JPH01238960A - Electrothermal transfer recorder - Google Patents

Abstract

PURPOSE:To enable a gradation image which is good in energy efficiency to be recorded at a high speed by a method wherein a recording head in which a distance from each recording electrode to a common electrode is made to be not more than one half of a pitch P in a main scanning direction of the recording electrode is used, and an ink ribbon of two layer structure of a resistance layer and an ink layer is used. CONSTITUTION:A distance between each recording electrode 7 of a recording head 13 and a common electrode 7 is so arranged as to be not more than one half of a pitch P between a plurality of adjacent recording electrodes 6. Thus, a current having flowed from the recording electrode 6 flows into the common electrode 7 spreading not widely in a main scanning direction. Therefore, when an ink ribbon of a two layer type composed of a resistance layer 1 and an ink layer 3 is used, a current flows through the resistance layer between the recording electrode 6 and the common electrode 7, and the whole resistance layer between those are heated. Therefore, highspeed recording will be able to be performed. Further, by varying time to be applied to each recording electrode 6 while a recording head 5 is being moved in a sub scanning direction, a length in the sub scanning direction of a picture dot to be recorded can be regulated, and gradation recording by using ink suitable for binary recording can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrical transfer recording device capable of realizing gradation images.

(Prior Art) An electric transfer recording device uses heat to soften, melt, or sublimate ink applied to an ink ribbon, and then prints the ink onto a recording medium that is pressed against the ink layer of the ink ribbon.
It is a type of thermal transfer recording device that forms an image by transferring or diffusing this ink. A normal thermal transfer recording device uses a heating element such as a thermal head to generate heat and heats the ink ribbon from the base film side of the ink ribbon using the thermal head. However, in an electric transfer recording device, the ink ribbon itself generates heat to generate ink. The difference is that it is heated. In other words,
In an electric transfer recording device, heat is generated right next to the ink, so the heat transfer efficiency to the ink is good, and since the recording head does not generate heat, there is no heat accumulation in the recording head. The head does not generate heat, so there is no risk of damaging the head, and a large amount of recording energy can be supplied.The heat generating point on the ink ribbon is constantly moving, so direct current is possible. . Therefore, compared to conventional thermal transfer recording devices, it is possible to record at high speeds, and it is also possible to record on rough paper using rough paper ink with a high melting point, and to record gradation images at high speed using sublimation ink. becomes.

FIG. 5 is an explanatory diagram showing the principle of the electrical transfer recording apparatus. In this current transfer recording device, a resistive layer (■), a conductive layer (■),
The ink ribbon (A) is composed of three layers of ink layer ■, and the recording electrodes (Q and common electrode ■) provided on the recording head ■ are pressed against the resistance layer ω side of the ink ribbon (A). Then, depending on the image data supplied from the pattern generation circuit, recording electrode 0 is selectively changed to recording electrode ■.
A current (c) (indicated by the arrow in the figure) is flowing through the resistive layer ■ → conductive layer ■ → resistive layer ■ → common electrode ■. This current (8)
The ink in the ink layer ■ is heated by the Joule heat generated when the ink flows through the resistance layer ■, and this ink is transferred to the recording medium (
9) to form an image. Note that the contact area between the recording type Vii■ and the resistive layer ■ is sufficiently large compared to the contact area between the common electrode ■ and the resistive layer ■, and the distance between the recording electrode ■ and the common electrode ■ is also adjacent. Since the pitch is sufficiently large compared to the pitch of the recording electrodes (■), when current flows from the conductive layer (■) to the common electrode (■), it also passes through the resistive layer (■), but here the ink of the ink layer (3) is No large amount of heat is generated. In addition to the above-mentioned characteristics, such an electric transfer recording device has the following characteristics: By making the electrode pitch smaller than the electrode pitch in the direction in which the rows are arranged (in the figure, the direction perpendicular to the plane of the paper), it is possible to increase the resolution in the sub-scanning direction. This situation is shown in FIG. 5(b). As shown in this figure, when a recording electrode with a width (W) that is sufficiently small compared to the pitch (P) of the recording electrode is moved in the sub-scanning direction and the energization time is changed, the length of the recording electrode increases in the sub-scanning direction. Pixel points of different sizes are formed. In other words, by changing the current application time, the resolution in the sub-scanning direction can be changed arbitrarily, regardless of the recording electrode pitch. In other words, this shows that even with an electric transfer recording device that originally performs binary recording, gradation recording can be performed by changing the area of a pixel within one pixel.

