JP2002240340A - Method for serial printing and serial printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print high-quality images by detecting dimmed images, recovering and recording the images. SOLUTION: A carriage 19 moves back and forth in a breadthwise direction of a recording paper 10. A thermal head 18 and a density-measuring sensor 21 are fixed to the carriage 19, and also an ink ribbon cassette 24 is mounted to the carriage 19. When the carriage 19 moves forward in a direction of an arrow A, the thermal head 18 thermally records one line. When the carriage 19 moves back in a direction of an arrow B after the one line is recorded, the density-detecting sensor 21 measures a density of each pixel of the one line. An estimated density obtained from image data is compared with the actually measured density measured by the density-measuring sensor 21 for each pixel. When there is a difference of a fixed value or more between the estimated density and the actually measured density, the image is dimmed or has a density irregularity. At this time, the carriage 19 moves forward to drive the thermal head 18 in accordance with the density difference of each pixel, so that the one line is recovered and recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printing method and a serial printer for performing printing while repairing a printing defect, and a serial printing method and a serial printer for preventing a line from being blank due to a failure of a printing element. .

[0002]

2. Description of the Related Art In a serial printer, a recording head is reciprocated in a width direction of a recording material to record one line or several lines, and it takes a long time to perform printing. Widely used as personal printer.

[0003] Serial printers include a thermal recording printer that heats a thermal recording paper with a thermal head and performs color recording.
An ink jet printer that records images by attaching ink dots ejected from an ink jet recording head to recording paper (such as high-quality paper), and records an image by heating the ink ribbon from the back and transferring the melted or sublimated ink to the recording paper. Thermal transfer printers.

[0004] For example, in a serial printer for performing thermal transfer recording of a fusion type, a carriage that holds a thermal head and moves in the width direction of the recording paper, and a carriage that moves in the longitudinal direction of the recording paper.
A transport unit for transporting the recording paper is provided, and the ink melted by heating the ink ribbon by the thermal head is transferred to the recording paper while moving the thermal head in the width direction. Then, after recording for one line or several lines, the recording paper conveying means feeds the paper for one line or several lines to prepare for the next recording. By repeating this, an image is recorded on the recording paper.

Although not unique to a serial printer, the printed image may be blurred (density unevenness) or the density of the entire image may be insufficient, and the cause varies depending on the type of printer. For example, in thermal recording printers and thermal transfer printers, if the pressure of the thermal head changes momentarily due to the influence of vibration or the voltage applied to the head temporarily changes, the printed image will be partially blurred. appear.

Further, in the thermal recording printer, when the humidity changes, the coloring characteristics of the thermal recording paper change, so that the density of the entire image becomes insufficient. Further, the density may be insufficient due to the aging of the thermal recording paper. In a thermal transfer printer, the transfer efficiency of ink varies depending on the paper quality of the recording material to be used. If the paper quality is poor, the density of the image becomes insufficient.

[0007] In an ink jet printer, the bleeding of the ink changes depending on the paper quality of the recording material, so that the image density may be insufficient. Further, the image may be blurred due to the temporary clogging of the nozzles or the temporary fluctuation of the amount of the ejected ink droplets.

If the printed image is blurred or lacks density, reprinting is necessary, which leads to waste of consumables such as recording materials and ink and waste of time.

In order to cope with the above-described image blurring and insufficient density, for example, in a serial printer described in JP-A-6-328675, a test pattern is recorded before an image is recorded, and the density of the test pattern is determined. The measurement is performed, and if blurring or the like has occurred, the image is recorded after the driving conditions of the recording head or the image processing conditions are changed. In the thermal transfer serial printer described in JP-A-6-297823, the density of each portion printed on a recording material is measured by a sensor attached near a recording head. Informs the user that the service life has expired and it is time to replace it, and urges the user to replace the ink ribbon.

[0010]

However, as in the serial printer described in Japanese Patent Application Laid-Open No. 6-328675, even if the driving conditions of the recording head are changed before recording an image, each line is sequentially changed. If environmental conditions such as humidity, fluctuations in the voltage of the recording head, or clogging of nozzles occur during recording, a partial lack of density (density unevenness) also occurs in the image. In addition, Japanese Unexamined Patent Publication No.
In the serial printer described in Japanese Patent Publication No. 297823, if a replacement ink ribbon is not prepared, image recording cannot be performed immediately, and time may be wasted.

Further, when a heat-generating element in a thermal recording printer or a thermal transfer printer fails, the heat-sensitive recording paper or ink ribbon cannot be heated, and the line facing the defective heat-generating element becomes white. It will be in a state of being put away. Also, when the nozzles of the ink jet printer are completely clogged, a state in which the line is whitened similarly occurs. Alternatively, in the serial printer described in the above-mentioned publication, an image is recorded, and if the density of the image is insufficient (density unevenness) with respect to the recording material once discharged to the outside, this is corrected to obtain a normal image. How to do it is not considered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In the case where the image is blurred or the density is insufficient, the correction is performed during printing, and the printing element such as a heating element or a nozzle is damaged. It is an object of the present invention to provide a serial printer that prevents occurrence of a blank line in a case, or corrects fading or insufficient density of a recording material discharged once to the outside. And

[0013]

In order to achieve the above object, according to the serial printing method of the present invention, when a printing failure occurs on a recorded line, the line is corrected and recorded. I have. Preferably, the recording material is a thermosensitive recording paper having a thermosensitive coloring layer, and the recording head is a thermal head that heats the thermosensitive coloring layer to color-record an image. Further, the recording head may be a thermal head for recording an image by transferring ink melted or sublimated by heating an ink ribbon from behind to a surface of the recording material, or a recording head by discharging ink to record the image. An ink jet recording head that records an image on a recording medium may be used.

In a serial printer according to a fifth aspect of the present invention, a carriage reciprocating in the sub-scanning direction, which is the width direction of the recording material, and a predetermined number of lines held by the carriage and corresponding to image data during the forward movement. A recording head for recording on a recording material, the recording head being attached to the carriage, and while the carriage is moving backward, a density measurement for measuring each portion recorded during the forward movement of the carriage to obtain an actually measured density. Means, density predicting means for obtaining from the image data the density to be recorded in each part as a predicted density, and comparing the measured density with the predicted density for each part so that the measured density has reached the predicted density. When there is no calculation means for calculating the density difference, and when there is a portion having the density difference,
When the carriage is reciprocated again, and a portion having a density difference during the forward movement is driven by a recording head in accordance with the density difference to perform correction printing, and a portion having the density difference does not exist. Is provided with a recording material conveying means for conveying the recording material in the main scanning direction in order to record the next predetermined number of lines on the recording material.

According to a sixth aspect of the present invention, there is provided a serial printer which reciprocates in a sub-scanning direction which is a width direction of a recording material, and which is held by the carriage and records a predetermined number of lines according to image data during the movement. A recording head for recording on a material, one of which is located on both sides of the recording head, one of which is selected according to the moving direction of the carriage, and the first and second for measuring each part immediately after recording to obtain an actual measured density. 2, a density measuring means, a density predicting means for obtaining a density to be recorded in each portion as a predicted density from image data, and comparing the measured density and the predicted density for each portion,
When the measured density does not reach the predicted density, the calculation means for obtaining the density difference, and when there is a portion having the density difference, the carriage is moved again, and the portion having the density difference is moved during the movement. Correction recording means for driving a recording head in accordance with the density difference to perform correction recording, and when there is no portion having the density difference, recording is performed to record the next predetermined number of lines on the recording material. Recording material conveying means for conveying the material in the main scanning direction.

It is preferable that the density measuring means includes a light projecting section for illuminating each recorded portion, and a light receiving section for converting the reflected light into an electric signal. Further, it is preferable that each of the parts is one pixel.

According to a ninth aspect of the present invention, a recording head having a plurality of recording elements arranged in the main scanning direction is moved in the sub-scanning direction, and a predetermined number of lines are recorded in accordance with image data during the movement. If a faulty recording element that has become unrecordable due to a failure is detected among the plurality of printing elements, the printhead is moved again, and a line to be originally recorded by the faulty recording element is separated. Is recorded by an effective recording element.

