JP2002144611A - Line thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a line thermal printer having a mechanism for positioning a platen and a line thermal head accurately. SOLUTION: The line thermal printer comprises body frames (10, 40) having a line thermal head (43), a lock member (60) and a resilient member (44), and a cover frame (20) having a platen (22) wherein the line thermal head is movable between a print position proximate to the platen and a nonprint position retracted from the print position, the cover frame is movable between a fixing position where the platen is brought close to the line thermal head and a nonfixing position where the platen is retracted from the line thermal head, and the lock member is movable between a lock position where the cover plate is held at the fixing position and an unlock position. The resilient member urges the line thermal head toward the print position side and urges the lock member toward the lock position side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line thermal printer having a platen and a line thermal head.

[0002]

2. Description of the Related Art Conventionally, in a line thermal printer which performs printing by bringing a platen and a line thermal head close to each other, it is necessary to appropriately bring the platen and the line thermal head close in order to perform printing with high accuracy. In addition, the platen and the line thermal head have been separated from each other for replenishment of paper, jam clearance, and the like.

For this reason, when printing is performed, a mechanism for holding the platen and the line thermal head in an appropriate positional relationship, a mechanism for separating the platen and the line thermal head from each other, and the like are required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a line thermal printer having a mechanism for accurately positioning a platen and a line thermal head.

[0005]

According to another aspect of the present invention, there is provided a printer including a line thermal head, a main body frame having a lock member and an elastic member, and a cover frame having a platen. The head is configured to be movable between a printing position close to the platen and a non-printing position retracted from the printing position, and the cover frame is a mounting position where the platen approaches the line thermal head and a non-mounting position where the platen is retracted from the line thermal head. The lock member is configured to be movable between a lock position for holding the cover frame at the mounting position and a release position for releasing the hold, and the elastic member biases the line thermal head toward the printing position. And biasing the lock member to the lock position side. The biasing of the lock member for holding the cover frame and the biasing of the line thermal head toward the platen are performed by one elastic member.

Preferably, the lock member moves between the lock position and the release position in conjunction with the movement of the line thermal head between the print position and the non-print position. Further, it is preferable that the lock member has a bearing for rotatably supporting the line thermal head.

Further, the lock member preferably has a holding portion for holding the cover frame at the mounting position. Further, the cover frame has a pressing member, and when the locking member is located at the locking position, the pressing member presses the locking member toward the release position so that the cover frame can be moved to the mounting position. Is preferred.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printer according to the present invention will be described below. FIG. 1 is a schematic center sectional view of a printer according to the present invention. Here, 1 is a heat-sensitive roll, and 2 is a shaft of the heat-sensitive roll 1. Reference numeral 3 (indicated by a two-dot chain line) indicates a state in which the diameter of the roll is reduced by using the thermal paper P. Reference numeral 10 denotes a base, reference numeral 20 denotes a platen cover, and reference numeral 30 denotes a cutter unit.

The base 10 is provided with a first holding member 11, a bearing member 13, a guide member 14, and a plate holding member 15. The first holding member 11 holds the cover frame 20 rotatably about the shaft 12. Also,
The bearing member 13 rotatably holds the shaft 2 of the heat-sensitive roll 1. The guide member 14 has a function of always transporting the thermal paper P unwound from the thermal roll 1 at a substantially constant height in the direction of a later-described line thermal head 43.
When the diameter of the heat-sensitive roll 1 decreases, the position where the heat-sensitive paper P is fed out changes. Therefore, the guide member 14
Functions so that the transport direction of the thermal paper P is bent so that the thermal paper P is always transported from the same height in the direction of the line thermal head 43. Therefore, the height of the guide member 14 is
It is preferable to have a height higher than the position of the lowest point of the central axis 2 of the thermal roll paper 1.

The cover frame 20 has a regulating member 21, a platen roller 22, a platen roller shaft 23, a first engaging member 24, a fixed blade 25, a dome-shaped plate member 26, and the like. The cutter unit 30 has a movable blade 31, a second engagement member 32, a swing support member 33, a projection 34, a stopper 35, and the like.

The plate 40 is fixed on the plate holding member 15, and a guide plate 41 and a sensor 4
2, line thermal head 43, elastic member 44 and second
A holding member 45 and the like are provided. Further, the second holding member 45 is provided with a groove 46 and a third engagement member 47. Therefore, the swing support member 33 of the cutter unit 30
Is inserted into the groove 46 provided in the second holding member 45, and the cutter unit 30 is
It is held by a holding member 45 so as to be able to swing up and down with 3 as a fulcrum.

The sensor 42 is mounted below the guide plate 41 to detect the presence or absence of the thermal paper P. Further, as the sensor 42, a reflection type sensor including a light emitting element and a light receiving element is used. If the thermal paper P is not detected at the position of the sensor 42, the sensor 42 sends a no-paper signal to a control circuit (not shown). In the reflection type sensor, the presence or absence of a sheet is detected by emitting light from a light emitting element toward a transport path and causing light reflected from the sheet to enter a light receiving element. Therefore, in particular, it is preferable that the distance between the sensor and the paper is substantially constant in the reflection type sensor. In this embodiment, a reflection type sensor is used, but another type of sensor may be used.

Reference numeral 50 denotes a projection 34 of the cutter unit 30.
An elastic member (helical spring) provided between the second holding member 45 and the second holding member 45, and constantly applies a biasing force to rotate the cutter unit 30 clockwise in FIG. 1 to the cutter unit 30. . Hereafter, the base 10
The plate 40 and the various members provided on the base 10 and the plate 40 are collectively referred to as a main body frame. In FIG. 1, the platen roller shaft 23 is held on the main body frame by a lock member 60 described later,
Thereby, the cover frame 20 is maintained in the state shown in FIG. 1, and this state is referred to as the cover frame 20 being at the printing position. Further, a state in which the holding of the platen roller shaft 23 is released, for example, a state in FIG. 2 is referred to as a state where the cover frame is at the retracted position.

When the cover frame 20 is held in the state shown in FIG. 1, the first engaging member 24 of the cover frame 20 is engaged with the second Is pressed counterclockwise, and the cutter unit 30 is held at the position shown in FIG. 1 while opposing the urging force of the elastic member 50. Further, at this time, the protrusions 3 on both sides of the movable blade 31 of the cutter unit 30 are provided.
1a and 31b are fixed blades 25 on the cover frame 20 side.
Is pressed from top to bottom in the figure, whereby the fixed blade 25
The movable blade 31 is positioned so that both side protruding portions 31a and 31b of the movable blade 31 are in contact with the movable blade 31. From the state of FIG.
The movable blade 31 is configured to slide on the fixed blade 25 toward the cover frame 20 by a drive mechanism (not shown) so that the thermal paper P can be cut.

The elastic member 44 includes a line thermal head 43.
Are biased toward the platen roller 23, and the thermal paper P is sandwiched between the platen roller 23 and the line thermal head 43. When the platen roller 23 rotates in the state of FIG. 1, the thermal paper P is fed out of the thermal roll 1, and is transported upward in the drawing.

In the line thermal head 43, a plurality of heating elements are provided in a row in the longitudinal direction of the platen roller 23, and the heating elements generate heat by a drive circuit (not shown), thereby printing on the thermal paper P. And so on. Therefore, as the platen roller 22 rotates, printing is performed on the thermal paper P while the thermal paper P is being conveyed, and the thermal paper P is discharged outside the printer. In the present embodiment, the platen is formed in a roller shape. However, if the platen has a shape that can regulate the positional relationship between the print head and the sheet,
It is also possible to use other shapes without being limited to the roller shape. Further, when a roller-shaped platen is not used, a transport mechanism for transporting the paper separately is required.

FIG. 2 shows a case where the cover frame 20 is at the retracted position. FIG. 2 shows the state of the platen roller shaft 23.
Has been released. In the state of FIG. 2, the first engaging member 24 of the cover frame 20 is engaged with the second engaging member of the cutter unit 30 and does not press the cutter unit 30. As a result, an urging force is applied so as to rotate in the clockwise direction in FIG. However, when the stopper 35 of the cutter unit 30 is engaged with the third engagement member 47 provided on the frame 40, the stopper 35 is configured not to rotate clockwise beyond the position shown in FIG. In FIG. 2, the line thermal head 43 is held at a position retracted from the platen roller 23 side against the urging force of the elastic member 44 by a lock member 60 (not shown).

