JP2018193171A - Detection device, detection method, conveyance device, and inkjet recording device - Google Patents

Abstract

To provide a detection device, a detection method, a conveyance device, and an inkjet recording device which enable detection of expansion and contraction deformation of a medium.SOLUTION: A measurement part 204 for measuring the height of a plurality of positions in a first direction, a calculation part for calculating the length on the first surface of a medium in the first direction, and a determination part for determining the existence of a deformation of the medium is included, the measurement part performs measurement on a range including a non-end part in the first direction with respect to an end part of the medium in the second direction. The calculation part calculates a first calculation value representing a difference or ratio between the first end length which is the length on the first surface of the medium in the first direction and the first reference value with respect to the end part of the medium in the second direction. The determination part determines the deformation of the medium in the first direction from the first calculation value and the first threshold value.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a detection device, a detection method, a conveyance device, and an ink jet recording apparatus, and more particularly to detection of a sheet.

  In image forming apparatuses such as printers and copiers, there is a technique for grasping the size of a medium, the shape of the medium, and the like by using at least one of the length of the medium in the transport direction and the length of the medium in the width direction. Are known.

  Patent Document 1 includes a manual paper feed unit that can notify a user of a mismatch when the size of a medium set in the manual paper feed unit is different from the size of a designated medium. Copiers are listed. Note that the medium in this specification corresponds to the paper in Patent Document 1.

  Patent Document 2 starts recording with an inexpensive and simple configuration so that information can be easily recorded on a different size medium in a page unit while the demand for printing on a medium other than a standard size is increasing. An ink jet recording apparatus capable of managing the page of recording information by knowing the length of the medium has been described.

  The invention described in Patent Document 2 is based on the difference between the detection timing of the leading edge and the detection timing of the trailing edge, by feeding a sheet-like medium in a predetermined direction and detecting passage of the leading edge and trailing edge of the medium. Thus, the length of the medium feeding direction is calculated.

  In the invention described in Patent Document 2, the length of the medium in the conveyance direction is the shortest distance from the leading edge of the medium to the trailing edge of the medium. Note that the medium in this specification corresponds to the recording medium in Patent Document 2. Moreover, the detection in this specification respond | corresponds to the detection in patent document 2. FIG.

  Patent Document 3 describes a transport apparatus that can determine the shape of a medium with high accuracy with a simple configuration. In the transport device described in Patent Document 3, the transported medium is heated and pressurized from the fixing device during printing on one surface, and thus, for example, the medium is stretched and deformed unevenly from a rectangle to a trapezoid. Solves the problem of misalignment.

  In the invention described in Patent Document 3, when the first detection sensor detects the leading edge of the sheet, the width detection sensor detects the positions of both ends in the medium width direction. Further, the trailing edge detection sensor detects the trailing edge position of the medium. The length in the conveyance direction of the medium is obtained from the detection position of the trailing edge detection sensor when the first detection sensor detects the leading edge of the medium. In the invention described in Patent Document 3, the length of the medium in the conveyance direction is the shortest distance from the leading edge of the medium to the trailing edge of the medium.

  Next, the medium is transported, and the rear end portion in the transport direction is detected by the second detection sensor. At that time, the width detection sensor detects the positions of both ends in the width direction of the sheet. The shape of the medium based on the positions of both ends in the width direction when the first detection sensor detects the leading end of the medium and the positions of both ends in the width direction when the second detecting sensor detects the trailing end of the medium. Is calculated. The medium in this specification corresponds to the sheet in Patent Document 3. Moreover, the detection in this specification respond | corresponds to the detection in patent document 3. FIG.

Japanese Patent Laid-Open No. 7-092859 Japanese Patent Laid-Open No. 2-128874 JP 2014-101219 A

  In order to obtain a high-definition image in an ink jet printer, it is necessary to reduce the ink landing variation by reducing the distance between the ejection surface of the liquid ejection head and the medium. For this purpose, the medium must be deformed into a flat state by suction support using suction holes provided on the surface that supports the medium. For example, in the case of a medium in which wood fibers are used as the main raw material, depending on the storage environment of the medium, local expansion and deformation of the medium may occur, and it may be difficult to deform the medium into a flat state. obtain.

  When it is difficult to deform the medium into a flat state, the medium may come into contact with the ejection surface of the inkjet head. If the conveyance of the medium is not suddenly stopped before the contact between the medium and the ejection surface occurs, the ink jet head may be damaged. Therefore, the floating of the medium to be conveyed is measured in advance, and if there is a possibility that the medium and the ejection surface come into contact, the conveyance of the medium is suddenly stopped before the medium and the ejection surface come into contact with each other. It reaches.

  In order to suppress expansion / contraction deformation of the medium, it is necessary to control the environment from the production of the medium to distribution, cutting, and stacking in the paper feeding unit within a certain range, but there are multiple processes. It is difficult to control the environmental humidity within a certain range. Therefore, compared to a general offset printing machine that transports a medium using a nip roller, the inkjet recording apparatus has a problem that jams due to the expansion / contraction change of the medium increase and the downtime of the apparatus increases. Exists.

  The reason why local expansion / contraction deformation occurs in the medium depending on the storage environment of the medium is as follows. The medium in the following description is a medium in which local expansion and deformation can occur due to moisture absorption or dehumidification of paper or the like.

  It is already known that the mechanical properties of the medium are highly dependent on the surrounding humidity environment. In particular, there is a positive correlation between the ambient relative humidity and the moisture content of the medium. Due to the increase in the moisture content of the medium, the wood fibers that are the main raw material of the medium absorb moisture, the medium is stretched, and the Young's modulus of the medium is decreased. This softens the medium. On the other hand, the wood fibers are dried due to a decrease in the moisture content of the medium, the medium shrinks, and the Young's modulus of the medium increases. This hardens the medium.

  In general, paper manufacturers ship their media adjusted to a moisture content that is balanced in an environment where the relative humidity is around 60 percent Rh. Therefore, if the relative humidity of the printing chamber is away from 60 percent Rh, the moisture distribution of the medium becomes uneven, and the medium expands and contracts such as curls, wave edges, and tight edges.

  Note that Rh is an abbreviation for relative humidity, which is an English expression for relative humidity. The printing room represents an example of an environment in which a printing apparatus that uses a medium is arranged.

  In the case of a medium stored in a stacked state, the moisture content of the central part of the medium that does not come into contact with the outside air does not change, and the central part of the medium does not expand or contract. On the other hand, the moisture content of the four sides of the medium in contact with the outside air changes depending on the change in the relative humidity around the medium, and the four sides of the medium undergo expansion and contraction.

  Therefore, due to a change in humidity around the medium, characteristic deformation of the medium called a wave edge and a tight edge occurs.

  In the case of flatly deforming one medium that has been stretched and deformed in this way, it is necessary to match the length of the central portion where the stretch deformation has not occurred and the length of the end portion where the stretch deformation has occurred. For example, when expansion / contraction deformation of the medium occurs along the medium conveyance direction, even if a tensile load or a compression load is applied in a direction parallel to the conveyance direction, the medium is thin and the medium is easily seated. The medium is wrinkled due to bending. The same applies when the medium is stretched and deformed along the medium width direction.

  Therefore, when expansion / contraction deformation occurs at the end of the medium, it is difficult to deform the medium flat. The end portion of the medium can include both an end portion in the medium transport direction and an end portion in the medium width direction.

  The length of the medium measured in the invention described in Patent Document 1 is grasped by measuring the shortest distance between the leading edge of the medium and the trailing edge of the medium in the medium conveyance direction. It is difficult to determine whether the medium is stretched or deformed using the shortest distance between the leading edge of the medium and the trailing edge of the medium in the medium conveyance direction.

  The invention described in Patent Document 1 is intended to detect a mismatch between the size of an actual medium and the size of a designated medium, and Patent Document 1 discloses an invention related to detection of expansion / contraction deformation of the medium. Not done.

  In the invention described in Patent Document 2, as in the invention described in Patent Document 1, the shortest distance between the leading edge of the medium and the trailing edge of the medium in the medium conveyance direction is measured as the length of the medium to be measured. It is difficult to detect expansion / contraction deformation of the medium. The invention described in Patent Document 2 detects the length of a medium for the purpose of managing recorded information, and Patent Document 2 does not disclose an invention related to detection of expansion / contraction deformation of the medium.

  In the invention described in Patent Document 3, the shape of the medium is calculated by detecting the position of the end in the width direction of the medium, the front end position of the medium, and the rear end position of the medium. The length in the transport direction is the shortest distance between the front end and the rear end. Therefore, it is difficult to detect expansion / contraction deformation of the medium.

  The invention described in Patent Document 3 is intended to calculate the shape of the medium, and Patent Document 3 does not disclose an invention relating to detection of expansion / contraction deformation of the medium.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a detection device, a detection method, a transport device, and an ink jet recording apparatus capable of detecting expansion / contraction deformation of a medium.

  In order to achieve the above object, the following invention aspects are provided.

  The detection device according to the first aspect uses a measurement unit that measures the heights of a plurality of positions in the first direction on the first surface of the sheet-like medium, and a medium in the first direction using the measurement results of the measurement unit. Whether or not the deformation of the medium is in an allowable range based on the length on the first surface of the medium in the first direction calculated using the calculation unit A determination unit that determines whether or not the measurement unit has a first direction in a range including at least a non-end part in the first direction with respect to the end of the medium in the second direction orthogonal to the first direction. The height of a plurality of positions is measured, and the computing unit corresponds to the range measured using the measuring unit for the end of the medium in the second direction, and the length on the first surface of the medium in the first direction. The first end length is calculated and the difference between the first end length and the first reference value or Whether or not the deformation of the medium in the first direction is within an allowable range based on a comparison result between the first calculation value and a predetermined first threshold value. It is a detection device that determines whether or not.

  According to the first aspect, it is possible to detect expansion / contraction deformation of a medium such as a wave edge and a tight edge based on the length on the first surface of the medium at the edge of the medium.

  An example of the medium is paper.

  The length on the first surface of the medium is the length along the first surface of the medium in the first direction. The length on the first surface of the medium can be equal to or longer than the shortest distance from the front end to the rear end of the medium in a medium in which expansion / contraction deformation has occurred.

  The end portion is a range determined from the viewpoint of easy expansion and contraction, and means within a predetermined distance range from the end of the medium. The non-end portion is a region other than the end portion, and means a range exceeding a predetermined distance from the end of the medium.

  According to a second aspect, in the detection device according to the first aspect, the measurement unit measures the heights of a plurality of positions in the first direction with respect to the entire length of the medium in the first direction at the end of the medium in the second direction. The computing unit may calculate the first end length corresponding to the total length of the medium in the first direction for the end of the medium in the second direction.

  According to the second aspect, it is possible to increase the difference between the first calculated value and the first threshold value as compared with the case where a part of the medium is measured, and the first end length of the medium is calculated. The accuracy of calculation is improved.

  According to a third aspect, in the detection device according to the first aspect or the second aspect, the calculation unit performs line integration with the measurement range of the measurement unit as an integration range for the measurement result obtained from the measurement unit, and the first end length It is good also as a structure which calculates.

  According to the third aspect, it is possible to calculate the first end length using the measurement result of the height of the medium.

  The fourth aspect is the detection device according to any one of the first aspect to the third aspect, wherein the measurement unit covers at least a non-end portion of the medium in the second direction including a non-end portion in the first direction. Measuring the height of a plurality of positions in the first direction, the computing unit corresponding to the range measured using the measuring unit for the non-end portion of the medium in the second direction, It is good also as a structure which calculates the 1st non-end part length which is the length on a 1st surface, and calculates using a 1st non-end part length as a 1st reference value.

  According to the fourth aspect, the first reference value suitable for the state of expansion / contraction deformation of the medium by using the first non-end length calculated using the measurement result of the non-end portion of the medium as the first reference value. Can be used.

  According to a fifth aspect, in the detection device according to the fourth aspect, with respect to the non-end portion of the medium in the second direction, the measurement unit sets the heights of the plurality of positions in the first direction for the entire length of the medium in the first direction. The measurement unit may calculate the first non-end length corresponding to the total length of the medium in the first direction for the non-end portion of the medium in the second direction.

  According to the 5th aspect, the precision of the calculation at the time of calculating the 1st non-end part length of a medium improves.

  According to a sixth aspect, in the detection device according to the fourth aspect or the fifth aspect, the calculation unit performs line integration with the measurement range of the measurement unit as an integration range for the measurement result obtained from the measurement unit. It is good also as composition which computes a general manager.

  According to the sixth aspect, it is possible to calculate the first non-end length using the measurement result of the medium height.

  According to a seventh aspect, in the detection device according to any one of the first aspect to the sixth aspect, the measurement unit may include a non-contact type measurement device or a contact type measurement device.

  Examples of the non-contact type measuring device include a laser displacement meter and a stereoscopic camera. An example of a contact-type measuring instrument is a step gauge.

  An eighth aspect is the detection device according to the seventh aspect, wherein the detection device according to the seventh aspect includes a first relative movement unit that relatively moves the non-contact type measurement device or the contact type measurement device and the medium in the first direction. Also good.

  According to the 8th aspect, the measurement by the relative movement of a medium and a measuring device is attained about a 1st direction.

  In the eighth aspect, the medium may be fixed and the measuring instrument may be moved in the first direction. In addition, the measuring device may be fixed and the medium may be moved in the first direction. Furthermore, both the medium and the measuring device may be moved relative to each other in the first direction.

  According to a ninth aspect, in the detection device according to the seventh aspect or the eighth aspect, a non-contact type measurement device or a second relative movement unit that relatively moves the contact type measurement device and the medium in the second direction. It is good also as a structure provided.

  According to the ninth aspect, measurement by relative movement between the medium and the measuring instrument in the second direction is possible.

  In the ninth aspect, the measuring device may be moved in the second direction while fixing the medium. Further, the medium may be moved in the second direction with the measuring instrument fixed. Further, both the medium and the measuring device may be moved relative to each other in the second direction.

  According to a tenth aspect, in the detection device according to the eighth aspect or the ninth aspect, the measurement unit uses the timing at which the measurement value corresponding to the thickness of the medium changes as a reference timing, and the relative movement speed of the medium and the measurement unit, and The height measurement range may be determined using the elapsed period from the reference timing.

  According to the tenth aspect, in the measurement of the height of the medium using the measurement unit, the measurement range can be determined using the measurement parameter of the measurement unit.

