KR930008444B1 - Paper feeding device - Google Patents

Abstract

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Description

Paper feeder

1A to 1F are diagrams showing the position of a sheet of paper shifted in a conventional label printer.

2 is a structural diagram of a label printer according to an embodiment of the present invention.

3 is a control circuit display diagram of the label printer shown in FIG.

4 and 5 are flowcharts showing the operation of the label printer shown in FIG.

6a to 6f show the position of the paper moved in the label printer shown in FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed apparatus for a printer, and more particularly, to a paper feed apparatus which retracts paper and sets it at a printing start position.

There is a label printer which conventionally prints label data on continuous paper and cuts and separates the print portion to generate one label. In this label printer, the print head prints the label data on the paper, and the cutter cuts the paper supplied from the print head to separate the print portions corresponding to a single label. When the paper is cut, the leading edge of the remaining paper is set at the cutter position. For this reason, if the gap between the print head and cutter is relatively large, the label printer moves the paper backward for the next printing process after cutting the paper so that the printing head starts to face the inner part slightly separated from the leading edge of the paper. Set the paper in position.

Here, the description of the conveyance of this sheet will be described in more detail with reference to FIGS. 1A to 1F. The paper is set so that its tip protrudes from the cutter position through the print head position as shown in FIG. 1A first. When the cutter cuts the paper as shown in Fig. 1b, the remaining paper retreats at the cutter position by a distance X1 slightly smaller than the distance D between the cutter and the printhead, and the printhead is at the leading end as shown in Fig.1. Is set at the print start position opposite to the inner portion of the paper spaced by the distance D-X1 at. Thereafter, the paper advances again at the printing start position and is processed by the printing head while moving by a distance X2 corresponding to the number of printing lines. When this printing process is completed, this sheet is advanced again by a distance (X1 + P-X2) so that the cutter is set at the sheet cutting position so that the cutter faces the portion of the sheet corresponding to the rear end of the label (where P is the length of the label). Display). When the cutter cuts the paper, the remaining paper is retracted from the cutter position by the distance X1 again as shown in FIG. 1F for the next printing process and set at the printing start position.

The sheet is then moved forward or backward by the platen, and the platen is driven by the stepping motor. The rotational direction and the rotational angle of this stepping motor are controlled by numerical data determined according to the moving direction and the moving distance of the paper. In the label printer, when the paper is retracted in preparation for the printing process, even if the stepping motor is properly driven, the paper does not retreat by the distance X1 due to slip between the platen and the paper, for example, and the paper is moved from the printing start position. It is often set in the position which shifted. This slip is likely to occur, especially when the platen begins to rotate. The shift of the printing start position is cumulatively increased when the retraction operation of the sheet is repeated to issue a plurality of labels. That is, the conventional label printer did not have complete precision in paper transport.

An object of the present invention is to provide a paper conveying apparatus which can reduce an error in paper conveying.

This purpose is provided between a paper passage, a stepping motor, a paper feed mechanism driven by the stepping motor to move the paper along the passage, and a predetermined position and a printing processing position on the passage to a printing processing position at a predetermined position. The paper sensor detects the leading edge of the retracted paper toward the paper, and the stepping motor is rotated in the retracting direction, and when the paper sensor detects the leading edge of the paper, the stepping motor is rotated again by a predetermined angle to print the desired portion of the paper. This is achieved by a paper conveying apparatus having a control circuit set at the processing position.

In this paper feed apparatus, when the paper sensor detects the leading end of the paper retreating from the predetermined position toward the printing processing position, the control circuit rotates the stepping motor again by a predetermined angle to set the desired portion of the paper at the printing processing position. Since the position of the sensor is closer to the printing processing position than the predetermined position, the rotation angle of the stepping motor is less vertically determined based on the position of the sensor than when determined based on the predetermined position. The desired portion can be set at the second predetermined position.

