JP2006175348A - Spray application method, spray application apparatus, and ink jet recording paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spray application method on the surface layer of recording papers which is easy to confirm the spray conditions, reduces the loss of a supporter and coating solution and prevents the application failure in forming a surface layer by a spray application apparatus and manufacturing recording paper, to provide a spray application apparatus for surface layer application and to provide a recording paper. <P>SOLUTION: In the spray application method of the surface layer of the ink jet recording paper which comprises spray-applying the coating solution by the spray application apparatus and forming the surface layer on the ink jet absorbing layer of the supporter supported by a backup roll to continuously carry, the spray application apparatus has a spray coater, a monitoring means and a coating solution spreading prevention means and bringing the opening of the coating solution spreading prevention means into contact with the wall face of the width direction of the spray coater; wherein the area of the opening is 100-700% based on the sprayed area and the gas suction amount is 100-300% based on the gas suction amount of the spray coater. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface layer of an ink jet recording paper (hereinafter also referred to simply as a recording paper) in which a surface layer is formed on an ink absorbing layer by spraying a coating liquid on the ink absorbing layer formed on a support. The present invention relates to a spray coating method, a spray coating apparatus for coating a surface layer, and a recording sheet.

  Inkjet recording is a method in which micro droplets of ink are ejected by various operating principles and deposited on recording paper to record images, characters, etc., but they are relatively high speed, low noise, and easy to multicolor. It has some advantages. In particular, since the image quality of printers has recently improved and has reached photographic image quality, the recording paper also realizes photographic image quality and reproduces the texture (glossiness, smoothness, stiffness, etc.) of silver halide photography. Is required.

  As one method for reproducing the texture of a silver salt photograph, a so-called swelling type recording paper is known in which a hydrophilic binder such as gelatin or polyvinyl alcohol is coated on a support. However, the recording paper produced by this method has drawbacks such as a slow ink absorption speed, a sticky surface after printing, and an image that tends to bleed due to humidity during storage. In particular, since the ink absorption speed is slow, ink droplets mix before being absorbed, and it is easy to cause bleeding between different colors (bleeding) and uneven color within the same color (beading). It is very difficult to obtain a degree of image quality.

  The so-called void type is becoming the mainstream instead of the above swelling type, and the ink absorption layer has porous inorganic fine particles, and the ink is absorbed by the porous inorganic fine particles, so the absorption speed is fast. Is a feature. Examples of such void-type recording paper include JP-A-10-119423, JP-A-10-119424, JP-A-10-175364, JP-A-10-193976, JP-A-10-19376, and JP-A-10-217601. 11-20300, 11-106694, 11-321079, 11-348410, 10-178126, 11-348409, JP-A-2000-27093, 2000-94830, 2000- 158807, 2000-211121, etc.

  On the other hand, in addition to image quality and texture, demands for durability and image storage stability have become higher, and many attempts have been made to reach the silver salt photography level in terms of light resistance, moisture resistance, water resistance, and the like. Examples of the improvement in light resistance include JP-A-57-74192, JP-A-57-87989, JP-A-57-74193, JP-A-58-152072, JP-A-1-95091, JP-A-1-95091 and JP-A-1-95091. 115677, 3-13376, 4-7189, 7-195824, 8-25796, 11-321090, 11-277893, JP-A-2000-37951, and the like. A number of techniques have been disclosed.

  In the case of a void type recording paper, there is not only light resistance but also a problem that it easily causes discoloration due to a trace amount of active harmful gas in the air such as ozone, oxidant, SOx, NOx due to the void structure. In particular, discoloration tends to occur with phthalocyanine-based aqueous dyes used in general color ink jet printers.

  As described above, a method of providing a surface layer on the ink absorption layer has been studied as one of countermeasures for the problems caused by the void structure of the ink absorption layer. Providing a surface layer is effective because it does not allow a very small amount of active harmful gas in the air, such as ozone, oxidant, SOx, and NOx, to enter the void structure, and is described in JP-A-7-237348. As shown, a technique of providing a transparent polymer film having a thickness of 0.5 to 30 μm is known.

  As a method for providing the surface layer, the coating liquid is applied on the ink absorbing layer by block coating, gravure roll coating, extrusion coating, or the like.

  1) The operating rate is low because it is difficult to make the coating speed 50 m / min or more.

  2) Interference unevenness is likely to occur on the coated surface, resulting in a low commercial value.

  3) The film thickness distribution is unstable and it is difficult to obtain a uniform film thickness layer, which is disadvantageous for preventing invasion of harmful gases.

  4) Since it is difficult to apply a thin film having a film thickness of 5 to 20 μm, the recording paper is colored due to the influence of the film thickness. In addition, the load in the drying process increases.

  For these reasons, the surface layer for preventing invasion of harmful gases is applied as a thin and uniform coating method by spray coating using a spray coater. For example, when a coating liquid is sprayed by a spray device over a coating width in a direction intersecting the substrate transport direction to form a coating liquid layer (surface layer) on the substrate, spraying is performed to prevent the sprayed coating liquid from scattering. There is known a spray coating method and a spray coating apparatus using a spray device disposed in a casing in which a coater is held at a reduced pressure (see, for example, Patent Document 1).

  In the case of the spray coating apparatus described in Patent Document 1, there is an effect in preventing scattering of the coating solution sprayed over the entire coating process, however, it has the following problems.

  1) Since the spray coating device is arranged in a sealed casing, it is necessary to adjust the spray state of the coating liquid of the spray coater while actually checking the state of application on the support. The loss of coating liquid is large.

  2) Depending on the degree of decompression in the housing, there is a high risk that the droplet of the coating liquid in the spray state is sucked before reaching the support and the coating yield is reduced.

  3) There is a risk that the coating liquid adhering to the wall in the casing during application drops on the coating film, causing a failure.

  4) Sprayed droplets of the sprayed coating liquid that was not used for coating scatter from the gap between the housing that houses the spray coating device and the support, and the scattered droplets reattached to the support to cause uneven coating. There is a risk of generating. In addition, the scattered droplets may contaminate the spray coating process.

  5) Due to the spray pressure at the time of spray application, the support may flutter, and there is a risk of scraping off the ink absorption layer due to poor transport of the support and the coating liquid surface immediately after application due to contact with the housing.

From such a situation, when the recording liquid is coated on the at least one ink absorption layer formed on the support by spraying the coating liquid with a spray coating device to form a surface layer, the recording paper is manufactured. The condition of the spray coater is easy, the loss of the support and coating liquid is small, the coating yield is high, and the surface layer of the recording paper prevents the coating failure due to the drop of droplets and the flickering of the support during coating. It is desired to develop a spray coating method, a spray coating apparatus for coating a surface layer, and a recording paper.
JP 2004-90330 A

  The present invention has been made in view of the above circumstances, and its object is to coat a coating liquid by spraying a coating liquid on at least one ink absorbing layer formed on a support with a spray coating device. When recording sheets are formed by forming a surface layer, it is easy to check the spray state of the coating liquid of the spray coater, the loss of the support and coating liquid is small, the coating yield is high, and the coating failure is prevented. It is an object to provide a spray coating method for a surface layer of a paper, a spray coating device for coating the surface layer, and a recording paper.

  The above object of the present invention has been achieved by the following constitution.

(Claim 1)
On the at least one ink absorbing layer formed on the support that is supported by the backup roll and continuously conveyed, a spray coating device disposed at a position intersecting the conveying direction of the support is used to form the ink absorbing layer. In the spray coating method of the surface layer of the ink jet recording paper, the surface layer is formed by spray coating the coating liquid over the entire width in the width direction.
The spray coating device is disposed outside the drying process, and includes a spray coater, a monitoring unit, and a coating liquid scattering preventing unit.
The coating liquid scattering prevention means includes a box-structured main body having an opening on the spray coater side, suction means connected to the main body, recovery means, and a support having an ink absorption layer on the backup roll; Gas supply means for supplying gas to a gap with the lower surface of the main body, the spray coater so that the opening is brought into contact with the wall surface in the width direction of the spray coater and is close to the outer peripheral surface of the backup roll Are disposed either on the downstream side or on the upstream side of
The area of the opening is 100 to 700% with respect to the spray area,
The spray application method is characterized in that a gas suction amount of the suction means is 100 to 300% with respect to a gas supply amount of the spray coater.

(Claim 2)
2. The spray coating method according to claim 1, wherein a rectifying means is disposed inside the main body.

(Claim 3)
3. The monitoring device according to claim 1, wherein the monitoring unit is disposed at a position facing the coating liquid scattering preventing unit, constantly monitoring a spray state of the spray coater, and feeding back an abnormal application point to an application record. Spray application method.

(Claim 4)
The said coating liquid scattering prevention means moves to the arrangement | positioning position from a standby position according to the movement from the standby position of a spray coater to an application position, The any one of Claims 1-3 characterized by the above-mentioned. Spray application method.

(Claim 5)
The spray coating method for a surface layer according to any one of claims 1 to 4, wherein the spray coater is a curtain spray coater.

(Claim 6)
The spray coating method according to claim 1, wherein the ink absorption layer is composed of a porous layer containing at least one inorganic fine particle and a binder.

(Claim 7)
In a spray coating apparatus for coating a surface layer of inkjet recording paper, a coating layer is spray-coated on at least one ink absorbing layer formed on a support that is supported by a backup roll and continuously conveyed. ,
A spray coater, a monitoring unit, and a coating solution scattering prevention unit, disposed outside the drying process,
The coating liquid scattering prevention means includes a box-structured main body having an opening on the spray coater side, suction means connected to the main body, recovery means, and a support having an ink absorption layer on the backup roll; Gas supply means for supplying gas to a gap with the lower surface of the main body, the spray coater so that the opening is brought into contact with the wall surface in the width direction of the spray coater and is close to the outer peripheral surface of the backup roll Are disposed either on the downstream side or on the upstream side of
The area of the opening is 100 to 700% with respect to the spray area,
The spray coating apparatus is characterized in that a gas suction amount of the suction means is 100 to 300% with respect to an air supply amount of the spray coater.

