JP2003072192A - Ink jet printing method and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printing method in which digital image data can be dealt with and different images can be printed clearly and inexpensively on a print medium at high speed. SOLUTION: In an ink jet printing method for forming an image directly on a print medium by ink jet system ejecting oil ink utilizing an electrostatic field based on the signal of image data and producing a printed matter by fixing that image, dust on the print medium M is suction removed by rolling an adhesive roller 2 on the print medium M before and/or during formation of the image on the print medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method for directly forming a printed image on a printing medium, and more specifically, an electrostatic ink jet using an oil-based ink by adsorbing and removing dust on the printing medium. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet printing method and a printing apparatus that have good print image quality by recording and can perform high-speed printing.

[0002]

2. Description of the Related Art As a printing method for forming a print image on a print medium based on an image data signal, there are an electrophotographic method, a sublimation type and a fusion type thermal transfer method, an ink jet method and the like. The electrophotographic method requires a process of forming an electrostatic latent image on a photosensitive drum by charging and exposing, and the system becomes complicated and becomes an expensive apparatus. The thermal transfer method is inexpensive in apparatus, but uses an ink ribbon, so the running cost is high and waste materials are generated. On the other hand, the ink jet system is an inexpensive device and ejects ink only to a necessary image portion to directly print on a printing medium, so that a coloring agent can be efficiently used and a running cost is low.

As a method of applying the ink jet technology to a printing system, for example, in Japanese Unexamined Patent Publication No. 10-286939, an ink jet printing apparatus is attached to a rotary printing machine, and variable numbers and marks are added on the same printing paper. A method of printing with an inkjet system is disclosed. However, it is more preferable that high-level image information such as a photographic image can be printed. However, in the conventional ink technology in which a water-based or organic solvent-based ink containing a dye or pigment as a colorant is ejected by using pressure, droplets containing a large amount of solvent are ejected, so printing is required unless expensive special paper is used. There is a drawback that the image is blurred. Therefore, when printing on ordinary printing paper or a plastic sheet which is a non-absorbent medium, a high-quality printed image cannot be obtained.

Further, as one of the ink jet technologies,
There is a method in which an ink in a solid state is melted by heating at room temperature and a liquid ink is ejected to form an image. When this ink is used, the bleeding of the printed image is reduced, but since the viscosity of the ink during ejection is high, it is difficult to eject minute droplets,
The obtained individual dot image has a large area and becomes thick, and it is difficult to form a high-definition image.

Further, in order to obtain a high-quality image, it is necessary to keep the ejection state of the ink jet in good condition. However, as the head is used, dust adhering to the print medium adheres to and accumulates on the recording head, and if a failure such as clogging of the recording head occurs, printing stains or the like may occur.
It is difficult to obtain a clear image.

[0006]

The present invention has been made in view of the above problems, and an object thereof is to print a printed matter of a clear and high quality image with an inexpensive device and a simple method. It is to provide an ink jet printing method that enables, in particular, by printing dust with a cheap device and a simple method from a printing medium used at that time, it is possible to print a printed matter with a clear and high-quality image at all times. To do.

[0007]

In order to achieve the above object, according to the invention of the ink jet type printing method described in claim 1, the oil-based ink is ejected by utilizing the electrostatic field based on the signal of the image data. In the inkjet printing method, in which an image is directly formed on a print medium by an inkjet method, and the printed matter is fixed by fixing the image, an adhesive property is formed before and / or during image formation on the print medium. It is characterized in that the roller is rolled on the print medium to adsorb and remove dust on the print medium. According to the second aspect of the invention, the adhesive force of the adhesive roller is 4 hPa or more and 250 hPa or less. In the ink jet printing method, the oil-based ink has a specific electric resistance value of 10 ⁹ Ωcm.
It may be characterized in that at least colored particles are dispersed in a non-aqueous solvent having a dielectric constant of 3.5 or less. Further, according to the invention of the printing apparatus of claim 3, an image forming means for directly forming an image on a printing medium based on an image data signal, and a printed matter by fixing the image formed by the image forming means. An image fixing unit that obtains the image forming unit, wherein the image forming unit is an inkjet drawing device that discharges an oil-based ink from a recording head by using an electrostatic field, in the printing medium moving direction upstream side of the inkjet drawing device. An adhesive roller for adsorbing and removing dust on the print medium is arranged so as to be rollable on the print medium. According to the invention of claim 4,
The adhesive force of the adhesive roller is 4 hPa or more and 250 h or more.
It is characterized by being Pa or less. In addition, claim 5
According to the invention described above, the adhesive roller is composed of two or more adhesive rollers having different adhesive forces, one adhesive roller is rolled on the print medium, and the adhesive force is larger than the adhesive force of the one adhesive roller. Another adhesive roller having an adhesive force is brought into contact with the one adhesive roller. Further, the printing apparatus may be characterized in that the oil-based ink is one in which at least colored particles are dispersed in a non-aqueous solvent having a specific electric resistance value of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less. Further, the printing device performs drawing by moving the print medium by rotating an opposed drum arranged at a position facing the recording head through the print medium when drawing on the print medium. It may be characterized. Further, the printing apparatus may be characterized in that the recording head is a single-channel head or a multi-channel head, and draws by moving the head in the axial direction of the opposing drum. Furthermore, the printing apparatus holds the print medium by at least a pair of cap stun rollers and causes the print medium to travel when drawing on the print medium,
It may be characterized by performing drawing. The printing apparatus may be characterized in that the recording head is a single-channel head or a multi-channel head, and draws by moving the recording head in a direction orthogonal to the traveling direction of the print medium. . Further, the printing apparatus may be characterized in that the recording head is a full line head having a length substantially the same as the width of the print medium. Further, the printing apparatus may be characterized in that the inkjet drawing apparatus has an ink supply unit that supplies the oil-based ink to the recording head. In addition, the printing apparatus may have an ink recovery unit that recovers the oil-based ink from the recording head, and circulates the ink. Further, the printing apparatus may be characterized in that the inkjet drawing apparatus has a stirring unit that stirs the oil-based ink in an ink tank that stores the oil-based ink. And, in the printing device, the inkjet drawing device is
It may be characterized by having an ink temperature management means for managing the temperature of the oil-based ink in the ink tank storing the oil-based ink. Further, the printing apparatus may be characterized in that the inkjet drawing apparatus has an ink density control unit that controls the density of the oil-based ink.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The present invention is characterized by removing dust adhering to the print medium in an inkjet method of ejecting an oil-based ink onto a print medium supplied to a printing apparatus by an electrostatic field.

The ink jet method according to the present invention is a PC
T publication WO 93/11866, and in this inkjet method, in an insulating solvent,
An ink having a high resistance in which at least colored particles are dispersed is used, and a strong electric field is applied to the ink at the ejection position to form an aggregate of the colored particles at the ejection position, and the aggregation is performed by electrostatic means. The object is ejected from the ejection position. In this way, the colored particles are ejected as a high-concentration aggregate, and the ink droplets contain only a small amount of solvent. As a result, there is no bleeding on the printing paper used as the recording medium or the printing plastic film,
A high density and clear image is formed. Further, in the inkjet method, the size of the ejected ink droplet is determined by the size of the tip of the ejection electrode or the electric field forming condition. Therefore, if a small ejection electrode and an appropriate electric field forming condition are used, a small ink droplet can be obtained without reducing the ejection nozzle diameter or the slit width. Therefore, a minute image can be controlled without the problem of ink clogging of the head, and the present invention provides an inkjet printing method capable of printing a printed matter of a clear and high-quality image.

A configuration example of a printing apparatus used for carrying out the ink jet printing method of the present invention is shown below. However, the present invention is not limited to the configuration examples below.

