JP2006035796A - Image protection method and overcoat apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image protection capable of forming a protective layer covering an image surface without causing inconveniences such as a transfer layer transfer failure and a recording medium undulation even for an ink jet recording medium having a resin-coated paper as a support. A method and an overcoat apparatus excellent in operability that are optimal for the implementation of the image protection method.
An overcoat apparatus (1) includes a heat roller pair (9) that heats and presses a superimposed printed matter (P) and a heat transfer film (71), and at least a plurality of overcoat processing modes having different roller surface temperatures of the heat roller pair (9). Based on the information relating to the printed matter P, which is stored in advance, one overcoat processing mode can be selected from these.
[Selection] Figure 2

Description

  The present invention relates to an image protection method for covering an image surface of a printed matter produced by an inkjet recording method with a protective layer, and an overcoat apparatus for carrying out the image protection method.

  The ink jet recording method is a printing method in which an image is formed by ejecting ink droplets from fine nozzles and attaching them to a recording medium. Conventionally, an ink-jet recording medium having an ink-receiving layer formed on a paper support has been used. However, in recent years, there has been an increasing demand for high-quality ink-jet printed materials with a silver salt photographic tone, which can be realized. As an ink jet recording medium, a medium in which an ink receiving layer is formed on resin-coated paper in which both surfaces of paper are coated with a resin such as polyethylene has been used (for example, see Patent Document 1). Ink jet recording media using such a resin-coated paper as a support have greatly improved gloss, texture, water resistance, etc. compared to those using a paper support, providing photo-like image quality. It is possible.

As described above, the ink jet recording method is comparable to silver salt photography in terms of image quality, but the weather resistance of images is not as good as silver salt photography, and there is room for improvement in terms of long-term storage of printed matter. large. As a method for improving the storability of a printed material, a so-called overcoat treatment in which the image surface of the printed material is covered with a protective layer (film) is known, and is also used for printed materials produced by an inkjet recording method. For example, in Patent Document 2, a supply mechanism for supplying a protective layer transfer sheet formed by forming a thermal transferable protective layer on a base film and a thermal transferable protective layer of the protective layer transfer sheet are formed by an ink jet method. An ink jet printer is disclosed that includes a thermal transfer mechanism for thermal transfer onto a printed image and a recovery mechanism for recovering a protective layer transfer sheet used for thermal transfer. In this printer, thermal transfer onto the image of the thermal transferable protective layer is performed by superimposing the protective layer transfer sheet on the image surface of the ink-jet print and heating and pressurizing them from the protective layer transfer sheet side with a heat roller. After the protective layer is heat-pressed on the image surface, the substrate film is recovered by a recovery mechanism.
JP 2001-63205 A Japanese Patent Laid-Open No. 2000-153677

  When the above-described resin-coated paper is used as a support and the overcoat treatment is performed using an existing overcoat apparatus, the transfer of the protective layer onto the image surface may be incomplete, or the inkjet recording may be performed. There has been a problem that the medium itself is deformed by heat and undulates.

  Therefore, an object of the present invention is to provide a protective layer for covering an image surface without causing inconvenience such as transfer layer transfer failure and recording medium undulation even for an ink jet recording medium having a resin-coated paper as a support. It is an object of the present invention to provide an image protection method that can be formed, and an overcoat device that is optimal for the implementation of the image protection method and has excellent operability.

  In order to achieve the above object, the image protection method of the present invention comprises an image protection method in which an image surface of a printed material on which a recording medium having an ink receiving layer on a resin-coated paper is printed by an inkjet recording method is covered with a protective layer. A thermal transfer film having a transfer layer that is releasably laminated on a support and the printed material are overlapped so that the transfer layer and the image surface face each other, and a space between a pair of heat rollers is provided. A thermocompression bonding step in which the transfer layer is thermocompression-bonded to the image surface by passing, and among the thermal rollers constituting the thermal roller pair, one of the thermal rollers in contact with the thermal transfer film in the thermocompression bonding step When the roller surface temperature is higher than the roller surface temperature of the other heat roller in contact with the printed material in the thermocompression bonding step, and the thickness of the printed material is 200 μm or more When the roller surface temperature of the heat roller pair is 90 to 120 ° C. and the thickness of the printed material is less than 200 μm, the roller surface temperature of the heat roller pair is the roller surface temperature when the thickness of the printed material is 200 μm or more. The temperature is lower than that of 80 to 105 ° C.

