JP2001315393A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer printer in which generation of smudge can be eliminated at the time of head down. SOLUTION: When a ribbon save function is released and a thermal head 25 is touched to a sheet P, a motor 49 on the ribbon winding side is fed with a voltage Vr+α which is higher than a voltage Vr for generating a winding force suitable to the diameter of a thermal transfer ribbon. Subsequently, the voltage being fed to the motor 49 is lowered to the level Vr for generating a winding force suitable to the diameter of the thermal transfer ribbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer such as a label printer for printing a bar code or other contents on a tag or a label.

[0002]

2. Description of the Related Art A thermal transfer printer such as a label printer for printing a barcode on a tag or a label using a ribbon is widely used. In such a thermal transfer printer, the ribbon is transported so that the ribbon passes between the thermal head and a printed material such as a tag and a label. That is, the ribbon is transported from the ribbon supply side to the ribbon winding side.

Some thermal transfer printers have a ribbon save function for saving the ribbon by not transporting the ribbon while the printing operation is not being performed.

[0004] The ribbon save function will be described.

[0005] As shown in FIG. 8, a case where there is one unit printing will be described. The description will be made on the assumption that the printing areas to be printed are separated from each other during the one-unit printing, that is, there is a printing pattern in which the printing area D and the printing area E are separated. In such a case, the ribbon is wasted between the printing unit D and the printing unit E, and the ribbon is advanced because the ribbon advances between the head and the sheet. To prevent this,
Between the print area D and the print area E, the head is separated from the paper, the driving of the ribbon is stopped, and only the paper is conveyed, thereby saving the ribbon.

As shown in FIG. 8, when the paper in the direction C is being conveyed, the head is raised and separated from the paper immediately after the printing of the print area D is completed, and the driving of the ribbon is stopped. Next, the head is lowered again at a position slightly downstream of the print area E, and printing is performed. Thus, the ribbon can be saved between the print area D and the print area E by raising the head. The raising / lowering of the head is usually performed by controlling the energization of a normal solenoid (not shown) in many cases.

[0007]

In such an operation, conventional control will be described with reference to FIG. Note that the solenoid here is described on the condition that a self-holding solenoid is used. The self-holding solenoid is a solenoid that keeps its posture after sending a certain voltage in a pulsed manner for a certain period of time in the adsorption and release of the iron core of the solenoid, and thereafter without energizing. For example, the iron core is released when the iron core is in the suction state. When a certain voltage is sent for a certain period of time in a pulsed state, the iron core is released and becomes free. Conversely, when trying to attract, if the voltage is sent in a pulsed form for a certain period of time, the state becomes the attracting state, and even if the energization ends, the attracting state is maintained until the energizing for release comes. .

When print data is transmitted to the printer,
The voltage Vs applied to the solenoid in the suction state (head-up state) at a predetermined time before the start of printing is changed to Ts (ms).
By energizing only for a time ec), the adsorption state of the solenoid is released. As a result, the head goes down, and a printable state is set.

The voltage on the winding side of the ribbon is synchronized with the voltage Vr according to the ribbon diameter in synchronization with the start of energization of the solenoid.
To the DC motor to rotate the ribbon. Note that the voltage V
Before applying r to the DC motor, a slight voltage Vo is applied to slightly stretch the ribbon. When doing so, there were the following problems. That is, a certain appropriate voltage applied to the DC motor is, as described above, when the head is pressed by a certain force on the paper via the ribbon to perform printing, that is, the ribbon is sandwiched between the head and the paper. This is the voltage at which proper tension is applied to obtain proper printing when the printing speed matches the paper speed.
Therefore, when the head falls and the ribbon is pressed against the paper, a slight resistance is generated, and the ribbon speed becomes slower than the paper speed, resulting in a relative speed difference, and the ink of the ribbon appears on the paper near the head down portion. (Hereinafter, this phenomenon is referred to as smudge).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a thermal transfer printer capable of eliminating the occurrence of smudge when a head is down.

