KR20060060442A - Ink jet printer head - Google Patents

Abstract

The present invention discloses a head of an inkjet printer. The head of the inkjet printer includes a logic unit for outputting a discharge enable signal in response to an input signal input from the outside, a substrate temperature sensor for sensing a temperature of a substrate, and a temperature of the substrate and the discharge in detected by the substrate temperature sensor And a driving unit for discharging ink through a nozzle when the temperature of the substrate is greater than or equal to a predetermined temperature in response to the enable signal, and heating the substrate when the temperature of the substrate is less than or equal to a predetermined temperature. Therefore, when the temperature of the head substrate is low, the substrate can be heated evenly, and the heating time also becomes short.

Description

Ink jet printer head

1 shows a circuit diagram of one group of a discharge heater driving circuit of a conventional inkjet printer head.

2 shows a layout of a conventional inkjet head substrate.

Fig. 3 shows a circuit diagram of one group of the discharge heater driving circuit of the inkjet printer head of the present invention.

4 is a diagram for explaining a wiring method of the discharge heater driving circuit of the inkjet printer head of the present invention.

Fig. 5 shows a discharge heater driving circuit of the ink jet printer head of the present invention.

Fig. 6 shows the layout of the ink jet printer head substrate of the present invention.

TECHNICAL FIELD The present invention relates to a head of an inkjet printer, and more particularly, to a head of an inkjet printer that heats a head substrate using a power transistor.

In the inkjet printer, the bubblejet method of discharging ink using a bubble (bubble) obtained by heating the ink is most widely used. The bubblejet inkjet printer head includes a plurality of nozzles and a discharge heater positioned below the nozzle, and when the ink is heated by operating the discharge heater to generate the bubble, the nozzle is pushed out by the generated bubble. It is configured to discharge the ink through.

By the way, in the case of such a bubblejet inkjet printer, the temperature of the substrate of the inkjet printer head has an important effect on the ejection performance of the ink.

That is, when the temperature of the substrate rises above a certain temperature (ie, about 60 ° C to 70 ° C), the viscosity of the ink decreases and other physical properties change, thereby increasing the size of the ejected ink droplets. It will lead to degradation. In the case of printing a high coverage pattern in which photographic images or other inks are formed, the temperature of the substrate increases because all the nozzles operate at the maximum frequency within the spec at the same time. Will occur.

 In addition, when the substrate temperature is equal to or lower than room temperature (that is, 20 ° C), even if the discharge heater is operated, discharge is not performed well until the substrate temperature increases by a predetermined temperature (about 30 ° C) or more. In general, when the indoor temperature is low in winter or when the printer is not used for a long time, the substrate temperature falls below room temperature. When the printer is operated in such a state, the initial printing state is deteriorated due to the above-described problems.

Therefore, it is very important to keep the substrate temperature at a constant level.

1 is a view for explaining the operation of the discharge heater of the head of a conventional inkjet printer, a plurality of discharge heater (R1, R2, ..., Rn) and a plurality of corresponding power transistors (FET1, FET2, ..., FETn) 1, V1 denotes a discharge heater driving voltage, S1, S2,... , Sn is a discharge enable signal.

Referring to Figure 1 describes the operation of the discharge heater of the head of a conventional inkjet printer as follows.

When the discharge enable signals S1, S2, ..., Sn are activated, the corresponding power transistors FET1, FET2, ..., FETn are turned on. Therefore, when the discharge heaters R1, R2, ..., Rn corresponding to the on-power transistors FET1, FET2, ..., FETn operate, and the discharge heaters R1, R2, ..., Rn operate, the above-described process The ink is discharged through the nozzle through the nozzle.

FIG. 2 is a diagram showing a layout of a head substrate of a conventional inkjet printer, comprising a logic circuit 1-1, 1-2, a substrate temperature sensor 2-1, 2-2, and a plurality of discharge heaters. It consists of the discharge heater area | region 3 comprised, the address decoders 4-1 and 4-2, the power transistor area | regions 5-1 and 5-2, and the board | substrate heaters 6-1 and 6-2. In FIG. 2, Pad denotes a pad that receives a signal input from the outside.

The function of each of the circuits and blocks shown in FIG. 2 will be described below.

Logic circuits 1-1 and 1-2 decode signals input from an external printer ASIC and transmit address signals through address signal lines arranged over address decoders 4-1 and 4-2. Output

The address decoders 4-1 and 4-2 decode the address signal and apply a discharge enable signal to each power transistor arranged in the power transistor regions 5-1 and 5-2.

In the power transistor regions 5-1 and 5-2, a plurality of power transistors FET1, FET2, ..., FETn shown in FIG. 1 are disposed, and the plurality of power transistors FET1, FET2, ..., FETn Each drive the corresponding discharge heater in response to the discharge enable signal. As shown in Fig. 2, in order to supply a sufficient amount of current to the discharge heaters in the discharge heater region 3, the power transistor regions 5-1 and 5-2 occupy most of the area of the print head substrate. .

The discharge heater area 3 includes a plurality of discharge heaters, and as described with reference to FIG. 1, operates by a power transistor turned on and off in response to the discharge enable signal, and ink may be discharged through a nozzle. Make sure

The substrate temperature sensors 2-1 and 2-2 sense the temperature of the substrate. Substrate temperature sensors 2-1 and 2-2 are constructed using a thermal resistance element whose resistance of the source changes as the temperature changes, or a diode is designed on the substrate, and the temperature is changed using the temperature change characteristic of the diode. It may be configured to detect.

The substrate heaters 6-1 and 6-2 function to heat the substrate when the temperature of the substrate is low in response to the temperature of the substrate detected by the substrate temperature sensors 2-1 and 2-2. .

By the way, in the case of the conventional inkjet printer head, as shown in Fig. 2, the substrate heaters 6-1, 6-2 are inevitably disposed on the outer surface of the substrate, such as one or both ends of the printer head substrate. . Therefore, even when the substrate heaters 6-1 and 6-2 operate to increase the temperature of the print head substrate, there is a disadvantage in that it is difficult to evenly heat the print head substrate.

In addition, there is a disadvantage in that the heating time is long because the heaters 1-1 and 6-2 disposed on the outer surface of the substrate must be heated up to the portion where the nozzle is located (that is, the discharge heater region 3).

SUMMARY OF THE INVENTION An object of the present invention is to provide a head of an ink jet printer that can heat a substrate evenly without using a separate substrate heater and can shorten the heating time.

The head of the inkjet printer of the present invention for achieving the above object is a logic unit for outputting a discharge enable signal in response to an input signal input from the outside, a substrate temperature sensor for sensing the temperature of the substrate, and the substrate temperature sensor In response to the temperature of one substrate and the discharge enable signal, the ink is discharged through a nozzle when the temperature of the substrate is higher than or equal to a predetermined temperature, and a driving unit is provided to heat the substrate when the temperature of the substrate is lower than or equal to a predetermined temperature. Characterized in that.

The drive unit of the head of the inkjet printer of the present invention for achieving the above object is a discharge heater driving power applied when the temperature of the substrate is above a predetermined temperature, a substrate heater applied when the temperature of the substrate is above a predetermined temperature A driving power source, a plurality of discharge heaters for heating ink to discharge ink through the nozzle when the temperature of the substrate is higher than a predetermined temperature, and the temperature of the substrate in response to the discharge enable signal; In this case, the discharge heater driving power is supplied to the discharge heater, and when the temperature of the substrate is lower than a predetermined temperature, a plurality of power transistors are provided to heat the substrate using the substrate heater driving power. do.

Each of the plurality of discharge heaters of the driving unit of the head of the inkjet printer of the present invention for achieving the above object is connected between the discharge heater driving power source and the substrate heater driving power source, and each of the plurality of power transistors is the And a gate to which a discharge enable signal is applied, and is connected between the substrate heater driving power source and a ground voltage.

The driving portion of the head of the inkjet printer of the present invention for achieving the above object is connected to the plurality of groups having the plurality of discharge heaters and the plurality of power transistors, and between the plurality of groups, the substrate Is connected to the source terminal of the power transistors of the front end groups to a ground voltage. If the temperature of the substrate is less than a predetermined temperature, the source terminals of the power transistors of the front end groups are connected to the next group. And a switch unit connected to the drain terminals of the power transistors.

Each of the plurality of discharge heaters of each of the plurality of groups of the driving unit of the head of the inkjet printer of the present invention for achieving the above object is connected between the discharge heater driving power source and the power transistor, and the plurality of powers Each of the transistors includes a gate to which the discharge enable signal is applied, and is connected between the plurality of switch units, and the substrate heater driving power is applied to a drain terminal of each of the first group of power transistors, and the last group The ground voltage is connected to the source terminal of each of the power transistors of the.

Hereinafter, the head of the inkjet printer of the present invention will be described with reference to the accompanying drawings.

3 shows one group of the discharge heater driving circuit of the inkjet printer head of the present invention, wherein the plurality of discharge heaters R1, R2, ..., Rn and the plurality of power transistors FET1, FET2, ..., FETn In Fig. 3, V1 denotes a discharge heater driving voltage, V2 denotes a substrate heater driving voltage, and S1, S2,. And Sn each represent a discharge enable signal.

The operation of the circuit shown in FIG. 3 is as follows.

When the temperature of the substrate is higher than the predetermined temperature, the substrate heater driving voltage V2 is not applied, and therefore, the same operation as that shown in FIG. That is, in response to the discharge enable signals S1, S2, ..., Sn, the corresponding power transistors FET1, FET2, ..., FETn are turned on, and the discharge heaters R1, R2, corresponding to the turned on power transistors are turned on. ..., Rn) is operated so that ink is discharged through the nozzle.

When the temperature of the substrate is lower than the predetermined temperature, the substrate heater driving voltage V2 is applied. The discharge enable signals S1, S2, ..., Sn are subsequently enabled sequentially or simultaneously. Accordingly, current flows through the power transistors FET1, FET2,..., FETn, and there is no voltage drop by the discharge heaters R1, R2,..., Rn, and thus, the power transistors FET1, FET2, ..., FETn operates as a substrate heater.

That is, since the power transistors FET1, FET2, ..., FETn each have their own resistive components, heat is generated when a constant current flows. In the present invention, when the substrate temperature is lower than the predetermined temperature, the power transistors FET1, FET2, ..., FETn are used as the substrate heater.

FIG. 4 is a view for explaining the wiring of the discharge heater driving circuit of the printer head of the present invention shown in FIG. 3, wherein the line filled with dots is a line arranged in one layer, and the line filled with diagonal lines is a line arranged in two layers. Respectively.

Referring to Figure 4 describes the wiring method of the print head of the present invention.

The substrate heater driving voltage V2 is applied through a plurality of wires arranged in two layers. These wires are connected to the wires arranged on the first layer through vias, respectively, and are connected to each of the power transistors FET1, FET2, ..., FETn.

The discharge heater driving voltage V1 is applied through the wirings arranged on the two layers. This wiring is connected to the wirings arranged on the first floor via vias and to the heaters R1, R2, ..., Rn.

FIG. 5 is a circuit diagram showing the discharge heater driving circuit of the inkjet printhead of the present invention, and is composed of three groups G1, G2, and G3 and two selection circuits 10 and 20. FIG. Each of the groups G1, G2, and G3 includes a plurality of discharge heaters R11 to R1n, or R21 to R2n, or R31 to R3n, and a plurality of power transistors FET11 to FET1n, or FET21 to FET2n, or And FETs 31 to FET3n, and the selection circuits 10 and 20 are each composed of a plurality of switching means 10-1 to 10-n, or 20-1 to 20-n.

In Fig. 5, V11, V12, and V13 denote discharge heater driving voltages, and V2 denotes substrate heater driving voltages, respectively.

In FIG. 5, HS is a temperature sensing signal enabled when the substrate temperature of the print head is below a predetermined temperature, and S1, S2,... , Sn is a discharge enable signal.

The operation of the circuit diagram shown in FIG. 5 is as follows.

Operations of the groups G1, G2, and G3 are the same as those described with reference to FIG. 3. However, the corresponding discharge heater driving voltages V11, V12, and V13 are applied to the groups G1, G2, and G3, and the second group G2 and the third group G3 are the substrate heater driving voltages V2. ) Is supplied from the switching means of the selection circuits 10 and 20.

The selection circuits 10 and 20 respectively connect one end of the power transistors FET11 to FET1 or FET21 to FET2n of the group G1 and G2 in front of the ground voltage or the next stage in response to the temperature sensing signal HS. It is connected to one end of the group of power transistors FET21 to FET2n, or FET31 to FET3n.

That is, when the temperature sensing signal HS is enabled because the temperature of the substrate is lower than or equal to a predetermined temperature, the selection circuit 10 may include a source terminal of each of the power transistors FET11 to FET1n of the first group G1. The drain terminals of the power transistors FET21 to FET2n of the second group G2 are connected, and when the temperature sensing signal HS is disabled, the power transistors FET11 of the first group G1 are disabled. Each of the source terminals of FET1n) is connected to the ground voltage.

Similarly, when the temperature sensing signal HS is enabled, the selection circuit 20 also controls the power of the source terminal and the third group G3 of each of the power transistors FET21 to FET2n of the second group G2. When the drain terminal of each of the transistors FET31 to FET3n is connected, and the temperature sensing signal HS is disabled, the source of each of the power transistors FET21 to FET2n of the second group G2 is disabled. source) terminal is connected to the ground voltage.

That is, when the temperature of the substrate is less than or equal to a predetermined temperature, the power transistors FET1x, FET2x, and FET3x to which the same discharge enable signals S1, S2, ..., Sn are applied are connected in series, and the temperature of the substrate is When the temperature is higher than a predetermined temperature, the source terminal of each of the power transistors FET11 to FET1n, FET21 to FET2n, and FET31 to FET3n is connected to the ground voltage. Therefore, when the temperature of the substrate becomes less than the predetermined temperature and the discharge enable signals S1, S2, ..., Sn are enabled, the current applied from the substrate heater driving voltage V2 is connected to the power transistors FET1x connected in series. , FET2x, and FET3x). In addition, when the temperature of the substrate is greater than or equal to a predetermined temperature, each of the groups G1, G2, and G3 drives the discharge heater by using the discharge heater driving voltages V11, V12, and V13 applied thereto.

In general, since the resistance value at the time of driving the power transistors is as small as 5 to 10 ohms (Ω), by connecting them in series, it is possible to shorten the heating time by making the amount of heat generated larger.                     

Fig. 6 is a diagram showing the layout of the substrate of the printhead of the present invention, comprising logic circuits 1-1, 1-2, substrate temperature sensors 2-1, 2-2, and a plurality of discharge heaters. The discharge heater region 3 configured, the address decoder regions 4-1 and 4-2 in which the address signal lines and the address decoder are arranged, and the power transistor regions 5-1 and 5-2 in which the plurality of power transistors are arranged. Consists of. In FIG. 6, V1 represents a discharge heater driving voltage, and V2 represents a substrate heater driving voltage, respectively.

The function of the circuits and regions shown in FIG.

The logic circuits 1-1 and 1-2 receive a signal input from an external printer ASIC through a pad, decode the signal, and transmit an address signal to the address decoder region 4-1 ,. Output via the address line arranged in 4-2).

Address decoders arranged in the address decoder areas 4-1 and 4-2 decode the address signal and output a discharge enable signal.

The substrate temperature sensors 2-1 and 2-2 sense the temperature of the print head substrate.

As described above, the power transistors disposed in the power transistor regions 5-1 and 5-2 are substrate heaters when the temperature of the substrate detected by the substrate temperature sensors 2-1 and 2-2 is equal to or less than a predetermined temperature. It acts as a, and if it is more than a predetermined temperature, it serves to drive the discharge heater disposed in the discharge heater region (3). The power transistor regions 5-1 and 5-2 are arranged to occupy most of the area of the substrate as shown in FIG. 6 to supply sufficient current to the discharge heater.

Each of the plurality of discharge heaters disposed in the discharge heater region 3 is operated by the power transistors so that ink is discharged through the nozzle.

That is, as mentioned above, in the case of the head of the conventional inkjet printer, since the substrate heater which raises the temperature of a board | substrate when the temperature of a board | substrate is low was arrange | positioned at the outer side of a printhead board | substrate, the board | substrate could not be heated evenly. In addition, it took a long time to heat up to the discharge heater region 3. However, in the case of the head of the inkjet printer of the present invention, the substrate is heated by using power transistors, which occupy most of the area at the center of the substrate, so that the substrate can be heated evenly, and also to the discharge heater region 3. The time required for heating is shortened.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Therefore, the head of the inkjet printer of the present invention can heat the substrate evenly when the temperature of the head substrate is low, and the heating time is also shortened.

Claims (5)

A logic unit configured to output a discharge enable signal in response to an input signal input from the outside; A substrate temperature sensor for sensing a temperature of the substrate; And In response to the temperature of the substrate detected by the substrate temperature sensor and the discharge enable signal, ink is discharged through a nozzle when the temperature of the substrate is greater than or equal to a predetermined temperature, and when the temperature of the substrate is less than or equal to a predetermined temperature, A head of the inkjet printer, characterized in that it comprises a drive unit for heating the. The method of claim 1, wherein the driving unit A discharge heater driving power source applied when the temperature of the substrate is greater than or equal to a predetermined temperature; A substrate heater driving power source applied when the temperature of the substrate is greater than or equal to a predetermined temperature; A plurality of discharge heaters for heating the ink to discharge the ink through the nozzle when the temperature of the substrate is greater than or equal to a predetermined temperature; And The discharge heater driving power is supplied to the discharge heater when the temperature of the substrate is higher than or equal to a predetermined temperature in response to the discharge enable signal. When the temperature of the substrate is lower than or equal to the predetermined temperature, the substrate heater driving power is turned off. And a plurality of power transistors for heating the substrate using the head of the inkjet printer. The method of claim 2, wherein the driving unit Each of the plurality of discharge heaters is connected between the discharge heater driving power source and the substrate heater driving power source, Each of the plurality of power transistors has a gate to which the discharge enable signal is applied, and is connected between the substrate heater driving power supply and a ground voltage. The method of claim 2, wherein the driving unit A plurality of groups including the plurality of discharge heaters and the plurality of power transistors; And A connection between the plurality of groups, when the temperature of the substrate is greater than or equal to a predetermined temperature, the source terminals of the power transistors of the shear groups to ground voltage; and when the temperature of the substrate is less than or equal to a predetermined temperature, the shear group And a plurality of switch portions connecting a source terminal of each of the power transistors to a drain terminal of each of the corresponding power transistors of a next group. The method of claim 4, wherein each of the plurality of groups Each of the plurality of discharge heaters is connected between the discharge heater driving power source and the power transistor, Each of the plurality of power transistors has a gate to which the discharge enable signal is applied, and is connected between the plurality of switch units, The substrate heater driving power is applied to a drain terminal of each of the first group of power transistors, and a ground voltage is connected to a source terminal of each of the last group of power transistors.

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