Patent Grant
9758324
Field of the Invention
The present invention relates to a sheet conveyance apparatus for conveying sheets, and an image forming apparatus equipped with the same.
Description of the Related Art
Hitherto, image forming apparatuses, such as printers, are equipped with a sheet feeding apparatus, having sheets for recording images stacked on a tray and capable of separating and feeding the sheets one by one. Japanese Patent Application Laid-Open Publication No. 2003-118865 discloses a sheet feeding apparatus having a guide member for guiding sheets toward a separation nip for separating and feeding sheets one by one. The guide member is constituted movably when a bundle of sheets are fed.
Now, a conventional sheet feeding apparatus will be described with reference to
Further, the sheet feeding apparatus 301 is equipped with a nip guide 363 preventing the sheet S from being caught between a sheet cassette 300 and the separation nip N and jammed. The nip guide 363 is supported rotatably on a rotating shaft 363a, and biased toward a direction approaching the feed roller 353 (direction of arrow J2) by a tension spring 366.
As shown in
On the other hand, when multiple sheets S forming a bundle is sent out from the sheet cassette 300, a large amount of load is applied to the nip guide 363 from the bundle of sheets S. Thereby, as shown in
Meanwhile, Japanese Patent Application Laid-Open Publication No. S63-225043 teaches a sheet feeding apparatus equipped with a separating roller frame holding a separating roller (retard roller) in a swingable manner, and a feed-in guide plate supported rotatably on a separating roller frame and guiding the sheet to the separation nip. The feed-in guide plate is designed to rotate downward to prevent jamming of sheets when a large number of sheets are fed between the feed-in guide plate and a feed roller forming the separation nip together with the separating roller.
As described above, according to the sheet feeding apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2003-118865, the given angle θ between the nip guide 363 and the sheet S varies depending on the level of load applied to the nip guide 363 from the sheet S. For example, if a card board is fed from the sheet cassette 300, the nip guide 363 is pressed by the card board and rotates downward easily. Then, when the nip guide 363 is pressed by the sheet S and is migrated in a direction of arrow O, the abutting angle in which the front end of the sheet S abuts against the peripheral surface of the retard roller 364 is increased.
In order to correspond to the downsizing of recent printers, there is a tendency to minimize the outer diameter of the retard roller 364. In that case, the given angle θ between the nip guide 363 and the sheet S is changed, and the abutting angle between the front end of the sheet S and the peripheral surface of the retard roller 364 is increased significantly. Generally, the peripheral surface of the retard roller 364 is formed of a material having a high friction coefficient, so that if the front end of the sheet S collides against the retard roller 364 with a great abutting angle, the front end of the sheet S may be damaged greatly, or jamming of the sheet S may occur.
In the sheet feeding apparatus disclosed in Japanese Patent Application Laid-Open Publication No. S63-225043, the range of rotation of the feed-in guide plate is regulated by an upper limit stopper and a lower limit stopper disposed on a separating roller frame. The space between the upper limit stopper and the lower limit stopper is small, and the range of rotation of the feed-in guide plate is narrow. When the feed-in guide plate is pressed by a large number of sheets and rotates downward, the feed-in guide plate abuts against the upper limit stopper, but when the feed-in guide plate rotates further downward, the separating roller frame rotates downward together with the feed-in guide plate. Then, the separating roller held in the separating roller frame will be separated from the feed roller, and there is fear that the large number of sheets cannot be separated one by one and overlapped feeding may occur.
