JP2015160391A - Printer and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer capable of stably discharging an ink, and to provide a printing method.SOLUTION: A printer includes: a droplet discharge head 23 which discharges an ink to a recording medium 100; moving means which reciprocates the droplet discharge head 23; heating members 7A, 7B provided at heating regions 300, 400 located at the outer side of a printing region 200 where the droplet discharge head 23 discharges the ink while moving; and a control part. The control part controls the heating members 7A, 7B so that temperatures of the heating regions 300, 400 become higher than that of the printing region 200.

Description

  The present invention relates to a printing apparatus and a printing method.

  2. Description of the Related Art Conventionally, a printing apparatus that prints by applying ink on a flexible sheet-like recording medium has been used (see, for example, Patent Document 1). A printing apparatus described in Patent Document 1 includes a transport mechanism that transports a recording medium, a head unit that ejects ink onto the transported recording medium, a platen that supports the recording medium in a printing region to which ink is applied, And a moving mechanism for reciprocating the head unit with respect to the recording medium.

  In such a printing apparatus, the head unit passes on the platen (printing area) while ejecting ink in the forward path, and then temporarily moves to the first area outside the printing area. In the return path, the head unit moves from the first position to the second region opposite to the first region through the platen while ejecting ink again. By repeating such movement, the head unit performs printing on the recording medium while reciprocating.

Here, although the ink ejected from the head unit depends on its composition, the viscosity decreases when the temperature is higher than a desired temperature (for example, about 30 to 60 ° C.), and the viscosity decreases when the temperature is lower than the desired temperature. Get higher. Therefore, in order to print on a recording medium with high accuracy, it is preferable that the temperature of ink when ejected is kept constant at a desired temperature.
However, when the head unit is moving in the printing area, the first area, and the second area, the temperature of the head unit may decrease. In this case, the viscosity of the ink ejected from the head unit increases, and the ejection may become unstable.

JP 2002-178492 A

  An object of the present invention is to provide a printing apparatus and a printing method capable of stably ejecting ink.

Such an object is achieved by the present invention described below.
[Application Example 1]
A printing apparatus according to the present invention includes an ejection unit that ejects ink onto a recording medium;
A moving part for reciprocating the discharge part;
A heating unit provided in an outer region outside a printing region that ejects the ink while the ejection unit is moved by the operation of the moving unit;
A controller that controls the discharge unit, the moving unit, and the heating unit;
The control unit controls the heating unit so that the outer region has a higher temperature than the printing region.
Thereby, a discharge part can be heated in an outer side area | region. Therefore, the ejection unit can eject ink stably.

[Application Example 2]
In the printing apparatus of the present invention, at least a part of the outer region is an acceleration / deceleration region in which the discharge unit accelerates or decelerates,
The heating unit is preferably provided in the acceleration / deceleration region.
Thereby, it is possible to omit providing an acceleration region separately outside the outer region.

[Application Example 3]
In the printing apparatus according to the aspect of the invention, it is preferable to include a temperature detection unit that detects the temperature of the ejection unit.
Thereby, the temperature of a discharge part is detectable.

[Application Example 4]
In the printing apparatus according to the aspect of the invention, the control unit controls the moving unit so that the discharge unit reciprocates within the print region, and the temperature of the discharge unit detected by the temperature detection unit falls below a threshold value. In some cases, it is preferable that the discharge unit is moved to the outer region to heat the discharge unit.
Thereby, while being able to heat a discharge part reliably, printing can be performed efficiently.

[Application Example 5]
In the printing apparatus according to the aspect of the invention, the control unit controls the moving unit so that the discharge unit passes through the print region and the outer region in both the outward path and the return path, and the discharge detected by the temperature detection unit. When the temperature of the part exceeds the threshold value, the temperature of the heating part is preferably lowered.
Thereby, it can prevent that a heating part is heated too much.

[Application Example 6]
In the printing apparatus according to the aspect of the invention, it is preferable that the control unit adjusts the temperature of the heating unit in accordance with a moving speed of the discharge unit in the outer region.
Thereby, the discharge part can be heated regardless of the moving speed.

[Application Example 7]
In the printing apparatus according to the aspect of the invention, it is preferable that the control unit adjusts the temperature of the heating unit according to a separation distance between the heating unit and the discharge unit when the discharge unit passes over the heating unit. .
Thereby, the discharge part can be heated regardless of the separation distance between the heating part and the discharge part.

[Application Example 8]
In the printing apparatus of the present invention, the discharge unit has a discharge number detection unit that detects the number of discharges of discharging the ink,
Preferably, the control unit adjusts the temperature of the heating unit based on the number of ejections detected by the ejection number detection unit.
Thereby, the discharge part can be heated according to the number of ink discharges of the discharge part.

[Application Example 9]
In the printing apparatus according to the aspect of the invention, it is preferable that a pair of the heating units is provided via the printing region.
As a result, the discharge unit can be heated more effectively because the pair of heating units are provided.

[Application Example 10]
The printing method of the present invention includes an ejection unit that ejects ink onto a recording medium;
A moving part for reciprocating the discharge part;
A printing apparatus comprising a heating unit provided in an outer region outside a printing region that ejects the ink while the ejection unit is moved by the operation of the moving unit, and printing on the recording medium,
The outer region has a higher temperature than the printing region.
Thereby, a discharge part can be heated in an outer side area | region. Therefore, the ejection unit can eject ink stably.

FIG. 1 is a perspective view showing a first embodiment of a printing apparatus according to the present invention. 2 is a cross-sectional view (schematic cross-sectional surface) taken along line AA in FIG. FIG. 3 is a block diagram of the printing apparatus shown in FIG. 4A is a diagram illustrating the moving speed of the ejection unit included in the printing apparatus illustrated in FIG. 1, and FIG. 4B is a schematic diagram viewed from the direction of arrow B in FIG. 5A and 5B are graphs showing the relationship between the temperature of the discharge section and time. FIG. 6 is a block diagram showing a second embodiment of the printing apparatus of the present invention. FIG. 7 is a flowchart showing the operation of the control unit shown in FIG. FIG. 8 is a schematic front view showing a third embodiment of the printing apparatus of the present invention, where (a) is a diagram showing a state in which the ejection unit is reciprocating in the printing region, and (b) is an ejection It is a figure which shows the state which the part moved to the heating area | region. FIG. 9 is a graph showing the relationship between the voltage E applied to the heating element of the heating unit and the moving speed of the discharge unit in the fourth embodiment of the printing apparatus of the present invention. FIG. 10 is a graph showing the relationship between the voltage E applied to the heating element of the heating unit and the separation distance between the ejection unit and the heating unit in the fifth embodiment of the printing apparatus of the present invention. FIG. 11 is a graph showing the relationship between the voltage E applied to the heating element of the heating unit and the number of ejections that the ejection unit ejects ink in the sixth embodiment of the printing apparatus of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a printing apparatus of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
<First Embodiment>
FIG. 1 is a perspective view showing a first embodiment of a printing apparatus according to the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 (schematic cross-sectional view), and FIG. 3 is a printing apparatus shown in FIG. FIG. 4 is a block diagram of FIG. 4, (a) is a diagram showing the moving speed of the discharge section provided in the printing apparatus shown in FIG. 1, (b) is a schematic view seen from the direction of arrow B in FIG. 2, FIG. (A) And (b) is a graph which shows the relationship between the temperature of a discharge part, and time.

In the following, for convenience of explanation, in FIGS. 1, 2, and 4 (the same applies to FIG. 7), the x axis, the y axis, and the z axis are illustrated as three axes orthogonal to each other. The x-axis is an axis along one of the horizontal directions (the width (depth) direction of the printing apparatus), and the y-axis is a horizontal direction perpendicular to the x-axis (the length of the printing apparatus). Direction), and the z-axis is an axis along the vertical direction (vertical direction). In addition, the tip side of each illustrated arrow is a “positive side (+ side)” and the base end side is a “negative side (− side)”. 1 to 3 (the same applies to FIG. 6), the upper side is referred to as “upper (upper)”, and the lower side is referred to as “lower (lower)”.
As shown in FIG. 1, a printing apparatus (printing apparatus of the present invention) 1 executes the printing method of the present invention, and includes an apparatus main body 2, a leg (stand) 3, a curing unit 4, and a control. Part 8. The printing apparatus 1 is an apparatus that performs color printing by applying ink onto the recording medium 100 by an inkjet method.

