JPH07195788A - Paper feed device of printer - Google Patents

Abstract

PURPOSE:To accurately realize the fine feed of paper without generating the pitch shift of a ratchet wheel even when the engaging pawl engaged with the ratehet wheel is disengaged. CONSTITUTION:A paper feed roller 6 equipped with a ratchet wheel 4 is attached to the rotary shaft 3 supported on an apparatus main body 2 and always driven in a paper feed-out direction through an one-way clutch transmitting power to the paper feed roller 6 from the rotary shaft 3 only when the paper feed roller is rotated in a forward paper feed-out direction and a roll feed member 8 integrally having the engaging pawl 9 engaged with the tooth part 5 of the ratchet wheel 4 and the follower pawl 10 opposed to the engaging pawl 9 is provided and supported on the side of the apparatus main body 2 in a freely shakable manner. Further, an energizing means 11 allowing the engaging pawl 9 and the follower pawl 10 to face to the tooth part 5 of the ratched wheel 4 and energizing the engaging pawl 9 of the roll feed member 9 so as to engage the same with the tooth part of the ratchet wheel 4 and a roll feed member driving means 12 detaching the engaging pawl 9 against the energizing force of the energizing means 11 to contrarily engage the follower pawl 10 with the tooth part 5 to be deenergized are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device for a printer, for example, for minutely feeding printing paper in a printer.

[0002]

2. Description of the Related Art One printing sheet mounted on a platen
As a means for sending dot lines one by one, for example, a printing hammer bank that reciprocates with a constant amplitude, and a platen that winds a printing paper that is printed by the printing operation of the printing hammer bank and performs a printing paper transport operation, A pawl driven by at least one of a printing hammer bank and a balancer that reciprocates in conjunction with the printing hammer bank, a pawl wheel engaging with the pawl, and the rotation of the pawl wheel are transmitted to the platen by decelerating a predetermined amount. A printing paper transporting device including a transmitting means is known from Japanese Patent Laid-Open No. 59-78874.

This device is provided with a ratchet wheel mounted on a shaft linked to a platen for winding the print paper and carrying out the print paper transport operation, and a lever having an intermediate portion as a shaft. The lever is attached to one end of the lever. One end of a link driven by reciprocation of a hammer bank is connected, a locking claw is provided between a lever support shaft and a link connecting part, and the locking claw is provided at the other end of the lever. It is biased toward the ratchet wheel by the hammer bank, and when one end side of the lever moves due to the operation of the hammer bank, the locking claw part disengages from the ratchet wheel and the spring is stretched. The locking claw portion rotates toward the ratchet wheel by the restoring force of the spring and pushes the claw portion of the ratchet wheel to rotate the ratchet wheel by one tooth.

However, in this device, when the locking claw portion is disengaged from the ratchet wheel by the operation of the hammer bank, the ratchet wheel is released from the locking state and is in a free state. Therefore, it is considered that a pitch shift occurs at this time. In such a case, when the locking claw part rotates toward the ratchet wheel and presses the claw part of the ratchet wheel to rotate the ratchet wheel, tooth jumping occurs and the minute feeding of the printing paper is disturbed. Will occur.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to accurately and minutely feed a sheet without causing a pitch deviation in the ratchet wheel even when a locking claw engaging with the ratchet wheel is disengaged. It is to provide a paper feed device for a printer that can be realized.

[0006]

In order to solve the above problems, a paper feeding device for a printer of the present invention is provided with a ratchet wheel on a rotary shaft that is supported by the main body of the device and is constantly driven in the paper feeding direction. The paper feed roller is mounted via a one-way clutch in which power is transmitted from the rotary shaft to the paper feed roller only when the paper feed roller is rotated in the forward direction to feed the paper between the paper feed roller and the rotary shaft, A frame feeding member integrally having a locking pawl that engages with the tooth portion of the ratchet wheel and a driven pawl facing the locking pawl is provided, and the frame feeding member is pivotally supported on the apparatus body side. Along with the locking claw and the driven claw, the biasing means and the biasing means for biasing the locking claw of the frame feed member to engage with the tooth of the ratchet wheel. After releasing the locking claw against the bias of the biasing means and engaging the driven claw with the tooth part in reverse Characterized in that a said piece feeding member driving means is energized.

[0007]

The one-way clutch transmits power from the rotary shaft to the paper feed roller only when the rotary shaft and the paper feed roller that are constantly driven in the paper feed direction are rotated in the forward direction for feeding the paper.

