JP3701869B2 - Ink ribbon transfer mechanism of printing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink ribbon transfer mechanism of a printing apparatus suitable for printing on a relatively small size paper such as a business card or a postcard.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a printing apparatus that performs printing on a relatively small size paper such as a business card or a postcard is known from, for example, Japanese Patent Laid-Open No. 2-206573.
[0003]
In this type of printing apparatus, normally, sheets are sequentially sent out from a paper feeding mechanism on which a large number of papers are set, and the fed-out paper is transported to a printing mechanism by a pre-stage transport mechanism, and a print head (thermal head) and ink Printing is performed by a thermal transfer method using a ribbon. The printed paper is then transported by the subsequent transport mechanism and discharged onto the paper discharge tray. In this case, when the sheet is conveyed to the printing mechanism and the sheet is placed on the platen, the printing unit including the print head and the ink ribbon at the release position is displaced to the set position, and the printing unit is pressed with a pressure spring (pressurization). The printing is performed by pressing the sheet with the member.
[0004]
[Problems to be solved by the invention]
By the way, in this type of printing apparatus, it is necessary to suppress the consumption of the ink ribbon outside the printing region as much as possible to avoid the generation of a waste ink ribbon. Therefore, normally, when the printing area is completed, the printing unit is quickly released from the paper and the ink ribbon feeding operation is stopped.
[0005]
However, the conventional printing apparatus has a problem that when the printing unit is released, dirt such as black streaks due to the ink ribbon adheres to the paper and the printing quality is deteriorated. FIG. 7A shows measured data of the acceleration G added to the printing unit during the printing operation. When the printing unit at the release position is displaced from time to, first, the release motor An acceleration Ga at the time of start-up is generated, and thereafter an acceleration Gb is generated when the printing unit comes into contact with the paper on the platen. When the print area is released and the printing section is released, acceleration Ge is generated when the printing section is separated from the paper, and the vibration (impact) at this time becomes a major factor of contamination. FIG. 7B shows the detection result of the reference position sensor that detects the reference position of the printing unit, and Xs shows the detected reference position. Further, FIG. 7C shows the operating state of the release motor, Zs is the operating period when the printing unit at the release position is displaced to the set position, and Zr is the displacement of the printing unit at the set position to the release position. The operating period is shown.
[0006]
On the other hand, in order to solve this problem, the pressure applied when the print unit is pressed against the paper and the ribbon tension that increases the pressure-bonding property to the print head are usually adjusted. Since the rotation speed (rotation torque) of the shaft differs at the start and end of winding of the ink ribbon, for example, even if the ribbon tension is set (adjusted) to the optimal value, the optimal state depends on the winding amount of the winding shaft. There was a problem that would shift.
[0007]
The present invention solves such problems in the prior art, optimizes the change in the rotational torque of the take-up shaft, and maintains a substantially constant ribbon tension from the start to the end of winding of the ink ribbon. An object of the present invention is to provide an ink ribbon transfer mechanism of a printing apparatus that can be realized easily and at low cost.
[0008]
[Means for Solving the Problems and Embodiments]
In the present invention, when the ink ribbon transfer mechanism 1 of the printing apparatus M that winds the ink ribbon 3 supplied from the supply shaft 2 and printed on the paper P by the winding shaft 4 is configured, the winding shaft is driven. The motor 5, the rotation transmission mechanism 6 interposed between the winding shaft drive motor 5 and the winding shaft 4, and the rotation transmission mechanism 6 provided in the rotation transmission mechanism 6 increase as the rotational speed of the winding shaft 4 increases. A speed-dependent oil-type rotary damper 7d (first torque limiter 7) that limits the rotational torque of the winding shaft 4 so as to increase the load torque, and a speed-independent type that limits the rotational torque of the winding shaft 4. And a second torque limiter 8.
[0009]
In this case, according to a preferred embodiment, the second torque limiter 8 can use a spring-type slip clutch 8c. On the other hand, the supply shaft 2 can be provided with a speed-independent third torque limiter 9 that applies a constant back tension to the ink ribbon 3 to be supplied. The third torque limiter 9 includes a spring. A type slip clutch 9c can be used.
[0010]
As a result, the rotational output of the take-up shaft drive motor 5 (second torque limiter 8) has a constant rotational torque characteristic, but the oil-type rotary damper (first torque limiter 7) has a rotational speed of the take-up shaft 4. Therefore, the winding shaft 4 generates an ideal rotational torque that is small at the beginning of winding and increases at the end of winding, so that the winding of the ink ribbon 3 on the winding shaft 4 increases. Regardless of the diameter, a substantially constant ribbon tension is maintained from the beginning to the end of winding.
[0011]
【Example】
Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.
[0012]
First, in order to facilitate understanding of the present invention, an outline of the printing apparatus M will be described with reference to FIG.
[0013]
The printing apparatus M includes a main body lower portion 71 and a main body upper portion 72 that opens and closes up and down with the hinge portion 70 at the rear of the main body lower portion 71 as a fulcrum. The printing apparatus M shown in FIG. 6 has a front surface portion Mf on the right side, and a paper feed mechanism 73 is disposed on the front surface portion Mf, and the front transport mechanism 74 and the print mechanism are moved from the paper feed mechanism 73 toward the rear. 75, a rear conveyance mechanism 76 and a paper discharge tray mechanism 77 are sequentially arranged. Reference numeral 78 denotes a control unit, and 79 denotes an operation panel.
[0014]
The paper feed mechanism 73 includes a paper feed guide mechanism 80 for setting a large number of papers P ... and a paper feed roller mechanism 81 for feeding the paper P one by one from the many papers P ... set in the paper feed guide mechanism 80. Prepare. The paper feed guide mechanism 80 includes a paper feed tray 83 that can be raised by the paper feed elevator mechanism 82 and lowered by manual operation. A large number of sheets P are stacked on the paper feed tray 83 and set. Is done. The sheets P that can be set are a horizontally placed business card Pa, a vertically placed postcard Pb, and a vertically placed envelope Pc. The upper surface position of the paper P is detected by a sensor, and the feed elevator mechanism 82 is driven and controlled, so that the height is always maintained within a certain range. On the other hand, the paper feed roller mechanism 81 is in contact with the uppermost surface of the set paper P, and feeds the paper P ... forward in the transport direction. The feed roller 85 is arranged in front of the pick-up roller 84 in the transport direction. A retard roller 86 is provided below the roller 85, and the paper P is separated by the feed roller 85 and the retard roller 86 and fed forward one by one.
[0015]
The pre-stage transport mechanism 74 is configured by sequentially arranging a takeaway roller mechanism 87, a pre-registration roller mechanism 88, and a registration roller mechanism 89 in the horizontal direction, and prints a sheet P ... sent from the paper feed roller mechanism 80. It has the function to convey up to. The intervals between the roller mechanisms 87 to 89 are set to be shorter than the minimum size of the paper P to be conveyed. In particular, the pre-registration roller mechanism 88 and the registration roller mechanism 89 have a skew correction function that keeps the angle (orientation) of the transported paper P ... constant and a gap between the transported paper P ... by controlling the rotation operation. In addition, a transport interval correction function for reducing the interval is provided.
[0016]
Next, the configuration of the printing mechanism 75 that is suitable in combination with the ink ribbon transfer mechanism 1 according to the present embodiment will be described more specifically with reference to FIGS. 3 and 4.
[0017]
Reference numeral 21 denotes a horizontal support shaft disposed below the paper feed roller mechanism 81, and one end portion of the cassette loading frame 22 is rotatably attached to the support shaft 21 via a bearing. The cassette loading frame 22 has a cassette loading section 22s for loading the ink ribbon cassette C.
[0018]
On the other hand, an elevating drive unit 23 is disposed below the other end of the cassette loading frame 22. The elevating drive unit 23 includes a release motor 24 using a stepping motor, an eccentric cam 25, a rotation transmission gear mechanism unit 26 for transmitting the rotation of the release motor 24 to the rotation shaft 25s of the eccentric cam 25, and the eccentric cam 25. A follower 27 fixed to the lower surface of the cassette loading frame 22 to be joined is provided. The driven portion 27 includes an upper engagement portion 27u having a V surface on the lower surface and a lower engagement portion 27d having a V surface on the upper surface, and the upper engagement portion 27u and the lower engagement portion 27d. An eccentric cam 25 is arranged between them. Accordingly, when the release motor 24 is driven and controlled, the eccentric cam 25 rotates, and the other end portion side of the cassette loading frame 22 is moved up and down according to the rotation angle of the eccentric cam 25. A fan-shaped shutter 31 is fixed to the rotating shaft 25s, and a transmission type optical sensor 32 whose optical path is opened and closed by the shutter 31 is attached. Thus, a reference position sensor 33 that detects a reference position Xs (see FIG. 7) of the printing unit 12 including the print head 11 and the ink ribbon 3 described later is configured.
[0019]
On the other hand, 35 is a head support frame. The head support frame 35 is formed in a U shape when viewed from the side. One end of the head support frame 35 is pivotally attached to the support shaft 21 via a bearing, and the other end passes through the lower portion of the cassette loading frame 22. Bring it up. As shown in FIG. 4, the print head 11 is supported on the upper end of the other end of the head support frame 35 via a head support mechanism 36. In this case, the head support mechanism portion 36 rotatably supports the brackets 40 of the main base portion 39 via the support shaft 38 on the brackets 37 formed on the upper end of the other end portion of the head support frame 35. One end of the print head 11 having the print head main body 11o is rotatably supported through one end of the auxiliary base portion 15 fixed on the main base portion 39 via the shaft portion 41. Further, an opening window 42 is formed in the main base portion 39, and a regulating shaft 43 provided in the print head 11 is accommodated in the opening window 42. A pair of left and right auxiliary pressure springs (auxiliary pressure members) 14 are interposed between the other side of the auxiliary base portion 15 and the other side of the print head 11. The head support mechanism 36 has a positioning function with respect to the print head 11. The print head 11 uses a C-end surface type thermal head so that printing can be reliably performed even on thick or hard paper P such as business cards and postcards. Further, when a C-end surface type thermal head is used, curling is likely to occur on the paper P. Therefore, the platen 10 is prevented from being curled by using a rubber roller having a rubber hardness of 80 degrees or more. The print head 11 is located directly below the platen 10.
[0020]
Further, as shown in FIG. 4, the lower spring receiving portion 44 is fixed to the cassette loading frame 22, and the upper spring receiving portion 45 facing the lower spring receiving portion 44 is opposed to the head support frame 35. And a pair of left and right main pressure springs (main pressure members) 13 are interposed between the upper spring receiving portion 45 and the lower spring receiving portion 44. The cassette loading frame 22 is provided with a stopper 46 for restricting the upward displacement of the head support frame 35, and a spring 47 is provided between the fixed chassis and the cassette loading frame 22 as shown in FIG. It is installed and the cassette loading frame 22 is urged upward.
[0021]
In this case, the auxiliary pressure spring 14 is set to a sufficiently smaller pressure than the main pressure spring 13. FIG. 5 is a schematic diagram of FIG. 4 in which a part of the printing mechanism 75 is extracted. In a state in which the printing unit 12 is displaced to the release position, the upper spring receiving unit 45 is locked to the stopper 46 by the elastic force of each of the pressure springs 13, 14. ... locked to the upper side. If the printing unit 12 is displaced from this state to the set position indicated by a solid line, that is, the position where the printing unit 12 is pressed against the paper P on the platen 10, the pressure springs 13 ..., 14 ... are compressed. In this case, both the compression amount Em of the main pressure springs 13 and the compression amount Es of the auxiliary pressure springs 14 can be set around 2 [mm] as a guideline. Is approximately 1 [MPa], and the pressure applied to the auxiliary pressure springs 14 is approximately 0.2 [MPa], that is, approximately 1/5 of the main pressure springs 13.
