JPH10315567A - Thermal line printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a thermal line printer which can press a thermal head into touch with a platen with a uniform pressure all over a print area. SOLUTION: One sheet of plate of a suitable length and a suitable breadth is bent to form a head-pressing leaf spring 4 having both an elastic body and a rigid body. The leaf spring is mounted to a frame 1, so that a uniform elastic force is applied to the whole of a thermal head. A head release lever 6 is fixed to one end of an eccentric head release plate 5 and arranged between the thermal head 3 and head-pressing leaf spring 4. When the head release plate 5 is turned via the head release lever 6, the elastic force of the head-pressing leaf spring 4 is transmitted or released to the thermal head 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact line type thermal printer, and more particularly to a thermal line printer having a head pressure spring structure.

[0002]

2. Description of the Related Art A conventional example of a general small-sized thermal line printer using a line type thermal head will be described with reference to a perspective view shown in FIG. In the drawing, the conventional printer structure includes a platen 2 rotatable forward and reverse on a frame 21.
3 and a thermal head 27 pressed against the platen 23
A head pressure coil spring 29a, 29b for elastically pressing the thermal head 27 against the platen 23; a head pressure spring receiving plate 34 for receiving the repulsive force of the head pressure coil springs 29a, 29b; A head release shaft 31 for detaching the thermal head 27 from the platen 23 at the time of maintenance such as a paper jam or cleaning of the thermal head 27, and a head release lever 30 fixed to one end of the head release shaft 31
And an E-ring 33 for preventing the head release shaft 31 from falling off the frame 21.

[0003]

In a small printer using a line type thermal head, it is necessary to press the thermal head against the platen with a uniform pressure over the entire printing range from the viewpoint of print quality.

Therefore, in the conventional printer having the above-described structure, a structure in which the elastic force of one coil spring as a head pressure spring is swingably arranged around a fulcrum so as to uniformly act between the platen and the thermal head, A plurality of coil springs having a uniform elastic force are arranged at appropriate positions on the back surface of the thermal head so as to eliminate uneven pressure contact between the platen and the thermal head.

As a result, the unevenness of the pressure contact between the platen and the thermal head is improved. However, the thermal head has an opening / closing mechanism for paper jam or maintenance with respect to the platen. The coil springs are repeatedly expanded and contracted each time the head is opened and closed due to the design so that an appropriate elastic force is applied when it comes into contact with the platen.As a result, deterioration such as settling of the spring occurs. In the case of the printer used, variations in elastic force occur for each coil spring, and the pressure contact force between the platen and the thermal head changes partially, resulting in problems such as deterioration in print quality and compression of the coil spring when the head is raised. As a result, the repulsive elastic force increases, and the head pressure spring receiving plate receiving the large repulsive elastic force and the machine of the head release shaft Problems such as difficulty in designing small printers in terms of structure and strength, as well as problems such as increased wear at the abutment due to partial contact between the coil spring and the head release plate. In addition, the use of a built-in and troublesome coil spring reduces the efficiency of assembly work, complicates the structure around the head pressure spring of a small printer, and increases the cost of the small printer. There were problems such as the ineffective use of paper and the detection of paper jams.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem, further improve the printing quality, realize a smaller and simpler configuration, and improve the efficiency of assembly work.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a head pressure plate spring for pressurizing a head is formed by bending a single plate having an appropriate length and width to form an elastic body and a rigid body. Are formed in a head pressure plate spring, and the head pressure plate spring is mounted on a frame so that a uniform elastic force is applied to the entire thermal head.

The head release lever is fixed to one end of the eccentric head release plate, is disposed between the thermal head and the head pressure plate spring, and rotates the head release plate via the head release lever. The transmission or release of the elastic force of the head pressure plate spring to the thermal head is performed by the head release plate and the head pressure plate spring in contact with the entire lengthwise direction when the transmission is released. The wear is reduced, and the partial deterioration of the elastic force is reduced.

Further, the head up of the thermal head for paper jam, maintenance, etc. is performed so that the head pressure plate spring and the thermal head are caught at both ends so that the head is raised and lowered in parallel with the platen. It was made.

In addition, paper detection means are provided on the paper insertion side and the paper discharge side of the recording section of the thermal head so that paper jamming and effective use of paper can be performed.

According to the structure of the present invention, a plate spring having a combination of an elastic body obtained by bending a single plate and a rigid body is used as the head pressure spring, and the repulsive elastic force of the elastic force pressed against the thermal head is used. Is received by a rigid body, the entire thermal head can be elastically pressed against the platen simply by attaching the leaf spring to the frame, and the thermal head can be uniformly pressed against the platen.

