JPH084301Y2 - Printhead body mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of Invention] <Industrial Application Field> The present invention relates to a mounting structure of a print head body pivotally supported by a carriage so as to be rotatable toward and away from a platen.

<Prior Art> Conventionally, as a print head, for example, a thermal head is used to perform heat-sensitive or thermal transfer printing on an object to be printed.In a thermal head printing apparatus having such a structure, the thermal head is inserted via a carriage. There is a serial printing method in which printing is performed by moving the platen along a platen. Generally, a print head body is composed of a head holder supported by a carriage and a thermal head fixed to the head holder. At the time of printing, the platen receives the object to be printed, and the thermal head is the object to be printed. After the completion of printing, the thermal head is moved away from the printing object in order to carry out the printing object.

By the way, in the printing apparatus having the above structure, the thermal head must be removed from the carriage when the thermal head is replaced due to deterioration or the like. It is difficult to remove and attach a new head. In that case, a specialized worker will be asked to perform replacement work, or the complete equipment will be sent back to a service factory, etc., but the work cost will rise, and the operating time due to unavailability during work will be reduced. Since the problem of large loss occurs, it is desirable that the user can easily replace the print head body.

<Problems to be Solved by the Invention> In view of the problems of the prior art as described above, the main object of the present invention is to improve the structure for mounting the print head body so that the replacement work of the print head body can be easily performed. To provide.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the print head body is brought into contact with and separated from the platen by a carriage supported by a casing so as to reciprocate along the platen. And a carriage and the print head body, wherein the print head body is rotatably pivoted in a direction to rotate and the print head body is elastically pressed against the platen by a spring in a printing state. And a C-shaped shaft supporting hole provided on either side of the C-shaped shaft supporting hole so that the C-shaped shaft supporting hole can be inserted into and removed from the C-shaped shaft supporting hole in the radial direction through the opening and can be rotatably fitted. And a partial circular cross-section shaft portion provided on the other one of the carriage and the print head body,
The position where the shaft support hole and the shaft portion can be inserted and removed is provided on the rotation direction side of the print head body that is rotated by the elastic urging force of the spring when the platen is removed from the printing state. It is achieved by providing a mounting structure of a print head body characterized by the above.

<Operation> As described above, by using the C-shaped shaft support hole and the shaft part having the partial circular cross-section to align both the shaft support hole and the shaft part to the insertable / removable position, the print head body is attached / detached to / from the carriage. The print head body is elastically pressed against the platen during printing, and in that state the rotation of the print head body due to the elastic urging force of the print head body is restricted, and the shaft support hole and shaft part are inserted and removed. The print head body is elastically rotated by removing the platen from the printing state while not aligning with the position, and a position where the shaft support hole and the shaft portion can be inserted / removed is provided on the rotation direction side. Therefore, the positioning for insertion / removal can be quickly performed.

<Embodiment> Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a front view of an essential part of a card printing apparatus to which the present invention is applied. The printing apparatus 1 is used by being incorporated in a card reader / writer of a prepaid card, for example, and prints information such as a balance on a printing surface 2a of a card 2 as an object to be printed.

As shown in conjunction with FIG. 2 showing an exploded perspective view of the printer 1, the platen 3 is a flat plate having a flat receiving surface on the lower surface of the drawing in order to receive a surface opposite to the printing surface 2a of the card 2. It is formed into a mold. A boss portion 3a is projectingly provided on one end face of the platen 3 in the longitudinal direction, and an inverted U-shaped elastic piece 3b is integrally formed on the other end face of the platen 3.
A boss portion 3c protruding in a direction opposite to the boss portion 3a is provided on a free end portion of the elastic piece 3b. The one boss portion 3a is supported in the mounting hole 5a of the one card guide 5 fixed in the casing 4 of the card reader / writer in a retracted state, and the guide frame 6 fixed to the casing 4 is attached. The other boss portion 3c is supported in the hole 6a in a retracted state, and the elastic pieces 3b are elastically propelled in the longitudinal direction of the platen 3 to prevent both the boss portions 3a and 3c from coming off.
Are mounted in the casing 4.

