US20140151954A1 - Sheet feeding device and image forming apparatus - Google Patents

Sheet feeding device and image forming apparatus Download PDF

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Publication number
US20140151954A1
US20140151954A1 US14/084,900 US201314084900A US2014151954A1 US 20140151954 A1 US20140151954 A1 US 20140151954A1 US 201314084900 A US201314084900 A US 201314084900A US 2014151954 A1 US2014151954 A1 US 2014151954A1
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United States
Prior art keywords
sheet
sheet feeding
separating
force
movable wall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US14/084,900
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English (en)
Inventor
Motohiro Furusawa
Yasuhito Fujinuma
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Canon Inc
Original Assignee
Canon Inc
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Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Assigned to CANON KABUSHIKI KAISHA reassignment CANON KABUSHIKI KAISHA ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FUJINUMA, YASUHITO, FURUSAWA, MOTOHIRO
Publication of US20140151954A1 publication Critical patent/US20140151954A1/en
Abandoned legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H1/00—Supports or magazines for piles from which articles are to be separated
    • B65H1/08—Supports or magazines for piles from which articles are to be separated with means for advancing the articles to present the articles to the separating device
    • B65H1/12—Supports or magazines for piles from which articles are to be separated with means for advancing the articles to present the articles to the separating device comprising spring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H3/00—Separating articles from piles
    • B65H3/02—Separating articles from piles using friction forces between articles and separator
    • B65H3/06—Rollers or like rotary separators
    • B65H3/0684—Rollers or like rotary separators on moving support, e.g. pivoting, for bringing the roller or like rotary separator into contact with the pile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H3/00—Separating articles from piles
    • B65H3/46—Supplementary devices or measures to assist separation or prevent double feed
    • B65H3/52—Friction retainers acting on under or rear side of article being separated
    • B65H3/5207—Non-driven retainers, e.g. movable retainers being moved by the motion of the article
    • B65H3/5215—Non-driven retainers, e.g. movable retainers being moved by the motion of the article the retainers positioned under articles separated from the top of the pile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H3/00—Separating articles from piles
    • B65H3/46—Supplementary devices or measures to assist separation or prevent double feed
    • B65H3/56—Elements, e.g. scrapers, fingers, needles, brushes, acting on separated article or on edge of the pile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H7/00—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2220/00—Function indicators
    • B65H2220/01—Function indicators indicating an entity as a function of which control, adjustment or change is performed, i.e. input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2405/00—Parts for holding the handled material
    • B65H2405/10—Cassettes, holders, bins, decks, trays, supports or magazines for sheets stacked substantially horizontally
    • B65H2405/11—Parts and details thereof
    • B65H2405/113—Front, i.e. portion adjacent to the feeding / delivering side
    • B65H2405/1134—Front, i.e. portion adjacent to the feeding / delivering side movable, e.g. pivotable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2405/00—Parts for holding the handled material
    • B65H2405/10—Cassettes, holders, bins, decks, trays, supports or magazines for sheets stacked substantially horizontally
    • B65H2405/11—Parts and details thereof
    • B65H2405/113—Front, i.e. portion adjacent to the feeding / delivering side
    • B65H2405/1136—Front, i.e. portion adjacent to the feeding / delivering side inclined, i.e. forming an angle different from 90 with the bottom
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2511/00—Dimensions; Position; Numbers; Identification; Occurrences
    • B65H2511/20—Location in space
    • B65H2511/21—Angle
    • B65H2511/214—Inclination
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2515/00—Physical entities not provided for in groups B65H2511/00 or B65H2513/00
    • B65H2515/30—Forces; Stresses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2515/00—Physical entities not provided for in groups B65H2511/00 or B65H2513/00
    • B65H2515/81—Rigidity; Stiffness; Elasticity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00—Handled material; Storage means
    • B65H2701/10—Handled articles or webs
    • B65H2701/17—Nature of material
    • B65H2701/171—Physical features of handled article or web

Definitions

  • the present invention relates to a sheet feeding device and an image forming apparatus, particularly to a sheet feeding device and an image forming apparatus, in which a sheet is separated one by one using a separating slope.
