JPH02233263A - Recording head and thermal recording device using the recording head - Google Patents

Abstract

PURPOSE:To perform a multilevel recording and to easily realize a recording in multigradations by incorporating at least one narrow part in a heat generating resistor and forming the narrow part of a conductor or a conductor part formed on the resistor. CONSTITUTION:Since a heat generating element is split and the split elements are connected by a narrower conductor part 18 that the element in a thermal head, the density of a current 20 flowing in the element 11 is increased in the narrow part 18 and the vicinity 11H of a connecting point of the split elements 11a, 11b. The temperature near the part 18 is particularly high of the elements 11. When a pulse signal applying time is gradually increased, a lateral temperature in the section Z-Z' of the element 11 is varied along a curve 42 53 44, and transfer areas 42A-44A are altered. The temperature slope of the vicinity of the electrode is sufficiently large, and pixel density can be accurately altered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording head capable of expressing halftones and a thermal recording apparatus using the recording head.

[Prior Art] Recording devices such as printers and facsimiles use multiple dot forming elements provided in a recording head to record information (image signals).
It forms a dot pattern on a recording sheet (a recording medium such as a recording paper or a thin plastic plate) by selectively driving the dots based on the following information. The formats of such recording devices include the serial type, which prints while moving the recording head in the width direction of the sheet, the line print 1 type, which records a predetermined length in the row direction, and the one-page batch type. There are paper print types that record data.

In addition, recording methods include thermal, inkjet, and wire dot methods. Among these, the thermal method is
It can be divided into a thermal transfer method, which uses an ink sheet to transfer ink to plain paper, and a thermal method, which uses a thermal head to heat the thermal paper to develop color.

2. Description of the Related Art Conventionally, a halftone recording method has been employed to express density differences during color recording or image recording using multiple colors such as cyan, magenta, yellow, and black. In such conventional halftone recording, a method based on the principle of binary recording is generally adopted, and in order to express gradation using the conventional method, multiple dots are treated as one unit, and the dots in that unit are Techniques have been used to express halftones in a pseudo manner using an area gradation method such as a dither method, which expresses halftones by the ratio of on/off (binary values).

[Problem to be solved by the invention] However, when the above-mentioned area gradation method is adopted, the number of dots required for one pixel increases in order to express many gradations, resulting in a decrease in image resolution. There is a problem with doing so. In order to obtain, for example, an image with 64 gradations and a resolution of about 6 pixels/mm by this area gradation method, the resolution of the recording head needs to be about 48 dots/mm. To achieve this with a thermal printer, 4
An 8 dot/mm thermal head is required, but
It is extremely difficult to manufacture such a high-density thermal head, and even if it were possible to manufacture it, the number of elements would be enormous, which would require a large-scale drive circuit to drive the thermal head, making it impractical. In other words, there is a limit to the ability to obtain high-quality gradation recording with binary recording, and there has been a need to put into practical use multi-value gradation recording that expresses the size of one dot in multiple gradations by some method. .

Conventionally, in recording by thermal melt transfer using a commonly used thermal head, density changes corresponding to changes in printing energy are as shown in FIG. 14(A). That is, the rate of change in recording density with respect to applied energy is large;
In addition, the variation in recording density was large as shown by the length of the vertical line in the graph, so it was very difficult to achieve an intermediate density. In the conventional thermal head shown in FIG. 14(B), since the heating element 101 and the electrode 102 are shaped to have the same width, the heating element 1. The distribution of the current flowing through 01 becomes almost uniform.

Note that 103 indicates the direction in which the current flows.

For this reason, the temperature distribution of the heating element 101 is such that the central portion of the heating element 101, where the amount of heat dissipated is relatively small, has a slightly higher temperature. Therefore, by changing the application time of the pulse voltage applied to the electrode 102, the temperature distribution of the heating element 101 is changed as shown in FIG. Even so, whether the temperature of the heating element 101 is higher than the melting point T of the thermal transfer ink or not depends on its position. Therefore, even if the same applied energy is applied to the heating element 101 as shown in FIG. 14(A),
This slight difference in the position of the heating element causes a large difference in recording density.

For this reason, the applicant of the present invention proposed a thermal head capable of multilevel recording in Japanese Patent Laid-Open No. 6-54261. According to this, by making the width of the electrode at the connection point between the electrode and the heating element less than or equal to the recording effective width of the heating element, the part of the heating element near the connection point with the electrode can generate more heat in one heating element. By doing so, it is possible to provide a heat generation distribution.

However, even with this configuration, there is a risk that sufficient gradation may not be obtained when recording on recording paper with an uneven recording surface, and it is desirable to develop a thermal head that can record with even better gradation. It was rare.

The present invention has been made in view of the above-mentioned conventional examples, and an object of the present invention is to provide an inexpensive recording head capable of multi-level recording and easily realizing multi-gradation recording, and a thermal recording device using the recording head. With the goal.

[Means for Solving the Problems] In order to achieve the above object, the recording head of the present invention has the following configuration. That is, it includes a plurality of heating resistors arranged in a row and an electrode for supplying electrical energy to each of the plurality of heating resistors, and the width of the heating resistor is narrower than the width of the heating resistor. It includes at least one narrow portion, and the narrow portion is formed by a conductor or a conductor portion provided on the heating resistor.

Further, a thermal recording apparatus using the recording head of the present invention that achieves the above object has the following configuration. That is, it includes a plurality of heating resistors arranged in a row and an electrode for supplying electrical energy to each of the plurality of heating resistors, and the width of the heating resistor is narrower than the width of the heating resistor. A recording head I, which includes at least one narrow portion, and the narrow portion is formed by a conductor or a conductor portion provided on the heat-generating resistor, and a multivalued image signal are manually inputted, and the recording head I. gradation determining means for determining the gradation of image data to be recorded by each heating element of the recording head in accordance with the gradation; and recording means for recording by energizing each heating element of the recording head according to the gradation. has.

[Function] With the above configuration, in this recording head, each of the plurality of heating resistors includes at least one narrow portion narrower than the width of the heating resistor, and the narrow portion is provided on the conductor or the heating resistor. By forming the electric conductor part, the density of the current flowing through the heat generating resistor is changed, and the heat distribution is biased, thereby making it possible to express gradations.

According to another recording head, a conductor portion is provided in the heat generating resistor so that the heat distribution can be changed by changing the density of the current flowing through the heat generating resistor.

According to a thermal recording device of another invention, a recording head capable of gradation expression is used, a multivalued image signal is input, and each heating element of the recording head records data in accordance with the gradation level of the image signal. Determine the gradation level of the image data. Then, according to the gradation level, each heating element of the recording head is energized to perform recording.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Note that the embodiments described below will be explained using a thermal recording method using a thermal head as an example, but the present invention is not limited thereto; for example, an image may be recorded by ejecting an ink liquid using heat. The present invention can also be applied to a recording method that records an image using heat, such as an inkjet recording method.

[Description of the thermal head (Figs. 1 to 4)] Fig. 1 is a diagram showing the shape of the heating element and electrodes of the thermal head of the embodiment, and Fig. 1 (A) shows one heating element and its electrode. A top view of the
FIG.

The heating element 11 and electrode portion 12 of this thermal head will be explained.

In the thermal head of this embodiment, as shown in FIG. 1(C), a glaze layer 14 as a heat storage portion is formed on an alumina substrate 13. Furthermore, a film of the resistance layer 15 is formed thereon by vacuum evaporation, sputtering, or the like.

Then, the center portion (conductor layer 19 portion) of the resistance layer l 2 15 is cut by photolithography, photoetching, or the like.

Then, the electrode layer 16 is formed thereon by the above-mentioned vacuum evaporation, sputtering, etc., and the electrode layer 16 and the central conductor layer 19 are formed in the same process by photolithography, photoetching, etc. as shown in the figure. The heating element 11 and the electrode part 12 are formed by this process, and a wear-resistant layer 17 is further formed thereon by sputtering or the like. Here, heating element 11
The portion called “ ” is the portion of the resistance layer where the electrode layer 16 is cut.

As is clear from FIG. 1(A), the thermal head of this embodiment has a configuration in which the heating element of the conventional thermal head is divided into two parts and these parts are connected by a conductor part l8 having a width narrower than that of the heating element. , the heating element 11 within one pixel is divided into two heating elements 11a and 1lb. Furthermore, as is clear from FIGS. 1B and 1C, the glaze layer 14 at the center within one pixel protrudes from the surroundings, so this portion of the thermal head has a convex shape. Here, 1
2a is a common electrode, and 12b is an individual electrode.

[Description of Thermal Transfer Recording Section (FIG. 3)] FIG. 2 is a schematic diagram of the recording section of the thermal transfer recording apparatus using the thermal head of FIG. 1.

The thermal head 31, which includes a plurality of heating elements 11 and electrodes 12 for supplying electric energy to the heating elements 11, is arranged facing the platen 34, and is attached so as to be able to press against and separate from the platen surface. During recording, the heat generating part of the thermal head 31 is connected to a recording sheet 33 supported by a platen 34, that is, an ink sheet 3 having an image-receiving layer.
2 and are pressed together. In this state, by selectively driving the heating element 11 of the thermal head 31 based on the image signal, ink is melted and transferred onto the recording sheet 33 to perform recording.

The heating element 11 is driven by applying a pulse voltage to the electrode 12 thereof. Then, each time a predetermined recording is completed, the recording sheet 33 and the ink sheet 32 are
It is transported in the direction of the arrow in FIG.

[Description of the first embodiment (Figs. 3 and 4) Fig. 3 (
A) is a diagram showing the flow of current flowing from the common electrode 12a toward the individual electrodes 12b when a pulse voltage is applied to the heating element 11 of the thermal head shown in FIG. 1 through the electrode 12.

In FIG. 3(A), 20 represents the current flowing through the heating element, and the density of the current flowing through the heating element 11 is near the connection point between the narrow conductor portion 18 and each of the heating elements 11a and llb. It is getting bigger at 11H.

FIG. 3(B) shows the vicinity of the conductor part 18 (third part) in the heating element 11.
It is a figure which shows the temperature distribution in the zz' cross section of figure (A).

The temperature near this conductor portion 18 is particularly high among the heating elements 11, and the temperature difference with other parts of the heating elements 11 is extremely large. Then, in order to change the applied energy, when the application time of the pulse signal applied to the heating element 11 is gradually lengthened, the z of the heating element 11 is
The temperature distribution in the width direction in the -z' cross section is shown in Figure 3 (B).
The curve changes as shown in the middle curve 42→43-44.

Here, does the glaze layer 14 of the thermal head protrude from the surroundings around the center of one pixel? Therefore, the pressing force applied to the recording sheet is concentrated near the connection point between the conductor portion 18 and the heating element 11. Also,
Since the glaze layer 14 is thicker in this area, the amount of heat stored in that area increases, and the effect of concentrating heat energy becomes more pronounced. This makes it easier for the ink of the ink sheet to be transferred in the vicinity of this connection point.

In FIG. 3(B), T■ indicates the melting point of the ink on the ink sheet, and in a temperature range higher than this, the ink on the ink sheet will be melted and transferred to the recording sheet.

Therefore, the area of the transferred dots changes as shown in FIG.
) of 42A. 43A. It spreads as shown by 44A. At this time, since the shape of the head near the connection point between the conductor portion 18 and the heat generating element 11 is convex, the dot area is small and image reproducibility is improved in areas with low recording density. Furthermore, for example, the applied energy may be changed as shown in FIG. 3(B). When the temperature of the thermal head is changed, the transfer area changes as shown in FIG. 3(C), but at intermediate energy, the transfer area becomes even more intermediate, making continuous gradation possible.

That is, one heating element 11 can record multi-value information.

Moreover, as shown in FIG. 3(B), the heating element 1 of the example
The temperature gradient near the electrode 1 is sufficiently large compared to the conventional heating element shown in FIG. 14, and the temperature of the heating element 11 is equal to the ink melting temperature T. It is a sufficiently larger value than .

