JP2011110841A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device surely detecting the origin position of a carriage. <P>SOLUTION: The origin position of the carriage is determined by both of abutting of the carriage against a mechanical stopper and torque detection of a lifting motor. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to a carriage origin position detection method.

  In an ink jet recording apparatus, a recording head that discharges ink onto a recording medium is mounted on a carriage, and printing is performed as the carriage is moved by a drive motor. The movement of the carriage is controlled so that ink is ejected to a predetermined position of the recording medium with reference to a preset position, that is, the origin position. As a mechanism for detecting the origin position of the carriage, there is conventionally a mechanism that detects the increase in the current value of the drive motor after the stopper portion provided on the carriage hits the frame provided on the end of the main body (for example, Patent Document 1).

JP 60-021280 (page 3, Fig. 1)

  However, the detection method by the carriage abutment has a problem that even when the carriage stops at an unexpected position, the position is erroneously recognized as the origin position.

  In order to solve the above problems, an ink jet recording apparatus of the present invention includes a carriage that reciprocates by mounting a recording head that forms an image on a recording medium, a carriage control unit that reciprocates the carriage, Carriage load detecting means for detecting the load of the drive motor of the carriage, a first recording head elevating unit mounted on the carriage, and a second recording head elevating unit mounted on the frame of the printer, Elevating means for engaging and lowering the recording head when in position, elevating control means for elevating and driving the recording head, and elevating load detecting means for detecting the load of the elevating motor, The origin position of the carriage is determined based on detection results of the carriage load detection means and the lifting load detection means. To do.

  Further, the lifting load detecting means may detect the number of rotations when the lifting motor is driven with a certain input power.

  Further, when the lifting motor is driven with a certain input power and the rotational speed is smaller than a predetermined value, it is determined that the carriage is normally at a predetermined position, and the position is determined as the origin position of the carriage. It is desirable.

  The lifting load detecting means may detect the magnitude of input power when the lifting motor is driven at a certain rotational speed.

  Further, when the lifting motor is driven at a certain rotation speed and the magnitude of input power is larger than a predetermined value, it is determined that the carriage is normally at a predetermined position, and the position is determined as the origin position of the carriage. It is desirable.

  The lifting load detecting means may detect the magnitude of input power when the lifting motor is accelerated from a stopped state to a certain rotational speed.

  Further, when the lifting motor is accelerated from a stopped state to a certain number of revolutions, and the magnitude of input power is larger than a predetermined value, it is determined that the carriage is normally at a predetermined position, and the position is determined as the origin position of the carriage. It is desirable to do.

  The lifting load detection means detects a time required for the motor rotation speed to reach a certain value when the input power to the lifting motor is changed from a stopped state to a certain value. It may be a thing.

  Further, when the power input to the lifting motor is changed from a stopped state to a certain value, and the time required for the motor rotation speed to reach a certain value from the stopped state is larger than a predetermined value, the carriage is normally moved to a predetermined position. It is desirable to determine that the position is the origin position of the carriage.

  Further, it is preferable that the lift motor is continuously driven so that the recording head is set at a predetermined lift position even after the origin position of the carriage is determined.

  According to the present invention, the origin position of the carriage can be reliably determined.

The schematic diagram which looked at the inkjet recording device of this invention from the upper surface is shown. The schematic diagram which looked at the inkjet recording device of this invention from the left side is shown. FIG. 2 is a schematic view of the elevation of the recording head of the inkjet recording apparatus of the present invention as viewed from the left side of the recording apparatus. FIG. 2 is a schematic view of the recording apparatus when the carriage of the present invention is at the origin position as seen from above. The schematic diagram which looked at the 2nd raising / lowering mechanism of this invention from the recording device right side is shown. 4 is a graph illustrating the relationship between the number of rotations of the lifting motor and the amount of lifting of the recording head according to the present invention. The schematic structure of the control system of this apparatus is shown. The systematic diagram of the principal part in connection with this invention is shown. 1 shows a block diagram of a DSP of the present invention. An example of a structure of the DC brushless motor of this invention is shown. It is an operation | movement flowchart of 1st Example of this invention. It is an operation | movement flowchart of 2nd Example of this invention. It is an operation | movement flowchart of the 3rd Example of this invention. It is an operation | movement flowchart of the 4th Example of this invention.

