JP2011173279A - Image recording apparatus, image recording method, and dot formation position evaluating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording apparatus, an image recording method and a dot formation position evaluating method, wherein a landing position error is evaluated with high accuracy, and whether or not nozzles are in an abnormal state is more accurately determined based on the evaluation result. <P>SOLUTION: Grippers (80) are disposed in a recessed part (210) so as not to project over the circumferential surface (204) of a drawing barrel (44). A part of a recording medium (14) having a leading fixation area (14A) held by the grippers (80) is inserted into a pressing part (210). This area of the recording medium is larger than the area where the throw distance from the inkjet head (48) is supported on the circumferential surface. By forming a landing position evaluation pattern (280) on the portion, the positional error in the landing position evaluation pattern is relatively enlarged, accordingly, the landing position error may be evaluated with higher accuracy. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image recording apparatus, an image recording method, and a dot formation position evaluation method, and more particularly to a pattern formation technique for detecting a positional deviation of dots.

  As a general-purpose image recording apparatus, an ink jet recording apparatus that forms a desired image on a recording medium by an ink jet method is known. In an ink jet recording apparatus, an abnormal nozzle in which the ink ejection state is unstable causes various problems, and it is necessary to detect the presence or absence of an abnormality for each nozzle.

  For example, ink droplets are ejected from each of the nozzles provided in the inkjet head, the ink droplets that have landed on the recording medium are read using a reading device such as a scanner, and the error of the landing position is grasped based on the reading result. At the same time, the landing position error is evaluated. Examples of the processing after the evaluation of the landing position error include maintenance of the ink jet head, masking processing so as not to use the abnormal nozzle, service man call, head replacement, and the like.

  Patent Document 1 includes a drive unit that varies the distance between a nozzle and a printing material, and when a printed material for confirming the ink landing position (a printed material for confirmation) is produced, a printed material on which a predetermined pattern is formed. (Printed material) The distance between the nozzle and the substrate to be printed is made variable so that the distance between the nozzle and the substrate is increased compared to the case of producing the (printed material). It is disclosed that an ink landing position deviation can be recognized easily and accurately.

JP 2008-265206 A

  However, in order to recognize the landing position deviation for each nozzle, it is necessary to set the reading resolution of the reading device in accordance with the nozzle arrangement density. On the other hand, in order to read a predetermined area within a predetermined time, the reading resolution is limited mainly by the reading time performance of the reading device, and the reading resolution of the reading device is set to be small in order to cope with a practical measurement time. There must be. Since the in-line type reader is required to be quick (high speed), the reading resolution is set sufficiently lower than the recording resolution. With such a low-resolution reader, it is difficult to accurately determine normality or abnormality. In other words, if reading is performed at a resolution lower than the recording resolution, nozzles in the normal range may be determined to be abnormal, or nozzles outside the normal range may be determined to be normal, and abnormal nozzles can be reliably detected. It becomes difficult.

  In addition, the ink ejecting apparatus disclosed in Patent Document 1 includes a structure for moving the inkjet head in the Y-axis direction, or a printing stand for producing a different printed matter and a printing stand for producing a printed matter for confirmation. Are separately provided, and the configuration around the inkjet head becomes large or complicated.

  The present invention has been made in view of such circumstances, and an image recording apparatus capable of more accurately determining whether or not a landing position error has occurred and more accurately determining whether or not a nozzle is abnormal based on the evaluation result. And an image recording method and a dot formation position evaluation method.

  In order to achieve the above object, an image recording apparatus according to the present invention includes a recording head provided with a recording element for forming dots on a recording medium, and a drawing unit on which a recording image of the recording medium is drawn from the back side. A fixing member that is disposed on the inner side of the first surface so as not to protrude toward the recording head from the first surface to be supported, and that fixes an end of the recording medium; and A recording medium holding means having a second surface on which a blank area including an end portion fixed by the fixing member is fixed, and a distance between the recording head and the recording head is larger than a distance from the first surface; A moving means for relatively moving the recording medium held by the recording medium holding means and the recording head, and a dot formation position are evaluated by operating the recording element in the blank area fixed to the second surface. Do Characterized by comprising a drive control means for controlling the driving of the recording head to record the dot formation positions evaluation pattern fit.

  According to the present invention, the blank area of the recording medium is fixed on the second surface that is larger than the first surface that supports the drawing area, and the dot formation position evaluation pattern is recorded in the blank area. Therefore, the error of the dot formation position evaluation pattern is relatively enlarged, and it is possible to evaluate the error of the dot formation position with higher accuracy.

1 is an overall configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. The top view which shows the structure of the inkjet head mounted in the inkjet recording device shown in FIG. Enlarged view of FIG. The figure explaining the nozzle arrangement of the sub head shown in FIG. Sectional drawing which shows the three-dimensional structure of the subhead shown in FIG. 1 is a block diagram showing the configuration of a control system of the ink jet recording apparatus shown in FIG. The perspective view which shows the whole structure of the drawing cylinder of the inkjet recording device shown in FIG. FIG. 7 is a developed plan view showing an example of the structure of the vacuum channel of the drawing cylinder shown in FIG. A partially enlarged view of the drawing cylinder shown in FIG. Sectional drawing which shows the three-dimensional structure of the drawing cylinder shown in FIG. Plan view explaining layout of recording medium Explanatory drawing which illustrated typically the recording medium supported by the drawing cylinder shown in FIG. The figure explaining the example of calculation of the angle of the surface 204 shown in FIG. Explanatory drawing of the other aspect of the support of the recording medium shown in FIG. 12 is a partially enlarged view of the drawing cylinder shown in FIG. The figure which shows the structural example of the press roller applied to this example

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Description of overall configuration of inkjet recording apparatus]
FIG. 1 is a configuration diagram showing the overall configuration of an ink jet recording apparatus (image recording apparatus) according to the present embodiment. The ink jet recording apparatus 10 shown in the figure forms an image on the recording surface of the recording medium 14 based on predetermined image data using an ink containing a color material and an aggregating treatment liquid having a function of aggregating the ink. It is a two-liquid aggregation type on-demand type recording apparatus.

  The ink jet recording apparatus 10 mainly includes a paper supply unit 20, a treatment liquid application unit 30, a drawing unit 40, a drying processing unit 50, a fixing processing unit 60, and a discharge unit 70. Transfer cylinders 32, 42, 52, and 62 are provided as means for delivering the recording medium 14 conveyed upstream of the treatment liquid application unit 30, the drawing unit 40, the drying processing unit 50, and the fixing processing unit 60, and the treatment liquid. As means for conveying the recording medium 14 while holding the recording medium 14 in each of the coating unit 30, the drawing unit 40, the drying processing unit 50, and the fixing processing unit 60, impression cylinders 34, 44, 54, and 64 having a drum shape are provided. .

  The transfer cylinders 32, 42, 52, 62 and the impression cylinders 34, 44, 54, 64 are provided with grippers 80 </ b> A, 80 </ b> B that hold the front end portion (or rear end portion) of the recording medium 14 at predetermined positions on the outer peripheral surface. It has been. The structure in which the gripper 80A and the gripper 80B sandwich and hold the leading end portion of the recording medium 14 and the structure in which the recording medium 14 is transferred between the gripper provided in another impression cylinder or the transfer cylinder are the same, and The gripper 80 </ b> A and the gripper 80 </ b> B are arranged at symmetrical positions that are moved 180 ° in the rotation direction of the pressure drum 34 on the outer peripheral surface of the pressure drum 34.

  When the transfer cylinders 32, 42, 52, 62 and the impression cylinders 34, 44, 54, 64 are rotated in a predetermined direction with the gripper 80A, 80B holding the tip of the recording medium 14, the transfer cylinders 32, 42 are rotated. , 52, 62 and the outer circumference of the impression cylinders 34, 44, 54, 64, the recording medium 14 is rotated and conveyed.

  In FIG. 1, only the grippers 80 </ b> A and 80 </ b> B provided in the impression cylinder 34 are denoted by reference numerals, and the reference numerals of the other impression cylinders and the transfer cylinder grippers are omitted.

  When the recording medium (sheet) 14 accommodated in the paper supply unit 20 is fed to the treatment liquid application unit 30, the aggregation process is performed on the recording surface of the recording medium 14 held on the outer peripheral surface of the impression cylinder 34. A liquid (hereinafter simply referred to as “treatment liquid”) is applied. The “recording surface of the recording medium 14” is an outer surface in a state where the impression cylinders 34, 44, 54, 64 are held, and is a surface opposite to the surface held by the impression cylinders 34, 44, 54, 64. It is.

  Thereafter, the recording medium 14 to which the aggregation treatment liquid has been applied is sent to the drawing unit 40, and color ink is applied to the area of the recording surface to which the aggregation treatment liquid has been applied, thereby forming a desired image.

  Further, the recording medium 14 on which the image of the color ink is formed is sent to the drying processing unit 50, where the drying processing unit 50 performs the drying processing, and after the drying processing, the recording medium 14 is sent to the fixing processing unit 60 to perform the fixing processing. Applied. By performing the drying process and the fixing process, the image formed on the recording medium 14 is hardened. In this way, a desired image is formed on the recording surface of the recording medium 14, and after the image is fixed on the recording surface of the recording medium 14, it is conveyed from the discharge unit 70 to the outside of the apparatus.