The card 2 inserted in the casing 4 has a platen 3
2 is conveyed along the receiving surface of the lower surface of the paper in the front and back direction of the paper surface in FIG. 2 by the above-mentioned card guide 5 and the other card guide (not shown) facing the card guide 5. Both edges along the transport direction are guided. In addition, the guide frame 6a guides the print surface 2a side, which is the lower surface of the card 2 in the figure.

As shown in FIG. 1 showing the printing state, the platen 3
A head holder 9 is rotatably attached to a carriage 8 which is reciprocally driven in a printing direction orthogonal to the transport direction below the card 2 along a printing surface 2a of the card 2. The sloped thermal head 7 is fixed. The head holder 9 and the thermal head 7 form a print head body. Carriage 8
Is formed in a concave shape as well shown in FIG. 2. One of the opposing wall portions 8a and 8b is provided with one projecting outer wall surface and the other outer wall surface thereof is provided with two projecting projections. The arm portion 10 is guided by two linear shafts 11 arranged in parallel with each other so as to be reciprocally movable in the printing direction. Further, a lead screw shaft 13 that is parallel to the linear shaft 11 is provided, and the lead screw shaft 13 has one wall portion 8a.
A screw pin 12 provided in a convex shape is screwed, and the carriage 8 is reciprocally driven in the printing direction by selectively rotating the lead screw shaft 13 forward and backward by a motor (not shown). A boss portion 14 as a shaft portion having a partially circular cross section is provided on each of the opposing inner surfaces of both wall portions 8a and 8b of the carriage 8 so as to project in a direction along the transport direction of the card 2.

The head holder 9 is integrally formed with a pair of arm portions 9a extending from both side edges of the fixed portion of the thermal head 7, and the free ends of both arm portions 9a serve as C-shaped shaft support holes. The bearing portions 15 formed in a C shape are formed coaxially with each other. Further, the width between the outer surfaces of both arm portions 9a is made smaller than the width between the inner surfaces of both wall portions 8a and 8b of the carriage 8, and both bearing portions 15 are fitted to the corresponding boss portions 14 to A head holder 9 is pivotally supported by a carriage 8 so as to be rotatable in a direction in which the thermal head 7 comes in contact with and separates from the print surface 2a of the second print head 2a.

In the printing apparatus 1, the head holder 9 is detachably attached to the carriage 8. That is, the boss portion 14 has a partially circular cross section in which a part of the circular cross section is cut off so that the boss portion 14 has a width slightly smaller than the opening width of the opening portion 15a that is smaller than the hole diameter of the C-shaped bearing portion 15. It is formed in a shape. In this embodiment, the boss portion 14 is formed with a two-face width portion 14a composed of a pair of flat cut surfaces that are parallel to each other at diagonal positions thereof.
The bearing portion 15 and the boss portion 14 can be relatively inserted into and pulled out from each other by matching the width of the bearing portion and the opening width of the opening portion 15a with each other.

A pressing spring 16 composed of a compression coil spring is interposed between the head holder 9 and the carriage 8 to press the thermal head 7 against the platen 3 or the printing surface 2a of the card 2 at the printing position. The head holder 9 is elastically urged in the direction. An elastic tongue piece 17 is integrally formed on the lower surface of the free end portion opposite to the pivotal support portion of the head holder 9 so as to extend downward, and a penetrating hole provided on the bottom wall portion of the carriage 8 is provided. Through the hole 18, the free end portion of the elastic tongue piece 17 can project and retract below the carriage 8 as the head holder 9 rotates.

A claw portion 17a is formed at the free end of the elastic tongue piece 17 so as to project radially outward with respect to the pivot axis of the head holder 9. When the claw portion 17a projects downward from the lower surface 8c, the through hole of the carriage 8 with respect to the elastically urging direction of the head holder 9
The elastic tongue piece 17 is provided so that the claw portion 17a can be elastically displaced to the outside of the through hole 18 so that the claw portion engages with the outer lower surface 8c of the hole 18.
Is slidably in contact with the inner surface of the through hole 18 while being elastically bent.

