JP2004188919A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder capable of forming an image efficiently by reducing the effect of ink mist on a light source. <P>SOLUTION: The ink jet recorder comprises a recording head ejecting UV-curing ink from an ejection opening toward a recording medium, a platen for supporting the recording medium to face the ejecting surface of the recording head, a light source for irradiating ink ejected from the recording head with light thus curing the ink, and a member transmitting light from the light source. The light transmitting member is disposed removably between the platen and the light source. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus using a photocurable ink.
[0002]
[Prior art]
In general, many ink jet recording apparatuses are currently used because of relatively low noise during printing and good printing quality.
An ink jet recording apparatus uses, for example, a piezo element or a heater element, and discharges ink from a nozzle of a recording head as a fine droplet toward a recording medium such as paper, and allows the ink to permeate or fix the recording medium. An image is formed on the recording medium by moving the relative position of the recording head and the recording medium.
Ink jet recording apparatuses include, for example, a serial head type that forms an image by reciprocating a recording head on a recording medium and transporting the recording medium in a direction orthogonal to the scanning direction of the recording head, and a recording medium. There is a line head type which has a fixed recording head having a nozzle array over a recording width and forms an image by transporting a recording medium in a direction perpendicular to the recording width direction.
[0003]
At present, in the field of printing products and packaging materials, there is a growing need for small-volume production, and small-volume production can be performed at lower cost compared to methods that require plate making, such as gravure printing and flexographic printing. Use of the ink jet system is expanding.
As is well known, materials that do not absorb ink, such as resins and metals, are often used for products and packaging materials for the products.
When such a non-absorbent material is used as a recording medium, a high-viscosity photocurable ink is ejected onto the recording medium and allowed to adhere to the recording medium in order to fix the ink on the recording medium. 2. Description of the Related Art A photocurable ink jet recording apparatus that cures and fixes ink by irradiating light such as ultraviolet rays has been developed.
[0004]
Conventionally, as such a photo-curing type ink jet recording apparatus, an ultraviolet curable type ink jet recording apparatus which uses radical polymerization type ink and irradiates a large amount of ultraviolet rays collectively has been put into practical use (for example, Patent Reference 1).
[0005]
[Patent Document 1]
JP 2001-310454 A (page 4)
[0006]
[Problems to be solved by the invention]
However, when a radical polymerization type ink is used as described above, a relatively large amount of ultraviolet irradiation is required. Therefore, there is a problem in that a high-output light source device is mounted, which leads to an increase in the length of the device and an increase in the manufacturing cost of the device.
In order to solve this problem, it is conceivable to use a cationic polymerization type ink which is not currently put into practical use.However, the cationic polymerization type ink has unstable physical properties such as humidity dependency, and has a property such as reflected light. Due to physical properties that cause a curing reaction by weak light, handling is difficult, making practical use difficult.
For example, the closer the light source is to the recording head due to a demand for miniaturization of the apparatus, the more easily the ink mist adheres to the light source. Then, the attached ink mist receives light from the light source and cures at that position. When the ink adheres and cures, the illuminance decreases accordingly. Therefore, the illuminance required for curing the ink must be secured by removing the attached ink or replacing the light source. However, in order to remove ink from the light source, maintenance is time-consuming because the ink is cured on the light source. On the other hand, when the light source is replaced, the light source itself is replaced before the end of its life, and the light source is wasted accordingly.
[0007]
An object of the present invention is to provide an ink jet recording apparatus capable of efficiently forming an image by reducing the influence of ink mist on a light source.
[0008]
[Means for Solving the Problems]
The ink jet recording apparatus according to the first aspect of the present invention,
A recording head that discharges a photo-curable ink from a discharge port to a recording medium,
A platen that supports the recording medium so as to face a discharge surface of the recording head;
Irradiating the ink ejected from the recording head with light, and a light source for curing the ink;
A light transmitting member that transmits light from the light source,
The light transmitting member is detachably disposed between the platen and the light source.
[0009]
According to the first aspect of the present invention, since the light transmitting member is disposed between the platen and the light source, the light transmitting member covers the front in the irradiation direction of the light source, and transmits light while transmitting the light. This can also prevent ink from adhering to the light source. For this reason, since the ink does not easily adhere to the light source itself, the light source need only be replaced when the light source reaches the end of its life, and the light source is not wasted.
