JP2004090320A - Computer-to-print system and method for computer-printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a computer-to-print system which can easily variably print in a high quality by properly suppressing a running cost. <P>SOLUTION: This computer-to-print system includes an image cylinder 2 having a photosensitive thin film 2b formed on a front surface and having characteristics for polarity converting a hydrophobic property into a hydrophilic property by irradiating with an ultraviolet laser, a light irradiating unit 1 for irradiating the thin film with the laser 1a having a light intensity distribution corresponding to information to be printed, a water coating part 3 for coating the thin film irradiated with the laser with water, and an ink coating part 4 for coating the thin film coated with the water with the ink. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plateless printing machine and a plateless printing method.
[0002]
[Prior art]
Generally, printing methods are roughly classified into plate printing and plateless printing. Plate printing requires not only planographic printing but also a printing plate. The printing plate may be prepared in a process different from the printing process, or may be performed on a printing press.
[0003]
On the other hand, in plateless printing using ink, there are cases where an image is formed on an image cylinder by thermal transfer, and cases where an image is formed electrically on an image cylinder. In plateless printing using liquid toner or solid toner, printing is performed by forming an image electrically or electromagnetically.
[0004]
[Problems to be solved by the invention]
In plate printing, as long as the same printing plate is used, only the same printing can be performed. On the other hand, plateless printing has an advantage that desired variable information can be printed, that is, variable printing can be easily performed. However, conventional plateless printing has a disadvantage that running costs are relatively high.
[0005]
The present invention has been made in view of the above-described problems, and provides a plateless printing machine and a plateless printing method capable of performing variable printing with high quality and easily while suppressing running costs satisfactorily. With the goal.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, an image cylinder having a photosensitive thin film formed on the surface thereof, which has a property of converting the polarity from hydrophobic to hydrophilic by irradiation with an ultraviolet laser,
A light irradiation unit for irradiating the photosensitive thin film with an ultraviolet laser having a light intensity distribution corresponding to information to be printed,
A water application unit for applying water to the photosensitive thin film irradiated with the ultraviolet laser,
A plateless printing machine comprising: an ink application unit for applying ink to the photosensitive thin film to which water has been applied.
[0007]
According to a preferred aspect of the present invention, the photosensitive thin film contains an organic polymer containing titanium oxide fine particles. Further, it is preferable that the water application section and the ink application section include a water roll and an ink roll that rotate in contact with the image cylinder that is driven to rotate.
[0008]
According to another aspect of the present invention, a photosensitive thin film having a property of converting polarity from hydrophobic to hydrophilic by irradiation with an ultraviolet laser is formed on the surface of an image cylinder, and a light intensity distribution corresponding to information to be printed is formed. Irradiating the photosensitive thin film with an ultraviolet laser having, applying water to the hydrophilic region of the photosensitive thin film irradiated with the ultraviolet laser, applying ink to the hydrophobic region of the photosensitive thin film coated with water, A plateless printing method is provided, wherein the ink applied to the photosensitive thin film is transferred to a printing substrate while rotating the image cylinder. In this case, it is preferable that the wavelength range of the ultraviolet laser be 400 to 480 nm with a high energy density.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram schematically illustrating a configuration of a plateless printing press according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the basic principle of the plateless printing method according to the present embodiment.
[0010]
Referring to FIG. 1, the plateless printing press of the present embodiment includes a light irradiation unit 1, an image cylinder 2, a water roll 3, an ink roll 4, a blanket cylinder 5, and an impression cylinder 6. . The image cylinder 2 is set so as to be driven to rotate about its axis 2a, and a photosensitive thin film 2b having a characteristic of changing the polarity from hydrophobic to hydrophilic by irradiation with an ultraviolet laser is formed on the surface thereof. The function of the photosensitive thin film 2b will be described later.
[0011]
The light irradiation section 1 has a function of irradiating the photosensitive thin film 2b with an ultraviolet laser 1a having a light intensity distribution corresponding to information to be printed. The water roll 3 is set so as to rotate about the axis 3a while being in contact with the image cylinder 2, and has a function of applying water to the photosensitive thin film 2b irradiated with the ultraviolet laser 1a. The ink roll 4 is set so as to rotate about the axis 4a while abutting on the image cylinder 2, and has a function of applying ink to the photosensitive thin film 2b to which water has been applied.
[0012]
The blanket cylinder 5 is configured to be driven to rotate around the axis 5 a in the direction opposite to the image cylinder 2 while being in contact with the image cylinder 2. The impression cylinder 6 is configured to be rotationally driven around the axis 6a in a direction opposite to the blanket cylinder 5 (that is, in the same direction as the image cylinder 2) while abutting on the blanket cylinder 5. A sheet (sheet) 10 as a printing material passes between the blanket cylinder 5 and the impression cylinder 6, and printing is performed at that time.
[0013]
Next, the basic principle of the plateless printing method according to the present embodiment will be described with reference to FIG. For example, when a water drop is dropped on the photosensitive thin film 2b containing the organic polymer containing the titanium oxide fine particles, the contact angle θ becomes a considerably large value due to the surface tension of the water drop 11, as shown in FIG. In other words, the surface of the photosensitive thin film 2b exhibits hydrophobicity when not excited by ultraviolet light.
[0014]
On the other hand, as shown in FIG. 2B, when the surface of the photosensitive thin film 2b on which the water droplet 11 is formed is irradiated with the ultraviolet laser 12, the surface tension is almost lost and the contact angle becomes almost zero. As a result, the water droplet 11 cannot maintain its shape, and extends thinly over the surface of the photosensitive thin film 2b. In other words, the surface of the photosensitive thin film 2b changes from hydrophobic to hydrophilic by irradiation with the ultraviolet laser.
[0015]
FIG. 2C shows a state in which water and ink are sequentially applied after partially irradiating the surface of the photosensitive thin film 2b with an ultraviolet laser. In this case, the region changed from hydrophobic to hydrophilic by irradiation with the ultraviolet laser constitutes a region that receives water and does not receive ink, that is, a water receiving region (hydrophilic region) 13a. On the other hand, a region that maintains hydrophobicity without being irradiated with the ultraviolet laser constitutes a region that receives ink without receiving water, that is, an ink receiving region (hydrophobic region) 13b.
[0016]
In the present embodiment, the above-described basic principle is used. That is, in the present embodiment, the light irradiation unit 1 irradiates the photosensitive thin film 2b formed on the surface of the image cylinder 2 with an ultraviolet laser 1a having a light intensity distribution corresponding to information to be printed, for example, by digital control. . In this way, it becomes possible to form a latent image on the surface of the photosensitive thin film 2b corresponding to the information to be printed.
[0017]
Then, water is supplied to the surface of the photosensitive thin film 2b irradiated with the ultraviolet laser 1a via the water roll 3 and oil-based ink is supplied via the ink roll 4 by a method similar to the conventional offset printing. As a result, only water is received in the hydrophilic region 13a of the photosensitive thin film 2b irradiated with the ultraviolet laser 1a, and only oil-based ink is received in the hydrophobic region 13b of the photosensitive thin film 2b coated with water.
[0018]
The image pattern formed on the surface of the photosensitive thin film 2b with the oil-based ink in this manner is transferred to the surface of the paper 10 as the printing object via the blanket cylinder 5 by a method similar to the conventional offset printing. The hydrophilic region can be restored to a hydrophobic region by heating (heat irradiation, heat conduction, etc.) the photosensitive thin film 2b. As a result, the image pattern formed on the surface of the photosensitive thin film 2b by the irradiation of the ultraviolet laser 1a is obtained. Can be erased.
[0019]
In other words, in this embodiment, desired variable printing can be easily performed by repeating the latent image of the image pattern by the irradiation of the ultraviolet laser 1a and the erasure of the image pattern by heating. Further, in the present embodiment, the oil-based ink can be used according to the same method as the conventional offset printing, so that it is easy to additionally install the existing equipment, the running cost is suppressed well, and the variable printing is performed with high quality. And easily.
[0020]
In the present embodiment, for example, by using an ultraviolet laser having a wavelength of 400 nm to 480 nm and having a high energy density, the time for converting the polarity from hydrophobic to hydrophilic can be greatly reduced. Further, in the present embodiment, since the photosensitive thin film 2b contains titanium, it is possible to realize a plateless printing machine having high durability and printing durability.
[0021]
【The invention's effect】
As described above, in the present invention, the oil-based ink can be used according to the same method as the conventional offset printing, so that it is easy to additionally install the existing equipment, and the running cost can be suppressed, and the variable printing can be performed. Can be easily performed with high quality.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of a plateless printing press according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a basic principle of a plateless printing method according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light irradiation part 1a, 12 Ultraviolet laser 2 Image cylinder 2b Photosensitive thin film 3 Water roll 4 Ink roll 5 Blanket cylinder 6 Impression cylinder 10 Paper 11 Water drop 13a Hydrophilic area (water receiving area)
13b hydrophobic area (ink receiving area)

