JP2003182089A - Inkjet recorder and method of recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder and a method of recording wherein wiping can be surely performed without leaving a portion which is not wiped and ejection is highly stabilized. <P>SOLUTION: This inkjet recorder comprises a mechanism for wiping a nozzle face of a recording head by using a blade. This blade is made of silicone having a hardness in the range of 40-60 degree regulated by JIS-K-6301 and a speed for wiping the nozzle face is in the range of 20-80 mm/sec. An overlapped portion between the nozzle face and the blade is in the range of 1.0-2.0 mm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording apparatus and a recording method which have excellent cleaning properties and high ejection stability.

[0002]

2. Description of the Related Art An ink jet recording apparatus is used as a means for obtaining a high quality output image at a relatively low cost with a relatively simple apparatus. In recent years, inkjet recording apparatuses are required to have higher image quality and higher speed, and the recording density and the printing speed are increasing. Smaller droplets are indispensable for higher image quality, and the nozzle diameter tends to be smaller with smaller droplets. On the other hand, in the case of ink, when ink droplets land on a recording medium, the image density increases as the dots spread evenly, and it is possible to reduce failures called banding, so the surface tension of the ink tends to be low. .
The nozzle surface is usually water repellent (ink repellent) treated,
The ink repellency changes even if only a small amount of adhered matter is attached, and the emission stability decreases. In addition, the surface tension of the ink may be set low so that the ink droplets spread uniformly on the recording medium. However, the lower the surface tension of the ink, the easier the nozzle surface gets wet and the ejection stability deteriorates. Become. In order to prevent such a situation, the inkjet printer is usually provided with a maintenance mechanism. For example, sacking for removing the clogging inside the nozzle by depressurizing the nozzle from the outside and wiping for wiping off the adhered matter on the nozzle surface with a blade are typical. However, when an ink having a low surface tension is used, particularly when an ink having an insoluble coloring material is used, depending on the blade used for wiping, there is a tendency for wiping residue to occur, and ejection is likely to be unstable.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ink jet recording apparatus and a recording method which are free from unwiping during wiping and have high ejection stability.

[0004]

The above object of the present invention can be achieved by the following means.

1. In an inkjet recording apparatus having a mechanism for wiping the nozzle surface of a recording head using a blade, the blade is a silicone blade having a hardness of 40 degrees or more and 60 degrees or less defined by JIS-K-6301, and the blade is a nozzle. An ink jet recording apparatus, wherein a surface wiping speed is 20 to 80 mm / sec, and an overlap between the nozzle surface and the blade is 1.0 mm or more and 2.0 mm or less.

2. 2. The ink jet recording apparatus according to the above 1, wherein an ink having a surface tension of 30 to 35 mN / m is used.

3. 3. The ink jet recording apparatus according to 1 or 2 above, wherein an ink containing an insoluble coloring material is used.

4. A recording method using the ink jet recording apparatus according to any one of 1 to 3 above.

Wiping of the recording head in the ink jet recording apparatus means that the blade is relatively scanned with respect to the nozzle surface to wipe off ink droplets remaining on the nozzle surface. The scanning may be performed, or the blade may be scanned while the recording head is fixed.
Alternatively, both may be scanned together.

A blade made of silicone rubber is characterized by a high contact angle with ink, ink repellency, and good cleaning property, but has a drawback of rapid deterioration. The present invention improves the durability of the blade by setting the hardness of the blade made of silicone rubber to an appropriate hardness, and by adjusting the speed of the pressing and wiping of the blade against the nozzle surface to an appropriate range to improve the cleaning performance. He found that he could maintain sex. The hardness defined by JIS-K-6301 of the silicone rubber blade used in the present invention is 40 degrees or more 6
It is 0 degrees or less. Further, in order to moderately press the blade, the overlap between the nozzle surface and the blade is set in the range of 1.0 mm to 2.0 mm, and the wiping speed of the blade is set to 20 to 8 mm.
By setting the range to 0 mm / sec, it is possible to prevent unwiping residue, prevent deterioration of the blade, and maintain the cleaning performance for a long period of time.

In the present invention, the blade ink contact angle (using a receding contact angle described later) is preferably 60 ° or more.

In the present invention, when the hardness of the silicone rubber blade is less than 40 degrees (the hardness defined by JIS-K-6301), sufficient pressing cannot be obtained and wiping failure occurs, so that the nozzle surface is not covered. If the ink remains and the ejection stability deteriorates, and if it is 60 degrees or more, the initial cleaning property is good, but the pressure becomes too high, and the cleaning property deteriorates as the blade deteriorates and the nozzle surface is damaged. The silicone rubber hardness within the above range is good. Further, if the hardness is too high, the ink is likely to be scattered by the repulsion of the blade. Therefore, it is convenient to use the silicone blade in this range.

The pressure applied when the blade sweeps the nozzle surface is represented by the amount of overlap between the blade and the nozzle surface. 1 and 2 are diagrams showing the amount of overlap between the blade and the nozzle surface. 1A shows a state in which the blade 17 sweeps the nozzle surface 5 to perform wiping (the arrow indicates the sweep direction), and the overlap amount is shown in FIG. 1B. It is defined by the overlap d between the nozzle surface 5 and the blade when the blade is brought to the position. In the present invention, the overlapping amount d is 1.0
It is not less than mm and not more than 2.0 mm. When the blade is inclined with respect to the nozzle surface and swept to perform wiping, the overlapping amount d can be similarly defined in FIGS. 2A and 2B.

If the amount of overlap is large, that is, if it is 2.0 mm or more, the pressing force of the blade against the nozzle surface becomes too strong, and the silicone rubber or the nozzle surface is damaged, resulting in poor wiping and deterioration of ejection stability. The cleaning performance is not so improved by using a low hardness (soft) blade. On the other hand, if the overlapping amount is too small (1.0 mm or less), the pressing force is too weak, resulting in poor wiping and deterioration of ejection stability.

The wiping speed is also 20 to 80 mm /, although it is related to the pressing of the blade against the nozzle surface.
If sec is appropriate, and if it is slower than this, cleaning will take time and maintenance will take time.
On the other hand, if it is faster than 80 mm / sec, the wiping failure becomes poor and the deterioration of the silicone rubber is accelerated to deteriorate the ejection stability. In addition, the nozzle surface is easily scratched due to deterioration of the silicone rubber.

By such wiping, good cleaning can be performed even for ink having a relatively small surface tension, that is, in the range of 30 to 35 mN / m.

The silicone rubber used as a blade material is obtained by mixing organopolysiloxane having a high degree of polymerization with a curing agent (for example, benzoyl peroxide), kneading the mixture and molding and vulcanizing it. The main component is dimethylpolysiloxane. is there. Those having the appropriate elasticity (hardness) and the appropriate water repellency are preferable. As a silicone rubber material,
For example, a material such as IS-825 50HS of Irumagawa Rubber Co., Ltd. is commercially available, and in the present invention, these are processed into a blade for wiping. Silicone rubber has appropriate ink repellency and has excellent properties as a blade material for cleaning a recording head of an inkjet printer using an aqueous ink.

The nozzle surface of the recording head is preferably water-repellent (ink-repellent). For example, a material forming the nozzle surface, for example, a plastic such as polyester or polyamide, a material such as glass, a ceramic or a metal can be repelled. An aqueous coating is used.

The method for applying a water-repellent and ink-repellent coating to the nozzle surface is described in, for example, Japanese Patent Publication No. 52-248
21 and JP-A-56-2862 disclose coatings of materials such as polytetrafluoroethylene (PTFE) having a property of repelling ink such as fluorine resin and silicone resin, JP-A-57-72866 and 60-255441.
The use of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) as the ink repellent film is described in each of the publications. This FEP has a low surface energy (ink repellency) equivalent to that of polytetrafluoroethylene (PTFE), but its viscosity at the time of heating and melting is lower than that of PTFE, and an aqueous dispersion is applied to make uniform by heating and melting. When forming a film, a uniform film can be obtained at a temperature lower than that of PTFE in a short time, and the film forming processability is excellent.
Further, in JP 2001-71509 A, a method of mixing and coating an FEP water dispersion liquid and a silica sol particle dispersion liquid, drying and baking at 300 to 400 ° C. is also disclosed in JP-A-10-505.
No. 870 and the like also describe methods using a fluorine-containing polysiloxane compound.

The contact angle is used to measure and evaluate the ink repellency of the nozzle surface and the ink repellency of the blade.

Generally, when external force does not act, the forces acting on the droplet are gravity and surface tension. When the droplet becomes small, the surface area becomes very large relative to the weight, so that the influence of surface tension becomes overwhelmingly larger than that of gravity. Therefore, the force that affects the movement of microdroplets is the surface tension (σ: mN / m)
Will only be. The angle that a stationary droplet makes with the solid surface is called the equilibrium contact angle θe, or simply the contact angle θ. When the droplet starts moving, the equilibrium contact angle θe disappears and the advancing contact angle θe θa and the receding contact angle θr appear. The magnitude of the surface tension acting on the droplet is σ cos θa in the direction of advancing the droplet and σ cos θr in the direction of impeding the movement of the droplet.

The advancing contact angle θa is the contact angle with respect to the surface that is not yet wet with the liquid, and the receding contact angle θr is
Since it is the contact angle for a liquid-wetted surface, it is always θa
> Θr is established. When an external force acts on the droplet to start moving and θa and θr appear, at that time, a force of σcosθr-σcosθa acts on the droplet in a direction that hinders the movement of the droplet, which causes the movement of the droplet. It becomes an obstacle.

Since both the advancing contact angle θa and the equilibrium contact angle θe are contact angles with respect to a surface that has not yet been wet with liquid,
In many systems, θa≈θe holds. Since θr is a contact angle with respect to a surface already wet with a liquid, it greatly changes when the ink component is adsorbed on the solid surface or the functional group on the solid surface is inverted due to the influence of the ink. A system in which the advancing contact angle θa is large and the receding contact angle θr is small is preferable in order to prevent the liquid from getting wet and spreading and becoming spherical and rolling.

