JPS61195882A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To prevent an ink ribbon from being wasted and provide an inexpensive thermal transfer printer, by providing an ink ribbon trailing end detecting means on a substrate of a thermal head. CONSTITUTION:The ink ribbon trailing end detector is mounted on the substrate of the thermal head 6. Namely, a reflection-type photosensor comprising a light-emitting element 11 such as a LED and a light-receiving element 12 such as phototransistor is provided as the ink ribbon trailing end detector on the thermal head 6 on the downstream side of heating resistors 8 with respect to the moving direction of the ink ribbon 4. When the residual amount of the ribbon 4 is decreased and a trailing end part of the ribbon provided with a tinfoil or the like comes to the position of the head 6, the light from the light- emitting element 11 is reflected by the tinfoil to the light-receiving element 12 with a high reflectance, and an electric current is passed to an electrode 15 on the element 12 side.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a thermal transfer printer, and more particularly to a thermal transfer printer equipped with a thermal head and an ink ribbon supply means and a carriage that moves along recording paper. be.

[Prior Art] In this type of thermal transfer printer, a ribbon cassette containing an ink ribbon is usually mounted on a carriage, and recording is performed by a thermal head.

The structure of such a conventional ribbon cassette is shown in FIG.

That is, in FIG. 1, the reference numeral 1 indicates a cassette case, and the ink ribbon 4 is housed within this cassette case 1. In FIG.

The ink ribbon 4 is wound around the supply reel 3, and is passed through several guide bins la across an opening 5 provided in a part of the cassette case l, and then taken up by the take-up reel 2 as will be described later. It is wound up sequentially.

These supply reel 39 and take-up reel 2 are respectively fitted to reel shafts 3a and 2a which protrude into the cassette case 1 from through holes in the bottom surface of the cassette case 1 provided on the carriage side, which will be described later.

A reel shaft 2a to which the take-up reel 2 is fitted rotates in the direction in which the ink ribbon 4 is wound, that is, counterclockwise in FIG. 1, in synchronization with the recording speed. The reel shaft 3a is the ink ribbon 4
is wound up and rotates as the supply reel 3 rotates.

The reference numeral 6 indicates a thermal head provided on the carriage side, and the front surface of this thermal head 6 is the back surface of the ink ribbon 4 (the surface on which ink is not applied).
is inserted into the opening 5 so as to face each other.

FIG. 2 shows details of the thermal head 6.

That is, in FIG. 2, reference numeral 9 indicates a common electrode maintained at a constant potential VP, and reference numeral 10 indicates a plurality of individual electrodes.

These individual electrodes 10 are selectively grounded according to the recording command.
By lowering the voltage to the current level, a current is selectively applied to cause the resistor 8 connected between the heating individual electrode IO and the common electrode 9 to generate heat, thereby recording.

The heating resistor that generates heat thereby melts the ink on the ink ribbon 4 located in front of the thermal head 6 and transfers it to the recording paper.

On the other hand, in FIG. 1, the reference numeral 7 indicates an ink ribbon end detector, which is generally provided as a reflective photosensor.

In other words, a ribbon end is provided at the end of the ink ribbon 4 that has a different light reflectance from the ink-applied part, and by detecting this, it is detected that the ink ribbon has run out, and the recording operation is temporarily stopped and a new one is printed. Replace with ink ribbon.

By the way, the ink ribbon cassette as mentioned above is
It is detachably mounted on a carriage 16 as shown in the figure.

The carriage 16 is provided so as to be movable along a platen 18 around which a recording paper 17 is wound, and an endless belt 2 stretched between a pair of left and right pulleys 19 and 20.
It is fixed in the middle of 1.

Further, the carriage 16 is guided so as to move linearly in the horizontal direction by a guide shaft 24 suspended between the side plates 22 and 23 of the apparatus.

However, in the conventional thermal transfer printer configured as described above, the recording position, that is, the position of the thermal head 6 in FIG. If the recording operation were immediately stopped at this point, the ink ribbon 4 having a length corresponding to the distance between the thermal head 6 and the ink ribbon end detector 7 would be discarded unused, which would be wasteful.

Furthermore, since the thermal head 6 and the ink ribbon end detector 7 are separated from each other, they must be wired separately, which increases manufacturing costs and prevents miniaturization of the ribbon cassette.

[Objective] The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to eliminate waste of ink ribbons and provide an inexpensive thermal transfer printer.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIGS. 3 and 4 illustrate one embodiment of the present invention. In the figures, the same or corresponding parts as in FIGS. 1 and 2 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, an ink ribbon end detector is mounted on the substrate of the thermal head 6.

That is, as shown in FIG.
As an ink ribbon end detector, a reflective photosensor composed of
It is located near the front.

The reference numeral 13 is a common electrode of the reflective photosensor, and a constant potential Vs is applied thereto.

The reference numeral 14 is a light-emitting element side electrode in which a potential is maintained so that a constant current flows through the light-emitting element 11, and the reference numeral 15 is a light-receiving element-side electrode through which a current flows depending on the amount of light received by the light-receiving element 12. be.

If such a structure is adopted, there is no need to separately provide wiring for the thermal head 6 and the ink ribbon end detector.
The ribbon cassette can be extremely simplified as shown in FIG.

If silver paper or the like having a high reflectance is placed at the end of the ink ribbon 4, the end of the ink ribbon can be detected as follows.

That is, during normal recording, the light emitting element 11 irradiates the ink ribbon 4 traveling in the direction of arrow B in FIG. No current flows.

When a portion of the ink ribbon 4 has a small remaining amount and the end of the ink ribbon with silver paper etc. reaches the thermal head 6, the light from the light emitting element 11 hits this silver paper and is reflected to the light receiving element 12 with a high reflectance. , a current flows through the light-receiving element side electrode 15.

By detecting this current, it is detected that the remaining amount of the ink ribbon is exhausted, and if the recording operation is stopped at the same time, the ink ribbon will not be wasted, which is extremely convenient.

In addition, there is no need to provide a part of the cassette into which the end detection means of the ink ribbon is inserted, as in the conventional case, and there is no need to guide the ink ribbon to this part, so the entire cassette can be made smaller as shown in Figure 4. can be converted into

[Effect] As is clear from the following explanation, according to the present invention, a structure is adopted in which the end of the ink ribbon can be detected immediately before the heating element of the thermal head. It is possible to eliminate the waste of ink ribbons, eliminate the need to separately wire the thermal head and the ink ribbon end detector, and obtain a thermal transfer printer with a simple structure and low cost.

Furthermore, compared to a conventional structure in which an ink ribbon end detector is provided at a position away from the thermal head, the entire cassette can be made smaller.

[Brief explanation of drawings]

Figures 1 and 2 explain the conventional structure.
The figure is a cross-sectional plan view of a ribbon cassette, Figure 2 is a partially enlarged perspective view of a thermal head, Figures 3 and 4 are for explaining an embodiment of the present invention, and Figure 3 is a diagram of a thermal head. FIG. 4 is a cross-sectional plan view of the ribbon cassette, and FIG. 5 is a schematic configuration diagram of the thermal printer. 1... Cassette case 2 Take-up reel 3... Supply reel 4... Ink ribbon 6... Thermal head 8... Heating resistor 9... Common electrode
10... Individual electrode 11... Light emitting element
12... Light receiving element Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

Claims (1)

[Claims] A thermal transfer printer that is equipped with a thermal head and that performs recording by moving a carriage reciprocatingly along a platen on which an ink ribbon cassette is removably mounted, characterized in that an ink ribbon end detection means is provided on a substrate of the thermal head. Thermal transfer printer.