Therefore, it is possible to suppress changes in the recording density due to minute changes in the printing energy, and the fluctuations in the recording density with respect to the printing energy have a slope (rate of change) as shown in the graph shown in Figure 4. The variation in recording density with respect to processing energy is shown by the length of the vertical line in the graph, and is sufficiently smaller than in the case shown in FIG. 14(A).

For this reason, for example, by controlling the time or voltage value of applying a pulse signal to the thermal head, that is, the applied processing energy, it is possible to accurately change the pixel density recorded by one heating element. It becomes possible to express the following, and the variation in density caused by halftone recording becomes sufficiently small and stable.

In addition, the heating center part is the heating element (heating element 11a and llb
Since it is located at the center of the dots 1 and 2 (assuming that they are integral), the amount of heat radiated to the common electrode 12a and the individual electrodes 12b is reduced, and mutual interference with adjacent dots 1. is reduced. On the other hand, the conductor part 18 located near the heat generating part is a heat dissipating material that absorbs heat from the heat generating part and reduces the thermal efficiency of the heat generating element 11, but since its capacity (area) is extremely small, it may cause deterioration of energy efficiency due to heat dissipation. No problems at all.

Rather, since the heat from the heating center is taken away appropriately, there is an effect that the temperature of the heating resistor does not locally become too high. That is, the thermal head of this embodiment has excellent resolution, can effectively use heat generation energy, and furthermore, by providing heat generation distribution, multi-level recording is possible.

In this embodiment, the resistive layer 15 is not provided under the narrow conductor section 18, but in order to simplify the manufacturing method of the head, a resistive layer is provided under the conductor section 18. A similar effect was observed even when left alone. Further, the conductor portion 18 may be formed of a material having approximately the same conductivity as the material of the electrode layer 16 forming the electrode portion 12, and does not necessarily need to be made of the same material.

Further, in this embodiment, the heating element section is divided into two parts, but it may be divided into even more parts. In this case, it goes without saying that the number of conductor parts connecting these heating elements is increased.

[Head Structure of Second Embodiment (FIGS. 5 and 6) FIG. 5 is a top view of the heating element and electrodes of the thermal head of the second embodiment. Compared to the thermal head of the first embodiment, this thermal head has two narrow conductor parts instead of one, and common parts with those in Fig. 1 are indicated by the same symbols. .

In the thermal head shown in Fig. 5, two heating elements 1
1a, 1]. b are connected by two conductor portions 18a, 18b which are provided on both sides of these heating elements 11a, 1lb, or are provided at a distance.

Then, the heating elements 1la, llb and the two conductor parts 18a
, 18b are 2 points each (53.54 and 55, 5
6), current concentrates near these connection points, and the current density in the vicinity increases.

As a result, by changing the thermal energy applied to the thermal head based on the same principle as in the embodiment described above, the dot area of the ink to be transferred can be adjusted as shown in FIG. 6 (A).
Changes can be made as shown in the shaded areas in (B) and (C). In FIG. 6, parts common to those in FIG. 5 are indicated by the same symbols, and the applied energy is A<B<C. In this way, halftone expression can be achieved by changing the dot area in accordance with the printing energy.

In this way, according to the second embodiment, in addition to the individual electrodes and the common electrode, a conductor portion having a width narrower than that of the heating element is formed, and this conductor portion electrically connects the heating elements on the individual electrode side and the common electrode side. is connected to. Then, by controlling the pulse width of the driving pulse applied by the heating element, it is possible to change the amount of ink transferred to the recording sheet to express halftones. Note that the number of conductor parts is not limited to two.

[Description of the third embodiment (Figs. 7 and 8)] Fig. 7 (
A) is a diagram showing an example of the structure of a heating element and electrodes of a thermal head according to a third embodiment, and parts common to those in FIG. 1 are designated by the same numbers.

Here, the heating element 11c of the thermal head is not divided, and the conductor 21 is provided in the center of the heating element 11c.

FIG. 7(B) is a diagram showing the flow of current in the thermal head of FIG. 7(A).

