Photocopying – Using microcapsules
Reexamination Certificate
1998-12-29
2001-06-05
Adams, Russell (Department: 2851)
Photocopying
Using microcapsules
C355S032000, C355S033000, C430S138000
Reexamination Certificate
active
06243161
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image-forming liquid medium containing microcapsules filled with dye or ink, and to an image-forming apparatus that forms an image on a sheet of recording paper by selectively developing monochromatic dots, when using such an image-forming liquid medium, in accordance with a series of digital image-pixel signals.
2. Description of the Related Art
Conventionally, an image-forming system, using an image-forming sheet coated with a layer of microcapsules filled with dye or ink, is known. In this image-forming sheet, a shell of each microcapsule is formed of a suitable photo-setting resin, and an optical image is recorded and formed as a latent image on the layer of microcapsules by exposing it to light rays in accordance with image-pixel signals. Then, the latent image is developed by exerting pressure on the microcapsule layer. Namely, the microcapsules, which are not exposed to the light rays, are squashed and broken, whereby the dye or ink seeps out of the squashed and broken microcapsules, and thus the latent image is visually developed by the seepage of the dye or ink.
Of course, in this conventional image-forming system, it is impossible to form an image on a sheet of ordinary printing paper without the layer of microcapsules. Nevertheless, usually, only a small portion of the microcapsules included in the layer contributes to the formation of an image on the image-forming sheet. In other words, a large portion of the microcapsules included in the layer are not utilized for the formation of an image on the image-forming sheet. Thus, in the conventional image-forming system, a large amount of ink or dye, encapsulated in the microcapsules, is wastefully consumed by not taking part in the formation of an image.
Also, each of the image-forming sheets must be packed so as to be protected from being exposed to light, resulting in wastage of materials. Further, the image-forming sheets must be handled such that they are not subjected to excess pressure due to the softness of unexposed microcapsules, resulting in an undesired seepage of the dye or ink.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a novel image-forming liquid medium containing a plurality of microcapsules filled with dye or ink, by which an image can be formed on a sheet of recording paper.
Another object of the present invention is to provide an image-forming apparatus that forms an image on a sheet of recording paper by selectively generating dots, when using the above-mentioned image-forming liquid medium, in accordance with a series of digital image-pixel signals, thereby developing monochromatic dots on a sheet of recording paper by squashing and breaking the microcapsules included in each drop.
In accordance with an aspect of the present invention, there is provided an image-forming liquid medium comprising a solution that contains a surface-active agent; and at least two types of microcapsule: a first type of microcapsule filled with a first dye, and a second type of microcapsule filled with a second dye, which are homogeneously mixed with the solution. The first type of microcapsule exhibits a first pressure/temperature characteristic such that, when the first type of microcapsule is squashed and broken under a first predetermined pressure at a first predetermined temperature, the first dye seeps from the squashed and broken microcapsule, and the second type of microcapsule exhibits a second pressure/temperature characteristic such that, when the second type of microcapsule is squashed and broken under a second predetermined pressure at a second predetermined temperature, the second dye seeps from the squashed and broken microcapsule.
The image-forming liquid medium may further comprise a third type of microcapsule filled with a third dye mixed with the solution together with the first and second types of microcapsule, and the third type of microcapsule exhibits a third pressure/temperature characteristic such that, when the third type of microcapsule is squashed and broken under a third predetermined pressure at a third predetermined temperature, the third dye seeps from the squashed and broken microcapsule.
In this image-forming liquid medium, the first type of microcapsule may have a first shell wall composed of a first resin which exhibits the first pressure/temperature characteristic, the second type of microcapsule may have a second shell wall composed of a second resin which exhibits the second pressure/temperature characteristic, and the third type of microcapsule has a third shell wall composed of a third resin which exhibits the third pressure/temperature characteristic.
Preferably, each of the first, second and third resins exhibit transparency, and each of the first, second and third dyes exhibit transparency, with the solution exhibiting transparency and further comprising a color developer that reacts with each of the first, second and third dyes, thereby developing a predetermined monochromatic color. Preferably, the respective first, second and third dyes comprise a first leuco-pigment and a second leuco-pigment, respectively, and the respective first, second, and third dyes exhibit a cyan pigmentation, a magenta pigmentation and a yellow pigmentation.
In accordance with a second aspect of the present invention, there is provided an image-forming apparatus, using the image-forming liquid medium, as mentioned above, which comprises: a transfer unit that selectively transfers a small part of the image-forming liquid medium as a first fluid drop to a sheet of recording medium in accordance with a first digital monochromatic image-pixel signal, corresponding to the first dye, and that selectively transfers a small part of the image-forming liquid medium as a second fluid drop to the sheet of recording medium in accordance with a second digital monochromatic image-pixel signal, corresponding to the second dye; and a pressure/temperature applicator unit that applies the first predetermined pressure and the first predetermined temperature to the first fluid drop, and that applies the second predetermined pressure and the second predetermined temperature to the second fluid drop.
The transfer unit and the pressure/temperature applicator unit may be combined with each other as a single thermal head assembly.
In this case, the image-forming apparatus further comprises a platen member that is associated with the single thermal head assembly, and the single thermal head assembly includes: an electrically-insulated base member; a first movable thermal head provided in the base member and having a first array of heater elements aligned with each other; a second movable thermal head provided in the base member and having a second array of heater elements aligned with each other, the first array of heater elements being in parallel with the second array of heater elements; a spacer member, having an opening, securely provided on the base member such that the first and second thermal heads are encompassed by the opening of the spacer member; and a sheet of film that covers the spacer member such that the opening of the spacer member is defined as a liquid medium space that stores the image-forming liquid medium, the sheet of film including a plurality of pores formed therein, with the pores being aligned with each other in a first row and a second row, which extend along the first and second arrays of heater elements, respectively, such that each of the heater elements is associated with a corresponding pore, the first fluid drop being produced from one of the pores in the first row by heating a corresponding one of the heater elements in the first array to the first predetermined temperature, the second fluid drop being produced from one of the pores in the second row by heating a corresponding one of the heater elements in the second array to the second predetermined temperature, the platen member urging the first and second thermal heads toward the interposed sheet of film, the
Furusawa Koichi
Orita Hiroshi
Saito Hiroyuki
Suzuki Katsuyoshi
Suzuki Minoru
Adams Russell
Asahi Kogaku Kogyo Kabushiki Kaisha
Brown Khaled
Greenblum & Bernstein P.L.C.
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