JP2004209799A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain high-quality picture prints by eliminating fixing irregularities of a recording medium resulting from an adhered substance adhered to a face of the opposite side to a contact face of a fixing belt to the recording medium, and carrying out uniform fixing in an inkjet recording device with the fixing belt as a fixing means. <P>SOLUTION: In the inkjet recording device which carries out recording to the recording medium 1 with thermoplastic resin particles, the fixing means 5 is set for fixing the thermoplastic resin particles of the recording medium 1 by heating and pressuring the recording medium 1 after recorded. The fixing means 5 includes a heating roller 5a, a pressuring roller 5e, the fixing belt 5d for fixing by holding the recording medium 1 between the heating roller 5a or the pressuring roller 5e and the fixing belt, and a removing means 70 for removing the adhered substance adhered to the face 5B through contact with the face 5B of the opposite side to the contact face 5A of the fixing belt 5d to the recording medium 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording apparatus having a fixing unit that records on a recording medium having thermoplastic resin particles, and heats and presses the recorded recording medium to fix the thermoplastic resin particles of the recording medium. .
[0002]
[Prior art]
Ink jet recording, in which an image is recorded on a recording medium having thermoplastic resin particles, is performed by heating and pressurizing the recording medium after recording to make the thermoplastic resin particles transparent (fixed), so that the image can be combined with water. It is known that it can prevent bleeding due to contact, improve scratch resistance, and can produce high-quality and high-quality prints close to silver halide photographs.
[0003]
In such ink jet recording, it is important to appropriately make the thermoplastic resin particles of the recording medium after the recording transparent in order to obtain high-quality and high-quality prints. For example, if an attachment such as dust or paper dust adheres to the contact surface of the fixing unit with the recording surface of the recording medium, the fixing unit will not be properly made transparent and may cause a defect on the image surface. There are many. Therefore, conventionally, a cleaning belt made of a sponge roller, a nonwoven fabric, or the like, which is rotated as a cleaning member, is disposed in contact with a surface of a heating roller constituting a fixing unit, so that a contact surface with a recording medium is cleaned. A proposed technique has been proposed (Patent Document 1).
[0004]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-67295
[Problems to be solved by the invention]
On the other hand, as a fixing unit, in addition to a type in which a recording medium is sandwiched between a heating roller and a pressing roller to apply heat and pressure, a fixing unit using a fixing belt stretched between rollers is known. . The fixing unit includes, for example, a pressure roller that wraps a fixing belt between a heating roller and a rotating roller, and that presses the fixing belt toward the heating roller with the fixing belt interposed therebetween. The recording medium is heated and pressurized by the nip between the fixing belt and the pressure roller wound around the heating roller, and then is fixed in a state of sticking to the fixing belt. Satisfactory fixing can be performed as compared with a fixing unit of a fixing type.
[0006]
However, in the fixing unit having such a fixing belt, if an adhering substance such as dust or paper powder adheres to the back side of the fixing belt, that is, the surface opposite to the contact surface with the recording medium, the adhering portion is heated. When it comes between the roller and the pressure roller, there is a possibility that the nip formed between the roller and the pressure roller may have fine irregularities. Further, the irregularities may remain as subtle irregular deformations of the fixing belt itself, resulting in permanent defects. When such irregularities occur, uniform heating and pressurization over the width direction of the fixing belt cannot be performed, and unevenness in transparency occurs due to uneven fixing in the width direction of the recording medium, and image quality is reduced. There is a risk of lowering.
[0007]
Therefore, an object of the present invention is to provide an inkjet recording apparatus having a fixing belt as a fixing unit, to eliminate the fixing unevenness of the recording medium caused by the adhered matter adhered to the surface of the fixing belt opposite to the contact surface with the recording medium, An object of the present invention is to make it possible to obtain a high-quality image print by performing uniform fixing.
[0008]
[Means for Solving the Problems]
The above object is achieved by the following inventions.
[0009]
The invention according to claim 1 includes a fixing unit that performs recording on a recording medium having thermoplastic resin particles, and heats and presses the recording medium after recording to make the thermoplastic resin particles of the recording medium transparent. In the ink jet recording apparatus, the fixing unit includes a heating roller and a pressure roller, a fixing belt that fixes the recording medium by sandwiching the recording medium between the heating roller and the pressure roller, and a recording medium in the fixing belt. And a removing means for contacting the surface opposite to the contact surface of the above to remove the deposits attached to the surface.