[0011]

According to a first aspect of the present invention, there is provided a thermal transfer printer for generating a winding force of the thermal transfer ribbon to a winding mechanism for winding the thermal transfer ribbon.
A second motor that generates a back tension force in a direction opposite to a winding force of the thermal transfer ribbon to a ribbon supply mechanism that supplies the thermal transfer ribbon;
The drive of the first motor is controlled so as to generate a winding force suitable for the ribbon diameter of the thermal transfer ribbon wound by the winding mechanism, and the ribbon of the thermal transfer ribbon wound by the ribbon supply mechanism is controlled. Motor drive control means for controlling the driving of the second motor so as to generate a back tension force suitable for the diameter; and, in an area where there is no print data by the thermal head, the thermal head is separated from the print medium to print the medium. In a thermal transfer printer equipped with a ribbon save function that does not wind and supply the thermal transfer ribbon, the motor drive control means cancels the ribbon save function, and the thermal head contacts the print medium. When contacting, the first motor is higher than a winding force suitable for the ribbon diameter of the thermal transfer ribbon. Driven by come-up force, and wherein the lowering thereafter the winding force suitable for ribbon diameter of the thermal transfer ribbon.

According to a second aspect of the present invention, in the thermal transfer printer according to the first aspect, the first motor is controlled before the thermal head is brought into contact with a print medium by releasing the ribbon save function. The take-up force of the first motor is gradually increased by a plurality of steps. When the thermal head is brought into contact with the print medium, the take-up force of the first motor is adjusted to a take-up force suitable for the ribbon diameter of the thermal transfer ribbon. And a winding force suitable for the ribbon diameter of the thermal transfer ribbon.

According to a third aspect of the present invention, in the thermal transfer printer according to the first aspect of the present invention, the motor drive voltage control means is configured to release the ribbon save function from the first position before the thermal head comes into contact with a print medium. The winding force of the motor is gradually increased by a plurality of steps, and when the thermal head is brought into contact with the printing medium, the winding force of the first motor is adjusted to a winding diameter suitable for the ribbon diameter of the thermal transfer ribbon. While the winding force is higher than the winding force, the second
The back tension force supplied to the motor is varied from the back tension force suitable for the ribbon diameter of the thermal transfer ribbon wound on the ribbon supply mechanism, and then the first motor and the second motor are respectively driven. It is characterized in that a winding force suitable for the ribbon diameter of the thermal transfer ribbon is generated.

According to a fourth aspect of the present invention, there is provided a thermal transfer printer wherein the winding force supplied to the first motor is gradually increased in a plurality of steps, and the winding power is supplied to the first motor. A winding force higher than a winding force suitable for the ribbon diameter of the thermal transfer ribbon and a back tension force varied from a back tension force suitable for the ribbon diameter of the thermal transfer ribbon supplied to the second motor can be arbitrarily set. It is characterized by the following.

According to a fifth aspect of the present invention, the set winding force and the back tension force according to the fourth aspect are stored in a storage unit for each type of the thermal transfer ribbon. The power supplied to the first motor and the second motor is controlled based on the set winding force and back tension force corresponding to the thermal transfer ribbon.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a thermal transfer printer according to the present invention. In FIG. 1, reference numeral 11 denotes a housing of the thermal transfer printer. On the back of this case 11,
A paper supply unit 12 in which the continuous paper P is wound is provided. Further, a liquid crystal display unit 13 and a switch unit 14 are provided on a front surface of the housing 11. Reference numeral 15 denotes a discharge port from which the printed continuous paper P is discharged.

Incidentally, the housing 11 is provided with a plurality of sets of thermal heads and platens so as to face each other along a transport path on which the continuous paper P is transported. Further, a ribbon is supplied between each set of thermal heads and the continuous paper P.