Although the current transfer recording device has such characteristics, there are some possible drawbacks. First of all, since the ink ribbon has a complicated structure, the cost of the ink ribbon increases. In particular, the conductive layer (2) has full bends such as Aj2 attached by vapor deposition, which is a factor in increasing the cost. This becomes a particularly serious problem in the case of a recording apparatus using a line-type recording head, such as a video printer. In order to solve this problem, the sixth
An electrical transfer recording device using an ink ribbon (as shown in the figure) consisting of only a resistive layer (1) and an ink layer (2) has also been proposed.

In this case, the current flows along the path of electrode 0 → resistance layer (2) → common electrode (2).

In this case as well, since the current is concentrated only directly below the recording electrode 0, the image is formed near the recording electrode 0.

A second drawback of these current transfer recording devices is that a large amount of energy is consumed and used for purposes other than recording. In the case of the conventional example shown in Fig. 6, the conductive layer ■
When current flows from the conductive layer (2) to the common electrode (2), the energy consumed by the resistance of the resistive layer (2) becomes energy loss. Further, these losses have the disadvantage that the larger the number of electrodes driven simultaneously, the more current flows through the conductive layer, so that these losses become even larger. For example, in a serial printer with 40 recording electrodes with a recording electrode pitch of 10 dots/1 nch, 1
When only one recording electrode is driven, more than 95% of the supplied energy is used for recording, whereas when 40 recording electrodes are driven simultaneously, the loss increases to about 60%.

These drawbacks can be solved by using the 6th ink ribbon, which lowers the cost of the ink ribbon.
This is a drawback that the conventional example shown in the figure also has. In other words,
All that is necessary for recording is heat generation near the recording electrode ■, but in reality, the current (c) flows through the resistance layer ■ toward the common electrode ■, so a large loss occurs here. It's hidden away.

In order to solve the above-mentioned problems, an electric transfer recording apparatus as shown in FIG. 7 has been proposed.

In this example, the distance between the recording electrode ■ and the common electrode ■ is approximately the same as the recording electrode pitch, and the distance between the recording electrode ■ and the common electrode ■ is approximately the same as the recording electrode pitch.
This is a method in which the entire resistor M1 between the two is heated to record one pixel. With this method, almost no energy is lost, making it possible to realize an efficient electrical transfer recording device. However, the disadvantages of this method are that it is impossible to drive all recording electrodes simultaneously due to crosstalk, and although it is suitable for binary images, it is not suitable for recording gradation images. Sometimes.

First, regarding the problem of crosstalk, as shown in Figure 7(b), this figure shows the crosstalk when viewed from the direction of arrow B.
This is a diagram showing the relationship between recording electrodes (0, common electrode (2), resistance layer (2), and current (8).0 For example, as shown in this figure, recording electrodes (6-1) and (6-3).

Consider (6-5) and the case where only the odd numbered electrodes are driven.

In this case, the current (c) flowing from the recording electrode spreads as shown in the figure, and the current flowing out from the recording electrode (6-2), (6-4), and (6-6), which is not originally necessary for recording, spreads as shown in the figure. Current also flows through these parts, and if the heat accumulation phenomenon increases as the speed increases, image dots will also be formed in these unnecessary parts. Furthermore, small mechanical factors such as uneven feeding of the recording head may cause these pixels to be recorded, resulting in unstable recording. In order to eliminate these instabilities, it is difficult to increase the recording speed beyond a certain level, which goes against the current technological trend of pursuing high-speed recording.

Further, in this method, the width of the formed pixel in the sub-scanning direction and the width in the main scanning direction are approximately equal.

Therefore, it is suitable for recording binary images.

It is also possible to record gradation images when using ink that can record dots with a density proportional to the amount of recording energy, such as thermal sublimation, but
Gradation recording using value-recorded inks has had the disadvantage of being unsuitable.

