JPH09156178A - Serial dot printer and operation control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a high quality image by determining the correction amount of a print medium predetermined number of times repeatedly and storing the corrected feeding amount for the entire circumference of a feed roller and then printing a marker at the initial position of starting print according to the corrected feeding amount thereby controlling the feeding of print medium accurately. SOLUTION: When power is turned on and a print medium is fed, while being separated, from the paper feeder of a printer and set at a print start position, a sensor 19 detects a marker 18 and sets an initial position of a feed roller 17 for starting the printing operation. A CPU 23 then delivers a signal for starting the printing of a test pattern to a thermal head drive circuit 26 thus driving a thermal head. After a test pattern is printed based on a predetermined image data, a predetermined amount of line feed is performed before printing a test pattern again. Subsequently, the space between the lines is measured by means of an image scanner and the predetermined amount of line feed is corrected and the corrected line feed amount is stored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer type, ink jet type, wire dot type, etc. serial type dot printer and its operation control method, and more particularly to a print head as a printing means and an image scanner as a reading means. The present invention relates to a mounted serial dot printer and an operation control method thereof.

[0002]

2. Description of the Related Art Conventionally, a predetermined print medium is sandwiched between a transport roller and a pressure contact roller which is in pressure contact with the transport roller, and the print medium is transported between a platen and a thermal head. A predetermined pressure contact force, the carriage is moved in this state, and while the ink ribbon of the ribbon cassette is being wound, the heating element formed on the thermal head is energized based on a desired print signal to heat the heating element. Then, a thermal transfer printer is often used in which the ink of the ink ribbon is melted and transferred to a sheet to perform desired printing on the print medium.

In such a thermal transfer printer, first, printing is performed for one scan while the carriage is moved along the platen while a predetermined print medium is being conveyed between the carriage and the platen. After a predetermined amount of printing has been performed, a conveying operation of a predetermined amount is performed, and then a series of operations of performing printing for the next scan is repeated to complete printing for one page.

In such a thermal transfer printer, when printing only characters, even if there is variation in the amount of print medium conveyed, it is not very noticeable and does not significantly affect the printing result, but graphics, etc. In the case of printing the image, if there is variation in the conveyance amount of the print medium and there is an overlap in the print for each scan, the overlapped portion becomes a black streak and there is a gap between each scan. , There was a problem that the gap became a white streak and became conspicuous.

Therefore, a thermal transfer printer for printing graphics or the like is required to be transported with extremely high accuracy. In recent thermal transfer printers, the amount of rotation of the outer periphery of the transport roller is detected, and only a predetermined amount of rotation is constantly detected. By controlling the rotation amount of the motor of the carrying roller so as to rotate the carrying roller, accurate carrying is performed.
In order to consider the eccentricity of the carrying roller, it is necessary to measure the rotation amount for one line feed in advance and correct it as the carrying amount at each rotation angle. By attaching multiple markers with the sensor, the sensor detects this marker and counts it to detect the rotation amount of the transport roller, and controls the rotation amount of the transport motor so that the transport roller is always rotated by a predetermined rotation amount. It is supposed to do.

[0006]

However, for that purpose, it is necessary to constantly detect and count the marker formed on the outer periphery of the conveying roller by the sensor, which complicates the control of the thermal transfer printer and reduces the cost. However, there was a problem that it was expensive.

The present invention has been made in view of the above-mentioned points, and it is possible to perform proper conveyance control of a print medium, and to obtain a good print result without black streaks or white streaks even when printing a graphic image. It is an object of the present invention to provide a thermal transfer printer capable of performing the above.

[0008]

In order to achieve the above object, an operation control method for a serial type dot printer according to a first aspect of the present invention is a print head in which a plurality of print elements for printing are aligned, and an image reading. An image scanner in which a plurality of detecting elements for performing the above are arranged so as to be reciprocally movable in the same direction, and a conveying roller formed to have a total circumferential length N times a predetermined line feed amount (N is an integer). A method for controlling the operation of a serial dot printer provided, wherein a marker provided at one position on the outer circumference of the conveying roller is used as an initial position for starting printing before the printing is started, and a test pattern is printed on the printing medium by the printing head. Printing is performed, then the line feed of the one line feed amount is performed, the test pattern is printed again by the print head, and then the image scanner is used. The line feed interval between the previous test pattern print and the current test pattern print is measured, and the correction value of the carry amount of the print medium is obtained based on the measured interval value. It is characterized in that the corrected carry amount for the entire circumference is stored, and thereafter the print medium is carried with the marker as the initial position for starting printing according to the corrected carry amount for printing.

According to the operation control method of the serial type dot printer of the present invention, the print medium is carried in accordance with an appropriate corrected carry amount with one marker as a reference. It is possible to obtain a good print result without black streaks.

[0010] The invention described in claim 2 is the same as the claim 1.
The operation control method for a serial type dot printer described in (4) above is characterized in that the test pattern printing is performed using at least the print elements arranged in the highest position and the print elements arranged in the lowest position of the print head.

According to the operation control method of the serial type dot printer of the present invention, the printing position of the lowest print element of the print head printed at the time of the last test pattern printing and the printing at the time of the test pattern printing this time. By reading the distance from the print position of the uppermost print element of the head with the image scanner, it is possible to perform extremely accurate conveyance control of the print medium and obtain a high-quality image.

According to a third aspect of the present invention, there is provided a serial type dot printer which performs the method according to the first aspect, wherein a marker which is an initial position for starting printing is provided at one position on the outer circumference of the conveying roller. In addition, the array length of the detection elements of the image scanner is longer than the array length of the print elements of the print head.

According to the serial type dot printer of the present invention, one marker provided on the outer circumference of the conveying roller is set at the initial position for starting printing, and the image scanner which is longer than the array length of the print elements of the print head is detected. By using the array length portion of the element, the line feed interval between the previous test pattern printing and the current test pattern printing can be measured to obtain an appropriate correction value for the carry amount.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an explanatory view showing a schematic main structure of a thermal transfer printer to which the serial type dot printer of the present invention is applied. A frame 1 of the printer has a platen 2 having a flat plate shape extending in the longitudinal direction. A carriage shaft 3 that is located in front of the platen 2 and extends parallel to the platen 2 is supported between both side surfaces of the frame 1. A carriage 4 is reciprocally attached to the carriage shaft 3 along the carriage shaft 3, and a thermal head 5 as a print head is provided at the tip of the carriage 4 so as to face the platen 2. Is attached so that it can be moved in and out freely. An ink ribbon (not shown) is housed on the upper surface of the carriage 4, and a ribbon cassette 6 for guiding the ink ribbon between the thermal head 5 and the platen 2 is detachably mounted. Further, a winding bobbin 7 for winding the ink ribbon of the ribbon cassette 6 and a delivery bobbin 8 for delivering the ink ribbon are provided.

In this embodiment, as shown in FIGS. 1 and 2, an image scanner 9 is arranged on one side of the carriage 4 (left side in the drawing). As shown in FIG. 3, an opening 10 is formed on the surface of the image scanner 9 facing the platen 2.
Further, inside the image scanner 9 and on both sides of the opening 10, two light emitting members 1 including a lamp and the like are provided.
1, 11 are arranged so as to be directed to the opening 10, and inside the image scanner 9, the reflected light of the light emitted from the light emitting member 11 to the document is received to form a predetermined image. An image sensor unit 12 for reading is provided.

In this embodiment, the array length of the detection elements of the image scanner is formed longer than the array length of the print elements of the print head. This image scanner 9
The positional relationship between the print head and the print head will be further described with reference to FIG. It is formed so as to be longer than the array length L2 in the normal conveying direction of a document or a print medium. In the present embodiment, the position of the uppermost heating element 5a of the thermal head 5 is above the image scanner 9. It is set so as to be at the same position as the sixth detection element 9a.

