JPH02136246A - Current supply recording head and current supply transfer recording apparatus - Google Patents

Abstract

PURPOSE:To enhance recording energy efficiency by eliminating the generation of a local high temp. point by prescribing the distance L between recording electrodes and a common electrode so as to satisfy T <= 2L < P in the relation between the arrangement pitch P of the recording electrodes and the thickness T of the resistor layer of an ink ribbon. CONSTITUTION:A large number of recording electrodes 6 arranged at a predetermined pitch P in one row and a common electrode 7 present at the position separated by a distance L from the recording electrodes 6 through an insulating layer 30 in almost parallel to the arrangement direction of said recording electrodes 6 are provided with respect to an ink ribbon 16 having a resistor layer 1 and the thermal ink layer 3 in contact therewith. At this time, the thickness of the resistor layer 1 of the ink ribbon 16 is set to T and the distance L between the recording electrodes 6 and the common electrode 7 is set so as satisfy T <= 2L < P.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) This invention relates to an energizing recording head that contacts an ink ribbon (recording sheet) that generates heat when energized and energizes the ink ribbon; The present invention relates to an electrical transfer recording device with excellent tone image recording characteristics.

(Prior Art) An electric transfer recording device softens, melts, or sublimates ink applied to an ink ribbon using heat, and transfers or diffuses 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 images. A typical thermal transfer recording device uses a thermal head to heat the ink ribbon from the base film side, whereas a current transfer recording device differs in that the ink ribbon itself generates heat to heat the ink.

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.
In addition, the print head does not generate heat, so there is no heat accumulation in the print head, and a large amount of print energy can be supplied without destroying the print head.The heat generating point on the ink ribbon is constantly moving, so direct current is possible. It has characteristics such as being For this reason, it is possible to record at higher speeds than ordinary thermal transfer recording devices, and it is possible to record on rough paper using rough paper ink with a high melting point.
High-speed recording of gradation images using sublimable ink becomes possible.

FIG. 6 is an explanatory diagram showing the recording principle of the current transfer recording apparatus. This current transfer recording device includes a resistive layer 1, a conductive layer 2,
An ink ribbon 4 composed of three layers, an ink layer 3, has a large number of recording electrodes 6 arranged on an energized recording head 5,
A common electrode 7 provided parallel to this is pressed from the resistance layer 1 side.

A recording current is selectively supplied to the recording electrodes 6 according to the image data supplied from the pattern generation circuit.

The recording current flows from recording electrode 6 to resistance layer 1 as shown by arrow 8.
- Conductive layer 2 - Resistance layer 1 - Common electrode 7 path. The Joule heat generated when this recording current flows through the resistance layer 1 heats the ink in the ink layer 3, and the ink is transferred to the recording medium 9 to form an image. Even when the recording current flows from the conductive layer 2 to the common electrode 7, the recording current flows through the resistive layer 1.
However, the contact area between the recording electrode 6 and the resistive layer 7 is sufficiently large compared to the contact area between the common electrode 7 and the resistive layer 1, and the distance between the recording electrode 6 and the common electrode 7 is 6
Since the pitch is sufficiently large compared to the pitch of , the heat generated when current flows from the conductive layer 2 to the common electrode 7 through the resistive layer 1 does not reach a level that would heat the ink in the ink layer 3 .

In such an electric transfer recording device, the width of the recording electrode 6 in the sub-scanning direction A (the direction of relative movement between the ink ribbon 4 and the recording head 5) is determined by By making the pitch of the recording electrodes 6 smaller than the pitch of the recording electrodes 6 in the array direction), it is possible to increase the resolution in the sub-scanning direction.

Figure 7 shows this situation. As shown in the figure, when the recording electrode 8, which has a width (W) that is sufficiently small compared to the pitch (P) of the recording electrode 6, is moved in the sub-scanning direction and the energization time is changed, the length in the sub-scanning direction increases. Different pixel points are formed. That is, by changing the current application time, the resolution in the sub-scanning direction can be arbitrarily changed 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 apparatus has such advantages, it also has some drawbacks. First of all, since the ink ribbon 5 has a multilayer structure, the cost is high. In particular, the fact that the conductive layer 2 is formed by vapor deposition of a metal such as A47 is a factor in the high 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, an electric transfer recording apparatus using an ink ribbon 4 consisting of only a resistive layer 1 and an ink layer 3 as shown in FIG. 8 has also been proposed. In this case, the recording current flows along the path of recording electrode 6 -> resistance layer 1 - common electrode 7, but since the current is concentrated only directly below recording electrode 6, an image is not formed near recording electrode 6. Ru.

