Inkjet recording apparatus

Abstract

The invention provides an ink jet recording apparatus. An inkjet recording apparatus includes a transport path for transporting a recording medium, a recording head, at least one humidity measurement unit, and at least one humidified air supply unit. The recording head discharges ink to the recording medium conveyed on the conveyance path. The humidity measuring unit measures the humidity in the vicinity of the recording head. The humidified air supply unit supplies humidified air to the conveyance path. The inkjet recording apparatus supplies the humidified air through the humidified air supply unit when the humidity measured by the humidity measurement unit is equal to or less than a predetermined humidity threshold value. Thus, the generation of ultrafine particles can be suppressed.

Description

Technical Field

[0001] The present invention relates to an inkjet recording device that discharges ink toward a recording medium through a recording head. Background Art

[0002] In the prior art, an image forming device as an inkjet recording device has a conveying path for conveying a recording medium such as paper, and a recording head for discharging ink to the recording medium conveyed on the conveying path, and is used to form an image on the recording medium. After the electrophotographic image forming device forms a toner image on the recording medium, the unfixed toner image is fixed on the recording medium by a fixing component such as a heated fixing roller. However, in the electrophotographic image forming device, since the fixing component is heated to a high temperature, siloxane is released, and the siloxane condenses or polymerizes in the air, thereby generating ultrafine particles (UFP), which becomes a cause of environmental pollution. Therefore, in the image forming device, it is required to suppress the generation of UFP.

[0003] For example, in an image forming apparatus of the prior art, a fixing device has a fixing rotating body, the fixing rotating body has a heating member and a heating member side elastic layer, wherein the heating member heats the sheet material while in contact with the sheet material to which the toner image is transferred; and the heating member side elastic layer supports the heating member. In addition, the control unit has a normal fixing temperature control mode and an ultrafine particle generation temperature control mode, wherein the normal fixing temperature control mode refers to a mode in which the temperature of the heating member is maintained within a predetermined range of a fixing upper limit temperature and a fixing lower limit temperature; and the ultrafine particle generation temperature control mode has a heating state in which the temperature of the heating member is maintained at an ultrafine particle control upper limit temperature that is 10°C higher than the fixing upper limit temperature, and a heating stop state in which the heating of the heating member is stopped. In this way, the generation of UFP by the fixing device is suppressed.

[0004] Alternatively, in an image forming apparatus of the prior art, the apparatus control unit acquires a production quantity status value from a production quantity status value output unit during image formation, acquires and determines a mode switching value from a mode switching value output unit based on the acquired production quantity status value, forms an image in a normal mode when the continuous printing status value acquired from the continuous printing status value output unit is less than the determined mode switching value, and forms an image in the ultrafine particle suppression mode when the continuous printing status value acquired from the continuous printing status value output unit exceeds the determined mode switching value. Furthermore, when the apparatus control unit forms an image in the ultrafine particle suppression mode, the fixing temperature control unit sets the temperature of the fixing device to a lower temperature than that in the normal mode, and the passing speed control unit sets the passing speed of the sheet in the fixing device to a passing speed slower than that in the normal mode. In this way, the generation of UFP is suppressed while maintaining high image formation productivity.

[0005] However, in image forming apparatuses, water molecules decomposed by ozone may become radical initiators as an example of a polymerization reaction of siloxane, and the number of water molecules in the device, that is, humidity, has a significant influence on the amount of UFP generated.

[0006] Therefore, the image forming apparatus in the prior art includes a temperature and humidity detection unit, a heating unit, and a dehumidification unit, wherein the temperature and humidity detection unit detects the temperature and water vapor amount of the air in the space including at least one end of the fixing pressure unit; the heating unit maintains the surface temperature of the fixing pressure unit above the first threshold when heating and pressurizing the medium; and the dehumidification unit dehumidifies the air so that the water vapor amount of the air becomes below the second threshold. Thus, the amount of UFP generated is reduced by reducing the humidity.

