JPH07121602B2 - Paper feed control method and paper feed control device for serial printer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed control method and a paper feed control device for a serial printer which performs a line feed along a sheet along a platen after a carriage centering operation at the time of line feed.

[0002]

2. Description of the Related Art Generally, a serial printer is provided with a carriage mechanism as shown in FIG. 5, for example. The carriage mechanism is provided with a platen 2 along which a sheet to be printed is placed, a guide shaft 4 is provided in parallel with the platen 2, and a carriage 6 is slidably provided on the guide shaft 4. ing.
That is, the guide shaft 4 constitutes a guide means for guiding the carriage 6 so that the carriage 6 can travel in parallel with the platen 2. A transparent and elastic paper guide 8 such as a synthetic resin plate is attached to the carriage 6, and
A print head 12 for printing from the print window 10 is mounted. The carriage 6 is connected to a step motor (not shown) by a rotation transmission means such as a belt, and travels along the guide shaft 4 in synchronization with the rotation operation of the step motor. A pair of arms 14 are rotatably attached to both ends of the guide shaft 4, and a bail roller shaft 18 having a bail roller 16 is attached between the arms 14 and 14. A pair of tension springs 20 are attached between the arm 14 and a frame (not shown), and the bail roller 16 together with the bail roller shaft 18 is attracted to the platen 2 side and pressed against a sheet (not shown) on the platen 2. And the paper guide 8 is
At the time of printing, the sheet is supported on the platen 2 from the printing surface side, and the leading end of the sheet is guided to the bail roller 16 side to prevent the platen 2 from bending.

When printing with such a printing mechanism, when the carriage 6 finishes printing at the left end or right end of the paper when printing on the leading edge of the paper and a line feed occurs, the slack occurs on the paper. Due to the difference between the left edge and the right edge of the slack, line feed defects such as skewed printing occur. In order to prevent such a line feed failure, after the printing of one line is completed, the carriage 6 is moved to a predetermined position and the center position of the paper at the time of line feed, and then the line feed is performed. That is, the centering operation of the carriage 6 is performed as a preparatory operation for performing a line feed operation. In this centering operation,
The centering position of the carriage 6 is set according to the size of paper that can be loaded. That is, the centering position is set to a position where the printable paper width does not deviate from the printable range of the paper regardless of the change of the paper width, that is, a position where the slack prevention effect of the paper can be assumed. There is.

[0004]

By the way, the setting of the centering position is performed by, for example, as shown in FIG.
When the print start position is N _{O in} the case of a wide paper 21A of a size or the like, the center of the paper 21A is the centering position N ₁ , but at this position, it is the right end of the A4 size paper 21B, and for width narrow sheet 21C such B5 size, since the centering position N ₁ deviates from the print range, set to a larger centering position N ₂ very error that can correspond to the sheet 21A having a width from the sheet width narrow sheet 21C It had been. Although such a centering position N ₂ is set within the printing range of the papers 21A, 21B, and 21C, the paper 21A has a deviation ΔL from the optimum centering position N ₁ .
When the carriage 6 is centered at the centering position N ₂ and printing is performed on the wide paper 21A, there is a risk of line feed failure such as skewed printing even if the centering operation is performed.

Therefore, the present invention sets the centering position suitable for the size of the paper to be printed on the basis of the print data, and prevents the line feed failure such as the oblique print and the paper feed control method and the paper feed control device of the serial printer. The purpose is to provide.

[0006]

In order to achieve the above object, a paper feed control method for a serial printer according to the present invention is provided.
A carriage (6) equipped with a print head (12) and a plurality of types of paper of different sizes (21A, 21B, 21C)
And a guide means (guide shaft 4) for guiding the carriage so that the carriage can run parallel to the platen, and a line feed is performed while the carriage is centered at the time of line feed. In the paper feed control method of the serial printer to be performed, the centering position to be set in the carriage is calculated from the print data,
After controlling the carriage to this centering position,
Characterized by a line break.

In order to achieve the above object, the paper feed control method for a serial printer according to the present invention has a carriage (6) having a print head (12) and a plurality of papers (21A, 21B, 21C) of different sizes. ) Is loaded and a guide means (guide shaft 4) for guiding the carriage so that the carriage can run parallel to the platen, and line feed is performed with the carriage being centered at the time of line feed. In the paper feed control method of the serial printer, whether the centering position to be set in the carriage should be calculated from the print data, and the centering position should be compared with the previous centering position stored in the storage means (RAM 26) and updated. If it is determined whether or not to change, the centering position of the storage means is updated. In addition, the carriage is controlled at the centering position to perform a line feed, and when the change should not be made, the centering position of the storage means is maintained and the carriage is controlled at the centering position to cause a line feed. It is characterized by performing.

Further, the paper feed control device for a serial printer of the present invention includes a carriage (6) having a print head (12) mounted thereon, a platen (2) having a plurality of papers of different sizes loaded therein, and the carriage. In a paper feed control device for a serial printer, which has a guide means (guide shaft 4) that guides the platen so that it can travel parallel to the platen, and performs line feed in a state where the carriage is centered at the time of line feed, centering of the carriage is performed. Storage means (RAM 26) for storing position information, calculation means (CPU 22) for calculating the centering position of the carriage from print data, and change for changing the centering position information stored in the storage means based on the calculation result. Means (CPU 22) and the center stored in the storage means Control means for centering operation of the carriage according ring position information (drive control circuit 3
4) and are included.

Further, the paper feed control device for a serial printer of the present invention includes a carriage (6) having a print head (12) mounted thereon, a platen (2) having a plurality of papers of different sizes loaded therein, and the carriage. In a paper feed control device for a serial printer, which has a guide means (guide shaft 4) that guides the platen so that it can travel parallel to the platen, and performs line feed in a state where the carriage is centered at the time of line feed, centering of the carriage is performed. A storage unit (RAM 26) for storing the position information, and a determination unit (CP) for determining whether to change the centering position information stored in the storage unit from the print data.
U22), and when the determination means determines that the centering position information should be changed, the changing means (CPU 22) for changing the centering position information described in the storage means and the storage means are stored in the storage means. And a control unit (drive control circuit 34) for performing the centering operation of the carriage according to the centering position information.

[0010]

According to the paper feed control method of the serial printer of the invention, the centering position of the carriage is determined from the horizontal print position of each line based on the prediction that the actual print position of each line will correspond to the paper to be printed. Then, after controlling the carriage to the centering position, a line feed operation is performed. That is, the centering position of the carriage is calculated from the printing position of each line on the paper, the carriage is controlled to this centering position, and then a line feed, that is, one line of paper is fed. According to such a paper feed control method, an appropriate centering position of the carriage is set from the print data, and printing defects such as skew printing are prevented.

Further, according to the paper feed control method for the serial printer of the present invention, the centering position of the carriage is calculated from the print width of each line, the centering position is stored in the storage means, and the previous centering stored in the storage means is calculated. The centering position change control is performed based on the comparison with the position. That is, the previous centering position stored in the storage means is compared with the centering position calculated from the print width of each line, and if the calculated centering position is larger, the centering position stored in the storage means is compared. The position is updated, the centering position is newly set, the carriage is controlled to that position, and then a line feed is performed. According to such a paper feed control method, the carriage can be controlled to an appropriate centering position according to the paper width, a large change in the centering position is prevented, and stable line feed, that is, paper feed control is realized. Therefore, printing defects such as skewed printing can be prevented.

Further, in the paper feed control device for a serial printer of the present invention, the centering position information of the carriage is stored in the storing means, the calculating means calculates the centering position of the carriage from the print data, and the changing means uses the calculation result as the calculation result. Based on this, the centering position information stored in the storage means is changed, and the centering operation of the carriage is performed by the control means in accordance with the centering position information stored in the storage means. Therefore, by using such a paper feed control device, the carriage can be controlled to the optimum centering position according to the width of the paper, a large change in the centering position is prevented, and stable line feed, that is, paper feed control is realized. Printing defects such as skewed printing are prevented.

