JP4927643B2 - Discharge stand, image forming apparatus, and sheet stacking method - Google Patents

Description

  The present invention relates to a paper discharge tray which is provided in a printing apparatus such as a stencil printing apparatus, an image forming apparatus such as a copying machine, a facsimile machine, or a printer, and on which a sheet such as a sheet on which image formation has been performed, and an image formation including the same The present invention relates to an apparatus and a sheet stacking method using them.

  Conventionally, as described in [Patent Document 1], [Patent Document 2], etc., when the leading edge of a sheet that has been image-formed and moved toward the paper discharge table collides with the paper discharge table. Various techniques have been proposed for preventing or mitigating noise generated in the environment.

[Patent Document 1] describes a technique for preventing or mitigating such noise by configuring the front end of the sheet to come into contact with the sponge.
[Patent Document 2] describes a technique for preventing or mitigating such noise by configuring the front end of a sheet to abut against an elastic plate.

Japanese Patent Laid-Open No. 11-217151 JP-A-8-20468

However, development of a new technology for preventing or mitigating such noise is awaited.
Note that the sponge described in [Patent Document 1] and the elastic plate described in [Patent Document 2] have a large effect of rebounding the sheet when the sheet comes into contact, and the alignment of the sheet on the sheet discharge table may be deteriorated. There is sex.
[Patent Document 1] also describes an example in which a thin film is pasted on the surface of the sponge in order to smooth the fall after the sheet abuts in view of the large friction on the surface of the sponge. When a film is pasted, there is a possibility that the noise when the sheet comes into contact will increase, and there is a trade-off relationship between noise prevention and ensuring a smooth drop of the sheet.

  The present invention provides an image forming apparatus provided in an image forming apparatus such as a stencil printing apparatus, a copying machine, a facsimile machine, or a printer that prevents or reduces noise caused by contact of a sheet on which an image is formed with a new configuration. It is an object of the present invention to provide a paper discharge table for stacking sheets such as paper sheets, an image forming apparatus including the same, and a sheet stacking method using the same.

In order to achieve the above object, the invention according to claim 1 is a discharge table on which sheets on which images have been formed is stacked, and has an airbag that contacts the leading edge of the sheet that has moved toward the discharge table. In the airbag, the gas for inflating the airbag is supplied by the gas supply unit provided on the discharge tray or the main body side of the image forming apparatus having the discharge tray .

  According to a second aspect of the present invention, in the paper discharge stand according to the first aspect, the surface of the airbag on the side where the leading edge of the sheet abuts has a non-planar shape.

  According to a third aspect of the present invention, in the paper discharge stand according to the second aspect, the surface of the airbag on the side where the leading edge of the sheet abuts has a convex shape at the center in the width direction of the sheet. It is characterized by.

  According to a fourth aspect of the present invention, in the paper discharge stand according to the second aspect, the surface of the airbag on the side where the leading edge of the sheet abuts has a convex shape at both ends in the width direction of the sheet. It is characterized by.

  According to a fifth aspect of the present invention, in the paper discharge platform according to any one of the first to fourth aspects, the airbag is divided into a plurality of parts in the width direction of the sheet.

  According to a sixth aspect of the present invention, in the paper discharge platform according to any one of the first to fifth aspects, the surface of the airbag on the side where the front end of the sheet abuts has an overhang shape. It is characterized by.

  A seventh aspect of the present invention is the paper discharge platform according to any one of the first to sixth aspects, wherein the surface of the airbag on the side where the front end of the sheet contacts is made of a material having smoothness. It is characterized by.

  According to an eighth aspect of the present invention, in the paper discharge platform according to any one of the first to seventh aspects, the surface of the airbag on the side where the leading edge of the sheet abuts is made of a material having air permeability. It is characterized by.

  According to a ninth aspect of the present invention, in the paper discharge stand according to the eighth aspect, the air permeability of the surface of the airbag on the side where the front end of the sheet abuts is non-uniform.

  According to a tenth aspect of the present invention, in the discharge table according to the ninth aspect, the air permeability of a portion of the airbag on the side where the leading end of the sheet abuts, in the vertical direction, the portion where the leading end of the sheet abuts, It is characterized by being larger than the air permeability of other parts.

  According to an eleventh aspect of the present invention, in the paper discharge stand according to the ninth or tenth aspect, the air permeability of the central portion in the width direction of the sheet of the surface of the airbag on the side where the leading end of the sheet abuts is It is characterized by being larger than the air permeability at both ends in the width direction.

  According to a twelfth aspect of the present invention, in the discharge table according to the ninth or tenth aspect, the air permeability of both ends in the sheet width direction of the surface of the airbag on the side where the leading edge of the sheet abuts is It is characterized by being larger than the air permeability of the central portion in the width direction.

  According to a thirteenth aspect of the present invention, in the paper discharge stand according to any one of the first to twelfth aspects, an antistatic process is performed on a surface of the airbag on a side where the leading end of the sheet contacts. Features.

  A fourteenth aspect of the present invention is the discharge table according to any one of the first to thirteenth aspects, wherein the surface of the airbag on the side where the front end of the sheet abuts is made of a conductive material. It is characterized by.

  According to a fifteenth aspect of the present invention, in the paper discharge stand according to any one of the first to fourteenth aspects, the gas discharge means for discharging the gas in the airbag is provided.

  According to a sixteenth aspect of the invention, there is provided the paper discharge table according to the fifteenth aspect, further comprising gas discharge amount condition control means for changing a gas discharge amount by the gas discharge means in accordance with an image forming condition. .

  According to a seventeenth aspect of the present invention, in the paper discharge stand according to the fifteenth or sixteenth aspect, a gas discharge for changing the amount of gas discharged by the gas discharge means when the sheet falls in contact with the airbag. It has quantity variation control means.

According to an eighteenth aspect of the present invention, in the paper discharge stand according to any one of the first to seventeenth aspects, the gas supply means is provided .

  According to a nineteenth aspect of the present invention, there is provided an image forming apparatus having the paper discharge table according to any one of the first to seventeenth aspects.

  According to a twentieth aspect of the present invention, there is provided an image forming apparatus having the discharge table according to the eighteenth aspect.

According to a twenty-first aspect of the present invention, in the image forming apparatus according to the nineteenth aspect, the gas supply means is provided on the image forming apparatus main body side, and the gas supply means is also provided at another part on the image forming apparatus main body side. It is used.

  According to a twenty-second aspect of the present invention, in the image forming apparatus according to the twentieth or twenty-first aspect, the gas supply unit includes a gas supply unit drive control unit that operates during the image forming operation.

  According to a twenty-third aspect of the present invention, in the image forming apparatus according to any one of the twenty-second to twenty-second aspects, the amount of gas supplied to the airbag by the gas supply unit is set according to image forming conditions. It has a gas supply amount condition control means for changing.

  According to a twenty-fourth aspect of the present invention, in the image forming apparatus according to the twenty-third aspect, there is provided a gas introduction amount adjusting unit that adjusts an amount of the gas supplied from the gas supply unit toward the airbag. And the gas supply amount control means controls the adjustment of the amount of gas introduced into the airbag by the gas introduction amount adjustment means.

  According to a twenty-fifth aspect of the present invention, in the image forming apparatus according to any one of the twenty-fourth to twenty-fourth aspects, the amount of gas supplied to the airbag by the gas supply means is determined by the sheet against the airbag. It is characterized by having a gas supply amount fluctuation control means for changing when falling in contact.

  According to a twenty-sixth aspect of the present invention, there is provided the image forming apparatus according to the twenty-fifth aspect, further comprising: a gas introduction amount adjusting unit that adjusts an amount of the gas supplied by the gas supply unit toward the airbag. And adjusting the amount of gas introduced into the airbag by the gas introduction amount adjusting means by the gas supply amount fluctuation controlling means.

  A twenty-seventh aspect of the present invention is the image forming apparatus according to the twenty-fourth or twenty-sixth aspect, wherein the airbag is divided into a plurality in the sheet width direction, and the gas introduction amount adjusting means is A plurality of airbags corresponding to each of the divided airbags are provided, and the amount of gas introduced into the airbag by each gas introduction amount adjusting means is independently adjusted.

  A twenty-eighth aspect of the invention is the image forming apparatus according to any one of the twentieth to twenty-seventh aspects, wherein the air bag is divided into a plurality of pieces in the sheet width direction. A plurality of supply means are provided corresponding to each of the divided airbags, and the amount of gas supplied by each gas supply means is independently adjusted.

  A twenty-ninth aspect of the invention is the image forming apparatus according to any one of the nineteenth to twenty-eighth aspects, wherein the airbag is divided into a plurality in the width direction of the sheet, In an image forming apparatus having a gas discharge means for discharging gas, the gas discharge means includes a plurality of the gas discharge means corresponding to each of the divided airbags, and the gas discharge amount by each gas discharge means is independently adjusted. It is characterized by being.

  According to a thirty-third aspect of the invention, in the image forming apparatus according to any one of the twentieth to thirty-ninth aspects, the gas supply means causes the sound generated by driving to have a main spectrum in a low frequency range having low hearing sensitivity. It is characterized by having.

  According to a thirty-first aspect of the present invention, there is provided the paper discharge table according to any one of the first to eighteenth aspects or the image forming apparatus according to any one of the nineteenth to nineteenth aspects. There is a sheet stacking method for stacking sheets.

The present invention provides a paper discharge tray for stacking the sheet on which an image has been formed, the leading end of the sheet which has moved toward the discharge tray is closed the air bag in contact, the air bag, the same airbag The gas to be inflated is supplied by the gas supply unit provided on the discharge tray or the main body side of the image forming apparatus having the discharge tray, so that noise caused by contact of the sheet on which image formation has been performed can be prevented. The sheet can be quieted by relaxing, and the sheet alignment can be improved by preventing or alleviating the rebound of the sheet in contact with the airbag, and a discharge tray with a high usability can be provided.

