JP3207344B2 - Serial dot printer and its operation control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial dot printer such as a thermal transfer type, an ink jet type or a wire dot type and a method of controlling the operation thereof. The present invention relates to a serial dot printer mounted thereon and an operation control method thereof.

[0002]

2. Description of the Related Art Conventionally, a predetermined print medium has been sandwiched between a transport roller and a pressure roller which is pressed against the transport roller and transported between a platen and a thermal head. In this state, the carriage is moved, and while the ink ribbon of the ribbon cassette is being wound, a heating element formed on the thermal head is energized based on a desired print signal, and the heating element is heated. A thermal transfer printer that performs desired printing on the print medium by melting the ink of the ink ribbon and transferring the melted ink to paper has been widely used.

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 conveyed between the carriage and the platen. , A predetermined amount of transporting operation is performed, and then a series of operations of performing printing for the next scan are repeated to complete printing for one page.

In such a thermal transfer printer, when printing only characters, even if there is a variation in the transport amount of the printing medium, it is not so noticeable and does not significantly affect the printing result. When printing the image of (1), there is a variation in the transport amount of the print medium, and if there is an overlap in the printing for each scan, the overlapping portion becomes a black streak and if there is a gap between each scan. However, there was a problem that the gap became noticeable as a white streak.

For this reason, a thermal transfer printer that prints graphics or the like requires extremely high-precision transport. In recent thermal transfer printers, the amount of rotation of the outer periphery of a transport roller is detected, and a predetermined amount of rotation is always obtained. By controlling the rotation amount of the motor of the transport roller so as to rotate the transport roller, accurate transport is performed.
Then, in order to consider the eccentricity of the transport roller, it is necessary to measure the rotation amount for one line feed in advance and correct it as the transport amount at each rotation angle. A plurality of markers are attached to the sensor, and the sensor detects and counts the markers to detect the rotation amount of the transport roller, and controls the rotation amount of the transport motor so that the transport roller always rotates by a predetermined rotation amount. It is supposed to.

[0006]

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

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and enables proper conveyance control of a print medium to be performed, thereby obtaining a good print result without black or white stripes even when printing a graphic image. It is an object of the present invention to provide a thermal transfer printer capable of performing the following.

[0008]

According to a first aspect of the present invention, there is provided a method for controlling operation of a serial type dot printer, comprising: a print head having a plurality of printing elements arranged for printing; An image scanner having a plurality of detectors arranged in a line is arranged so as to be reciprocally movable in the same direction, and a transport roller formed so that the entire circumference is N times a predetermined line feed amount (N is an integer). A method for controlling the operation of a serial type dot printer, wherein a marker provided at one place on the outer periphery of the transport roller is used as a print start initial position with respect to a print medium by the print head before printing starts. Printing is performed, then a line feed of the one line feed amount is performed, and then a test pattern printing is performed again by the print head, and thereafter, the test pattern is printed by the image scanner. The interval between line feeds between the previous test pattern printing and the current test pattern printing is measured, and a correction value of the transport amount of the print medium is calculated N times based on the measured interval value. The correction transport amount for the entire circumference is stored, and thereafter, printing is performed by transporting the print medium with the marker as an initial position for starting printing in accordance with the corrected transport amount.

According to the operation control method of the serial type dot printer of the present invention, the printing medium is conveyed in accordance with an appropriate correction conveyance amount with reference to one marker, so that the white stripe is obtained regardless of any printing information. Good printing results without black streaks can be obtained.

[0010] The invention described in claim 2 is the same as the claim 1.
3. The method for controlling the operation of a serial dot printer according to claim 1, wherein the test pattern printing is performed using at least a printing element arranged at the top and a printing element arranged at the bottom of the print head.

According to the operation control method of the serial type dot printer of the present invention, the print position of the lowermost print element of the print head printed at the time of the previous test pattern printing and the print position printed at the time of the current test pattern printing By reading the interval between the print position of the uppermost print element of the head and the print position by the image scanner, extremely accurate transport control of the print medium can be performed, and a high-quality image can be obtained.

According to a third aspect of the present invention, there is provided a serial dot printer for performing the method according to the first aspect, wherein a marker serving as an initial position for starting printing is provided at one position on the outer periphery of the transport roller. And the arrangement length of the detection elements of the image scanner is longer than the arrangement length of the printing elements of the print head.

