JP4484682B2 - Recording apparatus and carriage speed prediction method - Google Patents

Description

  The present invention relates to a recording apparatus and a carriage speed prediction method, and more particularly to a recording apparatus and a carriage speed prediction method that perform serial recording, for example, with an inkjet recording head mounted on a carriage.

  In a conventional serial recording apparatus, a pulse motor has been used as a mechanical system drive source for ease of control. In this case, the stop at the target position can be controlled by the number of pulses applied to the motor, and the speed can be controlled by the pulse period. In order to reduce operating noise, the current flowing through the motor is made sinusoidal using a technique such as microstepping.

  In recent years, a reduction in operating noise has been demanded, and a shift from a pulse motor to a DC motor is progressing as a drive source. However, when a DC motor is used, digital control as in the case of using a pulse motor cannot be performed, and analog control must be performed.

  For example, in the drive control of a carriage mounted with a recording head, a scale slit provided along the carriage moving direction is read by an encoder mounted on the carriage, and the carriage is controlled based on the encoder signal obtained as a result. The position and speed are obtained, and the voltage applied to the DC motor to be applied is determined while comparing with the target speed and position.

  Now, the above-described scale is provided with slits at regular intervals, and the position and speed of the carriage can be known from the number of slit passages and the number of slit passages per unit time. When detecting the position and speed, use one of the two encoder signals obtained and know the direction of carriage movement at the level of the other phase. Yes. Phase detection uses the edge on one side of the phase.

  However, in such a method, the movement time from one slit to the next slit becomes longer at a low speed just before the carriage stops, and the frequency of updating position information and speed information decreases, so the accuracy of position / speed detection decreases. To do.

  As countermeasures against this problem, the following techniques are conventionally known.

That is, by using both rising and falling edges of both phases of the encoder signal, the edge intervals that occur one after another are successively recorded, and the carriage speed is obtained from the sum of the data closest to the present and the past three data. The sum of the data closest to the present and the past three data corresponds to one period of the encoder in the conventional method. In this way, information is updated every ¼ of the time required for normal detection, so that an improvement in accuracy can be expected (see, for example, Patent Document 1).
JP 2001-219613 A

  However, the conventional example still has the following problems.

  That is, the speed information obtained at a certain point in time is obtained based on the moving time between the slit through which the carriage (that is, the encoder) passes immediately before the information is obtained, and this data is obtained. When the control is determined using, after a time of 1/4 or more of the encoder cycle has elapsed, the detection error becomes large at a low speed of the carriage, particularly during acceleration / deceleration of the carriage.

  The present invention has been made in view of the above problems, and an object thereof is to provide a recording apparatus and a carriage speed prediction method capable of predicting the carriage speed more accurately even when the carriage movement speed is low. .

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, a recording apparatus that performs recording on a recording medium by reciprocating a carriage having a recording head driven by a driving force of a carriage motor, provided along the moving direction of the carriage, and provided with slits at predetermined equal intervals. A scale that is mounted on the carriage and moves together with the carriage and reads a slit of the scale to detect the position of the carriage; and a rise time of a detection signal obtained immediately after the encoder reads the slit; Prediction means for predicting the speed of the carriage from at least one of the falling times.

  The slits are preferably provided in two rows in the carriage direction, and the two rows of slits are preferably shifted with respect to each other so that the encoder generates two detection signals having a phase difference of 90 degrees.

  The carriage motor is preferably a DC motor.

  Further, it is desirable that the prediction means predicts the carriage speed four times per one cycle of the detection signal from the rise time and the fall time of each of the two detection signals having a phase difference of 90 degrees.

  Still further, it is desirable to include control means for controlling the driving of the carriage motor based on the predicted speed predicted by the prediction means and the carriage position detected by the encoder.

  The prediction means compares the detection signal with a first threshold value, and compares the detection signal with a second threshold value greater than the first threshold value. Means, a determination means for determining the rise time and the fall time based on the comparison results by the first and second comparison means, and the rise determined from the comparison result by the first comparison means. It is desirable to provide discrimination means for discriminating time and fall time.

  Further, the predicting means includes a table storing a reference value for comparing the rising time and the falling time, and can predict the carriage moving speed from a comparison between the reference value of the table and the rising time or the falling time. desirable.

  The recording head may be an ink jet recording head that performs recording by discharging ink, and the ink jet recording head uses electric energy to generate thermal energy to be applied to the ink in order to discharge ink using thermal energy. More preferably, a converter is provided.

