JPH115320A - Line thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calmly open a cover member supporting a thermal head without making an operator feel anxiety about safety. SOLUTION: A damper 22 is set which urges by means of a coveropening spring 18 a cover member 6 supporting a thermal head 7 to separate the member by a predetermined angle from a platen 4, and applies a smaller resistance force than an urging force of the opening spring 18 from a middle stage to a final stage of the separation of the cover member 6 from the platen 4. When a stop lever 13 is detached from the cover member 6, the cover member 6 is separated together with the thermal head 7 from the platen 4 because of the urging force of the opening spring 18. However, the resistance force of the damper 22 acts to the cover member 6 from the middle stage to the final stage of the separation, whereby an open speed of the cover member 6 is attenuated. Accordingly the cover member 6 can be opened calmly without causing an operator anxiety about safety.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a line thermal printer.

[0002]

2. Description of the Related Art In a line thermal printer, printing is performed by driving a thermal head in a state where paper and an ink ribbon are pressed against a platen by a thermal head.
When the paper or the ink ribbon is set between the platen and the thermal head or when maintenance is performed, the thermal head is separated from the platen.

A typical conventional example will be described below with reference to FIG. A thermal head 53 contacting a platen 52 is held by a cover member 51 having an open lower surface via a head support 54. A head support 54 having a thermal head 53 fixed to the lower surface is supported on both side surfaces of the cover member 51 by a shaft 54a so as to be vertically rotatable. Also, the head support 5 is provided on the inner surface of the cover member 51.
A lifting screw (not shown) for lifting 4 is screwed. A hole (not shown) through which a lifting screw passes is formed on the free end side of the head support 54. This hole is sized smaller than the head of the lifting screw. That is, when the cover member 51 rotates upward, the head support 54 is lifted by the head of the lifting screw. This head support 5
A head pressing spring 55 is interposed between the upper surface of the cover 4 and the lower surface of the cover member 51.

At one end of the cover member 51, a cylindrical fulcrum shaft 57, which is rotatably supported by opposing side plates 56 (only one side is shown), is provided. Two spring members 58 formed by bending a steel wire are inserted through the fulcrum shaft 57. The two spring members 58 have a fixed leg 59 at one end and a movable leg 60 at the other end. The fixed leg 59 is engaged with a tongue piece 61 formed on the side plate 56, and the movable leg 60 is The cover member 51 is urged upward by being engaged with the tongue piece 62 fixedly provided on the side surface of the cover member 51 in a state where the stress is increased by twisting in the turning direction together with the middle portion of the cover member 58.

The side plate 56 has both ends of the shaft of the platen 52,
Both ends of a lever shaft 64 to which a pair of left and right locking levers 63 are fixedly fitted are rotatably supported. These locking levers 63 are urged in one direction by a lock spring 65, and the locking claws 6 which are engaged with pin-shaped locking protrusions 66 projecting from both sides of the free end side of the cover member 51 at the upper part.
7 are formed.

Therefore, the cover member 51 is held at a fixed position by engaging the locking claws 67 of the locking lever 63 with the locking projections 66. In this state, since the head support 54 is pressed downward by the pressure of the head pressing spring 55, the thermal head 53 presses the paper or the ink ribbon against the platen 52 (not shown). In this case, the ink ribbon is unnecessary when using the thermosensitive coloring paper. Printing is performed by driving the thermal head 53 in this state.

Here, the platen 52 and the thermal head 5
An operation of rotating the cover member 51 upward for setting a sheet or an ink ribbon between the cover member 3 and the printer or for maintenance will be described. Conventionally, the spring member 58 may or may not be provided.

When the spring member 58 is not provided, when the locking lever 63 is rotated against the urging force of the lock spring 65 to release the locking claw 67 from the locking projection 66, the cover member 51 is extended. The thermal head 53 is moved upward by the force of the head pressing spring 55, and the head support 54 is lifted by the lifting screw to separate the thermal head 53 from the platen 52.
In this case, since the deflection amount of the head pressing spring 55 is small, the separation distance of the thermal head 53 from the platen 52 is small. In order to align the platen 52 with the thermal head 53, an inverted U-shaped engaging piece (not shown) fitted to a bearing or the like on both sides of the platen 52 is formed on both sides of the head support 54. The distance between the thermal head 53 and the platen 52 is further reduced due to the frictional force between the locking piece and the bearing. Therefore, after rotating the locking lever 63 in the release direction, the cover member 51 must be manually rotated by a large angle in the opening direction.
Operation is troublesome.

