JP2693962B2 - Recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a recording apparatus with improved recording quality.

(Prior Art) There is a thermal transfer recording apparatus as a recording apparatus that has good hard copy stability, low noise, and low cost. This thermal transfer recording apparatus uses an ink ribbon (ink film) for thermal transfer and a thermal head. The ink ribbon is interposed between the thermal head and the recording paper on the platen roller, and the thermal paper is pressed against the recording paper by the thermal head. While moving the ink ribbon and the thermal head at a predetermined speed in the direction orthogonal to the feeding direction of the ink, heat is generated by applying a heating current corresponding to a recording signal to a heating element of the thermal head. The recording device is configured to transfer the ink of the ink ribbon to the.
Such a thermal transfer recording apparatus has high running cost as compared with a thermal recording method using a thermal recording paper, but has good storability of hard copy obtained, and plain paper can be used as a recording paper. It is used in printers because it is excellent in.

Incidentally, in a facsimile receiving apparatus, a thermal recording apparatus or a thermal transfer recording apparatus is generally used. In this case, a line-type thermal head having a width corresponding to the recording paper width in which the heating elements are linearly arranged at a density of about 8 to 16 dots / mm is used, and the heating elements are arranged in the main scanning direction (horizontal direction). (Scanning direction), the paper feed direction is the sub-scanning direction (vertical scanning direction), the screen information for each line is main-scanned, and the next line is recorded by sub-scanning. go.

An outline of the thermal transfer recording device is shown in FIG. The principle of thermal transfer recording is that the thermal head shown by reference numeral 101 and the platen roller shown by reference numeral 104 sandwich the ink film having the width of the thermal head shown by reference numeral 102 and the recording paper shown by 105, and bring them into close contact with each other. By energizing the heating element of the head 101, heat energy is applied to melt the ink of the ink film 102 and attach it to the recording paper 105. In addition, 10
Reference numeral 3 is a guide shaft for guiding the ink film 102. In this manner, each time one line of recording is completed, the recording paper 105 and the ink film 105 are fed by one line in the sub-scanning direction to proceed with recording. Here, the adhesiveness between the ink film 102 and the recording paper 105 has a great influence on the image quality. Therefore, the conventional thermal head uses a partial glaze type in which a heating element portion is projected.

That is, the line-type thermal head has a full-face glaze type whose cross-sectional shape is flat as shown in FIG. 4 (a), and a partial glaze as shown in FIG. 4 (b) in which a heating element portion is projected. There are types. In any case, a heat insulating layer 101b is formed on a substrate 101a such as ceramic, a heat generating element 101c is formed on the resistance film, and a pair of electrodes 101d is formed on the heat generating element 101c except a heat generating portion. The protective layer 101e is formed so as to cover it, and the heat insulating layer 101b
A partially glaze type thermal head is a swelling shape in a semi-cylindrical shape. FIG. 5 shows a model of this partial glaze type thermal head. If the partial glaze part g is approximated by a cylinder with a radius R1, the reference "Timosheuko's" Th
From “P409 of eory of Elasticity” Maximum pressure P ₀ = 2F / πb (1) The nip width b is k1 = (1-ν1 ² ) / πE1 (3) k2 = (1-ν2 ² ) / πE2 (4) The pressure distribution P is Becomes Here, F is the pressing force applied to the thermal head 101, R1 is the radius of the platen roller 104, R2 is the radius of the partial glaze g of the thermal head 101, and E1 is the platen roller 104.
Young's modulus, E2 is Young's modulus of partial glaze g, ν1 is Poisson's ratio of platen roller 104, and ν2 is partial glaze g
In the Poisson's ratio, x is the coordinate value in the circumferential direction of the partial glaze g with the point A in FIG. 5 as the origin, and b is the nip width (contact width). When calculated by this formula, the pressure distribution is as shown in FIG. Here, when R2 → ∞, it becomes the most commonly used full-glaze thermal head.

