JP6942181B2 - An inkjet printhead having a plurality of aligned droplet ejectors and how to use the inkjet printhead. - Google Patents

Description

The present invention belongs to the field of inkjet printing, and more specifically relates to a droplet ejector array used in a rapid, highly reliable, high resolution inkjet printhead.

Inkjet printing is usually completed by drop-on-demand inkjet or continuous inkjet printing. In drop-on-demand inkjet, droplets are formed and ejected onto a recording medium using a droplet ejector equipped with a pressure boosting (eg, thermal or piezoelectric) brake. The selective activation of the brake results in the formation and ejection of droplets, which pass through the space between the printhead and the recording medium and collide with the recording medium. The formation of a printed image is achieved by controlling the formation of each droplet, which is also the mechanism for printing the desired image.

While the droplets are ejected, the recording medium keeps the printhead stationary with respect to the movement of the printhead, even if the recording medium advances and drives through the printhead when the droplets are ejected. Well, or it may be to keep the recording medium stationary and move the printhead. Previous print structures are suitable if the droplet ejector array on the printhead can cover the area of interest for printing over the width of the recording medium. Such printheads are sometimes referred to as page width printheads. The second type of printer structure is a sliding frame type printer, where the droplet ejector array of the printhead is smaller than the area of interest for printing in the width of the recording medium, and the printhead is attached to the sliding frame. In a sliding frame printer, the recording medium advances a predetermined distance along the medium advance direction and stops. At the same time when the recording medium is stopped, the sliding frame moves in the scanning direction of the sliding frame on which the print head whose ejection hole discharges droplets is placed, and the scanning direction of the sliding frame is basically the medium. It is perpendicular to the forward direction. As soon as the sliding frame crosses the print medium, the printhead prints a strip image, after which the recording medium is advanced, the sliding frame moves in the opposite direction, and the image is printed by each strip. ..

The droplet ejector in the drop-on-demand inkjet printhead includes a pressure chamber and a discharge hole, the pressure chamber has an ink inlet for supplying ink to the pressure chamber, and the ejection hole ejects ink droplets from the chamber. .. In the prior art, two parallel droplet ejectors are displayed, and FIG. 1 (revised from Patent Document 1) exemplifies a conventional drop-on-demand thermal inkjet droplet ejector. The dividing wall 20 is formed on the substrate 10 and limits the pressure chamber 22. The discharge hole plate 30 is formed in the dividing wall 20 and includes a discharge hole 32, and each discharge hole 32 is installed in a corresponding pressure chamber 22. The ink first enters the opening in the substrate 10 or the opening surrounding the edge of the substrate 10, then passes through the ink inlet 24 and enters the pressure chamber 22 as shown by the arrows in FIG. The heater 35 as a brake is formed on the surface of the substrate 10 in each pressure chamber 22, is designed for selective activation, and ejects ink through the ejection holes 32, so that the pressure is increased by boiling a part of the ink quickly. Increase the pressure in the chamber 22.

FIG. 2 shows a prior art array structure of the droplet ejector, with the droplet ejector 60 being placed in a line on the printhead 50 along the array direction 54. For simplicity, each droplet ejector 60 displays only the pressure chamber 22 and the discharge hole 32. In the linear array 52, the distance between the ejectors 60 along the array direction is Dy. The recording medium 62 and the printhead 50 move relative to each other along the scanning direction 56, and the droplet ejector 60 can controlfully eject ink droplets onto the recording medium 62. The ink droplets fall on the recording medium 62 to form dots. The allowed image point positions 66 are limited by a pixel grid 64 that includes pixel rows 68 and pixel columns 70. Pixel to pixel spacing along the array direction of the pixel column 70 is D _y, which is the same as the spacing between the ejector 60 in the linear array 52. Distance D _x between the pixels along the scan direction 56 in the pixel row 68 is related to the ignition timing of the droplet ejectors 60. For the recording medium 62 and the printhead 50 that move relative to each other by a constant velocity V along the scanning direction 56, D _x = Vt = V / f, where t is the time interval between the continuous ignition of the droplet ejector 60. And f is the droplet ejection frequency. Due to excessive current demand for many types of printheads 50, the droplet ejector 60 cannot all ignite at the same time. In such a situation, the linear array 52 is usually not really arranged in a straight line. The droplet ejector 60 needs to be offset on demand to compensate for ignition at different times so that the ink droplets land on the recording medium 62 essentially linearly along the pixel row 68.

_{The image resolution R x} along the scanning direction 56 is 1 / D _x = f / V. In other words, the printing speed is V = f / R _x . _{R x} is directly proportional to the droplet ejector frequency f and inversely proportional to the printing speed with respect to the required image resolution along the scanning direction. The droplet ejector frequency f has a physical limit. For example, it is necessary to fill the pressure chamber 22 after discharging with ink and continuously discharge the ink.

_{The image resolution R y} along the array direction 54 is equal to 1 / D _y. Since it has a high resolution R _y with respect to the _{linear array 52, the interval D y of the} droplet ejector needs to be very small. In order to provide a good ink coating on the recording medium 62, each type of droplet ejector 60 needs to have a constant size in order to eject a sufficiently sized droplet. In thermal ink jet drop ejector, spacing D _y of a typical realization of the droplet ejector is 42.3 microns, which corresponds to the discharge hole 600 to the inch. In a thermal inkjet droplet ejector, a typical feasible droplet ejector spacing Dy is 42.3 microns, which corresponds to 100 ejection holes per inch. _{A conventional thermal inkjet printhead can provide 1200 points of resolution Ry} for each inch by providing a linear array 52 of two intersecting droplet ejectors 60.

Since a large droplet ejector (eg, a piezoelectric ejector) can achieve high resolution printing, multiple droplet ejector arrays that are offset from each other can be installed in the printhead. Revised from Reference 2. Each droplet ejector array extends horizontally along the arrangement direction 54 in FIG. Each droplet ejector in the figure includes a pressure chamber 102 and a discharge hole 100-kl, where l indicates the row number, the first row (l = 1) is at the bottom, and k indicates the position within each row to the right. Increase to. The first row droplet ejector includes ejection holes 100-11, 100-21, 100-31. The second row droplet ejector includes ejection holes 100-12, 100-22 (unlabeled) and 100-32 (unlabeled). The second row deviates a distance P from the first row along the array direction 54. It has a total of 6 rows, so the distance between the discharge holes 100-11 and 100-21 in the array direction 54 is 6P. As shown in the figure, the recording medium moves with respect to the print head, and at the same time, the droplet ejector is appropriately ignited at a suitable time to form a horizontal line along the array direction 54 at a point formed by dropping the droplet on the recording medium. be able to. The leftmost point in FIG. 3 is discharged from the discharge holes 100-11. The adjacent point on the right side (displayed at the distance P located on the right side of the leftmost point) is discharged from the discharge holes 100-12. A droplet ejector array using such a two-dimensional "cross grid" can provide high resolution printing even if each droplet ejector is larger than the point spacing P. When the recording medium moves in the scanning direction 56 with respect to the cross grid of the droplet ejector, the points forming another horizontal line can be printed.

For example, as shown in FIG. 4 of the prior art (revised from Patent Document 3), in order to provide space for the ink supply and the circuit, even a thermal inkjet type compact droplet ejector has a plurality of droplet ejectors. It is also useful to place it on a line that can be touched. The printhead module 210 (shown in plan view in FIG. 4) is one of a plurality of printhead modules 210, and they are end-to-end connected to the butt edge 214 to extend the length of the printhead. Assembled like this. The array 211 of the droplet ejector 212 exhibits an inclined shape with respect to the non-butting edge portion 209 of the printhead module 210. Ink can be supplied by a segmented ink supply channel 220 from the back of the printhead module 210, the segmented ink supply channel 220 including an ink supply groove 221 extending from the back to the top. Then, the ink flows from the ink supply groove 221 into the ink inlet 24 (FIG. 1) and enters the pressure chamber 22 (FIG. 1) of the ink ejection device 212. The segmented ink supply channel 220 is installed beside the array 211 of the ink ejection device 212. A circuit 230 is installed between the array 211 and the adjacent butt edge 214 to provide a drive transistor that ignites and inspires the ink ejection device 212 to provide an electrical pulse and a logic electronic device that controls the drive transistor. An accurate droplet ejector 212 that can be included ignites at the appropriate time. The electrical contacts 240 extend along one or two non-butting edges 209 to provide electrical signals to circuit 230. The recording medium (not shown) advances with respect to the printhead module 210 along the scanning direction 56.

As shown in FIGS. 5A and 5B (revised in Patent Document 4 (JP'735)), combining a plurality of printheads in which corresponding ejection holes are aligned with each other causes a plurality of ink droplets at each point. It is possible to form a pixel point having. The printheads 2 and 4 are attached to a common sliding frame (not shown) that moves along the scanning direction 56. The corresponding discharge holes 18 in the printheads 2 and 4 are aligned along the scanning direction 56. The size of the droplet ejector is set so that the amount of ink droplets provided for ejection is half the amount of droplets for forming a point of the required size on the recording medium. FIG. 5A displays a half size point 40 printed only by the discharge hole 18 in the print head 2. FIG. 5B shows overlapping points formed by the discharge holes 18 of the two printheads 2 and 4. Patent Document 4 describes an example of using three or more printheads aligned with the more general ejection hole 18, and the size of the droplet ejector provides an amount of ink droplets that is inversely proportional to the number of printheads. Is set to. One advantage of the combination is that the printing speed can be improved.

A plurality of printheads having corresponding discharge holes aligned with each other have been described in Patent Document 5 (JP'135). In JP'135, the two printheads of each single-row droplet ejector are arranged in a manner similar to FIG. 5A (revised from JP'735). In JP'135, the aligned droplet ejectors in the two printheads are ignited in a controllable manner, the points in the scanning lines formed are from each printhead, and the droplets in the droplet ejector in the two printheads. Compensate for volume non-uniformity.

During the useful life of the printer, the droplet ejector can fail. For example, the driver can cause electrical failure, for example, the resistance heater in the thermal inkjet droplet ejector fails. Alternatively, the ejection hole of the droplet ejector can be closed. Responsible for printing all pixels on a line along the scanning direction 56 with a single drop ejector used for one-way printing on an inkjet printhead (eg, as shown in FIGS. 2-4). The irreparable obstruction of a single droplet ejector results in one unacceptable white streak along the scan direction 56 in the image. Sliding frame printers can mask the effects of droplet ejector failure by multiple path printing. In multiple-pass printing, the recording medium advances along the print scanning direction during each pass, so the dotted line of each strip printed along the sliding frame scanning direction is printed by the plurality of droplet ejectors. However, multiple pass printing significantly reduces print production.

Although the placement of droplet ejectors in inkjet printheads has already advanced, printhead and printing system design and printing orientation are still required, and even with high-speed single-pass printing, one or more droplets. It is possible to provide high-resolution printing with high reliability and image uniformity even in a situation where the ejector fails.

U.S. Patent No. 7,163,278 U.S. Patent No. 7,300,127 U.S. Patent No. 8,118,405 Japanese Patent Application Publication No. 10-151735 Japanese Patent Application Document No. 10-157135 U.S. Patent No. 6,991,318

According to one aspect of the invention, the inkjet printhead comprises a two-dimensional ejector array composed of a plurality of columns. Each column contains multiple rows, and each row contains multiple sets. Each set contains a plurality of droplet ejectors and is basically aligned along the first direction. The plurality of sets in each row are spaced apart from each other along the first direction and offset from each other along the second direction. The rows in each column are spaced apart from each other along the first direction and offset from each other along the second direction. The columns are offset from each other along the second direction. The two-dimensional array has a width W along the first direction and a length L greater than W along the second direction. Each droplet ejector in the two-dimensional array includes a ejection hole, an ink inlet, a pressure chamber and a driver. The ink inlet communicates fluidly with the first ink source. The pressure chamber communicates fluid with the discharge holes and the ink inlet. The driver can be selectively driven to pressurize the pressure chamber and eject ink through the ejection holes.

According to another aspect of the invention, the inkjet printing system includes an ink source, a printhead, a set of transfer mechanisms, an image data source and a controller. The printhead includes a two-dimensional ejector array composed of a plurality of columns, each column containing a plurality of rows, each row containing a plurality of sets, and each set containing a plurality of droplet ejectors. The droplet ejectors in each set are basically aligned along the first direction. The plurality of sets in each row are spaced apart from each other along the first direction and offset from each other along the second direction. The rows in each column are spaced apart from each other along the first direction and offset from each other along the second direction. The columns are offset from each other along the second direction. The printhead further includes a circuit that selectively ejects ink from the droplet ejector. The transfer mechanism provides relative movement between the printhead and the recording medium along a scanning direction that is essentially parallel to the first direction. Image data sources provide image data. The controller includes an image processing unit, a transfer control unit, and an ejection control unit, ejects ink droplets to a recording medium, and prints a pattern dot matrix corresponding to the image data. The plurality of droplet ejectors in the first set are installed so as to fit each other and print the straight points of the first set along the scanning direction.

The printhead and inkjet printing system according to the present invention have advantages. Due to the redundancy of the droplet ejector in the print scanning direction, the printhead can be manufactured at a high quality rate and has a long and reliable print service life. They have other advantages as well, enabling high resolution printing for high droplet ejector spacing.

According to a further aspect of the present invention, the inkjet printing system provides a method of printing an image on a recording medium. The inkjet printing system has a printhead with a set of transfer mechanisms and a two-dimensional ejector array. The transfer mechanism provides relative movement along the scanning direction for between the recording medium and the printhead. The printhead with the two-dimensional ejector array is fluid-communicated with the first ink source. The two-dimensional ejector array is composed of a plurality of columns, each column having a plurality of rows, each row having an N ₂ set, and each set having an N ₁ droplet ejector. _{The N 1} droplet ejector in each set is basically aligned along the scanning direction, and the sets in each column are offset from each other along the cross-orbital direction perpendicular to the scanning direction. The printing method includes providing image data to the printhead and using the image data to control whether or not the ejector is ignited when it is activated. During the first cycle of the first stroke, the first droplet ejector at the first end of the first set in each row in each column is activated and ignited. During the second cycle of the first stroke, the first set of second droplet ejectors in each row within each column are activated and ignited. The second droplet ejector of the first set is closest to the first droplet ejector at the first end of the first set. During the continuous cycle period after the first stroke, until all N ₁ member of the first set in each row in each column have the opportunity to eject ink of one drop any sequentially in each row in each column Activate and ignite the first set of consecutive closest droplet ejectors. _{During the N 1} + 1 cycle period of the first stroke, the first droplet ejector at the first end of the second set in each row in each column is activated and ignited. _{During the N 1} + 2 cycle period of the first stroke, the second set of second droplet ejectors in each row in each column is activated and ignited. The second set of second droplet ejectors is closest to the first droplet ejector at the first end of the second set. During the continuous cycle period after the first stroke, until all N ₁ member of the second set in each row in each column have the opportunity to eject ink of one drop both, first order in each row in each column Activate and ignite two sets of consecutive closest droplet ejectors. During the continuous cycle period after the first stroke, the other set of droplet ejectors in each row in each column, in turn, until all droplet ejectors in the two-dimensional array have the opportunity to eject one drop of ink. To start. When the recording medium moves with respect to the printhead, it activates the droplet ejector in the two-dimensional array on a series of subsequent strokes similar to the first stroke, and thus ink droplets until the image is completely printed by the image data. Dots are printed on the recording medium by ejecting.

