JP2009196250A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform the switching from a non-delivery waveform to a delivery waveform without needing useless delivery data. <P>SOLUTION: An inkjet recording device is equipped with: a head part 2 which drives a nozzle 21 by the inputting of a drive waveform Sw, delivery data Sd, a clock signal Sc and a latch signal Sl; a delivery waveform formation part 31 which forms a delivery waveform Swa for making an ink discharged from the nozzle 21; a non-delivery waveform formation part 32 which forms the non-delivery waveform Swb for making the ink swing in the nozzle 21; a waveform selecting signal formation part 34 which outputs the first waveform selecting signal Ska from the clock signal Sc; and a drive waveform selecting means 35 which selects the delivery waveform Swa as the drive waveform Sw from the first waveform selecting signal Ska and outputs it to the head part 2. The waveform selecting signal formation part 34 outputs the first waveform selecting signal Ska, in the case where the clock signal Sc is outputted to the head part 2 when the non-delivery waveform Swb has been selected as the drive waveform Sw. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus.

  2. Description of the Related Art Conventionally, many image recording apparatuses using an ink jet method have been used as image recording means capable of recording an image simply and inexpensively. An image recording apparatus using the ink jet method (hereinafter referred to as an ink jet recording apparatus) uses, for example, a piezoelectric element such as a piezo element to eject ink droplets from a nozzle of a recording head toward a recording medium. An image is recorded while the ink is landed on the recording medium by forming an electrostatic field in the gap and pulling an ink droplet from the nozzle by an electric suction force.

  By the way, in this ink jet recording apparatus, in particular, an on-demand type ink jet recording apparatus in which ink droplets are ejected from the nozzle only during recording, the ink solvent evaporates by exposing the ink in the nozzle opening to the atmosphere for a long time. The nozzle may be clogged. In this respect, even if the cap was put on the head when the printing operation was not performed to prevent the ink from being dried, it was not sufficient as a countermeasure, and the nozzle could be clogged even during the printing operation. .

  Therefore, in order to prevent such a problem, a technique for performing preliminary ejection at a position deviated from the recording medium (see, for example, Patent Document 1), a print mode for printing image information, and an ink discharge mode for discharging ink. A technique (for example, refer to Patent Document 2) that switches and controls each of a plurality of heads has been proposed.

  However, in the above technique, since the ink ejection timing is different between the preliminary ejection or the ink discharge mode and the normal printing, it is difficult to synchronize the head drive waveform when switching between these. It is possible to synchronize the drive waveform if this switching is performed by signal input from the control board of the main body of the apparatus to the head unit. there were.

On the other hand, in Patent Document 3, for example, as shown in FIG. 7, the waveform selection means provided on the head substrate discharges the ink for discharging the ink for printing and the ink in the nozzle for preventing drying. A configuration has been proposed in which a non-ejection waveform to be oscillated is appropriately selected based on an ejection start signal from a control substrate and output to the head unit. With such a configuration, the load on the control board is reduced and high-speed switching is enabled.
JP-A-11-105304 JP 2004-9358 A JP 2007-320081 A

  However, in the technique described in Patent Document 3, as shown in FIG. 7, when the drive waveform of the head unit is switched from the non-ejection waveform to the ejection waveform, the waveform selection signal becomes the ejection waveform side by the ejection start signal. However, the drive waveform is not immediately switched to the discharge waveform, and is delayed at least one cycle from the first discharge start signal in order to ensure a time for the meniscus state of the ink in the nozzle to return to the normal state from the previous drive state. It was switched to the discharge waveform. Further, since the ejection start signal is output after the transfer of each ink ejection data is completed, useless dummy data (data surrounded by a triangle in FIG. 7) which is irrelevant to the image formation is printed by this delay. It was necessary to add in advance to the head of the discharge data.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink jet recording apparatus capable of switching from a non-ejection waveform to an ejection waveform without requiring useless ejection data.

