JP2704879B2 - Thermal transfer recording method - Google Patents

Description

The present invention relates to a thermal transfer recording method capable of transferring and recording a good image even on a recording medium having low smoothness.

<Prior Art> Today, various recording methods have been developed as input information output devices, and a typical example thereof is a thermal transfer recording method.

In this recording method, generally, an ink ribbon coated with a thermal transfer ink containing wax as a main component and a recording paper are pressed against a platen by a recording head, and in this state, the recording head is selectively heated to apply to an ink sheet. It is used to transfer and record the thermal transfer ink on the recording paper by melting it into an image pattern. It is widely used as an output device such as a word processor or an electronic typewriter because of its small size, light weight, and excellent low noise. .

<Problems to be Solved by the Invention> In the above-mentioned thermal transfer recording method, a difference occurs in image quality depending on the smoothness of the recording paper. Is hard to be sharp.

Therefore, during normal printing, the pressing force of the printing head is set to about 500 gf / cm or less. However, when printing on rough paper, it is considered that the head pressure is increased. However, when the head pressure is increased, the molten ink may spread due to the high head pressure and appear as bleeding of the recorded image, or the molten ink may penetrate deeply into the paper fibers of the recording paper, resulting in insufficient recording density. There was a problem that there were times.

For this reason, in the conventional thermal transfer recording method, it is difficult to set the head pressure by the recording head to about 500 gf / cm or more.

The present invention has been made to solve the above-mentioned conventional problems, and to provide a thermal transfer recording method capable of setting a head pressure high within a certain range and transferring and recording a good image even on a recording medium having low smoothness. It is.

<Means for Solving the Problems> A configuration according to the present invention for solving the above problems is a thermal transfer recording method of selectively heating a thermal transfer medium with a recording head to perform transfer recording on a recording medium, The head pressure at which the recording head presses the platen through the thermal transfer medium and the recording medium during recording is 1100 gf / cm or more and 2500 gf / cm.
It is characterized in that it is set as follows.

<Operation> According to the above-described means, the head pressure during recording is 1100 gf
/ cm or more, the recording medium is elastically deformed, and particularly when ink containing a resin as a main component is used, the high-viscosity ink is adapted to the recording medium and adheres over a wide area. Therefore, it is possible to transfer and record an image having a small ink elongation, almost no image chipping, and a good reproducibility at an edge portion.

<Embodiment> Next, an embodiment in which the above means is applied to a serial type thermal transfer recording system will be described with reference to the drawings.

(First embodiment)

FIG. 1 is an explanatory perspective view of a thermal transfer recording apparatus according to the first embodiment, FIG. 2 is an explanatory sectional view of a thermal transfer medium, and FIG.
FIG. 3B is an explanatory cross-sectional view of a recording unit during non-recording and during recording.

First, an overall schematic configuration will be described. An ink ribbon 2 serving as a transfer recording medium is stored in a cassette 1, and the cassette 1 is removably mounted on a carriage 3. The carriage 3 is configured to be able to reciprocate along a carriage shaft 5 by a drive mechanism 4. When the carriage 3 moves in the direction of arrow A, the ink ribbon 2
The ink ribbon 2 is fed out by a pair of conveying rollers 6 forming the conveying means, and the recording head 7 heats the ink ribbon 2, and a recording medium (plain paper, plastic sheet, etc. The ink is transferred to recording paper 9). Further, the recording paper 9 is configured to be intermittently conveyed line by line by conveying means (not shown).

Next, the configuration of each part will be described in detail. First, the cassette 1 is composed of a lower case 1a and an upper cover 1b. Inside the lower case 1a, an ink ribbon 2 serving as a thermal transfer medium is provided on a supply reel of the cassette 1. Wound on 1c, the supply reel
It is guided from 1c so as to be exposed once by a notch (not shown) of the lower case 1a, and is wound around a take-up reel 1d.

The ink ribbon 2 is obtained by applying a heat transferable (heat melting property, heat softening property, heat sublimation property, etc.) ink in a layer on a support, and preferably contains a resin-containing ink, particularly preferably contains an ionomer resin. Used ink is used. The ionomer resin refers to a resin in which a main chain of a hydrocarbon has a side chain of a carboxyl group partially or completely neutralized with a metal ion or a quaternary ammonium ion. Among the ionomer resins, those obtained by neutralizing a copolymer composed of an α-olefin such as ethylene and propylene and an α, β-unsaturated carboxylic acid with metal ions are used. The content of the ionomer resin in the thermal transfer ink component is 5 to 70%.
Is preferably used.

