JP2002059550A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recorder superior in image-weatherability and in versatility of paper wherein a life of a print head is long and a line head can be realized at low cost. SOLUTION: There is disclosed the image recorder that performs recording of an image, by ejecting from a nozzle, a liquid drop wherein a pigment colorant is dispersed into an insulative electric viscous fluid in response to a recording signal. The image recorder comprises at least one stirring member for dispersing and charging the pigment colorant and a print head capable of applying an electric field for controlling a supplying quantity of the colorant to a portion in the vicinity of the nozzle. The colorant is selectively ejected from the nozzle by an electric charge generating means corresponding to the print head, thereby recording the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image recording apparatus for recording an image by discharging a recording agent dispersed in an electrorheological fluid in response to an electric signal applied to a recording head.

[0002]

2. Description of the Related Art Conventionally, an ink jet printer which uses this kind of electrorheological fluid as ink and performs printing by electrically controlling the viscosity of the ink has been disclosed in Japanese Patent Laid-Open No. 2-1727.
No. 46, JP-A-6-246908 and JP-A-7-164641, etc., have already been proposed. These ink jet printers include a means for pressurizing the ink in the nozzle in the print head, a pair of electrodes facing each other at the nozzle tip, and applying a voltage between the electrodes to reduce the viscosity of the ink therebetween. Increasing the voltage suppresses the amount of ejected ink, and weakening this voltage increases the amount of ejected ink to perform printing.

[0003] To explain further, Japanese Patent Laid-Open Publication No.
The image forming method according to No. 46 discloses an image forming method in which droplets of a recording medium are ejected and fly from an orifice in accordance with a recording signal to form an image. An electro-rheological fluid that is dissolved, has an energy source for discharging at least one orifice of a recording material equal to or less than the number of orifices, and applies an electric field near the orifice. is there.

Further, the ink jet printer disclosed in Japanese Patent Application Laid-Open No. 6-246908 uses an electrorheological fluid as ink and heats the ink in an ink jet printer having electrodes for applying a voltage to the ink in the nozzles. Is provided near the electrode.

[0005] Further, the ink jet printer according to the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-164641 has an ink whose viscosity changes by an applied electric field, a nozzle body provided with a plurality of nozzles for accommodating the ink, An electrode provided inside each of the nozzles and applying an electric field to the ink in the nozzle, a pressure generating unit connected to each of the nozzles, and a driving source provided in the pressure generating unit, are provided by the driving source. In a state where pressure is applied to the ink in the nozzle, the viscosity of the ink is controlled by an electric field applied to the electrode.

[0006]

However, the prior art described above has the following problems. That is, Japanese Unexamined Patent Publication No. Hei.
In the case of the ink jet printer according to JP-A-246908 and JP-A-7-164641, the ejection means for ejecting ink as a recording body is a conventional Kaiser type, that is, a recording apparatus having an orifice for ejecting a recording body. An electric recording signal is applied to the piezoelectric vibrator attached to the head, the electric recording signal of the child is changed into mechanical vibration of the piezoelectric vibrator, and the droplet of the recording medium is discharged from the orifice according to the mechanical vibration. A method of performing recording by ejecting and flying and attaching to a recording member, a bubble jet (registered trademark)
A mold, that is, a system in which bubbles are generated by heating ink that is a recording medium, and droplets of the recording medium are ejected and fly by the pressure and adhere to a recording member to perform recording. Therefore, it is difficult to use a pigment-based coloring material in terms of uniformity because precipitation of the pigment occurs. However, when a pigment-based coloring material is not used, the weather resistance of the image,
It is disadvantageous in terms of paper versatility.

Further, in the case of the above-mentioned ink jet printer, since the pressure is constantly applied, the responsiveness and the viscosity of the electrorheological fluid are reduced, the deterioration of the ejection means is promoted, and the life of the device itself is shortened. There was a problem.

In the case of the above-mentioned ink jet printer, if a line head is used, a number of energy generating devices for discharging the recording material corresponding to the number of heads are required or the size thereof needs to be increased. There was a problem that it became cost.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a print head having excellent image weather resistance and excellent versatility in paper. It is an object of the present invention to provide an image recording apparatus having a long life and realizing a line head at a low cost.

[0010]

That is, according to the first aspect of the present invention, an image is formed by causing a droplet in which a pigment color material is dispersed in an insulating electrorheological fluid to fly from a nozzle in accordance with a recording signal. A recording head having at least one stirring member for dispersing and charging the pigment-based coloring material and capable of applying an electric field for controlling a supply amount of the coloring material in the vicinity of the nozzle. In order to solve the above-mentioned problem, the image forming apparatus is configured to selectively discharge a color material from a nozzle by a charge generation unit corresponding to the print head and record an image.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an ink jet printer as an image recording apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a color material tank for storing a pigment-based color material using an electrorheological fluid as a solvent, and 2 denotes a lower end of the color material tank 1 so as to communicate with the color material tank 1. Nozzles arranged according to a predetermined recording density as shown in FIG. 2 and color material discharge ports 3 for discharging the color material. Reference numeral 4 denotes a stirring member for charging and dispersing the pigment particles contained in the coloring material. As shown in FIGS. 1 and 2, the stirring member 4 has a rod-shaped or thin plate-shaped member 4 directed toward the outer periphery in the radial direction.
a, a plurality of rod-shaped or thin plate-shaped members 4
By rotating a at a predetermined rotation speed about the rotation shaft 4b, the color material in the color material tank 1 is stirred, thereby preventing sedimentation of pigment particles in the color material. The nozzles 2 are arranged for each pixel as shown in FIG. Further, the color material tank 1 and the stirring member 4
Is desirably common to each nozzle 2.
It is also possible to provide for each nozzle 2.

Reference numeral 5 denotes an electric field generating means for generating an electric field for discharging the color material, which is disposed at a position facing the print head 6 and generates an electric field for transferring the color material to the belt-shaped intermediate transfer member 7. It is for. Note that various means can be used for forming the electric field, and the electric field can be directly transferred to the recording medium 8. In FIG.
Reference numeral 11 denotes a transfer roll for transferring an image made of a color material from the intermediate transfer body 7 to the recording medium 8.

Reference numerals 9a and 9b denote electrodes for applying a parallel electric field to the color material discharge port 3 for changing the viscosity of the electrorheological fluid in order to control the supply amount of the color material.
This is an electrode for forming an electric field perpendicular to the color material discharge port 3 in order to discharge from the color material discharge port 3.

The coloring material 10 is called an electrorheological fluid as a solvent, and is a solid fine particle such as a hydrated polymer fine particle or a ceramic fine particle (for example, a sulfonated polymer particle) characterized by having a high viscosity when a voltage is applied. ) Is dispersed in an electrically insulating liquid such as mineral oil or silicone oil, or a fluid such as a liquid crystal, which is made of a substance in which molecules are oriented by an electric field and exhibit anisotropy (for example, liquid crystal polysiloxane).
Further, a pigment-based coloring material such as a toner is dispersed therein. By using this pigment as a coloring material, it is possible to provide an image recording apparatus excellent in image weather resistance and paper versatility.

Next, the operation will be described. When a recording signal is input, first, the stirring member 4 operates in the color material tank 1 to disperse the pigment-based colorant 12 in the solvent 13 and charge the same. Next, an electric field in a direction perpendicular to the color material discharge port 3 is generated by the electric field
Is printed by electrostatic force. As described above, since the color material 10 is caused to fly from the position facing the print head 6 by the electrostatic force, it is not necessary to always keep the inside of the print head 6 in a pressurized state. Print head 6
Longer lifespan. Further, since the color material discharge device is not provided in the print head 6, a line head can be realized at low cost. FIG. 2 shows a conceptual diagram thereof.

In the nozzle 2 to which the recording signal has been input, the voltage is turned off or applied very weakly (0 to 1000 V / mm) between the electrodes 9a and 9b to reduce the viscosity of the particles 13 of the electrorheological fluid. The colorant 12 is lowered so that the colorant 12 can easily fly (see FIG. 3B). In addition, since the viscosity changes according to the intensity of the applied electric field, the electrodes 9a, 9
The discharge color material amount can be controlled by changing the voltage between b.

Conversely, for the nozzle 2 to which no recording signal is input, the voltage between the electrodes 9a and 9b (1000 to 400)
0 V / mm) is applied, the viscosity of the coloring material 10 increases,
Even when a vertical electric field is applied to the color material discharge port 3, the color material 10 does not fly (see FIG. 3A). At this time, the voltage is adjusted so that the shearing stress of the coloring material 10 becomes 1000 Pa or more, more preferably 1500 Pa or more.

