JP2011207109A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal printer capable of optimally controlling the state of ink ribbons in at the various ink ribbons.SOLUTION: A feeding side core 11 is used for winding the ink ribbon 91. A winding side core 12 is used for winding the ink ribbon 91 from the feeding side core 11. A measuring section MS is used for measuring the respective rotation angles S1, S2 of the feeding side core 11 and the feeding side core 12 in the step for winding the ink ribbon 91. A rotation control unit RC controls the rotation of feeding side core 11 or the winding side core 12 when printing based on the respective rotation angle S1, S2 of the feeding side core 11 and the winding side core 12, the area X of one side face of the ink ribbon whole of which is not yet used, and the areas of the respective one side faces of the part of the ink ribbon before use on the feeding side and the part of the ink ribbon after use on the winding side.

Description

  The present invention relates to a thermal printer.

  The thermal printer performs printing by transferring the ink on the ink ribbon to the print medium using a thermal head while transporting the print medium such as paper and the ink ribbon in an overlapped state. In this printing, if the tension applied to the ink ribbon is inappropriate, printing failure may occur. For example, if the tension is too small, the ink ribbon may be wrinkled, and if the tension is excessive, the printing position may be shifted due to slippage between the printing medium and the ink ribbon. There is. Therefore, it is required to control the tension of the ink ribbon to an optimum value.

  A technique for controlling the tension of the ink ribbon is disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-62032. According to this publication, the torque of the motor that transports the ink ribbon is controlled in accordance with the outer diameter of the ink ribbon wound around the supply core, that is, the supply ribbon diameter. The supply ribbon diameter is calculated from the rotation angle of the supply core and the supply amount of the ink ribbon. When this calculation is performed before printing, the ink ribbon is supplied by feeding the ink ribbon idle.

  In the above publication, the amount of ink ribbon supplied is detected by identifying a change in the color of the ink ribbon (yellow, magenta and cyan) or by identifying a mark pattern provided on the ink ribbon with a sensor. In other words, since the interval between each color or the mark pattern in the ink ribbon is constant, the ribbon diameter can be determined from the color portion interval or mark pattern interval and the rotation angle of the supply core by transporting the ribbon before printing. Is detected.

JP 2007-62032 A

  In the technique described in the above publication, the transport distance of the ink ribbon is detected in order to know the outer diameter of the ink ribbon. In detecting the transport distance, a color change or a mark pattern is identified. For this reason, an ink ribbon having a single dyed layer and no mark pattern cannot be used.

  In order to solve such a problem, a technique capable of calculating the outer diameter of the ink ribbon without using information on the transport distance of the ink ribbon is desired. However, it has been difficult to perform such calculation so far because of the influence of deformation before and after using the ink ribbon.

  The present invention has been made in view of the above problems, and an object of the present invention is to calculate the outer diameter of the ink ribbon without using the information on the transport distance of the ink ribbon and optimally control the state of the ink ribbon. It is to provide a thermal printer.

  The thermal printer of the present invention includes a supply side core, a winding side core, a measurement unit, and a rotation control unit. The supply side core is for winding the ink ribbon. The winding side core is for winding the ink ribbon from the supply side core. The measuring unit measures each rotation angle of the supply side core and the take-up side core in the step of winding the ink ribbon. The rotation control unit includes the rotation angle of each of the supply side core and the take-up side core, the area of one side surface of the ink ribbon that has not been used as a whole, the portion before use of the ink ribbon on the supply side, and the use on the take-up side. The rotation of the supply side core or the winding side core is controlled at the time of printing based on the area of one side surface of each finished part.

  According to the thermal printer of the present invention, the value of the area of one side of the unused ink ribbon and the area of one side of each of the unused and used ink ribbons are given in advance, so that the supply side By simply measuring the rotation angle of each of the core and the take-up core, the supply-side outer diameter, which is the outer diameter of the ink ribbon wound around the supply-side core, and the outer diameter of the ink ribbon wound around the take-up core It is possible to know the outer diameter of the winding side. That is, it is possible to optimally control the state of the ink ribbon by calculating the outer diameter of the ink ribbon without using the information on the transport distance of the ink ribbon.

