JPH02120065A - Thermal transfer recording device - Google Patents

Abstract

PURPOSE:To prevent a skew from occurring in a recording medium and to achieve improvement of printing quality without generating color divergence by a method wherein pinching pressure of the recording medium on a side to which much of transfer ink of the recording medium is stuck is weakened. CONSTITUTION:A control part 40 reads numbers of counts of a left dot number counter 53 and a right dot number counter 54 via an I/O port 53, and drives a head pressing motor 19 in order to rotate a cam 18a by an angle based on a difference between both count numbers. When, for instance, the number of counts of a right half of paper 7 is large, frictional load of the right half of the paper 7 increases and the paper 7 has a fear of skewing right. Therefore, balance between left and right frictional loads to a thermal head 1 of the paper 7 is taken by intensifying left side pressing force of the paper 7, and the paper 7 is prevented from generating the skew. Divergence of the paper 7 when the paper 7 is back fed is prevented by preventing generation of the skew, and generation of color divergence in the case where printing on and after the second time is performed in a same area can be prevented to improve printing quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer recording device using a thermal head, and particularly to prevention of printing misalignment in a device that prints multiple times on the same area of a recording medium. It is.

[Conventional technology]

FIG. 2 is a perspective view showing the inside of a conventional thermal transfer color recording device, which employs a surface sequential method in which the ink ribbon surface is sequentially moved and a swing method in which the paper is moved in both forward and reverse directions.

In the figure, 1 is a thermal head in which a plurality of heating resistors are arranged in a line, and 2 is a platen facing the thermal head 1. Here, the thermal head 1 is fixed to a bracket 3, and the bracket 3 is supported by a support portion (not shown) so as to be rotatable about a fulcrum 3a.

A spring 4 is attached to the arm portion 3b of the bracket 3, and the arm portion 3b is pulled down to press the thermal head 1 against the platen 2. Further, a cam 5 is provided near the side of the lower portion 3C of the bracket 3 (the right side in the figure). When the rotational driving force of the motor 6 is transmitted to the cam 5 through the gears 6a and 5a, the cam 5 rotates and comes into contact with the side of the lower part 3c of the bracket 3. Then, the bracket 3 rotates about the fulcrum 3a in the direction of the arrow in the figure, thereby separating the thermal head 1 from the platen 2.

Further, 7 is a sheet of paper pulled out from a paper roll 7a, and 8 is an ink ribbon wound around a supply roll 8a and a take-up roll 8b. This ink ribbon 8 has the same width as the paper 7, and is provided with yellow, magenta, and cyan transfer inks in an area slightly larger than the recording range 9 of the paper 7, repeated in this order in the longitudinal direction of the ink ribbon 8. .

10 is a pressure roller that presses against the platen 2 and presses the paper 7; 11 is a ribbon sensor that detects a mark M indicating the position of the ink ribbon 8; and 12 is a ribbon feed motor that rotates the take-up roll 8b.

FIG. 3 is a block diagram showing the control system of the conventional example.

In the figure, 20 is a control section composed of ROM, RAM, timer, microprocessor, etc., and 21 is an interface line for inputting commands and print data from the outside. The control unit 20 also connects the control bus 24 and I1.
It is connected to the thermal head 1 via an 0 port 22, and to a motor driver 25 via a control bus 24 and an I10 port 23. The motor driver 25 drives the paper feed motor 26, ribbon feed motor 12, and head motor 6. Further, the control unit 20 connects the paper sensor 27 via the control bus 24 and the I10 port 23.
and the ribbon sensor 11.

FIG. 4 is a circuit diagram of the thermal head 1, and FIG. 5 is an operating waveform diagram of the thermal head 1.

Data to be printed is input to the I>ATA terminal of the shift register 30 in synchronization with a clock signal input to the CLOCK terminal. When you finish inputting one line of data,
A latch signal for transferring data from the shift register 30 to the latch circuit 31 is input to the LATCH terminal.

By transferring the data to the latch circuit 31, the shift register 30 becomes capable of inputting the next print data. The latch circuit 31 sends a signal based on the print data to the logic circuit 32, and the logic circuit 32 receives 5TBI~4 and the latch circuit 31.
The resistance element 33 (rt~rn
) to drive. Here, the signals 5TBI to 4 are signals for time-divisionally driving the heating element group into four groups, and each STB signal drives about 256 elements to reduce the power supply capacity.