In order to solve the above-mentioned problem, the invention according to claim 1
An inkjet recording apparatus that forms an image by discharging ink from a plurality of nozzles,
A drive waveform indicating the type of drive to be performed by the nozzle having the nozzle, discharge data including ink discharge information for each nozzle, a synchronization signal for transferring the discharge data, and completion of transfer of the discharge data A head unit that performs a predetermined drive on the nozzle by receiving a latch signal;
An ejection waveform generation unit that generates an ejection waveform for ejecting ink from the nozzle as one type of the drive waveform;
A non-ejection waveform generator for generating a non-ejection waveform for causing ink to oscillate in the nozzle as one type of the driving waveform;
Waveform selection for outputting a first waveform selection signal for selecting the ejection waveform as the drive waveform based on a predetermined type of signal input to the head unit in relation to the transfer of the ejection data to the head unit A signal generator;
Drive waveform selection means for selecting the ejection waveform as the drive waveform based on the first waveform selection signal and outputting the drive waveform to the head unit;
With
The waveform selection signal generation unit outputs the first waveform selection signal when the predetermined type of signal is input to the waveform selection signal generation unit when the non-ejection waveform is selected as the drive waveform. It is characterized by doing.

Invention of Claim 2 is the inkjet recording device of Claim 1, Comprising:
The predetermined type of signal is any one of the ejection data, the transfer synchronization signal, and the latch signal.

Invention of Claim 3 is an inkjet recording device of Claim 2, Comprising:
The predetermined type of signal is the ejection data.

Invention of Claim 4 is an inkjet recording device as described in any one of Claims 1-3, Comprising:
When the waveform selection signal generation unit does not input at least one of a discharge start signal, which is a start signal of the discharge waveform, and the latch signal for the head unit to the discharge waveform generation unit for a predetermined time, the drive waveform A second waveform selection signal for selecting the non-ejection waveform as
The drive waveform selection unit selects the non-ejection waveform as the drive waveform based on the second waveform selection signal, and outputs the drive waveform to the head unit.

Invention of Claim 5 is an inkjet recording device of Claim 4, Comprising:
A switching time changing unit for changing the predetermined time is provided.

Invention of Claim 6 is an inkjet recording device as described in any one of Claims 1-5, Comprising:
A non-ejection interval changing unit for changing a time interval at which the non-ejection waveform is output;
A non-ejection timing generation unit that generates a signal of the time interval and outputs the signal to the non-ejection waveform generation unit.

  According to the first aspect of the present invention, when a predetermined type of signal related to the transfer of ejection data is input when the non-ejection waveform is selected as the driving waveform, the waveform selection signal generation unit generates the driving waveform. Since the first waveform selection signal for selecting the ejection waveform is output as the first waveform selection signal, a predetermined type of signal is transferred for at least one cycle after the first waveform selection signal is output, and the drive waveform is actually input. In the meantime, the meniscus state of the ink in the nozzle is restored to a normal state. Therefore, it is possible to switch from the non-ejection waveform to the ejection waveform without requiring unnecessary ejection data corresponding to the delayed signal to ensure the time for the meniscus state to recover.

  According to the second aspect of the present invention, since the predetermined type of signal is any one of ejection data, a transfer synchronization signal, and a latch signal, until these signals are output to the head, The non-ejection waveform remains selected as the driving waveform. Therefore, the ink in the nozzle is swung by this non-ejection waveform to prevent drying.

  According to the third aspect of the present invention, since the predetermined type of signal is ejection data, the non-ejection waveform remains selected as the driving waveform until the ejection data is output to the head unit. . Therefore, the ink in the nozzle is swung by this non-ejection waveform to prevent drying.

  According to a fourth aspect of the present invention, the waveform selection signal generation unit has at least one of a discharge start signal, which is a discharge waveform start signal for the discharge waveform generation unit, and a latch signal for the head unit. When no time is input, a second waveform selection signal for selecting a non-ejection waveform is output as the driving waveform, and the driving waveform selection means selects the non-ejection waveform as the driving waveform based on the second waveform selection signal. Since the drive waveform is output to the head unit, the non-discharge waveform is always input except when the discharge waveform is input as the drive waveform to the head unit. Therefore, drying of the ink in the nozzle can be stably prevented.

  According to the invention described in claim 5, since the switching time changing unit for changing the predetermined time is provided, the switching time from the discharge waveform to the non-discharge waveform can be arbitrarily changed. Therefore, even when the degree of drying or the ejection waveform changes due to a change in ink or the like, an appropriate switching time for preventing drying can be set.

