JPS61125877A - Ribbon end detector for thermal transfer printer - Google Patents

Abstract

PURPOSE:To enable a ribbon end to be detected irrespectively of whether the ribbon end is treated or of the method of treating the ribbon end, by providing a rotary conductor on a reel base for a take-up reel. CONSTITUTION:When a printing operation is started and a driving gear 24 is rotated, rotation of a take-up gear 17 is transmitted to the take-up reel base 15 through a slip plate 16, whereby an ink ribbon is taken up. As the amount of the ribbon 12 taken up is increased, surplus rotation is consumed in slippage of the slip plate 16 when the ribbon 12 is taken up. When the ink ribbon is remaining on the payout core side, the ribbon can be taken up by the take-up reel, so that the rotary conductor 19 is rotated, and a switch is repeatedly turned ON and OFF. When the ink ribbon on the payout core side runs out, the reel base 15 is not rotated, so that the switch is maintained in an ON state or an OFF state, which is detected by an electric circuit or a program in a microcomputer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a ribbon printer for a thermal transfer printer that can transfer ink from a thermal transfer ink ribbon onto plain paper by heating a thermal head to form characters, etc. This relates to the output device.

Conventional configurations and their problems In recent years, thermal transfer printers are printers that do not emit noise like wire dot printers, and can print on plain paper rather than special paper like thermal paper.
It is being used mainly in the field of OAI equipment. However, since the ink ribbon has a finite length and printing is impossible at the end of the ink ribbon, a means for detecting the end of the ribbon is required.

Hereinafter, a conventional ribbon end detection device will be explained based on FIG. 1 is an ink ribbon supply core, 2 is a take-up core, and 3 is an ink ribbon.

The two-point slK line indicates the state at the beginning of printing. ink ribbon 4
After the paper 3 comes out of the preparation core 1, it passes through two guide pins 4.4, passes between the heating head 5 and the recording paper 6, and is wound up by the winding core 2. 7 is a reflective or transmissive optical sensor.

The operation of the ribbon end detection device configured as shown in F will be described below. As shown by the two-dot chain line in FIG. 1, when the ink ribbon 3 is wound around the supply core 1, the ink ribbon 3 faces the optical sensor 7.
Since ink is applied to the area, the reflective optical sensor does not reflect light, and the transmissive optical sensor does not transmit light, so it can be determined that printing is still possible. When a printing operation is performed and the ink ribbon 3 is no longer in the supply core 1 as shown by the solid line, a reflective material is applied to the ink ribbon 3 facing the optical sensor 7 when an anti-tI4 type optical sensor is used. If the ink ribbon 3 facing the optical sensor 7 is made transparent when a transmission type optical sensor is used, the end of the ink ribbon 3 can be detected and the printing operation can be stopped. do.

However, in the above configuration, there is a close relationship between the type of optical sensor and the ink ribbon termination process, and detection is impossible if the combination is different. Also, no matter which optical sensor is selected, there is a problem that there is a high risk of ink particles or paper dust adhering to the light emitting surface or the light receiving surface.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and it is an object of the present invention to provide a ribbon end detection device that is less likely to malfunction regardless of the method used to treat the end of the ink ribbon.

Structure of the Invention In order to achieve the above object, the ribbon end detection device for a thermal transfer printer of the present invention includes a take-up reel head that engages with a take-up core having a plurality of protrusions on the inner surface, and a ribbon end detection device that is press-fitted into the take-up reel head. a reel stand rotatable around a reel shaft; a take-up gear rotatable around the reel stand; a slip plate sandwiched between the pedestal of the reel stand and the take-up gear; The take-up reel section is formed by a coil spring that biases the take-up gear toward the base of the reel base through a slip plate, and a rotating conductor made of a conductive material and having a plurality of protrusions and attached to the reel base. and a switch section having a pair of contacts that come into contact with the rotating conductor. DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings (FIGS. 1 to 4).