  According to an eleventh aspect, in the detection device according to any one of the first aspect to the tenth aspect, the measurement unit targets a range including at least a non-end portion in the second direction with respect to the end portion of the medium in the first direction. Measuring the height of a plurality of positions in the second direction, and the computing unit corresponds to the range measured using the measuring unit for the end of the medium in the first direction, and the first of the medium in the second direction The second end length, which is the length on the surface, is calculated, and a calculation is performed to calculate a second calculated value representing a difference or ratio between the second end length and the second reference value. A configuration may be adopted in which it is determined whether the deformation of the medium in the second direction is within an allowable range based on a comparison result between the calculated value and a predetermined second threshold value.

  According to the eleventh aspect, it is possible to detect the presence or absence of expansion / contraction deformation of the medium in both the first direction and the second direction.

  According to a twelfth aspect, in the detection device according to the eleventh aspect, the measurement unit measures the heights of a plurality of positions in the second direction with respect to the entire length of the medium in the second direction at the end of the medium in the first direction. The computing unit may calculate a second end length corresponding to the total length of the medium in the second direction for the end of the medium in the first direction.

  According to the twelfth aspect, the calculation accuracy when calculating the second end length of the medium is improved.

  According to a thirteenth aspect, in the detection device according to the eleventh aspect or the twelfth aspect, the measurement unit includes the end of the medium in the second direction and the end of the medium in the second direction with respect to the non-end of the medium in the first direction. Measuring the range including the portion, the computing unit calculates the second non-end length, which is the length on the first surface of the medium in the second direction, for the non-end portion of the medium in the first direction, and It is good also as a structure which calculates by making 2nd non-end part length into a 2nd reference value.

  According to the thirteenth aspect, the second reference value suitable for the state of expansion / contraction deformation of the medium is obtained by using the second non-end length calculated using the measurement result of the non-end portion of the medium as the second reference value. Can be used.

  According to a fourteenth aspect, in the detection device according to the thirteenth aspect, the measurement unit measures the heights of the plurality of positions in the second direction with respect to the entire length of the medium in the second direction with respect to the non-end portion of the medium in the first direction. The measurement unit may calculate the second non-end length corresponding to the total length of the medium in the second direction for the non-end portion of the medium in the first direction.

  According to the fourteenth aspect, the accuracy of calculation when calculating the second non-end length of the medium is improved.

  According to a fifteenth aspect, in the detection device according to any one of the first aspect to the fourteenth aspect, the end of the medium is within a range of 50 millimeters from the end of the medium, and the non-end of the medium is the end of the medium. It is good also as a structure which is the range which exceeds 50 millimeters from.

  According to the fifteenth aspect, it is possible to detect expansion / contraction deformation of the medium within 50 mm from the edge of the medium.

  The detection method according to the sixteenth aspect includes a measuring step of measuring the heights of a plurality of positions in the first direction on the first surface of the sheet-like medium, and a medium in the first direction using the measurement results of the measuring step. Whether or not the deformation of the medium is within an allowable range based on the calculation step of calculating the length on the first surface of the medium and the length on the first surface of the medium in the first direction calculated in the calculation step. A determination step, and the measurement step includes a plurality of media in the first direction for a range including at least a non-end portion in the first direction with respect to the end of the medium in the second direction orthogonal to the first direction. The height of the position is measured, and the calculation step is a length on the first surface of the medium in the first direction corresponding to the range measured in the measurement step for the end of the medium in the second direction. The end length is calculated and the first end length and the first length A calculation is performed to calculate a first calculation value that represents a difference or ratio from the reference value, and the determination step is performed based on a comparison result between the first calculation value and a predetermined first threshold value. This is a detection method for determining whether or not the deformation is within an allowable range.

  According to the sixteenth aspect, the same effect as in the first aspect can be obtained.

  In the sixteenth aspect, matters similar to the matters specified in the second aspect to the fifteenth aspect can be appropriately combined. In that case, the component responsible for the process or function specified in the detection apparatus can be grasped as the component of the detection method responsible for the process or function corresponding thereto.

  A transport device according to a seventeenth aspect includes a transport unit that transports a sheet-like medium, a measurement unit that measures the height of a plurality of positions in the first direction, and a measurement result of the measurement unit on the first surface of the medium. And calculating the length on the first surface of the medium in the first direction, based on the length on the first surface of the medium in the first direction calculated using the calculation unit, A determination unit that determines whether or not the deformation is in an allowable range, and the measurement unit includes at least a non-end portion in the first direction with respect to the end portion of the medium in the second direction orthogonal to the first direction. The height of a plurality of positions in the first direction is measured, and the computing unit corresponds to the range measured using the measuring unit for the end of the medium in the second direction. A first end length which is a length on the first surface of the first end, and the first end A calculation for calculating a first calculation value representing a difference or ratio between the length and the first reference value is performed, and the determination unit determines whether the first calculation value is based on a comparison result between the first calculation value and a predetermined first threshold value. This is a transport device that determines whether or not the deformation of the medium in the direction is within an allowable range.

  According to the seventeenth aspect, the same effect as in the first aspect can be obtained.

  In the seventeenth aspect, the same matters as those specified in the second to fifteenth aspects can be appropriately combined. In that case, the component responsible for the process or function specified in the detection device can be grasped as the component of the transport device responsible for the process or function corresponding thereto.

  An inkjet recording apparatus according to an eighteenth aspect measures the heights of a plurality of positions in a first direction with respect to an inkjet head that ejects ink onto a sheet-like medium, a conveyance unit that conveys the medium, and a first surface of the medium. A measurement unit that calculates the length on the first surface of the medium in the first direction using the measurement result of the measurement unit, and the first of the medium in the first direction calculated using the calculation unit A determination unit that determines whether the deformation of the medium is within an allowable range based on the length on the surface, and the measurement unit is configured to measure the end of the medium in the second direction orthogonal to the first direction. The height of a plurality of positions in the first direction is measured for a range including at least the non-end portion in the first direction, and the calculation unit is measured using the measurement unit for the end of the medium in the second direction. In the first direction, corresponding to the The first end length, which is the length on the first surface of the medium to be calculated, is calculated, and the first calculated value representing the difference or ratio between the first end length and the first reference value is calculated and determined. The unit is an ink jet recording apparatus that determines whether the deformation of the medium in the first direction is within an allowable range based on a comparison result between the first calculated value and a predetermined first threshold value.

  According to the eighteenth aspect, the same effect as in the first aspect can be obtained.

  In the eighteenth aspect, matters similar to the matters specified in the second aspect to the fifteenth aspect can be appropriately combined. In that case, the component responsible for the process or function specified in the detection apparatus can be grasped as the component of the ink jet recording apparatus responsible for the process or function corresponding to this.

  A nineteenth aspect is the ink jet recording apparatus according to the eighteenth aspect, further comprising a medium thickness information acquisition unit that acquires information on the thickness of the medium, and the conveyance unit applies adsorption pressure to the medium by applying an adsorption pressure to adsorb and support the medium. The adsorption pressure applying unit may be configured to control the magnitude of the adsorption pressure applied to the medium based on the medium thickness information acquired using the medium thickness information acquiring unit.

  According to the nineteenth aspect, the adsorption pressure applied to the medium is controlled according to the thickness of the medium. Thereby, the conveyance abnormality of the medium resulting from lack of adsorption pressure is suppressed.

  In the nineteenth aspect, when the thickness of the medium in which expansion / contraction deformation exceeding the allowable range is detected is equal to or less than a predetermined thickness, the adsorption pressure applied to the medium is dynamically controlled to reduce the expansion / contraction deformation of the medium. It is possible to avoid abnormal conveyance of the medium.

  According to a twentieth aspect, in the ink jet recording apparatus according to the eighteenth aspect or the nineteenth aspect, a medium supply unit that supplies a medium to the transport unit may be provided, and the measurement unit may be included in the medium supply unit.

  According to the twentieth aspect, it is possible to detect the presence or absence of expansion / contraction deformation of the medium in the medium supply unit. Thereby, it is possible to remove the medium in which expansion and contraction has occurred before supply.

  In a twenty-first aspect, in the inkjet recording apparatus according to any one of the eighteenth aspect to the twentieth aspect, when the determination unit determines that the deformation of the medium exceeds the allowable range, the medium is discharged from the conveyance unit. It is good also as a structure provided with the discharge part.

  According to the twenty-first aspect, it is possible to remove a medium in which expansion / contraction deformation has occurred.

  According to the present invention, it is possible to detect expansion / contraction deformation of a medium such as a wave edge and a tight edge based on the length on the first surface of the medium at the edge of the medium.

FIG. 1 is an overall configuration diagram of an ink jet recording apparatus. FIG. 2 is a block diagram showing a schematic configuration of the control system. FIG. 3 is a block diagram of the detection apparatus shown in FIG. FIG. 4 is a configuration diagram of the detection device showing a configuration example of the detection device shown in FIG. FIG. 5 is a perspective view showing an example of a wave edge. FIG. 6 is a perspective view showing an example of a tight edge. FIG. 7 is a plan view of a sheet showing an end portion of the sheet and a non-end portion of the sheet in detection of expansion / contraction deformation of the sheet. FIG. 8 is a plan view of a sheet showing the coordinates of the sheet and the measurement position of the sheet in the detection of expansion / contraction deformation of the sheet. FIG. 9 is a diagram illustrating an example of measurement results obtained from the measurement unit. FIG. 10 is a partially enlarged view of FIG. FIG. 11 is a diagram illustrating an example of a measurement result obtained from the measurement unit when a tight edge is generated. FIG. 12 is a flowchart showing a flow of a procedure for detecting expansion / contraction deformation of a sheet. FIG. 13 is a flowchart showing a flow of a procedure of a paper feeding method in the ink jet recording apparatus shown in FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, the same components are denoted by the same reference numerals, and redundant description is omitted.

[Explanation of terms]
Parallel in this specification includes substantial parallel that intersects but can obtain the same effect as parallel. In addition, the orthogonality includes a substantial orthogonality that intersects at an angle of less than 90 degrees or exceeds 90 degrees, but can obtain the same effect as the case of intersecting at 90 degrees.

  The upper direction in this specification represents a direction opposite to the direction of gravity. The same applies to the upper part and the upper part. Below is the gravity direction. The same applies to the lower part and the lower part.

  The same thing in this specification includes the substantially same thing which can obtain the same effect, although it is different.

  In the present specification, ink and liquid can be read interchangeably.

  The ejection, droplet ejection, image formation, and image recording in this specification can be read interchangeably.

  In the present specification, the paper transport direction and the medium transport direction can be interchanged. Further, the sheet width direction and the medium width direction can be interchanged with each other. The paper width direction is a direction orthogonal to the paper transport direction. The medium width direction is a direction orthogonal to the medium conveyance direction.

[Description of Inkjet Recording Device]
<Overall configuration>
FIG. 1 is an overall configuration diagram of an ink jet recording apparatus. An ink jet recording apparatus 10 shown in FIG. 1 is an ink jet recording apparatus that draws an image on a sheet of paper S using an ink jet method. Paper S can be applied as the paper S. The paper S may be called a medium, a print medium, or the like. The sheet S is an aspect of a sheet-like medium.

  The ink jet recording apparatus 10 mainly includes a paper feeding unit 12, a detection device 13, a processing liquid application unit 14, a processing liquid drying processing unit 16, a drawing unit 18, an ink drying processing unit 20, and a paper discharge unit 24. Hereinafter, each part will be described in detail.

<Paper Feeder>
The sheet feeding unit 12 includes a sheet feeding table 30, a sheet feeding roller pair 34, a feeder board 36, a front pad 38, and a sheet feeding drum 40. The feeder board 36 includes a retainer 36A and a guide roller 36B. The paper feed unit 12 includes a soccer device (not shown).

  The retainer 36 </ b> A and the guide roller 36 </ b> B are disposed on the transport surface on which the paper S of the feeder board 36 is transported. The front pad 38 is disposed between the feeder board 36 and the paper feed drum 40.

  The paper feed drum 40 has a cylindrical shape whose longitudinal direction is parallel to the rotation shaft 40B. The paper supply drum 40 has a length that exceeds the total length of the paper S in the longitudinal direction. The direction of the rotation shaft 40B of the paper supply drum 40 is a direction that penetrates the paper surface of FIG.

  The drum has a cylindrical shape, and is a transport member that transports the paper S along the cylindrical outer peripheral surface by holding at least a part of the paper S and rotating it about the central axis of the cylindrical shape. .

  The paper feed drum 40 includes a gripper 40A. The gripper 40A includes a plurality of claws, a claw base, and a gripper shaft. A plurality of claws, claw bases, and gripper shafts are not shown.

  The plurality of claws of the gripper 40 </ b> A are arranged along a direction parallel to the rotation shaft 40 </ b> B of the paper feed drum 40. The base ends of the plurality of claws are swingably supported by the gripper shaft. The arrangement interval of the plurality of claws and the length of the area where the plurality of claws are arranged are determined according to the size of the paper S.

  The claw base is a member whose longitudinal direction is a direction parallel to the rotation shaft 40 </ b> B of the paper feed drum 40. With respect to the longitudinal direction of the paper supply drum 40, the length of the claw base is set to be equal to or longer than the length of the region where the plurality of claws are arranged. The claw base is disposed at a position facing the tip portions of the plurality of claws.

  The sheet feeding unit 12 feeds the sheets S stacked on the sheet feeding table 30 to the processing liquid applying unit 14 one by one. The sheets S stacked on the sheet feed table 30 are pulled up one by one in order from the top using a soccer device (not shown) and fed to the pair of sheet feed rollers 34.

  The paper S fed to the paper feed roller pair 34 is placed on the feeder board 36 and conveyed using the feeder board 36. The sheet S conveyed using the feeder board 36 is pressed against the conveying surface of the feeder board 36 using the retainer 36A and the guide roller 36B, and the unevenness is corrected.

  The sheet S conveyed using the feeder board 36 is corrected in inclination due to the leading end abutting against the front pad 38. The paper S conveyed using the feeder board 36 is delivered to the paper supply drum 40.

  The leading edge of the paper S delivered to the paper supply drum 40 is gripped using the gripper 40 </ b> A of the paper supply drum 40. Due to the rotation of the paper supply drum 40, the paper S is conveyed along the outer peripheral surface of the paper supply drum 40. The paper S conveyed using the paper supply drum 40 is delivered to the processing liquid application unit 14. The paper feed unit 12 is an example of a medium supply unit.

<Detection device>
The detection device 13 is disposed at a position where the paper S on the paper feed tray 30 or the paper S immediately after being separated from the paper feed tray 30 one by one can be detected. The detection device 13 can be provided in the paper feeding unit 12. The detection device 13 acquires at least one of the height information of the paper S in the transport direction of the paper S and the height information of the paper S in the width direction of the paper S at a constant cycle. Details of the detection device 13 will be described later.

  Hereinafter, the transport direction of the paper S is referred to as a paper transport direction. Further, the width direction of the paper S is referred to as a paper width direction.

<Processing liquid application part>
The treatment liquid application unit 14 includes a treatment liquid drum 42 and a treatment liquid application device 44. The treatment liquid drum 42 includes a gripper 42A. A configuration similar to that of the gripper 40A of the paper feed drum 40 can be applied to the gripper 42A.

  The processing liquid drum 42 shown in FIG. 1 has a circumferential length that is twice that of the paper supply drum 40. The treatment liquid drum 42 is provided with two grippers 42A. The arrangement positions of the two grippers 42 </ b> A are positions shifted by a half circumference on the outer peripheral surface 42 </ b> C of the processing liquid drum 42.

  The treatment liquid drum 42 has a configuration in which the paper S is fixed to the outer peripheral surface 42 </ b> C that supports the paper S. As an example of a configuration in which the sheet S is fixed to the outer peripheral surface 42C of the processing liquid drum 42, there is a configuration in which a plurality of suction holes are provided in the outer peripheral surface 42C of the processing liquid drum 42 and negative pressure is generated in the plurality of suction holes.

  Except for the above, the processing liquid drum 42 can have the same configuration as the paper feed drum 40. Reference numeral 42 </ b> B is a rotation shaft of the treatment liquid drum 42.

  A roller coating method is applied to the treatment liquid applying device 44 shown in FIG. The processing liquid application device 44 shown in FIG. 1 includes a processing liquid tank, a metering roller, and an application roller. In addition, illustration of a process liquid tank, a measurement roller, and an application | coating roller is abbreviate | omitted.

  Note that the configuration of the treatment liquid application device 44 illustrated in FIG. 1 is merely an example, and the treatment liquid application device 44 may be applied by other methods such as coating using a blade, ejection using an inkjet method, or spraying using a spray method. The method may be applied.

  The sheet S is transported along the outer peripheral surface 42 </ b> C of the processing liquid drum 42 due to the rotation of the processing liquid drum 42 in the state where the leading edge of the sheet S is gripped using the gripper 42 </ b> A. The processing liquid is applied to the sheet S conveyed along the outer peripheral surface 42 </ b> C of the processing liquid drum 42 using the processing liquid applying device 44. The sheet S to which the processing liquid is applied is sent to the processing liquid drying processing unit 16.

  The treatment liquid applied to the paper S has a function of aggregating the color material in the ink discharged onto the paper S by the drawing unit 18 at the subsequent stage or a function of insolubilizing the color material of the ink. Due to the treatment liquid being applied to the paper S and causing ink to be ejected, even if a general-purpose paper is used, high-quality image formation can be performed without causing landing interference or the like.

  The sheet S to which the processing liquid is applied using the processing liquid application unit 14 is delivered to the processing liquid drying processing unit 16.

<Processing liquid drying processing section>
The processing liquid drying processing unit 16 includes a processing liquid drying processing drum 46, a paper transport guide 48, and a processing liquid drying processing unit 50. The processing liquid drying processing drum 46 includes a gripper 46A. A configuration similar to that of the gripper 40A of the paper supply drum 40 can be applied to the gripper 46A.

  The processing liquid drying processing drum 46 shown in FIG. 1 has a circumferential length twice that of the paper supply drum 40. The treatment liquid drying treatment drum 46 is provided with two grippers 46 </ b> A in the same manner as the treatment liquid drum 42. The same arrangement as that of the treatment liquid drum 42 can be applied to the arrangement of the two grippers 46A.

  A configuration similar to that of the paper supply drum 40 can be applied to the configuration other than the above of the processing liquid drying processing drum 46. Reference numeral 46B denotes a rotation shaft of the treatment liquid drying treatment drum 46.

  The paper transport guide 48 is disposed at a position facing the outer peripheral surface 46 </ b> C of the processing liquid drying processing drum 46. The paper transport guide 48 is disposed below the processing liquid drying processing drum 46.

  The processing liquid drying processing unit 50 is disposed inside the processing liquid drying processing drum 46. The processing liquid drying processing unit 50 includes a blower that blows air toward the outside of the processing liquid drying processing drum 46 and a heating unit that heats the wind. For convenience of illustration, reference numerals of the blower unit and the heating unit are omitted.

  The leading edge of the sheet S delivered from the processing liquid application unit 14 to the processing liquid drying processing unit 16 is gripped using a gripper 46 </ b> A of the processing liquid drying processing drum 46.

  The sheet S is supported by a sheet conveyance guide 48 on the surface opposite to the surface on which the processing liquid is applied. When supported using the paper transport guide 48, the paper S is in a state where the surface coated with the processing liquid faces the outer peripheral surface 46 </ b> C of the processing liquid drying processing drum 46.

  The sheet S is conveyed along the outer peripheral surface 46 </ b> C of the processing liquid drying processing drum 46 due to the rotation of the processing liquid drying processing drum 46.

  The paper S that is transported using the processing liquid drying processing drum 46 and supported by the paper transport guide 48 is subjected to a drying process by blowing air heated from the processing liquid drying processing unit 50. Applied.

  Due to the drying process performed on the paper S, the solvent component in the processing liquid applied to the paper S is removed, and a processing liquid layer is formed on the surface of the paper S to which the processing liquid is applied. The paper S that has been dried using the processing liquid drying processing unit 16 is delivered to the drawing unit 18.

<Drawing part>
The drawing unit 18 includes a drawing drum 52, a sheet pressing roller 54, a liquid discharge head 56C, a liquid discharge head 56M, a liquid discharge head 56Y, a liquid discharge head 56K, and an inline sensor 58.

  The drawing drum 52 includes a gripper 52A. The gripper 52 </ b> A is disposed inside a recess provided on the outer peripheral surface 52 </ b> C of the drawing drum 52. A configuration similar to that of the gripper 40A of the paper feed drum 40 can be applied to the configuration other than the arrangement of the gripper 52A.

  As with the processing liquid drum 42, the drawing drum 52 has two grippers 52A. The same arrangement as that of the treatment liquid drum 42 can be applied to the arrangement of the two grippers 52A.

  The drawing drum 52 has suction holes on the outer peripheral surface 52C that supports the paper S. The suction holes are arranged in a medium support area for sucking and supporting the paper S. Illustration of the suction holes and the medium support area is omitted.

  A configuration similar to that of the paper feed drum 40 can be applied to the configuration of the drawing drum 52 other than the above. Reference numeral 52B denotes a rotation axis of the drawing drum 52.

  The sheet pressing roller 54 has a cylindrical shape. The longitudinal direction of the paper pressing roller 54 is a direction parallel to the rotation shaft 52B of the drawing drum 52 and the paper width direction. The sheet pressing roller 54 has a length equal to or longer than the entire length of the sheet S in the sheet width direction in the longitudinal direction.

  The paper pressing roller 54 is located downstream of the delivery position of the paper S with respect to the paper transport direction in the drawing drum 52, and is located upstream of the liquid ejection head 56C.

  The liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K include a nozzle unit that discharges ink using an inkjet method. The illustration of the nozzle portion is omitted. The nozzle portion includes a nozzle opening formed on the liquid discharge surface. The nozzle portion may include a pressure chamber communicating with the nozzle opening, and a nozzle communication channel connecting the nozzle opening and the pressure chamber.

  In FIG. 1, alphabets attached to the reference numerals of the liquid discharge heads represent ink colors. C represents cyan. M represents magenta. Y represents yellow. K represents black.

  The liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K are arranged at a position above the drawing drum 52. The liquid ejection head 56C, the liquid ejection head 56M, the liquid ejection head 56Y, and the liquid ejection head 56K are arranged along the paper transport direction from the upstream side in the paper transport direction, from the liquid discharge head 56C, the liquid discharge head 56M, and the liquid discharge head. 56Y and the liquid discharge head 56K are arranged in this order.

  The in-line sensor 58 is disposed at a position downstream of the liquid ejection head 56K in the paper transport direction. The inline sensor 58 includes an image sensor, a peripheral circuit of the image sensor, and a light source.

  As the imaging device, a solid-state imaging device such as a CCD image sensor or a CMOS image sensor can be applied. In addition, illustration of an image sensor, a peripheral circuit of the image sensor, and a light source is omitted. CCD is an abbreviation for Charge Coupled Device. CMOS is an abbreviation for Complementary Metal-Oxide Semiconductor.

  The peripheral circuit of the image sensor includes a processing circuit for an output signal of the image sensor. Examples of the processing circuit include a filter circuit, an amplifier circuit, or a waveform shaping circuit that removes noise components from the output signal of the image sensor. Note that illustration of a filter circuit, an amplifier circuit, or a waveform shaping circuit is omitted.

  The light source is disposed at a position where the reading object of the in-line sensor 58 can be irradiated with illumination light. An LED, a lamp, or the like can be applied as the light source. LED is an abbreviation for light emitting diode.

  The leading edge of the sheet S delivered from the processing liquid drying processing unit 16 to the drawing unit 18 is gripped by using the gripper 52 </ b> A of the drawing drum 52. The sheet S whose leading end is gripped using the gripper 52 </ b> A of the drawing drum 52 is conveyed along the outer peripheral surface 52 </ b> C of the drawing drum 52 due to the rotation of the drawing drum 52.

  When the sheet S passes under the sheet pressing roller 54, it is pressed against the outer peripheral surface 52 </ b> C of the drawing drum 52. The sheet S that has passed under the sheet pressing roller 54 is directly under the liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K, and the liquid discharge head 56C, the liquid discharge head 56M, and the liquid discharge head. Images are formed using color ink ejected from each of 56Y and liquid ejection head 56K.

  The sheet S on which an image is formed using the liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K is read using the inline sensor 58 in the reading area of the inline sensor 58. .

  The read information of the inline sensor 58 is transmitted to a system controller (not shown in FIG. 1). The system controller is shown in FIG. The read information of the in-line sensor 58 can be applied to ejection abnormality detection of the liquid ejection head 56C, the liquid ejection head 56M, the liquid ejection head 56Y, and the liquid ejection head 56K.

  The paper S on which an image has been read using the inline sensor 58 is delivered from the drawing unit 18 to the ink drying processing unit 20.

<Ink drying processing section>
The ink drying processing unit 20 includes a chain gripper 64, an ink drying processing unit 68, and a guide plate 72. The chain gripper 64 includes a first sprocket 64A, a second sprocket 64B, a chain 64C, and a plurality of grippers 64D.

  The chain gripper 64 has a structure in which a pair of endless chains 64C are wound around a pair of first sprockets 64A and a second sprocket 64B. FIG. 1 shows only one of the pair of first sprockets 64A, the pair of second sprockets 64B, and the pair of chains 64C.

  The chain gripper 64 has a structure in which a plurality of grippers 64D are disposed between a pair of chains 64C. The chain gripper 64 has a structure in which a plurality of grippers 64D are arranged at a plurality of positions in the paper conveyance direction. FIG. 1 shows only one gripper 64D among the plurality of grippers 64D arranged between the pair of chains 64C.

  The chain gripper 64 shown in FIG. 1 includes a horizontal conveyance area for conveying the paper S along the horizontal direction and an inclined conveyance area for conveying the paper S obliquely upward.

  The ink drying processing unit 68 is arranged at a position above the transport path of the paper S in the chain gripper 64. A configuration example of the ink drying processing unit 68 includes a configuration including a heat source such as a halogen heater or an infrared heater. Another configuration example of the ink drying processing unit 68 includes a configuration including a fan that blows air heated by using a heat source onto the paper S. The ink drying processing unit 68 may include a heat source and a fan.

  Although detailed illustration of the guide plate 72 is omitted, a plate-like member is applied to the guide plate 72. The guide plate 72 has a length that exceeds the total length of the paper S in a direction orthogonal to the paper conveyance direction in the chain gripper 64.

  The guide plate 72 is disposed along the conveyance path in the horizontal conveyance region of the paper S using the chain gripper 64. The guide plate 72 is disposed at a position below the transport path of the paper S using the chain gripper 64. The guide plate 72 has a length corresponding to the length of the processing region of the ink drying processing unit 68 in the paper transport direction in the chain gripper 64.

  The length corresponding to the length of the processing region of the ink drying processing unit 68 is the length of the guide plate 72 that can support the paper S on which the guide plate 72 is used during the processing of the ink drying processing unit 68. .

  For example, with respect to the paper transport direction, a mode in which the length of the processing region of the ink drying processing unit 68 and the length of the guide plate 72 are the same can be cited. The guide plate 72 may have a function of sucking and supporting the paper S.

  Instead of the guide plate 72, a belt having suction holes for sucking the paper S may be provided. The belt may be moved in synchronization with the chain gripper 64. The moving direction of the belt is a direction parallel to the traveling direction of the chain gripper 64.

  The leading edge of the sheet S delivered from the drawing unit 18 to the ink drying processing unit 20 is gripped using the gripper 64D. By causing at least one of the first sprocket 64A and the second sprocket 64B to rotate clockwise in FIG. 1 and causing the chain 64C to travel, the sheet S is conveyed along the travel path of the chain 64C. The

  When the paper S passes through the processing area of the ink drying processing unit 68, the ink drying processing is performed on the paper S using the ink drying processing unit 68. The paper S that has been subjected to the ink drying process using the ink drying processing unit 68 is transported using the chain gripper 64 and sent to the paper discharge unit 24.

  The chain gripper 64 shown in FIG. 1 conveys the sheet S in the diagonally upper left direction in FIG. 1 at a position downstream of the ink drying processing unit 68 in the sheet conveyance direction. A guide plate 73 is disposed on the conveyance path in the inclined conveyance area where the sheet S is conveyed in the diagonally upper left direction in FIG.

  As the guide plate 73, a member similar to the guide plate 72 can be applied. Here, description of the structure and function of the guide plate 73 is omitted.