Then, after moving the paper feed motor 26 and the ribbon feed motor 12 forward by one step (in the FP force direction F1 direction), the DATA terminal of the thermal head 1 is connected to the CLOCK terminal.
Transfer one line of data to the terminal, then transfer 5TB1 to 4
A signal with a constant pulse width is sequentially applied to energize the heating resistor element to print one line.

FIG. 6 is a flowchart showing the operation of the conventional example.

First, 851 (rsJ means step).

The same applies hereinafter), the control unit 20 receives print data for one screen. At this time, the thermal head 1 is in a down state separated from the platen 2.

In S52, the ribbon feed motor 12 is rotated,
The ribbon is moved until the ribbon sensor 11 detects the yellow mark. After this detection, the thermal head 1 is raised in 354 and pressed against the platen 2. In 6S55, printing for one line is performed, and n is set to n-1 in S56. n is 0 in S57
Repeat S55 and 356 until n becomes 0.
Proceed to step 358 and lower the thermal head 1.

Yellow printing is thus completed, and the paper is back-fed by n lines in step 359.

Next, magenta printing is performed in S60. In S60, operations similar to those in S52 to S358 described above are performed for magenta ink.

When magenta printing is completed, the paper 7 is back-fed by n lines again in S61.

Next, in step 862, cyan printing is performed. In S62, the above 5
The same operations as 452 to 358 are performed for cyan ink.

As described above, three colors are printed overlappingly in the same area 9 on the paper 7, and color image recording is completed, and the paper 7 is fed and ejected from the apparatus in S63.

[Problem to be solved by the invention]

However, in the above-mentioned conventional example, the frictional load applied to the paper 7 becomes different on the left and right sides of the paper 7 due to the balance between the left and right printing duties of the paper 7, and the traveling distances of the paper 7 on the left and right sides are not equal. Here, the printing duty is the ratio of the area to which ink is transferred to the area of the recording area of the paper 7.

That is, when the printing duty on the left half of the paper 7 is large, the frictional load applied to the left side of the paper 7 becomes large, so the traveling distance of the left side of the paper 7 decreases, and the paper 7 skews to the left. Further, when the printing duty on the right half of the paper 7 is large, the paper 7 skews to the right for the same reason. FIGS. 7(a) and 7(b) are explanatory views showing a state in which the paper 7 is skewed to the left and a state in which the paper 7 is skewed to the right.

Therefore, if the paper 7 is back-feeded after such a skew occurs due to the first printing, the paper 7
returns to the printing start position while being tilted diagonally, resulting in a problem of color misregistration and deterioration of print quality during the second printing.

Therefore, the present invention has been made to solve the problems of the prior art as described above, and its purpose is to:
It is an object of the present invention to provide a thermal transfer recording device capable of reducing paper misalignment and improving print quality.

[Means to solve the problem]

A thermal transfer recording device according to the present invention includes an ink ribbon provided with transfer ink and a plurality of heating elements arranged along the width direction of a recording medium, and the heat generated by the heating elements is used to transfer ink to the ink ribbon. a thermal head that transfers the ink ribbon onto a recording medium; a platen that is provided opposite to the thermal head and supports the ink ribbon and the recording medium; and a conveying means that conveys the recording medium in a length direction perpendicular to its width direction. recording, wherein the ink ribbon and the recording medium are stacked and sandwiched between the thermal head and the platen, and in this state, the transfer ink of the ink ribbon is transferred to the recording medium conveyed by the conveyance means. In a thermal transfer recording device that performs an operation on the same area of a recording medium multiple times, a pressure adjustment means that sets the pressure at which the recording medium is held between the thermal head and the platen to different values on both sides in the width direction of the recording medium. , a counting means for counting the number of drive signals applied to the thermal head for each of two predetermined regions of the plurality of heat generating elements; and a pinching means by the pressure adjusting means based on the counting result of the counting means. and a control means for controlling the application pressure.

[For production]

In the present invention, the counting means applies the drive signal of the thermal head to two predetermined regions of the plurality of heating elements, for example, each of the left half and right half of the plurality of heating elements divided into left and right halves. Count.

The pressure adjustment means sets the pressure at which the recording medium is held between the thermal head and the platen to different values on both sides in the width direction of the recording medium.

The control means controls the clamping pressure of the recording medium by the pressure adjustment means based on the counting result of the counting means.

The reason why the clamping pressure is controlled using the above configuration is that, for example, when a recording medium has a lot of transfer ink attached to the right half of the recording medium, the frictional load acting between the thermal head and the recording medium is on the right side. This causes the recording medium to skew to the right, so the clamping pressure on the left half of the recording medium is increased (or the clamping pressure on the left half is weakened) to balance the left and right frictional loads, thereby reducing the skew. This is a measure to prevent the occurrence.

By preventing the occurrence of skew in this way, it is possible to reduce paper misalignment, and almost no color misregistration occurs even if printing is performed multiple times on the same area of the recording medium.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIGS. 1(a) and 1(b) are a front view and a left side view schematically showing the internal structure of a thermal transfer recording apparatus according to the present invention. In this figure, the same components as in FIG. 2 are given the same reference numerals and will be explained.

That is, in FIG. 1, 1 is a thermal head in which a plurality of heating resistors are arranged in a line in the paper width direction, 2 is a platen that presses against the thermal head 1, and 3 is a thermal head that rotates around a fulcrum 3a. Bracket for supporting head 1, 4
is a spring attached to the arm portion 3b of the bracket 3; 5 is a cam provided near the lower part 3C of the bracket 3; 6 is a head motor that provides rotational driving force to the cam 5 via gears 6a and 5a. .

In the above configuration, when the cam 5 rotated by the head motor 6 comes into contact with the side of the lower part 3C of the bracket 3, the bracket 3 moves in the direction of the arrow in the figure ((b) in the figure) about the fulcrum 3a.
clockwise) to separate the thermal head 1 from the platen 2 and bring it down. Also, cam 5
When the bracket 3 separates from the lower part 3C of the bracket 3, the bracket 3
is rotated counterclockwise by a spring 4 to bring the thermal head 1 into contact with the platen 2 and bring it into the up position.

Further, 7 is paper (recording medium), and 8 is an ink ribbon. The ink ribbon 8 has the same width as the paper 7, and is provided with yellow, magenta, and cyan transfer inks in areas slightly larger than the recording range of the paper 7, which are repeated in the longitudinal direction of the ink ribbon 8.

Note that 10 and 13 are pressure rollers that press against the platen 2 and press the paper 7, and 14 and 15 are guide rollers that guide the ink ribbon 8.

Furthermore, in this embodiment, in addition to the above-described configuration, the pressing force (the clamping pressure of the paper 7) with which the thermal head 1 is pressed against the platen 2 is applied to both sides of the paper 7 in the width direction (see FIG.
In a), a pressure adjusting means is provided which has a function to vary the pressure on both the left and right sides (I!!I).

This pressure adjustment means includes a left spring 16a and a right spring 16b that press the thermal head 1 against the platen 2.
A buck member 17a and a buck member 17b that are rotatably provided around a rotating shaft 17c and support the ends of the left spring 16a and the right spring 16b, and a left cam that comes into contact with these buck members 17a and 17b. 18a and a right cam 18b.

Here, the left cam 18a is an eccentric cam whose rotating shaft 19c is not at the center, as shown in FIG.

Therefore, the rotational driving force of the head pressing motor 19 is transferred to the gear 19.
a and the gear 19b, both the left cam 18a and the right cam 18b rotate, but the right cam 18
b is cylindrical, so the position of the bar member 17b does not change and the pressing force on the right side of the thermal head 1 does not change.On the other hand, the left cam 18a is an eccentric cam, so when it is rotated, the bar member 17a It rotates around the shaft 17c to change the pressing force on the left side of the thermal head 1.

FIG. 8 is a block diagram showing the control system of this embodiment. In the figure, reference numeral 40 is a control unit composed of a ROM, RAM, timer, microprocessor, etc., and reference numeral 41 is an interface line for inputting commands and print data from the outside. The control unit 40 also connects a control bus 44 and I10.
It is connected to the thermal head 1 via a boat 42 and to a motor driver 45 via a control bus 44 and an I10 boat 43. The motor driver 45 drives a paper feed motor 46 , a ribbon feed motor 47 , a head motor 6 , and a head press motor 19 . Further, the control unit 40 is connected to a paper sensor 48 and a ribbon sensor 49 via a control bus 44 and an I10 boat 43.

Further, 50 is a counter for the left and right portion connected to the clock signal line via the I10 board 42, 51 and 52 are AND circuits, and 53 is the left half of the left half of the heating resistor of the thermal head 1 divided into two regions. A left dot counter 52 counts the number of printed dots, and a right dot counter 52 counts the number of printed dots on the right half.

Here, the counter 50 is calculated by the AND circuit 51.
A clock signal is input to one of 52. Specifically, for example, if one line has 1024 dots, 1 to 5
The clock signal up to 12 dots is input to the AND circuit 49, and the left dot number counter 53 selects I10 baud 1 to 42.
The number NLEFT of data signals input to the thermal head 1 via the NLEFT is counted. Further, a clock signal of 513 to 1024 dots is input to the AND circuit 52, and the right dot number counter 54 counts the number of data signals NRIGold input to the thermal head 1 via the I10 port 42.

Further, the control section 40 reads the counts of the left dot number counter 53 and the right dot number counter 54 via the I10 boat 55, and in order to rotate the cam 18a by an angle based on the difference N5OB between the two counts, the head pressing motor 19 is operated.
drive.

FIG. 9 is a diagram showing how the length 1 of the springs i6a and 16b changes depending on the rotation angle of the head pressing motor 19, and FIG. This is a correction table showing the correspondence between the difference in counts N SOB stored in the ROM, the rotational position of the head pressing motor 19, and the pressing force of the thermal head 1.

The rotational position corresponding to the count difference N5UB is called from this correction table, and the head pressing motor 19 is driven to change the pressing force against the platen 2 on the left side of the thermal head 1.

The reason why the control is performed as described above is that, for example, when the count number NRIGHT on the right half of the paper 7 is large, the frictional load on the right half of the paper 7 becomes large and there is a risk that the paper 7 will skew to the right. This is to balance the left and right frictional loads of the paper 7 on the thermal head 1 by increasing the pressing force on the left side, thereby preventing the paper 7 from skewing.

By preventing the occurrence of skew, it is possible to prevent the paper 7 from shifting when back-feeding the paper 7, prevent color misalignment when printing in the same area for the second time onwards, and improve print quality. be able to.

FIG. 11 is a flowchart showing the operation of this embodiment. The operation of this embodiment will be briefly and concretely explained based on this figure, FIG. 1, and FIGS. 8 to 10.

First, in the yellow printing operation, the control unit 40 connects the interface line 41 from an external device (not shown) at Sl.
The print data is received via the receiving buffer RAM, and the print data for one screen is stored in the reception buffer RAM. At this time, the thermal head 1 is in a down state separated from the platen 2.

The ribbon feed motor 47 is rotationally driven in S2, and when the ribbon sensor 49 detects a yellow mark in S3, the process advances to S4 and the ribbon feed motor 47 is stopped. At this point, the position of the ink ribbon 8 becomes the yellow printing start position.

In S5, the left count number N LE FT and NRIG old in the work area of the control unit 40 are set to 0. In S6, the left dot number counter 53 and right dot number counter 54 are reset. In S7, the head motor 6 is rotated to raise the thermal head 1 and press it against the platen 2.

In S8, the counter 50 is initialized for the left and right swing, and S8
At step 9, data for one line is transferred to the thermal head 1, and printing for one line is performed at SIO.

In Sll, the contents of the left dot number counter 53 are set to I10.
It is read through the counter 55 and added to NLFFT, and S
At step 12, the contents of the right dot number counter 54 are read via the I10 counter 55 and added to NRIGIIT.

Next, at 313, the difference between printed dots N5UB = N
LEFT-N RIGIIT is calculated, and in step 314, one of the correction values Ao to A7 corresponding to N SOB is called from the correction table of FIG. In S15, the head pressing motor 19 is driven to adjust the pressing force of the thermal head 1 to the value F in the correction table. Adjust to ~F7. At 816, the paper feed motor 46 and the ribbon feed motor 47 are rotated by one line to move the paper 7. In S17, 1 is subtracted from n, which is the total number of print lines in the print area.

In 318, it is determined whether n is 0 or not, and steps S8 to 317 are repeated until n becomes 0.

Then, when n=o, yellow printing is finished and S
At step 19, the thermal head 1 is lowered.

At 320, the paper is back-fed by n lines,
Move on to magenta printing operation. In S21, which generally shows magenta printing operations, operations similar to those from Sl to 519 are performed for magenta ink.

Thereafter, at 822, the paper is back-fed by n lines and a cyan printing operation is started. At 323, which generally shows the cyan printing operation, the same operations as from Sl to 319 are performed for cyan ink.

At this point, a color image is recorded in the recording area 9 of the paper 7 using three colors of ink: yellow, magenta, and cyan. In S24, the paper is fed and printing ends.

In the actual glaze example above, a case has been described in which the pressing force of the thermal head 1 is changed to change the clamping pressure of the paper 7 between the platen 2 and the thermal head 1, but the present invention is not limited to this. , the thermal head 1 may be fixed and the platen 2 may be pressed against the thermal head 1.

Further, in the above embodiment, the case where the pressing force was changed on the left side of the thermal head 1 was explained.
It is not limited to this, but the right ll71t of the thermal head 1
Alternatively, a configuration may be adopted in which the pressing force is varied on both sides.

Further, in the above embodiment, a combination of a spring and a cam was used as a device for changing the pressing force of the thermal head 1, but the device is not limited to this, and other elastic bodies or other aluminum can be used in combination. Other configurations may also be adopted.

Furthermore, in the above embodiment, in order to know the printing duty, the heating element of the thermal head 1 is divided into two areas, left and right, and all drive signals of each area are counted. It is also possible to count the drive signals for a short range representing the two left and right regions without counting the drive signals.

〔Effect of the invention〕

As explained above, according to the present invention, by relatively weakening the pinching pressure of the recording medium on the side of the recording medium to which a large amount of transfer ink is attached, the frictional load caused by the thermal head and the platen on the recording medium is reduced. It is possible to balance the left and right sides, thereby preventing skew from occurring in the recording medium. Therefore, when performing the next printing by backfeeding the recording medium, color misregistration does not occur, and printing quality can be improved.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a front view and a left side view showing the internal structure of an embodiment of a thermal transfer recording device according to the present invention, and FIG. 2 is a perspective view showing the inside of a conventional thermal transfer recording device. , Fig. 3 is a block diagram of the conventional device, Fig. 4 is a circuit diagram of the thermal head, Fig. 5 is an operation waveform diagram of the thermal head, Fig. 6 is a flowchart showing the operation of the conventional device, and Fig. 7 ( a) and (b) are explanatory diagrams for explaining the problems of the conventional device, Fig. 8 is a block diagram of this embodiment, and Fig. 9 shows the relationship between the rotation angle of the head pressing motor and the length of the spring. FIG. 10 is a diagram showing the correction table of the control section, and FIG. 11 is a flowchart showing the operation of this embodiment. 1...-thermal head, 2...platen, 7...
・Paper (recording medium), 8... Ink ribbon, 16a・
...Left spring, 16b...Right spring, 17a
, 17b - bar member, 18a... left cam, 18b... right cam, 19
...Head pressing motor, 40...Control unit (control means), 46...Paper feed motor (transport means), 50...
・The left and right distribution is a counter, 53...Left dot number counter, 54...Right dot number counter.

Claims (1)

[Scope of Claims] An ink ribbon provided with transfer ink and a plurality of heating elements arranged along the width direction of a recording medium, the transfer ink of the ink ribbon being recorded by the heat generated by the heating elements. A thermal head that transfers images onto a medium; a platen that is provided opposite to the thermal head and supports the ink ribbon and the recording medium; and a conveyance means that conveys the recording medium in a length direction perpendicular to its width direction. The ink ribbon and the recording medium are overlapped and sandwiched between the thermal head and the platen, and in this state, a recording operation is performed in which the transfer ink of the ink ribbon is transferred to the recording medium conveyed by the conveyance means. , in a thermal transfer recording device that performs printing on the same area of a recording medium multiple times, pressure adjusting means for adjusting the pressure at which the recording medium is held between the thermal head and the platen to different values on both sides in the width direction of the recording medium; a counting means for counting the number of drive signals applied to the thermal head for each of two predetermined regions of the plurality of heating elements; and a pinching pressure by the pressure regulating means based on the counting result of the counting means. 1. A thermal transfer recording device comprising a control means for controlling.