JP2894416B2 - Thermal recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording apparatus for transferring ink on a melting or sublimation type ink sheet to recording paper by heat, and is applicable to printers, copiers, facsimile machines and the like.

[0002]

2. Description of the Related Art A thermal recording apparatus using a thermal head is:
Due to advantages such as a simple mechanism, high reliability and excellent maintainability, thermal recording is mainly used for facsimile, and thermal transfer recording is mainly used for color printers. As the thermal transfer recording apparatus, there are a fusing type printer using a fusing type ink sheet and fusing type recording paper, and a sublimation type printer using a sublimation type ink sheet and sublimation type recording paper.

There are two types of fusion-type recording systems: a fusion-type binary recording system in which only one-dot recording and two-level recording are performed, and a fusion-type multi-value recording system in which the recording area can be changed for each dot. . When gradation expression is performed by the fusion type binary recording method, one dot is arranged in a matrix and the dot area in the dot is changed. Both the fusion type multi-value recording method and the sublimation type recording method can perform analog halftone recording. The conventional halftone recording method is disclosed in, for example,
FIG. 27 is a waveform diagram of an energizing pulse applied to each heating resistor constituting a thermal head in a conventional halftone recording method. In FIG. 27, tw is the pulse width of the energizing pulse, tp is the repetition period of the energizing pulse, and N is the number of energizing pulses (here, 3
). The number of the energizing pulses is selected and set in advance corresponding to the density for each gradation level.

By applying the energizing pulses of the pulse number corresponding to each gradation to each heating resistor in this manner, the ink corresponding to the energy corresponding to the pulse number is sublimated or melted, and the halftone recording of each density is performed. Done. And
Normally, a corresponding energizing pulse is applied collectively or separately to each of the heating resistors arranged side by side in the thermal head for one line to perform recording for one line, and the recording paper is fed in the sub-scanning direction at a constant speed. The recording for each line is sequentially performed to perform the planar recording.

FIG. 28 shows an example of a strobe signal when the thermal head is driven in a time sharing manner. FIG.
The strobe signals SB1 and SB2 in the case of split driving are output in parallel.

On the other hand, FIG. 29 shows the basic structure of a conventional thermal transfer recording apparatus disclosed in the document "Thermal Recording Technology" edited by Trikeps Publishing Division (No. 117, published August 10, 1990, pp. 63-67). FIG. 7 is a configuration diagram, where 71 is a thermal head, 72 is an ink sheet, 73 is a recording paper, and 74 is a platen roller. Here, the ink sheet 72 is
It comprises a heat-resistant lubricating layer 75, a base film 76, and an ink layer 77 made of a pigment and a binder. The ink sheet 72 and the recording paper 73 having good flatness are applied to the thermal head 7.
1 and the platen roller 74, and a plurality of heating resistors (not shown) in the thermal head 71 are heated to melt the ink layer 77 to obtain a desired recorded image.

As described above, a method of transferring the ink applied to the ink sheet to recording paper by using heat includes a fusion recording method and a sublimation recording method using a sublimable dye as the ink. The fusion type multi-value recording method has excellent gradation characteristics because the area of one dot is changed in an analog manner, and is suitable for printing a full-color image. However, when recording is performed on plain paper having irregularities to some extent by this method, there is a problem that there are many transfer failures particularly at a low gradation. For this reason,
When this method is used, a special coating must be applied to the recording paper so as to improve the adhesion to the ink, and the recording paper must have small irregularities. for that reason,
The cost of the recording paper increases and the running cost increases.
Also, since it is a method of changing the area of one dot in an analog manner, it is suitable for offset printing, but not for gravure printing.

Next, a sublimation type recording method is a method in which the density of one dot can be changed in an analog manner. In the case of n gradations, the ink sheet is yellow (Y),
When composed of three colors of magenta (M) and cyan (C), n ³
Color expression is possible, and when n = 256, about 167
It can express 100,000 colors. Therefore, it has a very excellent gradation, and has been used for natural images such as photographs or CG (computer graphics). However, in this method, the dye is sublimated by heat and transferred to a plastic or the like. Therefore, the ink sheet and the recording paper become expensive, and the running cost becomes higher than any of the fusion type. In addition, since the method is a method in which the density of one dot is changed, when the method is used for a printing composition, it is suitable for a gravure printing composition but not for an offset printing composition.

Further, the sublimation type recording system requires special paper while having high image quality, and the fusion type binary recording system has a feature that it is difficult to express halftones, but is capable of high-speed and plain paper recording. In general, two devices are generally used depending on the application, despite the same thermal transfer recording method. In order to eliminate such disadvantages, a printer combining these methods can be considered. Conventionally, as such a printer, using an ink sheet in which the ink for the melting type and the ink for the sublimation type are alternately formed,
There are printers that can transfer color gradation images and lines and characters. A specific description is given below.

FIG. 30 shows, for example, Japanese Patent Application Laid-Open No. 62-179975.
FIG. 1 is a configuration diagram of an ink sheet of a fusing / subliming printer used in a conventional thermal transfer recording apparatus disclosed in Japanese Patent Application Laid-Open Publication No. H11-209,837. 30, 72 is an ink sheet, 79y, 79m,
79c is yellow (Y) applied on the ink sheet,
Magenta (M), cyan (C) sublimable ink, 80 is black (Bk) fusible ink, 81y, 81m, 81
c and 81b are marks for distinguishing four colors by the number of marks. The ink sheet 72 has three sublimable ink surfaces 79y, 79m, and 79c of yellow, magenta, and cyan.
Black (Bk) fusible ink surfaces 80 are sequentially formed. The ink discrimination marks include 82a indicating sublimability and 82b indicating fusibility.

FIG. 31 is a diagram showing the construction of a melting / sublimation printer using the ink sheet for both melting and sublimation shown in FIG. 30, FIG. FIG. 3 is an explanatory diagram of the energizing time and the line feed time of the melting / sublimation printer.

Since the thermal characteristics of the fusible ink and the sublimable ink are different, the energization time of the thermal head 71 shown in FIG. 31 needs to be different as shown in FIG. For example, it is necessary to provide a difference such as a variable range of 5 ms for the meltable ink and 5 to 20 ms for the sublimable ink.

Next, the operation will be described with reference to FIG. The color identification marks 81y, 81m, 81c on the ink sheet 72,
The sensor 81 and the ink discrimination marks 82a and 82b are detected by sensors 86 and 87, respectively. In the case of image input, the image data is separated into three colors of yellow, magenta, and cyan by the color conversion unit 88 and stored in the memory 89. In the case of character / line input, the image is directly stored in the memory 89. The image data stored in the memory 89 is stored in the image data reading unit 9.
0, and is input to the energization control unit 92 via the gradation conversion unit 91. In the case of character / line data,
The data is read by the line data reading unit 93 and is input to the energization control unit 92 as it is. Note that the energization time and the line feed time differ between the image data and the character / line data as shown in FIG.

[0014]

Since the conventional thermal recording apparatus which combines a melting type and a sublimation type is configured as described above, only a gradation image or only an image such as a line and a character is continuously printed. In this case, the meltable ink or the sublimable ink portion of the ink sheet is wasted and is consumed more than the ink sheet is actually used. As a result,
Running costs were doubled or more, and users suffered significant disadvantages.

Further, a complicated circuit for discriminating image data and character / line data is required, which not only increases the running cost but also the cost of the apparatus itself. Be impaired. In addition, the sublimation type recording paper uses special paper, and it is about 20 times as expensive as the fusion type recording paper, and can print images without gradation (such as characters).
However, there is a problem that the running cost is high even when printing is performed.

Further, when the melting type recording system and the sublimation type recording system are used together, there is a problem regarding the size of the heating resistor of the thermal head. First, the sublimation type recording method is used. Since the transfer by this method is a recording method in which the density within one dot is changed as shown in FIG. 34, the temperature distribution of the heating resistor of the thermal head must be uniform within the dot. It is desirable that the shape of the heating resistor be longer in the vertical direction than the horizontal direction in order to prevent blurring and increase the maximum density.

On the other hand, since the melting type recording method is a recording method in which the area of one dot is changed as shown in FIG. 35, the temperature distribution of the heating resistor of the thermal head is desirably concentric with respect to one point. Further, it is better that there is a certain temperature difference in order to improve dot cutting and stability. In addition, there is a surface that is easily affected by heat of surrounding dots. Therefore, in the fusion type recording method, it is preferable that the length of the heating resistor of the thermal head be the same as the length in the horizontal direction.

