JP2003191479A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder in which an amount of ink remaining at a nozzle face when a cap member separates from the nozzle face of a recording head is restricted, and the recording head can be efficiently maintained by separating the cap member from the nozzle face of the recording head at an optimum speed. <P>SOLUTION: In the ink jet recorder having the recording head and using a plurality of ink, there is set a capping means which can vary the speed for separating the cap member from the nozzle face of the recording head in accordance with the ink. <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 having a capping means for a nozzle surface of a recording head.

[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. An ink jet recording apparatus configured to form an image (pattern) according to image data thereon is 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 recording apparatus, nozzles of a recording head are used to recover ink clogging due to ink viscosity increase, ink sticking, or bubbles or dust generated in a liquid passage leading to the nozzle. Maintenance is performed by covering the surface with a cap member and suctioning a suction pump 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, if ink droplets remain near the nozzle before the nozzle surface is wiped off with a blade and cleaned, the ink droplets may be sucked into the nozzle including air when they are sucked into the nozzle due to a capillary phenomenon. In the subsequent printing, there is a risk that a printed image becomes unclear due to nozzle missing (ejection failure) or ejection failure such as ejection bending.

Therefore, for example, in a state where the nozzle surface is covered with the cap member, one end of the cap member starts to come off from the nozzle surface and gradually comes to the other end, or the recording head is set so that the nozzle surface faces downward. If the cap member covers the nozzle surface from below and the speed at which the cap member is disengaged from the nozzle surface is slowed, the ink droplets remaining on the nozzle surface may have a cohesive force of the ink, ink and the nozzle surface,
Due to the water-repellent phenomenon with the cap member, they gather along the nozzle surface and the cap member. Most of the ink droplets collect on the portion of the nozzle surface where the cap member comes off or on the cap member, so that it is possible to prevent ink droplets from remaining near the nozzle.
However, in this method, the operation of the cap member coming off the nozzle surface is delayed, and therefore the time required for maintenance of the recording head increases.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to suppress the amount of ink remaining on the nozzle surface when the cap member comes off the nozzle surface of the recording head, and to keep the cap member from the nozzle surface of the recording head at an optimum speed. An object of the present invention is to provide an ink jet recording apparatus that can perform maintenance of a recording head efficiently by being detached.

[0009]

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

1. An inkjet recording apparatus having a recording head and using a plurality of inks, further comprising a capping means capable of changing a speed of removing a cap member from a nozzle surface of the recording head by the inks.

2. In an inkjet recording apparatus that has a recording head and a capping unit and uses a plurality of inks, A is used when the ink having the largest receding meniscus velocity (RMV) with respect to the nozzle surface of the recording head is A and the smallest ink is B. An ink jet recording apparatus characterized in that a speed Va for removing the cap member from the nozzle surface of the recording head at this time is higher than a speed Vb for removing the cap member from the nozzle surface of the recording head when B is used.

3. 3. The ink jet recording apparatus according to the above 2, wherein the speed of removing the cap member from the nozzle surface of the recording head is RMV × 0.9 or less.

The present invention relates to an ink jet recording apparatus having a capping means for a nozzle surface of a recording head.

A color ink jet recording apparatus is usually
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 the amount of ink remaining on the nozzle surface when the cap member comes off the nozzle surface of the recording head. In order to suppress the amount of ink remaining on the nozzle surface, it is most effective to slow down the speed at which the cap member is disengaged from the nozzle surface of the recording head. Therefore, many inkjet recording apparatuses have conventionally required a long maintenance time.

As a result of detailed examination of the situation where the cap member comes off the nozzle surface of the recording head, the present inventor has found that the amount of ink remaining on the nozzle surface varies depending on the type of ink. More specifically, it was found that the limit speed at which ink droplets can be prevented from collecting on the nozzle surface portion where the cap member comes off and remaining in the vicinity of the nozzle is determined by the physical properties of the ink and the physical properties of the nozzle surface.

Since the ink jet recording apparatus according to the first aspect of the present invention has the capping means that can change the speed of removing the cap member from the nozzle surface of the recording head by ink, the cap member comes off the nozzle surface of the recording head. From speed that is safe for all inks,
The cap member can be efficiently removed from the nozzle surface of the recording head by changing the speed to a higher speed determined by the ink used and the physical properties of the nozzle surface, and the residual amount of ink and maintenance time can both be achieved.

