JP2003205621A - Inkjet printer and method of recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer and a method of recording using the same wherein entrainment during the wiping is reduced and a residual quantity of ink on a nozzle face after the wiping is small. <P>SOLUTION: In the inkjet printer having a wiping means of which a wiping speed is 25 mm/sec or more, a foaming force of ink is not greater than 100 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 printer having a wiping means for a nozzle surface of a recording head and a recording method using the same.

[0002]

2. Description of the Related Art While reciprocating a recording head having a plurality of nozzles to the left and right, ink droplets are ejected (discharged), and together with the movement of a support such as plain paper or special coated paper, a support is provided. Ink jet printers configured to form an image (pattern) according to image data are known.

Further, since ink jet recording is used for label printing, textile printing (cloth printing), color filter printing of liquid crystal panels and the like, the ink jet recording has a wide range of applications because of its characteristic that the recording medium is not limited.

In an ink jet printer, the nozzle surface of the recording head is used to recover ink clogging due to ink viscosity increase, ink sticking, or bubbles or dust generated in the liquid passage leading to the nozzle. Is covered with a cap member, and a suction pump is used to suck the dust through the cap member to remove dust and the like adhering to the nozzle surface.

Generally, when the cap member is removed from the recording head, many ink droplets remain on the nozzle surface. If these ink droplets remain on the nozzle surface, clear printing cannot be performed. For this reason, after removing the cap member, the nozzle surface is wiped and cleaned by bringing an elastic blade into contact with the nozzle surface.

However, when the nozzle surface is wiped off with a blade for cleaning (hereinafter also referred to as wiping), if ink droplets remain near the nozzles, the ink droplets will be pushed into the nozzles containing air, causing so-called bubble entrainment. In some cases, the print image may become unclear due to nozzle failure (defective ejection) or subsequent ejection failure such as ejection bending.

For this reason, studies have been conducted on the material of the blade, the wiping speed, the material of the nozzle surface, the shape of the discharge port of the nozzle surface, etc., but the effect is not sufficient. In particular, in an inkjet printer having a wiping unit having a wiping speed of 25 mm / sec or more, bubble entrapment is likely to occur, and a countermeasure against it has been required.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet printer in which bubbles are not entrained during wiping and the amount of ink remaining on the nozzle surface after wiping is small, and a recording method using the same.

[0009]

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

1. An inkjet printer having a wiping unit having a wiping speed of 25 mm / sec or more, wherein the ink used has a foaming force of 100 mm or less.

2. 2. The ink jet printer according to the above 1, wherein the wiping speed is equal to or lower than the backward meniscus speed (RMV) with respect to the nozzle surface of the recording head.

3. 3. The inkjet printer according to 1 or 2 above, wherein the driving frequency is 10 kHz or higher.

4. A recording method using the inkjet printer described in any one of 1 to 3 above.

The present invention will be described in detail below. The present invention relates to an inkjet printer having a wiping unit having a recording head wiping speed of 25 mm / sec or more, and a recording method using the inkjet printer.

Color inkjet printers typically
In order to correspond to the four colors of Y, M, C, and K, and the recent high image quality, there are cases in which dark and light inks are provided,
For all of these inks, it is necessary to suppress bubble entrainment in which air is entrained in the liquid path leading to the nozzle in the capping to wiping process and the amount of ink remaining on the nozzle surface after wiping.

In order to suppress bubble entrapment, the shape and material of the nozzle and the wiping blade, the wiping speed, the drive frequency of the recording head, etc. are related. However, in the inkjet printer of a maintenance time shortening type having a wiping speed of 25 mm / sec or more, it is not enough to adjust these conditions.

Further, in order to suppress the amount of ink remaining on the nozzle surface, it is effective to slow down the speed at which the cap member is disengaged from the nozzle surface of the recording head, but this has the problem of prolonging the maintenance time.

