JPH10278378A - Thermal line printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a thermal line printer main body light in weight and compact, by using a nearly V-shaped leaf spring as a leaf spring for pressing a thermal head into touch with a platen roller via a paper, and utilizing an elastic force of the leaf spring as a pressing force to the thermal head and platen roller. SOLUTION: A schematically V-shaped leaf spring 7 represents a form indicated by a chain line in an initial state. While the leaf spring 7 is elastically deformed from the state, the leaf spring 7 is inserted so that two faces defining the schematic V of the leaf spring 7 are slid in contact with engaging parts 1a, 1b provided in a main body chassis 1 and a surface of a head-supporting member 6. At the time of the insertion, an opening part 7b is engaged with an engaging part 1c and moreover, an upper end part 7a of the leaf spring 7 bent in L passes the engaging parts 1a, 1b of the main body chassis 1 and is engaged with the engaging parts 1a, 1b because of a return spring force of the leaf spring 7. Accordingly, the head-supporting member 6 is in press- contact with a platen roller 2 by a spring force of the leaf spring 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal line printer used as an output terminal such as a handy terminal or a measuring instrument.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing the structure of a conventional thermal line printer, FIG. 5 is a cross-sectional view for explaining the procedure for assembling and removing the plate spring, and FIG. It is sectional drawing which shows the direction of.

In FIG. 4, reference numeral 101 denotes a main body chassis of a thermal line printer, 102 denotes a cylindrical platen roller rotatably mounted on the main body chassis 101,
Reference numeral 103 denotes a motor serving as a drive source for rotating and driving the platen roller 102, and 104a to 104d
2, a gear train for transmitting the driving force of the motor 103; 105, a thermal head; 105a, a heating element array provided on the thermal head 105;
And the shaft 10 attached to the main body chassis 101
8, a head support member rotatably attached to 8,
Is a substantially V-shaped leaf spring that presses the heating element array 105a against the platen roller 102 via the recording paper 109, and the leaf spring 107 is provided with a locking portion 10 provided on the main body chassis 101.
1a and locking portion 106 provided on head support member 106
upper ends 107a, 107 bent into an L-shape to be locked to a
7b is provided to prevent lifting. Further, openings 107c and 107d are provided at the upper ends 107a and 107b, into which tips such as radio pliers can be fitted.

The procedure of assembling and removing the leaf spring of the conventional thermal line printer having the above-described configuration will be described with reference to FIG.

In FIG. 5A, a leaf spring 107 indicated by a dotted line shows an initial shape. In this state, the two surfaces forming the substantially V-shape of the leaf spring 107 are elastically deformed like the leaf spring 107 shown by the solid line, and the two portions forming the V-shape are provided with the locking portion 101a provided on the main body chassis 101 and the head support. It is inserted so as to make sliding contact with the locking portion 106a provided on the member 106.

When the insertion is further continued, as shown in FIG. 5B, the upper end 10 of the leaf spring 107 bent into an L shape is formed.
7 a and 107 b pass between the locking portion 101 a provided on the main body chassis 101 and the locking portion 106 a provided on the head support member 106. At this time, since the maximum elastic deformation is given to the leaf spring 107 and a spring force for returning to the initial state is applied, the state immediately changes to the state shown in FIG.

[0007] Even in this state, since the leaf spring 107 is elastically deformed, the leaf spring 107 is about to return to the initial state, and applies a spring force to the main body chassis 101 and the head support member 106. The leaf spring 107 receives a reaction force from the main body chassis 101 and the head support member 106 and tends to come off in the inserted direction. However, the locking portion 101a provided on the main body chassis 101 and the head support member 1
06, the locking portion 106a is provided.
The load applied to 06a is supported by the shaft 108 and becomes fixed.

Next, a procedure for removing the leaf spring 107 will be described with reference to FIG. When removing the leaf spring 107, first, the upper end 1 of the leaf spring 107 bent into an L-shape
Openings 107c, 107 provided in 07a, 107b
d is sandwiched between pliers or the like, and elastically deformed until the state shown in FIG. When the leaf spring 107 is moved in the reverse insertion direction in this state, the removal is completed.

Next, the direction of the force in the head pressure contact state will be described with reference to FIG. In FIG. 6, since the leaf spring 107 is elastically deformed, the leaf spring 107 generates a force F to return to the initial state, and the head support member 106
To the platen roller 102 via the thermal head 105
Force Fcosθ for pressing against the head and the head supporting member 10
6 with the platen roller 102
And a component force Fsinθ that presses in a tangential direction at a pressure contact portion with the heating element row 105a.

In order to secure a pressing force F ₀ for pressing the thermal head 105 against the platen roller 102 necessary for obtaining a reliable print quality, it is necessary to set F ₀ <Fc for a predetermined θ.
What is necessary is just to determine F so that it may become os (theta).

[0011]

However, in the thermal line printer having the above-mentioned conventional configuration, the component of the elastic force generated by the leaf spring is used to press the head support member against the platen roller via the thermal head. Although it works as a force, it is possible to obtain reliable printing.However, a force provided on the head support member as a component force for pressing the head support member holding the thermal head in a tangential direction at a pressure contact portion of the platen roller with the heating element row is provided. Also works at the stop.

Since the component force acting on the locking portion is applied to the shaft fixed to the main body chassis, it is necessary to increase the shaft diameter more than necessary to increase the rigidity of the shaft. However, there has been a problem that the weight reduction and size reduction, which are strong demands, have been largely alienated, and a problem that a dedicated tool such as radio pliers must be prepared when removing a leaf spring for head cleaning.

The present invention solves such a conventional problem,
By realizing a structure in which the elastic force of the leaf spring can be efficiently used as the pressure contact force between the thermal head and the platen roller, the thermal line printer is reduced in weight and size, and the head cleaning requires no special tools for cleaning. It is an object of the present invention to provide a thermal line printer that matches a market requirement where a spring can be attached and detached.

[0014]

To solve this problem, a thermal line printer according to the present invention comprises a platen roller rotatably supported by a body chassis of the thermal line printer, and a driving means for rotating the platen roller. A line-type thermal head, a head support member to which the line-type thermal head is attached, a shaft fixed to the main body chassis that supports the head support member, and the line-type thermal head via a recording paper. A substantially V-shaped leaf spring pressed against the platen roller, and the other end of the leaf spring opposite to one end pressing the head support member is fixed to the main body chassis or a member fixed to the main body chassis. And a means for performing the operation.

According to the structure of the present invention, the structure is such that the elastic force of the leaf spring can be efficiently used as the pressure contact force between the thermal head and the platen roller, and the weight and size of the thermal line printer can be reduced.

Further, as means for fixing the other end of the leaf spring opposite to the one end pressing the head support member to the main body chassis or a member fixed to the main body chassis, the main body chassis or the main body chassis may be fixed. A member fixed to the plate spring is provided with a locking portion for locking with the upper end of the leaf spring and an engaging portion for engaging with the opening of the leaf spring, so that it is also dedicated for head cleaning. The leaf spring can be attached and detached without tools.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a platen roller rotatably supported by a main body chassis of a thermal line printer, a driving means for rotating the platen roller, and a line type thermal head. A head support member to which the line type thermal head is attached, a shaft fixed to the main body chassis supporting the head support member, and pressing the line type thermal head against the platen roller via recording paper. And a means for fixing the other end of the leaf spring opposite to the one end pressing the head support member to the main body chassis or a member fixed to the main body chassis. With this configuration, the elastic force of the leaf spring can be efficiently used as the pressure contact force between the thermal head and the platen roller. Has an effect of weight reduction and miniaturization can be realized in the printer body.

The invention according to claim 2 of the present invention is characterized in that the main body chassis or a member fixed to the main body chassis is provided with a locking portion for locking with an upper end portion of the leaf spring, and an opening of the leaf spring. 2. The thermal line printer according to claim 1, wherein said thermal line printer has a configuration in which said plate spring is detachable without a dedicated tool even during head cleaning.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 is a perspective view showing the overall configuration of a thermal line printer according to a first embodiment of the present invention, and FIG. 2 explains the procedure for assembling and removing a leaf spring in the embodiment. FIG. 3 is a cross-sectional view showing the direction of the force when the thermal head is in a pressure contact state in the embodiment.

In FIG. 1, 1 is a main body chassis of a thermal line printer, 2 is a cylindrical platen roller rotatably mounted on the main body chassis 1, 3 is a motor serving as a driving source for driving the platen roller 2 to rotate, 4a ~ 4d
Is a gear train for transmitting the driving force of the motor 3 to the platen roller 2, 5 is a thermal head, 5 a is a heating element array provided on the thermal head 5, 6 holds the thermal head 5,
A head support member rotatably attached to a shaft 8 attached to the main body chassis 1, a substantially V-shaped leaf spring 7 for pressing the heating element array 5 a against the platen roller 2 via the recording paper 9, The spring 7 has an upper end 7a bent into an L-shape for locking with the locking portions 1a and 1b provided on the main body chassis 1, and an opening 7b for engaging with the engaging portion 1c provided on the main body chassis 1. Is provided. Further, 1d is an upper end portion 7a of the leaf spring 7 in which a human finger provided on the main body chassis 1 is inserted.
Is pressed to release the locking between the locking portions 1a and 1b and the upper end portion 7a.

FIG. 2 shows a procedure for assembling and removing the leaf spring 7 of the thermal line printer constructed as described above.
This will be described with reference to FIG.

