Incremental printing of symbolic information – Thermal marking apparatus or processes
Reexamination Certificate
2000-08-10
2001-08-07
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Reexamination Certificate
active
06271872
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a head cleaning method and device for a thermal printer, and a recording sheet roll for the same. More particularly, the present invention relates to a head cleaning method and device for a thermal printer, and a recording sheet roll for the same, with which a thermal head can be cleaned with good efficiency.
2. Description Related to the Prior Art
There is a thermal printer in which heating elements of a thermal head is pressed against a recording surface of a thermosensitive recording sheet. An image is recorded by color development of the recording sheet. An example of the recording sheet is continuous, and is wound in a form of a recording sheet roll to be loaded in the thermal printer. After the image recording, a cutter in the thermal printer cuts the continuous recording sheet to obtain a print sheet with an image.
A front edge of the recording sheet roll in an unused state is likely to have an unwanted curvature, has an inclination to a direction perpendicular to lateral edges, or other features with low quality. A known model of the thermal printer is constructed to execute a precutting process, in which the front edge of the recording sheet roll is cut neatly upon newly setting the recording sheet roll in the thermal printer. In the precutting process, the continuous recording sheet is drawn from the recording sheet roll. A portion having the front edge is cut away at a predetermined precutting length, and is removed and ejected from the thermal printer. The precutting process, for example, is effected upon detection of closing of a lid for a roll loading chamber after the recording sheet roll is set in the roll loading chamber.
It is likely that dirt, dust or the like sticks to the heating element array of the thermal head. The dirt may have been stuck on the recording sheet. The dust may be particles created from a protective layer in the recording sheet. The thermal head must be cleaned periodically because dirt of the thermal head will influence the printing quality. To clean the thermal head, there is a cleaning sheet roll for maintenance as accessory to the recording sheet roll. The cleaning sheet roll is a roll of a continuous cleaning sheet having an abrasion layer, and has appearance similar to that of the recording sheet roll. The cleaning sheet roll is set in the thermal printer for cleaning operation instead of the recording sheet roll.
When a cleaning command signal is input with the cleaning sheet roll set in the thermal printer, the continuous cleaning sheet is drawn from the cleaning sheet roll, and fed to a position between the thermal head and a platen roller. When a portion of the cleaning sheet with a predetermined length is passed between the thermal head and the platen roller, the cleaning sheet is stopped in a temporary manner. One of the thermal head and the platen roller is moved to the remainder to squeeze the cleaning sheet. The cleaning sheet starts again being fed. The abrasion layer is rubbed on the heating elements to wipe away dirt or dust from those. The cleaning sheet having rubbed the thermal head is cut by the cutter in the same manner as the recording sheet, and is ejected from the thermal printer.
As the thermal printer executes the precutting process automatically, a front portion of the cleaning sheet is automatically precut upon setting of the cleaning sheet roll. This is a wasteful operation, because the precutting process is irrespective of the unused state of the front portion of the cleaning sheet, and discards the front portion in vain. Also, a user is likely to mistake the precutting process for a cleaning process, and remove the cleaning sheet roll without using the cleaning sheet roll for cleaning the thermal head.
SUMMARY OF THE INVENTION
In view of the foregoing problems, an object of the present invention is to provide a thermal printer, a head cleaning method and a recording sheet roll with which a thermal head can be cleaned with good efficiency and without errors in use of a cleaning sheet.
In order to achieve the above and other objects and advantages of this invention, a thermal printer includes a feeder for feeding a continuous recording sheet from a recording sheet roll. A thermal head operates for image recording to the continuous recording sheet being fed. A roll loading station is loaded with one of the recording sheet roll and a cleaning sheet roll, the cleaning sheet roll including a continuous cleaning sheet wound in a roll form, and discernment information provided in a predetermined position. An information reader reads the discernment information. A controller causes the feeder to feed the continuous cleaning sheet when the discernment information is read, to wipe and clean the thermal head with the continuous cleaning sheet.
Furthermore, a cutter precuts the continuous recording sheet in a precutting position separated a predetermined length from a front edge of the continuous recording sheet, to remove a front edge portion.
Furthermore, a platen is disposed to face the thermal head. A shifter mechanism is controlled by the controller, for moving one of the thermal head and the platen toward a remainder thereof while the feeder is actuated, to press the continuous cleaning sheet against the thermal head.
After the thermal head is cleaned, the cutter cuts the continuous cleaning in a cutting position separated a predetermined length from a front edge of the continuous cleaning sheet, to remove a front edge portion.
The controller causes the feeder to move back and forth the continuous cleaning sheet for a predetermined number of times.
The controller keeps the thermal head from being energized while the feeder feeds the continuous cleaning sheet.
The discernment information is a first indicia formed in the continuous cleaning sheet. The information reader includes a photoelectric sensor.
According to one aspect of the present invention, a head cleaning method of cleaning a thermal head includes a step of loading a pre-cleaning recording sheet roll including the continuous recording sheet wound in a roll form, and a cleaning region defined at a front edge portion of the continuous recording sheet. The thermal head is wiped and pre-cleaned with the cleaning region by feeding the cleaning region.
Furthermore, after the pre-cleaning step, the cleaning region is cut away from the continuous recording sheet.
The pre-cleaning recording sheet roll further includes discernment information provided in a predetermined position. Furthermore, the presence or absence of the discernment information is checked, wherein if the discernment information is present, the pre-cleaning step is effected.
The cleaning region comprises a cleaning abrasion layer overlaid on the front edge portion of the continuous recording sheet.
The cleaning abrasion layer is secured by adhesion.
According to another preferred embodiment, the cleaning abrasion layer is overlaid by coating.
REFERENCES:
patent: 5926197 (1999-07-01), Kessler
patent: 60-49985 (1985-03-01), None
patent: 61-43584 (1986-03-01), None
patent: 63-114691 (1988-05-01), None
patent: WO93/21020 (1993-10-01), None
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Tran Huan
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