JP2002139385A - Temperature detection circuit and recording apparatus therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accurate temperature detection circuit at a low cost. SOLUTION: The temperature detection circuit includes a diode D1 servings as a temperature detection element; a noninverting amplifier Q1; a resistance R1 connected to a power supply at one end and to the anode of the diode and the noninverting input of the noninverting amplifier at the other end; and a resistance R2 connected to the anode of the diode and the noninverting input of the noninverting amplifier at one end and to the inverting input of the noninverting amplifier at the other end. Each value is set to satisfy the relationship R2=R1×(A-1). The value of a current flowing through the diode is thereby held constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting circuit and a recording apparatus including the same, and more particularly to a temperature detecting circuit suitable for a recording apparatus which performs recording by using thermal energy generated by a thermal energy converter. The present invention relates to a circuit and a recording device including the circuit.

[0002]

2. Description of the Related Art As an information output device in, for example, a word processor, a personal computer, a facsimile, etc., a printer which records desired information such as characters and images on a sheet-like recording medium such as paper or film is widely used. I have.

[0003] Various types of printing methods are known for printers. However, ink-jet printing is possible because non-contact printing is possible on printing media such as paper, colorization is easy, and quietness is high. In recent years, the method has attracted special attention. As a configuration, a recording head that ejects ink according to desired recording information is mounted, and recording is performed while reciprocating scanning in a direction perpendicular to the feeding direction of a recording medium such as paper. Are generally widely used because they are inexpensive and easy to miniaturize.

[0004] Among the ink jet systems, there is provided a means (for example, a heater) for generating thermal energy as energy used for discharging ink, and in the system in which a change in the state of the ink is caused by the generated thermal energy, the ink is used. Since the ejection characteristics depend on the temperature, it is effective to measure the temperature inside the print head to obtain appropriate ejection characteristics. Further, when the ink runs out or the nozzles are clogged, the ink does not flow and the recording head may be excessively heated. To prevent this, it is necessary to measure the temperature inside the recording head and take appropriate measures when the temperature rises.

The forward voltage Vf of the diode and the base-emitter voltage Vbe of the transistor have a temperature dependency, and can be used for temperature measurement. When it is desired to measure the temperature of a semiconductor element such as an IC, by utilizing these temperature characteristics, a diode or a transistor in a semiconductor circuit can be used as a temperature sensor.

Generally, a heater and a driving circuit of a recording head are formed on a semiconductor substrate as a semiconductor circuit. Therefore, it is easy to incorporate a diode or a transistor for temperature measurement on the substrate, which almost increases the cost. Also does not invite. Therefore, a diode or a transistor for temperature measurement is conventionally incorporated in the recording head and used as a temperature sensor.

[0007]

However, in order to accurately measure the temperature by using the change in the forward voltage Vf of the diode and the base-emitter voltage Vbe of the transistor, the current flowing through these elements must be measured. It needs to be constant. For this reason, a constant current circuit is conventionally used, but in order to obtain a stable constant current circuit, it is necessary to use a reference voltage generator or make the output have a high impedance. And its price rises.

The present invention has been made in view of the above situation, and has as its object to provide a low-cost temperature detection circuit with a simple configuration and a recording apparatus having the circuit.

[0009]

In order to achieve the above object, a temperature detecting circuit according to the present invention comprises a temperature detecting element, a non-inverting amplifier, one end connected to a power supply, and the other end connected to the output of the temperature detecting element. A first resistor connected to the non-inverting input of the non-inverting amplifier, one end connected to the output of the temperature detecting element and the non-inverting input of the non-inverting amplifier, and the other end connected to the inverting input of the non-inverting amplifier. And a second resistor connected to the temperature detecting element, and the values of the first and second resistors are determined so that the value of the current flowing through the temperature detecting element is constant.

The object of the present invention is also a recording apparatus provided with the temperature detecting circuit, comprising a recording head for performing recording using thermal energy generated by a thermal energy converter, wherein the temperature detecting element is provided. Is also achieved by a recording device formed on the same element substrate as the thermal energy converter.

According to the configuration of the temperature detecting circuit, the non-inverting amplifier has the function of amplifying the output of the temperature sensor and the function of flowing a constant current to the temperature sensor. A constant current can be passed through the sensor, and an accurate temperature detection circuit can be realized at low cost.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

In this specification, "recording" (sometimes referred to as "printing") refers not only to the formation of significant information such as characters and figures, but also to the perception of humans irrespective of significance. Regardless of whether or not the image has been exposed so as to be able to perform the process, the case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or a case where the medium is processed is also described.

The "recording medium" is not limited to paper used in a general recording apparatus, but is widely applicable to ink, such as cloth, plastic films, metal plates, glass, ceramics, wood, and leather. Things are also represented.

Further, the term “ink” (sometimes referred to as “liquid”) is to be interpreted as widely as the definition of “recording (printing)”, and by being applied on a recording medium, A liquid that can be used for forming an image, a pattern, a pattern, or the like, processing a recording medium, or processing ink (for example, coagulating or insolubilizing a colorant in ink applied to the recording medium) is used.

Further, the term "element substrate" used below does not indicate a mere substrate made of a silicon semiconductor, but indicates a substrate provided with each element, wiring, and the like.

Further, the expression "on the element substrate" used in the following description not only indicates the upper side of the element substrate but also the surface of the element substrate and the inside of the element substrate near the surface. The term "built-in" as used in the present invention is not a term indicating that each element is simply disposed on a substrate, but is a step of manufacturing a semiconductor circuit. This indicates that the device is integrally formed and manufactured on an element substrate by, for example, the method described above.

First, a typical overall configuration and a control configuration of a recording apparatus using a recording head according to the present invention described below will be described.

FIG. 2 is an external perspective view showing the outline of the configuration of an ink jet printer IJRA as a recording apparatus using the recording head of the present invention. In FIG. 2, the driving force transmission gear 500 is linked with the forward / reverse rotation of the driving motor 5013.
Lead screw 500 rotating through 9-5011
The carriage HC engaged with the spiral groove 5004 of FIG. 5 has a pin (not shown), and is supported by the guide rail 5003 and reciprocates in the directions of arrows a and b. On the carriage HC, an integrated type ink jet cartridge IJC containing a recording head IJH and an ink tank IT is mounted.

Reference numeral 5002 denotes a paper holding plate, and a carriage H
The recording paper P is pressed against the platen 5000 over the moving direction of C. Reference numerals 5007 and 5008 denote photocouplers, which are home position detectors for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013.

Reference numeral 5016 denotes a member for supporting a cap member 5022 for capping the front surface of the recording head IJH.
Reference numeral 15 denotes a suction device that suctions the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. 5
Reference numeral 017 denotes a cleaning blade. Reference numeral 5019 denotes a member which allows the blade to move in the front-rear direction. These members are supported by a main body support plate 5018. It goes without saying that the blade is not limited to this form, and a well-known cleaning blade can be applied to this embodiment.

Reference numeral 5021 denotes a lever for starting suction for recovery of suction, and a cam 5020 which engages with the carriage.
The driving force from the recovery motor is controlled by a known transmission mechanism such as clutch switching.

The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. If a desired operation is performed at the timing, any of the embodiments can be applied.

Next, a control configuration for executing the recording control of the above-described apparatus will be described.

FIG. 3 is a block diagram showing a configuration of a control circuit of the ink jet printer IJRA. In FIG. 3, 1 is a CPU, 2 is a ROM, 3 is a printer control IC, 4 is a USB interface, 5 is a parallel interface, 6 is RAM, 7 is a recording head, and 8 is E
EPROM, 9 is an amplification circuit, 10 is a carriage motor,
11 is a paper feed motor, 12 is an ASF motor, 13 is a recovery motor, 14 is a carriage motor driver, 15 is a paper feed motor driver, 16 is an ASF motor driver, 17 is a recovery motor driver, 18 is a carriage encoder,
9 is a paper feed encoder, 20 is a paper end sensor,
21 is an ASF sensor, 22 is a recovery sensor, 23 is a key switch, and 24 is an LED.

