JP2015089624A - Inkjet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head capable of outputting an image in which density unevenness due to driving order of block driving and density unevenness due to an ink channel direction are less noticeable, even in a midst of recording operation.SOLUTION: In an inkjet head comprising a plurality of tips that changes amount of discharge depending on a position in an arrangement direction of a recording element when the same energy is applied, a plurality of channels is prepared for moving ink while sequentially supplying the ink to the plurality of tips. At this time, the plurality of tips is arranged in a direction in which a moving direction of the ink in the channel to the arrangement direction becomes the same between the plurality of tips.

Description

  The present invention relates to an inkjet head including a plurality of recording elements that discharge recording liquid such as ink in accordance with a recording signal for the purpose of recording an image.

  An ink jet head that applies a voltage pulse to a heating resistor provided in each recording element according to recording data and ejects ink using the generated thermal energy can output an image with high definition and high speed. Widely useful. In particular, a recording apparatus equipped with a full-line inkjet head in which a plurality of recording elements are arranged at a high density by a distance corresponding to the width of the recording paper has been rapidly popularized in recent years because it enables higher-speed output. ing. In such a long inkjet head, in order to improve the manufacturing yield, a plurality of chips each having a smaller number of recording elements are arranged in the width direction of the paper. There are many.

  In such an inkjet head having a large number of recording elements, the discharge amount may vary between the recording elements due to manufacturing errors of individual chips. Also, the ejection amount varies with time depending on the usage frequency of each printing element. Furthermore, the ejection amount of each recording element is also affected by the wiring configuration and application method for applying a voltage pulse to the heating resistor provided in each recording element. Such a variation in the discharge amount in the ink jet head may cause density unevenness in the output image.

  In Patent Document 1, a predetermined measurement chart is recorded on an inkjet head for density unevenness generated in the head, and the density of the output measurement chart is read to calculate a correction value for each nozzle (recording element). A method is disclosed. According to Patent Document 1 as described above, by correcting the recording data for each nozzle based on the respective correction values, it is possible to reduce the density variation between the nozzles and output a uniform image. .

  Further, in Patent Document 2, an ink inlet and an outlet are provided to the inkjet head in order to suppress an increase in the discharge amount accompanying the temperature rise of the inkjet head, and each recording element is directed from the inlet to the outlet. In other words, a configuration in which ink is supplied from ink that flows in this manner is disclosed. Usually, the discharge amount of each recording element tends to increase according to the temperature of ink in the vicinity of the heating element. As in Patent Document 2, if the ink supplied to the heat generating element is constantly flowing, the temperature rise of the ink in the vicinity of the heat generating element can be suppressed, and the increase in the discharge amount can also be suppressed.

JP-A-2005-59351 JP 2009-961 A

  By the way, in a long inkjet head configured to drive a heating element and eject ink, there is a concern that a large voltage drop may occur if a large number of heating elements are energized at once. Therefore, in general, a plurality of recording elements arranged on one chip are often divided into a plurality of groups and driven at different times. However, in such block driving, the total energy applied to the individual recording elements may change step by step depending on the driving order. In other words, when block driving is performed in which a plurality of recording elements are divided and driven along the arrangement direction, the ejection amount changes depending on the position in the arrangement direction in the chip. The difference in applied energy appears as a difference in ejection amount, and the difference in ejection amount appears as a density difference on the paper.

  On the other hand, the configuration adopting Patent Document 2 has an effect of suppressing the temperature rise of individual heating elements and the entire inkjet head, but the temperature of the ink tends to gradually increase in the path from the inlet to the outlet. It is in. Therefore, the temperature of the supplied ink varies depending on the position of the chip disposed in the ink jet head and the position where the individual recording elements are disposed in the same chip. Specifically, the discharge amount of the recording element arranged on the downstream side of the recording element upstream of the ink flow path is larger, and the image density tends to be higher on the downstream side than on the upstream side of the chip. There is.

  However, the density unevenness due to the block driving order as described above and the density unevenness due to the ink flow path direction are greatly affected by the real-time ejection frequency of the inkjet head. For this reason, it is easy to change during the recording operation, and there are cases in which the method as in Patent Document 1 cannot cope with it.

  The present invention has been made to solve the above problems. Therefore, the object is to provide an inkjet that can output an image in which density unevenness due to the drive order of block drive and density unevenness due to the ink flow path direction are not noticeable even during the recording operation. Is to provide a head.