The head release lever is fixed to one end of the eccentric head release plate, and easily fits into the partition of the frame and rotates. The head release lever is installed between the thermal head and the head pressure plate spring. By rotating the head release plate via the head release lever, the elastic force of the head pressure plate spring is transmitted to or released from the thermal head, and contacts the head pressure plate spring in the entire lengthwise direction. As a result, partial deterioration of the head pressure plate spring can be reduced. Further, the head leaf spring and the thermal head have a mechanism to engage with each other, and the thermal head automatically separates from the platen when transmission is released. The head pressure plate spring is brought into contact with the eccentric side end surface of the head, and the rotation is stopped and held by the elastic force of the head pressure plate spring.

As a result, the configuration of the small printer can be simplified, and the efficiency of assembly work can be improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a frame, a platen which is rotatably supported on the frame by forward and reverse rotation, and which is vertically movably supported by bearings at both ends of the platen. A thermal line head that presses the platen to record print data on recording paper sandwiched between the platen, a head release lever that rotates on the frame, and a head release plate that is fixed to the head release lever. A thermal line printer having a configuration in which a head pressure plate spring having an elastic force for pressing the thermal line head against the platen is mounted on the frame, and the entire thermal line head is elastically mounted on the platen with an extremely simple configuration. It has the effect of being able to be pressed in a targeted manner.

According to a second aspect of the present invention, the head pressure plate spring for pressurizing the head is formed by bending a single plate having an appropriate length and width so as to combine an elastic body and a rigid body. A thermal line printer having a configuration in which an elastic force for pressing the thermal line head and a rigid force for receiving an opposing repulsive elastic force are combined. It can be mounted without the need for a receiving member, has a simplified configuration, and has the effect of improving the efficiency of assembly work.

According to a third aspect of the present invention, a plurality of slits are formed in a length direction of a head pressure plate spring for pressing a thermal line head, and the plurality of elastic members are separated by separating the elastic members. A thermal line printer constituted by a head pressure plate spring has an effect that a uniform elastic force can be applied to the thermal line head.

According to a fourth aspect of the present invention, the thermal line head and the head pressure plate spring have a mechanism to be engaged with each other, and the head release lever that rotates on the frame is provided with an eccentric head release plate. A thermal line printer in which the head release plate is fixedly arranged between the thermal line head and the head pressure plate spring, and the head release plate is rotated through the head release lever, thereby This has the effect that the thermal line head can be automatically separated from the platen.

According to a fifth aspect of the present invention, the head release plate is rotated through a head release lever to transmit and release the elastic force of the head pressure plate spring to and from the thermal line head. A thermal line printer configured to hold the elastic force of the head pressure plate spring over the entire eccentric side end surface of the head release plate at the time of release, and to stop the rotation. The contact between the plate and the head pressure plate spring in the entire lengthwise direction has an effect that mechanical wear can be reduced and partial deterioration of elastic force can be suppressed.

According to a sixth aspect of the present invention, there is provided a head release lever which rotates on a frame, a lever portion being provided on a side surface of a rotating portion, an elastic body being provided on an opposite side surface, and a projecting portion being provided on a tip portion of the elastic body. A thermal line printer having a configuration in which the partition of the frame is sandwiched between the lever portion of the head release lever and the protrusion of the elastic body by being inserted and fitted into a hole provided in a partition on the side surface of the frame. In addition, it is possible to prevent falling off without using parts such as E-ring as in the related art, and it is possible to easily insert and fit into the frame, thereby improving the assembling work efficiency.

According to a seventh aspect of the present invention, a means for detecting a recording paper pinched and pressed between a thermal line head and a platen or a marker of the recording paper includes a recording paper of the thermal line head. It is a thermal line printer with a configuration that is installed on the insertion side and discharge side in the traveling direction,
It has the effect that paper jam and effective use of paper can be achieved.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a plan view showing an embodiment of the present invention. In FIG. 1, a frame 1 which forms a basis of a printer and a platen which is A line-type thermal head 3 that elastically abuts on the recording paper 15 sandwiched between the platen 2 to record print data; a head pressure plate spring 4 corresponding to a conventional head pressure spring; A head release plate 5 for releasing the head pressure plate spring 4, a head release lever 6 fixed to one end of the head release plate 5 and rotating, and a gear train 14
, A motor 13 for rotating the platen 2, a photosensor 7 for detecting the insertion side of the recording paper 15, and a recording paper 1
5 comprises a photo sensor 8 for detecting the discharge side.

The platen 2 is rotatably supported at both ends of a rotation center shaft at predetermined positions of the frame 1 so as to be capable of normal and reverse rotation. One end of the shaft receives rotational power from a motor 13, so that a gear train 14 is formed. The recording paper 15 sandwiched between the recording head 15 and the thermal head 3 is arranged so as to be appropriately conveyed by the rotational power of the motor 13.

The thermal head 3 is a line type thermal head, and a heating element 3a of the thermal head 3 (see FIGS. 2 and 3).
Both ends of the head pressure plate spring 4 are provided with key portions 3c and 3d which are engaged with the holes 4a and 4b of the head pressure plate spring 4 at both ends thereof. Further, a seat 3b (see FIGS. 2 and 3) is provided at the center of the width direction end, and is supported by a convex portion 1a of the frame 1 (see FIGS. 2 and 3).

The head pressure plate spring 4 is formed by bending a single plate to combine an elastic body and a rigid body and form ears 4c and 4d (see FIG. 5) at both ends in the longitudinal direction of the rigid body. Holds when mounted on. Further, the thermal head 3 is elastically pressed in the direction of the platen 2 by being mounted on the frame 1. In this embodiment, holes 4a and 4b for engaging the key portions 3c and 3d of the thermal head 3 and the head pressure plate spring 4 are provided at both ends of the contact portion of the tip of the head pressure plate spring 4 with the thermal head 3, and the thermal head 3 is provided. A plurality of slits are provided to apply a predetermined elastic force to the head 3. Further, the rigid body of the head pressure plate spring 4 may have a configuration in which another member is used instead.

The head release plate 5 is formed in an eccentric plate shape and is located near the thermal head 3.
The head release lever is fixed to one end of the frame 1 and is rotatably supported by the frame 1.
A small piece with elasticity is part of the head release lever,
A projection 6a is provided at the tip of the small piece to prevent it from falling off after insertion and fitting.

The photo sensor 7 is soldered to the FPC 11 and is mounted on the frame 1 near one end of a sensor mounting plate 10 arranged in parallel with the platen so as to be on the recording paper 15 insertion side. Also, the photo sensor 8
Attached near the one end of the sensor mounting plate 10 which is soldered to the FPC 11 and arranged in parallel with the platen on the frame 1 so as to be on the paper discharge side of the recording paper 15 and prints with or without recording paper or on recording paper There is a marker that was
The absence is electrically detected.

Next, the operation of this embodiment will be described. FIG. 2 and FIG. 3 are schematic sectional views of the printer according to the present embodiment. 2 shows a head-down state in which the thermal head 3 is elastically pressed against the platen 2 by the head pressure plate spring 4. FIG. 3 shows a head-up state in which the elastic force of the head pressure plate spring 4 is released from the thermal head 3. The state is shown. FIG. 4 shows a state of the head release lever 6 fixed to one end of the head release plate 5.

In the normal printing state shown in FIG. 2, the thermal head 3 has a head pressure plate spring
This indicates that the printing portion is elastically held in a state where the printing portion is pressed against the platen 2 by the elastic force, and is in a printing operable state.

On the other hand, when it is necessary to release the pressing force of the thermal head 3 against the platen 2 in order to release an obstacle such as a paper jam occurring during the printing operation, as shown in FIG. In order to release the pressure of the head pressure plate spring 4, the head release lever 6 fixed to one end of the head release plate 5 is rotated to release the pressure contact force of the head pressure plate spring 4 against the thermal head 3. At the same time, the holes 4a, 4b of the head pressure plate spring 4 and the keys 3c, 3d of the thermal head 3 are engaged with each other, so that the thermal head 3 is brought into the head-up state together with the turning operation of the head release lever 6. In the head-up state holding, the holding and the rotation stop are performed by receiving the elastic force of the head pressure plate spring 4 over the entire eccentric side end surface of the head release plate 5. 3 is released from the elastic pressure of the head pressure plate spring 4.

A printer control unit (not shown) performs electric signals from the photosensor 7 on the paper insertion side and the photosensor 8 on the paper discharge side via the FPC 11. The operation description is defined as ON when the photo sensor determines that there is paper, and OFF when it is determined that there is no paper. If the photo sensor 7 on the paper insertion side and the photo sensor 8 on the paper discharge side are determined, Is also OFF, the paper is not loaded in the printer. When the photo sensor 7 on the paper insertion side is ON and the photo sensor 8 on the paper discharge side is OFF, the paper is attached to the printer but does not reach the discharge side. When both the photo sensor 7 on the paper insertion side and the photo sensor 8 on the paper discharge side are ON, the paper is in a state of being mounted on the printer. When the photo sensor 7 on the paper insertion side is OFF, the photo sensor 8 on the paper discharge side is turned off.
Is ON, paper is loaded on the printer but not on the insertion side. Photo sensor 7 and photo sensor 8
By detecting the ON and OFF electric signals, the conveyance state such as paper jamming can be determined. Alternatively, the recording paper 15 is conveyed to the cutter after the data is printed and cut. The conveyance of the paper after the printing is useless, but there is no means for easily back feeding. By back feeding the photo sensor 8 on the paper discharge side this time, the recording paper 15 can be efficiently used.

