or in combination. Also, the salt of saturated aliphatic acid and the salt of unsaturated aliphatic acid may be mixed and used as a foaming agent.
Furthermore, when the salt of saturated aliphatic acid or the salt of unsaturated aliphatic acid is used as a foaming agent for the fixation fluid, sodium salts, potassium salts and amine salts are desirable. After a fixation device is powered on, it is important to quickly provide a condition capable of fixing, in view of the commercial value of a fixation device. In order to provide a condition capable of fixing in a fixation device, it is necessary for a fixation fluid to be suitable foam-like one. Since the above-mentioned salts of aliphatic acids may be foamed quickly, a condition capable of fixing may be provided within a short time period after the power-on of the fixation device. Particularly, if an amine salt is used, the fixation fluid is foamed within relatively shorter time period when a shearing force is applied to the fixation fluid, so that a foam-like fixation fluid may be easily produced and a condition capable of fixing may be provided within a relatively shorter time period after a fixation device is powered on.
Moreover, it is desirable that the thickness of a foam-like fixation fluid layer at application area is greater than the thickness of a resin fine particle layer in order to prevent the offset. Also, it is desirable for an air bubble to be larger than a resin fine particle in order to easily adhere to the resin fine particle. When the resin fine particle is a toner particle, the size of the toner particle is about 4 μm-about 10 μm in a dry electrophotographic process. Since the thickness of an unfixed toner layer on a paper medium is about 10 μm-30 μm, it is desirable that the size of an air bubble contained in a liquid containing a softening agent is about 5 μm-about 30 μm.
Also, it is desirable that a dilution solvent is aqueous. The dilution configuration may be a configuration such that a softening agent is dissolved in a dissolution solvent, a configuration of O/W emulsion such that a softening agent is oily and a dilution solvent is aqueous, or a configuration of W/O emulsion such that a softening agent is oily and a dilution solvent is aqueous. Particularly, the configuration such that a softening agent is dissolved in a dilution solvent is desirable since it is excellent in the stability thereof during long-term storage.
Furthermore, a configuration such that a gas which is in a gas phase under atmospheric pressure or an atmospheric component is dissolved or dispersed in a liquid containing a softening agent is desirable in a configuration of storing a fixation fluid in a high-pressure closed container. As a gas which is in a gas phase under atmospheric pressure, aliuphatic hydrocarbons, for example, propane, butane, pentane, hexane, and dimethyl ether are suitable. As an atmospheric gas component, for example, nitrogen gas and argon gas are suitable. In such a configuration, a device for supplying a foam-like fixation fluid to an application member is not simplified or required since a high pressure gas is used, and a fixation device may be easily miniaturized since a device for mechanically applying a shearing force to a fixation fluid or a device for supplying a foam-like fixation fluid to an application member may be simplified.
Also, a softening agent in which softening is conducted by dissolving or swelling a resin includes an aliphatic ester. The aliphatic ester is excellent in a dissolving property or swelling property for dissolving or swelling at least one portion of a resin contained in, for example, toner.
Furthermore, it is preferable that the acute oral toxicity LD50 of a softening agent is greater than 3 g/kg, more preferably, is 5 g/kg, from the viewpoint of the safety thereof for a human body. The safety of aliphatic esters for a human body is high so that they are frequently used as cosmetic materials.
Also, since toner fixation on a recording medium is conducted in an instrument which is frequently used in a closed environment and a softening agent remains in toner after fixation of the toner on a recording medium, it is preferable that fixation of toner on a recording medium involves no generation of a volatile organic compound (VOC) or unpleasant odor. That is, it is preferable that a softening agent includes no volatile organic compound or a material causing unpleasant odor. Aliphatic esters have high boiling points and low volatilities and no irritating odor, compared with commonly used organic solvents (for example, toluene, xylene, methyl ethyl ketone, ethyl acetate).
Additionally, as a practical measure for odor measurement which may measure odor with a high precision in, for example, an office environment, an odor intensity index (10× log (dilution strength of a substance at which the odor of the substance is not sensed)) based on a triangle odor bag method that is a sensory measurement may be used as an index of odor intensity. Also, it is preferable that the odor intensity index of an aliphatic ester contained in a softening agent is equal to or less than 10. In this case, unpleasant odor is not sensed in a usual office environment. Furthermore, it is preferable that another fluid material contained in the fixation fluid, as well as the softening agent, also has no unpleasant odor or no irritating odor.
In the fixation fluid according to an embodiment of the present invention, the aliphatic ester preferably includes a saturated aliphatic ester. When the aliphatic ester includes a saturated aliphatic ester, the preservation stability of a softening agent (the resistance thereof to, for example, oxidation or hydrolysis) may be improved. Also, the safety of saturated aliphatic esters for a human body is high and many of saturated aliphatic esters may dissolve or swell a resin contained in toner within one second. Furthermore, saturated aliphatic esters may reduce the stickiness of a toner provided on a recording medium. It is considered that this is because a saturated aliphatic ester forms an oily membrane on the surface of dissolved or swelled toner.
Therefore, in a fixation fluid according to an embodiment of the present invention, the saturated aliphatic ester preferably includes a compound represented by a general formula of
R1COOR2,
wherein R1 is an alkyl group whose carbon number is equal to or greater than 11 and equal to or less than 14 and R2 is a linear or branched alkyl group whose carbon number is equal to or greater than 1 and equal to or less than 6.
When the saturated aliphatic ester includes a compound represented by a general formula of R1COOR2, wherein R1 is an alkyl group whose carbon number is equal to or greater than 11 and equal to or less than 14 and R2 is a linear or branched alkyl group whose carbon number is equal to or greater than 1 and equal to or less than 6, the dissolving property or swelling property thereof for a resin contained in toner may be improved. Also, the odor intensity index of the compound described above is equal to or less than 10 and the compound described above has no unpleasant odor and no irritating odor.