<Output section>
The paper discharge unit 24 includes a paper discharge stand 76. A chain gripper 64 is applied to transport the paper S in the paper discharge unit 24. The paper discharge tray 76 is disposed at a position below the conveyance path of the paper S using the chain gripper 64. The paper discharge tray 76 can include a lifting mechanism (not shown). The paper discharge tray 76 can be raised and lowered according to the increase / decrease of the stacked sheets S to keep the height of the uppermost sheet S constant.

  The paper discharge unit 24 collects the paper S that has undergone a series of image formation processes. When the paper S reaches the position of the paper discharge tray 76, the gripper 64D releases the grip of the paper S. The paper S is stacked on the paper discharge tray 76.

  In FIG. 1, the inkjet recording apparatus 10 including the processing liquid application unit 14 and the processing liquid drying processing unit 16 is illustrated, but an aspect in which the processing liquid application unit 14 and the processing liquid drying processing unit 16 are omitted is also possible. is there.

  In FIG. 1, the chain gripper 64 is illustrated as a configuration for transporting the paper S after drawing. However, other transport modes such as belt transport or transport drum transport are applied to the configuration for transporting the paper S after drawing. May be.

[Description of liquid discharge head]
<Overall configuration>
The liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K illustrated in FIG. 1 are line-type heads in which nozzle portions are formed over the entire length of the sheet S in the sheet width direction. Applied.

  In the following description, the liquid ejection head 56 is a general term for the liquid ejection head 56C, the liquid ejection head 56M, the liquid ejection head 56Y, and the liquid ejection head 56K illustrated in FIG. 1, or the liquid ejection head 56C and the liquid ejection head 56M. Represents any one of the liquid ejection head 56Y and the liquid ejection head 56K. The liquid discharge head 56 is an example of an inkjet head.

  The liquid discharge head 56 can employ a structure in which a plurality of head modules are connected in the paper width direction. The plurality of head modules constituting the liquid discharge head 56 can be applied with the same structure. Further, the head module can function as a liquid discharge head alone. The head module is not shown.

  The head module may include an ink supply unit including an ink supply chamber and an ink circulation chamber on the upper surface side opposite to the liquid ejection surface. The ink supply chamber is connected to the ink tank via a supply-side individual flow path.

  The ink circulation chamber is connected to the recovery tank via the recovery side individual flow path. In addition, illustration of an ink supply chamber, an ink supply unit, an ink tank, an ink circulation chamber, a collection side individual flow path, and a collection tank is omitted.

  In the short direction of the head module, the head module may be fixed with the main body portion sandwiched between the fixing members from both sides. In addition, illustration of a main-body part and a fixing member is abbreviate | omitted.

  In this specification, the short direction of the head module can be read as the short direction of the liquid discharge head 56. In the present specification, the short direction of the head module and the short direction of the liquid discharge head can be read as the paper transport direction.

  A plurality of nozzle openings are formed on the liquid ejection surface. A two-dimensional arrangement may be applied to the plurality of nozzle openings.

  The head module has an end surface on the long side along a long side direction having a first angle inclination with respect to a direction orthogonal to the medium conveyance direction, and a short side direction having a second angle inclination with respect to the medium conveyance direction. It is good also as a parallelogram plane shape which has the end surface of the short side along A.

  In the head module, a plurality of nozzle openings may be arranged in a matrix in the row direction along the long side direction and the column direction along the short side direction. A plurality of nozzle openings may be arranged in a matrix along the row direction along the direction orthogonal to the medium conveyance direction and the column direction obliquely intersecting with the direction orthogonal to the medium conveyance direction.

  The matrix arrangement of nozzle openings refers to a direction orthogonal to the medium conveyance direction in which a plurality of nozzle openings are projected in a direction orthogonal to the medium conveyance direction and the plurality of nozzle openings are arranged along a direction orthogonal to the medium conveyance direction. In this projection nozzle row, the nozzle openings are arranged at uniform intervals between the nozzle openings.

  The head module may employ a structure including an ink supply path, an individual supply path, a pressure chamber, a nozzle communication path, and a circulation individual flow path. In the head module, a vibration plate and a piezoelectric element are disposed on a flow path structure in which an ink supply path, an individual supply path, a pressure chamber, a nozzle communication path, a circulation individual flow path, and a circulation common flow path are formed. A structure can be adopted.

  The ink supply path, individual supply path, pressure chamber, nozzle communication path, circulation individual flow path, flow path structure, diaphragm, and piezoelectric element are not shown.

  The piezoelectric element may be disposed on the diaphragm via an adhesive layer. The piezoelectric element may have a laminated structure of a lower electrode, a piezoelectric layer, and an upper electrode. The lower electrode may be shared with the diaphragm. The upper electrode may be an individual electrode patterned corresponding to the shape of each pressure chamber.

  The piezoelectric element may have a structure in which a piezoelectric layer is formed integrally with a plurality of nozzle portions, individual electrodes are formed corresponding to each nozzle portion, and an active region is formed for each nozzle portion. .

  Ink is supplied from the ink supply path to the pressure chamber via the individual supply path. When a driving voltage is applied to the piezoelectric element, the piezoelectric element is deformed and the volume of the pressure chamber changes. In accordance with a pressure change accompanying a change in the volume of the pressure chamber, ink is ejected from the nozzle opening via the nozzle communication path.

  According to the dot arrangement data generated from the input image data, the drive of the piezoelectric element corresponding to each nozzle opening is controlled, and ink is ejected from the nozzle opening.

  While the paper S is transported in the medium transport direction at a constant speed, the ink ejection timing from each nozzle opening is controlled in accordance with the transport speed of the paper S, and a desired image is formed on the paper S.

  The pressure chamber may have a substantially square planar shape. The pressure chamber may be provided with an outlet to the nozzle opening at one of the corners on the diagonal of the square, and an individual supply path as an inlet for the supply ink on the other.

  The planar shape of the pressure chamber is not limited to a square. The planar shape of the pressure chamber may have various forms such as a rhombus, a quadrangle such as a rectangle, a pentagon, a hexagon and other polygons, a circle, and an ellipse.

  A circulation outlet is formed in the nozzle part including the nozzle opening and the nozzle communication path. The nozzle portion communicates with the circulation individual flow path via the circulation outlet. Of the ink in the nozzle communication path and the ink in the nozzle opening, ink that is not used for droplet ejection is collected into the circulation common flow path via the circulation individual flow path.

  The circulation common flow path is connected to the ink circulation chamber. The ink is collected through the circulation individual flow path to the circulation common flow path, and thickening of the ink in the vicinity of the nozzle opening at the time of non-droplet ejection is prevented.

  A thermal system that includes a heater inside the pressure chamber as a pressure generating element instead of a piezoelectric element, supplies a drive voltage to the heater to generate heat, and uses the film boiling phenomenon to eject ink inside the pressure chamber from the nozzle opening May be applied.

<Description of control system>
FIG. 2 is a block diagram showing a schematic configuration of the control system. As shown in FIG. 2, the inkjet recording apparatus 10 includes a system controller 100. The system controller 100 includes a CPU 100A, a ROM 100B, and a RAM 100C.

The ROM 100B and the RAM 100C illustrated in FIG. 2 may be disposed outside the CPU. CPU is an abbreviation for Central Processing Unit. ROM is an abbreviation for Read Only Memory. RAM is an abbreviation for Random Access Memory.

  The system controller 100 functions as an overall control unit that comprehensively controls each unit of the inkjet recording apparatus 10. Further, the system controller 100 functions as an arithmetic unit that performs various arithmetic processes. The system controller 100 may control each unit of the inkjet recording apparatus 10 by executing a program.

  Furthermore, the system controller 100 functions as a memory controller that controls reading and writing of data in memories such as the ROM 100B and the RAM 100C.

  The inkjet recording apparatus 10 includes a communication unit 102, an image memory 104, a conveyance control unit 110, a paper feed control unit 112, a processing liquid application control unit 114, a processing liquid drying control unit 116, a drawing control unit 118, an ink drying control unit 120, A paper discharge control unit 124 is provided.

  The communication unit 102 includes a communication interface (not shown). The communication unit 102 can transmit and receive data to and from the host computer 103 connected to the communication interface.

  The image memory 104 functions as a temporary storage unit for various data including image data. The image memory 104 reads and writes data through the system controller 100. Image data captured from the host computer 103 via the communication unit 102 is temporarily stored in the image memory 104.

  The conveyance control unit 110 controls the operation of the conveyance unit 11 for the paper S in the inkjet recording apparatus 10. The transport unit 11 illustrated in FIG. 2 includes the processing liquid drum 42, the processing liquid drying processing drum 46, the drawing drum 52, and the chain gripper 64 illustrated in FIG.

  The paper feed control unit 112 illustrated in FIG. 2 controls the operation of the paper feed unit 12 in accordance with a command from the system controller 100. The paper feed control unit 112 controls the paper S supply start operation, the paper S supply stop operation, and the like.

  The processing liquid application control unit 114 controls the operation of the processing liquid application unit 14 according to a command from the system controller 100. The treatment liquid application control unit 114 controls the application amount and application timing of the process liquid.

  The processing liquid drying control unit 116 controls the operation of the processing liquid drying processing unit 16 in accordance with a command from the system controller 100. The treatment liquid drying control unit 116 controls the drying temperature, the flow rate of the dry gas, the injection timing of the dry gas, and the like.

  The drawing control unit 118 controls the operation of the drawing unit 18 in response to a command from the system controller 100. The drawing control unit 118 controls ink ejection of the liquid ejection head 56C, the liquid ejection head 56M, the liquid ejection head 56Y, and the liquid ejection head 56K illustrated in FIG.

  The drawing control unit 118 shown in FIG. 2 includes an image processing unit (not shown). The image processing unit forms dot data from the input image data. The image processing unit includes a color separation processing unit, a color conversion processing unit, a correction processing unit, and a halftone processing unit (not shown).

  The color separation processing unit performs color separation processing on the input image data. For example, when the input image data is expressed in RGB, the input image data is decomposed into data for each of R, G, and B colors. Here, R represents red. G represents green. B represents blue.

  The color conversion processing unit converts the image data for each color separated into R, G, and B into C, M, Y, and K corresponding to the ink colors. Here, C represents cyan. M represents magenta. Y represents yellow. K represents black.

  The correction processing unit performs correction processing on the image data for each color converted into C, M, Y, and K. Examples of the correction processing include gamma correction processing, density unevenness correction processing, abnormal recording element correction processing, and the like.

  For example, the halftone processing unit converts the image data represented by a multi-gradation number such as 0 to 255 into dot data represented by a binary or multi-value of three or more values less than the number of gradations of the input image data. Convert.

  A predetermined halftone processing rule is applied to the halftone processing using the halftone processing unit. Examples of the halftone processing rule include a dither method and an error diffusion method. The halftone processing rule may be changed according to the image recording conditions, the content of the image data, and the like.

  The drawing control unit 118 includes a waveform generation unit, a waveform storage unit, and a drive circuit (not shown). The waveform generator generates a drive voltage waveform. The waveform storage unit stores the waveform of the drive voltage. The drive circuit generates a drive voltage having a drive waveform corresponding to the dot data. The drive circuit supplies a drive voltage to the liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K shown in FIG.

  That is, the discharge timing and ink discharge amount of each pixel position are determined based on the dot data generated through the processing using the image processing unit, and the discharge timing and ink of each pixel position are determined based on the dot data. A control signal that determines the drive voltage corresponding to the discharge amount and the discharge timing of each pixel is generated.

  The drive voltage and the control signal are supplied to the liquid discharge head 56C, the liquid discharge head 56M, the liquid discharge head 56Y, and the liquid discharge head 56K. Based on the drive voltage and the control signal, dots are recorded on the paper S using the ink ejected from the liquid ejection head 56C, the liquid ejection head 56M, the liquid ejection head 56Y, and the liquid ejection head 56K.

  The ink drying control unit 120 illustrated in FIG. 2 controls the operation of the ink drying processing unit 20 in accordance with a command from the system controller 100. The ink drying control unit 120 controls the drying gas temperature, the flow rate of the drying gas, or the ejection timing of the drying gas.

  The paper discharge control unit 124 controls the operation of the paper discharge unit 24 in accordance with a command from the system controller 100. The paper discharge control unit 124 controls the operation of the lifting mechanism according to the increase / decrease of the paper S when the paper discharge tray 76 shown in FIG.

  The ink jet recording apparatus 10 illustrated in FIG. 2 includes a detection device 13 and a modified paper discharge control unit 126. The detection device 13 detects whether or not the expansion and contraction deformation leading to the jam has occurred in the paper S. The detection device 13 transmits the detection result to the modified sheet discharge control unit 126 via the system controller 100.

  The deformed sheet discharge control unit 126 uses the deformed sheet discharge unit 26 to discharge the sheet S on which the expansion / contraction deformation from the conveyance path of the sheet S to the jam occurs based on the detection result of the detection device 13. The sheet S is the sheet S shown in FIG. The same applies to the following description. The modified paper discharge unit 26 is an example of a discharge unit.

  The ink jet recording apparatus 10 illustrated in FIG. 2 includes a thickness information acquisition unit 128. The thickness information acquisition unit 128 acquires the thickness information of the paper S including the thickness of the paper S. The thickness information acquisition unit 128 transmits the thickness information of the paper S to the transport control unit 110 via the system controller 100.

  The thickness information acquisition unit 128 may acquire the thickness information of the paper S input by the operator. The thickness information acquisition unit 128 may acquire the thickness information of the paper S by reading the thickness information of the paper S from an information storage body attached to a stocker or the like of the paper S. The thickness information acquisition unit 128 is an example of a medium thickness information acquisition unit.

  The conveyance control unit 110 controls the suction pressure applied to the paper S according to the thickness of the paper S using a suction pressure application unit (not shown). That is, a relatively large suction pressure is applied to the relatively thick paper S. A relatively small suction pressure is applied to the sheet S having a relatively small thickness.

  The conveyance control unit 110 may read the set value of the suction pressure applied to the paper S from the table representing the relationship between the thickness of the paper S and the suction pressure applied to the paper S using the thickness of the paper S as a parameter. Good. The suction pressure applied to the paper S here includes the suction pressure of the paper S in the drawing drum 52 of FIG.

  The ink jet recording apparatus 10 illustrated in FIG. 2 includes an operation unit 130, a display unit 132, a parameter storage unit 134, and a program storage unit 136.

  The operation unit 130 includes operation members such as operation buttons, a keyboard, and a touch panel. The operation unit 130 may include a plurality of types of operation members. The illustration of the operation member is omitted.

