JP4356364B2 - Image recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus that performs image recording by an inkjet method.
[0002]
[Prior art]
In general, an inkjet image recording apparatus has been known as an image recording apparatus that can respond flexibly to the demand for a small quantity and a wide variety of products. An inkjet image recording apparatus records an image on a recording medium by ejecting ink from nozzles provided on the surface of the recording head facing the recording medium and landing and fixing on the recording medium. Unlike the image recording means using the gravure printing method or flexographic printing method, a plate making process is not required, so that it can easily and quickly respond to a small amount of demand. In addition, there is an advantage that color image recording can be easily performed by using multi-color ink with less noise.
[0003]
An ink jet image recording apparatus can perform high-definition image recording on a wide variety of recording media, and particularly uses a recording medium having an ink receiving layer containing thermoplastic resin particles on the recording surface side. In such a case, a glossy photographic image recording image can be obtained by melting and smoothing the thermoplastic resin particles after image recording.
[0004]
However, in order to perform high-definition image recording using a recording medium containing such thermoplastic resin particles, a process for producing a beautiful gloss is required, and the surface of the recording medium is also used for image recording. Various considerations are necessary so as not to hurt.
[0005]
That is, first, in order to melt the thermoplastic resin and smooth the surface of the recording medium, it is necessary to heat and press the recording medium after ejecting and fixing the ink on the recording medium. Further, it is known to provide a heating and pressing unit including a heating belt or a heating roller and a pressure belt or a heating roller (see, for example, Patent Document 1).
[0006]
In addition, paper dust or dust generated when the recording medium is cut easily adheres to the surface of such a heating roller or pressure roller. The image quality of the recorded image may be reduced by reattaching to the recording surface. Therefore, in order to perform high-quality image formation, conventionally, a cleaning roller that adsorbs and removes dust adhering to the surfaces of the heating roller and the pressure roller has been provided (see, for example, Patent Document 2). ).
[0007]
Further, when the recording medium is heated and pressed using, for example, a heating roller and a pressure roller, in order to finish a recorded image with high glossiness and high quality, the heating roller and the pressure roller It is necessary to prevent the deflection of the roller caused by the recording medium passing between them so that sufficient pressure is evenly applied to the recording medium. For this reason, a backup roller that presses and urges the heating roller and pressure roller from the outside is conventionally provided. In order to increase the pressing force evenly, the backup roller comes into contact with the peripheral surface of the backup roller. Providing a plurality of support members that press the roller has also been proposed (see, for example, Patent Document 3).
[0008]
In addition, if the recording medium is wrinkled when the recording medium is heated and pressed, the image quality of the recorded image is deteriorated. Therefore, the shape of the heating roller and the pressure roller is set in the axial direction to prevent wrinkles. It has been proposed that the central portion of the roller where the surface pressure is reduced is pressed by a backup roller after making the reverse crown shape formed so that the diameter of the central portion is smaller than the diameter of both end portions (for example, Patent Document 4). reference).
[0009]
[Patent Document 1]
JP 2002-187341 A
[Patent Document 2]
JP-A-8-248802
[Patent Document 3]
Japanese Patent Laid-Open No. 9-68883
[Patent Document 4]
JP-A-7-225523
[0010]
[Problems to be solved by the invention]
However, a releasable layer made of resin or the like is formed on the peripheral surface of the heating roller. Since this releasable layer is in direct contact with the surface of the recording medium, the state of the releasable layer is the recording medium. Affects the gloss of the recorded image. That is, when the surface of the release layer of the heating roller has irregularities, the gloss of the surface of the image formed on the recording medium is increased by pressing the release layer against the surface of the recording medium during heating and pressing. I can't get enough. Therefore, it is conceivable that the arithmetic average roughness (Ra) of the surface of the heating roller is regulated to a certain value or less. However, since the release layer formed on the surface of the heating roller is easily damaged, the pressure applied to the heating roller is pressed. Even when the arithmetic average roughness of the roller peripheral surface is rough, when the heating roller is pressed by the pressure roller, the release layer on the surface of the heating roller is damaged, resulting in insufficient gloss of the recorded image. As a result, the image quality is degraded. Furthermore, even when the arithmetic average roughness of the peripheral surface of the backup roller is rough, the release layer on the surface of the heating roller and the surface of the pressure roller may be damaged when the backup roller presses the heating roller and the pressure roller. As a result, there is a problem that it is impossible to form a glossy high-quality image of the recorded image. This can also occur when the surface pressure that presses the backup roller against the heating roller and the pressure roller is high regardless of the arithmetic average roughness of the backup roller.
[0011]
In addition, in order to be able to perform continuous high-quality image recording, it is necessary to remove dust adhering to the rollers of the heating roller and the pressure roller and perform appropriate cleaning. In the case of providing, the number of rollers provided in contact with the heating roller and the pressure roller increases, resulting in complication and enlargement of the apparatus. Further, since the cleaning roller is generally expensive, there is a problem that the cost of the apparatus is increased.
[0012]
Furthermore, when the support member is provided so as to abut on the peripheral surface of the backup roller in order to urge the pressing force of the backup roller, the support member may damage the surface of the backup roller. When such a scratch is made on the peripheral surface of the backup roller, the surface of the heating roller and the pressure roller is also damaged when the heating roller and the pressure roller are pressed by the backup roller. There is a problem that the image cannot be sufficiently obtained and high-quality image formation cannot be performed.
[0013]
In addition, when the reverse crown-shaped heating roller and pressure roller are pressed by the backup roller, the length of the backup roller is shorter than the length of the heating roller or pressure roller. If the stress is concentrated, the surfaces of the heating roller and the pressure roller may be damaged. In this case, if the recording medium is heated and pressed by a roller having a scratched surface, the surface gloss of the image formed on the recording medium cannot be sufficiently obtained, and the image quality of the recorded image is deteriorated. There's a problem.
[0014]
Therefore, the present invention has been made to solve the above-described problems, and can form a glossy high-definition image when performing image recording on a recording medium containing a thermoplastic resin by an inkjet method. An object of the present invention is to provide an image recording apparatus.
[0015]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, the invention according to claim 1 is a recording head for ejecting ink onto a recording medium.And a heating roller that is arranged on the downstream side of the recording medium conveyance path from the recording head and that heats the recording medium, and a pressure roller that is arranged at a position facing the heating roller, The arithmetic average roughness (Ra) of the surfaces of the heating roller and the pressure roller are both 0.5 μm or less,In an image recording apparatus for recording an image while conveying the recording medium in a certain direction,
  A backup roller that presses and urges the heating roller and the pressure roller;
  The backup roller has an arithmetic average roughness (Ra) of the surface of 0.5 μm or less.It is characterized by that.
[0016]
  In the invention according to claim 1 having such a configuration, the recording medium is pressurized by a pressure roller having a small arithmetic average roughness (Ra) on the surface, and therefore the recording medium is heated and pressed. When the thermoplastic resin particles contained in the ink receiving layer are melted, the surface thereof can be smoothed.
  Further, since the arithmetic average roughness of the backup roller surface is small, it is possible to prevent the surfaces of the heating roller and the pressure roller from being damaged by the pressure of the backup roller when the recording medium is pressed.
[0019]
  further,Claim 2The invention described inClaim 1The surface pressure between the backup roller and the heating roller and the surface pressure between the backup roller and the pressure roller are between the heating roller and the pressure roller. It is characterized by being below the surface pressure.
[0020]
  in this way,Claim 2Since the surface pressure between the backup roller, the heating roller and the pressure roller is low, the separation formed on the surface of the heating roller when the heating roller and the pressure roller are pressed by the backup roller. It is possible to prevent the mold layer from being worn or damaged.
[0021]
  Also,Claim 3The invention described in claim 1Or claim 2In the image recording apparatus described above, the backup roller also serves as a cleaning roller for cleaning the surfaces of the heating roller and the pressure roller.
[0022]
  in this way,Claim 3Since the surface of the heating roller and the pressure roller is cleaned by the backup roller, it is not necessary to provide a separate cleaning roller.
[0023]
  further,Claim 4The invention according to claim 1 is fromClaim 3In the image recording apparatus according to any one of the above, the shape of the backup roller follows the shape of the heating roller and the pressure roller when the shape of the heating roller and the pressure roller is an inverted crown shape. It is characterized by having a regular crown shape.
[0024]
  Claim 4In the invention described in the above, the entire recording medium can be uniformly heated and pressed by forming the backup roller in a regular crown shape so as to follow the shapes of the peripheral surfaces of the heating roller and the pressure roller. In addition, stress does not concentrate on the end of the backup roller, and even when the backup roller is formed to have a shorter length than the heating roller and the pressure roller, the surface of the heating roller and the pressure roller is pressed without being damaged. be able to.
[0025]
  further,Claim 5The invention according to claim 1 is fromClaim 4In the image recording apparatus according to any one of the above, the backup roller has a regular crown shape.
