JP2007237534A - Liquid droplet ejection head and liquid droplet ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a correction such that a deterioration of an image in a boundary part of a liquid droplet ejection unit becomes inconspicuous. <P>SOLUTION: An error absorbing nozzle 222 is provided on the outside of each of nozzle areas 124A and 124B so that the boundary part between adjacent head units 114A and 114B can adjoin a joint part 220. A line-direction nozzle interval m between the error absorbing nozzles 222 is set shorter than a line-direction nozzle interval M between ordinary nozzles 122. When white streaks appear, an ink droplet is also ejected from the error absorbing nozzle 222, so as to eliminate the white streaks. Furthermore, the image, which is obtained by using the error absorbing nozzle 222, enables more gradation expressions than an image which is obtained by using the ordinary nozzle 122. This enables the correction to be performed to make the white streaks more inconspicuous. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge device.

  When a long ink jet recording head corresponding to the paper width is constructed by arranging a plurality of head units, the head units are arranged apart by a predetermined interval, for example, a nozzle interval. However, it is not easy to dispose the head units at exactly the same distance as the nozzles, and the spacing tends to vary. If the distance between the head units is too narrow, black streaks are generated, and if it is too wide, white streaks are generated. That is, image degradation is likely to occur at the joint portion of the head unit.

As a method of avoiding such image degradation such as white stripes and black stripes, the nozzles at the joint portions of the head unit are overlapped, and the overlap area is shared by the overlapped nozzles to form an image. Has been proposed. (For example, see Patent Document 1 and Patent Document 2).
JP-A-6-255098 JP 2001-1510 A

  However, in the configurations of Patent Document 1 and Patent Document 2, all nozzle intervals including the overlapped nozzles are the same interval (equal interval). For this reason, the correction with the overlapped nozzles is coarse and may stand out.

  The present invention has been made to solve the above-described problems, and an object thereof is to more inconspicuously correct image deterioration at a joint portion of a droplet discharge unit.

  In order to achieve the above object, a droplet discharge head according to claim 1, wherein a plurality of droplet discharge units for discharging droplets from nozzles arranged at a predetermined interval are arranged. In this case, error absorbing nozzles are provided outside the nozzle region where the nozzles of the droplet discharge unit are arranged at an interval narrower than the predetermined interval.

  The droplet discharge head according to the first aspect is configured by arranging a plurality of droplet discharge units that discharge droplets from nozzles arranged at a predetermined interval. Further, error absorbing nozzles are provided outside the nozzle area where the nozzles are arranged at intervals smaller than a predetermined interval.

  Now, it is necessary to accurately arrange the adjacent droplet discharge units so that the nozzles at the joint portions (boundary portions) are connected at a predetermined interval. However, if the nozzles are not accurately arranged due to an error or the like, the nozzle interval becomes discontinuous and image degradation occurs.

  For such image degradation, it is possible to correct the image degradation to a high resolution by using an error absorbing nozzle provided outside the nozzle region where the nozzles of the droplet discharge unit are arranged at a smaller interval than the predetermined interval. Can do.

  For example, when white streaks occur because the nozzle spacing is too wide at the joint between adjacent liquid droplet ejection units, correction is performed so that the liquid droplets are also ejected from the error absorbing nozzle and the white lines are filled. On the other hand, when black streaks occur because the nozzle spacing is too narrow, droplets are ejected from the error absorbing nozzles instead of the nozzles outside the adjacent droplet ejection unit, and the black streaks are corrected.

  In this way, by correcting the image degradation that occurs in the joint portion of the adjacent liquid droplet ejection units (boundary portion of the nozzle region) using an error absorbing nozzle having an interval smaller than a predetermined interval, that is, high resolution. By correcting with, correction is made so that image degradation (white stripes or black stripes) is not noticeable.

  The droplet discharge head according to claim 2, wherein the nozzles of the droplet discharge unit are arranged in a matrix in a lattice shape with a direction perpendicular to a row direction and an angle as a column direction. Yes.

