JP2017030355A - Sensor device, system, image forming device, dry state detection method, output control method, transportation speed control method, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor device that can accurately detect a state of a recording medium.SOLUTION: The sensor device includes: at least one humidity sensor 40 (sensor) facing the recording medium to which a recording material adheres and detecting a state of atmosphere in the vicinity of the recording medium; and a main control part 50 (detection part) for detecting a state of the recording medium on the basis of output from the humidity sensor 40. Thus, the sensor device can accurately detect a state of the recording medium.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sensor device, a system, an image forming apparatus, a dry state detection method, an output control method, a conveyance speed control method, and an image formation method.

  Patent Document 1 discloses a technique for detecting a dry state of a recording material attached to a recording medium.

  However, the dryness detection unit including the optical sensor disclosed in Patent Document 1 determines whether or not the recording material has moved to another object by bringing another object into contact with the recording material on the recording medium that has undergone the drying process. It is optically detected, that is, used for simple picking inspection, and cannot accurately detect the state of the recording medium.

  The present invention relates to a sensor device including at least one sensor that detects the state of an atmosphere in the vicinity of a recording medium to which a recording material is attached, and a detection unit that detects the state of the recording medium based on the output of the sensor. It is.

  According to the present invention, the state of the recording medium can be detected with high accuracy.

It is a figure which shows schematic structure of the droplet discharge apparatus which concerns on one Embodiment. It is a figure for demonstrating arrangement | positioning of a humidity sensor. It is a figure for demonstrating the structure of a humidity sensor. It is a figure which shows the test pattern 1. It is a figure which shows an example of the output of a humidity sensor at the time of insufficient drying of a droplet. It is a figure which shows a mode that water vapor | steam moves at the time of insufficient drying of a droplet. It is a figure which shows an example of the output of a humidity sensor at the time of excessive drying of a droplet. It is a figure which shows a mode that water vapor | steam moves at the time of excessive drying of a droplet. It is a figure which shows an example of the output of a humidity sensor when there is no excess and deficiency in drying of a droplet. It is a figure for demonstrating the method of digitizing the dry state of a droplet. It is a block diagram which shows an example of the hardware constitutions of a droplet discharge apparatus. 6 is a flowchart for explaining an image forming method according to an embodiment; 5 is a flowchart for explaining dry output adjustment processing 1; FIG. 14A to FIG. 14D are diagrams for explaining examples (part 1 to part 4) in which a plurality of humidity sensors are arranged. It is a figure for demonstrating the example which made the position of a humidity sensor variable. It is a figure for demonstrating the test pattern 2. FIG. It is a figure for demonstrating the test pattern 3. FIG. 10 is a flowchart for explaining an image forming method according to a first modification. It is a flowchart for demonstrating the dry output adjustment process 2. FIG. 10 is a flowchart for explaining an image forming method according to a second modification. 10 is a flowchart for explaining an image forming method according to a third modification. It is a figure for demonstrating the droplet discharge apparatus of the modification 4. It is a figure for demonstrating the droplet discharge apparatus of the modification 5. FIG. It is a graph which shows the relationship between drying conditions and absolute humidity difference (A)-(B). It is a relationship figure which shows the relationship between the output of a humidity sensor, the output of a temperature sensor, and humidity. It is a flowchart for demonstrating the method of digitizing a dry state using a real image.

<Embodiment>
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a droplet discharge apparatus 100 according to an embodiment which is an example of an image forming apparatus of the present invention.

  As shown in FIG. 1, the droplet discharge device 100 includes a printing device 10, a transport unit 20, a drying unit 30, a humidity sensor 40, a control device 150 (see FIG. 11) including a main control unit 50, and the like. . The main control unit 50 includes, for example, a CPU, and comprehensively controls the above-described components of the droplet discharge device 100.

  In the following, description will be made using the XYZ three-dimensional orthogonal coordinate system shown in FIG.

  The conveyance unit 20 includes an unwinding unit 7, an unwind roller pair 8, a guide roller 15, a first touch roller 16, a rewind roller pair 18, and a winding unit 19.

  The unwinding unit 7 holds a long roll paper (recording paper) as an example of a recording medium so that it can be sent downstream (+ X side).

  The unwind roller pair 8 is arranged on the downstream side (+ X side) of the unwinding portion 7 from a driving roller 8a and a driven roller 8b that form the nip portion by contacting the outer peripheral surfaces with the Y axis direction as the axial direction. The recording medium set in the unwinding unit 7 is sent to the downstream side (+ X side) while being sandwiched by the nip portion. The drive roller 8a is controlled by the main control unit 50.

The printing unit 10 is disposed on the downstream side (+ X side) of the unwind roller pair 8 and forms an image by attaching a recording material to a recording medium. For example, the printing unit 10 includes a droplet discharge head 10a that discharges droplets made of a recording material.
Examples of the “recording material” include, but are not limited to, water-based ink, oil-based ink, heat-dissolved ink, dye ink, pigment ink, pulverized toner, polymerized toner, and wet developing toner.

  The droplet discharge head 10 a is disposed on the + Z side of the recording medium conveyance path from the unwind roller pair 8. Droplets are supplied to the droplet discharge head 10a from the droplet storage section. The droplet discharge head 10 a is controlled by the main control unit 50.

  The droplet discharge head 10a may be a carriage-mounted head that discharges droplets while scanning in the width direction of the recording medium, or a line head that discharges droplets without scanning in the width direction of the recording medium. .

  The drying unit 30 is disposed on the downstream side (+ X side) of the printing unit 10 and dries the recording medium on which an image has been formed by the printing unit 10 and has been wetted with droplets.

  As the drying unit 30, for example, a dielectric heating device, a uniform heating device, and a combination thereof are used. When these combinations are used, dielectric heating and uniform heating are performed at different timings on the recording medium.

  The dielectric heating device is a selective heating means that can select a heating target, represented by a microwave heating method, a high-frequency dielectric heating method (1 MHz to 100 MHz), and the like. That is, the dielectric heating device can dry droplets more efficiently than a general heating method by applying energy to moisture. Since the dielectric heating device generates heat by the frictional heat of the molecular vibration of the dielectric, the heat generation characteristics depend on the physical properties of the substance.

  A uniform heating device is a device that heats a recording medium wetted with droplets substantially evenly, and can be realized by a general heating method, and it can be realized by a wide-band IR radiation heating represented by hot air heating, a heat drum, and a ceramic heater. Etc.

  The guide roller 15 is disposed on the downstream side (+ X side) of the drying unit 30 and guides the recording medium dried by the drying unit 30 toward the first touch roller 16 (to the −Z side).

The humidity sensor 40 is disposed in the vicinity of the conveyance path of the recording medium between the drying unit 30 and the guide roller 15 (see FIG. 1), and detects the state of the atmosphere in the vicinity of the recording medium from which the image has been dried by the drying unit 30. To do.
“Ambient state in the vicinity of the recording medium” refers to the absolute humidity, relative humidity, dew point, wet bulb temperature, thermal conductivity, thermal conductivity, etc. of the air (gas) in the vicinity of the recording medium.

Here, the humidity sensor 40 is disposed to face the center in the width direction of the conveyance path of the recording medium (see FIG. 2). The humidity sensor 40 and the main control unit 50 constitute a “sensor device” that detects the state of the recording medium.
“Recording medium state” means the dry state of the droplets on the recording medium, and uses indicators such as the impregnation degree, fixing degree, penetration degree, height, stability, and elasticity of the droplets on the recording medium. Detected. Details of the humidity sensor 40 will be described later.
Further, the humidity sensor 40 is preferably disposed on the surface side of the recording medium opposite to the surface on which the recording material adheres as shown in FIG. 1, but the present invention is not limited to this, and for example, the shape of the recording medium The installation position may be changed as appropriate based on the properties and the like.
Furthermore, in order to stabilize the interval between the humidity sensor 40 and the recording medium, for example, it is preferable that the humidity sensor 40 be installed in the vicinity of another constituent member in the vicinity of the conveyance path of the recording medium or be configured integrally with the other constituent members. In the example of FIG. 1, the humidity sensor 40 is installed in the vicinity of the guide roller 15 which is another constituent member.

