JPH0412234B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to paper feeding by the rotational movement of a sprocket with a paper feeding pin (hereinafter referred to as pin feed),
The present invention relates to a paper feeding mechanism of a printing device including two paper feeding mechanisms, one of which is a paper feeding mechanism in which the paper feeding roll is rotated while the paper feeding roll is in pressure contact with a presser roller (hereinafter referred to as a friction feed).

[Prior Art] In a printing device equipped with two paper feeding mechanisms, a pin feed and a friction hood, when the pin feed is used, the amount of paper fed by the paper feeding pin and the amount of paper fed by the paper feeding roll do not match. There is a drawback that the paper feeding accuracy is poor due to the pin coming off from the paper feed hole (the hole is broken) or the paper becoming loose.To overcome these drawbacks, in the case of pin feed, friction feed It is common to cancel the function.

This conventional example will be explained using FIGS. 5 and 6. As shown in the figure, the sprocket shaft 10 fixed through the paper feed pin sprocket 7 for pin feed and the paper feed drive shaft 3 fixed through the paper feed roll 1 for friction feed are parallel to each other. The rotational force is transmitted from a paper feed motor (not shown) to the sprocket shaft 10 and the paper feed drive shaft 3 via a gear (not shown). In the case of pin feed, the paper 8 is wound around the paper feed roll 1 and the sprocket 7 about half a turn, and the feed hole 8a of the paper 8 enters the pin 7a provided on the outer periphery of the sprocket 7, and the sprocket 7 rotates in this state. The paper 8 is pulled and conveyed by the paper 8. and paper 8
is printed by the printing head 9 on the portion wrapped around the paper feed roll 1.

In addition, in the case of a friction feed, the paper 8 is not wound around the sprocket 7 and the paper feed roll 1
When the paper 8 is wrapped around the sprocket 7 and the presser roll 2 is in a position opposite to the sprocket 7 when viewed from the print head 9 of the paper feed roll 1, the paper feed roll The paper 8 is conveyed by rotating the paper 1.

The friction feed is released by separating the presser roller 2 from the paper feed roll 1.

[Problem to be solved by the invention] However, normally the pin 7a of the sprocket 7
In order to accommodate the error in the paper feed hole diameter or the feed hole position, the pin 7a is smaller than the paper feed hole diameter.
Because the diameter of the paper feed pin is set small, even if the friction feed function is canceled during pin feed as described above, the friction between paper feed roll 1 and paper 8 is small, so the paper feed pin diameter is set to It is difficult to remove the looseness of the paper caused by the diameter of the hole being smaller than the diameter of the hole, and there is still a drawback that paper feeding accuracy cannot be achieved.

[Means for Solving the Problems] In order to solve the above-mentioned drawbacks, the present invention provides a pin feed that is located downstream of the printing position and feeds paper by the rotational movement of a sprocket with a paper feeding pin, and a In a printing device equipped with two paper feeding functions of a friction feed, which feeds paper by the rotational movement of the paper feeding roll while the paper feeding roll and the presser roller are positioned in pressure contact with each other, the paper feeding roll is rotationally driven. A paper feed drive shaft is disposed coaxially with the paper feed roll, a clutch plate is attached to the paper feed drive shaft so as to be integrally rotatable, and the pressing force of the clutch plate toward the paper feed roll is set to the pin feed. The present invention is characterized in that a clutch mechanism is provided with a pressing force adjusting means for changing the pressing force from weak to strong in the case of the friction feed.

[Effect] The above means works as follows.

By changing the rotational force of the paper feed drive shaft transmitted to the paper feed roll and the pressing force of the clutch plate of the clutch mechanism against the end face of the paper feed roll, even in the case of pin feed, the paper feed roll can maintain appropriate friction against the paper. By securing power and providing appropriate resistance,
Allows for highly accurate paper feeding.

[Example] Hereinafter, an example of the present invention will be described using FIGS. 1 to 4.

In the embodiment shown in FIGS. 1 and 2, the presser roller 2 is always in a fixed position relative to the paper feed roll 1. In the embodiment shown in FIGS. Further, this paper feed roll 1 is not fixed to the paper feed drive shaft 3, and can rotate idly. And this paper feed drive shaft 3 and paper feed roll 1
The paper feeding force is transmitted between the paper feeding roll 1 and the clutch plate 4 by the frictional force generated by the pressing force between the end surface of the paper feeding roll 1 and the clutch plate 4. This clutch plate 4 is located on one end surface side of the paper feed roll 1 in the axial direction of the paper feed drive shaft 3, and although it moves in the axial direction, it is rotated by the action of the key 3a on the paper feed drive shaft. The rotation is restricted so that it rotates integrally with 3. This clutch plate 4 is interlocked with a change spring 6 that moves in the axial direction via a clutch spring 5 attached to the outer periphery of the paper feed drive shaft 3, and by moving the change spring 6 in the axial direction, the end face of the paper feed roll 1 is The frictional force between the paper feed roll 1 and the clutch plate 4 can be changed by changing the pressing force between the paper feed roll 1 and the clutch plate 4 pressed against the end face thereof. In this way, the transmission force between the paper feed drive shaft 3 and the paper feed roll 1 can also be changed. That is, the end surfaces of the clutch plate 4 and the paper feed roll 1 are as follows.
They are a friction surface that can rotate integrally with the paper feed drive shaft 3 and a friction surface that can rotate integrally with the paper feed roll 1, respectively, and the clutch spring 5 and the change lever 6 are configured to reduce the friction force between the two friction surfaces. This constitutes a pressing force adjusting means that changes the pressing force according to the pressing force.

