JP5206374B2 - Recording head driving method, recording head, and inkjet recording apparatus - Google Patents

Description

  The present invention relates to a recording head driving method, a recording head, and an ink jet recording apparatus, and more particularly to a recording head driving method, a recording head, and an ink jet recording apparatus capable of multiplying a data transfer clock and realizing high speed recording.

  Provided on one end of the recording head as an image recording apparatus capable of recording images not only on ordinary recording media such as paper and fabrics but also on recording media with poor ink absorption such as resin films and metals. An ink jet recording apparatus for recording an image by ejecting ink from a plurality of nozzles to land on a recording medium has been developed, and the technology is currently applied in various technical fields.

  In such an ink jet recording apparatus 100, as shown in FIG. 12, when image data to be recorded on a recording medium is normally transmitted from a host computer or the like (not shown), a computer attached to the ink jet recording apparatus 100 or The image data is temporarily stored in the image storage unit 102 such as a memory. Then, under the control of the control unit 101, the image processing unit 103 converts the image data into a recording head arrangement.

  When the data d1, d2,... Converted into the arrangement of the recording heads 105 is transmitted from the image processing unit 103, each nozzle of the recording head 105 is based on each data d1, d2,. Are generated and output to the nozzles of the recording head 105, and the piezo elements of the nozzles are driven in accordance with the nozzle drive signals D1, D2,. Ink is discharged from each.

  At that time, as shown in FIG. 13, when the data d 1, d 2,... For each nozzle 109 of the recording head 105 is serially transferred from the image processing unit 103 in synchronization with the clock, The data d1, d2,... Are temporarily stored in the shift register 106 once. When the data d1, d2,..., Dn corresponding to all the nozzles 109 of the recording head 105 are accumulated in the shift register 106, the data d1, d2,. Is output to the unit 107.

  When the shift register 106 outputs data d1, d2,... To the data register unit 107 and becomes empty, each data for ejecting ink from each nozzle 109 of the recording head 105 is transferred to the shift register 106 at the next ejection timing. Are sequentially transmitted and stored.

  When a data latch signal L is input to the data register unit 107, data d1, d2,... Stored in the shift register 106 are fetched at that timing, and processing such as changing the order of each data is performed. It is appropriately performed as necessary. In addition, when the ejection timing signal T is transmitted to the nozzle driving unit 108, the data d1, d2,... Taken into the data register unit 107 are simultaneously nozzled from the data register unit 107 to the nozzle driving unit 108 at that timing. It is output to the drive unit 108.

  The nozzle drive unit 108 generates nozzle drive signals D1, D2,... Based on the data d1, d2,... And outputs them to the respective nozzles 109. The piezo elements of the nozzles 109 are deformed according to the nozzle drive signals D. Ink is ejected from each nozzle 109.

  As shown in FIG. 14, the nozzle portion of the recording head 105 is partitioned by a side wall 112 provided with a piezo element 111, behind each nozzle 109, that is, inside the recording head 105 connected to each nozzle 109. Each channel 110 is provided. The nozzle driving unit 108 generates a nozzle driving signal D having a driving waveform as shown in FIG. 15 based on the data d, and applies the nozzle driving signal D to the piezo elements 111 of each channel 110.

When the drive waveform of the nozzle drive signal D rises from the reference potential V ₀ to the high potential V ₊ , the piezo element 111 curves the side wall 112 outward so as to expand the volume of the channel 110 as shown in FIG. When the drive waveform of the nozzle drive signal D decreases from the high potential V ₊ to the low potential V ₋ , the side wall 112 is now bent inward so as to reduce the volume of the channel 110 as shown in FIG. The ink in the channel 110 is pressed. Thereby, ink is ejected from each nozzle 109.

  As can be seen from the deformation of the piezo element 111 in the nozzle portion of the recording head 105 shown in FIGS. 14, 16 </ b> A, and 16 </ b> B, such a type of recording head 105 has nozzles that eject ink. When the channel 110a of 109a is enlarged, the channel 110b of the nozzle 109b adjacent to it is reduced, and when the channel 110a is reduced, the channel 110b has to be enlarged. Therefore, ink cannot be ejected simultaneously from the adjacent nozzles 109a and 109b.

  Therefore, as shown in FIG. 17, for example, every two nozzles 109 are connected by wiring, and each A-phase, B-phase, and C-phase print pulse is applied every cycle, and the print pulses are applied. By configuring the nozzle 109 to receive the nozzle driving signals D1, D2,... Output from the nozzle driving unit 108 only for a period, for example, to sequentially eject ink from every two nozzles 109, all. Ink can be ejected from the nozzle 109 (see Patent Documents 1 and 2, etc.).

  However, in this case, it is not possible to continuously eject ink from one nozzle 109, or after the channel 110 of the nozzle 109 that ejected ink expands and then waits for it to shrink, Due to restrictions such as the inability to enlarge or reduce the channel 110, the number of ink ejections from one nozzle 109 can be increased only to a certain level.

  In recent years, there has been an increasing demand for an ink jet recording apparatus to increase the number of times of ink discharge per unit time. However, in the case of such multi-phase (three-phase) driving, it is difficult to meet the demand. There was a problem.

