JPS62282947A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To always obtain high printing quality, by allowing a transfer speed to correspond to energizing force by providing an energizing means capable of setting two or more kinds of energizing forces for pressing a printing head to a platen and a transfer means capable of changing over the relative transfer speed of the printing head and paper. CONSTITUTION:A reflection type sensor 110 detects smoothness and CPU controlling a printer collectively rotates a motor 106 on the basis of the detection result to move a spring support member 104 and sets the pressing force of a thermal head 101 to a platen roller 107. Therefore, the pressing force can be set corresponding to the smoothness of printing paper obtained by the reflection type sensor 110. Corresponding to said smoothness, a motor 108 is controlled at the speed corresponding to pressing force by a motor control means and the printing paper is printed at a printing speed optimum to the printing paper. Therefore, a high speed property, a high printing grade imparting property and a noise suppressing property are provided and printing can also be applied to low smoothness paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer printer, and more particularly to a thermal transfer printer capable of printing on low-smooth plain paper.

[Prior Art] In recent years, with the spread of thermal printers, various demands have been placed on thermal printers, especially thermal transfer printers. One of them is high speed, and the other is high print quality.

Conventionally, there are almost no thermal transfer printers that have both of these two characteristics.

Some conventional thermal printers change the pressing force of a thermal head against thermal paper in order to change the color density. It is disclosed in Utility Model Application Publication No. 58-29438.

Fig. 6 is a schematic diagram of a conventional embodiment, and is shown in U.S. Pat.
This is a thermal printer disclosed in No. 38, and will be briefly described below.

1 is a thermal head in which a heating element is arranged; 2 is a motor that serves as a driving source for transporting the thermal head; 3 is a platen;
5 is a belt that transmits the driving force of the motor to the thermal head, and 6 is a guide shaft of the thermal head, which also has the role of transmitting the pressing force to the platen. 4 is a plunger for switching the pressing force. Two types of pressing forces are obtained by turning the plunger 4 on and off.

In this conventional example, the purpose is to change the print density! : Since it was possible to produce two colors, it was impossible to apply it to a thermal transfer printer.

[Problems to be Solved by the Invention] It is known that print density can be changed by changing the pressing force of the thermal head in thermal transfer printers as well. However, in thermal transfer printers, simply increasing the pressing force can cause trailing phenomenon due to dot filling and stains due to heat accumulation in the thermal head, deteriorating print quality. Ta.

In addition, although printing on plain paper has become a market demand in recent years, it is completely impossible to print on low-smooth paper such as bond paper, which is widely used in offices in the United States. There were many printers.

Furthermore, the conventional switching device has a plunger, which is a source of loud noise, which is a factor that detracts from the most important characteristic of thermal printers, which is quietness.

The purpose of the present invention is to eliminate such drawbacks of the prior art,
It is an object of the present invention to provide a thermal transfer printer that has high speed, high print quality, and quietness, and is capable of printing even on low-smooth paper.

[Means for Solving the Problem] The thermal transfer printer according to the present invention includes a biasing unit that can set two or more types of biasing force for pressing the print head against the opposing platen, and a biasing unit that can set the relative transfer speed of the print head and paper. The present invention is characterized in that it has a switchable transfer means, and the transfer speed set by the transfer means is made to correspond to the urging force set by the urging means.

Furthermore, by adding applied energy control means for controlling the applied energy to the printing elements on the print head, it is possible to apply applied energy to the printing elements that is optimal for the relative transport speed between the thermal head and the printing paper. It is also characterized by

[Function] In the present invention, when the thermal transfer printer selects a high print quality mode using a control code, a manual switch, or even a printing paper smoothness measuring device, the thermal transfer printer selects the high print quality mode by a command from a central control device such as a CPU. , high print quality is achieved by increasing the biasing force of the print head and reducing the relative speed of the print head with the paper. At this time, when the paper is of low smoothness, the energy applied to the print head can be increased to further improve the print quality. Furthermore, when the high-speed printing mode is selected, the biasing force of the print head is reduced, and the relative transport speed between the print head and the printing paper is also increased, making high-speed printing possible.

[Embodiment] An embodiment of the present invention will be described in detail using a thermal transfer printer having a thermal head as a print head and a heat generating element as a print element.

FIG. 1 is a schematic diagram of a thermal head support portion of an embodiment of a thermal transfer printer according to the present invention.

FIG. 1(a) is a plan view, and FIG. 1(b) is a sectional view taken along the line. 8 is a round platen, 9 is a heat dissipation plate of the thermal head 10, 11 is a support frame, 12 is a biasing force transmission lever rotatably mounted on a shaft 13, 20
21 is a worm gear attached to the motor shaft, 22 is in contact with the worm gear, and arrows G and H
Head-up lever installed so that it can reciprocate in the direction, 23
is a gear that is meshed with the worm gear 21 and rotates around the shaft 24, and transmits the power for winding up the ribbon cassette 4o during printing. The head-up lever 22 is engaged with a notch 14 installed in the biasing force transmission lever, and as the shaft of the motor 20 rotates in the direction F, the head-up lever moves in the direction of arrow H to release the head from the pressed state. When the shaft of the motor 20 is released and the shaft of the motor 20 rotates in the E direction, the head up lever 22 moves in the direction of the arrow G and becomes free within the notch 14.

30 is a switching lever for switching between two types of biasing force, and is movable back and forth in the direction of arrow B.
．． It is installed so as to be rotatable in the L direction using 34 as a fulcrum. A coil spring 31, which is a type of elastic member, is engaged with the switching lever 30 and biased in the direction of the arrow. This biasing force is transmitted to the biasing force transmission lever by the pin 32 and the notch 15 set up on the switching lever. The cutout 15 has at least two recesses 16,17, making it possible to stabilize the pin 32 in position.

When the switching lever 30 is moved in the direction of arrow B and the pin 32 is engaged with the recess 17, the lever ratio between the force point of the coil spring 31 and the shaft 13 serving as a fulcrum increases, and the thermal head 10 is pressed against the platen from the back side. Pressure force (arrow ■
) increases.

When printing is completed, the motor 20 rotates in the F direction, and the head up lever 22 moves in the arrow H direction to release the biasing force of the coil spring 31. At this time, a force is applied in the direction of arrow J by the compression coil spring 41, and the thermal head 1
0 is away from the platen. The elastic member 31, the switching lever 30, and the urging force transmission lever 12 constitute the urging means as main components.

FIG. 2 is an overall view of a mechanical section of an embodiment of a thermal transfer printer according to the present invention, and the same parts as in FIG. 1 are designated by the same numbers and their explanation will be omitted.

50 is a frame of the thermal transfer printer, 60 is a step motor which is part of the transfer means for transferring the thermal head 10 in the platen axis direction and serves as a driving source, 62 is a belt that transmits the driving force to the support section, and 63 is a bell I. 62 and a wheel train engaged with the step motor 60, 51 a left side frame erected on the frame 50, 52 a right side frame, and 53 a guide shaft for guiding the support portion 61, respectively.

In the thermal transfer printer, when a high print quality mode that requires a large urging force is selected, the step motor 60 pushes the thermal head support 61 against the left side frame 51 prior to printing, and the switching lever 30 is moved in the direction of the arrow. The printer is moved in direction B to start a predetermined printing operation. On the other hand, in a high-speed printing mode that requires a small urging force, the switching lever 30 is moved in the direction of arrow C by pressing against the right side frame 52. Step motor 6o for thermal head transfer
The left side frame 51, the right side frame 52, and the switching lever 30 constitute a switching means for switching the biasing force. Naturally, the switching lever 30 is operated so as not to come into contact with the side frame during a predetermined printing operation.

By increasing the number of recesses in the notch 15 installed in the urging force transmission lever, it is possible to create many types of pressure contact forces of the head. In addition, in this embodiment, the coil spring 3
Although the explanation was given by changing the force point in step 1, the same effect can be obtained by moving the fulcrum and changing the lever ratio.

FIG. 3 is a schematic diagram showing the configuration of a thermal transfer printer according to the present invention. Components that are the same as those in FIGS. 1 and 2 are designated by the same numerals, and explanations thereof will be omitted.

Reference numeral 100 indicates a mechanical section of the thermal transfer printer, 10a indicates a heat generating element disposed on the thermal head, and 60a indicates a coil of the step motor 60.

Reference numeral 70 denotes applied energy control means for determining the applied energy to the heating element 10a, and the description and configuration of each element will be described below.

For example, the applied energy control means can set two or more types of energy to be applied to the heat generating element by switching the energization time to the heat generating element.

71 is a capacitor that is charged via resistor 73 (or] Landistav 6), resistor 74, and polyurethane 75.
Zero or more components discharged by the transistor 72 constitute a charging/discharging circuit section.

Resistors 77, 78, 79. The thermistor 80 constitutes a reference voltage section.

Reference numeral 81 is a voltage comparison circuit, which is turned on and off depending on the charge level of the capacitor 71, and the reference voltage section is as follows.
Since the thermistor 80 detects the ambient temperature or the temperature of the thermal head, the optimum stamping channel for the thermal head is always determined.

The operation of this applied energy control means is as follows.

The CPU 90, which controls the thermal transfer printer, controls the transistors in synchronization with the printing timing!・Riga human power Tg is output. Transistor 72 momentarily discharges capacitor 71 and then turns off. Then resistor 73.
Charging of the capacitor 71 via 74 and the like is started.

The time required for the charge level of the capacitor 71 to reach the potential at eight points in the reference voltage section is outputted from the voltage comparison circuit 81 as a pulse width TW. The transistor 76 is a switch that changes the output pulse width TW, and when it is on, the pulse width TW is short, and when it is off, it is long. The volume 75 is a density adjustment volume installed to manually vary the density from outside the thermal transfer printer.

The output of the applied energy control means 70 is transmitted to the head driver 8.
The signal is transmitted to the transistor 82 which turns on and off the power supply terminal 83a of No. 3. The head driver 83 becomes operable for the pulse width TW, and appropriate applied energy is applied to the heat generating element 1.
Added to 0a.

64 is a motor driver, 65 is a voltage control transistor that varies the voltage applied to the drive coil 60a, 66 is a resistor, and 67 is a speed control circuit, which includes the motor 60, motor driver 64, voltage control transistor 65, and speed control circuit. 67 constitutes a transport means as a main component.

68 is a print mode changeover switch for selecting high-speed printing mode and high print quality mode; 69 is a power input terminal; 8
4 is a print mode output terminal.

(Operation of the embodiment) When the high-speed printing mode is selected by the switch 68,
The CPU 90 outputs a low level to the print mode output terminal 84. The transistor 76 in the applied energy control means 70 is turned on, and the output pulse width of the voltage comparison circuit 81 is
Short pulse width can be output. In addition, the voltage control I/range star 5 is also turned on, and the motor 60 is driven at high voltage.
High-speed printing is possible.

When the print data is input to the CPU 90, the CPU 90 operates the motor 60 in order to reduce the urging force of the aforementioned urging means. Thereafter, the printing operation is performed while the motor 60 is operated at high speed by the transfer means.

Conversely, when the low speed high print quality mode is selected by the switch 68, the print mode output terminal 84 is output from the CPU 90.
A high level is output to. Applied energy control means 7
When the value is 0, a long pulse width can be output, and the motor 60 can operate at low speed.

Generally, in a step motor, the voltage applied to the drive coil 60a is reduced in order to suppress temperature rise during low speed rotation.

When the print data is input to the CPU 90, the CPU 90 switches the aforementioned biasing means to increase the biasing force. Thereafter, a printing operation is performed while rotating the motor 60 at a low speed.

Speed control port! 867 is for switching the drive frequency of the step motor in response to a command from the CPU 90.
A method of changing the frequency by software means within the PU 90 may also be used.

FIGS. 4(a) and 4(b) are schematic diagrams showing another embodiment of a thermal transfer printer according to the present invention. FIG. 4(a) is a schematic diagram of the mechanism section.

Reference numeral 101 denotes a line-type thermal head with heating elements arranged in the direction of the printed digits, and 102 is a head support member that also serves as a heat sink, and is rotatable about a fulcrum 102a. 103 is a coil spring that provides an urging force to press the thermal head 101 against the platen 107; 104 is a spring support member; 105
106 is a gear that engages with the spring support member 104, and 106 is a gear 1.
05 shows a pressing force setting motor that rotates.

The platen 107 is rotatably installed by a motor 108. The motor 108 is a source for transporting the printing paper 111 to the thermal head 101, and generally a step motor is used as in a serial printer.

109 is an ink ribbon, and 110 is a reflective sensor that is a type of measuring means for measuring the smoothness of the printing surface of the printing paper 111.

FIG. 4(b) shows a circuit diagram of the reflective sensor 110 which is a measuring means, in which 121 is a light emitting part and 122 is a light receiving part. 120 is an A/D converter that converts the output voltage of the light receiving section from analog to digital.

The output of the reflective sensor is, when the printing paper is smooth,
The output voltage is high; conversely, when the smoothness is poor, such as with pound paper, the output voltage is low.