  The first touch roller 16 is disposed downstream of the guide roller 15 (on the + X side and the −Z side obliquely below).

  The rewind roller pair 18 is disposed on the downstream side of the first touch roller 16 (on the + X side and the + Z side obliquely above). And the driven roller 18b, and the recording medium dried by the drying unit 30 is conveyed to the downstream side while being sandwiched by the nip portion. The driving roller 18a is controlled by the main control unit 50.

  The winding unit 19 is disposed on the downstream side (+ X side) of the rewind roller pair 18 and winds the recording medium sent from the rewind roller pair 18.

  When the main control unit 50 receives a print request from a host device (for example, a personal computer), the two control rollers 8a and 18a are synchronously driven to feed the recording medium from the upstream side to the downstream side, and the droplet discharge head 10a is moved. Drive to form an image on the recording medium, and after the portion of the recording medium on which the image has been formed is dried by the drying unit 30, the output change of the humidity sensor 40 with respect to the dried portion of the recording medium is acquired. . The main control unit 50 generates a drive signal for the droplet discharge head 10a based on image data from a host device (for example, a personal computer).

  Hereinafter, the humidity sensor 40 will be described in detail. FIG. 3 shows an XZ sectional view of the humidity sensor 40. The humidity sensor 40 is a heat conduction type humidity sensor and detects the state of the nearby atmosphere. The humidity sensor 40 includes a sensor package 51, a sensor device case 60, a moisture permeable film 75, a flexible substrate 81, a lid 82, a humidity detection chip 52, and a wire 53.

  The flexible substrate 81 and the sensor package 51 are joined to each other. The sensor package 51 is hollow, and the humidity detection chip 52 is bonded to the inside of the upper wall of the sensor package 51.

  The humidity detection chip 52 and the sensor package 51 are electrically connected by a wire 53. The wire 53 is provided so as not to exit from the opening of the sensor package 51.

  The sensor package 51 has wiring that electrically connects the wire 53 and the flexible substrate 81. An opening is provided on the lower surface of the sensor package 51. The sensor package 51 is disposed such that the lower surface of the sensor package 51 is below the bottom surface 60 a of the recess 61.

  The sensor device case 60 can fix the sensor device case 60 to the guide plate 46. The moisture permeable film 75 has a circular shape or an elliptical shape, and the sensor package 51 has a square shape or a rectangular shape. The sensor package 51 has a square shape with a side length of 3 mm, for example.

  A recess 61 is provided on the upper surface of the sensor device case 60, and an opening 63 that penetrates in the thickness direction of the sensor device case 60 is provided at the center of the recess 61. The opening 63 has a shape having a circular shape at four corners of a square. The size of the opening 63 is provided so as to be larger than the sensor package 51, and the sensor package 51 is disposed at the center of the opening 63.

  An opening 83 is provided at the center of the lid 82. The lid 82 is fixed to the sensor device case 60 by inserting the left and right ends of the lid 82 into pockets provided in the sensor device case 60.

  The sensor device case 60 is made of polyvinyl chloride having thermoplasticity, and the moisture permeable membrane 75 is made of PTFE (polytetrafluoroethylene) having extensibility and porosity. The moisture permeable film 75 transmits water vapor as gas but does not allow liquid water to pass through. The thickness of the moisture permeable membrane 75 is, for example, 0.3 mm.

  The moisture permeable film 75 is joined to the bottom surface 60a of the recess 61 (a surface on the inner side of the sensor device case 60 opposite to the opening 63) in the welding portion 70a by a thermal welding method. . Further, the moisture permeable film 75 is provided so as to close the opening of the sensor package 51.

  The humidity detection chip 52 generates a signal having a signal level corresponding to the absolute humidity of the air in the sensor package 51, and outputs the signal to the flexible substrate 81 through the wire 53 and the wiring in the sensor package 51. The humidity detection chip 52 can be realized by, for example, a humidity sensor disclosed in Japanese Patent No. 3460749. The humidity detection chip 52 is formed using MEMS (Micro Electro Mechanical System) technology.

  The lid 82 is disposed so as to push the flexible substrate 81 and the sensor package 51 into the sensor device case 60. Accordingly, the flexible substrate 81 is provided so as to sandwich the moisture permeable film 75 with respect to the bottom surface 60a to which the moisture permeable film 75 is bonded. Further, the height of the sensor device case 60 and the depth of the recess 61 are set so that there is no step between the lower surface of the moisture permeable membrane 75 and the lower surface of the sensor device case 60.

  The humidity sensor 40 is fixed to a guide plate 46 disposed in the vicinity of the + Z side of the recording medium conveyance path. Since the humidity detection chip 52 is manufactured using the MEMS technology, the humidity detection chip 52 can be reduced to a size of several millimeters. As a result, the entire size of the humidity sensor 40 can also be reduced. Therefore, the humidity sensor 40 can be installed in a relatively narrow space.

  In FIG. 3, the guide plate 46 has an opening that penetrates in the thickness direction. The humidity sensor 40 is fixed to the guide plate 46 so that the lower part of the humidity sensor 40 is stored in the opening of the guide plate 46.

  The sensor device case 60 and the guide plate 46 are formed so that there is no step between the lower surface of the humidity sensor 40 and the lower surface of the guide plate 46 when the humidity sensor 40 is fixed to the guide plate 46. By fixing the humidity sensor 40 to the guide plate 46 in this manner, the humidity sensor 40 is disposed in the vicinity of the recording medium to be conveyed and separated from the recording medium by a certain distance.

  As described above, the humidity sensor 40 is disposed in the vicinity of the conveyance path of the recording medium between the drying unit 30 and the guide roller 15 that is a roller that first touches the recording medium after drying the droplets by the drying unit 30. . The droplets on the recording medium to which energy is given by the drying unit 30 are also dried while the recording medium moves in the conveyance section from the drying unit 30 to the humidity sensor 40. Note that the liquid droplets ejected to the recording medium by the printing unit 10 are also dried while the recording medium moves in the transport section from the printing unit 10 to the drying unit 30.

  By disposing the humidity sensor 40 in the vicinity of the recording medium as described above, the absolute humidity of the air in the sensor package 51 becomes substantially equal to the absolute humidity of the air in the vicinity of the recording medium. The absolute humidity of nearby air can be detected. Note that the closer the humidity sensor 40 is to the recording medium, the more accurate the humidity sensor 40 can detect the absolute humidity of the air near the recording medium.

  If the lower surface of the moisture permeable film 75 protrudes below the lower surface of the sensor device case 60, the moisture permeable film 75 may be worn due to contact with the recording medium to which the moisture permeable film 75 is conveyed several times. is there. Further, when the lower surface of the moisture permeable film 75 is above the lower surface of the sensor device case 60, foreign matters such as paper dust generated from the recording medium are deposited on the lower surface of the moisture permeable film 75. There is a possibility that the output is reduced and the response of the humidity detection chip 52 is delayed. Therefore, as described above, the humidity sensor 40 is provided such that there is no step between the lower surface of the moisture permeable film 75 and the lower surface of the sensor device case 60.