Hereinafter, the configuration of each unit will be described.
First, the ink and the recording medium 100 will be described.
The ink used for printing is a so-called “latex ink” and is loaded in the printing apparatus 1 as an ink set (cartridge), and the ink set includes a first ink and a second ink having a predetermined composition, and Any one of predetermined (A) and (B) described later is satisfied.

The first ink contains a color material, resin particles, a first humectant, and an aprotic polar solvent.
The second ink includes a coloring material in an amount exceeding the content of the coloring material contained in the first ink, a resin particle in an amount less than the content of the resin particles contained in the first ink, a second humectant, and Contains an aprotic polar solvent.

On the other hand, both the first ink and the second ink substantially contain no alkyl polyol having a boiling point of 280 ° C. or higher. Thereby, the load of a drying process can be reduced.
Here, “substantially not containing” means not containing, for example, 1.0% by mass or more, preferably 0.5% by mass or more, with respect to the total mass (100% by mass) of the ink. More preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less. The most preferable content is 0.001% by mass or less.

  The ink set preferably includes the first ink and the second ink. However, in addition to the first ink and the second ink, the ink set may further include another ink different from these inks. In addition to the first ink and the second ink, when other ink different from these inks is further included, the other ink may contain an alkyl polyol having a boiling point of 280 ° C. or higher.

Hereinafter, additives (components) that are or can be included in each ink (ink composition) constituting the ink set will be described.
Hereinafter, when the ink further includes the first ink, the second ink, and other inks different from these inks, the other inks may be collectively referred to as “ink”.

Unless otherwise specified, each component contained in the first ink and each component contained in the second ink are selected independently from each other in terms of type, physical properties, content, and the like. Further, not only when the first ink and the second ink included in one ink set are each composed of a single type, but also when there are a plurality of types of the first ink and a plurality of types of the second ink. Similarly to the above, the type of each component contained in each ink, its physical properties, the content, and the like are selected independently of each other.
Further, when there are a plurality of types of first inks included in one ink set, the “content of the first ink” means an average value of the contents in the respective first inks. The same applies when there are a plurality of types of second ink.

[Humectant]
Both the first ink and the second ink included in the ink set contain a humectant. Here, “first humectant” in the present specification means a humectant contained in the first ink, and “second humectant” in the present specification means a humectant contained in the second ink. . The first humectant and the second humectant have a correlation that satisfies either of the conditions (A) or (B). Below, it demonstrates for every conditions of (A) and (B).

  First, the condition (A) will be described. In (A), the first humectant is (a1) 1,2-alkanediol and a solvent other than 1,2-alkanediol, or (a2) other than 1,2-alkanediol. It is a solvent. In addition, the boiling point of the solvent other than the 1,2-alkanediol in the first humectant is 200 ° C. or more and 260 ° C. or less. That is, the first humectant essentially includes a solvent other than 1,2-alkanediol having a predetermined boiling point regardless of whether or not it contains 1,2-alkanediol.

When the boiling point of the first humectant is 160 ° C. or higher, the intermittent printing characteristics are excellent. On the other hand, when the boiling point of the first humectant is 260 ° C. or less, glycerin or the like is not added, so that quick drying is good and the recorded material has excellent abrasion resistance.
The solvent other than the 1,2-alkanediol as the first humectant is not particularly limited as long as the boiling point is 200 ° C. or higher and 260 ° C. or lower. For example, glycol ethers, 1, α-alkanediol (however, , Α = 2 is excluded).

  Examples of the glycol ethers include, but are not limited to, polyalkylene glycols such as diethylene glycol, dipropylene glycol, and dibutylene glycol. The 1, α-alkanediol (excluding α = 2) is not limited to the following, but examples include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 7-heptanediol. The alkylene glycol monoether contained in the polyalkylene glycols includes ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol Monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether and the like. Examples of the alkylene glycol diether contained in the polyalkylene glycols include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether. , Triethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, and Dipropylene glycol diethyl ether. Among the glycol ethers, polyalkylene glycols are preferable because they have excellent moisture retention.

Among these, at least one selected from glycol ethers and 1, α-alkanediol (except α = 2) is preferable because appropriate moisture retention can be imparted.
When the first humectant is (a1) 1,2-alkanediol and a solvent other than the 1,2-alkanediol, in the first ink, the total content of the first humectant and the aprotic described later The mass ratio to the content of the polar solvent (“total content of the first humectant”: “content of the aprotic polar solvent”) is preferably 0.6 to 2.6. When the mass ratio is within the above range, the adhesiveness is excellent.
In (A) above, the condition that the boiling point of the first humectant exceeds the boiling point of the second humectant is also satisfied. In the present specification, the “boiling point of the first humectant” means an average value of boiling points of the two or more solvents when the first humectant is composed of two or more solvents. The same applies to the “boiling point of the humectant”.

  Assuming that the condition is satisfied, the second humectant is (a3) 1,2-alkanediol and a solvent other than 1,2-alkanediol, or (a4) the 1,2-alkane. Solvent other than diol. In addition, the boiling point of the solvent other than the 1,2-alkanediol in the second humectant is preferably 160 ° C. or higher and 240 ° C. or lower. That is, the second moisturizing agent may be 1,2-alkanediol, but whether or not it contains 1,2-alkanediol, other than 1,2-alkanediol having a predetermined boiling point. It is preferable to include a solvent.

When the boiling point of the second humectant is 160 ° C. or higher, the intermittent printing characteristics are excellent. On the other hand, when the boiling point of the second humectant is 240 ° C. or less, the drying load can be effectively reduced.
The solvent other than the above-described 1,2-alkanediol as the second humectant is not particularly limited as long as the boiling point is 160 ° C. or higher and 240 ° C. or lower and lower than the boiling point of the first humectant. Since it is excellent, glycol ethers are preferable.
Next, the condition (B) will be described. The first humectant and the second humectant are both dipropylene glycol. In addition, the content of dipropylene glycol contained in the first ink exceeds the content of dipropylene glycol contained in the second ink.

The content of dipropylene glycol contained in the first ink is preferably 3 to 30% by mass and more preferably 5 to 15% by mass with respect to the total mass (100% by mass) of the first ink. On the other hand, the content of dipropylene glycol contained in the second ink is preferably 3 to 30% by mass, and more preferably 5 to 15% by mass. When each content of dipropylene glycol contained in the first ink and the second ink is within the above range, the drying load can be effectively reduced.
In addition, when the ink set further includes another ink different from the first ink and the second ink, the other ink may contain the above-described moisturizing agent.

[Color material]
The first ink and the second ink included in the ink set contain a color material. The color material is selected from pigments and dyes.
(1. Pigment)
Of the above color materials, the pigment is not only insoluble or hardly soluble in water, but also has a property of hardly fading to light or gas. Therefore, a recorded matter recorded with an ink using a pigment has good water resistance, gas resistance, light resistance, and storage stability.

As the pigment, any of inorganic pigments and organic pigments can be used. Among these, at least one of carbon black and organic pigments belonging to the inorganic pigment is preferable because it has good color developability and is difficult to settle during dispersion because of its low specific gravity.
Although it does not specifically limit as an inorganic pigment, For example, carbon black, iron oxide, and a titanium oxide are mentioned.

  Although it does not specifically limit as said carbon black, For example, furnace black, lamp black, acetylene black, and channel black (CI pigment black 7) are mentioned. Further, as a commercially available product of carbon black, for example, No. 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all trade names, manufactured by Mitsubishi Chemical Corporation), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U, Special Black 6, 5, 4A, 4, 250 (all trade names, manufactured by Degussa AG), CONDUCTEX SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700 (all trade names, Columbia Carbon ( Columbian Carbon Japan Ltd), Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 (all trade names, Cabot Corporation) Manufactured).

  Examples of organic pigments include, but are not limited to, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, Examples include perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. . Specific examples of the organic pigment include the following.

Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat Blue 4 and 60 are listed.
Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50.

Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213.
In addition, as a pigment used for inks of colors other than the above, such as green ink and orange ink, conventionally known pigments can be used.
A pigment may be used individually by 1 type and may be used in combination of 2 or more type.

(2. Dye)
Although it does not limit to the following as a dye among the said color materials, For example, an acidic dye, a direct dye, a reactive dye, and a basic dye are mentioned. Specific examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

A dye may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the color material contained in the second ink is greater than the content of the color material contained in the first ink. The first ink and the second ink can be referred to as light ink and dark ink, respectively, from the viewpoint of the amount of the color material.
The content of the color material contained in the first ink is preferably 1 to 7% by mass with respect to the total mass (100% by mass) of the first ink. In addition, the content of the color material contained in the second ink is preferably 0.1 to 2% by mass with respect to the total mass (100% by mass) of the second ink.
When the ink set further includes another ink different from the first ink and the second ink, the other ink may contain the above-described color material.

[Resin particles]
The first ink and the second ink included in the ink set contain resin particles. When the first ink and the second ink contain resin particles, the recorded article has excellent abrasion resistance.
Further, the content of the resin particles contained in the second ink is smaller than the content of the resin particles contained in the first ink. Thereby, the viscosity of each ink which comprises an ink set can be equalized. Each content of the resin particles contained in the first ink and the second ink will be described later.
Examples of the resin particles include, but are not limited to, binder resins and waxes such as paraffin wax and polyolefin wax.

(1. Binder resin)
The binder resin exhibits the effect of improving the abrasion resistance of the recorded matter by sufficiently fixing the ink onto the recording medium 100 by forming a resin film when the recording medium 100 is heated in ink jet recording. To do. Therefore, the binder resin is preferably a thermoplastic resin. Due to the effects described above, a recorded matter recorded using an ink containing a binder resin is more excellent in abrasion resistance on the non-ink-absorbing and low-absorbing recording medium 100.

The binder resin is contained in the ink in an emulsion state. By including the binder resin in the ink in an emulsion state, the viscosity of the ink can be easily adjusted to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink are excellent.
In the present specification, “ejection stability” refers to a property of ejecting a stable ink droplet from the nozzle without clogging of the nozzle.

Examples of the binder resin include, but are not limited to, (meth) acrylic acid, (meth) acrylic ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone. , Vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride homopolymers or copolymers, fluororesins, and natural resins. Among them, at least one of (meth) acrylic resin and styrene- (meth) acrylic acid copolymer resin is preferable, and at least one of acrylic resin and styrene-acrylic acid copolymer resin is more preferable, styrene. -Acrylic acid copolymer resin is more preferable. In addition, said copolymer may be any form among a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.
In the present specification, “(meth) acryl” means at least one of acrylic and methacryl corresponding thereto.

  As said binder resin, what is obtained by a well-known material and a manufacturing method may be used, and a commercial item may be used. The commercially available products are not limited to the following, but include, for example, Microgel E-1002, Microgel E-5002 (trade names, manufactured by Nippon Paint Co., Ltd.), Boncourt 4001, Boncourt 5454 ( Product name, manufactured by DIC, SAE1014 (trade name, manufactured by Zeon Corporation), Cybinol SK-200 (trade name, manufactured by SAIDEN CHEMICAL INDUSTRY CO., LTD.), Jonkrill 7100, John Crill 390, John Crill 711, John Crill 511, John Crill 7001, John Crill 632, John Crill 741, John Crill 450, John Crill 840, John Crill 74J, John Crill HRC-1645J, John Crill 734, John Crill 852, Jongkrill 7600, Jongkuri 775, John Crill 537J, John Crill 1535, John Crill PDX-7630A, John Crill 352J, John Crill 352D, John Crill PDX-7145, John Crill 538J, John Crill 7640, John Crill 7641, John Crill 631, John Crill 790 , Jonkrill 780, Jonkrill 7610 (trade name, manufactured by BASF) and the like.

  Although said binder resin is not specifically limited, For example, it can obtain by the preparation method shown below, You may combine a some method as needed. As the preparation method, a polymerization catalyst (polymerization initiator) and a dispersant are mixed in a monomer of a component constituting a desired resin, and polymerization (emulsion polymerization) is performed. A resin having a hydrophilic portion is dissolved in water. A method of removing a water-soluble organic solvent by distillation after mixing a solution obtained by dissolving in a water-soluble organic solvent into water, and a solution obtained by dissolving a resin in a water-insoluble organic solvent together with a dispersant in an aqueous solution The method of mixing is mentioned.

  The dispersant that can be used when dispersing the binder resin in the emulsion state is not particularly limited, but examples include anions such as sodium dodecylbenzenesulfonate, sodium lauryl phosphate, and polyoxyethylene alkyl ether sulfate ammonium salt. And nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene alkylphenyl ethers. These dispersants may be used alone or in combination of two or more.

The average particle size of the binder resin is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink.
Here, the average particle diameter in this specification shall be shown by the value measured by the dynamic light scattering method.
The content of the binder resin that can be contained in each ink (in terms of solid content) is preferably in the range of 0.5 to 5% by mass with respect to the total mass (100% by mass) of the ink, and is preferably 0.5 to 1.5%. A range of mass% is more preferred. When the content is within the above range, the abrasion resistance is further improved.

(2. Paraffin wax)
When the ink in the present embodiment contains paraffin wax, slip performance is imparted to the recorded matter, whereby the ink is further excellent in abrasion resistance. In addition, since paraffin wax has water repellency, the water resistance of the recorded matter can be improved.

The “paraffin wax” in the present specification means a so-called petroleum wax, which is mainly composed of a linear paraffinic hydrocarbon (normal paraffin) having about 20 to 30 carbon atoms and a small amount of iso (iso). -It means a mixture of hydrocarbons containing paraffin and having a weight average molecular weight of about 300 to 500.
When the ink in the present embodiment contains paraffin wax in an emulsion state, it is easy to adjust the viscosity of the ink to an appropriate range in the ink jet recording method, and the storage stability and ejection stability of the ink are further improved. can do.

  The melting point of the paraffin wax is preferably 110 ° C. or lower in order to further strengthen the film of the recorded material and further improve the abrasion resistance of the recorded material. On the other hand, the lower limit of the melting point of the paraffin wax is preferably 60 ° C. or higher in order to prevent the recording surface from being dried and sticky. Further, the melting point is more preferably 70 to 95 ° C. in order to further improve the ink ejection stability.

The average particle diameter of the paraffin wax is preferably in the range of 5 nm to 400 nm, more preferably 50 nm to 200 nm, in order to obtain a stable emulsion state and to further improve the storage stability and ejection stability of the ink. It is a range. A commercially available product may be used as it is as the paraffin wax. Examples of the commercially available products include, but are not limited to, AQUACER 537, AQUACER 539 (trade names, manufactured by BYK).
The content (in terms of solid content) of the paraffin wax that can be contained in each ink is preferably in the range of 0 to 1.5% by mass with respect to the total mass (100% by mass) of the ink, and is preferably 0.25 to 0.75. A range of mass% is more preferred.

(3. Polyolefin wax)
When the ink in the present embodiment contains a polyolefin wax, it is possible to further improve the abrasion resistance of the recorded matter. Examples of the polyolefin wax include, but are not limited to, polyethylene wax and polypropylene wax. Among these, polyethylene wax is preferable.

  For example, the polyethylene wax is produced by polymerizing ethylene, or by producing polyethylene for general molding by reducing the molecular weight by thermal decomposition. Then, the polyethylene wax is oxidized to add a carboxyl group or a hydroxyl group, and is further emulsified using a surfactant to obtain a polyethylene wax in the form of an aqueous emulsion having excellent stability.

  A commercially available product may be used as it is as the polyolefin wax. Among these, commercially available products of polyethylene wax are not limited to the following. For example, Nopcoat PEM17 (trade name, manufactured by SANNOPCO LIMITED), Chemipearl W4005 (trade name, manufactured by Mitsui Chemicals, Inc.) ), AQUACER 515, AQUACER 593 (trade name, manufactured by BYK).