[0007] However, in image forming apparatuses such as inkjet recording apparatuses of inkjet type, ultrafine particles (UFP) are formed by a mechanism different from that of electrophotographic image forming apparatuses. When the inkjet recording apparatus prints by inkjet, tiny ink droplets generated when the ink is discharged from the recording head and when the ink lands, and tiny suspended matter released from the ink in the air when the ink dries, become UFP. Therefore, in the inkjet recording apparatus, it is necessary to suppress the amount of UFP generated by a method different from that of the electrophotographic image forming apparatus. Summary of the invention

[0008] Therefore, in view of the above circumstances, an object of the present invention is to suppress the generation of ultrafine particles (UFP) from ink discharged from a recording head.

[0009] The inkjet recording device of the present invention comprises a conveying path for conveying a recording medium, a recording head, at least one humidity measuring unit, and at least one humidified air supply unit. The recording head discharges ink to the recording medium conveyed on the conveying path. The humidity measuring unit measures the humidity near the recording head. The humidified air supply unit supplies humidified air to the conveying path. When the humidity measured by the humidity measuring unit is below a predetermined humidity threshold, the inkjet recording device supplies the humidified air through the humidified air supply unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a cross-sectional view schematically showing an example of a printer according to an embodiment of the present invention.

[0011] Figure 2 This is a flowchart showing an example of the operation of the printer according to one embodiment of the present invention. DETAILED DESCRIPTION

[0012] First, refer to Figure 1 The overall structure of a printer 1 as an inkjet recording device, that is, an image forming apparatus of an inkjet method, will be described. Figure 1 The front side of the paper in FIG. 1 is the front side of the printer 1 . Arrows L, R, U, and Lo indicated appropriately in the respective figures indicate the left side, right side, top side, and bottom side of the printer 1 , respectively.

[0013] like Figure 1 As shown, the printer 1 has a box-shaped printer body 2. A paper feed cassette 3 is accommodated in a pull-out manner at the lower side of the interior of the printer body 2. The paper feed cassette 3 is used to accommodate paper (recording medium). A paper sensor 4 is provided near the paper feed cassette 3. The paper sensor 4 is used to detect paper accommodated in the paper feed cassette 3 or paper fed from the paper feed cassette 3. The paper sensor 4 can detect the surface roughness, thickness and other characteristics of the paper, and determine the type of paper based on the detection result.

[0014] A first conveying path 5 for conveying paper is provided on the right side inside the printer body 2, and a conveying belt 6 (conveying path) is provided above the paper supply cassette 3 on the central side inside the printer body 2, and a recording head 7 is provided above the conveying belt 6. The first conveying path 5 is provided in the range from the paper supply cassette 3 to the conveying belt 6, and a paper supply roller, a conveying roller, a registration roller, etc. for conveying paper to the conveying belt 6 are provided along the conveying direction in which the first conveying path 5 conveys paper.

[0015] The conveyor belt 6 functions as a second conveying path for conveying the paper printed by the recording head 7. The conveyor belt 6 is wound around a driving roller, a driven roller, a tension roller, etc. The conveyor belt 6 is controlled by the control device 18 described below so that the paper on the conveyor belt 6 is conveyed from the right side to the left side as the driving roller rotates, for example, counterclockwise when viewed from the front. In addition, the conveyor belt 6 can be configured to be able to rise and fall in the vertical direction inside the printer body 2, move to a printing position close to the recording head 7 when the printing action is performed, and move to a retreat position away from the recording head 7 when the printing action is not performed.

[0016] As the recording head 7 for discharging ink to print on the paper conveyed by the conveyor belt 6, four recording heads 7K, 7C, 7M, and 7Y corresponding to the four colors of ink, black, cyan, magenta, and yellow, are provided. The recording heads 7K, 7C, 7M, and 7Y are arranged and arranged in sequence from the upstream side (right side) in the conveying direction of the paper above the conveyor belt 6. When performing a printing operation, the recording heads 7K, 7C, 7M, and 7Y face the upper surface of the conveyor belt 6 and discharge black, cyan, magenta, and yellow inks, respectively, onto the paper on the conveyor belt 6.

