JPS6328663A - Impact-type dot printer with noise reduction function - Google Patents

Abstract

PURPOSE:To reduce a printing noise by changing a printing speed or performing a printing through the subdivision of a printing line into a plurality of portions in a given time when a printing signal for the reduction of a noise is entered from a command issuing part. CONSTITUTION:A printing density is arithmetically operated by a printing density arithmetic operation part based on a total printable dot count in a prearranged printing area and the dot count of a printing pattern to be actually printed. A printing control part changes a printing speed and prints characters in a printing line unit or an in-line area unit, or prints characters in a plurality of subdivided portions, for instance, based on the above-mentioned arithmetically operated printing density, if a printing mode for the reduction of a noise is commanded by a printing command part. Consequently, if the operation is set to 'low noise mode', the drive frequency per unit time of an impact wire is controlled in accordance with the size of a printing density, so that a printing nose can be restrained without the deterioration of a printing speed beyond the limit of necessity.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to reducing print noise in impact dot printers.

[Prior art]

Conventionally, in impact type dot printers that drive impact wires according to the dot pattern to form character patterns on paper, the driving sound of the impact wires during printing operations becomes louder, which has become a problem as a source of noise. There is. In order to reduce such noise, a case is placed over the printer body, but the case must be removed one by one when taking out printed matter after printing, which is a complicated operation. Furthermore, in order to essentially reduce printing noise, there is a method of reducing the driving frequency of the impact wire per unit time. However, reducing the driving frequency of the impact wire also reduces the printing speed, resulting in a decline in the functionality of the printer. Therefore,
A normal printing mode and a low noise printing mode can be freely set using a changeover switch, and the printing operation is controlled to be performed in the low noise printing mode according to the user's selection.

[Problems to be solved by the invention]

However, the driving frequency of the impact wire is not constant over time, and it depends on the dot density of the printed pattern. That is, the noise generated when printing a pattern with a low dot density is reduced. For this reason, in the conventional method of setting the low noise mode using a changeover switch, regardless of the dot density of the printed pattern, the driving frequency of the impact wire is significantly reduced, resulting in a low dot density. Even when there is no need to reduce printing noise, there is a problem in that the printing speed is unnecessarily reduced.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the printing noise of impact type dot printers.

[Means to solve the problem]

The structure of the invention to solve the above problem is to move the print head along the print line and strike the wire on the paper in accordance with the dot pattern! In an impact type dot printer that forms a printed dot pattern by using a print head, the present invention includes a command unit that arbitrarily switches between printing for reducing noise and normal printing, and printing in a predetermined printing area printed by the print head. a printing density calculation unit that calculates printing density based on the total number of dots that can be printed and the number of dots in the printing pattern that is actually printed; The present invention includes a print control section that changes the printing speed according to the print density calculated by the density calculation section, or divides and prints a print line a plurality of times according to the print density.

[Effect]

The print density calculation section calculates the print density in a predetermined print area based on the total number of dots that can be printed in the predetermined print area and the number of dots in the actually printed print pattern. Print density can be calculated, for example, by using the average value within a unit print line as the print density for that line, by using the average value in a divided area that does not overlap within a line as the print density for that area, or by using the average value within a line as the print density for that area. However, a method can be adopted in which an area that can be moved approximately continuously is set and the average value of the area is set as the print density of the moving area. Print! 'Il control unit, when a print mode that reduces noise is commanded from the print command unit, changes the printing speed in units of print lines or areas within lines, for example, according to the print density calculated as above. Print multiple times or print in multiple batches. Therefore, when the low noise mode is set, the driving frequency of the impact wire per unit time is controlled according to the printing density, so printing noise can be suppressed without reducing the printing speed more than necessary. I can do it.

【Example】

The present invention will be described below based on specific examples. In FIG. 1, reference numeral 1 denotes a central processing unit (CPU) constituting a control device of the printer. CPtJl is input buffer A
It is connected to a host computer 14 via an input/output interface 13 having
4, non-character symbol system codes such as character symbol system codes and function codes are input. CPU 1
R via the address bus, data bus, and control bus.
OM2, RAM3, and input/output interface 4°5.6 are connected respectively. The ROM 2 is provided with a phono ROM 21 in which a font pattern of 22.24 x 24 dots is written. Further, in the RAM 3, a line buffer for creating a print pattern for one line, a work area used by the CPU 1, etc. are formed. The input/output interfaces 4, 5, and 6 each have a drive bag! ? . , are connected to each other. These are driven by the CPU 1 based on the dot patterns formed in the line buffer and functional processing based on commands input from the host computer. The above-mentioned command unit, print density calculation unit, and print control unit mainly include the CPU 1, ROM 2,
It is implemented by a computer system composed of a RAM 3, an interface 13, etc., and its functions are realized by a print control program stored in a ROM 2. FIG. 2 is a flowchart showing the processing procedure of the CPU 1, and the operation of the present device will be explained with reference to it. When the device is powered on, any necessary initialization of the device is performed (100). This initialization brings the printer online and connects it to the host computer. Next, CPU 1 accesses input buffer A and waits until the buffer becomes full (102). When the buffer is full, it means that data has been received from the host computer, so the input data is read (103) and the type of data is determined (104).
). In the case of a character symbology code (a code corresponding to a print pattern including spaces), the font ROM 21 is accessed from the code and an output image corresponding to the line buffer is formed (106). This process is repeatedly executed on the character symbology code, and output dot images are sequentially formed in the line buffer. When a code other than the character symbol system code is input, the process moves to step 108, and when it is determined to be a print command code such as LF:FF:CR, steps 110 and subsequent steps are executed, and when other codes are input, The process branches to step 130. When it is determined in step 130 that the input command instructs the low noise printing mode, the mode flag FLG is set to 1 in step 132, and then the process returns to step 102 for inputting data. Also, step 134
If it is determined that the input command instructs the normal printing mode without low noise control, the mode flag FLG is set to 0 in step 136, and the process returns to step 102. Further, if the input command is other than the above, the functional process corresponding to the command is executed (138). For example, when a function command instructs input of image data, the following data is input and formed directly in the line buffer as image data. Further, when a command for vertical enlargement or horizontal enlargement is given, parameters necessary for converting data from the ROM 21 are set. Next, when it is determined that it is a print command code, step 110
Then, the mode flag FLG is determined, and if it is the normal printing mode, the process moves to step 140, and as is normally done,
Print one line at a time. In the low noise printing mode, the printing density of the output image stored in the line buffer is calculated. As shown in Fig. 3, the printing density N is the total number of dots W, which is the number of columns up to the printing end (first column) multiplied by the number of dots in one column ω, and The number of dots (1, etc.) that are turned on up to the printing end ('f! JJ column) is defined as the number A of dots actually printed, and is determined by A/W. Next, the size of the print density N determined is determined in steps 114 to 118. Here, the determination Me value is N+>N2>Ns. When N2H4, the print line is divided into n1 times and printed (122), and when N,>N≧N2, the print line is divided into n1 times and printed.
When N2)N2H, the print line is divided into n5 times and printed (126).
, when Ns>H, it is printed at once without dividing (12
0). Here, n l>n 2>n 3. For example, in the case of two-part printing, split printing is performed by printing separately into odd-numbered dot rows and even-numbered dot rows, or by printing separately into upper half dots and lower half dots. You can take the following method. As described above, the printing density of a printing line is calculated and printing is divided into a number of times according to the printing density, so the number of impact wires driven at the same time is reduced and averaged, and printing noise is also reduced. This is an averaged low value regardless of print density. In the above embodiment, the printing line is divided into multiple parts according to the printing density, and the printing speed is reduced as the printing density increases. You can also do it. Furthermore, in the above embodiment, the predetermined printing area for calculating the printing density is set for each printing line, but as shown in FIG. While moving toward the end of printing (first column), the printing density within the area at each time may be calculated, and the maximum value may be controlled as the printing density of that printing line. If the area is wide, the printing density will be averaged if there are areas with high printing density and areas with low printing density in one printing line, and the noise reduction effect of the area with high printing density cannot be expected. However, if the printing of the line is controlled using the maximum printing density of the moving area, the noise will be reduced even if there is a partially high printing density area. In addition, in the above embodiment, division printing is controlled for each printing line, but division printing or speed printing may be performed for each divided area within one printing line according to the printing density of that area. .

【Effect of the invention】

As described above, the present invention calculates the printing density in a predetermined printing area, and when in the low noise mode, prints by dividing the printing line into multiple times or changing the printing speed depending on the calculated printing density. It is characterized by printing at a lower level. Therefore, since the printing speed does not uniformly decrease more than necessary, it is possible to achieve both noise reduction and high-speed printing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a printer according to a specific embodiment of the present invention, FIG. 2 is a flow chart showing the processing procedure of the CPU used in the printer, and FIG. FIG. 3 is an explanatory diagram showing a method of calculating print density. Patent applicant Agent: Brother Industries, Ltd.
Patent Attorney Osamu Fujitani00・・・・・・・・・・0

Claims (1)

[Claims] (1) Printing to reduce noise in an impact-type dot printer that moves the print head along the print line and strikes the paper with a wire in accordance with the dot pattern to form a print dot pattern. a command unit that arbitrarily switches between normal printing and normal printing; and a command unit that calculates printing density based on the total number of dots that can be printed in a predetermined printing area printed by the print head and the number of dots of the printing pattern that is actually printed. When a printing signal for reducing noise is input from the printing density calculation section and the command section, the printing speed is changed according to the printing density calculated by the printing density calculation section, or the printing speed is changed according to the printing density. An impact type dot printer having a noise reduction function, characterized in that it is provided with a print control unit that prints a print line by dividing it into a plurality of times.