When the frame feeding member driving means does not operate,
The frame feed member is at the initial position in the swing motion of the frame feed member. That is, the engagement claw of the frame feed member engages with the tooth portion of the ratchet provided on the paper feed roller by the urging force of the urging means, and the driven claw facing the locking claw is the tooth portion of the ratchet. Are separated from each other. At this time, since the pawl wheel provided on the paper feed roller is prevented from rotating in the forward direction for feeding the paper by the engagement of the locking pawl provided on the frame feed member, the power transmission of the one-way clutch is cut off. Then, only the rotating shaft is rotationally driven in the paper feeding direction.

The frame feed member driving means is operated when the print paper is finely fed. The frame feed member driving means is deenergized after the locking pawl provided on the frame feed member is released against the bias of the biasing means and the follower pawl is engaged with the tooth portion.

When the frame feed member driving means is operated, the frame feed member swings, the locking claws provided on the frame feed member are disengaged from the teeth of the ratchet wheel provided on the paper feed roller, and the locking claws are provided. The driven pawls facing each other engage with the teeth of the ratchet wheel. When the engaging claw is disengaged from the ratchet wheel, power is transmitted to the one-way clutch, so that the rotary shaft, the ratchet wheel, and the paper feed roller are about to rotate in the paper feeding direction. However, since the driven pawl is engaged with the tooth portion of the ratchet wheel, the ratchet wheel is prevented from being rotated more than necessary, and thus the pitch shift of the tooth portion of the ratchet wheel is prevented. The driven pawl that engages with the tooth portion of the ratchet wheel is pressed toward its initial position by the rotational force of the ratchet wheel.

When the frame feed member drive means is deenergized, the frame feed member is swayed to the initial position in the swing motion of the frame feed member by the urging force of the urging means and the pressing force applied to the driven pawl by the rotation of the ratchet wheel. The driven claw is disengaged from the tooth portion of the ratchet wheel and returned, and the locking claw engages with the tooth portion of the ratchet wheel, the ratchet wheel is locked, and the power transmission of the one-way clutch is cut off. Only the rotating shaft is rotationally driven in the paper feeding direction.

At this time, when the driven pawl exceeds one pitch of the tooth portion of the ratchet wheel, the ratchet wheel rotates by one pitch, and the paper feed roller rotates by one pitch together with the ratchet wheel. One pitch is fed in the feeding direction.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a paper feeding device of a printer according to an embodiment. The paper feeding device 1 includes a paper feeding device main body 2
Between the rotary shaft 3 and the paper feed roller 6 provided with a claw wheel 4 and a rotary shaft 3 that is supported in the direction of arrow a in FIG. A toothed portion 5 of the ratchet wheel 4 is provided with a one-way clutch (not shown) that transmits power from the rotation shaft 3 to the paper feed roller 6 only when the paper feed roller 6 is rotated in the forward direction for feeding the paper.
Locking claw 9 that engages with and driven claw 10 that opposes the locking claw 9
And a biasing means including a tension spring 11 for biasing the locking claw 9 of the frame feeding member 8 to engage with the tooth portion 5 of the ratchet wheel 4 and the biasing means. The engaging pawl 9 is removed against the bias and the driven pawl 10 is reversely attached to the tooth portion 5 of the ratchet wheel 4.
There is provided a frame feed member driving means including a solenoid 12 which is deenergized after being engaged with.

As shown in FIG. 1, the main body 2 of the paper feeding device is
It is composed of substantially triangular side plates 16a and 16b, and a bottom plate portion 15 between the lower portions of the both side plates 16a and 16b, and a recess 17 is formed substantially at the center of the bottom plate portion 15. A rotary shaft 3 and a roller shaft 18, which are transmitted from a printer body (not shown), are pivotally supported between the side plates 16a and 16b.

The rotary shaft 3 is provided so as to pass through the other side plate 16b, and a gear 28 is attached to the tip of the rotary shaft 3 penetrating outward from the other side plate 16b by an E ring 29. It meshes with a transmission means composed of a gear train that is linked to a drive motor of the printer body (not shown), and is constantly rotated in the direction indicated by arrow a in FIG.

