JP3244756B2 - Printhead control device and printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Contents] Industrial application field Conventional technology (FIG. 15) Problems to be solved by the invention (FIG. 16) Means for solving the problems (FIGS. 1 to 3) Action Embodiment (1) Description of the first embodiment (FIGS. 4 to 7) (2) Description of the second embodiment (FIGS. 8 and 9) (3) Description of the third embodiment (FIGS. 10 to 14)

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head control device,
The present invention relates to a head control method and a printer, and more particularly, to an apparatus for driving and controlling a thermal head, a control method thereof, and an improvement of a printer.

[0003] In recent years, thermal printers have been used in the field of measuring instruments and medical instruments which hard copy various kinds of character information on thermal paper and image information displayed on a display device.

According to this, the head drive control circuit comprises a data processing circuit and n head drive transistors,
It controls the energization of a plurality of heating resistors uniformly.
For this reason, when performing thermal printing processing with a high printing rate in which the number of heat-generating dots is continuous, there may occur a snoring phenomenon that leads to a decrease in print quality, and in a thermal printer using the head driving method, the print quality and Reliability may be reduced.

Therefore, it is necessary to perform high-quality thermal printing processing by controlling the history of the heating resistors without uniformly controlling the current supply to the plurality of heating resistors, and to improve the reliability of the applied device. There is a need for a control device, a control method and a printer that can be achieved.

[0006]

2. Description of the Related Art FIGS. 15 and 16 are explanatory views according to a conventional example. FIG. 15 shows a configuration diagram of a thermal printer according to a conventional example.

In FIG. 15, for example, a thermal printer for thermally printing on thermal paper 29 includes a paper movement control circuit 1, a thermal head 2, a head drive control circuit 3, a motor 4,
PU (microprocessor unit) 5 and platen 6
Etc.

The thermal head 2 has a heating resistor R1.
To Rn are line-dot type linearly arranged, and the head 2 is pressed in the direction of the platen 6. As shown in the operation flowchart of the MPU 5 in the figure, the function of the thermal printer first performs data input processing in step P1. At this time, the MPU 5 sends the movement control data D2 to the paper movement control circuit 1 based on the external input data DIN.
Is output. On the other hand, the print data D1 is output to the head drive control circuit 3.

In step P2, a paper supply process is performed. At this time, the thermal paper 29 is inserted between the thermal head 2 and the platen 6, the platen 6 is driven via the motor 4, and the thermal paper 29 is sequentially fed.

At the same time, a head driving process is performed in step P3. Here, energization of the plurality of heating resistors R1 to Rn of the thermal head 2 is controlled by the head drive control circuit 3 based on the print data D1. In step P4, it is determined whether the printing process is completed.

As a result, heat is supplied to the thermal paper 29 between the thermal head 2 and the platen 6, and, for example, various character information and image information are printed on the thermal paper 29.

[0012]

According to the thermal printer of the prior art, the head drive control circuit 3 is arranged as shown in FIG.
As shown in the diagram for explaining the problem (a), a data processing circuit 3A that outputs energization times T1 to Tn based on print data DIN and a print command WE, and a thermal head based on the energization times T1 to Tn. N head driving transistors Tr1 to T for individually driving the two heating resistors R1 to Rn
rn, and the drive control circuit 3 includes a plurality of heating resistors R1
To Rn are uniformly controlled.

For this reason, when the thermal paper 29 is subjected to a thermal printing process at a high printing rate in which the number of heat-generating dots is continuous, there is a case where a snoring phenomenon which leads to a decrease in print quality may occur. here,
The snoring phenomenon is caused by the fact that one heating resistor Rn is continuously used, and the heat storage resistor Rn keeps the heat-sensitive paper, even though the head drive transistor Trn is OFF. Thermal printing is erroneously performed in 29 unintended printing areas.

The balance between the total heat storage and the total heat dissipation of the internal heating resistors R1 to Rn is determined by the inherent heat dissipation characteristics determined by the material (such as aluminum), shape and area of the entire thermal head. It is considered that, for example, when one heat generating resistor Rn is continuously used without being removed, the excess heat storage amount is locally concentrated.

FIG. 16B is a characteristic diagram for explaining the problems of the conventional example, and shows the number of times the thermal head 2 has been used versus the print density characteristics. In FIG. 16B, the print bleeding area C depends on the heat radiation characteristics of the thermal head 2. For example, when the number of continuous use of the same heating dot (a certain heating resistor Rn) becomes n = 5 or more, Is what happens.

This occurs when a plurality of heating resistors R1 to Rn are uniformly controlled by the head drive control circuit 3. For example, the print density [OD Was 0.9,
Print density [OD] gradually by using 3 or 4 times continuously
And the print density [OD] of the print bleeding area C exceeds 1.1.

As a result, it is difficult for the head drive system employing the head drive control circuit and the control method to suppress the occurrence of print bleeding or the like due to the snoring phenomenon. There is a problem that reliability is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and does not control the energization of a plurality of heating resistors uniformly, but controls the history of the heating resistors to achieve high-quality heat. It is an object of the present invention to provide a print head drive control device, a head control method, and a printer capable of performing a printing process and improving the reliability of the applied device.

[0019]

FIGS. 1 and 2 are principle diagrams (parts 1 and 2) of a print head control device according to the present invention.
FIG. 3 shows a principle diagram of a head control method and a printer according to the present invention, respectively.

As shown in FIG. 1, the first print head controller of the present invention comprises a plurality of heating elements Rn [n = 1, 2,
i, j], the drive time of the print head 16 is controlled by correcting the energization time Tn [n = 1, 2, i, j] of the heating element Rn for each heating element Rn. Head drive correction control unit Hn [n = 1, 2, 2,
i, j] are provided.

In the first print head control device, each of the head drive correction control units Hn is arranged as shown in FIG.
, At least based on the print data DIN and the print command WE, the previous print lines _Lx-1 , _Lx-2 .
m, the number of continuous heating dots of the heating element Rn driven through the print line Lx is counted, and the continuous heating number data D is calculated.
Data processing means 1 for outputting 1k [k = 1, 2, i, j]
1 and a heating value correcting means 12 for outputting a conduction time Tn (x) = TX corrected based on the continuous heating value data D1k.

The second print head control device of the present invention is the first print head control device according to the first print head control device, wherein the data processing means 11 performs the previous print line L _x-x as shown in FIG. _1, L _x-2 ... the print line Lx of the heating element Rn of driving through continuous / discontinuous heating by counting the number of dots continuous / discontinuous heating speed data D2k from Lm [k = 1,
2, i, j] is output.

Further, as shown in FIG. 2B, in the third print head control device of the present invention, in the first print head control device, each of the head drive correction control units Hn includes at least print lines _{L x-1, L x-} 2 ... print data Din1 according to Lm, second storage means for storing a first storage means 13A for storing Din2～Dinm, the print data DIN relating to the printing line Lx 13B and the energizing time T based on the print data Din1, Din2 to Dinm and DIN.
It is characterized by comprising a correction control means 14 for setting n (x) = TX.

The head control method of the present invention is similar to that of FIG.
A plurality of heating elements Rn [n = 1, as shown in FIG.
2, i, j], at least as shown in the control flowchart of FIG. 3B, first, in step P1, the energization time of the heating element Rn of the print line Lx In relation to the determination of Tn (x) = TX, the power supply time Tn is corrected based on the power supply state of the heating element Rn of the previous print line L _x−1 , L _x−2 . The energizing process of the print line Lx is performed based on the correction process.

In the head control method, a small number of
At least, the energization processing of the print line Lx
Print lines up to the previous m-th line based on IN Lx
L_x-1, L _x-2... Characterized by referring to the Lm energized state
And

Further, as shown in FIG. 3C, the printer according to the present invention comprises a paper moving means 15 for moving and supplying a paper 19.
A print head 16 for printing on the paper 19, and a head drive control unit 1 for controlling the drive of the print head 16
7, the sheet moving means 15 and the head drive control means 1
And a controller 18 for controlling the input and output of the printer 7. The printer according to claim 7, wherein the head drive controller 17 comprises the print head controller according to claim 1, 2, 3, or 4.

In the above-mentioned printer, the output of the print head 16 is controlled based on the head control method according to the fifth and sixth aspects, thereby achieving the above object.

[0028]

According to the first print head control device of the present invention, as shown in FIG.
Is provided for each of the heating elements Rn.

For this reason, as shown in FIG. 3A, the energizing time Tn (x) = TX of the heating element Rn of the print line Lx is concerned.
, The head drive correction control unit Hn corrects the power-on time Tn based on the power-on state of the heating element Rn of the previous print line L _x-1 , L _x-2 . The control can be performed by hardware.

That is, as shown in FIG. 2A, this is a case where one heating element Rn is used continuously, and based on the print data DIN and the print command WE, the previous print line Ln is used. _x-1 , L _x-2 ... Lm to the print line L
The number of continuous heating dots of the heating element Rn driven through x is counted by the data processing means 11, and the continuous heating number data D 1 k is output to the heating value correction means 12.

The heating value correcting means 12 corrects the energizing time Tn of the heating element Rn based on the continuous heating number data D1k (head history control), and the corrected energizing time Tn (x) = TX Can be output to the print head 16.

As a result, even when a thermal printing process with a high printing rate in which the number of heat-generating dots is continuous is performed, a snoring phenomenon as in the conventional example is suppressed as much as possible, and a high-quality thermal printing process can be performed. Becomes

According to the second print head control device of the present invention, as shown in FIG.
1 counts the number of continuous and discontinuous heating dots of the heating element Rn that is driven through the printing line Lx from the previous printing lines Lx _-1 , Lx _-2 . The data D2k is output to the calorific value correcting means 12.

Therefore, as compared with the first print head control device, the head drive correction control unit H is involved in determining the energization time Tn (x) = TX of the heating element Rn of the print line Lx.
n, it is possible to perform head history control for extremely finely correcting the energization time Tn based on the number of continuous and discontinuous heating dots of the heating elements Rn of the previous printing lines L _x−1 , L _x−2 . Becomes

As a result, the heating elements R1 to Rn can be controlled in the same manner as in the first print head control apparatus without uniformly controlling the power supply to the heating elements R1 to Rn as in the conventional example.
By performing the head history control described above, it is possible to perform high-quality thermal printing processing and to improve the reliability of a thermal printer or the like to which the apparatus is applied.

Further, according to the third print head control device of the present invention, as shown in FIG. 2B, each head drive correction control unit Hn stores the first and second storage means 13A, 13B and It comprises correction control means 14.

[0037] For example, print data relating to the print line of the two eyes before the print line Lx based on _{L x-1, L x- 2} Din1, Din2 are stored in the first storage means 13A. Further, based on both print data Din1 and Din2, the energization time Tn (x) = TX relating to the print data DIN of the print line Lx stored in the second storage means 13B is determined by the correction control means 14.
Is set by

Therefore, similarly to the first and second print head control devices, the determination of the energization time Tn (x) = TX of the heating element Rn of the print line Lx is performed by the head drive correction control unit Hn. it is possible to perform the printing line L _x-1, a head history control to correct the current time Tn based on the current state of the L _x-2 ... heating element Rn of Lm by software.

Thus, the first and second heating elements R1 to Rn are not uniformly controlled as in the conventional example,
Unlike the second print head control device, by performing head history control of the heating elements R1 to Rn based on a control program, it is possible to perform high quality thermal print processing, and
It is possible to improve the reliability of a thermal printer or the like to which the device is applied.

According to the head control method of the present invention,
As shown in the control flowchart of FIG. 3B, in step P1, the determination of the energization time Tn (x) = TX of the heating element Rn of the print line Lx is performed, and the previous print line Lx is determined.
Correction of the power-on time Tn is performed based on the power-on state of the heating element Rn of _x-1 , L _x-2 .

For example, in step P1, the energization time Tn (x) = TX of the heating element Rn of the print line Lx is determined while referring to the energization state of the preceding mth print line based on the print line. I do.

For this reason, by energizing the print line Lx based on the energizing time Tn (x) = TX corrected in step P2, as shown in FIG. Even when the element Rn is used continuously, the total heat storage amount and the total heat release amount of the heating elements R1 to Rn inside the device always balance, depending on the specific heat radiation characteristics of the print head 16. By performing head history control so as to maintain the heat accumulation amount, the excess heat storage amount is diverted to the other heat generating elements Ri and Rj, and the heat storage amount and the heat release amount are transferred to each other, thereby avoiding concentration.

As a result, even when a thermal printing process with a high printing rate in which the number of heat-emitting dots is continuous is performed, a snoring phenomenon as in the conventional example is suppressed as much as possible, and a high-quality thermal printing process can be performed. Becomes

According to the printer of the present invention, FIG.
As shown in (c), the paper moving means 15, the print head 1
6, head drive control means 17 and control means 18 are provided, wherein the head drive control means 17 comprises the first to third print head control devices of the present invention, and the print head 16 is provided with the head control method of the present invention. The output is controlled based on

For example, when the paper 19 is moved and supplied by the paper moving means 15 via the control means 18, the paper 19
Is thermally printed by the print head 16. At this time, the print head 16 is driven and controlled by the head drive control means 17 comprising the first, second or third print head control device of the present invention.

For this reason, the plurality of heating elements R1 to Rn are individually subjected to head history control by the first to third print head control devices of the present invention. The energizing time Tn of Rn is gradually controlled to be short, and the energizing time Tn of the heating element Rn that has been continuously stopped is longer than the other heating elements Ri and Rj. Controlled.

As a result, the amount of heat stored or radiated by the other heating element Ri or Rj and the amount of heat generated by the heating element Rn are optimally controlled, so that printing can be performed as in the conventional example. A uniform thermal printing process can be performed without easily reaching the bleeding area C.

