JPH082655B2 - Edge type thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an end face type thermal printer in which a heat generating portion is provided in the vicinity of an end face on the trailing end side in the printing direction of a print head.

[Prior Art] Conventionally, a thermal printer provided with a thermal head has been used. This thermal printer has the features that the printed characters are beautiful and that the sound when printing is quiet.

On the other hand, in recent years, the viscosity of the ink layer of the ink ribbon that is thermally melted by the heat generating part of the thermal head has been strengthened, and even if an incorrect print is made, the same ink ribbon peels off and erases the characters on the print paper (lift-off correction). There is also a thermal printer that can do this. In the thermal printer capable of performing the lift-off correction, a so-called end face type thermal head is used in which a heat generating portion is located in the vicinity of an end face distant from the trailing end side in the printing direction of the print head toward the minute printing direction side. . As a result, the ink ribbon is peeled off from the paper before the temperature of the ink ribbon thermally melted by the heat generating portion is lowered, and the thermally melted ink ribbon is transferred onto the paper.

[Problems to be Solved by the Invention] However, the end face type thermal printer using the end face type head has the following problems.

That is, when printing is performed using an ink ribbon having an ink layer with a high viscosity, in order to obtain high quality aptitude printing, the heated ink ribbon is printed on the paper at a constant high temperature before the temperature is lowered. Need to be stripped from. Here, as conditions for peeling the ink ribbon at a constant temperature, the amount of heat generated by the heat generating portion is constant, the transfer speed of the thermal head (that is, the printing speed) and the heat generating portion of the head from the heat generating portion to the rear end side in the printing direction. Distance to end face (hereinafter referred to as end face distance)
It is desirable that the time (timing) until the ink ribbon is heated and peeled off is kept constant by keeping the above and the same constant. However, since the distance between the end faces is very small, the thermal head moves at a constant speed even though it causes considerable variations in production.
For this reason, there is a problem that the time for peeling the ink ribbon from the paper differs depending on each head, and the print quality of characters printed on the paper also differs.

The end surface type thermal printer of the present invention is made in order to solve the above problems, and is configured as follows.

Configuration of the Invention [Means for Solving Problems] The end surface type thermal printer of the present invention has a heat-meltable ink ribbon (M1) and a rear end side in the printing direction, as shown in the basic configuration of FIG. Has a heating portion composed of an electric resistance element in the vicinity of the end face distant from the end face in the minute amount in the printing direction side, and presses the ink ribbon against the printing paper by the heating portion, and heats the ink ribbon by the heat generation portion. A print head (M2) that melts by heat and separates the ink ribbon from the print paper at the end face to perform printing, and an energizing means (M3) that energizes the heat generating portion of the print head (M2) based on print information. ) And a print head moving means (M4) for relatively moving the print head (M2) in the printing direction with the printing by the print head (M2). Printhead by motion means (M4) (M
The print head moving speed setting means (M5) for setting the moving speed of 2) according to the distance between the heat generating portion and the end face is provided.

[Operation] In the end face type thermal printer of the present invention having the above configuration, the heat-melting ink ribbon (M1) is applied to the printing paper by the heat generating portion provided near the end face on the rear end side in the printing direction of the print head (M2). By pressing, the energizing means (M3) energizes the heat generating part of the print head (M2) based on the print information to heat the ink ribbon (M1) by heat generation of the heat generating part, and further the ink ribbon (M1) at the end face. The print head moving means (M4) moves the print head (M2) in the printing direction to perform printing on the print paper, and the print head moving means (M4) moves the print head. The moving speed for moving (M2) in the printing direction is a value set by the print head moving speed setting means (M5) according to the distance between the heat generating portion and the end surface. Thereby, the end surface type thermal printer of the present invention works to move the print head (M2) at a moving speed according to the end surface distance of the print head (M2).

[Embodiment] Next, a preferred embodiment will be described with reference to the drawings in order to further clarify the configuration of the end surface type thermal printer of the present invention.

FIG. 2 is an external view of an end surface type thermal printer which is an embodiment of the present invention. A keyboard 4 is integrated in the printer unit 2, various keys such as an alphabet key 6 are provided on the keyboard 4, and a liquid crystal display 8 having a predetermined number of digits is provided so that characters, symbols, etc. entered by the keys are displayed. It is supposed to be done. The printer unit 2 prints based on the data input from the keyboard 4.