  For this purpose, the present invention arranges recording elements for ejecting ink by applying energy in a predetermined direction, and ejects ink with a constant tendency according to the position of the recording element in the predetermined direction when equal energy is applied. An ink-jet head having a plurality of chips whose amount changes, and a plurality of flow paths for moving ink while sequentially supplying ink to the plurality of chips, wherein the flow path with respect to the predetermined direction The direction of ink movement in the plurality of chips is the same.

  According to the present invention, it is possible to obtain a high-quality image in which density unevenness is hardly visually recognized.

1 is a perspective view of a full line type inkjet head H applicable to the present invention. 2 is an exploded perspective view of an inkjet head H. FIG. FIG. 3 is an exploded perspective view for explaining the configuration of the flow path member 1. FIG. 4 is a perspective view showing an ink flow in the flow path member 1 shown in FIG. 3. (A) And (b) is a figure which shows one chip | tip and its sectional drawing. It is the schematic for demonstrating the wiring structure with respect to a chip | tip. It is a timing chart of various signals. It is a figure which shows the mode of the recording element arranged on a chip | tip, and the dot recorded. (A) And (b) is a figure which shows the discharge amount fluctuation | variation in a chip | tip. (A) And (b) is a figure which shows the arrangement | positioning state of a chip | tip, and discharge amount fluctuation | variation. It is a figure which shows the arrangement | positioning state of the chip | tip in Example 2, and discharge amount fluctuation | variation.

  FIG. 1 is a perspective view of a full-line type inkjet head H applicable to the present invention. Here, 18 chips 2 are arranged as shown. In each of the chips 2, a plurality of recording elements that discharge ink in the z direction are arranged at a predetermined pitch in a predetermined direction (here, the x direction). By arranging 18 chips 2 so that the array of recording elements is continuous in the x direction while providing an area d overlapping in the y direction as shown in the figure, an ink jet head having a recording width w is defined. . The same ink is ejected from one inkjet head H. A desired image can be recorded on the recording paper by transporting the recording paper in the y direction intersecting the x direction with the ink jet head H fixed.

  FIG. 2 is an exploded perspective view of the inkjet head H. FIG. The inkjet head H mainly includes a flow path member 1 for supplying ink to individual recording elements, a chip 2 on which a plurality of recording elements are formed, a flexible wiring board 3 for transmitting an electrical signal to the chip 2, and a flow path member. 1 is composed of an ink supply unit 4 for supplying ink to 1. The ink supply unit 4 includes two members having the same shape, and includes an ink inlet 41 and an ink outlet 42 for the main tank, and an ink outlet 43 and an ink inlet 44 for the flow path member 1, respectively. The ink inlet 41 and the ink outlet 42 are connected to a main tank provided in the recording apparatus main body through a pump, and the ink outlet 43 and the ink inlet 44 are provided in the flow path member 1. Connected to the ink inlet and the ink outlet. With such a configuration, new ink can be fluidly supplied from the ink inlet 41 via a filter (not shown) while collecting ink that has not been ejected from the flow path member 1 from the ink outlet 42. ing.

  FIG. 3 is an exploded perspective view for explaining the configuration of the flow path member 1. The flow path member 1 is composed of a five-layer laminate of alumina as shown in the figure. The first layer is a layer for flowing ink into and out of the ink supply unit 4. Two ink inlets 111 and 113 for connection with the ink outlet 43 of the ink supply unit 4 and two ink outlets 112 and 114 for connection with the ink inlet 44 of the ink supply unit 4 are provided. ing. The second layer is a layer in which the auxiliary flow path 13 divided into four blocks is formed. Newly supplied ink or recovered ink that has not been ejected by the recording element moves along the sub-channel 13 formed in parallel to the xy plane. The third layer is a layer that connects the sub flow path 13 and the main flow path 14. Port for connecting the position corresponding to the upstream end and the downstream end of the sub-flow path 13 formed in the second layer and the position corresponding to the upstream end and the downstream end of the main flow path 14 formed in the fourth layer Is formed. The fourth layer is a layer in which the main channel 14 is formed. Two main flow paths 14 centering on the approximate center of the flow path member 1 are formed point-symmetrically. The ink supplied from the upstream end of the main flow path 14 positioned substantially at the center of the flow path member 1 flows in the left-right direction through the two main flow paths 14, and from the downstream ends positioned at the left and right ends of the flow path member 1, It is collected into the flow path 13. The fifth layer is a layer in which the distribution channel 15 is formed. Referring to FIG. 2 again, the distribution flow path 15 is arranged corresponding to the position of the 18 chips 2 in the inkjet head H, and supplies ink to each chip 2. The two main flow paths 14 in the fourth layer have zigzag paths to supply nine inks in order to the 18 distribution flow paths 15 that are alternately arranged in this way. .

  FIG. 4 is a perspective view showing the flow of ink in the flow path member 1 shown in FIG. The ink that has flowed in from the ink supply unit 4 through the ink inlets 111 and 113 moves to the approximate center of the inkjet head H by the two sub-channels, and is supplied to the main channel 14 respectively. In the main channel 14, these inks flow away from each other in the left-right direction, and are collected again in the sub-channel 13 at both ends (right end and left end).

  5A and 5B are views showing one of the chips 2 used in the present embodiment and a cross-sectional view thereof. Referring to FIG. 5A, on the surface of the chip 2, recording element arrays 24 in which a plurality of recording elements 20 are arranged so as to be continuous at a predetermined pitch in the x direction are further arranged in four lines in the y direction. They are arranged in parallel. The chip 2 has a configuration in which the nozzle member 21 is stacked on the element substrate 22. An alignment mark 23 is formed on the surface end of the chip 2 as a mark when positioning the chip 2 on the flow path member 1.

  FIG.5 (b) is AA sectional drawing of the figure (a). In the element substrate 22, an ink supply port 22 for supplying the ink supplied from the flow path member 1 to each recording element array 24 is formed for each recording element array 24. Individual recording elements 20 are formed on the nozzle member 21. In the present embodiment, one recording element 20 includes an ink path 211, a foaming chamber 212, and a heating resistor 221. The ink supplied from the ink supply port 222 is guided to the ink path 211 from the foaming chamber 212 corresponding to each recording element, and forms a meniscus in the vicinity of the discharge port. When the heating resistor 221 is applied according to the recording data, film boiling occurs in the ink in the foaming chamber 212, and the ink in the ink path is ejected from the ejection port by the growth energy of the generated bubbles. The ink consumed for this ejection is newly replenished from the ink supply port.

  Returning again to FIG. When 18 chips 2 having the above-described configuration are arranged at predetermined positions of the flow path member 1 as shown in the figure, the flexible wiring board 3 on the sheet having holes is further covered at the positions of the individual chips 2. The ink jet head H is completed. Wiring for supplying power and recording signals to the individual chips 2 is formed on the flexible wiring board 3, and its end 31 is connected to the electric board of the recording apparatus main body.

  By the way, in this embodiment, since the chip 2 performs the discharge operation using the thermal energy applied from the heating resistor 221, the discharge operation continues. Therefore, heat gradually accumulates in the chip 2. At this time, referring again to FIG. 4, the temperature of the heat of each chip 2 is suppressed by the ink supplied from the distribution flow path 15. Heat from the chip 2 is conducted through the path 15. The greater the number of ejections in the chip 2, the greater the amount of heat. Then, the temperature of the ink flowing in the main flow path 14 in order of the chip 9 and the chip 8... Gradually increases from the upstream end (chip 9) to the downstream end (chip 1). Usually, even when the same drive voltage is applied to the heating resistor 221, it is known that bubbles grow larger and the ejection amount increases as the ink temperature increases. That is, the discharge amount of the chip located on the downstream side is larger than the discharge amount of the chip located on the upstream side with respect to the main flow path 14. In order to cope with such a situation, in the present embodiment, in the two main flow paths 14, the length of the flow paths, that is, the number of chips supplying ink is set to the same number (9 pieces each), and the distance between the two flow paths is reduced. The ink temperature difference is suppressed as much as possible. In addition, since there is a concern that the temperature difference between the two main flow paths and the difference in the discharge amount will increase as the process proceeds downstream, the position of the ink inlet (upstream end) to which ink of the same temperature is supplied is set at the center in the x direction. Provided to prevent extreme density differences from being adjacent to each other on the image.

  Further, such a deviation in the discharge amount with respect to the flow path direction (x direction) also exists in each of the chips 2. Even in the same chip, the recording element located on the downstream side with respect to the recording element located on the upstream side with respect to the main flow path 14 is supplied with higher temperature ink and the discharge amount is also increased.

  On the other hand, as already described in the section of the background art, when the block drive is adopted for the chip 2, a phenomenon occurs in which the discharge amount varies depending on the position in the x direction in the chip 2. This will be specifically described below.

  FIG. 6 is a schematic diagram for explaining a wiring configuration for one chip 2. Here, a plurality of heating resistors are divided into seven blocks, and a wiring configuration for the heating resistors 302a to 302g included in each block is shown. The current to each of the heating resistors 302a to 302g is supplied by energizing the VH maintaining a predetermined voltage and the ground GNDH. At this time, the timing of energization, that is, the timing of switching on / off of each transistor 303 is different for the seven blocks. Specifically, the heat enable signal generated by the HE generation circuit (not shown) is delayed by seven stages A to G by the delay circuit 301 and input to the respective AND circuits 304-a to 304-g. . In addition to the heat enable (HE) signal, the AND circuits 304-a to 304-g receive the recording data latched by the data latch circuit and the signal from the time division logic circuit, and all the signals are input. The heating element 302 is energized with timing.

  FIG. 7 is a timing chart of various signals. In the present embodiment, delay signals are generated in the order of HE-g, HE-f... HE-a with respect to the HE signal generated by the HE generation circuit. The action is executed. In the figure, VH represents a voltage waveform of VH, GNDH represents a voltage waveform of GNDH, and IH represents a current waveform of a current flowing through VH.

  Here, the period t1 is a period in which energization to the seven heating resistors is started in order, and the value of IH gradually increases. At the time of the rise of IH, ringing as shown in the figure is caused in VH and GNDH due to the influence of parasitic inductance caused by IH flowing through the drive power supply wiring. Specifically, undershoot occurs in the VH voltage waveform, and overshoot ringing occurs in the GNDH voltage waveform. For this reason, the voltage applied to both ends of the heating resistor in the period t1 is lower than that in the period t2, and the current flowing through the heating resistor is also reduced.

  On the other hand, the period t3 is a period in which energization to the seven heating resistors is sequentially terminated, and the value of IH gradually decreases. When IH falls, ringing is caused in VH and GNDH due to the influence of parasitic inductance caused by IH flowing through the drive power supply wiring. Specifically, undershoot occurs in the VH voltage waveform, and overshoot ringing occurs in the GNDH voltage waveform. For this reason, the voltage applied to both ends of the heating resistor in the period t3 is higher than that in the period t2, and the current flowing through the heating resistor is also increased.

  That is, among the heating resistors 302-a to 302-g, the energy generated by the heating resistor 302-g that is driven first is the smallest, and the energy generated by the heating resistor 302-a that is driven last is the least. Become the largest. As a result, the ink ejection amount of the recording element including the heating resistor 302-g that is driven first is the smallest, and the ink ejection amount of the recording element including the heating resistor 302-a that is driven last is the largest.

  FIG. 8 is a diagram showing the recording elements arranged on the chip and the dots recorded by the individual recording elements on the paper surface. The size of dots recorded in the same block is substantially the same, but the size of dots recorded in different blocks is different from each other. In the inkjet head H of the present embodiment, the blocks are divided into A to G with respect to the arrangement direction (x direction) of the recording elements, and are driven in the order from G to A. Therefore, the dot recorded in the block G recorded on the right side of the figure is the smallest, and the dot increases as it moves to the left side. That is, the area recorded at the right end of the chip is thin, and the area recorded at the left end of the chip is dark, and the density difference occurs with a certain tendency according to the position of the recording elements in the arrangement direction. Even when a plurality of the above-described blocks A to G are provided in one chip, the density difference is generated with a certain tendency according to the position of the recording elements in the arrangement direction. For example, the chip drive may be divided into two at the center of the chip, and two blocks A to G described above may be provided in the chip.

  As described above, the long inkjet head H employed in the present embodiment includes density unevenness due to the block driving order and density unevenness due to the ink flow path direction in each chip. And any of these density unevenness has directionality in the feature in the chip. In other words, the density gradually increases or decreases with respect to the arrangement direction of the recording elements. Furthermore, such a feature shows a similar constant trend for all chips under the same conditions.

  FIGS. 9A and 9B are diagrams showing the ejection amount fluctuation in the arrangement direction of the printing elements in one chip 2. Here, in a state where the ink flow direction in the main flow path 14 is fixed from right to left, the alignment mark 23 is arranged to be positioned on the upper right (FIG. 9A) and arranged to be positioned on the lower left. Comparison is made in the case of (1) in FIG. In this embodiment, block driving is performed in order from the side opposite to the alignment mark 23, so in FIG. 9A, the driving order is from left to right, that is, in the direction opposite to the ink circulation direction. Then, the driving order is from right to left, that is, in the same direction as the ink circulation direction.

  In both FIGS. 9A and 9B, since the ink flows from the right side to the left side, the ink temperature also increases from the right to the left, and the discharge amount also gradually increases from the right side to the left side. Therefore, a discharge amount variation curve such as graph a is obtained. On the other hand, in the block drive, in the case of FIG. 9A, since the left block is driven in order toward the right block, the discharge amount increases from the left block to the right block, and the graph b Thus, a discharge amount fluctuation curve is obtained. In a state where the two conditions of the ink flow direction and the driving order are combined, a discharge amount fluctuation curve such as a graph a + b obtained by superimposing the graph a and the graph b is obtained. That is, fluctuations in the ejection amount due to these two conditions cancel each other, and as a result, a state in which fluctuations in the ejection amount with respect to the position of the recording element are suppressed is obtained as shown in graph a + b in each chip. .

  On the other hand, in the case of FIG. 9B, since the drive is sequentially performed from the right block to the left block, the discharge amount increases from the right block to the left block, and the discharge amount fluctuation as shown in the graph b2 This curve is obtained. In a state where the two conditions of the ink flow direction and the driving order are combined, a discharge amount fluctuation curve such as a graph a + 2b obtained by superimposing the graph a and the graph b2 is obtained. In other words, fluctuations in the ejection amount due to these two conditions increase each other, and as a result, in each chip, a state in which the fluctuations in the ejection quantity with respect to the position of the recording element are amplified is obtained as in graph a + b2. It is done.

  In view of the characteristics of density unevenness according to the direction of block driving and the direction of the main flow path, the present inventors have made a driving order and the direction of the main flow path in order not to make the density unevenness conspicuous in the entire image. As a result, the inventors have found that there is an effect in adjusting the orientations of a plurality of chips according to the situation. Hereinafter, two examples of the arrangement method of the plurality of chips 2 in the inkjet head H of the present embodiment will be described.

  FIGS. 10A and 10B are diagrams illustrating an arrangement state of the 18 chips Chip1 to Chip18 in the first embodiment and how the discharge amount varies in the x direction. The nine chips Chip1 to Chip9 shown on the left side are arranged so that the alignment mark 23 is located on the upper right, and discharge the ink supplied from the main flow path 14 that flows from the center toward the left. On the other hand, the nine chips Chip10 to Chip18 shown on the right side are arranged so that the alignment mark 23 is located at the lower left, and eject ink supplied from the main flow path 14 that flows from the center to the right. As a result, for any chip, the flow path direction and the block drive direction coincide with each other, and as shown in graph a + b of FIG. The change in the discharge amount cancels out.

  The solid line in FIG. 10B is a diagram showing the variation in the ejection amount over the entire inkjet head in a state where the variation in the ejection amount of each chip is aligned with the graph a + b. Although there is a gradual change throughout the entire area, there is no portion where the discharge amount changes greatly locally, so that no noticeable density unevenness is observed in the entire image.

  Here, as a comparative example, let us consider a case where all the chips are arranged in the same direction while maintaining the flow path direction of the main flow path. Specifically, FIG. 10A shows a case where the left nine chips Chip1 to Chip9 are aligned with the right nine chips Chip10 to Chip18. In this case, in the nine chips Chip1 to Chip9 on the left side, the direction of the flow path and the direction of block driving are opposite. As a result, as shown in the graph a + b2 of FIG. 9B, the change in the discharge amount accompanying the direction of the flow path and the change in the discharge amount accompanying the order of the block driving increase.

  The broken line in FIG. 10B shows the discharge amount fluctuation when the discharge amount fluctuation of Chip 1 to Chip 9 is represented by graph a + b2. It can be seen that the amount of fluctuation in the left half is larger than that in the right half, which changes slowly. When such an image is visually checked, the leftmost high density region stands out and may be recognized as density unevenness. On the other hand, if the present embodiment is employed in which the curve shown by the solid line in FIG. 10B is employed, the state of density fluctuation does not differ greatly between the left and right, and is gentle over the entire region. As a result, it is possible to obtain a high-quality image in which density unevenness is hardly visually recognized.

  In the first embodiment, the configuration in which the direction of the flow path and the direction of the block driving are matched in all chips has been described. However, the present invention is not limited to such a configuration. Even in a configuration in which the direction of the flow path and the direction of block driving are reversed, the effect of the present invention can be obtained by aligning such conditions for all chips.

  FIG. 11 is a diagram showing an arrangement state of 18 chips Chip1 to Chip18 and a discharge amount variation in each chip 20 in the present embodiment. The nine chips Chip1 to Chip9 shown on the left side are arranged so that the alignment mark 23 is located at the lower left, and eject the ink supplied from the main channel 14 flowing from the center toward the left. On the other hand, the nine chips Chip10 to Chip18 shown on the right side are arranged so that the alignment mark 23 is located on the upper right, and eject the ink supplied from the main flow path 14 flowing from the center to the right. As a result, for each chip, the flow path direction and the block drive direction are opposite directions, and as shown in the graphs, the change in the discharge amount with the flow path direction and the discharge amount with the block drive order It will be in a state where the change of each increase. Then, in the entire area of the ink jet head H, a discharge amount fluctuation is obtained such that the curve shown by the broken line in FIG.

  Even in such a case, it is avoided that the high density stands out only at one end portion, and the tendency of density fluctuation is unified over the entire region. As a result, it is possible to obtain an image in which density unevenness is hardly recognized visually.

  In the above description, the block driving order has been described as an example of the factor causing the directional ejection amount fluctuation in the chip. However, the factor is not limited to this. For example, even when the area of the discharge port changes gradually according to the position of the recording element, or when the distance from the heating resistor to the discharge port changes gradually, the change in the discharge amount is directional within the chip. Have Even when such factors further exist, if the combination of directivity of these multiple factors can be aligned for all the chips, the density fluctuation tendency is unified over the entire head area, and density unevenness is reduced. It is possible to obtain the effect of the present invention that the recognition is difficult.

  Furthermore, although the full-line type ink jet head as shown in FIG. 1 has been described as an example, the present invention is not limited to such a configuration. If a relatively long ink jet head is used by combining a plurality of chips, the effects of the present invention can be obtained even when mounted on a serial type recording apparatus.

1 Channel member
2 chips
14 Main channel
20 recording elements
H Inkjet head

Claims (10)

Recording elements that eject ink by applying energy are arranged in a predetermined direction, and when equal energy is applied, the ejection amount changes with a certain tendency according to the position of the recording element in the predetermined direction. A plurality of chips,
A plurality of flow paths for moving ink while sequentially supplying ink to the plurality of chips;
An inkjet head comprising:
The inkjet head according to claim 1, wherein a direction of ink movement in the flow path with respect to the predetermined direction is equal in the plurality of chips.   The plurality of blocks divided in the predetermined direction are sequentially driven in the predetermined direction, whereby the ejection amount of the recording element tends to increase in the direction in which the driving order advances. Item 10. The inkjet head according to Item 1.   The inkjet head according to claim 2, wherein the direction in which the order advances and the direction in which the ink moves are the same.   The inkjet head according to claim 2, wherein a direction in which the order advances and a direction in which the ink moves are different.   5. The plurality of flow paths are two flow paths that move ink in directions opposite to each other with respect to the predetermined direction while sequentially supplying ink to the same number of the chips. The inkjet head of any one of these.   The ink jet head according to claim 5, wherein the two flow paths move the ink so that a central portion in the predetermined direction of the ink jet head is an upstream end and both end portions are downstream ends.   The ejection amount of the recording element is constant according to the position in the predetermined direction because the area of the ejection port from which ink is ejected from the recording element differs depending on the position of the recording element in the predetermined direction. The inkjet head according to claim 1, wherein the inkjet head changes with a tendency.   The inkjet head according to claim 1, wherein the energy is generated by applying a voltage to the heating resistor.   Due to the fact that the distance from the heating resistor to the ejection port from which ink is ejected varies depending on the position of the recording element in the predetermined direction, the ejection amount of the recording element depends on the position in the predetermined direction. The inkjet head according to claim 8, wherein the inkjet head changes with a certain tendency.   10. The plurality of chips are arranged in the predetermined direction by a distance corresponding to a width in the predetermined direction of a sheet conveyed in a direction intersecting the predetermined direction. 2. An ink jet head according to item 1.

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