JPH10250122A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a thermal head from rattling in an axial direction of a platen and maintain a relative positional relationship between the thermal head and platen favorably, by pressing a side part of the thermal head by a positioning member and positioning the thermal head at a predetermined position in the axial direction of the platen. SOLUTION: A fixing jig 10 comprises a cylindrical body 21 fixed to a head- supporting member 6 by screws 20, a pressing part 22 having a rear end fitted in the cylindrical body 21 in a movable state and a leading end formed in a hemispheric body, and a coil spring 23 urging the pressing part 22 in a direction to project. While a thermal printer 1 is closed, the pressing part 22 of the fixing jig 10 is in touch with a main frame 2 and pressed into the cylindrical body 21 in spite of an urging force of the coil spring 23. The fixing jig 10 is interposed between the thermal head 5 and the main frame 2, so that the thermal head 5 is prevented from rattling in an axial direction of a platen 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer having a thermal head for use in thermal recording, and more particularly to a thermal printer capable of multicolor recording in which the thermal head is positioned at a predetermined position in order to obtain good image quality. It is about.

[0002]

2. Description of the Related Art A thermal head used for thermal recording has a glaze portion arranged in the direction of the center axis of rotation of a platen, and prints on a recording material interposed between the platen and the glaze portion. The heater formed on the glaze portion corresponding to the image to be selected is selectively heated, and the image is thermally transferred to the image receiving surface of the recording material via the toner ribbon.

[0003] As shown in FIG.
Are supported by a sub-frame 51 and have head support members 52 at both ends. A platen 53 is arranged below the thermal head 50. The platen 53 is a columnar member, and is rotatably attached to the main frame 56 via platen shafts 54 at both ends.

[0004]

However, the above-mentioned conventional thermal head 50 has a mounting structure having mobility so as to be able to move up and down, so that it is several μm to several tens μm in the direction of the arrow in FIG. As a result, the relative positional relationship between the thermal head 50 and the platen 53 may deviate, and a color deviation may occur in an image thermally transferred to the image receiving surface of the recording material. In particular, "variable dot size method" or "dither method" that expresses gradation by area ratio
In color printers.

In order to prevent the relative positional deviation between the thermal head and the platen, a thermal printer having a positioning member provided on the thermal head side is known. As shown in FIG. 10, bearings 58 are attached to head shafts 57 at both ends of the thermal head 50, and the bearings 58 are supported by cut portions of the main frame 56 so as to be vertically movable. In addition, bearing 5
A projection (positioning member) 59 is provided on 8. The cut portions of the main frame 56 are covered with sheet metals 60 and 61 provided outside the main frame 56, and the sheet metals 60 and 61 come into contact with the protrusion 59. Sheet metal 6
0 and 61 indicate that the contact force changes at the upper and lower positions of the thermal head 50, and when the thermal head 50 is at the recording position,
The biasing force of the protrusion 59 is increased to position the thermal head 50 (FIG. 10A). When the thermal head 50 deviates from the recording position, the bias of the protrusion 59 is weakened to release the thermal head 50. I do.

However, when the positioning member is provided so as to protrude from the side surface of the thermal head which moves up and down, there is a problem that the place for mounting the mechanical parts on the main body is limited. That is, usually, it is necessary to provide a bar or the like for removing jammed paper near the platen on the main body side, but projecting members at both ends of the thermal head are provided so as not to interfere with other parts when the thermal head moves up and down. There must be a passage for movement. For this reason, the place where the bar is attached is limited. Further, since the thermal head is positioned by the contact force of the sheet metal, when the thermal head is moved up and down, the load increases due to the contact force, and a considerable force is required.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and prevents the relative positional relationship between the thermal head and the platen from shifting, thereby preventing the occurrence of color shift in an image thermally transferred to an image receiving surface of a recording material. An object of the present invention is to provide a printer and improve image quality.

