JP6317664B2 - Inkjet printing apparatus, inkjet printing method, and inkjet printing system - Google Patents

Description

  The present invention relates to an inkjet printing apparatus, an inkjet printing method, and an inkjet printing system.

  A varnish coat is known as one of surface treatments for printed matter. Varnishing is a technology that coats the image surface of printed matter with varnish, and is intended to give gloss to the image surface to give a high-class feel to the printed matter and to improve the abrasion resistance and chemical resistance of the image surface. Done.

  Patent Document 1 describes a technique in which a varnish coater is incorporated in an ink jet printing apparatus and varnished on a printed matter in-line.

JP 2004-330570 A

  By the way, in an inkjet printing apparatus incorporating a varnish coater, both printing with a varnish coat and printing without a varnish coat are possible. When printing is carried out, there are drawbacks that blocking occurs, adhesion of the varnish decreases, and glossiness decreases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an ink jet printing apparatus, an ink jet printing method, and an ink jet printing system capable of outputting a high-quality printed matter with or without varnishing. And

  Means for achieving the above object are as follows.

  (1) A printing unit that prints an image on a paper by an inkjet method, and an ink drying unit that heats the image surface of the paper printed by the printing unit to dry the ink, and indicates the strength of drying. Acquires information about the ink drying area where the drying intensity can be adjusted and whether to varnish the image surface. Based on the acquired information, the drying intensity determines the drying intensity when the ink is dried in the ink drying area. An ink jet printing apparatus comprising: a determination unit; and an ink drying control unit that controls the ink drying unit, the ink drying control unit operating the ink drying unit with the drying intensity determined by the drying intensity determination unit.

  The inventor of the present application has found that the tendency of blocking changes depending on the strength of the drying strength when the ink is dried, and that the adhesion and gloss of the varnish change when varnished. According to this aspect, the drying strength when the ink is dried is determined according to the presence or absence of the varnish coat. Thereby, it is possible to output a high-quality printed matter with or without varnishing.

  (2) The ink jet printing apparatus according to (1), wherein the drying strength determination unit further acquires information on a varnish to be used and determines a drying strength when the ink drying unit dries the ink based on the acquired information. .

  The inventors of the present application have found that blocking, varnish adhesion, and gloss can be improved by changing the drying strength when the ink is dried according to the varnish used. According to this aspect, dry strength is determined according to the varnish to be used. Thereby, blocking can be prevented appropriately and the adhesiveness and glossiness of a varnish can be improved.

  Even if the varnishes are of the same type, the influence on blocking or the like is different if the brands are different, so it is preferable to determine the drying strength for each varnish having a different brand.

  (3) When the varnish used is an aqueous varnish or UV varnish, the dry strength without varnish coat is the first dry strength, and the dry strength when varnished with the aqueous varnish is the second dry strength, varnished with UV varnish. If the drying strength in the case of the third drying strength is the second drying strength, the second drying strength is higher than the first drying strength, and the third drying strength is higher than the first drying strength. The inkjet printing apparatus according to the above (2), which has a low dry strength.

  According to this aspect, the dry strength when there is no varnish coat is the first dry strength, the dry strength when varnished with an aqueous varnish is the second dry strength, and the dry strength when varnished with UV varnish is the third dry strength. Assuming that the strength is high, the second dry strength is a dry strength stronger than the first dry strength, and the third dry strength is a dry strength weaker than the first dry strength. That is, when varnishing with an aqueous varnish, the drying treatment is performed with a stronger drying strength than without varnishing, and when varnishing with UV varnish, the drying treatment is performed with a lower drying strength than without varnishing.

  In the case of an aqueous varnish, if the dry strength is not sufficient, the solvent in the ink is mixed into the aqueous varnish, causing an event that the surface of the varnish layer becomes sticky. This stickiness causes blocking. Therefore, when varnishing with an aqueous varnish, the drying strength is set stronger than when no varnish is applied, and the solvent in the ink is prevented from mixing into the aqueous varnish, thereby preventing the occurrence of blocking. However, even if the drying strength is set too high, power is consumed wastefully, so the drying strength is set within an appropriate range.

  On the other hand, in the case of UV varnish, if the drying strength is increased too much, the wax component in the ink is unevenly distributed on the ink surface, resulting in a phenomenon that the adhesion between the ink layer and the varnish layer is lowered. Therefore, in the case of UV varnish, the drying strength is set to be weaker than in the case of no varnish coating, thereby preventing the wax component from being unevenly distributed on the ink surface and ensuring the adhesion between the ink layer and the varnish layer. However, if the drying strength is lowered too much, the solvent in the ink will be mixed into the UV varnish, and the gloss of the varnish will decrease and blocking will occur during storage. Set.

  (4) When the varnish used is an aqueous varnish, the inkjet printing apparatus according to the above (1), wherein the dry strength when varnish coating is higher than the dry strength when there is no varnish coat.

  As described above, in the case of an aqueous varnish, if the dry strength is not sufficient, blocking is induced. According to this aspect, when the varnish is applied, the drying strength is set stronger than when the varnish is not applied. Thereby, generation | occurrence | production of blocking can be prevented in any case.

  (5) The ink jet printing apparatus according to (1), wherein when the varnish used is UV varnish, the drying strength when varnishing is weaker than the drying strength without varnishing.

  As described above, in the case of UV varnish, if the drying strength is increased too much, the adhesion of the varnish is lowered. According to this aspect, in the case of varnish coating, the drying strength is set weaker than in the case of no varnish coating. Thereby, the adhesiveness of a varnish is securable.

  (6) A varnish application unit that applies varnish to the image surface of the paper after the ink has been dried by the ink drying unit, a varnish post-processing unit that post-processes the varnish applied to the image surface by the varnish application unit, and an image Information on whether or not to varnish the surface is obtained, and based on the obtained information, information on whether or not to varnish the image surface is obtained, and information on whether or not the image surface is varnished is obtained. The inkjet printing apparatus according to (1), further comprising: a varnish post-processing control unit that controls the varnish post-processing unit.

  According to this aspect, a varnish application unit that applies varnish to the image surface of the paper after drying the ink, a varnish post-processing unit that post-processes the varnish applied to the image surface by the varnish application unit, A varnish application control unit that controls the application unit and a varnish post-processing control unit that controls the varnish post-processing unit are further provided. Thereby, the printed matter can be varnished inline. The varnish application control unit and the varnish post-processing control unit control the varnish application unit and the varnish post-processing unit based on information on whether or not to varnish the image surface. That is, only in the case of varnish coating, the varnish application section and the varnish post-processing section are operated to varnish the image surface of the paper after ink drying.

  (7) The varnish post-processing unit includes a varnish heating unit that heats the varnish applied to the image surface, and a UV irradiation unit that irradiates UV to the varnish applied to the image surface. Further, the inkjet printing apparatus according to (6), wherein information on a varnish to be used is acquired, and the varnish post-processing unit is controlled based on the acquired information.

  According to this aspect, the varnish post-processing unit includes a varnish heating unit that heats the varnish applied to the image surface, and a UV irradiation unit that irradiates UV to the varnish applied to the image surface. . Thereby, a varnish coat using an aqueous varnish and a varnish coat using a UV varnish can be selectively performed.

  (8) The inkjet printing apparatus according to (7), wherein the varnish post-processing control unit operates the varnish heating unit and the UV irradiation unit when the image surface is varnished with UV varnish.

  According to this aspect, when the image surface is varnished with UV varnish, the varnish heating unit and the UV irradiation unit are operated to perform post-processing after varnish application. In the case of varnish coating with UV varnish, the wax component unevenly distributed on the surface of the ink layer can be re-dissolved in the varnish layer by heating the surface of the image coated with the varnish after UV application and before UV irradiation. The wax component unevenly distributed on the surface of the layer can be removed. Thereby, the adhesiveness of a varnish can be improved.

  (9) The varnish heating unit is configured to be capable of adjusting the heating intensity indicating the degree of strength for heating the varnish, acquires information on the varnish to be used, and is applied to the image surface based on the acquired information. The heating intensity determination unit that determines the heating intensity when heating the varnish with the varnish heating unit is further provided, and the varnish post-processing control unit operates the varnish heating unit with the heating intensity determined by the heating intensity determination unit (7 ) Or (8) inkjet printing apparatus.

  According to this aspect, the varnish heating unit is configured to be able to adjust the heating intensity indicating the degree of strength with which the varnish is heated. The heating intensity of the varnish heating unit is determined by the heating intensity determination unit based on information on the varnish to be used. The varnish post-processing control unit operates the varnish heating unit with the heating intensity determined by the heating intensity determination unit, and performs post-processing after varnish application. This makes it possible to post-process appropriately applied varnish. In particular, in the case of UV varnish, the diffusion of the wax component unevenly distributed on the image surface to the varnish layer can be accelerated by heating so that the temperature of the image surface is equal to or higher than the melting point of the wax component contained in the ink. The wax component unevenly distributed on the surface of the ink layer can be removed. Thereby, the adhesiveness of a varnish can be improved more effectively.

  (10) An inkjet printing system comprising: the inkjet printing device according to any one of (1) to (5) above; and a varnish device that receives paper discharged from the inkjet printing device and varnishes the image surface. The varnish coating device obtains information on whether or not to varnish, and a varnish application unit that applies varnish to the image surface of the paper, a varnish post-processing unit that post-processes the varnish applied to the image surface by the varnish application unit, The varnish application control unit that controls the varnish application unit based on the acquired information, and the varnish post-processing control unit that acquires the information on whether or not to varnish and control the varnish post-processing unit based on the acquired information An inkjet printing system comprising:

  According to this aspect, the ink jet printing apparatus and the varnish coating apparatus are connected, and after printing, the varnish processing can be continuously performed. Varnishing is performed selectively. When there is no varnish coat, the paper discharged from the inkjet printing apparatus is passed through the varnish coat apparatus.

  (11) The varnish post-processing unit includes a varnish heating unit that heats the varnish applied to the image surface, and a UV irradiation unit that irradiates UV to the varnish applied to the image surface. Further, the inkjet printing system according to (10), wherein information on a varnish to be used is further acquired, and the varnish post-processing unit is controlled based on the acquired information.

  According to this aspect, in the varnish coating apparatus, the varnish post-processing unit includes a varnish heating unit that heats the varnish applied to the image surface, and a UV irradiation unit that irradiates UV to the varnish applied to the image surface. Configured. Thereby, a varnish coat using an aqueous varnish and a varnish coat using a UV varnish can be selectively performed.

  (12) The inkjet printing system according to (11), wherein the varnish post-processing control unit operates the varnish heating unit and the UV irradiation unit when the image surface is varnished with UV varnish.

  According to this aspect, when the image surface is varnished with UV varnish, the varnish heating unit and the UV irradiation unit are operated to perform post-processing after varnish application. Thereby, the adhesiveness of a varnish can be improved.

  (13) The varnish heating unit is configured to be capable of adjusting the heating intensity indicating the degree of strength for heating the varnish, acquires information on the varnish to be used, and is applied to the image surface based on the acquired information. The heating intensity determining unit that determines the heating intensity when heating the varnish with the varnish heating unit is further provided, and the varnish post-processing control unit operates the varnish heating unit with the heating intensity determined by the heating intensity determining unit (11) Or the inkjet printing system according to (12).

  According to this aspect, in the varnish coating apparatus, the varnish heating unit is configured to be able to adjust the heating intensity. The heating intensity is determined based on information on the varnish used. This makes it possible to post-process appropriately applied varnish. In particular, in the case of UV varnish, the diffusion of the wax component unevenly distributed on the image surface to the varnish layer can be accelerated by heating so that the temperature of the image surface is equal to or higher than the melting point of the wax component contained in the ink. The wax component unevenly distributed on the surface of the ink layer can be removed. Thereby, the adhesiveness of a varnish can be improved more effectively.

  (14) A printing process for printing an image on paper by an ink jet method, and an ink drying process for drying the ink by heating the paper on which the image is printed, and whether the image surface is varnished after the ink is dried An ink drying process in which a drying strength indicating a degree of strength to dry is determined based on information on whether or not to dry.

  According to this aspect, the drying strength when the ink is dried is determined according to the presence or absence of the varnish coat. Thereby, it is possible to output a high-quality printed matter with or without varnishing.

  (15) The ink jet printing method according to (14), wherein in the ink drying step, the drying strength is further determined based on information on a varnish to be used.

  According to this aspect, dry strength is determined according to the varnish to be used. Thereby, blocking can be prevented appropriately and the adhesiveness and glossiness of a varnish can be improved.

  (16) When the varnish used is an aqueous varnish or UV varnish, the dry strength when there is no varnish coat is the first dry strength, and the dry strength when varnished with the aqueous varnish is the second dry strength, varnished with UV varnish If the drying strength in the case of the third drying strength is the second drying strength, the second drying strength is higher than the first drying strength, and the third drying strength is higher than the first drying strength. The inkjet printing method according to the above (15), wherein the ink has a low dry strength.

  According to this aspect, the dry strength when there is no varnish coat is the first dry strength, the dry strength when varnished with an aqueous varnish is the second dry strength, and the dry strength when varnished with UV varnish is the third dry strength. Assuming that the strength is high, the second dry strength is a dry strength stronger than the first dry strength, and the third dry strength is a dry strength weaker than the first dry strength. That is, when varnishing with an aqueous varnish, the drying treatment is performed with a stronger drying strength than without varnishing, and when varnishing with UV varnish, the drying treatment is performed with a lower drying strength than without varnishing.

