JPS58188960A - Thermal printer - Google Patents

Abstract

PURPOSE:To keep an element being scanned for printing constant temperature and to eliminate nonuniform printing, by making electric conduction to a stating heat generating element for a print scanning longer time than that to following printing, and applying one or plural printing pulses during conduction to the element at the following printing. CONSTITUTION:The arithmetic processing unit CPU of a thermal printer controls the processing of print data from an input means to output electric conduction data to the heat generating element of a thermal head TH from terminals 1- 7 and the 1st data on the start of a print scanning from a terminal 8. A logical circuit which inputs the 1st data from the terminal 8 and the print data from the terminals 1-7 of the CPU outputs a conducting strobe signal ST. Further, the print data from the terminals 1-7 of the CPU are compensated by a compensating register R2 and applied to a conducting register R3, whose output is supplied to the header TH. Then, the conduction to a starting heat generating element is made longer than the following conduction by the signal ST, and in the following printing, a short print pulse is used for feeding the elements.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a thermal head provided with a heat generating element to apply electricity to the thermal head to cause the heat generating element to generate heat, thereby applying a desired pattern onto a thermal recording paper, or by causing the heat generating element to generate heat. The present invention relates to a thermal printer that uses a thermal transfer ink ribbon to transfer heat-melt ink onto recording paper in a desired pattern to print.

The thermal head of a thermal printer has a line print head in which heating elements of the number of dots required for the printing width are arranged in a horizontal line, and a line printing head in which several heating elements are arranged in a vertical line or a matrix of several heating elements in the vertical and horizontal directions. There are serial print heads that print by moving the thermal head between the two.

An example of a thermal head is shown in FIG. The thermal head shown in FIG. 1 is an example of a head with seven elements in a vertical row for thin film serial printing.

In FIG. 1, a heat insulating layer 102 made of glass or the like is formed on a ceramic substrate 101, and a resistor 103 made of TaN or the like is formed thereon. Resistor 1
A conductor layer 104 (aluminum, gold, etc.) is formed on the other lead wire parts except for the heating resistor part 103a on 03, and only the 1 heating resistor part 103a has a high resistance value.For example, 105-1 When a current is passed between the common C and the common C, only the uppermost heating resistor portion 103M-1 is heated. 106 is a heat sink, which is used to prevent heat accumulation in the ceramic substrate.

A thermal printer presses a thermal head as shown in Figure 1 onto thermal recording paper or presses it onto the recording paper via a thermal transfer ink ribbon, and when the head comes to a desired position while moving the thermal head or recording paper. Then, a desired heating element of the thermal head is energized to generate heat, thereby coloring the thermal recording paper, or printing is performed by transferring the heat-melting ink on the thermal transfer ink ribbon to the recording paper in a desired pattern.

As is clear from the structure of the thermal head above, the thermal head has a certain amount of heat capacity, and printing is performed using the heat generated by energizing the heating element, so printing starts at the temperature of the heating element on the thermal head. It is difficult to keep the ml constant from start to finish, and as printing progresses, heat accumulates in the thermal head, increasing print density.
Print density unevenness occurs.

An object of the present invention is to reduce uneven print density by keeping the temperature of the thermal head heating element of the thermal printer as described above constant.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an explanation will be given using an embodiment of a real printing type thermal transfer printing thermal printer according to the present invention.

In the thermal transfer thermal printer, as shown in the second factor, a printing paper 3 is arranged between the thermal head 1 and the platen 2, and a thermal transfer ink ribbon 4 is arranged between the printing paper 3 and the printing head l. - While moving the thermal head 1 to the direction indicated by the arrow A in Fig. gJ2, a print signal is sent to the thermal head 1 at a predetermined printing position, and the desired heating element on the thermal head 1 is energized to generate heat for thermal transfer. The ink 4b on the ink ribbon 4 is transferred and printed onto the printing paper 3 in a desired pattern.

