JP7000668B2 - System, image forming device, dry state detection method, output control method, transport speed control method and image formation method - Google Patents

Description

The present invention relates to a system, an image forming apparatus, a dry state detecting method, an output control method, a transport speed control method, and an image forming method.

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

However, the dryness detection unit including the optical sensor disclosed in Patent Document 1 brings another object into contact with the portion to which the recording material of the recording medium that has undergone the drying step adheres, and determines whether or not the recording material has been transferred to the object. It is optically detected, that is, it is used for a simple picking inspection, and the state of the recording medium cannot be detected accurately.

The present invention relates to at least one heat conduction type humidity sensor that is located facing a surface opposite to the surface of the recording medium on which the recording material is attached to a predetermined surface and detects the state of the atmosphere in the vicinity of the recording medium. A sensor device having a detection unit that detects the state of the recording medium based on the output of the humidity sensor, a position where the recording material is attached, and a position of the sensor device facing the humidity sensor. The recording material on the recording medium located on the transfer path between the transfer device having a transfer roller for transporting the recording medium in the transport direction on the transport path including the transfer path and the position where the recording medium is attached and the opposite position. The sensor device is provided between the drying device and the transport roller, and is arranged in the vicinity of the transport roller separated from the drying device. It is a system.

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

It is a figure which shows the schematic structure of the droplet ejection device which concerns on one Embodiment. It is a figure for demonstrating the arrangement 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 the state that water vapor 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 how the water vapor moves when the droplet is overdried. It is a figure which shows an example of the output of a humidity sensor when there is no excess or deficiency in drying of a droplet. It is a figure for demonstrating the method of quantifying the dry state of a droplet. It is a block diagram which shows an example of the hardware composition of the droplet ejection device. It is a flowchart for demonstrating the image formation method of one Embodiment. It is a flowchart for demonstrating the dry output adjustment process 1. 14 (a) to 14 (d) are diagrams for explaining an example (No. 1 to No. 4) in which a plurality of humidity sensors are arranged. It is a figure for demonstrating an example in which the position of a humidity sensor is variable. It is a figure for demonstrating the test pattern 2. It is a figure for demonstrating the test pattern 3. It is a flowchart for demonstrating the image formation method of the modification 1. It is a flowchart for demonstrating the dry output adjustment process 2. It is a flowchart for demonstrating the image formation method of the modification 2. It is a flowchart for demonstrating the image formation method of the modification 3. It is a figure for demonstrating the droplet ejection apparatus of the modification 4. It is a figure for demonstrating the droplet ejection apparatus of the modification 5. It is a graph which shows the relationship between a drying condition and an absolute humidity difference (A)-(B). It is a relational 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 quantifying the dry state using a real image.

<< Embodiment >>
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 13. FIG. 1 shows a schematic configuration of a droplet ejection device 100 of an embodiment, which is an example of the image forming apparatus of the present invention.

As shown in FIG. 1, the droplet ejection device 100 includes a control device 150 (see FIG. 11) including a printing unit 10, a transport unit 20, a drying unit 30, a humidity sensor 40, and a main control unit 50. .. The main control unit 50 has, for example, a CPU, and controls each of the above-mentioned components of the droplet ejection device 100 in an integrated manner.

Hereinafter, the XYZ three-dimensional Cartesian coordinate system shown in FIG. 1 and the like will be described as appropriate.

The transport 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 out to the downstream side (+ X side).

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

The printing unit 10 is arranged on the downstream side (+ X side) of the unwind roller pair 8 and adheres the recording material to the recording medium to form an image. As an example, the printing unit 10 has a droplet ejection head 10a that ejects droplets made of a recording material.
Examples of the "recording material" include, but are not limited to, water-based inks, oil-based inks, heat-dissolving inks, dye inks, pigment inks, pulverized toners, polymerized toners, and wet developing toners.

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

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

The drying unit 30 is arranged on the downstream side (+ X side) of the printing unit 10, and the recording medium on which an image is formed by the printing unit 10 and wet with droplets is dried.

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, the dielectric heating and the uniform heating of the recording medium are performed at different timings.

The dielectric heating device is a selective heating means capable of selecting a heating target, typified 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 the droplets more efficiently than the general heating method by applying energy to the 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.

The uniform heating device is a device that heats a recording medium moistened with droplets substantially evenly, and many of them can be realized by a general heating method. Broadband IR radiant heating typified by hot air heating, a heat drum, and a ceramic heater. And so on.

The guide roller 15 is arranged 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 arranged near the transport path of the recording medium between the drying unit 30 and the guide roller 15 (see FIG. 1), and the drying unit 30 detects the state of the atmosphere in the vicinity of the recording medium on which the image is dried. do.
The "state of atmosphere 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 arranged so as to face the center in the width direction of the transport path of the recording medium (see FIG. 2). The humidity sensor 40, together with the main control unit 50, constitutes a "sensor device" that detects the state of the recording medium.
The "state of the recording medium" means the dry state of the droplet in the recording medium, and uses indexes such as the impregnation degree, the fixing degree, the penetrance, the height, the stability, and the elasticity of the droplet with respect to the recording medium. Is detected. Details of the humidity sensor 40 will be described later.
Further, as shown in FIG. 1, the humidity sensor 40 is preferably arranged on the surface side of the recording medium opposite to the surface to which the recording material adheres, 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.
Further, in order to stabilize the distance from the recording medium, the humidity sensor 40 is preferably installed in the vicinity of other constituent members in the vicinity of the transport path of the recording medium or integrally configured with 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 component.

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

The rewind roller pair 18 is a drive roller 18a arranged on the downstream side of the first touch roller 16 (diagonally above the + X side and the + Z side), with the Y-axis direction as the axial direction, and the outer peripheral surfaces contacting each other to form a nip portion. And the driven roller 18b, the recording medium dried by the drying portion 30 is conveyed to the downstream side while being sandwiched between the nip portions. The drive roller 18a is controlled by the main control unit 50.

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

Upon receiving a print request from a host device (for example, a personal computer), the main control unit 50 synchronously drives the two drive rollers 8a and 18a to feed the recording medium from the upstream side to the downstream side while driving the droplet ejection head 10a. After driving to form an image on the recording medium and drying the portion of the recording medium on which the image is formed 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 ejection head 10a based on image data from a host device (for example, a personal computer).

The humidity sensor 40 will be described in detail below. FIG. 3 shows an XZ cross-sectional view of the humidity sensor 40. The humidity sensor 40 is a heat conduction type humidity sensor, and detects the state of the atmosphere in the vicinity. The humidity sensor 40 includes a sensor package 51, a sensor device case 60, a moisture permeable membrane 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 inside of the sensor package 51 is hollow, and the humidity detection chip 52 is joined 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 come out 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 arranged so that the lower surface of the sensor package 51 is below the bottom surface 60a of the recess 61.

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

A recess 61 is provided on the upper surface of the sensor device case 60, and an opening 63 penetrating the sensor device case 60 in the thickness direction is provided at the center of the recess 61. The opening 63 has a shape having a circular shape at the four corners of the 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 arranged 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 membrane 75 allows water vapor as a gas to permeate, but does not allow liquid water to permeate. 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 (the inner surface of the sensor device case 60 and the inner surface opposite to the opening 63) in the welding portion 70a by a heat welding method. .. Further, the moisture permeable membrane 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, the 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 arranged so as to push the flexible substrate 81 and the sensor package 51 into the sensor device case 60. As a result, 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 arranged near the + Z side of the transport path of the recording medium. Since the humidity detection chip 52 is manufactured using the MEMS technique, it can be reduced to a size of several mm, and as a result, the size of the entire 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 penetrating in the thickness direction. The humidity sensor 40 is fixed to the guide plate 46 so that the lower portion of the humidity sensor 40 is housed 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 way, the humidity sensor 40 is arranged in the vicinity of the recording medium to be conveyed, at a certain distance from the recording medium.

As described above, the humidity sensor 40 is arranged near the transport path of the recording medium between the drying unit 30 and the guide roller 15 which is the roller that first touches the recording medium after the droplets are dried by the drying unit 30. .. The droplets on the recording medium energized by the drying unit 30 proceed to dry while the recording medium moves in the transport section from the drying unit 30 to the humidity sensor 40. The droplets ejected to the recording medium by the printing unit 10 also undergo drying while the recording medium moves in the transport section from the printing unit 10 to the drying unit 30.

By arranging 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, so that the humidity sensor 40 is the recording medium. Absolute humidity of nearby air can be detected. The closer the humidity sensor 40 is to the recording medium, the more accurately the humidity sensor 40 can detect the absolute humidity of the air in the vicinity of 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 repeated contact with the recording medium to which the moisture permeable film 75 is conveyed. be. Further, when the lower surface of the moisture permeable film 75 is above the lower surface of the sensor device case 60, foreign matter such as paper dust generated from the recording medium is deposited on the lower surface of the moisture permeable film 75, so that the humidity detection chip 52 The output may be reduced and the response of the humidity detection chip 52 may be delayed. Therefore, as described above, the humidity sensor 40 is provided 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.

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

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 is the elapsed time, and the vertical axis is the output (absolute humidity) of the humidity sensor 40. Here, as the test pattern 1, a test pattern in which six image portions are formed along the transport direction of the recording medium is used.

When the image portion of the test pattern 1 approaches the position facing the humidity sensor 40 when the droplets are insufficiently dried, the water vapor diffused from the droplets in the image portion into the air permeates 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.

Then, when the image unit passes the position facing the humidity sensor 40 and the non-image unit approaches the position, the thermal conductivity and humidity of the air in the vicinity of the humidity sensor 40 become low.

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

After the drying peak is passed, the droplets dried by applying excessive energy absorb moisture from the nearby air, so that the thermal conductivity and humidity of the air become low.

When the image portion of the test pattern 1 approaches the position facing the humidity sensor 40 when the droplets are excessively dried, the droplets in the image portion absorb moisture from the nearby air, and the air in the vicinity of the humidity sensor 40 Thermal conductivity and humidity decrease.

Then, when the image unit passes the position facing the humidity sensor 40 and the non-image unit approaches the position, the thermal conductivity and humidity of the air in the vicinity of the humidity sensor 40 increase. FIG. 8 shows how the water vapor moves when the droplets are overdried.

That is, in the droplet ejection device 100, when the drying is insufficient, moisture diffuses from the droplets and permeates through the recording medium, so that the thermal conductivity and humidity of the air in the vicinity of the humidity sensor 40 increase. On the contrary, when the drying is excessive, the droplets absorb moisture from the atmosphere, and the thermal conductivity and humidity of the air in the vicinity of the humidity sensor 40 become low.