  • an image forming apparatus such as a copying machine, a printer, and a facsimile machine, includes a sheet feeding device that feeds a sheet to an image forming portion, and a separating portion is provided in the sheet feeding device in order to separate the sheet one by one.
  • a separating portion including a slope separation system (see U.S. Pat. No. 5,622,364).
  • a separating slope is provided on a leading end side of a tray on which the sheet is stacked, and the sheet fed by a feeding roller is pressed against the separating slope to separate the sheet one by one.
  • an angle of the separating slope is decreased such that the uppermost sheet can be conveyed by the small force while separated, namely, such that the force necessary to separate and convey the uppermost sheet is decreased.
  • a force which presses the uppermost sheet such that the next sheet is not fed due to a curvature of the uppermost sheet by the slope, is smaller than a frictional force between the sheets in the case that thin paper having the small stiffness is fed.
  • a ratio that indicates generation of multi feeding is increased because a lower sheet is conveyed together with the uppermost sheet. That is, separating performance degrades for the sheet having the small stiffness when the force necessary to separate and convey the sheet having the large stiffness is decreased, and the force necessary to separate and convey the sheet having the large stiffness increases when the sheet having the small stiffness is securely separated.
  • a sheet feeding device includes: a sheet stacking portion on which a sheet is stacked; a sheet feeding portion which feeds the sheet stacked on the sheet stacking portion; a separating portion which includes a separating slope, the separating slope separating the sheet one by one by abutting on the sheet fed by the sheet feeding portion, the separating slope being movable along a sheet feeding direction; a force applying portion which applies a force to the separating portion in a direction opposite to the sheet feeding direction; and a support portion which supports the separating portion such that the separating portion is movable, and such that the separating portion is sloped in connection with the movement when abutting on the sheet fed by the sheet feeding portion and moving a downstream side in the sheet feeding direction against an applying force of the force applying portion.
  • FIG. 1 is a view illustrating a configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention
  • FIG. 2 is a view illustrating a configuration of a separating portion provided in the sheet feeding device
  • FIGS. 3A and 3B are views illustrating movement of a movable wall constituting the separating portion
  • FIGS. 4A and 4B are schematic diagrams illustrating a force applied to the movable wall
  • FIG. 5 is a view illustrating a relationship between an acting force of a force applying spring, which applies a force to the movable wall, and a conveying force according to a type of sheet;
  • FIG. 6 is a view illustrating a conveying force of a feeding roller
  • FIGS. 7A , 7 B, and 7 C are views illustrating a sheet feeding operation of the sheet feeding device
  • FIG. 8 is a view illustrating a relationship between a slope angle of the movable wall and the conveying force
  • FIG. 9 is a first view illustrating a configuration of a separating portion provided in a sheet feeding device according to a second embodiment of the present invention.
  • FIG. 10 is a second view illustrating the configuration of the separating portion.
  • FIGS. 11A , 11 B, and 11 C are views illustrating a sheet feeding operation of the sheet feeding device.
  • FIG. 1 is a view illustrating a configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention.
  • the numeral 50 designates a laser beam printer and the numeral 50 A designates a laser beam printer body (hereinafter referred to as a printer body).
  • the printer body 50 A includes an image forming portion 50 B.
  • a sheet feeding device 1 that feeds a sheet S, such as a recording sheet, which is stacked on and stored in a tray 3 , to the image forming portion 50 B is provided in a lower portion of the printer body 50 A.
  • the image forming portion 50 B includes a process cartridge 21 , and the process cartridge 21 includes a photosensitive drum 21 a , a charging device (not illustrated), a development sleeve (not illustrated), and a cleaner (not illustrated).
  • the image forming portion 50 B also includes a laser scanner 20 that exposes a surface of the photosensitive drum 21 a to form an electrostatic latent image on the photosensitive drum 21 a .