Fig. 3 shows a side section of a thermal transfer printer using the present invention. Guide shaft 11 suspended horizontally on the side
The lower surface of the carriage 10 is slidably guided by a guide rail 12. Carry 91
The lower end of the arm 14 is rotatably supported on a part of the arm 10m of the vehicle 0 via a shaft 13. A multiple head 15 is attached to the upper end of the arm 14 on the side facing a platen, which will be described later.

For example, a stepping motor 16 for driving an ink ribbon is attached to the lower surface of the carriage 10, and a gear 17 fixed to its output shaft and a gear 18 meshing with the stepping motor 16 are attached to the lower surface of the carriage 10.
The shaft 19 for driving the ink ribbon is rotated through the ink ribbon to freely run the ink ribbon. This stepping motor 16 naturally acts together with the carriage 10.

On the other hand, a motor 21 for driving the carriage]0 is fixed on the printer side via a bracket 20, and a pinion gear 22 identified on its output shaft meshes with a gear 23, and this gear 23 has a pulley 24. is fixed.

Corresponding to this pulley 24, another pulley (not shown) is provided on the printer side, and a drive belt 25 is stretched between these pulleys.

This drive belt 25 is formed endlessly, and a part of the arm 10a of the carriage 1G is fixed to a part of it via a connector 26. When the belt 25 is operated by the motor 21, the carriage 10
It is configured to move.

An ink ribbon cassette 27 is detachably mounted on the carriage 10. This ink ribbon cassette 27
The details will be described later.

A platen 28 is horizontally suspended opposite the carriage 10, a paper guide 29 is provided surrounding the platen 28, and a printing paper 30 is inserted between the paper guide 29 and the platen 28. The paper guide 29 is attached to a rotating arm 31, and this rotating arm 31 is connected to the shaft 3.
2, and a spring 33 stretched between one end of the bracket 20 and the bracket 20 side provides the ability to rotate counterclockwise in FIG. A pinch roller 34 is attached to the rotating arm 31, and the printing paper 30 is guided to a position facing the thermal head 15 by the pinch roller 34.

As shown in FIG. 4, a solenoid 35 is attached near the arm 14, and when the solenoid 35 is energized during printing, its plunger moves forward, causing the arm 14 to move in the clockwise direction in FIG. direction to press the thermal head 15 against the platen 28 side.

FIG. 5 shows a plan view of the printer. In FIG. 5, the carriage 10 is shown moving to the left end and moving to the right end at the same time, but in reality there is only one carriage. Also, in FIG. 5, the ink ribbon cassette 27 is not attached to the carriage lO that has moved to the left end, but the ink ribbon cassette 27 is attached to the carriage that has moved to the right end.

When printing, the carriage 10 has a full head 1! S
, the ink ribbon cassette 27, and their driving members are held and pressed against the thermal head 1s and the platen 28, and the guide F axis 11° is directed by the guide rail 1242 to move parallel to the platen 28 in the direction of arrow B.

FIG. 6 shows a cross-sectional view of an ink ribbon cassette. The cassette case is a cassette case, and an ink ribbon winding lead 36 and a supply reel 37 are attached to the cassette case. The unwound ink repo YS8 is attached to guide rollers 39 to 42.
It is attached to the winding reel 36 and guided to the winding reel 36. An opening 27b is formed at the tip of the cassette case 27, and the ink ribbon 38 is guided to pass through the open end of the opening 27b. 15 is fitted into this open U portion 27b. Also cassette case 2
A driving roller 43 is provided in the vicinity of the two 9-rules 36.
Guide rollers 44 and 45 are provided at both ends of Jl,
An ink ribbon drive belt 46 is stretched around these rollers. The drive belt 46 is elastically in contact with the ink ribbon 38 wound around the take-up reel 36 and the supply reel 37. The drive roller 43 is rotated by a shaft 19 to which driving force from the stepping motor 16 is transmitted, and the ink ribbon 38 is sent out as the drive belt 44 runs.