Further, the paper feed control device of the serial printer of the present invention stores the centering position information of the carriage in the storing means, and the judging means determines whether or not the centering position information stored in the storing means should be changed from the print data. If it is determined that the centering position information should be changed by the determining means, the centering position information in the storage means is changed by the changing means, and the control means operates in accordance with the centering position information stored in the storage means. Carriage centering operation.
Therefore, if such a paper feed control device is used,
The carriage can be controlled to the optimum centering position according to the width of the paper, and a large change in the centering position can be prevented, and stable line feed, that is, paper feed control is performed to prevent printing defects such as skewed printing. .

[0014]

1 shows a paper feed control device used in a paper feed control method for a serial printer according to the present invention. This paper feed control device stores calculation means for receiving print information from a computer (not shown) and performing calculation as a basis for various control operations such as print processing and paper feed control, and storage means for storing print data given from the outside. A central processing unit (CPU) 22 is installed which serves as a determining unit that determines whether or not to change the centering position information, and a changing unit that changes the centering position information in the storage unit. The CPU 22 has a read-only memory (R) as means for storing fixed data and control programs.
OM) 24, write memory (RAM) 26 as a means for storing data in the middle of calculation and centering position information at any time
Are linked by a data bus 28 and an address bus 30. Further, an interface (I / F) 23 that receives print information from an external computer is connected to the CPU 22. The ROM 24 stores a print processing program, a paper feed control program such as line feed, and various processing programs, as well as fixed data such as a character font pattern. The RAM 24 stores various data in the process of arithmetic processing and the carriage 6 (see FIG. Data indicating the centering position of 6) is written at any time.

Further, the CPU 22 has a drive control circuit 34 as a control means for controlling the centering of the carriage 6.
Are linked via a data bus 28 and an address bus 30.

The drive control circuit 34 is an analog converting means for converting the logic level information from the CPU 22 into a drive voltage level for the drive system 36 for driving the carriage mechanism and the like, and the drive system 36 has a level corresponding to the logic level information. Drive voltage is supplied. The drive system 36 includes various actuators in the printer, such as a carriage drive system, a paper feed drive system, and a print head drive system.

The paper feed control method of the serial printer of the present invention having the above-mentioned structure will be described. When the power is turned on, the program starts, an initialization routine for initializing the entire printer is executed, and each part is checked and prepared. The initial setting value of the centering position information of the carriage 6 is stored in the ROM 24 together with other fixed data.
A predetermined value is stored therein, and the initial setting value is copied and stored in the RAM 26 during the initialization operation. And
When the initialization operation is completed, the printer waits for print data sent from the external computer. When print data is received from the external computer via the I / F 23, the print operation is started according to the print data.

Next, in FIG. 2, the centering position P is calculated when the centering operation of the carriage 6 is performed at the time of line feed.
The flowchart of the paper feed control method which performs control while setting is shown. When the processing for the centering operation of the carriage 6 is entered in the printing of the leading edge of the paper after absorbing the paper or the line feed during the printing, whether the next processing is the printing processing in step S1.
It is determined whether the line feed (LF) of the sheet.
If it is determined that printing is performed in step S1, step S
After one line is printed in step 2, the process proceeds to step S3. In step S3, the centering position is calculated and set based on the print data of one line.

If it is determined that the line feed is LF in step S1, the processes in steps S2 and S3 are not performed, and in this case, the centering position is not changed.

Then, in step S4, the centering operation of the carriage 6 is performed according to the centering position set by printing or the centering position carried over from the previous time by line feed. Next, in step S5, the paper is line-fed, the series of operations is completed, and the process proceeds to step S6.

In step S6, a range for performing centering, for example, a range from the leading edge of the paper to the 10th line is designated. If the centering operation of the carriage 6 is used within this range, the centering range is exceeded in step S6. It is determined whether or not it has not exceeded the centering range, and the process returns to step S1 and step S1.
After repeating a series of operations of 2, S3, S4, and S5, the process proceeds to step S6. Then, when it is determined in step S6 that the centering range is exceeded, or after the series of operations in steps S2, S3, S4, and S5 is repeated, and the printing is completed, the process proceeds to the next process.

Next, FIG. 3 shows a centering position calculation processing program of step S3 in the flow chart shown in FIG. In this program, step S
In step 31, half of the carriage movement amount (the number of steps of the carriage motor) β representing the actual print width on the paper 21 (FIG. 4) is obtained. This β / 2 represents the centering position of the print width. After the centering position β / 2 of the print width is obtained, the obtained centering position β / 2 is compared with the centering position α as the previous set value stored in the RAM 26 in step S32. That is, the centering position of the carriage 6 is set by
Compared with the conventional centering position α, the larger value is adopted as the centering position. This is for updating to a more appropriate centering position, and the conventional centering position α includes an initial setting value set when the power is turned on.

If α <(β / 2) in step S32, the process proceeds to step S33, the centering position α is updated to the centering position β / 2 in the register of the RAM 26, and then this process is terminated to proceed to the next step. Move to processing. That is, it can be estimated that the print width is large and the center of the paper width is on the right side of the centering position α as the previously set value.
Therefore, a new centering position β / 2 is set, the carriage 6 is controlled to this centering position β / 2, and then a line feed is performed.

If α <(β / 2) is not satisfied in step S32, the centering position α previously set is not updated and this process is terminated and the process proceeds to the next process.
In this case, the print width is narrow, and there is no reason to shift the centering position to the right. Therefore, line feed is performed and printing is continued without changing the centering position.

Next, FIG. 4 shows the calculation of the centering position and the centering operation. In FIG. 4, P ₁ indicates the reference position of the carriage 6, and P ₂ indicates the centering initial setting value. In this paper feed control, the print data L from the rightmost end points B and B ′ of the print data in one line on the paper 21 is printed.
Reference position P of the carriage drive motor at ₁ and L ₂
The paper width being printed is estimated from the number of movement steps β and β'from ₁ . For each paper width, the paper width is estimated based on the values of the printing step numbers β and β ′, and the centering position β / 2 or the centering position β ′ / 2 is calculated from the step numbers β and β ′ (step S31). The centering position is compared with the centering position α as the previously set value (step S32). Printing L ₁ is performed by this comparison, and when the value of the centering position β / 2 is smaller than the previous centering position α, or when the centering position β / 2 is on the left side of the centering position α, it is stored in the RAM 26. Without changing the value of the conventional centering position α, the process proceeds to the next process. Further, when the calculated centering position β ′ / 2 is larger than the centering position α which is the previously set value, the centering position β ′ / 2 is on the right side of the centering position α, so that the centering position α stored in the RAM 26 is After the value of the newly calculated centering position β ′ / 2 is updated, the carriage 6 is controlled to the centering position β ′ / 2, and the next processing such as line feed is started.

By such processing, the centering position α of the carriage 6 does not become smaller than the centering position α which is the initial setting value or the previous setting value, and the calculation and setting during the centering printing of the carriage 6 and the normal printing are performed. Also, since the carriage 6 is processed, the carriage 6 gradually approaches the center of the paper, which is the ideal centering position, according to the printing operation. In addition, the centering position α
Is reset by the paper-free state after the print is discharged and becomes the initial setting value, and then the above-mentioned operation is repeated. Also, once the power is turned off, the data stored in the RAM 26 will be lost, so when the power is turned on again, the R
It is returned to the initial setting value in the OM 24.

In the embodiment, the centering position α is stored in the storage means, and gradually shifts to the ideal centering position from the newly calculated magnitude relationship with the centering position, that is, the position information is updated. However, when the width of the paper is narrow and the movement of the centering position is so small that the bending of the paper is negligible, the centering position is changed for each line printing according to the print width, and the carriage 6 is moved to the centering position. You may control so that it may change at any time.

In this embodiment, the print data is analyzed line by line and line feed is performed after the centering update process. However, the print data can be received from the host computer over many lines at a time. In a printer having a line buffer or a page buffer, print data for a plurality of lines to be printed may be analyzed in advance to obtain the centering position.

[0029]

As described above, according to the present invention, the following effects can be obtained. a. The centering position is calculated according to the print data, the carriage is controlled at that centering position, and then a line feed is performed, so at the time of a line feed, the carriage can be placed at the ideal centering position according to the set paper width and line feed can be performed. Therefore, it is possible to reliably prevent printing defects such as skewed printing due to slack between the left and right edges of the paper. b. The previous centering position, such as the initially set centering position, is compared with the newly calculated centering position based on the print data, and the deviation between the two is compensated to obtain the ideal centering position for printing. It is possible to control the carriage, prevent line feed defects such as skewed printing due to differences in the slack of paper, and improve print quality. c. Even if the carriage centering position is initialized when the paper is changed or the power is turned on, the carriage is automatically controlled to the ideal centering position according to the start of printing, so pay attention to the carriage position when printing. It is not necessary and can contribute to simplification of the print start operation. d. In any case, in the present invention, the printer has a function of estimating the size of the paper used by analyzing the print data, and compared to the conventional method in which the centering position is fixed, line feed such as skew is generated. It is possible to reduce problems with time as much as possible and reliably improve the reliability of the low-cost printer.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a paper feed control device used in a paper feed control method for a serial printer according to the present invention.

FIG. 2 is a flowchart showing an embodiment of a paper feed control method for a serial printer according to the present invention.

FIG. 3 is a flowchart showing an embodiment of a paper feed control method for a serial printer according to the present invention.

FIG. 4 is a diagram showing a centering position showing an embodiment of a paper feed control method for a serial printer of the present invention.

FIG. 5 is a perspective view showing a carriage mechanism in the serial printer.

FIG. 6 is a diagram showing a centering position of a carriage in a conventional serial printer.

[Explanation of symbols]

 2 Platen 4 Guide Shaft (Guide Means) 6 Carriage 12 Print Head 21 Paper 22 CPU (Calculation Means, Judgment Means, Change Means) 26 RAM (Memory Means) 34 Drive Control Circuit (Control Means)

Claims (4)

[Claims] 1. A line feed having a carriage on which a print head is mounted, a platen on which a plurality of types of paper of different sizes are loaded, and guide means for guiding the carriage so as to be able to travel in parallel to the platen. In a paper feed control method for a serial printer that sometimes performs line feed while the carriage is centered, a centering position to be set in the carriage is calculated from print data for the paper, and the carriage is controlled at the centering position, and then the line feed is performed. A paper feed control method for a serial printer, characterized in that 2. A carriage having a print head, a platen on which a plurality of types of paper of different sizes are loaded, and guide means for guiding the carriage so that the carriage can run parallel to the platen. In a paper feed control method for a serial printer that sometimes performs line feed while the carriage is centered, the centering position to be set in the carriage is calculated from print data, and the centering position and the previous centering position stored in the storage means are calculated. If it is necessary to change it, the centering position of the storage means is updated, and the carriage is controlled to make a line feed at the centering position to make a change. If not, maintain the centering position of the storage means and Paper feed control method for a serial printer, characterized in that by controlling the carriage to the centering position of the line break. 3. A carriage having a print head, a platen in which a plurality of types of paper of different sizes are loaded, and guide means for guiding the carriage so that the carriage can run parallel to the platen. In a paper feed control device for a serial printer, which sometimes performs line feed while the carriage is centered, a storage unit that stores the centering position information of the carriage, a calculation unit that calculates the centering position of the carriage from print data, Change means for changing the centering position information stored in the storage means based on the calculation result, and control means for performing the centering operation of the carriage according to the centering position information stored in the storage means. Paper feed control device for serial printer. 4. A carriage including a print head, a platen in which a plurality of types of paper having different sizes are loaded, and guide means for guiding the carriage so that the carriage can run parallel to the platen. In a paper feed control device of a serial printer that sometimes performs line feed while the carriage is centered, a storage unit that stores the centering position information of the carriage, and the centering position information stored in the storage unit is changed from print data. Determining means for deciding whether or not to do so; changing means for changing the centering position information described in the storing means if the determining means determines that the centering position information should be changed; and the storing means The carriage centering according to the centering position information stored in A paper feed control device for a serial printer, comprising: a control unit that performs a printing operation.