In the serial printer according to the tenth aspect,
A carriage that reciprocates in the sub-scanning direction that is the width direction of the recording material; and a plurality of recording elements that are held by the carriage and arranged in the main scanning direction. A recording head for recording the recording material on the recording material, means for transporting the recording material in the main scanning direction, and mounted on the carriage, for measuring each line on which recording was performed by the recording head, to obtain an actually measured density. Density measuring means, when the measured density does not reach a predetermined value, failure determination means for determining the recording element that has recorded the line as a failure recording element, and M recording elements arranged in the main scanning direction. If all of the elements are valid, M
Recording is performed while transporting the recording material line by line, and when the failure determination unit determines that the recording element has failed, the recording material is transported in the main scanning direction by at least one line, and the line allocated to the failed recording element is removed. The recording element is driven, and the carriage is reciprocated in the sub-scanning direction so that recording is continued while the recording material is conveyed in the main scanning direction according to the number of effective recording elements. And control means for controlling the conveyance of the recording material in the main scanning direction.

In the serial printer according to the eleventh aspect,
When the number of consecutively arranged effective recording elements is N,
While transporting the recording material in the main scanning direction by N lines,
Recording is performed by the number of effective recording elements.

In the serial printer according to the twelfth aspect,
When all of the M recording elements arranged in the main scanning direction are valid, the recording material is conveyed by (M−A) lines, and recording is performed by overlapping each of A lines, and the failure determination means is used. When it is determined that the recording element has failed, the recording material is conveyed by at least one line in the main scanning direction, and the line allocated to the failed recording element is recorded by the valid recording element. Control for controlling the driving of the recording element, the reciprocation of the carriage in the sub-scanning direction, and the conveyance of the recording material in the main scanning direction so as to continue printing while conveying the recording material in the main scanning direction according to Means are provided.

In the serial printer according to the thirteenth aspect,
When the number of consecutively arranged effective recording elements is N,
While the recording material is conveyed in the main scanning direction line by line (N-A), recording is performed by N effective recording elements overlapping by A lines.

According to a fourteenth aspect of the present invention, after an image is once recorded on a recording material, the recorded recording material is loaded again, and a line where a printing failure occurs among the recorded lines is performed. Is corrected and recorded for that line.

In the serial printer according to the fifteenth aspect,
A carriage that reciprocates in a sub-scanning direction that is a width direction of the recording material, a recording head that is held by the carriage, and that records a predetermined number of lines on the recording material according to image data during the movement; And conveying means for conveying in the scanning direction, when the recorded recording material is loaded,
An image recording area recognizing means for recognizing position information of an image recording area in which an image is recorded, and a positional shift in the main scanning direction and the sub-scanning direction between the position information of the image recording area and the position information based on the image data. , And inclination, and the image data is inclined according to the displacement of the position and the inclination.
And corrected image data creating means for creating the moved corrected image data, and attached to the carriage,
After the image recording area is recognized, the carriage is moved.During the movement of the carriage, each part of the image recording area is measured, and a density measuring unit for obtaining an actual measured density is provided. Density prediction means for obtaining the density to be recorded in each part in the image recording area as a predicted density, and comparing the measured density and the predicted density for each part, so that the measured density becomes the predicted density. If it has not reached, the calculation means for obtaining the density difference, and if there is a portion having the density difference, the carriage is moved again, and the portion having the density difference is moved according to the density difference during this movement. Correction recording means for driving the recording head to perform correction recording.

In the serial printer according to the sixteenth aspect,
The image recording area recognition unit performs the movement of the carriage, and the conveyance of the recording material by the conveyance unit,
During the movement and transportation, the boundary between the portion where the image is formed and the surrounding portion is detected by the density measuring means to recognize the image recording area.

[0025]

FIG. 1 shows a thermal transfer serial printer embodying the present invention. In the thermal transfer serial printer 1, a long recording paper 10 is set in a paper supply unit (not shown) in a state of being wound in a roll shape. The recording paper 10 is pulled out of the paper feed unit by a paper feed roller pair 12 and passed through a transport roller pair 11. A leading edge detection sensor 17 is disposed downstream of the transport roller pair 11 and
Is detected, a detection signal is sent to the system controller 16. When receiving the leading edge detection signal, the system controller 16 shifts the pinch rollers of the pair of transport rollers 11 to nip the recording paper 10.

The paper feed roller pair 12 and the transport roller pair 11
It is driven by a transport motor, for example, a pulse motor 14. The rotation of the pulse motor 14 is controlled by a system controller 16 via a driver 15. During printing, the conveying roller pair 11 rotates forward to intermittently feed the recording paper 10 by a predetermined width in the arrow direction (main scanning direction). During this intermittent feeding, the head section 22 reciprocates in the sub-scanning direction, and sequentially records three color lines. A cutter 13 is arranged downstream of the pair of conveying rollers 11, and separates a printed portion into sheets. This sheet is discharged to the outside by a discharge roller pair (not shown). Note that a cut sheet of a predetermined size may be used instead of the roll paper.

The head section 22 includes a carriage 19, a thermal head 18 held by the carriage 19, and a density measurement sensor 21. A cassette 24 containing a sublimation type ink ribbon 23 is exchangeably mounted on the carriage 19. Carriage 19
The belt 2 is inserted through a guide shaft 26 extending in the sub-scanning direction, and is hung on a pair of pulleys 27a and 27b.
8 is partially connected.

The pulleys 27a and 27b are motors, for example,
Driven by a pulse motor 29. Pulse motor 2
When 9 rotates in the forward direction, the carriage 19 moves in the direction of arrow A (hereinafter referred to as forward movement), and when rotated in the reverse direction, moves in the direction of arrow B (hereinafter referred to as return movement). Pulse motor 2
Numeral 9 rotates in response to a signal and a drive pulse in the rotational direction (forward / reverse) from the driver 31.

In FIG. 2, the thermal head 18 includes
A heating element array 34 is formed. The heating element array 34 includes a plurality of heating elements 34a, 34b, 34c, 34d, 34e, 34 in the main scanning direction M as shown in FIG.
f are arranged, and the width W is recorded by moving in the sub-scanning direction S. In this example, since there are six heating elements 34a to 34f, the width W is equivalent to six lines. Thermal head 1
8 is a retracted position indicated by a solid line in the figure by a solenoid or the like;
It rotates between the print position indicated by the two-dot chain line. At the printing position, the recording paper 10 is pressed between the heating element array 34 and the platen 20. At the retracted position, the heating element array 34 moves away from the recording paper 10.

The cassette 24 rotatably accommodates a supply reel 37 around which an unused ink ribbon is wound inside a cassette body 36 and a take-up reel 38 for winding up a used ink ribbon. is there. A notch 39 into which the thermal head 18 is inserted is formed in front of the cassette body 36. In addition, an ink ribbon 23 coated with ink is drawn out from the inside of the cassette body 36 and passed through the front of the notch 39. Notch 39
The thermal head 18 that has entered the ink ribbon 23
Is heated from the back side to perform thermal transfer onto the recording paper 10.

As shown in FIG. 3, the ink ribbon 23
Yellow ink area 23a, magenta ink area 2
3b and the cyan ink area 23c are repeatedly formed. The length of each of the areas 23a to 23c is
, And a color image having a predetermined width W is recorded by three areas. Note that, in addition to these three colors, four colors including a black ink area may be used. Such an ink ribbon and a cassette for accommodating the ink ribbon are described in detail in, for example, JP-A-7-276761.

The density measuring sensor 21 is provided on one side of the carriage 19. This concentration measuring sensor 21 is shown in FIG.
As shown in the figure, the lighting unit 41, the light receiving unit 42, and the case 4
And 3. The lighting unit 41 includes a light source 45,
It comprises a condenser lens 46 for condensing light from the light source 45 onto the recording surface 10a of the recording paper 10. The light receiving section 42
It comprises a light receiving lens 47, a filter turret 49 for selecting any one of red, green and blue light wavelengths, and a light receiving sensor 48. As the light receiving sensor 48, a CCD image sensor is used, and as shown in FIG.
Six pixels 50 (shown by hatching) recorded simultaneously in 4a to 4f are individually measured. The case 43 includes the lighting unit 4
Openings 43a and 43b are formed on the front surface so as to hold the light receiving unit 42 and the light receiving unit 42 and expose the light source 45 and the light receiving sensor 48 via the condenser lens 46 and the light receiving lens 47, respectively.

