Incremental printing of symbolic information – Thermal marking apparatus or processes – With transfer medium or driving means therefor
Reexamination Certificate
2000-08-08
2001-09-18
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
With transfer medium or driving means therefor
Reexamination Certificate
active
06292207
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a line thermal head letter printing method of a synchronous type for making a letter printing by feeding a hot release type thermal transfer ribbon tape following a transfer velocity of a print object sheet and especially relates to a line thermal head letter printing method in which feeding and winding of the ribbon tape are improved.
2. Description of the Prior Art
In recent years, there are often cases where letters and marks, such as date of manufacture, tastable time period and series number of manufacture, are printed on a packaging material differently for each of objects to be printed. In such cases, the printing is often done by feeding a hot release type thermal transfer ribbon tape following a transfer velocity of a sheet as an object to be printed, such as a packaging material film, (herein referred to as “a print object sheet”) and by supplying a line thermal head, such as that called a corner edge type or an end face type, which is pressed against the ribbon tape, with electricity.
In case the printing is done on the print object sheet, which is being transferred with a high velocity, by the line thermal head using the hot release type thermal transfer ribbon tape, when a portion to be printed of the print object sheet comes, it is necessary that the ribbon tape is wound to be fed synchronously with the velocity of the print object sheet. For this purpose, that is, in order to wind the ribbon tape to feed it synchronously with the velocity of the print object sheet in time for start of the printing, a rise time is needed.
Because of such rise time, there is necessarily caused a delay in the start of the winding of the ribbon tape. Despite such delay in the start of the winding of the ribbon tape, as the ribbon tape, which is in contact with the print object sheet, is fed upon start of the printing, there may be caused a loosening of the ribbon tape hot release portion at a tip of the head in the initial stage of the printing immediately after the start of the printing, which often results in the problem that there is caused a place where no printing is done at a head portion of the printing or the printing is out of order because of no good hot release, and it has been found that this problem arises in the case where the printing is done on the print object sheet which is being transferred at a high velocity of 10 inch/second or more.
As mentioned above, in the conventional letter printing method for printing letters by using a line thermal head supplied with electricity and a hot release type thermal transfer ribbon tape, there is a problem that a printing of a desired quality may not necessarily be done at the starting time of the printing.
SUMMARY OF THE INVENTION
In view of the problem in the prior art, it is an object of the present invention to provide a line thermal head letter printing method by which a hot release type thermal transfer ribbon tape may be fed synchronously with a transfer velocity of a print object sheet from immediately after a start of printing so that a high quality printing may be obtained.
In order to attain the mentioned object in the letter printing method for printing letters on the print object sheet, which is being transferred, by using the line thermal head and the hot release type thermal transfer ribbon tape, the present invention provides a line thermal head letter printing method comprising steps of: feeding a necessary amount of the ribbon tape at a velocity synchronized with a transfer velocity of the print object sheet by using a stepping motor, and winding the ribbon tape via a friction transmission by a power rotating at a velocity higher than that of the print object sheet being transferred.
By employing the mentioned letter printing method, winding of the ribbon tape is done while the ribbon tape is being stretched via the friction transmission by the power rotating at the velocity higher than that of the transferring print object sheet, thus the ribbon tape is so wound that a tension acts on the ribbon tape continuously, there occurs no loosening of the ribbon tape hot release portion at a tip of the head and the hot release of the ribbon tape takes place always in a good condition.
While a ribbon tape winding side wants to so stretch the ribbon tape at the velocity higher than that of the transferring print object sheet, there is an effect of a torque of the stepping motor provided on a ribbon tape feeding side and the ribbon tape is in no case fed at a velocity higher than that fed by a drive mechanism using the stepping motor.
Also, in the letter printing method according to the present invention, if both of the feeding and the winding of the ribbon tape are done by a roll drive and a feeding amount of the ribbon tape is detected by a rotary encoder, then it will be preferable as an inked face of the ribbon tape may not be damaged.
Thus, according to the letter printing method of the present invention, a clear and high quality printing can be done also on the print object sheet which is being transferred at a velocity higher than 10 inch/second or more with which there has been a problem.
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patent: 0 493 942 (1992-07-01), None
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patent: 9-156144 (1997-06-01), None
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patent: WO 99/34983 (1999-07-01), None
Daisey Machinery Co., Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tran Huan
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