JP2015108598A - Sizing degree detection device, sizing degree detection method, image formation device, and image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sizing degree detection device capable of measuring sizing degree with no individual difference in measurement results.SOLUTION: A sizing degree detection device includes a discharge part 11 for making a droplet stick to a sheet material, a detection part 12 which, before and after the time point at which the droplet is made to stick to a sheet material SH by the discharge part 11, detects thermal conductivity of gas near the sticking part of the sheet material SH, and calculation means which, comparing with the thermal conductivity before sticking of the droplet which is detected by the detection part 12, acquires passage of time from the time point when the thermal conductivity after the sticking that is detected by the detection part 12 changes to be a predetermined ratio or higher, and acquires sizing degree of the sheet material SH based on a relationship between the passage of time and the sizing degree of the sheet material SH.

Description

  The present invention relates to a sizing degree detecting device and a sizing degree detecting method for detecting a sizing degree of a sheet material on which an image is formed, and an image forming apparatus and an image forming method provided with the sizing degree detecting device.

  Conventionally, a number of items including thickness, density, fiber direction, smoothness, air permeability, sizing, etc., as printing characteristics of paper or recording media (hereinafter referred to as sheet material) on which images are formed. It has been known. There are many items representing the properties or quality of the sheet material as shown in the list of Japanese Industrial Standard P items (pulp and paper), for example.

  For example, Japanese Industrial Standard JIS P 8122 describes a Steecht size method that can measure the sizing degree corresponding to the penetration resistance of water.

  Patent Document 1 discloses an image forming apparatus including a detection device that calculates the thickness and type of a sheet material for the purpose of improving image quality.

  In the former measurement method, measurement preparation is troublesome, and there is a problem that individual measurement results vary due to visual observation.

  Further, the latter image forming apparatus has a problem that the size of the sheet material cannot be obtained.

  An object of the present invention is to provide a sizing degree measuring apparatus capable of measuring the sizing degree without causing individual differences in measurement results.

The invention of claim 1 is an attachment means for attaching droplets to a sheet material;
Detection means for detecting the thermal conductivity or humidity of the gas in the vicinity of the adhesion portion of the sheet material before and after the time point when the droplet is adhered to the sheet material by the adhesion means;
The time until the thermal conductivity or humidity after adhesion detected by the detection means changes to a predetermined ratio or more as compared to the thermal conductivity or humidity before adhesion of the droplet detected by the detection means. And calculating means for determining the sizing degree of the sheet material based on the relationship between the elapsed time and the sizing degree of the sheet material.

  According to this invention, there is no individual difference in the measurement result of the sizing degree, and the sizing degree of the sheet material can be measured.

1 is a side view showing a schematic configuration of an image forming apparatus according to the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a detection head of a sizing degree measurement device mounted on the image forming apparatus illustrated in FIG. 1. It is a top view which shows the structure of the detection head shown in FIG. It is the block diagram which showed the structure of the sizing degree measuring apparatus. It is explanatory drawing which showed the other example of the detection head shown in FIG. It is explanatory drawing of the graph which showed the relationship between heat conduction change time and a sizing degree. It is the table | surface which showed the relationship between sizing degree and droplet amount correction | amendment. It is the table | surface which showed the relationship between a degree of size and thermal history correction | amendment. It is the flowchart which showed operation | movement of the sizing degree measuring apparatus. It is the graph which showed the relationship between time and thermal conductivity. It is explanatory drawing which showed the image forming apparatus of the other example. FIG. 6 is an explanatory diagram illustrating a paper feeding unit of another example of the image forming apparatus. It is the top view which showed the structure of the detection head of 2nd Example. It is sectional drawing which shows the structure of the detection head shown in FIG. It is sectional drawing which shows the structure of the detection head of 3rd Example. It is a top view which shows the structure of the detection head of 3rd Example. It is sectional drawing which shows the structure of the detection head of 4th Example. It is a top view which shows the structure of the detection head of 4th Example. It is a top view which shows the structure of the detection head of 5th Example. It is sectional drawing which shows the structure of the detection head of 6th Example. It is a top view which shows the structure of the detection head of 6th Example. It is sectional drawing which shows the structure of the detection head of 7th Example. It is a top view which shows the structure of the detection head of 7th Example. It is sectional drawing which shows the structure of the detection head of 8th Example.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a sizing degree detection apparatus that performs a sizing degree detection method according to the present invention and an image forming apparatus that includes the sizing degree detection apparatus and that performs an image forming method will be described with reference to the drawings. To do.

