JP2658715B2 - Thermal 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 thermal printer for printing a character such as a character on a print medium by using a thermal print head while relatively moving the thermal print head and a print medium via a pulse motor. The present invention relates to a method of controlling the printing energy of energized dots when a certain number or more of energized dots continue several times or more depending on a print pattern such as a character.

[0002]

2. Description of the Related Art Conventionally, a moving mechanism is controlled by a pulse motor to relatively move a thermal printing head and a printing medium such as printing paper, thereby printing characters such as characters on the printing medium via the thermal printing head. Thermal printers adapted to do so are well known.

By the way, in such a thermal printer, depending on the printing pattern of the character or the like, the number of simultaneously energized dots is large several times, or the number of simultaneously energized dots is small several times. There is.

For example, as shown in FIG. 6, when the character "1" or the character "H" is taken as an example, the printing direction indicated by the arrow in the figure indicates that the thermal print head moves the printing medium surface relative to the printing medium surface. The vertical direction refers to the direction in which the heating elements of the thermal print head are arranged. In the case of a character with an underline "1" of one vertical dot, the number of energized dots is increased from the beginning. Less to the end.

Further, in the case of the character "double-width bold" H ", the state where the number of energized dots is large several times continues.

In such a case, conventionally, a constant amount of energy has been applied without changing the amount of energizing energy to each heating element.

[0007]

However, according to the thermal printer of such a control, the underline "1" of one vertical dot and the "H" of the double-width bold due to the influence of heat from the surrounding dots, even during the same energizing time. A large and small number of energized dots in the vertical direction, such as "."

[0008] In this case, unevenness of shading and blurring between characters in a state where a large number of characters are printed on the printing medium surface is conspicuous,
There was a problem that the appearance was impaired. In addition, problems such as shading and blurring occur in one character.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to secure the printing of characters and the like of good printing quality without unevenness of shading of printing dots or blurring. It is something you want to do.

Another object of the present invention is to achieve an improvement in energy efficiency, a reduction in the size of a power supply, and the like by controlling the amount of energizing energy of printing dots.

[0011]

In order to achieve the above object, a thermal printer according to the present invention is arranged such that a thermal print head and a print medium are relatively moved while moving in a direction intersecting the relative movement direction of the thermal print head. In a thermal printer that sequentially and selectively applies energizing energy based on print information to a large number of heating elements and prints desired characters and the like on the printing medium surface, the number of heating elements to which the energizing energy is applied simultaneously Is m (m is an integer of 1 or more)
A first determination unit for determining whether or not the number is equal to or more than a number, and a second determination unit for determining whether or not the number of prints determined to be m or more by the first determination unit is continuous (n is an integer of 2 or more). A determination unit; and an energization control unit configured to reduce the amount of energization energy to each heating element in subsequent printing when it is determined by the second determination unit that the number is n or more.

[0012]

According to the thermal printer of the present invention constructed as described above, when the first judging means judges that the number of the heating elements to which the energizing energy is applied simultaneously is m or more, the second judgment is made. When the determining means determines that the number of the prints determined to be m or more is continuous for the number n or more, the energizing control means reduces the amount of energizing energy to each heating element in subsequent printing.

Therefore, even if the number of heating elements to which the energizing energy is applied continues for several dots, the overheating state of the heating elements is avoided, and printing at an almost constant temperature state is continued.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a tape printer according to an embodiment of the present invention;
FIG. 1 is a plan view of the tape printing apparatus in which a storage cover of a tape cassette storage unit is opened.

Referring to FIG. 1, a tape printer 1 includes a character input key 2 for inputting characters and the like, a print key 3, a direct print selection key D, and a keyboard 4 provided with various other function keys. A liquid crystal display 5 for displaying input characters and the like, and a cassette housing section 6 for housing a tape cassette 20, which will be described later, are provided.

The cassette housing section 6 is driven to rotate by a pulse motor 45 described later,
The ribbon winding shaft 7 for rotating the ribbon winding spool 28 for winding the thermal ink ribbon 24 by rotating the ribbon winding spool 28 is provided.
A tape feed roller shaft 8 for rotating a tape feed roller 33, which will be described later, is rotatably driven by a pulse motor 45 through an appropriate transmission mechanism, and is provided obliquely forward (on the keyboard 4 side). I have.

Further, a thermal head 9 for performing printing on a film tape 22 to be described later via a thermal ink ribbon 24 is fixedly provided in front of the cassette housing section 6. The thermal head 9 is perpendicular to the feeding direction of the film tape 22 and the thermal ink ribbon 24.
The heating elements are arranged in tandem.

The cassette storage section 6 includes a storage cover 10 rotatably supported behind the tape printer 1.
The tape cassette 20 is exchanged in the open state.