  Preferably, the rotation control unit includes a ribbon diameter calculation unit and a ribbon drive unit. The ribbon diameter calculation unit calculates the rotation angle of each of the supply core and the take-up core, the area of one side of the unused ink ribbon, and the area of one side of each unused and used ink ribbon. Based on this, the supply-side outer diameter, which is the outer diameter of the ink ribbon wound around the supply-side core, and the take-up-side outer diameter, which is the outer diameter of the ink ribbon wound around the take-up core, are calculated. . The ribbon drive unit controls the rotation of the supply side core or the winding side core during printing based on the calculated supply side outer diameter and winding side outer diameter.

  Thereby, the state of the ink ribbon can be optimally controlled according to the supply-side outer diameter and the winding-side outer diameter of the ink ribbon.

  As described above, according to the present invention, it is possible to optimally control the state of the ink ribbon by calculating the outer diameter of the ink ribbon without using the information on the transport distance of the ink ribbon.

1 is a block diagram schematically showing a configuration of a thermal printer in an embodiment of the present invention. FIG. FIG. 2 is a plan view schematically showing an ink ribbon and the vicinity thereof included in the thermal printer in one embodiment of the present invention. It is a fragmentary top view which shows an example of an ink ribbon roughly. It is a fragmentary top view which shows the other example of an ink ribbon roughly. FIG. 10 is a partial plan view schematically showing still another example of an ink ribbon.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the configuration of a thermal printer according to an embodiment of the present invention will be described.

  Referring to FIG. 1, the thermal printer of the present embodiment includes a driven unit AD, a storage unit 23, a measurement unit MS, and a rotation control unit RC.

  With reference to FIG. 2, first, the configuration of the driven unit AD will be described. The driven part AD includes a supply side core 11, a take-up side core 12, a feed roller 13, a paper core 14, a pinch roller 15, a platen roller 16, a thermal head 17, a peeling plate 18, and a ribbon. A guide roller 19, a paper cutter 20, an ink ribbon 91, and a paper 81 (print medium) are included.

Supply-side core 11 has a radius r _c, unused side of the ink ribbon 91 is wound into a cylindrical shape with a thickness r _s. Outer diameter radius of the cylindrical shape, i.e. defined as the supply-side outer diameter R1 (Figure 2) r _c + r _s.

The winding core 12 is for winding the ink ribbon 91 from the supply core 11. The take-up side core 12 has a radius r _c, the spent side of the ink ribbon 91 is wound into a cylindrical shape with a thickness r _t. Outer diameter radius of the cylindrical shape, i.e. defining a r _c + r _t winding side outer diameter R2 (Figure 2).

  One end side (right side in the figure) of the paper 81 is held around the paper core 14 in a roll shape, and the other end side (left side in the figure) is pulled out for printing. The paper cutter 20 is for cutting out the printed paper 81.

  The thermal head 17 is for transferring the ink on the ink ribbon 91 onto the paper 81 by generating heat when energized. Further, the thermal head 17 and the platen roller 16 are configured to be able to sandwich the paper 81 and the ink ribbon 91 stretched between the supply side core 11 and the winding side core 12 by approaching each other. Yes. Furthermore, the thermal head 17 and the platen roller 16 are configured to be able to release the above-described sandwiching of the paper 81 and the ink ribbon 91 by separating from each other. The state in which the thermal head 17 and the platen roller 16 are separated from each other in this way is referred to as a head-up state.

  The feed roller 13 and the pinch roller 15 are arranged so as to sandwich the paper 81. Accordingly, the paper 81 can be transported by rotating the feed roller 13. That is, the sheet 81 can be conveyed by a distance corresponding to the rotation amount of the feed roller 13.

  Next, the storage unit 23 will be described. The memory | storage part 23 can memorize | store the total side area X and the winding thickness coefficient E (change rate).

Total lateral area X, the total area of when the whole ink ribbon 91 is wound on the supply side core 11 in the unused state, one side surface of the ink ribbon 91 (donut-shaped surface in the thickness r _s in FIG. 2) It is.

Wound expansion coefficient E is the total area of one side surface (donut-shaped surface in the thickness r _t in FIG. 2) of the ink ribbon 91 when the whole ink ribbon 91 is wound on the take-up side core 12 with dirty When the total side area Y is taken, it is a value obtained by dividing the total side area Y by the total side area X (Y / X). That is, the winding thickness coefficient E indicates the rate of change of how much the side surface of the ink ribbon 91 increases as the ink ribbon 91 is used.

  For example, if there is no increase or decrease in the side area before and after use of the ink ribbon 91, the winding thickness coefficient E = 1. If this side area increases by 5%, the winding thickness coefficient E = 1.05. Note that when the ink ribbon 91 receives heat from the thermal head 17, the ink ribbon 91 usually changes so that its side area increases. For this reason, the winding weight coefficient E is usually a value larger than 1.

  The measurement unit MS will be described with reference to FIGS. 1 and 2. The measuring unit MS includes a supply-side angle sensor 21s and a winding-side angle sensor 22s (FIG. 2) as the ribbon supply-side rotation angle measuring unit 21 and the ribbon winding-side rotation angle measuring unit 22 (FIG. 1), respectively. Each of the supply-side angle sensor 21 s and the winding-side angle sensor 22 s measures the rotation angles of the supply-side core 11 and the winding-side core 12.

More specifically, the supply-side angle sensor 21 s optically detects a large number of slits (not shown) that are arranged at an equal angle on the outer periphery of the supply-side core 11 and rotate together with the supply-side core 11. It is configured to be able to. Accordingly, the supply-side angle sensor 21s is, by counting the number C ₁ of detected slits, it is possible to measure the rotation angle S1 of the supply-side core 11 (in radians). That is, the supply side angle sensor 21s is a kind of encoder for measuring an angle.

  The above-described slits are attached around the supply-side core 11 at an angle corresponding to one rotation, that is, an angle that divides 2π (radian) into 800 equal parts, for example. In this case, the supply-side angle sensor 21s can measure the rotation angle with a resolution of 2π / 800 (radian).

Take-up angle sensor 22s has the same configuration as the supply-side angle sensor 21s, by counting the number C ₂ of the slit, to measure the rotation angle S2 of the supply-side core 11 (radian) it can.

  Next, the rotation control unit RC will be described. The rotation control unit RC is for controlling the rotation of the supply side core 11 and the take-up side core 12 during printing, and includes a ribbon diameter calculation unit 31, a tension calculation unit 32, a ribbon supply side drive unit 41, A ribbon take-up drive unit 42.

  The ribbon diameter calculation unit 31 includes a rotation angle S1 of the supply side core 11 measured by the ribbon supply side rotation angle measurement unit 21, and a rotation angle of the winding side core 12 measured by the ribbon winding side rotation angle measurement unit 22. The supply-side outer diameter R1 and the winding-side outer diameter R2 are calculated on the basis of S2 and the total side area X and the winding thickness coefficient E stored in the storage unit 23 in advance. Details of this calculation method will be described later.

  The ribbon supply side drive unit 41 has a supply side motor (not shown) for rotationally driving the supply side core 11. The ribbon take-up drive unit 42 includes a take-up motor (not shown) for rotationally driving the take-up core 12. These motors can apply tension to the ink ribbon 91 by applying torque to the supply side core 11 and the take-up side core 12. Therefore, the tension of the ink ribbon 91 depends on the driving conditions of the ribbon supply side drive unit 41 and the ribbon take-up side drive unit 42.

  The tension calculation unit 32 includes a ribbon supply side drive unit 41 and a ribbon take-up side drive unit that optimize the tension of the ink ribbon 91 under conditions of a specific supply-side outer diameter R1 and a take-up side outer diameter R2. 42 drive conditions are calculated. Specifically, for example, when the voltage of the motor in the ribbon supply side drive unit 41 and the ribbon winding side drive unit 42 is controlled by PWM (Pulse Width Modulation), the specific supply side outer diameter R1 and the winding side The duty of the PWM control is calculated so that the tension of the ink ribbon 91 is optimized under the condition of the outer diameter R2.

  Next, a method of calculating the supply side outer diameter R1 and the winding side outer diameter R2 by the ribbon diameter calculation unit 31 will be described in detail.

The lateral area of the supply-side core wound unused in thickness r _s to 11 ink ribbon 91 as shown in FIG. 2 and the area A _s, wound in a thickness r _t on the take-up side core 12 When the lateral area of the used ink ribbon 91 and the area a _t, the following equation (1) is satisfied.

Further, the ratio of the slit numbers C ₁ and C ₂ when the ink ribbon 91 is conveyed by an appropriate amount corresponds to the ratio of the rotation angles S 1 and S 2 of the supply side core 11 and the winding side core 12. Therefore, the following formula (2) is established.

Further, each of the area A _s and A _t, if specific export, the following equation (3) and (4).

  From the equations (1), (3) and (4), the following equation (5) is obtained.

  Further, the formula (2) can be transformed as the following formula (6).

R _s can be eliminated from equation (5) using equation (6). More specific value, the total lateral area X = 5429 (mm ^2), and substituting wound expansion coefficient E = 1.05, 2 equations are obtained about r _t as the following equation (7).

The thickness r _t can be obtained by solving the equation (7). By adding the radius r _c in this thickness r _t, can be obtained supply-side outer diameter R1. Further by substituting the thickness r _t in equation (6), it is possible to obtain the thickness r _s. By adding the radius r _c in the thickness r _s, it is possible to obtain the winding-side outer diameter R2.

As described above, if the number of slits C ₁ and C ₂ corresponding to each of the rotation angles S1 and S2 is counted, the total side area X and the winding weight coefficient E stored in the storage unit 23 in advance are used. The supply side outer diameter R1 and the winding side outer diameter R2 can be calculated.

  Next, the operation of the thermal printer according to the present embodiment will be described with reference to FIGS.

  First, the thermal printer is turned on. The thermal printer immediately after the power is turned on enters an initial state, that is, an uncertain state as to how much the ink ribbon 91 has been used. In other words, the supply-side outer diameter R1 and the winding-side outer diameter R2 of the ink ribbon 91 are indeterminate. Therefore, at this time, the tension calculating unit 32 cannot calculate the driving conditions of the ribbon supply side driving unit 41 and the ribbon winding side driving unit 42 so that the tension of the ink ribbon 91 is optimized.

Next, as a first operation, the winding side core 12 winds the ink ribbon 91 by an appropriate amount. At this time, the rotation angle S1 of the supply side core 11 and the rotation angle S2 of the winding side core 12 are respectively set. Corresponding slit numbers C ₁ and C ₂ are counted. Next, as a second operation, the ink ribbon 91 is rewound. Next, as a third operation, supply at the time of printing based on the number of slits C ₁ and C ₂ counted as described above and the total side area X and the winding weighting factor E stored in the storage unit 23 in advance. The rotation of the side core 11 and the winding side core 12 is controlled. Details of these first to third operations will be described in order below.

First, the first operation will be described.
The thermal head 17 is brought up. As a result, the ink ribbon 91 can move freely independently of the paper 81.

  Next, the take-up core 12 is rotated by an appropriate amount as indicated by an arrow T2 (FIG. 2), whereby the ink ribbon 91 is taken up from the supply-side core 11 to the take-up core 12 by an appropriate amount. .

  Accordingly, the supply side core 11 and the winding side core 12 rotate as indicated by arrows T1 and T2. That is, each of the supply side core 11 and the take-up side core 12 rotates by rotation angles S1 and S2 (FIG. 1).

Next, the rotation angles S1 and S2 are measured by the measurement unit MS (FIG. 1). That is, the supply side angle sensor 21s (FIG. 2) as the ribbon supply side rotation angle measurement unit 21 (FIG. 1) and the winding side angle sensor 22s (FIG. 2) as the ribbon winding side rotation angle measurement unit 22 (FIG. 1). by each of the), the number C ₁ of the slits of the supply-side core 11, the number C ₂ of the slit of the take-up side core 12 is counted. Thus, the first operation is performed.

Next, the second operation will be described.
The supply-side core 11 is rotationally driven so that the conveyance opposite to the conveyance of the ink ribbon 91 in the first operation is performed. That is, the supply side core 11 is rotationally driven in the direction opposite to the arrow T1 in the drawing. As a result, the portion of the ink ribbon 91 that has been sent out from the supply side core 11 by the first operation is rewound onto the supply side core 11. Thus, the second operation is performed.

