JP3824303B2 - Line thermal printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a line thermal printer having a structure in which a line thermal head is supported by a head unit, and the head unit is swingably supported via a hinge portion.
[0002]
[Prior art]
In general, in a line thermal printer, a hinge is provided at one end of the head unit so that the ink ribbon can be easily attached to the head unit and the paper can be attached to the paper transport path. A configuration that can swing is adopted. The head unit swings between the print position on the paper transport path with the hinge portion as a center and the retreat position in which the head unit is turned upside down by approximately 90 ° from the position.
[0003]
Now, if the head unit in an inverted state at this retracted position naturally swings toward the printing position without any support, it will be accelerated by its own weight and vigorously move to the platen provided at the printing position. There is a risk of colliding and damaging the platen and thermal head.
For this reason, conventionally, a fluid damper device has been incorporated to suppress the swinging motion of the head unit. Since the fluid damper has a frictional resistance proportional to the speed, a situation where the head unit collides with the platen vigorously is avoided.
[0004]
[Problems to be solved by the invention]
However, the fluid damper not only acts as a resistance only when the head unit swings (i.e., tilts) toward the printing position, but also resists the head unit when lifting the head unit from the printing position to the retracted position. Will act as. Accordingly, the work of lifting the head unit to the retracted position requires handling of heavy objects, but has the disadvantage that workability is reduced.
[0005]
Furthermore, the head unit is locked at the printing position by a locking member. When the locked state is released, a so-called pop-up spring is preferably used so that the head unit immediately leaves the printing position. . However, in the case of the structure using the fluid damper described above, the operation of the pop-up spring is suppressed by the resistance force of the fluid damper, so that the spring does not function well and the operability is deteriorated.
[0006]
There is also known a structure having a structure in which a head unit is lifted by a spring member from a printing position to a retracted position instead of a fluid damper. However, in this structure, since the swing operation from the retracted position to the print position must be performed against the spring force, a large amount of labor is required for this operation. In addition, the spring member that simply lifts the head unit from the printing position to the retracted position is large and requires a long stroke, leading to an increase in the size of the apparatus.
[0007]
The present invention has been made in view of such circumstances, and prevents the head unit from falling down vigorously due to its own weight, so that the head unit can be easily swung in either direction, The purpose is to provide a line thermal printer with excellent safety and operability.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has a head unit that supports a line thermal head, and this head unit is connected to the printer main body by a hinge portion provided between the head unit and the plate thermal head. In a line thermal printer that can swing between a close print position and a retracted position separated from the platen,
The hinge portion has a unidirectional torque control mechanism, and this unidirectional torque control mechanism is a constant load torque that does not depend on the swing speed when the head unit swings from the retracted position to the print position. When the load direction load torque is applied to the head unit and the head unit swings from the printing position to the retracted position, the head unit can swing at least with an unload direction load torque that is smaller than the load direction load torque. (Claim 1).
[0009]
The present invention having such a configuration prevents the head unit from falling down vigorously by its own weight with the load torque in the load direction of the unidirectional torque control mechanism when the head unit is swung from the retracted position to the printing position. Can be done. Also, when swinging from the print position to the retracted position, the unidirectional torque control mechanism can swing the head unit with an unload direction load torque smaller than the load direction load torque. Without lifting the head unit.
[0010]
Here, the load direction load torque is preferably set to a magnitude that can support the weight of the head arm (claim 2). By setting the load direction load torque in this way, the reaction force received from the unidirectional torque control mechanism when the head unit is swung from the retracted position to the print position is reduced. Can also be reduced.
[0011]
The unload direction load torque is preferably set to a value close to zero (claim 3). By setting the unload direction load torque in this way, the load when swinging the head unit from the printing position to the retracted position (that is, lifting) is only the weight of the head unit, and the burden on the swinging operation. Can be further reduced.
[0012]
Further, a head locking member that locks the head unit at the printing position, and a head pop-up spring that lifts the head unit to a position that is not locked by the locking member when the locking by the head locking member is released. It can also be set as the structure provided (Claim 4).
[0013]
Since the present invention uses the unidirectional torque control mechanism of a small unload direction load torque, the function of the head mop-up spring is sufficiently exhibited. Therefore, the operability when the locked state of the head locking member is released can be improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments in which the present invention is applied to a line thermal printer will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an outline of a line thermal printer according to an embodiment of the present invention.
As shown in FIG. 1, the line thermal printer uses ink on the ink ribbon 3 melted by the thermal head 620 while holding the roll paper 2 drawn out along the paper transport path 1 between the platen 31 and the thermal head 620. Is transferred onto the surface of the roll paper 2. In addition, a lower sensor unit 40 and an upper sensor unit 50 are disposed on the paper transport path 1 in order to detect the position of the label or tag attached to the mount with respect to the so-called label paper or tag paper. Has been.
[0015]
2-7 is a figure which shows the whole structure of the line thermal printer which concerns on this embodiment, Among these, FIG. 2 is a perspective view which shows the external appearance of a line thermal printer. As shown in FIG. 2, the line thermal printer has an appearance in which an upper portion of a main body case 10 is covered with a top cover 11 that can be freely opened and closed. An operation panel 13 for setting is provided.
[0016]
FIG. 3 is a perspective view showing the internal structure of the line thermal printer.
A main body frame 14 for supporting each component is provided on the inner surface of the main body case 10. The main body frame 14 includes a control box 15, a roll paper supply unit 20, a front unit 30 including a platen 31, and a lower unit. Each component of the side sensor unit 40, the upper sensor unit 50, the head unit 60, and the ribbon mounting unit 70 is incorporated.
[0017]
Here, in order to understand the overall structure of the line thermal printer, the setting procedure of the roll paper 2 and the ink ribbon 3 will be described with reference to FIGS.
First, as shown in FIG. 4, the roll paper 2 is mounted on the roll paper supply unit 20, and the paper 2 a pulled out from the roll paper 2 is placed on the upper surface of the front unit 30 including the lower sensor unit 40 and the platen 31. Deploy.
[0018]
Next, the upper sensor unit 50 is tilted in the direction indicated by the arrow a in FIG. 4, and the upper sensor unit 50 is disposed on the upper surface of the sheet 2a as shown in FIG. By this operation, the upper sensor unit 50 is disposed at a position facing the lower sensor unit 40 via the paper 2a.
[0019]
Subsequently, the head unit 60 is tilted in the direction indicated by the arrow b in FIG. 5, and the head unit 60 is disposed on the upper surface of the sheet 2a as shown in FIG. By this operation, the head unit 60 is disposed at a position facing the platen 31 via the paper 2a.
[0020]
Further, the roll-shaped ink ribbon 3 is mounted on the ribbon mounting unit 70 in the inverted state shown in FIG. By these operations, the roll paper 2 and the ink ribbon 3 are set as shown in FIG. Thereafter, when the top cover 11 is closed, the use state of the appearance shown in FIG. 2 is formed.
[0021]
Next, each component will be described in more detail.
The control box 15 shown in FIG. 3 includes a control circuit for controlling the operation of the line thermal printer, an interface circuit for processing a data signal sent from a connected device such as a computer, and setting information input from the operation panel 13. The memory etc. which memorize | store are incorporated.
[0022]
As shown in FIG. 3, the roll paper supply unit 20 is incorporated in the inner rear portion of the main body case 10, and includes a support plate 210, a roll shaft 220, a left roll guide 230, and a right roll guide 240.
The support plate 210 is a part of the main body frame 14, and a roll support portion 211 made of a semicircular recess is formed at the center of the upper end of the support plate 210. As shown in FIG. 8, the roll shaft 220 is a metal rod-like body. The roll shaft 220 is inserted into the central hole of the roll paper 2 and both ends thereof are placed on the roll support portion 211, thereby The paper 2 is supported rotatably.
[0023]
Bearings (slide bearings) 221 are provided at both ends of the roll shaft 220 and in contact with the roll support portion 211, and the rotational resistance when the roll paper 2 is fed by the relative rotation of the bearing 221. This makes it possible to smoothly feed out the roll paper 2.
[0024]
In addition, a pair of disk-shaped holder disks 222 are detachably attached to an intermediate portion of the roll shaft 220. The holder disk 222 can be selected to have an appropriate outer diameter in accordance with the inner diameter of the central hole of the roll paper 2. By mounting the holder disk 222 on the roll shaft 220, the roll shaft 220 can be positioned on the central axis of the roll paper 2 and the roll paper 2 can be fed out without any deviation. Further, by adjusting the fixing position of the holder disk 222 with respect to various roll papers 2 having different widths, the holder disk 222 can be inserted into the center hole of the roll paper 2 and the inner surface thereof can be supported. The holder disk 222 is fixed to the roll shaft 220 with a fastener 223 such as a screw.
[0025]
The left roll guide 230 and the right roll guide 240 are made of a metal plate, and are disposed inside the support plate 210 as shown in the plan view of FIG. Each of the roll guides 230 and 240 is movable along the bar-shaped guide rail 250 fixed between the left and right support plates 210 in the axial direction of the roll shaft 220, that is, in the width direction of the supported roll paper 2. ing. Each of these roll guides 230 and 240 is a component for guiding both end surfaces of the roll paper 2 supported by the roll shaft 220. In addition, in order to avoid interference with the roll shaft 220, concave portions 231 and 241 are formed at the center of the upper ends of the roll guides 230 and 240, respectively.
[0026]
A left guide rack 232 extending inward in the width direction of the supported roll paper 2 is attached to the lower end of the left roll guide 230, while the width direction of the roll paper 2 supported also at the lower end of the right roll guide 240. A right guide rack 242 extending inward is mounted. A pinion gear 251 is disposed on the bottom surface of the main body frame 14, and the guide racks 232 and 242 mesh with the pinion gear 251 symmetrically about the pinion gear 251. If one roll guide 230 or 240 is moved in the width direction by this mechanism, the other roll guide 240 or 230 is also moved by the same amount in the opposite direction in conjunction with it. Further, the positions of the roll guides 230 and 240 are adjusted so as to approach or separate from each other on the basis of the substantially central position between the left and right support plates 210.
[0027]
Since the roll guides 230 and 240 can be accurately and easily adjusted with reference to the approximate center position between the left and right support plates 210 with the above-described configuration, various roll papers 2 having different widths are mounted. However, the roll paper 2 can always be held at the center position of the support plate 210 by guiding both end faces of the roll paper 2.
