JPH02212147A - Image forming method - Google Patents

Abstract

PURPOSE:To form an image without using a jetting and driving force generating source such as a piezoelectric vibrator by employing for a recording body an electric viscous fluid where coloring material is dispersed or dissolved in an insulating solvent and impressing an electric field at least at one place in the vicinity of a part where a jetting channel is installed. CONSTITUTION:An appropriate pressing means such as a pump 5 supplies the recording body 7 with pressure that cannot jet the body by itself from an orifice 1 to a recording body supply channel 6. The recording body 7 circulates in the recording body supply channel 6. When an electrode 4 disposed downstream of the circulation of the recording body impresses an electrode on the recording body 7 from the recording body jetting channel 2 installed on the recording body supply channel 6, the viscosity of a part of the recording body 7 on which an electric field has been impressed increases to stop the circulation of the recording body 7 in the supply channel 6. The recording body 7 is led to a solvent jetting channel 2, and is jetted out as a liquid drop 3 from the orifice 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method in which an image is formed by ejecting droplets from a recording medium through an orifice.

[Prior Art] A conventional image forming method in which an image is formed by ejecting droplets of a recording medium from an orifice is disclosed in USP-3946, for example.
This was a method typified by No. 398 (Kyser method).

The Kyser method applies an electrical recording signal to a piezoelectric vibrator attached to a recording head that has an orifice for ejecting a recording medium, and converts the electrical recording signal into mechanical vibration of the piezoelectric vibrator. Recording is performed by ejecting droplets from the recording medium from the orifice according to mechanical vibrations and adhering them to the recording member.

[Problems to be Solved by the Invention] However, the conventional image forming method described above requires an ejection driving force generation source such as a piezo vibrator for ejecting the recording material, and as a result, the recording material ejection mechanism itself becomes expensive. The problem was that it was easy to do so.

The present invention is intended to solve these problems, and its purpose is to provide an image forming method in which an image is formed by ejecting and flying droplets from a recording medium without using a piezo vibrator. It is in.

[Means for Solving the Problems] The image forming method of the present invention is an image forming method in which an image is formed by ejecting and flying droplets of a recording material from an orifice in response to a recording signal, in which an insulating solvent is used as the recording material. The supply flow path of the recording body ejection mechanism uses an electrorheological fluid in which a colorant is dispersed or dissolved, and includes a supply flow path for the recording medium and a discharge flow path for the recording body attached to the supply flow path. An electric field is applied to at least one location near a location where the discharge flow path is attached.

The image forming method of the present invention is characterized in that an electric field is applied to the ejection channel.

[Function] By using a colorant dispersed or dissolved in an insulating solvent, the viscosity of the recording medium increases upon application of an external electric field. Such substances are called electrorheological fluids.

According to the above configuration of the present invention, an electrorheological fluid is used as the recording medium, and the recording body discharge mechanism includes a recording body supply channel and a recording body discharge channel attached to the supply channel. By applying an electric field to at least one location on the downstream side of the recording medium circulation near the point where the flow path is attached, the viscosity of the recording medium, which is an electrorheological fluid, in the supply flow path near the electric field application point increases, and the supply flow Circulation of the recording material in the road is obstructed. The recording medium in the supply flow path flows into the recording medium discharge flow path and is discharged from the orifice, allowing image recording to be performed.

Further, according to the above configuration of the present invention, by applying an electric field to the ejection flow path, the viscosity of the recording medium, which is an electrorheological fluid, in the ejection flow path can be increased. The movement of the recording medium can be controlled. As a result, it is possible to prevent the recording medium from being ejected from the orifice other than when necessary. Furthermore, it is possible to control ejection from ejection channels that are greater in number than the number of ejection drive force generation sources using a small number of ejection drive force generation sources for the recording body.

Electrorheological fluid is a general term for liquids whose viscosity increases with the application of an external electric field, and there are two types: a pure single system consisting only of a solvent, and a particle dispersion system in which a dispersoid is added to a dispersion medium. (Fukuzawa: Hydraulic Technology, vo 1-14+No, 9.
19-23 (1975)) In the case of a pure single system, the magnitude of viscosity change varies depending on the material and electric field strength. In the case of a particle dispersion system, the magnitude of viscosity change varies depending on not only the electric field strength but also the combination of materials and the degree of particle immersion. In general, a larger viscosity change can be obtained in a particle dispersion system than in a pure single system.

In fact, when an electrorheological fluid is used as an image forming material for forming an image by ejecting droplets of a recording medium from an orifice, the following combinations are possible.

