Paper humidifying device and image forming system

Abstract

To stably humidify paper throughout the entire humidification job including initial stages of the humidification job.SOLUTION: A paper humidifying device includes a humidifying part that humidifies paper, a water storage tank that stores water to be supplied to the humidifying part, a circulation drive part that circulates water between the water storage tank and the humidifying part, a temperature adjustment part that adjusts the temperature of the water in the water storage tank, and a control part that controls the temperature adjustment operation of the temperature adjustment part and the circulation operation of the circulation drive part so as to perform a temperature adjustment circulation operation that circulates temperature-adjusted water between the water storage tank and the humidifying part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sheet moistening device and an image forming system. [Background technology]

[0002] In the field of electrophotographic image forming devices, a technique is known in which a humidifying unit humidifies paper on which an image has been formed in order to alleviate problems such as paper deformation such as curling, which tends to occur during dry periods, and paper sticking together. The humidifying unit has a pair of humidifying rollers that hold the paper and add moisture (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-56778 Summary of the Invention [Problem to be solved by the invention]

[0004] However, after a certain number of sheets (e.g., 100 sheets) have been humidified, the temperature of the outer surface of the humidifying roller increases due to heat transfer from the sheets, causing the water wettability of the outer surface of the humidifying roller to change. Furthermore, in the initial stages after the start of a humidifying job, the amount of moisture applied to the sheets by the humidifying roller may be too great, causing the sheets to become too wet and wrinkled. In other words, there is a problem in that it is difficult to stably humidify the sheets throughout the entire humidifying job, including the initial stages of the humidifying job.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sheet moisturizing device and an image forming system that can stably moisturize sheets throughout the entire moisturizing job, including the initial stage of the moisturizing job. [Means for solving the problem]

[0006] One aspect of the paper moisturizing device of the present invention is a humidifying unit that includes a humidifying roller that holds and moistens the paper on which an image has been formed; a water storage tank that stores water to be supplied to the humidifying unit; a circulation drive unit that circulates water between the water storage tank and the humidifying unit; a temperature control unit that controls the temperature of the water in the water storage tank; The device is equipped with a control unit that controls the temperature adjustment operation of the temperature adjustment unit and the circulation operation of the circulation drive unit so as to perform a temperature adjustment circulation operation of circulating temperature-adjusted water between the water storage tank and the humidification unit.

[0007] One aspect of the image forming system of the present invention is an image forming device that forms an image on a sheet; The sheet humidifying device is installed downstream of the image forming device. [Effects of the Invention]

[0008] According to the present invention, it is possible to stably perform moisturizing processing on paper throughout the entire moisturizing job, including the initial stage of the moisturizing job. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an image forming system according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the image forming apparatus according to the present embodiment. [Figure 3] FIG. 3 is a schematic diagram showing a part of the sheet moisturizing device according to the present embodiment. [Figure 4] FIG. 4 is a control block diagram of the image forming system according to this embodiment. [Figure 5] FIG. 5 is a diagram showing the relationship between water temperature and time during the initial operation of the sheet moisturizing device. [Figure 6] FIG. 6 is a flowchart illustrating an example of processing for the initial operation of the sheet moisturizing device. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present embodiment will be described below with reference to the drawings. In the specification and claims of this application, the upstream side refers to the upstream side in the paper transport direction, and the downstream side refers to the downstream side in the transport direction. In the drawings, "front" refers to the front direction, "rear" refers to the rear direction, "left" refers to the left direction, "right" refers to the right direction, "up" refers to the up direction, and "down" refers to the down direction.

[0011] The overall configuration of an image forming system 10 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an image forming system 10 according to this embodiment.

[0012] 1, an image forming system 10 according to this embodiment is a system that forms an image on a sheet S and can humidify and post-process the image-formed sheet S. The image forming system 10 includes a tandem image forming apparatus 12, a sheet humidifier 14 installed downstream of the image forming apparatus 12, and a post-processing apparatus 16 installed downstream of the sheet humidifier 14.

[0013] The image forming device 12 is a device that forms an image on a sheet S by electrophotography. The image forming device 12 transports the sheet S on which an image has been formed to a sheet humidifying device 14. The sheet humidifying device 14 is a device that adds moisture to the sheet S on which an image has been formed to perform a humidifying process. The sheet humidifying device 14 transports the sheet S that has been humidified or the sheet S that has not been humidified to a post-processing device 16. The post-processing device 16 performs post-processing on the sheet S that has been humidified or the sheet S that has not been humidified. Examples of post-processing include decurling, stapling, punching, folding, and binding.

[0014] Next, the configuration of the image forming apparatus 12 according to this embodiment will be described with reference to Figures 1 and 2. Figure 2 is a schematic diagram showing the image forming apparatus 12 according to this embodiment.

[0015] As shown in FIGS. 1 and 2, the image forming apparatus 12 includes a box-shaped apparatus main body (apparatus main body for the image forming apparatus) 18, which constitutes the base frame of the image forming apparatus 12. An image reading unit 20 for reading an image of an original is provided at the top of the apparatus main body 18. The image reading unit 20 optically scans an original D placed on a contact glass or an original D transported onto the contact glass. The image reading unit 20 optically reads the scanned image of the original using a CCD (Charge Coupled Device) sensor 22 to generate image data. An image processing unit 24 is also provided at the top of the apparatus main body 18, which performs image processing such as shading correction and compression on the image data from the image reading unit 20.

[0016] An original transport unit 26 called an ADF (Auto Document Feeder) is provided above the image reading unit 20 in the device main body 18. The original transport unit 26 transports an original D set in a document tray onto the contact glass of the image reading unit 20. An operation display unit 28 having functions as both an operation unit and a display unit is provided on the front side (front side) of the upper part of the device main body 18. The operation display unit 28 is configured, for example, with a liquid crystal display (LCD) with a touch screen. The operation display unit 28 has various operation keys such as a numeric keypad and a start key, and as an operation unit, it accepts various input operations by the user. As a display unit, the operation display unit 28 displays various operation screens, image status, and the operating status of each function.

[0017] 2, an image forming section 30 that forms images by electrophotography is provided in the upper part of the apparatus main body 18. The image forming section 30 has four image forming units 32Y, 32M, 32C, and 32K that form images using color toners of Y (yellow), M (magenta), C (cyan), and K (black) components based on image data. The four image forming units 32Y, 32M, 32C, and 32K are arranged in the vertical direction.

[0018] The image forming units 32Y, 32M, 32C, and 32K for the Y, M, C, and K components have the same configuration. For ease of illustration and explanation, common components are denoted by the same reference numerals, and when distinguishing between them, the reference numerals are suffixed with Y, M, C, or K. In Figure 1, only the components of the image forming unit 32Y for the Y component are denoted by reference numerals, and the components of the other image forming units 32M, 32C, and 32K are not denoted by reference numerals.

[0019] The image forming unit 32 includes a photosensitive drum 34, a charging section 36, an exposure section 38, a developing section 40, and a drum cleaning section 42 arranged around the photosensitive drum 34.

[0020] The photoreceptor drum 34 is a negatively charged organic photoreceptor in which an undercoat layer, a charge generating layer, and a charge transport layer are sequentially laminated on the peripheral surface of a conductive cylinder made of, for example, aluminum. The photoreceptor drum 34 is rotated at a constant peripheral speed by the drive of a rotary motor (not shown).

[0021] The charging unit 36 ​​uniformly charges the outer peripheral surface of the photosensitive drum 34 to a negative polarity. The exposure unit 38 emits a laser beam as scanning light to expose and scan the outer peripheral surface of the photosensitive drum 34, thereby forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum 34. The light amount of the laser beam emitted from the exposure unit 38 is modulated according to image data for each of the YMCK colors.

[0022] The developing unit 40 is, for example, a two-component developing unit. The developing unit 40 visualizes the electrostatic latent image on the outer peripheral surface of the photosensitive drum 34 by attaching toner of each color component to the outer peripheral surface of the photosensitive drum 34, thereby forming a toner image. The drum cleaning unit 42 cleans the transfer residual toner remaining on the outer peripheral surface of the photosensitive drum 34 after the primary transfer. The drum cleaning unit 42 has a drum cleaning blade that comes into sliding contact with the outer peripheral surface of the photosensitive drum 34, etc.

[0023] 2, a transfer unit 44 for transferring a toner image onto paper S is provided in the upper part of the device main body 18. The transfer unit 44 has an endless intermediate transfer belt 46, a plurality of support rollers 48, a primary transfer roller 50, a secondary transfer roller 52, and a belt cleaning unit 54.

[0024] The intermediate transfer belt 46 extends in the vertical direction and is stretched over a plurality of support rollers 48. The intermediate transfer belt 46 circulates due to the rotation of the plurality of support rollers 48. At least one of the plurality of support rollers 48 is configured as a drive roller connected to a rotary motor (not shown) so as to move in conjunction with the motor, and the other support rollers 48 are configured as driven rollers (free rollers).

[0025] The primary transfer rollers 50 are disposed on the inner circumferential surface side of the intermediate transfer belt 46, facing the photosensitive drums 34 of each color component. The primary transfer rollers 50 cooperate with the photosensitive drums 34 to pinch the intermediate transfer belt 46. A primary transfer nip CN for transferring a toner image from the photosensitive drums 34 to the intermediate transfer belt 46 is formed between the outer circumferential surface of the primary transfer roller 50 and the outer circumferential surface of the photosensitive drums 34.

[0026] The secondary transfer roller 52 is disposed opposite a predetermined support roller 48 on the outer circumferential surface side of the intermediate transfer belt 46. The secondary transfer roller 52 cooperates with the predetermined support roller 48 to sandwich the intermediate transfer belt 46. A secondary transfer nip TN for transferring a toner image from the intermediate transfer belt 46 to the paper S is formed between the outer circumferential surface of the secondary transfer roller 52 and the outer circumferential surface of the predetermined support roller 48.

[0027] When the intermediate transfer belt 46 passes through the primary transfer nip CN, the toner images on the photosensitive drums 34 are primarily transferred onto the intermediate transfer belt 46, one after the other, in a superimposed manner. Specifically, a primary transfer bias is applied to the primary transfer roller 50, and a charge of the opposite polarity to the toner is applied to the back side of the intermediate transfer belt 46 (the side that contacts the primary transfer roller 50), so that the toner images are electrostatically transferred onto the intermediate transfer belt 46.

[0028] Thereafter, when the paper S passes through the secondary transfer nip TN, the toner image on the intermediate transfer belt 46 is secondarily transferred onto the paper S. Specifically, by applying a secondary transfer bias of the same polarity as the toner to a predetermined support roller 48 and imparting a charge of the same polarity as the toner to the back side of the intermediate transfer belt 46 (the side that abuts against the predetermined support roller 48), the toner image is electrostatically transferred to the paper S, and an image can be formed on the paper S.

[0029] The belt cleaning unit 54 removes untransferred toner remaining on the surface of the intermediate transfer belt 46 after the secondary transfer. The belt cleaning unit 54 has a cleaning blade that comes into sliding contact with the surface of the intermediate transfer belt 46.

[0030] 2, a fixing unit 56 for fixing the toner image to the paper S is provided on the outlet side of the secondary transfer nip TN within the device main body 18. The fixing unit 56 has a heating roller 58, a fixing roller 60, an endless fixing belt 62, and a pressure roller 64.

[0031] Heating roller 58 has a hollow cylindrical core made of, for example, aluminum, iron, or SUS (stainless steel), and a heating device such as a halogen lamp provided inside the core. Fixing roller 60 is provided opposite heating roller 58. Fixing roller 60 has a hollow cylindrical core made of, for example, aluminum, iron, or SUS, and a surface layer made of, for example, silicone rubber or silicone sponge, provided on the outer periphery of the core. Fixing belt 62 is stretched between heating roller 58 and fixing roller 60 and can rotate. Fixing belt 62 has a base material made of, for example, polyimide resin.

[0032] Pressure roller 64 is provided outside fixing belt 62 in a position facing fixing roller 60, and presses against fixing roller 60 with a predetermined fixing load. Pressure roller 64 has a hollow cylindrical core made of, for example, aluminum, iron, or SUS, an elastic layer made of, for example, silicone rubber provided on the outer surface of the core, and a surface layer made of, for example, PFA tubing provided on the surface of the elastic layer. In addition, a fixing nip FN is formed between fixing roller 60 and pressure roller 64 to transport paper S while applying heat and pressure.