[0028]
One roll guide (right roll guide 240 in the figure) has a fixed operation portion 243 formed at the upper corner. A screw hole is formed in the fixing operation portion 243, and as shown in a side view of FIG. 10, a fixing member 244 constituted by a long screw penetrates and is screwed into the screw hole. An abutting portion 244 a that contacts and separates from the peripheral surface of the guide rail 250 is formed at the tip of the fixing member 244, and when the abutting portion 244 a is pressed against the peripheral surface of the guide rail 250 by rotating the fixing member 244. The free movement of the right roll guide 240 is restricted. Since the right roll guide 240 and the left roll guide 230 are interlocked via the guide racks 232 and 242 and the pinion gear 251 as described above, when the movement of one roll guide 240 is restricted, the other roll guide 230 is simultaneously controlled. Movement is also restricted. Thereby, each roll guide 230,240 can be fixed.
[0029]
Returning to FIG. 3, the front unit 30 is provided at an inner front portion of the main body case 10, that is, at a rear position of the paper discharge port 12. The platen 31 is rotatably incorporated in the front unit 30. As is well known, the platen 31 is a member provided with an elastic material such as synthetic rubber around the rotation shaft, and has a function of supporting the back surface of the paper during the printing operation and conveying the paper as it rotates. ing. Further, the front unit 30 is provided with a sharp paper cutting plate 32 called a tear bar, and cuts the printed paper 2 a in cooperation with a cutter (not shown) provided in the head unit 60.
[0030]
The lower sensor unit 40 includes a lower case 41 and a lower guide 42 as shown in the plan view of FIG. 11 and the sectional side view of FIG. The lower guide 42 is disposed at a rear position of the front unit 30, and includes two rod-shaped lower guide shafts 43 and a lower guide plate 44. Of these, the lower guide plate 44 is a part of the main body frame 14. The lower guide plate 44 has a concave shape as shown in FIG. 12, and a lower guide shaft 43 is provided along the opening. Both the lower guide plate 44 and the lower guide shaft 43 extend in the width direction of the main body case 10.
[0031]
In the lower case 41, a light emitting element 45 and a first light receiving element 46 are incorporated side by side at the center. Further, as shown in FIG. 12, a concave portion 41a that engages with the lower guide shaft 43 is formed at both ends of the lower case 41, and further, the lower guide plate 44 has a lower surface from the lower surface of the concave portion 41a. A leg portion 41b that contacts the bottom surface extends.
[0032]
Further, an elastic member 47 made of, for example, urethane resin is filled between the concave portion 41a of the lower case 41 and the lower guide shaft 43. The length of the leg 41b is adjusted so as to maintain the elastic member 47 in a properly compressed state. With this configuration, the lower case 41 can be easily moved and adjusted along the lower guide shaft 43, and the frictional force between the appropriately compressed elastic member 47 and the lower guide shaft 43 is used to adjust the position of the lower case 41. After adjustment, it can be held in place. As shown in FIG. 11, a scale 48 is displayed in the width direction on the lower guide plate 44. By using this scale 48 as a guide, the positioning of the lower case 41 becomes easier.
[0033]
As shown in FIG. 13, the upper sensor unit 50 includes an upper case 51 and an upper guide plate 52. As shown in FIGS. 3 and 4, one end of the upper guide plate 52 is attached to one side surface of the main body frame 14 via a hinge portion 53, and is rotatable about the hinge portion 53. . Further, a locking portion (not shown) is formed at the other end, and this locking portion engages with a lock lever (not shown) provided on the other side surface of the main body frame 14, and FIG. The setting state shown is maintained. In this setting state, the upper guide plate 52 and the lower guide 42 are disposed to face each other via the paper 2a. As shown in FIG. 13, a guide hole 54 extending in the width direction is formed at the center of the upper guide plate 52.
[0034]
As shown in FIG. 12, the upper case 51 has a second light receiving element 55 incorporated in the center thereof. Further, the support case 56 is formed on the lower surface of the upper case 51 so as to extend to both sides with a certain interval. These support pieces 56 are arranged on the lower surface side of the plate 52 through guide holes 54 formed in the upper guide plate 52, and the upper guide plate 52 is sandwiched between the support piece 56 and the lower surface of the upper case 51. Yes. Further, an elastic member made of a leaf spring 57 is mounted on the lower surface of the upper case 51 so as to face the support piece 56, and the upper guide plate 52 is clamped in cooperation with the support piece 56 with the spring force. ing.
[0035]
With this configuration, the position of the upper case 51 can be easily adjusted along the guide hole 54 of the upper guide plate 52, and the position of the upper case 51 can be adjusted with the clamping force between the leaf spring 57 and the support piece 56. Can be held in place. The upper guide plate 52 also has a scale 58 similar to that of the lower guide plate 44. By using the scale 58 as a guide, the positioning of the upper case 51 becomes easier.
[0036]
For each of the sensor units 40 and 50 described above, the supplied paper is classified into label paper and tag paper, for example, as follows.
In other words, the label paper is affixed to a long mount wound in a roll shape with a predetermined interval, but when this type of label paper is to be printed, The incorporated light emitting element 45 and the second light receiving element 55 incorporated in the upper case 51 are arranged to face each other. The label paper passing between the elements 45 and 55 is irradiated with light from the light emitting element 45, and the amount of light transmitted through the label paper is detected by the second light receiving element 55.
[0037]
At this time, since the amount of light transmitted only through the mount differs from the amount of light transmitted through both the mount and the label, the leading or trailing end of the label is recognized by detecting this change in the amount of transmitted light. Is done.