As an aliphatic monocarboxylate ester which is the compound described above, for example, ethyl laurate, hexyl laurate, ethyl tridecylate, isopropyl tridecylate, ethyl myristate, and isopropyl myristate may be provided. Many of these aliphatic monocarboxylate esters which are the compounds described above are soluble in an oily solvent but are insoluble in water. Therefore, in regard to many of the aliphatic monocarboxylate esters which are the compounds described above, a fixation fluid with a configuration of dissolution or micro-emulsion is provided by containing a glycol as a dissolution auxiliary in an aqueous solvent.
Also, in a fixation fluid according to an embodiment of the present invention, the aliphatic ester preferably includes an aliphatic dicarboxylate ester. When the aliphatic ester includes an aliphatic dicarboxylate ester, a resin contained in toner may be dissolved or swelled for a shorter time period. For example, it is desirable that a time period for which a fixation fluid is provided onto unfixed toner on a recording medium and the toner fixes on the recording medium is within 1 second in high speed character printing of approximately 60 ppm. When the aliphatic ester includes an aliphatic dicarboxylate ester, a time period required for providing a fixation fluid to, for example, unfixed toner on a recording medium and fixing the toner on the recording medium may be within 0.1 second. Furthermore, since a resin contained in toner may be dissolved or swelled by addition of a smaller amount of a softening agent, the content of a softening agent contained in a fixation fluid may be reduced.
Therefore, in a fixation fluid according to an embodiment of the present invention, the aliphatic dicarboxylate ester preferably includes a compound represented by a general formula of
R3(COOR4)2,
wherein R3 is an alkylene group whose carbon number is equal to or greater than 3 and equal to or less than 8 and R4 is a linear or branched alkyl group whose carbon number is equal to or greater than 3 and equal to or less than 5.
When the aliphatic dicarboxylate ester includes a compound represented by a general formula of R3(COOR4)2, wherein R3 is an alkylene group whose carbon number is equal to or greater than 3 and equal to or less than 8 and R4 is a linear or branched alkyl group whose carbon number is equal to or greater than 3 and equal to or less than 5, the dissolving property or swelling property thereof for a resin contained in toner may be improved. Also, the odor intensity index of the compound described above is equal to or less than 10 and the compound described above has no unpleasant odor and no irritating odor.
As an aliphatic dicarboxylate ester which is the compound described above, for example, 2-ethylhexyl succinate, dibutyl adipate, diisobutyl adipate, diisopropyl adipate, diisodecyl adipate, diethyl sebacate, and dibutyl sebacate may be provided. Many of these aliphatic dicarboxylate esters which are the compounds described above are soluble in an oily solvent but are insoluble in water. Therefore, a fixation fluid with a configuration of dissolution or micro-emulsion is provided by containing a glycol as a dissolution auxiliary in an aqueous solvent.
Furthermore, in a fixation fluid according to an embodiment of the present invention, the aliphatic ester preferably includes a dialkoxyalkyl aliphatic dicarboxylate. When the aliphatic ester includes a dialkoxyalkyl aliphatic dicarboxylate, the fixation property of toner on a recording medium may be improved.
In a fixation fluid according to an embodiment of the present invention, the dialkoxyalkyl aliphatic dicarboxylate preferably includes a compound represented by a general formula of
R5(COOR6—O—R7)2,
wherein R5 is an alkylene group whose carbon number is equal to or greater than 2 and equal to or less than 8, R6 is an alkylene group whose carbon number is equal to or greater than 2 and equal to or less than 4, and R7 is an alkyl group whose carbon number is equal to or greater than 1 and equal to or less than 4.
When the dialkoxyalkyl aliphatic dicarboxylate includes a compound represented by a general formula of R5(COOR6—O—R7)2, wherein R5 is an alkylene group whose carbon number is equal to or greater than 2 and equal to or less than 8, R6 is an alkylene group whose carbon number is equal to or greater than 2 and equal to or less than 4, and R7 is an alkyl group whose carbon number is equal to or greater than 1 and equal to or less than 4, the dissolving property or swelling property thereof for a resin contained in toner may be improved. Also, the odor intensity index of the compound described above is equal to or less than 10 and the compound described above has no unpleasant odor and no irritating odor.
As a dialkoxyalkyl aliphatic dicarboxylate which is the compound described above, for example, diethoxyethyl succinate, dibutoxyethyl succinate, diethoxyethyl adipate, dibutoxyethyl adipate, and diethoxyethyl sebacate may be provided. Many of these dialkoxyalkyl aliphatic dicarboxylates may be used in a fixation fluid with a configuration of dissolution or micro-emulsion which is provided by containing a glycol as a dissolution auxiliary in an aqueous solvent.
Additionally, the fine particle containing a resin which is an object to be fixed is not limited to a toner particle and is any of particles containing a resin. For example, it may be a resin fine particle containing an electrically conductive material. Also, the recording medium is not limited to a recording paper sheet and may be, for example, any of metallic, resinous, and ceramic ones. However, the recording medium desirably has a permeability of a fixation fluid, and when the substrate of a medium has no fluid permeability, a medium having a fluid permeating layer on the substrate thereof is desirable. Also, the form of a recording medium is not limited to a sheet shape and may be a solid having a planar or curved surface.
