JPH08187924A - Thermal transfer printer - Google Patents

Abstract

PURPOSE: To well perform the recording on recording paper by preventing an ink ribbon from slackening when a thermal head and a platen roller are brought to a pressure contact state or separated. CONSTITUTION: When a thermal head, an ink ribbon and recording paper are brought into contact with a platen roller under pressure or the thermal head is separated from the platen roller, a motor 8 is rotated counterclockwise only for a definite time. Whereupon, a worm gear 10 and bevel gears 11, 13 are rotated counterclockwise in a drawing and an arm 12 is revolved in the direction shown by an arrow E and the bevel gear 13 is meshed with a bevel gear 20. Therefore, the rotation of the motor 8 is transmitted to a supply shaft 21 through a worm 9, the worm gear 10 and the bevel gears 11, 13, 20 and a supply roll is rotated in the direction shown by an arrow C and, therefore, the ink ribbon is taken up by the supply roll to be tensioned between the supply roll and a take-up roll in the contact state with the thermal head or to be housed in an ink cartridge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer which heats ink on an ink ribbon with a thermal head and transfers it onto recording paper.

[0002]

2. Description of the Related Art With the widespread use of personal computers in recent years, there is an increasing need for printers that output characters, symbols, graphics, etc. on a monitor screen. Among them, a thermal transfer printer that heats the ink of an ink ribbon with a thermal head to transfer it to a recording sheet has been attracting attention because of its low noise during operation and its advantage in downsizing of the printer.

A conventional thermal transfer printer will be described below.

2 and 3 show the basic structure and operation of a conventional thermal transfer printer. Reference numeral 1 denotes a supply roll 2 and a take-up roll 3 which are rotatably mounted, and the supply roll 2 and the take-up roll. The ink cartridge 1 has an ink ribbon 4 mounted between the ink cartridge 3 and the ink ribbon 3, and the ink cartridge 1 can be freely attached to and detached from an ink ribbon conveying means (not shown). 5
Is a thermal head that heats the ink of the ink ribbon 4 and transfers it to the recording paper 6. The thermal head 5 has a recording position (see FIG. 2) where the ink ribbon 4 and the recording paper 6 are pressed against the platen roller 7. It moves between a standby position (see FIG. 3) separated from the platen roller 7.

In the conventional thermal transfer printer configured as described above, the recording paper 6 is the thermal head 5 and the platen roller 7.
2 from the right direction (direction of arrow A) in FIG. 2 to the predetermined position, the thermal head 5 moves to the recording position, and the thermal head 5, the ink ribbon 4 and the recording paper 6 move to the platen roller 7. Crimp on. When the heating elements (not shown) of the thermal head 5 generate heat according to the image signals, the ink of the ink ribbon 4 is transferred to the recording paper 6, and an image of characters, symbols, figures, etc. is formed on the recording paper 6. . During this time, the used ink ribbon 4 is sequentially wound by the winding roll 3 which rotates in the counterclockwise direction (arrow B direction) in FIG. When the recording is completed, the thermal head 5 returns to the standby position and is separated from the platen roller 7, and the recording paper 6 is ejected from the platen roller 7.

By the way, as shown in FIG. 3, the ink ribbon 4 mounted between the supply roll 2 and the take-up roll 3 is wound or wound even if the thermal head 5 returns to the standby position. It is in a state of being pulled out from the ink cartridge 1 without being rewound on the take-up roll 3.

Therefore, when the ink cartridge 1 is detached from the ink ribbon transporting means during standby, the ink ribbon 4 is caught by the ink ribbon transporting means or the like and wrinkles or tears occur, or the ink ribbon 4 is transported during recording. There is a problem that unevenness occurs and an image formed on the recording paper 6 has uneven density.

Therefore, when the thermal head 5 returns to the standby position, the supply roll 2 is rotated in the clockwise direction (arrow C direction) in FIG. 2 by the ink ribbon conveying means to rewind the ink ribbon 4. There is one in which the ink ribbon 4 is surely stored in the ink cartridge 1 during standby.

[0009]

However, even if the ink ribbon 4 is rewound when the thermal head 5 returns to the standby position, the thermal head 5 moving from the standby position to the recording position moves the ink cartridge 1 out of the ink ribbon 1. When pulling out 4, the ink ribbon 4 is excessively pulled out due to the inertia of the supply roll 2 or the winding roll 3, and the thermal head 5 and the platen roller 7
The ink ribbon 4 when pressed against the recording paper 6 by
Looseness occurs. Therefore, when recording, the ink ribbon 4
However, there is a problem in that the unevenness in density occurs in the image formed on the recording paper 6 due to the unevenness in conveyance.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a thermal transfer printer which does not cause slack in the ink ribbon even when the thermal head moves to a recording position.

[0011]

SUMMARY OF THE INVENTION According to the present invention, there is provided an ink cartridge in which an ink ribbon having a thermally transferable ink is mounted between a supply roll and a take-up roll, and an ink used by driving the take-up roll. Winding roll driving means for winding the ribbon around the winding roll, winding roll reverse rotation preventing means for preventing the ink ribbon from being pulled out from the winding roll,
Ink ribbon conveying means provided with a supply roll driving means for driving the supply roll to rewind an unused ink ribbon to the supply roll, a thermal head for heating the ink and transferring it to the recording means, the ink ribbon and the recording means And a platen roller for pressing the thermal head to the thermal head. When the thermal head and the platen roller are pressed against each other, the supply roll driving means is driven so that the ink ribbon is in contact with the thermal head. When the thermal head and the platen roller are tensioned between the take-up roll and the thermal head and the platen roller are separated from each other, the supply roll driving means is driven to store the ink ribbon in the ink cartridge.

[0012]

According to the present invention, when the thermal head and the platen roller are pressed against each other, the ink ribbon is stretched between the supply roll and the take-up roll while being in contact with the thermal head. Recording defects such as image density unevenness due to ink ribbon transport unevenness are eliminated.

Further, since the ink ribbon is housed in the ink cartridge when the thermal head and the platen roller are separated from each other, the ink ribbon is not caught by the ink ribbon carrying means when the ink cartridge is removed from the ink ribbon carrying means. As a result, wrinkles and tears do not occur.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows the construction of an embodiment of the ink ribbon transporting means of the present invention. The same reference numerals as those in FIGS. 2 and 3 designate the same parts, and 8
Is a motor serving as a drive source, 9 is a worm integrally provided on the rotating shaft of the motor 8, 10 is a worm gear that meshes with the worm 9, 11 is a spur gear that is coaxially and integrally provided with the worm gear 10 and has a two-stage structure, Reference numeral 12 is an arm pivotally supported by a common rotary shaft of the worm gear 10 and spur gear 11, and 13 is a spur gear pivotally supported by a rotary shaft at the tip of the arm 12 so as to mesh with the spur gear 11. Reference numeral 13 denotes a differential gear mechanism composed of a spur gear 11 and an arm 12. When the worm gear 10 and the spur gear 11 rotate clockwise in the figure, the arm 12 rotates in the direction of arrow D, When the gear 13 rotates clockwise and the worm gear 10 and the spur gear 11 rotate counterclockwise in the figure, the arm 12 rotates in the direction of arrow E and the spur gear 13 moves counterclockwise. Rotate. 14 and 15 are two-stage spur gears that are coaxially and integrally provided, and the spur gear 14 is an arm 12
Is arranged at a position where it meshes with the spur gear 13 when it rotates in the direction of arrow D. 16 is a winding shaft that engages with the winding roll 3.
Spur gears mounted integrally on 17; 18 spur gears 15 and 16
A spur gear that meshes with and 19 is a stopper pivotally supported by the rotating shaft of the spur gear 18, and the tip of this stopper 19 is meshed with the spur gear 16. A spur gear 20 is attached to a supply shaft 21 that engages with the supply roll 2 via a torque limiter (not shown). The spur gear 20 meshes with the spur gear 13 when the arm 12 rotates in the arrow E direction. It is arranged in a position.

Next, the operation of the embodiment constructed as described above will be described.

First, when a print command is input to the thermal transfer printer and the recording paper 6 is fed from the paper feed tray (not shown) or the like to the right direction (arrow A direction) in FIG. 2 by the paper feed roller (not shown). At the same time, the motor 8 rotates clockwise (however, when the right side surface of the motor 8 is viewed in FIG. 1). Then, the worm gear 10 and the spur gears 11 and 13 rotate clockwise in FIG. 1, the arm 12 rotates in the clockwise direction (arrow D direction) in FIG. 1, and the spur gear 13 meshes with the spur gear 14. . Therefore, the rotation of the motor 8 is transmitted to the take-up shaft 17 via the worm 9, the worm gear 10, the spur gears 11, 13, 14, 15, 18 and 16, so that the take-up roll 3 is rotated counterclockwise in FIG. Since the ink ribbon 4 rotates in the direction (arrow B direction), the ink ribbon 4 is wound around the winding roll 3. Then, when the detection means (not shown) detects the print start position of the ink ribbon 4, the rotation of the motor 8 is stopped and the winding of the ink ribbon 4 around the winding roll 3 is also stopped.

Next, when the recording paper 6 is carried in from the right direction (direction of arrow A) in FIG. 2 to a predetermined position of the platen roller 7, the thermal head 5 descends to the recording position, and the thermal head 5 and the ink. At the same time when the ribbon 4 and the recording paper 6 are pressed against the platen roller 7, the motor 8 rotates counterclockwise for a certain period of time (however, when the right side surface of the motor 8 is viewed in FIG. 1). Then, the worm gear 10 and the spur gear
While 11 and 13 rotate counterclockwise in FIG. 1, the arm 12 rotates in the counterclockwise direction (arrow E direction) in FIG.
Meshes with spur gear 20. Therefore, the rotation of the motor 8 is transmitted to the supply shaft 21 via the worm 9, the worm gear 10, the spur gears 11, 13 and 20, and the supply roll 2 rotates in the clockwise direction (direction of arrow C) in FIG. Therefore, the ink ribbon 4 is
It is wound around the supply roll 2 and is stretched between the supply roll 2 and the winding roll 3 while being in contact with the thermal head 5.