  • the printer body 50 A includes a transfer roller 21 b and a fixing portion 22 .
  • the transfer roller 21 b abuts on the photosensitive drum 21 a , and constitutes a transfer portion together with the photosensitive drum 21 a .
  • the fixing portion 22 fixes a toner image, which is transferred by the transfer portion, onto a sheet S.
  • the sheet feeding device 1 includes a feeding roller 5 and a separating portion 30 .
  • the feeding roller 5 that is of the sheet feeding portion feeds the sheet S, which is stacked on the tray 3 that is of the sheet stacking portion on which the sheet S is stacked, from the uppermost side.
  • the separating portion 30 separates the sheet one by one.
  • the feeding roller 5 is turnably supported by a turning end part of a turning arm 17 .
  • the turning arm 17 is supported while being vertically turnable about a turning shaft 4 that is retained by a stay (not illustrated) fixed to a sheet feeding device body (not illustrated).
  • the feeding roller 5 abuts on an upper surface of an uppermost sheet Sa by the turn of the turning arm 17 .
  • the sheet S is pushed into the tray 3 from a lateral side (a right side of the printer body in FIG. 1 ) of the printer body 50 A.
  • the photosensitive drum 21 a rotates clockwise, the surface of the photosensitive drum 21 a is charged by the charging device (not illustrated), and the laser scanner 20 emits a laser beam to the photosensitive drum 21 a based on image information. Therefore, the electrostatic latent image is formed on the photosensitive drum. Then the electrostatic latent image is developed using toner, and visualized as the toner image.
  • the feeding roller 5 of the sheet feeding device 1 rotates while abutting on the uppermost sheet Sa on the tray 3 , thereby feeding the uppermost sheet Sa.
  • the uppermost sheet Sa fed by the feeding roller 5 is conveyed by the separating portion 30 while separated one by one, the uppermost sheet Sa is conveyed to the transfer portion by a conveying roller pair 23 , and the image on the photosensitive drum 21 a is transferred to the uppermost sheet Sa by the transfer roller 21 b .
  • the uppermost sheet Sa to which the toner image is transferred is conveyed to the fixing portion 22 , and unfixed toner image is heated and pressurized by passing between a heating roller 22 a and a pressure roller 22 b , thereby fixing the toner image to the surface of the sheet.
  • a sheet Sa, to which the toner image is already fixed, is discharged on a discharge tray 27 by a discharge roller 26 while the image surface of the sheet Sa is oriented downward.
  • FIG. 2 is a view illustrating a configuration of the separating portion 30 .
  • the separating portion 30 includes a movable wall 6 , support members 31 and 32 that movably support the movable wall 6 , a fixed wall 33 , a force applying spring 10 that is of a compression spring provided between the movable wall 6 and the fixed wall 33 , and a cam 7 .
  • a sheet abutting surface 6 b that is of the separating slope is provided on the feeding roller side of the movable wall 6 .
  • the sheet abutting surface 6 b includes a slope.
  • the sheet S fed by the feeding roller 5 is pressed against the slope, and the slope is inclined with respect to a vertical direction in which the sheet is conveyed while separated one by one.
  • Two bosses (projections) 6 a are projected in each of side surfaces in a width direction, which is orthogonal to the sheet feeding direction, of the movable wall 6 that is of the separating portion movable along the sheet feeding direction.
  • the two bosses 6 a are disposed along the sheet feeding direction in order to determine a moving direction of the movable wall 6 or an attitude of the movable wall 6 during the movement.
  • First and second boss grooves 9 a and 9 b in which the bosses 6 a of the movable wall 6 are movable, are formed in each of the support members 31 and 32 that are of the support portion movably supporting the movable wall 6 .
  • the support members 31 and 32 movably support the movable wall 6 with the first and second boss grooves 9 a and 9 b interposed therebetween.
  • the first boss groove 9 a located on the side of the sheet abutting surface 6 b of the movable wall 6 is formed in substantially parallel with a sheet stacking surface 3 a of the tray 3 in FIG. 1 .