  Hereinafter, each unit (the paper feeding unit 20, the processing liquid coating unit 30, the drawing unit 40, the drying processing unit 50, the fixing processing unit 60, and the discharging unit 70) of the inkjet recording apparatus 10 will be described in detail.

(Paper Feeder)
The paper feeding unit 20 is provided with a paper feeding tray 22 and a feeding mechanism (not shown), and the recording medium 14 is configured to be fed one by one from the paper feeding tray 22. The recording medium 14 sent out from the paper feed tray 22 is positioned by a guide member (not shown) so that its tip is positioned at a gripper (not shown) of the transfer drum (paper feed drum) 32 and temporarily stops.

(Processing liquid application part)
The treatment liquid application unit 30 holds the recording medium 14 delivered from the paper feed cylinder 32 on the outer peripheral surface, and conveys the recording medium 14 in a predetermined conveyance direction (treatment liquid drum (cylinder)) 34; And a treatment liquid coating device 36 that applies the treatment liquid to the recording surface of the recording medium 14 held on the outer peripheral surface of the treatment liquid cylinder 34. When the processing liquid cylinder 34 is rotated counterclockwise in FIG. 1, the recording medium 14 is rotated and conveyed in the counterclockwise direction along the outer peripheral surface of the processing liquid cylinder 34.

  The processing liquid coating device 36 shown in FIG. 1 is provided at a position facing the outer peripheral surface (recording medium holding surface) of the processing liquid cylinder 34. As a configuration example of the processing liquid coating device 36, a processing liquid container in which the processing liquid is stored, a pumping roller that is partially immersed in the processing liquid in the processing liquid container, and pumps up the processing liquid in the processing liquid container, and a pumping roller An embodiment including an application roller (rubber roller) that moves the pumped processing liquid onto the recording medium 14 is exemplified.

  In addition, an aspect is provided that includes an application roller moving mechanism that moves the application roller in the vertical direction (the normal direction of the outer peripheral surface of the treatment liquid cylinder 34), and can avoid collision between the application roller and the grippers 80A and 80B. preferable.

  The treatment liquid applied to the recording medium 14 by the treatment liquid application unit 30 contains a color material aggregating agent that aggregates the color material (pigment) in the ink applied by the drawing unit 40, and the treatment liquid is applied on the recording medium 14. And the ink come into contact with each other, the separation of the color material and the solvent in the ink is promoted.

  The treatment liquid application device 36 is preferably applied while measuring the amount of the treatment liquid to be applied to the recording medium 14, and the film thickness of the treatment liquid on the recording medium 14 is an ink droplet ejected from the drawing unit 40. It is preferable to make it sufficiently smaller than the diameter.

(Drawing part)
The drawing unit 40 holds an impression cylinder (drawing drum (cylinder)) 44 that holds and conveys the recording medium 14, a sheet pressing roller 46 for bringing the recording medium 14 into close contact with the drawing cylinder 44, and ink to the recording medium 14. Inkjet heads 48M, 48K, 48C, and 48Y are provided. Since the basic structure of the drawing cylinder 44 is the same as that of the processing liquid cylinder 34 described above, the description thereof is omitted here.

  The sheet pressing roller 46 is a guide member for bringing the recording medium 14 into close contact with the outer peripheral surface of the drawing cylinder 44, faces the outer peripheral surface of the drawing cylinder 44, and delivers the recording medium 14 between the transfer cylinder 42 and the drawing cylinder 44. It is disposed downstream of the position in the transport direction of the recording medium 14 and upstream of the ink jet heads 48M, 48K, 48C, and 48Y in the transport direction of the recording medium 14.

  The recording medium 14 transferred from the transfer cylinder 42 to the drawing cylinder 44 is pressed by the sheet pressing roller 46 when being rotated and conveyed with the leading end held by a gripper (reference numeral omitted), and the outer periphery of the drawing cylinder 44. Adhere to the surface. In this way, after the recording medium 14 is brought into close contact with the outer peripheral surface of the drawing cylinder 44, the recording medium 14 is sent to the printing area immediately below the ink jet heads 48M, 48K, 48C, 48Y without being lifted from the outer peripheral surface of the drawing cylinder 44. It is done.

  The inkjet heads 48M, 48K, 48C, and 48Y correspond to inks of four colors, magenta (M), black (K), cyan (C), and yellow (Y), respectively, and the rotation direction of the drawing cylinder 44 (see FIG. 1 are arranged in order from the upstream side (in the counterclockwise direction in FIG. 1), and the ink ejection surfaces (nozzle surfaces, denoted by reference numeral 114A in FIG. 5) of the ink jet heads 48M, 48K, 48C, 48Y are illustrated. The recording medium 14 is held so as to face the recording surface of the recording medium 14. Note that the “ink ejection surface (nozzle surface)” is a surface of the inkjet heads 48M, 48K, 48C, and 48Y that faces the recording surface of the recording medium 14, and is a nozzle that ejects ink described later (reference numeral in FIG. 4). This is a surface on which is formed.

  Further, in the inkjet heads 48M, 48K, 48C, 48Y shown in FIG. 1, the recording surface of the recording medium 14 held on the outer peripheral surface of the drawing cylinder 44 and the nozzle surfaces of the inkjet heads 48M, 48K, 48C, 48Y are substantially parallel. In such a manner, it is arranged to be inclined with respect to the horizontal plane.

  The inkjet heads 48M, 48K, 48C, and 48Y are full-line heads having a length corresponding to the maximum width of the image forming area in the recording medium 14 (the length in the direction orthogonal to the conveyance direction of the recording medium 14). The recording medium 14 is fixedly installed so as to extend in a direction orthogonal to the conveyance direction of the recording medium 14.

  On the nozzle surfaces of the inkjet heads 48M, 48K, 48C, and 48Y, nozzles for ejecting ink are formed in a matrix arrangement over the entire width of the image forming area of the recording medium 14.

  When the recording medium 14 is conveyed to the printing area immediately below the ink jet heads 48M, 48K, 48C, 48Y, the image data is converted into the area where the aggregation processing liquid of the recording medium 14 is applied from the ink jet heads 48M, 48K, 48C, 48Y. Based on this, ink of each color is ejected (droplet ejection).

  When droplets of the corresponding color ink are ejected from the inkjet heads 48M, 48K, 48C, 48Y toward the recording surface of the recording medium 14 held on the outer peripheral surface of the drawing cylinder 44, the processing is performed on the recording medium 14. The liquid and the ink come into contact with each other, and an aggregation reaction of the color material (pigment-based color material) dispersed in the ink or the color material (dye-based color material) to be insolubilized appears, and a color material aggregate is formed. As a result, movement of the color material in the image formed on the recording medium 14 (dot misalignment, dot color unevenness) is prevented.

  In addition, since the drawing cylinder 44 of the drawing unit 40 is structurally separated from the processing liquid cylinder 34 of the processing liquid application unit 30, the processing liquid does not adhere to the ink jet heads 48M, 48K, 48C, and 48Y. In addition, the cause of abnormal ink ejection can be reduced.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special colors are used as necessary. Ink may be added. For example, it is possible to add an inkjet head that discharges light-colored ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited.

(Dry processing part)
The drying processing unit 50 holds a pressure drum (drying drum (cylinder)) 54 that holds and conveys the recording medium 14 after image formation, and a solvent that performs a drying process for evaporating moisture (liquid component) on the recording medium 14. A drying device 56 is provided. Note that the basic structure of the drying cylinder 54 is the same as that of the processing liquid cylinder 34 and the drawing cylinder 44 described above, and a description thereof will be omitted here.

  The solvent drying device 56 is a processing unit that is disposed at a position facing the outer peripheral surface of the drying drum 54 and evaporates moisture present in the recording medium 14. When ink is applied to the recording medium 14 by the drawing unit 40, the liquid component (solvent component) of the ink and the liquid component (solvent component) of the processing liquid separated by the aggregation reaction between the processing liquid and the ink are placed on the recording medium 14. Since it remains, it is necessary to remove such a liquid component.

  The solvent drying device 56 performs a drying process for evaporating the liquid component existing on the recording medium 14 by heating with a heater, blowing with a fan, or a combination thereof, and removing the liquid component on the recording medium 14. Part. The amount of heating and the amount of air supplied to the recording medium 14 are appropriately set according to parameters such as the amount of moisture remaining on the recording medium 14, the type of the recording medium 14, and the conveyance speed (interference processing time) of the recording medium 14. Is done.

  When the drying process is performed by the solvent drying device 56, the drying cylinder 54 of the drying processing unit 50 is structurally separated from the drawing cylinder 44 of the drawing unit 40. Therefore, the inkjet heads 48M, 48K, 48C, and 48Y. In this case, it is possible to reduce the cause of abnormal ink ejection due to drying of the head meniscus by heat or air blowing.

  In order to exhibit the cockling correction effect of the recording medium 14, the curvature of the drying cylinder 54 is preferably 0.002 (1 / mm) or more. In order to prevent the recording medium from being curved (curled) after the drying process, the curvature of the drying cylinder 54 is preferably set to 0.0033 (1 / mm) or less.