<Measurement of advancing contact angle and receding contact angle> Co., Ltd.
Measurement is performed using a contact angle meter CA-X manufactured by Kyowa Interface Science. 5 μl of the ink drop to be measured is placed on the substrate from the syringe. Further, a small amount of ink is supplied from the syringe to spread the droplets a little and the advancing contact angle is measured. Immediately, a small amount of ink is sucked into a syringe, the droplet is retracted, and the receding contact angle is measured.

FIG. 3 is a schematic view showing an example of the main constitution of the ink jet recording apparatus 1. The inkjet recording apparatus ejects ink onto a recording paper to perform printing, and as a main configuration of a portion for performing the printing, as shown in FIG. 1, a conveying unit (illustrated in FIG. 1) for conveying the recording paper 2 to the front during printing. Omitted), a recording head (head) 3 that ejects ink onto the recording paper 2, a carriage 4 that stores the recording head 3 for each of a plurality of colors, and a suction cap 16 and a blade 17 that performs maintenance of the recording head 3. A maintenance unit 5, a guide rail 6 for guiding the carriage 4 along the horizontal direction (arrow A) at the time of printing or maintenance, and a home position 7 having a moisturizing cap 8 serving as a waiting place for the carriage 4. , And a control unit (not shown) that controls these units. C
Each of the inks sent from the ink cartridge and the ink cartridge C is temporarily stored in the sub-tank T, and then sent to the recording head through the supply valve V, the ink supply path P, and the recording head.

The recording paper conveying means conveys the recording paper 2 on the printing area 9 in time with the operation of the carriage 4 during printing, and when the printing is completed, the recording paper 2 is conveyed.
Is conveyed downward from the print area (arrow B).

At the home position 7, moisturizing caps 8 for moisturizing the nozzle surface of the recording head are provided in the same number as the recording heads 3, and when the carriage 4 is on standby,
The nozzle surface of the recording head 3 is covered and hermetically sealed.

FIG. 4 is a schematic view showing the structure of the recording head. The recording head 3 includes an ink ejection main body 11 for ejecting ink, and the ink ejection main body 11 on the head substrate 10.
A temperature sensor (temperature measuring means) 12, which measures the temperature in the vicinity,
A flexible cable is connected, and a flexible cable connecting portion 13 for inputting / outputting signals to / from the ink discharge portion main body portion 11 and the temperature sensor 12 is installed. The surface (nozzle surface) of the ink ejection main body 11 that faces the recording paper 2 is the ejection port 1 that ejects ink.
A plurality of nozzle plates 15 are provided along the center line, and the discharge ports 14 communicate with the ink nozzles (flow paths).

The temperature sensor 12 is the ink discharge main body 1
The air temperature near 1 or the temperature of the head substrate 10 is measured, and is electrically connected to the control unit through the flexible cable connection unit 13.

As shown in FIG. 3, the carriage 4 is provided with a plurality of recording heads 3 for each color (yellow, magenta, cyan, black).

The maintenance unit 5 covers the ejection port and sucks the ink from the ejection port 14 and a nozzle surface 15 after the suction cap 16 sucks the ink. A blade 17 for wiping off the remaining ink, and although not shown in FIG.
And a blade cleaner portion for cleaning the blade. A plurality of (two in the present embodiment) suction caps 16 are provided side by side, and it is possible to suck a plurality of recording heads 3 at once during maintenance.

FIG. 5 shows the suction cap 16 and the suction means 2.
FIG. 2 is a configuration diagram showing an outline of an ink suction unit including 0. The suction cap 16 is provided with a lip portion 19 that covers the periphery of the nozzle surface 15 of the recording head 3 and has elasticity to maintain hermeticity. ing. Further, on the back surface of the suction cap 16, the suction cap 16 and the nozzle surface 1 are provided.
A suction pump (suction means) 20 for suctioning the inside of the space formed by 5 and an atmosphere communication valve 21 are connected, and the suction pump 20 covers the nozzle surface 15 covered with a suction cap 16 and sealed, Suction through the suction cap 16. Then, the suction pump 20 discharges the discharge port 1
The ink sucked from No. 4 is discharged to the waste ink tank 22.

Further, when the suction cap 16 is separated from the nozzle surface after suction, the suction cap 16 is separated from one end side first, and gradually separated to the other end (FIG. 3 ( a), (b), (c)). The suction cap 16 is supported on the side surface by a substantially L-shaped support piece 18, and is arranged so as to be substantially opposed to the nozzle surface 15 of the recording head 3.

Although the suction pump 20 is illustrated as the suction means in the present embodiment, any suction pump may be used as long as it sucks ink from the ejection port 14, and examples thereof include a piston and a cylinder. To be

The support piece 18 is composed of a body portion 23 for supporting the suction cap 16 and an extending portion 24 extending at a right angle from the lower end of the body portion 23. The body portion 23 and the extending portion 24. The joint is rotatably supported at the joint. Then, the extending portion 24 has a substantially elliptical cam (moving means) 26.
Are in contact. By rotating the cam 26, the support piece 18 is rotated, and accordingly, the suction cap 16 is attached to and detached from the nozzle surface 15 of the recording head 3.

The cam drive shaft 27 of the cam 26 is connected to a cam drive unit such as a motor, and is rotated by the control of the cam drive unit, and the suction cap 16 is separated from the recording head 3 at a predetermined position. (Standby position; FIG. 5C) and a position (FIG. 5A) where the nozzle surface 15 is covered and hermetically sealed.

FIG. 6 is a schematic view showing the structure of a wiping unit including a blade and a blade cleaner according to the present invention. As will be described later, the blade portion 17 is arranged so as to be inclined with respect to the nozzle surface so as to be brought into contact with the blade cleaner portion 37 of the blade at the same time for cleaning, and is configured to be inclined and sweep the nozzle surface. However, the blade body 35 formed of an elastic body having a thickness of about 0.5 to 2 mm wipes off the ink remaining on the nozzle surface 15 after the suction of the ink by the suction cap 16, and supports the blade body 35, And a blade movable part 36 that moves up and down (arrow E).

The blade cleaner portion 37 is installed inside the maintenance unit 5, and the blade body 35
An ink absorber 38 that absorbs and wipes off the ink is provided, and an absorber holding portion 39 that holds the ink absorber 38.

When the maintenance is started, first, the recording head 3 is moved by the movement of the carriage 4 and the suction cap 1 is moved.
Move to 6.

The movement of the carriage 4 is performed by driving a carriage driving unit (not shown), and
When the carriage sensor detects that the carriage 4 has moved to the suction position, the carriage drive unit stops and the carriage stops.

When the carriage 4 is stopped at the suction position, the suction cap 16 is moved to the nozzle surface 15 of the recording head 3 by the cam driving portion (not shown), and the nozzle surface 15 of the recording head 3 is sealed, The discharge port 14 is covered.

In this state, the operation of the suction pump 20 is started and the ink is sucked from the ejection port 14. This suction is performed until a predetermined time has elapsed, and is repeated a predetermined number of times.

When the suction pump 20 is stopped, thereafter, the atmosphere communication valve 21 is opened so that the suction cap 16 and the nozzle surface 15 can be easily separated from each other, and then the suction cap 1
Move 6 to the standby position.

Further, when the suction cap 16 is stopped,
The atmosphere communication valve 21 is closed, and the carriage 4 is attached to the nozzle surface 15
The carriage drive unit moves the blade 17 up to the blade 17 for wiping.

When it is detected that the carriage 4 has moved to the wipe position, the carriage drive unit stops and the carriage stops.

When the carriage 4 stops at the wipe position,
The blade portion 17 starts moving. When the blade 17 stops at the wipe position, the carriage moves relative to the blade to initiate the wipe. By moving the carriage 4 at a constant speed, the blade sweeps the nozzle surface 15 of the recording head at a constant speed (adjusted by the overlap between the nozzle surface and the tip of the blade) and wipes the nozzle surface 15 at the nozzle surface. Clean the deposited ink drops. FIG. 2A shows how the blade cleans the nozzle surface.

Upon completion of the wipe, the blade cleaner 17 cleans the blade 17.

When the cleaning of the blade portion 17 is completed, the carriage 4 moves to the home position 7 which is the standby position and stops.

When maintenance is not performed, the blade portion 17 stands by below the position where the ink absorber 38 of the blade cleaner portion 37 wipes the blade, as shown in FIG. 6A. When the nozzle surface 15 needs to be wiped, the blade movable unit 36 moves upward, thereby moving the blade main body 35 upward. During this movement, the upper surface of the blade body and the ink absorber 38 come into contact with each other. That is, the blade body 3
The ink remaining in No. 5 is absorbed by the ink absorber 38 by this operation. With such a configuration, the blade main body 35 is cleaned every time maintenance is performed, and it is possible to prevent deterioration of the blade 35 due to residual ink.

Further, when the blade movable portion 36 rises and the upper end of the blade main body 35 reaches the nozzle surface passing position F, the carriage 4 operates, and the upper surface of the blade main body 35 and the nozzle surface of the recording head 3 are operated. The ink that comes into contact with and remains on the nozzle surface 15 is wiped off by the blade body 35.

In the present embodiment, the nozzle surface 15 is brought into contact with the upper surface of the blade body 35 by the nozzle surface 15.
Since the ink remaining on the upper portion is wiped off, the upper surface side of the blade main body 35 is wiped off when the blade main body 35 is cleaned.

By using a silicone rubber blade (having the above hardness) as the blade 17 under the above-mentioned overlapping condition with the nozzle surface and the above wiping speed (relative speed to the recording head), excellent ink cleaning property can be obtained. ,
Further, it is possible to obtain an ink jet recording apparatus having a good wiping unit which does not deteriorate the cleaning performance even when it is repeatedly used.