On the lower side of one end of the frame 1,
A carriage drive motor 13 is arranged such that its output shaft penetrates the upper surface of the frame 1. The output shaft of the carriage drive motor 13 has a drive pulley 14 rotatably driven by the carriage drive motor 13. Is provided. A driven pulley 15 is rotatably arranged on the upper surface of the other end of the frame 1, and a part of the driven pulley 15 is connected to the lower surface of the carriage 4 between the drive pulley 14 and the driven pulley 15. The carriage drive belt 16 is suspended. Then, the carriage drive motor 13 is rotationally driven to drive the carriage drive belt 16 via the drive pulley 14,
The carriage 4 is reciprocated along the carriage shaft 3 in parallel with the platen 2.

Further, as shown in FIG. 4, a conveying roller 17 for conveying a predetermined print medium at a predetermined speed is arranged below the rear portion of the platen 2. Further, as shown in FIG. 5, the length of the outer circumference of the carrying roller 17 is N times the line feed amount, and the outer circumference of the carrying roller 17 is provided with only one marker 18. A sensor 19 for detecting the marker 18 is arranged near the transport roller 17.

Further, below the conveying roller 17,
A plurality of pressure contact rollers 20 pressed against the transport roller 17.
Are rotatably arranged. Further, the frame 1
A sheet feeding device (not shown) is arranged in the rear of the sheet feeding device. The sheet feeding device accommodates, for example, a reading medium such as an original document and a printing medium such as normal printing paper and stencil printing paper. It is designed to be. Then, by rotating and driving the transport roller 17, the document and the print medium supplied from the paper feeding device between the transport roller 17 and the pressure contact roller 20 are transported between the thermal head 5 and the platen 2. It is designed to do. further,
Above the platen 2, a paper discharge roller 21 that guides the print medium after printing is arranged.

On one side of the platen 2 of the frame 1,
A positioning marker 22 is formed, and by reading the positioning marker 22 by the image scanner 9, the stop position of the carriage 4 is recognized.

FIG. 7 shows an electrical schematic construction of the thermal transfer printer. The thermal transfer printer is C
The CPU 23 is controlled by the PU 23. The CPU 23 is provided with a ROM 24 in which printing conditions suitable for each type of print medium used are stored, and a RAM 25 in which various data are stored.

Print data is sent to the CPU 23 from an input device such as a computer via an interface. Further, the image data read by the image scanner 9 is sent to the CPU 23 via an interface.

The CPU 23 sends print pattern information to the thermal head drive circuit, and the heating element 5a of the thermal head 5 is driven according to the print information. Further, from the CPU 23, a drive circuit of the image scanner 9, a drive circuit of a head up-down mechanism for pressing and separating the thermal head 5 to and from the print medium, a carriage drive circuit for controlling the movement of the carriage 4, and a print medium are sent. A control signal is sent to each of the transport motor control circuits for controlling the transport motors.

When printing is performed in the thermal transfer printer having the above-described configuration, first, test printing is performed in order to obtain a correction value for the carry amount of the print medium in the printer used for printing.

When the power of the printer is turned on, the print medium separated and fed from the paper feeding device is set at the print start position. At that time, the position where the marker 18 is detected by the sensor 19 is set as the initial position of the conveyance roller 17 for starting printing. Then, a test pattern printing start signal is output from the CPU 23 to the thermal head drive circuit, and the thermal head 5 is driven, so that test pattern printing based on predetermined image data is performed. After that, a predetermined line feed amount is applied and the test pattern is printed again. After that, the gap at the line feed is measured by the image scanner 9, the line feed amount is corrected by a predetermined amount, and the corrected line feed amount (the number of driving steps of the carry motor) is stored.

That is, regarding the positional relationship between the image scanner 9 and the thermal head 5, as described above, the position of the uppermost printing element 5a of the thermal head 5 is the same as that of the sixth detection element 9a from the top of the image scanner 9. Of the detection elements 9a of the image scanner 9 arranged downstream from the thermal head 5 in the printing direction, the fifth detection element 9a from the top causes
The dot interval between the bottommost dot of the first test pattern print and the topmost dot of the test pattern print printed immediately before is measured. For example, when there is a white streak in the gap, correction is performed to reduce the number of drive steps of the conveyance motor so as to reduce the conveyance amount by an amount corresponding to the measured gap amount, and the correction is performed. The carry amount is stored in the CPU 23. If there is an overlapping portion in the second test pattern, on the contrary, correction is performed to increase the carry amount.

At this time, by setting the dot at the lowermost end and the dot at the uppermost end to overlap with each other, an image without white streaks can be obtained. Also, the lowest dot of printing and the highest dot of printing of the next line are overlapped, and the print data of the overlapping portion is thinned out. Images can be obtained.

Then, the line feed is performed again and the test pattern is printed to obtain the corrected line feed in the same manner. This is N
The number of times of line feed, that is, the number of line feeds corresponding to the entire circumference of the transport roller 17, is repeated, and the corrected line feed amount at each line feed is stored. As a result, all line feed amounts for one rotation of the transport roller 17 are stored.

Since the carry roller 17 returns to the initial position of the carry roller 17 by making one rotation, a step of driving a carry motor (not shown) for driving the carry roller with the corrected carry amount obtained by this test pattern printing. By controlling the number and repeating the line feed at the time of printing, excellent printing without white or black lines can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made as necessary. For example, the positional relationship between the detection element 9a of the image scanner 9 and the heating element 5a of the thermal head 5 is not limited to the above example. Further, although the case where the thermal transfer printer is used has been described in the present embodiment, any serial dot printer may be used, and for example, the invention can be applied to an ink jet printer, a wire dot printer, and the like.

[0032]

As described above, the serial dot printer and the operation control method therefor according to the present invention can be controlled by controlling the motor of the carry roller based on the stored correction value of the carry of the print medium. There is no need to make it complicated, and since only one marker needs to be formed on the conveying roller, the cost can be reduced, and proper conveyance control of the print medium can be performed. The print result can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing the main configuration of a thermal transfer printer of the present invention.

FIG. 2 is a plan view of a carriage part of FIG. 1;

FIG. 3 is a plan view of an image scanner part of FIG. 1;

FIG. 4 is a left side view of FIG.

FIG. 5 is an explanatory diagram showing a positional relationship between a transport roller, a marker, and a sensor.

FIG. 6 is an explanatory diagram showing a positional relationship between a detection element of an image scanner and a printing element of a print head.

FIG. 7 is an explanatory diagram showing an electrical schematic configuration of a thermal transfer printer.

[Explanation of symbols]

 1 Frame 2 Platen 4 Carriage 5 Thermal Head 9 Image Scanner 11 Light Emitting Member 12 Image Sensor Unit 17 Conveying Roller 20 Pressing Roller

Claims (3)

[Claims] 1. A print head in which a plurality of print elements for printing are aligned and an image scanner in which a plurality of detection elements for reading an image are aligned are reciprocally movable in the same direction, and the entire circumference is provided. N for a predetermined line feed amount
A method for controlling the operation of a serial type dot printer in which a conveyance roller formed with a double number (N is an integer) is arranged, wherein a marker provided at one position on the outer periphery of the conveyance roller is set at an initial stage of printing start before printing is started. As a position, the test pattern is printed on the print medium by the print head, then the line feed of the one line feed amount is performed, and then the test pattern is printed by the print head again, and then the previous test pattern is printed by the image scanner. The correction feed amount in the entire circumference of the feed roller is measured by repeating N times to measure the line feed interval from the test pattern print this time and obtain the correction value of the feed amount of the print medium based on the value of the measured gap. Is stored, and thereafter, the marker is set as the initial position for starting printing according to the corrected carry amount. Operation control method of serial type dot printer and performing printing by performing transmission. 2. The operation of the serial dot printer according to claim 1, wherein the test pattern printing is performed by using at least the print elements arranged in the highest position and the print elements arranged in the lowest position of the print head. Control method. 3. A serial dot printer for performing the method according to claim 1, wherein a marker that is an initial position for starting printing is provided at one position on the outer circumference of the conveying roller, and a detection element of the image scanner. The serial dot printer is characterized in that the array length of is longer than the array length of the print elements of the print head.