FIG. 3 is a top view of the state of FIG. 1 as viewed from above in FIG. In FIG. 3, reference numerals 24 a and 24 b are projecting portions on both sides of the first engagement member 24 provided on the cover frame 20. Reference numeral 27 denotes a gear provided on the platen roller shaft 23. Further, 48 is the plate 40
This is the gear provided above. The gear 48 receives a driving force from a motor (not shown), engages with the gear 27, and rotates the shaft of the platen roller 23. Further, reference numeral 60 denotes a lock member for holding the cover frame 20 at the position shown in FIG. In addition, as can be understood from FIG. 3, the thermal paper P passes between the cover frame 20 and the cutter unit 30 and between both side protruding portions 24 a and 24 b of the first engagement member 24.

FIG. 4 is a top view of the state of FIG. 2 as viewed from above in FIG. In FIG. 4, 31a and 31b are projecting portions on both sides of the movable blade 31. 32a and 32b
Indicates the distal end portions on both sides of the second engagement member. FIG. 4 shows a state in which the stopper 35 of the cutter unit 30 and the third engagement member 47 provided on the plate 40 are engaged.

FIG. 5 is a diagram showing a tip portion of the cover frame 20. Reference numeral 28 denotes an opening provided in the regulating member 21. The opening 28 is provided exactly corresponding to the position where the sensor 42 is provided. 203 and 2
Reference numeral 05 denotes a bearing portion that rotatably supports the platen roller shaft 23. 201 and 204 are sheet metal frame pairs provided with bearing portions 203 and 205. 20
Reference numeral 2 denotes a pressing portion provided on the sheet metal frame 201.

The regulating member 21 is arranged upstream of the platen roller 22 in the direction of transport of the thermal paper P, and has a width capable of regulating the thermal paper P over substantially the entire width of the thermal paper P. In addition, the distance between the thermal paper P and the sensor 42 is maintained substantially constant, thereby preventing the sensor 42 from malfunctioning in detection.
The regulating member has a substantially flat portion, and the flat portion is disposed so as to face the sensor 42. Further, the opening 28 is provided with the cover frame 20 of FIG.
Is provided almost directly above the sensor 42 in a state where is located at the printing position. Light from the light emitting element of the sensor 42 is reflected on the regulating plate 21, and despite the absence of the thermal paper P, the thermal paper P Prevents misunderstanding that there is. In this embodiment, the regulating member is provided over substantially the entire width of the thermal paper P.
It is not necessary to provide a regulating member over the entire width of the thermal paper P as long as the distance between the thermal paper P and the sensor 42 can be maintained substantially constant.

As described above, the thermal paper P is applied to the thermal roller 1
And is slightly bent in the transport direction by the guide member 14, and then transported while being in contact with a substantially flat portion of the lower end of the regulating member 21 of the cover frame 20, and nipped by the platen roller 22 and the line thermal head 43. While being discharged upward in FIG.

Hereinafter, the mutual relationship among the line thermal head 43, the elastic member 44, and the lock member 60 will be described in detail. FIG. 10 shows the line thermal head 43 and the elastic member 4.
4 is a perspective view showing the relationship between the lock member 4 and the lock member 60. FIG. FIG.
At 0, 401 and 411 are side walls, which are fixed to the plate 40. An elastic member 44 composed of a spring or the like urges the line thermal head 43 toward the platen roller 22.

At the end of the line thermal head 43 on the near side in the figure, a square pillar-shaped shaft 73 is provided.
Is fitted in a columnar spacer 70. Also,
The columnar spacer 70 is provided with protrusions 71 and 72. Further, the spacer 70 is configured to be inserted into the bearing e of the lock member 60 through the opening 405 of the side wall 401. The other end of the line thermal head 43 is also provided with a square pillar-shaped shaft, and the shaft is fitted in the claw member 80.

