JP4882940B2 - Paper discharge device - Google Patents

Description

The present invention relates to HaishiSo location.

  As one of the prior arts, the following Patent Document 1 describes the position of a leading edge regulating member that regulates the leading edge position of a sheet regarding a sheet aligning mechanism for aligning sheets stacked on a stack tray that can be lifted and lowered in an elevator manner. A configuration of a paper discharge device including an adjustment unit that can be moved and adjusted according to the length is described.

  In the paper discharge device described in Patent Document 1, the trailing edge of the paper discharged on the stack tray (hereinafter also referred to as “discharge paper”) is hit from above with a rotating paddle, thereby dropping the paper. It has a structure to promote. However, the fall speed of the discharged paper varies depending on the thickness and basis weight of the paper, paper quality (stretch strength), curl state, and the like.

JP 2003-312930 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanism that can shorten the time required for the discharged paper to fall onto the paper stacking surface of the paper stacking unit and reduce variations in the required time.

According to the first aspect of the present invention, there is provided a discharge member that discharges the sheet, a sheet stacking unit on which the sheet discharged by the discharge member is stacked, a rotating fin, and the sheet discharged by the discharge member. A paddle member that promotes the fall of the sheet by hitting the rear end with the rotating fin from above, a drive unit that drives the paddle member, and an opening through which the fin passes, and is loaded on the sheet stacking unit A trailing edge regulating member for regulating the trailing edge position of the sheet to be printed, and a direction opposite to the sheet discharging direction by the discharging member from a corner portion facing the reference surface of the trailing edge regulating member and the sheet loading surface of the sheet loading portion And a discharge means for exhausting air through the opening .

  According to the first aspect of the present invention, it is possible to reduce the time required for the discharged paper to fall on the paper stacking surface of the paper stacking unit and to reduce the time required as compared with the case without this configuration. Can be reduced.

Further, according to the invention described in claim 1, without adversely affecting the sheet alignment property at the discharge direction of the sheet, it is possible to exhaust the air in the corners at the exhaust means.

Furthermore, according to the first aspect of the present invention, the opening provided in the rear end regulating member can be used for a plurality of purposes.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied. The illustrated image forming apparatus 1 includes an image forming apparatus main body 2 and a paper discharge device 3. In the image forming apparatus main body 2, two sheet feeding apparatuses 4 and 5 are incorporated in two upper and lower stages. Each of the paper feeders 4 and 5 is, for example, a paper storage unit having a tray shape, a cassette shape, a box shape, or the like, and a paper supply unit that sequentially feeds the paper stored in the paper storage unit one by one from the top. It is comprised using a roll.

  Further, the image forming apparatus main body 2 is formed with a sheet conveyance path for conveying sheets fed from the respective sheet feeding apparatuses 4 and 5. The paper transport path is formed by a transport path forming member (not shown). On the paper conveyance path, a plurality of conveyance rolls (roll pairs) 6 to 21 are provided at predetermined intervals.

  An image transfer device 22 and an image fixing device 23 are provided between the transport roll 10 and the transport roll 11 on the paper transport path. The image transfer device 22 transfers an image (toner image) onto a sheet conveyed along a sheet conveyance path. The image transfer device 22 includes a photosensitive drum 22A and a transfer roll 22B that are opposed to each other via a paper conveyance path. Although not shown, the image transfer device 22 exposes and scans the surface of the charger 22A charged to the photosensitive drum 22A and the photosensitive drum 22A charged to a predetermined potential by the charger with laser light. An image writing device for writing an electrostatic latent image and a developing device for developing the electrostatic latent image written by the image writing device using, for example, a two-component developer composed of toner and a carrier.

  The photosensitive drum 22A and the transfer roll 22B are arranged in contact with each other with a predetermined pressure. The photosensitive drum 22A is driven to rotate at a constant speed in the counterclockwise direction in the figure when an image is formed on a sheet. The transfer roll 22B rotates following the photosensitive drum 22A, sandwiches a sheet with the photosensitive drum 22A, and applies a charge having a polarity opposite to that of the toner to the sheet. The toner image is transferred onto a sheet.