Example 1
An ink jet recording apparatus according to an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are schematic schematic views of an ink jet recording apparatus according to the present invention. In the ink jet recording apparatus, a recording head 2 that discharges ink onto a recording medium 1 is mounted on a carriage 3. Then, as the carriage 3 is moved by the timing belt 5 along the guide rail 4 attached to the recording apparatus main body, the recording head 2 is scanned along the recording medium 1 while being moved onto the recording medium 1 by the recording head 2. Ink is ejected. Here, the timing belt 5 is connected to a pulley 7 installed on the rotation shaft of the carriage drive motor 6, and the rotational movement of the carriage drive motor 6 is converted into the linear movement of the timing belt 5. At the same time, printing is performed by sequentially transporting the recording medium 1 in the direction of the arrow in FIG. 2 by transporting means constituted by a pair of transporting rollers 8a and 8b. A platen 9 is provided at a position facing the recording head 2 as a support surface for supporting the recording medium 1 being conveyed.

  In recent years, there are various types of recording media depending on the purpose of printing, and there are a wide variety of thicknesses and characteristics. Therefore, in order to perform appropriate printing according to the thickness and characteristics of the recording medium, it is necessary to change the distance between the recording head and the platen according to the recording medium to be recorded. Here, the configuration of the mechanism for changing between the recording head and the platen in the present invention will be described with reference to FIGS. A first elevating mechanism 10 is mounted on the carriage 3 and includes a lift shaft 10a, a lift cam 10b, and a concave connecting member 10c. The recording head 2 is in contact with the surface of the lift cam 10b, and the center of the lift cam 10b is deviated from the center of the lift shaft 10a. The concave connecting member 10c is joined to one end of the lift shaft 10a, and the lift shaft 10a is installed in a state of being engaged with the carriage 3. By rotating the concave connecting member 10c, the lift shaft 10a and the lift cam 10b rotate, the height of the contact point between the lift cam 10b and the recording head 2 moves, and the recording head 2 moves up and down. On the other hand, a second elevating mechanism 12 is mounted on the frame 11 installed at the right end of the recording apparatus main body, and is composed of an elevating motor 12a, a connecting gear portion 12b, and a convex connecting member 12c. By driving the elevating motor 12a, the convex coupling member 12c is rotated via the coupling gear portion 12b.

  As shown in FIG. 4, when the carriage 3 reaches the right end position of the main body, the stopper portion 3a of the carriage 3 hits the frame 11, and the carriage 3 cannot move any more, and at the same time, the concave connection member 10c and the convex connection The member 12c is connected and fitted. When the lifting motor 12a is driven, the recording head 2 can be lifted by rotating the lift cam 10b via both connecting members.

  Here, the relationship between the rotation of the elevation motor 12a and the elevation amount of the recording head 2 and the elevation position setting method will be described with reference to FIGS. FIG. 5 is a schematic side view of the second lifting mechanism 12 as viewed from the right side in FIG. A lift sensor 12d, which is a transmissive photo interrupter, is provided in the frame, and a blocking plate 12e is provided in the connecting gear portion 12b. The light blocking / transmitting state of the lift sensor 12d by the blocking plate 12e is switched depending on the rotational position of the elevating motor 12a. FIG. 6 shows an example of a relationship graph between the number of rotations of the lifting motor 12a and the recording head lifting amount. For example, when the elevation height f is set, the elevation motor 12a is rotated to detect when the lift sensor 12d is switched from light shielding to transmission by the blocking plate 12e. Since the number of rotations of the lifting motor 12a at the time of detection is 700, the desired lifting position is set by rotating the lifting motor 12a up to the number of rotations 1300 of the lifting height f, that is, the 600-speed lifting motor 12a.

  FIG. 7 shows a schematic configuration of the control system of this apparatus. Reference numeral 13 denotes a recording device. Reference numeral 14 denotes a recording device control unit that controls each device in the recording device. A power supply 15 supplies power to each device in the recording apparatus. Reference numeral 16 denotes sensors for detecting the status of each unit in the recording apparatus. A motor control unit 17 controls the motors according to an instruction from the recording device control unit. Reference numeral 18 denotes motors which are power sources of the respective apparatuses in the recording apparatus. A display unit 19 notifies the user of the operation status of the recording apparatus. A communication controller 20 performs communication between the recording apparatus and the host computer. A host computer 21 transfers data to be printed to the recording device.

