JPH0425873B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of controlling a serial printer having a print head that moves back and forth along a platen and means for detecting the position of the print head.

[Conventional technology]

Conventional serial printers that use a print head that moves back and forth along the platen to print desired characters on paper set on the platen include narrow-width type printers for personal use, mainly used for personal computers, etc., and printers for forms, etc. Wide type printers for business use are commonly used for printing.

Of these two types of printers, the former narrow-width type printer has 10 characters/inch (picapitschi).
The printer prints 80 characters per line, and the latter wide type printer prints 130 characters per line.

Since the two types of conventional printers have different numbers of digits printed per line, there are two types of control programs for the microprocessor built into the printer, and these two types of control programs are stored. As memory for this purpose, a ROM for narrow-width printers and a ROM for wide-width printers were required.

[Problem that the invention seeks to solve]

However, when preparing two types of ROM to store control programs for two types of printers, it is necessary to manage the design and manufacturing of each separately, and when the ROM is used as a mask ROM, There was a problem in that the manufacturing costs for two types of masks were high, making them expensive.

The present invention was made to solve this problem, and uses a position detection means to detect the position of the print head to enable two types of printers, a narrow type and a wide type, to be operated at the same time using one type of ROM. The purpose of this invention is to realize a control program that can be controlled by a control program of 100%, thereby reducing the management of ROM design and manufacturing, and at the same time reducing the cost of using a ROM as a mask ROM.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention moves the print head from one end of its movable range to the other end when the power of the printer is turned on, and detects sensor pulses generated from the sensor of the position detection means as the print head moves at this time. The distance traveled by the print head is measured by counting with a counter.

The number of printed digits per line is determined based on the measurement results, and the determined result is stored in a storage element, so that two types of printers with different numbers of printed digits are controlled by the same control program.

[Effect]

According to the above-described means, it is determined whether the printer is a narrow-width type or a wide-width type before printing, and the printing process is performed according to the control program accordingly.

Therefore, according to this, it is possible to use the same ROM even in printers with different numbers of printing digits.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a flowchart of a control program for determining the number of printed digits to explain an embodiment of a method for controlling a serial printer according to the present invention, and FIG. 2 is a schematic plan view of a serial printer to which the present invention is applied. It is.

First, to explain the serial printer shown in FIG. 2, 1 is a platen, and both ends of the central axis of the platen 1 are rotatably supported by left and right side plates 2a, 2b, and this central axis is not shown. It is connected to a step motor for line feed, and when the platen 1 is rotated by this motor, printing paper (not shown) that is wound around the platen 1 and set is fed.

A shaft 3 has both ends fixed to the side plates 2a and 2b, and the shaft 3 is arranged parallel to the platen 1. This shaft 3 is provided with a movable carriage,
A print head 4 is mounted on the carriage.

Further, a space motor (not shown) is connected to the carriage via a wire, belt, or gear (also not shown), and the rotation of this space motor causes the printing head 4 to move along the platen 1 and the shaft 3 together with the carriage. While moving above, printing is performed on the printing paper set on the platen 1.

Although not shown, as a position detection means for detecting the position of the print head 4, a disk having a slit is connected to the rotating shaft of a space motor in a gear-down manner, and the disk rotates as the print head 4 moves. The position of the print head 4 is detected by detecting the slit with a photo sensor or magnetic sensor, or the position of the print head 4 is detected by mounting the disk on a carriage and similarly detecting the slit with a sensor. things etc. are used.

Next, a method of controlling the serial printer having the above-described configuration will be explained based on FIG.

First, when the power is turned on to the printer, the initial setting program resets the driver circuit and interface circuit and sets the initial state, and then the origin positioning operation of the carriage equipped with the print head 4 (usually the first When moving the print head 4 to the printing start position of the character, the control program for determining the number of printing digits shown in FIG. 1 is executed.

In step 1 of FIG. 1, the print head 4 is moved to the right in FIG. 2 by the rotation of the space motor, and at the same time, the aforementioned disk rotates and its slit is detected by the sensor, thereby generating a sensor pulse. While the sensor pulse is being generated, the print head 4 is moving to the right, and when the print head 4 reaches one end of its movable range, that is, when it hits the side plate 2a on the right side of the print head 4 and stops. , the space motor will no longer be able to rotate. The rotation of the disc is therefore also stopped and no sensor pulses are generated.

