Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-04-14
2001-12-04
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S040000
Reexamination Certificate
active
06325486
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to image recording methods, and in particular, to an image recording method in which the upper and lower bands of a recording head are overlapped for recording, and recording data for a plurality of dots in the overlapping recording area are assigned to the upper and lower bands when recording is performed.
2. Description of the Related Art
In general, thermal transfer printers are widely used as output apparatuses for computers, word processors, etc., because of high recording quality, low noise, low cost, and ease of maintenance.
In these typical thermal transfer printers, paper is supported in front of a platen, and a heating-element-formed thermal head is mounted on a carriage. While the thermal head and the carriage are reciprocally moved along the platen when an ink ribbon and the paper are supported between the thermal head and the platen, the ink ribbon is reeled out, and power is selectively supplied, based on recording information, to the heating elements, whereby a portion of ink is transferred from the ink ribbon onto the paper so that images such as the desired characters are recorded on the paper.
These thermal transfer printers have problems in that, due to paper feeding errors or the like, an area recorded by one scan of the thermal head, and an area recorded by the next scan are so close to each other that a so-called “black line” is generated, and in that the areas are conversely so far apart that a so-called “white line” is generated.
By way of example, in the case where basic dots comprised of an N×M dithering matrix are used as basic cells, and recording is performed at a negative screen angle, with the basic cells used so as to be shifted downward in the scanning direction of the thermal head, when the feeding amount of the paper is approximate, as shown in
FIG. 54
, the distance between a recording area (upper band) formed by one scan of the thermal head, and a recording area (lower band) formed by the next scan of the thermal head, is uniform.
When the feeding amount of the paper is too small as shown in
FIG. 55
, the distance between the upper and lower bands narrows to generate a black line. When the feeding amount of the paper is too large, the distance between the upper and lower bands increases to generate a white line. The generated black line and white line are visually undesirable, and greatly affect recording image quality.
Accordingly, in order to prevent black lines and while lines from being generated, a conventional recording method is employed in which the upper and lower bands overlap.
FIG. 57
shows the outline of the conventional recording method. According to the conventional recording method, when a thermal head has, for example, 240 heating dots, recording is performed using an upper band and a lower band to overlap so that the 237th, 238th, 239th, and 240th dots in the upper band respectively correspond to the 1st, 2nd, 3rd, and 4th dot in the lower band. Recording data for the four common dots are assigned to the upper and lower bands.
In assignment of the recording data, in the overlapping recording area (for four bits), while the dots of the thermal head in the arrangement direction (column direction) are being identified, recording data are assigned for each column to the upper and lower bands. In other words, in the case where all four dots in the first column have recording data, as shown in
FIG. 57
, among the data in the four dots, the first and second dot data are assigned to the upper band, and the third and fourth dot data are assigned to the lower band. In the second column, the first dot data is assigned to the upper band, and the third and fourth dot data are assigned to the lower band. In the third column, the first dot is assigned to the lower band.
As described above, the conventional recording method performs recording in an overlapping recording area by appropriately assigning, for each column, recording data in the dots of a thermal head to upper and lower bands, and driving, based on the assigned recording data, heating elements as the dots.
The conventional thermal transfer printers have a problem in that the processing amount of recording data is extremely large, substantially delaying processing speed since the recording data in dots are assigned for each column. Therefore, in recording that must process a large amount of recording data, such as the case where multigradation recording is performed by controlling, for example, a time for supplying power to the heating dots of a thermal head, and changing the diameter of each dot, a further problem occurs in that high speed recording cannot be performed because the processing of the recording data is insufficient so that recording speed is reduced.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an image recording method for performing high speed recording by greatly increasing recording-data processing speed and for obtaining high-quality recording images by preventing white lines and black lines from appearing in images.
It is another object of the present invention to provide an image recording method for providing a simplified technique of assigning recording data, compared with a conventional technique of assigning recording data for each column, and for easily and rapidly processing recording data by substantially reducing the amount of processing.
It is still another object of the present invention to provide an image recording method for performing the fixed-form assignment of recording data in accordance with a plurality of groups of successive flags provided to the dots having the recording data.
It is a further object of the present invention is to provide an image recording method for using three colors, cyan, magenta, and yellow to perform the appropriate recording of full color images.
It is a still further object of the present invention to provide an image recording method for performing the appropriate recording of monochrome images by assigning monochrome recording data.
To these ends, according to an aspect of the present invention, the foregoing objects are achieved through provision of an image recording method including the steps of feeding recording paper so that recording is performed by using an upper band as a recording area formed by one scan of a recording head, and a lower band as a recording area formed by the next scan of the recording head so as to overlap in a plurality of dots; performing assignment of recording data in the dots in the overlapping recording area to the upper band and the lower band; and driving, based on the assigned recording data, the recording elements of the recording head to perform recording; wherein the assignment includes the steps of successively identifying each dot of the recording head in the scanning direction thereof; providing successive flags to the dots when the dots have the recording data; and assigning, to the upper band and the lower band, the recording data in the successive dots provided with the successive flags only when no recording data is detected.
According to another aspect of the present invention, the foregoing objects are achieved through provision of an image recording method including the steps of feeding recording paper so that recording is performed by using an upper band as a recording area formed by one scan of a recording head, and a lower band as a recording area formed by the next scan of the recording head so as to overlap in a plurality of dots; performing assignment of recording data in the dots in the overlapping recording area to the upper band and the lower band; and driving, based on the assigned recording data, the recording elements of the recording head to perform recording; wherein the assignment includes the steps of successively identifying each dot of the recording head in the scanning direction thereof; providing successive flags to the dots when the dots have the recording data; and dividing, into two groups, the recordi
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Le N.
Nguyen Lamson D.
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