In the figure, reference numeral 11 denotes a winding core, around which a used ink ribbon 12 is wound, and which has a plurality of protrusions 13 on its inner surface. 14 is a take-up reel head that engages with the take-up core 11. Reference numeral 15 denotes a take-up reel stand, and the take-up reel head 14 is externally crimped onto the upper end of the take-up reel head 14.
A slip plate 16, a winding gear 11, and a coil spring 18 are assembled between the pedestal 15a at the lower end of the holder 5 and the pedestal 15a. A rotary base 20 is press-fitted below the base 15a of the take-up reel base 15 and holds a rotating conductor 19 made of a conductive material and having a plurality of protrusions. Next to the rotating conductor 19 is a switch section having two contact hands 21i, 22 is a switch board thereof, and 23 is a switch base. A drive gear 24 rotates the winding gear 17, and is integrated with the drive shaft 25. A lower board 26 pivotally supports the drive gear shaft 25 and the reel shaft 21 of the reel stand 15. 28 is an upper substrate.

The operation of the ribbon end detection device of this embodiment configured as described above will be described below.

First, the drive gear 24 rotates in one direction only when printing, and does not rotate during other operations. now,
When the printing operation begins and the drive gear 24 rotates, the take-up gear 17 rotates in the opposite direction. Due to the pressure of the coil spring 1Q1B, the winding gear 17, the slip plate 16, and the slip plate 16
Since a frictional force is acting on the base 15a, the rotation of the take-up gear 17 is caused by the rotation of the take-up reel base 1 via the slip plate 16.
5, the take-up reel head 14 also rotates, and the result is! The winding core 11 rotates and the ink ribbon 12 is wound up. When the number of ink ribbons 12 wound around the take-up core 11 is small, as shown in FIG. is gradually decreasing. However, the rotation speed of the drive gear 24 is the same. Therefore, the slip plate 16 absorbs this difference, and the excess rotation of the winding gear 17 is caused to slip and disappear at this portion. When there is an ink ribbon on the supply core side, it can be taken up with the take-up reel.
The rotating conductor 19 rotates. The state of the switch at this time is shown in FIG. When the ink ribbon on the supply core side runs out, it becomes impossible to wind it up with the take-up reel. At this time, the take-up gear 17 is rotating, but the take-up reel stand 1
5 is not rotating. FIG. 4 shows the state of the switch near the end of the ink ribbon. In this way, when the end of the ribbon is reached, the switch remains on or off, so this can be easily detected by monitoring it using an electric circuit or a microcomputer program. Incidentally, in the description of the above embodiment, the rotating conductor 19 is held on the rotating base 20 and then press-fitted into the take-up reel stand 15; By doing so, it is possible to reduce the number of parts.

Effects of the Invention As described above, the present invention includes a rotating conductor provided on the reel stand of the take-up reel, and a switch section for detecting the rotation of the rotating conductor. It is possible to detect the ribbon end regardless of whether or not the ink ribbon is terminated, and the rotating conductor and contactor that serve as the switch are always sliding, so they are cleaned and there is no possibility of contact failure. The possibility of malfunction is low, and the ribbon end detection section does not require maintenance over a long period of time.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a sectional view of the ribbon end detection device, Figure 2 being a plan view of the switch section, and Figures 3 and 4 showing the state of the switch. Explanatory diagram, 5th
The figure is a plan view of a conventional example. 11... Winding core, 12... Ink ribbon, 13.
...Protrusion, 14... Take-up reel head, 15... Take-up reel stand, 16... Slip plate, 11... Take-up gear, 18-... Coil spring, 19°°° rotation conductive Body 2
0°°° rotating pedestal, 21-°° contactor, 22°”
1 switch board, 23... switch stand, 24...
Drive gear, 27... Reel shaft Fig. 1 Fig. 2 2'? Figure 3

Claims (1)

[Claims] 1. A take-up reel head that engages with a take-up core that has multiple protrusions on its inner surface, a reel stand that is press-fitted into this take-up reel head and is rotatable around a reel shaft, and a reel that rotates around this reel stand. a take-up gear, a slip plate sandwiched between the pedestal of the reel stand and the take-up gear, and a coil spring that urges the take-up gear toward the pedestal of the reel stand via the slip plate. , a take-up reel part is constituted by a rotating conductor made of a conductive material and having a plurality of protrusions and attached to the reel stand, and a switch part is provided having a pair of contacts that come into contact with the rotary conductor. Ribbon end detection device for thermal transfer printers.