  • the second boss groove 9 b located on a downstream side of the boss groove 9 a in the sheet feeding direction is formed sloped such that the downstream side of the second boss groove 9 b in the sheet feeding direction is lowered.
  • the movable wall 6 is usually maintained in a standby state in which the bosses 6 a of the movable wall 6 abut on upstream ends of the first and second boss grooves 9 a and 9 b in the sheet feeding direction by the force applying spring 10 provided between the movable wall 6 and the fixed wall 33 .
  • the sheet abuts on the movable wall 6 in setting the sheet on the tray, whereby a spring force of the force applying spring 10 that is of the force applying portion applying the force to the movable wall 6 in the direction opposite to the sheet feeding direction is set to magnitude at which the movable wall 6 does not move even if an external force Fx is applied. Therefore, the movable wall 6 is maintained in the standby state in FIG. 3A , when the external force Fx is not applied or when the external force Fx is smaller than a force applying spring acting force Fsp obtained by the applying force of the force applying spring 10 .
  • the fed sheet moves the movable wall 6 against the applying force of the force applying spring 10 , and the movable wall 6 moves onto the downstream side in the sheet feeding direction from the standby position in FIG. 3A to the state in FIG. 3B , whereby the angle (a slope angle) between the sheet abutting surface 6 b and the sheet stacking surface 3 a changes from ⁇ 1 to ⁇ 2 . That is, the acute angle between the sheet abutting surface 6 b and the sheet stacking surface 3 a decreases ( ⁇ 1 ⁇ 2 ).
  • the cam 7 regulates the movement of the movable wall 6 on the downstream side in the sheet feeding direction, and the cam 7 abuts on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 to regulate the movement of the movable wall 6 until the feeding roller 5 starts to feed the sheet.
  • a signal is input to a solenoid (not illustrated) from an electric board (not illustrated) to attract the solenoid, and a driving force is transmitted from a driving train (not illustrated) to rotate the cam 7 .
  • the rotation of the cam 7 that is of the regulation portion releases the regulation of the cam 7 . Therefore, the movable wall 6 can move onto the downstream side in the sheet feeding direction when the sheet fed by the feeding roller 5 abuts on the movable wall 6 .
  • FIG. 4 is a schematic diagram illustrating forces acting onto the movable wall 6
  • FIG. 4A is a schematic diagram illustrating the forces acting onto the movable wall 6 in the first embodiment
  • FIG. 4B is a reference drawing for comparison.
  • a movable wall 206 turns with a turning center 206 a as a supporting point.
  • the turning center 206 a is provided below the sheet stacking surface 3 a .
  • the turning center of the movable wall 6 can be located downward far away from the sheet stacking surface 3 a compared with the case in FIG. 4B .
  • the difference among the force applying spring acting forces Fsp 1 , Fsp 2 , and Fsp 3 of the force applying spring 10 can be reduced irrespective of the position in the height direction of the sheet abutting surface 6 b .
  • FIG. 5 is a view illustrating a relationship between the force applying spring acting force Fsp of the force applying spring 10 and the conveying force of the sheet S according to a type of sheet.
  • a vertical axis indicates conveying forces Fz of typical sheet S in a situation in which the movable wall 6 is fixed to the position in the standby state, namely, the forces, which are generated by the difference in stiffness of the sheet and are necessary to convey the sheet S with the leading end bent.
  • the vertical axis also indicates a conveying force Fr obtained from the feeding roller 5 and the force applying spring acting force Fsp of the force applying spring 10 .
  • the conveying force Fr of the feeding roller 5 will be described with reference to FIG. 6 .
  • the conveying force Fr of the feeding roller 5 is obtained by multiplying a normal reaction N, which is generated by the rotation and bite of the feeding roller 5 , by a friction factor between the feeding roller 5 and the sheet S.
  • the normal reaction N is determined by conditions such as a distance h between the turning shaft 4 and the uppermost sheet Sa and a distance L between the turning shaft 4 and the feeding roller 5 .
  • the distance h changes according to the stacking level of the sheet S.
  • the friction factor between the feeding roller 5 and the sheet S is determined by conditions such as a material for the feeding roller 5 and the type of the sheet S.
  • the surface of the sheet abutting surface 6 b is set such that the conveying forces Fz for the thin paper (basis weight of 60 g/m 2 ) and the plain paper (basis weight of 80 g/m 2 ) are less than or equal to about 3 N, and such that the conveying forces Fz for the thick paper (basis weight of 160 g/m 2 ) and an envelope are greater than or equal to about 10 N.
  • the conveying force Fr obtained from the feeding roller 5 is substantially kept constant even if the distance h changes.
  • the force applying spring acting force Fsp of the force applying spring 10 is set so as to be greater than the conveying forces Fz for the plain paper and the thin paper and so as to be less than the conveying forces Fz for the thick paper and the envelope and the conveying force Fr of the feeding roller 5 . Therefore, in the first embodiment, the force applying spring acting force Fsp of the force applying spring 10 is set to 5 N in order to satisfy the above conditions.
  • FIG. 7A illustrates the state when a user sets the sheet S into the tray 3 .
  • the cam 7 is located at a home position to abut on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 , whereby the movement of the movable wall 6 is regulated.
  • the movable wall 6 does not move even if the sheet S abuts on the movable wall 6 . Therefore, the user can easily set the sheet S by abutting the leading end of the sheet S on the movable wall 6 . That is, a good setting property can be provided in setting the sheet S.
  • FIG. 7B illustrates the state in which the thin paper having the basis weight of 60 g/m 2 is fed.
  • the signal is input to the solenoid from the electric board (not illustrated) to start the rotation of the cam 7 , the cam 7 separates from surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 , and the movable wall 6 is put into the movable state.
  • the uppermost sheet Sa When the uppermost sheet Sa is further pressed against the sheet abutting surface 6 b of the movable wall 6 while the movable wall 6 does not move, the uppermost sheet Sa is fed while only the leading end of the uppermost sheet Sa is bent. Therefore, the uppermost sheet Sa separates from the lower sheet, and the uppermost sheet Sa is conveyed to the conveying roller pair 23 while guided by the sheet abutting surface 6 b of the movable wall 6 .
  • the conveying force Fr of the feeding roller 5 is insufficient because the conveying force Fr acts on the lower sheet via the frictional force between the sheets. Even if the leading end of the lower sheet abuts on the sheet abutting surface 6 b of the movable wall 6 , the leading end is not bent and the lower sheet is not conveyed. Therefore, the lower sheet is not fed together with the uppermost sheet Sa, and the multi feeding is not generated. After the uppermost sheet Sa is conveyed to the conveying roller pair 23 , the cam 7 again reaches the home position at which the cam 7 abuts on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 , and the cam 7 stops the rotation.
  • FIG. 7C illustrates the state in which the thick paper having the basis weight of 160 g/m 2 is fed.
  • the uppermost sheet Sa is conveyed by the rotation of the feeding roller 5 , and pressed against the sheet abutting surface 6 b of the movable wall 6 to which the force is applied by the force applying spring 10 .
  • the conveying force Fr of the feeding roller 5 is applied to the movable wall 6
  • the conveying force Fr has predetermined stiffness or more because the sheet is the thick paper. Therefore, the conveying force Fr is larger than the force applying spring acting force Fsp of the force applying spring 10 , which is necessary to convey the uppermost sheet Sa with the leading end bent.
  • the uppermost sheet Sa presses the movable wall 6 without bending the leading end, and the movable wall 6 moves along the first and second boss grooves 9 a and 9 b .
  • the movement of the movable wall 6 decreases the slope angle ⁇ formed between the sheet abutting surface 6 b and the sheet stacking surface 3 a.
