JP4876859B2 - Waveform generator, droplet discharge device, and waveform generation control method - Google Patents

Description

  The present invention relates to a waveform generator, a droplet discharge device, and a waveform generation control method.

  Conventionally, a voltage waveform composed of a trapezoidal wave or a triangular wave is applied to the piezoelectric actuator of an ink jet head having a pressure generation chamber filled with ink and a piezoelectric actuator, and the volume of the piezoelectric actuator and the pressure of the pressure generation chamber are reduced. Ink jet heads that eject ink droplets by changing them have been proposed.

  Then, as such a voltage waveform generator for an inkjet head, a digital drive waveform is generated by a digital signal from the waveform information read from the storage means, the generated digital drive waveform is modulated, the modulation output is demodulated, and the actual output is demodulated. There has been proposed an apparatus that generates an analog waveform similar to a drive waveform and supplies a voltage and current that can drive an inkjet head based on a demodulated output (see, for example, Patent Document 1).

  The apparatus disclosed in Patent Document 1 processes a single drive waveform, but an inkjet recording apparatus that generates and drives a plurality of waveforms by a plurality of waveform generation circuits is also known (for example, Patent Document 2). reference.). The inkjet recording apparatus includes a memory for each waveform generation circuit, and the waveform generation circuit reads waveform information from the corresponding memory and generates a drive waveform.

However, providing storage means for storing waveform information for each waveform generation circuit requires storage means as the number of waveform generation circuits increases, leading to an increase in cost. Therefore, it is conceivable to store all waveform information in one storage means, but simultaneous access to the storage means from a plurality of waveform generation circuits occurs, and a delay occurs in reading out the digital drive waveform from the storage means, As a result, a delay occurs in waveform generation. Access control can be performed by providing an arbiter, but the problem of waveform generation delay cannot be solved. In addition, the configuration is complicated.
JP 2003-237068 A JP 2005-035085 A

  The present invention has been made in view of the above-described facts, and an object of the present invention is to provide a waveform generator, a droplet discharge device, and a waveform generation control method capable of generating a waveform with a simple configuration without delay.

In order to achieve the above object, the waveform generator of the invention of claim 1 extracts all change points at which the slope, which is the amount of change in voltage per unit time, in a plurality of types of voltage waveforms generated simultaneously, Generating means for generating waveform information of a predetermined number of bits indicating a slope of a partial waveform when each of a plurality of types of voltage waveforms is divided at each of the extracted change points; Storage means for storing waveform information of each partial waveform in the same period of the generated plural types of voltage waveforms in a continuous storage area so that waveform information of each partial waveform in the same period can be read in a batch And a plurality of waveforms that are provided corresponding to each of the plurality of types of voltage waveforms and generate the corresponding voltage waveforms by accumulating the waveform information of the input partial waveforms for the time length of the partial waveforms. Raw unit, wherein each of the waveform information of the partial waveform of the same period from the memory means is read out at once, the data of the waveform information of the partial waveform of the read the same period, the advance from the first bit Control means for cutting out each predetermined number of bits and controlling each piece of the cut-out waveform information to be input to each of the corresponding waveform generation means of the plurality of waveform generation means at the same timing. It consists of

In the invention of claim 2, when the time length of the partial waveform corresponding to the waveform information has elapsed since the waveform information was read from the storage means and input to the plurality of waveform generation means, the control means The waveform information of the partial waveform in the next period is read in a batch , and the read waveform information data of each partial waveform in the same period is cut out from the first bit for each predetermined number of bits. Each of the plurality of waveform generating means is controlled to be input to each of the corresponding waveform generating means of the plurality of waveform generating means at the same timing . The waveform information can be cumulatively added until the next waveform information is input to generate a voltage waveform.

  In the invention of claim 3, time information indicating a time length of each of the partial waveforms is stored in the storage means, and the control means is configured to store the storage means based on the time information stored in the storage means. It is possible to control the reading of the waveform information from and the input of the waveform information to the waveform generating means.

  In the invention of claim 4, the generating means extracts all of the change points in a plurality of types of waveforms generated simultaneously, arranges the extracted change points in time series, and each of the plurality of types of voltage waveforms. It is determined whether or not the slope changes before and after each of the arranged change points, and the partial waveform in the period from the change point at which the slope is changed to the next change point of the change point is Generate waveform information that shows the slope after the change, and generate waveform information that shows the same slope as the previous period for the partial waveform from the change point where it was determined that the slope has not changed to the next change point. Can do.

  According to a fifth aspect of the present invention, there is provided a droplet discharge device according to any one of the first to fourth aspects, and a discharge unit that discharges droplets based on a voltage waveform generated by the waveform generation device. And.

According to a sixth aspect of the present invention, there is provided a waveform generation control method comprising: extracting all change points at which a slope, which is a change amount of voltage per unit time, in a plurality of types of voltage waveforms generated simultaneously; Generating waveform information of a predetermined number of bits indicating a slope of a partial waveform when each of the waveforms is divided at each extracted change point; and each portion of the plurality of types of voltage waveforms in the same period Storing the waveform information of each partial waveform in the same period of the plurality of types of generated voltage waveforms in a continuous storage area of the storage means so that the waveform information of the waveforms can be read collectively; read collectively each of waveform information of partial waveforms of the same period from the means, the data of the waveform information of the partial waveform of the read-out the same period, the predetermined from the first bit Cut for each number of bits, the plurality of types of each provided corresponding voltage waveform, a plurality of waveforms for generating a voltage waveform by accumulating time length of the waveform information of the input portion waveform partial waveform Inputting each of the cut-out waveform information at the same timing to each of the corresponding waveform generation means of the generation means.

  As described above, according to the first and sixth aspects of the invention, waveform generation can be performed with a simple configuration and without delay. Further, only one storage means is required for a plurality of waveform generation means, and control lines and address lines can be made common, thereby suppressing an increase in the amount of hardware.

  According to invention of Claim 2 and 3, a voltage waveform can be produced | generated easily.

  According to invention of Claim 4, the waveform information of a partial waveform can be produced | generated easily.

  According to the fifth aspect of the present invention, waveform generation can be performed with a simple configuration without delay. Accordingly, it is possible to discharge droplets without delay. Further, only one storage means is required for a plurality of waveform generation means, and control lines and address lines can be made common, thereby suppressing an increase in the amount of hardware.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the waveform generation device 10 of the present exemplary embodiment is provided in a droplet discharge device 100.

  The droplet discharge device 100 is provided with a transport path 80 for transporting the paper stored in the paper feed tray 86 to the paper discharge tray 88. The conveyance path 80 is formed by a plurality of roller pairs 82, a drive roller 84, and the like, and supplies sheets one by one from the sheet feed tray 86 and finally discharges them to the sheet discharge tray 88.

  In the middle of the conveyance path 80, it is connected to the waveform generation device 10 and is composed of a plurality of recording heads 26 for each color of cyan (C), magenta (M), yellow (Y), and black (K). The recording head array 126 is arranged along the paper conveyance direction, and is controlled as described later to eject ink and form an image on the paper. As a recording head, a thermal system, a piezoelectric system, or the like can be applied. Here, a piezoelectric system is used.

  The piezoelectric recording head 26 has a pressure generating chamber filled with ink and a piezoelectric element. When a voltage waveform is applied to the piezoelectric element, the volume of the piezoelectric element changes and the pressure in the pressure generating chamber changes, so that ink droplets can be ejected from the nozzle communicating with the pressure generating chamber. Since the voltage waveform applied to the piezoelectric element is a waveform for driving the recording head 26, it is hereinafter referred to as a drive waveform.

  Each color recording head 26 is connected to ink tanks 90C, 90M, 90Y, and 90K that store ink of each color via piping (not shown), and ink of each color is supplied. Various known inks can be used as the ink. For example, water-based ink, oil-based ink, solvent-based ink, and the like.

  A paper detection sensor 92 is provided in the vicinity of the recording head array 126. When the paper detection sensor 92 detects the leading edge of the paper, ejection of ink droplets by the recording head array 126 is started. In addition, a pulse encoder 85 is provided immediately below the recording head array 126. The rotation timing of the roller pair 82 and the like in the vicinity of the recording head array 126 is detected. A clock signal for controlling is generated.

  A CPU 12 that controls the entire droplet discharge device 100 is connected to the waveform generation device 10. The CPU 12 executes a program stored in a ROM (not shown) or the like, and outputs a control signal for generating a drive waveform for driving the recording head 26 based on data stored in the ROM or the like to the waveform generation device 10. Perform the printing process.