As a result, it is possible to avoid a snoring phenomenon in which thermal printing is erroneously performed in an unintended printing area of the paper 19 as in the conventional example. Further, by adopting the print head control device and the head drive method for implementing the head control method, it is possible to provide a thermal printer with high print quality and high reliability.

[0049]

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 4 to 14 are diagrams illustrating a print head control device, a head control method, and a printer according to each embodiment of the present invention.

(1) Description of First Embodiment FIG. 4 is a block diagram of a drive control device for a thermal head according to a first embodiment of the present invention. FIG. 2 shows a configuration diagram of an apparatus for driving one of the heating resistors. FIG. 5 is a time chart for explaining the operation for correcting the energization time, and FIG. 6 is a supplementary explanatory diagram of the head history control.

FIG. 7 is a configuration diagram of a thermal printer according to each embodiment of the present invention, and shows a printer configuration diagram to which a drive control device for the thermal head is applied. For example, in the head drive control circuit for driving the thermal head 26 applicable to the thermal printer shown in FIG. 7, the head drive correction control unit H1 for driving the first heating resistor R1 is provided in FIG. It comprises a first heating dot counting circuit 21, an energy correction section 22, and a head drive transistor Tr1.

Incidentally, the head drive correction control unit H1 is arranged as shown in FIG.
A plurality of heating elements Rn [n = 1, 2, i,
j] is a control unit for driving the first heating resistor R1 in the head drive control circuit 27 for driving and controlling the thermal head 26 composed of 640 heating resistors R1 to R640 as an example. It corrects the energization time T1 of the heating resistor R1 connected to Vp.

The first heating dot counting circuit 21 is an embodiment of the data processing means 11 and, for example, based on the print data DIN and the print command WE, for example, the print line Lx
4 _x (m = 4) printing lines L _x-1 to
The number of continuous heating dots of the heating resistor Rn driven through Lx _-4 is counted and the continuous heating number data D1k [k = 1, 2, 2
i, j]. Here, m is the number of previous print lines based on the print line (FIG. 6).
(A)).

Further, the first heat generation dot counting circuit 21 includes a two-input OR circuit (hereinafter referred to as a two-input OR circuit) OR1,
Two-input AND circuit (hereinafter referred to as two-input AND circuit) AND
1, a counter 21A and a decoder 21B.

For example, the two-input OR circuit OR1 outputs a two-input OR signal to the two-input AND circuit AND1 based on the print data DIN for the print line Lx and the print command WE for the reference energization time T. Input AND circuit AND1
Outputs a two-input AND signal which becomes a clear signal CLR to the counter 21A based on the two-input OR signal and the reset signal R / S.

The counter 21A counts the print command WE based on the clear signal CLR and outputs 4-bit count data QA, QB, QC, QD to the decoder 21B. Count decoding data Q2, Q3, and Q as an example of the continuous heat generation number data D1k.
4, Q5 are connected to first to fourth energization time setting circuits TM1 to TM
4 is output.

The energy correction section 22 is a heating value correction means 1
2 is an example in which the energization time Tn (x) = TX corrected based on the continuous heat generation number data D1k is output.
For example, the energy correction unit 22 includes first to fourth conduction time setting circuits TM1 to TM4 and a four-input OR circuit (hereinafter referred to as a four-input OR circuit) OR2.

The first energization time setting circuit TM1
4 times of energizing time T1 are input based on the count decoding data Q2
This is output to the OR circuit OR2. For example, the first
The electric time setting circuit TM1 is a timer IC (semiconductor integrated circuit device).
Placement) 22A and its constant circuit r ₁, C₁Consists of
Assuming that the safety factor is 10%, T1 = 1.1 ×
r₁, C₁It is.

Note that the first energization time is set from the decoder 21B.
When the decoded data Q2 is output to the constant circuit TM1
In this case, the other count decoding data Q3, Q4, Q5
It is not output to the fourth energization time setting circuits TM2 to TM4.
Therefore, in the second to fourth energization time setting circuits TM2 to TM4,
Indicates that the count decoding data Q3, Q4, and Q5 are input.
In this case, the energization time T2, T3, T4 is ORed by 4 inputs each
Output to the circuit OR2. In addition, their energizing times T2 to T
4 is T2 = 1.1 × r_Two, C_Two, T3 = 1.1 × r _Three,
c_Three, T4 = 1.1 × r_Four, C_FourIt is.

The 4-input OR circuit OR2 outputs a control voltage for one energization time Tx output from the first to fourth energization time setting circuits TM1 to TM4 to the base of the head drive transistor Tr1 (FIG. 5 (a) to (d)).

The head driving transistor Tr1 controls the driving of the first heating resistor R1 connected to the head driving power supply Vp based on the control voltage. Thus, according to the thermal head drive control device according to the first embodiment of the present invention, as shown in FIG. 4, for example, the head drive for correcting the energization time Tx of the first heating element R1 A correction control unit H1 is provided, which comprises a first heating dot counting circuit 21, an energy correction unit 22, and a head drive transistor Tr1.

For this reason, in the case where the thermal head of one line dot = 640 dots as shown in FIG. 6A is driven and controlled, each heating element R1 of the print line Lx is controlled.
Relates to energizing time Tn (x) = TX determination of ～R640, always the head driving based on the current state of each heating element R1~R640 previous four th print line L _{x- 1} ~L _x-4 The power supply time Tx is corrected by the correction control units H1 to H640.
For example, the head history control can be performed by hardware.

That is, as shown in the supplementary explanatory diagram of the head history control in FIG. 6A, for example, the third heating resistor R
3, the heating resistor R3 is used continuously in the preceding third printing line Lx _{-1 to} Lx _-3 . In such a case, the printing data DIN and printing are performed. based on the command WE, the previous printing line L _x-1 ~L _{x- 4}
From the heating resistor R driven through the printing line Lx
The number of continuous heating dots of 3 = 4 is counted by the first heating dot counting circuit 21 of the third head drive correction controller H3, and the continuous heating number data D1k is supplied from the decoder 21B to the fourth of the energy correction circuit 22. Energizing time setting circuit TM4
Is output to

Further, in the energy correction circuit 22, the energization time Tx of the heating resistor R3 is corrected (head history control) based on the continuous heating number data D1k composed of the count decoding data Q5. Thereby, FIG. 5D and FIG. 6B
It is possible to output the corrected energization time T3 (x) = T4 as shown in FIG.

As shown in FIG. 6A, when attention is paid to the fourth heating resistor R4, the printing of the first printing line L _{x-1 to} L _x-3 is not performed. The line L _x-1 uses it, and the second and third print lines L _x-2 , L
_{In x-3} , it is not used.

[0066] If such is based on the print command WE and the print data DIN, the heating resistor is driven from the previous printing line L _x-1 ~L _x-4 through the print line Lx R4
Is generated by the first heat generation dot counting circuit 21 of the fourth head drive correction control unit H4, and the continuous heat generation number data D1k is supplied from the decoder 21B to the first to the second of the energy correction circuit 22. 4 energization time setting circuit T
It is output to one of M1 to TM4.

In the energy correction circuit 22, FIG.
As shown in (c), the energizing time Tx of the heating resistor R4 is corrected (head history control) based on the continuous heating number data D1k including the count decoding data Q3. This makes it possible to output the corrected energization time T4 (x) = T2 to the thermal head as shown in FIGS. 5C and 6B.

Thus, even when a thermal printing process with a high printing rate in which the number of heat-generating dots is continuous is performed, a snoring phenomenon as in the conventional example is suppressed as much as possible, and a high-quality thermal printing process can be performed. Becomes

Next, the thermal printer according to the embodiment of the present invention will be described while supplementing the operation of the drive control device for the thermal head of the present invention. FIG. 7 is a configuration diagram of the thermal printer according to each embodiment of the present invention. For example, a thermal printer that thermally prints on thermal paper 29, which is an example of paper 19, is shown in FIG.
A, a motor 25B, a platen 25C, a line dot type thermal head 26, a head drive control circuit 27, and a microprocessor (hereinafter simply referred to as MPU) 28. The head drive control circuit 27 is a thermal head according to each embodiment of the present invention. Of the drive control device.

That is, the paper movement supply circuit 25A, the motor
The plate 25B and the platen 25C constitute one embodiment of the sheet moving means 15, and move and supply the thermal paper 29. For example, the paper movement supply circuit 25A controls the output of the motor 21B based on the movement control data D2 from the MPU 28.

The motor 25B drives the platen 25C. The platen 25C makes the thermal paper 29 datch-roll at a predetermined position of the thermal head 26, thereby connecting the thermal print paper 29 with a predetermined printing area of the thermal paper 29. It is intended to be opposed.

A line dot type thermal head (hereinafter simply referred to as a thermal head) 26 is an embodiment of the print head 16 for performing thermal printing on a thermal paper 29 in a line shape. For example, 640 heating resistors R1 to R640 are arranged in a line, and the head 26 is pressed in the direction of the platen 25C.

The head drive control circuit 27 is an embodiment of the head drive control means 17, and the thermal head 26
Drive control. For example, the control circuit 27
FIG. 4 shows a thermal head drive control device according to the first embodiment of the present invention, that is, the first control device described above with reference to FIG.
And a 640 head drive correction control units H1 to H640 comprising a heating dot counting circuit 21, an energy correction unit 22, and a head drive transistor Tr1.

The MPU 28 is an embodiment of the control means 18 and controls the input and output of the paper movement supply circuit 25A and the head drive control circuit 27. For example, the MPU 28 outputs print data DIN and a print command WE to each of the head drive correction controllers H1 to H640.

As described above, according to the thermal printer according to the first embodiment of the present invention, as shown in FIG. 7, the paper movement supply circuit 25A, motor 25B, platen 25C, thermal head 26, head drive control circuit 27, an MPU 28, and the head drive control circuit 27 comprises a drive control device for a thermal head according to the first embodiment of the present invention;
The thermal history of the thermal head 26 is controlled.

For example, when the thermal paper 29 is moved and supplied by the paper movement supply circuit 25A, motor 25B and platen 25C via the MPU 28, the thermal paper 29 is thermally printed by the thermal head 26. At this time, the drive control of the thermal head 26 (head drive control circuit 27) according to the first embodiment of the present invention controls the drive of the thermal head 26.

For this reason, the 640 heating resistors R1 to R640 are individually subjected to head history control by the thermal head drive control device according to the first embodiment of the present invention. Energizing time T3 of heating element R3
With respect to (x), it is gradually controlled to be short, and the energizing time T4 (x) of the heating element R3 which has been continuously stopped
Is controlled to be longer than the other heating elements R3 and R5.

As a result, the amount of heat stored and radiated by the other heating elements R3 and R5 and the amount of heat generated by the heating element R4 are optimally controlled to be balanced, as in the conventional example. A uniform thermal printing process can be performed without easily reaching the printing bleed area C.

This makes it possible to avoid a snoring phenomenon in which the thermal printing is erroneously performed in an unintended printing area of the thermal paper 29 as in the conventional example. Further, by adopting the print head control device and the head drive method for implementing the head control method, it is possible to provide a thermal printer with high print quality and high reliability.

(2) Description of the Second Embodiment FIG. 8 is a configuration diagram of a drive control device for a thermal head according to a second embodiment of the present invention. FIG. FIG. 9 shows supplementary explanatory diagrams of the head history control.

The difference from the first embodiment is that in the second embodiment, the continuation of the heating element Rn driven from the previous printing line L _x−1 , L _x−2 . And a second heat generation dot counting circuit 31 for counting the number of non-continuous heat generation dots and outputting continuous / non-continuous heat generation number data D2k [k = 1, 2, i, j].

That is, the second heating dot counting circuit 31
Is another embodiment of the data processing means 11, and based on the print data DIN and the print command WE, for example, the fifth print line L (m = 5) based on the print line Lx.
_{x-1 to} Lx _-5
It counts the number of discontinuous heat generation dots and outputs continuous / non-continuous heat generation number data D2k [k = 1, 2, i, j] (see FIG. 9A).

For example, the second heating dot counting circuit 31 includes a two-input OR circuit OR3, first to fifth two-input AND circuits (hereinafter referred to as two-input AND circuits) A1 to A5, an up / down counter 31A, and a decoder 31B. Consists of

The two-input OR circuit OR3 is connected to the print line Lx
Command WE for print data DIN and reference energization time T according to
Up / down counter 31 based on
A. The up / down counter 31A counts the print command WE based on the two-input OR signal and the reset signal R / S serving as the clear signal CLR, and outputs 4-bit count data QA, QB, QC, and QD.
B.

Further, the decoder 31B converts the decoded data Q2, Q3, Q4, Q5, and Q6, which are examples of the continuous / non-continuous heat generation number data D2k, into first to fifth two-input A
These are output to the ND circuits A1 to A5. Also, the first
The two-input AND circuits A1 to A5 respectively include the print data DIN and the count decoding data Q2 and Q2 related to the print line Lx.
2, Q4, Q5, Q6, and two inputs AN respectively.
The D signal is output to the first to fifth conduction time setting circuits TM1 to TM5 of the energy correction circuit 32.

The functions of the energy correction circuit 32
5 is the same as that described with reference to FIG.
Energization time T5 set by the interval setting circuit TM5 = 1.1
× r _Five, C_FiveIncrease. Thus, five energization times
T1 to T5 are first to fifth conduction time setting circuits TM1 to T
It is output from M5 to a 5-input OR circuit OR4.

As a result, the control voltage for one energization time Tx output from the first to fifth energization time setting circuits TM1 to TM5 is output from the 5-input OR circuit OR4 to the base of the head drive transistor Tr1.

As described above, according to the drive control apparatus for the thermal head 26 according to the second embodiment of the present invention, FIG.
As shown in the figure, the second heating dot counting circuit 31
From the first print line L _{x-1 to} L _x-5 to the print line L
x, the number of continuous / non-continuous heating dots of the heating element Rn driven through x is counted, and the continuous / non-continuous heating number data D
2k is output to the energy correction circuit 32.