  FIG. 4 is a schematic diagram of the test pattern 1 (test image) printed on the recording medium by the printing unit 10. In this test pattern 1, image portions (portions where images are formed) and non-image portions (portions where images are not formed) are alternately arranged along the direction in which the recording medium moves (conveyance direction). Accordingly, it is possible to detect the dry state at a plurality of locations in the length direction (longitudinal direction) of the recording medium with one humidity sensor 40.

  FIG. 5 shows an example of the output of the humidity sensor 40 when the droplets are insufficiently dried. In FIG. 5, the horizontal axis represents elapsed time, and the vertical axis represents the output (absolute humidity) of the humidity sensor 40. Here, as the test pattern 1, a pattern in which six image portions are formed along the conveyance direction of the recording medium is used.

  When the image portion of the test pattern 1 reaches the position facing the humidity sensor 40 when the droplet is insufficiently dried, water vapor diffused from the droplet of the image portion into the air passes through the recording medium, and the humidity sensor 40 The thermal conductivity and humidity of the nearby air increase (see FIG. 5). FIG. 6 shows how water vapor moves when the droplets are insufficiently dried.

  When the image portion passes the position facing the humidity sensor 40 and the non-image portion reaches the position, the thermal conductivity and humidity of the air near the humidity sensor 40 are lowered.

  FIG. 7 shows an example of the output of the humidity sensor 40 when the droplets are excessively dried. In FIG. 7, the horizontal axis represents elapsed time, and the vertical axis represents the output (absolute humidity) of the humidity sensor 40. Here, as the test pattern 1, a pattern in which six image portions are formed along the conveyance direction of the recording medium is used.

  Droplets dried by applying excessive energy absorb moisture from nearby air after the peak of drying, resulting in low thermal conductivity and humidity of the air.

  When the image portion of the test pattern 1 reaches the position facing the humidity sensor 40 when the droplet is excessively dried, the droplet in the image portion absorbs moisture from the nearby air, and the air near the humidity sensor 40 Thermal conductivity and humidity are reduced.

  When the image portion passes a position facing the humidity sensor 40 and a non-image portion reaches the position, the thermal conductivity and humidity of the air near the humidity sensor 40 increase. FIG. 8 shows how the water vapor moves when the droplets are excessively dried.

  That is, in the droplet discharge device 100, when the drying is insufficient, the moisture diffuses from the droplet and permeates the recording medium, and the thermal conductivity and humidity of the air near the humidity sensor 40 increase. Conversely, when the drying is excessive, the droplets absorb moisture from the atmosphere, and the thermal conductivity and humidity of the air near the humidity sensor 40 are lowered.

  FIG. 9 shows an example of the output of the humidity sensor 40 when there is no excess or deficiency in drying the droplets. In FIG. 9, the horizontal axis represents elapsed time, and the vertical axis represents the output (absolute humidity) of the humidity sensor 40. Here, as the test pattern 1, a pattern in which six image portions are formed along the conveyance direction of the recording medium is used.

  In FIG. 9, there is no significant difference between the humidity in the vicinity of the image portion where the droplet is attached to the recording medium as shown in FIGS. 5 and 7 and the non-image portion where the droplet is not attached. It turns out that it has dried without lack.

  Here, as can be seen from the output examples of the humidity sensor 40 in FIGS. 5, 7, and 9, the output of the humidity sensor 40 is changed from the value when the image portion is opposed to the humidity sensor 40 to the original value ( The time required to return to the value when the image portion is not facing is 1 to 1.5 times as long as the time when the image portion is facing.

  Therefore, in the test pattern 1 of FIG. 4, the length of the image portion in the transport direction (direction parallel to the transport path) and the length of the non-image portion in the transport direction (direction parallel to the transport path) are greater in the non-image portion. The length longer than the image portion is preferable, and the length of the entire test pattern 1 in the transport direction is preferably as short as possible. It is preferable to set the ratio of the length of the image portion in the transport direction and the length of the non-image portion in the transport direction to 1: (1 to 1.5).

  Hereinafter, a method for quantifying the dry state of droplets will be described with reference to FIG. Note that the case of insufficient drying shown in FIG. 10 will be described as an example, but the same description holds even when the drying is excessive. Here, as the test pattern 1, a pattern in which n image portions are formed at equal intervals along the conveyance direction of the recording medium is used.

  First, an average value (A) of absolute humidity in a section including five image portions in the test pattern 1 is obtained. Next, the absolute humidity serving as a reference value is obtained. Specifically, an average value of absolute humidity for 0.6 seconds immediately before the second to fifth image portions is set as a reference value (B). In addition, although the example which uses an average value for (A) and (B) is demonstrated here, it is not restricted to this. For example, the sum of absolute humidity in the section including the five image portions may be (A), or the sum of absolute humidity for 0.6 seconds immediately before the second to fifth image portions may be (B). Also good.

The difference between the average value (A) and the reference value (B) is used as an indicator of the dry state. As an example showing the difference in the dry state, FIG. 24 shows a graph of the relationship between the dry condition and the absolute humidity difference (A)-(B). When the absolute humidity difference AB is larger than 0.5 g / m ^3, drying is insufficient. In FIG. 24, the value of the absolute humidity difference (A)-(B) decreases as the energy applied to the recording medium under the drying conditions increases, and when the value is smaller than 0.5 g / m ³ , it can be sufficiently dried. Yes. When the energy applied to the recording medium is further increased, the absolute humidity difference (A)-(B) becomes negative. This indicates that after the recording medium releases moisture at a position facing the drying unit 30, it absorbs moisture in the air when it deviates from the position.

  FIG. 11 is a block diagram illustrating a hardware configuration of the droplet discharge device 100.

  In addition to the printing unit 10, the conveyance unit 20, the drying unit 30, the humidity sensor 40, and the main control unit 50, the droplet discharge device 100 includes an environment information measurement unit 65 and a storage unit 70 as shown in FIG. (Memory or hard disk), a timer unit 80 (timer), an image forming condition control unit 90, a transport condition control unit 110, and a drying condition control unit 120 are provided.

  Each of the components is connected to be communicable via a bus line. The control device 150 includes the main control unit 50, the storage unit 70, the time measuring unit 80, the image forming condition control unit 90, the transport condition control unit 110, and the drying condition control unit 120.

  The image forming condition control unit 90 controls the concentration (moisture content) of droplets ejected from the droplet ejection head 10a of the printing unit 10, for example. Specifically, a plurality of droplet storage portions that store droplets having different moisture contents may be provided so as to be selectively connectable to the droplet discharge head 10a. Further, a configuration in which the discharge amount of the droplets discharged from the droplet discharge head 10a is simply increased or decreased may be employed.

  The conveyance condition control unit 110 controls, for example, the conveyance speed of the recording medium by the conveyance unit 20. Specifically, the linear speed of the drive rollers 8a and 18a is controlled.

  The drying condition control unit 120 controls the drying output that is the output of the drying unit 30. Specifically, the power supplied to at least one drying unit included in the drying unit 30 is controlled.

  Here, it is preferable to obtain a dry state by the method described with reference to FIG.

  Specifically, when the drying is insufficient, the drying output is increased, the conveyance speed is decreased, or the moisture content of the droplet is decreased. On the other hand, when the drying is excessive, the drying output is lowered, the conveying speed is increased, or the moisture content of the droplet is increased.

  As a result, picking due to insufficient drying can be suppressed, and furthermore, the recording medium can be dried uniformly, so that cockling (waving) can be reduced.