  FIG. 8 shows a system diagram of main parts related to the present invention. Reference numeral 22 denotes a DSP, and 23a and 23b denote drivers for controlling power to the carriage drive motor 6 and the lifting motor 12a, respectively. The DSP compares the speed signal from the recording device control unit with the output of the speed detection means by comparing the speed signal from the recording device control unit with the phase switching control by the position signal from the motor, the motor start and stop control by the control signal from the recording device control unit Speed control.

  A block diagram of the DSP is shown in FIG. 24 is a program controller, 25a is an ALU that performs addition / subtraction and logical operations, 25b is a MAC that performs product-sum operations, 26 is a data memory, 27 is a program memory, 28 is a data memory bus, 29 is a program memory bus, and 30 is A serial port, 31 is a timer, and 32 is an I / O port. As described above, the memory is made independent for data and the program, the bus is separated into the data bus and the program bus, and a MAC for performing multiplication and addition in one machine cycle enables high-speed computation.

  In this embodiment, a DC brushless motor is used for the carriage drive motor 6 and the lifting motor 12a. FIG. 10 shows an example of the configuration of the DC brushless motor of the present invention. The DC brushless motor has a three-phase star-connected coil 33 and a rotor 34 of U, V, and W. Three Hall elements 35 for detecting the magnetic poles of the rotor are provided as rotor position detecting means, and their outputs are connected to the DSP. Further, it has a rotational speed detecting means comprising a magnetic pattern 36 and a magnetic sensor 37 provided on the outer periphery of the rotor, and its output is connected to the DSP.

  Reference numeral 23 denotes a driver for driving the DC brushless motor, which includes three high-side transistors 38 and three low-side transistors 39, which are connected to U, V, and W of the coil 33, respectively. Reference numeral 40 denotes a current detection resistor that converts a motor drive current into a voltage. The generated voltage is taken into the D / A port of the DSP.

  The DSP specifies the position of the rotor based on the rotor position signals HU to W generated by the hall elements, and generates a phase switching signal. The phase switching signals UU to W and LU to W control the on / off of each transistor of the driver, sequentially switch the phases to be excited, and rotate the rotor. Furthermore, the DSP compares the rotation speed target value with the rotation speed information, and generates and outputs a PWM signal.

  With reference to FIG. 11, an explanation will be given of an example of an operation flowchart from the time when the carriage 3 is waiting to the time when the carriage 3 receives a print job to the origin position setting and printing. The first elevating mechanism 10 and the second elevating mechanism 12 are detected by opening the elevating motor 12a by open loop control and driving the motor with a constant input power and detecting the magnitude of the motor load torque based on the motor rotation speed at that time. Detects connection fitting.

  When the recording device 13 receives a print job via the communication controller 20 in response to a command from the host computer 21 (S1), the motor control unit 17 sets the carriage drive motor 6 to move the carriage 3 from the standby position to the right end side of the main body. Driving is started (S2). At this time, in order to suppress an impact when the carriage 3 is abutted against the frame 11, the PWM value is normally driven to be less than 10%. Thereafter, when the stopper portion 3a of the carriage 3 comes into contact with the frame 11, the PWM value increases in order to keep the motor rotating. Therefore, by detecting whether the PWM value exceeds the set value and for the set time, the abutment of the carriage 3 on the frame is detected (S3).

  Here, in order to reliably detect an increase in the PWM value, the set value is set to be equal to or higher than the PWM value during normal driving of the carriage 3, for example, about 20%, and the set time is set to about 0.2 seconds in advance.

  Next, after the detection in step 3, the motor control unit 17 sets the PWM value so as to drive the elevating motor 12a with a constant input power (S4). Next, a time measurement counter is set (S5). This count value is set to a time sufficient for the motor rotation speed to reach an equilibrium state. Further, the driving of the elevating motor 12a is started by the PWM value (S6), and the counter is subtracted at regular intervals (S7). When the counter value reaches 0 (S8), the motor speed is measured (S9). After the measurement, the detected motor rotation speed is compared with the reference rotation speed (S10), and the connection state of the first lifting mechanism 10 and the second lifting mechanism 12 is determined.

  Here, the reference motor rotational speed is smaller than the rotational speed when only the second lifting mechanism 12 is rotated in order to correctly determine the connected state, and is larger than the rotational speed when the first lifting mechanism is connected. It is set in advance to be a value.