As can be seen from this result, the maximum pressure of the partial glaze thermal head is higher than that of the full glaze thermal head. Therefore, the ink film and the recording paper are sufficiently brought into close contact with each other, so that good transfer can be performed. The recordable area is a portion of the heating element surface that is in close contact with the platen roller, and is an area of the heating element surface located within the nip width.

By the way, the shape of the heating element 101c of the thermal head is such that the length L in the sub-scanning direction is longer than the length l in the main scanning direction as shown in the enlarged view B in FIG. 7 (L> l). As a typical value, the length 1 in the main scanning direction is 110 μm, and the length L in the sub scanning direction is 190 μm. Then, using such a thermal head, one pixel (1 dot) is recorded once.

Here, the recording quality depends on the density of the recorded pixels
The more uniformly transferred in units of 101c, the better.
However, in practice, when the above-mentioned thermal head having the dot size is used, it is said that the recording density in the central part of the dot becomes thinner than that in the peripheral part because the ink in the central region having the highest pressure and temperature is pushed out to the peripheral side. There was a flaw.

Further, as shown in FIG. 3, the thermal head 101 is pivotally supported at one end and is rotatable in the direction of the arrow OS for setting the roll-wound recording paper 105 and the ink film 102. When opened in the direction of the arrow O, the thermal head 101 is separated from the platen roller 104 and the recording paper 105 or the like can be set. Then, after being set, when it is closed in the S direction, it is set to a steady position, and thermal transfer recording becomes possible. However, by such a rotating operation, the thermal head 101 as shown in FIG.
The center of the heating element 101c of is originally located at the position A,
For example, it may come to the position of A '. Such misalignment causes a positioning error within a range of about ± 100 μm with respect to the center due to the limit of mechanical accuracy, but in the worst case, it causes a deviation of 100 μm. Therefore, for example, if the center of the heat generating element 101c comes to the position A ', the width of the heat generating element 101c in the sub-scanning direction is 190 μm, so that even if the nip width is 150 μm from the center, 45 μm sticks out to one side. I will end up. In other words, the amount of W in FIG.
It will be out of the recordable area. And
Since the detached portion does not press the ink film, this portion cannot be thermally transferred.

Conventionally, the length L (= 19) of the heating element 101c in the sub-scanning direction is used.
Since the recording paper and the ink film are sub-scanned at a pitch of 0 .mu.m), a blank space having a width of 45 .mu.m is generated thereafter, and the quality of the recorded image is significantly deteriorated. This is a defect peculiar to the partial glaze type thermal head in which the heating element portion has a semi-cylindrical shape, and it has been a similar defect not only in the thermal transfer recording system but also in the thermal recording system using the thermal recording paper.

(Problems to be Solved by the Invention) As described above, in thermal transfer recording, an ink film is brought into contact with a recording paper and sandwiched by a thermal head and a platen roller, and a heating element of the thermal head is caused to generate heat in accordance with a recording signal to melt the ink to the recording paper. This is a transfer method.

When the thermal transfer recording method is used in a facsimile apparatus, a partial glaze line type thermal head in which a plurality of minute heating elements are densely arranged in a line in the main scanning direction is used.

Considering a general line type thermal head having a density of about 8 dots / mm, the heating element size of this thermal head is 110 μm in the main scanning direction and 190 μm in the sub scanning direction. In this case, since the glaze is a partial glaze, the contact pressure with the platen roller is higher than the peripheral portion in the direction of the central region of the heating element, and the adhesion is good. However, since the pressure in the peripheral portion is lower, the melted ink in the central portion flows in the sub-scanning direction due to the pressing pressure of the thermal head, so that the ink layer becomes thin in the central region and the recording density as a whole decreases. In addition, since the thickness of the ink layer changes, the ink peeling state is not stable, and it is not possible to record with a clean contour.

As described above, when the thermal head and the platen roller are in contact with each other, the pressure to push the ink is strong in the center of the heating element, and the pressure drops when the distance from the center to the lead wire direction is reduced, and the ink flow due to the pressure difference between the center of the heating element and the lead wire As a result, the thickness of the transferred ink is not uniform, and high-quality recording cannot be performed. Further, the thermal head can be brought into and out of contact with the platen roller with one end as an axis for setting a recording paper or an ink film. Although the positioning error is suppressed to about ± 100 μm, the width of the heating element is 190 μm. On the other hand, in the case of the partial glaze type, recording is possible only within the nip width, and the nip width is the same as the conventional standard. In this case, since it is about 300 μm, if it deviates from the center by ± 100 μm, an area in which 45 μm cannot be recorded occurs and the quality of the recorded image deteriorates not only in the thermal transfer recording system but also in the thermal recording system.

Therefore, an object of the present invention is to provide a recording apparatus that enables high-quality recording.

[Configuration of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. That is, using a partial glaze type thermal head in which a plurality of minute heating elements are densely arranged linearly and the arrangement direction is the line direction, and the direction intersecting the line direction is the recording paper feeding direction. In addition, in the recording apparatus configured to record the image information on the recording paper by giving the recording data of each pixel position in the line direction to the thermal head to cause the corresponding heating element to generate heat, the thermal head is provided for each of the minute heating elements. The width of the recording paper in the feeding direction is made narrower than the width in the line direction, and the feeding means feeds the recording paper in predetermined pitch units within the width of the minute heating element in the feeding direction of the recording paper, and by the control means. , The same recording data is repeated a plurality of times for each minute heating element of the thermal head until the recording of the width corresponding to one line is made. Obtain so.

(Operation) In such a configuration, the heating elements of the thermal head are configured so that the width in the recording paper feeding direction is narrower than the width in the line direction, and when the recording data for one line is given, the corresponding heating element is provided. This recording data is applied to the recording paper to control heat generation, and recording for one line is performed on the recording paper. When the recording of one line is completed, the feeding means feeds a predetermined unit pitch within the width of the minute heating element in the recording paper feeding direction, and again gives the same data as the previous recording data to the thermal head to record the same content. I do. Then, when the recording of the width corresponding to one line is completed, the control means updates the print data, and the next print is performed by the same operation as described above with the updated print data.

As described above, when the size of the minute heat generating element of the thermal head is configured such that the width in the recording paper feeding direction is narrower than the width in the line direction, the area recorded by one thermal transfer is small in the thermal recording method, so Since the pressure difference between the central portion and the peripheral portion on the paper feeding direction side is small, and the recording area is also small, the amount of ink flowing to the peripheral portion side is significantly smaller than in the conventional case. In the thermal transfer recording method and the thermal recording method, since the recording paper and the thermal transfer ink holder are fed by the unit pitch for a plurality of times with the same data to perform the recording for one line, the unevenness of the ink is also noticeable. High quality recording is possible.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view and a partially enlarged view showing the configuration of a partial glaze line type thermal head, which is an important component of the device of the present invention.

In the figure, 201 is a thermal head body, and 201a
Is a substrate. 201c is a minute heating element, which is densely formed in a plurality of lines (main scanning direction). The heating element 201c is formed on the substrate 201a, and its shape is as shown in the enlarged view A of FIG. That is, the length L in the recording paper feed direction (sub-scanning direction) is made shorter than the length 1 in the line direction (main scanning direction) (l <L).

By the way, in the shape of the heating element 101c of the conventional thermal head, as shown in the enlarged view B in FIG. 1, the length L in the sub-scanning direction is longer than the length l in the main scanning direction (L> l). .
As a typical value, the length 1 in the main scanning direction is 110 μm, and the length L in the sub scanning direction is 190 μm. Then, using such a thermal head, one pixel (1 dot) is recorded at one time.

In the apparatus of the present invention, this is 100 μm in the main scanning direction l.
Although there is no change, the length L in the sub-scanning direction is set to about 90 μm, which is about half that of the conventional one.

Except for the size of the heating element, the basic configuration is the same as the conventional one described above.

The adjacent heating elements 201c are electrically separated from each other by an insulating layer 201f, and one end side of the heating element 201c is connected to a common lead wire 201d which is a common side, and the other end side is connected to an independent lead wire 201d. The lead wire 201d is connected to the ground via a driving transistor, and the common lead wire 201e is connected to, for example, a + 24V power supply line, so that the transistor is turned on / off by an image data (recording data) signal. Then, the heating element 201c is energized according to the data to control the heat generation.

FIG. 2 shows a block diagram of a thermal transfer recording apparatus according to the present invention using a thermal head having such a structure. Here, the receiving side of the facsimile device is taken as an example.
Reference numeral 201 is the above-mentioned thermal head, and 202 is a buffer for giving recording data to the thermal head 201. This buffer 202
Is for temporarily storing print data corresponding to each of the minute heat generating elements 201c of the thermal head 201, and energization of each of the minute heat generating elements 201c is controlled according to the data given from the buffer 202. 203 is a demodulation unit for demodulating a data signal transmitted through the line, 204
Is a decoding unit that decodes image data from the demodulated data signal, 205 is a control unit that controls the entire system, and records the image data every time the decoding unit 204 outputs the image data for one line. The stop command is released for a predetermined time, and when the page cutting and the reception of the image data are completed, the cutting control of the recording paper by the cutter mechanism (not shown) and the discharging control of the recording paper are also performed. 20
Reference numeral 6 denotes a recording control unit, which is a decoding unit under the control of the control unit 205.
The image data from 204 is sequentially captured and held, and when the recording stop command is released, the holding data for one line is given to the buffer 202, and the recording command is given to execute recording and feeding twice, and this recording control is performed. By this, the control is performed such that the image data of the next line is given to the buffer 202 such that the feed command is given twice.

Reference numeral 207 denotes a motor drive control unit which generates a drive pulse signal for feeding one pitch each time a feed command from the recording control unit 206 is received. Reference numeral 208 denotes a transport motor for feeding a recording paper or an ink film (thermal transfer ink holder), which is rotated one pitch each time the drive pulse signal is received. Where 1
In the case of the present embodiment, since the length L of the minute heating element 201c in the sub-scanning direction is half that of the conventional one, the pitch is half the width of one line of general recording, and when two pitches are fed, the feed amount is equivalent to the width of one line. It is designed to be This can be easily realized by making the reduction ratio of the reduction mechanism attached to the motor double the conventional reduction ratio.

In this device having such a configuration, when a data signal arrives, it is demodulated by the demodulation unit 203 and decoded by the decoding unit 204 to become image data. Then, every time the image data for one line is obtained, the control unit 205 gives the recording stop instruction given to the recording control unit 206 for a predetermined time. On the other hand, the recording control unit 206
Captures the decoded image data sequentially, and gives the image data for one line captured during this period to the buffer 202 by releasing the recording stop signal. Then, when the recording stop command is released, the recording control unit 206 next generates a recording start command. By this series of controls, the buffer 202 temporarily holds the image data for the first one line output from the recording control unit 206, and supplies this to the corresponding minute heating elements of the thermal head 201. Therefore, each of the minute heat generating elements is energized and controlled according to the image data to generate heat, melt the ink in the ink film, and transfer the ink to the recording paper. At the timing when the transfer is completed, the recording control unit 206 generates a feed command, and the motor drive control unit 207 generates one drive pulse signal accordingly, so that the carry motor 208 rotates one pitch. Since one pitch in this case is half of the width corresponding to one recording line, it is the conventional conveyance pitch.

As a result, the recording paper and the ink film are sent by the width of one half of the line, and at this time, the recording control unit 206 drives each minute heat generating element of the thermal head 201 again by the image data of the buffer 202 to execute the recording. A feed command is generated to execute the conventional half-pitch feed.
Therefore, recording with the same image data as the previous time is performed again, and recording for one line is completed.

When the recording for one line is completed, the recording control unit 206 takes in the image data output from the decoding unit 204 while waiting for the recording stop command to be released again. Then, when the recording stop command is released, the recording control unit 206 reads the image data for the next one line that is already held and gives it to the buffer 202, and also generates a recording start command and a feed command. As a result, the thermal head 201 generates heat in accordance with the data held in the buffer 202, and the motor drive control unit 207 generates one drive pulse signal, so that the carry motor 208 rotates one pitch. As a result, the recording paper and the ink film are rotated by an amount corresponding to half the conventional pitch, that is, an amount corresponding to half the width of one line of recording, and the recording paper and the ink film are fed by the width of one half of one line. Therefore, half line recording is performed with new image data. When this is finished, the recording with the same image data and the feeding for the half line are performed again, and the recording for the one line in which the recording with the same image data as the previous time is performed again is completed.

When the recording stop command is released after the recording of one line is completed, the recording control unit 206 reads the image data of the next one line that is already held, gives it to the buffer 202, and executes the feeding again. The same operation as described above will be repeated.

When the end of the page is reached or the reception is completed, the control unit 205 issues a page cut command, cuts the recording paper, ejects the recorded recording paper, and records again as described above by the image data of the next page. You will be in control.

In the case of such a recording method, as shown in FIG. 9, the state of the recording pixels is such that the recorded image of the first line is the pixel 1
a, 2a ..., The recorded image of the second line is formed by the pixels 1b, 2b ... (See FIG. 9 (a)), but in this method, as shown in FIG. 9 (b), The upper half of one line is pixel 1a-
, 1a-2, 2a-2, ..., the lower half of the first line is formed by the pixels 1a-2, 2a-2 by the same image data, completing the first line, and then the second line. A half of the pixels is formed by the pixels 1b-1, 2b-1 ... According to the image data of the next line, and then the pixels 1b-2, 2b-2 of the lower half of the second line are formed by the same image data. Will be recorded in.

When the size of the minute heat generating element of the thermal head is configured such that the width in the recording paper feeding direction is narrower than the width in the line direction, the area recorded by one thermal transfer is narrow. Since the pressure difference from the peripheral portion on the direction side is small and the recording area is also small, the amount of ink flowing to the peripheral side is significantly smaller than in the conventional case. Then, the recording paper and the thermal transfer ink holder are fed by a unit pitch, and recording is performed a plurality of times using the same data, and recording for one line is performed, so that unevenness of ink is not noticeable and high-quality recording is possible. Become.

Further, as shown in FIG. 3, the thermal head 101 is pivotally supported at one end and is rotatable in the direction of the arrow OS for setting the roll-wound recording paper 105 and the ink film 102. When opened in the direction of the arrow O, the thermal head 101 is separated from the platen roller 104 and the recording paper 105 or the like can be set. Then, after being set, when it is closed in the S direction, it is set to a steady position, and thermal transfer recording becomes possible. However, by such a rotating operation, the thermal head 101 as shown in FIG.
The center of the heating element 101c of is originally located at the position A,
For example, it may come to the position of A '. Such misalignment causes a positioning error within a range of about ± 100 μm with respect to the center due to the limit of mechanical accuracy, but in the worst case, it is misaligned by 100 μm, for example, if the position is A ′. For example, in the case of the conventional heating element 101c, the width in the sub-scanning direction is 19
Since it is 0 μm, even if the nip width is 150 μm with respect to the center, it will protrude to one side of 45 μm. That is, the eighth
The portion W in FIG. 7A is out of the recordable area. In the case of a partial glaze thermal head, this detached portion does not press the ink film, so that this portion cannot be thermally transferred.

As described above, in the conventional case, since the recording paper and the ink film are sub-scanned at the pitch of the length L (= 190 μm) in the sub-scanning direction of the heating element 101c, a blank space having a width of 45 μm occurs thereafter, and the quality of the recorded image is significantly deteriorated. It was decided to let me.

However, in the present invention, the length of the minute heating element 201c in the sub-scanning direction is 90 μm, which is half that of the conventional one. Therefore, even if the thermal head is deviated by 100 μm from the center as shown in FIG. The end portion of the heating element 201c stays at a position displaced by a maximum of 145 μm, and since this has a nip width of 150 μm on one side with respect to the center, it is within the recordable area.

That is, in the apparatus of the present invention, even when the thermal head is set, even if there is a positional deviation of the maximum difference, the entire surface of the heating element 201c fits within the nip width, and the entire heating element can be used for recording. Since the feed in the sub-scanning direction corresponds to the width of the heating element in the sub-scanning direction, there is no fear of causing a gap in the recorded image as in the conventional case, and high-quality recording can be performed.

As described above, in order to obtain good recording in thermal transfer recording, a line-type thermal head with partial glaze is used, but this reduces the nip width, and in the conventional heating element size, heat is generated due to the positioning variation between the heating element and the platen roller. The element sometimes protruded beyond the area of the nip width.

According to the present invention, the shape of the heating element is made shorter in the sub-scanning direction than in the main-scanning direction so that even if there is a variation in positioning, the heating element is within the nip width, so that good image quality can be obtained.
Since one pixel is shifted a plurality of times for recording as much as it becomes shorter, the image signal can be faithfully recorded. Further, since the heating element has a smaller area than the conventional one, the dispersion of the ink due to the pressure difference at the time of transferring the ink is reduced, and the transferred ink layer becomes uniform, so that high quality recording can be performed.

The present invention is not limited to the embodiments described above and shown in the drawings, and can be carried out by appropriately changing the paper within a range where the paper is not changed, and the width in the sub-scanning direction with respect to the width in the main scanning direction of the heating element. Are not limited to the examples. Also. With respect to the problem that the above-mentioned heat generating element protrudes from the region of the nip width, the same effect can be obtained not only in the thermal transfer recording system but also in the thermal recording system.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a recording apparatus capable of obtaining a high-quality recorded image.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the configuration of a thermal head used in the apparatus of the present invention, FIG. 2 is a block configuration diagram of a receiving system of a facsimile apparatus showing an embodiment of the present invention, and FIG. 3 is a diagram of a thermal transfer recording apparatus. FIG. 4 is a schematic view for explaining the structure, FIG. 4 is a cross-sectional view of a main part for explaining the structure of the thermal head, and FIG.
FIG. 6 is a diagram showing the contact state of the partial glaze thermal head with the platen roller, FIG. 6 is a diagram for explaining the pressure distribution by type of the thermal head under the contact state in FIG. 5, and FIG. 7 is a conventional part FIG. 8 is a diagram for explaining the structure of a glaze line type thermal head, and FIG. 8 is a diagram for explaining the relationship between the positioning error and the thermal transfer effective area of the heating element in the thermal head having the conventional structure and the structure according to the present invention. FIG. 9 is a diagram for explaining the recording states of the conventional method and the present invention method. 201: Thermal head body, 201a: Substrate, 201c ...
Heating element, 201d ... Lead wire, 201e ... Common lead wire, 201f ... Insulating layer, g ... Partial glaze, 202 ... Buffer, 203 ... Demodulation section, 204 ... Decoding section, 205 ... Control section , 206 ... Recording control unit, 207 ... Motor drive control unit, 20
8: Transport motor.

Claims (1)

(57) [Claims] 1. A partial glaze type thermal head in which a plurality of minute heating elements are densely arranged linearly and the arrangement direction is a line direction, and a recording paper is fed in a direction intersecting the line direction. Recording data at each pixel position in the line direction and in the line direction is applied to the thermal head to cause the corresponding heating element to generate heat, thereby recording image information on the recording paper. A width of a feed direction of the recording paper of each element is narrower than a width of the line direction, and a feeding means for feeding the recording paper in a predetermined pitch unit within the width of the minute heating element in the recording paper feed direction, And a control means for repeatedly applying the same recording data to each of the minute heat generating elements of the thermal head a plurality of times until the recording of the width corresponding to the line is completed. Recording apparatus characterized by constituting the.