[0008]

In order to achieve the above object, a thermal printer according to the present invention has a structure in which a recording material is interposed between a thermal head and a platen, and an image is formed on an image receiving surface of the recording material. In a thermal printer for performing thermal transfer, a positioning member for positioning the thermal head at a predetermined position in the platen axial direction by applying a force from a side of the thermal head is provided on a main frame supporting the platen, and the thermal head and the thermal head are provided. Maintain the relative position with the platen. In the thermal printer configured as described above, the thermal head can be pressed at the predetermined position in the platen axial direction by pressing the side portion of the thermal head with the positioning member, and the play of the thermal head in the axial direction of the platen can be prevented. Therefore, the relative positional relationship between the thermal head and the platen can be suitably maintained. Thereby, it is possible to improve the image quality by preventing the occurrence of color misregistration in the image thermally transferred to the image receiving surface of the recording material. Further, since the positioning member is attached to the main frame, even when the thermal head is moved up and down, it does not interfere with other components.

Another configuration of the thermal printer according to the present invention is a thermal printer in which a recording material is interposed between a thermal head and a platen, and an image is thermally transferred to an image receiving surface of the recording material. A positioning member provided on at least one of a main frame supporting the platen, wherein the positioning member has a cylindrical body, a rear end movably housed in the cylindrical body, and a pressing end projecting from the cylindrical body. And a biasing member provided in the cylinder and biasing the pressing portion in a direction to protrude from the cylinder. When the thermal head is set at a recording position, the positioning member is The pressing portion is disposed between the head and the main frame, and is pressed into the cylinder against the urging force of the urging member.
Since the positioning member having such a configuration has a simple configuration, it is possible to prevent color shift from occurring in an image thermally transferred to an image receiving surface of a recording material at low cost and improve image quality. Further, since the thermal head and the main frame are positioned by the urging force, when the thermal head is moved up and down, the thermal head is slightly moved in the axial direction to reduce the load, and the thermal head is easily moved up and down.

Still another configuration of the thermal printer according to the present invention is a thermal printer in which a recording material is interposed between a thermal head and a platen and an image is thermally transferred to an image receiving surface of the recording material. An elastic member as a positioning member for positioning the thermal head at a predetermined position in the platen axial direction by applying a force from a side is provided on at least one of the thermal head and the main frame supporting the platen, and the thermal head is recorded. When set at the position, the elastic member is disposed between the thermal head and the main frame supporting the platen, and the relative position between the thermal head and the platen is maintained by the elastic force of the elastic member. Since the fixing jig thus configured has a simple configuration, it is possible to prevent the occurrence of color misregistration in the image thermally transferred to the image receiving surface of the recording material at low cost and improve the image quality. further,
Since the thermal head and the main frame are positioned by the urging force, when the thermal head is moved up and down, the thermal head is slightly moved in the axial direction to reduce the load, and the thermal head is easily moved up and down.

Still another configuration of the thermal printer according to the present invention is a thermal printer in which a recording material is interposed between a thermal head and a platen and an image is thermally transferred to an image receiving surface of the recording material. A positioning member that applies a force from the side to position the thermal head at a predetermined position in the platen axial direction; the positioning member includes a taper portion that is coaxially arranged with the platen and that is inclined in the axial direction; A platen bearing for supporting the lower surface of the thermal head, wherein the thermal head is attached to both side surfaces thereof and abuts on the platen shaft to position the thermal head in a direction perpendicular to the platen axis. The thermal head is supported by a head support member having a longer extending piece, and the thermal head When set, the thermal head piece of the head support member by downward force applied to the thermal head is moved to the axial position not slip the tapered portion is axially positioned. This bearing preferably has a bearing structure so that it can rotate about the platen shaft. The platen bearing thus configured can position the thermal head at a predetermined position in the axial direction by providing a tapered portion by a lateral force generated when the thermal head is set at the recording position. Further, since the problem can be solved only by changing the shape of the platen bearing originally provided, the assembling cost does not increase.