Here, as shown in 22, the current concentrates on the conductor 21 in the middle of the heating element 11c, which has a small resistance value, so the current density near the central conductor 21 becomes high, and Fever occurs intensively. Therefore, by changing the energy applied to the thermal head, as shown in Figure 8 (
Since the transfer area of the ink sheet changes as shown by the shaded areas in A), (B), and (C), multi-gradation recording becomes possible. As described above, the thermal head of the third embodiment has the effect that ink transfer at both ends of the center is performed more easily than in the first embodiment.

Note that, of course, the position and number of the conductor portions 21 are not limited to this embodiment.

[Description of the thermal transfer recording device (FIGS. 11 to 13)] FIG. 9 is a block diagram showing a schematic configuration of the thermal transfer recording device using the thermal head 31 of the embodiment, and parts common to FIG. 2 are designated by the same numbers. It is shown in

In FIG. 9, 110 is a plain paper cassette that holds plain paper as recording sheets, 111 is a sensor that detects the presence or absence of plain paper, and 106 is a cassette for holding plain paper.
This is a transport motor for transporting by jumping up from 0. A stepping motor 123 rotates the platen 34 via a speed reduction mechanism (not shown). 131 is a motor for raising/lowering the thermal head 31, and the thermal head 3 is driven by this motor 131.
1 is transferred to the platen 3 via the ink sheet 32 and the recording paper.
4 (down state) or separated from the platen 34 (up state). Further, reference numeral 139 is a motor that is a driving source for the feeding mechanism of the ink sheet 32;
The rotation of the ink sheet 39 is transmitted to the drive shaft of the take-up roll l40, and the ink sheet 32 is taken up in the direction of the arrow. Also, 14
1 is a supply roll for the ink sheet 32;

Reference numeral 35 denotes a buffer memory for temporarily holding manually-generated image data, and reference numeral 36 denotes an image data conversion table for converting the image data read out from the buffer memory 35, which is usually composed of a look-up table in a ROM or the like. 37
is a head drive pulse control circuit whose details are shown in FIG. 1o.

FIG. 11 is a block diagram showing the configuration of the thermal head 31.

In the figure, reference numeral 11 denotes a heating element, and each heating element is created based on the above-described embodiment, and is provided for one line in the width direction of the recording paper. 233 is a latch circuit that latches one line of recording data, and 234 is a shift register, which manually inputs serial recording data (gradation data) 444 in sequence in synchronization with a clock signal CLK. The serial data thus input to the shift register 234 is transmitted to the latch signal 2
35, the data is latched by the latch circuit 233 and converted into parallel data. In this way, the recording data corresponding to each heating element is held in the latch circuit 233. and,
The timing and time for applying voltage are determined by the strobe signal STB445, and the AND circuit 2 with data
The output transistor 231 connected to the terminal 32 is turned on. As a result, the corresponding heating element l1 is energized, and the heating element is driven to generate heat. Note that 12a is a common electrode, and 12b is an individual electrode.

Next, referring to FIG. 10, head drive pulse control circuit 3
7 will be explained.

450 is an oscillator that outputs a clock signal CLK of a predetermined frequency, and 451 is a frequency divider that divides the clock signal CLK and outputs a latch signal 235 every time the number of heating elements in one line of the thermal head 31 is counted, for example. It is a circuit. 4
40 corresponds to each pixel of input pixel data, and CL outputs tone data 444 to each register stage of the shift register 234.
This is a gradation conversion decoder that transfers data in synchronization with the K signal. With this, for example, when processing a color image, YM,
A gradation conversion decoder 440 performs gradation conversion for each C color.

Reference numeral 441 denotes a gradation counter, which counts up each time the latch signal 235 is input, and counts up based on the instruction signal of the CPU 42.
bits), mod if it is a fusible ink sheet.
16 (4 bits) counting is being performed. The gradation conversion decoder 440 compares the counted value from the gradation counter 441 with each input pixel data, and if the pixel data is greater or equal, the gradation data 444 is set as "1".
”, and when the pixel data is smaller, it outputs ゛O゜゜.The strobe signal generation circuit 442 outputs the strobe signal STB4 a little later than the latch signal 235.
45, which drives the heating element and performs recording.

FIG. 12 is a diagram showing the driving of the thermal head 31 and the timing of the strobe signal STB in the embodiment.