  Assuming that the surface of the airbag on the side where the leading edge of the sheet abuts has a non-planar shape, the abutting of the sheet on which the image has been formed starts from a part of the airbag and gradually abuts. By increasing the area, the contact can be performed gradually, and therefore, the noise caused by the contact can be reduced or silenced, and the sheet that is in contact with the airbag can be prevented from rebounding or reduced. The sheet alignment can be improved, and a discharge tray with a high usability can be provided.

  Assuming that the surface of the airbag on the side where the leading edge of the sheet abuts has a convex shape at the center in the width direction of the sheet, the abutting of the sheet on which image formation has been performed Starting from the central portion in the width direction, the contact area gradually expands so that contact can be gradually performed. Preventing or mitigating bounce of the contacted sheet can improve the alignment of the sheet, and the feeling of use is high. Especially, if the sheet is aligned at the center, these effects are good for various size sheets. It is possible to provide an output tray that can be demonstrated.

  If the surface of the airbag on the side where the leading edge of the sheet abuts has both ends in the width direction of the sheet convex, the abutting of the sheet on which image formation has been performed Starting from both end portions in the width direction, the contact area gradually expands so that contact can be gradually performed. Therefore, noise can be reduced by preventing or mitigating the sound caused by such contact, and can be applied to the airbag. By preventing or alleviating bounce of the contacted sheet and preventing or suppressing the inclination of the sheet due to contact, the alignment of the sheets can be improved, and a discharge stand having a high feeling of use can be provided.

  If the airbag is divided into a plurality of parts in the width direction of the sheet, the noise can be reduced by preventing or mitigating the noise caused by the contact of the sheet on which the image has been formed, and the airbag is in contact with the airbag. The seat alignment can be improved by preventing or alleviating the bounce of the seat, and the feeling of use is high, and the strength and stability are improved by dividing the airbag, and the inner volume of the airbag is reduced. Thus, it is possible to provide a paper discharge table that can save energy for inflating the airbag.

  If the surface of the airbag on the side where the leading edge of the sheet abuts is an overhang, it can be silenced by preventing or mitigating the noise caused by the abutting of the sheet on which the image has been formed. In addition, the sheet falling and aligning can be improved by preventing or mitigating the rebounding of the sheet in contact with the airbag and the contact of the sheet after contacting with the airbag. Can be provided.

  If the surface of the airbag on the side where the leading edge of the sheet abuts is made of a material having smoothness, the sound caused by the abutting of the sheet on which the image has been formed is prevented or alleviated. It is possible to reduce the noise, and the fall and alignment of the sheet can be improved by preventing or mitigating the bounce of the sheet in contact with the airbag and the contact of the sheet after the contact with the airbag. A paper discharge stand can be provided.

  If the surface of the airbag on the side where the leading edge of the sheet abuts is made of a material having air permeability, the sound caused by the abutting of the sheet on which the image has been formed is prevented or alleviated. It is possible to reduce noise and prevent or alleviate the bounce of the seat in contact with the airbag. By preventing or alleviating the catching, the fall and alignment of the sheet can be improved, and a sheet discharge stand with a high usability can be provided.

  If the air permeability of the surface of the airbag where the leading edge of the sheet comes into contact is non-uniform, it can be silenced by preventing or mitigating the sound caused by the contact of the sheet on which image formation has been performed, It also prevents or mitigates the bounce of the seat that comes into contact with the airbag, and air in the airbag when the seat comes into contact with the airbag due to an air bag whose air permeability is partially adjusted, or when the seat falls afterwards. By preventing or alleviating the sheet from being caught on the airbag by being pulled out, the fall and alignment of the sheet can be improved, and a discharge tray with a high usability can be provided.

  If the air permeability of the portion of the airbag on the side where the front end of the sheet abuts is higher than the air permeability of the other portion in the vertical direction, the image formation is performed. The noise can be reduced by preventing or mitigating the noise caused by the contact of the seat, and by preventing or mitigating the bounce of the seat in contact with the airbag, or by increasing the air permeability at the portion where the seat abuts. When the seat comes into contact with the airbag, the air in the airbag is easy to escape, and when the seat falls, the seat falls by preventing or mitigating the seat from being caught by the airbag. In addition, it is possible to improve the alignment and provide a sheet discharge table with a high usability.

  If the air permeability of the central portion in the sheet width direction of the surface of the airbag on the side where the front end of the sheet abuts is greater than the air permeability of both ends in the sheet width direction, image formation is performed. The seat can be silenced by preventing or mitigating noise caused by the contact of the seat, and preventing or mitigating the rebound of the seat in contact with the airbag, or by increasing the air permeability at the central portion of the seat. The air in the air bag easily escapes when it comes into contact with the air bag, and the air drops in the air bag at the time of subsequent fall prevent or relax the seat from falling or aligning the seat. It is easy to use, especially if the sheet is centered, and these effects are good for various size sheets. It is possible to provide a discharge tray to be exerted.

  If the air permeability of both ends in the sheet width direction of the surface of the airbag on the side where the front end of the sheet abuts is greater than the air permeability of the center in the sheet width direction, image formation is performed. The noise can be reduced by preventing or mitigating the noise caused by the contact of the seat, and the seat can be prevented by preventing or mitigating the rebound of the seat in contact with the airbag or by increasing the air permeability at both ends. Air in the air bag easily escapes when it comes into contact with the air bag, and prevents or eases the seat from being caught by the air bag due to the air in the air bag coming off when it falls later. By preventing or suppressing the tilt, it is possible to improve the fall and alignment of the sheet, and it is possible to provide a discharge stand with a high feeling of use. .

  Assuming that antistatic processing is performed on the surface of the airbag on which the front end of the sheet comes into contact, noise can be reduced by preventing or mitigating noise caused by contact of the sheet on which image formation has been performed, Further, the sheet alignment can be improved by preventing or alleviating the rebound of the sheet in contact with the airbag and preventing or alleviating the charging of the sheet, thereby providing a sheet discharge stand having a high usability.

  If the surface of the airbag on the side where the leading edge of the sheet abuts is made of a conductive material, the noise caused by the abutting of the sheet on which the image has been formed is prevented or alleviated. The noise can be reduced, and the sheet alignment can be improved over time by preventing or mitigating rebounding of the sheet in contact with the airbag and preventing or mitigating charging of the sheet over time. It is possible to provide a paper discharge stand with a high usability.

  If there is a gas discharge means for discharging the gas in the airbag, the sound generated by the contact of the sheet on which the image has been formed is adjusted by adjusting the inflation state of the airbag by discharging the gas in the airbag. It is possible to reduce the noise by preventing or alleviating the sheet, and to improve the alignment of the sheet by preventing or alleviating the bounce of the sheet in contact with the airbag. it can.

  If it has gas discharge amount condition control means for changing the gas discharge amount by the gas discharge means according to the image forming conditions, the gas in the airbag is used for image formation such as sheet thickness and size. By discharging according to the conditions, the airbag is adjusted to an inflated state suitable for the image forming conditions, and the noise caused by the contact of the sheet on which the image has been formed can be reduced or silenced. By preventing or alleviating the rebound of the sheet in contact with the airbag, the alignment of the sheets can be improved, and a sheet discharge stand with a high usability can be provided.

  If it has gas discharge amount variation control means for changing the amount of gas discharged by the gas discharge means when the sheet falls in contact with the airbag, the amount of gas discharged in the airbag is reduced. The air bag is inflated to change the state of the air bag, and the noise caused by the contact of the sheet on which the image has been formed can be reduced or silenced, and the sheet in contact with the airbag can be prevented from rebounding or mitigating. The seat alignment can be improved by changing the pressure of the gas in the airbag and changing the surface position of the airbag to prevent or restrain the seat from being caught by the airbag, and the feeling of use is high. A paper discharge stand can be provided.

If the gas supply means is provided, noise can be reduced by preventing or mitigating noise caused by contact of the sheet on which image formation has been performed, and prevention or mitigation of rebounding of the sheet in contact with the airbag. The sheet alignment can be improved, and the feeling of use is high, and the provision of gas supply means eliminates or eliminates the need to introduce gas into the airbag, providing a compact and lightweight paper discharge stand. can do.

  According to the present invention, there is provided an image forming apparatus having the sheet discharge table according to any one of claims 1 to 17, and therefore, there is provided a sheet discharge table having the above-described effects, and a sheet on which image formation has been performed. An image forming apparatus having a high usability can be achieved by preventing or alleviating noise caused by contact, and by reducing or preventing bounce of the sheet contacting the airbag to improve sheet alignment. Can be provided.

Since the present invention is an image forming apparatus having a paper discharge stand according to claim 18, it has a paper discharge stand that exhibits the above-mentioned effect, and prevents or alleviates the sound caused by contact of the sheet on which image formation has been performed. it can noise reduction by, also the sheet aligning of can be improved by preventing or mitigating the recoil abutting sheets airbag, high feeling, also, the air due to the provision of the gas supply means A configuration for introducing gas into the bag is unnecessary or small, and a small and lightweight image forming apparatus can be provided.

If the gas supply means is provided on the main body side of the image forming apparatus, and the gas supply means is also used for other parts on the main body side of the image forming apparatus, it is based on the contact of the sheet on which the image is formed. Noise can be reduced by preventing or mitigating noise, and seat alignment can be improved by preventing or mitigating bounce of the seat in contact with the airbag. Therefore, it is not necessary to newly dispose the gas supply means to be provided, and an image forming apparatus capable of suppressing costs can be provided.

