JPS6345311Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a recording paper end detection device for a tractor in a printer.

Most printers used as computer terminals generally use recording paper with feed holes formed at equal pitches on both sides, and also have feed pins that engage with the feed holes to feed this recording paper in a stable state. A tractor equipped with a paper feeder is used. In order to prevent blank printing, conventionally, a sensor such as a photocoupler is attached to the feed pin of a tractor to detect the end of the recording paper, but attaching a sensor to the feed pin is a difficult task. Therefore, it is not suitable for users to easily wear it as an option. In particular, a circuit that automatically stops the printing operation and paper feeding operation based on the electric signal from the sensor is more troublesome.

This device can detect the end of the recording paper and automatically stop the printing operation and paper feeding operation, and furthermore, it does not deform the recording paper so much that it does not interfere with its feeding. It is an object of the present invention to provide a recording paper end detection device for a tractor in a printer that can be easily installed later as an option.

In this invention, a tractor is provided with a paper feeding section having feed pins that engage with feed holes formed at equal pitches on both sides of the recording paper, and a joint part that comes into contact with the recording paper is formed protrudingly in the center. A detecting body biased in one direction so as to be resiliently joined to the recording paper is rotatably provided, and the detecting body operates when the recording paper of this detecting body runs out, facing a part of the detecting body. A switch is selectively installed in the power supply circuit to turn off the power. Therefore, since the joint that comes into contact with the recording paper is located at the center and is formed to protrude, the center of the recording paper can be recessed and deformed into a boat bottom shape. Even if there are creases, there is no risk of the paper being folded, and it can be fed out smoothly. In addition, the simple structure of installing a detector in the path of the paper and connecting a switch to the power supply circuit allows the paper to be easily fed out. The structure is such that the signal can be reliably obtained.

An embodiment of this invention will be explained based on the drawings.
1 is the printer body, and inside this is the print head 2.
A platen 3 and a motor (not shown) for driving the platen 3 are housed therein, and an opening 4 facing the platen 3 is formed in the upper surface of the printer main body 1 .

A tractor 5 is then provided. This tractor 5 includes opposing frames 6 and frame covers 7 fixed to the outside of these frames 6 and attached to both sides of the upper surface of the printer main body 1.
, a rotating shaft 8 and supporting shafts 9 and 10 respectively installed on the frame 6, and these rotating shafts 8 and supporting shafts 9.
It consists of a paper feeding section 11 which is held slidably and fixed at any position, and a power transmitting section 12 built into one of the frame covers 7. The paper feeding section 11 includes a pulley 13 fitted onto the rotation shaft 8 while being prevented from rotating, a pulley 14 fitted onto the support shaft 9, and a belt 15 wound around these pulleys 13 and 14. is housed in a U-shaped case 16, and windows 18 are formed on the upper and lower surfaces of these cases 16 to release the feed pin 17 formed on the outer surface of the belt 15. The power transmission section 12 includes a pulley 19 fixed to the right end of the rotating shaft 8, a pulley 21 connected to the pulley 19 by a belt 20, and a pulley 21 that is integrally connected to the pulley 21 and connected to the frame 6 on the right side. It consists of a gear 22 held by the frame 6 and a gear 23 held by the frame 6 and meshed with the gear 22. A gear 24 that meshes with the gear 23 is fixedly fitted on the right side of the platen 3. Further, a support shaft 2 of the platen 3 is provided at the lower front end of the frame 6.
A hook 26 is formed which is engaged with 5.

Next, two paper guides 27 and 28 made of wires are installed on the frame 6. Thus, a detection body 29 is provided. This detection body 29 is formed by bending a wire, and consists of a presser bar 30 extending in the left-right direction and arms 31 bent on both sides of the presser bar 30. A hook 32 rotatably held on the support shaft 10 is formed, and the arm 3
A protrusion 33 is formed on one side of the push rod 30 by welding an L-shaped wire, and by bending the center of the push rod 30 downward, it is elastically joined to the recording paper 34 with a small contact area. Joint part 3
5 is formed to protrude toward the recording paper 34. Furthermore, recesses 36 are formed in the arm 31, and support portions 37 formed by pins located above these recesses 36 are provided on the inner surface of the frame 6. The protrusion 33 is attached to the printer main body 1
It protrudes inward from a hole 38 formed in the upper surface of the switch 39 and faces the switch 39 at a predetermined distance.
This switch 39 is a normally cross type switch and is connected to a power supply circuit, forming a series circuit with a power supply switch (not shown).