[0033] The pressure roller 64 is rotated by the drive of a rotary motor, which causes the fixing belt 62 to rotate accordingly. As the fixing belt 62 rotates, the heating roller 58 and the fixing roller 60 also rotate accordingly. As a result, the paper S is conveyed while being heated and pressurized in the fixing nip FN, and the toner image that has not yet arrived can be fixed to the paper S.

[0034] 2, a paper feed unit 66 for feeding paper S is provided at the bottom of the device main body 18. The paper feed unit 66 has a plurality of paper feed trays 68 that accommodate a plurality of sheets of paper S. Each paper feed tray 68 accommodates a type of paper S that has been preset based on basis weight, size, etc.

[0035] A paper discharge section 70 is provided downstream of the fixing section 56 within the device body 18 for discharging the paper S on which an image has been formed to the outside of the device body 18. The paper discharge section 70 has a pair of paper discharge rollers 72. By rotating the pair of paper discharge rollers 72, the paper S on which an image has been formed can be discharged to the outside of the device body 18.

[0036] As shown in FIG. 2, a main transport path 74 is provided between the paper feed unit 66 and the paper discharge unit 70 inside the device main body 18. The main transport path 74 is a path along which the paper S is transported when a toner image is formed on the front side of the paper S. The main transport path 74 is a path along which the paper S is transported via a plurality of transport roller pairs including a registration roller pair 76, a secondary transfer nip TN, and a fixing nip FN. In addition, a reversing transport path 78 that reverses the paper S is provided near the paper feed unit 66 inside the device main body 18. The reversing transport path 78 is a path along which the paper S is transported when a toner image is formed on the back side of the paper S, and is connected to the main transport path 74.

[0037] The sheets S contained in the paper feed tray 68 are fed one by one from the top and transported toward the secondary transfer nip TN via the main transport path 74. At this time, the pair of registration rollers 76 corrects the inclination of the sheets S and adjusts the transport timing of the sheets S. Then, at the secondary transfer nip TN, the toner image on the intermediate transfer belt 46 is secondarily transferred all at once onto one side (front or back) of the sheets S, and the toner image is fixed to the sheets S at the fixing nip FN. Thereafter, the sheets S on which the image has been formed are discharged from the paper discharge section 70 to the outside of the device main body 18.

[0038] The specific configuration of sheet moisturizing device 14 according to this embodiment will be described with reference to Figures 1 and 3. Figure 3 is a schematic diagram showing a portion of sheet moisturizing device 14 according to this embodiment.

[0039] 1 and 3, sheet moisturizing device 14 according to this embodiment is a device that moisturizes sheet S on which an image has been formed, by adding moisture, as described above. Sheet moisturizing device 14 has a box-shaped device main body (device main body for sheet moisturizing device) 80, which constitutes the base frame of sheet moisturizing device 14. Water used for the moisturizing process is, for example, tap water, which may contain additives such as surfactants.

[0040] 3, a humidifying section 82 that humidifies paper S on which an image has been formed is provided within the device main body 80. The humidifying section 82 has an upper storage section 84, a lower storage section 86, an upper humidifying roller 88, a lower humidifying roller 90, an upper water supply roller 92, a lower water supply roller 94, an intermediate roller 96, and a pumping roller 98.

[0041] The upper reservoir 84 is provided within the device body 80, and stores water used in the humidification process. The upper reservoir 84 extends in the front-to-rear direction, and is configured to maintain a constant water level during the humidification process. The lower reservoir 86 is provided at a lower position within the device body 80 than the upper reservoir 84, and stores water used in the humidification process. The lower reservoir 86 extends in the front-to-rear direction, and is configured to maintain a constant water level during the humidification process.

[0042] The upper humidifying roller 88 is rotatably provided on the left side of the upper reservoir 84 inside the apparatus main body 80, and contacts the image-formed paper S from above to humidify it. The upper humidifying roller 88 rotates clockwise in FIG. 2 by being driven by a rotary motor (not shown). The outer peripheral portion of the upper humidifying roller 88 is capable of retaining water and is made of a hydrophilic resin such as nitrile rubber (NBR). The upper humidifying roller 88 may be configured to be able to come into contact with and separate from the lower humidifying roller 90 by a known mechanism.

[0043] The lower humidifying roller 90 is rotatably provided above the lower reservoir 86 within the apparatus main body 80, and contacts the image-formed sheet S from below to humidify it. The lower humidifying roller 90 is disposed vertically opposite the upper humidifying roller 88, and cooperates with the upper humidifying roller 88 to hold the image-formed sheet S. The lower humidifying roller 90 rotates counterclockwise in FIG. 2 by being driven by a rotary motor (not shown). The outer peripheral portion of the lower humidifying roller 90 is capable of retaining water and is made of a hydrophilic resin such as nitrile rubber. The lower humidifying roller 90 is disposed opposite the lower water supply roller 94, and is configured to be able to come into contact with and separate from the lower water supply roller 94 by a known mechanism. The lower humidifying roller 90 may also be configured to be able to come into contact with and separate from the upper humidifying roller 88 by a known mechanism.

[0044] The upper water supply roller 92 is rotatably provided above the upper humidifying roller 88 inside the device body 80, and supplies water to the outer peripheral portion of the upper humidifying roller 88. The outer peripheral portion of the upper water supply roller 92 is capable of retaining water and is made of a hydrophilic resin such as nitrile rubber. The upper water supply roller 92 is disposed opposite the upper humidifying roller 88 from above and below, and is configured to be able to come into contact with and separate from the upper humidifying roller 88 using a known mechanism. While in contact with the upper humidifying roller 88, the upper water supply roller 92 rotates counterclockwise in FIG. 2 in conjunction with the rotation of the upper humidifying roller 88.

[0045] The lower water supply roller 94 is rotatably disposed between the lower humidifying roller 90 and the lower reservoir 86 within the device body 80, and a portion of the lower water supply roller 94 is immersed in the water in the lower reservoir 86. The lower water supply roller 94 draws up water from the lower reservoir 86 and supplies it to the outer peripheral portion of the lower humidifying roller 90. The outer peripheral portion of the lower water supply roller 94 is capable of retaining water and is made of a hydrophilic resin such as nitrile rubber. The lower water supply roller 94 rotates clockwise in FIG. 2 in conjunction with the rotation of the lower humidifying roller 90 while in contact with the lower humidifying roller 90.

