JP2007118536A - Thermal transfer printer and motor control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein the movement of an ink ribbon is delayed than paper, at the start of printing, thereby makes the paper stained with ink, makes wrinkles appear in the ink ribbon, and makes the ink ribbon cut. <P>SOLUTION: This thermal transfer printer, which makes printing on the paper 15 via the ink ribbon 10 by a print head 11 while carrying the paper 15, comprises ink ribbon motors M1 and M2 for carrying the ink ribbon 10, and a stepping motor 13 for carrying the paper 15. The thermal transfer printer has a control means 21 for starting the drive of the ink ribbon motors M1 and M2 a predetermined time before the start of the drive of the stepping motor 13, at the start of the printing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal transfer printer using an ink ribbon and a motor control method for the thermal transfer printer.

  In Patent Document 1, in a transfer type printer that conveys ink ribbon and paper in the same direction and prints predetermined print information on the paper by a thermal head, a stepping motor as a control motor for carrying the paper, A DC motor for transporting the ink ribbon, drive setting means for setting the drive amount or drive time of the stepping motor at the time of printing based on the print information and the like, and the stepping motor at the time of printing by the drive setting means Control motor drive means for driving the set drive amount or drive time, and energization to the DC motor is started simultaneously with the start of driving of the stepping motor by the control motor drive means, and the drive amount set by the drive means Or drive amount or drive time obtained by subtracting preset drive amount or time from drive time Serial The transfer type printer provided with a DC motor current control means for stopping power supply to the DC motor is described when driving the stepping motor.

Japanese Patent No. 3034128

  The transfer type printer described in Patent Document 1 has a DC motor for transporting an ink ribbon and a stepping motor for transporting paper, and relates to the operation of the stepping motor at the start and stop of printing. . In this transfer type printer, at the time of start-up, the paper transport motor and the stepping motor are driven at the same time, but the direct current motor for transporting the ink ribbon and the stepping motor for transporting the paper are: Even if they are driven simultaneously, they do not operate simultaneously due to differences in motor characteristics (motor type), and the DC motor operates later than the stepping motor. For this reason, since the paper moves first and then the ink ribbon moves, ink stain (smudge) on the paper, ink ribbon wrinkles, and ink ribbon breakage may occur.

The difference in operation start time due to the difference in motor type between the DC motor for transporting the ink ribbon and the stepping motor for transporting the paper is as follows.
A stepping motor used for paper conveyance can be driven at a frequency below the self-starting frequency of the motor. The self-starting frequency of the stepping motor of the thermal transfer printer exceeds, for example, 2 KHz. Therefore, the operation frequency of the paper transporting stepping motor when the paper transport is started is set to 2 KHz, for example. Accordingly, the sheet transporting stepping motor starts to move at least at 2 KHz or more. In other words, it takes a shorter time than 0.5 milliseconds for the paper transporting stepping motor to start moving after the paper transporting stepping motor is energized.

  However, a DC motor for transporting an ink ribbon has a large electrical time constant and mechanical time constant (such as those caused by an inertial load such as the DC motor itself and an ink ribbon) even when a current is passed. I can't start spinning. Further, the shaft of the reel around which the ink ribbon is wound is not directly operated by a direct current motor but is driven through a two-stage or three-stage gear. For this reason, the shaft of the reel around which the ink ribbon is wound also causes a delay in operation transmission due to gear backlash.

  FIG. 2 is a diagram showing a behavior (relation between a motor start time and a printing speed (hereinafter also referred to as a printing speed)) at the time of driving a paper conveying stepping motor and a DC motor for conveying an ink ribbon. As shown in FIG. 2, the paper transporting stepping motor can rotate at a predetermined rotational speed immediately after being instructed to rotate (drive) below the self-starting frequency. The speed becomes 2 ″ / s. Thereafter, the sheet conveying stepping motor gradually increases the rotational speed to reach the maximum speed of 12 ″ / s.

On the other hand, the direct current motor for transporting the ink ribbon does not start rotating immediately after being driven. Therefore, as shown in FIG. The speed goes up.
As described above, even when the paper transporting stepping motor starts rotating, the DC motor for transporting the ink ribbon does not start rotating, so that the ink ribbon sags, the ink ribbon wrinkles or the ink ribbon wrinkles. There is a problem that the rubbing trace remains on the paper.

  In general, in a thermal transfer printer, the paper conveyance speed (printing speed) can be arbitrarily changed according to the type of supply and the user's request. When the paper transport speed changes, the driving speed of the paper transport stepping motor and the DC motor for transporting the ink ribbon becomes an acceleration curve (acceleration profile) corresponding to the paper transport speed, and the acceleration time The acceleration (acceleration profile) is set so as to be optimal for each sheet conveyance speed (see FIG. 4).

  Therefore, if the speed control of the DC motor for transporting the ink ribbon is always performed in the same manner regardless of the paper transport speed, the rotation control of the stepping motor and the DC motor is optimal control at a certain paper transport speed. Even if the paper transport speed is different from that, the ink ribbon cannot be fed out properly, the ink ribbon may sag, or excessive tension is applied to the ink ribbon, and the ink ribbon may become smudged. There arises a problem that a wrinkle occurs, a rubbing trace of the ink ribbon remains on the paper, or the ink ribbon is cut. In particular, high-speed thermal transfer printers with greatly different paper transport speeds have a large difference in paper transport speed. For example, the paper transport speed can be varied from 2 "/ s to 12" / s. A control method suitable for all paper conveyance speeds cannot be adopted.

The present invention can feed the ink ribbon following the paper without delay in paper conveyance at the start of printing at all paper conveyance speeds, can generate an appropriate tension on the ink ribbon, It is an object of the present invention to provide a thermal transfer printer and a motor control method for the thermal transfer printer that can suppress the occurrence of smudge), ink ribbon wrinkles, and ink ribbon breakage.
Another object of the present invention is to provide a thermal transfer printer capable of suppressing the occurrence of ink smudges (smudge), ink ribbon wrinkles, and ink ribbon breakage regardless of the type of ink ribbon. For the purpose.

  In order to achieve the above object, an invention according to claim 1 is directed to an ink ribbon motor for transporting the ink ribbon in a thermal transfer printer that transports the paper and prints on the paper through an ink ribbon on the paper. And a stepping motor for transporting the paper, and has a control means for starting the driving of the ink ribbon motor at a predetermined time before starting the driving of the stepping motor at the start of printing.

  According to a second aspect of the present invention, in the thermal transfer printer according to the first aspect, the control means controls the speed of the ink ribbon motor following the conveyance acceleration of the paper after the driving of the ink ribbon motor is started. Is.

  According to a third aspect of the present invention, in the thermal transfer printer according to the second aspect of the present invention, the thermal transfer printer includes a control table that indicates a relationship between the conveyance acceleration of the paper after the start of driving the ink ribbon motor and the speed of the ink ribbon motor, The control means controls the speed of the ink ribbon motor with reference to the control table according to the transport speed of the paper.

  According to a fourth aspect of the present invention, in the thermal transfer printer according to the third aspect, a function of adding or subtracting a constant value to the control table according to an instruction from the outside is provided.

  The invention according to claim 5 is the thermal transfer printer according to claim 3 or 4, wherein the control table includes a plurality of control tables, and the plurality of control tables are selected according to the ink ribbon to be used. It comprises.

  The invention according to claim 6 includes an ink ribbon motor for transporting an ink ribbon and a stepping motor for transporting the paper, and transports the paper to the paper via the ink ribbon by the print head. In the motor control method of the thermal transfer printer that performs printing, the driving of the ink ribbon motor is started at a predetermined time before the start of driving of the stepping motor at the start of printing.

According to the present invention, the ink ribbon can be fed following the paper without delaying the paper conveyance at the start of printing at all paper conveyance speeds, and an appropriate tension can be generated on the ink ribbon. Smudge, ink ribbon wrinkles, and ink ribbon breakage can be suppressed.
According to the present invention, it is possible to suppress the occurrence of ink stains (smudge), ink ribbon wrinkles, and ink ribbon breakage regardless of the type of ink ribbon.

  FIG. 1 shows a thermal transfer printer according to an embodiment of the present invention. In this thermal transfer printer, when the ink ribbon 10 is set, the ink ribbon 10 is wound around the supply-side reel r2 as the ink ribbon supply member, and the leading end side of the thermal head 11 as the print head is used. And the platen 12 are wound around a take-up reel r1 as an ink ribbon take-up member. An ink ribbon supply DC motor and an ink ribbon winding DC motor are connected to the shafts of the supply reel r2 and the take-up reel r1 through gears, respectively. Although not shown, the ink ribbon supply DC motor and the ink ribbon winding DC motor are the ink ribbon supply DC motor M1 and the ink ribbon winding DC motor M2. The platen 12 is connected to a paper transport motor 13, and a roll paper 15 as a paper wound around a reel 14 is passed between the thermal head 11 and the platen 12 so as to overlap the ink ribbon 10.

  During printing, the ink ribbon 10 is driven to rotate in the direction indicated by the arrow T2 by the supply ribbon r2 by the ink ribbon supply DC motor M1, and the take-up reel r1 by the ink ribbon winding DC motor M2. It travels between the thermal head 11 and the platen 12 by being rotationally driven in the direction of T1. The platen 12 is rotationally driven by the paper transport motor 13 so that the paper 15 travels between the thermal head 11 and the platen 12 at the same speed in the same direction as the ink ribbon 10, and the plurality of heating elements of the thermal head 11 are moved. By generating heat according to the image data, the ink on the ink ribbon 10 is melted and transferred to the paper 15, so that an image is printed on the paper 15.

  FIG. 9 shows the electrical configuration of the printer. The printer includes a main control unit (CPU) 21 as control means, a RAM 22 used as a work area, a ROM 23 storing programs and data, an operation unit 24, an external interface (I / F) unit 25, and a thermal head 11. A print control unit 26 as a control means for controlling the ink ribbon, a ribbon winding motor driver 27 for driving the ink ribbon winding DC motor M2, a ribbon supply motor driver 28 for driving the ink ribbon supplying DC motor M1, and a paper transport motor. 13, a paper transport motor driver 29 for driving 13, various paper sensor input units 30 for inputting input signals from various paper sensors 31 of the printer to the main control unit 21, and the like.

  The main control unit 21 controls the thermal head 11 via the print control unit 26, and the ink ribbon winding DC motor M <b> 2, the ink ribbon supply DC motor M <b> 1, and the paper transport motor 13 via the motor drivers 27 to 29. To control. The main control unit 21 takes in an input signal from the operation unit 24 and performs various display controls of the operation unit 24. The main control unit 21 takes in image data from the outside via the external I / F unit 25 and sends the image data to the thermal head 11 via the print control unit 26, and the plurality of heating elements of the thermal head 11 are transferred to the image data. In response to this, the ink on the ink ribbon 10 is melted and transferred to the paper 15 by generating heat. Also, the main control unit 21 uses a control table 32 stored in the ROM 23 to pass the ink ribbon winding DC motor M2 and the ink ribbon supply DC motor via the motor drivers 27 to 29 as will be described later. M1 and the paper transport motor 13 are controlled.

  FIG. 10 shows the configuration of a DC motor driver. The motor drivers 27 and 28 are the motor drivers shown in FIG. The motor driver includes an IC control unit 33, a constant current control unit 34, and a drive unit 35 using transistors Q1 to Q4. The IC control unit 33 turns the drive unit 35 on and off according to an operation instruction from the main control unit 21 to turn on and off the drive of the motors M1 and M2, and causes the drive unit 35 to respond to a rotation direction instruction from the main control unit 21. The motors M1 and M2 are driven clockwise or counterclockwise. The constant current control unit 34 causes the drive unit 35 to drive the motors M <b> 1 and M <b> 2 with the commanded current value according to the current value command from the main control unit 21. The drive unit 35 drives the motors M1 and M2 based on output signals from the IC control unit 33 and the constant current control unit 34.