(Claim 8)
The spray coating apparatus according to claim 7, wherein a rectifying means is disposed inside the main body.

(Claim 9)
9. The monitoring device according to claim 7 or 8, wherein the monitoring unit is disposed at a position facing the coating liquid scattering preventing unit, constantly monitoring a spray state of the spray coater, and feeding back an abnormal coating position to a coating record. Spray application equipment.

(Claim 10)
The said coating liquid scattering prevention means moves to the arrangement | positioning position from a standby position according to the movement from the standby position of a spray coater to an application position, The any one of Claims 7-9 characterized by the above-mentioned. Spray application device.

(Claim 11)
11. The surface layer spray coating apparatus according to claim 7, wherein the spray coater is a curtain spray coater.

(Claim 12)
The spray coating apparatus according to claim 7, wherein the ink absorption layer is composed of a porous layer containing at least one inorganic fine particle and a binder.

(Claim 13)
An ink jet recording paper produced by the surface layer spray coating method according to claim 1.

  When the recording liquid is produced by spraying the coating liquid on the at least one ink absorbing layer formed on the support by spraying the coating liquid with a spray coating apparatus to form a surface layer, the coating liquid for the spray coater Is easy to check the spray state, the loss of the support and coating liquid is low, the coating yield is high, the coating layer surface coating of the recording paper that prevents coating failure, spray coating device for surface layer coating, It is possible to provide a recording paper surface layer spray coating method, surface layer coating spray application device, and recording paper that can provide recording paper, which can reduce costs, improve production efficiency, and improve quality became.

  Embodiments of the present invention will be described with reference to FIGS. 1 to 7, but the present invention is not limited thereto.

  FIG. 1 is a schematic diagram showing an example of a recording paper coating production line in which a spray coating device is arranged. In the figure, 1 indicates a coating production line. The coating production line 1 has a surface on the feeding part 2 of the support, the first coating part 3 for applying the coating liquid for forming the ink absorbing layer, the cooling part 4, the drying part 5, and the ink absorbing layer. It has the 2nd coating part 6 which spray-coats the coating liquid which forms a layer, and the winding-up part 7. FIG.

  Reference numeral 202 denotes an original roll of the support 201. The support 201 fed out from the feed-out unit 2 is coated with the coater 302 to form at least one ink absorbing layer on the support 201 wound around the backup roll 301 in the first coating unit 3. . The ink absorbing layer is preferably composed of a porous layer containing at least one inorganic fine particle and a binder. The coater 302 is preferably a flow-rate type slide bead coating apparatus because it can simultaneously apply a plurality of coating liquids.

  The support having the coating liquid layer for forming the ink absorbing layer on the support 201 is in a state where the coating liquid for the ink absorbing layer contains a hydrophilic binder and is fixed by the cooling device 401 in the cooling unit 4. Then, the ink is transported to the drying unit 5 where the solvent is removed and the ink absorbing layer 203 is formed. Reference numeral 501 denotes a drying box, 502 denotes a conveyance roll, and 503 denotes a reverser that reversely conveys the gas for floating and conveying the support in a non-contact manner with the surface of the coating film in order to avoid contact with the coating surface. . Thereby, it is possible to dry by avoiding contact of the coated surface.

  At the stage where the solvent in the coating liquid layer is removed and the ink absorbing layer 203 is formed in the drying unit 5, the second coating having the back-up roll 605 disposed outside the drying unit 5 and the spray coating device 601. In the construction section 6, the coating liquid for the surface layer is spray-coated by the spray coating device 601 on the ink absorbing layer 203 of the support wound around the back up roll 605. The spray coating apparatus 601 includes a spray coater 602, coating liquid scattering prevention means 603, and monitoring means 604. A spray coater 602 is preferable as a spray coater 602 for coating the surface layer of the recording paper of the present invention. Hereinafter, the spray coater 602 refers to a curtain spray coater.

  The coating liquid splash preventing means 603 may be disposed on either the downstream side or the upstream side of the spray coater 602, and this figure shows the case where it is disposed on the downstream side of the spray coater 602. The monitoring unit 604 is disposed at a position facing the coating liquid scattering preventing unit 603 across the spray coater 602, and can constantly monitor the spray state of the coating liquid from the spray coater 602 during coating. . The spray coating apparatus 601 will be described in detail with reference to FIG.

  The support coated with the coating solution for the surface layer enters the drying box again and is dried, the solvent of the coating solution for the surface layer is removed, the surface layer 204 is formed, exits from the drying box, and is wound up. The roll-shaped recording paper 702 is manufactured by being wound around the winding core 701 by the section 7. The drying in the drying section is preferably performed by blowing hot air (the hot air blowing means is not shown). In the present invention, the surface layer formed on the ink absorption layer includes a state where a part of the surface layer penetrates into the ink absorption layer when the coating liquid is spray-coated on the ink absorption layer.

  The position where the second coating unit 6 is disposed is particularly limited as long as it can be dried again after coating in the middle of the drying process, preferably after the rate-decreasing drying, and outside the drying unit. There is no. For example, the drying unit shown in the figure may be divided into two parts, a first drying unit and a second drying unit, and arranged between the first drying unit and the second drying unit, or as shown in the figure. Although it may be arranged on the upper part of the drying box of the drying part, it is preferably arranged on the upper part of the drying box of the drying part in order to accommodate the members constituting the second coating part 6 without increasing the process. . The spray coater 602 of the spray coating device 601 of the second coating unit 6 is disposed so as to face the coating surface of the support that is a direction orthogonal to the transport direction. The following effect is acquired by taking out the 2nd coating part 6 out of a drying part, and apply | coating a surface layer on the ink absorption layer on the support body supported by the backup roll.

  1) Because the coating liquid splashes due to spray coating can prevent contamination of the transport roll and the inner wall of the drying box, foreign matter adherence due to transfer of the foreign matter attached to the transport roll, and foreign matter adhesion due to the fall of foreign matter from the inner wall of the dry box can be prevented. Product performance is stabilized.

  2) Since the drying part is not enlarged, the loss of energy required for drying can be minimized.

  3) Maintenance of the spray coating device is facilitated.

  4) Since the coating is carried out while being supported by the backup roll, there is no fluttering of the support and stable coating is possible, and the product performance is stabilized.

  FIG. 2 is an enlarged schematic plan view of a portion indicated by X in FIG.

  In the figure, reference numeral 602a denotes a coating liquid supply pipe of the spray coater 602. In this figure, the air supply pipes 602b and 602c (see FIG. 3) are omitted. Reference numeral 603a denotes a main body of the coating liquid scattering preventing means 603, and reference numeral 603b (603c) denotes a suction pipe which is a suction means for reducing the pressure inside the main body 603a. Other symbols are the same as those in FIG. The monitoring means 604 is disposed at a position facing the coating liquid scattering preventing means 603 across the spray coater 602. The coating liquid scattering preventing means 603 has a tip 603a1 of the main body 603a on the wall surface 602b in the width direction of the spray coating machine 602. It arrange | positions so that it may contact.

  Examples of the monitoring unit 604 include a high-speed video camera (manufactured by PHOTRON), a CCD camera (manufactured by ELMO), and the like. Since the monitoring unit 604 needs to monitor the spray state of the full width of the spray coater 602, the number of installed units can be appropriately changed according to the performance of the monitoring unit 604 and the size of the spray coater 602. This figure shows a case where two monitoring means 604 are arranged to monitor the spray state of the spray coater 602 by dividing it into two from the center.

  The monitoring means 604 is preferably set so that it always operates from the spray condition setting of the spray coater 602 to the end of application. The information from the monitoring means 604 is set so as to be linked with the application time from the start of application, and is managed by a control device (not shown) so that the abnormality occurrence time and position can be known when an abnormality occurs in the spray state. Yes. After the application is completed, the presence or absence of application abnormality can be confirmed by confirming the spray state from the start to the end of application from a control device (not shown).

  It is preferable that the spray coater 602 can be moved from a standby position (a position of the spray coater indicated by a dotted line) to a coating position by moving means (not shown) at the start of coating. Similarly to the spray coater 602, the coating liquid splash preventing means 603 is moved from the standby position (the position of the coating liquid splash preventing means indicated by the dotted line) to the coating position of the spray coater 602 by a moving means (not shown). Preferably it is possible. It is preferable that the monitoring means 604 can also be moved from the standby position (position of the monitoring means indicated by the dotted line) to the application position of the spray coater 602 by the moving means (not shown) at the start of application. The spray coater 602, the coating liquid splash preventing means 603, and the monitoring means 604 may be moved individually, or may be moved in accordance with the movement of the spray coater 602, for example.

  θ1 represents an angle at which the spray coater 602 and the support 201 (see FIG. 1) intersect. In the present invention, “crossing” means an angle at which a line forming the spray port P (see FIG. 5) of the spray coater 602 is parallel to the support and crosses the traveling direction of the support. That is, it means that the spray coater 602 is disposed at a position that intersects the conveying direction of the support (the arrow direction shown in FIGS. 1 and 3). The angle θ1 is preferably 70 to 110 ° in consideration of the application range of the coating liquid and the ease of setting the spray conditions of the coating liquid. In the case of this figure, the case where the angle at which the spray coater 602 and the support intersect is 90 °.