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 is the elapsed time, and the vertical axis is the output (absolute humidity) of the humidity sensor 40. Here, as the test pattern 1, a test pattern 1 in which six image portions are formed along the transport direction of the recording medium is used.

In FIG. 9, there is no significant difference in the humidity in the vicinity of the image portion where the droplets are attached to the recording medium and the non-image portion where the droplets are not attached as seen in FIGS. 5 and 7. It can be seen that it is completely dried.

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

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 higher in the non-image portion. It is preferable that it is longer than the image portion, and it is preferable that the length of the entire test pattern 1 in the transport direction is as short as possible. It is preferable to set the ratio of the length of the image portion in the transport direction to 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 the droplet will be described with reference to FIG. 10. Although the description will be given by taking the case of insufficient drying shown in FIG. 10 as an example, the same description holds true even when the time is excessively dried. Here, as the test pattern 1, a test pattern in which n image portions are formed at equal intervals along the transport direction of the recording medium is used.

First, the average value (A) of the absolute humidity of the section including the five image portions in the test pattern 1 is obtained. Next, the absolute humidity, which is the reference value, is obtained. Specifically, the average value of the absolute humidity for 0.6 seconds immediately before the second to fifth image portions is used as the reference value (B). Here, an example in which the average value is used for (A) and (B) will be described, but the present invention is not limited to this. For example, the total of the absolute humidity of the section including the above five image parts may be set as (A), and the total of the absolute humidity for 0.6 seconds immediately before the second to fifth image parts may be set as (B). Is also good.

The difference between the average value (A) and the reference value (B) is used as an index 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 , the drying is insufficient. In FIG. 24, as the energy applied to the recording medium under the drying conditions is increased, the value of the absolute humidity difference (A)-(B) becomes smaller, and when it is smaller than 0.5 g / m ³ , it can be sufficiently dried. There is. Further, when the energy applied to the recording medium is increased, the absolute humidity difference (A)-(B) becomes negative. This indicates that the recording medium releases the moisture at the position facing the drying portion 30, and then absorbs the moisture in the air when the recording medium deviates from the position.

FIG. 11 shows a block diagram showing the hardware configuration of the droplet ejection device 100.

In addition to the above-mentioned printing unit 10, transport unit 20, drying unit 30, humidity sensor 40, and main control unit 50, the droplet ejection device 100 includes an environmental information measuring unit 65 and a storage unit 70, as shown in FIG. (Memory and hard disk), a time measuring 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 above components is communicably connected via a bus line. The control device 150 includes a main control unit 50, a storage unit 70, a timekeeping unit 80, an image forming condition control unit 90, a transport condition control unit 110, and a drying condition control unit 120.

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

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

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

Here, it is preferable to obtain the dry state by the method described with reference to FIG. 10, feed back the result, and correct the control of the printing unit 10, the transport unit 20, or the drying unit 30.

Specifically, when the drying is insufficient, the drying output is increased, the transport speed is slowed down, or the water content of the droplet is reduced. On the other hand, when it is excessively dried, the drying output is lowered, the transport speed is increased, and the water content of the droplet is increased.

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

The environmental information measuring unit 65 measures, for example, at least one of ambient temperature, humidity, and atmospheric pressure. The drying rate of the droplets is greatly affected by the water vapor pressure, which is highly temperature-dependent. Since the fluctuation of the atmospheric pressure can be an error when measuring the thermal conductivity of a gas, it is necessary to consider it when measuring it with a heat conduction type humidity sensor and correcting 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 between 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 ejection device 100 of the present embodiment will be described with reference to FIG. 12. The flowchart of FIG. 12 is based on a processing algorithm executed by the main control unit 50. The flow here is started when the main control unit 50 receives a job start request from a higher-level device (for example, a personal computer).

In the first step S1, "dry output adjustment process 1" is performed. The dry output adjusting process 1 will be described later.

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

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

In the next step S7, it is determined whether or not the job is completed. If the judgment here is affirmed, the process proceeds to step S9, and if it is denied, the process returns to step S3.

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

Next, the drying output adjusting process 1 will be described with reference to FIG. The flowchart of 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, for example, a standard value. This "standard value" is a theoretically calculated value that allows the recording medium to be dried without excess or deficiency according to the water content of the droplets ejected to the recording medium and the transport speed (drying time) of the recording medium.

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

In the next step T3, a test pattern 1 (see FIG. 4) is formed on the recording medium. Specifically, the droplet ejection head 10a is controlled to eject droplets to a recording medium based on the image information of the test pattern. The image information of the test pattern 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 keeping the drying output at the original value (for example, the standard value of the initial setting).

In the next step T7, 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 test pattern 1 passes through the position facing the humidity sensor 40.

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

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

In the next step T13, the absolute humidity as a reference value is obtained. Specifically, the average value immediately before (for example, 0.6 seconds) of each image unit is used as the 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 above average value (A) -the above reference value (B)" is set as a dry state.

In the next step T17, it is determined whether or not the drying is insufficient. Specifically, when the obtained dry state of the test pattern 1 is negative and the absolute value thereof is the threshold value Dth or more, it is determined that the drying is insufficient, and in other cases, it is determined that the drying is not insufficient. If the judgment here is affirmed, the process proceeds to step T19, and if it is denied, 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 showing 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 (for example, a standard value) so that the absolute value of the drying state becomes less than the threshold value Dth. When step T19 is executed, the flow ends.