The ink jet recording apparatus according to the present invention is more effective for aqueous ink having a relatively low surface tension in the range of 30 to 35 mN / m.

In the present invention, the aqueous ink is, for example, an ink containing 10% by mass or more of water based on the total mass of the ink, and the colorant of the ink is a water-soluble dye such as an acid dye or a direct dye. Any reactive dye, disperse dye, pigment or the like may be used.

Among these, in the ink jet recording apparatus according to the present invention, an ink containing an insoluble coloring material is preferable. Ink containing an insoluble coloring material, such as a pigment, is difficult to re-dissolve when exposed to an aqueous liquid by suction, etc., so it is easy to stick firmly and damage the blade. Therefore, in the case of the inkjet recording apparatus using the cleaning method according to the present invention, the cleaning property is good, and the ink residue on the nozzle surface is small.

As the insoluble coloring material used in the ink containing the insoluble coloring material, organic pigments such as insoluble pigments and lake pigments and carbon black can be preferably used.

The insoluble pigment is not particularly limited, but for example, azo, azomethine, methine, diphenylmethane, triphenylmethane, quinacridone, anthraquinone, perylene, indigo, quinophthalone, isoindolinone, isoindoline, azine, oxazine. ,
Thiazine, dioxazine, thiazole, phthalocyanine, diketopyrrolopyrrole and the like are preferable.

Specific pigments that can be preferably used include the following pigments. Examples of magenta or red pigments include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15,
C. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1,
C. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123,
C. I. Pigment Red 139, C.I. I. Pigment Red 144, C.I. I. Pigment Red 149, C.I.
I. Pigment Red 166, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I.
Pigment Red 222 and the like.

Examples of pigments for orange or yellow include C.I. I. Pigment Orange 31, C.I.
I. Pigment Orange 43, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I.
Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 9
4, C.I. I. Pigment Yellow 138 and the like.

As the pigment for green or cyan,
For example, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 1
5: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

A pigment dispersant may be used in these pigments if necessary, and examples of the pigment dispersant that can be used include higher fatty acid salts, alkyl sulfates, alkyl ester sulfates, alkyl sulfonic acids. Salt, sulfosuccinate, naphthalene sulfonate, alkyl phosphate,
Activators such as polyoxyalkylene alkyl ether phosphates, polyoxyalkylene alkyl phenyl ethers, polyoxyethylene polyoxypropylene glycol, glycerin esters, sorbitan esters, polyoxyethylene fatty acid amides, amine oxides, or polymers such as styrene. Block copolymer consisting of two or more kinds of monomers selected from styrene derivative, vinylnaphthalene derivative, acrylic acid, acrylic acid derivative, maleic acid, maleic acid derivative, itaconic acid, itaconic acid derivative, fumaric acid, fumaric acid derivative. Mention may be made of polymers, random copolymers and salts thereof.

Among these, those having a molecular weight (weight average molecular weight) of 3,000 or more are particularly preferable, and styrene, styrene derivatives, vinylnaphthalene derivatives, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, It is preferable to use a block dispersant composed of an itaconic acid derivative, fumaric acid, or a fumaric acid derivative, a block copolymer composed of two or more kinds of monomers, a random copolymer, or a salt thereof, and among them, 3 ，
Styrene, acrylic acid, having a molecular weight of 000 or more,
A block copolymer and a random copolymer selected from acrylic acid ester, methacrylic acid, methacrylic acid ester and the like are preferable. Examples of these include styrene-acrylic acid-methyl methacrylate copolymer (molecular weight 10,000
It has an acid value of 0, an acid value of 160), and acrylic-styrene resin such as John Cryl 61 (manufactured by Johnson Co.) is available.

The use of the polymer dispersant is considered to be because the electric double layer is firmly formed around the pigment particles and is stable, but it is difficult to be agglomerated and adhered, which is preferable in the present invention.

As a method for dispersing the pigment, for example, various dispersing machines such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill and a paint shaker can be used. it can. Also,
It is also preferable to use a centrifugal separator and a filter for the purpose of removing coarse particles of the pigment dispersion.

The average particle size of the pigment particles in the pigment ink is selected in consideration of stability in the ink, image density, glossiness, light resistance, etc. In addition, in the image forming method of the present invention,
From the viewpoint of improving gloss and improving texture, it is preferable to appropriately select the particle size. In the present invention, the reason why the glossiness or texture is improved is not clear at this stage, but in the formed image, the pigment is in a state in which it is preferably dispersed in the film in which the thermoplastic resin is melted. Presumed to be related to. For the purpose of high-speed treatment, it is necessary to melt the thermoplastic resin into a film in a short time and further sufficiently disperse the pigment in the film. At this time, it is considered that the surface area of the pigment has a great influence, and therefore the average particle size has an optimum region.