Due to these characteristics, the heating resistor shape generally used in the sublimation recording system is horizontal: vertical = 1:
When the thermal head of 2.5 is used in the melting type recording method,
Blurring tends to occur at the time of low gradation, and the density increases sharply with respect to the applied energy, so that it is difficult to perform fusion recording. In addition, the size of the heating resistor is set to horizontal: vertical =
When the ratio is set to 1: 1, there is no problem in the fusion type recording system, but when the sublimation type recording system is used, blurring at the time of low gradation is apt to occur, and the maximum density is low, so that it is difficult to perform the sublimation type recording. Therefore, there is a problem that the two types of the recording method, the fusion type recording method and the sublimation type recording method, cannot be simultaneously satisfied by using any of the thermal heads.

When halftone printing is performed by a conventional thermal printing apparatus, there is a problem that density unevenness occurs depending on the driving method of the thermal head. For example, 204
A thermal head having eight heating resistors is driven by two divisions (the left side of the thermal head is driven by a strobe signal SB1 and the right side is driven by a strobe signal SB2). When the right half of the gradation (recording pattern B) was recorded, the recording densities were 1.0 and 1.1, respectively, as shown in FIG. 36, and the recording pattern B was darker by about 10 gradations.

In order to investigate the cause, the current at the time of driving the thermal head was measured, and the current behavior was measured. FIG. 37 shows the current behavior results. First, looking at the current waveform in the recording pattern B, when the strobe SB2 falls, a current flows through the heating resistor of the thermal head (ink is transferred by Joule heat), and the strobe SB2
It can be seen that the current stops flowing at the rise of. Here, the current does not flow at the falling edge of the strobe SB1 because there is no data that causes the thermal head to generate heat (the number of gradations is 0).

On the other hand, in the case of the recording pattern A which causes all the heating resistors to generate heat, a current (a in FIG. 37) flows with the fall of the strobe SB1, and the current (a in FIG. 37) is switched from the strobe SB1 to the strobe SB2. I)
After a while, the predetermined current (FIG. 37)
(B) flows and the current (b in FIG. 37) stops flowing as the strobe SB2 rises. It should be noted here that the current waveform corresponding to the strobe SB2 is different between the case of the recording pattern A (b in FIG. 37) and the case of the recording pattern B (c in FIG. 37). Difference in recording density (density unevenness) accumulated for each pulse signal
Can be presumed to appear.

Here, the strobe SB1 and the strobe S
Consider that the current is hard to flow at the boundary of B2. In the conventional halftone recording method, the strobe SB
The strobe SB2 falls immediately after 1 rises. (The interval between strobe SB1 and strobe SB2 is almost equal to 0). Normally, a driver IC for driving a heating resistor is incorporated in the thermal head. However, the strobe waveforms SB1 and SB2 are changed from a solid rectangular wave to a dotted line as shown in FIG. The result is a dull waveform. That is, the falling of the pulse signal is delayed by 100 ns, and the rising of the pulse signal is delayed by 200 ns.
A waveform that delayed by ns was obtained. These values gave substantially the same results when measured with another thermal head.

The delay time difference causes the strobe waveform to overlap. This means that the power supply capacity supplied to the thermal head exceeds the allowable range. As a result, it is considered that the power supply voltage drops and the above phenomenon occurs. If the power supply capacity is increased in order to solve the above-mentioned phenomenon, an increase in cost is inevitable, and the merits of divided drive are reduced by half.

On the other hand, if the pulse width control is performed when the strobe control is divided into two, the pulse applied to the thermal head is as shown in FIG. At this time, the reason why the pulse applied to the first gradation is extremely longer than the second and subsequent gradations is that the ink is transferred at the density of the first gradation from a state where the heating resistor is cooled. The energy until the temperature reaches the density of the first gradation to the density of the second gradation is 3 to the density of the second gradation.
This is because the density is extremely higher than each of the gradation densities. According to FIG. 38, in this case, compared to the strobe A, the strobe B has a shorter time from the end of the first gradation pulse to the start of the second gradation pulse. Therefore, the density of the dot energized by the strobe B is higher than that of the dot energized by the strobe A, and density unevenness occurs.

If the number of pulses is controlled, the pulses applied to the thermal head are as shown in FIG. In this case, there is almost no density unevenness due to the difference in the amount of heat stored between strobe A and strobe B, but the basic unit of increase / decrease is the pulse width unit. In this case, in order to increase or decrease in small units, the width of each pulse may be narrowed, but if so, the driver IC of the thermal head cannot follow the pulse and the operation becomes unstable. Therefore, the pulse width is 5μ
s, and can be increased or decreased only in units of 5 μs.

Next, the printing state when the fusion recording method is performed is as shown in FIG. At this time, when the dots such as the rightmost one in FIG. 40 come close to each other, the transfer becomes unstable due to the thermal influence of the surrounding dots, and the four dots in the upper left of FIG. In some cases, transfer was performed by sticking to surrounding dots. Therefore, there is a problem that an image is deteriorated.

Next, the recording medium differs between the melting type recording method and the sublimation type recording method. Therefore, in the case of a dual-purpose printer in which a plurality of ink sheets can be mounted, the ink sheet is for the sublimation type recording method and the recording paper is for the fusion type recording method, or vice versa. May be caused by Further, even in the same method, there is a problem that if the smoothness of the recording paper is low, the recording sensitivity is deteriorated, and image quality deterioration such as fading of the image or unprintable due to insufficient applied energy occurs.

Further, when recognizing the recording paper, a recognition mark must be added to each of a plurality of types of recording paper, and a sensor must be provided in accordance with the type of the recording paper. The cost is high. Furthermore, since a mark must be added to perform sensing, it is not possible to perform recording on paper other than designated paper, and even if a user prepares a recordable paper in principle, recording cannot be performed because there is no mark. There was a problem.

The amount of data to be actually recorded differs between the fusion type recording method and the sublimation type recording method. For example, in the case of the melting type recording method or the sublimation type recording method, two pixels are used for one pixel.
If the expression of 56 gradations is performed, the data amount required for one pixel is 8 bits, and since the fusion halftone recording is more sensitive than the sublimation type, the amount of data transferred to the thermal head is reduced, High-speed printing is possible.

Therefore, it is conceivable that a high-speed printing mode is provided only for the fusion halftone recording to perform 64-gradation recording. At this time, the data amount is 6 bits per pixel. Therefore, when printing the same image data using different recording methods, it is necessary to convert the image data suitable for each mode. This causes a need for data conversion suitable for each method on the data sending side, for example, when it is desired to perform test printing with a method having a low running cost, and this is one of the problems of a combined printer. I have.

If the recording paper has a different thickness or a different friction coefficient, the pressure applied to the paper feed roller of the paper cassette must be changed to apply a pressure corresponding to the paper thickness and the friction coefficient. There was a problem that it was easy to cause paper jam and paper feeding.

FIG. 42 is a configuration diagram of a recording section of a conventional thermal recording apparatus. In the figure, 1 is a thermal head, 2 is a recording paper, 3 is an ink sheet, and 4 is a platen roller. r
Is the radius of the platen roller, and r 'is the radius when the thickness of the recording paper is added to the diameter of the platen roller. Hereinafter, description will be made with reference to FIG. When the recording paper 2 is conveyed by the platen roller 4 when a plurality of recording papers are used and the thickness of the recording paper is different, r ′ changes, and recording is performed even when the platen roller 4 is rotated by the same rotation amount. The transport amount of the paper 2 changes.

For example, r = 16 mm, r '= 16.2 mm
At the time of A4 (width × length: 210 × 297 mm, thickness: 2
If the recording paper 2 is conveyed (00 μm), the number of rotations of the platen roller 4 is 297 回 転 32.4π = 2.9178 rotations. Here, if the paper thickness is 100 μm, r ′ = 16.1 mm
The movement amount of the recording paper 2 at this time is 32.2π × 2.9178 = 295.2 mm, and the maximum value of the deviation amount due to the paper thickness is 297−295.2 = 1.8 mm. As described above, there is a problem that the recording position is shifted when the paper thickness is different.