  On the other hand, the recording head 105 of the type described above can be configured such that ink is ejected from only every other nozzle 109 and ink is not ejected from the nozzles 109 in the meantime. In this case, every other nozzle (so-called invalid nozzle) that does not eject ink also exists. In addition, no nozzles may be formed in the invalid nozzle channel 110 in the first place.

  With this configuration, the channel 110 portion of the ineffective nozzle functions as a buffer, and the nozzle 109 that ejects ink is related to the movement of the side wall 112 of the channel 110 of the other nozzle 109 that ejects ink. In addition, the side wall 112 of the channel 110 can be enlarged / reduced only for the ejection of its own ink, and the ink ejection can be independently performed for the nozzles 109 that eject the ink.

  Since ink can be continuously ejected from one nozzle 109, unlike the case of multi-phase driving, the number of ink ejections per unit time from one nozzle 109 can be increased. It becomes possible.

  As described above, since there is a recording head 105 that can be driven at high speed by ejecting ink from every other nozzle 109 and independently driving the nozzle 109, data transfer to such a recording head 105 is possible. Also, it is necessary to configure so as to support high-speed driving.

As shown in FIG. 12, when data d1, d2,... Are serially transferred from the image processing unit 103 to the head driving unit 104, the data d1, d2,. The data is transferred at a prescribed transfer timing. At this time, as described in Patent Document 3, the data transfer clock cl is multiplied, and the data d1, d2,... Are transferred based on the multiplied data transfer clock. If configured to do so, it is considered that the data d1, d2,... Can be serially transferred to the head driving unit 104 at a higher speed, and the number of ink ejections per unit time from one nozzle 109 is further increased. Is expected to be.
JP 2001-301163 A JP 2004-181789 A JP 2002-370361 A

  However, when the recording head 105 of the type described above is configured to eject ink from every other nozzle 109, it is possible to eject even invalid nozzles simply by multiplying the data transfer clock cl. Since the data to be performed is input, the ink ejection amount from every other nozzle 109 becomes abnormal (that is, the ink is not ejected correctly), or no ink is ejected from the nozzle 109 at all.

  As described above, since there is a recording head 105 that can be driven at high speed by ejecting ink from every other nozzle 109 and independently driving the nozzle 109, data transfer to such a recording head 105 is possible. However, in order to discharge the nozzle 109 of the recording head 105 of the above type independently, extra data that is not discharged to the invalid nozzle is also necessary. Since the data transfer amount increases and the data transfer amount increases by an amount corresponding to the invalid nozzle, if the data transfer clock cl is increased to increase the data transfer rate, the image processing unit 103 Noise emission to the head drive unit 104 increases.

  Further, if an expensive cable capable of transferring data at high speed is installed over a long distance from the image processing unit 103 to the head driving unit 104, the installation of the cable is expensive, and the configuration of the image processing unit 103 is not shown in the memory. There is a problem that the cost of the system is increased, for example, the area must be enlarged.

  The present invention has been made in view of the above-described problems, and can normally eject ink from the nozzles of the recording head, and can cope with an increase in the number of ink ejections per unit time from one nozzle. It is an object of the present invention to provide a recording head driving method, a recording head, and an ink jet recording apparatus that can perform the above operation.

In order to solve the above problem, the recording head driving method of the present invention includes:
A recording head driving method for driving a recording head of an inkjet recording apparatus having a plurality of nozzles,
A clock for multiplying a data transfer clock for defining a transfer timing for transferring data corresponding to each of the nozzles ejecting ink set at a predetermined number of the plurality of nozzles by a number obtained by adding 1 to the predetermined number. Multiplication step;
Wherein each data, fixed data, meaning not to eject the predetermined number of ink is set corresponding to the multiplication factor of the multiplication data transfer clock imparted respectively, to the multiplied data transfer clock A fixed data assignment step to be assigned;
An input step of inputting each of the data to which the fixed data assigned to the multiplied data transfer clock is assigned to each register of a data register unit;
An output step of outputting each data to which the fixed data is given from each register of the data register unit to a nozzle driving unit;
An ejection step of ejecting ink from each nozzle ejecting ink based on each nozzle drive signal generated based on each data to which the fixed data is given by the nozzle drive unit;
It is characterized by having.

The recording head of the present invention is
A recording head of an ink jet recording apparatus having a plurality of nozzles,
A clock for multiplying a data transfer clock for defining a transfer timing for transferring data corresponding to each of the nozzles ejecting ink set at a predetermined number of the plurality of nozzles by a number obtained by adding 1 to the predetermined number. A multiplier,
Wherein each data, fixed data, meaning not to eject the predetermined number of ink is set corresponding to the multiplication factor of the multiplication data transfer clock imparted respectively, to the multiplied data transfer clock A fixed data assignment unit to be assigned;
A data register unit for temporarily storing each data to which the fixed data assigned to the multiplied data transfer clock is assigned;
It said data register unit said nozzle drive unit for discharging driving each nozzle the fixed data output from each register to eject ink by generating each nozzle drive signals for the respective nozzles based on the respective data granted for When,
A discharge control unit that transmits a data latch signal to the data register unit and causes the data register unit to capture the data to which the fixed data is added, and that transmits a discharge timing signal to the nozzle drive unit;
With
Each of the nozzles and each register of the data register unit are electrically connected to each other through wiring through the nozzle driving unit.

  Furthermore, an ink jet recording apparatus according to the present invention includes the recording head according to the present invention.