Among the fine particles containing a resin, toner particles used in an electrophotographic process provide the most efficient fixation in combination with a fixation fluid according to an embodiment of the present invention. Toner contains a coloring agent, a charge controlling agent, and a resin such as a binder resin and a releasing agent. A resin contained in toner is not particularly limited. As a preferable resin, for example, polystyrene resins, styrene-acryl copolymer resins, and polyester resins are provided and as a releasing agent, for example, wax components such as carnauba wax and polyethylenes are provided. Toner may contain, for example, a publicly known coloring agent, charge controlling agent, flowability providing agent, or additive as well as a binder resin. Also, it is preferable that toner is water-repellent-treated by retaining a hydrophobic fine particle such as a hydrophobic silica or hydrophobic titanium oxide having a methyl group on the surface of the toner particle. Among the media, a recording medium is not particularly limited, and for example, a paper one, a cloth one, and a plastic film such as an OHP sheet having a liquid permeating layer are provided. The term “oily” in an embodiment of the present invention means a property such that solubility in water at room temperature (20° C.) is equal to or less than 0.1% by weight.
Also, it is desirable that a foam-like fixation fluid preferably has a sufficient affinity with a water-repellent-treated toner particle. Herein, the term “affinity” means the degree of the extension-wetting of a liquid on the surface of a solid when the liquid contacts the solid. That is, it is preferable that a foam-like fixation fluid exhibits a sufficient wetting property to a water-repellent-treated toner. The toner surface that is water-repellent-treated with hydrophobic fine particles such as hydrophobic silica particles and hydrophobic titanium oxide particles is covered with methyl groups present on the hydrophobic silica particles or the hydrophobic titanium oxide particles, and has a surface energy of about 20 mN/m. In fact, since the whole of the water-repellent-treated toner surface is not completely covered with hydrophobic fine particles, it is guessed the surface energy of the water-repellent-treated toner is about 20-30 mN/m. Therefore, it is preferable that the surface tension of a foam-like fixation fluid is 20-30 mN/m in order to have affinity (or a sufficient wetting property) with water-repellent toner.
When an aqueous solvent is used, it is preferable that a surfactant is added such that the surface tension is 20-30 mN/m. Also, in the case of an aqueous solvent, it is desirable to contain a mono- or poly-hydric alcohol. These materials have an advantage such that the stability of air bubbles in a foam-like fixation fluid is improved so as to be hardly subjected to bubble breaking. For example, monohydric alcohols such as cetanol and polyhydric alcohols such as glycerin, propylene glycol, and 1,3-butylene glycol are desirable. Also, inclusion of the monohydric or polyhydric alcohol provides an effect of prevention of curling of a recording medium such as a paper sheet.
Also, it is desirable to form an O/W emulsion or W/O emulsion by containing an oily component in a fixation fluid in order to improve the permeability thereof or prevent curling of a medium such as a paper sheet, and in this case, as a specific dispersing agent, desirable are sorbitan aliphatic esters such as sorbitan monooleate, sorbitan monostearate, and sorbitan sesquiolate and sucrose esters such as sucrose laurates and sucrose stearates.
Herein, as a device for dissolving or micro-emulsion-dispersing a softening agent in a fixation fluid, for example, a mechanically agitation device based on a rotary wing such as a homomixer and a homogenizer and a vibrating device such as an ultrasonic homogenizer are provided. In any of the cases, a softening agent is dissolved or micro-emulsion-dispersed by applying a strong shearing force to a fixation fluid.
Also, the toner fixation device may have a pair of smoothing rollers (hard rollers) for pressurizing a toner dissolved or swelled by an agent for dissolving or swelling at least one portion of a resin contained in the toner after a fixation fluid according to an embodiment of the present invention is supplied onto the toner. The dissolved or swelled toner is pressurized by the pair of smoothing rollers (hard rollers) so as to smooth the surface of a dissolved or swelled toner layer, so that the toner may be provided with glossiness. Furthermore, the fixation property of a dissolved or swelled toner on a recording medium may be improved by pushing the toner into the recording medium.
In an image forming apparatus according to one embodiment of the present invention, an image of a toner containing a resin is formed on a recording medium by using an image forming method as described above. Therefore, due to an image forming apparatus according to an embodiment of the present invention, each of an image forming method and image forming apparatus which are capable of fixing toner on a recording medium more efficiently may be provided as described above.
An image forming apparatus 90 shown in
A recording paper sheet 104 as a recording medium is guided to a secondary transcription part by a pair of paper sheet feeding rollers 105, and a toner image is transcribed by pushing the secondary transcription belt 102 onto the intermediate transcription belt 91 when the toner image is transcribed on the recording paper sheet 104. The recording paper sheet 104 on which the toner image is transcribed is conveyed by the secondary transcription belt 102 and the unfixed toner image transcribed on the recording paper sheet 104 is fixed by a toner fixing device according to an embodiment of the present invention, which controls the thickness of a foam-like fixation fluid layer based on image information from an light exposure device which is not shown in the figure. That is, a foam-like fixation fluid according to an embodiment of the present invention which is supplied from the toner fixing device in which the layer thickness of a foam-like fixation fluid layer has been controlled based on image information, for example, a color image or a black solid image, from the light exposure devices which are not shown in the figure, is provided to the unfixed toner image transcribed on the recording paper sheet 104, and the unfixed toner image is fixed on the recording paper sheet 104 by an agent for dissolving or swelling at least one portion of a resin in the toner (a softening agent) which is contained in the foam-like fixation fluid.
Next, the image forming unit is described below. As shown in
Next, specific examples of a fixation fluid and fixation according to an embodiment of the present invention are described below.