In the ink jet recording apparatus according to the second aspect of the present invention, the RMV is determined by the ink and the physical properties of the nozzle surface.
Accordingly, the cap member can be removed from the nozzle surface of the recording head at a speed suitable for the ink.

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

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an inkjet recording apparatus 1.
It is a schematic diagram showing an example of the main composition of. 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 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 having the guide rail 6, 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 serving as a waiting place for the carriage 4, And a control unit (not shown) that controls each unit. 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 printing 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. 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 discharge port 14 communicates with the nozzle (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 discharge port 14 shown in FIG. 2 and sucks ink from the discharge port 14, and wipes ink that remains on the nozzle surface 15 after the suction cap 16 sucks ink. The blade portion 17,
Although not shown in FIG. 1, a blade cleaner unit for cleaning the blade unit is provided. Suction cap 16
Are arranged side by side (two in this embodiment), and it is possible to suck a plurality of recording heads 3 at a time 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, the suction cap 16 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.

Although the suction pump 20 is exemplified as the suction means in the present embodiment, any suction pump may be used as long as it sucks ink from the discharge 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 extending 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 by 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 section 37 is installed inside the maintenance unit 5, and an ink absorber 38 for absorbing and wiping off the ink of the blade body 35,
An absorber holding unit 39 that holds the ink absorber 38 is provided.

Further, as shown in FIG. 1, a moisturizing cap 8 for moisturizing the nozzle surface 15 is provided at the home position 7.
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 so that the recording head 3 is moved to the suction cap 1.
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 stops 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, the atmosphere communication valve 21 is subsequently 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.

Upon completion of the wipe, the blade portion 17 is cleaned by the blade cleaner portion 37.

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. 4 (a). 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 rises and the upper end 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 recording apparatus having such a structure, in the present invention, the cap member can be efficiently removed from the nozzle surface of the recording head at a relatively high speed according to the ink used and the physical properties of the nozzle surface. Can
It is possible to achieve both the residual amount of ink and the maintenance time. The specific speed can be set according to the RMV determined by the ink and the physical properties of the nozzle surface. The speed at which the cap member is removed from the nozzle surface of the recording head can be made higher when using ink having a large RMV than when using ink having a small RMV. When the speed at which the cap member is removed from the nozzle surface of the recording head is set higher than RMV, ink remains in island shapes on the nozzle surface and the cap member, so the speed is preferably RMV × 0.9 or less.

Further, in the case of a multi-color printer, it is necessary to set the speed for removing the cap member from the nozzle surface of the recording head in accordance with the ink that tends to remain on the nozzle surface, so it is combined with ink with a large RMV. As a result, the speed of removing from the nozzle surface of the recording head can be increased, and the time required for maintenance can be shortened.

Ink RMV (Receding Me)
The niscus velocity) value is measured by the following method.

(Method for measuring RMV value) 25 μl of ink was dripped on the same water repellent film as the nozzle surface, and as shown in FIG. 5, the distance between the hydrophilic rubber member R (6 mmφ) on the lower surface and the water repellent film was 1 mm. This member is held, and this member is rotated at a constant peripheral speed (vmm / sec) around the rotation axis while holding the ink so as to draw a circle with a radius of 20 mm. 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.

If the speed at which the blade sweeps the nozzle surface is set higher than the RMV value 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, and therefore cleaning efficiency can be improved. And the contact pressure with the nozzle surface must be increased, which reduces the durability of the nozzle surface. Therefore, in the ink jet recording apparatus according to the present invention, it is preferable that all of the plurality of inks be 20 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, In some cases, the remaining ink is repelled around the recording head (around the carriage) by the elasticity of the blade, causing the ink to scatter around and causing contamination of the linear encoder and the like, which is a problem for the entire printer. Not preferable.

In order to make the nozzle surface of the recording head water-repellent (ink-repellent), usually, for example, the nozzle plate surface constituting the nozzle surface is processed 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 has been subjected to a water repellent coating, and which has an ink repellent surface.

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 it is ink-philic (hydrophilic) or ink-repellent (water-repellent)) is, for example, various types of blades. 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 the 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 already
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 recording apparatus according to the present invention, an aqueous ink is used, but either dye or pigment type ink may be used. Cleaning the ink droplets remaining on the nozzle surface (nozzle plate) by suction, especially in the case of pigment ink, when the solvent or water evaporates,
Since the pigment is basically insoluble in the solvent and does not redissolve,
The ink jet recording apparatus according to the present invention is capable of efficiently cleaning the nozzle surface in a short time because it adheres as a hard mass and is taken into the nozzle, which tends to cause ejection failure, and also damages the nozzle surface and further the blade. Is particularly effective when a pigment ink is used.

In the present invention, the water-based ink is, for example, a water-based inkjet ink containing 10% by mass or more of water based on the total mass of the ink.

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

In the present invention, it is particularly preferable to use the pigment ink as the colorant, because it causes a larger problem in cleaning than the dye ink as described above. It is also preferable from the viewpoint of the storability of the obtained image record. 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 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.

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). 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 in combination.

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%.

The ink composition, if necessary, 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 properties.
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 ink composition has a flying viscosity of 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.

[0078]

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

Example 1 (Preparation of Printer 1) An oxygen plasma treatment (13.56 MHz, 200 W, 10 Pa) was performed using a 125 μm thick polyimide sheet (Ubilex, manufactured by Ube Industries, Ltd.).
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 Nozzle In order to evaluate the ink repellency of the surface of the plate A, a receding contact angle was measured with the ink Y1 prepared below using a contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd. The receding contact angle was 65 degrees.

Further, the nozzle plate A, which had been subjected to the ink repellent treatment, was subjected to nozzle hole processing using an excimer laser.
The nozzle diameter was 40 μm.

After forming the nozzle, a recording head using the nozzle plate A was prepared. Next, the ink jet printer IGUAZU 1044SD made by Konica (schematic diagram is shown in FIG. 1) is modified, the recording head is replaced with the recording head prepared above, and the speed of removing the cap member from the nozzle surface of the recording head is 40 mm / sec (fixed. ) Was manufactured as a 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) In the production of the printer 1, the speed at which the cap member is removed from the nozzle surface of the recording head is controlled to 5 to 100 mm / sec (variable) by controlling the rotational speed of the cam drive shaft 27 shown in FIG. 2), the printer 2 was manufactured in the same manner as the above.

(Preparation of Ink) (Yellow Pigment Dispersion 1) 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
Yellow pigment dispersion 1 was dispersed using a horizontal bead mill filled with 0% (System Zetamini manufactured by Ashizawa Co., Ltd.).
Got The average particle diameter of the obtained yellow pigment dispersion 1 is 1
It was 25 nm. The average particle size is measured by Zetasizer 1
000 (manufactured by Malvern Instruments Ltd.) was used.

(Yellow Pigment Dispersion 2) The yellow pigment dispersion 1 was centrifuged at 20,000 rpm for 30 minutes to obtain a yellow pigment dispersion 2. The average particle size of the obtained yellow pigment dispersion 2 was 75 nm.

(Preparation of Inks Y1 and Y2) (Ink Y1) Yellow Pigment Dispersion 2 167 g Ethylene glycol 200 g Diethylene glycol 120 g Olphin 1010 (manufactured by Nissin Chemical Co., Ltd.) 4 g Proxel GXL (manufactured by Zeneca) 2 g or more is ion-exchanged Ink Y1 was prepared by making 1000 g with water and passing it twice through a 1 μm Millipore filter.

(Ink Y2) Yellow Pigment Dispersion 1 100 g Ethylene glycol 200 g Diethylene glycol 100 g Olfine 1010 (manufactured by Nisshin Chemical Co., Ltd.) 4 g Proxel GXL (manufactured by Zeneca) 2 g or more is ion-exchanged water to 1000 g, and 1 μm Ink Y2 was prepared by passing it twice through a Millipore filter.

(Preparation of Magenta Pigment Dispersions 1 and 2) (Magenta Pigment Dispersion 1) C.I. I. Pigment Red 122 100 g Demol C 63 g Glycerin 100 g Ion-exchanged water 130 g are mixed, and 0.3 mm zirconia beads are mixed at a volume ratio of 6
Magenta pigment dispersion 1 was dispersed by using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0%.
Got The average particle size of the obtained magenta pigment dispersion 1 is 6
It was 5 nm.

(Magenta Pigment Dispersion 2) 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
Centrifugation treatment was performed at m for 30 minutes to obtain a magenta pigment dispersion 2. The average particle diameter of the obtained magenta pigment dispersion 2 was 35 nm.

(Preparation of Inks M1 and M2) (Ink M1) Magenta Pigment Dispersion 1 160 g Diethylene glycol 180 g Glycerin 80 g Perex OT-P (manufactured by Kao Corporation) 5 g Proxel GXL (manufactured by Zeneca) 2 g or more of ion-exchanged water Ink M1 was prepared by finishing the product to 1000 g and passing it twice through a 1 μm Millipore filter.

(Ink M2) Magenta Pigment Dispersion 2 140 g Diethylene glycol 180 g Glycerin 80 g Emulgen 120 (manufactured by Kao Corporation) 4 g Proxel GXL (manufactured by Zeneca) 2 g or more are deionized water to 1000 g, and a 1 μm Millipore filter is used. Ink M2 was prepared by two passes.

(Preparation of Cyan Pigment Dispersions 1 and 2) (Cyan Pigment Dispersion 1) C.I. I. Pigment Blue 15: 3 200 g Demol C (manufactured by Kao Corporation) 100 g Glycerin 80 g Ion-exchanged water 620 g are mixed, and 0.3 mm zirconia beads are mixed at a volume ratio of 6
Cyan pigment dispersion 1 was obtained by dispersing using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0%. The average particle size of the obtained cyan pigment dispersion 1 is 95 n.
It was m.

(Cyan Pigment Dispersion 2) 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
Cyan pigment dispersion 2 was obtained by dispersing using a horizontal type bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0%. The average particle size of the obtained cyan pigment dispersion 2 is 87 n.
It was m.

(Preparation of Inks C1 and C2) (Ink C1) Cyan Pigment Dispersion 1 150 g Diethylene glycol 150 g Triethylene glycol 200 g Perex OP-T (manufactured by Kao Corporation) 2 g Ion-exchanged water 498 g A 1 μm Millipore filter was used. Ink C1 was prepared by two passes.

(Ink C2) Cyan Pigment Dispersion 2 100 g Ethylene glycol 300 g Diethylene glycol monobutyl ether 100 g Pluronic L-44 (manufactured by Asahi Denka Co., Ltd.) 10 g Ion-exchanged water 490 g The above ink was passed through a Millipore filter of 1 μm twice. C2 was prepared.

(Preparation of Black Pigment Dispersions 1 and 2) (Black Pigment Dispersion 1) Carbon Black 250 g Vanilex RN (manufactured by Nippon Paper Industries Co., Ltd.) 200 g Diethylene glycol 100 g Ion-exchanged water 450 g are mixed, and 0.3 mm zirconia is mixed. 6 beads by volume
Black pigment dispersion 1 was dispersed using a horizontal bead mill filled with 0% (System Zetamini manufactured by Ashizawa Co., Ltd.).
Got The resulting black pigment dispersion 1 has an average particle size of 8
It was 3 nm.

(Black Pigment Dispersion 2) 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 were mixed, and 0.3 mm zirconia was mixed. 6 beads by volume
Black pigment dispersion 2 was dispersed using a horizontal bead mill (System Zetamini manufactured by Ashizawa Co., Ltd.) filled with 0%.
Got The average particle size of the obtained black pigment dispersion 2 is 7
It was 5 nm.

(Preparation of Inks K1 and K2) (Ink K1) Black Pigment Dispersion 1 150 g Ethylene glycol 300 g Rebenol WX (manufactured by Kao Corporation) 2 g Ion-exchanged water 548 g The above components are passed through a 1 μm Millipore filter twice. Ink K1 was prepared.

(Ink K2) Black pigment dispersion 2 150 g Ethylene glycol 200 g Triethylene glycol monoethyl ether 50 g Perex OP-T (manufactured by Kao Corporation) 2 g Ion-exchanged water 598 g The above components were passed twice through a 1 μm Millipore filter. Ink K2 was prepared.

