Abstract: A sheet-conveying device contains a first linear sheet-conveying path on which the sheet is conveyed, a curved sheet-conveying path connecting the first linear sheet-conveying path and a second linear sheet-conveying path connecting the curved sheet-conveying path. A curved conveying guide is provided at only an outside of a curved sheet-conveying route. Conveying guide rollers are provided at an upstream side of the curved conveying guide. The conveying guide rollers contain a driving roller which is arranged at outside of the curved sheet-conveying path and a driven roller which is arranged at inside of the curved sheet-conveying path. The driven roller has a diameter more than that of the driving roller. The driven roller also has hardness less than that of the driving roller.

Abstract: A sheet-conveying device contains a first linear sheet-conveying path on which the sheet is conveyed, a curved sheet-conveying path connecting the first linear sheet-conveying path and a second linear sheet-conveying path connecting the curved sheet-conveying path. A curved conveying guide is provided at only an outside of a curved sheet-conveying route. Conveying guide rollers are provided at an upstream side of the curved conveying guide. The conveying guide rollers contain a driving roller which is arranged at outside of the curved sheet-conveying path and a driven roller which is arranged at inside of the curved sheet-conveying path. The driven roller has a diameter more than that of the driving roller. The driven roller also has hardness less than that of the driving roller.

Abstract: A paper sheet humidifying device including a humidifying roller to convey a paper sheet and apply water to the paper sheet; a water supply roller to supply water to the humidifying roller; a water supply plate to contain the water for dipping the water supply roller, and to eject excessive water by overflowing; a water feeding section to feed the water to the water supply plate; a drain tank to receive the water ejected from the water supply plate, the drain tank comprising a drain outlet to eject the received water; a water level sensor to output a signal when a water level in the drain tank reaches a prescribed level; and a controller to execute a control to prevent overflowing of the water from the drain tank based on the signal from the water level sensor.

Abstract: A sheet humidifier which executes a humidifying process to a sheet, the sheet humidifier including: a pair of humidifying rollers each of which has a first surface layer formed of rubber containing plasticizer, the pair of humidifying rollers nipping and conveying the sheet; and two water supply rollers each of which has a second surface layer formed of rubber containing the same kind of plasticizer as the plasticizer of the first surface layer, the two water supply rollers contacting each of the pair of humidifying rollers and supplying water to the each of the pair of humidifying rollers, wherein a hardness of the first surface layer is higher than the second surface layer.

Abstract: A sheet humidifying device includes a pair of humidifying rollers which form a nip portion by pressure contacting against each other and giving water to a sheet passing through the nip portion, a water-supply roller that pressure contacts the humidifying roller and supplies water to the humidifying roller, a water vessel that stores water to be supplied to the water-supply roller, and a pressure-contact releasing section that releases pressure-contact of the pair of humidifying rollers and releases pressure-contact between the humidifying roller and the water-supplying roller.

Abstract: A sheet processing apparatus including: a humidifier that humidifies a sheet; a curl correcting section that corrects a curl by applying mechanical bending force on a sheet; and a control section that causes humidification by the humidifier and curl correction by the curl correcting section to be possible for a prescribed sheet, and causes either one of humidification by the humidifier and curl correction by the curl correcting section to be possible for sheets other than the prescribed sheet.

Abstract: A sheet moisturizing device including paired moisturizing rollers, which are configured to be in contact with each other and to apply liquids onto a recording sheet while nipping to convey the recording sheet, wherein the paired moisturizing rollers are configured to include a mandrel, and a moisturizing layer which is formed on the mandrel and is formed of a porous body carrying independent cells which are not interconnected with each other, and a liquid supplying member which is configured to supply the liquid onto surfaces of the paired moisturizing rollers.

Abstract: A paper sheet humidifying device including a humidifying roller to convey a paper sheet and apply water to the paper sheet; a water supply roller to supply water to the humidifying roller; a water supply plate to contain the water for dipping the water supply roller, and to eject excessive water by overflowing; a water feeding section to feed the water to the water supply plate; a drain tank to receive the water ejected from the water supply plate, the drain tank comprising a drain outlet to eject the received water; a water level sensor to output a signal when a water level in the drain tank reaches a prescribed level; and a controller to execute a control to prevent overflowing of the water from the drain tank based on the signal from the water level sensor.

Abstract: A sheet humidifier which executes a humidifying process to a sheet, the sheet humidifier including: a pair of humidifying rollers each of which has a first surface layer formed of rubber containing plasticizer, the pair of humidifying rollers nipping and conveying the sheet; and two water supply rollers each of which has a second surface layer formed of rubber containing the same kind of plasticizer as the plasticizer of the first surface layer, the two water supply rollers contacting each of the pair of humidifying rollers and supplying water to the each of the pair of humidifying rollers, wherein a hardness of the first surface layer is higher than the second surface layer.

Abstract: A sheet moisturizing device, including: paired moisturizing rollers which form a nipping section to apply water onto a sheet when the sheet is conveyed through the nipping section; two water supplying rollers, each being in pressure contact to each of paired moisturizing rollers respectively; and two water supplying tanks, each arranged to face one of the water supplying rollers, wherein each of the two water supplying tanks is structured of a first tank which supplies water to the water supplying roller, and a second tank which is formed around the first tank and accommodates the water overflowed from the first tank.

Abstract: A sheet storing device that has a conveyance device that holds a folded sheet to convey and a sheet storing section on which a sheet falling after being released from holding is placed, and allows a position of holding lower end position of the aforesaid conveyance device to be variable, a post-processing apparatus equipped with the sheet storing device and an image forming system equipped with the aforesaid items.

Abstract: A sheet storing device having a conveyance device that converts the conveyance direction while holding the sheet and a storing section that has the first support member supporting the surface of the sheet substantially vertically, the second support member supporting the edge of the sheet and a pressing member pressing the sheet against the first support member, a post-processing apparatus equipped with the sheet storing device and an image forming system equipped with the aforesaid items.

Abstract: An image forming system, comprises an image forming section to form an image on a sheet; a fixing section to fix the image formed on the sheet; a sheet conveying passage to convey the fixed sheet; a humidifying roller arranged on the sheet passage and to humidify the sheet; a water supplying tank to feed water to the humidifying roller; an electric component; and a waterproofing member to protect the electric component from water.

Abstract: A decurl device includes: a curl detecting section having a plurality of toothed wheels each which detects a curling amount and a curling direction of a sheet having a curl; and a plurality of uncurling sections each arranged downstream of the curl detecting section in a conveyance direction of the sheet having the curl, which uncurls the sheet by bending and transforming the sheet in a direction reverse to a curling direction thereof. One of the uncurling sections, which reduces the curl, is selected on the basis of the curling amount and the curling direction that have been detected by the curl detecting section, thereby uncurling the sheet.

Abstract: A sheet processing apparatus including: a humidifier that humidifies a sheet; a curl correcting section that corrects a curl by applying mechanical bending force on a sheet; and a control section that causes humidification by the humidifier and curl correction by the curl correcting section to be possible for a prescribed sheet, and causes either one of humidification by the humidifier and curl correction by the curl correcting section to be possible for sheets other than the prescribed sheet.

Abstract: A sheet humidifying device includes a pair of humidifying rollers which form a nip portion by pressure contacting against each other and giving water to a sheet passing through the nip portion, a water-supply roller that pressure contacts the humidifying roller and supplies water to the humidifying roller, a water vessel that stores water to be supplied to the water-supply roller, and a pressure-contact releasing section that releases pressure-contact of the pair of humidifying rollers and releases pressure-contact between the humidifying roller and the water-supplying roller.

Abstract: A sheet humidifying device includes: a humidifier having a pair of humidifying rollers which form a nip by being in contact with each other and humidify a sheet that passes through the nip; and a water supply tray which stores water to be supplied to the humidifier, having a wall forming a chamber that stores the water, and a water outlet causing the water to overflow from the chamber, which is formed on the wall.

Abstract: A sheet moisturizing device having a moisturizing section that moisturizes a sheet and a guide which guides the sheet that has been moisturized by the moisturizing section, the guide includes a first guide member made of resin having a plurality of ribs, arranged immediately downstream of the moisturizing section in a sheet conveyance direction, which guides the sheet in a vertical direction.

Abstract: A sheet moisturizing apparatus, including a vertical conveyance route in which a sheet is guided upward or downward and paired moisturizing units which are mounted symmetrically to sandwich the vertical conveyance route.

Abstract: A sheet moistening device comprises a pair of moistening rollers which respectively have porous layers and form a nip to convey a sheet, and a dampening mechanism which supplies water to at least one of the pair of moistening rollers through a surface thereof. In the sheet moistening device, a roller surface hardness differs between the pair of moistening rollers. In addition, the sheet moistening device can further comprise a regulating device which regulates an amount of water to be supplied from the dampening mechanism to the moistening roller.