  According to another aspect of the invention, there is provided a carriage drive control method used in a recording apparatus for performing recording on a recording medium by reciprocating a carriage having a recording head by a driving force of a carriage motor. A detection step of detecting the position of the carriage by reading the slit of the scale using an encoder that moves together with the carriage from a scale provided with slits at predetermined equal intervals, and the encoder reads the slit. And a prediction step of predicting the speed of the carriage from at least one of the rising time and the falling time of the detection signal obtained immediately thereafter.

  Therefore, according to the present invention, since the carriage speed is predicted from at least one of the rise time and fall time of the detection signal obtained immediately after the encoder reads the slit, the encoder closest to the current time of the carriage There is an effect that it is possible to predict the speed based on the detection signal from Therefore, more accurate speed prediction is realized even during acceleration / deceleration at a low speed of the carriage.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings.

  In this specification, “recording” (sometimes referred to as “printing”) is not only for forming significant information such as characters and figures, but also for human beings visually perceived regardless of significance. Regardless of whether or not it has been manifested, it also represents a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Furthermore, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly in the same way as the definition of “recording (printing)” above. It represents a liquid that can be used for forming a pattern or the like, processing a recording medium, or processing an ink (for example, solidification or insolubilization of a colorant in ink applied to the recording medium).

  Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port or a liquid channel communicating with the ejection port and an element that generates energy used for ink ejection.

<Description of Inkjet Recording Apparatus (FIG. 1)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus which is a typical embodiment of the present invention.

  As shown in FIG. 1, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) transmits a driving force generated by a carriage motor M1 to a carriage 2 on which a recording head 3 that performs recording by discharging ink according to an ink jet system is mounted. 4, the carriage 2 is reciprocated in the direction of arrow A, and for example, a recording medium P such as recording paper is fed through a paper feeding mechanism 5 and conveyed to a recording position. Recording is performed by ejecting ink onto the recording medium P.

  Further, in order to maintain the state of the recording head 3 satisfactorily, the carriage 2 is moved to the position of the recovery device 10 and the ejection recovery process of the recording head 3 is intermittently performed.

  In addition to mounting the recording head 3 on the carriage 2 of the recording apparatus 1, an ink cartridge 6 for storing ink to be supplied to the recording head 3 is mounted. The ink cartridge 6 is detachable from the carriage 2.

  The recording apparatus shown in FIG. 1 is capable of color recording. For this reason, the carriage 2 contains four inks containing magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively. A cartridge is installed. These four ink cartridges are detachable independently.

  Now, the carriage 2 and the recording head 3 can achieve and maintain a required electrical connection by properly contacting the joint surfaces of both members. The recording head 3 applies energy according to a recording signal to selectively eject ink from a plurality of ejection ports for recording. In particular, the recording head 3 of this embodiment employs an ink jet system that ejects ink using thermal energy, and includes an electrothermal transducer to generate thermal energy, which is applied to the electrothermal transducer. Electric energy is converted into thermal energy, and ink is ejected from the ejection port by utilizing pressure changes caused by bubble growth and contraction caused by film boiling caused by applying the thermal energy to the ink. The electrothermal transducer is provided corresponding to each of the ejection ports, and ink is ejected from the corresponding ejection port by applying a pulse voltage to the corresponding electrothermal transducer in accordance with the recording signal.

  As shown in FIG. 1, the carriage 2 is connected to a part of the driving belt 7 of the transmission mechanism 4 that transmits the driving force of the carriage motor M <b> 1, and slides in the direction of arrow A along the guide shaft 13. It is guided and supported freely. Accordingly, the carriage 2 reciprocates along the guide shaft 13 by forward and reverse rotations of the carriage motor M1. A scale 8 is provided for indicating the absolute position of the carriage 2 along the direction of movement of the carriage 2 (the direction of arrow A). In this embodiment, the scale 8 uses a transparent PET film printed with black bars (slits) at a necessary pitch, one of which is fixed to the chassis 9 and the other is a leaf spring (not shown). It is supported. The carriage 2 is provided with an encoder (not shown) for reading the slits of the scale 8.

  The slits are composed of upper and lower two rows of slits along the carriage movement direction, and these two rows of slits generate encoder signals of phases (A phase, B phase) that are 90 degrees different from each other. Has been.

