JP3295492B2 - Structure of line type thermal print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal print head used for a facsimile or a printer, the print width of which is increased to match the width of a relatively wide sheet such as A row 4th. The structure of a thermal print head.

[0002]

2. Description of the Related Art Conventionally, a line type thermal print head of this kind, for example, described in Japanese Patent Application Laid-Open No. 2-103157, and as shown in FIGS. A print line C in which a number of unit resistor dots are arranged in a line is formed on the upper surface of the head substrate B adhered to the head substrate B so as to extend in parallel with one longitudinal side surface B1 of the head substrate B. A wide common lead D is formed so as to extend in parallel with the print line C along one longitudinal side surface B1 of the head substrate B. Further, each unit in the print line C is formed on the upper surface of the head substrate B. Resistor dots and a plurality of driving semiconductor chips E mounted in a line on the upper surface of the head substrate B
And a plurality of individual leads F for connecting each unit resistor dot and the common lead D in the print line C.
And a plurality of common electrodes G for connecting
Each of the individual leads F and each of the output terminals of each of the driving semiconductor chips E are electrically connected by wire bonding with a metal wire H or the like.

Further, a control signal metal line L is provided between each input terminal of each drive semiconductor chip E and various control signal wiring patterns K1 on the upper surface of the circuit board J fixed to the heat sink A. Electrical connection by wire bonding or the like, and wire bonding between the both ends D1 and D2 of the common lead D and the common wiring pattern K2 on the upper surface of the circuit board J by a metal wire M for common. Is configured to be electrically connected.

[0004]

However, the conventional line type thermal print head has the following problems. That is, in this line type thermal print head, the voltage drop along the longitudinal direction of the common lead D becomes large because the length of the common lead D becomes considerably long.

Therefore, conventionally, the width W 'of the wide common lead D is further increased or the common lead D is formed in a two-layer or three-layer structure to reduce the voltage drop in the longitudinal direction. Although the width is reduced, the wide common lead D is provided between the print line C and the longitudinal one side surface B1 of the head substrate B, so that the longitudinal one side surface B of the head substrate B is provided.
1 and the print line C must be increased by an amount corresponding to the provision of the wide common lead D at a portion between them, so that the print line C B1 is far away from B1, so that the printing characteristics of the printing line C are considerably deteriorated.
Since the first and the first D2 are disposed outside the both ends of the print line C, the length of the head substrate B is increased by both ends D1 and D2 of the common lead D. .

It is a technical object of the present invention to solve these problems and to increase the number of driving semiconductor chips mounted on a head substrate to increase the printing density.

[0007]

According to the present invention, a head substrate and a circuit board are arranged and fixed on an upper surface of a heat radiating plate, and a plurality of units are mounted on the upper surface of the head substrate. A print line in which resistor dots are arranged in a line is formed so as to extend in parallel along one longitudinal side surface of the head substrate, and each of the plurality of unit resistor dots and each of the plurality of drive semiconductor chips has an output. In a line type thermal print head formed by forming a large number of individual leads for electrically connecting terminals, a portion of the upper surface of the head substrate between the print line and the circuit board, A common lead that is electrically connected to the unit resistor dot via many common-side electrodes,
The common lead is formed so as to extend substantially parallel to the print line, and the plurality of semiconductor chips are arranged on the upper surface of the common lead via an insulating layer in a state where the semiconductor chips are arranged in a line. While mounting , the circuit board
Each part corresponding to each of the semiconductor chips on the upper surface
In addition, multiple control signal wiring patterns and common wiring patterns
Turn and common wiring pattern for each control signal wiring
The semiconductor chips are formed so as to be located between the patterns.
Input terminals and the control of each semiconductor chip.
Control metal wiring with control signal wiring pattern
The common lead and each of the semiconductors.
The common wiring pattern for each chip is
A chip disposed between the control signal metal wires for each chip.
Electrically connected with a metal cable for MON. " .

[0008]

[Operation] As described above, the common lead electrically connected to each unit resistor dot via a large number of common-side electrodes at a portion of the upper surface of the head substrate between the print line and the circuit substrate. Is formed so that the common lead extends substantially parallel to the print line, and a plurality of semiconductor chips are mounted on the upper surface of the common lead via an insulating layer.
The lower part of each semiconductor chip can be used for forming a common lead, and the formation of the common lead between one longitudinal side surface of the head substrate and the print line as in the related art is omitted. Therefore, the printing line can be brought closer to one longitudinal side surface of the head substrate, and the width of the common lead can be greatly increased. Voltage drop can be significantly reduced, and by connecting a common lead to each unit resistor dot via a number of common side electrodes, it is possible to achieve a uniform voltage for each unit resistor dot. is there.

Further, each half of the upper surface of the circuit board is provided.
At each of the locations corresponding to the conductor chips,
Connect multiple turns and common wiring pattern to common
Position the wiring pattern between each control signal wiring pattern.
And each input terminal of each semiconductor chip.
Wiring pattern for each control signal for each chip and the semiconductor chip
Is electrically connected with a control signal metal wire.
For the common for the common lead and each semiconductor chip
The wiring pattern is defined by each of the semiconductor chips.
Electricity is supplied by the common metal wire arranged between the control signal metal wires.
Since the connection between the semiconductor chips can be made much narrower than the case where the common metal wire is provided at a position between the semiconductor chips, the printing line can be greatly reduced. The number of semiconductor chips that can be provided in a line along the line can be increased, and the density can be increased. In addition, the variation in voltage between the semiconductor chips can be reduced by the common metal. since it can also be greatly reduced by the case of disposing a line portion between mutually in each semiconductor chip, it can improve the printing performance.

[0010]

As described above, according to the present invention, the printing characteristics of the line type thermal print head can be reduced in such a manner that a voltage drop occurs in the common lead and that the voltage applied to each unit resistor dot can be made uniform. As well as being able to improve reliably, it is possible to improve the printing density by increasing the number of driving semiconductor chips, and has an effect.Moreover, outside the both ends of the printing line, as in the conventional case,
There is no need to dispose both ends of the common lead, and the length can be shortened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In this figure, reference numeral 1 denotes a heat radiating plate made of metal such as aluminum, on which a head substrate 2 made of ceramic and a circuit board 3 with connection sockets 3a are provided.
Each of them is fixed with an adhesive or the like in a state of being arranged substantially in parallel.

A print line 4 in which a number of unit resistor dots 4a are arranged in a line is formed on a portion of the upper surface of the head substrate 2 adjacent to one longitudinal side surface 2a opposite to the circuit substrate 3. A wide common lead 5 is formed at a portion of the upper surface of the head substrate 2 near the other longitudinal side 2b on the circuit board 3 side, and the printing line is formed so as to extend in parallel along one longitudinal side surface 2a of the head substrate 2. 4 is formed so as to extend in parallel with the common lead 5.
Is formed so that a portion of the common lead 5 from the other side surface 2a is exposed, and on the upper surface of the insulating layer 6,
A plurality of driving semiconductor chips 7 are mounted such that each of the semiconductor chips 7 arranges the print lines 4 in a row substantially in parallel.

Further, a portion of the upper surface of the head substrate 2 between the print line 4 and the common lead 5 is connected to one end of each of the unit resistor dots 4a on the print line 4 by the semiconductor chip 7 And a plurality of common-side electrodes for electrically connecting the other end of each unit resistor dot 4a in the print line 4 to the common lead 5. 9 is formed.

The individual leads 8 are electrically connected to the respective output terminals 7a of the respective semiconductor chips 7 by wire bonding using individual metal wires 10. On the other hand, each semiconductor chip on the upper surface of the circuit board 3
Wiring patterns for control signals
And the common wiring pattern 13
Wiring pattern 13 for each control signal.
Between the semiconductor chips 7.
Input terminals 7b of the semiconductor chip,
Each control signal wiring pattern 11 is electrically connected to the control signal metal wire 12 by wire bonding.

Further, the common lead 5 and each of the semiconductors 5
Between each common wiring pattern 13 for each body chip 7
The metal for each control signal for each of the semiconductor chips 7
Oite the site between the line 12 is to electrically connect a wire bonding with the common metal lines 14.

