US20200270089A1 - Sheet ejection device and image forming apparatus incorporating the sheet ejection device - Google Patents
Sheet ejection device and image forming apparatus incorporating the sheet ejection device Download PDFInfo
- Publication number
- US20200270089A1 US20200270089A1 US16/787,194 US202016787194A US2020270089A1 US 20200270089 A1 US20200270089 A1 US 20200270089A1 US 202016787194 A US202016787194 A US 202016787194A US 2020270089 A1 US2020270089 A1 US 2020270089A1
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- US
- United States
- Prior art keywords
- sheet
- stacker
- retainer
- ejection device
- image forming
- 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
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H31/00—Pile receivers
- B65H31/04—Pile receivers with movable end support arranged to recede as pile accumulates
- B65H31/08—Pile receivers with movable end support arranged to recede as pile accumulates the articles being piled one above another
- B65H31/10—Pile receivers with movable end support arranged to recede as pile accumulates the articles being piled one above another and applied at 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
- B65H31/00—Pile receivers
- B65H31/04—Pile receivers with movable end support arranged to recede as pile accumulates
- B65H31/12—Devices relieving the weight of the pile or permitting or effecting movement of the pile end support during piling
- B65H31/14—Springs
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H31/00—Pile receivers
- B65H31/26—Auxiliary devices for retaining articles in the pile
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- 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
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- 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
- B65H2511/30—Numbers, e.g. of windings or rotations
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- 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
- B65H2515/10—Mass, e.g. mass flow rate; Weight; Inertia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2801/00—Application field
- B65H2801/03—Image reproduction devices
- B65H2801/06—Office-type machines, e.g. photocopiers
Definitions
- This disclosure relates to a sheet ejection device to eject a sheet such as paper, and an image forming apparatus incorporating the sheet ejection device.
- the image forming apparatus corresponds, for example, to a copier, printer, facsimile machine, printing machine, and a multi-functional apparatus including at least two functions of the copier, printer, facsimile machine, and printing machine.
- Various types of image forming apparatuses such as copiers, printers, and printing machines are known to include a sheet ejection device provided with a sheet stacker (in other words, a sheet tray) that stacks sheets such as papers ejected from the housing of an image forming apparatus.
- a sheet ejection device provided with a sheet stacker (in other words, a sheet tray) that stacks sheets such as papers ejected from the housing of an image forming apparatus.
- Some sheet stackers i.e., sheet trays
- Some sheet stackers are rotatable to appropriately change an angle of a stacker face on which a sheet is stacked while some sheet stackers (i.e., sheet trays) are vertically movable to move in a vertical direction, according to the number of sheets to be stacked on the sheet stacker.
- At least one aspect of this disclosure provides a sheet ejection device including a sheet stacker, a retainer, and a biasing member.
- the sheet stacker has a stacker face and a coupling portion.
- the sheet stacker is configured to stack a sheet on the stacker face.
- the retainer has a coupling portion and an adjuster configured to rotate the sheet stacker to adjust an angle of the stacker face.
- the retainer is configured to retain the sheet stacker to be movable in a vertical direction.
- the biasing member is coupled to the sheet stacker and the retainer and configured to apply a biasing force to bias the sheet stacker in an upward direction to the retainer.
- the sheet stacker is configured to move in a downward direction against the biasing force of the biasing member, as a number of sheets stacked on the stacker face of the sheet stacker increases.
- the coupling portion of the retainer, to which the biasing member is coupled, is configured to move when the adjuster of the retainer rotates the sheet stacker.
- At least one aspect of this disclosure provides an image forming apparatus including an image forming the above-described sheet ejection device.
- the image forming device has a sheet ejection unit configured to eject a sheet.
- the sheet ejection device is configured to stack the sheet ejected by the sheet ejection unit of the image forming device.
- FIG. 1 is a schematic view illustrating an overall configuration of an image forming apparatus according to an embodiment of this disclosure
- FIGS. 2A, 2B, and 2C are schematic side views illustrating operations of a sheet ejection device provided in the image forming apparatus of FIG. 1 ;
- FIGS. 3A, 3B, and 3C are schematic top views illustrating operations of a retainer of the sheet ejection device
- FIGS. 4A and 4B are schematic side views illustrating operations of a comparative sheet ejection device according to a comparative example
- FIG. 5A is a schematic diagram illustrating a sheet ejection device according to Variation of the embodiment of this disclosure.
- FIG. 5B is a schematic diagram illustrating a comparative sheet ejection device according to a comparative configuration of FIG. 5A .
- spatially relative terms such as “beneath”, “below”, “lower”, “above”, “upper” and the like may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements describes as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors herein interpreted accordingly.
- first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layer and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.
- This disclosure is applicable to any sheet ejection device and image forming apparatus and is implemented in the most effective manner in an electrophotographic image forming apparatus.
- an electrophotographic image forming apparatus (hereinafter simply referred to as an image forming apparatus) which forms an image by an electrophotographic system is described as an image forming apparatus including a sheet ejection device according to this disclosure.
- a color laser printer is described as an example of the image forming apparatus.
- the image forming apparatus is not limited to the printer and may be another image forming apparatus such as a copier and a multifunction peripheral.
- the image forming apparatus including the sheet ejection device according to the present embodiment is not limited to the image forming apparatus of the electrophotographic system and may be an image forming apparatus of another system such as an ink jet system.
- FIG. 1 is a schematic view illustrating the image forming apparatus 1 .
- the image forming apparatus 1 may be, e.g., a copier, a facsimile machine, a printer, or a multifunction peripheral (MFP) having at least two of copying, printing, scanning, facsimile, and plotter functions.
- MFP multifunction peripheral
- the term “image forming apparatus” indicates an apparatus in which an image is formed on a recording medium such as paper, OHP (overhead projector) transparencies, OHP film sheet, thread, fiber, fabric, leather, metal, plastic, glass, wood, and/or ceramic by attracting developer or ink thereto;
- image formation indicates an action for providing (i.e., printing) not only an image having meanings such as texts and figures on a recording medium but also an image having no meaning such as patterns on a recording medium;
- the term “sheet” is not limited to indicate a paper material but also includes the above-described plastic material (e.g., an OHP sheet), a fabric sheet and so forth, and is used to which the developer or ink is attracted.
- the “sheet” is not limited to a flexible sheet but is applicable to a rigid plate-shaped sheet and a relatively thick sheet.
- sheet conveying direction indicates a direction in which a recording medium travels from an upstream side of a sheet conveying path to a downstream side thereof
- width direction indicates a direction basically perpendicular to the sheet conveying direction
- the image forming apparatus 1 is a copier in the present embodiment and includes a document reading device 2 , an exposure device 3 , an image forming device 4 , a photoconductor drum 5 , a transfer roller 7 , a transfer conveyance belt 8 , a document conveying unit 10 , an upper sheet feed tray 12 , a lower sheet feed tray 13 , a pair of registration rollers 17 , a fixing device 20 , a fixing roller 21 , a pressure roller 22 , a pair of sheet ejection rollers 25 , a sheet ejection device 30 , and a control display panel 100 .
- the document reading device 2 optically reads image data of an original document D.
- the exposure device 3 emits an exposure light L based on the image data read by the document reading device 2 to irradiate the exposure light L onto a surface of the photoconductor drum 5 that functions as an image bearer.
- the image forming device 4 forms a toner image on the surface of the photoconductor drum 5 .
- the transfer roller 7 contacts the photoconductor drum 5 via the transfer conveyance belt 8 to form a transfer nip region.
- the transfer conveyance belt 8 functions as a transfer unit to transfer the toner image formed on the photoconductor drum 5 , onto a sheet P and conveys the sheet P with the toner image.
- the document conveying unit 10 (the automatic document transfer device) conveys the original document D set on a document tray to the document reading device 2 .
- the upper sheet feed tray 12 and the lower sheet feed tray 13 are sheet trays, each of which contains the sheet P (a recording medium P) such as paper.