  According to the invention described in claim 6, a non-ejection interval changing unit that changes a time interval in which a non-ejection waveform is output, and a non-ejection timing that generates a signal of the time interval and outputs the signal to the non-ejection waveform generation unit. Since the generator is provided, the cycle of the non-ejection waveform can be arbitrarily changed. Therefore, even when the degree of drying changes due to a change in ink or the like, an appropriate waveform cycle for preventing drying can be set.

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

  First, the control configuration of the inkjet recording apparatus 1 in the present embodiment will be described with reference to the block diagram of FIG. As shown in FIG. 1, the inkjet recording apparatus 1 includes a plurality of nozzles 21, a head unit 2 that controls the nozzles 21, and a head drive control unit 3 that outputs various signals for driving the head unit 2. And a device control unit 4 that is provided in a device main body (not shown) and outputs a signal such as an ejection start signal to the head drive control unit 3.

  The head unit 2 includes a drive waveform Sw indicating the type of drive to be performed by the nozzle 21, discharge data Sd including ink discharge information for each nozzle 21, a clock signal Sc that is a synchronization signal for transferring the discharge data Sd, The nozzle 21 is driven in a predetermined manner by receiving a latch signal S1 indicating completion of the transfer of the ejection data Sd. Specifically, a piezo element (not shown) provided in each nozzle 21 vibrates based on the drive waveform Sw, the ejection data Sd, the clock signal Sc, and the latch signal Sl, so that the ink from the nozzle 21 is obtained. The ink is swung within the nozzle 21 to the extent that droplets are discharged or not discharged.

  The apparatus control unit 4 outputs the above-described ejection data Sd, latch signal S1, and clock signal Sc to the head unit 2 via the head drive control unit 3, and also outputs an ejection start signal Sf which is an ink ejection timing signal. The data is output to the head drive control unit 3. The apparatus control unit 4 includes a switching time changing unit 41 and a non-ejection interval changing unit 42. The switching time changing unit 41 can change the non-ejection switching time Ts when the drive waveform Sw is switched from a later-described ejection waveform Swa to a non-ejection waveform Swb. The non-ejection interval changing unit 42 can change a non-ejection time interval Ti that is a time interval at which the non-ejection waveform Swb is output. The non-ejection switching time Ts and the non-ejection time interval Ti are output to the head drive control unit 3. The non-ejection switching time Ts is preferably set to 1 second or less as the time during which the ink in the nozzles 21 does not adhere.

  The head drive control unit 3 includes an ejection waveform generation unit 31, a non-ejection waveform generation unit 32, a non-ejection timing generation unit 33, a waveform selection signal generation unit 34, and a drive waveform selection unit 35. The head drive control unit 3 is not particularly limited, but can be provided, for example, on a carriage (not shown) on which the head unit 2 is mounted.

  Next, each component of the head drive control unit 3 described above will be described in detail.

  The ejection waveform generation unit 31 outputs the ejection waveform Swa, which is one type of the drive waveform Sw, that ejects ink from the nozzles 21 to the drive waveform selection unit 35 in synchronization with the ejection start signal Sf input from the apparatus control unit 4. (See FIG. 3). As shown in the waveform example of FIG. 2A, the discharge waveform Swa is a waveform that becomes negative by a predetermined amount after the voltage becomes positive by a predetermined amount. The piezoelectric element of the head unit 2 contracts in the plus part of the ejection waveform Swa, and conversely expands in the minus part. Therefore, in the portion where the ejection waveform Swa varies from plus to minus, the piezo element is deformed from the contracted state to the expanded state, and ink is ejected from the nozzle 21.

  The non-ejection waveform generation unit 32 is a kind of drive waveform Sw and synchronizes a non-ejection waveform Swb that causes ink to oscillate in the nozzles 21 with a non-ejection timing signal St (described later) input from the non-ejection timing generation unit 33. And output to the drive waveform selection means 35 (see FIG. 3). This non-ejection waveform Swb is a waveform that becomes 0 after the voltage becomes positive by a predetermined amount as shown in the waveform example of FIG. In the plus part of the non-ejection waveform Swb, the piezo element of the head unit 2 contracts, and in the part where the plus part changes from 0, the piezo element returns from the contracted state to the original state, so that the ink is not ejected from the nozzle 21. It swings in the nozzle 21. However, the non-ejection waveform Swb is not limited to the waveform that causes the ink to oscillate as described above, and may be a waveform that slightly oscillates the ink so that the ink is not ejected from the nozzle 21.