Liquid Containing a Softening Agent
Dilution solvent: Ion-exchanged water, 70% by weight
Softening agent: diethoxyethyl succinate (Croda Inc., Croda DES), 10% by weight
Thickening agent: glycerin, 5% by weight
Bubble-increasing agent: coconut oil fatty acid diethanolamide (Komikado DEA), 2% by weight
Foaming agent: sodium palmitate, 5% by weight; sodium myristate, 3% by weight; and sodium stearate, 2% by weight
Dispersing agent: POE (20) lauryl sorbitan (Kao corporation, RHEODOL TW-S120V), 2% by weight; and polyethyleneglycol monostearate (Kao EMANON 3199), 1% by weight
Additionally, the dispersing agents were used to improve the solubility of the softening agent in the dilution solvent.
On the component ratios, first, a solution was prepared by mixing and agitating at a solution temperature of 90° C. except the softening agent. Then, the softening agent was mixed to prepare a fixation fluid in which the softening agent was dissolved (a formulated solution before foaming it). Additionally, the dispersing agents were additives for improving the solubility of, for example, the softening agent.
Enclosing in a High-Pressure Closed Container
Liquid containing a softening agent: 95% by weight
Gas which is in a gas phase under atmospheric pressure (LPG): 5% by weight
On the component ratios, they were mixed in a closed container having an actuator part for atmospheric releasing and a nozzle part and an O/W emulsion liquid in which the gas which was in a gas phase under atmospheric pressure was dispersed was prepared by agitation (wherein the softening agent was dissolved in the fixation fluid).
<Application Device>
As shown in
Pressurizing roller: aluminum roller (φ 30)
Application roller: SUS roller baking-coated with a PFA resin (φ 30)
Blade: SUS sheet
Paper sheet conveying speed: 200 mm/s
Loading between pressurizing roller and application roller: two patterns, that is, 10 N and 200 N at one side
<Experimental Results>
Then, the foam-like fixation fluid ejected from the high-pressure closed container was supplied to the gap between the blade and the application roller through a tube. The bulk density of the foam-like fixation fluid was 0.07 g/cm3.
In
Additionally, a significant bubble breaking in the foam-like fixation fluid was hardly found within a short time period (about 1 minute) during the observation of the surface of the application roller by the optical microscope.
Ipsio Color CX8800 (produced by Ricoh Company Ltd.) was used as a printer. Roller application was conducted on a PPC paper sheet (Ricoh T-6200) by using a fixation device as shown in
Additionally, the criteria of the experimental results are as follows (Similar ones apply to another specific examples and a comparative example).
Fixation property (Optical density of the contaminant on the waste); ◯: Optical density equal to or less than 0.3, Δ: Optical density from 0.3 to 0.5, X: Optical density equal to or greater than 0.5
Offset property (Adhesion of toner on tape in visual observation); ◯: Almost no toner adhesion, Δ: Slight toner adhesion, X: Significant toner adhesion
Presence or Absence of image irregularity; ◯: Almost no irregularity or good, Δ: An irregularity(ies) on a portion of an image, X: Irregularities over the entire of an image
Curling; ◯: Equal to or less than 20 mm, Δ: From 20 mm to 30 mm, X: Equal to or greater than 30 mm
The results of evaluations of the fixation property, offset property, presence or absence of an image irregularity, and curling of a paper sheet on the conditions of the foam-like fixation fluid in Table 1 are shown in Table 2 when the loading on the application roller at one side thereof was 10 N or 200 N.
As seen from Table 2, extremely good fixation may be possible by appropriately controlling the layer thickness of a foam-like fixation fluid on an application roller depending on a pressure applied on the contact area between a recording medium and the application roller.
Liquid Containing a Softening Agent
Dilution solvent: Ion-exchanged water, 70% by weight
Softening agent: diethoxyethyl succinate (Croda Inc., Croda DES), 10% by weight
Thickening agent: glycerin, 5% by weight
Bubble increasing agent: coconut oil fatty acid diethanolamide (Komikado DEA), 2% by weight
Foaming agent: potassium palmitate, 5% by weight; potassium myristate, 3% by weight; and potassium stearate, 2% by weight
Dispersing agent: POE (20) lauryl sorbitan (Kao corporation, RHEODOL TW-S120V), 2% by weight; and polyethyleneglycol monostearate (Kao EMANON 3199), 1% by weight
On the component ratios, first, a solution was prepared by mixing and agitating at a solution temperature of 90° C. except the softening agent. Then, the softening agent was mixed to prepare a fixation fluid in which the softening agent was dissolved (a formulated solution before foaming it).
Enclosing in a High-Pressure Closed Container
Liquid containing a softening agent: 95% by weight
Gas which is in a gas phase under atmospheric pressure (LPG): 5% by weight
On the component ratios, they were mixed in a closed container having an actuator part for atmospheric releasing and a nozzle part and an O/W emulsion liquid in which the gas which was in a gas phase under atmospheric pressure was dispersed was prepared by agitation (wherein the softening agent was dissolved in the fixation fluid).
<Application Device>
Similarly to specific example 1, as shown in
<Experimental Results>
Then, the foam-like fixation fluid ejected from the high-pressure closed container was supplied to the gap between the blade and an application roller through a tube. The bulk density of the foam-like fixation fluid was 0.09 g/cm3.
In
Additionally, a significant bubble breaking in the foam-like fixation fluid was hardly found within a short time period (about 1 minute) during the observation of the surface of the application roller by an optical microscope.
Ipsio Color CX8800 (produced by Ricoh Company Ltd.) was used as a printer. Roller application was conducted on a PPC paper sheet (Ricoh T-6200) by using a fixation device as shown in
As seen from Table 4, extremely good fixation may be possible by appropriately controlling the layer thickness of a foam-like fixation fluid on an application roller depending on a pressure applied on the contact area between a recording medium and the application roller.
