JP2004216862A - Thermal printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal printer which can connect a first and a second frames without using a special fastening member, and has a good operability, and of which the cost can be reduced. <P>SOLUTION: On the second frame 3 of this thermal printer 1, a supporting groove 7 which can support the rotating shaft 4a of a platen roller 4 being supported by the first frame 2 is formed. In the supporting groove 7, a locking part 8 which can lock the supported rotating shaft 4a is formed. When the rotating shaft 4a is engaged with the supporting groove 7 by sliding the first frame 2 to the second frame 3 side, the rotating shaft 4a is locked by the locking part 8, and the first frame 2 can be connected with the second frame 3. Therefore, the attaching/detaching of the first and second frames 2 and 3 is easy. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a thermal printer, and more particularly, to a thermal printer capable of printing a desired image on a recording medium by selectively causing a heating element of a thermal head to generate heat based on print information.

  In the conventional thermal printer, as shown in FIGS. 7 and 8, a first frame 51 supported by a main body case (not shown) and slidable in the direction of arrow A is provided. A rotation shaft 52a of a platen roller 52 is rotatably supported on the other side plate 51a, 51b, and a rotation shaft 52a protruding outside the one side plate 51a receives rotation from a drive source (not shown). A gear group 53 for transmitting to the platen roller 52 is attached. Further, hook-shaped lock claws 51c are formed on one side and the other side plates 51a, 51b of the first frame 51 so as to protrude upward.

A second frame 54 fixed to a main body case (not shown) is provided on the side facing the first frame 51, and the second frame 54 is slid in the direction of arrow A so that the second frame 54 is moved. It is detachable from the frame 54.
The second frame 54 is formed by bending the left and right ends of the top plate 54a downward to form one and the other side plates 54b and 5c, and the one and the other side plates 54b and 54c have guide projections 54d on the front side. 54e are formed.

The rotation shaft 52a of the platen roller 52 can be guided by the guide protrusions 54b and 54e. A release lever 55, which is a locking member with which the lock claw 51c of the first frame 51 can be engaged, is rotatably supported by the one and the other side plates 54b, 54c.
As shown in FIG. 6, the release lever 55 has a locking claw 55a formed at the left end, and is elastically urged counterclockwise by a torsion coil spring (not shown).
A paper storage portion of a slider (not shown) supported on the body case side together with the first frame 51 and slidable in the direction of arrow A, for example, a thermal roll wound in a roll shape as shown by a two-dot chain line. A recording medium 56 made of paper is stored.

The printing operation by such a conventional thermal printer will be described. The first frame 51 in a state where the recording medium 56 stored in the paper storage section is routed on the platen roller 52 is slid in the direction of arrow A.
Then, the recording medium 56 on the platen roller 52 is pressed by the thermal head and pressed against the platen roller 52, and the rotating shaft 52a of the platen roller 52 is guided by the guide protrusions 54d and 54e.
At the same time, the locking claw 51c is engaged with the locking claw 55a of the release lever 55, so that the first frame 51 is connected to the second frame 54 and the thermal head is pressed against the platen roller 52 via the recording medium 56. Then, the conventional thermal printer is set in a printing standby state.

In the printing standby state, the heating elements of the thermal head are selectively heated based on the printing information, and the recording medium 56 is conveyed in the discharge direction by rotating the platen roller 52 in the counterclockwise direction. A desired image can be printed on the recording medium 56.
After printing, the release lever 55, which is a locking member, is manually rotated clockwise against the biasing force of the torsion coil spring, and the locking claw 55a engaged with the locking claw 55c is rotated. The recording medium 56 is replaced or replenished by releasing the engagement and pulling out the first frame 51 in the direction opposite to the arrow A.
JP 2002-067435 A

However, in the conventional thermal printer described above, when the recording medium 56 is exchanged or replenished, the release lever 55 is manually rotated clockwise against the biasing force of the torsion coil spring, Since the connection between the first frame 51 and the second frame 54 had to be released, the operation was troublesome.
Further, in the conventional thermal printer, since the release lever 55 as a locking member is provided on one and the other side plates 54b and 54c, there is a problem that the number of parts increases and the cost increases.
The present invention solves the above-mentioned problems, and can connect the first and second frames without using a special locking member. The operability is good, the number of parts is small, and the cost can be reduced. It is an object to provide a thermal printer.