When the spring member 58 is provided, the cover member 51 can be rotated in the opening direction over a large range by the urging force of the spring member 58.

[0010]

As described above, unless a biasing member such as a spring member 58 for biasing the cover member 51 upward is provided, the thermal head 53 from the platen 52 is not provided.
It is difficult to set paper and ink ribbon because the separation distance is small. However, the platen 52 and the thermal head 5
The operation of opening the cover member 51 by hand to widen the gap with the third member 3 is troublesome.

In the case of a device provided with an urging member such as a spring member 58 for urging the cover member 51 upward, it is difficult to control the urging force of the spring member 58, and if the urging force is strong, the cover member 51 rotates vigorously. I do. In particular, in order to align the platen 52 with the thermal head 53, an inverted U-shaped engaging piece fitted to a bearing or the like on both sides of the platen 52 is used as the head support 5.
When it is formed on both sides of 4, the locking piece rotates vigorously as soon as it comes off the bearing. This may surprise the operator. Further, in a printer in which the rotation range of the cover member 51 is increased in order to facilitate paper setting, a part of the cover member 51 may protrude outside the printer main body. There is a possibility that the operator may be surprised by turning vigorously.

[0012]

According to the first aspect of the present invention,
A cover member provided so as to be able to freely contact and separate from the platen about the point axis, a thermal head resiliently supported by the cover member so as to be pressed against the platen, and locked by the cover member A locking lever that locks the locking lever to the cover member to maintain the thermal head in pressure contact with the platen. A cover opening spring having a biasing force determined so as to separate from the platen is provided, and a resistance force smaller than the biasing force of the cover opening spring is applied to the cover member from a middle stage to a late stage of the separating operation of the cover member from the platen. To provide a damper.

Accordingly, when the locking lever is removed from the cover member, the cover member is separated from the platen together with the thermal head by the urging force of the cover opening spring. During the middle to late stages of the separating operation, the opening speed of the cover member is attenuated because the resistance of the damper acts on the cover member.

According to a second aspect of the present invention, in the first aspect of the present invention, the damper is displaceably supported so as to interfere with the cover member from a middle stage to a late stage of the separating operation of the cover member from the platen. And a damper spring that urges the operating body in a direction that interferes with the cover member.

Therefore, in the middle stage of the separating operation of the cover member from the platen, the operating body interferes with the cover member and is displaced while bending the damper spring. In this process, since the force of the damper spring gradually increases, the opening speed of the cover member is attenuated toward the desired opening position.

According to a third aspect of the present invention, in the first aspect of the present invention, the rotation range of the cover member is set to a range where a part of the cover member protrudes outside the printer main body from a position hidden inside the printer main body. The timing at which the resistance of the damper starts to act on the cover member is determined almost immediately before the timing at which the cover member starts to protrude outside the printer body.

Therefore, even if the cover member is vigorously rotated in the initial stage of the separating operation from the platen, the opening speed is attenuated by the damper when the cover member protrudes outside the printer body.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. Reference numeral 1 denotes a printer main body. The printer main body 1 has only one side, but has side plates 1a opposed to each other. A transport path 2 is formed, and a plurality of transport rollers 3 and a platen 4 are rotatably arranged along the sheet transport path 2. A paper discharge receiver 2c is formed below the paper discharge port 2b. Notches (not shown) are formed on the bottom and side surfaces of the paper discharge receiver 2c to allow the cover member 6 to pivot about the fulcrum shaft 5. The fulcrum shaft 5 is erected on the opposing side plates 1a.

A thermal head 7 is held by a cover member 6 having an open lower surface via a head support 8 so as to resiliently contact the platen 4. Specifically, a head support 8 having a thermal head 7 fixed to the lower surface is rotatably supported by a fulcrum shaft 5. A lifting screw 9 for lifting the head support 8 is screwed onto the inner surface of the cover member 6. A hole (not shown) through which the lifting screw 9 penetrates is formed on the free end side of the head support 8. This hole has a size smaller than the head of the lifting screw 9. That is, the head support 8 is configured to be lifted by the head of the lifting screw 9 when the cover member 6 rotates upward. Also, the upper surface of the head support 8 and the cover member 6
A head pressing spring 10 is interposed between the lower surface and the lower surface of the head. Further, a platen 4 is provided on both sides of the head support 8.
Of the shaft 4a or a bearing that supports the shaft 4a.