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.
The energy consumed by the resistance of the resistive layer 1 and the energy consumed by the resistance of the resistive layer 1 when a current flows from the conductive layer 2 to the common electrode 7 become energy loss.

Furthermore, these losses become even larger as the number of recording electrodes that are simultaneously energized increases because the current that flows after the conductive layer increases. For example, in a printer with 40 recording electrodes arranged at a pitch of 10 dots/inch, when only one recording electrode is driven, more than 95% of the supplied energy is used for recording. If 40 recording electrodes are driven simultaneously, the loss increases to about 60%.

These drawbacks are the same in the conventional example shown in FIG. 8, which reduces the cost of the ink ribbon. In other words, all that is necessary for recording is heat generation near the recording electrode 6, but in reality the current 8 flows through the resistance layer 1 toward the common electrode 7, causing a large loss here. It is.

In order to solve the above problems, conventionally, the method shown in Fig. 9 (
The electrical transfer recording device shown in a) has also been proposed. By making the distance between the recording electrodes 6 and the common electrodes 7 approximately the same as the arrangement pitch of the recording electrodes 6, the entire resistance layer 1 between the recording electrodes 6 and the common electrodes 7 is heated, and one image is generated. This is a method of recording points, and almost no energy is lost, making it possible to realize an efficient electrical transfer recording device. However, this method has the disadvantage that it is difficult to drive all the recording electrodes simultaneously due to crosstalk between the recording electrodes, so although it is suitable for binary images, it is not suitable for recording gradation images.

First, the problem of crosstalk will be explained using FIG. 9(b). FIG. 9(b) is a diagram showing the relationship among the recording electrode 6, common electrode 7, resistance layer 1, and current 8 when FIG. 9(a) is viewed from the direction of arrow B.

Now, the odd numbered recording electrode 6-1.6 as shown in this figure.
-3.6-5 and the case where only the odd numbered electrodes are driven, the current 8 flowing from the recording electrode spreads as shown in the figure.
Even-numbered recording electrodes 6-2 that do not originally need to be recorded.
6-4. Current also flows through the part 6-6. As a result, if the heat accumulation phenomenon increases due to the increase in recording speed, image dots will also be formed in unnecessary areas. Further, even a slight mechanical factor such as uneven feeding of the recording head may cause these unnecessary pixels to be recorded, making the recording unstable. Sacrificing recording speed to eliminate these instabilities 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, which is suitable for recording a binary image. Furthermore, it is possible to record gradation images when using ink that can record dots with a density proportional to the amount of recording energy, such as heat-sublimable ink, but it is possible to record gradation images using This method has the disadvantage that it is not suitable for gradation recording using ink suitable for value recording.

(Problems to be Solved by the Invention) As mentioned above, the conventional electrical transfer recording device has high recording energy efficiency, high-speed recording without crosstalk, and gradation recording. It was difficult to meet.

This invention has high recording energy efficiency, can perform high-speed recording without causing crosstalk even when multiple recording electrodes are energized simultaneously, and uses an inexpensive ink ribbon using heat-melting ink. It is an object of the present invention to provide a current-carrying recording head and a current-carrying transfer recording device capable of performing gradation recording corresponding to pixels.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method for recording signals to be recorded on an ink ribbon that has at least a resistive layer and a heat-sensitive ink layer in contact therewith. In an energized recording head that energizes according to the current, a plurality of recording electrodes are arranged in a line at a predetermined pitch P, and a plurality of recording electrodes are arranged at a distance from the recording electrodes substantially parallel to the arrangement direction of the plurality of recording electrodes. When the thickness of the resistance layer is T, T≦
It is characterized by being formed to satisfy the condition 2L<P.