  According to the image protection method of the present invention, since the roller surface temperature of the heat roller pair used in the thermocompression bonding step is set to an appropriate range according to the thickness of the printed matter, the recording medium using the resin-coated paper as a support On the other hand, the protective layer can be formed without causing inconveniences such as transfer failure of the transfer layer and undulation of the recording medium, and a high quality photo-like overcoat printed matter can be obtained.

  Further, the overcoat apparatus of the present invention can be used for the implementation of an image protection method in which an image surface of a printed material on which a recording medium having an ink receiving layer on a resin-coated paper is printed by an inkjet recording method is covered with a protective layer. Film for superimposing a thermal transfer film having a transfer layer, which is releasably laminated on a support, on the image surface of the printed material so that the transfer layer and the image surface face each other A supply unit; a heated roller pair for heating and pressing the printed material and the thermal transfer film superimposed; and a peeling unit for peeling the support from the heated and pressed thermal transfer film. A plurality of overcoat processing modes having different temperatures are stored in advance, and one of these overcoat processing modes is selected based on the information on the printed matter. Wherein the are without the over preparative processing mode can be selected.

  According to the overcoat apparatus of the present invention, a processing mode suitable for the printed material can be selected from a plurality of overcoat processing modes prepared in advance. Can be formed on a recording medium using a resin-coated paper as a support without causing inconveniences such as transfer defect of the transfer layer and undulation of the recording medium. .

  Hereinafter, an image protection method and an overcoat apparatus of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of an embodiment of an overcoat apparatus according to the present invention, and FIG. 2 is a cross-sectional configuration diagram schematically showing a configuration of a main part of the overcoat apparatus shown in FIG. The overcoat apparatus 1 is an apparatus for forming a protective layer on an image surface of a printed material. The printed material P inserted from the insertion port 2 is an overcoated printed material OP whose image surface is coated with a protective layer. , Discharged from the discharge port 3. Reference numeral 4 denotes an operation panel of the apparatus, which is provided with a power ON / OFF switch, an overcoat mode switching switch, and the like. Reference numeral 5 denotes a display unit (display) that displays the state of the apparatus, the status of overcoat processing, and the like to the operator.

  The printed material P inserted from the insertion port 2 is placed between the thermal transfer film 71 supplied from the first film supply unit 7 and the under film 81 supplied from the second film supply unit 8 by the paper feed roller pair 6. Be transported. The thermal transfer film 71 is composed of a support and a transfer layer that is detachably laminated on the support and is thermally transferred onto the image surface of the printed material P. The film roll is wound around a film shaft 72 in a roll shape. The transfer layer is supplied so as to overlap the image surface of the printed matter P. Details of the thermal transfer film will be described later.

  The under film 81 mainly functions as a conveyance means for the printed material P and does not include a transfer layer. As the under film, one that does not adhere to the thermal transfer film 71 or the printed material P even after the next laminated sheet forming step is preferable. For example, a resin film such as polyethylene terephthalate (PET) or biaxially stretched polypropylene is used. Similarly to the thermal transfer film 71, the under film 81 is also wound into a film roll around a film shaft 82. When the film is supplied, the back surface of the printed matter P (on the opposite side to the image surface) is centered on the film shaft 82. ) So that they overlap.

  The printed matter P and the thermal transfer film 71 superimposed on the under film 81 are conveyed between the heat roller pair 9 as they are. The heat roller pair 9 is composed of an upper roller 91 and a lower roller 92, and each of the upper roller 91 and the lower roller 92 is a so-called heater (heating device) built in a hollow cylindrical metal or resin. It is a heat roller. The upper roller 91 and the lower roller 92 adjusted to a predetermined temperature are nipped with a predetermined nip pressure, and the printed matter P sandwiched between the thermal transfer film 71 and the under film 81 passes through the nip portion. The transfer layer of the thermal transfer film 71 is melted and softened and heat-pressed onto the image surface of the printed matter P, whereby a laminated sheet P ′ in which the printed matter P and the thermal transfer film 71 are integrated is obtained. In addition, as above-mentioned, the under film 81 is not crimped | bonded to the thermal transfer film 71 and the printed matter P by this thermocompression bonding process.