The environmental information measurement unit 65 measures at least one of ambient temperature, humidity, and atmospheric pressure, for example. The drying speed of the droplets is greatly influenced by the water vapor pressure, which is strongly temperature dependent. When measuring the thermal conductivity of a gas, fluctuations in the atmospheric pressure can cause an error. Therefore, it is necessary to take into consideration when measuring the thermal conductivity humidity sensor to correct the drying conditions. Specifically, with respect to the voltage output of the humidity sensor 40, the output of the humidity sensor 40 under the standard atmospheric pressure condition is obtained from the relational expression between the voltage output of the humidity sensor 40 and the atmospheric pressure obtained in advance. The standard atmospheric pressure is 1013.25 hPa. Further, the humidity is calculated from the relational expression of the humidity sensor output, the temperature sensor output and the humidity shown in FIG. Here, “humidity” means absolute humidity [g / m ³ ], relative humidity [%], dew point [° C.], or wet bulb temperature [° C.].

  Hereinafter, an image forming method using the droplet discharge device 100 of the present embodiment will be described with reference to FIG. The flowchart in FIG. 12 is based on a processing algorithm executed by the main control unit 50. This flow is started when the main control unit 50 receives a job start request from a host device (for example, a personal computer).

  In the first step S1, “dry output adjustment processing 1” is performed. The dry output adjustment process 1 will be described later.

  In the next step S3, an image is formed on the recording medium. Specifically, the droplet discharge head 10a is controlled to discharge droplets onto the recording medium based on the image information.

  In the next step S5, the image is dried with the set drying output. Specifically, the drying unit 30 is controlled via the drying condition control unit 120 so that the drying output that is initially set or adjusted in the drying output adjustment processing 1 is obtained.

  In the next step S7, it is determined whether or not the job is finished. If the determination here is affirmed, the process proceeds to step S9. If the determination is negative, the process returns to step S3.

  In step S9, the conveyance of the recording medium is stopped. When step S9 is executed, the flow ends.

  Next, the dry output adjustment processing 1 will be described with reference to FIG. The flowchart in FIG. 13 is based on a processing algorithm executed by the main control unit 50. Here, initially, the drying output of the drying unit 30 is set to a standard value, for example. This “standard value” is a theoretical calculation value that allows the recording medium to be dried without excess or deficiency in accordance with the moisture content of the droplets discharged onto the recording medium and the conveyance speed (drying time) of the recording medium.

  In the first step T1, conveyance of the recording medium is started. Specifically, the conveyance unit 20 is controlled to send the recording medium from the upstream side to the downstream side of the conveyance path.

  In the next step T3, test pattern 1 (see FIG. 4) is formed on the recording medium. Specifically, the droplet discharge head 10a is controlled to discharge droplets onto the recording medium based on the image information of the test pattern. Note that the test pattern image information is stored in the storage unit 70 in advance.

  In the next step T5, the test pattern 1 is dried. Specifically, the test pattern 1 formed on the recording medium is dried by the drying unit 30 while the drying output is kept at the original value (for example, the default standard value).

  In the next step T7, the state of the atmosphere in the vicinity of the recording medium is detected. Specifically, an output signal of the humidity sensor 40 is acquired while the test pattern 1 passes through a position facing the humidity sensor 40.

  In the next step T9, time t1 is calculated. The time t1 is the sum of a value obtained by dividing the distance L by which the recording medium is fed from the unwind roller pair 8 to the printing unit 10 by the conveyance speed V of the recording medium and the droplet discharge time t0 in the printing unit 10.

  In the next step T11, an average value (A) of absolute humidity over a predetermined time including n image portions after t1 is obtained.

  In the next step T13, an absolute humidity serving as a reference value is obtained. Specifically, an average value immediately before each image portion (for example, 0.6 seconds) is set as a reference value (B). The timing for obtaining the reference value (B) is not limited to step T13, and may be before step T3 or after step T7.

  In the next step T15, the dry state of the test pattern 1 is obtained. Specifically, “the average value (A) −the reference value (B)” is set to a dry state.

  In the next step T17, it is determined whether or not the drying is insufficient. Specifically, when the dry state of the obtained test pattern 1 is negative and the absolute value thereof is equal to or greater than the threshold value Dth, it is determined that the drying is insufficient, and in other cases, it is determined that the drying is not insufficient. If the determination here is affirmed, the process proceeds to step T19. If the determination is negative, the process proceeds to step T21.

  In step T19, the drying output is increased. Here, the change in the dry state with respect to the change in the dry output is acquired in advance, and a table representing the correspondence between the dry output and the dry state is stored in the storage unit 70. Therefore, the main control unit 50 refers to this table and raises the drying output from the original value (eg, the standard value) so that the absolute value of the drying state is less than the threshold value Dth. When step T19 is executed, the flow ends.

  In step T21, it is determined whether or not there is excessive drying. Specifically, when the obtained dry state of the test pattern 1 is positive and the absolute value thereof is equal to or greater than the threshold value Dth, it is determined that there is excessive drying, and in other cases, it is determined that there is no excessive drying. If the determination here is affirmed, the process proceeds to step T23, and if the determination is negative, the flow ends.

  In step T23, the drying output is lowered. Here, the main control unit 50 refers to the above table and lowers the drying output from the original value (for example, the standard value) so that the absolute value of the drying state is less than the threshold value Dth. When step T23 is executed, the flow ends.

  As can be understood from the above description, in this embodiment, the dry state of the test pattern 1 is obtained for each job, and the dry output is adjusted according to the dry state, so that the image can be appropriately dried for each job. .

  The sensor device according to the present embodiment described above has a humidity sensor 40 (sensor) that detects the state of the atmosphere in the vicinity of the recording medium on which the droplet is attached and is transported, and the drying of the droplet based on the output of the humidity sensor 40. A main control unit 50 (detection unit) for detecting a state. In this case, the output of the humidity sensor 40 faithfully (accurately) reflects the dry state of the droplets. As a result, the state of the recording medium can be detected with high accuracy.

  Further, since the recording medium is transported on a transport path including a position at which droplets are ejected and a position facing the humidity sensor 40, an image is formed on the recording medium while the recording medium is transported, and the image is dried. In the image forming process to be performed, the dry state of the droplets can be accurately detected.

  Furthermore, the humidity sensor 40, which is a heat-conducting humidity sensor, can measure the humidity, more precisely the thermal conductivity of air, much faster than other types of humidity sensors. It is possible to quickly determine whether the environment is damp or dry. More specifically, when the droplets discharged onto the recording medium are not sufficiently dried, the water vapor moves from the recording medium to the outside air, and when the drying is excessive, the water vapor moves from the outside air to the recording medium. It is possible to accurately measure the dry state of the discharged droplets.

  On the other hand, the dryness detection unit including the optical sensor disclosed in Patent Document 1 optically detects whether or not the ink has moved to the object by bringing another object into contact with the printing unit that has undergone the drying process, that is, simple. It is used for typical picking inspection, and the state of the recording medium cannot be detected with high accuracy.

  Further, since the humidity sensor 40 faces the surface opposite to the surface on which the droplets of the recording medium are ejected, it can suppress the recording surface of the recording medium from being stained or damaged.

  In addition, the sensor device, the transport unit 20 that transports the recording medium on the transport path, and the droplet on the recording medium positioned on the transport path between the position where the droplet is discharged and the position facing the humidity sensor 40 In the droplet drying system including the drying unit 30 for drying, the drying state of the droplets after drying by the drying unit 30 can be accurately detected.

  In addition, since the droplet drying system further includes control means including a main control unit 50 and a drying condition control unit 120 that control the drying state of the droplets based on the drying state obtained by the sensor device. The drying state of the droplets can be controlled with high accuracy, and as a result, the droplets can be dried without excess or deficiency.

  Further, since the control unit controls the drying unit 30 based on the dry state obtained by the sensor device, the dry state of the droplets can be accurately controlled.