  If the gas supply means has a gas supply means drive control means that operates during an image forming operation, noise can be reduced by preventing or mitigating noise caused by contact of the sheet on which image formation has been performed, and air By preventing or mitigating the bounce of the sheet that contacts the bag, the alignment of the sheet can be improved, the feeling of use is high, and the gas supply means is driven only when necessary to inflate the airbag. An image forming apparatus capable of saving necessary energy can be provided.

  If the gas supply means has gas supply amount condition control means for changing the amount of gas supplied to the airbag according to image forming conditions, the pressure of the gas in the airbag is adjusted to the thickness of the sheet. The air bag is adjusted according to the image forming conditions by changing the size and size according to the image forming conditions to prevent noise caused by contact of the sheet on which the image is formed. By mitigating, the noise can be reduced, and by preventing or alleviating the rebound of the sheet in contact with the airbag, the alignment of the sheets can be improved, and an image forming apparatus with a high usability can be provided.

  The gas supply means has gas introduction amount adjustment means for adjusting the amount of gas supplied toward the airbag, and the gas supply amount control means uses the gas introduction amount adjustment means. If the adjustment of the amount of gas introduced into the airbag is controlled, the gas pressure in the airbag is controlled by the gas introduction amount adjusting means to the image forming conditions such as the thickness and size of the sheet. The air bag can be made quieter by adjusting the inflated state of the air bag to a state suitable for the image forming condition by changing it accordingly, and preventing or mitigating the sound caused by the contact of the sheet on which the image has been formed. By preventing or alleviating the rebound of the sheet in contact with the sheet, the alignment of the sheets can be improved, and an image forming apparatus with a high usability can be provided.

  If the gas supply means has gas supply amount fluctuation control means for changing the amount of gas supplied to the airbag when the seat comes into contact with the airbag and falls, Adjusting the inflation state of the airbag by changing the amount of gas supplied and preventing or mitigating noise caused by the contact of the sheet on which the image has been formed. The sheet alignment can be improved by preventing or mitigating the rebound of the sheet and by changing the pressure of the gas in the airbag to displace the surface position of the airbag to prevent or suppress the sheet from being caught on the airbag. And an image forming apparatus having a high usability can be provided.

  A gas introduction amount adjusting means for adjusting an amount of the gas supplied by the gas supply means toward the airbag to be introduced into the airbag; and the gas introduction amount adjusting means by the gas supply amount variation control means. If the adjustment of the amount of gas introduced into the airbag is controlled by adjusting the amount of gas supplied to the airbag by the gas introduction amount adjusting means, the inflation state of the airbag is adjusted, Noise can be reduced by preventing or alleviating the noise caused by the contact of the sheet on which the image has been formed, preventing or mitigating rebounding of the sheet in contact with the airbag, and changing the pressure of the gas in the airbag. Alignment of the seat can be improved by displacing the surface position of the airbag to prevent or suppress the seat from being caught on the airbag. It can be the sense used to provide high image forming apparatus.

  In the image forming apparatus in which the airbag is divided into a plurality of sheets in the width direction of the sheet, the gas introduction amount adjusting means has a plurality corresponding to each of the divided airbags. If the amount of gas introduced into the airbag is adjusted independently, the amount of gas supplied to each part of the divided airbag is adjusted by the gas introduction amount adjusting means. By adjusting according to the size, etc., the inflated state of each part of the airbag can be adjusted, and the noise caused by the contact of the sheet on which the image has been formed can be reduced or silenced. By preventing or alleviating the rebound of the contacted sheet, the alignment of the sheets can be improved, and an image forming apparatus with a high usability can be provided.

  In the image forming apparatus in which the airbag is divided into a plurality of sheets in the width direction of the sheet, a plurality of the gas supply units are provided corresponding to each of the divided airbags, and gas is supplied by each of the gas supply units. If the amount is adjusted independently, the amount of gas supplied to each part of the divided airbag is adjusted by the gas supply means according to the thickness, size, etc. of the sheet. By adjusting the inflated state of each part of the bag to prevent or mitigate the noise caused by the contact of the sheet on which the image has been formed, it is possible to reduce the noise, and to prevent or mitigate the bounce of the sheet in contact with the airbag Therefore, the sheet alignment can be improved, and an image forming apparatus with a high usability can be provided.

  In the image forming apparatus, wherein the airbag is divided into a plurality of parts in the width direction of the sheet, and has a gas discharge unit that discharges the gas in the airbag, the gas discharge unit is divided into each of the divided airbags. Correspondingly, if the amount of gas discharged by each gas discharging means is adjusted independently, the amount of gas supplied to each part of the divided airbag is determined by the gas discharging means, By adjusting according to the thickness, size, etc. of the sheet, the inflated state of each part of the airbag can be adjusted, and noise can be reduced by preventing or mitigating noise caused by contact of the sheet on which image formation has been performed, Further, by preventing or alleviating the rebound of the sheet in contact with the airbag, the alignment of the sheets can be improved, and an image forming apparatus having a high usability is provided. Can.

  If the gas generated by the driving has a main spectrum in a low sound range with low hearing sensitivity, it is generated by the contact of the sheet on which the image is formed and the driving of the gas supplying unit. To provide an image forming apparatus that can be silenced by preventing or mitigating noise, and can improve sheet alignment by preventing or mitigating bounce of a sheet in contact with an airbag, and has a high usability. Can do.

  The present invention uses the paper discharge table according to any one of claims 1 to 18 or the image forming apparatus according to any one of claims 19 to 29 to stack sheets on the paper discharge table. Since the sheet stacking method is used, it is possible to reduce noise by preventing or alleviating the noise caused by the contact of the sheet on which the image has been formed with the paper discharge tray or the image forming apparatus that achieves each of the effects described above. It is possible to provide a sheet stacking method capable of improving the alignment of sheets by preventing or alleviating bounce of the contacting sheets.

  FIG. 1 shows an outline of a heat sensitive digital plate-making integrated stencil printing apparatus which is a printing apparatus as an image forming apparatus to which the present invention is applied. The stencil printing apparatus 100 includes an image scanner 61 serving as a document reading unit serving as a document reading unit for reading a document image on an upper part of an apparatus body 67 serving as an image forming apparatus body. The image scanner 61 includes a carriage 60 having a lamp 63 for illuminating a document set on a contact glass 62, a plurality of mirrors 64, an imaging lens 65, a one-dimensional array CCD 66, and the like. ing.

  The stencil printing apparatus 100 has a master roll 70a in the form of a roll formed at the lower part of the image scanner 61, a printing unit 69 centered on a rotatable plate cylinder 68 and an unused master 70 made of heat-sensitive stencil paper. A plate making apparatus 71 is provided as a plate making means as a plate making unit which is built in a replaceable manner and punches the master 70 drawn from the master roll 70a and supplies the master 70 which has been made to the plate cylinder 68.

  The stencil printing apparatus 100 also has a press roller 20 as a pressing body for pressing a printing paper P as a sheet to be fed toward the outer periphery of the printing drum 68 toward the printing drum 68, and the printing paper from the printing drum 68. A peeling claw 75 that can freely advance and retreat P and a plate discharging device 76 that is a plate discharging means for peeling the used master 70 wound around the plate cylinder 68 before the printing process are provided.

  The stencil printing apparatus 100 also conveys and discharges the printing paper P peeled off from the plate cylinder 68 by the peeling claw 75 and the paper feeding device 52 that feeds the printing paper P toward the printing unit 69. The paper discharge device 23 is stacked, the ink supply device 10 is mainly located inside the plate cylinder 68, and the main motor 11 is a drive motor as plate cylinder driving means.

  The stencil printing apparatus 100 also includes a pressing body displacing means 22 that displaces the press roller 20 toward the plate cylinder 68 and holds the press roller 20 at a position separated from the plate cylinder 68, and an operator such as a user, that is, an operator, performs stencil printing. An operation panel 91 shown in FIG. 2 for operating the apparatus 100 and a control unit 90 as control means shown in FIG. 2 for controlling the overall operation and the like of the stencil printing apparatus 100 are provided.

  The plate cylinder 68 is a porous support cylinder (not shown) provided with a clamp device 73 for gripping the end of the master 70 that has been made, and an opening (not shown) and a non-opening (not shown). A multi-layer mesh screen (not shown) that is a resin or metal mesh covering the outer periphery of the porous support cylinder, and drum flanges (not shown) fixed to both ends of the porous support cylinder. It is connected to the main motor 11 through a gear train that does not.

  The opening of the porous support cylindrical body is a portion in which a large number of small holes for allowing the ink supplied by the ink supply device 10 to pass therethrough, and the transmitted ink is configured to ooze out from the mesh screen. Yes.

  Each drum flange is rotatably supported by a drum shaft 25 shown in FIG. 1 as an ink supply pipe which is an ink supply shaft. The drum shaft 25 is supported by a main body side plate (not shown) of the apparatus main body 67. Therefore, the plate cylinder 68 is rotatably supported by the drum shaft 25 by the drum flange.

  As shown in FIG. 1, the plate cylinder 68 is integrated with the gear 12 having the drum shaft 25 as the rotation center. The main motor 11 is a stepping motor, and is fixed to the main body side plate and has a gear 13 that meshes with the gear 12. Therefore, the plate cylinder 68 is rotationally driven by the main motor 11. The plate cylinder 68 is driven to rotate in the clockwise direction in FIG.

  The clamp device 73 is disposed in a non-opening portion other than the mesh screen of the porous support cylindrical body along one of the bus bars of the plate cylinder 68, and the stage 14 made of a magnetic material and the stage 14 It has a clamper 42 that opens and closes and that clamps the tip of the master 70 with the stage 14 to which a magnet or the like is attached.