Still another configuration of the thermal printer according to the present invention is a thermal printer in which a recording material is interposed between a thermal head and a platen and an image is thermally transferred to an image receiving surface of the recording material. An actuator as a positioning member for positioning the thermal head at a predetermined position in the axial direction of the platen by applying a force from a side is provided on at least one of the thermal head and a main frame supporting the platen, and the thermal head is positioned at a recording position. When the actuator is set to the position, the actuator is disposed between the thermal head and the main frame supporting the platen, and the relative position between the thermal head and the platen is maintained by the operation of the actuator. The actuator configured in this way prevents the thermal head from moving in the axial direction with a very strong force during operation, and does not apply any force to the thermal head when not in operation. Can be done. By providing an actuator on one side of the thermal head and another positioning member on the other side, the thermal head can be reliably positioned.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a thermal printer according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing a state where a thermal printer according to the present invention is opened. The thermal printer 1 includes a main frame 2 and pins 3 (FIG. 4A, FIG.
(A) A sub-frame 4 is supported to be openable and closable about a fulcrum, and a thermal head 5 is provided on the sub-frame 4. The thermal head 5 has head support members 6 and 7 at the left and right ends, respectively (see FIG. 2 for the left head support member 7). The right head support member 6 is provided with a fixing jig 10 as a positioning member. The fixing jig 10 will be described in detail with reference to FIG.

FIG. 2 is a perspective view showing a state in which the thermal printer according to the present invention is closed. The thermal head 5 is a member formed in a substantially rectangular shape, and a platen 12 is disposed below the thermal head 5. The platen 12 is a columnar member, and is rotatably attached to the main frame 2 via a platen shaft 13 (only the right side is shown) protruding from both ends. Bearings 14 are attached to the platen shafts 13 at both ends, respectively. On the head support members 6 and 7 attached to the thermal head 5, pieces 6 for abutting the bearings 14 and positioning in a direction orthogonal to the platen axis are provided.
a and 7a are extended.

The thermal head 5 has a glaze portion 15 disposed on the lower surface thereof in parallel with the platen 12.
2 and a recording material (not shown) inserted between the glaze portion 15 and a heater formed on the glaze portion 15 corresponding to an image to be printed is selectively heated by a toner ribbon (not shown). ), The image is thermally transferred to the image receiving surface of the recording material.

FIG. 3 is a sectional view taken along line AA of FIG. The fixing jig 10 includes a cylinder 21 fixed to the head support member 6 with a screw 20, a pressing portion 22 having a rear end movably mounted in the cylinder 21 and a hemispherical tip, and a pressing portion. 2
And a coil spring 23 that urges the coil spring 2 in the direction in which it projects. 2, when the thermal printer 1 is closed, the pressing portion 22 hits the main frame 2 and is pushed into the cylindrical body 21 against the urging force of the coil spring 23, as shown in FIG. State. By interposing the fixing jig 10 between the thermal head 5 and the main frame 2, it is possible to prevent the thermal head 5 from rattling in the axial direction of the platen 12. Since the pressing portion 22 is movable in the direction of the platen axis, the fixing jig 10 does not hinder the opening and closing of the thermal printer 1.

Next, the operation of the thermal printer 1 according to the present invention will be described. 4 and 5 are explanatory views of the operation of the thermal printer according to the present invention. In FIG. 4A, the shaft 3
And the thermal head 5
Is moved in the direction of arrow a. In FIG. 4B, the pressing portion 22 of the fixing jig 10 contacts the opening end 2 a of the main frame 2. In this case, the pressing portion 22 protrudes outward by L from the inner surface of the main frame 2 by the urging force of the coil spring 23 (see FIG. 3).

FIG. 5A shows the state of the shaft 3 from the state of FIG.
, The sub-frame 4 is further closed with the fixing jig 10 disposed inside the main frame 2. At this time, the pressing portion 22 of the fixing jig 10
The cylindrical body 21 resists the urging force of the coil spring 23 (see FIG. 3).
(See FIG. 3), and is brought into contact with the inner surface of the main frame 2.

FIG. 5B shows that the pressing portion 22 is a coil spring 2.
3 (see FIG. 3) against the urging force of the cylinder 3 (see FIG. 3).
Shows the state of being pushed inside. By interposing the fixing jig 10 between the thermal head 5 and the main frame 2, a force for pressing the thermal head 5 in the direction of the arrow b is generated, whereby the thermal head 5 is positioned at a predetermined position in the axial direction. With the platen 12 of the thermal head 5
Backlash in the axial direction can be prevented. Therefore, the relative positional relationship between the thermal head 5 and the platen 12 can be suitably maintained. Thereby, it is possible to improve the image quality by preventing the occurrence of color misregistration in the image thermally transferred to the image receiving surface of the recording material.