By the way, FIG. 1 shows a printing state on the card 2, and FIG. 3 shows both a state before the thermal head 7 is printed and a state immediately after the printing is finished. The state located on the left side of the figure shown by the line is the start end position, and the state located on the right side of the figure shown by the solid line is the end position. That is, in the printing apparatus 1 of the present embodiment, printing is performed once for one way from the start end position to the end position.

On the end position side of the casing 4, there is provided a separating dog 19 having a sloped part that is cut and raised obliquely upward with a part thereof facing the start end position, and a guide face that is continuous with the sloped face and extends along the printing direction.
Are formed. Also, on the side surface of the head holder 9,
Engagement for cooperating with the separating dog 19 to rotate the head holder 9 downward against elastic force when printing is completed and the carriage 8 moves toward the end position. Convex
20 are provided. The cam means is configured in this way.

When the head holder 9 is pushed down at the end position by the cam means, the claw portion 17a of the elastic tongue piece 17 is made to project completely from the lower surface 8c of the carriage 8, and from that state, the carriage 8 is moved to the start end position. When it is returned to the lower side, the claw portion 17a that once protrudes to the lower surface 8c side is inserted into the through hole 18 as described above.
The thermal head 7 is held in a state of being separated from the printing surface 7a because it is elastically engaged with the outer lower surface 8c.

On the starting end position side of the casing 4, there is provided a separation holding release dog 22 which is formed by cutting and raising a part of a side frame 21 extending in the vertical direction in the drawing at a substantially right angle toward the end position, and a carriage 22. When 8 is returned to the starting end position, the claw portion 17a hits against the protruding end of the separation holding release dog 22 and is pushed back, so that the engagement state with the lower surface 8c is released. Incidentally, the return of the carriage 8 to the starting end position is detected by, for example, the photoelectric type position sensor 24, and the rotation of the lead screw shaft 13 is stopped. In this way, the pressing spring 16
Since the head holder 9 is elastically pushed upward by the spring force of, the new card can be elastically held between the platen 3 and the thermal head 7 to perform printing.

At the start position, the thermal head 7 is located laterally with respect to the printing surface 2a of the card 2, and the carriage 8 is moved in the printing direction from the standby state so that the head end of the thermal head 7 is placed on the printing surface 2a of the card. The protrusion 20 to prevent the thermal head 7 from projecting due to the elastic biasing force.
A guide dog 23 for guiding through the guide frame 6 is formed by a part of the guide frame 6. When the convex portion 20 is detached from the guide dog 23 as the carriage 8 moves, the thermal head 7 can elastically hit the printing surface 2a of the card 2 in the printing state shown in FIG. Therefore, printing can be performed by the thermal head 7.

When replacing the thermal head 7 for maintenance or the like in the printing apparatus configured as described above,
As shown in FIG. 4, first, in order to remove the platen 3, the elastic piece 3b is bent in the direction of pulling out the boss portion 3c from the mounting hole 6a, and the engagement state between the boss portion 3c and the mounting hole 6a is changed. To release. Then, the platen 3 can be detached from the casing 4 by tilting the platen 3 in the direction of the arrow A and pulling it up.

When the platen 3 is removed, the head holder 9 is elastically urged by the pressing spring 16 and pivots in the projecting direction to some extent. Therefore, the head holder 9 is moved in the direction of the arrow B in the drawing, that is, the carriage 8 in this embodiment. It can be easily rotated so as to cause it to move at a substantially right angle to the moving direction of.
Further, since the rotation direction is a direction in which the opening portion 15a of the bearing portion 15 and the two-face width portion 14a of the shaft portion 14 can be inserted and removed, the head holder 9 is further rotated to form the opening portion 15a. Two
It is possible to easily align the surface width portion 14a with each other. In the aligned state, the head holder 9 is first slid to the left in the figure as shown by the arrow C in FIG. 5, whereby the fitted state between the bearing portion 15 and the shaft portion 14 can be released. Therefore, the head holder 9 can be easily removed from the carriage 8 by moving the head holder 9 upward in the drawing as shown by the arrow D after the movement in the direction of the arrow C. When the thermal head or the thermal head after the repair is attached, the procedure reverse to the above may be performed, and the attachment work can be easily performed.