  The clamp device 73 is also arranged in parallel with the stage 14 in the direction perpendicular to the paper surface in FIG. 1, and forms a center of rotation of the clamper 42. In the position, an opening / closing device (not shown) that opens and closes the stage 14 is provided.

  The ink supply device 10 is disposed so as to face the inner peripheral surface of the plate cylinder 68 and supplies the ink 15 to the plate cylinder 68. The ink supply device 10 faces the ink roller 16 and has a slight gap in the ink roller 16. A doctor roller 18 that forms a wedge-shaped space with the ink roller 16 and forms an ink reservoir 17 in the wedge-shaped space; a drum shaft 25 that drops and supplies the ink 15 to the ink reservoir 17; And a pair of ink roller side plates (not shown) that rotatably support the ink roller 16 and the doctor roller 18 therebetween.

  Although not shown, the ink supply device 10 supplies an ink pack connected to one end of the drum shaft 25 and positioned outside the plate cylinder 68 and ink in the ink pack toward the drum shaft 25. An ink pump located outside the plate cylinder 68, an ink sensor for detecting the amount of ink in the ink reservoir 17, and the driving force of the main motor 11 are transmitted to the ink roller 16 and the doctor roller 18, and the ink roller 16 and the doctor roller 18 are transferred to the plate. A driving force transmission mechanism constituted by gears, belts, and the like that is driven to rotate in the same direction as the plate cylinder 68 in synchronization with the cylinder 68.

  The drum shaft 25 is formed with a plurality of holes 25a as supply holes which are ink dropping holes in the axial direction, and has a function of an ink supply pipe. The drum shaft 25 has an ink roller side plate fixed to both ends thereof.

  The ink roller 16 has an ink roller shaft 21 that forms the center of rotation, and the ink roller shaft 21 is rotatably supported at both ends by an ink roller side plate. The doctor roller 18 is also rotatably supported on the ink roller side plate in the same manner as the ink roller 16.

  Accordingly, the ink roller 16 and the doctor roller 18 rotate to knead and extend the ink 15 in the ink reservoir 17, and the ink 15 in the ink reservoir 17 extends from between the ink roller 16 and the doctor roller 18 to the outer surface of the ink roller 16. After that, the ink is supplied to the inner peripheral surface of the plate cylinder 68.

The ink 15 supplied to the inner peripheral surface of the plate cylinder 68 oozes out to the outer peripheral surface of the plate cylinder 68 through the porous support cylindrical body and a plurality of layers of mesh screens.
When it is detected that the ink 15 has been consumed and the amount of ink in the ink reservoir 17 has been reduced by the ink sensor, the ink in the ink pack is sucked by the ink pump, and from the plurality of holes formed in the drum shaft 25, the ink reservoir 17 is supplied.

  The press roller 20 is located below the plate cylinder 68. The press roller 20 includes a cored bar and nitrile rubber or chloroprene rubber as an elastic body that is formed in a cylindrical shape and is mounted around the cored bar.

  The press roller 20 is displaced toward the plate cylinder 68 at a predetermined timing by the pressing body displacing means 22, and presses the printing paper P toward the plate cylinder 68 at the nip portion N that is a portion facing the plate cylinder 68. In this way, the ink is pressed against the master 70 wound around the plate cylinder 68 and the ink oozing from the master 70 is adhered to the printing paper P to perform printing.

  The master 70 attached to the plate making apparatus 71 is made of a thermoplastic resin film having a thickness of approximately 1 to 3 μm and a paper sheet, synthetic fiber, or a mixture of Japanese paper fiber and synthetic fiber, which is a support sheet of a porous support. Laminated laminate structure.

  The plate making apparatus 71 includes a master flange 88 as a holder means for holding the master roll 70a rotatably and guiding the conveyance of the master 70 fed out from the master roll 70a, and a roller pair 89 for pulling out the master 70 from the master roll 70a. The platen roller 77 further conveys the master 70 drawn out by the roller pair 89, and a thermal head 78 that is a perforating member as a plate-making head disposed opposite to the platen roller 77.

  The plate making apparatus 71 also includes a cutter 80 that cuts the master 70 that has been made into a predetermined length, a roller pair 79 that transports the master 70 that has been punched by the thermal head 78 toward the plate cylinder 68, and A guide plate 74 that guides the master 70 that has been subjected to plate making toward the plate cylinder 68 is provided.

  Although not shown, the plate making apparatus 71 also includes a master conveyance drive motor that is a stepping motor that rotationally drives the roller pair 89 and 79, and a pair of plate making unit side plates that rotatably support the platen roller 77 therebetween. Yes.

  The master roll 70a is obtained by winding the master 70 around a roll core 37 that is a winding core as a winding member, and the master flange 88 holds the roll core 37 detachably and rotatably. Thus, the master roll 70a is held detachably and rotatably about the roll core 37.

  The thermal head 78 has a heat generating portion constituted by an infinite number of heat generating elements along a direction perpendicular to the paper surface of FIG. The thermoplastic resin film of the master 70 is located on the thermal head 78 side, and the thermal head 78 melts the thermoplastic resin film portion of the master 70 conveyed by the roller pairs 89 and 79 and the platen roller 77 by the heat generating portion. It comes to pierce. Each heating element constituting the heating unit generates heat by energization, and energization control to each heating element is performed by the control unit 90.

  The roller pairs 89 and 79 are rotatably supported between the plate making unit side plates while being in pressure contact with each other. The master conveyance drive motor is configured to rotationally drive the roller pairs 89 and 79 by energization, and the energization control to the master conveyance drive motor is performed by the control unit 90.

  The conveyance speed of the master 70 by the roller pair 79 is set to be higher than the conveyance speed of the master 70 by the platen roller 77, and a predetermined tension is applied to the master 70 while causing a slip with the master 70. ing. The cutter 80 is provided with guillotine type upper and lower blades in this embodiment, but may be a rotary blade moving type rotary type or the like. The guide plate 74 is fixed between the plate making unit side plates.

  In the thermal head 78, the heating element generates heat based on image data based on the original read by the image scanner 61 and other image data input from an external device such as a personal computer, and the master 70 is punched.

  The plate removal device 76 peels off the master 70 from the plate cylinder 68 and conveys it, and the plate removal box 54 that stores the used master 70 that has been peeled off and conveyed from the plate cylinder 68 by the master peeling device 53. And have.

  The sheet feeding device 52 is synchronized with the rotational movement of the sheet feed table 81 on which the printing paper P provided so as to be movable up and down, the sheet feed roller 82 disposed above the sheet feed table 81, and the plate cylinder 68 are rotated. A registration roller pair 83 that feeds the printing paper P fed by the paper feed roller 82 to the printing unit 69, and guides the printing paper P fed by the paper feed roller 82 to the registration roller pair 83. Guide plates 40 and 41 for guiding the printing paper P fed from the registration roller pair 83 toward the printing unit 69 to the nip portion N, and a paper detection device (not shown).

  The paper feed roller 82 feeds the uppermost print paper P among the print papers P stacked on the paper feed table 81, and is rotated at a fixed position. The paper feed table 81 is controlled to rise and fall according to the number and thickness of the printing paper P so that the uppermost printing paper P contacts the paper feeding roller 82. The registration roller pair 83 feeds the printing paper P to the nip portion N at a predetermined timing when the image area of the master 70 enters the nip portion N.

  In the paper discharge device 23, a paper conveyance device 84 that conveys the printing paper P peeled off from the plate cylinder 68 by the peeling claw 75, and a printed printing paper P that has been conveyed by the paper conveyance device 84, that is, image formation is performed. A paper discharge tray 85 serving as a paper discharge tray on which the print paper P is stacked.

  The paper conveying device 84 includes a driving roller 55 and a driven roller 56, a conveying belt 58 as a paper discharge belt wound around the driving roller 55 and the driven roller 56, and an adsorption for adsorbing the printing paper P on the conveying belt 58. And a fan 57.

  The sheet conveying device 84 also rotates the driving roller 55 to drive the conveying belt 58, and the sheet conveying driving motor 24 shown in FIG. The flying printing paper P has a waist member (not shown) that is seated by making it U-shaped (see FIG. 4) in a cross section by a plane perpendicular to the paper discharge direction A which is the flight direction shown in FIG. is doing.

  As shown in FIG. 1 or FIG. 3, the paper discharge tray 85 discharges the printing paper P that has been moved in the direction A toward the paper discharge tray 85 by the paper transport device 84 after being printed by the printing unit 69. The printing paper P is stacked and held.

  The paper discharge tray 85 includes a paper discharge tray 31 having a substantially horizontal upper surface on which the print paper P is stacked, an end fence 32 suspended from the downstream end of the paper discharge tray 31 in the A direction, and the print paper P. In the width direction perpendicular to the paper surface of FIG. 1, and in the direction indicated by arrow B in FIG. 3, the distance between the two sides of the paper discharge tray 31 is adjusted and the both side edges of the printing paper P are adjusted. And a pair of side fences 33 that regulate the above.

  The paper discharge tray 85 is also disposed on the upstream surface of the end fence 32 in the A direction, and the airbag 34 is in contact with the leading edge of the printing paper P flying in the A direction. The air supply fan 35 is disposed at a position downstream of the end fence 32, and serves as a gas supply means for supplying air, which is a gas for inflating the air bag 34, into the air bag 34, and air in the air bag 34. It has an exhaust valve 36 that is an electromagnetic valve as a gas discharge means for discharging the air bag 34 to the outside.

  A hole (not shown) is formed in the end fence 32, and the air supply fan 35 supplies air into the airbag 34 through the hole when energized. A hole (not shown) is formed in the paper discharge tray 31, and the exhaust valve 36 exhausts air to the outside of the airbag 34 through the hole when energized. The energization of the air supply fan 35 and the energization of the exhaust valve 36 are performed independently by the control unit 90.

  The air supply fan 35 is in a state where the air bag 34 is inflated when at least the printing paper P is transported by the paper transporting device 84 and transported to the paper discharge tray 85 and the leading end abuts against and collides with the air bag 34. Driven by.

The airbag 34 has a surface on the upstream side in the A direction, that is, a surface on which the printing paper P abuts as a buffering surface 38, and noise that may be generated when the printing paper P collides in an inflated state. Is to prevent, mitigate, or suppress. Here, the airbag 34 functions as a buffer member that prevents, reduces, or suppresses such noise.
Other detailed configurations, operations, operations, and the like of the paper discharge tray 85 will be described later.

  The operation panel 91 includes an operation key 87 for performing operations necessary for printing by the stencil printing apparatus 100, and a display unit 96 for performing display for notifying the operator of the state of the stencil printing apparatus 100. .

  The display unit 96 is a touch-panel type liquid crystal display panel, which displays information for notifying the operator of the state of the stencil printing apparatus 100 and the like. A predetermined operation on the printing apparatus 100 can also be performed.

  The operation keys 87 are a plate making start key 92 for inputting a plate making start command signal for starting plate making in the plate making apparatus 71, a numeric key 93 for inputting numbers such as the number of prints, and printing as a printing speed setting means for setting a printing speed. And a speed setting key 94.

  The control unit 90 includes a CPU 97, a ROM 98 as a first storage unit that stores an operation program of the stencil printing apparatus 100 and various data necessary for the operation of the operation program, and a stencil such as image data read by the image scanner 61. The configuration includes a RAM 99 as second storage means for storing data necessary for the operation of the printing apparatus 100.

  In the ROM 98, the exhaust valve 36 is operated, such as a gas supply means operation program for operating the air supply fan 35, such as the timing of energizing the air supply fan 35, the strength of energization, and the timing of energizing the exhaust valve 36. For example, a gas discharge means operation program for operating the air supply adjustment valve 39, such as a gas discharge means operation program, and a timing of energization of the air supply adjustment valve 39 to be described later, are stored.

  The gas supply means operation program, the gas discharge means operation program, and the gas introduction amount adjustment means operation program constitute an airbag anti-shrink operation program for inflating and contracting the airbag 34. Here, the ROM 98 functions as an airbag inflation / deflation operation program storage unit, and the control unit 90 functions as an airbag inflation / deflation control unit.

  Note that when the control unit 90 controls the paper discharge device 23, it is equivalent to being provided as a part of the paper discharge device 23 in order to perform the function of the paper discharge device 23. Shall be composed.

  A series of printing operations of the entire stencil printing apparatus 100 will be described. After this description, the operation of the paper discharge tray 85 will be described more specifically.

  When an operator sets a document on the image scanner 61 and depresses a plate-making start key 92 to generate a plate-making start command signal, the image scanner 61 starts reading the document and the main motor 11 The plate cylinder 68 is rotationally driven in the clockwise direction in FIG. 1, and in this process, a used master (not shown) is peeled off from the plate cylinder 68 by the plate discharging device 76 and discarded.

  The plate cylinder 68 is further rotated, and then stops when the clamping device 73 occupies the substantially right end position in FIG. When the plate cylinder 68 stops, the clamper 42 is released by the opening / closing device, and the plate feed standby state is entered.

  On the other hand, plate making to the master 70 is performed by the plate making apparatus 71 according to the image information read by the image scanner 61. The master 70 may be made based on image data input from an external device.

  When the platen roller 77 and the roller pairs 89 and 79 are rotated and the master 70 is conveyed by one line in the sub-scanning direction, the master 70 is made by specifying the thermal head 78 in accordance with the image information constituted by the image data. A voltage is applied in a pulse form to the resistance heating element, and the thermoplastic resin film constituting the master 70 is heated and perforated, and plate making is performed by dot formation in the main scanning direction.

  The master 70 that has been made in this manner is sent out toward the plate cylinder 68 by the roller pair 79 and is guided by the guide plate 74, and the tip of the master 70 enters between the stage 14 and the clamper 42. When it is determined by the number of pulses of the master conveyance drive motor that the tip of the master 70 has reached the stage 14, the clamper 42 is closed by the opening / closing device, and the tip of the master 70 is clamped by the clamp device 73.

  When the clamper 42 is closed, the rotational drive of the plate cylinder 68 is resumed. The rotational speed of the plate cylinder 68 is the same as the conveying speed of the master 70. Due to the rotation of the plate cylinder 68, the master 70 which has been subjected to plate making is wound around the outer peripheral surface of the plate cylinder 68 so as to cover the opening of the porous support cylindrical body provided in the plate cylinder 68.

  When it is determined that the plate making is completed based on the number of pulses of the master conveying motor, the cutter 80 is operated to cut the master 70, the rotational driving of the platen roller 78 and the roller pair 89, 79 is stopped, and the cut master 70 is cut. Is pulled out to the plate cylinder 68 as the plate cylinder 68 rotates, and the winding around the plate cylinder 68 is completed.

  Thereafter, the printing process is executed. The uppermost printing paper P of the paper feed table 81 is fed by the paper feeding roller 82, and the leading edge of the printing paper P comes into contact with the nip portion of the resist roller pair 83 in a stopped state to align the leading edge.

  The registration roller pair 83 is driven in synchronization with the rotation of the plate cylinder 68, and it is detected by the paper detection device that the leading edge of the printing paper P has reached the vicinity of the nip N between the plate cylinder 68 and the press roller 20. The press roller 20 is displaced upward by the pressing body displacing means 22, and the printing paper P is continuously pressed against the master 70 on the plate cylinder 68 by the press roller 20, whereby the ink in the plate cylinder 68 is transferred. The master 70 that oozes out from the perforated portion of the master 70 and is wound around the plate cylinder 68 comes into close contact with the plate cylinder 68 and is transferred to the printing paper P for printing.

  The printing paper P after printing is peeled off from the plate cylinder 68 by the peeling claw 75, guided to the paper transport device 84 as the plate cylinder 68 rotates, and discharged from the paper transport device 84 to the paper discharge tray 85 for loading. Is done. The printing process is repeated until printing of the number of prints set with the numeric keypad 93 is completed. After that, the stencil printing apparatus 100 shifts to a standby mode in order to save power consumption when an operation such as pressing of the plate making start key is not performed for a predetermined time.

  When the printing paper P is discharged onto the paper discharge tray 85, it first contacts the airbag 34. At this time, since the airbag 34 is inflated by the air supply fan 35, the leading edge of the printing paper P is in the air. The sound when contacting the bag 34 is prevented or alleviated, and a good environment for the operator is maintained.

  That is, the stencil printing apparatus 100 discharges the printing paper P at a relatively high speed even though it is affected by the setting by the printing speed setting key 94, so that a relatively loud sound is generated when contacting the paper discharge tray 85. In addition, since this sound is generated discontinuously and suddenly, it may become a psychologically alarming noise for the operator. However, by providing the airbag 34, the sound is greatly reduced, A good environment for the operator is maintained. It was confirmed that the sound reduction effect was greater than that of the conventional sponge and elastic plate already described.

  Although the air bag 34 buffers such sound, since the elasticity is low and the resilience is low, the printing paper P in contact with the air bag 34 does not rebound greatly, and the interval is large in the width direction B of the printing paper P. The side fence 33 is positioned in the width direction and dropped while being aligned, and is stacked on the discharge tray 31 in an orderly and good state. In this embodiment, it has been confirmed that the elasticity and resilience of the airbag 34 are lower than those of the sponge and elastic plate already described.

  The basic configuration and operation of the paper discharge tray 85 are as described above. The paper discharge tray 85 is provided for the purpose of improving its function as a buffer member and improving the stackability of the printing paper P. Various other features are provided. This will be described below.

  As shown in FIGS. 1 and 4, the cushioning surface 38 of the airbag 34 has an overhang shape. The air bag 34 has a substantially flat shape in which the upper side is more inflated than the lower side, and the cushioning surface 38 has a distance from the end fence 32 that is larger in the upper side than the lower side. As described above, the airbag 34 is overhanging with respect to the vertical plane and warped as a whole, in other words, has an undercut shape.

  Therefore, when the printing paper P after the leading edge abuts against the buffer surface 38 falls, even if the leading edge portion of the printing paper P has a curved surface, the leading edge is not prevented from being caught by the airbag 34. Thus, the drop is smoothly performed, the drop position of the print paper P is stabilized, and the alignment of the print paper P on the paper discharge tray 85 is improved. In FIG. 1 and FIG. 4, the shape of the overhang is formed by the flat buffer surface 38, but the buffer surface 38 may be a curved surface such as a concave curved surface.

  As described above, since the airbag 34 has low elasticity and low resilience, the printing paper P that is in contact with the cushioning surface 38 has its leading end at the cushioning surface 38 when the cushioning surface 38 is parallel to the vertical surface. Although it is easy to fall while being touched, since the buffer surface 38 is overhanging, the leading edge of the printing paper P in contact with the buffer surface 38 is easily separated from the buffer surface 38. Therefore, in the present embodiment using the air bag 34 having low elasticity and low resilience compared to conventional sponges and elastic plates, it is significant that the buffer surface 38 is overhanged.

  In this embodiment, since the end fence 32 is suspended from the paper discharge tray 31 arranged substantially horizontally, the distance of the buffer surface 38 from the end fence 32 increases upward. However, the buffer surface 38 only needs to be overhanged with respect to the vertical surface. For example, when the end fence 32 itself is in an overhang shape, the distance of the buffer surface 38 from the end fence 32. May be uniform.