[0038]
On the other hand, a mark indicating the interval between the tags is displayed on the tag sheet. The display portion of this mark and the surface not displayed are different in light reflectance. When this type of tag paper is to be printed, the mark is detected using the light emitting element 45 and the first light receiving element 46 incorporated in the lower case 41. That is, light is emitted from the light emitting element 45 toward the tag sheet, and reflected light from the tag sheet is detected by the first light receiving element 46.
[0039]
At this time, since the amount of light reflected on the surface where the mark is not displayed is different from the amount of light reflected on the display portion of the mark, the leading edge or the trailing edge of the label is detected by detecting the change in the amount of reflected light. Is recognized.
[0040]
Next, the head unit 60 includes a head support frame 610 and a thermal head 620 (line thermal head) as shown in the exploded perspective view of FIG. The head support frame 610 is formed in a box shape with an open bottom. On the other hand, the thermal head 620 has a line-shaped heating element 622 mounted on the lower surface of the head support plate 621. As shown in the sectional side view of FIG. 15, the thermal head 620 has the head support plate 621 incorporated inside the head support frame 610 with the heating element 622 exposed from the bottom opening of the head support frame 610.
[0041]
That is, as shown in FIG. 14, bearing portions 623 are formed at the center portions of the front end and the rear end of the head support plate 621, and rod-shaped lever engaging pins 624 pass through these bearing portions 623. The support is fixed. Further, hooks 625 protruding forward are formed near both sides of the front end of the head support plate 621. The hook 625 has a narrow arm portion 625a from the base end to the middle portion, and the distal end portion forms a wide locking portion 625b.
[0042]
On the other hand, in the head support frame 610, a long hole 611 is formed at substantially the center of the front and back surfaces, and a stepped notch 612 is formed near both sides of the front surface. The end portions of the lever engaging pin 624 are inserted through the long holes 611, respectively. Further, the notch 612 has a width wider than the locking portion 625b of the hook 625 formed on the head support plate 621 on the upper side of the step portion, and is narrower than the locking portion 625b of the hook 625 on the lower side of the step portion. And it is formed in the width | variety which can insert the arm part 625a. A hook 625 is fitted and locked to the head support plate 621 in the notch 625.
[0043]
As described above, the thermal head 620 has a head support frame that does not require a fastener such as a screw due to the engagement between the lever engagement pin 624 and each elongated hole 611 and the engagement between the hook 625 and the notch 625. Since it can be incorporated into 610, the assembling work can be easily performed, and the maintainability is good. In addition, the incorporated thermal head 620 can move with respect to the head support frame 610 by the gap between the long hole 611 and the notch 612.
[0044]
Further, as shown in FIG. 15, a thermal head pressing unit 630 is mounted on the inner ceiling surface of the head support frame 610 so as to avoid interference with the lever engaging pin 624, and the thermal head 620 is attached by the unit 630. The platen 31 is elastically pressed and biased toward the platen 31 (that is, downward).
[0045]
As shown in FIGS. 16A and 16B, the thermal head pressing unit 630 includes a displacement regulating member including an upper case 631 and a lower case 632. The upper case 631 has an opening at the bottom and a plurality of long holes 633 formed at regular intervals on the side surface. A plurality of protrusions 634 are provided at regular intervals on the inner ceiling surface of the upper case 631. The upper surface of the upper case 631 is fixed to the inner ceiling surface of the head support frame 610 by a fastener 635 such as a screw.
[0046]
The lower case 632 has an opening at the top, and a plurality of engagement protrusions 636 are formed on the upper edge of the upper case at a predetermined interval. A plurality of protrusions 637 are also provided on the inner bottom surface of the lower case 632 at regular intervals. The upper and lower cases 631 and 632 are slidably fitted to the upper case 631 so that the engaging protrusions 626 are engaged with the elongated holes 633 of the upper case 631. In this fitted state, the protrusions 634 and 637 formed on the cases 631 and 632 are opposed to each other, and the compression coil springs 638 (elastic members) are supported by the protrusions 634 and 637 in the state where both ends are supported. , 632 inside.
[0047]
Here, the slidable contact surface between the lower case 632 and the upper case 631 functions as a slide guide portion that restricts relative displacement in a direction (lateral direction) orthogonal to the urging direction of the compression coil spring 638. Further, the engaging protrusion 636 and the long hole 633 are stoppers that restrict the downward relative displacement (that is, restrict the expansion of the compression coil spring 638) when the engaging protrusion 636 contacts the inner bottom surface of the long hole 633. It functions as an engaging part.
[0048]
The thermal head pressing unit 630 having such a configuration does not cause the compression coil spring 638 to scatter even when the thermal head 620 is detached from the head support frame 610, and when the thermal head 620 is incorporated into the head support frame 610. In addition, there is no possibility that the compression coil spring 638 is buckled. Therefore, it is possible to more easily perform the incorporation or disassembly work.
[0049]
FIG. 17 is a perspective view showing the configuration of the back surface portion of the head unit 60 described above.
On the back surface of the head support frame 610, as shown in the figure, an operation lever 640 is mounted that is disposed horizontally and is rotatable about a support shaft 641.
The operation lever 640 is engaged with the rear end portion of the lever engagement pin 624 described above. Although not clearly shown in the drawing, a long hole 643 extending in the rotation direction is formed in the middle portion of the operation lever 640, and a fastener 644 such as a screw is supported by the long hole 643 on the head support. It is attached to the back of the frame 610. By loosening the fastener 644, the operation lever 640 can rotate within the length range of the long hole 643. On the other hand, when the fastener 644 is tightened, the operation lever 640 is pressed against the head support frame 610 and rotated. Be regulated. Further, a scale 645 is provided near the tip of the operation lever 640, and the tip of the operation lever 640 functions as a pointer for the scale 645.
[0050]
When the fastener 644 is loosened and the operating lever 640 is rotated with the scale 645 as a guide, the lever engaging pin 624 is also rotated integrally, and the thermal head 620 swings around the hook 625 shown in FIG. . By this swing, the relative position between the heating element 622 of the thermal head 620 and the platen 31 can be adjusted.
[0051]
The relative position is preferably adjusted according to the thickness of the supplied paper. In general, when label paper, tag paper, or the like is to be printed, the operation lever 640 is rotated downward to lower the rear side of the thermal head 620. Conversely, when thin paper is to be printed, the operation lever 640 may be rotated upward to lift the rear side of the thermal head 620. Thereby, the position of the thermal head 620 facing the platen 31 is finely adjusted. Further, even when the center position of the heating element 622 provided in the thermal head 620 is deviated from the contact point with the platen 31 due to a manufacturing error or the like, The position of the heating element 622 with respect to the platen 31 can be adjusted.
[0052]
As shown in FIG. 5, the head unit 60 described above has one end attached to the main body frame 14 via a hinge portion 650, and a print position closely contacting the platen 31 around the hinge portion 650. Rotation is possible between a retracted position separated from the platen 31. As a result, when the paper is loaded or when the ribbon is loaded, the paper transport path 1 and the lower surface of the thermal head 620 can be opened to easily load the paper and the ribbon.
[0053]
18A and 18B are diagrams showing the configuration of the hinge portion, where FIG. 18A is a front view in an open state, and FIG. 18B is a side view in a closed state.
The hinge portion 650 is provided with a unidirectional torque control mechanism 651, and one end portion of the head unit 60 and the main body frame 14 are rotatably connected via the mechanism 651. The unidirectional torque control mechanism 651 includes a mechanism main body 652 incorporating a component for torque control, and a support shaft 653 extending from the mechanism main body 652, and one end of the head unit 60 is attached to the mechanism main body 652. It is fixed. A support shaft 653 extending from the mechanism main body 652 is fixed to the main body frame 14.
[0054]
The support shaft 653 is disposed in parallel with the paper transport direction in the printing unit, and the head unit 60 is rotatable along a virtual plane orthogonal to the support shaft 653.
[0055]
Here, the unidirectional torque control mechanism 651 is a hinge mechanism that functions as a one-way clutch and a torque limiter. When the head unit 60 rotates from the retracted position to the print position, it is supported inside the mechanism main body 652. The shaft 653 generates a load direction load torque that is a constant load torque that does not depend on the rotation speed. The load direction load torque generated at this time is set to a magnitude that can support the weight of the head unit 60. Therefore, when the head unit 60 is rotated from the retracted position to the printing position, it is possible to prevent the head unit 60 from falling down vigorously due to its own weight and colliding with the platen 31.
[0056]
Further, when the head unit 60 rotates from the printing position to the retracted position, the unidirectional torque control mechanism 651 is in the unload direction, which is a load torque smaller than the load direction load torque with respect to the support shaft 653 inside the mechanism body 652. It has a structure that generates load torque. It is preferable that the unload direction load torque generated at this time is a value substantially close to zero. By setting in this way, the load when the head unit 60 is rotated from the printing position to the retracted position (that is, lifted) is only the weight of the head unit 60, and the burden on the rotation work is reduced. Can do.
[0057]
Further, a head pop-up spring 654 composed of a compression coil spring is provided in the vicinity of the hinge portion 650 in the main body frame 14, while the head unit 60 has a spring that presses the head pop-up spring 654 at the printing position. A receiving portion 655 is formed. The bed pop-up spring 654 is compressed by the spring receiving portion 655 when the head unit 60 is in the printing position (FIG. 18B).
[0058]
Further, as shown in the side view of FIG. 19, the other end of the main body frame 14 in the width direction (the opposite side of the hinge portion 650) is used to lock the other end of the head unit 60 and fix it at the printing position. A head locking member 660 is provided, and an engaging pin 613 that is locked to the head locking member 660 protrudes from the other end of the head unit 60. That is, the head unit 60 that has been rotated to the printing position is prevented from rotating in the retracted position direction by the engagement pin 613 being locked to the head locking member 660.
[0059]
The head locking member 660 is rotatable about the support shaft 661 and is always urged by the spring member 662 in a direction to lock the engagement pin 613. When the head locking member 660 is rotated against the urging force of the spring member 662, the locking state of the engagement pin 613 by the locking member 660 is released.
[0060]
At this time, the head unit 60 is automatically pushed up to a position where the engagement pin 613 is not locked by the head locking member 660 with the biasing force of the head pop-up spring 654 described above. Therefore, the operation of releasing the engagement pin 613 by the head locking member 660 can be performed with a single touch, and since it is not necessary to support the unit 60 in consideration of the return of the head unit 60, the workability is extremely good.
[0061]
Next, the ribbon mounting unit 70 is provided on the upper surface of the head unit 60 as shown in FIGS. The ribbon mounting unit 70 includes a ribbon housing 710 provided at one end in the width direction of the head unit 60, and a supply side bearing 730 and a take-up side bearing 731 provided side by side at the other end in the width direction.
[0062]
FIG. 20 is a cross-sectional plan view showing the internal structure of the ribbon housing.
As shown in the figure, inside the ribbon housing 710, a supply shaft 711 is rotatably supported on the rear side, and a supply bobbin 712 is attached to the tip of the supply shaft 711. The tip end of the supply bobbin 712 is exposed from the ribbon housing 710 and faces the supply side bearing 730 on the same horizontal plane.
[0063]
On the other hand, inside the ribbon housing 710, on the front side thereof, a ribbon winding drive motor (ribbon winding motor) 713 and the rotational driving force of the ribbon winding motor 713 are transmitted to the winding bobbin 714. A gear mechanism 715 is built in. The leading end of the winding bobbin 714 is also exposed from the ribbon housing 710 and faces the winding-side bearing portion 731 on the same horizontal plane.
[0064]
As shown in FIG. 7, a ribbon tube around which a ribbon-shaped ink ribbon 3 is wound is fixedly fitted. A ribbon shaft 740 has one end fitted and fixed to a supply bobbin 712 and the other end supplied to a supply-side bearing. The unit 730 is rotatably mounted. Further, the winding tube to which the leading edge of the ink ribbon 3 drawn out from the ribbon tube is attached is externally fixed to the winding shaft 741. One end of the winding shaft 741 is fitted and fixed to the winding bobbin 714, and the other end is rotatably mounted on the winding-side bearing portion 731. The ink ribbon 3 drawn from the ribbon tube is disposed via the lower surface of the head unit 60 (that is, the heating element 622 of the thermal head 620). When the take-up shaft 741 is driven to rotate by the rotation of the ribbon take-up motor 713, the ink ribbon 3 on the ribbon shaft 740 side is taken up via the lower surface of the head unit 60.
[0065]
Here, in order to convey the ink ribbon 3 without slack or wrinkles, the ribbon winding is performed so that a constant tension is applied to the ink ribbon 3 from the beginning of winding of the ink ribbon 3 to the winding tube to the end of winding. The rotational torque of the take-off motor 713 is preferably controlled to be constant. For this reason, in the present embodiment, the ribbon winding motor 713 is controlled at a constant current, and even if the winding amount of the ink ribbon 3 is changed by this control method, the rotational torque is constant and the ink ribbon 3 is constant tension. It becomes possible to act.
[0066]
However, various types of ink ribbons 3 having different widths and winding diameters are prepared, and the user selects and mounts ones having an appropriate width and winding diameter as required. Therefore, assuming that the ribbon ribbon motor 713 is controlled at a constant current with a large current value, assuming that the ribbon ribbon 713 has a wide width and a large winding diameter, the rotational torque increases, resulting in a narrow width and a small winding diameter. At the time of mounting, the tension acting on the ink ribbon 3 becomes excessive, and there is a possibility that wrinkles may be generated or the ink ribbon 3 may be broken.
[0067]
Therefore, in the present embodiment, a plurality of combinations are set in advance with respect to the current value to be passed through the brush of the ribbon take-up motor 713 and stored in a memory built in the control box 15 shown in FIG. For example, I ₁ , I ₂ , I ₃ , I ₄ , I ₅ (I ₁ <I ₂ <I ₃ <I ₄ <I ₅ ) Are set in the memory, and when the ink ribbon 3 having a large winding diameter and a wide width is mounted, a large current value (for example, I ₅ It is preferable that a large rotational torque be obtained. Conversely, when the ink ribbon 3 having a small winding diameter and a narrow width is attached, a small current value (for example, I ₁ It is preferable that a large rotational torque be obtained.
[0068]
FIG. 21 is a block diagram showing a control system of the ribbon take-up motor.
The selection of the current value can be performed by the operation panel 13. That is, the current value selected by the operation panel 13 is read from the memory 81 and the data is sent to the control circuit 80. The control circuit 80 drives the ribbon winding motor 713 to rotate with constant current control based on the selection data.
[0069]
Returning to FIG. 20 again, the supply shaft 711 rotatably supported inside the ribbon housing 710 is provided with a brake mechanism having the following structure.
That is, a disc-shaped first friction member 716, an annular second friction member 717, a pressing member 718, and a spring receiving member 719 are respectively fitted on the supply shaft 711, and an annular operation member 720 is further provided. It is screwed.
Among these, the first friction member 716, the pressing member 718, and the spring receiving member 719 are restricted from rotating relative to the supply shaft 711 and rotate integrally with the supply shaft 711. Further, the first friction member 716, the pressing member 718, and the spring receiving member 719 are movable in the axial direction with respect to the supply shaft 711. However, the movement of the first friction member 716 in one direction (the downward direction in the figure) is restricted by contact with a washer 721 attached to the supply shaft 711. In order to allow such rotation restriction and axial movement, the supply shaft 711 has a D-shaped cross section, while the first friction member 716, the pressing member 718, and the spring receiving member 719 Is formed with a D-shaped shaft hole that fits into the D-shaped supply shaft 711.
[0070]
The operation member 720 is formed by molding a plastic material on a metal nut 720a, and the nut 720a is screwed into a screw portion 711a formed on the supply shaft 711. The operation member 720 is formed with a disk-shaped operation portion 720b, and knurled grooves 720c are formed at regular intervals on the outer peripheral surface of the operation portion 720b. The width of the groove 720c is set to such a size that a coin can be inserted as will be described later.
[0071]
In addition, the operation member 720 is formed with one or a plurality of (two in the drawing) arms 720d extending to the outer periphery of the spring receiving member 719, and the engaging portion 720e is bent at the tip of the arm 720d. It is formed. On the other hand, on the outer peripheral surface of the spring receiving member 719, engaging recesses 719a are formed at regular intervals, and when the spring receiving member 719 and the operation member 720 rotate relative to each other as will be described later, the engaging recesses 719a. The engaging portion 720e of the arm 720d is engaged and disengaged to obtain a click feeling.
[0072]
The second friction member 717 is rotatable relative to the supply shaft 711 and is also movable in the axial direction. However, the second friction member 717 is formed with an engaging portion 717a protruding at a part thereof, and this engaging portion 717a is engaged with a stopper portion 710a provided on the ribbon housing 710, Free rotation is regulated.
[0073]
A friction contact portion 716a formed of felt or the like is provided on one side surface of the first friction member 716, and one side surface of the second friction member 717 contacts the friction contact portion 716a.
[0074]
A first elastic member 722 formed of a compression coil spring or the like is provided between the spring receiving member 719 and the pressing member 718. The spring receiving member 719 is received by the operating member 720 with respect to the pressing force received from the first elastic member 722, and the movement in the axial direction is restricted. The pressing member 718 transmits the pressing force received from the first elastic member 722 to the second friction member 717. With this pressing force, the second friction member 717 comes into contact with the friction contact portion 716 a provided on the first friction member 716.
[0075]
When the supply shaft 711 rotates in the supply direction of the ink ribbon 3, the first friction member 716 rotates together with the supply shaft 711, but the second friction member 717 is engaged with a stopper portion 710 a provided on the ribbon housing 710. Are engaged to prevent rotation. For this reason, a frictional force is generated between the friction members 716 and 717, and this frictional force acts on the supply shaft 711 as a braking torque. As a result, a braking action is generated on the supply shaft 711, and an excessive supply of the ink ribbon 3 due to inertia is prevented, and the state of the ink ribbon 3 without slack is maintained.
[0076]
When the supply shaft 711 rotates in the direction opposite to the direction in which the ink ribbon 3 is supplied, the engaging portion 717a formed on the second friction member 717 is rotated away from the stopper portion 710a provided on the ribbon housing 710. And Therefore, the second friction member 717 is biased in a direction to prevent this reverse rotation by a second elastic member 723 formed of a torsion coil spring.
[0077]
Next, a method for adjusting the braking torque with respect to the rotation of the ink ribbon 3 will be described.
As shown in FIG. 22A, the ribbon housing 710 has a notch hole 710b at a position facing the groove 720c formed in the operation portion 720b of the operation member 720, and the coin is formed into a groove through the notch hole 710b. The insertion and the rotation of the operation member 720 are restricted. In this state, when the ribbon shaft 740 fitted and fixed to the supply bobbin 712 is rotated in the supply direction, the supply shaft 711 shown in FIG. 20 is rotated, and the nut 720a of the operation member 720 is attached to the screw portion 711a of the supply shaft 711. It moves relative to the axial direction. With this relative movement, the spring receiving member 719 also moves relative to the operation member 720. Accordingly, the interval between the spring receiving member 719 and the pressing member 718 is expanded or contracted, and the first elastic member 722 is expanded or compressed. As a result, the pressing force transmitted from the first elastic member 722 to the second friction member 717 via the pressing member 718 changes, and the braking torque changes.
[0078]
The braking torque is preferably adjusted according to the mass of the ink ribbon 3. For example, when an ink ribbon 3 having a large winding diameter or width dimension is mounted, the inertial force during rotation increases as the mass increases, so that the braking torque is adjusted to be large, while the ink having a small winding diameter or width dimension is adjusted. Conversely, when the ribbon 3 is mounted, the braking torque may be adjusted to be smaller.
[0079]
When the braking torque is adjusted according to the above-described procedure, the engagement portion 720e of the arm 720d is engaged with and disengaged from the engagement recess 719a with the relative rotation of the spring receiving member 719 and the operation member 720, and a click feeling is obtained. Therefore, the adjustment amount can be grasped sensuously by the number of engagements / disengages.
[0080]
Further, as shown in FIG. 22 (b), the ribbon housing 710 is provided with a scale 710c on the side of the notch hole 710b, and the position of the operation portion 720b visually recognized through the notch hole 710b is indicated by the scale 710c. By adjusting it as a guideline, the adjustment amount of the braking torque can be objectively determined.
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the head unit from falling down vigorously due to its own weight, and it is possible to easily swing the head unit in any direction. Has an excellent effect.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an outline of a line thermal printer according to an embodiment of the present invention.
FIG. 2 is a perspective view showing an appearance of a line thermal printer according to the present embodiment.
FIG. 3 is a perspective view showing an internal structure of the line thermal printer according to the embodiment.
FIG. 4 is a perspective view for explaining a setting procedure of the line thermal printer according to the embodiment.
FIG. 5 is a perspective view for explaining the setting procedure of the line thermal printer following FIG. 4;
6 is a perspective view for explaining the setting procedure of the line thermal printer, following FIG. 5;
FIG. 7 is a perspective view for explaining the setting procedure of the line thermal printer following FIG. 6;
FIG. 8 is a perspective view showing a roll shaft.
FIG. 9 is a plan view showing a roll paper supply unit.
FIG. 10 is a side view of the right roll guide.
FIG. 11 is a plan view showing a lower sensor unit.
FIG. 12 is a sectional side view showing an upper sensor unit and a lower sensor unit.
FIG. 13 is a plan view showing an upper sensor unit.
FIG. 14 is an exploded perspective view showing the head unit.
FIG. 15 is a sectional side view showing the head unit.
16A and 16B are views showing a thermal head pressing unit, in which FIG. 16A is a perspective view showing the unit with a part cut away, and FIG. 16B is a sectional side view.
FIG. 17 is a perspective view showing a back surface of the head unit.
18A and 18B are views showing a hinge portion of the head unit, where FIG. 18A is a front view in an open state, and FIG. 18B is a side view in a closed state.
FIG. 19 is a side view showing a head locking member.
FIG. 20 is a cross-sectional plan view showing an internal structure of a ribbon housing constituting the ribbon mounting unit.
FIG. 21 is a block diagram showing a control system of the ribbon take-up motor.
FIGS. 22A and 22B are diagrams for explaining the operation procedure of the brake mechanism of the ink ribbon built in the ribbon housing, where FIG. 22A is a perspective view and FIG. 22B is an enlarged plan view of a scale.
[Explanation of symbols]
1: Paper transport path
2: Roll paper
3: Ink ribbon
10: Body case
11: Top cover
12: Paper outlet
13: Operation panel
14: Body frame
15: Control box
20: Roll paper supply unit
30: Front unit
31: Platen
32: Paper cutting board
40: Lower sensor unit
41: Lower case
41a: recess
41b: Leg
42: Lower guide
43: Lower guide shaft
44: Lower guide plate
45: Light emitting element
46: First light receiving element
47: Elastic member
50: Upper sensor unit
51: Upper case
52: Upper guide plate
53: Hinge part
54: Guide hole
55: Second light receiving element
56: Support piece
57: leaf spring
58: Scale
60: Head unit
70: Ribbon mounting unit
80: Control circuit
81: Memory
210: Support plate
211: Roll support part
220: Roll axis
221: Bearing
222: Holder disk
223: Fastener
230: Left roll guide
232: Left guide rack
240: Right roll guide
231, 241: recess
242: Right guide rack
243: Fixed operation unit
244: Fixing member
244a: contact portion
250: Guide rail
251: Pinion gear
610: Head support frame
611: long hole
612: Notch
613: engagement pin
620: Thermal head
621: Head support plate
622: exothermic element
623: Bearing portion
624: Lever engaging pin
625: hook
625a: arm
625b: locking portion
630: Thermal head pressing unit
631: Upper case
632: Lower case
633: oblong hole
634: protrusion
635: Fastener
636: engagement protrusion
637: protrusion
638: Compression coil spring
640: Operation lever
641: Spindle
643: long hole
644: Fastener
645: Scale
650: Hinge part
651: Unidirectional torque control mechanism
652: Mechanism body
653: spindle
654: Head pop-up spring
655: Spring receiving portion
660: head locking member
661: spindle
662: Spring member
710: Ribbon housing
710a: Stopper part
710b: Notch hole
710c: Scale
711: Supply shaft
711a: Screw part
712: Supply bobbin
713: Ribbon take-up motor
714: Winding bobbin
715: Gear mechanism
716: First friction member
716a: friction contact portion
717: Second friction member
717a: engagement portion
718: Pressing member
719: Spring receiving member
719a: engaging recess
720: Operation member
720a: nut
720b: operation unit
720c: groove
720d: Arm
720e: engaging portion
721: Washer
722: first elastic member
723: Second elastic member
730: Supply side bearing
731: Winding side bearing
740: Ribbon shaft
741: Winding shaft

Claims (2)

The head unit supports a line thermal head, and the head unit is separated from the platen by a print position where the line thermal head is brought into close contact with the platen by a hinge portion provided between the head unit and the printer main body. In the line thermal printer that can swing between the retracted position,
The hinge portion has a unidirectional torque control mechanism. The unidirectional torque control mechanism is a constant that does not depend on the swing speed when the head unit swings from the retracted position to the print position. When a load direction load torque that is a load torque is applied to the head unit and the head unit swings from the printing position to the retracted position, an unload direction load that is a load torque that is at least smaller than the load direction load torque. The head unit can be swung with torque,
Further, a head locking member for locking the head unit at the printing position, and when the locking by the head locking member is released, the head unit is lifted to a position where it is not locked by the head locking member. With a head pop-up spring,
The head popup spring is constituted by a compression coil spring, Ri Oh provided in the vicinity of the hinge portion,
The line thermal printer according to claim 1 , wherein when the head unit is further opened from a position lifted by the head pop-up spring, the head pop-up spring is separated from the head unit . The line thermal printer according to claim 1 , wherein the hinge portion swings the head unit along a plane substantially orthogonal to the sheet conveyance path.

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