  As a first solution for solving the above-mentioned problems, a thermal printer according to the present invention includes a first frame supporting a rotating shaft of a platen roller, a second frame supporting a thermal head capable of being pressed against the platen roller, A body case to which the first frame is slidably supported and to which the second frame is attached, wherein a support groove capable of supporting the rotating shaft of the platen roller is formed in the second frame; The groove is provided with a retaining portion capable of retaining the supported rotation shaft, and the first frame is slid toward the second frame side to engage the rotation shaft with the support groove, whereby the rotation is prevented. A shaft is retained by the retaining portion so that the first frame can be connected to the second frame.

  As a second solution to solve the above problem, the support groove has one and the other guide surfaces facing each other with a predetermined gap therebetween, and the retaining portion is provided with the one guide. When the first frame is slid and connected to the second frame, the rotating shaft moves over the retaining portion and is positioned at a support portion on the back side of the support groove, and the thermal head is The rotating shaft is prevented from coming off from the support portion by a pressure contact pressure pressed against the platen roller.

  As a third solution for solving the above-described problem, the retaining portion is formed of a convex portion protruding from the one guide surface, and is provided between the top of the convex portion and the other guide surface. Is formed to be the same as or larger than the diameter of the rotating shaft.

  As a fourth solution for solving the above-mentioned problem, the retaining portion is characterized in that a foot portion of the convex portion is formed in a tapered shape.

  As a fifth solution for solving the above-mentioned problem, the support groove is formed such that the shape of the support portion on the back side is formed in an arc shape capable of rotatably supporting the rotation shaft. And

  As a sixth solution for solving the above-described problem, the other guide surface may be configured such that the rotation shaft that has passed over the retaining portion is positioned on the back side of a portion where the retaining portion is opposed to the circle. A guide portion capable of guiding the arc-shaped support portion is formed.

  In the thermal printer of the present invention, when the first frame is slid to the second frame side to engage the rotation shaft with the support groove, the rotation shaft is prevented from falling off by the retaining portion, and the first frame is connected to the second frame. Since the connection is possible, the connection with the second frame can be released only by pulling the first frame with a predetermined force, and the operability can be improved without operating the locking member as in the conventional example. Can provide a good thermal printer.

  Further, when the first frame is connected to the second frame, the rotating shaft is positioned at the support portion on the back side of the support groove over the retaining portion, and the rotating shaft is pressed by the pressing pressure at which the thermal head is pressed against the platen roller. Since it is prevented from falling off from the support portion, a special locking member as in the conventional example is not required, so that the cost can be reduced.

  Further, the retaining portion is formed of a convex portion protrudingly formed on one of the guide surfaces, and the gap between the top of the convex portion and the other guide surface is formed to be the same as or larger than the diameter of the rotating shaft. Therefore, the rotation shaft can be easily attached to and detached from the support groove.

  In addition, since the bottom portion of the convex portion is formed in a tapered shape in the retaining portion, the attachment and detachment of the rotating shaft is further facilitated.

  Also, since the shape of the support portion on the back side is formed in an arc shape capable of rotatably supporting the rotation shaft, the vibration of the rotation shaft in the support portion can be maintained even when externally guided. Can be prevented and high quality printing can be performed.

  In addition, the other guide surface has a guide portion formed on the back side of the portion where the stopper portion is opposed to the guide portion capable of guiding the rotating shaft that has passed over the stopper portion to the arc-shaped support portion. The rotating shaft over the portion can be reliably supported by the support portion.

  An embodiment of a thermal printer according to the present invention will be described below with reference to the drawings. First, FIG. 1 is a perspective view according to the first embodiment of the present invention, and FIG. 2 is a perspective view in which a second frame is connected to a first frame according to the first embodiment of the present invention. FIG. 3 is an enlarged view illustrating the support operation of the platen roller according to the first embodiment of the present invention, and FIG. 4 is an enlarged view of the platen roller according to the first embodiment of the present invention supported by a support portion. FIG. 5 is an enlarged view for explaining a supporting operation of the platen roller according to the second embodiment of the present invention, and FIG. 6 is a diagram showing a state where the platen roller according to the second embodiment of the present invention FIG.

First, as shown in FIG. 1, a thermal printer 1 according to a first embodiment of the present invention has a first frame 2 whose upper part is open, and a lower part which is open on the side facing the first frame 2. The second frame 3 is provided.
The second frame 3 is fixedly attached to a main body case (not shown) with screws or the like, and the first frame 2 is slidably supported by the main body case in the direction of the arrow B toward the second frame 3. ing.
The first frame 2 is formed by bending a metal plate to form one and the other side plates 2a and 2b facing each other, and a platen roller at a position near the upper end of the one and the other side plates 2a and 2b. The four rotating shafts 4a are rotatably supported.
The platen roller 4 is formed by fixing a roller portion 4b having a large coefficient of friction, such as hard rubber, to a rotating shaft 4a.

A disk 4c that can push up a head mounting base 10a, which will be described later, supported on the second frame 3 is fixed to both left and right ends of the rotating shaft 4a.
A gearbox 5 is attached to the other side plate 2b of the first frame 2 shown in FIG. 1, and a rotating shaft 4a protruding from the other side plate 2b and located in the gearbox 5 is provided with a motor or the like. A gear group 6 composed of a plurality of gears connected to a driving source (not shown) is attached, and rotation of the driving source can be transmitted to the platen roller 4 via the gear group 6.
Further, as shown in FIG. 1, the second frame 3 is formed by bending a metal plate, bending a top plate 3a on the upper surface, and bending left and right ends of the top plate 3a downward to face one and the other side plates. 3b and 3c are formed to form a U-shape whose lower part is open.

A substantially U-shaped support groove 7 is formed at the left end in the drawing of one and the other side plates 3b and 3c, and the rotation shaft 4a of the platen roller 4 can be rotatably supported in the support groove 7. ing.
As shown in FIGS. 3 and 4, the support groove 7 has one guide surface 7a formed on the lower side, and the other guide surface 7b formed on the upper side facing the one guide surface 7a. The dimension between one of the guide surfaces 7a and 7b is slightly larger than the diameter of the rotating shaft 4a of the platen roller 4.

Further, a back wall 7c is formed at the back of the support groove 7, and the rotating shaft 4a supported by the support groove 7 can be brought into contact with the back wall 7c.
On one guide surface 7a on the entrance side of the support groove 7, a retaining portion 8 capable of retaining the rotating shaft 4a supported by the support groove 7 is formed.
The retaining portion 8 is formed with a convex portion 8a projecting upward from the one guide surface 7a at a predetermined height, and the convex portion 8a has a first tapered surface 8b at a foot portion on the right side in the drawing and a left tapered surface on the left side in the drawing. A second tapered surface 8c is formed at the foot portion of the slab and has a mountain shape. The clearance D between the top of the retaining portion 8 and the other guide surface 7b is equal to or larger than the diameter of the rotating shaft 4a.
Further, the support groove 7 has a support portion 7d on the back side of the retaining portion 8 which is capable of retaining the rotation shaft 4a of the platen roller 4 and supporting the same.

As shown in FIGS. 3 and 4, a head mount 10a is elastically urged to the top plate 3a of the second frame 3 via an elastic member 9 such as a coil spring. The thermal head 10 is supported.
Although not shown, the head mounting base 10a is configured to contact the disc 4c of the platen roller 4 and push up the disc 4c, and the disc 4c is disengaged from the thermal head 10 so that the platen roller 4c is released. And a non-contact portion that can be pressed against the contact portion.

When the platen roller 4 slid in the direction of arrow B is located near the retaining portion 8, the disc 4c contacts the contact portion of the head mounting base 10a.
As a result, the thermal head 10 is pushed upward and separates from the roller portion 4b of the platen roller 4.
Further, when the platen roller is further pushed in the direction of arrow B and the rotating shaft 4a moves over the retaining portion 8 and is positioned on the support portion 7d, the disk 4c is positioned at the non-contact portion and the thermal head 10 is pushed up. It is released and comes into pressure contact with the platen roller 4.

The rotating shaft 4a is pressed against the one guide surface 7a by the pressure contact pressure of the thermal head 10 applied to the platen roller 4, and the rotating shaft 4a, which is prevented from falling off by the retaining portion 8, can be rotatably supported by the support portion 7d. It has become.
Further, on the right side of the first frame 2 in the figure, a paper storage unit (not shown) capable of storing a recording medium (not shown) made of, for example, a thermal paper wound in a roll shape is provided. The recording medium accommodated in the sheet accommodating section also slides along with the arrow in the direction of arrow B.
Further, an FPC 11 for controlling the energization of a plurality of heating elements of the thermal head 10 is drawn out from the rear side of the second frame 3.