  (17) The inkjet printing method according to (14), wherein when the varnish to be used is an aqueous varnish, the drying strength when varnishing is higher than the drying strength when there is no varnish coating.

  According to this aspect, when varnishing with an aqueous varnish, the drying strength is set stronger than when no varnish is applied. Thereby, generation | occurrence | production of blocking can be prevented in any case.

  (18) The inkjet printing method according to (14), wherein when the varnish used is UV varnish, the drying strength when varnishing is weaker than the drying strength when there is no varnish coating.

  According to this aspect, when varnishing with UV varnish, the drying strength is set weaker than when no varnish is applied. Thereby, the adhesiveness of a varnish is securable.

  (19) In the case where the image surface is varnished with UV varnish, the varnish applied to the image surface is heated before irradiating the varnish applied to the image surface with UV, and the inkjet according to any one of (14) to (18) Printing method.

  According to this aspect, when the image surface is varnished with UV varnish, the image surface is heated after UV application and before UV irradiation. Thereby, the wax component unevenly distributed on the surface of the ink layer can be removed, and the adhesion of the varnish can be improved.

  According to the present invention, it is possible to output a high-quality printed matter whether or not varnished.

Overall configuration diagram showing an embodiment of an inkjet printing apparatus Schematic diagram of varnish coater Block diagram showing schematic configuration of control system of inkjet printing apparatus Block diagram of functions realized by computer Flowchart showing a processing procedure until printing is started by an inkjet printing apparatus Flow chart showing the processing procedure for printing without varnishing Flow chart showing the printing processing procedure when varnish coating System configuration diagram of inkjet printing system for varnish coating offline Schematic configuration diagram of the inkjet printing apparatus shown in FIG. The block diagram which shows schematic structure of the control system of the inkjet printing apparatus shown in FIG. Block diagram of functions realized by the computer of the inkjet printing apparatus shown in FIG. Schematic configuration diagram of the varnish coat apparatus shown in FIG. The block diagram which shows schematic structure of the control system of the varnish coat apparatus shown in FIG. Block diagram of functions realized by the computer of the varnish coat apparatus shown in FIG. System configuration diagram of an inkjet printing system for online varnishing Table showing experimental results when varnished inline Table showing experimental results when varnished inline Table showing experimental results for online varnishing Table showing experimental results for online varnishing Table showing experimental results when offline varnished Table showing experimental results when offline varnished Table showing the results of experiments when varnish coating was performed with the varnish heating intensity changed offline. Table showing the results of experiments when varnish coating was performed with the varnish heating intensity changed offline. Table showing the experimental results when varnished with varying varnish heating strength online Table showing the experimental results when varnished with varying varnish heating strength online

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
<< Overall configuration of inkjet printing apparatus >>
FIG. 1 is an overall configuration diagram illustrating an embodiment of an inkjet printing apparatus.

  The ink jet printing apparatus 1 is configured as a printing apparatus capable of varnish coating inline, and includes a paper feeding unit 10 that feeds a sheet P, which is a sheet, and a processing liquid application that applies a processing liquid to the printing surface of the paper P. Part 20, a treatment liquid drying part 30 for drying the treatment liquid applied to the paper P, a printing part 40 for printing an image on the paper P on which the treatment liquid has been dried by an inkjet method, and heating the printing surface of the paper P An ink drying unit 50 for drying the ink, a varnish application unit 60 for applying varnish to the image surface of the paper P on which the ink has been dried, and a varnish post-processing unit 70 for performing a post-treatment on the varnish applied to the paper P. And a stacking unit 80 that stacks the printed paper P.

  For example, general-purpose printing paper is used as the paper P, and the paper P is set in the paper feeding unit 10 in a paper bundle state. The general-purpose printing paper is not a so-called inkjet paper but a paper mainly composed of cellulose such as coated paper generally used in offset printing or the like.

<Paper Feeder>
The paper feeding unit 10 feeds paper sheets one by one. As shown in FIG. 1, the paper feeding unit 10 mainly includes a paper feeding device 11, a feeder board 12, and a paper feeding drum 13.

  The paper feeding device 11 feeds the paper P one by one. The sheets P are set on a sheet feeding table in a bundle of sheets, and are fed at regular intervals in order from the top.

  The feeder board 12 receives the paper P fed from the paper feeding device 11, transports the received paper P along a certain transport path, and delivers it to the paper feeding drum 13.

  The paper feed drum 13 receives the paper P from the feeder board 12, transports the received paper P along a certain transport path, and delivers it to the processing liquid coating drum 21. The paper feed drum 13 is conveyed by winding the paper P around the peripheral surface by gripping and rotating the front end of the paper P with a gripper provided on the peripheral surface.

<Processing liquid application part>
The processing liquid application unit 20 applies the processing liquid to the printing surface of the paper P. This treatment liquid is a liquid having a function of aggregating the color material components in the ink. By applying such a treatment liquid and printing, high-quality images can be printed even when general-purpose printing paper is used. As shown in FIG. 1, the treatment liquid application unit 20 includes a treatment liquid application drum 21 that conveys the paper P along a certain conveyance path, and a treatment liquid application device 22 that applies the treatment liquid to the paper P. Configured.

  The treatment liquid application drum 21 receives the paper P from the paper supply drum 13, conveys the received paper P along a certain conveyance path, and delivers it to the treatment liquid drying drum 31. The treatment liquid application drum 21 conveys the paper P while being wrapped around the peripheral surface by gripping and rotating the leading edge of the paper P with a gripper provided on the peripheral surface.

  The processing liquid coating device 22 applies the processing liquid to the printing surface of the paper P conveyed by the processing liquid coating drum 21. The treatment liquid application device 22 applies the treatment liquid with a roller. That is, the processing liquid is applied to the paper P by pressing an application roller having a processing liquid applied to the peripheral surface against the printing surface of the paper P. In addition, the coating method of the processing liquid coating apparatus 22 is not particularly limited. In addition, the processing liquid can be applied by a method such as an inkjet method or a spray method.

  The treatment liquid application unit 20 is configured as described above. The processing liquid is applied to the printing surface of the paper P by the processing liquid coating device 22 in the process of being conveyed by the processing liquid coating drum 21.

<Processing liquid drying section>
The treatment liquid drying unit 30 dries the treatment liquid applied to the paper P. As shown in FIG. 1, the treatment liquid drying unit 30 includes a treatment liquid drying drum 31 that conveys the sheet P along a certain conveyance path, a first sheet guide 32 that guides the conveyance of the sheet P, and the sheet P. And a dryer 33 that blows hot air toward.

  The treatment liquid drying drum 31 receives the paper P from the treatment liquid application drum 21, conveys the received paper P along a certain conveyance path, and delivers it to the printing drum 41. The treatment liquid drying drum 31 conveys the paper P along a certain conveyance path by gripping and rotating the front end of the paper P with a gripper provided on the peripheral surface.

  The first paper guide 32 is disposed along the transport path of the paper P by the treatment liquid drying drum 31 and guides the transport of the paper P. The paper P is conveyed while sliding on the first paper guide 32.

  The dryer 33 blows hot air onto the printing surface of the paper P conveyed by the treatment liquid drying drum 31 to heat the printing surface of the paper P coated with the treatment liquid. In order to heat the printing surface, the dryer 33 is disposed inside the treatment liquid drying drum 31. The dryer 33 includes, for example, a heat source such as a halogen heater or an IR heater (InfraRed: infrared), and a blowing unit such as a fan or a blower that blows air heated by the heat source. When the dryer 33 is composed of a heater and a fan, the heating intensity is adjusted according to the number of lighting of the heater and / or the lighting duty ratio.

  The treatment liquid drying unit 30 is configured as described above. Hot air from the dryer 33 is blown onto the printing surface of the paper P in the process of being conveyed by the treatment liquid drying drum 31. Thereby, the printing surface is heated, and the solvent component of the treatment liquid applied to the printing surface is removed by drying.

<Printing section>
The printing unit 40 prints an image on the printing surface of the paper P by an inkjet method. As shown in FIG. 1, the printing unit 40 includes a printing drum 41 that conveys a sheet P along a certain conveyance path, a sheet pressing roller 42, and cyan (C), magenta (M), yellow ( Y) and inkjet heads 43C, 43M, 43Y, and 43K that eject ink droplets of black (K), and a scanner 44 that reads an image recorded on the paper P.

  The printing drum 41 receives the paper P from the treatment liquid drying drum 31, transports the received paper P along a certain transport path, and delivers it to the first chain delivery 51. The printing drum 41 grips and rotates the front end of the paper P with a gripper provided on the peripheral surface, thereby winding and transporting the paper P around the peripheral surface.

  The paper pressing roller 42 presses the paper P against the peripheral surface of the printing drum 41 and closely contacts the peripheral surface of the printing drum 41.

  The inkjet heads 43C, 43M, 43Y, and 43K draw ink images by ejecting ink droplets toward the printing surface of the paper P conveyed by the printing drum 41. The inkjet heads 43C, 43M, 43Y, and 43K are constituted by line heads that can print on a single sheet P in a single pass. The inkjet heads 43C, 43M, 43Y, and 43K are arranged on the conveyance path of the paper P by the printing drum 41 at a constant interval, and the nozzle rows are arranged orthogonal to the conveyance direction of the paper P.

  The scanner 44 reads an image recorded on the printing surface of the paper P conveyed by the printing drum 41. The scanner 44 is disposed on the downstream side of the inkjet head 43K located on the most downstream side with respect to the direction of the paper P.

  The printing unit 40 is configured as described above. The paper P is ejected from the inkjet heads 43C, 43M, 43Y, and 43K in the process of being conveyed by the printing drum 41, and is ejected onto the printing surface, and a color image is recorded on the printing surface. The scanner 44 reads a printed image as necessary.

<Ink drying section>
The ink drying unit 50 heats the printed paper P to dry the ink. As shown in FIG. 1, the ink drying unit 50 includes a first chain delivery 51 that transports the paper P along a certain transport path, and a second paper guide that guides the paper P transported by the first chain delivery 51. 52 and a first heating device 53 as a heating means for heating the image surface of the paper P conveyed by the first chain delivery 51.

  The first chain delivery 51 receives the paper P from the printing drum 41, transports the received paper P along a predetermined transport path, and delivers it to the varnish application drum 61. The first chain delivery 51 includes a pair of endless chains that travel along a certain travel route, and grips the leading end of the paper P with a gripper spanned between the pair of chains, thereby holding the paper P at a certain level. Transport along the transport path.

  The second paper guide 52 guides the travel of the paper P conveyed by the first chain delivery 51. The second paper guide 52 has a hollow board shape and has a flat guide surface along the paper P conveyance path. The paper P is conveyed while sliding on the guide surface. The guide surface has a number of suction holes. The sheet P slides on the guide surface while being sucked from the suction hole. As a result, the sheet P can be conveyed while tension is applied.

  The first heating device 53 heats the image surface of the paper P conveyed by the first chain delivery 51 to dry the ink. The first heating device 53 is configured, for example, by arranging a plurality of rod-shaped heaters at regular intervals along the sheet conveyance direction. Each heater is disposed orthogonal to the conveyance direction of the paper P. For example, a halogen heater or an IR heater is used as the heater. In the first heating device 53, the drying intensity indicating the degree of strength to dry is adjusted by the number of lighting heaters and / or the lighting duty ratio.

  The ink drying unit 50 is configured as described above. As the paper P is conveyed by the first chain delivery 51, the image surface is heated by the first heating device 53 and the ink is dried.

<Varnish application part>
The varnish application unit 60 applies varnish to the image surface of the paper P after printing. As shown in FIG. 1, the varnish coating unit 60 includes a varnish coating drum 61 that transports the paper P along a certain transport path, and a varnish coater that coats the image surface of the paper P transported by the varnish coating drum 61. 90.

  The varnish application drum 61 receives the paper P from the first chain delivery 51, transports the received paper P along a certain transport path, and delivers it to the second chain delivery 71. The varnish application drum 61 conveys the paper P wound around the peripheral surface by gripping and rotating the leading end of the paper P with a gripper provided on the peripheral surface.

  FIG. 2 is a schematic configuration diagram of the varnish coater. The varnish coater 90 mainly includes a varnish tank 91, a pumping roller 92 that pumps up, a measuring blade 93, a first intermediate transfer roller 94, a second intermediate transfer roller 95, and a varnish application roller 96. Is done.

  The varnish tank 91 stores varnish. A varnish supply device (not shown) is connected to the varnish tank 91. Varnish is circulated and supplied from the varnish supply device to the varnish tank 91. In addition, when changing the kind of varnish to apply | coat, it is performed by changing the kind of varnish supplied from a varnish supply apparatus.

  The pumping roller 92 pumps the varnish from the varnish tank 91. A part of the pumping roller 92 is immersed in the varnish in the varnish tank 91. The pumping roller 92 rotates to cause the varnish to adhere to the peripheral surface and pump the varnish from the varnish tank 91.

  The measuring blade 93 adjusts the thickness of the varnish adhering to the peripheral surface of the pumping roller 92 by scraping off unnecessary varnish from the peripheral surface of the pumping roller 92. The thickness of the varnish applied to the paper P is adjusted by the measuring blade 93.