The thermal head 31 is a line type head, and 70 indicates the recording timing for one line.

Now, assuming that the image data per pixel input to the gradation conversion decoder 440 is composed of, for example, 6 bits, there can be 64 types of data per pixel.

Therefore, in this case, N of N gradations is "64". First, the data for one line, the word cycle data 444 corresponding to the first STB signal B1, is transferred to the shift register 234, and the latch signal 235 causes the latch circuit 233 to transfer to the shift register 234. Next, the strobe signal B1 is output, and the heating element to which the C data "'1°" is output is driven by the pulse width of B1. During this heat generation drive, the next gradation data 4
44 is input to the shift register 234, and the STB signal 4
45 falls, it is latched into the latch circuit 233 by the latch signal 235. Thus, the STB signal is then output during B2. This kind of operation was performed 64 times (STB
Signals B1 to B64) are executed and recording for one line is completed.

That is, the gradation conversion decoder 440 manually inputs the image data,
When the value of the mth pixel data of the line to be recorded in the image is ``20'', the mth stage of the shift register 234 corresponding to the position of the pixel data is
While referring to the value of the gradation counter 441, the first 20 pieces of data are ゜゜1゜゛, and the second half 44 (64-20).
Data 444 such that each piece of data becomes ``0'' is output 64 times in total.

However, at this time, it goes without saying that data is set in the other stages of the shift register 234 in accordance with the gradation level of the corresponding pixel.

At this time, each strobe signal STB is
The pulse width is changed depending on the number of times the TB signal is output. The strobe signal generation circuit 44 executes such pulse width adjustment of the strobe signal STB.
It is 2. As described above, this strobe signal generation circuit 442 receives the gradation data 444 corresponding to the type of ink sheet 32 from a corresponding ROM table, etc.
The width and period of 45 are adjusted.

FIG. 13 is a flowchart showing the recording process in the thermal transfer recording apparatus of the embodiment, which is stored in the ROM of the CPU 38.

Once the image data is manually input in step S1, the process proceeds to step S2, where the image data is stored in the buffer memory 35. In step 83, the recording paper is lifted up from the cassette 1]0 and conveyed to the recording position, and in step S4, the ink sheet 32 is conveyed so that the desired position of the ink sheet 32 is in the recording position. . Next, the process advances to step S5, and the motor 131 is driven to lower the thermal head 3X.

In step S6, one line of pixel data is read out from the pixel memory 35 and output to the head drive pulse control circuit 37 through the conversion table 36. This allows the first
-key data 444, latch signal 235, and strobe signal STB are output at the timing shown in FIG.

As a result, the thermal head 31 generates heat, and transfer recording is performed on the recording paper. Next, the process advances to step S7, where the recording paper and ink sheet 32 are conveyed by one line, and step S7 is carried out.
At step 8, check whether the recording process for one page has been completed. If the recording of page l has not been completed, the process returns to step S6, the next line of pixel data is read out from the buffer memory 35, and the above-described recording process is performed again.

In the case of color recording, the recording data of each color is recorded one page at a time, and each time the recording of each color is completed, the next recording step is carried out to transport one colored part to the recording position, and the recording paper is also transferred. Further, the platen 34 is rotated once and returned to its original position, and recording is performed in a different color.

By performing this operation for three colors, for example Y, M, and C, color recording can be performed on recording paper. Further, the gradation width of the gradation data 444, the pulse width of the strobe signal STB, etc. may be changed depending on the type of ink sheet 32 or recording sheet used.

As explained above, according to this embodiment, by providing a conductor part within the heating element of the thermal head,
Formed so that there is a difference in the current density flowing through the heating element,
By making the glaze layer in the portion where the current density is high protrude and have a convex shape, there is an effect that the heat generating area can be controlled easily, that is, gradation expression can be easily achieved.

By changing the transfer area by changing the heat generating area of the thermal head in accordance with the gradation level of image data, it is possible to provide a thermal transfer recording device with good gradation reproducibility.

[Effects of the Invention] As explained above, according to the recording head of the present invention, since the recording density can be reliably changed by changing the printing energy, there is an effect that it is suitable for recording intermediate tones.