As a result of a detailed study of the capping to wiping process, the present inventor has found that the bubble entrainment, which is one of the physical properties of ink, is involved in bubble entrainment.
It has been found that when the foaming force measured by 1. is 100 mm or less, the bubble entrapment is greatly reduced, and at the same time, the residual ink amount is also reduced. Ink jet printers with fast wiping speeds and high drive frequencies generally have high bubble entrainment, but the reduced foaming power of the ink is particularly effective for this type of ink jet printer.

Further, the amount of ink remaining on the nozzle surface when wiping with this ink is related to the wiping speed, and decreases when the wiping speed is less than or equal to RMV determined by the physical properties of the ink and the physical properties of the nozzle surface. I found it.

In the ink jet printer according to the second aspect of the present invention, the wiping speed is changed from a safe speed for all inks to a higher speed according to the RMV determined by the ink used and the physical properties of the nozzle surface. The wiping can be efficiently performed, and the residual amount of ink and the maintenance time can both be achieved.

The embodiments of the present invention will be described below with reference to examples.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an inkjet printer 1.
It is a schematic diagram showing an example of the main composition of. An inkjet printer is a device for ejecting 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 (not shown) for conveying the recording paper 2 to the front during printing. ), A recording head (head) 3 for ejecting ink onto the recording paper 2, a carriage 4 for accommodating the recording head 3 for each of a plurality of colors, and a suction cap 16 and a blade portion 17 for performing 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, a home position 7 having a moisturizing cap 8 as a waiting place for the carriage 4, and each of these parts. And a control unit (not shown) that controls the above. C is an ink cartridge, and each ink sent from the ink cartridge C is temporarily stored in the sub-tank T, and then sent to the recording head through the supply valve V and the ink supply path P.

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

FIG. 2 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, a temperature sensor (temperature measuring means) 12 for measuring a temperature in the vicinity of the ink ejection main body 11, on a head substrate 10.
A flexible cable is connected, and a flexible cable connecting portion 13 for inputting / outputting signals to / from the ink discharge main body portion 11 and the temperature sensor 12 is installed. The drive frequency for ejecting ink is controlled by a controller (not shown) in the ink ejection main body 11. A plurality of ejection openings 14 for ejecting ink are provided in the ink ejection main body 11 along the center line of the surface (nozzle surface 15) facing the recording paper 2. The ejection openings 14 are nozzles. It communicates with (flow path). The recording head 3 is installed on the carriage 4 in a state in which one end of the nozzle surface 15 is inclined so as to be lower than the other end.

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

The maintenance unit 5 shown in FIG.
A suction cap (cap member) 16 that covers the ejection port 14 shown in FIG. 2 to suck the ink from the ejection port 14, and a blade that wipes the ink remaining on the nozzle surface 15 after the suction cap 16 sucks the ink The unit 17 and a blade cleaner unit (not shown in FIG. 1) for cleaning the blade unit are provided. 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. 3 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.

When the suction cap 16 is detached from the nozzle surface 15 after suction, it is detached from one end side first and gradually separated from 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.

In the present embodiment, the suction pump 20 is illustrated as the suction means, but 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 main body portion 23 for supporting the suction cap 16 and an extension portion 24 extending at a right angle from the lower end of the main body portion 23. The joint is pivotally supported at the joint. And
A substantially elliptical cam (moving means) 26 is in contact with the extending portion 24. By rotating the cam 26, the supporting piece 18
Is rotated, and the suction cap 16 is attached to and detached from the nozzle surface 15 of the recording head 3 accordingly.

The cam drive shaft 27 of the cam 26 is connected to a cam drive unit such as a motor, and is rotated under the control of the cam drive unit, so that the suction cap 16 is separated from the recording head 3 at a predetermined position ( It is moved between a standby position (FIG. 3C) and a position where the nozzle surface 15 is covered and sealed (FIG. 3A).

FIG. 4 is a schematic view showing the structure of a wiping unit including a blade and a blade cleaner section.
The blade portion 17 is formed of an elastic body, and the suction cap 1
After the end of the ink suction by 6, the blade main body 35 for wiping off the ink remaining on the nozzle surface 15 and the blade movable portion 36 for supporting the blade main body 35 and moving it up and down (arrow E) are provided.