As shown in FIG. 5, an image processing section 51, a motor driver 15, a motor driver 31, a counter 32, a counter 52, a head control section 54, and a cutter driving section 55 are connected to the system controller 16. The print instruction is issued by the operation unit 56. The image processing unit 51 converts blue, green, and red image data input from a scanner, an electronic still camera, and the like into yellow,
The image data is converted into image data of three colors of magenta and cyan and then written to the image memory. Then, at the time of reading, the gradation is converted in accordance with the recording characteristics of the printer, and then sent to the head controller 54 and the density estimator 59.

When the leading edge detection sensor 17 detects the leading edge of the recording paper 10, the system controller 16 operates a counter 32 that counts driving pulses, and measures the amount of recording paper 10 being fed. The print size, recording start position, and recording end position of the recording paper 10 are determined in advance, and these positions are controlled based on the count value of the counter 32. At the time of printing, the pulse motor 14 is intermittently driven, and the recording paper 10 is fed by a predetermined interval W every time thermal transfer recording for six lines is completed.

The system controller 16 rotates the pulse motor 29 and operates the counter 52 to measure the amount of movement of the carriage 19 from the count value of the drive pulse. The head controller 54 is controlled based on the count value of the counter 52.

The head controller 54 controls the amount of heat generated by each of the heating elements 34a to 34f of the thermal head 18 based on the image data from the image processor 51 and drives the shift mechanism 57. The shift mechanism 57 displaces the thermal head 18 and presses the ink ribbon 23 against the recording paper 10.

The signal output from the light receiving sensor 48 of the density measuring sensor 21 is subjected to logarithmic conversion and complementary color conversion in the conversion unit 58, and is converted into pseudo densities of yellow, magenta, and cyan. Also, yellow of the image to be printed,
The pixel data of each of the magenta and cyan pixels is converted into a dot density on the recording paper 10 by the density prediction unit 59. This density conversion can be performed by using a conversion table representing the relationship between the image signal and the density.

The density from the conversion unit 58 is an actually measured density.
The density from the density predicting section 59 is sent to the comparing section 60 as a predicted density, and is compared for each color and for each pixel. Only when the former value is small, the density difference is calculated. Sent to The presence of this density difference is when the pixel is blurred and the density is uneven. The system controller 16 creates corrected print data to make the density difference “0” and sends it to the head control unit 54 for repair recording.

Next, the operation of the present embodiment will be described with reference to the flowchart shown in FIG. When a print instruction is issued from the operation unit 56, the system controller 16 reads out one frame of image data from the image processing unit 51 and converts the blue, green, and red image data into yellow, magenta, and cyan images. . The image data of these three colors is sent to the density prediction section 59, and the predicted density of each color is calculated for each pixel. After calculating the predicted density, the recording paper 10 is fed, and the pulse motor 14 starts rotating forward. The recording paper 10 is sent out from a paper supply unit, nipped by a pair of paper supply rollers 12, and conveyed toward a pair of conveyance rollers 11. When the leading edge of the recording paper 10 is detected by the leading edge detection sensor 17, one of the transport roller pairs 11 shifts to nip the recording paper 10.

After the recording paper 10 is nipped by the conveying roller pair 11, the counter 32 operates. Then, when the conveying roller pair 11 slightly rotates and the recording start position faces the thermal head 18, the recording of the yellow image is started.
At this time, the tip of the yellow ink area 23 a of the ink ribbon 23 is located at the position of the thermal head 18. First, the head controller 54 moves the position of the thermal head 18 to the print position, and then reads out one line of yellow image data from the image processor 51 and sends it to the thermal head 18. System controller 16
Next, the pulse motor 29 is rotated forward, the head section 22 is moved forward, and the thermal head 18 is driven in synchronization with the forward movement based on the image data for six lines. At the same time, the reels 37 and 38 of the cassette 24 are rotated. As a result, each of the heating elements 34a to 34f generates heat at a temperature corresponding to the density to be recorded, and the first line of the yellow image is recorded on the recording paper 10 with a width W. FIG. 6 shows a state where the Nth line is recorded.

When the thermal transfer recording for six lines of the yellow image is completed and the head section 22 reaches the stroke end, the system controller 16 stops the forward movement of the head section 22 and also releases the thermal head 18 to the retreat position. . Next, the density measurement sensor 21 is driven to turn on the light source 45, and the filter turret 49 is rotated to set the blue light filter. The pulse motor 29 is rotated in the reverse direction to move the head portion 22 backward. In synchronization with the backward movement, the yellow image of six lines recorded during the forward movement is illuminated, and the amount of reflected light is measured by the light receiving sensor 48. I do. This allows
As shown by hatching in FIG. 6, the reflected lights of the six pixels 50 recorded simultaneously are separately measured.

Each signal of the six pixels output from the light receiving sensor 48 is converted by the converter 58 into an actually measured density of yellow. The measured densities of the obtained six pixels are compared with the comparison unit 60.
Sent to Predicted densities of the corresponding six pixels are input to the comparing unit 60 from the density estimating unit 59, and a density difference is calculated for each pixel. System controller 16
If the difference between the measured density and the predicted density is within a certain value, it is determined that the density is in an appropriate range. In this case, the recording of the yellow image ends, and the recording of one line of the magenta image starts.

If the measured density is smaller than the predicted density and the difference exceeds a certain value, the system controller 16 determines that the density is insufficient, and corrects the lack of the density by yellow correction printing. Create data for each pixel,
The yellow image is recorded again. At this time, the tip of the used yellow ink area 23a is
Rewind to face. Note that the reels 37 and 38 may be idled to the tip of the next unused yellow ink area 23a. Then, the system controller 16
Moves the thermal head 18 to the print position, moves the head unit 22 forward again, and drives the thermal head 18 in synchronization with the forward movement based on the corrected print data. As a result, each of the heating elements 34a to 34f is heated to a temperature corresponding to the insufficient density, and one line of the yellow image is recorded on the recording paper 10 again. And the head part 22
The density of the yellow image for six lines is measured again in synchronism with the return of. In this way, the correction print recording and the density measurement are performed, and the process is repeated until the difference between the actually measured density and the predicted density falls within a certain value.

When the thermal transfer recording for one line of the yellow image is completed, the take-up reel 38 of the cassette 24 rotates,
Take up the ink ribbon 23 and set the magenta ink area 2
The tip of 3b is aligned with the thermal head 18. As described above, after shifting the thermal head 18 to the recording position, the head unit 22 is moved forward. During this forward movement, the heating element array 34 is driven based on the magenta image data, and the first line of the magenta image is recorded on the recording paper 10. Thus, the six magenta dots arranged in the main scanning direction overlap with the six yellow dots previously recorded.

After the recording of the first line of the magenta image, while the head unit 22 moves back, the density measurement of six lines of the first line is performed. To restore and record the first line. Similarly, thermal transfer recording for one line of the cyan image is performed. At this time, since the yellow ink has sub-absorption of the magenta and cyan components and the magenta ink has the sub-absorption of the cyan component, the predicted density is calculated including these sub-absorption components.

When recording of one line of image is completed by three-color line sequential, the system controller 16 rotates the pulse motor 14 forward to feed one line (width W) of paper as described above. The next one line is recorded. Hereinafter, similarly, an image is recorded on the recording paper 10. In this way, since the difference between the measured density and the predicted density is recorded within a certain value for each row for each color, the image formed on the recording paper may be blurred or uneven in density. Even this will be repaired.

After the image is recorded, the conveying roller pair 11 rotates slightly, and the rear end of the recorded portion is set at the position of the cutter 13. The system controller 16 operates the cutter 13 via the cutter driving unit 55 to cut the recording paper 10 into a sheet and discharge the recording paper 10 out of the printer 1.

Subsequently, when printing is instructed, the counters 32 and 52 are reset, and the next image is printed on the recording paper 10 as described above. When the power is turned off, the pulse motor 14 rotates in the reverse direction, and the recording paper 10 is rewound to the paper feeding unit.

Although a plurality of lines are recorded by a plurality of heating elements, only one heating element may be provided in the thermal head 18 and recording may be performed line by line. In this case, the density measurement sensor 21 measures each dot on this line in order.

In addition to the failure of the heating element, the densities of a plurality of dots recorded at the same time often vary in the same manner. Therefore, for example, common corrected print data may be created by averaging the densities of six dots and calculating the average measured density.

Next, a second embodiment of the present invention will be described. In this embodiment, recording of an image and measurement of density are performed simultaneously. In this case, as shown in FIG. 8, the density measurement sensors 21A and 21B are respectively disposed before and after the thermal head 18 in the sub-scanning direction. Note that the same members as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, the head portion 22 is
When moving in the direction, for example, a predetermined number of lines is recorded for yellow. During this recording, the density measurement sensor 2
1B measures the yellow dot immediately after recording. An actual measured density is obtained from the measurement of the density measuring sensor 21B, and is compared with the predicted density to create corrected print data.

When the head section 22 moves in the direction of arrow B, the thermal head 18 is driven to perform repair recording on the corrected print data. During the restoration recording, the density measurement sensor 21A is used.
And compare again with the predicted concentration. If the repair record is almost complete and each pixel is recorded at approximately the expected density,
The next magenta recording is performed.

If the repair recording is incomplete, the repair recording is performed again when the head section 22 moves in the direction of arrow A. If the re-repair recording is complete, magenta recording is performed when the head unit 22 moves in the direction of arrow B.
Therefore, although the recording directions of the main recording and the repair recording are not fixed, printing can be performed at high speed because recording and density measurement are performed simultaneously.

In the first and second embodiments, a color printer using yellow, cyan, and magenta inks has been described as an example of a thermal transfer serial printer. However, the present invention is not limited to this. Instead, for example, the present invention may be applied to a monochrome printer using only black ink. The thermal transfer method is not limited to the sublimation type thermal transfer, but may be a fusion type thermal transfer.

In the first and second embodiments, the description has been made of the example of the thermal transfer serial printer in which the thermal transfer recording head is mounted on the carriage. However, the present invention is not limited to this. A thermal recording serial printer in which a head is mounted on a carriage may be used. In the thermal recording serial printer 59, the head section 62 includes a thermal head 62a and light sources 62b and 62c for optical fixing.
, A density measuring sensor 21 and a carriage 19 on which these are mounted. This thermal recording serial printer is described in detail, for example, in Japanese Patent Application Laid-Open No. 5-124352. In addition, as the recording paper 10,
A thermosensitive recording paper in which yellow, cyan and magenta thermosensitive coloring layers are formed on a support is used.

In this example, the thermal head 1 is first synchronized with the forward movement of the head section 62 based on the image signals for one row.
8 is driven. Thus, the first line of the yellow image is color-recorded on the recording paper 10. Next, in synchronization with the backward movement of the head section 62, the density of the yellow image of one line recorded during the forward movement is measured. As described above, when the difference between the measured density and the predicted density is within a certain value, the head unit 62 is moved forward again and the yellow fixing light source 62b
Is emitted to light-fix the yellow image.

If the image is blurred, the head unit 62 is moved forward and the repair recording is performed by the thermal head 62a. During this return, the concentration is measured. If the repair recording is complete, the head section 62 is moved forward to fix the yellow image. Next, after the head portion 62 is moved back as it is, one line of the magenta image is recorded.

Even when recording a magenta image, if the difference between the measured density and the predicted density is within a certain value, the light source 62c for magenta fixing is made to emit light, and the magenta image is light-fixed. Make a magenta repair record. The same applies to the recording of a cyan image. Note that the cyan thermosensitive coloring layer was not given light fixing properties.

As an example of the thermal recording serial printer, a color printer using thermal recording paper having thermal coloring layers of yellow, cyan and magenta is shown.
However, the present invention is not limited to this, and may be applied to a monochrome printer using a thermosensitive recording paper that develops only black.

In each of the above examples, a thermal serial printer is used. However, as shown in FIG. 11, an ink jet serial printer having an ink jet recording head mounted on a carriage may be used. In the inkjet serial printer 65, the head unit 66 includes an inkjet recording head 67 that performs recording by discharging ink, the density measurement sensor 21, and the carriage 19 on which these are mounted. The ink jet recording head 67 includes ink tanks 68, 69, 70 filled with yellow, magenta, and cyan inks, and ink tanks 68, 6.
9 and 70 connected to three types of ink nozzle groups (not shown). Each ink nozzle group includes a plurality of ink nozzles arranged in the main scanning direction, and records a plurality of lines simultaneously. The density measurement sensor 21 measures ink dots on a plurality of lines.

In the above example, when recording one line sequentially in the three color lines of yellow, magenta, and cyan, the density measurement is performed after recording for each color.
When the recording for one line of yellow, magenta, and cyan is completed for all three colors, the density is measured, and the density is compared with the predicted density.
And a repair record.

In the first and second embodiments, the measured density of each portion printed on the recording material is obtained, and when the measured density does not reach the predicted density, the recording head is moved to the portion having a density difference. By driving and performing correction recording according to the density difference, a method of restoring fading and uneven density of an image generated on a recording material and a serial printer using the same have been described as examples. It is not limited. Hereinafter, a third embodiment of the present invention will be described. In the third embodiment, a method for preventing a line, which is more serious than a blur or density unevenness, from printing out in white in image recording by a serial printer, and a serial printer using the same will be described. I do. The same parts as those in the above-described first and second embodiments are denoted by the same reference numerals, and detailed description is omitted.

The thermal transfer serial printer to which this embodiment is applied is shown in FIGS. 1 and 2, and the ink ribbon 23 used for this is shown in FIG.
The carriage 1 of the thermal transfer serial printer 1
As shown in FIG. 4, the density measurement sensor 21 attached to the camera 9 is used to correct the measured density measured by the density measurement sensor 21 for blurring and uneven density as in the first and second embodiments. The heating element 34 incorporated in the thermal head 18 is not used for
a, 34b, 34c, 34d, 34e, 34f (see FIG. 6) are used to determine whether or not a failure has occurred.
In the present embodiment, for convenience of explanation, the heating elements 34a, 34b, 34c, 34d, 34e, 34f are used.
No. in order from the top in the figure. The numbers 1, 2, 3, 4, 5, 6 are assigned.

As shown in FIG. 12, a test recording area 10b for forming a test pattern is formed on the side of the image recording area 10a on the recording paper 10 used in the thermal transfer serial printer of this embodiment. Image recording area 1
At 0a, an image is recorded based on the image data as in the first and second embodiments. The test patterns 72, 73, and 74 for cyan, magenta, and yellow are recorded in the test recording area 10b after the image of six lines is recorded in the image recording area 10a. The positions where the test patterns 72, 73 and 74 are recorded are on an extension of the positions of the first six lines recorded in the image recording area 10a.

FIG. 12 shows the cyan test pattern 72 in an enlarged manner, and the test pattern line 7 is formed by the heating elements 34a to 34f.
2a to 72f are respectively recorded at a constant density. Then, magenta and yellow test patterns 73 and 74
Similarly, each of the heating elements 34a to 34f is caused to generate heat, and the corresponding test pattern line is recorded.

FIG. 13 schematically shows the electrical configuration of a thermal transfer serial printer to which this embodiment is applied. The system controller 16 is connected to a failure determination unit 75, a conveyance amount adjustment unit 76, and a recording line adjustment unit 77, in addition to those described in the first embodiment. Density measurement sensor 2
The signal output from the first light receiving sensor 48 is
Perform a logarithmic conversion and a complementary color conversion, thereby converting to a pseudo density of yellow, magenta, and cyan.

The density from the conversion section 58 is sent to the failure determination section 75 as an actually measured density. Then, the failure determination unit 75 reads the preset minimum density, compares the minimum density with the measured density for each color and for each pixel, and when the measured density does not reach the minimum density, It is determined that a failure has occurred in the heating element (any of 34a to 34f) in which is recorded. The above-mentioned minimum density is assumed to be a density in a state where image recording becomes impossible due to a failure such as disconnection or rupture of the heating elements 34a to 34f. This is a constant value set by the characteristics. Then, the failure determination unit 75 includes the heating elements 34a to 34a determined to be failure heating elements.
The number of 34f (any one of Nos. 1 to 6) is sent to the conveyance amount adjusting unit 76 and the recording line adjusting unit 77.

The transport amount adjusting section 76 stores the transport pattern of the recording paper 10 in accordance with the number of the faulty heating element so that recording can be performed only with the valid non-faulty heating element. When the number of the faulty heating element is sent from, the transport pattern corresponding to the number is read and transmitted to the system controller 16. The system controller 16 changes the rotation amount of the transport roller pair 11 according to the transport pattern sent from the transport amount adjustment unit 76,
In some cases, the rotation of the pulse motor 14 is controlled via the motor driver 15 so as to change the rotation direction from the normal rotation direction to the reverse rotation direction or from the reverse rotation direction to the normal rotation direction.

In the recording line adjusting section 77, according to the number of the failed heating element, recording is performed on all or a part of the remaining effective heating elements, and the heating element not used for recording is stopped so as to stop. The driving pattern for controlling the driving of is stored. When the number of the faulty heating element is sent from the fault determination unit 75, the drive pattern corresponding to the number is read and transmitted to the system controller 16. The system controller 16 controls the thermal head 18 via the head control unit 54 so that printing is performed based on the drive pattern sent from the print line adjustment unit 77.

Next, the operation of the present embodiment will be described with reference to flowcharts shown in FIGS. 14 to 19 and explanatory diagrams shown in FIGS. FIGS. 20 to 25 show recording papers 1 recorded on the conveyance amount adjusting unit 76 and the recording line adjusting unit 77, respectively.
0 schematically shows a transport pattern of 0 and a driving pattern of the thermal head 18. In order to make the drawings easier to understand, in FIGS.
The amount of conveyance of the recording paper 10 is shown by changing the position of. For example, when the recording paper 10 is conveyed by one line in the main scanning direction, the position of the thermal head 18 is shown by returning the position of one line in the main scanning direction.

When a print instruction is issued from the operation unit 56, the system controller 16 reciprocates the thermal head 18 three times to record six lines in three color lines sequentially in the image recording area 10a shown in FIG. . At the same time,
In the test recording area 10b, each test pattern 72 of cyan, magenta, and yellow consisting of six lines of each color,
Record 73, 74.

Next, the density measuring sensor 21 is driven to obtain the actually measured densities of the test patterns 72, 73 and 74 recorded previously. Then, the measured density of the test pattern of each color and each line is converted into a signal via the conversion unit 58 and transmitted to the failure determination unit 75. Then, the failure determination unit 75 compares the measured density with the minimum density. If any one of the measured densities of each color and each line does not reach the minimum density, the heating element (34a To 34f) are determined to be faulty heating elements, and their numbers (any of Nos. 1 to 6) are transmitted to the transport amount adjustment unit 76 and the recording line adjustment unit 77. If all the measured densities exceed the minimum densities, it is determined that none of the heating elements 34a to 34f is faulty, and in the recording for the next six lines, the recording paper 10
Is carried out as usual, that is, the driving pattern of the thermal head, that is, the conveyance of six lines and the recording of six lines are repeated, and an image is recorded on the recording paper 10.

The number of the faulty heating element is indicated by
When sent to the recording line adjustment unit 77, the transport pattern of the recording paper 10 corresponding to this number and the thermal head 1
8 is read out and transmitted to the system controller 16. The system controller 16 controls the pulse motor 14 and the thermal head 18 according to the read transport pattern and drive pattern.

Hereinafter, no. The transport pattern and the drive pattern when any one of the heating elements 1 to 6 is a faulty heating element will be described for each number. FIG.
As shown in FIG. When the one heating element 34a is a faulty heating element, the first line 80a that should have been recorded by the faulty heating element 34a among the first six lines recorded in the image recording area 10a becomes white. It is in a closed state (hereinafter, simply referred to as a blank line). Then, the pulse motor 14 is rotated in the reverse direction, and the recording paper 10
Is transported in the reverse direction by one line. Thereby, No. The two heat generating elements 34b are adjusted to the positions of the above-described blank lines 80a. Then, the thermal head 18 is driven and The second heating element 34b is caused to generate heat, and the white line 8
The image is recorded at 0a.

When the recording of the six lines of the first line is completed by the recording on the blank line 80a, the seventh line 80
In order to perform recording after g, the pulse motor 14 is rotated forward to carry forward six lines in the forward direction. In the second and subsequent rows, No. The heating element 34a of No. 1 is stopped. 2
The heating elements 34b to 34f of the recording paper 10
Record the image in In the third and subsequent rows, the conveyance of five lines and the recording of five lines by the five heating elements 34b to 34f are repeated, and the image is recorded in the entire image recording area 10a. Then, after the image is recorded, the fact that there is a failure in the heating element is displayed externally to urge the user to replace parts of the thermal head. In addition, No. described later. Two
Similarly, when any one of the six heating elements is a faulty heating element, the fact that the heating element has a failure is displayed to the outside when the image recording is completed.

In the third and subsequent lines, one line is composed of five lines. In this case as well, a test print is made on the test recording area 10b and the density is measured. If a further failure occurs in the heating element during printing, the blank line is reprinted using the effective heating element, and then the recording paper 10 is conveyed by the number of continuous effective heating elements. Printing while continuing. No. 2 to 6 heating elements 3
The same applies to 4b to 34f.

No. When the second heating element 34b is a faulty heating element, as shown in FIG. 21, the second line 80b of the image recording area 10a that should have been recorded by the heating element 34b becomes a blank line. The recording paper 10 is conveyed by one line in the forward direction. In the heating element 34a of No. 1, the blank line 80 b is The seventh heating line 34f records the seventh line 80g. From the eighth line 80h onward, No. The heating elements 34a and 34b of the Nos. 1 and 2 are stopped. The 3 to 6 heating elements 34c to 34f are caused to generate heat, and transport for 4 lines and recording for 4 lines are repeated.

No. When the third heating element 34c is a faulty heating element, as shown in FIG.
c becomes a blank line. The recording paper 10 is conveyed by two lines in the forward direction. In the heating element 34a of No. 1, the blank line 80 c is 7, 8 with the heating elements 34e, f of 5, 6
Record the second lines 80g and h, respectively. From the ninth line 80i onward, No. 1-3 heating elements 34a-
No. 34c is stopped. 4 to 6 heating elements 34d to 34f
Is generated, and conveyance for three lines and recording for three lines are repeated.

No. In the case where the fourth heating element 34d is a faulty heating element, as shown in FIG.
d becomes a blank line. The recording paper 10 is conveyed by two lines in the forward direction. No. 2 heating element 34b is used to draw a blank line. The seventh and eighth lines 80g and 80h are recorded by the fifth and sixth heating elements 34e and 34f, respectively. From the ninth line 80i onward, No. The heating elements 34d to 34f of Nos. 4 to 6 are stopped, and The heating elements 34a to 34c of the first to third heating elements are caused to generate heat, and the conveyance for three lines and the recording for three lines are repeated.

No. When the fifth heating element 34e is a faulty heating element, as shown in FIG.
e becomes a blank line. The recording paper 10 is conveyed by one line in the forward direction. No. 4, a blank line was formed by the heating element 34d of No. 4; 6th heating element 34f, 7th line 80g
Are recorded. After the eighth line 80h, N
o. The heating elements 34e and 34f of Nos. 5 and 6 are stopped. 1
The four heating elements 34a to 34d are caused to generate heat, and transport for four lines and recording for four lines are repeated.

No. When the heating element 34f of No. 6 is a faulty heating element, as shown in FIG.
f is a blank line. In the sixth and subsequent lines 80f, which are the blank lines, No. 6 heating elements 3
4f is stopped. By causing the heating elements 34a to 34e to generate heat, conveyance of five lines and recording of five lines are repeated.

In the third embodiment, the test recording area 10b is provided on the side of the image recording area 10a, and the test pattern 72 of each color is placed on an extension of the position corresponding to six lines recorded in the image recording area 10a. The present embodiment is not limited to this, and the test recording area 10b is replaced with the image recording area 10a as shown in FIG.
The test pattern 7 is provided at a position
After recording 2 g, 73 g, and 74 g, the recording paper 10 for the test recording area 10 b is conveyed to the image recording area 10 b.
The recording to a may be started. In this case, since the image recording area 10a can be widened in the width direction of the recording paper 10, the recording paper 10 can be used effectively. In this case, since printing is performed after the test print, a blank line does not occur. Therefore, the print of the image recording area 10a is, for example, No. If the heating element 34a of No. 1 is out of order, No. 2-No. Using the six heating elements 34b to 34f, printing is performed intermittently for five lines.