The average particle diameter of the polyolefin wax is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.
The polyolefin wax content (in terms of solid content) that can be contained in each ink is preferably in the range of 0 to 1.5% by mass, preferably 0.25 to 0.75, relative to the total mass (100% by mass) of the ink. A range of mass% is more preferred.
Among those described so far, the resin particles are preferably at least one of a polyolefin wax and a paraffin wax in order to further improve the abrasion resistance of the recorded matter.

Each ink may contain wax other than polyolefin wax and paraffin wax as resin particles. The wax has a function of imparting slip performance to the surface of the formed recorded matter and improving the abrasion resistance. The wax is preferably contained in the ink in an emulsion state. Since the wax in the ink exists in an emulsion state, the viscosity of the ink can be easily adjusted to an appropriate range in the ink jet recording method, and the storage stability and ejection stability of the ink can be further improved. .
In addition, when the ink set further includes another ink different from the first ink and the second ink, the other ink may contain the above-described resin particles.

[Aprotic polar solvent]
The first ink and the second ink included in the ink set contain an aprotic polar solvent. When the first ink and the second ink contain an aprotic polar solvent, the above-described resin particles contained in these inks are dissolved, so that nozzle clogging is effectively prevented during ink jet recording. can do.
The aprotic polar solvent contained in the first ink and the second ink may be the same component.

The aprotic polar solvent is not limited to the following, but from the group consisting of pyrrolidones, lactones, sulfoxides, imidazolidinones, sulfolanes, urea derivatives, dialkylamides, cyclic ethers, and amide ethers. It is preferable to include one or more selected.
Specific examples of the pyrrolidones include 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. Specific examples of the lactones include γ-butyrolactone, γ-valerolactone, and ε-caprolactone. Specific examples of the sulfoxides include dimethyl sulfoxide and tetramethylene sulfoxide. Specific examples of the imidazolidinones include 1,3-dimethyl-2-imidazolidinone. Specific examples of the sulfolanes include sulfolane and dimethyl sulfolane. Specific examples of the urea derivative include dimethylurea and 1,1,3,3-tetramethylurea. Specific examples of the dialkylamides include dimethylformamide and dimethylacetamide. Specific examples of the cyclic ethers include 1,4-dioxane and tetrahydrofuran.
Moreover, as said amide ether, the solvent shown by following General formula (1) corresponds.

In the above formula (1), R ¹ is preferably an alkyl group having 1 to 4 carbon atoms. The “C1-C4 alkyl group” may be a linear or branched alkyl group, such as a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, It may be an iso-butyl group, a sec-butyl group, or a tert-butyl group. The solvent represented by the formula (1) in which R ¹ is an alkyl group having 1 to 4 carbon atoms can impart appropriate pseudoplasticity to the ink composition, thereby ensuring good ejection stability of the ink. Can do. In addition, the solvent represented by the formula (1) in which R ¹ is an alkyl group having 1 to 4 carbon atoms is preferable because the resin dissolving action is particularly strong.

The HLB value of the solvent represented by the above formula (1) is preferably 10.5 or more and 20.0 or less, more preferably 12.0 or more and 18.5 or less. When the HLB value of the solvent represented by the formula (1) is within the above range, it is more preferable from the viewpoint of imparting appropriate pseudoplasticity to the ink and interaction with the resin component.
The HLB value of the solvent represented by the formula (1) is based on the ratio between the nonpolar value (I) and the organic value (O) in the organic conceptual diagram (hereinafter also simply referred to as “I / O value”). It is a value calculated by the following formula.
HLB value = (Nonpolar value (I) / Organic value (O)) × 10

Specifically, the I / O values are as follows: “Systematic Organic Qualitative Analysis Mixture” (Fujita Atsushi, Kazama Shobo, 1974), “Dyeing Theory Chemistry” (Kuroki Nobuhiko, Sakai Shoten, 1966), “ It can be calculated based on each document of “Organic Compound Separation Method” (Hiroo Inoue, Soukabo, 1990).
Among these aprotic polar solvents, one or more selected from the group consisting of pyrrolidones, lactones, sulfoxides, and amide ethers is more preferable because the fixability to the recording medium 100 is excellent.

The boiling point of the aprotic polar solvent is preferably 200 ° C. or higher and 260 ° C. or lower.
Specific examples of the aprotic polar solvent are not limited to the following, but 2-pyrrolidinone is preferably used.
The aprotic polar solvent contained in each of the first ink and the second ink may be used alone or in combination of two or more.

The content of the aprotic polar solvent contained in each of the first ink and the second ink is preferably in the range of 3 to 30% by mass, and 8 to 20% by mass with respect to the total mass (100% by mass) of the ink. % Range is more preferred.
When the ink set further includes another ink different from the first ink and the second ink, the other ink may contain the above-mentioned aprotic polar solvent.

[Surfactant]
Each ink included in the ink set may contain a surfactant. Examples of other surfactants include, but are not limited to, nonionic surfactants. The nonionic surfactant has an action of spreading the ink uniformly on the recording medium 100. Therefore, when ink jet recording is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be obtained. Examples of such nonionic surfactants include, but are not limited to, acetylene glycol surfactants, silicon surfactants, polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, and polycyclic phenyl ethers. System, sorbitan derivatives, and fluorosurfactants.
Surfactant may be used individually by 1 type and may use 2 or more types together.
The content of the surfactant that can be contained in each ink may be in the range of 1.5% by mass or less with respect to the total mass (100% by mass) of the ink.

[water]
Each ink included in the ink set may contain water. In particular, when the ink is a water-based ink, water is a main medium of the ink, and becomes a component that evaporates and scatters when the recording medium 100 is heated in ink jet recording.
Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the pigment dispersion and ink using the same are stored for a long period of time.

[Other ingredients]
Each ink included in the ink set may further contain, in addition to the above components, an organic solvent other than the above, a pH adjuster, an antiseptic / fungicide, a rust inhibitor, a chelating agent, and the like.
The recording medium 100 to which ink is applied has flexibility and is loaded into the printing apparatus 1 in a state of being wound in a roll shape. This recording medium 100 is suitable not only for ink-absorbing recording media but also for ink-jet recording using non-ink-absorbing and low-absorbing recording media.

  Examples of the ink-absorbing recording medium 100 include, but are not limited to, dedicated inkjet recording paper such as plain paper, high-quality paper, and glossy paper. Examples of the low-ink-absorbing recording medium 100 include printing paper such as art paper, coated paper, and matte paper. Although not limited to the following as the non-ink-absorbing recording medium 100, for example, on a substrate such as a plastic film that has not been subjected to a surface treatment for inkjet printing (that is, an ink-absorbing layer is not formed), and paper And those coated with plastic and those with a plastic film adhered thereto. The plastic is not particularly limited, and examples thereof include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

Next, the printing apparatus 1 will be described. As described above, the printing apparatus 1 includes the apparatus main body 2, the leg (stand) 3, the curing unit 4, and the control unit 8 (see FIGS. 1 to 3).
As shown in FIG. 1 and FIG. 2, the apparatus main body 2 includes a transport unit 21, a head unit (head assembly) 5, a heating member (heating unit) 7 </ b> A and a heating member (heating unit) 7 </ b> B, and a moving unit ( (Moving part) 22, platen 24, preheater 25, drying heater 26, blower fan 27, suction fan 28, and housing (housing) 29.

The casing 29 is a box that collectively stores the conveying means 21, the head unit 5, the heating members 7A and 7B, the moving means 22, the platen 24, the preheater 25, the drying heater 26, the blower fan 27, and the suction fan 28. Shaped member. Further, the outer shape of the housing 29 (device main body 2) is a long shape along the y-axis direction.
The transport unit 21 transports the recording medium 100 and includes rollers 211 and 212, a motor 213, and a motor drive circuit 214 that are arranged above and below. The roller 211 is a main driving roller connected to the motor 213 via a speed reduction mechanism (not shown) such as a gear, and the roller 212 is a driven roller.

The motor drive circuit 214 is electrically connected to the control unit 8. The motor drive circuit 214 drives the motor 213 based on a signal from the control unit 8.
The roller 211 can convey the recording medium 100 together with the roller 212, that is, send it out, by rotating by driving the motor 213 while sandwiching the recording medium 100 with the roller 212. Hereinafter, the direction in which the recording medium 100 is transported is referred to as “transport direction”.