  According to the recording head driving method, the recording head, and the ink jet recording apparatus of the present invention, each data generated by multiplying the data transfer clock and giving fixed data to each data with respect to the multiplied data transfer clock. Configured to allocate data. For this reason, it becomes possible to eject ink from every other nozzle of the recording head and drive the nozzles independently, corresponding to high-speed driving, that is, speeding up the number of ink ejections per unit time from one nozzle. It becomes possible.

  In addition, since fixed data (for example, 0) is appropriately given as data corresponding to the nozzle that does not eject ink, a nozzle drive signal having a value of, for example, 0 is accurately applied to the nozzle that does not eject ink. For this reason, noise emission from the image processing unit to the head drive unit is blocked, so that ink is not reliably ejected from nozzles that do not eject ink, and ink is ejected normally from nozzles that should eject ink. It becomes possible. Furthermore, since it is not necessary to install an expensive cable capable of transferring data at high speed over a long distance from the image processing unit to the head driving unit, it is possible to prevent an increase in the cost of the ink jet recording apparatus. In addition, the above-described effect can be obtained even when a low-speed wiring is used as compared with the conventional cable capable of high-speed transfer without using an expensive cable capable of performing high-speed data transfer. Is possible.

  Hereinafter, embodiments of a recording head driving method, a recording head, and an ink jet recording apparatus according to the present invention will be described with reference to the drawings. First, the configuration of the inkjet recording apparatus and the recording head of the present invention to which the recording head driving method according to the present embodiment is applied will be described.

  As shown in FIG. 1, the ink jet recording apparatus 1 according to the present embodiment mainly includes a transport unit 2, a scan unit 3, an ink rack 4, and a computer 5.

  An endless conveyance belt 21 for conveying a recording medium (not shown) from the back side (the lower surface side in the drawing) and conveying it in the sub-scanning direction Y indicated by an arrow Y in the drawing is arranged on the upper portion of the conveyance unit 2. It is installed. Instead of the conveyor belt 21, a plate-like platen can be used. In the present embodiment, the transport unit 2 and the scan unit 3 are formed as separate bodies, but may be formed integrally.

  As described above, the recording medium is not particularly limited, and may be a resin film, metal, or the like in addition to paper and fabric.

  The scanning unit 3 is disposed above the conveying belt 21 of the conveying unit 2, but behind the scanning unit 3, each color ink (liquid) supplied to a plurality of recording heads 8 to be described later is stored. An ink rack 4 including an ink tank 41 is disposed. Ink is supplied from each ink tank 41 to each recording head 8 via a pipe 15 described later.

  Below the scan unit 3, a computer 5 configured by connecting a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like (not shown) to the bus is arranged. The above-described data d1, d2,..., Electrical signals, etc. are transmitted from the computer 5 to the recording heads 8 via wirings 11 described later.

  In the present embodiment, the computer 5 is configured to function also as the control unit 101, the image storage unit 102, and the image processing unit 103 in FIG. That is, a storage device (not shown) such as an HDD (Hard Disk Drive) is connected to the computer 5 as an image storage unit. The computer 5 receives image data to be recorded on a recording medium from a host computer (not shown). When transmitted, the image data is temporarily stored in the storage device.

  Further, the computer 5 generates image data d1, d2,... For the nozzles 81 of the recording head 8 by converting the transmitted image data into the arrangement of the recording heads 8 as an image processing unit. The data d1, d2,... Are serially transferred to the head drive unit 83 of the recording head 8, which will be described later.

  Further, the computer 5 controls each part of the inkjet recording apparatus 1 as a control unit, and serially transfers data d1, d2,... From the computer 5 as an image processing unit to the head driving unit 83 of the recording head 8. The data transfer clock cl that defines the transfer timing is set and output.

  FIG. 2 is a diagram illustrating a main part inside the scan unit. Note that there is actually a head moisturizing unit that caps the nozzle surface 81a of the recording head 8 and moisturizes it while the operation of the inkjet recording apparatus 1 is stopped, on the left pedestal portion of the scanning unit 3 in the figure. There is a maintenance unit in which a head cleaning mechanism and the like for performing maintenance of the recording head 8 are disposed on the pedestal portion, but the illustration is omitted in FIG.

  Inside the scan unit 3, a rod-shaped carriage rail 6 is arranged so as to extend in the main scanning direction X indicated by an arrow X in the figure perpendicular to the sub-scanning direction Y. A substantially housing-like carriage 7 is supported along the carriage rail 6 so as to be reciprocally movable in the main scanning direction X.

  As shown in FIG. 3, the carriage 7 has a nozzle surface 81a on which a plurality of nozzles 81 for discharging ink of each color such as yellow (Y), magenta (M), cyan (C), and black (K) are arranged. A plurality of main body portions 82 of the recording heads 8 are mounted. The inks of the respective colors are applied from the nozzles 81 of the main body portions 82 of the recording heads 8 to the recording medium S on the conveying belt 21 of the conveying unit 2 described above. Drops are ejected.

  Further, as shown in FIG. 4, the upper end portion of the carriage 7 is flexibly deformed and follows the movement of the carriage 7 reciprocating in the main scanning direction X to protect the wiring 11 and the pipe 15 accommodated therein. The cable bear 9 is connected.