  If the detected number of rotations is greater than the reference number of rotations, the load torque is small, and it is determined that the connection is defective, that is, the main body is not at the right end position, and the rotation of the elevating motor 12a is stopped and an error is returned (S11). If the detected number of rotations is smaller than the reference number of rotations, it is determined that the load torque is large and that the connection is sufficient, that is, that the main body is at the right end position, and the origin is set (S12).

  After completion of the determination, the lifting motor 12a continues to be driven so as to be between the appropriate recording head and the platen based on the information of the recording medium 1 by the print job, and when the lift sensor is detected to be blocked and transmitted (S13), the predetermined rotation Rotate by the number to set the elevation position of the predetermined recording head 2 (S14). Thereafter, the printing operation, that is, the reciprocating operation of the carriage 3 is started (S15).

  In the above embodiment, the load torque of the elevating motor is detected by the motor rotation speed, but this method has a detection accuracy when using a motor having a characteristic with a large gradient of the curve indicating the motor rotation speed-torque characteristic. It is particularly effective because it increases.

(Example 2)
A second embodiment of the present invention will be described. Since the recording apparatus configuration of this apparatus and the schematic configuration of the control system are the same as those in the first embodiment, description thereof will be omitted.

  The first elevating mechanism 10 and the second elevating mechanism 12 are connected by detecting the magnitude of the load torque based on the magnitude of the PWM value when the elevating motor 12a is controlled in a closed loop and driven at a constant rotational speed. Detects mating.

  FIG. 12 shows an operation flowchart according to the second embodiment of the present invention from when the carriage 3 is in a standby state until a print job is received, the origin position is set, and printing is performed. Steps 1 to 3 are the same as those in the first embodiment, and a description thereof will be omitted.

  After the detection in step 3, the motor control unit 17 sets the final target rotational speed of the lifting motor 12a (S4). Next, the driving of the elevating motor 12a is started (S5), the motor speed is detected (S6), and the motor is controlled to rotate at the final target speed. When the motor rotation speed reaches the final target rotation speed (S7), the PWM value is stored at that time (S8). After the PWM value storage is completed, the stored PWM value is compared with the reference PWM value (S9), and the connection state of the first lifting mechanism 10 and the second lifting mechanism 12 is determined.

  Here, the reference PWM value is larger than the PWM value when only the second lifting mechanism 12 is rotated in order to correctly determine the connected state, and smaller than the PWM value when connected to the first lifting mechanism. Is set in advance so that

  If the stored PWM value is smaller than the reference PWM value, it is determined that the load torque is small, it is determined that the connection is defective, i.e., not at the right end position of the main body, and the rotation of the lifting motor 12a is stopped and an error is returned (S10). If the stored PWM value is larger than the reference PWM value, the load torque is large, and it is determined that the connection is sufficient, that is, the right end position of the main body, and the origin is set (S11). After completion of the determination, the lifting motor 12a continues to be driven so as to be between the appropriate recording head and platen based on the information of the recording medium 1 by the print job, and when the lift sensor is cut off and transmitted (S12), predetermined rotation is performed. Rotate by a number to set the elevation position of the predetermined recording head 2 (S13). Thereafter, the printing operation, that is, the reciprocating operation of the carriage 3 is started (S14).

  In this example, the detection is performed using the PWM value. However, the detection may be performed using the drive current instead of the PWM value.

  In the above embodiment, the load torque of the lifting motor is detected by the PWM value, but this method increases the detection accuracy when using a motor having a characteristic with a large gradient of the curve indicating the current-torque characteristic of the motor. It is particularly effective.

(Example 3)
A third embodiment of the present invention will be described. Since the recording apparatus configuration of this apparatus and the schematic configuration of the control system are the same as those in the first embodiment, description thereof will be omitted.

  When the elevating motor 12a is accelerated from a certain speed to a certain speed, the connection fitting of the first elevating mechanism 10 and the second elevating mechanism 12 is detected by detecting the load torque from the magnitude of the PWM value.

  FIG. 13 shows an operation flowchart according to the third embodiment of the present invention from when the carriage 3 is in a standby state until a print job is received, the origin position is set, and printing is performed. Steps 1 to 3 are the same as those in the first embodiment, and a description thereof will be omitted.

