JP2007112553A - Air blowing device, paper feeding cassette and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device capable of dealing with sheets difficult to be fed such as coated paper without increasing the size of a relatively small paper feeding cassette provided inside an image forming device such as a copying machine. <P>SOLUTION: This air blowing device for blowing air to a sheet bundle stacked on the paper feeding cassette having a sheet stacking means to stack sheets is provided with a blowing device main body; an air intake port and air blowing port provided in the blowing device main body; and an air blowing means provided inside the blowing device main body and blowing air taken in from the air intake port from the air blowing port. When the air blowing means attachable to/detachable from the paper feeding cassette is attach to the paper feeding cassette, the air blowing means blows air to the side face of the upper portion of the sheet bundle stacked on the sheet stacking means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air blowing device, a paper feed cassette, and an image forming apparatus.

  Conventionally, in image forming apparatuses such as copying machines and printers, cut sheets that can be continuously fed are usually limited to high-quality paper and plain paper designated by the copying machine manufacturer. Conventionally, various separation methods have been adopted in order to reliably separate and feed such sheets one by one.

  For example, there is a retard separation system in which a pick-up roller is brought into contact with and pressed on the uppermost sheet of a sheet bundle and sent out, and a feed roller and a separation roller arranged on the downstream side in the sheet conveying direction prevent double feeding of sheets. Are known. The separation roller is driven in a direction opposite to the sheet conveying direction with a predetermined torque, and abuts and presses the feed roller driven in the sheet feeding direction with a predetermined pressure. Further, various separation methods such as a separation pad method in which a friction member is brought into contact with the feed roller with a predetermined pressure to prevent double feeding are employed. In order to reliably separate and feed the paper by these methods, for example, in the case of the retard method, the return torque and the applied pressure are optimized in consideration of the frictional force of the paper to be fed. By this optimization, it was possible to reliably separate and feed one sheet at a time from the sheet bundle.

  On the other hand, in recent years, with the diversification of recording media, in addition to ultra-thick paper, OHP sheets, art films, etc., in order to obtain whiteness and gloss from the demands of colorization, coated paper, etc., whose surface is coated There is an increasing demand for image formation on sheets.

  However, in the case of ultra-thick paper, its own weight becomes a conveyance resistance and cannot be picked up and non-feed occurs. In addition, in the case of a sheet made of a resin material that is easily charged, such as an OHP sheet or an art film, the sheet surface is gradually charged by rubbing between sheets during a sheet feeding operation in a low humidity environment, and the sheets are adhered to each other by Coulomb force. A non-feed or double feed occurs. In addition, coated paper with paint applied on the surface of the paper has the property of adsorbing sheets when the sheets are stacked in a highly humid environment. The problem of frequent multiple feeds arises.

  These problems occur because only the frictional force between the sheets is considered in the conventional separation method. In the case of the special sheet as described above, the frictional force itself between the sheets is equal to or less than that of the plain paper described above. However, the adsorption force due to frictional charging of the resin material sheet in a low humidity environment and the adsorption force of coated paper in a high humidity environment are much stronger than the frictional force between sheets, so separation by the conventional separation method I can't finish it.

  In order to solve such very strong adsorption, auxiliary air blowing means is provided to blow the sheets in advance by blowing air from the side of the sheet bundle. Some copiers adopt a paper feeding method. In this system, air is blown from the side surface of the sheet bundle to eliminate the adsorption between the sheets, and the sheets are picked up and separated one by one by a separation unit provided downstream thereof. In the paper feeding method equipped with the auxiliary air blowing means, even if a material having a strong adsorbing force as described above is used as compared with a generally used friction separation type device, the sheet is spread before the paper feeding and the suction is performed. The paper feed can be separated.

  Many proposals related to a sheet feeding method provided with such auxiliary air blowing means have been made (see, for example, Patent Document 1). As an example, in the sheet feeding device 155 shown in FIG. 8, a sheet feeding tray 156 for stacking sheets, a sheet feeding unit that feeds sheets from the sheet feeding tray 156, and the side surfaces of the stacked sheets on the side surfaces of the sheets. An air blowing means 71 for blowing air from a vertical direction and a flow path moving means 157 for moving a flow path of air blown from the air blowing means 71 in the direction perpendicular to the sheet surface are provided.