The semiconductor chip 7 and the metal wires 10, 12, 14 are packaged with a synthetic resin 15. As described above, a common portion electrically connected to each unit resistor dot 4 a via a large number of common side electrodes 9 at a portion between the print line 4 and the circuit board 3 on the upper surface of the head substrate 2. By forming the lead 5 so that the common lead 5 extends substantially in parallel with the printing line 4, and mounting a plurality of semiconductor chips 7 on the upper surface of the common lead 5 via the insulating layer 6, The lower portion of each semiconductor chip 7 on the upper surface of the head substrate 2 can be used for forming the common lead 5, and as in the conventional case shown in FIGS. Since the formation of the common lead D between the longitudinal one side surface B1 and the print line C can be omitted, the print line 4 is brought closer to the longitudinal one side surface 2a of the head substrate 2 and the dimension T between them is reduced. It is possible to significantly narrow.

Moreover, the width W of the common lead 5 can be greatly increased as shown in the figure, so that the voltage drop along the longitudinal direction of the common lead 5 can be significantly reduced. By connecting the common lead 5 to each unit resistor dot 4a through a large number of common-side electrodes 9, the voltage uniformity for each unit resistor dot 4a can be achieved.

Each of the upper surfaces of the circuit board 3
Control signal distribution is provided at each of the locations corresponding to the semiconductor chip 7.
A plurality of line patterns 11 and a common wiring pattern 13
And the common wiring pattern 13 to each control signal wiring pattern.
Formed between the respective semiconductor chains.
Input terminals 7b in the chip 7 and the semiconductor chip
Between the control signal wiring pattern 11 and
Electricity by wire bonding with signal metal wire 12
While the common lead 5 and each of the semiconductors 5
Between each common wiring pattern 13 for each body chip 7
The metal for each control signal for each of the semiconductor chips 7
In a portion between the wires 12, a common metal wire 14 is used.
Due to electrical connection by wire bonding
Ri, spacing dimension S between each other in each of the semiconductor chips 7
Can be made much narrower than in the case where the common metal wires 13 are arranged at positions between the semiconductor chips 7, so that the semiconductor chips 7 can be provided in a line along the print line 4. Can be increased, and the voltage variation between the semiconductor chips 7 can be greatly increased as compared with the case where the common metal wires 14 are arranged at positions between the semiconductor chips 7. since it is possible to reduce, it can improve the printing performance.

In addition, there is no need to dispose both ends D1 and D2 with respect to the common lead D outside the left and right ends of the print line 4 as in the conventional case shown in FIGS. The length of the head substrate 2 can be reduced, and the thermal print head can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is a plan view of a thermal printhead according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged plan view of a main part of the thermal print head according to the embodiment of the present invention.

FIG. 4 is an enlarged perspective view of a main part of the thermal print head according to the embodiment of the present invention.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a plan view of a conventional thermal print head.

FIG. 8 is an enlarged plan view of a main part of a conventional thermal print head.

9 is a sectional view taken along line IX-IX of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat sink 2 Head board 3 Circuit board 4 Print line 4a Unit resistance dot 5 Common lead 6 Insulating layer 7 Semiconductor chip 7a Output terminal of semiconductor chip 7b Input terminal of semiconductor chip 8 Individual lead 9 Common side electrode 10 Individual metal wire 11 Wiring pattern for control signal 12 Metal wire for control signal 13 Wiring pattern for common 14 Metal wire for common

Claims (1)

(57) [Claims] 1. A head substrate and a circuit board are arranged and fixed on an upper surface of a heat radiating plate, and a print line in which a number of unit resistor dots are arranged in a line is formed on the upper surface of the head substrate. and forming so as to extend in parallel along the side, forming a large number of individual leads for electrically connecting between the output terminal in the plurality each of the unit resistors dots and a plurality of driving semiconductor chips In a line type thermal print head comprising: a plurality of common side electrodes for each of the unit resistor dots, at a portion of the upper surface of the head substrate between the print line and the circuit board; The common leads are formed such that the common leads extend substantially parallel to the print line, and the plurality of semiconductor chips are mounted on the upper surface of the common leads. One for mounting through an insulating layer to the semiconductor chips in a state arranged in a row
On the other hand, the upper surface of the circuit board corresponds to the respective semiconductor chips.
In each of the corresponding locations, a plurality of control signal wiring patterns
And the common wiring pattern, and the common wiring pattern
Formed to be located between each control signal wiring pattern
And each input terminal of each semiconductor chip and the semiconductor
Control between each control chip wiring pattern for each body chip
Electrically connected with signal metal wires, and
And common wiring pattern for each semiconductor chip
And the control signal metal for each of the semiconductor chips.
Electrically connected by a common metal wire arranged between the wires
The structure of a line type thermal print head , characterized in that: