JPH09272218A - Thermal recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the decline of the sharpness of a recorded image by moving a thermal head and a thermal recording material relatively in the direction orthogonal to the direction heating elements are arranged with glaze and the thermal recording material contacted with each other so as to alter the sharpness correction coefficient according to the temperature of the thermal head. SOLUTION: A thermal material A is conveyed to a recording portion 20 by a supply conveyance portion in a recording apparatus so that a thermal image recording is conducted by conveying the thermal material A with a thermal head 66 pressed thereon in the direction orthogonal to the extending direction of the glaze, and heating each of heating elements according to an image to be recorded. A thermistor is provided in the thermal head 66 for detecting and sending the temperature of the glaze 66a, to an image processing portion 80. According to the temperature, not only the temperature but also the correction coefficient of the sharpness is corrected. Accordingly, an high quality thermally recorded image can be formed stably having a good sharpness without the image obstruction regardless of the temperature of the thermal head 66.

Description

Detailed Description of the Invention

[0001]

The present invention belongs to the technical field of a thermal recording apparatus using a thermal head.

[0002]

2. Description of the Related Art An image recording using a heat-sensitive recording material (hereinafter, referred to as a heat-sensitive material) in which a heat-sensitive recording layer is formed using a film or the like as a support for recording an ultrasonic diagnostic image (hereinafter referred to as a heat-sensitive image recording). Is used. In addition, thermal image recording has advantages such as no necessity of wet development processing and easy handling. In recent years, not only small-sized image recording such as ultrasonic diagnosis but also CT diagnosis,
For applications requiring large and high-quality images, such as RI diagnosis and X-ray diagnosis, use for image recording for medical diagnosis is also being studied.

As is well known, thermal image recording uses a thermal head having a glaze in which heating elements are arranged in one direction to record an image by heating a thermosensitive recording layer of the thermosensitive material. While slightly pressing the (thermosensitive recording layer), press the both in the glaze extending direction (main scanning direction).
While relatively moving in the direction (sub-scanning direction) orthogonal to
By applying energy to each heating element of the glaze and heating according to the recorded image, the heat-sensitive recording layer of the heat-sensitive material is heated to perform image recording.

[0004]

By the way, in order to obtain not only such thermal recording but also various image recording apparatuses such as laser printers and printing plate making apparatuses, in order to obtain clear images with high image quality and clarity, Sharpness correction (sharpness processing) is performed to enhance the sharpness of the image by emphasizing the contour of the recorded image. However, the sharpness of the recorded image is affected by various factors, and in thermal recording, factors that reduce the image sharpness include the temperature of the thermal head, the recording speed (sub-scanning conveyance speed), and the γ value of the heat-sensitive material. Is mentioned. Specifically, in thermal recording, the higher the temperature of the thermal head (heating element), the faster the recording speed (the relative movement speed between the thermal head and the thermal material), and the lower the γ value of the thermal material, There is a problem that the sharpness of the recorded image is lowered and the image looks blurred. More specifically, with respect to the printing speed, the sharpness of the printed image decreases in the sub-scanning direction as the printing speed becomes faster, and in the main scanning direction as the printing speed becomes slower.
There is a problem that the image looks out of focus. Among these, the increase in the temperature of the thermal head has a great influence on the decrease in the sharpness of the recorded image.

Such a reduction in the sharpness of the recorded image leads to a reduction in the quality of the finished image, which is a serious problem in applications where high quality image recording is required. In particular, for medical applications as described above, high-quality images are required, and the sharpness reduction becomes an obstacle to image observation, which is a serious problem leading to erroneous diagnosis.

An object of the present invention is to solve the above-mentioned problems of the prior art, and the sharpness of the recorded image is lowered due to the rise of the temperature of the thermal head, and more preferably, the recording speed is increased or the heat-sensitive material is used. To provide a thermal recording apparatus capable of suitably reducing a decrease in sharpness of a recorded image due to a decrease in γ value or both of them, and capable of stably outputting a high-quality image with sharpness. It is in.

[0007]

In order to achieve the above object, the present invention receives image data from an image supply source, performs image processing including sharpness correction on the image data, and obtains thermal recording image data. And a thermal head for recording an image on a heat-sensitive recording material by causing the heat-generating element to generate heat in accordance with the heat-sensitive recording image data. And a thermal recording material in contact with each other, means for relatively moving the thermal head and the thermal recording material in a direction orthogonal to the arrangement direction of the heating elements, and a temperature measuring means for the thermal head, Further, there is provided a thermal recording apparatus, wherein the image processing section has a sharpness correction coefficient changing means according to the temperature of the thermal head.

Further, the thermal recording apparatus of the present invention further comprises at least one of a recording speed detecting means, a γ value detecting means of the thermal recording material and a γ value setting means of the thermal recording material, and the image In addition to the temperature of the thermal head, the processing unit determines the recording speed and γ of the thermal recording material.
It is preferable to have a means for changing the sharpness correction coefficient in which at least one of the values is taken into consideration.

Further, the means for changing the sharpness correction coefficient is
It is preferable to separately change the sharpness correction coefficient in the arrangement direction of the heating elements and the sharpness correction coefficient in the relative movement direction of the thermosensitive recording material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The thermal recording apparatus of the present invention will be described in detail below with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic view of an example of the thermal recording apparatus of the present invention. A thermosensitive recording device 10 (hereinafter, referred to as a recording device 10) shown in FIG. 1 is a thermosensitive recording material (hereinafter, referred to as a cut sheet of a predetermined size such as B4 size).
A heat-sensitive image is recorded on the heat-sensitive material A),
A magazine 24 containing the heat-sensitive material A is loaded, a supply section 16, a recording section 20 for recording a heat-sensitive image on the heat-sensitive material A by the thermal head 66, and an ejecting section 22. . Further, as shown in FIG. 3, an image processing unit 80, an image memory 82 and a recording control unit 84 are connected to the thermal head 66 of the recording unit 20, and the image processing unit 80 further includes a correction data storage unit 86.
Is connected.

In the recording apparatus 10 as described above, the supply / conveyance unit 16 conveys the thermosensitive material A to the recording unit 20 and presses the thermal head 66 against the thermosensitive material A, as shown by an arrow c in FIG. (1) A direction orthogonal to a paper surface) A heat-sensitive material A is conveyed in a direction (also referred to as a sub-scanning direction) orthogonal to a glaze extending direction (also referred to as a main scanning direction) to heat each heating element according to a recorded image. Thus, the heat-sensitive image recording is performed on the heat-sensitive material A.

The heat-sensitive material A comprises a film such as a transparent polyethylene terephthalate (PET) film or paper as a support, and a heat-sensitive recording layer formed on one surface thereof. Such a heat-sensitive material A is usually formed into a laminated body (bundle) of a predetermined unit such as 100 sheets and packaged in a bag body or a band. In the illustrated example, the heat-sensitive recording layer is kept in a predetermined unit bundle. Is placed in the magazine 24 of the recording device 10 with the lower side as the lower surface, and is taken out one by one from the magazine 24 to be used for thermal image recording.

The magazine 24 is a casing having a lid 26 that can be opened and closed, and accommodates the thermosensitive material A and is loaded into the loading section 14 of the recording apparatus 10. The loading unit 14 includes the recording device 10
Insertion hole 30 formed in housing 28 of
And the guide rolls 34, 34, and the stop member 36, and the magazine 24 is inserted into the insertion port 30 with the lid 26 side first.
Is inserted into the recording device 10, is guided by the guide plate 32 and the guide roll 34, and is pushed to a position where it abuts on the stop member 36, so that the recording device 10 is loaded at a predetermined position.

The supply / conveyance means 16 takes out the thermosensitive material A from the magazine 24 loaded in the loading section 14 and conveys it to the recording section 20, and uses a sucker 40 for adsorbing the thermosensitive material A by suction. It has a mechanism, a conveyance means 42, a conveyance guide 44, and a regulation roller pair 52 located at the exit of the conveyance guide 44. The conveying means 42 includes a conveying roller 46, a pulley 47a coaxial with the conveying roller 46,
It has a pulley 47b and a tension pulley 47c connected to a rotary drive source, an endless belt 48 stretched over these three pulleys, and a nip roller 50 pressed by a transport roller 46. The heat-sensitive material A is conveyed by holding the tip of the leafed heat-sensitive material A between the conveyance roller 46 and the nip roller 50.

When an instruction to start recording is issued in the recording apparatus 10, the lid 26 is opened by an opening / closing mechanism (not shown), and the sheet-fed mechanism using the suction cup 40 takes out one sheet of the heat-sensitive material A from the magazine 24, and the heat-sensitive material is discharged. The leading end of A is supplied to the conveying means 42 (conveying roller 46 and nip roller 50). When the heat-sensitive material A is nipped by the conveyance roller 46 and the nip roller 50, the suction by the suction cup 40 is released, and the supplied heat-sensitive material A is guided by the conveyance guide 44 and regulated by the conveyance means 42 to the regulating roller pair 52.
Transported to When the heat-sensitive material A to be recorded is completely discharged from the magazine 24, the lid 26 is closed by the opening / closing means.

The distance defined by the transport guide 44 from the transport means 42 to the regulation roller pair 52 is set to be slightly shorter than the length of the heat-sensitive material A in the transport direction.
The leading end of the heat-sensitive material A reaches the regulating roller pair 52 by the conveyance by the conveying means 42, but the regulating roller pair 52 is initially stopped, and the leading end of the heat-sensitive material A is temporarily stopped and positioned here. At the time when the tip of the heat-sensitive material A reaches the regulating roller pair 52, the temperature of the thermal head 66 (glaze 66a) is confirmed. Is started, and the heat-sensitive material A is conveyed to the recording unit 20.

FIG. 2 shows a schematic diagram of the recording unit 20. The recording unit 20 includes a thermal head 66, a platen roller 60,
The cleaning roller pair 56, the guide 58, the cooling fan 76 (see FIG. 1) for cooling the thermal head 66, and the guide 62 are included. The thermal head 66 is, for example,
Approximately 300 dp capable of recording images up to B4 size
In order to perform the thermal image recording of the recording (pixel) density of i, the heating element for performing the thermal recording on the thermal material A is unidirectional,
That is, it has a thermal head body 66b formed with glazes 66a arranged in the main scanning direction (direction perpendicular to the paper surface in FIGS. 1 and 2 and arrow c direction), and a heat sink 66c fixed to the thermal head body 66b. .
The thermal head 66 is supported by a support member 68 that is rotatable about a fulcrum 68a in the direction of arrow a and in the opposite direction.

The platen roller 60 rotates at a predetermined image recording speed while holding the heat-sensitive material A at a predetermined position, and heats the heat-sensitive material A in the sub-scanning direction (direction of arrow b in FIG. 2) orthogonal to the main-scanning direction. Transport. The cleaning roller pair 56 includes an adhesive rubber roller 56a, which is an elastic body, and a normal roller 56.
b), and the adhesive rubber roller 56a removes dust and the like adhering to the heat-sensitive recording layer of the heat-sensitive material A,
This prevents dust from adhering to the glaze 66a and adversely affecting image recording.

In the recording apparatus 10 of the illustrated example, before the heat-sensitive material A is conveyed, the support member 68 is rotated upward (in the direction opposite to the arrow a direction), and the thermal head 66 (glaze 66a) is rotated. It is not in contact with the platen roller 60. When the transportation by the regulation roller pair 52 is started, the heat-sensitive material A is then nipped by the cleaning roller pair 56 and further transported while being guided by the guide 58. When the leading end of the heat-sensitive material A is transported to the recording start position (the position corresponding to the glaze 66a), the support member 68
Rotates in the direction of the arrow a, the heat sensitive material A is sandwiched between the glaze 66a of the thermal head 66 and the platen roller 60, and the glaze 66a is pressed against the recording layer. While being held at a predetermined position, the platen roller 60 (and the regulation roller pair 52 and the conveyance roller pair 63) conveys it in the sub-scanning direction indicated by arrow b.

Along with this conveyance, the heat-sensitive image recording is performed on the heat-sensitive material A by heating the heating elements of the glaze 66a according to the recorded image. Here, in the recording apparatus 10 of the present invention, this thermal image recording is performed by changing the correction coefficient of the sharpness correction according to the temperature of the thermal head 66 and the like as follows.

FIG. 3A shows a schematic perspective view of the thermal head 66, and FIG. 3B shows a block diagram of a recording control system of the thermal head 66. As shown in FIG. 3, the recording control system of the thermal head 66 basically includes the image processing unit 8
0, an image memory 82, and a recording controller 84. Further, the image processing unit 80 is connected to a correction data storage unit 86 that stores a weighting function or a weighting table of correction coefficients for sharpness correction.

Image (data) supply source R such as CT or MRI
The image data from is sent to the image processing unit 80. The image processing unit 80 is a combination of various image processing circuits and memories, receives image data from an image supply source R, and uses this image data for sharpness correction (sharpness correction) for enhancing the contour of the image. Processing); gradation correction for obtaining an appropriate image according to the γ value or the like of the heat sensitive material A; temperature correction for adjusting heat generation energy according to the temperature of the heat generating element; caused by shape variation of the glaze 66a of the thermal head 66, etc. Shading correction to correct density unevenness;
Resistance correction that corrects the difference in the resistance value of each heating element; Black ratio correction that colors the image data corresponding to the same density at the same density regardless of the change in the thermal head power supply voltage drop due to the change in the recording pattern; Image processing, and if necessary, format (enlarge / reduce,
(Frame allocation) is performed and image data is recorded in the image memory 8 as thermal recording image data corresponding to thermal recording by the thermal head 66.
Output to 2.

As shown in FIG. 3 (b), the fins of the heat sink 66c of the thermal head 66 of the illustrated example are provided with five notches 66d, 66d ... At the portion corresponding to the glaze 66a. The thermistor 88 is arranged at the base of the heat sink in this portion. Each thermistor 88 detects the temperature of the glaze 66a by measuring the temperature of the base portion of the heat sink 66c. In the illustrated example, the temperature of the glaze 66a (that is, the temperature of the heating element in this portion) is five places. ) Is detected.

The result of temperature detection by the thermistor 88 is sent to the image processing unit 80, which detects the temperature of each heating element by, for example, linear interpolation and performs the above-mentioned temperature correction according to the temperature. To do. Here, in the recording apparatus 10 according to the present invention, not only the temperature correction but also the (sharpness) correction coefficient of the sharpness correction is calculated by the glaze 66a.
It is corrected according to the temperature measurement result of the (heating element). Further, in the recording apparatus 10, as a preferable mode, the image processing unit 80 is supplied with the recording speed, that is, the conveying speed by the platen roller 60 and the signal S of the γ value data of the heat-sensitive material A, as necessary. In addition to the temperature of the glaze 66a, the section 80 also corrects the correction coefficient for sharpness correction by taking into account the recording speed and / or the γ value of the heat-sensitive material A, if necessary, and preferably, according to the recording speed. Then, the sharpness correction coefficient in the main scanning direction and / or the sub-scanning direction is corrected, and the sharpness is corrected using these. Here, in the thermal head recording method of the apparatus of the present invention, since the decrease in sharpness differs between the main scanning direction and the sub-scanning direction, the temperature of the glaze 66a and the γ value of the heat-sensitive material A are not limited to the recording speed. It is preferable that corrections are made in the main and sub-scanning directions with different correction coefficients.

Various known methods can be used for the sharpness correction, but as an example, it is performed as follows.
The image signal is divided into n × n pixels, and the j-th image signal in the extending direction of the glaze 66a in a certain pixel line i is represented by S _ij (i = 1, 2 ... n, j = 1, 2 ... n)
Then, in the sharpness correction, the image signal S
_ij is first converted into a ^first unsharpness signal U ¹ _ij which is an electrically blurred image signal. The first unsharpness signal U ¹ _ij is obtained by averaging the image signal S _ij and the image signals around it.

[Equation 1] Is required. Note that M is the number of pixels used for creating the ^first unsharpness signal U ¹ _ij , that is, the mask size, and L is defined by (M−1) / 2.

Then, the first unsharpness signal U ¹ _ij
Are further averaged to obtain a second unsharpness signal U ² _ij
Is calculated. The second unsharpness signal U ² _ij is
Like the unsharpness signal U ¹ _ij , it is calculated by the following equation (2).

[Equation 2]

Then, the first unsharpness signal U ¹ _ij
And the second unsharpness signal U ² _ij . Then, this difference is multiplied by the sharpness correction coefficient K and the first unsharpness signal U ¹ _ij is added, that is, the sharpness-corrected image signal S is obtained by the following equation (3).
_ij is obtained. S _ij = U ¹ _ij + K · (U ¹ _ij −U ² _ij ) (3)

Here, as described above, in the thermal recording, the sharpness of the image is determined by the thermal head 66 (heating element).
Of the thermal head 66, the higher the recording speed, the faster the recording speed,
Furthermore, the lower the γ value of the heat sensitive material A, the lower the sharpness of the recorded image. On the other hand, in the present invention, the sharpness correction coefficient K is changed according to the temperature of the heating element obtained from the temperature detection result by the thermistor 88 described above to perform the sharpness correction. In the preferred embodiment 10, in addition to the temperature of the heating element, the recording speed, the γ value of the heat-sensitive material A, or both are also taken into consideration, more preferably, the main scanning direction or the sub-scanning direction depending on the recording speed, or The sharpness correction is performed by changing the sharpness correction coefficient K in consideration of the influence on the sharpness correction in both directions.

As described above, the image processing unit 80 is connected to the correction data storage unit 86 that stores the weighting function or the weighting table of the sharpness correction coefficient K for sharpness correction. In the correction data storage unit 86, as shown in FIG. 4A, a weighting function (or a weighting function for calculating a weight α for obtaining the sharpness correction coefficient K corresponding to the temperature of the thermal head 66 (heating element)) (or 4B, a weighting function (table) for calculating the weight β ₁ for obtaining the sharpness correction coefficient K in the main scanning direction according to the recording speed, as shown in FIG. 4B. A weighting function (table) for calculating the weight β ₂ for obtaining the sharpness correction coefficient K in the sub-scanning direction according to the recording speed as shown in (c), and as shown in FIG. 4 (d). A weighting function (table) for calculating a weight δ for obtaining the sharpness correction coefficient K according to the γ value of the heat sensitive material A is stored.

At the time of sharpness correction, the image processing unit 80 uses the function (table) shown in FIG. 4A stored in the correction data storage unit 86 from the detected temperature of the heating element, The weight α is calculated (or read out), and the sharpness correction coefficient K is calculated (K = reference value × α) by multiplying the predetermined reference value of the sharpness correction coefficient K by the weight α. Sharpness correction is performed using the sharpness correction coefficient K.

Further, in the recording apparatus 10, the recording speed is basically constant, but in general, the lower the recording speed is, the higher the quality image can be obtained, and conversely, the higher the recording speed is. If so, quick image recording can be realized. Therefore, for example, if the recording apparatus has a high-speed mode for performing high-speed recording for the purpose of quick image recording and a high-quality mode for performing low-speed recording for the purpose of high image quality in addition to the normal recording speed, high-speed recording is possible. The sharpness of the image decreases as the temperature increases.
In this case, the correction data storage unit 8
As shown in FIGS. 4B and 4C in FIG. 6, different weighting functions (curves) in the main and sub-scanning directions, respectively.
May be stored in advance, and the filtering process may be performed by using different sharpness correction coefficients for the main and sub-scanning directions instead of the blur mask process. That is, the image processing unit 80 is stored in the correction data storage unit 86 as shown in FIG.
Using the functions of (a), (b) and (c), in addition to the weight α corresponding to the temperature, at least one of the weights β ₁ and β _{2 in} the main and sub-scanning directions corresponding to the recording speed is calculated. , The reference value of the sharpness correction coefficient K is separately multiplied by the weight α and the weights β ₁ and β ₂ to separately calculate the sharpness correction coefficient K in the main scanning direction and the sub-scanning direction (K =
(Reference value × α × β ₁ and reference value × α × β ₂ ), and the sharpness correction coefficient K is used to separately perform sharpness correction in the main scanning direction and the sub-scanning direction.

As an example of the sharpness correction performed by using the different sharpness correction coefficients in the main scanning direction and the sub-scanning direction thus obtained, the filter processing of the filter size 3 will be described. Here, when it is assumed that the sharpness correction coefficients for the main scanning direction and the sub scanning direction are K _m and K _s for the image data of the number of pixels M in the main scanning direction and the number of pixels N in the sub scanning direction, respectively. Considering the pixel (m, n) (m = 1 to M, n = 1 to N), assuming that the image data before correction is D _mn and the image data after correction is D ″ _mn , first in the main scanning direction. Performs sharpness correction as shown by the following equation. _{K -1 = -K m / 2,} K 0 = 1 + K m, K 1 = -K m / 2 D 'mn = K -1 × D mn-1 + K 0 × D mn + K 1 × D mn + 1 then In the sub-scanning direction, sharpness correction is performed as shown by the following equation. _{K -1 = -K s / 2,} K 0 = 1 + K s, K 1 = -K s / 2 D '' mn = K -1 × D 'm-1n + K 0 × D' mn + K 1 × D m + _{1n In} this way, sharpness correction can be performed with different intensities in the main scanning direction and the sub scanning direction.

The sharpness correction coefficient K according to the recording speed
It is preferable to adjust each of the weights β ₁ and β _{2 in} the main and sub-scanning directions separately, but it is also possible to adjust only one of them, whichever has a greater effect, It may be obtained in advance and only this weight may be used.

The γ value of the heat-sensitive material changes depending on the humidity and the installation environment, and the sharpness of the image decreases as the γ value decreases. Therefore, in the case of a device in which the γ value of the heat-sensitive material may fluctuate, the image processing unit 80 uses the function of FIGS. 4A and 4D stored in the correction data storage unit 86 to In addition to the weight α, the weight δ corresponding to the γ value of the heat-sensitive material is calculated, and the weight α is added to the reference value of the sharpness correction coefficient K.
And the weight δ are multiplied to calculate a sharpness correction coefficient K (K = reference value × α × δ), and this sharpness correction coefficient K is calculated.
Is used to correct the sharpness. Further, when both the recording speed and the γ value of the heat sensitive material fluctuate, the image processing unit 80
Calculates the sharpness correction coefficient K (different in the main scanning direction and the sub-scanning direction) by multiplying the reference value by all of the weights α, β ₁ or β ₂ and δ (K = reference value × α × β ₁ X δ and reference value x α x β ₂ x δ), and the sharpness correction coefficient K is used to perform sharpness correction.

Therefore, according to the recording apparatus 10 of the present invention,
There is no image blur regardless of the temperature of the thermal head 66, preferably the recording speed or the γ value of the heat-sensitive material A,
It is possible to stably create a high-quality heat-sensitive recorded image with good sharpness.

In the recording apparatus 10 of the present invention, the weight α,
The weighting function or table for obtaining β ₁ , β ₂ and δ may be appropriately determined according to the characteristics of the thermal head 66 used, the characteristics of the heat sensitive material A, the device configuration (heating, cooling efficiency, etc.), If the sharpness correction coefficient K exceeds the limit value, undershoot or overshoot occurs. Therefore, when the sharpness correction coefficient K exceeds the limit value, the sharpness correction is performed using this limit value. Alternatively, it is preferable to set the weighting function or table so that the limit value is not exceeded.

When the sharpness correction coefficient K is calculated by multiplying the weights β ₁ and β _{2 according} to the recording speed, the recording speed detection method is not particularly limited, and as described above, the image recording apparatus 1 is used.
If 0 has a mode such as high speed, normal, and high image quality recording, the image processing unit 8 is activated when the operator selects the mode.
The recording speed according to the mode may be set to 0, or the recording speed may be input by the operator, and the platen roller 6 may be detected by pulse detection or the like.
The transport speed of 0 may be detected. In addition, the heat-sensitive material A
When the sharpness correction coefficient K is calculated by multiplying the weight δ in accordance with the γ value of, the operator may input the γ value of the heat-sensitive material A, and the image processing unit 80 may perform tone correction. The γ value of the heat-sensitive material A may be calculated at the time of performing.