[0022]
On the other hand, the control unit 78 has various setting functions, storage functions, calculation functions, and control functions, and executes the release method according to the present embodiment by sequence control. The control unit 78 is connected to the release motor 24 and the transmissive optical sensor 32 described above, and is also connected to a registration sensor 48 that detects the front end of the conveyed paper P.
[0023]
With the above configuration, the support shaft 21, the cassette loading frame 22 supported by the support shaft 21 and provided with the driven portion 27 at the other end, and the head support frame 35 that supports the print head 11 are connected to the ink ribbon 3 and the print. A transmission mechanism 49 that displaces the head 11 together is configured. The transmission mechanism 49 is a release mechanism that performs pressure contact and release of the print head 11 against the paper P on the platen 10 by transmitting the lift displacement of the driven portion 27 by the lift drive unit 23 to the print head 11. .
[0024]
Next, the configuration and function of the ink ribbon transfer mechanism 1 according to this embodiment will be described with reference to FIGS. 1 and 2.
[0025]
In the ink ribbon transfer mechanism 1 shown in FIG. 1, reference numeral 50 denotes a take-up shaft rotation driving unit that drives the ink ribbon cassette C loaded in the cassette loading unit 22s. Reference numeral 4 denotes a winding shaft to be mounted on the winding reel of the cassette C, and reference numeral 2 denotes a supply shaft to be mounted on the supply reel of the cassette C. The take-up shaft 4 has an integral driven gear 51, and the rotation of a drive gear 52 provided on the rotary shaft of the take-up shaft drive motor 5 is transmitted to the driven gear 51 via the rotation transmission mechanism 6. Is done. The rotation transmission mechanism 6 includes a first gear 6a, a second gear 6b, a third gear 6c, a fourth gear 6d, a fifth gear 6e, a sixth gear 6f, and a seventh gear 6g, and is driven by the first gear 6a. The gear 52 meshes, and the driven gear 51 meshes with the seventh gear 6g.
[0026]
A speed-independent second torque limiter 8 is interposed between the first gear 6a and the second gear 6b. As the second torque limiter 8, a spring-type slip clutch 8c can be used. As a result, when the rotation transmission is performed but the rotation torque equal to or higher than the set rotation torque is applied, the slip occurs and the rotation torque is limited to a constant rotation torque. Further, the input gear 54 provided on the input shaft 53 of the speed-dependent first torque limiter 7 is engaged with the fourth gear 6d. As the first torque limiter 7, an oil-type rotary damper 7d can be used. The oil-type rotary damper 7d has a characteristic in which silicone oil is sealed inside, and the generated rotational torque (load torque) increases as the rotational speed of the winding shaft 4 increases as indicated by Kd in FIG. On the other hand, the rotational output of the second torque limiter 8 exhibits a constant rotational torque characteristic as indicated by Ko in FIG. Therefore, by providing a speed-independent spring-type slip clutch 8c and a speed-dependent oil-type rotary damper 7d and combining the characteristics of both, the rotational speed of the winding shaft 4 can be different at the beginning and end of winding. As shown by Ks in FIG. 2, the rotational torque of the winding shaft 4 is small at the start of winding and increases as the winding ends. Therefore, if the ribbon tension is set (adjusted) to an optimum value, an ideal ribbon tension (tensile force) that is substantially constant from the start to the end of winding regardless of the winding diameter of the ink ribbon 3 on the winding shaft 4. Is maintained.
[0027]
Reference numeral 55 denotes a slip clutch mechanism that uses a spring-type slip clutch 9 c that receives rotation from an output gear 56 provided on the supply shaft 2, and applies a third back tension to the ink ribbon 3 to be supplied. A torque limiter 9 is configured. Reference numeral 57 denotes a guide shaft for guiding the ink ribbon 3, and 58 denotes a guide plate for guiding the ink ribbon 3.