FIG. 6 is a front view showing another embodiment of the thermal printer according to the present invention. In the above-described embodiment, the case where the fixing jig 10 is attached to the head support member 6 of the thermal head 5 and the relative positional relationship between the thermal head 5 and the platen 12 is appropriately maintained has been described. The same effect can be obtained by attaching the tool 10 to the main frame 2.

In the above embodiment, the fixing jig 10
Has been described, the case where the relative positional relationship between the thermal head 5 and the platen 12 is appropriately maintained has been described.
The thermal head 5 is made of an elastically deformable member such as rubber.
To maintain the relative positional relationship between the thermal head 5 and the platen 12 suitably.

FIG. 7 is a front view showing still another embodiment of the thermal printer according to the present invention. In this embodiment, the thermal head 5 is closed with the thermal printer closed.
A solenoid 25 as an actuator is provided at a position where a force is applied from the side of the head support member 6. FIG.
(A) shows a state in which the thermal printer is open, and in this state, the solenoid 25 is not operated.
On the other hand, as shown in FIG. 7B, when the thermal printer is closed, the solenoid 25 is operated to
a, and urges the head support member 6 of the thermal head 5 from the side. Thereby, the relative positional relationship between the thermal head 5 and the platen 12 can be suitably maintained.
In the embodiment described above, positioning is performed from only one side, but positioning may be performed from both sides. In that case, the left and right embodiments may be different.

FIG. 8 is a front view showing still another embodiment of the thermal printer according to the present invention. In this embodiment, the platen 12 is attached to the main frame 2 via a platen shaft 13. A platen bearing 28 having a tapered portion 27 inclined in the platen direction is attached to the platen shaft 13, and an end of the tapered portion 27 is connected to the bearing 14.

FIG. 8A shows a state in which the thermal printer is opened. In this state, the head supporting member 6 of the thermal head 5 comes into contact with the tapered portion 27 of the platen bearing 28. Then, as shown in FIG. 8B, when the thermal head is closed and the thermal head 5 is pushed from above, the head support member 6 in contact with the tapered portion 27 of the platen bearing 28 starts to slide in the lateral direction. And is positioned on the bearing 14. Thus, when the thermal printer is closed and pushed by the thermal head 5 from above,
A force is applied from the side of the thermal head 5, so that the relative positional relationship between the thermal head 5 and the platen 12 can be suitably maintained. In this case, the positioning jig of the above-described embodiment may be provided on the opposite side. In particular, it is preferable to use a taper type on one side and a solenoid type on the other side, since the positioning can be surely performed.

In the above, the configuration of the thermal transfer type color printer has been described as an example.
For example, the present invention can be applied to a color printer using Thermo Autochrome Paper manufactured by Fuji Photo Film Co., Ltd. Further, even if the print is monochrome, the present invention can be applied to a case where a multicolor print is created using the print as a plate. For example, a thermal imagesetter using a transparent heat-sensitive film, a thermal platesetter using a plate whose lipophilicity changes by heat, and the like correspond to this case.

[0026]

As described above in detail, according to the thermal printer of the first aspect of the present invention, the thermal head is positioned at a predetermined position in the platen axial direction by pressing the side of the thermal head with the positioning member. In addition, the play of the platen of the thermal head in the axial direction can be prevented. Therefore, the relative positional relationship between the thermal head and the platen can be suitably maintained. Thereby, it is possible to improve the image quality by preventing the occurrence of color misregistration in the image thermally transferred to the image receiving surface of the recording material. Further, since the positioning member is attached to the main frame, even when the thermal head is moved up and down, it does not interfere with other components.

According to the thermal printer according to the second and third aspects of the present invention, since the configuration of the positioning member is simple, it is possible to prevent the occurrence of color misregistration in the image thermally transferred to the image receiving surface of the recording material at low cost. Thus, the image quality can be improved. Further, since the thermal head and the main frame are positioned by the urging force, when the thermal head is moved up and down, the thermal head is slightly moved in the axial direction to reduce the load, and the thermal head is easily moved up and down.

