JP2010188578A - Inkjet recorder, and voltage control circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder and a voltage control circuit, capable of eliminating a useless electric power consumption generated when driving a piezoelectric head, to attain a low electric power consumption. <P>SOLUTION: This inkjet recorder for driving the piezoelectric head to deliver a liquid droplet, and for forming an image on a recording medium, includes a temperature detecting means for detecting a temperature in the vicinity of the piezoelectric head, a step-up means for stepping up a voltage supplied to the piezoelectric head, and a control means for determining whether the temperature detected by the temperature detecting means is a temperature lower than a prescribed threshold value, and the step-up means steps up the voltage supplied to the piezoelectric head, when the control means determines that the temperature detected by the temperature detecting means is the temperature lower than the prescribed threshold value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet recording apparatus that drives a piezoelectric head to eject droplets to form an image on a recording medium, and a voltage control circuit that controls a voltage supplied to the piezoelectric head.

  2. Description of the Related Art Conventionally, there is an ink jet recording apparatus that forms an image on a recording medium by driving a piezoelectric head to eject droplets. The drive voltage supplied from the ink jet recording apparatus main body to the piezoelectric head is normally supplied to the piezoelectric head via an amplifier circuit.

  The output voltage of the amplifier circuit (piezoelectric head drive voltage) needs to be a voltage sufficient to drive the piezoelectric head. Therefore, the voltage supplied to the amplifier circuit is fixed at a high voltage in accordance with the low temperature environment that consumes the most power. The low temperature environment is a case where the temperature around the piezoelectric head is low. In a low temperature environment, the lower the temperature around the piezoelectric head, the lower the fluidity of the ink. Therefore, in order to discharge droplets to the piezoelectric head, a stronger pressure is required than at normal temperature or high temperature. For this reason, in the conventional ink jet recording apparatus, the voltage at which the piezoelectric head can be driven in a low temperature environment is fixed to ensure the operation in the low temperature environment.

  Patent Documents 1 and 2 disclose techniques related to power saving of the power supply of the image forming apparatus.

  When the temperature in the vicinity of the piezoelectric head is normal or high, the driving voltage of the piezoelectric head may be lower than that in the vicinity of the piezoelectric head. Therefore, as described above, when the voltage supplied to the amplifier circuit is fixed to a voltage that guarantees operation in a low temperature environment, the difference between the fixed voltage and the temperature near the piezoelectric head is normal or high. The voltage is wasted as heat of the amplifier circuit. Further, when the amplifier circuit generates heat, this heat generation increases the temperature in the ink jet recording apparatus, which may reduce the reliability of other components in the ink jet recording apparatus.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an ink jet recording apparatus and voltage control capable of reducing power consumption while eliminating waste of power generated when driving a piezoelectric head. An object is to provide a circuit.

  The present invention employs the following configuration in order to achieve the above object.

The present invention is an ink jet recording apparatus that drives a piezoelectric head to eject droplets to form an image on a recording medium, and includes a temperature detection unit that detects a temperature in the vicinity of the piezoelectric head;
Boosting means for boosting the voltage supplied to the piezoelectric head, and control means for judging whether or not the temperature detected by the temperature detection means is lower than a predetermined threshold value. When it is determined by the means that the temperature detected by the temperature detecting means is lower than the predetermined threshold, the boosting means boosts the voltage supplied to the piezoelectric head.

  The ink jet recording apparatus of the present invention is disposed in front of the piezoelectric head, and includes an amplifier circuit that amplifies the voltage supplied to the piezoelectric head, and the boosting unit supplies the voltage supplied to the amplifier circuit. Is configured to boost.

  In the ink jet recording apparatus according to the aspect of the invention, the boosting unit may apply the first voltage necessary for driving the piezoelectric head when the temperature in the vicinity of the piezoelectric head is equal to or higher than the predetermined threshold. When the temperature in the vicinity is lower than the predetermined threshold, the voltage is increased to the second voltage necessary for driving the piezoelectric head.

  Further, the ink jet recording apparatus of the present invention is supplied with the first voltage and the second voltage, and outputs the first voltage or the second voltage as a voltage supplied to the piezoelectric head. And the voltage switching means outputs the second voltage when the temperature detected by the temperature detecting means is determined to be lower than the predetermined threshold, and the temperature detecting means When it is determined that the detected temperature is equal to or higher than the predetermined threshold, the first voltage is output.