According to one aspect of this disclosure, a sheet conveyance apparatus includes a stacking portion on which sheets are stacked, a rotator conveying a sheet by rotating in a contact state with the sheet stacked on the stacking portion, a separating member pressing the rotator and separating the sheets one by one at a contact portion where the rotator and the separating member contact each other, a holder holding the separating member, a guide portion rotatably provided with the holder and capable of guiding a front end of the sheet to the contact portion, the guide portion configured to rotate in a direction separating from the rotator in a state where the separating member presses the rotator, and a regulating portion regulating the guide portion from rotating in a direction approaching the rotator in a state where the guide portion contacts against the regulating portion.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Now, Embodiment 1 of the present invention will be described. A printer 1 (image forming apparatus) according to the preferred embodiment of the present invention is an electro-photographic laser beam printer forming four-color toner images. The printer 1 has, as shown in
When an image forming command is output to the printer 1, an image forming process by the image forming portion 30 is started based on image information entered from an external computer and the like connected to the printer 1. The image forming portion 30 is equipped with a scanner unit 31, and four process cartridges 32Y, 32M, 32C and 32Bk for forming four color images of yellow (Y), magenta (M), cyan (C) and black (Bk). The four process cartridges 32Y, 32M, 32C and 32Bk have the same configuration, except for the differences in the color of the formed images, so only the image forming process of process cartridge 32Y will be described, and descriptions of process cartridges 32M, 32C and 32Bk are omitted.
The scanner unit 31 irradiates laser beams to the photosensitive drum 33 of the process cartridge 32Y based on the entered image information. At this time, the photosensitive drum 33 is charged in advance by a charging roller, not shown, and by irradiating laser beams thereto, an electrostatic latent image is formed on the photosensitive drum 33. Thereafter, the electrostatic latent image is developed by a developing roller 35, and a yellow (Y) toner image is formed on the photosensitive drum 33.
Similarly, magenta (M), cyan (C) and black (Bk) toner images are also formed on the photosensitive drums of process cartridges 32M, 32C and 32Bk. The toner images of respective colors formed on the respective photosensitive drums are transferred via primary transfer rollers 36Y, 36M, 36C and 36Bk to an intermediate transfer belt 37, and conveyed via the intermediate transfer belt 37 rotating in direction M to a secondary transfer roller 38. The image forming processes of the respective colors are performed at matched timings so that the images are respectively overlapped on an upstream toner image primarily transferred to the intermediate transfer belt 37.
In parallel with the above-described image forming operation, the sheet stored in the cassette sheet feed portion 10 or the sheet stacked on the manual sheet feed portion 50 is fed one by one to a registration roller 15. Then, the toner image on the intermediate transfer belt 37 is transferred via the secondary transfer roller 38 onto the sheet conveyed by the registration roller 15 at a given conveyance timing. The toner image transferred onto the sheet is fixed at a fixing portion 39, and the sheet is then discharged via a discharge roller pair 40 onto a discharge tray 41.
When forming images on both sides of a sheet, the sheet having an image formed on a first side thereof by the secondary transfer roller 38 is guided toward an inverting roller pair 43 via a switching member 42, turned over by the inverting roller pair 43, and guided to a duplex conveyance path 44. Then, the sheet is conveyed again to the registration roller 15, where an image is formed on a second side thereof by the secondary transfer roller 38, and the sheet is discharged onto the discharge tray 41.
Next, the manual sheet feed portion 50 as a sheet conveyance apparatus will be described with reference to
Further, the intermediate plate 56 must be separated from the feed roller 53 by a distance equal to or greater than a maximum sheet stacking height each time the sheet feed operation is completed, to enable sheets to be stacked additionally whenever a stacked sheet is fed. Therefore, as shown in
During the state where the feed roller 53 is in a standby state, the cam followers 56a and 56a of the intermediate plate 56 are pushed down by the elevating cams 58 and 58, and sheets can be stacked on the intermediate plate 56. When the clutch is in an engaged state and the feed roller shaft 53c is rotated, the cam followers 56a and 56a slide along the elevating cams 58 and 58 and the intermediate plate 56 is elevated by the intermediate plate spring 57. Then, the uppermost sheet S of the sheet bundle Sa stacked on the intermediate plate 56 abuts against the feed roller 53, and the sheet S is fed via the feed roller 53. When the feed roller 53 rotates once, the sheet S is conveyed via the conveyance roller pair 55 and 55 arranged downstream in the sheet feed direction, and the intermediate plate 56 will be pushed down again by the elevating cams 58 and 58.