(Problems to be Solved by the Invention) As mentioned above, the conventional methods have some advantages, but they all have good recording energy efficiency, are capable of high-speed recording without crosstalk, and are capable of recording gradation. Nothing that could have been realized had been realized.

An object of the present invention is to provide a current transfer recording device that improves the drawbacks of the above-described current transfer recording device.

In other words, first 1. The supplied recording energy is efficient,
2. The recording method used for the recording itself. The specific goal is to realize a single current transfer recording device that has no crosstalk, can perform high-speed recording, can easily record 36-gradation images, and can easily produce gradation.

[Structure of the invention]

(Means for Solving the Problems) In order to realize the electrical transfer recording apparatus of the above-mentioned purpose, the present invention implements a method of improving the recording head. In other words, in the present invention, the shortest distance between each recording electrode and the common electrode is
The pitch of the recording electrodes in the main scanning direction is sufficiently smaller (1/
This is an electrical transfer recording apparatus that uses a recording head having a diameter of 2 or less, and an ink ribbon having at least a two-layer structure of a resistive layer and an ink layer.

(Function) By using such an electric transfer recording device, 1. Most of the supplied energy is lost because all the heat generated in the resistance layer between the recording electrode and the common electrode is used for recording. Things not to do, 2. 3. The current flowing out of the recording electrode flows into the common electrode without greatly spreading, so crosstalk does not occur and high-speed recording is possible.3. In other words, no matter what the recording pattern is, the resistance between each recording electrode and the common electrode is almost constant. Since the width of the recorded pixel in the sub-scanning direction is shorter than the width in the main-scanning direction, each B electrode can be recorded while moving the recording head in the sub-scanning direction. By changing the time that the current is applied, it is possible to adjust the length of the recorded pixel in the sub-scanning direction, and it is also easy to perform gradation recording using ink suitable for binary recording. It has characteristics.

(Example) 0 First Example Hereinafter, one example of the current transfer recording apparatus of the present invention will be described with reference to the drawings.

FIG. 1 shows a serial printer as an electrical transfer recording apparatus according to an embodiment of the present invention. In the figure, a recording head 11 has, for example, 40 recording electrodes (not shown) arranged in a vertical line at a density of 10 recording electrodes/1 m, and is supported by a pair of head holders 12 and 13. A recording head assembly 10 consisting of a recording head 11 and head holders 12 and 13 includes a recording head urging means (
(not shown) is pressed against the platen 14 during recording,
When not recording, the pressure contact state is released. The pressing force of the recording head 11 against the platen 14 needs to be appropriately strong because if it is too strong, the transferred characters may flow or the non-recording portions of the recording paper 27 may be smeared. The guide roller (15) is a roller that determines the angle at which the ink ribbon (16) approaches the recording head. ink ribbon(
No. 16) has a two-layer structure in which a heat-melting ink layer (not shown) with a thickness of about 61 mm is provided on a resistive layer of about 16 mm thick made of polycarbonate with conductive carbon dispersed therein. This ink ribbon 16 is housed in a ribbon cassette 20. A pair of pinch rollers 21 and 22 constitute an ink ribbon conveying means. Recording head assembly 10.
Guide roller 15. The ink ribbon transport means 21 , 22 and the ink ribbon cassette 20 are mounted on a carriage 23 . The carriage 23 is guided by a guide bar 24, and the rotation of the carriage drive motor 25 is transmitted via a timing belt 26, so that the platen 1
Move left and right along 4. The platen 14 is rotated by the rotation of the platen driving motor 28 being transmitted via the timing belt 29 . The recording paper 27 is, for example, PPC paper with a smoothness of about 20 seconds, is wound around the platen 14, and is transported by the rotation of the platen 14.

Next, the operation of this embodiment will be explained. In the initial state, the carriage 23 is at a home position at the left end of the guide bar 24 in the figure, and moves to the recording start position in response to a recording start signal. During this time, the recording head 11 is pressed against the platen 14 by the recording head urging means, and the recording electrode, ink ribbon 16 . The recording paper 27 and the platen 14 are in close contact with each other to form a recording area. The carriage 23 moves to the right in the figure at a speed of about 6 inches/sec while printing and recording in accordance with the recording start signal. At this time, ink ribbon 1
6 is driven by pinch rollers 21 and 22, and is wound to the left in the figure at the same speed as the moving speed of the carriage 23 or at a slower speed.