  The first intermediate transfer roller 94 and the second intermediate transfer roller 95 transfer the varnish pumped up by the pump-up roller 92 to the varnish application roller 96. The first intermediate transfer roller 94 is in contact with the pumping roller 92 and the second intermediate transfer roller 95, and the second intermediate transfer roller 95 is in contact with the first intermediate transfer roller 94 and the varnish application roller 96. The The varnish pumped up by the pump-up roller 92 is transferred to the first intermediate transfer roller 94 and transferred from the first intermediate transfer roller 94 to the peripheral surface of the varnish application roller 96 via the second intermediate transfer roller 95. .

  The first intermediate transfer roller 94 is provided so as to be swingable about the rotation axis of the pumping roller 92. The first intermediate transfer roller 94 is driven by an actuator (not shown) and moves between a contact position indicated by a solid line in FIG. 2 and a retracted position indicated by a broken line in FIG. The first intermediate transfer roller 94 contacts the peripheral surface of the second intermediate transfer roller 95 when moved to the contact position, and is separated from the peripheral surface of the second intermediate transfer roller 95 when moved to the retracted position. By controlling the movement of the first intermediate transfer roller 94, the supply of varnish to the varnish application roller 96 can be turned ON / OFF. That is, the supply of varnish and the supply stop can be controlled.

  The varnish application roller 96 applies varnish to the image surface of the paper P conveyed by the varnish application drum 61. The varnish application roller 96 is provided so as to be swingable about the rotation axis of the second intermediate transfer roller 95. The varnish application roller 96 is driven by an actuator (not shown) and moves between an application position indicated by a solid line in FIG. 2 and a separation position indicated by a broken line in FIG. The varnish application roller 96 is pressed and brought into contact with the peripheral surface of the varnish application drum 61 when moved to the application position, and is separated from the peripheral surface of the varnish application drum 61 when moved to the separation position. By controlling the movement of the varnish application roller 96, application of the varnish to the paper P can be turned ON / OFF. That is, application and non-application of varnish can be controlled.

  The varnish application unit 60 is configured as described above. When varnishing the paper P after printing, the varnish application roller 96 is pressed against the printing surface in the process of being conveyed to the varnish application drum 61, and the varnish is applied to the printing surface. When the printed paper P is not varnished, the paper P is passed through the varnish application unit 60. In this case, the varnish applying roller 96 is located at the separation position, and the first intermediate transfer roller 94 is located at the retracted position. As a result, the paper P is conveyed to the varnish application drum 61 without doing anything at the varnish application part 60.

<Variet aftertreatment>
The varnish post-processing unit 70 performs post-processing of the varnish applied to the image surface of the paper P by the varnish application unit 60. The content of the post-treatment varies depending on the type of varnish used. When the varnish to be used is an aqueous varnish, the post-treatment is a heat drying treatment. On the other hand, when the varnish to be used is UV varnish, the post-treatment is mainly UV curing treatment.

  The heat drying process is a process of heating the image surface of the paper P coated with varnish to dry the varnish, that is, a process of volatilizing moisture or a solvent in the varnish. Thereby, the stickiness of the surface of a varnish layer is suppressed and generation | occurrence | production of blocking is suppressed.

  The UV curing process is a process of irradiating the image surface of the paper P coated with the varnish with UV to cure the varnish.

  In the inkjet printing apparatus 1 of the present embodiment, the varnish post-processing section 70 is provided with a heating ability and a UV irradiation function so that the aqueous varnish and the UV varnish can be post-processed.

  The aqueous varnish is a water-soluble varnish, and the UV varnish is a varnish containing a material that is cured by UV (ultraviolet) irradiation.

  As illustrated in FIG. 1, the varnish post-processing unit 70 includes a second chain delivery 71 that transports the paper P along a certain transport path, and a third paper that guides the paper P transported by the second chain delivery 71. The guide 72, the varnish heating unit 70A for heating the image surface of the paper P conveyed by the second chain delivery 71 and drying the varnish applied to the image surface, and the paper P conveyed by the second chain delivery 71 A UV irradiation unit 70B that irradiates the image surface with UV and UV cures the varnish applied to the image surface.

  The second chain delivery 71 receives the paper P from the varnish application drum 61, transports the received paper P along a certain transport path, and discharges the paper at a paper discharge position. The second chain delivery 71 includes a pair of endless chains that travel along a certain travel route, and grips the leading edge of the paper P with a gripper spanned between the pair of chains, thereby holding the paper P at a certain level. Transport along the transport path.

  The third paper guide 72 guides the travel of the paper P conveyed by the second chain delivery 71. The third paper guide 72 has a hollow board shape and has a flat guide surface along the paper P conveyance path. The paper P is conveyed while sliding on the guide surface. The guide surface has a number of suction holes. The sheet P slides on the guide surface while being sucked from the suction hole. As a result, the sheet P can be conveyed while tension is applied.

  The varnish heating unit 70A heats the image surface of the paper P conveyed by the second chain delivery 71, and dries the varnish applied to the image surface. The varnish heating unit 70A includes a second heating device 73 as a heating unit for heating the image surface. The second heating device 73 is configured, for example, by arranging a plurality of rod-shaped heaters along the conveyance direction of the paper P. For example, a halogen heater or an IR heater is used as the heater. Each heater is disposed orthogonal to the conveyance direction of the paper P. In the second heating device 73, the heating intensity indicating the degree of strength with which the varnish is heated is adjusted according to the number of lighting heaters and / or the lighting duty ratio.

  The UV irradiation unit 70B irradiates the image surface of the paper P conveyed by the second chain delivery 71 with UV, and dries the varnish applied to the image surface. The UV irradiation unit 70B is disposed on the downstream side of the varnish heating unit 70A with respect to the conveyance direction of the paper P. The UV irradiation unit 70B includes a UV irradiation device 74 as UV irradiation means for irradiating the image surface with UV. The UV irradiation device 74 includes a plurality of UV lamps. The UV lamps are arranged at regular intervals along the transport path of the paper P.

  The varnish post-processing unit 70 is configured as described above. The sheet P coated with the aqueous varnish is heated by the second heating device 73 in the course of being conveyed by the second chain delivery 71, and the coated varnish is dried. The sheet P coated with the UV varnish is irradiated with UV on the image surface by the UV irradiation device 74 in the process of being conveyed by the second chain delivery 71, and the varnish is cured.

  In addition, also when apply | coating UV varnish, the varnish apply | coated by the 2nd heating apparatus 73 is heated as needed. That is, the varnished image surface is heated before UV irradiation. Thereby, the wax component unevenly distributed on the surface of the ink layer can be redissolved in the varnish layer, and the wax component unevenly distributed on the surface of the ink layer can be removed. Thereby, the adhesiveness of a varnish can be improved.

<Accumulation part>
The stacking unit 80 stacks the discharged paper P. The stacking unit 80 includes a stacking device 81. The stacking device 81 receives the paper P released from the second chain delivery 71 at a predetermined paper discharge position, and stacks and collects the paper P on the paper discharge table.

  The inkjet printing apparatus 1 is configured as described above. In the above configuration, the feeder board 12 of the paper feed unit 10, the paper feed drum 13, the treatment liquid application drum 21 of the treatment liquid application unit 20, the treatment liquid drying unit 30 of the treatment liquid drying unit 30, and the printing unit 40. The printing drum 41, the first chain delivery 51 of the ink drying unit 50, the varnish application drum 61 of the varnish application unit 60, and the second chain delivery 71 of the varnish post-processing unit 70 are the conveyance unit 105 of the paper P as the entire apparatus. Configure.

<Control system of inkjet printing apparatus>
FIG. 3 is a block diagram showing a schematic configuration of a control system of the ink jet printing apparatus.

  The overall operation of the inkjet printing apparatus 1 is controlled by the computer 100. The computer 100 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and includes a communication unit 101, an operation unit 102, a display unit 103, a storage unit 104, and the like. Is connected.

  The communication unit 101 transmits / receives data to / from an external device such as a host computer. The communication unit 101 includes a known communication interface. The operation unit 102 includes input devices such as a mouse and a keyboard. The display unit 103 includes a display device such as a liquid crystal monitor. The storage unit 104 includes a storage device such as a hard disk device.

  Programs executed by the computer 100 and various data necessary for control are stored in the ROM or the storage unit 104.

  FIG. 4 is a block diagram of functions realized by the computer.

  As illustrated in FIG. 4, the computer 100 executes a predetermined control program, thereby performing a conveyance control unit 110, a paper feed control unit 111, a processing liquid application control unit 112, a processing liquid drying control unit 113, and a printing control unit 114. , The ink drying control unit 115, the varnish application control unit 116, the varnish post-processing control unit 117, the integration control unit 118, and the communication control unit 120.

  The conveyance control unit 110 controls the conveyance unit 105 to control conveyance of the paper P. Specifically, the driving of the conveying means provided in each unit is controlled so that the sheet P fed from the sheet feeding unit 10 is conveyed at a constant speed.

  The paper feed control unit 111 controls the paper feed unit 10 to control the paper feed of the paper P. Specifically, the driving of the elements constituting the paper feed unit 10 is controlled so that the paper P set on the paper feed tray is sequentially fed at a constant speed.

  The treatment liquid application control unit 112 controls the treatment liquid application unit 20 to control application of the treatment liquid to the paper P. Specifically, the drive of each element constituting the processing liquid application unit 20 is controlled so that the processing liquid is applied to the conveyed paper P with a predetermined thickness.

  The processing liquid drying control unit 113 controls the processing liquid drying unit 30 to control drying of the processing liquid applied to the paper P. Specifically, the driving of each element constituting the processing liquid drying unit 30 is controlled so that the processing liquid applied to the paper P is dried.

  The print control unit 114 controls the printing unit 40 to control printing on the paper P. Specifically, the drive of each element constituting the printing unit 40 is controlled so that a predetermined image is printed on the conveyed paper P.

  The ink drying control unit 115 controls the ink drying unit 50 to control ink drying. Specifically, the drive of each element constituting the ink drying unit 50 is controlled so that the ink applied to the paper P by printing is dried. In addition, in the inkjet printing apparatus 1 of this Embodiment, the drying intensity at the time of drying an ink is switched according to the presence or absence of a varnish coat. This will be described in detail later.

  The varnish application control unit 116 controls the varnish application unit 60 to control application of varnish to the paper P. Specifically, depending on whether or not varnish coating is performed, the driving of each element constituting the varnish coating unit 60 is controlled, and in the case of varnish coating, the varnish coating unit is applied so that the varnish is applied with a constant thickness. The driving of each element constituting 60 is controlled.

  The varnish post-processing control unit 117 controls the varnish post-processing unit 70 to control the post-processing of the varnish applied to the paper P. Specifically, the driving of each element constituting the varnish post-processing unit 70 is controlled so that processing according to the type of varnish used when varnish is applied is performed. The varnish post-processing control unit 117 includes a varnish heating control unit 117A and a UV irradiation control unit 117B. The varnish heating control unit 117 </ b> A controls the varnish heating unit 70 </ b> A to control heating of the varnish applied to the paper P. The UV irradiation control unit 117B controls the UV irradiation unit 70B to control the UV irradiation with respect to the varnish applied to the paper P.

  The accumulation control unit 118 controls the accumulation unit 80 to control the accumulation of the paper P. Specifically, the driving of each element constituting the stacking unit 80 is controlled so that the sequentially discharged sheets P are stacked in a bundle.

  The communication control unit 120 controls communication with an external device.

  Furthermore, as shown in FIG. 4, the computer 100 functions as an image processing unit 130, a dry strength determination unit 131, and a heating strength determination unit 132 by executing a predetermined control program.

  The image processing unit 130 performs image processing on image data of an image acquired as a print target, and converts the image data into data that can be printed by the inkjet printing apparatus 1, that is, dot arrangement data of each color. At the time of printing, the inkjet head is driven based on the dot arrangement data.

  The drying strength determination unit 131 determines the drying strength when the ink drying unit 50 dries the ink. This dry strength is determined according to whether or not varnish coating is performed, and is determined according to the type of varnish used. At this time, assuming that the dry strength when not varnished is the first dry strength, the dry strength when varnished with an aqueous varnish is the second dry strength, and the dry strength when varnished with UV varnish is the third dry strength, The second dry strength is a dry strength stronger than the first dry strength, and the third dry strength is a dry strength weaker than the first dry strength. That is, when varnishing with an aqueous varnish, the drying strength is set stronger than when not varnishing, and when varnishing with UV varnish, the drying strength is set weaker than without varnishing. Details are determined based on experiments and the like.

  In the case of an aqueous varnish, if the dry strength is not sufficient, the solvent in the ink is mixed into the aqueous varnish, causing an event that the surface of the varnish layer becomes sticky. This stickiness causes blocking. Therefore, when the varnish is coated with an aqueous varnish, the drying strength is set stronger than when the varnish is not coated, and the solvent in the ink is prevented from being mixed into the aqueous varnish, thereby preventing the occurrence of blocking. However, even if the drying strength is set too high, power is consumed wastefully, so the drying strength is set within an appropriate range.

  On the other hand, in the case of UV varnish, if the drying strength is increased too much, the wax component in the ink is unevenly distributed on the ink surface, resulting in a phenomenon that the adhesion between the ink layer and the varnish layer is lowered. Therefore, in the case of UV varnish, the drying strength is set to be weaker than when varnish is not applied, thereby preventing the wax component from being unevenly distributed on the ink surface and ensuring the adhesion between the ink layer and the varnish layer. However, if the drying strength is lowered too much, the solvent in the ink will be mixed into the UV varnish, and the gloss of the varnish will decrease and blocking will occur during storage. Set.

  The dry strength to be set is managed by a table and stored in the storage unit 104 as a dry strength setting table. The dry strength determining unit 131 refers to this table to determine the dry strength.

  The heating intensity determining unit 132 determines the heating intensity when heating the varnish by the varnish heating unit 70A. This heating intensity is determined based on information on the varnish used. That is, even when UV varnish is used, the varnish is heated as necessary. For example, when an ink containing a wax component is used, when the ink is heated to the melting point or higher of the wax component when the ink is dried, the varnish is heated before UV irradiation even when UV varnish is used. At this time, heating is performed so that the temperature of the image surface is equal to or higher than the melting point of the wax component contained in the ink. Thereby, the diffusion of the wax component unevenly distributed on the image surface to the varnish layer can be accelerated, and the adhesion of the varnish can be improved.

  The heating intensity to be set is managed by a table and stored in the storage unit 104 as a heating intensity setting table. The heating intensity determining unit 132 refers to this table to determine the heating intensity.

<Printing process (inkjet printing method)>
FIG. 5 is a flowchart showing a processing procedure until printing is started by the inkjet printing apparatus.

  The inkjet printing apparatus 1 starts processing in response to an input to the print job (step S1). A print job is input from an external device via the communication unit 101.

  The computer 100 performs image processing on the image data included in the input print job, and generates dot arrangement data (step S2).

  Next, the computer 100 determines the presence or absence of a varnish based on the information included in the input print job (step S3). Based on the determination result, the drying strength for drying the ink is determined (step S4). In the inkjet printing apparatus 1 of the present embodiment, since different types of varnish can be used, when varnish coating is performed, the drying strength is further determined according to the type of varnish used. At this time, as described above, the dry strength when not varnished is the first dry strength, the dry strength when varnished with an aqueous varnish is the second dry strength, and the dry strength when varnished with UV varnish is the third. Assuming the dry strength, the second dry strength is a dry strength stronger than the first dry strength, and the third dry strength is a dry strength weaker than the first dry strength.

  In addition, when the kind of varnish to be used is limited to one kind, the drying strength is determined based only on the presence or absence of the varnish coat. For example, when only an aqueous varnish is used, the dry strength when varnishing is made stronger than the dry strength when not varnishing. When only UV varnish is used, the drying strength when varnishing is made weaker than the drying strength when varnishing is not performed.

  The computer 100 refers to the dry strength setting table stored in the storage unit 104 and determines the dry strength based on the presence / absence of a varnish coat and information on the varnish to be used.

  Next, the computer 100 determines the heating intensity for post-processing the applied varnish (step S5). The heating intensity is determined according to the type of varnish. The computer 100 refers to the heating intensity setting table stored in the storage unit 104 and determines the heating intensity based on the presence / absence of a varnish coat and information on the varnish to be used.

  In the case where the varnish is not applied, the varnish post-processing unit 70 is turned off.

  After completion of the above processing, printing processing is started (step S6).

  FIG. 6 is a flowchart showing a printing processing procedure when varnishing is not performed.

  When printing is started, paper feed is started from the paper feed unit 10 (step S11). The processing liquid is first applied to the printing surface of the paper P fed from the paper supply unit 10 in the processing liquid application unit 20 (step S12). Next, the printing surface of the paper P coated with the treatment liquid is heated by the treatment liquid drying unit 30, and the treatment liquid is heated and dried (step S13). The paper P from which the treatment liquid has been dried is then ejected with ink on the printing surface by the printing unit 40 to print an image (step S14). That is, a printing process is performed. The printed paper P is then heated by the ink drying unit 50 to heat and dry the ink (step S15). That is, an ink drying process is performed. At this time, the ink drying control unit 115 operates the ink drying unit 50 with the dry strength determined by the dry strength determination unit 131 to heat the image surface of the paper P and dry the ink. The paper P on which the ink has been dried passes through the varnish application unit 60 and the varnish post-processing unit 70 and is discharged (step S16) and is collected by the stacking unit 80 (step S17).

  FIG. 7 is a flowchart showing a printing processing procedure in the case of varnish coating.

  When printing is started, paper supply is started from the paper supply unit 10 (step S21). The processing liquid is first applied to the printing surface of the paper P fed from the paper supply unit 10 in the processing liquid application unit 20 (step S22). Next, the printing surface of the paper P coated with the treatment liquid is heated by the treatment liquid drying unit 30 and the treatment liquid is heated and dried (step S23). The paper P from which the treatment liquid has been dried is then ejected with ink on the printing surface by the printing unit 40 to print an image (step S24). That is, a printing process is performed. Next, the surface of the printed paper P is heated by the ink drying unit 50, and the ink is heated and dried (step S25). That is, an ink drying process is performed. At this time, the ink drying control unit 115 operates the ink drying unit 50 with the dry strength determined by the dry strength determination unit 131 to heat the image surface of the paper P and dry the ink.

  This dry strength is the first dry strength when not varnished, the second dry strength when varnished with aqueous varnish, and the third dry strength when varnished with UV varnish. Assuming that the strength is high, the second dry strength is a dry strength stronger than the first dry strength, and the third dry strength is a dry strength weaker than the first dry strength. That is, when varnishing with an aqueous varnish, the drying treatment is performed with a stronger drying strength than when not varnishing, and when varnishing with UV varnish, the drying treatment is performed with a weaker drying strength than when not varnishing.

  The paper P on which the ink has been dried is then coated with a varnish on the image surface by the varnish coating unit 60 (step S26). That is, a varnish application process is performed. The paper P coated with varnish is then subjected to post-processing of the varnish applied to the image surface in the varnish post-processing section 70 (step S27). That is, a varnish post-treatment process is performed. The content of post-processing is switched according to the varnish used. When an aqueous varnish is used, only a heat drying process is performed. When UV varnish is used, a UV irradiation process is performed after a heat treatment is performed as necessary.

  The heat drying process is performed by operating the varnish heating unit 70 </ b> A with the heating intensity determined by the heating intensity determining unit 132. Thereby, when passing through varnish heating part 70A, the image surface where varnish was applied is heated, and the varnish applied to the image surface is cheered.

  The UV irradiation process is performed by operating the UV irradiation unit 70B. As a result, when passing through the UV irradiation unit 70B, the image surface coated with the varnish is irradiated with UV, and the varnish coated on the image surface is UV cured.

  When the varnish heat treatment is performed before the UV irradiation, the varnish heating unit 70A and the UV irradiation unit 70B are operated. The varnish heating control unit 117 </ b> A operates the varnish heating unit 70 </ b> A with the heating intensity determined by the heating intensity determination unit 132 to heat the varnish before UV irradiation.

  The varnish post-processed paper P is discharged at the paper discharge position (step S28) and is collected by the stacking unit 80 (step S29).

  The varnish to be used is switched by changing the type of varnish set on the varnish coater 90.

<< Determination Method of Drying Strength >>
As described above, in the ink jet printing apparatus 1 of the present embodiment, the drying strength for drying the ink is determined according to the presence or absence of the varnish coat. This dry strength is preferably determined according to the following criteria.

<When not varnishing>
When the varnish is not applied, if the dry strength is weak, blocking is likely to occur, and the number of sheets that can be stacked in the stacking unit 80 is limited. Therefore, when not varnishing, it is necessary to set the drying strength to a certain level or more. In consideration of post-processing and backside printing, it is necessary to set the drying strength to a certain level or more. In the case of no varnish coat, there is no problem in quality even if the drying strength is increased, but considering the energy consumption, it is preferable to set the necessary minimum drying strength. Therefore, when there is no varnish coat, it is preferable to set the minimum dry strength, that is, the dry strength that minimizes the energy consumption within a range in which the robust performance of stacker blocking, which is blocking at the time of accumulation, can be secured. Thereby, energy-saving operation becomes possible, ensuring the robust performance of stacker blocking.

<When varnishing with aqueous varnish>
When varnishing with an aqueous varnish, blocking at the time of accumulation also becomes a problem, but the mechanism of the occurrence of the problem is different from that without varnishing. In the case of varnish coating with an aqueous varnish, if the drying strength is not sufficient, the solvent in the ink is mixed into the aqueous varnish (so-called contamination), and the surface of the varnish layer is sticky. In the case of varnish coating, the adhesive surface when the sheets P are stacked is the surface of the varnish layer. The surface of the varnish layer in which the solvent is mixed has a higher adhesive force than the surface without the varnish coat, that is, the surface of the ink layer. Therefore, in the case of varnishing with aqueous bismuth, it is necessary to make the drying strength stronger and volatilize more actively than when varnishing is not performed.

  In particular, in-line coating in which varnish is applied immediately after ink drying cannot reduce the amount of solvent due to penetration, and therefore it is necessary to increase the ink drying strength.

  In addition, since the characteristics of the varnish differ depending on the brand of aqueous bismuth, it is more preferable to adjust the drying strength depending on the brand of varnish. Specifically, the degree of stickiness on the surface of the varnish varies depending on the temperature characteristics of the resin in the varnish (Tg (glass transition point), etc.) and the amount of contamination of the ink solvent due to the difference in compatibility between the aqueous varnish liquid and the ink solvent. There is a case.

<When varnishing with UV varnish>
When varnishing with UV varnish, securing the adhesion between the ink layer and the varnish layer is a problem. In particular, when ink containing a wax component is used, if the ink is dried at a temperature equal to or higher than the melting point of the wax when the ink is dried, the wax component is unevenly distributed on the surface of the ink layer, and the adhesion of the varnish when UV varnish is applied to the surface This causes a problem of lowering. Therefore, when varnishing with UV varnish, the drying strength is set weaker and the temperature during ink drying is lower than when varnishing is not performed. Thereby, it is possible to prevent the wax component from being unevenly distributed on the surface of the ink layer, and it is possible to prevent the adhesion of the varnish from being lowered.

  If the dry strength is too weak, there is a concern that the ink solvent is mixed into the varnish layer as in the case of the aqueous bismuth, and the glossiness is lowered or the blocking property during storage is deteriorated. Therefore, it is preferable to set the drying strength in consideration of these circumstances. Specifically, glossiness and blocking performance during storage may vary depending on the varnish curability and the ink solvent contamination difference due to the compatibility difference between the UV varnish liquid and the ink solvent. In addition, a difference in the degree of re-diffusion of the wax may occur due to a difference in compatibility between the UV varnish liquid and the wax.

<Other parameters>
When setting the drying strength, other parameters such as paper thickness, paper type, total amount of ink applied to the paper, front side printing / back side printing type, and the like can also be used.

  The parameter information may be configured to be input by an operator from the operation unit or may be automatically acquired. Generally, these pieces of information are input before printing as information necessary for printing. Further, the amount of ink applied to the paper can be obtained from the image data of the image to be printed.

<Method of determining heating intensity>
<When varnished with aqueous varnish>
When the aqueous varnish is applied, the image surface of the paper P coated with the varnish is heated to dry the varnish. Thereby, the stickiness of the surface of a varnish layer is suppressed and generation | occurrence | production of blocking is suppressed. Therefore, the heating intensity is set so that sufficient drying can be ensured.

  However, if the heating strength is too strong, the paper temperature during stacking becomes too high, and there is a concern that the blocking performance will deteriorate. Therefore, it is preferable to set to an appropriate strength in consideration of blocking properties during accumulation.

  Further, since the degree of drying varies depending on the thickness of the paper, it is more preferable to control the heating intensity in accordance with the thickness of the paper. In particular, when the thickness of the paper is thin, since the dust is dried by the residual heat at the time of drying the ink, it may be preferable that heating is not performed. Therefore, it is more preferable to set the heating intensity in consideration of the temperature of the paper P at the time of varnish application.

<When varnished with UV varnish>
As described above, when UV varnish is used, heat treatment is performed as necessary. When printing using wax-containing ink, if the image surface is heated above the melting point of the wax component when the ink is dried, set the heating intensity so that it reaches at least the melting point of the wax component, and before UV irradiation Heat the image surface.

[Second Embodiment]
If the varnish coater is not built into the printing device, it cannot be varnished inline. In this case, the varnish is performed off-line or online using a varnish apparatus different from the printing apparatus.

  Here, offline varnishing is a form in which printing and varnishing are performed separately, and each process is performed completely independently. In this case, the sheets accumulated by the printing apparatus are set in the varnish apparatus, and varnish processing is performed. Therefore, the offline varnish has a characteristic that the sheets are once collected after printing. In addition, the time interval from printing to varnish tends to be long.

  On the other hand, online varnishing is a form in which printing and varnishing are continuously performed as a series of processes. Online varnishing is performed by connecting a printing device and a varnishing device in series. That is, the paper discharged from the printing apparatus is fed to the varnish apparatus as it is, thereby enabling continuous processing. Online varnishing is common to inline varnishing in that printing and varnishing are performed continuously, but differs in that printing and varnishing are performed by separate devices. And by this difference, it has the characteristic that the time interval to a varnish coat becomes longer than the inline varnish coat. The online varnish is different from the offline varnish in that the paper discharged from the printing apparatus is fed to the varnish apparatus as it is, and the printed sheets are not collected before the varnish.

[Offline varnish coat]
FIG. 8 is a system configuration diagram of an inkjet printing system that performs varnish coating offline.