■An image-forming material in which the dispersoid doubles as a coloring material in a combination of a dispersion medium and a dispersoid that can be expected to produce an electrorheological effect.

■An image-forming material in which a coloring material is added separately from the dispersoid in a combination of dispersion medium and dispersoid that can be expected to produce an electrorheological effect.

■An image-forming material in which a coloring material is added to a solvent that can be expected to have an electrorheological effect.

Dispersion media that can be used in the present invention include petroleum-based aliphatic hydrocarbons with high insulation properties (electrical resistance of 10"0 cm or more) and low dielectric constants (dielectric constant of 3 or less); for example, hexane, octane, cyclopentane, Hydrocarbon solvents such as benzene, toluene, and quidylol; Examples include halogenated hydrocarbon solvents such as carbon tetrachloride, trichloroethylene, tetrachloroethane, and dichlorobenzene.Dispersoids that can be used in the present invention include silica, Ceramic fine powders such as alumina and titania; iron oxide; carbon black, etc. Colorants that can be used in the present invention include:
Inorganic pigments such as titanium white, iron black, and carbon black; Organic pigments such as phthalocyanine; Direct dyes, basic dyes,
Water-based dyes such as acid dyes; Water-insoluble dyes such as sulfur dyes, oil-soluble dyes, chromium dyes, and reactive dyes.

By the way, the viscosity required for the recording medium in an image forming method in which image formation is performed by ejecting and flying droplets of the recording medium from an orifice is usually 1 to 4 cP, preferably, when the recording medium ejection flow path diameter is about 100 μm. 2-3 cP, 1 oc
If the viscosity is higher than p, the recording medium cannot be ejected from the orifice. Therefore, in order to use an electrorheological fluid in a recording medium, it is necessary that the electrorheological fluid normally has a viscosity of 2 to 3 cP, and that the viscosity increases to 10 cP or more when a voltage is applied. The composition of recording media can be classified into aqueous and non-aqueous based on the main solvent, and the main solvent can include dyes,
Anti-clogging agents, disinfectants, anti-mold agents, etc. are in dissolved or dispersed form.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Embodiment 1 FIGS. 1A to 1C are a schematic view, a side view, and a front view of an orifice of a recording medium discharge mechanism according to an image forming method according to an embodiment of the present invention.

As the recording body 7 which is an electrorheological fluid, 0.0% is added to kerosene.
2 μm carbon black dispersed (viscosity coefficient
2cP, 20°C) was prepared. The recording material 7 was supplied into the recording material supply channel 6 having a diameter of 1 mm using an appropriate pressurizing means such as a pump 5 at such a pressure that it could not be discharged from the orifice 1 by itself. The recording medium 7 was circulated in the recording medium supply channel 6. 100 attached to the recording medium supply channel 6
When an electric field is applied to the recording medium 7 using an electrode 4 disposed downstream of the recording medium circulation from the recording medium discharge channel 2 having a diameter of μm, the viscosity of the recording medium 7 in the area where the electric field is applied is increased, and the circulation of the recording medium 7 in the supply channel 6 was stopped.

The recording medium 7 was introduced into the recording medium discharge channel 2 and was discharged from the orifice 1 in the form of droplets 3.

Next, the electric field applied by the electrode 4 was set to 0n-off at 3kHz.
f, the ejection of the recording medium 7 also followed the on-off of the electric field.

When an inkjet printer head was prepared using the recording material ejection mechanism of this example and an image was formed, a good image without any scattering of the recording material was obtained. Furthermore, neither carbon black precipitation nor orifice 1 clogging occurred.

Note that the composition of the recording medium 7, the diameter of the recording medium supply channel 6, and the diameter of the recording medium discharge channel 2 are not limited to those described above. Furthermore, the structure of the electrodes 4 for applying an electric field is not limited to the shape shown in FIG. 1 in which the supply channel 6 is sandwiched from above and below, but may also be structured such that it is sandwiched from the left and right sides. .

Example 2 An inkjet printer head was prepared in the same manner as in Example 1, except that kerosene in which 0.01 μm silica particles and 0.02 μm carbon black were dispersed was used as the recording medium 7. When an image was formed, a good image was obtained without any scattering of the recording material. Furthermore, neither carbon black precipitation nor orifice 1 clogging occurred.

Example 3 An inkjet printer head was prepared in the same manner as in Example 1, except that Direct Black 154 dissolved in water treated with an ion exchange resin was used as the recording medium 7, and image formation was performed. However, a good image was obtained without any scattering of the recording material. Furthermore, neither carbon black precipitation nor orifice 1 clogging occurred.

