JP2903619B2 - Dot line printer paper feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder for a dot line printer, and more particularly, to a support method for slidably supporting a paper feed mechanism on a main body mechanism. It is about.

[Background of the Invention]

The functions to be provided in the paper feeder of the dot line printer to which the present invention is applied and problems in the conventional paper feeder will be described with reference to FIG.

The main functions that the paper feeder should have are the following four items.

First, the printing paper (hereinafter referred to as paper) 1 is transported in dot row units. For this purpose, a means for driving a pair of paper feed tractors 2 on which the paper 1 is applied by a stepping motor 4 via a timing belt 3 is usually used.

Second, it supports the printing force from the hammer bank 5, which stores and holds a plurality of printing hammers (not shown) for dot printing. As a component for supporting the printing force, a platen 6 in which the outer periphery of a metal shaft is coated with hard rubber is used. The platen 6 also serves as a guide for running the paper 1. The ink ribbon 7 travels between the hammer bank 5 and the paper 1 in a direction perpendicular to the plane of the drawing.

Third, the distance between the tip of the print pin of the print hammer in the hammer bank 5 and the platen 6 (hereinafter referred to as a hammer gap).
Is a hammer gap setting function for setting to a predetermined value. In this type of dot line printer, various types of paper 1 having different thicknesses are used. In order to optimize the printing characteristics of the printing hammer, the hammer gap must be adjusted according to the thickness of each sheet 1. In the paper feeder, each component is mounted on a paper feed frame 10, and a rotating bearing 11 is provided below the paper feed frame 10, and the entire paper feeder is rotated around this to change the hammer gap. . For this purpose, the ET cam 8 attached to the FT shaft 9 is rotated by a lever (not shown). The FT cam 8 is fitted in a groove 13 'of a hook lever 13 rotatably mounted via a hook lever shaft 12 to a mechanical frame for supporting a main body mechanism (not shown). This groove 13 '
The spring 14 is provided so that the backlash of the FT cam 8 does not occur.

Fourth, there is a platen opening / closing function for detaching the paper 1 and the ink ribbon 7. The opening and closing of the platen means that the platen 6 is made large from the hammer bank 5 or returned to the original hammer gap. For this purpose, the hook lever 13 is turned clockwise in the drawing. As a result, FT
The cam 8 moves to the position indicated by the symbol A on the hook lever 13, and the entire paper feeder rotates about the rotation support shaft 11. When the paper feeder is returned to the original position, the paper feeder can be pulled back to the left in the drawing. The platen opening / closing function is a function necessary for cleaning the hammer bank 5 and its lower part, and also for maintenance work.

The paper feeder having the above configuration has the following problems and needs to be improved.

The biggest problem relates to the support rigidity of the paper feeder. The paper feeder must have sufficient support rigidity so that the hammer gap does not change as much as possible with respect to the printing force of the printing hammer of the hammer bank 5. If the support stiffness is insufficient, the hammer gap changes due to the effect of the printing force, causing a reduction in the printing density (worst case is the removal of dots) and a disorder in the dot position, which greatly deteriorates the printed product label. The change of the hammer gap allowed from the characteristics of the printing hammer is several μm. The printing power of a large number of printing hammers reaches 100N on average. It can be a multiple of that momentarily. This printing force acts on the platen 6, and in the following order, the paper feed frame 10, the FT shaft 9, the FT cam 8, the hook lever 13, and the hook lever shaft.
It is transmitted to 12, and finally transmitted to a mechanical frame (not shown). On the other hand, the entire paper feeder is rotated by the support shaft 11 for rotation.
It is rotatably supported by a mechanical frame. In the above configuration, since the component for supporting the printing force is located below the direction of the printing force indicated by the arrow B and located below, the printing is particularly performed on the FT cam 8 and the hook lever 13 among the components. The force acts in an expanded manner. It is sufficient to have sufficient rigidity for this large load, but in reality it cannot be realized due to restrictions on mounting space and the like.

Furthermore, the rotatable shaft and hole fitting portion of each portion (the hole of the FT shaft 9 and the paper feed frame 10, the hole of the hook lever shaft 12 and the hook lever 13, the rotation support shaft 11)
Since there is a gap of about several μm between the paper feed frame 10 and the paper feed frame 10, a functional vibration of the entire paper feed device occurs due to the influence of the printing force. This is because the printing force is not a constant load but becomes an intermittent load by alternately repeating printing and paper feeding. The amplitude at the position of the platen 6 due to this vibration may reach 100 μm or more in some cases. In order to prevent this, the processing accuracy is increased so that the above-mentioned gap is made as small as possible. Further, in the case where the speed of the printing apparatus is further increased, the problem of the change of the hammer gap is fatal because the printing force increases in accordance with the speeding up.

[Object of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to solve the problem of insufficient support rigidity of the paper feeder, and to improve the maintainability of the paper feeder.

[Summary of the Invention]

The present invention focuses on the fact that supporting the printing force in the direction in which the printing force acts is directly useful for improving the support rigidity, and contrived to provide components for supporting the printing force on the printing force action line. It was done. Furthermore, by applying a pressurizing force in one direction so as to eliminate the gap between the fitting portion of the shaft and the hole, the vibration generated by the intermittently acting printing pressure is suppressed so that it is devised. is there.

(Example of the invention)

A description will be given with reference to FIGS. 1 to 3 showing an embodiment of the present invention. Except for the parts described in detail below, the description is omitted because it is the same as the prior art.

In FIG. 1, a platen 6 is rotatably mounted on a paper feed frame 10 via a platen holder 15 with a ball bearing, and is driven by a motor (not shown). The printing force acting direction from the hammer bank 5 is the direction indicated by the arrow B. Means for setting the hammer gap in this direction, that is, hammer gap setting means is provided. This hammer gap setting means uses the FT cam 8
Are rotatably attached to the paper feed frame 10 via the FT shaft 9 and the FT adjustment plate 16. The FT adjust plate 16 has a function as an eccentric cam and adjusts the hammer gap to a predetermined value at the time of assembly.

On the other hand, the opening / closing means for the platen mounted on the paper feeder has the following configuration.

Swing arm with bearing 17 attached to FT cam 8
Reference numeral 18 is attached to a swing arm shaft 19, which is a rotation shaft, by a bolt 20. The swing arm shaft 19 is rotatably mounted on a guide frame 21 which is a part of a mechanical frame (not shown) for supporting the entire main body mechanism. The swing arm 18 can rotate the swing arm shaft 19 clockwise by about 90 degrees. Above the bearing 17 mounted on the tip of the swing arm 18, a pair of plates 22
Mounted on Further, a guide pin 23 is attached below the paper feed frame 10. A backup spring 24 is attached to the lower right back surface of the guide frame 21 so as to apply a spring force in the direction shown in FIG.

In the above configuration, the printing force acts in the direction of arrow B as described above, but is transmitted by the platen 6, the platen holder 15, the paper feed frame 10, and the FT adjustment plate 1.
6, FT shaft 9, FT cam 8, bearing 17, swing arm 1
8, the swing arm shaft 19 and finally the guide frame 21. As can be seen, all the components on which the printing force acts are provided along the line of action of the printing force, and the stiffness of this support system is the highest since it does not receive any extra moment.

The setting direction of the swing arm 18 is set at a slight angle with respect to the printing force action direction B.
18 ′ is provided so that the stopper 18 ′ is positioned against the guide frame 21. This angle is α, which prevents the swing arm 18 from turning counterclockwise in the figure due to the action of the printing force.

Paper feed frame by backup spring 24
10 is pushed rightward in the figure as described above. Therefore,
The FT cam can be prevented from moving away from the bearing 17.

Not only this, but also the shaft and hole fitting part of each part (for example, the hole of FT shaft 9 and FT adjustment plate 16,
In the gap between the swing arm shaft 19 of the bearing 17 and the hole of the guide frame 21), it acts so as to be always suppressed in one direction, so that the entire paper feeder can be prevented from vibrating due to intermittent printing force. It is better to set the load as the pressurization higher than the printing force. The reason why the bearing 17 is provided at the tip of the swing arm 18 is to prevent the swing arm 18 from swinging when the FT cam 8 is turned to change the hammer gap according to the thickness of each sheet 1.

Each component having the above-described configuration is provided as a pair from the opposite side of the mechanical frame. As is apparent from FIG. 2 showing the state, the paper feed frame 10 and the guide frame
The spacing of 21 is narrow. This is to prevent an unnecessary moment (which causes an increase in deformation) between the components supporting the printing force due to the action of the printing force.

In FIG. 2, a print hammer 25 is provided in the hammer bank 5. The hammer bank 5 is connected to a shuttle mechanism 26 constituted by a motor, a cam, and the like (not shown), and reciprocates in the horizontal direction in the figure, that is, in the spar direction.

FIG. 3 shows a state in which the platen is opened and closed by means for opening and closing the platen, that is, the state of the platen opening and closing means when the platen is opened and closed.

When the swing arm 18 is rotated clockwise through a lever or the like (not shown), the bearing enters between the pair of plates 22 attached to the paper feed frame 10. When the swing arm 18 is further turned, the right plate 22 hits the bearing 17, so that the paper feed frame 10 moves parallel to the right in the drawing as the swing arm 18 rotates. The guide for this movement is the guide pin 23 attached to the paper feed frame 10 and the groove 21 'of the guide frame 21 on the left side, and the groove 10' and the swing arm shaft 19 on the right side of the paper feed frame 10. is there. In FIG. 3, a groove 23 'is provided in the guide pin 23 so that the paper feed frame 10 does not move relative to the guide frame 21 in the direction perpendicular to the plane of the drawing.
The guide frame 21 and the plate are fitted together.

When the swing arm 18 is further turned clockwise from the state shown in FIG. 3, the entire paper feeder moves further rightward. When the respective grooves 10 ′ and 21 ′ are opened, the guide portion is released by lifting the paper feeder upward, so that the paper feeder can be easily taken out. This facilitates maintenance of the paper feeding device.

〔The invention's effect〕

According to the present invention, components for supporting the printing force in the printing action direction are arranged, and a pressurizing mechanism is provided to prevent an unnecessary moment from acting and to kill the moment of the portion where the printing force is transmitted. Therefore, the support rigidity of the paper feeder can be greatly improved. Further, since the guide pin is provided with a groove to be fitted to the guide frame, it is possible to eliminate the backlash in the left and right direction of the paper feeder and to prevent the occurrence of vibration. Since the change in the hammer gap can be suppressed by the improvement of the rigidity and the prevention of vibration as described above, the deterioration of the printing quality can be prevented. Further, the slide guide of the paper feeder is a guide for guide composed of a pair of front and rear shafts and grooves, and the relationship between the shaft and the groove is reversed before and after, so that the paper feeder can be easily removed. And maintainability can be improved.

[Brief description of the drawings]

1 is a side view showing an embodiment of the apparatus of the present invention, FIG. 2 is a cross-sectional view of FIG. 1 taken along a line of action of printing force, and FIG. 3 is a view showing a state when a platen is opened in FIG. FIG. 4 is a side view showing a conventional paper feed mechanism. In the figure, 5 is a hammerbank, 6 is a platen, 8 is FT
Cam, 9 is FT shaft, 10 is paper feed frame, 10 ', 2
1 'is a groove, 17 is a bearing, 18 is a swing arm, 18' is a stopper, 19 is a swing arm shaft, 21 is a guide frame, 22 is a plate, 23 is a guide pin, and 24 is a backup spring.

Claims (4)

(57) [Claims] A hammer bank for accommodating and holding a plurality of print hammers; a shuttle mechanism for reciprocating the hammer bank in a digit direction; at least one pair of paper feed tractors for feeding print paper; A paper feed mechanism having a platen for supporting the printing force of the tractor, the tractor, and a paper feed frame for supporting the platen; and a guide frame for supporting the paper feed frame slidably in the direction of the printing force of the printing hammer. A dot hammer gap setting device for securing optimal printing between the printing hammer and the platen, and a distance between the printing hammer and the platen on the printing force line of action of the printing hammer. Platen opening / closing means for wide opening, and the hammer gap setting means and the platen opening / closing hand are provided. A paper feeder for a dot line printer, wherein the steps are installed so as to abut each other. 2. A pressurizing means is provided between the paper feed frame and the guide frame so as to maintain contact between the hammer gap setting means and the platen opening / closing means. Dot line printer paper feeder. 3. The hammer gap setting means has a pair of cams, and the platen opening / closing means has a pair of swing arms. When the platen is closed, the cam and the swing arm are brought into contact with each other to make the printing force of the printing hammer. 2. A paper feeder for a dot line printer according to claim 1, wherein a bearing is provided at a portion where the swing arm contacts the cam. 4. When the platen is closed, a straight line connecting the rotation center of the swing arm and the contact portion when the swing arm contacts the cam and a printing force action line rotate the swing arm under the influence of the printing force. 4. A paper feeder for a dot line printer according to claim 3, wherein the paper feed device is provided with an angle that does not move the paper.