FIG. 7(a) shows the characters rAJ, I'BJ, in the thermal transfer printing thermal printer of the present invention configured as described above.
This is a timing chart when printed. First, the carriage drive motor 21 is started, and the carriage starts moving as shown at 200 in the figure. When the carriage starts up, stable running cannot be achieved immediately due to the acceleration of the carriage drive motor 21 and the elongation of the drive belt 25, so it is desirable to make a short run-up. When the thermal head 15 becomes stable, printing of the first character rAJ is started.

In the case of the letter type Y of rAJ, the first
In the row, from the top of the heating element of Thermal Hept 15, 4 to 7
In the second row, 2nd, 3rd, 5th!
However, in the 3rd column, Nos. 1 and 3 are in the IJ4 column, and in the IJ4 column, Qin 2, 3, etc.
No. 5 is energized, and in the fifth column, Nos. 4 to 7 are energized, and printing of the characters rAJ is completed.

As shown in the figure, the energization pulse has the energization time 202
311Iji pulses of m, 202b, and 203 are set. If the heating element at printing timing 350 in the figure is not energized at the immediately preceding dot printing timing 351, the second heating element of the thermal head 15 is cold, as shown at 204-2 in the figure, and the printing If only the pulse 202a is applied, the heating element does not generate enough heat. Therefore, when energizing a heating element that was not energized for printing at the previous printing timing, a correction energization 202b is applied to the heating element within one dot printing timing 310 following the printing pulse 202a. In this corrected energizing reef 2, the heat generation temperature can be raised to a temperature different from that in other cases, as shown at 355 in the figure.

As shown at 352 in the figure, the immediately preceding printing timing 31
When energization is performed at 0, heat is accumulated in the heating element as shown in 356 shown in the fifth heating element temperature 204-5 of the thermal head 15, so unlike the case of 350 described above, energization is performed only with energization pulses of 202 m. The desired heating element temperature can be obtained as shown at 357.

Now, if we look at the printing at 350 in the figure in a little more detail, at the printing timing 310 just before that, the fourth to seventh elements of the heating elements of the thermal head 15 are energized, and the heat generated is transferred to the third one by thermal conduction within the thermal head 15. The heat is transmitted to the second element, and the heat accumulation shown at 358 in the figure occurs also in the second element. However, in the first printing after the start of the print scan shown at 360 in the figure, there is no heat conduction from other heating elements as described above, so the energization pulse zoz as shown at 350 is generated.
When energizing a+zozb, as shown by the broken line 361, a data processing time corresponding to a sufficient heating element temperature is required, so even if print timing 310 is used in a negative manner, the data processing time 362 becomes a loss time for energization. −
It has been confirmed that when the non-current-carrying part 362 enters during the printing of dots, the heat generation efficiency decreases, which is thought to be due to temporary heat dissipation during heating, as shown at 363 in the figure, and the lack of heat generation becomes even greater. ing.

In the present invention, as a method to solve the insufficient heat generation of the heating element of the thermal head 150, the dots printed at the first leading print timing after the start of print scanning are energized at 3 in the figure.
This is done by one energization pulse 203 as shown by the solid line 60. Further, the first energization pulse 203 is the longest energization pulse compared to the other energization pulses 202m and 202b, and is the one that sufficiently heats the heating element.

Figure 7-) Haf-? #toy F 15 (7) J 1~
The heating elements up to I 7 are independently captured, and the first printing energization after the start of printing scanning on each heat-generating confectionery is performed with the same energization pulse of 20.
3, and is a method that is one step more advanced than the method shown in FIG. 7(a). In the case of the embodiment shown in FIG. 7(b), after the above operation, when printing of the - line is completed, the carriage 10
is returned to the initial position at a high speed, and the next line is scanned in the same manner. After the start of scanning of this line, the first printing energization is also conducted in the form of a -pulse in the same manner as described above.

FIG. 188 is a block diagram of a control circuit for generating energizing pulses as shown in FIGS. 7(a) and (b), and FIG. 5 is a timing chart illustrating the operation of the control circuit shown in the figure.

The CPU is an arithmetic processing unit that manages data processing related to printing, and includes input means such as a keyboard (not shown).
In addition to the print data input from
Output from.