In the third embodiment, a thermal transfer serial printer is described as an example. However, in the present embodiment, as in the first and second embodiments,
The present invention may be applied to a thermal recording serial printer as shown in FIG. 10, or may be applied to an ink jet serial printer as shown in FIG. In the case of an ink-jet serial printer, it is not the heating element but the plurality of ink nozzles arranged in the main scanning direction that determine the failure. The density of the test pattern recorded by the ink nozzles is measured, and a failure such as nozzle clogging is determined based on whether the density reaches a preset minimum density.

In the third embodiment, an example is described in which only one of the heating elements arranged in the main scanning direction fails, but the present invention is not limited to this, and a plurality of heating elements are arranged. If the heating element fails, for example, even if two out of the six heating elements are determined to be faulty heating elements,
Similarly to the above example, a blank line is recorded in any of the remaining four heating elements, and for the remaining lines,
The conveyance amount of the recording paper 10 is adjusted, and recording is performed by the same number of heating elements as the number of lines of the conveyance amount.

The number of recording lines after the restoration of a blank line is
This corresponds to the maximum value of the number of consecutive effective recording elements. If the recording element at the end fails, the continuous number is only one. If the intermediate recording element fails, the continuous number is two. For example, if the second print element fails, the continuous numbers are “1” and “4”, respectively, so that four lines are conveyed using four print elements. If two heating elements fail, the maximum number of continuous heating elements is three.

In the third embodiment, when there is no failure in the printing element, printing and transporting are repeated by printing a predetermined number of lines and feeding the paper at the same distance as the predetermined number of lines. However, in a serial printer, since a paper feed amount is likely to be uneven, a streak-shaped gap may be generated between adjacent lines. Therefore, as in the serial printing method described in JP-A-7-125288,
By setting the paper feed amount for a line smaller than the predetermined number and overlapping and recording the lines at the ends of adjacent lines, it is possible to prevent the generation of a gap between the lines. in this case,
The overlapping lines may be recorded, for example, at a density of 50% of the density based on the image data, and by overlapping them, the lines may be recorded at a density of 100%.

Further, in the method in which recording is performed by overlapping lines, when a failure occurs in a recording element, first, the failed recording element records a recording element for recording an end of a row or another line. It is determined whether the element is a recording element. Then, the position of the line to be recorded by the failed recording element is adjusted to the position of another valid recording element, and if the failed recording element is a recording element for recording the end of a row, recording is performed at 50% density. If the element is a recording element for recording other lines, recording is performed at a density of 100%. Thereafter, the printing is continued with the consecutively arranged effective recording elements, and the paper feed amount is obtained by subtracting the number of overlapping lines from the number of the consecutively arranged effective recording elements. The lines recorded by the recording elements located at the ends of the effective recording elements arranged in a row are overlapped. The number of overlapping lines is not limited to one line, and a plurality of lines may overlap.

In the first, second and third embodiments,
Although a serial printing method for correcting printing defects such as blurring or white lines during printing and a serial printer using the same have been described as examples, the present invention is not limited to this. Hereinafter, a fourth embodiment of the present invention will be described. In the fourth embodiment, after printing is completed once, the recording paper is discharged to the outside, the recorded recording paper is reloaded, and a portion where a printing failure occurs among the recorded portions is performed. A serial printing method for correcting and recording the above and a serial printer using the same will be described. The same components as those in the first, second, and third embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

The thermal transfer serial printer to which this embodiment is applied is shown in FIGS. 1 and 2, and the ink ribbon 23 used for this is shown in FIG.
As the density measuring sensor 21 attached to the carriage 19, the one shown in FIG. 4 is used, and this density measuring sensor 21 is reloaded as shown in FIG. It is also used for detecting the image recording area 82a of the recorded recording paper 82.

As shown in FIG. 27, the image recording
The recording area 82a has a width Wp and a length Lp.
The four corners of the image recording area 82a₁, A_Two,
A_Three, A _FourTo correct the defective printing part.
This end point A₁~ A_FourAre used. Heh
The moving range in which the scanning unit 22 reciprocates in the sub-scanning direction depends on the image recording.
It is set longer than the width Wp of the recording area 82a. This
This is because even if the recording paper 82 is conveyed in an inclined state, the image
Correction of printing failure to the entire recording area 82a
To do that.

FIG. 28 schematically shows the electrical configuration of a thermal transfer serial printer to which the present embodiment is applied. An image recording area recognizing unit 85 and a corrected image data creating unit 86 are connected to the system controller 16 in addition to those described in the first embodiment. The concentration measurement sensor 21
Reference points B ₁ , B ₂ , B ₃ , B ₄ , B ₅ , on the boundary between the image recording area 82a and the surrounding margin 82b.
The coordinates of B ₆ , B ₇ , and B ₈ are detected and transmitted to the image recording area recognition unit 85. The image recording area recognition unit 85 calculates the coordinates of the end points A _{1 to} A ₄ from the coordinates of the reference points B _{1 to} B ₈ , and transmits the position information of the image recording area 82 a to the corrected image data creation unit 86. The correction image data creation unit 86
In accordance with the position information of the image recording area 82a transmitted from the image recording area recognizing unit 85, the position information of the image data read from the image processing unit 51 is corrected to create corrected image data.

The corrected image data generated by the corrected image data generator 86 is transmitted to the density estimator 59. The density predicting section 59 obtains the density of each pixel in the image recording area as the predicted density based on the corrected image data.

Next, the operation of the fourth embodiment will be described.
This will be described with reference to the flowchart in FIG. Cereal
In the printer 1, the recorded recording paper 82 is reloaded.
When a correction print instruction is issued from the operation unit 56, the
The recording paper 82 is conveyed toward the head unit 22 and the reference point B
₁~ B₈Is detected. Reference point B₁~ B₈of
In reading, first, the arrow X₁At the position where it passes
Head so that the position of the degree measurement sensor 21 can be adjusted.
22 is moved. Arrow X₁, X_TwoIs the main scanning direction M
The image recording areas 82 are parallel and kept at a certain distance from each other.
It is set to be located near the center with respect to the width Wp of a.
ing. Then, the recording paper 82 is moved in the normal rotation direction in the main scanning direction M.
Is transported to the density measuring sensor 21, the arrow X₁Along
To read the density of the recording paper 82. And the preset
The image recording area 8 is determined based on whether or not the set reference density has been reached.
2a or its surrounding margin 82b,
It is located on the boundary between the image recording area 82a and the margin 82b.
Reference point B₁, B _TwoAre sequentially detected.
Reference point B₁, B_TwoFollowing the detection of_TwoIn the position
The position of the degree measurement sensor 21 is adjusted, and the recording paper 82 is mainly
When transported in the reverse direction to the scanning direction, the reference
B_Three, B_FourAre detected.

[0095] Then the recording sheet 82 is conveyed in the reverse direction so as to be fit the position of the concentration measuring sensor 21 in a position to pass through the arrow Y _1. Arrows Y ₁ and Y ₂ are in the sub-scanning direction S
Are parallel to each other and are kept at a constant interval from each other.
It is set to be located near the center with respect to the length Lp of 2a. When the head 22 moves from the left side to the right side of the recording paper 82 in the drawing, the density measurement sensor 2
1 reads the density of the recording paper 82 along the arrow Y _1,
Reference points B ₅ and B ₆ are detected. Following the detection of the reference points B ₅ and B ₆ , the position of the density measurement sensor 21 is adjusted to the position of the arrow Y ₂ , and the head 22 moves from the right side to the left side of the recording paper 82 in FIG. At reference points B ₇ and B
_Eight coordinates are detected. The coordinates of the reference points B _{1 to} B ₈ thus detected are transmitted to the image recording area recognition unit 85.