Here, the control program for determining the number of printed digits advances to step 2.

In step 2, the space motor rotates in the opposite direction to move the print head 4 to the left, and the slit in the disc is detected by the sensor in the same manner as described above, generating a sensor pulse. The sensor pulses at this time are successively counted by a counter, and when the print head 4 reaches the other end of the movable range, that is, when it hits the left side plate 2b and stops, no sensor pulses are generated. The control program for determining the number of printed digits advances to the next step 3.

In step 3, the distance traveled by the print head 4 from one end of its movable range to the other end is calculated from the number of sensor pulses counted in step 2,
Based on the result, the number of printing digits for one line of the printer is determined.

For example, in this embodiment, it is assumed that one sensor pulse is generated by the slit in the disk when the print head 4 moves by 1/480 inch, and that the distance between the left and right side plates 2a and 2b, that is, the movement of the print head 4 If the possible range is 8.5 inches for a printer that prints 80 digits per line and 14.5 inches for a printer that prints 136 digits, the former printer will count 8.5 x 480 = 4080 sensor pulses, and the latter printer will count 14.5 x 480=6960 sensor pulses will be counted.

When determining the number of printing digits, take into account variations in the mechanism, etc.
The printer is designed to print 80 digits with less than 4200 pulses, and the printer can print 136 digits with more than 4,200 pulses.

The result of this determination is set in the bit FLAG for determining the number of printed digits allocated to the RAM as a storage element by the control program. for example
If it is determined that it is 80 digits, the FLAG is logic “0”
If it is 136 digits, FLAG is set to logic "1".

Thereafter, the print head 4 is moved to the printing start position of the first character, and the control program for determining the number of printing digits is ended.

Thereafter, in the printer control program, the state of the FLAG is checked by the printing digit management program, and processing is performed depending on the number of printing digits, 80 digits and 136 digits.

In addition, in this example, the number of printing digits per line is 80.
Although the discrimination between digits and 136 digits has been described, the present invention is not limited to this, and it is also possible to discriminate other differences in the number of printed digits.

Furthermore, if the moving speed of the print head 4 and the carriage when determining the number of printing digits mentioned above is controlled to be lower than the normal printing speed, it is possible to reduce the speed when the print head 4 hits the left and right side plates 2a and 2b. The shock can be almost completely eliminated.

〔Effect of the invention〕

As explained above, the present invention moves the print head from one end of its movable range to the other end when the power of the printer is turned on, and measures the moving distance of the print head using the position detection means, thereby printing one line. This system determines the number of digits and stores the determined result in a memory element, making it possible to control two types of printers with different numbers of printing digits with the same control program. The number of ROMs that store control programs that were previously manufactured for printers can now be reduced to one type.

Therefore, the management of ROM design, manufacturing, sales, maintenance, etc. can be reduced by half compared to conventional methods, and even when a mask ROM is used as the ROM, the mask manufacturing cost can be reduced by half. It will be done.

Furthermore, the present invention moves the print head when the power is turned on and determines the number of printing digits by measuring the distance it has moved using position detection means that serial printers generally have. It can be carried out automatically without adding any means, and there is also an advantage that the printer price does not increase.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a control program for determining the number of printed digits to explain an embodiment of the printer control method according to the present invention, and FIG. 2 is a schematic diagram showing an example of a serial printer to which the present invention is applied. FIG. 1...Platen, 2a, 2b...Side plate, 3...Shaft, 4...Print head.

Claims (1)

[Claims] 1. A print head that reciprocates along the platen;
and a control method for a serial printer having a position detection means for detecting the position of the print head, the method comprising: moving the print head from one end of its movable range to the other end when the power is turned on; and determining the distance the print head moves at this time. is measured by the position detecting means, the number of printing digits for one line is determined based on the measurement result, and the result of the determined number of printing digits is stored in a storage element, so that printers with different numbers of printing digits can be used in the same printer. A method for controlling a serial printer, characterized in that it is controlled by a control program.