JP2002144660A - Printer and spring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively and properly utilize the spring force of the spring device mounted on a printer in the acceleration and deceleration of a printing unit without generating trouble such that the reciprocal operation of the printing unit becomes different from originally scheduled operation. SOLUTION: The spring device A is equipped with a first sleeve 51 for externally fitting the spring device to the guide shaft 6 of the printer, a pair of the second sleeves 52 fitted to both ends in the axial direction of the first sleeve 51 in a freely slidable manner and an elastic member 53 of which both ends are held by a pair of the second sleeves 52 and which has elastic force for protruding one ends of the second sleeves 52 toward the lateral direction of both ends in the axial direction of the first sleeve 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer of the type which prints on a recording paper while reciprocating a printing unit having a print head at a predetermined stroke in the width direction of the recording paper, and is used by being incorporated in the printer. The present invention relates to a spring device suitable for performing the above.

[0002]

2. Description of the Related Art Conventionally, an example of a printer is disclosed in
000-43360. In this printer, as shown in FIG. 6, a printing unit 90 is reciprocally movable in a longitudinal direction of a guide shaft 92 by a driving force of a linear motor 91. However, this printer is provided with a counter balancer 93 that reverses the reciprocating operation between the movable unit 91a of the linear motor 91 and the printing unit 90. This counter balancer 93
Is provided with, for example, a belt mechanism. When the movable portion 91a moves to the left of the arrow Na and the lower portion of the belt 93a moves in the same direction, the upper portion of the belt 93a and the printing unit 90 Moves to the right of the opposite arrow Nb. According to such a configuration, by balancing the weight movement of the printing unit 90 and the movable portion 91a, it is possible to prevent a large vibration from occurring in the printer.

In the above printer, a pair of guide portions 94 and an auxiliary member 95 of a printing unit 90 are externally fitted to a guide shaft 92, and a spring device 8 is provided between each of them. The auxiliary member 95 reciprocates at the same speed as the printing unit 90 and in the opposite phase by the driving force of the linear motor 91. According to such a configuration, when the printing unit 90 reciprocates and approaches the end of the reciprocating region, the spring of the spring device 8 is moved between one of the pair of guide portions 94 and the auxiliary member 95. Compressed. Therefore, the printing unit 90 can be decelerated using the resistance of the spring. After the printing unit 90 has completed the reversing operation at the end of the reciprocating region, the printing unit 90 can be accelerated by the restoring force of the spring. Thus, the printing unit 9
If the spring force of the spring device 8 is used for acceleration / deceleration of 0, the load on the linear motor 91 can be reduced as compared with the case where the printing unit 90 is reciprocated only by the driving force of the linear motor 91.

In the above-mentioned Japanese Patent Application Laid-Open No. 2000-43360, a spring device 8 is provided as means for reducing noise when the guide portion 94 and the auxiliary member 95 collide with the spring device 8.
A means has been proposed for disposing at a central portion between the guide portion 94 and the auxiliary member 95. When the spring device 8 is fixed to the guide portion 94, for example, the spring device 8 and the auxiliary member 9 are fixed.
According to the above-described means, the collision speed of the guide unit 94 and the auxiliary member 95 with respect to the spring device 8 is determined by the moving speed of the printing unit 90. And the noise can be reduced accordingly.

In the means described in the above publication, the structure of the spring device 8 is, for example, as shown in FIG. 7 in order to take measures against the noise. That is, the spring device 8
It comprises a pair of sleeves 80 slidably fitted on the guide shaft 92 and a coil spring 81 sandwiched between the sleeves 80. A slit 82 is provided in the small diameter portion 80a on the inner end side of each sleeve 80, and an elastic ring 83 is attached to the small diameter portion 80a.
“a” is configured to be pressed against the outer peripheral surface of the guide shaft 92 with an appropriate force.

[0006]

However, the above-mentioned conventional means has the following disadvantages.