  In addition, a means (for example, a built-in heater) for adjusting the surface temperature of the drying drum 54 may be provided, and the surface temperature may be adjusted to 50 ° C. or higher. By applying heat treatment from the back surface of the recording medium 14, drying is promoted and image destruction during the subsequent fixing process is prevented. In such an embodiment, it is more effective to provide means for bringing the recording medium 14 into close contact with the outer peripheral surface of the drying drum 54. Examples of the means for bringing the recording medium 14 into close contact include vacuum suction and electrostatic suction.

  The upper limit of the surface temperature of the drying cylinder 54 is not particularly limited, but from the viewpoint of safety of maintenance work such as cleaning ink adhering to the surface of the drying cylinder 54 (preventing burns due to high temperature). It is preferably set to 75 ° C. or lower (more preferably 60 ° C. or lower).

  The recording drum 14 is held on the outer peripheral surface of the drying drum 54 configured in this manner so that the recording surface of the recording medium 14 faces outward (that is, in a state where the recording surface of the recording medium 14 is convex). By performing the drying process while rotating and transporting, drying unevenness due to wrinkling and floating of the recording medium 14 is surely prevented.

(Fixing processing part)
The fixing processing unit 60 includes a pressure drum (fixing drum (cylinder)) 64 that holds and conveys the recording medium 14, and a heater 66 that heats the recording medium 14 on which an image is formed and from which the liquid is removed. And a fixing roller 68 that presses the recording medium 14 from the recording surface side. The basic structure of the fixing cylinder 64 is the same as that of the processing liquid cylinder 34, the drawing cylinder 44, and the drying cylinder 54, and a description thereof will be omitted here. The heater 66 and the fixing roller 68 are arranged at a position facing the outer peripheral surface of the fixing cylinder 64, and are sequentially arranged from the upstream side in the rotation direction of the fixing cylinder 64 (counterclockwise direction in FIG. 1).

  In the fixing processing unit 60, the recording surface of the recording medium 14 is subjected to a preheating process by the heater 66 and a fixing process by the fixing roller 68. The heating temperature of the heater 66 is appropriately set according to the type of recording medium, the type of ink (the type of polymer fine particles contained in the ink), and the like. For example, a mode in which the glass transition temperature and the minimum film forming temperature of the polymer fine particles contained in the ink are considered.

  The fixing roller 68 is a roller member for heating and pressurizing the dried ink to weld the self-dispersing polymer fine particles in the ink to form a film of the ink, and is configured to heat and press the recording medium 14. The Specifically, the fixing roller 68 is disposed so as to be in pressure contact with the fixing cylinder 64 and constitutes a nip roller with the fixing cylinder 64. As a result, the recording medium 14 is sandwiched between the fixing roller 68 and the fixing cylinder 64 and is nipped at a predetermined nip pressure, so that the fixing process is performed.

  As an example of the configuration of the fixing roller 68, there is an embodiment in which the fixing roller 68 is configured by a heating roller in which a halogen lamp is incorporated in a metal pipe such as aluminum having good thermal conductivity. By heating the recording medium 14 with such a heating roller, when thermal energy equal to or higher than the glass transition temperature of the polymer fine particles contained in the ink is applied, the polymer fine particles are melted to form a transparent film on the surface of the image. Is done.

  When pressure is applied to the recording surface of the recording medium 14 in this state, the polymer fine particles melted into the unevenness of the recording medium 14 are pressed and fixed, and the unevenness of the image surface is leveled, so that preferable glossiness can be obtained. A configuration in which a plurality of fixing rollers 68 are provided in accordance with the thickness of the image layer and the glass transition temperature characteristics of the polymer particles is also preferable.

  The surface hardness of the fixing roller 68 is preferably 71 ° or less. By making the surface of the fixing roller 68 softer, a follow-up effect can be expected for the unevenness of the recording medium 14 caused by cockling, and fixing unevenness due to the unevenness of the recording medium 14 can be more effectively prevented. .

  In the ink jet recording apparatus 10 shown in FIG. 1, an inline sensor 82 is provided at a subsequent stage (downstream in the recording medium conveyance direction) of the processing area of the fixing processing unit 60. The in-line sensor 82 is a sensor for reading an image formed on the recording medium 14 (or a check pattern formed in a blank area of the recording medium 14), and a CCD line sensor is preferably used.

  In the ink jet recording apparatus 10 shown in this example, the presence or absence of ejection abnormality of the ink jet heads 48M, 48K, 48C, and 48Y is determined based on the reading result of the inline sensor 82. Further, the in-line sensor 82 may include a measuring unit for measuring the moisture content, the surface temperature, the glossiness, and the like. In such an embodiment, parameters such as the processing temperature of the drying processing unit 50, the heating temperature of the fixing processing unit 60, and the pressure pressure are appropriately adjusted based on the moisture content, surface temperature, and gloss reading result, and the temperature inside the apparatus. The control parameter is adjusted as appropriate in accordance with the change and the temperature change of each part.

(Discharge part)
As shown in FIG. 1, a discharge unit 70 is provided following the fixing processing unit 60. The discharge unit 70 includes an endless transport chain 74 wound around the stretching rollers 72A and 72B, and a discharge tray 76 that stores the recording medium 14 after image formation.

  The recording medium 14 after the fixing process sent out from the fixing processing unit 60 is transported by the transport chain 74 and discharged to the discharge tray 76.

[Description of structure of inkjet head]
FIG. 2 is a schematic configuration diagram of an ink jet head applied to the present invention. FIG. 2 is a diagram (a plan perspective view of the head) of the recording surface of the recording medium viewed from the ink jet head. In addition, since the inkjet heads 48M, 48K, 48C, and 48Y shown in FIG. 1 have the same structure, in the following description, when it is not necessary to distinguish the inkjet heads 48M, 48K, 48C, and 48Y, these are used. Collectively, they are described as “inkjet head 100” or simply “head 100”.

  The head 100 shown in the figure forms a multi-head by connecting n sub-heads 102-i (i is an integer from 1 to n) in a line. Each sub head 102-i is supported by head covers 104 and 106 from both sides of the head 100 in the short direction. It is also possible to configure a multi-head by arranging the sub-heads 102 in a staggered manner.

  As an application example of a multi-head configured by a plurality of sub-heads, a full-line head corresponding to the entire width of a recording medium can be given. The full-line head has a plurality of nozzles (corresponding to the length (width) in the main scanning direction of the recording medium along the direction (main scanning direction) orthogonal to the moving direction (sub-scanning direction) of the recording medium. 4 is illustrated with reference numeral 108.) is arranged. An image can be formed on the entire surface of the recording medium by a so-called single-pass image recording method in which image recording is performed by scanning the head 100 having such a structure and the recording medium only once relatively.

  FIG. 3 is a partially enlarged view of the head 100. As shown in the figure, the sub head 102 has a substantially parallelogram-shaped planar shape, and an overlap portion is provided between adjacent sub heads. The overlap portion is a connecting portion of the sub heads, and is formed by nozzles in which dots adjacent to the sub heads 102-i are arranged in different sub heads in the arrangement direction of the sub heads 102-i (the horizontal direction in FIG. 2, the main scanning direction X shown in FIG. 3). The

  FIG. 4 is a plan view showing the nozzle arrangement of the sub head 102-i. As shown in the figure, each sub head 102-i has a structure in which nozzles 108 are arranged two-dimensionally, and a head including such a sub head 102-i is a so-called matrix head.

  In the sub-head 102-i shown in FIG. 4, a large number of nozzles 108 are arranged along a row direction W that forms an angle α with respect to the sub-scanning direction Y and a row direction V that forms an angle β with respect to the main scanning direction X. The substantial nozzle arrangement density in the main scanning direction X is increased. In FIG. 4, nozzle groups (nozzle rows) arranged along the row direction V are illustrated with reference numeral 110, and nozzle groups (nozzle arrays) arranged along the column direction W are illustrated with reference numeral 112. Is shown.

  FIG. 5 is a cross-sectional view showing a three-dimensional configuration of one channel of droplet discharge elements (ink chamber units corresponding to one nozzle 108) serving as a recording element unit. As shown in the figure, in the head 100 of this example, a nozzle plate 114 formed with nozzles 108 and a flow path plate 120 formed with flow paths such as a pressure chamber 116 and a common flow path 118 are laminated and joined. Consists of structure. The nozzle plate 114 forms a nozzle surface 114A of the head 100, and a plurality of nozzles 108 communicating with the pressure chambers 116 are two-dimensionally formed.

  The flow path plate 120 constitutes a side wall portion of the pressure chamber 116 and a flow path forming a supply port 122 as a throttle portion (most narrowed portion) of an individual supply path that guides ink from the common flow path 118 to the pressure chamber 116. It is a forming member. For convenience of explanation, the flow path plate 120 has a structure in which one or a plurality of substrates are stacked, although it is illustrated schematically in FIG.

  The nozzle plate 114 and the flow path plate 120 can be processed into a required shape by a semiconductor manufacturing process using silicon as a material.