  In the ink jet recording apparatus of the present invention, the boosting unit boosts the voltage supplied to the piezoelectric head with reference to the output of the temperature detecting unit.

  The ink jet recording apparatus of the present invention has a table in which a temperature in the vicinity of the piezoelectric head and a boost value of a voltage supplied to the piezoelectric head are associated with each other, and the control means is detected by the temperature detecting means. By referring to the table from the measured temperature, the boosting value is set in the boosting means.

  Further, in the ink jet recording apparatus of the present invention, the boosting unit stops boosting when a voltage conversion loss generated in the boosting unit becomes larger than a voltage difference between the first voltage and the second voltage, The image forming speed by the piezoelectric head is reduced by the upper control means.

  The present invention relates to a voltage control circuit for controlling a voltage supplied to a piezoelectric head for discharging ink stored in an ink liquid chamber as a droplet from a nozzle hole onto a recording medium, and a temperature in the vicinity of the piezoelectric head. Temperature detecting means for detecting the voltage, boosting means for boosting the voltage supplied to the piezoelectric head, and control means for determining whether or not the temperature detected by the temperature detecting means is lower than a predetermined threshold value. And when the temperature detected by the temperature detecting means is lower than the predetermined threshold by the control means, the boosting means boosts the voltage supplied to the piezoelectric head. It was set as the structure to do.

  According to the present invention, it is possible to reduce wasteful power consumption while driving the piezoelectric head and reduce power consumption.

FIG. 2 is a diagram illustrating an amplifier circuit 10 disposed in front of a piezoelectric head 20. FIG. 6 is a diagram for explaining a relationship between a driving voltage of the piezoelectric head 20 and a temperature. It is a figure explaining the voltage control circuit 30 of 1st embodiment of this invention. 4 is a diagram illustrating an example of a boosting stage table 40. FIG. FIG. 6 is a diagram illustrating an example of a waveform in which the voltage partially increases in the driving voltage of the piezoelectric head 20. It is a figure explaining the voltage control circuit 30A of 2nd embodiment of this invention. It is a figure explaining the voltage control circuit 30B of 3rd embodiment of this invention. It is a figure explaining the voltage control circuit 30C of 4th embodiment of this invention. It is a perspective view explaining an inkjet recording device. It is a side view explaining the mechanism part of an inkjet recording device.

  The present invention boosts the voltage supplied to an amplifier circuit and temperature detecting means for detecting the temperature in the vicinity of a piezoelectric head (piezoelectric element array) included in an ink jet recording apparatus that discharges droplets to form an image on a recording medium. When the temperature in the vicinity of the piezoelectric head is low, the voltage boosted by the boosting means is supplied to the piezoelectric head via the amplifier circuit.

  First, prior to the description of the embodiment of the present invention, an amplifier circuit provided in the front stage of the piezoelectric head of the ink jet recording apparatus will be described. FIG. 1 is a diagram for explaining an amplifier circuit 10 disposed in front of the piezoelectric head 20.

  The amplifier circuit 10 shown in FIG. 1 is a class B push-pull amplifier circuit. The amplifier circuit 10 includes an operational amplifier 11, an N-channel power transistor M1 (hereinafter referred to as transistor M1), and a P-channel power transistor M2 (hereinafter referred to as transistor M2). A drive waveform signal for driving the piezoelectric head 20 is input to the input of the operational amplifier 11 from a host control means for controlling the ink jet recording apparatus main body. The output of the operational amplifier 11 is connected to the bases of the transistors M1 and M2.

  A supply voltage Vh, which is a voltage supplied to the amplifier circuit 10, is applied to the collector of the transistor M1. The emitter of the transistor M1 is connected to the emitter of the transistor M2, and the collector of the transistor M2 is grounded. The voltage at the connection point between the emitter of the transistor M1 and the emitter of the transistor M2 is supplied to the piezoelectric head 20 as the output voltage Vo of the amplifier circuit 10.

  The amplifier circuit 10 drives the piezoelectric head 20 with the output current Io and the output voltage Vo. In the amplifier circuit 10, the collector loss of the transistor M1 is (Vh−Vo) × Io.

  Here, the relationship between the drive voltage and temperature of the piezoelectric head 20 will be described with reference to FIG. FIG. 2 is a diagram for explaining the relationship between the driving voltage of the piezoelectric head 20 and the temperature.

  A waveform A in FIG. 2 shows the drive voltage of the piezoelectric head 20 when the temperature in the vicinity of the piezoelectric head 20 is low (hereinafter, low temperature). A waveform B in FIG. 2 shows the driving voltage of the piezoelectric head 20 when the temperature in the vicinity of the piezoelectric head 20 is normal temperature or high temperature (hereinafter, normal temperature or high temperature).

  In FIG. 2, a voltage necessary for driving the piezoelectric head 20 reliably at a low temperature (hereinafter referred to as a required driving voltage at a low temperature) is defined as a voltage Vth, and a voltage necessary for driving the piezoelectric head 20 at a normal temperature or a high temperature ( Hereinafter, the required drive voltage at normal temperature) was defined as voltage Vhj. As can be seen from FIG. 2, the voltage Vth is higher than the voltage Vhj.

  In the ink jet recording apparatus, the required drive voltage Vth at the low temperature is set as the supply voltage Vh of the amplifier circuit 10 in order to guarantee the operation at the low temperature.

  Therefore, the collector loss at normal temperature or high temperature is (Vhj−Vo) × Io + (Vht−Vhj) × Io, and (Vht−Vhj) × Io is a useless loss.

  The embodiment of the present invention eliminates the above-mentioned useless loss and reduces power consumption.

(First embodiment)
FIG. 3 is a diagram illustrating the voltage control circuit 30 according to the first embodiment of the present invention.

  The voltage control circuit 30 according to the present embodiment is mounted on an ink jet recording apparatus 100 (described later) on which the piezoelectric head 20 is mounted.

  The voltage control circuit 30 includes a control unit 31, a boost converter 32, a voltage switching circuit 33, and a thermistor 34.

  The voltage control circuit 30 of the present embodiment is always supplied with the required drive voltage Vhj at normal temperature. In the voltage control circuit 30 of this embodiment, the thermistor 34 detects the temperature of the piezoelectric head 20, and the control unit 31 determines the temperature state of the piezoelectric head 20. When the temperature of the piezoelectric head 20 is determined to be normal or high, the control unit 31 supplies the piezoelectric head 20 with the required drive voltage Vhj at normal temperature. When the temperature of the piezoelectric head 20 is determined to be low, the control unit 31 is required at normal temperature. The drive voltage Vhj is boosted to the required drive voltage Vth at a low temperature by the boost converter 32 and supplied to the piezoelectric head 20. For example, the control unit 31 of the present embodiment determines that the temperature near the piezoelectric head 20 is 30 ° C. or higher, and determines that the temperature near the piezoelectric head 20 is 16 ° C. or higher and lower than 30 ° C. is normal temperature. However, a case where the temperature in the vicinity of the piezoelectric head 20 is less than 16 ° C. may be determined as a low temperature.

  In the present embodiment, with the above configuration, the low-temperature required drive voltage Vth, which is higher than the normal-time required drive voltage Vhj, is supplied only when the piezoelectric head 20 is at a low temperature. Therefore, in the present embodiment, it is possible to eliminate wasteful loss and reduce power consumption in the operation at normal temperature with the longest operation time.

  In the voltage control circuit 30, the output signal from the thermistor 34 is supplied to the control unit 31. The output signal of the thermistor 34 is supplied to an ADC (analog / digital converter) 35 of the control unit 31. A control signal output from the control unit 31 is supplied to the boost converter 32 and the voltage switching circuit 33.

  The boost converter 32 is supplied with the required drive voltage Vhj at normal temperature supplied to the voltage control circuit 30 and boosts the required drive voltage Vhj at normal temperature based on the control signal supplied from the control unit 31. The output of the boost converter 32 is supplied to the voltage switching circuit 33.

  The voltage switching circuit 33 is supplied with the drive voltage Vhj required at normal temperature and the voltage output from the boost converter 32. Based on the control signal supplied from the control unit 31, the voltage switching circuit 33 outputs either the drive voltage Vhj required at normal temperature or the voltage output from the boost converter 32.