  As described above, the pipe 15 is for supplying ink from each ink tank 41 to the main body 82 of each recording head 8. In the present embodiment, the ink supply pipe 13 is connected via the joint 14. It is connected to. Although not shown, the ink supply pipes 13 are connected to the main body portion 82 of the predetermined recording head 8, and predetermined color inks are supplied to the main body portion 82 of the recording head 8 via the pipe 15 and the ink supply pipe 13. It comes to be supplied.

  Further, in the present embodiment, each pipe 15 is accommodated in a resin tube 16 for each predetermined number, and the pipe 15 and the wiring 11 are partitioned in the cable bear 9 so that they do not rub against each other. A partition wall 18 is provided. Further, the wiring 11 is not a cable that can transfer data at a high speed, but a cable that transfers data at a low speed compared to the above-described cable that can transfer data at a high speed.

  At the upper end of the carriage 7, a head driving unit 83 of each recording head 8 for controlling the ejection of ink droplets from each nozzle 81 of the main body 82 of each recording head 8 is arranged on the substrate. The data d1, d2,..., The data transfer clock cl, etc. transmitted from the computer 5 are transmitted to each head drive unit 83 via the wiring 11, the connector 12, and the like. In FIG. 4, illustration of electronic components such as an IC in the head driving unit 83 of the recording head 8 is omitted.

  As shown in FIG. 5, the recording head 8 according to this embodiment includes a main body 82 and a head driving unit 83 of the recording head 8, and the head driving unit 83 includes those shown in FIG. 13. In addition to the similar shift register 84, data register unit 85, and nozzle drive unit 86, a clock multiplication unit 87, a fixed data applying unit 88, and a discharge control unit 89 are provided.

  In the present embodiment, the registers of the shift register 84, the registers of the data register 85, and the nozzles 81 of the main body 82 of the recording head 8 are electrically connected to each other by wiring via the nozzle driving unit 86. ing.

  Hereinafter, the configuration of each part in the head driving unit 83 of the recording head 8 will be described, and the recording head driving method of the recording head 8 according to the present embodiment will be described based on the flowchart shown in FIG.

  First, when the user instructs the computer 5 to start recording an image on the recording medium S by the ink jet recording apparatus 1, a recording start signal Ts is transmitted from the computer 5 to the head drive unit 83 of the recording head 8, This is input to the ejection control unit 89 of the head drive unit 83. When the recording start signal Ts is input, the ejection control unit 89 starts monitoring the operation of the fixed data adding unit 88.

  As described above, when the data transfer clock cl is transmitted from the computer 5 of the inkjet recording apparatus 1 to the head drive unit 83 of the recording head 8 via the wiring 11, the data transfer clock cl is sent to the clock multiplication unit 87. Entered. As described above, the data transfer clock cl is a clock that defines transfer timing for transferring data corresponding to each of the plurality of nozzles 81 of the storage head 8.

  When the data transfer clock cl is input, the clock multiplier 87 multiplies the data transfer clock cl (clock multiplication step S1). In the present embodiment, the clock multiplier 87 includes a PLL (Phase-locked loop) frequency synthesizer and the like, and the clock multiplier 87 receives the input data transfer clock cl as shown in FIG. , The signal frequency is doubled, and the multiplied data transfer clock CL as shown in FIG. 7B is output to the fixed data adding unit 88 and the shift register 84. Yes.

  The fixed data giving unit 88 receives the multiplied data transfer clock CL transmitted from the clock multiplying unit 87 and the data d1, d2,... Transmitted from the computer 5. . Then, the fixed data providing unit 88 provides each data d1, d2,... With a fixed number of fixed data set corresponding to the multiplied number of the multiplied data transfer clock CL, and the multiplied data transfer clock. The data is assigned to CL (fixed data provision step S2).

  Specifically, in the present embodiment, the fixed data is set to 0, which means that ink is not ejected, and the fixed data providing unit 88 is a multiplication number of the multiplied data transfer clock CL (above-mentioned In this case, the number of fixed data corresponding to 2) is set to 1 (= 2-1) obtained by subtracting 1 from the multiplication number (2).

  That is, in the above case, 0 is added to each data d, so that the fixed data adding unit 88 converts the input data d1, d2, d3,... Into the data d1, 0, d2 , 0, d3, 0,... Then, as shown in FIG. 8, each data to which fixed data (that is, 0) is assigned is assigned to the multiplied data transfer clock CL.

  Then, each data assigned to the multiplied data transfer clock LC and the fixed data d1, 0, d2, 0, d3, 0,... Are output from the fixed data adding unit 88 and serially transferred to the clock multiplication unit 87. Are temporarily stored in the shift register 84 once in synchronization with the multiplied data transfer clock LC output from the.

  When the data d1, 0, d2, 0,... Corresponding to all the nozzles 81 of the main body 83 of the recording head 8 are accumulated in the shift register 84, the data d1, 0, d2, 0,. Is output from the shift register 84 to the data register unit 85 and input to each register of the data register unit 85 (input step S3).

  In the data register unit 85, the input data d1, 0, d2, 0,... Are temporarily stored. At this time, processing such as changing the order of the data is required. It is performed accordingly. When the shift register 84 outputs data d1, 0, d2, 0,... To the data register unit 85 and becomes empty, the shift register 84 ejects ink from each nozzle 81 of the recording head 8 at the next ejection timing. The data d1, 0, d2, 0,... Are sequentially transmitted and accumulated.

  As described above, the ejection control unit 89 monitors the operation of the fixed data providing unit 88, and the fixed data providing unit 88 sets each data d1, 0, d2, corresponding to all the nozzles 81 of the main body 83 of the recording head 8. When it is confirmed that the output of 0,... Has been completed, the data latch signal L is transmitted to the data register unit 85 at the timing at which the data d1, 0, d2, 0,. It has become.

  When receiving the data latch signal L, the data register unit 85 takes in the data d1, 0, d2, 0,... To which the fixed data 0 stored in the shift register 84 is added at that timing. And the process of changing the order of each data as needed is performed.

  Further, the ejection control unit 89 transmits the ejection timing signal T to the nozzle driving unit 86 at an appropriate timing after transmitting the data latch signal L to the data register unit 85.

  When receiving the ejection timing signal T, the nozzle driving unit 86 transmits the data d1, 0, d2, 0,... Taken in by the data register unit 85 all at once, that is, in parallel.

When each data d1, 0, d2, 0,... Is input, the nozzle driving unit 86 receives nozzle driving signals D1, 0, D2, 0, having a driving waveform as shown in FIG. ... is generated. In this case, the nozzle drive signal 0 is a waveform in which both V ₊ and V ₋ are equal to V ₀ in the drive waveform shown in FIG. 15, that is, a constant value V ₀ (usually set to 0 [V]). A drive waveform whose value does not vary. Even when a constant value V ₀ is applied, the piezo element of the nozzle 81 is not deformed at all, so that no ink is ejected from the nozzle 81.

  And the nozzle drive part 86 applies the nozzle drive signal D1, 0, D2, 0,... Generated to each piezoelectric element (not shown in FIG. 5) of each nozzle 81 of the main body part 82 of the recording head 8, Each nozzle 81 is driven to discharge (discharge step S5).

In the nozzle 81 to which the nozzle drive signals D1, D2,... Generated based on the respective data d1, d2,..., Which are not fixed data, are applied, the piezo element is shown in accordance with the drive waveform of the nozzle drive signal D shown in FIG. 16 (A) and 16 (B), the ink is ejected from the nozzle 81 in accordance with the nozzle drive signals D1, D2,. However, as described above, in the nozzle 81 to which the nozzle driving signal 0 generated based on each fixed data (0 in the present embodiment), that is, the nozzle driving signal having the constant value V ₀ is applied, the piezo element. Is not deformed, and ink is not ejected from the nozzle 81.

  Therefore, in the recording head 8 to which the nozzle drive signals D1, 0, D2, 0,... Are applied, the nozzles 81 that eject ink and the nozzles 81 that do not eject ink are alternately arranged. Ink is ejected.

  The above process is repeated until a predetermined image is formed on the recording medium S or until an instruction to stop image recording is input by the user.

  Next, operations of the recording head driving method, the recording head 8, and the inkjet recording apparatus 1 according to the present embodiment will be described.

  As described above, when ink is ejected simultaneously from the nozzles 81 of the recording head 8 of the present embodiment, that is, at the same ejection timing, the nozzle portions of the recording head shown in FIGS. 14 and 16A and 16B are used. As can be seen from the deformation of the piezo element, ink cannot be ejected simultaneously from the adjacent nozzles 81, so that ink is ejected from at least every other nozzle 81.

When a significant non-zero nozzle drive signal D is applied to each nozzle 81 that does not eject ink in the portion between the nozzles 81 that eject ink, that is, the drive waveform of the nozzle drive signal D shown in FIG. When a waveform having a value of V ₊ or V _{− other} than V ₀ is applied to the nozzle 81, the piezoelectric element of the nozzle 81 tends to deform accordingly. For this reason, the normal deformation of the piezo element in the nozzle 81 that ejects ink adjacent thereto is hindered, and an ejection abnormality from the nozzle 81 that should eject ink occurs.

Therefore, in order to apply a nozzle drive signal having a value of ₀ , that is, a nozzle drive signal having a constant value V ₀ , to each nozzle 81 that does not eject ink, each data d1, d2 that is a basis for generating the nozzle drive signal ,..., It is necessary to give fixed data 0 to the portion corresponding to each nozzle 81 that does not eject ink.

  At this time, as shown in FIG. 9, if each data d1, 0, d2, 0,... To which the fixed data 0 is assigned is assigned to the data transfer clock cl and serially transferred to the head drive unit 83 of the recording head 8, Ink can be ejected from every other nozzle 81. However, if each data d1, 0, d2, 0,... Is assigned to the data transfer clock cl without multiplying the data transfer clock cl, as shown in FIG. Each of the transferred data d1, 0, d2, 0,... Is redundant, and the number of ink ejections from one nozzle 81 per unit time cannot be increased.

  Therefore, by multiplying the data transfer clock cl and assigning the data d1, d2,... To the multiplied data transfer clock CL, it is expected that the number of ink ejections from one nozzle 81 per unit time will be increased. However, as described above, simply multiplying the data transfer clock cl does not speed up the number of ink ejections per unit time from one nozzle 81, causing abnormal ejection, or no ink from the nozzles 81 at all. The phenomenon that it is not discharged occurs.

  As shown in FIG. 10, when each data d1, d2,... Is assigned to the multiplied data transfer clock CL, each data d1, d2,. , D2, d2, d3, d3,... Are assigned so that two pieces of data having the same value are consecutive.