  The common flow path 118 communicates with an ink tank (not shown) serving as an ink supply source, and ink supplied from the ink tank is supplied to each pressure chamber 116 via the common flow path 118.

  A diaphragm 124 constituting a part of the pressure chamber 116 (the top surface in FIG. 5) includes an individual electrode 126 and a lower electrode 128, and the piezoelectric body 130 is interposed between the individual electrode 126 and the lower electrode 128. A piezo actuator 132 having a sandwiched structure is joined. When the diaphragm 124 is formed of a metal thin film or a metal oxide film, it functions as a common electrode corresponding to the lower electrode 128 of the piezoelectric actuator 132. In the aspect in which the diaphragm is formed of a non-conductive material such as resin, a lower electrode layer made of a conductive material such as metal is formed on the surface of the diaphragm member.

  By applying a driving voltage to the individual electrode 126, the piezo actuator 132 is deformed to change the volume of the pressure chamber 116, and ink is ejected from the nozzle 108 due to a pressure change accompanying this. When the piezo actuator 132 returns to its original state after ink ejection, new ink is refilled into the pressure chamber 116 from the common flow path 118 through the supply port 122.

As shown in FIG. 4, the ink chamber unit having such a structure is latticed in a fixed arrangement pattern along a row direction V that forms an angle β with the main scanning direction X and a column direction W that forms an angle α with respect to the sub-scanning direction Y. The high-density nozzle head of this example is realized by arranging a large number in the shape. In such matrix arrangement, when the adjacent nozzle spacing in the sub-scanning direction and L _s, the main scanning direction that substantially each nozzle 108 are arranged linearly at a fixed pitch P = L s _/ tanθ equivalent Can be handled.

  The nozzle arrangement applicable to the present invention is not limited to the nozzle arrangement shown in FIG. 4. For example, a plurality of nozzles along the row direction along the main scanning direction and the column direction oblique to the main scanning direction are used. Is also applicable to a matrix array.

[Explanation of control system]
FIG. 6 is a block diagram showing a system configuration of the inkjet recording apparatus 10. As shown in the figure, the inkjet recording apparatus 10 includes a communication interface 140, a system control unit 142, a conveyance control unit 144, an image processing unit 146, a head driving unit 148, and an image memory 150, a ROM 152, and the like. .

  The communication interface 140 is an interface unit that receives image data sent from the host computer 154. The communication interface 140 may be a serial interface such as USB (Universal Serial Bus) or a parallel interface such as Centronics. The communication interface 140 may include a buffer memory (not shown) for speeding up communication.

  The system control unit 142 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 10 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. Furthermore, it functions as a memory controller for the image memory 150 and the ROM 152. That is, the system control unit 142 controls each unit such as the communication interface 140 and the conveyance control unit 144, performs communication control with the host computer 154, data read / write control with respect to the image memory 150 and the ROM 152, and the like. A control signal for controlling each unit is generated.

  Image data sent from the host computer 154 is taken into the inkjet recording apparatus 10 via the communication interface 140 and temporarily stored in the image memory 150. The image memory 150 is a storage unit that stores an image input via the communication interface 140, and data is read and written through the system control unit 142. The image memory 150 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The conveyance control unit 144 controls the conveyance timing and conveyance speed of the recording medium 14 (see FIG. 1) based on the print control signal generated by the image processing unit 146. 6 includes a motor for rotating the impression cylinders 34 to 64 in FIG. 1, a motor for rotating the transfer cylinders 32 to 62, a motor for a feeding mechanism of the recording medium 14 in the paper feeding unit 20, and a discharge unit 70. A motor for driving the tension roller 72A (72B) is included, and the conveyance control unit 144 functions as a driver for the motor.

  The image processing unit 146 has a signal (image) processing function for reading out image data stored in the image memory 150 and performing various processes and corrections for generating a print control signal from the image data. The control unit supplies the generated print data to the head drive unit 148. Necessary signal processing is performed in the image processing unit 146, and the ejection droplet amount (droplet ejection amount) and ejection timing of the head 100 are controlled via the head driving unit 148 based on the image data. Thereby, a desired dot size and dot arrangement are realized. The head drive unit 148 shown in FIG. 6 may include a feedback control system for keeping the drive conditions of the head 100 constant.

  The image memory 150 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The ROM 152 stores programs executed by the CPU of the system control unit 142 and various data necessary for control (data for ejecting test charts, waveform data for detecting abnormal nozzles, waveform data for drawing and recording, abnormal nozzle information) Etc.) are stored. The ROM 152 may be a non-rewritable storage unit, or may be a rewritable storage unit such as an EEPROM.

  An overview of the flow of processing from image input to print output is as follows. Image data to be printed is input from the outside via the communication interface 140 and stored in the image memory 150. At this stage, for example, RGB multivalued image data is stored in the image memory 150.

  In the inkjet recording apparatus 10, a pseudo continuous tone image is formed by human eyes by changing the droplet ejection density and dot size of fine dots by ink (coloring material). It is necessary to convert to a dot pattern that reproduces the gradation (shading of the image) as faithfully as possible. Therefore, the original image (RGB) data stored in the image memory 150 is sent to the image processing unit 146 via the system control unit 142, and is subjected to density data generation, correction processing, and ink ejection data generation for each ink color. Converted to dot data.

  That is, the image processing unit 146 performs processing for converting the input RGB image data into dot data of M, K, C, and Y colors. Thus, the dot data generated by the image processing unit 146 is stored in an image buffer memory (not shown). This dot data for each color is converted into MKCY droplet ejection data for ejecting ink from the nozzles of the head 100, and ink ejection data to be printed is determined.

  In this way, the drive waveform output from the head drive unit 148 is added to the head 100, whereby ink is ejected from the corresponding nozzle 108. An image is formed on the recording medium 14 by controlling ink ejection from the head 100 in synchronization with the conveyance speed of the recording medium 14.

  In addition, the inkjet recording apparatus 10 includes a processing liquid application control unit 160, a drying processing control unit 162, and a fixing processing control unit 164, and in accordance with instructions from the system control unit 142, the processing liquid application unit 30 and the drying processing unit, respectively. The operation of each unit of the processing unit 50 and the fixing processing unit 60 is controlled.

  Based on the print data obtained from the image processing unit 146, the processing liquid application control unit 160 controls the processing liquid application timing and also controls the application amount of the processing liquid. The drying process control unit 162 controls the timing of the drying process and also controls the processing temperature, the air flow rate, and the like. The fixing process control unit 164 controls the temperature of the heater 66 of the fixing process unit 60 and fixes the fixing process. The pressing of the roller 68 is controlled.

  The inline detection unit 166 is a processing block including the inline sensor 82 illustrated in FIG. 1 and a signal processing unit that performs predetermined signal processing such as nozzle removal, amplification, and waveform shaping on the read signal output from the inline sensor 82. . The system control unit 142 determines whether there is an ejection abnormality of the head 100 based on the detection signal obtained by the inline detection unit 166.

  That is, the system control unit 142 sends the test chart read from the inline detection unit 166 and the read data of the landing position evaluation pattern to the determination unit 168. The determination unit 162 grasps the landing position error, dot size error, density error, and the like from the read data, and determines whether there is an abnormality for each nozzle. The processing function can be realized by ASIC, software, or an appropriate combination. Information (data) of the abnormal ejection nozzle obtained by the determination unit 168 is stored in a predetermined memory. For example, by using the storage area of the ROM 152, it is possible to use the ROM 152 as a memory for storing ejection abnormal nozzle information.

  Nozzles that are determined to be abnormal (discharge abnormal nozzles that cannot perform normal discharge) are masked (undischargeable) and are not used. Other nozzles are used for drawing with masked nozzles. Is done. In addition, when the number of masked nozzles or the distribution of masked nozzles exceeds a predetermined reference, the system control unit 142 sends a command signal to each part of the apparatus to perform maintenance of the head 100. Send it out. The maintenance of the head 100 includes processes such as wiping of the nozzle surface 114A (see FIG. 5) and suction of the nozzle. Furthermore, if the specified performance cannot be recovered even after performing processing such as wiping and nozzle suction, a serviceman needs to be maintained (serviceman call), or a head needs to be replaced Is notified.

  The inline sensor 82 mounted on the ink jet recording apparatus 10 shown in this example reads at a resolution lower than the recording resolution of the ink jet head 48. For example, while the recording resolution of the head 100 is 2400 dpi, the reading resolution of the inline sensor 82 is about 400 to 600 dpi. Note that the in-line sensor 82 may be configured to read a full width of the drawing area by enlarging a reading width smaller than the full width of the drawing area of the recording medium 14 using a magnifying optical system. Moreover, it is good also as a structure containing a some image sensor.

  The operation unit 170 as a user interface includes an input device 172 and a display unit (display) 178 for an operator (user) to perform various inputs. The input device 172 can employ various forms such as a keyboard, a mouse, a touch panel, and buttons. By operating the input device 172, the operator can perform input of printing conditions, selection of image quality mode, input / editing of attached information, search of information, and various information such as input contents and search results. This can be confirmed through display on the display unit 176. The display unit 176 also functions as means for displaying a warning such as an error message.