  • FIG. 8 illustrates a relationship between the conveying force Fz and the slope angle ⁇ in feeding the thick paper having the basis weight of 160 g/m 2 .
  • the conveying force Fz necessary to convey the sheet S with the leading end bent decreases with decreasing slope angle ⁇ .
  • the slope angle ⁇ reaches about 72°, the movement of the movable wall 6 is stopped by the applying force of the force applying spring 10 to bend the leading end of the uppermost sheet Sa. Then, the uppermost sheet Sa is conveyed to the conveying roller pair 23 while guided by the sheet abutting surface 6 b and the guide.
  • the conveying force Fr of the feeding roller 5 is insufficient because the conveying force Fr acts on the lower sheet via the frictional force between the sheets, but the leading end of the lower sheet cannot be bent and conveyed even if the leading end of the lower sheet abuts on the sheet abutting surface 6 b . Therefore, the lower sheet is not fed together with the uppermost sheet Sa, and the multi feeding is not generated.
  • the cam 7 again reaches the home position at which the cam 7 abuts on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 , and the cam 7 stops the rotation.
  • the movable wall 6 is movably provided, and the movable wall 6 is sloped by the movement. Therefore, a wide variety of sheets from the thin paper that is of the sheet having weak conveying force to the thick paper or envelope that is of the sheet having the strong conveying force can surely be separated and fed.
  • the turning center of the movable wall 6 is largely separated below the sheet stacking surface 3 a , so that the change in force applying spring acting force Fsp of the force applying spring 10 acting on the uppermost sheet Sa can be decreased even if the stacking level of the sheet S changes. As a result, the fluctuation of the condition that the movable wall 6 moves according to the stacking level of the sheet S can be decreased and the stable sheet separating and feeding performance can be exerted.
  • the movable wall 6 having the sheet abutting surface 6 b is sloped when the sheet fed by the feeding roller 5 abuts on the movable wall 6 to move the movable wall 6 . Therefore, the sheet can stably be separated and fed irrespective of the stiffness of the sheet.
  • the good setting property can be provided by providing the cam 7 when the user sets the sheet into the tray.
  • the stable sheet separating and feeding performance can also be exerted even in the case that the cam 7 is not provided.
  • FIGS. 9 and 10 are views illustrating a configuration of a sheet feeding device according to a second embodiment.
  • the component identical or equivalent to that in FIGS. 2 and 3 is designated by the identical numeral.
  • the first boss groove 9 a is formed so as to be inclined obliquely upward with increasing distance from the feeding roller 5 .
  • the angle formed between the sheet abutting surface 6 b of the movable wall 6 and the sheet stacking surface 3 a changes when the movable wall 6 moves, and the upper end of the sheet abutting surface 6 b is always higher than a height H 6 at the position in the standby state irrespective of a movement amount of the movable wall 6 .
  • FIG. 11A illustrates the state in which the user sets the sheet S into the tray 3 in the second embodiment. At this point, the cam 7 abuts on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 .
  • FIG. 11B illustrates the state in which the thin paper having the basis weight of 60 g/m 2 is fed. At this point, the cam 7 separates from the movable wall 6 , and the movable wall 6 is in the movable state.
  • the movable wall 6 When the feeding roller 5 starts the rotation to feed the uppermost sheet Sa, the uppermost sheet Sa is pressed against the sheet abutting surface 6 b of the movable wall 6 to which the applying force is applied by the force applying spring 10 . At this point, the movable wall 6 is in the movable state, and the conveying force Fr of the feeding roller 5 is applied to the movable wall 6 via the uppermost sheet Sa. However, the conveying force Fr necessary to convey the sheet S with the leading end bent is smaller than the force applying spring acting force Fsp of the force applying spring 10 because the uppermost sheet Sa is the thin paper. Therefore, the movable wall 6 does not move.
  • the uppermost sheet Sa When the uppermost sheet Sa is further pressed against the sheet abutting surface 6 b of the movable wall 6 while the movable wall 6 does not move, the uppermost sheet Sa is fed while only the leading end of the uppermost sheet Sa is bent, thereby separating the uppermost sheet Sa from the lower sheet.
