JP7310082B2 - Driver IC for thermal print head and thermal print head - Google Patents

Description

The present disclosure relates to a driver IC for driving a thermal printhead and a thermal printhead including the driver IC.

The thermal print head selectively drives a plurality of heat-generating portions arranged in a row at a predetermined pitch according to input print data to generate heat, for example, to print on thermal recording paper. A driver IC provided in the thermal print head is configured to apply current only to a heat generating portion that generates heat according to input print data. Thermal printheads have also been developed that perform history control that adjusts the time during which current is supplied to heat-generating portions by referring to past print data and next print data. For example, Patent Literature 1 discloses a thermal print head that performs history control.

When performing history control, it is necessary to generate a strobe signal for adjusting the energization time based on past print data and next print data, and input it to the thermal print head. For example, when performing history control to perform preheating in advance based on the next print data, a strobe signal with a pulse width for normal printing and a strobe signal with a pulse width that enables preheating even though printing does not occur are used. is entered.

Japanese Unexamined Patent Application Publication No. 2013-10200

The present disclosure has been conceived under the circumstances described above, and it is an object of the present disclosure to provide a driver IC for a thermal print head that can perform history control without inputting a plurality of types of strobe signals. Make it an issue.

A driver IC provided by the present disclosure is a driver IC for a thermal print head that selectively drives a plurality of heat generation units arranged in parallel according to input print data, and is current print data to be printed this time. and the next print data to be printed next time, and an energized state in which a current is passed through the heat generating portion based on the current print data and a strobe signal for controlling the energization time for the heat generating portion. a switch for switching between a switch that switches between a non-flowing state and a cutoff state that does not flow; a preheating signal generation unit that generates a preheating signal that shortens the energization time from the strobe signal; and a preheating unit that switches the switch based on the preheating signal in the case of "1".

According to the present disclosure, the preheating signal generator generates a preheating signal that makes the energization time shorter than that of the strobe signal. Normally, the switch is switched based on the strobe signal and the current print data. When the current print data is "0" and the next print data is "1", the switch is switched based on the preheat signal. can be switched. As a result, preheating can be performed by energization based on the preheating signal whose energization time is shorter than that of the strobe signal. Moreover, since the preheating signal is generated internally, it is not necessary to input the preheating signal from the outside. Therefore, history control can be performed simply by inputting a strobe signal from the outside.

Other features and advantages of the present disclosure will become more apparent from the detailed description below with reference to the accompanying drawings.

1 is a plan view showing a thermal printhead equipped with a driver IC according to a first embodiment of the present disclosure; FIG. FIG. 2 is a plan view of the main part of the thermal print head shown in FIG. 1; FIG. 2 is a cross-sectional view taken along line III-III of FIG. 1; 2 is a cross-sectional view of the main part of the thermal print head shown in FIG. 1; FIG. 2 is a circuit diagram showing the circuit configuration of a driver IC according to the first embodiment; FIG. 4 is a circuit diagram showing a circuit configuration of a drive control section; FIG. 4 is a timing chart showing each signal of the driver IC; FIG. 5 is a circuit diagram showing a circuit configuration of a modified example of the preheating signal generator; It is a timing chart which shows each signal of the modification of a preheating signal production|generation part. FIG. 5 is a circuit diagram showing a circuit configuration of a driver IC according to a second embodiment of the present disclosure; FIG. It is a circuit diagram showing a circuit configuration of a drive control unit according to the second embodiment. FIG. 11 is a circuit diagram showing the circuit configuration of a drive control section according to a third embodiment; FIG. 11 is a timing chart showing each signal of the driver IC according to the third embodiment; FIG. It is a circuit diagram which shows the circuit structure of the drive control part which concerns on 4th Embodiment. FIG. 11 is a timing chart showing each signal of the driver IC according to the fourth embodiment; FIG. FIG. 11 is a plan view of a main part showing a thermal print head according to a fifth embodiment of the present disclosure; FIG. 17 is a cross-sectional view of main parts along line XVII-XVII in FIG. 16;

Preferred embodiments of the present disclosure will be specifically described below with reference to the drawings.

<First Embodiment>
1 to 7 show a thermal printhead equipped with a driver IC according to the first embodiment of the present disclosure. The thermal printhead A1 of this embodiment includes a first substrate 1, a protective layer 2, a conductive layer 3, a resistor layer 4, an insulating layer 18, a driver IC 6, a second substrate 5, a connector 59, and a heat dissipation member 8. there is The thermal print head A<b>1 is incorporated in a printer that prints on a print medium (not shown) conveyed while sandwiched between it and the platen roller 91 . Such printing media include, for example, thermal paper for producing bar code sheets and date code sheets.

FIG. 1 is a plan view showing the thermal print head A1. FIG. 2 is a plan view of the main part showing the thermal print head A1. FIG. 3 is a cross-sectional view along line III-III of FIG. FIG. 4 is a cross-sectional view of the main part showing the thermal print head A1. FIG. 5 is a circuit diagram showing the circuit configuration of the driver IC 6. As shown in FIG. FIG. 6 is a circuit diagram showing the circuit configuration of the drive control section. FIG. 7 is a timing chart showing each signal of the driver IC6. 1 and 2, the protective layer 2 is omitted for convenience of understanding. In FIG. 2, for convenience of understanding, a protective resin 71, which will be described later, is omitted. In these figures, the longitudinal direction (main scanning direction) of the first substrate 1 is defined as the x direction, the lateral direction (sub-scanning direction) is defined as the y direction, and the thickness direction is defined as the z direction. 1 and 2 (the right side in FIGS. 3 and 4) is the upstream side where the print medium is sent, and the upper side in FIGS. 1 and 2 (the right side in FIGS. 3 and 4) left) is the downstream side where the print medium is ejected. The same applies to the following figures.

A first substrate 1 supports a conductive layer 3 and a resistor layer 4 . The first substrate 1 has an elongated rectangular shape with the x direction as the longitudinal direction and the y direction as the width direction. Although the size of the first substrate 1 is not particularly limited, as an example, the thickness of the first substrate 1 is, for example, about 0.5 to 1 mm. The x-direction dimension of the first substrate 1 is, for example, about 50 to 100 mm, and the y-direction dimension is, for example, about 1 to 5 mm.

In this embodiment, the first substrate 1 is made of a single crystal semiconductor, such as Si. As shown in FIGS. 3 and 4, the first substrate 1 has a first substrate main surface 11 and a first substrate rear surface 12. As shown in FIGS. The first substrate main surface 11 and the first substrate back surface 12 face opposite sides in the z-direction and are parallel to each other. The first substrate main surface 11 is the surface facing upward in FIGS. 3 and 4 . The first substrate rear surface 12 is a surface facing downward in FIGS. 3 and 4 .

Moreover, as shown in FIGS. 3 and 4, the first substrate 1 has a convex portion 13 . The convex portion 13 protrudes from the first substrate main surface 11 in the z-direction and extends in the x-direction. Also, the convex portion 13 is formed on the downstream side in the y direction. The first substrate 1 is formed, for example, by forming a mask layer on the (100) plane of a single crystal semiconductor material such as a Si wafer and performing anisotropic etching. The top portion left by the mask layer and the sloped portion etched become the convex portion 13 . In this embodiment, anisotropic etching is performed twice, so that each inclined portion has two inclined surfaces with different inclinations. The angle formed by each inclined surface with the top portion is a predetermined angle according to the anisotropic etching. A portion parallel to the back surface 12 of the first substrate, which is exposed by the anisotropic etching, becomes the main surface 11 of the first substrate. Therefore, the top portion of the projection 13 and the first substrate main surface 11 are (100) planes.

As shown in FIG. 4, the insulating layer 18 covers the main surface 11 and the projections 13 of the first substrate, and in order to insulate the first substrate 1 from the resistor layer 4 and the conductive layer 3 more reliably. belongs to. The insulating layer 18 may be formed in the region of the first substrate 1 where the resistor layer 4 or the conductive layer 3 is formed. The insulating layer 18 is made of an insulating material such as SiO ₂ , SiN or TEOS (tetraethyl orthosilicate). In this embodiment, the insulating layer 18 is TEOS. In addition, the material of the insulating layer 18 is not limited. The thickness of the insulating layer 18 is not particularly limited, and an example thereof is 5 μm to 15 μm, preferably 5 μm to 10 μm.

The resistor layer 4 is supported by the first substrate 1 via the insulating layer 18 . Resistor layer 4 covers at least part of first substrate main surface 11 and projection 13 . The resistor layer 4 has a plurality of heat generating portions 41 . The plurality of heat generating units 41 locally heat the print medium by selectively energizing each of them. In the present embodiment, the heat generating portion 41 is a region of the resistor layer 4 exposed from the conductive layer 3, and is an inclined portion of the convex portion 13 (more specifically, an inclined surface on the downstream side in the y direction connected to the top portion of the convex portion 13). ). Note that the heat generating portion 41 may be arranged on the top portion of the convex portion 13 or another inclined portion, and may be arranged at a predetermined position on the main surface 11 of the first substrate 1 without providing the convex portion 13 on the first substrate 1 . may be The plurality of heat generating portions 41 are arranged along the x direction and are separated from each other in the x direction. The shape of the heat-generating portion 41 is not particularly limited, and in the present embodiment, it has a long rectangular shape with the y-direction as the longitudinal direction when viewed in the z-direction. Resistor layer 4 is made of TaN, for example. The thickness of resistor layer 4 is not particularly limited, and is, for example, 0.02 μm to 0.1 μm, preferably about 0.08 μm.

The conductive layer 3 is for forming a current-carrying path for energizing the plurality of heat-generating portions 41 . The conductive layer 3 is supported by the first substrate 1, and is laminated on the resistor layer 4 as shown in FIG. 4 in this embodiment. The conductive layer 3 exposes a portion of the resistor layer 4 which is to become the heating portion 41 . The conductive layer 3 is made of a metal material having a resistance lower than that of the resistor layer 4, such as Cu. The thickness of conductive layer 3 is not particularly limited, and is, for example, 0.3 μm to 2.0 μm.

As shown in FIGS. 2 and 4, in this embodiment, the conductive layer 3 has a common electrode 31, a plurality of individual electrodes 35, and a plurality of relay electrodes .

The relay electrode 38 has two belt-shaped portions 381 and a connecting portion 382 . The two strip-shaped portions 381 are strip-shaped extending in the y-direction and are spaced apart from each other. Each band-shaped portion 381 is connected to the adjacent heat-generating portion 41 . The connecting portion 382 is in the shape of a strip that connects to the ends of the two strip portions 381 opposite to the heat generating portion 41 and extends in the x direction. The relay electrodes 38 have a U-shape with the opening facing upstream in the y direction, and are arranged at equal pitches in the x direction on the downstream side in the y direction of the heat generating portion 41 .

The common electrode 31 includes a connecting portion 33 and a plurality of strip portions 32, branch portions 311, and straight portions 312, respectively. The orthogonal portions 312 are band-shaped extending in the y direction, and are arranged in plurality at equal pitches in the x direction. A branch portion 311 and two belt-shaped portions 32 are provided on the tip side (downstream side in the y direction) of each straight portion 312 . The two strip-shaped portions 32 are strip-shaped extending in the y-direction and are spaced apart from each other. Each band-shaped portion 32 is connected to the adjacent heat-generating portion 41 . The branched portions 311 are connected to the ends of the two belt-like portions 32 opposite to the heat generating portion 41 , and connected to the tip of the straight portion 312 . The connecting portion 33 is positioned on the base end side (upstream side in the y direction) of the plurality of straight portions 312 and extends in the x direction, and connects the plurality of straight portions 312 . The connecting portion 33 is connected to the connector 59 via the bonding wire 73 and the wiring of the second substrate 5, and is applied with a driving voltage.

The individual electrode 35 is a portion having a polarity opposite to that of the common electrode 31 . A plurality of individual electrodes 35 are arranged spaced apart in the x-direction, each having a band-shaped portion 36 and a bonding portion 37 . The belt-like portion 36 has a belt-like shape extending in the y direction, and is located upstream of the heat generating portion 41 in the y direction. The belt-like portion 36 is connected to the heat generating portion 41 on the tip side (downstream side in the y direction). The bonding portion 37 is provided at the y-direction upstream end portion of the strip portion 36 . Each bonding portion 37 is connected to one of output pads 68 (described later) of the driver IC 6 via a bonding wire 73 .

In the present embodiment, the straight portion 312 of the common electrode 31 is sandwiched between the strip portions 36 of the two individual electrodes 35 . The heat generating portion 41 to which one strip portion 381 of one relay electrode 38 is connected is connected to the common electrode 31 , and the heat generating portion 41 to which the other strip portion 381 is connected is connected to one of the individual electrodes 35 . there is Therefore, when the individual electrode 35 is energized, a current flows through the heat generating portion 41 connected thereto and the heat generating portion 41 connected to the heat generating portion 41 via the relay electrode 38 to generate heat. That is, the two heat generating portions 41 generate heat at the same time. The shape and arrangement of the conductive layer 3 are not limited.

The protective layer 2 is formed so as to overlap the first substrate main surface 11 and the projections 13 of the first substrate 1 and covers the conductive layer 3 and the resistor layer 4 . The protective layer 2 is made of an insulating material and protects the conductive layer 3 and the resistor layer 4 . The material of the protective layer 2 is, for example, SiO ₂ , SiN, SiC, AlN, etc., and is composed of a single layer or multiple layers thereof. The thickness of protective layer 2 is not particularly limited, and is, for example, about 1.0 μm to 10 μm.

As shown in FIG. 4, the protective layer 2 has openings 21 in this embodiment. The opening 21 penetrates the protective layer 2 in the z direction. The opening 21 exposes the bonding portion 37 of each individual electrode 35 .

The second substrate 5 is arranged on the upstream side in the y direction with respect to the first substrate 1, as shown in FIGS. The second substrate 5 has an elongated rectangular shape with the x direction as the longitudinal direction and the y direction as the width direction. The second board 5 is, for example, a PCB board, on which the driver IC 6 and the connector 59 are mounted. The second substrate 5 has a second substrate principal surface 51 and a second substrate rear surface 52 . The second substrate main surface 51 faces the same side as the first substrate main surface 11 of the first substrate 1 , and the second substrate rear surface 52 faces the same side as the first substrate rear surface 12 of the first substrate 1 . It is the surface.

A control electrode 55 is formed on the second substrate 5 . The control electrode 55 is arranged on the second substrate main surface 51 and extends in the y direction on the upstream side of the driver IC 6 in the y direction. Each control electrode 55 is connected to one of input pads (described later) of the driver IC 6 via a bonding wire 73 and connected to a connector 59 via wiring of the second substrate 5 .

A connector 59 is used to connect the thermal printhead A1 to a printer (not shown). The connector 59 is attached to the back surface 52 of the second substrate and is connected to the input pad 67 of the driver IC 6 via the wiring of the second substrate 5 and the control electrode 55 .

The driver IC 6 is for selectively driving a plurality of the heat generating portions 41, so that currents are supplied individually to the heat generating portions 41 that generate heat. A plurality of driver ICs 6 are provided according to the number of heat generating portions 41 . The energization control of the driver IC 6 follows a command signal input from outside the thermal print head A 1 via the connector 59 , the wiring of the second substrate 5 , and the control electrode 55 . The driver IC 6 is mounted on the second substrate main surface 51 of the second substrate 5 and connected to the individual electrodes 35 and control electrodes 55 via bonding wires 73 . As shown in FIG. 3, the driver IC 6 has a driver main surface 6a and a driver back surface 6b. The driver main surface 6a and the driver back surface 6b face opposite sides in the z-direction and are parallel to each other. The driver main surface 6 a faces the same side as the first substrate main surface 11 of the first substrate 1 . The driver back surface 6 b faces the same side as the first substrate back surface 12 of the first substrate 1 and faces the second substrate main surface 51 of the second substrate 5 . A plurality of input pads 67 and a plurality of output pads 68 are arranged on the driver main surface 6a.