In step T21, it is determined whether or not the drying is excessive. Specifically, when the obtained dry state of the test pattern 1 is positive and the absolute value thereof is the threshold value Dth or more, it is determined that the test pattern 1 is excessively dry, and in other cases, it is determined that the dry state is not excessive. If the judgment here is affirmed, the process proceeds to step T23, and if it is denied, the flow ends.

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

As can be seen from the above description, in the present 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 of the present embodiment described above is a humidity sensor 40 (sensor) that detects the state of the atmosphere in the vicinity of the recording medium to which the droplets are attached and conveyed, and the droplets are dried based on the output of the humidity sensor 40. It includes 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 droplet. As a result, the state of the recording medium can be detected with high accuracy.

Further, since the recording medium is conveyed on the transport path including the position where the droplets are ejected and the position facing the humidity sensor 40, an image is formed on the recording medium while the recording medium is conveyed, and the image is dried. In the image forming process, the dry state of the droplet can be detected with high accuracy.

Further, the humidity sensor 40, which is a heat conduction type humidity sensor, can measure humidity, more accurately, the heat conductivity of air, much faster than other types of humidity sensors, so that a moving recording medium can be used. It is possible to quickly determine whether the environment is damp or dry. More specifically, when the droplets ejected to the recording medium are insufficiently dried, 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. The dry state of the ejected droplets can be accurately measured.

On the other hand, the dryness detection unit including the optical sensor disclosed in Patent Document 1 is a unit that optically detects whether or not ink has transferred 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 general picking inspection, and the state of the recording medium cannot be detected accurately.

Further, since the humidity sensor 40 faces the surface opposite to the surface on which the droplets of the recording medium are ejected, it is possible to prevent the recording surface of the recording medium from being soiled or damaged.

Further, the droplets on the recording medium located on the transport path between the sensor device, the transport unit 20 that transports the recording medium on the transport path, and the position where the droplets are ejected and the position facing the humidity sensor 40 are transferred. In the droplet drying system including the drying unit 30 for drying, the dried state of the droplets after drying by the drying unit 30 can be detected with high accuracy.

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

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

Further, a droplet ejection device 100 (image) including a droplet drying system and a printing unit 10 (image forming unit) that ejects droplets to a recording medium located at a position where the droplets are ejected to form an image. In the forming apparatus), it is possible to obtain a recorded image (printed image) in which the image is dried without excess or deficiency.

Further, since the printing unit 10 forms a test pattern on the recording medium for determining the dry state of the droplet, the dry state of the droplet can be detected more accurately.

Further, in the dry state detection method of the present embodiment, the dry state of the droplets is determined based on the 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 detection result in the detection step. Including the step of detecting.

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

Further, the drying output control method of the present embodiment is a drying output control method for controlling the output of the drying unit 30 that dries the droplets discharged to the recording medium conveyed on the predetermined transport path, and is used on the recording medium. Recording is performed based on the steps of drying the discharged droplets in the drying section 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 section 30, and the detection results in the detecting step. It includes 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 droplets ejected to the recording medium can be dried without excess or deficiency.

Further, in the image forming method of the present embodiment, a step of ejecting droplets onto a recording medium located in a first region on a predetermined transport path to form an image, and a recording medium on which the image is formed are first. A step of transporting the image from the region to a second region on the transport path, a step of drying the image on the recording medium located in the second region by the drying unit 30, and a second step of drying the recording medium on which the image is dried. The process of transporting from the region to the third region on the transport path, the 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 results in the detection step. A step of adjusting the output of the drying unit 30 based on the state of the recording medium, a step of ejecting droplets to another recording medium located in the first region, and a step of forming an image. The step of transporting another recording medium on which the image is formed from the first region to the second region, and the drying unit 30 whose output is adjusted to output an image on another recording medium located in the second region. Including the step of drying in. 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) orthogonal to the transport direction of the recording medium. In the example of FIG. 14A, the humidity sensor 40 is located at a total of three positions, two positions corresponding to (opposing) both ends in the width direction of the recording medium and one position corresponding (opposing) to the center in the width direction. They are arranged one by one.

In this case, the dry state of the recording medium can be obtained in a wide range in the Y-axis direction. Therefore, in order to obtain the dry state of many parts of the recording medium, the humidity sensors 40 may be arranged more (four or more) in the Y-axis direction than in the example of FIG. 14A. The arrangement direction of the plurality of humidity sensors 40 is not limited to the Y-axis direction, and in short, the direction may be non-parallel to the transport direction of the recording medium.

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

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

Further, in the example of FIG. 14 (d), the plurality of (for example, three) humidity sensors 40 are not completely orthogonal to the transport direction of the recording medium (hereinafter, also simply referred to as “transport direction”), but are adjacent to each other. The humidity sensor 40 is arranged in a state of being displaced in the transport direction (X-axis direction). For example, in the case of a serial head in which the droplet ejection head is movable in a direction orthogonal to the transport direction (Y-axis direction), the recording material adheres to the recording medium and then passes through a position facing each humidity sensor 40. This is to keep the time until it is fixed. Therefore, the amount of deviation of the recording media of the two adjacent humidity sensors 40 in the transport direction (X-axis direction) is recorded with respect to the operating speed in the direction orthogonal to the transport direction of the droplet ejection head (serial head) (Y-axis direction). The value may be a value obtained by multiplying the ratio of the transport speeds of the media and the distance between the two adjacent humidity sensors 40 in the direction orthogonal to the transport direction (Y-axis direction).

