Coating processes – Nonuniform coating
Reexamination Certificate
1999-04-07
2002-08-13
Hess, Bruce H. (Department: 1774)
Coating processes
Nonuniform coating
C347S105000, C427S422000, C428S195100, C428S913000, C428S914000
Reexamination Certificate
active
06432481
ABSTRACT:
RELATED APPLICATION DATA
The present application claims priority to Japanese Application No. P10-099021 filed Apr. 10, 1998 which application is incorporated herein by reference to the extent permitted by law.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to recording material, wherein heating with a heating means causes surface tension inclination, generating flow which causes the recording material to fly and be transferred onto a recording medium positioned opposing a transfer portion; and also relates to a recording method using this recording material.
2. Description of the Related Art
In recent years, in accordance with colorizing of video cameras, computer graphics, and so forth, there are increasing needs for color hard copies, not to mention black-and-white recording. With regard to such, color hard-copy printing methods which have been proposed include the dye dispersion thermal transfer method (or sublimation-type thermal transfer method), the melt thermal transfer method, the ink-jet method, the electro-photography method, the thermal-developing silver-salt method, and so forth. Of these, the dye dispersion thermal transfer method and ink-jet method can be classified as examples of methods whereby high-quality images can be easily output from relatively simple devices.
The dye dispersion thermal transfer method-uses an ink ribbon or sheet coated with an ink layer formed by dispersing a high concentration of transfer dye within an appropriate binder resin, and so-called photographic printing sheets which are formed by coating paper with dyeing resin which accepts the transferred dye. The ink ribbon or sheet is pressed against the thermal transfer sheet at a certain pressure, and a thermo-sensitive recording head (thermal head) applies heat from behind the ink ribbon or sheet, thus performing thermal transfer of transfer dye from the ink ribbon or sheet to the thermal transfer sheet, the amount of transfer dye being transferred according to the amount of heat applied to the dye receiving layer.
FIG. 16
shows the configuration of the area surrounding a thermal head of a printer using this dye dispersion thermal transfer method.
A thermal head
61
is positioned so as to oppose a platen roller
68
, and an ink sheet
62
which has been formed by providing an ink layer
64
on a base film
63
, for example, along with a recording sheet
65
formed by coating the surface of paper
66
with a dying resin layer (dye-accepting layer)
67
, and run in the direction of the arrow A while being pressed against the thermal head
61
by the platen roller
68
which rotates in the direction of the arrow B in the Figure.
Then, the ink in the ink layer
64
selectively heated by the thermal head
61
according to the image to be printed is subjected to thermal dispersion into the dying resin layer
67
of the recording sheet
65
which has been heated by coming into contact with the ink layer
64
, and transfer is carried out by dot pattern, for example.
A full-color image having continuous gradients can be obtained by repeating this operation for image signals resolved into the three primary colors of subtractive color mixture, i.e., yellow, magenta, and cyan. Much attention has been given to this dye dispersion thermal transfer method, as the printer can be reduced in size and maintenance thereof is simple, the printer has immediate availability, and images with quality rivaling that of silver-salt color photography can be obtained.
However, this method is problematic in that disposal of the ink ribbon or sheet results in massive amounts of discarded materials and high running costs, which has interfered with widespread use. This is also true for the melt thermal transfer method.
On the other hand, the ink-jet method is a method wherein droplets of recording material (hereafter referred to as “ink”) are discharged from nozzles provided to a printer head according to image information, using methods such as electrostatic gravity, continuous vibration generation (piezo method), thermal (bubble-jet method), and the like, as described in Japanese Patent Publication No. 61-59911, Japanese Patent Publication No. 5-217, and so forth, whereby the flying droplets of ink adhere to the printing paper or the like, thereby conducting recording.
Accordingly, printing can be performed on plain paper, and there are hardly any discarded items generated as with the case of using ink ribbons or the like, so running costs are low. This method is becoming widespread in recent years, since color images can be easily printed with the thermal method.
However, the principle of the ink-jet method makes concentration gradients in pixels difficult, and it has been difficult to realize images with quality rivaling that of silver-salt color photography in a short time, as can be with the above-described dye dispersion thermal transfer method.
That is to say, with the known ink-jet method, one droplet forms one pixel, so this principle makes concentration gradients within pixels difficult, and accordingly, high-quality images could not be realized. Also, pseudo-gradient representations with dithering using the high resolution of ink jets is being attempted, but image quality equal to that of the sublimation type thermal transfer method has not been obtained, and moreover, the transfer speed drastically drops when employing such methods.
In order to solve such problems, a method using so-called mist has been proposed in order to miniaturize the discharged droplets in the ink-jet recording method. This method can be generally divided into (1) the supersonic oscillation method, and (2) the satellite droplet method.
The former (1) is a method wherein mainly piezo oscillators are used to generate supersonic oscillation at the discharging portions, and minute droplets (ink mist) generated by the ink liquid striking against itself due to surface tension vibration caused by this oscillation are transferred. The latter (2) uses fine droplets generated as derivatives immediately following formation of main droplets for forming images, and with this method, the main droplets are not used in the image formation.
However, with the method (1), line heads are hard to form since miniaturization of piezo devices is generally difficult, and there is also the problem of slow speed, common to piezo devices. Also, localizing supersonic oscillations is difficult, making miniaturization even more difficult, and there is much interference from cross-talk, as well. Also, the method (2) requires complicated means such as charging the main droplets and bending the course thereof so the main droplets are not transferred to the recording paper. Such a method is actually restricted to the so-called continuous ink-jet recording method, and it is difficult to realize such at low costs.
The present Applicant has found an ink mist transfer method which solves the above problems.
This is a method wherein ink is caused to fly in the form of mist, using the collision force of ink owing to surface tension convection or the like generated by turning heating means on and off, and this mist is transferred onto a recording medium, thereby forming images of high quality. (refer to Japanese Patent Application No. 10-89030 (Date of Application: Apr. 1, 1998); hereafter referred to as “Invention of Prior Application”).
The Invention of Prior Application causes surface tension inclination at the surface of ink by means of resistance heating or laser beams, generating flow of ink (particularly surface tension convection or Marangoni flow) which causes the ink to fly, so ink can be caused to fly in the form of relatively large mist, this improving the transfer sensitivity per unit time. In this way, the Invention of Prior Application is a recording method which has excellent transfer sensitivity and printing speed.
With this method, providing heaters in high density can be easily realized by using known semiconductor processing techniques, and cross-talk can be prevented by providing appropriate structures on the heater
Hess Bruce H.
Sonnenschein Nath & Rosenthal
Sony Corporation
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