On the rotary shaft 3, a paper feed roller 6 and a ratchet wheel 4 are provided.
Are integrally mounted via a one-way clutch. Figure 2
As shown in Fig. 1, the one-way clutch is composed of a spring clutch 7. The spring clutch 7 has connecting ends 7a, 7b protruding outward in the radial direction at both ends, and in a free state before assembly, the rotating shaft 3 is smaller than the diameter of 3, and is rotated together with the rotating shaft 3 by being fitted onto the rotating shaft 3, and the connecting end 7a,
When one of 7b is fixed and the rotating direction of the rotating shaft 31 is opposite to the winding direction of the spring clutch, the spring clutch is loosened and only the rotating shaft 3 rotates. In FIG. 2, the clockwise winding is performed from one connecting end 7a to the other connecting end 7b.

The ratchet wheel 4 is provided with teeth 5 along its outer circumference, and has a circular shaft insertion hole 4a in a radial cross section and a spring clutch engagement groove 4b communicating with the shaft insertion hole 4a in the radial direction.
Have. In the ratchet wheel 4, the rotary shaft 3 is inserted through the shaft insertion hole 4a, and the spring clutch engaging groove 4b provided in communication with the shaft insertion hole 4a in the radial direction is externally fitted to the rotary shaft 3. One of the connecting ends 7a of 7 is engaged and attached to the rotating shaft 3.

In the paper feed roller 6, rubber annular members 6d, 6d are integrally provided on the outer periphery of a cylindrical support member 6a. The support 6a has a shaft insertion hole 6b for inserting the rotary shaft 3 in the axial direction thereof, and has a ratchet wheel 4 at one end thereof.
It has a spring clutch engagement groove 6c that is equivalent to the spring clutch engagement groove 7b provided in the above. The paper feed roller 6 has a support 6
The rotation shaft 3 is inserted from one end side of the shaft insertion hole 6b provided in a, and the spring clutch 7 externally fitted to the rotation shaft 3 is inserted into the spring clutch engagement groove 6c provided at one end side of the shaft insertion hole 6b. The other connecting end 7b is engaged and attached to the rotary shaft 3.

That is, the ratchet wheel 4 and the paper feed roller 6 are integrated by the one-way clutch 7, and the rotary shaft 3, the paper feed roller 6 and the ratchet wheel 4 are connected via the one-way clutch 7.
The one-way clutch 7 is connected to transmit power from the rotary shaft 3 to the paper feed roller 6 only when the paper feed roller 6 is rotated in the forward direction for feeding the paper.

A friction roller 19 that comes into contact with the paper feed roller 6 is rotatably mounted on the roller shaft 18, and as shown in FIG. 1, the paper P is sandwiched between the paper feed roller 6 and the friction roller 19. The paper is fed in the paper feed direction indicated by the solid arrow b.

As shown in FIGS. 1 and 3, a locking claw 9 that engages with the tooth portion 5 of the ratchet wheel 4 and a driven claw 10 that faces the locking claw 9.
The frame feed member 8 integrally including and has the engaging claw 9 and the driven claw 10 facing the tooth portion 5 of the ratchet wheel 4, and is pivotally supported on the side of the paper feed device body 2 so as to be swingable. Further, a tension spring 11 for urging the locking claw 9 of the frame feeding member 8 to engage with the tooth portion 5 of the ratchet wheel 4 is provided.

As shown in FIG. 3, on the upper surface of the bottom plate portion 15 of the paper feeding device main body 2, a plate-shaped supporting body 20 is integrally erected upright toward the front concave portion 17, and on the side surface of the supporting body 20. Is provided with a support shaft 21 integrally. Further, a spring locking convex portion 22 is provided so as to project near the rear edge of the upper surface of the bottom plate portion 15.

As shown in FIG. 3, the frame feed member 8 has a shaft hole 23 in its central portion 8c, extends in opposite directions from the central portion 8c, and has its front end directed toward the opposite inner side. The curved portion 8 is provided with two curved portions 8a and 8b.
A locking claw 9 is formed on the inner side of the tip of a while the curved portion 8 is formed.
A driven claw 10 is formed inside the tip of b. Also,
A metal plate-shaped armature 24 is integrally provided below the central portion 8c of the frame feeding member 8, and a spring locking convex portion 25 is formed at one edge of the armature 24.

The frame feed member 8 has its locking claw 9 and driven claw 10 exposed from the lower side of the ratchet wheel 4 to the tooth portion 5 of the ratchet wheel 4.
A support shaft 21 provided on a support 20 on the side of the paper feed device main body 2 is fitted into a shaft hole 23 provided in the central portion 8c of the frame feed member 8 and is swingably supported.