Next, the configuration of the tape cassette 20 will be described with reference to FIG. FIG. 2 is a plan view showing a state where the tape cassette 20 is stored in the cassette storage section 6 (the tape cassette 20 is shown excluding the upper case).

Referring to FIG. 1, a lower case 21 has a tape spool 2 on which a transparent film tape 22 is wound.
3, a ribbon spool 25 around which the thermal ink ribbon 24 is wound, and an adhesive tape spool 27 around which a double-sided adhesive tape 26 with release paper is wound with the release paper side facing out. Reference numerals 25 and 27 are rotatably supported in cooperation with a support portion provided on the lower surface of the upper case (not shown).

A ribbon take-up spool 28 is similarly rotatably supported between the spools 23, 25, and 27. The ribbon take-up spool 28 is engaged with the ribbon take-up shaft 7 to form a ribbon take-up. By driving the take-up shaft 7, the thermal ink ribbon 24 used for printing is taken up.

Further, the thermal head 9 is disposed in a concave portion 29 provided in the lower case 21, and a platen roller 30 rotatably supported by a roller holder H is disposed on the thermal head 9 so as to oppose in a pressed state. ing. The thermal head 9 prints characters such as characters on the film tape 22 via the thermal ink ribbon 24.

Further, the tape discharging portion 31 of the lower case 21
(The lower left side in FIGS. 1 and 2) and the tape pressing roller 32
Is rotatably supported, and a tape feed roller 33 rotatably supported by a roller holder H is opposed to the tape pressing roller 32 in a pressed state.

In the cassette storage section 6, a roller holder H is pivotally supported by a support shaft 34 in front of the tape cassette 20 (lower side in FIGS. 1 and 2), and the roller holder H is not shown. The print position and the release position can be switched by a manual switching mechanism (FIG. 2 shows a state where the print position is switched to the print position).

As shown in FIG. 2, the platen roller 30 and the tape feed roller 33 are provided on the roller holder H so as to be rotatable and pressed against the thermal head 9 and the pressure roller 32, respectively. ing.

Further, the tape discharge section 31 which is located downstream of the thermal head 9 in the feeding direction of the film tape 22.
Is provided with a cutter mechanism K in the vicinity of. The cutter mechanism K has the same configuration as a known scissors, and includes a fixed blade and a movable blade (not shown). The movable blade is driven by a DC motor 35 via an appropriate gear mechanism.

The pressure contact roller 32 and the tape feed roller 33 cooperate with the double-sided adhesive tape 2 on the film tape 22 on which characters such as characters are printed by the thermal head 9 via the thermal ink ribbon 24.
The pressure-sensitive adhesive surface of No. 6 is pressure-bonded to finally form a tape M.

Next, a control system of the tape printer will be described with reference to FIG. FIG. 3 is a block diagram of the tape printing apparatus, which is configured with a control device (hereinafter, referred to as a CPU) 40 as a core. In FIG. 3, a keyboard 4 is connected to a CPU 40, and the CPU 40 operates a character input signal input from a character input key 2 of the keyboard 4 and various functions input from function keys such as a print key 3 and a direct print selection key D. Determine the input signal.

An R0M 41 is connected to the CPU 40. The ROM 41 has a built-in printing character generator for generating characters such as characters printed by the thermal head 9.

Further, the ROM 41 includes a display character generator for generating characters and the like displayed on the liquid crystal display 5, a pulse motor control program for controlling the drive of the pulse motor 45, and other necessary information for controlling the tape printer. Various programs are stored. Particularly, a control program of the energization energy shown in FIG. 4 described later is stored.

The RAM 42 connected to the CPU 40
Is a memory for temporarily storing various data. A print buffer, a display buffer, and other external characters in which data such as characters read from the two character generators are expanded into print data or display data and stored. A memory such as an external character pattern buffer for registering pattern data is provided.

The RAM 42 is provided with a memory area for a continuous dot counter and a reset counter as shown in the flowchart of FIG. Further, the liquid crystal display 5 is connected to the CPU 40 via a liquid crystal display driving circuit 43, and the CPU 40 drives the liquid crystal display driving circuit 43 based on the display data stored in the display buffer of the RAM 42 and is input to the liquid crystal display 5. Display the displayed characters.

The CPU 40 controls the pulse motor 45 by driving the pulse motor drive circuit 44 based on the program stored in the ROM 41, thereby controlling the feed of the tape T in synchronization with the printing by the thermal head 9. Do.

Similarly, the CPU 40 controls the DC motor 35 by driving the DC motor drive circuit 46 based on the program stored in the ROM 41.

Further, the thermal head 9 is connected to the CPU 40 via a thermal head drive circuit 47.
The CPU 40 drives the thermal head drive circuit 47 based on the print data stored in the print buffer of the RAM 42, and prints characters and the like on the film tape 22 by the thermal head 9.

According to the present invention, in such a 128-dot thermal printer, when a character pattern in which the number of energized dots of the thermal print head 9 exceeds 96 dots continues for four or more dots, the energizing time is set from the fourth dot. Shorten to limit energizing energy.

Next, the character pattern below 96 dots is 2
When the dot continues, the energization time is returned to normal from the third dot, and the restriction on the energization energy is released.

FIG. 4 is a flowchart showing the operation. First, a printing pattern of a vertical line is determined (Step 2) from a state where each counter is initialized (Step 1).

From this state, it is determined whether or not the number of simultaneously energized dots (m) of the current vertical line is equal to or greater than a set value (m0) (step 3). If the determination is YES, the continuous dot counter is incremented (step 4).

Next, it is determined whether or not the incremented value of the continuous dot counter is 4 or more (step 5). If NO, printing is performed with normal energizing energy (step 6). For example, the reset counter is returned to zero (step 7), and printing is performed using "energy-limited data" (step 8).

On the other hand, if it is determined in step 3 that the number of simultaneously energized dots (m) is not greater than the set value (m0), the reset counter is incremented (step 9).

It is determined whether the incremented value of the reset counter is 3 or more (step 1).
0), if NO, the printing of "with the above-described energy-limited data" is continued (step 11), and if YES, the value of the continuous dot counter is returned to zero (step 1).
Along with 2), printing is performed with normal energizing energy (step 6).

FIG. 5 is an enlarged view of a specific dot printing state. Below that, the length of energization time for each dot line is shown. In this figure, the number of simultaneously energized dots (m) exceeds the set value (m0) from the beginning to the fourth dot, and the following three dots indicate that the number of simultaneously energized dots (m) is less than the set value (m0). Show.

In this case, according to the above-described flowchart, printing is performed with normal energizing energy up to the first third dot, and printing is performed with limited energy in the next fourth dot. That is, the normal heat generation time is given to the first third dot, and the “short heat generation time” is given to the next fourth dot.

In the next three dots, the number of simultaneously energized dots (m) is equal to or smaller than the set value (m0), and the first two of the three dots have the limited energized energy according to the above-described flowchart. Printing is continued, and printing is performed again with normal energizing energy at the next third dot.

Also in this case, the limitation of the energizing energy is achieved by a short heating time, and the normal energizing energy is achieved by securing the normal heating time.

In such a state of controlling the energizing energy of the dot printing, even if the number of simultaneous energizing dots (m) exceeds the set value (m0) four or more times, the energizing energy amount starts from the fourth time. Is prevented, the print head itself is prevented from being heated, and the printing is not too dark.

The control state of the energizing energy amount is as follows:
If the dot printing state where the number of simultaneously energized dots (m) is equal to or less than the set value (m0) continues for three or more times, the energy is returned to the original energized energy from the third time, so that the print head is prevented from cooling down. The printing is not too light.

In the above embodiment, the printing medium is moved and the thermal head itself is fixed. However, it goes without saying that the present invention can be applied to a general thermal head moving type line thermal printer.

[0050]

As apparent from the above description, in the thermal printer according to the present invention, when dot printing with a large number of simultaneously energized dots continues several times, the thermal print head is heated by controlling the energizing energy amount. Therefore, the thermal print head itself is kept at an appropriate temperature. Therefore, good print quality can be obtained without shading or blurring of characters output on the print medium surface. In addition, there is an advantage that the energy efficiency is improved due to the limitation of the amount of energized energy, and the downsizing of the power supply is achieved.

[Brief description of the drawings]

FIG. 1 is a plan view of a tape printing type thermal printer shown by opening a storage cover of a tape cassette storage section.

FIG. 2 is a plan view illustrating a state where a tape cassette is stored in a cassette storage unit.

FIG. 3 is a block diagram illustrating a control system of the tape printing type thermal printer.

FIG. 4 is a flowchart of a printing energizing amount control program by the thermal printer.

FIG. 5 is a diagram illustrating a control state of the energizing energy amount of the print dot and a control state of the energizing time for controlling the energizing amount based on the flowchart.

FIG. 6 is a diagram illustrating an example of characters printed on a print medium surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tape printing type thermal printer 9 Thermal head 40 CPU 42 RAM 44 Pulse motor drive circuit 45 Pulse motor 47 Thermal head drive circuit

Claims (1)

(57) [Claims] An electric energy is sequentially and selectively applied to heating elements arranged in rows in a direction intersecting the relative movement direction of the thermal print head while moving the thermal print head and a print medium relative to each other based on print information. To determine whether the number of heating elements to which the energizing energy is simultaneously applied is m (m is an integer of 1 or more) or more. 1 determination means, and the number of prints determined to be m or more by the first determination means is n
(N is an integer of 2 or more) second determining means for determining whether or not the number is continuous, and when the second determining means determines that the number is continuous, power is supplied to each heating element in the subsequent printing. A thermal printer comprising: an energization control unit that reduces an amount of energy.