When the image data to be recorded by the user is smaller or larger than the maximum print size of the recording apparatus, and when printing is performed by enlarging or reducing the maximum print size, the image size and the maximum size of the image to be recorded by the user are determined. There is a problem that the user has to calculate the magnification of the data from the print size and input the data by himself.

The present invention has been made in order to solve the above-mentioned problems, and by using both a melting type recording method and a sublimation type recording method, an optimum image quality and cost recording method can be selected. It is another object of the present invention to obtain a thermal recording device with improved operability.

[0036]

According to a first aspect of the present invention, there is provided a thermal recording apparatus comprising: a thermal head having a plurality of heating resistors arranged in a horizontal direction; Means for transferring the applied ink to the recording paper by the heat of the heating resistor, a setting unit for setting the melting type mode and the sublimation mode, and a heating unit of the thermal head according to a signal from the setting unit. An energization control unit for controlling applied power is provided. The heating resistor has a horizontal length of 0.35 to 0.75 with respect to a pitch interval of the heating resistor, and a vertical length of the heating resistor in the horizontal direction. It is 1.5 to 2.5 times the length.

In the thermal recording apparatus according to a second aspect of the present invention, the plurality of heating resistors are divided into a plurality of groups in the horizontal direction, and the number of divided groups of energization control signal lines are provided. Heating is performed by sequentially applying a pulse as electric power to the heating resistor by means of an energization control signal line, and the interval between pulses for each energization control signal line is set to 100 to 500 ns.

According to a third aspect of the present invention, a thermal recording apparatus performs both pulse number control and pulse width control with an energization control signal via an energization control signal line.

According to a fourth aspect of the present invention, there is provided a thermal recording apparatus comprising: a melting type ink sheet coated with an ink of 2.5 g / m ² or less; and a recording paper provided with an ink absorbing layer on the surface. It is.

According to a fifth aspect of the present invention, there is provided a thermal recording apparatus, comprising: a melting type ink sheet in which a surface coated with an ink of 2.5 g / m ² or less and a surface coated with an ink absorbing material are formed; Means for generating data for transferring the ink-absorbing substance to the recording paper before the image is transferred to the recording paper.

According to a sixth aspect of the present invention, there is provided a thermal recording apparatus in which an ink layer of a melting type ink sheet is provided with an ink absorbing layer for absorbing the ink to be transferred next. is there.

The thermal recording apparatus according to a seventh aspect of the present invention compares the signal of the setting section for setting the fusion type mode and the sublimation type mode with the attached recording medium, and when both coincide, the recording is performed. The system is provided with a means for starting the operation, warning the user if the values do not match, and stopping the start of the recording operation.

The thermal recording apparatus according to claim 8 of the present invention includes means for identifying the type of recording paper by its optical characteristics, and means for changing the recording energy according to the identification result of the identification means.

A thermal recording apparatus according to a ninth aspect of the present invention includes means for assigning to any of the n gradation recording conditions when expressing gradations of n gradations or less.

According to a tenth aspect of the present invention, there is provided a thermal recording apparatus including means for changing a feed amount of one line according to a thickness of a recording sheet.

The thermal recording apparatus according to the eleventh aspect of the present invention includes means for automatically enlarging or reducing input data to a maximum print size capable of recording, or performing both enlargement and reduction.

[0047]

In the thermal recording apparatus according to the first aspect of the present invention, the power supply control section controls the power applied to the heating resistor of the thermal head in accordance with a signal from the setting section for setting the melting mode and the sublimation mode. I do. Further, the heating resistor has a horizontal length of 0.35 with respect to the pitch interval of the heating resistor.
0.75, and the vertical length is 1.5 times the horizontal length.
Since it is 2.5 times, blurring at the time of low gradation is eliminated, and halftone recording with good dot breakage and stability is performed.

In the thermal recording apparatus according to a second aspect of the present invention, the energization control section sets the interval between the unit pulses of at least two energization control signals to 100 to 500 ns.
By opening, the polymerization between the energization control signals can be relaxed, and recording without density unevenness is performed.

In the thermal recording apparatus according to the third aspect of the present invention, by controlling the control of at least two energization control signals by a combination of the pulse number control and the pulse width control, recording without density unevenness is performed. .

In the thermal recording apparatus according to the fourth aspect of the present invention, the fusible ink is absorbed by the ink absorbing layer provided on the surface of the recording paper.

In the thermal recording apparatus according to the fifth aspect of the present invention, a substance absorbing the ink is transferred to the recording paper before the ink is transferred to the recording paper.

In the thermal recording apparatus according to the sixth aspect of the present invention, the previously transferred ink absorbs the next transferred ink.

In the thermal recording apparatus according to the seventh aspect of the present invention, the signal of the setting section for setting the fusion type mode or the sublimation type mode is compared with the attached recording medium. The recording operation is started, and if they do not match, a warning to that effect is given and the start of the recording operation is stopped.

In the thermal recording apparatus according to the eighth aspect of the present invention, the type of the recording paper is identified based on the optical characteristics of the recording paper, and the optimum energy is applied to the recording paper.

In the thermal recording apparatus according to the ninth aspect of the present invention, when expressing gradations equal to or less than n gradations, the recording conditions are assigned to any of the n gradation recording conditions.

In the thermal recording apparatus according to the tenth aspect of the present invention, the paper feed amount of one line changes according to the thickness of the recording paper.

In the thermal recording apparatus according to the eleventh aspect of the present invention, recording of the maximum printable size in the maximum print mode is automatically performed.

[0058]

【Example】

Embodiment 1 FIG. FIG. 1 is a configuration diagram of a thermal recording apparatus that combines a melting type recording method and a sublimation type recording method. In FIG. 1A, 1 is a thermal head, 2 is a recording paper, 3 is an ink sheet, 4 is a platen roller, 5 is a color conversion unit that absorbs a difference in the hue of ink on the ink sheet, and 6 is a memory. 7
Has a function of binarizing multi-valued data by the gradation conversion unit and outputting the binarized data to the thermal head 1, and is not necessary when the thermal head 1 can directly receive the multi-valued data. Numeral 8 denotes a recording method selection signal generating means as a setting unit for selecting one of the melting type recording method and the sublimation type recording method, and 9 denotes an energization control for outputting an optimum pulse to the thermal head 1 according to the recording method and gradation. Department. Reference numeral 10 denotes a paper transport motor control unit, and reference numeral 11 denotes a paper transport motor. In FIG. 1B, reference numeral 1 denotes a thermal head, and 1a denotes a heating resistor disposed in a lateral direction of the thermal head 1.

The thermal head 1 is divided into a thick film type and a thin film type depending on the manufacturing method. The thick film type is advantageous in cost because the manufacturing method is simple. On the other hand, although the thin film type is disadvantageous in cost, it is excellent in image quality and is used in most color printers. Heating resistor 1 in both cases
The shape of a depends on the resolution. For example, if the resolution is 30
At 0 DPI, the main scanning direction (hereinafter, referred to as horizontal direction) is actually 80 μm, and the sub-scanning direction (hereinafter, referred to as vertical direction).
Has a shape of about 100 μm. On the other hand, the thermal head 1 used in sublimation recording has the same horizontal length but a long vertical direction of 220 μm.

This difference comes from the driving method of the thermal head 1. That is, in the case of the sublimation type, the thermal head 1 is driven by a large number of pulses / line, whereas in the case of the fusion type, the thermal head 1 is driven by about 1 to 4 pulses / line. There is an item of pulse resistance in the standard of the thermal head 1, and the sublimation type heating resistor 1a
In order to prolong the service life of the heater, the area of the heat generating resistor 1a is made larger than that of the molten mold to reduce stress. Also,
The lengthening in the vertical direction is intended to overlap with the next line and to increase the concentration even at the same energy.

FIG. 2 shows that the horizontal length of the heating resistor 1a of the thermal head 1 at a pitch of 300 DPI is 50 μm.
These are energy-density characteristics when the heating resistor 1a is set to 60 μm, 70 μm, and the longitudinal length of the heating resistor 1a is set to 100 μm, 120 μm, and 140 μm. From FIG. 2, the heating resistor 1a is shown.
It can be seen that, as the length in the horizontal direction increases, the density at the time of low energy becomes lower and the density rises sharply. The reason will be described with reference to FIG. FIG. 3 is an example of the heat distribution of the heating resistor 1a and its surroundings. FIG. 3 shows that the heat distribution inside the heating resistor 1a is moderate.

Therefore, when the melting point of the ink covers the gentle portion, the shape of the dot becomes unstable or blurred. Also, the heating resistor 1a
The heat distribution outside is sharp, and when this portion is over the melting point of the ink, the shape of the dot is stable. In other words, if the area of the heat generating resistor 1a is large, the unstable portion of the heat distribution becomes large, causing unstable dot shapes and blurring at low gradations, and thus blurring at low gradations. In addition, when the area is large, the peripheral dots are easily affected by the heat, and when the energy is high, the density is rapidly increased due to the peripheral heat.

In this experiment, at a pitch of 300 DPI, the heating resistor 1 a having a large length in the horizontal direction was 60
It was found that the one having a thickness of μm was the limit in terms of image quality, and the one having a thickness of 70 μm was not practical. Therefore, it can be said that the limit of the pitch in the horizontal direction of the heating resistor 1a in the larger direction is 60 方向 83 = about 0.75 because the pitch width of 300 DPI is 83 μm.

FIG. 4 shows the above-mentioned 50 × 100 μm,
Heating resistor 1a of 60 × 120 μm, 70 × 140 μm
FIG. 5 shows the energy-density characteristics when the heating resistors 1a are heated every other in the horizontal and vertical directions using the thermal head 1 of FIG. In this case, the pitch is 300
This is considered to be the same as when 150 DPI, which is half of the DPI, is used. From FIG. 4, it can be seen that the sensitivity decreases in the order of 70 μm, 60 μm, and 50 μm. Especially 50 μm
No one could reach the highest concentration of 1.5. This is because the area of the heating resistor 1a is too small,
This is because the sensitivity became extremely poor.

In this experiment, it was found that the size of 60 μm, which could reach the maximum density of 1.5, was the limit in the smaller direction from the point of sensitivity. Therefore, it can be said that the limit of the pitch in the direction in which the horizontal length of the heating resistor 1a is smaller than the pitch is 60 ÷ 167 = about 0.35 because the pitch width of 150 DPI is 167 μm.

FIG. 6 shows that the horizontal length of the heating resistor 1a of the thermal head 1 having a pitch of 300 DPI is 50 μm.
m, length in the vertical direction is 50 μm, 75 μm, 100 μm
It is the result of observing the growth of the dots at m, 125 μm and 150 μm. As can be seen from FIG.
In the case of m, dots are easily connected from the side, and 7
At 5 μm, the connection was somewhat difficult, and at 100 μm, the shape was almost a circle.

In the case of 50 μm, visible horizontal streaks were conspicuous, and there was a problem in practical use. In the case of 75 μm,
Some horizontal stripes were visible, but they were of sufficient level for practical use. Further, when the thickness is 125 μm, it is easy to connect vertically,
In the case of 50 μm, a phenomenon was observed in which the image was vertically connected from the time of low gradation. In the case of 125 μm, the vertical streak was slightly visible, but it was of a practically usable degree, whereas in the case of 150 μm, the vertical streak was so bad that the image was unsuitable for practical use.

FIG. 7 shows the energy-density characteristics of the thermal heads 1 having the respective heating elements. As can be seen from the figure, the one with 150 μm showed a drastic change in density, making it difficult to obtain a gradation. From these results, it is found that the length of the heating resistor 1a in the vertical direction can be practically used is 75 μm.
It was found that the ratio of 1.5 to 2.5 was appropriate for the horizontal length of 50 μm.

Next, the operation will be described with reference to FIG.
First, the recording method signal generation means 8 generates a recording method selection signal indicating whether the recording method is the fusion recording method or the sublimation recording method, according to the user's selection. This selection signal is sent to the color conversion unit 5, the power supply control unit 9,
The data is input to the paper transport motor control unit 10. After that, the image data is input, the color conversion unit 5 performs color conversion in accordance with the above-mentioned recording method selection signal, and stores the data in the memory 6. After being subjected to gradation conversion by the gradation conversion section 7 to be binarized, it is outputted to the thermal head 1. Next, in accordance with the recording system selection signal generated by the recording system selection signal generating means 8, the conduction controller 9 outputs an energizing pulse optimal to the thermal head 1 to the thermal head 1. At the same time, the paper transport motor control unit 1
By 0, the paper transport motor 11 is driven according to the recording mode selection signal. Then, ink is transferred from the ink sheet 3 to the recording paper 2 and recording is performed.

The recording system selection signal generating means 8
Is a means for setting by a button or switch of the main body or an external input such as a host computer. Further, in this case, the color conversion section 5 and the memory 6 are provided in the thermal recording apparatus, but the color conversion section 5 and the memory 6 may be provided in a host computer (not shown).

Embodiment 2 FIG. Next, another invention will be described. Before describing the operation of the energization control unit shown in FIG. 8, the principle of the present invention will be described with reference to FIGS. In FIG. 9, t1 is the conduction pulse width of the strobe signal SB1, t2 is the time from the fall of the strobe signal SB1 to the fall of the strobe signal SB2, t3
Is the conduction pulse width of the strobe signal SB2, and t4 is the strobe signal SB1 from the fall of the strobe signal SB2.
It is the time until the fall.

Further, t5 is the time from the rising of the strobe signal SB1 to the falling of the strobe signal SB2, and t6 is the time from the rising of the strobe signal SB2 to the falling of the strobe signal SB1. t5
And the time of t6 is the interval between unit pulses.

FIG. 10 shows the relationship between the unit pulse and the interval between the unit pulses and the recording density. The horizontal axis represents t5 or t6.
And the vertical axis represents the recording density. Here, the method of changing t5 and t6 is to make t1 constant and change t2. The results were as follows.

(1) In the case of the recording pattern B of the right half of 128 gradations shown in FIG. 36, the recording density gradually decreased when the interval of t5 or t6 was widened. This is because the thermal efficiency became poor, and shows the same effect as narrowing t1.

(2) In the recording pattern A of a 128-gradation all black pattern shown in FIG. 36, the density once increased when the interval of t5 or t6 was increased, but gradually decreased when the interval exceeded 100 ns. This can be considered as follows. First, the increase in the recording density is thought to be due to the fact that the strobes SB1 and SB2 are no longer overlapping, and the influence of the drop in the power supply voltage has been reduced. On the other hand, the decrease in the recording density is the same as the reason according to the above (1). If the interval between t5 and t6 is simply widened, the recording density will not be the predetermined density.
It is necessary to widen the energizing pulse width t1 so that a desired density can be obtained. However, even if the energizing pulse width t1 is increased, if the interval between t5 and t6 exceeds 500 ns, there is a problem from the viewpoint of recording time and power consumption.

From the above, it can be seen that an image without density unevenness can be obtained if the interval between the unit pulses is 100 to 500 ns. In the above-described example, the case of two-division recording is shown, but the same applies to the case of three-division recording or more. Even if the interval between t5 and t6 is made different, for example, t5 = 100 ns and t6 = 125 ns, the same effect is obtained.

Next, the operation will be described with reference to FIG. FIG. 8 is a configuration diagram of an energization control unit that drives the thermal head. In the figure, 35 to 38 are pulse width counters, 39 is a pulse number generating means in which the number of pulses for each gradation is stored in the ROM, 40 is a pulse number control unit, and 41 is a predetermined value of a strobe pulse width. Counter 35
This is a pulse width setting means having .about.38. Counter 35
38 are for t1 to t4 shown in FIG. As an example, the counter 35 has 5 μs, the counter 36 has 5.125 μs, the counter 37 has 5 μs, and the counter 3
8. For example, 5.125 μs is set. The pulse number generating means 39 stores, for example, 20 pulses for the first gradation, 14 pulses for the second gradation,... 4 pulses for the 255th gradation. The basic pulse signal having the value set in the counters 35 to 38 is input to the pulse number control unit 40, the output (number of pulses) of the pulse number generating means 39 is input, and the set number of pulses is output. Is done.

Referring to FIG. 9, the strobe signal SB1 falls by a trigger signal (not shown), and the counter 35 and the counter 36 start measurement.
Subsequently, when the counter 35 reaches a specified value, the strobe signal SB1 rises. Subsequently, when the counter 36 reaches the specified value, the strobe signal SB2 falls, and the measurement of the counter 37 and the counter 38 is started. Subsequently, when the counter 37 reaches the specified value, the strobe signal SB2 rises, and when the counter 38 reaches the specified value, the strobe signal SB1 falls. This operation needs to be performed only for the output of the pulse number generating means 39.

In the above embodiment, four counters are provided for easy understanding. However, the configuration may be simplified such that the counter 35 and the counter 37 are shared.
Further, in FIG. 8, the number of pulses for each gradation is set using the number-of-pulses generation means 39, but a configuration in which a pulse width is set instead of the number of pulses may be used. In this case, for example, the output results of the pulse width setting means (not shown) may be input to the counter 35 and the counter 37. Further, in order to increase the interval between unit pulses, the number of counters can be reduced by incorporating a shift register or a delay IC so that the strobe signal SB2 is delayed with respect to the strobe signal SB1.

Embodiment 3 FIG. Next, another invention will be described. When the strobe control is divided into two and driven by an apparatus capable of halftone recording, there is a problem that density unevenness between strobes occurs.

As a method for solving this problem, the following 2
There are two ways. (1) When performing pulse width control, the pulse width of strobe A and strobe B is changed in consideration of the heat storage amount in advance. (2) Reduce the width of each pulse when controlling the number of pulses. In the case of (1), the pulse table is doubled, so that not only the capacity of the ROM is increased, but also the amount of work for creating the pulse table is doubled, which is disadvantageous. In the case of (2), if the response of the driver IC of the thermal head has a pulse width of 5 μs or less, the operation becomes unstable, which causes a problem. Therefore, a mixed control method of pulse width and pulse number having both advantages of pulse width control and pulse number control was created.

Next, the configuration and operation will be described with reference to FIGS. FIG. 11 is a configuration diagram of an energization control unit for performing energization control according to the present invention, and FIG. 12 is a pulse waveform of a strobe that can be generated in the configuration of FIG. In FIG. 11, reference numeral 39 denotes pulse number generating means for setting the number of pulses to be applied to the first gradation in a register; 41, pulse width setting means for storing the pulse width of a strobe in a ROM; = 5 μs, pulse width of second gradation = 9 μs, pulse width of third gradation = 7 μs
, And are read out as appropriate.
Reference numeral 42 denotes a pulse number pulse width control unit for generating a strobe pulse, and t1, t2, and t3 in FIG. 12 denote a pulse width of the first gradation, a pulse width of the second gradation, and a pulse width of the third gradation, respectively. Each corresponds.

Using the configuration of FIG. 11 as described above, a strobe as shown in FIG.
There is no difference in the amount of stored heat between the pulse and the strobe B, and the pulse can be changed in small units. Also, here 1
The mixture control of the pulse number and the pulse width is performed only for the gray scale, and the pulse width control is performed for the second and subsequent gray scales. However, the mixed control may be performed for the entire low gray scale area or the pulse number control may be performed for the low gray scale. ,
Other than that, the pulse width control may be performed.

Embodiment 4 FIG. Next, another invention will be described. When printing was performed using the fusion recording method, an image was sometimes distorted on the high gradation side. This is because, as described above, when the area of the dot increases and approaches the surrounding dots, the transfer of ink becomes unstable due to the thermal influence of the surrounding dots, and the area that should be the original space between the dots This occurs because transfer is performed on the image. This is caused by the following 3
One can be considered. When cellulose is used as the base paper, heat is transmitted along the fibers of the paper, and transfer is performed to this portion. Further, since the hardness of the recording paper is high, the ink moves around by the pressure with the platen roller. Further, heat is transmitted on the surface of the recording paper, and transfer is performed between dots.

In order to solve this problem, the ink thickness of the ink applied and the smoothness, heat insulation and cushioning properties of the recording paper were improved, and the transfer of each color of Y, M, C and Bk was performed. Improvements have been seen. However, when the transfer is performed with the two colors and the three colors superimposed, the transfer is performed on the ink, so that the effect of the above-described improvement is lost, and the image is disturbed on the high gradation side again. In order to solve this, the ink transferred at the time of transfer may be taken into the recording paper side so that the inks do not affect each other.

FIG. 13 is an energy density characteristic diagram when the thickness of the ink layer is changed. The horizontal axis represents energy, the vertical axis represents dot length, and the amount of applied ink is used as a parameter. The thermal head used had a heating resistor of 80 μm in both length and width. From this result, it can be seen that the thinner the ink thickness, the better the sensitivity and the dot length is closer to the desired value (80 μm). The thicker the ink, the lower the resolution because the heat from the thermal head spreads to the periphery. According to this result, 2.5 g / m ² from the current 3.5 g / m ²
It can be seen that m ² is more excellent in sensitivity, resolution, and gradation (gradual change in dot length). Therefore, when a recording paper having a thickness of 2.5 g / m ² is provided with a structure that absorbs the ink, the transfer can be performed without impairing the gradation even when the transfer is performed repeatedly. Was.

As one of the other requirements of the present invention, a method of providing a recording paper with an absorbing structure is to form a sponge-like space inside the recording paper and to make a fine hole in the surface to make the recording paper have an absorbing structure. Ink absorption can be realized. FIGS. 14A and 14B show the cross-sectional view and the surface state of the recording paper at that time.
Are shown below. In FIG. 14A, reference numeral 12 denotes an ink absorbing layer, and this portion also serves as a cushion. Reference numeral 13 denotes a base paper made of PET (polyethylene terephthalate) or YUPO. In FIG. 14B,
14 is a hole as viewed from the surface.

As another method, ink absorption can be realized by providing a melt absorbing layer having a temperature lower than the melting point of the ink on the surface of the recording paper. FIG. 15 is a sectional view of the recording paper of this method.
Shown in FIG. 15 (a) shows a case where only a melt-absorbing layer is provided, and FIG. 15 (b) is a cross-sectional view when a cushion layer is further provided. In FIG. 15, 13 is a base paper, 1
Reference numeral 5 denotes a melt-absorbing layer for absorbing ink, and 17 denotes a cushion layer.

Embodiment 5 FIG. Next, another invention will be described. The present invention relates to a thermal recording apparatus for transferring an ink-absorbing substance to a recording paper having no ink-absorbing structure and then transferring the ink.

FIG. 16 shows an example of an ink sheet coated with an ink absorbing layer. In FIG. 16, reference numeral 18 denotes an area to which an ink absorbing layer is applied, 19 denotes an area to which yellow ink is applied, 20 denotes an area to which magenta ink is applied, 21
Is an area to which cyan ink is applied, 22 and 23 are ink absorption layer discrimination marks, and 24, 25 and 26 are marks for discriminating yellow, magenta and cyan inks, respectively. Here, three color ink sheets are shown,
The mark may be monochrome, and the mark may be located at any position on the ink sheet as long as each mark can be identified.

FIG. 17 is a block diagram of a thermal recording apparatus when the ink sheet of FIG. 16 is used. In FIG. 17, 1 is a thermal head, 2 is a recording paper, 3 is an ink sheet, 4 is a platen roller, 6 is a memory, 7 is a gradation conversion section, and 27 is a mark for discriminating the ink absorbing layer discriminating marks 22 and 23. A sensor 28 for determining the ink determination marks 24 to 26; 29 a data generator for transmitting data to the thermal head 1 when transferring the ink absorbing layer 18;
0 is a sensor 2 for switching between sending image data to the thermal head 1 and sending transfer data for the ink absorbing layer 18.
This is a data switching unit that performs discrimination based on states 7 and 28.

Next, the operation will be described with reference to FIGS. The ink absorbing layer discrimination mark 2 by the sensor 27
2 and 23 are detected, and it is determined that the ink absorbing layer 18 is formed. Next, switching is performed by the data switching unit 30 so as to send the ink absorption layer transfer data of the data generation unit 29 to the thermal head 1, and the ink absorption layer transfer data is sent to the gradation conversion unit 7. The thermal head 1 generates heat according to this data, and the ink absorbing layer 18 is transferred from the ink sheet 3 to the recording paper 2. After the transfer of the ink absorbing layer 18, the data is switched by the data switching unit 30 so as to send the image data stored in the memory 6, and the recording of the ink is normally performed.

In the present invention, an ink absorbing substance transfer device different from the thermal head may be used.