The water-based ink composition, which is a preferred form of the pigment ink, is preferably used in combination with a water-soluble organic solvent. Examples of the water-soluble organic solvent that can be used in the present invention include alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl). Alcohol, etc.), polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol,
Hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monoethyl ether Butyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.),
Amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine,
N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.),
Amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1, 3-dimethyl-2-imidazolidinone etc.), sulfoxides (eg dimethyl sulfoxide etc.), sulfones (eg sulfolane etc.), urea, acetonitrile, acetone and the like. Examples of preferable water-soluble organic solvent include polyhydric alcohols. further,
It is particularly preferable to use a polyhydric alcohol and a polyhydric alcohol ether together.

The water-soluble organic solvent may be used alone or in combination of two or more. The total amount of the water-soluble organic solvent added to the ink is 5 to 60% by mass, preferably 10 to
It is 35 mass%.

If necessary, the ink composition may be used in accordance with the purposes of improving ejection stability, compatibility with recording heads and ink cartridges, storage stability, image storability, and other performance improvements.
Various known additives, for example, viscosity modifier, surface tension modifier, resistivity modifier, film-forming agent, dispersant, surfactant,
Ultraviolet absorbers, antioxidants, anti-fading agents, antifungal agents, rust preventives and the like can be appropriately selected and used, for example, polystyrene, polyacrylic acid esters, polymethacrylic acid esters, polyacrylamides, polyethylene,
Polypropylene, polyvinyl chloride, polyvinylidene chloride, or copolymers thereof, organic latex particles such as urea resin or melamine resin, liquid paraffin, dioctyl phthalate, tricresyl phosphate, oil droplet particles such as silicone oil, cation or Various nonionic surfactants, JP-A-57-74193 and 57-
UV absorbers described in JP-A Nos. 87988 and 62-261476, JP-A-57-74192 and 57-879.
89, 60-72785, 61-146591.
And anti-fading agents described in JP-A-1-95091 and JP-A-3-13376, and JP-A-59-429993.
No. 59-52689, No. 62-280069,
61-242871 and JP-A-4-219266.
Examples thereof include fluorescent whitening agents, pH adjusting agents such as sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, etc.

The ink composition has a flying viscosity of preferably 40 mPa · sec or less, more preferably 30 mPa · s or less. The surface tension of the ink composition during flight is more preferably 30 to 35 mN / m so that the ink droplets spread uniformly on the recording medium.

The pigment solid content concentration in the ink is 0.1 to 1
In order to obtain a photographic image, it is preferable to use so-called dark and light inks having different pigment solid content concentrations, and as described above, yellow, magenta, cyan, and black light and dark inks are used. Is particularly preferable. In addition, it is also preferable from the viewpoint of color reproducibility to use special color inks such as red, green and blue, if necessary.

[0071]

EXAMPLES The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

Example Konica Inkjet Printer IGUAZU 104
The following tests were conducted using 4SD (schematic diagram is shown in FIG. 1).

(Production of Nozzle Plate A) A 125 μm-thick polyimide sheet (Ubilex manufactured by Ube Industries, Ltd.) was used and oxygen plasma treatment (13.56 MHz, 2
00W, 10 Pa, 3 minutes), and then a coating solution having the following composition is applied with a wire bar to a dry film thickness of 0.8 μm, and baked at 330 ° for the time shown below to perform an ink repellent treatment. To produce a nozzle plate.

FEP dispersion liquid (manufactured by Daikin Industries, Ltd., Neoflon ND-1) 10 parts by mass Silica sol particle dispersion liquid (manufactured by Catalysis Chemical Co., Ltd., Cataloid S-30H) 0.02 parts by mass Water 90 parts by mass Nozzle In order to evaluate the ink repellency of the plate surface,
Using a contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd., the receding contact angle was measured with the yellow ink 1 produced below, and it was 65 degrees.

The nozzle plate having been subjected to the ink repellent treatment was further processed with a nozzle hole by using an excimer laser. The number of nozzles was 128 and the nozzle diameter was 20 μm.

After forming the nozzle holes, a recording head was manufactured using the nozzle plate. Next, the manufactured recording head was mounted as a recording head of the Konica inkjet printer to manufacture an inkjet printer.
As the blades used for the maintenance unit, a silicone rubber having a thickness of 1 mm and a hardness of 50 degrees (Iruma Rubber Co., Ltd. IS-825 50HS), a silicone rubber having a hardness of 70 degrees (manufactured by Mitsuba Co., Ltd.) and a hardness of 5 were used.
A 0 degree urethane rubber (manufactured by Hokushin Kogyo Co., Ltd.) was replaced so that it could be used. Further, the overlapping of the blade and the nozzle surface (ink ejection surface) (d in FIG. 2A) can be performed by adjusting the mounting position of the blade to the blade supporting member 36 in three steps.

(Preparation of Inkjet Ink) As shown below, first, yellow (Y), magenta (M), cyan (C) and black (B) dye inks were prepared.

The prepared ink is 0.8
μm filter (DISMIC-25CS: Toyo
It was used after being filtered through Roshi Kaisha LTD.

[0079]   <Yellow ink 1>   Acid Yellow 42 5% by mass   Proxel GXL (D) (manufactured by Zeneca: 20% aqueous solution) 0.2% by mass   Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.05% by mass   Ethylene glycol 12 mass%   Diethylene glycol 13 mass%   Ion-exchanged water The balance is adjusted so that the total mass is 100g.   The surface tension was 33 mN / m.