FIGS. 1 to 6 are diagrams showing a schematic configuration example of a printing apparatus for performing drawing by moving a print medium by rotating an opposed drum according to the present invention. 1 to 4 are diagrams showing a schematic configuration example of a Web-type printing apparatus in which a roll-shaped print medium is stretched around an opposed drum, a print medium supply roll, and a print medium winding roll or a guide roll. Figure 1
Is a web-type device for printing single-sided single color, and FIG. 2 is a web-type device for performing single-sided four-color printing. FIGS. FIG. 5 is a diagram showing a schematic configuration example of a single-sided four-color printing device that cuts a roll-shaped printing medium and winds it around an opposed drum, and FIG. 6 shows a schematic of a printing device using a sheet-shaped recording medium. It is a figure which shows the structural example. On the other hand, FIG. 7 and FIG. 8 are diagrams showing a schematic configuration example of a printing device for performing drawing by nipping a printing medium with a cap stun roller and running the same, of which FIG. FIG. 8 is a diagram showing a schematic configuration example of a printing apparatus using a printing medium, and FIG. 8 is a printing apparatus using a sheet-shaped recording medium. Each of the printing devices shown in FIGS.
Commonly, the adhesive roller 2 is installed according to the present invention. Although the adhesive roller 2 will be described later, the adhesive roller rolls on the print medium before and / or during image formation on the print medium to adsorb and remove dust on the print medium. is there. FIG. 9 is a schematic configuration example of a drawing device including a control unit, an ink supply unit, and a head separation / contact mechanism of the drawing device. Further, FIGS. 10 to 16 are for explaining the ink jet recording apparatus included in the drawing apparatus of FIG.

First, the printing process according to the present invention will be described with reference to the overall configuration diagram of the apparatus for single-sided single-color printing on the roll-shaped printing medium shown in FIG. The inkjet printing apparatus (hereinafter, also referred to as “printing apparatus”) shown in FIG. 1 is provided at a position facing a supply roll 1, a pressure-sensitive adhesive roller 2, a drawing device 3, and a drawing device 3 of a roll-shaped printing medium via a printing medium. It is composed of an opposed (drawing) drum 4, a fixing device 5, and a print medium take-up roll 6 which are arranged. After the dust and the like on the print medium sent from the supply roll is removed by the adhesive roller 2, the ink is ejected onto the print medium from the ink discharge section (described later) of the drawing device 3 toward the print medium on the drawing drum 4. It is ejected imagewise and a printed image is recorded. After fixing this image on the print medium using the fixing device 5, the printed print medium is wound around the print medium winding roll 6.

The facing (drawing) drum 4 is a roll made of a metal or a roll having a conductive rubber layer on the surface to serve as a counter electrode for the discharge electrode of the ink discharge portion, or an insulating drum made of plastic, glass, ceramics or the like. The one having a metal layer provided on the surface by vapor deposition, plating or the like is used. As a result, an effective electric field can be formed between the drawing unit 3 and the ejection unit. It is also effective to improve the image quality of drawing by providing the drawing drum 4 with heating means and raising the drum temperature. Bleeding is further suppressed because the ejected ink droplets are promptly fixed on the print medium. Further, by keeping the drum temperature constant, the physical properties of the ejected ink droplets on the print medium are controlled, and stable and uniform dot formation is possible. It is more preferable that a cooling means is also provided in order to keep the drum temperature constant.

In the ink jet printing apparatus, an adhesive roller 2 for adsorbing and removing dust on the printing medium is arranged on the upstream side of the drawing apparatus 3 in the moving direction of the printing medium so as to be rollable on the printing medium. . The term "rolling" as used herein means that the pressure-sensitive adhesive roller 2 makes contact with the print medium and moves relative to the print medium while rotating (including driven rotation or rotation). In the configuration of the present embodiment, the adhesive roller 2 rotates at a fixed position with respect to the rotating print medium, so that the adhesive roller 2 and the print medium move relatively.

The adhesive roller 2 can be contacted with and separated from the print medium by a separation / contact mechanism (not shown). The adhesive roller 2 removes dust existing on the surface of the print medium before and / or during drawing on the print medium. That is, the dust on the print medium may be removed only before drawing, only during drawing, before drawing, or during drawing. The adhesive roller 2 can be formed, for example, by applying an adhesive layer on the outer periphery of a cylindrical core material made of metal. Examples of the adhesive layer include rubber adhesives and acrylic adhesives. The pressure-sensitive adhesive roller 2 is determined by a method in accordance with "Test for bonding two parallel metal plates with rubber" in the section "Adhesion test between metal and vulcanized rubber" of JIS-K6301 vulcanized rubber physical test method. Adhesive force of 4hPa or more 250h
It is preferably Pa or less, more preferably 7
It is not less than hPa and not more than 180 hPa. As Table 1 shows the adhesive strength of the adhesive roller 2 and the result of performance evaluation, it is almost impossible to remove dust at 4 hPa or less, and the adhesive roller 2 cannot be used. When 4 hPa or more, the dust removing effect is observed, but when 7 hPa or more, the effect is further improved. Further, when the adhesive roller 2 having a pressure of 250 hPa or more is used, there arises a problem that the print medium is broken, the print medium is wrinkled, or conveyance is poor. When it is 250 hPa or less, it can be used, but when it is 180 hPa or less, the above-mentioned problems do not occur, and the quality level at the time of printing is further improved.

[0016]

[Table 1]

The pressure-sensitive adhesive roller 2 may be composed of one pressure roller or two or more pressure-sensitive adhesive rollers having different adhesive strengths. In this embodiment, the adhesive roller 2 is composed of two adhesive rollers 2a and 2b. In such a configuration, one adhesive roller 2a is rolled on the print medium, and the other adhesive roller 2b is brought into direct or indirect contact with this one adhesive roller 2a, so that one adhesive roller 2a is formed. The dust adhering to is adsorbed and removed.

Here, "directly" means another adhesive roller 2b.
Is a configuration (this embodiment) in which the roller is directly rolled on the adhesive roller 2a. Therefore, when there are two or more adhesive rollers 2b, a plurality of adhesive rollers 2b are added to the adhesive roller 2a.
Will be in contact at the same time. Further, “indirectly” means a configuration in which the adhesive rollers 2b are contacted in series when the number of the adhesive rollers 2b is two or more. Therefore, in the case of this mechanism, one adhesive roller 2b always contacts the adhesive roller 2a. Then, the adhesive force of the adhesive roller 2b is set to be larger than the adhesive force of the adhesive roller 2a.
That is, the adhesive roller 2b works as a cleaning roller for the adhesive roller 2a. In the case where there are two or more adhesive rollers 2b and the adhesive rollers 2b (adhesive rollers 2b1, 2b2, 2b3, ...) Are contacted in series, the adhesive force is 2b1 <2b2 <2.
b3 <...

According to the former direct contact, the dust on the adhesive roller 2a can be adsorbed and removed simultaneously by the plurality of adhesive rollers 2b. Further, according to the latter indirect contact, the dust adhering to the adhesive roller 2a can be sequentially adsorbed and removed by the other adhesive roller 2b, and the adhesive can always be adhered by the clean adhesive roller 2b to which no dust is attached. The dust on the roller 2a can be adsorbed and removed, the ability to adsorb and remove dust can be maintained for a long time, and reverse adhesion from the adhesive roller 2a to the print medium can be reliably prevented.

Further, the drawing device 3 has an ink jet recording device 20 as shown in FIG. In the inkjet recording device 20, an oil-based ink is ejected onto the print medium by an electrostatic field formed between the recording head 22 and the opposed drum 4 in response to the image data sent from the image data calculation control unit 21. , Form a drawn image.

The image data arithmetic control unit 21 receives image data from an image scanner, a magnetic disk device, an image data transmission device, etc., and performs color separation, and an appropriate number of pixels and gradation for the separated data. Divide into a number and distribute to each head. Furthermore, the inkjet recording device 2
In order to convert the oil-based ink image into halftone dots using the inkjet recording head 22 (see FIG. 10 described later) of No. 0, the halftone dot area ratio is also calculated.

As will be described later, the image data calculation control section 21 controls the movement of the ink jet head 22 and the ejection timing of the oil-based ink, and also controls the printing medium operation timing as necessary.

The printing process performed by the printing apparatus will be described in detail below with reference to FIGS. 1 and 9.

The print medium fed from the print medium supply roll is tensioned by the drive of the print medium take-up roll and abuts on the drawing (opposing) drum. As a result, it is possible to prevent the print medium web from vibrating and coming into contact with and damaging the ink jet recording apparatus during drawing. Further, a means for bringing the print medium into close contact with the drawing (opposing) drum only around the drawing position of the ink jet recording apparatus is provided, and at least when drawing is performed, this means is acted to prevent the print medium from contacting the ink jet recording apparatus. It can also be prevented. Specifically, for example, pressing rollers are arranged upstream and downstream of the drawing position of the drawing drum,
It is effective to use a guide or electrostatic attraction.