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

When a configuration capable of measuring in a wide range in the Y-axis direction is adopted as in the examples of FIGS. 14 and 15, for example, as shown in FIG. 16, a direction orthogonal to the transport direction of the recording medium (Y-axis direction). ), And a plurality of strip patterns (image portions) having a length equivalent to the width of the recording medium may be used in the transport direction, or as shown in FIG. 17, the transport direction of the recording medium. And 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 significantly from the actual printed image, it is possible to detect the dry state of the image close to the actual use. The test pattern may be something other than the test patterns 1 to 3, and may be, for example, a pattern in which a plurality of image portions are arranged in a staggered pattern.

As described above, in the above embodiment, an example in which a dedicated test pattern is used to detect a dry state is shown. This is effective for confirming the dry state at a predetermined time (for example, periodically) or at a predetermined frequency (predetermined number of copies or predetermined number of jobs), for example. Further, the image processing process in the present embodiment may be started by detecting that the power of the droplet ejection device is turned on, or may be started by separately detecting an external input to the droplet ejection device. As such, the configuration may be such that the user's instruction is waited for.

On the other hand, in order to compensate for a stable image in response to changes in the environment for a short period of time, or to eliminate wasted energy in response to changes in the environment and save energy, use images to continuously dry the image. It is preferable to monitor.

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

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

Then, the state of the atmosphere in the vicinity of the recording medium is detected (step Q9), the value of the above (A) is obtained (step Q11), the value of the above (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 with respect to the actual image as an image formed on the recording medium by the printing unit 10.

As shown in FIG. 15, in the case of the configuration in which the position in the direction orthogonal to the transport direction (Y-axis direction) of the humidity sensor 40 is variable, the difference in the density of the recording material in the actual image on the recording medium is large. The humidity sensor 40 may be moved to the portion.

On the other hand, when the humidity sensor 40 cannot be moved in the Y-axis direction, the difference in the 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. Select the part where is large and record the position information in the X-axis direction. Then, the above (A) and the above (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, the image forming method of Modification 1 will be described with reference to FIG. The flowchart of FIG. 18 is based on a processing algorithm executed by the main control unit 50. The flow here is started when the main control unit 50 receives a job start request from a higher-level device (for example, a personal computer).

In the first step U1, "dry output adjustment process 1" (see FIG. 13) is performed.

In the next step U3, an image is formed on the recording medium. Specifically, the droplet ejection head 10a is controlled to eject droplets to a recording medium based on 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 is initially set or adjusted in the drying output adjusting process 1.

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

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

In step U11, "dry output adjustment process 2" is performed. The dry output adjusting process 2 will be described later.

Next, the drying output adjusting process 2 will be described with reference to FIG. The flowchart of 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 variable, and for example, the air in the vicinity of the portion of the image formed on the recording medium having a high density of recording material may be measured.

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

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

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

In the next step V9, the dry state of the image is obtained. Specifically, "the above average value (A) -the above reference value (B)" is set as a dry state.

In the next step V11, it is determined whether or not the drying is insufficient. Specifically, when the dried state of the obtained image is negative and the absolute value is equal to or higher 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 judgment here is affirmed, the process proceeds to step V13, and if it is denied, 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 showing the correspondence between the dry output and the dry state is stored in the storage unit 70. Therefore, the main control unit 50 raises the drying output from the original value so that the absolute value of the drying state becomes less than the threshold value Dth with reference to this table. When step V13 is executed, the flow ends.

In step V15, it is determined whether or not the drying is excessive. Specifically, when the obtained dry state of the image is positive and the absolute value thereof is the threshold value Dth or more, it is determined that the image is excessively dry, and in other cases, it is determined that the image is not excessively dry. If the judgment here is affirmed, the process proceeds to step V17, and if it is denied, the flow ends.

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

As can be seen from the above description, in the image forming method of the modified example 1, the dry state of the test pattern 1 is first obtained, the dry output is adjusted as necessary, and then the dry state of the image is changed every time an image is formed. In order to adjust the drying output as required, all images from the first image to the last image in one job are appropriate regardless of changes in the surrounding environment (for example, temperature changes, humidity changes, barometric pressure changes, etc.). It can be dried with a high drying output (the recording medium can be dried without excess or deficiency).

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

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

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

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

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

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

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

As can be seen from the above explanation, in the modification 2, the first image is dried with the drying output as the default standard value, but the subsequent images are dried with a more appropriate drying output. Can be dried. In this case, it is not necessary to prepare a test pattern.

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

In the first step Y1, "dry output adjustment process 1" (see FIG. 13) is performed.

In the next step Y3, an image is formed on the recording medium. Specifically, the droplet ejection head 10a is controlled to eject droplets to a recording medium based on 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 is initially set or adjusted in the drying output adjusting process 1.

In the next step Y7, it is determined whether or not the job is completed. If the judgment here is affirmed, the process proceeds to step Y9, and if it is denied, the process proceeds to step Y11.

In step Y9, the transport 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 initial setting or the last adjustment of the drying output. The timekeeping here is performed by the timekeeping unit 80. If the judgment here is affirmed, the process returns to step Y1, and if the judgment is denied, the same judgment is made again.