  The main control unit 21 determines the behavior (start of rotation) of the ink ribbon motor (the ink ribbon winding DC motor M2 and the ink ribbon supply DC motor M1) and the paper transport motor with respect to the motor drivers 27 to 29 at the start of printing. The ink ribbon motors M1 and M2 are started to be driven a predetermined time before the start of the driving of the stepping motor 13 so that the behavior (start of rotation) of the stepping motor 13 becomes the same. 3 shows the start of driving of the ink ribbon motors M1 and M2 with respect to the startup characteristics (relationship between startup time and printing speed) of the ink ribbon motors M2 and M1 and the paper transport motor 13 shown in FIG. The starting characteristics (starting time and start time) of the ink ribbon motors M1 and M2 and the paper transport motor 13 when starting earlier than the drive of the paper transport motor 13 are set so that the behavior of the M1 and the paper transport motor 13 is the same. (Relationship with printing speed).

As can be seen from FIG. 3, the driving of the ink ribbon motors M1 and M2 is started earlier than the driving of the paper transport motor 13 so that the behavior of the ink ribbon motors M1 and M2 and the behavior of the paper transport motor 13 are the same. In this case, when the paper transport motor 13 starts rotating, the ink ribbon motors M1 and M2 start rotating without delaying the operation of the paper transport motor 13.
FIG. 4 shows acceleration profiles (relationships between the startup time of the ink ribbon motors M2 and M1 and the printing speed) for printing speeds 12 ips, 10 ips, 8 ips, 6 ips, 4 ips, and 2 ips at the start of paper conveyance of the printer. It can be seen from FIG. 4 that the acceleration (profile) at the start of paper conveyance of the ink ribbon motors M1 and M2 differs for each printing speed.

  On the other hand, FIG. 5 shows values of currents that flow through the ink ribbon motors M1 and M2 in a state where a constant load is applied to the ink ribbon motors M1 and M2 in a real machine state (a constant tension is applied to the ink ribbon 10). The starting characteristics A to G when changing is shown. The drive current values of the ink ribbon motors M1 and M2 decrease from the start characteristic A to the start characteristic G.

In this printer, the main control unit 21 follows the paper conveyance acceleration when accelerating the paper conveyance speed after the operation of the ink ribbon winding DC motor M2 and the ink ribbon supply DC motor M1 is started. The acceleration profiles of the ink ribbon motors M1 and M2 are obtained by controlling the speeds of the ribbon winding DC motor M2 and the ink ribbon supply DC motor M1, and the acceleration profiles are stored in the control table 32. explain.
From FIG. 4, it can be seen that the acceleration (acceleration profile) at the start of paper conveyance of the ink ribbon motors M1 and M2 differs for each printing speed (paper conveyance speed). Here, for example, a case where the paper conveyance speed is 8 ″ / s will be described. FIG. 6 illustrates the case where the paper conveyance motor 13 is set to ink with respect to the start characteristics A to G of the ink ribbon motors M1 and M2 illustrated in FIG. The acceleration profile H at the paper conveyance speed of 8 ″ / s when driven simultaneously with the ribbon motors M1 and M2 is shown superimposed. FIG. 7 shows the activation of the sheet conveyance motor 13 when the main control unit 21 delays the operation start time of the sheet conveyance motor 13 for each of the motor drivers 27 to 29 by 8 ms compared with the operation start times of the ink ribbon motors M1 and M2. The characteristics and the starting characteristics of the ink ribbon motors M1 and M2 are shown in an overlapping manner. From FIG. 7, there is a section A in which the paper conveyance characteristic curve (characteristic of the paper conveyance motor 13) H coincides with the characteristic curve when the ink ribbon motors M1 and M2 are driven with the current value I.

  In this section A, the start characteristics of the paper transport motor 13 and the start characteristics of the ink ribbon motors M1 and M2 coincide with each other. In this section A, if the ink ribbon motors M1 and M2 are driven with the current value I, Thus, the ink ribbon 10 can be sent out at the same speed as the paper conveyance speed. In the section A, the sheet conveyance characteristic curve (starting characteristic of the sheet conveying motor 13) and the starting characteristics of the ink ribbon motors M1 and M2 coincide with each other up to the printing speed of 0.75 "/ s. 7 to search for a point where the sheet conveyance speed characteristic curve matches the characteristic curve of the ink ribbon motors M1 and M2 when a certain value of current is passed through the ink ribbon motors M1 and M2. The time axis (paper conveyance characteristic curve) is shifted and recorded in FIG.

