Incremental printing of symbolic information – Thermal marking apparatus or processes – With transfer medium or driving means therefor
Reexamination Certificate
2001-10-19
2002-08-20
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
With transfer medium or driving means therefor
Reexamination Certificate
active
06437814
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing apparatus such as of a thermal transfer type, designed for use on an information processing apparatus and a communication apparatus. More particularly, it relates to a structure for deciding which portion of an ink sheet is used to print the ink sheet on a sheet of record paper in a printing system that rewinds the ink sheet in order to use the ink sheet a number of times.
2. Description of the Related Art
A thermal transfer printing system in which heat dissipated by a thermal head transfers ink of an ink sheet to a sheet of record paper in order to print the ink sheet on the sheet of record paper is well known. This art is in widespread use on printing apparatus such as a facsimile telegraph and a word processor. Although a one-time ink sheet printable single time prevails as an ink sheet employed in the printing apparatus, an ink sheet printable several times becomes even more popular.
Japanese Unexamined Patent Publication JP-A 59-207276 (1984) discloses a first prior art that copes with a one-time ribbon used on a serial thermal transfer printer. More specifically, a previously print area of the ribbon is compared with an area of the ribbon scheduled for printing, and the ink ribbon is rewound by one row when no overlap occurs between the compared two areas as mentioned above.
Japanese Unexamined Patent Publication JP-A 4-128053 (1992) discloses a second prior art that takes care of a multi-strike ink ribbon (an ink ribbon printable several times). More specifically, the number of times of use of a ribbon cassette is recorded, and pressure on a printing head is controlled in dependence upon the recorded number of times of use.
Japanese Unexamined Patent Publication JP-A 5-147242 (1993) discloses a third prior art in a thermal transfer printing apparatus that employs a multi-pass ink ribbon. More specifically, a temperature table for application on a thermal head is selectively used according to an ink ratio achieved until previous printing.
Japanese Unexamined Patent Publication JP-A 5-147296 (1993) discloses a fourth prior art in which an accumulated ratio of ink on a ribbon surface until previous printing is calculated, and an unused surface of the ink ribbon is used to practice the next printing when the accumulated ink ratio exceeds a certain level of ratio.
Even with the use of a multi-pass ink sheet or an ink sheet printable several times at the same position of the ink sheet, transfer printing is usually conducted a limited number of times. An increased number of times of transfer inevitably degrade printing quality in stages. Accordingly, the ink sheet is preferably subjected to uniform printing and ink transfer. When the ink sheet at first used is rewound for re-use, then an error in traveling of a crimped ink sheet caused by printing makes it difficult to expect that each portion of the ink sheet would be returned to the same position precisely.
There has been a need for a method for equalizing a consumption amount of ink on the ink sheet. In the fourth prior art (JP-A 5-147296) as previously discussed, the ink sheet is rewound each time when a page is printed, and a comparison is made between a previously printed bit map and a bit map to be now printed. In view of an error in traveling of the ink sheet, it would be very difficult to virtually employ a method for determining the number of times of printing according to a printing overlap per bit unit. Alternatively, the number of times of printing is determined from an accumulated ink ratio. When it is determined simply from the accumulated ink ratio at the entire print area on a page how the ink sheet is used, then the ink sheet ends up with inefficient use because there are found an area heavily worn out by printing and having a partially increased ratio of accumulated ink and a virtually non-print area that is excluded from the entire accumulated ink ratio.
SUMMARY OF THE INVENTION
An object of the invention is to provide an ink sheet type-printing apparatus designed to efficiently use an ink sheet while allowing an invariable level of printed image quality to be maintained.
Embodiments of the invention will now be summarized. In an information-processing apparatus and a communication apparatus, in which a recording method is employed for using a rewound ink sheet at least two times in a thermal transfer printing system that thermally transfers ink from the ink sheet onto a sheet of record paper, the thermal transfer printing system being used in a printing apparatus that is incorporated in the information-processing apparatus and the communication apparatus such as a facsimile telegraph and a Japanese language version of a word processor, the ink sheet is divided into several blocks in a virtual manner; first accumulated printing ratio &eegr;
1
for each of the blocks is stored, which can also be called a ratio of dots already printed; second accumulated printing ratio &eegr;
2
for each of the blocks according to an image scheduled for printing is calculated; calculated second ratio &eegr;
2
is compared with stored predetermined value &eegr;
0
of the ink sheet; and, print areas R
1
to Rp are decided without the use of any print area having an increased consumption amount of ink, so as to average a total of evaluation values G for print areas R
1
to Rp including the blocks.
The ink sheet is partitioned into a plurality of blocks in a virtual manner as large as compensating an error in which the ink sheet is traveled in a sub-scanning direction thereof. First and second accumulated printing ratios &eegr;
1
, &eegr;
2
of the ink sheet are determined for each of the partitioned blocks. Evaluation value G is determined from first and second accumulated printing ratios &eegr;
1
, &eegr;
2
for each of the print areas. Print areas of the ink sheet, which are scheduled for printing, are decided to provide an average amount of ink used on the entire ink sheet. As a result, the ink sheet can economically be used. A reduced error in traveling of the ink sheet allows the ink sheet to be used more economically.
The invention provides an ink sheet type-printing apparatus designed to use an ink sheet in recording on a sheet of record paper a number of times at a same position thereof, comprising:
moving means for permitting the ink sheet to be moved in a sub-scanning direction of thereof;
first calculating means for dividing the ink sheet in a virtual manner into a plurality of blocks in both a main scanning direction of the ink sheet and the sub-scanning direction thereof, and further for calculating accumulated printing ratios &eegr;
1
, &eegr;
2
for each of the blocks, which correspond to amounts of ink to be consumed for printing;
second calculating means in response to an output from the first calculating means, for calculating an evaluation value for each of a plurality of print areas different in the sub-scanning direction of the ink sheet,
the evaluation value being related to accumulated printing ratios &eegr;
1
, &eegr;
2
; and,
print area-deciding means in response to an output from the second calculating means, for deciding a print area of the ink sheet to be used, according to the evaluation value, and for forcing the moving means to move the ink sheet in the sub-scanning direction of the ink sheet in order to carry out printing on a sheet of record paper using the decided print area of the ink sheet.
According to the invention, the first calculating means calculates accumulated printing ratios &eegr;
1
, &eegr;
2
for each of the blocks of the ink sheet, while the second calculating means calculates evaluation value G for each of print areas R
1
to Rp according to accumulated printing ratios &eegr;
1
, &eegr;
2
. Print areas R
1
to Rp are displaced in the sub-scanning direction of the ink sheet. The print area-first accumulated printing ratio &eegr;
1
for each of the blocks of the ink sheet, which is obtained after the ink sheet is printed, and the second calculating means calculates evaluation value r
Abe Shingo
Shimonaga Sadaaki
Sharp Kabushiki Kaisha
Tran Huan
LandOfFree
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