  The spray port P (see FIG. 5) of the coating liquid of the spray coater 602 is at least the coating width of the ink absorbing layer 203 (see FIG. 3) on the strip-shaped support (the direction intersecting the transport direction of the strip-shaped support). It preferably has a length corresponding to the length of the coated portion of the belt-like support in FIG. By arranging in this manner, the belt-shaped support is conveyed to the spray coater 602, and the coating liquid is sprayed over the coating width onto the ink absorbing layer 203 (see FIG. 3) on the belt-shaped support, The drying load is small, the film thickness uniformity is high, and a thin coating film can be applied.

  FIG. 3 is a schematic enlarged view of a portion indicated by X in FIG.

  In the figure, reference numerals 602b and 602c denote air supply pipes. The coating liquid splash preventing means 603 includes a box-shaped main body 603b having an opening 603a on the spray coater 602 side, suction pipes 603c and 603d as suction means for reducing the pressure inside the main body 603b, A coating liquid collection tube 603e which is a means for collecting the coating liquid collected in the main body 603b which is not used, a support body 201 (see FIG. 1) having the ink absorbing layer 203 on the backup roll 605, and a lower surface 603b1 of the main body 603b. Gas supply means 607 for supplying a gas to the gap 606. The main body 608 is sucked by the suction pipe 603c and the suction pipe 603d, and when the pressure of the main body 603b is reduced, the flow of the air from the opening 603a is adjusted to efficiently collect the sprayed and used coating liquid. The rectification | straightening plate of the rectification | straightening means provided inside the upper surface 603b2 of 603b is shown. The rectifying plate 608 will be described in detail with reference to FIG.

  The material of the coating liquid splash preventing means 603 is not particularly limited as long as it has resistance to the solvent used in the coating liquid, and examples thereof include acrylic resin, stainless steel, and aluminum. The material of the rectifying plate that is the rectifying means is not particularly limited as long as it is resistant to the solvent used in the coating liquid. For example, the same material as that of the coating liquid scattering preventing means 603 may be used. It doesn't matter.

  The area of the opening 603a is 100 to 700% with respect to the spraying area for spraying the coating liquid. When the area of the opening 603a is less than 100%, the flow rate during gas suction becomes higher than necessary, and the air flow between the spray coater and the support becomes turbulent and spraying is not performed uniformly. This is not preferable because uneven coating occurs. In addition, the gas flow becomes turbulent, and some of the sprayed coating liquid droplets are scattered before reaching and rubbing the support, and uniform spraying cannot be performed, and coating unevenness occurs. This is not preferable because the coating amount is reduced and the coating yield is lowered. When the area of the opening 603a exceeds 700%, the gas suction pressure for preventing the coating liquid from scattering must be sucked at a pressure higher than the tension of the support acting on the backup roll. This is not preferable because uniform spray coating cannot be performed and uneven coating occurs. Also, since the suction pressure is increased, a part of the sprayed droplets of the coating liquid is sucked before reaching the support and rubbed, the amount applied to the support is reduced, and the coating yield is lowered, which is not preferable. .

  The coating yield was determined by calculation from measured concentration / theoretical concentration × 100. The measured concentration was measured at 10 points in the width direction at intervals of 10 m from the start of application of the sample to the end of application, and an average value was obtained from all measured values. The theoretical concentration was obtained by preparing a calibration curve in which the relationship between the coating film thickness and the concentration was known in advance.

  In the present invention, the area of the opening 603a refers to the area obtained by multiplying the height L of the opening 603a (see FIG. 4) and the length of the long side of the spray coater, and the distance between the spray coater and the support. And the area which added the space | interval of the length of the longitudinal direction.

  A spray area means the area where the coating liquid sprayed from the spray port P (refer FIG. 5) arrived at the support body.

The supply amount of the gas from the gas supply means 607, for example, when the inner pressure reduction degree of the body 603b is -3.4KPa is preferably 1.5m ³ / min~4m ³ / min. If the supply amount of gas is less than 3 m ³ / min, if the supply amount of the coating liquid is large, spray droplets cannot be sucked only by suction in the cover, and spray droplets are not generated from the gap between the support and the cover. It may leak, adhere to the support and cause uneven coating. In addition, droplets adhering to the inner side of the main body 603b may condense and become a bowl shape and hang down on the support, resulting in density unevenness. When the supply amount of gas exceeds 6 m ³ / min, excessive resistance is given to the coating liquid sprayed from the nozzle, and the coating liquid may not be in a constant sprayed state, resulting in uneven density.

  The suction pipe 603c and the suction pipe 603d are connected to a vacuum pump (not shown), and the inside of the main body 603b can be decompressed. The coating liquid recovery pipe 603e is connected to a recovery container (not shown). The gas suction amount of the suction tube 603c and the suction tube 603d is 100 to 300% with respect to the air supply amount of the spray coater. If it is less than 100% with respect to the air supply amount, it is not preferable because droplets of the spray-like coating liquid that is not sucked by the coating liquid scattering prevention means adhere to the support and cause uneven coating. When the air supply amount exceeds 300%, the sprayed coating liquid droplets are sucked to the coating liquid scattering prevention means more than necessary, and the coating rate on the support is lowered. This is not preferable because the rate decreases.

  The pressure reduction degree inside the main body 603b is preferably −2 to −6 KPa. When the degree of vacuum is less than −2 KPa, the spray droplets of the coating liquid that has not been applied onto the ink absorption layer are scattered without being collected and reattached onto the ink absorption layer, resulting in uneven coating. Or may make the surroundings dirty. When the degree of vacuum exceeds -6 KPa, most of the sprayed coating liquid is collected, and the coating rate on the ink absorbing layer may be reduced, resulting in poor coating. In addition, the support being transported may flutter, causing transport failure and contact by the coating liquid scattering preventing means, which may cause a failure.

  By being sucked by the suction pipe 603c and the suction pipe 603d, the sprayed coating liquid sprayed from the spray coater 602 and not involved in the coating adheres to the inside of the main body 603b without being scattered and becomes droplets, and the coating liquid recovery pipe 603e. It collect | recovers to a collection container (not shown) via. Reference numeral 603f denotes an adsorbing member stretched near the inside of the opening 603a of the main body 603b.

  As the adsorbing member, a polymer absorbent (Supersorbent Polymer: SAP), for example, a starch-based graft polymer, a carboxyl methylated product, a cellulose-based graft polymer, a carboxyl methylated product, or a polyacrylic acid based synthetic polymer , Polyacrylate-based, polyvinyl alcohol-based, polyacrylamide-based, polyoxyethylene-based, isobutylene maleate-based, etc., or their respective composites, or starch-based, cellulose-based, and synthetic polymer-based mixtures Etc. As an example, when sodium polyacrylate resin is used, when water is absorbed, sodium ions are discharged from the polymer network, and water flows into the gaps in the polymer network that are enlarged due to electron repulsion between carboxylate ions in the polymer side chain. Absorption effect. In addition, as other water-absorbing carriers, for example, sanitary products such as paper diapers and sanitary products as described in the magazine “Surface, Vol. 33, No. 4, 52-59, (1995)”, soil water retention materials It is also possible to use various superabsorbent polymers used for agricultural and horticultural supplies.

  The adsorbing member 603f makes it possible to prevent droplets of the coating liquid adhering to the inside of the opening 603a from falling on the ink absorbing layer 203 on the support on the backup roll 605.

  4 is an enlarged schematic view of a portion indicated by Y in FIG.

  In the figure, L indicates the height of the opening 603a. It is preferable to set appropriately so that the area of the opening is 100 to 700% with respect to the spray area. M indicates the length of the current plate 608. The length M is preferably 50 to 80% with respect to the height L of the opening 603a in consideration of the spray speed of the coating liquid, the degree of pressure reduction of the coating liquid scattering prevention means, and the strength of the rectifying plate. .

  N indicates the distance from the tip of the upper side 603b2 of the main body 603b of the coating liquid scattering prevention means to the mounting position of the current plate 608. The distance N is applied to the rectifying plate by rebounding after the droplet of the coating liquid reaches the ink absorbing layer on the support, coating unevenness due to dropping of the droplet adhering to the rectifying plate onto the ink absorbing layer, spraying Considering the gas flow between the coater and the current plate, it is preferable that the distance is 5 to 30 mm from the tip of the upper side 603b2 of the main body 603b.

  O indicates the thickness of the current plate 608. The thickness O is the deflection of the rectifying plate due to the degree of decompression of the coating liquid scatter preventing means, the stability of the gas flow accompanying the deflection of the rectifying plate, the gas in the gap between the rectifying plate and the lower surface of the main body of the coating liquid scatter preventing means In consideration of the flow velocity, suction of the coating liquid droplets before reaching the ink absorbing layer on the support, the coating yield, etc., the thickness is preferably 3 to 20 mm.

  The following effects can be obtained by arranging the current plate 608 as shown in the figure.

  1) Since it is possible to prevent the sprayed coating liquid before being applied to the support from being sucked, and the application can be performed without reducing the application yield on the support, a stable application product can be obtained. It became.

  2) Dynamic pressure for reducing the pressure inside the coating liquid splash prevention means can be reduced, uniform gas flow can be achieved in the width direction of the support, and uneven coating with the width can be eliminated and stable. The coated product can be obtained.

  3) The flow velocity with the current plate can be locally increased, and the turbulent flow that occurs between the spray coater and the coating liquid splash prevention means can be suppressed, eliminating uneven coating due to air turbulence and stable coating. The product can be obtained.

  FIG. 5 is an enlarged schematic view showing a coating state of the spray coater shown in FIG. In this figure, the coating solution scattering preventing means disposed on the downstream side of the spray coater is omitted.

  In the figure, reference numeral 602a denotes a coating liquid supply pipe for supplying the coating liquid to the spray coater 602, and reference numerals 602b and 602c spray the surface layer coating liquid supplied to the spray coater 602 in the form of droplets and continuously convey them ( A pair of pressurized air supply pipes for spray coating on the ink absorbing layer 203 on the belt-like support 201 is shown.

