JPH038275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to the structure of a ribbon cassette, and in particular,
A ribbon that is replaceably mounted on a carriage that moves along the paper, feeds the ribbon through a head opening that receives a print head, and has a detection opening that receives a photoelectric ribbon end detector provided on the carriage. This invention relates to improvements in the structure of cassettes.

[Prior art]

2. Description of the Related Art In typewriters, printers, and the like, printing is performed by feeding an ink ribbon between a printing head and paper. In this case, a ribbon cassette is used for supplying the ink ribbon, which ribbon cassette is usually replaceably mounted on a carriage that moves along the paper with the print head. The ribbon cassette has a supply reel and a take-up reel rotatably provided therein, and a head opening for receiving a print head at the front end. In this way, the ink ribbon on the supply reel passes through the head opening by rotating the take-up reel at a predetermined speed (a speed corresponding to the moving speed of the printing head) with the take-up drive shaft provided on the carriage. Sent.

However, with this type of ribbon cassette, if you continue printing without knowing that the ink ribbon has run out, the desired print may not be output on the paper even though you are inputting information. Therefore, it is necessary to detect the end position of the ink ribbon by some method and stop the printing operation based on the detection signal.

This type of ribbon end detection device connects a tape made of a highly reflective material such as silver paper to the end of an ink ribbon (almost non-reflective), and uses a photoelectric ribbon end detection unit consisting of a light emitting diode and a phototransistor to detect the ink ribbon. A method is adopted in which the passage of the connecting portion between the tape and a highly reflective tape such as silver paper is detected. In this case, the photoelectric ribbon end detector is usually installed on the carriage and is configured to be visible at a position adjacent to the ribbon through a detection port formed in the cassette case.

However, in conventional ribbon cassettes of this type, the photoelectric ribbon end detector (photo sensor) was placed relatively close to the head opening on the upstream side of the ribbon feed. The length of the ribbon between the detection section and the printing section is short, and therefore, the structure is such that printing becomes impossible within a short time after the ribbon end is detected.

Therefore, as shown in FIG.
If the end of the ribbon is detected while printing a line of length l in the two arrow directions, printing cannot be continued until the end of the line (Z), and printing is stopped in the middle of the line and the ribbon cassette is removed. It was necessary to replace it. In other words, even if the ribbon end is detected in the middle of a line, it is not possible to reliably print to the end of that line, and only after replacing the ribbon cassette in the middle of the line can the end of the line be printed. I couldn't do it.

In this way, printing is stopped in the middle of a line, the ribbon cassette is replaced, and printing is restarted. For example, when printing up to the letter H in Figure 1 and replacing the ribbon cassette, the first character I to be printed after replacement is However, this method has the disadvantage that the printing position may be deviated due to errors in the mounting position of the ribbon cassette or the structure of the ribbon cassette itself.

In order to prevent the printing position from shifting, there is also a method of returning the printing head to the home position once when replacing the ribbon cassette, then feeding it to the inspection position (the position of the letter H), and then starting printing. However, with this method, the memory required to detect the stop position and to store the distance (positional relationship) between the detected position and the home position increases, and the control becomes complicated, making control difficult and operation difficult. The problem is that it takes a lot of time. In particular, control becomes extremely complicated when one line of data is received and printed at once.

〔the purpose〕

An object of the present invention is to eliminate the drawbacks of the conventional ribbon end detection means, to be able to reliably continue printing until the end of the line even after the ribbon end has been detected, and to prevent printing position deviation. To provide a ribbon cassette that can reliably prevent such damage.

A feature of the present invention is to achieve the above object by ensuring the distance along the ink ribbon path from the position corresponding to the print head to the position corresponding to the detection port at least as long as the movement width of the print head. be.

[Explanation of Examples]

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, a supply reel 2 and a take-up reel 3 are each rotatably supported in a ribbon cassette case (cassette case) 1, and the ink ribbon 4 moves the take-up reel 3 at a speed corresponding to the printing speed. By driving it, it is wound onto the take-up reel. A head opening 6 is formed in the front surface of the cassette case 1, that is, the part that receives the print head 5, and the ink ribbon 4 is passed through the head opening 6 so as to pass between the print head 5 and paper (not shown). Sent.