As described above, the color material 10 is discharged from the nozzle 2 to which no voltage is applied between the electrodes 9a and 9b or to which a weak voltage is applied, and the voltage is applied between the electrodes 9a and 9b. The color material 10 is not discharged from the nozzle 2 to which the voltage is applied. Therefore, by changing the potential difference between the electrodes 9a and 9b in accordance with the presence or absence of a recording signal, image formation is performed by selectively controlling the discharge of the coloring material.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

The coloring material 10 contained in the coloring material tank 1 is, for example, phthalocyanine blue (toner) having a particle size of about 0.2 μm and sulfonated polymer particles manufactured by Nippon Shokubai Co., Ltd. at a concentration of 160 μg / cc. Was mixed in an insulating oil. This coloring material 10 shows an electrorheological effect,
The step stress under no electric field is 200 Pa or less. The dependence of the viscosity of the coloring material used in the present embodiment on the electric field strength is as shown in FIG. The stirring member 4 is rotated at 60 rpm,
At the same time that phthalocyanine blue was dispersed in the solvent, the coloring material 10 was charged to 600 μC / g. However,
If the charge amount of the color material 10 is 400 to 800 μC / g,
The rotation speed of the stirring member 4 is not limited to this. Electrodes 9a, 9
A voltage of 500 V / mm is formed between the electrode 9c and the electric field generating means 5 using an elastic roll having a resistance of 10 ⁷ Ω without applying a voltage between the electrodes b, and a polyimide intermediate transfer having an area resistance of 12 log Ω / □. The color material 10 is caused to fly over the body 7 and
Print recording at 0 dpi was performed. As a result, the optical density of solid printing was 1.0.

Also, a voltage of 1000 V / m is applied between the electrodes 9a and 9b.
When a voltage of at least m was applied, the coloring material 10 did not adhere to the intermediate transfer belt 7 even when an electric field of 500 V / mm was formed between the elastic roll 5 and the electrode 9c. Further, in a state where an electric field of 500 V / mm is formed between the electric field generating means 5 and the electrode 9c, the voltage between the electrodes 9a and 9b is turned on every other pixel.
When the turning-off was repeated, a high-quality recorded image was obtained on the intermediate transfer member 7 in which adjacent dots did not overlap with each other.

[0024]

As described above, according to the present invention, it becomes possible to uniformly disperse a pigment-based coloring material in a solvent by using a stirring member. Recording apparatus capable of performing image recording excellent in performance and general versatility of paper.

Further, since the coloring material is caused to fly by the electric field generating means provided at a position facing the print head, it is not necessary to constantly pressurize the inside of the head, and it is possible to extend the life of the print head. Since a pressurizing device such as a piezoelectric element is not required for each print head, a line head can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an ink jet printer as an image recording apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a print head of an ink jet printer as an image recording apparatus according to one embodiment of the present invention.

FIGS. 3A and 3B are configuration diagrams respectively showing a recording state of an image of an ink jet printer as an image recording apparatus according to an embodiment of the present invention.

FIG. 4 is a graph showing a relationship between applied voltage and shear stress in an ink jet printer as an image recording apparatus according to one embodiment of the present invention.

[Explanation of symbols]

1: color material tank, 2: nozzle, 3: color material discharge port, 4: stirring member, 5: electric field generating means, 6: print head, 7:
Intermediate transfer member, 8: recording medium, 9a, 9b, 9c: electrode,
10: coloring material, 11: transfer roll.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideaki Ohara 430 Nakaicho Sakai, Ashigara-gun, Kanagawa Prefecture Inside Green X-Tech Fuji Xerox Co., Ltd. (72) Inventor Yoshiyuki Kitazawa 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Eizo Kurihara 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Akihiko Noda 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (reference) 2C056 EA04 EA13 EA21 EA24 EC07 EC42 EC43 ED01 FA07 FC01 FD11 FD11 FD13 KC30 2C057 AF21 AF65 AF99 AG12 AH07 AH09 AN05 BD05 CA01

Claims (1)

[Claims] An image recording apparatus for recording an image by flying droplets in which a pigment-based color material is dispersed in an insulating electrorheological fluid from a nozzle in response to a recording signal. A print head that has at least one stirring member for dispersion and charging, and that can apply an electric field for controlling the supply amount of the coloring material in the vicinity of the nozzle, is provided with a charge generation unit corresponding to the print head. An image recording apparatus for selectively discharging a color material and recording an image.