As can be seen from the above explanation, in the modified example 3, since the drying output adjusting process 1 is first performed and then the drying output adjusting process 1 is performed at predetermined time intervals, the temperature change, the humidity change, and the atmospheric pressure change in the surrounding environment are performed. Even if the above occurs, the drying output can be controlled to an appropriate value.

In step Y11 of the modification example 3, it may be determined whether or not printing of a predetermined number of copies has been completed since the initial setting or the previous adjustment of the dry output.

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

As shown in FIG. 22, the droplet ejection device 200 includes a paper feed tray on which a recording medium (sheet of paper) is loaded, a paper feed roller group for taking out the recording media from the paper feed tray one by one, and the paper feed roller group. A registration roller group arranged on the downstream side of the paper feed roller group, a printing unit 10 arranged on the downstream side of the registration roller group, a drying unit arranged on the downstream side of the printing unit 10, and the drying unit. The humidity sensor 40 arranged on the downstream side of the, the folding roller arranged on the downstream side of the humidity sensor 40, the paper ejection roller pair arranged on the downstream side of the folding roller, and the downstream of the paper ejection roller pair. It is equipped with an output tray arranged on the side.

In the fourth modification, the drying portion includes a selective heating means and a uniform heating means arranged on the downstream side of the selective heating means. The printing unit 10 is arranged on the downstream side (+ X side) of the resist roller group and on the −Z side of the droplet ejection head 10a (opposing the droplet ejection head 10a), and downstream of the recording medium from the paper feed roller group. It has a feed mechanism 10b that feeds to the side. As an example, the feed mechanism 10b has a plurality of rollers whose axial direction is the Y-axis direction, a platen belt (endless belt) hung on the plurality of rollers, and, for example, for sucking and holding a recording medium on the platen belt. It has a suction part such as a suction fan.

In the droplet ejection device 200 of the modified example 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 in the above-described embodiment and the droplet ejection device of each modified example. And it is possible to dry the image at the adjusted dry output.

In Modification 4, it is preferable to form a test pattern (for example, a solid pattern) as small as possible on a recording medium having a size as small as possible from the viewpoint of speeding up and saving resources.
Further, in the modified example 4, the state of the recording medium may be detected by the procedure of the flowchart of FIG. 26 using an actual image instead of the test pattern.

<< Modification 5 >>
FIG. 23 shows a schematic configuration of the droplet ejection device 300 of the modified example 5. In the droplet ejection device 300, the feeding mechanism 10b described in the modified example 4 is added to the droplet ejection device 100 of the above embodiment, and the drying portion is a combination of the selective heating means and the uniform heating means. be.

In the above embodiment and each modification, the dry output is adjusted based on the output change of the humidity sensor 40, but instead, the transfer speed of the recording medium by the transfer unit 20 may be adjusted. .. Specifically, when it is desired to make it drier, the transport speed is slowed down. On the other hand, when the drying is excessive, the transport speed is increased. For example, in the flowchart of FIG. 13, step T19 may be changed to "decrease the transfer speed", and step T23 may be changed to "increase the transfer speed". Further, for example, in the flowchart of FIG. 19, step V13 may be changed to "decrease the transfer speed", and step V17 may be changed to "increase the transfer speed".

In this case, the transport speed control method of the modified example 6 and the image forming method of the modified examples 7 and 8 described below can be performed.

The transport speed control method of the sixth modification is to determine the transport speed of a recording medium that is transported on a predetermined transport path, droplets are discharged in the first region on the transport path, and the recording medium is dried in the second region on the transport path. It is a transfer speed control method for controlling, and is a step of detecting a state of an atmosphere in the vicinity of the recording medium when the recording medium dried in the second region is in the third region on the transport path, and the detection. The step of detecting the state of the recording medium based on the detection result in the step, the transfer speed between the first and second regions based on the state of the recording medium, and the transfer between the second and third regions. Includes the step of adjusting at least one of the speeds.

The image forming method of the modification 7 is a step of ejecting droplets to a recording medium located in a first region on a predetermined transport path to form an image, and a step of forming an image on the recording medium on which an image is formed by a transport unit 20. A step of transporting the image from the region 1 to the second region on the transport path, a step of drying the image on the recording medium located in the second region by the drying unit 30, and a step of drying the image-dried recording medium in the transport unit 20. Based on the steps of transporting from the second region to the third region on the transport path, the step of detecting the state of the atmosphere near the recording medium located in the third region, and the detection results in the detecting step. A step of detecting the state of the recording medium, a step of adjusting the transport speed of the recording medium between the first and second regions by the transport unit 20 based on the state of the recording medium, and a step of adjusting the position in the first region. A step of ejecting droplets to another recording medium to form an image, and another recording medium on which an image is formed are conveyed from a first region to a second region by a transport unit 20 at an adjusted transport speed. And the step of drying the image on another recording medium located in the second region.

The image forming method of the modification 8 is a step of ejecting droplets to a recording medium located in a first region on a predetermined transport path to form an image, and a recording medium on which the image is formed is transferred by a transport unit 20. The step of transporting the image from the first region to the second region on the transport path, the step of drying the image on the recording medium located in the second region, and the step of drying the image-dried recording medium by the transport unit 20 are second. The step of transporting from the region to the third region on the transport path, the step of detecting the state of the atmosphere in the vicinity of the recording medium located in the third region, and the step of detecting the recording medium based on the detection results in the detecting step. A step of detecting the state, a step of adjusting the transport speed of the recording medium between the second and third regions by the transport 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 recording medium on which the image is formed from a first region to a second region by a transport unit 20, and the second step. A step of drying an image on another recording medium located in the region, and a step of transporting the dried recording medium from the second region to the third region at the adjusted transport speed by the transport unit 20. ,including.