The image recording area recognizing unit 85 determines whether the reference point B₁
~ B₈From the coordinates of the four corners A₁~ A_FourCalculate the coordinates of
You. Below, for convenience, the reference point B₁~ B₈The coordinates of
(B_1x, B _1y)-(B_8x, B_8y), Endpoint A₁~ A_FourSeat
Mark (A_1x, A_1y) ~ (A_4x, A_4y). Below
Is the end point A₁Coordinates (A_1x, A_1yHow to calculate
Will be described. Reference point B₁, B_FourIs a straight line, Y = m₁X + n₁... (1) where m₁= (B_4y-B_1y) / (B_4x-B_1x) N₁= B_1y-((B_4y-B_1y) / (B_4x-B_1x)) B_1x And the reference point B_Five, B₈Is a straight line, Y = m_TwoX + n_Two... (2) where m_Two= (B_8y-B_5y) / (B_8x-B_5x) N_Two= B_5y-((B_8y-B_5y) / (B_8x-B_5x)) B_5x It is represented by Endpoint A₁Is represented by the above equations (1) and (2).
(X,
Y) = (A_1x, A_1y), A_1y= M₁(A_1x) + N₁... (3) A_1y= M_Two(A_1x) + N_Two(4) From these equations (3) and (4), the end point A₁Coordinates (A_1x,
A_1y) Is determined as follows. A_1x= (N_Two-N₁) / (M₁-M_Two) A_1y= M₁(N_Two-N₁) / (M₁-M_Two) + N₁ Where m₁= (B_4y-B_1y) / (B_4x-B_1x) N₁= B_1y-((B_4y-B_1y) / (B_4x-B_1x)) B_1x m_Two= (B_8y-B_5y) / (B_8x-B_5x) N_Two= B_5y-((B_8y-B_5y) / (B_8x-B_5x)) B_5x Hereinafter, the end point A_Two~ A_FourCoordinates (A_2x, A_2y) ~ (A_4x,
A_4y), The reference point B₁, B_FourEquation of a straight line passing through
Reference point B_Two, B_Three, The reference point B_Five, B₈Pass through
Formula, reference point B₆, B₇From the formula that passes through
You. In this way, the end point A₁~ A_FourCoordinates (A_1x, A
_1y) ~ (A_4x, A_4yImage recognized by asking for
The position information of the image recording area 82a is the corrected image data creation unit.
86. The recording paper 82 and the head 22
Is returned to the initial position.

When the position information of the image recording area 82a is transmitted from the image recording area recognizing means, the corrected image data creating section 86 receives the position information of the image recording area 82a in the main scanning direction and the sub-scanning direction with respect to the normal image recording area used for normal recording. Corrected image data is created by tilting and moving the position information of the image data read from the image processing unit 51 in accordance with the position shift and the tilt. The corrected image data is sent to the density prediction unit 59, and the predicted density for each color is calculated for each pixel. After calculating the predicted density, the recording paper 82 is conveyed toward the head unit 22, drives the density measurement sensor 21, moves the head unit 22, and synchronizes with the movement to record the recording paper 8.
Read the measured density of 2. If the difference between the measured density and the predicted density is within a certain value, it is determined that the density is in an appropriate range.

If the measured density is smaller than the predicted density and the difference exceeds a certain value, the system controller 16 determines that the density is insufficient and corrects the photographic data corresponding to the insufficient for each pixel. Then, the print head 22 is moved in the direction opposite to the previous direction, and in synchronization with this movement, the thermal head 18 is driven based on the corrected print data to perform corrected print recording according to the density shortage. If the concentration is correct,
Or, if the density shortage is corrected by the corrected print record,
The recording paper 82 is conveyed, and the density measurement for the next one line and the correction print recording are performed. The same applies to the image recording area 82
Corrected print recording is performed over the entire area of a. In this way, the blurring or unevenness of the image formed on the recording paper 82 is corrected, and a clear image can be obtained.

In the fourth embodiment, in order to recognize the position information of the image recording area 82a, the coordinates of _eight reference points B _{1 to} B ₈ are read, and the coordinates of the reference points B _{1 to} B ₈ are used. End points A _{1 to} A ₄ of the four corners of the image recording area 82a
However, the present invention is not limited to this. For example, before performing correction printing, the entire area of the recording paper 82 is pre-scanned with a coarse resolution, and the image recording area 82a is obtained from the data obtained by pre-scanning the entire area. it may be obtained coordinates of the end points a ₁ to a ₄ of the four corners.

[0100]

As described above, according to the present invention,
Measure the density of the recorded dots, compare the obtained measured density with the predicted density, and if blurring or uneven density occurs in the image, re-record so as to repair it,
An image having an appropriate density can be recorded. Further, since the repair recording is performed, it is possible to prevent waste of recording material such as recording paper and ink and waste of time.

Further, in the serial printing method according to the ninth aspect, when a failure recording element which cannot be recorded due to a failure among the plurality of recording elements is detected, the recording head is moved again to record the failure recording element. Since a line to be originally recorded is recorded by another recording element, it is possible to prevent a state in which an image line becomes white. Further, printing is performed using the effective printing element from the next line, so that printing can be continued even if a part of the printing element has a failure.

Further, in the serial printing method according to the present invention, after an image is once recorded on the recording material, the recorded recording material is loaded again, and printing failure occurs in each of the recorded lines. Line is corrected and recorded for that line, so it is discharged once,
The recorded recording material is also corrected, and an image having an appropriate density can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a thermal transfer serial printer of the present invention.

FIG. 2 is a sectional view of a main part showing a head unit.

FIG. 3 is a plan view showing an ink ribbon.

FIG. 4 is a schematic diagram showing a concentration measurement sensor.

FIG. 5 is a block diagram illustrating a control unit of the thermal transfer serial printer of FIG. 1;

FIG. 6 is an explanatory diagram showing a recording state of an image.

FIG. 7 is a flowchart showing a print sequence of the thermal transfer serial printer shown in FIG.

FIG. 8 is a cross-sectional view of a principal part showing a head unit provided with a density measurement sensor on both sides of a thermal head.

FIG. 9 is a flowchart showing a print sequence of the embodiment shown in FIG.

FIG. 10 is a schematic diagram showing a thermal recording serial printer.

FIG. 11 is a schematic view showing an ink jet serial printer.

FIG. 12 is a front view showing a recording sheet used in a third embodiment of the present invention.

FIG. 13 is a block diagram illustrating a control unit of a serial printer to which a third embodiment of the present invention is applied.

FIG. 14 is a flowchart showing a print sequence of the embodiment shown in FIG.

FIG. 15 is a flowchart of the processing shown in FIG.
It is a continued flowchart when it becomes 2.

FIG. 16 is a flowchart of FIG.
It is a continued flowchart in case it became 3.

FIG. 17 is a flowchart of FIG.
It is a continued flowchart when it becomes 4.

FIG. 18 is a flowchart of the processing shown in FIG.
It is a continued flowchart when it becomes 5.

FIG. 19 is a flow chart shown in FIG.
It is a continued flowchart when it becomes 6.

FIG. 20 is a diagram showing the configuration of the third embodiment of the present invention. 1
FIG. 4 is an explanatory diagram showing a recording paper transport pattern and a thermal head drive pattern when the heating element of FIG.

FIG. 21 is a diagram showing the configuration of the third embodiment of the present invention. 2
FIG. 4 is an explanatory diagram showing a recording paper transport pattern and a thermal head drive pattern when the heating element of FIG.

FIG. 22 is a diagram showing the configuration of the third embodiment of the present invention. 3
FIG. 4 is an explanatory diagram showing a recording paper transport pattern and a thermal head drive pattern when the heating element of FIG.

FIG. 23 is a diagram showing the configuration of the third embodiment of the present invention. 4
FIG. 4 is an explanatory diagram showing a recording paper transport pattern and a thermal head drive pattern when the heating element of FIG.

FIG. 24 is a diagram showing the configuration of the third embodiment of the present invention. 5
FIG. 4 is an explanatory diagram showing a recording paper transport pattern and a thermal head drive pattern when the heating element of FIG.

FIG. 25 is a diagram illustrating the configuration of the third embodiment of the present invention. 6
FIG. 4 is an explanatory diagram showing a recording paper transport pattern and a thermal head drive pattern when the heating element of FIG.

FIG. 26 is a front view showing a recording sheet used in another embodiment, which is different from that shown in FIG.