As described above, in the printing state, the platen 3 can favorably restrict the rotation of the head holder 9 until it reaches the insertion / extraction position by the elastic force, and the head holder 9 does not come off. It should be noted that the prevention of the detachment of the head holder 9 is not limited to the platen 3, and, for example, the elastic tongue piece 17
May be extended so that the claw portion 17a is positioned below the lower surface 8c to some extent in the printed state. Since the platen 3 can be removed and the head holder 9 can be easily removed and installed by rotating the head holder 9 by a predetermined angle, the user himself / herself can perform replacement work without requesting repair from a specialized worker. You can Further, during the printing operation, the thermal head 7 is preferably positioned via the head holder 9 by the fitting state of the circular portion of the shaft portion 14 and the cylindrical inner peripheral surface portion of the bearing portion 15. It is not necessary to position the thermal head 7. As described above, since the thermal head 7 itself is not removed but the head holder 9 is removed, the thermal head 7 that requires positioning is previously positioned and fixed to the head holder 9, so that the thermal head 7 can be replaced during replacement work. It is possible to eliminate the trouble of positioning in the process. Further, in this embodiment, since the platen 3 can be easily removed as described above,
The cleaning work of the thermal head 7 can be easily performed.

[Effects of the Invention] As described above, according to the present invention, by removing the platen, the head support body is elastically rotated in a direction to reach the insertion / extraction position, so that the subsequent insertion / extraction position of the shaft support hole and the shaft portion. Can be quickly aligned, and the print head body can be released easily by rotating the print head body with respect to the carriage by a predetermined angle to release the fitting state between the shaft portion and the bearing portion. It can be detached, and it is possible to perform replacement work very easily with respect to what is fixed by screwing or adhesion. Therefore, it does not require advanced technology such as positioning when replacing the print head,
The user can easily perform the replacement work at the time of maintenance, the work cost at the time of replacement can be reduced, and a large loss of operating time can be prevented.

[Brief description of drawings]

FIG. 1 is a front view showing a main part of a printing apparatus according to the present invention. FIG. 2 is an exploded perspective view of a main part of the printer. FIG. 3 is a view corresponding to FIG. 1 showing the state at each position of the start end and the end of the print head body. 4 and 5 are views corresponding to FIG. 1 showing the procedure for removing the print head body. 1 ... printing device, 2 ... card, 2a ... printing surface, 3 ...
Platen, 3a ... Boss part, 3b ... Elastic piece, 3c ... Boss part, 4 ... Casing, 5 ... Card guide, 5a ... Mounting hole, 6 ... Guide frame, 6a ... Mounting hole, 7 …
… Thermal head, 8 …… Carriage, 8a ・ 8b …… Wall, 8c …… Lower surface, 9 …… Head holder, 9a …… Arm, 10 …… Arm, 11 …… Linear shaft, 12 …… Screw Pin, 13 ...... Lead screw shaft, 14 ...... Boss part, 14a ...... Width width part, 15 ...... Bearing part, 15a ...... Opening part,
16 …… Pressing spring, 17 …… Elastic tongue, 17a …… Claw, 18
...... Through hole, 19 ...... Separation dog, 20 ...... Convex part, 21 ...... Side frame, 22 ...... Separation holding release dog, 23 ...... Guide dog, 24 ...... Position sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41J 3/20 109 C

Claims (1)

[Scope of utility model registration request] 1. A print head body is rotatably supported by a carriage supported by a casing so as to be capable of reciprocating along a platen so as to move toward and away from the platen, and the print head body is springed in a printing state. A structure for mounting a print head body that is elastically pressed against the platen by a C-shaped shaft support hole provided in either one of the carriage and the print head body, and the C-shaped shaft support hole. Partial circular cross-section provided on the other of the carriage and the print head body so that it can be inserted into and removed from the shaft support hole in the radial direction through the opening and can be rotatably fitted The print head body is provided with a shaft portion, and the insertion / removable position of the shaft support hole and the shaft portion is rotated by the elastic urging force of the spring when the platen is removed from the printing state. A structure for mounting a print head body, which is provided on the rotation direction side of the.