JPH0630454Y2 - Ribbon end detection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a ribbon end detection mechanism for detecting that an ink ribbon or the like of a printer has been fed from the reel to the end, and is particularly used for a thermal printer. The present invention relates to a ribbon end detection mechanism for detecting the end portion of a thermal ribbon.

[Conventional technology]

Conventionally, this type of ribbon end detection mechanism has a tape such as silver tape that easily reflects light attached to the end of the thermal ribbon, and a reflection type sensor that detects light reflection mounted on the carriage mechanism of the thermal printer. The ribbon end is detected by discriminating the ink application part and the tape at the end of the ribbon.

[Problems to be solved by the invention]

Since the conventional ribbon end detection mechanism described above uses a reflection type sensor as a detector, when the color ribbon is used, the amount of light reflected from the ribbon changes due to the color change of the ribbon and the reflection type sensor malfunctions. There is a drawback that there is.

[Means for solving problems]

The present invention provides a ribbon end detection mechanism for detecting that a ribbon, which has one end fixed to a ribbon supply reel and is wound around, is fed out from the other end side to the one end. A reel guide that is pushed and bent by the ribbon supply reel when the inner surface slides and the ribbon is paid out to the one end, and a leaf spring-shaped first member that is pushed and bent when the reel guide bends. Electrode, a second electrode that comes into electrical contact with each other when the first electrode is bent, and a conduction detector that detects conduction between the first and second electrodes. To be done.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

1 to 4 are plan views of an embodiment of the present invention (the upper side plate of the ribbon cassette 13 is omitted).
FIG. 5 is a front view, a side view in which a part thereof is cut away, and a detailed view of an A portion, and FIGS. 5 to 8 are views showing an operation principle.

First, referring to FIG. 1, a ribbon cassette 13 is mounted on a ribbon guide 12 of a thermal printer having a thermal head 5 and leaf spring-shaped electrodes 10 and 11. At that time, the leaf spring-shaped electrodes 10 and 11 enter between the reel guides 8 and 9 in the ribbon cassette 13. The reel guide 9 has a fixed end on a side plate of the ribbon cassette 13, but has a notch 14 so that it is flexible.

The thermal ribbon 1 is wound on a ribbon supply reel 2 slidably attached to reel guides 8 and 9. Further, the thermal ribbon 1 passes from the ribbon supply reel 2 through the back tension spring 3 and the idle roller R4 provided in the ribbon cassette 13, and further passes through the thermal head 5 and the idle roller L6 provided in the ribbon cassette 13. One end is fixed to the winding shaft 7.

Reference is now made to FIGS. 5 and 7 which are plan views showing only the thermal ribbon 1 and its periphery, and FIGS. 6 and 8 which are sectional views of a portion of the ribbon supply reel 2. FIG. 5 and FIG. 6 show the winding start state of the thermal ribbon 1,
7 and 8 show the state at the end of winding.

First, the thermal ribbon 1 wound around the ribbon supply reel 2 is gradually wound around the winding shaft 7 as the winding shaft 7 rotates. In this state, the reel guide 9
The spring-extracted state electrodes 10 and 11 are separated from each other.
When the thermal ribbon 1 is wound up to the end, the other end of the ribbon 1 is fixed to the ribbon supply reel 2. Therefore, as shown in FIG. 7 and FIG. As a result, the ribbon supply reel 2 is pulled downward, and the flexible shell-shaped reel guide 9 supporting the ribbon supply reel 2 is also pushed downward by the ribbon supply reel 2 to bend downward, and the leaf spring electrode 10 is also included. It is pushed by and contacts the other electrode 11 to conduct electricity. This electrode 10,
The ribbon end of the thermal ribbon 1 can be detected by detecting the conduction of 11.

[Effect of device]

As described above, according to the present invention, the contact point switch is constituted by the plate-spring-shaped electrode that is moved by the reel guide of the ribbon supply reel, so that even if the amount of reflected light changes due to discoloration of the ribbon or the like, no malfunction occurs, and a simple The mechanism has the effect of detecting the ribbon end at low cost.

[Brief description of drawings]

1 to 4 are plan views of an embodiment of the present invention (the upper side plate of the ribbon cassette 13 is omitted).
FIG. 5 and FIG. 6 are respectively a plan view and a ribbon supply showing only the thermal ribbon 1 in the winding start state of the thermal ribbon 1 and its peripheral portion. 7 and 8 are a plan view showing only the thermal ribbon 1 and its peripheral portion in a state where the thermal ribbon 1 is wound, and a sectional view of the ribbon supply reel 2 respectively. . 1 ... Thermal ribbon, 2 ... Ribbon supply reel, 3 ...
Back tension spring, 4 idle roller R, 5 thermal head, 6 idle roller L,
7 ... Winding shaft, 8 ... Reel guide, 9 ... Shell-shaped reel guide, 10 ... Leaf spring electrode, 11 ... Leaf spring electrode, 12 ... Ribbon guide, 13 ... Ribbon cassette.

Claims (1)

[Scope of utility model registration request] 1. A ribbon end detection mechanism for detecting that a ribbon having one end fixed to a ribbon supply reel and wound around the ribbon supply reel is fed from the other end side to the one end. A reel guide that is pushed and bent by the ribbon supply reel when the inner surface of the reel slides and the ribbon is fed to the one end, and a leaf spring-shaped first guide that is pushed and bent when the reel guide bends. A first electrode, a second electrode that is in contact with the first electrode when the first electrode is bent, and is electrically connected to each other;
And a conduction detecting section for detecting conduction of the second electrode, the ribbon end detecting mechanism.