That is, the spring device 8 is provided in each sleeve 80
By generating a certain frictional force between the spring device 8 and the guide shaft 92, the spring device 8 is to be held at a certain place. However, this spring device 8 is
Each sleeve 80 slides with respect to the guide shaft 92 when compressed by being sandwiched between the support member 4 and the auxiliary member 95. Also, each sleeve 80 slides when the compressed spring device 8 returns to its original state. Therefore, in the related art, when the spring device 8 expands and contracts, the respective sleeves 80 slide smoothly, and at other times, the mutually contradictory requirements that the respective sleeves 80 must be arranged at a fixed position are required.
It is not easy to satisfy such requirements. In particular, the frictional force between each sleeve 80 and the guide shaft 92 changes due to a change in the tightening force of the elastic ring 83, wear of the inner peripheral surface of each sleeve 80, the surface of the guide shaft 92, and the like. Meeting the requirements is more difficult.

Conventionally, when the frictional force between the guide shaft 92 and each of the sleeves 80 is large and when the frictional force is small, the resistance of the spring device 8 to the printing unit 90 is different. Operation was affected. The printer has a printing unit 90
Is generally configured to feed the recording paper when performing the reversing operation near the end of the reciprocating region, and to perform printing on the recording paper at other times.
Therefore, in the related art, there is a case where it is difficult to perform appropriate printing on the recording paper because the reversing operation of the printing unit 90 is different from the originally expected operation. Further, in the related art, when the frictional force between the guide shaft 92 and each of the sleeves 80 becomes insufficient, for example, the spring device 8 is easily displaced from the central portion between the guide portion 94 and the auxiliary member 95. If there is such a displacement, one of the guide portion 94 and the auxiliary member 95 hits one end of the spring device 8 earlier than the other, so that
The spring device 8 is flipped toward the other side. Then, the spring device A is further repelled by the other, and collides with each of the guide portion 94 and the auxiliary member 95 multiple times. Such multiple collisions cause a large amount of noise and need to be avoided.

The present invention has been conceived under such circumstances, and has a disadvantage that the reciprocating operation of the printing unit is different from the originally expected operation or that a loud noise is generated. Without causing
It is an object of the present invention to provide a printer that can effectively and appropriately use the spring force of a spring device for acceleration and deceleration of a printing unit. Another object of the present invention is to provide a spring device suitable for realizing such a printer.

[0010]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

A printer provided according to a first aspect of the present invention has a printing unit having a guide portion externally fitted on a guide shaft extending in a predetermined direction, and reciprocates the printing unit in the longitudinal direction of the guide shaft. A linear motor having a movable portion capable of reciprocating; a counter balancer for reversing the reciprocating operation between the movable portion of the linear motor and the printing unit; and a counterbalance fitted externally to the guide shaft, and An auxiliary member that reciprocates in the opposite direction to the printing unit in the longitudinal direction, and a spring device mounted on the guide shaft so as to be sandwiched between the auxiliary member and the guide unit of the printing unit. Wherein the spring device comprises: a first sleeve externally fitted to the guide shaft; and a first sleeve. A pair of second sleeves slidably fitted to both ends of the sleeve in the axial direction, both ends of which are sandwiched by the pair of second sleeves, and one end of each of the second sleeves is connected to the first sleeve by the first sleeve. And a resilient member having a resilient force to protrude toward both sides in the axial direction of the sleeve in the axial direction.

In the present invention, when the printing unit moves from a position near the end of the reciprocating movement region toward the end, and the spring device is sandwiched between the guide portion and the auxiliary member and compressed, the spring unit is moved. Each of the pair of second sleeves of the device compresses the elastic member while sliding toward the longitudinal center of the first sleeve. At this time, the resistance of the elastic member serves to decelerate the printing unit. Next, when the printing unit is inverted at the end of the reciprocating region and the distance between the guide portion and the auxiliary member is widened, the pair of second sleeves exerts a resiliency on which the elastic member attempts to expand. As a result, the first sleeve slides in a direction protruding from both ends in the longitudinal direction. The force at that time serves as a force for accelerating the guide portion and the auxiliary member in their traveling directions.