Further, the present invention improves the thermal sensitivity of the ink ribbon by bringing a current-carrying recording head into contact with an ink ribbon that generates heat when energized, and by energizing the ink ribbon by the current-carrying recording head to partially generate heat in the ink ribbon. In an electrical transfer recording device that transfers ink to a recording medium to form an image, the ink ribbon has a resistive layer and a heat-sensitive ink layer of at least a thickness T, and the electrical recording head is arranged in a line at a predetermined pitch P. The distance ML between a plurality of recording electrodes arranged in a direction parallel to the arrangement direction of these plurality of recording electrodes is T.
It is characterized by having a common electrode provided to satisfy the condition ≦2L<P.

(Function) In the current-carrying recording head according to the present invention, since the distance between the recording electrode and the common electrode is smaller than the pitch P of the recording electrode, that is, the pixel density, heat generation occurs in the resistive layer that contacts the picture electrode. Almost all of them are used for recording. In addition, since the distance between the recording electrode and the common electrode is at least twice the thickness T of the resistance layer of the ink ribbon, the recording current is not unevenly distributed only on the surface of the resistance layer, and is distributed in the thickness direction of the resistance layer. Since the recording current is also distributed, the generation of local hot points is eliminated, and the time for heat transfer to the ink layer adjacent to the resistive layer of the ink ribbon is shortened. Therefore, recording energy efficiency is improved.

Furthermore, in this invention, since the distance between the recording electrodes and the common electrode, IL, is smaller than the pitch P of the recording electrodes, the recording electrodes are driven simultaneously in order for the current flowing from the recording electrodes to flow into the common electrode without widening. However, almost no crosstalk occurs, and high-speed recording is possible. In other words, the resistance value between each recording electrode and the common electrode is almost constant for any recording pattern, so stable concentration can be achieved without constant current driving, which causes loss as described above. Pixel points are recorded.

Furthermore, for the same reason, the width of the recorded pixel in the sub-scanning direction is shorter than the width in the main-scanning direction, so the time for energizing each recording electrode is changed while moving the printhead in the sub-scanning direction. By doing so, it is possible to adjust the length of the recorded pixel in the sub-scanning direction, and gradation recording can be performed using an ink ribbon using a heat-melting ink suitable for binary recording.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a serial printer as an electrical transfer recording apparatus according to an embodiment of the present invention. In the figure, the recording head 11 has, for example, 40 electrodes (not shown) arranged in a vertical line at a density of 10 electrodes/m+i, and is supported by a pair of head holders 12 and 13. . Recording Rad 11 and Head Holder 12.13
The recording head assembly 10 is pressed against the platen 14 by a recording head biasing means (not shown) during recording, and is released from the pressed state during non-recording. 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.

The ink ribbon 16 has a two-layer structure in which a heat-melting ink layer (not shown) with a thickness of about 6 μm is provided on a resistive layer of about 18 μm thick made of polycarbonate with conductive carbon dispersed therein. This ink ribbon 16 is a ribbon cassette 20.
It is stored inside.

The pair of pinch rollers 21 and 22 constitute an ink ribbon conveying means. The recording head assembly 10, guide roller 15, ink ribbon transport means 21, 22, and ink ribbon cassette 20 are mounted on a carriage 23. The carriage 23 is guided by a guide bar 24 and moves left and right along the platen 14 by transmitting the rotation of a carriage drive motor 25 via a timing belt 26 . The platen 14 is rotated by the rotation of the platen drive motor 28 being transmitted via two timing belts.

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. The recording electrode, ink ribbon 16, recording paper 27 and platen 14 are in close contact with each other,
Form a recording site. The carriage 23 moves to the right in the figure at a speed of about 6 inches/second while performing stamp recording in accordance with a recording start signal. At this time, the ink ribbon 16 is driven by the pinch rollers 21 and 22 and is wound up to the left in the figure at the same speed as the moving speed of the carriage 23 or at a slower speed.

Next, the detailed configuration of the recording head 13 will be explained using FIG. 1. FIG. 1(a) shows the recording head 13 in FIG.
This figure schematically shows the structure around the recording section of . 1(b) and 1(e) show the positional relationship between the recording electrode 6 and the common electrode 7, and FIG. 1(e) shows a cross section taken along line AA' in FIG. 1(b). A common electrode 7 is provided substantially parallel to the arrangement direction of a plurality of recording electrodes 6 arranged in a line at a pitch P.

Here, in this invention, the distance ML between the recording electrode 6 and the common electrode 7 is determined by the arrangement pitch P of the recording electrode 6 and the resistance layer 1 of the ink ribbon 16 where the recording electrode 6 and the common electrode 7 contact.
It is defined by the relationship of thickness T, and is set to satisfy T≦2L<P. In this example, the resolution is IO books/lll1
1, the arrangement pitch P of the recording electrodes 6 is approximately 100μ.
It is m. Further, the thickness T of the resistance layer 1 is approximately 16 μm. Therefore, in the current-carrying recording head of this embodiment, the recording electrode 6
The distance between and the common electrode 77 is 18μm≦2L<100μ
m, that is, 8 μm≦L<50 μm, specifically, L−20 μm.

An example of the manufacturing process of the energized recording head 13 in this embodiment will be explained. First, a tungsten foil with a thickness of 25 μm was adhered to a polyimide film 30 with a thickness of about 20 μm, a resist coating was applied thereon, and a mask for a recording electrode pattern was formed by regular gluing lithography.

Next, unnecessary tungsten was removed by etching treatment to form recording electrodes 6. The electrode width is 50 μm, and the space between each electrode is approximately 50 μm. At the end of the tungsten conductor opposite the electrode that contacts the resistance layer of the ink ribbon, there is an external terminal (not shown) for connection to an external circuit.
was formed. This electrode sheet was adhered to an aluminum plate having a thickness of approximately 51 mm, which would serve as the common electrode 7, and the end surface in contact with the resistance layer of the ink ribbon was processed as shown in FIG. 1(C) to obtain a recording head. Here, the polyimide film 30 is insulating, and the processed cross-sectional thickness of the film 30 is equal to that of the recording electrode 6.
and the distance from the common electrode 7.

The current-carrying recording head according to the present invention configured as described above has the following excellent advantages.

First, the distance between the recording electrode 6 and the common electrode 7 is
Since the arrangement pitch P is sufficiently smaller than the arrangement pitch P of (1), the current flowing from the recording electrodes does not spread much in the direction of the recording electrode array and flows into the common electrode.

On the other hand, inside the resistance layer 1 of the ink ribbon 16, which is the heat source, the distance between the recording electrode 6 and the common electrode 7 is more than twice the thickness T of the resistance layer 1, so the distance shown in FIG. As shown in FIG. 1, the recording current (indicated by the arrow) spreads in the thickness direction of the resistive layer 1 between the recording electrode 6 and the common electrode 7, and the entire resistive layer between them generates heat.

On the other hand, as shown in FIG. 3(b), when the distance ML' between the recording electrode 6 and the common electrode 7 becomes less than twice the thickness T of the resistive layer 1, the recording current (indicated by the arrow) decreases. Path between both electrodes +#
As L' becomes shorter, it concentrates near the surface of the resistance layer 1, resulting in an excessively high temperature locally compared to the case of FIG. Because the heat source is located far away, the heat transfer efficiency deteriorates.

In the energization transfer apparatus using the energization recording head of the above-described embodiment, the loss unlike the conventional energization transfer recording apparatus explained in FIG. 3(b) is eliminated. Furthermore, the recording current hardly spreads in the main scanning direction, and no matter what the recording pattern is, the current flowing from one recording electrode 6 always flows into the common electrode 7 without flowing into other recording electrodes. , no crosstalk occurs. Therefore, all electrodes can be driven simultaneously for any recording pattern, and high-speed recording is possible.

Further, since the currents flowing from each recording electrode 6 do not influence each other, the resistance value when looking at the common electrode 7 from each recording electrode 6 is always kept almost constant regardless of the recording pattern. In a conventional current transfer recording device, each recording electrode is driven by a constant current circuit because this resistance value changes depending on the recording pattern. However, constant current circuits are not suitable for IC implementation because they generate a large amount of heat due to drive transistors, current limiting resistors, and the like. In contrast, in the current transfer recording apparatus of the present invention, since the resistance between the recording electrode 6 and the common electrode 7 is approximately constant, it is possible to drive each electrode at a constant voltage. Therefore, the constant voltage drive type thermal head driver IC used in the thermal head drive circuit of conventional thermal transfer recording devices can be used as is, and it is possible to realize a current transfer recording device at low cost. Become.

