Incremental printing of symbolic information – Thermal marking apparatus or processes
Reexamination Certificate
1998-06-29
2001-02-13
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Reexamination Certificate
active
06188422
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application relates to and incorporates herein by reference Japanese Patent Application No. 09-173328 filed on Jun. 30, 1997.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermal printer control and a computer readable medium for printing an image on a printable medium such as a thermal paper by heat generated from a thermal printer head, and particularly relates to a thermal printer control and a computer readable medium by which printing quality may be improved by controlling timings at which an image is printed on a thermal paper even when sticking occurs between a thermal printer head and the thermal paper.
2. Description of Related Art
Heretofore, there is known a thermal printer apparatus for printing an image on a thermal paper serving as a printable medium by discoloring (blackening) the thermal paper with an application of heat generated from a thermal printer head including a heating element. If the thermal paper that has been discolored in the previous printing operation of one line does not advance and remains at the position of the previous printing as shown by the dotted line in
FIG. 8A
while a feeder roller is in a paper feeding motion as shown by the solid line, the discolored layer of the melted thermal paper is cooled and the thermal paper sticks to the heating element of the printer head. As a result, as shown in
FIG. 8B
, although an image of the next line is printed, the thermal paper
10
does not advance to the next position and the next image is not printed on the next position, thereby resulting in an image of each line
52
being printed on the same position repeatedly. This produces a void (whitening or printed image dropout) on the thermal paper.
It is proposed to prevent this sticking by lowering the quantity of heat of the printer head. However, according to this method, as the heat is not sufficiently applied to thermal paper, an image cannot be printed on the thermal paper with proper density. For this reason, there are also proposed various apparatuses which prevents sticking between a thermal paper and a printer head so that an image can be reliably printed on the thermal paper without lowering the quantity of heat of the printer head when an image is printed on the thermal paper.
Japanese Examined Patent Publication No. Hei 6-83344 proposes that, in a printing mode of a long printing cycle in which sticking tends to occur, after printing of an image of a predetermined amount is finished, a printer head and a thermal paper are immediately moved relatively to prevent sticking.
Japanese Unexamined Patent Publication No. Hei 7-227990 proposes that, in a low speed thermal paper feeding mode in which sticking ends to occur, an image is printed after image data of predetermined lines is accumulated in a memory. In actual practice, the thermal paper is advanced at a comparatively high speed, thereby preventing occurrence of sticking.
However, the conventional apparatuses are unable to control timings at which an image is printed on the thermal paper. Therefore, if sticking occurs for some reason, then the printing timing becomes inappropriate. Thus, a printed image dropout occurs and a printing quality is lowered.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a thermal printer control and a computer readable storage medium which prevents, even when sticking occurs, occurrence of printed image dropout or the like by controlling timings at which an image is printed on a printable medium.
According to the present invention, a thermal paper stop time after a previous paper advance is determined and a delay time is determined in accordance with the paper stop time in which a thermal printing process is effected. The next thermal printing process is effected after the thus determined delay time from a completion of a next paper advancing process. Thus, even when a thermal paper sticks to a thermal printer head, each thermal printing process can be executed after the thermal paper is advanced to a next printing position, thereby preventing the occurrence of printed image dropout.
Preferably, the paper stop time is represented by data to be printed and the delay time is stored in the data table memory in correspondence with the stop time so that the stop time and the delay time may be determined without actual measurement and mathematical calculation for controlling the next printing process.
More preferably, the temperature of the printer head is detected and the delay time is determined from both of the stop time and the detected temperature.
REFERENCES:
patent: 4814789 (1989-03-01), Ono
patent: 61-197259 (1986-09-01), None
patent: 6-83344 (1994-10-01), None
patent: 7-227990 (1995-08-01), None
Brother Kogyo Kabushiki Kaisha
Oliff & Berridge PLC.
Tran Huan
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