The printer unit 2 includes a carriage 10. The carriage 10 is supported by a guide bar 12 so as to be movable along the platen 14 in the x-axis direction (printing direction), and serves as a stepping motor provided on the printer frame 16 via a driving force transmission bar 18 having a spiral groove. It is driven in the x-axis direction by the configured carriage drive motor 19. Platen 14
A paper feed roller (not shown) is provided behind the paper, and is driven by a roller drive motor (not shown) provided on the frame 16 to feed the print paper 20 in the y-axis direction.

The carriage 10 has a thermal head as a print head.
22 is held, and the printing paper 20 is the thermal head.
Supplied between 22 and platen 14. Also carriage 10
A ribbon cassette 24 is removably attached to the top, and an ink ribbon 26 is attached to the thermal head 22 and printing paper.
Be routed between 20 and. During the printing operation, the thermal head 22 is pressed against the printing paper 20 via the ink ribbon 26 by a head pressing motor (not shown) provided in the carriage 10. The state at this time is shown in the top view of FIG. As shown in the figure, during the printing operation, the thermal head 22 mainly
The glaze 22 as a raised portion provided at a position distant from the end surface 22a on the trailing end side in the printing direction of 22 toward the printing direction side by a small amount 22
At the section between the heat generating portion 22c and the end surface 22a on the b side, the ink ribbon 2
6 is pressed against the printing paper 20 and the ink ribbon 26 is printed from the point P1 immediately after passing the end face 22a in the printing direction.
Peel from. The ink ribbon 26 can increase the viscosity of the ink layer that is heat-melted by the heat generating portion 22c, so that the same ink ribbon can be used to peel off and erase the characters even when printing is made by mistake.

The thermal head 22 is shown as FIG. 3 (B) when viewed from the direction of the arrow AR in FIG. 3 (A). As shown in FIG. 3 (B), the heating portion 22c of the thermal head 22 has a heating element 22d formed of an electric resistance element vertically.
It is a set of 26 pieces. Each of these individual heating elements 22d corresponds to one vertical row of dots constituting a character to be printed by being thermally transferred onto the printing paper 20.

Next, the electronic control unit 30 for controlling the end surface type thermal printer of this embodiment will be described. The electronic control unit 30 shown in FIG. 4 is provided in the printer body.

As shown in the figure, the electronic control unit 30 is a well-known CPU 30a, ROM
30b and RAM30c, etc.
d, external output circuit 30e and external input circuit 30f, etc.
As logic operation circuits connected to each other.

The external output circuit 30e includes the heat generating unit 2 of the thermal head 22 via the shift register 30h and the energization driver circuit 30i.
2c, each of which is connected to the carriage drive motor 19 via a motor driver circuit 30j, and a motor driver circuit
The head pressure bonding motor (not shown) is also connected via 30k, and the paper feed motor and the like are also connected via a motor driver circuit 30l. Here, the shift register 30h is
It has a register corresponding to the number of heating elements 22d of the heating section 22c, and sequentially outputs signals according to the pattern of characters to be printed to the energization driver circuit 30i. The energization driver circuit 30i energizes each heating element 22d according to the signal output from the shift register 30h. The signal for energizing the heating element 22d is output from the energizing driver circuit 30i when the enable signal directly output from the external output circuit 30e to the energizing driver circuit 30i becomes high level.

The external input circuit 30f of the electronic control unit 30 is connected to the keyboard 4 for inputting characters to be printed, a setting switch 35 for setting the moving speed of the thermal head 22 that moves together with the carriage 10, and the like.

One end of each of the switches S1 to S4 of the setting switch 35 is
Each of them is pulled up via a resistor R1 to R4, and the other ends thereof are both grounded. As a result, the ports P1 to P4 connected to the respective power supply sides of the switches S1 to S4 are
It shows a low level when the switch is turned on. The ports P1 to P4 are connected to the external input circuit 30f, respectively.

The operation of the present embodiment having the above-described configuration will be described with reference to the "printing control routine" shown in FIG.
The set processing routine will be described below.

The "printing control routine" shown in FIG.
It represents a process executed when a character or the like inputted by the user is printed on the printing paper 20.

When a print command is input to the CPU 30a from the keyboard 4 or the like, this process is called after the thermal head 22 is pressure-bonded to the print paper 20 via the ink ribbon 26, and the CPU 30a
First, the value of the print dot counter DC in the RAM 30c is cleared to zero (step S100). In the present embodiment, the characters to be printed are formed as a pattern of 24 dots × 24 dots, and the value of the print dot counter DC indicates which vertical row of dot patterns is printed by the heat generating section 22c.