In FIG. 2A, the leaf spring 7 indicated by a dotted line shows an initial shape. In this state, two surfaces forming a substantially V-shape of the plate spring 7 are elastically deformed like the plate spring 7 indicated by a solid line, and the two locking portions 1a and 1b provided on the main body chassis 1 It is inserted so as to make sliding contact with the surface of the head support member 6. When the insertion is further continued, as shown in FIG. 2B, the opening 7b engages with the engaging portion 1c, and at the same time, the upper end 7a of the leaf spring 7 bent into an L shape is attached to the main body chassis 1. It passes through the provided locking portion 1a. At this time, since the leaf spring 7 is subjected to the maximum elastic deformation and the spring force for returning to the initial state is applied, the state shown in FIG.

Even in this state, since the leaf spring 7 is elastically deformed, the leaf spring 7 is about to return to the initial state, and applies a spring force to the main body chassis 1 and the head support member 6. That is, the leaf spring 7 is fixed to support the reaction force from the head support member 6 by the locking portions 1 a and 1 b and the engaging portion 1 c provided on the main body chassis 1.

Next, the procedure for removing the leaf spring 7 will be described with reference to FIG. When removing the leaf spring 7, a finger is applied to the upper end 7 a of the leaf spring 7 located at the notch 1 d portion provided in the main body chassis 1, and
a and 1b in the direction of releasing the lock, and FIG.
Is moved, that is, until the leaf spring 7 is subjected to the maximum elastic deformation.

In this state, the leaf spring 7 tends to move in the reverse insertion direction due to the reaction force from the head support member 6. In this state, the locking portions 1a and 1b for restricting the movement of the leaf spring 7 in the reverse insertion direction are in a state where no effect is exhibited, and the removal of the leaf spring 7 can be easily realized. That is, there is an effect that the detachment can be easily performed only by a human hand without using a special tool.

Next, the direction of the force in the head compression state will be described with reference to FIG. In FIG. 3, since the leaf spring 7 is elastically deformed, a force F for returning the leaf spring 7 to the initial state is generated, and the head supporting member 6 is pressed against the platen roller 2 via the thermal head 5. It is the power to do. The reaction force that the leaf spring 7 receives from the head support member 6 is such that the other end opposite to the one end pressing the head support member 6 has the engaging portions 1a and 1b provided on the main body chassis 1 and the engaging portion 1c.
, And the leaf spring 7 is maintained in a fixed state.

That is, F = F ₀ with respect to the pressing force F ₀ for pressing the thermal head 5 against the platen roller 2 necessary for obtaining reliable print quality, and the elastic force generated by the leaf spring 7 is efficiently increased. Everything can be used as the originally required pressing force. For this reason, an unnecessary force is not applied to the shaft 8 fixed to the main body chassis 1 that supports the head support member 6, so that the shaft diameter can be minimized, and the weight of the thermal line printer can be reduced. The effect that size reduction can be achieved is obtained.

[0028]

As described above, the thermal line printer according to the present invention solves the conventional problem that the shaft diameter for supporting the head supporting member must be increased, and efficiently increases the elastic force of the leaf spring. By using everything as the head pressure, the thermal line printer can be easily reduced in weight.
In addition to the advantageous effect that the size can be reduced, the leaf spring can be easily removed without a special tool when removing the leaf spring for cleaning the thermal head.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of a thermal line printer according to an embodiment of the present invention.

FIG. 2 is a sectional view for explaining a procedure of assembling and removing the leaf spring according to the embodiment.

FIG. 3 is a cross-sectional view showing the direction of the force of the thermal head according to the embodiment in a pressed state.

FIG. 4 is a perspective view showing the overall configuration of a conventional thermal line printer.

FIG. 5 is a sectional view for explaining a procedure of assembling and removing the leaf spring.

FIG. 6 is a cross-sectional view showing a direction of a force of the thermal head in a pressure contact state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body chassis 1a Locking part 1b Locking part 1c Engaging part 1d Notch 2 Platen roller 3 Motor 4a Gear train 4b Gear train 4c Gear train 4d Gear train 5 Thermal head 5a Heating element train 6 Head support member 7 Plate spring 7a Upper end 7b Opening 8 Axis 9 Recording paper 101 Main body chassis 101a Locking portion 102 Platen roller 103 Motor 104a Gear train 104b Gear train 104c Gear train 104d Gear train 105 Thermal head 105a Heating element train 106 Head support member 106a Locking portion 107 Leaf spring 107a Upper end 107b Upper end 107c Opening 107d Opening 108 Shaft 109 Recording paper

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shozo Gray Hair 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial

Claims (2)

[Claims] 1. A platen roller rotatably supported by a main body chassis of a thermal line printer, driving means for rotating the platen roller, a line-type thermal head, and a head support member to which the line-type thermal head is attached. A shaft fixed to the main body chassis that supports the head support member, a substantially V-shaped leaf spring that presses the line type thermal head against the platen roller via recording paper, A means for fixing the other end opposite to the one end pressing the head support member to the main body chassis or a member fixed to the main body chassis. 2. The main body chassis or a member fixed to the main body chassis is provided with a locking portion for locking with an upper end portion of the leaf spring and an engaging portion for engaging with an opening of the leaf spring. 2. The thermal line printer according to 1.