Next, a label printer according to an embodiment of the present invention will be described with reference to FIGS. 2 to 6f. The label printer prints the label data on the continuous label paper, and then peels off the print portion from the sheet to issue one label. When a plurality of label sheets are completely peeled off from the site, the label printer prints the label data on the label sheet and peels the label sheet from the sheet again to issue a single label.

2 shows the structure of this label printer. The label printer has a print head 1, a platen 2, a cutter 3, an optical sensor 4, a peeling plate 5 and a stepping motor 6. The print head 1 is provided at a position opposite to the platen 2 and holds a plurality of print elements which can be lined up in the axial direction of the platen 2. These printing elements print label data on a label sheet line by line. For example, when thermal paper is used as the label paper, the print head 1 is composed of a thermal head. The label paper is first supplied to the printing head 1, and a predetermined amount is conveyed for each printing process of the single-factor line. The platen 2 is driven by the stepping motor 6 and moves the label sheet along the passage PT indicated by the broken line in FIG. The label paper advances when the stepping motor 6 is rotated counterclockwise, and retreats when the stepping motor 6 is rotated clockwise. The cutter 3 is installed relatively spaced in the print head 1, cuts the label paper supplied after printing in the print head 1, and separates the print portion of the label paper as a single label. The optical sensor 4 and the release plate 5 are provided between the print head 1 and the cutter 3. When the label sheet is adhered to the sheet, the peeling plate 5 is used to peel the label sheet from the sheet, and the optical sensor 4 is cut by the cutter 3 to print the next label data. It is used to detect the leading edge of the retracted paper. The optical sensor 4 is also used to detect the tip of the label sheet peeled off the sheet when the label sheet is adhered to the sheet. The optical sensor 4 shown in FIG. 2 is a light transmission sensor composed of a light emitting portion and a light receiving portion. In this case, the light emitting portion and the light receiving portion are disposed to face each other with the passage PT of the sheet interposed therebetween. The optical sensor 4 can be changed to, for example, a light reflecting sensor according to the type of paper.

3 shows a control circuit for this label printer. This control circuit has a CPU 10, a ROM 11, a RAM 12, and an I / O interface 13 interconnected by a bus line BS. The I / O interface 13 has a drive circuit 20 of the print head 1, a drive circuit 21 of the cutter 3, a drive circuit 22 of the stepping motor 6, an input unit 23 and an optical sensor. (4) is connected. The CPU 10 controls various operations such as printing of label data, movement of label sheets, cutting of label sheets, and the like. The ROM 11 stores the control program of the CPU 10 and other fixed data, and the RAM 12 temporarily stores the input / output data of the CPU 10. The driving circuit 20 receives label data supplied from the CPU 10 through the I / O interface 13, supplies the label data to the print head 1 in units of print lines, and print head 1. The print element of is selectively driven corresponding to the label data of each print line. The drive circuit 21 receives the cutting signal of the paper supplied from the CUP 10 via the I / O interface 13 and operates the cutter 3. The drive circuit 22 receives the numerical data supplied from the CPU 10 via the I / O interface 13 as the control data and drives the stepping motor 6 to rotate by the direction and angle corresponding to the numerical data. do. The rotation angle of the stepping motor 6 is designated as the number of drive pulses supplied from the drive circuit 22 to the stepping motor 6. The stepping motor 6 rotates one step, that is, a predetermined angle in response to each driving pulse supplied from the driving circuit 22. The optical sensor 4 generates a detection signal when detecting the leading edge of the paper. This detection signal is supplied from the optical sensor 4 to the CPU 10 via the I / O interface 13. The input unit 23 holds various input keys and connection ports of an external computer for inputting data necessary for generating label data and a start command for issuing a label, and inputs input signals through the I / O interface 13 to the CPU 10. Is supplied.

Next, the operation of this label printer will be described with reference to FIGS. 4 and 5. FIG.