As described above, according to the present invention, each of the second sleeves is relatively moved with respect to the first sleeve both when the spring device is compressed and when the spring device returns to the original state. By sliding, the elastic member can be appropriately expanded and contracted, and it is not necessary to move the first sleeve. In the present invention, by fixing the first sleeve on the guide shaft, it is possible to prevent the entire spring device from being easily displaced from a predetermined position. Therefore, in the present invention, the spring device repeats multiple collisions between the guide portion and the auxiliary member due to the displacement of the spring device from the central portion between the guide portion and the auxiliary member. Does not occur.

Further, in the present invention, it is not necessary to generate a frictional force between the second sleeves and the guide shaft for fixing the entire spring device. Therefore, it is not necessary to strictly define the fitting dimensions of the second sleeve and the guide shaft so as to generate a predetermined frictional force, and the manufacturing is facilitated.

Further, in the present invention, each of the second
In addition to preventing wear of the sleeve and the guide shaft, the resistance of each of the second sleeves when the printing unit is decelerated due to a change in the surface state of the guide shaft or the like. It is also possible to prevent large fluctuations in force and the like. Therefore, the reversing operation of the printing unit can be stabilized, and the printing processing operation of the printer can be made appropriate.

In a preferred embodiment of the present invention, the first sleeve is configured to have a resilient force for tightening the outer periphery of the guide shaft.

According to such a configuration, the first sleeve can be stably fixed to the guide shaft. When necessary, the first sleeve can be forcibly moved in the longitudinal direction of the guide shaft, which is convenient when a spring device is positioned at a predetermined position of the guide shaft.

In another preferred embodiment of the present invention, the first sleeve has a substantially C-shaped cross section having a notch extending in the axial direction, and in a natural state detached from the guide shaft. , Are formed so as to have an inner diameter smaller than the outer diameter of the guide shaft.

According to such a configuration, the outer periphery of the guide shaft can be tightened with an appropriate elasticity while the first sleeve has a simple structure.

In another preferred embodiment of the present invention, the first sleeve and the second sleeve are arranged so as to prevent the second sleeve from projecting beyond a predetermined dimension from the first sleeve. Engagement means are provided that can engage with each other.

According to such a configuration, each of the second sleeves can be prevented from being unduly removed from the first sleeve.

In another preferred embodiment of the present invention, a portion of each of the second sleeves facing the auxiliary member or the guide portion of the printing unit has a higher elastic modulus than each of the second sleeves. A small cushioning material is provided. Here, the “elastic modulus” is a value obtained by dividing stress by strain, and a material having a smaller value has a larger deformation under a constant load.

According to such a configuration, the impact when the auxiliary member or the guide portion collides with the spring device can be reduced, and each portion can be protected and noise can be suppressed.

In the spring device provided by the second aspect of the present invention, a first sleeve for externally fitting to a desired shaft is slidably fitted to both ends of the first sleeve in the axial direction. A pair of second sleeves, both ends of which are sandwiched by the pair of second sleeves, and one end of each of the second sleeves projecting toward the side of both ends in the axial length direction of the first sleeve. And an elastic member having an elastic force.

According to the spring device having such a configuration, it is useful for realizing the printer intended by the present invention, and the same effects as those described for the printer provided by the first aspect of the present invention can be expected.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIGS. 1 and 2 show an example of a printer according to the present invention. 3 to 5 correspond to FIGS.
3 shows a spring device mounted on the printer shown in FIG.

As is well shown in FIG. 1, the printer P of this embodiment is configured as a dot impact printer, and the basic configuration except for the spring device A mounted on the printer P is as follows. This is almost the same as the printer described in the related art. Specifically, the printer P includes a printing unit 1, a counter balancer 2, a linear motor 3, a pair of auxiliary members 4, and a pair of spring devices A.

The printing unit 1 is generally called a hammer bank, and as shown in FIG.
Dot impact print head 1 as print hammer
An appropriate number of 0s is provided. A platen roller 70 is provided at a position facing the print head 10, and the recording paper K is configured to be conveyed therebetween. As shown in FIG. 1, a pair of guide portions 11 are provided at both ends in the longitudinal direction of the printing unit 1.
These guide portions 11 are slidably fitted on the guide shaft 6 extending in the horizontal direction.

