JPH0436874B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for preventing ink ribbon slack in a thermal transfer printer, and in particular, after the final printing in a printing line,
This invention relates to a method of preventing ink ribbon slack by slightly overrunning the thermal print head.

(b) Background of the technology A thermal transfer printer has a rotatable platen that guides printing paper, and a plurality of heating elements placed on a carriage that is movable in the axial direction of the platen in opposition to the platen. The thermal printing head, which has a heating element that selectively generates heat based on a printing signal, is pressed against the printing paper via an ink ribbon coated with a layer of heat-melting ink, and the ink ribbon is heated. It is a non-impact printer that locally melts the meltable ink layer and transfers the melted ink to printing paper.Compared to inkjet printers, etc., it has a simpler mechanism and is easier to maintain.It is also a thermal printer that uses thermal paper. Unlike printers, it can use plain paper, so it is widely used in printers such as word processors, TSS terminals, and ticket issuing machines.

(c) Prior art and problems By the way, in the above-mentioned conventional thermal transfer printer, an ink ribbon and a thermal print head are placed on the carriage, and in the printing state, the thermal print head advances toward the platen to release ink. Since the ribbon is pressed against the printing paper, the ink ribbon is wound up one after another as the carriage moves. On the other hand, when the carriage returns, the thermal printing head moves back slightly and returns without pressing the ink ribbon, so that the ink ribbon becomes free and winding is interrupted.

Therefore, when the ink ribbon attached to the print paper is peeled off when the carriage is returned to the home position after the final printing, the ink ribbon is pulled out from the ribbon cassette by the adhesion force of the ink, causing the ink ribbon to become loose. Also, if the used ink ribbon that has already been wound up is pulled out from the winding section due to the advance of the head at the time of starting printing after the carriage returns, the ink ribbon may become loose when starting to print. There was an inconvenience that printing defects were caused by the slack.

(d) Purpose of the invention In order to eliminate the above-mentioned conventional drawbacks, the present invention has the following objectives:
Each time a line of printing is completed, the carriage on which the thermal print head is placed is moved a few more times without printing to eliminate the slack in the ink ribbon, and then returned to the home position to remove the ink ribbon. An object of the present invention is to provide a novel method for preventing ink ribbon from loosening in a thermal transfer printer, which improves print quality.

(e) Structure of the Invention According to the present invention, the present invention comprises a platen for guiding printing paper, and a thermal printing head mounted on a carriage facing the platen and movable along the surface of the platen. A thermal transfer type in which the ink ribbon is pressed against the printing paper by the printing head, and the heating element of the thermal printing head selectively generates heat based on the printing signal to transfer the ink of the ink ribbon to the printing paper. In the printer, after the last character of the printing line is printed, the thermal printing head is moved a predetermined distance in the printing direction while the thermal printing head is in pressure contact with the ink ribbon and the heating element does not generate heat. This is achieved by providing a method for preventing loosening of an ink ribbon in a thermal transfer printer, characterized in that the pressure contact of the ink ribbon is released.

(f) Embodiments of the invention Examples of the invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of an ink ribbon loosening prevention mechanism of a printer according to the present invention. In the figure, 1 is a rotatable platen that guides the printing paper 7, 2 is a thermal printing head, and 3 is an ink ribbon cassette. It is mounted on a carriage 5 movable along an axis 6. Then, the moving range A of the carriage 5 on which the thermal printing head 2 is placed with respect to the platen 1 side is divided into the printing area B and the printing area B.
A configuration is adopted in which the ink ribbon is divided into a non-printing area C for eliminating slack, which is moved to a predetermined non-printing area from the end of the printing line.

Therefore, as shown in FIG. 2, the print control circuit 21 sends a carriage drive signal to the driver 22, and the lateral feed servo motor 23 for driving the guide shaft 6 drives the carriage 5 in the printing direction relative to the platen 1. The thermal print head 2 is driven by the print signal to perform a predetermined printing operation. When the carriage 5 moves from the end of the print line in the print area B to the non-print area C, the print control circuit 21 prohibits the thermal print head 2 from performing a print operation. Furthermore, the ink ribbon 4 is wound up even while the carriage 5 moves through the non-print area C in a non-printing state. Therefore, the unused ink ribbon 4 is in contact with the thermal printing head 2. Thereafter, at the end of the non-print area C, the thermal print head 2 is slightly retreated (separated) and returns to the carriage. By controlling as described above, in the non-printing area C, the ink ribbon 4
Since the ink does not melt, the ink ribbon 4 can be easily pulled off from the printing paper 7. Furthermore, even if the printing head 2 moves forward at the start of the next printing after the carriage returns, the used ink ribbon 4 will not be pulled out as in the conventional example.

The length of the above-mentioned non-printing area C is such that the temperature of the heating element of the thermal printing head 2 decreases to such an extent that the ink of the ink ribbon 4 does not melt after the final printing.

(g) Effects of the Invention As is clear from the above explanation, the method for preventing ink ribbon slack in a thermal transfer printer according to the present invention prevents loosening of ink ribbon from occurring during printing operations with a simple configuration without major changes to the structure of the device. This method has the excellent advantage of being able to eliminate slack in the ink ribbon at each printing line feed, and has great practical effects such as preventing printing defects and improving printing quality. Therefore, it is extremely advantageous when applied to various thermal transfer printers.

[Brief explanation of drawings]

FIG. 1 is a plan view of essential parts for explaining an embodiment of the method for preventing loosening of an ink ribbon for a thermal transfer printer according to the present invention, and FIG. 2 is a block diagram for explaining the method for preventing loosening of an ink ribbon in conjunction with FIG. 1. It is. In the drawing, 1 is a platen, 2 is a thermal print head, 3 is an ink ribbon cassette, 3a is a ribbon winding section, 4 is an ink ribbon, 5 is a carriage, 6 is a guide shaft, 7 is a printing paper, 21 is a print control circuit, 22 is a driver, 23 is a lateral feed servo motor, A is a movement range of the carriage 5, B is a printing area, and C is a non-printing area.

Claims (1)

[Scope of Claims] 1. A printer comprising a platen 1 that guides a printing paper 7, and a thermal printing head 2 placed on a carriage 5 facing the platen 1 and movable along the surface of the platen 1, The printing head 2 presses the ink ribbon 4 against the printing paper 7, and selectively causes the heating element of the thermal printing head 2 to generate heat based on the printing signal, thereby transferring the ink on the ink ribbon 4 to the printing paper 7. In a thermal transfer printer, after printing the last character of a printing line, the thermal printing head 2 is moved a predetermined distance in the printing direction in a state in which the thermal printing head 2 is brought into pressure contact with the ink ribbon 4 and its heating element does not generate heat; The thermal printing head 2
A method for preventing loosening of an ink ribbon in a thermal transfer printer, characterized in that the pressure contact of the ink ribbon is released.