  The flow path moving means 157 includes a guide rail (not shown) that supports the air blowing means 71 so as to be movable in the vertical direction, an electric motor 121, and is fixed to the output shaft of the electric motor 121 and slides on the lower surface of the air blowing means 71. And a cam plate 123 for moving the air blowing means 71 in contact therewith. Accordingly, when the electric motor 121 rotates and the cam plate 123 rotates, the entire air blowing means 71 moves in the vertical direction.

  The air blowing means 71 is moved so that the opening (air outlet) of the air blowing means 71 covers the upper end of the sheet. As a result, the upper sheet is levitated and the adsorption between the sheets can be released.

Furthermore, the sheet is dehumidified by heating the blown air with a heater (hereinafter referred to as “auxiliary hot air air blowing means”), and there is also a type that relieves the adsorptive power of the coated paper particularly in a high humidity environment (for example, Patent Document 2).
JP-A-11-5543 JP 2001-48366 A

  However, a sheet feeding apparatus that employs the auxiliary air blowing means or the auxiliary hot air air blowing means as described above requires devices such as air blowing means, heater means, and an electric motor. Therefore, the size of the apparatus is increased, and until now, the apparatus has been adopted for a relatively large sheet feeding deck having a capacity of about 2000 to 4000 sheets.

  When such a sheet feeding apparatus is applied to an image forming apparatus such as a copying machine, the sheet feeding apparatus can be used only in a high-speed and high-end model capable of mounting an external large-sized sheet feeding deck. That is, in a relatively low / medium speed class model in which a large sheet feeding deck cannot be mounted, it is difficult to reliably feed sheets that are difficult to feed as described above, which is inconvenient for the user.

  The present invention has been made in view of the above circumstances, and provides a technique capable of appropriately separating and feeding a sheet that is highly difficult to feed, such as coated paper, without increasing the size of the image forming apparatus. For the purpose.

In order to solve the above-described problems, the present invention provides an air blowing device that is detachably provided in a sheet feeding cassette having a sheet stacking unit for stacking sheets, and that blows air onto a sheet bundle stacked on the sheet stacking unit. Because
A spraying device body,
An air inlet and an air outlet provided in the spraying device body;
Air blowing means provided inside the spraying device main body, for blowing air taken in from the air inlet from the air outlet,
Have
When attached to the sheet feeding cassette, the air blowing means blows air to an end portion of the sheet bundle stacked on the sheet stacking means.

  According to the present invention, it is possible to appropriately separate and feed a sheet that is difficult to feed, such as coated paper, without increasing the size of the image forming apparatus.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a printer that is an example of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1000 denotes a printer. The printer 1000 includes a printer main body 900 and a scanner 2000 disposed on the upper surface of the printer main body 900.

  Here, a scanner 2000 that reads a document is processed by a scanning optical system light source 201, a platen glass 202, a document pressure plate 203 that opens and closes, a lens 204, a light receiving element (photoelectric conversion) 205, an image processing unit 206, and an image processing unit 206. A memory unit 208 for storing the image processing signals.

  When reading an original, the original (not shown) placed on the platen glass 202 is read by irradiating light with a scanning optical system light source 201. Then, the read document image is processed by the image processing unit 206, converted into an electrically encoded electric signal 207, and transmitted to the laser scanner 111 as an image forming unit. Note that image information processed and encoded by the image processing unit 206 may be temporarily stored in the memory unit 208 and transmitted to the laser scanner 111 as necessary by a signal from the controller 120 described later.

  The printer main body 900 includes a sheet feeding device 1001 to 1004 that feeds the sheet S, a sheet feeding device 902 that feeds the sheet S fed by the sheet feeding device 1001 to 1004 to the image forming unit 901, and a printer 1000. A controller 120, which is a control means for controlling

  Here, the sheet feeding apparatuses 1001 to 1004 all have the same configuration. The sheet feeding apparatus 1001 will be described as a representative. A sheet feeding apparatus 1001 includes a cassette 10, a pickup roller 11, and a separation unit. The separation unit includes a feed roller 12 and a retard roller 13. The sheets S in the cassette 10 are separated and fed one by one by the action of the pickup roller 11 that moves up and down / rotates at a predetermined timing and the separation unit. A paper feed sensor 14 is provided in the vicinity of the feed roller 12 and the retard roller 13 on the downstream side in the sheet conveying direction, and the paper feed sensor 14 can detect the passage of the sheet S.

  The sheet conveying device 902 includes a conveying roller pair 15, a pre-registration roller pair 130, and a registration roller pair 110. The sheet S fed from each of the sheet feeding apparatuses 1001 to 1004 is guided to the registration roller pair 110 after passing through the sheet conveyance path 105 constituted by the guide plate by the conveyance roller pair 15. . Further, the sheet S is thereafter conveyed to the image forming unit 901 by the registration roller pair 110.

The image forming unit 901 includes a photosensitive drum 112, a laser scanner 111, a developing device 114, a transfer charger 115, a separation charger 116, and the like. During image formation, the laser scanner 1
11 is applied to the photosensitive drum 112 which is turned back by the mirror 113 and rotates clockwise. A latent image is formed at the exposure position irradiated with the laser light, and the latent image is visualized as a toner image by the developing device 114.

  The toner image on the photosensitive drum 112 is then transferred to the sheet S by the transfer charger 115 in the transfer unit 112b. Further, the sheet S having the toner image transferred thereon is electrostatically separated from the photosensitive drum 112 by the separation charger 116. The sheet S is further transported to the fixing device 118 by the transport belt 117 to fix the toner image, and then is discharged by the paper discharge roller 119. Further, a paper discharge sensor 119a is provided in the conveyance path between the fixing device 118 and the paper discharge roller 119, and the passage of the sheet S discharged by the paper discharge sensor 119a can be detected.

  In this embodiment, the printer main body 900 and the scanner 2000 are separate, but the printer main body 900 and the scanner 2000 may be integrated. The printer main body 900 functions as a copying machine when a processing signal of the scanner 2000 is input to the laser scanner 111, and functions as a FAX when a reception signal of FAX is input to the laser scanner 111. Furthermore, if an output signal of a personal computer is input, it functions as a printer.

  Conversely, if the processing signal of the image processing unit 206 of the scanner 2000 is transmitted to another FAX, it functions as a FAX. Further, if the scanner 2000 is equipped with an automatic document feeder 250 as shown by a two-dot chain line in place of the document pressure plate 203, the document can be automatically read.

  Next, a detailed description will be given of the paper feed cassette unit when plain paper or the like is used (normal time) in the printer 1000 according to the present embodiment. When using plain paper or the like, the sheet feeding unit in the present embodiment has a sheet feeding cassette configuration that employs a retard separation system that is a conventional technique. As described above, the sheet feeding apparatuses 1001 to 1004 in the present embodiment have the same configuration, and the sheet feeding cassettes 10, 20, 30, and 40 provided in the respective embodiments have the same configuration. Will be described.

  2 is a plan view showing the configuration of the paper feed cassette 10, and FIG. 3 is a main cross-sectional view thereof. In the present embodiment, the cassette 10 is attached to and detached from the cassette storage portion provided in the printer main body 900 from the width direction orthogonal to the sheet conveying direction.

  In FIG. 2, 51 and 52 are side regulating plates which are sheet regulating means for regulating the position of the sheet S stacked and stored in the cassette 10 in the width direction (direction orthogonal to the sheet conveying direction). The plates 51 and 52 are configured to be movable in the width direction according to the size of the sheet S. Reference numeral 53 denotes a rear end regulating plate for regulating the rear end position of the sheet S in the sheet conveying direction. The rear end regulating plate 53 is configured to be movable in the sheet conveying direction according to the size of the sheet S. ing.

  The distance between the side regulating plates 51 and 52 can be detected by the pinion gear 65, and the position of the rear end regulating plate 53 can be detected by a detecting means (not shown). The size of the sheet S can be determined from the positions of these regulating plates, and the size of the sheet S is transmitted to the controller 120.

The cassette 10 can be pulled out along a cassette rail (not shown), and when the user sets the sheet S, the cassette 10 can be pulled out from the printer body to the front side. Further, when the cassette 10 is stored in the cassette storage section, it is detected by a cassette attachment / detachment sensor (not shown). A detection signal from the cassette attachment / detachment detection sensor is transmitted to the controller 120. The controller 120 can detect whether the cassette 100 is attached to the cassette storage unit or pulled out based on a detection signal from the cassette attachment / detachment detection sensor.

  Further, in the cassette 10, as shown in FIG. 3, a sheet stacking plate 56, which is a sheet stacking means for stacking sheets S, is provided so as to be rotatable around a fulcrum 23. A lifter plate 57 for raising and lowering the plate is provided. The lifter plate 57 is attached to a lifter drive shaft 58, and is rotatable by a drive input from a lifter drive gear 59 provided on the lifter drive shaft 58. When the cassette 10 is mounted on the printer main body, drive transmission is performed from a drive source (not shown) to the lifter drive gear 59, the lifter plate 57 rotates, and the sheet stacking plate 56 is moved up and down.

  A paper surface position detection sensor 55 is provided on the upper portion of the cassette 10 to detect whether the paper surface position of the uppermost sheet stacked on the sheet stacking plate 56 is at an appropriate height for feeding. That is, it is possible to detect that the uppermost sheet has reached a position where it can be fed. When the sheet S is sequentially fed from the top in accordance with the feeding operation, the paper surface height gradually decreases, and the paper surface position detection sensor 55 is turned off, the controller 120 again turns the lifter drive gear 59 to the lifter plate 57. Drive in the direction of rising. As a result, the paper surface height can always be controlled within a certain range. The above is the configuration of the paper feed cassette when plain paper is used in the present embodiment.

  Next, this embodiment will be described with reference to FIGS. 4 to 7 in the case where it is desired to feed a sheet that is difficult to feed with a plain paper feed cassette such as thick paper or coated paper.

  FIG. 4 is a plan view showing a configuration of an air blowing device (sheet auxiliary separation kit) 300 that is mounted on a paper feeding cassette for feeding sheets that are difficult to feed such as cardboard and coated paper, and FIG. It is a perspective view. 6 and 7 are plan views when the air blowing device is mounted on the paper feed cassette.

  A housing (blowing device main body) 301 of the air blowing device 300 has a rectangular parallelepiped shape and is sized to be mounted inside the paper feed cassette. The air blowing device 300 includes an air inlet 308, a heater 309, a duct 307, fans 305 and 306, and air outlets 303a and 303b. The intake port 308 is on the rear surface in the sheet conveying direction, and the heater 309 is provided on the inflow path of air flowing in from the intake port 308. The duct 307 is provided so as to guide the air discharged from the heater 309 to the fans 305 and 306.

  By adopting such a configuration, the air blowing device 300 can efficiently take in air from an empty space in the sheet feeding cassette 10 (rear in the sheet conveyance direction). The air flowing in from the air inlet 308 is heated by the heater 309, and hot air is blown out from the air outlets 303a and 303b provided on the surface orthogonal to the sheet conveying direction via the fans 305 and 306 as air blowing means. It has a configuration that can.

  The air blowing ports 303 a and b are provided in the upper part of the air blowing device 300. By making the heights of the air outlets 303a, 303b substantially the same as the paper surface position for paper feeding, the side edge portions in the sheet width direction intersecting the sheet feeding direction of the sheet bundle loaded on the sheet stacking plate 56 Hot air can be blown to the upper part. Moreover, it is preferable that the air outlets 303a and 303b have a lattice shape or slits so that dust, foreign matter, and the like do not enter the air blowing device 300.

The procedure for mounting the air blowing device 300 to the paper feed cassette 10 will be described with reference to FIG. First, the side regulating plates 51 and 52 provided in the cassette 10 for retracting the air blowing device 300 are retracted to the maximum width. Next, the air blowing device 300 is attached to a positioning hole as an attaching means provided in the cassette 10. A plurality of positioning holes are provided in the cassette 10, and the air blowing device 300 is attached to the positioning holes matching the sheet width.

  In FIG. 6, the air blowing device 300 is attached to a place where the back side side regulation plate 52 is present, but it may be attached to a place where the near side side regulation plate 52 is located. Further, the side restriction plate 52 may be removable, and the air blowing device 300 may be attached to the place where the side restriction plate 52 is removed.

  A detection sensor for detecting that the air blowing device 300 is mounted is provided in the positioning hole in which the air blowing device 300 is mounted. With this detection sensor, the position of the air blowing device 300 can be known, and therefore the size of the sheets stacked on the cassette 10 can be detected.

  The surfaces with the air outlets 303a, b of the air blowing device 300 are flat, and the sheet is regulated in the width direction of the sheet together with the side regulating plate 51 retracted to the front side. That is, with the position of the front side restricting plate 51 as a reference, the position of the air blowing device 300 is advanced and retracted as shown in FIG.

  By using the one-side reference in this way, it is possible to increase the corresponding size in the sheet width direction as compared with the case where the center reference is used as usual. Even if the air blowing device 300 is installed, if the center reference is made, a wasteful space as large as the width of the air blowing device 300 is generated on the side where the side regulating plate 51 on the front side is present, and the size that can be handled is reduced. Because it will end up.

  Further, when it is detected that the air blowing device 300 is mounted, the controller 120 is notified. Upon receiving this notification, the controller 120 detects that the restriction in the sheet width direction has been changed to the one-side reference, and controls the printer 1000 to change the image writing position from the center reference to the one-side reference.

  Finally, the connector wire 330 is coupled to a connection cable (not shown) in the cassette housing portion provided in the printer main body 900 so that an electrical signal and a control signal of the air blowing device 300 can be transmitted and received. This connection cable is a flexible cable or the like, and always keeps an electrical connection within the range of insertion and removal of the cassette 10. Alternatively, as a drawer connector connection, an electrical connection can be made when the cassette 10 is mounted on the main body.

  In the above description, the air blowing device 300 is mounted in the positioning hole provided in the cassette 10. However, the cassette 10 may be provided with a sliding means in the sheet width direction and fixed thereto. In this way, by sliding the sliding means, the air blowing device 300 is also slid to regulate the sheet width direction. Further, the size of the sheet is detected by the detecting means for detecting the position of the sliding means. In the above description, the air blowing device is arranged so as to blow air on the side end in the width direction of the sheet. However, the present invention is not limited to this, and from the front side and the rear side in the sheet feeding direction. You may make it attach an air spraying device so that air may be sprayed on the edge part of a sheet | seat.

1 is a cross-sectional view of an image forming apparatus including a paper feed cassette according to the present embodiment. It is a top view which shows the structure of the paper feed cassette which concerns on this Embodiment. It is a main sectional view of a paper feed cassette concerning this embodiment. It is a top view of the air spraying apparatus which concerns on this Embodiment. It is a perspective view of the air spraying apparatus which concerns on this Embodiment. It is a top view at the time of mounting | wearing an air blowing apparatus with a paper feed cassette. It is a top view at the time of mounting | wearing an air blowing apparatus with a paper feed cassette. It is explanatory drawing of a prior art.

Explanation of symbols

10, 20, 30, 40 cassette (normal)
300 Air blowing device 301 Housing 303a, b Air outlet 305, 306 Fan 307 Duct 308 Air inlet 309 Heater S Sheet

Claims (9)

An air blowing device that is detachably provided in a sheet feeding cassette having a sheet stacking unit for stacking sheets and that blows air onto a sheet bundle stacked on the sheet stacking unit,
A spraying device body,
An air inlet and an air outlet provided in the spraying device body;
Air blowing means provided inside the spraying device main body, for blowing air taken in from the air inlet from the air outlet,
Have
An air blowing device, wherein the air blowing unit blows air to an end portion of a sheet bundle stacked on the sheet stacking unit when attached to the sheet feeding cassette.   2. The air blowing device according to claim 1, wherein a surface of the spraying device main body on which the air blowing port is provided also serves as a regulation surface for regulating the position of the sheets stacked on the sheet stacking unit.   The air spraying device according to claim 1 or 2, wherein the air spraying device is disposed so as to spray air to a side end portion of the sheet bundle stacked on the sheet stacking unit in a direction orthogonal to a sheet feeding direction.   The air blowing device according to any one of claims 1 to 3, wherein the air inlet is disposed on a rear surface of the blowing device main body in a sheet feeding direction. Sheet stacking means for stacking sheets;
The air spraying device according to any one of claims 1 to 4,
Mounting means for mounting the air blowing device;
A paper feed cassette characterized by comprising:   6. The sheet feeding cassette according to claim 5, wherein when the air blowing device is attached, the position of the sheets stacked on the sheet stacking unit is regulated by the air blowing device. A sheet restricting means for restricting the position of the sheet in contact with a side end portion of the sheet stacked on the sheet stacking means in a direction orthogonal to the sheet feeding direction;
When the air blowing device is attached so as to blow air on the side end portion of the sheets stacked on the sheet stacking means, the sheet restricting means is retracted to the maximum width and is applied to the sheet stacking means. 6. The position of the sheet is regulated by regulating one side edge of the stacked sheets and regulating the air blowing device in contact with the other side edge of the sheet. The listed paper cassette. A paper feed cassette according to any one of claims 5 to 7,
Image forming means for forming an image on a sheet fed from the paper feed cassette;
An image forming apparatus. It is possible to selectively set the image writing position of the image forming means to either the center reference or the one-side reference,
The image forming apparatus according to claim 8, wherein when the air blowing device is attached, the image writing position of the image forming unit is switched from a center reference to a one-side reference.

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