JPS6394871A - Up/down driving method of thermal head - Google Patents

Abstract

PURPOSE:To eliminate the slack of an ink ribbon during headup and to prevent contamination of sheet due to shifting of the ink ribbon during headup and headdown, by setting the headdown speed of a thermal head lower than the headup speed. CONSTITUTION:In the way of headup, a gap S is produced instantaneously between a thermal head 4 and an ink ribbon 10. Since levers 23, 24 are swing by the force of a spring 25 corresponding to the headup and guide rollers 26, 27 rotate to apply tensile force onto the ink ribbon 10, the slack of the ink ribbon is adsorbed reliably. Headdown is carried out with lower speed than that for headup, where the motion of the thermal head 4 caused rewinding of the ink ribbon 10 and energization of a ribbon tensioner, withereby the ink ribbon 10 is continuously subject to tensile force and causes no loosening. Furthermore, the headup speed is set sufficiently high, so as to eliminate contamination of sheet due to rubbing or shifting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for driving a thermal head up and down in a thermal transfer recording device.

[Prior art]

There are various types of recording devices such as printers and facsimile machines, such as an inkjet type, a wire dot type, and a thermal type.

Thermal methods include a thermal transfer method that uses an ordinary sheet and performs transfer recording via an ink ribbon, and a thermal method that uses a heat-sensitive sheet and records by heating it to develop color.

With this thermal type, recording is performed while sliding the recording head (thermal head) in pressure contact with the sheet.
Therefore, the thermal head is mounted so as to be driven to swing (up-down drive) between a down position where it is in pressure contact with the sheet and an up position where it is away from the sheet.

FIG. 1 shows a schematic configuration of a thermal transfer recording apparatus.

In FIG. 1, a recording head (thermal head) 4 mounted on a carriage 3 records on a sheet 2 backed up by a platen roller 1.

The carriage 3 is movably mounted along a guide shaft 5 installed parallel to the platen roller 1, and is connected to a stamping motor 6, a driving pulley 7, a driven pulley 8, and these pulleys, and is coupled to the carriage 3. It is reciprocated by a drive system consisting of a belt 9.

The thermal head 4 has a plurality of heating elements (for example, 32 x 2 elements arranged in two vertical rows or 32 resistors arranged in one row of side tabs), and is in a down position where it is pressed against the sheet 2. and is driven to oscillate between the amplifier positions that are separated from each other.

An ink ribbon cassette 11 for supplying an ink ribbon 10 to the front surface of the thermal head 4 is mounted on the carriage 3.

During recording, each heating element is driven based on a data signal, and the thermal head 4 is moved in a press-contact state to record while winding and driving the ink ribbon 10, and the sheet 2 is conveyed in a predetermined pinch direction in the direction of arrow P. A new line is created by doing this.

By the way, in the conventional ink ribbon cassette 11, as shown in FIG. 2, when the carriage 3 stops after recording and the thermal head 4 heads up, the ink ribbon 10 that was recording becomes slack in front of the printer 4. It's gone.

If this slack exists, the leading end of the sheet 2 collides with the ink ribbon 10 when the sheet 2 is inserted, resulting in a jam.

Therefore, after the head is raised, it is necessary to perform an extra operation to tension the ink ribbon 10 in front of the thermal head 4, as shown in FIG. 3, by moving the carriage or driving the ribbon winding remoter.

Therefore, the inventor of the present invention proposed providing spring-biased ribbon tensioners on both sides of the thermal head as a means to automatically remove the slack of the ink ribbon when the head is up and obtain the desired tension (patent application Showa 6l-0234
38).

〔the purpose〕

An object of the present invention is to further develop the above-mentioned invention in which a ribbon tensioner is provided, and to provide a method for driving a thermal head up and down, which can more reliably prevent the ink ribbon from sagging or shifting when the head is up or down. It is to be.

[Means to achieve the purpose]

The present invention provides a thermal transfer recording device that performs transfer recording on a recording sheet via an ink ribbon using a thermal head.
The above object is achieved by an up-down drive method in which the speed at which the thermal head is moved down is set lower than the speed at which it is moved up.

〔Example〕

The present invention will be specifically described below with reference to FIGS. 4 to 6.

The present invention is a method for up-down driving a thermal head of a thermal transfer recording device equipped with a ribbon tensioner.
An example of the configuration of a ribbon tensioner suitable for carrying out the method of the present invention will be described with reference to FIG.

In FIG. 4, a pair of levers 23.24 are provided at substantially symmetrical positions on the left and right sides of the thermal head 4, each independently swingable about a shaft 21.22, and these levers 23.24 are supported by springs. 25 in the direction indicated by the arrow in FIG. 4, the left lever 23 is urged counterclockwise, and the right lever 24 is urged clockwise with appropriate spring force.

Rotatable guide rollers 26 and 27 for guiding the ink ribbon 10 are pivotally supported on the left and right levers 22 and 23.

The present invention is characterized in that when driving the thermal head 4 up and down using such a ribbon tensioner, the speed at which the head of the No. 4 head is moved down is set lower than the speed at which the head is moved up. More preferably, the speed at which the head is moved up and down is set faster than the return speed of the ribbon tensioner.