[0028]
Next, the operation of the printing mechanism 75 including the ink ribbon transfer mechanism 1 according to the present embodiment will be described with reference to FIGS.
[0029]
First, when the power is turned on, the cassette loading frame 22 is in the lowered position shown by the solid line in FIG. Accordingly, both the ink ribbon 3 (cassette C) and the print head 11 constituting the printing unit 12 are lowered and are at a release position separated from the platen 10.
[0030]
If the paper P is transported from the pre-stage transport mechanism 74 now, the front end of the paper P is detected by the registration sensor 48. Thereby, the time measurement is started by the timer function of the control unit 78. When the preset first set time Ta has elapsed, the rotation of the registration roller mechanism 89 driven by a registration motor (not shown) is stopped. Thereafter, when the second set time Tb has elapsed, the registration roller mechanism 89 is driven to rotate. Thus, in order to temporarily stop the rotation of the registration roller mechanism 89, the front end of the sheet P hits the stopped registration roller mechanism 89 and the sheet P is bent. At this time, when the front end of the sheet P hits the registration roller mechanism 89, the skew is corrected so that the front end is parallel to the axial direction of the registration roller mechanism 89, and the bending is within the bending allowable space Rw provided by the guide plate. To escape. Then, after this bending occurs, the registration roller mechanism 89 starts to rotate and starts to convey the paper P. Accordingly, the second set time Tb is set to a time during which the sheet P is moderately bent.
[0031]
If the third set time Tc has elapsed since the registration sensor 48 detected the paper P, the control unit 78 activates the release motor 24. As a result, the eccentric cam 25 rotates and the follower 27 is displaced upward to raise the cassette loading frame 22. In this case, the third set time Tc is set in consideration of the distance at which the front end of the conveyed paper P is positioned a predetermined distance ahead of the pressure contact position of the ink ribbon 3 with respect to the platen 10. As a result, when the cassette loading frame 22 is raised, the ink ribbon 3 is always pressed against the lower surface of the paper P. Even when the thick paper P is used, the paper P The problem that the front end of the battery collides and gets dirty is avoided.
[0032]
On the other hand, the shutter 31 also rotates together with the rotation of the eccentric cam 25. If the shutter 31 rotates by a certain angle and the end of the shutter 31 is detected by the transmissive optical sensor 32, this position becomes the reference position Xs (see FIG. 7). When the reference position Xs is reached, the release motor 24 is operated for the first setting step (number of pulses) set in advance, and then stopped. As a result, the printing unit 12 rises to the set position and presses against the paper P.
[0033]
In this case, as shown in FIG. 5, the lower spring receiving portion 44 fixed to the cassette loading frame 22 is displaced upward from the lowest position Xf to the highest position Xa. At this time, first, the print head 11 rises from the release position Xg and comes into contact with the paper P on the platen 10. Further, when the lower spring receiving portion 44 rises from the second position Xc to the first position Xb, the auxiliary base portion 15 rises from the lowered position Xe to the raised position Xd, and the auxiliary pressure spring 14 having a small pressure is compressed. . The amount of compression at this time is Es, and the total length of the auxiliary pressure spring 14 is compressed from Lsp to Ls. At this time, the restriction shaft 43 is locked to the lower side of the restriction window 42. Further, when the lower spring receiving portion 44 is raised from the first position Xb to the highest rise position Xa, the main pressure spring 13 is compressed because the restriction shaft 43 is locked to the lower side of the restriction window 42. The compression amount at this time is Em, and the entire length of the main pressure spring 13 is compressed from Lmp to Lm. As a result, the print head 11 is pressurized only by the main pressure spring 13, and the print head 11 is pressed against the paper P by the main pressure spring 13 with a pressurizing force of approximately 1 [MPa].