FIG. 27 is an explanatory diagram illustrating a state when a recording sheet on which an image is recorded is reloaded in the fourth embodiment of the present invention.

FIG. 28 is a block diagram illustrating a control unit of a serial printer to which the fourth embodiment of the present invention is applied.

FIG. 29 is a flowchart when performing correction print recording in the fourth embodiment of the present invention.

[Description of Signs] 1, 59, 65 Serial printer 10, 82 Recording paper 10a, 82a Image recording area 16 System controller 18, 61 Thermal head 19 Carriage 21 Density measurement sensor 22, 60, 66 Head unit 23 Ink ribbon 24 Cassette 41 Illumination unit 42 Light receiving unit 67 Inkjet recording head 75 Failure determination unit 76 Transport amount adjustment unit 77 Recording line adjustment unit 85 Image recording area recognition unit 86 Corrected image data creation unit

Claims (16)

[Claims] 1. A serial printing method for performing recording while moving a recording head on a recording material, wherein when a printing failure occurs on a recorded line, correction recording is performed on the line. Serial printing method. 2. The recording material is a thermosensitive recording paper having a thermosensitive coloring layer, and the recording head is a thermal head that heats the thermosensitive coloring layer to color-record an image. 1. The serial printing method according to 1. 3. The recording head according to claim 1, wherein the recording head is a thermal head for recording an image by transferring ink melted or sublimated by heating an ink ribbon from behind to a surface of a recording material. Serial printing method. 4. The serial printing method according to claim 1, wherein the recording head is an ink jet recording head that records an image on a recording material by discharging ink. 5. A carriage that reciprocates in a sub-scanning direction that is a width direction of a recording material, and a recording head that is held by the carriage and records a predetermined number of lines on the recording material according to image data during the forward movement. In a serial printer comprising: a density measuring means attached to the carriage, for measuring the respective portions recorded during the forward movement of the carriage to determine an actual measured density while the carriage is moving back, A density estimating unit that obtains a density to be recorded in each part from image data as a predicted density, comparing the measured density with the predicted density for each part, and when the measured density does not reach the predicted density, Calculating means for calculating the density difference; and when there is a portion having the density difference, the carriage is reciprocated again, and the portion having the density difference during the forward movement is converted to the density difference. And a correction recording unit for performing correction recording by driving the recording head, and when there is no portion having the density difference, the recording material is moved in the main scanning direction in order to record the next predetermined number of lines on the recording material. And a recording material conveying means for conveying the recording material to the serial printer. 6. A carriage reciprocating in a sub-scanning direction which is a width direction of a recording material, and a carriage held by the carriage,
A serial printer having a recording head that records a predetermined number of lines on a recording material in accordance with image data during the movement, one of which is located on both sides of the recording head and one is selected according to a moving direction of the carriage, First and second density measuring means for measuring each part immediately after recording to obtain an actual measured density; density predicting means for obtaining a density to be recorded in each part as a predicted density from image data; Computing means for comparing the density and the predicted density for each part, and calculating the density difference when the measured density does not reach the predicted density, and re-moving the carriage when there is a part having the density difference Moving the recording head for the portion having the density difference during the movement, and driving the recording head in accordance with the density difference to perform correction recording; and when the portion having the density difference does not exist, To record the next predetermined number of lines on a recording material, a serial printer, wherein the recording material conveying means, that the provided for conveying the recording material in the main scanning direction. 7. The apparatus according to claim 5, wherein the density measuring unit includes a light projecting unit for illuminating each recorded portion, and a light receiving unit for converting the reflected light into an electric signal. Serial printer. 8. The serial printer according to claim 5, wherein each part is one pixel. 9. A serial printing method for moving a recording head having a plurality of recording elements arranged in a main scanning direction in a sub-scanning direction and recording a predetermined number of lines on a recording material in accordance with image data during the movement. When a faulty recording element that cannot be recorded due to a failure is detected among the plurality of recording elements, the recording head is moved again, and a line to be originally recorded by the faulty recording element is set to another effective recording. A serial printing method characterized by recording by an element. 10. A carriage that reciprocates in a sub-scanning direction that is a width direction of a recording material, and is held by the carriage,
A plurality of recording elements are arranged in the main scanning direction, and a recording head that records a predetermined number of lines on the recording material by the recording elements while the carriage is moving linearly, and a conveying unit that conveys the recording material in the main scanning direction. A serial printer equipped with a density measuring unit attached to the carriage, for measuring each line on which recording is performed by a recording head, and for obtaining an actually measured density; When there is no recording element, the recording element on which the line is recorded is determined to be a failure recording element, and failure determination means is provided. When all of the M recording elements arranged in the main scanning direction are valid, the recording material is provided for each of M lines. When the failure determination unit determines that the recording element has failed, the recording material is transported by at least one line in the main scanning direction, and is divided into the failed recording element. Driving the recording element and sub-scanning the carriage so that the applied line is recorded by an effective recording element, and then recording is continued while conveying the recording material in the main scanning direction according to the number of the effective recording elements. And a control unit for controlling reciprocation in the direction and conveyance of the recording material in the main scanning direction. 11. When the number of continuously arranged effective printing elements is N, printing is performed by N effective printing elements while conveying the printing material in the main scanning direction by N lines. The serial printer according to claim 10. 12. A carriage reciprocating in a sub-scanning direction which is a width direction of a recording material, and a carriage held by the carriage,
A plurality of recording elements are arranged in the main scanning direction, and a recording head that records a predetermined number of lines on the recording material by the recording elements while the carriage is moving linearly, and a conveying unit that conveys the recording material in the main scanning direction. A serial printer equipped with a density measuring unit attached to the carriage, for measuring each line on which recording is performed by a recording head, and for obtaining an actually measured density; When there is no recording element, the recording element on which the line has been recorded is determined to be a failure recording element. Failure determination means. When all of the M recording elements arranged in the main scanning direction are valid, the (MA) line While the recording material is conveyed every minute, recording is performed by overlapping the A line at a time, and when the failure determination unit determines that the recording element has failed, the recording material is transferred by at least one line. Convey in the scanning direction, record the line allocated to the failed recording element with an effective recording element, and then continue recording while conveying the recording material in the main scanning direction according to the number of effective recording elements. And a control means for controlling the driving of the recording element, the reciprocation of the carriage in the sub-scanning direction, and the conveyance of the recording material in the main scanning direction. 13. Assuming that the number of consecutively arranged effective printing elements is N, the printing material is conveyed in the main scanning direction by (N−A) lines, and is overlapped by A lines to be N pieces. 13. The serial printer according to claim 12, wherein recording is performed by an effective recording element. 14. A serial printing method for performing recording while moving a recording head on a recording material, wherein an image is recorded once on the recording material, and then the recorded recording material is loaded again, and each recorded line is recorded. A serial printing method for correcting and recording a line in which a printing failure has occurred. 15. A carriage reciprocating in a sub-scanning direction which is a width direction of a recording material, and a carriage held by the carriage,
A serial printer including a recording head that records a predetermined number of lines on the recording material in accordance with image data during the movement, and a transport unit that transports the recording material in the main scanning direction, wherein the recorded recording material is loaded Image recording area recognizing means for recognizing position information of an image recording area in which an image is recorded, a main scanning direction and a sub-scanning direction of the position information of the image recording area and position information based on the image data. A corrected image data generating means for calculating a positional shift and a tilt of the image data, tilting the image data in accordance with the positional shift and the tilt, and generating corrected image data by moving the corrected image data; and After the image recording area is recognized, the carriage is moved, and during the movement of the carriage, each part of the image recording area is measured, and Density measuring means for obtaining a density; density predicting means for obtaining a density to be recorded in each part in the image recording area as a predicted density based on the corrected image data; and the measured density and the predicted density. Is calculated for each part, and when the measured density does not reach the predicted density, a calculating means for obtaining the density difference; and when there is a part having the density difference, the carriage is moved again, and And a correction recording means for driving a recording head in accordance with the density difference to perform correction recording on a portion having a density difference therein. 16. The image recording area recognizing means performs the movement of the carriage and the conveyance of the recording material by the conveying means. During the movement and the conveyance, a part where an image is formed and a part around the part are formed. 16. A serial printer according to claim 15, wherein a boundary line between the image recording area and the image recording area is recognized by the density measuring means.