Next, the third operation will be described.
The thermal head 17 and the platen roller 16 sandwich the paper 81 and the ink ribbon 91 stretched between the supply side core 11 and the take-up side core 12 together.

  Next, the feed roller 13 is driven to rotate so that the paper 81 is conveyed over a desired printing dimension (arrow Rf). As a result, in the vicinity of the feed roller 13, the sheet 81 is conveyed by the printing dimension toward the sheet 81 supply side (right side in the figure), that is, toward the sheet core 14.

  When the paper 81 is transported, the ink ribbon 91 stretched between the supply core 11 and the take-up core 12 is sandwiched between the thermal head 17 and the platen roller 16 together with the paper 81. The paper 81 is conveyed. That is, the ink ribbon 91 stretched between the supply side core 11 and the winding side core 12 is wound from the supply side core 11 to the winding side core 12 by the printing dimension.

  The above conveyance is performed under printing conditions. That is, the thermal head 17 is energized so that heat generation sufficient to transfer the ink on the ink ribbon 91 is generated according to the print pattern. As a result, printing of the paper 81 is performed.

At the time of printing, that is, when the paper 81 and the ink ribbon 91 are conveyed under the printing conditions, the rotation control unit RC determines the slits corresponding to the values obtained by the first operation, that is, the rotation angles S1 and S2, respectively. The rotation of the supply side core 11 and the winding side core 12 is controlled based on the numbers C ₁ and C ₂ and the total side area X and the winding weight coefficient E stored in the storage unit 23 in advance. As a result, the tension of the ink ribbon 91 is optimized, and printing with high accuracy becomes possible. This control will be described in detail below.

First, the ribbon diameter calculation unit 31 corresponds to the number of slits C ₁ corresponding to the rotation angle S1 and the rotation angle S2 from the ribbon supply side rotation angle measurement unit 21 and the ribbon winding side rotation angle measurement unit 22, respectively. Information on the number of slits C ₂ is received. The ribbon diameter calculation unit 31 receives information on the total side area X and the winding thickness coefficient E from the storage unit 23. Next, the ribbon diameter calculation unit 31 calculates the supply-side outer diameter R1 and the winding-side outer diameter R2 based on the number of slits C ₁ and C ₂ , the total area X, and the winding thickness coefficient E.

  The tension calculation unit 32 receives information on the supply-side outer diameter R1 and the winding-side outer diameter R2 from the ribbon diameter calculation unit 31. Based on the supply-side outer diameter R1 and the winding-side outer diameter R2, the tension calculator 32 optimizes the tension of the ink ribbon 91 under the conditions of the supply-side outer diameter R1 and the winding-side outer diameter R2. The drive conditions of the ribbon supply side drive unit 41 and the ribbon take-up side drive unit 42 are calculated. Specifically, for example, when the voltage applied to the motor is controlled by PWM (Pulse Width Modulation), the tension of the ink ribbon 91 is optimized under the conditions of the supply-side outer diameter R1 and the winding-side outer diameter R2. The PWM control duty is calculated.

  The ribbon supply side drive unit 41 and the ribbon take-up side drive unit 42 receive from the tension calculation unit 32 information on drive conditions that can optimize the tension of the ink ribbon 91. Based on this driving condition, the ribbon supply side drive unit 41 and the ribbon winding side drive unit 42 respectively control the rotation of the supply side core 11 and the winding side core 12. More specifically, each of the ribbon supply side drive unit 41 and the ribbon winding side drive unit 42 controls the torque of the motor that drives the supply side core 11 and the winding side core 12. Thereby, the tension of the ink ribbon 91 stretched between the supply side core 11 and the winding side core 12 is optimized to a value suitable for printing. Therefore, printing immediately after the initial state can be performed with high accuracy. Thus, the third operation is performed.

In the third operation and the printing operation performed thereafter, the number of slits C ₁ corresponding to each of the rotation angles S1 and S2 is performed in a similar manner to the first operation while performing printing. And C ₂ can be counted. By using the slit numbers C ₁ and C ₂ , the tension of the ink ribbon 91 at the time of printing can always be kept optimal.