Embodiment 6 FIG. Next, another invention will be described. It has been proposed to provide an ink absorbing layer between the ink sheet and the ink layer in order to suppress image disturbance on the high gradation side. FIG. 18 is a sectional view of an ink sheet according to the present invention.
FIG. 19 shows a transfer state when the ink is transferred. In FIG. 18, 31 is a base film, 32 is an ink absorbing layer, and 33 is an ink layer. In FIG. 19, 2 is a recording paper, 33a is a transferred ink, and 32a is a transferred ink absorbing layer. Here, the transferred ink 33
When transfer is performed on a, the ink 33a is absorbed by the ink absorption layer 32a, and a smooth gradation can be reproduced. Further, at this time, the melting point of the ink absorbing layer 32a is set to be equal to or lower than the melting point of the ink 33a.

Embodiment 7 FIG. Next, another invention will be described. This invention compares a signal for designating a sublimation type recording mode or a fusion type recording mode with a mounted recording medium in a thermal recording apparatus in which a plurality of types of ink sheets and recording papers can be mounted. Starts the recording operation, and in the case of inconsistency, displays that fact on the display means or warns with the warning sound generation means and does not start the recording operation, thereby improving the operability for the user. I do.

FIG. 20 shows a configuration diagram of a thermal recording apparatus according to the present invention. In FIG. 20, reference numeral 46 denotes a recording paper sensor,
Reference numeral 7 denotes an ink sheet sensor, and any number of them may be provided according to the type of recording medium. A determination unit 48 determines whether the recording medium and the recording method match. 5
Reference numeral 0 denotes a display means such as an LCD or an LED. In addition, 1
11 are the same as those in the first embodiment shown in FIG.

Next, the operation will be described with reference to FIG. First, a recording method desired by the user is set by the recording method selection signal generating means 8. The settings and sensors 46 and 47
The recording unit selection signal is input to the color conversion unit 5, the power supply control unit 9, and the paper conveyance motor control unit 10 to start recording. Show errors. Instead of displaying on the display means 50, a sound, a warning sound, music or the like may be sounded. Also, the types of the recording paper and the ink sheet are determined by the sensors 46 and 47, and the determination unit 4
If the recording system selection signal is generated in step 8, the recording system selection signal generating means 8 is unnecessary.

Embodiment 8 FIG. Next, another invention will be described. When the recording paper has high smoothness, the recording sensitivity is apparently higher than when the recording paper has low smoothness. Therefore, it is necessary to change the recording energy depending on the smoothness of the recording paper. The present invention provides a thermal recording apparatus in which a plurality of types of recording paper can be mounted, and has a means for identifying the type of recording paper by optical reflection or transmitted light from the recording paper, so that the recording paper having different smoothness is always provided. It is possible to perform recording with optimum energy, reduce the number of sensors for determining when there are many types of recording paper, and eliminate the need for marks on recording paper. The smoothness of the recording paper can be detected by detecting the scattering component of the reflected light with an optical sensor and determining the magnitude thereof. OHP paper can be identified by the magnitude of the transmitted light component.

FIG. 21 is a block diagram of a thermal recording apparatus according to the present invention. In the figure, reference numeral 52 denotes a light-emitting element for generating reflected light and transmitted light, which may generate infrared light or visible light. 53 is a light receiving element for viewing the reflected light. Since the amount of scattered light varies depending on the smoothness of the recording paper, the change is sensed by the light receiving element 53, and the recording paper is determined.
Recording energy can be optimally applied. Also, 54
Is a light receiving element for viewing transmitted light, and the transmitted light is used for determining OHP. The light emitting element 52 and the light receiving element 5
Reference numerals 3 and 54 are arranged near the paper feed port. Reference numeral 55 denotes a medium discrimination unit that discriminates a recording sheet. Note that 1 to 11
Is similar to that of the first embodiment shown in FIG.

Next, the operation will be described with reference to FIG. First, the light emitting element 52 is turned on. Next, the light receiving elements 53, 5
4 is received by the medium discriminating section 55, and the smoothness or type of the recording paper 2 is determined based on the data, or the OHP is determined.
The sheet is determined. This information is passed to the power supply controller 9.
Next, the image data is color-converted by the color conversion unit 5 and fetched into the memory 6, subjected to binary conversion by the gradation conversion unit 7, and then output to the thermal head 1. In response to the data, the power supply control unit 9 outputs an optimum power supply pulse to the thermal head 1 for the currently loaded recording paper 2 so that ink is transferred from the ink sheet 3 to the recording paper 2. Here, the amount of the energizing pulse of the energizing control unit 9 is changed to change the recording energy, but the recording energy may be changed by using a means for increasing or decreasing the value of the image input data.

Although only one light emitting element 52 is provided here, two light emitting elements 52 may be provided for reflected light and for transmitted light. Also, instead of providing the light receiving element 54, there is also a configuration in which a mark for generating reflected light is provided on the OHP, and all the media are determined only by the reflected light.

Further, if the type of the recording paper 2 is determined by the medium determining unit 55 and a recording system selection signal is generated by the medium determining unit 55 based on the determination result, the recording system selection signal generating means 8 becomes unnecessary. is there. The optimization of the recording conditions by discriminating the recording paper is an indispensable technique not only when the heating means is a thermal head, but also when a laser beam, energized heat generation, or a discharge infrared thermal transfer method is adopted.

Embodiment 9 FIG. Next, another invention will be described. The present invention relates to a thermal recording apparatus capable of performing halftone printing of n gradations (n is an integer of 2 or more). This enables recording of n gradations or less.

FIG. 22 shows a configuration diagram of a thermal recording apparatus according to the present invention. In FIG. 22, reference numeral 43 denotes a gray scale number setting means for generating a signal for determining the number of gray levels to be assigned to the n gray scales, which is set by a button or switch of the main body or an external input such as a host computer. It is a means to do.
The signal from the number-of-gradations setting means 43 may be a signal that can specify the number of gradations to be assigned to one. For example, when recording on a certain recording paper, it is determined in advance such that 64 gradations are recorded. The key number may be determined.

Reference numeral 44 denotes a gradation assigning unit, which is a gradation number setting means 43.
Is assigned according to the signal of (1). In this case, the number of gradations is not necessarily assigned to 1 and 0, even if the assignment is made to two gradations when n = 256.
Alternatively, it may be assigned to two gradations such as 255 and 0, and it is sufficient if the result is two gradations. The same applies to other gradation numbers. 1 to 11 are the same as those in the first embodiment shown in FIG.

Next, the operation will be described with reference to FIG. First, the recording method signal generation means 8 generates a recording method selection signal indicating whether the recording method is the fusion recording method or the sublimation recording method, according to the user's selection. This selection signal is input to the color converter 5, the power supply controller 9, and the paper transport motor controller 10. After that, the image data is input, color conversion is performed by the color conversion unit 5 according to the recording method selection signal, and the data is stored in the memory 6. Next, the number of assigned gradations is determined by the number-of-gradation setting unit 43, the gradation is assigned by the gradation assigning unit 44 according to the signal of the number-of-gradation setting unit 43, and the data is transmitted to the gradation conversion unit 7. Can be Next, data is transferred from the gradation converter 7 to the thermal head 1, a strobe is output from the power supply controller 9 to the thermal head 1, and ink is transferred from the ink sheet 3 to the recording paper 2. Note that the positions of the tone allocating unit 44 and the memory 6 may be reversed.

Embodiment 10 FIG. Next, another invention will be described. The present invention relates to a thermal recording apparatus capable of performing halftone printing of n gradations (n is an integer of 2 or more). When printing is performed with n gradations or less, the recording cycle can be shortened by driving the thermal head the maximum number of times of allocation of n gradations or less.

FIG. 23 is a block diagram of a circuit in the thermal head. The figure shows a case in which there are four data inputs, one strobe, and each IC for 128 dots. In this case, the data is DATA1, DATA2, DATA3,
The data is input from each signal line of DATA4 while being shifted in the IC one dot at a time in accordance with the clock signal. When the data input is completed, a latch signal is input next, and the input data is latched. Thereafter, a strobe signal is input, a current flows through the heating resistor according to the strobe and the latched data, and the heating resistor generates heat. This operation is repeated (n-1) times in the case of n gradations, so that recording of one line is performed.