  In the droplet discharge head according to the second aspect, the nozzles of the droplet discharge unit are arranged in a matrix in a lattice shape with a direction having an angle with a direction orthogonal to the row direction as a column direction. For this reason, the nozzles are arranged with high density when viewed in the direction orthogonal to the row direction. Therefore, it is possible to discharge droplets in a wide area with high resolution without increasing the nozzle spacing itself.

  The droplet discharge head according to claim 3, wherein a boundary of the nozzle region with the adjacent droplet discharge unit has an angle with the row direction, and the nozzle is viewed in a direction orthogonal to the row direction. At least a part of the region overlaps the nozzle region of the adjacent droplet discharge unit.

  In the droplet discharge head according to claim 3, the boundary of the nozzle region between adjacent droplet discharge units has an angle with the row direction, and at least a part of the nozzle region when viewed in a direction orthogonal to the row direction. Overlaps the nozzle area of the adjacent droplet discharge unit.

  In such a configuration, if the droplet discharge unit is not accurately arranged due to an error or the like, the nozzle interval is discontinuous over the entire region where the adjacent droplet discharge unit and the nozzle region overlap, and image degradation occurs in a wide region. Occurs. Further, such a configuration can correct the image deterioration of the joint portion by shifting the droplet discharge unit and overlapping the normal nozzles and forming an image by sharing both of the overlapping portions of the nozzles. Can not.

  However, by providing error absorbing nozzles outside the nozzle region at intervals smaller than a predetermined interval, it is possible to correct image degradation at the joint portion with high resolution.

  The droplet discharge head according to claim 4, wherein an outer shape of the nozzle region of the droplet discharge head is a parallelogram shape, a trapezoidal shape, a triangular shape, or a combination thereof. It is a feature.

  In the droplet discharge head according to the fourth aspect, the outer shape of the nozzle region of the droplet discharge head is a parallelogram shape, a trapezoidal shape, a triangular shape, or a combination thereof.

  In such a configuration, the nozzle interval is discontinuous over the entire region where the adjacent droplet discharge unit and the nozzle region overlap, and image degradation occurs in a wide region. In addition, it is also impossible to correct image deterioration in the joint portion by shifting the droplet discharge unit and overlapping the normal nozzles and forming an image by sharing both of the overlapping nozzles.

  However, by providing the error absorbing nozzles outside the nozzle region at intervals smaller than a predetermined interval, it is possible to correct image degradation at the joint portion with high resolution.

  The droplet discharge device according to claim 5 forms an image on a transported recording medium, and the droplet discharge head adjacent to any one of claims 1 to 4. Control means for controlling ejection of liquid droplets from the nozzle adjacent to the joint portion and the error absorbing nozzle so as to correct image degradation at the joint portion.

  According to a fifth aspect of the present invention, an image is formed on the transported recording medium by the liquid droplet ejection head according to any one of the first to fourth aspects. Further, the control unit controls the discharge of the liquid droplets from the nozzle adjacent to the joint portion and the error absorbing nozzle so as to correct the image deterioration of the joint portion between the adjacent liquid droplet ejection heads. Therefore, it is possible to correct image degradation with high resolution.

  The liquid droplet ejection apparatus according to claim 6 is characterized in that the control means corrects image deterioration of the joint portion by using halftone processing.

  In the droplet discharge device according to the sixth aspect, since the control means corrects the image deterioration of the joint portion using the halftone process, the correction is made more conspicuously.

  The liquid droplet ejection apparatus according to claim 7, further comprising a detection unit that detects image deterioration at a joint portion between the adjacent liquid droplet ejection heads, and the control unit is configured based on a detection result of the detection unit. It is characterized by correcting image deterioration at the joint portion.

  In the droplet discharge device according to claim 7, the detection unit detects image deterioration of a joint portion between adjacent droplet discharge heads, and the control unit automatically detects the joint portion based on the detection result of the detection unit. Correct image degradation.

  9. The liquid droplet ejection apparatus according to claim 8, wherein the liquid droplet ejection area of the liquid droplet ejection head is equal to or larger than a recording area width of the recording medium, and the recording is carried in a state where the liquid droplet ejection head is fixed. An image is formed by discharging droplets onto a medium.

  In the droplet discharge device according to the eighth aspect, the droplet discharge region of the droplet discharge head is equal to or larger than the recording region width of the recording medium. An image is formed over a wide range in a short time by ejecting droplets onto a recording medium conveyed with the droplet ejection head fixed, thereby forming an image. Furthermore, by providing the error absorbing nozzle, the image deterioration at the joint portion of the droplet discharge unit is corrected to high resolution and is not noticeable.

  As described above, according to the present invention, by providing the error absorbing nozzles arranged at intervals smaller than the predetermined interval outside the nozzle region of the nozzles arranged at predetermined intervals, the connection of the droplet discharge units is achieved. There is an effect that the image degradation of the eye part can be corrected to a high resolution so as to be inconspicuous.

  FIG. 1 shows an ink jet recording apparatus 12 of the present embodiment. The ink jet recording apparatus 12 includes a control unit 8 that includes a CPU, a ROM, a RAM, and the like. The control unit 8 controls various controls of the entire apparatus. In addition, an operation panel 11 for displaying various information to the user and performing various operations is provided on the upper part of the front of the apparatus.

  A paper feed tray 16 is provided at the lower part of the ink jet recording apparatus 12, and the recording paper P stacked in the paper feed tray 16 can be taken out one by one by a pickup roll 18. The taken recording paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22.

  Above the paper feed tray 16, an endless transport belt 28 stretched around a drive roll 24 and a driven roll 26 is disposed. A recording head array 30 is disposed above the conveyor belt 28 and faces the flat portion 28F of the conveyor belt 28. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The recording paper P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information adhere from the recording head array 30 in a state of facing the recording head array 30. Is done.

  In the present embodiment, the recording head array 30 has a long shape in which the effective recording area is equal to or larger than the width of the recording paper P (the length in the direction orthogonal to the transport direction), and yellow (Y), magenta (M ), Four ink jet recording heads 32 corresponding to four colors of Sian (S) and black (K) are arranged along the transport direction, and a full color image can be recorded. (See also FIG. 4).

  Each inkjet recording head 32 is controlled by the control unit 8. For example, the control unit 8 determines the ejection timing of the ink droplets and the nozzle 122 (see FIGS. 5 and 6) to be used according to the image information, and sends a drive signal to the inkjet recording head 32.

  The recording head array 30 is not moved in a direction orthogonal to the conveyance direction A (see FIG. 4) of the recording paper P (one-pass printing method). However, if it is configured to move as necessary in the direction orthogonal to the transport direction A, an image with higher resolution can be recorded by multi-pass image recording, or a defect in the inkjet recording head 32 can be recorded. It is also possible to prevent it from being reflected in.

  Four maintenance units 34 corresponding to the respective ink jet recording heads 32 are arranged on both sides of the recording head array 30. When maintenance is performed on the inkjet recording head 32, the recording head array 30 moves upward as shown in FIG. 2, and the maintenance unit 34 moves to a gap formed between the conveyance belt 28 and the maintenance unit 34. Get in. Then, a predetermined maintenance operation (vacuum, dummy jet, wiping, capping, etc.) is performed while facing the nozzle surface 32N (see FIG. 3).

  As shown in FIG. 3, a charging roll 36 to which a power source 38 is connected is disposed on the upstream side of the recording head array 30. The charging roll 36 is driven while sandwiching the conveyance belt 28 and the recording paper P with the driven roll 26, and is between a pressing position for pressing the recording paper P against the conveyance belt 28 and a separation position separated from the conveyance belt 28. Can be moved. In the pressing position, a predetermined potential difference is generated between the grounded driven roll 26 and the recording paper P can be charged and electrostatically attracted to the transport belt 28.

  A peeling plate 40 is disposed on the downstream side of the recording head array 30, and the recording paper P is peeled from the conveyance belt 28. The peeled recording paper P is conveyed by a plurality of discharge roller pairs 42 constituting a discharge path 44 on the downstream side of the peeling plate 40 and discharged to a paper discharge tray 46.

  As shown in FIG. 1 and FIG. 2, above the recording head array 30, four colors of yellow (Y), magenta (M), cyan (S), and black (K) corresponding to each inkjet recording head 32 are provided. An ink tank 54 is provided. An ink flow path 200 connects each ink tank 54 and each ink jet recording head 32. Each color ink stored in each ink tank 54 passes through the ink flow path 200, is filtered by a filter device (not shown), and is supplied to each inkjet recording head 32.

  A reading sensor 7 is disposed on the upstream side of the maintenance unit 34. Then, a predetermined test pattern is printed on the recording paper P, and the predetermined test pattern is read by the reading sensor 7 and analyzed and evaluated by the control unit 8 to detect image deterioration.

  Next, the ink jet recording head 32 will be described.

  As shown in FIG. 4, the ink jet recording head 32 includes a head bar 112 set to a length corresponding to the maximum width of the recording paper P. The head bar 112 is fixedly supported by a support body (not shown) at a position facing the conveyance path of the recording paper P in the ink jet recording apparatus 12. In the head bar 112, a plurality of head units 114 are connected to the support member 113 in a row in the row direction B, which is a direction orthogonal to the conveyance direction A of the recording paper P. Each head unit 114 is fastened to the support member 113 with screws (not shown), and can be individually replaced. The recording paper P is transported in the transport direction A and printed by each head unit 114 disposed on the support member 113. That is, when the recording paper P passes once below the head bar 112, the entire width of the recording paper P (the direction perpendicular to the transport direction A (row direction) without scanning the ink jet recording head 32 (recording head array 30)). The width B) can be printed.

  As shown in FIGS. 4 and 5, the head unit 114 has a substantially parallelogram shape, and two element substrates 116 and 118 are disposed on the upper surface of the head unit 114. The two element substrates 116 and 118 have a substantially trapezoidal shape, and are arranged in the head unit 114 so that the oblique sides (short oblique sides) having the same length of the substantially trapezoidal shape face each other. The element substrates 116 and 118 are configured such that the inner angle formed by the short hypotenuse is larger than the outer angle formed by the long hypotenuse. The head unit 114 has extended portions 120A and 120B in which two obtuse angle portions of a substantially parallelogram project outward, so that the gap between the edge of the head unit 114 and the element substrates 116 and 118 is not narrowed. A predetermined width is secured. Further, the head unit 114 includes angled portions 121A and 121B in which two acute angle portions of a substantially parallelogram are cut. As shown in FIG. 4, when a plurality of head units 114 are connected in a row, adjacent extending portions 120A and 120B and cornered portions 121A and 121B are configured to face each other.

  As shown in FIG. 5, nozzle regions 124 </ b> A and 124 </ b> B in which a plurality of nozzles 122 are disposed are formed on the opposite side of the element substrates 116 and 118 (see FIG. 4) of the head unit 114. That is, the element substrates 116 and 118 are provided at positions corresponding to the two nozzle regions 124A and 124B, and ink droplets are ejected from the nozzles 122 into the substantially trapezoidal regions of the element substrates 116 and 118. A piezoelectric element group (not shown) is formed. (To be precise, the element substrates 116 and 118 include an area of an error absorbing nozzle 222 described later).

  The nozzle regions 124A and 124B have the same shape as the element substrates 116 and 118, are trapezoidal, and are arranged so as to overlap when rotated 180 °.

  As shown in FIG. 6, the nozzle plate 130 is formed with nozzles 122 that eject ink droplets. A communication hole 154 that communicates with the nozzle 122 is formed in the communication hole plate 132, and a communication hole 156 is formed in the damper member 134. The pool plates 136, 138, and 140 are formed with communication holes 158, 160, and 162, respectively, and the communication hole plate 142 is formed with a communication hole 164. Further, a communication hole 166 is formed in the flow path plate 144, and a communication hole 168 is formed in the communication hole plate 142. These nozzles 122, communication holes 154, 156, 158, 160, 162, 164, 166, 168 communicate with each other and are connected to a pressure chamber 170 formed in the pressure chamber plate 148.

  On the other hand, in the communication hole plate 132, a hollow portion 172 is formed below the damper member 134. The pool plates 136, 138, and 140 are formed with ink pools 174, 176, and 178, respectively, and store ink supplied from ink supply holes (not shown). The ink pools 174, 176, 178, the supply hole 180, the ink flow path 182, the supply hole 184, and the pressure chamber 170 communicate with each other, and ink enters the pressure chamber 170 from the ink pools 174, 176, 178. Is supplied.

  Further, a piezoelectric element 186 is attached to the upper part of the vibration plate 150 so that a driving voltage is applied from the flexible wiring board. These piezoelectric elements 186 are respectively provided above the pressure chambers 170 communicating with the individual nozzles 122, and a piezoelectric element group constituted by a large number of piezoelectric elements 86 is connected to the element substrates 116 and 118 shown in FIG. It has become.

  Now, as shown in FIG. 5, the nozzles 122 are arranged in a matrix in a lattice shape in plan view. The nozzles 122 arranged in a matrix in a grid form are such that the row direction B is perpendicular to the conveyance direction A of the recording paper P, and the column direction C has an angle θ with the conveyance direction A of the recording paper P.

  Further, as shown in FIG. 5B, the nozzles 122 are connected from the nozzle 122 at the end of the nozzle region 124B to the nozzle 122 at the end of the nozzle region 124A so that the intervals of the nozzles 122 are the same. Therefore, when the nozzles 122 are projected in the conveyance direction A of the recording paper P, the nozzles 122 are equally spaced.

  Further, as shown in FIG. 7, the joint portion 220 (boundary portion) between the head units 114 is similarly spaced from the nozzle 122 at the end of the nozzle region 124B to the nozzle 122 at the end of the nozzle region 124A. Are connected at the same interval. Therefore, when the nozzles 122 are projected in the conveyance direction A of the recording paper P, the nozzles 122 are equally spaced.

  Then, when the recording paper P passes under the ink jet recording head 32, a high resolution image is formed by ejecting ink droplets from the nozzles 122 in order.

  As shown in FIG. 7, an error absorbing nozzle 222 is provided outside the nozzle regions 124A and 124B so as to be adjacent to the joint portion 220 at the boundary between the adjacent head units 114A and 114B. It should be noted that the nozzle interval m in the row direction B of the error absorbing nozzle 222 is narrower than the nozzle interval M in the row direction B of the normal nozzle 122. (In this embodiment, M = 2 m).

  The error absorbing nozzle 222 has the same shape as that of the normal nozzle 122 shown in FIG. 6, and the piezoelectric elements 186 and the pressure chambers 170 corresponding to the error absorbing nozzles 222 are provided so that ink droplets can be ejected in the same manner. Have. (The nozzle 122 of FIG. 6 is replaced with the error absorbing nozzle 222, and the same configuration is used thereafter). Similarly, the ejection of ink droplets is controlled by the control unit 8.

  Next, the operation of this embodiment will be described.

  As shown in FIG. 4, the head units 114 are arranged in a line in the row direction B. In such a configuration, when an error occurs in the arrangement of the head unit 114, image degradation occurs in the joint portion 220 (see also FIG. 7). In particular, when the head unit 114 can be replaced as in the present embodiment, the mounting position accuracy of the head unit 114 cannot be sufficiently high, so that image degradation is likely to occur in the joint portion 220.

  Now, as shown in FIG. 8, it is assumed that the distance in the row direction B between the head unit 114A and the head unit 114B is separated from the defined distance by an error L. Then, as shown in the figure, the gap between the nozzles 122 of the other head unit 114B connected from the nozzles 122 of the one head unit 114A is opened across the joint portion 220, and a white stripe T is generated. The white stripe T is generated in the entire area of the joint portion 220. (A whole area is generated in the nozzle region overlapping in the direction orthogonal to the row direction B). A dot G in the figure represents an image (dot) formed on the recording paper P by ink droplets ejected from the nozzle 122. 9 to 12 described later, similarly, the dot G represents a dot formed on the recording paper P by ink droplets ejected from the nozzle 122.

  As described above, the inkjet recording apparatus 12 prints a predetermined test pattern on the recording paper P, the reading sensor 7 reads the predetermined test pattern, and the control unit 8 analyzes and evaluates the image deterioration, that is, , White streak T can be detected.

  When the white stripe T is detected, the control unit 8 ejects ink droplets also from the error absorbing nozzle 222 to fill the white stripe T as shown in FIG. A dot g in the figure represents an image (dot) formed by the ink droplets ejected from the error absorbing nozzle 222. 10 and 12 to be described later, similarly, the dot g represents a dot formed on the recording paper P by the ink droplets ejected by the error absorbing nozzle 222.

  Now, as shown in FIG. 10, in order to fill the white stripe T, the dots g formed by the error absorbing nozzle 222 are arranged by performing a halftone process. Specifically, the image density is area-modulated using four error absorbing nozzles 222 (the error absorbing nozzles 222 of both the head unit 114A and the head unit 114B), and a pseudo halftone image, so-called half-tone image is obtained. It is a tone image. Therefore, the correction by filling the white stripe T with the dot g is not conspicuous.

  As shown in FIGS. 7 and 9, the error absorbing nozzle 22 has an interval m that is narrower than the interval M in the row direction of the normal nozzle 122. (In this embodiment, M = 2 m). That is, the error absorbing nozzle 222 can form an image with higher resolution than the normal nozzle 122. For this reason, an image using the error absorbing nozzle 222 can express more gradations than the normal nozzle 122. Therefore, the white stripe T can be corrected more inconspicuously.

  In the above description, the four error absorbing nozzles 222 are used. However, the present invention is not limited to this. Three or less error absorbing nozzles 222 may be used. In short, the error absorbing nozzle 222 may be used for correction so that the image degradation of the joint portion 220 is least noticeable depending on the width of the white stripe T, the surrounding image continuous with the white stripe T, and the like.

  Now, as shown in FIG. 11, it is assumed that the distance in the row direction B between the head unit 114A and the head unit 114B is narrower in the row direction B by an error L than the prescribed interval. Then, as shown in the figure, the gap between the nozzles 122 of the other head unit 114B connected to the nozzles 122 of one head unit 114A is narrowed across the joint portion 220, and black stripes K are generated. Similar to the white stripe T, the black stripe K is generated over the entire joint portion 220.

  Similarly, the ink jet recording apparatus 12 prints a predetermined test pattern on the recording paper P, the reading sensor 7 reads the predetermined test pattern, and the control unit 8 analyzes and evaluates the image deterioration, that is, black streak K. Can be detected.

  When the black streak K is detected, the control unit 8 stops the ejection of ink droplets from the nozzle 122A of the head unit 114A adjacent to the joint portion 220 as shown in FIG. 12, and from the error absorbing nozzle 222A of the head unit 114B. Ink enemies are ejected to correct black streaks K.

  In the above description, the black streak K is corrected by using one error absorbing nozzle 222 and not discharging one normal nozzle 122 for one black streak K. However, the present invention is not limited to this. A plurality of error absorbing nozzles 222 may be used, and there may be a plurality of normal nozzles 122 that are not ejected. In short, correction may be performed using the error absorbing nozzle 222 so that the image degradation of the joint portion 220 is least noticeable depending on the width of the black stripe K, the surrounding image continuous with the black stripe K, and the like.

  A flowchart shown in FIG. 13 summarizes such control. Next, this flowchart will be described.

  First, in step 300, this control is started at a predetermined timing. The predetermined timing includes when the power is turned on, after printing a predetermined number of sheets, and immediately after the head unit 114 is replaced. The user may operate the operation panel 11 (see FIG. 1).

  In step 302, a predetermined test pattern is printed on the recording paper P.

  In step 304, the test chart is read by the reading sensor 7 (see FIG. 1), and the control unit 8 evaluates image deterioration (white stripe T or black stripe K).

  In step 306, based on the read result, the control unit 8 (see FIG. 1) determines and feeds back the error absorbing nozzle 222 that ejects ink droplets and the normal nozzle 122 that is not ejected so as to correct image degradation. . If no image deterioration is observed, the error absorbing nozzle 222 is not used.

  In step 308, the control ends.

  Note that step 304 may be evaluated by the user visually or with a measuring instrument. Step 306 may also be fed back by the user operating the operation panel 11 or adjusting the head unit 114 using a tool such as a screwdriver.

  In this way, the image of the joint portion 220 is corrected by forming an image of the joint portion 220 between the adjacent head units 114 using the normal nozzle 122 and the error absorbing nozzle 222. Furthermore, since the error absorbing nozzle 222 can form an image with a higher resolution than the normal nozzle 122, the image deterioration of the joint portion 220 can be corrected so as not to be noticeable.

  In particular, as in this embodiment, the boundary between the nozzle regions 124A and 126B between the adjacent head units 114 has an angle with the row direction B, and when viewed in the direction orthogonal to the row direction B, the nozzle regions 124A and 124B. Is overlapped with the nozzle regions 124A and 124B of the adjacent head unit 114 (see FIG. 7), the error (variation) in the arrangement of the head unit 114 is applied to all the nozzles 122 adjacent to the joint portion 220. As a result, image deterioration (black stripes / white stripes) is caused over the entire joint portion 220, and the influence is great.

  In the case of a one-pass printing method in which printing is performed with a long ink jet recording head fixed, it is also difficult to correct image deterioration.

  Furthermore, if the joint portion (boundary portion) of the head unit is in the same direction as the row direction as in the configuration of Japanese Patent Laid-Open No. 6-255098 and the configuration of Japanese Patent Laid-Open No. 2001-1510, the head unit is shifted. Although normal nozzles can be overlapped, as in this embodiment, when the joint portion of the head unit (the boundary portion of the nozzle region) has an angle with the row direction, the head unit 114 is The normal nozzle 122 cannot be overlapped by shifting.

  However, as described above, by providing the droplet discharge nozzle 222 outside the nozzle regions 124A and 124B, the image deterioration of the joint portion 220 can be corrected with high resolution. It is particularly effective to apply the invention.

  In addition, this invention is not limited to the said embodiment.

  For example, in the above embodiment, the two droplet discharge nozzles 222 are provided outside the nozzle regions 124A and 124B, but the present invention is not limited to this. One may be sufficient, and three or more may be sufficient.

  Further, for example, in the above embodiment, the nozzle regions 124A and 124B have a trapezoidal shape, but may have other shapes. For example, as shown in FIG. 14, it may be a nozzle region 324 having a parallelogram shape, or it may be a nozzle region 424 having a triangular shape as shown in FIG. Alternatively, as shown in FIG. 16, the shape may be a combination of a triangular nozzle region 424 and a trapezoidal nozzle region 426.

  Further, as in the configuration of Japanese Patent Application Laid-Open No. 6-255098 and the configuration of Japanese Patent Application Laid-Open No. 2001-1510, the joint portion of the head unit (boundary portion of the nozzle region) may be in the same direction as the row direction.

  In the above-described embodiment, a long ink jet recording head having a width substantially equal to the width of the recording paper is provided, and the ink jet recording head is fixed and performs recording while transporting only the recording medium, so-called FWA (Full) Although it is an inkjet recording apparatus of a (Width Array) type, it is not limited to this. The ink jet recording head can also be applied to a so-called PWA (Partial Width Array) ink jet recording apparatus that performs printing while reciprocating in a direction orthogonal to the conveyance direction of the recording paper P.

  The present invention is not limited to recording characters and images on the recording paper P. That is, the recording medium is not limited to the recording paper P, and the liquid to be discharged is not limited to ink. For example, ink droplets are ejected onto a polymer film or glass to create a color filter for display, or welded solder is ejected onto a substrate to form component mounting bumps. In addition, the present invention can be applied to all droplet discharge apparatuses.

  Further, it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

It is the schematic which shows the inkjet recording device of this invention in an image recording state. It is the schematic which shows the inkjet recording device of this invention in a maintenance state. FIG. 2 is a schematic diagram illustrating a conveyance belt and the vicinity thereof in the inkjet recording apparatus of the present invention. It is a perspective view which shows an inkjet recording head typically. (A) is a top view which shows the nozzle area | region of the head unit which comprises an inkjet recording head, (B) is a figure which shows typically the boundary part of the nozzle area | region of (A). It is a fragmentary sectional view showing a head unit. It is a figure which shows typically the joint part with an adjacent head unit. It is explanatory drawing explaining the white stripe which generate | occur | produced in the joint part. It is explanatory drawing explaining correction | amendment of the white stripe which generate | occur | produced in the joint part. It is an enlarged view of the state which correct | amended the white stripe which generate | occur | produced in the joint part. It is explanatory drawing explaining the black stripe which generate | occur | produced in the joint part. It is explanatory drawing explaining correction | amendment of the black stripe which generate | occur | produced in the joint part. It is a flowchart of control which corrects image degradation. It is a figure which shows typically the example of the nozzle region of a parallelogram shape. It is a figure which shows typically the example of a triangular nozzle area. It is a figure which shows typically the example which combined the triangular nozzle area | region and the trapezoidal nozzle area | region.

7 Reading sensor (detection means)
8 Control unit (control means)
12 Inkjet recording device (droplet ejection device)
32 Inkjet recording head (droplet ejection head)
114 Head unit (droplet discharge unit)
122 nozzle 124A nozzle area 124B nozzle area 220 joint part 222 error absorbing nozzle

Claims (8)

A droplet discharge head configured by arranging a plurality of droplet discharge units that discharge droplets from nozzles arranged at predetermined intervals,
A droplet discharge head, wherein an error absorbing nozzle is provided at an interval smaller than the predetermined interval outside a nozzle region where the nozzle of the droplet discharge unit is disposed.   2. The droplet discharge head according to claim 1, wherein the nozzles of the droplet discharge unit are arranged in a matrix in a grid pattern with a direction perpendicular to a row direction and an angle as a column direction. The boundary of the nozzle region with the adjacent droplet discharge unit has an angle with the row direction,
3. The droplet discharge head according to claim 2, wherein when viewed in a direction perpendicular to the row direction, at least a part of the nozzle region overlaps with a nozzle region of the adjacent droplet discharge unit.   4. The droplet discharge according to claim 3, wherein an outer shape of the nozzle region of the droplet discharge head is a parallelogram shape, a trapezoidal shape, a triangular shape, or a combination thereof. head. The droplet discharge head according to any one of claims 1 to 4, wherein an image is formed on a transported recording medium;
Control means for controlling ejection of droplets from the nozzle adjacent to the joint portion and the error absorbing nozzle so as to correct image degradation of the joint portion between the adjacent droplet ejection heads;
A droplet discharge apparatus comprising:   The liquid droplet ejection apparatus according to claim 5, wherein the control unit corrects image deterioration of the joint portion by using halftone processing. Comprising a detecting means for detecting image deterioration at a joint portion between the adjacent droplet discharge heads,
The liquid droplet ejection apparatus according to claim 5, wherein the control unit corrects image deterioration of the joint portion based on a detection result of the detection unit. The droplet discharge area of the droplet discharge head is greater than or equal to the recording area width of the recording medium,
8. The liquid according to claim 5, wherein an image is formed by ejecting droplets onto the transported recording medium medium in a state where the droplet ejection head is fixed. 9. Drop ejection device.

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