Further, a blade cleaner portion 37 is installed inside the maintenance unit 5, and an ink absorber 38 for absorbing and wiping the ink of the blade body 35,
An absorber holding unit 39 that holds the ink absorber 38 is provided.

As shown in FIG. 1, the home position 7 is provided with a moisturizing cap 8 for moisturizing the nozzle surface 15.
The same number as the recording heads 3 are provided, and the nozzle surfaces 15 of the recording heads 3 are covered and hermetically sealed while the carriage 4 is on standby.

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

The carriage 4 is moved 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 moves to the nozzle surface 15 of the recording head 3 by the cam driving unit (not shown), and seals the nozzle surface 15 of the recording head 3. 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
Up to the blade part 17 for wiping
It is moved by the carriage drive.

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 portion 17 stops at the wipe position, the carriage moves to start wiping. The wiping speed at this time is variable and controlled by a control unit (not shown) in the carriage drive unit. In the present invention, the wiping speed is 25 mm / s.
A speed of ec or more and RMV or less, which is determined by the ink used and the physical properties of the nozzle surface, is preferable.

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 ink absorber 38 of the blade cleaner portion 37, as shown in FIG. 4A. When the nozzle surface 15 needs to be wiped, the blade movable unit 36 moves upward,
The blade body 35 is moved 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 ink remaining on the blade body 35 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 main body 35 due to residual ink.

Further, when the movable blade portion 36 moves up and the upper end portion of the blade body 35 reaches the nozzle surface passing position F, the carriage 4 operates, and the upper surface of the blade 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 upper surface of the blade body 35 and the nozzle surface 15 contact each other, so that 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.

In the ink jet printer having such a structure, according to the present invention, JIS K336 is used.
2 can be effectively wiped at a relatively fast speed according to the ink having a foaming force of 100 mm or less and the physical properties of the nozzle surface, and the amount of bubble entrapment, the amount of ink remaining on the nozzle surface after wiping, and the like. Both maintenance time can be achieved. The specific wiping speed can be set according to the RMV determined by the ink and the physical properties of the nozzle surface. The wiping speed can be made higher when using an ink having a large RMV than when using an ink having a small RMV. When the wiping speed exceeds RMV, the amount of entrainment and the amount of ink remaining on the nozzle surface after wiping increase, so the wiping speed is preferably RMV or less.

In the case of a multi-color printer, by combining it with ink having a large RMV, the wiping speed can be increased and the time required for maintenance can be shortened.

The RMV value of the ink is measured by the following method. (Method of measuring RMV value) Ink 2 on the same water repellent film as the nozzle surface
5 μl is hung down, and as shown in FIG. 5, a rubber member R (6 mmφ) having a hydrophilic lower surface and a water-repellent film are held at a distance of 1 mm, and ink is held while drawing a circle with a radius of 20 mm. , A constant peripheral velocity (v
mm / sec). Measure the maximum speed at which the ink follows the rubber by changing the peripheral speed. The following speed is the maximum speed at which no ink residue is visually observed on the locus of the rubber.

Further, if the speed at which the blade sweeps the nozzle surface is higher than RMV for the same reason as the speed at which the cap member is removed from the nozzle surface of the recording head, wiping residue can be left during cleaning, thus improving cleaning efficiency. It must be dropped or the contact pressure with the nozzle surface must be increased, which reduces the durability of the nozzle surface.
Therefore, in the inkjet printer according to the present invention, it is preferable that the RMVs of all the plurality of inks are 25 mm / sec or more. When considering as a color ink jet device, if it has ink of less than this value, slow down the speed of removing the cap member from the nozzle surface of the recording head, or accept the longer maintenance time, It is selected whether to avoid lengthening the maintenance time without slowing the speed of removing the cap member from the nozzle surface of the recording head, but in the latter case, ink is likely to remain on the nozzle surface of the recording head, Remaining ink around the print head (around the carriage)
In addition, the elasticity of the blade may cause the ink to scatter around and cause contamination of the linear encoder and the like, which is a problem for the entire printer, which is not preferable.