The buffer surface 38 is made of a material having smoothness. That is, the material of the airbag 34 is a low friction material having a smooth surface. Specifically, a material having a smooth touch such as silk fabric is selected. In addition, a material such as a parachute cloth may be used. The cushioning surface 38 may be configured by attaching a smooth material different from the material of the airbag 34 to the airbag 34, but considering the noise reduction and the like, the material of the airbag 34 itself It is preferable that the surface is made of a material having smoothness. Moreover, it is desirable that the material is a woven fabric in relation to the air permeability described later. In the case of a woven fabric, a weaving method such as plain weave twill is desirable.
Since the buffer surface 38 is made of a smooth material and has low friction, the same effect as that obtained by making the buffer surface 38 overhang can be obtained.

  The buffer surface 38 is made of a material having air permeability. That is, the material of the airbag 34 is a material having air permeability on the surface. Specifically, it is desirable to select a material having a stitch, which is a woven fabric such as a silk fabric or a parachute fabric, taking into account that it also has smoothness. However, the material of the airbag 34 itself may be a material that does not have air permeability such as vinyl, and may have a large number of minute holes formed therein. Thus, the material of the airbag 34 is comprised with the material which has air permeability. The amount of air escape due to air permeability is smaller than the amount of air supplied by the air supply fan 35, and the airbag 34 is maintained in its expanded state when necessary. In consideration of the escape of air, the airbag 34 may be sealed at portions other than the buffer surface 38.

  Since the cushioning surface 38 is made of a breathable material, when the leading edge of the printing paper P abuts, the air in the airbag 34 escapes to the outside at the abutting portion and its peripheral portion, thereby providing a cushioning function. The shock absorption is improved and the elasticity is lowered to reduce the resilience, and the surface resistance is lowered by the escape of air from the entire buffer surface 38, so the sound at the time of contact is reduced and printing is performed. Bounce and catching of the paper P are also reduced, and the alignment of the printing paper P is improved.

  The degree of air permeability of the buffer surface 38 In other words, the air permeability may be non-uniform and have a distribution. Specifically, as shown in FIG. 5, in the vertical direction, the air permeability of the portion where the leading edge of the printing paper P abuts or the peripheral portion in addition to this is made larger than the air permeability of other portions. In the up-down direction of the buffer surface 38, the portion where the leading edge of the printing paper P abuts is substantially constant. Therefore, by increasing the air permeability of this portion, the above-described buffering function is improved, and the effect of reducing the catch of the printing paper P can be obtained. Further, the amount of air escaped at other portions is reduced, and the energy required for driving the air supply fan 35, that is, power consumption, is reduced.

  Further, the air permeability distribution may be provided in the width direction B of the printing paper P. Specifically, the air permeability at the center of the buffer surface 38 in the width direction B of the printing paper P is made larger than the air permeability at both ends. Thereby, the buffering action starts from such a central portion having high air permeability and gradually spreads over the entire width direction B.

  Therefore, as compared with the case where the buffering action is performed in the entire width direction B from the beginning, the time during which the buffering action is generated becomes longer, and the sound at the time of contact is further reduced. Further, if the paper discharge is performed with center alignment, the buffering action always starts from the central portion of the front end of the printing paper P, so that there is an advantage that the printing paper P of various sizes can be handled. There is also an advantage that the energy required for driving the air supply fan 35 is reduced.

  Further, when the air permeability distribution is provided in the width direction B of the printing paper P, the air permeability at both ends of the buffer surface 38 in the width direction B of the printing paper P may be larger than the air permeability of the central portion. . At this time, the buffering action starts from both end portions having high air permeability and gradually spreads over the entire width direction B.

  Therefore, also in this case, compared with the case where the buffering action is performed in the entire width direction B from the beginning, the time during which the buffering action is generated becomes longer, and the sound at the time of contact is further reduced. Further, since the buffering action starts from both ends of the front end of the printing paper P, the elastic force and the repulsive force that can be generated simultaneously with the buffering action are generated at two places such as the both ends of the printing paper P. However, there is an advantage that the printing paper P is hardly inclined and the printing paper P is well aligned. There is also an advantage that the energy required for driving the air supply fan 35 is reduced.

  As a configuration that obtains the same effect as the distribution of air permeability in the width direction B of the printing paper P, the shape of the buffer surface 38 in the width direction B of the printing paper P may be a non-planar shape. Specifically, as shown in FIG. 6, the central portion in the width direction B is formed as a shape corresponding to the case where the air permeability at the center in the width direction B of the printing paper P is larger than the air permeability at both ends. As a shape corresponding to the case where the air permeability at both ends in the width direction B of the printing paper P is made larger than the air permeability at the center, as shown in FIG. The structure which makes the both ends in B convex shape is mentioned. In addition, regarding the point of reducing the energy required for driving the air supply fan 35, the same advantage can be obtained when the internal volume of the airbag 34 is reduced as a result of these shapes.

  As a configuration having the advantage of reducing the energy required for driving the air supply fan 35, there is a configuration in which the airbag 34 is divided in the width direction B of the printing paper P as shown in FIGS. With such a configuration, each portion of the airbag 34 has a columnar shape that is long in the up-down direction, and each has an advantage that the stability and strength of the shape when inflated are improved. Regarding the advantage of such energy reduction, since the strength is improved by making each part of the airbag 34 a bone-shaped structure with such a columnar shape, a buffer function is exhibited even if the internal pressure is low, Each buffer surface 38 has a convex shape in the width direction B of the printing paper P, and the internal volume is greatly reduced.

  Further, the configuration shown in FIG. 9 corresponds to the configuration shown in FIG. 6, and the configuration shown in FIG. 10 corresponds to the configuration shown in FIG. The above-described advantages are also obtained by the configuration shown in FIG.

  In the configuration shown in FIGS. 8 to 10, it is desirable to provide a plurality of air supply fans 35 and exhaust valves 36 corresponding to each part of the airbag 34. In particular, in the configuration shown in FIGS. 9 and 10, the internal volume of each part is different, and therefore it is desirable to independently control a plurality of air supply fans 35 and exhaust valves 36 arranged.

  The number of divisions is three in the examples shown in FIGS. 8 to 10, but may be two or four or more, and a configuration corresponding to FIGS. 6 and 7 may be printed. It is desirable that the odd number is set so as to be symmetric with respect to the center in the width direction B of the paper P.

  6 to 10 also preferably have an overhang shape in the vertical direction. This is because the above-described advantages due to the overhang shape can be obtained similarly.

  The buffer surface 38 is preferably subjected to antistatic processing for preventing charging due to contact and separation between the airbag 34 and the printing paper P and accumulation of static electricity. This is because the charge and static electricity accumulation deteriorates the alignment of the printing paper P on the paper discharge tray 31, and in the worst case, jamming of the printing paper P may occur on the paper discharge tray 31. By applying antistatic processing, these problems are prevented or suppressed. Such processing is performed by coating a material having antistatic properties.

  However, such processing may deteriorate with time due to contact of the printing paper P or the like. Therefore, in addition to or instead of processing the buffer surface 38, the buffer surface 38 is preferably made of a conductive material. By making the material of the buffer surface 38 a conductive material, there is an advantage that the above-mentioned problems due to charging and accumulation of static electricity are prevented or suppressed, and deterioration over time is suppressed. Maintained.

  In order to impart conductivity to the buffer surface 38, a conductive material such as conductive carbon fiber or metal fiber is introduced into at least a portion of the airbag 34 that constitutes the buffer surface 38. As an introduction method, in the case where the airbag 34 is made of a woven fabric as described above, a method of weaving a fiber made of a material related to the airbag 34 or a method of forming a fiber by a method such as sputtering of a conductive material layer For example, when the airbag 34 is formed of a material such as vinyl as described above, fibers such as fibers, carbon powder, conductive powder such as metal powder, and the like are mixed. The method etc. are mentioned.

  The control unit 90 operates the air supply fan 35 during an image forming operation, that is, during a printing operation. The air supply fan 35 only needs to keep the airbag 34 inflated when the printing paper P comes into contact with the airbag 34. When the printing paper P does not come into contact with the airbag 34, the air supply fan 35 is in the air-free state. The bag 34 does not need to be inflated, and driving the air supply fan 35 even during a non-printing operation is a waste of energy.

  In addition, during the printing operation, sound is generated by driving each part of the stencil printing apparatus 100, so that the driving sound of the air supply fan 35 does not stand out so much, but during the non-printing operation, the driving sound of the air supply fan 35 can be heard well. Since it can be annoying, it is advantageous in terms of noise reduction to stop the air supply fan 35 during the non-printing operation.

  Therefore, the control unit 90 does not interlock the start of driving of the air supply fan 35 with the power-on of the stencil printing apparatus 100, and operates the air supply fan 35 only during the printing operation to inflate the airbag 34 only when necessary. Let Specifically, the control unit 90 starts driving the air supply fan 35 simultaneously with the start of the above-described printing process, and the last print sheet P out of the number of sheets set by the ten key 93 by the above-described sheet detection device is set. The drive of the air supply fan 35 is stopped after a predetermined time has elapsed after detection. The predetermined time is set to a time sufficient for the last printing paper P to be stacked on the paper discharge tray 31 and to be stable in consideration of the printing speed. Thus, the control unit 90 functions as a gas supply unit drive control unit that operates the air supply fan 35 during the printing operation.

  The driving of the air supply fan 35 may be started when the plate making start key 92 is pressed or when the plate making is finished, and the driving of the air supply fan 35 may be stopped when the standby mode is shifted. Although it is good, it is preferable that the airbag 34 is in contact with the printing paper P so that it is inflated when necessary, and the drive of the air supply fan 35 is made as short as possible.