Further, the test pattern may be, for example, a single solid pattern elongated in the transport direction of the recording medium. In this case, a plurality of locations in the solid pattern in different transport directions of the recording medium may be regarded as the plurality of solid patterns to obtain a dry state, and the dry output may be adjusted.

Further, in the droplet ejection device of the above embodiment and each modification, an image is formed based on image data from a personal computer or the like, but in addition to this, a scanner for reading the original image is provided and the image is read by the scanner. An image may be formed based on the obtained image data.

Further, in the above embodiment and each modification, the control device 150 of the droplet ejection device 100 detects the dry state of the droplet, but a processing device is separately provided, and the processing device is based on the output of the humidity sensor 40. The dry state of the droplet may be detected.

Further, in the above-described embodiment and each modification, a sheet-shaped recording medium (for example, recording paper) is used as the recording medium on which the droplets are ejected, but the material and shape of the recording medium are not limited to this. .. For example, the material of the recording medium includes paper, plastic, metal, alloy, ceramic, cloth, wood and the like. Further, the recording medium may be a flat one such as a sheet or a plate, as well as a fibrous fluffy one or one having a three-dimensional shape.
Further, for example, a 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 near the substrate. Since the thermal conductivity of the atmosphere changes depending on the concentration of the recording material in this atmosphere, specifically, the concentration of the solvent of the recording material, the concentration of the recording material (state of the recording material) can be determined by measuring the thermal conductivity. Can be detected.

Further, in the above-described embodiment and each modification, the humidity sensor is arranged so as to face the surface opposite to the surface on which the droplets of the recording paper are ejected, but the surface on which the droplets on the recording paper are ejected. It may be arranged so as to face each other. 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 droplet ejection device of the above-described embodiment and each modification, and in short, any image forming apparatus may be used. For example, the image forming apparatus of the present invention may be configured by a coating device for applying a recording material to a recording medium.

Further, although the droplet ejection device of the above embodiment and each modification has the drying portion 30, it does not have to have the drying portion 30. For example, when the present invention is applied to a household droplet ejection device or the like that does not require high-speed transport, it is not necessary to have a drying portion. In this case, for example, the dry state of the droplets ejected on the recording medium due to natural drying is detected by a sensor device including the humidity sensor 40, and the transport speed of the recording medium is controlled based on the detection result to control the droplets. The dry state may be controlled.

Further, the sensor device of the above embodiment is not limited to the usage in the above embodiment and each modification, and can be used, for example, in a recording device, an inspection device for equipment, a component inspection of food, and the like. be.

10 ... Printing unit (image forming unit), 20 ... Transporting unit (conveying device), 30 ... Drying unit (drying device), 40 ... Humidity sensor, 50 ... Main control unit (detection unit), 100 ... Droplet ejection device ( Image forming apparatus), 110 ... Transport condition control unit (part of control means), 120 ... Dry condition control unit (part of control means).

Japanese Unexamined Patent Publication No. 2015-66621

Claims (20)