Next, referring to FIG. 2, the internal configuration of the thermal transfer printer will be briefly described by taking one of a plurality of sets of thermal head and platen as an example. In FIG. 2, a drive roller 22 is provided on the upstream side of a transport path 21 immediately downstream of the paper supply unit 12, and a pinch roller 23 is provided to face the drive roller 22. Reference numeral 24 denotes a paper sensor for detecting the leading edge of the paper.

Reference numeral 25 denotes a thermal head. A platen 26 is provided to face the thermal head 25. The thermal head 25 is moved by a mechanism to be described later into a head down position where the thermal head 25 comes into contact with the platen 26,
The position can be switched to a head-up position separated from the platen 26.

A ribbon 27 is supplied between the thermal head 25 and the continuous paper P. The ribbon 27 is wound around a supply roller 28, and the ribbon 27 supplied from the supply roller 28 is taken up by a winding roller 29.
It is wound up. The rotation of the supply roller 28 is controlled by a ribbon supply motor described later, and the rotation of the winding roller 29 is controlled by a ribbon winding motor described later.

Next, a control block diagram of a control circuit for controlling the thermal transfer printer will be described with reference to FIG. In this embodiment, an example in which two thermal heads (a first print head and a second print head) are mounted in a housing 11 will be described.

In FIG. 3, reference numeral 31 denotes a CPU (central processing unit) for controlling the thermal transfer printer. This CPU3
A ROM (Read Only Memory) 32 in which various control programs are stored,
A switch unit 14 via a RAM (random access memory) 33 as a storage means and an I / O port 34;
A supply-side ribbon diameter detection unit 35 for detecting the diameter of the ribbon wound around the supply-side roller 28, a winding-side ribbon diameter detection unit 36 for detecting the diameter of the ribbon wound by the winding-side roller 29, are externally connected. A communication interface 37 for transmitting and receiving data to and from a personal computer (PC) is connected. Here, the RAM 33 stores, for each type of ribbon, a voltage Vr to be applied to the ribbon take-up motor 49 suitable for the diameter of the ribbon wound around the take-up roller 29 and the ribbon wound around the supply-side roller 28. A memory 33m in which various data such as α (V), β (V), θ (V), η (V) and the like to be described later are stored in addition to the voltage Vb applied to the ribbon supply side motor 47 suitable for the diameter. Is provided.

Further, the system bus 31a has a first print control unit 42 for controlling power supply to the first print head 41 and a second print control unit for controlling power supply to the second print head 43. 44, a first head mechanism unit 4 for performing head-up / head-down of the first print head 41
5, a second head mechanism section 46 for performing head-up / head-down of the second print head 43, and a supply-side roller 28
Motor driver 4 that controls the drive voltage supplied by the ribbon supply motor (second motor) 47 that drives the
8. A take-up motor driver 50 that controls a drive voltage supplied to a ribbon take-up motor (first motor) 49 that drives the take-up roller 29, and a motor that controls rotation of the drive roller 22 and the pinch roller 23. A first motor driver 52 for controlling a motor 51; a second motor driver 5 for controlling a motor 53 for controlling the rotation of the platen 26;
4 are connected. Here, the ribbon take-up side motor (first motor) 49 and the ribbon supply side motor (second motor) 47 are DC motors.

The motor driver 48 is constituted by the motor driver 48 on the supply side and the motor driver 50 on the winding side.

Next, a ribbon winding mechanism will be described with reference to FIG. As shown in FIG. 4A, a motor gear 60, an idler gear 61, and a final-stage winding gear 62 are attached to the ribbon winding-side motor 49. The take-up gear 62 is provided integrally with the end of the take-up roller 29 that holds the take-up ribbon. The winding gear 62 is provided with slits 71 periodically along the circumferential direction. Further, a transmission sensor 72 as the winding-side ribbon diameter detection unit 36 is provided so as to sandwich the winding gear 62 through which the slit 71 passes. The transmission sensor 72 detects light through the slit 71 to detect the angular velocity of the take-up gear 62, and from the angular velocity, the diameter of the ribbon wound around the take-up roller 29.