For example, one line as shown in FIG.
= 640 dots in the case where the thermal head of the printing line Lx is driven and controlled.
The energization time Tn (x) = relates to the determination of the TX, always print lines before 5 knots L _x-1 ~L each heating element of the _x-5 R1
When the head drive correction controllers H1 to H640 correct the power-on time Tn (x) based on the power-on state of R640 to R640,
It is possible to perform the head history control.

That is, as shown in the supplementary explanatory diagram of the head history control in FIG. 9A, the first to fifth, 639, and 640th heads are controlled.
Heating resistors R1 to R5, R639 and R640
Each continuous in the print line L _x-1 ~L _x-5 in /
Consider the case of non-continuous use. In this case, on the basis of print data DIN and the print command WE (see FIG. 8), before 5
Heating resistor from the printing line L _x-1 ~L _x-5 to the eye to the continuous / discontinuous driven through the print line Lx R1
-Number of continuous / non-continuous heating dots of R5, R639 and R640 =
1 to 3 are head drive correction control units H1 to H5, H639, H
640, and the result of the counting ( continuous / non-continuous heating number data D
2k ) is output to any one of the first to fifth conduction time setting circuits TM1 to TM5 of the energy correction circuit 32.

The energy correction circuit 32 generates heat.
Continuous / non-continuous heat generation number data D from the dot counting circuit 31
Based on 2k (decoded data Q2 to Q6 of the decoder 31B) , the respective energization times T1 (x) to T5 (x), T639 (x) and T640 (x) of the heating resistors R1 to R5, R639 and R640 are determined. , T
1 (x) = TX + 1, T2 (x) = TX-1, T3 (x) = TX +
3, T4 (x) = TX + 1, T5 (x) = TX + 1, T639 (x) =
TX-3 and T640 (x) = TX-1 are corrected (head history control). Here, “+” appended after TX
“1”, “−1”, “+3”, and “−3” are heating dot meters.
Counting of up / down counter 31A in number circuit 31
Value change, that is, as shown in FIG.
Starting from the count value (initial setting value TX) at the print line L _x-5
Of the count value of the up / down counter 31A
Indicates the content. For example, pay attention to the first heating resistor R1.
Then, heat is generated (ON) in the _fourth print line L _x-4.
Since it is in the state, the count value increases to TX + 1, and the next
Line L _x-3 is in the pause (off) state, so the count value
Goes down to TX + 1−1 = TX, and the same
Make-up / down counting, in the print line L _x T1
(x) = TX + 1. Other heating resistors R2 to R5, R6
Similarly, up / down counting is performed for 39 and R640.
As a result, the power supply time is corrected as shown in FIG.
Will be In addition, the energization included in the energy correction circuit 32
The time setting circuits TM1 to TM5 are described in the first embodiment.
The energization set in each circuit is the same as (see FIGS. 4 and 5).
TM1>TM2>TM3>TM4> TM5
Have a relationship. Further, in this embodiment, for example, the setting is made by TM1.
That correspond to the above TX based on the energization time
Then, the energization time set by TM2 is equal to TX + 1.
The energization time set in TM3 corresponds to TX + 2
The energization time set in TM4 corresponds to TX + 3,
The energization time set by TM5 corresponds to TX + 4. Reverse
In addition, the above T
Assuming that it corresponds to X, the energization time set by TM4
Interval corresponds to TX-1, and the energization time set in TM3 is
The energization time set in TM2 corresponds to TX-2.
-3, the energization time set by TM1 is TX-4
Corresponding to

The heating resistors R1, R2, R5,
For R639 and R640, since there is no print command WE for the print line, the corrected energization time T1 (x) = TX +
1, T2 (x) = TX-1, T5 (x) = TX + 1, T639 (x) =
TX-3 , T640 (x) = TX-1 is the next history information.

The heating resistors R1, R2, R5,
For R639 and R640, since there is no print command WE for the print line, the corrected energization time T1 (x) = TX +
1, T2 (x) = TX-1, T5 (x) = TX + 1, T639 (x) =
TX + 1, T640 (x) = TX + 1 is the next history information.

As a result, as shown in FIG. 9B, the energy correction circuit 32 for the heating resistors R3 and R4 is used.
Time T3 (x) = TX + 3, T4 (x) =
TX + 1 can be output to the thermal head.

As a result, the first heating element R1 to R640 does not need to be energized uniformly as in the prior art.
In the same manner as in the embodiment, even when the thermal printing process is performed at a high printing rate in which the number of generated heat dots is continuous, the snoring phenomenon as in the conventional example is suppressed as much as possible, and the high-quality thermal printing process can be performed. It becomes possible. In addition, it is possible to improve the reliability of a thermal printer or the like to which the apparatus is applied.

(3) Description of Third Embodiment FIG. 10 is a block diagram of a drive control device for a thermal head according to a third embodiment of the present invention, and is a configuration of a device for driving a plurality of heating resistors. FIG. FIGS. 11 and 12
FIG. 13 is a control flowchart (Nos. 1 and 2) of FIG.
14 shows supplementary explanatory diagrams (parts 1 and 2) of the head history control.

The difference from the first and second embodiments is the third embodiment.
In the embodiment of the present invention, the heating element R driven from the _second printing line L _x-1 and L _x-2 through the printing line Lx is used.
A head drive control circuit 37 for monitoring the state of the continuous heating dots 1 to R640 and controlling the correction of the energization times T1 (x) to T640 (x) for each of the heating resistors R1 to R640 is provided.

That is, the head drive control circuit 37 comprises 640 head drive correction units H1 according to the first and second embodiments.
To H640, a first random-access memory (hereinafter simply referred to as RAM1) 23A,
(Hereinafter simply referred to as RAM2) 23B, print set register 23C, MPU 24, and drive transistor group 37A.

The RAM 1 constitutes a part of the first storage means 13A. For example, the RAM 1 always stores the print data Din2 of the preceding second print line Lx _{-2 based on} the print line Lx. Is what you do. The RAM 2 has the first
And a part of the storage means 13A.
Based on the printing line Lx, always, and stores the print line L _x-1 of the print data Din1 before the first run.

The print set register 23C is an embodiment of the second storage means 13B and temporarily stores the print data DIN of the print line Lx. When the printing process of the first line is completed, the printing data DIN of the printing line Lx is shifted to the RAM 2 when the printing process of the first line is completed, and becomes the printing data Din1 of the preceding first printing line Lx _-1 . When the print processing of the second line of the print data Din1 is completed, the data Din1 is shifted to the RAM 1 and becomes the print data Din2 of the previous second print line Lx _-2 .

[0102] MPU24 is an embodiment of the correction control unit 14, print line before two first L _{x- 2,} L _x-1 of the print data Din2, Din1 energizing time according to the printing line Lx based on the Tn ( x) = TX is set.