The pre-heater 25 heats the recording medium 100 in advance before the recording medium 100 is printed. The preheater 25 includes a housing 252 having an abutting surface 251 with which the back surface of the recording medium 100 abuts, a heating element 253 housed in the housing 252, and a heating element driving circuit 254.
The contact surface 251 is configured by a curved surface curved in an arch shape. The recording medium 100 abuts against the abutting surface 251 while being conveyed by the conveying unit 21. At this time, heat from the heating element 253 is transmitted to the recording medium 100 via the contact surface 251. Thereby, the recording medium 100 can be heated. The surface temperature of the recording medium 100 when the preheater is heated is preferably, for example, +5 degrees or more with respect to the surface temperature of the recording medium 100 on the platen 24.

Moreover, it is preferable that the curvature of the contact surface 251 is gradually decreased toward the downstream side in the transport direction, that is, in the positive x-axis direction.
Moreover, it does not specifically limit as a constituent material of the housing 252, For example, aluminum, aluminum alloy, or stainless steel can be used.
The heating element 253 is made of a metal material having a relatively high electrical resistance, such as a nichrome wire. The heating element 253 is driven by the heating element driving circuit 254. The heating element driving circuit 254 is electrically connected to the control unit 8 and energizes the heating element 253 based on a signal from the control unit 8 to cause the heating element 253 to generate heat.

A platen 24 is disposed downstream of the preheater 25 in the transport direction. The platen 24 is composed of a plate member, and supports the recording medium 100 from below when ink is applied to the recording medium 100. The platen 24 can be made of the same material as that of the housing 252, for example.
As shown in FIG. 2, the platen 24 is formed with a large number of openings 242 that open to the upper surface 241 thereof. These openings 242 are arranged along the surface direction of the platen 24.

  A suction fan 28 is disposed below the platen 24. When the suction fan 28 is operated, that is, rotated, the recording medium 100 on the platen 24 can be sucked through the openings 242 of the platen 24. Thereby, the posture of the recording medium 100 at the time of ink application can be stabilized, so that the ink is reliably applied to a desired position of the recording medium 100.

The suction fan 28 is not particularly limited, and for example, various fans such as a multiblade fan (sirocco fan) can be used.
As shown in FIGS. 2 and 4B, the head unit 5 includes a droplet discharge head (discharge unit) 23 having a large number of nozzle openings 232 that open downward, and a carriage 6. .

The droplet discharge head 23 includes a piezoelectric element 231 serving as a drive source for discharging ink, and a piezoelectric element drive circuit 233 for driving the piezoelectric element 231.
The piezoelectric element 231 is composed of, for example, a piezoelectric body such as a piezoelectric element, and vibrates when a voltage is applied from the piezoelectric element driving circuit 233 to eject ink from the nozzle port 232.
The piezoelectric element drive circuit 233 is electrically connected to the control unit 8. The piezoelectric element driving circuit 233 drives the piezoelectric element based on a signal from the control unit 8.

The carriage 6 has a storage portion that stores the droplet discharge head 23. By storing the droplet discharge head 23 in the storage portion 61, the droplet discharge head 23 can be supported.
In addition, it does not specifically limit as a constituent material of the carriage 6, For example, various resin materials and various metal materials can be used.

  The moving means 22 reciprocates the head unit 5 with respect to the recording medium 100 in a direction orthogonal to (intersects with) the conveyance direction, that is, in the y-axis direction. The configuration of the moving means 22 is not particularly limited, and in this embodiment, the motor 221, a ball screw (not shown) connected to the motor 221, and a linear guide (not shown) arranged in parallel with the ball screw. And a motor drive circuit 222 for driving the motor 221. The motor drive circuit 222 is electrically connected to the control unit 8 and drives the motor 221 based on a signal from the control unit 8.

The recording medium 100 is ejected from the droplet ejection head 23 while the recording medium 100 is conveyed in the positive x-axis direction while the droplet ejection head 23 reciprocates by the operation of the moving means 22. The ink can be applied to the ink and printed.
As described above, in the printing apparatus 1, the operation of the droplet discharge head 23 by the moving unit 22 can be called “main operation”, and the operation of the recording medium 100 by the transport unit 21 can be called “sub operation”.

In the reciprocation of the droplet discharge head 23, a path toward the negative y-axis direction is referred to as an “outward path”, and a path toward the positive y-axis direction is referred to as a “return path”.
As shown in FIG. 4B, the heating member 7 </ b> A is provided on the y-axis positive side of the platen 24, and the heating member 7 </ b> B is provided on the y-axis negative side of the platen 24. Since the heating members 7A and 7B have the same configuration, the heating member 7A will be representatively described below.

The heating member 7 </ b> A includes a heating element 71 and a heating element driving circuit 72.
The heating element 71 is made of, for example, a metal material having a relatively high electrical resistance such as a nichrome wire. The heating element 71 generates heat when energized.
The heating element 71 is driven by a heating element driving circuit 72. The heating element drive circuit 72 is electrically connected to the control unit 8 and applies a voltage E to the heating element 71 based on a signal from the control unit 8 to cause the heating element 71 to generate heat.

The heating temperature of the heating member 7A is preferably about 30 to 90 ° C., more preferably about 50 to 70 ° C. when the environmental temperature is normal temperature (about 25 ° C.).
As shown in FIG. 2, the drying heater 26 is disposed to face the platen 24 via the head unit 5. The drying heater 26 irradiates infrared rays toward the ink while the ink is being applied on the recording medium 100 to promote drying of the ink.

The drying heater 26 includes a tube body 261 disposed along the y-axis direction, a heating element 262 disposed through the tube body 261, and a heating element drive circuit 263.
The tube 261 is made of a metal material, and particularly preferably made of iron. The total length of the tube body 261 along the y-axis direction is preferably sufficiently longer than the width of the recording medium 100 along the y-axis direction. Thereby, it is possible to reliably irradiate infrared rays toward the entire ink on the recording medium 100 passing under the tube body 261 (drying heater 26).

  The heating element 262 generates heat when energized, and is configured by a heating wire such as a nichrome wire, for example. And when the heat generating body 262 generates heat, the tube body 261 is heated and irradiated with infrared rays. Thereby, the water | moisture content in an ink can be evaporated reliably, and, therefore, an ink can be dried. The heating temperature when the tube body 261 is heated is preferably, for example, not less than 400 degrees and not more than 800 degrees, and more preferably not more than 700 degrees.

  The ink on the recording medium 100 may be dried from the back side of the recording medium 100, that is, the platen 24 may function as a heating plate. In this case, due to the nature of the ink, There is a possibility that a film is formed in the ink, and the evaporation of moisture in the ink is hindered by this film. Therefore, a structure in which the ink is dried from the surface side of the recording medium 100 as in the present embodiment is preferable.

  The blower fan 27 is disposed on the upstream side in the transport direction in the upper part of the apparatus main body 2. The blower fan 27 sends out the air 271 along the transport direction. With this wind 271, water vapor generated by heating the ink can be pushed out of the apparatus main body 2. Thereby, for example, it is possible to prevent dew condensation on the droplet discharge head 23.

As the blower fan 27, various fans such as a multi-blade fan can be used as in the suction fan 28, for example.
As shown in FIG. 1, the apparatus main body 2 is supported by the leg part 3 from the lower side (refer FIG. 1). The leg portion 3 includes a frame portion 31, four casters 32, and two adjuster feet (fixing tools) 33.
The frame portion 31 is an assembly that is assembled by appropriately connecting and fixing a plurality of rod-shaped members 311.
Each caster 32 is disposed and fixed at a lower portion of the frame portion 31 so as to be separated from each other. Thereby, the printing apparatus 1 can be conveyed.

  Each adjuster foot 33 is also fixed to the lower portion of the frame portion 31. Each adjuster foot 33 is disposed in the vicinity of two casters 32 located on the negative side of the x-axis among the four casters 32. After the printing apparatus 1 is transported, when the movement of the printing apparatus 1 is restricted, that is, when it is fixed, each adjuster foot 33 can be brought into contact with the floor surface to regulate the movement.

The curing unit 4 is disposed on the downstream side in the transport direction with respect to the apparatus main body 2. As shown in FIG. 2, the curing unit 4 includes a curing heater 41, a cooling fan 42, and a housing (housing) 43.
The housing 43 is a box-shaped member that collectively stores the curing heater 41 and the cooling fan 42. Further, the outer shape of the housing 43 (curing unit 4) is a long shape along the y-axis direction, and the length thereof is shorter than that of the housing 29 (device main body 2).

The housing 43 is provided with a passage 432 through which the recording medium 100 passes. The end point of 432 is a discharge port 433 through which the recording medium 100 is discharged.
In the middle of the passage 432, the curing heater 41 is disposed on the side of the recording medium 100 that passes through the passage 432, that is, on the front side of the recording medium 100. The curing heater 41 irradiates infrared rays toward the ink on the recording medium 100 to heat and cure the ink. By this curing, the ink is reliably fixed on the recording medium 100.

As shown in FIG. 2, the curing heater 41 includes a tube body 411 disposed along the y-axis direction, and a heating element 412 inserted into the tube body 411.
The tube body 411 is made of a metal material, and particularly preferably made of iron. The total length of the tube body 411 along the y-axis direction is preferably sufficiently longer than the width of the recording medium 100 along the y-axis direction. Thereby, it is possible to reliably irradiate infrared rays toward the entire ink on the recording medium 100 passing under the tube body 411 (curing heater 41).

  The heating element 412 generates heat when energized, and is composed of a heating wire such as a nichrome wire, for example. And when the heat generating body 412 generates heat, the tubular body 411 is heated and irradiated with infrared rays. As a result, the resin component in the ink is cured. As a result, the recording medium 100 that is a printed product, that is, the ink is cured, has excellent weather resistance and abrasion resistance.

Note that the surface temperature of the recording medium 100 at the time of heating is preferably, for example, 60 degrees to 120 degrees, and more preferably 80 degrees to 100 degrees.
The surface temperature of the recording medium 100 can be detected by using, for example, an infrared sensor (IR sensor). Further, setting the surface temperature of the recording medium 100 to be in the numerical range can be performed by appropriately switching ON / OFF of the curing heater 41 based on the detection result of the infrared sensor.

A cooling fan 42 is arranged downstream of the curing heater 41 in the transport direction. The cooling fan 42 sends air toward the recording medium 100 heated by the curing heater 41 to cool the recording medium 100.
As the cooling fan 42, various fans such as a multi-blade fan can be used as in the case of the blower fan 27 and the suction fan 28.

In the present embodiment, each part constituting the curing unit 4 is controlled independently from the apparatus main body 2. That is, the control unit 8 is controlled by another control unit (not shown).
As shown in FIG. 3, the control unit 8 includes a CPU (Central Processing Unit) 81 that performs various controls, and a storage unit 82.
The CPU 81 is electrically connected to the motor driving circuit 214, the motor driving circuit 222, each heating element driving circuit 72, the heating element driving circuit 254, the heating element driving circuit 263, and the piezoelectric element driving circuit 233.

  The storage unit 82 includes a storage medium in which various information, data, tables, arithmetic expressions, programs, and the like are stored. This storage medium is, for example, a volatile memory such as a RAM or a nonvolatile memory such as a ROM. EPROMs, EEPROMs, flash memories, and the like, which are rewritable (erasable and rewritable) nonvolatile memories, etc., and various semiconductor memories, IC memories, and the like.

Now, as shown in FIG. 5B, during printing, the droplet discharge head is deprived of heat to the platen side, so that the temperature T will continue to decrease over time. in the present invention, as shown in FIG. 5 (a), it is possible to keep the droplet discharge head 23 to a suitable temperature (temperature between the lower limit value T ₁ and the upper limit value T _2). In the former case, the viscosity of the ink is increased, and depending on the degree, the nozzle may be clogged or the printing accuracy may be reduced.

An area where ink is applied to the recording medium 100 is referred to as a “print area 200” (see FIG. 4B). In the present embodiment, the printing area 200 is the entire width direction (y-axis direction) of the platen 24 when viewed from the transport direction.
Of the areas outside the print area 200, the area on the y axis positive side with respect to the print area 200 is defined as the outer area 500, and the area on the y axis negative side with respect to the print area 200 is defined as the outer area 600. A region of the outer region 500 where the heating member 7A is provided is referred to as a heating region 300, and a region of the outer region 600 where the heating member 7B is provided is referred to as a heating region 400.

As shown in FIG. 4B, in the present embodiment, for ease of understanding, as an example, the droplet discharge head 23 includes a heating area 300 and a print area regardless of the size of the print pattern in the print area 200. The entire region 200 and the heating region 400 are moved. In the forward path, the droplet discharge head 23 moves in the order of the heating area 300, the printing area 200, and the heating area 400. In the return path, the droplet discharge head 23 moves in the order of the heating region 400, the printing region 200, and the heating region 300.
Here, as described above, the heating member 300 is provided in the heating region 300, and the heating member 7 </ b> B is provided in the heating region 400.

Therefore, in the forward path, first, when passing through the heating region 300, the heat Q from the heating member 7A is transmitted to the droplet discharge head 23, and the droplet discharge head 23 is heated. When passing through the printing region 200, the droplet discharge head 23 dissipates heat toward the platen 24, so that the temperature slightly decreases. However, the droplet discharge head 23, before the temperature T is below the lower limit T _1, and enters the heating zone 400, and heat Q is transferred from the heating member 7B, is heated immediately again. On the other hand, in the return path, the droplet discharge head 23 is heated by the heating member 7B in the same manner as described above when passing through the heating region 400. And when passing the printing area | region 200, temperature falls a little. However, the droplet discharge head 23 which passes through the print area 200 enters the heated area 300 before the temperature T is below the lower limit T _1, immediately heated again by the heating member 7A.

As described above, in the printing apparatus 1, in the printing region 200, the temperature T of the droplet discharge head 23 once decreases slightly, but before the temperature T falls below the lower limit value T ₁ , The droplet discharge head 23 can be heated immediately. As a result, the temperature T of the droplet discharge head 23 can be kept as constant as possible within an appropriate temperature range (see the solid line in FIG. 5). Therefore, the viscosity of the ink can be kept as constant as possible. For this reason, it is possible to prevent clogging of nozzles and a decrease in printing accuracy. As a result, the droplet discharge head 23 can stably discharge ink.

The lower limit _{T 1} and the upper limit value _{T 2} are preferably in the range of about 30 to 60 ° C., and more preferably about 40 to 50 ° C..
In the printing apparatus 1, heating members 7 </ b> A and 7 </ b> B are provided on both sides in the moving direction of the droplet discharge head 23 via the printing region 200. As a result, the droplet discharge head 23 can be heated regardless of whether it moves to the positive side or the negative side of the y-axis.

In the forward path, the droplet discharge head 23 performs an accelerating motion in the heating region 300, performs a uniform motion at a speed V ₀ in the printing region 200, and performs a decelerating motion in the heating region 400. In the return path, the droplet discharge head 23 performs an acceleration motion in the heating region 400, performs a uniform motion in the printing region 200, and performs a deceleration motion in the heating region 300. Thus, as shown to Fig.4 (a), the heating area | region 300,400 is an acceleration / deceleration area | region which performs an acceleration movement or a deceleration movement. That is, each of the heating regions 300 and 400 also serves as an acceleration / deceleration region. Thereby, the moving distance of the droplet discharge head 23 can be shortened compared with the case where an acceleration / deceleration region is provided separately from the heating regions 300 and 400. Therefore, the printing apparatus 1 can be downsized.

  Furthermore, since the moving distance of the droplet discharge head 23 can be shortened, the time required for one reciprocation can be relatively shortened. Thereby, the timing which passes the printing area | region 200, ie, the period which applies an ink in the printing area | region 200, can be made comparatively short. Therefore, the time until printing is completed can be shortened. Therefore, the processing speed of the printing apparatus 1 can be increased.

Second Embodiment
FIG. 6 is a block diagram showing a second embodiment of the printing apparatus of the present invention, and FIG. 7 is a flowchart showing the operation of the control unit during printing.
Hereinafter, the second embodiment of the printing apparatus of the present invention will be described with reference to this figure, but the description will focus on differences from the above-described embodiment, and the description of the same matters will be omitted.