  Reference numeral 204 denotes a surface layer formed on the ink absorbing layer 203 on the belt-like support 201. The belt-like support 201 is moved (conveyed) relative to the coating liquid discharge portion of the spray coater 602 to continuously perform coating manufacture. The spray port P of the coating liquid of the spray coater 602 is at least the coating width of the belt-like support 201 (refers to the length of the coated portion of the belt-like support in the direction intersecting the transport direction of the belt-like support). It is preferable to arrange (see FIG. 2) so as to intersect the conveying direction of the belt-like support 201. By arranging in this way, the belt-like support is conveyed to the spray coater 602, and the coating liquid is sprayed as droplets over the coating width on the belt-like support, so that the drying load is small and the film thickness is uniform. It is possible to apply a thin coating film.

  Reference numerals 602d to 602g denote blocks constituting the spray coater 602. Reference numeral 602h denotes a pressurized air pocket including a block 602d and a block 602e, and reference numeral 602i denotes an air nozzle formed in a gap between the block 602d and the block 602e. Reference numeral 602j denotes a pressurized air pocket made up of blocks 602f and 602g, and 602k denotes an air nozzle made up of blocks 602f and 602g.

  Pressurized air supplied from a pressurized air supply source (not shown) through the pressurized air supply pipes 602b and 602c is temporarily stored in the pressurized air pockets 602h and 602j, and then each air nozzle. It ejects from each opening end 602i1, 602k1 through 602i, 602k.

  Reference numeral 602l denotes a coating liquid pocket that is composed of a block 602e and a block 602f, and temporarily stores the coating liquid supplied from the coating liquid supply pipe. Reference numeral 602m denotes a coating liquid nozzle formed by a comb-shaped member 602n sandwiched in a gap between the block 602e and the block 602f. The coating liquid stored in the coating liquid pocket 602l is discharged from the opening end 602m1 of the coating liquid nozzle 602m and at the same time sprayed in a spray form by the pressurized air ejected from the opening ends 602i1 and 602k1 of the air nozzles 602i and 602k. And applied onto the ink absorbing layer 203 on the belt-like support 201. Further, the distance between the spray port P constituted by the opening ends 602i1 and 602k1 of the air nozzles 602i and 602k of the spray coater 602 and the opening end 602m1 of the coating solution nozzle 602m is approximately 2 to 2. It can be appropriately selected within a range of 50 mm. Reference numeral 8 denotes a droplet sprayed in a spray form. The comb-shaped member 602n will be described with reference to FIG.

  The area range of the coating liquid spray applied onto the ink absorbing layer 203 is preferably always uniform, but in particular, the droplet diameter distribution is uniform and the length L in the transport direction is uniform over the coating width. It is preferable. Further, it is preferable that the spread angle θ of the droplet group to be sprayed is uniform over the coating width with respect to the belt-like support with the spray port P as a base point. The collision speed falling on the ink absorption layer 203 is preferably uniform. By these, it becomes possible to ensure the uniformity of the coating film thickness. That the droplet diameter distribution is uniform in the coating width direction specifically means that the variation of the average droplet diameter is ± 20% or less in the coating width direction. More preferably, it is ± 10% or less.

  6 is an enlarged schematic view of a portion indicated by Z in FIG.

  Reference numerals in the figure are synonymous with those in FIGS. 3 and 5. In the case of this figure, as the monitoring means 604, an example in which a high-speed video camera (manufactured by PHOTRON) is used is shown. The size of the droplet 8 of the coating liquid sprayed in a spray form from the spray port P constituted by the opening ends 602i1, 602k1, and 602n1 of the spray coater 602 by the monitoring unit 604, the size distribution of the droplet 8, and the droplet The density of 8 is monitored in the width direction of the spray coater 602 and the height direction of the coating liquid to be sprayed. Information from the monitoring unit 604 is input to a CPU of a control unit (not shown), and the setting conditions (the coating speed for each coating solution to be used and the coating film thickness at the time of coating are preliminarily input to the memory) Information regarding the size of the droplet 8, the distribution of the size of the droplet 8, and the density of the droplet 8) is calculated, and when it is out of the information input to the memory, it is recorded as abnormal information. ing.

  By monitoring the spray state of the coating liquid of the spray coater 602 by the monitoring means 604 according to the present invention, the following effects can be obtained.

  1) Since it is possible to adjust the spray state of the coating liquid of the spray coater by the monitoring means at the start of coating, there is no need to check the actual coating state on the support, and the support and coating It became possible to reduce liquid loss.

  2) It is possible to immediately detect changes in the spray state due to the difference in physical properties of the coating liquid that occurs when the lot of the coating liquid changes, and it is possible to reduce the loss of the coating liquid and the loss of the coated support as much as possible. It was.

  3) Even if the spray coater is clogged by fine dust mixed in the coating liquid or supplied air, it is possible to immediately detect abnormalities in the spray state, and the coating liquid loss and the coated substrate It has become possible to reduce the loss as much as possible.

  4) By constantly monitoring the spray state, the location where the spray state abnormality occurred was clarified, the defective application portion could be easily deleted, and the work efficiency could be improved.

  FIG. 7 is a schematic exploded perspective view of the spray coater (curtain spray coater) shown in FIGS.

  In the figure, reference numerals 602e and 602f are blocks for forming a coating liquid nozzle 602m (see FIG. 5) having a predetermined distance and causing the coating liquid to flow down to the coating liquid nozzle. One block 602e has a coating liquid supply pipe 602a that receives a coating liquid supplied from a coating liquid supply source (not shown) and communicates with the coating liquid pocket 602l. The coating liquid staying in the coating liquid pocket 602l flows down through the coating liquid nozzle 602m formed between the blocks 602e and 602f. Reference numeral 602n denotes a comb-shaped member sandwiched between the block 602e and the block 602f. The slit is divided in the vertical direction between the two blocks 602e and 602f to form a plurality of coating liquid nozzles in the coating width direction. Reference numeral 601o1 denotes a comb blade.

  The block 602d is a block that forms an air nozzle 602i that sends air to the tip of the coating liquid nozzle 602m (see FIG. 5) together with the block 602e. The block 602g is a block that forms an air nozzle 602k1 (see FIG. 5) that sends air to the tip of the coating liquid nozzle 602m (see FIG. 5) together with the block 602f. The air nozzle 602i and the air nozzle 602i are formed in the coating width direction.

  Compressed air is supplied from an air supply source (not shown) to the pressurized air supply pipe 602b (602c), and once retained in the pressurized air pocket 602h (602j), it flows down with pressure through the air nozzle 602i (602k). To do.

  The coating liquid flowing down the coating liquid nozzle 602m (see FIG. 5) having the comb-shaped member 602n and the compressed air flowing down the two air nozzles 602i (602k) are connected to the jet P (see FIG. 5). The liquid droplets collide with each other to form droplets and fly onto the substrate that is the object to be coated.

  In the spray coater (curtain spray coater) used in the present invention, the gap width of the coating liquid nozzle 602m (see FIG. 5) is preferably used in the range of 50 to 300 μm. The shape of the opening end of the coating liquid nozzle 602m (see FIG. 5) may be a slit shape extending in the coating width, and may be circular or rectangular by inserting a comb-shaped member as shown in this figure. The shape of the open end can be changed depending on the shape of the comb-shaped member. When the shape of the opening end is circular or rectangular, it can be used within a gap width of the coating liquid nozzle 602m, and the pitch (interval) thereof is 100 to 3000 μm (comb blade 602n1 of the comb-shaped member 602n). (Corresponding to the interval).

  On the other hand, the gap width of the air nozzle 602i (602k) (see FIG. 5) is preferably used in the range of 50 to 500 μm. The shape of the opening end of the air nozzle 602i (602k) (see FIG. 5) may be a slit extending to the coating width, and may be circular or rectangular by inserting a comb-shaped member as shown in this figure. . The shape of the open end can be changed depending on the shape of the comb-shaped member. When the shape of the opening end is circular or rectangular, it can be used as a shape that fits within the width of the gap of the air nozzle 602i (602k) (see FIG. 5), and the pitch (interval) thereof is 100 to 3000 μm. (It corresponds to the interval between the comb blades 60n1 of the comb-shaped member 602n).

The angle of the air nozzle with respect to the coating solution nozzle is preferably in the range of 5 to 50 deg. The supply amount of the coating solution from the coating solution nozzle cannot be specified unconditionally depending on the desired coating thickness, coating solution concentration, coating speed, etc., but is generally stable and uniform coating as the coating amount on the substrate. A range of 1 to 50 g / m ² is preferable in consideration of the formation of a film and the drying load. The wet film thickness of the coating solution is preferably 1 to 50 μm, particularly preferably 5 to 30 μm.

  On the other hand, the gas ejected from the air nozzle is not particularly limited as long as it is suitable for coating. Generally, air is used, but the gas supply condition is generally 1 to 50 CMM / m (flow rate per coating width). The internal pressure at the gas nozzle at that time is preferably 10 kPa or more from the viewpoint of coating uniformity.

  The linear velocity v of air is preferably 126 to 400 m / s from the viewpoint of coating drying property and coating yield. The air linear velocity is the linear velocity of air immediately after the outlet of the air nozzle, and can be determined by measuring with a laser Doppler anemometer, for example, 1D FLV system 8851 manufactured by KANOMAX. The coating yield can be determined by the following two methods. 1) Calculated from the amount of coating liquid applied on the ink absorption layer / total amount of applied coating liquid supplied x 100 (%) That is, the amount of coating liquid applied on the ink absorbing layer is calculated from the change in mass before and after coating on the ink absorbing layer, and the total amount of coating liquid supplied is fed to the spray coater and supplied mass, that is, the feeding amount. It can be determined from the liquid flow rate x the coating time. 2) When the coating solution is colored, the theoretical concentration is previously determined experimentally from the relationship between the coating film thickness and the concentration, and is calculated from the measured concentration by the measured concentration / theoretical concentration × 100.