Image data from the magnetic disk device, etc.
The image data calculation control unit 21 is supplied to the image data calculation control unit 21, and calculates the ejection position of the oil-based ink and the halftone dot area ratio at that position according to the input image data. These calculation data are temporarily stored in the buffer. The image data calculation control unit 21 brings the recording head 22 closer to a position closer to the print medium that contacts the drawing drum by the head separating / contacting device 31. The distance between the recording head 22 and the surface of the drawing drum is controlled by a mechanical distance control such as a contact roller.
Alternatively, the distance from the head is maintained at a predetermined distance during drawing by controlling the head separation / contact device based on a signal from the optical distance detector. A single-channel head, a multi-channel head, or a full line head can be used as the recording head 22. When using a single-channel head or multi-channel head as the recording head,
The ejection unit is arranged in a direction substantially parallel to the running direction of the print medium, and main scanning is performed by moving the recording head in the axial direction of the opposing drum, and sub-scanning is performed by rotating the opposing drum to perform printing. The movement control of the opposing drum and the recording head described above is performed by the image data calculation control unit 21, and the recording head discharges the oil-based ink onto the print medium at the discharge position and the dot area ratio obtained by the above calculation. This allows
On the print medium, a halftone image corresponding to the shade of the print original is drawn with the oil-based ink. This operation continues until a predetermined ink image is formed on the print medium. On the other hand, the recording head 2
When 2 is a full line head having a length substantially the same as the width of the drum, the direction of arrangement of the discharge units is set substantially perpendicular to the running direction of the print medium, and the rotation of the opposing drum causes the print medium to form the drawing unit. By passing, an oil-based ink image is formed and a printed matter is completed.

After the printing is completed, the recording head 22 is retracted as necessary to protect the recording head 22 from a position close to the drawing drum. At this time, only the recording head 22 may be separated and contacted, but the recording head 22 and the ink supply unit 24 may be separated and contacted together.

The separating / connecting means operates so that the recording head is separated from the drawing drum by at least 500 μm or more except during drawing. The detaching / attaching operation may be a slide type, or the head may be fixed by an arm fixed to a certain axis and the arm may be moved around the axis to move like a pendulum. By retracting the head during non-writing as described above, the head can be protected from physical damage or contamination and a long life can be achieved.

The formed oil-based ink image is strengthened by the fixing device 5. As the ink fixing means,
Known means such as heat fixing and solvent fixing can be used. In the heat fixing, irradiation with an infrared lamp, a halogen lamp or a xenon flash lamp, or hot air fixing using a heater, or heat roll fixing is generally used. Flash fixing using a xenon lamp or the like is known as a fixing method for electrophotographic toner, and has an advantage that fixing can be performed in a short time. When laminated paper is used, moisture inside the paper evaporates rapidly due to a rapid temperature rise, and development called blister that causes irregularities on the paper surface occurs. In order to prevent blisters, it is preferable to change the power supply and / or the distance to the recording medium of the fixing device so that the temperature gradually rises.

In the solvent fixing, a solvent capable of dissolving the resin component in the ink, such as methanol or ethyl acetate, is sprayed or exposed to vapor, and excess solvent vapor is collected. In addition, at least during the process from the formation of the oil-based ink image by the recording head 22 to the fixing by the fixing device 5, it is desirable to keep nothing on the image on the print medium.

2 to 4 show examples of the configurations of single-sided and double-sided four-color printing apparatuses. In FIG. 4, 2c indicates a pressing roller. The pressing roller 2c can be contacted with and separated from the pressing roller 2c by a separation / contact mechanism (not shown), and may be fixed at a fixed position. Further, the pressing roller 2c may be driven by the adhesive roller 2 and may rotate in synchronization with the adhesive roller 2. With the adhesive roller 2 provided with the pressing roller 2c,
Even in the case of a printing apparatus that does not have the drawing drum 4, it is possible to reliably remove dust on the printing medium while pressing the adhesive roller 2 onto the printing medium. The principle of operation in the other configuration examples and the like can be easily inferred from the above description of the single-sided single-color printing apparatus, and thus the description thereof will be omitted. Further, although the configuration example of the four-color printing device is shown here, the number of colors is not limited to this, and the number of colors is arbitrarily determined as necessary.

FIGS. 5 and 6 show another example of the structure according to the present invention, which is an explanatory view of a printing apparatus which has an automatic ejecting device 7 and which is used by winding a print medium around an opposed drum. Figure 6
Is an example of a device configuration using a sheet-shaped print medium having an automatic supply device 9. Here, description will be given using an example of a device configuration using the roll-shaped print medium in FIG.

First, the print medium supply roll 1 is mounted on the opposing drum.
The print medium that has been pulled out by the cutter and cut into an arbitrary size by the cutter 8 is mounted. At this time, the known seat head /
The print medium is tightly fixed on the drum by a mechanical method such as a tail gripping device or an air suction device, or an electrostatic method, which causes the bottom of the paper to flutter and contact the ink ejection drawing device 3 at the time of drawing to damage it. Can be prevented. Further, a means for bringing the print medium into close contact with the drum is provided only around the drawing position of the ink ejection drawing device, and at least when drawing is performed, this is made to act to prevent the print medium from contacting the ink jet recording device. You can also Specifically, for example, there is a method of arranging a pressing roller upstream and downstream of the drawing position of the opposing drum. Furthermore, when drawing is not performed, it is desirable to keep the head away from the print medium, which can effectively prevent the occurrence of problems such as contact damage in the ink ejection drawing device.

A single-channel head, a multi-channel head, or a full-line head can be used as the recording head 22, and main scanning is performed by rotating the opposed drum 4. In the case of a multi-channel head or a full line head having a plurality of ejection parts, the ejection parts are arranged in the axial direction of the opposing drum 4. Further, in the case of a single-channel head or a multi-channel head, the image data calculation control unit 21 moves the head 22 continuously or sequentially in the axial direction of the opposing drum to obtain the calculation by the image data calculation control unit 21. The oil-based ink is discharged onto the print medium mounted on the drum 11 at the discharge position and the halftone dot area ratio. As a result, on the print medium, a halftone image corresponding to the shade of the print original is drawn with the oil-based ink. This operation continues until the desired oil-based ink image is formed on the print medium. On the other hand, when the recording head 22 is a full line head having a length substantially the same as the width of the drum, one rotation of the drum forms an oil-based ink image on the print medium to complete a printed matter. By performing the main scanning by rotating the drum in this way, it is possible to improve the position accuracy in the main scanning direction and perform high-speed drawing. The printed printing medium is fixed by the fixing device 5, and is ejected by the automatic ejecting device 7.

Although a configuration example of a single-sided four-color printing machine has been shown here, the present invention is not limited to this, and the number of colors and single-sided / double-sided printing can be arbitrarily determined as the apparatus configuration. .

On the other hand, FIG. 7 and FIG. 8 are diagrams showing a schematic configuration example of a printing device for performing drawing by sandwiching a printing medium with a cap stun roller and running it according to the present invention, and FIG. FIG. 8 is a diagram showing a schematic configuration example of a printing device using a sheet-shaped recording medium, and FIG.

Here, description will be given with reference to an overall configuration diagram of an apparatus for performing one-sided four-color printing on the roll-shaped print medium shown in FIG. The print medium M is sandwiched by two pairs of cap stun rollers 10 and conveyed, and ink ejection drawing is performed using data divided and calculated by an image data calculation control unit (21 in FIG. 9) into an appropriate number of pixels and gradations. It is drawn by the device 3.
In the area where drawing is performed by the ink discharge drawing device 3,
In electrostatic field ejection, it is preferable to provide a grounding means 11 to serve as a counter electrode of the recording head electrode, which facilitates drawing.

Further, in FIG. 7, the sheet cutter 8 is provided upstream of the automatic ejecting device 7 for cutting the roll-shaped print medium, but the sheet cutter can be arranged at any suitable place.

Next, with reference to FIG. 7, the process of producing a printed matter by the printing apparatus of the present invention will be described in more detail below.

First, the print medium is conveyed by using the cap stun roller 10. At this time, if necessary, by providing a print medium guide unit (not shown), it is possible to prevent the head / butt of the print medium from flapping and coming into contact with and damaging the ink ejection drawing device 3. Further, means for preventing the print medium from slacking only around the drawing position of the ink ejection drawing device is provided, and at least when drawing is performed, this is made to act to prevent the print medium from contacting the ink ejection drawing device. You can also Specifically, for example, there is a method of arranging pressing rollers upstream and downstream of the drawing position. Furthermore, when drawing is not performed, it is desirable to keep the head away from the print medium, which can effectively prevent the occurrence of problems such as contact damage in the ink ejection drawing device.