  Also, a droplet discharge device 100 (image forming unit) including a droplet drying system and a printing unit 10 (image forming unit) that forms an image by discharging droplets onto a recording medium located at a position where droplets are discharged. In the forming apparatus, it is possible to obtain a recorded image (printed image) in which the image is dried without excess or deficiency.

  In addition, since the printing unit 10 forms a test pattern for determining the dry state of the droplet on the recording medium, the dry state of the droplet can be detected with higher accuracy.

  The dry state detection method of the present embodiment also includes a step of detecting the state of the atmosphere in the vicinity of the recording medium to which the droplets are attached and conveyed, and the dry state of the droplets based on the detection result in the detecting step. Detecting.

  In this case, the detection result in the detecting step faithfully reflects the dry state of the droplet (with high accuracy). As a result, the dry state of the droplet can be detected with high accuracy.

  Further, the dry output control method of the present embodiment is a dry output control method for controlling the output of the drying unit 30 that dries droplets ejected onto a recording medium conveyed on a predetermined conveyance path. Recording is performed on the basis of the detection result in the step of drying the discharged droplets in the drying unit 30, the step of detecting the state of the atmosphere in the vicinity of the recording medium in which the droplets are dried in the drying unit 30, and the detection step. A step of detecting the state of the medium, and a step of adjusting the output (drying output) of the drying unit 30 based on the state of the recording medium. In this case, the liquid droplets discharged onto the recording medium can be dried without excess or deficiency.

  Further, the image forming method of the present embodiment includes a step of forming an image by ejecting liquid droplets onto a recording medium located in a first area on a predetermined transport path, and a first recording medium on which the image is formed. A step of transporting the image from the first region to the second region on the transport path, a step of drying the image on the recording medium positioned in the second region by the drying unit 30, and a step of drying the recording medium on which the image has been dried A step of conveying from the region to a third region on the conveyance path, a step of detecting the state of the atmosphere in the vicinity of the recording medium located in the third region, and the state of the recording medium based on the detection result in the step of detecting Detecting the image, adjusting the output of the drying unit 30 based on the state of the recording medium, forming an image by discharging droplets to another recording medium located in the first area, Another recording medium on which the image is formed is carried from the first area to the second area. And a step of a step of drying in the drying unit 30 for outputting an image on another recording medium is adjusted to a position in the region of the second, the. In this case, a high quality image can be formed on the recording medium.

  As shown in FIG. 14A, a plurality of humidity sensors 40 may be arranged in a direction (Y-axis direction) perpendicular to the conveyance direction of the recording medium. In the example of FIG. 14A, the humidity sensor 40 is 1 at a total of three positions: two positions corresponding to (opposing) both ends of the recording medium in the width direction and one position corresponding to (opposite) the center in the width direction. It is arranged one by one.

  In this case, the dry state of the recording medium can be obtained over a wide range with respect to the Y-axis direction. Therefore, in order to obtain the dry state of many portions of the recording medium, more (four or more) humidity sensors 40 may be arranged in the Y-axis direction than in the example of FIG. The arrangement direction of the plurality of humidity sensors 40 is not limited to the Y-axis direction, but may be any direction that is not parallel to the recording medium conveyance direction.

  In the example of FIG. 14B, the positions of a plurality of (for example, two) humidity sensors 40 are positions corresponding to one side and the other side of the recording medium in the Y-axis direction, respectively. When it is estimated that the energy applied to the recording medium by the drying unit 30 is sufficient in the central part of the recording medium and each side part is insufficient, the humidity sensor 40 corresponding to the central part of the recording medium is omitted. Thus, it is only necessary to provide one humidity sensor 40 corresponding to each side portion.

  In the example of FIG. 14C, the positions of a plurality of (for example, two) humidity sensors 40 are positions corresponding to the central portion and one side portion of the recording medium in the Y-axis direction, respectively. When correcting the conditions of the drying unit 30 so that the dry state of the central portion and one side portion of the recording medium is uniform, the humidity sensor 40 corresponding to the other side portion of the recording medium may be omitted.

  Further, in the example of FIG. 14D, a plurality of (for example, three) humidity sensors 40 are not in a direction completely perpendicular to the recording medium conveyance direction (hereinafter, also simply referred to as “conveyance direction”), but are adjacent to each other. The humidity sensor 40 is arranged in a state shifted in the transport direction (X-axis direction). This is because, for example, in the case of a serial head in which the droplet discharge head is movable in the direction perpendicular to the transport direction (Y-axis direction), the recording material passes through the position facing each humidity sensor 40 after adhering to the recording medium. This is to keep the time until the operation is constant. Thus, the recording amount of the two humidity sensors 40 adjacent to each other in the transport direction (X-axis direction) is recorded with respect to the operation speed in the direction (Y-axis direction) perpendicular to the transport direction of the droplet discharge head (serial head). What is necessary is just to make it the value which multiplied the ratio of the conveyance speed of a medium, and the space | interval (Y-axis direction) of the direction (Y-axis direction) orthogonal to the conveyance direction of the said two adjacent humidity sensors 40.

  Further, as shown in FIG. 15, the position of the humidity sensor 40 may be variable at least in a range facing the recording medium in a direction non-parallel to the conveyance direction of the recording medium (for example, the Y axis direction). In this case, the position of the humidity sensor 40 can be adjusted according to the test pattern or the actual image. Specifically, a drive unit (for example, a linear actuator) that moves the humidity sensor 40 in a direction (for example, the Y-axis direction) non-parallel to the conveyance direction of the recording medium can be provided. Examples of the linear actuator include those including a linear motor, a rack and pinion mechanism, a feed screw mechanism, a solenoid mechanism, and the like.

  When adopting a configuration capable of measuring in a wide range in the Y-axis direction as in the examples of FIGS. 14 and 15, for example, as shown in FIG. 16, a direction (Y-axis direction) perpendicular to the conveyance direction of the recording medium is used. ) And a test pattern 2 in which a plurality of strip-like patterns (image portions) having a length equivalent to the width of the recording medium are arranged in the conveying direction may be used. As shown in FIG. 17, the conveying direction of the recording medium is used. Alternatively, a test pattern 3 composed of a plurality of patterns arranged in a matrix in a direction orthogonal to the transport direction may be used. In the test patterns 2 and 3, since the total area of the image portion is large and does not differ greatly from the actual printed image, it is possible to detect the dry state of the image close to actual use. Note that the test pattern may be other than the test patterns 1 to 3, for example, a plurality of image portions may be arranged in a staggered pattern.

  As described above, in the above-described embodiment, an example in which a dedicated test pattern is used to detect the dry state has been shown. This is effective, for example, for confirming the dry state at a predetermined time (for example, regularly) or at a predetermined frequency (a predetermined number of copies or a predetermined number of jobs). In addition, the image processing process in the present embodiment may be started by detecting that the power of the liquid droplet ejection device is turned on, or by separately detecting an external input to the liquid droplet ejection device. As such, it may be configured to wait for a user instruction.

  On the other hand, in order to compensate for stable images in response to environmental changes over a short period of time, or to save energy by eliminating wasted energy in response to environmental changes, it is necessary to continuously dry the image using images. It is preferable to monitor.

  In addition, a method of quantifying the dry state using an actual image (an image actually formed by the droplet discharge device 100) instead of a dedicated test pattern will be described with reference to FIG. The flowchart in FIG. 26 is based on a processing algorithm executed by the main control unit 50. The processing here follows the example of using the above-described dedicated test pattern.