Furthermore, in the current transfer recording device using the above-described current-carrying recording head, since the distance ML between the recording electrodes 6 and the common electrode 7 is sufficiently smaller than the arrangement pitch P of the recording electrodes 6, the formed image point is shorter in the sub-scanning direction (direction perpendicular to the arrangement direction of the recording electrodes 6) than in the main scanning direction (the arrangement direction of the recording electrodes 6). Therefore, by scanning the energized 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 to control the length of the pixel means controlling the energy generated in the resistive layer 1, so it is natural that the pixel density will change. By controlling the length of the dots, even more fine-grained density control can be achieved. As a result, high-speed gradation image recording can be realized using an inexpensive heat-melting ink suitable for binary recording.

The structure of the current-carrying recording head in this invention includes the fourth
As shown in the figure, a structure in which a recording electrode 6, a common electrode 7, and an insulating layer 30 are provided on one plane of an insulating substrate 31 made of alumina or the like can also be used. In this case, the recording electrode 6 and the common electrode 7
As a method for forming the electrode, a thin film sputtering or vapor deposition process, a thick film printing/baking process, a plating method, etc. can be used.

Further, it is desirable that the insulating layer 30 and the picture electrodes 6 and 7 are substantially flush with each other.

In addition to the two-layer structure ribbon used in the above embodiment, the ink ribbon used in this invention has a resistance layer 33 on one side of an insulating base film 32 and an ink layer 34 on the other side as shown in FIG. An ink ribbon with a three-layer structure can also be used. For the insulating base film 32, polyimide 5 aramid resin, polyester, or the like having good heat resistance can be used.

The resistance layer 33 is formed by solvent coating or hot melt coating on the insulating base film 32 a thermoplastic resin in which conductive particles are dispersed. In this invention, the heat that causes the heat-sensitive ink layer to generate heat is generated throughout the resistance layer between the recording electrode and the common electrode, so the maximum temperature can be lower than conventional ones, and a thermoplastic resin with a relatively low softening point is also used. It becomes possible.

[Effects of the Invention] According to the present invention, it is possible to realize high-speed recording with high recording energy efficiency, and it is also possible to modulate the area within one pixel in the sub-scanning direction. The ink ribbon enables gradation recording by modulating the density of each pixel. Furthermore, as a secondary effect, the heating area can be sharpened, so recording with good image quality can be obtained.Also, since the entire resistance layer between the recording electrode and the common electrode generates heat, the maximum temperature can be reduced. By keeping it low, it is possible to reduce mechanical strength deterioration of the ink ribbon and to reduce recording defects due to melted adhesion of resistive material to the current-carrying recording head.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the configuration of an energized recording head according to an embodiment of the present invention, FIG. 2 is a perspective view showing the configuration of an energized transfer recording apparatus according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view showing the structure of the main part of the energized recording head according to another embodiment of the present invention, and FIG. 5 is a diagram for explaining the effects of the energized recording head of the present invention. 6, 7, 8, and 9 are cross-sectional views showing other examples of ink ribbons that can be used in transfer recording devices, and are diagrams for explaining conventional electrical transfer recording devices and their problems. It is. DESCRIPTION OF SYMBOLS 1... Resistance layer, 2... Conductive layer, 3... Ink layer,
4... Ink ribbon, 5... Current recording head, 6...
...Recording electrode, 7...Common electrode, 30...Insulating layer.

Claims (2)

[Claims] (1) In an energizing recording head that energizes an ink ribbon having at least a resistive layer and a heat-sensitive ink layer in contact therewith in accordance with a signal to be recorded, a plurality of ink ribbons arranged in a line at a predetermined pitch P are used. A recording electrode, and a common electrode provided at a distance L from the recording electrode substantially parallel to the arrangement direction of the plurality of recording electrodes, where T is the thickness of the resistive layer, T≦2L. A current-carrying recording head characterized in that the recording electrode and the common electrode are formed so as to satisfy the condition <P. (2) A current-carrying recording head is brought into contact with an ink ribbon that generates heat when energized, and the current-carrying recording head energizes the ink ribbon to partially generate heat in the ink ribbon. In an electrical transfer recording device that forms an image by transferring the image to a recording medium, the ink ribbon has a resistive layer and a heat-sensitive ink layer having at least a thickness T, and the electrical recording head is arranged in a line at a predetermined pitch P. A common electrode is provided parallel to the arrangement direction of the plurality of recording electrodes so that the distance L from the recording electrodes satisfies the condition T≦2L<P. Characteristic electrical transfer recording device.