The recording head (13) used for this recording will be explained using FIG. 2. FIG. 2(a) is a diagram showing the positional relationship between the recording electrodes (0 and common electrode 2) of the recording head (13).

In the case of this embodiment, since the resolution is 10 lines/+m, the pitch P of the recording electrodes 0 in the main scanning direction is approximately 100-. The recording head (13) of the present invention is characterized by recording electrodes
The feature is that the distance Q between the electrode and the common electrode ■ is less than 1/2 of P. In embodiments of the invention, this distance Ω
FIG. 2(b) is a diagram showing the actual structure of the recording head (13) used in the example. The common electrode (2) is made of conductive metal. For example, in this embodiment, aluminum is used.

Also, since this part not only serves as a common electrode but also supports the mechanical strength of the recording head, it needs to be made thick to some extent, and in the case of this example, the thickness is approximately 5.
++n aluminum block is used. The recording electrode (3) is formed on a thin insulating layer (30), and in this embodiment is composed of a tungsten electrode with a thickness of approximately 25 mm. The insulating layer (30) was made of a heat-resistant polyimide resin having a thickness of approximately 20 mm. This insulation M5
The thickness of (30) will set the distance Q between the recording @pole and the common electrode. To manufacture such a recording head, first, an insulating layer (30) is pasted on a conductive metal that will become a common electrode, and then a metal that will become a recording electrode (2) is pasted on top of that. Then, to form recording electrode 0,
By performing etching, a recording head as shown in the figure can be manufactured. The width of the electrode formed by this etching is approximately 50-9 in this embodiment, and the distance between one recording electrode and the adjacent recording electrode is approximately 501. Thereafter, the tip is polished to form a recording head as shown in the figure.

When such a recording head is used, it has the following advantages. Because the distance between recording electrode 0 and common electrode ■ is sufficiently smaller than the recording electrode pitch, the current flowing from the recording electrode does not spread much in the main scanning direction.
flows into the common electrode.

For this purpose, as shown in Figure 3, if a two-layer ink ribbon consisting of a resistive layer (2) and an ink layer is used, a current flows through the resistive layer between the recording electrode (0) and the common electrode (0), and during this period The entire resistance layer generates heat.This eliminates the loss that occurs in conventional current transfer recording devices.In addition, the current hardly spreads in the main scanning direction, making it difficult to print any type of recording pattern. In any case, the currents flowing from one recording electrode can always flow into the common electrode without affecting each other.In other words, it has the feature that no crosstalk occurs.For this reason, Regardless of the recording pattern, all electrodes can be driven simultaneously, allowing high-speed recording.

Furthermore, the fact that the currents flowing out from each recording electrode do not affect each other means that the resistance when looking at the common electrode from each recording electrode is always kept almost constant regardless of the recording pattern. In conventional electrical transfer recording devices, this resistance changes depending on the recording pattern, so
Each recording electrode is driven by a constant current circuit. Since constant current circuits have large losses, it is difficult to integrate them into ICs. In contrast, in the current transfer recording apparatus of the present invention, since the resistance between the recording electrode and the common electrode is approximately constant, it is possible to drive each electrode at a constant voltage. When constant voltage drive becomes possible,
It is possible to use the thermal head driver IC, etc., which was conventionally used in the drive circuit of the thermal head, as is.
Therefore, it becomes possible to realize an electrical transfer recording device at low cost.

Furthermore, in an electric transfer recording device using such a recording head, the distance between the recording electrode and the common electrode is sufficiently smaller than the pitch of the recording electrodes in the main scanning direction, so the formed image dots are formed in the sub-scanning direction. width is shorter. Therefore, by scanning the recording head almost continuously in the sub-scanning direction while controlling the pulse width of the energizing pulse, it is possible to control the length of the pixel in the sub-scanning direction. In other words, images with density gradations can be handled by controlling the length of the pixel in the sub-scanning direction. Of course, controlling the energizing pulse width in order to control the length of the image dot means controlling the energy generated in the resistive layer, so it is natural that the image dot density will change. By controlling the length of the dots, even more fine-grained density control can be achieved. In particular, it has the feature of realizing high-speed gradation image recording using heat-melting ink suitable for binary recording.