  When such data d1, d1, d2, d2, d3, d3,... Is assigned to the multiplied data transfer clock CL and serially transferred to the head drive unit 83 of the recording head 8, each nozzle that does not eject ink A significant non-zero nozzle drive signal D is applied to 81. Therefore, in the same manner as described above, the piezo element that should not be deformed tends to be deformed, and the normal deformation of the piezo element in the nozzle 81 that ejects the adjacent ink is obstructed, and the ejection from the nozzle 81 that should eject the ink. Abnormality will occur.

  On the other hand, each data generated by multiplying the data transfer clock cl and adding the fixed data 0 to each data d1, d2,... With respect to the multiplied data transfer clock CL as in the present embodiment. If d1, 0, d2, 0,... are assigned (see FIG. 8), as shown in FIG. 9, the data d1, 0, each of which the fixed data 0 is added to the non-multiplied data transfer clock cl. Compared with the case where d2, 0,... are assigned and serially transferred to the head drive unit 83 of the recording head 8, the number of ink ejections from one nozzle 81 can be increased at least twice as fast. Become.

  In addition, since the fixed data 0 is accurately given as data corresponding to the nozzle 81 that does not eject ink, a nozzle drive signal having a value of 0 is accurately applied to the nozzle 81 that does not eject ink. Therefore, as shown in FIG. 10, it is possible to accurately prevent the occurrence of abnormal discharge from the nozzle 81 that should eject ink by applying a significant non-zero nozzle drive signal D to the nozzle 81 that does not eject ink. It becomes possible to do.

  If ink is not supplied to the channel of the nozzle 81 that does not eject ink (see the channel 110 in FIG. 14 or the like), the ink is prevented from being accidentally ejected from the nozzle 81. It becomes possible. In addition, the presence of an empty channel allows the piezo elements of the nozzle 81 that ejects ink to be deformed independently of each other without being affected by the deformation of other piezo elements. Performance is improved.

  Further, the operation as in the above-described embodiment is, for example, each data as shown in FIG. 10 in which each data d1, d2,... Not assigned fixed data 0 is assigned to the multiplied data transfer clock CL. , d1, d2, d2, d3, d3,... are serially transferred to the head driving unit 83 of the recording head 8, and the ink is connected to the nozzle driving unit 86 and each nozzle 81 as shown in FIG. This can also be realized by grounding each wiring of each nozzle 81 that does not discharge.

  In this case, nozzle drive signals D1, D1, D2, D2, D3, D3,... Are output from the nozzle drive unit 86 to the nozzles 81, but the wirings of the nozzles 81 that do not eject ink are grounded. Therefore, nozzle drive signals D1, 0, D2, 0, D3, 0,... Are applied to each nozzle 81. Therefore, ink is ejected from each nozzle 81 that should eject ink in accordance with the nozzle drive signals D1, D2, D3,..., And a nozzle drive signal having a value of 0 is applied to each nozzle 81 that does not eject ink. Therefore, ink is not ejected.

  FIG. 11 shows a case where a part of each wiring connecting the nozzle driving unit 86 and each nozzle 81 is grounded, but a part of each wiring connecting the data register unit 85 and the nozzle driving unit 86, Even if a part of each wiring connecting the shift register 84 and the data register unit 85 is grounded, the same effect can be obtained.

  However, since at least the shift register 84, the data register unit 85, and the nozzle driving unit 86 of the head driving unit 83 of the recording head 8 are often provided in one IC, the configuration shown in FIG. Although it is necessary to modify the IC as shown or to provide a dedicated IC, it is practically difficult to modify the IC. Also, as shown in FIG. If provided, only a nozzle drive signal having a value of 0 is necessarily applied to the predetermined nozzle 81.

  Therefore, in such a modified IC or a dedicated IC, ink cannot be ejected from the adjacent nozzles 81 while shifting the phase by the multi-phase (three-phase) driving as described above, and the multi-phase (3 When performing (phase) driving, the IC of the head driving unit 83 of the recording head 8 must be replaced and wired, and the image recording operation becomes very complicated.

  Further, as shown in FIG. 8, each of the data generated by adding the fixed data 0 to the data d1, d2,... For the process of multiplying the data transfer clock cl or the multiplied data transfer clock CL. The process of assigning data d1, 0, d2, 0,... Can be performed by the computer 5 of the inkjet recording apparatus 1, and in this case, the same operation as in this embodiment can be performed. . However, in this case, there is a problem such as an interface between the computer 5 and the head driving unit 83 of the recording head 8, and it cannot always be configured easily.

  In this respect, if the clock multiplying unit 87, the fixed data providing unit 88, and the like are provided on the head driving unit 83 side of the recording head 8 as in the present embodiment, the computer 5 performs the same processing as in a normal case. The data transfer clock cl that is not multiplied and the data d1, d2,. Further, it is only necessary to rework the substrate of the head driving unit 83 of the recording head 8 shown in FIG. 4 and provide the clock multiplying unit 87, the fixed data providing unit 88, etc. on the substrate and rewiring. This configuration can be easily realized.

  As described above, according to the recording head driving method, the recording head 8, and the ink jet recording apparatus 1 according to the present embodiment, the data transfer clock cl is multiplied and each data is multiplied with respect to the multiplied data transfer clock CL. The data d1, 0, d2, 0,... generated by assigning the fixed data 0 to d1, d2,.