Liquid Containing a Softening Agent
Dilution solvent: Ion-exchanged water, 66% by weight
Softening agent: diethoxyethyl succinate (Croda Inc., Croda DES), 10% by weight
Thickening agent: glycerin, 5% by weight
Bubble increasing agent: coconut oil fatty acid diethanolamide (Komikado DEA), 2% by weight
Foaming agent: A fatty acid amine (a palmitic acid raw material, 5% by weight; a myristic acid raw material, 3% by weight; a stearic acid raw material, 2% by weight; and triethanolamine, 4% by weight), 14% by weight
Dispersing agent: POE (20) lauryl sorbitan (Kao corporation, RHEODOL TW-S120V), 2% by weight; and polyethyleneglycol monostearate (Kao EMANON 3199), 1% by weight
On the component ratios, first, ion-exchanged water in which the triethanolamine had preliminarily been dissolved was heated at a liquid temperature of 90° C. and the palmitic acid raw material, the myristic acid raw material, and the stearic acid raw material were added, respectively, so as to prepare the fatty acid amine which was a foaming agent. Subsequently, the residual components except the softening agent were mixed and agitated so as to prepare a solution. Then, the softening agent was mixed to prepare a fixation fluid in which the softening agent was dissolved (a formulated solution before foaming it).
Enclosing in a High-Pressure Closed Container
Liquid containing a softening agent: 95% by weight
Gas which is in a gas phase under atmospheric pressure (LPG): 5% by weight
On the component ratios, they were mixed in a closed container having an actuator part for atmospheric releasing and a nozzle part and an O/W emulsion liquid in which the gas which was in a gas phase under atmospheric pressure was dispersed was prepared by agitation (wherein the softening agent was dissolved in the fixation fluid).
<Application Device>
Similarly to specific example 1, as shown in
<Experimental Results>
Then, the foam-like fixation fluid ejected from the high-pressure closed container was supplied to the gap between the blade and an application roller through a tube. The bulk density of the foam-like fixation fluid was 0.07 g/cm3.
In
Additionally, a significant bubble breaking in the foam-like fixation fluid was hardly found within a short time period (about 1 minute) during the observation of the surface of the application roller by an optical microscope.
Ipsio Color CX8800 (produced by Ricoh Company Ltd.) was used as a printer. Roller application was conducted on a PPC paper sheet (Ricoh T-6200) by using a fixation device as shown in
As seen from Table 6, extremely good fixation may be possible by appropriately controlling the layer thickness of a foam-like fixation fluid on an application roller depending on a pressure applied on the contact area between a recording medium and the application roller.
Instead of the salt of fatty acid as a foaming agent, a polyoxyethylene-type surfactant which is a nonionic surfactant was used.
Liquid Containing a Softening Agent
Dilution solvent: Ion-exchanged water, 79% by weight
Softening agent: diethoxyethyl succinate (Croda Inc., Croda DES), 10% by weight
Thickening agent: glycerin, 5% by weight
Bubble increasing agent: coconut oil fatty acid diethanolamide (Komikado DEA), 2% by weight
Foaming agent: polyoxyethylene-type surfactant (Nippon Oil & Fats Co., Ltd.), 1% by weight
Dispersing agent: POE (20) lauryl sorbitan (Kao corporation, RHEODOL TW-S120V), 2% by weight; and polyethyleneglycol monostearate (Kao EMANON 3199), 1% by weight
On the component ratios, first, a solution was prepared by mixing and agitating at a solution temperature of 25° C. except the softening agent. Then, the softening agent was mixed to prepare a fixation fluid in which the softening agent was dissolved (a formulated solution before foaming it).
Enclosing in a High-Pressure Closed Container
Liquid containing a softening agent: 95% by weight
Gas which is in a gas phase under atmospheric pressure (LPG): 5% by weight
On the component ratios, they were mixed in a closed container having an actuator part for atmospheric releasing and a nozzle part and an O/W emulsion liquid in which the gas which was in a gas phase under atmospheric pressure was dispersed was prepared by agitation (wherein the softening agent was dissolved in the fixation fluid).
<Application Device>
Similarly to specific examples 1, 2 and 3, as shown in
<Experimental Results>
Then, the foam-like fixation fluid ejected from the high-pressure closed container was supplied to the gap between the blade and an application roller through a tube. The bulk density of the foam-like fixation fluid was 0.20 g/cm3.
In
Additionally, bubbles were successively subjected to bubble breaking within a short time period (about 1 minute) during the observation thereof by a microscope and foaming stability was not good.
Similarly to specific example 1, Ipsio Color CX8800 (produced by Ricoh Company Ltd.) was used as a printer. Roller application was conducted on a PPC paper sheet (Ricoh T-6200) by using a fixation device as shown in
As seen from Table 8, in the case of a foam-like fixation fluid including a foaming agent except salts of fatty acids, a significant offset, image irregularity or paper sheet curling was caused even if the layer thickness of the foam-like fixation fluid on an application roller was changed depending on a pressure applied on the contact area between a recording medium and the application roller.
Liquid Containing a Softening Agent
Dilution solvent: Ion-exchanged water, 70% by weight
Softening agent: diethoxyethyl succinate (Croda Inc., Croda DES), 10% by weight
Thickening agent: glycerin, 5% by weight
Bubble increasing agent: coconut oil fatty acid diethanolamide (Komikado DEA), 2% by weight
Foaming agent: potassium palmitate, 5% by weight; potassium myristate, 3% by weight; and potassium stearate, 2% by weight
Dispersing agent: POE (20) lauryl sorbitan (Kao corporation, RHEODOL TW-S120V), 2% by weight; and polyethyleneglycol monostearate (Kao EMANON 3199), 1% by weight
On the component ratios, first, a solution was prepared by mixing and agitating at a solution temperature of 90° C. except the softening agent. Then, the softening agent was mixed to prepare a fixation fluid in which the softening agent was dissolved (a formulated solution before foaming it).
<Application Device>
As shown in
<Experimental Results>
The number of revolution for the agitation was 3,000 rpm and the agitation time period was 1 minute. Then, the bulk density of the foam-like fixation fluid was 0.10 g/cm3.
In
Additionally, a bubble breaking in the foam-like fixation fluid was hardly found within a short time period (about 1 minute) during the observation of the surface of the application roller by an optical microscope.
Ipsio Color CX8800 (produced by Ricoh Company Ltd.) was used as a printer. Roller application was conducted on a PPC paper sheet (Ricoh T-6200) by using a fixation device as shown in
As seen from Table 10, extremely good fixation may be possible by appropriately controlling the layer thickness of a foam-like-fixation fluid on an application roller depending on a pressure applied on the contact area between a recording medium and the application roller.
Liquid Containing a Softening Agent
Dilution solvent: Ion-exchanged water, 58% by weight
Softening agent: diisobutyl adipate (Higher. Alcohol Industry Co., Ltd., KAK-DiBA), 7% by weight
Thickening agent: glycerin, 20% by weight
Bubble increasing agent: coconut oil fatty acid diethanolamide (Komikado DEA), 2% by weight
Foaming agent: potassium palmitate, 5% by weight; potassium myristate, 3% by weight; and potassium oleate, 2% by weight
Dispersing agent: POE (20) lauryl sorbitan (Kao corporation, RHEODOL TW-S120V), 2% by weight; and polyethyleneglycol monostearate (Kao EMANON 3199), 1% by weight
On the component ratios, first, a solution was prepared by mixing and agitating at a solution temperature of 90° C. except the softening agent. Then, the softening agent was mixed to prepare a fixation fluid in which the softening agent was dissolved (a formulated solution before foaming it).
<Application Device>
As shown in
<Experimental Results>
The number of revolution for the agitation was 3,000 rpm and the agitation time period was 1 minute. Then, the bulk density of the foam-like fixation fluid was 0.12 g/cm3.
In
Additionally, a bubble breaking in the foam-like fixation fluid was hardly found within a short time period (about 1 minute) during the observation of the surface of the application roller by an optical microscope.
Ipsio Color CX8800 (produced by Ricoh Company Ltd.) was used as a printer. Roller application was conducted on a PPC paper sheet (Ricoh T-6200) by using a fixation device as shown in
As seen from Table 12, extremely good fixation may be possible by appropriately controlling the layer thickness of a foam-like fixation fluid on an application roller depending on a pressure applied on the contact area between a recording medium and the application roller.
Typical embodiments (1) to (29) of the present invention are described below.
One of the typical embodiments of the present invention relates to one selected from the group consisting of a fixation device, a fixation method, an image formation apparatus, an image forming method, and a fixation fluid. More particularly, one of the typical embodiments of the present invention may relates to a fixation fluid configured to fix on a medium a fine particle which contains a resin or a device configured to fix a toner which is a fine particle that contains a resin.
Embodiment (1) is a fixation device configured to fix on a medium a resin fine particle that contains a resin, by providing a fixation fluid on the resin fine particle on the medium which fixation fluid contains a softening agent that softens the resin fine particle by dissolving or swelling at least one portion of the resin, water and a foaming agent that comprises a salt of aliphatic acid, wherein the fixation device comprises a foam-like fixation fluid producing part configured to produce a foam-like fixation fluid, a layer thickness controlling part configured to control a layer thickness of the produced foam-like fixation fluid, and a provision part configured to provide the layer-thickness-controlled foam-like fixation fluid on the resin fine particle on the medium.
Herein, the embodiment (1) as described above makes it possible to prevent offset onto a member of the provision part (e.g. in contact provision), to attain a small amount provision without disturbing a resin fine particle on a medium, and/or to provide fixation in which curling of a recording medium such as a paper sheet is not easy to occur and which is excellent in fixation responsibility.
Embodiment (2) is the fixation device as described in embodiment (1) above, wherein the foam-like fixation fluid producing part is configured to apply a shearing force to the fixation fluid so as to contain an air bubble in the fixation fluid and produce the foam-like fixation fluid.
Herein, embodiment (2) makes it possible to produce a stable foam-like fixation fluid to improve reliability.
Embodiment (3) is the fixation device as described in embodiment (1) above, wherein the foam-like fixation fluid producing part comprises a closed container in which a fixation fluid that contains an atmospheric component or an alkane that is gas under atmospheric pressure is closed under atmospheric or higher pressure, an actuator member configured to release the fixation fluid to atmosphere, and a nozzle member configured to eject the fixation fluid.
Herein, embodiment (3) makes it possible to produce a foam-like fixation fluid easily without using a mechanical apparatus so as to miniaturize the device or to attain weight-saving thereof.
Embodiment (4) is the fixation device as described in embodiment (1) above, wherein the layer thickness controlling part configured to control a layer thickness of the foam-like fixation fluid depending on a contact pressure in a case where the provision part is a direct provision part configured to provide the foam-like fixation fluid to the medium such that it contacts the medium.
Herein, embodiment (4) makes it possible to adjust a contact pressure of the direct provision part so as to control a layer thickness of a foam-like fixation fluid to be in an appropriate range, whereby a fixation device may be provided in which fixation that causes no offset and is excellent in fixation responsibility is allowed.
Embodiment (5) is the fixation device as described in embodiment (1) or (4) above, wherein the layer thickness controlling part is configured to control a layer thickness of the foam-like fixation fluid depending on a thickness of a layer of the resin fine particle on the medium.
Herein, embodiment (5) makes it possible to provide a fixation device in which fixation that causes no offset and is excellent in fixation responsibility is allowed.
Embodiment (6) is the fixation device as described in any of embodiments (1) through (5) above, wherein the provision part is an application roller.
Herein, the embodiment (6) provides a more preferable fixation device.
Embodiment (7) is the fixation device as described in any of embodiments (1) through (5) above, wherein the provision part is an application belt.
Herein, the embodiment (7) provides a more preferable fixation device.
Embodiment (8) is a fixation method configured to fix on a medium a resin fine particle that contains a resin, by producing a fixation fluid in a foam-like condition which fixation fluid contains a softening agent that softens the resin fine particle by dissolving or swelling at least one portion of the resin, water and a foaming agent that comprises a salt of aliphatic acid, and controlling a layer thickness of a produced foam-like fixation fluid while it is provided on the resin fine particle on the medium.
Herein, the embodiment (8) as described above makes it possible to disturb no resin fine particle that contains a resin, such as a toner, on a medium, such as a paper sheet, and/or to quickly conduct fixation of a resin fine particle on a medium after applying a fixation fluid on the medium to which the resin fine particle adheres, whereby reliability of fixation may be improved.
Embodiment (9) is the fixation method as described in embodiment (8) above, wherein a shearing force is applied to the fixation fluid so as to contain an air bubble in the fixation fluid and produce the foam-like fixation fluid.
Herein, embodiment (9) makes it possible to produce a stable foam-like fixation fluid to improve reliability.
Embodiment (10) is the fixation method as described in embodiment (8) above, wherein a fixation fluid that contains an atmospheric component or an alkane that is gas under atmospheric pressure is closed under atmospheric or higher pressure and the fixation fluid is released to atmosphere, so as to produce a foam-like fixation fluid.
Herein, embodiment (10) makes it possible to produce a foam-like fixation fluid easily without using a mechanical apparatus so as to miniaturize the device or to attain weight-saving thereof.
Embodiment (11) is the fixation method as described in embodiment (8) above, wherein a layer thickness of the foam-like fixation fluid is controlled depending on a contact pressure in a case where the foam-like fixation fluid is provided to the medium such that it contacts the medium.
Herein, embodiment (11) makes it possible to control a layer thickness of a foam-like fixation fluid to be in an appropriate range, depending on the contact pressure, whereby a fixation device may be provided in which fixation that causes no offset and is excellent in fixation responsibility is allowed.
Embodiment (12) is the fixation method as described in embodiment (8) or (11) above, wherein a layer thickness of the foam-like fixation fluid is controlled depending on a thickness of a layer of the resin fine particle on the medium.
Herein, embodiment (12) makes it possible to allow for fixation that causes no offset and is excellent in fixation responsibility.
Embodiment (13) is an image forming apparatus which comprises an image forming part configured to form an unfixed toner image on a medium by conducting an electrostatic recording process with a toner in which a resin fine particle contains a coloring agent, and a fixation part configured to fix the unfixed toner image on the medium, with the fixation device as described in any of embodiments (1) through (7).
Herein, embodiment (13) makes it possible to provide an image forming apparatus to disturb no fine particle that contains a resin, such as a toner, on a medium, such as a paper sheet, to quickly conduct fixation of a resin fine particle on a medium after applying a fixation fluid on the medium to which the resin fine particle adheres, to allow for a small amount of application such that residual liquid feeling is not caused on a medium, to attain non-heating fixation and low electric power consumption, and/or to be in excellent in fixation responsibility.
Embodiment (14) is an image forming method in which an electrostatic recording process is conducted with a toner in which a resin fine particle contains a coloring agent to form an unfixed toner image on a medium, and the unfixed toner image is fixed on the medium, with the fixation method as described in any of embodiments (8) through (12), so as to form an image on the medium.
Herein, embodiment (14) makes it possible to provide an image forming method which attains non-heating-type fixation and low electric power consumption, and/or is in excellent in fixation responsibility.
Embodiment (15) is a fixation fluid configured to fix a resin fine particle on a medium by producing the fixation fluid in a foam-like condition and providing the produced foam-like fixation fluid on the resin fine particle on the medium, the fixation fluid contains a softening agent that softens the resin fine particle by dissolving or swelling at least one portion of the resin fine particle, water and a foaming agent that comprises a salt of aliphatic acid.
Herein, embodiment (15) makes it possible to make an air bubble of a foam-like fixation fluid be smaller, to form an air bubble layer which is excellent in foaming stability and/or suppresses permeation of a fixation fluid to a paper sheet, to make the amount of a fixation fluid applied on a paper sheet as a recording medium be a slight amount thereof, to suppress curling of a paper sheet as a recording medium, and/or to improve fixation responsibility.
Embodiment (16) is the fixation fluid as described in embodiment (15) above, wherein the fixation fluid contains a bubble increasing agent.
Embodiment (17) is the fixation fluid as described in embodiment (16), wherein the bubble increasing agent contains an aliphatic acid-derived alkanolamide-type nonionic surfactant.
Herein, at least one of embodiments (16) and (17) above makes it possible to improve foaming stability so as to suppresses bubble breaking of a foam-like fixation fluid at an area at which a contact application part contacts a recording medium such as a paper sheet, whereby toner offset may be prevented which is caused by bubble breaking and liquefaction of the fixation fluid.
Embodiment (18) is the fixation fluid as described in embodiment (15) above, wherein the salt of aliphatic acid is a single one of, or a mixture of at least one of, salts of saturated aliphatic acids whose carbon numbers are 12, 14, 16 and 18.
Herein, embodiment (18) makes it possible to provide a foam-like fixation fluid whose bubble plateau area is robust and/or to improve foaming stability so as to suppresses bubble breaking of a foam-like fixation fluid at an area at which a contact application part contacts a recording medium such as a paper sheet, whereby toner offset may be prevented which is caused by bubble breaking and liquefaction of the fixation fluid.
Embodiment (19) is the fixation fluid as described in embodiment (15) above, wherein the salts of aliphatic acids comprise a single one of, or a mixture of at least one of, salts of unsaturated aliphatic acids whose carbon numbers are 18 and double-bond numbers are at least one of 1 through 3.
Herein, embodiment (19) makes it possible to improve solubility of the salt of aliphatic acid in water under the environment of low air temperature equal to or less than 20° C. and/or to have an excellent foaming property in a range of a lower air temperature of 5° C.-15° C. to a higher air temperature of 35° C.-45° C., whereby fixation may be stably conducted in a wide range of environmental temperature.
Embodiment (20) is the fixation fluid as described in any of embodiments (15)-(19) above, wherein the salt of aliphatic acid is a sodium salt, a potassium salt, or an amine salt.
Herein, embodiment (19) makes it possible to maintain the solubility in water and/or to conduct fixation stably in a wide range of environmental temperature.
Embodiment (21) is the fixation fluid as described in any of embodiments (15) through (20) above, wherein the fixation fluid contains an atmospheric component or an alkane that is gas under atmospheric pressure is closed under atmospheric or higher pressure.
Herein, embodiment (21) makes it possible to allow for use of a high-pressure closed container and/or to allow for manufacturing of a foam-like fixation fluid that contains a dense and fine air bubble, by dissolving or dispersing a gas which is in a gas phase under atmospheric or less pressure or an atmospheric component in a fixation fluid.
Embodiment (22) is the fixation fluid as described in any of embodiments (15) to (21) above, wherein the softening agent comprises an aliphatic ester.
Herein, embodiment (22) makes it possible to provide a more preferable fixation fluid.
Embodiment (23) is the fixation fluid as described in embodiment (22) above, wherein the aliphatic ester comprises a saturated aliphatic ester.
Herein, embodiment (23) makes it possible to provide a more preferable fixation fluid.
Embodiment (24) is the fixation fluid as described in embodiment (23) above, wherein the saturated aliphatic ester comprises a compound represented by a general formula of R1COOR2, wherein R1 is an alkyl group whose carbon number is equal to or greater than 11 and equal to or less than 14 and R2 is an alkyl group whose carbon number is equal to or greater than 1 and equal to or less than 6.
Herein, embodiment (24) makes it possible to provide a more preferable fixation fluid.
Embodiment (25) is the fixation fluid as described in embodiment (22) above, wherein the aliphatic ester comprises an aliphatic dicarboxylic acid ester.
Herein, embodiment (25) makes it possible to provide a more preferable fixation fluid.
Embodiment (26) is the fixing fluid as described in embodiment (25) above, wherein the aliphatic dicarboxylic acid ester comprises a compound represented by a general formula of R3(COOR4)2, wherein R3 is an alkylene group whose carbon number is equal to or greater than 3 and equal to or less than 8 and R4 is an alkyl group whose carbon number is equal to or greater than 3 and equal to or less than 5.
Herein, embodiment (26) makes it possible to provide a more preferable fixation fluid.
Embodiment (27) is the fixation fluid as described in embodiment (22) above, wherein the aliphatic ester comprises a dialkoxyalkyl aliphatic dicarboxylate.
Herein, embodiment (27) makes it possible to provide a more preferable fixation fluid.
Embodiment (28) is the fixation fluid as described in embodiment (27) above, wherein the dialkoxyalkyl aliphatic dicarboxylate comprises a compound represented by a general formula of R5(COOR6—O—R7)2, wherein R5 is an alkylene group whose carbon number is equal to or greater than 2 and equal to or less than 8, R6 is an alkylene group whose carbon number is equal to or greater than 2 and equal to or less than 4, and R7 is an alkyl group whose carbon number is equal to or greater than 1 and equal to or less than 4.
Herein, embodiment (28) makes it possible to provide a more preferable fixation fluid.
Embodiment (29) is the fixation fluid as described in any of embodiments (15) through (28) above, wherein the fixation fluid comprises a monohydric or polyhydric alcohol.
Herein, embodiment (29) makes it possible to suppress curling of a recording medium such as a paper sheet which contains cellulose.
Additionally, at least one of the typical embodiments of the present invention may be based on an insight or principle such that a foam-like fluid which contains a large quantity of air bubbles may have a significantly low bulk density and/or the influence of the surface tension of a fluid surface or the internal flow property of a fluid, which are properties of a fluid may be significantly reduced by containing a large quantity of air bubbles.
Thus, the typical embodiments of the present invention may provide a fixation fluid for a resin fine particle and a fixation device, fixation method, image forming apparatus and image forming method using the fixation fluid, which fixation fluid makes it possible to disturb no fine particle that contains a resin, such as a toner, on a recording medium, such as a paper sheet, to quickly conduct fixation of a resin fine particle on a medium after applying the fixation fluid on the medium to which the resin fine particle adheres, and/or to attain small amount application such that residual liquid feeling is not caused on a medium.
Although the embodiments and practical examples of the present invention have been specifically described above, the present invention is not limited to the embodiments or practical examples and any of the embodiments or practical examples may be varied or modified without departing from the spirit and scope of the present invention.
The present application claims the benefit of the foreign priority based on Japanese Patent Application No. 2006-234735 filed on Aug. 31, 2006, the entire contents of which are hereby incorporated by reference.
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| 20080063446 A1 | Mar 2008 | US |