  After the detection in step 3, the motor control unit 17 sets the final target rotational speed of the lifting motor 12a (S4). Next, driving of the elevating motor 12a is started (S5), and the motor is accelerated from the rotational speed of 0 rpm to the final target rotational speed. While the motor is accelerating, the PWM value is detected at regular intervals, and the PWM value is added (S6). When the motor reaches the final target rotational speed (S7), the detection and addition processing of the PWM value is stopped, the total sum of the calculated PWM values is compared with the reference value (S8), and the first elevating mechanism 10 and the first The connection state of the two lifting mechanisms 12 is determined.

  Here, the reference sum of PWM values is larger than the sum of PWM values when only the second lifting mechanism 12 is rotated in order to correctly determine the connected state, and the PWM when connected to the first lifting mechanism. It is set in advance so that the value is smaller than the sum of the values.

  If the sum of the calculated PWM values is smaller than the reference value, the load torque is small, and it is determined that the connection is defective, i.e., not at the right end position of the main body, and the rotation of the lifting motor 12a is stopped and an error is returned (S9). If the sum of the calculated PWM values is larger than the reference value, the load torque is large, and it is determined that the connection is sufficient, that is, the right end position of the main body, and the origin is set (S10). After the determination, based on the information on the recording medium 1 by the print job, the elevating motor 12a continues to drive so as to be between the appropriate recording head and platen, and when the lift sensor is cut off and transmitted (S11), the predetermined rotation Rotate by the number to set the elevation position of the predetermined recording head 2 (S12). Thereafter, the printing operation, that is, the reciprocating operation of the carriage 3 is started (S13).

  The detection method based on the sum of PWM values in the above embodiment is particularly effective because the detection accuracy increases when a motor having a characteristic with a large gradient of the curve indicating the current-torque characteristic of the motor is used. Furthermore, the PWM fluctuation value at the time of acceleration of the motor can be used, and it is not always necessary to rotate the motor until it reaches the constant speed rotation state as in the third embodiment, and the detection time can be shortened.

Example 4
A fourth embodiment of the present invention will be described. Since the recording apparatus configuration of this apparatus and the schematic configuration of the control system are the same as those in the first embodiment, description thereof will be omitted.

  When the input power to the lifting motor 12a is changed from 0 to a certain value, the first lifting mechanism 10 is detected by detecting the load torque from the time required until the rotational speed of the motor changes from 0 to a certain value. And the connection fitting of the second elevating mechanism 12 is detected.

  FIG. 14 is an operation flowchart according to the fourth embodiment of the present invention from when the carriage 3 is waiting until the print job is received, the origin position is set, and printing is performed. Steps 1 to 3 are the same as those in the first embodiment, and a description thereof will be omitted.

  After the detection in step 3, the motor control unit 17 sets the PWM value of the lifting motor 12a, the target rotational speed of the motor, and the counter (S4). Further, the driving of the elevating motor 12a is started based on the PWM value (S5), the counter is added at regular intervals (S6), and the motor speed is detected (S7). When the motor speed reaches the target rotational speed (S8), the value of the time measurement counter is stored (S9). After the storage is completed, the stored counter value is compared with the reference value (S10), and the connection state of the first lifting mechanism 10 and the second lifting mechanism 12 is determined.

  Here, the reference counter value is larger than the counter value when only the second elevating mechanism 12 is rotated in order to correctly determine the connection state, and smaller than the rotation number when it is connected to the first elevating mechanism. Is set in advance so that

  If the stored counter value is smaller than the reference value, the load torque is small, and it is determined that the connection is defective, that is, it is not at the right end position of the main body, and the rotation of the elevating motor 12a is stopped and an error is returned (S11). If the stored counter value is larger than the reference value, the load torque is large, and it is determined that the connection is sufficient, that is, the right end position of the main body, and the origin is set (S12). After completion of the determination, the lifting motor 12a continues to be driven so as to be between the appropriate recording head and the platen based on the information of the recording medium 1 by the print job, and when the lift sensor is detected to be blocked and transmitted (S13), the predetermined rotation Rotate by the number to set the elevation position of the predetermined recording head 2 (S14). Thereafter, the printing operation, that is, the reciprocating operation of the carriage 3 is started (S15).

  The detection method in the above embodiment is particularly effective because the detection accuracy increases when a motor having a characteristic with a large gradient of the curve indicating the rotation speed-torque characteristic of the motor is used. Furthermore, it is not necessary to rotate the motor until it reaches the constant speed rotation state as in the first embodiment, and the detection time can be shortened.