The output pad 68 is a terminal through which a current for driving the heating portion 41 flows. As shown in FIG. 2, the output pad 68 is arranged at the downstream end in the y direction of the driver main surface 6a. Each output pad 68 is connected to the bonding portion 37 of the individual electrode 35 via a bonding wire 73 . In this embodiment, the output pads 68 are arranged in a row in the x direction.

As shown in FIG. 5, each output pad 68 is given a name for identification. In this embodiment, the driver IC 6 has 64 output pads 68, which are DO1, DO2, DO3, DO4, . One driver IC 6 controls the driving of the heating portion 41 connected to the 64 individual electrodes 35 .

The input pad 67 is a terminal to which various signals for controlling the driver IC 6 are input. As shown in FIG. 2, the input pad 67 is arranged at the upstream end in the y direction of the driver main surface 6a. Each input pad 67 is connected to the control electrode 55 via a bonding wire 73 . As shown in FIG. 5, the input pads 67 include VDD pads, GND pads, STB pads, LAT pads, SI pads, SO pads, CLK pads, and the like.

A voltage V _DD for driving the driver IC 6 is supplied to the VDD pad. A ground voltage is supplied to the GND pad. A strobe signal is input to the STB pad. The strobe signal is a signal for controlling the time during which an electric current is supplied to the heating portion 41. For example, the strobe signal is a pulse signal that has a high level during an energized period and a low level during a non-energized period. Note that the strobe signal is not limited to a pulse signal. A latch signal is input to the LAT pad. Print data is serially input to the SI pad. The print data is data corresponding to each print pixel, and is composed of a bit string of "1" indicating printing and "0" indicating non-printing. The print data is input with a high level signal of "1" indicating printing and a low level signal of "0" indicating non-printing. The SO pad is connected to the SI pad of another driver IC 6 to output print data. A clock signal of a predetermined frequency is input to the CLK pad.

5, the driver IC 6 includes a plurality of flip-flops 61, a plurality of latch circuits 62 and 63, a drive control section 65, and a plurality of switches 64. FIG.

The flip-flop 61 is a logic circuit for storing print data, and is a D-type flip-flop in this embodiment. Note that the flip-flop 61 is not limited. A plurality of flip-flops 61 are connected in series to form a shift register 610 . In this embodiment, 64 flip-flops 61 are connected in series.

The most upstream flip-flop 61 has its D input connected to the SI pad (input pad 67). The Q output of each flip-flop 61 is connected to the D input of the downstream flip-flop 61 . The Q output of the most downstream flip-flop 61 is connected to the SO pad (input pad 67). That is, in the driver IC 6, 64 flip-flops 61 are connected in series between the SI pads and the SO pads. A C input of each flip-flop 61 is connected to a CLK pad (input pad 67) and receives a clock signal. Each flip-flop 61 sequentially transfers the print data serially input from the SI pad to the flip-flop 61 on the downstream side in synchronization with the timing of the clock signal. The shift register 610 functions as a shift register that stores 64 bits of serially input print data.

The latch circuit 62 is a logic circuit used to use serially input print data as parallel data. In this embodiment, 64 latch circuits 62 are provided in accordance with the number of flip-flops 61 . Each latch circuit 62 receives and holds the data stored in the corresponding flip-flop 61 when 64-bit print data is stored in the shift register 610 . Each latch circuit 62 receives the Q output of the corresponding flip-flop 61 according to a latch signal that changes when 64-bit print data is stored in the shift register 610 .

The latch circuit 63 stores the print data held by the latch circuit 62 . In this embodiment, 64 latch circuits 63 are provided in accordance with the number of latch circuits 62 . Each latch circuit 63 receives and holds the print data held by the corresponding latch circuit 62 according to the latch signal. As a result, the print data to be printed this time (hereinafter referred to as "current print data") is stored in each latch circuit 63, and the print data to be printed next time (hereinafter referred to as "print data") is stored in each latch circuit 62. , “next print data”) is stored. A latch register 620 including each latch circuit 62 and each latch circuit 63 corresponds to the "storage section" of the present disclosure.

The drive control unit 65 controls driving of the corresponding switch 64 based on the print data (current print data) stored in each latch circuit 63 . The drive control unit 65 also has a preheating function for preheating by controlling the driving of the switch 64 in consideration of the print data (next print data) stored in each latch circuit 62 . . As shown in FIG. 6 , the drive control section 65 includes a preheating signal generating section 651 , a preheating section 654 , multiple AND circuits 655 , and multiple OR circuits 656 .

The preheating signal generator 651 is a circuit that generates a preheating signal based on the strobe signal. The preheat signal is a pulse signal with a pulse width smaller than that of the strobe signal. The pulse width of the strobe signal is set in accordance with the energization time required to bring the heating portion 41 to a printable temperature. On the other hand, the pulse width of the preheating signal is set so as to provide an energization time during which the temperature of the heat generating portion 41 is raised to a certain level even though the temperature does not reach the printable temperature. In this embodiment, the preheating signal generator 651 includes a filter circuit 652 and an AND circuit 653 .

Filter circuit 652 comprises a first order series RC circuit with one resistor and one capacitor. In the series RC circuit, one terminal of the resistor is connected to the input terminal and the other terminal is connected to one terminal of the capacitor. The other terminal of the capacitor is grounded. A connection between the resistor and the capacitor is connected to the output terminal. The filter circuit 652 slowly raises the output signal when the input signal rises from low level to high level. Also, when the input signal falls from high level to low level, the output signal is slowly lowered. That is, the filter circuit 652 transforms the input pulse signal into a transformed signal that slowly changes from low level to high level and then slowly changes from high level to low level, and outputs the modified signal. Therefore, the filter circuit 652 transforms the strobe signal input from the STB pad into a transformed signal and outputs the transformed signal.

FIG. 7 is a timing chart showing each signal of the driver IC6. FIG. 7(a) shows the waveform of the paper feed signal for controlling the rotation of the platen roller 91 that moves the print medium. When the paper feed signal is at a high level, the platen roller 91 rotates and the print medium is conveyed. On the other hand, when the paper feed signal is at low level, the platen roller 91 is stopped. At this time, printing is performed according to the print data. FIG. 7(b) shows the waveform of the strobe signal input from the STB pad. The strobe signal is synchronized with the paper feed signal, and is set so that the pulse is positioned while the paper feed signal is at a low level. FIG. 7(c) shows the waveform of the modified signal output from the filter circuit 652. FIG.

After the strobe signal rises from low level to high level at time t5, the deformation signal slowly rises from low level to high level. After the strobe signal falls from high level to low level at time t7, the deformation signal slowly falls from high level to low level. The filter circuit 652 transforms the strobe signal shown in FIG. 7(b) into a transformed signal shown in FIG. 7(c) and outputs the transformed signal.

The AND circuit 653 computes the AND of two input signals and outputs the computation result as a signal. One input terminal of the AND circuit 653 receives the modified signal output from the filter circuit 652 . A strobe signal is input to the other input terminal of the AND circuit 653 . The AND circuit 653 generates and outputs a pulse signal that is at high level only while the preheating signal is at or above a predetermined threshold (high level) and the strobe signal is at high level, and is at low level during the rest of the period. The preheating signal generator 651 outputs the pulse signal generated by the AND circuit 653 to the preheating section 654 as a preheating signal.

FIG. 7D shows the waveform of the preheating signal output from the preheating signal generator 651. FIG. Even if the strobe signal rises from the low level to the high level at time t5, the deformation signal rises slowly and does not reach the threshold immediately. When the deformation signal becomes equal to or higher than the threshold at time t6, the preheating signal rises from low level to high level. When the strobe signal falls from high level to low level at time t7, the preheat signal falls from high level to low level.