  The image fixing device 23 fixes an image (toner image) on a sheet conveyed along a sheet conveyance path. The image fixing device 23 includes a heating roll 23A that is heated to a predetermined temperature (fixing temperature) by a heater or the like, and a pressure roll 23B that contacts the heating roll 23A with a predetermined pressure.

  A main body (hereinafter, referred to as a “discharge device main body”) 24 of the paper discharge device 3 has a storage space 25 for storing the image-formed paper discharged from the image forming device main body 2. The paper discharge apparatus main body 24 may be configured integrally with the image forming apparatus main body 2 or may be configured separately.

  The paper discharge device 3 includes a discharge roll 26 as a discharge member, a discharge sensor 27, and a paper stacking base 28 as a paper stacking unit. The discharge roll 26 takes in the paper transported (discharged) by the transport roll 13 in the image forming apparatus main body 2 into the paper discharge apparatus main body 24 and discharges the captured paper into the storage space 25. The discharge roll 26 is configured by using a pair of rolls, one of which is a rotational drive side and the other is a rotational driven side. The discharge roll 26 rotates in synchronization with the transport roll 13 provided on the image forming apparatus main body 2 side.

  The discharge sensor 27 detects the passage of paper (front end passage, rear end passage) in front of the discharge roll 26 (upstream side). The discharge sensor 27 is configured using, for example, a photosensor having a light emitting element and a light receiving element, and is provided in the middle of the paper transport path from the transport roll 13 to the discharge roll 26. For example, when the leading edge of the sheet passes the sensor detection position, the sensor output signal switches from the off state to the on state, and the sensor output signal is on when the trailing edge of the sheet passes the sensor detection position. Is switched to the off state. For this reason, when there is a sheet at the sensor detection position, the sheet discharge sensor 27 is held in the on state, and when no sheet exists at the sensor detection position, the sheet discharge sensor 27 is held in the off state.

  The paper stacking table 28 is for stacking paper 29 discharged by the discharge roll 26 in the accommodation space 25 in the paper discharge device main body 24. The upper surface 28A of the paper stacking base 28 is disposed in parallel with the horizontal plane. The paper stacking base 28 is formed in, for example, a tray shape, and is configured to be lifted up and down (moved up and down) in the accommodation space 25 in accordance with the driving of a lifting drive unit (not shown).

  In the image forming apparatus 1 configured as described above, a sheet fed from one of the sheet feeding devices 4 and 5 is sent to the transport roll 10 according to the rotation of the transport rolls 6, 7, 8, and 9. Next, the sheet is fed into the image transfer device 22 according to the rotation of the transport roll 10. In the image transfer device 22, the toner image is transferred to the first surface of the paper when passing between the photosensitive drum 22 </ b> A and the transfer roll 22 </ b> B.

  Next, the sheet is sent to the image fixing device 23. In the image fixing device 23, the toner image is fixed on the first surface of the paper when passing between the heating roll 23A and the pressure roll 23B. Next, the paper is sent to the transport roll 13 according to the rotation of the transport rolls 11, 12, and further sent to the discharge roll 26 according to the rotation of the transport roll 13.

  In the paper discharge device 3, the paper is discharged according to the rotation of the discharge roll 26, and the discharged paper is stacked on the paper stacking table 28. The above operation is the case of single-sided image forming processing for forming an image on one side of a sheet.

  In the case of double-sided image forming processing in which images are formed on both sides of the paper, the paper that has passed through the image fixing device 13 is sent to the transport rolls 14, 15, 16 according to the rotation of the discharge rolls 11, 12. Then, when the trailing edge of the sheet passes between the conveyance roll 14 and the conveyance roll 15 through the branch position of the sheet conveyance path toward the conveyance roll 17 side, after the rotation of the conveyance rolls 15 and 16 is temporarily stopped, until then The transport rolls 15 and 16 rotate in the opposite direction. As a result, the sheet is fed into the transport roll 17.

  Thereafter, the sheet is fed again to the transport roll 8 according to the rotation of the transport rolls 17 to 21. Thereafter, an image is formed (transferred and fixed) on the second surface of the sheet in the same procedure as that for forming an image on the first surface.