  As shown in FIG. 8, the inkjet printing system 200 includes an inkjet printing apparatus 300 that prints on a sheet by an inkjet method, and a varnish coat apparatus 400 that varnishes the sheet.

<Inkjet printer>
<Constitution>
FIG. 9 is a schematic configuration diagram of the ink jet printing apparatus shown in FIG.

  As illustrated in FIG. 9, the inkjet printing apparatus 300 includes a paper feeding unit 310 that feeds the paper P, a processing liquid application unit 320 that applies a processing liquid to the printing surface of the paper P, and a process applied to the paper P. A treatment liquid drying unit 330 that dries the liquid, a printing unit 340 that prints an image on the paper P on which the treatment liquid has been dried by an inkjet method, and an ink drying unit 350 that heats the printing surface of the paper P to dry the ink. And a stacking unit 380 that stacks the printed paper P.

  The configurations of the paper feed unit 310, the treatment liquid application unit 320, the treatment liquid drying unit 330, the printing unit 340, the ink drying unit 350, and the stacking unit 380 are the same as those in the inkjet printing apparatus 1 according to the first embodiment described above. The configuration of each part of the sheet feeding unit 10, the processing liquid application unit 20, the processing liquid drying unit 30, the printing unit 40, the ink drying unit 50, and the stacking unit 80 is substantially the same. That is, the inkjet printing apparatus 300 of the present embodiment is different from the inkjet printing apparatus 1 of the first embodiment described above in that it does not include a varnish application unit and a varnish post-processing unit.

  Since varnishing is not performed inline, the ink jet printing apparatus 300 according to the present embodiment discharges paper after the ink drying process. Therefore, the first chain delivery 51 of the ink drying unit 50 is provided extending to the paper discharge position. The paper P conveyed by the first chain delivery 51 is released from the first chain delivery 51 at the paper discharge position and is collected by the stacking unit 80.

<Control system for inkjet printer>
FIG. 10 is a block diagram showing a schematic configuration of a control system of the ink jet printing apparatus shown in FIG.

  The overall operation of the inkjet printing apparatus 1 is controlled by a computer 500. To the computer 500, a communication unit 501, an operation unit 502, a display unit 503, a storage unit 504, and the like are connected.

  FIG. 11 is a block diagram of functions realized by the computer of the inkjet printing apparatus shown in FIG.

  As illustrated in FIG. 11, the computer 500 executes a predetermined control program to thereby execute a conveyance control unit 510, a paper feed control unit 511, a processing liquid application control unit 512, a processing liquid drying control unit 513, and a printing control unit 514. , Function as an ink drying control unit 515, an accumulation control unit 518, and a communication control unit 520. The function of each unit is as follows: the transport control unit 110, the paper feed control unit 111, the processing liquid application control unit 112, the processing liquid drying control unit 113, the printing control unit 114, and the ink of the inkjet printing apparatus 1 of the first embodiment described above. The functions of the drying control unit 115, the integration control unit 118, and the communication control unit 120 are substantially the same. Therefore, the description is omitted.

  Further, as shown in FIG. 11, the computer 500 functions as an image processing unit 530 and a dry strength determination unit 531 by executing a predetermined control program. The function of each unit is the same as the function of the image processing unit 130 and the dry strength determination unit 131 of the inkjet printing apparatus 1 according to the first embodiment described above. Therefore, the description is omitted.

<Printing process by inkjet printer>
When printing is started, paper feed is started from the paper feed unit 310. The processing liquid is first applied to the printing surface of the paper P supplied from the paper supply unit 310 by the processing liquid application unit 320. Next, the processing liquid drying unit 330 heats the printing surface of the paper P coated with the processing liquid, and the processing liquid is heated and dried. The paper P from which the treatment liquid has been dried is then ejected with ink on the printing surface by the printing unit 340 to print an image. Next, the printed paper P is heated by the ink drying unit 350 so that the ink is heated and dried. At this time, the ink drying control unit 515 operates the ink drying unit 350 with the dry strength determined by the dry strength determination unit 531 to heat the image surface of the paper P and dry the ink. This will be described in detail later. The paper P on which the ink has been dried is discharged at a predetermined discharge position and is stacked by the stacking unit 380.

  When varnishing after printing, the paper P accumulated in the accumulating unit 380 is transported to the varnishing device 400 and set in the paper feeding unit 410 of the varnishing device 400.

《Niss coat device》
<Configuration of varnish coat device>
FIG. 12 is a schematic configuration diagram of the varnish coat apparatus shown in FIG.

  The varnish coating apparatus 400 includes a paper feed unit 410, a varnish application unit 460, a varnish post-processing unit 470, and a stacking unit 480.

[Paper Feeder]
The paper feeding unit 410 feeds sheets that are sheets one by one. As shown in FIG. 12, the paper feed unit 410 mainly includes a paper feed device 411, a feeder board 412, and a paper feed drum 413. The configuration of the paper feed unit 410 is substantially the same as the configuration of the paper feed unit 10 provided in the inkjet printing apparatus 1 of the first embodiment described above. Therefore, the description is omitted.

(Varnish application part)
The varnish application unit 460 applies varnish to the image surface of the paper P. As shown in FIG. 12, the varnish application unit 460 includes a varnish application drum 461 that conveys the paper P along a certain conveyance path, and a varnish coater that applies varnish to the image surface of the paper P conveyed by the varnish application drum 461. 490. The configuration of the varnish application unit 460 is substantially the same as the configuration of the varnish application unit 60 provided in the inkjet printing apparatus 1 of the first embodiment described above. Therefore, the description is omitted.

[Vnish finishing section]
The varnish post-processing unit 470 performs post-processing of the varnish applied to the image surface of the paper P by the varnish application unit 460. As shown in FIG. 12, the varnish post-processing unit 470 includes a chain delivery 471 that transports the paper P along a certain transport path, a paper guide 472 that guides the paper P transported by the chain delivery 471, and a chain delivery. Irradiating UV to the image surface of the paper P conveyed by the chain delivery 471 and the varnish heating unit 470A for heating the image surface of the paper P conveyed by the 471 and drying the varnish applied to the image surface; And a UV irradiation unit 470B that UV cures the varnish applied to the image surface. The configuration of the varnish post-processing unit 470 is substantially the same as the configuration of the varnish post-processing unit 70 provided in the inkjet printing apparatus 1 of the first embodiment described above. Therefore, the description is omitted.

[Accumulator]
The stacking unit 480 stacks the discharged paper P. The stacking unit 480 includes a stacking device 481. The configuration of the stacking unit 480 is substantially the same as the configuration of the stacking unit 80 provided in the inkjet printing apparatus 1 of the first embodiment described above. Therefore, the description is omitted.

<Control system of varnish coat device>
FIG. 13 is a block diagram showing a schematic configuration of a control system of the varnish coat apparatus shown in FIG.

  The overall operation of the varnish coating apparatus inkjet printing apparatus 1 is controlled by a computer 600. To the computer 600, a communication unit 601, an operation unit 602, a display unit 603, a storage unit 604, and the like are connected.

  FIG. 14 is a block diagram of functions realized by the computer of the varnish coat apparatus shown in FIG.

  As illustrated in FIG. 14, the computer 600 executes a predetermined control program, thereby performing a conveyance control unit 610, a paper feed control unit 611, a varnish application control unit 616, a varnish post-processing control unit 617, an accumulation control unit 618, It functions as the communication control unit 620. The varnish post-processing control unit 617 includes a varnish heating control unit 617A and a UV irradiation control unit 617B. The functions of each unit are the conveyance control unit 110, the paper feed control unit 111, the varnish application control unit 116, the varnish post-processing control unit 117, the integration control unit 118, and the communication control of the inkjet printing apparatus 1 according to the first embodiment described above. This is substantially the same as the unit 120, the varnish heating control unit 117A, and the UV irradiation control unit 117B. Therefore, the description is omitted.

  Further, as shown in FIG. 14, the computer 600 functions as a heating intensity determination unit 632 by executing a predetermined control program. The function of the heating intensity determination unit 632 is the same as the function of the heating intensity determination unit 132 of the inkjet printing apparatus 1 according to the first embodiment described above. Therefore, the description is omitted.

<Viscose treatment with varnish coat device>
When the apparatus is operated, paper feeding is started from the paper feeding unit 410. Varnish is applied to the image surface of the paper P fed from the paper supply unit 410 by the varnish application unit 460. The paper P coated with varnish is then subjected to post-treatment of the varnish applied to the image surface in the varnish post-processing section 470. The content of post-processing is switched according to the varnish used. When an aqueous varnish is used, only a heat drying process is performed. When UV varnish is used, a UV irradiation process is performed after a heat treatment is performed as necessary. The post-processed paper P is discharged at the paper discharge position and is collected by the stacking unit 480.

  The varnish to be used is switched by changing the type of varnish set on the varnish coater 490.

<< Determination Method of Drying Strength in Inkjet Printing Apparatus >>
Also in the inkjet printing apparatus 300 of the present embodiment, the drying strength for drying the ink is determined according to the presence or absence of the varnish coat.

  In this case, the dry strength when not varnished is the first dry strength, the dry strength when varnished with an aqueous varnish is the second dry strength, and the dry strength when varnished with UV varnish is the third dry strength, The second dry strength is a dry strength stronger than the first dry strength, and the third dry strength is a dry strength weaker than the first dry strength. That is, when varnishing with an aqueous varnish, the drying strength is set stronger than when not varnishing, and when varnishing with UV varnish, the drying strength is set weaker than without varnishing. Details are determined based on experiments and the like.

  The dry strength to be set is managed by a table and stored in the storage unit 504 as a dry strength setting table. The dry strength determining unit 531 refers to this table to determine the dry strength.

  Even if the varnishes are of the same type, the influence on blocking or the like is different if the brands are different, so it is preferable to determine the drying strength for each varnish having a different brand.

  Information on the presence or absence of varnish is input by the operator from the operation unit 502, for example. At this time, when varnishing, information on the type of varnish to be used is also input. The dry strength determination unit 531 determines the dry strength based on the input information.

  The method for acquiring the information on the presence / absence of varnish and the information on the varnish to be used is not particularly limited. In addition, for example, it may be configured to acquire from an external device via the communication unit 501.

<< Method for determining heating strength in varnish coater >>
<When varnished with aqueous varnish>
When an aqueous varnish is applied, the image surface is heated to dry the varnish. Therefore, the heating intensity is set so that sufficient drying can be ensured.

  However, if the heating strength is too strong, the paper temperature during stacking becomes too high, and there is a concern that the blocking performance will deteriorate. Therefore, it is preferable to set to an appropriate strength in consideration of blocking properties during accumulation.

  Further, since the degree of drying varies depending on the thickness of the paper, it is more preferable to control the heating intensity in accordance with the thickness of the paper. In this case, information on the thickness of the paper is acquired and the heating intensity is set.

<When varnished with UV varnish>
When using UV varnish, heat treatment is performed as necessary. When printing using wax-containing ink, if the image surface is heated above the melting point of the wax component when the ink is dried, set the heating intensity so that it reaches at least the melting point of the wax component, and before UV irradiation Heat the image surface. In this case, the temperature information of the image surface at the time of ink drying is acquired, and the heating intensity is determined. Therefore, in this case, as the ink jet printing system, a temperature measuring unit that measures the temperature of the image surface during ink drying is incorporated in the ink jet printing apparatus.

[Third Embodiment]
[Online varnish coat]
"System configuration"
FIG. 15 is a system configuration diagram of an inkjet printing system that performs varnish coating online.

  As shown in FIG. 15, the inkjet printing system 700 includes an inkjet printing apparatus 300 that prints on a sheet of paper by an inkjet method, a varnish coating apparatus 400 that varnishes a sheet of paper, and a sheet that is discharged from the inkjet printing apparatus 300. And a transfer device 710 for transferring P to the varnish coat device 400.

  The configurations of the inkjet printing apparatus 300 and the varnish coating apparatus 400 are substantially the same as the configurations of the inkjet printing apparatus 300 and the varnish coating apparatus 400 of the inkjet printing system 200 of the second embodiment described above. The inkjet printing apparatus 300 and the varnish coating apparatus 400 of the inkjet printing system 200 of the second embodiment described above are connected in series by the transfer device 710 so that a series of processes from printing to varnish coating can be performed continuously. doing.

  The transfer device 710 includes a conveyor 712, and the paper P discharged from the discharge position of the inkjet printing apparatus 300 is transferred to the varnish coat device 400 by the conveyor 712. The conveyor 712 receives the paper P discharged from the discharge position of the ink jet printing apparatus 300, conveys it to a predetermined conveyance path, and delivers it to the paper supply unit 410 of the varnish coating apparatus 400. The paper feed unit 410 of the varnish coating apparatus 400 receives the paper P from the conveyor 712 and sequentially feeds the paper P to the varnish application unit 460.

  The collection of the paper P is performed by the stacking unit 480 of the varnish coating device 400. The sheets P are stacked and collected in a bundle by the stacking unit 480 of the varnish coat apparatus 400.

  At the time of printing, the inkjet printing apparatus 300 and the varnish coating apparatus 400 operate in conjunction with each other. When the varnish coating is not performed, the varnish application function and the varnish post-processing function of the varnish coat apparatus 400 are stopped. In this case, the paper P passes through the varnish application unit 460 and the varnish post-processing unit 470 of the varnish coating apparatus 400 and is stacked by the stacking unit 480.

《Print processing》
The procedure of the printing process is substantially the same as that of the inkjet printing apparatus 1 of the first embodiment described above. That is, the printing process is performed in response to the input to the print job.