[First embodiment]
FIG. 1 shows an inkjet image forming apparatus 100 including a sizing degree detection apparatus 10 (see FIG. 4) that performs the sizing degree detection method.

The image forming apparatus 100 includes a paper feed mechanism 120, a carriage 105 having a print head 110, a drive mechanism 130 that moves the carriage 105, a transfer mechanism 140, and a sizing degree detection device 10 that detects the sizing degree of the sheet material SH. Etc.
[Paper feeding mechanism and transfer mechanism]
The paper feed mechanism 120 includes a paper feed roller (not shown) and a paper presser roller 101 for feeding the sheet material SH placed on the paper feed tray 109 to the image forming unit 50.

The transfer mechanism 140 includes a pair of transfer rollers 141A and 141B that transfer the sheet material SH fed by the paper feed mechanism 120 to the image forming unit 50, and a sheet discharge roller (not shown) that forms the image-formed sheet material SH. And a pair of transfer rollers 142A and 142B.
[Print head]
The print head 110 has a nozzle hole (not shown) for ejecting ink and a piezoelectric element for ejecting ink from the nozzle hole, and the configuration thereof is the same as the conventional one. Therefore, the explanation is omitted.
[carriage]
The carriage 105 is movably provided along a main shaft 104 provided along a direction orthogonal to the sheet discharge direction of the sheet material SH (a direction orthogonal to the paper surface of FIG. 1). An ink cartridge 106 is detachably attached to the carriage 105, and the ink cartridge 106 is provided with ink of four colors, for example, cyan, magenta, yellow, and black.
[Drive mechanism]
The drive mechanism 130 includes a drive motor 102, a drive belt 103, and the like, and the carriage 105 is moved along the main shaft 104 by rotating the drive belt 103 by the drive motor 102. Yes.
[Sizing degree detector]
As shown in FIGS. 2 and 3, the sizing degree detection device 10 includes a detection head 10H for detecting thermal conductivity. The detection head 10H includes a discharge unit (attachment unit) 11 that discharges droplets onto the sheet material SH, and a detection unit 12 that detects thermal conductivity. The ejection unit 11 and the detection unit 12 are provided on the carriage 105.
[Discharge part]
The ejection unit 11 includes a nozzle hole (not shown) for ejecting liquid droplets and a piezoelectric element (not shown) for ejecting liquid droplets from the nozzle hole. It has become a structure.

  The discharge part 11 is surrounded by a side wall part 11Hs of a rectangular parallelepiped hollow partition member (closed space forming member) 11H having an open bottom surface, and around the droplet Q dropped on the sheet material SH. It is designed to surround. That is, the partition member 11H forms a closed space 11Ha whose bottom surface is open.

In addition, the opening on the lower surface of the partition member 11H is closed by the sheet material SH, and when the opening is closed by the sheet material SH, the closed space 11Ha is almost the same if the air permeability of the sheet material SH is ignored. Sealed. The discharge portion 11 is arranged in the space portion 11Ha.
[Detection unit]
As shown in FIG. 2, the detection unit 12 detects the thermal conductivity of the gas on the predetermined position P2 of the sheet material SH that is separated from the dropping position (droplet adhesion point) P1 of the sheet material SH by a predetermined distance L1. It is.

The detection unit 12 is a position sandwiching the dropping position P1, and as shown in FIG. 3, the sheet material SH feed direction (paper discharge direction) Y and the sheet material SH width direction X orthogonal to the feed direction Y And four detectors 12A to 12D arranged respectively.
[Detector]
As shown in FIG. 2, the detector 12A has a package (closed space forming member) 201 provided on the lower surface of the circuit board 200, a sensor chip (detection means) 12SA provided in the package 201, and the like. doing. Reference numeral 20 denotes a cradle for receiving the sheet material SH.

  The mounting position of the sensor chip 12SA is set at a position separated from the ejection unit 11 by a predetermined distance L1.

  The package 201 has a lower surface opened and is partitioned and formed as a space portion 201A. The package 201 has an upper wall portion 201B and a peripheral wall portion 201C having a predetermined height. That is, the package 201 forms a closed space whose bottom surface is open.

  A sensor chip 12SA is attached to the lower surface of the upper wall portion 201B of the package 201, and the opening 201e on the lower surface is covered with a moisture permeable film 210.