Next, each paper feeding mechanism will be explained.
In the case of a friction feed in the above-mentioned configuration, it is necessary to strengthen the transmission force from the paper feed drive shaft 3 to prevent the paper feed roll 1 from idling, so by moving the change lever 6 toward the paper feed roll 1 side. Increase the frictional force on both frictional surfaces.
By doing so, the rotational force of the paper feed drive shaft 3 is reliably transmitted to the paper feed roll 1, and the paper 8 held between the presser roll 2 and the paper feed roll 1 is conveyed with high precision. In the case of a pin feed, the transmission force of the rotational force of the paper feed drive shaft 3 is weakened and transmitted to the paper feed roll 1, and the rotation of the sprocket 7 feeds the paper 8.
The paper feed roll 1 is rotated through the .
That is, by moving the change lever 6 toward the paper feed drive shaft 3 side, the friction force on both of the friction surfaces is weakened. By doing this, an appropriate back tension is applied to the paper 8, thereby eliminating play between the paper feed hole and the pin 7a or slack in the paper due to variations in the dimensional accuracy or positional accuracy of the paper feed hole. becomes possible.

Next, another embodiment will be described using FIGS. 3 and 4. This embodiment is different from the first embodiment described above in that the paper feed roll shaft 11 passes through the paper feed roll 1, and the paper feed shaft side clutch plate 4b fixed to the paper feed roll shaft 11 is connected to the paper feed roll 1. When pressed against the paper feed drive shaft side clutch plate 4a fixed to the paper feed drive shaft 3 having the same center line, a frictional force is generated and the rotational force of the paper feed drive shaft 3 is transmitted to the paper feed roll 1. This is what I did.
Then, the paper feed drive shaft 3 is made movable in the axial direction,
By moving the change lever 6 in the axial direction, the paper feed drive shaft 3 is moved in the axial direction, thereby changing the pressing force of the clutch plates 4a and 4b.

Further, in each of the above embodiments, the paper feed roll 1 also serves as the platen, but the present invention can also be applied to a case where the paper feed roll and the platen are configured separately.

[Effect] As explained above, in the present invention, the paper feed drive shaft that rotationally drives the paper feed roll is disposed coaxially with the paper feed roll, and the clutch plate is attached to the paper feed drive shaft so as to be integrally rotatable. Furthermore, by providing a clutch mechanism equipped with a pressing force adjusting means for changing the pressing force of the clutch plate toward the paper feed roll side so that it is weaker in the case of the pin feed and stronger in the case of the friction feed. Even in the case of pin feed, a moderate amount of resistance (back tension) is obtained against the paper on the paper feed roll side. It is possible to eliminate looseness or slack in the paper, allowing for highly accurate paper feeding.
This provides a remarkable effect.

[Brief explanation of drawings]

1 to 4 each show an embodiment of the present invention, FIG. 1 is a schematic front view of the main part including a partial cross section showing one embodiment, and FIG. 2 is the same as FIG. 1. FIG. 3 is a side view of the embodiment shown, FIG. 3 is a schematic front view of the main part including a partial cross section showing another embodiment, and FIG.
5 is a side view of the embodiment shown in the figure, FIG. 5 is a schematic front view of the main part including a partial cross section showing the conventional example, and FIG. 6 is a side view of the embodiment shown in FIG. 5. . 1... Paper feed roll, 2... Presser roll, 3... Paper feed drive shaft, 4... Clutch plate, 5... Clutch spring,
6...Change lever, 7...Sprocket with pin, 8
…paper.

Claims (1)

[Claims] 1. A pin feed that is located downstream of the printing position and feeds the paper by the rotational movement of a sprocket with a paper feeding pin, and a paper feeding roll and a presser roller that are located upstream of the printing position are in pressure contact and the paper feeding roll is rotated. In a printing device equipped with two paper feeding functions of a friction feed that feeds paper by motion, a paper feeding drive shaft that rotationally drives the paper feeding roll is disposed coaxially with the paper feeding roll, and
A clutch plate is rotatably attached to the paper feed drive shaft, and the pressing force of the clutch plate towards the paper feed roll is changed so that it is weaker in the case of the pin feed and stronger in the case of the friction feed. 1. A paper feeding device for a printing device, characterized in that it is provided with a clutch mechanism equipped with a pressing force adjusting means.