JPH0611819Y2 - Printer head retractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a device for retracting a print head from a platen in a printer when replacing a ribbon cassette or performing maintenance work.

[Prior Art] In a line thermal printer, printing is performed while the print head is pressed against the platen. Therefore, when replacing the ribbon cassette, it is necessary to form a gap between the platen and the print head. There is. As a method of forming a gap between the platen and the print head, a method of retracting the print head from the platen or a method of retracting the platen from the print head is known.

For example, as a structure for retracting the print head with respect to the platen, conventionally, as shown in FIG. 5, the thermal head 2 is pressed against the platen 1 by rotating the cam 6 from the position of the chain line to the position of the solid line. The thermal head 2 is retracted from the platen 1 by rotating the cam 6 from the position indicated by the solid line to the position indicated by the chain line.

That is, when the cam 6 is rotated from the position indicated by the chain line to the position indicated by the solid line, the pressure contact plate 5 is rotated clockwise about the support shaft 4 as a fulcrum in FIG. Then, since the mounting plate 3 is also rotated in the same direction via the spring 7, the thermal head 2 is pressed against the platen 1. Therefore, printing is performed in this state.
On the other hand, when the cam 6 is rotated from the position indicated by the solid line to the position indicated by the broken line, the spring 7 causes the pressure contact plate 5 to rotate counterclockwise in FIG. Then, the repulsive force of the spring 7 does not act on the mounting plate 3, so that the mounting plate 3 is rotated counterclockwise in FIG. Evacuated. Therefore, since a gap is formed between the platen 1 and the thermal head 2, the ribbon cassette is replaced in this state.

[Problems to be Solved by the Invention] In the structure shown in FIG. 5, since the thermal head 2 is pressed against the platen 1 and retracted by the cam 6, the retracted amount of the thermal head 2 relative to the platen 1 is reduced. Can't be big. That is, it is impossible to make a large gap between the platen 1 and the thermal head 2.

Therefore, there is a drawback that the replacement work of the ribbon cassette is troublesome and time-consuming, and that maintenance work, for example, cleaning the heating surface of the thermal head 2 and the peripheral surface of the platen 1 is difficult.

The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks. The ribbon cassette replacement work and maintenance work can be easily performed, and the ribbon cassette replacement work and maintenance work work can be easily performed. Another object of the present invention is to provide a head retracting device for a printer that can distinguish the above.

[Means for Solving Problems] Therefore, in the present invention, the print head has an engaging portion, and the print head approaches the platen with the first axis parallel to the platen as a fulcrum on the base plate. A mounting member rotatably provided in a separating direction, a first urging unit that urges the mounting member to rotate in a direction in which the print head is separated from the platen, and an operation lever, A supporting member whose base end is rotatably supported by a second shaft parallel to the first shaft as a fulcrum on the base plate, and a direction in which a tip end of the supporting member approaches the mounting member. Second urging means for urging the support member to rotate, and the first urging means engages with the engaging portion of the mounting member with the support member in a print attitude of the support member. The rotation of the mounting member by the biasing means is prevented, and the operation lever is The first locking portion, which is disengaged from the engaging portion when operated against the biasing means, and the mounting member rotated by a predetermined angle in a direction in which the print head is separated from the platen. At this time, the mounting member is engaged with the engaging portion of the mounting member to prevent rotation of the mounting member by the first biasing means, the mounting member is rotated against the first biasing means, and the operation lever is moved to the second position. A second locking portion that is disengaged from the engaging portion when operated against the biasing means of
When the mounting member rotates in a direction away from the platen over a certain angle, the mounting member engages with the engaging portion of the mounting member to prevent rotation of the mounting member by the first biasing means. The third locking portion is formed respectively.

[Operation] The operating lever is operated against the second urging means from a state in which the engaging portion of the mounting member and the first locking portion of the supporting member are engaged, that is, the print head is in the print posture. Then, the engagement between the engagement portion and the first locking portion is released, so that the mounting member is rotated by the first biasing means in the direction in which the print head is separated from the platen. Eventually, when the attachment member rotates in the same direction by a certain angle, the engagement portion and the second locking portion engage with each other, and the rotation of the attachment member is blocked. Therefore, the ribbon cassette can be replaced in this state.

From this state, when the mounting member is rotated against the first urging means and the operation lever is operated against the second urging means, the engaging portion and the second locking portion are separated from each other. Since the engagement is released, the mounting member is rotated by the first biasing means in the direction in which the print head is separated from the platen. Then,
The engaging portion and the third locking portion engage with each other, and rotation of the mounting member is blocked. Therefore, in this state, the mounting member is further rotated from the replacement position of the ribbon cassette, and the gap between the platen and the print head is large, so that the cleaning work of the print head and the platen can be easily performed. Moreover, only the operation lever is operated when exchanging the ribbon cassette, but since rotation operation of the mounting member and operation of the operation lever are required during maintenance work, the operation when exchanging the ribbon cassette and the maintenance work is required. Can be distinguished.

[Embodiment] The first embodiment of the present invention applied to a ticket issuing printer will be described below.
This will be described with reference to FIGS.

In FIG. 4, 11 is a platen, and 12 is a thermal head as a print head. The platen 11 has a structure that can be moved to the right in the figure from the state shown in the figure (printing standby state) to the state in which it is pressed against the thermal head 12 (printing state). An ink ribbon 14 drawn from a ribbon cassette 13 is inserted between the platen 11 and the thermal head 12, and the ink ribbon 14 is also inserted.
The ticket paper 15 is fed between the platen 11 and the platen 11 from obliquely above in the drawing. Therefore, if the thermal head 12 is operated while the ticket paper 15 is fed, it is possible to perform a predetermined printing on the ticket paper 15. Also,
The thermal head 12 is rotated by the head retracting mechanism 16 in the direction of retracting from the platen 11, and is positioned at the ribbon cassette replacement position and the cleaning position, respectively. Reference numeral 17 is a ribbon winding motor of the ribbon cassette 13.

As shown in FIG. 1, the head retreat mechanism 16 includes the base plate 2
1, the thermal head 12 is attached to the base plate 21, and the thermal head 12 is rotatably provided in the direction in which the thermal head 12 approaches and separates from the platen 11 with a first shaft 22 parallel to the platen 11 as a fulcrum. 2 as a first urging means for urging the mounting member 31 and the mounting member 31 in a direction in which the thermal head 12 is separated from the platen 11.
Two torsion coil springs 41A and 41B, and operating lever 6
1, a base member 21 has a base end portion rotatably supported about a second shaft 23, which is parallel to the first shaft 22 and is a fulcrum, and a tip end portion of the support member 51. It is composed of a tension coil spring 71 as second urging means for urging the support member 51 to rotate in a direction approaching the mounting member 31.

Standing pieces 24A and 24B are provided at right angles on both ends of the base plate 21. Between the standing pieces 24A and 24B on both sides,
The first shaft 22 and the second shaft 23 are supported parallel to each other and parallel to the platen 11.

The mounting member 31 includes a mounting plate 32 on which the thermal head 12 is mounted, and bending pieces 33A provided at right angles to both ends of the mounting plate 32 and having lower ends rotatably supported by the first shaft 22. 33B. The attachment plate 32 is provided with a hooking piece 34 that locks one end of the tension coil spring 71. Between the bent pieces 33A and 33B on both sides, the platen 11 and the thermal head 12 are guided by guiding the ink ribbon 14 drawn from the ribbon cassette 13 to the upper end side.
A ribbon guide roller 36 for feeding the sheet to and between and a stop shaft 37 as an engaging portion are bridged over the intermediate portion.

In the torsion coil springs 41A and 41B, the coil portion 42 is inserted through the first shaft 22, one end 43 is below the second shaft 23, and the other end 44 is the lower end of the mounting plate 32 of the mounting member 31. Are locked to each. Therefore, the mounting member 31
Is urged to rotate in a direction in which the thermal head 12 is separated from the platen 11 about the first shaft 22 as a fulcrum, that is, in the clockwise direction in FIG.

The support member 51 includes a pair of engagement pieces 53A and 53B which are provided in parallel to each other via a connecting plate 52 and whose lower ends are rotatably supported by the second shaft 23. Connecting plate 52
A hook groove 54 for locking the other end of the tension coil spring 71 is formed at the upper end of the. The engaging pieces 53A, 53B are provided with engaging holes 55 that fit into the bosses 62 of the operating lever 61 at substantially intermediate positions thereof, and the mounting member 3 is also provided.
The first locking portion 56 and the second locking portion 5 are provided on the end surface facing 1
7 and a third locking portion 58 are formed respectively.
In addition, 59 is a spacer fitted into the second shaft 23.

The first locking portion 56, as shown in FIGS. 2 and 3,
When the mounting member 31 is in the state of FIGS. 3A and 3B, that is, when the thermal head 12 is in the printing posture (printing state and printing standby state), the torsion coil is engaged with the stop shaft 37 of the mounting member 31. The spring 41A and 41B are formed in a shape that prevents the mounting member 31 from rotating. Specifically, as shown in FIGS. 3A and 3B, the base plate 21
With respect to the mounting member 31, the mounting member 31 is vertically erected, and the supporting member 51 is formed in a rectangular recessed groove that engages with the stopper shaft 37 when the supporting member 51 is inclined beyond the vertical state toward the mounting member 31 side. . The groove has faces i, j, k, and faces i, k
Is perpendicular to a plane 1 parallel to the tilt direction of the support member 51.

Similarly, as shown in FIGS. 2 and 3, the second locking portion 57 is mounted in the state where the mounting member 31 is in the state shown in FIG. 3C, that is, in the direction in which the thermal head 12 is separated from the platen 11. In the state of the ribbon cassette replacement position where the member 31 is rotated by a certain angle, the mounting member 3 is engaged with the stop shaft 37 of the mounting member 31 and is twisted by the coil springs 41A and 41B.
It is formed in a shape that prevents the rotation of 1. In detail,
As shown in FIG. 3 (C), when the mounting member 31 is inclined to the support member 51 side beyond the vertical state with respect to the base plate 21 and the support member 51 is erected substantially vertically,
It is formed in a groove shape having a surface m inclined from the surface 1 toward the mounting member 31 side and obliquely upward.

Similarly, as shown in FIGS. 2 and 3, the third locking portion 58 is mounted in the state where the mounting member 31 is in the state shown in FIG. 3D, that is, in the direction in which the thermal head 12 is separated from the platen 11. When the member 31 is rotated beyond a certain angle, it is formed into a shape that engages with the stop shaft 37 of the mounting member 31 to prevent the torsion coil springs 41A and 41B from rotating the mounting member 31. Specifically, as shown in FIG. 3D, the mounting member 31 further inclines in the same direction from the state of FIG. 3C with respect to the base plate 21, and the supporting member 51 also inclines in the same direction. In this state, the surface m is formed in a shape having a linear surface p extending from the tip end n of the surface m toward the second axis 23.

Next, the operation of this embodiment will be described with reference to FIG.

Now, in the state of FIG. 3A, that is, in the printing state in which the platen 11 presses the ticket paper 15 and the ink ribbon 14 against the thermal head 12, when the platen 11 rotates, the ticket paper 15 and the ink ribbon 14 are fed. At this time, the pressure contact force F ₁ of the platen 11 urges the mounting member 31 to rotate clockwise about the first shaft 22 as a fulcrum, so that the support member 51 moves to the second position via the stop shaft 37.
The shaft 23 is urged to rotate in the clockwise direction with the shaft 23 as the supporting point. When the support member 51 tries to rotate clockwise about the second shaft 23 as a fulcrum, the first locking portion 5 is attached to the lower edge of the stop shaft 37.
Since the surface k of 6 is in contact, the force of arrow F ₂ acts on the support member 51 in the direction perpendicular to the surface k. This is a force that urges the support member 51 to rotate counterclockwise about the second shaft 23 as a fulcrum, so that the forces in both directions are balanced.
The support member 51 is fixed in this state. Therefore,
Printing can be performed in this state.

Next, in the state of FIG. 3B, that is, in the print standby state in which the platen 11 is separated from the thermal head 12, the operation lever 61 is rotated clockwise against the tension coil spring 71. Boss 62 of operating lever 61
The support member 51 engaged with is urged to rotate clockwise with the second shaft 23 as a fulcrum. Then, the force of arrow F ₃ acts on the stop shaft 37 in the direction perpendicular to the surface k of the first locking portion 56. When the counterclockwise turning force of the mounting member 31 due to the force F ₃ becomes larger than the forces of the torsion coil springs 41A and 41B and the tension coil spring 37, the mounting member 31 moves to the first position.
The shaft 22 is rotated counterclockwise about the fulcrum. Then, the stop shaft 37 slides the surface k of the first locking portion 56 to the left. When the stop shaft 37 is disengaged from the surface k to the disengagement surface l, the mounting member 31 is rotated in the clockwise direction, so that the stop shaft 37 slides downward on the surface l and the second locking surface 57.
Is locked to the surface m. That is, it is fixed in the state of FIG. Therefore, the ribbon cassette 13 can be replaced in this state.

Here, in the state of FIG. 3 (C), the operation lever 61
If a further attempt is made to rotate clockwise against the tension coil spring 71, the stopper shaft 37 will be locked by the second locking portion 5
The force of arrow F ₄ acts in the direction perpendicular to the plane m of 7. Since the direction of this force F _{4 is} the direction connecting the axis of the first shaft 22 and the axis of the stopper shaft 37, the mounting member 31 is attached to the first shaft 22.
It cannot rotate clockwise with respect to. That is,
Only by rotating the operation lever 61, the mounting member 31 is moved to the third position.
It cannot be further rotated clockwise from the state shown in FIG. On the other hand, when the operation lever 61 is rotated counterclockwise in this state, the stopper shaft 37 slides up on the surface 1 and is locked by the first locking portion 56. Therefore, by operating only the operation lever 61, the state shown in FIG. 3B and the state shown in FIG. 3C can be switched.