For example, as shown in FIG. 2, the ink ribbon 4 is guided by a desired number of guide pins 7 that are integrally formed and placed at desired positions on the bottom surface of the cassette case 1, thereby guiding it along a desired path. It is then sent from the supply reel 2 through the head opening 6 to the take-up reel 3.

As shown in FIGS. 2 and 3, a detection port 10 is formed at the bottom of the cassette case 1 to receive light from a photoelectric ribbon end detector 9 provided on the carriage 8. It is designed to detect the ribbon end of the ink ribbon. This ribbon end detector is composed of, for example, a light emitting diode (LED) 11 and a phototransistor (light receiving element) 12, and the light emitted from the light emitting diode 11 is reflected on a tape surface and the phototransistor 12 receives the light from the reflection port. The end position of the ink ribbon is detected by outputting an electrical signal and detecting the difference in reflectance between the ink ribbon and a highly reflective tape such as silver paper provided at the end of the ribbon.

According to the present invention, the position from the position corresponding to the print head 5 in the head opening 6 to the position corresponding to the detection port 10 (ribbon end detection position)
The distance along the ink ribbon feeding path is selected to be equal to or slightly larger than the moving width of the printing head 5 in a printer or the like.
The moving width of the printing head 5 means the moving distance of the head from its home position (the left end position in FIG. 1) to the other end, and is generally larger than the line length l in FIG. 1, and is at least The width of movement of the print head, which has a value equal to this, is constant depending on the printer, but the width of the paper used for this or the length of the line on the paper can be changed as necessary. By ensuring that the distance along the ink ribbon path from the position corresponding to the print head to the position corresponding to the detection port is at least equal to the movement width of the print head, the ribbon end can be continuously detected even in these various usage conditions. It is configured to ensure printing up to the end of the line.

According to the embodiment described above, when the ribbon end is detected, it is possible to reliably continue printing until the end of the line under any condition, and then replace the ribbon (replace the ribbon cassette). Therefore, it is possible to reliably prevent the printing position from shifting, and it is possible to output printed matter printed in an accurate predetermined arrangement.

Generally, it takes one row of data and converts it into one
In many cases, a printing method that prints at once is used,
Even in such a case, there is no need to stop the print head midway, and it is therefore possible to eliminate the complicated control required in the prior art, which takes into consideration such things as memorizing the print head stop position and preventing double printing.

In the present invention, the distance along the ink ribbon path from the position corresponding to the print head to the position corresponding to the detection port is set to be equal to or slightly larger than the width of movement of the print head. From the viewpoint of

Thermal transfer printers use a non-reusable (disposable) ink ribbon with an ink layer formed on a polyester sheet or capacitor paper, while wire dot printers use a ribbon impregnated with ink that can be recycled or reused. A usable ink ribbon is being used. Therefore, although the ribbon cassette of the present invention is particularly suitable for use in thermal transfer printers, it can also be used in wire dot printers, and can be applied to various types of printers that use ink ribbons. It is possible to implement the same method for .

〔effect〕

As is clear from the above description, the present invention provides a ribbon cassette that can reliably prevent misalignment of printing positions.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram illustrating the state of misalignment of the printing position that occurs when the ribbon cassette is replaced during printing, and Fig. 2 shows an embodiment of the ribbon cassette according to the present invention with the lid of the cassette case removed. The plan view and FIG. 3 are partial longitudinal cross-sectional views taken along the line - in FIG. 1...Cassette case, 2...Supply reel, 3
...Take-up reel, 4...Ink ribbon, 5...
Print head, 6... Head opening, 8... Carriage, 9... Ribbon end detector, 10... Detection port.

Claims (1)

[Claims] 1. Ribbon is fed through a head opening that is replaceably mounted on a carriage that moves along the paper and receives a print head, and a detection port is formed to receive a photoelectric ribbon end detector provided on the carriage. A ribbon cassette characterized in that the distance along the ink ribbon path from the position corresponding to the print head to the position corresponding to the detection port is equal to or larger than the width of movement of the print head.