  The waveform generation device 10 generates a drive waveform for driving the recording head 26 in accordance with a control signal from the CPU 12 and outputs it to the recording head 26. The waveform generation device 10 can generate a plurality of types of drive waveforms, and the amount of ink droplets to be ejected is adjusted according to the drive waveform used.

  FIG. 2 is a configuration diagram of the waveform generation apparatus 10.

  The waveform generation device 10 includes a waveform data generation unit 14, a waveform data adjustment unit 16, a waveform data storage unit 18, a control unit 20, a plurality of waveform generation units 22, and a waveform selection unit 24.

  The waveform data generation unit 14 generates waveform data based on a control signal from the CPU 12. The control signal includes information for specifying the shape of the drive waveform that drives the recording head 26. From this information, the waveform data generation unit 14 extracts, for each drive waveform, a change point at which the slope, which is the amount of change in voltage per unit time, and when the drive waveform is divided at each extracted change point. Waveform data indicating the slope of the partial waveform is generated. Further, waveform data indicating the time length of the partial waveform at this time is also generated. The waveform data generation unit 14 generates waveform data indicating the slope of each partial waveform and waveform data indicating the time length of the partial waveform for each of a plurality of types of drive waveforms that are simultaneously generated by the plurality of waveform generation units 22.

  The waveform data adjustment unit 16 adjusts the waveform data generated by the waveform data generation unit 14. Here, based on the waveform data generated by the waveform data generation unit 14, all of the extracted change points are arranged in time series in a plurality of types of drive waveforms generated simultaneously, and each of the plurality of types of drive waveforms is The waveform data indicating the gradient of the partial waveform when divided at all the change points is generated. In addition, waveform data indicating the time length of each partial waveform is also generated. As a result, it is possible to generate waveform data when a plurality of types of drive waveforms are divided at a common change point among the drive waveforms, and it is possible to share the waveform data indicating the time length.

  The waveform data storage unit 18 stores the waveform data adjusted by the waveform data adjustment unit 16.

  The control unit 20 sends a waveform data read signal and address information to the waveform data storage unit 18. As a result, the waveform data is read from the waveform data storage unit 18 and is output to the digital calculation unit 30 (described later) and the control unit 20 of the plurality of waveform generation units 22.

  Each of the plurality of waveform generators 22 has the same configuration, a digital operation unit 30 that generates a digital drive waveform by accumulating waveform data, and a D / A converter 32 that converts the digital drive waveform into an analog drive waveform. , And a power amplifying unit 34 that amplifies the converted analog drive waveform so as to obtain power necessary for driving the head.

  The waveform generator 22 selects a desired drive waveform from the drive waveforms generated by the waveform generators 22 and is connected to the waveform selector 24 that outputs to the recording head 26 as an appropriate liquid discharge unit that discharges ink. Has been.

  In the present embodiment, in order to simplify the description, the case where there are three waveform generators 22 will be described as an example.

  FIG. 3 is a diagram illustrating the configuration of the waveform data storage unit 18 and the control unit 20.

  The control unit 20 includes an addition number counter 40 and a control signal generation unit 42.

  When the waveform data (number of additions) indicating the time length output from the waveform data storage unit 18 is input to the addition number counter 40 via the data line 44, the waveform data (number of additions) is down-counted.

  The control signal generation unit 42 generates a read signal and address information for reading the waveform data from the waveform data storage unit 18 based on the count value of the addition counter 40. The generated read signal is output to the waveform data storage unit 18 via the control line 46, and the address information is output to the waveform data storage unit 18 via the address line 48. For example, when the count value of the addition counter 40 becomes 1, the address is incremented and the read signal is validated.

  The waveform data storage unit 18 includes a storage unit 36 and a selector 38.

  The storage unit 36 is a storage area that actually stores data, and stores the waveform data adjusted by the waveform data adjustment unit 16.

  The selector 38 is connected to the digital calculation unit 30 of each waveform generation unit 22 and the addition number counter 40 of the control unit 20 via a data line 44. The selector 38 is connected to the control signal generator 42 of the controller 20 via the control line 46 and the address line 48. The selector 38 reads the waveform data stored in the storage unit 36 in accordance with the read signal and the address information input from the control signal generation unit 42 via the control line 46 and the address line 48, and the read waveform data is data The data is output to the digital arithmetic unit 30 and the addition counter 40 of the control unit 20 via the line 44.