Next, both ends of a lever shaft 12 are rotatably supported on the opposing side plates 1a, and locking levers 13 are fixedly fitted near both ends of the lever shaft 12. These locking levers 13 connected by the lever shaft 12 are urged clockwise by a lock spring (not shown). A pin-shaped locking projection 14 locked to the locking lever 13 is provided on both sides of the free end side of the cover member 6.
Is erected.

The cover member 6 in this embodiment has a lever 15 on one side. Specifically, lever 1
The center portion 5 is rotatably supported by the fulcrum shaft 5 and the upper end is fitted to a pin 16 erected on the side surface of the cover member 6. This lever 1
At the lower end of 5, a pin 17 projecting sideways is provided upright. A cover opening spring (torsion coil spring) 18 is wound around the fulcrum shaft 5. The cover opening spring 18 has one hook 19 supported by a shaft 20 erected on the side plate 1 a and the other hook 21 abutted on the pin 16 of the cover member 6, thereby covering the fulcrum shaft 5. The member 6 is urged in a direction for separating the member 6 from the platen 4.

A damper 22 is provided to apply a resistance force to the cover member 6 that is weaker than the urging force of the cover opening spring 18 during the middle to late stages of the separating operation of the cover member 6 from the platen 4. This damper 22
Urges the operating body 24 rotatably supported by a shaft 23 erected on the side plate 1a, and the operating body 24 in a direction to interfere with the pin 17 of the lever 15 forming a part of the cover member 6. The damper spring 25 is formed by a damper spring 25 and a stopper 26 that regulates a rotation range of the operating body 24 in a direction urged by the damper spring 25. The stopper 26 regulates the stationary position of the operating body 24 so as to interfere with the pin 17 of the cover member 6 from the middle stage to the late stage of the turning operation of the cover member 6 in the direction away from the platen 4.

In such a configuration, as shown in FIG. 1, the cover member 6 is held at a fixed position by engaging the locking lever 13 with the locking projection 14. In this state, since the head support 8 is pressed downward by the pressure of the head pressing spring 10, the thermal head 7 presses the sheet S or the ink ribbon (not shown) against the platen 4. In this state, printing is performed by driving the thermal head 7.

When the locking lever 13 is rotated counterclockwise to disengage it from the locking projection 14 for setting the paper S or the ink ribbon between the platen 4 and the thermal head 7, or for maintenance. The cover member 6 rotates counterclockwise about the fulcrum shaft 5 by the urging force of the cover opening spring 18 and separates from the platen 4. In this case, the cover member 6 rotates from the position shown in FIG. 1 to the position shown in FIG. Thereby, the interval between the platen 4 and the thermal head 7 is greatly widened, and the paper S and the ink ribbon can be easily set. In addition, since it is not necessary to manually rotate the cover member 6 upward largely, the operability is also improved.

As described above, the cover member 6 rotates in the direction away from the platen 4 by the urging force of the cover opening spring 18, but in the middle of the separating operation (a part of the cover member 6 as shown in FIG. 2). Right before projecting to the upper part of the paper discharge receiver 2c outside the printer body 1).
The operating body 24 interferes with the pin 17 of the lever 15 which is a part of the lever. By setting the force of the damper spring 25 so that the resistance force applied from the operating body 24 to the pin 17 is smaller than the urging force of the cover opening spring 18 at this time, the platen 4 of the cover member 6 In the middle and late stages (corresponding to FIG. 3) of the separating operation of the lever 15, the operating body 24 is connected to the cover member 6 (specifically,
7) counterclockwise about the shaft 23 while bending the damper spring 25 while interfering with 7). In this process, the force of the damper spring 25 gradually increases. Thereby, even if the cover member 6 rotates vigorously at the moment when the locking piece 11 is disengaged from the shaft 4a of the platen 4 in the early stage of the separating operation of the cover member 6 from the platen 4, the cover member 6 can be moved to a desired position. The opening speed is attenuated by the resistance force from the operating body 24 that gradually increases toward the opening position.