As the coating solution for forming the surface layer according to the present invention, it is preferable to use coating solutions described in JP-A Nos. 2004-906 and 2004-122705.
The ink absorbing layer in the present invention will be described. The ink absorbing layer being porous means having a large number of voids having a pore diameter of about 5 to 200 nm. It is preferable that the gaps are not isolated independently but are continuously connected to each other. As a definition of the void diameter in this case, for example, a measured value by a mercury intrusion method can be used. Hereinafter, a preferable porous layer will be described.

  The porous layer is mainly formed by soft aggregation of a hydrophilic binder and inorganic fine particles. Conventionally, various methods for forming voids in a film are known. For example, a uniform coating solution containing two or more kinds of polymers is coated on a support, and these polymers are phase-separated from each other in the drying process. A method of forming voids by applying a coating liquid containing solid fine particles and a hydrophilic or hydrophobic resin on a support, and after drying, the inkjet recording paper is immersed in water or a liquid containing an appropriate organic solvent. , A method of creating voids by dissolving solid fine particles, a method of forming voids in a film by applying a coating liquid containing a compound having a property of foaming during film formation, and then foaming this compound in the drying process, porous A coating solution containing porous solid fine particles and a hydrophilic binder on a support to form voids in the porous fine particles or between the fine particles, and a solid binder having a volume approximately equal to or larger than the hydrophilic binder. Particulates and or coating solution containing a particulate oil and a hydrophilic binder is coated on a support, and a method of forming an air gap between the solid particles are known. In the present invention, it is particularly preferable that the porous layer is formed by containing various inorganic solid fine particles having an average droplet diameter of 100 nm or less.

  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, 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. A white inorganic pigment etc. can be mentioned.

  The average droplet diameter of the inorganic fine particles is determined by observing the particles themselves or the particles appearing on the cross section or surface of the porous layer with an electron microscope, measuring the particle size of 1,000 arbitrary particles, and calculating a simple average value ( (Number average). Here, the particle size of each particle is represented by the diameter when a circle equal to the projected area is assumed.

  As the inorganic fine particles, it is preferable to use solid fine particles selected from silica and alumina or alumina hydrate.

  As silica that can be used in the present invention, silica synthesized by an ordinary wet method, colloidal silica, silica synthesized by a gas phase method, or the like is preferably used. Colloidal silica or fine particle silica synthesized by a vapor phase method is preferred, and among these, fine particle silica synthesized by a vapor phase method is preferred because a high porosity can be obtained. Alumina or alumina hydrate may be crystalline or amorphous, and any shape such as amorphous particles, spherical particles, and acicular particles can be used.

  The inorganic fine particles preferably have a particle size of 100 nm or less. For example, in the case of the gas phase method fine particle silica, the average droplet diameter of the primary particles of the inorganic fine particles dispersed in the primary particle state (particle size in the dispersion state before coating) is preferably 100 nm or less. More preferably, it is 4-50 nm, Most preferably, it is 4-20 nm.

  For example, Aerosil manufactured by Nippon Aerosil Co., Ltd. is commercially available as the silica synthesized by the vapor phase method in which the average droplet diameter of primary particles is 4 to 20 nm. The vapor phase fine particle silica can be dispersed to primary particles relatively easily by being sucked and dispersed in water using, for example, a jet stream inductor mixer manufactured by Mitamura Riken Kogyo Co., Ltd.

  In the present invention, a water-soluble binder can be used for the ink absorbing layer. Examples of the water-soluble binder that can be used in the present invention include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, finished strand, finished string, color ginan (κ, ι, λ, etc.). , Agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxymethyl cellulose and the like. These water-soluble binders can be used in combination of two or more.

  The water-soluble binder preferably used in the present invention is polyvinyl alcohol.

  The polyvinyl alcohol preferably used in the present invention includes, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, modified polyvinyl alcohol such as polyvinyl alcohol having a cation-modified terminal and anion-modified polyvinyl alcohol having an anionic group. Alcohol is also included.

  The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,000. The degree of saponification is preferably 70 to 100%, particularly preferably 80 to 99.5%.

  Examples of the cation-modified polyvinyl alcohol have primary to tertiary amino groups or quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol, as described in JP-A-61-110483. Polyvinyl alcohol, which is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

  Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like.

  The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.

  Anion-modified polyvinyl alcohol is, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-2060888, as described in JP-A-61-237681 and JP-A-63-330779, Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265.

  Nonionic modified polyvinyl alcohol is, for example, a polyvinyl alcohol derivative obtained by adding a polyalkylene oxide group to a part of vinyl alcohol as described in JP-A-7-9758, and described in JP-A-8-2595. And a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol. Polyvinyl alcohol can be used in combination of two or more, such as the degree of polymerization and the type of modification.

  In the present invention, it is preferable to use a polyvalent metal compound as a dye-fixing agent, and so long as the objective effect of the present invention is achieved, it does not preclude the use of a cationic polymer together with these compounds.

Examples of cationic polymers include polyethyleneimine, polyallylamine, polyvinylamine, dicyandiamide polyalkylene polyamine condensate, polyalkylene polyamine dicyandiamide ammonium salt condensate, dicyandiamide formalin condensate, epichlorohydrin-dialkylamine addition polymer, diallyldimethylammonium chloride polymers, diallyl dimethyl ammonium chloride-SO ₂ copolymer, polyvinyl imidazole, polyvinyl pyrrolidone, vinyl imidazole copolymers, polyvinyl pyridine, polyamidine, chitosan, cationized starch, vinylbenzyltrimethylammonium chloride polymers, (2-methacryloyl Oxyethyl) trimethylammonium chloride polymer, dimethylaminoethyl methacrylate Rate polymers, and the like.

  Examples include the cationic polymers described in Chemical Industry Times, August 15 and 25, 1998, and polymer dye fixing agents described in “Introduction to Polymer Drugs” issued by Sanyo Chemical Industries, Ltd.

The amount of inorganic fine particles used in the ink absorption layer depends largely on the required ink absorption capacity, the porosity of the porous layer, the type of inorganic pigment, and the type of water-soluble binder, but generally 1 m ^{2 of} recording paper. Usually, it is 5-30 g, preferably 10-25 g.

  The ratio of the inorganic fine particles and the water-soluble binder used in the ink absorption layer is usually 2: 1 to 20: 1 by mass ratio, and particularly preferably 3: 1 to 10: 1.

Further, it may contain a cationic water-soluble polymer having a quaternary ammonium base in the molecule, and is usually used in the range of 0.1 to 10 g, preferably 0.2 to 5 g per 1 m ^{2 of} the ink jet recording paper. .

In the porous layer, the total amount of voids (void volume) is preferably 20 ml or more per 1 m ² of recording paper. When the void volume is less than 20 ml / m ² , the ink absorbency is good when the amount of ink at the time of printing is small, but when the amount of ink increases, the ink is not completely absorbed and the image quality deteriorates, Problems such as delay in drying are likely to occur.

  In the porous layer having ink holding ability, the void volume with respect to the solid content volume is referred to as the porosity. In the present invention, it is preferable to set the porosity to 50% or more because the voids can be efficiently formed without unnecessarily increasing the film thickness.

  As another type of void type, in addition to forming an ink absorbing layer using inorganic fine particles, a polyurethane resin emulsion, a water-soluble epoxy compound and / or an acetoacetylated polyvinyl alcohol, and an epichlorohydrin polyamide resin are used in combination. The ink absorbing layer may be formed using the applied coating liquid. The polyurethane resin emulsion in this case is preferably a polyurethane resin emulsion having a polycarbonate chain, a polycarbonate chain and a polyester chain and a particle diameter 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. Further, the polyurethane resin obtained by reacting the aliphatic isocyanate compound with sulfonic acid group in the molecule further has epichlorohydrin polyamide resin and water-soluble epoxy compound and / or acetoacetylated vinyl alcohol. preferable. The ink absorbing layer using the polyurethane resin is presumed that a weak aggregation of cations and anions is formed, and accordingly, voids having an ink solvent absorbing ability are formed, so that an image can be formed.

  In the present invention, it is preferable to use a curing agent. The curing agent can be added at any time during the production of the ink jet recording paper. For example, the curing agent may be added to the coating liquid for forming the ink absorbing layer.

  In the present invention, a method of supplying a water-soluble binder curing agent after forming the ink absorbing layer may be used alone, but preferably, the above-described curing agent is added to the coating liquid for forming the ink absorbing layer. It is to be used in combination with the method.

  The curing agent that can be used in the present invention is not particularly limited as long as it causes a curing reaction with a water-soluble binder, but boric acid and its salts are preferable, but other known ones can be used. Specifically, it is a compound having a group capable of reacting with a water-soluble binder or a compound that promotes the reaction between different groups of the water-soluble binder, and is appropriately selected according to the type of the water-soluble binder. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl- 4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glioxal, etc.), active halogen curing agents (2,4-dichloro-4-hydroxy-1,3,5) -S-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

  Boric acid or a salt thereof refers to an oxygen acid having a bo atom as a central atom and a salt thereof. Specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, and octaboron. Examples include acids and their salts.

  Boric acid having a boron atom as a curing agent and a salt thereof may be used alone or in a mixture of two or more. Particularly preferred is a mixed aqueous solution of boric acid and borax.