  FIG. 4 is a configuration diagram illustrating the configuration of the digital calculation unit 30 of the waveform generation unit 22.

  The digital arithmetic unit 30 includes a slope register 50, an adder 52, and an addition register 54.

  The inclination register 50 receives waveform data indicating inclination through the data line 44 and stores the input waveform data. The adder 52 adds the value of the inclination register 50 and the value of the addition register 54. The addition register 54 stores the addition result of the adder 42. The value stored in the addition register 54 is output to the D / A converter 32 as a digital drive waveform and returned to the adder 52. Thereby, the digital calculation unit 30 can accumulate and output the value of the inclination register 50.

  Next, the operation of the present embodiment will be described.

  First, the waveform data generation unit 14 generates waveform data for a plurality of types of drive waveforms (three types of drive waveforms in the present embodiment) that are simultaneously generated by the plurality of waveform generation units 22. Here, for convenience, the three types of drive waveforms are referred to as waveform 1, waveform 2, and waveform 3 to distinguish them.

  FIG. 5A is a graph showing the waveforms 1, 2, and 3 with the driving voltage value on the vertical axis and time on the horizontal axis, and FIG. 5B shows the waveforms 1, 2, and 3 respectively. Is a waveform data indicating the slope of the partial wavelength and the time length when. In FIG. 5C, calculation formulas for calculating waveform data of inclination and time length are listed. Further, the voltage value and time shown in FIG. 5A are examples, and the present invention is not limited to these.

  First, when information about three drive waveforms is input from the CPU 12, the waveform data generation unit 14 determines a change point at which the slope, which is the amount of change in voltage per unit time, changes for each drive waveform from this information. Extract. As shown in FIG. 5A, in the waveform 1, since the inclination changes at times t0, t2, t6, t8, t11, and t12, these six change points are extracted. In the waveform 2, since the inclination changes at times t1, t4, t5, t7, t18, t10, and t13, these seven change points are extracted. In waveform 3, since the slope changes at times t3, t5, t6, t9, t10, and t12, these six change points are extracted.

  Next, the waveform data generation unit 14 generates waveform data indicating the inclination of the partial waveform when each drive waveform is divided at the change points extracted for each drive waveform for each drive waveform. In addition, waveform data indicating the time length of each partial waveform is also generated. In the present embodiment, the time length of the partial waveform is divided by the period of the reference clock and expressed by the number of reference clocks. Hereinafter, the number of reference clocks representing the time length of the partial waveform is referred to as the number of additions. The reference clock can be 10 MHz, for example.

More specifically, as shown in FIG. 5C, in the waveform 1, the number of additions W1c2 indicating the period between the change points between the times t0 and t2 is calculated by the following equation.
Number of additions W1c2 = (t2−t0) / reference clock In addition, the slope W1g2 of the partial waveform between the change points of time t0 and t2 in the waveform 1 is calculated by the following equation.

Inclination W1g2 = (V (t2) -V (t0)) / W1c2
Here, V (tn) indicates a voltage value at time tn.

  The time length and slope of other partial waveforms are calculated in the same manner.

  Thereby, the waveform data generation unit 14 has waveform data indicating the slope of each partial waveform when each of the waveforms 1, 2, and 3 is divided at each change point as shown in FIG. Waveform data indicating the time length (number of additions) is generated. At this time, each waveform data is arranged in time series.

  The waveform data adjustment unit 16 adjusts the waveform data of each waveform generated by the waveform data generation unit 14.

  FIG. 6 is a flowchart showing a flow of adjustment processing executed by the waveform data adjustment unit 16.

  In step 100, n and N are set to 0, and x is set to 1. Here, n is a parameter for identifying the time of the change point, and N is used as an address number for designating a storage area when storing in the waveform data storage unit 18. X is used as a parameter for identifying the drive waveform.

  In step 102, all the change points are arranged in time series based on the waveform data of each drive waveform.

  FIG. 7 is an enlarged view of the three types of drive waveforms shown in FIG. As shown in FIG. 7, there are six changing points of waveform 1 at times t0, t2, t6, t8, t11, and t12, and changing points of waveform 2 are times t1, t4, t5, t7, t18, There are seven t10 and t13, and there are six changing points of waveform 3 at times t3, t5, t6, t9, t10, and t12. Therefore, if all the change points in the three types of drive waveforms are extracted and arranged in time series, there are 14 times t0 to t13. In this change point extraction / array processing, for example, for each drive waveform, waveform data indicating the length of time (number of additions) is converted into a cumulative addition number indicating the time from time 0, and this is a small value. From

  In step 104, waveform data indicating the slope of the period from time 0 to the first change point (time t0) and waveform data indicating the time length are stored in the address N of the storage unit 36 of the waveform data storage unit 18 (N in step 100). Since 0 is set in, it is stored in the storage area indicated by address 0) here.

  Specifically, as shown in FIG. 8A, all of the waveform data W1g1, W2g1, and W2g1 indicating the initial slopes of the waveforms 1, 2, and 3 are converted to the time as shown in FIG. Waveform data indicating the slope of the period from 0 to the first change point t0 is stored together in the storage area indicated by address 0 of the storage unit 36 of the waveform data storage unit 18.

  Further, in the same address area, waveform data indicating the time length of the period from time 0 to the first change point t0 (that is, a portion divided at the change points at time 0 and t0) following the waveform data indicating the slope. Data indicating the time length of the waveform) is also stored. Here, in order to be able to read each waveform data of the same period at the same time in a batch, it is not stored in the storage area of different addresses (discontinuous storage area), but the storage area of the same address (continuous storage) Area).

  As a result, the selector 38 can read out the waveform data of the same period all at once, and distributes the read data from the first bit to the predetermined number of bits of the waveform data and outputs it to each data line 44. The waveform data of the same period can be output to the data line 44 at the same timing.

  In step 106, N is incremented by one.

  In step 108, it is determined whether or not the slope of the drive waveform x has changed before and after time tn. Here, if the cumulative number of additions at time tn matches any of the cumulative number of additions at each change point of the drive waveform x, it is determined that the slope has changed, and if not, it changes. Judge that it is not.

  For example, the case where n = 1 and x = 1 (time t1, waveform 1) will be described as an example. In the waveform 1, as shown in FIG. 7, the slope does not change at time t1. This can be determined because the cumulative number of additions at time t1 is larger than the waveform data W1c1 of the number of additions of waveform 1 and smaller than W1c1 + W1c2. In this case, a negative determination is made at step 108, and the routine proceeds to step 112.

  When n = 2 and x = 1 (time t2, waveform 1), the slope of waveform 1 changes at time t2, as shown in FIG. This can be determined from the fact that the cumulative number of additions at time t2 matches W1c1 + W1c2 of the waveform data of the number of additions of waveform 1. In this case, an affirmative determination is made at step 108, and the routine proceeds to step 110.

  In step 110, waveform data indicating the slope after the change is stored in the storage area of the address N of the storage unit 36 of the waveform data storage unit 18 for the period from time tn to tn + 1. For example, when n = 2 and x = 1, the waveform data Wlg3 indicating the slope after the change (the slope at the times t2 to t3) is stored.

  In step 112, the waveform data showing the same slope as that of the immediately preceding period is stored in the storage area of the address N of the storage unit 36 of the waveform data storage unit 18 for the period from time tn to tn + 1. For example, in the case of n = 1 and x = 1, the waveform data Wlg2 indicating the same inclination as the immediately preceding period (inclination at times t0 to t1) is stored.

  After step 110 or 112, in step 114, x is incremented by one.

  In step 116, it is determined whether or not x exceeds the total number of drive waveforms (here, 3).

  If it is determined in step 116 that x does not exceed the total number of drive waveforms, the process returns to step 108 and the above processing is repeated for the drive waveform x. Here, when storing the waveform data, the waveform data of the same period of different drive waveforms are stored in the storage area of the same address, so that all the waveform data of the same period can be read out collectively.

If it is determined in step 116 that x has exceeded the total number of drive waveforms, the process proceeds to step 118 and the time length of the period from time tn to tn + 1 (that is, changes in time tn and tn + 1). Waveform data indicating the number of additions, which is the time length of the partial waveform divided by points, is stored in the storage area at address N. Here, the waveform data indicating the time length is calculated by subtracting the cumulative addition count from time 0 to tn from the cumulative addition count from time 0 to tn + 1. Thereby, for example, as the waveform data C2 indicating the time length from time t0 to t1, the number of additions equivalent to the number of additions calculated by the following equation is obtained.
Number of additions C2 = (t1−t0) / reference clock As a result, the number of additions C1 to C15 common to the drive waveforms is obtained as shown in FIG. 8B.

  In step 120, it is determined whether or not n exceeds the total number of change points (14 in the present embodiment).

  If it is determined in step 120 that n does not exceed the total number of change points, it is determined that waveform data has not been generated for all partial waveforms divided at all change points, and the process proceeds to step 122. N and N are incremented by 1, and x is set to 1. Then, the process returns to step 108.

  Thereby, the waveform data indicating the slope and the waveform data indicating the time length can be generated and stored for the partial waveform of each drive waveform in the next period.

  On the other hand, if it is determined in step 120 that n has exceeded the total number of change points, it is determined that waveform data generation has been completed for all of the partial waveforms divided at all the change points, and the waveform data adjustment unit 16 finishes the adjustment process of the waveform data.

  That is, the waveform data adjustment unit 16 generates waveform data for partial waveforms obtained by dividing each drive waveform at all the change points in each drive waveform from the waveform data shown in FIG. And the waveform data indicating the time length are collectively stored in the storage unit 36 in the same address area. Here, since the waveform data indicating the time length is common among the drive waveforms, it is not necessary to store the waveform data indicating the time length for each drive waveform.

  Thus, as shown in FIG. 8A, the waveform data of the partial waveform when each drive waveform is divided at the change points for each drive waveform is the partial waveform when the drive waveform is divided at all the change points in all the drive waveforms. In the state as shown in FIG. 8B, the storage area of each address in the storage section 36 of the waveform data storage section 18 (in this embodiment, 15 storage addresses from 0 to 14 are stored). Stored in each of the regions).

  When the waveform data (number of additions and inclination) adjusted as described above is stored in the waveform data storage unit 18, a plurality of drive waveforms are generated simultaneously as follows.

  First, at the start of the waveform generation operation, the control signal generation unit 42 of the control unit 20 outputs a read signal to the waveform data storage unit 18 via the control line 46 and outputs address information via the address line 48.

  When a read signal is input to the selector 38 of the waveform data storage unit 18, the waveform data stored at the address of the storage unit 36 specified by the address information is read in a batch, and the read is performed via the data line 44. Among the waveform data, the waveform data indicating the inclination is output to the corresponding inclination register 50 of the digital arithmetic unit 30, and the waveform data indicating the length of time (number of additions) is output to the addition number counter 40 of the control unit 20.

  It should be noted that here, the data read in a lump is cut out for each predetermined number of waveform data from the first bit and output to each data line 44, so that each waveform data is added to the slope register 50 and added at the same timing. It outputs to the number counter 40 and stores it.

  The addition counter 40 of the control unit 20 counts down the stored waveform data (addition count) according to the reference clock.

  On the other hand, in the digital arithmetic unit 30, when the waveform data (slope) is stored in the slope register 50, the adder 52 adds the value of the addition register 54 and the waveform data stored in the slope register 50 according to the reference clock. And output to the addition register 54. In this way, the digital calculation unit 30 performs an accumulation process on the waveform data. In the digital operation unit 30, the same waveform data is accumulated until new waveform data is stored in the inclination register 50.

  The accumulated value accumulated by the digital operation unit 30 is output as a digital drive waveform to the D / A conversion unit 32. The D / A conversion unit 32 converts the digital drive waveform into an analog drive waveform and amplifies the power. The unit 34 amplifies the analog drive waveform to the power necessary for head driving, and supplies the amplified drive waveform to the recording head 26 via the waveform selection unit 24.

  When the addition number counter 40 of the control unit 20 becomes 1, the control signal generation unit 42 of the control unit 20 outputs to the waveform data storage unit 18 address information specifying a read signal and an address incremented by one. As a result, new waveform data (slope) is stored in the slope register 50 of the digital arithmetic unit 30, and this waveform data is accumulated thereafter. At the same time, new waveform data (number of additions) is stored in the addition counter 40 of the control unit 20 and is down-counted according to the reference clock.

  By repeating the above processing, a plurality of different drive waveforms can be simultaneously generated and output by the plurality of waveform generators 22.

  The drive waveform generation process described above will be described with reference to FIG. FIG. 9 is a timing chart in the control unit 20 and the digital calculation unit 30. Here, the timing chart of two digital arithmetic units 30 corresponding to waveform 1 and waveform 2 out of the three digital arithmetic units 30 will be described as an example.

  As shown in FIGS. 9C and 9D, when the read signal and the address information are output from the control signal generation unit 42 of the control unit 20, FIGS. 9A, 9E, and 9I are performed. As shown, the waveform data (the number of additions) indicating the time length of the partial waveform and the waveform data indicating the slope are collectively read from the designated address of the storage unit 36 of the waveform data storage unit 18.

  As a result, as shown in FIG. 9B, the waveform data (addition count) is stored in the addition count counter 40, and the addition count counter 40 counts down the stored addition count in accordance with the reference clock. At the same time, as shown in FIGS. 9F and 9J, waveform data (slope) is stored in the slope register 50 of the digital arithmetic unit 30 for waveform 1 and waveform 2, and each adder 52 9 (G) and (K), the stored waveform data (slope) is added to the value of the addition register 54 to accumulate, and as shown in FIGS. 9 (H) and (L), The accumulated value is output to each addition register 54.

  When the addition number counter of the control unit 20 becomes 1, the waveform data of the next address is read at once, the waveform data (number of additions) is stored in the addition number counter 40, and the digital calculation unit 30 Waveform data (slope) is stored in each of the slope registers 50. This is repeated until the end of printing.

As shown in FIG. 8A, when the waveform data of each driving waveform is divided at the changing points for each driving waveform, the waveform data of the partial waveform is stored for each driving waveform. The timing of reading each waveform data (slope) from the waveform data storage unit 18 when generating a drive waveform by the plurality of waveform generation units 22 is as follows.
Waveform 1: t0, t2, t6, t8, t11, t12
Waveform 2: t1, t4, t5, t7, t8, t10, t13
Waveform 3: t3, t5, t6, t9, t10, t12
It becomes. There is no problem if all the read timings are deviated, but if a read to one waveform data storage unit 18 occurs at the same timing, a delay occurs in the read.

  On the other hand, as described above, the waveform data adjustment unit 16 generates partial waveform data when each drive waveform is divided at all change points in the entire drive waveform as shown in FIG. 8B. If the waveform data for the same period is stored together, only one storage means is required, and the waveform data can be read all at once, eliminating the read delay.

  That is, when the waveform data (slope) is read at the changing point of the waveform 1 (for example, time t0) to generate the waveform 1, the waveform data (slope) can also be read simultaneously for the waveform 2 and the waveform 3. The other waveforms 2 and 3 other than the waveform 1 are also divided at the change points to generate waveform data.

  Similarly, the waveform data of waveform 1 and waveform 3 can be read simultaneously when the waveform data is read at the change point of waveform 2, and the waveform is simultaneously read when waveform data is read at the change point of waveform 3. The waveform data is generated by dividing all the drive waveforms at the change points so that the waveform data of 1 and waveform 2 can be read out.

When the waveform data is generated in this way, as shown in FIGS. 8A and 8B, the number of times of reading the waveform data of each drive waveform is
Waveform 1: 6 times-> 14 times Waveform 2: 7 times-> 14 times Waveform 3: 6 times-> 14 times Although the number of additions can be made common, the memory capacity can be reduced.

  Further, since waveform data of a plurality of drive waveforms can be obtained simultaneously by one reading, an arbiter for reading arbitration is not necessary, and waveform data can be read with a simple configuration. Thereby, there is no delay in waveform generation. Also, the address line and control line for the waveform data storage unit can be shared.

  The waveform generator may change the waveform data according to the temperature.

  In the above-described embodiment, the case where ink is used as droplets has been described as an example. However, the present invention is not limited to this, and instead of ink, for example, improvement of image density, prevention of intercolor bleeding, etc. The present invention can also be applied to the case where the reaction liquid for discharging is discharged. In addition, the present invention can be applied to the application of the alignment film forming material, the application of the flux, the application of the adhesive, and the like in the same manner as described above by the inkjet method.

  In this embodiment, an example in which the waveform generation device is provided in a droplet discharge device that discharges droplets has been described. However, the present invention is not limited thereto, and may be provided, for example, in a device that outputs sound. it can.

It is a block diagram of the droplet discharge apparatus containing the waveform generation apparatus of this Embodiment. It is a block diagram of a waveform generation apparatus. It is a block diagram of a waveform data storage part and a control part. It is a block diagram of the data calculating part of a waveform generation part. It is explanatory drawing explaining a process when a waveform data generation part produces | generates waveform data. It is a flowchart which shows the flow of the adjustment process which a waveform data adjustment part performs. It is the figure which expanded and showed three types of drive waveforms shown to FIG. 5 (A). It is explanatory drawing explaining a process when a waveform data adjustment part adjusts waveform data. It is a timing chart in a control part and a digital calculating part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Waveform generation apparatus 14 Waveform data generation part 16 Waveform data adjustment part 18 Waveform data storage part 20 Control part 22 Waveform generation part 24 Waveform selection part 26 Recording head 30 Digital operation part 36 Storage part 38 Selector 40 Addition number counter 42 Adder 42 Control signal generator 44 Data line 46 Control line 48 Address line 50 Inclination register 52 Adder 54 Addition register 100 Droplet ejection device

Claims (6)

All of the change points where the slope, which is the amount of change in voltage per unit time, is extracted from a plurality of types of voltage waveforms generated at the same time, and each of the plurality of types of voltage waveforms is divided at each of the extracted change points. Generating means for generating waveform information of a predetermined number of bits indicating the slope of the partial waveform at the time,
The waveform information of each partial waveform in the same period of the generated plural types of voltage waveforms is continuously stored so that the waveform information of the partial waveforms in the same period of the plurality of types of voltage waveforms can be collectively read. Storage means stored in the area ;
A plurality of waveform generating means provided corresponding to each of the plurality of types of voltage waveforms and generating the corresponding voltage waveforms by accumulating the waveform information of the input partial waveforms for the time length of the partial waveforms. When,
Each piece of waveform information of the partial waveform of the same period is read from the storage means at a time , and the read waveform information data of each partial waveform of the same period is the predetermined bit from the first bit. Control means for cutting out each number and controlling each of the cut-out waveform information to be input to each of the corresponding waveform generation means of the plurality of waveform generation means at the same timing ;
A waveform generator comprising: When the time length of the partial waveform corresponding to the waveform information has elapsed since the waveform information was read from the storage means and input to the plurality of waveform generation means, the control means Waveform information is read out in a lump , and the read waveform information data of each partial waveform in the same period is cut out from the first bit for each of the predetermined number of bits, and the cut out waveform Each of the information is controlled to be input to each of the corresponding waveform generating means of the plurality of waveform generating means at the same timing ,
2. The waveform generator according to claim 1, wherein each of the plurality of waveform generating means generates a voltage waveform by cumulatively adding the input waveform information until the next waveform information is input. In the storage means, time information indicating the time length of each of the partial waveforms is stored,
3. The waveform generator according to claim 2, wherein the control unit controls reading of the waveform information from the storage unit and input of the waveform information to the waveform generation unit based on time information stored in the storage unit.   The generating means extracts all of the change points in a plurality of types of waveforms to be generated simultaneously, arranges the extracted change points in time series, and sets the change points for each of the plurality of types of voltage waveforms. It is determined whether or not the slope has changed before and after, and for a partial waveform in the period from the change point at which the slope has been changed to the next change point of the change point, a waveform indicating the slope after the change The waveform information indicating the same inclination as that of the immediately preceding period is generated for the partial waveform in the period from the change point at which the inclination is determined not to change to the next change point. The waveform generator of any one of Claims. The waveform generator according to any one of claims 1 to 4,
Discharge means for discharging droplets based on the voltage waveform generated by the waveform generator;
A droplet discharge device comprising: Extracting all change points at which the slope, which is the amount of change in voltage per unit time, in a plurality of types of voltage waveforms generated simultaneously; and
Generating waveform information of a predetermined number of bits indicating a slope of a partial waveform when each of the plurality of types of voltage waveforms is divided at each extracted change point;
The waveform information of each partial waveform in the same period of the generated plural types of voltage waveforms is stored in the storage means so that the waveform information of each partial waveform in the same period of the plurality of types of voltage waveforms can be read collectively . Storing in a continuous storage area ;
Each piece of waveform information of the partial waveform of the same period is collectively read from the storage means, and the read waveform information data of each partial waveform of the same period is extracted from the first bit for each predetermined number of bits. provided corresponding to each of the plurality of types of voltage waveforms, corresponding the plurality of waveform generating means for generating a voltage waveform by accumulating time length of the waveform information of the input portion waveform partial waveform Inputting each of the extracted waveform information to each of the waveform generating means at the same timing ;
A waveform generation control method including:

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