Image data from the magnetic disk device, etc.
The image data calculation control unit 21 of FIG. 9 calculates the discharge position of the oil-based ink and the halftone dot area ratio at that position according to the input image data. These calculation data are temporarily stored in the buffer.
The image data calculation control unit 21 includes the inkjet head 2
2 is performed, the ejection timing of the oil-based ink is controlled, the operation timing of the cap stun roller is controlled, and the recording head 22 is brought closer to the position closer to the print medium by the head separating / contacting device 31 as necessary. The distance between the recording head 22 and the surface of the print medium is maintained at a predetermined distance during drawing by mechanical distance control such as a contact roller or control of the head contact / contact device by a signal from an optical distance detector. . Due to such distance control, good dot printing can be performed without making the dot diameter non-uniform due to floating of the printing medium or changing the dot diameter especially when vibration is applied to the printing apparatus.

A single-channel head, a multi-channel head, or a full-line head can be used as the recording head 22, and the sub-scanning is performed by transporting the print medium. In the case of a multi-channel head having a plurality of ejection parts, the ejection parts are arranged in a direction substantially parallel to the running direction of the print medium. Further, in the case of a single-channel head or a multi-channel head, the image data calculation control unit 21 moves the head 22 in the direction perpendicular to the running direction of the print medium, and the ejection position and halftone dot area ratio obtained by the above calculation are used. Ejects oil-based ink. As a result, on the print medium, a halftone image corresponding to the shade of the print original is drawn with the oil-based ink. This operation continues until the desired oil-based ink image is formed on the print medium. On the other hand, when the recording head 22 is a full line head having a length substantially the same as the width of the drum, the arrangement direction of the ejection units is set substantially perpendicular to the running direction of the print medium, and the print medium passes through the drawing unit. By doing so, an oil-based ink image is formed on the print medium. The printed printing medium is fixed by the fixing device 5, and is discharged by the automatic discharging device.

Although a configuration example of a single-sided four-color printing machine is shown here, the present invention is not limited to this, and the number of colors and single-sided / double-sided printing can be arbitrarily determined as necessary.

Next, the ink discharge drawing device 3 is shown in FIG.
Will be described in detail.

As shown in FIG. 9, the drawing apparatus used in this ink jet printing method comprises a recording head 22 and an ink supply unit 24. The ink supply unit 24 further includes
It has an ink tank 25, an ink supply device 26, and an ink concentration control means 29, and a stirring means 27 in the ink tank.
Ink temperature management means 28 is included. The ink may be circulated in the head, and in this case, the ink supply unit also has a recovery circulation function. The stirring means 27 is used to settle the solid components of the ink.
Suppress aggregation. As the stirring means, a rotary vane, an ultrasonic vibrator, and a circulation pump can be used, and these are used or in combination. Ink temperature management means 28
Is arranged so that a high-quality image can be stably formed without changing the physical properties of the ink due to a change in ambient temperature and changing the dot diameter. As the ink temperature control means, a heater, a Peltier element or other heating element or cooling element is arranged in the ink tank together with the stirring means so as to keep the temperature distribution in the tank constant, and is controlled by a temperature sensor such as a thermostat. A publicly known method such as a method of using can be used. The ink temperature in the ink tank is 15 ℃.
The temperature is preferably 60 ° C or lower and more preferably 20 ° C or higher and 50 ° C or lower. Further, the stirring means for keeping the temperature distribution in the tank constant may be shared with the stirring means for the purpose of suppressing precipitation / aggregation of the solid component of the ink. Further, the present drawing printing apparatus has the ink density control means 29 for performing high quality drawing. The ink density is measured by optical detection, measurement of electrical properties, measurement of physical properties such as viscosity, or control by the number of drawn images. When controlling by measuring physical properties, an optical detector, electric conductivity measuring instrument, viscosity measuring instrument are provided individually or in combination in the ink tank or ink flow path, and drawing is performed again by the output signal. In the case of management by the number of printed sheets, the liquid supply from the replenishing concentrated ink tank or the diluting ink carrier tank (not shown) to the ink tank is controlled depending on the number of printed sheets and the frequency.

As described above, the image data calculation control section 21 calculates the input image data, and the head separating / connecting device 31,
The timing pulse from the encoder 30 installed on the opposing drum or the cap stun roller is taken in, and the head is driven according to the timing pulse. Further, when drawing by the ink jet recording apparatus, the drawing drum is driven by using a highly accurate driving means. Specifically, for example, the output from the high-precision motor is the high-precision gear,
Alternatively, there is a method of driving the drawing drum by decelerating with a steel belt or the like. By using such means alone or in combination, it is possible to perform drawing with higher image quality.

Next, the recording head will be described with reference to FIGS.
To explain. However, the contents of the present invention are not limited to the following examples.

10 and 11 show an example of a head provided in the ink jet recording apparatus. Head 22
Has a slit sandwiched by an upper unit 221 and a lower unit 222 made of an insulating base material, the tip of which is a discharge slit 22a, and a discharge electrode 22b is arranged in the slit. The ink 23 supplied from the inside is in a state where the slit is filled.
Examples of the insulating base material include plastic, glass,
Ceramics can be applied. In addition, the ejection electrode 22b
Are vacuum-deposited, sputtered, or electroless plated with a conductive material such as aluminum, nickel, chromium, gold, or platinum on the lower unit 222 made of an insulating base material.
A photoresist is applied on this, the photoresist is exposed through a mask having a predetermined electrode pattern, and the photoresist is developed to form a photoresist pattern of the ejection electrode 22b, which is then etched or mechanically removed. It is formed by a known method such as a method or a combination thereof.

In the head 22, a voltage is applied to the ejection electrode 22b according to a digital signal of image pattern information. As shown in FIG. 10, a drawing drum serving as a counter electrode is installed so as to face the ejection electrode 22b, and a print medium is provided on the drawing drum. By applying a voltage, a circuit is formed between the ejection electrode 22b and the drawing drum serving as the counter electrode, and the oil ink 23 is ejected from the ejection slit 22a of the head 22 and provided on the drawing drum serving as the counter electrode. An image is formed on the print medium.

The width of the ejection electrode 22b is preferably as thin as possible in order to form a high quality image. The specific numerical value varies depending on the conditions such as the applied voltage and the physical properties of the ink, but it is usually used in the range of the tip width of 5 to 100 μm.

For example, the discharge electrode 22b having a tip having a width of 20 μm
The drawing drum 4 serving as the discharge electrode 22b and the counter electrode by using
With a distance of 1.0 mm and a voltage of 3 KV applied for 0.1 ms between the electrodes, 40 μm dots can be formed on the print medium 9.