According to a further aspect of the present invention, the inkjet printing system provides a method of printing an image on a recording medium. The inkjet printing system has a printhead with a set of transfer mechanisms and a two-dimensional ejector array. The transfer mechanism provides relative movement along the scanning direction for between the recording medium and the printhead. The printhead with the two-dimensional ejector array is fluid-communicated with the first ink source. The two-dimensional array includes a plurality of sets of droplet ejectors that are displaced from each other, each set has a plurality of droplet ejectors, and the droplet ejectors of each set are basically arranged along the scanning direction. The printing method includes providing image data to the printhead and using the image data to control whether or not the ejector is ignited when it is activated. The recording medium advances continuously with respect to the printhead along the scanning direction. The corresponding droplet ejector of the first group can be ignited as soon as it is activated. Each droplet ejector within each set of the first group can be ignited in sequence until each member of each set has a chance to ignite. The corresponding droplet ejector of the second group can be ignited as soon as it is activated. Each droplet ejector in each set of the second group can be ignited in sequence. Similarly, any other set in the 2D array is continuously ignited until all the droplet ejectors in the 2D array have a chance to ignite during the first stroke period. The recording medium moves with respect to the printhead along the scanning direction and is a two-dimensional array in a subsequent series of strokes in a manner similar to the first stroke until the image data completely prints an image using the same ink. Activate the droplet ejector inside and ignite.

The method according to the present invention has the following advantages. Each line in the scanning direction is printed by multiple droplet ejectors, thus providing high print throughput for single-pass printing and image quality for multiple-pass printing. These methods further have the advantage of multiple print modes, achieving a non-intersecting print mode in which the scan direction resolution is greater than the number of ink droplet ejectors per inch along the scan direction, and a higher scan resolution or addressing capability. Cross-printing mode that allows you to print, multi-drop pixel mode that allows each pixel to print with multiple drops to extend the color range, and redundant droplet ejector mode that compensates for defective ink droplet ejectors. Includes a low scanning resolution mode in which the scanning resolution is lower than the number of droplet ejectors per inch along the scanning direction to reduce ink usage.

Perspective view of the droplet ejector structure in the prior art Explanatory diagram showing a printhead in the prior art, including a linear array of droplet ejectors and a recording medium having a pixel grid that allows point positions. Explanatory drawing which shows the printhead in the prior art which has a plurality of rows of droplet ejectors which are displaced from each other. Explanatory drawing which shows the printhead module in the prior art which has a tilting droplet ejector array Explanatory drawing which shows the discharge hole facing structure of two print heads in the prior art, and the pattern dot matrix printed by it. Explanatory drawing which shows the discharge hole facing structure of two print heads in the prior art, and the pattern dot matrix printed by it. Explanatory drawing which shows the inkjet printing system of one Example of this invention Top view of a printhead chip of a two-dimensional array droplet ejector including a droplet ejector set arranged along the scanning direction of an embodiment of the present invention. Explanatory drawing showing the spatial relationship of the droplet ejector in the two-dimensional array similar to FIG. Explanatory drawing which is similar to FIG. 7 and shows the details of an electronic component. Explanatory drawing which shows the drive circuit and address designation circuit of one Example of this invention Explanatory drawing schematically showing a continuous time snapshot during a first print stroke period according to an embodiment of the present invention. Explanatory drawing schematically showing a continuous time snapshot during a first print stroke period according to an embodiment of the present invention. Explanatory drawing schematically showing a continuous time snapshot during a first print stroke period according to an embodiment of the present invention. Explanatory drawing schematically showing a continuous time snapshot during a first print stroke period according to an embodiment of the present invention. Explanatory drawing schematically showing a continuous time snapshot during a first print stroke period according to an embodiment of the present invention. Explanatory drawing which illustrates continuous time snapshot of the 2nd print stroke after the 1st print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 2nd print stroke after the 1st print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 2nd print stroke after the 1st print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 2nd print stroke after the 1st print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 3rd print stroke after the 2nd print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 3rd print stroke after the 2nd print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 3rd print stroke after the 2nd print stroke by one Example of this invention. Explanatory drawing which illustrates continuous time snapshot of the 3rd print stroke after the 2nd print stroke by one Example of this invention. An explanatory diagram showing a part of a pixel grid displayed according to an embodiment of the present invention, in which solid circles are printed during the three previous print stroke periods shown in FIGS. 11A and 13D. Explanatory drawing which shows four printing strokes used for double cross printing by one Example of this invention. Explanatory drawing which shows four printing strokes used for double cross printing by one Example of this invention. Explanatory drawing which shows four printing strokes used for double cross printing by one Example of this invention. Explanatory drawing which shows four printing strokes used for double cross printing by one Example of this invention. Explanatory drawing which shows five printing strokes used for triple crossing printing by one Example of this invention. Explanatory drawing which shows five printing strokes used for triple crossing printing by one Example of this invention. Explanatory drawing which shows five printing strokes used for triple crossing printing by one Example of this invention. Explanatory drawing which shows five printing strokes used for triple crossing printing by one Example of this invention. Explanatory drawing which shows five printing strokes used for triple crossing printing by one Example of this invention. Explanatory drawing showing printing of a maximum of 2 drops on each pixel according to an embodiment of the present invention. Explanatory drawing showing printing of a maximum of 2 drops on each pixel according to an embodiment of the present invention. Explanatory drawing showing printing of a maximum of 2 drops on each pixel according to an embodiment of the present invention. Explanatory drawing showing printing of a maximum of 2 drops on each pixel according to an embodiment of the present invention. Explanatory drawing which shows printing of the reverse ignition order in the order shown in FIGS. 11A-11E by one Example of this invention. Explanatory drawing which shows printing of the reverse ignition order in the order shown in FIGS. 11A-11E by one Example of this invention. Explanatory drawing which shows printing of the reverse ignition order in the order shown in FIGS. 11A-11E by one Example of this invention. Explanatory drawing which shows printing of the reverse ignition order in the order shown in FIGS. 11A-11E by one Example of this invention. An explanatory view showing a top view of a printhead chip according to an embodiment of the present invention, showing that the printhead chip is composed of a pair of two-dimensional droplet ejector arrays separated along a scanning direction. Explanatory drawing showing droplet ejector arrangement used for color printing in the prior art Explanatory drawing showing a pair of butt print head chips according to an embodiment of the present invention. Explanatory drawing which shows a pair of printhead chips which fluid-communicate with different ink sources by one Embodiment of this invention. An explanatory view showing a pair of butt printhead chips having a pair of two-dimensional droplet ejector arrays according to an embodiment of the present invention. Explanatory drawing showing a pair of butt printhead chips in which the corresponding droplet ejectors in each column are aligned along the array direction, as shown in FIG. An explanatory view showing a pair of butt printhead chips in which adjacent droplet ejector columns displace one droplet ejector spacing along the scanning direction according to an embodiment of the present invention. Explanatory drawing showing a pair of butt printhead chips including a step in which adjacent butt edges are positioned in a complementary manner. Explanatory drawing which shows the roll-to-roll inkjet printing system which can be used in some examples of this invention. Explanatory drawing which shows the sliding frame printing system which can be used in some examples of this invention. Explanatory drawing showing two sets of droplet ejectors perfectly aligned along the scanning direction. Explanatory diagram showing a set of fully aligned droplet ejectors and a set of fully misaligned droplet ejectors along the scanning direction. Explanatory drawing showing a pair of droplet ejectors and the best matching line along the scanning direction.

Needless to say, the purpose of the drawings is to explain the concept of the present invention and may not be drawn to scale. If possible, use similar drawing codes to show similar features shared in the drawings.

The present invention includes various combinations of embodiments described in the text. References to "specific examples" and similarities are that features are present in at least one embodiment of the invention. Each citation to "one embodiment" or "specific embodiment" and similar does not necessarily mean a similar single or multiple embodiments, but is intentionally pointed out or apparent to one of ordinary skill in the art. Unless this is the case, these examples are not exclusive. The citation or similar use of a single "method" or multiple "methods" is not limiting. It should be noted that the term "or" in the present invention is used in a non-exclusive sense unless otherwise expressly explained or required in the text.

Currently, the present invention will be described with reference to FIG. FIG. 6 includes a diagram showing the inkjet printing system 1 and a perspective view of the printhead chip 215. The image data source 2 provides a data signal and is translated into a droplet ejection command by the controller 4. The controller 4 includes an image processing unit 3 and prepares an image for printing. The meaning of the term "image" in the text means to include any pattern dot matrix specified by the image data. It can include an image or a text image. With the right ink, it can further include a pattern dot matrix to print the functional device. The controller 4 further includes a transfer control unit and an ejection control unit, the former controls the transfer mechanism 6, and the latter controls the ejection of ink droplets in order to print a pattern dot matrix corresponding to image data on a recording medium 62. .. The controller 4 transmits an output signal to the electric pulse source 5, and the electric pulse source 5 transmits an electric pulse to the inkjet printhead 50. The inkjet printhead 50 includes at least one inkjet printhead chip 215. The transfer mechanism 6 provides relative movement between the inkjet printhead 50 and the recording medium 62 along the scanning direction 56. In some embodiments, the printhead 50 is stationary and the transfer mechanism 6 is installed to move the recording medium 62. Alternatively, the transfer mechanism 6 can move the printhead 50 (eg, attached to a sliding frame) so as to pass through the stationary recording medium 62. When printing a continuous image strip with a sliding frame printer, the scanning direction 56 when ejecting droplets can be reversed.

Various types of recording media used for inkjet printing include paper, plastics and textiles. Recording media used in 3D inkjet printers include flat construction platforms and thin layer powder materials. Further, in various embodiments, the recording medium 62 can be fed by rolls from the form of rolls, or paper can be fed one by one from the feeding board.

The printhead chip 215 includes a two-dimensional array 150 of droplet ejectors 212 formed on the top surface 202 of the substrate 201, which substrate 201 can be made of silicon or other suitable material. The first ink source 290 supplies ink to the ejector 212 by the ink supply channel 220, and the ink supply channel 220 extends from the rear surface 203 to the upper surface 202 of the substrate 201. Ink source 290 is generally understood in the text to include any material that an inkjet printhead can eject. The ink source 290 can include, for example, color inks such as turquoise, magenta, yellow or black. Alternatively, the ink source 290 may include a conductive material, a dielectric material, a magnetic material or a semiconductor material used for functional printing. The ink source 290 can further include biomaterials or other materials. For simplicity, the position of the droplet ejector 212 is indicated by a circular ejection hole. The pressure chamber 22, the ink inlet 24, and the driver 35 (FIG. 1) are not shown in FIG. The ink inlet 24 communicates fluidly with the first ink source 290. The pressure chamber 22 and the discharge hole 32 (FIG. 1) communicate fluid with the ink inlet 24. The driver 35 can selectively pressurize the pressure chamber 22 and eject ink through the ejection holes 32.

Further referring to FIG. 1, the present invention further provides a log collection and statistical analysis system for additional data. The system includes an additional data system front-end processor, an additional data log server, an additional data main server, an additional data system database, and an additional data log database.

The two-dimensional array 150 is arranged according to a predetermined tissue structure. The basic building block of the organizational structure is set 120. Each set 120 contains N ₁ > 1 droplet ejector 212. For example, as shown in FIG. 6, each set 120 includes four droplet ejectors 212. The droplet ejector 212 in each set 120 is basically aligned along a first direction parallel to the scanning direction 56. The next high one-layer building block is row 130. Each row contains N ₂ > 1 set 120. The sets 120 in each row 130 are spaced apart from each other along the scanning direction 56 and offset from each other along the second direction. The second direction is the array direction 54 in the text. For example, as shown in FIG. 6, each row 130 contains four sets 120. The next higher tissue structure is parallel 140. Each column 140 contains N ₃ > 1 row 130. The columns 130 in each column 140 are spaced apart from each other along the scanning direction 56 and offset from each other along the array direction 54. The plurality of columns 140 are displaced from each other along the array direction 54. The two-dimensional array 150 includes N ₄ > 1 column 140. The example in FIG. 6 has nine columns 140, each column 140 containing two rows 130. The sum of the droplet ejectors in the two-dimensional array 150 is N ₁ * N ₂ * N ₃ * N ₄ , where * is the multiplication operator. The example in FIG. 6 has a total of 4 * 4 * 2 * 9 = 288 droplet ejectors 212. The width of the two-dimensional array 150 along the scanning direction 56 is W, the length along the array direction 54 is L, and L is larger than W. The array direction 54 is normally perpendicular to the scanning direction 56. For simplicity, the size of the 2D array in the drawings included in the text is relatively small. The actual printhead chip 215 can have thousands of droplet ejectors 212, and the length L is usually larger than the width W. The fact that the direction along which the length L follows is perpendicular to the scanning direction 56 realizes that a large-area recording medium 62 can be printed in single-pass or single-strip printing. Keeping the area of the printhead chip 215 relatively small is beneficial in reducing manufacturing costs. Thus, a useful size stores that the width W of the two-dimensional array 150 is slightly smaller than L, while at the same time still storing the plurality of droplet ejectors 212 in each set 120 aligning along the scanning direction 56, the width W. Is to stretch along the scanning direction 56.

FIG. 7 is a plan view of a part of the printhead chip 215 (also referred to here as a chip) and displays a part of the two-dimensional array 150. The example in FIG. 7 displays four columns (141, 142, 143 and 144). The lines on both sides of the printhead chip 215 are serrated and can have more than four columns. Each column contains two rows 131 and 132. Column 131 includes two sets 121 and 122, and column 132 contains two sets 123 and 124. Each set includes four droplet ejectors, such as, for example, droplet ejectors 111, 112, 113 and 114. The numbering rule in FIG. 7 is that the droplet ejectors in each line have serial numbers. For example, in row 131 of column 141, the numbers of the lowest to highest member of the set 121 of the droplet ejector in the set 121 are 111, 112, 113 and 114. The droplet ejector numbers in set 122 are 115, 116, 117 and 118. The droplet ejectors in one set are basically aligned along the scanning direction 56. As shown in the example in FIG. 7, N ₁ = 4, N ₂ = 2, N ₃ = 2, N ₄ ≧ 4.

