JP5034591B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus using a multiphase drive recording head.

  As an image recording apparatus capable of recording an image not only on a normal base material such as paper or fabric but also on a base material with poor ink absorption such as a resin film, a nozzle provided on one end surface of the recording head is used. An ink jet recording apparatus for ejecting ink and landing on a substrate has been developed, and the technology is currently applied in various technical fields.

  For example, when the recording head is a line head type recording head, as shown in the schematic plan sectional view of FIG. There are cases where each ink channel IC provided behind the nozzle N, that is, inside the recording head H, is a so-called shared wall type in which the wall surface is shared by adjacent ink channels IC.

  In this case, the wall surface of the ink channel IC is configured to include a piezoelectric element actuator such as a piezo element, and as shown in FIG. 20B, both side surfaces are bent inward to reduce the volume in the ink channel ICv. As a result, the ink in the ink channel ICv is pushed out and ejected from the nozzle Nv.

  However, since the volume of the adjacent ink channels ICv-1 and ICv + 1 is increased, it is not possible to eject ink from the nozzles Nv-1 and N + 1 simultaneously with the ejection from the nozzle Nv. Therefore, in the above-described conventional ink jet recording apparatus, for example, a recording method in which every other nozzle is driven and ink is simultaneously ejected from every other nozzle may be employed. However, for example, when every other nozzle is driven, the ejection efficiency deteriorates, and the resolution of the image recorded on the recording medium is reduced, or the reciprocating movement of the recording head is required.

  As a configuration for solving such a problem, a so-called staggered arrangement in which the positions of the nozzles N3m, N3m + 1, and N3m + 2 are shifted as shown in the plan view of FIG. 2. Related Art Inkjet recording apparatuses that drive and record at different timings are known (see Patent Documents 1 and 2). That is, in such an ink jet recording apparatus, one phase and two phases are provided for each of the three nozzles N3m, N3m + 1, and N3m + 2 arranged in the direction orthogonal to the conveyance direction of the recording medium P indicated by the arrow Z in the drawing. The three-phase drive is driven with three phases.

  Here, m is an integer of 0 or more, and the nozzle number starts from 0. In addition, hereinafter, a group of nozzles composed of a plurality of nozzles N3m represented by a nozzle number of 3m is referred to as a nozzle group N3m, and a group of nozzles composed of a plurality of nozzles N3m + 1 represented by a nozzle number of 3m + 1. A group of nozzles consisting of a plurality of nozzles N3m + 2 whose nozzle number is represented by 3m + 2 is called a group N3m + 1.

  The three nozzle groups N3m, N3m + 1, and N3m + 2 are arranged on parallel straight lines l1, l2, and l3, respectively. The interval between the straight lines l1, l2, and l3, that is, the stagger pitch, is usually the recording medium P. It is set to 1/3 of the above pixel pitch.

  In an ink jet recording apparatus using such a three-phase driving recording head, conventionally, ink ejection from the nozzle group of the recording head has been controlled so as to perform recording at a period as shown in FIG. In FIG. 22 and the following drawings, the recording medium P is transported in the transport direction Z and moves upward in the figure. The hatched circles represent pixels on the recording medium P from which ink has been ejected, and they move upward in the figure as the recording medium P is conveyed. Therefore, in the drawing, the upper pixel represents a pixel from which ink has been ejected at an old timing, and the lower pixel position represents a pixel position from which new ink has been ejected.

  In FIG. 22, STB1 indicates a nozzle group N3m, STB2 indicates a nozzle group N3m + 1, and STB3 indicates a strobe (STB) pulse for switching the phase of the nozzle group N3m + 2. In the case of FIG. 22, the nozzle group N3m is controlled to be driven in the first phase, the nozzle group N3m + 1 is driven in the second phase, and the nozzle group N3m + 2 is driven in the third phase.

  In FIG. 22, the nozzle groups N3m, N3m + 1, and N3m + 2 of each phase are controlled so that the phase is switched at any timing in the strobe pulse width. That is, this phase switching corresponds to the frequency, and the strobe pulse width corresponds to the period of each phase. In the conventional recording method, the nozzle groups N3m, N3m + 1, N3m + 2 driven in the first phase, the second phase, and the third phase are linearly recorded in the direction perpendicular to the transport direction Z. Therefore, the phase is controlled to be switched three times by the strobe pulse within the time of one pixel.

  By such phase switching, when ink is ejected in order of the nozzle group N3m, N3m + 1, N3m + 2 from the nozzle group N3m on the upstream side in the transport direction Z, the ink is more than the nozzle group N3m of the first phase. Ink is ejected from the second-phase nozzle group N3m + 1, but the recording pixel position of the nozzle group N3m + 1 is shifted in the transport direction Z by the stagger pitch, and the recording medium P moves by this amount. Since this takes time, as a result, the pixels adjacent to the recording pixels ejected by the nozzle group N3m in the direction orthogonal to the transport direction Z are recorded.

  Similarly, ink is ejected from the third-phase nozzle group N3m + 2 later than the second-phase nozzle group N3m + 1. However, compared with the nozzle group N3m + 1, the recording pixel position is in the transport direction by the stagger pitch. Since it is shifted to Z, the recording pixels ejected by the nozzle group N3m + 1 and the pixels adjacent in the direction orthogonal to the transport direction Z are recorded. As described above, according to the conventional ink jet recording apparatus, pixels can be recorded linearly by using the stagger pitch of the nozzle group.

  In the present invention, the upstream side and the downstream side in the relative movement direction of the recording head and the recording medium in the recording head having nozzles arranged in a staggered manner are the most in the transport direction Z in the recording head H shown in FIG. The front side is referred to as the upstream side in the relative movement direction of the recording head and the recording medium, the immediately rear side thereof as the midstream portion, and the rearmost side as the downstream side. In the case of the straight lines l1, l2, and l3 shown in FIG. 21, when the recording medium P is in the direction indicated by the arrow Z in the figure, the nozzle group N3m on the straight line l1 is connected to the recording head and the recording medium. The nozzle group on the upstream side in the relative movement direction, the nozzle group N3m + 1 on the straight line l2 is the nozzle group in the midstream portion, and the nozzle group N3m + 2 on the straight line l3 is the nozzle group on the downstream side. The distinction between the upstream side, the midstream portion, and the downstream side in the case where the recording head is a serial head system will be described later.

  As described above, the conventional staggered recording head usually has a midstream nozzle group N3m + 1 from the upstream nozzle group N3m in the relative movement direction of the recording head and the recording medium to the downstream side. The phase of the nozzle group is switched so that ink is ejected in the order of the downstream nozzle group N3m + 2, the upstream nozzle group N3m,. In the present invention, the drive phase that is sequentially switched toward the nozzle group on the downstream side in the relative movement direction is referred to as a rank phase.