  When an actual image is used instead of a dedicated test pattern, after receiving the image data of the actual image (step Q1), the high density portion of the recording material in the image data of the actual image is selected as the image portion in the above test pattern. (Step Q3), a portion having a low recording material density in the image data of the actual image is selected as a non-image portion in the test pattern (Step Q5), and printing is performed on the recording medium (Step Q7).

  Then, the atmospheric state in the vicinity of the recording medium is detected (step Q9), the value of (A) is obtained (step Q11), the value of (B) is obtained (step Q13), and the absolute humidity representing the dry state is obtained. The difference (A)-(B) is obtained (step Q15).

  As described above, the main control unit 50 detects the state of the recording medium based on the output of the humidity sensor 40 for the actual image as the image formed on the recording medium by the printing unit 10.

  As shown in FIG. 15, in the case where the position in the direction orthogonal to the conveyance direction of the humidity sensor 40 (Y-axis direction) is variable, the difference in the density of the recording material in the actual image on the recording medium is large. You may move the humidity sensor 40 to a part.

  On the other hand, when the humidity sensor 40 cannot be moved in the Y-axis direction, the difference in density of the recording material in the transport direction (X-axis direction) in the actual image on the recording medium at the position of the humidity sensor 40 in the Y-axis direction. Is selected and the position information in the X-axis direction is recorded. Then, the above (A) and (B) are obtained from the output of the humidity sensor 40 corresponding to the recorded position information, and the absolute humidity difference (A)-(B) representing the dry state is calculated.

<< Modification 1 >>
Hereinafter, an image forming method according to Modification 1 will be described with reference to FIG. The flowchart in FIG. 18 is based on a processing algorithm executed by the main control unit 50. This flow is started when the main control unit 50 receives a job start request from a host device (for example, a personal computer).

  In the first step U1, “dry output adjustment processing 1” (see FIG. 13) is performed.

  In the next step U3, an image is formed on the recording medium. Specifically, the droplet discharge head 10a is controlled to discharge droplets onto the recording medium based on the image information.

  In the next step U5, the image is dried. Specifically, the drying unit 30 is controlled via the drying condition control unit 120 so that the drying output that is initially set or adjusted in the drying output adjustment processing 1 is obtained.

  In the next step U7, it is determined whether or not the job is finished. If the determination here is affirmed, the process proceeds to step U9, and if the determination is negative, the process proceeds to step U11.

  In step U9, the conveyance of the recording medium is stopped. When step U9 is executed, the flow ends.

  In step U11, “dry output adjustment processing 2” is performed. The dry output adjustment process 2 will be described later.

  Next, the dry output adjustment process 2 will be described with reference to FIG. The flowchart in FIG. 19 is based on a processing algorithm executed by the main control unit 50.

  In the first step V1, the state of the atmosphere in the vicinity of the recording medium is detected. Specifically, the output signal of the humidity sensor 40 is acquired while the actual image formed on the recording medium passes through the position facing the humidity sensor 40.

  In step V1, the position of the humidity sensor 40 may be changed, and for example, the air in the vicinity of the portion where the recording material density of the image formed on the recording medium is high may be measured.

  In the next step V3, time t1 is calculated. The time t1 is the sum of a value obtained by dividing the distance L by which the recording medium is fed from the unwind roller pair 8 to the printing unit 10 by the conveyance speed V of the recording medium and the droplet discharge time t0 in the printing unit 10.

  In the next step V5, an average value (A) of absolute humidity over a predetermined time including n image portions after t1 is obtained.

  In the next step V7, an absolute humidity serving as a reference value is obtained. Specifically, an average value immediately before each image portion (for example, 0.6 seconds) is set as a reference value (B).

  In the next step V9, the dry state of the image is obtained. Specifically, “the average value (A) −the reference value (B)” is set to a dry state.

  In the next step V11, it is determined whether or not the drying is insufficient. Specifically, when the obtained image dry state is negative and the absolute value is equal to or greater than the threshold value Dth, it is determined that the image is insufficiently dried, and in other cases, it is determined that the image is not insufficiently dried. If the determination here is affirmed, the process proceeds to step V13, and if the determination is negative, the process proceeds to step V15.

  In step V13, the drying output is increased. Here, the change in the dry state with respect to the change in the dry output is acquired in advance, and a table representing the correspondence between the dry output and the dry state is stored in the storage unit 70. Therefore, the main control unit 50 refers to this table and raises the drying output from the original value so that the absolute value of the drying state is less than the threshold value Dth. When step V13 is executed, the flow ends.

  In step V15, it is determined whether or not there is excessive drying. Specifically, it is determined that the image has been dried excessively when the dry state of the obtained image is positive and the absolute value is equal to or greater than the threshold value Dth, and otherwise it is determined that the image is not excessively dried. If the determination here is affirmed, the process proceeds to step V17. If the determination is negative, the flow ends.

  In step V17, the drying output is lowered. Here, the main control unit 50 refers to the above table and lowers the drying output from the original value so that the absolute value of the dry state is less than the threshold value Dth. When step V17 is executed, the flow ends.

  As can be seen from the above description, in the image forming method of the first modification, after the dry state of the test pattern 1 is first obtained and the dry output is adjusted as necessary, the dry state of the image is changed each time an image is formed. Because all the images from the first image to the last image in one job are appropriate regardless of changes in the surrounding environment (for example, temperature change, humidity change, atmospheric pressure change, etc.) The recording medium can be dried with a sufficient drying output (the recording medium can be dried without excess or deficiency).

<< Modification 2 >>
Hereinafter, an image forming method of Modification 2 will be described with reference to FIG. The flowchart in FIG. 20 is based on a processing algorithm executed by the main control unit 50. This flow is started when the main control unit 50 receives a job start request from a host device (for example, a personal computer). Initially, the drying output is set to the standard value.

  In the first step W1, conveyance of the recording medium is started. Specifically, the conveyance unit 20 is controlled to send the recording medium from the upstream side to the downstream side of the conveyance path.

  In the next step W3, an image is formed on the recording medium. Specifically, the droplet discharge head 10a is controlled to discharge droplets onto the recording medium based on the image information.

  In the next step W5, the image is dried with the set drying output. Specifically, the drying unit 30 is controlled via the drying condition control unit 120 so that the drying output that is initially set or adjusted in the drying output adjustment processing 1 is obtained.

  In the next step W7, it is determined whether or not the job is finished. If the determination here is affirmed, the process proceeds to step W9, and if the determination is negative, the process proceeds to step W11.

  In step W9, the conveyance of the recording medium is stopped. When step W9 is executed, the flow ends.

  In step W11, “dry output adjustment processing 2” (see FIG. 19) is performed.

  As can be seen from the above description, in the second modification, the first image is dried with the drying output set as the standard value that is initially set, but the subsequent images are dried with a more appropriate drying output. Drying can be performed. In this case, it is not necessary to prepare a test pattern.

<< Modification 3 >>
Hereinafter, an image forming method of Modification 3 will be described with reference to FIG. The flowchart in FIG. 21 is based on a processing algorithm executed by the main control unit 50. This flow is started when the main control unit 50 receives a job start request from a host device (for example, a personal computer). Initially, the drying output is set to the standard value.

  In the first step Y1, “dry output adjustment processing 1” (see FIG. 13) is performed.

  In the next step Y3, an image is formed on the recording medium. Specifically, the droplet discharge head 10a is controlled to discharge droplets onto the recording medium based on the image information.

  In the next step Y5, the image is dried. Specifically, the drying unit 30 is controlled via the drying condition control unit 120 so that the drying output that is initially set or adjusted in the drying output adjustment processing 1 is obtained.

  In the next step Y7, it is determined whether or not the job is finished. If the determination here is affirmed, the process proceeds to step Y9. If the determination is negative, the process proceeds to step Y11.

  In step Y9, the conveyance of the recording medium is stopped. When step Y9 is executed, the flow ends.

  In step Y11, it is determined whether or not a predetermined time (for example, several minutes to several hours) has elapsed since the drying output was initially set or adjusted last time. The time measurement here is performed by the time measuring unit 80. If the determination here is affirmed, the process returns to step Y1, and if the determination is negative, the same determination is made again.

  As can be seen from the above description, in the modified example 3, since the dry output adjustment process 1 is first performed and then the dry output adjustment process 1 is performed at predetermined intervals, the temperature change, humidity change, and atmospheric pressure change of the surrounding environment. Etc., the drying output can be controlled to an appropriate value.

  In Step Y11 of Modification 3, it may be determined whether or not a predetermined number of copies have been completed since the drying output was initially set or adjusted last time.

<< Modification 4 >>
FIG. 22 shows a schematic configuration of a droplet discharge device 200 of Modification 4. The droplet discharge device 200 has a configuration corresponding to a sheet as a recording medium.

  As shown in FIG. 22, the droplet discharge device 200 includes a paper feed tray on which recording media (sheets) are stacked, a paper feed roller group for taking out the recording media one by one from the paper feed tray, A registration roller group disposed downstream of the sheet feeding roller group, a printing unit 10 disposed downstream of the registration roller group, a drying unit disposed downstream of the printing unit 10, and the drying unit A humidity sensor 40 disposed downstream of the humidity sensor 40, a folding roller disposed downstream of the humidity sensor 40, a paper discharge roller pair disposed downstream of the folding roller, and a downstream of the paper discharge roller pair. And a paper discharge tray disposed on the side.

  In the fourth modification, the drying unit includes a selective heating unit and a uniform heating unit disposed on the downstream side of the selective heating unit. The printing unit 10 is disposed on the downstream side (+ X side) of the registration roller group and on the −Z side of the droplet discharge head 10a (facing the droplet discharge head 10a), and the recording medium from the sheet feed roller group is downstream. It has a feed mechanism 10b for sending to the side. As an example, the feed mechanism 10b includes a plurality of rollers whose axial direction is the Y-axis direction, a platen belt (endless belt) hung on the plurality of rollers, and a recording medium for adsorbing and holding the recording medium on the platen belt. And a suction part such as a suction fan.

  Also in the droplet discharge device 200 of the modification 4, the control device obtains the dry state of the droplet and adjusts the dry output based on the dry state in the same manner as the droplet discharge device of the above-described embodiment and each modification. And it is possible to dry the image with the dry output after adjustment.

In Modification 4, it is preferable to form a test pattern (for example, a solid pattern) as small as possible on a recording medium as small as possible from the viewpoint of speeding up and resource saving.
In the fourth modification, the state of the recording medium may be detected by using the actual image instead of the test pattern and following the procedure of the flowchart in FIG.

<< Modification 5 >>
FIG. 23 shows a schematic configuration of a droplet discharge device 300 of Modification 5. The droplet discharge device 300 is obtained by adding the feeding mechanism 10b described in the modification 4 to the droplet discharge device 100 of the above embodiment and combining a drying unit with a selective heating unit and a uniform heating unit. is there.

  In the above-described embodiment and each modified example, the drying output is adjusted based on the output change of the humidity sensor 40. Alternatively, the conveyance speed of the recording medium by the conveyance unit 20 may be adjusted. . Specifically, when it is desired to dry more, the conveyance speed is decreased. On the other hand, when the drying is excessive, the conveyance speed is increased. For example, in the flowchart of FIG. 13, step T19 may be changed to “decrease the conveyance speed”, and step T23 may be changed to “increase the conveyance speed”. Further, for example, in the flowchart of FIG. 19, step V13 may be changed to “decrease the conveyance speed” and step V17 may be changed to “increase the conveyance speed”.

  In this case, the conveyance speed control method of Modification 6 and the image forming methods of Modifications 7 and 8 described below can be performed.

  In the transport speed control method of Modification 6, the transport speed of a recording medium that is transported on a predetermined transport path, droplets are ejected in a first area on the transport path, and dried in a second area on the transport path is set. A method for controlling a conveyance speed to be controlled, the step of detecting the state of the atmosphere in the vicinity of the recording medium when the recording medium dried in the second area is in the third area on the conveyance path, and the detection A step of detecting a state of the recording medium based on a detection result in the step, a conveyance speed between the first and second regions, and a conveyance between the second and third regions based on the state of the recording medium. Adjusting at least one of the speeds.

  The image forming method of Modification 7 includes a step of forming an image by ejecting liquid droplets onto a recording medium located in a first area on a predetermined conveying path, and a recording unit on which the image is formed by the conveying unit 20. A step of transporting from one region to a second region on the transport path, a step of drying an image on a recording medium located in the second region by the drying unit 30, and a transporting unit 20 for recording the recording medium on which the image has been dried. Based on the detection result in the step of transporting from the second region to the third region on the transport path, detecting the state of the atmosphere in the vicinity of the recording medium located in the third region, and A step of detecting the state of the recording medium, a step of adjusting the conveyance speed of the recording medium between the first and second regions by the conveyance unit 20 based on the state of the recording medium, and a position in the first region Forming an image by ejecting liquid droplets onto another recording medium , Transporting another recording medium on which an image is formed from the first area to the second area by the transport unit 20 at the adjusted transport speed, and on another recording medium positioned in the second area. Drying the image.

  The image forming method of Modification 8 includes a step of ejecting droplets onto a recording medium located in a first area on a predetermined conveyance path to form an image, and a recording medium on which the image is formed is conveyed by a conveyance unit 20. A step of transporting the first region from the first region to the second region on the transport path, a step of drying the image on the recording medium located in the second region, and a second step of transporting the recording medium on which the image has been dried by the transport unit 20. A step of transporting the recording medium from the region to the third region on the transport path, a step of detecting the state of the atmosphere in the vicinity of the recording medium located in the third region, and a detection result of the recording medium based on the detection result in the detecting step A step of detecting a state, a step of adjusting the conveyance speed of the recording medium between the second and third regions by the conveyance unit 20 based on the state of the recording medium, and another step located in the first region A step of ejecting droplets onto a recording medium to form an image; A step of transporting another formed recording medium from the first region to the second region by the transport unit 20, a step of drying an image on another recording medium located in the second region, and the image And transporting the dried recording medium from the second region to the third region by the transport unit 20 at the transport speed after adjustment.

  Further, the test pattern may be a single solid pattern that is elongated in the conveyance direction of the recording medium, for example. In this case, the dry state may be obtained by adjusting the dry state by regarding the plurality of solid patterns as a plurality of different portions of the solid pattern in the conveyance direction of the recording medium, and determining the dry state.

  In addition, in the liquid droplet ejection devices of the above-described embodiment and each modified example, an image is formed based on image data from a personal computer or the like. In addition, a scanner that reads an original image is provided, and the scanner reads the image. An image may be formed based on the obtained image data.

  In the above embodiment and each modification, the control device 150 of the droplet discharge device 100 detects the dry state of the droplets. However, the processing device is provided separately, and the processing device is based on the output of the humidity sensor 40. Then, the dry state of the droplets may be detected.

In the above-described embodiment and each modification, a sheet-like recording medium (for example, recording paper) is used as a recording medium from which droplets are ejected. However, the material and shape of the recording medium are not limited thereto. . For example, examples of the recording medium material include paper, plastic, metal, alloy, ceramic, cloth, and wood. Further, the recording medium may be a flat one such as a sheet or a plate, for example, a fluffy one or a three-dimensional shape.
For example, the circuit device may be manufactured by discharging a wiring material or a semiconductor material, which is a recording material, from a discharge device to a substrate as a recording medium. In this case, it is preferable to use the thermal conductivity of the atmosphere as the state of the atmosphere in the vicinity of the substrate. Since the thermal conductivity of the atmosphere varies depending on the concentration of the recording material in the atmosphere, specifically the concentration of the solvent of the recording material, the concentration of the recording material (the state of the recording material) is determined by measuring the thermal conductivity. Can be detected.

  In the above-described embodiment and each modification, the humidity sensor is disposed to face the surface opposite to the surface on which the recording paper droplets are ejected, but the surface on which the recording paper droplets are ejected. You may arrange | position facing. Further, the configuration of the humidity sensor can be changed as appropriate.

  The image forming apparatus of the present invention is not limited to the liquid droplet ejecting apparatus of the above-described embodiment and each modified example. For example, the image forming apparatus of the present invention may be configured by a coating apparatus that applies a recording material to a recording medium.

  Moreover, although the droplet discharge apparatus of the said embodiment and each modification has the drying part 30, it does not need to have it. For example, in the case where the present invention is applied to a home-use liquid droplet ejection apparatus that does not require high-speed conveyance, the drying unit may not be provided. In this case, for example, the dry condition of the droplets discharged onto the recording medium due to natural drying is detected by a sensor device including the humidity sensor 40, and the conveyance speed of the recording medium is controlled based on the detection result. You may control a dry state.

  Furthermore, the sensor device of the above-described embodiment is not limited to the use application in the above-described embodiment and each modified example, and can be used, for example, in a recording device, a device inspection device, or a food component inspection. is there.

  DESCRIPTION OF SYMBOLS 10 ... Printing part (image formation part), 20 ... Conveyance part (conveyance apparatus), 30 ... Drying part (drying apparatus), 40 ... Humidity sensor, 50 ... Main control part (detection part), 100 ... Droplet discharge apparatus ( Image forming apparatus), 110... Transport condition control unit (part of control means), 120... Drying condition control unit (part of control means).

Japanese Patent Laying-Open No. 2015-66821

Claims (22)

At least one sensor for detecting the state of the atmosphere in the vicinity of the recording medium to which the recording material is attached;
And a detection unit that detects a state of the recording medium based on an output of the sensor. A sensor device according to claim 1;
A transport device for transporting the recording medium on a transport path including a position where the recording material is attached and a position facing the sensor of the sensor device;
A drying apparatus that dries the recording material on the recording medium located on the conveyance path between the attached position and the facing position.   The system according to claim 2, wherein the sensor faces a surface of the recording medium opposite to a surface to which the recording material is attached.   The system according to claim 2, wherein the at least one sensor is a plurality of sensors arranged in a direction non-parallel to the conveyance path.   The system according to claim 2, further comprising a drive unit that moves the sensor in a direction non-parallel to the conveyance path.   The system according to claim 2, further comprising a control unit that controls a dry state of the recording material based on a state of the recording medium detected by the sensor device.   The system according to claim 6, wherein the control unit controls the drying device based on a state of the recording medium.   The system according to claim 6, wherein the control unit controls the transport device based on a state of the recording medium. A system according to any one of claims 2 to 8;
An image forming apparatus comprising: an image forming unit that forms an image by attaching a recording material to a recording medium located at the attachment position.   The image forming apparatus according to claim 9, wherein the image forming unit forms a test pattern as the image for detecting a state of the recording medium on the recording medium.   The image forming apparatus according to claim 10, wherein the test pattern includes a plurality of patterns arranged in a direction parallel to the conveyance path.   The relationship between the length L1 of the test pattern in the direction parallel to the conveyance path and the length L2 of the non-image portion in the direction parallel to the conveyance path is L1 <L2. Item 12. The image forming apparatus according to Item 11.   The image forming apparatus according to claim 12, wherein L2 ≦ 1.5L1.   The image forming apparatus according to claim 10, wherein the test pattern includes a plurality of patterns arranged in a direction non-parallel to the conveyance path.   The image forming apparatus according to claim 10, wherein the test pattern includes a pattern extending in a direction non-parallel to the conveyance path.   The said detection part detects the state of the said recording medium based on the output of the said sensor with respect to the real image as the said image formed in the said recording medium by the said image formation part. Image forming apparatus. Detecting the state of the atmosphere in the vicinity of the recording medium to which the recording material is attached;
And a step of detecting a state of the recording medium based on a detection result in the detecting step. An output control method for controlling the output of a drying apparatus for drying a recording material attached to a recording medium conveyed on a predetermined conveyance path,
Drying the recording material attached to the recording medium with the drying device;
Detecting the state of the atmosphere in the vicinity of the recording medium in which the recording material is dried by the drying device;
Detecting a state of the recording medium based on a detection result in the detecting step;
Adjusting the output of the drying device based on the state of the recording medium. A transport speed control method for controlling a transport speed of a recording medium that is transported on a predetermined transport path, on which a recording material is attached in a first area on the transport path and is dried in a second area on the transport path. ,
Detecting the state of the atmosphere in the vicinity of the recording medium that is dried and positioned in the third region on the transport path;
Detecting a state of the recording medium based on a detection result in the detecting step;
Adjusting at least one of the transport speed between the first and second regions and the transport speed between the second and third regions based on the state of the recording medium. Control method. Forming an image by attaching a recording material to a recording medium located in a first region on a predetermined conveyance path;
Transporting the recording medium on which the image is formed from the first region to a second region on the transport path;
Drying the image on the recording medium located in the second region with a drying device;
Transporting the recording medium on which the image has been dried from the second region to a third region on the transport path;
Detecting an atmosphere in the vicinity of the recording medium located in the third region;
Detecting a state of the recording medium based on a detection result in the detecting step;
Adjusting the output of the drying device based on the state of the recording medium;
Forming an image by attaching a recording material to another recording medium located in the first region; and
Transporting the another recording medium on which the image is formed from the first area to the second area;
Drying the image on the other recording medium positioned in the second area with the drying device with the output adjusted. Forming an image by attaching a recording material to a recording medium located in a first region on a predetermined conveyance path;
Transporting the recording medium on which the image is formed from the first region to a second region on the transport path by a transport device;
Drying the image on the recording medium located in the second region;
Transporting the recording medium on which the image has been dried from the second region to a third region on the transport path by the transport device;
Detecting an atmosphere in the vicinity of the recording medium located in the third region;
Detecting a state of the recording medium based on a detection result in the detecting step;
Adjusting the conveyance speed of the recording medium between the first and second regions by the conveyance device based on the state of the recording medium;
Forming an image by attaching a recording material to another recording medium located in the first region; and
Transporting the another recording medium on which the image is formed from the first area to the second area at the adjusted transport speed;
Drying the image on the another recording medium located in the second region. Forming an image by attaching a recording material to a recording medium located in a first region on a predetermined conveyance path;
Transporting the recording medium on which the image is formed from the first region to a second region on the transport path by a transport device;
Drying the image on the recording medium located in the second region;
Transporting the recording medium on which the image has been dried from the second region to a third region on the transport path by the transport device;
Detecting an atmosphere in the vicinity of the recording medium located in the third region;
Obtaining a state of the recording medium based on a detection result in the detecting step;
Adjusting the conveyance speed of the recording medium between the second and third regions by the conveyance device based on the state of the recording medium;
Forming an image by attaching a recording material to another recording medium located in the first region; and
Transporting the another recording medium on which the image is formed from the first area to the second area by the transport device;
Drying the image on the other recording medium located in the second region;
Transporting the another recording medium on which the image has been dried from the second area to the third area by the transport device at the transport speed after the adjustment.

Images