Embodiment 4 FIGS. 2A to 2C are a schematic view, a side view, and a front view of an orifice of a recording medium discharge mechanism in another embodiment according to the image forming method of the present invention.

As the recording body 7 which is an electrorheological fluid, 0.0% is added to kerosene.
2 μm carbon black dispersed (viscosity coefficient
2cP, 20°C) was prepared. The recording material 7 was supplied into the recording material supply channel 6 having a diameter of 1 mm using an appropriate pressurizing means such as a pump 5 at such a pressure that it could not be discharged from the orifice 1 by itself. The recording medium 7 was circulated in the recording medium supply channel 6. 10 attached to the recording medium supply channel 6
An electric field is applied to the recording medium 7 by an electrode 4 disposed on the downstream side of the recording medium circulation from the recording medium discharge channel 2 having a diameter of 0 μm.
When the n-off was performed at 3kHz, the electric field was turned on.
-off, the viscosity of the recording medium 7 changed. The viscosity of the recording medium 7 in the portion to which the electric field was applied increased, and the ○ circulation in the supply channel 6 of the recording medium 7 was stopped. The recording material 7 is introduced into the recording material ejection channel 2, and is ejected as a droplet 3 from the orifice 1.Next, the electric field is applied on and off to the recording material 7 by the electrode in the same way as before. When an electric field was applied using an electrode 8a disposed near the recording medium ejection flow path 2 at 3kHz and the viscosity of the recording medium 7 was increased in the area where the electric field was applied, the viscosity of the recording medium 7 was increased from the orifices 1b, 1c, and 1d. , the recording material 7 was ejected as droplets 3, but the recording material 7 was not ejected from the orifice 1a. Thereafter, by similarly applying an electric field to the electrode 8 near any orifice 1 and turning on and off the electric field by the electrode 4, droplets of the recording medium 7 could be ejected from any orifice 1.

Recording body ejection 8 of this embodiment! When an inkjet printer head was created using this structure and an image was formed, a good image was obtained without any scattering of the recording material. Furthermore, neither carbon black precipitation nor orifice 1 clogging occurred.

Note that the composition of the recording medium 7, the diameter of the recording medium supply channel 6, and the diameter of the recording medium discharge channel 2 are not limited to those described above.

[Effects of the Invention] As described above, according to the present invention, in an image forming method in which an image is formed by ejecting and flying droplets of a recording material from an orifice in response to a recording signal, an insulating solvent is used as the recording material. The supply flow path of a recording body ejection mechanism that uses an electrorheological fluid in which a coloring material is dispersed or dissolved and includes a supply flow path for the recording medium and a discharge flow path for the recording body attached to the supply flow path. By applying an electric field near the attachment point of the ejection flow path, it is possible to form an image by ejecting droplets from the recording medium without using an ejection driving force generation source such as a piezo vibrator. have

Further, according to the present invention, by applying an electric field to the ejection flow path, it is possible to turn on and off the ejection of the recording medium, and there is an effect that the integration of the recording medium ejection flow path is facilitated.

[Brief explanation of the drawing]

FIG. 1(a) is a schematic diagram of a recording medium ejecting mechanism in an embodiment according to the image forming method of the present invention, FIG. 1(b) is a side view of the recording medium discharging mechanism in an embodiment according to the image forming method of the present invention, FIG. 1(c) is a front view of an orifice of a recording medium discharge mechanism in an embodiment of the image forming method of the present invention. FIG. 2(a) is a schematic diagram of a recording material ejection mechanism in another embodiment according to the image forming method of the present invention, and FIG. 2(b) is a schematic diagram of a recording material ejection mechanism in another embodiment according to the image forming method of the present invention. FIG. 2(c) is a front view of an orifice of a recording medium discharge mechanism in another embodiment according to the image forming method of the present invention. Recording body electrode Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki (1st name) Orifice discharge flow path Droplet electrode pump supply flow path Figure 2 (a) Figure 2 (b) Figure 2 (C)

Claims (2)

[Claims] (1) In an image forming method in which an image is formed by ejecting and flying droplets of a recording medium from an orifice in response to a recording signal,
A recording body using an electrorheological fluid in which a colorant is dispersed or dissolved in an insulating solvent as the recording body, and comprising a supply channel of the recording body and a discharge channel of the recording body attached to the supply channel. An image forming method characterized in that an electric field is applied to at least one location in the supply flow path of a discharge mechanism near a location where the discharge flow path is attached. (2) The image forming method according to claim 1, wherein an electric field is applied to the discharge flow path.