  The control unit 90 uses the characteristic value of the air supply fan 35, specifically, the amount of gas supplied from the air supply fan 35 to the airbag 34, that is, the air supply amount per unit time, as the image forming condition, that is, the printing condition. It is designed to change accordingly. This is because, since the kinetic energy of the printing paper P when contacting the airbag 34 differs depending on the thickness, size, printing speed, and the like of the printing paper P, the required buffer function, that is, the shock absorption characteristic changes.

  Therefore, the control unit 90 supplies the air supply fan to adjust the amount of gas supplied to the airbag 34 according to the required buffer function, that is, according to the thickness, size, printing speed, etc. of the printing paper P. The rotational speed of 35 is changed, the air pressure in the airbag 34 is adjusted, and the bulge and tension of the airbag 34 are adjusted. The rotation speed of the air supply fan 35 is adjusted by adjusting the applied voltage, PWM, control duty, or the like. In this way, the control unit 90 functions as a gas supply amount condition control unit that changes the amount of gas supplied to the airbag of the air supply fan 35 in accordance with image forming, that is, printing conditions.

  For the same purpose, the control unit 90 adjusts the air pressure in the airbag 34 and adjusts the cushioning function of the airbag 34 by adjusting the degree of inflation and tension of the airbag 34. The discharge amount, that is, the exhaust amount per unit time, may be changed in accordance with image forming conditions such as the thickness, size, and printing speed of the printing paper P, that is, printing conditions. The amount of air discharged by the exhaust valve 36 is adjusted by PWM, control duty adjustment, or the like. Here, the control unit 90 functions as a gas discharge amount condition control means for changing the amount of air discharged by the exhaust valve 36 according to the printing conditions.

  In order to adjust the air pressure in the air bag 34 for the same purpose and adjust the cushioning function of the air bag 34 by adjusting the degree of inflation and tension of the air bag 34, the paper discharge table 85 is shown in FIG. Further, an air supply adjusting valve 39 that is an electromagnetic valve as a gas introduction amount adjusting means for adjusting the amount of air supplied to the air bag 34 by the air supply fan 35 may be provided. .

  The air supply adjusting valve 39 is disposed in the above-described hole formed in the end fence 32 and formed by the air supply fan 35 and passes through the air bag 34 toward the airbag 34. Air introduction to 34 is blocked. Energization of the air supply adjustment valve 39 is performed by a control unit 90 as a gas supply amount condition control means, and the amount of air introduced into the airbag 34 by the air supply adjustment valve 39 by the control unit 90, that is, unit time. The adjustment of the amount of introduction per unit is controlled.

  The introduction amount is adjusted according to image forming conditions such as the thickness, size, and printing speed of the printing paper P, that is, printing conditions. The amount of air introduced by the air supply adjustment valve 39 is adjusted by adjusting the PWM, the control duty, or the like. As shown in FIGS. 8 to 10, a plurality of air supply adjustment valves 39 are provided corresponding to each part of the airbag 34 in the configuration in which the airbag 34 is divided in the width direction B of the printing paper P. May be.

  The adjustment of the air supply amount, the adjustment of the exhaust amount, and the adjustment of the introduction amount are the same in the configuration in which the airbag 34 is divided in the width direction B of the printing paper P as shown in FIGS. Done. In such a configuration, when a plurality of air supply fans 35, exhaust valves 36, and air supply adjustment valves 39 are provided corresponding to each part of the air bag 34, the respective air supply fans 35, exhaust valves are provided. 36, the air supply amount, the exhaust amount, and the introduction amount of the air supply adjustment valve 39 can be adjusted independently. This is because it is possible to inflate only a necessary portion of the divided airbag 34 according to the thickness and size of the printing paper P, the degree of curling due to lumping, the printing speed, and the like.

  The control unit 90 changes the amount of gas supplied to the air supply fan 35, that is, the amount of air supplied per unit time, when the printing paper P falls against the airbag 34 so as to pulsate the airbag 34. Thus, the buffer surface 38 is displaced by expanding and contracting. This is the same as providing the cushioning surface 38 with smoothness, air permeability, antistatic property, and conductivity so that the printing paper P falls without being caught after contacting the airbag 34. This is for the purpose.

  Even if the printing paper P comes into contact with the airbag 34 and is caught by the airbag 34 during the fall, this is prevented by the pulsation of the buffer surface 38 that is the skin of the airbag 34, in other words, vibration, and the printing paper P Promote the fall of. The optimum period of vibration is 5 to 60 Hz. Therefore, the amount of air supplied by the air supply fan 35 is periodically changed in such a period, the air pressure in the airbag 34 is periodically changed, and the degree of inflation and tension of the airbag 34 is periodically changed.

  The change in the amount of air supplied by the air supply fan 35 can be exemplified by periodically changing the rotational speed of the air supply fan 35 by adjusting the voltage applied to the air supply fan 35, PWM, control duty, etc. The air supply fan 35 may be constituted by a plurality of air supply fans having different output characteristics, and the combination of the air supply amounts by these air supply fans may be periodically changed.

  The periodic change in the amount of air supplied by the air supply fan 35 may always be performed when the air supply fan 35 is driven, or the print paper P is placed on the paper discharge tray 31 after contacting the airbag 34. It may be performed only at the timing up to.

  In this way, the control unit 90 controls the gas supply amount variation for changing the amount of air supplied to the airbag 34 by the air supply fan 35 when the printing paper P falls in contact with the airbag 34. Functions as a means.

  For the same purpose, the controller 90 periodically modulates the air pressure in the airbag 34 and oscillates the buffer surface 38 to promote the fall of the printing paper P, so that the control unit 90 discharges air by the exhaust valve 36, that is, a unit. The displacement per hour may be changed periodically. The amount of air discharged by the exhaust valve 36 is adjusted by PWM, control duty adjustment, or the like. Here, the control unit 90 functions as a gas discharge amount variation control means for changing the amount of air discharged by the exhaust valve 36 when the printing paper P falls in contact with the airbag 34.

  For the same purpose, the air supply adjustment valve 39 described above may be used to periodically adjust the air pressure in the airbag 34 and to vibrate the buffer surface 38 to promote the fall of the printing paper P. Energization of the air supply adjustment valve 39 is performed by a control unit 90 as a gas supply amount condition control means, and the amount of air introduced into the airbag 34 by the air supply adjustment valve 39 by the control unit 90, that is, unit time. The adjustment of the amount of introduction per unit is controlled. The amount of air introduced by the air supply adjustment valve 39 is adjusted by PWM, control duty adjustment, or the like.

  Such adjustment of the air supply amount, the adjustment of the exhaust amount, and the periodic adjustment of the introduction amount can be performed even in the configuration in which the airbag 34 is divided in the width direction B of the printing paper P as shown in FIGS. The same is done. In such a configuration, when a plurality of air supply fans 35, exhaust valves 36, and air supply adjustment valves 39 are provided corresponding to each part of the air bag 34, the respective air supply fans 35, exhaust valves are provided. 36, the air supply amount, the exhaust amount, and the introduction amount of the air supply adjustment valve 39 can be adjusted independently. This is because only necessary portions of the divided airbag 34 can be periodically pulsated.

  In the above description, the discharge tray 85 has the air supply fan 35 as the gas supply unit. However, the gas supply unit may be provided on the apparatus main body 67 side. An example of this is shown in FIG.

  The gas supply means shown in the figure is constituted by a suction fan 57 and a duct 86 provided in the paper transport device 84 of the paper discharge device 23. As described above, the suction fan 57 is for sucking the printing paper P onto the transport belt 58, and the exhausted air, that is, the exhaust gas is guided to the airbag 34 by the duct 86 to inflate the airbag 34.

  In this configuration, a new gas supply unit such as the air supply fan 35 is used by using unnecessary exhaust air from the suction fan 57 used in another part of the apparatus main body 67 side, that is, the sheet conveying device 84. There is an advantage that it becomes unnecessary.

  Further, in this configuration, since the duct 86 is required, the configuration using the air supply fan 35 is more advantageous in terms of size reduction and weight reduction, but the suction fan 57 is provided with a discharge tray 85. Since the paper device 23 is provided, the distance from the paper discharge tray 85 is relatively short, and the duct 86 is also relatively small, so that the increase in size due to the provision of the duct 86 is suppressed. ing.

  Although it is the structure which manages the duct 86, since a new gas supply means is unnecessary, it is advantageous also in terms of cost. However, when the gas supply means is provided not at the suction fan 57 but at another part of the apparatus main body 67, the installation cost of the air supply fan 35 is higher than the installation cost of the duct 86. It may be low.

  Even when the suction fan 57 is a gas supply unit, the above-described various configurations, controls, and the like in the case where the supply fan 35 is a gas supply unit can be applied. However, when the suction fan 57 is used, since one gas supply unit is provided for the configuration in which the airbag 34 is divided in the width direction B of the printing paper P, gas is supplied to each of the divided portions. It is difficult to arrange the means. Therefore, it is effective to use the exhaust valve 36 and the air supply adjustment valve 39 to perform independent control for each divided part.

  In the gas supply means such as the air supply fan 35 and the suction fan 57, it is desirable that the sound generated by driving has a main spectrum in a low sound range with low hearing sensitivity from the viewpoint of noise reduction. In particular, noise reduction is important for gas supply means such as the air supply fan 35 that are disposed outside the apparatus main body 67 and exposed.

  Referring to the example of the air supply fan 35 shown in FIG. 12, a relatively large fan such as the air supply fan 35 shown in FIG. 12A is shown in FIG. The sound generated by driving the air supply fan 35 having a relatively small size has a main spectrum in a low sound range having low hearing sensitivity. This is because a relatively large supply fan 35 as shown in FIG. 5A can supply sufficient air even when driven at a relatively low speed. Therefore, it is preferable to use a relatively large gas supply means such as the air supply fan 35 and the other suction fan 57 and drive at a relatively low speed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the image forming apparatus to which the present invention is applied is a stencil printing apparatus in the above-described form, but it may be a printing apparatus having another configuration, a copying machine, a facsimile, a printer, etc. These may be image forming apparatuses such as multifunction peripherals.

  When the image forming apparatus is a stencil printing apparatus, a plurality of plate cylinders may be provided. For example, color printing may be performed using a plurality of plate cylinders. The pressing body may be an impression cylinder instead of a press roller.

  Similarly, when the image forming apparatus uses a latent image carrier such as a photoconductor, a plurality of latent image carriers may be provided. For example, color printing is performed using a plurality of latent image carriers. It may be a thing.

In addition, the image forming apparatus may perform double-sided image formation by including a mechanism for reversing the sheet.
As a sheet used for image formation, in addition to plain paper generally used for copying and the like, OHP sheets, thick paper such as cards and postcards, recording media such as envelopes, and printing media can be used.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 is a front view showing an outline of a printing apparatus to which the present invention is applied and a paper discharge table provided in the printing apparatus. FIG. FIG. 2 is a block diagram showing each configuration of a control unit provided in the printing apparatus shown in FIG. FIG. 2 is a plan view of the paper discharge table shown in FIG. 1. FIG. 2 is a front view of the paper discharge table shown in FIG. 1. It is the front view which showed a mode that the airbag with which the paper discharge stand shown in FIG. 1 was equipped had air permeability, and the air permeability is non-uniform | heterogenous. 1 shows that the surface of the air bag provided in the paper discharge tray shown in FIG. 1 on the side where the leading edge of the sheet abuts is a non-planar shape, and the central portion in the width direction of the sheet is a convex shape. It is a top view. 1 shows that the surface of the airbag provided on the paper discharge tray shown in FIG. 1 on the side where the leading edge of the sheet abuts is a non-planar shape, and both end portions in the width direction of the sheet are convex. It is a top view. FIG. 2 is a plan view showing that the airbag provided in the paper discharge tray shown in FIG. 1 is divided into a plurality of parts in the sheet width direction. The airbag provided in the paper discharge tray shown in FIG. 1 is divided into a plurality of sheets in the width direction of the sheet, and the surface of the airbag on the side where the leading edge of the sheet contacts is non-planar, It is a top view which shows that the center part in the width direction of a sheet | seat has comprised the convex shape. The airbag provided in the paper discharge tray shown in FIG. 1 is divided into a plurality of sheets in the width direction of the sheet, and the surface of the airbag on the side where the leading edge of the sheet contacts is non-planar, It is a top view which shows that the both ends in the width direction of a sheet | seat are forming the convex shape. FIG. 3 is a schematic front view illustrating an example in which a gas supply unit is provided on the image forming apparatus main body side. It is a side view for demonstrating that it is preferable that a gas supply means is comparatively large.

Explanation of symbols

34 Airbag 35 Gas supply means 36 Gas discharge means 38 Surface of the airbag on the side where the leading end of the sheet abuts 39 Gas introduction amount adjustment means 57, 86 Gas supply means 85 Paper discharge table 90 Gas supply means drive control means, gas Supply amount condition control means, gas discharge amount condition control means, gas supply amount fluctuation control means, gas discharge amount fluctuation control means 100 Image forming apparatus B Sheet width direction P Sheet

Claims (31)

In the paper delivery tray where the sheets on which image formation has been performed are stacked,
Front end of the sheet which has moved toward the discharge tray is closed the air bag abuts,
In the airbag, the gas for inflating the airbag is supplied by a gas supply unit provided on the sheet discharge table or the main body side of the image forming apparatus having the sheet discharge table. . In the paper discharge stand according to claim 1,
The sheet discharge table according to claim 1, wherein a surface of the airbag on a side where a front end of the sheet contacts has a non-planar shape. In the paper discharge stand according to claim 2,
The sheet discharge table according to claim 1, wherein a surface of the airbag on the side where the leading edge of the sheet abuts has a convex shape at the center in the sheet width direction. In the paper discharge stand according to claim 2,
2. A sheet discharge table according to claim 1, wherein both sides of the airbag in the width direction of the sheet are convex. In the paper discharge stand according to any one of claims 1 to 4,
The paper discharge table, wherein the airbag is divided into a plurality of parts in the width direction of the sheet. In the paper discharge stand according to any one of claims 1 to 5,
The discharge table according to claim 1, wherein a surface of the airbag on the side where the front end of the sheet abuts has an overhang shape. In the paper discharge stand according to any one of claims 1 to 6,
The discharge table according to claim 1, wherein a surface of the airbag on the side where the leading end of the sheet abuts is made of a material having smoothness. In the paper discharge stand according to any one of claims 1 to 7,
The discharge table according to claim 1, wherein a surface of the airbag on a side where a front end of the sheet contacts is made of a material having air permeability. The paper discharge tray according to claim 8.
The paper discharge table according to claim 1, wherein the air permeability of the surface of the airbag on the side where the leading edge of the sheet contacts is non-uniform. In the paper discharge stand according to claim 9,
A sheet discharge table according to claim 1, wherein the air permeability of the portion of the surface of the airbag on the side where the front end of the sheet abuts in the vertical direction is higher than that of other portions. In the paper discharge stand according to claim 9 or 10,
A sheet discharge table, wherein the air permeability of the central portion in the sheet width direction of the surface of the airbag on the side where the leading edge of the sheet abuts is greater than the air permeability of both ends in the sheet width direction. In the paper discharge stand according to claim 9 or 10,
2. A paper discharge table according to claim 1, wherein air permeability at both ends in the sheet width direction of the surface of the airbag on the side where the front end of the sheet abuts is greater than the air permeability at the center in the sheet width direction. In the paper discharge stand according to any one of claims 1 to 12,
An ejection stand, wherein an antistatic process is performed on a surface of the airbag on a side where a front end of a sheet contacts. In the paper discharge stand according to any one of claims 1 to 13,
The sheet discharge table according to claim 1, wherein a surface of the airbag on a side where a front end of the sheet contacts is made of a conductive material. In the paper discharge stand according to any one of claims 1 to 14,
A paper discharge stand comprising gas discharge means for discharging the gas in the airbag. The paper discharge tray according to claim 15,
A paper discharge stand comprising gas discharge amount condition control means for changing a gas discharge amount by the gas discharge means in accordance with image forming conditions. In the paper discharge stand according to claim 15 or 16,
A paper discharge table, comprising: a gas discharge amount variation control means for changing the amount of gas discharged by the gas discharge means when the sheet falls in contact with the airbag. In the paper discharge stand according to any one of claims 1 to 17,
A discharge stand comprising the gas supply means .   An image forming apparatus comprising the paper discharge table according to claim 1.   An image forming apparatus comprising the paper discharge table according to claim 18. The image forming apparatus according to claim 19.
An image forming apparatus comprising: the gas supply unit on the image forming apparatus main body side, wherein the gas supply unit is also used in another part on the image forming apparatus main body side. The image forming apparatus according to claim 20 or 21,
An image forming apparatus comprising gas supply means drive control means for operating the gas supply means during an image forming operation. The image forming apparatus according to any one of claims 20 to 22,
An image forming apparatus comprising: a gas supply amount condition control unit configured to change an amount of gas supplied to the airbag of the gas supply unit according to an image forming condition. 24. The image forming apparatus according to claim 23.
A gas introduction amount adjusting means for adjusting an amount of gas supplied to the airbag by the gas supply means;
An image forming apparatus, wherein the gas supply amount control means controls the adjustment of the amount of gas introduced into the airbag by the gas introduction amount adjustment means. 25. The image forming apparatus according to any one of claims 20 to 24, wherein:
An image forming apparatus comprising: a gas supply amount variation control unit configured to change the amount of gas supplied to the airbag by the gas supply unit when the sheet contacts and falls on the airbag. . The image forming apparatus according to claim 25.
A gas introduction amount adjusting means for adjusting an amount of gas supplied to the airbag by the gas supply means;
An image forming apparatus, wherein the gas supply amount variation control means controls adjustment of the amount of gas introduced into the airbag by the gas introduction amount adjustment means. The image forming apparatus according to claim 24 or 26, wherein:
In the image forming apparatus in which the airbag is divided into a plurality in the width direction of the sheet,
A plurality of the gas introduction amount adjusting means corresponding to each of the divided airbags, and the amount of gas introduced into the airbag by each gas introduction amount adjusting means is adjusted independently. An image forming apparatus. The image forming apparatus according to any one of claims 20 to 27, wherein:
In the image forming apparatus in which the airbag is divided into a plurality in the width direction of the sheet,
An image forming apparatus comprising a plurality of the gas supply means corresponding to each of the divided airbags, wherein the gas supply amount by each gas supply means is adjusted independently. An image forming apparatus according to any one of claims 19 to 28, wherein:
In the image forming apparatus, wherein the airbag is divided into a plurality of sheets in the width direction of the sheet and has a gas discharge unit that discharges the gas in the airbag.
An image forming apparatus comprising a plurality of the gas discharge means corresponding to each of the divided airbags, and the amount of gas discharged by each gas discharge means is adjusted independently. The image forming apparatus according to any one of claims 20 to 29,
The image forming apparatus according to claim 1, wherein the gas supply means has a main spectrum in a low frequency range where the sound generated by driving is low in hearing sensitivity.   A sheet stacking method for stacking sheets on the sheet discharge table using the sheet discharge table according to any one of claims 1 to 18 or the image forming apparatus according to any one of claims 19 to 29.

Images