JP5699354B2 - Inkjet recording apparatus and head unit - Google Patents

Description

  The present invention relates to an ink jet recording apparatus and a head unit, and more particularly to an ink jet recording apparatus having a plurality of head units for recording an image by discharging ink, and the head unit.

  The ink jet recording apparatus records an image by discharging ink onto a sheet from a minute discharge port. In such an ink jet recording apparatus, a serial type that records an image on a sheet by ejecting ink while moving a recording head having an ejection port, and records an image by ejecting ink on a sheet conveyed without moving. There is a line type to do. Since the line type is easier to speed up than the serial type, it is expected to be used for large printing systems and bookbinding systems that record images on a large amount of paper at once.

  Even when such a line type recording head is employed, various errors such as a manufacturing error of the recording head, a manufacturing error of the ink jet recording apparatus, and an installation error of the recording head to the apparatus may occur. In an ink jet recording apparatus that records a plurality of color images by superimposing a plurality of colors, there is a possibility that a shift occurs in each color image due to such an error. For this reason, there has been proposed an image recording apparatus that creates correction data for correcting the characteristics of the recording head at two-dimensional positions of a plurality of recording heads and adjusts an input signal to the recording head based on the correction data. (For example, refer to Patent Document 1).

JP 2003-291325 A

  The recording head needs to be replaced when a different color ink is used or when a problem such as ink clogging occurs. However, due to individual errors of each of the recording heads, an image shift that has not occurred until then may occur due to the replacement of the recording head. In recent years, there has been an increasing demand for image quality for inkjet recording apparatuses, and image misalignment due to such errors cannot be ignored.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to suppress image shift in an ink jet recording apparatus having a plurality of head units that eject ink and record an image. .

  In order to solve the above problems, an ink jet recording apparatus according to an aspect of the present invention includes a plurality of detachable head units that record an image by ejecting ink while being held at a predetermined position with respect to a sheet being conveyed. A data acquisition unit that acquires unit-side correction data indicating the ink discharge position from each of the plurality of head units, and by adjusting the ink discharge timing of each of the plurality of head units using the acquired unit-side correction data, An image shift correction unit that corrects a shift of an image recorded by the head unit.

  According to this aspect, it is possible to correct the image shift using individual errors such as manufacturing errors of each of the plurality of head units. For this reason, for example, even when a plurality of head units are replaced, image shift due to individual errors of the head units can be suppressed.

  You may further provide the memory | storage part holding the main body side correction data which show the relative position of each of a some head unit. The image misalignment correction unit may correct misalignment of images recorded by the plurality of head units by using both the acquired unit side correction data and the main body side correction data held.

  According to this aspect, it is possible to control image recording by the head unit in consideration of both individual errors of the head unit and errors of the main body of the inkjet recording apparatus. For this reason, compared with the case where only unit side correction data is used, image shift can be suppressed more.

  Each of the plurality of head units may have a plurality of recording heads each recording an image by discharging ink. Each of the plurality of recording heads is arranged so as to record non-identical images in the width direction perpendicular to the paper transport direction, and the data acquisition unit is a unit side indicating each ink ejection position of the plurality of recording heads. Correction data may be acquired.

  For example, an ink jet recording apparatus using a line head which is a recording head in which nozzles for ejecting ink are arranged in a line is known. Here, there are cases where an ink jet recording apparatus capable of recording an image over the entire length of the image recording width by arranging line heads shorter than the entire length of the image recording width so as to record images of non-identical portions. When a single head unit has a plurality of recording heads as described above, recording is performed even within a single head unit due to individual errors of each of the plurality of recording heads or mounting errors of the recording heads to the head unit. Different errors may occur from head to head. According to this aspect, it is possible to suppress image shift caused by such an error.

  At this time, the data acquisition unit, when the paper transport direction is the Y direction and the width direction is the X direction, Y direction position data indicating the Y ink discharge position of each of the plurality of recording heads, and the plurality of recording heads Unit-side correction data including X-direction position data indicating the entire ink protruding position in the X direction may be acquired.

  Another aspect of the present invention is a head unit. The head unit is detachably provided in the ink jet recording apparatus, and when attached to the ink jet recording apparatus, the head unit records an image by ejecting ink while being held at a predetermined position with respect to the conveyed paper. The provided head unit includes a storage unit that holds unit-side correction data indicating the ink ejection position, and a data output unit that outputs the unit-side correction data to the mounted ink jet recording apparatus.

  According to this aspect, when the head unit is mounted on the main body of the ink jet recording apparatus, it is possible to perform image shift correction using the unit side correction data on the main body side. For this reason, it is possible to suppress an image shift due to an error of the head unit.

  ADVANTAGE OF THE INVENTION According to this invention, the image shift | offset | difference in the inkjet recording device which has the some head unit which discharges ink and records an image can be suppressed.

1 is a front view schematically showing an ink jet recording apparatus according to a first embodiment. It is a front view of a head unit. It is a right view of a head unit. FIG. 4 is a diagram of the head unit viewed from a viewpoint P in FIG. 3. It is a front view of a head unit when a 1st raising / lowering unit exists in a 2nd position. It is a right view of a head unit when a 1st raising / lowering unit exists in a 2nd position. It is a front view of a head unit when a 1st raising / lowering unit exists in a 3rd position. It is a right view of a head unit when a 1st raising / lowering unit exists in a 3rd position. 1 is a functional block diagram of an ink jet recording apparatus according to a first embodiment. It is a figure which shows the data structure of unit data. It is a figure for demonstrating the content of unit side correction data. It is a figure for demonstrating the content of the main body side correction data. (A) is a perspective view of the periphery of the first lifting unit when the first lifting unit is in the first position in the ink jet recording apparatus according to the second embodiment. FIG. 6B is a top view of the periphery of the first lifting unit when the first lifting unit is at the first position in the inkjet recording apparatus according to the second embodiment. (A) is a perspective view of the periphery of the first elevating unit when the first elevating unit is in the third position in the ink jet recording apparatus according to the second embodiment. (B) is a top view of the periphery of the first elevating unit when the first elevating unit is in the third position in the ink jet recording apparatus according to the second embodiment.

  Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a front view schematically showing the ink jet recording apparatus 10 according to the first embodiment. The ink jet recording apparatus 10 includes a paper feeding device 12, an image recording device 14, and a stacker 16.

  The sheet feeding device 12 includes a sheet feeding table 20 and a sheet feeding mechanism 22. The paper feed table 20 can be raised and lowered, and the paper feed table 20 is lifted to a position where the uppermost paper among the stacked papers can be fed by the paper feed mechanism 22. The paper feed mechanism 22 sends out the uppermost paper that is stacked on the paper feed table 20.

  The sheet feeding device 12 includes a sheet feeding conveyance path 24, a portion on the upstream side in the sheet conveyance direction (hereinafter referred to as “upstream side”) of the main conveyance path 28, and a sheet conveyance direction downstream side (hereinafter referred to as “hereinafter referred to as“ upstream side ”). "Downstream side") is provided. The paper fed out by the paper feed mechanism 22 passes through the paper feed conveyance path 24 and is carried into the main conveyance path 28. A rejection unit 30 is provided in the middle of the main conveyance path 28 so as to branch from the main conveyance path 28. For example, when an error such as double feeding is detected in the paper feed mechanism 22, the paper in which the error is detected is discharged to the reject unit 30. Since such an error detection method and the configuration of the reject unit 30 are known, the description thereof is omitted.

  The image recording device 14 is provided with a downstream portion of the main conveyance path 28. The image recording apparatus 14 is provided with a belt transport mechanism 40 that transports the paper transported through the main transport path 28. The belt conveyance mechanism 40 conveys the sheet while adsorbing the sheet onto the conveyance surface 40a by the suction force of the charged belt. Since the structure of the belt conveyance mechanism 40 is well-known, description is abbreviate | omitted. A plurality (two in the first embodiment) of head units 42 are provided above the belt conveyance mechanism 40.

  The image recording apparatus 14 includes upstream portions of the discharge path 44, the branch conveyance path 46, and the reverse conveyance path 26. The discharge path 44 and the branch conveyance path 46 are provided to branch from the downstream side of the belt conveyance mechanism 40, and the sheet conveyed from the belt conveyance mechanism 40 is sent to the branch conveyance path 46 or the discharge path 44. A paper reversing mechanism 48 is provided on the downstream side of the branch conveyance path 46, and the paper fed into the paper reversing mechanism 48 is reversed here and sent out to the reversal conveyance path 26. The fed sheet is returned to the main conveyance path 28 in the sheet feeder 12 again. The paper fed into the discharge path 44 is carried out to the stacker 16. The stacker 16 includes a conveyance path 60 and a sheet storage unit 62. The paper carried out from the discharge path 44 is discharged and stored in the paper storage unit 62 via the transport path 60.

  Further, the ink jet recording apparatus 10 includes an electronic control unit 70. The electronic control unit 70 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, and a RAM that is used as a work area for data storage and program execution, and is provided in the inkjet recording apparatus 10. The recording of the image on the paper is controlled by controlling the operation of the actuator.

  FIG. 2 is a front view of the head unit 42, and FIG. 3 is a right side view of the head unit 42. 4 is a view of the head unit 42 as seen from the viewpoint P in FIG. FIGS. 2 to 4 show the head unit 42 at a position when ink is ejected onto the paper transported on the transport surface 40a to record an image. Hereinafter, the configuration of the head unit 42 will be described with reference to FIGS.

  The head unit 42 includes a main body unit 80, a first lifting / lowering unit 82, and a second lifting / lowering unit 83. The main unit 80 has a housing 84. The housing 84 includes a front plate 86, a rear plate 88, a connecting member 90, and a support member 91. The connecting member 90 connects the front plate 86 and the rear plate 88 with each other facing each other. The support member 91 is fixed to the front plate 86 in front of the front plate 86.

  The first lifting unit 82 includes a front plate 109, a rear plate 110, and a base plate 111. These are connected to each other so as to be U-shaped, and are arranged between the front plate 86 and the rear plate 88 so that the front plate 109 is located at the front, the rear plate 110 is located at the rear, and the base plate 111 is located below. .

  The first elevating unit 82 includes three line heads 118 that function as recording heads that eject ink and record images on paper. In addition, the line head 118 which the 1st raising / lowering unit 82 has may be two or more other than three, and may be single. Each of the line heads 118 has a large number of ejection holes arranged in a straight line on the ink ejection surface 118a to eject ink. In each of the three line heads 118, the ejection holes are arranged in a direction perpendicular to the paper transport direction (hereinafter referred to as “paper width direction”), and the gaps between the adjacent line heads 118 do not occur. Wrapped and arranged. Hereinafter, the three line heads 118 arranged in this way are referred to as a “line head group 120” as necessary.