When the power of the label printer is turned on, the CPU 10 starts the operation shown in FIG. 4 in accordance with the control program stored in the ROM 11. When this operation is started, various circuit elements such as a RAM, for example, are initialized at step S1, and at step S2, it is checked whether the start command for label issuance has been input at the input unit 23. If a start instruction for label issuance has not been input, another processing proceeds to step S3. Then step S2 is executed again. Other processes include, for example, the preparation of label data and the label issuance process in the case where the label sheet is adhered to the sheet.

When it is detected that a command to start issuing a label is input, in step S4, the label data is printed for one line on a label sheet whose tip is set at the position ST shown in FIG. It is checked whether all label data corresponding to the label of is printed. When it is detected that all the label data is not printed, the paper is transferred in a predetermined amount corresponding to the interval of the printing line in step S6, and when the printing of the label data ends again, steps S5, S6, and S4 are repeatedly executed. When the printing of all the label data corresponding to one label is finished, the paper is transferred again in step S7 so that the portion of the paper corresponding to the rear end of the label is set to the position of the cutter 3, and the step ( In S8) the paper is cut by the cutter 3, whereby the printing portion of the paper is independently issued as a label. The leading edge of the remaining sheets is then at the position of the cutter 3. In the subsequent step S9, the tip is set at the position ST and the sheet is conveyed in the reverse direction to the print start position where the print start portion slightly inward from the tip faces the print head 1. In this process, the stepping motor 6 firstly rotates the leading edge of the paper in the retraction direction beyond the position of the sensor 4 at the position of the cutter 3, and again the leading edge of the paper is positioned at the position of the sensor 4. When it reaches, it rotates by the angle of the number of steps necessary to retract the printing start portion of the paper to the position of the printing head 1 (in detail, the position of the printing element) on the basis of the position of this sensor 4. . In this way, when the sheet is set at the print start position in preparation for the print processing of the label to be generated next, it is checked whether or not all the required number of labels have been issued in step S10. When it is detected that all of the label issuances have been completed, step S2 is executed again. If the one-sided label is not finished, steps S4-S10 are executed again and the remaining labels are issued.

FIG. 5 shows the printing preparation process shown in FIG. 4 at step S9 in detail. In this process, first, the first numerical data is set in the motor driver 22 in step S20. This first numerical data determines to specify the rotation direction and the rotation angle of the stepping motor 6 which are necessary to retract the paper longer than the distance between the position of the cutter 3 and the position of the sensor 4. It became. Rotation of the Stepping Motor 6 When the stepping motor 6 is set in the motor driver 22 and rotated corresponding to the first numerical data, the platen 2 retracts the paper. In step S21, it is checked whether or not the optical sensor 4 has detected the leading edge of the sheet to be retracted in this way. This step S21 is repeatedly executed while the leading edge of the sheet is not detected. When the leading edge of the sheet reaches the position of the optical sensor 4, it is detected in step S21 and step S22 is executed. In this step S22, the first numerical data which have been previously set is subjected to a Kinssel, and the second numerical data is set in the motor driver 22 instead. The second numerical data is determined so as to designate the rotation direction and the rotation angle of the stepping motor 6 necessary for retracting the sheet of paper, which is equal to the distance between the position of the sensor 4 and the position ST (except the sheet of paper). If the time delay cannot be neglected after the tip of? Reaches the position of the sensor 4 and the second numerical data is set in the motor driver 22, the rotation angle designated by the second numerical data is Decreases in correspondence with the amount of movement of the paper in the middle). The stepping motor 6 does not stop in changing the numerical data but rotates again by an angle corresponding to the second numerical data set in the motor driver 22 to retract the sheet to the printing start position. At this time, the leading end of the paper is set at the position ST, and the printing start portion of the paper slightly spaced from this leading end is set at the position of the printing head 1.

6A to 6F are paper position display diagrams showing the position of the sheet to be moved in the label printer shown in FIG. When the start command for label is input and the printing processing of the label data is started, the paper advances at the print start position set at the position ST where the distance X1 is separated from the cutter position as shown in FIG. 6A. . This sheet advances by the distance X2 during the printing process of the label data, and reaches the position shown in Fig. 6B when the printing process is completed. This next sheet is advanced by the distance (X1 + P-X2) shown in FIG. 6C, and the portion of the sheet corresponding to the rear end of one label is set to the cutter position. The cutter 3 shown in FIG. 2 then cuts the paper at the cutter position as shown in FIG. 6d, and sets the remaining paper leading edge at the cutter position. This sheet is retracted for subsequent printing. When the leading edge of the paper is retracted by the distance X3 equal to the distance between the cutter position and the sensor position as shown in FIG. 6E, the sensor 4 installed at the optical sensor position detects the leading edge of the paper, and then Then, the stepping motor 6 shown in FIG. 2 is rotated again by a predetermined angle, and the paper is retracted again by the distance (X1-X3) shown in FIG. 6F to set at the printing start position.

As described above, in the present embodiment, the printing of the paper is finished, the paper is transported by a predetermined distance (X1 + P-X2), and the cutter 3 installed at the cutter position is vibrated to cut the paper and issue the label. When the next sheet of paper is conveyed in the reverse direction and the leading edge of the sheet is detected by the sensor 4 installed at the sensor position, the sheet of paper is again moved to the printing start position in this direction based on the numerical data by the distance (X1-X3). Set it.

Therefore, if the distance X3 between the cutter position and the sensor position is made relatively large, the sensor 4 installed at the sensor position detects the leading edge of the paper and the paper is conveyed backward based on the numerical data until the paper is set at the printing start position. The travel distance (X1-X3) is very small.

In this way, the distance fed back to the numerical data can be shortened. Therefore, even if some deviation occurs in the movement distance, no deviation is caused that the printing by the printing head 1 causes a problem. Furthermore, even if there is a deviation due to the paper feed for cutting the paper, the reverse feed distance to the sensor 4 is mechanically determined by the installation position of the sensor 4, so that the distance (X1-X3) Deviations from transfer do not accumulate on every label issue. In other words, the deviation of the printing start position is a slight deviation that always causes a backfeed performed once based on the numerical data determined based on the position of the sensor 4. Therefore, when a plurality of labels are issued, the printing area of the label data is prevented from being distributed for each label.

Moreover, although the above-mentioned embodiment applies the present invention to a label printer, the present invention is not limited to this embodiment. That is, the present invention can be applied to other printers in which paper is conveyed and set at the printing start position. For example, in a printer in which repeated printing processing is performed using different color printing ribbons set between the printing head and paper, the paper is fed back to the printing start position each time the printing processing of each color is finished. do. The present invention also applies to such a printer.

Further, in the above embodiment, the first and second numerical data are set in the driving circuit 22 in the paper conveying operation, but a single numerical data may be set in the driving circuit 22. In this case, the driving circuit 22 repeatedly supplies the driving pulses to the stepping motor 6, counts the number of driving pulses supplied to the stepping motor 6 from the time when the sensor 4 detects the leading edge of the paper. It is configured to stop the supply of the drive pulse when the count value reaches the value determined by this numerical data.

Claims (2)

A paper passage (PT) and a stepping motor (6), a paper feed mechanism (12) driven by the stepping motor (6) to move the paper along the passage (PT), and a predetermined portion on the passage (PT). A paper sensor 4 disposed between the position and the print processing position to detect the leading edge of the paper retracting from the predetermined position toward the print processing position, and the stepping motor 6 rotated in the retracting direction, And a control means (10) for rotating the stepping motor (6) by a predetermined angle when the paper sensor (4) detects the leading edge of the paper to set a desired portion of the paper at the printing processing position. Paper feeder. The paper conveying apparatus according to claim 1, wherein the predetermined position is a cutting processing position for cutting apart the printing portion of the paper from the remaining portion.

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