Further, since the light transmitting member is detachably disposed, even if the ink adheres to the light transmitting member and causes a decrease in illuminance, even if the ink that has landed on the recording medium does not show a curing reaction, the light transmitted by the ink does not The illuminance required for the curing reaction can be ensured only by replacing the member with a new light transmitting member. As described above, since the illuminance can be ensured only by replacing the light transmitting member without replacing the light source, it is possible to efficiently perform image formation without requiring much time for maintenance.
[0010]
According to a second aspect of the present invention, in the inkjet recording apparatus according to the first aspect,
The light transmitting member transmits light in a wavelength range of 400 nm or less.
[0011]
According to the second aspect of the present invention, since the light transmitting member transmits light in a wavelength range of 400 nm or less, the recording medium is not irradiated with light in a wavelength range higher than this light. Can be prevented.
[0012]
According to a third aspect of the present invention, in the inkjet recording apparatus according to the first or second aspect,
The distance between the light transmitting member and the platen is set to be wider than the distance between the ejection surface and the platen.
[0013]
According to the third aspect of the present invention, since the light transmitting member and the platen are separated from each other at a wider interval than the distance between the ejection surface of the recording head and the platen, the light transmitting member is located closer to the light source than the ejection surface. The ink mist generated by the ejection of ink can be more effectively prevented from reaching the light source.
[0014]
The invention according to claim 4 is the inkjet recording apparatus according to any one of claims 1 to 3,
It is characterized by including a cover member that covers the portion other than the portion covered by the light transmitting member and protects the light source.
[0015]
According to the fourth aspect of the present invention, since the cover member covers the portion other than the portion covered by the light transmitting member to protect the light source, the path of the ink mist to the light source is blocked by the light transmitting member and the cover member. In addition, ink mist reaching the light source can be further reduced.
[0016]
The invention according to claim 5 is the inkjet recording medium according to any one of claims 1 to 4,
The light source irradiates ultraviolet rays to cure the ink.
[0017]
According to the fifth aspect of the present invention, since a light source for irradiating ultraviolet rays is used to cure the ink, the curability can be improved and the cost can be further reduced as compared with the case where a light source for irradiating other light is used. Can be.
[0018]
The invention according to claim 6 is the inkjet recording apparatus according to any one of claims 1 to 5,
It is characterized in that a cationic polymerization type ink is used as the ink.
[0019]
According to the sixth aspect of the invention, even if the cationic polymerization type ink is ejected, it is possible to prevent the image quality from becoming uneven depending on the type of recording medium.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus 1 according to the present embodiment.
[0021]
The ink jet recording apparatus 1 is a serial type ink jet recording apparatus that forms an image with a cationic polymerization type ink while scanning a recording head in a direction perpendicular to a conveying direction of a recording medium. The inkjet recording apparatus 1 includes a platen 2 that supports a recording medium from below, and a carriage 3 that scans in a direction perpendicular to the recording medium transport direction is provided above the platen 2. I have.
[0022]
On the carriage 3, a plurality of recording heads 4 for ejecting inks of each color (Y: yellow, M: magenta, C: cyan, K: black) include a recording medium supported by the platen 2 and an ejection surface 41. It is mounted so as to face each other. A plurality of ejection ports for ejecting ink are linearly arranged on the ejection surface 41 of the recording head 4 along the recording medium conveyance direction.
Further, the carriage 3 is provided with a light irradiation device 5 for curing the ink that has landed on the recording medium so as to be alternately arranged with the recording head 4 along the scanning direction.
[0023]
Hereinafter, the light irradiation device 5 will be described in detail with reference to FIG. FIG. 2A is a front view illustrating a schematic configuration of the light irradiation device 5, and FIG. 2B is a side view.
As shown in FIG. 2A, the light irradiation device 5 includes, for example, rod-shaped light sources 51a and 51b having no directivity, which irradiate the recording medium with light, and are substantially parallel to the row direction of the ejection ports. A plurality of rows are arranged so as to line up.