At least one heat conduction type humidity sensor and the humidity sensor, which are located opposite to the surface of the recording medium on which the recording material is attached to a predetermined surface and detect the state of the atmosphere in the vicinity of the recording medium, and the humidity sensor. A sensor device having a detection unit that detects the state of the recording medium based on the output of
A transport device having a transport roller for transporting the recording medium in the transport direction on a transport path including a position where the recording material is attached and a position of the sensor device facing the humidity sensor.
A drying device for drying the recording material on the recording medium located on the transport path between the attachment position and the opposite position is provided.
The system is characterized in that the sensor device is located between the drying device and the transport roller, and is arranged in the vicinity of the transport roller separated from the drying device. The system according to claim 1, wherein the humidity sensor faces a surface of the recording medium opposite to the surface to which the recording material is attached. The first or second aspect of claim 1 or 2, wherein the at least one humidity sensor is a plurality of humidity sensors arranged on a plane parallel to the predetermined plane and arranged in a direction non-parallel to the transport direction. system. The system according to claim 1 or 2, further comprising a driving unit that moves the humidity sensor on a surface parallel to the predetermined surface and in a direction non-parallel to the transport direction. The system according to any one of claims 1 to 4, further comprising a control means for controlling a dry state of the recording material based on the state of the recording medium detected by the sensor device. The system according to claim 5, wherein the control means controls the drying device based on the state of the recording medium. The system according to claim 5, wherein the control means controls the transport device based on the state of the recording medium. The system according to any one of claims 1 to 7 and the system.
An image forming apparatus including an image forming unit for adhering a recording material to a recording medium located at the adhering position to form an image. The image forming apparatus according to claim 8, wherein the image forming unit forms a test pattern as an image on the recording medium for detecting the state of the recording medium. The image forming apparatus according to claim 9, wherein the test pattern includes a plurality of patterns arranged in a direction parallel to the transport path. The claim is characterized in that the relationship between the length L1 of the image portion of the test pattern in the direction parallel to the transport path and the length L2 of the non-image portion in the direction parallel to the transport path is L1 <L2. Item 10. The image forming apparatus according to Item 10. The image forming apparatus according to claim 11, wherein L2 ≦ 1.5 L1. The invention according to any one of claims 9 to 12, wherein the test pattern is on a plane parallel to the predetermined plane and includes a plurality of patterns arranged in a direction non-parallel to the transport direction. Image forming device. The image according to any one of claims 9 to 13, wherein the test pattern is on a plane parallel to the predetermined plane and includes a pattern extending in a direction non-parallel to the transport direction. Forming device. 8. The detection unit is characterized in that it detects the state of the recording medium based on the output of the humidity sensor with respect to the actual image as the image formed on the recording medium by the image forming unit. The image forming apparatus according to the description. It is an output control method for controlling the output of a drying device that dries a recording material adhering to a predetermined surface of a recording medium conveyed on a predetermined transfer path.
A step of drying the recording material attached to the recording medium with the drying device,
The state of the atmosphere in the vicinity of the recording medium in which the recording material is dried by the drying device, the drying device and the drying device at opposite positions on the opposite side of the surface of the recording medium to which the recording material is attached. The process of detecting with a heat conduction type humidity sensor located in the vicinity of the transfer roller, which is located between the transfer roller and the transfer roller.
A step of detecting the state of the recording medium based on the detection result in the step of detecting, and a step of detecting the state of the recording medium.
An output control method including a step of adjusting the output of the drying device based on the state of the recording medium. Controls the transport speed of a recording medium that is transported on a predetermined transport path, the recording material is adhered to a predetermined surface in a first region on the transport path, and is dried by a drying device in the second region on the transport path. It is a transport speed control method to be performed.
The state of the atmosphere in the vicinity of the recording medium, which has been dried and is located in the third region on the transport path, is changed to the drying device at a position opposite to the surface of the recording medium to which the recording material is attached. , A process of detecting with a heat conduction type humidity sensor located between the drying device and a transport roller located at a distance from the transport roller and provided in the vicinity of the transport roller.
A step of detecting the state of the recording medium based on the detection result in the step of detecting, and a step of detecting the state of the recording medium.
A transport speed including a step of 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. A step of adhering a recording material to a predetermined surface of a recording medium located in a first region on a predetermined transport path to form an image, and a step of forming an image.
A step of transporting the recording medium on which the image is formed from the first region to a second region on the transport path, and
A step of drying the image on the recording medium located in the second region with a drying device,
A step of transporting the recording medium from which the image has been dried from the second region to a third region on the transport path.
The state of the atmosphere in the vicinity of the recording medium located in the third region was separated from the drying device and the drying device at opposite positions on the opposite side of the surface of the recording medium to which the recording material was attached. The process of detecting with a heat conduction type humidity sensor located in the vicinity of the transfer roller located between the position and the transfer roller, and
A step of detecting the state of the recording medium based on the detection result in the step of detecting, and a step of detecting the state of the recording medium.
The step of adjusting the output of the drying device based on the state of the recording medium, and
A step of adhering a recording material to a predetermined surface of another recording medium located in the first region to form an image, and a step of forming an image.
A step of transporting the other recording medium on which the image is formed from the first region to the second region.
An image forming method comprising a step of drying the image on the other recording medium located in the second region with the drying device whose output is adjusted. A step of adhering a recording material to a predetermined surface of a recording medium located in a first region on a predetermined transport path to form an image, and a step of forming an image.
A step of 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.
A step of drying the image on the recording medium located in the second region with a drying device ,
A step of transporting the recording medium from which the image has been dried from the second region to a third region on the transport path by the transport device.
The state of the atmosphere in the vicinity of the recording medium located in the third region was separated from the drying device and the drying device at opposite positions on the opposite side of the surface of the recording medium to which the recording material was attached. The process of detecting with a heat conduction type humidity sensor located in the vicinity of the transfer roller located between the position and the transfer roller, and
A step of detecting the state of the recording medium based on the detection result in the step of detecting, and a step of detecting the state of the recording medium.
A step of adjusting the transfer speed of the recording medium between the first and second regions by the transfer device based on the state of the recording medium, and
A step of adhering a recording material to a predetermined surface of another recording medium located in the first region to form an image, and a step of forming an image.
A step of transporting the other recording medium on which the image is formed from the first region to the second region at the adjusted transport speed.
An image forming method comprising a step of drying the image on the other recording medium located in the second region. A step of adhering a recording material to a predetermined surface of a recording medium located in a first region on a predetermined transport path to form an image, and a step of forming an image.
A step of 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.
A step of drying the image on the recording medium located in the second region with a drying device ,
A step of transporting the recording medium from which the image has been dried from the second region to a third region on the transport path by the transport device.
The state of the atmosphere in the vicinity of the recording medium located in the third region was separated from the drying device and the drying device at opposite positions on the opposite side of the surface of the recording medium to which the recording material was attached. The process of detecting with a heat conduction type humidity sensor located in the vicinity of the transfer roller located between the position and the transfer roller, and
A step of obtaining the state of the recording medium based on the detection result in the detection step, and a step of obtaining the state of the recording medium.
A step of adjusting the transfer speed of the recording medium between the second and third regions by the transfer device based on the state of the recording medium, and
A step of adhering a recording material to a predetermined surface of another recording medium located in the first region to form an image, and a step of forming an image.
A step of transporting the other recording medium on which the image is formed from the first region to the second region by the transport device.
A step of drying the image on the other recording medium located in the second region,
An image forming method comprising a step of transporting the other recording medium from which the image has been dried from the second region to the third region at the adjusted transport speed by the transport device.

Images