  The pump control unit 180 controls on / off of the vacuum pump 182 that generates a negative pressure for holding and fixing the recording medium 14 on the peripheral surfaces of the pressure drums 34, 44, 54, and 64 and the rotational speed. That is, the vacuum pump 182 is controlled via the pump control unit 180 based on the command signal sent from the system control unit 142. An individual vacuum pump may be provided for each of the impression cylinders 34, 44, 54, and 64, or a common vacuum pump may be provided for a plurality of impression cylinders. In FIG. 6, a plurality of vacuum pumps provided in the inkjet recording apparatus 10 are represented and denoted by reference numeral 182.

[Description of the drawing cylinder]
(Outline configuration)
FIG. 7 is a perspective view showing the entire structure of the drawing cylinder 44. A drawing cylinder 44 shown in the figure is a rotating body member that is connected to a rotation mechanism (not shown) and is rotatable around the rotation shaft 202 supported by a bearing (not shown) by the operation of the rotation mechanism. .

  Further, the peripheral surface 204 of the drawing cylinder 44 functions as a medium support surface that supports the recording medium 14 (see FIG. 1) from the back side, and generates a large number of suctions that generate suction pressure (negative pressure) that acts on the recording medium 14. It has a medium support region 206 provided with holes (in FIG. 7, a separate illustration is omitted, and a reference numeral 250 is attached in FIG. 9 and is shown separately). In the medium support region 206 shown with dot hatching in FIG. 7, a belt-like non-opening portion 208 not provided with suction holes is provided along the circumferential direction over a length that is approximately ½ of the entire circumference. The non-opening portion 208 blocks the back of a throttle portion (not shown in FIG. 7, not shown in FIG. 8 and indicated by reference numeral 234). Note that a medium support region having a similar structure is provided on the back side not shown in the perspective view of FIG.

  The drawing cylinder 44 shown in FIG. 7 is provided with a vacuum channel for suction that communicates with a suction hole provided in the medium support region 206. This vacuum flow path includes a vacuum piping system (pipe, joint, etc.) (not shown in FIG. 2) provided on the side surface 222 of the drawing cylinder 44 and a vacuum flow path (not shown) provided inside the rotation shaft 202 of the drawing cylinder 44. It is connected to a vacuum pump 182 (not shown in FIG. 7, refer to FIG. 6) provided outside the drawing cylinder 44 via the drawing. When the vacuum pump 182 is operated to generate a vacuum (negative pressure), an adsorption pressure is applied to the recording medium 14 through the adsorption hole and the vacuum channel. That is, the drawing cylinder 44 is configured such that the recording medium 14 is fixedly held on the peripheral surface (medium support surface) 104 by a vacuum (air) adsorption method.

  On the outer peripheral surface of the drawing cylinder 44, two concave portions 210 are formed over the entire length in the axial direction, and the two concave portions 210 are arranged so that their rotational positions are shifted by approximately 180 °. For convenience of illustration, only one of the two recesses 210 is shown in FIG. The concave portion 210 is provided with a plurality of grippers 80 that function as clamping means for clamping the leading end portion of the recording medium 14, and a gripper opening / closing mechanism 212 for opening and closing the grippers 80.

  The gripper 80 has a claw shape (substantially L shape, see FIG. 12), and the recording medium 14 is sandwiched between the front end of the recording medium 14 and the claw base 213 that supports the recording medium 14 from the back side. It is comprised so that the front-end | tip part may be clamped. The plurality of grippers 80 are arranged at equal intervals along the axial direction, and are arranged over a length corresponding to the maximum width of the recording medium 14. The gripper 80 is accommodated in the recess 210 so as not to protrude from the peripheral surface 204 of the drawing cylinder 44.

  A gripper opening / closing mechanism 212 that opens and closes the gripper 80 supports a gripper base (not shown) that supports the gripper 80, an opening / closing shaft 214 to which the gripper base is coupled, and the opening / closing shaft 214 rotatably with respect to the drawing cylinder 44. The shaft blanket 216 includes an opening / closing arm 220 that connects the opening / closing shaft 214 and the cam follower 218. The cam follower 218 and the opening / closing arm 220 are provided outside the side surface 222 of the drawing cylinder 44.

  In the gripper opening / closing mechanism 212 shown in this example, the cam follower 218 moves along a predetermined cam curve according to the operation of a driving source (motor) (not shown), and the opening / closing shaft 214 connected to the opening / closing arm 220 rotates. The gripper 80 is configured to open and close according to the rotation of the opening and closing shaft 214.

  In the ink jet recording apparatus 10 shown in the present example, the ink droplets of the recording medium 14 discharged from the nozzles 108 are submerged inside the recess 210 from the peripheral surface 204 of the drawing cylinder 44 of the recording medium 14. A landing position evaluation pattern for evaluating the landing position error in the width direction orthogonal to the transport direction is formed. With such a configuration, the landing position error is enlarged, the landing position error can be easily evaluated, the accuracy of determination of head maintenance based on the evaluation of the landing position error is increased, and the image quality of the recorded image is improved. Details of the formation of the landing position evaluation pattern and the evaluation of the landing position error will be described later.

(Description of vacuum flow path)
Next, the vacuum flow path applied to the drawing cylinder 44 shown in this example will be described. Note that the vacuum flow path described below is merely an example, and other configurations can be applied.

  FIG. 8 is a development view showing the internal structure of the medium support area 206 (the structure on the back side of the suction holes provided in the medium support area 206) shown with dot hatching in FIG. 2. The horizontal direction in the figure is the axial direction, the vertical direction is the circumferential direction, the lower side in the figure is the leading end side in the conveyance direction of the recording medium 14, and the position labeled “CL” is the center in the axial direction Position.

  As shown in FIG. 8, a large number of suction grooves 230 and 232 are provided inside the medium support region 206, and the large number of suction grooves 230 and 232 are denoted by reference numerals 240 to 246 and indicated by a thick frame 4. Arranged to correspond to the size of the type of recording medium.

The length W ₁ in the circumferential direction of the suction groove 230 provided at the position (upper side in the drawing) corresponding to the center portion and the rear end portion of the recording medium 14 is a position corresponding to other than the rear end portion of the recording medium 14. is larger than the groove width W ₂ of the (in the drawing, the central and lower) suction grooves 232 provided in the. On the other hand, the groove length (axial length) L ₁ of the suction groove 230 and the groove length L ₂ of the suction groove 232 are substantially the same. With this structure, the amount of air at the rear end portion of the recording medium 14 can be made larger than that at the central portion and the front end portion, and the rear end portion of the recording medium 14 can be effectively prevented from being lifted or turned up.

  As shown in FIG. 8, the suction groove 230 and the suction groove 232 have a structure in which one end portion in the axial direction is closed, and a throttle portion 234 is provided at the other end portion. In addition, one throttle portion 234 communicates with the suction groove 230 or the suction groove 232 having different ends. Note that only one (inner side) of the narrowed portions 234 ′ disposed at both ends in the axial direction communicates with the suction grooves 230 and 232, and the other (outer side) has a closed structure.

  The narrowed portion 234 has a groove width (cross-sectional area) smaller than the groove width of the suction grooves 230 and 232, and is disposed on the back side of the non-opening portion 208 shown in FIG. The peripheral surface 204 side) is closed. That is, the throttle portion 234 (234 ') has a function of restricting the flow rate of air flowing through the suction grooves 230 and 232 and preventing the pressure that attracts the recording medium 14 from being lost.

  In the adsorption groove 230, ribs 236 and 238 having a convex shape are provided. The ribs 236 and 238 have an island-like pattern, and the height thereof is substantially equal to the depth of the suction grooves 230 and 232. The rib 236 is formed in a broken line shape parallel to the axial direction. In addition, a plurality of rows (rib rows in FIG. 3) are formed in parallel in the suction groove 230 in a row of ribs 236 arranged in a dashed line along the axial direction. The interval between the rib rows is substantially equal to the groove width of the suction groove 232. Further, ribs 238 are formed in broken lines along the circumferential direction at the cuts of the ribs 236 aligned in parallel with the axial direction.

  As described above, by providing the divided island-like ribs 236 and 238, it is possible to prevent the dent on the arc surface of the recording medium 14 attracted and held in the medium support area 206, and to make the slow distance uniform. can do. In addition, since air can move through the gaps between the divided ribs 236 and 238, the air flow rate in the adsorption groove 230 can be secured.

  A plurality of ribs 238 formed along the circumferential direction are arranged in the suction groove 232 along the axial direction. A gap is provided between the wall of the suction groove 232 and the rib 238, and the air can move through the gap.

  FIG. 9 is a partially enlarged view of the medium support area 206. As shown in the figure, the medium support region 206 is provided with a number of suction holes 250. The arrangement relationship between the suction holes 250 and the suction grooves 232 (230) is as shown in the figure. The arrangement pattern of the suction holes 250 preferably corresponds to the pattern of the suction grooves 232 (230) on the back surface, but some of the suction holes 250 may not communicate with the suction grooves 232 (230).

  Moreover, the width | variety of the aperture | diaphragm | squeeze part 234 is narrower than the width | variety of the adsorption | suction groove | channel 232, and the depth of the aperture | diaphragm | squeeze part 234 and the adsorption | suction groove | channel 232 (230) is substantially the same. That is, the flow passage cross-sectional area of the throttle portion 234 is smaller than the flow passage cross-sectional area of the suction groove 232, and the flow rate of air flowing through the suction groove 232 (230) is limited by the throttle portion 234.