[0024]
Here, as the light sources 51a and 51b, various light sources that emit ultraviolet light, an electron beam, X-rays, visible light, infrared light, or the like can be used. Illuminating light sources are preferred. As a light source for irradiating ultraviolet light having no directivity, for example, a fluorescent lamp, a mercury lamp, a metal hydride lamp and the like can be mentioned. Examples of the light source that emits directional ultraviolet rays include an LED and an ultraviolet laser.
[0025]
The light irradiation device 5 is provided with a cover member 52 that covers the light sources 51a and 51b in a state where the light sources 51a and 51b are opened in front of the irradiation direction. The inner surface of the cover member 52 is mirror-finished so that the scattered light is reflected and directed in the irradiation direction. At the lower end of the cover member 52, a light transmitting member 53 that transmits light from the light sources 51a and 51b is detachably provided so as to cover the opening. When the light transmitting member 53 is attached to the cover member 52, no gap is formed between them. That is, the light transmitting member 53 prevents ink mist generated during image formation from adhering to the light sources 51a and 51b. The light transmitting member 53 is configured to be disposed between the light sources 51a and 51b and the platen 2 by being detachably attached to another member, even if the light transmitting member 53 is not detachably attached to the cover member 52. You may.
[0026]
The location of the light transmitting member 53 is set such that the distance R2 between the light transmitting member 53 and the platen 2 is wider than the distance R1 between the ejection surface 41 of the recording head 4 and the platen 2. Accordingly, the light transmitting member 53 is disposed at a position closer to the light sources 51a and 51b than the discharge surface 71, and the ink mist generated by the discharge of the ink can more effectively reach the light sources 51a and 51b. To prevent it. In addition, the ink does not easily adhere to the light transmitting member 53, and the life of the light transmitting member 53 can be maintained.
The light transmitting member 53 may be any material that can transmit light and block the invasion of ink, and examples thereof include a glass or resin filter, a prism, and a lens. Further, it is preferable to transmit light in a wavelength range of 400 nm or less in consideration of the temperature influence on the recording medium.
[0027]
Further, the inkjet recording apparatus 1 is provided with a control unit for controlling each drive unit. The control unit is connected to an input unit to which an instruction at the time of image formation is input, and a storage unit, and based on an instruction from the input unit, controls various devices according to a control program or control data written in the storage unit. Control.
The control unit is electrically connected to a recording medium transport mechanism, a driving source of the carriage 3, a recording head 4, and light sources 51a and 51b. In addition, other than these, each drive unit of the inkjet recording apparatus 1 is connected to the control unit.
[0028]
Next, the operation of the inkjet recording apparatus 1 according to the present embodiment will be described.
[0029]
First, the operator inputs the type of recording medium used for image formation from the input unit, and then inputs the start of image formation. Then, the control unit causes the carriage 3 to scan, discharges ink from the recording head 4 while turning on the light sources 51a and 51b, and repeats this operation until image formation is completed.
After the image formation is repeatedly performed, the image quality generated when the illuminance of the light sources 51a and 51b is reduced in the image output to the recording medium, such as uneven dot diameter or uncured ink. When the worker recognizes that the problem described above has occurred, the worker removes the light transmitting member 53 used so far from the cover member 52 and attaches a new light transmitting member 53 to the cover member 52. Thereby, the illuminance required for curing the ink is secured.
[0030]
As described above, according to the inkjet recording apparatus 1 of the present embodiment, since the light transmitting member 53 is disposed between the platen 2 and the light sources 51a and 51b, the light transmitting members 53 irradiate the light sources 51a and 51b. Since the front in the direction is covered, it is possible to prevent ink from adhering to the light sources 51a and 51b while transmitting light. Therefore, ink hardly adheres to the light sources 51a and 51b themselves. Therefore, the light sources 51a and 51b may be replaced only when the light sources 51a and 51b have reached the end of their life, and the light sources 51a and 51b may be wasted. Disappears.
[0031]
Further, since the light transmitting member 53 is detachably provided on the cover member 52, even if the ink adheres to the light transmitting member 53 and the illuminance is reduced, the ink that has landed on the recording medium does not show a curing reaction. The illuminance required for the curing reaction can be ensured only by exchanging the light transmitting member 53 with the ink and the new light transmitting member 53. As described above, since the illuminance can be secured only by exchanging the light transmitting member 53 without exchanging the light sources 51a and 51b, it is possible to efficiently perform image formation without requiring time for maintenance.