The CPU 1 controls the entire printer, and includes a processor for executing a program, a timer,
Built-in D converter and input / output port. ROM
2 incorporates programs executed by the CPU 1 and various data necessary for control. The printer control IC 3 is connected to the CPU 1 via a bus line, and controls the USB interface 4, the parallel interface 5, the RAM 6, the recording head IJH, and various motors based on instructions from the CPU 1. The USB interface 4 and the parallel interface 5 are connected to a host system such as a computer and receive recording data and commands. The RAM 6 is used for storing received data, image data, work data necessary for controlling the printer, and the like.

The recording head IJH is an ink jet head in which a plurality of ink jet nozzles are arranged, and is controlled by a printer control IC3. EEPR
The OM 8 is an electrically writable non-volatile memory, and stores setting information of the printer. The amplification circuit 9 amplifies the signal of the temperature sensor built in the recording head IJH and inputs the signal to the AD converter of the CPU 1. The carriage motor 10 is controlled by the printer control IC 3 and scans the carriage in the main scanning direction. The paper feed motor 11 is controlled by the printer control IC 3,
The recording medium is transported in the sub-scanning direction. The ASF motor 13 is controlled by the printer control IC 3 and feeds a recording medium from an auto seed feeder. The recovery motor 14 is controlled by the CPU 1 and performs recovery operations such as cleaning of the ejection surface of the recording head IJH and suction of ink. Carriage motor driver 14, paper feed motor driver 1
5. The ASF motor driver 16 and the recovery motor driver 17 drive each motor based on a motor control signal output from the CPU 1 or the printer control IC 3.

The carriage encoder 18 measures the scanning amount of the carriage. The paper feed encoder 19 measures the transport amount of the recording medium. The paper end sensor 20 detects the rear end of the recording medium. The ASF sensor 21 is used for positioning the ASF motor 13. The recovery sensor 22 is used for positioning the recovery motor 14. The key switch 23 includes a power key and a recovery key, and is used for turning on the power of the printer and recovering from an error state. LED 24 is 2
The light emitting diode of the color, the power supply status is indicated by a green LED, and the error status is indicated by an orange LED.

As described above, the ink tank IT and the recording head IJH may be integrally formed to constitute a replaceable ink cartridge IJC. However, the ink tank IT and the recording head IJH are separated. It may be configured so that only the ink tank IT can be replaced when the ink runs out.

FIG. 4 is an external perspective view showing the structure of an ink cartridge IJC in which the ink tank and the recording head can be separated. In the ink cartridge IJC, as shown in FIG. 4, the ink tank IT and the recording head IJH can be separated at the position of the boundary line K. Ink cartridge IJ
C is provided with an electrode (not shown) for receiving an electric signal supplied from the carriage HC when mounted on the carriage HC, and the electric signal drives the recording head IJH as described above. Then, the ink is ejected.

In FIG. 4, reference numeral 500 denotes an ink ejection port array. The ink tank IT is provided with a fibrous or porous ink absorber for holding ink.

FIG. 5 shows an equivalent circuit inside the recording head IJH. In FIG. 5, reference numeral 100 denotes a control circuit;
Denotes a heater driver, 102 denotes a heater, and 103 denotes a temperature sensor, all of which are formed on the same semiconductor substrate as an element base.

The control circuit 100 includes a shift register and a latch for storing drive data, and a decoder for selecting a drive nozzle. The drive data is sent from the printer control IC 3 to the data signal DATA and the clock signal CLK.
And serially transferred to the shift register in the control circuit. The stored driving data is the latch signal LT
B, the signal is transferred to the latch in the control circuit, and the heat signal H
A drive signal for the nozzle selected by the decoder based on the EB is output.

The heater driver 101 controls the energization of the corresponding heater 102 according to the drive signal. Heater 10
Reference numeral 2 denotes an electrothermal transducer disposed at each nozzle of the recording head. When the corresponding heater driver 101 is driven and energized from the heater power supply VH, the heater is heated and the ink foams, thereby causing the ink to flow from the nozzle. Drops are ejected.

The temperature sensor 103 is a diode disposed in the vicinity of the heater 102. The temperature sensor 103 utilizes the property that the forward voltage of the diode depends on the temperature, so that the anode terminal DI
It is used for detecting the temperature inside the print head based on the output from two output terminals A and the cathode side terminal DIK.

Hereinafter, the temperature detecting circuit of the present invention for detecting the temperature inside the recording head of the recording apparatus described above will be described.

FIG. 1 is a circuit diagram of a temperature detecting circuit according to an embodiment of the present invention. D1 is a diode used as a temperature sensor (temperature detecting element), Q1 is an operational amplifier used as a non-inverting amplifier, and Vcc is a power supply. R1 to R5 are resistors, and Vo indicates an output.

The resistor R1 and the diode D1 are connected in series to the power supply Vcc. The anode of the diode D1 is connected to the non-inverting input of the non-inverting amplifier Q1,
The cathode is grounded. The non-inverting amplifier Q1 amplifies the forward voltage of the diode sensor D1 to a level suitable for temperature measurement. The operating point and the amplification factor of the non-inverting amplifier Q1 are determined by the resistors R3, R4 and R5. The output Vo of the non-inverting amplifier Q1 and the anode of the diode D1 are connected by a resistor R2.

With the above configuration, the non-inverting amplifier Q
1 is input to an A / D converter inside the CPU 1. The CPU 1 can recognize the temperature inside the print head by performing an analog-to-digital conversion of the input signal using an AD converter.

The operation of the circuit shown in FIG. 1 will be described below.

Assuming that the forward voltage of the diode D1 is Vf, the output voltage Vo of the non-inverting amplifier Q1 is Vo = (1+ (R3 + R4) × R5 / (R3 × R4))
Vf−R5 / R3 × Vcc.

Here, 1+ (R3 + R4) × R5 / (R
If 3 × R4) is the amplification factor A of the non-inverting amplifier Q1, then Vo = A × Vf−R5 / R3 × Vcc.

The current I1 flowing through the resistor R1 and the current I2 flowing through the resistor R2 are respectively I1 = (Vcc-Vf) / R1 I2 = (Vo-Vf) / R2.

Since the current If flowing through the diode sensor D1 is the sum of I1 and I2, If = I1 + I2 = (1 / R1−R5 / (R3 × R2)) × Vcc− (R2−R1 × (A− 1)) Vf / (R1 × R2)

If the resistance value of R2 is set so that R2 = R1 × (A-1), the term of Vf is canceled out, and If = (1 / R1-R5 / (R3 × R2)) × Vcc, and If is constant regardless of Vf.

As described above, by setting R2 = R1 × (A-1), the current If flowing through the diode D1 is obtained.
Can be made constant irrespective of Vf, and the same effect as when a constant current circuit is used can be obtained.

As described above, according to the present embodiment,
A constant current can be supplied to the temperature sensor without requiring an independent constant current circuit, and a highly accurate temperature detection circuit can be realized at low cost.

As described above, since the discharge characteristics of the ink jet nozzle depend on the temperature, stable discharge characteristics can be obtained by changing the pulse width of the drive signal in accordance with the temperature of the recording head. Also, if the supply of ink is interrupted due to lack of ink or clogged nozzles, the drive heater of the print head will be in an empty state and the print head will overheat, and if the print operation continues, the print head will deteriorate. There is. Monitor the temperature of the recording head,
By stopping the recording operation when the temperature rises excessively,
Deterioration of the recording head can be prevented.

[0049]

[Other Embodiments] In the above embodiment, an example has been described in which only a diode as a sensor is formed on a semiconductor substrate of a recording head among components constituting a temperature detection circuit. All the components of the temperature detection circuit may be built on the same semiconductor substrate.
The D converter may be built on the same substrate.

The above-described embodiment is particularly provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for causing ink to be ejected even in an ink jet recording system. By using a method in which a change in the state of the ink is caused by energy, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding the nucleate boiling to the electrothermal transducer arranged corresponding to the sheet or the liquid path in which Since thermal energy is generated in the electrothermal transducer and film boiling occurs on the heat-acting surface of the recording head, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is valid.

By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angle liquid flow path) as disclosed in the above-mentioned respective specifications, The configurations described in U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which the heat acting surface is arranged in a bending region, are also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slot is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal transducers, or an opening for absorbing a pressure wave of thermal energy is discharged. A configuration based on JP-A-59-138461, which discloses a configuration corresponding to each unit, may be adopted.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by a combination of a plurality of recording heads as disclosed in the above specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition to the cartridge type recording head in which the ink tank is provided integrally with the recording head itself described in the above embodiment, the recording head is electrically connected to the apparatus main body by being mounted on the apparatus main body. A replaceable chip-type recording head, which enables a simple connection and supply of ink from the apparatus main body, may be used.

It is preferable to add recovery means for the print head, preliminary auxiliary means, and the like to the configuration of the printing apparatus described above, since the printing operation can be further stabilized. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof. It is also effective to provide a preliminary ejection mode for performing ejection that is different from printing, in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, and the recording head may be integrally formed or a combination of a plurality of recording heads. Alternatively, the apparatus may be provided with at least one of full colors by color mixture.

In the above-described embodiment, the description has been made on the assumption that the ink is a liquid. However, even if the ink solidifies at room temperature or lower, the ink that softens or liquefies at room temperature is used. Or, in the ink jet method, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range.
It is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy as energy for changing the state of the ink from the solid state to the liquid state, the temperature is positively prevented.
Alternatively, in order to prevent evaporation of the ink, an ink which solidifies in a standing state and liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used.

In such a case, ink is disclosed in JP-A-54-5
No. 6,847, or Japanese Patent Application Laid-Open No. 60-71260, in which the porous sheet is opposed to the electrothermal converter while being held as a liquid or solid substance in the concave portion or through hole of the porous sheet. It may be. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus including one device (for example, a copier, a facsimile) Device).

[0063]

As described above, according to the present invention, an independent constant current circuit is required because the non-inverting amplifier has both the function of amplifying the output of the temperature sensor and the function of flowing a constant current to the temperature sensor. This allows a constant current to flow through the temperature sensor without the need for a temperature sensor with high accuracy.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a temperature detection circuit according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a preferred embodiment of a recording apparatus according to the present invention.

FIG. 3 is a block diagram illustrating a control configuration of the printing apparatus of FIG. 2;

FIG. 4 is a diagram illustrating an ink jet cartridge of the recording apparatus of FIG. 2;

FIG. 5 is a circuit diagram showing an equivalent circuit of a recording head of the recording apparatus of FIG.

[Explanation of symbols]

 D1 Diode Q1 Non-inverting amplifier R1 to R5 Resistance

Claims (5)

[Claims] A temperature detecting element, a non-inverting amplifier, a first resistor having one end connected to a power supply, and the other end connected to an output of the temperature detecting element and a non-inverting input of the non-inverting amplifier; A second resistor having one end connected to the output of the temperature detection element and the non-inverting input of the non-inverting amplifier, and the other end connected to the inverting input of the non-inverting amplifier; 2. The temperature detection circuit according to claim 1, wherein the value of the resistor is set so that the value of the current flowing through the temperature detection element is constant. 2. When the gain of the non-inverting amplifier is A, the value of the first resistor is R1, and the value of the second resistor is R2, R2 = R1 × (A-1). The temperature detection circuit according to claim 1, wherein a relationship is established. 3. The temperature detection circuit according to claim 1, wherein the temperature detection element is a diode. 4. A recording apparatus comprising the temperature detection circuit according to claim 1, further comprising a recording head that performs recording by using thermal energy generated by a thermal energy converter. The recording apparatus, wherein the temperature detecting element is formed on the same element base as the thermal energy converter. 5. The recording apparatus according to claim 4, wherein the recording head is an inkjet recording head that performs recording by discharging ink.