The pair of auxiliary members 4 are slidably fitted on the guide shaft 6 so as to be located between the pair of guide portions 11 of the printing unit 1. Spring device A
Is mounted on the guide shaft 6 so as to be located between each auxiliary member 4 and each guide portion 11. Spring device A
The specific configuration will be described later.

The linear motor 3 comprises, for example, a movable portion 30 having a plurality of electromagnetic coils and a stator 31 having a plurality of magnets (permanent magnets). The thrust is generated in the movable portion 30 based on Fleming's left-hand rule. The movable section 30 is reciprocally movable with a constant stroke. Note that, unlike the present embodiment, a configuration may be adopted in which the movable section 30 has a magnet and the stator 31 has an electromagnetic coil.

The counter balancer 2 has a belt mechanism as in the above-mentioned prior art. In this belt mechanism, a belt 21 is wound around a pair of pulleys 20a and 20b, and a lower portion of the belt 21 is connected to a movable portion 30 of the linear motor 3 and a pair of auxiliary members 4 via a connecting member 22.
It is connected (rigidly connected) to The upper part of the belt 21 is connected to the printing unit 1 via a connecting member 23.
For this reason, when the movable part 30 reciprocates left and right in FIG. 1, the pair of auxiliary members 4 also move by the same amount in the same direction. On the other hand, the reciprocating operation of the printing unit 1 is configured to move in a phase opposite to that of the movable unit 30 and each auxiliary member 4, that is, to move in a direction opposite to the movable unit 30 and each auxiliary member 4.

Each spring device A includes a first sleeve 51, a pair of second sleeves 52,
And a spring 53 as an elastic member.

The first sleeve 51 is made of a flexible synthetic resin, and has a substantially C-shaped cross section having a notch 51a as best seen in FIG. The notch 51a is
The first sleeve 51 is provided along the entire length region in the axial length direction. For this reason, the first sleeve 51 is freely expandable and contractible in the radial direction. This first sleeve 5
4 is formed such that its inner diameter D2 is smaller than the outer diameter D1 of the guide shaft 6 in a natural state where it is not fitted to the guide shaft 6 as indicated by a virtual line in FIG. The first sleeve 51 is externally fitted to the guide shaft 6 in a state where its radius is larger than the above-mentioned natural state.

Each second sleeve 52 includes a first sleeve 51
The first sleeve 51 is slidably fitted to both ends of the first sleeve 51 in the axial length direction. The fitting of the second sleeve 52 to the first sleeve 51 and the guide shaft 6 is relatively loose. Thereby, the guide shaft 6 and the first sleeve 51
And the frictional force generated between the guide shaft 6 and the second sleeve 52 and the frictional force generated between the first shaft 51 and the second sleeve 52 regardless of the change in the surface state of the guide shaft 6. It is made to be larger than the frictional force generated between them.

The inner end of each second sleeve 52 in the axial direction (the end of the first sleeve 51 near the center in the axial direction) is provided with the first
A protrusion 52b is provided which can be engaged with a protrusion 51b provided on the outer peripheral surface of both ends in the axial direction of the sleeve 51. These protrusions 51b and 52b correspond to an example of the engagement means in the present invention. A flange 52a is provided at the axially outer end of each of the second sleeves 52. The outward facing surface of the flange 52a has a smaller elastic modulus than each of the second sleeves 52 (for example, urethane rubber). ) A sheet-like cushioning material 54 is provided.

The spring 53 is, for example, a compression coil spring made of metal, and includes the first sleeve 51 and the second sleeves 5.
2 is loosely fitted to the outside of the housing 2 and is sandwiched between a pair of flanges 52a. As shown in FIG. 3, the spring device A is in a normal state where no load is applied from outside.
When each flange 52a receives the elastic force of the spring 53, the outer end of each second sleeve 52 projects to the side of the longitudinal end of the first sleeve 51. In this state, the second sleeves 52 do not come off from the first sleeve 51 because the convex portions 51b and 52b abut each other and engage with each other.

Next, the operation of the printer P having the above configuration will be described.