The recording paper 34 is inserted into the upper inner surface and the lower inner surface of the case 16 of the paper feeding section 11, and a number of feeding holes (not shown) into which the feed pins 17 engage are formed at equal pitches on both sides. It is something.

In such a configuration, normally when printing is performed while rotating the platen 3 intermittently clockwise, the belts 15 and 20 also rotate clockwise to feed the recording paper 34 line by line. At this time, the detection body 29 is urged downward by its own weight (or a spring) and elastically joins to the recording paper 34 with the joining portion 35 . When printing is performed by rotating the platen 3 and belts 15 and 20 counterclockwise, the tension on the recording paper 34 is weakened between the paper feed section 11 and the paper guide 28. Therefore, since there is a risk that the recording paper 34 with a crease that is folded in a zigzag pattern may be folded near the joint 35 of the detection body 29, only the central part of the recording paper 34 is pushed by the narrow joint 35. An external force is applied to curve the recording paper 34 somewhat into the shape of the bottom of a boat. Therefore, the recording paper 34
The paper becomes stiffer in the folding direction, and is smoothly fed between the paper feeder 11 and the paper guide 28 while being stretched. Such an effect can also be obtained by providing a roller 40 at the center of the presser bar 30 which is stretched linearly as shown in FIG.

Then, when the recording paper 34 runs out, the detection body 29 supported by the tension of the recording paper 34 rotates downward about the hook 32 and uses the protrusion 33 to turn off the switch 39. Therefore, the printing operation and paper feeding operation are automatically stopped.

Note that the detection body 29 has recesses 3 formed on both sides thereof.
It is also possible to position it out of the path of the recording paper 34 by engaging the support part 6 on the support part 37. In addition, the paper guides 27 and 28 and the detection object 29
has a width that corresponds to the maximum width of the recording paper 34 to be used, and printing can be performed on recording paper 34 of various sizes by adjusting the interval between the paper feeding sections 11.

In this way, the function of detecting the end of the recording paper 34 can be achieved by simply attaching the detector 29 to the tractor 5 and connecting the switch 39 to the power supply circuit, and can be easily installed later as an option.

As described above, this invention includes a tractor equipped with a paper feeding section having feed pins that engage feed holes formed at equal pitches on both sides of the recording paper, and a joint section in the center that abuts the recording paper. A detecting body formed in a protruding manner and biased in one direction so as to be resiliently joined to the recording paper is rotatably provided, and the recording paper of this detecting body runs out when facing a part of the detecting body. Since we have selectively installed a switch in the power supply circuit that turns OFF when the paper is turned off, the joint that comes into contact with the recording paper is located in the center and is formed protrudingly. As a result, even if the recording paper has creases, there is no risk of it being folded, and the recording paper can be fed out smoothly. It has the advantage of being able to reliably obtain a recording paper end signal with a simple structure that requires only a detection body and a switch connected to the power supply circuit.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is an exploded perspective view, FIG. 2 is a partially sectional vertical side view, FIG. 3 is a perspective view of the detection body, and FIG. 4 is a perspective view showing a modification of the detection body. 5...Tractor, 11...Paper feeding unit, 17...
Feed pin, 29...Detection object, 39...Switch.

Claims (1)

[Scope of utility model registration request] A tractor is provided with a paper feeding section having feed pins that engage with feed holes formed at equal pitches on both sides of the recording paper, and a joint portion that abuts the recording paper is formed protrudingly in the center to allow the recording paper to A detecting body biased in one direction so as to connect elastically is rotatably provided, and is turned off by operation when the detecting body runs out of recording paper, facing a part of the detecting body. A recording paper end detection device for a tractor in a printer, characterized in that a switch is selectively provided in a power supply circuit.