Further, from the terminal 8, a signal of "1" is output only for the first print scan start data. CG is a character generator for generating a character font corresponding to the character data of print data, and R1 stores energization data to the heating element ratios 1 to S47 of the thermal head 15 output from terminals 1 to 7 of the CPU. In the shift register, figure 189 (
The energization data is input in synchronization with the timing pulse TPI as shown in C) and is output as a timing signal f3. R2 is an energization correction register that stores the energization data output from the shift register R1 and inverted by the inverter INV. and operates in synchronization with the timing signal ρ4.

Further, R3 is an energization register for storing energization data outputted from the left register R1. AND5
is an AND gate, the first input terminal always receives a signal of "1", the second input terminal receives the energization data from the shift register R1, and the third input terminal receives the energization data from the shift register R1. Inverted energization data from the energization correction register R2 is input to the terminal. F F1 is a foot-flop that is set and reset according to the signal state from the terminal 8 of the CPU, and operates in synchronization with the timing signal TP1. F
F2 is a Fujitsubu flop that is set and reset depending on the output state from the flip-flop FFI and operates in synchronization with the timing signal y1. 081.082 is a pulse oscillator that outputs an energizing pulse as shown in FIG. 9(1) in synchronization with the timing signal Da1.

ANI)2 is the output number o of the flip-flop)F2
AND gate ANi)3 outputs the energizing pulse from the pulse oscillator 081 when ssvv is in the IOJ state, and ANi)3 outputs the energizing pulse from the pulse oscillator 082 when the output signal ossw of the flip-flop FF2 is in the "1" state. It is an and gate. AND6 is an AND gate that outputs a uniform timing data 2 as shown in FIG. It is an AND gate that outputs the timing data 4 as shown in Fig. 9 Φ) in the state of .ORI is an AND gate, AND2.

OR gate that outputs the output from AND3 as the energizing strobe signal 8T, OR2 is AND6)
, AND7 is an OR gate that outputs the output from AND7 as a timing signal f3.

AND4 indicates that the energization data output from register R3 is “
1", the AND gate group outputs the energizing strobe signal 8T from ORI, AMP is the amplifier that amplifies the output from the AND gate group AND4, and TH is the 7 heating elements arranged in a vertical line as described above. These are thermal heads lined up.

Next, the operation of the control circuit configured as described above will be explained, taking as an example the case where a character rAJ consisting of 5 dots horizontally by 7 dots vertically is to be printed. First, from input means such as a keyboard (
(not shown) When print data is input to the CPU, the CPU extracts a character font corresponding to the character code of the print data from the character generator CG, and conducts electricity corresponding to the dot information in the first column via the data bus DB. Data is input to shift register R1 which has parallel input terminals. As mentioned above, the energization data output from terminals 1 to 8 of the CPU is an 8-bit parallel output, of which energization data for the heating elements of the thermal head, 1st to 7th, are input from terminals 1 to 7. , a signal in which only the print scan start data is "1" is output from the terminal 8. Further, the output from terminal 8 is sent to Fujitsubu flop FFI.

Therefore, the energization data from the CPU is the timing signal T[1
The shift register R1 is synchronized with the data bus DB.
and is input to Fujitsubu flops FFI and FF3 (see Fig. 9 (b1500). The energization data input to the shift register R1 is sent to the energization register R3 in synchronization with the timing signal DA3 and is inverted by the inverter INV. is stored in the energization correction register R2 (Fig. 9(b)
)501).