(Operation) The reflective sensor 11'0 detects the smoothness, and based on this, the CPU, which generally controls the printer, rotates the motor 106 in the direction of arrow U or arrow V.

This allows the spring support member to reciprocate in the directions of arrows N and M.

When the smoothness is low, the spring support member is moved in the direction of arrow N, and the pressing force of the thermal head 101 is increased;
When the smoothness is high, the spring support member is moved in the direction of arrow M.

When printing starts, the platen roller 107 of the thermal head 101 is activated based on information from the reflective sensor 110.
A pressing force is set, and in accordance with this, the motor 108 is controlled by a motor control means (not shown) at a speed corresponding to the pressing force, and printing is performed on the printing paper at an optimal printing speed.

The pressing force can be set according to the smoothness of the printing paper obtained by the above-mentioned reflective sensor 110. That is, depending on the rotation angle of the pressing force setting motor 106,
This is because the strokes of the spring support member 104 and the head support member 102 can be varied steplessly, and an arbitrary pressing force can be obtained.

Further, the urging means of this embodiment can also be used as a release means for releasing the pressing force of the thermal head. When the pressing force setting motor 106 is rotated in the direction of arrow U, the spring support member 104 moves in the direction of arrow M.

When this moving distance exceeds a predetermined value, the thermal head 10
1 is separated from the platen 107. This allows the ink ribbon 109 and printing paper 111 to be set.

[Effects of the Invention] According to the present invention, it is possible to always obtain high print quality regardless of the smoothness of the surface of the printing paper.

This is because, for low-smooth paper, reducing the relative speed of the thermal head and increasing the pressing force on the printing paper improves the ink penetration into the printing paper. Furthermore, by increasing the pressing force and increasing the energy applied to the thermal head using the applied energy control means, the permeability into the paper is further increased, and it is possible to improve the permeability of the paper, such as bond paper used in offices in the United States. It also becomes possible to print on low smooth paper.

FIG. 5 is a graph showing the relationship between the drive torque of the step motor used as the drive source of the transfer means of the present invention and the perpendicular frequency (PPS). In general, a step motor has a larger driving torque at point P, where the rotational frequency is low, than at point Q, where the rotational frequency is high.In other words, in the thermal transfer printer according to the present invention, in the high-speed printing mode, the pressing force of the thermal head is reduced. Therefore, it has the advantage of being able to use a motor that is smaller and consumes less power than conventional motors.

As described above, the present invention has been described using, as an example, a thermal head equipped with a heat generating element, but it can also be applied to an energizing type thermal transfer printer that has an electrode as a printing element and generates heat by a resistive layer coated on a thermal transfer ribbon. has a similar effect.

Moreover, printing is a concept that includes all printing such as characters, symbols, and figures.

1 is a schematic illustration of an example thermal head support.

8...Platen 10...Thermal head 31...Elastic member FIG. 2 is an overall view of the mechanism of an embodiment of the thermal transfer printer according to the present invention.

40 . . . Ribbon cassette 60 . . . Step motor of transfer means FIG. 3 is a schematic diagram showing the structure of a thermal transfer printer according to the present invention.

70...Applied energy control means Fig. 4(a) (
b) is a schematic diagram showing another embodiment of a thermal transfer printer according to the invention;

FIG. 5 shows the characteristics of a step motor used as a drive source for the transfer means.

FIG. 6 is a schematic diagram of a conventional embodiment.

that's all Ward (Q) Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) A printing head in which a printing element is arranged, a platen arranged opposite to the printing head, an urging means whose basic components are an elastic member that presses the printing head against the platen, and a biasing means for pressing the printing head against the printing paper. In a thermal transfer printer, the urging means is capable of setting two or more types of urging force for pressing the print head, and a transfer means for moving the print head relative to the printing paper. the urging force; and the transfer means capable of setting two or more types of transfer speed;
A thermal transfer printer characterized in that the transfer speed corresponds to the above-mentioned transfer speed. (2) an applied energy control means for determining the applied energy to the printing element disposed on the print head; the applied energy control means is capable of setting at least two or more types of applied energy; and the transfer speed 2. The thermal transfer printer according to claim 1, wherein the energy applied to the printing element of the print head is determined in accordance with the biasing force. (3) The thermal transfer printer according to claim 2, wherein the applied energy control means is capable of setting two or more types of energization time to the printing element.