According to the thermal printer according to the fourth aspect of the present invention, by providing the taper portion on the platen bearing, the thermal head is moved in the axial direction by a lateral force generated when the thermal head is set at the recording position. It can be positioned at a predetermined position. Further, since the problem can be solved only by changing the shape of the platen bearing originally provided, the assembling cost does not increase.

According to the thermal printer according to the fifth aspect of the present invention, the actuator prevents the thermal head from moving in the axial direction by a very strong force during operation, and does not apply any force to the thermal head during non-operation. Since no force is applied, the thermal head can be easily moved up and down.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a thermal printer according to the present invention is opened.

FIG. 2 is a perspective view showing a state in which the thermal printer according to the present invention is closed.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a diagram illustrating the operation of the thermal printer according to the present invention.

FIG. 5 is a diagram illustrating the operation of the thermal printer according to the present invention.

FIG. 6 is a front view showing another embodiment of the thermal printer according to the present invention.

FIG. 7 is a front view showing another embodiment of the thermal printer according to the present invention.

FIG. 8 is a front view showing another embodiment of the thermal printer according to the present invention.

FIG. 9 is a front view showing a conventional thermal printer.

FIG. 10 is a view showing a positioning member of a conventional thermal printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal printer 2 Main frame 5 Thermal head 6 Head support member 7 Recording material 10 Fixing jig 12 Platen 13 Platen shaft 14 Bearing 21 Cylindrical body 22 Pressing part 23 Coil spring 25 Solenoid 27 Taper part 28 Platen bearing

Claims (5)

[Claims] 1. A thermal printer in which a recording material is interposed between a thermal head and a platen and an image is thermally transferred to an image receiving surface of the recording material. A thermal printer, wherein a positioning member for positioning at a predetermined position in the platen axial direction is provided on a main frame supporting the platen, and a relative position between the thermal head and the platen is maintained. 2. A thermal printer for interposing a recording material between a thermal head and a platen and thermally transferring an image to an image receiving surface of the recording material, wherein at least one of the thermal head and a main frame supporting the platen. A positioning member provided in the cylinder, the positioning member comprising: a cylinder; a pressing portion having a rear end movably housed in the cylinder and a tip protruding from the cylinder; and a positioning member provided in the cylinder. A biasing member for biasing the pressing portion in a direction to protrude from the cylindrical body, wherein when the thermal head is set at a recording position, the positioning member is disposed between the thermal head and the main frame. The pressing portion is pushed into the cylinder against the urging force of the urging member. 3. A thermal printer in which a recording material is interposed between a thermal head and a platen, and an image is thermally transferred to an image receiving surface of the recording material. An elastic member as a positioning member for positioning at the predetermined position in the platen axial direction is provided on at least one of the thermal head and the main frame supporting the platen, and when the thermal head is set at a recording position, the elastic member is A thermal printer, which is disposed between a thermal head and a main frame supporting the platen, and maintains a relative position between the thermal head and the platen by an elastic force of the elastic member. 4. A thermal printer in which a recording material is interposed between a thermal head and a platen, and an image is thermally transferred to an image receiving surface of the recording material. A positioning member for positioning the platen at a predetermined position in the axial direction of the platen, wherein the positioning member is a platen bearing for supporting the platen with a tapered portion coaxially arranged with the platen and inclined in the axial direction; A head support member having a piece attached to both side surfaces thereof and extending from a lower surface of the thermal head for abutting on the platen axis and positioning the thermal head in a direction perpendicular to the platen axis; When the thermal head is set at the recording position, the thermal head is Thermal printer characterized in that said thermal head moves pieces of the head support member to the axial position not slip the tapered portion is axially positioned by the force of the direction. 5. A thermal printer in which a recording material is interposed between a thermal head and a platen, and an image is thermally transferred to an image receiving surface of the recording material. An actuator as a positioning member for positioning at a predetermined position in the platen axial direction is provided on at least one of the thermal head and a main frame supporting the platen, and when the thermal head is set at a recording position, the actuator is mounted on the thermal head. And a main frame supporting the platen and maintaining the relative position between the thermal head and the platen by the operation of the actuator.