  The paper on which images are formed on both sides in this way is sent to the discharge roll 26 via the transport rolls 11, 12 and 13 in order. When the paper is turned upside down and discharged, the paper is sent to the transport roll 14 according to the rotation of the transport rolls 11 and 12, and then the paper is sent to the transport roll 13 by the reverse rotation of the transport roll 14. Further, it is fed into the discharge roll 26 as the transport roll 13 rotates.

  FIG. 2 is a front view illustrating a configuration example of the paper discharge device according to the embodiment of the present invention. In this specification, the paper discharge direction (conveyance direction) by the discharge roll 26 is defined as the Y direction, and the direction parallel to the paper conveyance surface and perpendicular to the paper discharge direction Y (depth direction in FIG. 2) is the paper width direction. X is defined. A direction perpendicular to the paper discharge direction Y and the paper width direction X is defined as a paper stacking direction Z. In FIG. 2, the paper discharge direction Y and the paper width direction X are both set in the horizontal direction, and the paper stacking direction Z is set in the vertical direction (vertical direction).

  Further, in this specification, among the four edge portions of the sheet having a rectangular shape in plan view, the edge portion of the sheet disposed facing the downstream side in the sheet discharge direction Y is defined as “the leading edge of the sheet”. The edge portion of the sheet arranged facing the upstream side in the sheet discharge direction Y is defined as “the trailing end of the sheet”. In addition, an edge portion of a sheet disposed in a direction parallel to the sheet conveyance surface and orthogonal to the sheet discharge direction Y is defined as “side edge of sheet”.

  Further, in this specification, a surface on which the paper 29 discharged by the discharge roll 26 is actually stacked on the paper stacking base 28 is defined as a “paper stacking surface”. Therefore, when no sheet 29 is placed on the sheet stacking table 28, the upper surface 28A of the sheet stacking table 28 becomes the sheet stacking surface, and one or more sheets 29 are placed on the sheet stacking table 28. In the loaded state, the upper surface of the uppermost (uppermost) sheet 29 is the sheet stacking surface.

  The height position of the paper stacking surface in the paper stacking direction Z is gradually lowered from the initial position as the number of sheets 29 (stacking height) stacked on the paper stacking base 28 increases. As described above, the mechanism is maintained at a substantially constant position by controlling the driving of a lift drive unit (not shown). Therefore, in the paper stacking direction Z, the step between the discharge roll 26 and the paper stacking surface is also maintained at a substantially constant step.

  The leading edge regulating member 31 regulates the leading edge position of the paper 29 loaded on the paper stacking base 28. Further, the trailing edge regulating member 32 regulates the trailing edge position of the sheets 29 stacked on the sheet stacking base 28. The leading edge regulating member 31 and the trailing edge regulating member 32 are arranged to face each other in order to align the sheet position in the sheet discharge direction Y. The front end restricting member 31 and the rear end restricting member 32 are made of, for example, a flat plate member made of resin.

  The leading edge regulating member 31 has a surface facing the trailing edge regulating member 32 as a reference surface 31A, and aligns the leading edge position of the sheet 29 by abutting the leading edge of the sheet 29 against the reference surface 31A. The rear end regulating member 32 uses the surface 32A facing the front end regulating member 31 as a reference surface, and aligns the rear end position of the paper 29 by abutting the rear end of the paper 29 against the reference surface 32A. It is. Each of the reference surfaces 31A and 32A is disposed perpendicular to the upper surface 28A of the paper stacking base 28. The leading edge regulating member 31 is provided so as to be movable in the paper discharge direction Y by a movable mechanism (not shown), and the trailing edge regulating member 32 is fixed so as not to move in the paper discharge direction Y.

  The position of the leading edge regulating member 31 in the sheet discharge direction Y is adjusted according to the length of the sheet with the position of the trailing edge regulating member 32 as a reference. That is, when the length of the sheet is relatively long, the position of the trailing edge regulating member 32 is adjusted so that the distance from the trailing edge regulating member 32 becomes relatively long accordingly. When the length of the sheet is relatively short, the position of the leading edge regulating member 31 is adjusted so that the distance from the trailing edge regulating member 32 is relatively short. Incidentally, the paper length refers to the paper size in the paper discharge direction Y.

  The paddle member 33 has a plurality of (three in the illustrated example) fin portions 33A on the outer peripheral portion thereof. The fin portion 33A has a high frictional resistance with respect to the paper surface of the paper 29 and is configured using a rubber material such as silicone rubber so as to be elastically deformed. The paddle member 33 rotates in the clockwise direction in the drawing in accordance with the driving of a paddle driving unit (not shown).

  The paddle member 33 is loaded on the sheet stacking surface and has a function of promoting the fall of the sheet by hitting the rear end of the sheet with the fin portion 33A from above by the rotation operation of the paddle itself when the sheet is discharged by the discharge roll 26. By pulling in the sheet with the fin portion 33A, the function of drawing the sheet toward the rear end regulating member 32 is achieved.

  The trailing edge regulating member 32 has an opening 34 for extending the fin portion 33A of the paddle member 33 to a position directly above the sheet stacking base 28 and hitting the trailing edge of the sheet by the fin portion 33A. . The opening 34 is formed in, for example, a quadrangle (rectangular shape), and the lower end portion thereof is disposed at a position lower than the sheet stacking surface. Further, a plurality of paddle members 33 are provided side by side in the paper width direction X.

  In this case, for example, if three paddle members 33 are provided side by side in the paper width direction X, the rear end regulating member 32 has the same number as the number of paddle members 33 (three in this example) as shown in FIG. ) Openings 34 are provided side by side in the paper width direction X. When the paper 29 loaded on the paper stacking base 28 is, for example, the minimum width paper handled by the image forming apparatus 1, at least one opening 34 is arranged within the entire width of the minimum width paper. Yes.

  In addition to the plurality of openings 34, the rear end regulating member 32 shown in FIG. 3 is provided with a plurality of (two in the illustrated example) openings 35 having a smaller diameter. The opening 35 is provided between two openings 34 (intermediate) adjacent in the paper width direction X. The shape of the opening 35 is not limited to a quadrangle, and may be a circle (including an ellipse), a triangle, a pentagon or more polygon, a slit shape, or the like.

  Further, an exhaust duct 36 and an exhaust fan 37 are attached to the rear end regulating member 32 as exhaust means. The exhaust duct 36 is formed in a cylindrical shape having a rectangular cross section, with one opening serving as an air inlet and the other opening serving as an air outlet. One opening (air inlet) of the exhaust duct 36 is abutted against the rear end regulating member 32 on the side opposite to the reference surface 32A so as to communicate with the plurality of openings 34 and 35. The exhaust fan 37 is attached to the other opening (air outlet) of the exhaust duct 36.

  The exhaust duct 36 and the exhaust fan 37 exhaust air from the corners facing the reference surface 32 </ b> A of the rear end regulating member 32 and the sheet stacking surface on the sheet stacking table 28. In this case, the reference surface 32A of the rear end regulating member 32 and the sheet stacking surface on the sheet stacking table 28 define an L-shaped space when viewed from the front of the image forming apparatus 1, as shown in FIG. For this reason, the exhaust duct 36 and the exhaust fan 37 discharge air through this space.

  The exhaust direction by the exhaust duct 36 and the exhaust fan 37 is set to be opposite to the paper discharge direction Y by the discharge roll 26. That is, in FIG. 2, the discharge roll 26 discharges the paper in the right direction, whereas the exhaust duct 36 and the exhaust fan 37 exhaust the air in the corners in the left direction.

  In the paper discharge device 3 configured as described above, when the paper on which image formation on one side or both sides has been completed in the image forming apparatus main body 2 is sent by the transport roll 13, the fed paper is stacked by the discharge roll 26. It is discharged onto the table 28. At this time, the paddle member 33 is controlled by a paper discharge control unit (not shown) so as to always rotate.

  Further, a paper discharge control unit (not shown) controls the exhaust fan 37 to always rotate and drive from the start of the image forming process to the end of the image forming apparatus 1. In this case, the time when the exhaust fan 37 starts to rotate is, for example, the time when the user of the image forming apparatus 1 instructs to start the image forming process on the operation panel or the like, or the paper discharge sensor 27 sets the first sheet. It is set to the time when the tip passage of is detected. Further, the time at which the rotational drive of the exhaust fan 37 is ended is set, for example, at a time when a predetermined time has elapsed after the paper discharge sensor 27 detects the passage of the trailing edge of the final sheet.

  Here, when the paper is discharged by the discharge roll 26, as indicated by the wavy line or the two-dot chain line in FIG. 2, the front end of the paper falls first due to its own weight and touches (lands) the paper stacking surface. The trailing edge of the paper falls toward the paper stacking surface. At that time, if the sheet is discharged by the discharge roll 26 with the exhaust fan 37 stopped, the sheet is falling in the corner space facing the reference surface 32A of the rear end regulating member 32 and the sheet stacking surface. An air pocket is generated in the lower portion 38 of the paper. This air pocket acts to suppress the fall of the paper. For this reason, the falling speed of the paper is affected by air pockets and varies depending on the paper quality, thickness, basis weight, curl state, and the like of the paper.

  On the other hand, when the sheet is discharged by the discharge roll 26 in a state where the exhaust fan 37 is driven to rotate, the rear end restriction is started from the corner facing the reference surface 32A of the rear end restriction member 32 and the sheet stacking surface. Air is exhausted by the exhaust fan 37 through the openings 34 and 35 of the member 32 and the exhaust duct 36. At this time, the air exhausted by the exhaust fan 37 is interposed between the sheet that is falling in the sheet stacking direction Z and the sheet stacking surface (the upper surface 28A of the sheet stacking table 28 or the upper surface of the sheet 29 stacked at the uppermost position). Air. For this reason, a negative pressure space is formed in the portion 38 on the lower surface side of the falling paper instead of the air reservoir, and the trailing edge of the paper drops toward the paper stacking surface as it is drawn into the negative pressure. Come on. Therefore, as compared with the case where the exhaust fan 37 is stopped as described above, the falling speed of the paper is increased, and variations in the falling speed due to the paper quality, thickness, basis weight, curl state, and the like are reduced. .

  In the above embodiment, the exhaust direction of the exhaust means (exhaust duct 36, exhaust fan 37) is set to be opposite to the paper discharge direction Y by the discharge roll 26. However, the present invention is not limited to this, and the exhaust The exhaust direction of the means may be set in the paper width direction X. In that case, for example, one opening (a suction port for air) of the duct faces the space of the corner with respect to the corner facing the reference surface 32A of the rear end regulating member 32 and the sheet stacking surface. May be provided in one or both of the paper width direction X.

<Application example>
The present invention is applied to an image forming apparatus such as a printer, a copier, a facsimile machine, and a multi-function machine, and a paper discharge apparatus that is connected to the image forming apparatus or another paper processing apparatus.

1 is a schematic diagram illustrating a configuration example of an image forming apparatus to which the present invention is applied. 1 is a front view illustrating a configuration example of a paper discharge device according to an embodiment of the present invention. It is a figure which shows the structure of a rear-end control member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 3 ... Paper discharge apparatus, 26 ... Discharge roll, 28 ... Paper stacking board, 29 ... Paper, 31 ... Front end regulating member, 31A, 32A ... Reference plane, 32 ... Rear end regulating member, 33 ... Paddle Member, 33A ... fin portion, 34, 35 ... opening, 36 ... exhaust duct, 37 ... exhaust fan

Claims (1)

A discharge member for discharging the paper;
A paper stacking unit on which paper discharged by the discharge member is stacked;
A paddle member having a rotating fin and promoting the fall of the sheet by hitting the trailing edge of the sheet discharged by the discharging member from above with the rotating fin;
A drive unit for driving the paddle member;
A rear end regulating member that has an opening through which the fin passes and regulates a rear end position of the paper stacked on the paper stacking unit;
Exhaust means for exhausting air from the corner facing the reference surface of the trailing edge regulating member and the paper stacking surface of the paper stacking unit through the opening in the direction opposite to the paper discharge direction by the discharge member. A paper discharge device.

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