Incremental printing of symbolic information – Thermal marking apparatus or processes
Reexamination Certificate
2000-03-21
2001-06-12
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
C347S173000
Reexamination Certificate
active
06246426
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink transfer printer which transfers ink to a recording sheet such as a plain paper to form an image thereon.
As a printer which transfers ink onto a recording sheet such as a plain paper, following printers are known: an ink jet printer that jets ink onto the recording sheet from nozzles as liquid particles, a thermal transfer printer that heats an ink ribbon (which can be molten by heat) using a thermal head thereby to transfer the ink onto the recording sheet and a wire dot printer that uses a steel wire for striking ink ribbons against the recording sheet.
However, these known printers have following problems: the ink jet printer may cause a clogging of ink in the nozzle, the thermal transfer printer may increase a running cost due to the consumption of ink ribbons and the wire dot printer is inferior in processing speed. Thus, a printer wherein the ink clogging is prevented and the running cost is small and the processing speed is fast is desired.
SUMMARY OF THE INVENTION
This invention is provided in view of these problems and the object thereof is to provide a printer wherein the ink clogging is prevented, the running cost is small and the processing speed is fast.
To achieve this object, according to one aspect of the present invention, there is provided an ink transfer printer comprising a film using an ink that is a liquid at the room temperature and that allows the permeation of the ink when heated to a predetermined temperature or higher while preventing the permeation of the ink at the room temperature, an ink holder that is in contact with one surface of the film and that holds the ink, a transfer means that makes the other surface of the film contact with the recording sheet and a heating means that selectively heats the film based on print information, wherein a part of the film that is heated by the heating means allows the permeation of the ink from the ink holder so that the ink that has permeated through the film can be transferred to the recording sheet by the transfer means.
Since the use of the film that permeates the ink at elevated temperatures while preventing the permeation of the ink at the room temperature is used, the ink does not remain in the film except when required, thereby preventing a clogging of the ink in the nozzle. In addition, since the ink holder can be used until the ink contained in the ink holder has been used up, the use of the ink holder is efficient, compared with the use of ink ribbons that may be wasted despite the presence of unused parts. It reduces the number of replacement operations and reduces running costs.
The film may be formed by dispersing an additive in a matrix. The matrix has a larger thermal expansion coefficient than the additive. This provides a characteristic in which the ink is transmitted at elevated temperatures while it is not transmitted at the room temperature. In addition, the additive may be an inorganic substance and the matrix may be resin or rubber. The matrix of the film and the ink holder may be the same material so that the ink holder and the film can be integrally formed.
In addition, the ink holder may be roller-shaped and the film may cover the outer circumference of the ink holder so as to allow the ink holder and the film to constitute a roller member. In this case, the transfer means may include a platen roller faced to the roller member so that the recording sheet can be fed between through the platen roller and the roller member when the roller member is rotated. This arrangement enables the ink to be continuously transferred to the recording sheet with a simple constitution.
By setting the linear expansion coefficient of the matrix of the above film larger in the circumferential direction of the roller member than in the axial direction of the roller member, the accuracy of ink transfer in the main scanning direction can be improved when a thermal line head is used. In addition, by locating the heating means below the roller member, the ink can be used as long as it remains in the bottom of the ink holder even if the remaining amount of the ink in the ink holder is small. That is, the ink can be used efficiently.
Further, a color printer can be configured by providing a plurality of sets of the ink holder and the film, impregnating the plurality of ink holders with different color inks, using the heating means to heat the plurality of films based on print information for each color and sequentially contacting the recording sheet with the plurality of films. The plurality of sets of the ink holder and the film constitute a plurality of roller members disposed in parallel. In addition, in case the heating means is a thermal line head having a plurality of arrays of heating elements corresponding to the plurality of films, a single image forming control circuit can be used for each color to reduce costs.
According to another aspect of the present invention, there is provided an ink transfer printer using an ink roller having an ink holder that holds ink and a film that covers the ink holder and that allows the permeation of the ink when heated to a predetermined temperature or higher while preventing the permeation of the ink at the room temperature. The printer rotates the ink roller and heats the film based on print information to selectively allow the permeation of the ink so that the ink permeated through the film can be transferred to the recording sheet. The printer is further provided with an vibrating means that vibrates the ink holder in the ink roller.
Since the ink holder is vibrated, the fluidity of the ink held in the ink holder can be increased. That is, the density of the ink in the ink roller is uniformized. This can uniformize the concentration of the ink transferred to the recording sheet in order to prevent non-uniform printing. The vibrating means may include a piezoelectric element. In addition, the piezoelectric element may be installed on the outer circumference of the rotating shaft of the ink roller. This arrangement enables the ink holder to be uniformly vibrated from the interior.
In addition, if a vibration detection means is further provided for detecting the magnitude of vibration applied to the ink holder by the vibrating means and the vibrating means is controlled based on a value detected by the vibration detection means, it is possible to perform a feedback control. In this case, the printer may further include an image variable-density setting means for setting the variable density of images transferred to the recording sheet so that a control unit can control the vibrating means based on a value set by the image variable-density setting means and a value detected by the vibration detection means. With this arrangement, it is possible to obtain images with a desired variable density by controlling the vibrating means. Furthermore, the vibration measuring means may be a piezoelectric sensor disposed so as to be in contact with the outer circumference of the ink roller. Specifically, the piezoelectric sensor may be provided on the outer circumferential surface of the roller member (for example, a platen roller that presses the recording sheet between itself and the ink roller) that is in contact with the outer circumferential surface of the ink roller.
According to further aspect of the present invention, there is provided an ink transfer printer there is provided an ink transfer printer having an ink roller with an ink holder that holds ink and a film that covers the ink holder and that allows the permeation of the ink when heated to a predetermined temperature or higher while preventing the permeation of the ink at the room temperature and with a rotation shaft that holds the ink holder. The printer rotates the ink roller and heats the film based on print information to selectively allow the permeation of the ink so that the ink permeated through the film can be transferred to the recording sheet. The printer is provided with a heating means in the ink roller for heating the ink holder.
Sinc
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Tran Huan
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