  The aqueous solutions of boric acid and borax can be added only in relatively dilute aqueous solutions, respectively, but by mixing both, a concentrated aqueous solution can be obtained and the coating solution can be concentrated. Further, there is an advantage that the pH of the aqueous solution to be added can be controlled relatively freely. The total amount of the curing agent used is preferably 1 to 600 mg per 1 g of the water-soluble binder.

  Various additives other than those described above can be used for the ink absorbing layer of the recording paper according to the present invention and other layers provided as necessary. For example, organic latex fine particles such as polystyrene, polyacrylic acid esters, polymethacrylic acid esters, polyacrylamides, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, or a copolymer thereof, urea resin, or melamine resin , Anionic, cationic, nonionic, betaine type surfactants, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192 No. 57-87989, No. 60-72785, No. 61-146591, No. 1-95091 and No. 3-13376, etc., No. 59-42993, 59-52689, 62-280069, 61-242871 and JP-A-4 209266, etc., optical brighteners, sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents, preservatives, thickeners, antistatic agents Various known additives such as an agent and a matting agent can also be contained.

  The ink absorbing layer may be composed of two or more layers. In this case, the structures of the ink absorbing layers may be the same or different from each other.

The porous layer as described above is particularly preferably used in the ink jet recording method. The void volume of the porous layer preferable for the ink jet recording method is 10 to 30 ml / m ² .

  The coating layer in the recording paper of the present invention can be applied by a conventionally known coating method, for example, gravure coating method, roll coating method, rod bar coating method, air knife coating method, spray coating method, extrusion coating. A method, a slide bead coating method, a curtain coating method, a slot nozzle spray coating method, or an extrusion coating method using a hopper described in US Pat. No. 2,681,294 is preferably used.

  Various additives can be used for each layer of the recording paper according to the present invention. For example, organic latex fine particles such as polystyrene, polyacrylic acid esters, polymethacrylic acid esters, polyacrylamides, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, or a copolymer thereof, urea resin, or melamine resin , Anionic, cationic, nonionic, betaine type surfactants, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192 No. 57-87989, No. 60-72785, No. 61-146591, No. 1-95091 and No. 3-13376, etc., No. 59-42993, 59-52689, 62-280069, 61-242871 and JP-A-4 209266, etc., optical brighteners, sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents, preservatives, thickeners, antistatic agents Various known additives such as an agent and a matting agent can also be contained.

  As the support that can be used in the present invention, those conventionally known for inkjet recording paper can be used as appropriate, and may be a water-absorbing support, but is preferably a non-water-absorbing support. That is, in the case of the non-water-absorbing support, a larger amount of the water-soluble organic solvent in the pigment ink remains in the recording paper than in the case of the water-absorbing support, and acts more effectively on dissolution of organic fine particles. Therefore, it is estimated that the effect of the present invention can be remarkably exhibited. To be precise, it is preferable to use “a support that does not absorb the water-soluble organic solvent in the ink”, but here, even if a non-water-absorbing support is used, the effect of the present invention is remarkably exhibited. I think we can do it.

  Examples of the water-absorbing support that can be used in the present invention include sheets and plates having general paper, cloth, wood, and the like. In particular, paper is excellent in water absorption of the substrate itself and It is most preferable because of its excellent cost. The paper support can be made from chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, CGP, RMP, TMP, CTMP, CMP and PGW, and wood pulp such as waste paper pulp such as DIP. It is. Further, various fibrous materials such as synthetic pulp, synthetic fibers, inorganic fibers and the like can be appropriately used as raw materials as necessary.

  If necessary, various conventionally known additives such as sizing agents, pigments, paper strength enhancers, fixing agents, fluorescent whitening agents, wet paper strength agents, cationizing agents and the like are added to the paper support. I can do it.

  The paper support can be produced with various paper machines such as a long net paper machine, a circular net paper machine, and a twin wire paper machine by mixing the above-mentioned fibrous material such as wood pulp and various additives. If necessary, the paper can be subjected to size press treatment with starch, polyvinyl alcohol or the like, various coating treatments, or calendar treatment on the paper making stage or paper machine.

  Non-water-absorbing supports that can be preferably used in the present invention include transparent supports and opaque supports. Examples of the transparent support include films having materials such as polyester resins, diacetate resins, triatesate resins, acrylic resins, polycarbonate resins, polyvinyl chloride resins, polyimide resins, cellophane, and celluloid. Among them, those having a property of withstanding radiant heat when used for overhead projectors (OHP) are preferable, and polyethylene terephthalate is particularly preferable. The thickness of such a transparent support is preferably 50 to 200 μm.

  Further, as the opaque support, for example, a resin-coated paper (so-called RC paper) having a polyolefin resin coating layer in which a white pigment is added to at least one of the base paper, a white pigment such as barium sulfate is added to polyethylene terephthalate. A so-called white pet is preferable.

  For the purpose of increasing the adhesive strength between the various supports and the ink absorbing layer, the support is preferably subjected to corona discharge treatment, subbing treatment or the like prior to application of the ink absorbing layer. Further, the recording paper according to the present invention is not necessarily colorless, and may be a colored recording sheet.

  In the recording paper according to the present invention, it is possible to use a paper support obtained by laminating both sides of a base paper support described in Japanese Patent Application Laid-Open No. 2004-122705 with polyethylene. This is particularly preferable because an image of

  Examples of the coating method include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or an extrusion coating method using a hopper described in US Pat. No. 2,681,294. Preferably used. The ink absorbing layer is preferably composed of a porous layer described in JP-A-2004-122705.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples. In Examples, “%” indicates mass% unless otherwise specified.

Example 1
Recording paper was produced using the coating production line shown in FIG.

<Preparation of a belt-like support coated with a porous ink absorbing layer>
(Preparation of dispersion)
To 100 g of a 15% aqueous solution of cationic polymer (P1), 500 g of a 25% aqueous dispersion of fine particle silica (manufactured by Tokuyama, QS-20) having an average primary particle size of 12 μm, then 3.0 g of boric acid, 0% of borax 0.7 g was added and dispersed with a high-speed homogenizer to obtain a clear blue-white dispersion.

(Preparation of coating solution)
The prepared dispersion was heated to 45 ° C., and a 10% aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA203) and a 6% aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA245) were each heated to 45 ° C. and then added. Subsequently, 45 degreeC pure water was added and the liquid quantity was adjusted, and the translucent coating liquid was obtained.

(Application)
On a paper support (width 1500 mm, thickness 230 μm) coated on both sides with polyethylene, the above coating solution was applied and dried using a slide bead-type coating machine, and a belt-like support 15 coated with a porous ink absorbing layer was obtained. 1,000 m was produced. The coating speed was 200 m / min. The amount of each component in the lower layer of the belt-like support coated with the porous ink absorbing layer is as follows, and the dry film thickness is 35 μm.

Fine silica 15g / m ²
Cationic polymer (P1) 2.2 g / m ²
Polyvinyl alcohol 2.3 g / m ²
After coating the ink absorbing layer coating liquid, the film surface temperature is lowered to 10 ° C. or lower by passing through a cooling zone maintained at 10 ° C. for 15 seconds, and then the air at the following temperature is sequentially applied to the surface of the ink absorbing layer. While being sprayed, each zone of the drying process was passed through and dried.

  Note that the total drying process in the first drying section was 360 seconds, of which the average relative humidity of the blowing air was 30% or less for the first 270 seconds. After 270 seconds, the humidity was adjusted to a relative humidity of 40 to 60%.

<Preparation of spray application device>
A spray coater, coating solution scattering prevention means, and monitoring means constituting the spray coating apparatus shown below were prepared.
(Preparation of spray coater)
The spray coater shown in FIGS. 5 to 7 was prepared. The prepared spray coater had a coating width of 1470 mm, a gap width of the coating liquid nozzle of 60 μm, and a gap width of the air nozzle of 200 μm. The angle of the air nozzle with respect to the coating solution nozzle was 40 deg. The comb-shaped member shown in FIG. 7 is sandwiched between the coating solution nozzles, and the comb blade pitch (interval) is 500 μm. The crossing angle between the spray coater and the support was 90 °.
(Preparation of coating solution splash prevention means)
As shown in Table 1, coating liquid scattering prevention means shown in FIGS. 3 and 4 with the opening area changed were prepared and designated as 1-a to 1-f. The length of the current plate (ratio to the height of the opening (%)) is 80%, and the mounting position of the current plate (distance from the upper end of the main body of the coating liquid splash prevention means to the mounting position of the current plate) The thickness of the rectifying plate was 5 mm. Acrylic resin was used for the main body and the current plate of the coating liquid scattering prevention means. A polyacrylamide-based adsorbing member was attached to the upper side of the main body of the coating solution scattering prevention means. In addition, the area of an opening part shows the ratio (%) with respect to a spraying area.

(Preparation of monitoring means)
As a monitoring means, a high-speed video camera (manufactured by PHOTORON) was used.

[Application of surface layer]
When the drying reduction of the dry ink absorption layer in the drying section shown in FIG. 1 is completed, the spray coating device shown in FIGS. 2 to 6 is used to form the spray port of the spray coater as shown in FIG. The lines were arranged so as to be parallel to the support and at an angle of 90 ° intersecting the direction of travel of the support. The prepared coating liquid scattering prevention means No. The amount of gas sucked by the suction means 1-a to 1-f is changed as shown in Table 2, and the coating liquid for the surface layer is prepared so as to have a wet film thickness of 15 μm. And a recording material having a surface layer was dried to prepare a sample no. 101-130. In addition, the whole drying process after spray-coating was made into 100 second, and the wind with a relative humidity of 40-60% was sprayed. The coating solution was filtered using a filter having a caliber of 1/20 with respect to a width of 60 μm between the coating solution nozzles. The air used was filtered using a filter having a 1/50 aperture for the air nozzle gap width of 200 μm.