  The voltage output from the voltage switching circuit 33 is supplied to the amplifier circuit 10 as the output voltage of the voltage control circuit 30. That is, the output voltage of the voltage control circuit 30 becomes the supply voltage Vh to the amplifier circuit 10. The output voltage Vo of the amplifier circuit 10 is supplied to the piezoelectric head 20 to drive the piezoelectric head 20.

  The control unit 31 according to the present embodiment includes a boost stage table 40 that associates the temperature of the thermistor 34 with the boost value of the boost converter 32. After the output of the thermistor 34 is converted into digital data by the ADC, the control unit 31 refers to the boosting step table 40 and determines whether or not to boost the required drive voltage Vhj at normal temperature. When it is determined that the required drive voltage Vhj at normal temperature is boosted, the control unit 31 outputs a control signal to the boost converter 32 and sets a boost value in the boost converter 32.

  FIG. 4 is a diagram for explaining an example of the boosting step table 40. In the step-up stage table 40 shown in FIG. 4, the case where the temperature of the piezoelectric head 20 is 15 ° C. or less is set as a low temperature.

  In the step-up step table 40, when the temperature detected by the thermistor 34 is 1 to 5 ° C., the required drive voltage Vhj at normal temperature is increased to AV, and when the temperature is 6 to 10 ° C., the required drive voltage Vhj at normal temperature is increased to BV. When the temperature is 11 to 15 ° C., the required driving voltage Vhj at normal temperature is boosted to CV, and when the temperature is 16 ° C. or higher, it is determined that the normal temperature is not increased. The step-up stage table 40 is stored in, for example, a storage unit (not shown) included in the control unit 31.

  Returning to FIG. 3, the voltage switching circuit 33 of the present embodiment includes a diode D and a switch SW. The drive voltage Vhj required at room temperature supplied to the voltage switching circuit 33 is supplied to the diode D. The output voltage of the boost converter 32 supplied to the voltage switching circuit 33 is supplied to one end of the switch SW. The other end of the switch SW is connected to the output of the diode D, and the output of the diode D is output as the output voltage of the voltage switching circuit 33, that is, the supply voltage Vh to the amplifier circuit 10. The switch SW is turned on / off by a control signal from the control unit 31.

  When the switch SW is turned off by the control signal, the voltage switching circuit 33 outputs the required drive voltage Vhj at normal temperature. When the switch SW is turned on by the control signal, the voltage switching circuit 33 outputs the output voltage of the boost converter 32.

  The thermistor 34 according to the present embodiment is incorporated in the piezoelectric head 20 and detects the temperature around the piezoelectric element constituting the piezoelectric head 20.

  The operation of the voltage control circuit 30 of this embodiment will be described below.

  First, the case where the temperature of the piezoelectric head 20 is low will be described.

  In the voltage control circuit 30 of the present embodiment, for example, when the temperature detected by the thermistor 34 is 6 ° C., the control unit 31 refers to the boosting stage table 40 and sets the boost value BV for the boost converter 32. . At the same time, the control unit 31 supplies a control signal for turning on the switch SW to the voltage switching circuit 33.

  In the voltage control circuit 30, the boost converter 32 boosts the required drive voltage Vhj at normal temperature based on the set boost value to obtain the required drive voltage Vth at low temperature and outputs it to the voltage switching circuit 33. In the voltage switching circuit 33, since the switch SW is turned on, the necessary drive voltage Vth is output at a low temperature. The outputted low-temperature necessary drive voltage Vth becomes the supply voltage Vh of the amplifier circuit 10. The drive voltage Vth required at low temperature is amplified to a voltage sufficient to drive the piezoelectric head 20 in the amplifier circuit 10 and supplied to the piezoelectric head 20.

  Next, a case where the temperature of the piezoelectric head 20 is normal temperature will be described.

  In the voltage control circuit 30 of the present embodiment, for example, when the temperature detected by the thermistor 34 is 20 ° C., the control unit 31 refers to the boosting stage table 40 and determines that boosting by the boosting converter 32 is not performed. At the same time, the control unit 31 supplies a control signal for turning off the switch SW to the voltage switching circuit 33.