  Therefore, ink can be ejected from every other nozzle 81 of the recording head 8 and the nozzles 81 can be driven independently, and high-speed driving, that is, high-speed ink ejection per unit time from one nozzle 81 is achieved. It becomes possible to cope with the conversion.

  Moreover, since the fixed data 0 is accurately given as data corresponding to the nozzles 81 that do not eject ink, a nozzle drive signal having a value of 0 is accurately applied to the nozzles 81 that do not eject ink. Therefore, noise emission from the computer 5 serving as the image processing unit to the head driving unit 83 of the recording head 8 is blocked, and no ink is reliably ejected from the nozzles 81 that do not eject ink. The ink can be ejected normally.

  Further, since there is no need to install an expensive cable capable of high-speed data transfer over a long distance from the computer 5 as the image processing unit to the head drive unit 83 of the recording head 8, the cost of the inkjet recording apparatus 1 is increased. Can be prevented.

  In addition, the wiring 11 that connects the computer 5 that is the image processing unit and the head driving unit 83 of the recording head 8 does not use an expensive cable that can perform high-speed data transfer, and is conventionally used. As described above, it is possible to independently drive the nozzles 81 by ejecting ink from every other nozzle 81 of the recording head 8 even when using a low-speed wiring 11 compared to a cable capable of high-speed transfer. Therefore, it is possible to sufficiently cope with an increase in the number of ink ejections per unit time from one nozzle 81.

  Note that by increasing the frequency of the data transfer clock cl itself transmitted from the computer 5 to the head drive unit 83 of the recording head 8, the multiplied data transfer clock CL is also increased in frequency, and per unit time from one nozzle 81. The number of ink ejections can be increased.

  Further, in the present embodiment, the case where ink is ejected from every other nozzle 81 has been described, but in addition to this, for example, it is also possible to configure so that ink is ejected from every other nozzle 81 or the like. is there.

  For example, when ink is ejected from every second nozzle 81, the data transfer clock cl is multiplied by 3 and each data d1, d2,... Is subtracted 1 from the multiplication number (3) 2 (= 3-1) ) By giving 0 pieces of fixed data 0 and transmitting the data as d1, 0, 0, d2, 0, 0,... Ink can be ejected from the nozzles 81, and ink can not be ejected from the two nozzles 81 between them, and it can be performed at high speed.

  Furthermore, in the present embodiment, as described above, as shown in FIG. 11, a part of each wiring connecting the nozzle drive unit 86 and each nozzle 81 is not grounded, but as shown in FIG. When the nozzle 81 that does not eject ink and the nozzle drive unit 86 are connected by a wiring and the nozzle drive signal D is output from the nozzle drive unit 86, the nozzle drive signal D is applied to the nozzle 81.

  Therefore, in the case where it is desired to perform multi-phase (three-phase) driving as shown in FIG. 17 instead of ejecting ink from every other nozzle 81 as in the above-described embodiment, the structure is multi-phase. It is also possible to drive. When performing multi-phase driving, fixed data 0 is not assigned to each data d1, d2,..., And if the data transfer clock cl is multiplied in that state, the situation shown in FIG. It is necessary to return to the normal process of assigning the data d1, d2,... To the data transfer clock cl not to be performed (see FIG. 18).

  Therefore, a transfer control unit (not shown) can be provided on the substrate of the head driving unit 83 of the recording head 8 so as to be connected to the clock multiplication unit 87 and the fixed data providing unit 88 (see FIG. 5).

  Then, a signal is transmitted from the transfer control unit to the clock multiplying unit 87 and the fixed data providing unit 88, the data transfer clock cl is multiplied by the clock multiplying unit 87, and the data transfer clock CL multiplied by the fixed data providing unit 88 is generated. The clock multiplication transfer according to the above-described embodiment in which each data d1, 0, d2, 0,... To which fixed data is assigned is assigned and ink is ejected from each nozzle 81 based on each data d1, 0, d2, 0,. In order to use the mode and multi-phase driving, the clock multiplier 87 outputs the data transfer clock cl without being multiplied by the data transfer clock cl, and the fixed data adder 88 outputs the data transfer clock cl that has not been multiplied. The data d1, d2,... To which no fixed data 0 is assigned are assigned as they are (see FIG. 18), and the data d1, d2,. It can be configured to control so as to switch between the normal transfer mode to eject ink from the nozzles 81 Zui.

  Further, instead of providing the transfer control unit in the head drive unit 83 of the recording head 8, the computer 5 of the inkjet recording apparatus 1 is provided with the function so that the computer 5 switches between the clock multiplication transfer mode and the normal transfer mode. It can also be configured to control.

  With this configuration, the transfer control unit or the computer 5 switches the data transfer mode between the clock multiplication transfer mode and the normal transfer mode, and the recording head 8 or the inkjet recording apparatus 1 performs the recording according to the above embodiment. It is possible to realize both a head driving method and a method of ejecting ink from the nozzle 81 by normal multiphase (three-phase) driving.

  And, by appropriately selecting and switching the transfer mode that satisfies various conditions required for image recording such as high-speed image recording and high-definition image recording, it appropriately meets the user's requirements. Image recording can be realized.