  As shown in FIG. 1, the non-ejection timing generation unit 33 generates a signal having a period of the non-ejection time interval Ti input from the apparatus control unit 4 and a non-ejection timing signal that is a timing signal of the non-ejection waveform Swb. As St, it outputs to the non-ejection waveform generation part 32 (refer FIG. 3).

  The waveform selection signal generation unit 34 selects one of the two types of waveform selection signals Sk based on the clock signal Sc, the latch signal Sl, and the non-ejection switching time Ts input from the device control unit 4. To output. The two types of waveform selection signals Sk are a first waveform selection signal Ska for selecting the ejection waveform Swa as the drive waveform Sw and a second waveform selection signal for selecting the non-ejection waveform Swb as the drive waveform Sw. The waveform selection signal generator 34 always outputs any one of them. Here, the first waveform selection signal Ska and the second waveform selection signal Skb are not particularly limited, but are switched by changing the voltage value between Low and High as shown in FIG. . Note that the second waveform selection signal Skb is output when the ink jet recording apparatus 1 is powered on.

More specifically, in the waveform selection signal generator 34, as shown in FIG. 3, switching between the two types of waveform selection signals Sk is performed as follows.
First, switching of the output from the second waveform selection signal Skb to the first waveform selection signal Ska will be described. When the waveform selection signal generation unit 34 outputs the second waveform selection signal Skb, that is, when the non-ejection waveform Swb is selected as the drive waveform Sw, the clock signal Sc is input to the waveform selection signal generation unit 34. Then, the waveform selection signal generation unit 34 switches to output the first waveform selection signal Ska.
Next, switching of the output from the first waveform selection signal Ska to the second waveform selection signal Skb will be described. The waveform selection signal generator 34 has timer means 341 that can measure and compare time. The timer means 341 measures the time during which the latch signal Sl is not input from the device control unit 4 when the first waveform selection signal Ska is being output, and the measurement time and the device control unit 4 in advance. The input non-discharge switching time Ts is compared. Then, when the measurement time reaches the non-ejection switching time Ts, that is, when the latch signal S1 is not input during the non-ejection switching time Ts, the waveform selection signal generator 34 outputs the second waveform selection signal Skb. Switch to. The timer unit 341 stops measuring time while the second waveform selection signal Skb is being output.

  The trigger signal when switching to the output of the first waveform selection signal Ska is not limited to the clock signal Sc, and may be a signal related to the transfer of the ejection data Sd to the head unit 2. Therefore, the latch signal S1 may be used as the trigger signal, or the ejection data Sd may be used by inputting the ejection data Sd to the waveform selection signal generator 34 (see FIG. 1). Here, when switching to the first waveform selection signal Ska is performed based on the ejection data Sd and the latch signal Sl, for example, even if the switching is suddenly made to the non-ejection waveform Swb during the output of the ejection waveform Swa, generally Since the non-ejection waveform Swb has a low potential, there is no possibility that a FET (Field Effect Transistor) (not shown) of the head unit 2 will cause latch-up. In addition, when switching to the output of the second waveform selection signal Ska, the timer means 341 may measure a time during which the ejection start signal Sf is not input instead of the latch signal S1.

  As shown in FIG. 1, the drive waveform selection unit 35 generates the discharge waveform Swa input from the discharge waveform generation unit 31 and the non-discharge waveform generation based on the waveform selection signal Sk input from the waveform selection signal generation unit 34. One of the non-ejection waveforms Swb input from the unit 32 is output to the head unit 2 as a drive waveform Sw. Specifically, when the first waveform selection signal Ska is input as the waveform selection signal Sk from the waveform selection signal generation unit 34, the ejection waveform Swa is selected as the drive waveform Sw and output to the head unit 2. When the second waveform selection signal Skb is input as the waveform selection signal Sk from the waveform selection signal generation unit 34, the non-ejection waveform Swb is selected as the drive waveform Sw and output to the head unit 2.