  The voltage switching circuit 33 outputs the required drive voltage Vhj at normal temperature because the switch SW is off. The output drive voltage Vhj required at normal temperature is amplified to a voltage sufficient to drive the piezoelectric head 20 in the amplifier circuit 10 and supplied to the piezoelectric head 20.

  The case where the temperature of the piezoelectric head 20 is high is the same as the case where the temperature of the piezoelectric head 20 is normal because no pressure is increased.

  As described above, according to the present embodiment, the necessary drive voltage Vth at low temperature is not always supplied to the amplifier circuit 10, and power consumption is reduced by eliminating useless loss in the operation at room temperature with the longest operation time. Can be reduced.

  Further, in the present embodiment, heat generation due to useless loss does not occur in the amplifier circuit 10, so that an increase in temperature in the ink jet recording apparatus 100 can be suppressed and reliability can be improved.

  The voltage normally supplied to the amplifier circuit 10 is a voltage that is commonly supplied to other components such as a motor driver and a fan included in the inkjet recording apparatus 100. Therefore, when the voltage supplied to the amplifier circuit 10 is high, it is necessary to select other components having a high rated voltage, and there are problems such as an increase in cost and a narrow selection of components.

  In the present embodiment, the voltage control circuit 30 sets the voltage that is constantly supplied to the amplifier circuit 10 to the room temperature required drive voltage Vhj that is lower than the low temperature required drive voltage Vth, whereby the above problem can be solved. That is, according to the present embodiment, a part that uses the voltage supplied to the amplifier circuit 10 in common can be a part with a low rated voltage, and the choice of parts can be expanded.

(Second embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. The second embodiment of the present invention is different from the first embodiment in that the case where the drive voltage to the piezoelectric head 20 is partially increased is taken into consideration. Therefore, in the following description of the second embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment will be used in the description of the first embodiment. The same reference numerals as those used are assigned, and the description thereof is omitted.

  The piezoelectric head 20 may require a partially large driving voltage when the writing speed is increased. In this case, the piezoelectric head 20 is supplied with a driving voltage having a partially increased voltage as shown in FIG. FIG. 5 is a diagram illustrating an example of a waveform in which the voltage partially increases in the driving voltage of the piezoelectric head 20. It can be seen from the waveform shown in FIG. 5 that the drive voltage is partially increased.

  In the present embodiment, the drive voltage can be boosted only when necessary by setting the timing at which a large drive voltage is required in the control unit 31A in advance. The timing at which a large drive voltage is required is determined in advance from the characteristics of the piezoelectric head 20 and the like.

  FIG. 6 is a diagram illustrating a voltage control circuit 30A according to the second embodiment of the present invention.

  The voltage switching circuit 33A included in the voltage control circuit 30A of the present embodiment includes a switch SW1 instead of the switch SW. The switch SW1 included in the voltage switching circuit 33A of the present embodiment is, for example, an FET (Field effect transistor) switch.

  In addition, the timing at which a large drive voltage is required is set in advance in the control unit 31A of the present embodiment. The control unit 31A supplies a control signal for turning on the switch SW1 to the voltage switching circuit 33 according to the set timing.

  In the present embodiment, the above configuration can provide the same effects as those of the first embodiment.

(Third embodiment)
A third embodiment of the present invention will be described below with reference to the drawings. The third embodiment of the present invention is different from the first embodiment in that a comparator is provided in the control unit instead of the ADC. Therefore, in the following description of the third embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment will be used in the description of the first embodiment. The same reference numerals as those used are assigned, and the description thereof is omitted.

  FIG. 7 is a diagram illustrating a voltage control circuit 30B according to the third embodiment of the present invention.

  The control unit 31B of the present embodiment includes a comparator 36. In the present embodiment, the output of the thermistor 34 is supplied to the comparator 36. In this embodiment, the output of the thermistor 34 is supplied to the boost converter 32.

  The control unit 31B of this embodiment determines the temperature of the piezoelectric head 20 by the comparator 36 to which the output of the thermistor 34 is supplied. When it is determined that the temperature of the piezoelectric head 20 is low, the control unit 31B supplies a control signal for turning on the switch SW to the voltage switching circuit 33. For example, in the control unit 31B of the present embodiment, a reference voltage serving as a reference for determining that the temperature of the piezoelectric head 20 is low is supplied to one input of the comparator 36, and an output of the thermistor 34 is supplied to the other input of the comparator 36. You may do it. Then, on / off of the switch SW of the voltage switching circuit 33 may be controlled using the output signal of the comparator 36 as an output signal.