FIG. 11 shows the shape of the lock member 60.
FIG. 11A shows the surface of the lock member 60, and FIG.
(B) shows the back surface of the lock member 60. a is the first
, B is a claw portion, c is a second cam portion, d is a handle portion, e is a bearing portion, f is a third cam portion, and g is a fourth cam portion. The projection e of the spacer 70 is provided on the bearing portion e.
And 72 are provided so as to prevent the spacer 70 once inserted into the lock member 60 from easily coming off. The spacer 70 is rotatably inserted into the bearing portion e.

FIG. 6 shows the position of the lock member 60 when the cover frame 20 is at the mounting position shown in FIGS. 1 and 3. As shown in FIG. 10, since the line thermal head 43 is urged toward the platen roller 22 by the elastic member 44, the lock member 60 is interposed via the shaft 73 of the line thermal head and the spacer 70.
6, a force in the direction of arrow A is acting. As a result, the claw portion b of the lock member 60 presses the platen roller shaft 23 against the U-shaped groove 402 of the side wall 401 and holds the platen roller shaft 23 so that the platen roller shaft 23 does not come off easily. By holding the platen roller shaft 23, the cover frame 20 is held at the mounting position. In FIG. 6, the third cam portion f of the lock member 60 is engaged with the projection 403 fixed to the side wall 401 so that the lock member 60 is not further rotated in the direction of arrow A. . The state in which the lock member 60 presses the platen roller shaft 23 against the U-shaped groove 402 in this manner is referred to as the lock member 60 being at the lock position. Further, the state where the lock member does not press the platen roller shaft 23 against the U-shaped groove is referred to as the lock member 60 being at the release position.

A case where the holding of the platen roller shaft 23 by the lock member 60 is released will be described with reference to FIGS. When the holding by the lock member 60 is released, the handle d of the lock member is rotated in the direction of arrow B in FIG. 7 while opposing the urging force of the elastic member 44. When the lock member 60 is rotated in the direction of arrow B, the engagement between the third cam portion f of the lock member 60 and the projection 403 is released, and the fourth cam portion g attempts to ride over the projection 403 (FIG. 7). When the lock member 60 is further rotated in the direction of arrow B, the fourth cam portion g completely rides over the projection 403, and the second cam portion c
4, so that the lock member 60 does not rotate in the direction of arrow B beyond that (see FIG. 8). Note that once the fourth cam portion g has completely passed over the protrusion 403, the lock member 60 is held in this state because the fourth cam portion g does not easily rotate in the opposite direction.

When the lock member 60 is moved from the position shown in FIG. 6 to the position shown in FIG.
The spacer 70 inserted in the bearing portion e of the opening 0
05 in the direction of arrow B, the line thermal head 43 also moves against the urging force of the elastic member 44,
It is moved in a direction to retreat from the platen roller 22. When the lock member 60 is in the state shown in FIG. 8, the line thermal head 43 is held in a state retracted from the platen roller 23 as shown in FIG. This state,
It is said that the line thermal head 43 is at the non-printing position.
Conversely, a state in which the line thermal head 43 is urged toward the platen roller 23 by the elastic member 44 is referred to as being at the printing position.

When the claw portion b of the lock member 60 releases the holding of the platen roller shaft 23, the cover frame 2
A value of 0 enables free movement from the mounting position to the non-mounting position. Next, the platen roller shaft 23 is
The case where the lock member 60 is held at the lock position without being held at 02 will be described with reference to FIG.

In FIG. 9, when the cover frame 20 is rotated in the direction of arrow C, the pressing member 202 of the cover frame 20 presses the first cam portion a of the lock member 60, and the cover frame 20 is further moved in the direction of arrow C. When rotated in the direction, the lock member 60 rotates so as to escape in the direction of arrow D, the claw portion b is opened, and the platen roller shaft 23 can move to the U-shaped groove 402. When the pressing member 202 of the cover frame 20 comes out below the locking member 60, the pressing member 202 does not press the first cam portion a of the locking member 60, so that the locking member 60 moves in the direction opposite to the arrow D. Rotate to return, and the claw portion b is
Is held in the U-shaped groove 402. The lock member 60 is
The pressing member 202 of the cover frame 20 causes the arrow D
, But at that time, the locking member 6
Since the fourth fourth cam portion g does not climb over the protrusion 403, it is not held at the position shown in FIG.