[0080]   <Magenta ink 1>   Acid Red 249 3% by mass   Proxel GXL (D) (manufactured by Zeneca: 20% aqueous solution) 0.2% by mass   Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.05% by mass   Ethylene glycol 12 mass%   Diethylene glycol 13 mass%   Ion-exchanged water The balance is adjusted so that the total mass is 100g.   The surface tension was 32 mN / m.

[0081]   <Cyan ink 1>   Acid Blue 249 3.8% by mass   Proxel GXL (D) (manufactured by Zeneca: 20% aqueous solution) 0.2% by mass   Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.05% by mass   Ethylene glycol 12 mass%   Diethylene glycol 13 mass%   Ion-exchanged water The balance is adjusted so that the total mass is 100g.   The surface tension was 34 mN / m.

[0082]   <Black ink 1>   Acid Black 7 19% by mass   Proxel GXL (D) (manufactured by Zeneca: 20% aqueous solution) 0.2% by mass   Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.1% by mass   Ethylene glycol 12 mass%   Diethylene glycol 13 mass%   Ion-exchanged water The balance is adjusted so that the total mass is 100g.   The surface tension was 34 mN / m.

Four color dye inks prepared as described below were used as ink set 1. By the way, the surface tension of each ink was measured at a temperature of 25 ° C. using a CBVP type surface tensiometer A3 type manufactured by Kyowa Interface Science Co., Ltd.

Next, yellow (Y), magenta (M), cyan (C), and black (B) color water-based pigment inks were prepared according to the following formulations.

(Preparation of Pigment Dispersion) <Preparation of Yellow Pigment Dispersion> C.I. I. Pigment Yellow 74 20% by mass Styrene-acrylic acid copolymer (molecular weight 10,000, acid value 120) 12% by mass Diethylene glycol 15% by mass Ion-exchanged water 53% by mass Mixing the above additives, 0.3 mm zirconia beads Was dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 60% by volume to obtain a yellow pigment dispersion. The average particle size of the obtained yellow pigment is 1
It was 12 nm.

<Preparation of Magenta Pigment Dispersion> C.I. I. Pigment Red 122 25% by mass John Cryl 61 (acrylic-styrene resin, manufactured by Johnson Co.) Solid content 18% by mass Diethylene glycol 15% by mass Ion-exchanged water 42% by mass Mixing the above additives, 0.3 mm zirconia beads Was dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co.) filled with 60% by volume to obtain a magenta pigment dispersion. The average particle size of the obtained magenta pigment is 1
It was 05 nm.

<Preparation of Cyan Pigment Dispersion> C.I. I. Pigment Blue 15: 3 25% by mass John Cryl 61 (acrylic-styrene resin, manufactured by Johnson Co.) 15% by mass as solid content Glycerin 10% by mass Ion-exchanged water 50% by mass Add each of the above additives to obtain 0.3 mm Dispersion was performed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with zirconia beads at a volume ratio of 60% to obtain a cyan pigment dispersion. The average particle size of the obtained cyan pigment is 87n.
It was m.

<Preparation of Black Pigment Dispersion> Carbon black 20% by mass Styrene-acrylic acid copolymer (molecular weight 7,000, acid value 150) 10% by mass Glycerin 10% by mass Ion-exchanged water 60% by mass Each of the above additives Were mixed and dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) in which 0.3 mm zirconia beads were filled at a volume ratio of 60% to obtain a black pigment dispersion. The average particle size of the obtained black pigment is 7
It was 5 nm.

(Preparation of Pigment Ink) <Preparation of Yellow Ink 2> Yellow pigment dispersion 15% by mass Ethylene glycol 20% by mass Diethylene glycol 10% by mass Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.15% by mass Ion-exchanged water 54.9% by mass The above compositions are mixed, stirred, filtered through a 1 μm filter, and yellow ink 2 which is the aqueous pigment ink of the present invention.
Was prepared. The average particle size of the pigment in the ink is 120 nm
And the surface tension γ was 33 mN / m.

<Preparation of Magenta Ink 2> Magenta Pigment Dispersion 15% by mass Ethylene glycol 20% by mass Diethylene glycol 10% by mass Surfactant (Surfynol 465 Nisshin Chemical Industry Co., Ltd.) 0.1% by mass Ion-exchanged water 54.9 Mass% or more of each composition is mixed, stirred, filtered with a 1 μm filter, and magenta ink 2 which is the aqueous pigment ink of the present invention.
Was prepared. The average particle size of the pigment in the ink is 113 nm
And the surface tension γ was 35 mN / m.

<Preparation of Cyan Ink 2> Cyan Pigment Dispersion 10% by mass Ethylene glycol 20% by mass Diethylene glycol 10% by mass Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.15% by mass Ion-exchanged water 59.9 Mass% or more of each composition was mixed, stirred, and filtered with a 1 μm filter to prepare cyan ink 2, which is the aqueous pigment ink of the present invention. The average particle diameter of the pigment in the ink was 95 nm, and the surface tension γ was 32 mN / m.