The printing operation by the thermal printer 1 according to the first embodiment of the present invention will be described. First, as shown in FIG. 1, in a state where the first frame 2 is separated from the second frame 3, Store in the paper storage section. Thereafter, the end of the recording medium is routed on the platen roller 4.
In this state, the first frame 2 is slid in the direction of arrow B, and when the platen roller 4 is positioned at the entrance of the support groove 7, the disk 4c pivotally supported by the rotation shaft 4a of the platen roller 4 is moved to the head mounting base 10a. , The thermal head 10 is pushed upward.
As a result, the platen roller 4 does not collide with the thermal head 10 when sliding in the direction of arrow B.

When the platen roller 4 is positioned at the entrance of the support groove 7 and the first frame 2 is further pushed in the direction of arrow B, the rotating shaft 4a rides over the retaining portion 8 and as shown in FIG. It engages with the support 7d on the back side of the groove 7.
At this time, the disk 4c is located at the non-contact portion of the head mounting base 10a, and the lifting of the head mounting base 10a is released, and the thermal head 10 is pressed against the platen roller 4 via the recording medium. You.
Then, the rotating shaft 4a located at the support portion 7d is pressed against the one guide surface 7a by the pressing pressure at which the thermal head 10 is pressed against the platen roller 4.
As a result, the rotating shaft 4a is guided by the first tapered surface 8b of the retaining portion 8, is further pushed inward, and comes into contact with the inner wall 7c to be in a retaining state.
At the same time, as shown in FIG. 2, the first frame 2 is connected to the second frame 3 to be in a printing standby state.

When a print command is issued during this print standby state, a plurality of heating elements of the thermal head 10 are selectively heated based on the print information, so that a recording medium made of, for example, thermal paper is colored and the platen roller 4 is moved. By rotating in the counterclockwise direction, the recording medium is ejected in the direction of arrow C, and a desired image is printed on the recording medium.
When the recording medium is exchanged or replenished after printing is completed, a force is applied to the first frame 2 in the direction of arrow C so that the rotating shaft 4a passes over the retaining portion 8 and is pulled out of the support portion 7d. Then, the connection between the first and second frames 2 and 3 is released. Then, as shown in FIG. 1, a gap is formed between the first and second frames 2 and 3, and the recording medium can be replaced or replenished from this gap.

In the thermal printer 1 according to the first embodiment of the present invention, the first frame 2 is slid in the direction of arrow B to support the rotation shaft 4a of the platen roller 4 in the support groove 7, so that the platen roller 4 Is pressed against the thermal head 10 and the rotating shaft 4a is prevented from falling off by the stopper 8 so that the first frame 2 can be connected to the second frame 3 without using a locking member as in the conventional example. It is possible to reliably connect.
In the first embodiment of the present invention, the retaining portion 8 has been described as the convex portion 8a having the first and second tapered surfaces 8b and 8c. However, the convex portion 8a has the first and second convex portions. It may be formed in a step shape without the tapered surfaces 8b and 8c.

A thermal printer 21 according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. Since the platen roller 4 and the thermal head 10 are the same as those in the first embodiment, the same numbers are used. The detailed description is omitted.
First, the platen roller 4 is supported and disposed on the first frame 2. A thermal head 10 supported by a head mount 10a is elastically supported by an elastic member 9 on a top plate 23a of the second frame 23 on a side facing the platen roller.

A substantially U-shaped support groove 27 is formed in one and the other side plates 23b and 23c of the second frame 23, and the rotation shaft 4a of the platen roller 4 can be rotatably supported in the support groove 27. Has become.
The support groove 27 has one and the other guide surfaces 27a and 27b opposed to each other at the entrance side, and the gap dimension D between the one and the other guide surfaces 27a and 27b is determined by the rotation axis 4a of the platen roller 4. It is formed larger than the diameter dimension.

Further, an arc-shaped support portion 27c capable of rotatably supporting the rotating shaft 4a is formed on the back side of the support groove 27.
On one guide surface 27a on the entrance side of the support groove 27, a retaining portion 28 capable of retaining the rotating shaft 4a supported by the supporting portion 27c is formed.
The retaining portion 28 is formed of a convex portion having a predetermined height, and a skirt portion on the back side is formed in an arc shape which also serves as a part of the support portion 27c. The retaining portion 28 is formed such that a skirt portion on the entrance side is tapered.
The gap between the top of the retaining portion 28 and the other guide surface 27b is slightly larger than the diameter of the rotating shaft 4a.
Therefore, the rotating shaft 4a inserted into the support groove 27 can easily get over the retaining portion 28.

