JPS6371384A - Thermal transfer recording apparatus - Google Patents

Abstract

PURPOSE:To always hold desired ribbon tension by correcting the reduction in ribbon tension accompanied by the increase in the take-up quantity of an ink ribbon, by changing the release angle of the ink ribbon and a sheet on the basis of the detection value of the diameter of a core having taken up the used ink ribbon. CONSTITUTION:A lever 32 is pivotally supported by a ribbon cassette 1 in a rotatable manner. The lever 32 has a C-shape and is pivotally supported at the intermediate point thereof by a shaft 31 and one end part 33 of the lever 32 is contacted with the outer peripheral surface of the ink ribbon 4 on a take-up core 3 under pressure by a spring 34 and the other end part 35 thereof is engaged with the ink ribbon 4 after passing a thermal head 5 on the way thereof in a slidable manner. As the take-up quantity of the used ink ribbon 4 increases and the outer diameter R of the taken-up ink ribbon increases, the lever 32 revolves around the shaft 31 in a clockwise direction against the spring 34. By this constitution, the ink ribbon 4 is pulled in the right direction at the engaging part of the end part 35 of the lever 32 and the release angle theta2 with a sheet is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an ink ribbon supply device in a thermal transfer recording device.

[Conventional technology]

The recording methods of recording devices such as printers, facsimile machines, and electronic stamp writers include ink ribbon methods, wire dot methods, and thermal methods. It can be divided into two types: a thermal method, in which the color is developed by heating, and a thermal method is used.

On the other hand, the types of recording devices include serial type, which prints while scanning the sheet with a carriage equipped with a recording head, line print type, which prints one line at a time, and page printing type, which prints one line at a time. There are also print types.

The present invention is directed to a serial type thermal transfer recording device, and relates to an improvement of its ink ribbon supply device.

8 and 9 schematically show a conventional ink ribbon supply device (ribbon cassette).
The figures each show a state in which the number of used ink ribbons has increased and is almost completely wound up.

8 and 9, a supply core 2 and a take-up core 3 are rotatably provided in a ribbon cassette 1, and the ink ribbon 4 on the supply core 2 is moved by winding and driving the take-up core 3. , passes between the thermal head 5 and the serial 6, and is wound onto the winding core 3.

The sheet 6 is backed up by a platen 7,
The thermal head 5 is mounted on a carriage that moves along the platen so as to be able to amplify it down, and the ribbon cassette 1 is mounted on the carriage so that it can be replaced.

Further, the winding core 3 is rotationally driven by a ribbon winding mechanism provided on the carriage.

Note that reference number 8 indicates a leaf spring for preventing the ink ribbon 4 from loosening.

By the way, a friction clutch is provided between the winding core 3 and the ribbon winding mechanism on the carriage.
A constant rotational force TO is transmitted through the friction clutch, and slipping occurs when the winding load exceeds TO.

In such a conventional structure, as long as the amount of used ink ribbon 4 is not too large, a constant tension f is applied to the ink ribbon 4 by a friction clutch as shown in FIG.
o is given, and the ink ribbon 4 is peeled off from the end of the thermal pad 5 by this tension f0.

However, when the amount of used ink ribbon 4 increases and the ribbon diameter R of the winding core 3 increases as shown in FIG. 9, the tension f=T'0/R of the ink ribbon 4 decreases.
The tension f became smaller than the adhesive force F between the ink ribbon 4 and the sheet 6, causing ribbon sagging and deteriorating print quality.

〔the purpose〕

An object of the present invention is to be able to solve such problems in the prior art, and even when the amount of used ink ribbon increases and the wound core diameter increases, the ink can be maintained at a desired tension without causing ribbon loosening. To provide a thermal transfer recording device that can reliably wind up a ribbon.

[Means to achieve the purpose]

The present invention provides a means for detecting the core diameter of a used ink ribbon wound in a thermal transfer recording device equipped with a thermal head, an ink ribbon, and a ribbon winding mechanism on a carriage that moves along a platen. The above object is achieved by a configuration in which the peeling angle of the ink ribbon from the sheet is changed depending on the detected value.

〔Example〕

The present invention will be specifically described below with reference to FIGS. 1 to 7.

FIG. 5 shows a thermal transfer recording apparatus suitable for carrying out the present invention.

In FIG. 5, the apparatus is configured so that a recording head (thermal head) 5 mounted on a carriage 10 records on a recording sheet 6 backed up to a platen 7. Note that the illustrated platen 7 has a roller shape,
Also serves as a sheet feed roller.

The carriage 10 is movably mounted along a guide shaft 11 installed parallel to the platen 7, and is equipped with a stepping motor (carriage drive motor) 12, a drive pulley 13,
It is reciprocated by a drive system consisting of a driven pulley 14 and a timing belt 15 wound around these pulleys and coupled to the carriage 10.

On the carriage 10 is a ribbon cassette 1 for feeding the ink ribbon 4 between the thermal head 5 and the sheet 6.
is attached replaceably.

A printing pattern forming means configured by arranging a plurality of electrothermal transducers such as heating resistors is provided on the front surface of the thermal head 5.
In contrast, the head-down position where the ink ribbon 4 is pressed against the platen 7 via the ink ribbon 4 and the sheet
It is mounted so that it can be oscillated between the head-up position and the retracted head-up position.

Furthermore, when the carriage 10 is moved in the head-down state, the ink ribbon 4 in the ribbon cassette 1 is wound and driven in synchronization with the movement of the carriage.

During recording, the thermal head 5 is moved in a head-down state, the ink ribbon 4 is fed in synchronization with this, and recording is performed while driving the electrothermal transducer of the head based on print data. Sheet 6 is fed one by one in the direction of arrow S to start a new line.

FIG. 6 shows the inside of the ribbon cassette I and the ribbon drive mechanism on the carriage IO with the cassette lid removed.

In FIG. 6, a ribbon shaft 16 having a vertical shaft is rotatably supported on the carriage IO. At the tip (upper end) of this ribbon winding shaft 16, there is a ribbon force set l-1.
An engaging portion 17 is provided that extends inward and engages with the winding core 3 so as to transmit rotational force, and a friction clutch 18 and a gear 20 are provided at the base of the ribbon winding shaft.

Further, a ribbon winding motor (stenting motor) 21 is attached to the carriage lO via a flange 2o.

FIG. 7 shows details of the ink ribbon winding mechanism.

6 and 7, the friction clutch 18 includes a driven member 22 fixed to the ribbon winding shaft 16, a drive member 23 rotatably fitted to the shaft 16, and these members 22. It is composed of a felt-like ring 24 that is frictionally slidably interposed between 23 and a spring 25 for applying frictional rotational force. The drive member 23 also serves as the gear 19, and a pinion 26 provided on the output shaft of the ribbon winding motor 21 meshes with the tooth profile formed around the drive member 23.

Further, the tip engaging portion 17 of the ribbon winding shaft 16 is inserted into the inner diameter portion of the winding core 3 of the cassette l and engaged therewith so as to transmit rotational force.

As shown in FIG. 6, the ribbon cassette 1 is positioned on the carriage 1o with the bin portions 27.27 provided on the left and right sides of the cassette engaged with the groove portions 28.28 provided on the carriage 10. Attached interchangeably.

In the above configuration, recording is performed by placing the thermal head 5 in a head-down state and driving the thermal head based on a print data signal while scanning the sheet 6 with the carriage lo.

During this recording, the ribbon winding motor 21 and the carriage drive motor 12 are driven synchronously, and the ink ribbon 4 is wound up by the same length (distance) in synchronization with the scanning of the carriage 10.

1 to 4 show essential parts of an embodiment of a thermal transfer recording apparatus according to the present invention.

FIG. 1 shows a state where the amount of ribbon taken up by the ink ribbon supply device is small, and FIG. 2 shows a state where the amount of ink ribbon taken up by the device of FIG. 1 is increased.

In FIGS. 1 and 2, a lever 32 is rotatably supported on a shaft 31 provided perpendicularly to the bottom surface of the ribbon cassette 1. As shown in FIG.

As shown in FIGS. 1 to 3, the lever 32 has a dogleg shape, is supported by a shaft 31 at its midpoint, and has one end 33 supported on the winding core 3 by a spring 34. The other end 35 is slidably engaged with the ink ribbon 4 after passing through the thermal head 5 .

The engagement between the end portion 35 and the ink ribbon 4 is carried out by inserting the ink ribbon 4 between two pins 36 and 36 implanted in the end portion.

As shown in FIG. 6, the ink ribbon cassette 1 is replaceably mounted on a carriage 10 and connected to a ribbon winding mechanism on the carriage, and the ink ribbon 4 is attached to a sheet 6 backed up on a platen 7 and a thermal head. A guiding frame is installed between the 5 and 5.

The winding core 3 is synchronized with the scanning movement of the carriage 10.
The ribbon winding remoter 21 (Fig. 7) outputs a constant rotational force TO through the friction clutch 18 (Fig. 7), and as a result, the ink ribbon 4 on the supply core 2 passes through the thermal head 5 and is wound up. It is wound onto core 3.

When the amount of winding of the ink ribbon 4 is small, as shown in FIG. 1, the peeling angle θ of the ink ribbon 4 from the sheet 6, that is, the angle formed by the ink ribbon 4 and the platen at the rear end of the thermal head 5 is θ1. It has become.

As recording is performed and the used ink ribbon 4 is wound around the winding core 3, the winding amount increases, and as the outer diameter of the wound ink ribbon increases, the lever 32 resists the spring 34 and rotates around the shaft 31. Rotate clockwise (clockwise).

As the amount of ribbon winding increases, the ink ribbon 4 is pulled to the right at the engagement part with the end 35 of the lever 32, as shown in FIG. 2, and the peeling angle θ of the ink ribbon becomes the angle shown in FIG. The angle increases from θ1 to become an angle θ2 (θ2>θ1).

FIG. 4 shows the force acting on the peeling portion of the ink ribbon 4. As shown in FIG.

In FIG. 4, if the adhesive force acting between the ink ribbon 4 and the sheet 6 is F, the tension acting on the ink ribbon is r, and the peeling angle is θ, then In order to wind smoothly, the ribbon tension f
It is necessary for the vertical component sin θ of the adhesive force F to be larger than the adhesive force F.

That is, F<fsinΦ Must.

On the other hand, as previously explained with reference to FIG. 9, as the core diameter R of the used ink ribbon increases, the ribbon tension f decreases.

However, according to the configurations shown in FIGS. 1 and 2, the means for detecting the core diameter R around which the used ink ribbon 4 is wound, that is, the lever 32 that rotates according to the core diameter R and changes the ribbon peeling angle θ. Since an adjustment mechanism is installed to increase the ribbon peeling angle θ according to the increase in the core diameter R, it is possible to correct the decrease in ribbon tension due to an increase in the winding amount, and the overall ribbon tension (second f2 in the figure can be maintained at a value that does not change much from the ribbon tension in the initial state (fl in Figure 1).

Therefore, according to the configurations shown in FIGS. 1 to 4, even if the amount of used ink ribbon 4 increases and the wound core diameter R increases, the desired stable tension can be maintained without causing ribbon sagging. A thermal transfer recording device is obtained in which the ink ribbon 4 can be reliably wound up and the deterioration in printing quality due to ribbon sagging can be avoided.

〔effect〕

As is clear from the above description, according to the present invention, the peeling angle of the ink ribbon from the sheet is changed based on the detected value of the core diameter from which the used ink ribbon is wound. A thermal transfer recording device is provided that can eliminate deterioration in printing quality due to ribbon sagging by correcting the decrease in ribbon tension that accompanies the increase and always maintaining a desired ribbon tension.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an ink ribbon supply device of an embodiment of the thermal transfer recording apparatus according to the present invention in a state where the amount of ink ribbon taken up is small, and FIG. 2 is a plan view of the ink ribbon supply device of the apparatus shown in FIG. 3 is a perspective view of the lever in FIG. 1, FIG. 4 is a schematic diagram showing the relationship of forces acting on the ribbon peeling part in FIG. 1, and FIG. 5 is a diagram showing the present invention. FIG. 6 is an exploded perspective view of the ink ribbon supply device of the recording device of FIG. 5, and FIG.
The figure is a longitudinal sectional view of the ribbon winding mechanism shown in Figure 6, Figure 8 is a plan view of a conventional ink ribbon supply device in a state where there is little ribbon winding, and Figure 9 is the amount of ribbon taken up as shown in Figure 8. 71...----- Ribbon cassette, 3-----1-- Winding core, 4
−・・−・Ink ribbon, 5−・−・−11−−−
Thermal head, 6------・---sheet, 7
・−・・・・−・Platen, 10−・−・−・・
−・・Carriage, 32・−・−・−・・−・Lever, θ
・−−−−−−− Ribbon peeling angle, f −−−−−
−・−・−Ribbon tension, R−・−・−・・− Winding core diameter.

Claims (1)

[Claims] (1) In a thermal transfer recording device equipped with a thermal head, an ink ribbon, and a ribbon winding mechanism on a carriage that moves along a platen, a means for detecting the core diameter of a used ink ribbon wound thereon, and a method for detecting the core diameter. A thermal transfer recording device characterized by changing the peeling angle of an ink ribbon from a sheet depending on the value.