  First, as pre-printing processing, image data included in an input print job is subjected to image processing to generate dot arrangement data. Next, based on the information included in the input print job, the presence or absence of varnish is determined. Then, based on the determination result, the drying strength for drying the ink is determined. In the case of varnish coating, the heating strength for post-processing the varnish is determined.

  When printing is started, paper feeding is started from the paper feeding unit 310 of the inkjet printing apparatus 300. The processing liquid is first applied to the printing surface of the paper P supplied from the paper supply unit 310 by the processing liquid application unit 320. Next, the processing liquid drying unit 330 heats the printing surface of the paper P coated with the processing liquid, and the processing liquid is heated and dried. The paper P from which the treatment liquid has been dried is then ejected with ink on the printing surface by the printing unit 340 to print an image. Next, the printed paper P is heated by the ink drying unit 350 so that the ink is heated and dried. At this time, the ink drying control unit 515 operates the ink drying unit 350 with the dry strength determined by the dry strength determination unit 531 to heat the image surface of the paper P and dry the ink. The paper P on which the ink has been dried is conveyed to a paper discharge position and discharged.

  The paper P discharged from the inkjet printing apparatus 300 is transferred to the varnish coat apparatus 400 by the transfer apparatus 710.

  The paper P transferred to the varnish coating device 400 passes through the varnish application unit 460 and the varnish post-processing unit of the varnish coating device 400 and is collected by the stacking unit 480.

<When applying varnish>
When printing is started, paper feeding is started from the paper feeding unit 310 of the inkjet printing apparatus 300. The processing liquid is first applied to the printing surface of the paper P supplied from the paper supply unit 310 by the processing liquid application unit 320. Next, the processing liquid drying unit 330 heats the printing surface of the paper P coated with the processing liquid, and the processing liquid is heated and dried. The paper P from which the treatment liquid has been dried is then ejected with ink on the printing surface by the printing unit 340 to print an image. Next, the printed paper P is heated by the ink drying unit 350 so that the ink is heated and dried. At this time, the ink drying control unit 515 operates the ink drying unit 350 with the dry strength determined by the dry strength determination unit 531 to heat the image surface of the paper P and dry the ink. The paper P on which the ink has been dried is conveyed to a paper discharge position and discharged.

  The paper P discharged from the inkjet printing apparatus 300 is transferred to the varnish coat apparatus 400 by the transfer apparatus 710.

  The paper P transferred to the varnish coating device 400 is fed to the varnish coating unit 460 via the paper feeding unit 410 of the varnish coating device 400, and the varnish is coated on the image surface by the varnish coating unit 460. The paper P coated with varnish is then subjected to post-processing of the varnish applied to the image surface in the varnish post-processing section 70. The content of post-processing is switched according to the varnish used. When an aqueous varnish is used, only a heat drying process is performed. When UV varnish is used, a UV irradiation process is performed after a heat treatment is performed as necessary. The varnish post-processed paper P is discharged at the paper discharge position and is collected by the stacking unit 480 of the varnish coating apparatus 400.

<< Determination Method of Drying Strength >>
Also in the ink jet printing system 700 of the present embodiment, the drying strength when the ink is dried is determined according to the presence or absence of the varnish coat. The method for determining the dry strength is substantially the same as the method for determining the dry strength in the inkjet printing apparatus 1 of the first embodiment described above. Therefore, the description is omitted.

<Method of determining heating intensity>
The method for determining the heating intensity at the time of varnish post-treatment is also substantially the same as the method for determining the heating intensity in the inkjet printing apparatus 1 of the first embodiment described above. Therefore, the description is omitted.

[Other embodiments]
<Ink drying section>
In the above embodiment, the first heating device 53 is configured by a plurality of heaters arranged along the sheet conveyance path, and the sheet is heated by the heat from the heater to dry the ink. The mechanism for drying the ink is not limited to this. Any structure that can adjust at least the drying strength may be used. Therefore, for example, a configuration may be adopted in which hot air is blown and dried. In this case, the drying strength can be adjusted by adjusting the temperature and / or air volume of the hot air. Moreover, a heating apparatus can also be comprised combining a heater and a hot air blowing means.

  The heater can also be configured in a planar shape. In this case, for example, the drying intensity is adjusted by the lighting duty ratio.

<Varnish application part>
In the above embodiment, the varnish is applied to the paper by a so-called roll coater. However, the configuration of the varnish application portion is not limited to this. In addition, for example, a varnish can be applied to the paper using a varnish coater such as a chamber coater.

  Moreover, it can also be set as the structure which can switch automatically the varnish to be used. In this case, for example, a tank for supplying aqueous varnish and a tank for supplying UC varnish are provided, and the supply destination of the varnish liquid can be arbitrarily switched.

<Variet aftertreatment>
As described above, the content of the varnish post-treatment varies depending on the type of varnish used. That is, when the varnish to be used is an aqueous varnish, the post-treatment is a heat drying treatment. On the other hand, when the varnish to be used is UV varnish, the post-treatment is mainly UV curing treatment.

  Therefore, in the case of varnish coating in-line, when the varnish used is only an aqueous varnish, the varnish post-treatment part can be constituted only by a varnish heating part. In this case, the varnish post-processing unit is controlled based only on information on whether or not to varnish. That is, only when varnishing, the varnish post-processing section is operated to perform post-processing of the varnished paper.

  Similarly, when the varnish is applied off-line or on-line, and the varnish to be used is only an aqueous varnish, the varnish post-treatment section can be composed of only the varnish heating section.

  Further, in the case where varnish coating is performed in-line, and the varnish used is only UV varnish, the varnish post-processing section can be composed of only the UV irradiation section, or can be composed of the varnish heating section and the UV irradiation section. Also in this case, the varnish post-processing unit is controlled based only on the information on whether or not to varnish. That is, only when varnishing, the varnish post-processing section is operated to perform post-processing of the varnished paper.

  Similarly, when varnishing is performed offline or online and the varnish used is only UV varnish, the varnish post-treatment part is composed of only the varnish heating part or composed of the varnish heating part and the UV irradiation part. Can do.

  In addition, about a varnish heating part, what is necessary is just a structure which can adjust a heating intensity at least. Therefore, for example, a configuration may be adopted in which hot air is blown and dried. In this case, the heating intensity can be adjusted by adjusting the temperature and / or air volume of the hot air. Moreover, a varnish heating part can also be comprised combining a heater and a hot air blowing means.

  Further, when the varnish is applied off-line, the heating strength can be adjusted by adjusting the sheet conveyance speed. That is, when varnishing offline, the paper transport speed in the varnishing device can be set independently of the paper transport speed in the inkjet printing apparatus, so the heating strength is adjusted by adjusting the paper transport speed. be able to. In this case, the heating intensity is increased by decreasing the conveying speed, and the heating intensity is decreased by increasing the conveying speed.

<About treatment liquid>
About a process liquid, it selects suitably according to the ink to be used. The treatment liquid only needs to have a function of aggregating the pigment and / or self-dispersing polymer particles in the ink to be used. In the implementation of the present invention, it is not always necessary to apply the treatment liquid. A configuration in which the treatment liquid application step is omitted is also possible.

<Paper>
In carrying out the present invention, the material of the paper is not particularly limited. The present invention can also be applied to printing on resin or cloth paper.

<Recording method using inkjet head>
In the above-described embodiment, the line method using the line head is exemplified, but as the inkjet head, a shuttle method using a serial head can also be adopted.

  Experiments were conducted to confirm the effect on the image quality by changing the drying strength and drying the ink. The experiment was conducted for each of the cases where the varnish was not applied, the aqueous varnish was applied, and the UV varnish was applied.

《When not varnishing》
When the ink is not varnished, the effect of the drying strength upon drying of the ink on the image quality is mainly stacker blocking which is blocking at the time of accumulation. Therefore, an experiment for evaluating the stacker blocking property was conducted when the ink was not varnished.

<Evaluation method for stacker blocking properties>
Using magenta ink and cyan ink, 1000 single-sided prints of a blue stripe image having a width of 50 [mm] are performed. The ink amount is 5.0 [pL] (5000 [μm ³ ]). The state of occurrence of blocking of the paper accumulated in the accumulating portion after 6 hours is confirmed and evaluated in four stages of A, B, C, and D. The evaluation criteria for A, B, C, and D are as follows.

A: No blocking occurred B: Slight blocking occurred, but acceptable level C: Blocking occurred below the 500th sheet from the top of the stacked paper bundle (there is a white part)
D: Blocking occurs below the first sheet from the top of the stacked sheet bundle. Evaluation A is “VERY GOOD”, Evaluation B is “GOOD”, Evaluation C is “BAD”, and Evaluation D is “VERY BAD”. The

  As the ink, an ink having a wax content of 2 [% by mass] was used.

<When varnishing with aqueous varnish>
In the case of varnishing with an aqueous varnish, the effect of the drying strength at the time of ink drying on the image quality is mainly stacker blocking, which is blocking at the time of accumulation. The experiment was conducted.

<Evaluation method for stacker blocking properties>
Using magenta ink and cyan ink, 1000 single-sided blue stripe images of 50 [mm] width are printed, and the image surface is varnished with an aqueous varnish. The ink amount is 5.0 [pL] (5000 [μm ³ ]). The state of occurrence of blocking of the paper accumulated in the accumulating portion after 6 hours is confirmed, and evaluation is performed in three stages of A, B, and C. The evaluation criteria for A, B, and C are as follows.

A: No blocking occurs B: Blocking occurs below the 500th sheet from the top of the stacked paper bundle (there is a part that is white)
C: Blocking occurs below the first sheet from the top of the stacked sheet bundle Evaluation A is determined as “GOOD”, evaluation B is determined as “BAD”, and evaluation C is determined as “VERY BAD”.

<< When varnishing with UV varnish >>
In the case of varnish coating with UV varnish, the influence of the drying strength upon drying of the ink on the image quality is mainly varnish adhesion, varnish glossiness, and storage blocking, which is blocking during storage. In the case of varnish coating, an experiment was conducted to evaluate varnish adhesion, varnish glossiness, and storage blocking properties.

<Evaluation method for adhesion of varnish>
Using all four colors of cyan, magenta, yellow and black, a 4C stripe image having a width of 50 [mm] is printed on one side, and the image surface is varnished with UV varnish. A cellophane tape (made by Nichiban Co., Ltd.) with a width of 18 [mm] is applied to the coated surface with a length of about 40 [mm] and pulled vertically to check the peeled state of the varnish layer from the surface of the ink layer Then, the evaluation is made in three stages of A, B, and C. The evaluation criteria are as follows.

A: No peeling or paper breaks B: Partial peeling C: Peeling on the entire surface Evaluation A is “GOOD”, evaluation B is “BAD”, and evaluation C is “VERY BAD”.

  Note that 4C is the color of an image when printing is performed using all four colors of cyan, magenta, yellow, and black, and is high-density black.

  About adhesion, it becomes so low that a density | concentration is deep. This is because the higher the density, the greater the amount of droplet ejection and the greater the amount of wax contained in the image. Further, the black color tends to increase the film surface temperature when the ink is dried, and the wax tends to be unevenly distributed on the ink surface. That is, the most severe condition of the adhesion performance of UV varnish is the case where the amount of droplet ejection is the largest in the black color, and it is the case of 4C that uses all four colors of ink and expresses high density black. . Therefore, varnish adhesion is evaluated by printing at 4C.

<Evaluation method for glossiness of varnish>
Using all four colors of cyan, magenta, yellow and black, a 4C stripe image having a width of 50 [mm] is printed on one side, and the image surface is varnished with UV varnish. The gloss of the varnished surface is measured at a measurement angle of 60 °, and the gloss is evaluated in three stages of A, B, and C. The evaluation criteria are as follows.

A: 70 or more B: 56 or more and 69 or less C: 55 or less Evaluation A is determined as “GOOD”, evaluation B is determined as “BAD”, and evaluation C is determined as “VERY BAD”.

  For the gloss measurement, a gloss meter “Micro Trigloss” manufactured by Orwell Co., Ltd. was used.

[Evaluation method for storage blocking properties]
Using all four colors of cyan, magenta, yellow and black, a 4C stripe image having a width of 50 [mm] is printed on one side, and the image surface is varnished with UV varnish. The printed paper is cut to a size of 3.5 [cm] × 4.0 [cm]. Using the cut paper as a sample, 10 samples are stacked and sandwiched between acrylic plates. At this time, all the samples are overlapped with the varnish application surface facing up. Place the acrylic plate on a horizontal base, place a weight of 7 [kg] on the acrylic plate, weight it, and leave it for 24 hours in an environment of temperature 50 [° C.] and humidity 80%. Then, it is further left for 24 hours in an environment of a temperature of 23 [° C.] and a humidity of 50%. The sample is peeled off, the occurrence of blocking is confirmed, and evaluation is performed in three stages of A, B, and C. The evaluation criteria are as follows.

A: No blocking occurs B: Blocking occurs below the 500th sheet from the top of the stacked paper bundle (there is a part that is white)
C: Blocking occurs below the first sheet from the top of the stacked sheet bundle Evaluation A is determined as “GOOD”, evaluation B is determined as “BAD”, and evaluation C is determined as “VERY BAD”.

  As the ink, an ink having a wax content of 2 [% by mass] was used.

"Experimental result"
The experiment was conducted for varnishing inline, varnishing online, and varnishing offline.