Therefore, as shown in FIGS. 2 and 3, even if the cover member 6 is rotated until it protrudes out of the printer body 1, the operator is not surprised. Further, the cover member 6 can be opened quietly.

When the cover member 6 is manually rotated clockwise to press the thermal head 7 against the platen 4 from the state shown in FIG. 3, the force of the damper spring 25 can be used. The force can be reduced.

In the embodiment, the damper is not limited to the combination of the operating body that interferes with the cover member and the damper spring that urges the operating body. For example, the damper elastically bends due to the interference with the cover member. The soft member itself may be used as a damper, or a cylinder or the like in which gas is sealed may be used as a damper.

Further, in order to resiliently support the thermal head 7 on the cover member 6 so as to be pressed against the platen 4, the thermal head 7 is moved via the head support 8 urged in the direction of the platen 4 by the head pressing spring 10. Although the description has been made with the thermal head 7 attached to the cover member 6, the thermal head 7 itself may be attached to the cover member 6 via an elastic member.

[0030]

According to the first aspect of the present invention, the cover member for supporting the thermal head is urged by the cover opening spring so as to be separated from the platen by a predetermined angle, and the cover member is rotated in the direction away from the platen. In the middle to late stages, a damper was provided to apply a weaker force to the cover member than the urging force of the cover opening spring.
When the locking lever is removed from the cover member, the cover member separates from the platen together with the thermal head due to the biasing force of the cover opening spring, but during the middle and late stages of this separation operation, the resistance of the damper acts on the cover member. The opening speed of the cover member can be reduced. Thereby, the operator is not surprised and the cover member can be opened quietly.

According to a second aspect of the present invention, in the first aspect of the present invention, the damper is displaceable so as to interfere with the cover member from the middle stage to the late stage of the turning operation of the cover member in a direction away from the platen. A supported working body,
Since the operating member is formed by a damper spring that urges the operating member in the direction of interfering with the cover member, in the middle stage of the separating operation of the cover member from the platen, the operating member interferes with the cover member and deflects the damper spring. Displace. In this process, since the force of the damper spring gradually increases, the opening speed can be reduced as the cover member is rotated toward a desired opening position.

According to a third aspect of the present invention, in the first aspect of the present invention, the rotation range of the cover member is set to a range where a part of the cover member protrudes outside the printer main body from a position hidden inside the printer main body. Since the time when the resistance of the damper starts to act on the cover member is determined almost immediately before the time when the cover member starts to protrude to the outside of the printer main body, in the initial stage of the separating operation of the cover member from the platen. Even if it vibrates vigorously, the opening speed can be attenuated by the damper when it protrudes out of the printer body, so that the operator is not surprised by the rotation of the cover member.

[Brief description of the drawings]

FIG. 1 is a side view showing a state in which a thermal head is in contact with a platen in one embodiment of the present invention.

FIG. 2 is a side view showing a process of a separating operation of a cover member from a platen.

FIG. 3 is a side view showing an end of a separating operation of a cover member from a platen.

FIG. 4 is an exploded perspective view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 4 platen 5 fulcrum 6 cover member 7 thermal head 13 locking lever 18 cover opening spring 22 damper 24 operating body 25 damper spring

Claims (3)

[Claims] A cover member provided so as to be able to contact and separate from a platen about a fulcrum shaft; a thermal head resiliently supported by the cover member so as to be pressed against the platen; and the cover. A locking lever locked to a member, wherein the cover member locks the locking lever to maintain the thermal head pressed against the platen; Is provided with a biasing force for releasing the cover member from the platen by a predetermined angle, and a resistance force weaker than the biasing force of the cover releasing spring is provided from a middle stage to a late stage of the separating operation of the cover member from the platen. A line thermal printer comprising a damper provided to the cover member. 2. An operating body supported so as to be displaceable so as to interfere with the cover member from a middle stage to a late stage of a separating operation of the cover member from the platen, and a direction in which the operating body interferes with the cover member. 2. A line thermal printer according to claim 1, wherein said line thermal printer is formed by a damper spring biasing said liner. 3. The rotation range of the cover member is defined as a range in which a part of the cover member protrudes outside the printer main body from a position hidden inside the printer main body, and when the resistance of the damper starts to act on the cover member. 2. The line thermal printer according to claim 1, wherein the distance is set substantially immediately before the time when the cover member starts to protrude outside the printer body.