  The package 201 and the moisture permeable film 210 form a sealed space 201A that is not affected by an external gas, and the sensor chip 12SA is disposed in the sealed space 201A.

  The sensor chip 12SA has a thermal conductivity detection sensor that detects the thermal conductivity of the space 201A, and this thermal conductivity detection sensor has the same principle as that described in Japanese Patent No. 2889909. The description is omitted here.

  In order to more accurately measure the thermal conductivity of the gas in the space 201A, it is preferable to install the sensor chip 12SA as close as possible to the sheet material SH.

  A base 250 is provided outside the peripheral wall portion 201C of the package 201, and the height of the base 250 is set so that the lower surface of the base 250 and the surface (lower surface) of the moisture permeable membrane 210 are flush with each other. ing. This is because the output of the detector 12A is reduced because foreign matters such as paper dust generated from the sheet material SH adhere to the lower surface of the moisture permeable film 210 while the sheet material SH is repeatedly conveyed. This is to prevent the response of 12A from being delayed.

  Since the detectors 12B to 12D have the same configuration as the detector 12A, the description thereof is omitted.

The stand 250 may be disposed between the side wall 11Hs of the partition member 11H and the peripheral wall 201C of the package 201 as shown in FIG. 4A.
[Control system]
FIG. 4 is a block diagram illustrating a configuration of the sizing degree detection apparatus 10. The sizing degree detection apparatus 10 includes a storage unit 13 that stores tables F1 to F3 described later, a clock unit 14 that measures time, an image formation condition control unit (image formation condition control unit) 15, and a drying condition control unit. 16 and a control unit (calculation means) 17.

  The storage unit 13 stores various data obtained by the control unit 17.

  As shown in FIG. 5, the table F1 is a graph showing the relationship between the elapsed time (heat conduction change time) t2 from the time when the droplet is dropped until the thermal conductivity reaches a predetermined thermal conductivity, and the sizing degree. It is.

  The table F2 is a table showing the relationship between the sizing degree and the correction of the droplet discharge amount of the print head 110, as shown in FIG.

  The table F3 is a table showing the relationship between the sizing degree and the correction of the drying conditions of the image forming apparatus 100 as shown in FIG.

  The image forming condition control unit 15 sets predetermined image forming conditions based on the table F2 indicating the relationship between the sizing degree and the image forming conditions from the sizing degree detected by the control unit 17.

  The drying condition control unit 16 sets predetermined drying conditions based on the table F3 indicating the relationship between the sizing degree and the drying conditions from the sizing degree detected by the control unit 17.

  The control unit 17 controls the discharge unit 11, the detection unit 12, the storage unit 13, the clock unit 14, the image forming condition control unit 15, and the drying condition control unit 16. The control unit 17 executes sheet material sizing degree detection processing and image forming condition setting processing, which will be described later, and detects the sizing degree of the sheet material SH and sets image forming conditions.

The control unit 17 is controlled by the control device 117 of the image forming apparatus 100 shown in FIG.
[Operation]
Next, operations of the sizing degree detection apparatus 10 and the image forming apparatus 100 configured as described above will be described based on a flowchart shown in FIG.

  In step 11, first, as shown in FIG. 1, the sheet material SH placed on the paper feed tray 109 is fed to the image forming unit 50 by the control device 117. Before the droplets are ejected from the print head 110 to the fed sheet material SH, the detection unit 12 detects and detects the thermal conductivity (reference thermal conductivity) of the space above the predetermined position of the sheet material SH. Based on the detection signal of the unit 12, the control unit 17 obtains the reference thermal conductivity. The control unit 17 stores the obtained reference thermal conductivity in the storage unit 13.

  In step 12, the control unit 17 discharges droplets from the discharge unit 11 onto the surface of the sheet material SH, obtains the time T 0 when the droplets are discharged from the clock unit 14, and stores the time T 0 in the storage unit 13.

  In step 13, the control unit 17 discharges droplets from the discharge unit 11, and then obtains the thermal conductivity of the space on the predetermined position P2 of the sheet material SH based on the detection signal detected by the detection unit 12, The obtained thermal conductivity is stored in the storage unit 13.

  This is because the change in the thermal conductivity of the gas in the vicinity of the sheet material SH caused by the droplet adhesion, that is, the change in humidity is measured at the detection position P2 separated from the droplet adhesion point P1 by a predetermined distance L1, The difference in the speed of penetration of the droplets into the sheet material SH due to the above is captured.