  In such three-phase drive nozzle control, ink is normally ejected from each nozzle group in accordance with the timing chart shown in FIG. In the timing chart shown in FIG. 23, like the strobe pulses STB1, STB2, and STB3 shown in FIG. 22, the upper part shows the older timing, and the lower part shows the new timing, that is, the timing after the upper part. Also, in the following, the cycle in which the three-phase driving phase makes a round including the case of the rank phase and the antiphase, that is, the last strobe from the rising edge of the first strobe pulse (in this case, the strobe pulse STB1) in FIGS. A cycle until the falling edge of the pulse (in this case, the strobe pulse STB3) is called a recording period S.

  That is, while ink is ejected from each nozzle group according to the strobe pulses STB1 to STB3 in the recording cycle S (t), the amount of ink to be ejected from each nozzle group (ejection is performed in the next recording cycle S (t + 1)). The image data DATA (t + 1), which is information such as the case where the ink amount is 0), is formed by the control unit, and the image data DATA (t + 1) is generated according to the pulsed latch signal LAT (t + 1). ) Is set for each nozzle group. In the next recording cycle S (t + 1), ink is ejected from each nozzle group according to the strobe pulses STB1 to STB3 based on the image data DATA (t + 1).

On the other hand, in the ink jet recording apparatus and the ink jet recording method described in Patent Document 2, when ink is ejected from the staggered nozzle for the purpose of improving the recording speed, the recording medium is contrary to the above-described order phase. Ink discharge starts from the nozzle group N3m + 2 on the downstream side in the relative movement direction, and the upstream nozzle group N3m + 1, the upstream nozzle group N3m, and the downstream nozzle group N3m toward the upstream side. A recording method has been proposed in which the nozzle group is driven by switching the driving phase of the multiphase driving in the order of +2,. In the present invention, such a drive phase that is sequentially switched toward the upstream nozzle group in the relative movement direction is referred to as a reverse phase.
JP 2002-137388 A Japanese Patent No. 3788471

  As shown in FIG. 24, the ink jet recording method described in Patent Document 2 switches the nozzle groups in the order of STB3 → STB2 → STB1 with strobe pulses STB1, STB2, and STB3 in reverse phase. In this way, ink is ejected in the order of the nozzle groups N3m + 2, N3m + 1, N3m,..., And an image is recorded on the recording medium. In FIG. 24 and subsequent figures, in order to avoid complication of the drawing, only the recording pixel positions where the ink is ejected from the nozzle group as shown in FIG. 24 (that is, the pixel positions hatched in FIG. 22) are shown in the drawing. It will be expressed in a circle.

  In the case of FIG. 24, since ink is ejected to the recording medium P every other pixel in the transport direction Z, for example, two such recording heads H are arranged in parallel in the transport direction Z so that two nozzle rows are provided. Thus, as shown in FIG. 25, it is possible to perform recording on all the pixels on the recording medium P. The nozzle row refers to one row of nozzles formed by a plurality of nozzles having the staggered arrangement shown in FIG. Also, the numbers 1 and 2 attached to the pixel positions in FIG. 25 distinguish the pixel positions from which the nozzle groups of the two nozzle arrays N1 and N2 eject ink. For numbers.

  However, as can be seen from FIG. 25, when ink is actually ejected to the pixel positions indicated by the diagonal lines in the figure, the end in the transport direction Z of the image recorded on the recording medium is sawtoothed. It becomes a shape or becomes unclear. Therefore, normally, ink is not ejected to the shaded pixel positions. Therefore, image data for forming a so-called white image, that is, image data indicating that ink is not ejected from the nozzles at the recording timing for recording at the shaded pixel positions is recorded in each nozzle corresponding to the shaded pixel positions. Sent to the head.

  Therefore, if the three nozzles N13m + 2, N13m + 1, and N13m in the nozzle row are set as one set of nozzles, the recording method shown in FIG. There was a problem that the efficiency of use of the nozzle was not good because of the image.

  Also, as shown in FIG. 23, image data, which is information such as the amount of ink to be ejected, is set in each nozzle group for each recording cycle. As shown in FIG. 25, the nozzle group N13m + 2, the image data set in N1 3m + 1 and N1 3m corresponds to three columns in the transport direction Z on the recording medium P in each recording period (pixel columns corresponding to three horizontal columns defined by broken lines in the figure). ), And the necessary image data overlaps at each recording cycle.

  For this reason, the image data set in each nozzle group of the print head is selected from the image data for three columns on the print medium and rearranged, etc., so that the amount of image data to be processed on the RAM etc. In addition, since a part of the image data used in the previous recording cycle is also used in the next recording cycle, it is complicated to construct a procedure for reading image data and rearranging the data. It was.

  Accordingly, the present invention provides an ink jet recording apparatus capable of improving the use efficiency of the nozzles of a recording head provided with staggered nozzles and capable of reducing the amount of image data to be processed. With the goal.

In order to solve the above-mentioned problem, an ink jet recording apparatus according to claim 1
A recording head having a plurality of nozzle rows formed by a plurality of nozzles arranged in a staggered manner shifted by a predetermined interval in the relative movement direction with respect to the recording medium for each of the three-phase driving phases;
In each nozzle row, ejection is started from a nozzle group other than the nozzle group arranged on the downstream side among the three nozzle groups arranged on the upstream side, the midstream portion, and the downstream side in the relative movement direction with respect to the recording medium. And a controller that switches the nozzle group for ejecting ink in reverse phase.

According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the case where the recording is performed at the pixel position adjacent to the pixel position recorded in the previous recording period from the same nozzle for each recording period is 1 × speed. When recording, the recording head performs double speed recording for the number of nozzle rows .

The invention according to claim 3, in the ink jet recording apparatus according to claim 2, wherein the predetermined interval is one-third of the distance between the centers of the pixel position on the recording medium, and n is a positive integer In this case, the recording head includes 3n-1 nozzle rows and performs 3n-1 times speed recording .

According to a fourth aspect of the present invention, in the inkjet recording apparatus according to any one of the first to third aspects, the control unit starts ejection from a nozzle group disposed in the midstream portion. Features.

According to a fifth aspect of the present invention, in the inkjet recording apparatus according to any one of the first to third aspects, the control unit starts ejection from the nozzle group disposed on the upstream side. Features.

The invention of claim 6 is an ink jet recording apparatus according to any one of claims 1 to 5, a plurality of nozzle rows of the recording head, the singular includes one or more of the nozzle rows or It is characterized by comprising a plurality of unit heads .

  According to a seventh aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the recording head includes two nozzle rows, and the control unit includes the three nozzle groups of the nozzle rows. In one nozzle row, discharge is started from the nozzle group arranged in the midstream portion, and in the other nozzle row, discharge is started from the nozzle group arranged on the upstream side.

The invention according to claim 8 is the inkjet recording apparatus according to any one of claims 1 to 7,
The recording head is composed of a plurality of unit heads including one or a plurality of the nozzle rows, the arrangement of which can be changed in a direction orthogonal to the relative movement direction,
The control unit is also capable of switching the nozzle group for ejecting ink according to the rank phase when n is a positive integer, and the nozzle rows arranged in the relative movement direction are 3n-1 rows. When the unit heads are rearranged, the nozzle groups for ejecting ink are switched in opposite phases, and the unit heads are arranged so that the nozzle rows arranged in the relative movement direction are 3n-2 rows. When the change is made, the nozzle group for ejecting ink is switched in the order phase.

According to the first , fourth , and fifth aspects of the present invention, ink discharge is started from the nozzle group at the midstream portion or upstream of the recording head relative to the recording medium, and the nozzle group for discharging the ink is reversed. By switching with the phase, as shown in FIG. 5 or FIG. 8 to be described later, the number of pixels that become a white image is only 3 pixels per set of three nozzles, so that the use efficiency of the nozzles can be improved.

  Also, as shown in FIG. 5 or FIG. 8, since the image data read from the memory 8 is only two columns of image data on the recording medium, the image data to be transmitted to the recording head is two columns of image data on the recording medium. The image data to be processed on the RAM or the like can be reduced, and at the same time, the image data of the two pixel columns can be recorded on the recording medium. Is completed in one recording cycle, and in the next recording cycle, the pixel columns for the two columns are not recorded, and it is not necessary to read the corresponding image data from the memory 8 again. It is possible to construct a procedure for processing such as sorting and sorting very clearly and easily.

According to the second and third aspects of the invention, in addition to the effects of the respective inventions, for example, when the number of nozzle rows is two, every other pixel in the relative movement direction from one nozzle row. Ink is ejected to the position, and ink is ejected from the other nozzle row to the pixel position in the gap portion of the pixel position, so that double speed recording at double speed can be performed. In general, when the number of nozzle rows is k, ink is ejected from each nozzle row to pixel positions every k-1 pixels, and the ink is so interpolated as to mutually eject pixel positions. It is possible to perform k-times speed double speed recording by discharging. Thus, according to the invention described in claim 5, it is possible to perform double speed recording for the number of nozzle rows, and in particular, according to the invention described in claim 6, 3n-1 rows of nozzle rows. Thus, 3n-1 times speed recording can be performed.

According to the sixth aspect of the invention, in addition to the effects of the respective inventions, a plurality of nozzle rows can be easily formed by configuring the recording head with a single or a plurality of unit heads having a single or a plurality of nozzle rows. It becomes possible to do.

  According to the seventh aspect of the invention, in addition to the effects of the respective inventions, one of the two nozzle rows starts ejection from the nozzle group in the midstream portion in the relative movement direction with respect to the recording medium. In the other nozzle row, by starting ejection from the upstream nozzle group, it is possible to perform recording from the first pixel row without forming white image pixels as shown in FIG. 9 described later. It is possible to significantly improve the nozzle use efficiency.

  Further, as shown in FIG. 9, the image data read from the memory 8 may be image data for two columns on the recording medium, and the image data of the same two pixel columns is read and processed by the two nozzle columns. Therefore, the amount of image data processed on the RAM or the like is greatly reduced. Further, since the image data recording of the pixel columns for two columns on the recording medium is completed in one recording cycle and the image data of the same two pixel columns has only to be read, the image data is read. It is possible to construct the procedures of the above and the processing procedures such as rearrangement very clearly and easily.

  According to the eighth aspect of the invention, even in a recording head in which the number of nozzle rows arranged in parallel is variable, the nozzle group for ejecting ink is switched between the rank phase and the reverse phase to switch the nozzle row. It is possible to perform double speed recording for the number of columns. In particular, when the nozzle groups are switched only in the order phase as in the prior art, it is difficult to perform 3n-1 double speed printing by arranging 3n-1 nozzles (n is a positive integer), but the reverse By making it possible to switch the nozzle group by phase, it is possible to very easily and accurately perform 3n-1 times speed recording by arranging 3n-1 nozzle rows.

  Further, when 3n-1 times speed recording is performed by arranging 3n-1 nozzle rows, it is possible to perform image recording using the technology of each invention, and to effectively exhibit the effects of each invention. Is possible. When 3n-1 nozzle rows are arranged, 3n-1 times speed recording is performed in the opposite phase, and when 3n-2 nozzle rows are arranged, 3n-2 times speed recording is performed in the rank phase. Thus, various double speed recording can be performed.

  Embodiments of an ink jet recording apparatus according to the present invention will be described below with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, a flat platen 2 that supports a recording medium P on which an image is recorded from the back side is disposed in the recording unit of the ink jet recording apparatus 1 according to the first embodiment of the present invention. A conveying roller 3 for conveying the recording medium P is disposed on the upstream side and the downstream side of the conveying direction of the recording medium P of the platen 2, that is, the conveying direction indicated by the arrow Z in the drawing. Yes.

  A plurality of recording heads 4 are disposed above the platen 2 so as to extend in a direction perpendicular to the transport direction Z. For example, a plurality of recording heads 4 are arranged corresponding to ink of each color such as yellow (Y), magenta (M), cyan (C), and black (K). For example, when the ink ejected from the recording head 4 is a photo-curable ink, necessary devices such as a light irradiation device (not shown) are disposed appropriately on the downstream side in the transport direction Z of the recording head 4. Is done.

  As shown in FIG. 2, the recording head 4 is composed of unit heads 4a and 4b, each set of two for each color ink. In the present embodiment, a plurality of nozzle groups Na3m, Na3m + 1, and Na3m + 2 are formed in the unit head 4a, and one nozzle row is formed by these nozzle groups, and the unit head 4b A plurality of nozzle groups Nb3m, Nb3m + 1, and Nb3m + 2 are formed, and one nozzle row is formed by these nozzle groups. Here, m is an integer of 0 or more, and the nozzle number starts from 0.

  Since the unit heads 4a and 4b have the same configuration, the configuration of the unit head 4a will be described as a representative. The unit head 4a pushes out the ink in the ink channel and ejects it from the nozzle by the operation of a piezoelectric element actuator such as a piezo element (not shown).

  The intervals between the nozzles Na3m, Na3m + 1, Na3m + 2 in the longitudinal direction of the unit head 4a, that is, in the direction orthogonal to the transport direction Z, are the same as the pixel pitch recorded on the recording medium P. The nozzles are arranged so as to be staggered so that the intervals between the nozzle groups Na3m, Na3m + 1, and Na3m + 2 in the transport direction Z are 1/3 of the pixel pitch.

  That is, the nozzle group Na3m composed of a plurality of nozzles Na3m whose nozzle number is represented by 3 m is arranged on the straight line l1 closest to the transport direction Z in FIG. 2, and the nozzle number is represented by 3m + 1. The nozzle group Na3m + 1 composed of the plurality of nozzles Na3m + 1 is arranged on a straight line l2 parallel to the straight line l1 and shifted in the transport direction Z by 1/3 of the pixel pitch. Similarly, a nozzle group Na3m + 2 composed of a plurality of nozzles Na3m + 2 represented by a nozzle number 3m + 2 is on a straight line l3 parallel to the straight line l2 and shifted in the transport direction Z by 1/3 of the pixel pitch. Has been placed.

  In this embodiment, the nozzle group Na3m on the straight line l1 is controlled to be ejected simultaneously by the strobe pulse STB1, and the nozzle groups Na3m + 1 and Na3m + 2 on the straight lines l2 and l3 are respectively strobe pulses STB2 and STB3. The discharge is controlled at the same time. The strobe pulses STB1, STB2, and STB3 are sequentially switched for each of the three-phase driving phases, so that the nozzle group for ejecting ink can be sequentially switched, and the recording head 4 is conveyed in the conveyance direction Z. An image is recorded by ejecting ink from each nozzle group to the recording medium P.

  In the case of this embodiment, the nozzle groups Na3m and Nb3m of the unit heads 4a and 4b are nozzle groups on the upstream side in the relative movement direction of the recording head 4 and the recording medium P, that is, in the transport direction Z. The nozzle groups Na3m + 1 and Nb3m + 1 and the nozzle groups Na3m + 2 and Nb3m + 2 are nozzle groups in the middle and downstream of the relative movement direction of the recording head 4 and the recording medium P, that is, the transport direction Z, respectively.

  The control system of the ink jet recording apparatus 1 is configured by a microcomputer in which a CPU, a ROM, a RAM, an input / output interface and the like (not shown) are connected to a bus. FIG. 3 is a block diagram showing a control configuration of the ink jet recording apparatus according to the present embodiment.

  The control unit 5 performs drive control of the transport device 6 including a drive motor (not shown) that rotates the transport roller 3 described above. Moreover, the control part 5 is comprised so that those other devices and mechanisms, such as a light irradiation apparatus, may also be drive-controlled.

  In this embodiment, input image data and various setting data encoded from the host system H to the image processing unit 7 are sent. An external device (not shown) is connected to the host system H through a network. The host system H and the external device send image data for recording to the ink jet recording apparatus 1 and perform overall operation control of the ink jet recording apparatus 1. Input is to be made. The host system H and the external device can also set a drive frequency for driving the recording head 4.

  The control unit 5 sets up the head drive unit 9 by sending an instruction signal such as a drive frequency set by the host system H or an external device to the head drive unit 9. Further, the image processing unit 7 is configured to decode the input image data based on the control of the control unit 5 and send the data to the memory 8 so that the data can be processed by the inkjet recording apparatus 1.

  In the present embodiment, as shown in FIG. 4, the control unit 5 sets the strobe pulse transmitted from the head drive unit 9 to each recording head 4 so as to be switched in the order of STB2 → STB1 → STB3. After ejecting ink from the nozzle group Na3m + 1 in the middle stream, eject ink from the nozzle group Na3m on the upstream side, and then eject ink from the nozzle group Na3m + 2 on the downstream side. The nozzle groups to be switched are sequentially switched in the opposite phase, and ejection driving is performed in the order of Na3m + 1 → Na3m → Na3m + 2 →.

  The unit head 4b is driven in the same manner. As shown in FIG. 5, the ink ejected from the nozzle group of the unit head 4b is landed on the recording medium by the ink ejected from the nozzle group of the unit head 4a. A strobe pulse is transmitted from the head drive unit 9 to the unit heads 4a and 4b so as to be discharged to a pixel position adjacent to the unit head 4a.

Of the symbols a ₀ , b _1, etc. attached to the pixel positions in FIG. 5, the alphabet represents which of the unit heads 4a, 4b the ink is ejected from, and the numbers represent the ink The nozzle numbers 3m, 3m + 1 and 3m + 2 of the nozzle group to be discharged are represented by 0, 1 and 2, respectively.

  Further, as shown in the timing chart shown in FIG. 23 described above, the head driving unit 9 performs ink from each of the nozzle groups 3m + 1, 3m, and 3m + 2 according to the strobe pulses STB2 → STB1 → STB3 in the recording cycle S (t). Image data DATA (t + 1), which is information such as the amount of ink to be ejected from each nozzle group in the next recording cycle S (t + 1), is read out from the memory 8 during When the latch signal LAT (t + 1) is transmitted from the control unit 5 by performing processing such as rearrangement of the image data DATA (t + 1) for setting, the latch signal LAT (t + 1) Accordingly, image data DATA (t + 1) is set to each nozzle.

  Then, the head drive unit 9 switches the strobe pulse to be transmitted to each unit head as shown in FIG. 4 in the set order STB2-> STB1-> STB3, and any of the strobe pulses STB2, STB1, STB3 is ON. Ink is appropriately discharged from the nozzle group in the state.

  Note that the time interval from the rise to the fall of each strobe pulse STB2, STB1, STB3 for the three nozzle groups shown in FIG. 4 is 2 of the time interval from the rise to the fall of each strobe pulse shown in FIG. Although it is described as being doubled, this does not indicate that the time interval from the rise to the fall of the strobe pulse has doubled, and the time interval from the rise to the fall is shown in FIG. This is the same as in the case of FIG. 5, and shows that the conveyance speed of the recording medium P has doubled.

  That is, when the case where the recording is performed at the pixel position adjacent to the pixel position recorded at the previous recording period from the same nozzle group for each recording period as shown in FIG. Then, recording is performed at every other pixel position from the same nozzle group as shown in FIG. 4 and the like with the same recording period as that shown in FIG. That is, the ink jet recording apparatus 1 according to the present embodiment is configured to perform recording twice as high as when the recording medium P is transported at 1 × speed, that is, at 2 × speed recording. Therefore, the recording time is halved.

  Next, the operation of the ink jet recording apparatus 1 according to this embodiment will be described.

  In the recording by the ink jet recording apparatus 1 according to the present embodiment, as shown in FIG. 5, the pixel position in the gap portion of the pixel position recorded by the unit head 4a of the recording head 4 is recorded by the unit head 4b. All pixels of the recording medium P are recorded.

  In image recording, the head drive unit 9 reads out image data for determining the ejection amount from each nozzle in the next recording cycle from the memory 8, performs processing such as rearrangement of the image data, and latches from the control unit 5. When a signal is transmitted, image data is set in each nozzle accordingly.