In order to make the nozzle surface of the recording head water-repellent (ink-repellent), normally, for example, the surface of the nozzle plate constituting the nozzle surface is treated to be water-repellent.

The nozzle surface is usually made of a material such as plastic such as polyester or polyamide, glass, ceramic, metal or the like, which is coated with a water repellent material, and an ink repellent surface is used.

Regarding the method of applying a water-repellent or ink-repellent coating so that ink does not adhere to the nozzle surface, for example, Japanese Patent Publication No. 52-24821 and Japanese Patent Laid-Open No. 56-286.
No. 2 discloses a coating of a material having a property of repelling ink, such as a fluororesin such as polytetrafluoroethylene (PTFE) or a silicone resin, which is disclosed in JP-A-57-72866.
No. 60-255441 and the like describe the use of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) as an ink repellent film. This FEP is polytetrafluoroethylene (PTF
While having a low surface energy (ink repellency) equivalent to that of E), the viscosity at the time of heating and melting is lower than that of PTFE,
When a uniform film is formed by applying an aqueous dispersion and heating and melting, a uniform film can be obtained at a temperature lower than that of PTFE in a short time,
Excellent film forming processability. In addition, Japanese Patent Laid-Open No. 2001-715
For No. 09, a method of mixing and coating an FEP aqueous dispersion liquid and a silica sol particle dispersion liquid, drying and baking at 300 to 400 ° C., and a method of using a fluorine-containing polysiloxane compound also in JP-A-10-505870 and the like. Etc. are described.

The blade for cleaning the nozzle surface on the front surface of the recording head (whether ink-philic (hydrophilic) or ink-repellent (water-repellent) may be used) is, for example, various types. It is selected from elastic materials such as rubber.
When a blade having a relatively hydrophilic property such as urethane rubber is used, the affinity allows the ink to be attracted and wiped off. However, due to its hydrophilicity, ink droplets may be drawn again (from the nozzle) to the cleaned nozzle surface, and the blade is rather made of a material having weak ink affinity and ink repellency. Is preferred. It is preferable that ink droplets are not pulled out from the nozzle, and the blade itself is less contaminated.

As a material for the ink-philic (hydrophilic) blade, urethane rubber, or a blade material such as butyl rubber is coated with a silane compound, or a hydrophilic polymer (for example, nylon, polyurethane, polyvinyl alcohol, etc.) is used. Examples thereof include those that have been made hydrophilic by so-called surface modification such as coating or subjecting the rubber surface to plasma treatment in advance. For example, a contact angle with ink of 40 degrees or less is selected.

Examples of the blade material having an ink-repellent and water-repellent surface include silicone materials such as silicone rubber, silicone resin, room temperature curable silicone resin, and room temperature curable organic modified silicone resin.
Further, a hydrophobic material for the surface of the plastic base material having elasticity is used, for example, a material made of a water-repellent polymer resin such as polytetrafluoroethylene or a material coated with these resins. Of these, silicone materials are preferred. When evaluated by the contact angle with respect to the ink, a material having a contact angle of 50 degrees or more is preferable. As the silicone rubber, for example,
Irumagawa Rubber Co., Ltd. IS-825 50HS etc. can be obtained.

In addition to the RMV of the ink, the contact angle is used to measure and evaluate the ink repellency of the nozzle surface (nozzle plate) 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. Since the surface area becomes very large relative to the mass when the droplet becomes small, the effect of surface tension becomes overwhelmingly larger than that of gravity. Therefore, the only force that affects the movement of the microdroplets is the surface tension (σ: mN / m). 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, θa≈θe is established in many systems. Since θr is a contact angle with respect to a surface already wet with a liquid, it greatly changes when an 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. The liquid does not spread,
In order to prevent the balls from becoming spherical and rolling, it is preferable to use a system in which the advancing contact angle θa is large and the receding contact angle θr is small.

<Measurement of advancing contact angle and receding contact angle> Co., Ltd.
It is measured 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 and the droplet is retracted to measure the receding contact angle.

In the ink jet printer according to the present invention, ink having a foaming power of 100 mm or less is used. The foaming force can be measured according to JIS K3362. The foaming power can be 100 mm or less by selecting the type or amount of the defoaming agent, the surfactant, and the water-soluble organic solvent.

The defoaming agent used for reducing the foaming power is not particularly limited, and commercially available products can be used. Examples of such commercially available products include KF96, 66, 69, KS68, 604, 607 manufactured by Shin-Etsu Silicone Co., Ltd.
A, 602, 603, KM73, 73A, 73E, 7
2, 72A, 72C, 72F, 82F, 70, 71, 7
5, 80, 83A, 85, 89, 90, 68-1F, 6
8-2F (trade name) and the like. The compounding amount of these compounds is not particularly limited, but 0.001-2
It is preferably blended in a mass%. Compounding amount 0.001
If it is less than 2% by mass, bubbles are likely to be generated during ink preparation, and it is difficult to remove small bubbles in the ink. If it exceeds 2% by mass, the generation of bubbles is suppressed. It may occur and the print quality may be deteriorated, so that it is preferably within the above range.

The surfactant and water-soluble organic solvent used for reducing the foaming power can be selected from the surfactants and water-soluble organic solvent described below and used.

Although an aqueous ink is used in the present invention,
Either type of ink, dye or pigment, may be used. The water-based ink is, for example, 10 per total mass of ink.
It is an aqueous inkjet ink containing water in an amount of not less than mass%.

As the colorant used in the ink, water-soluble dyes such as acid dyes, direct dyes, reactive dyes, disperse dyes, pigments and the like can be used.

In the present invention, it is preferable to use a pigment ink as the colorant. As the pigment used in the pigment ink, an insoluble pigment, an organic pigment such as a lake pigment, 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 74, C.I. I. Pigment Yellow 9
3, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 13
8 etc. are mentioned.

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 for these pigments if necessary, and examples of the pigment dispersant that can be used include higher fatty acid salts, alkyl sulfates, alkyl ester sulfates and 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.

As a method for dispersing the pigment, 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, gloss feeling, light resistance, etc. Is preferably selected as appropriate. 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). Alcohols, etc., polyhydric alcohols (eg ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol) , Thiodiglycol, etc.), polyhydric alcohol ethers (eg,
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 monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc., amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldie) Nolamine, 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. Furthermore, 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,
Examples thereof include fluorescent whitening agents, pH adjusting agents such as sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide and potassium carbonate described in JP-A-61-242871 and JP-A-4-219266. You can

The viscosity of the ink composition during flight is preferably 40 mPa · s or less, more preferably 30 mPa · s or less. The surface tension of the ink composition during flight is preferably 20 mN / m or more,
More preferably, it is 30 to 45 mN / m.

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 a so-called dark and light ink in which the pigment solid content concentration is changed. As described above, yellow, magenta,
It is particularly preferable to use cyan and black dark and light inks, respectively. Further, if necessary, it is also preferable in terms of color reproducibility to use special color inks such as red, green and blue.

[0082]

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

Example 1 (Production of Printer 1) A 125 μm-thick polyimide sheet (Ubilex, manufactured by Ube Industries, Ltd.) was used, and oxygen plasma treatment (13.56 MHz, 200 W, 10 Pa,
3 minutes), and then apply a coating solution having the following composition with a wire bar to a dry film thickness of 0.8 μm,
Nozzle plate A was prepared by performing an ink repellent treatment by firing for 2 hours.

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 Repellent Nozzle hole processing was performed on the ink-treated nozzle plate A using an excimer laser. Nozzle diameter is 40 μm
And

After forming the nozzle, a recording head using the nozzle plate A was prepared. Next, the ink jet printer IGUAZU 1044SD (schematic diagram shown in FIG. 1) manufactured by Konica was remodeled, the recording head was replaced with the recording head prepared above, and the wiping speed was 20 mm / sec.
(Fixed) and the driving frequency was set to 7 kHz (fixed) to manufacture the printer 1. The blade material for the maintenance unit is made of silicone rubber (Irumagawa Rubber Co., Ltd.).
Silicone rubber IS-825 50HS manufactured by K.K.

(Production of Printer 2) The printer 1 was modified to produce the printer 2 with a wiping speed of 10 to 100 mm / sec (variable) and a driving frequency of 5 to 50 kHz (variable).

(Preparation of Ink) (Preparation of Yellow Pigment Dispersion) C.I. I. Pigment Yellow 128 150 g Styrene-acrylic acid-methyl methacrylate copolymer 70 g (molecular weight 10,000, acid value 160) Ethylene glycol 100 g Glycerin 80 g Ion-exchanged water 200 g are mixed, and 0.3 mm zirconia beads are mixed at a volume ratio of 6
Dispersion was carried out using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0% to obtain a yellow pigment dispersion. The average particle size of the obtained yellow pigment dispersion is 125.
was nm. The average particle size is measured by Zetasizer 100.
0 (made by Malvern) was used.

(Preparation of Inks Y1 to 4) Yellow Pigment Dispersion 100 g Ethylene Glycol 200 g Diethylene Glycol 100 g Olfine 1010 (manufactured by Nissin Chemical Co., Ltd.) Proxel GXL (manufactured by Zeneca) 2 g or more Was made to be 1000 g with ion-exchanged water and passed through a 1 μm Millipore filter twice to prepare inks Y1 to Y4.

(Evaluation) Regarding inks Y1 to Y4 JIS
The foaming force was measured by K3362, and the bubble entrapment was further performed by the following method, and the ink residual property and the wiping time which is a part of the maintenance time were evaluated.

<Evaluation of Ejection Failure> The ink cartridges of the printers 1 and 2 are loaded with the above-prepared inks Y1 to Y4, and emitted at the drive frequency shown in Table 1, and printed every 5 m.
Wiping was performed at the speed shown in (1) and the emission state was visually observed for 2 hours, and the number of nozzles that could not maintain the normal emission state such as intermittent emission where emission sometimes disappeared and oblique emission where the emission direction was shifted obliquely was counted. The smaller the number of nozzles that cannot normally eject, the less bubble entrapment.

⊚: The number of nozzles that cannot eject is 0 ○: 1 to 2 nozzles that cannot be ejected Δ: 3 to 5 nozzles that cannot be ejected X: The number of nozzles that cannot emit is 6 or more.

<Evaluation of Unwiped Remaining> The ink cartridges of the printers 1 and 2 were loaded with the above-prepared inks Y1 to Y4, emitted at the drive frequency shown in Table 1, and printed at a speed shown in Table 1 every 5 m printing. Wiping was performed, the cover was opened, and the ink residual property on the nozzle surface of the recording head of the printer was observed and visually evaluated according to the following criteria.

⊚: No remaining ink droplets including minute ones on the nozzle surface and its periphery can be confirmed. ○: Very small ink droplets are seen on the nozzle surface and its periphery. ×: Nozzle surface and The remaining ink droplets can be clearly seen around it.

<Wiping Time> The time until the blade comes into contact with the nozzle surface, wipes, and comes off the nozzle surface (wiping time) was measured.

The results are shown in Table 1.

[0096]

[Table 1]

Example 2 (Preparation of Ink) (Preparation of Magenta Pigment Dispersion) C.I. I. Pigment Red 122 100 g John Cryl 61 (acrylic-styrene resin, manufactured by Johnson) 60 g Ethylene glycol 100 g Ion-exchanged water 130 g are mixed, and 0.3 mm zirconia beads are mixed at a volume ratio of 6
After dispersion using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0%, 20,000 rp
Centrifuging at m for 30 minutes gave a magenta pigment dispersion. The average particle size of the obtained magenta pigment dispersion is 35.
was nm.

(Preparation of Inks M1 and 2) Magenta Pigment Dispersion 140 g Diethylene Glycol 180 g Glycerin 80 g Emulgen 120 (manufactured by Kao Corporation) Amount of foaming degree shown in Table 1 Proxel GXL (manufactured by Zeneca) 2 g or more ion-exchanged Inks M1 and 2 were prepared by making 1000 g with water and passing through a 1 μm Millipore filter twice.

(Preparation of Cyan Pigment Dispersion) C.I. I. Pigment Blue 15: 3 250 g Jonkryl 61 150 g (solid content) (acrylic-styrene resin, manufactured by Johnson) Glycerin 100 g Ion-exchanged water 500 g are mixed, and 0.3 mm zirconia beads are mixed at a volume ratio of 6
Dispersion was performed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0% to obtain a cyan pigment dispersion. The average particle size of the obtained cyan pigment dispersion was 87 nm.

(Preparation of Inks C1 and C2) Cyan Pigment Dispersion 100 g Ethylene Glycol 300 g Diethylene Glycol Monobutyl Ether 100 g Pluronic L-44 (Asahi Denka Co., Ltd.) Deionized water is used in an amount not less than the foaming degree shown in Table 1. The ink was finished to 1000 g and passed through a 1 μm Millipore filter twice to prepare inks C1 and C2.

(Preparation of Black Pigment Dispersion) Carbon black 250 g Styrene-acrylic acid copolymer 100 g (solid content) (Molecular weight 7,000, acid value 150) Glycerin 100 g Ion-exchanged water 550 g are mixed to obtain 0.3 mm Zirconia beads in volume ratio of 6
A horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0% was used for dispersion to obtain a black pigment dispersion. The average particle size of the obtained black pigment dispersion is 75n.
It was m.

(Preparation of Inks K1 and 2) Black pigment dispersion 150 g Ethylene glycol 200 g Triethylene glycol monoethyl ether 50 g Perex OP-T (manufactured by Kao Corporation) 2 g Inks K1 and 2 were prepared by passing through a Millipore filter twice.

(Evaluation) With respect to each of the prepared inks, RMV was measured by the above-mentioned measuring method, and foaming force was measured by JIS K3362.

Next, the above-prepared ink was loaded into the ink cartridge of the printer 2 produced in Example 1, emitted at the drive frequency shown in Table 2, and wiped at the speed shown in Table 2 every 5 m printing. Otherwise, in the same manner as in Example 1, the emission failure and the uncleaned portion were evaluated.

The results are shown in Table 2.

[0106]

[Table 2]

[0107]

EFFECTS OF THE INVENTION It is possible to provide an ink jet printer in which bubbles are not entrained during wiping and the amount of ink remaining on the nozzle surface after wiping is small, and a recording method using the ink jet printer.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an example of a main configuration of an inkjet printer.

FIG. 2 is a schematic diagram showing a configuration of a recording head.

FIG. 3 is a configuration diagram showing an outline of an ink suction unit.

FIG. 4 is a schematic diagram showing a configuration of a wiping unit.

FIG. 5 is a diagram showing a method for measuring an RMV value.

[Explanation of symbols]

1 inkjet printer 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 EA15 EA16 EC22 EC23 FA10                       FC02 JA05 JA13 JA16 JB04                       JB09 JC08 JC20                 2H086 BA60

Claims (4)

[Claims] 1. An inkjet printer having a wiping unit having a wiping speed of 25 mm / sec or more, wherein the ink used has a foaming force of 100 mm or less. 2. The ink jet printer according to claim 1, wherein the wiping speed is equal to or lower than the backward meniscus speed (RMV) with respect to the nozzle surface of the recording head. 3. The inkjet printer according to claim 1, wherein the driving frequency is 10 kHz or higher. 4. A recording method using the ink jet printer according to claim 1.