[0017] In addition, inside the printer body 2, four ink cartridges 8K, 8C, 8M, and 8Y are provided as ink cartridges 8 for storing ink supplied to the recording head 7, and each of the four ink cartridges 8K, 8C, 8M, and 8Y stores inks of four colors, namely, black, cyan, magenta, and yellow. The ink cartridges 8K, 8C, 8M, and 8Y are arranged and arranged in order from the bottom, for example, at the lower left side inside the printer body 2. The ink cartridges 8K, 8C, 8M, and 8Y are stored in respective ink cartridge storage portions (not shown), for example, in a detachable manner, and the ink cartridge storage portion is provided at the lower left side inside the printer body 2.

[0018] Each recording head 7 is connected to each ink cartridge 8 via an ink supply mechanism (not shown), and the ink supply mechanism is composed of a suction pump, a sub-tank, etc. Figure 1 Only the connection between the black recording head 7K and the black ink cartridge 8K is shown, and the connections between the cyan, magenta, and yellow recording heads 7C, 7M, and 7Y and the cyan, magenta, and yellow ink cartridges 8C, 8M, and 8Y are omitted.

[0019] In addition, at least one temperature and humidity measuring unit 9 (humidity measuring unit) and at least one humidified air supply unit 10 are provided on the second conveying path formed by the conveyor belt 6, wherein the temperature and humidity measuring unit 9 measures the temperature and humidity near the recording head 7; and the humidified air supply unit 10 supplies humidified air to the second conveying path. In addition, a UFP sensor 11 for detecting the amount of ultrafine particles (UFP) generated may be provided on the second conveying path.

[0020] The temperature and humidity measuring unit 9 is disposed at a position capable of measuring the temperature and humidity near the recording head 7. In addition, the temperature and humidity measuring unit 9 may have two sensors, a sensor for measuring the temperature near the recording head 7 and a sensor for measuring the humidity. Preferably, the temperature and humidity measuring unit 9 is configured together with the humidified air supply unit 10 to measure the temperature and humidity in the area where the humidified air supply unit 10 supplies humidified air. For example, the temperature and humidity measuring unit 9 is disposed at an upstream position on the upstream side of an opposing position facing the recording head 7 in the conveying direction of the second conveying path. Alternatively, the temperature and humidity measuring unit 9 may be disposed at an opposing position facing the recording head 7, or at a downstream position on the downstream side of an opposing position facing the recording head 7 in the conveying direction of the second conveying path.

[0021] Alternatively, when the humidified air supply unit 10 supplies humidified air at multiple locations, the temperature and humidity measuring unit 9 may be provided corresponding to each location where the humidified air is supplied. For example, the multiple temperature and humidity measuring units 9 may be provided at two or more locations among the upstream position, the opposite position, and the downstream position relative to the recording head 7.

[0022] The humidified air supply unit 10 may be constructed and arranged to discharge humidified air directly into the space of the recording head 7. However, if the humidity near the recording head 7 is too high, the drying speed of the printing surface will be slow, which may cause poor images. In addition, the steam condensed in the air due to the humidified air may sometimes affect the discharge of ink droplets from the recording head 7. In addition, if the humidity is high near the recording head 7 and a humidity gradient is generated in which the humidity decreases as the distance from the recording head 7 is generated, the droplets that are separated from the recording head 7 by the air path may dry and become UFP.

[0023] Therefore, the humidified air supply unit 10 may be configured and arranged to discharge humidified air in an area including ink droplets discharged from the recording head 7. The humidified air supply unit 10 is, for example, provided at an upstream position that is upstream of a position that faces the recording head 7 in the conveying direction of the second conveying path. Alternatively, the humidified air supply unit 10 may be provided at a position that faces the recording head 7, or at a downstream position that is downstream of a position that faces the recording head 7 in the conveying direction of the second conveying path.

[0024] Alternatively, the humidified air supply unit 10 may be arranged to supply humidified air at multiple locations to the recording head 7. For example, multiple humidified air supply units 10 may be provided at two or more locations upstream, opposite, and downstream of the recording head 7 to perform humidification processing at multiple locations.

[0025] In addition, the temperature and humidity measuring unit 9 and the humidified air supply unit 10 may be provided at different positions, or may be provided at the same position as an integrated unit or as separate devices.

[0026] Furthermore, inside the printer body 2, from the left side to the upper side of the conveyor belt 6, a third conveying path 13 is provided for conveying the paper printed by the recording head 7, and a drying device 14, a curl correction device 15, and a discharge roller 16 are provided in the third conveying path 13. On the right side of the printer body 2, a discharge port 17 is formed near the discharge roller 16, and a paper discharge tray (not shown) is provided below the discharge port 17 and protrudes to the right.

[0027] In addition, a control device 18 for controlling each part of the printer 1 is provided in the printer body 2. The control device 18 includes a control unit, which is a computer composed of a CPU, etc., and a storage unit composed of a ROM, a RAM, a HDD, etc. The control unit performs calculation processing according to the control program and control data stored in the storage unit, thereby controlling each part of the printer 1 connected to the control device 18.

[0028] However, in the printer 1 that prints by inkjet method, ultrafine particles (UFP) are sometimes generated in each stage of ink discharge, landing and drying, which becomes a cause of environmental pollution. For example, when ink is discharged from the recording head 7, the droplets scattered when the ink is discharged and the satellite droplets formed after the main droplets dry in the air, thereby generating UFP. When the ink lands on paper, etc., the droplets are scattered due to the main droplets landing on the paper surface, and the droplets dry to generate UFP. When the ink dries on paper, etc., the ink components and water are suspended at the same time when the ink dries, and dry in this state to generate UFP. In particular, the satellite droplets generated by the discharge of ink are involved in the generation of UFP.

[0029] In addition, temperature and humidity have a great influence on the process of ink droplets drying to generate UFP. Generally speaking, if the temperature is high and the humidity is low, the ink droplets dry faster, and if the temperature is low and the humidity is high, the ink droplets dry slower. At this time, when the ink droplets dry slowly under low temperature and high humidity, the droplets reach the paper or the droplets condense (condense) with each other, thereby reducing the amount of UFP generated. On the other hand, when the ink droplets dry quickly under high temperature and low humidity, more droplets dry in the air before condensing, thereby generating more UFP. In addition, when droplet condensation is promoted, since the size of UFP becomes larger, it is easy to collect UFP by filtration, etc.

[0030] That is, it can be seen that during inkjet printing by the printer 1, the amount of UFP generated can be suppressed by increasing the humidity inside the printer body 2, especially the humidity near the recording head 7 that discharges ink. Therefore, in the printer 1 of this embodiment, the generation of UFP is suppressed by controlling the humidity inside the printer body 2.

[0031] The control device 18 controls the supply of humidified air by the humidified air supply unit 10 based on the humidity measured by the temperature and humidity measuring unit 9 .

[0032] First, the control device 18 inputs the humidity (current humidity W) measured by the temperature and humidity measuring unit 9 from the temperature and humidity measuring unit 9, and determines whether the humidity W is a predetermined humidity threshold value W. L Here, the humidity threshold W L The threshold corresponds to the UFP generation amount being less than a predetermined reference value (e.g., a reference value for environmental protection). For example, the control device 18 measures the internal temperature T of the printer body 2 through the temperature and humidity measuring unit 9, and calculates the humidity threshold W based on the multiplication result of the predetermined correction coefficient K1 and the internal temperature T. L .

[0033] Next, when the current humidity W is the humidity threshold W L In the following cases, the control device 18 controls the humidified air supply unit 10 to supply humidified air so that the internal humidity of the printer body 2 exceeds the humidity threshold value W. L Here, the control device 18 uses a predetermined correction coefficient K2 and a humidity threshold value W L , the current humidity W, and the supply amount H of the humidified air supplied by the humidified air supply unit 10 is controlled so as to satisfy the following mathematical formula (1). 1.5×K2×(W L -W)>H>K2×(W L -W)···(1)

[0034] When the humidified air supply unit 10 supplies humidified air, the control device 18 measures and monitors the internal humidity of the printer body 2 through the temperature and humidity measuring unit 9. When the internal humidity exceeds the humidity threshold value W due to the supply of humidified air, the control device 18 L In the case of , the supply of humidified air by the humidified air supply unit 10 is terminated.

[0035] In addition, the control device 18 may determine whether the detection result (UFP generation amount) of the UFP sensor 11 is less than a predetermined reference value (for example, a reference value for environmental protection), and control the humidified air supply unit 10 according to the result. For example, when the UFP generation amount exceeds the reference value, the control device 18 controls the humidified air supply unit 10 to supply humidified air. On the other hand, when the UFP generation amount is less than the reference value, the control device 18 controls the humidified air supply unit 10 to stop supplying humidified air.

[0036] Next, refer to Figure 2 The flowchart will now describe an example of the operation of the printer 1 according to this embodiment.

[0037] First, in the printer 1 , when the control device 18 issues a print job and starts printing, the temperature and humidity measuring unit 9 measures the temperature and humidity as environmental data near the recording head 7 (step S1 ).

[0038] The control device 18 determines whether the measured humidity (current humidity W) exceeds the humidity threshold value (step S2). Here, when the current humidity W is below the humidity threshold value (step S2: No), the control device 18 supplies humidified air to the second conveying path formed by the conveyor belt 6 as a humidification process of the humidified air supply unit 10 (step S3), and then starts printing based on the current print job (step S4).

[0039] On the other hand, when the current humidity W exceeds the humidity threshold value (step S2 : Yes), the control device 18 does not supply humidified air but starts printing based on the current print job (step S4 ).

[0040] When printing starts, the control device 18 controls to convey the paper from the paper feed cassette 3 to the conveyor belt 6 and the recording head 7 via the first conveying path 5 (step S5), and also controls to discharge ink from the recording head 7 to the paper on the conveyor belt 6 to print while conveying the paper via the second conveying path formed by the conveyor belt 6 (step S6). Furthermore, the control device 18 controls to convey the printed paper to the discharge port 17 via the third conveying path 13, to dry the ink printed on the paper as a drying process by the drying device 14, and to correct the curl of the paper as a curl correction process by the curl correction device 15 (step S7).

[0041] Thus, when the printing of the current print job is completed, the control device 18 determines whether the UFP generation amount is less than a predetermined reference value through the UFP sensor 11 (step S8). Here, when the UFP generation amount exceeds the reference value (step S8: No), the control device 18 supplies humidified air to the second conveying path formed by the conveyor belt 6 through the humidified air supply unit 10 (step S9).

[0042] On the other hand, when the UFP generation amount is below the reference value (step S8: yes), the control device 18 determines whether the current printing task is the final printing task (step S10). If it is not the final printing task (step S10: no), it transfers to step S1 and transfers to the next printing task. On the other hand, if it is the final printing task (step S10: yes), the action is terminated.

[0043] As described above, in this embodiment, the printer 1 as an inkjet recording device has a second conveying path (conveying path), a recording head 7, at least one temperature and humidity measuring unit 9 (humidity measuring unit), and at least one humidified air supply unit 10, wherein the second conveying path is composed of a conveying belt 6 for conveying paper (recording medium); the recording head 7 discharges ink to the paper conveyed on the second conveying path; at least one temperature and humidity measuring unit 9 measures the humidity near the recording head 7; and at least one humidified air supply unit 10 supplies humidified air to the second conveying path. When the humidity measured by the temperature and humidity measuring unit 9 is below a predetermined humidity threshold, the control device 18 that controls each unit in the printer 1 supplies humidified air through the humidified air supply unit 10.

[0044] Accordingly, by sufficiently increasing the humidity near the recording head 7, the drying of droplets scattered during ink discharge and satellite droplets formed, droplets scattered during ink landing, and ink components suspended during ink drying in the air can be suppressed and caused to condense, thereby suppressing the generation of ultrafine particles (UFP).

[0045] In addition, in the present embodiment, the humidified air supply unit 10 supplies humidified air to at least one position including an opposing position opposite to the recording head 7, an upstream position on the upstream side of the opposing position opposite to the recording head 7 in the conveying direction of the second conveying path, and a downstream position on the downstream side of the opposing position opposite to the recording head 7 in the conveying direction of the second conveying path.

[0046] This makes it possible to suppress the drying of ink droplets and the like at an appropriate position near the recording head 7 inside the printer body 2 and suppress the generation of ultrafine particles.

[0047] Next, a printer 1 according to a first variation of the present embodiment will be described. In the first variation, the printer 1 has the same structure as the printer 1 of the above embodiment, but is provided with a plurality of humidified air supply units 10. At a plurality of locations where the humidified air supply units 10 supply humidified air, the air may flow along the second conveying path formed by the conveyor belt 6, and thus the humidity may be different.

[0048] Therefore, the control device 18 sets a plurality of humidity thresholds for each of the plurality of humidified air supply units 10. Furthermore, the control device 18 compares the plurality of humidity thresholds with the humidity (current humidity W) measured by the temperature and humidity measuring unit 9, and controls which of the plurality of humidified air supply units 10 supplies humidified air based on the comparison result. Thus, even when droplets fly to a position far from the recording head 7 due to the generation of an air path inside the printer body 2, the droplets can be prevented from drying and the generation of ultrafine particles can be prevented.

[0049] For example, in the printer 1, as the plurality of humidified air supply units 10, the first humidified air supply unit 10a is provided at an upstream position corresponding to the upstream side of the opposing position facing the recording head 7 in the conveying direction of the second conveying path, the second humidified air supply unit 10b is provided at an opposing position facing the recording head 7, and the third humidified air supply unit 10c is provided at a downstream position corresponding to the downstream side of the opposing position facing the recording head 7 in the conveying direction of the second conveying path. In this case, as the plurality of temperature and humidity measuring units 9, the first temperature and humidity measuring unit 9a is provided corresponding to the first humidified air supply unit 10a, the second temperature and humidity measuring unit 9b is provided corresponding to the second humidified air supply unit 10b, and the third temperature and humidity measuring unit 9c is provided corresponding to the third humidified air supply unit 10c.

[0050] As multiple humidity thresholds, the control device 18 sets a first humidity threshold for the supply position of humidified air supplied by the first humidified air supply unit 10a, sets a second humidity threshold for the supply position of humidified air supplied by the second humidified air supply unit 10b, and sets a third humidity threshold for the supply position of humidified air supplied by the third humidified air supply unit 10c.

[0051] In addition, the control device 18 controls the supply of humidified air by the first humidified air supply unit 10a based on the comparison result of the humidity measured by the first temperature and humidity measuring unit 9a and the first humidity threshold value, controls the supply of humidified air by the second humidified air supply unit 10b based on the comparison result of the humidity measured by the second temperature and humidity measuring unit 9b and the second humidity threshold value, and controls the supply of humidified air by the third humidified air supply unit 10c based on the comparison result of the humidity measured by the third temperature and humidity measuring unit 9c and the third humidity threshold value.

[0052] When wind flows from the upstream side to the downstream side in the conveying direction of the second conveying path, the control device 18 increases the humidity threshold in the order of the first humidity threshold corresponding to the upstream position, the second humidity threshold corresponding to the opposite position, and the third humidity threshold corresponding to the downstream position, thereby maintaining the drying speed of the printed surface at an optimal level while optimally suppressing the amount of UFP generated.

[0053] Next, a printer 1 according to a second variation of the present embodiment will be described. In the second variation, the printer 1 has the same structure as the printer 1 of the above embodiment, and the control device 18 sets a multi-level humidity threshold. The control device 18 compares the humidity (current humidity W) measured by the temperature and humidity measuring unit 9 with the multiple humidity thresholds, and controls the supply amount of humidified air supplied by the humidified air supply unit 10 according to the comparison result.