Subsequently, the CPU 30a switches the excitation phase of the carriage drive motor 19 via the external output circuit 30e and the motor driver circuit 30j (step S110). This allows
The thermal head 22 moves in the printing direction along with the carriage 24 by one dot of the character pattern to be printed. After that, one vertical column of the character pattern to be printed is read from the ROM 30b according to the value of the dot counter DC, and the read character pattern (print data) is output to the external output circuit 30e.
And the energization driver circuit 30i via the shift register 30h
(Step S120).

When the print data is output, the subsequent steps S130 through
By the process of S160, the enable signal output from the external output circuit 30e directly to the energization driver circuit 30i is set to the high level for the set energization time T1. This energization time T1 is set in the timer circuit 30d.

By the above processing (step 130 to S160 in FIG. 5),
The energization driver circuit 30i turns on only the heating element 22d corresponding to the output print data during the energization time T1.
As a result, the ink ribbon 26 is thermally melted according to the print data.

After that, the CPU 30a timers the remaining excitation time T2 so that the overall excitation time (hereinafter referred to as phase switching time) becomes T3 from the time when the excitation phase of the carriage drive motor 19 is switched in step S110. Circuit 30d
Is set (step S170), and wait processing is performed until the excitation time T2 elapses (step S180).

The phase switching time T3 is set as follows.

The rotation speed of the carriage drive motor 19 configured as a stepping motor, in other words, the movement speed of the thermal head 22 that moves together with the carriage 10, is the phase switching time.
Determine according to T3. That is, the shorter the phase switching time,
The moving speed of the thermal head 22 becomes faster. On the other hand, from the end surface 22a of the thermal head 22 shown in FIG.
The distance (hereinafter, referred to as end face distance) l1 indicates a variation in manufacturing. On the other hand, the above processing (steps S130 to S1)
The time (hereinafter, referred to as peeling time) T from the time when the ink ribbon 26 that has been thermally melted by 60) is thermally melted to the time when the ink ribbon 26 is peeled off from the printing paper 20 is determined by the end face distance l1 and the moving speed of the thermal head 22. Determined. Here, in the present embodiment, a process of setting the moving speed of the thermal head 22 according to the end face distance l1 is performed. That is, as shown in Table 1 below, when the end face distance l1 is greater than or equal to zero and less than the predetermined value a, the switch S1 of the setting switch 35 has a predetermined value a or more and a predetermined value b or more.
When it is less than, the switch S2 is turned on in advance, when it is more than the predetermined value b and less than the predetermined value c, the switch S3 is turned on, and when it is more than the predetermined value c, the switch S4 is turned on.

The CPU 30a sets the phase switching time T3 according to the switch in the ON state, that is, the port indicating the low level. That is, as shown in the "phase switching time T3 setting processing routine" in FIG. 6, the phase switching time T3 is set to a predetermined value t1 when the port P1 is at the low level (steps S171 to S172), and the port P2 is set to the low level. At the level, the predetermined value t2 (<
t1) (steps S173 to S174), and a predetermined value t3 (<t2) when the port P3 is at low level (step S173).
On the other hand, if a negative determination is made in step S175, the port P4 is regarded as low level and set to a predetermined value t4 (<t3) (steps S175 and S177).

When a positive determination is made in step S180 shown in FIG. 5, it means that the carriage drive motor 19 is excited in a predetermined phase during the phase switching time T3.

In the following step S190, the value of the print dot counter DC is incremented, and then it is determined whether the value of the print dot counter DC is 24 (step S200). If a negative determination is made here, the process returns to step S110, and if an affirmative determination is made, it is concluded that printing of one character to be printed has ended and the process returns to "RETURN".

The timing chart shown in FIG. 7 shows the timing relationship between the phase switching signal and the energization signal to the heating element 22d when the phase switching time T3 is t1 to t4.

As described above, according to this embodiment described in detail, the end face distance l1
The moving speed of the thermal head 22 can be changed according to the value of. As a result, regardless of the difference in the end face distance l1,
This has an excellent effect that the peeling time T of the ink ribbon can be made constant at all times, and proper print quality can be obtained regardless of the difference in the end face distance l1. Further, as a result, even if the thermal heads 22 having different end face distances l1 are used due to variations in production, it is possible to always provide an end face type thermal printer having high printing quality.

Next, the end surface type thermal printer of the second embodiment will be described.

The end surface type thermal printer of the second embodiment has a setting switch 35 used in the end surface type thermal printer of the first embodiment.
And using the setting switch 35a shown in FIG.
Similarly, the "phase switching time T3 setting processing routine" shown in FIG. 9 is executed as the "phase switching time T3 setting processing routine" shown in FIG.