  Since the image recording apparatus 14 is provided with the two head units 42, the two line head groups 120 are provided. The two line head groups 120 record images by ejecting inks of different colors from each other while being held at predetermined positions on the sheet conveyed on the conveyance surface 40a. For example, one head unit 42 may be provided so as to eject black ink, and the other head unit 42 may be provided so as to eject ink other than black, such as red.

  Three or more head units 42 may be provided. Also in this case, the line head group 120 of each of the plurality of head units 42 records an image by ejecting inks of different colors onto the paper transported on the transport surface 40a of the belt transport mechanism 40. For example, four head units 42 are provided, and each line head group 120 ejects Y (yellow), M (magenta), C (cyan), and K (black) ink onto a sheet to form a full-color image. It may be recordable. Of course, there is no limitation on the combination of the colors of ink ejected by each of the plurality of head units 42.

  Further, the line head 118 does not have to be arranged so that the ejection holes are arranged in the paper width direction. For example, the line head 118 is disposed at a predetermined angle with respect to the paper width direction. May be arranged in a row. The three line heads 118 are fixed to 111 such that the ink discharge surface 118a is exposed and faces downward. Further, instead of the line head 118, a recording head that simultaneously ejects ink on two or more lines may be used. Also in this case, the plurality of recording heads record images by ejecting inks of different colors while being held at predetermined positions.

  The first lifting / lowering unit 82 includes a plurality of guide rollers 112 and a rack gear 116. A guide plate 98 is fixed to the front plate 86 and the rear plate 88 so as to extend in the vertical direction. Three guide rollers 112 are provided on the front plate 109 and three on the rear plate 110 so as to sandwich the guide plate 98. Thus, the first elevating unit 82 is guided in the vertical direction by the guide plate 98 and the guide roller 112. Each of the front plate 86 and the rear plate 88 is provided with a guide roller 114 that restricts the movement of the first elevating unit 82 in the front-rear direction of the apparatus. Therefore, the guide plate 98 guide rollers 112 and 114 function as a guide mechanism for guiding the first elevating unit 82 in the vertical direction.

  The second lifting unit 83 includes a bracket 130 and an ink reservoir 132. The bracket 130 is provided so as to support the ink reservoir 132, and is supported by the support member 91 so as to be movable up and down. The ink reservoir 132 is connected to each of the three line heads 118 by a hose (not shown). The head unit 42 is detachably provided with an ink tank (not shown), and the ink reservoir 132 is also connected to the ink tank by a hose. To supply ink to each of the three line heads 118, ink is supplied from the ink tank to the ink reservoir 132, and the ink is temporarily stored. Such an ink reservoir 132 is well known, and a detailed description of its function and configuration is omitted.

  The main unit 80 further includes a line head moving mechanism 92 (recording head moving mechanism). The line head moving mechanism 92 includes a gear 94, a shaft 95, and a motor 96. The motor 96 drives the shaft 95 via the gear 97. Three gears 94 are provided on the shaft 95. A rack gear 116 is provided on each side surface of the front plate 109, the rear plate 110, and the bracket 130. Each of the three gears 94 meshes with each of the three rack gears 116. In this way, the line head moving mechanism 92 individually moves the line head group 120 close to and away from the transport surface 40a by the operation of the motor 96.

  A plurality of positioning pins 124 are provided on the lower surface of the base plate 111. On the other hand, the image recording apparatus 14 is provided with a positioning plate 126 in which positioning holes 126a are formed. The positioning pin 124 is inserted into the positioning hole 126a of the positioning plate 126 so that the line head group 120 is transported when the line head group 120 is in a position where an image can be recorded on the paper transported on the transport surface 40a. It is positioned at a predetermined position parallel to the surface 40a. Hereinafter, the position of the first lifting unit 82 at this time is referred to as a “first position”. The positioning pin 126 may be provided on the positioning plate 126, and the positioning hole may be provided in the base plate 111 of the first lifting unit 82.

  Each of the two head units 42 can be pulled out to the front of the apparatus by an accumulation rail (not shown). However, when the first elevating / lowering unit 82 is in the first position, the head unit 42 is not removable because the positioning pin 124 is inserted into the positioning hole 126a. In addition, since the housing 128 is positioned in front of the first lifting / lowering unit 82, the head unit 42 cannot be removed unless the first lifting / lowering unit 82 is further raised even when the positioning pin 124 is removed from the positioning hole 126a. It has become. Accordingly, each of the plurality of line head groups 120 is not removable when the first elevating unit 82 is in the first position.

  A recovery mechanism 152 is provided below the main unit 80. The recovery mechanism 152 is provided corresponding to each of the line head groups 120. Therefore, in the first embodiment, two recovery mechanisms 152 are provided. The recovery mechanism 152 executes a recovery process for recovering the ejection function of the corresponding line head. Specifically, when executing the recovery process by the recovery mechanism 152, the electronic control unit 70 first executes a purge process for ejecting ink from the ejection holes of the ink ejection surface 118a. Since the purge process is known, a detailed description thereof will be omitted.

  Next, a wiping process is executed in a state where ink is applied to the ink discharge surface 118a by the purge process. Specifically, the recovery mechanism 152 is provided with a wiper (not shown) that can move in the front-rear direction of the apparatus by the operation of a motor (not shown). The electronic control unit 70 executes the wiping process by operating the motor and moving the wiper while contacting the ink ejection surface 118a. Since this wiping process is also known, a description thereof will be omitted.

  When the first lifting / lowering unit 82 is in the first position, the recovery mechanism 152 is retracted to the left side of the first lifting / lowering unit 82. Hereinafter, this position is referred to as a “retracted position”. The recovery mechanism 152 is provided so as to be horizontally movable along the transport surface 40a by the moving mechanism 154. Specifically, the moving mechanism 154 includes a belt 156 and a roller 158. The belt 156 is driven so that the roller 158 moves in the horizontal direction by a motor (not shown). The recovery mechanism 152 is fixed to the belt 156 and moves horizontally along the transport surface 40a by the operation of the motor.

  The recovery mechanism 152 is provided with two guide rollers 160 on each of the front end face and the rear end face. The two guide rollers 160 are arranged in a horizontal line. In addition, a guide plate 162 is provided in the housing of the image recording apparatus 14 so as to extend in the horizontal direction at the front and rear of the apparatus. The recovery mechanism 152 is disposed so that the guide roller 160 is in contact with the upper surface of the guide plate 162. Thus, the guide roller 160 and the guide plate 162 guide the recovery mechanism 152 in the horizontal direction when the recovery mechanism 152 moves.

  In the first embodiment, the moving mechanism 154 is provided corresponding to each of the two recovery mechanisms 152. Therefore, each of the two recovery mechanisms 152 can advance to the advance position individually. A single moving mechanism 154 may be provided for the two recovery mechanisms 152. In this case, the two recovery mechanisms 152 are fixed to the same belt 156, and when the belt 156 is driven, both advance to the advanced position, and both retract to the retracted position. For this reason, when executing the recovery process on the line head group 120 of any head unit 42, the electronic control unit 70 moves the first lifting / lowering unit 82 of both head units 42 to the second position.

  FIG. 5 is a front view of the head unit 42 when the first elevating unit 82 is in the second position. FIG. 6 is a right side view of the head unit 42 when the first elevating unit 82 is in the second position. Here, in the first embodiment, the “second position” is a position separated from the conveyance surface 40a from the first position, and a position and a line head group for attaching and detaching the head unit 42 as will be described later. A position for advancing the recovery mechanism 152 between 120 and the transport surface 40a.

  The ink jet recording apparatus 10 is provided with a control panel (not shown), and the user can input a request for detachment of any of the head units 42 using the control panel. When the electronic control unit 70 acquires the input separation request, the electronic control unit 70 operates the motor 96 to move the first lifting unit 82 from the first position to the second position. At this time, the second lifting / lowering unit 83 also moves up the same distance as the first lifting / lowering unit 82.

  When the first lifting / lowering unit 82 is in the second position, the positioning pin 124 is removed from the positioning hole 126a, and the lowest position of the first lifting / lowering unit 82 is higher than the housing 128. For this reason, when the 1st raising / lowering unit 82 exists in a 2nd position, the head unit 42 is provided so that it can be pulled out ahead. That is, each of the line head groups 120 is detachably provided integrally with the ink reservoir 132 by being pulled out in the direction toward the ink reservoir 132 when the first elevating unit 82 is in the second position. As described above, since the first elevating unit 82 can be moved from the first position to the second position individually for each color, when it is desired to remove the head unit 42 of a certain color, a line of another color is obtained. The head group 120 can also be prevented from moving to the second position.

  A handle 105 is provided at the upper edge of each of the front plate 86 and the rear plate 88. When the user pulls the head unit 42 forward and removes the head unit 42 from the image recording apparatus 14, the user can carry the head unit 42 with the handle 105.

  The electronic control unit 70 determines whether or not a recovery execution condition for determining whether the line head group 120 needs a recovery process is satisfied while the power of the inkjet recording apparatus 10 is turned on. Since the recovery execution condition is publicly known, the description is omitted. When it is determined that the recovery execution condition is satisfied, the electronic control unit 70 first moves the first lifting unit 82 from the first position to the second position by the line head moving mechanism 92. When the corresponding line head group 120 is in the second position, the recovery mechanism 152 creates a space between the transport surface 40a and the ink discharge surface 118a, so that the recovery mechanism 152 advances between the transport surface 40a and the line head group 120. Can advance to position. The electronic control unit 70 causes the moving mechanism 154 to move the recovery mechanism 152 from the retracted position to the advanced position where the line head group 120 can execute the recovery process.

  FIG. 7 is a front view of the head unit 42 when the first lifting unit 82 is in the third position. FIG. 8 is a right side view of the head unit 42 when the first lifting unit 82 is in the third position. Here, in the first embodiment, the “third position” refers to the position of the head unit 42 where the recovery process of the line head 118 can be performed by the recovery mechanism 152.

  The electronic control unit 70 uses the line head moving mechanism 92 to move the line head group 120 corresponding to the recovery mechanism 152 at the advanced position from the second position to a third position where the recovery process by the recovery mechanism 152 is possible. Let As described above, the line head moving mechanism 92 moves each of the plurality of line head groups 120 between the first position, the second position, and the third position.

  The main unit 80 is provided with a first position sensor 100, a second position sensor 102, and a third position sensor 104. On the other hand, the first elevating unit 82 is provided with a protruding portion 129. The electronic control unit 70 determines that the first elevating unit 82 has reached the first position when the protruding portion 129 is detected by the first position sensor 100. When the protruding portion 129 is detected by the second position sensor 102, the electronic control unit 70 determines that the first elevating unit 82 has reached the second position. When the protruding portion 129 is detected by the third position sensor 104, the electronic control unit 70 determines that the first lifting unit 82 has reached the third position. Thus, the electronic control unit 70 can accurately determine which position the first lifting unit 82 has reached, and can appropriately stop the first lifting unit 82 at the position to be stopped.

  The upper surface plate 164 of the recovery mechanism 152 is provided with a plurality of positioning holes 164a. As the first elevating unit 82 moves from the second position to the third position, the positioning pin 124 is inserted into the positioning hole 164a. Thus, the positioning pins 124 position the line head group 120 at a predetermined position parallel to the transport surface 40a even when the line head group 120 is in the third position. Thus, by using the positioning pin 124 for positioning in both the first position and the third position, the cost can be suppressed as compared with the case where the positioning member is provided separately. The positioning pins 124 may be provided on the upper surface plate 164, and the positioning holes may be provided in the base plate 111 of the first elevating / lowering unit 82. In this case, the base plate 111 functions as a positioning member.

  As described above, when each of the head units 42 can be moved up and down individually and detachable, it is not easy to secure the ink ejection position accuracy as compared with the case where the head unit is fixed to the ink jet recording apparatus so as not to be moved up and down. For this reason, the head unit 42 according to the first embodiment holds unit-side correction data, and the inkjet recording apparatus 10 uses this to correct an image shift between the two head units 42. Yes. Hereinafter, this deviation correction method will be described.

  FIG. 9 is a functional block diagram of the inkjet recording apparatus 10 according to the first embodiment. FIG. 9 is realized by cooperation of a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, and software. Functional blocks are drawn. Therefore, these functional blocks can be realized in various forms by a combination of hardware and software.

  As described above, the head unit 42 may be replaced to change the color of the ink. On the other hand, the ink ejection position may be slightly different depending on each head unit 42 due to a manufacturing error or the like. Such an error of the head unit 42 also causes image shift.

  Therefore, in the first embodiment, each of the head units 42 holds unit-side correction data indicating the ink ejection position, and the electronic control unit 70 of the ink jet recording apparatus uses this to suppress image shift. Hereinafter, this procedure will be described in detail.

  The electronic control unit 70 of the inkjet recording apparatus 10 includes a data acquisition unit 200, an image shift correction unit 202, and a storage unit 204. On the other hand, the head unit 42 is provided with a data output unit 210 and a storage unit 212. The storage unit 212 stores unit data including unit side correction data indicating the ink ejection position. Information such as the number of sheets printed by the head unit 42 and an error history of the head unit 42 may be written in the storage unit 212 when the head unit 42 is mounted on the image recording apparatus 14. The data output unit 210 outputs unit data to the mounted inkjet recording apparatus 10.

  FIG. 10 is a diagram illustrating a data structure of unit data. The unit data includes color identification data, unit side correction data, and unit identification data. The color identification data is data for specifying the color of ink ejected by the head unit 42 or the color recorded on the paper when the head unit 42 ejects ink onto the paper, and includes a color code and approximate color data. . Since the color code is known, the description thereof is omitted. The approximate color data is RGB (Red, Green, Blue) data for displaying the approximate color of the color code on the display.

  In the first embodiment, since only two head units 42 can be mounted, for example, the head unit 42 that discharges black ink is mounted on one side, and special color inks that are individually prepared on the other side. It is conceivable to mount the head unit 42 for discharging. By including the color code and the approximate color data in the unit data in this way, it is possible to determine what color ink is to be ejected when the head unit 42 that ejects the special color ink is mounted. It becomes possible to transmit to the ink jet recording apparatus.

  The unit side correction data is used as data indicating the ink ejection position by the head unit 42. In the head unit 42, there is a possibility that the ink ejection hole is located at a position deviated from a normal position, which is a design position where the head unit 42 should originally be located, due to a tolerance of parts or a deviation at the time of assembly. Such a shift leads to a shift of images recorded by the two head units 42. For this reason, in the main body of the inkjet recording apparatus 10 to which the head unit 42 is attached, unit-side correction data is stored in the storage unit 212 of the head unit 42 in order to correct the deviation of images recorded by the two head units 42. ing.

  FIG. 11 is a diagram for explaining the contents of the unit-side correction data. FIG. 11 schematically shows a top view of the head unit 42. Hereinafter, as necessary, the sheet conveyance direction of the sheet conveyed on the conveyance surface 40a will be referred to as the Y direction, and the width direction perpendicular to the Y direction will be described as the X direction. Each of the three line heads 118 provided in the head unit 42 is arranged so as to record non-identical images in the X direction by being shifted from each other in the X direction as described above. The unit side correction data includes X direction correction data and Y direction correction data. The X direction correction data is data indicating the ejection position of each of the three line heads 118 in the X direction. The Y direction correction data is data indicating the ejection position of each of the three line heads 118 in the Y direction.

  In the first embodiment, when the three line heads 118 deviate from the normal position in the X direction, they are all shifted by the same length together with the casing of the head unit 42. For this reason, the unit-side correction data includes single X1 correction data as data representing the amount X1 of deviation from the normal positions of the three line heads 118 in the X direction. Each of the line heads 118 may be displaced in the length X direction different from the normal position. In this case, three pieces of data may be included in the unit-side correction data as X-direction correction data as the shift amounts of the recording positions of the two line heads 118.

  Hereinafter, the line heads 118 at the rear, center, and front of the apparatus are referred to as a first line head 118A, a second line head 118B, and a third line head 118C, respectively. In the first embodiment, each of the three line heads 118 can be shifted in the length Y direction different from the normal position. Therefore, the Y-direction deviation amount of the recording position of the first line head 118A is Y11, the Y-direction deviation amount of the recording position of the second line head 118B is Y12, and the Y-direction deviation of the recording position of the third line head 118C. The amount is Y13. The unit side correction data includes Y11 correction data, Y12 correction data, and Y13 correction data as data indicating Y11, Y12, and Y13. The amount of deviation in the Y direction is a positive value when shifted to the downstream side, and a negative value when shifted to the upstream side.

  X1 correction data, Y11 correction data, Y12 correction data, and Y13 correction data are experimentally acquired in advance by measuring the ink discharge position with respect to the positioning position of the head unit 42 before shipping the head unit 42 to the factory. It is stored in the storage unit 212 as side correction data.

  The unit identification data is data for identifying the head unit 42 and includes a product number and a manufacturing number. The unit identification data may include device identification data for identifying the inkjet recording device 10 and a lot number.

  Returning to FIG. When the head unit 42 is attached to the inkjet recording apparatus 10 with the power supply of the inkjet recording apparatus 10 turned on, the data output unit 210 transmits unit data to the main body of the inkjet recording apparatus 10. When the head unit 42 is attached when the power is turned off, the data output unit 210 transmits the unit data to the main body of the inkjet recording apparatus 10 when the power is turned on next time. The transmitted unit data is stored in the storage unit 204. The storage unit 204 stores main body side correction data indicating the relative attachment positions of the plurality of head units 42.

  The data acquisition unit 200 of the electronic control unit 70 acquires unit data from each of the two head units 42. The ink jet recording apparatus 10 is provided with a display (not shown). The electronic control unit 70 uses the color code included in the unit data to specify the color of the ink ejected by the head unit 42 and displays the name of the color on the display. Further, the electronic control unit 70 uses the approximate color data included in the unit data to display the approximate color of the ink on the display by color.

  FIG. 12 is a diagram for explaining the contents of the main body side correction data. FIG. 12 schematically shows a top view of the image recording apparatus 14 to which the head unit 42 is attached. Hereinafter, the upstream and downstream head units 42 are referred to as a first head unit 42A and a second head unit 42B. In the first embodiment, the displacement in the X direction with respect to the relative position where the second head unit 42B should originally be with respect to the first head unit 42A is X2, and the displacement in the Y direction is Y2. The main body side correction data includes X2 correction data indicating X2 and Y2 correction data indicating Y2.

  The X2 correction data and the Y2 correction data are defined as X2 correction data for actual X-direction deviation and Y2 correction data for Y-direction deviation when the head unit 42 for acquiring correction data on the main body side is mounted. Yes. Specifically, first, an image is recorded on a sheet only by the upstream head unit 42. Next, the head unit 42 mounted on the upstream side is removed, the head unit 42 is mounted again on the downstream side, and an image is similarly recorded on the paper. By using the same head unit 42 in this way, it is possible to measure an image shift without an element of a discharge position shift generated between the plurality of head units 42.

  Note that data indicating the positions of the two head units 42 relative to their normal positions may be used as the main body side correction data, instead of the relative positions of the two head units 42. This also makes it possible to grasp the relative positions of the two head units 42.

  Returning to FIG. The image misalignment correction unit 202 adjusts the ink ejection timing of each of the two head units 42 using the unit-side correction data included in the acquired unit data, thereby correcting the image recorded by the two head units 42. Correct the deviation. At this time, the image misalignment correction unit 202 corrects misalignment of images recorded by the plurality of head units 42 by using both the acquired unit side correction data and the held main body side correction data.

  Specifically, the image shift correction unit 202 includes an image shift calculation unit 206 and a recording head control unit 208. The image misalignment calculating unit 206 calculates an image misalignment amount that will occur unless correction is performed using both the unit side correction data and the main body side correction data. For example, the recording position of the second head unit 42B is {(X1 of the downstream head unit 42) − (X1 of the upstream head unit 42) + X2} in the X direction with respect to the recording position of the first head unit 42A. That is, it is shifted by {(X1 of the second head unit 42B) − (X1 of the first head unit 42A) + X2}.

  Further, the recording position of the first line head 118A on the downstream side is {(Y11 of the first line head 118A on the downstream side) − (upstream side of the first line head 118A on the downstream side) in the Y direction from the recording position of the first line head 118A on the upstream side. The deviation is Y11) + Y2} of the first line head 118A. Similarly, the recording position of the downstream second line head 118B is {(Y12 of the downstream second line head 118B)-(upstream side) in the Y direction from the recording position of the upstream second line head 118B. The second line head 118B is shifted by Y12) + Y2}. The recording position of the downstream third line head 118C is {(Y13 of the downstream third line head 118C)-(upstream side) in the Y direction from the recording position of the upstream third line head 118C. The third line head 118C is displaced by Y13) + Y2}. The image shift calculation unit 206 uses these equations to calculate shift correction amounts in the X direction and the Y direction.

  The recording head control unit 208 uses the calculated deviation correction amount to control the ink ejection timing by the line heads 118 of the two head units 42 to correct the deviation of the recorded image. Each of the two head units 42 is detachably attached to the inkjet recording apparatus 10. Further, when the head unit 42 is mounted on the main body of the inkjet recording apparatus 10, the head unit 42 records an image by ejecting ink while being held at a predetermined position with respect to the sheet conveyed on the conveyance surface 40 a. Is provided. As described above, by using both the unit side correction data and the main body side correction data, it is possible to more appropriately suppress the image shift.

(Second Embodiment)
FIG. 13A is a perspective view of the periphery of the first lifting unit 250 when the first lifting unit 250 is at the first position in the inkjet recording apparatus according to the second embodiment. FIG. 13B is a top view of the periphery of the first elevating unit 250 when the first elevating unit 250 is in the first position in the inkjet recording apparatus according to the second embodiment. Unless otherwise specified, the ink jet recording apparatus according to the second embodiment is the same as that of the first embodiment. Hereinafter, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The ink jet recording apparatus according to the second embodiment includes a first lifting unit 250 instead of the first lifting unit 82, a recovery mechanism 270 instead of the recovery mechanism 152, and a positioning plate 126. Two positioning members 260 are provided. The first lifting / lowering unit 250 is provided in the same manner as the first lifting / lowering unit 82 except that it includes a housing 252.

  One of the two positioning members 260 is disposed rearward and the other is disposed forward. The positioning member 260 has a unit placement surface 260a, a positioning surface 260b, and a taper guide 260c. The positioning member 260 is formed in a shape in which a part of a quadrangular columnar member is removed, and each of the unit placement surface 260a, the positioning surface 260b, and the taper guide 260c is formed in the removed portion. The unit placement surface 260a is formed on a flat surface, and a positioning surface 260b is configured by three surfaces that rise vertically from the edge of the unit placement surface 260a. The positioning member 260 is fixed to the casing of the inkjet recording apparatus so that the unit placement surface 260a is horizontal. The taper guide 260 c is provided as an inclined surface that continues from the upper end edge of the positioning surface 260 b to the upper surface of the positioning member 260.

  When the first elevating unit 250 is lowered from the second position to the first position, each of the rear end portion 252a and the front end portion 252b of the casing 252 is positioned by the tapered guides 260c of the two positioning members 260. Guided to 260b. When the lower surface of the first lifting unit 250 is placed on the unit placement surface 260a, the positioning of the first lifting unit 250 is completed. At this time, the first elevating unit 250 is positioned by the unit mounting surface 260a in the vertical direction and is positioned by the positioning surface 260b in the horizontal direction. Therefore, in this case, the rear end portion 252a and the front end portion 252b of the housing 252 also function as positioning members.

  FIG. 14A is a perspective view of the periphery of the first lifting unit 250 when the first lifting unit 250 is in the third position in the ink jet recording apparatus according to the second embodiment. FIG. 14B is a top view of the periphery of the first elevating unit 250 when the first elevating unit 250 is in the third position in the ink jet recording apparatus according to the second embodiment.

  As described above, when the recovery process is performed on the line head group 120, the first lifting unit 250 is first raised from the first position to the second position, and the recovery mechanism 270 is moved below the first lifting unit 250. After that, the first elevating unit 250 is lowered from the second position to the third position.

  Here, the recovery mechanism 270 is configured in the same manner as the recovery mechanism 152 according to the first embodiment except that the recovery mechanism 270 includes two positioning members 272. One of the two positioning members 272 is disposed rearward and the other is disposed forward. The positioning member 272 includes a unit placement surface 272a, a positioning surface 272b, and a taper guide 272c. The positioning member 272 is formed in the same manner as the positioning member 260 except that the length in the front-rear direction is longer than that of the positioning member 260. Accordingly, the unit placement surface 272a, the positioning surface 272b, and the taper guide 272c are formed in the same manner as the unit placement surface 260a, the positioning surface 260b, and the taper guide 260c, respectively.

  When the first elevating unit 250 is lowered from the second position to the third position, the rear end portion 252a and the front end portion 252b of the casing 252 are positioned by the tapered guides 272c of the two positioning members 272, respectively. Guided to 272b. When the lower surface of the first lifting unit 250 is placed on the unit placement surface 272a, the positioning of the first lifting unit 250 is completed. At this time, the first elevating unit 250 is positioned by the unit placement surface 272a in the vertical direction and is positioned by the positioning surface 272b in the horizontal direction. Thus, the rear end portion 252a and the front end portion 252b of the housing 252 are arranged so that the first elevating unit 250, that is, the line head group 120, can be used regardless of whether the first elevating unit 250 is in the second position or the third position. Functions as a positioning member for positioning at a predetermined position parallel to the transport surface 40a.

  The present invention is not limited to the above-described embodiments, and an appropriate combination of the elements of each embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can also be included in the scope of the present invention. Here are some examples.

  In a modification, the electronic control unit 70 acquires print information indicating whether each of the plurality of line head groups 120 is a line head that should record an image on a sheet or a line head that should avoid recording an image on a sheet. . Therefore, the electronic control unit 70 functions as information acquisition means.

  The line head moving mechanism 92 holds the line head that is supposed to record an image on the paper in the print information at the first position. On the other hand, the line head moving mechanism 92 moves the line head, which is supposed to avoid recording an image on the paper in the print information, to the second position. For example, it is assumed that two head units 42 that discharge black ink on one side and other colors such as red on the other side are mounted. In this case, when a print command for recording an image using only black ink is acquired, the electronic control unit 70 moves the first lifting unit 82 of the head unit 42 that discharges another color such as red to the second position. To rise. Accordingly, it is possible to suppress the frequency with which the sheet comes into contact with the first elevating unit 82, and it is possible to reduce the sheet conveyance error.

  In another modification, the storage unit 212 of the head unit 42 stores height data indicating the height of each ink discharge port of the line head 118 with respect to the normal position. The height data is included in the unit data and output to the main body side of the inkjet recording apparatus 10. The image misalignment correction unit 202 is recorded by the two head units 42 by adjusting the ink ejection timing of each of the two head units 42 using the acquired height data of each of the line heads 118. Correct image misalignment. This height data is experimentally acquired before the head unit 42 is shipped from the factory, and is stored in the storage unit 212 in advance.

  For example, when the height of the ink discharge port of the line head 118 is higher than the normal position, the image deviation calculation unit 206 calculates an increase in the time for the ink discharged from the ink discharge port to reach the recording surface of the paper. The recording head control unit 208 controls the ink ejection timing by the line head 118 so that the ink is ejected at an earlier timing by the increased time. The reverse is true when the height of the ink discharge port of the line head 118 is lower than the normal position. As a result, it is possible to realize more accurate image shift correction in consideration of the height of the ink discharge port of the line head 118.

  In another variation, the storage unit 204 of the electronic control unit 70 stores height data that indicates the mounting height for each normal position when the two head units 42 are mounted. The image misalignment correction unit 202 uses the height data stored in the storage unit 204 to adjust the ink ejection timing of each of the two head units 42, thereby recording the images by the two head units 42. Correct image misalignment. Thereby, it is possible to realize more accurate image shift correction in consideration of the height of the head unit 42 with respect to the normal position. Note that the image misalignment correction unit 202 uses both the height data held by the head unit 42 and the height data held by the electronic control unit 70 of the inkjet recording apparatus 10 so that the ink of each of the two head units 42 is used. The displacement of the image may be corrected by adjusting the discharge timing.

  In another modification, the storage unit 212 of the head unit 42 stores angle data indicating an inclination angle with respect to each normal position of the line head 118. The angle data is included in the unit data and output to the main body side of the inkjet recording apparatus 10. The image misalignment correction unit 202 adjusts the ink ejection timing of each of the two head units 42 using the acquired angle data of each of the line heads 118, thereby recording the images recorded by the two head units 42. Correct the deviation. As a result, more accurate image shift correction can be realized in consideration of the inclination of the line head 118 with respect to the normal position.

  In another modification, the storage unit 204 of the electronic control unit 70 stores angle data indicating the inclination with respect to each normal position when the two head units 42 are mounted. The image misalignment correction unit 202 uses the angle data stored in the storage unit 204 to adjust the ink ejection timing of each of the two head units 42, and is recorded by the two head units 42. Correct image misalignment. Accordingly, it is possible to realize more accurate image shift correction considering the inclination of the head unit 42 with respect to the normal position. Note that the image misalignment correction unit 202 uses the angle data held by the head unit 42 and the angle data held by the electronic control unit 70 of the ink jet recording apparatus 10 to eject ink from each of the two head units 42. The timing may be adjusted to correct the image shift.

  DESCRIPTION OF SYMBOLS 10 Inkjet recording device, 14 Image recording device, 40 Belt conveyance mechanism, 40a Conveying surface, 42 Head unit, 70 Electronic control part, 200 Data acquisition part, 202 Image deviation correction part, 204 Storage part, 206 Image deviation calculation part, 208 Recording head control unit, 210 data output unit, 212 storage unit.

Claims (1)

An ink jet recording apparatus that records an image by ejecting ink onto paper,
A plurality of head units for recording an image by ejecting ink while being held at a predetermined position with respect to a sheet being conveyed, each ejecting ink of a different color, and with respect to the ink jet recording apparatus A plurality of head units that can be attached and detached independently;
From each of the plurality of head units, and the unit-side correction data indicating information on the discharge position of the ink Okeru is information about the discharge position of the ink relative to a reference position within the head unit in the sheet conveying Direction, ink head unit ejects A data acquisition unit for acquiring color identification data for specifying the color of
A storage unit for holding a plurality of head units, the body-side correction data indicating the relative position of the sheet conveying Direction,
By adjusting the ink ejection timing of each of the plurality of head units based on the acquired unit-side correction data and the main body-side correction data held, the deviation of the image recorded by the plurality of head units can be reduced. An image shift correction unit to be corrected;
An ink jet recording apparatus comprising: a display unit configured to display information on a color specified from the acquired color identification data on a predetermined display.

Images