  • the separated uppermost sheet Sa is conveyed to the conveying roller pair 23 while guided by the sheet abutting surface 6 b of the movable wall 6 .
  • the conveying force Fr of the feeding roller 5 is small because the conveying force Fr acts on the lower sheet via the frictional force between the sheets. Even if the leading end of the lower sheet abuts on the sheet abutting surface 6 b of the movable wall 6 , the leading end is not bent and the lower sheet is not conveyed. Therefore, the lower sheet is not fed together with the uppermost sheet Sa, and the multi feeding is not generated. After the uppermost sheet Sa is conveyed to the conveying roller pair 23 , the cam 7 again reaches the home position at which the cam 7 abuts on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 , and the cam 7 stops the rotation.
  • FIG. 11C illustrates the state in which the thick paper having the basis weight of 160 g/m 2 is fed.
  • the cam 7 separates from the movable wall 6 , and the movable wall 6 is in the movable state.
  • the feeding roller 5 starts the rotation to feed the uppermost sheet Sa
  • the uppermost sheet Sa is pressed against the sheet abutting surface 6 b of the movable wall 6 to which the force is applied by the force applying spring 10 .
  • the movable wall 6 is in the movable state, and the conveying force Fr of the feeding roller 5 is applied to the movable wall 6 .
  • the conveying force Fr necessary to convey the uppermost sheet Sa with the leading end bent is larger than the force applying spring acting force Fsp of the force applying spring 10 because the uppermost sheet Sa is the thick paper. Therefore, the movable wall 6 moves along the first and second boss grooves 9 a and 9 b.
  • the slope angle ⁇ formed between the sheet abutting surface 6 b and the sheet stacking surface 3 a changes according to the movement amount.
  • the relationship between the slope angle ⁇ and the conveying force Fz for the thick paper having the basis weight of about 160 g/m 2 is illustrated in FIG. 8 described above, and the second embodiment conforms to the relationship in FIG. 8 .
  • the leading end of the uppermost sheet Sa is bent when the slope angle ⁇ reaches about 72°, and then the uppermost sheet Sa is conveyed to the conveying roller pair 23 while guided by the sheet abutting surface 6 b and a guide on the downstream side.
  • the conveying force Fr of the feeding roller 5 is small because the conveying force Fr acts on the lower sheet via the frictional force between the sheets, but the leading end of the lower sheet cannot be bent and conveyed even if the leading end of the lower sheet abuts on the sheet abutting surface 6 b . Therefore, the lower sheet is not fed together with the uppermost sheet Sa, and the multi feeding is not generated.
  • the cam 7 again reaches the home position at which the cam 7 abuts on the surface on the opposite side to the sheet abutting surface 6 b of the movable wall 6 , and the cam 7 stops the rotation.
  • the first boss groove 9 a is formed in substantially parallel to the sheet stacking surface 3 a , when the movable wall 6 is sloped by the movement, the level at the upper end of the sheet abutting surface 6 b of the movable wall 6 is lowered compared with the height H 6 at the position in the standby state as the movable wall 6 moves as illustrated in FIG. 7 .
  • the first boss groove 9 a is formed so as to be inclined obliquely upward with increasing distance from the feeding roller 5 .
  • the level at the upper end of the sheet abutting surface 6 b of the movable wall 6 is not lower than the height H 6 at the position in the pre-slope standby state.
  • the leading end of the uppermost sheet Sa can surely be guided to a given level by the sheet abutting surface 6 b of the movable wall 6 irrespective of the movement amount of the movable wall 6 , and the sheet can be fed without generating a conveying failure in a gap with the guide on the downstream side or a step.
  • the first boss groove 9 a is formed so as to be inclined obliquely upward with increasing distance from the feeding roller 5 . Therefore, while the performance of stably separating and feeding the sheet with the sheet pressed against the sheet abutting surface 6 b of the movable wall 6 is maintained, the sheet can surely be fed even if the movable wall 6 moves.