<In-line varnish coating>
Experiments were performed using the inkjet printing apparatus 1 shown in FIG.

  In addition, the ink drying unit 50 configured the first heating device 53 by arranging 13 IR heaters at regular intervals along the transport path of the paper P.

  At the time of drying, all 13 IR heaters were operated, and the lighting intensity was adjusted by changing the lighting duty ratio. Specifically, the drying strength was adjusted by adjusting the ON / OFF time of driving of the IR heater with a period of 300 ms. In this case, for example, if the lighting duty ratio is 90%, 270 ms on and 30 ms off are periodically repeated.

  The input power is 4 kW at a lighting duty ratio of 100% per IR heater. Since there are 13 IR heaters, the total is 52 KW.

  Further, the varnish heating unit 70 </ b> A of the varnish post-processing unit 70 configured the second heating device 73 by arranging four IR heaters at regular intervals along the transport path of the paper P. During heating, all four IR heaters were operated, and the heating intensity was adjusted by changing the lighting duty ratio. As with the ink drying unit 50, the heating intensity was adjusted by adjusting the ON / OFF time for driving the IR heater at a cycle of 300 ms. The input power is 4 kW at a lighting duty ratio of 100% per IR heater.

  The ink used was an ink having a wax content of 2 [mass%].

  In addition, “HYDLITH2012-R1” (product name) manufactured by DIC Graphics Co., Ltd. was used as the aqueous varnish. Further, the heating intensity when the aqueous varnish was dried by heating was set to a lighting duty ratio of 25%.

  Moreover, “UV coat varnish TG-2” (product name) manufactured by T & K TOKA Co., Ltd. was used as the UV varnish. Moreover, it was set as the structure which heats UV varnish before UV irradiation, and the heating intensity at that time was set to the lighting duty ratio 50%.

  The experiment was performed using two types of paper, the first paper and the second paper. As the first paper, “NEW DV” (product name) USP 310 [GSM] manufactured by Hokuetsu Kishu Paper Co., Ltd. was used. As the second paper, “bon ivory” (product name) manufactured by Oji Paper Co., Ltd. was used.

In addition, US tsubo [GSM] is a unit indicating a paper thickness of 1 [g] per 1 [m ² ].

  FIG. 16 is a table showing experimental results when inline varnishing is performed using the first paper. FIG. 17 is a table showing experimental results when inline varnishing is performed using the second paper. In each case, experimental results are shown in the case of not varnishing, varnishing with aqueous varnish, and varnishing with UV varnish.

  It can be confirmed from the tables of the experimental results in FIGS. 16 and 17 that the image quality can be improved by changing the drying strength depending on the presence or absence of the varnish coat.

  For example, when not varnishing, stacker blocking becomes a problem. As shown in FIGS. 16 and 17, it can be confirmed that this can be improved by increasing the drying strength when the varnish is not applied. Therefore, when not varnishing, it is preferable to increase the drying strength.

  However, if the drying strength is increased, the energy consumption increases. Therefore, it is preferable to set the optimum drying strength in consideration of the energy consumption. Therefore, when varnishing is not performed, it is preferable to set the drying strength to a minimum energy consumption within a range in which the stacker blocking robustness can be secured.

  Stacker blocking is also an issue when varnishing with an aqueous varnish. As shown in FIGS. 16 and 17, it can be confirmed that this can be improved by increasing the drying strength even when varnishing with an aqueous varnish. Therefore, it is preferable to increase the drying strength even when varnishing with an aqueous varnish. In this case, it is preferable to set the optimum drying strength in consideration of energy consumption, as in the case of no varnish coating. That is, it is preferable to set the drying strength to the minimum energy consumption within a range in which the robustness of stacker blocking can be ensured.

  A comparison between the case of not varnishing and the case of varnishing with aqueous varnish confirms that the dry strength when varnishing with aqueous varnish needs to be stronger than the dry strength when not varnishing. Accordingly, when printing is performed by switching between the case where varnish coating is not performed and the case where varnish coating is performed using an aqueous varnish, it is preferable to perform printing while switching the drying strength. In this case, the drying strength when varnishing with an aqueous varnish is set stronger than the drying strength when not varnishing. Thereby, energy consumption can be suppressed, ensuring the robust performance of stacker blocking.

  When varnishing with UV varnish, adhesion, gloss, and storage blocking are problems. As shown in FIGS. 16 and 17, the glossiness and storage blocking can be improved by increasing the dry strength, but the adhesion can be confirmed to decrease conversely when the dry strength is increased. Therefore, it can be confirmed that it is necessary to set the drying strength from the viewpoints of adhesion and gloss, and both adhesion and storage blocking.

  As described above, when varnish is not applied, stacker blocking can be improved by increasing the drying strength. Therefore, when printing is performed by switching between the case where varnish is not applied and the case where varnish is applied with UV varnish, it is preferable to perform printing while switching the drying strength. In this case, the drying strength when varnishing with UV varnish is set to be weaker than the drying strength when varnishing is not performed. Thereby, when varnishing with UV varnish, adhesiveness, glossiness, and storage blocking performance can be secured, and when varnishing is not performed, robust performance of stacker blocking can be secured.

<When varnishing online>
Experiments were performed using the inkjet printing system 700 shown in FIG.

  The ink drying unit of the ink jet printing apparatus 300 is configured by arranging 13 IR heaters at regular intervals along the transport path of the paper P.

  At the time of drying, all 13 IR heaters were operated, and the lighting intensity was adjusted by changing the lighting duty ratio. Specifically, the drying strength was adjusted by adjusting the ON / OFF time of driving of the IR heater with a period of 300 ms. The input power is 4 kW at a lighting duty ratio of 100% per IR heater. Since there are 13 IR heaters, the total is 52 KW.

  Further, the varnish heating unit of the varnish coater 400 constituted a heating device by arranging four IR heaters at regular intervals along the transport path of the paper P.

  During heating, all four IR heaters were operated, and the heating intensity was adjusted by changing the lighting duty ratio. As with the ink drying unit 50, the heating intensity was adjusted by adjusting the ON / OFF time for driving the IR heater at a cycle of 300 ms. The input power is 4 kW at a lighting duty ratio of 100% per IR heater.

  The ink, aqueous varnish, and UV varnish used are the same as those used for varnish coating in-line. In addition, the heating intensity of the varnish when the aqueous varnish was used was set to a lighting duty ratio of 25%, and the heating intensity of the varnish when the UV varnish was used was set to a lighting duty ratio of 50%.

  The experiment was performed using two types of paper, the first paper and the second paper, as in the case of inline. As the first paper and the second paper, the same paper as in the case of varnishing inline was used.

  FIG. 18 is a table showing experimental results when online varnishing is performed using the first sheet. FIG. 19 is a table showing experimental results when online varnishing is performed using the second paper. In each case, experimental results are shown in the case of not varnishing, varnishing with aqueous varnish, and varnishing with UV varnish.

  It can be confirmed from the tables of the experimental results in FIGS. 18 and 19 that the image quality can be improved by changing the drying strength depending on the presence or absence of the varnish even when varnishing online.

  For example, when the varnish is not applied, it can be confirmed that stacker blocking can be improved by increasing the drying strength. Therefore, when not varnishing, it is preferable to increase the drying strength.

  It can be confirmed that stacker blocking can be improved by increasing the drying strength even when varnishing with an aqueous varnish. Therefore, when not varnishing, it is preferable to increase the drying strength.

  A comparison between the case of not varnishing and the case of varnishing with aqueous varnish confirms that the dry strength when varnishing with aqueous varnish needs to be stronger than the dry strength when not varnishing. Therefore, when varnishing online, it is preferable to switch the drying strength depending on the presence or absence of the varnish. In this case, the drying strength when varnishing with an aqueous varnish is set stronger than the drying strength when not varnishing. Thereby, energy consumption can be suppressed, ensuring the robust performance of stacker blocking.

  As in the case of varnishing in-line, it can be confirmed that when varnishing with UV varnish, it is necessary to set the drying strength from the viewpoints of both adhesion and gloss, and adhesion and storage blocking.

  As described above, when varnish is not applied, stacker blocking can be improved by increasing the drying strength. Therefore, when printing is performed by switching between the case where varnish is not applied and the case where varnish is applied with UV varnish, it is preferable to perform printing while switching the drying strength. In this case, the drying strength when varnishing with UV varnish is set to be weaker than the drying strength when varnishing is not performed. Thereby, when varnishing with UV varnish, adhesiveness, glossiness, and storage blocking performance can be secured, and when varnishing is not performed, robust performance of stacker blocking can be secured.

<When varnishing offline>
Experiments were performed using the inkjet printing system 200 shown in FIG.

  The ink drying unit of the ink jet printing apparatus 300 is configured by arranging 13 IR heaters at regular intervals along the transport path of the paper P.

  At the time of drying, all 13 IR heaters were operated, and the lighting intensity was adjusted by changing the lighting duty ratio. Specifically, the drying strength was adjusted by adjusting the ON / OFF time of driving of the IR heater with a period of 300 ms. The input power is 4 kW at a lighting duty ratio of 100% per IR heater. Since there are 13 IR heaters, the total is 52 KW.

  Further, the varnish heating unit of the varnish coater 400 constituted a heating device by arranging four IR heaters at regular intervals along the transport path of the paper P.

  During heating, all four IR heaters were operated, and the heating intensity was adjusted by changing the lighting duty ratio. As with the ink drying unit 50, the heating intensity was adjusted by adjusting the ON / OFF time for driving the IR heater at a cycle of 300 ms. The input power is 4 kW at a lighting duty ratio of 100% per IR heater.

  The ink, aqueous varnish, and UV varnish used are the same as those used for varnish coating in-line. In addition, the heating intensity of the varnish when the aqueous varnish was used was set to a lighting duty ratio of 25%, and the heating intensity of the varnish when the UV varnish was used was set to a lighting duty ratio of 50%.

  The experiment was performed using two types of paper, the first paper and the second paper, as in the case of inline. As the first paper and the second paper, the same paper as in the case of varnishing inline was used.

  FIG. 20 is a table showing experimental results when offline varnishing is performed using the first sheet. FIG. 21 is a table showing experimental results when offline varnishing is performed using the second paper. In each case, experimental results are shown in the case of not varnishing, varnishing with aqueous varnish, and varnishing with UV varnish.

  20 and 21, it can be confirmed that the image quality can be improved by changing the drying strength depending on the presence or absence of the varnish even when the varnish is applied offline.

  For example, when the varnish is not applied, it can be confirmed that stacker blocking can be improved by increasing the drying strength. Therefore, when not varnishing, it is preferable to increase the drying strength.

  It can be confirmed that stacker blocking can be improved by increasing the drying strength even when varnishing with an aqueous varnish. Therefore, when not varnishing, it is preferable to increase the drying strength.

  A comparison between the case of not varnishing and the case of varnishing with aqueous varnish confirms that the dry strength when varnishing with aqueous varnish needs to be stronger than the dry strength when not varnishing. Therefore, when varnishing online, it is preferable to switch the drying strength depending on the presence or absence of the varnish. In this case, the drying strength when varnishing with an aqueous varnish is set stronger than the drying strength when not varnishing. Thereby, energy consumption can be suppressed, ensuring the robust performance of stacker blocking.

  As in the case of varnishing in-line, it can be confirmed that when varnishing with UV varnish, it is necessary to set the drying strength from the viewpoints of both adhesion and gloss, and adhesion and storage blocking.

  As described above, when varnish is not applied, stacker blocking can be improved by increasing the drying strength. Therefore, when printing is performed by switching between the case where varnish is not applied and the case where varnish is applied with UV varnish, it is preferable to perform printing while switching the drying strength. In this case, the drying strength when varnishing with UV varnish is set to be weaker than the drying strength when varnishing is not performed. Thereby, when varnishing with UV varnish, adhesiveness, glossiness, and storage blocking performance can be secured, and when varnishing is not performed, robust performance of stacker blocking can be secured.

<Comparison of inline, online, and offline>
Inline and online results were almost the same. This is presumably because the difference in time from the end of ink drying to varnish application is on the order of seconds, and there is not much difference in the permeation and volatilization state of the ink solvent.

  Compared to inline and online, the stacker blocking property of aqueous varnish was improved in offline. This is presumably because it takes time until the varnish is applied after printing, so that the penetration and volatilization of the ink solvent progresses before the varnish is applied, and the amount of the solvent mixed into the varnish layer is reduced.

  In addition, the glossiness and storage blocking property of the UV varnish were improved in the offline compared with the inline and offline. This is presumably because it takes time until the varnish is applied after printing, so that the penetration and volatilization of the ink solvent progresses before the varnish is applied, and the amount of the solvent mixed into the varnish layer is reduced.

  On the other hand, the adhesiveness of UV varnish deteriorated offline compared to inline and online. This is presumably because the surface of the ink changed from a wet state to a dry state with the passage of time until the varnish was applied, and the wettability of the UV varnish decreased.

《Method for improving adhesion of varnish when applying UV varnish offline》
In the case of varnishing off-line, the paper is once collected by an inkjet printing apparatus and then varnished by a varnishing apparatus.

  Therefore, when varnishing off-line, it is necessary to consider stacker blocking in an ink jet printing apparatus.

  In this regard, when varnishing with an aqueous varnish, the problem of stacker blocking can be solved by simply increasing the drying strength.