In the ink cartridges of the printers 1 and 2,
The ink prepared above was loaded in combination with the ink sets 1 and 2, and the speed for removing the cap member from the nozzle surface of the recording head was 40 mm / sec for the printer 1.
(Fixed), 2 for printer 2 by ink set
After changing to 0 mm / sec and 30 mm / sec, cleaning with the cleaning unit, that is, suction with the cap member and subsequent wiping with the blade, the cover was opened and the ink residual property of the nozzle surface of the recording head of the printer was observed. . Also, of the maintenance time by the cleaning unit, the time required to remove the cap was measured.

The results are shown in Table 1. The ink retention was visually evaluated according to the following criteria.

⊚: No remaining ink droplets including fine particles on the nozzle surface and its surroundings can be confirmed at all ◯: Minute ink droplets are seen on the nozzle surface and its surroundings, though very slight ×: Nozzle surface and The remaining ink droplets can be clearly seen around it.

[0103]

[Table 1]

In the conventional printer 1 in which the speed of removing the cap member from the nozzle surface of the recording head cannot be changed, the ink residual property is good for the ink set 2, but the ink residual property is good for the ink set 1. It is bad. In the printer 2 of the present invention in which the speed at which the cap member is removed from the nozzle surface of the recording head can be changed by the ink, the ink residual property is good for the ink sets 1 and 2. Although the maintenance time of the printer 2 is slightly longer, it is within the allowable range.

Example 2 (Fabrication of Printer 3) In the fabrication of the printer 2 of Example 1, the same process was performed up to the oxygen plasma treatment in the process of producing the nozzle plate A, but the following coating liquid was used instead of the above. It was applied to a thickness of 0.8 μm and baked at 380 ° for 2 hours to prepare a nozzle plate B, which was used to prepare a printer 3. The speed of removing the cap member from the nozzle surface of the recording head is 5 to 1 in the same manner as the printer 2.
It was set to 00 mm / sec.

In order to evaluate the ink repellency of the surface of the nozzle plate B, the receding contact angle of the ink Y1 was measured using a contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd. The receding contact angle was 55 degrees.

FEP dispersion (manufactured by Daikin Industries, Ltd., Neoflon ND-1) 9.5 parts by mass Silica sol particle dispersion (catalyst chemical industry Co., Ltd., Cataloid S-30H) 0.5 parts by mass Water 90 parts by mass Then, the RMV on the surface of the nozzle plate B was measured for each of the prepared inks using the apparatus shown in FIG.

Next, each of the above-prepared inks is loaded into the ink cartridge of the printer 3, and the speed of removing the cap member from the nozzle surface of the recording head is changed within the range of 10 to 25 mm / sec according to the RMV of each ink. Example 1
Ink retentivity and maintenance time were evaluated in the same manner as in.

The results are shown in Table 2.

[0110]

[Table 2]

By setting the speed of removing the cap member from the nozzle surface of the recording head according to the RMV of the ink, the ink residual property is good and the maintenance can be performed efficiently. It can be seen that the ink having a larger RMV has a better ink retentivity even if the speed at which the cap member is removed from the nozzle surface of the recording head is higher, and the cleaning time can be shortened.

[0112]

The ink remaining amount on the nozzle surface when the cap member comes off the nozzle surface of the recording head is suppressed, and
It is possible to provide an inkjet recording apparatus capable of efficiently performing maintenance of the recording head by removing the cap member from the nozzle surface of the recording head at an optimum speed.

[Brief description of drawings]

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

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 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 EA01 EA17 EB07 EB30 EC22                       EC23 EC31 FC02 HA24 JA03                       JA05 JA13 JB02 JB04 JB09                       JC07 JC13

Claims (3)

[Claims] 1. An inkjet recording apparatus having a recording head and using a plurality of inks, comprising an capping means capable of varying a speed at which a cap member is detached from a nozzle surface of the recording head by the inks. Recording device. 2. In an inkjet recording apparatus having a recording head and a capping means and using a plurality of inks, the ink having the largest receding meniscus velocity (RMV) with respect to the nozzle surface of the recording head is A and the smallest ink is B. In this case, the inkjet recording apparatus is characterized in that the speed Va for removing the cap member from the nozzle surface of the recording head when using A is higher than the speed Vb for removing the cap member from the nozzle surface of the recording head when using B. 3. The ink jet recording apparatus according to claim 2, wherein the speed of removing the cap member from the nozzle surface of the recording head is RMV × 0.9 or less.