Here, when n = 256, the data transfer time is given by the transfer time of one data × the number of dots of one driver IC × the number of gradations when the transfer clock is 8 MHz. Therefore, 125 ns × 128 × 256 = 4. 096
ms, and the sum of the current supply time of 1 ms is the recording cycle of one line. Therefore, the recording cycle in this case is about 5 m
s.

The data transfer time when the number of allocated gradations is 64 is similarly calculated as follows: 125 ns × 128 × 64 = 1.024
ms Further, the energizing time is added, and the recording cycle becomes about 2 ms.
It is possible to perform recording with a cycle that is less than half that of gradation recording. Therefore, in a thermal recording apparatus capable of halftone recording of n gradations,
When the assignment to any one of the n gradations is performed, the recording cycle can be significantly reduced by driving the thermal head several times the maximum assigned gradations of n gradations or less.

The construction of the thermal recording apparatus according to the present invention is the same as that of the ninth embodiment shown in FIG. However, the gradation conversion unit 7 shown in FIG. 22 outputs data to the thermal head 1 only several times for recording gradations.

Next, the operation will be described with reference to FIG. First, the recording method signal generation means 8 generates a recording method selection signal indicating whether the recording method is the fusion recording method or the sublimation recording method, according to the user's selection. This selection signal is input to the color converter 5, the power supply controller 9, and the paper transport motor controller 10. After that, the image data is input, color conversion is performed by the color conversion unit 5 according to the recording method selection signal, and the data is stored in the memory 6. Next, the number of recording gradations is determined by the gradation number setting means 43 and output to the gradation allocating section 44. Next, a tone is assigned by the tone assigning section 44 and output to the tone converting section 7. Then, data is output to the thermal head 1 only for the number of recording gradations, and then a strobe corresponding to the number of recording gradations is output from the conduction control unit 9 to the thermal head 1. At the same time, the paper transport motor 11 is driven by the paper transport motor controller 10 at a speed corresponding to the number of recording gradations, and the ink sheet 3
Is transferred to the recording paper 2 from.

In this case, the number-of-gradations setting means 43 and the gradation allocating section 44 are provided in the thermal recording apparatus, but the number-of-gradations setting means 43 and the gradation allocating section 44 are provided in a host computer (not shown). Is also good.

Embodiment 11 FIG. Next, another invention will be described. According to the present invention, in a thermal recording apparatus in which a plurality of types of ink sheets and recording paper can be mounted, the paper feed amount for one line is changed by changing the paper feed amount of one line according to the paper thickness of the recording paper. Correction enables recording without image quality deterioration.

FIG. 24 shows a configuration diagram of a thermal recording apparatus according to the present invention. In the figure, reference numeral 4 denotes a platen roller, and 64 denotes a medium information providing means for providing paper thickness information of a recording paper to a motor control unit for controlling the rotation of a motor 65. The medium information providing means 64 is a means for setting by a button or a switch of the main body or an external input from a host computer or the like. 66 is a motor drive unit for driving a motor, and 11 is a paper transport motor.

Next, the operation will be described with reference to FIG. First, the medium information providing unit 64 receives the sheet thickness information of the recording sheet and transmits the sheet thickness information to the motor control unit 65. Next, the motor driving unit 66 is driven at the time of recording according to the paper thickness information to drive the paper transport motor 11. Then the platen roller 4
Transports the paper.

Embodiment 12 FIG. Next, another invention will be described. The present invention provides an excellent user interface by having means for automatically enlarging and reducing input data to a maximum print size that can be recorded, or performing both enlargement and reduction.

The enlargement according to the present invention is always performed with the same ratio between the vertical and horizontal magnifications. That is, for example, if the input image is 100 dots × 100 dots when the maximum print size is 1800 dots × 2,500 dots,
An image of 1800 dots × 1800 dots is printed by enlarging and changing the magnification by 8 times, and the image is not deformed. If the input image is 3600 dots × 3000 dots, 180
Reduction and magnification of 0.5 times vertically and horizontally, such as 0 dots × 1500 dots, are performed.

FIG. 25 shows a configuration diagram of a thermal recording apparatus according to the present invention. In the figure, reference numeral 67 denotes a maximum printing mode selection means for selecting whether to use or not use the maximum printing mode, which is set by an external input such as a button or switch of the main body or a host computer. Reference numeral 68 denotes a scaling ratio calculator which calculates a scaling ratio from the image size data of the image and the pixel size data of the maximum print size of the main body. 69
Is a scaling unit, which actually scales the image data based on the calculation result of the scaling unit 68. 1 to 11 are the same as those in the first embodiment shown in FIG.

Next, the operation will be described with reference to FIG. First, the maximum printing mode is selected by the maximum printing mode selecting means 67. Next, the maximum print size data and the pixel size data of the input image data are input. Next, the scaling factor is calculated by the scaling factor calculator 68 and passed to the scaling unit 69. Next, the image data transferred to the memory 6 is scaled by the scaling unit 69 and transferred to the gradation conversion unit 7 for recording.

When the size of the recording paper is one type,
If the maximum print size data is stored in advance in the variable magnification calculator 68, the input of the maximum print size data is not required. Further, the positions of the magnification unit 69 and the memory 6 may be reversed. In particular, in the case where a reduction function is provided, the memory capacity can be reduced by reversing the function.

Embodiment 13 FIG. Next, in a thermal recording apparatus in which a plurality of types of ink sheets can be mounted, the paper pressing spring strength is changed according to the thickness of the recording paper, thereby making it possible to feed paper such as paper jams and double feeds. This makes it possible to prevent defects.

FIG. 26 shows a configuration diagram of a thermal recording apparatus according to the present invention. 26A and 26B are side views of the paper cassette, and FIG. 26C is a front view of the paper cassette. FIG.
5A, reference numeral 59 denotes an outer frame of a paper cassette, and reference numeral 60 denotes a plate for pushing up paper, one of which is movable. 6
Reference numeral 1 denotes a spring for pushing up the plate 60, and 62 denotes a plate spring for supporting the spring below. FIG. 26B shows a state in which the projection 63 is locked to the plate 60. The locking force of the projection 63 reduces the pressing force of the spring 61 and consequently changes the pressing force of the paper. Can be.

[0124]

According to the first aspect of the present invention, there is provided an energization control section for controlling electric power applied to the heating resistor of the thermal head in accordance with a signal from a setting section for setting the melting mode and the sublimation mode. The horizontal length of the heating resistor was 0.35 to 0.75 with respect to the pitch interval of the heating resistor, and the vertical length was 1.5 to 2.5 times the horizontal length. Thereby, in both the fusion type recording method and the sublimation type recording method, when performing halftone recording, blurring at the time of low gradation is eliminated, and dot breakage and stability are improved.

According to the second aspect of the present invention, the interval between the unit pulses of at least two energization control signals is set to 10 units.
By leaving 0 to 500 ns, polymerization of the energization control signals can be eased, and a high-quality image without density unevenness can be obtained.

According to the third aspect of the present invention, a high-quality image without density unevenness can be obtained by controlling the control of at least two energization control signals by a mixed control of the pulse number control and the pulse width control.

According to the fourth, fifth and sixth aspects of the present invention, when a halftone recording is performed in a thermal recording apparatus using a melting type ink sheet, a high quality image without unevenness generated on the high gradation side can be obtained. can get.

According to the seventh and eighth aspects of the present invention, the operability of the user is remarkably improved in a thermal recording apparatus in which a plurality of types of ink sheets and recording paper can be mounted.

According to the ninth aspect of the present invention, in a thermal recording apparatus in which a plurality of types of ink sheets and recording paper can be mounted, the number of gradation setting means and the gradation allocating section are provided, so that the running cost is lower than the sublimation type. However, it is possible to perform test printing with a cheap melt-type system.

According to the tenth aspect, by changing the paper feed amount of one line according to the paper thickness, it is possible to perform recording without image quality deterioration.

According to the eleventh aspect of the present invention, by providing the maximum printing mode, it is possible to obtain an image on which maximum printing has been performed by a simple operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a thermal recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an energy density characteristic with respect to a lateral length of a heating resistor.

FIG. 3 is an explanatory diagram illustrating a heat distribution of a heating resistor.

FIG. 4 is a characteristic diagram illustrating an energy density characteristic with respect to a lateral length of a heating resistor.