Further, FIGS. 12 and 13 are respectively a schematic cross-sectional view and a schematic front view of the vicinity of the ink ejection portion of another example of the recording head. In the figure, 22 is a recording head,
The recording head 22 has a first insulating base material 33 having a tapered shape. The first insulating base material 33 has a second
The insulating base materials 34 are provided so as to face each other with a space therebetween, and a slope portion 35 is formed at the tip end portion of the second insulating base material 34. The first and second insulating base materials are made of, for example, plastic, glass, ceramics or the like. The upper surface portion 3 forming an acute angle with the inclined surface portion 35 of the second insulating base material 34.
In FIG. 6, a plurality of ejection electrodes 22b are provided as electrostatic field forming means for forming an electrostatic field in the ejection portion. The tip of each of the plurality of ejection electrodes 22b extends to the vicinity of the tip of the upper surface portion 36, and the tip is protruded in front of the first insulating base material 33 to form an ejection portion.
Between the first and second insulating base materials 33 and 34, the ink inflow path 3 is provided as a means for supplying the ink 23 to the ejection portion.
7 is formed, and an ink recovery path 38 is formed on the lower side of the second insulating base material 34. The discharge electrode 22
b is formed on the second insulating base material 34 by a known method using a conductive material such as aluminum, nickel, chromium, gold, or platinum, similarly to the above. Individual electrodes 22b
Are electrically insulated from each other. The amount of the tip of the ejection electrode 22b protruding from the tip of the insulating base material 33 is preferably 2 mm or less. The reason why the amount of protrusion is limited to the above range is that if the amount of protrusion is too large, the ink meniscus does not reach the tip of the ejection portion, ejection becomes difficult, and the recording frequency decreases. Also,
The space between the first and second insulating base materials 33 and 34 is preferably in the range of 0.1 to 3 mm. The reason for limiting this space to the above range is that if the space is too narrow, it becomes difficult to supply the ink and ejection becomes difficult, or the recording frequency is lowered, and if the space is too wide, the meniscus is not stable. This is because the ejection becomes unstable.
The ejection electrode 22b is connected to the image data calculation control unit 21, and when recording, a voltage is applied to the ejection electrode based on image information to eject ink on the ejection electrode, and the ejection electrode 22b is arranged opposite to the ejection unit. Drawing is performed on a print medium (not shown). The direction opposite to the ink droplet ejection direction of the ink inflow path 37 is connected to an ink feeding means of an ink supply device (not shown). A backing 39 is provided on the surface of the second insulating base material 34 opposite to the surface on which the ejection electrodes are formed so as to face each other, and an ink recovery path 38 is provided between the two. The space of the ink recovery path 38 is preferably 0.1 mm or more. The reason for limiting the space to the above range is that if the space is too narrow, it will be difficult to collect the ink and ink will leak. The ink recovery passage 38 is connected to an ink recovery means (not shown) of an ink supply device. If a uniform ink flow on the ejection portion is required, a groove 40 may be provided between the ejection portion and the ink recovery passage. Although FIG. 13 shows a schematic front view of the vicinity of the ink ejection portion of the recording head, a plurality of grooves are formed on the slope of the second insulating substrate 34 from the vicinity of the boundary with the ejection electrode 22b toward the ink recovery passage 38. 40 is provided. A plurality of the grooves 40 are arranged in the arrangement direction of the ejection electrodes 22b, and a certain amount of ink near the tip of the ejection electrodes is guided from the opening on the ejection electrode 22b side by a capillary force corresponding to the opening diameter. Ink recovery path 3
8 has the function of discharging. Therefore, it has a function of forming an ink flow having a constant liquid thickness near the tip of the ejection electrode. The shape of the groove 40 may be in the range in which the capillary force works, but particularly preferably, the width is 10 to 200 μm and the depth is 10 to 300 μm. Further, the grooves 40 are provided in the required number so that a uniform ink flow can be formed over the entire surface of the head.

The width of the ejection electrode 22b is preferably as thin as possible in order to form a high quality image. Although the specific numerical value varies depending on the applied voltage, the physical properties of the ink, etc., it is usually used in the range of the tip width of 5 to 100 μm.

Further, another example of the recording head used for carrying out the present invention is shown in FIGS. 14
FIG. 4 is a schematic view showing only a part of the head for explanation. As shown in FIG. 14, the recording head 22 is composed of a head body 41 made of an insulating material such as plastic, ceramic, glass, etc. and meniscus regulating plates 42, 42 '. In the figure, 22b is an ejection electrode for applying a voltage to form an electrostatic field in the ejection portion. Further, the head body will be described in detail with reference to FIG. 15 in which the regulation plates 42 and 42 'are removed from the head. The head body 41 is provided with a plurality of ink grooves 43 for circulating ink perpendicularly to the edge of the head body. The shape of the ink groove 43 may be set in a range in which a capillary force works so that a uniform ink flow can be formed, but the width is particularly preferably 10 to 200 μm.
m, and the depth is 10 to 300 μm. A discharge electrode 22b is provided inside the ink groove 43. The ejection electrode 22b is formed by using a conductive material such as aluminum, nickel, chromium, gold, or platinum on the head body 40 made of an insulating material by a known method similar to the case of the above-described apparatus embodiment. It may be arranged on the entire surface of the groove 43 or may be formed on only a part thereof. The ejection electrodes are electrically isolated. Two adjacent ink grooves form one cell, and ejection portions 45 and 45 'are provided at the tip of the partition wall 44 at the center thereof. In the ejection portions 45 and 45 ', the partition walls are thinner than the other partition wall portions 44 and are sharpened. Such a head body is formed by a known method such as machining an insulating material block, etching, or molding. The thickness of the partition wall at the ejection portion is preferably 5 to 100 μm, and the radius of curvature of the sharpened tip is preferably in the range of 5 to 50 μm. The discharge portion may have a slightly chamfered end like 45 '. Although only two cells are shown in the figure,
The cells are partitioned by a partition wall 46, and the tip end portion 47 thereof is chamfered so as to be retracted from the discharge portions 45 and 45 '. To this head, ink is supplied from an ink supply device (not shown) through an ink groove from the direction I to supply the ink to the ejection portion. Further, the excess ink is recovered in the O direction by an ink recovery means (not shown), and as a result, fresh ink is constantly supplied to the ejection portion. In this state, a voltage is applied to the discharge electrode according to the image information to a drawing drum (counter drum) (not shown), which is provided so as to face the discharge unit and the print medium is in contact with the surface of the discharge medium. Ink is ejected from the portion to form an image on the print medium.

Further, another embodiment of the recording head will be described with reference to FIG. As shown in FIG. 16, the recording head 22 has a pair of substantially rectangular plate-shaped supporting members 50 and 50 '. These supporting members 50, 50 'are made of an insulating plate-like plastic having a thickness of 1 to 10 mm, glass, ceramics, etc., and one surface of each of them is parallel to each other depending on the recording resolution. A plurality of elongated rectangular grooves 51, 51 'are formed. Each groove 51, 5
1'is preferably in the range of 10 to 200 μm in width and 10 to 300 μm in depth, and the ejection electrode 22b is formed in the whole or a part thereof. By thus forming the plurality of grooves 51, 51 'on one surface of the support member 50, 50', a plurality of rectangular partition walls 52 are necessarily provided between the grooves 51. Each support member 50, 50 '
Are combined so that the surfaces not forming the grooves 51, 51 'face each other. That is, the recording head 22 has a plurality of grooves on the outer peripheral surface for circulating the ink.
Grooves 51, 51 'formed in each support member 50, 50'
Are connected in a one-to-one correspondence via the rectangular portions 54 of the recording head 22, and the rectangular portions 54 to which the respective grooves are connected are separated from the upper end 53 of the recording head 22 by a predetermined distance (50 to 500 μm).
m) has retreated. That is, on both sides of each rectangular portion 54, the upper end 55 of each partition wall 52 of each support member 50, 50 'is provided.
Are provided so as to project from the rectangular portion 54. Then, the guide projections 56 made of an insulating material as described above are provided so as to project from each rectangular portion 54 to form a discharge portion. Recording head 22 configured as described above
When the ink is circulated through the ink, the ink is supplied to each rectangular portion 54 through each groove 51 formed on the outer peripheral surface of the one support member 50, and each groove 51 ′ formed on the opposite support member 50 ′. Discharge through. In this case, the recording head 22 is inclined at a predetermined angle in order to enable smooth ink circulation. That is, the ink supply side (support member 50)
Is located above and the recording head 22 is inclined so that the ink discharge side (support member 50 ') is located below. As described above, when the ink is circulated in the recording head 22, the ink passing through the rectangular portions 54 gets wet along the protrusions 56, and an ink meniscus is formed near the rectangular portions 54 and the protrusions 56. Then, in the state where the ink meniscus is formed independently in each rectangular portion 54, the ejection electrode 22b is provided to the drawing drum (not shown) which is provided so as to face the ejection portion, and the surface of which is in contact with the print medium. By applying a voltage based on the image information,
Ink is ejected from the ejection unit to form an image on the print medium. By providing a cover for covering the groove on the outer peripheral surface of each of the support members 50, 50 ', each of the support members 50, 5'
A pipe-shaped ink flow path is formed along the outer peripheral surface of 0 ',
Ink may be forcibly circulated by this ink flow path. In this case, it is not necessary to tilt the recording head 22.

The recording head 22 described above with reference to FIGS.
In order to maintain a good drawing state, cleaning or the like is performed. For example, in the case where the pause state continues or when a problem occurs in the image quality, the tip of the recording head is wiped with a flexible brush, brush, cloth, etc., only the ink solvent is circulated, or only the ink solvent is supplied or Suction the ejection part while circulating, and to prevent ink sticking, keep the recording head inside a cover filled with ink solvent vapor, cool the head part to suppress evaporation of ink solvent, and further stain In severe cases, ink is forcibly sucked from the ejection part, air, ink or a jet of ink solvent is forced from the ink flow path, or ultrasonic waves are applied while the head is immersed in the ink solvent. These methods are used alone or in combination.