  Then, in the peeling part 10, the said support body is peeled from the lamination sheet P '. As a result, a protective layer composed of the transfer layer is formed on the image surface of the recorded matter P, and an overcoat printed matter OP is obtained. The peeled support is wound around the film shaft 101.

  The overcoat printed matter OP obtained in this way is discharged out of the apparatus from the discharge port 3 by the discharge roller pair 12. The under film 81 is wound around the film shaft 11 and collected.

  In the overcoat apparatus 1 of the present invention, a plurality of overcoat processing modes having different roller surface temperatures of the heat roller pair are stored in advance in the overcoat apparatus 1 configured as described above, and based on information on the printed matter P. An appropriate overcoat processing mode can be selected from the plurality of overcoat processing modes.

  In the overcoat apparatus of this embodiment, two types of overcoat processing modes (mode A and mode B) are stored in advance, and according to the thickness of the printed matter P (equal to the thickness of the recording medium before printing), The operator can select one of them. Mode A is an overcoat treatment mode selected when the thickness of the printed material is 200 μm or more, and the overcoat treatment is performed by setting the roller surface temperature of the heat roller pair 9 to 90 to 120 ° C. On the other hand, mode B is an overcoat treatment mode selected when the thickness of the printed material is less than 200 μm, and the overcoat treatment is performed by setting the roller surface temperature to 80 to 105 ° C. In mode A, the roller surface temperature is set higher than in mode B. Here, “roller surface temperature” means an average value of the roller surface temperatures of a plurality of rollers constituting the heat roller pair. Mode A and mode B differ only in the roller surface temperature of the heat roller pair 9, and the conveying speed, nip pressure, and other processing conditions are the same.

  In the present embodiment, among the heat rollers (the upper roller 91 and the lower roller 92) constituting the heat roller pair 9, the roller surface temperature of one upper roller 91 that is in contact with the heat transfer film 71 is in contact with the printed matter P. The temperature of the other lower roller 92 is set to be higher than the roller surface temperature. By making the heating conditions of the heat roller pair in this way, it becomes possible to further improve the transferability, and it is possible to more effectively prevent the undulation of the printed matter due to the heat of the lower roller. The roller surface temperature difference between the upper roller 91 and the lower roller 92 is preferably 5 to 60 ° C.

  The mode can be selected using the operation panel 4 provided on the outer surface of the overcoat apparatus 1. The operation panel 4 is provided with a mode changeover switch that can be switched between “for thick” (print thickness 200 μm or more) and “thin” (less than 200 μm for print thickness), and the operator switches to “thick”. Mode A is automatically selected, and mode B is automatically selected when the switch is switched to “for thin”. The display unit 5 displays the type of the selected mode, and displays that the preparation is complete when the roller surface temperature of the heat roller pair 9 reaches a predetermined set temperature.

  FIG. 3 is a block diagram showing a control configuration of the overcoat apparatus of the present embodiment shown in FIG. The control unit 20 controls the overcoat apparatus 1 as a whole, and is used as a ROM storing information necessary for processing executed by the CPU and a work area of the CPU in addition to a control processor centered on the CPU. It consists of RAM and the like. For example, when the operator sets the mode changeover switch of the operation panel 4 to “thick”, the control unit 20 sets the roller surfaces of the heat roller pair 9 to a predetermined temperature higher than that of the mode B in order to execute the mode A. Until the mode A is selected is displayed on the display unit 5. When the roller surface temperature of the heat roller pair 9 reaches a predetermined temperature, the display unit 5 displays that fact. The operator only has to insert the printed matter P to be overcoated from the insertion port 2 after seeing this display.

  In addition, in said embodiment, although the case where the printed matter P was a cut sheet shape of a suitable magnitude | size was described, the elongate continuous sheet by which the printed matter P was wound by roll shape may be sufficient. In this case, it is preferable to provide a cutter for cutting a long sheet between the heating and pressing unit 11 and the paper discharge roller pair 13.

  Next, the thermal transfer film according to the present invention will be described. The thermal transfer film includes a support and a transfer layer that is detachably laminated on the support.

  The support preferably has heat resistance that allows the shape to be stably maintained under predetermined thermocompression bonding conditions during thermal transfer, and can be easily peeled off from the transfer layer that is pressure-bonded on the image surface. Specifically, for example, polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP), polyethylene naphthalate (PEN), polyphenyl sulfide (PPS), polyether sulfone (PES), polystyrene (PS), polypropylene (PP Or the like can be used as the support.

  The thickness of the support may be set so as to obtain the above functions, and is not particularly limited.However, in consideration of thermal conductivity, adhesion, handling, prevention of air bubbles during overcoat, etc., preferably It is 8-60 micrometers, More preferably, it is 10-50 micrometers.

  On the other hand, the transfer layer laminated on the support is a layer that is thermally transferred onto the image surface of the printed material to become a protective layer. Examples of the material for forming the transfer layer include acrylic resin, acrylic-styrene resin, acrylic-urethane resin, polyvinyl acetal, vinyl acetate resin, vinyl chloride-vinyl acetate resin, and styrene resin. These resins may be used alone or in combination of two or more.

  The transfer layer may have a single layer structure composed of one kind of layer, but has various transfer properties, adhesion to an image surface, weather resistance when it becomes a protective layer, blocking resistance, scratch resistance, and the like. From the viewpoint of providing a good balance of properties, a multilayer structure in which two or more types of layers are laminated is preferable, and in particular, a two-layer structure including a surface protective layer and an adhesive layer in order from the support side is preferable. In this case, it is preferable that the surface protective layer has a glass transition temperature (Tg) higher than that of the adhesive layer, and the Tg difference between the two is preferably about 10 to 100 ° C.

  The Tg of the adhesive layer itself is preferably −20 to 60 ° C., more preferably −15 to 55 ° C. from the viewpoint of improving the adhesion to the image surface while maintaining the film forming properties necessary for the film. is there. On the other hand, the Tg of the surface protective layer itself is preferably 30 to 130 ° C., more preferably 35 to 125 ° C., from the viewpoint of improving blocking resistance and scratch resistance.

  For the transfer layer (surface protective layer, adhesive layer), if necessary, inorganic pigments such as silica, waxes, film-forming aids, ultraviolet absorbers, light stabilizers, antioxidants, water-proofing agents, preservatives Various additives such as a surfactant, a thickener, a fluidity improver, a pH adjuster, a leveling agent, and an antistatic agent can be added.

  The thickness of the transfer layer is preferably 2 to 50 μm, more preferably 5 to 30 μm. When the thickness of the transfer layer is less than 2 μm, the effect of protecting the image surface and the effect of improving glossiness are poor, and conversely, when the thickness exceeds 50 μm, the transparency may be lowered.

  When the transfer layer has a two-layer structure of a surface protective layer and an adhesive layer, the thickness of the surface protective layer is preferably 1 to 28 μm, and the thickness of the adhesive layer is preferably 2 to 29 μm.

  The transfer layer can be formed by coating a coating liquid prepared by mixing the layer forming material with an appropriate solvent as necessary, and drying the coating liquid on the support. The coating liquid can be applied by various coating methods such as a roll coating method, a rod bar coating method, and an air knife coating method.

  Next, the printed matter that is the target of the overcoat process will be described. The printed matter according to the present invention is only required to be able to adhere to the thermal transfer film having the above-described configuration. The present invention includes an inkjet recording method, an offset printing method, a gravure printing method, a sublimation transfer method, a melt transfer method, and an electrostatic toner recording. It can be applied to printed matter produced by a recording method such as a method. Among them, the one on which an image is printed by ejecting the pigment ink to the recording medium by the ink jet recording method (pigment ink jet printed matter) has a high effect of improving the image quality and storability by the overcoat treatment, and is a printed matter according to the present invention. Is optimal.

  Examples of the recording medium used as the base of the pigment ink-jet printed material include paper, coated paper, ink-jet recording medium, nonwoven fabric, various resin films, and the like. An ink jet recording medium in which an ink receiving layer is formed on at least one side of a resin-coated paper is preferable. The present invention is particularly effective for an inkjet recording medium based on this resin-coated paper, and a protective layer can be formed on the inkjet recording medium without causing adverse effects such as undulation due to thermal deformation. . Furthermore, when an image is printed with pigment ink, the present invention can greatly improve the abrasion resistance of the image, leading to an improvement in image density. Resin-coated paper (resin-coated paper) is a paper in which a resin layer such as polyethylene is provided on both sides of a base paper, and is excellent in water resistance. The ink receiving layer may be a so-called swelling type ink receiving layer containing a water-soluble resin such as polyvinyl alcohol or polyvinyl pyrrolidone as an essential component, or contains a pigment and a binder such as silica or alumina as an essential component. A so-called porous (void) type ink receiving layer may be used, but a porous type ink receiving layer is preferable.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention. However, the present invention is not limited to the examples.

(Manufacture of thermal transfer film)
A PET film (Lumirror S10, manufactured by Toray, thickness 23 μm) was used as a support, and a surface protective layer coating solution and an adhesive layer coating solution having the following composition were sequentially applied and dried on the entire surface of one side of this PET film. Then, a surface protective layer having a thickness of 4 μm and an adhesive layer having a thickness of 5 μm were laminated, and this was wound around a paper tube to produce a roll-shaped thermal transfer film.

<Composition of surface protective layer coating solution>
・ Movinyl 8020 47.6% by weight
(Colloidal silica-containing emulsion, manufactured by Clariant Polymer Co., Ltd., Tg-22 ° C)
・ Mobile 790 31.7% by weight
(Acrylic emulsion, Clariant Polymer Co., Ltd., Tg 102 ° C)
・ Snowtex 30 (Colloidal silica, manufactured by Nissan Chemical Co., Ltd.) 15.9% by weight
-Sunleaf CLA-3 (wax emulsion, manufactured by Sanyo Chemical Co., Ltd.) 3.8% by weight
・ Texanol (film forming aid, manufactured by Chisso Corporation) 1.0% by weight

<Composition of adhesive layer coating solution>
・ Mobile 727 99.0% by weight
(Acrylic emulsion, Clariant Polymer Co., Ltd., Tg16 ° C)
・ Texanol (film forming aid, manufactured by Chisso Corporation) 1.0% by weight

(Preparation of printed matter)
Using a pigment inkjet printer (PM-4000PX, manufactured by Seiko Epson), a high-definition color digital standard image [(ISO / JIS-SCID), image name “portrait” (sample number 1, image Evaluation recognition number N1)] was printed in the “recommended clean mode” to produce a printed matter without blurring or disturbance of the image. As the recording medium, the following two types (recording medium A and recording medium B) using resin-coated paper as a support were used.
Recording medium A (thick): trade name “Photo Paper (Glossy)”, manufactured by Seiko Epson, thickness 260 μm
Recording medium B (thin): trade name “MC photo paper roll”, manufactured by Seiko Epson, thickness 165 μm

[Examples 1-4 and Comparative Examples 1-2]
The roll-shaped thermal transfer film produced as described above was set in the overcoat apparatus having the configuration shown in FIGS. 1 and 2, and a PET film having a thickness of 23 μm was set as the under film. And the said printed matter was inserted in this overcoat apparatus, the overcoat process was performed with respect to this printed matter, and the overcoat printed matter was produced. The conveyance speed of the printed material was 15 mm / s, and the nip pressure between the upper roller 91 and the lower roller 92 in the heat roller pair 9 was 10 kg / cm ² .

[Test example]
The overcoat printed matter produced as described above was evaluated for the transferability of the transfer layer and the degree of undulation of the overcoat printed matter. These results are shown in the following [Table 1].

<Method for evaluating transferability>
Observe the surface of the protective layer of the overcoat print visually, A (no transfer or good transfer layer) where no blur or distortion of the image is observed, a slight blur or distortion of the image is observed, but there is no practical problem B, and C was the one that could not be put to practical use due to severe blurring and disturbance of the image. In addition, “bleeding or disturbance of the image” seen in the overcoat printed matter is a transfer layer (protective layer) that should adhere to the printed material when the support is peeled off from the thermal transfer film pressed onto the printed material in the overcoat treatment. ) Is partly or entirely peeled off together with the support or is likely to peel off. Therefore, the more the transfer layer adheres firmly to the printed material and does not peel off together with the support when the support is peeled off, that is, the transfer layer is excellent in transferability onto the printed material. "Less is.

<Evaluation method of undulation>
The overcoat printed matter was visually observed, and A was given when the printed matter was flat with no wavy phenomenon, B was given what could be seen but could withstand the appreciation, and C was given with a wave that was so unbearable.

It is a perspective view of one embodiment of the overcoat device of the present invention. It is a cross-sectional block diagram which shows typically the structure of the principal part of the overcoat apparatus shown in FIG. It is a block diagram which shows the control structure of the overcoat apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Overcoat apparatus, 2 ... Insertion port, 3 ... Discharge port, 4 ... Operation panel, 5 ... Display part, 6 ... Paper feed roller pair, 7 ... 1st film supply part, 71 ... Thermal transfer film, 72 ... Film axis 8 ... 2nd film supply part, 81 ... Under film, 82 ... Film axis, 9 ... Heat roller pair, 91 ... Upper roller, 92 ... Lower roller, 10 ... Peeling part, 101 ... Film axis, 11 ... Film axis, 12 ... Discharge roller pair, 20 ... Control unit, P ... Printed matter, P '... Laminated sheet, OP ... Overcoat printed matter

Claims (5)

An image protection method in which an image surface of a printed material on which an image is printed on a recording medium having an ink receiving layer on a resin-coated paper by an inkjet recording method is covered with a protective layer,
By superimposing a thermal transfer film having a transfer layer releasably laminated on a support and the printed matter so that the transfer layer and the image surface face each other, and passing between a pair of heat rollers, A thermocompression bonding step of thermocompression bonding the transfer layer to the image surface;
Among the heat rollers that constitute the heat roller pair, the temperature of the surface of one heat roller that contacts the thermal transfer film in the heat pressure bonding step is the roller surface temperature of the other heat roller that contacts the printed matter in the heat pressure bonding step. Higher than the temperature,
When the thickness of the printed material is 200 μm or more, the roller surface temperature of the heat roller pair is 90 to 120 ° C., and when the thickness of the printed material is less than 200 μm, the roller surface temperature of the heat roller pair is the thickness of the printed material. An image protection method, wherein the temperature is lower than the roller surface temperature and the temperature is 80 to 105 ° C. when the thickness is 200 μm or more.   2. The image protection method according to claim 1, wherein the printed material is an image printed with pigment ink. An overcoat apparatus that can be used for carrying out an image protection method for covering an image surface of a printed material on which an image is printed on a recording medium having an ink receiving layer on a resin-coated paper by an inkjet recording method, with a protective layer,
A film supply unit that superimposes a thermal transfer film having a transfer layer detachably laminated on a support on the image surface of the printed material so that the transfer layer and the image surface face each other, and the superimposed film supply unit A heat roller pair for heating and pressing the printed matter and the thermal transfer film, and a peeling portion for peeling the support from the heat-pressed thermal transfer film,
At least a plurality of overcoat processing modes having different roller surface temperatures of the heat roller pair are stored in advance, and one overcoat processing mode can be selected from these based on information on the printed matter. An overcoat device characterized by.   As the plurality of overcoat processing modes, the mode A in which the roller surface temperature of the heat roller pair is set to 90 to 120 ° C., and the roller surface temperature of the heat roller pair is lower than the roller surface temperature in the mode A. Mode B set to 80 to 105 ° C. is stored in advance. When the thickness of the printed material is 200 μm or more, the mode A is selected. When the thickness of the printed material is less than 200 μm, the mode B is selected. The overcoat apparatus according to claim 3, wherein the overcoat apparatus is configured as described above. Among the heat rollers constituting the heat roller pair, the roller surface temperature of one heat roller in contact with the heat transfer film is set to be higher than the roller surface temperature of the other heat roller in contact with the printed matter. The overcoat apparatus according to claim 3 or 4, characterized in that:

Images