The driving transistor group 37A is composed of 640 driving transistors Tr1 to Tr640 for individually controlling the switching of the 640 heating resistors R1 to R640 constituting the thermal head 26. For example, the 640 heating resistors R1 to R640 are individually driven on the basis of the control voltages output from the MPU 24 for the optimal energization times T1 (x) to T640 (x).

As described above, according to the drive control apparatus for the thermal head 26 of the third embodiment of the present invention, as shown in FIG.
C, an MPU 24 and a head drive control circuit 37 composed of a drive transistor group 4 are provided.
By monitoring the state of the continuous heating dots 1 to R640, correction control of the energization times T1 (x) to T640 (x) is performed for each of the heating resistors R1 to R640.

[0104] For example, print data according to the printing line L _x-1, L _{x- 2} of 2 knots before with respect the print line Lx Din1, Din2 are stored in RAM 1, RAM 2. Further, based on the two print data Din1 and Din2, the energizing time Tn (x) = Tn related to the print data DIN of the print line Lx.
X is set by the MPU 24.

Therefore, as in the first and second embodiments, the energizing time Tn (x) of the heating element Rn of the print line Lx is equal to
In connection with the determination of TX, the head drive control circuit 37 causes the heating resistors R1 to R1 of the previous second print lines Lx _-1 and Lx _-2.
Optimal energizing time T1 (x) to T based on the energizing state of R640
The head history control for correcting 640 (x) can be performed by software.

As a result, unlike the first and second embodiments, the 640 heating resistors R1 to R640 are not uniformly controlled as in the conventional example, and the heating resistors R1 to R640 are controlled based on a control program. By controlling the head history of .about.R640, it is possible to perform high-quality thermal printing processing and to improve the reliability of a thermal printer or the like to which the apparatus is applied.

Next, a head control method according to the present invention will be described.
Description will be made while supplementing the operation of the head drive control circuit 37. FIGS. 11 and 12 are control flowcharts (parts 1 and 2) of the thermal head according to the third embodiment of the present invention. FIGS. 13 and 14 are supplementary explanatory diagrams (parts 1 and 2) of the head history control. Each is shown.

For example, when the head history control of the 640 heating resistors R1 to R640 as shown in FIG. 10 is performed by software, first, in FIG. 11, an initial setting process is performed in step P1. The initial setting process at this time is performed in RAM1, RAM2
And clears the print set register 23C and sets the energization reference time T of the thermal head 26.

Next, at step P2, the print line Lx
Of the print data DIN according to the above. At this time, for example, print data in which the first line L1 as shown in FIG. 13 (a) is all pause dots (white circles) and the second line L2 becomes heat-generating dots (black circles) It is assumed that DIN is input.

Thereafter, in step P3, the print line L
It is determined whether or not a print command WE related to x has been input. At this time, if the print command WE has been input (YES), the program shifts to Step P4. If not (NO), the process waits for a print command WE in step P3.

Therefore, if the print command WE has been input in step P3 (YES), the print data DIN for the print line Lx is written in step P4.
Here, since the subject to be compared is determined after the third line after the head drive control circuit 37 starts the printing process, the printing process is started and reaches three lines for convenience of explanation. Assume that

Thereafter, in step P5, the print line L
Prior to determining the energizing time Tn (x) = TX for x
1 and the print data Din1 and Din2 of the RAM 2 are read out. At this time, as shown in FIG. 13A, for example, the print data Din1 of the previous second print line L1 is read from the RAM 1 with reference to the print line L3. Further, the print data Din2 of the preceding first print line L2 is read from the RAM 2 with reference to the print line L3. Further, the print data DIN of the print line L3 is temporarily stored in the print set register 23C.

In steps P6 to P12, the energizing time T1 (x) = TX for the first heating resistor R1 is determined, and in steps P13 to P19, the energizing time T2 ( x) = T is determined, and similarly, steps P20-P
The energizing time T640 (x) for the 640th heating resistor R640 at 26
= TX is determined. At this time, based on the print data Din1 and Din2 of the previous second print lines L1 and L3, the energizing times T1 (x) to T640 (x) for the print line L3 are set to MP.
It is set by U24.

That is, the print data Din1 stored in the RAM1 in step P6 is "1" indicating a heating dot (hereinafter, RAM1 = "1") or "0" indicating a pause dot. (Hereinafter referred to as RAM1 = “0”) is determined. At this time, RAM1 =
If "1" (YES), the program shifts to Step P7.
If RAM1 = "0" (NO), the program shifts to Step P10.

Therefore, if it is "1" indicating a heating dot (YES), the print data Din2 stored in the RAM 2 in step P7 is "1" indicating a heating dot, or if it is paused. A determination process of “0” indicating a dot is performed. At this time, if RAM2 = “1” (YES), the flow shifts to Step P8. Also, it is RAM2 =
If "0" (NO), the process shifts to Step P9.

If RAM1 = “0” in step P6 (NO), the print data Din2 stored in RAM2 in step P10 is “1” indicating a heating dot, or it is a pause dot. Is determined as “0”, which indicates At this time, if RAM2 = “1” (YES), the flow shifts to Step P11. Also, it is RAM2 =
If "0" (NO), the program shifts to Step P12.

Therefore, the contents of steps P8, P9, P11 or P12 are selected by the print data Din1 stored in the RAM1, the print data Din2 stored in the RAM2, and the print data DIN of the print line Lx.

For example, RAM1 and RAM2 are both "1".
In step P8, the energizing time T1 (x) = T-2α of the print line Lx is set in step P8. If the RAM1 is "1" and the RAM2 is "0", the process proceeds to step P9.
Sets the energizing time T1 (x) = T (reference energizing time T) for the print line Lx.

Further, if the RAM 1 is "0" and the RAM 2 is "1", the printing line Lx
Is set to T1 (x) = T-α, and RAM
When both the RAM 1 and the RAM 2 are “0”, the energizing time T1 (x) = T + 2α of the print line Lx is set in step P12. Table 1 summarizes the state of the print data and its correction value, where T is the reference energizing time and α is the correction coefficient.

[0120]

[Table 1]

Further, as shown in FIG. 13B, the pause dot for suspending the printing process is set in the print set register 23C.
When “0” is written, the printing process of the printing line Lx is not performed, so that it is undefined.

Similarly, history control is executed in steps P13 to P19 for the energization time T2 (x) = TX for the second heating resistor R2. That is, in step P13, R
A determination process is performed to determine whether the print data Din1 stored in AM1 is "1" indicating a heating dot or "0" indicating a pause dot. At this time, RAM1
If "1" (YES), the program shifts to Step P14. If RAM1 = "0" (NO), the program shifts to Step P17.

Therefore, if it is "1" indicating a heating dot (YES), the print data Din2 stored in the RAM 2 in step P14 is "1" indicating a heating dot, or it is paused. A determination process of “0” indicating a dot is performed. At this time, if the RAM2 is "1" (YES), the flow shifts to Step P15. Also, it is RAM2 =
If "0" (NO), the program shifts to Step P16.

If RAM1 = “0” in step P13 (NO), the print data Din2 stored in RAM2 in step P17 is “1” indicating a heating dot, or it is a pause dot. Is determined as “0”, which indicates At this time, if RAM2 = “1” (YES), the flow shifts to Step P18. Also, it is RAM2 =
If "0" (NO), the program shifts to Step P19.

Therefore, the contents of step P15, P16, P18 or P19 are selected by the print data Din1 stored in the RAM1, the print data Din2 stored in the RAM2, and the print data DIN of the print line Lx.

For example, both RAM1 and RAM2 are "1".
In step P15, the energizing time T2 (x) = T-2α of the print line Lx is set in step P15. If RAM1 is "1" and RAM2 is "0", step P16
Sets the energization time T2 (x) = T (reference energization time T) for the print line Lx.

If the RAM 1 is "0" and the RAM 2 is "1", the printing line Lx
Is set to T2 (x) = T-α, and RAM
If both RAM1 and RAM2 are "0", the energizing time T2 (x) = T + 2α of the print line Lx is set in step P19.

Similarly, the flow shifts to FIG. 12, and the history control is executed in steps P20 to P26 for the energization time T640 (x) = TX for the 640th heating resistor R640. That is, the print data D stored in the RAM 1 in step P20
A determination process is performed to determine whether in1 is “1” indicating a heating dot or “0” indicating a pause dot. At this time, if RAM1 = “1” (YES), the flow shifts to Step P21. If RAM1 = "0" (NO), the program shifts to Step P24.

Therefore, if it is "1" indicating a heating dot (YES), the print data Din2 stored in the RAM 2 in step P21 is "1" indicating a heating dot, or if it is paused. A determination process of “0” indicating a dot is performed. At this time, if RAM2 = “1” (YES), the flow shifts to Step P22. Also, it is RAM2 =
If "0" (NO), the program shifts to Step P23.

If RAM1 = "0" in step P20 (NO), the print data Din2 stored in RAM2 in step P24 is "1" indicating a heating dot, or it is a pause dot. Is determined as “0”, which indicates At this time, if RAM2 = “1” (YES), the flow shifts to Step P25. Also, it is RAM2 =
If "0" (NO), the process shifts to Step P26.

Therefore, the contents of step P22, P23, P25 or P26 are selected by the print data Din1 stored in the RAM1, the print data Din2 stored in the RAM2, and the print data DIN of the print line Lx.

For example, both RAM1 and RAM2 are "1".
In step P22, the energizing time T640 (x) = T-2α of the print line Lx is set in step P22. If the RAM1 is "1" and the RAM2 is "0", the process proceeds to step P23.
Sets the energization time T640 (x) = T (reference energization time T) for the print line Lx.

If the RAM 1 is "0" and the RAM 2 is "1", the printing line Lx
Is set as T640 (x) = T−α, and the RAM
If both RAM1 and RAM2 are "0", the energizing time T640 (x) = T + 2α of the print line Lx is set in step P26.

Next, the thermal head 26 is driven based on the energization times T1 (x) to T640 (x) corrected in step P27. At this time, 640 drive transistors Tr1 to Tr640
The switching control of the 640 heating resistors R1 to R640 constituting the thermal head 26 is individually performed by the driving transistor group 37A composed of. For example, the 640 heating resistors R1 to R640 are individually driven by the driving transistor group 37A based on the control voltages related to the optimal energization times T1 (x) to T640 (x) output from the MPU 24.

Thereafter, in step P28, it is determined whether or not the head history control of the thermal head 26 has been completed. At this time, if the head history control does not end (NO), the process returns to step P2 and returns to step P2.
Step P27 is continued.

Further, the head history control is completed (YES)
Ends the printing process. Thus, according to the head (history) control method according to the third embodiment of the present invention,
As shown in the control flow charts (Nos. 1 and 2) of FIGS. 11 and 12, in Steps P6 to P26, the current print line Lx is referred to while the energized state of the previous two print lines is referred to based on the print line Lx. 640 heating elements R1 to R
The power supply time T1 (x) to T640 (x) of 640 is determined.

For this reason, by energizing the print line Lx based on the energizing times T1 (x) to T640 (x) corrected in step P28, as shown in FIG. Even when the heating elements Rn are continuously used, the total heat storage amount and the total heat dissipation of the heating elements R1 to R640 in the thermal head 26 always depend on the specific heat radiation characteristics of the thermal head 26. By performing head history control so as to maintain equilibrium, the excess heat storage amount is dissipated to other heating elements Ri and Rj, and the heat storage amount and the heat release amount are transferred to each other, thereby avoiding the concentration. .

For example, as shown in FIG. 14A, if the printing process is started and four lines have been reached,
In step P5, the energization time Tn related to the print line L4
Prior to determining (x) = TX, read processing of print data Din1 and Din2 from RAM1 and RAM2 is performed.

At this time, as shown in FIG. 14A, for example, based on the print line L4, the print data Din1 of the second previous print line L2 = “10011... 01”
Is read from the RAM 1. In addition, the printing line L
4, the print data Din2 = “01101... 00” of the previous first print line L3 is read from the RAM2. Further, the print data DIN of the print line L4
= “11100... 11” are temporarily stored in the print set register 23C.

As a result, the energizing time of the first heating resistor R1 of the print line L4 is T1 (x) = T, and the energizing time of the second and third heating resistors R2 and R3 is T2 (x), T3 (x) = T
−α is set, and the 639th and 640th heating resistors R
639, R640 energization time is T639 (x), T640 (x) = T + 2
α is set. The fourth and fifth heating resistors R4,
The energization times T4 (x) and T5 (x) of R5 are undefined.

As shown in FIG. 14 (b), if it is assumed that the printing process has started and five lines have been reached, the energizing time Tn (x) for the printing line L5 is determined in step P5.
Prior to the determination of = TX, read processing of print data Din1 and Din2 from RAM1 and RAM2 is performed.

At this time, as shown in FIG. 14B, for example, based on the print line L5, the print data Din1 of the previous second print line L2 = “01101... 00”
Is read from the RAM 1. In addition, the printing line L
The print data Din2 = “11100... 11” of the preceding first print line L4 is read out from the RAM 2 with reference to 5. Further, the print data DIN of the print line L5
= “10111... 00” is temporarily stored in the print set register 23C.

As a result, the energizing time of the first heating resistor R1 of the printing line L5 is T1 (x) = T-α, and the energizing time of the third heating resistor R3 is T3 (x) = T-2α. Is set, and the energization time of the fourth heating resistor R4 is T4 (x) =
T + 2α is set. Further, the fifth heating resistor R5
T5 (x) = T is set, and the second, 639,
640 heating resistors R2, R639, R640 energization time T2
(x), T639 (x) and T640 (x) are undefined.

As shown in FIG. 14 (c), if it is assumed that the printing process has started and six lines have been reached, the energizing time Tn (x) for the printing line L6 is determined in step P5.
Prior to the determination of = TX, read processing of print data Din1 and Din2 from RAM1 and RAM2 is performed.

At this time, as shown in FIG. 14C, for example, with reference to the print line L6, the print data Din1 of the previous second print line L2 = “11100... 11”
Is read from the RAM 1. In addition, the printing line L
6, the print data Din2 = “10111... 00” of the previous first print line L5 is read from the RAM 2. Further, the print data DIN of the print line L5
= “00000... 00” is temporarily stored in the print set register 23C.

As a result, the first to first print lines L6
The energization times T1 (x) to T of the 640th heating resistors R1 to R640
640 (x) are all undefined. From this, even in the case of performing the thermal printing process of a high printing rate in which the number of heat-generating dots is continuous, the snoring phenomenon as in the conventional example is suppressed as much as possible, and it is possible to perform the thermal printing process of high quality. .

In the embodiment of the present invention, the print data of the print line Lx is DIN = “00000... 00”.
In the case of etc., the case where all of the energization times T1 (x) to T640 (x) are undefined has been described. May be.

[0148]

As described above, according to the first print head control device, the head drive correction control unit for correcting the energization time is provided for each heating element.

For this reason, the head drive correction control unit performs the hardware control of the head history based on the energization state of the heating element of the previous print line in connection with the determination of the energization time of the heating element of the print line. Becomes possible.

Further, according to the second print head controller of the present invention, the data processing means counts the number of continuous and discontinuous heating dots of the heating element driven from the previous printing line through the printing line, The continuous / non-continuous heat generation number data is output to the heat generation amount correction means.

Therefore, as compared with the first print head control device, the determination of the energization time of the heating element of the print line concerned is based on the number of continuous and discontinuous heating dots of the heating element of the previous print line. This makes it possible to perform head history control for minutely correcting the energization time.

Further, according to the third print head control device of the present invention, each head drive correction control section comprises first and second storage means and correction control means. Therefore, the first
Similar to the print head control device of No. 2 above, it is possible to perform software control of head history based on the energization state of the heating element of the previous print line in relation to the determination of the energization time of the heating element of the print line. Becomes

According to the head control method of the present invention,
In connection with the determination of the energization time of the heating element of the print line, the energization time is corrected based on the energization state of the heating element of the previous printing line.

For this reason, by performing printing processing on the print line based on the corrected energization time, even when one heating element is used continuously, the history control of the print head can be performed. By doing so, the excess heat storage amount and the like are transferred to another heating element, thereby avoiding the concentration.

As a result, even when a thermal printing process with a high printing rate in which the number of heat-generating dots is continuous is performed, a snoring phenomenon as in the conventional example is suppressed as much as possible, and a high-quality thermal printing process can be performed. Becomes

Further, according to the printer of the present invention, there are provided a paper moving means, a print head, a head drive control means and a control means, and the head drive control means is provided with the first to third print head control devices of the present invention. The output of the print head is controlled based on the head control method of the present invention.

For this reason, with the first to third print head control devices of the present invention, the energizing time of the heating element used continuously is controlled to be short gradually, and the heating element is continuously stopped. The heating element is controlled to have a longer energization time than the other heating elements (head history control). This makes it possible to perform a uniform thermal printing process as compared with the conventional example.

By adopting the print head control device and the head driving method for implementing the head control method, this greatly contributes to providing a thermal printer with high print quality and high reliability.

[Brief description of the drawings]

FIG. 1 is a principle diagram (part 1) of a print head control device according to the present invention.

FIG. 2 is a principle diagram (part 2) of the print head control device according to the present invention.

FIG. 3 is a principle diagram of a head control method and a printer according to the present invention.

FIG. 4 is a configuration diagram of a drive control device of the thermal head according to the first embodiment of the present invention.

FIG. 5 is a time chart for explaining an operation for correcting an energization time according to the first embodiment of the present invention.

FIG. 6 is a supplementary explanatory diagram of head history control according to the first embodiment of the present invention.

FIG. 7 is a configuration diagram of a thermal printer according to each embodiment of the present invention.

FIG. 8 is a configuration diagram of a drive control device for a thermal head according to a second embodiment of the present invention.

FIG. 9 is a supplementary explanatory diagram of head history control according to the second embodiment of the present invention.

FIG. 10 is a configuration diagram of a thermal head drive control device according to a third embodiment of the present invention.

FIG. 11 is a control flowchart (part 1) of the thermal head according to the third embodiment of the present invention.

FIG. 12 is a control flowchart (part 2) of the thermal head according to the third embodiment of the present invention.

FIG. 13 is a supplementary explanatory diagram (part 1) of head history control according to the third embodiment of the present invention.

FIG. 14 is a supplementary explanatory diagram (part 2) of head history control according to the third embodiment of the present invention.

FIG. 15 is a configuration diagram of a thermal printer according to a conventional example.

16A and 16B are a configuration diagram and a printing characteristic diagram for explaining a problem according to the conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Data processing means, 12 ... Heat generation amount correction means, 13A, 13B ... First and 2nd storage means, 14 ... Correction control means, 15 ... Paper moving means, 16 ... Thermal head, 17 ... Head drive control means, 18: control means, H1 to Hn: head drive correction control unit, Rn: heating resistor (n = 1, 2, i, j ...), D1, DIN: print data (print data related to the print line), D2 ... Motion control data, WE ... Print command, Tn ... Electrification time (n = 1,2, i, j ...), D1k ... Continuous heat generation number data (k = 1,2, i, j ...), D2k ... Continuous / Discontinuous heat generation number data (k = 1, 2, i, j
..), Tn (x) = TX... Corrected power supply time (n = 1, 2, i, j
..), Din1, Din2 to Dinm: print data relating to the previous print line, Lx: the relevant print line, Lx _-1 , Lx _{-2 to} Lm: the previous print line (m = before reference to the relevant print line) Number of printing lines).

Claims (2)

(57) [Claims] 1. A print head control device for controlling the drive of a print head having a plurality of heating elements, comprising: a plurality of head drive correction controls for respectively correcting an energization time for each of the plurality of heating elements. Wherein each of the plurality of head drive correction control units responds to a print command and print data, and includes at least two lines.
From amount corresponding previous printing line corresponding heat elements driven through the print line, less from the print line
Each time the print line was heated up to two lines before
An up / down counter that counts the number and outputs parallel multi-bit count data, and generates heat based on the count data of the up / down counter.
A decoder for outputting numerical data , and a plurality of energizing time setting circuits in which a plurality of different energizing times are set for the heating element, based on the heating number data output from the decoder. as larger the value of heat generation number of data is large energization time is shorter energization time setting circuit is selected, also the heat generation speed
Any one of the plurality of energization time setting circuits is selected so that the energization time setting circuit having a longer energization time is selected as the data value is smaller, and the output of the selected energization time setting circuit is output from the selected energization time setting circuit. A print head control device, which is supplied as a corrected energization time to a heating element. 2. A sheet moving means for moving and supplying a sheet, a print head for printing on the sheet, a head drive control means for controlling the drive of the print head, and an input of the sheet move means and the head drive control means. A printer comprising a control unit for controlling an output, wherein the head drive control unit is configured by the print head control device according to claim 1.