Then, the spring locking convex portion 25 formed on the armature 24 integral with the frame feeding member 8 and the spring locking convex portion 2 protrudingly provided on the upper surface of the bottom plate portion 15 on the side of the main body 2 of the paper feeding device.
A tension spring 11 is stretched between the tension spring 1 and
Due to the biasing force of 1, the locking claw 9 of the frame feed member 8 is engaged with the tooth portion 5 of the ratchet wheel 4.

At this time, the locking claw 9 of the frame feeding member 8
The driven claw 10 facing each other is separated from the tooth portion 5 of the ratchet wheel 4, and the lower end of the armature 24 is in contact with the side wall 17a of the concave portion 17, so that the frame feeding member 8 is initially swung. The position is set.

The solenoid 12 which is deenergized after the locking pawl 9 is removed against the bias of the tension spring 11 and the driven pawl 10 is engaged with the tooth portion 5 of the ratchet wheel 4 in reverse, is It is provided in front of the upper armature 24. Solenoid 12
The yoke portion 26 is screwed and attached to the upper surface of the recess 17 by a screw 27.

Next, the operation of the paper feeding device 1 will be described. When the solenoid 12 does not operate, the frame feed member 8
Is at the initial position in the swinging motion of the frame feeding member 8, as shown in FIG. As shown in FIG. 4, the engagement claw 9 of the frame feed member 8 is engaged with the tooth portion 5 of the claw wheel 4 integrated with the paper feed roller 6 by the biasing force of the tension spring 11 and is opposed to the locking claw 9. The facing driven pawl 10 faces the tooth portion 5 of the ratchet wheel 4 and is separated therefrom.

At this time, since the pawl wheel 4 provided on the paper feed roller 6 is locked by the engagement of the locking pawl 9 provided on the frame feed member 8, the forward rotation of the paper is stopped. As the connecting end 7a side of the one-way clutch 7 shown in FIG. 2 is fixed, the position direction clutch 7 is loosened and the power transmission from the rotary shaft 3 is interrupted, and only the rotary shaft 3 is in the paper feeding direction indicated by the arrow a. Is driven to rotate.

The solenoid 12 is operated when the print paper is slightly fed. In addition, the operation of minute feeding is, for example,
The printer body (not shown) is provided with an operation panel equipped with a push switch so that the operator can manually perform the operation.

The solenoid 12 disengages the locking pawl 9 provided on the frame feed member 8 against the biasing force of the tension spring 11 and reversely engages the driven pawl 10 with the tooth portion 5 of the ratchet wheel 4. Later deactivated.

When the solenoid 12 operates, the armature 24 integral with the frame feeding member 8 is attracted to the solenoid 12 in FIG. 3, and the frame feeding member 8 swings around the support shaft 21 toward the arrow b side in FIG. Then, as shown in FIG. 5, the locking claw 9 provided on the frame feeding member 8 is disengaged from the tooth portion 5 of the ratchet wheel 4 provided on the paper feeding roller, and is also a driven claw facing the locking claw 9. 10 is engaged with the tooth portion 5 of the ratchet wheel 4.

When the engaging claw 9 is disengaged from the ratchet wheel 4, the one-way clutch 7 shown in FIG. 2 is released from the engaging end 7a, and the one-way clutch 7 is connected to the rotary shaft 3. As a result, power is transmitted and the rotary shaft 3, the ratchet wheel 4, and the paper feed roller 6 are about to rotate together in the paper feed direction indicated by the arrow a. However, as shown in FIG. 5, since the driven pawl 10 is engaged with the tooth portion 5 of the ratchet wheel 4,
The ratchet wheel 4 does not rotate rapidly and therefore the ratchet wheel 4
The pitch deviation of the tooth portion 5 of the above is prevented. At this time, the driven pawl 10 engaged with the tooth portion 5 of the ratchet wheel 4 is pressed by the surface 5 a of the tooth portion 5 of the ratchet wheel 4 on the rotation direction side by the rotational force of the ratchet wheel 4. That is, a force that pushes back the frame feeding member 8 to the initial position in swinging acts.

When the solenoid 12 is deenergized, the frame feed member 8 is moved to the initial position in the swing motion of the frame feed member 8 by the urging force of the tension spring 11 and the pressing force on the driven pawl 10 by the rotation of the ratchet wheel 4. While swinging, the rotary shaft 3, the ratchet 4 and the paper feed roller 6 shown in FIG.
Rotate in the paper feed direction indicated by. As a result, as shown in FIGS. 6 to 7, the driven claw 10 is disengaged from the tooth portion 5 of the ratchet wheel 4 and returned, and the locking claw 9 engages with the tooth portion 5 of the ratchet wheel 8 to cause the ratchet wheel 4 to move. The one-way clutch 7 shown in FIG.
Is cut off, and only the rotary shaft 3 is again driven to rotate in the paper feeding direction indicated by the arrow a.

At this time, the driven pawl 10 is set to the tooth portion 5 of the ratchet wheel 4.
By moving over the pitch, the ratchet wheel 4 rotates by one pitch,
Since the paper feed roller 6 is rotated by one pitch together with the ratchet wheel 4, the paper is fed by one pitch in the paper feeding direction.

[0036]

According to the paper feeding device of the printer of the present invention, the paper feeding roller, which is pivotally supported by the main body of the apparatus and has the pawl wheel on the rotary shaft which is always driven in the paper feeding direction, is placed between the rotary shaft and the paper feeding roller. It is mounted via a one-way clutch in which power is transmitted from the rotating shaft to the paper feed roller only when the feed roller is rotated in the forward direction for feeding the paper, and is engaged with a locking pawl that engages with the teeth of the ratchet wheel. A frame feed member integrally provided with a driven claw facing the stop claw is provided, the frame feed member is pivotally supported on the main body of the apparatus, and the locking claw and the driven claw are exposed to the teeth of the ratchet wheel. , And the biasing means for biasing the locking claw of the frame feed member to engage with the tooth portion of the ratchet wheel, and the locking claw is disengaged against the bias of the biasing means to reversely drive the driven claw. By providing the frame feed member driving means that is deenergized after being engaged with the sheet, When the stop claw is disengaged from the ratchet wheel, the driven claw engages with the tooth portion of the ratchet wheel to lock the rapid rotation of the ratchet wheel and prevent the tooth gap of the ratchet wheel from shifting. , It is possible to accurately realize minute feeding of the paper without causing the nail wheel to cause a pitch shift.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a paper feeding device of a printer according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part of FIG.

FIG. 3 is a side view showing an enlarged main part of FIG.

FIG. 4 is a side view showing the engagement relationship between the ratchet wheel and the frame feed member at an initial position.

FIG. 5 is a side view showing the engagement relationship between the ratchet wheel and the frame feed member in swinging the frame feed member.

FIG. 6 is a side view showing the engagement relationship between the ratchet wheel and the frame feed member in swinging the frame feed member.

FIG. 7 is a side view showing the engagement relationship between the ratchet wheel and the frame feed member in swinging the frame feed member.

[Explanation of symbols]

 1 Paper Feed Device 2 Paper Feed Device Main Body 3 Rotation Shaft 4 Claw Wheel 4a Shaft Insertion Hole 4b Spring Clutch Engagement Groove 5 Teeth 6 Paper Feed Roller 6a Support 6b Shaft Insertion Hole 6c Spring Clutch Engagement Groove 6d Annular Body 7 1 Directional clutch 7a Connection end 7b Connection end 8 Frame feed member 8a Curved part 8b Curved part 8c Central part 9 Locking claw 10 Followed claw 11 Tensile spring 12 Solenoid 15 Bottom plate part 16a Side plate 16b Side plate 17 Recessed part 18 Roller shaft 19 Friction roller 20 Support Body 21 Support shaft 22 Spring locking convex portion 23 Shaft hole 24 Armature 25 Spring locking convex portion 26 Yoke portion 27 Screw 28 Gear 29 E ring

Claims (1)

[Claims] 1. A paper feed roller, which is axially supported by a main body of the apparatus and has a pawl wheel on a rotary shaft which is constantly driven in the paper feed direction,
It is mounted via a one-way clutch in which power is transmitted from the rotary shaft to the paper feed roller only when the paper feed roller is rotated in the forward direction for feeding the paper between the rotary shaft and the rotary shaft. A frame feeding member integrally having a locking claw engaging with the locking claw and a driven claw facing the locking claw, the frame feeding member is pivotally supported on the apparatus main body side, and the locking claw is provided. And a biasing means for biasing the driven claw to face the tooth portion of the ratchet wheel and biasing the locking claw of the frame feed member to engage with the tooth portion of the ratchet wheel and the biasing means. A paper feeding device for a printer, characterized in that the frame feeding member drive means is provided which is deenergized after the locking claw is removed against the above and the driven claw is engaged with the tooth portion.