In this way, the image processing unit 80 performs sharpness correction, and further predetermined image processing such as gradation correction, temperature correction, shading correction, resistance correction, and black ratio correction. The thermal recording image data, which is formatted as necessary and is converted into image data corresponding to the thermal recording by the thermal head 66, is processed by the image processing unit 80.
And is stored in the image memory 82. The recording control unit 84 sequentially reads the thermal recording image data stored in the image memory 82 line by line in the extending direction of the glaze 66a, and outputs a recording signal (voltage application according to the image) according to the read thermal recording image data. The time width) is output to the thermal head 66. At each image recording point of the thermal head 66, heat is generated according to the recording signal, and as described above, the thermal image recording is performed while the heat sensitive material A is conveyed in the direction of the arrow b by the platen roller 60 or the like.

The heat-sensitive material A for which the heat-sensitive image recording has been completed is guided by the guide 62, is conveyed to the platen roller 60 and the pair of conveying rollers 63, and is ejected to the tray 72 of the ejecting section 22. The tray 72 protrudes outside the recording apparatus 10 through a discharge port 74 formed in the housing 28, and the heat-sensitive material A on which an image is recorded is discharged to the outside through the discharge port 74 and is taken out.

Although the thermal recording apparatus of the present invention has been described in detail above, the present invention is not limited to the above examples, and various improvements and changes may be made without departing from the gist of the present invention. Of course.

[0042]

As described above in detail, according to the thermal recording apparatus of the present invention, it is possible to reduce the decrease in the sharpness of the recorded image due to the increase in the temperature of the thermal head.
Mainly due to increase in recording speed and decrease in γ value of heat-sensitive material,
It is possible to suitably prevent the sharpness of the recorded image in the sub-scanning direction from being lowered, and it is possible to stably output a high-quality image without image blur.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an example of a thermal recording apparatus of the present invention.

FIG. 2 is a conceptual diagram of a recording unit of the thermal recording device shown in FIG.

FIG. 3A is a schematic perspective view of a thermal head,
(B) is a block diagram of a recording control system of the thermal head.

4 (a), (b), (c) and (d) are graphs showing a weighting function of a sharpness correction coefficient.

[Explanation of symbols]

 10 (Thermal Image) Recording Device 14 Loading Unit 16 Supplying Conveying Unit 20 Recording Unit 22 Ejecting Unit 24 Magazine 26 Lid 28 Housing 30 Insertion Port 32 Guide Plate 34 Guide Roll 36 Stopping Member 40 Sucker 42 Conveying Means 44 Conveying Guide 48 Endless Belt 50 Nip Roller 52 Control Roller Pair 56 Cleaning Roller Pair 58, 62 Guide 60 Platen Roller 63 Conveying Roller Pair 66 Thermal Head 68 Supporting Member 72 Tray 74 Ejection Port 76 Cooling Fan 80 Image Processing Section 82 Image Memory 84 Recording Control Section 86 Correction Data Storage Part 88 Thermistor A Thermosensitive (recording) material

Claims (3)

[Claims] 1. An image processing unit for receiving image data from an image supply source, subjecting the image data to image processing including sharpness correction, and converting the image data into thermal recording image data, and a heating element arranged in one direction. A thermal head that has a glaze and heats the heating element in accordance with the thermosensitive recording image data to record an image on the thermosensitive recording material, and in a state where the glaze and the thermosensitive recording material are in contact, It has a means for relatively moving the thermal head and the heat-sensitive recording material in a direction orthogonal to the arrangement direction, and a temperature measuring means for the thermal head, and the image processing section further comprises a sharpening device according to the temperature of the thermal head. A heat-sensitive recording apparatus having means for changing a degree correction coefficient. 2. The thermal recording apparatus according to claim 1,
Further, it has at least one of a recording speed detecting means, a γ value detecting means of the thermal recording material, and a γ value setting means of the thermal recording material, and the image processing unit is configured to add the recording speed And an image recording apparatus having a sharpness correction coefficient changing means that takes into account at least one of the γ values of the heat-sensitive recording material. 3. The sharpness correction coefficient changing means separately changes the sharpness correction coefficient in the arrangement direction of the heating elements and the sharpness correction coefficient in the relative movement direction of the heat-sensitive recording material. Alternatively, the heat-sensitive recording device described in 2.