The result is shown in FIG. In FIG. 8, during the section B (from the paper transport speed 0.75 ″ / s to the paper transport speed 1.25 ″ / s), the paper transport speed characteristic curve (starting characteristic of the paper transport motor 13) and the ink ribbon motor M1 are illustrated. , M2 coincides with the starting characteristics. Therefore, the ink ribbon motors M1 and M2 may be driven by the current J from the paper transport speed 0.75 "/ s to the paper transport speed 1.25" / s. Therefore, the main control unit 21 controls the ink ribbon motors M1 and M2 with respect to the motor drivers 27 and 28 as follows before operating the paper transport motor 13 (before starting printing).
(1) The ink ribbon motors M1 and M2 are 8 ms from the start of driving of the paper transport motor 13 so that the behavior (start of rotation) of the ink ribbon motors M1 and M2 and the behavior of the paper transport motor 13 (start of rotation) are the same. The driving is started at the current value I before.
(2) The current values of the ink ribbon motors M1 and M2 are set so that the sheet conveyance speed characteristic curve (starting characteristic of the sheet conveying motor 13) coincides with the starting characteristics of the ink ribbon motors M1 and M2 when 13 ms has elapsed from the start of driving. Is J.
(3) The ink ribbon motors M1 and M2 are driven for 5 ms at a current value J at which the paper conveyance speed characteristic curve (starting characteristic of the paper conveyance motor 13) matches the starting characteristic of the ink ribbon motors M1 and M2.
(4) Subsequently, a current value at which the sheet conveyance speed characteristic curve (starting characteristic of the sheet conveying motor 13) and the starting characteristics of the ink ribbon motors M1 and M2 coincide with each other is obtained by a method similar to the above method. The operation of driving the ink ribbon motors M1 and M2 is repeated.
The main control unit 21 determines the acceleration profiles of the ink ribbon motors M1 and M2 obtained in the above (1) to (4): accelerations of the ink ribbon motors M1 and M2 (paper transport acceleration or paper transport acceleration and ink from the current values). The accelerations or speeds of the ribbon motors M1 and M2: the relationship with the above current values) are obtained and stored in the control table 32 in the ROM 23.

  During printing, the main control unit 21 controls the motor drivers 27 and 28 by referring to the contents of the control table 32 according to the paper conveyance acceleration, thereby controlling the speeds of the ink ribbon motors M1 and M2 according to the paper conveyance acceleration. And the ink ribbon motors M1 and M2 are driven at the same speed as that of the paper transport motor 13.

  Further, the main control unit 21 inputs a value to be arbitrarily added or subtracted to each value of the control table 32 according to the type of the ink ribbon 10 to be used, from either the operation unit 24 or the external I / F unit 25. As a result, the input value is added to or subtracted from the value in the control table 32. Further, the control table 32 is provided with a plurality of control tables corresponding to the type of the ink ribbon 10, and the main control unit 21 determines the type of the ink ribbon 10 to be used from either the operation unit 24 or the external I / F unit 25. Accordingly, when a selection signal for selecting a control table corresponding to the type of the ink ribbon 10 to be used is input from among the plurality of control tables, the control table corresponding to the type of the ink ribbon 10 is selected based on the selection signal. The selected control table is used as described above.

  According to the above embodiment, the ink ribbon motors M1 and M2 and the paper transport motor 13 are provided, and the drive of the ink ribbon motors M1 and M2 is started before the drive of the paper transport motor 13 is started. The ink ribbon can be fed following the paper without delaying the paper conveyance at the start of printing at the conveyance speed, and an appropriate tension can be generated on the ink ribbon. Smudge), ink ribbon wrinkles, and ink ribbon breakage can be suppressed.