[0046] Intermediate roller 96 is rotatably disposed to the right of upper water supply roller 92 within device body 80, and supplies water to the outer peripheral portion of upper water supply roller 92. The outer peripheral portion of intermediate roller 96 is capable of retaining water and is made of a hydrophilic resin such as nitrile rubber. Intermediate roller 96 rotates clockwise in FIG. 2 in conjunction with the rotation of upper water supply roller 92, while in contact with upper water supply roller 92.

[0047] The pumping roller 98 is rotatably provided between the intermediate roller 96 and the upper reservoir 84 inside the device main body 80, and a portion of the pumping roller 98 is immersed in the water in the upper reservoir 84. The pumping roller 98 pumps up water from the upper reservoir 84 and supplies it to the outer peripheral portion of the intermediate roller 96. The outer peripheral portion of the pumping roller 98 is capable of holding water and is made of a hydrophilic resin such as nitrile rubber. The pumping roller 98 rotates counterclockwise in FIG. 2 in conjunction with the rotation of the intermediate roller 96 while in contact with the intermediate roller 96.

[0048] As the upper humidifying roller 88 rotates due to the drive of the rotary motor, the upper water supply roller 92, the intermediate roller 96, and the pumping roller 98 rotate in unison. The pumping roller 98 then pumps up water from the upper reservoir 84, and the water is supplied from the upper water supply roller 92 to the outer peripheral portion of the upper humidifying roller 88 via the intermediate roller 96. As the lower humidifying roller 90 rotates due to the drive of the rotary motor, the lower water supply roller 94 rotates in unison. The lower water supply roller 94 then pumps up water from the lower reservoir 86, and the lower water supply roller 94 supplies the water to the outer peripheral portion of the lower humidifying roller 90. With water supplied to the outer peripheral portions of the upper humidifying roller 88 and the lower humidifying roller 90, the upper humidifying roller 88 and the lower humidifying roller 90 cooperate to sandwich the sheet S on which an image has been formed, thereby humidifying the sheet S.

[0049] In addition, the humidifying section 82 may have an upper drain roller (not shown) that regulates the amount of water carried on the outer peripheral portion of the upper water supply roller 92, and a lower drain roller (not shown) that regulates the amount of water carried on the outer peripheral portion of the lower water supply roller 94.

[0050] 3, a water storage tank 100 that stores water to be supplied to the upper storage section 84 and the lower storage section 86 is provided below the humidifying section 82 in the device main body 80. The water storage tank 100 is fixed to the device main body 80, but may be detachable from the device main body 80.

[0051] A water level sensor 102 is provided in the water storage tank 100 to detect the water level in the water storage tank 100. Also provided in the water storage tank 100 is a temperature sensor 104 to detect the temperature of the water in the water storage tank 100. The temperature sensor 104 is made of a waterproof thermocouple.

[0052] Instead of providing the temperature sensor 104 inside the water storage tank 100, a temperature sensor 106 may be provided in the upper storage section 84 or the lower storage section 86 to detect the temperature of the water in the upper storage section 84 or the lower storage section 86, and the temperature sensor 106 is made of a waterproof thermocouple. A temperature sensor 108 may be provided near the upper humidifying roller 88 or the lower humidifying roller 90 to detect the temperature of the water on the outer surface of the upper humidifying roller 88 or the lower humidifying roller 90, and the temperature sensor 108 is made of a radiation thermometer. The temperature sensor 108 may indirectly detect the temperature of the water in the water storage tank 100 by detecting the temperature of the water on the outer surface of the upper humidifying roller 88 or the lower humidifying roller 90.

[0053] As shown in FIG. 3, the sheet moisturizing device 14 includes a circulation drive unit 110 that circulates water between the humidifying unit 82 and the water storage tank 100. Specifically, one end of a supply pipe 112 is connected to the water storage tank 100 to supply water to the upper storage unit 84 and the lower storage unit 86. The other end of the supply pipe 112 is bifurcated, and the supply pipe 112 has two branch pipes 112a and 112b. The tip of the branch pipe 112a is connected to the upper storage unit 84, and the tip of the branch pipe 112b is connected to the lower storage unit 86. A pump 114 is disposed on one end of the supply pipe 112 to transport water toward the upper storage unit 84 and the lower storage unit 86.

[0054] One end of a discharge pipe 116 for discharging water from the upper storage section 84 is connected to the upper storage section 84, and the other end of the discharge pipe 116 is connected to the water storage tank 100. One end of a discharge pipe 118 for discharging water from the lower storage section 86 is connected to the lower storage section 86, and the other end of the discharge pipe 118 is connected to the water storage tank 100. Note that a solenoid valve for opening and closing the flow path of the discharge pipe 116, or a flow control valve for adjusting the flow rate in the discharge pipe 116, or the like, may be provided midway along the discharge pipe 116. A solenoid valve for opening and closing the flow path of the discharge pipe 118, or a flow control valve for adjusting the flow rate in the discharge pipe 118, or the like may be provided midway along the discharge pipe 118.

[0055] By driving the pump 114 to transport water toward the upper storage section 84 and the lower storage section 86, water can be supplied from the water storage tank 100 via the supply pipe 112 and its two branch pipes 112a, 112b to the upper storage section 84 and the lower storage section 86. Meanwhile, water can be discharged from the upper storage section 84 and the lower storage section 86 to the water storage tank 100 via the discharge pipes 116, 118 depending on the amount of water supplied to the upper storage section 84 and the lower storage section 86. By continuously repeating the supply of water to the upper storage section 84 and the lower storage section 86 and the discharge of water to the water storage tank 100, water can be circulated between the water storage tank 100 and the humidifying section 82 (the upper storage section 84 and the lower storage section 86).

[0056] A temperature control heater 120 is provided at an appropriate position in the water storage tank 100 as a temperature control unit that controls the temperature of the water in the water storage tank 100. By driving the pump 114 while the temperature control heater 120 controls the temperature of the water in the water storage tank 100 to a predetermined temperature, the temperature-controlled water can be circulated between the water storage tank 100 and the humidifying unit 82 (upper storage unit 84 and lower storage unit 86).