Further, according to the thermal recording device of the present invention, multivalue recording is possible,
This has the effect of easily realizing multi-gradation recording.

[Brief explanation of the drawing]

Figures 1 (A) to (C) are diagrams showing the shape of the thermal head of the first embodiment, Figure 2 is a diagram showing how the thermal head of the embodiment is used, and Figure 3 (A) is the diagram showing the shape of the thermal head of the first embodiment. Figure 3 (B) is a diagram showing the current flowing through the thermal head in the example of Figure 3 (A) (7) Figure 3 (C )
is a diagram showing the thermal transfer area of the thermal head of the first embodiment, FIG. 4 is a diagram showing the relationship between printing density and printing energy in the thermal head of the embodiment, and FIG. 5 is a diagram of the thermal head of the second embodiment. Figures 6(A) to (C) are diagrams showing the thermal transfer area with respect to the impression energy applied to the thermal head of the second embodiment, and Figure 7(A) is the diagram of the third embodiment. FIG. 7(B) is a diagram showing the current distribution of the thermal head shown in FIG. 7(A), and FIGS. 8(A) to (C) are diagrams showing the shape of the thermal head of the third embodiment. FIG. 9 is a block diagram showing a schematic configuration of a thermal transfer recording apparatus using the thermal head of the embodiment, and FIG. 10 is a schematic configuration of a head drive pulse control circuit. 11 is an equivalent circuit diagram showing the structure of the thermal head, FIG. 12 is a diagram showing the timing of signals applied to the thermal head, and FIG. 13 is a flowchart showing the recording process in the thermal transfer recording apparatus of the embodiment. , Figure 14 (A) is a diagram showing the relationship between printing energy and recording density using a conventional thermal head, and Figure 14 (B) is a diagram showing the shape of the electrode and heating element in the conventional thermal head, as well as the position of the heating element. FIG. 6 is a diagram showing the corresponding temperature distribution. In the figure, 11... heating element, 12... electrode, 12a...
...Common electrode, 12b...Individual electrode, 13...Alumina substrate, 14...Glaze layer, 15...Resistance layer,
16... Electrode layer, 17... Wear-resistant layer, 18... Conductor part, 19... Conductor layer, 21... Conductor part, 31...
・Thermal head, 32... Ink sheet, 34...
・Platen roller, 35...Buffer memory, 36・
...Image data conversion table, 37... Head drive pulse control circuit, 38... CPU, 39... Display unit,
106.123 131139...Motor, 110
...Cassette, 235...Latch signal, 440...
- gradation conversion decoder, 442... strobe signal generation circuit, 444... gradation data, 445... STB signal. Patent Mountain Requester Canon Co., Ltd. rtsu rBq 0 no ρ ku r 0 sect 13 U Sonoro 1 Furuya (mJ) Figure 4 (A) Ilt Shi Figure 14 (B)

Claims (4)

[Claims] (1) A plurality of heating resistors arranged in a row, and an electrode for supplying electrical energy to each of the plurality of heating resistors, the width of the heating resistor being wider than the width of the heating resistor. A recording head comprising at least one narrow narrow portion, the narrow portion being formed by a conductor or a conductor portion provided on the heating resistor. (2) The recording head according to claim 1, wherein the glaze layer near the narrow portion has a shape protruding from the periphery with an apex near the connection point. (3) comprising a plurality of heating resistors arranged in a row and an electrode for supplying electrical energy to each of the plurality of heating resistors, and in contact with the electrode within the heating resistor; A recording head characterized in that a conductor portion having a much lower resistance value than the heating resistor is provided at a position where the heating resistor is not in contact with the heating resistor. (4) A plurality of heating resistors arranged in a row, and an electrode for supplying electrical energy to each of the plurality of heating resistors, the heating resistor being wider than the width of the heating resistor. a recording head including at least one narrow narrow portion, the narrow portion being formed of a conductor or a conductor provided on the heating resistor; gradation determining means for determining the gradation of image data to be recorded by each heating element of the recording head in accordance with the gradation, and recording means for recording by energizing each heating element of the recording head according to the gradation. A thermal recording device comprising: