JP3507644B2 - Line type thermal head support structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for a line type thermal head in which a head block to which a line type thermal head is mounted is swingably supported by a support shaft. About. 2. Description of the Related Art Conventionally, in a printer using a line type thermal head, it is necessary to uniformly press the entire printing surface of the line type thermal head against a platen. In order to achieve such uniform pressure contact with a simple structure, a line type thermal head support structure as shown in FIG. 3 is employed. First, a line type thermal head 1 is detachably attached to a head block 2, and a head fulcrum pin 3 extending in a direction orthogonal to the printing width direction of the line type thermal head 1 is fixed to the head block 2. The head fulcrum pin 3 is provided at the center of gravity of the line type thermal head 1 in the print width direction in the head block 2 to which the line type thermal head 1 is attached. A frame 4 is provided on the upper side of the printer so as to be vertically movable, and a head mounting plate 5 is fixed to the frame 4. A fitting recess 6 opened upward is formed in the head mounting plate 5, and the head fulcrum pin 3 is rotatably fitted in the fitting recess 6.
Further, one end of a leaf spring 7 is fixed to the frame 4, and the other end of the leaf spring 7 presses the head fulcrum pin 3 fitted in the fitting recess 6 in a fitting direction (downward). I have. When mounting the line type thermal head 1 to the printer, the head fulcrum pin 3 of the head block 2 on which the line type thermal head 1 is mounted is engaged with the fitting recess 6 and is engaged with the fitting recess 6. This is performed by pressing the head fulcrum pin 3 with a leaf spring 7. In this state, when the printing surface of the line type thermal head 1 was brought into contact with the platen 8 by moving the frame 4 downward, the head fulcrum pin 3 was slightly lifted from the bottom of the fitting recess 6 to form a gap 9. In this state, the printing surface of the line type thermal head 1 is pressed against the platen 8 by the pressing force of the leaf spring 7. Since the head fulcrum pin 3 pressed by the leaf spring 7 is rotatable in the fitting concave portion 6, when the printing surface of the line type thermal head 1 is pressed against the platen 8, the printing of the line type thermal head 1 is performed. The head block 2 swings about the head fulcrum pin 3 so that the surface is uniformly pressed against the platen 8. In this printer, when setting the paper and the ink ribbon, the frame 4, the head mounting plate 5, the head block 2, and the line-type thermal head 1 are integrally moved up by a head-up mechanism. The printing surface is separated from the platen 8. When the print surface of the line type thermal head 1 is separated from the platen 8 by raising the head block 2 or the like to set a sheet or an ink ribbon, the head block 2 Swings around the head fulcrum pin 3, and one end of the line type thermal head 1 may remain in contact with the platen 8. Then, it takes time to set the paper and the ink ribbon. If the head block or the like is largely moved upward when the head is raised, it is possible to prevent one end of the line type thermal head 1 from contacting the platen 8 at the time of head up. Therefore, it is difficult to reduce the size of the printer. Accordingly, the present invention prevents the line type thermal head from swinging and one end of the line type thermal head from coming into contact with the platen when the print surface of the line type thermal head is separated from the platen by raising the head block or the like. It is an object of the present invention to provide a support structure of a line type thermal head which can be used. Means for Solving the Problems The invention according to claim 1 is:
A support block extending in a direction orthogonal to the print width direction of the line type thermal head is provided on a head block to which the line type thermal head is attached, and the support shaft is fitted in an upper open fitting recess formed in a support member of the printer. In a line type thermal head support structure rotatably supported and swingably supporting the head block to which the line type thermal head is attached, the head block sandwiching a center line of the support shaft Provided in the support member is a swing prevention member facing the upper edge of both sides of the both sides of the predetermined distance.
At least one of the swing preventing members is provided so as to be movable in a direction of coming into contact with and separating from the upper edge of the head block, and the support shaft fitted to the fitting recess is fitted to the two swing preventing members. a pressing member for pressing the engagement direction is provided, the one rocking
When the movement preventing member is brought close to the upper edge portion of the head block, the support shaft is pressed by the pressing member to press the printing surface of the line type thermal head against the platen. The swing prevention member regulates the swing operation of the head block, and prevents the one swing.
When the member is moved away from the upper edge of the head block, Yuradobo upper edge of the head block of the one
The support shaft can be removed from the fitting recess without interfering with the stop member . Therefore, when the head block is moved up and the printing surface of the line type thermal head is separated from the platen in order to set the paper and the ink ribbon, when the head block moves so as to swing around the support shaft, the head is moved. The upper edge of the block abuts against the anti-swing member to restrict the oscillating operation, and when the head is raised, the head block oscillates around the support shaft to prevent one end of the line type thermal head from contacting the platen. You. In addition, since at least one of the swing prevention members is movable in the direction of coming into contact with and separating from the upper edge of the head block, by moving the swing prevention member in the direction away from the upper edge of the head block, The support shaft can be removed from the fitting recess. [0010] Here, the upward opening means that the line type thermal head is opened in a direction away from the platen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The same parts as those described in FIG. 3 are denoted by the same reference numerals. The line type thermal head 1 is detachably attached to a head block 2, and a head fulcrum pin 3 which is a support shaft extending in a direction orthogonal to the print width direction of the line type thermal head 1 is fixed to the head block 2. I have. The head fulcrum pin 3 is formed at the center of gravity of the line type thermal head 1 in the print width direction in the head block 2 to which the line type thermal head 1 is attached. A frame 4 as a support member is provided on the upper side of the printer so as to be movable in the vertical direction, and a head mounting plate 5 as a support member is fixed to the frame 4. The head mounting plate 5 is formed with a fitting recess 6 into which the head fulcrum pin 3 is rotatably fitted and opened upward (in a direction in which the line-type thermal head 1 is separated from the platen 8). . Further, the head mounting plate 5 has one end side in the longitudinal direction (the printing width direction of the line type thermal head 1) of the head block 2 in which the head fulcrum pin 3 is fitted in the fitting concave portion 6. A leaf spring mounting piece 10, which is a swing prevention member bent to a position facing the upper edge, is formed. The leaf spring mounting piece 10 includes the fitting recess 6.
One end of a leaf spring 11, which is a pressing member that presses the head fulcrum pin 3 fitted in the fitting direction in the fitting direction, is fixedly held. A leaf spring mounting plate 12, which holds the other end of the leaf spring 11 and also serves as an anti-swing member, is disposed at a position facing the upper edge of the other end of the head block 2. The attachment plate 12 is attached to the frame 4 by an attachment screw 13 so as to be vertically movable. When the mounting screw 13 is tightened to move the leaf spring mounting plate 12 to the lowest position, the pressing force of the leaf spring 11 acting on the head fulcrum pin 3 becomes maximum. The leaf spring mounting piece 10 and the leaf spring mounting plate 12 are located at the same distance from the fitting recess 6. Further, when the mounting screw 13 is tightened to move the leaf spring mounting plate 12 to the lowest position, the lower end of the leaf spring mounting piece 10 with respect to the upper edge of the head block 2 and the lower end of the leaf spring mounting plate 12 The dimensions between them are set to be substantially the same. FIG. 1 shows a state in which the head fulcrum pin 3 fitted in the fitting recess 6 is pressed by the leaf spring 11 and the printing surface of the line type thermal head 1 is pressed against the platen 8. It is. The leaf spring mounting plate 12 is fixed at the lowest position by tightening the mounting screw 13. Since the head fulcrum pin 3 pressed by the leaf spring 11 is rotatable in the fitting concave portion 6, when the printing surface of the line type thermal head 1 is pressed against the platen 8, the printing of the line type thermal head 1 is performed. The head block 2 swings about the head fulcrum pin 3 so that the surface is uniformly pressed against the platen 8. When a sheet or ink ribbon is set between the printing surface of the line type thermal head 1 and the platen 8, the frame 4 and the head are moved from the state shown in FIG. 1 by a head-up mechanism (not shown). The mounting plate 5, the head block 2, and the line type thermal head 1 are integrally headed up, and the printing surface of the line type thermal head 1 is separated from the platen 8. When the head block 2 moves so as to swing around the head fulcrum pin 3 during the head-up, the upper edge of the head block 2 is
0, or the lower end of the leaf spring mounting plate 12 to restrict the swinging operation. Therefore, it is possible to reliably prevent the head block 2 from swinging around the head fulcrum pin 3 and the end of the line type thermal head 1 from coming into contact with the platen 8 when the head is raised. For this reason, a gap is secured between the printing surface of the line type thermal head 1 and the platen, and paper and ink ribbon can be easily set. FIG. 2 shows a state in which the head block 2 is removed from the head mounting plate 5 by removing the head fulcrum pin 3 from the fitting recess 6 for maintenance or replacement of the line type thermal head 1. The leaf spring mounting plate 12 is moved upward by loosening the mounting screw 14. Thereby, the lower end of the head mounting plate 5 and the head block 2
When the head fulcrum pin 3 is removed from the fitting recess 6, the head block 2
The upper edge portion can be easily removed without interfering with the head mounting plate 5. Further, by moving the leaf spring mounting plate 12 upward, the other end of the leaf spring 11 attached to the leaf spring mounting plate 12 moves upward, and the head fulcrum pin 3
, The pressing force of the leaf spring 11 acting on the plate becomes small. Therefore,
The head fulcrum pin 3 can be easily removed from the fitting concave portion 6 with a small force, and the maintenance and replacement workability of the line type thermal head 1 is improved. According to the first aspect of the present invention, when the print block of the line type thermal head is separated from the platen by raising the head block to set the paper and the ink ribbon, When the upper edge of the block abuts against the anti-swing member, the head block can be prevented from swinging around the support shaft. Therefore, when the head is raised, the head block swings around the support shaft and the line is moved. It is possible to prevent one end of the thermal head from coming into contact with the platen. Therefore, when the head is raised, a gap is secured between the printing surface of the line thermal head 1 and the platen, so that paper and ink ribbon can be easily set. And at least one of the swing prevention members is movable in the direction of coming into contact with and separating from the upper edge of the head block. By moving the anti-swing member in the direction away from the upper edge of the head block, the support shaft can be easily removed from the fitting recess.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing a support structure of a line type thermal head according to an embodiment of the present invention. FIG. 2 is a front view showing a state when a head fulcrum pin is removed from a fitting recess. FIG. 3 is a front view showing a support structure of a conventional line type thermal head. [Description of Signs] 1 Line type thermal head 2 Head block 3 Support shafts 4, 5 Support member 6 Fitting recesses 10, 12 Swing prevention member 11 Pressing member

Claims (1)

(57) [Claim 1] A support block extending in a direction orthogonal to a printing width direction of the line type thermal head is provided on a head block to which the line type thermal head is attached, and a support member of the printer is provided. A support structure for a line-type thermal head, wherein the support shaft is rotatably supported by a fitting concave portion which is formed in an upper opening and the head block to which the line-type thermal head is mounted is swingably supported. An anti-swing member provided on the upper edge of both sides of the head block with the center line of the support shaft interposed therebetween with a predetermined distance therebetween, and at least one of the anti-swing members is provided on the head. A pressing member is provided so as to be movable in the direction of coming into contact with and separating from the upper edge portion of the block, and the two anti-swing members have a pressing member that presses the support shaft fitted in the fitting recess in the fitting direction. Only, when the rocking motion preventing member of the one is brought close to the upper edge of the head block, and presses the support shaft in the pressing member is pressed against the printing surface of the line type thermal head to the platen, At the time of head-up, when the two swing prevention members regulate the swing operation of the head block, and when one of the swing prevention members is separated from the upper edge of the head block, A support structure for a line-type thermal head, wherein the support shaft can be removed from the fitting recess without an upper edge portion interfering with the one swing prevention member .