FIG. 5 is an explanatory diagram illustrating a place where a heating resistor generates heat.

FIG. 6 is an explanatory diagram for explaining dot growth when the longitudinal length of the heating resistor is changed.

FIG. 7 is a characteristic diagram showing an energy density characteristic with respect to a vertical length of a heating resistor.

FIG. 8 is a configuration diagram of an energization control unit of a thermal recording apparatus according to Embodiment 2 of the present invention.

FIG. 9 is a waveform diagram of a strobe signal for explaining an energization control unit of the thermal recording apparatus according to the second embodiment of the present invention.

FIG. 10 is a characteristic diagram of recording density for explaining an energization control unit of a thermal recording apparatus according to Embodiment 2 of the present invention.

FIG. 11 is a configuration diagram of an energization control unit of a thermal recording apparatus according to Embodiment 3 of the present invention.

FIG. 12 is a waveform diagram of a strobe signal generated by an energization control unit of the thermal recording apparatus according to the third embodiment of the present invention.

FIG. 13 is a characteristic diagram illustrating energy density characteristics when the amount of ink applied is changed.

FIG. 14 is a cross-sectional view illustrating a structure of a recording sheet according to a fourth embodiment of the present invention.

FIG. 15 is a cross-sectional view illustrating a structure of a recording sheet according to a fourth embodiment of the present invention.

FIG. 16 is a configuration diagram illustrating a structure of an ink sheet according to a fifth embodiment of the present invention.

FIG. 17 is a configuration diagram of a thermal recording apparatus according to Embodiment 5 of the present invention.

FIG. 18 is a sectional view of an ink sheet according to Embodiment 6 of the present invention.

FIG. 19 is an explanatory diagram illustrating a state when ink is transferred to paper according to Embodiment 6 of the present invention.

FIG. 20 is a configuration diagram of a thermal recording apparatus according to Embodiment 7 of the present invention.

FIG. 21 is a configuration diagram of a thermal recording apparatus according to Embodiment 8 of the present invention.

FIG. 22 is a configuration diagram of a thermal recording apparatus according to Embodiment 9 of the present invention.

FIG. 23 is a configuration diagram of a circuit inside a thermal head of a thermal recording apparatus according to Embodiment 10 of the present invention.

FIG. 24 is a configuration diagram of a thermal recording apparatus according to Embodiment 11 of the present invention.

FIG. 25 is a configuration diagram of a thermal recording apparatus according to Embodiment 12 of the present invention.

FIG. 26 is a configuration diagram of a paper cassette according to Embodiment 13 of the present invention.

FIG. 27 is a waveform diagram of an energizing pulse applied to a conventional heating resistor.

FIG. 28 is a waveform diagram of a conventional strobe signal.

FIG. 29 is a basic configuration diagram of a conventional thermal transfer recording apparatus.

FIG. 30 is a configuration diagram of an ink sheet of a conventional printer for both melting and sublimation.

FIG. 31 is a configuration diagram of a conventional melting / sublimation printer.

FIG. 32 is an explanatory diagram for explaining an energizing time of a conventional melting / sublimation printer.

FIG. 33 is an explanatory diagram for explaining an energizing time and a line feed time of a conventional melting / sublimation printer.

FIG. 34 is an explanatory diagram illustrating a change of one dot in the sublimation recording method.

FIG. 35 is an explanatory diagram for explaining a change of one dot in the fusion recording method.

FIG. 36 is an explanatory diagram illustrating density unevenness according to a driving method of a thermal head.

FIG. 37 is an explanatory diagram illustrating a current behavior result when the thermal head is driven.

FIG. 38 is a waveform diagram of a strobe signal when performing pulse width control.

FIG. 39 is a waveform diagram of a strobe signal when performing pulse number control.

FIG. 40 is an explanatory diagram for explaining a change in dots in a fusion recording method.

FIG. 41 is an explanatory diagram for explaining dot unevenness in the fusion recording method.

FIG. 42 is an explanatory diagram illustrating a difference in paper feed amount due to a difference in paper thickness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal head 1a Heating resistor 2 Recording paper 3 Ink sheet 4 Platen roller 5 Color conversion unit 6 Memory 7 Gradation conversion unit 8 Recording method selection signal generation means 9 Power supply control unit 10 Paper transport motor control unit 11 Paper transport motor 12 Ink Absorption layer 13 Base paper 14 Ink absorption hole 15 Melt absorption layer 17 Cushion layer 18 Ink absorption layer application surface 19 Yellow ink application surface 20 Magenta ink application surface 21 Cyan ink application surface 22, 23 Ink absorption layer discrimination mark 24, 25, 26 Ink discrimination mark 27, 28 Sensor 29 Data generation unit 30 Data switching unit 31 Base film 32 Ink absorption layer 33 Ink layer 35, 36, 37, 38 Counter 39 Pulse number generation unit 40 Pulse number control unit 41 Pulse width setting unit 42 Pulse Several pulse width control unit 43 gradation Setting means 44 gradation assigning sections 46, 47 sensors 48 determining section 50 display means 52 light emitting elements 53, 54 light receiving elements 55 medium discriminating section 64 medium information providing means 65 motor controlling section 66 motor driving section 67 maximum printing mode selecting means 68 Magnification calculator 69 Zoom unit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takayoshi Yamada 5-1-1, Ofuna Kamakura City Mitsubishi Electric Corporation Personal Information Equipment Development Laboratory (56) References JP-A-1-157870 (JP, A) JP-A-60-977 (JP, A) JP-A-60-110492 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/325 B41J 2/345 B41J 2 / 36

Claims (11)

(57) [Claims] 1. A thermal head in which a plurality of heating resistors are arranged in a horizontal direction, and ink applied to a melting type or sublimation type ink sheet is transferred to recording paper by heat of the heating resistors. In the thermal recording apparatus, a setting unit for setting a melting type mode and a sublimation type mode, and an energization control unit for controlling electric power applied to a heating resistor of the thermal head according to a signal from the setting unit are provided. The body has a lateral length of 0.35 with respect to the pitch interval of the heating resistors.
0.75, and the vertical length is 1.5 times the horizontal length.
A thermal recording device characterized by up to 2.5 times. 2. A plurality of heating resistors are divided into a plurality of groups in a horizontal direction, and energization control signal lines of the number of divided groups are provided, and the energization control unit supplies power to the heating resistors by the energization control signal lines. 2. The thermal recording apparatus according to claim 1, wherein the heating is performed by sequentially applying pulses as in (1), and an interval between the pulses for each of the energization control signal lines is set to 100 to 500 ns. 3. The thermal recording apparatus according to claim 2, wherein the pulse number control and the pulse width control are performed in combination with an energization control signal by an energization control signal line. 4. A thermal recording apparatus according to claim 1, further comprising: a melting type ink sheet coated with an ink of 2.5 g / m ² or less, and a recording paper provided with an ink absorbing layer on the surface. apparatus. 5. A melting type ink sheet in which a surface coated with an ink of 2.5 g / m ² or less and a surface coated with an ink absorbing material are formed, and the ink absorption before transferring the ink to recording paper. 2. A thermal recording apparatus according to claim 1, further comprising means for generating data for transferring a substance to recording paper. 6. The thermal recording apparatus according to claim 1, wherein the ink layer of the ink sheet for a melting type is provided with an ink absorbing layer for absorbing the ink to which the previously transferred ink is transferred next. . 7. A comparison is made between the signal of the setting section for setting the fusion type mode and the sublimation type mode and the attached recording medium, and when the two coincide, the recording operation is started. 2. The thermal recording apparatus according to claim 1, further comprising means for warning the user that the recording operation has stopped. 8. The thermal recording apparatus according to claim 1, further comprising means for identifying the type of recording paper based on its optical characteristics, and means for changing recording energy according to the identification result of the identification means. 9. An image processing apparatus comprising halftone means capable of n-gradation recording (n is an integer of 2 or more). 2. The thermal recording apparatus according to claim 1, further comprising an assigning unit. 10. The thermal recording apparatus according to claim 1, further comprising means for changing a paper feed amount of one line according to the thickness of the recording paper. 11. The thermal recording apparatus according to claim 1, further comprising means for automatically enlarging, reducing, or both enlarging and reducing the input data to a maximum print size capable of recording.