JPH046932Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention particularly relates to a printer ribbon end detection mechanism that can detect with a simple mechanism that the ink ribbon of a serial printer has been fed to the end.

[Prior art and its problems]

Generally, in serial printers, the ink ribbon is fed out from the ribbon cassette to perform predetermined printing, but when the ribbon is fed out to the end, this is detected and the printing operation is paused and the ribbon cassette is replaced. It is necessary to do it.

An example of a conventional mechanism for detecting the end of a ribbon is shown in FIG. In the figure, a ribbon feeding rotary core 1 in a ribbon cassette (not shown) rotates in the direction of the arrow, and feeds out the ribbon 2 wound around it to a printing position. Reference numeral 3 is a ribbon end detection switch, which is placed in a position to sandwich the ribbon 2, and when the ribbon 2 is fed out to the end,
The end of the ribbon was detected by detecting a conductive lead tape portion 4 made of aluminum or the like especially provided at the end of the ribbon 2 using a high frequency electromagnetic method or the like.

However, this has the disadvantage that the ribbon end detection switch 3 itself is expensive.

Other conventional examples include those shown in FIGS. 2A and 2B. In the figure, reference numeral 5 denotes a ribbon cassette, which has a rotating core 6 for winding up the ribbon in addition to the rotating core 1 for feeding out the ribbon. The core 1 has a pair of axial notch grooves 1
It has a. 7 is a feeler-like movable piece, as shown in Fig. 2B.
It has a cam part 7a as shown in FIG.
It is guided by a pin 8 and is movable up and down, and is biased upward by a spring 9. When the ribbon 2 is wound around the core 1 one turn or more, the upper end of the movable piece 7 is in contact with the lower surface of the core 1 or the lower end of the ribbon 2 in the notched groove 1a. Reference numeral 10 denotes a micro switch, which is arranged opposite to the movable piece 7.

Here, when the ribbon 2 is fed out to the end, the movable piece 7 is moved upward to the position shown by the dotted line in the middle of FIG. Therefore, the cam portion 7a is the micro switch 10.
Press to change the switch and detect the ribbon end.

However, although this method is cheaper than the one shown in FIG. However, the biasing spring 9 must be specially provided, and the number of parts increases, making manufacturing and assembly troublesome.

[Purpose of invention]

In this invention, the movable piece, fixed contact, and movable contact are all arranged on the switch frame to form a unit-like structure, and the movable piece is guided by the switch frame, and the movable contact also plays the role of urging the movable piece. It is an object of the present invention to provide a ribbon end detection mechanism for a printer that has a small number of parts, is easy to adjust, and eliminates the above-mentioned drawbacks.

[Structure of the idea]

To this end, the configuration of the present invention includes a switch frame, a fixed contact provided on the switch frame, an elastically deformable movable contact provided on the switch frame so as to be able to come into contact with and separate from the fixed contact, and a movable contact that is guided through the switch frame. The movable piece is provided so as to be able to reciprocate freely, one end inside the frame abuts against a predetermined part of the movable contact, and one end of the movable piece outside the frame has a notch in the outer periphery due to the elasticity of the movable contact. The fixed contact is biased into contact with the boundary between the outer periphery of the rotating core around which the ribbon is wound on the ribbon supply side and the wound ribbon, and the fixed contact is elastically deformed by the movable contact. A pair of movable pieces are provided facing each other at positions sandwiching the movable contact in the direction, and the movable pieces are displaced in one direction and the opposite direction, respectively, when the ribbon is fed out to the end under no load and vice versa when overloaded. The above-mentioned no-load or overload is detected by selectively contacting and conducting the pair of fixed contacts.

〔Example〕

3 and 4 are a perspective view and a vertical sectional view, respectively, of an example of a ribbon end detection switch to which an embodiment of the printer ribbon end detection mechanism of the present invention is applied.

In the figure, the ribbon end detection switch 11 includes a switch frame 12, a fixed contact 13, and a movable contact 1.
4, the movable piece 15.

The switch frame 12 is made of resin, has a box shape, and has a through guide hole 12a.

The fixed contact 13 has a pair of fixed contact parts 13 on both upper and lower inner sides of a U-shaped part 13a provided at the tip of the metal plate.
b, 13c, and is fixed inside the switch frame 12.

The movable contact 14 is made of an elastically deformable metal plate, and is located inside the switch frame 12 as shown in FIG.
It is fixedly installed in elastic contact with the upper fixed contact portion 13b, and constitutes a so-called leaf switch.

The movable piece 15 is made of resin or the like, and has a convex portion 15 at the upper end.
a and a lower end convex portion 15b for retaining the switch frame 12, and is disposed so as to be movable in a vertical direction guidingly through the guide hole 12a of the switch frame 12, and its lower end abuts against the movable contact 14. A coil spring 16 is wound around a portion of the movable piece 15 that protrudes from the switch frame 12. Note that this spring 16 may be omitted.

This ribbon end detection switch 11 is arranged below the ribbon feeding rotary core 1 (see FIGS. 2A, B and 5B) inside a ribbon cassette (not shown). The core 1 has a notched groove 1 as shown in Fig. 2A.
Assume that it has a. At this time, the movable piece 15 in FIG.
It is set by being pushed down a predetermined amount against the urging force of. Therefore, in Figure B, the movable contact 14 is elastically deformed downward and separated from the upper fixed contact portion 13b. Therefore, the detection switch 11 is in a state in which it cannot output a detection signal.

Next, the operation of the detection switch 11 will be explained. While ribbon 2 is being fed out, Figure 5B
state is maintained and the ribbon end is not detected. Subsequently, when the ribbon 2 is fed out to the end, the ribbon 2 wound around the core 1 disappears. Therefore, as shown in FIG. 5A, the movable piece 15 moves upward and enters the notch groove 1a of the core 1 due to the urging force caused by the elastic deformation of the spring 16 and the movable contact 14. Therefore, as shown in FIG.
It is detected that the ribbon has been fed to the end.

Next, as shown in FIG. 5C, the ribbon 2 and the movable piece 15 are
For some reason, a foreign object of a specified thickness or more is found between the
7 is caught, the movable piece 15 is further pushed down from the initial set state against the spring 16 and the movable contact 14. Therefore, the movable contact 14 in FIG. 3C comes into contact with the lower fixed contact portion 13c, and this abnormal state is regarded as an end-feeding state of the ribbon and is determined and detected.

According to the detection switch 11, the switch frame 12 is provided with a leaf switch including a fixed contact 13 and a movable contact 14, and the movable piece 15 is only provided to make the whole unit like a unit.
Since the guide is performed by the switch frame 12 and the movable piece 15 is biased by the movable contact 14, the number of parts is small and the configuration is simple.

In the above embodiment, the movable piece 15 enters into the notch groove 1a of the core 1, but the present invention is not limited to this, and as long as the ribbon 2 is completely wound around the ribbon winding core, the ribbon The lower end of the ribbon 2 may be brought into contact with the lower end of the ribbon 2 in the middle of the running path of the ribbon 2.

FIG. 6 is a perspective view of essential parts of another embodiment of the detection switch. In the figure, the fixed contact 13-1 of the detection switch 21 has three fixed contact parts 13b and 13c on both the upper and lower inner sides of the U-shaped part 13a, and correspondingly, a movable contact 14-1 as well. Three movable contact portions 14a are branched. According to this, the ribbon end can be detected only by having at least one of the three movable contact parts 14a contact one of the three fixed contact parts 13b or 13c, and the switch function can be performed. Safety can be increased.

[Effect of idea]

As explained above, according to the printer ribbon end detection mechanism of the present invention, the movable piece, fixed contact, and movable contact are arranged together on the switch frame to form a unit, and the guide of the movable piece is guided by the switch frame. Since the movable contact also serves as a force for the movable piece, the overall configuration is made into a unit, making handling and assembly adjustment easy. Furthermore, the number of parts is reduced, simplifying the configuration and further improving This has the advantage of facilitating assembly and reducing costs.

Moreover, since the fixed contacts of the present invention are provided in a pair opposite to each other in the direction of elastic deformation of the movable contact at positions sandwiching the movable contact, the movable piece can be used without a ribbon and when detecting incorrect insertion of the cassette. It has the effect of producing a signal similar to ribbon end detection when pressed excessively.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional example of a ribbon end detection mechanism of a printer, and FIGS. 2A and 2B are plan views of a ribbon cassette to which other conventional examples of the above detection mechanism are applied, and 3 and 4 are a perspective view and a vertical cross-sectional view of an example of a ribbon end detection switch to which an embodiment of the printer ribbon end detection mechanism of the present invention is applied, respectively. 5A to 5C are diagrams showing the operating procedure of the main parts of the detection switch, respectively, and FIG. 6 is a perspective view of the main parts of another embodiment of the detection switch. 1, 6... Rotating core, 1a... Notch groove, 2...
Ribbon, 3...Detection switch, 4...Lead tape portion, 5...Ribbon cassette, 7, 15...Movable piece, 10...Micro switch, 11, 21...
...Ribbon end detection switch, 12...Switch frame, 12a...Guide hole, 13, 13-1
...Fixed contact, 13b, 13c...Fixed contact part,
14...Movable contact, 14a...Movable contact portion, 17
...Foreign object.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A switch frame, a fixed contact provided on the switch frame, an elastically deformable movable contact provided on the switch frame so as to be able to come into contact with and separate from the fixed contact, and a movable contact that is guided through the switch frame. The movable piece is provided so as to be able to reciprocate freely, and one end inside the frame is abutted against a predetermined portion of the movable contact, and one end of the movable piece outside the frame has a notch in the outer periphery due to the elasticity of the movable contact. The fixed contact is biased against the boundary between the outer periphery of the rotating core around which the ribbon on the ribbon supply side is wound and the wound ribbon, and the fixed contact is biased against the elasticity of the movable contact. A pair of movable pieces are provided facing each other at positions sandwiching the movable contact in the direction of deformation, and the movable pieces are displaced in one direction and the opposite direction when the ribbon is fed out to the end under no load and vice versa when overloaded. A ribbon end detection mechanism for a printer, wherein the ribbon end detection mechanism for a printer is configured to selectively conduct contact with the pair of fixed contacts to detect the no load or overload. 2. The above-mentioned leaf switch has a structure having a plurality of fixed contacts and a plurality of movable contacts that contact and separate from each of the fixed contacts.Claim 1 of Claims for Utility Model Registration
Ribbon end detection mechanism of the printer described in section.