Thus, the preheating signal rises with a delay from the rise of the strobe signal from low level to high level, and falls at the same time as the strobe signal falls. Therefore, the pulse width _T2 of the preheat signal is smaller than the pulse width _T1 of the strobe signal. The waveform of the deformation signal output from the filter circuit 652 can be adjusted by the resistance value of the resistor and the capacitance of the capacitor that constitute the filter circuit 652 . Thereby, the pulse width _T2 of the preheating signal can also be adjusted. If the pulse width _T2 of the preheating signal is too close to the pulse width _T1 of the strobe signal, the temperature of the heat-generating portion 41 will rise, which may result in printing. On the other hand, if the pulse width _T2 of the preheating signal is too small, the amount of heat generated by the heat generating portion 41 is too small, so that it cannot heat much. The pulse width _T2 of the preheating signal is preferably 30% or more and 80% or less, more preferably 45% or more and 55% or less, of the pulse width _T1 of the strobe signal. In this embodiment, each parameter of the filter circuit 652 is designed so that the pulse width _T2 of the preheating signal is about 50% of the pulse width _T1 of the strobe signal.

The preheating signal generation section 651 outputs the generated preheating signal to the preheating section 654 . Note that the configuration of the preheating signal generator 651 is not limited. The preheating signal generator 651 may automatically generate a preheating signal having a pulse width smaller than that of the strobe signal. For example, filter circuit 652 may be another circuit.

8 and 9 are diagrams for explaining a modification of the preheating signal generator 651. FIG. FIG. 8 is a circuit diagram showing a circuit configuration of a modification of the preheating signal generator 651. As shown in FIG. FIG. 9 is a timing chart showing each signal of the modification of the preheating signal generator 651. As shown in FIG. In the modification, as shown in FIG. 8, the circuit configuration of the filter circuit 652 is different from that shown in FIG. In the series RC circuit of the filter circuit 652 according to the modification, one terminal of the resistor is connected to one terminal of the capacitor, and the other terminal is connected to the output terminal. The other terminal of the capacitor is grounded. A connection between the resistor and the capacitor is connected to the input terminal. In other words, the connecting positions of the capacitors are different from those shown in FIG. When the strobe signal shown in FIG. 9(a) is input, the filter circuit 652 according to the modification outputs the modified signal shown in FIG. 9(b). Then, the AND circuit 653 calculates the AND of the deformation signal and the strobe signal input from the filter circuit 652 to generate and output the preheating signal shown in FIG. 9(c). The preheating signal according to the modification is a pulse signal with a smaller pulse width _T2 with a delayed rise from low level to high level.

The filter circuit 652 is not limited to a primary circuit, and may be a secondary or higher circuit. Moreover, it is not limited to an RC circuit. The filter circuit 652 may transform the input pulse signal into a transformed signal that slowly changes from low level to high level and then slowly changes from high level to low level.

Further, the preheating signal generator 651 may generate the preheating signal by other methods instead of using the filter circuit 652 and the AND circuit 653 to generate the preheating signal. For example, the preheating signal generator 651 may include a triangular wave generating circuit or the like, and generate the preheating signal as a synthesized signal of the generated triangular wave and the strobe signal. Also, the preheating signal may be generated based on not only the strobe signal but also the print data. That is, before the timing of printing, the resistor heats up based on the preheating signal at which printing does not occur.

A preheating unit 654 is a circuit for determining whether or not to perform preheating. The preheating unit 654 determines whether or not to perform preheating based on the print data (current print data) stored in each latch circuit 63 and the print data (next print data) stored in each latch circuit 62. to judge. Specifically, in the preheating unit 654, the print data (current print data) stored in a certain latch circuit 63 is "0" and the latch circuit 62 corresponding to the latch circuit 63 stores If the print data (next print data) is "1", it is determined that preheating should be performed. The preheating section 654 outputs the preheating signal input from the preheating signal generating section 651 when it is determined that preheating is to be performed. On the other hand, when it is not determined that preheating should be performed, no preheating signal is output. In the present embodiment, as shown in FIG. 6, the preheating unit 654 stores, for each latch circuit 63, the print data input from the latch circuit 63 after being inverted by an inverter and the latch circuit 62 corresponding to the latch circuit 63. Logical AND with the print data input from . Then, the AND of the calculation result and the preheating signal is calculated and output as a signal. That is, the preheating unit 654 outputs a preheating signal when the current print data is "0" and the next print data is "1", and the current print data is "1" or the next print data is "1". is "0", it outputs a "0" signal (low level signal). The configuration of the preheating unit 654 is not limited, and the preheating unit 654 may output a preheating signal only when the current print data is "0" and the next print data is "1". Just do it.

The AND circuit 655 is a logic circuit that calculates and outputs the AND of the current print data input from the latch circuit 63 and the strobe signal. The output of the AND circuit 655 is high only while the print data input from the latch circuit 63 is "1" and the strobe signal is high. In other words, the AND circuit 655 outputs a high level signal for a period corresponding to the pulse width _T1 of the strobe signal when the current print data is "1". Note that a NOR circuit may be used instead of the AND circuit 655, and two inputs may be inputted via an inverter. Even in this case, an output with the same logic as the AND circuit 655 is possible. In this embodiment, 64 AND circuits 655 are provided in accordance with the number of latch circuits 63 .

The OR circuit 656 is a logic circuit that calculates and outputs the logical sum of the signal input from the AND circuit 655 and the signal input from the preheating section 654 . The OR circuit 656 outputs a high level when either the signal input from the AND circuit 655 or the signal input from the preheating section 654 is high level. In this embodiment, 64 OR circuits 656 are provided in accordance with the number of latch circuits 63 . Each OR circuit 656 outputs a signal corresponding to the strobe signal when the current print data stored in the corresponding latch circuit 63 is "1". As a result, a high level signal is output for a period corresponding to the pulse width _T1 of the strobe signal. In this case, the corresponding signal output from the preheating section 654 is a low level signal. On the other hand, when the current print data stored in the corresponding latch circuit 63 is "0", the signal output from the AND circuit 655 is a low level signal. Output the signal as is. Therefore, each OR circuit 656 outputs a preheat signal when the next print data is "1". In this case, a high level signal is output only for a time corresponding to the pulse width _T2 of the preheating signal. Each OR circuit 656 outputs a low level signal when the next print data is "0". The drive control unit 65 outputs the signal output from each OR circuit 656 to the corresponding switch 64 as a drive signal.

FIG. 7(e) shows a temporal change waveform of the print data (current print data) output from a certain latch circuit 63. FIG. FIG. 7(f) shows the waveform of the print data (next print data) output from the latch circuit 62 corresponding to the latch circuit 63, which changes with time. 7G shows the waveform of the AND signal output from the AND circuit 655 corresponding to the latch circuit 63. FIG. 7(h) shows the waveform of the driving signal output from the OR circuit 656 corresponding to the latch circuit 63. FIG.

During the period from time t1 to t3, the current print data is "0" (see FIG. 7(e)), so the AND signal output from the AND circuit 655 is at low level (see FIG. 7(g)). Further, since the current print data is "0" and the next print data is also "0" (see FIG. 7F), the signal output from the preheating unit 654 is also at low level. Therefore, the drive signal is at low level (see FIG. 7(h)).

Since the current print data is "0" even during the period from time t5 to t7 after the next print data becomes "1" at time t4 (see FIG. 7(e)), the AND signal output from the AND circuit 655 is at low level (see FIG. 7(g)). However, since the current print data is "0" and the next print data is "1" (see FIG. 7(f)), the signal output from the preheating unit 654 is a preheating signal (FIG. 7(d)). Therefore, the driving signal has the waveform of the preheating signal (see FIG. 7(h)).

Since the current print data is "1" in the period from time t9 to t11 after the current print data becomes "1" at time t8 (see FIG. 7(e)), the AND signal output from the AND circuit 655 is has the waveform of the strobe signal (see FIG. 7(b)) (see FIG. 7(g)). Further, since the current print data is "1" and the next print data is also "1" (see FIG. 7(f)), the signal output from the preheating unit 654 is at low level. Therefore, the driving signal has the same waveform as the AND signal (see FIG. 7(g)), that is, the waveform of the strobe signal (see FIG. 7(b)) (see FIG. 7(h)).

The switch 64 is a switch that is energized according to the drive signal input from the drive control section 65 . Each switch 64 is energized according to the drive signal output by the corresponding OR circuit 656 . Sixty-four switches 64 are provided according to the number of OR circuits 656 . In this embodiment, the switch 64 is an N-type MOSFET (metal-oxide-semiconductor field-effect transistor). Note that the switch 64 is not limited. The gate terminal of each switch 64 is connected to the output of a corresponding OR circuit 656 . The source terminal of each switch 64 is connected to the GND pad. The drain terminal of each switch 64 is connected to a corresponding output pad 68 . Each switch 64 is in an energized state in which a current flows through the output pad 68 to which the drain terminal is connected while the drive signal output from the OR circuit 656 connected to the gate terminal is high level, and the drive signal is low. During the level, a cut-off state is entered in which no current flows through the output pad 68 . Each output pad 68 is connected to the common electrode 31 via the heating portion 41 . Therefore, each switch 64 allows a predetermined current to flow through the corresponding heat generating portion 41 when in an energized state.

As shown in FIGS. 1 and 3, driver IC 6 is covered with protective resin 71 . Protective resin 71 is made of, for example, an insulating resin and is black, for example. The protective resin 71 is formed across the first substrate 1 and the second substrate 5 .

As shown in FIG. 3, the heat dissipation member 8 supports the first substrate 1 and the second substrate 5, and part of the heat generated by the plurality of heat generating portions 41 is transferred to the outside through the first substrate 1. It is for dissipating heat. The heat radiating member 8 is a block-shaped member made of metal such as aluminum, and is formed by extrusion molding, for example. In addition, the material and formation method of the heat radiating member 8 are not limited. As shown in FIG. 3 , the heat dissipation member 8 has a first support surface 81 and a second support surface 82 . The first support surface 81 and the second support surface 82 face upward in FIG. 3 and are arranged side by side in the y direction. The first substrate rear surface 12 of the first substrate 1 is bonded to the first support surface 81 . The second substrate rear surface 52 of the second substrate 5 is bonded to the second support surface 82 .

Next, operation of the driver IC 6 will be described.

According to this embodiment, the preheating signal generator 651 generates a preheating signal with a small pulse width using a strobe signal. The pulse width of the preheating signal is set so as to provide an energization time during which the temperature of the heat generating portion 41 is raised to a certain level even though the temperature does not reach the printable temperature. The preheating unit 654 outputs a preheating signal when the current print data is "0" and the next print data is "1", and when the current print data is "1" or the next print data is " 0”, it outputs a low level signal. The AND circuit 655 calculates the AND of the current print data input from the latch circuit 63 and the strobe signal and outputs the result. The OR circuit 656 calculates the logical sum of the signal input from the AND circuit 655 and the signal input from the preheating section 654 and outputs the result. Therefore, each OR circuit 656 outputs a signal corresponding to the strobe signal when the current print data stored in the corresponding latch circuit 63 is "1". As a result, a high level signal is output for a period of time corresponding to the pulse width _T1 of the strobe signal, and printing is performed. On the other hand, when the current print data stored in the corresponding latch circuit 63 is "0", each OR circuit 656 outputs the corresponding signal input from the preheating unit 654 as it is, so that the next print data is "1". If there is, output a preheat signal. As a result, a high level signal is output for a period of time corresponding to the pulse width _T2 of the preheating signal, and preheating is performed without printing. Moreover, since the preheating signal is generated by the preheating signal generator 651 based on the strobe signal, there is no need to input the preheating signal from the outside. Therefore, the driver IC 6 can perform history control simply by receiving a strobe signal from the outside.

Further, according to this embodiment, the preheating signal rises with a delay from the rise of the strobe signal from low level to high level, and falls at the same time as the strobe signal falls. In other words, the preheat signal causes heating to be performed as close as possible to the timing at which actual printing is started. As a result, it is possible to prevent the time from the completion of preheating to the actual printing from becoming longer, and to prevent the temperature of the preheated heat generating portion 41 from decreasing before the actual printing. Also, since the preheating signal is generated based on the strobe signal, it becomes a signal synchronized with the strobe signal.

Further, according to this embodiment, the pulse width _T2 of the preheating signal is about 50% of the pulse width _T1 of the strobe signal. Therefore, the heat generating portion 41 that is energized in accordance with the preheating signal can be sufficiently preheated without printing.

In this embodiment, the case where the strobe signal and the preheating signal are pulse signals has been described, but the present invention is not limited to this. The strobe signal may be a signal other than a pulse signal, and the preheating signal may be a signal other than a pulse signal. Further, in the present embodiment, the description has been given of the case where the fall timing of the preheating signal coincides with the fall timing of the strobe signal, but the present invention is not limited to this. For example, the rise timing of the preheat signal may coincide with the rise timing of the strobe signal. Further, the falling timing of the preheating signal may coincide with the rising timing of the strobe signal, or the rising timing of the preheating signal may coincide with the falling timing of the strobe signal.

Also, in the present embodiment, the case where the driver IC 6 is mounted on the second substrate 5 has been described, but the present invention is not limited to this. Driver IC 6 may be mounted on first substrate 1 . Also, the driver IC 6 may be mounted by flip-chip mounting.

Moreover, although the case where the first substrate 1 is made of a single crystal semiconductor has been described in the present embodiment, the present invention is not limited to this. The material of first substrate 1 is not limited, and may be, for example, ceramics. In this case, the insulating layer 18 is not formed on the first substrate 1, and instead, a glaze layer is formed by printing a thick film of glass paste and baking it in order to improve the adhesion of the conductive layer 3. Further, the glaze layer may have a convex portion formed at a position overlapping with the heat generating portion 41 .

Also, in the present embodiment, the case where the thermal print head A1 is a so-called thin film type has been described, but the present invention is not limited to this. The thermal print head A1 may be of a so-called thick film type.

10-17 illustrate other embodiments of the present disclosure. In these figures, the same or similar elements as in the above embodiment are denoted by the same reference numerals as in the above embodiment.

<Second embodiment>
10 and 11 are diagrams for explaining the driver IC 602 according to the second embodiment of the present disclosure. FIG. 10 is a circuit diagram showing the circuit configuration of the driver IC 602. As shown in FIG. Note that the switch 64, the output pad 68, and the like are omitted in FIG. FIG. 11 is a circuit diagram showing the circuit configuration of the drive control section 65. As shown in FIG. The driver IC 602 of the present embodiment differs from the first embodiment in that it determines whether to preheat in consideration of the print data that was previously printed (hereinafter referred to as "previous print data"). there is

As shown in FIG. 10, driver IC 602 further comprises latch circuit 66 .

The latch circuit 66 stores the print data held by the latch circuit 63 . In this embodiment, 64 latch circuits 66 are provided in accordance with the number of latch circuits 62 . Each latch circuit 66 receives and holds the print data held by the corresponding latch circuit 63 according to the latch signal. As a result, each latch circuit 66 stores the print data (previous print data) to be printed last time. In the present embodiment, a latch register 620 including each latch circuit 62, each latch circuit 63, and each latch circuit 66 corresponds to the "storage section" of the present disclosure.

The drive control unit 65 according to the second embodiment controls the print data (current print data) stored in each latch circuit 63, the print data (next print data) stored in each latch circuit 62, and each latch circuit. Preheating is determined in consideration of the print data (previous print data) stored in 66 . Specifically, the circuit configuration of the preheating section 654 is different from that of the preheating section 654 according to the first embodiment.

In the preheating unit 654 according to the second embodiment, the print data (current print data) stored in a certain latch circuit 63 is "0" and the latch circuit 62 corresponding to the latch circuit 63 is stored. When the current print data (next print data) is "1" and the print data (previous print data) stored in the latch circuit 66 corresponding to the latch circuit 63 is "0", preheating is performed. decide to do so. In the present embodiment, as shown in FIG. 11, the preheating unit 654 stores, for each latch circuit 63, the print data input from the latch circuit 63 after being inverted by an inverter and the latch circuit 62 corresponding to the latch circuit 63. Logical AND with the print data input from . Next, a logical product is calculated between the operation result and the print data input from the latch circuit 66 corresponding to the latch circuit 63 after being inverted by an inverter. Then, a logical product with the preheating signal is calculated and output as a signal. That is, the preheating unit 654 outputs a preheating signal when the current print data is "0", the next print data is "1", and the previous print data is "0". If the print data is "1", the next print data is "0", or the previous print data is "1", a "0" signal (low level signal) is output. The configuration of the preheating unit 654 is not limited, and the preheating unit 654 is configured such that the current print data is "0", the next print data is "1", and the previous print data is "0". It is sufficient if the preheating signal is output only when

Also in this embodiment, the preheating signal is generated by the preheating signal generator 651 based on the strobe signal, so there is no need to input the preheating signal from the outside. Therefore, the driver IC 602 can perform history control simply by inputting a strobe signal from the outside. Further, according to the present embodiment, the preheating unit 654 outputs a preheating signal when the current print data is "0", the next print data is "1", and the previous print data is "0". is output, and if the current print data is "1", the next print data is "0", or the previous print data is "1", a low level signal is output. When the current print data stored in the corresponding latch circuit 63 is "0", each OR circuit 656 of the drive control unit 65 outputs the corresponding signal input from the preheating unit 654 as it is. 1” and the previous print data is “0”, a preheat signal is output. As a result, a high level signal is output for a period of time corresponding to the pulse width _T2 of the preheating signal, and preheating is performed without printing.

Furthermore, according to this embodiment, even if the current print data is "0" and the next print data is "1", preheating is not performed if the previous print data is "1". Therefore, preheating is not performed when the print data alternately consists of "0" and "1". As a result, it is possible to prevent a phenomenon in which the temperature of the heat generating portion 41 is increased due to excessive preheating in such a case, and the print data is printed even though it is "0".

It should be noted that preheating may also be determined in consideration of print data to be printed two times before (hereinafter referred to as "print data two times before"). That is, the latch register 620 further includes a latch circuit that stores the print data held by the latch circuit 66, and the preheating unit 654 further stores the print data (previous print data) stored in the latch circuit. 0”, it may be determined to perform preheating.
Furthermore, past print data may be taken into consideration, and print data for controlling the adjacent heat-generating portion 41 may also be taken into consideration.

<Third Embodiment>
12 and 13 are diagrams for explaining the driver IC 603 according to the third embodiment of the present disclosure. FIG. 12 is a circuit diagram showing the circuit configuration of the drive control section 65 of the driver IC 603. As shown in FIG. 13 is a timing chart showing each signal of the driver IC 603. FIG. The driver IC 603 of this embodiment differs from that of the second embodiment in that it generates two types of preheating signals.

A circuit diagram showing the circuit configuration of the driver IC 603 is the same as the circuit diagram showing the circuit configuration of the driver IC 602 shown in FIG.

As shown in FIG. 12 , the drive control section 65 of the driver IC 603 further includes a second preheating signal generation section 657 . The second preheating signal generator 657 is a circuit that generates a second preheating signal based on the strobe signal. The second preheating signal is a pulse signal with a pulse width smaller than that of the preheating signal. The second preheating signal generator 657 is a circuit designed by changing each parameter of the filter circuit 652 in the preheating signal generator 651 . Note that the filter circuit 652 may be replaced by another circuit.

FIG. 13(a) shows the waveform of the strobe signal input from the STB pad, which is the same waveform as shown in FIG. 7(b). FIG. 13(b) shows the waveform of the modified signal output from the filter circuit 652, which is the same waveform as the waveform shown in FIG. 7(c). FIG. 13(c) shows the waveform of the preheating signal output from the preheating signal generator 651, which is the same as the waveform shown in FIG. 7(d). FIG. 13(d) shows the waveform of the second modified signal output from the filter circuit of the second preheating signal generator 657. As shown in FIG. FIG. 13(e) shows the waveform of the second preheating signal output from the second preheating signal generator 657. FIG.

As shown in FIG. 13(d), the waveform of the second modified signal is gentler than that of the modified signal shown in FIG. 13(b). Therefore, the second deformation signal rises more slowly than the deformation signal and therefore takes longer to reach the threshold. As a result, as shown in FIG. 13(e), the second preheating signal changes from rising from the low level to the high level of the strobe signal to a signal that rises later than the preheating signal and falls at the same time as the strobe signal falls. Become. Therefore, the pulse width _T3 of the second preheating signal is smaller than the pulse width _T2 of the preheating signal.

In the preheating unit 654 according to the third embodiment, the print data (current print data) stored in a certain latch circuit 63 is "0" and the latch circuit 62 corresponding to the latch circuit 63 is stored. When the print data (next print data) currently stored is "1" and the print data (previous print data) stored in the latch circuit 66 corresponding to the latch circuit 63 is "0", the preheat signal It outputs the preheating signal input from the generator 651 . Further, when the current print data is “0”, the next print data is “1”, and the previous print data is “1”, the second preheating signal generator 657 inputs 2 Output a preheat signal. In other cases, that is, when the current print data is "1" or the next print data is "0", the preheating unit 654 outputs a low level signal. A specific circuit configuration of the preheating unit 654 is not limited.

According to this embodiment, since the preheating signal and the second preheating signal are generated based on the strobe signal, there is no need to input the preheating signal and the second preheating signal from the outside. Therefore, the driver IC 603 can perform history control simply by inputting a strobe signal from the outside. Further, according to the present embodiment, the preheating unit 654 outputs a preheating signal when the current print data is "0", the next print data is "1", and the previous print data is "0". and outputs the second preheating signal when the current print data is "0", the next print data is "1", and the previous print data is "1". Each OR circuit 656 of the drive control unit 65 outputs the corresponding signal input from the preheating unit 654 as it is when the current print data stored in the corresponding latch circuit 63 is "0". Therefore, when the next print data is "1" and the previous print data is "0", each OR circuit 656 outputs a preheating signal for a period corresponding to the pulse width _T2 of the preheating signal. , a high level signal is output, and preheating is performed without printing. On the other hand, when the next print data is "1" and the previous print data is "1", each OR circuit 656 outputs the second preheat signal, and the pulse width _T3 of the second preheat signal A high level signal is output only for the corresponding time. In this case, although the temperature of the heating portion 41 is already high due to the previous preheating, it is preheated for a short period of time corresponding to the pulse width _T3 , so the preheating is performed to an appropriate temperature without printing. As a result, while preheating is properly performed, it is possible to prevent a phenomenon in which the print data is printed even though it is "0" due to excessive preheating.

<Fourth Embodiment>
14 and 15 are diagrams for explaining the driver IC 604 according to the fourth embodiment of the present disclosure. FIG. 14 is a circuit diagram showing the circuit configuration of the drive control section 65 of the driver IC 604. As shown in FIG. FIG. 15 is a timing chart showing each signal of the driver IC 604. FIG. The driver IC 604 of this embodiment differs from that of the second embodiment in that it generates two types of preheating signals. Also, the driver IC 604 differs from the driver IC 603 in the method of generating the two types of preheating signals.

A circuit diagram showing the circuit configuration of the driver IC 604 is the same as the circuit diagram showing the circuit configuration of the driver IC 602 shown in FIG.

As shown in FIG. 14, the drive controller 65 of the driver IC 604 further includes a second preheating signal generator 657 . The second preheating signal generator 657 is a circuit that generates a second preheating signal based on the preheating signal generated by the preheating signal generator 651 . The second preheating signal is a pulse signal with a pulse width smaller than that of the preheating signal. In this embodiment, the second preheating signal generator 657 has the same configuration as the preheating signal generator 651 . The second preheating signal generating section 657 may be a circuit designed by changing each parameter of the filter circuit 652 of the preheating signal generating section 651, or the filter circuit 652 may be another circuit. . Also, the second preheating signal generator 657 may have a different configuration from the preheating signal generator 651 .

FIG. 15(a) shows the waveform of the strobe signal input from the STB pad, which is the same waveform as shown in FIG. 7(b). FIG. 15(b) shows the waveform of the deformation signal output from the filter circuit 652, which is the same waveform as the waveform shown in FIG. 7(c). FIG. 15(c) shows the waveform of the preheating signal output from the preheating signal generator 651, which is the same waveform as that shown in FIG. 7(d). FIG. 15(d) shows the waveform of the second modified signal output from the filter circuit of the second preheating signal generator 657. As shown in FIG. 15(e) shows the waveform of the second preheating signal output from the second preheating signal generator 657. FIG.

As shown in FIG. 15(d), the waveform of the second modified signal is a signal obtained by modifying the preheating signal shown in FIG. 15(c). Therefore, as shown in FIG. 15(e), the second preheating signal rises with a delay from the rise of the preheating signal from low level to high level, and falls at the same time as the preheating signal falls. Therefore, the pulse width _T3 of the second preheating signal is smaller than the pulse width _T2 of the preheating signal.

The preheating unit 654 according to the fourth embodiment is the same as the preheating unit 654 according to the third embodiment, and the current print data is "0", the next print data is "1", and , and outputs the preheating signal input from the preheating signal generator 651 when the previous print data is "0". Further, when the current print data is “0”, the next print data is “1”, and the previous print data is “1”, the second preheating signal generator 657 inputs 2 Output a preheat signal. In other cases, that is, when the current print data is "1" or the next print data is "0", the preheating unit 654 outputs a low level signal.

Also in this embodiment, the same effects as in the third embodiment can be obtained.

In addition, in the third and fourth embodiments, the case where the second preheating signal is a pulse signal has been described, but the present invention is not limited to this. The second preheating signal may be a signal other than a pulse signal.

<Fifth Embodiment>
16 and 17 are diagrams for explaining the thermal print head A5 according to the fifth embodiment of the present disclosure. FIG. 16 is a plan view of the main part of the thermal print head A5, corresponding to FIG. FIG. 17 is a cross-sectional view of the main part along line XVII-XVII in FIG. 16, and corresponds to FIG. The thermal print head A5 according to this embodiment is different from the first embodiment in that it is a so-called thick film type.

The first substrate 1 according to this embodiment is made of ceramic, such as Al ₂ O ₃ . As shown in FIG. 17, the first substrate 1 has a glaze layer 19 , a conductive layer 3 , a resistor layer 4 and a protective layer 2 formed on the first substrate main surface 11 .

Glaze layer 19 is formed on first substrate main surface 11 and is made of a glass material such as amorphous glass. The glaze layer 19 is formed by printing a thick film of glass paste and then firing it. The glaze layer 19 is provided to eliminate irregularities on the main surface 11 of the first substrate to facilitate lamination of the conductive layer 3 . The glaze layer 19 comprises a heater glaze 191 , a die bonding glaze 192 , an intermediate glass layer 193 and an edge glass layer 194 .

As shown in FIG. 17, the heater glaze 191 is arranged on the first substrate principal surface 11 toward the downstream side in the y direction. As shown in FIG. 16, the heater glaze 191 has a strip shape extending in the x direction, and as shown in FIG. 17, the cross-sectional shape of the yz plane including the y direction and the z direction is an arc bulging in the z direction. ing. The heater glaze 191 is provided to press the heat-generating portion 41 of the resistor layer 4 against the thermal paper or the like to be printed.

The die bonding glaze 192 is formed on the main surface 11 of the first substrate and has a belt shape provided parallel to the heater glaze 191 at a position separated from the heater glaze 191 on the upstream side in the y direction. A die bonding glaze 192 partially supports the conductive layer 3 . The intermediate glass layer 193 covers a region sandwiched between the heater glaze 191 and the die bonding glaze 192 of the first substrate principal surface 11 and has a flat upper surface. The edge glass layer 194 covers a portion of the region on the y-direction downstream side with respect to the heater glaze 191 of the first substrate main surface 11, and has a flat top surface.

The conductive layer 3 according to this embodiment is formed on the surface of the glaze layer 19 facing away from the first substrate 1 . Conductive layer 3 is made of resinate Au to which rhodium, vanadium, bismuth, silicon, or the like is added, for example. The conductive layer 3 is formed by printing a paste of Au resinate as a thick film and then baking it. The conductive layer 3 may be formed by a thin film forming technique such as sputtering. The conductive layer 3 has a common electrode 31 and a plurality of individual electrodes 35 .

The common electrode 31 includes a plurality of band-shaped portions 32, connecting portions 33, and detour portions 34, as shown in FIG. The connecting portion 33 is arranged near the y-direction downstream end of the first substrate 1 and has a strip shape extending in the x-direction. The connecting portion 33 is formed on part of the heater glaze 191 and the end glass layer 194 , and is formed so that the downstream end in the y direction does not protrude from the end glass layer 194 . The upstream end in the y direction of the connecting portion 33 is on the heater glaze 191 , and the both end portions in the x direction are also formed so as not to protrude from the end glass layer 194 . The plurality of band-shaped portions 32 each extend from the connecting portion 33 toward the heater glaze 191 in the y direction, and are arranged on the heater glaze 191 at equal pitches in the x direction. The detour portion 34 extends in the y direction from one end of the connecting portion 33 in the x direction.

The plurality of individual electrodes 35 is for partially energizing the resistor layer 4 and is a portion having a polarity opposite to that of the common electrode 31 . The individual electrode 35 extends from the resistor layer 4 toward the drive IC 6 . The plurality of individual electrodes 35 are arranged at equal pitches in the x-direction, and each have a strip-shaped portion 36 , a bonding portion 37 and a connecting portion 39 . Each band-shaped portion 36 is a band-shaped portion extending in the y-direction and positioned between two adjacent band-shaped portions 32 on the heater glaze 191 . That is, the band-shaped portions 36 and the band-shaped portions 32 are alternately arranged in the x direction. The connecting portion 39 is a portion extending from the strip portion 36 toward the drive IC 6 . The connecting portion 39 has one end connected to the belt-like portion 36 and the other end connected to the bonding portion 37 . The bonding portion 37 is formed at the y-direction end portion of the individual electrode 35 and connected to the connecting portion 39 . Each bonding portion 37 is connected to one of the output pads 68 of the driver IC 6 via a bonding wire 73 . A portion of the connecting portion 39 and the bonding portion 37 are arranged on the die bonding glaze 192 .

The resistor layer 4 according to the present embodiment is made of, for example, ruthenium oxide, which has a higher resistivity than the material forming the conductive layer 3, and extends in the x direction on the heater glaze 191 of the first substrate main surface 11. It is shaped like a strip. The resistor layer 4 is formed by printing a thick film of a paste such as ruthenium oxide and then firing it. Although the thickness of resistor layer 4 is not particularly limited, it is, for example, about 3 to 10 μm. A plurality of resistor layers 4 are formed on the upper side of the plurality of band-shaped portions 32 of the common electrode 31 and the plurality of band-shaped portions 36 of the plurality of individual electrodes 35 (the side opposite to the first substrate 1) at a position near the center of the heater glaze 191. It is formed so as to intersect the band-shaped portion 32 and the plurality of band-shaped portions 36, respectively. A portion of the resistor layer 4 sandwiched between the strip portions 32 and the strip portions 36 serves as a heat generating portion 41 . The heat generating portion 41 is a portion that generates heat by being partially energized by the conductive layer 3, and this heat generation forms a print dot.

Protective layer 2 is formed to overlap first substrate main surface 11 of first substrate 1 and covers conductive layer 3 and resistor layer 4 . The protective layer 2 is made of an insulating material and protects the conductive layer 3 and the resistor layer 4 . Protective layer 2 is made of a glass material such as amorphous glass. The protective layer 2 is formed by printing a thick film of glass paste and then firing it. Although the thickness of protective layer 2 is not particularly limited, it is, for example, about 6 to 8 μm. The material of the protective layer 2 is not limited to amorphous glass, and any insulating material may be used.

Also in this embodiment, the same effects as in the first embodiment can be obtained.

The structure of the thermal printhead using the driver IC 6 according to the present disclosure is not limited. The driver IC 6 according to the present disclosure can be used regardless of the structure of the heat generating portion 41 of the thermal print head, the arrangement and shape of the conductive layer 3, and the mounting position and mounting method.

The driver IC for the thermal printhead and the thermal printhead according to the present disclosure are not limited to the embodiments described above. The driver IC for the thermal print head according to the present disclosure and the specific configuration of each part of the thermal print head can be designed and changed in various ways.