When the printer P is operated, each spring device A is previously arranged at a central portion between each guide section 11 of the printing unit 1 and each auxiliary member 4. Each spring device A
Although the first sleeve 51 is in a state where the guide shaft 6 is tightened with a constant elastic force, it can be slid in the longitudinal direction of the guide shaft 6 by applying a relatively large force. Therefore, the spring device A can be easily positioned.

When the linear motor 3 is driven and the printing unit 1 moves, for example, to the right in FIG. 1, the guide part 11 at the left end of the printing unit 1 and the corresponding auxiliary member 4 come close to each other. Become. Therefore, the guide portion 11 and the auxiliary member 4 come into contact with both ends of the spring device A located therebetween, and the spring device A is pressed in the direction of the arrow N1 in FIG. 3 from both sides thereof. Then, each second sleeve 52 of the spring device A slides toward the central portion in the longitudinal direction of the first sleeve 51 while compressing the spring 53. At this time, the resistance force of the spring 53 serves as an auxiliary force for decelerating the printing unit 1, and the load on the linear motor 3 when decelerating the printing unit 1 near the end is reduced. When the guide portion 11 and the auxiliary member 4 come into contact with the spring device A, they come into contact with the cushioning material 54 having a smaller elastic modulus than each of the second sleeves 52, so that the impact at that time is reduced and the generation of noise is reduced. It can also be suppressed. When the printing unit 1 reaches the right end of the reciprocating region, the spring device A is in the state shown in FIG.

Next, when the printing unit 1 is turned over, the guide portion 11 and the auxiliary member 4 move in directions away from each other (the direction of the arrow N2 in FIG. 5). At this time, the pair of second sleeves 52 slide so as to protrude to the side of both ends in the longitudinal direction of the first sleeve 51 by the resilience F of the spring 53, and move the guide portion 11 and the auxiliary member 4 to advance the Bias in the direction. This urging force is applied to the printing unit 1
, And the load on the linear motor 3 when the print unit 1 is reversed and then accelerated is reduced. When the distance between the guide portion 11 and the auxiliary member 4 increases, the spring device A returns to the original state shown in FIG.
When the printing unit 1 moves to the left in FIG. 1 and is turned over, the above-mentioned spring device A is interposed between the guide unit 11 at the right end of the printing unit 1 and the corresponding auxiliary member 4. The same operation as described above can be obtained.

In the compression operation and the return operation of the spring device A, each second sleeve 52 slides relative to the first sleeve 51 while expanding and contracting the spring 53. On the other hand, the first sleeve 51 does not move. Therefore, the spring device A does not shift from the center between the guide portion 11 and the auxiliary member 4. Spring device A
Is displaced from the central portion, one of the guide portion 11 and the auxiliary member 4 collides with one end of the spring device A prior to the other, and pushes the spring device A to the other side. A phenomenon in which the whole reciprocates on the guide shaft 6 in an unstable manner occurs, but in the present embodiment, such a phenomenon can be prevented.

Each second sleeve 52 has a guide shaft 6
And the first sleeve 51 are loosely fitted to each other, so that these parts can be hardly worn. Further, even if the surface condition of the guide shaft 6 is slightly changed due to wear of the guide shaft 6 or the diameter of the guide shaft 6 is slightly increased due to a temperature rise, the second sleeves 52 are not removed. It is also possible to prevent a large fluctuation in the frictional force when moving in the longitudinal direction of the guide shaft 6. Therefore, the resistance of each second sleeve 52 when the spring device A is compressed by the guide portion 11 and the auxiliary member 4, and each second sleeve 52 when the spring device A returns from the compressed state to the original non-compressed state. Therefore, the respective forces for urging the guide portion 11 and the auxiliary member 4 are also constant, and the overall reciprocating operation including acceleration and deceleration of the printing unit 1 is stabilized. Therefore, by stabilizing the reciprocating operation of the printing unit 1, an appropriate printing process on the recording paper is also achieved.

The specific configuration of each part of the printer and the spring device according to the present invention is not limited to the above-described embodiment, and various design changes can be made.