When the feed roller 53 rotates once to have the sheet S conveyed by the conveyance roller pair 55 and 55, the sheet S conveyed by the conveyance roller pair 55 and 55 slides against the stopped feed roller 53, causing uneven wear of a feed roller rubber 53a covering an outer peripheral surface of the feed roller 53. Therefore, the feed roller 53 is equipped with the feed roller rubber 53a formed in a D-cut shape, and driven feed rollers 53b and 53b supported in a rotatable manner on both ends in an axial direction of the feed roller rubber 53a. The driven feed rollers 53b and 53b are formed to have a smaller outer diameter than the feed roller rubber 53a, and the driven feed rollers protrude in an outer diameter direction from the roller covered by the feed roller rubber 53a only at areas where the feed roller rubber 53a are subjected to D-cut.
During the standby state, the feed roller 53 stands by at a position where the driven feed rollers 53b and 53b contact the sheet S, and when the sheet S is conveyed by the conveyance roller pair 55 and 55, the sheet S does not slide against the feed roller rubber 53a. Thus, uneven wear of the feed roller rubber 53a can be prevented, and the life of the feed roller 53 can be elongated.
As shown in
A nip guide 63 (guide member) is disposed between the separation nip N and the sheet bundle Sa stacked on the intermediate plate 56, and the nip guide 63 is supported rotatably to the separating roller holder 60 around a rotation fulcrum 63a. A front end guide 63b (pressure surface) for guiding the sheet S smoothly to the separation nip N is formed on the upper surface of the nip guide 63, and a guide surface 63c (abutting surface) is formed on the right side surface of the nip guide 63 to which the front end of the sheet S contacts.
The nip guide 63 is biased upward by a nip guide spring (second biasing member), and positioned at an abutting position where the nip guide abuts against a stopper 65 (regulating portion) provided to the separating roller holder 60. The nip guide spring 64 is disposed in a compressed manner between the nip guide 63 and the separating roller holder 60. In the state where the nip guide 63 is at an abutting position, the front end guide 63b and an outer peripheral surface of the feed roller 53 are separated by a given distance H1. On the right side of the nip guide 63 is formed the above-mentioned guide surface 63c, and a sheet non-contact surface 63d formed below the guide surface 63c (refer to
In other words, the sheet non-contact surface 63d is formed so that the nip guide 63 shown in
Therefore, according to the present embodiment, the abutment surface 52a is formed on the sheet feed frame 52 so as to prevent sheets from abutting against the sheet non-contact surface 63d and to make it difficult for the sheet bundle thicker than the given distance H1 to enter the separation nip N. Thus, it becomes possible to prevent the ends of sheets from being damaged and improve the separation performance of the sheets. Further, the abutment surface 52a is formed to abut against the sheet bundle Sa stacked on the intermediate plate 56 approximately perpendicularly, and prevent the sheet bundle Sa from being damaged when the intermediate plate 56 is lifted or lowered. When a sheet abuts against the guide surface 63c of the nip guide 63, force acts on the nip guide 63 so that the nip guide 63 in
Next, a series of actions of the manual sheet feed portion 50 will be described with reference to
Now, we will describe two cases, a case where a single sheet S of the sheet bundle Sa is fed by the feed roller 53, and a case where multiple sheets S are fed, with reference to
Therefore, the nip guide 63 receives a pressing force in a direction of arrow Q in the guide surface 63c, and attempts to rotate in a counterclockwise direction around the rotation fulcrum 63a as fulcrum, but the stopper 65 restricts the rotation in the counterclockwise direction (direction approximating the feed roller 53). Thus, the nip guide 63 is held at the abutting position abutted against the stopper 65.