Claims (5)

An image cylinder in which a photosensitive thin film having a property of converting the polarity from hydrophobic to hydrophilic by irradiation with an ultraviolet laser is formed on the surface,
A light irradiation unit for irradiating the photosensitive thin film with an ultraviolet laser having a light intensity distribution corresponding to information to be printed,
A water application unit for applying water to the photosensitive thin film irradiated with the ultraviolet laser,
A plateless printing machine comprising: an ink application unit for applying ink to the photosensitive thin film to which water has been applied. The plateless printing press according to claim 1, wherein the photosensitive thin film contains an organic polymer containing titanium oxide fine particles. The plateless printing press according to claim 1, wherein the water application unit and the ink application unit include a water roll and an ink roll that rotate in contact with the image cylinder that is driven to rotate. Form a photosensitive thin film on the surface of the image cylinder, which has the property of converting the polarity from hydrophobic to hydrophilic by irradiation with an ultraviolet laser,
Irradiate the photosensitive thin film with an ultraviolet laser having a light intensity distribution corresponding to the information to be printed,
Applying water to the hydrophilic region of the photosensitive thin film that has been irradiated with the ultraviolet laser,
Applying ink to hydrophobic areas of the photosensitive thin film to which water has been applied,
A plateless printing method, wherein the ink applied to the photosensitive thin film is transferred to a printing substrate while rotating the image cylinder. The plateless printing method according to claim 4, wherein the wavelength range of the ultraviolet laser is 400 nm to 480 nm.

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