[0010]
2. The ink jet recording apparatus according to claim 1, wherein the removing unit contacts the fixing belt at a constant speed on a surface of the fixing belt opposite to a contact surface with a recording medium. Device.
[0011]
The invention according to claim 3 is the ink jet recording apparatus according to claim 1 or 2, wherein the removing unit is an adhesive roller.
[0012]
The invention according to claim 4 is the ink jet recording apparatus according to claim 3, wherein the adhesive roller is made of silicon rubber or butyl rubber having a surface having viscoelasticity.
[0013]
The invention according to claim 5 is the ink jet recording apparatus according to claim 3 or 4, wherein the adhesive roller has a surface hardness of 3 to 60.
[0014]
According to a sixth aspect of the present invention, there is provided the ink jet recording apparatus according to the third, fourth, or fifth aspect, further comprising a cleaning roller that contacts the adhesive roller and cleans a surface of the adhesive roller.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a side view schematically showing the overall configuration of the ink jet recording apparatus according to the present invention.
[0017]
The recording medium 1, which will be described in detail later, is a recording medium having thermoplastic resin particles in a layer structure thereof, and is a drive motor (not shown) in the form of a long roll paper wound in a roll shape. The recording medium 2 is conveyed to the recording unit 2 by being nipped by a first conveying roller pair 10 including a driving roller 11 and a driven roller 12 that are driven to rotate.
[0018]
A recording head 2a is provided in the recording unit 2 so as to be movable in a main scanning direction substantially orthogonal to the transport direction of the recording medium 1, and a predetermined direction is directed from the recording head 2a toward the recording surface 1a of the recording medium 1. By jetting the ink at the timing, a desired image is recorded in cooperation with the conveyance of the recording medium 1 by the first conveyance means 10.
[0019]
The recording medium 1 on which an image is recorded on the recording surface 1 a by the recording head 2 a in the recording unit 2 is cut into a predetermined size by the cutter unit 3. The cut recording medium 1 is conveyed to the switchback unit 4 by a second conveying roller pair 20 including a driving roller 21 and a driven roller 22 and a third conveying roller pair 30 including a driving roller 31 and a driven roller 32. You.
[0020]
The switchback unit 4 is provided with a fourth transport roller pair 40, and the cut recording medium 1 transported in the transport path A by the second transport roller pair 20 and the third transport roller pair 30 is provided. After being once received from the leading end, the direction is changed so that the sheet is conveyed from the rear end side to a conveying path B toward the fixing device 5 described later. Reference numeral 4a denotes a transfer path switching gate, which can be switched by a driving unit (not shown).
[0021]
A fifth conveyance roller pair 50 and a sixth conveyance roller pair 60 are further disposed on the conveyance path B between the fourth conveyance roller pair 40 and the fixing device 5, and each of the conveyance roller pairs 40, 50, By 60, the recording medium 1 in the transport path B that has been switched back is transported to the fixing device 5.
[0022]
The fixing device 5 is an endless belt that is stretched between a heating roller 5a having a heating element 5b such as a halogen lamp heater as a heat source therein and a driving roller 5c that is driven to rotate by a driving motor (not shown). And a pressure roller 5e which presses the fixing belt 5d with a predetermined pressure so as to sandwich the fixing belt 5d between the heating roller 5a and the fixing belt 5d. In this embodiment, the fixing belt 5d is disposed so as to face the recording surface 1a of the recording medium 1.
[0023]
The fixing belt 5d is formed by applying a curable silicone resin as a releasable layer to nickel electroforming, and is adjusted so that the peeling force satisfies 30 g / 5 cm or more. As a result, the recording medium 1 that has passed between the heating roller 5a and the pressure roller 5e is appropriately brought into close contact with the surface of the fixing belt 5d, and at the same time, is quickly peeled off on the driving roller 5c side, so that the fixing device 5 smoothly. Can be discharged.
[0024]
The surface roughness of nickel electroformed as the base material of the fixing belt 5d is preferably 0.1 μm or less, and the Young's modulus is preferably 50 kN / mm ² or more. A surface treatment layer containing various surface modifiers is provided on the surface of the nickel electroformed belt in order to improve the adhesiveness with the release layer. The thickness is preferably from 0.2 to 10 μm, more preferably a pencil hardness of HB or more and a swelling ratio of less than 5%. The release layer preferably has a surface contact angle of 100 to 120 degrees and a surface roughness of 0.2 μm or less.
[0025]
The recording medium 1 conveyed to the fixing device 5 is sandwiched between a fixing belt 5d wrapped around a heating roller 5a and a pressure roller 5e, and the thermoplastic resin particles contained in the layer structure of the recording medium 1 are removed. It is made transparent by melting and smoothing. At this time, the fixing temperature by heating of the heating roller 5a is preferably equal to or higher than the Tg (glass transition point) of the thermoplastic resin particles in order to appropriately make the thermoplastic resin particles transparent and obtain a good quality image print. . Further, the fixing temperature is preferably equal to or lower than the thermal deformation temperature of the support (which will be described in detail later) constituting the recording medium 1. If the temperature is higher than the thermal deformation temperature, the recording medium 1 is undesirably deformed such as warping or waving at the time of fixing. The temperature in the fixing device 5 is controlled based on the temperature detected by a temperature sensor (not shown) arranged near the heating roller 5a or the fixing belt 5d.
[0026]
The fixing device 5 is provided with a first removing unit 70 that comes into contact with a surface 5B of the fixing belt 5d opposite to the contact surface 5A with the recording medium 1 and removes the adhering matter attached to the surface 5B. ing. The first removing means 70 cleans the surface 5B opposite to the contact surface 5A with the recording medium 1 and removes the adhering matter, so that the unevenness of the nip between the heating roller 5e and the heating roller 5e caused by the adhering matter is removed. Thus, the fixing unevenness of the recording medium 1 can be eliminated, and the fixing device 5 can uniformly fix the recording medium 1.
[0027]
The first removing means 70 preferably contacts the fixing belt 5d at a constant speed with a surface 5B opposite to the contact surface 5A with the recording medium 1. By contacting the fixing belt 5d at a constant speed, there is no possibility that the fixing belt 5d will be rubbed and damaged, and since the fixing belt 5d is not rubbed, there is no substantial load on the driving thereof. This is effective in performing the fixing of No. 1 uniformly. Note that “constant speed” in the present specification means that the linear velocities of the contact surfaces are equal to each other.
[0028]
The first removing unit 70 shown in the present embodiment is configured to have the adhesive roller 71 rotatably abutting on the surface 5B in that the first removing unit 70 can easily contact the fixing belt 5d at a constant speed. . Although one is provided in the illustrated example, the number is arbitrary. Here, the adhesive roller 71 is configured as a driven roller that rotates with the driving of the fixing belt 5d by contacting the surface 5B of the fixing belt 5d. May be configured to rotate at the same speed as the fixing belt 5d by driving the driving motor.
[0029]
As shown in FIG. 2, the adhesive roller 71 is at least as long as the fixing belt 5d and has a length equal to or greater than the width of the fixing belt 5d so as to come into contact with the back surface of the fixing belt 5d, that is, the surface 5B opposite to the contact surface 5A with the recording medium 1. Are located in When the fixing belt 5d is driven to start fixing, the fixing belt 5d rotates at a constant speed in accordance with the driving of the fixing belt 5d, and adheres to the surface 5B with the adhesive force of the surface to remove it. to clean up.
[0030]
The adhesive roller 71 can be used with almost no problem as long as it has an adhesive surface. Examples of preferable surface materials include natural rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, silicone rubber, and fluorine. Rubber, urethane rubber, styrene / butadiene rubber, styrene / isoprene rubber, polyisoprene rubber, acrylic rubber, and the like. Among these, the surface is preferably made of silicone rubber or butyl rubber, from the viewpoint of having a high viscoelastic effect and capable of effectively removing deposits attached to the surface 5B of the fixing belt 5d.
[0031]
The adhesive roller 71 may have heat resistance, weather resistance, etc. in addition to adhesiveness. In view of this, it is preferable to use silicone rubber. Further, as the silicone rubber, a peroxide curing type, an addition type, a condensation type and the like can be mentioned, but an addition type silicone rubber is preferable from the viewpoint of moldability.
[0032]
In addition, the surface material of the adhesive roller 71 may contain additives such as carbon and iron oxide for the purpose of improving functions such as heat resistance and suppressing static electricity.
[0033]
Similarly, the surface hardness of the pressure-sensitive adhesive roller 71 is preferably 3 to 60 from the viewpoint that the viscoelastic effect is high and that the adhered matter adhered to the surface 5B of the fixing belt 5d can be effectively removed. The hardness here is a value obtained by a hardness test and a spring hardness test (A type) according to JIS-K6301-1975. If the hardness is less than 3, the adhesiveness is too high, which is not preferable because it causes troubles such as damaging the surface 5B and transferring the adhesive rubber itself. On the other hand, if the hardness is more than 60, the ability to remove deposits becomes low, and it becomes difficult to obtain the intended function, which is not preferable. A more preferred value of hardness is 10 to 40.