  • the upper end of the sheet abutting surface 6 b is always the height H 6 at the position in the standby state irrespective of a movement amount of the movable wall 6 .
  • the second embodiment is not limited to this, and depending on a shape of the boss groove 9 a , the upper end of the sheet abutting surface 6 b may be higher than the height H 6 at the position in the standby state as the movable wall 6 moves. Even in this case, the leading end of the uppermost sheet Sa can surely be guided to the given level or more by the sheet abutting surface 6 b of the movable wall 6 even if the movable wall 6 moves.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Sheets, Magazines, And Separation Thereof (AREA)
US14/084,900 2012-11-30 2013-11-20 Sheet feeding device and image forming apparatus Abandoned US20140151954A1 (en)

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JP2012263766A JP6066695B2 (ja) 2012-11-30 2012-11-30 シート給送装置及び画像形成装置
JP2012-263766 2012-11-30

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US20150232292A1 (en) * 2014-02-19 2015-08-20 Canon Kabushiki Kaisha Feeding apparatus and printing apparatus
US20150298924A1 (en) * 2014-04-22 2015-10-22 Canon Kabushiki Kaisha Sheet feeding device and image forming apparatus
CN106032215A (zh) * 2014-11-14 2016-10-19 株式会社小矢部精机 片材分离辅助装置
US9725260B2 (en) 2014-10-29 2017-08-08 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US9975717B2 (en) 2016-01-28 2018-05-22 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US20180339873A1 (en) * 2017-05-24 2018-11-29 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US10189674B2 (en) 2016-04-21 2019-01-29 Canon Kabushiki Kaisha Image forming apparatus
US10214374B2 (en) * 2013-12-12 2019-02-26 Canon Denshi Kabushiki Kaisha Sheet feeder, image reading apparatus, and image forming apparatus
US10294068B2 (en) 2016-04-21 2019-05-21 Canon Kabushiki Kaisha Image forming apparatus
US10394178B2 (en) 2017-02-21 2019-08-27 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US11192737B2 (en) * 2019-06-18 2021-12-07 Lexmark International, Inc. Adjustable compliance of separation strips in a media dam

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JP6855229B2 (ja) * 2016-12-14 2021-04-07 キヤノン株式会社 シート支持装置及び画像形成装置
CN110723569B (zh) * 2019-10-15 2021-10-15 朱笑笑 一种喷墨打印机用纸张填充装置
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US10214374B2 (en) * 2013-12-12 2019-02-26 Canon Denshi Kabushiki Kaisha Sheet feeder, image reading apparatus, and image forming apparatus
US9573779B2 (en) * 2014-02-19 2017-02-21 Canon Kabushiki Kaisha Feeding apparatus and printing apparatus
US20150232292A1 (en) * 2014-02-19 2015-08-20 Canon Kabushiki Kaisha Feeding apparatus and printing apparatus
US20150298924A1 (en) * 2014-04-22 2015-10-22 Canon Kabushiki Kaisha Sheet feeding device and image forming apparatus
US9725260B2 (en) 2014-10-29 2017-08-08 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
CN106032215A (zh) * 2014-11-14 2016-10-19 株式会社小矢部精机 片材分离辅助装置
US9975717B2 (en) 2016-01-28 2018-05-22 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US10486927B2 (en) 2016-01-28 2019-11-26 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US10294068B2 (en) 2016-04-21 2019-05-21 Canon Kabushiki Kaisha Image forming apparatus
US10189674B2 (en) 2016-04-21 2019-01-29 Canon Kabushiki Kaisha Image forming apparatus
US10394178B2 (en) 2017-02-21 2019-08-27 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
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Also Published As

Publication number Publication date
JP6066695B2 (ja) 2017-01-25
JP2014108859A (ja) 2014-06-12
CN103848237A (zh) 2014-06-11
CN103848237B (zh) 2016-08-24

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