FIG. 4A shows a ribbon take-up mechanism. The ribbon supply mechanism has a structure in which an idler gear 61 is removed and a motor gear 60 and a take-up gear 62 are directly meshed. It has become.
The diameter of the ribbon wound on the supply roller 28 in the ribbon supply mechanism is detected by a supply ribbon diameter detection unit 35.

Next, a specific ribbon control will be described with reference to FIG. Generally, such a thermal transfer ribbon is a thin film-like sheet. Accordingly, wrinkles are likely to occur on the ribbon, and these wrinkles adversely affect printing. It is common sense to apply a certain tension to prevent this. When the tension is too weak, wrinkles are generated. On the contrary, when the tension is too strong, the ribbon breaks. Therefore, a predetermined tension must be applied. Further, the tension force is generated by applying a winding force F1 and a back tension force F2 as shown in FIG. F1 is determined by the voltage of the ribbon winding side motor 49, in other words, the output torque of the motor 49 and the ribbon diameter at that time.

The back tension force F2 is determined as follows. A voltage is applied to the ribbon supply motor 47 connected to the supply roller 28 so that the ribbon supply motor 47 rotates in the direction opposite to the direction in which the ribbon rotates, that is, in the direction B. When printing is started and the ribbon is about to be wound, the ribbon on the supply side advances against the force of the ribbon supply side motor 47 to rotate. At this time, a back tension force F2 is generated. The tension force is a state where it is desirable that the tension force be a certain appropriate force and be constant. It should be noted that the proper force and, since coming each different by the paper to be ribbons and printed Arajime how much force is determined by the good or test and the like.

By the way, the diameter of the ribbon wound around the take-up roller 29 increases as printing progresses, and the diameter of the ribbon of the supply roller 28 decreases.

Therefore, when a constant voltage is applied to the ribbon winding side motor 49, the same torque is generated, so that the values of F1 and F2 differ depending on the ribbon diameter. As described above, it is desirable that the ribbon tension force is constant. That is, even if the ribbon diameter changes, the ribbon tension force will be constant if F1 and F2 are always kept constant. In order to keep F1 and F2 constant,
A ribbon diameter is detected, and a voltage applied to the ribbon winding-side motor 49 and the ribbon supply-side motor 47 is adjusted so that the ribbon diameters become F1 and F2.
0, control may be performed by the supply-side motor driver 48.

That is, if the diameter of the ribbon wound on the take-up roller 29 and the ribbon of the supply roller 28 are known, the voltage Vr and the voltage Vb set in the memory 33m are calculated.
By outputting the signals to the ribbon winding side motor (first motor) 49 and the ribbon supply side motor (second motor) 47, constant F1 and F2 forces can be realized.

Referring now to FIG. 6, a schematic diagram of a head-up mechanism employed in both the first head mechanism 45 and the second head mechanism 46 will be described. As shown in FIG. 6, a transmission plate 82 is provided to support a head fulcrum shaft 81 attached to the thermal head 25 via a metal plate or the like.
The transmission plate 82 is pivoted about the fulcrum 83 by the operation of the solenoid 84 to move the thermal head 25 up and down.

That is, the ribbon is started to be driven before the head down (solenoid release) signal, and when a short time has passed after the head down signal is output, the ribbon winding side motor (first motor) 49 By applying a voltage slightly higher than the appropriate set voltage Vr for the diameter, at the moment when the head drops on the paper, the speed of the ribbon is slightly faster than the conventional set voltage, so that the moment when the head drops slightly Speed difference between paper and ribbon.

Next, the operation will be described with reference to FIG. When the print data is transmitted from the externally connected personal computer, the take-up motor driver 50 starts printing the print data on the paper T (m
sec) Before, first, an appropriate winding side voltage Vr (V) for the diameter of the ribbon is obtained from the memory 33m.
One-third of a voltage obtained by subtracting a slight voltage β (V) from the voltage Vr is applied to the ribbon winding side motor 49 by Tβ1 (msec).

Next, the take-up motor driver 50 applies a voltage of 2/3 of (Vr-β) to the ribbon take-up motor 49 for Tβ2 (msec).

Further, the take-up motor driver 50 applies the voltage (Vr-β) to the ribbon take-up motor 49 for Tβ3 (msec).

When the voltage applied to the ribbon winding side motor 49 is Vr-β (V), the first head mechanism 45 or the second head mechanism 46
A solenoid release signal (head down signal) is output. Then, while the head is down, the voltage applied to the ribbon winding side motor 49 is set to a voltage obtained by adding α (V) from the appropriate voltage Vr (V) of the ribbon diameter at that time. Then, when a short period of time has elapsed after the head is completely down, an appropriate voltage Vr (V) corresponding to the ribbon diameter is set.

With this arrangement, when the head goes down on the sheet, the speed difference between the ribbon and the sheet due to the resistance is turned at a speed slightly higher than the appropriate voltage Vr (V), but the head drops. Vr (V) as if by resistance at the time
Because it advances at the same speed as the paper, in other words, at the same speed as the paper,
The smudge when the head under the conventional control goes down can be eliminated. Here, α ≧ 0 and β ≧ 0. By increasing the voltage applied to the ribbon winding side motor 49 in a stepwise manner, the winding side roller 29 is gradually rotated to prevent waste of the ribbon.

As described above, when the head goes down on the paper, the speed difference between the ribbon and the paper due to the resistance is determined by the appropriate voltage V
It is trying to rotate at a speed slightly faster than r (V), but because of the resistance when the head falls, it proceeds at the same speed as Vr (V), in other words, at the same speed as the paper. The smudge when the head goes down can be eliminated.

Further, the above is the ribbon winding side motor 4
Although the case where the voltage applied to 9 is controlled has been described,
The voltage supplied to the ribbon supply side motor 47 is shown in FIG.
As shown in (2), the voltage is slightly adjusted (Vr + θ, Vr−η) from the voltage Vb (V) suitable for the ribbon diameter, and the above α,
The effect can be further enhanced by combining β. Here, θ ≧ 0 and η ≧ 0.

There are various types of ribbons used in thermal transfer printers. Depending on the characteristics of the ribbon, some types of smudges are easy to come out and others are hard to come out.Therefore, if the user can adjust the related numerical value according to the ribbon so that it can respond to the ribbon, it can be used for a wide range of ribbons Becomes Therefore, the memory 33m
Then, the determined numerical value is stored for each ribbon, and, for example, by selecting the ribbon with printer driver software on an externally connected PC, control of the set value is executed in the printer, and When using a ribbon, optimal ribbon control can be performed.

The voltage Vr set in the memory 33m,
Various data such as voltage Vb, α (V), β (V), θ (V), η (V) are stored in a PC externally connected to the thermal transfer printer.
The user may set this from.

In the above embodiment, an example of a printer in which two thermal heads (a first print head and a second print head) are mounted in the housing 11 has been described, but only one thermal head is provided. The same can be said for a device having three or more thermal heads.

The motor 47 on the ribbon supply side and the motor 49 on the winding side are not limited to DC motors, but may be any motors capable of controlling torque.

[0045]

As described in detail above, according to the present invention,
It is possible to provide a thermal transfer printer capable of eliminating generation of smudge when the head is down.

[Brief description of the drawings]

FIG. 1 is a perspective view of a thermal transfer printer according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a main part in the thermal transfer printer.

FIG. 3 is a control block diagram of the thermal transfer printer.

FIG. 4 is a diagram schematically showing a ribbon driving unit.

FIG. 5 is a diagram for explaining ribbon control.

FIG. 6 is a diagram showing a head-up mechanism.

FIG. 7 is a waveform chart for explaining the operation of the embodiment.

FIG. 8 is a diagram illustrating a ribbon save function.

FIG. 9 is a waveform chart for explaining conventional control.

[Explanation of symbols]

 31 CPU, 32 ROM, 33 RAM (Random Access Memory) 35 Supply Ribbon Diameter Detector, 36 Winding Ribbon Diameter Detector, 41 First Print Head, 42 First Print control unit 43: second print head 44: second print control unit 45: first head mechanism unit 46: second head mechanism unit 47: ribbon supply side motor 48: supply side Motor driver 49: ribbon winding side motor 50: winding side motor driver 51: first motor 52: first motor driver 54: second motor driver

Continued on the front page F term (reference) 2C064 CC02 CC06 EE01 EE06 FF03 FF07 2C065 AA01 AB03 AC04 AD02 DA12 DA17 DA20 DA22 2C068 AA02 AA06 GH02

Claims (5)

[Claims] A first motor for generating a winding force of the thermal transfer ribbon for a winding mechanism for winding the thermal transfer ribbon; and a winding of the thermal transfer ribbon for a ribbon supply mechanism for supplying the thermal transfer ribbon. A second motor for generating a back tension force in a direction opposite to a take-up force, and the first motor for generating a take-up force suitable for a ribbon diameter of the thermal transfer ribbon taken up by the take-up mechanism. Drive control means for controlling the driving of the second motor and controlling the driving of the second motor so as to generate a back tension force suitable for the ribbon diameter of the thermal transfer ribbon wound on the ribbon supply mechanism; and the thermal head In areas where there is no print data,
In a thermal transfer printer having a ribbon save function in which the thermal head is separated from a print medium to convey the print medium and does not perform winding and supply of the thermal transfer ribbon, the motor drive control means includes a ribbon save function. When the thermal head is released and the thermal head comes into contact with the print medium, the first motor is driven with a winding force higher than a winding force suitable for the ribbon diameter of the thermal transfer ribbon. A thermal transfer printer characterized by lowering the take-up force suitable for the ribbon diameter. 2. The motor drive control means gradually reduces the winding force of the first motor by a plurality of steps before the ribbon save function is released and before the thermal head comes into contact with a print medium. When the thermal head is brought into contact with a printing medium, the winding force of the first motor is set to a winding force higher than the winding force suitable for the ribbon diameter of the thermal transfer ribbon. 2. The thermal transfer printer according to claim 1, wherein a winding force suitable for a diameter of the thermal transfer ribbon is set. 3. The motor drive control means gradually reduces the winding force of the first motor by a plurality of steps before the ribbon save function is released and before the thermal head comes into contact with a print medium. When the thermal head is brought into contact with a print medium, the first motor is wound up while the winding force is higher than the winding force suitable for the ribbon diameter of the thermal transfer ribbon. The back tension force supplied to the second motor is changed from a back tension force suitable for a ribbon diameter of the thermal transfer ribbon wound on the ribbon supply mechanism, and thereafter, the first motor and the second motor are rotated. 2. The thermal transfer printer according to claim 1, wherein the motor generates a winding force suitable for the diameter of the thermal transfer ribbon. 4. A winding force increasing mode in which the winding force supplied to the first motor is gradually increased in a plurality of steps, and a winding force suitable for a ribbon diameter of the thermal transfer ribbon supplied to the first motor. The thermal transfer according to claim 3, wherein a back tension force that varies from a higher take-up force and a back tension force suitable for a ribbon diameter of the thermal transfer ribbon supplied to the second motor can be arbitrarily set. Printer. 5. The set winding force and back tension force are stored in storage means for each type of thermal transfer ribbon, and the motor drive control means sets the winding force corresponding to the set thermal transfer ribbon. 5. The thermal transfer printer according to claim 4, wherein the power supplied to the first motor and the second motor is controlled based on the back tension force.