Similar to FIG. 7, FIG. 8 shows the spatial positional relationship of the droplet ejectors in the two-dimensional array 150, where X is the scanning axis, its coordinates are along the scanning direction 56, and Y is the array axis. The coordinates are along the array direction 54. As shown in the lower right corner of the two-dimensional array 150, the droplet ejectors in a set are arranged at an essentially uniform spacing along the direction 56, the center distance between the droplet ejector is X ₁ (As shown between the droplet ejectors 111 and 112 in row 131 of column 144). Between adjacent sets in a row, the most central interval along the scanning direction 56 between adjacent droplets ejector is also X _1, droplet ejectors in the set 121 of rows 131 columns 144 as shown in FIG. The center distance between 114 and the droplet ejector 115 in the set 122. Therefore, in two adjacent sets in a row, the center spacing between the corresponding droplet ejectors is equal to _{X 2} = N ₁ X _1. For example, in row 131 of column 141, the distance between the lowest droplet ejector 111 in the set 121 and the lowest droplet ejector 115 in the set 122 is X ₂ = 4X ₁ .

Adjacent sets in each row are arranged at intervals by essentially homogeneously first offset Y ₁ along the array direction 54. As shown in the example of FIG. 3, the reference line 57 is parallel to the scanning direction 56 and passes through the center of the droplet ejector in each set. For example, in row 132 of column 141, the first reference line 57a passes through the center of the set 124 droplet ejectors 115, 116, 117 and 118, and the second reference line 57b is the set 123 droplet ejectors 111, 112, It passes through the centers of 113 and 114. The distance between the first reference line 57a and the second reference line 57b is equal to the first offset _{Y 1} along the array direction 54.

In one column along the scanning direction 56, the distance between the second column the most adjacent droplets ejector adjacent to the first row equals X _5, is X ₁ or more. For example, in column 144, the droplet ejector 118 in set 122 of column 131 is closest to the droplet ejector 111 in set 123 of column 132 along the scanning direction 56. As shown in FIG. 8, the distance between the two droplet ejectors along the scanning direction 56 is X _5, which is larger than _{X 1.} Spacing between the droplets ejector most adjacent second row 132 adjacent to the first row 131 of all four columns 141, 142, 143 and 144 are _{X 5} none. Therefore, the center spacing between the corresponding droplet ejectors in the corresponding set in the adjacent row is equal to _{X 3} = N ₂ * X ₂ + X _5- X _1. If X ₅ = X ₁ , the expression is simplified to _{X 3} = N ₂ * N ₁ * X _1. For example, the distance between the lowest droplet ejector 111 in the lowest set 121 of row 131 of column 141 and the lowest droplet ejector 111 in the lowest set 123 of column 132 is X ₃ = 7X ₁ + X. It is _5.

Most adjacent sets in adjacent columns in each column are arranged at intervals by the first offset Y ₁ along the array direction 54. For example, in column 141, the second reference line 57b passes through the center of the droplet ejectors 111, 112, 113 and 114 of set 123 in column 132. The closest set in adjacent columns 131 is set 122. The third reference line 57c passes through the center of the droplet ejectors 115, 116, 117 and 118 of the set 122 of the adjacent row 131. The distance between the second reference line 57b and the third reference line 57c is equal to the first offset _{Y 1} along the array direction 54.

Minimum spacing between the sets in the second column adjacent to the first set of the column extends along the array direction 54 is equal to the first offset Y _1. For example, the set in which the columns 141 and 142 have the minimum spacing along the array direction 54 is the set 121 of rows 124 and 142 of the columns 141. The first reference line 57a passes through the center of the droplet ejector of set 124 of column 141. The fourth reference line 57d passes through the center of the droplet ejector of set 121 of column 142. The distance between the first reference line 57a and the fourth reference line 57d is equal to the first offset _{Y 1} along the array direction 54.

In other words, in a two-dimensional array 150, set to be consecutively arranged (left to right in FIG. 8) are arranged at equal intervals by the first offset Y ₁ along the array direction 54. If the recording medium 62 (FIG. 6) moves with respect to the printhead chip 215 along the scanning direction 56, then along the array direction 54 in row 68 if the droplet ejectors in different sets ignite at the right time at the right time. allowability adjacent point position 66 (FIG. 2) are arranged uniformly spaced by a first offset Y _1. The point spacing along the array direction 54 is similar to the prior art as shown in FIGS. 2 and 3. In a more detailed description of such a printing method below, the formation of points along the scanning direction 56 is different from the prior art. These printing differences along the scanning direction 56 are realized by the droplet ejector set aligned along the scanning direction 56. A printhead comprising a two-dimensional array 150 composed of droplet ejectors arranged along a plurality of scanning directions 56 of each set, the printhead being arranged on a recording medium 62 along the scanning direction 56. Straight points can be printed, and these points are printed cooperatively by a plurality of different droplet ejectors in one single pass. If a single droplet ejector in a set fails, such a printhead in a single pass print will produce white streaks along the scanning direction 56 like a conventional printhead.

As mentioned above, it is beneficial to place the droplet ejectors in multiple offset rows, as such prior art shown in FIG. 4 is convenient for providing space for ink supply and circuitry. As shown in FIGS. 8 and 9, the offset of the droplet ejector set provides similar advantages. With reference to FIG. 8, in a situation where one column has a set of _{N 2 = 2 and one column has a row of N 3} = 2, the distance Y along the array direction 54 between the corresponding sets in the adjacent columns. ₄ is equal to _{4Y 1.} Broadly speaking, the distance between the corresponding sets in adjacent columns is equal to _{N 2} * N ₃ * Y _1. Thus, as shown in FIG. 9, the drive circuit 160 can be arranged in the space between the corresponding sets in adjacent columns. The driver for each droplet ejector is electrically connected to the drive circuit 160 to activate the driver. FIG. 9 further illustrates the addressing circuit 170 as an example, and the drive circuit 160 selectively activates the driver of the droplet ejector. For example, the drive circuit 160 may include a drive transistor 161 (FIG. 10), which is individually connected to each driver. To connect to the drive transistor of drive circuit 160, addressing circuit 170 can include logic elements such as data input lines, clock lines and shift registers and latches to activate the driver at the right time in the right order. , Print the image provided by image data source 2 (FIG. 6).

FIG. 10 shows an example of the drive circuit 160 and the addressing circuit 170 and may include a printhead chip 215 in an example similar to FIG. For simplicity of FIG. 10, each set within sets 121, 122, 123 and 124 has only two droplet ejectors 212, not four droplet ejectors as shown in FIG. Has _{N 4} amino columns (141,142~N ₄₎ in FIG. 10, each column has two rows 131 and 132. The addressing circuit 170 includes a plurality of address lines 171, 172, 173 and 174. Broadly speaking, the number of address lines is equal to the number of droplet ejectors in each row (the product of the number of droplet ejectors in each set and the number of sets in each row, i.e. N ₁ * N ₂ ). Each droplet ejector in a row is connected to a different address line. This means that the drive transistors 161 connected to the driver (not shown) of each droplet ejector 212 in one row are connected to different address lines. For example, in column 131, the address line 171 is connected to the drive transistor 161 corresponding to the lower ejector 125 in the set 121, and the address line 172 is connected to the drive transistor 161 corresponding to the upper ejector 126 in the set 121. 173 is connected to the transistor 161 corresponding to the lower droplet ejector 125 in the set 122, and the address line 174 is connected to the drive transistor 161 corresponding to the upper droplet ejector 126 in the set 121. Similarly, in column 132, the address line 171 is connected to the drive transistor 161 corresponding to the lower droplet ejector 125 in the set 123, and the address line 172 is the drive transistor corresponding to the upper droplet ejector 126 in the set 123. Connected to 161 the address line 173 is connected to the drive transistor 161 corresponding to the lower ejector 125 in the set 124, and the address line 174 is connected to the drive transistor 161 corresponding to the upper droplet ejector 126 in the set 124. Each address line of the addressing circuit 170 is connected to one droplet ejector 212 at a corresponding position in each set within each line. For example, the address line 171 is connected to the drive transistor 161 corresponding to the lower droplet ejector 125 in the lower set 121 in the row 131, and the address line 171 also corresponds to the lower droplet ejector 125 in the lower set 123 in the row 132. It is connected to a drive transistor 161. Also, each address line is connected to a droplet ejector at a corresponding position in each column. For example, the address line 171 is connected to the drive transistor 161 corresponding to the lower droplet ejector 125 in the set 121 in the column 141, and is connected to the drive transistor 161 corresponding to the lower droplet ejector 125 in the set 121 in the column 142. It is, are connected to the corresponding drive transistor 161 under drop ejector 125 in the set 121 in column _{N 4.} The result of the address line installation is that, for example, when transmitting a signal pulse along the address line 171 each row in each column can simultaneously ignite and fire the corresponding lower ejector 125. In fact, whether or not the previous ejector ignites and fires is determined by the image data (FIG. 6) from the image data source 2. The maximum number of droplet ejectors 215 that can be fired simultaneously by addressing in FIG. 10 is the product of the number of rows and the number of columns in each column, i.e. N ₃ * N ₄ .

Related to the addressing circuit 170 is the sequencer 175, which determines the order in which the address lines 171, 172, 173 and 174 transmit signals. For example, the signal is continuously transmitted in order according to the first sequence 171, 172, 173 and 174 of the address line, or is continuously transmitted in order according to the second sequence 174, 173, 172 and 171 which is the opposite of the first sequence. In other words, since the driver is activated according to the first sequence or the second sequence opposite to the first sequence, the installation of the address designation circuit 170 can selectively control the site selection of the drive circuit 160.

In the example described here, the number N ₁ of the droplet ejectors in each set is even. An even number of droplet ejectors in one set may be preferred for addressing, but installations that can have an odd number of droplet ejectors in each set are also considered.

As shown in the example in FIG. 8, in the column, the distance between the most adjacent droplet ejectors in the first row and the adjacent second row along the scanning direction 56 is equal to _{X 5 and is X 1} or more. If X ₅ is _{greater than X 1} , droplet ejectors at different positions in different rows can eject the droplet to the appropriate position on the recording medium 62, achieving accurate point spacing. As shown in FIG. 9, _{it is advantageous to make X 5} larger than X ₁ in some embodiments, leaving the conductor 180 between the first row 131 and the adjacent second row 132. Thermal inkjet droplet ejectors require relatively high currents, and the above advantages are especially so for such droplet ejectors. It may be beneficial to add additional leads, such as conductor 180, to the space provided between adjacent rows to avoid excessive voltage drop along the energized conductors.

Further embodiments of the printhead and the printing system will be described below, but a printing method that considers the embodiment of the printhead installation is useful. 11A-11E exemplify snapshots of sequential continuous times during the first print stroke period. One stroke is defined in a plurality of printing cycles, in which the droplet ejector 212 in the two-dimensional array 150 (FIG. 6) is ignited and in one stroke the total droplet ejector 212 in the two-dimensional array 150 (FIG. 6). ) Can be ignited once. 11A-11C _{display snapshots of three times t 1} , t ₂ and t ₄ , during which the droplet ejectors 111-114 of sets 121 and 123 in a single column eject ink droplets and record simultaneously. The medium 62 (FIG. 6) moves with respect to the printhead chip 215 along the scanning direction 56. It should be noted that the relative movement of the recording medium 62 and the printhead along the scanning direction 56 is referred to in the text as moving relative to the printhead, or printhead chip, or droplet ejector. There is. All these explanations are equally understood in the text. The relative movement of the droplet ejection period may be to transfer the recording medium through a fixed printhead, or may transfer the printhead through a stationary recording medium. .. For the sake of simplicity, the recording medium 62 (FIG. 6) is not displayed in FIG. 11, but only the position of the point is displayed. The droplet ejector, set and column numbers are similar to those used in FIGS. 7 and 8. The allowed pixel positions 300 are displayed as white circles, and already used print points are displayed as solid circles. In FIG. 11A, in the initial time _{t 1} of the first printing cycle, the droplet ejectors 111 of the corresponding a lowermost set 123 of the droplet ejectors 111 and column 132 the lowermost set 121 of column 131 is ignited simultaneously recorded the first point 301 is formed on the first position 311 of the medium, the first position 311 to the time _{t 1} is aligned to the droplet ejector 111. Whether or not the upper droplet ejector 111 actually ejects ink droplets to form the first point 301 is controlled by the image data from the image data source 2 (FIG. 6).

Recording medium basically moves relative to the liquid droplet ejector by a constant velocity V along the scan direction 56, the second time t _2, as shown in FIG. 11B, the recording medium is a phase distance with respect to the first position 311 VΔt Yes, Δt = t ₂ −t ₁ , more generally Δt = t _n −t _n-1 , where t _n is the start time of the nth print cycle. A second position 312 of _{t 2} from the first point 301 clay first position 311 to move the distance Vderutati. As shown in FIG. 11B, after the time delay Δt ignites the first set of first droplet ejectors, the second droplet ejector 112 in the set 121 of row 131 and the set 123 of row 132 prints the second set. It is activated and ignited in the cycle. Droplets ignite the discharge in the second printing cycle forms a second point 302, the point is aligned with the droplet ejector 112 to time t _2. The second droplet ejector 112 is closest to the first lowermost droplet ejector 111 in each set. The distance between the first point 301 and the second point 302 (referred to as the scanning direction pitch p) is from the distance between the droplet ejectors 111 and 112 with respect to the printhead chip 215 in the scanning direction 56 when the recording medium is in the scanning direction 56. Equivalent to subtracting the distance traveled within the t ₁ and t _{2 hour intervals, i.e. p = X 1} −VΔt. In the embodiment, the direction 127 between the first droplet ejector 111 capable of igniting in one set and the second droplet ejector 112 capable of igniting in the set is the direction in which the recording medium travels with respect to the printhead chip (scanning direction 56). ) Is the same. In such an embodiment, the scanning direction pitch p is smaller than distance X ₁ between the droplet ejectors. It has an advantage in achieving printing with a resolution higher than the number of droplet ejectors of each inch (points of each inch) on the print head in the scanning direction 56.