Therefore, even when various types of sheets having different stiffness, such as thin paper and thick paper, are fed, the position of the nip guide 63 will not vary, and the front end guide 63b of the nip guide 63 will not move away from the feed roller 53, increasing the contact angle between the front end of the sheet S and the separating roller 54. Thus, the front end of the sheet S will not collide against the separating roller 54 by the enlarged contact angle between the front end of the sheet S and the separating roller 54, and the damaging of the front end of the sheet S can be reduced. Furthermore, it becomes possible to prevent the sheet S from running into the separating roller 54 and causing jamming.
Now, when a single sheet S is fed to the separation nip N, the friction force between the feed roller 53 and the separating roller 54 causes a torque limiter not shown built into the separating roller 54 to rotate idly. Thereby, the separating roller 54 is driven to rotate by the sheet S conveyed to a sheet feed direction, and the sheet S is conveyed to the downstream side.
Next, we will describe examples where multiple sheets S are fed in a bundle by the feed roller 53. There are two such cases, which are described below.
A first case is an example where a few sheets from the upper portion of the sheet bundle Sa surpass the guide surface 63c and are conveyed to the separation nip N, as shown in
In that case, similar to the case where a single sheet S is fed to the separation nip N, the nip guide 63 receives a pressing force in the direction of arrow Q (sheet conveyance direction) in the guide surface 63c and attempts to rotate in the counterclockwise direction, though the rotating motion is restricted by the stopper 65. The number of sheets S having surpassed the guide surface 63c passes between the feed roller 53 and the front end guide 63b, and is conveyed to the separation nip N. At this time, since the friction force between the sheets S is small compared to the load of a torque limiter not shown, the separating roller 54 will not rotate, and the number of sheets S can be separated into single sheets at the separation nip N. Thereby, among the number of sheets fed from the intermediate plate 56, only the uppermost sheet S is conveyed downstream in the conveyance direction, and the other sheets are stopped by the ceased separating roller 54 and stay at the separation nip N.
A second case is an example where the thickness T1 of the number of sheets S having surpassed the guide surface 63c is equal to or greater than the given distance H1 (T1≧H1), as shown in
When the nip guide 63 rotates in the clockwise direction, the nipping force of the nip guide 63 and the feed roller 53 applied on the bundle of sheets S will only be the force generated by the biasing force of the nip guide spring 64. As a result, the nipping force of the bundle of sheets S is reduced. When the bundle of sheets S reaches the separation nip N in this state, the separating roller 54 will not rotate since the friction force among the sheets S is small compared to the load of the torque limiter not shown, and therefore, the bundle of sheets S can be sorted. Then, only the uppermost sheet out of the bundle of sheets S is conveyed downstream in the sheet conveyance direction.
The position of the rotation fulcrum 63a of the nip guide 63 is determined to be at the position illustrated in
We will now describe, as a comparative example, a configuration where the rotation fulcrum 63a of the nip guide 63 is not arranged in area C, with reference to
In such case, the nip guide 163 rotates in the clockwise direction by the pressing force in a direction of arrow U of the sheet bundle Sa in contact with a guide surface 163c. Then, the given distance H1 between a front end guide 163b and the feed roller 53 is widened, and an abutting angle between the front end of the sheets S surpassing the guide surface 163c and abutted against the separating roller 54 and the peripheral surface of the separating roller 54 is increased significantly. Since the friction coefficient of the peripheral surface of the separating roller 54 is set high, when the front end of the sheet S collides against the separating roller 54 with a high abutting angle, serious damage may be caused to the front end of the sheet, or jamming of the sheet may occur.
Next, as shown in
Therefore, according to the present embodiment, the rotation fulcrum 63a of the nip guide 63 is arranged in area C, so that pressing force from the sheet bundle Sa acts on the guide surface 63c of the nip guide 63, and the nip guide 63 attempts to rotate in the counterclockwise direction. However, since the nip guide 63 is positioned at an abutting position by the stopper 65, the front end of the sheet will not collide against the separating member in a state where the abutting angle between the front end of the conveyed sheet S and the peripheral surface of the separating roller 54 is great. Thus, damage to the front end of the sheet can be reduced, and the occurrence of jamming of the sheet by the sheet wedging into the separating member can be prevented.