Further, since the cover member 52 covers portions other than the portion covered by the light transmitting member 53 to protect the light sources 51a and 51b, the light transmitting member 53 and the cover member 52 reduce the path of the ink mist to the light sources 51a and 51b. The ink mist that is blocked and reaches the light source can be further reduced.
[0032]
It is needless to say that the present invention is not limited to the above embodiment, but can be appropriately changed.
For example, in the present embodiment, the serial type inkjet recording apparatus 1 has been described as an example, but the configuration of the present invention can be applied to a line head type inkjet recording apparatus using a line head as a recording head. is there.
[0033]
【The invention's effect】
According to the first aspect of the present invention, the light transmitting member can prevent ink from adhering to the light source while transmitting light. For this reason, since the ink does not easily adhere to the light source itself, the light source only needs to be replaced when the light source reaches the end of its life, and the light source is not wasted.
Further, since the light transmitting member is detachably disposed, even if the ink adheres to the light transmitting member and the illuminance is reduced, even if the ink that has landed on the recording medium does not show a curing reaction, the light transmitting member to which the ink adheres is not affected. The illuminance required for the curing reaction can be ensured only by replacing the member with a new light transmitting member. As described above, since the illuminance can be ensured only by replacing the light transmitting member without replacing the light source, it is possible to efficiently perform image formation without requiring much time for maintenance.
[0034]
According to the second aspect of the present invention, since the recording medium is not irradiated with light in a wavelength range higher than 400 nm, a rise in the temperature of the recording medium can be prevented.
According to the third aspect of the present invention, the light transmitting member is disposed at a position closer to the light source than the discharge surface, and thus, it is possible to more effectively prevent the ink mist generated by discharging the ink from reaching the light source. be able to.
According to the fourth aspect of the present invention, since the path of the ink mist to the light source is blocked by the light transmitting member and the cover member, the ink mist reaching the light source can be further reduced.
According to the fifth aspect of the present invention, since a light source for irradiating ultraviolet rays is used to cure the ink, the curability can be improved and the cost can be further reduced as compared with the case where a light source for irradiating other light is used. Can be.
According to the sixth aspect of the invention, even if the cationic polymerization type ink is ejected, it is possible to prevent the image quality from becoming uneven depending on the type of recording medium.
[Brief description of the drawings]
FIG. 1 is a side view illustrating a schematic configuration of an inkjet recording apparatus according to an embodiment.
FIGS. 2A and 2B are a front view and a side view showing a light irradiation unit provided in the ink jet recording apparatus of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ink jet recording apparatus 2 Platen 3 Recording head 31 Ejection surface 51a, 51b Light source 52 Cover member 53 Light transmission member R1, R2 Interval

Claims (6)

A recording head that discharges a photo-curable ink from a discharge port to a recording medium,
A platen that supports the recording medium so as to face a discharge surface of the recording head;
Irradiating the ink ejected from the recording head with light, and a light source for curing the ink;
A light transmitting member that transmits light from the light source,
The ink jet recording apparatus according to claim 1, wherein the light transmitting member is detachably disposed between the platen and the light source. The inkjet recording apparatus according to claim 1,
The inkjet recording apparatus according to claim 1, wherein the light transmitting member transmits light in a wavelength range of 400 nm or less. The inkjet recording apparatus according to claim 1, wherein
The inkjet recording apparatus according to claim 1, wherein an interval between the light transmitting member and the platen is set to be wider than an interval between the ejection surface and the platen. The inkjet recording apparatus according to any one of claims 1 to 3,
An ink jet recording apparatus comprising: a cover member that covers a portion other than a portion covered by the light transmitting member and protects the light source. The inkjet recording medium according to any one of claims 1 to 4,
An ink jet recording apparatus, wherein the light source irradiates ultraviolet rays to cure the ink. The inkjet recording apparatus according to any one of claims 1 to 5,
An ink jet recording apparatus, wherein a cationic polymerization type ink is used as the ink.

Images