[0054] For example, when the current humidity W is below a relatively low humidity threshold, the control device 18 increases the supply amount of humidified air supplied by the humidified air supply unit 10, and when the current humidity W is below a relatively high humidity threshold, the control device 18 reduces the supply amount of humidified air supplied by the humidified air supply unit 10. In addition, when a plurality of humidified air supply units 10 are provided, the control device 18 may set a multi-level humidity threshold for each of the plurality of humidified air supply units 10.

[0055] Next, a printer 1 according to a third variation of the present embodiment will be described. In the third variation, the printer 1 has the same structure as the printer 1 of the above embodiment, and the control device 18 sets a humidity threshold value according to the type of recording medium such as paper to be printed. The control device 18 controls the supply of humidified air by the humidified air supply unit 10 according to the comparison result between the set humidity threshold value and the humidity (current humidity W) measured by the temperature and humidity measuring unit 9.

[0056] In the printer 1, the behavior of ink such as the permeability to the recording medium when the ink is discharged varies depending on the type of recording medium, and the humidity suitable for drying the ink may vary. Therefore, in order to perform humidification control (humidity control) near the recording head 7 according to the type of recording medium, the control device 18 sets a humidity threshold value corresponding to the humidified air supply unit 10 according to the type of recording medium.

[0057] For example, in the printer 1, when the type of paper (recording medium) to be printed is selected in a print instruction from an external device such as a personal computer or a print instruction from an operation unit (not shown) of the printer 1, the control device 18 functions as a determination unit that determines the type of paper based on such a print instruction. In addition, in the printer 1, the paper sensor 4 detects the paper stored in the paper feed cassette 3 or the paper fed from the paper feed cassette 3 to detect the characteristics of the paper (recording medium) to be printed, and in this case, the control device 18 functions as a determination unit that determines the type of paper based on such paper characteristics.

[0058] Then, the control device 18 sets a humidity threshold value corresponding to the humidified air supply unit 10 according to the type of paper selected by the print instruction or the type of paper based on the paper characteristics detected by the paper sensor 4 .

[0059] For example, the drying speed is faster in paper with higher permeability, so the control device 18 can set the humidity threshold higher. On the other hand, the drying speed is slower in paper with lower permeability, so the control device 18 can set the humidity threshold lower.

[0060] In this embodiment, the case where the structure of the present invention is applied to a printer 1 as an image forming device is described, but in other different embodiments, as long as an inkjet ink supply mechanism is provided, the structure of the present invention can also be applied to other different image forming devices such as copiers, fax machines, multifunction machines, etc.

Claims

1. An inkjet recording device, characterized in that The invention has a conveying path, a recording head, at least one humidity measuring unit and at least one humidified air supply unit, wherein: The conveying path is used to convey the recording medium; The recording head discharges ink toward the recording medium transported on the transport path; The humidity measuring section measures the humidity near the recording head; The humidified air supply unit supplies humidified air to the transport path. When the humidity measured by the humidity measuring unit is equal to or lower than a predetermined humidity threshold, the humidified air supplying unit supplies the humidified air.

2. The inkjet recording device according to claim 1, wherein The humidified air supply unit supplies the humidified air to at least one of a position facing the recording head, an upstream position upstream of the facing position in the conveying direction of the conveying path, and a downstream position downstream of the facing position in the conveying direction.

3. The inkjet recording device according to claim 2, wherein: The plurality of humidified air supply units are arranged corresponding to the facing position, the upstream position, and the downstream position, respectively. The humidity threshold values ​​respectively set for the plurality of humidified air supplying parts are compared with the humidity measured by the humidity measuring part, and based on the comparison result, it is controlled which of the plurality of humidified air supplying parts supplies the humidified air.

4. The inkjet recording device according to claim 1, wherein: The humidity measured by the humidity measuring unit is compared with the humidity threshold values ​​in multiple stages, and the supply amount of the humidified air supplied by the humidified air supply unit is controlled based on the comparison result.

5. The inkjet recording device according to claim 1, wherein: having a determination unit for determining the type of the recording medium, The humidity threshold is set according to the type of the recording medium determined by the determination unit, and supply of the humidified air by the humidified air supply unit is controlled based on a comparison result between the set humidity threshold and the humidity measured by the humidity measurement unit.

Images