  In Step 14, it is determined whether or not the thermal conductivity obtained in Step 13 has increased by 10% or more with respect to the reference thermal conductivity obtained in Step 12, and if no, the process returns to Step 13. That is, the processing operations of Step 13 and Step 14 are repeated until the thermal conductivity obtained in Step 13 increases by 10% or more with respect to the reference thermal conductivity. If the thermal conductivity increases by 10% or more with respect to the reference thermal conductivity, it is determined as YES and the process proceeds to step 15.

  In step 15, the control unit 17 obtains the time T <b> 1 when the thermal conductivity has increased by 10% or more with respect to the reference thermal conductivity from the clock unit 14 and stores it in the storage unit 13.

  In step 16, the control unit 17 calculates an elapsed time (T 1 -T 0: change time) t 2 between time T 0 and time T 1, and stores this change time t 2 in the storage unit 13.

  By the way, since the detection part 12 has four detectors 12A-12D as shown in FIG. 3, in each predetermined position corresponding to each detector 12A-12D, until thermal conductivity increases 10%. Each change time t2 is obtained.

  In step 17, an average value or a total value of the change times t2 of the sheet material SH in the X and Y directions is calculated with reference to the droplet attachment point (drop position) P1, and the calculated change times t2x and t2y are stored in the storage unit. 13.

  Here, assuming that the change times t2 of the detectors 12A to 12D are t2xa, t2xb, t2ya, and t2yb in this order, the control unit 17 sums up the change times t2 in the X and Y directions. That is, the control unit 17 calculates t2x = t2xa + t2xb and t2y = t2ya + t2yb. The change times t2x, t2y may be average times (t2ya + t2yb) / 2, (t2ya + t2yb) / 2.

  FIG. 9 shows the relationship between the thermal conductivity detected by each detector 12A to 12D and time. The graphs Gxa and Gxb shown in FIG. 9 show the relationship between the thermal conductivity detected by the detectors 12A and 12B and time, and the graphs Gya and Gyb show the relationship between the thermal conductivity detected by the detectors 12C and 12D and time. Show. That is, it is a graph showing a change in thermal conductivity with time from time T0 when a droplet adheres to the sheet material SH. The thermal conductivity (reference thermal conductivity) at time T0 is defined as HA, the thermal conductivity 10% higher than this thermal conductivity HA is defined as HB, and the time when the thermal conductivity is HB is defined as T1. In addition, the vertical axis | shaft of the graph shown in FIG. 9 shows heat conductivity [W / mK], and a horizontal axis shows time (second).

  As shown in FIG. 9, when the droplet is attached to the sheet material SH at time T0, the moisture or solvent component of the attached droplet starts to penetrate into the sheet material SH, and the attachment center of the droplet From the inside of the sheet material SH and in the X and Y directions. Then, when the permeation reaches the lower surface opening of the package 201 of the detectors 12A to 12D, the moisture or the like penetrates the surface of the sheet material SH, and the moisture or the like passes through the moisture permeable film 210 to enter the package 201. Are diffused into the gas in the space 201A.

  Due to the diffusion of moisture and the like, the thermal conductivity of the gas in the space 201A increases, and this increase is detected by the detectors 12A to 12D.

  That is, as shown in FIGS. 2 and 3, each of the detectors 12 </ b> A to 12 </ b> D, when the droplet Q is dropped on the dropping position P <b> 1 on the sheet material SH, from the dropping position P <b> 1 to the predetermined position P <b> 2 of the sheet material SH. It will detect that it has penetrated to the position.

  In step 18, the change time t2x until the thermal conductivity reaches HB and the change time t2y are compared, and the direction with the smaller value is determined as the fiber direction. In this embodiment, as shown in FIG. 9, since t2xa <t2yb and t2xb <t2ya, t2x = t2xa + t2xb <t2y = t2ya + t2yb. Therefore, it is determined that the fiber direction of the sheet material SH is the X direction. And the control part 17 calculates | requires the sizing degree of the sheet | seat material SH based on the table F1 (refer FIG. 5) stored in the memory | storage part 13 from change time t2x.

  In step 19, image processing conditions or drying conditions are set based on the relationship between the sizing degree of the sheet material SH and the image forming conditions or drying conditions. Note that the processing in steps 11 to 18 is a sheet material size detection process, and the processing in step 19 is an image forming condition setting process and a drying condition setting process.

  That is, the image forming condition control unit 15 determines the image forming conditions such as the amount and size of droplets based on the table F2 shown in FIG. 6 stored in the storage unit 13 based on the size of the sheet material SH. 100 image forming conditions are set. Thereby, the image quality of the image formed by the image forming apparatus 100 can be improved.

  The drying condition control unit 16 obtains the heat history amount of the drying process based on the table F3 stored in the storage unit 13 from the sizing degree of the sheet material SH. For example, drying conditions such as temperature, air volume, and conveyance speed are set as drying conditions for the image forming apparatus 100. Accordingly, it is possible to stabilize the drying of the image formed by the image forming apparatus 100, and it is possible to prevent image quality deterioration due to picking.

  Incidentally, as shown in FIG. 3, the sensor chips 202A, 202B, 202C, and 202D of the detectors 12A, 12B, 12C, and 12D have the same predetermined distance L1 set in advance from the droplet attachment point P1 (see FIG. 2). They are arranged at positions separated from each other. Accordingly, if the planar shape of the droplet Q attached to the sheet material SH is substantially circular and the center of the droplet Q coincides with the droplet attachment point P1, the sizing degree of the sheet material SH is in the X direction. = T2xb <t2ya = t2yb.

  However, as shown in FIG. 9, t2xa <t2xb, t2xb> t2yb, and t2ya> t2yb. This means that the center of the droplet Q attached to the sheet material SH is shifted in the detector 12A direction and the detector 12D direction with respect to the predetermined dropping position P1.

  Thus, even when the center of the droplet Q attached to the sheet material SH deviates from the predetermined dropping position P1, the sizing degree detection device 10 of this embodiment accurately determines the sizing degree of the sheet material SH. Can be detected. This is because the control unit 17 of the sizing degree detection device 10 adds the change times t2 for each of the two directions X and Y, calculates t2x = t2xa + t2xb, t2y = t2ya + t2yb, and uses the total value of t2x and t2y. It is.

  Moreover, since each sensor chip 12SA-12SD is arrange | positioned in the space part 201A sealed with the package 201 and the moisture-permeable film 210, it does not receive to the influence of external gas. For this reason, it is possible to reliably detect that the moisture of the droplet Q has penetrated to a predetermined position of the sheet material SH, and there is no individual difference in the measurement result by visual observation as in the past. Moreover, the sizing degree of the sheet material SH can be accurately obtained, and the image quality of the image formed by the image forming apparatus 100 can be sufficiently improved.

  Further, as shown in FIG. 2, since the discharge unit 11 is disposed in the partition member 11H closed with the sheet material SH, moisture or the like evaporated from the droplet Q is contained in the partition member 11H. Will be fastened. For this reason, it is possible to prevent moisture evaporated from the droplet Q from entering the packages 201 of the detectors 12A to 12D, and to detect the sizing degree of the sheet material SH more accurately.

In this first embodiment, the droplet Q uses water or a transparent liquid, but the ink of the ink cartridge 106 may be used. In this case, the sizing degree is obtained by using a part of the image to be formed, and the image forming conditions and the drying conditions are adjusted while printing.
[Other examples]
FIG. 10 shows an image forming apparatus 150 in which the detection head 10 </ b> H of the sizing degree detection apparatus 10 is arranged in the vicinity of the paper feed mechanism 120. According to the image forming apparatus 150, the image forming conditions and the drying conditions can be corrected for each sheet material SH by measuring the sizing degree of the sheet material SH before printing.

FIG. 11 shows a sheet feeding unit of an image forming apparatus 160 provided with a plurality of sheet feeding trays 161 (only one is shown) for storing sheet materials SH having different sizes. In this image forming apparatus 160, detection heads 10H are provided in the vicinity of each pair of paper feed rollers 162 (only one set is shown), and the respective sizing degrees of sheet materials SH having different sizes are obtained. It is. The image forming apparatus 160 also measures the size of the sheet material SH before printing.
[Second Embodiment]
12 and 12A show the detection head 310 of the second embodiment. In this detection head 310, four sensor chips 12SA to 12SD are arranged in one space portion 314 formed by the package 313 to constitute one detection portion 312. The package 313 is attached to the lower surface of the circuit board 200, has an upper wall portion 313A and a peripheral wall portion 313B, and the lower surface is opened.

  The lower surface of the package 313 is covered with a moisture permeable film 210 except for the lower surface of the cylindrical partition member 315 surrounding the discharge unit 11. Reference numeral 317 denotes a cylindrical holding member that surrounds the partition member 315, and holds the moisture permeable membrane 210.

  In the detection unit 312 of the second embodiment, four sensor chips 12SA to 12SD are arranged in one space part 314 formed by the package 313, so that the detection part 312 bleeds outward from the peripheral wall part 315s of the partition member 315. The water that comes out can be detected reliably. And it can detect, without receiving to the influence of the difference in the penetration speed by the difference in the fiber direction of the sheet | seat material SH.

In the second embodiment, no stand is provided outside the peripheral wall portion 313B of the package 313, but a stand 250 may be provided as shown in FIG.
[Third embodiment]
13 and 14 show the detection head 410 of the third embodiment. The detection head 410 includes a discharge unit 11 and a detection unit 412, and the detection unit 412 includes a single detector 420.

  The detector 420 includes a package (partition forming member) 421 attached to the lower surface of the circuit board 200, a sensor chip 422 provided in the package 421, and the like. Since the package 421 and the sensor chip 422 have the same configuration as the package 201 and the sensor chip 12SA of the first embodiment, description thereof is omitted. Reference numeral 251 denotes a table similar to the table 250.

The detection unit 412 of the detection head 410 according to the third embodiment is inexpensive because one detector 420 detects the thermal conductivity.
[Fourth embodiment]
15 and 16 show a detection head 510 of the fourth embodiment. The detection head 510 according to the fourth embodiment includes a detector 520 as one detection unit 512 and two ejection units 511 and 511 provided on both sides thereof.

  The detector 520 includes a package (partition forming member) 521 attached to the lower surface of the circuit board 200, a sensor chip 522 provided in the package 521, and the like. Since the package 521 and the sensor chip 522 have the same configuration as the package 201 and the sensor chip 12SA of the first embodiment, the description thereof is omitted.

  In the detection head 510 of the fourth embodiment, it is necessary to simultaneously drop droplets from the two ejection portions 511.

According to the fourth embodiment, the sizing degree can be obtained regardless of the fiber direction in the X direction or the Y direction.
[Fifth embodiment]
FIG. 17 shows a detection head 610 of the fifth embodiment. The detection head 610 of the fifth embodiment is provided with one detection unit 612 and four ejection units 611 (not shown) around the detection unit 612. The discharge part 611 has the same configuration as the discharge part 11 of the first embodiment.

  The detection unit 612 includes a package (partition forming member) 621 attached to the lower surface of the circuit board 200, a sensor chip 622 provided in the package 621, and the like. Since the package 621 and the sensor chip 622 have the same configuration as the package 201 and the sensor chip 12SA of the first embodiment, description thereof is omitted.

  The detection head 610 of the fifth embodiment also needs to drop droplets simultaneously from the four ejection portions 611.

According to the fifth embodiment, the sizing degree can be obtained regardless of the fiber direction.
[Sixth embodiment]
18 and 19 show a detection head 710 of the sixth embodiment. This detection head 710 is composed of one ejection part 11 and four detectors 712A to 712D, and the ejection part 711 is surrounded by a peripheral wall 721C of a package 721 of the detectors 712A to 712D. Reference numeral 722 denotes a sensor chip, and the discharge unit 711, the sensor chip 722, the package 721, and the like are the same as those in the first embodiment, and a description thereof will be omitted.
[Seventh embodiment]
20 and 21 show a detection head 810 of the seventh embodiment. This detection head 810 uses a package 821 in which only a portion 821a on the opposite surface of the sensor chip 822 is opened, and a hatched portion 821b shown in FIG. 21 is closed.

This is because the influence of disturbance is reduced by reducing the opening. Since other configurations are the same as those of the first embodiment, description thereof is omitted.
[Eighth embodiment]
FIG. 22 shows a detection head 910 of the eighth embodiment. The detection head 910 includes an absorption member 912 that absorbs moisture, such as a sponge, provided at the tip of the discharge unit 911, an elevating unit 920 that moves the discharge unit 911 up and down, and a gas at a predetermined position on the sheet material SH. And a detecting unit 12 for detecting the thermal conductivity of the. The detection unit 12 includes four detectors 12A to 12D (see FIG. 3).

  The detection head 910 causes the discharge unit 911 to be lowered by the lifting / lowering means 920 to bring the absorbing member 912 into contact with the sheet material SH and attach the liquid to the sheet material SH. Then, the thermal conductivity is detected by the detectors 12A to 12D in the same manner as in the first embodiment, and the sizing degree of the sheet material SH is obtained. In addition, after the liquid is attached to the sheet material SH, the discharge unit 911 is raised by the lifting / lowering means 920.

  The detection head 910 of the eighth embodiment is provided with the detection unit 12, but instead of the detection unit 12, any of the detection units 310 to 710 of the second to seventh examples is provided. Also good.

  In any of the above embodiments, the discharge unit 11 and the sensor chips 12SA to 12SD and 422 to 822 are surrounded by the partition member 11H and the packages 201 to 821, but if the influence of the disturbance is small, the partition member 11H and the packages 201 to Either one or both of 821 may be omitted. Further, although the moisture permeable film 210 is stretched in the openings of the packages 201 to 821, the moisture permeable film 210 may be omitted.

  In each of the above-described embodiments, the sizing degree detection device 10 is applied to the inkjet image forming apparatus 100. However, the present invention is not limited to this. For example, the present invention can be similarly applied to other image forming apparatuses such as a copying machine, a printer, a facsimile machine, and a multifunction machine including these as an integrated unit.

  Moreover, although the thermal conductivity is detected and the sizing degree of the sheet material SH is obtained, the sizing degree of the sheet material SH may be obtained by detecting the humidity using a humidity sensor.

  The sizing degree detection method is not limited to the process executed by the sizing degree detection device 10 of FIG. 1, and is not limited to the process executed by the sizing degree detection device 10.

  As mentioned above, although the Example of this invention was described, the numerical value, material, arrangement | positioning, number, etc. in the said Example are examples, and this invention is not limited to these. Various modifications can be made within the scope of the present invention described in the claims, and design changes and additions are permitted without departing from the spirit of the invention of the claims.

10 Size detector 11 Discharge part (attachment means)
12 detector 12A-12D detector 12SA-12SD sensor chip (detection means)
17 Control unit (calculation means)
100 Image forming apparatus SH sheet material

Japanese Patent No. 4879841

Claims (9)

Attachment means for attaching droplets to the sheet material;
Detection means for detecting the thermal conductivity or humidity of the gas in the vicinity of the adhesion portion of the sheet material before and after the time point when the droplet is adhered to the sheet material by the adhesion means;
The time until the thermal conductivity or humidity after adhesion detected by the detection means changes to a predetermined ratio or more as compared to the thermal conductivity or humidity before adhesion of the droplet detected by the detection means. A sizing degree detection apparatus comprising: an arithmetic unit that obtains an elapsed time from the time and calculates a sizing degree of the sheet material based on a relationship between the elapsed time and the sizing degree of the sheet material. A closed space forming member that forms a closed space having an opening that is closed by the sheet material;
The sizing degree detection apparatus according to claim 1, wherein the adhering unit or the detecting unit is disposed in the closed space forming member.   The sizing degree detection apparatus according to claim 2, wherein the detection means is disposed in the closed space forming member, and a moisture permeable film is stretched on an opening of the closed space forming member.   The closed space forming member is disposed at a position where the adhering unit is sandwiched between the sheet material feeding direction and the width direction, and the detecting unit is disposed in the closed space forming member. The sizing degree detection device according to claim 2.   The sizing degree detection apparatus according to claim 4, wherein a moisture permeable film is stretched on the opening of the closed space forming member.   The sizing degree detection apparatus according to claim 4, wherein the attaching unit is disposed in a closed space forming member different from the closed space forming member.   An image forming apparatus comprising the sizing degree detection device according to claim 1. Attaching droplets to the sheet material;
Detecting the thermal conductivity or humidity of the gas in the vicinity of the adhesion portion of the sheet material before and after the time point when the droplet is adhered to the sheet material by this step;
Compared to the thermal conductivity or humidity before the droplet adhesion detected in this step, from the time point until the thermal conductivity or humidity after adhesion detected by the detection means changes to a predetermined ratio or more. And a step of obtaining the sizing degree of the sheet material based on a relationship between the elapsed time and the sizing degree of the sheet material.   9. At least one of the step of setting image forming conditions from the sizing degree obtained by the sizing degree detection method according to claim 8 and the step of setting drying conditions for drying the formed image based on the sizing degree. An image forming method comprising one of the steps.