[0026]
  Claim 5In the invention described in the above, the back-up roller is formed into a regular crown shape, so that stress is not concentrated on the end of the back-up roller, and the back-up roller is formed to have a shorter length than the heating roller and the pressure roller. Even in this case, the surface of the heating roller and the pressure roller can be pressed without being damaged.
[0027]
  Also,Claim 6The invention according to claim 1 is fromClaim 5The image recording apparatus according to any one of the above, wherein the recording medium is a recording medium having a layer containing thermoplastic resin particles on the recording surface side.
[0028]
  Claim 6According to the invention described in the above, a high-definition image can be recorded when image recording is performed using a recording medium that melts the thermoplastic resin layer on the surface by heating and pressurizing to give gloss to the recorded image. It is like that.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, as shown in FIG. 1, in the present embodiment, a paper feed roll 2 around which a long recording medium P having a predetermined width is wound is rotatably arranged at one end inside the image recording apparatus 1. It is installed. The paper feed roll 2 is driven to rotate by a drive mechanism (not shown), and the recording medium P is sent out in a predetermined transport direction X as the paper feed roll 2 rotates.
[0030]
A pair of first transport rollers 3 a and 3 b that sandwich the recording medium P from the recording surface side and the non-recording surface side are provided above the paper feed roll 2. The recording medium P sent out from the paper supply roll is transported along a predetermined transport direction X while being supported by the first transport rollers 3a and 3b.
[0031]
A recording unit 4 is located in the downstream of the first conveying rollers 3a and 3b in the conveying direction X and substantially at the center of the upper surface of the image recording apparatus 1. It is arranged substantially horizontally along the upper surface of the device 1.
[0032]
Further, above the platen 5, recording heads 6, 6... Mounted on a carriage (not shown) are provided, and rod-shaped guides provided to extend in a direction orthogonal to the conveyance direction X of the recording medium P. It reciprocates along a rail (not shown).
[0033]
The recording heads 6, 6... Are provided for each color (for example, black (K), cyan (C), magenta (M), yellow (Y)) used in the present embodiment. Necessary ink is ejected onto the recording surface.
[0034]
On the downstream side of the platen 5 in the transport direction X, cutters 7a and 7b having lengths substantially equal to the width of the recording medium P are provided so as to extend in a direction perpendicular to the transport direction X. The cutters 7a and 7b are provided on both the recording surface side and the non-recording surface side of the recording medium P so as to face each other, and cut the recording medium P on which an image is recorded into a predetermined length. It has become. Among these, the cutter 7a provided on the recording surface side of the recording medium P can be moved up and down by a drive mechanism (not shown), and after the recording medium P that has finished image recording passes between the cutters 7a and 7b, the recording is performed. When the cutter 7a provided on the recording surface side of the medium P is lowered, the recording medium P can be cut into a predetermined length. The structure of the cutters 7a and 7b is not limited to this. For example, the cutters 7a and 7b include a fixed blade fixed at a predetermined position on the non-recording surface side of the recording medium P, and can be moved to the recording surface side of the recording medium P by a driving mechanism. You may make it provide the disk-shaped rotary cutter provided in. In this case, after the recording medium P that has finished image recording passes between the cutters, the rotary cutter moves on the recording medium P while rotating to cut the recording medium P into a predetermined length.
[0035]
A pair of second transport rollers 8a that transport the cut recording medium P along the transport direction X while sandwiching the cut recording medium P from the recording surface side and the non-recording surface side downstream of the cutters 7a and 7b. 8b is provided. Further, a switching unit 9 for switching the direction of conveyance of the recording medium P is provided on the downstream side in the conveyance direction X with respect to the second conveyance rollers 8a and 8b.
[0036]
A conveyance path from the paper feed roller 2 to the switching unit 9 is a first conveyance path 26, and the first conveyance path 26 is substantially directed downward from the image recording apparatus 1 with the second conveyance rollers 8 a and 8 b as fulcrums. It is bent at a right angle. The switching unit 9 is located at the lower end of the first transport path 26 and includes a pair of switching rollers 11a and 11b that are rotationally driven by a driving mechanism (not shown). The rotation direction of the switching rollers 11a and 11b can be switched as appropriate, and once the recording medium P is sent out from the lower end of the first transport path 26, the transport direction of the recording medium P is switched to the reverse direction and again in the transport path. To be drawn into. Of the switching rollers 11a and 11b, the switching roller 11b located on the recording surface side of the recording medium P has a surface covered with an adhesive material, and removes paper dust, dust, and the like attached to the surface of the recording medium P. It is like that. Further, a cleaning roller 12 having a length dimension substantially equal to that of the switching roller 11b is provided on the side surface of the switching roller 11b so as to contact the peripheral surface of the switching roller 11b. The cleaning roller 12 is made of a material having higher adhesiveness than the switching roller 11b, and adsorbs and removes paper dust and the like adhering to the switching roller 11b.