As shown in FIG. 2, the ink ribbon 2 used in this embodiment has an intermediate layer 2b, a first transfer layer 2c, and a second transfer layer on a support 2a.
2d are sequentially laminated to form a thermal transferable ink layer. Specifically, it is described in Japanese Patent Application No. 62-146380 (filed on Jun. 12, 1987) filed by the present applicant, and uses a polyester film having a thickness of 6 μm as a support 2a. The intermediate layer 2a, the first transfer layer 2c, and the second transfer layer 2d are each formed using the following components.

The carriage 3 is connected to a belt 4c stretched between pulleys 4a and 4b. When a carriage motor 4d connected to the pulley 4a is driven, the carriage 3 is guided by a carriage shaft 5 to reciprocate. Have been.

When the carriage 3 moves in the direction of arrow A in FIG. 3, the conveying roller pair 6 conveys the ink ribbon 2 in the direction of arrow B, and the recording head 7 moves the platen 8 via the ink ribbon 2 and the recording paper 9. The ink ribbon 2 is sequentially fed from the supply reel 1c by sliding while being pressed.

Further, at a predetermined position of the carriage 3, a winding motor 3a provided in the carriage 3 and a friction clutch
A winding shaft 3c connected via 3b is provided, and is configured to rotate in the direction of arrow C in synchronization with the movement of the carriage 3 only during recording (the carriage 3 moves in the direction of arrow A). The friction clutch 3b has a structure in which the torque of the motor 3a is not transmitted to the winding shaft 3c when a predetermined torque or more is applied, and the friction clutch 3b engages the winding reel 1d of the cassette 1 with the winding shaft 3c. By driving the motor 3a, the ink ribbon 2 is wound on the take-up reel 1d by the amount sent from the supply reel 1c.

A cutout 3d is formed on the front surface of the carriage 3 at a position corresponding to the cutout of the lower case 1a, and a recording head 7 is provided at the cutout 3d so as to be swingable in the direction of arrow D.

The recording head 7 is provided with a glaze layer (not shown) on a head substrate 7a, and a plurality of heating elements 7b that conduct and generate heat in accordance with an image signal on the glaze layer. Further, the heating element rows are arranged near the downstream edge of the head substrate 7a in the ink ribbon feeding direction (a so-called edge head). This is the ink ribbon 2 heated by the heating element 7b.
Is removed from the recording paper 9 in a short time of about several milliseconds after heating, so that the ink runs out.

The distance Δx from the end of the heating element 7b to the end of the head substrate 7a is preferably set to about 250 μm or less, and more preferably to 150 μm or less.

In this embodiment, the recording head 7 has a glaze layer thickness of 44 μm, a heating element array having a dot density of 240 dots / inch and a length of 4.65 mm, and a distance Δx from the substrate edge to the heating element array.
The one having a size of 122 μm is used. The length of the recording head 7 pressing the platen 8 is 6 mm.

The recording head 7 is configured to lower the head during recording, press the ink ribbon 2 against the recording paper 9 by pressing means 10 and press the platen 8 at a set pressure.

The platen 8 pressed by the recording head 7 is formed in a flat plate shape. In the present embodiment, a hard rubber having a hardness of 73 degrees is formed in a flat plate shape having a width of 6 mm, and this is mounted on a platen holder 8a. .

Next, as shown in FIGS. 1 to 3, the configuration of the pressing means 10 is such that a bent head arm 10a is rotatably mounted on a bent portion by a shaft 10b, and one end 10a of the head arm 10a is rotated. _The recording head 7 is supported by 1 and a head arm 10
tension spring between the other end 10a _{2 of a} and the pressing arm 10c
10d is installed.

Further, one end of the pressing arm 10c is rotatably mounted on the shaft 10b, and the other end is a tension spring 10f.
, So as to be pressed against the outer periphery of the cam 10e.

Therefore, when the cam 10e is rotated, the recording head 7 moves down and up. When the head is lowered, the spring 10d is pulled, and the recording head 7 presses the platen 8 with a predetermined pressure. The head pressure at this time is preferably set to be in a range of 800 gf / cm or more and 3500 gf / cm or less, more preferably 1100 gf / cm.
/ cm or more and 2500 gf / cm or less, more preferably 1600 gf / cm or more 2
Set to 500gf / cm or less.

The ink ribbon 2 is configured such that the tension on the downstream side in the transport direction of the ink ribbon 2 from the recording head 7, that is, the winding side (hereinafter referred to as “front tension”) can be changed by the tension means 11. The configuration of the tension means 11 is as follows.
The shaft 1b is rotatably mounted on the shaft, and one end thereof is provided with a moving roller 11c, and the other end is provided with a tension spring 11d. Further, the ink ribbon 2 is guided by a guide roller 12 provided on the lower case 1a and a moving roller 11c of the tension arm 11a.
Through to the take-up reel 1d.

Accordingly, the ink ribbon 2 is pulled upward in FIGS. 3A and 3B by the pulling force of the spring 11d, and thus the front tension is applied.

Further, a magnet 11e is attached to the tension arm 11a, and a Hall element 11f is attached to the lower case 1a near the magnet 11e. Thereby, the distance between the magnet 11e and the Hall element 11f, that is, the inclination of the tension arm 11a is detected, and the position of the tension arm 11a is controlled to be constant by controlling the rotation speed of the conveying roller pair 6 during recording. A constant front tension is applied to the ink ribbon 2 so that the ink ribbon 2 is not separated from the recording paper 9 so as not to be delayed.

Next, a recording method in the case where recording is performed using the thermal transfer recording apparatus having the above configuration will be described.

The recording head 7 is moved down, the platen 8 is pressed with a head pressure of 800 gf / cm to 3500 gf / cm via the ink ribbon 2 and the recording paper 9 and the carriage 3 travels in the direction of arrow A in FIG. 3 (B). At the same time, recording is performed by sequentially feeding out the ink ribbon 2 in the direction of arrow B. At this time, the heat transferable ink is melted and adhered to the recording paper 9 by the heat of the heat generating element 7b generated according to the image signal. This molten ink has high viscosity due to its main component of resin, but the head pressure is 800g
Since the f / cm is as high as 3500 gf / cm, the fibers of the recording paper 9 are elastically deformed, and the high-viscosity molten ink is adapted along the fibers and adheres with a wide contact area.

Therefore, when the molten ink and the non-molten ink break when the ink ribbon 2 is peeled from the recording paper 9, the length of the molten ink extending (extending like a syrup) is reduced. In addition, transfer defects in the image edge portion hardly occur, and a high-quality image with a sharp image edge can be obtained.

If the head pressure is excessively increased (not less than the set head pressure), the recording paper 9 is damaged, and the molten ink penetrates deeply into the fibers of the recording paper 9, which is not preferable because the image density is reduced.

Next, an experimental result of performing thermal transfer recording by using the above-described thermal transfer recording apparatus while changing the head pressure will be described.

The following three types of recording paper 9 are subjected to recording with a common test pattern by dividing the head pressure into nine steps as follows, and (1) the sharpness of the edge portion in the transferred image at that time;
(2) Length of ink extension, (3) Ink density, (4)
Each of the recording papers was examined for damage.

(1) Sharpness of edge portion in transferred image The results of subjective evaluation of the sharpness of the edge portion of the transferred image when recorded on bond paper A at the respective head pressures are as shown in FIG. there were. The evaluation shown in FIG. 4 was performed when the head pressure was 1167 gf / cm (700 gf) and the evaluation was 3, and when the head pressure was 2500 gf / cm (1500 gf), the evaluation was 4.

As is clear from FIG. 4, the sharpness of the edge portion of the image sharply improves from a head pressure of around 833 gf / cm (500 gf), and the image quality is remarkably improved around 1167 gf / cm (700 gf). At 1667 gf / cm (1000 gf), the image quality was further improved. The image quality did not change much even when the head pressure was further increased, and the improvement of the image quality reached a saturation range around 2500 gf / cm (1500 gf).

 The evaluation was common to other recording papers.

(2) Length of ink extension It is considered that the sharpness of the edge portion of the transferred image is greatly affected by the extension of the molten ink. Then, for the bond paper A, the length of extension of the ink with respect to the head pressure (the length extending like a syrup at the moment when the molten ink breaks from the non-molten ink) was observed with a high-speed video. The result is shown in FIG. It was as shown.

4 and 5, there is a correlation between the length of ink extension and the sharpness of the image edge portion. If the ink extension is long, the sharpness decreases and the image quality deteriorates. It can be seen that when the ink spread is short, the sharpness is increased and the image quality is improved.

The length of the ink extended slightly varied depending on the smoothness of the recording paper, but the tendency with respect to the head pressure was common to all three types of recording paper.

(3) Ink Density Recording was performed on the bond paper A at each of the above head pressures, and the result of a subjective evaluation of the ink density of the transferred image was as shown in FIG. The evaluation shown in FIG. 6 was performed when the head pressure was 1167 gf / cm (700 gf) and the evaluation was 4.

As is apparent from FIG. 6, the head pressure was 2500 gf
/ cm (1500gf) or more, paper fiber appears on the surface,
The phenomenon that the apparent ink density was reduced occurred.

(4) Damage to the recording paper The recording was performed on each recording paper with the respective head pressures, and it was checked whether or not each recording paper was damaged.
No damage was observed on each recording paper up to gf / cm (1500 gf).

Even when the head pressure was 3333 gf / cm (2000 gf), no damage was observed in the bond papers A and B, but slight deterioration was observed in the embossed paper.

Further increasing the head pressure to 3833gf / cm (2300gf)
Degradation was observed for each recording paper.

(5) Comprehensive Evaluation The above evaluations (1) to (4) can be evaluated as shown in FIG.

As is clear from FIG. 7, when the head pressure is set at 800 gf / cm or more and 3500 gf / cm or less with respect to the heating element row, a good transfer image can be obtained even on a recording paper having a low surface smoothness. Recognize.

Further, when the head pressure is set in the range of 1100 gf / cm or more and 2500 gf / cm or less, it can be seen that a considerably good transferred image including the image density can be obtained.

Further, it can be seen that the best transferred image can be obtained when the head pressure is set at 1600 gf / cm or more and 2500 gf / cm or less.

In this embodiment, as described above, a good transfer image can be obtained even on a low-smoothness recording paper by setting the head pressure high within a certain range and thermally transferring the resin-based thermal transfer ink. Can do that.

[Other embodiments]

When performing recording by setting the head pressure as described above, it is preferable to use an ink containing a resin as a main component as the thermal transfer ink to be used, and the resin component of the ink used in the first embodiment is used. However, the present invention is not limited thereto, and for example, an acrylic resin, a low molecular weight polyester resin, a urethane resin, a styrene acrylic resin, and a polyamide resin can also be suitably used.

As the support, not only the polyethylene film used in the first embodiment described above but also a polyethylene terephthalate film or the like can be suitably used.

<Effects of the Invention> As described above, the present invention sets not only a high smoothness recording medium but also a low smoothness recording medium by setting the head pressure by a recording head to be high in a certain range during thermal transfer recording. However, a good image can be transferred and recorded.

Further, by using a thermal transfer medium containing a resin at the time of the recording, the quality of a transferred image can be more effectively improved.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of a thermal transfer recording apparatus according to one embodiment of the present invention, FIG. 2 is an explanatory view of a configuration of an ink ribbon, and FIGS. FIG. 4 is a graph showing the evaluation of the sharpness of the edge portion in the transferred image with respect to the head pressure, FIG. 5 is a graph showing the ink spreading, FIG. 6 is a graph showing the ink density, and FIG. 5 is a graph showing the overall evaluation of a transferred image with respect to pressure. 1 is a cassette, 1a is a lower case, 1b is an upper cover, 1c is a supply reel, 1d is a take-up reel, 2 is an ink ribbon, 3 is a carriage, 3a is a take-up motor, 3b is a friction clutch, and 3c is a take-up shaft. 4 is a drive mechanism, 4a and 4b are pulleys, 4c is a belt, 4d is a carriage motor, 5 is a carriage shaft,
6 is a conveying roller pair, 7 is a recording head, 7a is a substrate, 7b is a heating element, 8 is a platen, 8a is a platen holder, 9 is a recording sheet, 10 is pressing means, 10a is a head arm, 10b is a shaft, and 10c is a shaft. Pressing arm, 10d is tension spring, 10e
Is a cam, 10f is a tension spring, 11 is a tension means, 11a is a tension arm, 11b is a shaft, 11c is a moving roller, 11d is a tension spring, 11e is a magnet, 11f
Is a Hall element and 12 is a guide roller.

(72) Inventor Nobuyuki Kuwahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yasuyuki Tamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Tadashi Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshihiko 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Inside Canon Inc. (56) Reference Document JP-A-1-182066 (JP, A) JP-A-1-221263 (JP, A) JP-A-62-28267 (JP, A) JP-A-62-169684 (JP, A) 29438 (JP, U) Actually open sho 61-170565 (JP, U)

Claims (3)

(57) [Claims] 1. A thermal transfer recording method in which a thermal transfer medium is selectively heated by a recording head to perform transfer recording on a recording medium, wherein the recording head controls a platen via the thermal transfer medium and the recording medium during recording. A thermal transfer recording method characterized in that the pressure of the head to be pressed is set to 1100 gf / cm or more and 2500 gf / cm or less. 2. A thermal transfer recording method in which a thermal transfer medium is selectively heated by a recording head to perform transfer recording on a recording medium, wherein the recording head controls a platen via the thermal transfer medium and the recording medium during recording. A thermal transfer recording method characterized in that the pressure of the head to be pressed is set to 1600 gf / cm or more and 2500 gf / cm or less. 3. The thermal transfer recording method according to claim 1, wherein a thermal transfer ink containing a resin is used as the thermal transfer medium.