According to the present embodiment, the total side area X and the winding thickness coefficient E are stored in the storage unit 23 in advance, so that the number of slits C ₁ of each of the supply side core 11 and the take-up side core 12 is C _1. And C ₂ (that is, rotation angles S1 and S2) can be measured to know the supply-side outer diameter R1 and the winding-side outer diameter R2. By using the supply-side outer diameter R1 and the winding-side outer diameter R2, the tension of the ink ribbon 91 can be controlled by driving and controlling the supply-side core 11 and the winding-side core 12.

  As described above, in this control, there is no need to measure the transport distance of the ink ribbon 91. Therefore, various ink ribbons can be used without limitation. For example, even a monochromatic ribbon that is difficult to detect the transport distance by an optical sensor can be used.

  The ink ribbon 91 wound around the take-up core 12 without being used for printing in the first operation is rewound in the second operation, and is used for printing in the third operation. . Therefore, the ink ribbon 91 wound up in the first operation is not wasted.

  Although the case where the tension calculation unit 32 calculates the duty of the PWM control is illustrated, the condition calculated by the tension calculation unit 32 is not limited to the PWM duty. In other words, the conditions calculated by the tension calculating unit 32 are such that the ribbon supply side drive unit 41 and the ribbon take-up side drive unit 42 and the ribbon take-up side drive unit 42 can optimize the tension of the ink ribbon 91. Any condition may be used as long as it is a condition for controlling the rotation of the unit 42. For example, an analog control voltage value may be calculated.

  Further, although the case where the ink ribbon 91 (FIG. 3) that is a single color and does not have a mark pattern has been described, for example, the ink ribbon 92 (FIG. 4) or the ink ribbon 93 (FIG. 5) is used instead of the ink ribbon 91. May be used. The ink ribbon 92 has dyed layers 71Y, 71M and 71C having different colors. The ink ribbon 93 has a mark pattern 72.

  Moreover, although the case where the slit which rotates with the supply side core 11 and the winding side core 12 was detected in order to measure each rotation angle S1 and S2 of the supply side core 11 and the winding side core 12 was demonstrated, instead For example, a slit attached to a motor that drives each of the supply side core 11 and the winding side core 12 may be detected. In this case, the rotation angles S1 and S2 can be calculated by measuring the rotation angle of the motor.

  The initial state of the thermal printer has been described immediately after the power is turned on. However, the initial state is not limited to this. For example, immediately after the possibility that the ink ribbon 91 has been replaced has occurred, The printer is in the initial state. For example, when the cover of the ink ribbon 91 is opened and closed, it can be said that the ink ribbon 91 may have been replaced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be applied particularly advantageously to a thermal printer.

  DESCRIPTION OF SYMBOLS 11 Supply side core, 12 Winding side core, 13 Feed roller, 14 Paper core, 15 Pinch roller, 16 Platen roller, 17 Thermal head, 19 Ribbon guide roller, 21 Ribbon supply side rotation angle measurement part, 21s Supply side angle sensor , 22 Ribbon take-up side rotation angle measurement unit, 22s take-up side angle sensor, 23 storage unit, 31 ribbon diameter calculation unit, 32 tension calculation unit, 41 ribbon supply side drive unit, 42 ribbon take-up side drive unit, 71, 71C, 71M, 71Y Dyeing layer, 72 mark pattern, 81 paper (printing medium), 91-93 ink ribbon, AD driven part, MS measuring part, R1 supply side outer diameter, R2 take-up side outer diameter, RC rotation control Part, S1, S2 rotation angle.

Claims (1)

A supply-side core for winding the ink ribbon;
A winding side core for winding the ink ribbon from the supply side core;
A measuring unit that measures the rotation angles of the supply side core and the winding side core in the step of winding the ink ribbon;
The rotation angle of each of the supply side core and the take-up side core, the area of one side surface of the ink ribbon that is not used as a whole, the portion before use of the ink ribbon on the supply side, and the used side on the take-up side And a rotation control unit that controls the rotation of the supply-side core or the winding-side core during printing based on the area of one side surface of each of the portions.

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