Next, the print medium used in the present invention will be described. Examples of print media include high-quality paper, finely coated paper, and coated paper, which are commonly used printing papers.
Further, for example, a polyolefin laminated paper having a resin film layer on the surface, and a plastic film such as a polyester film, a polystyrene film, a vinyl chloride film, a polyolefin film, or the like can also be used. Further, a plastic film or processed paper having a surface on which metal is vapor-deposited or a metal foil is laminated can be used. Of course, dedicated paper and film for inkjet can also be used.

The oil-based ink used in the present invention will be described below.

The oil-based ink used in the present invention comprises at least colored particles dispersed in a non-aqueous solvent having a specific electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less.

Specific electric resistance used in the present invention 10 ⁹ Ωcm
As a non-aqueous solvent having a dielectric constant of 3.5 or less, a linear or branched aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon, and halogen-substituted products of these hydrocarbons are preferable. is there. For example, hexane, heptane, octane, isooctane, decane, isodecane, decalin,
Nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper C, isoper E, isoper G, isoper H, isoper L (Isoper; trade name of Exxon company), Shersol 70, shell Zol 71 (Shellsol; trade name of Shell Oil Co., Ltd.), Amsco OMS, Amsco 460 solvent (Amsco; trade name of Spirits Co. Ltd.), silicone oil and the like are used alone or in combination. The upper limit of the specific electric resistance of such a non-aqueous solvent is about 10 ¹⁶ Ωcm, and the lower limit of the dielectric constant is about 1.9.

The electric resistance of the non-aqueous solvent used is within the above range. When the electric resistance is low, concentration of colored particles or the like is less likely to occur, and the color of the formed dod becomes light or bleeding occurs. The reason why the dielectric constant is in the above range is that as the dielectric constant increases, the electric field is relaxed due to the polarization of the solvent, which tends to deteriorate the ejection of ink.

The colored particles dispersed in the above non-aqueous solvent may be the coloring material itself dispersed as dispersed particles in the non-aqueous solvent, or may be contained in the dispersed resin particles for improving the fixing property. You may let me. When it is contained, a pigment or the like is generally coated with a resin material of dispersed resin particles to obtain resin-coated particles, and a dye or the like is generally pigmented by dispersing resin particles into colored particles. is there.

As the coloring material, any pigment and dye conventionally used in oil-based ink compositions or liquid developers for electrostatic photography can be used.

As the pigment, regardless of whether it is an inorganic pigment or an organic pigment, those generally used in the technical field of printing can be used. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, viridian, cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment. , Quinacridone pigments, isoindolinone pigments, dioxazine pigments, slene pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments, etc. Can be used without.

As the dye, azo dye, metal complex salt dye,
Naphthol dye, anthraquinone dye, indigo dye,
Oil-soluble dyes such as carbonium dyes, quinone imine dyes, xanthene dyes, aniline dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, phthalocyanine dyes and metal phthalocyanine dyes are preferable.

These pigments and dyes may be used alone or in an appropriate combination, but they are contained in the range of 0.5 to 5% by weight based on the whole ink. desirable.

The oil-based ink used in the present invention preferably contains dispersed resin particles for improving the fixability of an image after printing, in addition to the above-mentioned colored particles.

The resin particles to be dispersed in the above non-aqueous solvent may be particles of a hydrophobic resin which are solid at a temperature of 35 ° C. or lower and have good affinity with the non-aqueous solvent. Glass transition point is -5 ° C to 110 ° C or softening point is 33 ° C
The resin (P) having a temperature of ˜140 ° C. is preferable, and more preferably, the glass transition point is 10 ° C. to 100 ° C. or the softening point is 38 ° C. to 1.
20 ° C., more preferably glass transition point 15 ° C.
The softening point is 80 ° C or 38 ° C to 100 ° C.

By using such a resin having a glass transition point or a softening point, the affinity between the surface of the print medium and the resin particles is increased, and the resin particles are strongly bonded to each other on the print medium. The adhesion between the image area and the surface of the printing medium is improved, and the abrasion resistance is improved. On the other hand, if the glass transition point or the softening point is low or high, the affinity between the surface of the print medium and the resin particles is lowered, or the bond between the resin particles is weakened.

The weight average molecular weight Mw of the resin (P) is 1 ×
10 ³ to 1 × 10 ⁶ , preferably 5 × 10 ³ to 8 ×
10 ⁵ and more preferably 1 × 10 ^{4 to} 5 × 10 ⁵ .

Specifically as such a resin (P),
Olefin polymers and copolymers (eg polyethylene,
Polypropylene, polyisobutylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer, ethylene-methacrylic acid copolymer, etc.), vinyl chloride polymer and copolymer (for example, polychlorinated Vinyl, vinyl chloride-vinyl acetate copolymer, etc.), vinylidene chloride copolymer, vinyl alkanoate polymer and copolymer, allyl alkanoate polymer and copolymer, polymer and copolymer of styrene and its derivatives (For example, butadiene-styrene copolymer, isoprene-
Styrene copolymer, styrene-methacrylate copolymer, styrene-acrylate copolymer, etc.), acrylonitrile copolymer, methacrylonitrile copolymer, alkyl vinyl ether copolymer, acrylic acid ester polymer and copolymer, methacryl Acid ester polymer and copolymer, itaconic acid diester polymer and copolymer, maleic anhydride copolymer, acrylamide copolymer, methacrylamide copolymer, phenol resin, alkyd resin, polycarbonate resin, ketone resin, polyester resin,
Silicone resin, amide resin, hydroxyl group and carboxyl group modified polyester resin, butyral resin, polyvinyl acetal resin, urethane resin, rosin resin, hydrogenated rosin resin, petroleum resin, hydrogenated petroleum resin, maleic acid resin, terpene resin, hydrogenated resin Terpene resin, coumarone-indene resin, cyclized rubber-methacrylic acid ester copolymer, cyclized rubber-acrylic acid ester copolymer, copolymer containing a nitrogen atom-free heterocycle (for example, as a heterocycle, furan Ring, tetrahydrofuran ring, thiophene ring, dioxane ring, dioxofuran ring, lactone ring,
Benzofuran ring, benzothiophene ring, 1,3-dioxetane ring and the like), epoxy resin and the like.

The total content of the dispersed colored particles and resin particles in the oil-based ink of the present invention is preferably 0.5 to 20% by weight of the total ink. When the content is low, the density of the printed image is insufficient, and the affinity between the ink and the surface of the printing medium is difficult to be obtained, which makes it difficult to obtain a strong image. When the amount is large, it is difficult to obtain a uniform dispersion liquid, and the ink flow in the recording head is likely to be non-uniform, which makes it difficult to obtain stable ink ejection.

The average particle size of these particles including the colored particles dispersed in the non-aqueous solvent of the present invention and further the resin particles and the like is preferably 0.05 to 5 μm. It is more preferably 0.1 μm to 1.5 μm, and even more preferably 0.4.
It is in the range of μm to 1.0 μm. This particle size is CAPA-
500 (trade name, manufactured by HORIBA, Ltd.).

The non-aqueous dispersion colored particles used in the present invention can be produced by a conventionally known mechanical grinding method or polymerization granulation method. As a mechanical pulverizing method, if necessary, a colorant and a resin are mixed, melted and kneaded, and then directly pulverized by a conventionally known pulverizer to obtain fine particles, and a dispersion polymer is used in combination, and a wet disperser is further used. (For example, ball mill
Dispersion with a paint shaker, Keddy mill, Dynomill, etc.), a colorant material to be a colored particle component and a dispersion-aiding polymer (or coating polymer) are previously kneaded to form a kneaded product, which is then pulverized, and then the dispersion polymer coexists. And the like. Specifically, a method for producing a paint or a liquid developer for electrostatic photography can be used. For these, for example, "Flow of paint and pigment dispersion" translated by Kenji Ueki, Kyoritsu Shuppan (1971), Solomon ". Paint Science "
Hirokawa Shoten (1969), Yuji Harasaki "Coating Engineering"
Asakura Shoten (1971), Yuji Harazaki "Basic Science of Coating" Maki Shoten (1977) and other books.

There is also a method of producing colored particles by coloring resin particles granulated by the polymerization granulation method by dyeing.
As the polymerization granulation method, a conventionally known non-aqueous dispersion polymerization method can be mentioned, and specifically, “Latest Technology of Ultrafine Particle Polymer” by Soichi Muroi, Chapter 2, CMC Publishing (1991), edited by Koichi Nakamura. "Development and Practical Use of Recent Electrophotographic Development Systems and Toner Materials" Chapter 3, (Japan Science Information Co., Ltd., 1985), KEJ Barrett "Dispersion Polymerization"
in Organic Media ”John Wiley (1975) and other books.