- the pair of registration rollers 17 (in other words, a pair of timing rollers) conveys the sheet P toward a transfer nip region.
- the fixing device 20 includes the fixing roller 21 and the pressure roller 22 to fix a toner image (specifically, an unfixed image) formed on the sheet P to the sheet P by application of heat by the fixing roller 21 and pressure by the pressure roller 22 .
- a toner image specifically, an unfixed image
- the pair of sheet ejection rollers 25 functions as a sheet ejection device to convey and eject the sheet P from a housing 1 A of the image forming apparatus 1 .
- the sheet ejection device 30 stacks the sheet P ejected from the housing 1 A of the image forming apparatus 1 .
- the control display panel 100 displays various information functioning on the image forming apparatus 1 and operation buttons (keys) for operating the image forming apparatus 1 .
- the original document D is conveyed (fed) from a document loading table provided to the document conveying unit 10 and conveyed by multiple pairs of sheet conveying rollers disposed in the document conveying unit 10 in a direction indicated by arrow in FIG. 1 , passing over the document reading device 2 .
- the document reading device 2 optically reads image data of the original document D passing over the document reading device 2 .
- the image data optically scanned by the document reading device 2 is converted to electrical signals.
- the converted electrical signals are transmitted to the exposure device 3 (in other words, a writing portion) by which the image is optically written.
- the exposure device 3 emits exposure light L (for example, laser light) based on the image data of the electrical signals, toward the surface of the photoconductor drum 5 of the image forming device 4 .
- the photoconductor drum 5 of the image forming device 4 rotates in a clockwise direction in FIG. 1 .
- a series of predetermined image forming processes e.g., a charging process, an exposing process, and a developing process
- an image for example, a toner image
- a series of predetermined image forming processes e.g., a charging process, an exposing process, and a developing process
- an image for example, a toner image
- the toner image formed on the surface of the photoconductor drum 5 is transferred onto the sheet P that is conveyed by the pair of registration rollers 17 , in the transfer nip region (i.e., a position at which the transfer roller 7 contacts the photoconductor drum 5 via the transfer conveyance belt 8 ).
- one sheet feed tray of the upper sheet feed tray 12 and the lower sheet feed tray 13 of the housing 1 A of the image forming apparatus 1 is selected automatically or manually.
- the upper sheet feed tray 12 that is an uppermost sheet tray is selected, for example.
- the upper sheet feed tray 12 and the lower sheet feed tray 13 basically have an identical configuration to each other. Consequently, when the upper sheet feed tray 12 of the image forming apparatus 1 is selected, an uppermost sheet P contained in the upper sheet feed tray 12 is fed by a sheet feeding mechanism 52 toward a sheet conveyance passage.
- the sheet feeding mechanism 52 includes a sheet feed roller, a pickup roller, a backup roller, and so forth.
- the uppermost sheet P passes through the sheet conveyance passage, in which multiple sheet conveying rollers are disposed, and then reaches the pair of registration rollers 17 .
- the sheet P After reaching the pair of registration rollers 17 , the sheet P is conveyed toward the transfer nip region in synchronization with movement of the toner image formed on the surface of the photoconductor drum 5 for positioning.
- the sheet P passes the position of the transfer nip region, is conveyed by the transfer conveyance belt 8 , and then reaches the fixing device 20 .
- the fixing device 20 the sheet P is conveyed between the fixing roller 21 and the pressure roller 22 , so that the toner image is fixed to the sheet P by application of heat applied by the fixing roller 21 and pressure applied by the fixing roller 21 and the pressure roller 22 , which is a fixing process.
- the sheet P with the toner image fixed to the sheet P in the fixing process is conveyed out from the fixing roller 21 and the pressure roller 22 (in other words, a fixing nip region).
- the sheet P is ejected from the housing 1 A of the image forming apparatus 1 by the pair of sheet ejection rollers 25 , to be stacked as an output image on the sheet stacker 31 (that is, the sheet ejection tray).
- the sheet ejection device 30 is a device on which the sheets P are stacked after the sheets P are conveyed and ejected by the pair of sheet ejection rollers 25 .
- FIGS. 2A, 2B, and 2C are schematic side views illustrating operations of the sheet ejection device 30 .
- the sheet ejection device 30 according to the present embodiment includes a sheet stacker 31 , a retainer 32 , and a compression spring 33 that functions as a biasing member.
- the pair of sheet ejection rollers 25 is disposed in a sheet ejection portion that is an opening formed in the housing 1 A of the image forming apparatus 1 .
- the sheet stacker 31 has a stacker face (that is, a part indicated by a broken line in FIG. 1 ).
- the sheet stacker 31 is configured to stack the sheet P ejected from the pair of sheet ejection rollers 25 , onto the stacker face.
- the retainer 32 is configured to retain the sheet stacker 31 to be movable in a vertical direction of the image forming apparatus 1 .
- the retainer 32 includes a fixed retaining portion 32 a , a rotary retaining portion 32 b , and a movable member 32 c that functions as an adjuster.
- the compression spring 33 is coupled to the sheet stacker 31 and the retainer 32 .
- the compression spring 33 functions as a biasing member to bias the sheet stacker 31 in an upward direction, relative to the retainer 32 .
- the retainer 32 has a coupling portion 32 d (in other words, a receiving portion) and the sheet stacker 31 has a coupling portion 31 d (in other words, a receiving portion).
- One end of the compression spring 33 (that is, a biasing member) is coupled to the coupling portion 32 d of the retainer 32 and an opposed end of the compression spring 33 is coupled to the coupling portion 31 d of the sheet stacker 31 .
- the sheet stacker 31 moves in a downward direction against the biasing force of the compression spring 33 that functions as a biasing member, as the number of sheets P stacked on the stacker face increases.
- the sheet stacker 31 when no sheet P is stacked on (the stacker face of) the sheet stacker 31 , the sheet stacker 31 is lifted and located at an uppermost position due to the biasing force of the compression spring 33 .
- FIG. 2B as the sheet P is stacked one by one into a sheet bundle, on (the stacker face of) the sheet stacker 31 , the sheet stacker 31 gradually lowers against the biasing force of the compression spring 33 , due to an increase in the weight of the sheet bundle.
- the degree of lowering of the sheet stacker 31 (in other words, the amount of the biasing force of the compression spring 33 ) is set to keep a height H 1 from the pair of sheet ejection rollers 25 (i.e., the sheet ejection portion) to the stacker face (specifically, to the top face of an uppermost sheet in a case in which the sheets P are stacked on the stacker face). That is, in FIG. 2B , the spring force of the compression spring 33 , whose length of use M is shrunk from a length of use M 1 to a length of use M 2 , and the weight of the sheets P stacked on the stacker face of the sheet stacker 31 are balanced.
- the posture in which the sheet P ejected by the pair of sheet ejection rollers 25 lands on the stacker face (or the top face of the uppermost sheet P on the stacker face) in a stable posture Therefore, the sheets P are stacked orderly on the sheet stacker 31 , in other words, the stacking performance is enhanced.
- the retainer 32 includes the movable member 32 c that functions as an adjuster to rotate the sheet stacker 31 so as to adjust the angle of the sheet stacker 31 to the housing 1 A of the image forming apparatus 1 .
- the angle of the stacker face of the sheet stacker 31 is an angle of inclination of the sheet P in the sheet conveyance direction (in other words, directions of the leading end to the trailing end of the sheet P).
- the angle of inclination is formed by the stacker face and a horizontal plane with respect to the sheet stacker 31 .
- the retainer 32 includes the fixed retaining portion 32 a , the rotary retaining portion 32 b , and the movable member 32 c that functions as an adjuster.
- the fixed retaining portion 32 a is fixedly retained to the housing of the sheet ejection device 30 (or to the housing 1 A of the image forming apparatus 1 ).
- the coupling portion 32 d that receives the one end side of the compression spring 33 is movably disposed to the fixed retaining portion 32 a .
- the coupling portion 32 d is retained to the fixed retaining portion 32 a by a guide mechanism such that the coupling portion 32 d can slidably move in a direction indicated by white arrow in FIG. 2C or in the opposite direction.
- white arrow in FIG. 2C A detailed description of movement of the coupling portion 32 d is given below.
- the rotary retaining portion 32 b is rotatably held to the fixed retaining portion 32 a .
- the rotary retaining portion 32 b is retained to the fixed retaining portion 32 a by a hinge mechanism such that the rotary retaining portion 32 b can rotate in a direction indicated by broken arrow (that is, a counterclockwise direction) in FIG. 2C or in the opposite direction (that is, a clockwise direction).
- the movable member 32 c functions as an adjuster to rotate the rotary retaining portion 32 b in the direction indicated by the broken arrow in FIG. 2C and the opposite direction by moving in a given direction.
- the rotary retaining portion 32 b rotates in the direction indicated by broken arrow in FIG. 2C (or the opposite direction).
- the sheet stacker 31 rotates in the same direction as the rotary retaining portion 32 b.
- FIG. 2C illustrates a state in which the movable member 32 c , which had been seen at the near side in the direction orthogonal to the drawing sheet of FIG. 2A , has moved to the far side in the direction orthogonal to the drawing sheet and becomes invisible.
- the movable member 32 c (that functions as an adjuster) moves (adjusts) to switch the angle of the sheet stacker 31 between a state in which an angle ⁇ 1 of (the stacker face of) the sheet stacker 31 is large as illustrated in FIGS. 2A and 2B and a state in which an angle ⁇ 2 of (the stacker face of) the sheet stacker 31 is small as illustrated in FIG. 2C .
- This switching of the states is performed because the optimum angles ⁇ of the stacker face to stack the sheets P orderly on the sheet stacker 31 are different depending on types of the sheets P stacked on the sheet stacker 31 .
- the sheets P as plain paper are loaded (stacked) orderly along the inclination of the stacker face, with the stacker face of the sheet stacker 31 having a relatively large angle. Therefore, in a case in which such a sheet P is ejected onto the sheet stacker 31 , the angle of the stacker face of the sheet stacker 31 is set to be the angle ⁇ 1 , as illustrated in FIGS. 2A and 2B .
- a sheet P such as a thin coated paper has low rigidity and a large frictional resistance on the surface. Therefore, if the stacker face has a large angle, it is difficult for the sheet P to move along the inclination of the stacker face smoothly, and therefore the sheet P is bent and curved. Consequently, the sheets P are not loaded (stacked) orderly on the stacker face of the sheet stacker 31 . For this reason, in a case in which such a sheet P is ejected onto the sheet stacker 31 , the angle of the stacker face of the sheet stacker 31 is set to be the angle ⁇ 2 , as illustrated in FIG. 2C .
- the angle ⁇ of the sheet stacker 31 is adjusted from two options.
- the sheet stacker 31 is not limited to the above-described configuration.
- the angle of the sheet stacker 31 may be adjusted from three or more options or may be adjusted to any required angles.
- FIGS. 3A, 3B, and 3C are schematic top views illustrating operations of the retainer 32 of the sheet ejection device 30 and FIGS. 4A and 4B are schematic side views illustrating operations of the sheet ejection device 30 ′ according to a comparative example.
- rotation of the sheet stacker 31 by the movable member 32 c that functions as an adjuster moves the coupling portion 32 d of the retainer 32 that is coupled to the compression spring 33 (that functions as a biasing member).
- the coupling portion 32 d moves to prevent variation of the biasing force of the compression spring 33 .
- the coupling portion 32 d of the retainer 32 moves in the direction indicted by white arrow in FIG. 2C , along with the rotation of the sheet stacker 31 .
- the movable member 32 c rotates the sheet stacker 31 from the state illustrated in FIG.
- the coupling portion 32 d of the retainer 32 slides according to the angle ⁇ of the sheet stacker 31 .
- This operation is performed because, as illustrated in FIGS. 4A and 4B , when the angle ⁇ of the sheet stacker 31 varies, the position of the coupling portion 31 d of the sheet stacker 31 also changes.
- the length of use M of the compression spring 33 significantly changes (i.e., the relation of M 1 ⁇ M 3 ) and, at the same time, the compression spring 33 is retained not in a straight state but in a twisted state between the coupling portion 31 d and the coupling portion 32 d . Therefore, the compression spring 33 does not bias the sheet stacker 31 in the upward direction normally.
- the coupling portion 32 d of the retainer 32 is configured to move along with movement of the movable member 32 c.
- the rotary retaining portion 32 b of the retainer 32 is sufficiently separated apart from the fixed retaining portion 32 a of the retainer 32 (i.e., in FIG. 3A ).
- the movable member 32 c is in contact with a projection of the rotary retaining portion 32 b .
- This state corresponds to a state in which the rotary retaining portion 32 b is retained at a rotational position illustrated in FIG. 2A .
- the coupling portion 32 d of the retainer 32 is pushed by the movable member 32 c toward the right side of FIG.
- the coupling portion 32 d is located at a position illustrated in FIG. 3A , which corresponds to the position illustrated in FIG. 2A .
- the coupling portion 32 d is released from the pushing by the movable member 32 c to slide to the left side of FIG. 3C due to the biasing force of the above-described spring.
- the coupling portion 32 d has a slot 32 d 1 that extends in a longitudinal direction from the lower left side to the upper right side in FIGS. 3A to 3C and that the movable member 32 c has a pin 32 c 1 .
- the pin 32 c 1 of the movable member 32 c is slidably fit into the slot 32 d 1 of the coupling portion 32 d .
- the coupling portion 32 d moves as the pin 32 c 1 is guided to move along the slot 32 d 1 . Consequently, the coupling portion 32 d is operated as described above.
- the sheet stacker 31 and the rotary retaining portion 32 b rotate to set the angle ⁇ of the stacker face to the angle ⁇ 2 and, at the same time, the coupling portion 32 d slides along with the rotation of the sheet stacker 31 and the rotary retaining portion 32 b.
- the sheet ejection device 30 includes guides 34 a and 34 b configured to guide the sheet stacker 31 when the sheet stacker 31 moves in the vertical direction.
- two sets of the guides 34 a and 34 b are disposed on both sides of the housing of the sheet ejection device 30 , in the width direction of the housing of the sheet ejection device 30 (that is, a direction orthogonal to the drawing sheet of FIGS. 2A to 2C ), with interposing the sheet stacker 31 .
- one set of the guides 34 a and 34 b is disposed on one side in the width direction of the housing of the sheet ejection device 30 and the other set of the guides 34 a and 34 b is disposed on the other side in the width direction of the housing of the sheet ejection device 30 .
- the sheet stacker 31 includes shafts 31 a and 31 b , specifically, the shaft 31 a fitting to the guides 34 a and the shaft 31 b fitting to the guides 34 b .
- the guides 34 a and 34 b extend in the direction orthogonal to the drawing sheet of FIGS. 2A to 2C . With the above-described configuration, the sheet stacker 31 is guided by the guides 34 a and 34 b , within the range of movement of the guides 34 a and 34 b , to move in the vertical direction in a stable state.
- FIG. 5A is a schematic diagram illustrating a sheet ejection device 30 A according to Variation of the embodiment of this disclosure.
- FIG. 5B is a schematic diagram illustrating the sheet ejection device 30 A′ according to the comparative example of FIG. 5A .
- the sheet ejection device 30 A includes a stopper 37 that restricts movement of the sheet stacker 31 in the upward direction.
- the stopper 37 is rotatably supported by the fixed retaining portion 32 a to be rotated manually about a support shaft 37 a .
- a tip of the stopper 37 is fit to the shaft 31 a of the sheet stacker 31 , so that the shaft 31 a of the sheet stacker 31 does not move up to an upper end of the guide 34 a , due to the biasing force of the compression spring 33 .
- the sheet stacker 31 is restricted from moving in the upward direction.
- the sheet stacker 31 is restricted from moving in the upward direction because, when the angle ⁇ of the sheet stacker 31 is reduced from the angle ⁇ 1 to the angle ⁇ 2 , as in the sheet ejection device 30 A′ illustrated in FIG. 5B , the height from the position of the pair of sheet ejection rollers 25 to the stacker face is changed from the height H 1 to the height H 2 ( ⁇ H 1 ), which prevents the sheet P from landing on a target position on the stacker face. Therefore, a stacking failure may occur.
- the sheet ejection device 30 A includes the stopper 37 to adjust an uppermost position of the sheet stacker 31 , and therefore, when the angle ⁇ of the sheet stacker 31 is adjusted, occurrence of the above-described stacking failure is reduced.
- the sheet ejection device 30 includes the sheet stacker 31 to stack the sheet(s) P, the retainer 32 to retain the sheet stacker 31 movable in the vertical direction, and the compression spring 33 (that functions as a biasing member) that is coupled to the sheet stacker 31 and the retainer 32 and biases the sheet stacker 31 in the upward direction.
- the sheet stacker 31 moves in the downward direction against the biasing force of the compression spring 33 as the number of sheets P stacked on the stacker face increases.
- the retainer 32 includes the movable member 32 c (that functions as an adjuster) to rotate the sheet stacker 31 so as to adjust the angle ⁇ of the sheet stacker 31 . Consequently, as the movable member 32 c rotates the sheet stacker 31 , the coupling portion 32 d of the retainer 32 to which the compression spring 33 is coupled moves.
- the sheets P are stacked orderly on the sheet stacker 31 .
- the present embodiment of this disclosure is applied to the sheet ejection device 30 provided to the image forming apparatus 1 that performs monochrome image formation.
- this disclosure is not limited to the above-described sheet ejection device (that is, the sheet ejection device 30 ).
- this disclosure is also applicable to a sheet ejection device provided to an image forming apparatus that performs color image formation.
- the present embodiment of this disclosure is applied to the sheet ejection device 30 provided to the image forming apparatus 1 that employs electrophotography.
- this disclosure is not limited to the above-described sheet ejection device (that is, the sheet ejection device 30 and the sheet ejection device 30 A).
- this disclosure is also applicable to a sheet ejection device provided to an image forming apparatus that employs, for example, an inkjet method or a stencil printing machine.
- the present embodiment of this disclosure is applied to the sheet ejection device 30 , which is provided to the image forming apparatus 1 , or to the sheet ejection device 30 A of Variation, for ejecting the sheet P after image formation.
- this disclosure is not limited to the above-described sheet ejection device (that is, the sheet ejection device 30 or the sheet ejection device 30 A).
- this disclosure is also applicable to the document conveying unit 10 (i.e., the automatic document feeder (ADF)) as a sheet ejection device to which the original document D, which functions as a sheet, is ejected.
- ADF automatic document feeder
- a “sheet” in the above-described embodiments of this disclosure is not limited to indicate a (regular) paper but also includes any other sheet-like recording medium such as coated paper, label paper, overhead projector (OHP) sheet, metal sheet, film, prepreg, cloth, and the like.
- OHP overhead projector
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- Paper Feeding For Electrophotography (AREA)
Abstract
A sheet ejection device includes a sheet stacker, a retainer, and a biasing member. The sheet stacker has a stacker face and a coupling portion. The sheet stacker is configured to stack a sheet on the stacker face. The retainer has a coupling portion and an adjuster configured to rotate the sheet stacker to adjust an angle of the stacker face. The retainer is configured to retain the sheet stacker to be movable in a vertical direction. The biasing member is coupled to the sheet stacker and the retainer to apply a biasing force to bias the sheet stacker in an upward direction to the retainer. The sheet stacker is configured to move in a downward direction against the biasing force, as a number of sheets stacked on the stacker face increases. The coupling portion of the retainer is configured to move when the adjuster rotates the sheet stacker.
Description
- This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2019-033696, filed on Feb. 27, 2019, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
- This disclosure relates to a sheet ejection device to eject a sheet such as paper, and an image forming apparatus incorporating the sheet ejection device. The image forming apparatus corresponds, for example, to a copier, printer, facsimile machine, printing machine, and a multi-functional apparatus including at least two functions of the copier, printer, facsimile machine, and printing machine.
- Various types of image forming apparatuses such as copiers, printers, and printing machines are known to include a sheet ejection device provided with a sheet stacker (in other words, a sheet tray) that stacks sheets such as papers ejected from the housing of an image forming apparatus.
- There are various types of sheet stackers. Some sheet stackers (i.e., sheet trays) are rotatable to appropriately change an angle of a stacker face on which a sheet is stacked while some sheet stackers (i.e., sheet trays) are vertically movable to move in a vertical direction, according to the number of sheets to be stacked on the sheet stacker.
- At least one aspect of this disclosure provides a sheet ejection device including a sheet stacker, a retainer, and a biasing member. The sheet stacker has a stacker face and a coupling portion. The sheet stacker is configured to stack a sheet on the stacker face. The retainer has a coupling portion and an adjuster configured to rotate the sheet stacker to adjust an angle of the stacker face. The retainer is configured to retain the sheet stacker to be movable in a vertical direction. The biasing member is coupled to the sheet stacker and the retainer and configured to apply a biasing force to bias the sheet stacker in an upward direction to the retainer. The sheet stacker is configured to move in a downward direction against the biasing force of the biasing member, as a number of sheets stacked on the stacker face of the sheet stacker increases. The coupling portion of the retainer, to which the biasing member is coupled, is configured to move when the adjuster of the retainer rotates the sheet stacker.
- Further, at least one aspect of this disclosure provides an image forming apparatus including an image forming the above-described sheet ejection device. The image forming device has a sheet ejection unit configured to eject a sheet. The sheet ejection device is configured to stack the sheet ejected by the sheet ejection unit of the image forming device.
- An exemplary embodiment of this disclosure will be described in detail based on the following figured, wherein:
-
FIG. 1 is a schematic view illustrating an overall configuration of an image forming apparatus according to an embodiment of this disclosure; -
FIGS. 2A, 2B, and 2C are schematic side views illustrating operations of a sheet ejection device provided in the image forming apparatus ofFIG. 1 ; -
FIGS. 3A, 3B, and 3C are schematic top views illustrating operations of a retainer of the sheet ejection device; -
FIGS. 4A and 4B are schematic side views illustrating operations of a comparative sheet ejection device according to a comparative example; -
FIG. 5A is a schematic diagram illustrating a sheet ejection device according to Variation of the embodiment of this disclosure; and -
FIG. 5B is a schematic diagram illustrating a comparative sheet ejection device according to a comparative configuration ofFIG. 5A . - The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted.
- It will be understood that if an element or layer is referred to as being “on”, “against”, “connected to” or “coupled to” another element or layer, then it can be directly on, against, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, if an element is referred to as being “directly on”, “directly connected to” or “directly coupled to” another element or layer, then there are no intervening elements or layers present. Like numbers referred to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
- Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements describes as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors herein interpreted accordingly.
- Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layer and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.
- The terminology used herein is for describing particular embodiments and examples and is not intended to be limiting of exemplary embodiments of this disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes” and/or “including”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
- Descriptions are given, with reference to the accompanying drawings, of examples, exemplary embodiments, modification of exemplary embodiments, etc., of a sheet ejection device and an image forming apparatus according to exemplary embodiments of this disclosure. Elements having the same functions and shapes are denoted by the same reference numerals throughout the specification and redundant descriptions are omitted. Elements that do not demand descriptions may be omitted from the drawings as a matter of convenience. Reference numerals of elements extracted from the patent publications are in parentheses so as to be distinguished from those of exemplary embodiments of this disclosure.
- This disclosure is applicable to any sheet ejection device and image forming apparatus and is implemented in the most effective manner in an electrophotographic image forming apparatus.
- In describing preferred embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this disclosure is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes any and all technical equivalents that have the same function, operate in a similar manner, and achieve a similar result.
- Referring now to the drawings, embodiments of the present disclosure are described below. In the drawings for explaining the following embodiments, the same reference codes are allocated to elements (members or components) having the same function or shape and redundant descriptions thereof are omitted below.
- Hereinafter, an electrophotographic image forming apparatus (hereinafter simply referred to as an image forming apparatus) which forms an image by an electrophotographic system is described as an image forming apparatus including a sheet ejection device according to this disclosure. In the following embodiments, a color laser printer is described as an example of the image forming apparatus. However, the image forming apparatus is not limited to a color printer but may be a monochrome printer. The image forming apparatus is not limited to the printer and may be another image forming apparatus such as a copier and a multifunction peripheral. The image forming apparatus including the sheet ejection device according to the present embodiment is not limited to the image forming apparatus of the electrophotographic system and may be an image forming apparatus of another system such as an ink jet system.
- Next, a description is given of a configuration and functions of an image forming apparatus according to an embodiment of this disclosure, with reference to drawings. It is to be noted that identical or corresponding parts are given identical reference numerals and redundant descriptions are summarized or omitted accordingly.
- Initially, a description is given of an overall configuration and operations of an image forming apparatus 1 according to an embodiment of the present disclosure, with reference to
FIG. 1 .FIG. 1 is a schematic view illustrating the image forming apparatus 1. The image forming apparatus 1 may be, e.g., a copier, a facsimile machine, a printer, or a multifunction peripheral (MFP) having at least two of copying, printing, scanning, facsimile, and plotter functions. - It is to be noted in the following examples that: the term “image forming apparatus” indicates an apparatus in which an image is formed on a recording medium such as paper, OHP (overhead projector) transparencies, OHP film sheet, thread, fiber, fabric, leather, metal, plastic, glass, wood, and/or ceramic by attracting developer or ink thereto; the term “image formation” indicates an action for providing (i.e., printing) not only an image having meanings such as texts and figures on a recording medium but also an image having no meaning such as patterns on a recording medium; and the term “sheet” is not limited to indicate a paper material but also includes the above-described plastic material (e.g., an OHP sheet), a fabric sheet and so forth, and is used to which the developer or ink is attracted. In addition, the “sheet” is not limited to a flexible sheet but is applicable to a rigid plate-shaped sheet and a relatively thick sheet.
- Further, size (dimension), material, shape, and relative positions used to describe each of the components and units are examples, and the scope of this disclosure is not limited thereto unless otherwise specified.
- Further, it is to be noted in the following examples that: the term “sheet conveying direction” indicates a direction in which a recording medium travels from an upstream side of a sheet conveying path to a downstream side thereof; the term “width direction” indicates a direction basically perpendicular to the sheet conveying direction.
- In
FIG. 1 , the image forming apparatus 1 is a copier in the present embodiment and includes adocument reading device 2, anexposure device 3, animage forming device 4, aphotoconductor drum 5, a transfer roller 7, atransfer conveyance belt 8, adocument conveying unit 10, an uppersheet feed tray 12, a lower sheet feed tray 13, a pair ofregistration rollers 17, a fixing device 20, a fixingroller 21, apressure roller 22, a pair ofsheet ejection rollers 25, asheet ejection device 30, and acontrol display panel 100. Thedocument reading device 2 optically reads image data of an original document D. Theexposure device 3 emits an exposure light L based on the image data read by thedocument reading device 2 to irradiate the exposure light L onto a surface of thephotoconductor drum 5 that functions as an image bearer. - The
image forming device 4 forms a toner image on the surface of thephotoconductor drum 5. The transfer roller 7 contacts thephotoconductor drum 5 via thetransfer conveyance belt 8 to form a transfer nip region. Thetransfer conveyance belt 8 functions as a transfer unit to transfer the toner image formed on thephotoconductor drum 5, onto a sheet P and conveys the sheet P with the toner image. The document conveying unit 10 (the automatic document transfer device) conveys the original document D set on a document tray to thedocument reading device 2. - The upper
sheet feed tray 12 and the lower sheet feed tray 13 are sheet trays, each of which contains the sheet P (a recording medium P) such as paper. The pair of registration rollers 17 (in other words, a pair of timing rollers) conveys the sheet P toward a transfer nip region. - The fixing device 20 includes the fixing
roller 21 and thepressure roller 22 to fix a toner image (specifically, an unfixed image) formed on the sheet P to the sheet P by application of heat by the fixingroller 21 and pressure by thepressure roller 22. - The pair of
sheet ejection rollers 25 functions as a sheet ejection device to convey and eject the sheet P from ahousing 1A of the image forming apparatus 1. Thesheet ejection device 30 stacks the sheet P ejected from thehousing 1A of the image forming apparatus 1. Thecontrol display panel 100 displays various information functioning on the image forming apparatus 1 and operation buttons (keys) for operating the image forming apparatus 1. - Now, a description is given of regular image forming operations performed by the image forming apparatus 1, with reference to
FIG. 1 . - First, the original document D is conveyed (fed) from a document loading table provided to the
document conveying unit 10 and conveyed by multiple pairs of sheet conveying rollers disposed in thedocument conveying unit 10 in a direction indicated by arrow inFIG. 1 , passing over thedocument reading device 2. At this time, thedocument reading device 2 optically reads image data of the original document D passing over thedocument reading device 2. - Consequently, the image data optically scanned by the
document reading device 2 is converted to electrical signals. The converted electrical signals are transmitted to the exposure device 3 (in other words, a writing portion) by which the image is optically written. Then, theexposure device 3 emits exposure light L (for example, laser light) based on the image data of the electrical signals, toward the surface of thephotoconductor drum 5 of theimage forming device 4. - By contrast, the
photoconductor drum 5 of theimage forming device 4 rotates in a clockwise direction inFIG. 1 . After a series of predetermined image forming processes (e.g., a charging process, an exposing process, and a developing process) is completed, an image (for example, a toner image) corresponding to the image data is formed on the surface of thephotoconductor drum 5. - Then, the toner image formed on the surface of the
photoconductor drum 5 is transferred onto the sheet P that is conveyed by the pair ofregistration rollers 17, in the transfer nip region (i.e., a position at which the transfer roller 7 contacts thephotoconductor drum 5 via the transfer conveyance belt 8). - Now, a description is given of how to operate the sheet P conveyed to the transfer nip region.
- First, as illustrated in
FIG. 1 , one sheet feed tray of the uppersheet feed tray 12 and the lower sheet feed tray 13 of thehousing 1A of the image forming apparatus 1 is selected automatically or manually. In the operations according to the present embodiment of this disclosure, the uppersheet feed tray 12 that is an uppermost sheet tray is selected, for example. It is to be noted that the uppersheet feed tray 12 and the lower sheet feed tray 13 basically have an identical configuration to each other. Consequently, when the uppersheet feed tray 12 of the image forming apparatus 1 is selected, an uppermost sheet P contained in the uppersheet feed tray 12 is fed by asheet feeding mechanism 52 toward a sheet conveyance passage. Thesheet feeding mechanism 52 includes a sheet feed roller, a pickup roller, a backup roller, and so forth. The uppermost sheet P passes through the sheet conveyance passage, in which multiple sheet conveying rollers are disposed, and then reaches the pair ofregistration rollers 17. - After reaching the pair of
registration rollers 17, the sheet P is conveyed toward the transfer nip region in synchronization with movement of the toner image formed on the surface of thephotoconductor drum 5 for positioning. - After completion of this transfer process, the sheet P passes the position of the transfer nip region, is conveyed by the
transfer conveyance belt 8, and then reaches the fixing device 20. In the fixing device 20, the sheet P is conveyed between the fixingroller 21 and thepressure roller 22, so that the toner image is fixed to the sheet P by application of heat applied by the fixingroller 21 and pressure applied by the fixingroller 21 and thepressure roller 22, which is a fixing process. The sheet P with the toner image fixed to the sheet P in the fixing process is conveyed out from the fixingroller 21 and the pressure roller 22 (in other words, a fixing nip region). Then, the sheet P is ejected from thehousing 1A of the image forming apparatus 1 by the pair ofsheet ejection rollers 25, to be stacked as an output image on the sheet stacker 31 (that is, the sheet ejection tray). - Thus, a series of the image forming processes is completed.
- Next, a detail description is given of the
sheet ejection device 30 according to the present embodiment. - As described above with reference to
FIG. 1 , thesheet ejection device 30 is a device on which the sheets P are stacked after the sheets P are conveyed and ejected by the pair ofsheet ejection rollers 25. -
FIGS. 2A, 2B, and 2C are schematic side views illustrating operations of thesheet ejection device 30. In reference toFIG. 2A , thesheet ejection device 30 according to the present embodiment includes asheet stacker 31, aretainer 32, and acompression spring 33 that functions as a biasing member. - The pair of
sheet ejection rollers 25 is disposed in a sheet ejection portion that is an opening formed in thehousing 1A of the image forming apparatus 1. Thesheet stacker 31 has a stacker face (that is, a part indicated by a broken line inFIG. 1 ). Thesheet stacker 31 is configured to stack the sheet P ejected from the pair ofsheet ejection rollers 25, onto the stacker face. - The
retainer 32 is configured to retain thesheet stacker 31 to be movable in a vertical direction of the image forming apparatus 1. Theretainer 32 includes a fixed retainingportion 32 a, arotary retaining portion 32 b, and amovable member 32 c that functions as an adjuster. - The
compression spring 33 is coupled to thesheet stacker 31 and theretainer 32. Thecompression spring 33 functions as a biasing member to bias thesheet stacker 31 in an upward direction, relative to theretainer 32. Specifically, theretainer 32 has acoupling portion 32 d (in other words, a receiving portion) and thesheet stacker 31 has acoupling portion 31 d (in other words, a receiving portion). One end of the compression spring 33 (that is, a biasing member) is coupled to thecoupling portion 32 d of theretainer 32 and an opposed end of thecompression spring 33 is coupled to thecoupling portion 31 d of thesheet stacker 31. - Here, in the present embodiment, the
sheet stacker 31 moves in a downward direction against the biasing force of thecompression spring 33 that functions as a biasing member, as the number of sheets P stacked on the stacker face increases. - More specifically, as illustrated in
FIG. 2A , when no sheet P is stacked on (the stacker face of) thesheet stacker 31, thesheet stacker 31 is lifted and located at an uppermost position due to the biasing force of thecompression spring 33. As illustrated inFIG. 2B , as the sheet P is stacked one by one into a sheet bundle, on (the stacker face of) thesheet stacker 31, thesheet stacker 31 gradually lowers against the biasing force of thecompression spring 33, due to an increase in the weight of the sheet bundle. At this time, the degree of lowering of the sheet stacker 31 (in other words, the amount of the biasing force of the compression spring 33) is set to keep a height H1 from the pair of sheet ejection rollers 25 (i.e., the sheet ejection portion) to the stacker face (specifically, to the top face of an uppermost sheet in a case in which the sheets P are stacked on the stacker face). That is, inFIG. 2B , the spring force of thecompression spring 33, whose length of use M is shrunk from a length of use M1 to a length of use M2, and the weight of the sheets P stacked on the stacker face of thesheet stacker 31 are balanced. - Accordingly, regardless of the number of sheets P stacked on the stacker face, the posture in which the sheet P ejected by the pair of
sheet ejection rollers 25 lands on the stacker face (or the top face of the uppermost sheet P on the stacker face) in a stable posture. Therefore, the sheets P are stacked orderly on thesheet stacker 31, in other words, the stacking performance is enhanced. - Further, in the present embodiment, the
retainer 32 includes themovable member 32 c that functions as an adjuster to rotate thesheet stacker 31 so as to adjust the angle of thesheet stacker 31 to thehousing 1A of the image forming apparatus 1. It is to be noted that the angle of the stacker face of thesheet stacker 31 is an angle of inclination of the sheet P in the sheet conveyance direction (in other words, directions of the leading end to the trailing end of the sheet P). The angle of inclination is formed by the stacker face and a horizontal plane with respect to thesheet stacker 31. - To be more specific, the
retainer 32 includes the fixed retainingportion 32 a, therotary retaining portion 32 b, and themovable member 32 c that functions as an adjuster. - The fixed retaining
portion 32 a is fixedly retained to the housing of the sheet ejection device 30 (or to thehousing 1A of the image forming apparatus 1). Thecoupling portion 32 d that receives the one end side of thecompression spring 33 is movably disposed to the fixed retainingportion 32 a. Specifically, thecoupling portion 32 d is retained to the fixed retainingportion 32 a by a guide mechanism such that thecoupling portion 32 d can slidably move in a direction indicated by white arrow inFIG. 2C or in the opposite direction. A detailed description of movement of thecoupling portion 32 d is given below. - The
rotary retaining portion 32 b is rotatably held to the fixed retainingportion 32 a. Specifically, therotary retaining portion 32 b is retained to the fixed retainingportion 32 a by a hinge mechanism such that therotary retaining portion 32 b can rotate in a direction indicated by broken arrow (that is, a counterclockwise direction) inFIG. 2C or in the opposite direction (that is, a clockwise direction). - The
movable member 32 c functions as an adjuster to rotate therotary retaining portion 32 b in the direction indicated by the broken arrow inFIG. 2C and the opposite direction by moving in a given direction. As themovable member 32 c moves, therotary retaining portion 32 b rotates in the direction indicated by broken arrow inFIG. 2C (or the opposite direction). Then, along with the rotation of therotary retaining portion 32 b, thesheet stacker 31 rotates in the same direction as therotary retaining portion 32 b. - It is to be noted that
FIG. 2C illustrates a state in which themovable member 32 c, which had been seen at the near side in the direction orthogonal to the drawing sheet ofFIG. 2A , has moved to the far side in the direction orthogonal to the drawing sheet and becomes invisible. - As described above, in the present embodiment of this disclosure, the
movable member 32 c (that functions as an adjuster) moves (adjusts) to switch the angle of thesheet stacker 31 between a state in which an angle θ1 of (the stacker face of) thesheet stacker 31 is large as illustrated inFIGS. 2A and 2B and a state in which an angle θ2 of (the stacker face of) thesheet stacker 31 is small as illustrated inFIG. 2C . - This switching of the states is performed because the optimum angles θ of the stacker face to stack the sheets P orderly on the
sheet stacker 31 are different depending on types of the sheets P stacked on thesheet stacker 31. - To be more specific, the sheets P as plain paper are loaded (stacked) orderly along the inclination of the stacker face, with the stacker face of the
sheet stacker 31 having a relatively large angle. Therefore, in a case in which such a sheet P is ejected onto thesheet stacker 31, the angle of the stacker face of thesheet stacker 31 is set to be the angle θ1, as illustrated inFIGS. 2A and 2B . - By contrast, a sheet P such as a thin coated paper has low rigidity and a large frictional resistance on the surface. Therefore, if the stacker face has a large angle, it is difficult for the sheet P to move along the inclination of the stacker face smoothly, and therefore the sheet P is bent and curved. Consequently, the sheets P are not loaded (stacked) orderly on the stacker face of the
sheet stacker 31. For this reason, in a case in which such a sheet P is ejected onto thesheet stacker 31, the angle of the stacker face of thesheet stacker 31 is set to be the angle θ2, as illustrated inFIG. 2C . - It is to be noted that, in the present embodiment of this disclosure, the angle θ of the
sheet stacker 31 is adjusted from two options. However, thesheet stacker 31 is not limited to the above-described configuration. For example, the angle of thesheet stacker 31 may be adjusted from three or more options or may be adjusted to any required angles. - Here,
FIGS. 3A, 3B, and 3C are schematic top views illustrating operations of theretainer 32 of thesheet ejection device 30 andFIGS. 4A and 4B are schematic side views illustrating operations of thesheet ejection device 30′ according to a comparative example. In the present embodiment of this disclosure, rotation of thesheet stacker 31 by themovable member 32 c (that functions as an adjuster) moves thecoupling portion 32 d of theretainer 32 that is coupled to the compression spring 33 (that functions as a biasing member). - To be more specific, as the
movable member 32 c (an adjuster) rotates thesheet stacker 31, thecoupling portion 32 d moves to prevent variation of the biasing force of thecompression spring 33. To be more specific, as themovable member 32 c rotates thesheet stacker 31 from the state illustrated inFIG. 2A to the state illustrated inFIG. 2C and the angle θ of thesheet stacker 31 changes from the angle θ1 to the angle θ2, thecoupling portion 32 d of theretainer 32 moves in the direction indicted by white arrow inFIG. 2C , along with the rotation of thesheet stacker 31. By contrast, as themovable member 32 c rotates thesheet stacker 31 from the state illustrated inFIG. 2C to the state illustrated inFIG. 2A and the angle θ of thesheet stacker 31 changes from the angle θ2 to the angle θ1, thecoupling portion 32 d of theretainer 32 moves in the opposite direction to the direction indicted by white arrow inFIG. 2C , along with the rotation of thesheet stacker 31. - As described above, the
coupling portion 32 d of theretainer 32 slides according to the angle θ of thesheet stacker 31. This operation is performed because, as illustrated inFIGS. 4A and 4B , when the angle θ of thesheet stacker 31 varies, the position of thecoupling portion 31 d of thesheet stacker 31 also changes. Along with this change, the length of use M of thecompression spring 33 significantly changes (i.e., the relation of M1≠M3) and, at the same time, thecompression spring 33 is retained not in a straight state but in a twisted state between thecoupling portion 31 d and thecoupling portion 32 d. Therefore, thecompression spring 33 does not bias thesheet stacker 31 in the upward direction normally. If a biasing failure is caused by thecompression spring 33 as described above, this failure impairs the function in which thesheet stacker 31 moves in the downward direction along with an increase in the number of sheets P, as explained with reference toFIGS. 2A and 2B . As a result, a stacking failure of the sheet P occurs easily. - By contrast, in the present embodiment of this disclosure, even when the angle θ of the
sheet stacker 31 changes, the length of use M1 of thecompression spring 33 seldom varies, and thecoupling portion 32 d of theretainer 32 slides such that thecompression spring 33 is maintained substantially in the straight state between the two coupling portions, which are thecoupling portion 31 d of thesheet stacker 31 and thecoupling portion 32 d of theretainer 32. Accordingly, the above-described biasing failure occurs less. - Here, in the present embodiment, the
coupling portion 32 d of theretainer 32 is configured to move along with movement of themovable member 32 c. - More specifically, when the angle θ of the
sheet stacker 31 is the angle θ1 (i.e., in the state illustrated inFIGS. 2A and 2B ), therotary retaining portion 32 b of theretainer 32 is sufficiently separated apart from the fixed retainingportion 32 a of the retainer 32 (i.e., inFIG. 3A ). At this time, themovable member 32 c is in contact with a projection of therotary retaining portion 32 b. This state corresponds to a state in which therotary retaining portion 32 b is retained at a rotational position illustrated inFIG. 2A . Thecoupling portion 32 d of theretainer 32 is pushed by themovable member 32 c toward the right side ofFIG. 3A , against the biasing force of a spring that biases theretainer 32 toward the left side ofFIG. 3A . Consequently, thecoupling portion 32 d is located at a position illustrated inFIG. 3A , which corresponds to the position illustrated inFIG. 2A . - Then, as the
movable member 32 c is manually moved from the position ofFIG. 3A to the position ofFIG. 3B , the contact of themovable member 32 c with the projection of therotary retaining portion 32 b is cancelled (in other words, themovable member 32 c is separated from the projection of therotary retaining portion 32 b), and therotary retaining portion 32 b moves to approach the fixed retainingportion 32 a and rotates to the rotational position illustrated inFIG. 2C . - Thereafter, as illustrated in
FIG. 3C , when therotary retaining portion 32 b is brought to contact the fixed retainingportion 32 a, thecoupling portion 32 d is released from the pushing by themovable member 32 c to slide to the left side ofFIG. 3C due to the biasing force of the above-described spring. It is to be noted that thecoupling portion 32 d has aslot 32 d 1 that extends in a longitudinal direction from the lower left side to the upper right side inFIGS. 3A to 3C and that themovable member 32 c has apin 32 c 1. Thepin 32 c 1 of themovable member 32 c is slidably fit into theslot 32 d 1 of thecoupling portion 32 d. Thecoupling portion 32 d moves as thepin 32 c 1 is guided to move along theslot 32 d 1. Consequently, thecoupling portion 32 d is operated as described above. Thus, as illustrated inFIG. 2C , thesheet stacker 31 and therotary retaining portion 32 b rotate to set the angle θ of the stacker face to the angle θ2 and, at the same time, thecoupling portion 32 d slides along with the rotation of thesheet stacker 31 and therotary retaining portion 32 b. - It is to be noted that, when the
sheet stacker 31 is rotated from the state illustrated inFIG. 2C to the state illustrated inFIG. 2A , thesheet stacker 31 is rotated manually in the reverse order of the procedure described above with reference toFIGS. 3A to 3C . - Referring to
FIG. 2A , thesheet ejection device 30 according to the present embodiment includesguides sheet stacker 31 when thesheet stacker 31 moves in the vertical direction. - To be more specific, in the present embodiment, two sets of the
guides sheet ejection device 30, in the width direction of the housing of the sheet ejection device 30 (that is, a direction orthogonal to the drawing sheet ofFIGS. 2A to 2C ), with interposing thesheet stacker 31. In other words, one set of theguides sheet ejection device 30 and the other set of theguides sheet ejection device 30. Thesheet stacker 31 includesshafts shaft 31 a fitting to theguides 34 a and theshaft 31 b fitting to theguides 34 b. Theguides FIGS. 2A to 2C . With the above-described configuration, thesheet stacker 31 is guided by theguides guides - Variation.
-
FIG. 5A is a schematic diagram illustrating asheet ejection device 30A according to Variation of the embodiment of this disclosure.FIG. 5B is a schematic diagram illustrating thesheet ejection device 30A′ according to the comparative example ofFIG. 5A . - As illustrated in
FIG. 5A , thesheet ejection device 30A according to Variation includes astopper 37 that restricts movement of thesheet stacker 31 in the upward direction. - More specifically, the
stopper 37 is rotatably supported by the fixed retainingportion 32 a to be rotated manually about asupport shaft 37 a. As thestopper 37 is rotated to the position illustrated inFIG. 5A , a tip of thestopper 37 is fit to theshaft 31 a of thesheet stacker 31, so that theshaft 31 a of thesheet stacker 31 does not move up to an upper end of theguide 34 a, due to the biasing force of thecompression spring 33. By so doing, thesheet stacker 31 is restricted from moving in the upward direction. - The
sheet stacker 31 is restricted from moving in the upward direction because, when the angle θ of thesheet stacker 31 is reduced from the angle θ1 to the angle θ2, as in thesheet ejection device 30A′ illustrated inFIG. 5B , the height from the position of the pair ofsheet ejection rollers 25 to the stacker face is changed from the height H1 to the height H2 (<H1), which prevents the sheet P from landing on a target position on the stacker face. Therefore, a stacking failure may occur. - In Variation, the
sheet ejection device 30A includes thestopper 37 to adjust an uppermost position of thesheet stacker 31, and therefore, when the angle θ of thesheet stacker 31 is adjusted, occurrence of the above-described stacking failure is reduced. - It is to be noted that, when the angle θ of the
sheet stacker 31 is increased from the angle θ2 from the angle θ1 in Variation, thestopper 37 is rotated in order to cancel the above-described restriction of thestopper 37. - As described above, the
sheet ejection device 30 according to the present embodiment includes thesheet stacker 31 to stack the sheet(s) P, theretainer 32 to retain thesheet stacker 31 movable in the vertical direction, and the compression spring 33 (that functions as a biasing member) that is coupled to thesheet stacker 31 and theretainer 32 and biases thesheet stacker 31 in the upward direction. Thesheet stacker 31 moves in the downward direction against the biasing force of thecompression spring 33 as the number of sheets P stacked on the stacker face increases. Theretainer 32 includes themovable member 32 c (that functions as an adjuster) to rotate thesheet stacker 31 so as to adjust the angle θ of thesheet stacker 31. Consequently, as themovable member 32 c rotates thesheet stacker 31, thecoupling portion 32 d of theretainer 32 to which thecompression spring 33 is coupled moves. - According to this configuration, regardless of the number or types of the sheets P stacked on the
sheet stacker 31, the sheets P are stacked orderly on thesheet stacker 31. - It is to be noted that the present embodiment of this disclosure is applied to the
sheet ejection device 30 provided to the image forming apparatus 1 that performs monochrome image formation. However, this disclosure is not limited to the above-described sheet ejection device (that is, the sheet ejection device 30). For example, this disclosure is also applicable to a sheet ejection device provided to an image forming apparatus that performs color image formation. - Further, it is to be noted that the present embodiment of this disclosure is applied to the
sheet ejection device 30 provided to the image forming apparatus 1 that employs electrophotography. However, this disclosure is not limited to the above-described sheet ejection device (that is, thesheet ejection device 30 and thesheet ejection device 30A). For example, this disclosure is also applicable to a sheet ejection device provided to an image forming apparatus that employs, for example, an inkjet method or a stencil printing machine. - Furthermore, it is to be noted that the present embodiment of this disclosure is applied to the
sheet ejection device 30, which is provided to the image forming apparatus 1, or to thesheet ejection device 30A of Variation, for ejecting the sheet P after image formation. However, this disclosure is not limited to the above-described sheet ejection device (that is, thesheet ejection device 30 or thesheet ejection device 30A). For example, this disclosure is also applicable to the document conveying unit 10 (i.e., the automatic document feeder (ADF)) as a sheet ejection device to which the original document D, which functions as a sheet, is ejected. - Further, even when the above-described sheet ejection devices are applied, these sheet ejection devices can achieve the same effect as the effect provided by the configuration(s) in the present embodiment.
- It is to be noted that the above-described embodiments are illustrative and do not limit this disclosure. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements at least one of features of different illustrative and exemplary embodiments herein may be combined with each other at least one of substituted for each other within the scope of this disclosure and appended claims. Further, features of components of the embodiments, such as the number, the position, and the shape are not limited the above-described embodiments and thus may be preferably set.
- It is to be noted that a “sheet” in the above-described embodiments of this disclosure is not limited to indicate a (regular) paper but also includes any other sheet-like recording medium such as coated paper, label paper, overhead projector (OHP) sheet, metal sheet, film, prepreg, cloth, and the like.
- The effects described in the embodiments of this disclosure are listed as most preferable effects derived from this disclosure, and therefore are not intended to limit to the embodiments of this disclosure.
- The embodiments described above are presented as an example to implement this disclosure. The embodiments described above are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, or changes can be made without departing from the gist of the invention. These embodiments and their variations are included in the scope and gist of this disclosure, and are included in the scope of the invention recited in the claims and its equivalent.
- Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
Claims (8)
1. A sheet ejection device comprising:
a sheet stacker having a stacker face and a coupling portion,
the sheet stacker configured to stack a sheet on the stacker face;
a retainer having a coupling portion and an adjuster configured to rotate the sheet stacker to adjust an angle of the stacker face,
the retainer configured to retain the sheet stacker to be movable in a vertical direction; and
a biasing member coupled to the sheet stacker and the retainer and configured to apply a biasing force to bias the sheet stacker in an upward direction to the retainer,
the sheet stacker being configured to move in a downward direction against the biasing force of the biasing member, as a number of sheets stacked on the stacker face of the sheet stacker increases,
the coupling portion of the retainer, to which the biasing member is coupled, being configured to move when the adjuster of the retainer rotates the sheet stacker.
2. The sheet ejection device according to claim 1 ,
wherein the coupling portion of the retainer moves to prevent the biasing force of the biasing member from varying when the adjuster rotates the sheet stacker.
3. The sheet ejection device according to claim 1 ,
wherein the retainer includes:
a fixed retaining portion on which the coupling portion of the retainer is movably disposed;
a rotary retaining portion rotatably held relative to the fixed retaining portion; and
a movable member that is the adjuster configured to move in a given direction to rotate the rotary retaining portion; and
wherein the coupling portion of the retainer is configured to move along with movement of the movable member.
4. The sheet ejection device according to claim 1 , further comprising:
a guide configured to guide the sheet stacker in movement in the vertical direction.
5. The sheet ejection device according to claim 1 , further comprising:
a stopper configured to restrict movement of the sheet stacker in the upward direction.
6. The sheet ejection device according to claim 1 ,
wherein the adjuster is configured to be operated manually.
7. The sheet ejection device according to claim 1 ,
wherein the biasing member is a compression spring.
8. An image forming apparatus comprising:
an image forming device configured form an image on a sheet;
a sheet ejection unit configured to eject the sheet on which the image is formed by the image forming device; and
the sheet ejection device according to claim 1 , configured to stack the sheet ejected by the sheet ejection unit.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2019033696A JP7269546B2 (en) | 2019-02-27 | 2019-02-27 | Discharge device and image forming device |
JP2019-033696 | 2019-02-27 |
Publications (1)
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US20200270089A1 true US20200270089A1 (en) | 2020-08-27 |
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US16/787,194 Abandoned US20200270089A1 (en) | 2019-02-27 | 2020-02-11 | Sheet ejection device and image forming apparatus incorporating the sheet ejection device |
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US (1) | US20200270089A1 (en) |
JP (1) | JP7269546B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20200371465A1 (en) * | 2019-05-21 | 2020-11-26 | Ricoh Company, Ltd. | Sheet stacker and image forming apparatus incorporating the sheet stacker |
US11339022B2 (en) * | 2019-05-14 | 2022-05-24 | Ricoh Company, Ltd. | Sheet stacker and image forming apparatus incorporating the sheet stacker |
US11420837B2 (en) | 2019-11-29 | 2022-08-23 | Ricoh Company, Ltd. | Sheet placement device, sheet feeding device, and image forming apparatus |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03113355U (en) * | 1990-03-06 | 1991-11-19 | ||
JP2000191215A (en) * | 1998-12-24 | 2000-07-11 | Ricoh Co Ltd | Sheet loading device |
JP4747613B2 (en) * | 2004-03-15 | 2011-08-17 | 富士ゼロックス株式会社 | Paper processing device |
JP5621585B2 (en) * | 2010-12-27 | 2014-11-12 | 株式会社リコー | Image forming apparatus |
-
2019
- 2019-02-27 JP JP2019033696A patent/JP7269546B2/en active Active
-
2020
- 2020-02-11 US US16/787,194 patent/US20200270089A1/en not_active Abandoned
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11339022B2 (en) * | 2019-05-14 | 2022-05-24 | Ricoh Company, Ltd. | Sheet stacker and image forming apparatus incorporating the sheet stacker |
US20200371465A1 (en) * | 2019-05-21 | 2020-11-26 | Ricoh Company, Ltd. | Sheet stacker and image forming apparatus incorporating the sheet stacker |
US11687022B2 (en) * | 2019-05-21 | 2023-06-27 | Ricoh Company, Ltd. | Sheet stacker and image forming apparatus incorporating the sheet stacker |
US11420837B2 (en) | 2019-11-29 | 2022-08-23 | Ricoh Company, Ltd. | Sheet placement device, sheet feeding device, and image forming apparatus |
Also Published As
Publication number | Publication date |
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JP7269546B2 (en) | 2023-05-09 |
JP2020138816A (en) | 2020-09-03 |
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