<Preparation of Black Ink 2> Black pigment dispersion 10% by mass Ethylene glycol 20% by mass Diethylene glycol 10% by mass Surfactant (Surfynol 465, Nissin Chemical Industry Co., Ltd.) 0.1% by mass Ion-exchanged water 59.9 Mass% or more of each composition is mixed, stirred, filtered through a 1 μm filter, and black ink 2 which is the aqueous pigment ink of the present invention
Was prepared. The average particle size of the pigment in the ink was 85 nm, and the surface tension γ was 35 mN / m.

The ink set composed of the four colors of yellow ink 2 to black ink 2 prepared above was used as ink set 2.

For the Y, M, C, and B inks, yellow ink 3, magenta ink 3, cyan ink 3, and black ink 3 having surface tension of 25 mN / m by increasing the amount of Surfynol 465 are prepared. Ink set 3 was used.

Further, ethylene glycol and diethylene glycol, which are the solvents in the above pigment ink, are mixed with glycerin 1
Ink set 4 was prepared by preparing Yellow ink 4, Magenta ink 4, Cyan ink 4, and Black ink 4 in the same manner except that the amounts were changed to 4% by mass and 10% by mass of ethylene glycol. The surface tension of the ink is 41 and 4 respectively.
It was 2, 41, 44 mN / m.

As shown in Table 1, the ink cartridges of the respective printers in which the blades of the cleaning unit of the manufactured ink jet printer were made of silicone rubber having hardness of 50 degrees and 70 degrees, respectively, and urethane rubber (hardness of 50 degrees) were used. To each of the prepared ink sets 1 to
No. 4 was loaded, and cleaning tests 1 to 10 were performed for each ink set to check the durability of the blade by changing the overlapping of the blade and the nozzle surface of the printer and the sweep speed of the blade. In the cleaning test, after suctioning by a suction cap and wiping operation by a blade are repeated 30,000 times, the cover is opened and the wiping of ink on the nozzle surface of the recording head of the printer and the scratches on the nozzle surface due to the wiping operation are observed. . The change in the blade sweep speed (relative speed because the carriage actually moves) (90 mm / sec,
50 mm / sec, 10 mm / sec) was adjusted by adjusting the drive system of the cleaning unit of the printer.

<< Evaluation >> All evaluations were visually conducted.

<Ink wiping dust> ○ No ink droplets are found around the nozzle △ Some wiping dust is found around the nozzle and a little wiping dust is found × Ink droplets are clearly found around the nozzle <Nozzle surface damage> ○ No scratch is observed on the nozzle surface × The result of scratch on the nozzle surface is shown in Table 1.

[0099]

[Table 1]

From the results shown in Table 1, it can be seen that when the silicone blade is used under the conditions within the scope of the present invention, the silicone rubber is not deteriorated and wiping dust and scratches on the nozzle surface are small. Further, it can be seen that the applicability is high particularly in an ink having a relatively low surface tension (30 to 35 mN / m) using a pigment (insoluble coloring material).

[0101]

As is apparent from the above, according to the present invention, there is provided an ink jet recording apparatus and method which are free from unwiping residue by wiping and have improved ejection stability for a long time.

[Brief description of drawings]

FIG. 1 is a diagram showing an overlapping amount of a blade and a nozzle surface.

FIG. 2 is a diagram showing an overlapping amount of a blade and a nozzle surface.

FIG. 3 is a schematic diagram showing an example of a main configuration of an inkjet recording apparatus.

FIG. 4 is a schematic diagram showing a configuration of a recording head.

FIG. 5 is a configuration diagram showing an outline of an ink suction unit.

FIG. 6 is a schematic diagram showing a configuration of a wiping unit.

[Explanation of symbols]

1 Inkjet recording device 3 recording head 5 Maintenance unit 16 suction cap 17 blade

Continued front page    (72) Inventor Shoichi Kawabata             Konica Stock Market, 1 Sakura-cho, Hino City, Tokyo             In-house (72) Inventor Masaaki Takasaki             Konica Stock Market, 1 Sakura-cho, Hino City, Tokyo             In-house F-term (reference) 2C056 EA16 FA10 FC02 HA24 JA13                       JB02 JB04 JB09

Claims (4)

[Claims] 1. An ink jet recording apparatus having a mechanism for wiping a nozzle surface of a recording head using a blade, wherein the blade is a silicone blade having a hardness of 40 degrees or more and 60 degrees or less defined by JIS-K-6301. The inkjet recording apparatus is characterized in that the blade wipes the nozzle surface at a speed of 20 to 80 mm / sec, and the overlap between the nozzle surface and the blade is 1.0 mm or more and 2.0 mm or less. 2. The ink jet recording apparatus according to claim 1, wherein an ink having a surface tension of 30 to 35 mN / m is used. 3. The ink jet recording apparatus according to claim 1, wherein an ink containing an insoluble coloring material is used. 4. A recording method using the ink jet recording apparatus according to claim 1.