It repeated printing cycles by similar methods, spacing from one print cycle to the next printing time cycle begins is _{Δt = (X 1 -p) /} V. Although the third print cycle is not shown in the drawing, the droplet ejector 113 (closest to the droplet ejector 112) _{printed the third point 303 at time t 3} = t ₁ + 2Δt, but FIG. 11C shows the fourth. The print cycle is displayed and the droplet ejector 114 (closest to the droplet ejector 113) prints the fourth point 304 at _{time t 4} = t _{1 + 3Δt.} After the third printing cycle, the recording medium has already advanced the distance VΔt, and therefore the pitch p along the scanning direction between the third point 303 and the fourth point 304 is p = X ₁ −VΔt. To the initial position 311, the recording medium is already moved the total distance of 3VΔt to the printhead, all four droplet ejectors for each of the set 121 and 123 are ignited already time t _4, in該例Each set has N ₁ = 4 droplet ejectors. More broadly, the total N ₁ drop ejector in the first set of rows is ignited in time t _N1, the recording medium is moved a total distance (N 1 _-1) * VΔt to the printhead. 11A-11C show only prints using a single row of droplet ejectors as points. Similar to this, the printing of the two-dimensional array 150 (FIG. 6) is a printing in which each of the columns 140 is activated at the same time. In other words, in the N ₁ consecutive cycles engine of the first stroke, until all N ₁ member of the first set of rows each row having the opportunity for ejecting ink of one drop any, each column start sequentially The first set of closest droplet ejectors in each row of is ignited in sequence.

By a similar method, ignition of the terminal droplet ejector 115 of the second set 122 and 124 of rows 131 and 132 in each column is triggered during _{the N 1 + 1 cycle period of the first stroke. Then, during the N 1} + 2 cycle period of the first stroke, the ignition of the droplet ejector 116 (closest to the droplet ejector 115) of the second set 122 and 124 of rows 131 and 132 in each column is activated. Furthermore, during the continuous cycle period after the first stroke, until it has an opportunity each row all N ₁ member of the second set in each column for ejecting ink of one drop any second in each row in each column Activates the closest droplet ejector of the set in succession. Figure 11D displays the points already printed in the time _{t 8,} the continuous igniting Following order of droplet ejectors 111 to 114 as shown in FIG. 11 A- 11 C, the droplet ejectors in the second set 122 and 124 115 to 118 Are fired continuously in sequence and print the dots in FIG. 11D. The continuous print cycles within the first stroke are evenly spaced by Δt over time, and the scan direction pitch p = X _{1 −VΔt (X 1} and V are essentially constants) is essentially constant. The distance between the point 301 printed by the droplet ejector 111 and the point printed by the printing paper 118 after seven printing cycles is 7p. As shown in FIG. 11D, the distance that the recording medium moves from the first position 311 to the eighth position 318 with respect to the droplet ejector is 7VΔt.

In this example, the number of sets in one column is N ₃ = 2. If the number of sets in the column is greater than 2, ignition of additional sets of droplet ejectors in each row by a similar method until all droplet ejectors in the 2D array 150 have the opportunity to eject a drop of ink. Are started in order.

In FIG. 11D, the recording medium is not yet located at the position of the second stroke where printing starts. Since the pitch p is kept constant along the scanning direction 56, the recording medium must move a total distance N _{1 * p between the start time t 1 of the first stroke and the time t S of the} start of the next stroke. _{Therefore, N 1} * p = 4p as shown in FIG. 11E. At t = _{t 8} in FIG. 11D, the recording medium relative to the first position 311 to move _{7VΔt = (N 1 * N 2} -1) * VΔt. Recording medium _{t 8} (FIG. 11D) and _{t S} extra distance that needs to be moved between (FIG. 11E) is _{N 1 * p- (N 1 *} N 2 -1) VΔt = N1 * p- ( _{N 1} * N 2 -1) is a _{* (X} 1 -p). Therefore, after all N ₁ * N ₂ droplet ejectors in each row ignite the first stroke and before the start of the second stroke, the delay time τ1 = t _S −t ₈ = (N ₁ * p− (N _{1). * N 2 -1) * (X} 1 -p)) requiring / V.

12A-12D exemplify snapshots of sequential continuous times during the second print stroke period after the first print stroke. The points printed during the second stroke period are displayed as solid triangles and are classified as the points printed during the first stroke period. FIG. 12A _{displays t 1} = t _S + Δt time, and the droplet ejector 111 prints the first point 301 of the second stroke. FIG. 12B shows the fourth print cycle of the second stroke, the droplet ejectors 111, 112, 113 and 114 are already continuously ignited in sequence during the second stroke period, and the fourth point 304 of the second stroke is the droplet ejector. Aligned to 114. FIG. 12B is similar to FIG. 11C. Between FIGS. 12A and 12B, the distance traveled by the recording medium with respect to the droplet ejector is 3VΔt. FIG. 12C shows the eighth print cycle of the second stroke, the droplet ejectors 111, 112, 113, 114, 115, 116, 117 and 118 are already continuously ignited in sequence during the second stroke period and of the second stroke. The eighth point 308 is aligned with the droplet ejector 118. FIG. 12C is similar to FIG. 11D. Between FIGS. 12A and 12C, the distance traveled by the recording medium with respect to the droplet ejector is 7VΔt.

FIG. 12D is similar to FIG. 11E. The distance is displayed on the _X 5 + 7X equal to ₁ or wide _{X 5 + (N 1 * N} 2 -1) * X1, between the droplet ejector 111 of the droplet ejectors 111 and set 123 in the set 121 .. Because the droplet ejector 111 in row 132 and the droplet ejector 111 in row 131 are simultaneously ignited to provide n integer equidistant points with a pitch p between them.
It is necessary to conform to equation _{X 5 + (N 1 * N} 2 -1) * X 1 = np. (1)

In other words, in the scanning direction, the spacing between the corresponding droplet ejectors in the adjacent rows within each column is an integral multiple of p. In FIG. 12D or FIG. 13A, counting the point spacing between the droplet ejector 111 in row 131 and the droplet ejector 111 in row 132 is such that equation 1 in the example is X ₅ + 7X ₁ = 13p. Can be simplified to.

[0079] FIGS. 13A to 13D exemplify snapshots of sequential continuous times during the third print stroke period after the second print stroke. The points printed during the third stroke period are displayed as solid squares and are divided into the points printed during the first and second stroke periods. 13A-13 are similar to the corresponding figures in FIGS. 12A-12D, and detailed description of point positions and printing times will be omitted. 13A-13D indicate that the printed points linearly extend along the scanning direction 56 along the lines 351, 352, 353 and 354. As shown in FIG. 13C, adjacent dotted lines separated by the first offset Y ₁ along the array direction 54, at a distance between the droplet ejectors in the set to which the offset Y ₁ is adjacent shifts along the array direction 54 be.

The Y-axis (parallel to the array direction 54) in the recording medium is sometimes referred to as an intersecting rail. Point printed on the particular cross rail position in the recording medium in the scanning direction 56 is obtained by printing in cooperation with the N ₁ pieces of droplet ejectors corresponding set. With reference to the examples in FIGS. 8 and 13D, the points in line 351 are co-printed by the droplet ejectors 111, 112, 113 and 114 in the set 121 of row 131 in column 141. There is no single drop ejector that prints all the points in one line. Therefore, when one droplet ejectors in a set of N ₁ pieces of droplet ejectors fails, another (N 1 _-1) number of droplets ejector print the remaining points in該線, therefore white Do not display stripes. Similarly, the points in line 352 are co-printed by the droplet ejectors 115, 116, 117 and 118 in the set 122 of line 131 in column 141. The points in line 353 are printed cooperatively by the droplet ejectors 111, 112, 113 and 114 in the set 123 of line 132 in column 141. The points in line 354 are printed cooperatively by the droplet ejectors 115, 116, 117 and 118 in set 124 of line 132 in column 141.

When the recording medium moves with respect to the printhead, the droplet ejector in the two-dimensional array 150 performs a series of subsequent ignitions by an ignition scheme similar to the first stroke, eg, the second stroke described in FIGS. 12A-12D. And the third stroke described in FIGS. 13A-13D. As a result, the image data provided by the image data source 2 (FIG. 6) is used to print the ink droplets on the recording medium until the image printing is completed.

FIG. 14 shows a portion of the pixel grid 250, and solid circles show the points to be printed during the three stroke periods before shown in FIG. 13D. The ink droplets are ejected onto the recording medium to form image points, and the allowed image point positions are limited by the pixel grid 250. The print points in FIG. 13D represent dotted lines 351, 352, 353, and 354 printed by one column (parallel column 141 as shown in FIG. 8). Pixel grid 250 further displays the points printed by columns 142, 143, 144 and a plurality of different ejector columns for the previous three stroke periods. Pixel spacing along the scan direction 56 is the pitch p in the scanning direction, the pixel spacing along the direction Y of the cross rail is first offset Y _1. Since deviate the droplets ejector set along the cross rail direction first offset Y ₁ together in each column _(as shown in FIG. 8), first in the second column adjacent to the first set in the first column Since the minimum spacing between the two sets along the array direction 54 is _{equal to the first offset Y 1} (FIG. 8), the pixel grid 250 has a uniform cross rail pitch and the pitch is equal to _{the first offset Y 1.} Because of the relative movement of the recording medium and the print head during printing period, usually the scan direction pitch p and the distance X ₁ of the droplet ejector along the scanning direction 56 different. In the example shown in FIGS. 11 to 13, p = (X _{1 −} VΔt) is smaller than _{X 1.}

13D and 14 indicate that the pixel grid 250 fills during the previous three stroke periods as the recording medium advances relative to the droplet ejector along the scanning direction 56. There is one concrete line, such as line 351 in FIG. 13D, where the pixels in the third stroke print (indicated by the solid squares) are below the pixels in the second stroke print (indicated by the solid triangles). The pixels of the second stroke print are located below the pixels of the first stroke print (indicated by solid circles). In other words, as the recording medium moves up with respect to the printhead, the pixel grid 250 fills from bottom to top in continuous strokes in order. For example, the line 351 cannot have a print point above the point 304 (FIG. 11C) printed by the topmost droplet ejector 114 in the set 121 in the first stroke, and the relative movement of the recording medium. Has already moved the corresponding portion of the array direction 54 out of the last one droplet ejector 114. More broadly, pixel positions where line 351 in FIG. 14 is above boundary line 251 cannot be printed. Therefore, at the foremost part of the image, the image processing unit 3 and the controller 4 (FIG. 6) create print data and ignition order, and the corresponding pixels above the boundary line 251 are printed. Considering another method, if the recording medium 62 is a single sheet of paper, and the droplet ejector 111 in rows 131 and 132 at time t1 in FIG. 11A is ready to ignite, the front edge of the paper is If the droplet ejector 111 in row 131 has just arrived, there is no paper below the droplet ejector 111 in row 132, so the image processing unit 3 and controller 4 have the droplet ejector 111 in row 132 at this time. Do not allow ignition. The image processing unit 3 and the controller 4 format the print data and the ignition order and drop the droplets in appropriate positions to form the desired image on the recording medium 62.

In the example shown in FIGS. 11A to 13D, the points printed sequentially in one line along the scanning direction 56 are printed by the droplet ejectors in the continuous order in one set. For example, the point 301 in FIG. 11C is printed by the droplet ejector 111, the adjacent point 302 is printed by the adjacent droplet ejector 112, the next adjacent point 303 is printed by the next droplet ejector 113, and the adjacent point 302 is printed by the next droplet ejector 113. The next adjacent point 304 is printed by the next droplet ejector 114. Such a print type is referred to here as non-cross printing, and the scanning direction pitch p is _{smaller than X 1,} but cannot be arbitrarily reduced. The time between print cycles within one stroke is Δt = (X ₁ − p) / V. Since having _N 1 * _{N 2} pieces of print cycles in one stroke, the time required to print the entire droplet ejectors in a two-dimensional array 150 _{N 1 * N 2 * Δt =} N 1 * N 2 * ( an X ₁ -p) / V, the recording medium is the distance traveled at the speed V relative to the print head of the two-dimensional array is _{N 1 * N 2 * (X} 1 -p). The distance must be N ₁ * p or less. In other words, within the time to complete each stroke, the movement distance between the recording medium and the printhead along the scanning direction 56 is the distance between the first point and the second point formed along the scanning direction 56 in the recording medium. Less than or equal to the distance between, the first point is formed by the droplet ejector in one set in one row ejecting one drop of ink, and the second point is the correspondence in adjacent sets in the same row. When the distance traveled by the recording medium formed by ejecting one drop of ink from the droplet ejector is _{larger than N 1} * p, the point of printing along the scanning direction 56 during the first stroke period. There is a gap between the cluster and the point cluster that subsequently prints along the scanning direction 56 during the second stroke period. In other words, the delay time τ ₁ described with reference to FIG. 11E needs to be 0 or more. Therefore, N ₁ * N ₂ * (X ₁ −p) ≦ N ₁ * p, and
Therefore, it is simplified to _{N 2} * (X _{1 −p) ≦ p.} (2)

As a result, in the example of FIGS. 11A to 13D, the minimum value of the scanning direction pitch of non-crossing printing is
p _min = N ₂ * X ₁ / (N ₂ + 1). (3)

In the example of non-crossing printing in FIGS. 11A to 13D, the number of sets in one row is N ₂ = 2, and the minimum scanning direction pitch p is two-thirds of the _{droplet ejector spacing X 1 along the scanning direction 56.} be. For example, a two-dimensional array with 400 droplet ejectors per inch along one scanning direction can print non-intersecting points on a pixel grid, the resolution of which points along the scanning direction is 600 per inch. There are individual points.

Since the installation using the droplet ejector array described with reference to FIG. 7 prints at a higher resolution in the scanning direction, the following cross-printing method must be used. Figures 15A-15D display a higher resolution double crossover printing method by using double strokes. Double crossing strokes in which the order is continuous are hereinafter referred to as odd strokes and even strokes. For simplicity, FIGS. 15A-15D show only the droplet ejectors and point positions corresponding to sets 121 and 122 in column 131. In contrast to the double crossing example, p ₂ is the pitch in the scanning direction. FIG. 15A is similar to FIG. 11A. In FIG. 15A, at the initial time t ₁ (O ₁ ) of the first odd stroke, the droplet ejector 111 of the set 121 can ignite the first print cycle to form the first odd point 411 on the recording medium. The hollow circle displays the allowed odd point position 401 for which printing has not yet been started. The spacing between the allowed point positions printed by the first odd stroke is 2p ₂ , i.e. twice the scanning direction pitch p _2. During the printing period of the first odd stroke, the recording medium moves at a speed V in the scanning direction 56 with respect to the droplet ejector. Similar to the discussion of FIG. 11B above, after the first set of first droplet ejectors ignite, the time delay Δt is waited for, and the second droplet ejector 112 in the set 121 in row 131 has a second print cycle ( A second point 412 (FIG. 15B) can be formed by igniting (not shown). The distance between the first odd point 411 and the second odd point 412 printed on the first odd stroke is the distance that the recording medium moves during the period of time Δt from the distance between the droplet ejector 111 and 112. Equivalent to subtracting, i.e. 2p ₂ = X ₁ −VΔt. In the third to eighth printing cycles of the first odd stroke, the droplet ejectors 113, 114, 115, 116, 117 and 118 print odd points 413, 414, 415, 416, 417 and 418, respectively.

In FIG. 15B, at the initial time t ₁ (E ₁ ) of the first even stroke, the droplet ejector 111 of the set 121 can ignite the first print cycle to form the first even point 421 on the recording medium. For point of intersection printing in the scanning direction by a pitch p _2, the recording medium a distance 3p 2 _(FIG. 15B between the first print cycle (FIG. 15A) and the first printing cycle of the first even stroke of the first odd-stroke ) Is allowed to move. In other words, from the start of the first odd stroke (when the droplet ejector 111 prints the first odd point 411) to the start of the first even stroke (when the droplet ejector 111 prints the first even point 421). The time is 3p ₂ / V, during which the recording medium travels a _{distance of 3p 2} with respect to the droplet ejector in scanning direction 56. More broadly, to double crossing, when N ₁ has N ₁ pieces of droplet ejectors it is even in each set, between the start of the first odd-number stroke to the start of the first even-stroke time is equal to _{(N 1 -1) * p2 /} V of. The first even point 421 is indicated by the solid X, and the allowed point positions where printing is not activated in the first even stroke are indicated by the hollow X.

In FIG. 15C, at the initial time t ₁ (O ₂ ) of the second odd stroke, the droplet ejector 111 of the set 121 can ignite the first print cycle to form the first odd point 431 on the recording medium. To provide a constant scan direction pitch p _2, between the first print cycle (FIG. 15A) and the first printing cycle of the second odd stroke of the first odd-stroke (FIG. 15C), recording medium ink droplet ejectors for it must travel a total distance 8p _2. Similarly, between the first print cycle of the first even stroke (FIG. 15B) and the first print cycle of the second odd stroke (FIG. 15C), the recording medium must move _{5p 2 with respect to the droplet ejector.} It doesn't become. More broadly, to double crossing, when N ₁ has N ₁ pieces of droplet ejectors it is even in each set, between the start of the first even stroke to the start of the second odd-stroke Time is equal to _{(N 1} + 1) * p _{2 / V.} The first odd point 431 is represented by a solid triangle, and the allowed point positions where printing is not activated in the second odd stroke are represented by a hollow triangle.

In FIG. 15D, at the initial time t ₁ (E ₂ ) of the second even stroke, the droplet ejector 111 of the set 121 can ignite the first print cycle to form the first even point 441 on the recording medium. Since the point of printing is crossed by the scanning direction pitch p _2, between the first print cycle (FIG. 15C) and the first printing cycle of the second even-stroke of the second odd stroke (FIG. 15D), permissions record medium The movement distance to be made is 3p ₂ . The first even point 441 is represented by a solid star, and the allowed point positions where printing is not activated in the second even stroke are represented by a hollow star.

The portion adjacent to the upper right portion of FIG. 15D displays a sequence of dots to be continuously printed within the line 352. Above point 433, point 433 is printed on the second odd stroke by the droplet ejector 113, point 421 is printed on the first even stroke by the droplet ejector 111, and point 434 is printed on the second odd stroke by the droplet ejector 114. The point 422 is printed on the first even stroke by the droplet ejector 112, the point 411 is printed on the first odd stroke by the droplet ejector 111, and the point 423 is printed on the first even stroke by the droplet ejector 113. Point 412 is printed on the first odd stroke by the droplet ejector 112, point 424 is printed on the first even stroke by the droplet ejector 114, and point 413 is printed on the first odd stroke by the droplet ejector 113. .. In other words, in the non-cross printing, the continuous points arranged in one line along the scanning direction 56 are printed by the continuous droplet ejectors in one set, and in a different cross printing, one line is arranged along the scanning direction 56. The contiguous points arranged in are not printed by the contiguous droplet ejectors in one set. In the special case of some of the lines 352, the continuous points are printed by the droplet ejector in the order of 113, 111, 114, 112, 111, 113, 112, 114, 113.

In the example described with reference to FIGS. 15A to 15D, the time interval from the start of the first odd stroke to the start of the first even stroke is equal to _{3p 2 / V in order to accurately position the points and perform double crossing.} appear more generally _{(N 1 -1) * p 2} / V, the time interval from the first even stroke to the start of the second odd-stroke equal to _5p 2 / V, more generally _(N 1 +1 ) * P ₂ / V is displayed. Also, the time interval between the start of the first odd stroke and the start of the first even stroke _{can be equal to 5p 2} / V, or more generally to (N ₁ + 1) * p ₂ / V. appears, the start of the first even stroke and the time interval between the start of the second odd stroke can be equal to 3p 2 _{/ V,} or more generally _{(N 1 -1) * p 2} / V Is displayed in. From another point of view, it is optional to designate the first odd stroke as the first stroke and the subsequent first even stroke as the subsequent stroke. Similarly, the first even stroke can be designated as the first stroke and the subsequent second odd stroke can be designated as the subsequent stroke.

In double cross-printing, the scanning direction pitch p ₂ is smaller than the scanning direction pitch that can be realized by non-crossing printing, but cannot be arbitrarily reduced. In one stroke of double cross printing, the time between the print cycle is _{Δt = (X 1 -2p 2)} / V. Considering the example shown in FIGS. 15A-15D, each set has N ₁ = 4 droplet ejectors and each row has N ₂ = 2 sets. In one stroke, the time in which all eight droplet ejectors 111 to 118 be ignited all require is _{8 (X 1 -2p 2) /} V. Recording medium during this period the distance traveled at the speed V with respect to the droplet ejector along the scan direction 56 is 8 (X 1 _{-2p 2). The distance must be 3p 2} or less because there are no gaps between the point clusters.
_Thus, an _{8 (X 1 -2p 2) ≦} 3p 2,
It can be displayed in 8X ₁ ≤ 19p _2. (4)

As a result, in the example of FIGS. 15A to 15D, the minimum value of the double cross printing in the scanning direction pitch is
a _{p 2min = 8X 1/19,} (5)
The minimum value is less than half _{of X 1.}

With reference to the droplet ejector array installation described in FIG. 7, in order to print at a higher resolution in the scanning direction, the following higher cross printing method must be used. 16A-16E show how to perform triple cross-printing with higher resolution over triple stroke counts. The droplet ejector and point numbering rules are similar to FIGS. 15A-15D. Fewer single codes are used in FIGS. 16A-16E to avoid increasing unnecessary confusion in drawings that are more compact than these. 16A-16E show each first print cycle within the five continuous strokes A1, A2, A3, B1 and B2. In contrast to the triple crossing example, p3 is the scanning direction pitch. As shown in FIG. 16A, at the initial time t ₁ (A ₁ ) of the first stroke, the terminal droplet ejector of the first set ignites the first printing cycle and the first point (by the solid circle) on the recording medium. Can be formed). The hollow circle in FIG. 16A _{indicates the point position allowed for stroke A 1} , but printing has not yet been started. Spacing between the positions that it is allowed to be printed in the stroke A ₁ period is 3p _3, that is, three times the scanning direction pitch p _3. During a first print period of the stroke A _1, the recording medium is moved at a velocity V in the scanning direction 56 with respect to the liquid droplet ejector. Similar to the discussion of FIG. 15A above, after the first set of first droplet ejectors ignites, a time delay Δt is awaited, followed by a continuous printing cycle (not shown) of consecutive droplet ejectors in the first set. It ignites and forms a continuous point indicated by a solid circle in FIG. 16B. The distance between successive points to be printed on the stroke A ₁ is equal to subtracting the distance the recording medium is moved relative to the droplet ejector during the time Δt from the interval between adjacent droplets ejector, i.e. 3p ₃ = X ₁ −VΔt.

_{At the initial time t 1} (A ₂ ) of the second stroke in FIG. 16B, the rearmost droplet ejector of the first set ignites the first print cycle and is displayed on the recording medium by the first point (solid X). ) Can be formed. Since the point of printing is crossed by the scanning direction pitch _{p 3,} between the first print cycle (FIG. 16A) and the second first print cycle stroke _{A 2} of the first stroke _{A 1} (FIG. 16B), the recording medium It will allow you to move the distance 4p ₃ with respect to the droplet ejector. In other words, _{within the time 4p 3} / V between the start of _{the first stroke A 1 and} the start of the second stroke A ₂ , the recording medium moves _{4p 3} with respect to the droplet ejector in the scanning direction 56. More generally, to triple intersection, when N ₁ has N ₁ pieces of droplet ejectors is not a multiple of 3 in each set, from the start of the first stroke to the start of the second stroke The time between is equal to _{N 1} * p _{3 / V.} Hollow X in FIG. 16B _{indicates the print point position allowed for stroke A 2} , but printing has not yet been started.

_{At the initial time t 1} (A ₃ ) of the third stroke in FIG. 16C, the terminal droplet ejector of the first set ignites the first printing cycle and the first point (indicated by a solid square) on the recording medium. Can be formed). Subsequent printing in the third stroke _{A 3} is similar to the description of FIG 16A and 16B.

_{At the initial time t 1} (B ₁ ) of the fourth stroke in FIG. 16D, the rearmost droplet ejector of the first set ignites the first print cycle and is displayed on the recording medium by the first point (indicated by a solid triangle). ) Can be formed. Subsequent Printing fourth in stroke _{B 1} represents similar to the description of FIG 16A - 16C.

_{At the initial time t 1} (B ₂ ) of the fifth stroke in FIG. 16E, the rearmost droplet ejector of the first set ignites the first print cycle and is displayed on the recording medium as the first point (indicated by a solid star). Can be formed. Subsequent Printing fifth in stroke _{B 2} is similar to the description of FIG 16 A- 16 D.

Scanning direction pitch p ₃ of the triple intersection printing is smaller than the pitch that can be double cross printing is realized, but can not be arbitrarily small. In triple intersection printing, the time between the printing cycles in one stroke is _{Δt = (X 1 -3p 3)} / V. Considering the examples in FIGS. 16A-16E, each set has N ₁ = 4 droplet ejectors and each row has N ₂ = 2 sets. Time all eight ejectors be ignited all require in one stroke is _{8 (X 1 -3p 3) /} V. Recording medium during this period the distance traveled at the speed V with respect to the droplet ejector along the scan direction 56 is ₈ (X 1 -3p _3). For droplet ejectors each set there is no gap between the cluster points to be printed, the distance should be 4p ₃ or less. Therefore,
8 (X ₁ -3p ₃ ) ≤ 4p _3, which is simplified to _{8X 1} ≤ 28p _3. (6)

As a result, in the example of FIGS. 16A to 16E, the minimum value of the scanning direction pitch of triple cross printing is
a _{p 3min = 2X 1/7,} (7)
The minimum value is less than one-third _{of X 1.}

With reference to the droplet ejector array installation described in FIG. 7, a higher cross-printing method must be used to print at a higher resolution in the scanning direction. Multiple crossing printing is referred to as M crossing printing in the text, M = 2 is referred to as double crossing, and M = 3 is referred to as triple crossing. For a wide range of M-fold intersections (as shown in M = 2 and M = 3 above), in (M-1) consecutive subsequent stroke sequences after the first stroke, each stroke is scheduled for the first stroke. In each subsequent stroke of the (M-1) continuous subsequent stroke series, the ink droplets ejected by at least one ejector of each set of ink droplet ejectors form a subsequent stroke point on the recording medium, and the subsequent stroke points are scanned. The first stroke is printed between the allowed point positions on the recording medium by the crossing method in the direction.

In the example of the double intersection with reference to the description of FIGS. 15A to 15D above, the scanning direction pitch p ₂ = (X ₁ −VΔt) / 2. In the example of the triple crossing with reference to the description of FIGS. 16A to 16E above, the scanning direction pitch p ₃ = (X ₁ −VΔt) / 3. When the directions from the first set of first ignition droplet ejectors to the first set of second ignition droplet ejectors are the same in the scanning direction, the scanning direction pitch p _M = in the embodiment. (X ₁ −VΔt) / M. Simply put, _{the scanning direction pitch of p = (X 1} −VΔt) / M, M double intersection is roughly displayed in p.

In the example of double-cross printing shown in FIGS. 15A to 15D, the time between the start of the first odd-numbered stroke and the start of the first even-numbered stroke is 3 p / V because the printing point accurately falls to the double-crossed position. equally, or generally appear in the _{(N 1 -1) * p /} V than, N ₁ is an even number, the time between the start of the start and the second odd stroke of the first even-stroke 5p / Equal to V, or more generally _{displayed at (N 1} + 1) * p / V. Spread on M heavy intersection, the least common multiple of N ₁ and M is less than N _{1 *} M, the time between the start of the first stroke and the beginning of the next subsequent stroke (N 1 _-1) * p / Equal to V, the time between the start of the third subsequent stroke and the start of the next stroke _{is equal to (N 1} + 1) * p / V. When M is greater than 2, the time between the start of each of the other strokes and the start of the next stroke, in addition to the first and M strokes, _{is equal to N 1} * p / V. Further, as observed in the double crossing example above, since the stroke sequences overlap, it is optional to define which stroke is the first stroke, i.e. the time between strokes (N _1). -1) * p / V is optional to occur before or after _{the time between strokes (N 1 + 1) * p / V.}

In the triple crossing printing example described in FIGS. 16A-16E, the time between the start of each stroke and the start of the next stroke _{is equal to 4p 3} / V or is broadly _{displayed at N 1} * p / V. , N ₁ = 4, M = 3. As is generally known, for examples in which the least common multiple of _{N 1 and M is smaller than N 1} * M, the start of each stroke (including the first stroke) in M strokes and the start of the next stroke. The time between and is _{equal to N 1} * p / V.

In the above crossing example, it has already been explained that it has an advantage of having a high resolution in the scanning direction, that is, it is an increase in the number of inches in each inch along the scanning direction 56. In some embodiments, for example, a piezoelectric inkjet can eject a drop volume with a fairly wide range of known droplet ejectors. In such an embodiment, the electric pulse provided by the electric pulse source 5 (FIG. 6) can control the volume of the droplets and print smaller points than when using cross-printing as compared to non-cross-printing. can do. By such a method, the entire ink coverage can be basically kept constant. In another embodiment, for example, thermal inkjet allows a known droplet ejector to eject a droplet volume having a fairly narrow range. In some situations, the crossing method improves the ability to address along the scanning direction 56 and does not significantly improve the number of points printed in each inch. In other words, in the pixel grid, none of the allowed pixel positions are used to print the image. Conversely, the crossing method is used to fine-tune the position of the printing points. For example, if the pitch p in the scanning direction _{is essentially equal to the pitch Y 1} (FIG. 6) of the cross rail, diagonal lines that are not parallel to the array direction 54 or the scanning direction 56 can be displayed in a serrated pattern. The cross-printing scheme allows you to control the printing of specific intersections rather than adjacent intersections, which allows you to fine-tune the position of points along the scanning direction 56, thus smoothing lines or other features in the printed image. To process.