Here, regarding the transfer timing of the clock signal Sc, the ejection data Sd, and the latch signal Sl as signals relating to the transfer of the ejection data Sd to the head section 2 among the signals input to the head section 2, FIG. Description will be made with reference to a) and (b). FIG. 4A is a timing chart showing an example of transfer of these signals, and FIG. 4B is an enlarged view of one waveform period (dashed line portion A) in FIG.
As shown in FIGS. 4A and 4B, the ejection data Sd is transferred in synchronization with the clock signal Sc. The ejection data Sd is binarized dot pattern data, and is transferred to a register (not shown) of the head unit 2 for each group of nozzles 21 (n in FIG. 4B) to be synchronized, and the latch signal S1. Is latched by. When the process is completed up to this point, ink can be ejected from the nozzles 21 in accordance with the transferred ejection data Sd. When the ejection waveform Swa is input to the head unit 2 as the drive waveform Sw, ink droplets are ejected from the nozzle 21.

  Next, the operation of the inkjet recording apparatus 1 in the present embodiment will be described with reference to FIGS.

  First, when the ink jet recording apparatus 1 is turned on, the waveform selection signal generation unit 34 outputs the second waveform selection signal Skb to the drive waveform selection means 35. The drive waveform selection means 35 outputs a non-ejection waveform Swb to the head unit 2 as the drive waveform Sw based on the input second waveform selection signal Skb. The head unit 2 is swung to the extent that the ink in the nozzles 21 is not ejected by the non-ejection waveform Swb, so that drying of the ink is prevented.

  At this time, the waveform selection signal generation unit 34 continues to output the second waveform selection signal Skb until the clock signal Sc is output from the device control unit 4. Therefore, the output of the non-ejection waveform Swb is also continued, and the nozzle 21 is continuously oscillated at the non-ejection time interval Ti. However, the non-ejection time interval Ti can be arbitrarily changed by the non-ejection interval changing unit 42 of the apparatus control unit 4.

  Next, when the clock signal Sc is output from the apparatus control unit 4 and input to the waveform selection signal generation unit 34, the waveform selection signal generation unit 34 outputs the first waveform selection signal Ska to the drive waveform selection means 35. Switch to. On the other hand, the ejection data Sd starts to be transferred to the head unit 2 in synchronization with the clock signal Sc, and when the first data bundle has been transferred to the head part 2, this data bundle is latched by the latch signal S1. Then, the drive waveform selection means 35 outputs the ejection waveform Swa synchronized with the ejection start signal Sf to the head unit 2 as the drive waveform Sw based on the first waveform selection signal Ska. The head unit 2 discharges ink droplets from the nozzles 21 in accordance with the transferred discharge data Sd using the discharge waveform Swa.

  As described above, when the non-ejection waveform Swb is selected as the drive waveform Sw, the waveform selection signal generation unit 34 outputs the ejection waveform as the drive waveform Sw when the clock signal Sc is input to the waveform selection signal generation unit 34. A first waveform selection signal Ska for selecting Swa is output. Thus, after the first waveform selection signal Ska is output, the first data bundle of the discharge data Sd is transferred and latched, and the discharge waveform Swa is actually input to the head unit 2 as the drive waveform Sw. In the meantime, the meniscus state of the ink in the nozzle 21 is restored from the swinging state to the normal state.

  Here, when the first waveform selection signal Ska is output from the waveform selection signal generation unit 34, the timer unit 341 starts measuring time and comparing the measurement time and the non-ejection switching time Ts. Since this measurement time is reset every time the latch signal S1 is input, it becomes less than the non-ejection switching time Ts while the ejection data Sd is transferred, and the waveform selection signal generator 34 outputs the first waveform selection signal Ska. Keep doing. Then, after all the ejection data Sd (seven data bundles in FIG. 3) has been transferred and the last latch signal S1 is input, when the measurement time by the timer means 341 reaches the non-ejection switching time Ts, that is, the latch signal When Sl is not input during the non-ejection switching time Ts, the waveform selection signal generation unit 34 switches to output the second waveform selection signal Skb. The drive waveform selection means 35 outputs a non-ejection waveform Swb to the head unit 2 based on the second waveform selection signal Skb, and the head unit 2 oscillates the ink in the nozzles 21 by this non-ejection waveform Swb. This state is continued until the clock signal Sc is output from the device control unit 4 again.