This embodiment is the same as the first embodiment except that the control of the control unit is mainly different.
As illustrated in FIG. 6, the printing apparatus 1 includes a temperature detection unit 51 that detects the temperature T of the droplet discharge head 23. The temperature detection unit 51 is electrically connected to the control unit 8 and transmits a signal including the detection result of the temperature T of the droplet discharge head 23 to the control unit 8 during printing. This temperature detection part 51 can be comprised with a thermocouple, a thermistor, an infrared sensor etc., for example.

By the way, when printing is performed for a relatively long time, the droplet discharge head 23 may be excessively heated by the heating members 7A and 7B. However, lowering the temperature T of the droplet discharge head 23, when a value above the upper limit T ₂ that has been set is to reduce the voltage E to be applied to each heating element 71, heating element 7A, the heating temperature of 7B Let This can reliably prevent the droplet discharge head 23 from being excessively heated by the heating members 7A and 7B.
Moreover, if, temperature increase T of the droplet discharge head 23, when the lower limit value T ₁ that is set is to increase the voltage E to be applied to each heating element 71, heating element 7A, the heating temperature of 7B Let This enables the temperature T of the droplet discharge head 23 is prevented from falling below the lower limit T _1.

Hereinafter, this control program will be described based on the flowchart shown in FIG.
The temperature detection unit 51 detects the temperature of the droplet discharge head 23 (step S101).
Then, the temperature T detected in step S101 it is determined whether or not lower than the upper limit value _{T 2} (step S102). Temperature T detected in step S102 is when determining that falls below the upper limit value T ₂ are, determines whether or not the temperature T is above the lower limit value T ₁ (step S104).

Here, in step S102, when the temperature T is determined to be greater than than the upper limit value T ₂ are, the heating member 7A, reduce the voltage E applied to 7B, than the upper limit value T ₂ the temperature T Lowered (step S103). Then, the temperature T is determined whether exceeds than the lower limit value T ₁ in step S104.
If the temperature T is determined to be greater than the lower limit value T ₁ in step S104, it is determined whether or not printing is completed (step S106). If it is determined in step S106 that printing has been completed, the driving of each unit of the printing apparatus 1 is stopped.

In step S104, when the temperature T is determined to be lower than the limit value T1, the heating member 7A, to increase the voltage E applied to 7B, higher than the lower limit value T ₁ and temperature T. Then, the process returns to step S102 again, and the above control is repeated until it is determined in step S106 that printing has been completed.
According to such a second embodiment, the temperature T after heating the droplet discharge head 23 can be reliably heated to an appropriate temperature. That is, the temperature T of the droplet discharge head 23, certainly higher than the lower limit value T _1, it can be made lower than the upper limit value T _2.

<Third Embodiment>
FIG. 8 is a schematic front view showing a third embodiment of the printing apparatus of the present invention, where (a) is a diagram showing a state in which the ejection unit is reciprocating in the printing region, and (b) is an ejection. It is a figure which shows the state which the part moved to the heating area | region.
Hereinafter, the third embodiment of the printing apparatus of the present invention will be described with reference to this drawing, but the description will focus on differences from the above-described embodiment, and the description of the same matters will be omitted.
The present embodiment is the same as the second embodiment except that the operation of the control unit is different.

As shown in FIG. 8 (a), in this embodiment, the droplet discharge head 23 is different from the second embodiment, to a temperature T of the temperature detecting unit 51 has detected is less than the lower limit T ₁ is printed Printing can continue in region 200. Then, as shown in FIG. 8 (b), when the detected temperature T is below the lower limit T _1, to move the droplet discharge head 23 in the heating region 400. Thereby, the heat Q of the heating member 7B is transmitted to the droplet discharge head 23, and the temperature T rises. The staying time of the heating region 400 of the droplet discharge head 23 is, for example, until the temperature T reaches the median value T ₀ between the temperature T ₁ and the temperature T ₂ . When the temperature T reaches the median value T ₀ , the droplet discharge head 23 is moved again to the printing region 200 and printing is resumed.

In the case where the temperature T of the droplet discharge head 23 is below the lower limit value T _1, it may be moved to the opposite side of the heating region 300 of the heating unit 400.
According to the third embodiment, in order to move in only the heating region 300 or heating region 400 when the temperature T of the droplet discharge head 23 is below the lower limit value T _1, without waste liquid droplet ejection head 23 heated can do. In addition, since the residence time of the printing area 200 can be increased as much as possible, printing on the recording medium 100 can be performed quickly.

  Further, which of the heating regions 300 and 400 is moved may be determined according to the position of the droplet discharge head 23. For example, when the droplet discharge head 23 is located on the y-axis positive side of the print region 200 with respect to the center P in the y-axis direction of the print region 200, the droplet discharge head 23 is moved to the heating region 300. On the other hand, when the droplet discharge head 23 is located on the y-axis negative side from the center P, it is moved to the heating region 400. Thereby, the moving distance to the heating region can be shortened as much as possible, and heating of the droplet discharge head 23 can be started quickly.

<Fourth embodiment>
FIG. 9 is a graph showing the relationship between the voltage E applied to the heating element of the heating unit and the moving speed V of the ejection unit in the fourth embodiment of the printing apparatus of the present invention.
Hereinafter, the fourth embodiment of the printing apparatus of the present invention will be described with reference to this drawing. However, the difference from the above-described embodiment will be mainly described, and description of similar matters will be omitted.

This embodiment is the same as the first embodiment except that the operation of the control unit is different.
In the printing apparatus 1, as the moving speed (average speed) V when passing through the heating regions 300 and 400 of the droplet discharge head 23 increases, the passage time of the droplet discharge head 23 in the heating regions 300 and 400 decreases. Insufficient heating. For this reason, as the moving speed V increases, the voltage E applied to the heating elements 71 of the heating members 7A and 7B is increased to increase the heating temperature of the heating members 7A and 7B.

On the other hand, as the moving speed V when passing through the heating regions 300 and 400 of the droplet discharge head 23 becomes slower, the residence time in the heating regions 300 and 400 of the droplet discharge head 23 becomes longer and the heating becomes excessive. For this reason, as the moving speed V becomes slower, the voltage E is reduced to lower the heating temperature of the heating members 7A and 7B.
In the present embodiment, a calibration curve K ₁ for obtaining a value of the voltage E such that the temperature T is higher than the temperature T _{1 and} lower than the temperature T ₂ from the moving speed V is previously stored in the storage unit 82. It is stored (see FIG. 9). For example, when the moving speed V is the speed V ₁ , the temperature T is higher than the temperature T _{1 and} lower than the temperature T _{2 at} the voltage E ₁ .

The calibration curve K _1, for example, is stored wherein the storage unit 82 as the (arithmetic expression) or table. Control unit 8, on the basis of a calibration curve K _1, determines the voltage E in accordance with the moving velocity V of the droplet discharge head 23. Accordingly, the heating members 7A and 7B can heat the droplet discharge head 23 at an appropriate heating temperature regardless of the magnitude of the moving speed V of the droplet discharge head 23.
According to the fourth embodiment, the same effect as that of the first embodiment can be obtained.

<Fifth Embodiment>
FIG. 10 is a graph showing the relationship between the voltage E applied to the heating element of the heating unit and the separation distance G between the discharge unit and the heating unit in the fifth embodiment of the printing apparatus of the present invention.
Hereinafter, the fifth embodiment of the printing apparatus of the present invention will be described with reference to this drawing. However, the description will focus on differences from the above-described embodiment, and description of similar matters will be omitted.
This embodiment is the same as the fourth embodiment except that the operation of the control unit is different.

  In the printing apparatus 1, as the distance G between the heating members 7A and 7B passing through the heating regions 300 and 400 of the droplet discharge head 23 and the droplet discharge head 23 increases, the liquid from the heating members 7A and 7B increases. The heat Q is hardly transmitted to the droplet discharge head 23. For this reason, as the separation distance G increases, the voltage E applied to the heating elements 71 of the heating members 7A and 7B is increased to increase the heating temperature of the heating members 7A and 7B.

On the other hand, as the distance G decreases, the heat Q is more easily transferred from the heating members 7A and 7B to the droplet discharge head 23. For this reason, as the separation distance G is decreased, the voltage E is decreased and the heating temperature of the heating members 7A and 7B is decreased.
Therefore, in the present embodiment, a calibration curve K ₂ for obtaining a voltage E at which the temperature T is higher than the temperature T _{1 and} lower than the temperature T ₂ from the separation distance G is stored in the storage unit 82 in advance. It is stored (see FIG. 10). For example, when the distance G is the distance G _1, greater than temperature T ₁ of the temperature T is at the voltage E _1, it is smaller than than the temperature T _2.

The calibration curve K _2, for example, is stored wherein the storage unit 82 as the (arithmetic expression) or table. The control unit 8 determines the voltage E according to the separation distance G based on the calibration curve K2. Accordingly, the heating members 7A and 7B can heat the droplet discharge head 23 at an appropriate heating temperature regardless of the size of the separation distance G.
According to the fifth embodiment, the same effect as that of the fourth embodiment can be obtained.

<Sixth Embodiment>
FIG. 11 is a graph showing the relationship between the voltage E applied to the heating element of the heating unit and the number N of ejections that the ejection unit ejects ink in the sixth embodiment of the printing apparatus of the present invention.
Hereinafter, the sixth embodiment of the printing apparatus of the present invention will be described with reference to this drawing. However, the difference from the above-described embodiment will be mainly described, and the description of the same matters will be omitted.
This embodiment is the same as the fourth embodiment except that the operation of the control unit is different.

In the printing apparatus 1, when the droplet discharge head 23 discharges ink, a voltage is applied to the internal piezoelectric element 231, the piezoelectric element 231 generates heat, and the temperature of the droplet discharge head 23 slightly increases. Accordingly, the heating temperature of the heating members 7A and 7B is lowered when the number of ejections N at which the droplet ejection head 23 ejects ink is relatively high, and the heating temperature of the heating members 7A and 7B is lowered when the number of ejections N is relatively small. To increase.
In the printing apparatus 1, a calibration curve K ₃ for obtaining a voltage E value such that the temperature T is higher than the temperature T _{1 and} lower than the temperature T ₂ from the number of ejections N is stored in the storage unit 82 in advance. (See FIG. 11). For example, when the ejection number N is the number N ₁ , the temperature T is higher than the temperature T _{1 and} lower than the temperature T _{2 at} the voltage E ₁ .

The calibration curve K _3, for example, is stored wherein the storage unit 82 as the (arithmetic expression) or table. Control unit 8, on the basis of a calibration curve K _3, determines the voltage E in accordance with the ejection number N of ink. Accordingly, the heating members 7A and 7B can heat the droplet discharge head 23 at an appropriate heating temperature corresponding to the number of ink discharges of the droplet discharge head 23.
According to the fifth embodiment, the same effect as that of the first embodiment can be obtained.

As mentioned above, although the printing apparatus and printing method of this invention were demonstrated about embodiment of illustration, this invention is not limited to this, Each part which comprises a printing apparatus is arbitrary which can exhibit the same function. It can be replaced with that of the configuration. Moreover, arbitrary components may be added.
In addition, the printing apparatus and the printing method of the present invention may be a combination of any two or more configurations (features) of the above embodiments.

In each of the above embodiments, the effect of the present invention can be achieved even if one of the pair of heating members is omitted.
In each of the above embodiments, the platen and the heating member are configured as separate bodies. However, the present invention is not limited to this, and the heating member may be incorporated in the platen. In this case, the heating area is set at a position outside the printing area on the platen.

Moreover, in each said embodiment, although each heating member is spaced apart and provided with the platen, it is not limited to this in this invention, You may contact with a platen.
In the above-described embodiment, the printing apparatus and the printing method using “latex ink” as the ink used for printing are described. However, the present invention is not limited to this, and a configuration using an ultraviolet curable ink that is cured by a UV lamp. The same effect can be obtained even with a configuration using water-based ink.

DESCRIPTION OF SYMBOLS 1 ... Printing apparatus 2 ... Apparatus main body 21 ... Conveyance means 211 ... Roller 212 ... Roller 213 ... Motor 214 ... Motor drive circuit 22 ... Moving means 221 ... Motor 222 ... Motor drive circuit 23 ... Droplet discharge head 231 ... Piezoelectric element 232 ... Nozzle port 233 ... Piezoelectric element drive circuit 24 ... Platen 241 ... Upper surface 242 ... Opening 25 ... Preheater 251 ... Abutment surface 252 ... Housing 253 ... Heating element 254 ... Heating element drive circuit 26 ... Drying heater 261 ... Tube 262 ... Heating element 263 ... Heating element drive circuit 27 ... Blower fan 271 ... Wind 28 ... Suction fan 29 ... Housing 3 ... Leg part 31 ... Frame part 32 ... Caster 33 ... Adjuster foot 4 ... Curing unit 41 ... Curing heater 411 ... Tubing 412 ... Heating element 42 ... Cooling fan 43 ... Housing 432 ... Passage 433 ... Discharge port 5 ... Head unit 51 ... Temperature detection part 6 ... Carriage 61 ... Storage part 62 ... Bottom plate 63 ... Front plate 64 ... Rear plate 65 ... Side plate 66 ... Side plate 7A ... Heating member 7B ... Heating member 71 ... Heating element 72 ... Heating element drive circuit 8 ... Control unit 81 ... CPU 82 ... Storage unit 100 ... Recording medium 200 ... Printing area 300 ... Heating area 301 ... Area 311 ... Member 400 ... Heating area 401 ... Area 500 ... Outer area 600 ... Outer region 621 ... opening V ... moving speed E ... voltage G ... separation distance K ₁ ... calibration curve K ₂ ... calibration curve K ₃ ... calibration curve N ... number of discharges Q ... heat S ... gap T ... temperature T ₁ ... lower limit T ₂ ... Upper limit

Claims (10)

An ejection unit that ejects ink onto a recording medium;
A moving part for reciprocating the discharge part;
A heating unit provided in an outer region outside a printing region that ejects the ink while the ejection unit is moved by the operation of the moving unit;
A controller that controls the discharge unit, the moving unit, and the heating unit;
The said control part controls the said heating part so that the said outer side area | region becomes high temperature rather than the said printing area | region, The printing apparatus characterized by the above-mentioned. A part of the outer region is an acceleration / deceleration region in which the discharge unit accelerates or decelerates,
The printing apparatus according to claim 1, wherein the heating unit is provided in the acceleration / deceleration region.   The printing apparatus according to claim 1, further comprising a temperature detection unit that detects a temperature of the discharge unit.   The control unit controls the moving unit so that the discharge unit reciprocates in the print region, and when the temperature of the discharge unit detected by the temperature detection unit falls below a threshold value, the control unit controls the discharge unit. The printing apparatus according to claim 3, wherein the printing unit is moved to the outer region to heat the ejection unit.   The control unit controls the moving unit so that the discharge unit passes through the print region and the outer region in both the forward path and the return path, and the temperature of the discharge unit detected by the temperature detection unit exceeds a threshold value. The printing apparatus according to claim 3, wherein the temperature of the heating unit is lowered when the temperature is increased.   The printing apparatus according to claim 1, wherein the control unit adjusts a temperature of the heating unit according to a moving speed of the discharge unit in the outer region.   The said control part adjusts the temperature of the said heating part according to the separation distance of the said heating part and the said discharge part when the said discharge part passes on the said heating part, The any one of Claim 1 thru | or 6 The printing apparatus as described in. The discharge unit has a discharge number detection unit that detects the number of discharges for discharging the ink,
The printing apparatus according to claim 1, wherein the control unit adjusts a temperature of the heating unit based on the number of ejections detected by the ejection number detection unit.   The printing apparatus according to claim 1, wherein a pair of the heating units are provided via the printing region. An ejection unit that ejects ink onto a recording medium;
A moving part for reciprocating the discharge part;
A printing apparatus comprising a heating unit provided in an outer region outside a printing region that ejects the ink while the ejection unit is moved by the operation of the moving unit, and printing on the recording medium,
A printing method, wherein the outer region is at a higher temperature than the printing region.

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