CN201240107Y

CN201240107Y - Control circuit for pin of stylus printer

Info

Publication number: CN201240107Y
Application number: CNU2008200489840U
Authority: CN
Inventors: 莫达庭
Original assignee: Shenzhen Deka Technology Co Ltd
Current assignee: Shenzhen Deka Technology Co Ltd
Priority date: 2008-06-05
Filing date: 2008-06-05
Publication date: 2009-05-20
Anticipated expiration: 2018-06-05

Abstract

The utility model discloses a print needle control circuit of a stylus printer, which comprises a signal control module, a print needle drive circuit, a reverse voltage clamp circuit, and a print head winding; the withdrawing needle control signal output end of the signal control module is connected with a print needle drive circuit; one output end of the print needle drive circuit is connected with the print head winding, and the other end of the print head winding is connected with the print needle drive electric supply; the reverse voltage clamp circuit comprises a electric discharge triode and a switch module controlling the electric discharge triode switch; another output end of the print needle drive circuit is connected with the electric discharge triode; the signal control module is provided with an electric discharge switch control signal output end connected with the electric discharge triode by a switch module; and the collector of the electric discharge triode is connected with the print needle drive electric supply. The electric discharge circuit substitutes the triode for the previous diode, the electric discharge speed is lower, the shorter time is required to maintain the voltaic stable during compensate control, and the power consumption can be reduced.

Description

The print needle control circuit of impact printer

Technical field

The utility model relates to a kind of circuit of impact printer, particularly a kind of print needle control circuit.

Background technology

In the print needle control circuit of high speed impact printer, need to adopt the backward voltage clamp circuit, the electric current of control print needle coil when going out pin, the narrowing time shortening with print needle goes out the pin frequency thereby improve printhead, realizes flying print.

Referring to Fig. 1, Fig. 2, adopt the printer control circuit cardinal principle of backward voltage clamp circuit to be at present:

1, go out stylus printer when seal when print needle receives print data, control chip H opens print needle drive circuit U1, and power supply is to printhead coil L charging, and printhead coil L electric current increases.

2, when the printhead cluster loop current reaches the pin upper current limit, control chip H disconnects print needle drive circuit U1, printhead coil L discharge, and the recoil electromotive force raises, as A point voltage (V _A) be higher than supply voltage (V _P) with the reverse-conducting voltage (VZ of diode ZD1 _D1) the voltage sum time, i.e. V _AV _P+ V _ZD1, diode ZD1 conducting, printhead coil electric energy discharges by diode ZD1, and the printhead cluster loop current reduces.

3, when the printhead cluster loop current drops to lower current limit, control chip H opens print needle drive circuit U1 again, printhead coil L charging, and this moment, the A point voltage descended, and diode ZD1 ends, and the printhead cluster loop current increases.

4, when the printhead cluster loop current reaches the pin upper current limit, control chip disconnects print needle drive circuit U1, and repeating step 2 remains in certain scope with the current value of step 3 control printhead, goes out pin until printhead and finishes.

In above-mentioned circuit, its backward voltage clamp circuit is to utilize diode to carry out current limliting.The velocity of discharge of this circuit is fast, and the rate of decay of electric current is very fast, needs the long charging interval to keep the stable of electric current when compensation control, increases power consumption, is unfavorable for the overall power control of printer.

Summary of the invention

At the problem that prior art exists, the purpose of this utility model is to provide a kind of print needle control circuit that can effectively reduce the impact printer of power consumption.

The technical scheme in the invention for solving the technical problem is:

The print needle control circuit of impact printer, comprise the signal controlling module, the print needle drive circuit, backward voltage clamp circuit and printhead coil, the pin control signal output that goes out of signal controlling module is connected with the print needle drive circuit, one output of print needle drive circuit is connected with the printhead coil, another termination print needle driving power of printhead coil, described backward voltage clamp circuit comprises the switch module of a discharge triode and this discharge triode switch of control, another output of print needle drive circuit is connected with the discharge triode, the signal controlling module has discharge switch control signal output to be connected with the discharge triode by switch module, and the colelctor electrode of discharge triode is connected with the print needle driving power.

The beneficial effects of the utility model are: because the discharge circuit of the backward voltage clamp circuit in control circuit is a triode, the base current of triode and the relation of emitter current can determine the speed of discharging, its velocity of discharge can be allocated according to the triode specification, may be controlled to the slower velocity of discharge, the rate of decay of electric current is slower, when compensation control, need the short charging interval can keep the stable of electric current, obviously reduce power consumption, help the printer product and realize the low-power consumption high-performance.

Description of drawings

Below in conjunction with accompanying drawing the utility model is described further.

Fig. 1 is the print needle control circuit schematic diagram of prior art;

Fig. 2 is the control situation of print needle coil current of the print needle control circuit of prior art.

Fig. 3 is a print needle control circuit schematic diagram of the present utility model;

Fig. 4 is the control situation of the print needle coil current of the utility model print needle control circuit;

Fig. 5 is drive waveforms figure of the present utility model.

The specific embodiment

With reference to Fig. 3, the print needle control circuit of impact printer of the present utility model, comprise signal controlling module FPGA, print needle drive circuit U1, backward voltage clamp circuit U2 and printhead coil L, the pin control signal output that goes out of signal controlling module FPGA is connected with print needle drive circuit U1, the output of print needle drive circuit U1 is connected with printhead coil L, another termination print needle driving power VP of printhead coil L, described backward voltage clamp circuit U2 comprises the switch module U20 of a discharge triode PQ1 and this discharge triode of control PQ1 switch, another output of print needle drive circuit U1 is connected with discharge triode PQ1, signal controlling module FPGA has discharge switch control signal output to be connected with discharge triode PQ1 by switch module U20, and the colelctor electrode of discharge triode PQ1 is connected with print needle driving power VP.

Further, described switch module U20 comprises resistance R 2 and triode NQ1, one end of resistance R 2 connects the base stage of discharge triode PQ1, the other end connects the colelctor electrode of triode NQ1, the grounded emitter of triode NQ1, base stage are connected to the discharge switch control signal output of signal controlling module FPGA.

In addition, further, described switch module U20 also comprises Zener diode ZD1 and diode D1, and Zener diode ZD1 is connected between the colelctor electrode and base stage of discharge triode PQ1, and diode D1 is connected between the colelctor electrode of resistance R 2 and triode NQ1.

As preferred implementation, described discharge triode PQ1 is the positive-negative-positive triode, and its emitter stage is connected with print needle drive circuit U1, and base stage is connected with switch module U20, and colelctor electrode connects print needle driving power VP.

Operation principle of the present utility model: drive triode from signal controlling module FPGA output print eedle control signal to printhead, drive waveforms as shown in Figure 5.When the time arrives T1, signal controlling module FPGA output discharge control signal SGCNT, discharge control signal SGCNT opens triode NQ1, thus conducting discharge triode PQ1, when the time arrives T2, close corresponding print needle drive circuit U1, the recoil electromotive force of printhead coil L carries out the release of electric energy by the discharge triode PQ1 of correspondence, opens print needle drive circuit U1 during T3 again, charges to printing head coil L, repeat said process, up to finishing out the pin process.

Wherein, print needle goes out pin control signal HP, is issued to print needle drive circuit U1 from signal controlling module FPGA, control print needle drive circuit U1 switch, thus control out pin.Go out needle-discharging switch controlling signal SGCNT, FPGA is issued to switch module U20 from the signal controlling module, gauge tap module U20 triode NQ1 switch wherein, thereby the switch of control discharge triode PQ1.The recoil electromotive force Cop of printhead coil is by driving chip to the discharge triode.

Export out needle-discharging switch controlling signal SGCNT from signal controlling module FPGA and open triode NQ1; Zener diode ZD1; diode D1 conducting; thereby conducting discharge triode PQ1; when being transmitted to from driving chip, the recoil electromotive force Cop of printhead coil is discharged into print needle driving power Vp by discharge triode PQ1; discharge triode PQ1 base stage has electric current can regulate by resistance R 2 with the velocity of discharge of passing through; effect is when Zener diode ZD1 or discharge triode PQ1 damage; diode D1 shields, and wherein Zener diode ZD1 can shield when discharge triode PQ1 damages.Discharge triode PQ1 can be bigger with amplification coefficient, and withstand voltage higher, triodes such as NPN that peak point current is bigger or PNP multiple tube replace, and triode NQ1 is also available to be replaced by the bigger triode of electric current.Because its base current and values of factor K can determine the speed of discharging, the Current Control situation of print needle coil when going out pin is referring to Fig. 4.Therefore can select the triode of appropriate specification, be controlled to be the slower velocity of discharge, current attenuation is slow, and its compensation also just needs the short period, thereby reduces the power consumption of printer.According to the reality test, can reduce the about 20-50% of printhead power, help the printer product and realize the development of low-power consumption high-performance.

Claims

1. the print needle control circuit of impact printer, comprise signal controlling module (FPGA), print needle drive circuit (U1), backward voltage clamp circuit (U2) and printhead coil (L), the pin control signal output that goes out of signal controlling module (FPGA) is connected with print needle drive circuit (U1), one output of print needle drive circuit (U1) is connected with printhead coil (L), another termination print needle driving power (VP) of printhead coil (L), it is characterized in that: described backward voltage clamp circuit (U2) comprises the switch module (U20) of a discharge triode (PQ1) and this discharge triode (PQ1) switch of control, another output of print needle drive circuit (U1) is connected with discharge triode (PQ1), signal controlling module (FPGA) has discharge switch control signal output to be connected with discharge triode (PQ1) by switch module (U20), and the colelctor electrode of discharge triode (PQ1) is connected with print needle driving power (VP).

2. the print needle control circuit of impact printer according to claim 1, it is characterized in that: described switch module (U20) comprises resistance (R2) and triode (NQ1), one end of resistance (R2) connects the base stage of discharge triode (PQ1), the other end connects the colelctor electrode of triode (NQ1), the grounded emitter of triode (NQ1), base stage are connected to the discharge switch control signal output of signal controlling module (FPGA).

3. the print needle control circuit of impact printer according to claim 2, it is characterized in that: switch module (U20) also comprises Zener diode (ZD1) and diode (D1), Zener diode (ZD1) is connected between the colelctor electrode and base stage of discharge triode (PQ1), and diode (D1) is connected between the colelctor electrode of resistance (R2) and triode (NQ1).

4. according to the print needle control circuit of claim 1,2 or 3 described impact printers, it is characterized in that: described discharge triode (PQ1) is the positive-negative-positive triode, its emitter stage is connected with print needle drive circuit (U1), base stage is connected with switch module (U20), and colelctor electrode connects print needle driving power (VP).