In this embodiment, the case where the thermal paper P is used as the paper has been described as an example. However, paper other than the thermal paper can be used. For example, it is possible to use plain paper and use an ink jet head instead of a line thermal head.

[0032]

According to the present invention, it is possible to provide a line thermal printer having a mechanism for accurately positioning a platen and a line thermal head. Further, it is possible to simultaneously urge the line thermal head to the platen and hold the cover frame to the main body frame by using one elastic member.

[Brief description of the drawings]

FIG. 1 is a schematic center sectional view of a printer according to the present invention when a cover frame is at a mounting position.

FIG. 2 is a schematic center sectional view of the printer according to the present invention when a cover frame is at a non-mounting position.

FIG. 3 is a schematic top view when a cover frame is at a mounting position in the printer according to the present invention.

FIG. 4 is a schematic top view when the cover frame is at a non-mounting position in the printer according to the present invention.

FIG. 5 is a view showing a front end portion of a cover frame in the printer according to the present invention.

FIG. 6 is a diagram showing a lock member and the like when the cover frame is at a mounting position in the printer according to the present invention.

FIG. 7 is a diagram showing a lock member and the like in the process of changing the cover frame from the state shown in FIG. 6 to the state shown in FIG. 8 in the printer according to the present invention.

FIG. 8 is a diagram illustrating a lock member and the like when the cover frame is at a non-mounting position in the printer according to the present invention.

FIG. 9 is a diagram showing a lock member and the like when the cover frame is at a non-mounting position in the printer according to the present invention.

FIG. 10 is a perspective view showing a positional relationship between a line thermal head, an elastic member, a lock member, and the like.

FIG. 11 is a view showing a lock member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermal roll 10 ... Base 11 ... 1st holding member 13 ... Bearing member 14 ... Guide member 20 ... Cover frame 21 ... Restriction member 22 ... Platen roller 23 ... Platen roller shaft 24 ... 1st engagement member 25 ... Fixed blade 28 ... Opening 30 ... Cutter unit 31 ... Movable blade 32 ... Second combined member 33 ... Swinging support member 35 ... Stopper 40 ... Plate 42 ... Sensor 43 ... Line thermal head 44 ... Elastic member 45 ... Second holding member 47 ... Third engaging member 50... Elastic member 60. Lock member 70. Spacer 73... Support shaft 202 of line thermal head 202... Pressing member 402... U-shaped grooves 403 and 404. ... claw part of the lock member c ... second cam part of the lock member d ... handle part of the lock member e ... bearing part of the lock member f ... lock Fourth cam portion of the third cam portion g ... lock member timber

Claims (5)

[Claims] 1. A line thermal printer having a main body frame having a line thermal head, a lock member and an elastic member, and a cover frame having a platen, wherein the line thermal head has a printing position close to the platen; The cover frame is configured to be movable between a non-printing position retracted from the printing position, the cover frame includes a mounting position for bringing the platen close to the line thermal head, and a non-mounting position for retracting the platen from the line thermal head. The lock member is configured to be movable between a lock position for holding the cover frame at the mounting position and a release position for releasing the hold, and the elastic member is configured to move the line thermal head. To the printing position side, and locks the lock member to the lock position. Line thermal printer, characterized in that biases the 置側. 2. The lock member moves between the lock position and the release position in conjunction with movement of the line thermal head between the print position and the non-print position. The line thermal printer according to claim 1, wherein: 3. The line thermal printer according to claim 1, wherein the lock member has a bearing portion that rotatably supports the line thermal head. 4. The line thermal printer according to claim 1, wherein the lock member has a holding portion that holds the cover frame at the mounting position. 5. The cover frame has a pressing member,
When the lock member is located at the lock position, the cover member can be moved to the mounting position by the pressing member pressing the lock member toward the release position. The printer according to claim 1.