Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2000-12-22
2004-05-18
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S104000, C355S117000, C399S272000, C399S273000, C399S313000, C399S312000
Reexamination Certificate
active
06736500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to image forming methods and apparatus to inject a liquid drop including color material according to an image signal to form an image on a transfer medium, and more particularly relates to image forming methods and apparatus that transfer an image formed by liquid drops having been increased in viscosity onto a recording medium and that separate the recording medium from the transfer medium.
2. Related Art
Ink jet printers have become widely used with a recent improvement in the performance not only for a small volume recording but also for a large volume recording such as ones for use in an office or for incorporation in a production equipment. With such expansion of the field of use of ink jet printers, a demand has increased for recording an image on a sheet of high quality plain paper with less blotting. In ink jet printers, formation of an image on a sheet of plain paper without blotting has been one of most important technical challenges, demand for which has recently increased more than ever.
For formation of an image on a sheet of plain paper without blotting, various attempts have been made. In particular, a technology to transfer an image onto a sheet of plain paper used as a recording medium via a transfer medium has been regarded as one of the promising technologies, and developments of such a technology have been vigorously pursued.
For example, Japanese Patent Laid-open publications Nos. 6-293178 and 7-089067 describe methods of solving blotting of an image on a sheet of plain paper serving as a recording medium. In the methods, an image is once formed with ink jet liquid drops on a transfer medium, and the image is then transferred to a sheet of plain paper when the ink jet liquid drops have changed, through phase transition, for example by being heated, to have a viscosity suitable for being transferred.
However, in the methods described in the JP Laid-open publications No. 6-293178 and 7-089067, a surface active agent is adhered to the transfer medium in advance for increasing the wettability of a transfer medium. Therefore, it takes a certain time for liquid drops, forming an image on the transfer medium, to change to have a viscosity suitable for the transfer, for example by being heated, and the image on the transfer medium tends to blot during that time. In particular, blotting is remarkable in solid parts of an image. Because of such time for waiting for liquid drops to change to have a viscosity suitable for transfer, increasing the printing speed, for example in a line printer, is limited.
Further, for solving the above-described problem in the methods described in JP Laid-open publications 6-293178 and 7-89067, the applicant of the present invention has proposed in Japanese Patent Laid-open publication No. 11-188858 a method in which powder having an absorbing property is adhered onto a transfer medium and the viscosity of ink liquid drops forming an image on the transfer medium is increased by the powder being absorbed by the ink liquid drops in a short time. The ink liquid drops as an image are transferred to a sheet plain paper utilizing increased viscosity of the ink liquid drops, and thereby image blotting in the sheet of plain paper is avoided. This method enables instantly obtaining a clear image having less blotting on a sheet of plain paper. In particular, if liquid ink drops having increased viscosity can be completely transferred to a recording medium, necessity of cleaning a surface of the transfer medium is eliminated, and thereby the transfer mechanism can be simplified and earlier deterioration of the transfer medium can be prevented, which are convenient.
However, it has been revealed by the inventors of the present invention, through minute observation of an image transferred onto a recording medium, that even an image which appears to be satisfactory has some inferior parts. Specifically, a phenomenon has been revealed that some parts of an image, having been transferred onto a recording medium, are omitted due to insufficient viscosity of the image.
Further, in the methods of JP Laid-open publications Nos. 6-126945 and 7-82516 and JP No. 2743151 which use a transfer medium as in the method of JP Laid-open publication No. 11-188858, a problem is known that some parts of an image are not transferred when liquid drops forming the image, which have been increased in the viscosity, are not well caught in the fibers of a sheet of paper serving as a recording medium.
In addition to the above-described problem relating to viscosity of liquid drops, another problem is known that uneven image transfer occurs if contact between a sheet of paper and a transfer medium is insufficient when transferring an image.
Still furthermore, a problem is known that inadequate separation of a recording medium from a transfer medium remarkably influences the quality of a transferred image as in insufficient transfer of the image.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-discussed and other problems and addresses the above-discussed and other problems.
Accordingly, preferred embodiments of the present invention provide a novel image forming method and a novel image forming apparatus, in which good transfer of an image onto a recording medium from a transfer medium is achieved, ink liquid drops having been increased in the viscosity are sufficiently tangled with fibers of paper serving as the recording medium such that occurrence of partially uneven transfer of the image is avoided, and the performance of image fixing on the recording medium is improved.
Further, preferred embodiments of the present invention provide a novel image forming method and a novel image forming apparatus that achieve good contact between a recording medium and a transfer medium when transferring an image from the transfer medium to the recording medium, such that ink liquid drops having been increased in the viscosity are sufficiently tangled with fibers of paper serving as the recording medium, and thereby partially uneven image transfer is avoided and image fixing performance is improved.
Still furthermore, preferred embodiment of the present invention provide a novel image transfer method and a novel image transfer device that transfer an image to a recording medium from a transfer medium by pressing the recording medium to the transfer medium and that then smoothly separate the recording medium from the transfer medium.
According to a preferred embodiment of the present invention, a method of forming an image includes steps of causing a material, that increases a viscosity of liquid drops by contact with the liquid drops, to adhere to a transfer medium, causing a liquid drop to contact the material according to an image signal such that an image is formed with the liquid drop having been increased in viscosity by contact with the material, and transferring the image formed by the liquid drop having been increased in viscosity to a recording medium. Viscosity of a liquid drop when increased on the transfer medium by contact with the material is set such that the liquid drop adheres to the recording medium and such that the liquid drop is transferred to the recording medium without being divided into a part remaining on the transfer medium and another part being transferred to the recording medium. By the above-described image forming method, good image transfer is realized and thereby an image having no blotting is obtained.
According to the invention, in the above-described method, viscosity of a liquid drop when increased by contact with the material may be between 10,000 cps (centipoise) and 200,000 cps. By setting viscosity of a liquid drop when increased by contact with the material in such a range, an image of good quality is obtained.
Further, an interval of the material to adhere to the transfer medium may be made smaller than a diameter of the liquid drop when the liquid drop contacts the transfer medium. Thereby, it never occurs that some liquid dro
Hasebe Mitsuo
Noguchi Aino
Takahashi Tomoko
Tanikawa Kiyoshi
Meier Stephen D.
Tran Ly T
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