[Appendix 1]
A driver IC for a thermal print head that selectively drives a plurality of heat generating units arranged in parallel according to input print data,
a storage unit for storing current print data to be printed this time and next print data to be printed next time;
a switch for switching between an energized state in which current is passed through the heat generating portion and a cutoff state in which current is not passed to the heat generating portion, based on a strobe signal for controlling the energization time of the heat generating portion and the current print data;
a preheating signal generation unit that generates a preheating signal that shortens the energization time from the strobe signal;
a preheating unit that switches the switch based on the preheating signal when the current print data is "0" and the next print data is "1";
driver IC.
[Appendix 2]
The preheating signal generation unit
a filter circuit for transforming the strobe signal into a transformed signal;
an AND circuit for generating a logical product signal of the strobe signal and the modified signal as the preheating signal;
comprising
The driver IC according to appendix 1.
[Appendix 3]
the filter circuit comprises a first order series RC circuit;
3. A driver IC according to claim 2.
[Appendix 4]
the strobe signal and the preheat signal are pulse signals;
4. The driver IC according to any one of Appendices 1 to 3.
[Appendix 5]
The pulse width of the preheating signal is 30% or more and 80% or less of the pulse width of the strobe signal.
The driver IC according to appendix 4.
[Appendix 6]
The pulse width of the preheat signal is 45% or more and 55% or less of the pulse width of the strobe signal.
The driver IC according to appendix 4.
[Appendix 7]
the fall or rise timing of the preheat signal matches the fall or rise timing of the strobe signal;
7. A driver IC according to any one of Appendices 4 to 6.
[Appendix 8]
The preheat signal is a signal generated based on the strobe signal,
8. The driver IC according to any one of Appendices 1 to 7.
[Appendix 9]
The storage unit further stores previous print data that was the target of previous printing,
Further, the preheating unit switches the switch based on the preheating signal only when the previous print data is "0".
9. The driver IC according to any one of Appendices 1 to 8.
[Appendix 10]
The storage unit further stores the print data of the previous print that is the target of the print of the print of the print of the print of the previous print.
Further, the preheating unit switches the switch based on the preheating signal only when the print data of the second last print is "0".
The driver IC according to appendix 9.
[Appendix 11]
Further comprising a second preheating signal generation unit that uses the strobe signal to generate a second preheating signal that shortens the energization time from the preheating signal,
9. The driver IC according to any one of Appendices 1 to 8.
[Appendix 12]
Further comprising a second preheating signal generation unit that uses the preheating signal to generate a second preheating signal that shortens the energization time from the preheating signal,
9. The driver IC according to any one of Appendices 1 to 8.
[Appendix 13]
The storage unit further stores previous print data that was the target of previous printing,
The preheating section is
switching the switch based on the preheat signal when the previous print data is "0";
switching the switch based on the second preheating signal instead of the preheating signal when the previous print data is "1";
13. The driver IC according to appendix 11 or 12.
[Appendix 14]
a first substrate;
a resistor layer supported by the first substrate;
a conductive layer supported by the first substrate and for conducting electricity to the resistor layer;
a driver IC according to any one of Appendices 1 to 12;
a thermal printhead.

A1, A5: Thermal print head 1: First substrate 11: Main surface of first substrate 12: Rear surface of first substrate 13: Protruding portion 18: Insulating layer 19: Glaze layer 191: Heater glaze 192: Die bonding glaze 193: Intermediate glass Layer 194 : Edge glass layer 2 : Protective layer 21 : Opening 3 : Conductive layer 31 : Common electrode 311 : Branch portion 312 : Straight portion 32 : Strip portion 33 : Connection portion 34 : Detour portion 35 : Individual electrode 36 : Strip portion 37 : Bonding portion 39 : Connecting portion 38 : Relay electrode 381 : Strip portion 382 : Connecting portion 4 : Resistor layer 41 : Heat generating portion 5 : Second substrate 51 : Second substrate main surface 52 : Second substrate rear surface 55 : Control Electrodes 59: Connectors 6, 602, 603, 604: Driver IC
6a: Driver main surface 6b: Driver back surface 610: Shift register 61: Flip-flop 620: Latch registers 62, 63, 66: Latch circuit 65: Drive control unit 651: Preheating signal generation unit 652: Filter circuit 653: AND circuit 654: preheating section 655: AND circuit 656: OR circuit 657: second preheating signal generating section 64: switch 67: input pad 68: output pad 71: protective resin 73: bonding wire 8: heat dissipation member 81: first support surface 82: second 2 support surface 91: platen roller

Claims (13)

A driver IC for a thermal print head that selectively drives a plurality of heat generating units arranged in parallel according to input print data,
a storage unit for storing current print data to be printed this time and next print data to be printed next time;
a switch for switching between an energized state in which a current is passed through the heat generating portion and a cutoff state in which the current is not passed, based on a strobe signal, which is a signal for controlling the energization time of the heat generating portion, and the current printing data;
a preheating signal generation unit that generates a preheating signal that shortens the energization time from the strobe signal;
a preheating unit that switches the switch based on the preheating signal when the current print data is "0" and the next print data is "1";
with
The preheating signal generation unit
a filter circuit for transforming the strobe signal into a transformed signal;
an AND circuit for generating a logical product signal of the strobe signal and the modified signal as the preheating signal;
comprising
driver IC. the filter circuit comprises a first order series RC circuit;
A driver IC according to claim 1 . The storage unit further stores previous print data that was the target of previous printing,
Further, the preheating unit switches the switch based on the preheating signal only when the previous print data is "0".
3. The driver IC according to claim 1 or 2 . The storage unit further stores the print data of the previous print that is the target of the print of the print of the print of the print of the previous print.
Further, the preheating unit switches the switch based on the preheating signal only when the print data before last is "0".
4. The driver IC according to claim 3 . A driver IC for a thermal print head that selectively drives a plurality of heat generating units arranged in parallel according to input print data,
a storage unit for storing current print data to be printed this time and next print data to be printed next time;
a switch for switching between an energized state in which a current is passed through the heat generating portion and a cutoff state in which the current is not passed, based on a strobe signal, which is a signal for controlling the energization time of the heat generating portion, and the current printing data;
a preheating signal generation unit that generates a preheating signal that shortens the energization time from the strobe signal;
a preheating unit that switches the switch based on the preheating signal when the current print data is "0" and the next print data is "1";
a second preheating signal generator that uses the strobe signal to generate a second preheating signal that shortens the energization time from the preheating signal;
driver IC. A driver IC for a thermal print head that selectively drives a plurality of heat generating units arranged in parallel according to input print data,
a storage unit for storing current print data to be printed this time and next print data to be printed next time;
a switch for switching between an energized state in which a current is passed through the heat generating portion and a cutoff state in which the current is not passed, based on a strobe signal, which is a signal for controlling the energization time of the heat generating portion, and the current printing data;
a preheating signal generation unit that generates a preheating signal that shortens the energization time from the strobe signal;
a preheating unit that switches the switch based on the preheating signal when the current print data is "0" and the next print data is "1";
a second preheating signal generator that uses the preheating signal to generate a second preheating signal that shortens the energization time from the preheating signal;
driver IC. The storage unit further stores previous print data that was the target of previous printing,
The preheating section is
switching the switch based on the preheat signal when the previous print data is "0";
switching the switch based on the second preheating signal instead of the preheating signal when the previous print data is "1";
7. The driver IC according to claim 5 or 6 . the strobe signal and the preheat signal are pulse signals;
A driver IC according to any one of claims 1 to 7 . The pulse width of the preheating signal is 30% or more and 80% or less of the pulse width of the strobe signal.
A driver IC according to claim 8 . The pulse width of the preheat signal is 45% or more and 55% or less of the pulse width of the strobe signal.
A driver IC according to claim 8 . the fall or rise timing of the preheat signal matches the fall or rise timing of the strobe signal;
A driver IC according to any one of claims 8 to 10 . The preheat signal is a signal generated based on the strobe signal,
A driver IC according to any one of claims 1 to 11 . a first substrate;
a resistor layer supported by the first substrate;
a conductive layer supported by the first substrate and for conducting electricity to the resistor layer;
a driver IC according to any one of claims 1 to 12;
a thermal printhead.

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