However, the energization correction register R2 is operated in synchronization with the timing signal D4. The energization data sent to the energization register B-3 is ANDed with the energization strobe signal 8T by an AND4 and sent to the thermal head to perform heat-generating printing. The energization strobe signal 8T operates in synchronization with a timing signal 9'l (print timing signal) and is generated from the pulse oscillators 081 and 082. The pulse oscillator 081 generally oscillates an energization pulse pattern, and the pulse oscillator 082 oscillates the energizing pulse pattern (long time - same energizing) at the start of printing scan, and the CPU
Blip-flop FF based on energization data from terminal 8 of
Ant game using the output signal ossw of I, FF2)
The energizing pulses output from the pulse oscillators 081 and 082 are selected by ND2°λNDB and the OR gate ORI. In other words, in this case, C is the print scan start data.
Since the signal whose output state is "1" is output from the terminal 8 of the PU, the output of the flip flop FF2 becomes "1", the AN-03 is opened, and the energizing pulse output from the pulse oscillator 082 is Strobe signal 8T is sent to AND gate ANI) 4 to start printing scan. The first energization is of a long-time, round-trip type (Fig. 9 (C) 502#ffi After the printing energization is started, the next The energization data corresponding to the dot information in the second column is output from terminals 1 to 7 of the CPU to the data bus DB (IF49 diagram (Jl) 503
(see 504 in FIG. 9(b)) and is input to the Vbutton register R1 in synchronization with the timing signal TP1 (see 504 in FIG. 9(b)). After the current energization data, the state of the signal output from terminal 8 of the CPU will be rOJ until - printing scans are completed.
The strobe signal is generated by the pulse oscillator 081. The energization data input to the shift register R1 is again sent to the energization register R3 in synchronization with the timing signal f3, and the second column is energized (see FIG. 9(b)).
. As in the previous case, the energization data is inverted and stored in the energization correction register R2 via the inverter INT, and is also sent to the controller AND5 without passing through the inverter IN.

Ant game) AND5 is 3-man power, and 1 of the other input terminals
Ill is always input to one terminal, and the output of the energization correction register R2 is coupled to the remaining input terminal. Timing signal 03. Both signals 1'4 and 1'4 are generated from the timing signal DA2, and the timing signals DA3 and DA4 are completely synchronized at time 505 in FIG. 9. The data input from the correction register R2 to the AND gate AND5 is data obtained by inverting the energization data from - times before.
"11" is set for the bzt that was not energized. And Antogame) did not energize the previous time with the AND5 output,
The energization correction data in which the bit to be energized this time is set to "1" is obtained and inputted into the shift register R1 again. Then, when the timing signal Da 3 occurs next (Fig. 9-) (
C) 506 reference) Energization correction data is energization register R3
The correction energization is not performed on the heating element of the thermal head that was energized at the previous timing, and the current is applied to the heating element that was not energized last time (Fig. IJ9 (cl.
(Refer to 506) Reduction correction energization is performed. Therefore, the letter “A”
9(C) shows the current pulses applied to the heating elements of the thermal head according to the second column of print data constituting ".".

From then on, based on the print data in the third to fifth columns, the energizing pulses to the heating elements of the thermal head are controlled as described above, and become as shown in Figure 19 (e). As explained above, in the thermal printer of the present invention, the first energization of the heating element in the printing scan applies a printing pulse that is longer than the energization time in the second printing, and Since the energization is applied one or more half-A key printing pulses that are shorter than the energization time, it is possible to obtain a print with a stable constant density from immediately after the start of the print scan to the end of the print scan. .

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining the structure of a thermal head, Fig. 2 is a diagram explaining a printing method of an embodiment of a thermal transfer printer used to explain the present invention, and Figs. 3 and 4 are illustrations of an embodiment of the present invention. FIG. 5 is a plan view of an embodiment of the present invention; FIG. 6 is a diagram showing the structure of an ink ribbon of a thermal transfer printer used in the present invention; FIGS. Timing chart diagrams for explaining the present invention; FIG. 8 is a block diagram showing the configuration of a control circuit for generating the energizing pulse shown in FIG. b) and (C) are timing charts explaining the operation of the control circuit shown in FIG. 8, where CPtJ is an arithmetic processing unit, R1 is a shift register,
R2 is an energization correction register, and ost and osz are pulse oscillators. Applicant Canon Co., Ltd.

Claims (1)

[Claims] In a thermal printer that uses a thermal head equipped with a heating element and prints a pattern such as a desired character on a recording paper using the heat generated by energizing the head, the heating element is heated at the beginning of a print scan. The thermal printer applies electricity to the heat generating element in subsequent printing by applying a printing pulse that is longer than the energization time in subsequent printing.