Further, the other guide surface 27b of the support groove 27 is formed with a tapered guide portion 27d deeper than a portion facing the retaining portion 28, and the rotating shaft that has passed over the retaining portion 28 by the guide portion 27d. 4a can be guided to the support portion 27c.
In the thermal printer 21 according to the second embodiment, the first frame 2 is slid in the direction of arrow B to insert the rotation shaft 4a of the pre-tension roller 4 into the support groove 27.

At this time, the platen roller 4 moves the thermal head 10 upward by the rotating plate 4c against the urging force of the elastic member 9 to separate the thermal head 10 from the roller portion 4b, and the rotating shaft 4a is positioned on the one guide surface 27a. And slide to the back of the support groove 27.
The rotating shaft 4a rides over the retaining portion 28 and is guided by the guide portion 27d to be located on the arc-shaped support portion 27c.
At the same time, the lifting of the thermal head 10 by the rotating plate 4c is released, and the thermal head 10 descends and presses against the roller portion 4b of the platen roller 4 via a recording medium (not shown).

Thereafter, the recording medium is printed on the recording medium by the thermal head 10, and the recording medium after the printing is discharged in the left direction in the figure by rotating the platen roller 4 in the counterclockwise direction.
In the thermal printer 21 according to the second embodiment, since the rotating shaft 4a during printing is supported by the arc-shaped support portion 7c, even if vibration or the like is applied from outside during printing, the platen roller 4 can be prevented from vibrating independently, and the printing quality can be improved.

It is a perspective view concerning a 1st embodiment of the present invention. It is the perspective view which connected the 2nd frame to the 1st frame concerning a 1st embodiment of the present invention. FIG. 4 is an enlarged view illustrating a support operation of the platen roller according to the first embodiment of the present invention. FIG. 2 is an enlarged view of the platen roller according to the first embodiment of the present invention supported on a support unit. It is an enlarged view explaining support operation of a platen roller concerning a 2nd embodiment of the present invention. FIG. 11 is an enlarged view of a platen roller according to a second embodiment of the present invention supported on a support unit. FIG. 9 is an exploded perspective view illustrating a conventional thermal printer. FIG. 9 is a perspective view illustrating a conventional thermal printer.

Explanation of reference numerals

1: Thermal printer of the first embodiment 2: First frame 3: Second frame 4: Platen roller 4a: Rotating shaft 5: Gear box 6: Gear group 7: Support groove 7a: One guide surface 7b: The other 8: retaining portion 8a: convex portion 8b: first tapered surface 8c: second tapered surface 9: elastic member 10: thermal head 10a: head mount 11: FPC
21: Thermal Printer of Second Embodiment

Claims (6)

A first frame supporting a rotation shaft of a platen roller, a second frame supporting a thermal head capable of being pressed against the platen roller, and a main body case supporting the first frame slidably and mounting the second frame A support groove capable of supporting the rotation shaft of the platen roller is formed in the second frame, and a retaining portion capable of retaining the supported rotation shaft is formed in the support groove. When the first frame is slid toward the second frame and the rotating shaft is engaged with the support groove, the rotating shaft is prevented from falling off by the retaining portion, and the first frame is moved to the second frame. A thermal printer which can be connected to a frame. The support groove has one and the other guide surfaces facing each other with a predetermined gap therebetween, and the retaining portion is formed on the one guide surface, and slides the first frame to form the second frame. When connected to the frame, the rotating shaft moves over the retaining portion and is located at the support portion on the back side of the support groove, and the thermal shaft presses the platen roller so that the rotating shaft is 2. The thermal printer according to claim 1, wherein the thermal printer is prevented from falling off. The retaining portion is formed of a convex portion protruding from the one guide surface, and a gap between the top of the convex portion and the other guide surface is the same as or larger than the diameter of the rotating shaft. The thermal printer according to claim 1, wherein the thermal printer is formed. 4. The thermal printer according to claim 3, wherein the retaining portion has a skirt portion of the convex portion formed in a tapered shape. 4. The thermal printer according to claim 2, wherein the support groove on the back side is formed in an arc shape in which the shape of the support portion on the back side is capable of rotatably supporting the rotation shaft. 5. On the other guide surface, a guide portion is formed on the back side of a portion facing the retaining portion, the guide portion being capable of guiding the rotating shaft having passed over the retaining portion to the arc-shaped support portion. The thermal printer according to claim 5, wherein:

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