  On the other hand, in the case of varnishing with UV varnish, if the drying strength is simply increased, there is a problem that the adhesiveness is lowered. Therefore, if there exists a range in which both adhesion and stacker blocking properties can be achieved, the dry strength is set within the range.

  When the compatibility between the adhesion and the stacker blocking property is severe, it is effective to heat the varnish before UV irradiation. That is, the image surface is heated before UV irradiation to remove the wax component unevenly distributed on the surface of the ink layer, thereby improving the adhesion of the varnish. The heating is performed so that the temperature of the image surface is equal to or higher than the melting point of the wax component contained in the ink.

  In addition, the adjustment of the heating intensity can employ a method of adjusting the sheet conveyance speed in addition to the method of changing the lighting duty ratio of the heating device constituting the varnish heating unit.

  22 and 23 are tables showing experimental results when varnish coating is performed while changing the heating strength of the varnish offline. FIG. 22 shows the experimental results when using the first paper, and FIG. 23 shows the experimental results when using the second paper.

  The experiment was performed by changing the lighting duty ratio of the IR heater of the heating device constituting the varnish heating unit, and the sheet conveyance speed in the varnish coating device.

  In the case of varnishing with an aqueous varnish, the experiment was conducted with the drying strength during ink drying set to a lighting duty ratio of 100%.

  In the case of varnishing with UV varnish, the drying strength at the time of ink drying was set to a lighting duty ratio of 50% for the first paper, and the lighting duty ratio was set to 40% for the second paper. Went.

  As shown in FIG. 22 and FIG. 23, stacker blocking deteriorated when the varnish was not heat-dried when varnished with an aqueous varnish regardless of the type of paper. This is presumably because the moisture and solvent of the varnish were insufficiently dried and the surface of the varnish became sticky.

  As shown in FIG. 22 and FIG. 23, it was confirmed that the adhesiveness was improved by heating the varnish before UV irradiation when varnishing with UV varnish, regardless of the type of paper. Therefore, when varnishing the UV varnish off-line, it is effective to heat the varnish before UV irradiation if compatibility between adhesion and stacker blocking properties is severe.

  24 and 25 are tables showing the experimental results when varnish coating is performed on-line by changing the heating intensity of the varnish. FIG. 24 shows the experimental results when using the first paper, and FIG. 25 shows the experimental results when using the second paper.

  In the same manner as in the offline case, the experiment was performed by changing the lighting duty ratio of the IR heater of the heating device constituting the varnish heating unit and the sheet conveyance speed in the varnish coating device. In the case of varnishing with an aqueous varnish, the experiment was conducted by setting the drying strength during ink drying to a lighting duty ratio of 100%. In the case of varnishing with UV varnish, the drying strength at the time of ink drying was set to a lighting duty ratio of 50% for the first paper, and the lighting duty ratio was set to 40% for the second paper. did.

  As shown in FIGS. 24 and 25, regardless of the type of paper, when varnishing with an aqueous varnish, the stacker blocking deteriorated unless the varnish was heat-dried. This is presumably because the moisture and solvent of the varnish were insufficiently dried and the surface of the varnish became sticky.

  In the case of water-based varnish, stacker blocking deteriorated when the strength of the varnish was 100% regardless of the type of paper. This is presumably because the film surface temperature at the time of accumulation became too high, and the surface of the varnish became easy to stick.

  As shown in FIG. 24 and FIG. 25, it was confirmed that the adhesiveness was improved by heating the varnish before UV irradiation when varnishing with UV varnish, regardless of the type of paper.

  On the other hand, in the case of UV varnish, it was confirmed that the glossiness deteriorates if the varnish is heated too much before UV irradiation. This is presumably because the amount of ink solvent mixed into the varnish layer increased due to heating. Such a phenomenon is likely to occur in-line or on-line when the ink surface layer is rich in solvent.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printing apparatus, 10 ... Paper feed part, 11 ... Paper feed apparatus, 12 ... Feeder board, 13 ... Paper feed drum, 20 ... Treatment liquid application part, 21 ... Treatment liquid application drum, 22 ... Treatment liquid application apparatus, DESCRIPTION OF SYMBOLS 30 ... Processing liquid drying part, 31 ... Processing liquid drying drum, 32 ... 1st paper guide, 33 ... Dryer, 40 ... Printing part, 41 ... Printing drum, 42 ... Paper pressing roller, 43C, 43M, 43Y, 43K ... Inkjet Head, 44 ... Scanner, 50 ... Ink drying section, 51 ... First chain delivery, 52 ... Second paper guide, 53 ... First heating device, 60 ... Varnish application section, 61 ... Varnish application drum, 70 ... Varnish post-treatment 70A ... Varnish heating part, 70B ... UV irradiation part, 71 ... Second chain delivery, 72 ... Third paper guide, 74 ... UV irradiation device, 80 ... Accumulation part, 81 ... Collection Equipment: 90 ... Varnish coater, 91 ... Varnish tank, 92 ... Pumping roller, 93 ... Metering blade, 94 ... First intermediate transfer roller, 95 ... Second intermediate transfer roller, 96 ... Varnish application roller, 100 ... Computer, 101 ... Communication unit 102 ... Operation unit 103 ... Display unit 104 ... Storage unit 105 ... Conveyance unit 110 ... Conveyance control unit 111 ... Feed control unit 112 ... Treatment liquid application control unit 113 ... Treatment liquid drying Control unit 114 ... Print control unit 115 ... Ink drying control unit 116 ... Varnish application control unit 117 ... Varnish post-processing control unit 117A ... Varnish heating control unit 117B ... UV irradiation control unit 118 ... Integration control unit , 120 ... communication control unit, 130 ... image processing unit, 131 ... drying intensity determination unit, 132 ... heating intensity determination unit, 200 ... inkjet printing system, 300 ... Inkjet printing device, 310 ... paper feed unit, 320 ... treatment liquid application unit, 330 ... treatment liquid drying unit, 340 ... printing unit, 350 ... ink drying unit, 380 ... stacking unit, 400 ... varnish coating device, 410 ... paper feed 411 ... Feeding device, 412 ... Feeder board, 413 ... Feeding drum, 460 ... Varnish coating unit, 461 ... Varnish coating drum, 470 ... Varnish post-processing unit, 470A ... Varnish heating unit, 470B ... UV irradiation unit, 471 ... Chain delivery, 472 ... Paper guide, 480 ... Accumulating unit, 481 ... Accumulating device, 490 ... Vnish coater, 500 ... Computer, 501 ... Communication unit, 502 ... Operating unit, 503 ... Display unit, 504 ... Storage unit, 510 ... Transport control unit, 511... Paper feed control unit, 512... Processing liquid application control unit, 513... Processing liquid drying control unit, 514. Drying control unit, 518 ... Accumulation control unit, 520 ... Communication control unit, 530 ... Image processing unit, 531 ... Drying strength determination unit, 600 ... Computer, 601 ... Communication unit, 602 ... Operation unit, 603 ... Display unit, 604 ... Storage unit 610 ... Conveyance control unit 611 ... Paper feed control unit 616 ... Varnish application control unit 617 ... Varnish post-processing control unit 617A ... Varnish heating control unit 617B ... UV irradiation control unit 618 ... Integration control Part, 620 ... communication control part, 632 ... heating intensity determination part, 700 ... inkjet printing system, 710 ... transfer device, 712 ... conveyor, P ... paper

Claims (15)

A printing unit that prints an image on a paper by an inkjet method;
An ink drying unit that heats an image surface of the paper printed by the printing unit to dry the ink, and an ink drying unit capable of adjusting a drying intensity indicating a degree of strength to dry;
Obtaining information on whether or not to varnish the image surface, based on the obtained information, a drying strength determination unit that determines the drying strength when drying the ink in the ink drying unit,
An ink drying control unit for controlling the ink drying unit, wherein the ink drying control unit operates the ink drying unit with the drying strength determined by the drying strength determination unit;
Bei to give a,
The drying strength determination unit further acquires information on the varnish to be used, and determines the drying strength when drying the ink in the ink drying unit based on the acquired information.
Inkjet printing device. When the varnish to be used is an aqueous varnish or UV varnish, the dry strength when there is no varnish coat is the first dry strength, the dry strength when varnished with the aqueous varnish is the second dry strength, when the varnish is coated with UV varnish When the dry strength is the third dry strength, the second dry strength is a stronger dry strength than the first dry strength, and the third dry strength is greater than the first dry strength. Also considered to be weak dry strength,
The inkjet printing apparatus according to claim 1 . A printing unit that prints an image on a paper by an inkjet method;
An ink drying unit that heats an image surface of the paper printed by the printing unit to dry the ink, and an ink drying unit capable of adjusting a drying intensity indicating a degree of strength to dry;
Obtaining information on whether or not to varnish the image surface, based on the obtained information, a drying strength determination unit that determines the drying strength when drying the ink in the ink drying unit,
An ink drying control unit for controlling the ink drying unit, wherein the ink drying control unit operates the ink drying unit with the drying strength determined by the drying strength determination unit;
Bei to give a,
When the varnish to be used is a UV varnish, the drying strength determining unit sets the drying strength when varnishing to a lower drying strength than the drying strength without varnishing,
Inkjet printing device. A varnish application unit that applies varnish to the image surface of the paper after the ink has been dried by the ink drying unit;
A varnish post-processing section for post-processing the varnish applied to the image surface by the varnish application section;
Obtaining information on whether or not to varnish the image surface, based on the obtained information, a varnish application control unit that controls the varnish application unit,
Obtaining information on whether to varnish the image surface, based on the obtained information, a varnish post-processing control unit that controls the varnish post-processing unit,
The inkjet printing apparatus according to claim 1, further comprising: The varnish post-processing unit includes a varnish heating unit that heats the varnish applied to the image surface, and a UV irradiation unit that irradiates UV to the varnish applied to the image surface,
The varnish post-processing control unit further acquires varnish information to be used, and controls the varnish post-processing unit based on the acquired information.
The ink jet printing apparatus according to claim 4 . The varnish post-processing control unit operates the varnish heating unit and the UV irradiation unit when varnishing the image surface with UV varnish,
The ink jet printing apparatus according to claim 5 . The varnish heating unit is configured to be capable of adjusting the heating intensity indicating the degree of strength for heating the varnish,
Obtaining information on the varnish to be used, further comprising a heating intensity determination unit for determining the heating intensity when heating the varnish applied to the image surface with the varnish heating unit based on the acquired information,
The varnish post-processing control unit operates the varnish heating unit with the heating intensity determined by the heating intensity determination unit.
The ink jet printing apparatus according to claim 5 or 6 . An inkjet printing apparatus according to any one of claims 1 to 3 ,
A varnish device that receives paper discharged from the inkjet printing apparatus and varnishes the image surface;
An inkjet printing system comprising:
The varnish coat device
A varnish application part for applying varnish to the image surface of the paper;
A varnish post-processing section for post-processing the varnish applied to the image surface by the varnish application section;
Obtaining information on whether to varnish, based on the obtained information, a varnish application control unit that controls the varnish application unit,
Obtaining information on whether to varnish, based on the obtained information, a varnish post-processing control unit that controls the varnish post-processing unit,
Comprising
Inkjet printing system. The varnish post-processing unit includes a varnish heating unit that heats the varnish applied to the image surface, and a UV irradiation unit that irradiates UV to the varnish applied to the image surface,
The varnish post-processing control unit further acquires varnish information to be used, and controls the varnish post-processing unit based on the acquired information.
The ink jet printing system according to claim 8 . The varnish post-processing control unit operates the varnish heating unit and the UV irradiation unit when varnishing the image surface with UV varnish,
The ink jet printing system according to claim 9 . The varnish heating unit is configured to be capable of adjusting the heating intensity indicating the degree of strength for heating the varnish,
Obtaining information on the varnish to be used, further comprising a heating intensity determination unit for determining the heating intensity when heating the varnish applied to the image surface with the varnish heating unit based on the acquired information,
The varnish post-processing control unit operates the varnish heating unit with the heating intensity determined by the heating intensity determination unit.
The ink jet printing system according to claim 9 or 10 . A printing process for printing an image on paper by an inkjet method;
An ink drying process in which the paper on which the image is printed is heated to dry the ink, and the ink is dried based on information on whether or not the image surface is varnished after drying the ink and information on the varnish to be used. An ink drying step in which the drying strength indicating the degree of strength to be determined is determined;
An inkjet printing method comprising: When the varnish to be used is an aqueous varnish or UV varnish, the dry strength when there is no varnish coat is the first dry strength, the dry strength when varnished with the aqueous varnish is the second dry strength, when the varnish is coated with UV varnish When the dry strength is the third dry strength, the second dry strength is a stronger dry strength than the first dry strength, and the third dry strength is greater than the first dry strength. Also considered to be weak dry strength,
The ink jet printing method according to claim 12 . A printing process for printing an image on paper by an inkjet method;
An ink drying process in which the paper on which the image is printed is heated to dry the ink, and the degree of strength to dry is determined based on information on whether or not the image surface is varnished after the ink is dried. An ink drying process in which the drying strength shown is determined;
An inkjet printing method comprising :
When the varnish to be used is UV varnish, the drying strength when varnishing is assumed to be weaker than the drying strength without varnishing,
Inkjet printing method. When the image surface is varnished with UV varnish, the varnish applied to the image surface is heated before irradiating the varnish applied to the image surface with UV,
The inkjet printing method of any one of Claims 12-14 .

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