As described above, the thermal head is configured to be pressed by the head pressure plate spring in the longitudinal direction thereof with uniform elasticity over the entire area, thereby realizing a highly accurate small printer with a simple structure. Can be done. Also, by realizing pressure contact of the thermal head by the head pressure plate spring, the structure is simplified as compared with a conventional pressure contact structure of a thermal head. Also, when configuring printers having different recording paper widths, it is possible to design with similar components.

[0032]

As described above, according to the present invention, a head pressure plate spring capable of applying an elastic force to the thermal head with a uniform pressure and a head release plate for releasing the head pressure plate spring entirely are provided. With this arrangement, a small printer with an extremely simple configuration can be realized.Furthermore, such as a head release lever and a head pressure plate spring, the assembling workability is excellent, printing quality is stable, and paper jamming is possible. A printer capable of detection can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a printer according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state in which the thermal head of the printer according to the embodiment is pressed.

FIG. 3 is a cross-sectional view showing the thermal head released state of the printer according to the embodiment;

FIG. 4 is a partial view of a head release lever of the printer according to the embodiment;

FIG. 5 is a perspective view of a head pressure plate spring of the printer according to the embodiment.

FIG. 6 is a perspective view showing a configuration of a conventional thermal printer.

[Explanation of symbols]

 Reference Signs List 1 frame 1a convex portion 2 platen 3 thermal head 3a heating element 3b seat 3c, 3d key portion 4 head pressure plate spring 4a, 4b hole 4c, 4d ear portion 5 head release plate 6 head release lever 6a convex portion 7 photo sensor 8 photo sensor 9 Bearing 10 Sensor mounting plate 11 FPC 13 Motor 14 Gear train 15 Recording paper

Claims (7)

[Claims] 1. A frame, a platen supported by the frame so as to be rotatable forward and backward, and vertically supported by both end bearings of the platen so as to be vertically movable and held between the platen by pressing against the platen. A thermal line head for recording print data on recording paper, a head release lever rotating on the frame, a head release plate fixed to the head release lever, and an elasticity for pressing the thermal line head against the platen. A thermal line printer, wherein a head pressure plate spring having a force is mounted on the frame. 2. A thermal head according to claim 1, wherein the head pressure plate spring has a structure in which the elastic force for pressing the thermal line head and the rigid force for receiving the opposing repulsive elastic force are combined. Line printer. 3. An elastic body is formed in a plurality of slits in a length direction of pressing a thermal line head of a head pressure plate spring to form a separate elastic body, and a uniform elastic force is applied to the thermal line head. Item 4. The thermal line printer according to item 1. 4. A thermal line head and a head pressure plate spring have a mechanism to engage with each other, and an eccentric head release plate is fixed to a head release lever rotatably fitted to a frame. Arranged between the thermal line head and the head pressure plate spring, rotating the head release plate via the head release lever,
2. The thermal line printer according to claim 1, wherein the thermal line head is automatically separated from the platen. 5. A head release plate is rotated via a head release lever to transmit and release the elastic force of the head pressure plate spring to the thermal line head. When the transmission is released, the elastic force of the head pressure plate spring is released. 2. The thermal line printer according to claim 1, wherein the head is held and the rotation is stopped over the entire eccentric end surface of the head release plate. 6. A lever portion is provided on a side surface of a rotating portion of a head release lever which rotates on a frame, an elastic body is provided on an opposite side surface, and a projecting portion is provided on a tip portion of the elastic body. 2. The frame according to claim 1, wherein the frame is inserted and fitted into the hole provided, and the partition of the frame is sandwiched between the lever portion of the head release lever and the projection of the elastic body, thereby providing insertability and preventing falling off. The thermal line printer as described. 7. A means for detecting a recording sheet or a marker of the recording sheet pressed and pressed between the thermal line head and the platen is provided on an insertion side and a discharge side in the direction of travel of the recording sheet of the thermal line head. The thermal line printer according to claim 1, wherein