JP5670938B2 - Dot matrix printer - Google Patents

Description

  Embodiments described herein relate generally to a dot matrix printer.

  In the conventional dot matrix printer, when italic characters are printed, printing is performed by shifting the dots constituting the characters in the horizontal direction.

  Therefore, the italic character is wider than the normal character.

  On the other hand, the printable range of the printer is limited. Specifically, the printer accelerates the head to the printing speed, prints at a constant speed, and then decelerates the head. Therefore, the printable range is a portion excluding the area used for acceleration and deceleration of the head from the movable range of the head. Since the movable range of the head is limited, the printable range is also limited.

  When italic characters are printed by the conventional method, it is impossible to print the italic characters on one line even though the characters to be printed can fit on one line.

  In this regard, a technique has been proposed in which when italic characters are printed, the moving speed of the head is slowed down, and the area used for acceleration and deceleration of the head is reduced to widen the printable range.

  However, this technique does not change the width of italic characters, so the width of one line printed with normal characters differs from the width of one line printed with italic characters. If normal characters and italic characters are printed on the screen, the appearance will deteriorate.

Japanese Patent No. 261989

  Therefore, there is a need for a dot matrix printer that can print the same number of characters as a normal character in one line and can print with good appearance.

In order to solve the above problems, an embodiment of the present invention provides a storage device that stores received print data, a print head that forms an image by abutting a pin against a recording medium, and a print that moves the print head. a head moving unit, and a recording medium transport mechanism for transporting the recording medium, the printing head HP sensor for detecting that the print head is in the home position, if the character to be printed of the print data is determined to be italic, character There is provided a dot matrix printer comprising a control unit that sets a print density high so that the width is narrower than italic .

2 is a block diagram illustrating a configuration of a dot matrix printer. FIG. FIG. 10 is a diagram illustrating a specific example of a method of reducing “the number of drive steps per second of the print head moving unit”. It is a figure which compares the printing in the case of an ordinary character, and the printing in the case of italic. It is a graph which compares the printing range in the case of a normal character, and the printing range in the case of italic. 3 is a flowchart illustrating an operation of a dot matrix printer.

  Hereinafter, an embodiment of a dot matrix printer will be described in detail with reference to the drawings.

  The dot matrix printer of the present embodiment includes a storage device that stores received print data, a print head that forms an image by abutting a pin on the recording medium, a print head moving unit that moves the print head, and a recording medium. A recording medium conveying mechanism for conveying, a print head HP sensor for detecting that the print head is at the home position, and a control unit for setting a high print density when it is determined that the character to be printed is italic among the print data; .

  FIG. 1 is a block diagram showing the configuration of a dot matrix printer according to this embodiment. As shown in FIG. 1, the dot matrix printer includes a CPU 101 that is a control unit, a storage device 102 that is a memory such as a ROM and a RAM, a print head 103 that forms an image by abutting pins on a recording medium, and printing. A print head moving unit 104 that moves the head 103, a recording medium conveyance mechanism 105 that conveys the recording medium, a print head HP sensor 106 that detects that the print head 103 is at the home position, and a detection that there is a recording medium. And a communication interface (hereinafter, the interface is referred to as I / F) 108.

  The storage device 102 includes a line buffer that stores print data received via the communication I / F 108.

  The print head 103 includes a pin that forms an image by coming into contact with a recording medium, and a pin drive mechanism that takes in and out the pin.

  The print head moving unit 104 includes a print head driving unit that moves the print head 103 along the recording medium width direction that is perpendicular to the recording medium conveyance direction. A stepping motor can be used for the print head drive unit.

  The recording medium transport mechanism 105 includes a guide for gripping the recording medium, a platen roller arranged to face the print head 103 across the recording medium transport path, and a platen roller driving unit that rotates the platen roller.

  The dot matrix printer controls the recording medium conveying mechanism 105 to convey the recording medium to the printing position, moves the print head 103 to the home position detected by the print head HP sensor 106, and stands by.

  When the dot matrix printer receives print data via the communication I / F 108, the dot matrix printer stores the received data in the storage device 102.

  The dot matrix printer determines whether the print data is italic. When the print data is italic, the dot matrix printer prints with a high print density, and when the print data is not italic, it prints at a normal print density.

  The print density is defined by the following equation (1).

(Print density [dpi]) =
((Printing head pin drive frequency [dot / s]) /
(Number of drive steps per second of the print head moving unit 104 [step / s])) /
(Moving amount [print / step] of print head 103 per one drive step of print head moving unit 104)
... (1)
The dot matrix printer (A) increases the “drive frequency of the print head pins”, (B) decreases the “number of drive steps per second of the print head moving unit 104”, and (C) “moves the print head. The print density is increased by selecting at least one of the three methods of reducing the “movement amount of the print head 103 per driving step of the unit 104”.

  (A) The method of increasing the “print head pin drive frequency” depends on the type of print head.

  When the print head 103 can change the pin drive frequency by PWM control, the dot matrix printer increases the pin drive frequency by PWM control of the power supplied to the print head 103.

  When the print head 103 can change the drive frequency of the pin by the drive signal from the control unit, the dot matrix printer transmits a control signal for increasing the drive frequency of the pin to the print head 103.

  (B) The method of reducing “the number of driving steps per second of the print head moving unit 104” is performed by the control unit controlling the operation of the print head moving unit 104.

  Specifically, the dot matrix printer increases the time from when the control unit drives the print head drive unit of the print head moving unit 104 to the next drive, so that the print head moving unit 104 per second That is, the number of drive steps per unit time is reduced.

  FIG. 2 is a diagram illustrating a specific example of a method for reducing the “number of drive steps per second of the print head moving unit 104”. 2A is a timing chart when the printing density is relatively high, and FIG. 2B is a timing chart when the printing density is relatively low.

  As shown in FIGS. 2A and 2B, when italic characters are printed, assuming that the fire timing of the print head pin, that is, the protrusion timing is the same, each phase of the print head drive unit is turned ON / OFF. The printing density can be increased by extending the timing from the ON / OFF timing when printing ordinary characters.

  More specifically, in FIG. 2A, a chart 201 shows print head pin timing. Each time the chart moves up and down once, the print head pin protrudes once and is pulled back.

  Charts 202 to 205 show ON / OFF timings of the print head driving unit A phase to D phase. The top and bottom of the chart indicate ON / OFF. Here, it is assumed that the print head driving unit is a four-phase stepping motor.

  An arrow 206 indicates a time interval of one step.

  In FIG. 2B, a chart 211 shows print head pin timing. Each time the chart moves up and down once, the print head pin protrudes once and is pulled back.

  Charts 212 to 215 show ON / OFF timings of the print head driving unit A phase to D phase. The top and bottom of the chart indicate ON / OFF.

  An arrow 216 indicates a time interval of one step.

  In the example shown in FIG. 2A, the ON / OFF cycle of the print head driver A phase to D phase is longer than the ON / OFF cycle of the example shown in FIG. Therefore, the time interval of one step is relatively longer in the example shown in FIG.

  Accordingly, if the ON / OFF timing of each phase of the stepping motor of the print head driving unit is extended from the ON / OFF timing for printing normal characters, the “number of driving steps per second of the print head moving unit 104” is small. Thus, the print density is increased.

  (C) The method of reducing “the amount of movement of the print head 103 per drive step of the print head moving unit 104” is performed by using a transmission gear.

  The transmission gear includes a HIGH gear that moves the print head 103 at a high speed, a LOW gear that moves the print head 103 at a low speed, and an electromagnetic clutch that switches between the HIGH gear and the LOW gear.

  The dot matrix printer drives the electromagnetic clutch and moves the print head 103 at a low speed by switching from the HIGH gear to the LOW gear.

  If the drive time per drive step of the print head moving unit 104 is constant, the amount of movement of the print head 103 per drive step of the print head moving unit 104 can be reduced by using the LOW gear. It becomes.

  FIG. 3 is a diagram for comparing printing in the case of normal characters and printing in the case of italics. As shown in FIG. 3, the print width of ordinary characters shown in FIG. 3A, and the italic print width when printing is performed at a high print density according to the present embodiment shown in FIG. Can be the same.

  That is, the dot matrix printer prints italics at 59 dpi when printing ordinary characters at 36 dpi.

  The dot matrix printer can print italics at a print density other than 59 dpi. The higher the print density, the more characters can be printed in a line.

  FIG. 4 is a graph comparing the print range for normal characters and the print range for italics. FIG. 4A shows an ordinary character, and FIG. 4B shows an italic case.

  As shown in FIG. 4A, the normal character print range is printed at a speed V1, so that the print head 103 acceleration range (HP to P1) is changed from the movable range (HP to P3) of the print head 103. And the range is narrower than the deceleration range (P2 to P3) of the print head 103.

  As shown in FIG. 4B, the italic print range is for reducing the “number of drive steps per second of the print head moving unit 104” and moving the print head 103 at a speed V2 slower than the speed V1. The italic print range can be expanded to P4 to P5.

  FIG. 5 is a flowchart showing the operation of the dot matrix printer. As shown in FIG. 5, in operation 401, the dot matrix printer determines whether print data has been received. If it is determined that the print data has been received, the dot matrix printer proceeds to operation 402; otherwise, the operation returns to operation 401.

  In operation 402, the dot matrix printer stores the received print data in the storage device 102.

  In operation 403, the dot matrix printer determines whether the print data is italic. The dot matrix printer proceeds to operation 404 when the print data is italic, and proceeds to operation 405 when the print data is not italic.

  In act 404, the dot matrix printer is set to increase the print density.

  In operation 405, the dot matrix printer prints with the set print density, and returns to operation 401.

  As described above, the dot matrix printer according to the present embodiment moves the storage device 102 that is a memory such as a ROM and a RAM, the print head 103 that forms an image by abutting pins on a recording medium, and the print head 103. The print head moving unit 104 to be moved, the recording medium transport mechanism 105 for transporting the recording medium, the print head HP sensor 106 for detecting that the print head 103 is at the home position, and the recording medium detection for detecting the presence of the recording medium. The sensor 107, the communication interface 108, and a control unit that sets the print density high when it is determined that the character to be printed is italic.

  Therefore, it is possible to print the same number of characters as a normal character in one line, and it is possible to print with good appearance.

  Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

101: CPU
102: Storage device 103: Print head 104: Print head moving unit 105: Recording medium transport mechanism 106: Print head HP sensor 107: Recording medium detection sensor 108: Communication I / F

Claims (4)

A storage device for storing the received print data;
A print head for forming an image by abutting pins on a recording medium;
A print head moving section for moving the print head;
A recording medium transport mechanism for transporting the recording medium;
A print head HP sensor for detecting that the print head is at a home position;
When it is determined that the character to be printed out of the print data is italic, a control unit that sets the print density high so that the character width is narrower than the italic ;
A dot matrix printer. The controller is
The dot matrix printer according to claim 1, wherein the print density is increased by reducing the number of driving steps per unit time of the print head moving unit. The controller is
2. The dot matrix printer according to claim 1, wherein the print density is increased by increasing the drive frequency of the pins of the print head. The controller is
The dot matrix printer according to claim 1, wherein the print density is increased by reducing the amount of movement of the print head per driving step of the print head moving unit.

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