  At this time, as shown in FIG. 5, the head drive unit 9 records the nozzle group Na3m + 1 in the middle flow direction Z of the unit head 4a, the upstream nozzle group Na3m, and the downstream nozzle group Na3m + 2. Image data of two pixel columns on the power recording medium (two horizontal pixel columns in the figure divided by broken lines) is read from the memory 8 and rearranged. In addition, the nozzle group Nb3m + 1, the upstream nozzle group Nb3m, and the downstream nozzle group Nb3m + 2 in the middle portion in the transport direction Z of the unit head 4b have two pixel columns on the recording medium to be recorded (in the drawing). Then, the image data of two horizontal columns divided by broken lines is read from the memory 8 and rearranged.

  The head drive unit 9 switches the strobe pulses to be transmitted to the unit heads 4a and 4b in the set order STB2 → STB1 → STB3, and in that order to each nozzle group Na3m + 1, Na3m, Na3m + 2. At the same time as the ink is appropriately ejected from the nozzles to which it belongs, the operation of reading out the image data of the pixel columns for two columns from the memory 8 for each of the unit heads 4a and 4b for the next recording cycle, and rearranging them is repeated. Note that the above-described signal for forming a white image is sent to the nozzles that eject ink to the pixel positions indicated by hatching in FIG. Accordingly, no ink is ejected from the nozzles at the pixel positions.

  As described above, according to the ink jet recording apparatus 1 according to the present embodiment, it is possible to perform recording at twice the speed as compared with the single speed recording as in the conventional recording method shown in FIG. Become. Further, even in the same double speed recording, as shown in FIG. 25, in the inkjet recording apparatus 1 according to the present embodiment, compared to the case where the nozzle group is driven in the reverse phase in order from the nozzle group on the downstream side in the transport direction Z, As shown in FIG. 5, the number of pixels that become a white image is three pixels in total for one set of three nozzles, so that the use efficiency of the nozzles can be improved.

  Further, in the conventional recording method shown in FIG. 25, image data for three columns is read from the memory 8 on the recording medium in order to set the nozzles of the recording head 4 at each recording period, and these are read on the RAM or the like. Although it has been necessary to perform rearrangement or the like, in the ink jet recording apparatus 1 according to the present embodiment, as shown in FIG. 5, the image data read from the memory 8 may be image data for two columns on the recording medium.

  Therefore, it is possible to select image data to be transmitted to the recording head from the image data for two columns on the recording medium and perform processing such as rearrangement, and the amount of image data to be processed on the RAM is reduced. Is done.

  Further, as described above, in the conventional recording method shown in FIG. 25, the image data for the three columns set in the nozzle partially overlap every recording period, so the image data reading procedure and data arrangement are arranged. Although the construction of processing procedures such as replacement has become complicated, in the present embodiment, the recording of the image data of the pixel columns for two columns on the recording medium is completed in one recording cycle, and the next In this recording cycle, the pixel columns for the two columns are not recorded, and it is not necessary to read the image data for that amount from the memory 8 again. Therefore, it is necessary to construct a procedure for reading the image data and a processing procedure such as rearrangement. It can be done very clearly and easily.

In the present embodiment, as shown in FIG. 2, an inkjet in which two nozzle rows are formed for each color ink by providing two unit heads 4 a and 4 b each having one nozzle row. Although the recording apparatus 1 has been described, for example, as shown in FIG. 6, the recording apparatus 4 is configured to include one recording head 4 ^* in which two nozzle arrays are formed at predetermined intervals, for each color ink. Is also possible. Even when the recording head is configured in this way, the same effect as in the present embodiment can be obtained.

[Second Embodiment]
In the ink jet recording apparatus according to the second embodiment of the present invention, the configuration of the recording unit is the same as that of the first embodiment shown in FIG.

  In the ink jet recording apparatus according to the second embodiment, the configuration of the recording head 4 is the same as that of the first embodiment shown in FIG. 2, and the unit head 4a has a nozzle group for discharging ink in reverse phase. Although the same is true for the point where switching is performed sequentially, as shown in FIG. 7, unlike the first embodiment in that ink discharge is started from the nozzle group Na3m on the upstream side in the transport direction Z of the recording medium P, the downstream side thereafter. The nozzle groups ejecting ink in the order of the nozzle group Na3m + 2 and the nozzle group Na3m + 1 at the midstream portion are sequentially switched in reverse phase. The unit head 4b is similarly configured.

  Therefore, the control unit transmits strobe pulses that are switched in the order of STB 1 → STB 3 → STB 2 from the head drive unit 9 to each recording head 4 so as to eject ink from each nozzle group in this order. Then, the head drive unit 9 reads out the image data to be ejected from each nozzle in the next recording cycle for two pixel columns from the memory 8 and performs processing such as rearrangement of the image data in order to set to each nozzle, Image data is set in each nozzle in accordance with a latch signal from the control unit.

  When the ejection control is performed in this way, the ink ejected from the nozzles of the unit heads 4a and 4b from the unit heads 4a and 4b of each recording head 4 alternately on the recording medium as shown in FIG. Recorded in line. In this case, double-speed recording is performed. It should be noted that a white image is formed at the pixel position indicated by hatching in FIG. 8, that is, no ink is ejected from the nozzle at this pixel position.

  As described above, in the ink jet recording apparatus according to the second embodiment, it is possible to perform recording at double speed similarly to the ink jet recording apparatus 1 according to the first embodiment, and at the same time, a pixel that becomes a white image. However, since a total of three pixels per nozzle made up of three nozzles is sufficient, the use efficiency of the nozzles can be improved.

  Also in the ink jet recording apparatus according to the present embodiment, as shown in FIG. 8, the image data read from the memory 8 may be two columns of image data on the recording medium, and therefore the image data to be processed on the RAM or the like. Since the amount of image data is reduced and the recording of image data of two columns of pixels on a recording medium is completed in one recording cycle, a procedure for reading out image data and a procedure for processing such as rearrangement are constructed. Can be performed very clearly and easily.

Also in this embodiment, the recording head can be configured like the recording head 4 ^* shown in FIG.

[Third Embodiment]
In the ink jet recording apparatus according to the third embodiment of the present invention, the configuration of the recording unit is the same as in the case of the first embodiment and the second embodiment described above. .

  In the ink jet recording apparatus according to the third embodiment, the configuration of the recording head 4 is the same as that in the first embodiment shown in FIG. 2, and the nozzle group for ejecting ink in the opposite phase is switched. Ink is ejected from the unit head 4a and the unit head 4b in a different order per head 4.

  Specifically, in the unit head 4a, the strobe pulse is switched in the order of STB1 → STB3 → STB2 as in the second embodiment shown in FIG. 7, and the nozzle group Na3m on the upstream side in the transport direction Z of the recording medium P Then, the ink discharge is started, and the ink is discharged in the order of the nozzle group Na3m + 2 on the downstream side and the nozzle group Na3m + 1 in the midstream portion. On the other hand, in the unit head 4b, the strobe pulse is switched in the order of STB2-> STB1-> STB3 as in the first embodiment shown in FIG. 4, and from the nozzle group Nb3m + 1 in the midstream portion in the conveyance direction Z of the recording medium P Ink ejection is started and ink is ejected in the order of the upstream nozzle group Nb3m and the downstream nozzle group Nb3m + 2.

  As described above, when ink is ejected in a different order between the unit head 4a and the unit head 4b, the unit heads 4a and 4b of each recording head 4 are respectively discharged from the nozzles of the unit heads 4a and 4b as shown in FIG. The ejected ink is recorded so as to be alternately arranged on the recording medium.

  As described above, also in the ink jet recording apparatus according to the third embodiment, it is possible to perform recording at double speed similarly to the ink jet recording apparatuses according to the first and second embodiments. According to the ink jet recording apparatus according to the third embodiment, it is possible to perform recording from the first pixel row without forming pixels of a white image as shown in FIG. It becomes possible to greatly improve.

  In the ink jet recording apparatus according to the present embodiment, as shown in FIG. 9, the image data read from the memory 8 for the unit heads 4a and 4b may be image data for two columns on the recording medium. Since it is only necessary to read and process the image data of the same two pixel columns with the heads 4a and 4b, the amount of image data to be processed on the RAM or the like is greatly reduced.

  Further, it is only necessary to read out image data of the same two pixel columns and rearrange the image data for each of the unit head 4a and the unit head 4b, and the pixels for two columns on the recording medium. Since the recording of the image data of the columns is completed in one recording cycle, it is possible to very clearly and easily construct the image data reading procedure and processing procedure such as rearrangement.

  Note that the order of ink ejection from the unit heads 4a and 4b is the reverse order of the present embodiment, that is, the unit head 4a has the nozzle group Nb3m + 1 → Nb3m → Nb3m + 2 as in the first embodiment. In order, the unit head 4b can be configured to switch in the order of the nozzle groups Na3m → Na3m + 2 → Na3m + 1 as in the second embodiment and combine them to eject ink. Even if comprised in this way, the completely same effect as this embodiment can be acquired.

Also in the present embodiment, the recording head can be configured as the recording head 4 ^* shown in FIG.

[Fourth Embodiment]
In the first to third embodiments, two unit heads each provided with one nozzle row as shown in FIG. 2 are provided for each color, or one recording head as shown in FIG. In the above description, the case where the recording head is configured to include two nozzle rows for each color by providing two nozzle rows has been described.

  When configured in this way, as shown in FIG. 22, when recording at the pixel position adjacent to the pixel position recorded at the previous recording cycle from the same nozzle at every recording cycle is defined as 1 × speed recording, In each of the above-described embodiments, it is possible to perform double speed recording corresponding to the number of nozzle rows, that is, double speed recording.

  More specifically, the strobe pulses STB1, STB2, and STB3 for the three nozzle groups shown in FIGS. 22 and 4 are set so that the time intervals from the rising edge to the falling edge are the same as each other. Under these conditions, compared with the case where the driving phase of the nozzle group is switched in the order phase shown in FIG. 22, in the first to third embodiments, the nozzle rows are two rows and the nozzles are in the opposite phase. By switching the driving phase of the group, double speed recording corresponding to the number of nozzle rows, that is, double speed recording could be achieved.

  However, such double speed recording is not limited to the case of two rows by two nozzle rows and double speed. It is possible to perform 3n-1 times speed printing by setting the number of nozzle rows to 3n-1 (n is a positive integer).

  For example, the unit includes five unit heads having one nozzle row as shown in FIG. 2, or one recording head having five nozzle rows as shown in FIG. 6, or a unit having one nozzle row. By providing a plurality of unit heads each including a head and a plurality of nozzle rows, the recording head is configured to have five nozzle rows.

  Further, for example, as shown in FIG. 10, strobe pulses are switched in the reverse phase in the order of STB 1 → STB 3 → STB 2 with respect to the three nozzle groups in one nozzle row, and the nozzles on the upstream side in the transport direction Z of the recording medium P Ink ejection is started from the group Na3m, and control is performed so that ink is ejected in the order of the nozzle group Na3m + 2 on the downstream side and the nozzle group Na3m + 1 in the midstream portion.

  Then, by controlling the ink to be ejected to adjacent pixel positions in each nozzle row, it is possible to achieve 5 × speed recording as shown in FIG. In this case, no ink is ejected from the nozzles at the pixel positions indicated by hatching in FIG. 11, and a total of nine pixels per nozzle, which is a set of three pixels, are formed.

  Although not shown, the strobe pulses are switched in the reverse order of STB2 → STB1 → STB3 in the order of STB2 → STB1 → STB3 as in the first embodiment for each nozzle group of the five nozzle arrays. Even if control is performed so that ink is ejected from the nozzle group Na3m + 1 at the midstream portion in the transport direction Z and the ink is ejected in the order of the upstream nozzle group Na3m and the downstream nozzle group Na3m + 2. In addition, a total of nine pixels per nozzle, which is a set of three pixels, is a white image.

  On the other hand, when the conventional ink jet recording method described in Patent Document 2 is applied, the driving phase is opposite, but the ink is ejected from the nozzle group on the downstream side in the transport direction Z of the recording medium P. In FIG. 12, the pixel positions where ink is ejected are as shown in FIG. 12, and a total of 12 pixels are required for each of the three nozzles.

  As described above, according to the ink jet recording apparatus according to the present embodiment, the same effects as those of the first and second embodiments can be exhibited in the 3n-1 times speed recording. Since it is possible to reduce the number of pixels that form a white image with respect to the ink jet recording method, it is possible to improve the use efficiency of the nozzles.

  In the present embodiment as well, as in the third embodiment, the number of pixels that become a white image is further reduced by changing the order of the strobe pulses for each nozzle row and changing the nozzle group that starts ink ejection. It is also possible to configure it.

[Fifth Embodiment]
In the first to fourth embodiments, the case has been described in which the recording head and the unit head sequentially switch the nozzle groups in the opposite phase driving phase to eject ink. However, as described above, the recording head and the unit head are usually driven in the order of phase in which the nozzle group for ejecting ink sequentially from the upstream nozzle group in the relative movement direction with respect to the recording medium is switched. is there.

  Therefore, in the fifth embodiment of the present invention, an ink jet recording apparatus that utilizes the fact that the drive phase of the recording head or unit head is switched between the order phase and the opposite phase will be described.

  In the present embodiment, the ink jet recording apparatus 10 is the same as the ink jet recording apparatus shown in FIG. 1, and unit heads 4c to 4f of the same type as the unit heads 4a and 4b shown in FIG. In this way, four are arranged for each color. Each of the unit heads 4c to 4f is movable along the guide rail 11 in a direction orthogonal to the transport direction Z. The unit heads 4c to 4f may be moved by a moving mechanism (not shown) or manually.

  When the unit heads 4c to 4f are arranged as shown in FIG. 13, the nozzle rows arranged in the transport direction Z of the recording medium P become one row for each color. In this case, as shown in FIG. In addition, by switching the strobe pulses in the order of STB1, STB2, and STB3 in order, the image recording at 1 × speed is performed.

  Further, when the unit heads 4c to 4f are moved along the guide rail 11 and the nozzle rows arranged in the transport direction Z are two rows for each color as shown in FIG. 14, the first to fourth embodiments are performed. As shown in the embodiment, double-speed image recording can be performed by switching the strobe pulse in the opposite phase and starting the ejection of ink from the nozzle group at the midstream portion or the upstream portion in the moving direction of the unit heads 4c to 4f. While becoming possible, the effect of the 1st-4th embodiment mentioned above is exhibited.

Further, when the unit heads 4c to 4f are moved along the guide rail 11 to form four nozzle rows for each color as shown in FIG. 15, the strobe pulses are switched by forward movement. Quad-speed image recording can be performed. In this case, if the nozzle group is omitted, the pixel positions where ink is ejected are as shown in FIG. Of the symbols c ₀ , d _{1 and the} like attached to the pixel positions in the figure, the alphabet represents which of the unit heads 4c to 4f the ink is ejected from, and the numbers represent the ink ejected. The nozzle numbers 3m, 3m + 1 and 3m + 2 of the nozzle group to be used are represented by 0, 1 and 2, respectively.

  In the present embodiment, the number of unit heads for each color is not limited to four. Further, if each of the unit heads 4c to 4f shown in FIG. 13 has, for example, two nozzle rows, each unit head 4c to 4f is double-speed in the opposite phase when arranged as shown in FIG. 14 can be recorded, and when arranged as shown in FIG. 14, quadruple-speed image recording can be performed in the order phase, and when arranged as shown in FIG. Recording can be performed.

  In this way, the number of variable nozzle rows can be arbitrarily changed between 3n-1 and 3n-2 (both are positive integers), and the number of nozzle rows is 3n-1. If the nozzle group is switched in the opposite phase, and the nozzle group is switched in the order phase when the number of nozzle rows is 3n-2, various double speed recording can be performed.

  As described above, according to the inkjet recording apparatus 10 according to the present embodiment, the nozzle group that ejects ink even in the recording head in which the number of nozzle rows arranged in parallel in the transport direction Z of the recording medium P is variable. By switching the drive phase between the rank phase and the reverse phase, it is possible to perform double speed recording for the number of nozzle rows.

  In particular, when the nozzle groups are switched only in the order phase as in the prior art, it is very difficult to arrange 3n-1 rows (n is a positive integer) and perform 3n-1 times speed printing. The recording pixels recorded on the recording medium P were not aligned in a single row, but by enabling the nozzle groups to be switched in reverse phase, the nozzle rows were arranged in 3n-1 rows and the 3n-1 times speed was increased. Recording can be performed very easily and accurately.

  In addition, when 3n-1 times speed recording is performed by arranging 3n-1 nozzle rows, it is possible to perform image recording using the techniques of the first to fourth embodiments described above. The effect of the fourth embodiment can be effectively exhibited.

  Further, in particular, when the inkjet recording apparatus 20 is a line head type as in the fifth embodiment, the unit head is moved from the state of FIG. 13 to the states of FIGS. 14 and 15 according to the width of the recording medium P. As described above, it is possible not only to perform double speed recording, but also to eliminate the unit head that does not discharge ink, and to use the unit head and the recording head efficiently. .

  In the first to fifth embodiments, the case where the ink jet recording apparatus is a line head system has been described. However, the present invention is also applicable to a case where the ink jet recording apparatus is a serial head system as shown in FIG. .

  In the serial head type inkjet recording apparatus 20, the recording medium P is intermittently conveyed on the surface of the plate-like platen 21 in the sub-scanning direction indicated by the arrow Y in the figure by the conveyance roller 22. Above the platen 21, a rod-shaped carriage rail 23 extends in the main scanning direction X parallel to the platen 21 and orthogonal to the sub-scanning direction Y. The carriage rail 23 has a substantially casing-shaped carriage. 24 is supported. The carriage 24 is reciprocated in the main scanning direction X along the carriage rail 23 by a main scanning mechanism (not shown).

  On the bottom surface of the carriage 24, a recording head 25 provided with a plurality of nozzles for ejecting ink to the recording medium P is mounted. In the recording head 25, for example, two unit heads 25a and 25b are arranged in parallel in the main scanning direction X for each color ink as in the above embodiments. The unit heads 25a and 25b are similar to the unit heads 4a and 4b of the above-described embodiments shown in FIG. 2, as shown in FIG. 18, nozzles Na3m, Na3m + 1, Na3m + 2 and nozzles Nb3m, Nb3m + 1. , Nb3m + 2 are staggered, and the nozzle rows are, for example, arranged in two rows (generally, 3n-1 rows). Here, m is an integer of 0 or more, and the nozzle number starts from 0.

  Then, the unit heads 25a and 25b eject ink from the nozzles while scanning in the main scanning direction X above the recording medium P stationary on the platen 21 in accordance with the reciprocation of the carriage 24, whereby the first to first units. The effects described in the fourth embodiment are also exhibited in the serial head type inkjet recording apparatus 20 in the same manner.

  In the serial head type inkjet recording apparatus 20, when the unit heads 25a and 25b move in the movement direction indicated by the arrows in FIG. 18, the nozzle groups Na3m and Nb3m of the unit heads 25a and 25b are recorded with the recording head 25. The nozzle group is in the relative movement direction with respect to the medium P, that is, on the upstream side in the movement direction of the recording head 25, and the nozzle groups Na3m + 1 and Nb3m + 1 and the nozzle groups Na3m + 2 and Nb3m + 2 of the unit heads 25a and 25b are respectively in the middle. And the nozzle group on the downstream side.

  When the recording head 25 moves in the direction opposite to the moving direction indicated by the arrow in FIG. 18, the nozzle groups Na3m + 2 and Nb3m + 2 of the unit heads 25a and 25b are upstream of the moving direction of the recording head 25. The nozzle groups Na3m + 1 and Nb3m + 1 are treated as the middle part in the movement direction, and the nozzle groups Na3m and Nb3m are treated as the nozzle groups on the downstream side in the movement direction, respectively, as described in the first to fourth embodiments. Be controlled. That is, in the serial head type inkjet recording apparatus 20, the upstream and downstream nozzle groups in the relative movement direction of the recording head 25 and the recording medium P are changed according to the moving direction of the recording head 25 and the unit heads 25a and 25b. .