  The drum suction groove 252 illustrated by a broken line in FIG. 9 communicates with the throttle portion 234 (234 ′) and communicates with a vacuum channel provided inside the drawing cylinder 44 through a drum suction hole (not shown). . Further, the peripheral surface 204 side is closed by the non-opening portion 208 (see FIG. 7) similarly to the throttle portions 234 and 234 '.

  FIG. 10 is a cross-sectional view (a cross-sectional view taken along the line AA in FIG. 9) showing the three-dimensional structure of the drawing cylinder 44. As shown in the figure, the drawing cylinder 44 includes a suction layer 260 provided with suction holes 250, a suction layer 230, 232, an intermediate layer 262 provided with throttle portions 234, 234 ', and a main body provided with a drum suction groove 252. It is possible to consider separately in the part 264.

  For example, the adsorption layer 260 and the intermediate layer 262 are formed of a single sheet-like member, and the intermediate layer 262 is stacked and wound around a main body 264 provided with a predetermined flow path structure, a rotation mechanism, and the like. A structure in which the adsorption layer 260 is stacked and wound around the layer 262 can be employed. In addition, the adsorption layer 260 and the intermediate layer 262 are integrated, and a single sheet-like member in which the adsorption holes 250, the adsorption grooves 230 and 232, and the narrowed portions 234 and 234 ′ are formed is stacked on the main body portion 264 and wound. May be attached.

  Note that the thickness of the adsorption layer 260 is preferably larger than the thickness of the intermediate layer 262. In the embodiment shown in the figure, the thickness of the intermediate layer 262 with respect to the thickness of the adsorption layer 260 is approximately ½. The intermediate layer 262 is a predetermined thickness portion on the back side of the sheet on which patterns such as the suction grooves 230 and 232 and the ribs 236 and 238 described with reference to FIG. 8 are formed. The thinner the intermediate layer 262, the higher the adsorption force can be obtained with a smaller negative pressure. However, if the intermediate layer 262 is excessively thin, clogging with foreign matters such as paper dust and dust tends to occur. Considering such conditions, the thickness of the intermediate layer 262 is preferably about 0.05 mm to 0.5 mm.

  The adsorption layer 260 needs to be thick enough to ensure that it does not sink due to the adsorption pressure even when the ribs 236 and 238 are not present below, and the adsorption layer 260 is wound around and fixed to the peripheral surface of the main body 264. Therefore, a certain degree of flexibility is required. For example, the thickness of the adsorption layer 260 manufactured using stainless steel is preferably 0.1 mm to 0.5 mm, and more preferably about 0.2 to 0.3 mm. In the case of using a material other than stainless steel, it is designed to have an appropriate thickness in consideration of the rigidity and flexibility of the material to be used.

  The planar shape of the suction hole 250 may be a shape other than a circle such as an ellipse or a polygon. A structure in which the suction hole 250 is omitted is also possible. However, regardless of which structure is applied, it is necessary to have a structure in which the back side (peripheral surface 204 side) of the throttle parts 234 and 234 ′ is always closed, and a structure in which the throttle parts 234 and 234 ′ are not directly opened to the atmosphere. .

  The vacuum flow path described above is open when the recording medium having a size smaller than the maximum size recording medium is used (even if the suction holes 250 and the suction grooves 230 and 232 that are open to the atmosphere) exist. The suction pressure does not drop from the suction holes 250 and the suction grooves 230 and 232 that are opened by the action of the throttle portions 234 and 234 ′, and the predetermined suction pressure is maintained for the recording media 14 of various sizes. Is possible.

[Description of landing position evaluation pattern formation]
Next, a dedicated pattern (landing position evaluation) for evaluating an error in the landing position of ink droplets ejected from the ink jet heads 48M, 48K, 48C, and 48Y (hereinafter sometimes simply referred to as the ink jet head 48). The formation (evaluation) of the pattern (shown with reference numeral 280 in FIG. 11) will be described in detail.

  In the inkjet recording apparatus 10 shown in this example, the slow distance between the recording medium 14 supported on the peripheral surface 204 of the drawing cylinder 44 and the inkjet head 48 is 1 mm or less, and the slow distance between the recording medium 14 and the inkjet head 48 is. The normal range of the landing position error on the recording medium 14 when is 1 mm is within ± 3 μm. That is, the normal range of the discharge angle is within atan (0.003 (mm) / 1 (mm)) = 3 mrad. A nozzle having an error exceeding the normal range is determined as an abnormal nozzle.

  In order to accurately determine whether or not the landing position error is within a normal range within ± 3 μm for each nozzle, it is necessary to read the landing position evaluation pattern in the submicron order, but it has a reading resolution of about 400 to 600 dpi. When the in-line sensor 82 (see FIG. 1) is used, only reading accuracy of about several μm to several tens of μm can be obtained. On the other hand, if the landing position evaluation pattern can be read with a reading resolution of about 2400 dpi, the landing position evaluation pattern can be evaluated with an accuracy of about 1 μm if the processing of the read data is devised.

  That is, if the landing position error on the recording medium can be enlarged at least 5 times or more, it is determined whether or not the ejection angle is within the normal range (within 3 mrad) from the reading result with a reading resolution of about 400 to 600 dpi. Is possible. Therefore, in the inkjet recording apparatus 10 shown in this example, the landing position evaluation pattern is applied to the portion of the recording medium 14 that has entered the recess 210 using the recess 210 (see FIG. 7) formed in the drawing cylinder 44. By forming, the slow distance between the area where the landing position evaluation pattern of the recording medium 14 is formed and the inkjet head 48 is enlarged, and the error between dots in the landing position evaluation pattern is relatively enlarged.

  FIG. 11 is a plan view showing the layout of the recording medium 14. As shown in the figure, the recording medium 14 includes a tip fixing area 14A sandwiched (fixed) by a gripper 80 (see FIG. 7), a landing position evaluation pattern formation area 14B in which a landing position evaluation pattern 280 is formed, It includes a user layout area 14C where a desired image is recorded and a trailing edge blank area 14D which is a receiving area for ink ejected by dummy jet processing. The recording medium 14 is supported so that the boundary 14E between the landing position evaluation pattern formation area 14B and the user layout area 14C is located on the peripheral surface 204 of the drawing cylinder 44.

  The tip fixing area 14A and the landing position evaluation pattern formation area 14B constitute a tip margin area. That is, the recording medium 14 includes a front end margin area, a user layout area (drawing area) 14C, and a rear end margin area 14D.

  FIG. 12 is an explanatory diagram schematically showing the recording medium 14 supported by the drawing cylinder 44. In FIG. 12, the direction penetrating the paper surface is the axial direction. As shown in FIG. 11, the tip fixing area 14A of the recording medium 14 is fixed by the gripper 80 disposed inside the recess 210, so that a predetermined range from the tip fixing area 14A of the recording medium 14 is the inside of the recess 210. 204A (second surface). By setting the portion supported by the surface 204A of the recording medium 14 as the landing position evaluation pattern formation area 14B, the slow distance between the ink jet head 48 and the landing position evaluation pattern formation area 14B is expanded, and errors in the landing position evaluation pattern are reduced. It can be enlarged.

  For example, the landing position evaluation pattern 280 (see FIG. 11) is formed at a position where the depth α from the peripheral surface 204 is 4 mm in the portion supported by the surface 204A of the recording medium 14, whereby the landing position evaluation is performed. The position error in the pattern 280 can be enlarged five times. That is, the landing position evaluation pattern 280 is formed at a position satisfying the relationship of α ≧ (recording resolution / reading resolution) − (slow distance in the user layout area 14C of the ink jet head 48 and the recording medium 14). Since the position error at 280 is enlarged corresponding to the ratio of the recording resolution to the reading resolution, the landing position evaluation pattern 280 is read using the inline sensor 82 having a reading resolution sufficiently lower than the recording resolution of the inkjet head 48. Even if it is performed, it is equivalent to reading the landing position evaluation pattern 280 with a reading resolution comparable to the recording resolution, and it is possible to accurately determine whether or not the ejection angle of each nozzle is within the normal range. Is possible.

  The length of the tip fixing area 14A held by the gripper 80 is 2 mm to 4 mm, and the distance from the tip of the gripper 80 to the boundary between the recess 210 and the peripheral surface 204 is 10 mm or more and 20 mm or less. By setting the angle of the surface 204A with respect to the horizontal plane to 20 ° or more (more preferably 30 ° or more), the condition α described above can be satisfied, and a drawing area for the landing position evaluation pattern 280 can be secured.

Here, describing calculation example of the angle theta ₁ surface 204A with respect to the horizontal plane (shown by a dot-dashed line). FIG. 13 is a diagram illustrating a calculation example of the angle θ ₁ of the surface 204A with respect to the horizontal plane. The illustrated parameters are used in calculating the angle θ ₁ . The angle θ ₂ is an angle formed by a perpendicular (shown by a one-dot broken line) passing through the axis of the drawing cylinder 44 and the tip position of the gripper 80, and L ₁ is the recess 210 and the peripheral surface 204 from the tip position of the gripper 80 on the horizontal plane. the distance to the boundary and, _{L 2} is the distance from the nozzle face 114A to the axis O of the drawing drum 44, _{L 3} is the distance from the nozzle face 114A to the surface 204A, the _{L 4} are surface 204 to the axis O of the drawing drum 44 Is the distance.

When the distance (slow distance, L ₃ -D) from the nozzle surface 114A to the peripheral surface 204 is 1 mm, θ ₁ that satisfies D ≧ 5 mm may be obtained. The radius R of the drawing cylinder 44 is 255 mm.

When L ₁ = 11.8 mm, L ₂ = 255.3 mm, L ₃ = 5.9 mm, L ₄ = 219.4 mm, θ ₂ = 3 °, and θ ₁ is 30 °, D = 5.6 mm And see the above conditions. At this time, the distance from the tip position of the gripper 80 to the boundary between the recess 210 and the peripheral surface 204 is 11.9 × cos 30 ° = 10.3 mm. Further, when θ _{1 is set} to 20 ° in order to suppress the floating of the recording medium 14, L ₁ = 19.7 mm, L ₂ = 255.9 mm, L ₃ = 6.7 mm, L ₄ = 219.1 mm, θ ₂ = 5 °, D = 5.8 mm, which satisfies the above condition. At this time, the distance from the tip position of the gripper 80 to the boundary between the recess 210 and the peripheral surface 204 is 19.7 × cos 20 ° = 18.5 mm.

Note that when θ ₁ = 20 °, L ₁ is larger than when θ ₁ = 30 °, and the user layout area is reduced, but it is advantageous in that the floating of the recording medium 14 is suppressed. It can be said that there is. In this example, although the case where the surface 204A has one inclination was demonstrated, you may comprise the surface 204A from the several surface from which inclination differs.

  The following pattern is given as a specific example of the landing position evaluation pattern. First, dot rows are formed along the transport direction of the recording medium 14 from ink droplets continuously ejected from nozzles separated by a predetermined number of nozzles in the width direction of the recording medium 14, and a dot row group for one stage is formed. Form. Next, nozzles for ejecting ink are switched to form a similar nozzle array group, and this is repeated a predetermined number of times to eject ink droplets from all nozzles at predetermined intervals along the transport direction of the recording medium 14. A pattern having a plurality of arranged dot rows in the conveyance direction of the recording medium 14 is formed.

  In the landing position evaluation pattern, the dot row group for one stage is composed of dot rows arranged at equal intervals in the width direction of the recording medium 14, and a plurality of dot row groups are shifted in the transport direction of the recording medium 14. It has a lined pattern. The position for each dot row is grasped from the reading result of the landing position evaluation pattern, and the landing position error in the width direction of the recording medium 14 is obtained for each nozzle. When the interval between the dot rows is made larger than the reading pitch, the reading error can be reduced.

  In addition, the landing position evaluation pattern applied to this example should just be what can evaluate the error of a landing position for every nozzle, and it is possible to apply various patterns other than the pattern mentioned above.

  According to the ink jet recording apparatus configured as described above, the portion of the recording medium 14 that has entered the concave portion 210 of the drawing cylinder 44 serves as the landing position evaluation pattern formation area 14B, and the landing position evaluation is performed on the landing position evaluation pattern formation area 14B. By forming the pattern 280, the landing position error in the landing position evaluation pattern 280 can be enlarged, and the accuracy of the evaluation of the landing position error can be improved.

  In this example, the ink jet recording apparatus 10 including the full line type head having a structure in which nozzles are arranged in the width direction of the recording medium 14 over a length corresponding to the entire width of the recording medium 14 has been described as an example. The present invention is also applicable to an ink jet recording apparatus provided with a serial scan type head. In addition, the form in which the recording medium 14 is held and conveyed is not limited to the impression cylinder conveyance method, and can be applied to other methods such as a belt conveyance method.

[First Modification]
Next, a first modification according to the embodiment of the present invention will be described. FIG. 14 is an explanatory view schematically showing the recording medium 14 supported by the drawing cylinder 44 ′ according to the first modification. In the figure, parts that are the same as or similar to those in FIG.

  As shown in FIG. 14, the recess 210 ′ of the drawing cylinder 44 ′ has a surface 204 </ b> A ′ that is substantially parallel to the peripheral surface 204, and a step is provided between the peripheral surface 204 and the surface 204 </ b> A ′. That is, the slow distance with the inkjet head 48 can be enlarged by the step amount α ′, and the landing position evaluation pattern 280 formed on the recording medium 14 (landing position evaluation pattern forming area 14B) supported by the surface 204A ′. The error (see FIG. 11) can be enlarged.

  In such a structure, the nozzle surface 114A (see FIG. 5) of the ink jet head 48 and the landing position evaluation pattern formation area 14B of the recording medium 14 are substantially parallel, so that substantial landing is achieved compared to the embodiment shown in FIG. The position evaluation pattern formation area 14B can be secured more widely.

[Second Modification]
Next, a second modification according to the embodiment of the present invention will be described. FIG. 15 is a partially enlarged view in which the concave portion of the drawing cylinder according to the second modification is enlarged. As shown in the drawing, a suction hole 300 is provided in the claw base 213 to which the tip fixing area 14A (see FIG. 11) of the recording medium 14 is fixed. Further, suction holes 302 are also provided on the surface 204A to which the landing position evaluation pattern forming area 14B of the recording medium 14 is fixed.

  By generating suction pressure in the tip fixing area 14A and the landing position evaluation pattern forming area 14B on the recording medium 14 through the suction holes 300 and 302, these can be reliably fixed, and landing position evaluation can be performed. The accuracy can be improved. Note that various shapes such as a circular shape and an ellipse shape can be applied as the planar shape of the suction holes 300 and 302.

[Third Modification]
FIG. 16 is an explanatory diagram showing a configuration of a third modification example according to the embodiment of the present invention. As shown in the figure, in the third modification, a pressing member 320 that presses the recording medium 14 is added to the configuration shown in FIG. The pressing member 320 has a pressing portion 322 having a shape corresponding to the shape formed by the peripheral surface 204 and the surface 204A of the drawing cylinder 44, and presses the portion located at the boundary between the peripheral surface 204 and the surface 204A of the recording medium 14. The landing position evaluation pattern forming area 14B of the recording medium 14 is pressed against the surface 204A by pressing the portion 322.

  According to this configuration, the landing position evaluation pattern formation area 14B of the recording medium 14 can be brought into close contact with the surface 204A, and the accuracy of the landing position evaluation can be improved.

[Example of application to other devices]
In the above embodiment, application to an inkjet recording apparatus for graphic printing has been described as an example, but the scope of application of the present invention is not limited to this example. For example, a wiring drawing device that draws a wiring pattern of an electronic circuit, a manufacturing device for various devices, a resist printing device that uses a resin liquid as a functional liquid for ejection, a color filter manufacturing device, and a material deposition material. The present invention can be widely applied to inkjet systems that obtain various shapes and patterns using a liquid functional material, such as a fine structure forming apparatus for forming a structure.

[Appendix]
As can be understood from the description of the embodiment described in detail above, the present specification includes disclosure of various technical ideas including the invention described below.

  (Invention 1): A recording head provided with a recording element for forming dots on a recording medium, and the recording head side from a first surface that supports a drawing unit on which a recording image of the recording medium is drawn from the back side And a fixing member that is disposed on the inner side of the first surface so as not to protrude from the first surface and fixes an end of the recording medium, and that the recording head is longer than a distance between the recording head and the first surface. A recording medium holding means having a second surface to which a blank area including an end portion fixed by the fixing member is fixed, a recording medium held by the recording medium holding means, A dot formation position evaluation pattern for evaluating the dot formation position by operating the recording element in the blank area fixed to the second surface and a moving means for relatively moving the recording head is recorded. Image recording apparatus comprising: the drive control means for controlling the driving of sea urchin said recording head, further comprising a.

  According to the present invention, the blank area of the recording medium is fixed on the second surface that is larger than the first surface that supports the drawing area, and the dot formation position evaluation pattern is recorded in the blank area. Therefore, the error of the dot formation position evaluation pattern is relatively enlarged, and it is possible to evaluate the error of the dot formation position with higher accuracy.

  As the fixing member in the present invention, it is possible to apply a sandwiching member that sandwiches the leading end portion of the recording medium between the second surface and sandwiching the leading end portion.

  (Invention 2): In the image recording apparatus described in Invention 1, the recording medium holding means includes a drum-shaped recording medium conveying member having the first surface as an outer peripheral surface.

  In such an aspect, an aspect in which the drawing area of the recording medium is fixed to the outer peripheral surface is preferable. An example of an aspect for fixing the drawing area of the recording medium to the outer peripheral surface is an adsorption fixing method.

  (Invention 3): In the image recording apparatus according to Invention 1 or 2, the recording head can record an image on the recording medium by one relative movement of the recording medium and the recording head, and the recording head. And a movement control means for controlling the movement means so as to relatively move the recording medium and the recording head for all the image recording target areas of the recording medium in the image recording. The drive control means controls the drive of the recording head so that a predetermined image is recorded in an image recording target area of the recording medium in the image recording.

  In such an aspect, an aspect including a full-line recording head in which a plurality of recording elements are arranged over a length corresponding to the entire width of the recording medium is preferable.

  (Invention 4): The image recording apparatus according to any one of Inventions 1 to 3, further comprising reading means for reading the dot formation position evaluation pattern.

  As the reading means in such a mode, a mode in which reading is performed at a reading resolution lower than the recording resolution can be applied.

  (Invention 5): In the image recording apparatus according to Invention 4, the dot forming position is evaluated for each of the recording elements based on the reading result of the reading unit to determine whether or not there is an abnormality in dot formation. It is characterized by comprising a judging means for judging whether or not to perform maintenance of the recording head in accordance with the abnormal dot formation.

  According to this aspect, it is possible to more accurately determine whether there is an abnormality in the nozzle, and it is possible to prevent erroneous nozzle determination as to whether or not to perform maintenance.

  (Invention 6): In the image recording apparatus according to any one of Inventions 1 to 5, the second surface includes an inclined surface inclined inward from the first surface.

  According to this aspect, it is possible to evaluate the dot formation position with higher accuracy without greatly changing the existing form.

  An embodiment in which the angle between the inclined surface and the horizontal surface is 20 ° or more is preferable, and the angle between the inclined surface and the horizontal surface is more preferably 30 ° or more. In addition, the inclined surface may include a plurality of inclined surfaces having different inclinations.

  (Invention 7): In the image recording apparatus according to any one of Inventions 1 to 6, the recording medium holding member has a structure in which a step is provided between the first surface and the second surface. It is characterized by that.

  According to this aspect, it is possible to secure a larger area where the dot position evaluation pattern can be formed.

  It is preferable that the amount of the step is 5 times or more the interval between the recording head and the recording medium supported by the first surface. According to this aspect, the reading resolution of the dot position evaluation pattern can be reduced to about 1/5 of the recording resolution, and the options of the reading device are widened.

(Invention 8): In the image recording apparatus according to any one of Inventions 1 to 7,
A suction holding means for sucking and holding the blank area fixed to the second surface is provided.

  According to this aspect, since the blank area is securely fixed and the floating is prevented, the dot position formation pattern can be formed more accurately.

  In such an embodiment, it is only necessary that at least the area where the dot position formation pattern is formed is fixed in the blank area. Of course, the portion fixed by the fixing member may be further fixed.

  (Invention 9): The image recording apparatus according to any one of Inventions 1 to 8, further comprising a pressing portion having a shape corresponding to a shape formed from the first surface and the second surface, A pressing means is provided for pressing the recording medium held by the recording medium holding means by a pressing portion.

  In this aspect, the recording medium can be brought into close contact with the shape formed from the first surface and the second surface.

  (Invention 10): A drawing portion on which a recording image of the recording medium is drawn is supported from the back side on a first surface facing a recording surface of a recording head provided with a recording element for forming dots on the recording medium, An end portion of the recording medium is fixed by a fixing member disposed inside the first surface so as not to protrude toward the recording head from the first surface, and the recording head and the first surface are fixed. A blank area including an end fixed by the fixing member is fixed to the second surface having a distance between the recording head and the recording head larger than the distance between the recording medium and the recording head held relative to each other. The recording head is driven so as to record a dot formation position evaluation pattern for evaluating the dot formation position by operating the recording element in the blank area fixed on the second surface. To control Image recording method in which the butterflies.

  (Invention 11): A drawing section on which a recording image of the recording medium is drawn is supported from the back side on a first surface facing a recording surface of a recording head provided with a recording element for forming dots on the recording medium, An end portion of the recording medium is fixed by a fixing member disposed inside the first surface so as not to protrude toward the recording head from the first surface, and the recording head and the first surface are fixed. A blank area including an end fixed by the fixing member is fixed to the second surface having a distance between the recording head and the recording head larger than the distance between the recording medium and the recording head held relative to each other. The recording head is driven so as to record a dot formation position evaluation pattern for evaluating the dot formation position by operating the recording element in the blank area fixed on the second surface. Control and shape Is read dot formation position evaluation pattern, reading results to evaluate the dot formation positions for each recording element on the basis of dot formation position evaluation method characterized by the presence or absence of dot formation abnormality is determined.

  (Invention 12): In the dot formation position evaluation method described in Invention 11, it is determined whether or not to perform maintenance of the recording head according to the determined presence or absence of abnormality in dot formation. .

  The maintenance of the recording head may be a recovery process such as cleaning of the recording element or a recovery process of the entire recording head.

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 44 ... Drawing cylinder, 48, 48M, 48K, 48C, 48Y, 100 ... Head, 80 ... Gripper, 82 ... Inline sensor, 108 ... Nozzle, 148 ... Head drive part, 166 ... Inline detection part, 168: determination unit, 172: system controller, 204 ... peripheral surface, 204A ... surface, 213 ... claw base, 300, 302 ... suction hole, 320 ... pressing member

Claims (12)

A recording head provided with a recording element for forming dots on the recording medium;
An end portion of the recording medium is disposed on the inner side of the first surface so as not to protrude toward the recording head side than the first surface that supports the drawing portion on which the recording image of the recording medium is drawn from the back side. And a margin area including an end portion fixed by the fixing member is fixed, the distance between the recording head and the first surface being larger than the distance between the recording head and the first surface. A recording medium holding means having a second surface,
Moving means for relatively moving the recording medium held by the recording medium holding means and the recording head;
Drive control means for controlling the drive of the recording head so as to record a dot formation position evaluation pattern for operating the recording element to evaluate the dot formation position in the margin area fixed on the second surface; ,
An image recording apparatus comprising: The image recording apparatus according to claim 1,
The image recording apparatus according to claim 1, wherein the recording medium holding unit includes a drum-shaped recording medium conveyance member having the first surface as an outer peripheral surface. The image recording apparatus according to claim 1 or 2,
An area on the recording medium on which the recording head can record an image by the relative movement of the recording medium and the recording head once and the recording head are relatively moved once, and the recording medium of the recording medium in the image recording A movement control means for controlling the movement means so as to move the recording medium and the recording head relative to each other for an image recording target area;
The drive control means controls the drive of the recording head so that a predetermined image is recorded in an image recording target area of the recording medium in the image recording. The image recording apparatus according to any one of claims 1 to 3,
An image recording apparatus comprising reading means for reading the dot formation position evaluation pattern. The image recording apparatus according to claim 4,
Based on the reading result of the reading means, the dot formation position is evaluated for each recording element to determine the presence or absence of dot formation abnormality, and the maintenance of the recording head is performed according to the determined dot formation abnormality. An image recording apparatus comprising: a determination unit that determines whether or not to execute. The image recording apparatus according to any one of claims 1 to 5,
The image recording apparatus according to claim 1, wherein the second surface includes an inclined surface inclined inward from the first surface. The image recording apparatus according to any one of claims 1 to 6,
The image recording apparatus, wherein the recording medium holding member has a structure in which a step is provided between the first surface and the second surface. The image recording apparatus according to any one of claims 1 to 7,
An image recording apparatus comprising: suction holding means for sucking and holding the blank area fixed to the second surface. The image recording apparatus according to any one of claims 1 to 8,
A pressing unit that has a pressing portion having a shape corresponding to the shape formed by the first surface and the second surface, and that presses the recording medium held by the recording medium holding unit by the pressing unit; An image recording apparatus comprising the image recording apparatus. A drawing portion on which a recording image of the recording medium is drawn is supported from the back side on a first surface facing a recording surface of a recording head provided with a recording element for forming dots on the recording medium, and the first surface An end portion of the recording medium is fixed by a fixing member disposed on the inner side of the first surface so as not to protrude further toward the recording head side, and is longer than a distance between the recording head and the first surface. A margin area including an end fixed by the fixing member is fixed to the second surface having a large distance from the recording head,
A dot formation position for evaluating the dot formation position by moving the held recording medium and the recording head relatively and operating the recording element in the blank area fixed to the second surface. An image recording method, wherein driving of the recording head is controlled so as to record an evaluation pattern. A drawing portion on which a recording image of the recording medium is drawn is supported from the back side on a first surface facing a recording surface of a recording head provided with a recording element for forming dots on the recording medium, and the first surface An end portion of the recording medium is fixed by a fixing member disposed on the inner side of the first surface so as not to protrude further toward the recording head side, and is longer than a distance between the recording head and the first surface. A margin area including an end fixed by the fixing member is fixed to the second surface having a large distance from the recording head,
A dot formation position for evaluating the dot formation position by moving the held recording medium and the recording head relatively and operating the recording element in the blank area fixed to the second surface. Controlling the drive of the recording head to record the evaluation pattern,
A dot formation position evaluation method comprising: reading the formed dot formation position evaluation pattern, evaluating the dot formation position for each recording element based on the read result, and determining whether there is an abnormality in dot formation. In the dot formation position evaluation method according to claim 11,
A dot formation position evaluation method, wherein whether or not to perform maintenance of the recording head is determined according to the determined presence / absence of dot formation abnormality.

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