  As described in the first to fourth embodiments, since the origin position of the carriage is detected by setting both the abutment of the carriage to the mechanical stopper and the torque detection of the lifting motor, the origin position is surely determined. Detection can be performed.

  Furthermore, the present invention has the effect of reliably detecting the elevation of the recording head. That is, in the process of setting the print head to a predetermined lift position, the print head lift is set only by detecting both the torque of the lift motor and the lift sensor blocking-transmission, and the process proceeds to the next carriage movement. . This ensures that, for example, the recording head is not raised sufficiently in a state where a thick recording medium is set on the platen, the carriage moves, and the recording head is damaged by interference with the recording medium. It has the effect of preventing.

DESCRIPTION OF SYMBOLS 1 Recording medium 2 Recording head 3 Carriage 4 Guide rail 5 Timing belt 6 Carriage drive motor 7 Pulley 8 Conveying roller pair 9 Platen 10 1st raising / lowering mechanism 11 Frame 12 2nd raising / lowering mechanism 13 Recording apparatus 14 Recording apparatus control part 15 Power supply 16 Sensors 17 Motor Control Unit 18 Motors 19 Display Unit 20 Communication Controller 21 Host Computer 22 DSP
23 Driver 24 Program Controller 25 Arithmetic Unit 26 Data Memory 27 Program Memory 28 Data Memory Bus 29 Program Memory Bus 30 Serial Port 31 Timer 32 I / O Port 33 Coil 34 Rotor 35 Hall Element 36 Magnetic Pattern 37 Magnetic Sensor 38 High Side Transistor 39 Low side transistor 40 Current detection resistor

Claims (10)

  A carriage mounted with a recording head for forming an image on a recording medium, reciprocally moved by a drive motor, carriage control means for controlling the reciprocating drive of the carriage, and a carriage load for detecting the load of the carriage drive motor The detecting means engages with the first recording head lifting part mounted on the carriage and the second recording head lifting part mounted on the frame of the recording apparatus when the carriage is in a predetermined position, Elevating means for elevating and lowering the recording head by an elevating motor, elevating control means for controlling elevating drive of the recording head, and elevating load detecting means for detecting a load of the elevating motor, the carriage load detection And an origin position of the carriage is determined on the basis of detection results of the means and the lifting load detection means. Jet recording device.   2. The ink jet recording apparatus according to claim 1, wherein the lifting load detecting unit detects the number of rotations when the lifting motor is driven with a certain input power.   When the elevating motor is driven with a certain input power and the rotational speed is smaller than a predetermined value, it is determined that the carriage is normally at a predetermined position, and the position is determined as the origin position of the carriage. The ink jet recording apparatus according to claim 2.   The recording apparatus according to claim 1, wherein the lifting load detecting unit detects a magnitude of input power when the lifting motor is driven at a certain rotation speed.   When the lifting motor is driven at a certain number of revolutions, and the magnitude of input power is greater than a predetermined value, it is determined that the carriage is normally at a predetermined position, and the position is determined as the origin position of the carriage. The inkjet recording apparatus according to claim 4.   2. The ink jet recording apparatus according to claim 1, wherein the lifting load detecting unit detects a magnitude of input power when the lifting motor is accelerated from a stopped state to a certain number of rotations.   When the lifting motor is accelerated from a stopped state to a certain number of revolutions and the magnitude of input power is larger than a predetermined value, it is determined that the carriage is normally at a predetermined position, and the position is determined as the origin position of the carriage. The inkjet recording apparatus according to claim 4.   The lifting load detecting means detects the time required for the motor rotation speed to reach a certain value when the input power to the lifting motor is changed from a stopped state to a certain value. The inkjet recording apparatus according to claim 1, wherein   When the electric power supplied to the elevating motor is changed from a stopped state to a certain value, and the time required for the motor rotation speed to reach a certain value from the stopped state is larger than a predetermined value, the carriage is normally moved to a predetermined position. 9. The ink jet recording apparatus according to claim 8, wherein the ink jet recording apparatus determines that the position is present and determines the position as an origin position of the carriage.   10. The ink jet recording apparatus according to claim 1, wherein after the origin position of the carriage is determined, the lifting motor is continuously driven so that the recording head is set at a predetermined lifting position.