  Information input via the operation unit 130 is sent to the system controller 100. The system controller 100 executes various processes in accordance with information sent from the operation unit 130.

  The display unit 132 includes a display device such as a liquid crystal panel and a display driver. In FIG. 2, illustration of the display device and the display driver is omitted. In response to a command from the system controller 100, the display unit 132 causes the display device to display various information such as various device setting information and abnormality information.

  The parameter storage unit 134 stores various parameters used in the inkjet recording apparatus 10. Various parameters stored in the parameter storage unit 134 are read out via the system controller 100 and set in each unit of the apparatus.

  The program storage unit 136 stores a program used for each unit of the inkjet recording apparatus 10. Various programs stored in the program storage unit 136 are read out via the system controller 100 and executed in each unit of the apparatus.

  In FIG. 2, each part is listed for each function. Each part shown in FIG. 2 can be integrated, separated, combined, or omitted as appropriate. The same applies to the block diagram of the detection device 13 shown in FIG.

[Detailed Description of Detection Device]
<Overall configuration>
FIG. 3 is a block diagram of the detection apparatus shown in FIG. 3 includes a control unit 200, a communication unit 202, a measurement unit 204, a first movement unit 206, a second movement unit 208, a calculation unit 210, a determination unit 212, and a storage unit 214. .

  The control unit 200 performs overall control of each unit of the detection device 13. The control unit 200 shown in FIG. 3 can share part or all of the system controller 100 shown in FIG.

  The communication unit 202 transmits a detection result of detection of expansion / contraction deformation of the paper S to the system controller 100 illustrated in FIG. 2 based on the control of the control unit 200. A configuration similar to that of the communication unit 102 illustrated in FIG. 2 can be applied to the communication unit 202 illustrated in FIG. 3.

  The measurement unit 204 illustrated in FIG. 3 acquires at least one of the height information of the paper S in the paper conveyance direction and the height information of the paper S in the paper width direction based on the control of the control unit 200. The measuring unit 204 may include a non-contact type measuring device such as a laser displacement meter and a stereoscopic camera that captures a stereoscopic image.

  The non-contact type measuring device may be a measuring device using light other than laser light. The non-contact type measuring device may be a measuring device using ultrasonic waves. The measuring unit 204 may include a contact-type measuring device such as a step meter. Details of the height information of the sheet S will be described later.

  The first moving unit 206 relatively moves the paper S and the measuring instrument in the paper transport direction based on the command signal transmitted from the control unit 200. The first moving unit 206 may move the measuring device with respect to the paper S whose position is fixed. The first moving unit 206 may move the paper S with respect to the measuring instrument whose position is fixed. The first moving unit 206 may move both the paper S and the measuring device.

  The second moving unit 208 relatively moves the paper S and the measuring device in the paper width direction based on the command signal transmitted from the control unit 200. The second moving unit 208 may move the measuring device with respect to the paper S whose position is fixed. The second moving unit 208 may move the paper S with respect to the measuring instrument whose position is fixed. The second moving unit 208 may move both the paper S and the measuring device.

  The calculation unit 210 calculates the length of the paper S based on the height information of the paper S measured using the measurement unit 204. The height information of the paper S includes at least one of the height information of the paper S in the paper transport direction and the height information of the paper S in the paper width direction.

  The arithmetic unit 210 calculates the length of the paper S in the paper transport direction when acquiring the height information of the paper S in the paper transport direction. When the calculation unit 210 acquires the height information of the paper S in the paper width direction, the calculation unit 210 calculates the length of the paper S in the paper width direction.

  When the calculation unit 210 acquires the height information of the paper S in the paper conveyance direction and the height information of the paper S in the paper width direction, the arithmetic unit 210 acquires the length of the paper S in the paper conveyance direction and Calculate the length. Details of the calculation in the calculation unit 210 will be described later.

  The length of the paper S in this embodiment is a length along the first surface of the paper S. The first surface of the paper S is illustrated with reference numeral SA in FIG. The length of the paper S may be a length along the second surface of the paper S, which is the surface opposite to the first surface of the paper S.

  The shortest distance from the front end to the rear end of the paper S in the paper transport direction and the shortest distance between both ends in the paper width direction are not included in the concept of the length of the paper S calculated in the present embodiment.

  Based on the length of the paper S calculated using the calculation unit 210, the determination unit 212 determines whether or not the paper S has undergone expansion / contraction deformation that causes a jam. The determination result of the determination unit 212 is stored in the storage unit 214.

  When the expansion / contraction deformation leading to a jam has occurred in the paper S to be fed, the control unit 200 allows an allowable range for the paper S to be fed through the communication unit 202 and the system controller 100 illustrated in FIG. 2 is transmitted to the deformed sheet discharge control unit 126 shown in FIG.

  The deformed sheet discharge control unit 126 illustrated in FIG. 2 uses the deformed sheet discharge unit 26 to discharge the sheet S that has undergone expansion / contraction deformation from the conveyance path of the sheet S to the jam.

  The hardware structure of the various processing units shown in FIGS. 2 and 3 is the following various processors. Various processors include a CPU, a PLD, and an ASIC. As an example of the processing unit, the various processing units illustrated in FIG. 2 and FIG. 3 are substantially responsible for processing, but the term “processing unit” may not be used in the name. A term such as a control unit may also be included in the concept of various processing units.

  Examples of the various processing units illustrated in FIGS. 2 and 3 include a conveyance control unit 110, a paper feed control unit 112, and a drawing control unit 118. In addition, the control part includes what is described as a processing unit using English notation. Processors include those written as processor using English notation.

  The CPU is a general-purpose processor that executes software and functions as various processing units. Software can be read as a program. The PLD is a processor whose circuit configuration can be changed after manufacture. An example of PLD is FPGA. PLD is an abbreviation for Programmable Logic Device. FPGA is an abbreviation for Field Programmable Gate Array.

The ASIC is a processor or a dedicated electric circuit having a circuit configuration specially designed to execute a specific process. ASIC is Application Specific
It is an abbreviation for Integrated Circuit.

  One processing unit may be composed of one of the various processors described above. One processing unit may be configured using two or more processors of the same type, or two or more processors of different types. Examples of two or more processors of the same type include a plurality of FPGAs. An example of two or more processors of different types is a combination of a CPU and an FPGA.

  A plurality of processing units may be configured using one processor. As an example of configuring a plurality of processing units using one processor, an aspect in which one processor is configured using a combination of one or more CPUs and software, and one processor functions as a plurality of processing units. Can be mentioned. Specific examples include a server and a computer such as a client.

  As another example in which a plurality of processing units are configured by a single processor, there is an aspect in which a processor that realizes the functions of the entire system including a plurality of processing units with a single IC chip is used. A specific example is a system on chip. System-on-chip includes those described as System On Chip or SoC using English notation. IC is an abbreviation for Integrated Circuit.

  As described above, the various processing units illustrated in FIGS. 2 and 3 are configured using one or more of the various processors described above as a hardware structure.

  Furthermore, the hardware structure of the various processors described above is more specifically an electric circuit in which circuit elements such as semiconductor elements are combined. In addition, the electric circuit includes what is described as circuit using English notation.

  Specific examples of the various storage units illustrated in FIGS. 2 and 3 include a memory, a storage element, and a storage device. Examples of the program storage unit 136 shown in FIGS. 2 and 3 include a storage device in which various programs are stored.

<Configuration example of detection device>
FIG. 4 is a configuration diagram of the detection device showing a configuration example of the detection device shown in FIG. An arrow line denoted by reference numeral X in FIG. 4 indicates the paper width direction. Further, an arrow line indicated with a reference symbol Y indicates a sheet conveyance direction.

  The detection device 13 illustrated in FIG. 4 includes a carriage 240 and a width direction guide 242. The carriage 240 is mounted with at least a measuring instrument provided in the measuring unit 204. The width direction guide 242 supports the carriage 240 that moves along the sheet width direction using a motor (not shown). The carriage 240, the width direction guide 242, and the motor (not shown) are components of the first moving unit 206 shown in FIG. The first moving unit is an example of a first relative moving unit.

  The detection device 13 includes a first transport direction guide 260, a second transport direction guide 262, a first support portion 264, and a second support portion 266. The first transport direction guide 260 supports the carriage 240 that moves along the direction parallel to the paper transport direction via the first support portion 264.

  The second transport direction guide 262 supports the carriage 240 that moves along the direction parallel to the paper transport direction via the second support portion 266. The first support portion 264 supports one end of the width direction guide 242. The second support portion 266 supports the other end of the width direction guide 242.

  At least one of the first support portion 264 and the second support portion 266 moves in the medium transport direction using a motor (not shown).

  The first transport direction guide 260, the second transport direction guide 262, the first support portion 264, the second support portion 266, and a motor (not shown) are components of the second moving portion 208 shown in FIG.

  The carriage 240 and the width direction guide 242 illustrated in FIG. 4 move the measurement unit 204 mounted on the carriage 240 along the sheet width direction. The first transport direction guide 260, the second transport direction guide 262, the first support unit 264, and the second support unit 266 move the measurement unit 204 mounted on the carriage 240 along the sheet transport direction.

  In this way, by moving the measurement unit 204 mounted on the carriage 240 in the paper width direction and the paper conveyance direction, the measurement unit 204 is at a height at an arbitrary position on the first surface SA of the fixed paper S. Information can be obtained.

  Although not shown, when the paper S is moved with respect to the fixed measuring unit 204, the paper S can be moved by using a two-dimensional moving stage that moves the paper S in the paper width direction and the paper transport direction. It only has to be supported. The stage in this mode is a component of the first moving unit 206 and the second moving unit 208 shown in FIG. The second moving unit is an example of a second relative moving unit.

  Alternatively, the measurement unit 204 may be moved using the first moving unit 206 shown in FIG. 3 and the sheet S may be moved using the second moving unit 208. Similarly, the sheet S may be moved using the first moving unit 206 and the measuring unit 204 may be moved using the second moving unit 208.

  For the movement of the paper S, a one-dimensional movement stage can be applied. A movement mechanism that moves the carriage 240 can be applied to the movement of the measurement unit 204.

  When detecting the sheet S using the detection device 13 shown in FIG. 4, an arbitrary side of the sheet S is conveyed by using a posture regulating member such as a guide (not shown) in the sheet conveyance direction and the sheet width direction. It is preferable to regulate the posture of the paper S so as to be parallel to the direction or the paper width direction.

  On the other hand, even if the posture regulating member for regulating the posture of the paper S is not provided and the posture of the paper S is inclined with respect to the paper transport direction or the paper width direction, the detection device 13 shown in FIG. It is possible to measure the paper S by using it. For example, when measuring the sheet S inclined obliquely with respect to the sheet conveying direction, the height of the sheet S is measured along the oblique direction with respect to the side of the sheet S in the direction parallel to the sheet conveying direction. Is possible.

  The detection method of the paper S shown in this embodiment is based on the difference or ratio between the length of the paper S at the end of the paper S and the length of the paper S at the non-end of the paper S. And the tight edge is detected, the length of the sheet S at the end of the sheet S and the sheet at the non-end of the sheet S are measured even when measured in an oblique direction with respect to an arbitrary side of the sheet S. The length of S is considered to change with a similar tendency. The difference or the effect on the ratio is negligible.

  However, when measuring the edge of the paper S, the measurement range may be determined so that all measurement positions belong to the edge of the paper S. In other words, when a measurement range in which all measurement positions belong to the edge of the paper S is determined, any one side of the paper S may be inclined with respect to the paper transport direction or the paper width direction. The same applies to the measurement of the non-edge portion of the paper S. The case where the sheet S is skewed when the sheet S is moved and measured is the same as the case where the fixed sheet S is measured.

  That is, in the detection method of expansion / contraction deformation of the paper S shown in the present embodiment, when any one side of the paper S is parallel to the paper conveyance direction or the paper width direction, and any one side of the paper S is the paper conveyance direction. The present invention can be applied to both cases in which the head is inclined with respect to the paper width direction.

<Explanation of expansion and contraction of paper>
Next, expansion / contraction deformation of the paper S will be described. FIG. 5 is a perspective view showing an example of a wave edge. FIG. 6 is a perspective view showing an example of a tight edge.

  The wave edge shown in FIG. 5 is a state in which the four sides SB of the paper S are deformed into a wave shape. The wave edge occurs when the four sides SB of the paper S are expanded as the ambient humidity increases. Reference symbol SC indicates four corners of the paper S. The symbol SD represents the central portion of the paper S.

  The tight edge shown in FIG. 6 is a state in which the four corners SC of the paper S are raised above the central portion SD of the paper S. A tight edge occurs when the four sides SB of the paper S contract as the ambient humidity of the paper S decreases. Note that the tight edge may cause the central portion SD of the paper S to rise above the four corners SC of the paper S.

  The detection device 13 shown in the present embodiment determines whether or not expansion / contraction deformation leading to a jam has occurred, such as the wave edge of the paper S shown in FIG. 5 and the tight edge of the paper S shown in FIG. . The expansion and contraction deformation leading to the jam is difficult to correct even by using the correction mechanism of the paper S provided in the paper conveyance path such as suction support using suction holes provided in the outer peripheral surface 52C of the drawing drum 52 shown in FIG. If it is a stretchable deformation and is transported while the deformation is maintained, a jam may occur. Hereinafter, detection of expansion / contraction deformation leading to a jam will be described in detail.

<Explanation of paper deformation detection>
FIG. 7 is a plan view of a sheet showing an end portion of the sheet and a non-end portion of the sheet in detection of expansion / contraction deformation of the sheet. The detection device 13 shown in the present embodiment calculates the length of the paper S at the non-end portion 300 of the paper S and the length of the paper S at the end of the paper S shown in FIG. When a predetermined threshold value is exceeded, it is determined that the paper S has undergone extreme deformation due to jamming.

  The length of the paper S may be calculated in the paper transport direction and the paper width direction, and the length of the paper S may be calculated in either the paper transport direction or the paper width direction. . When detecting expansion / contraction deformation of the paper S based on the length of the paper S in the paper conveyance direction or the paper width direction, the flow of the paper S may be considered. For example, the expansion / contraction deformation of the paper S may be detected based on the length of the paper S in the direction orthogonal to the flow of the paper S where the paper S is likely to undergo expansion / contraction deformation.

  When calculating the length of the paper S in the paper transport direction, the end of the paper S is at least one of the one end 302 of the paper S in the paper width direction and the other end 304 of the paper S in the paper width direction. On the other hand.

  When calculating the length of the paper S in the paper width direction, the end of the paper S is at least one of the leading end 306 of the paper S in the paper transport direction and the rear end 308 of the paper S in the paper transport direction. is there. One end portion 302, the other end portion 304, the leading end portion 306, and the rear end portion 308 of the sheet S are all within 50 mm from the four sides SB of the sheet S.

  As shown in FIG. 7, the end range in the paper conveyance direction and the end range in the paper width direction may have different sizes. FIG. 7 shows a sheet S in which the end range in the sheet width direction is larger than the end range in the sheet transport direction.

  As described above, the length of the paper S in the paper transport direction is the length along the first surface SA of the paper S in the paper transport direction. The length of the paper S in the paper width direction is the length along the first surface SA of the paper S in the paper width direction.

  When determining whether or not the paper S has undergone stretching deformation leading to a jam in the paper transport direction, the length along the first surface SA of the paper S in the paper transport direction is the first of the medium in the first direction. This corresponds to the length on the surface and the length of the first end.

  In the paper width direction, when it is determined whether the paper S has undergone expansion / contraction deformation leading to a jam, the length along the first surface SA of the paper S in the paper width direction is the first of the medium in the first direction. This corresponds to the length on the surface and the length of the first end.

  The difference between the length of the paper S at the non-end portion 300 and the length of the paper S at the end portion may be calculated by subtracting the length of the paper S at the non-end portion 300 from the length of the paper S at the end portion. The absolute value of the value obtained by subtracting the length of the paper S at the non-end portion 300 from the length of the paper S at the edge may be used.

  Instead of the difference between the length of the paper S at the non-end portion 300 and the length of the paper S at the end portion, a ratio between the length of the paper S at the non-end portion 300 and the length of the paper S at the end portion may be applied. The ratio between the length of the paper S at the non-end portion 300 and the length of the paper S at the end portion may be calculated by dividing the length of the paper S at the end portion by the length of the paper S at the non-end portion 300. Alternatively, the length of the sheet S at the non-end portion 300 may be calculated by dividing by the length of the sheet S at the end portion.

  When the wave edge shown in FIG. 5 occurs and when the tight edge shown in FIG. 6 occurs, the length of the sheet S at the non-end portion 300 and the length of the sheet S at the end portion The size relationship is different.

  As will be described in detail later, when a wave edge occurs in the paper S, the length of the paper S at the non-end portion 300 is less than the length of the paper S at the end portion. On the other hand, when a tight edge occurs in the paper S, the length of the paper S at the non-end portion 300 is longer than the length of the paper S at the end portion.

  Therefore, the difference or ratio between the length of the paper S at the non-end portion 300 and the length of the paper S at the end portion is determined by detecting the wave edge of the paper S, the tight edge of the paper S, or both. It is determined appropriately depending on whether it is detected.

  A specific example of the expansion / contraction deformation detection of the paper S will be described with reference to FIGS. FIG. 8 is a plan view of a sheet showing the coordinates of the sheet and the measurement position of the sheet in the detection of expansion / contraction deformation of the sheet. FIG. 9 is a diagram illustrating an example of measurement results obtained from the measurement unit. FIG. 10 is a partially enlarged view of FIG.

  Hereinafter, a sheet for determining whether or not the sheet S is subject to expansion / contraction deformation leading to a jam based on the length of the sheet S at the end portion and the length of the sheet S at the non-end portion 300 in the sheet conveyance direction. A specific example of S deformation detection will be shown.

One of the four corners SC of the paper S is set as the origin, the paper width direction is set as the x-axis direction, and the paper transport direction is set as the y-axis direction. In the example shown in FIG. 8, the corner SC ₁ in the upper left of the sheet S as the origin O, a direction toward the positive direction of the x-axis direction from the left in FIG. 8 to the right, opposite the positive direction of the y-axis direction in the sheet conveying direction The direction is as follows. Further, the thickness direction of the paper S is defined as the z-axis direction. The positive direction of the z-axis direction is a direction that penetrates the paper surface of FIG. 8 from the back surface to the front surface. Note that the origin and the coordinate axis may be set outside the paper S or inside the paper S.

Then, for any position x ₁ in the sheet width direction of the end portion 302, to measure the height za _i of the sheet S of a plurality of positions y _i along the sheet conveyance direction. The height za _i is illustrated in FIG. If the number of measurement positions is n, i is an integer of 0 or more and n or less. Note that n is determined according to the measurement position of the height za _i of the paper S and the type of expansion / contraction deformation of the paper S among n ₁ and n ₂ shown in FIG. 9 and n ₃ shown in FIG. .

A broken line indicated by reference numeral 320 in FIG. 8 is a line connecting a position y _{i at} which the height za _i is measured at a position x ₁ in the sheet width direction. In the measurement of the height za _i , a laser displacement meter is applied as a measuring instrument of the measuring unit 204 shown in FIG.

In the measurement of the heights za _i of the sheets S at a plurality of positions y _i along the sheet conveyance direction at the position x ₁ in the sheet width direction, first, the measurement unit 204 shown in FIG. 4 is moved to x ₁ . Next, measurement values are acquired from the measurement unit 204 at a constant cycle while the measurement unit 204 is moved at a constant speed along the paper conveyance direction.

The leading edge SE of the paper S is detected using the detection of a step corresponding to the thickness of the paper S as a trigger. The y-axis of the coordinate of the tip SE of the sheet S and _{y 0.}

  The movement distance δ of the measurement unit 204 for each measurement cycle is expressed by the following equation 1 using the speed v of the measurement unit 204 in the paper conveyance direction and the measurement cycle T.

δ = v × T Equation 1
The unit of the movement distance δ of the measurement unit 204 for each measurement cycle is millimeter. The unit of the speed v of the measuring unit 204 in the paper transport direction is millimeter per second. The unit of the measurement period T is second. The measurement unit 204 can specify the measurement position using the speed v of the measurement unit 204.

When the heights za _i of the sheets S at a plurality of positions y _i along the sheet conveyance direction are measured for the entire length of the sheet S in the sheet conveyance direction, the trailing edge of the sheet S is detected from the timing when the leading edge SE of the sheet S is detected. Measurement may be performed for a period until the timing when SF is detected.

It is possible to detect the trailing edge SF of the paper S with the detection of a step corresponding to the thickness of the paper S as a trigger. A coordinate in the y-axis direction corresponding to the rear end SF of the paper S is _{defined as yn1} . A coordinate y _n1 of the rear end SF of the paper S in the y-axis direction is illustrated in FIG. The _{y n} shown in FIG. 8, includes _{y n2, y n3} shown in _{y n1, y n2,} and 11 shown in FIG.

the position y _i of the y-axis direction, the relationship between za _i of the height of the sheet S at the position y _i of the y-axis direction shown in FIG. Y ₀ , y ₁ , y ₂ , y ₃ , y _i−1 , y _i , y _{i + 1} , and y _n1 shown in FIG. 9 are measurement positions of the height of the sheet S at the edge. Za ₀ , za ₁ , za ₂ , za ₃ , za _i−1 , za _i , za _{i + 1} , and zan ₁ shown in FIG. 9 are measured values of the height of the sheet S at the edge.

Curve 330 shown in FIG. 9, at an arbitrary position x ₁ of the end portion in the sheet width direction, and represents the shape of the y-axis direction of the sheet S as viewed from the x-axis direction. When expansion / contraction deformation occurs in the paper width direction, if the leading edge of the paper S is detected by using a step corresponding to the thickness of the paper S to determine the coordinate in the y-axis direction, the position x ₁ indicated by the curve 330 is used. Is different from the coordinate value in the y-axis direction at the position x ₂ indicated by the curve 332. 9, the coordinate value of the y-axis direction at the position x _1, and is matched with the coordinate value of the y-axis direction at the position x _2. The same applies to the curve 332 and the curve 334 shown in FIG.

The calculation unit 210 illustrated in FIG. 3 performs line integration on the total length of the sheet S in the sheet conveyance direction based on the position y _i along the sheet conveyance direction and the measured value of the height za _i of the sheet S at each position y _i. To calculate the length la of the sheet S in the sheet conveyance direction at the end in the sheet width direction. The integration range is the total length of the paper S.

As shown in FIG. 10, in the line integral for calculating the length la of the sheet S at the end in the sheet width direction, the coordinates (y _i−1 , za _i−1 ) and the coordinates (y _i , za _i ) It calculates the distance la _i, the coordinate _{(y i,} za i) calculates the distance _{la i + 1} and the coordinate _{(y i + 1, za i} + 1), adds the distance _{la i + 1} to a distance la _i.

In this way, by calculating the distance la _i and the distance al _{i + 1} and adding the distance la _i and the distance la _{i +} 1 from i = 1 to i = n ₁ , the sheet S at the end in the sheet width direction is obtained. The length la is calculated.

The length lb of the paper S at the non-end portion 300 in the paper width direction shown in FIG. 8 is calculated using the same procedure as the length la of the paper S at the edge in the paper width direction. A broken line indicated by reference numeral 322 in FIG. 8 is a line connecting positions y _{i at} which the height zb _i is measured at the position x ₂ in the paper width direction.

In the measurement of the height zb _i of the sheet S of a plurality of positions y _i along the sheet conveying direction at the position x ₂ in the sheet width direction, firstly, to move the measuring unit 204 shown in FIG. 4 in x _2. Next, measurement values are acquired from the measurement unit 204 at a constant cycle while the measurement unit 204 is moved at a constant speed along the paper conveyance direction.

Velocity v, and measurement conditions such as measurement period T of the measuring unit 204 of the measurement unit 204 in the measurement of the sheet widthwise position x ₂ is applicable to the same conditions as the measurement conditions of the position x ₁ in the sheet width direction . The end SE of the sheet S, and for also detecting the trailing edge SF of the sheet S, it is possible to detect the same manner as in the measurement of the position x ₁ in the sheet width direction.

_Yn2 shown in FIG. 9 corresponds to the rear end SF of the paper S shown in FIG. Zb ₀ , zb ₁ , zb ₂ , zb ₃ , zb _i−1 , zb _i , zb _{i + 1} , and zb _n2 shown in FIG. 9 are measured values of the height of the sheet S at the edge. Dashed curve indicated by symbol 332 in FIG. 9, at an arbitrary position x ₂ of the end portion in the sheet width direction, and represents the shape of the y-axis direction of the sheet S as viewed from the x-axis direction.

The arithmetic unit 210 illustrated in FIG. 3 performs line integration on the total length of the sheet S in the sheet conveyance direction based on the position y _i along the sheet conveyance direction and the measured value of the height zb _i of the sheet S at each position y _i. To calculate the length lb of the sheet S in the sheet conveyance direction at the non-end portion in the sheet width direction.

  The line integration for calculating the length lb of the sheet S at the non-end portion in the sheet width direction is the same as the line integration for calculating the length la of the sheet S at the end portion in the sheet width direction. Here, the description of the line integration for calculating the length lb of the paper S at the non-end portion in the paper width direction is omitted.

  3 compares the length la of the sheet S at the end in the sheet width direction with the length lb of the sheet S at the non-end in the sheet width direction, and calculates a difference dl between the two. To do. The difference dl is expressed using Equation 2 below.

dl = la−lb Equation 2
FIG. 11 is a diagram illustrating an example of a measurement result obtained from the measurement unit when a tight edge is generated. The solid curve indicated by symbol 334 in FIG. 11, when the tight edges on the paper S has occurred, at an arbitrary position x ₁ of the end portion in the sheet width direction, the y-axis direction as viewed from the x-axis direction The shape of the paper S is shown.

_Yn3 shown in FIG. 11 corresponds to the trailing edge SF of the paper S when the paper S has a tight edge. n ₃ is the number of measured values of the height za _i of the paper S at an arbitrary position x ₁ at the end in the paper width direction.

  When a tight edge occurs in the paper S, the end portion of the paper S is greatly reduced compared to the non-end portion of the paper S. Therefore, the length la of the paper S at the end portion is the paper at the non-end portion. It can be less than or equal to the length lb of S. In other words, the difference dl between the length la of the sheet S at the end and the length lb of the sheet S at the non-end in the sheet width direction can be a negative number.

  This makes it difficult to determine both the occurrence of a wave edge and the occurrence of a tight edge using a single threshold value. Therefore, since the difference dl is set to the absolute value | la-lb | of la-lb, it is possible to determine both the occurrence of a wave edge and the occurrence of a tight edge using one threshold value. That is, as the difference dl, it is preferable to apply the absolute value | la-lb | of la-lb represented by the following Expression 3.

dl = | la−lb |
The determination unit 212 illustrated in FIG. 3 determines that expansion / contraction deformation leading to a jam has occurred in the paper S when the difference dl reaches a predetermined threshold value. The determination unit 212 illustrated in FIG. 3 uses the difference in the number of data of the height za _{i of} the paper S and the height zb _i of the paper S to determine the length la of the paper S at the end and the non-end portion. It may be determined that the length lb of the paper S is different. That is, the difference in the number of data may be the difference in the length of the paper S. The length la of the sheet S at the end is an example of the length of the first end. The length lb of the sheet S at the non-end portion is an example of a first reference value and an example of the first non-end portion length. The difference dl is an example of a first calculation value.

In the measurement of the length of the paper S, the variation in the height za _i of the paper S increases when the deformation of the paper S is large. Considering the case where the deformation of the paper S is large, it is possible to ensure measurement accuracy by shortening the measurement cycle.

In consideration of the case where the deformation of the sheet S is large, a nip mechanism by a roller used when separating the sheets S from the sheet feeding table 30 shown in FIG. It is preferable to measure the height za _{i of} the paper S or the height zb _i of the paper S. In other words, it is preferable to measure the height za _{i of} the paper S or the height zb _i of the paper S at a position where the deformation of the paper S is reduced.

  Similarly, the length of the paper S in the paper width direction is calculated for the end portion in the paper transport direction and the non-end portion in the paper transport direction, and based on the length of the paper S in the paper width direction, It is possible to determine whether or not the sheet S has undergone expansion / contraction deformation leading to a jam.

  In the paper transport direction, when it is determined whether or not the expansion and contraction deformation leading to the jam has occurred in the paper S, the paper transport direction corresponds to the first direction. The paper width direction corresponds to the second direction. In the paper width direction, when it is determined whether or not the paper S has undergone expansion / contraction deformation leading to a jam, the paper width direction corresponds to the first direction. The paper transport direction corresponds to the second direction.

  When determining whether or not the paper S has undergone stretching deformation leading to a jam in the paper transport direction and the paper width direction, the paper transport direction corresponds to one of the first direction and the second direction, and the paper width The direction corresponds to the other of the first direction or the second direction.

  The length of the sheet in the first direction at the end portion of the sheet S calculated using the calculation unit 210 shown in FIG. 3 corresponds to the length of the first end portion, and the length of the sheet in the first direction at the non-end portion of the sheet S. The length corresponds to the first non-end length.

  The length of the paper in the second direction at the end of the paper S calculated using the calculation unit 210 corresponds to the length of the second end, and the length of the paper in the second direction at the non-end of the paper S is It is an example of the second reference value and corresponds to the second non-end length.

  The difference between the length of the sheet in the second direction at the end of the sheet S and the length of the sheet in the second direction at the non-end of the sheet S corresponds to the second calculated value. The threshold value applied to the detection of expansion / contraction deformation of the paper S in the second direction corresponds to the second threshold value.

<Flowchart of paper expansion / contraction deformation detection method>
FIG. 12 is a flowchart showing a flow of a procedure for detecting expansion / contraction deformation of a sheet. The detection of expansion / contraction deformation of the paper S is started. First, the end height measurement step S10 is performed. In the edge height measurement step S10, the measurement unit 204 illustrated in FIG. 3 has the height za _i of the sheet S at a plurality of positions with respect to the edge of the sheet S in at least one of the sheet width direction and the sheet conveyance direction. Measure.

12, after the measurement unit 204 shown in FIG. 3 measures the height za _i of the paper S at a plurality of positions with respect to the edge of the paper S, the edge length calculation of FIG. 12 is performed. Proceed to step S12. In the edge length calculation step S12, the calculation unit 210 shown in FIG. 3 uses the height za _i of the paper S measured in the edge height measurement step S10 in FIG. The length l of S is calculated.

In the edge length calculation step S12, the calculation unit 210 shown in FIG. 3 calculates the length la of the paper S at the edge of the paper S, and then the process proceeds to the non-edge height measurement step S14 in FIG. In the non-edge height measurement step S14, the measurement unit 204 illustrated in FIG. 3 has the height of the non-edge portion of the paper S at a plurality of positions with respect to at least one of the non-edge portions in the paper width direction and the paper conveyance direction. Measure zb _i .

12, after the measurement unit 204 shown in FIG. 3 measures the heights zb _i at a plurality of positions for the non-end part of the paper S, the non-end part length calculation in FIG. Proceed to step S16. In the non-edge length calculation step S16, the calculation unit 210 shown in FIG. 3 uses the height zb _i of the paper S measured in the non-edge height measurement step S14 in FIG. The length lb of the paper S in the section is calculated.

  In the non-edge length calculation step S16, the measurement unit 204 shown in FIG. 3 calculates the length lb of the paper S at the non-edge portion of the paper S, and then proceeds to the determination step S18 in FIG. Note that the end length calculation step S12 and the non-end height measurement step S14 can be interchanged.

  The end length calculation step S12 is an example of a component of the calculation step. The non-end length calculation step S16 is an example of a component of the calculation step.

  In the determination step S18, the determination unit 212 shown in FIG. 3 compares the difference dl between the length la of the paper S at the end and the length lb of the paper S at the non-end with a predetermined threshold th. Then, based on the comparison result, it is determined whether or not the sheet S has undergone expansion / contraction deformation leading to a jam. For the difference dl, dl = | la−lb | shown in the above Equation 3 is applied.

In the determination step S18, a plurality of threshold values may be used. For example, in the determination step S18, the wave edge determination threshold th ₁ and the tight edge determination threshold th ₂ may be used. Further, a threshold value th ₃ for expansion / contraction deformation in the paper width direction and a threshold value th ₄ for expansion / contraction deformation in the paper conveyance direction may be prepared. In the determination step S18, the expansion / contraction deformation in the paper width direction and the expansion / contraction deformation in the paper conveyance direction may be determined using different threshold values.

  When the difference dl is less than the threshold th in the determination step S18 of FIG. 12, the determination unit 212 illustrated in FIG. 3 determines that the expansion / contraction deformation leading to the jam has not occurred in the paper S. On the other hand, in the determination step S18 of FIG. 12, when the difference dl is equal to or greater than the threshold th, the determination unit 212 illustrated in FIG. 3 determines that expansion / contraction deformation leading to a jam has occurred in the paper S.

  In the determination step S18 of FIG. 12, the determination unit 212 shown in FIG. 3 determines whether or not the paper S has undergone expansion / contraction deformation leading to a jam, and then proceeds to the determination result output step S20 of FIG. In the determination result output step S <b> 20, the control unit 200 illustrated in FIG. 3 outputs the determination result via the communication unit 202.

  In the determination result output step S20 of FIG. 12, after the control unit 200 shown in FIG. 3 outputs the determination result, the process proceeds to the detection end determination step S22. In the detection end determination step S22, the control unit 200 shown in FIG. 3 determines whether or not to end the detection of the expansion / contraction deformation of the paper. In the detection end determination step S22 of FIG. 12, if the control unit 200 shown in FIG.

  In the case of No determination, the process proceeds to the end height measurement step S10 in FIG. Hereinafter, the respective steps from the end height measurement step S10 to the detection end determination step S22 are repeatedly executed until a Yes determination is made in the detection end determination step S22 of FIG.

  In the detection end determination step S22, if the control unit 200 shown in FIG. In the case of Yes determination, the control unit 200 illustrated in FIG. 3 ends the detection of the expansion / contraction deformation of the paper.

  The control unit 200 illustrated in FIG. 3 can execute a procedure for detecting expansion / contraction deformation of the paper S illustrated in FIG. 12 by executing an expansion / contraction deformation detection program.

  The threshold value th in the determination step S18 is an example of a first threshold value. When the expansion / contraction deformation detection of the paper S is executed in both the paper conveyance direction and the paper width direction, the threshold value used for detection of the expansion / contraction deformation of the paper S in the second direction is an example of the second threshold value. .

[Function and effect]
According to the detection apparatus and the detection method configured as described above, the heights za _i of the sheet S at a plurality of positions at the end of the sheet S are measured, and the sheet at a plurality of positions at the end of the sheet S is measured. The length la at the edge of the paper S is calculated from the height za _i of S. Further, to measure the height zb _i of S of the sheet at a plurality of locations in the non-edge portion 300 of the sheet S, from a height zb _i of S of the sheet at a plurality of locations in the non-edge portion 300 of the sheet S of the sheet S The length lb at the non-end portion 300 is calculated.

  By comparing the difference dl between the length la at the end of the paper S and the length lb at the non-end portion 300 of the paper S with a predetermined threshold th, is the paper S undergoing stretching deformation leading to a jam? Determine whether or not. As a result, it is possible to detect the paper S in which expansion / contraction deformation leading to a jam has occurred.

[Modification]
<Measurement range of paper height, calculation range of paper length>
In the present embodiment, the height of the sheet S is measured for the entire length of the sheet S, but the height of the sheet S may be measured for a part of the sheet S. When measuring the height of the paper S for a part of the paper, the measurement range can be determined using the number of measurement positions and the measurement period.

  For example, when detecting expansion / contraction deformation in the paper transport direction, the height of the paper S may be measured by measuring the height of the paper S in at least a part of the non-end portion 300 in the paper transport direction. As an example of the measurement range of the height of the paper S, a range indicated by reference numeral 324 in FIG.

  The detection of the expansion / contraction deformation of the sheet utilizes the fact that the end portion of the sheet is easily stretched and deformed and the non-end portion of the sheet is not easily deformed. For example, the expansion / contraction deformation in the paper transport direction is based on the difference between the length of the paper S in the paper transport direction at the end in the paper width direction and the length of the paper S in the paper transport direction at the non-end portion 300 in the paper width direction. Can be judged.

  It is considered that both the end in the sheet width direction at the leading end 306 in the sheet conveying direction and the non-end in the sheet width direction at the leading end 306 in the sheet conveying direction are easily stretched and deformed. Then, the difference between the length of the end in the paper width direction at the front end 306 in the paper transport direction and the length of the non-end in the paper width direction at the front end 306 in the paper transport direction is very small.

  Therefore, when calculating the length of the sheet S in the sheet conveyance direction, even if the leading end 306 in the sheet conveyance direction and the rear end 308 in the sheet conveyance direction are excluded, the influence on the detection result of expansion / contraction deformation is small. Conceivable.

  Further, the length of the sheet S at the end in the sheet width direction and the length of the sheet S at the non-end in the sheet width direction may be calculated for a part of the total length of the non-end in the sheet conveyance direction. When calculating the length of the sheet S for a part of the sheet S, the integration range of the line integral is the height measurement range.

  When calculating the length of the paper S for a part of the paper S, the detector uses the timing at which a step corresponding to the thickness of the paper S is detected, the speed of the detector, and the length of the edge of the paper S. It is possible to grasp the timing of entering the non-edge portion of the paper S. The end timing of the measurement range of the height of the paper S can be determined using the elapsed period from the timing when the level difference corresponding to the thickness of the paper S is detected.

  The level difference corresponding to the thickness of the paper S is an example of a change in the measured value corresponding to the thickness of the medium. The timing at which the level difference corresponding to the thickness of the paper S is detected is an example of the reference timing. The speed of the detector is an example of the relative moving speed between the medium and the measurement unit.

  On the other hand, the calculation for calculating the length of the sheet S can improve the accuracy as the number of samples is larger. Therefore, the length of the sheet S at the end in the sheet width direction with respect to the total length of the non-end in the sheet transport direction, It is also preferable to calculate the length of the paper S at the non-end portion in the paper width direction.

  The case of detecting expansion / contraction deformation in the paper width direction is the same as the case of detecting expansion / contraction deformation in the paper conveyance direction.

  Further, when the origin of the paper S is an arbitrary one of the four corners SC of the paper S, when detecting a step corresponding to the thickness of the paper S and detecting the leading edge SE of the paper S, the height measurement range of the paper S is set. The edge part of the paper S in a direction orthogonal to the direction of the measurement target may be included. When measuring the height of the paper S in the paper transport direction, the leading end 306 of the paper S in the paper transport direction shown in FIG. 7 may be included in the measurement range.

<Modification of paper length>
The height of the paper S may be measured at both ends of the paper S. When measuring the height of the paper S in the paper transport direction, the height of the paper S in the paper transport direction is measured for one end 302 in the paper width direction, and for the other end 304 in the paper width direction. The height of the paper S in the paper transport direction may be measured.

  Based on the respective measurement results, the length of the sheet S in the sheet conveyance direction at one end 302 in the sheet width direction and the length of the sheet S in the sheet conveyance direction at the other end 304 in the sheet width direction. May be calculated.

  A representative value of the length of the sheet S in the sheet conveyance direction at one end 302 in the sheet width direction and the length of the sheet S in the sheet conveyance direction at the other end 304 in the sheet width direction is the sheet S in the sheet conveyance direction. It may be the length of. The maximum value may be applied as the representative value.

Further, the length of the paper S may be calculated for a plurality of positions of the non-end portion 300 of the paper S. For example, the length of the sheet S in the sheet conveyance direction may be calculated for the position x _{2 in} the x-axis direction and the position x _{3 in} the x-axis direction illustrated in FIG.

length, and the representative value of the length of the sheet S at the position x ₃ in the x-axis direction, the length of the sheet S in the sheet conveying direction in the non-edge portion 300 of the sheet S of the sheet S at the position x ₂ in the x-axis direction It is good. The maximum value may be applied as the representative value.

<Modification of difference calculation>
In the present embodiment, the difference dl between the length la of the paper S at the end and the length lb of the paper S at the non-end is used, but the length lb of the paper S at the non-end is also a fixed value. Good. Since the non-end portion hardly undergoes expansion and contraction, it is considered that there is no practical problem even if it is replaced with a fixed value.

  As an example of the fixed value, the standard value of the paper S may be applied. Further, measurement values of some of the sheets S in the plurality of sheets S, such as measurement values of the first sheet S in the plurality of sheets S, may be applied. The fixed value serving as the reference value may be stored in the storage unit 214 illustrated in FIG. The fixed part is an example of a first reference value.

<Modification of measurement unit>
The measuring unit 204 shown in FIG. 4 may include a plurality of measuring devices, and may measure the edge of the paper S and the non-edge of the paper S using separate measuring devices.

[Description of Paper Feeding Method in Inkjet Recording Apparatus]
FIG. 13 is a flowchart showing a flow of a procedure of a paper feeding method in the ink jet recording apparatus shown in FIG. The paper feeding method is started. First, in the paper feed start command acquisition step S <b> 100, the paper feed control unit 112 illustrated in FIG. 2 acquires the paper feed start command transmitted from the system controller 100.

  In the paper feed start command acquisition step S100 of FIG. 13, after the paper feed control unit 112 shown in FIG. 2 acquires the paper feed start command transmitted from the system controller 100, the process proceeds to the paper discharge determination step S102 of FIG.

  In the paper discharge determination step S102, the paper feed control unit 112 shown in FIG. 2 has acquired a determination result indicating that the paper S has undergone expansion / contraction deformation, or the paper feed control unit 112 reaches a jam. It is determined whether or not a determination result indicating that expansion and contraction deformation has not occurred in the paper S has been acquired.

  In the paper discharge determination step S102 of FIG. 13, if the paper feed control unit 112 shown in FIG. 2 acquires a determination result indicating that the paper S has not undergone expansion / contraction deformation, a No determination is made. In the case of No determination, the process proceeds to the paper feed process step S104 in FIG. In the paper feed processing step S104, the paper feed control unit 112 in FIG. 2 controls the operation of the paper feed unit 12 to perform paper feed.

  In the paper feed processing step S104 of FIG. 13, after the paper feed unit 12 shown in FIG. 2 feeds the paper S, the process proceeds to the paper feed end determination step S108 of FIG.

  On the other hand, in the paper discharge determination step S102 of FIG. 13, if the paper feed control unit 112 shown in FIG.

  In the case of Yes, the process proceeds to the paper discharge process step S106 in FIG. In the paper discharge processing step S106, the paper feed control unit 112 shown in FIG. 2 controls the operation of the deformed paper discharge unit 26 and discharges the paper S that has undergone expansion / contraction deformation from the paper feed unit 12 to the jam. To do. The paper S discharged using the modified paper discharge unit 26 may be subjected to a regeneration process such as seasoning.

  The sheet S that has undergone expansion / contraction deformation leading to a jam is subjected to a regeneration process such as seasoning, so that the moisture distribution becomes uniform and can be reused. In the case of reusing the paper S that has undergone expansion / contraction deformation leading to a jam, an effect of reducing the waste paper can be obtained.

  In the paper discharge processing step S106 in FIG. 13, after the modified paper discharge unit 26 shown in FIG. 2 discharges the paper S, the process proceeds to the paper feed end determination step S108 in FIG.

  In the paper feed end determination step S108, the paper feed control unit 112 shown in FIG. 2 determines whether or not the number of sheets S fed from the paper feed unit 12 has reached a predetermined number of paper feeds. . In the paper feed end determination step S108 of FIG. 13, if the number of sheets S fed from the paper feed unit 12 has not reached the predetermined number of paper feeds, the determination is No.

  In the case of No determination, the process proceeds to the paper feed start command acquisition step S100 in FIG. Thereafter, the processes from the paper feed start command acquisition process S100 to S108 are repeatedly executed until a Yes determination is made in the paper feed end determination process S108.

  On the other hand, if it is determined in the paper feed end determination step S108 in FIG. 13 that the number of sheets S fed from the paper feed unit 12 has reached a predetermined number of sheets, the determination is Yes. In the case of Yes determination, the paper feed control unit 112 illustrated in FIG. 2 ends the paper feed method.

[Operational effect of paper feeding method in inkjet recording apparatus]
When the paper S in which the expansion / contraction deformation leading to the jam occurs is detected, the paper S in which the expansion / contraction deformation leading to the jam occurs is discharged from the paper feeding unit 12. As a result, it is possible to remove a sheet that has undergone expansion / contraction deformation leading to a jam before feeding.

  Further, due to the suppression of the occurrence of the jam of the paper S, the operation stop of the ink jet recording apparatus 10 due to the occurrence of the jam of the paper S can be suppressed, and the operation rate of the ink jet recording apparatus 10 can be improved.

[Variation of paper feeding method]
When the paper S in which the expansion / contraction deformation leading to the jam occurs is detected, and the thickness of the paper S is thin, the suction pressure can be dynamically controlled to suppress the jam. That is, if the thickness of the paper S acquired using the thickness information acquisition unit 128 shown in FIG. 2 is equal to or smaller than a predetermined thickness, even the paper S that has undergone expansion / contraction deformation leading to jamming. The paper is fed without being ejected.

  The transport control unit 110 shown in FIG. 2 uses a suction pressure applying unit (not shown) when the paper S having a predetermined thickness or less and having undergone expansion and contraction deformation leading to a jam is fed. Thus, the suction pressure applied to the paper S is controlled. The control of the adsorption pressure includes both a case where the adsorption pressure is increased and a case where the adsorption pressure is decreased.

[Other device application examples]
In the present embodiment, the detection device 13 that detects the paper S in which the expansion / contraction change to the jam has occurred in the paper of the paper feeding unit 12 of the inkjet recording apparatus 10 has been exemplified. The detection device 13 can be applied to a detection device that detects a sheet-like medium in which expansion / contraction deformation exceeding an allowable range occurs in a conveyance device that conveys a medium.

  As an example of the conveyance device, a conveyance device that conveys a medium in a processing region of a processing unit that performs a predetermined process on a sheet-like medium is given. Examples of the predetermined process include a liquid application process, a heating process, a drying process, and a cutting process.

  In the embodiment of the present invention described above, the configuration requirements can be appropriately changed, added, and deleted without departing from the spirit of the present invention. The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the field within the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 10 Inkjet recording device 11 Conveyance part 12 Paper feed part 13 Detection apparatus 14 Processing liquid application part 16 Processing liquid drying process part 18 Drawing part 20 Ink drying process part 24 Paper discharge part 26 Deformation paper discharge part 30 Paper feed stand 34 Paper feed roller Pair 36 Feeder board 36A Retainer 36B Guide roller 38 Front pad 40 Feed drums 40A, 42A, 46A, 52A, 64D Gripper 40B, 42B, 46B, 52B Rotating shaft 42 Treatment liquid drums 42C, 46C, 52C Outer peripheral surface 44 Treatment liquid application Device 46 Processing liquid drying processing drum 48 Paper transport guide 50 Processing liquid drying processing unit 52 Drawing drum 54 Paper pressing rollers 56, 56C, 56M, 56Y, 56K Liquid discharge head 58 In-line sensor 64 Chain gripper 64A First sprocket 64B Second sprocket 64C h Over emissions 68 ink drying processing units 72 and 73 the guide plate 76 discharge tray 100 system controller 100A CPU
100B ROM
100C RAM
102 communication unit 103 host computer 104 image memory 110 transport control unit 112 paper feed control unit 114 processing liquid application control unit 116 processing liquid drying control unit 118 drawing control unit 120 ink drying control unit 124 paper discharge control unit 126 deformed paper discharge control unit 128 thickness information acquisition unit 130 operation unit 132 display unit 134 parameter storage unit 136 program storage unit 200 control unit 202 communication unit 204 measurement unit 206 first movement unit 208 second movement unit 210 calculation unit 212 determination unit 214 storage unit 240 carriage 242 Width direction guide 260 First transport direction guide 262 Second transport direction guide 264 First support portion 266 Second support portion 300 Non-end portion 302, 304 End portion 306 Front end portion 308 Rear end portion 320, 322 Line connecting measurement positions 324 Measurement range 330, 332, 334 Curve la The length of the paper at the end of the paper lb The length of the paper at the non-edge of the paper S The paper SA The first surface SB Four sides SC, SC ₁ Four corners SD Central part SE The front edge SF The rear edges x ₁ , x ₂ , x _{3 y 0, y 1, y 2} , y 3, y i-1, y i, y i + 1, y n1, y n2, y n3 y -axis direction position _{za 0, za 1, za 2} , za 3, za i ₋₁ , za _i , za _{i + 1} , za _n1 , za _n3 , zb ₀ , zb ₁ , zb ₂ , zb ₃ , zb _i−1 , zb _i , zb _{i + 1} , zb _n2 sheet height S10 to S22 Each step S100 to S108 Each step of the paper feeding method

Claims (21)

For the first surface of the sheet-like medium, a measurement unit that measures the height of a plurality of positions in the first direction,
A calculation unit that calculates a length on the first surface of the medium in the first direction using the measurement result of the measurement unit;
A determination unit that determines whether the deformation of the medium is within an allowable range based on the length on the first surface of the medium in the first direction calculated using the calculation unit;
With
The measurement unit is configured to measure the height of a plurality of positions in the first direction with respect to a range including at least a non-end part in the first direction with respect to the end of the medium in the second direction orthogonal to the first direction. Measure and
The computing unit has a first end which is a length on the first surface of the medium in the first direction corresponding to a range measured using the measuring unit with respect to the end of the medium in the second direction. Calculating the head length, and performing a calculation to calculate a first calculation value representing a difference or ratio between the first end length and the first reference value,
The determination unit is a detection device that determines whether the deformation of the medium in the first direction is within an allowable range based on a comparison result between the first calculation value and a predetermined first threshold value. The measuring unit measures the height of a plurality of positions in the first direction with respect to the end of the medium in the second direction, with respect to the total length of the medium in the first direction.
The detection device according to claim 1, wherein the calculation unit calculates the first end length corresponding to the total length of the medium in the first direction with respect to the end of the medium in the second direction.   The detection device according to claim 1, wherein the calculation unit performs line integration with the measurement range of the measurement unit as an integration range for the measurement result obtained from the measurement unit, and calculates the first end length. . The measurement unit measures the height of a plurality of positions in the first direction for a range including at least the non-end portion in the first direction with respect to the non-end portion of the medium in the second direction,
The computing unit is a length on the first surface of the medium in the first direction corresponding to a range measured using the measuring unit with respect to the non-end portion of the medium in the second direction. The detection device according to any one of claims 1 to 3, wherein a non-end length is calculated and calculation is performed using the first non-end length as the first reference value. The measurement unit measures the heights of a plurality of positions in the first direction with respect to the total length of the medium in the first direction for the non-end portion of the medium in the second direction,
The detection device according to claim 4, wherein the calculation unit calculates the first non-end length corresponding to the total length of the medium in the first direction for the non-end portion of the medium in the second direction.   The detection according to claim 4 or 5, wherein the calculation unit performs line integration with the measurement range of the measurement unit as an integration range for the measurement result obtained from the measurement unit, and calculates the first non-end length. apparatus.   The detection device according to any one of claims 1 to 6, wherein the measurement unit includes a non-contact type measurement device or a contact type measurement device.   The detection device according to claim 7, further comprising a first relative movement unit that relatively moves the non-contact type measuring device or the contact type measuring device and the medium in the first direction.   The detection device according to claim 7, further comprising a second relative movement unit that relatively moves the non-contact type measuring device or the contact type measuring device and the medium in the second direction.   The measurement unit measures the height using the relative movement speed of the medium and the measurement unit and the elapsed time from the reference timing, with the timing at which the measurement value corresponding to the thickness of the medium has occurred as the reference timing. The detection device according to claim 8 or 9, wherein a range is determined. The measurement unit measures the height of a plurality of positions in the second direction for a range including at least a non-end part in the second direction with respect to the end of the medium in the first direction,
The computing unit has a second end that is a length on the first surface of the medium in the second direction corresponding to a range measured using the measuring unit with respect to the end of the medium in the first direction. Calculating the section length and performing a calculation to calculate a second calculation value representing a difference or ratio between the second end section length and the second reference value;
The determination unit determines whether the deformation of the medium in the second direction is within an allowable range based on a comparison result between the second calculated value and a predetermined second threshold value. The detection device according to any one of the above. The measuring unit measures the height of a plurality of positions in the second direction with respect to the end of the medium in the first direction, targeting the total length of the medium in the second direction,
The detection device according to claim 11, wherein the calculation unit calculates the second end length corresponding to the total length of the medium in the second direction with respect to the end of the medium in the first direction. The measurement unit measures the range including the end of the medium in the second direction and the non-end of the medium in the second direction for the non-end of the medium in the first direction,
The calculation unit calculates a second non-end length, which is a length on the first surface of the medium in the second direction, for the non-end portion of the medium in the first direction, and the second non-end The detection device according to claim 11, wherein the calculation is performed using the section manager as the second reference value. The measurement unit measures the heights of a plurality of positions in the second direction for the non-end portion of the medium in the first direction, with respect to the total length of the medium in the second direction,
The detection device according to claim 13, wherein the calculation unit calculates the second non-end length corresponding to the total length of the medium in the second direction for the non-end portion of the medium in the first direction. The edge of the media is within 50 millimeters of the edge of the media;
The detection device according to any one of claims 1 to 14, wherein the non-end portion of the medium has a range exceeding 50 millimeters from an end of the medium. For the first surface of the sheet-like medium, a measuring step for measuring the height of a plurality of positions in the first direction;
Using the measurement result of the measurement step, a calculation step for calculating the length on the first surface of the medium in the first direction;
A determination step of determining whether the deformation of the medium is within an allowable range based on the length on the first surface of the medium in the first direction calculated in the calculation step;
Including
In the measurement step, with respect to an end portion of the medium in the second direction orthogonal to the first direction, the height of a plurality of positions in the first direction is targeted at a range including at least a non-end portion in the first direction. Measure and
In the calculation step, with respect to the end portion of the medium in the second direction, the first end length corresponding to the range measured in the measurement step, which is the length on the first surface of the medium in the first direction, is calculated. And calculating to calculate a first calculation value representing a difference or ratio between the first end length and the first reference value,
The determination step is a detection method for determining whether the deformation of the medium in the first direction is within an allowable range based on a comparison result between the first calculation value and a predetermined first threshold value. A transport unit for transporting a sheet-like medium;
For the first surface of the medium, a measurement unit that measures the height of a plurality of positions in the first direction;
A calculation unit that calculates a length on the first surface of the medium in the first direction using the measurement result of the measurement unit;
A determination unit that determines whether the deformation of the medium is within an allowable range based on the length on the first surface of the medium in the first direction calculated using the calculation unit;
With
The measurement unit is configured to measure the height of a plurality of positions in the first direction with respect to a range including at least a non-end part in the first direction with respect to the end of the medium in the second direction orthogonal to the first direction. Measure and
The computing unit has a first end which is a length on the first surface of the medium in the first direction corresponding to a range measured using the measuring unit with respect to the end of the medium in the second direction. Calculating the head length, and performing a calculation to calculate a first calculation value representing a difference or ratio between the first end length and the first reference value,
The determination unit is a transport device that determines whether the deformation of the medium in the first direction is within an allowable range based on a comparison result between the first calculation value and a predetermined first threshold value. An inkjet head that ejects ink onto a sheet-like medium;
A transport unit for transporting the medium;
For the first surface of the medium, a measurement unit that measures the height of a plurality of positions in the first direction;
A calculation unit that calculates a length on the first surface of the medium in the first direction using the measurement result of the measurement unit;
A determination unit that determines whether the deformation of the medium is within an allowable range based on the length on the first surface of the medium in the first direction calculated using the calculation unit;
With
The measurement unit is configured to measure the height of a plurality of positions in the first direction with respect to a range including at least a non-end part in the first direction with respect to the end of the medium in the second direction orthogonal to the first direction. Measure and
The computing unit has a first end which is a length on the first surface of the medium in the first direction corresponding to a range measured using the measuring unit with respect to the end of the medium in the second direction. Calculating the head length, and performing a calculation to calculate a first calculation value representing a difference or ratio between the first end length and the first reference value,
The determination unit is an ink jet recording apparatus that determines whether the deformation of the medium in the first direction is within an allowable range based on a comparison result between the first calculated value and a predetermined first threshold value. A medium thickness information acquisition unit for acquiring information on the thickness of the medium;
The transport unit includes an adsorption pressure application unit that applies an adsorption pressure to the medium and adsorbs and supports the medium.
The inkjet recording apparatus according to claim 18, wherein the adsorption pressure applying unit controls the magnitude of the adsorption pressure applied to the medium based on the thickness information of the medium acquired using the medium thickness information acquiring unit. A medium supply unit for supplying a medium to the transport unit;
The inkjet recording apparatus according to claim 18, wherein the measurement unit is provided in the medium supply unit.   21. The ink jet recording apparatus according to claim 18, further comprising a discharge unit that discharges the medium from the transport unit when it is determined that the deformation of the medium exceeds an allowable range using the determination unit. .

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