  The amount of air supplied from the air nozzle was 18 CMM / m (flow rate per coating width), and the internal pressure at the air nozzle at that time was 10 kPa. The linear velocity v of air was 150 m / s. The gap between the spray port of the spray coater and the ink absorbing layer was 20 mm, and the coating speed was 200 m / sec. The gas suction amount indicates a ratio (%) to the air supply amount of the spray coater.

<Preparation of coating solution for surface layer>
A coating solution having the following composition was prepared.

160 ml of polyaluminum chloride
(Taki Chemical Co., Ltd. PAC250A, solid content 23.5%)
840 ml of water
The viscosity at 25 ° C. was 0.9 mPa as a result of measurement with a B-type viscometer. The surface tension was adjusted with a surfactant so as to be 40 mN / m.

(Evaluation)
Each prepared sample No. Table 2 shows the results obtained by visually observing the coating yield and coating unevenness from 101 to 130, from the start of coating to the end of coating, and according to the following evaluation rank. The coating yield was determined by actual measurement concentration / theoretical concentration × 100, and evaluated according to the following evaluation rank. The measured concentration was measured at 10 points in the width direction at intervals of 10 m from the start of application to the end of application of each sample, and an average value was obtained from all measured values. The theoretical concentration was obtained by preparing a calibration curve in which the relationship between the coating film thickness and the concentration was known in advance.

Evaluation rank of coating yield ○: Coating yield is 98 to 100%
Δ: Application yield is less than 95 to 98% ×: Application yield is less than 95% Evaluation rank of application unevenness ○: No application unevenness is observed on the application surface Δ: Application which is practically acceptable on the application surface Unevenness is recognized ×: The coating unevenness is strong and it is impossible to produce a product

  Sample No. produced using a spray coating apparatus having an opening area of less than 100%. In the case of 101 to 105, the flow rate at the time of gas suction becomes higher than necessary, and the air flow between the spray coater and the support becomes turbulent, spraying is not performed uniformly, and the coating yield is reduced. Further, the occurrence of coating unevenness was confirmed.

  Sample No. produced using a spray coating apparatus having an opening area exceeding 700%. In the case of 126 to 130, the gas suction pressure for preventing the coating liquid from scattering must be sucked at a pressure higher than the tension of the support acting on the backup roll. The occurrence of coating unevenness was confirmed. In addition, a part of the sprayed droplets of the coating liquid was sucked before reaching the support and rubbed, the coating amount on the support was reduced, and it was confirmed that the coating yield was lowered.

  Sample No. produced by setting the gas suction amount of the suction means to 90% with respect to the gas supply amount of the spray coater. In Nos. 101, 106, 111, 116, 121, and 126, a spray-like coating liquid that is not used for coating adheres to the inside of the coating liquid scattering prevention means, drops into droplets, and uneven coating occurs. In addition, some of the sprayed droplets of the coating liquid are scattered before reaching the support and rubbed, and uniform spraying cannot be performed, uneven coating occurs, and the amount applied to the support decreases. A decrease in coating yield was confirmed. Sample No. produced by setting the gas suction amount of the suction means to 310% with respect to the gas supply amount of the spray coater. No. 105, 110, 115, 120, 125, 130 has uneven coating because the sprayed coating liquid is disturbed by the gas flow inside the coating liquid scattering prevention means and cannot be stably applied to the support. did. In addition, a part of the sprayed droplets of the coating liquid was sucked before reaching the support and rubbed, the coating amount on the support was reduced, and it was confirmed that the coating yield was lowered.

  Further, when visually observing the sample, the failure occurrence location was read in advance based on the information from the monitoring means, and as a result of observation, it was confirmed that the information from the monitoring means coincided with the position of the failure location visually. The application yield is obtained by setting the area of the opening of the coating liquid scattering prevention means to 100 to 700% with respect to the spray area and the gas suction amount of the suction means to 100 to 300% with respect to the gas supply amount of the spray coater. The effectiveness of the present invention was confirmed by confirming the reliability of the monitoring means and the ability to perform stable coating without the occurrence of a decrease in the thickness and the occurrence of coating unevenness.

Example 2
<Preparation of a belt-like support coated with a porous ink absorbing layer>
The same method as in Example 1 was used.

<Preparation of spray application device>
A spray coater, coating solution scattering prevention means, and monitoring means constituting the spray coating apparatus shown below were prepared.

(Preparation of spray coater)
The same spray coater as in Example 1 was prepared.

(Preparation of coating solution splash prevention means)
As shown in Table 3, the coating liquid scattering prevention means shown in FIGS. 2-a to 2-e. The area of the opening (ratio to the spray area (%)) is 300%, and the mounting position of the rectifying plate (distance from the upper end of the main body of the coating liquid splash prevention means to the mounting position of the rectifying plate) is 10 mm. The thickness of the rectifying plate was 5 mm. Acrylic resin was used for the main body and the current plate of the coating liquid scattering prevention means. A polyacrylamide-based adsorbing member was attached to the upper side of the main body of the coating solution scattering prevention means.

(Preparation of monitoring means)
The same thing as Example 1 was prepared.

[Application of surface layer]
When the drying reduction of the dry ink absorption layer in the drying section shown in FIG. 1 is completed, the spray coating device shown in FIGS. 2 to 6 is used to form the spray port of the spray coater as shown in FIG. The lines were arranged so as to be parallel to the support and at an angle of 90 ° intersecting the direction of travel of the support. The prepared coating liquid scattering prevention means No. Recordings having a surface layer were applied by applying the coating solution for the surface layer under the same conditions as in Example 1 except that the amount of gas suction by the suction means 2-a to 2-f was changed as shown in Table 4. A material was prepared and sample no. 201-225. The gas suction amount indicates a ratio (%) to the air supply amount of the spray coater. The amount of gas supplied from the gas supply means of the coating liquid scattering prevention means was 3.5 m ³ / min. The coating solution for the surface layer was the same as that used in Example 1 with a dye added and colored.

(Evaluation)
Each prepared sample No. Table 4 shows the results of evaluations on application unevenness and application yield. The coating unevenness and the coating yield were visually determined from the start of coating to the end of coating, and evaluated according to the same evaluation rank as in Example 1.

  Sample No. produced with the area of the opening being 300% of the spray area and the gas suction amount of the suction means being 90% with respect to the gas supply amount of the spray coater. In 201, 206, 211, 216, 221, and 226, a spray-like coating liquid that is not used for coating adheres to the inside of the coating liquid scattering prevention means, drops into droplets, and uneven coating occurs.

  Sample No. produced with the area of the opening being 300% with respect to the spray area and the gas suction amount of the suction means being 310% with respect to the gas supply amount of the spray coater. In 205, 210, 215, 220, 225, and 230, the sprayed coating liquid is disturbed by the flow of gas inside the coating liquid scattering prevention means and cannot be stably applied to the support. did. In addition, the sprayed coating liquid droplets were unnecessarily sucked into the coating liquid scattering prevention means, and the coating rate on the support decreased, resulting in a decrease in coating yield. When the length of the rectifying plate inside the coating liquid scattering prevention means is shortened, the sprayed coating liquid tends to be sucked faster and the coating rate tends to decrease. Also, if the length of the rectifying plate inside the coating liquid scattering prevention means is increased, the gas flow at the tip of the rectifying plate becomes faster and the sprayed coating liquid tends to be disturbed, and uneven coating tends to occur. It was confirmed that Further, when visually observing the sample, the failure occurrence location was read in advance based on the information from the monitoring means, and as a result of observation, it was confirmed that the information from the monitoring means coincided with the position of the failure location visually.

  The area of the opening of the coating liquid scattering prevention means is within the scope of the present invention, the gas suction amount of the suction means is set to 100 to 300% with respect to the gas supply amount of the spray coater, the length of the rectifying plate, the mounting position and the rectification The thickness of the plate is within the preferable range of the present invention, and by using the monitoring means, it is confirmed that the coating yield can be reduced, stable coating without occurrence of uneven coating and the reliability of the monitoring means can be confirmed. Thus, the effectiveness of the present invention was confirmed.

Example 3
<Preparation of a belt-like support coated with a porous ink absorbing layer>
The same method as in Example 1 was used.

<Preparation of spray application device>
A spray coater, coating solution scattering prevention means, and monitoring means constituting the spray coating apparatus shown below were prepared.

(Preparation of spray coater)
The same spray coater as in Example 1 was prepared.

(Preparation of coating solution splash prevention means)
As shown in Table 5, the coating liquid scattering prevention means shown in FIGS. 3 and 4 is prepared in which the mounting position of the current plate (the distance from the upper end of the main body of the coating liquid scattering prevention means to the mounting position of the current plate) is changed. No. 3-a to 3-e. The area of the opening (ratio to the spray area (%)) is 300%, the length of the current plate (ratio to the height of the opening (%)) is 60%, and the thickness of the current plate is 5 mm. . Acrylic resin was used for the main body and the current plate of the coating liquid scattering prevention means. A polyacrylamide-based adsorbing member was attached to the upper side of the main body of the coating solution scattering prevention means.

(Preparation of monitoring means)
The same thing as Example 1 was prepared.

[Application of surface layer]
When the drying reduction of the dry ink absorption layer in the drying section shown in FIG. 1 is completed, the spray coating device shown in FIGS. 2 to 6 is used to form the spray port of the spray coater as shown in FIG. The lines were arranged so as to be parallel to the support and at an angle of 90 ° intersecting the direction of travel of the support. The prepared coating liquid scattering prevention means No. The recording material having the surface layer was applied by applying the coating liquid for the surface layer under the same conditions as in the examples except that the gas suction amount by the suction means of 3-a to 3-f was changed as shown in Table 6. And sample no. 301 to 330. The gas suction amount indicates a ratio (%) to the air supply amount of the spray coater.

