JPS5926279A - Thermal head - Google Patents

Abstract

PURPOSE:To unnecessitate complicated circuits such as a distributing circuit, by a method wherein driving circuits on both sides are connected in series with each other, and data are inputted through a single data input terminal, in a distributing-type thermal head. CONSTITUTION:Heating resistors 1 are so constructed that odd-numbered driving circuits C1-Cn-1 are placed on the upper side, while even-numbered driving circuits C2-Cn are placed on the lower side, and the circuits are connected in series with each other. When data are transferred serially through an input data wire 2 in the order of 1 n, the data are inputted first into the n-th driving circuit Cn, is then sequentially transferred into Cn-1, then into Cn-2 and so on, and when the first data reach the first driving circuit C1, each of the driving circuits C1-Cn is operated to drive the heating resistor 1, thereby developing a color at a corresponding part of a heat-sensitive recording paper. Accordingly, complicated circuits are unnecessitated, and the number of production steps can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used in printers, facsimile machines, etc., and converts information sent as electrical signals into letters and letters on thermal recording paper.
The present invention relates to thermal heads for converting symbols or images, and in particular to so-called distributed type thermal heads in which drive circuits are arranged on both sides of an array of heating resistors.

In a thermal head in which heat generating resistors are arranged in high density, it is not possible to place all of the drive circuits on one side of the heat generating resistor array, so the drive circuits are distributed and arranged on both sides of the heat generating resistor array. There is.

In the conventional thermal head of this kind of distribution type, as shown in Fig. 1, r C (integrated circuit such as 551, MSI, LSI) is placed on both sides along the array 1 of heating resistors.
Drive circuits such as C
The next predetermined number of heat generating resistors are connected to the lower drive circuit C2, and the next predetermined number of heat generating resistors are connected to the lower drive circuit C2.
The configuration is such that the input data is sequentially and alternately input to the upper drive circuit and the lower drive circuit, such that the input data is connected to the drive circuit C3 on the second side. On the other hand, since the input data is serially transferred through the input data line 2, a toggle switch or the like is used to distribute the input data into a channel for the upper drive circuit group and a channel for the upper drive circuit group. requires circuit 3.

Therefore, the conventional distribution type thermal head has a problem of being complicated and expensive.

In view of the above-mentioned problems, the present invention aims to provide a simple distribution type thermal head, in which data input from one data input terminal is transmitted to an array of heating resistors. By connecting the drive circuits on both sides to each other so that the data is transferred sequentially and alternately, the allocation circuit is unnecessary, thereby achieving the above object.

In the present invention, for example, as shown in FIG. 2, odd-numbered drive circuits C□ are placed above the array 1 of heating resistors.

C3, . . . C, -□ are arranged, and even numbered drive circuits C2, C4, . The transferred data first enters the lower n-th drive circuit Cn,
It passes through the drive circuit C1 and enters the upper drive circuit Cn-□, and then passes through the drive circuit C1-1 and then enters the lower drive circuit again. In this way, the upper and lower drive circuits are connected. The data is transferred alternately, and when the first data reaches the first drive circuit C0, the drive circuits C1 to C11 are operated so as to drive the heating resistor 1.

An example will be described below.

Figure 3 shows the type of distribution using the direct drive method.
That is, an embodiment will be shown in which the present invention is applied to a line buffer thermal head in which ICs are arranged on both sides of a heat generating resistor array.

Heating resistor array 1 consists of 1024 heating resistors (R1-") along the longitudinal direction (horizontal direction in the figure) of the thermal head.
1024) and is divided into 32 groups each containing 32 heating resistors.

The drive circuit includes 32 tCs, each IC (each part surrounded by a chain line represents an ICI chip) has 32 output terminals connected to the electrodes of the heating resistor, and the odd-numbered IC At the bottom of the diagram, even-numbered ICs are arranged at the top of the diagram, and the first lower Ic1 connects the first group of heating resistors (32 to R□~), and the second upper IC2 The second group of heating resistors (k33 to 64),
In this way, each group of 32 heating resistors is configured to be driven by one IC. One side of the electrodes of the heating resistors R1 to R1024 is connected to the IC, and the other side is connected to the electrode terminal HD as a common electrode.

Each IC includes a shift register 10 that inputs and transfers data at the timing of a clock signal from a clock terminal GK, and a latch circuit 11 that inputs and temporarily holds data from the shift register 10 in response to a load signal from a load terminal LD.
and the heating resistor 1 based on the data held in the latch circuit 11.
A transistor 12 that drives
strobe terminals SB1 to SBg
AND gate 13 controlled by a strobe signal from
It is equipped with The base of the transistor 12 is the gate 1
3, the collector is connected to the heating resistor and the electrodes of □ to R1o24, and the emitter is connected to the ground terminal GND. The shift register 11 is connected to the 32nd IC on the upper side.
The input terminal of the shift register 10 of 32 is connected to the connector CN3.
The output terminal of the shift register 10 is connected to the input terminal of the shift register 10 of the 31st I Ca□ on the lower side, and the output terminal -r of the shift register 10 of that ■C3□ - is then connected to the input terminal of the shift register 10 of the 30th lC3o on the upper side, and in this way, the connection is made such that data is transferred alternately and sequentially between the upper and lower tC shift registers. has been done. Such a connection between the shift registers 11 can be made, for example, by drawing out the input terminals and output terminals of the shift registers, forming pads, and soldering jumper wires. In addition, in FIG. 3, terminal CR is the clear terminal of the shift register 10 (vDI)
and vss are a driving power supply terminal and a ground terminal of the logic circuit itself at tC, respectively. and the strobe end)
The reason why the heating resistor array 1 is divided into eight groups n1 to 18 is to allow the heating resistor array 1 to be divided into eight groups and to freely perform simultaneous or divided driving depending on the recording speed.

In this embodiment, from the input data line to the data input terminal D
When data is serially input to I, the data is input to IC-
+IC+Ic →・・・・・・→I C232313
0→IC1 and is sequentially transferred through the shift register 10. When the data is transferred to the shift register 1° of the IC 1, a load signal is sent from the load terminal LD to the latch circuit 11, and the data in the shift register 10 is transferred to the latch circuit 11. After that, when a strobe signal is sent to the gate 13 from the strobe terminals SB1 to SB8 at an appropriate timing, the gate 13 opens and a predetermined transistor 12 is turned on according to the data held in the latch circuit 11, and the Passing through the heating resistor 1 connected to the transistor 12,
A current flows from the transistor 12 to the ground terminal GND. Thus, the heating resistor 1 generates heat, and the corresponding portion of the thermal recording paper develops color.

As described above, in the present invention, the drive circuits on both sides of the heat generating resistor array are connected to each other so that data is sequentially and alternately transferred, so that the input data line is not transferred serially. It is sufficient to simply input the data as is to the data input terminal, and distribution does not require a complicated circuit. Therefore, a thermal head can be achieved at low cost and with fewer manufacturing steps.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a data transfer method in a conventional distribution type thermal head, Fig. 2 is a schematic diagram showing a data transfer method according to the present invention, and Fig. 3 is a circuit diagram showing an embodiment of the present invention. It is a diagram. 1... Heating resistor array, 2... Input data line, 3...
... Shake, minute is circuit, 10... multi-ft register, 00~
co...drive circuit, IC, IC...IC, DI...
・Data input 1 32 terminal. Patent applicant Ricoh Co., Ltd.

Claims (1)

[Claims] (1) In a distribution type thermal head in which drive circuits are arranged on both sides of the array of heating resistors, the drive circuits on both sides are connected in series and data is input from one data input terminal. A thermal head characterized by: