1. An image recording apparatus comprising:
a housing;
a medium supply cassette open upward which accommodates a stack of recording media each in the form of a sheet, and is inserted into and removed from the housing substantially horizontally in a cassette movement direction, the medium supply cassette including:
a substantially horizontal bottom plate; and
a slant separator plate extending obliquely upward from an edge of the bottom plate;
a medium pickup device which includes a medium pickup roller which gives a feeding force in a first direction to a topmost one of the stack of the recording media, and cooperates with the slant separator plate to separate the topmost recording medium from the rest of the recording media to feed in the separated recording medium;
a U-shaped guide which changes a feeding direction of the recording medium as fed in by the medium pickup device, from the first direction to a second direction opposite to the first direction;
an image recording portion which records an image on the recording medium as has been passed through the U-shaped guide; and
a restricting member which defines a part of a feed path along which the recording medium is fed, which part extends between the medium pickup roller and the U-shaped guide,
wherein the restricting member is configured to contact at least a part of the stack of recording media which ascends upward along the slant separator plate by continuing to move, by inertia, in a cassette insertion direction in which the medium supply cassette is inserted, in order to restrict the continuing movement of the at least a part of the stack.
2. The image recording apparatus according to claim 1, wherein the restricting member is an elastic member at least a lower portion of which is located in a path of movement of the slant separator plate of the medium supply cassette when the medium supply cassette is inserted into the housing such that each time the medium supply cassette is inserted into the housing, the restricting member is pushed away by the slant separator plate and restores to an original position after passage of the slant separator plate.
3. The image recording apparatus according to claim 1, wherein the restricting member and the medium pickup roller are arranged at different positions in a lateral direction substantially perpendicular to the cassette movement direction, in plan view.
4. The image recording apparatus according to claim 3, wherein the restricting member is disposed on each of opposite sides of the medium pickup roller in the lateral direction, at least one on each side.
5. The image recording apparatus according to claim 1, wherein the restricting member has an antistatic property.
6. The image recording apparatus according to claim 1, wherein the restricting member includes an elastic film curved in a U-like shape including a curved portion which is convex downward and contacts the at least a part of the stack of recording media.
7. The image recording apparatus according to claim 6, wherein an inner surface of each of two upper end portions of the film that are opposed to each other is fixed to a stationary holding member with an adhesive, and the image recording apparatus further comprises a deformation restrictor which restricts deformation of two portions which are adjacent to the respective two upper end portions of the film and deform in the cassette movement direction when the medium supply cassette is inserted or removed.
8. The image recording apparatus according to claim 7, wherein the deformation restrictor includes a deformation restricting sheet which has two through-holes through which the two upper end portions of the film to be fixed to the holding member are respectively passed, and inner surfaces of the respective through-holes contact the two adjacent portions of the film, respectively, thereby restricting deformation of the adjacent portions.
9. The image recording apparatus according to claim 8, wherein the holding member is a beam supported by the housing and extending in a lateral direction substantially perpendicular to the cassette movement direction, in plan view.
10. The image recording apparatus according to claim 1, wherein the restricting member includes a contact member which contacts the at least a part of the recording media, and a spring member whose lower end is connected to the contact member and whose upper end is connected to a stationary holding member.
11. The image recording apparatus according to claim 10, wherein the contact member is a contact roller which rotates around an axis substantially perpendicular to the cassette movement direction, in plan view.
12. The image recording apparatus according to claim 1, wherein the restricting member includes a film curved in a U-like shape including a bottom portion, and an elastic member which is disposed inside the film and contacts an internal surface of at least the bottom portion of the film, the at least a part of the stack of the recording media at an external surface of the bottom portion while the elastic member giving an elastic deformation resistance to the film.
13. The image recording apparatus according to claim 1, further comprising a pickup arm pivotable around a first axis substantially perpendicular to the cassette movement direction, the pickup arm rotatably holding at a free end thereof the medium pickup roller, and wherein the restricting member includes a movable restricting member which is mechanically coupled, and moved, with the pickup arm.
14. The image recording apparatus according to claim 13, wherein the movable restricting member is a pivotable restricting member disposed to be pivotable around a second axis which is parallel to the first axis and extends at a position remote from the first axis, the pivotable restricting member being engaged with the pickup arm at a position remote from the second axis such that the pivotable restricting member is pivoted in accordance with pivoting of the pickup arm.
15. The image recording apparatus according to claim 1, further comprising a register roller which is disposed on the downstream side of the U-shaped guide with respect to the feeding direction in which the recording medium is fed, in order to engage a leading edge of the recording medium to correct skew of the recording medium, and wherein the restricting member includes a buckling limit determiner which allows, on the upstream side of the U-shaped guide, buckling of the recording medium whose movement is being inhibited by the register roller, while placing a limit to the buckling.
16. The image recording apparatus according to claim 15, wherein the restricting member includes a feed path defining portion, which is opposed to the slant separator plate at least while the medium pickup roller contacts the bottom plate, in order to cooperate with the slant separator plate to define a feed path along which the recording medium is fed, the feed path defining portion serving as the buckling limit determiner.
17. The image recording apparatus according to claim 1, wherein the restricting member is disposed at a position not to contact the topmost one of the stack of the recording media when the recording media are stacked in a maximum amount in terms of a capacity of the medium supply cassette.
18. An image recording apparatus comprising:
a housing;
a supply cassette having an upper opening which is configured to accommodate a stack of recording sheets, and is inserted into and removed from the housing substantially horizontally in a cassette movement direction, the supply cassette comprises:
a substantially horizontal bottom plate; and
a slant separator plate extending obliquely upward from an edge of the bottom plate;
a pickup device having a pickup roller which is configured to apply a feeding force in a first direction to an uppermost sheet of a stack of recording sheets disposed in a supply cassette, the pickup device is configured to cooperate with the slant separator plate to separate an uppermost sheet from a stack of the recording sheets for feeding in a first feeding direction along a sheet feed path;
a U-shaped guide which changes the feeding direction of the recording sheet from the first feeding direction to a second direction opposite to the first direction;
an image recording portion which records an image on the recording medium as has been passed through the U-shaped guide; and
a restricting member defining a part of the feed path between the pickup roller and the U-shaped guide, the restricting member is configured to contact at least a part of the stack of recording sheets ascending upward along the slant separator plate,
wherein the restricting member is configured to move in a cassette insertion direction when the supply cassette is inserted to restrict the continuing movement of the at least a part of a recording sheet stack disposed in a supply cassette in the cassette insertion direction.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An image forming apparatus comprising:
a transfer unit configured to transfer a toner image to a sheet;
a fixing unit configured to fix the toner image transferred to the sheet on the sheet;
a conveyance unit disposed between the transfer unit and the fixing unit to convey the sheet;
a moving unit configured to move the conveyance unit; and
a control unit configured to controls the moving unit to move the conveyance unit so that a speed of a leading edge of the sheet conveyed from the transfer unit to the fixing unit is reduced, when the leading edge of the sheet reaches the fixing unit.
2. The image forming apparatus according to claim 1,
wherein the conveyance unit conveys the sheet in a state that the conveyance unit suctions the sheet to a conveyance surface of the conveyance unit; and
wherein the control unit controls so that the leading edge of the sheet reaches the fixing unit while moving the conveyance surface of the conveyance unit in the thickness direction of the sheet by the moving unit.
3. The image forming apparatus according to claim 2, further comprising a fixed guiding member disposed between the conveyance unit and the fixing unit to guide the sheet,
wherein a leading edge side of the sheet guided by the guiding member is deformed by moving a downstream side of the conveyance surface of the conveyance unit in a sheet conveyance direction downward by the moving unit.
4. The image forming apparatus according to claim 2, further comprising a guiding member disposed between the conveyance unit and the fixing unit to guide the sheet,
wherein the moving unit moves the conveyance unit so that a portion of a downstream side of the conveyance surface of the conveyance unit in a sheet conveyance direction is separated from the sheet conveyed by the conveyance unit by guiding a leading edge side of the sheet by the guiding member.
5. The image forming apparatus according to claim 2,
wherein the control unit controls the moving unit to move, when a thickness of the conveyed sheet is equal to or more than a predetermined thickness, the conveyance surface of the conveyance unit while the conveyance unit conveys the sheet; and
wherein the control unit controls, when the thickness of the conveyed sheet is less than the predetermined thickness, not to move the conveyance surface of the conveyance unit while the conveyance unit conveys the sheet.
6. The image forming apparatus according to claim 1,
wherein the moving unit moves a downstream side of the conveyance unit in a sheet conveyance direction down or up.
7. The image forming apparatus according to claim 2,
wherein the moving unit swings the conveyance unit between a first position where a sheet conveyance direction by the conveyance unit becomes a first direction and a second position where a sheet conveyance direction of the conveyance unit becomes a second direction downward more than the first direction; and
wherein the control unit performs control in so that, before the leading edge of the sheet conveyed by the conveyance unit set in the first position reaches the fixing unit, the moving unit starts swinging of the conveyance unit from the first position to the second position, and the leading edge of the sheet conveyed by the conveyance unit reaches the fixing unit during the swinging of the conveyance unit from the first position to the second position.
8. The image forming apparatus according to claim 2,
wherein the moving unit swings the conveyance unit between a first position where a sheet conveyance direction of the conveyance unit becomes a first direction and a second position where a sheet conveyance direction of the conveyance unit becomes a second direction upward more than the first direction; and
wherein the control unit performs control so that, before the leading edge of the sheet conveyed by the conveyance unit set in the first position reaches the fixing unit, the moving unit starts swinging of the conveyance unit from the first position to the second position, and the leading edge of the sheet conveyed by the conveyance unit reaches the fixing unit during the swinging of the conveyance unit from the first position to the second position.
9. The image forming apparatus according to claim 1, further comprising a sheet detection unit configured to output a signal in response to detection of the leading edge of the sheet,
wherein when the leading edge of the conveyed sheet is determined to have reached a predetermined position on an upstream side of the fixing unit according to the signal output from the sheet detection unit, the control unit controls the moving unit to start movement of the conveyance unit.
10. The image forming apparatus according to claim 1, further comprising a loop detection unit configured to output a signal according to a loop amount of the sheet between the transfer unit and the fixing unit in a state where the sheet is sandwiched by the transfer unit and the fixing unit,
wherein a sheet conveyance speed by the fixing unit is changed according to the signal output from the loop detection unit.
11. The image forming apparatus according to claim 10,
wherein a relationship of V1<V2 is satisfied, where V1 is a sheet conveyance speed at the transfer unit and V2 is a sheet conveyance speed by the conveyance unit, and
wherein the control unit switches, based on the signal output from the loop detection unit, setting of a sheet conveyance speed V3 at the fixing unit between a speed higher than V1 and a speed lower than V1.
12. The image forming apparatus according to claim 1,
wherein the moving unit moves the conveyance unit so that distortion in the sheet conveyed from the transfer unit to the fixing unit is generated; and
wherein the control unit controls so that the leading edge of the sheet reaches the fixing unit while moving the conveyance unit to generate distortion in the conveyed sheet.
13. The image forming apparatus according to claim 1,
wherein the conveying unit has a conveying belt onto which a sheet is suctioned by a suctioning portion and which conveys the sheet by rotating,
the moving unit swings the conveying belt around a swinging center provided on an upstream side of the conveying belt in a sheet conveyance direction, and
the control unit controls so that the leading edge of the sheet reaches the fixing unit while swinging the conveying belt around the swinging center by the moving unit.