[0057] 3, a supply tank 122 that stores water to replenish the water tank 100 is provided above the water storage tank 100 in the device main body 80. The supply tank 122 is detachable from the device main body 80.

[0058] The paper moisturizing device 14 is equipped with a replenishing unit 124 that replenishing water from the replenishing tank 122 to the water storage tank 100 by using a hydraulic head difference. Specifically, one end of a replenishing pipe 126 for replenishing water to the water storage tank 100 is connected to the replenishing tank 122, and the other end of the replenishing pipe 126 is connected to the water storage tank 100. In addition, a solenoid valve 128 that opens and closes the flow path of the replenishing pipe 126 is provided midway along the replenishing pipe 126.

[0059] By opening the flow path of the supply pipe 126 by the opening operation of the solenoid valve 128, it is possible to supply water from the supply tank 122 to the water storage tank 100 via the supply pipe 126. On the other hand, by closing the flow path of the supply pipe 126 by the opening / closing operation of the solenoid valve 128, it is possible to stop the supply of water to the water storage tank 100.

[0060] 3, a drain tank 130 that stores water discharged from the water storage tank 100 is provided below the water storage tank 100 within the device main body 80. The drain tank 130 is detachable from the device main body 80.

[0061] The paper moisturizing device 14 is equipped with a drainage unit 132 that drains water from the water storage tank 100 to the drainage tank 130 by using a hydraulic head difference. Specifically, one end of a drainage pipe 134 for discharging water into the drainage tank 130 is connected to the water storage tank 100, and the other end of the drainage pipe 134 is connected to the drainage tank 130. In addition, a solenoid valve 136 that opens and closes the flow path of the drainage pipe 134 is provided midway along the drainage pipe 134.

[0062] By opening the flow path of the drain pipe 134 by the opening operation of the solenoid valve 136, water can be drained from the water storage tank 100 to the drain tank 130 via the drain pipe 134. On the other hand, by closing and opening the solenoid valve 136 to close the flow path of the drain pipe 134, the drainage of water to the drain tank 130 can be stopped.

[0063] 1, a decurler unit 140 that corrects curling of paper sheet S is provided to the left of the humidifier unit 82 inside the device body 80. A paper inverting unit 142 that inverts paper sheet S delivered from the humidifier unit 82 is provided below the decurler unit 140 inside the device body 80. A purge unit 144 that stores paper sheet S that is discharged from the device body 80 due to a malfunction such as a jam is provided at the top of the device body 80.

[0064] The control configuration of image forming system 10 according to this embodiment will be described with reference to Figures 3 to 5. Figure 4 is a control block diagram of image forming system 10 according to this embodiment. Figure 5 is a diagram showing the relationship between water temperature and time during the initial operation of sheet moisturizing device 14.

[0065] 4, the image forming system 10 includes a control unit 146 that controls the image processing unit 24, the image forming unit 30, the transfer unit 44, the fixing unit 56, the paper feed unit 66, the humidifying unit 82, the circulation drive unit 110, the temperature control heater 120, the supply unit 124, the drainage unit 132, etc. The control unit 146 is responsible for controlling the entire image forming system 10. The control unit 146 includes a CPU (Central Processing Unit) 148, a ROM (Read Only Memory) 150, and a RAM (Random Access Memory) 152. The control unit 146 is connected to a storage unit 154, a communication unit 156, the water level sensor 102, the temperature sensor 104, etc.

[0066] The CPU 148 performs overall control of the overall operation of the image forming system 10. The CPU 148 reads out various control programs and setting data stored in the ROM 150, stores them in the RAM 152, and executes the programs to perform various arithmetic processing. The RAM 152 provides the CPU 148 with working memory space and stores temporary data. The CPU 148 also references various data stored in a storage unit 154 when performing various arithmetic processing. The storage unit 154 is configured, for example, with a non-volatile semiconductor memory or a hard disk drive.

[0067] Control unit 146 transmits and receives various data to and from an external device (e.g., a personal computer) connected to a communication network such as a LAN (Local Area Network) or WAN (Wide Area Network) via communication unit 156. Control unit 146 receives image data transmitted from, for example, an external device, and forms a toner image on paper S based on this image data (input image data). Communication unit 156 is configured by, for example, a communication control card such as a LAN card.

[0068] 3 to 5, when executing a humidification job to humidify paper S on which an image has been formed, control unit 146 controls a rotation motor (not shown) of humidification unit 82 so as to synchronously rotate upper humidification roller 88 and lower humidification roller 90. Furthermore, when executing the humidification job, control unit 146 controls the circulation operation of circulation drive unit 110.

[0069] The control unit 146 controls the temperature control operation of the temperature control heater 120 and the circulation operation of the circulation drive unit 110 so as to perform an initial operation as a temperature control circulation operation of the sheet humidifier 14 before a humidification job. The initial operation is a warm-up operation in which temperature-controlled water is circulated between the water storage tank 100 and the humidifier unit 82 (the upper reservoir unit 84 and the lower reservoir unit 86). The water circulation speed in the initial operation is set to a higher speed than the water circulation speed during a humidification job. The control unit 146 also starts the temperature control operation of the temperature control heater 120 at the same time as starting the circulation operation of the circulation drive unit 110. The control unit 146 may also start the circulation operation of the circulation drive unit 110 a predetermined time after starting the temperature control operation of the temperature control heater 120. Furthermore, when performing the initial operation, the control unit 146 controls the rotation motor of the humidifier unit 82 so as to rotate the upper humidifying roller 88 and the lower humidifying roller 90 in synchronization.

[0070] When performing an initial operation after powering on the image forming system 10, the control unit 146 controls the temperature adjustment operation of the temperature control heater 120 based on the detection results of the temperature sensor 104, etc., so that the water temperature becomes a predetermined high temperature T1. "After powering on the image forming system 10" is an example of a case where the detected temperature is equal to or lower than a predetermined temperature. The predetermined high temperature T1 is a temperature higher than a predetermined reference temperature T2, which is, for example, 40°C in this embodiment. The predetermined reference temperature T2 is a temperature set in advance to ensure sufficient water wettability of the outer circumferential surfaces of the upper humidifying roller 88 and the lower humidifying roller 90, which is, for example, 30±5°C (25°C or higher and 35°C or lower) in this embodiment.