[0034]
Further, it is preferable that the surface of the adhesive roller 71 is physically roughened by polishing the surface for the purpose of adjusting the adhesive force, and the surface roughness is optionally adjusted. That is, if the surface is polished, the roller surface becomes uneven and has an appropriate adhesive strength, and it is less likely to cause a problem of damaging the surface 5B while maintaining the effect of removing the attached matter. Preferred for. As the polishing process, a process of polishing and shaping the roller surface with a rotating grindstone to obtain a uniform surface state is performed. By selecting the particle size and the rotation speed of the grindstone, the unevenness of the roller surface can be processed to an appropriate level.
[0035]
A secondary roller 72 is disposed on the surface of the adhesive roller 71 so as to be in contact therewith. The secondary roller 72 is constituted by an adhesive roller having a greater adhesive force than the adhesive roller 71, and removes the adhered matter removed from the surface 5B of the fixing belt 5d by the adhesive roller 71 and adhered to the surface of the adhesive roller 71. It functions as a cleaning roller that removes and cleans from the surface. As a result, the surface of the adhesive roller 71 can be kept clean at all times, and the effect of removing the adhered substance can be maintained for a long period of time. Therefore, such a secondary roller 72 is disposed in the first removing means 70. This is a preferred embodiment of the present invention.
[0036]
Although not shown, the secondary roller 72 may be contacted with a tertiary or higher roller having a stronger adhesive force to remove the adhering matter adhering to the secondary roller 72.
[0037]
In FIGS. 1 and 2, reference numeral 73 denotes a driven roller disposed so as to be in contact with the surface of the fixing belt 5d opposite to the adhesive roller 71, that is, the contact surface 5A of the fixing belt 5d with the recording medium 1. is there. By causing the driven roller 73 to abut against the adhesive roller 71 with the fixing belt 5d interposed therebetween, the adhesive roller 71 can be placed on the surface of the fixing belt 5d without substantially applying tension to the fixing belt 5d. 5B can be brought into contact with a predetermined pressing force, and the effect of removing the attached matter by the adhesive belt 71 can be further enhanced.
[0038]
The driven roller 73 may also be constituted by the same adhesive roller as the adhesive roller 71. In this case, the adhered substance adhered to the contact surface 5A of the fixing belt 5d with the recording medium 1 is simultaneously removed. Since this can be performed, it is not necessary to particularly provide a means for removing and cleaning the deposits on the contact surface 5A, which is preferable because the structure can be simplified. In particular, in the present embodiment, the contact surface 5A with the recording medium 1 is a surface that is in direct contact with the recording surface 1a of the recording medium 1. 5 is a preferred embodiment because the recording medium 1 can be fixed in an optimal state.
[0039]
Further, the fixing device 5 contacts the surface of a pressure roller 5e, which is disposed so as to oppose the contact surface 5A of the fixing belt 5d with the recording medium 1 with the recording medium 1 interposed therebetween, at a constant speed. It is also preferable to provide a second removing means 80 for removing the deposit attached to the surface.
[0040]
The second removing means 80 is composed of an adhesive roller 81 rotatably in contact with the surface of the pressure roller 5e, and is configured as a driven roller that rotates with the rotation of the pressure roller 5e. Of course, by connecting to a drive motor (not shown), it may be configured to be driven to rotate at the same speed as the pressure roller 5e.
[0041]
By providing the second removing means 80 on the surface of the member facing the recording medium 1 and the contact surface 5A of the fixing belt 5d with the recording medium 1 interposed therebetween, when the recording medium 1 is passed and pressurized, In addition, since the surface of the pressing surface can be made a clean and smooth surface with no deposits, there is no occurrence of unevenness in pressing and the like, and a uniform pressing force can be applied to the recording medium 1, and as a result, Uniform fixing can be performed over the entire surface of the recording medium 1.
[0042]
The same adhesive roller as the adhesive roller 71 can be used as the adhesive roller 81. Further, the cleaning roller 82 is a secondary roller which is a secondary roller that removes an adhering substance adhered to the surface of the adhesive roller 81 by contacting the surface of the adhesive roller 81 with a greater adhesive force than the adhesive roller 81, and further includes the cleaning roller 82. It is a matter of course that a tertiary or subsequent adhesive roller may be provided to abut the roller.
[0043]
The recording medium 1 on which the image is fixed in the fixing device 5 is discharged from the discharge port C to the outside of the apparatus by a discharge roller pair 90 including a driving roller 91 and a driven roller 92.
[0044]
In the ink jet recording apparatus described above, before the recording medium 1 is conveyed to the fixing device 5, the adhering matter adhering to the recording surface 1 a of the recording medium 1 is removed in advance. It is also preferable to arrange a third removing means for contacting the recording surface 1a of the recording medium 1 at a constant speed and removing the deposits attached to the recording surface 1a. Hereinafter, the third removing means will be described.
[0045]
The third removing unit is an upstream side of the fixing device 5 and can remove attached matter which comes into contact with the recording surface 1a of the recording surface 1a of the recording medium 1 after image recording at a constant speed. In this embodiment, the third removing unit is used in the present embodiment by using the pair of conveying rollers 40, 50, and 60 disposed on the upstream side of the fixing device 5 shown in FIG.
[0046]
As shown in FIG. 3, these transport roller pairs 40, 50, and 60 are respectively disposed between drive rollers 41, 51, and 61 driven by a drive motor M, and drive rollers 41, 51, and 61 in contact with the drive rollers. And the driven rollers 42, 52, and 62 for holding the recording medium 1 therebetween, and the driven rollers 42, 52, and 62 are formed of adhesive rollers.
[0047]
The driven rollers 42, 52, and 62 formed of an adhesive roller are formed to have a length at least equal to or greater than the width of the recording medium 1, and by sandwiching the recording medium 1 between the driving rollers 41, 51, and 61, The recording medium 1 is disposed so as to be in contact with the recording surface 1a. The recording medium 1 is conveyed toward the fixing device 5 by the rotation of the drive rollers 41, 51, 61, and rotates at a constant speed with respect to the recording surface 1a of the recording medium 1 and adheres to the recording surface 1a. The attached matter is adhered by the adhesive force of the surface and is removed from the recording surface 1a of the recording medium 1.
[0048]
As described above, the driven rollers 42, 52, and 62 are constituted by the adhesive rollers, and are used as the third removing means. And there is no worry that the recording surface 1a is rubbed and scratched. Further, in this embodiment, since the third removing means also serves as one of the pair of transport rollers, it is not necessary to provide the third removing means separately from the transporting means, thereby reducing the number of parts and the structure. Simplification can be achieved.
[0049]
As the driven rollers 42, 52, 62 formed of these adhesive rollers, the same adhesive roller as the adhesive roller 71 used in the first removing unit 70 can be used.
[0050]
Secondary rollers 43, 53, 63 are arranged on the driven rollers 42, 52, 62 on the side opposite to the contact surface with the driving rollers 41, 51, 61, respectively. It is in contact with the surface. These secondary rollers 43, 53, 63 are formed of adhesive rollers having a greater adhesive force than the driven rollers 42, 52, 62, and each of the driven rollers 42, including the adhesive roller from the recording surface 1 a of the recording medium 1, It functions as a cleaning roller that removes the adhered matter removed by the surfaces of the driven rollers 42, 52, 62 from the surfaces thereof and cleans them. As a result, the surfaces of the driven rollers 42, 52, and 62 can be kept clean at all times, and the effect of removing the adhered substances can be maintained for a long period of time. Is a more preferred embodiment.
[0051]
Although not shown, the secondary rollers 43, 53, and 63 are brought into contact with the third and subsequent rollers having a stronger adhesive force so as to remove the deposits attached to the secondary rollers 43, 53, and 63. Is also good.
[0052]
By providing the third removing means on the upstream side of the fixing device 5 as described above, the deposits such as dust and paper powder adhering to the recording surface 1a of the recording medium 1 conveyed to the fixing device 5 are removed. Therefore, the fixing device 5 does not apply heat and pressure in the state in which the attached matter is attached, and an image defect due to the attached matter already attached to the recording surface 1a of the recording medium 1 before fixing is generated. No problem arises.
[0053]
Here, the third removing means is constituted by three rollers of driven rollers 42, 52, and 62 made of an adhesive roller. However, the number of the third removing means is not particularly limited. In the case where the unit 3 is provided, at least one unit may be provided after the cutter unit 3 and upstream of the fixing device 5.
[0054]
Although not shown, in order to more effectively remove the adhering matter adhering to the recording surface of the recording medium 1, in addition to the adhesive roller in the third removing means, an upstream side of the fixing device 5 is provided. Alternatively, a cleaning brush or a cleaning sponge may be provided to abut on the recording surface 1a of the recording medium 1 so as not to damage the recording surface 1a and clean the surface.
[0055]
In the ink jet recording apparatus described above, the recording medium 1 is not limited to the one supplied from the illustrated roll paper, and may be a sheet-like sheet cut in advance to a prescribed size. In this case, the cutter unit 3 does not necessarily have to be provided.
[0056]
Next, an example of the recording medium 1 used in the ink jet recording apparatus according to the present invention will be described.
[0057]
As shown in FIG. 4, the recording medium 1 has an ink receiving layer 1B containing thermoplastic resin particles on a surface layer of a support 1A, and a coloring material and an ink solvent component are adjacent to the ink receiving layer 1B. It is configured to have at least a pigment ink solvent absorbing layer 1C having a void layer in which the ink solvent component is absorbed after being separated on the surface of the receiving layer 1B.
[0058]
As the support 1A, a support conventionally used as an ink jet recording medium can be used. For example, in addition to a paper support such as plain paper, art paper, coated paper, and cast coated paper, a plastic support can be used. A body support, a paper support coated on both sides with a polyolefin, and a composite support obtained by laminating these can be used.
[0059]
Examples of the thermoplastic resin particles contained in the ink receiving layer 1B include, for example, polycarbonate, polyacrylonitrile, polystyrene, polyacrylic acid, polymethacrylic acid, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyamide, and poly. Examples include ethers, copolymers thereof, and salts thereof. The thermoplastic resin particles are appropriately selected in consideration of ink receptivity, glossiness of an image after fixing by heating and pressurizing, image fastness, and releasability.
[0060]
Regarding the ink receptivity, when the particle size of the thermoplastic resin particles is less than 0.05 μm, the separation of the pigment particles from the pigment solvent in the pigment ink and the ink solvent becomes slow, resulting in a decrease in the ink absorption speed. On the other hand, if it exceeds 10 μm, it is not preferable from the viewpoints of adhesiveness to the pigment ink solvent absorbing layer 1C adjacent to the ink receiving layer 1B when coating on the support and the film strength of the recording medium after coating and drying. For this purpose, the preferred thermoplastic resin particle diameter is preferably 0.05 to 10 μm, and more preferably 0.1 to 5 μm.
[0061]
The thermoplastic resin particles forming the outermost layer exist in a dispersed state in a solvent such as water before coating and drying. In the case of a single thermoplastic resin particle having no variation in the dispersed particle size, the particles are packed in the closest hexagonal shape by drying after coating to form a single particle layer, and the porosity at that time is about 26%. It is. However, thermoplastic resin particles are usually polydisperse, and the porosity changes depending on the state of aggregation of the thermoplastic resin particles. The diameter of the formed void depends on the particle diameter of the thermoplastic resin particles.
[0062]
The coating thickness on the support 1A is preferably 0.1 to 10 μm, more preferably 0.5 to 7 μm.
[0063]
As a criterion for selecting the thermoplastic resin particles, a glass transition point (Tg) can be mentioned. When Tg is lower than the coating and drying temperature, for example, the coating and drying temperature during the production of the recording medium is already higher than Tg, and the voids due to the thermoplastic fine particles through which the ink solvent permeates disappear. If the Tg is higher than the temperature at which the support 1A is denatured by heat, a fixing operation at a high temperature is required to form a melted film after inkjet recording with the pigment ink, so that the load on the apparatus and the heat of the support 1A are increased. Stability is a problem. The preferable Tg of the thermoplastic resin particles is 50 to 150 ° C., and the temperature control in the fixing device 5 described above sets this Tg as the target temperature.
[0064]
After image formation, it is necessary to suppress deterioration of image quality of a recorded image due to its storage over time as much as possible. In the case of using pigment ink, there is no need to worry about density reduction and discoloration in a relatively short period of time unlike dye ink, but it is necessary to prevent unprinted portions from being yellowed (decomposed) by UV light. It is necessary to select thermoplastic resin particles from the above.
[0065]
The pigment ink solvent absorbing layer 1C adjacent to the outermost ink receiving layer 1B needs to have the ability to absorb the pigment ink solvent. This is exhibited by being contained in the solvent absorption layer.
[0066]
Examples of the inorganic fine particles used for the above purpose include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, and zinc sulfide. , Zinc carbonate, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, magnesium hydroxide, etc. And white inorganic pigments.
[0067]
The average particle size of the inorganic fine particles is determined by observing the fine particles themselves or the fine particles that have appeared on the cross section or surface of the void-type pigment ink solvent absorption layer with an electron microscope, calculating the average particle size of 100 arbitrary particles, and calculating the simple average value. (Average number). Here, the particle diameter of each fine particle is represented by a diameter assuming a circle equal to the projected area.
[0068]
From the viewpoints that a high-density image is formed, a clear image can be recorded, and that it can be manufactured at a low cost, the inorganic solid fine particles include fine particle silica, colloidal silica, and alumina or alumina water synthesized by a gas phase method. It is preferable to use inorganic solid fine particles selected from the sum. Alumina or alumina hydrate may be crystalline or non-crystalline, and may have any shape such as irregular particles, spherical particles, and acicular particles. At present, particulate silica synthesized by such a gas phase method is commercially available, and various types of commercially available particulate silica include Aerosil manufactured by Nippon Aerosil Co., Ltd.
[0069]
The average particle size of the inorganic fine particles is not particularly limited, but is preferably 100 nm or less, and the most preferable average particle size for forming the void layer differs depending on the compound. For example, in the case of the above-mentioned fumed silica, it is most preferable that the average particle diameter of the primary particles of the inorganic fine particles dispersed in the state of the primary particles (the particle diameter in the dispersion state before coating) is 4 to 20 nm. It can be preferably used.
[0070]
As the pigment ink solvent absorbing layer 1C, in addition to using the above inorganic fine particles, for example, various hydrophilic resins and silica described in JP-A-59-148585, JP-A-55-51583, JP-A-58-72495, and the like can be used. And a urethane resin emulsion containing an alkylene oxide or a polycarbonate described in JP-A-9-150574 and JP-A-10-181189.
[0071]
Further, in addition to forming the pigment ink solvent absorbing layer using the inorganic fine particles, a coating using a polyurethane resin emulsion, a water-soluble epoxy compound and / or acetoacetylated polyvinyl alcohol, and an epichlorohydrin polyamide resin in combination. The pigment ink solvent absorbing layer 1C may be formed using a working liquid.
[0072]
In this case, the polyurethane resin emulsion is preferably a polyurethane resin emulsion having a polycarbonate chain, a polycarbonate chain and a polyester chain and having a particle size of 3.0 μm, and the polyurethane resin of the polyurethane resin emulsion is a polyol having a polycarbonate polyol, a polycarbonate polyol and a polyester polyol. And a polyurethane resin obtained by reacting the compound with an aliphatic isocyanate compound, further comprising a sulfonic acid group in the molecule, and further comprising an epichlorohydrin polyamide resin and a water-soluble epoxy compound and / or acetoacetylated vinyl alcohol. preferable.
[0073]
It is presumed that weak aggregation of cations and anions is formed in the pigment ink solvent absorbing layer 1C using the above-described polyurethane resin, and accordingly, voids having the pigment ink solvent absorbing ability are formed, so that an image can be formed.
[0074]
In the ink-receiving layer 1B and a pigment ink solvent absorbing layer 1C of the recording medium 1, the total amount of the void (void volume) is preferably a recording sheet 1 m ² per 20ml or more. When the void volume is less than 20 ml / m ² , if the ink amount at the time of printing is 1 ml / m ² or less, the ink absorbency is good, but if the ink amount exceeds 40 ml / m ² , the ink is completely absorbed. Problems such as deterioration of image quality and slow drying property are likely to occur.
[0075]
Although the upper limit of the void volume is not particularly limited, it is necessary that the thickness of the void-type ink absorbing layer is usually 50 μm or less in order not to deteriorate the physical properties of the coating such as cracks. Is difficult to be 40 ml / m ² or more. The void volume is described in J. TAPPI paper pulp test method No. When measured by the liquid absorption test method (Bristow method) of 51-87 paper or paperboard, it is represented by the liquid transfer amount (ml / m ² ) at an absorption time of 2 seconds. In the above measurement method, pure water (ion-exchanged water) is used for the measurement, but a water-soluble dye of less than 2% may be contained in order to easily determine the measurement area.
[0076]
At the time of applying the recording medium, a thickener may be used to improve applicability. As a coating method, in addition to a bar coater, a roll coater, an applicator, a spinner, and the like, when two or more layers are simultaneously coated from the viewpoint of increasing production efficiency, extrusion coating and curtain coating are particularly effective.