  Further, the recording apparatus is provided with a platen (not shown) facing the discharge port surface where the discharge port (not shown) of the recording head 3 is formed, and the recording head 3 is driven by the driving force of the carriage motor M1. Simultaneously with the reciprocating movement of the mounted carriage 2, recording is performed over the entire width of the recording medium P conveyed on the platen by giving a recording signal to the recording head 3 and discharging ink.

  Further, in FIG. 1, 14 is a conveyance roller driven by a conveyance motor M2 to convey the recording medium P, 15 is a pinch roller that abuts the recording medium P against the conveyance roller 14 by a spring (not shown), and 16 is a pinch. A pinch roller holder 17 that rotatably supports the roller 15 is a conveyance roller gear fixed to one end of the conveyance roller 14. Then, the transport roller 14 is driven by the rotation of the transport motor M2 transmitted to the transport roller gear 17 through an intermediate gear (not shown).

  Further, reference numeral 20 denotes a discharge roller for discharging the recording medium P on which an image is formed by the recording head 3 to the outside of the recording apparatus, and is driven by transmitting the rotation of the transport motor M2. . The discharge roller 20 abuts on a spur roller (not shown) that presses the recording medium P by a spring (not shown). Reference numeral 22 denotes a spur holder that rotatably supports the spur roller.

  Further, as shown in FIG. 1, the recording apparatus includes a desired position (for example, a home position) outside the range of reciprocating motion (outside the recording area) for the recording operation of the carriage 2 on which the recording head 3 is mounted. A recovery device 10 for recovering the ejection failure of the recording head 3 is disposed at a position corresponding to (1).

  The recovery device 10 includes a capping mechanism 11 for capping the ejection port surface of the recording head 3 and a wiping mechanism 12 for cleaning the ejection port surface of the recording head 3, and interlocks with the capping of the ejection port surface by the capping mechanism 11. Ink recovery such as forcibly discharging ink from the discharge port by suction means (suction pump or the like) in the recovery device, thereby removing ink or bubbles having increased viscosity in the ink flow path of the recording head 3 Process.

  Further, when the recording head 3 is not in operation or the like, the ejection port surface of the recording head 3 is capped by the capping mechanism 11 to protect the recording head 3 and to prevent ink evaporation and drying. On the other hand, the wiping mechanism 12 is disposed in the vicinity of the capping mechanism 11 and wipes ink droplets adhering to the ejection port surface of the recording head 3.

  The capping mechanism 11 and the wiping mechanism 12 can keep the ink ejection state of the recording head 3 normal.

  In this embodiment, a DC motor is employed as the carriage motor M1.

<Control Configuration of Inkjet Recording Apparatus (FIG. 2)>
FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 2, the controller 600 includes an MPU 601, a program corresponding to a control sequence to be described later, a required table, a ROM 602 that stores other fixed data, a carriage motor M1, a conveyance motor M2, and a recording. A special purpose integrated circuit (ASIC) 603 that generates a control signal for controlling the head 3, and a RAM 604, an MPU 601, an ASIC 603, and a RAM 604, which are provided with image data development areas and program execution areas, are connected to each other. A system bus 605 for transferring data, and an A / D converter 606 for inputting analog signals from the sensor group described below, A / D converting them, and supplying digital signals to the MPU 601 and the like.

  In FIG. 2, reference numeral 610 denotes a computer (or a reader for image reading, a digital camera, etc.) serving as a supply source of image data, and is collectively referred to as a host device. Image data, commands, status signals, and the like are transmitted and received between the host apparatus 610 and the recording apparatus 1 via an interface (I / F) 611.

  Further, reference numeral 620 denotes a switch group, which instructs activation of a power switch 621, a print switch 622 for instructing printing start, and a process (recovery process) for maintaining the ink ejection performance of the recording head 3 in a good state. For example, a recovery switch 623 for receiving a command input from the operator. Reference numeral 630 denotes a position sensor 631 such as a photocoupler for detecting the home position h, a temperature sensor 632 provided at an appropriate location of the recording apparatus for detecting the environmental temperature, and the like. It is a sensor group.

  Further, 640 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage 2 in the direction of arrow A, and 642 is a conveyance motor driver that drives a conveyance motor M2 for conveying the recording medium P.

  The ASIC 603 transfers drive data (DATA) of the printing element (ejection heater) to the printing head while directly accessing the storage area of the RAM 602 during printing scanning by the printing head 3.

  The encoder signal from the encoder 2 a mounted on the carriage 2 is transferred to the MPU 601 of the controller 600 through the position detection mechanism 641.

  FIG. 3 is a block diagram showing a detailed configuration of the position detection mechanism 641 and a control configuration of its peripheral portion.

  As shown in FIG. 3, the position detection mechanism 641 includes a tr and tf measuring unit 641a for measuring the rising time (tr) and the falling time (tf) of the encoder signal from the encoder 2a, and the carriage from the tr time and the tf time. A speed conversion unit 641c that converts to a speed and a position detection unit 641b that detects the carriage position by counting the number of slits of the scale 8 based on the encoder signal are included. The detected carriage speed and carriage position are output to the MPU 601.

  Here, the carriage speed / position detection according to this embodiment will be described in comparison with a conventional detection method.

  FIG. 4 is a signal time chart showing an outline of carriage speed / position detection. Here, FIG. 4A shows an outline of the conventional example, and FIG. 4B shows an outline of this embodiment.

  First, a conventional example will be described.

  FIG. 4A illustrates the A phase and B phase that are encoder output signals and the manner in which the speed information is updated. As can be seen from FIG. 4 (a), if the angle from the rise of the A phase to the next rise of the A phase is 360 degrees, the phase of the B phase signal is delayed by 90 degrees.

  Conventionally, the intervals of all the rising and falling transition points of both the A-phase and B-phase signals are measured, and the position / velocity information is obtained every quarter of one encoder cycle. It was. Regarding the speed information, the latest information and the information for the previous three consecutive times are combined to obtain information for one period of the encoder. And when the duty of the output signal of A phase or B phase differs, speed information was calculated | required by the optimal method as needed. The speed information obtained at a certain point in time is obtained based on information whose phase is 90 degrees before, that is, the movement time between the immediately preceding slit and the immediately preceding slit. The detection error may increase during acceleration / deceleration at low speed.

  Next, an outline of this embodiment will be described.

  FIG. 4 (b) also shows the A and B phases, which are encoder output signals, and how the speed information is updated. In the conventional example, the speed is predicted by measuring the time between the change points of each phase. In this embodiment, the speed is predicted from the rise time or fall time of the waveform at each change point. In this method, the speed information at a certain time is obtained from the information of the immediately preceding change point, and there is less time error than in the conventional example, so that it is effective for speed prediction when the carriage is accelerating / decelerating.

  Here, the outline of the configuration of the tr and tf measurement unit 641a according to this embodiment and the procedure for obtaining the rise time (tr) and fall time (tf) of the encoder signal will be described.

  FIG. 5 is a time chart of signals related to the calculation of the rise time (tr) and the fall time (tf) of the encoder signal.

  FIG. 5A shows an encoder waveform, and positions of 90% level and 10% level are shown as threshold values of H level and L level. FIG. 5B is a signal indicating whether the encoder waveform shown in FIG. 5A is higher than the H level or higher than the L level, and a signal indicating a section where the encoder signal is higher than the L level. A signal that is referred to as Level 10 and indicates a section that is higher than the H level is referred to as Level 90.

  In this embodiment, the rise time (tr) and fall time (tf) of the encoder signal are obtained by taking the exclusive OR of the two signals Level10 and Level90. Further, in this embodiment, by monitoring the signal Level 10 immediately before entering the rise time (tr) or fall time (tf) period, the period is the rise time (tr) period (tr period). It is determined whether there is a falling time (tf) period (tf period).

  FIG. 5C shows a state in which the time of the tr period or tf period is measured.

  Since the tr period and the tf period can be discriminated from the two signals (Level 10, Level 90) shown in FIG. 5B, the counter is operated only during that period, and when the period ends, the counter is stopped and the value at that time is latched To do. Accordingly, the counter output (counter) is a tr period and a tf period, and the result is output as a tr signal immediately after the tr period ends, and as a tf signal immediately after the tf period ends.

  FIG. 6 is a diagram showing an outline of a circuit used for measuring two signals (Level 10 and Level 90).

  FIG. 6 illustrates two comparators 671 and 672. The comparator 671 receives a threshold signal (Vref 10) of the signal Level 10, and the comparator 672 receives a threshold signal (Vref 90) of the signal Level 90. The encoder signal is input to both comparators. That is, when the encoder signal reaches Vref10, the control signal Level10 becomes active, and when it reaches Vref90, the control signal Level90 becomes active.

  Next, the operation of the carriage speed conversion unit 641c that calculates the carriage speed from the tr time and the tf time will be described.

  FIG. 7 is a signal time chart showing an outline of a procedure for determining the carriage speed from the tr period or the tf period.

  In this embodiment, a conversion table is used to determine the carriage speed.

  That is, at each conversion point of the A phase and B phase of the encoder signal, the obtained tr period or tf period is compared with a conversion table recorded in advance in a storage area such as a ROM and converted to a speed at any time. . In the example shown in FIG. 7, referring to the table stored in the ROM, if Tref0 ≦ tr <Tref1, the carriage speed (v) is determined as v = V0, and if Tref1 ≦ tr <Tref2, v = V1. If Tref2 ≦ tr <Tref3, then v = V2.

  The control is the same even if the conversion table is appropriately divided, such as for A phase, B phase, tr, and tf.

  In the example shown in FIG. 7, tr periods obtained from the A-phase encoder signal are expressed as tra1, tra2,... In time order, and tr periods obtained from the B-phase encoder signal are trb1, trb2,. The tf period obtained from the A phase encoder signal is expressed as tfa1, tfa2,..., And the tf period obtained from the B phase encoder signal is expressed as tfb1, tfb2,. .

  FIG. 7 shows a conventional example in which speed information is obtained based on respective rising times and falling edges of an encoder signal at a certain point in time and the moving times between the rising and falling edges of an encoder signal having a phase difference of 90 degrees. The travel times used in this method are indicated as Vra1, Vrb1, Vfa1, Vfb1, Vra2, Vrb2,.

  From these comparisons, it can be seen that in this embodiment, the carriage speed is obtained in real time as compared with the conventional one.

  FIG. 8 is a diagram showing the timing of carriage speed detection.

  In FIG. 8, Atr is a signal for detecting the rise of the A-phase encoder signal, Btr is a signal for detecting the rise of the B-phase encoder signal, Atf is a signal for detecting the fall of the A-phase encoder signal, and Btf is B These are signals for detecting the fall of the phase encoder signal, and the conversion point of each of the A and B phase encoder signals can be found from these signals.

  Therefore, in this embodiment, the carriage speed (Vexp) at that time can be obtained almost in real time at the conversion points of the A and B encoder signals, and new speed information is transferred to the MPU 101 at any time. As a result, the speed information can be obtained earlier by ¼ period of the encoder signal than in the prior art.

  FIG. 9 is a flowchart showing carriage drive control processing according to this embodiment.

  First, in step S702, the carriage position is detected from the encoder signal.

  In the next step S703, it is checked whether the carriage 2 has reached the target position. Here, if it is determined that the carriage 2 has already reached the target position, the process proceeds to step S710, the carriage 2 is stopped, and the series of controls is terminated. On the other hand, if it is determined that the carriage 2 has not reached the target position, the process proceeds to step S704.

  In step S704, the rise time (tr) or the fall time (tf) of the encoder signal is measured according to the method described above, and then the carriage is determined from the rise time (tr) or the fall time (tf) using the conversion table. Find the speed.

That is, in step S705, the variable (n) is initialized (n = 0), and in step S706, for example, it is determined to which time zone the rise time (tr) belongs (t _n). ≦ tr, tf <t n + 1 ). Here, if the condition (t _n ≦ tr, tf <t n + 1 ) is not satisfied, the process proceeds to step S709, where the value of the variable (n) is sequentially incremented (+1), and the position to which the table refers After that, the process determines the condition in step S706.

On the other hand, if the condition (t _n ≦ tr, tf <t n + 1 ) is satisfied, the process proceeds to step S707, and the speed information corresponding to the range (Vrefn) is set as the predicted speed (Vexp). Update. Further, in step S708, the motor driving value is determined and driven based on the predicted speed (Vexp) and the carriage position information obtained in step S702, and then the process returns to step S702.

  Therefore, according to the embodiment described above, since the speed can be predicted almost in real time from the change point of the encoder signal closest to the current point of the carriage, more accurate speed prediction can be performed even when the carriage is accelerating / decelerating. .

  Furthermore, in the above embodiments, the liquid droplets ejected from the recording head have been described as ink, and the liquid stored in the ink tank has been described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiment includes means (for example, an electrothermal converter or a laser beam) that generates thermal energy as energy used to perform ink ejection, particularly in the ink jet recording system, and the ink is generated by the thermal energy. By using a system that causes a change in the state of recording, it is possible to achieve higher recording density and higher definition.

  In the above embodiments, the serial scan type ink jet recording apparatus has been described as an example. However, the present invention is not limited to this, and the present invention is also effective for recording apparatuses employing other recording methods, for example, a thermal transfer recording method. Applicable to.

  In addition, even the serial scan type as in the above embodiment is mounted on the recording head fixed to the apparatus main body or the apparatus main body, and the electrical connection with the apparatus main body and the ink from the apparatus main body The present invention is also effective when an exchangeable cartridge type recording head that can be supplied is used.

  In addition, the ink jet recording apparatus according to the present invention may be used as an image output apparatus for information processing equipment such as a computer, a copying apparatus combined with a reader, or a facsimile apparatus having a transmission / reception function. It may be one taken.

1 is a perspective view showing a configuration of an ink jet recording apparatus that is a typical embodiment of the present invention. FIG. 2 is a block diagram illustrating a control configuration of the recording apparatus illustrated in FIG. 1. It is a block diagram which shows the detailed structure of the position detection mechanism 641, and the control structure of the peripheral part. It is a signal time chart which shows the outline of a carriage speed and position detection. It is a time chart of the signal related to calculation of the rise time (tr) and fall time (tf) of an encoder signal. It is a figure which shows the outline of the circuit used in order to measure two signals (Level10, Level90). It is a signal time chart which shows the outline of the procedure which determines a carriage speed from tr period or tf period. It is a figure which shows the timing of a carriage speed detection. It is a flowchart which shows a carriage drive control process.

Explanation of symbols

2 Carriage 2a Encoder 8 Scale 601 MPU
640 Carriage motor driver 641 Position measurement mechanism 641a tr, tf measurement unit 641b Position measurement unit 641c Speed conversion unit 671, 672 Comparator M1 Carriage motor

Claims (10)

A recording apparatus for recording on a recording medium by reciprocating a carriage mounted with a recording head by a driving force of a carriage motor,
A scale provided along the moving direction of the carriage and provided with slits at predetermined equal intervals;
An encoder that is mounted on the carriage and moves with the carriage, and reads a slit of the scale to detect the position of the carriage;
A recording apparatus comprising: a predicting unit that predicts the speed of the carriage from at least one of a rising time and a falling time of a detection signal obtained immediately after the encoder reads the slit. .   The slits are provided in two rows in the carriage direction, and the slits in the two rows are shifted with respect to each other so that the encoder generates two detection signals having a phase difference of 90 degrees. The recording apparatus according to 1.   The recording apparatus according to claim 1, wherein the carriage motor is a DC motor.   The prediction means predicts the carriage speed four times per cycle of the detection signal from the rise time and the fall time of each of the two detection signals different in phase by 90 degrees. 4. The recording device according to any one of 3.   5. The apparatus according to claim 1, further comprising a control unit that controls driving of the carriage motor based on a predicted speed predicted by the prediction unit and a carriage position detected by the encoder. Recording device. The prediction means includes
First comparison means for comparing the detection signal with a first threshold;
Second comparison means for comparing the detection signal with a second threshold value greater than the first threshold value;
Determining means for determining the rise time and the fall time based on a comparison result by each of the first and second comparison means;
6. The recording according to claim 1, further comprising a discriminating unit that discriminates the rising time and the falling time determined by the determining unit from the comparison result by the first comparing unit. apparatus. The prediction means has a table storing a reference value for comparing the rise time and fall time,
The recording apparatus according to claim 6, wherein the moving speed of the carriage is predicted from a comparison between a reference value of the table and the rise time or the fall time.   The recording apparatus according to claim 1, wherein the recording head is an ink jet recording head that performs recording by discharging ink. The recording apparatus according to claim 8, wherein the ink jet recording head includes an electrothermal transducer for generating thermal energy applied to the ink in order to eject the ink using thermal energy. . A carriage speed prediction method used in a recording apparatus for recording on a recording medium by reciprocating a carriage mounted with a recording head by a driving force of a carriage motor,
A detection step of detecting the position of the carriage by reading the slit of the scale from an encoder that moves along with the carriage from a scale provided along the moving direction of the carriage and provided with slits at predetermined equal intervals;
And a prediction step of predicting the speed of the carriage from at least one of a rising time and a falling time of a detection signal obtained immediately after the encoder reads the slit. Prediction method.

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