(Evaluation)
Each prepared sample No. Table 6 shows the results of visual evaluations according to the same evaluation rank as in Example 1, with reference to 301 to 330, and visual judgment on coating yield and coating unevenness accompanying dropping of droplets.

  Sample No. produced with the area of the opening being 300% of the spray area and the gas suction amount of the suction means being 90% with respect to the gas supply amount of the spray coater. In 301, 306, 311, 316, 321, and 326, a spray-like coating liquid that is not used for coating adheres to the inside of the coating liquid scattering prevention means, drops into droplets, and uneven coating occurs.

  Sample No. produced with the area of the opening being 300% with respect to the spray area and the gas suction amount of the suction means being 310% with respect to the gas supply amount of the spray coater. In 305, 310, 315, 320, 325, and 330, the sprayed coating liquid is disturbed by the flow of gas inside the coating liquid scattering prevention means and cannot be stably applied to the support. did. Further, it was confirmed that the coating yield was lowered because the sprayed coating liquid droplets were sucked to the coating liquid scattering prevention means more than necessary, and the coating rate on the support decreased. Further, when visually observing the sample, the failure occurrence location was read in advance based on the information from the monitoring means, and as a result of observation, it was confirmed that the information from the monitoring means coincided with the position of the failure location visually.

  The area of the opening of the coating liquid scattering prevention means is within the scope of the present invention, the gas suction amount of the suction means is set to 100 to 300% with respect to the gas supply amount of the spray coater, the length of the rectifying plate, the mounting position and the rectification The thickness of the plate is within the preferable range of the present invention, and by using the monitoring means, it is confirmed that the coating yield can be reduced, stable coating without occurrence of uneven coating and the reliability of the monitoring means can be confirmed. Thus, the effectiveness of the present invention was confirmed.

Example 4
<Preparation of a belt-like support coated with a porous ink absorbing layer>
The same method as in Example 1 was used.

<Preparation of spray application device>
A spray coater, coating solution scattering prevention means, and monitoring means constituting the spray coating apparatus shown below were prepared.

(Preparation of spray coater)
The same spray coater as in Example 1 was prepared.

(Preparation of coating solution splash prevention means)
As shown in Table 7, the coating liquid scattering prevention means shown in FIGS. 4-a to 4-e. The area of the opening (ratio to the spray area (%)) is 300%, the length of the rectifying plate (ratio to the height of the opening (%)) is 80%, and the position of the rectifying plate is attached (spray of coating liquid) The distance from the upper end of the main body of the prevention means to the mounting position of the current plate is 10 mm. Acrylic resin was used for the main body and the current plate of the coating liquid scattering prevention means. A polyacrylamide-based adsorbing member was attached to the upper side of the main body of the coating solution scattering prevention means.

(Preparation of monitoring means)
The same thing as Example 1 was prepared.

[Application of surface layer]
When the drying reduction of the dry ink absorption layer in the drying section shown in FIG. 1 is completed, the spray coating device shown in FIGS. 2 to 6 is used to form the spray port of the spray coater as shown in FIG. The lines were arranged so as to be parallel to the support and at an angle of 90 ° intersecting the direction of travel of the support. The prepared coating liquid scattering prevention means No. The recording material having the surface layer was applied by applying the coating liquid for the surface layer under the same conditions as in the examples except that the gas suction amount by the suction means of 4-a to 4-fe was changed as shown in Table 8. And sample no. 401 to 430. The gas suction amount indicates a ratio (%) to the air supply amount of the spray coater.

(Evaluation)
Each prepared sample No. Table 8 shows the results of evaluations according to the same evaluation rank as in Example 1, in which the visual evaluation is performed according to the same evaluation rank as in Example 1.

  Sample No. produced with the area of the opening being 300% of the spray area and the gas suction amount of the suction means being 90% with respect to the gas supply amount of the spray coater. In Nos. 401, 406, 411, 416, 421, and 426, a spray-like coating liquid that is not used for coating adheres to the inside of the coating liquid scattering prevention means, drops into droplets, and uneven coating occurs.

  Sample No. produced with the area of the opening being 300% with respect to the spray area and the gas suction amount of the suction means being 310% with respect to the gas supply amount of the spray coater. In 405, 410, 415, 420, 425, 430, the sprayed coating liquid is disturbed by the flow of gas inside the coating liquid scattering prevention means and cannot be stably applied to the support. did. Further, it was confirmed that the coating yield was lowered because the sprayed coating liquid droplets were sucked to the coating liquid scattering prevention means more than necessary, and the coating rate on the support decreased. Further, when visually observing the sample, the failure occurrence location was read in advance based on the information from the monitoring means, and as a result of observation, it was confirmed that the information from the monitoring means coincided with the position of the failure location visually.

  The area of the opening of the coating liquid scattering prevention means is within the scope of the present invention, the gas suction amount of the suction means is set to 100 to 300% with respect to the gas supply amount of the spray coater, the length of the rectifying plate, the mounting position and the rectification The thickness of the plate is within the preferable range of the present invention, and by using the monitoring means, it is confirmed that the coating yield can be reduced, stable coating without occurrence of uneven coating and the reliability of the monitoring means can be confirmed. Thus, the effectiveness of the present invention was confirmed.

It is a schematic diagram which shows an example of the coating production line of the recording paper which has arrange | positioned the spray coating device. It is an expansion schematic plan view of the part shown by X of FIG. It is a schematic enlarged view of the part shown by X of FIG. FIG. 4 is an enlarged schematic view of a portion indicated by Y in FIG. 3. FIG. 2 is an enlarged schematic view showing a coating state of the spray coater shown in FIG. 1. FIG. 4 is an enlarged schematic view of a portion indicated by Z in FIG. 3. FIG. 7 is a schematic exploded perspective view of the spray coater shown in FIGS. 1 to 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating production line 2 Feeding part 201 Support body 203 Ink absorption layer 204 Surface layer 3 1st coating part 4 Cooling part 5 Drying part 6 2nd coating part 601 Spray coating apparatus 602 Spray coater 603 Coating liquid scattering prevention means 603a Opening Part 603f Adsorption member 604 Monitoring means 605 Backup roll 607 Gas supply means 608 Current plate 7 Winding part L Height M Length N Distance O Thickness

Claims (13)

On the at least one ink absorbing layer formed on the support that is supported by the backup roll and continuously conveyed, a spray coating device disposed at a position intersecting the conveying direction of the support is used to form the ink absorbing layer. In the spray coating method of the surface layer of the ink jet recording paper, the surface layer is formed by spray coating the coating liquid over the entire width in the width direction.
The spray coating device is disposed outside the drying process, and includes a spray coater, a monitoring unit, and a coating liquid scattering preventing unit.
The coating liquid scattering prevention means includes a box-structured main body having an opening on the spray coater side, suction means connected to the main body, recovery means, and a support having an ink absorption layer on the backup roll; Gas supply means for supplying gas to a gap with the lower surface of the main body, the spray coater so that the opening is brought into contact with the wall surface in the width direction of the spray coater and is close to the outer peripheral surface of the backup roll Are disposed either on the downstream side or on the upstream side of
The area of the opening is 100 to 700% with respect to the spray area,
The spray application method is characterized in that a gas suction amount of the suction means is 100 to 300% with respect to a gas supply amount of the spray coater. 2. The spray coating method according to claim 1, wherein a rectifying means is disposed inside the main body. 3. The monitoring device according to claim 1, wherein the monitoring unit is disposed at a position facing the coating liquid scattering preventing unit, constantly monitoring a spray state of the spray coater, and feeding back an abnormal application point to an application record. Spray application method. The said coating liquid scattering prevention means moves to the arrangement | positioning position from a standby position according to the movement from the standby position of a spray coater to an application position, The any one of Claims 1-3 characterized by the above-mentioned. Spray application method. The spray coating method for a surface layer according to any one of claims 1 to 4, wherein the spray coater is a curtain spray coater. The spray coating method according to claim 1, wherein the ink absorption layer is composed of a porous layer containing at least one inorganic fine particle and a binder. In a spray coating apparatus for coating a surface layer of inkjet recording paper, a coating layer is spray-coated on at least one ink absorbing layer formed on a support that is supported by a backup roll and continuously conveyed. ,
A spray coater, a monitoring unit, and a coating solution scattering prevention unit, disposed outside the drying process,
The coating liquid scattering prevention means includes a box-structured main body having an opening on the spray coater side, suction means connected to the main body, recovery means, and a support having an ink absorption layer on the backup roll; Gas supply means for supplying gas to a gap with the lower surface of the main body, the spray coater so that the opening is brought into contact with the wall surface in the width direction of the spray coater and is close to the outer peripheral surface of the backup roll Are disposed either on the downstream side or on the upstream side of
The area of the opening is 100 to 700% with respect to the spray area,
The spray coating apparatus is characterized in that a gas suction amount of the suction means is 100 to 300% with respect to an air supply amount of the spray coater. The spray coating apparatus according to claim 7, wherein a rectifying means is disposed inside the main body. 9. The monitoring device according to claim 7 or 8, wherein the monitoring means is disposed at a position facing the coating liquid scattering preventing means, constantly monitoring the spray state of the spray coater, and feeding back the abnormal application location to the application record. Spray application equipment. The said coating liquid scattering prevention means moves to the arrangement | positioning position from a standby position according to the movement from the standby position of a spray coater to an application position, The any one of Claims 7-9 characterized by the above-mentioned. Spray application device. 11. The surface layer spray coating apparatus according to claim 7, wherein the spray coater is a curtain spray coater. The spray coating apparatus according to claim 7, wherein the ink absorption layer is composed of a porous layer containing at least one inorganic fine particle and a binder. An ink jet recording paper produced by the surface layer spray coating method according to claim 1.

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