1 is a diagram illustrating an overall configuration of an ink jet recording apparatus according to an embodiment. It is a figure showing the principal part inside the scan unit of the inkjet recording device of FIG. FIG. 3 is a diagram illustrating a configuration of a carriage portion in the scan unit of FIG. 2. FIG. 4 is a diagram illustrating a configuration of a substrate of a head driving unit of a recording head provided at an upper end portion of a carriage, a cable bear connected thereto, and the like. FIG. 2 is a block diagram illustrating a configuration of a recording head according to the present embodiment. 6 is a flowchart illustrating steps in a recording head driving method according to the embodiment. (A) It is a timing chart which shows the data transfer clock before multiplication, (B) It is a timing chart which shows the data transfer clock multiplied. It is a timing chart which shows each data to which the multiplied data transfer clock and the fixed data allocated to it were given. It is a timing chart which shows each data to which the data transfer clock which is not multiplied and the fixed data allocated to it were given. It is a timing chart which shows the multiplied data transfer clock and each data allocated to it. FIG. 6 is a diagram illustrating a configuration example in which a part of a wiring connecting a nozzle driving unit and each nozzle is grounded in the recording head of FIG. 5. 1 is a block diagram illustrating a configuration of an inkjet recording apparatus and a flow of data and the like. It is a block diagram showing a configuration of a recording head including a conventional head driving unit. FIG. 3 is a diagram illustrating a configuration of a nozzle portion of a recording head when the nozzle is viewed from the channel side, that is, the inner side. It is a figure which shows the example of the drive waveform of a nozzle drive signal. It is a figure showing the deformation | transformation method of a piezo element at the time of ejecting ink, (A) The state where the volume of the channel was expanded, (B) The state where the volume of the channel was reduced is shown. It is a figure which shows the connection state of the wiring at the time of driving a nozzle 3 phase. It is a timing chart which shows a data transfer clock and each data allocated to it.

Explanation of symbols

DESCRIPTION OF SYMBOLS 0 Fixed data 1 Inkjet recording device 5 Computer 8 Recording head 81 Nozzle 85 Data register part 86 Nozzle drive part 87 Clock multiplication part 88 Fixed data provision part 89 Discharge control part cl Data transfer clock CL Multiplied data transfer clock d, d1, d2,..., data d1, 0, d2, 0,..., each data D, D1, D2,... to which fixed data is given Nozzle drive signal L Data latch signal T Discharge timing signal

Claims (5)

A recording head driving method for driving a recording head of an inkjet recording apparatus having a plurality of nozzles,
A clock for multiplying a data transfer clock for defining a transfer timing for transferring data corresponding to each of the nozzles ejecting ink set at a predetermined number of the plurality of nozzles by a number obtained by adding 1 to the predetermined number. Multiplication step;
Wherein each data, fixed data, meaning not to eject the predetermined number of ink is set corresponding to the multiplication factor of the multiplication data transfer clock imparted respectively, to the multiplied data transfer clock A fixed data assignment step to be assigned;
An input step of inputting each of the data to which the fixed data assigned to the multiplied data transfer clock is assigned to each register of a data register unit;
An output step of outputting each data to which the fixed data is given from each register of the data register unit to a nozzle driving unit;
An ejection step of ejecting ink from each nozzle ejecting ink based on each nozzle drive signal generated based on each data to which the fixed data is given by the nozzle drive unit;
A recording head driving method comprising: A recording head of an ink jet recording apparatus having a plurality of nozzles,
A clock for multiplying a data transfer clock for defining a transfer timing for transferring data corresponding to each of the nozzles ejecting ink set at a predetermined number of the plurality of nozzles by a number obtained by adding 1 to the predetermined number. A multiplier,
Wherein each data, fixed data, meaning not to eject the predetermined number of ink is set corresponding to the multiplication factor of the multiplication data transfer clock imparted respectively, to the multiplied data transfer clock A fixed data assignment unit to be assigned;
A data register unit for temporarily storing each data to which the fixed data assigned to the multiplied data transfer clock is assigned;
It said data register unit said nozzle drive unit for discharging driving each nozzle the fixed data output from each register to eject ink by generating each nozzle drive signals for the respective nozzles based on the respective data granted for When,
A discharge control unit that transmits a data latch signal to the data register unit and causes the data register unit to capture the data to which the fixed data is added, and that transmits a discharge timing signal to the nozzle drive unit;
With
The recording head, wherein each nozzle and each register of the data register unit are electrically connected to each other through wiring through the nozzle driving unit. Further, the data transfer clock is multiplied, the data to which the fixed data is assigned is assigned to the multiplied data transfer clock, and ink is ejected based on the data to which the fixed data is assigned. A clock multiplying transfer mode in which ink is ejected from the nozzles, and a normal operation in which each data is allocated to the data transfer clock without multiplying the data transfer clock and ink is ejected from all the nozzles based on the data. The recording head according to claim 2, further comprising a transfer control unit that controls to switch the transfer mode.   An ink jet recording apparatus comprising the recording head according to claim 2. A recording head according to claim 2,
Further, the data transfer clock is multiplied, the data to which the fixed data is assigned is assigned to the multiplied data transfer clock, and ink is ejected based on the data to which the fixed data is assigned. A clock multiplying transfer mode in which ink is ejected from the nozzles, and a normal operation in which each data is allocated to the data transfer clock without multiplying the data transfer clock and ink is ejected from all the nozzles based on the data. An inkjet recording apparatus comprising: a computer that controls to switch between transfer modes.

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