[0037]
The lower end portion of the first transport path 26 is branched to the second transport path 27, and the switching unit 9 is formed at this branch portion so that the transport path of the recording medium P is routed from the first transport path 26. A switching lever 10 for switching to the second transport path 27 is provided. The switching lever 10 is appropriately rotated by a driving mechanism (not shown), and the conveyance path of the recording medium P can be switched by this rotating operation.
[0038]
A pair of third transport rollers 13a and 13b that sandwich the recording medium P from the recording surface side and the non-recording surface side on the second transport path 27 and downstream of the switching rollers 11a and 11b in the transport direction X. Is arranged. Among these, the surface of the third conveying roller 13b located on the recording surface side of the recording medium P is covered with an adhesive material so as to remove paper dust and dust adhering to the surface of the recording medium P. It has become. On the side surface of the third conveyance roller 13b located on the recording surface side of the recording medium P among the third conveyance rollers 13a and 13b, a cleaning roller 14 having a length dimension substantially equal to that of the third conveyance roller 13b is provided. It is provided so as to contact the peripheral surface of 13b. The cleaning roller 14 is made of a material having higher adhesiveness than the third transport roller 13b, and adsorbs and removes paper dust and the like adhering to the third transport roller 13b.
[0039]
A fixing unit 15 that heats and pressurizes the recording medium P is provided downstream of the third transport rollers 13a and 13b in the transport direction X. As shown in FIG. 2, the fixing unit 15 includes a heating roller 16 having a length slightly longer than the width of the recording medium P, and a pressure roller 20 that contacts and presses the heating roller 16. ing. The heating roller 16 abuts on the recording medium P from the recording surface side for heating, and a heater 17 is provided inside the cylindrical roller body so as to extend along the axial direction. As the heater 17 used for the heating roller 16, for example, a halogen heater or a coil heater can be applied. The heating roller 16 is supported by a shaft 19 protruding from both ends, and is rotatable by a driving mechanism (not shown). Further, the heating roller 16 is formed of a material having high thermal conductivity such as a metal so that the recording medium P can be efficiently heated. The release layer 18 is covered. As described above, since the surface of the heating roller 16 is covered with the releasable layer 18, the recording medium P is also heated when the recording medium P is heated and pressurized to melt and smooth the thermoplastic resin particles. Can be easily peeled off. Note that the arithmetic average roughness (Ra) of the surface of the releasable layer 18 of the heating roller 16 is formed to be 0.5 μm or less. Since the releasable layer 18 of the heating roller 16 directly contacts the surface of the recording medium P when the recording medium P is heated and pressed, the recording is performed when the arithmetic average roughness of the surface of the releasable layer 18 is rough. This is because irregularities are generated on the surface of the medium P, and glossy and high-quality image formation cannot be performed.
[0040]
On the other hand, the pressure roller 20 has substantially the same length as the heating roller 16 and is provided on the non-recording surface side of the recording medium P so as to face the heating roller 16. The pressure roller 20 is supported by a shaft 21 protruding from both ends, and is rotatable by a drive mechanism (not shown). The pressure roller 20 is formed of an elastic material such as rubber so that the release layer 18 such as a resin covering the surface of the heating roller 16 is not damaged when the recording medium P is heated and pressurized. Therefore, the arithmetic average roughness of the surface of the pressure roller 20 is formed to be 0.5 μm or less.
[0041]
In the vicinity of each of the heating roller 16 and the pressure roller 20, the recording medium P is sandwiched between the heating roller 16 and the pressure roller 20 and biased from the side surface in order to secure a predetermined pressure when performing the heating and pressing. Backup rollers 22a and 22b are provided so as to abut against the peripheral surfaces of the heating roller 16 and the pressure roller 20, respectively. The backup rollers 22a and 22b are supported by shafts 23a and 23b protruding from both ends, and are rotatable by a driving mechanism (not shown). The backup rollers 22a and 22b are made of a material having elasticity such as rubber, and when the recording medium P is heated and pressed, the release layer 18 such as a resin covering the surface of the heating roller 16 and the surface of the pressing roller 20 are used. In order not to damage the surface, the arithmetic average roughness of the surface is 0.5 μm or less. Similarly, in order to protect the surfaces of the heating roller 16 and the pressure roller 20, the surface pressure of the backup rollers 22 a and 22 b when pressing the heating roller 16 and the pressure roller 20 is the same as that of the heating roller 16 and the pressure roller 20. Therefore, a predetermined surface pressure can be obtained by lowering the hardness of a material such as rubber forming the backup rollers 22a and 22b.
[0042]
A discharge port 25 for discharging the recording medium P is provided downstream of the fixing unit 15 in the transport direction X and at the end of the second transport path 27, and upstream of the transport direction X from the discharge port 25. Are provided with a pair of fourth transport rollers 24 a and 24 b for guiding the recording medium P to the discharge port 25.
[0043]
Here, in the recording medium P used in the present embodiment, an ink receiving layer containing thermoplastic resin particles is formed on the recording surface side, and a pigment ink solvent absorbing layer is formed below the ink receiving layer. Has been. The thermoplastic resin particles include, for example, polyacrylic ester, polycarbonate, polyacrylonitrile, polystyrene, polybutadiene, polyacrylic acid, polymethacrylic acid, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyamide, polyether, and the like. Among them, polyacrylic ester copolymer, styrene-acrylic acid ester copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylic acid ester copolymer, ethylene-vinyl acetate copolymer Polymers, ethylene-acrylic acid ester copolymers, and SBR latex are preferred. The recording medium P containing these thermoplastic resin particles is heated and pressed to melt and smooth the thermoplastic resin particles contained in the ink receiving layer, thereby forming a photo-quality image having a vitreous gloss. Make it possible.
[0044]
One of the first transport rollers 3a and 3b, the second transport rollers 8a and 8b, the third transport rollers 13a and 13b, and the fourth transport rollers 24a and 24b provided as a pair is rotated by a drive mechanism (not shown). The other is driven to rotate.
[0045]
Next, the operation of this embodiment will be described.
When the image recording operation is started, the recording medium P is sent out from the paper feed roll 2, guided by the first transport rollers 3 a and 3 b, and transported in the transport direction X along the first transport path 26. When the recording medium P is transported to a predetermined position on the platen 5, the carriage reciprocates along the guide rail and the required ink is ejected from the recording heads 6, 6... Based on predetermined image data. An image is recorded on the recording surface. When the portion where the image recording has been completed has passed between the cutters 7a and 7b, the cutter 7a provided on the recording surface side of the recording medium P descends, whereby the cutters provided above and below the recording medium P are sandwiched. 7a and 7b are in sliding contact with each other, and the image-recorded portion is cut from the long recording medium P.
[0046]
The cut recording medium P is guided to the second transport rollers 8a and 8b, transported along the first transport path 26, and is temporarily sent out of the first transport path 26 from the lower end portion of the first transport path 26. . Thereafter, the direction of the switching lever 10 is changed so that the front end of the switching lever 10 blocks the first transport path 26, and the switching rollers 11a and 11b rotate in the reverse direction. As a result, the recording medium P is drawn into the second transport path 27 and transported in the transport direction X along the second transport path 21 while being guided by the third transport rollers 13a and 13b. At that time, the cleaning rollers 12 and 14 in contact with the switching roller 11b and the third conveying roller 13b provided on the recording surface side of the recording medium P rotate with the rotation of the switching roller 11b and the conveying roller 13b, and recording is performed. Dirt such as paper dust adhering to the switching roller 11b and the conveying roller 13b is adsorbed and removed so that paper dust or ink does not adhere to the medium P again.
[0047]
When the recording medium P is conveyed to the fixing unit 15, the recording medium P passes between the heating roller 16 heated by the heater 17 and the pressure roller 20 that presses the heating roller 16, thereby heating the recording medium P. Pressurization is performed. At this time, the back-up rollers 22a and 22b press the heating roller 16 and the pressure roller 20 from the side surfaces to apply a pressing force. As a result, the thermoplastic resin particles contained in the ink receiving layer formed on the recording surface of the recording medium P are melted by being heated and smoothed by being pressed, whereby a glossy photo-quality image is obtained. It is formed.
[0048]
The recording medium P that has been heated and pressurized by the fixing unit 15 is guided by the fourth transport rollers 24 a and 24 b and discharged from the discharge port 25.
[0049]
In the present embodiment, the heating roller 16 and the pressure roller 20 are not provided with a cleaning roller. However, the cleaning roller is provided so as to be in contact with one or both peripheral surfaces of the heating roller 16 and the pressure roller 20. Then, the heating roller 16 and the pressure roller 20 may be cleaned. Further, the backup rollers 22a and 22b can also serve as a cleaning roller by making the material such as rubber forming the backup rollers 22a and 22b have a high viscosity. In this case, the backup rollers 22a and 22b are formed to have substantially the same length as the heating roller 16 and the pressure roller 20 so that the entire heating roller 16 and the pressure roller 20 can be cleaned. Is done.
[0050]
In the present embodiment, the image recording apparatus 1 transports the recording medium P in the transport direction X, and the recording heads 6, 6... Mounted on the carriage in a direction orthogonal to the transport direction X of the recording medium P. The image recording apparatus 1 of the serial print system that forms an image by ejecting ink from the recording heads 6, 6... While reciprocating is used. However, the image recording apparatus 1 is not limited to this system. A line print type image recording apparatus may be used in which ink is ejected from a recording head fixed to the main body of the recording apparatus and the recording medium P is conveyed to form an image.
[0051]
In the present embodiment, the recording medium P is a long recording medium P having a predetermined width wound around the paper feed roll 2. However, the shape of the recording medium P is not limited to this, and a predetermined recording medium P is used. The sheet-like recording medium P having a length may be sequentially taken out.
[0052]
In the present embodiment, the fixing unit 15 is composed of two types of roller pairs, that is, the heating roller 16 having the heater 17 and the pressure roller 20 formed of silicon rubber or the like. If it has a mechanism which can pressurize, it will not be restricted to this. For example, as shown in FIG. 3, a heating belt 31 stretched between a heating roller 28 provided with a heater 29 for heat generation instead of the heating roller 16 and the pressure roller 20 and a heating belt support roller 30; The recording medium P is heated and heated by passing the recording medium P between the pressing belt 32 provided between the pressing roller 32 and the pressing belt support roller 33. Pressure may be applied. In this case, backup rollers 35a and 35b are provided in the vicinity of the heating roller 28 and the pressure roller 32 to urge the applied pressure. Further, of the heating roller 16 and the pressure roller 20, only the heating roller 16 is replaced with a heating belt, and the recording medium P is pressed by the pressure roller while being conveyed with the recording surface being in contact with the heating belt. Also good. By providing the heating belt in place of the heating roller 16 in this way, it is possible to ensure a long time during which the recording medium P is heated, and sufficient heating can be performed.
[0053]
Further, in this embodiment, the surface pressure on the heating roller 16 and the pressure roller 20 is adjusted by adjusting the hardness of the material such as rubber forming the backup rollers 22a and 22b. The surface pressure may be adjusted by adjusting.
[0054]
Next, a second embodiment of the present invention will be described with reference to FIGS. Since this embodiment is the same as the first embodiment except for the structure of the fixing unit, the following description will focus on differences from the first embodiment.
[0055]
In the present embodiment, as shown in FIG. 4, the fixing unit 36 includes a reverse-crown-shaped heating roller 37 and a pressure roller 38 in which the diameter of the central portion in the axial direction is smaller than the diameters of both ends. ing. In this case, the gap between the heating roller 37 and the pressure roller 38 is 0.1 mm or less in the central portion in order to prevent the recording medium from wrinkling and to perform sufficient heating and pressing. Is desirable. In the vicinity of the heating roller 37 and the pressure roller 38, the length is approximately the same as that of the heating roller 37 and the pressure roller 38, and the shaft extends along the curved shape of the peripheral surface of the heating roller 37 and the pressure roller 38. Backup rollers 39a and 39b formed in a regular crown shape in which the diameter of the central portion in the direction is larger than the diameter of both end portions are provided so as to contact the peripheral surfaces of the heating roller 37 and the pressure roller 38.
[0056]
Since other configurations are the same as those of the first embodiment, description thereof is omitted.
[0057]
Next, the operation of this embodiment will be described.
When the image recording is completed and the recording medium cut to a predetermined length is sent to the fixing unit, the recording medium passes between a heating roller 37 and a pressure roller 38 heated by a heater (not shown). Thus, the recording medium is heated and pressurized. By applying heat and pressure with the reverse crown-shaped heating roller 37 and pressure roller 38, heat can be uniformly transmitted to the entire recording medium and the entire recording medium can be pressurized with uniform pressure, and the recording medium is wrinkled. Can be prevented.
[0058]
Further, at the time of this heating and pressing, the backup rollers 39a and 39b press the heating roller 37 and the pressing roller 38 to urge the pressing force. By using the back-up rollers 39a and 39b having a regular crown shape along the shapes of the peripheral surfaces of the heating roller 37 and the pressure roller 38, sufficient pressure is uniformly applied to the heating roller 37 and the pressure roller 38. be able to. Further, the end portions of the backup rollers 39a and 39b do not come into contact with the surfaces of the heating roller 37 and the pressure roller 38 as compared with the case where the backup rollers 39a and 39b are formed in a simple cylindrical shape. The surface can be prevented from being damaged.
[0059]
By applying sufficient heat and pressure to the recording medium, the thermoplastic resin particles on the surface of the recording medium are melted and smoothed to form a glossy image. The recording medium that has been heated and pressed is transported along the transport path and sequentially discharged from the discharge port.
[0060]
According to the present embodiment, by uniformly heating and pressurizing the entire recording medium, wrinkles can be prevented from occurring on the surface of the recording medium, and beautiful glossy and high-quality image recording can be performed.
[0061]
In the present embodiment, the lengths of the backup rollers 39a and 39b in the longitudinal direction are formed to be substantially the same as the lengths of the heating roller 37 and the pressure roller 38. The shapes of 39a and 39b are not limited to this, and may be formed in a length shorter than the length of the heating roller 40 and the pressure roller 41 as shown in FIG. Even in this case, since the backup rollers 42a and 42b are formed in a regular crown shape, the ends of the backup rollers 42a and 42b do not touch the surfaces of the heating roller 40 and the pressure roller 41, and the heating roller 40 and the pressure roller It is possible to prevent the surface of 41 from being damaged.
[0062]
Note that the present invention is not limited to the present embodiment, as in the first embodiment.
[0063]
Next, a third embodiment of the present invention will be described with reference to FIGS. Since this embodiment is the same as the first embodiment except for the structure of the fixing unit, the following description will focus on differences from the first embodiment.
[0064]
In this embodiment, the fixing unit 43 is positioned in the vicinity of the heating roller 44 and the pressure roller 45 formed in a cylindrical shape, and the heating roller 44 and the pressure roller 45, and presses and urges them from the outside. Backup rollers 46a and 46b. The backup rollers 46a and 46b have substantially the same length as the heating roller 44 and the pressure roller 45, and are formed in a regular crown shape in which the diameter of the central portion in the axial direction is larger than the diameter of both end portions. The substantially central portion is provided so as to be in contact with the substantially central portion of the peripheral surface of the heating roller 44 and the pressure roller 45.
[0065]
Since other configurations are the same as those of the first embodiment, description thereof is omitted.
[0066]
Next, the operation of this embodiment will be described.
When the image recording is completed and the recording medium cut to a predetermined length is sent to the fixing unit 43, the recording medium passes between a heating roller 44 and a pressure roller 45 heated by a heater (not shown). By doing so, the recording medium is heated and pressurized. At that time, the backup rollers 46a and 46b press the heating roller 44 and the pressure roller 45 to urge the pressing force. As a result, the thermoplastic resin particles on the surface of the recording medium are melted and smoothed to form a glossy image. The recording medium that has been heated and pressed is transported along the transport path and sequentially discharged from the discharge port.
[0067]
In addition, since the other structure is the same as that of the first embodiment, the same parts are denoted by the same reference numerals and the description thereof is omitted.
[0068]
According to this embodiment, since the backup rollers 46a and 46b are formed in a regular crown shape, the pressing force can be uniformly applied to the heating roller 44 and the pressure roller 45 by the central portion in the axial direction. It is possible to uniformly heat and press the recording medium. As a result, it is possible to perform high-quality image recording with gloss evenly throughout.
[0069]
In the present embodiment, the lengths of the backup rollers 46a and 46b in the longitudinal direction are formed to be substantially the same as the lengths of the heating roller 44 and the pressure roller 45. The shape of 46a, 46b is not limited to this, and as shown in FIG. 7, it may be formed in a length dimension shorter than the length dimension of the heating roller 47 and the pressure roller 48. Even in this case, since the backup rollers 49a and 49b are formed in a regular crown shape, the end portions of the backup rollers 49a and 49b do not touch the surfaces of the heating roller 47 and the pressure roller 48, and the heating roller 47 and the pressure roller. The surface of 48 can be prevented from being damaged.
[0070]
In addition, the present invention is not limited to this embodiment, as in the first embodiment and the second embodiment.
[0071]
【The invention's effect】
  As described above, according to the invention described in claim 1, since the pressure is applied to the recording medium by the pressure roller having a small arithmetic average roughness of the surface, the thermoplastic resin layer of the recording medium is melted. The surface can be smoothed without unevenness. As a result, there is an effect that a glossy high-definition image can be formed on the surface.
  Further, since the arithmetic average roughness of the backup roller surface is small, the surface of the heating roller and the pressure roller is not damaged by the pressure of the backup roller when the recording medium is pressed. For this reason, when a recording medium containing thermoplastic resin particles is heated and pressurized, the surface of the recording medium is not uneven, and a glossy and high-quality image can be formed.
[0073]
  Also,Claim 2Since the surface pressure between the backup roller, the heating roller and the pressure roller is low, it is formed on the surface of the heating roller when the heating roller and the pressure roller are pressed by the backup roller. The release layer is not worn or damaged. For this reason, the surface of the recording medium is not damaged by the damaged release layer, and an effect of enabling high-quality image formation is obtained.
[0074]
  further,Claim 3According to the invention described in the above, the backup roller performs cleaning such as adsorption removal of dust adhering to the surfaces of the heating roller and the pressure roller, so there is no need to provide a separate cleaning roller, and the structure inside the apparatus is simplified. In addition, the size can be reduced. In addition, since the cleaning roller is expensive, it is possible to reduce the apparatus cost by performing cleaning of the roller without providing the cleaning roller.
[0075]
  Also,Claim 4In the invention described in the above, when the shape of the heating roller and the pressure roller is an inverted crown shape, the back-up roller has a regular crown shape that conforms to this, thereby uniformly heating and pressing the recording medium. Can be done. Also, stress does not concentrate on the end of the backup roller, and even if the length of the backup roller is shorter than that of the heating roller and the pressure roller, the surface of the heating roller and the pressure roller is pressed without being damaged. be able to. This produces an effect that a glossy and high-quality image can be formed on the surface of the recording medium.
[0076]
  Also,Claim 5In the invention described in the above, even when the backup roller has a regular crown shape, stress is not concentrated on the end of the backup roller, and the length of the backup roller is shorter than that of the heating roller and the pressure roller. The surface of the heating roller and the pressure roller can be pressed without scratching. This produces an effect that a glossy and high-quality image can be formed on the surface of the recording medium.
[0077]
According to the sixth aspect of the present invention, after recording an image, the recording medium surface is heated and pressurized to melt the thermoplastic resin particles on the surface of the recording medium, thereby obtaining a glossy photo-quality image. The effect that it can be obtained.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing an entire image recording apparatus according to the present invention.
FIG. 2 is a diagram schematically showing a fixing unit of the first embodiment of the image recording apparatus according to the present invention.
FIG. 3 is a cross-sectional view schematically showing a modification of the fixing unit of the first embodiment of the image recording apparatus according to the present invention.
FIG. 4 is a diagram schematically illustrating a fixing unit according to a second embodiment of the image recording apparatus according to the invention.
FIG. 5 is a diagram schematically showing a modification of the fixing unit of the second embodiment of the image recording apparatus according to the present invention.
FIG. 6 is a diagram schematically showing a fixing unit of a third embodiment of the image recording apparatus according to the present invention.
FIG. 7 is a diagram schematically showing a modification of the fixing unit of the third embodiment of the image recording apparatus according to the present invention.
[Explanation of symbols]
1 Image recording device
15 Fixing unit
16 Heating roller
17 Heater
18 Release layer
20 Pressure roller
22a, 22b Backup roller

Claims (6)

A recording head that discharges ink onto the recording medium; a heating roller that is disposed downstream of the recording head in the conveyance path of the recording medium and that heats the recording medium; and a position that faces the heating roller. An arithmetic average roughness (Ra) of the surfaces of the heating roller and the pressure roller is 0.5 μm or less, and image recording is performed while conveying the recording medium in a certain direction. In an image recording apparatus that performs
A backup roller that presses and urges the heating roller and the pressure roller;
The image recording apparatus according to claim 1, wherein the backup roller has an arithmetic average roughness (Ra) of 0.5 μm or less on a surface thereof . The surface pressure between the backup roller and the heating roller and the surface pressure between the backup roller and the pressure roller are less than or equal to the surface pressure between the heating roller and the pressure roller. The image recording apparatus according to claim 1 . The image recording apparatus according to claim 1 , wherein the backup roller also serves as a cleaning roller that cleans surfaces of the heating roller and the pressure roller. The shape of the backup roller is a regular crown shape that follows the shape of the heating roller and the pressure roller when the shape of the heating roller and the pressure roller is an inverted crown shape. The image recording apparatus according to any one of claims 1 to 3 . The image recording apparatus according to claim 1, wherein the backup roller has a regular crown shape. 6. The image recording apparatus according to claim 1 , wherein the recording medium is a recording medium having a layer containing thermoplastic resin particles on a recording surface side.

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