[0071] The control unit 146 controls the temperature adjustment operation of the temperature control heater 120 based on the detection results of the temperature sensor 104, etc., so that the predetermined high temperature T1 is maintained until a predetermined time has elapsed after the temperature of the water reaches the predetermined high temperature T1. The control unit 146 controls the temperature adjustment operation of the temperature control heater 120 based on the detection results of the temperature sensor 104, etc., so that the water temperature becomes a predetermined reference temperature T2 after the predetermined high temperature T1 is maintained until the predetermined time has elapsed.

[0072] Instead of controlling the temperature regulation operation of the temperature control heater 120 based on the detection results of the temperature sensor 104 or the like, the control unit 146 may control the temperature control heater 120 to switch ON / OFF at predetermined time intervals.

[0073] 3 and 4, the control unit 146 controls the replenishing operation of the replenishing unit 124 based on the detection result from the water level sensor 102. Specifically, when the water level in the water storage tank 100 falls below a predetermined reference water level, the control unit 146 opens the flow path of the replenishing pipe 126 by opening the solenoid valve 128. After opening the flow path of the replenishing pipe 126, when the water level in the water storage tank 100 reaches the predetermined reference water level, the control unit 146 closes the flow path of the replenishing pipe 126 by closing the solenoid valve 128. The predetermined reference water level is a water level required to circulate water between the water storage tank 100 and the humidifying unit 82 (upper storage unit 84 and lower storage unit 86).

[0074] As shown in FIGS. 3 and 4 , the control unit 146 executes a drain operation of the drain unit 132 when a predetermined period of time has elapsed since the previous humidification job. Specifically, when a predetermined period of time has elapsed since the previous humidification job, the control unit 146 opens the flow path of the drain pipe 134 by opening the solenoid valve 136. After opening the flow path of the drain pipe 134, the control unit 146 closes the flow path of the drain pipe 134 by closing the solenoid valve 136 when the water level in the water storage tank 100 reaches a predetermined low water level. The predetermined period of time refers to the period of time during which the water in the water storage tank 100 becomes spoiled and the water storage tank 100 needs to be drained, such as four or six months. The predetermined low water level refers to the water level when the water in the water storage tank 100 has been drained to a certain extent, and includes the zero water level.

[0075] After the drainage operation of the drainage unit 132 is completed, the control unit 146 executes the refilling operation of the refilling unit 124. Specifically, after the drainage operation of the drainage unit 132 is completed, the control unit 146 opens the flow path of the refilling pipe 126 by opening the electromagnetic valve 128. After opening the flow path of the refilling pipe 126, when the water level in the water storage tank 100 reaches a predetermined reference water level, the control unit 146 closes the flow path of the refilling pipe 126 by closing the electromagnetic valve 128.

[0076] 3 and 4, the control unit 146 may execute a refilling operation of the refilling unit 124 so as to refill the water storage tank 100 with a predetermined amount of water after the drainage operation of the drainage unit 132 is completed. Specifically, after the drainage operation of the drainage unit 132 is completed, the control unit 146 opens the flow path of the refilling pipe 126 by opening the solenoid valve 128. After opening the flow path of the refilling pipe 126, when the water level in the water storage tank 100 reaches a water level corresponding to the predetermined water amount, the control unit 146 closes the flow path of the refilling pipe 126 by closing the solenoid valve 128. The predetermined amount of water is the amount of water required to wash the upper storage unit 84, the lower storage unit 86, the supply pipe 112, and the discharge pipes 116 and 118.

[0077] The control unit 146 may control the circulation drive unit 110 to circulate the predetermined amount of water between the water storage tank 100 and the humidifier unit 82 (upper storage unit 84 and lower storage unit 86) for a predetermined period of time after replenishing the water storage tank 100 with a predetermined amount of water. Furthermore, the control unit 146 may cause the drainage unit 132 to perform the drainage operation again after circulating the predetermined amount of water between the water storage tank 100 and the humidifier unit 82 for a predetermined period of time. The control unit 146 may cause the replenishing unit 124 to perform the replenishing operation again after the drainage unit 132 has completed the second drainage operation.

[0078] Next, an example of the processing of the initial operation (warming-up operation) of sheet moisturizing device 14 by control unit 146 will be described with reference to Figures 3, 4, and 6. Figure 6 is a flowchart for explaining an example of the processing of the initial operation of sheet moisturizing device 14.

[0079] 3, 4, and 6, the control unit 146 determines whether a predetermined period of time has elapsed since the previous humidification job (step S101 in FIG. 6). Next, if the predetermined period of time has not elapsed since the previous humidification job (NO in step S101 in FIG. 6), the control unit 146 determines whether the water level in the water storage tank 100 is equal to or higher than a predetermined reference water level based on the detection result of the water level sensor 102 (step S102 in FIG. 6). Then, if the water level in the water storage tank 100 is equal to or higher than the predetermined reference water level (YES in step S102 in FIG. 6), the control unit 146 executes the temperature adjustment operation of the temperature adjustment heater 120 and the circulation operation of the circulation drive unit 110 (step S103 in FIG. 6).

[0080] As shown in FIGS. 3, 4, and 6, if the water level in the water storage tank 100 is below a predetermined reference water level (NO in step S102 in FIG. 6), the control unit 146 starts the replenishing operation of the replenishing unit 124 (step S104 in FIG. 6). Then, the control unit 146 determines whether the water level in the water storage tank 100 has reached the predetermined reference water level based on the detection result of the water level sensor 102 (step S105 in FIG. 6). If the water level in the water storage tank 100 has reached the predetermined reference water level (YES in step S105 in FIG. 6), the control unit 146 stops the replenishing operation of the replenishing unit 124 (step S106 in FIG. 6). Thereafter, the control unit 146 executes the temperature adjustment operation of the temperature adjustment heater 120 and the circulation operation of the circulation drive unit 110 (step S107 in FIG. 6).

[0081] 3, 4, and 6, if a predetermined period of time has passed since the previous humidification job (YES in step S101 in FIG. 6), the control unit 146 starts the drainage operation of the drainage unit 132 (step S108 in FIG. 6). Next, the control unit 146 determines whether the water level in the water storage tank 100 has fallen below a predetermined low water level based on the detection result of the water level sensor 102 (step S109 in FIG. 6). Then, if the water level in the water storage tank 100 has fallen below the predetermined low water level (YES in step S109 in FIG. 6), the control unit 146 stops the drainage operation of the drainage unit 132 (step S110 in FIG. 6).

[0082] After step S110 in FIG. 6 is completed, the control unit 146 starts the replenishing operation of the replenishing unit 124 (step S111 in FIG. 6). Then, the control unit 146 determines whether the water level in the water storage tank 100 has reached a predetermined reference water level based on the detection result of the water level sensor 102 (step S112 in FIG. 6). If the water level in the water storage tank 100 has reached the predetermined reference water level (YES in step S112 in FIG. 6), the control unit 146 stops the replenishing operation of the replenishing unit 124 (step S113 in FIG. 6). Thereafter, the control unit 146 executes the temperature adjustment operation of the temperature adjustment heater 120 and the circulation operation of the circulation drive unit 110 (step S114 in FIG. 6).

[0083] In the configuration of the sheet moisturizing device 14 according to this embodiment, the control unit 146 controls the temperature adjustment operation of the temperature adjustment heater 120 and the circulation operation of the circulation drive unit 110 to perform an initial operation of circulating temperature-adjusted water between the water storage tank 100 and the humidifying unit 82. Therefore, as the upper humidifying roller 88 rotates, temperature-adjusted water is supplied from the upper water supply roller 92 to the outer peripheral portion of the upper humidifying roller 88 via the pumping roller 98 and the intermediate roller 96. As the lower humidifying roller 90 rotates, temperature-adjusted water is supplied from the lower water supply roller 94 to the outer peripheral portion of the lower humidifying roller 90. This increases the temperature of the outer peripheral surfaces of the upper humidifying roller 88 and the lower humidifying roller 90, thereby improving the water wettability of the outer peripheral surfaces of the upper humidifying roller 88 and the lower humidifying roller 90. As a result, even in the early stages of a humidification job, the water wettability of the outer surfaces of the upper humidifying roller 88 and the lower humidifying roller 90 can be sufficiently ensured, and the water film formed on the outer surfaces of the upper humidifying roller 88 and the lower humidifying roller 90 can be thinned.

[0084] Therefore, according to the sheet moisturizing device 14 of this embodiment, it is possible to stably moisturize the sheet S throughout the entire moisturizing job, including the initial stage of the moisturizing job. In particular, when the control unit 146 executes the initial operation before the moisturizing job, the above-mentioned effect can be further enhanced.

[0085] Furthermore, with the configuration of the sheet moisturizing device 14 according to this embodiment, the control unit 146 controls the temperature adjustment operation of the temperature adjustment heater 120 based on the detection results of the temperature sensor 104, etc. Therefore, water whose temperature has been adjusted to a predetermined temperature, such as a predetermined high temperature T1 or a predetermined reference temperature T2, can be circulated between the water storage tank 100 and the humidifying unit 82.

[0086] Therefore, according to the sheet moisturizing device 14 of this embodiment, the temperature control heater 120 can perform the temperature control process with high precision.

[0087] Furthermore, in the configuration of the sheet moisturizing device 14 according to this embodiment, when the image forming system 10 is powered on and an initial operation is performed, the control unit 146 controls the temperature control operation of the temperature control heater 120 so that the water temperature reaches a predetermined high temperature T1. As a result, the temperatures of the outer circumferential surfaces of the upper humidifying roller 88 and the lower humidifying roller 90 increase in a short period of time, thereby quickly increasing the water wettability of the outer circumferential surfaces of the upper humidifying roller 88 and the lower humidifying roller 90. In particular, if the water temperature is maintained at the predetermined high temperature T1 for a predetermined time after it reaches the predetermined high temperature T1, the water wettability of the outer circumferential surfaces of the upper humidifying roller 88 and the lower humidifying roller 90 can be stably increased.

[0088] Therefore, according to the sheet humidifier 14 of this embodiment, the time required for the initial operation of the sheet humidifier 14 can be shortened.

[0089] Furthermore, with the configuration of sheet moisturizing device 14 according to this embodiment, control unit 146 starts the circulation operation of circulation drive unit 110 and simultaneously starts the temperature control operation of temperature control heater 120. As a result, the temperatures of the outer peripheral surfaces of upper moisturizing roller 88 and lower moisturizing roller 90 increase in a short period of time, and the water wettability of the outer peripheral surfaces of upper moisturizing roller 88 and lower moisturizing roller 90 can be improved in a short period of time.

[0090] Therefore, according to the sheet humidifier 14 of this embodiment, the time required for the initial operation of the sheet humidifier 14 can be shortened.

[0091] Furthermore, with the configuration of sheet moisturizing device 14 according to this embodiment, control unit 146 controls the replenishing operation of replenishing unit 124 based on the detection results from water level sensor 102. This allows the water level in water storage tank 100 to be maintained at a predetermined reference water level. In other words, water storage tank 100 can store only the amount of water necessary to circulate water between water storage tank 100 and humidifying unit 82 (the amount of water necessary for circulation).

[0092] Therefore, with the sheet moisturizing device 14 according to this embodiment, the temperature of only the amount of water required for circulation can be controlled by the temperature control heater 120, and the power consumption of the temperature control heater 120 can be reduced.

[0093] Furthermore, with the configuration of sheet moisturizing device 14 according to this embodiment, control unit 146 executes the drainage operation of drainage unit 132 when a predetermined period of time has elapsed since the previous moisturizing job. This prevents spoiled water from being stored in water storage tank 100 for a long period of time, and prevents the viscosity of the water in water storage tank 100 from increasing. This allows low-viscosity water to be supplied to the outer peripheral portions of upper moisturizing roller 88 and lower moisturizing roller 90.

[0094] Therefore, with the sheet moisturizing device 14 according to this embodiment, the water wettability of the outer peripheral surfaces of the upper moisturizing roller 88 and the lower moisturizing roller 90 is increased, and the sheet S can be moisturized more stably.

[0095] Furthermore, in the configuration of sheet moisturizing device 14 according to this embodiment, control unit 146 controls circulation drive unit 110 to circulate a predetermined amount of water between water storage tank 100 and humidifier unit 82 for a predetermined period of time after replenishing water with the predetermined amount of water. This allows the predetermined amount of water to be used to clean the interiors of upper storage unit 84, lower storage unit 86, supply pipe 112, and discharge pipes 116 and 118.

[0096] Therefore, according to the sheet humidifier 14 of this embodiment, the ease of maintenance of the sheet humidifier 14 can be improved.

[0097] Although the present embodiment has been specifically described above, the present invention is not limited to the specific embodiment described above. Various modifications and changes to the specific examples described in the above embodiment are possible within the scope of the gist of the present invention as defined in the claims. [Industrial Applicability]

[0098] The present invention is useful as a sheet moisturizing device and an image forming system that can stably moisturize sheets throughout an entire moisturizing job. [Explanation of symbols]

[0099] 10. Image forming system 12 Image forming device 14 Paper humidifier 16 Aftertreatment device 18 Device body 20 Image reading unit 22 CCD sensors 24 Image processing section 26 Document transport section 28 Operation display section 30 Image forming unit 32 Image forming unit 32Y Image forming unit 32M Image Forming Unit 32C Image Formation Unit 32K Image Formation Unit 34 Photosensitive drum 36 Charging section 38 Exposure section 40 Development Unit 42 Drum Cleaning Section 44 Transcription unit 46 Intermediate transfer belt 48 Support Roller 50 Primary transfer roller 52 Secondary transfer roller 54 Belt cleaning section 56 Fixing section 58 heated roller 60 Fixing roller 62 Fixing belt 64 Pressure Roller 66 Paper feed section 68 Paper tray 70 Paper output section 72 Paper ejection roller pair 74 Main transport route 76 Registration Roller Pair 78 Reversing conveyance path 80 Device body 82 Humidification unit 84 Upper Reservoir 86 Lower reservoir 88 Upper humidifying roller 90 Lower Moisturizing Roller 92 Upper water supply roller 94 Lower water supply roller 96 Intermediate Roller 98 Pumping roller 100 Water Tank 102 Water level sensor 104 Temperature Sensor 106 Temperature Sensor 108 Temperature Sensor 110 Circulation drive unit 112 Supply piping 112a Branch piping 112b Branch piping 114 Pump 116 Discharge piping 118 Discharge piping 120 Temperature control heater (temperature control section) 122 Resupply Tank 124 Supply Department 126 Supply piping 128 Solenoid valve 130 Drainage Tank 132 Drainage section 134 Drainage piping 136 Solenoid valve 140 Decala Department 142 Paper reversing unit 144 Purge section 146 Control Unit 148 CPU 150 ROM 152 RAM 154 Storage section 156 Communications Department CN Primary Transfer Nip TN Secondary Transfer Nip FN Fixing Nip S paper D Manuscript

Claims

1. a humidifying unit that includes a humidifying roller that holds and moistens the paper on which an image has been formed; a water storage tank that stores water to be supplied to the humidifying unit; a circulation drive unit that circulates water between the water storage tank and the humidifying unit; a temperature control unit that controls the temperature of the water in the water storage tank; and a control unit that controls the temperature adjustment operation of the temperature adjustment unit and the circulation operation of the circulation drive unit so as to perform a temperature adjustment circulation operation of circulating temperature-adjusted water between the water storage tank and the humidification unit. Paper moistening device.

2. Equipped with a temperature sensor to detect the water temperature, The control unit controls the temperature adjustment operation of the temperature adjustment unit based on the detection result of the temperature sensor. The sheet moistening device according to claim 1.

3. The temperature sensor is provided in the water storage tank. The sheet moistening device according to claim 2.

4. The temperature sensor is provided in a part of the humidifying unit or in the vicinity thereof. The sheet moistening device according to claim 2.

5. the control unit executes the temperature control circulation operation before a humidification job for humidifying paper on which an image has been formed. The sheet moistening device according to claim 1.

6. When the detected temperature is equal to or lower than a predetermined temperature and the temperature control circulation operation is to be performed, the control unit controls the temperature control operation of the temperature control unit so that the water temperature becomes a high temperature that is higher than a reference temperature. The sheet moistening device according to claim 2.

7. The control unit controls the temperature adjustment operation of the temperature adjustment unit so that the high temperature is maintained until a predetermined time has elapsed after the temperature of the water reaches the high temperature. The sheet moistening device according to claim 6.

8. the control unit controls the temperature adjustment operation of the temperature adjustment unit so that the temperature of the water becomes the reference temperature after maintaining the high temperature until the predetermined time has elapsed. The sheet moistening device according to claim 7.

9. The control unit starts the circulation operation of the circulation drive unit and simultaneously starts the temperature adjustment operation of the temperature adjustment unit. The sheet moistening device according to claim 1.

10. a water level sensor for detecting the water level in the water storage tank; a refill tank for storing water to refill the water storage tank; a replenishing unit that replenishing water from the replenishing tank to the water storage tank, The control unit controls the replenishing operation of the replenishing unit based on the detection result from the water level sensor. The sheet moistening device according to claim 1.

11. a drainage tank for storing water discharged from the water storage tank; a drainage unit that drains water from the water storage tank to the drainage tank, the control unit executes a draining operation of the drain unit when a predetermined period has elapsed since the previous humidification job, and executes a replenishing operation of the replenishing unit after the draining operation of the drain unit is completed. The sheet moistening device of claim 10.

12. a drainage tank for storing water discharged from the water storage tank; a drainage unit that drains water from the water storage tank to the drainage tank, The control unit When a predetermined period of time has elapsed since the previous humidification job, the drainage unit performs a drainage operation, and after the drainage unit has completed the drainage operation, the supplying unit is controlled to supply a predetermined amount of water to the water storage tank, and thereafter the circulation drive unit is controlled to circulate the predetermined amount of water between the water storage tank and the humidification unit for a predetermined time. The sheet moistening device of claim 10.

13. The control unit After the predetermined amount of water has been circulated between the water storage tank and the humidifying unit for the predetermined time, the draining operation of the draining unit is performed again, and after the second draining operation of the draining unit is completed, the replenishing operation of the replenishing unit is performed again. The sheet moistening device of claim 12.

14. an image forming device that forms an image on a sheet; The sheet moisturizing device according to any one of claims 1 to 13 is installed downstream of the image forming device. Imaging system.

Images