4 to 6 show plane views of the main parts of a thermal transfer recording apparatus implementing the method of the present invention. FIG. 4 shows the state during the recording operation, FIG. 6 shows the state after the head-up shown in FIG. 5, respectively.

During the recording operation shown in FIG. 4, the thermal printer 4 is in pressure contact with the sheet 2 on the platen 1 via the ink ribbon 10, and moves the carriage 3 (FIG. 1) in the direction of arrow A and approximately in the same direction. - The ink ribbon 10 is wound up in the opposite direction of arrow B at a speed of -

In synchronization with this movement, the dot forming means consisting of a plurality of heating elements provided on the front surface of the thermal head 4 is driven to generate heat based on the recorded information (print data signal), and the ink on the ink ribbon 10 is melted. The image is recorded while being transferred onto the sheet 2.

The ink ribbon cassette 11 is provided with the aforementioned ribbon tensioner. That is, levers 23, 24 are provided on both sides of the thermal head 4 and can be independently swung about their respective shafts 21, 22.
A rotatable guide roller 26,27 for guiding the ink ribbon 10 is provided at the tip of each lever 23.24.
An ink ribbon tensioner is provided which biases each lever 23, 24 so that each guide roller 26, 27 presses the ink ribbon 10 by a tension spring 25 stretched between the ink ribbons 24, 24.

The head-up and head-down operations of the thermal head 4 are performed by driving a motor, and a motor whose speed can be easily controlled, such as a stevening motor, is used as the motor.

However, in the up-down drive method according to the present invention, the speed at which the thermal head 4 is moved down is set lower than the speed at which it is moved up.

More preferably, the speed at which the hend-up is performed is set higher than the return speed of the ribbon tensioner described above, that is, the return speed of the levers 23 and 24 due to the spring force of the spring 25.

FIG. 5 shows the state at the moment of head-up, and FIG. 6 shows the state in which the ribbon tensioner has returned after the hend-up.

That is, since the speed at which the motor drives the head up is set higher than the ribbon tensioner return speed, the gap S between the thermal head 4 and the ink ribbon 10 instantaneously increases during head up as shown in FIG.
occurs.

However, since the ribbon tensioner also operates with a slight time difference in response to the head-up, as shown in FIG. A desired tension is applied to the ink ribbon 10 immediately and effortlessly while rotating, so that the slack in the ink ribbon 10 in front of the thermal head 4 is immediately and reliably absorbed.

When the head is down, it is performed at a speed lower than the speed at which the head amp is performed. In this head-down operation, the ink ribbon 10 is unwound by the movement of the thermal head 4 and the ribbon tensioner is energized by the ink ribbon, so that tension is always applied to the ink ribbon 10 and no loosening occurs.

In this way, a method for driving the thermal head up and down that can reliably eliminate the occurrence of slack in the ink ribbon 10 not only when the head is down but also when the head is up can be obtained using a simple method.

Therefore, it is possible to eliminate unnecessary operations such as winding up the ink ribbon to prevent collision between the sheet and the ink ribbon when inserting the sheet.

Furthermore, since the head amplifier speed is set sufficiently high to raise the head at a speed greater than the return speed of the ribbon tensioner, it is possible to eliminate sheet stains caused by rubbing or shifting of the ink ribbon 10 that occurs at the moment when the thermal head 4 and the sheet 2 are separated. Ta.

In addition, since the head-down speed can be set sufficiently small regardless of the head-up speed, it is possible to eliminate the impact noise caused by the collision of the thermal head 4 when the head is down, and at the same time, the inertia of the thermal head 4 when the head is down can be reduced. It was possible to eliminate stains on the sheet 2 due to friction and displacement of the ink ribbon 10 caused by force (velocity energy).

〔effect〕

As is clear from the above description, according to the present invention, the speed at which the multi-head is brought down is set lower than the speed at which it is brought up. Furthermore, there is provided a method for driving a thermal head up and down, which can reliably prevent sheet staining due to displacement of an ink ribbon when the head is down.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part of a thermal transfer recording apparatus suitable for carrying out the method of the present invention, and FIGS. 2 and 3 are partial plan views illustrating the state of loosening of an ink ribbon in front of a conventional thermal head. 4, 5, and 6 are plan views of the thermal head portion sequentially showing head-up operations when carrying out the method of the present invention, respectively. 2------- (recording) sheet, 4 thermal head, 10- ink ribbon, 11- ink ribbon cassette, 23.24 = - lever (ribbon tensioner), 25- spring (ribbon tensioner), 26.27 guide roller (ribbon tensioner). Figure 2

Claims (2)

[Claims] (1) A thermal transfer recording device in which a thermal head performs transfer recording on a recording sheet via an ink ribbon, characterized in that a speed at which the thermal head moves down is set lower than a speed at which the head moves up. Up-down driving method. (2) The method for driving a thermal head up and down according to claim 1, wherein the speed at which the head is raised is faster than the return speed of the ribbon tensioner.