  In the boost converter 32A of the present embodiment, the boost value is set based on the output of the thermistor 34. In the boost converter 32A of the embodiment, for example, when the output of the thermistor 34 is equal to or higher than a predetermined value, the required drive voltage Vhj at normal temperature may be boosted to the required drive voltage Vth at low temperature. Thus, in the present embodiment, on / off control of the switch SW of the voltage switching circuit 33 and the setting of the boost value of the boost converter 32A are performed based on the output of the thermistor 34. Therefore, in this embodiment, it is not necessary to provide an ADC in the control unit 31B, which can contribute to the cost reduction of the voltage control circuit 30B.

  This embodiment can obtain the same effects as those of the first embodiment with the above configuration.

(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. The fourth embodiment of the present invention is different from the first embodiment in that the output voltage of the boost converter is a supply voltage to the amplifier circuit without providing a voltage switching circuit. Therefore, in the following description of the third embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment will be used in the description of the first embodiment. The same reference numerals as those used are assigned, and the description thereof is omitted.

  FIG. 8 is a diagram illustrating a voltage control circuit 30C according to the fourth embodiment of the present invention.

  The voltage control circuit 30 </ b> C of the present embodiment includes a control unit 31, a boost converter 32, and a thermistor 34. The controller 31 is supplied with the output of the thermistor 34. Boost converter 32 is set with a boost value by a control signal supplied from control unit 31 and boosts drive voltage Vhj required at room temperature. The output voltage of the boost converter 32 is supplied to the amplifier circuit 10 as the supply voltage Vh of the amplifier circuit 10.

  Note that the control unit 31 of the present embodiment may set a boost value to the boost converter 32 with reference to the boost stage table 40 as shown in FIG.

  Boosting by the boost converter 32 of the present embodiment is effective in the range of voltage conversion loss of the boost converter 32 ≦ (Vth−Vh) × Io. This is because as the temperature around the piezoelectric head 20 decreases, the difference between the drive voltage Vth required at low temperatures and the supply voltage Vh decreases. This is because if the voltage conversion loss of the boost converter 32 becomes larger than the difference voltage between the required drive voltage Vth and the supply voltage Vh at low temperature, the difference between the difference voltage and the voltage conversion loss of the boost converter 32 becomes useless loss. . In the present embodiment, if the voltage conversion loss of the boost converter 32 is not in the range of (Vth−Vh) × Io, the image forming speed by the piezoelectric head 20 is reduced without maintaining the boost and the print quality is maintained.

  In the present embodiment, due to the above configuration, the same effects as those of the first embodiment can be obtained even if the voltage switching circuit 33 is not provided. Further, in the present embodiment, the voltage switching circuit 33 is unnecessary, which can contribute to a reduction in current consumption and cost of the voltage control circuit 30C.

  Here, an ink jet recording apparatus on which the control circuit described in each of the above embodiments is mounted will be described with reference to FIGS. FIG. 9 is a perspective view for explaining the ink jet recording apparatus, and FIG. 10 is a side view for explaining a mechanism part of the ink jet recording apparatus.

  The ink jet recording apparatus 100 includes a carriage 160 that can move in the main scanning direction inside the ink jet recording apparatus 100, a recording head 107 that includes a cartridge 105 mounted on the carriage, a drive device that drives and controls the recording head 107, and a recording head 107. The printing mechanism unit 110 and the like are housed. In the recording head 107, an ink liquid discharge device held by a carriage 160 is disposed below the cartridge 105, and the piezoelectric head 20 is mounted on the ink discharge device.

  A paper feed cassette (or a paper feed tray) 120 in which a large number of recording media (paper sheets) 40 can be loaded from the front side can be detachably attached to the lower part of the inkjet recording apparatus 100.

  Further, the inkjet recording apparatus 100 can turn over the manual feed tray 130 for manually feeding the paper 40. The inkjet recording apparatus 100 takes in the paper 40 fed from the paper feed cassette 120 or the manual feed tray 130, records a required image by the printing mechanism unit 110, and then discharges the paper onto a paper discharge tray 150 mounted on the rear side. To do.

  Further, during recording, the ink jet recording apparatus 100 drives the recording head 107 according to the image signal while moving the carriage 160, thereby ejecting ink onto the stopped paper 40 to record one line. After the predetermined amount 40 is conveyed, the next line is recorded. The inkjet recording apparatus 100 ends the recording operation and discharges the paper 40 by receiving a recording end signal or a signal that the trailing edge of the paper 40 has reached the recording area.

  As mentioned above, although this invention has been demonstrated based on each embodiment, this invention is not limited to the requirements shown in the said embodiment. With respect to these points, the gist of the present invention can be changed without departing from the scope of the present invention, and can be appropriately determined according to the application form.

  INDUSTRIAL APPLICABILITY The present invention can be used for an inkjet recording apparatus that forms an image on a recording medium by driving a piezoelectric head to eject droplets and a voltage control circuit that controls a voltage supplied to the piezoelectric head.

DESCRIPTION OF SYMBOLS 10 Amplification circuit 11 Operational amplifier 20 Piezoelectric head 30 Control circuit 31 Control part 32 Boost converter 33 Voltage switching circuit 34 Thermistor 35 ADC
36 Comparator 40 Boosting Step Table 100 Inkjet Recording Device

JP 2002-354802 A JP 2002-19232 A

Claims (8)

An inkjet recording apparatus that drives a piezoelectric head to discharge droplets and forms an image on a recording medium,
Temperature detecting means for detecting the temperature in the vicinity of the piezoelectric head;
Boosting means for boosting the voltage supplied to the piezoelectric head;
Control means for determining whether or not the temperature detected by the temperature detecting means is lower than a predetermined threshold,
An ink jet recording apparatus, wherein when the temperature detected by the temperature detecting means is determined by the control means to be lower than the predetermined threshold, the boosting means boosts the voltage supplied to the piezoelectric head. Arranged in front of the piezoelectric head, and having an amplifying circuit for amplifying a voltage supplied to the piezoelectric head;
The inkjet recording apparatus according to claim 1, wherein the booster boosts a voltage supplied to the amplifier circuit. The boosting means includes
When the temperature in the vicinity of the piezoelectric head is equal to or higher than the predetermined threshold, the first voltage required for driving the piezoelectric head is the temperature in the vicinity of the piezoelectric head is lower than the predetermined threshold. The ink jet recording apparatus according to claim 1 or 2, wherein the voltage is increased to a second voltage necessary for driving the piezoelectric head. Voltage switching means for supplying the first voltage and the second voltage and outputting the first voltage or the second voltage as a voltage supplied to the piezoelectric head;
The voltage switching means is
When it is determined that the temperature detected by the temperature detecting means is lower than the predetermined threshold, the second voltage is output,
The inkjet recording apparatus according to claim 3, wherein the first voltage is output when it is determined that the temperature detected by the temperature detection means is equal to or higher than the predetermined threshold.   5. The inkjet recording apparatus according to claim 1, wherein the boosting unit boosts a voltage supplied to the piezoelectric head with reference to an output of the temperature detection unit. A table in which a temperature in the vicinity of the piezoelectric head and a boost value of a voltage supplied to the piezoelectric head are associated with each other;
7. The ink jet recording apparatus according to claim 1, wherein the control unit refers to the table from the temperature detected by the temperature detection unit and sets a boost value in the boost unit. The boosting means includes
When the voltage conversion loss generated in the boosting means becomes larger than the voltage difference between the first voltage and the second voltage, the boosting is stopped,
The ink jet recording apparatus according to any one of claims 3 to 6, wherein an image forming speed by the piezoelectric head is reduced by an upper control means. A voltage control circuit for controlling a voltage supplied to a piezoelectric head for ejecting ink stored in an ink chamber as a droplet from a nozzle hole onto a recording medium,
Temperature detecting means for detecting the temperature in the vicinity of the piezoelectric head;
Boosting means for boosting the voltage supplied to the piezoelectric head;
Control means for determining whether or not the temperature detected by the temperature detecting means is lower than a predetermined threshold,
A voltage control circuit for boosting the voltage supplied to the piezoelectric head when the temperature detected by the temperature detecting means is determined by the control means to be lower than the predetermined threshold.

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