[0034]
On the other hand, printing is performed on the paper P by the printing unit 12. When printing (printing area) is completed, a print end command is output and the release operation is started. First, the release motor 24 is activated by outputting a print end command. At this time, the release motor 24 is temporarily stopped after being operated for a preset second setting step (number of pulses), and the release motor 24 is restarted after a preset pause time Ts has elapsed. In this case, the timing for stopping the release motor 24 is set immediately before the printing unit 12 leaves the paper P. That is, the eccentric cam 25 is rotated by the activation of the release motor 24 and the cassette loading frame 22 is lowered, but the printing unit 12 is in pressure contact with the paper P by the elastic return of the auxiliary pressure spring 14 and the main pressure spring 13. Since the printing unit 12 is separated from the sheet P from the position where the cassette loading frame 22 is lowered by the compression amount Es + Em, the operation of the release motor 24 is stopped immediately before the cassette loading frame 22 finishes moving down Es + Em. The lowered position of the cassette loading frame 22 can be accurately known based on the reference position Xs. In addition, the rest time Ts can be set to a relatively short time because it is sufficient that the vibration (impact) associated with the elastic return of the pressure spring 13 can be eliminated. Therefore, since the release operation of the printing unit 12 is stopped for the pause time Ts immediately before the release from the paper P, the vibration (impact) accompanying the elastic return of the pressure spring 13 is absorbed within the pause time Ts.
[0035]
On the other hand, when the release motor 24 is activated, the eccentric cam 25 is rotated, and the cassette loading frame 22 is lowered. When the cassette loading frame 22 is lowered, the lower spring receiving portion 44 is lowered, and when the lower spring receiving portion 44 is lowered from the most elevated position Xa to the first position Xb, the main pressure spring 13 is first extended. That is, the total length of the main pressure spring 13 extends from Lm to Lmp. At this time, the upper spring receiving portion 45 is locked to the stopper 46. Further, when the lower spring receiving portion 44 is lowered from the first position Xb to the second position Xc, the main pressure spring 13 does not expand any more, and the auxiliary pressure spring 14 expands. That is, the total length of the auxiliary pressure spring 14 extends from Ls to Lsp. At this time, the restriction shaft 43 is locked to the upper side of the restriction window 42.
[0036]
Thereafter, when the lower spring receiving portion 44 is further lowered from the second position Xc to the lowest lowered position Xf, the printing portion 12 is separated from the paper P and reaches the release position. That is, the print head 11 reaches the release position Xg that is lowered by the stroke Lr from the press-contacted set position. The release motor 24 is operated for a preset third setting step (number of pulses) after the restart described above, and then stopped.
[0037]
According to such a printing mechanism 75, when the printing unit 12 is released, the main pressure springs 13 are first elastically restored, and then the auxiliary pressure springs 14 are elastically restored. The vibration (impact) generated when the paper leaves the paper P is based only on the auxiliary pressure springs 14 with a small applied pressure, and the vibration (impact generated when only the main pressure springs 13 with a large applied pressure are used. ) Greatly reduced. Accordingly, waste of the ink ribbon can be eliminated, resource saving and running cost reduction can be achieved, and adhesion of stains to the paper can be eliminated to improve the print quality, and it can be realized easily and at low cost. In particular, if the above-described rest time Ts is set during the release operation, the vibration accompanying the elastic return of the auxiliary pressure springs 14 is further absorbed within the rest time Ts. And a synergistic effect associated with setting the rest time Ts.
[0038]
By the way, since the printing mechanism 75 includes the ink ribbon transfer mechanism 1 according to the present embodiment, a further preferable synergistic effect can be obtained. That is, if the ink ribbon transfer mechanism 1 according to the present embodiment is not used, the ribbon tension varies depending on the winding amount of the winding shaft 4 during the release operation. Even if the optimum adjustment is made for Ts or the like, there arises a problem that the optimum state is deviated depending on the winding amount. However, in the ink ribbon transfer mechanism 1 according to this embodiment, the speed-dependent spring-type slip clutch 8c and the speed-dependent oil-type rotary damper 7d are provided to combine the characteristics of both, so that the winding shaft 4 can be optimized, and the ribbon tension can be maintained substantially constant from the start to the end of winding. Accordingly, by providing the printing mechanism 75 with the ink ribbon transfer mechanism 1 according to the present embodiment, the setting (adjustment) of the pressure springs 13..., 14. It is always possible to maintain the optimum state without being influenced by the above.
[0039]
The embodiment has been described in detail above, but the present invention is not limited to such an embodiment, and the detailed configuration, shape, material, numerical value, technique, and the like are within the scope not departing from the gist of the present invention. It can be changed, added, or deleted arbitrarily. For example, although the pressurizing members are exemplified by the pressurizing springs 13... 14, they can be replaced by other pressurizing members such as pressurizing leaf springs. Although a stepping motor is used as the release motor 24, the use of other types of motors is not excluded. Although the case where both the speed-dependent first torque limiter 7 and the speed-independent second torque limiter 8 are used is shown, the speed-dependent first torque limiter 7 is added to the speed-independent torque limiter. When the function is included, only the first torque limiter 7 may be used. Furthermore, although the case where the spring-type slip clutches 8c and 9c are used as the second torque limiter 8 and the third torque limiter 9 has been illustrated, they can be replaced by other functional components having the same functions.
[0040]
【The invention's effect】
Thus, the ink ribbon transfer mechanism of the printing apparatus according to the present invention includes a take-up shaft drive motor, a rotation transmission mechanism portion interposed between the take-up shaft drive motor and the take-up shaft, and the rotation transmission mechanism portion. The speed-dependent oil rotary damper that limits the rotational torque of the take-up shaft so as to increase the generated load torque as the rotational speed of the take-up shaft increases, and the rotational torque of the take-up shaft Because it has a speed-independent second torque limiter, it can optimize the change in the rotational torque of the take-up shaft and keep the ribbon tension almost constant from the beginning to the end of winding. There is a remarkable effect that it can be realized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an ink ribbon transfer mechanism according to a preferred embodiment of the present invention;
FIG. 2 is a diagram for explaining the operation of the ink ribbon transfer mechanism;
FIG. 3 is an operation explanatory diagram including a printing mechanism including the ink ribbon transfer mechanism and a control system;
FIG. 4 is an enlarged partial cross-sectional view showing an essential part of the printing mechanism;
FIG. 5 is a schematic diagram of FIG. 4 for explaining the operation of the printing mechanism;
FIG. 6 is a schematic diagram of a printing apparatus including the ink ribbon transfer mechanism;
FIG. 7 is a timing chart showing the state of each part when using a printing mechanism according to a conventional technique;
[Explanation of symbols]
1 Ink ribbon transfer mechanism
2 Supply shaft
3 Ink ribbon
4 Winding shaft
5 Winding shaft drive motor
6 Rotation transmission mechanism
7 First torque limiter
7d Oil type rotary damper
8 Second torque limiter
8c Spring type slip clutch
9 Third torque limiter
9c Spring type slip clutch
P paper
M printing device

Claims (4)

  In an ink ribbon transfer mechanism of a printing apparatus that winds an ink ribbon supplied from a supply shaft and printed on paper by a winding shaft, the winding shaft driving motor, the winding shaft driving motor, and the winding shaft The rotation transmission mechanism portion interposed between the shafts, and the rotation torque of the winding shaft is limited so that the load torque generated as the rotation speed of the winding shaft increases as the rotation transmission mechanism portion is provided in the rotation transmission mechanism portion. An ink ribbon transfer mechanism for a printing apparatus, comprising: a speed-dependent oil rotary damper (first torque limiter); and a speed-independent second torque limiter for limiting the rotational torque of the winding shaft. .   The ink ribbon transfer mechanism of a printing apparatus according to claim 1, wherein the second torque limiter uses a spring-type slip clutch.   2. The ink ribbon transfer mechanism of a printing apparatus according to claim 1, wherein a speed-independent third torque limiter for applying a constant back tension to the supplied ink ribbon is attached to the supply shaft.   4. The ink ribbon transfer mechanism of a printing apparatus according to claim 3, wherein the third torque limiter uses a spring type slip clutch.

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