[0077]
Examples of the silicon emulsion or water-soluble silicon compound preferably contained in the ink receiving layer 1B include, for example, a dimethylsiloxane compound having a siloxane functional group of methyl and a general release agent, and a vinyl group or hydrogen as a substituent of the compound. Compounds in which an atom, a mercapto group, a methacryl group, an acryl group, an amino group, a phenyl group, etc. are introduced. Further, the content is preferably less than 1% by mass ratio to the thermoplastic resin particles 100. When the addition amount is 1% or more, the releasability is improved, but color unevenness presumed to be caused by non-uniformity of fixing due to heating and pressurization occurs, which is not preferable.
[0078]
The ink used for the recording surface 1a of the recording medium 1 is roughly classified into a dye ink and a pigment ink. In the present invention, the use of the pigment ink can provide a high quality image. Further, it is preferable in that the storability of the image is good. As the pigment ink, conventionally known organic and inorganic pigments can be used. For example, polycyclic pigments such as azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments, phthalocyanine pigments, perylene pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthaloni pigments Dye lakes such as basic dye lakes and acid dye lakes; organic pigments such as nitro pigments, nitroso pigments, aniline black and daylight fluorescent pigments; and inorganic pigments such as carbon black.
[0079]
Specific organic pigments are exemplified below.
[0080]
Pigments for magenta or red include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139, C.I. I. Pigment Red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 and the like.
[0081]
Examples of orange or yellow pigments include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 138 and the like.
[0082]
Examples of green or cyan pigments include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.
[0083]
【The invention's effect】
According to the present invention, in an ink jet recording apparatus having a fixing belt as a fixing unit, high-quality images can be obtained by performing uniform fixing by eliminating uneven fixing of a recording medium due to an adhered substance adhered to the back side of the fixing belt. You can get a print.
[Brief description of the drawings]
FIG. 1 is a side view illustrating a schematic configuration of an ink jet recording apparatus. FIG. 2 is a perspective view illustrating a schematic configuration of a fixing device. FIG. 3 is a perspective view illustrating a configuration example of a third removing unit. Sectional view showing the laminated structure [Description of reference numerals]
1: recording medium 1a: recording surface 2: recording unit 2a: recording head 3: cutter unit 4: switchback unit 5: fixing device 5A: contact surface with the recording surface of the recording medium 5B: contact with the recording surface of the recording medium Surface 5a opposite to surface 5a: heating roller 5b: heating element 5c: driving roller 5d: fixing belt 5e: pressing roller 10: first conveying roller pair 11: driving roller 12: driven roller 20: second conveying roller pair 21 : Drive roller 22: driven roller 30: third transport roller pair 31: drive roller 32: driven roller 40: fourth transport roller pair 41: drive roller 42: driven roller (third removing means; adhesive roller)
43: Secondary roller (cleaning roller)
50: fifth transport roller pair 51: drive roller 52: driven roller (third removing means; adhesive roller)
53: Secondary roller (cleaning roller)
60: Sixth transport roller pair 61: Drive roller 62: Follower roller (third removing means; adhesive roller)
63: Secondary roller (cleaning roller)
70: first removing means 71: adhesive roller 72: secondary roller (cleaning roller)
73: driven roller 80: second removing means 81: adhesive roller 82: secondary roller (cleaning roller)
90: discharge roller pair 91: drive roller 92: driven roller

Claims (6)

In an ink jet recording apparatus having a fixing unit for performing recording on a recording medium having thermoplastic resin particles, and fixing the thermoplastic resin particles of the recording medium by heating and pressing the recording medium after recording, the fixing unit A heating roller and a pressure roller, a fixing belt that fixes the recording medium by sandwiching the recording medium between the heating roller and the pressure roller, and a surface of the fixing belt opposite to a contact surface with the recording medium. An ink jet recording apparatus, comprising: a removing unit that removes an adhering substance adhering to the surface by contacting the surface. 2. The ink jet recording apparatus according to claim 1, wherein the removing unit contacts the fixing belt at a constant speed on a surface of the fixing belt opposite to a contact surface with a recording medium. The ink jet recording apparatus according to claim 1, wherein the removing unit is an adhesive roller. The ink jet recording apparatus according to claim 3, wherein the adhesive roller has a surface made of silicon rubber or butyl rubber having viscoelasticity. The ink jet recording apparatus according to claim 3, wherein the adhesive roller has a surface hardness of 3 to 60. 6. 6. The ink jet recording apparatus according to claim 3, further comprising a cleaning roller for contacting the adhesive roller and cleaning a surface of the adhesive roller.

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