  By the way, in the ink jet recording apparatuses according to the first to fifth embodiments, the nozzle positions of the nozzle rows before and after the recording medium P in the transport direction Z are shown in FIG. May be used in which the recording head is shifted by one pixel in the direction orthogonal to the transport direction Z.

  In this case, since the nozzles of the preceding and succeeding nozzle rows do not eject ink to the same pixel position, the present invention considers the preceding and following nozzle rows to be independent. That is, for example, when 3n-1 (n is a positive integer) of such recording heads are arranged in parallel, there are 3n-1 nozzle rows among the nozzle rows on the front side of each recording head. The present invention is applied assuming that there are 3n-1 nozzle rows among the nozzle rows.

1 is a schematic perspective view of a recording unit of an ink jet recording apparatus according to a first embodiment. It is a schematic plan view which shows the structure of the unit head which has the nozzle made into the staggered arrangement. It is a block diagram which shows the control structure of the inkjet recording device of 1st Embodiment. FIG. 3 is a diagram illustrating pixel positions at which ink is ejected from one unit head in the ink jet recording apparatus according to the first embodiment. FIG. 4 is a diagram illustrating pixel positions at which ink is ejected from two unit heads in the ink jet recording apparatus according to the first embodiment. FIG. 4 is a diagram illustrating a recording head in which two nozzle rows are formed. It is a figure explaining the pixel position where an ink is discharged from one unit head with the inkjet recording device of 2nd Embodiment. It is a figure explaining the pixel position where an ink is discharged from two unit heads with the inkjet recording device of 2nd Embodiment. It is a figure explaining the pixel position where an ink is discharged from two unit heads with the inkjet recording device of 3rd Embodiment. It is a figure explaining the pixel position where an ink is discharged from one unit head with the inkjet recording device of 4th Embodiment. It is a figure explaining the pixel position where an ink is discharged from five unit heads with the inkjet recording device of 4th Embodiment. FIG. 6 is a diagram illustrating pixel positions at which ink is ejected from five unit heads in a conventional recording method in which nozzle groups are switched in reverse phase for recording. FIG. 6 is a schematic plan view showing a plurality of unit heads that are movable in a direction orthogonal to the conveyance direction of the recording medium. FIG. 14 is a schematic plan view showing a state in which two unit heads of FIG. 13 are arranged in parallel. FIG. 14 is a schematic plan view showing a state in which four unit heads of FIG. 13 are arranged side by side. FIG. 16 is a diagram illustrating pixel positions at which ink is ejected when nozzle groups of a unit head in the state of FIG. 15 are switched in order phase and printing is performed at 4 × speed. 1 is a schematic plan view showing a general configuration of a serial head type inkjet recording apparatus. FIG. 2 is a schematic plan view illustrating a configuration of a unit head having nozzles in a staggered arrangement in a serial head type inkjet recording apparatus. It is a schematic plan view showing a recording head in which the nozzle positions of the front and rear nozzle rows are shifted by one pixel. (A) is a cross-sectional view illustrating the internal structure of the recording head, and (B) is a cross-sectional view illustrating a state where both side surfaces of the ink channel are bent inward. FIG. 3 is a plan view of a recording head for explaining nozzles having a staggered arrangement. It is a figure explaining the pixel position where an ink is discharged when switching a nozzle group by a rank phase and recording at 1 time speed. It is a figure which shows the timing chart in the nozzle control of a three-phase drive. FIG. 6 is a diagram for explaining pixel positions at which ink is ejected by the ink jet recording method described in Patent Document 2. FIG. 25 is a diagram illustrating pixel positions where ink is ejected when ink is ejected as shown in FIG. 24 by two recording heads arranged in parallel.

Explanation of symbols

1, 10, 20 Inkjet recording apparatus 4, 25 Recording head 4a-4f, 25a, 25b Unit head 5 Control unit N Nozzle Na3m-Na3m + 2, Nb3m-Nb3m + 2 Nozzle group P Recording medium X Relative moving direction (main Scanning direction)
Z Relative movement direction (transport direction)

Claims (8)

A recording head having a plurality of nozzle rows formed by a plurality of nozzles arranged in a staggered manner shifted by a predetermined interval in the relative movement direction with respect to the recording medium for each of the three-phase driving phases;
In each nozzle row, ejection is started from a nozzle group other than the nozzle group arranged on the downstream side among the three nozzle groups arranged on the upstream side, the midstream portion, and the downstream side in the relative movement direction with respect to the recording medium. And an ink jet recording apparatus comprising: a control unit that switches a nozzle group for discharging ink in reverse phase. When recording at the pixel position adjacent to the pixel position recorded at the previous recording period from the same nozzle for each recording period, the recording head performs the double speed corresponding to the number of nozzle rows. The inkjet recording apparatus according to claim 1, wherein recording is performed . The predetermined interval is one third of the center interval of pixel positions on the recording medium,
3. The ink jet recording apparatus according to claim 2 , wherein when n is a positive integer, the recording head includes 3n-1 nozzle rows and performs 3n-1 times speed recording. 4. The inkjet recording apparatus according to claim 1 , wherein the controller starts ejection from a nozzle group disposed in the midstream portion . 5. Wherein the control unit, an ink jet recording apparatus according to any one of claims 1 to 3, characterized in that to start the discharge from the nozzle group disposed on the upstream side. Wherein the plurality of nozzle rows of the recording head is in any one of claims 1 to 5, characterized in that constructed by providing one or more unit heads with one or more of the nozzle row The ink jet recording apparatus described. The recording head includes two rows of the nozzle rows,
The control unit starts discharge from the nozzle group arranged in the middle stream portion in one nozzle row among the three nozzle groups of each nozzle row, and is arranged on the upstream side in the other nozzle row. 2. An ink jet recording apparatus according to claim 1, wherein ejection is started from a nozzle group. The recording head is composed of a plurality of unit heads including one or a plurality of the nozzle rows, the arrangement of which can be changed in a direction orthogonal to the relative movement direction,
The control unit is also capable of switching the nozzle group for ejecting ink according to the rank phase when n is a positive integer, and the nozzle rows arranged in the relative movement direction are 3n-1 rows. When the unit heads are rearranged, the nozzle groups for ejecting ink are switched in opposite phases, and the unit heads are arranged so that the nozzle rows arranged in the relative movement direction are 3n-2 rows. The inkjet recording apparatus according to any one of claims 1 to 7, wherein when the nozzle group is changed, the nozzle group for ejecting ink is switched in a rank phase.

Images