  As described above, when the latch signal S1 is not input during the non-ejection switching time Ts, the waveform selection signal generator 34 outputs the second waveform selection signal Skb for selecting the non-ejection waveform Swb as the drive waveform Sw. The drive waveform selection means 35 selects the non-ejection waveform Swb as the drive waveform Sw based on the second waveform selection signal Skb and outputs it to the head unit 2. Thereby, the non-ejection waveform Swb is always inputted except when the ejection waveform Swa is inputted as the drive waveform Sw to the head unit 2. Further, the non-ejection switching time Ts can be arbitrarily changed by the switching time changing unit 41 of the apparatus control unit 4.

  As described above, according to the ink jet recording apparatus 1 according to the present embodiment, the nozzles are output after the first waveform selection signal Ska is output until the ejection waveform Swa is actually input to the head unit 2. Since the meniscus state of the ink in 21 recovers from the oscillating state to the normal state, as in the conventional data transfer shown in FIG. 7, in order to secure time for the meniscus state to recover, what is image formation? It is possible to switch from the non-ejection waveform Swb to the ejection waveform Swa without adding unnecessary irrelevant dummy data (data surrounded by triangles in FIG. 7) to the head of the ink ejection data.

  In addition, since the non-ejection waveform Swb is always inputted except when the ejection waveform Swa is inputted as the drive waveform Sw to the head unit 2, it is possible to stably prevent the ink in the nozzles 21 from being dried.

  In addition, since the non-ejection time interval Ti can be arbitrarily changed by the non-ejection interval changing unit 42, an appropriate waveform cycle for preventing drying can be obtained even when the degree of drying changes due to, for example, ink change. Can be set.

  In addition, since the non-ejection switching time Ts can be arbitrarily changed by the switching time changing unit 41, even when the degree of drying or the ejection waveform Swa changes due to ink change or the like, the non-ejection waveform Swb is changed from the ejection waveform Swa. The time for switching to can be set to an appropriate time for preventing drying.

[Modification]
Next, an inkjet recording apparatus 5 as a modification of the above embodiment will be described. In addition, the same code | symbol is attached | subjected to the component similar to the said embodiment, and the description is abbreviate | omitted.

  As shown in the control configuration diagram of FIG. 5, the ink jet recording apparatus 5 includes a first head unit 6 </ b> A, a second head unit 6 </ b> B, a head drive control unit 7, and a device control unit 8.

  The first head unit 6A and the second head unit 6B are configured to include a first clock signal Sc1, a first latch signal Sl1, a first drive waveform Sw1, a first ejection data Sd1, a second clock signal Sc2, and a second latch signal. By inputting Sl2, the second drive waveform Sw2, and the second ejection data Sd2, the predetermined drive is independently performed for each of the plurality of nozzles 21 included therein. Here, the first and second clock signals Sc1 and Sc2, the first and second latch signals Sl1 and Sl2, the first and second drive waveforms Sw1 and Sw2, and the first and second ejection data Sd1 and Sd2, respectively, It is a signal having the same properties as the clock signal Sc, the latch signal Sl, the drive waveform Sw, and the ejection data Sd in the embodiment. Note that all other points are configured in the same manner as the head unit 2 in the above embodiment.

  The apparatus control unit 8 includes first discharge data Sd1 including ink discharge information for each nozzle 21 of the first head unit 6A, and second discharge data Sd2 including ink discharge information for each nozzle 21 of the second head unit 6B. Then, the signals are output to the first head unit 6A and the second head unit 6B via the head drive control unit 7, respectively. However, the first ejection data Sd1 and the second ejection data Sd2 are both transferred in synchronization with the common clock signal Sc and latched with the common latch signal S1. In addition, all other points are configured in the same manner as the apparatus control unit 4 in the above embodiment.

  The head drive control unit 7 includes a waveform selection signal generation unit 74 and drive waveform selection means 75.