In some embodiments, printing multiple drops of ink at the same pixel position is advantageous in improving ink coverage and expanding the color gamut. Installation using the droplet ejector array described with reference to FIG. 7 doubles the number of strokes and sets the strokes appropriately, so that FIGS. 17A to 17D print two droplets on each pixel. indicate. In the same situation as FIGS. 15A-16E, for simplicity, FIGS. 17A-17D show only the droplet ejectors and point positions corresponding to sets 121 and 122 of column 131. As shown in FIG. 17A, at the initial time t ₁ (A ₁ ) of the first stroke, the terminal droplet ejector 111 of the first set 121 ignites the first printing cycle and the first point 451 (middle) on the recording medium. (Represented by a real circle) can be formed. The hollow circle in FIG. 17A _{indicates the point position allowed for stroke A 1} , but printing has not yet been started. The distance between the location points allowed in the first stroke A ₁ is a scanning direction pitch p. During a first print period of the stroke A _1, the recording medium is moved at a velocity V in the scanning direction 56 with respect to the liquid droplet ejector. Similar to the discussion of FIG. 15A, after the first set of first droplet ejectors ignites, a time delay Δt is awaited, followed by a continuous printing cycle (not shown) of successive droplet ejectors in the order of the first set. It can be ignited to form a continuous point indicated by a solid circle in FIG. 17B. The distance between successive points to be printed on the stroke A ₁ is equal to subtracting the distance the recording medium is moved relative to the droplet ejector during the time Δt from the interval between adjacent droplets ejector, i.e. p = X ₁ −VΔt.

_{At the initial time t 1} (A ₂ ) of the second stroke in FIG. 17B, the terminal droplet ejector 111 of the first set 121 ignites the first printing cycle and causes the recording medium to have a first point 461 (by a solid star). Can be formed). Since the ink droplets for printing during successive stroke period falls in the same position, between the first printing cycle of the first stroke A ₁ (FIG. 17A) and the second first print cycle stroke A ₂ (FIG. 17B), The recording medium allows the droplet ejector to travel a distance of 2p. In other words, in the time 2p / V between the start of the start of the first stroke A ₁ and the second stroke A _2, the recording medium is moved to 2p to droplet ejectors in the scanning direction 56. The hollow star in FIG. 17B _{indicates the point positions allowed for stroke A 2} , but printing has not yet been started.

As shown in FIG. 17C, at the initial time t ₁ (B ₁ ) of the third stroke, the terminal droplet ejector 111 of the first set 121 ignites the first printing cycle and causes the recording medium to have the first point 471 (middle). (Represented by a real triangle) can be formed. Since the ink droplets for printing during successive stroke period falls in the same position, between the first printing cycle of the second stroke A ₂ (FIG. 17B) and the third first printing cycle stroke B ₁ (FIG. 17C), The recording medium allows the ink droplet ejector to travel a distance of 2p. In other words, in the time 2p / V between the start of the start of the first stroke A ₁ and the second stroke A _2, the recording medium is moved to 2p to droplet ejectors in the scanning direction 56. Hollow triangles in FIG. 17C displays the position that it is allowed to stroke B _1, but still printing is not started. FIG. 17C further displays the print points that have already fallen at the same position on the recording medium. For example, the third point 463 (indicated by a solid star) printed by the droplet ejector 113 during the second stroke period is already the first point 451 (medium) printed by the droplet ejector 111 during the first stroke period. Fallen on (indicated by a real circle). Similarly, the fourth point 464 (indicated by a solid star) printed by the droplet ejector 114 during the second stroke period is already the second point printed by the droplet ejector 112 during the first stroke period. It fell on 452 (indicated by the solid circle).

_{At the initial time t 1} (B ₂ ) of the fourth stroke in FIG. 17D, the terminal droplet ejector 111 of the first set 121 ignites the first printing cycle and displays the first point 481 (indicated by the solid X) on the recording medium. Can be formed). Since the ink droplets for printing during successive stroke period falls in the same position, between the first printing cycle of the second stroke B ₁ (FIG. 17C) and the first printing cycle of the four-stroke B ₂ (FIG. 17D), The distance that allows the recording medium to move with respect to the ink droplet ejector is 2p. The hollow X in FIG. 17D _{indicates the point position allowed for stroke B 2} , but printing has not yet been started. FIG. 17D further indicates that the other points printed on the continuous stroke are in the same position on the recording medium. For example, the third point 473 (indicated by a solid triangle) printed by the droplet ejector 113 of the first set 121 on the third stroke is the first printed by the droplet ejector 111 of the first set 121 on the second stroke. It falls on point 461 (indicated by a solid star). Further, the seventh point 477 (indicated by a solid triangle) printed by the droplet ejector 117 of the second set 122 on the third stroke is the fifth point 465 printed on the second stroke by the ejector 115 of the second set 122. Fall on (indicated by a solid star). In this example, the continuous stroke after the fourth stroke can print up to two drops of ink at each allowed pixel position in the pixel grid.

More generally spread, ink droplets of the M can be printed at the same position in the M successive strokes, M is the number N ₁ following ink drop ejectors of each set. In the (M-1) continuous trailing stroke series after the first stroke, each stroke is scheduled for the first stroke, and in each trailing stroke of the (M-1) continuous trailing stroke series, each set The ink droplet ejected by at least one ejector of the ink droplet ejector forms a subsequent stroke point on the recording medium, and the subsequent stroke point is printed at a point position where the first stroke is permitted on the recording medium.

In the example shown in FIG. 17C, the first and second strokes print two drops of ink in cooperation with the allowed image point positions on the recording medium. As described above, the first pair of points 451 and 463 are co-printed at one permitted image point position by the first and second strokes. The second pair of points 452 and 464 are co-printed by the first and second strokes at other permitted image point positions. Spreading from here, the first stroke and the trailing strokes in at least one (M-1) trailing stroke sequence enable co-printing with more than one drop of ink at the allowed image point positions on the recording medium.

Another use of the ability to print dots in the same position with different strokes like this is to provide redundant printing, and in single-pass printing, if one ink drop ejector fails, it is responsible for the other. Printed by the ink drop ejector. In a sliding frame printer (as described in the background art above), the recording medium may advance along the array direction and then multiple pass printing may allow different droplet ejectors to print at specific positions on the recording medium. Can be done. However, multiple-pass printing is significantly slower than single-pass printing. As shown in FIG. 7, arranging by using droplet ejectors aligned along a plurality of scanning directions 56 can provide redundant printing for single-pass printing. As shown in FIG. 8, points in the line along the scanning direction are printed in cooperation with a plurality of droplet ejectors in one set. Therefore, if a single droplet ejector in one set fails, the scanning direction 56 No white streaks occur along. However, a failing droplet ejector results in the appearance of isolated white dots in the image. Printing using a redundant ink droplet ejector can reduce or eliminate the isolated white spots that produce a failing droplet ejector.

The difference from the printing method of each pixel multiple drops shown in FIGS. 17A to 17D is that the printing method of the droplet ejector having redundancy is 1 for one predetermined point position in the printing method of the droplet ejector having redundancy. Printed by one stroke. In other words, controlling the first stroke and at least one subsequent stroke in the (M-1) subsequent stroke sequence to co-print up to one drop of ink at the allowed image point positions on the recording medium. Can be done. Such control can be implemented by alternating which stroke is responsible for printing one point within the dotted line along the scanning direction. Such an approach reduces the number of isolated white spots produced by the failing droplet ejector. Alternatively, the method can be used as a response measure against certified print defects. Droplet ejectors that are found to be out of order can be disabled and the print data will be distributed to working droplet ejectors that can print the corresponding points. With such a method, even if one or a plurality of droplet ejectors fail, white dots can be removed and a high-quality image can be printed with high reliability.

In the various printing method examples, the recording medium is the direction 127 (FIG. 11B) from the ignitable first droplet ejector 111 in the first set 121 to the ignitable second droplet ejector 112 in the first set 121. It is the same as the moving direction (scanning direction 56) with respect to the droplet ejector. In such an embodiment, the scanning direction pitch p is smaller than distance X ₁ along the scanning direction 56 between the droplet ejectors. In another printing method embodiment, the direction from the ignitable first droplet ejector in the first set to the ignitable second droplet ejector in the first set is the direction in which the recording medium moves with respect to the droplet ejector (scanning direction 56). ) Is the opposite. In such an embodiment, the scanning direction pitch p is greater than distance X ₁ along the scanning direction 56 between the droplet ejectors.

18A-18D are similar to FIGS. 11A, 11C-11E, respectively, and display the same installation of droplet ejectors (111-118), sets (121-124) and rows (131-132). As shown in FIGS. 11A-11E, the recording medium moves with respect to the droplet ejector along the scanning direction 56. The difference is that in the print strokes shown in FIGS. 18A-18D, the order in which the droplet ejectors 111 to 118 are ignited is reversed. In FIGS. 18A-18D, the ignition order of the droplet ejectors is 118, 117, 116, 115, 114, 113, 112 and 111 instead of 111, 112, 113, 114, 115, 116, 117 and 118. The direction 128 from the ignitable first droplet ejector 118 in one set to the ignitable second droplet ejector 117 in the same set is opposite to the scanning direction 56 of the droplet ejector.

At t = t ₁ , FIG. 18A displays points 501 printed by the droplet ejector 118 in columns 131 and 132 during the first print cycle period within one print stroke. At t = t ₄ , FIG. 18B shows the point of printing after the droplet ejectors 118, 117, 116 and 115 in columns 131 and 132 ignite at the end of the fourth print cycle period. In each printing cycle, the recording medium travels a distance VΔt with respect to the droplet ejector along the scanning direction 56. The distance between the point 501 printed by the droplet ejector 118 in the first printing cycle and the point 502 printed by the droplet ejector 117 in the second printing cycle is the scanning direction pitch p = X ₁ + VΔt. In other words, Δt = (p-X ₁ ) / V. At t = t ₈ , FIG. 18C indicates the point at which all eight droplet ejectors 118-111 in each set 131 and 132 print after ignition at the end of the eighth print cycle. At t = t _S , FIG. 18D shows the print point facing the position of the droplet ejector when the next stroke is ready to begin. Similar to discuss for FIG. 11D and 11E, in order to hold the scanning direction pitch p along the scanning direction 56 constant, the recording medium is between time t _S start time t ₁ and the next stroke of the first stroke starts The total distance N ₁ * p must be traveled to, and N ₁ * p = 4p as shown in FIG. 11E. T = _{t 8} o'clock in FIG. 18C, for the first position in FIG. 18A, the recording medium is moved a _{7VΔt = (N 1 * N 2} -1) VΔt. t ₈ between (FIG. 18C) and _{t S} (FIG. 18D), the extra distance that the recording medium needs to be moved _{N 1 * p- (N 1 *} N 2 -1) VΔt = N 1 * p - a _{(N 1 * N 2 -1)} * (p-X 1). _{Therefore, after all N 1} * N ₂ droplet ejectors in each row of the first stroke are ignited and before the start of the second stroke, the delay time τ ₃ = t _S −t ₈ = (N ₁ * p− (N). _{1 * N 2 -1) * (} p-X 1)) requiring / V.

In the other method (not shown), the direction from the first ignition droplet ejector of the first set to the second ignition droplet ejector of the first set is opposite to the scanning direction 56, and the ignition order is the same as in FIG. 11B. (Direction 127) is held so that the relative moving direction of the recording medium is reversed. As described in FIG. 10, the sequencer 175 can be used in reverse ignition order, which is usually easier than reversing the moving direction of the medium, especially for single-pass printing.

Are opposite in direction scanning direction 56 from the first ignition droplet ejector of the first set to the second ignition droplet ejector of the first set, the scanning direction pitch p greater than the droplet ejector spacing X _1, its advantages Is to reduce the ink coverage. In other words, the ignition order shown in FIGS. 11A-11E and the moving direction of the recording medium can provide a higher resolution print mode, and the reverse ignition order shown in FIGS. 18A-18D provides an ink-saving printing mode. Can be provided. Other than that, the degree of diffusion is different in recording media of different types of ink. It is beneficial to make the points printed along the scanning direction 56 more adjacent to the recording medium having low ink diffusion depending on the ignition order and the moving direction of the recording medium shown in FIGS. 11A to 11E. It is beneficial to keep the points printed along the scanning direction 56 away from the recording medium with high ink diffusion by the reverse ignition order shown in FIGS. 18A-18D.

Also, although these embodiments are not described in detail here, it can be conceived that the cross mode is used in conjunction with the reverse ignition order. The crossing mode having such a reverse ignition order can provide a scanning direction pitch capable of realizing a crossing mode in which the scanning direction pitch is different from that shown in FIGS. 15A to 16E.

[0121] In the embodiment of the above printing method, the droplet ejectors in each row of each column are ignited at the same time. In another embodiment (not shown), the droplet ejectors in different sets of different columns ignite simultaneously, but there are no other simultaneously igniting droplet ejectors in the same column. Further, in the above embodiment, the droplet ejector set in one row is ignited in the order from left to right. In another embodiment (not shown), the droplet ejector sets in one column can be ignited in sequence in the column.

An inkjet printing system 1 as shown in FIG. 6 includes a printhead 50 having a two-dimensional array 150 of droplet ejectors 212, and a two-dimensional array 450 includes a set 120 of droplet ejectors 212 that are misaligned with each other. It has a plurality of droplet ejectors 212 that are basically aligned along the scanning direction 56, and the droplet ejectors 212 are fluidly communicated to a common ink source 290. In a printing method that describes the inkjet printing system 1 by a more general method, the image data is from the image data source 2, passes through the image processing unit 3 and the controller 4, and is provided to the inkjet print head 50 to provide the image data. It is to control whether or not to ignite when the droplet ejector 212 is activated by. During the ink droplet ejection period, the transfer mechanism 6 continuously advances the recording medium 62 with respect to the print head 50 along the scanning direction. The controller 4 and the addressing circuit 170 (FIG. 9) can simultaneously ignite the corresponding droplet ejector 212 in the set 120 of the first group. The controller 4 and the addressing circuit 170 (FIG. 9) can in turn ignite each droplet ejector 212 into each set 120 in the first group until each member of each set has a chance to ignite. The controller 4 and the addressing circuit 170 (FIG. 9) can simultaneously ignite the corresponding droplet ejector 212 of the second group set 120. The controller 4 and the addressing circuit 170 (FIG. 9) can sequentially ignite each droplet ejector 212 into each set 120 in the second group. The controller 4 and the addressing circuit 170 (FIG. 9) similarly do any other to the 2D array 150 until all the droplet ejectors in the 2D array 150 have a chance to ignite during the first stroke period. The set can be ignited continuously. In a subsequent stroke similar to the first stroke, the activation ignition process of the two-dimensional array of the droplet ejector 212 is continued, and at the same time, the recording medium 62 moves with respect to the print head 50 along the scanning direction 56 until printing is completed. , Print an image with ink from the common ink source 290 based on the image data.

In the description for FIGS. 6-9, the printhead chip 215 is composed of droplet ejectors of the same structure and includes a single two-dimensional array 150 that is part of the inkjet printhead 50 (FIG. 6). Using the ink in the first ink source 290, such a printhead chip 215 can perform monochromatic printing. As shown in FIG. 19, in another embodiment, the inkjet printhead 50 can include a printhead chip 216. The printhead chip 215 includes a first two-dimensional array 150 composed of a first droplet ejector and a second two-dimensional array 151 composed of a second droplet ejector, the second two-dimensional array 151 and the second. The two-dimensional array 150 of 1 is separated by the array spacing S along the first direction, that is, along the scanning direction 56. In some embodiments, the second two-dimensional array 151 is fluid communicated to a second ink source 291 that is different from the first ink source 290. For example, in the print head chip 216 used for color printing, the ink source 290 may be a blue-green ink, and the ink source 291 may be a magenta ink. The inkjet printhead 50 may further include another two-dimensional array (not shown), which is fluid communicated to the corresponding other ink sources such as yellow and black inks. These other two-dimensional arrays can be included in the same printhead chip 216, or in one single printhead chip.

Similar to the first two-dimensional array 150 in which the first droplet ejector 212 is configured, the second two-dimensional array 151 is composed of columns, rows and sets of second droplet ejector 213. The various printing methods are similar to the ignition of the first droplet ejector 212 of the first two-dimensional array 150, and the second droplet ejector 213 in the second two-dimensional array 151 is ignited by a stroke method. There should be a relative delay time S / V between the ignition stroke of the second droplet ejector 213 of the second array 151 and the ignition stroke of the corresponding first droplet ejector 212, and the recording medium should have a scanning direction. It moves at a speed V with respect to the printhead chip 216 along 56. By such a method, the droplets ejected by the second two-dimensional array 151 and the droplets ejected by the first two-dimensional array 150 can fall into the pixel grid at the same point position, and the image from the image source 2 can be printed. A color printed image is formed from the data (FIG. 6).

Fluidly connected to the second ink source 291 compared to the first droplet ejector 212 in the first two-dimensional array 150 that is fluidly connected to the first ink source 290 to provide the required nominal droplet volume for different inks. It is advantageous to have a structure different from that of the second droplet ejector 213 in the second two-dimensional array 151. For example, the diameter of the discharge hole can be different, the geometry of the pressure chamber can be different, or the driver sizes of the droplet ejectors 212 and 213 can be different.

As described in FIG. 6, the width of the two-dimensional arrays 150 and 151 along the scanning direction 56 is W, the length along the array direction 54 is L, and L is larger than W. It is advantageous that the length L is perpendicular and long in the scanning direction 56, and the ink droplets using the two ink sources 290 and 291 for single-pass printing or single-strip printing are more in the recording medium 62. Covers a large print area. In the color printhead, it is possible to determine from the droplet ejector array installation which dimension of the 2D array corresponds to the scan axis X and which dimension of the 2D array corresponds to the array axis Y. Different two-dimensional arrays print ink droplets at the same location on the recording medium and must be separated from each other along the scan axis X. Therefore, in a color printhead (without considering the transfer mechanism that provides the relative movement of the recording medium and the printhead), the width size W (length size L) of the two-dimensional array extends in the scanning direction 56. You can decide that.

In the prior art, it has a two-dimensional array installation of various droplet ejectors. In the prior art, FIG. 20 displays a droplet ejector array in Patent Document 6 and is described by FIG. 85 of the patent (array direction 54, scanning direction 56, length L and width W are already incorporated into FIG. 20). ). In the figure, some arrays 360 composed of inkjet ejection hole series 361-363 are displayed, and each series provides a single printing color (turquoise, magenta and yellow) and is used for color printing. The address circuit 364 and the connection pad 365 are further displayed in the figure. The color ejection holes 361-363 of each series include inkjet ejection holes 368 in which the positions of the two rows are arranged at intervals. At first glance, the installation of the droplet ejector in the predetermined discharge hole series (for example, the discharge hole series 361) seems to be similar to the installation as shown in FIG. In some arrays 360, each row in the two discharge hole columns of the discharge hole series 361 has three discharge hole groups, each group has five discharge holes, and the groups are staggered from each other. As described above, the discharge hole series 361-363 correspond to different colors and are separated from each other along the scanning direction 56. Therefore, the three discharge hole groups of the five discharge holes in each row do not stretch along the scanning direction 56, but stretch along the array method 504. (The width W of each discharge hole series does not extend along the scanning direction 56, but extends along the array method 504.) Therefore, the droplet ejectors in each group cooperate with the points along the scanning direction 56. Cannot print and form lines. A single ejection hole 368 within each group is responsible for printing all points in the print line along the scan direction 56. It can be clearly seen in FIG. 87 of Patent Document 6 that the purpose of using the two intersecting discharge holes 368 in each discharge hole series 361-363 is to provide higher print resolution along the array direction 54. can.

With reference to FIG. 19, in some embodiments, the second ink source 291 is the same as the first ink source 290, the ink droplet ejectors 212 and 213 have different structures and are different in size due to the same ink. Provides ink droplets. In other words, in order to realize grayscale printing, the first droplet ejector 212 can print small dots, and the second droplet ejector 213 can print large dots.

In these examples, the two-dimensional array of droplet ejectors needs to be long enough to stretch and traverse the recording medium, especially for page width printheads, and the required total liquid in the two-dimensional array. Placing the drop ejector on a single printhead chip is impractical. FIG. 21 shows the second printhead chip 217, which is basically the same as the first printhead chip 215, and the second printhead chip 217 is displaced from the position of the first printhead chip 215 along the array direction 54. , They join end-to-end along the butt edge 214. It should be noted that the term "end-to-end" here means a close adjacency between the two printhead chips and does not necessarily mean physical contact at the butt edge 214. The two-dimensional array 152 of the droplet ejector 212 includes the first two-dimensional array 153 and the two-dimensional array 154 of the droplet ejector which is basically the same, and the two-dimensional array 153 is installed on the first printhead chip 215. The two-dimensional array 154 is installed on the second printhead chip 217. Both the two-dimensional array 153 and the two-dimensional array 154 are installed so as to be fluid-connected to the first ink source 290. In the example shown in FIG. 21, set between the order to hold the spacing that matches along the array direction 54, set 120 the first is essentially uniform along the array direction 54 offset Y ₁ adjacent in each row 130 The second terminal set 192 of the two-dimensional array 154, which is basically the same as the first terminal set 191 of the first two-dimensional array 153, is spaced by the first two-dimensional array 153 along the array direction 54. basically it equal to the offset _{Y 1.}

FIG. 22 shows the second printhead chip 217, which is basically the same as the first printhead chip 215, and the second printhead chip 217 is displaced from the position of the first printhead chip 215 along the array direction 54. _{, A distance Y 0} from the first printhead chip 215. The two-dimensional array 152 of the droplet ejector 212 is basically the same two-dimensional array 154 of the droplet ejector installed on the first two-dimensional array 153 and the second printhead chip 217 of the first printhead chip 215. include. The droplet ejector 212 of the first printhead chip 215 includes an ink inlet, and the ink inlet is installed so as to be fluidly connected to the first ink source 290, and is basically the same as the droplet of the second printhead chip 217. The ejector 212 includes an ink inlet, and the ink inlet is installed so as to be fluidly connected to the second ink source 291. The second ink source 291 is different from the first ink source 290. The separated distance Y ₀ provides the required area and seals and separates the ink supply channels of the first printhead chip 215 and the second printhead chip 217.

FIG. 23 displays a pair of printhead chips 218 and 219, which are joined end-to-end along the butt edge 214 by a method similar to FIG. The printhead chips 218 and 219 include a first two-dimensional array 150 composed of a first droplet ejector and a second two-dimensional array 151 composed of a second droplet ejector, respectively, and a second two-dimensional array. 151 is separated into a first two-dimensional array 150 along a first direction, which is also a scanning direction 56. The first two-dimensional array 150 in each printhead chip 218 and 219 is fluidly connected to the first ink source 290. The second two-dimensional array 151 in each printhead chip 218 and 219 is fluidly connected to the second ink source 291. The second ink source 291 is different from the first ink source 290. Abutting edges 214 of the printhead chip 218 and the printhead chip 219 includes the features of the steps helps to hold the spacing Y ₁ between the set of top-end ink droplet ejectors of a two-dimensional array 150 and 151.

FIG. 24A displays a pair of printhead chips 511 and 512, which are end-to-end joined to the butt edge 214. The droplet ejector installation of the printhead chips 511 and 512 is similar to that shown in FIG. In the bottom set of columns 141, 142, 143 and 144, the bottom droplet ejector 111s are all arranged along the array direction 54. During the outermost edge of the most adjacent droplets ejectors of the printhead chip 511 and 512 have a gap G _1. To provide space for any electronics or other components adjacent to the edge 214, and to allow to have a smaller spacing between adjacent abutting edges 214, the method can be selected increases the gap G _1, at the same time it is to keep the distance Y ₁ between the two droplet ejectors adjacent sets of top end of the print head chip 511 and 512.

FIG. 24B displays a pair of printhead chips 521 and 522, which are end-to-end joined to the butt edge 214. In the two-dimensional ejector array formed on each printhead chip 521 and 522, columns of adjacent ink droplets ejector is displaced the distance X ₁ along the scanning direction 56. As a result, the droplet ejector 112 in the column 141 is aligned with the droplet ejector 111 in the column 142, the droplet ejector 112 in the column 142 is aligned with the droplet ejector 111 in the column 143, and in the column 143. The droplet ejector 112 is aligned with the droplet ejector 111 in column 144. Along the scan direction 56, the distance _{X 6} between the droplet ejector 111 and drop ejector 111 in the last column 144 in the first column 141 _{X 6 = 3X 1 = (N} 4 -1) * X It is _{1. As can be seen from FIG. 24B, there is a gap G 2} between the outermost edges of the most adjacent droplet ejectors of the printhead chips 521 and 522, where G ₂ is the most adjacent of the printhead tips 511 and 512 in FIG. 24A. during the outermost edge of the droplet ejectors it is greater than the gap G _1. The gap G ₂ increases with the increase of X _6. The difference between G ₁ and G ₂ does not appear large in FIGS. 24A and 24B, and the number of columns is N ₄ = 4, but for a printhead chip with a higher number of columns, G ₁ and G ₂ The difference between them is greater. Further, columns of the displacement adjacent in FIG. 24 is X _1. More broadly, the displacement of the column adjacent may be m * _{X 1,} m is an integer, thus _{X 6 = m * (N 4} -1) is * _{X 1.}

FIG. 25 displays a pair of printhead chips 531 and 532, which are end-to-end joined to the butt edges 533 and 534, respectively. Unlike the embodiment of the linear butt edge 214, the butt edges 533 and 534 include steps 536 and 535, respectively. Each printhead chip 531 and 532 has a left butt edge 534 and a right butt edge 533, the left butt edge 534 has a step 535 projecting to the left, the width of the step is w, and the right butt edge. The portion 533 has a step 536 that is recessed to the left, and the width of the step is w. The steps of the butt edge 533 of the printhead chip 531 and the butt edge 534 of the printhead chip 532 can be positioned in a manner that basically complements the butt edges of the printhead chips 531 and 532. Such schemes between the top end ink droplet ejectors two sets of print head chips 531 and 532 by holds interval Y _1. Steps 535 and 536 shown in FIG. 25 have right angles, but in practice the corners of the steps may be circular in practice to avoid stress concentration, which stress concentration can result in structural weaknesses. ..

For example, many printhead chips are usually manufactured together on a single silicon wafer. After the wafer processing is complete, each printhead chip must be separated from the wafer. The printhead chip and the wafer can be separated by cutting the printhead chip having a straight side. However, when the sides of the printhead chip are stepped, some of these steps are cut when cutting, as shown in FIGS. 23 and 25. A method of accurately forming steps 535 and 536 is to use an etching process, for example silicon deep reactive ion etching can provide feature etching of the wafer, with an accuracy of on the order of micron. Another exact method of forming steps 535 and 536 is to use a laser cutting process.

FIG. 26 illustrates an example of the roll-to-roll printing system 80. The roll-to-roll printing system 80 can use the printhead 50 and has one or more two-dimensional arrays of the droplet ejectors described in the above embodiment. The fixed inkjet printhead 50 is fluidly connected to the first ink source 290. The recording medium 62 roll advances from the feed roll 81 to the receiving roll 82 along the scanning direction 56, and is guided by one or more roll shafts 83. The relative movement direction between the recording medium 62 and the print head 50 is kept constant during the entire printing process. When the color printhead shown in FIG. 22 is used, it has a plurality of two-dimensional arrays and is fluidly connected to different ink sources, and the relative movement between the recording medium 62 and the printhead 50 is in a single direction. This means that the order of different colors in one-pass printing is always the same. For example, the droplet ejector in the two-dimensional array 150 always prints the ink of the first ink source 290 first, and the droplet ejector in the two-dimensional array 151 prints the ink of the second ink source 291. Keeping the same color print order is beneficial in providing a more matching visual image. The print head 50 is long enough to traverse the roll width of the recording medium 62, or at least traverses the roll width of the print portion of the recording medium 62.

FIG. 27 illustrates an example of a sliding frame printing system 90, wherein the sliding frame printing system 90 can use a printhead 50 and may use one or more droplet ejectors according to the above embodiment. Has a two-dimensional array of. As mentioned above, the two-dimensional array has a length L along the array direction 54. The sliding frame (not shown) moves the printhead 50 along the sliding frame path 91. In the first pass printing, the sliding frame moves the printhead 50 forward along the direction 92, while the droplet ejector prints the first strip on the recording medium 62. The recording medium 62 is advanced to the upper end and is represented by the medium advance 94. In the second pass printing, the sliding frame moves the printhead 50 along the reverse direction 93, while the droplet ejector prints the second strip. Therefore, the image is printed on the recording medium 62 by a continuous two-way print strip. In two-way printing, the scanning directions for each contiguous strip should be reversed. As described in FIGS. 11A-11E and 18A-18D, it is the ignition sequence that _{the scan direction pitch p is greater than or less than the ejector spacing X1 and is between the first and second ejectors in the ignitable set.} The direction 127 is the same as the scanning direction, or the direction 128 between the first ejector and the second ejector in the set that can be ignited is opposite to the scanning direction. The ignition order must be reversed for each contiguous strip in order to keep the bidirectional sliding frame printing system 90 that the scanning pitch does not change between the strips. You can choose to partially stack consecutive strips. The advantage of using the two-dimensional array type described in the above embodiment is that a plurality of ejection holes in each set co-print any predetermined linear pixel on the recording medium 62 parallel to the sliding frame path 91. Is. Therefore, it is not necessary to cover the printing defect with a large amount of overlap between adjacent strips. A small stack in the strip can be selected to obscure the offset in the medium advance 94. The sliding frame printing system in the prior art uses multiple pass printing to achieve high quality printing, and by stacking smaller strips, faster print output can be achieved.

When the color printhead shown in FIG. 23 is used in the two-way inkjet printing system 90, the sliding frame drives the printhead 50 to move first in the front direction 92 and then in the opposite direction 93, adjacent to each other. It results in a different color printing order within the strip, so the resulting color offset may need to be corrected by adjusting the image. For example, a turquoise dot in the forward direction 92 can be printed on a turquoise dot, and a turquoise dot in the opposite direction 93 can be printed on a turquoise dot, thereby different colors. Is displayed. Some prior art printheads have a mirror-symmetrical color droplet ejector arrangement. For example, a three-color mirror-symmetrical printhead may have five droplet ejector arrays, including a central yellow array, two adjacent red-purple arrays, and two outer blue-green arrays. An embodiment can be envisioned by the droplet ejector of FIG. 7, where the distance X ₅ between the rows of two adjacent droplet ejectors stores one droplet ejector array rather than a size of 2 X _1. The second color ink can be printed, and the droplet ejector rows on both sides print the first color ink.

When the color printhead shown in FIG. 22 is used in the two-way inkjet printing system 90, there is no need to adjust the image to correct the color offset, and the sliding frame has the sliding frame in which the printhead 50 first moves in the forward direction 92 and then. It is driven to move in the opposite direction 93, and the color printing order in the adjacent strips does not change.

In the above examples, at least some of the examples are described and displayed in an ideal format. For example, in FIG. 7, the droplet ejectors 111-114 of the set 121 are perfectly aligned along the scanning direction 56. In the real world, when we say that the droplet ejectors in each set are basically aligned along the scanning direction, a small offset from perfect alignment is also taken into account. Similar to FIG. 7, FIG. 28A displays the droplet ejectors 111-114 of the set 121 and the droplet ejectors 115-118 of the set 122, which are perfectly aligned along the scanning direction 56. In other words, line 551 along the scanning direction 56 penetrates the center of all droplet ejectors 111-114 of set 121, and line 552 along scanning direction 56 is line 551 centered on all droplet ejectors 115-118 of set 121. Penetrate. The lines 552 are arranged along the array direction 54 on the line 551 at a first offset. FIG. 28B shows the droplet ejector sets 111-114 of the set 121 that are perfectly aligned along the scanning direction 56 and the droplet ejector sets 115-118 of the set 122 that are not fully aligned along the scanning direction 56. indicate. The best fit line 550 along the scanning direction penetrates the center of the droplet ejectors 115 and 117. However, the center of the droplet ejector 118 is shifted to the left side of the best-fit line 550 by the displacement Y _D, the center of the droplet ejector 116 is shifted to the right of the best-fit line 550 by a displacement similar. Such displacements can depend on manufacturing tolerances, or they can be intentionally designed. In some embodiments, the droplet ejector manufactured using the photoetching and microelectronics manufacturing methods can have a position accuracy of about 1 micron class. In some embodiments, the first offset _{Y 1} may be 1/1200 inch or about 21 microns. In such an embodiment, manufacturing tolerances will allow the droplet ejectors are aligned by the first within 10% accuracy of the offset Y ₁ along the scanning direction 56. In another embodiment, a constant amount of droplet ejector alignment offset is designed to mask the effects of directional offsets so that even a perfectly aligned droplet ejector is perfectly aligned with the recording medium 62. Cannot be printed. The fact that the droplet ejectors in the set are basically aligned along the scanning direction in the text means that the droplet ejectors in the set are displaced from generation to generation with respect to the best fit line in the array direction. Y _D is half of the first offset Y _1. Smaller. For example, the straightness of the line 351 in FIG. 13 is determined by the part to small maximum displacement, preferably maximum displacement Y _D is less than 0.3Y ₁ In some embodiments, in other embodiments, the maximum It is more preferable that the displacement Y _D is _{smaller than 0.2 Y 1.} The so-called best fit line can usually be calculated by a variety of methods, for example a linear regression method fitted by the least squares method. FIG. 28C displays a linear regression line 553 that penetrates the centers of the two droplet ejectors 554 and 555. Since the linear regression line 553 is not parallel to the scanning direction 56, the linear regression line 553 is not the best fit line along the scanning direction 56 in the text. The best fit line 550 in FIG. 28C extends along the scanning direction 56. Further, the best fit line 550 is defined here as the sum of the displacements of the droplet ejector with respect to the best fit line 550 is zero. In a simple example shown in FIG. 28C, the sum of the displacement is such that 0, the center of the droplet ejector 554 has a displacement of -Y _D to best-fit line 550, the center of the droplet ejectors 555 best fit to line 550 having a displacement of + _{Y D.}

Hereinafter, other uses of "basically" in the text will be described. The droplet ejectors in each set here are arranged uniformly spaced by essentially distance X ₁ along the scanning direction 56, the spacing distance of the droplet ejectors adjacent in the set X ₁ It means that it is located within the range of ± 20%. Adjacent sets in each row here are basically uniformly arranged along the array direction 54 with a first offset Y ₁ so that the spacing distances of the adjacent sets are in the range of Y ₁ ± 20%. Means to be inside. As similar to, the first of the first top end set and the second most distal set a distance equal to essentially first offset Y ₁ along the array direction of the second two-dimensional array of two-dimensional array here The fact that they are arranged at intervals means that the distance at which they are arranged at intervals is _{within the range of Y 1} ± 20%.

The fact that the first printhead chip here is basically the same as the second printhead chip means that their designs are the same, but there may be differences due to their manufacturing tolerances. Similarly, the fact that one 2D array here is essentially the same as the other 2D arrays means that their designs are the same, but there are differences due to their manufacturing tolerances. there is a possibility. The step at the first edge of the first printhead chip and the step at the adjacent edge of the adjacent second printhead chip are basically positioned in a complementary manner so that the two edges complement each other. It means that the deviation that fits each other is smaller than 20% of the step width w.

The fact that the recording medium here moves with respect to the printhead at a basically constant speed V along the scanning direction means that the recording medium moves at a speed within the range of V ± 20% during the period of ejecting the droplets. It means passing through a fixed printhead, or the printhead moving at a speed within the V ± 20% range and passing through a fixed recording medium.

The text has described the invention in detail by special reference to some preferred embodiments of the invention, but is included in the modifications and modifications made within the spirit and scope of the invention.

Claims (13)

Inkjet print head
Contains a two-dimensional array of droplet ejectors arranged by multiple columns containing multiple rows, each containing multiple sets containing multiple droplet ejectors.
All droplet ejectors in each row are all members of multiple sets in that row, all droplet ejectors in each set are basically aligned along the first direction, and the set in each row is in the first direction. They are spaced apart from each other along the first direction and offset from each other along the second direction, and the rows in each column are spaced apart from each other along the first direction and offset from each other along the second direction. The columns are offset from each other along the second direction, the two-dimensional array has a width W along the first direction, a length L greater than W along the second direction, and a two-dimensional array. Each droplet ejector in
Discharge hole and
Ink inlets installed so that fluids communicate with a common first ink source,
A pressure chamber with fluid communication to the discharge hole and ink inlet,
An inkjet printhead characterized by including a driver installed to selectively pressurize the pressure chamber so that ink is ejected from the ejection holes. The droplet ejectors in each set are basically evenly arranged at intervals X1 along the first direction.
Along the first direction, the spacing between the most adjacent droplets ejectors adjacent sets in one row equal to X _1,
Before SL along the first direction, the spacing between the most adjacent droplets ejector of the second row adjacent to the first row in the column is greater than X1, leads between the first and second row The inkjet print head according to claim 1, which is installed between them. Inkjet print head
Contains a two-dimensional array of droplet ejectors arranged by multiple columns containing multiple rows, each containing multiple sets containing multiple droplet ejectors.
All droplet ejectors in each row are all members of multiple sets in that row, all droplet ejectors in each set are basically aligned along the first direction, and the set in each row is in the first direction. They are spaced apart from each other along the first direction and offset from each other along the second direction, and the rows in each column are spaced apart from each other along the first direction and offset from each other along the second direction. The columns are offset from each other along the second direction, the two-dimensional array has a width W along the first direction, a length L greater than W along the second direction, and a two-dimensional array. Each droplet ejector in
Discharge hole and
Ink inlets installed so that fluids communicate with a common first ink source,
A pressure chamber with fluid communication to the discharge hole and ink inlet,
Includes a driver installed to selectively pressurize the pressure chamber so that ink is ejected from the ejection holes.
Droplet ejectors in each set are arranged essentially evenly spaced X ₁ along a first direction, column adjacent in the 2-dimensional array is displaced by a distance m * X1 along the first direction, m Is an integer
An inkjet print head that features that. The two-dimensional array is the first two-dimensional array of the first droplet ejector, at least the second of the first two-dimensional array and the second droplet ejector separated along the first direction. The inkjet printhead according to claim 1, further comprising a two-dimensional array. Inkjet print head
Contains a two-dimensional array of droplet ejectors arranged by multiple columns containing multiple rows, each containing multiple sets containing multiple droplet ejectors.
All droplet ejectors in each row are all members of multiple sets in that row, all droplet ejectors in each set are basically aligned along the first direction, and the set in each row is in the first direction. They are spaced apart from each other along the first direction and offset from each other along the second direction, and the rows in each column are spaced apart from each other along the first direction and offset from each other along the second direction. The columns are offset from each other along the second direction, the two-dimensional array has a width W along the first direction, a length L greater than W along the second direction, and a two-dimensional array. Each droplet ejector in
Discharge hole and
Ink inlets installed so that fluids communicate with a common first ink source,
A pressure chamber with fluid communication to the discharge hole and ink inlet,
Includes a driver installed to selectively pressurize the pressure chamber so that ink is ejected from the ejection holes.
It further comprises at least one first chip and a second chip that is essentially the same as one first chip that is displaced from the first chip along the second direction.
The two-dimensional array is basically the same as one first two-dimensional droplet ejector array installed on the first chip and the first two-dimensional droplet ejector array installed on the second chip. Including one two-dimensional droplet ejector array
Each droplet ejector in the two-dimensional array, which is basically the same as the first two-dimensional droplet ejector array installed on the second chip, is an ink inlet installed so as to be fluid-communication with the first ink source. including
An inkjet print head that features that. Inkjet print head
Includes a two-dimensional droplet ejector array consisting of multiple columns arranged with multiple rows, each containing multiple sets containing multiple droplet ejectors.
All droplet ejectors in each set are basically aligned along the first direction, the sets in each row are spaced apart from each other along the first direction and offset from each other along the second direction. , The droplet ejectors in each set are basically evenly arranged at a distance X1 along the first direction, and the distance between the most adjacent droplet ejectors between adjacent sets in the same row along the first direction is X1. equal rows in each column is empty only by sequence apart from each other along the first direction and displaced from each other along the second direction, columns are displaced from each other along the second direction, the two-dimensional array Each droplet ejector in the two-dimensional array has a width W along the first direction and a length L greater than W along the second direction.
Discharge hole and
Ink inlets installed so that fluids communicate with a common first ink source,
A pressure chamber with fluid communication to the discharge hole and ink inlet,
An inkjet printhead characterized by including a driver installed to selectively pressurize the pressure chamber so that ink is ejected from the ejection holes. Inkjet print head
Includes a two-dimensional droplet ejector array consisting of multiple columns arranged with multiple rows, each containing multiple sets containing multiple droplet ejectors.
The droplet ejectors in each set are basically aligned along the first direction, the sets in each row are spaced apart from each other along the first direction, offset from each other along the second direction, and each row. the adjacent sets essentially uniformly spaced at a first offset in a second direction air only being arranged, row closest to adjacent sets in each column in the first offset in the second direction in are arranged apart air only, the columns are displaced from each other along the second direction, is between the second set of columns adjacent to the first set and the first column in the first column, along the second direction The minimum spacing is equal to the first offset, the two-dimensional array has a width W along the first direction, a length L greater than W along the second direction, and each droplet ejector in the two-dimensional array ,
Discharge hole and
An ink inlet installed so that fluid can communicate with the first ink source,
A pressure chamber with fluid communication to the discharge hole and ink inlet,
An inkjet printhead characterized by including a driver installed to selectively pressurize the pressure chamber so that ink is ejected from the ejection holes. A drive circuit that is connected to the driver of each droplet ejector and activates the driver,
Further includes an addressing circuit, which selectively activates the driver for the droplet ejector through the drive circuit.
The addressing circuit comprises a plurality of address lines, each droplet ejector in one line is connected to a different address line of the addressing circuit, and each address line of the addressing circuit is a corresponding position in each set in each line. Connected to one droplet ejector
The inkjet print head according to claim 1. Each of the second droplet ejectors includes an ink inlet installed so as to allow fluid communication to a second ink source different from the first ink source.
The inkjet print head according to claim 4. The structure of the second droplet ejector is different from the structure of the first droplet ejector.
The inkjet print head according to claim 4. The two-dimensional array is a first two-dimensional array of first droplet ejectors, the first chip and the second chip further include a second two-dimensional array of second droplet ejectors, said second. The two-dimensional array is separated from the first two-dimensional array along the first direction, and each second droplet ejector in the second two-dimensional array communicates fluidly with a second ink source different from the first ink source. Including the ink inlet installed to be
The inkjet print head according to claim 5. Adjacent sets within each row are essentially uniformly and spaced along the second direction with a first offset and are essentially the same as the first terminal set of the first two-dimensional array. The second terminal set of a two-dimensional array is spaced along the second direction at a distance essentially equal to the first offset.
The inkjet print head according to claim 5. A method in which the first edge portion of the first chip and the adjacent second edge portion of the second chip include a step, and the step at the first edge portion and the step at the second edge portion basically complement each other. Positioned by
The inkjet print head according to claim 12.

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