By the way, the torque set in the torque limiter (not shown) mounted between the spur gear 20 and the supply shaft 21 is applied to the ink cartridge 1 by the thermal head 5.
Since the torque is sufficiently smaller than the torque generated in the supply shaft 21 when the ink ribbon 4 is pulled out from the printer, the tension of the ink ribbon 4 does not hinder the movement of the thermal head 5 from the standby position to the recording position.

When the ink ribbon 4 is wound around the supply roll 2, the take-up roll 3 also tries to rotate in the direction opposite to the arrow B direction, but the spur gear 16 bites the tip of the stopper 19, Since the rotation of the take-up roll 3 is immediately stopped, the printing start position of the ink ribbon 4 does not shift due to excessive rewinding of the ink ribbon 4.

As a result, when the thermal head 5, the ink ribbon 4 and the recording paper 6 are pressed against the platen roller 7, the ink ribbon 4 is stretched between the supply roll 2 and the take-up roll 3 and the ink The deviation of the printing start position of the ink ribbon 4 due to excessive rewinding of the ribbon 4 is eliminated, and recording defects such as density unevenness of the image due to unevenness of conveyance of the ink ribbon 4 are eliminated.

When recording is started, the motor 8 rotates in the clockwise direction (however, when the right side surface of the motor 8 is viewed in FIG. 1), the take-up shaft 17 moves in the opposite direction of FIG. The used ink ribbon 4 in which the ink is transferred to the recording paper by the thermal head 5 is rotated in the clockwise direction (the direction of arrow B) and is sequentially wound around the winding roll 3.

When the recording is completed, the thermal head 5 returns to the standby position and is separated from the platen roller 7, and the recording paper 6 is ejected from the platen roller 7. At the same time, the motor 8 rotates in the counterclockwise direction for a certain period of time (however, when the right side surface of the motor 8 is viewed in FIG. 1), the supply shaft 21 moves in the clockwise direction (arrow C direction) in FIG. 1 as described above. As it rotates, the loosened ink ribbon 4 is wound around the supply roll 2 and stored in the ink cartridge 1.

In this embodiment, when the rotation direction of the motor 8 is clockwise, the ink ribbon 4 is conveyed in the forward direction, and when the rotation direction is counterclockwise, the ink ribbon 4 is rotated.
However, the same effect can be obtained even if the rotation direction of the motor 8 is reversed by changing the advancing directions of the worm 9 and the worm gear 10.

Further, in the present embodiment, when the ink ribbon 4 is wound around the supply roll 2, the stopper 19 is used as the spur gear 16.
Although the description has been given of the example in which the reverse rotation of the take-up roll 3 is prevented by making it bite into, the same effect can be obtained by interposing a one-way clutch between the spur gear 16 and the take-up shaft 17.

[0025]

As described above, according to the present invention,
When the thermal head and the platen roller are pressed against each other, the ink ribbon is stretched between the supply roll and the take-up roll while being in contact with the thermal head. This has the effect of eliminating recording defects such as density unevenness.

Further, since the ink ribbon is housed in the ink cartridge when the thermal head and the platen roller are separated from each other, when the ink cartridge is removed from the ink ribbon carrying means, the ink ribbon does not get caught in the ink ribbon carrying means. As a result, there is an effect that wrinkles and tears do not occur.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of an ink ribbon carrying means of the present invention.

FIG. 2 is a diagram showing a basic configuration and operation of a conventional thermal transfer printer.

FIG. 3 is a diagram showing a basic configuration and operation of a conventional thermal transfer printer.

[Explanation of symbols]

1 ... Ink cartridge, 2 ... Supply roll, 3 ... Winding roll, 4 ... Ink ribbon, 5 ... Thermal head, 6 ... Recording paper, 7 ... Platen roller, 8 ... Motor, 9 ... Worm, 10 ... Worm gear, 11 ,13,
14, 15, 16, 18, 20, ... Spur gears, 12 ... Arms, 17 ... Winding shafts, 19 ... Stoppers, 21 ... Supply shafts.

Claims (2)

[Claims] 1. An ink cartridge in which an ink ribbon having a heat transferable ink is mounted between a supply roll and a take-up roll, and the used roll is driven by driving the take-up roll. Winding roll driving means for winding the ink ribbon, winding roll reverse rotation preventing means for preventing the ink ribbon from being pulled out from the winding roll, and driving the supply roll to supply the unused ink ribbon. Ink ribbon conveying means provided with a supply roll driving means for rewinding to a roll, a thermal head for heating the ink and transferring it to the recording means, and a platen roller for pressing the ink ribbon and the recording means onto the thermal head And the drive of the supply roll when the thermal head and the platen roller are pressed against each other. When driving the step, the ink ribbon is stretched between the supply roll and the take-up roll in a state of being in contact with the thermal head, and when the thermal head and the platen roller are separated from each other, A thermal transfer printer, characterized in that the ink ribbon is housed in the ink cartridge by driving a supply roll driving means. 2. The thermal transfer printer according to claim 1, wherein the supply roll driving means is provided with a torque limiter.