According to the serial dot printer of the present invention, one marker provided on the outer periphery of the transport roller is set at the initial position of the start of printing, and the detection of the image scanner longer than the array length of the print elements of the print head is detected. By using the array length of the elements, the interval between line feeds between the previous test pattern printing and the current test pattern printing can be measured, and an appropriate correction value for the transport amount can be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 a serial dot printer according to the present invention is applied. A flat platen 2 extending in a longitudinal direction is provided on a frame 1 of the printer. A carriage shaft 3 located in front of the platen 2 and extending in parallel with the platen 2 is supported between both side surfaces of the frame 1. A carriage 4 is attached to the carriage shaft 3 so as to be able to reciprocate along the carriage shaft 3. A thermal head 5 as a print head is provided at the tip of the carriage 4 so as to face the platen 2. Are attached so as to be able to freely move in and out. An ink ribbon (not shown) is accommodated 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 sending out the ink ribbon are provided respectively.

In this embodiment, as shown in FIGS. 1 and 2, an image scanner 9 is provided on one side (the left side in the figure) of the carriage 4. As shown in FIG. 3, an opening 10 is formed on a surface of the image scanner 9 facing the platen 2.
Two light-emitting members 1 such as lamps are provided inside the image scanner 9 and on both sides of the opening 10.
The image scanner 9 receives reflected light of light emitted from the light-emitting member 11 to the document, and forms a predetermined image inside the image scanner 9. An image sensor unit 12 for reading is provided.

In the present embodiment, the arrangement length of the detection elements of the image scanner is formed longer than the arrangement length of the print elements of the print head. This image scanner 9
The positional relationship between the thermal head 5 and the print head will be further described with reference to FIG. In the present embodiment, the position of the uppermost heating element 5 a of the thermal head 5 is above the image scanner 9. Is set to be the same as the position of the sixth detection element 9a.

Also, below one end of the frame 1,
A carriage driving motor 13 is disposed such that an output shaft of the carriage driving motor 13 penetrates the upper surface of the frame 1. A driving pulley 14, which is rotationally driven by the carriage driving motor 13, is provided on the output shaft of the carriage driving motor 13. Are arranged. A driven pulley 15 is rotatably disposed on the upper surface of the other end of the frame 1, and a part thereof is connected to the lower surface of the carriage 4 between the driving pulley 14 and the driven pulley 15. The carriage drive belt 16 is stretched. Then, by driving the carriage drive motor 13 to rotate and 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.

As shown in FIG. 4, a transport roller 17 for transporting a predetermined print medium at a predetermined speed is provided below the rear portion of the platen 2. As shown in FIG. 5, the length of the outer circumference of the transport roller 17 is set to N times the line feed amount, and only one marker 18 is formed on the outer circumference of the transport roller 17. A sensor 19 for detecting the marker 18 is provided near the transport roller 17.

Further, below the transport roller 17,
A plurality of pressing rollers 20 pressed against the transport roller 17
Are rotatably arranged. Further, the frame 1
A paper feeder (not shown) is arranged behind the paper feeder. The paper feeder accommodates, for example, a reading medium such as a document, a printing medium such as a normal printing sheet, and a stencil printing sheet. It has been made. By rotating the transport roller 17, a document and a print medium supplied from the paper feeding device between the transport roller 17 and the pressure roller 20 are transported between the thermal head 5 and the platen 2. It has been made to be. further,
Above the platen 2, a paper discharge roller 21 for guiding a print medium after printing is provided.

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

FIG. 7 shows a schematic electrical configuration of the thermal transfer printer. The thermal transfer printer is C
The CPU 23 is controlled by a PU 23. The CPU 23 includes a ROM 24 storing printing conditions and the like suitable for each type of printing medium to be used, and a RAM 25 storing various data and the like.

Print data is sent to the CPU 23 from an input device such as a computer via an interface. 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 a thermal head drive circuit, and drives the heating element 5a of the thermal head 5 according to the print information. Further, the CPU 23 sends 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 from / to the print medium, a carriage drive circuit for controlling the movement of the carriage 4, and a print medium. A control signal is sent to a transfer motor control circuit or the like for controlling the transfer motor.

In the thermal transfer printer having the above-described configuration, when printing is performed, first, test printing is performed in order to obtain a correction value of the transport 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 feeder is set at the print start position. At this time, the position at which the marker 18 is detected by the sensor 19 is set as the initial position at which the conveyance roller 17 starts printing. Then, a test pattern printing start signal is output from the CPU 23 to the thermal head driving circuit, and the thermal head 5 is driven, so that test pattern printing based on predetermined image data is performed. Thereafter, a line feed of a predetermined line feed amount is performed, and the test pattern is printed again. Thereafter, the gap in the line feed is measured by the image scanner 9, a predetermined amount of line feed is corrected, and the corrected line feed amount (the number of drive steps of the transport motor) is stored.

That is, the positional relationship between the image scanner 9 and the thermal head 5 is such that the position of the uppermost printing element 5a of the thermal head 5 is the same as that of the sixth detector element 9a from the top of the image scanner 9 as described above. Position, and among the detection elements 9a of the image scanner 9 disposed downstream of the thermal head 5 in the printing direction, the detection elements 9a up to the fifth from the top,
The interval between the dots at the lowermost dot of the first test pattern printing and the uppermost dot of the test pattern printing printed immediately before is measured. For example, when a white streak is present in the gap, a correction is made to reduce the number of drive steps of the transport motor so that the transport amount is reduced by an amount corresponding to the measured gap amount, and the correction is performed. The transfer amount is stored in the CPU 23. If there is an overlap in the second test pattern, a correction to increase the carry amount is performed.

At this time, by setting the lowermost dot and the uppermost dot so as to overlap with each other, an image without white stripes can be obtained. In addition, by performing processing such that 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, a good image without white and black stripes is obtained. Image is obtained.

Then, a new line is printed again and a test pattern is printed, and a corrected line feed amount is obtained in the same manner. This is N
The number of times of the 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 the line feed amounts in one rotation of the transport roller 17 are stored.

Since the transport roller 17 returns to the initial position of the transport roller 17 by one rotation, a drive step of a transport motor (not shown) for driving the transport roller by the corrected transport amount obtained by the test pattern printing. By controlling the number and repeating the line feed at the time of printing, good printing without white or black stripes 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. In this embodiment, a case where a thermal transfer printer is used has been described. However, a serial dot printer may be used. For example, the present 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 according to the present invention need only control the motor of the transport roller based on the correction value of the transport of the print medium once stored. It is not necessary to complicate the invention, and since only one marker is formed on the transport roller, it is possible to carry out appropriate transport control of the print medium at a low cost in terms of cost. Printing results can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing a 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. 1;

FIG. 5 is an explanatory diagram illustrating 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 print element of a print head.

FIG. 7 is an explanatory diagram illustrating an electrical schematic configuration of the 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 Transport Roller 20 Pressure Roller

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-8-90862 (JP, A) JP-A-8-2032 (JP, A) JP-A-4-176675 (JP, A) JP-A-8-90 85242 (JP, A) JP-A-1-288457 (JP, A) JP-A-4-313869 (JP, A) JP-A-5-96796 (JP, A) JP-A-8-187911 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 19/96 B41J 2/51

Claims (3)

(57) [Claims] 1. A print head in which a plurality of printing elements for performing printing are arranged and arranged, and an image scanner in which a plurality of detection elements for performing image reading are arranged and arranged are reciprocally movable in the same direction. To a predetermined one line feed amount of N
A method for controlling the operation of a serial dot printer in which a doubled (N is an integer) transport roller is provided, wherein a marker provided at one location on the outer periphery of the transport roller is set at the beginning of printing before printing starts. As a position, a test pattern is printed on the print medium by the print head, then a line feed of the one line feed amount is performed, then a test pattern print is performed again by the print head, and then the previous test pattern print is performed by the image scanner. The interval between the line feed and the current test pattern printing is measured, and the correction value of the transport amount of the print medium is calculated N times based on the measured interval value. After that, the marker is set as the initial position of the printing start according to the corrected transport amount, and Operation control method of serial type dot printer and performing printing by performing transmission. 2. The operation of a serial dot printer according to claim 1, wherein the test pattern printing is performed using at least a printing element arranged at the top of the print head and a printing element arranged at the bottom. Control method. 3. A serial dot printer for performing the method according to claim 1, wherein a marker which is an initial position for starting printing is provided at one position on the outer periphery of the conveying roller, and a detecting element of the image scanner is provided. Wherein the array length is longer than the array length of the print elements of the print head.