Usually, a dispersing polymer is used together to stabilize the dispersed particles in a non-aqueous solvent. The dispersion polymer contains a repeating unit soluble in a non-aqueous solvent as a main component, and has an average molecular weight of 1 × 10 5 as a weight average molecular weight Mw.
³ to 1 × 10 ⁶ is preferable, and more preferably 5 × 10 ³
The range is from 5 × 10 ⁵ .

A preferred soluble repeating unit of the dispersion polymer used in the present invention is a polymerization component represented by the following general formula (1).

[0077]

[Chemical 1]

In the general formula (I), X ₁ is --COO.
Represents-, -OCO- or -O-.

R represents an alkyl group or alkenyl group having 10 to 32 carbon atoms, preferably an alkyl group or alkenyl group having 10 to 22 carbon atoms, which may be linear or branched and is unsubstituted. However, it may have a substituent.

Specifically, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, decenyl group,
Examples thereof include a dodecenyl group, a tridecenyl group, a hexadecenyl group, an octadecenyl group, and a linolenyl group.

A ₁ and a ₂ may be the same as or different from each other, and are a hydrogen atom, a halogen atom (eg, chlorine atom, bromine atom, etc.), a cyano group, an alkyl group having 1 to 3 carbon atoms (eg, methyl group). Group, ethyl group, propyl group, etc.),
-COO-Z ₁ or -CH ₂ COO-Z ₁ [Z ₁ is
Represents an optionally substituted hydrocarbon group having 22 or less carbon atoms (for example, an alkyl group, an alkenyl group, an aralkyl group, an alicyclic group, an aryl group, etc.).

Among the hydrocarbon groups represented by Z ₁ , preferred hydrocarbon groups include an optionally substituted alkyl group having 1 to 22 carbon atoms (eg, methyl group, ethyl group, propyl group, butyl group, Hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group,
Tetradecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, 2-chloroethyl group, 2
-Bromoethyl group, 2-cyanoethyl group, 2-methoxycarbonylethyl group, 2-methoxyethyl group, 3-bromopropyl group, etc.), an alkenyl group having 4 to 18 carbon atoms which may be substituted (for example, 2-methyl- 1-propenyl group, 2-butenyl group, 2-pentenyl group, 3-methyl-
2-pentenyl group, 1-pentenyl group, 1-hexenyl group, 2-hexenyl group, 4-methyl-2-hexenyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, linolenyl group, etc.),
Aralkyl groups having 7 to 12 carbon atoms which may be substituted (eg, benzyl group, phenethyl group, 3-phenylpropyl group, naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, An ethylbenzyl group, a methoxybenzyl group, a dimethylbenzyl group, a dimethoxybenzyl group, etc.), an alicyclic group having 5 to 8 carbon atoms which may be substituted (eg, a cyclohexyl group, 2
-Cyclohexylethyl group, 2-cyclopentylethyl group, etc.) and optionally substituted aromatic group having 6 to 12 carbon atoms (eg, phenyl group, naphthyl group, tolyl group, xylyl group, propylphenyl group, butylphenyl group) , Octylphenyl group, dodecylphenyl group, methoxyphenyl group, ethoxyphenyl group, butoxyphenyl group, decyloxyphenyl group, chlorophenyl group, dichlorophenyl group, bromophenyl group, cyanophenyl group, acetylphenyl group, methoxycarbonylphenyl group, ethoxy Carbonylphenyl group, butoxycarbonylphenyl group, acetamidophenyl group, propionamidophenyl group, dodecyloylamidophenyl group, etc.).

In addition to the repeating unit represented by formula (I), the dispersing polymer may contain another repeating unit as a copolymerization component. Other copolymerization components include
Any compound may be used as long as it is composed of a monomer copolymerizable with the monomer corresponding to the repeating unit of the general formula (I).

The content of the polymer component represented by formula (I) in the dispersion polymer is preferably 50% by weight or more, more preferably 60% by weight or more.

Specific examples of these dispersion polymers include:
Examples include the dispersion stabilizing resin (Q-1) used in the examples, and a commercially available product (Sorprene 1205, manufactured by Asahi Kasei Co., Ltd.) can also be used.

The dispersion polymer is preferably added in advance during the polymerization when the resin (P) particles are produced as a dispersion (latex) or the like.

The amount of the dispersed polymer added is the resin (P) for particles.
To about 1 to 50% by weight.

The colored particles (or coloring material particles) and the dispersed resin particles in the oil-based ink of the present invention are preferably positively or negatively charged electroscopic particles.

In order to impart an electroscopic property to these particles, it is possible to appropriately use the technique of a developer for wet electrostatic photography. Specifically, the above-mentioned "Recent Electrophotographic Development System and Toner Material Development and Practical Use", pp. 139-148,
The Electrophotographic Society, "Basics and Applications of Electrophotographic Technology", 497-
505 (Corona Publishing Co., Ltd., 1988), Yuji Harazaki “Electronic Photography” 16 (No. 2), 44 (1977), etc., by using a charge-detecting material such as a charge detection agent and other additives. Done.

Specifically, for example, British Patent No. 8934.
No. 29, No. 934038, No. 1122397,
U.S. Pat. Nos. 3,900,412 and 4,606,989,
JP-A-60-179751, JP-A-60-185963
And Japanese Patent Laid-Open No. 13965/1990.

The above charge control agent is preferably 0.001 to 1.0 part by weight with respect to 1000 parts by weight of a dispersion medium which is a carrier liquid. If desired, various additives may be added, and the upper limit of the total amount of these additives is restricted by the electric resistance of the oil-based ink. That is, if the specific electric resistance of the ink with the dispersed particles removed is lower than 10 ⁹ Ωcm, it becomes difficult to obtain a good quality continuous tone image. Therefore, it is possible to control the addition amount of each additive within this range. desirable.

[0092]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. First, a production example of the resin particles for ink (PL-1) will be described.

Production Example 1 Production of Resin Particles (PL-1) 10 g of a dispersion stabilizing resin (Q-1) having the following structure, 100 g of vinyl acetate and 384 g of Isopar H were added to a temperature of 70 ° C. while stirring under a nitrogen stream. Warmed. 0.8 g of 2,2'-azobis (isovaleronitrile) (abbreviation AIVN) was added as a polymerization initiator, and the reaction was carried out for 3 hours. Twenty minutes after the addition of the initiator, white turbidity occurred and the reaction temperature rose to 88 ° C. Further, 0.5 g of this initiator was added and after reacting for 2 hours, the temperature was raised to 100 ° C. and stirred for 2 hours to distill off unreacted vinyl acetate. After cooling, it was passed through a nylon cloth of 200 mesh, and the obtained white dispersion was a latex having a polymerization rate of 90% and an average particle size of 0.23 μm and good monodispersity. The particle size was measured by CAPA-500 (manufactured by Horiba, Ltd.).

[0094]

[Chemical 2]

A part of the white dispersion was subjected to a centrifuge (rotation speed 1 × 10 ⁴ rpm, rotation time 60 minutes) to collect and dry the precipitated resin particle component. The weight average molecular weight of the resin particles (Mw: polystyrene-converted GPC value) is 2
× 10 ⁵ , glass transition point (Tg) was 38 ℃.

Next, an oil-based ink was prepared. <Oil-based ink (IK-1)> Dodecyl methacrylate /
Acrylic acid copolymer (copolymerization ratio; 95/5 weight ratio) 1
0g, Nigrosine 10g and Shersol 71 30g
Was placed in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) together with glass beads and dispersed for 4 hours to obtain a fine dispersion of nigrosine.

30 g of resin particles (PL-1) of Production Example 1 of resin particles for ink (as solid content), 20 g of the above nigrosine dispersion, FOC-1400 (Nissan Chemical Co., Ltd.).
(Trade name, tetradecyl alcohol) 15 g, and octadecene-half-maleic acid octadecylamide copolymer 0.08
A black oil-based ink was prepared by diluting g to 1 liter of Isopar G.

