Incremental printing of symbolic information – Ink jet – Combined
Reexamination Certificate
1997-12-08
2001-01-09
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Combined
Reexamination Certificate
active
06172688
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a label printer which is widely used, especially in POS, FA, physical distribution, etc., and more particularly to a label printer utilizing an ink jet print system.
2. Related Background Art
Hitherto, none of the label printers using the ink jet printing method have been put to practical use. The advantages of the typical ink jet recording may include excellent quietness owing to out-of-contact with the print medium, high printing rate, printing with high density, easy color constitution, and small size. On the other hand, most label printers take the form of conveying a so-called label sheet having a number of labels bonded in succession on a length of the release sheet referred to as a separator and formed into a roll, in which in applying the ink jet system to the label printer, some measures must be taken to suppress the floating or skew running of the sheet in the printer head portion.
In recent years, the bar code is liable to be insufficient, the color constitution is examined, and from this regard, the adoption of the ink jet system is effective, but if an the printing speed of the label printer is attempted in designing the color label printer, the frequency of the print signal to be given to the print head of each color is increased, which requires the capacity of drive power source to be increased, resulting in larger size of the power source and causing the increase of the cost.
Further, in the case of the ink jet system, to prevent the unstable discharge of the ink because of being left unused for the long term, it is effective to use a so-called recovery system to circulate the ink around the print head. This recovery operation is typically performed with a recovery unit referred to as a recovery system placed in direct contact with the print head which is printing means. However, as the label printer typically utilizes the label sheet wound like a roll, the sheet never disappears at the print position. Accordingly, the disposition of the recovery system and the design of the recovery sequence are very difficult, as compared with those intended for the cut sheet such as the normal office printer.
Along with these, it is very difficult to make compact the print head, the recovery system unit, the ink supply system, and the printing medium conveyance system.
Several normal label printers have been put to practical use, which adopt a thermal transfer recording method of transferring the ink onto the recording medium via the ink ribbon using the heat generating elements, or a thermal recording method of coloring the thermosensible recording sheet by heating.
At present, among the ink jet recording systems using the heat generating elements, there is a bubble jet system (thermal ink jet system) discharging the ink by producing bubbles in the liquid ink due to the heat energy generated by the heat generating elements, and using the pressure generated upon the growth of the bubbles, which is applied to the output devices (printers) in many fields.
The durability of the print head using the above heat generating elements may be governed by the disconnection of a resistor useful as the heat generator, the failure of a switching element such as a transistor for controlling the conduction to each heat generator, and so on. Further, it may be also governed by the damage of the head due to the friction caused by its contact with the paper or ink ribbon in the print heads of contact type, particularly, for the thermal recording or thermal transfer recording, or the clogging with the ink or contamination in the ink flow passage near the heat generating circuit in the ink jet recording system.
When part of the heat generating elements of the print head, in other words, the print segment, is broken by above factors, the information to be printed may be partially lacked, or the printed information may be recognized incorrectly, whereupon the replacement of the print head is required. However, the print head is an expensive element, while the labor for the replacement and the inoperative loss time required for the replacement may occur, thereby giving rise to the increase in the print cost.
To cover the above drawbacks, a proposal has been made as disclosed in Japanese Laid-Open Patent Application No. 61-104872, in which the electric current too small to effect printing is passed through the heat generating circuit of the print head to detect the disconnected portion, determining whether or not print data is present at the print position corresponding to its disconnected portion, in which if not present, the printing is directly made, or otherwise, the location without print data is searched in its neighborhood, and if such a location is present, the printing is made at that location. Or a method of representing the life of the thermal head as the recordable length, with an indication “THE DURABILITY OF THIS THERMAL HEAD IS ROUGHLY 50KM” has been taken to indicate the replacement time.
On the other hand, in conventional printers, because if the printing is performed irrespective of the amount of the serpentine or skew running of the print medium to be printed, the print quality may be degraded or the color aberration may occur in the color printer, the amount of serpentine or skew running is detected, and in excess of the set amount of serpentine or skew running, the operation is stopped as an abnormal conveyance, with an error indication on the screen to prompt the operator to reset or reinsert of the sheet.
However, regarding the life of the head, owing to the ruled line or frame contained in the print context, the number of conductions to a specific heat generating circuit within the print head increases, upon printing a number of sheets, so that the life of the heat generating circuit will determine the life of the whole of the print head, or even if the printing is performed by shifting the disconnected portion, the number of conductions to the specific heat generating circuit also increases, possibly resulting in a risk of causing a disconnection of the line.
Also, regarding the skew or serpentine running of the printing medium, the operation is stopped if the amount of skew or serpentine running is in excess of a certain value, and in the constitution of having the error indication, the set value for satisfying the print quality is smaller as the print context is more highly defined, resulting in a problem that if there occurs even a slight amount of skew or serpentine running, the printing is stopped due to the error detection, frequently necessitating the error release operation, or causing the useless consumption of the print medium.
The present invention has paid attention to specific problems with the label printer for performing the printing on the labels bonded on the release paper.
In the printer with the labels bonded in succession on the release paper as the printing medium, the labels of various shapes are selected in accordance with the print format or the quantity of information to be printed, and mounted on the printer. If the shape of the labels mounted does not accord with the print format, the printing may occur out of the label portion, resulting in the problem of contaminating the conveyance system, degrading the print quality, or shortening the life of the printer. Therefore, it is preferable to judge the shape of the labels inside the printer. A device for judging the shape of such labels has been described in, for example, Japanese Laid-Open Patent Application No. 58-194584. That is, the length of label in a lateral direction regulates one side of each of successive labels, in which a required number of detectors are disposed along a width direction near the other side to determine the length in the lateral direction in accordance with the signals from such detectors. The length of label in a longitudinal direction can be determined by a method of providing apertures indicating the print start in the labels to obtain the distance from the first aperture to the next
Fukushima Tatsuya
Harada Tsutomu
Inose Shigeru
Ishikawa Kohei
Iwasaki Shinichi
Barlow John
Canon Aptex Inc.
Fitzpatrick ,Cella, Harper & Scinto
Stewart Jr. Charles W.
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