JPS6027578A - Color thermal printer - Google Patents

Abstract

PURPOSE:To securely prevent positions of a printing paper and a printing film from being staggered at the time of reverse rotation, by intermediately providing a clutch means between a driving means for a platen and a driving system for a take-up side roll which consist of the same drive source. CONSTITUTION:When a pinion 4 is rotated in the direction for feeding the printing paper 4 forward by a motor, the platen 2 is driven through a belt 13, and simultaneously, rotation is transmitted from the pinion 14 through a gear 15, a pinion 16 and a gear 11 to a pulley 11, and a belt 8 is turned to rotate the roll 7 in the taking-up direction. Immediately before rotating the platen 2 reversely to feed the paper 4 backward in order to print in another color, an electric current is passed to a solenoid 26 to move a lever 24 upward in the direction of an arrow a3. By this, a lever 20 is lowered while being turned with a support shaft 19 as a center, whereby the gear 15 is separated from the pinion 14, and a clutch is disengaged. Simultaneously, a rubber roller 18 is lowered through a link 21 and is pressed against the gear 17, whereby a braking force is exerted on the pulley 11. Thereafter, the platen 2 is rotated reversely, and the roll 5 is also rotated reversely, thereby smoothly feeding the paper 4 backward.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a device that prints characters and the like based on input print information, and more particularly to a color thermal printer that prints print information in color using a thermal transfer method.

[Technology background]

2. Description of the Related Art In information processing devices, pixel-type (dot-type) printers, in which characters are formed by a collection of dots, have become popular in place of type-type printers for printing input information. Since the pixel type has a fast printing operation and can print by combining dots, it is possible to express freely and print arbitrary characters and patterns.

Depending on the form of energy used to print pixels, dot-type printers can be divided into mechanical (power) type represented by wire dot type printers, electric type represented by electrostatic printers, and electrophotographic type printers. Optical printers, thermal printers, and thermal printers such as thermal transfer printers are well known.

Further, thermal transfer printers can easily perform multicolor printing by using a color printing film in combination and melting and transferring the color ink on the color printing film to printing paper.

(Prior art and its problems) Figure 1 is a side view showing the outline of a color thermal printer. 1 is a thermal head 1, and a large number of heat generating resistors are arranged perpendicularly to the plane of the paper on the contact surface with the platen 2. is installed.To this thermal, between throat 1 and platen 2,
By passing the printing film 3 and the printing paper (printing medium) 4 overlappingly and selectively causing the heating resistor to generate heat,
The printing film 3 is selectively heated and the molten ink is transferred to the printing paper 4. Therefore, by selectively generating heat in the heating resistor while transporting the printing film 3 and the printing paper 4, characters, figures, etc. made up of aggregations of dots are continuously printed. 5 is a roll around which printing paper 4 is wound, 6 is a roll around which printing film 3 is wound, and 7 is a roll around which used printing film is wound, each of which is driven by a motor (not shown). That is, in synchronization with the rotation of the platen 2, the printing paper roll 5 and the printing film take-up roll 7 are rotated, and with the printing paper 4 and the printing film 3 stacked, the space between the platen 2 and the thermal head 1 is moved. Transport.

When performing color printing by thermal transfer, a color printing film 3 as shown in FIG. 2 is used. This color printing film 3 has a yellow ink surface 31, a blue ink surface 32,
Red ink surfaces 33 and the like are repeatedly arranged in a fixed order. When printing in color, first, with the yellow ink surface 31 overlapping the printing paper 4, while moving the color printing film 3 and the printing paper 4 at a constant speed in the direction of the arrow a1, the yellow color is printed based on the information to be printed. Then, the thermal head 1 prints yellow. Next time when printing blue,
The blue ink surface 32 is sent to the position of the thermal head 1, but before that, the printing paper 4 is returned to the original printing start position when yellow was printed, and the color printing film is placed on the paper surface on which yellow was printed. The printing paper 4 and the color printing film 3 are fed at a constant speed while the blue ink surfaces 32 of the paper are overlapped, and blue is printed based on the blue printing information. When printing the next red color, the printing paper 4 is returned to the light printing start position again, and the red ink surface 33
Information is printed in red, overlapping the

When performing color printing in this way, the motor rotates the platen 2 and the color printing film roll 7, transports the printing paper 4 and the color printing film 3 by a certain amount, prints a certain color, and then transfers the printing paper 4 and the color printing film 3 to the color printing film 3. is stopped, the platen 2 and the printing paper roll 5 are reversed, and the printing paper 4 is moved backward, and this operation is repeated.

By the way, when performing such an operation, the platen 2 and the one call 7 on the film taking side are generally driven by separate motors and controlled independently. In response, it has been proposed to reduce the number of motors used in order to eliminate the high cost of using multiple motors and controlling them separately. In addition, new problems arise, such as color printing film also retreating due to frictional force.

(Object of the Invention) The object of the present invention is to solve such problems in conventional color thermal printers, and to ensure that each part operates reliably in a printer in which the rotation of the platen and the transport of the color printing film are performed by the same drive source. The purpose is to make sure that it is carried out.

[Structure of the invention]

The technical means according to the present invention taken to achieve this objective is to overlap a color printing film for thermal transfer, in which ink surfaces of a plurality of colors are arranged in a fixed order, and a printing medium, and to connect a thermal head and a platen. In a color thermal printer, a color printing film is printed in a certain color by moving the printing medium forward, then the printing medium is moved back a predetermined amount, and the printing medium is overlapped with a different color ink surface and moved forward again to print in color. A braking means for stopping the rotation of the roll formed by winding or its drive system is provided, and a clutch means is interposed between the drive means of the platen and the drive system of the winding side roll, and the clutch means is A configuration is adopted in which means is provided for interlocking the above-mentioned braking means so that it operates when the valve is opened.

[Embodiments of the invention]

Next, examples will be used to explain how the color thermal printer according to the present invention is actually implemented. FIG. 3 is a side view showing an embodiment of a thermal printer according to the present invention. 7 is a film roll on the winding side, and an endless heald 8 is pressed against the outer periphery of the film roll 7. The belt 8 is wrapped around three pulleys 9.10.11. Boo 1J11 is a drive pulley, and as described later, it is connected to platen 2.
is connected to a drive motor. The pulley 10 is disposed on the opposite side of the roll 7 to the boot +79, and
Even if the outer diameter of the roll 7 changes, it is ensured that the belt 8 rests on the outer periphery of the roll 7. And on the outside of Heald 8,
The pinch roller 12 is pushed by a spring force. That is, as shown by the solid line, even if the outer diameter of the roll 7 is small, the pinch roller 12 moves in the direction of the arrow a2 to apply sufficient tension to the belt 8. As the outer diameter of the roll 7 increases as shown by the chain line, the pinch roller 12 is gradually pushed back in the direction opposite to the arrow a2.

In this way, since tension is constantly generated in the belt 8,
Even if the outer diameter of the roll 7 changes, the belt 8 is always in pressure contact with the outer periphery of the roll 7. Then, the pulley 11 is driven by a motor,
The frictional force between the belt 8 and the roll 7 generates rotational force on the roll 7. Since the heddle drive pulley I is driven by the same drive motor as the platen 2, the rotation speed of the belt 8 is equal to the rotation speed of the platen 2. Since the roll 7 is driven in pressure contact with the belt 8, the speed of the outer periphery of the roll 7 is always equal to the speed of the bell l-8.

Therefore, as shown by the solid line, when the outer diameter of the roll 7 is small, the number of rotations of the roll 7 is high, and as shown by the broken line, when the outer diameter of the roll 7 is large (as the number of rotations decreases, The rotational speed of the outer periphery of the printing film 3 is always constant.As a result, the transporting speed of the printing film 3 is always equal to the rotational speed of the platen 2 and is constant.

A driving motor (not shown) is connected to the pinion 14, which is connected to the platen 2 by a belt 13. A gear 15 meshes with the pinion 14, and a pinion 16 fixed to the gear 15 meshes with the gear I7. This gear 17 is fixed to the pulley 11.

Therefore, when the pinion 14 is rotated by the motor in the forward direction of the printing paper 4, the platen 2 is driven via the belt 13, and the pinion 14→gear 15−pinion 16→
The rotational force is transmitted in the order of gear 17 and pulley 11, and the rotation of pulley 11 rotates belt 8 as described above.
A rotational force is applied to the roll 7 in the winding direction. In this way, the printing paper 4 and the color printing film 3 advance by a predetermined amount, and then the printing paper 4 is retreated in order to print in a different color. In order to make this backward movement smooth, the gear 15 is removed from the pinion 14, and the braking rubber roller 18 is
presses the gear 17 and locks it. That is, a lever 20 is fixed to a shaft 19 on which the thermal head 1 is supported, and the gear 15 and pinion 16 are rotatably supported on this lever 20. Also, at the tip of this lever 20,
The support shaft of the rubber roller 18 is connected via the link 21 . The rubber roller 18 is attached to a lever 23 that rotates around a support shaft 22. One issue - Mulhead I
Similarly, a lever 24 supported by a support shaft 19 has a coil spring 2 for pressing the thermal head l against the platen 2.
5 is attached, and is also provided with a solenoid 26 for driving the lever 24 in the direction of arrow a3 against the coil spring 25.

Immediately before the platen 2 is reversed, the solenoid 26 is energized to raise the lever 24 in the direction of arrow a3. Then, the thermal head 1 rotates around the support shaft 19 and separates from the platen 2, and the lever 20 rotates and descends, causing the gear 15 to separate from the pinion 14 and disengage the clutch. At the same time, when the lever 2o is lowered, the rubber roller 18 is pulled down via the link 2I, and the support shaft 2
2 rotates downward and is pressed by gear 17.

Since the gear 15 comes off from the pinion 14 as described above, even if the motor rotates in reverse, the rotational force is not transmitted to the roll 7 on the winding side.Moreover, the rubber roller 18 is pressed against the gear 17, so that the rotational force is not transmitted to the roll 7 on the winding side. 17 and the boolean IJ11, the reversal of the roll 7 is reliably prevented. After preventing the roll 7 on the winding side from reversing in this way, the motor is reversed to reversely rotate the platen 2, and at the same time, the roll 5 of the printing paper is reversed to move only the printing paper 2 back by a predetermined amount, and the printing position is to cents. Also, the rubber roller 18
When the gear 17 is lowered, the gear 17 is pushed back slightly in its reverse direction. As a result, the color printing film 3 retreats slightly and the tension disappears, and the force pressing the printing paper 4 against the platen 2 is released, so that the printing paper 4 is smoothly retreated.

Note that if the printing paper 4 is to be retreated while the thermal head 1 is kept in pressure contact with the platen 2 side, the thermal head 1 should not be interlocked with the lever 20. Further, as long as braking is only applied directly or indirectly to the roll 7 on the winding side, means other than pressing the rubber roller 18 against the gear 17 can be used.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a braking means for stopping the rotation of the roll formed by winding the color printing film or its drive system, and the drive system of the platen drive means and the drive system of the winding side roll are connected to each other. A clutch means is interposed between the two. When the clutch means is disengaged and the printing paper is moved backward, the braking means is activated. Therefore, even though the same motor drives the platen and the take-up roll, it is possible to reliably prevent the take-up roll from reversing and prevent misalignment between the printing paper and the color printing film. , it becomes possible to improve printing quality.

[Brief explanation of drawings]

Figure 1 is a side view showing an overview of a color thermal printer.
FIG. 2 is a plan view of a color printing film, and FIG. 3 is a side view showing an embodiment of a color thermal printer according to the present invention. In the figure, 1 is a thermal head, 2 is a platen, 3 is a color printing film, 4 is a printing paper, 7 is a roll on the winding side of the color printing film, 8 is a belt, 14.16 is a binion, 15.17 is a gear , 18 is a rubber roller, 20
, 24 indicates a lever, and 26 indicates a solenoid. Patent applicant Fujitsu Ltd. agent Patent attorney Minoru Aoyagi

Claims (1)

[Claims] A color printing film for thermal transfer, in which ink surfaces of multiple colors are arranged in a certain order, is stacked on a printing medium, and color printing is performed while advancing between a thermal head and a platen, and then color printing is performed on the printing medium. only move back the specified amount,
In a color thermal printer that performs color printing by overlapping ink of a different color and moving it forward again, a braking means is provided to stop the rotation of the roll formed by winding the color printing film or its drive system, and the platen is A clutch means is interposed between the drive means of the roller and the drive system of the take-up roll, and means is provided for interlocking the brake means so that the brake means is operated when the clutch means is disengaged. color thermal printer.