Next, an ink tank was filled with 2 liters of the oil-based ink (IK-1) prepared as described above in the ink jet recording apparatus of the drawing apparatus of the printing apparatus shown in FIG.
Here, the recording head 900 of the type shown in FIG. 12 is used.
A dpi, full line head was used. As an ink temperature control means, a throw-in heater and a stirring blade are provided in the ink tank, the ink temperature is set to 30 ° C., and the stirring blade is 30 rp.
The temperature was controlled with a thermostat while rotating at m. Here, the stirring blade was also used as a stirring means for preventing sedimentation and aggregation. In addition, a part of the ink flow path is made transparent, an LED light emitting element and a light detecting element are arranged with the ink flow path sandwiched therebetween, and an output signal from the LED diluting solution (isopar G) or concentrated ink (solid content of the above IK-1 ink). The concentration was controlled by adding the one whose concentration was adjusted to double. A roll-shaped slightly coated paper as a print medium was provided on the opposing drum and conveyed. After removing dust on the surface of the print medium with the adhesive roller, bring the recording head close to the print medium to the drawing position,
The image data to be printed was transmitted to the image data operation control unit, and the oil-based ink was ejected from the full-line multi-channel head while the printing medium was conveyed by the rotation of the opposed drum to form an image. At this time, the tip width of the ejection electrode of the inkjet head was 10 μm, and the distance between the head and the print medium was 1 m according to the output from the optical gap detection device.
kept m. A voltage of 2.5 kV is always applied as a bias voltage, a pulse voltage of 500 V is further superimposed when performing ejection, and the pulse voltage is 256 steps in the range of 0.2 ms to 0.05 ms. Drawing was performed while changing the area of the dots by changing with. On this occasion,
The adhesive force of the adhesive roller is 7 hPa or more and 180 hPa or less (Example 1), 4 hPa or more and 7 hPa or less (Example 2), 180 hPa or more and 250 hPa or less (Example 3), 4 hPa or less (Comparative Example 1), 250 hPa or more (Comparative Example 2) ). As a result, in Example 1, most of the dust adhering to the print medium can be adsorbed and removed by the adhesive roller, troubles such as clogging of the recording head do not occur, and clear images without defects such as damage to the print medium can be obtained. I was able to. Further, in Example 2, although dust was slightly left on the print medium, there was no problem. Furthermore,
In the third embodiment, depending on the printing conditions, although it is slight,
Although wrinkles were seen on the print medium, it was at a level where there was no problem in practical use. Further, even when the outside air temperature changed and the printing time increased, the image deterioration due to the change of the dot diameter was not observed at all, and good printing was possible. On the other hand, in Comparative Example 1, the dust adsorption capacity was small and it was impossible to remove the dust. Further, in Comparative Example 2, the suction force between the adhesive roller and the print medium was strong, and there were some wrinkles and breaks in the print medium.

Further, the image was strengthened by heating with a xenon flash fixing device (manufactured by USHIO INC., Emission intensity 200 J / pulse). After the printing was completed, the inkjet recording device was retracted by 50 mm from the position close to the drawing drum in order to protect the inkjet head.

The printed matter obtained was an extremely clear image with no jumps or scratches on the printed image. After printing, the tip of the recording head is dipped in Isopar G and 1 kV
By applying a positive DC voltage of 30 seconds for 30 seconds, good printed matter could be produced for 3 months without requiring maintenance work.

[0101]

According to the present invention, in a printing method in which an image is directly formed on a print medium and the image is fixed to form a printed matter, before and / or during the formation of the image on the print medium. , The adhesive roller is rolled on the print medium to adsorb and remove the dust on the print medium.
It is possible to prevent failure due to dust on the print medium adhering to the ejection head, keep the recording head clean at all times, and print a large number of clear printed matter. Also,
It is possible to prevent image defects caused by the ink adhering to the dust on the print medium. As a result, it is possible to always print a printed matter of a clear and high-quality image with an inexpensive device and a simple method.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram schematically showing a Web-type apparatus that performs single-sided single-color printing, which is an example of an inkjet printing apparatus of the present invention.

FIG. 2 is an overall configuration diagram schematically showing a Web-based apparatus that is another example of the inkjet printing apparatus of the present invention and that prints four colors on one side.

FIG. 3 is an overall configuration diagram schematically showing a double-sided four-color printing apparatus which is another example of the inkjet printing apparatus of the present invention.

FIG. 4 is an overall configuration diagram schematically showing a double-sided four-color printing device which is another example of the inkjet printing device of the present invention.

FIG. 5 is an overall configuration diagram schematically showing a single-sided four-color printing device that is another example of the inkjet printing device of the present invention, in which a roll-shaped printing medium is cut and wound around an opposed drum to perform printing.

FIG. 6 is an overall configuration diagram schematically showing a printing apparatus using a sheet-shaped recording medium, which is another example of the inkjet printing apparatus of the present invention.

FIG. 7 is an overall configuration diagram schematically showing another example of the ink jet printing apparatus of the present invention, which is a printing apparatus that draws by drawing a roll printing medium while it is held by a cap stun roller and running.

FIG. 8 is an overall configuration diagram schematically showing another example of the inkjet printing apparatus according to the present invention, which is a printing apparatus that draws images by sandwiching a sheet-shaped recording medium with a cap stun roller and running the sheet-shaped recording medium.

FIG. 9 is a schematic configuration example of a drawing device including a control unit, an ink supply unit, and a head separation / contact mechanism of the drawing device of the inkjet printing apparatus of the present invention.

10 is a diagram illustrating an inkjet recording device included in the drawing device in FIG.

11 is a diagram for explaining an enlarged cross section of the inkjet recording apparatus of FIG.

FIG. 12 is a diagram showing a schematic cross-section in the vicinity of an ink ejection portion of another example of the recording head.

FIG. 13 is a diagram showing a schematic front view of the vicinity of an ink ejection portion of another example of the recording head.

FIG. 14 is a schematic view showing only a part of a recording head of another example.

FIG. 15 is a view showing the recording head of FIG.
It is the schematic diagram which removed.

FIG. 16 is a schematic view showing another embodiment of the recording head.

[Explanation of symbols]

1 Print media supply roll 2 Adhesive roller 3 Ink ejection drawing device 4 Opposing (drawing) drum 5 Fixing device 6 Print media take-up roll 7 Automatic discharging device 8 cutter 9 Automatic feeder 10 Cap Stan roller 11 Grounding means 20 Inkjet recording device 21 Image data calculation controller 22 recording head 221 Upper unit 222 Lower unit 22a discharge slit 22b Discharge electrode 23 Oil-based ink 24 Ink supply section 25 ink tanks 26 Ink supply device 27 stirring means 28 Ink temperature control means 29 Ink temperature control means 30 encoder 31 Head contact / separation device 32 head sub-scanning means 33 First Insulating Base Material 34 Second insulating base material 35 Slope of second insulating base material 36 Upper surface of second insulating base material 37 Ink flow path 38 Ink collection path 39 backing 40 grooves 41 head body 42, 42 'meniscus control plate 43 ink groove 44 partition 45, 45 'discharge part 46 partitions 47 Partition tip 48, 50 'support member 49, 51 groove 50 partitions 51 upper end 52 rectangle 53 Top of partition 54 Guide protrusion M print media

Claims (5)

[Claims] 1. An ink jet printing method in which an image is formed directly on a print medium by an ink jet method in which an oil-based ink is ejected by utilizing an electrostatic field based on a signal of image data, and the image is fixed to produce a printed matter. Ink jet printing, characterized in that, before and / or during the formation of an image on the print medium, an adhesive roller is rolled on the print medium to adsorb and remove dust on the print medium. Method. 2. The inkjet printing method according to claim 1, wherein the adhesive force of the adhesive roller is 4 hPa or more and 250 hPa or less. 3. An image forming means for directly forming an image on a print medium based on a signal of image data, and an image fixing means for fixing the image formed by the image forming means to obtain a printed matter. In a printing apparatus, which is an inkjet drawing apparatus in which the image forming unit uses an electrostatic field to eject an oil-based ink from a recording head, dust on a print medium is adsorbed and removed on an upstream side of a printing medium moving direction of the inkjet drawing apparatus. An ink jet printing apparatus, wherein an adhesive roller is arranged so as to be rollable on a print medium. 4. The printing apparatus according to claim 3, wherein the adhesive force of the adhesive roller is 4 hPa or more and 250 hPa or less. 5. The pressure-sensitive adhesive roller is composed of two or more pressure-sensitive adhesive rollers having different pressure-sensitive adhesive forces, one pressure-sensitive adhesive roller is rolled on a print medium, and pressure-sensitive adhesive force higher than that of the pressure-sensitive adhesive roller is used. The printing apparatus according to claim 4, wherein another adhesive roller having a sheet is brought into contact with the one adhesive roller.