Incremental printing of symbolic information – Thermal marking apparatus or processes – Including cooling device
Reexamination Certificate
2001-02-08
2002-05-21
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Including cooling device
C347S197000
Reexamination Certificate
active
06392682
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printer device, and more particularly relates to a printer device having a heat radiating or cooling mechanism for the heat generating component, which helps to produce a more compact thermal transfer printer.
2. Description of the Related Art
In recent years we have seen analog or digital, moving or still image signals produced by electronic cameras, as well as image data produced by computer (hereinafter referred to merely as image signals) displayed on CRTs, liquid crystal devices, and other such monitors, and also printed out on recording paper.
A printer device that prints the image of an image signal on recording paper has an ink ribbon produced by applying a thermal transfer ink coating (either meltable or thermal dye sublimation type) to a thin film, and then the ink ribbon is laid over a platen roller along with the recording paper. The printer device feeds the superposed ink ribbon and recording paper while pressing them between the platen roller and a thermal head, during which time a current corresponding to the image signal is applied to the thermal head, which heats the head and melts or sublimates the thermal transfer ink in the ink ribbon and transfer-prints it onto the recording paper.
The thermal head of a printer device comprises a plurality of heat generating elements arranged in a line in the longitudinal direction of the recording paper, perpendicular to the conveyance direction. The ink ribbon and the recording paper are squeezed between this thermal head and the platen roller, and when the recording paper and the ink ribbon are fed between the thermal head and the platen roller, the heat generating elements are heated according to the image signal data, so that the ink in the ink ribbon is thermally transferred to the recording paper.
Recording with a thermal head involves varying the heating energy of the heat generating elements of the thermal head, and thereby varying the density of the ink coating transferred from the ink ribbon, and allowing gradation to be expressed. Accordingly, if the temperature of the thermal head goes over a certain maximum, the density of the transferred ink coating cannot be accurately controlled. Also, heat build-up in the thermal head can produce shading that leads to inconsistent density of the image transferred onto the recording paper.
In view of this, a printer device is generally provided with a cooling means for monitoring the temperature of the thermal head and keeping this temperature from rising above the temperature range at which the density of the ink coating can be accurately controlled.
Techniques pertaining to the cooling or heat-radiation of this thermal head have been disclosed in Japanese Laid-Open Patent Applications H6-255141 and H6-47991.
Japanese Laid-Open Patent Application H6-255141 discloses a technique for attaching a thermistor, for detecting the temperature of a thermal head, to the thermal head, finding the difference between a rated temperature and the temperature of the thermal head, and controlling the rotational speed of a cooling fan according to this temperature differential. As the temperature of the thermal head climbs, the speed of the cooling fan is raised to increase the amount of air blown at the thermal head. Once the detected temperature drops below the rated temperature, the cooling fan is stopped.
Japanese Laid-Open Patent Application H6-47991 discloses a technique in which a thermal conduction component for allowing the heat from the head base of a thermal head to escape through an upper cover (forming the casing) is provided between the head base and the upper cover.
In addition to these, Japanese Laid-Open Patent Application H8-112951 discloses a technique pertaining to the cooling or heat-radiation of a thermal head, in which the thermal head attachment base is attached directly to a heat-radiating upper cover, and Japanese Laid-Open Patent Application H5-112022 discloses a method in which a thermal head is fixed to a chassis and the heat is radiated through this chassis, among other proposals.
What all these disclosures have in common is that images of the desired gradation can be printed by transferring the ink coating of the ink ribbon at the optimal temperature.
However, the method for controlling a cooling fan disclosed in Japanese Laid-Open Patent Application H6-255141 requires the provision of various circuit functions for comparing with a reference temperature on the basis of a temperature signal detected by a thermistor, and controlling the rotation of the cooling fan on the basis of the difference from this reference temperature. Therefore, the circuit structure of the printer device is more complicated, and the provision of this circuit structure is also a problem in that it makes the printer device bulkier and more expensive.
With the methods discussed in Japanese Laid-Open Patent Applications H6-47991 and H8-112951, in which a thermal conduction component is provided for allowing the heat from the base of the thermal head to escape through the upper cover, or the base for attaching the thermal head is attached to the heat-radiating upper cover, a cooling fan must further be provided in case sufficient heat radiation is impossible. Accordingly, space must be left for the installation of a cooling fan in the vicinity of the thermal conduction component or the attachment base, and this is a problem in that it makes the printer device bulkier.
Furthermore, when the thermal head is fixed to the chassis and heat is radiated through this chassis, as disclosed in Japanese Laid-Open Patent Application H8-112022, the platen roller must be able to swing with respect to the thermal head, and this swing mechanism for the platen roller is complicated, which is again a problem in that it makes the printer device bulkier.
The present invention was conceived in light of the above problems encountered in the past, and it is an object thereof to provide a printer device having a heat radiating or cooling mechanism which helps to produce a more compact thermal transfer printer.
SUMMARY OF THE INVENTION
The printer device of the present invention makes use of a thermal head to transfer ink to recording paper on a platen roller, and comprises a thermal head support member, cooling means, and a support member that supports the cooling means. The thermal head support member has a support component that supports the thermal head, and a recess provided to the back side, which is the opposite side from the support component, and is movably disposed between a transfer position where the ink is transferred and a retracted position to which the thermal head support member is retracted from the transfer position. The cooling means radiates the heat generated by the thermal head. The support member supports the cooling means such that at least part of the cooling means will enter the recess when the thermal head support member is moved to its retracted position.
Also, the printer device of the present invention comprises an arm, heat radiating means, and a setback. The arm has a heat generating component for transferring ink, rotatably disposed between a transfer position where the ink is transferred onto a recording medium and a retracted position to which the arm is retracted from the transfer position. The heat radiating means is supported so as to be located within the movement path that is defined as the arm rotates, and radiates the heat generated by the heat generating component of the arm. The setback is provided to the back of the arm so as to avoid interference between the heat radiating means and the arm when the arm has moved to the retracted position.
REFERENCES:
patent: 5-112022 (1993-05-01), None
patent: 6-047991 (1994-02-01), None
patent: 6-255141 (1994-09-01), None
patent: 8-112951 (1996-05-01), None
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Olympus Optical Co,. Ltd.
Tran Huan
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