Although one embodiment of the present invention has been described above, it is not limited to the embodiment described here. In the embodiment shown here, an ink ribbon with a two-layer structure was shown as an example, but the conventional embodiment It is also possible to use an ink ribbon with a three-layer structure as shown in the example.

In particular, when the thickness of the resistive layer is greater than the distance between the recording electrode and the common electrode, current flows only near the surface of the resistive layer, and heat generation is greatest near the surface. In such cases, using a three-layer ink ribbon allows the current to flow inside the resistive layer, bringing the heat generating point closer to the ink. For this reason, high-speed recording can be achieved.

Further, the material of which the recording head is made is not limited to that of this embodiment. For example, although insulating resin was used as the material for the insulating layer, there is also a method of using insulating ceramics such as alumina. All current transfer recording apparatuses, which are the gist of the present invention, in which the distance between the recording electrode and the common electrode are 1/2 or less of the main scanning direction of the recording electrode, are included in the present invention.

0 Second Embodiment FIG. 4 shows a second embodiment of the present invention. This method produces a recording head for an electrical transfer recording device that is similar in shape to a conventional thermal head formed on a flat surface or a round bar. The difference from the conventional thermal head is that while the conventional thermal head had a heating resistor with a length almost equal to the recording electrode pitch between the recording electrode (e) and the common electrode (2), the present invention There is a gap less than 1/2 of the pitch of the recording electrodes.The resistance layer of the ink ribbon comes into contact with this part and plays the role of the heating resistor of the thermal head.Also, between the recording electrodes and the common electrode. (2) It is necessary to have higher abrasion resistance and abrasion resistance against discharge than the materials used in conventional thermal heads, at least in the vicinity of the gap.Therefore, in the recording head of this embodiment,
It is appropriate to use tungsten or the like. The manufacturing method involves pasting tungsten on an alumina or glass substrate, etching it to form electrodes, and then pasting insulating resin (the shaded area in the figure).

In Fig. 4(a), the common electrode (2) is made uneven so that the distance is small only in the vicinity of the recording electrode (O).This has the effect of sufficiently suppressing the diffusion of current. As shown in FIG. 4(b), even if no unevenness is formed on the common electrode, current diffusion can be prevented by making the distance between the recording electrode (2) and the common electrode sufficiently small.

〔Effect of the invention〕

By using the present invention, it is possible to realize a current transfer recording device suitable for recording gradation images at high speed, at low cost, and with good recording energy efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the current transfer recording device of the present invention, FIG. 2 is a diagram for explaining a recording head used in the current transfer recording device of the present invention, and FIG. 3 is a perspective view of the current transfer recording device of the present invention. FIG. 2 is a diagram illustrating the recording principle of the apparatus. FIG. 4 is a diagram for explaining a second embodiment of the current transfer recording apparatus of the present invention. FIG. 5, FIG. 6, and FIG. 7 are diagrams for explaining a conventional electrical transfer recording apparatus. 1...Resistance M 2...Conductive layer 3...
·ink! 'J 4... Ink ribbon 5... Recording head 6... S electrode 7.
...Common electrode 8...Current 9...Recording medium agent Patent attorney Nori Chika Ken Yudo Mitsuyuki Matsuyama is the 1st cause 2nd country Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] Using an ink ribbon composed of at least a resistance layer and an ink layer that softens, melts, or sublimates when heated, recording is performed by bringing a plurality of recording electrodes and a common electrode into contact with the ink ribbon. In a current transfer recording device, an electric current is passed through a resistance layer of an ink ribbon between an electrode and a common electrode, and heat generated in the resistance layer transfers ink in the ink layer to a recording medium to form an image. An electrical transfer recording device characterized in that the distance between a recording electrode and a common electrode is 1/2 or less of the pitch between a plurality of adjacent recording electrodes.