  Further, according to the above embodiment, when accelerating the paper conveyance speed after the start of driving of the ink ribbon motors M1 and M2, the speed of the ink ribbon motors M1 and M2 is controlled following the paper conveyance acceleration. Regardless of the type, the ink ribbon can be transported at the same speed as the paper without sending the ink ribbon late to the paper or sending the ink ribbon earlier than the paper. Therefore, the ink ribbon does not sag or excessive tension is applied, and it is possible to suppress the occurrence of ink stains (smudge), ink ribbon wrinkles, and ink ribbon breakage.

  Moreover, according to the said embodiment, it has a function which adds or subtracts a fixed value with respect to a control table by the instruction | indication from the outside, and a some control table as a control table, and uses this some control table Since it has a function to select according to the ink ribbon, optimal control can be performed according to the ink ribbon to be used, and slack or excessive tension is applied to the ink ribbon regardless of the type of ink ribbon. This prevents ink smudges on the paper, ink ribbon wrinkles, ink ribbon rubbing traces from remaining on the paper, and ink ribbon breakage.

1 is a schematic view showing a thermal transfer printer according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating an electrical configuration of the printer. FIG. 6 is a characteristic diagram illustrating start characteristics of the ink ribbon motor and the paper transport motor when the ink ribbon motor starts to be driven earlier than the paper transport motor in the printer. FIG. 6 is a characteristic diagram illustrating an acceleration profile for each printing speed when the paper conveyance of the printer is started. FIG. 6 is a characteristic diagram showing a starting characteristic when a value of a current flowing through the ink ribbon motor is changed in a state where a constant load is applied to the ink ribbon motor in the printer in the actual machine state. FIG. 6 is a characteristic diagram in which an acceleration profile H at a paper conveyance speed of 8 ″ / s when the paper conveyance motor is driven simultaneously with the ink ribbon motor is superimposed on the ink ribbon motor start characteristic of FIG. 5 in the printer. FIG. 6 is a characteristic diagram showing the start characteristic of the paper transport motor and the start characteristic of the ink ribbon motor when the operation start time of the paper transport motor in the printer is delayed by 8 ms compared to the operation start time of the ink ribbon motor. FIG. 8 is a characteristic diagram showing a result recorded in FIG. 5 while shifting the time axis (the operation start time of the ink ribbon motors M1 and M2) in FIG. 7 in the printer. FIG. 2 is a block diagram illustrating an electrical configuration of the printer. 2 is a block diagram illustrating a configuration of a motor driver in the printer. FIG.

Explanation of symbols

r1, r2 Reel 10 Ink ribbon M1 Ink ribbon supply DC motor M2 Ink ribbon winding DC motor 21 Main control unit 24 Operation unit

Claims (6)

  In a thermal transfer printer that transports a sheet and prints on the sheet through an ink ribbon with an ink ribbon, the printer includes an ink ribbon motor for transporting the ink ribbon, and a stepping motor for transporting the sheet, A thermal transfer type printer having a control means for starting the driving of the ink ribbon motor at a predetermined time before starting the driving of the stepping motor at the start of printing.   2. The thermal transfer printer according to claim 1, wherein the control means controls the speed of the ink ribbon motor following the conveyance acceleration of the paper after the driving of the ink ribbon motor is started. .   3. The thermal transfer printer according to claim 2, further comprising a control table showing a relationship between a conveyance acceleration of the paper after the start of driving of the ink ribbon motor and a speed of the ink ribbon motor, and the control means conveys the paper. A thermal transfer type printer that controls the speed of the ink ribbon motor by referring to the control table according to the speed.   4. The thermal transfer printer according to claim 3, further comprising a function of adding or subtracting a predetermined value to the control table according to an instruction from the outside.   5. The thermal transfer printer according to claim 3, further comprising a plurality of control tables as the control table, and a function of selecting the plurality of control tables according to the ink ribbon to be used. Thermal transfer printer. A motor for a thermal transfer printer, comprising an ink ribbon motor for transporting an ink ribbon and a stepping motor for transporting the paper, and transporting the paper and printing on the paper with a print head via the ink ribbon In the control method, at the start of printing, the driving of the ink ribbon motor is started a predetermined time before the start of driving of the stepping motor.

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