Here, the setting switch 35a, as shown in FIG.
One end of each of the switches Sa1 to Sa8 is pulled up via a resistor Ra1 to Ra8, and the other end thereof is grounded. The ports Pa1 to Pa8 connected to the power supply side of each of the switches Sa1 to Sa8 reach the external input circuit 30f of the electronic control unit 30.

In the end surface type thermal printer of the second embodiment, the setting switch 35a is set to the average resistance value r and the end surface distance l1 of the 26 heating elements 22d made of electric resistance elements as shown in Table 2 below. It is set based on.

When the end face distance l1 belongs to the same range value, the higher the average resistance value r is, and when the end face distance l1 belongs to the same range value, the larger the end face distance l1 is, the higher-order switch is in the ON state. It is said that For example, when the end face distance l1 is greater than or equal to the predetermined value a and less than the predetermined value b, the average resistance value r is
When it is zero or more and less than the predetermined value d, the switch Sa2 is set. When it is more than the predetermined value d and less than the predetermined value e (> d), the switch Sa3 is set.
When the value is equal to or greater than the predetermined value e and less than the predetermined value f (> e), the switch Sa4 is used. When the value is greater than or equal to the predetermined value f and less than the predetermined value g (> f), the switch Sa5 is used, and Turns on the switch Sa6.

The CPU 30a of the electronic control unit 30 shown in FIG. 4 changes the ON state of the switches Sa1 to Sa8 to each port Pa according to the processing of the "phase switching time T3 set processing routine" shown in FIG.
Detecting via 1 to Pa8, the process of setting the value of the phase switching time T3 is performed.

That is, the phase switching time T3 is set to a predetermined value ta1 when the port Pa1 is at a low level (steps S210 to S211),
When the port Pa2 is at the low level, the predetermined value ta2 is set (steps S212 to S213), and when the port Pa3 is at the low level, the predetermined value ta3 is set (steps S214 to S215), and the port Pa4 is set.
Is a low level ta4 (steps S216 to S217), and port Pa5 is a low level ta5.
(Steps S218 to S219) and when the port Pa6 is at low level, the predetermined value ta6 is set (steps S220 to S22).
1) When the port Pa7 is at the low level, the predetermined value ta7 is set (steps S222 to S223). On the other hand, when the determination in step S222 is negative, the port Pa8 is regarded as the low level and the predetermined value ta8 is set (steps S222 and S223). S224).

The end surface type thermal printer of the second embodiment has the same effects as the first embodiment and the following effects.

Normally, the heating elements 22d of the thermal head 22 are manufactured to have the same resistance value, but in manufacturing, the resistance value may vary from head to head. For example, as a measurement result, about 17
The variation of the value from 0 (Ω) to 230 (Ω) is measured. Therefore, the amount of heat generated by the heating element 22d within the same energization time T1 increases as the resistance value decreases. Therefore, the amount of heat generated by the ink ribbon 26 may differ, which may impair the print quality. Here, in the present embodiment, the process of changing the value of the phase switching time T3 according to the value of the average resistance value r of the heating element 22d is performed. This allows the ink ribbon 26
Ink ribbon until it is peeled off from the print paper 20
By changing the temperature drop of 26, the printing paper 20 of the heated ink ribbon 26 is irrespective of the variation in the resistance value of the heating element 22d.
The temperature at the time of peeling from the can be constant. As a result, there is an excellent effect that high-quality printing can be performed regardless of the variation in the resistance value of the heating element 22d.

The predetermined values ta1 to ta8 are set such that the peeling time T is changed from the relationship between the end face distance l1 and the average resistance value r of the heating element 22d so that the temperature at which the ink ribbon 26 is peeled is constant. The value is preset to

Next, the end surface type thermal printer of the third embodiment will be described.

The end surface type thermal printer of the third embodiment has a tenth phase as a "phase switching time T3 setting processing routine" shown in FIG.
The "phase switching time T3 set processing routine" shown in the figure is executed.

In the end surface type thermal printer of the third embodiment, the setting switch 35a shown in FIG.
Set according to the table.

That is, as shown in Table 3, switches Sa1 to Sa4
In the same manner as in Table 1 of the first embodiment, the switch to be turned on is set by the value of the end face distance l1. Also, switch
Sa5 to Sa8 are heating elements 22d as shown in Table 4.
When the average resistance value 22d is 0 or more and less than the predetermined value d1, the switch Sa5 has a predetermined value d1 or more and the predetermined value e1 (> d1).
Switch Sa6 is greater than or equal to a predetermined value e1 and f1 (> e
When it is less than 1), the switch Sa7 is turned on, and when it is the predetermined value f1 or more, the switch Sa8 is turned on.

The CPU 30 of the electronic control unit 30 shown in FIG. 4 changes the ON state of the switches Sa1 to Sa8 to each port Pa according to the processing of the “phase switching time T3 set processing routine” shown in FIG.
It is detected through 1 to Pa8 and the value of the phase switching time T3 is set.

That is, when the port Pa1 is at the low level, the table E1 shown in Table 5 below is selected (steps S230 to S231),
When port Pa2 is low level, table E2 is selected (steps S232 to S233), when port Pa3 is low level, table E3 is selected (steps S234 to S2).
35) On the other hand, if a negative decision is made in step S234, port Pa4 is regarded as low level and table E4 is selected (step 236). After this, subsequently, when the port Pa5 is at the low level, the first data of the selected table is set as the phase switching time T3 (steps S237 to S23).
8) When the port Pa6 is at low level, the second data of the selected data is set as the phase switching time T3 (step S2
39 to S240), and when the port Pa7 is at low level, the third data in the selected table is set as the phase switching time T3 (steps S241 to S242), while step S241.
If a negative decision is made in step 4, the port Pa8 is regarded as low level and the fourth data in the selected table is set as the phase switching time T3 (step S243). This allows
In this embodiment, as shown in Table 5, the phase switching time T3 can be set in 16 levels. still,
Here, the predetermined values tb1 to tb8 of the phase switching time T3 are set to be larger as the predetermined value is smaller in the same reference table.

The end surface type thermal printer of the third embodiment has the same effect as the end surface type thermal printer of the second embodiment, and further the phase switching time T3 based on the end surface distance l1 and the average resistance value r of the heating element 22d. The effect is that it can be set precisely and the printing quality can be further improved.

The end surface type thermal printer of the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the present invention.

According to the end surface type thermal printer of the present invention, the moving speed of the end surface type thermal head can be changed according to the value of the end surface distance. As a result, the temperature of the ink ribbon when the ink ribbon is peeled off from the printing paper can be made to be the same regardless of the difference in the end face distance, and proper print quality can be obtained regardless of the difference in the end face distance. It has an excellent effect that Further, as a result, even if the end surface type thermal heads having different end surface distances are used due to variations in production, it is possible to always provide the end surface type thermal printer having high printing quality.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the basic configuration of an end surface type thermal printer of the present invention, FIG. 2 is an external view of the end surface type thermal printer of one embodiment of the present invention, and FIGS. 3 (A) and 3 (B).
FIG. 4 is an explanatory view showing the thermal head 22, FIG. 4 is an electric circuit diagram centering on the electronic control unit 30, FIG. 5 is a flow chart showing the processing of the “print control routine”, and FIG. 6 is a “phase switching time T3”. FIG. 7 is a flowchart showing the processing of the “set processing routine”, FIG. 7 is a timing chart showing the timing of the energization signal and the phase switching signal, FIG. 8 is a circuit diagram showing the setting switch 35a of the second embodiment of the present invention, and FIG. Is a flowchart showing the processing of the "phase switching time T3 setting processing routine", and FIG. 10 is a flowchart showing the processing of the "phase switching time T3 setting processing routine" executed in the third embodiment of the present invention. 2 …… Printer section 4 …… Keyboard 20 …… Printing paper 22 …… Thermal head 26 …… Ink ribbon 30 …… Electronic control unit 35,35a …… Setting switch

Claims (2)

[Claims] 1. A heat-meltable ink ribbon, and a heat generating portion composed of an electric resistance element in the vicinity of an end face distant from the trailing end side in the printing direction toward the printing direction side by a minute amount. A print head that presses the ribbon against the printing paper, heats the ink ribbon by the heat generated in the heat generating portion, and separates the ink ribbon from the printing paper at the end face to perform printing, and An end face type thermal printer comprising: energizing means for energizing a heat generating portion of a print head; and print head moving means for relatively moving the print head in a printing direction when printing is performed by the print head. End face type, characterized in that print head moving speed setting means for setting the moving speed of the print head by the means according to the distance between the heat generating part and the end surface is provided. Thermal printer. 2. The print head moving speed setting means is configured to set the moving speed of the print head according to a distance between the heat generating portion and the end face and a resistance value of the heat generating portion. The end surface type thermal printer according to claim 1.