The waveform selection signal generation unit 74 includes a first waveform selection signal generation unit 74A and a second waveform selection signal generation unit 74B. Each of the first and second waveform selection signal generation units 74A and 74B is configured in substantially the same manner as the waveform selection signal generation unit 34 in the above embodiment, but differs in the following points.
First, the first waveform selection signal generation unit 74A and the second waveform selection signal generation unit 74B receive the clock signal Sc and the latch signal Sl in common, as well as the first ejection data Sd1 and the second ejection data Sd2. And are input to each. The first waveform selection signal generation unit 74A and the second waveform selection signal generation unit 74B are based on the first ejection data Sd1 and the second ejection data Sd2 instead of the clock signal Sc in the above embodiment. The first waveform selection signal Sk1 and the second waveform selection signal Sk2 are output to the drive waveform selection means 75. Here, the first and second waveform selection signals Sk1 and Sk2 are signals having the same properties as the waveform selection signal Sk in the above embodiment. In addition, the first waveform selection signal generation unit 74A and the second waveform selection signal generation unit 74B receive the first ejection data Sd1 and the second ejection data Sd2, and the clock signal Sc and the first clock signal Sc1. The second clock signal Sc2 is used to output the latch signal S1 to the first head unit 6A and the second head unit 6B as the first latch signal S11 and the second latch signal S12. However, the first clock signal Sc1 and the second clock signal Sc2 are always transmitted to the first head unit 6A and the second head unit 6B regardless of whether the first ejection data Sd1 and the second ejection data Sd2 are input. It may be output.

  The first waveform selection signal generation unit 74A and the second waveform selection signal generation unit 74B have first timer means 741A and second timer means 741B, respectively. These first and second timer means 741A and 741B are both configured similarly to the timer means 341 in the above embodiment.

  The drive waveform selection means 75 includes first drive waveform selection means 75A and second drive waveform selection means 75B. The first drive waveform selection means 75A and the second drive waveform selection means 75B are based on the first waveform selection signal Sk1 and the second waveform selection signal Sk2 input from the waveform selection signal generation unit 74, and the first drive waveform Sw1. And the second drive waveform Sw2 are output to the first head unit 6A and the second head unit 6B, respectively. In other respects, the first and second drive waveform selection means 75A and 75B are both configured in the same manner as the drive waveform selection means 35 in the above embodiment.

  Next, the operation of the ink jet recording apparatus 5 in this modification will be described with reference to the timing chart of FIG.

  First, when the ink jet recording apparatus 5 is powered on, the first waveform selection signal generation unit 74A and the second waveform selection signal generation unit 74B both serve as the first waveform selection signal Sk1 and the second waveform selection signal Sk2. The second waveform selection signal Skb is output to the first drive waveform selection means 75A and the second drive waveform selection means 75B. The first drive waveform selection means 75A and the second drive waveform selection means 75B both generate the non-ejection waveform Swb as the first drive waveform Sw1 and the second drive waveform Sw2 based on the input second waveform selection signal Skb. Output to the first head unit 6A and the second head unit 6B. In the first head portion 6A and the second head portion 6B, the ink in the nozzles 21 of both head portions is swung to the extent that the non-ejection waveform Swb is not ejected, so that the ink is prevented from drying.

  Next, when the first ejection data Sd1 is output from the apparatus control unit 8 and input to the first waveform selection signal generation unit 74A, the first waveform selection signal generation unit 74A drives the first waveform selection signal Ska to the first drive. In addition to switching to output to the waveform selection means 75A, the clock signal Sc is output as the first clock signal Sc1 and the latch signal S1 is output as the first latch signal S11 to the first head unit 6A. The first ejection data Sd1 starts to be transferred to the first head portion 6A in synchronization with the first clock signal Sc1, and when the first data bundle is transferred to the first head portion 6A, this data bundle is transferred to the first latch signal Sl1. Is latched by. Then, the first drive waveform selection means 75A outputs the ejection waveform Swa as the first drive waveform Sw1 to the first head unit 6A based on the first waveform selection signal Ska. The first head section 6A ejects ink droplets from the nozzles 21 in accordance with the transferred first ejection data Sd1 using the ejection waveform Swa.

  On the other hand, the second waveform selection signal generation unit 74B continues to output the second waveform selection signal Skb to the second drive waveform selection means 75B since the second ejection data Sd2 is not output from the device control unit 8. No signal is output as the second clock signal Sc2 and the second latch signal Sl2 to the second head unit 6B. As a result, the ink in the nozzles 21 continues to be swung in the second head portion 6B.

  As described above, according to the ink jet recording apparatus 5 of the present modification, the first discharge data Sd1 and the second discharge data Sd2 input to the first head unit 6A and the second head unit 6B, respectively, Since the first waveform selection signal Sk1 and the second waveform selection signal Sk2 are respectively switched, even if the clock signal Sc and the latch signal Sl are used in common, the second ejection data Sd2 is not input to the second head unit 6B. The ink in the nozzle 21 can be continuously swung. Therefore, in an apparatus including a plurality of head units, it is possible to prevent the ink of the head unit from which ejection data is not input from being dried.

  In addition, this invention is not limited to the said embodiment and its modification, Of course, it can change suitably.

It is a control block diagram of the inkjet recording device in an embodiment. (A) It is a figure which shows the waveform example of a discharge waveform, (b) It is a figure which shows the waveform example of a non-discharge waveform. 6 is a timing chart showing switching of drive waveforms in the ink jet recording apparatus according to the embodiment. (A) It is a timing chart which shows the example of transfer of the signal in connection with transfer of the discharge data in the inkjet recording device of embodiment, (b) It is the figure which expanded the waveform 1 period. It is a control block diagram of the inkjet recording device in a modification. It is a timing chart which shows switching of the drive waveform in the inkjet recording device of a modification. It is a timing chart which shows switching of the drive waveform in the conventional inkjet recording device.

Explanation of symbols

1, 5 Inkjet recording apparatus 2, 6A, 6B Head unit 21 Nozzle 31 Discharge waveform generation unit 32 Non-discharge waveform generation unit 33 Non-discharge timing generation units 34, 74A, 74B Waveform selection signal generation units 35, 75A, 75B Drive waveform selection Means 41 Switching time changing unit 42 Non-ejection interval changing unit Sc, Sc1, Sc2 Clock signal (transfer synchronization signal)
Sd, Sd1, Sd2 Discharge data Sf Discharge start signal Ska First waveform selection signal Skb Second waveform selection signals Sl, Sl1, Sl2 Latch signals Sw, Sw1, Sw2 Drive waveform Swa Discharge waveform Swb Non-discharge waveform Ti Non-discharge time Interval Ts Non-discharge switching time

Claims (6)

An inkjet recording apparatus that forms an image by discharging ink from a plurality of nozzles,
A drive waveform indicating the type of drive to be performed by the nozzle having the nozzle, discharge data including ink discharge information for each nozzle, a synchronization signal for transferring the discharge data, and completion of transfer of the discharge data A head unit that performs a predetermined drive on the nozzle by receiving a latch signal;
An ejection waveform generation unit that generates an ejection waveform for ejecting ink from the nozzle as one type of the drive waveform;
A non-ejection waveform generator for generating a non-ejection waveform for causing ink to oscillate in the nozzle as one type of the driving waveform;
Waveform selection for outputting a first waveform selection signal for selecting the ejection waveform as the drive waveform based on a predetermined type of signal input to the head unit in relation to the transfer of the ejection data to the head unit A signal generator;
Drive waveform selection means for selecting the ejection waveform as the drive waveform based on the first waveform selection signal and outputting the drive waveform to the head unit;
With
The waveform selection signal generation unit outputs the first waveform selection signal when the predetermined type of signal is input to the waveform selection signal generation unit when the non-ejection waveform is selected as the drive waveform. An ink jet recording apparatus.   The inkjet recording apparatus according to claim 1, wherein the predetermined type of signal is any one of the ejection data, the transfer synchronization signal, and the latch signal.   The inkjet recording apparatus according to claim 2, wherein the predetermined type of signal is the ejection data. When the waveform selection signal generation unit does not input at least one of a discharge start signal, which is a start signal of the discharge waveform, and the latch signal for the head unit to the discharge waveform generation unit for a predetermined time, the drive waveform A second waveform selection signal for selecting the non-ejection waveform as
The drive waveform selection unit selects the non-ejection waveform as the drive waveform based on the second waveform selection signal, and outputs the drive waveform to the head unit. The ink jet recording apparatus according to any one of claims.   The inkjet recording apparatus according to claim 4, further comprising a switching time changing unit that changes the predetermined time. A non-ejection interval changing unit for changing a time interval at which the non-ejection waveform is output;
6. The inkjet recording apparatus according to claim 1, further comprising: a non-ejection timing generation unit that generates a signal at the time interval and outputs the signal to the non-ejection waveform generation unit.

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