Regarding the first sleeve of the spring device, the first sleeve
For example, an elastic ring is externally fitted to the first sleeve instead of providing the elasticity to the sleeve itself, and the first sleeve is pressed against the outer peripheral surface of the guide shaft by using the elasticity of the elastic ring. It may be configured as follows. Further, after the first sleeve is formed in a tubular shape that is loosely fitted to the guide shaft, the first sleeve can be positioned and fixed at a predetermined position on the guide shaft by using a means such as a set screw. I don't care.

As the elastic member provided in the spring device, various other elastic members can be used instead of the metal compression coil spring, and the specific type is not limited.

The printing unit of the printer according to the present invention is not limited to one having a dot impact type printing head. For example, a print head of a thermal type or an ink jet type may be provided.
The counter balancer may be of any type as long as it has a function of making the reciprocating operation between the movable portion of the linear motor and the printing unit reverse in phase. The printer according to the present invention may have a structure in which one auxiliary member is provided at an intermediate portion between a pair of guide portions as shown in FIG. 6 of the related art. The specific number is not limited.

[0049]

As will be understood from the above description, according to the printer of the present invention, the reciprocating operation of the printing unit is different from the originally expected operation,
Alternatively, the spring force of the spring device can be effectively and appropriately used for accelerating and decelerating the printing unit without causing a problem such as generating a loud noise due to repeated collision of the spring device. Further, the spring device according to the present invention can be used to realize the printer according to the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing an example of a printer according to the present invention.

FIG. 2 is a schematic side view of the printer shown in FIG.

FIG. 3 is a sectional view of a spring device mounted on the printer shown in FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a sectional view showing a compressed state of the spring device.

FIG. 6 is a front view illustrating an example of a conventional printer.

FIG. 7 is a sectional view showing an example of a conventional spring device.

[Explanation of symbols]

 P Printer A Spring device 1 Printing unit 2 Counter balancer 3 Linear motor 4 Auxiliary member 6 Guide shaft 10 Print head 11 Guide part 30 Movable part 51 First sleeve 51a Notch part 51b Convex part 52 Second sleeve 52b Convex part 53 Spring (elasticity) Member) 54 cushioning material

Claims (6)

[Claims] 1. A linear motor having a printing unit having a guide part externally fitted on a guide shaft extending in a predetermined direction, and a reciprocating movable part for reciprocating the printing unit in a longitudinal direction of the guide shaft. A counter balancer that reverses the reciprocating operation between the movable portion of the linear motor and the printing unit; and a counter balancer that is externally fitted to the guide shaft and reciprocates in the longitudinal direction of the guide shaft with the printing unit in reverse phase. A printer, comprising: an auxiliary member for performing movement; and a spring device mounted on the guide shaft so as to be sandwiched between the auxiliary member and the guide portion of the printing unit. The spring device includes a first spring fitted on the guide shaft.
A sleeve, a pair of second sleeves slidably fitted to both ends of the first sleeve in the axial direction, and both ends sandwiched by the pair of second sleeves, and one end of each of the second sleeves An elastic member having a resilient force for projecting the portion toward the side of both ends in the axial length direction of the first sleeve.
Printer. 2. The printer according to claim 1, wherein the first sleeve has a resilient force for tightening an outer periphery of the guide shaft. 3. The first sleeve has a substantially C-shaped cross section having a cutout extending in the axial direction, and is smaller than the outer diameter of the guide shaft in a natural state where the first sleeve is removed from the guide shaft. 3. The printer according to claim 2, wherein the printer is formed to have an inner diameter. 4. The first sleeve and each of the second sleeves are provided with engagement means engageable with each other so as to prevent each of the second sleeves from projecting beyond a predetermined dimension from the first sleeve. The printer according to any one of claims 1 to 3, wherein the printer is provided. 5. A cushioning material having a smaller elastic modulus than each of the second sleeves is provided in a portion of each of the second sleeves facing the auxiliary member or the guide portion of the printing unit. Item 5. The printer according to any one of Items 1 to 4. 6. A first shaft for externally fitting to a desired shaft.
A sleeve, a pair of second sleeves slidably fitted to both ends of the first sleeve in the axial length direction, and both ends sandwiched by the pair of second sleeves, and one end of each of the second sleeves A resilient member having a resilient force for projecting the portion toward the side of both ends in the axial length direction of the first sleeve.