Next, in the state of FIG. 3C, the attachment member 31 is slightly rotated counterclockwise and the operation lever 61, that is, the support member 51 is slightly rotated clockwise, and the stopper shaft 37 is moved to the second locking portion 57. Over the tip n of the. Then, since the mounting member 31 is rotated clockwise by the action of the torsion coil springs 41A and 41B, the stopper shaft 37 slides down the surface p of the third engaging portion 58 and stops in the state of FIG. 3 (D). To do. Therefore, in this state, since the thermal head 12 is in the upward posture, the heat generating surface of the thermal head 12 and the peripheral surface of the platen 11 can be easily cleaned. By rotating the operation lever 61 counterclockwise from this state, the state can be returned to the state shown in FIG. 3 (B).

Therefore, according to this embodiment, the mounting member 31 having the thermal head 12 and the stopper shaft 37 is rotatably provided on the base plate 21, and the support member 51 is rotatably provided on the base plate 21. The first locking portion 56 that engages with the stopper shaft 37 at the position where the head 12 is in the printing posture (printing state and printing standby state) and the mounting member 31 is rotated by a fixed angle in the direction in which the thermal head 12 is separated from the platen 11. Second engaging with the stopper shaft 37 at the moved position
And a third locking portion 58 that engages with the stopper shaft 37 at a position where the mounting member 31 further rotates beyond a certain angle and is formed. By engaging the locking portion 57, the ribbon cassette 13 can be replaced, and by engaging the stopper shaft 37 with the third locking portion 58, the thermal head 12 and the platen 11 can be cleaned.

In particular, when the stopper shaft 37 is engaged with the third locking portion 58, the thermal head 12 is in an upward state, so that the heat generating surface of the thermal head 12 and the peripheral surface of the platen 11 can be easily cleaned. Can be done.

Further, the switching between the printing posture position and the ribbon cassette 13 replacement position is performed only by the rotating operation of the operation lever 61, and the switching to the cleaning position is performed by the cooperative operation of the mounting member 31 and the operation lever 61. The operation for replacing the ribbon cassette 13 and the operation for the maintenance work can be distinguished.

Further, the operating direction of the operating lever 61 and the thermal head 12
Therefore, the operating direction of the operating lever 61 is not mistaken. Moreover, the operating lever 61
The power to operate is also light.

[Advantages of the Invention] As described above, according to the present invention, the mounting member and the support member are arranged at three engaging positions, that is, the print head is in the print posture position.
Since the mounting member and the supporting member are engaged with each other at the position where the mounting member is rotated a certain angle in the direction in which the print head is separated from the platen and the position where the mounting member is rotated beyond the certain angle, Replacement and maintenance work can be easily performed. Further, it is possible to distinguish the operation at the time of replacement of the ribbon cassette and the operation at the time of maintenance work.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
FIG. 1 is an exploded perspective view showing a head retracting mechanism, and FIG.
FIG. 3 is a view showing a third locking portion, FIG. 3 is a view showing an operating state, and FIG. 4 is a front view showing the entire structure. FIG. 5 is a view showing a conventional head retracting mechanism. 11 ... Platen, 12 ... Thermal head, 21 ...
Base plate, 22 ... first axis, 23 ... second axis, 31
...... Mounting member, 37 ...... Stop shaft (engagement part), 41
A, 41B ... torsion coil spring (first biasing means),
51 ... Support member, 56 ... First locking portion, 57 ... Second locking portion, 58 ... Third locking portion, 61 ... Operating lever, 71 ... Extension coil spring (first 2 biasing means).

Claims (1)

[Scope of utility model registration request] 1. A base plate, a print head, and an engaging portion, and the print head is rotated in a direction toward and away from the platen with a first axis parallel to the platen as a fulcrum on the base plate. A mounting member provided freely, a first biasing unit for biasing the mounting member in a direction in which the print head is separated from the platen, and an operation lever, and a base end portion of the base plate. A support member rotatably supported about a second shaft parallel to the first shaft as a fulcrum, and a support member rotatably mounted in a direction in which a tip portion of the support member approaches the mounting member. A second urging means for urging the support member, and the support member is rotated by the first urging means by engaging the engaging portion of the mounting member with the print head in the printing posture. And the operation lever is operated against the second urging means. At this time, the first engaging portion that is disengaged from the engaging portion and the engaging portion of the attaching member when the attaching member rotates a certain angle in the direction in which the print head is separated from the platen. The mounting member is prevented from rotating by the first urging means, the mounting member is rotated against the first urging means, and the operating lever is operated against the second urging means. And a second locking portion which is disengaged from the engaging portion, and an engagement of the mounting member when the mounting member rotates beyond a certain angle in a direction in which the print head is separated from the platen. A head retracting device for a printer, characterized in that a third engaging portion which engages with the joint portion and prevents rotation of the attachment member by the first urging means is formed.