Further, when the bundle of sheets S having a thickness equal to or greater than the given distance H1 is sandwiched between the front end guide 63b of the nip guide 63 and the feed roller 53, the nip guide 63 rotates in the clockwise direction, opposing to the biasing force of the nip guide spring 64. At this time, the biasing force of the separation spring 61 disposed in a compressed manner between the separating roller holder 60 and the bottom panel 52b of the sheet feed frame 52 (refer to
Therefore, even when the nip guide 63 rotates in the clockwise direction, the separating roller holder 60 will not rotate together with the nip guide 63. Thus, a state is maintained where the separating roller 54 presses the feed roller 53, so that the sheets can be separated one by one without fail. Further, it is possible to prevent the bundle of sheets S from being clogged between the front end guide 63b of the nip guide 63 and the feed roller 53 and causing jamming.
According further to the present embodiment, the rotation fulcrum 63a of the nip guide 63 and the stopper 65 are provided on the separating roller holder 60. This is because the feed roller 53 is composed of the feed roller rubber 53a and the driven feed rollers 53b having different outer diameters, and the diameters of the areas in contact with the separating roller 54 vary while the feed roller 53 rotates once.
Now, as a comparative example, we will describe an example where a rotation fulcrum of a nip guide and a stopper are disposed on the sheet feed frame 52 as rotation fulcrum 463a and stopper 465, with reference to
When the driven feed rollers 53b and the front end guide 63b oppose each other, as shown in
Further, when the feed roller rotates once, the diameter of the feed roller 53 is varied at the separation nip N, so that the separating roller 54 and the separating roller holder 60 rotates in accordance with the diameter of the feed roller 53. This rotation of the separating roller 54 and the separating roller holder 60 is performed before the sheet S reaches the separation nip N. However, according to this comparative example, since the rotation fulcrum 463a and the stopper 465 are disposed on the sheet feed frame 52, the nip guide 63 will not follow the separating roller holder 60 even when the separating roller holder 60 rotates.
As shown in
Therefore, the present embodiment adopts a configuration as shown in
The present embodiment adopts a configuration where the separating roller 54 is pushed down by the feed roller rubber 53a, but it is also possible to adopt a configuration where a tapered surface having a low friction coefficient is formed on an upstream side in the direction of rotation of the feed roller rubber 53a, and the tapered surface pushes down the separating roller 54. According to this configuration, the separating roller 54 and the separating roller holder 60 can be pushed down without fail before the sheet S reaches the separation nip N, and damaging of the front end of the sheet S can be prevented.
Further, the guide surface 63c is formed to be abutted approximately perpendicularly against the sheet bundle Sa stacked on the intermediate plate 56 in the state where the nip guide 63 is abutted against the stopper 65. In other words, the guide surface 63c is formed along a direction approximately to the sheet conveyance direction. Thus, it is possible to prevent the front end of the sheet bundle Sa from being damaged due to the guide surface 63c sliding against the sheet bundle Sa by the separating roller holder 60 being rotated and the nip guide 63 following the movement. The term approximately perpendicular or approximately orthogonal does not necessary refer to an angle of 90 degrees, and can be any angle between 80 and 100 degrees, for example.
Moreover, the front end guide 63b is formed to be approximately in parallel with the sheet bundle Sa stacked on the intermediate plate 56 in the state where the nip guide 63 is abutted against the stopper 65. In other words, the front end guide 63b is formed approximately in parallel with the sheet conveyance direction. Therefore, the reaction force of the nipping force acting on the front end guide 63b from the bundle of sheets S sandwiched between the front end guide 63b and the feed roller 53 acts in a balanced manner across the whole surface of the front end guide 63b. According to this configuration, the nip guide 63 can be rotated smoothly, and the surface of the sheet S can be prevented from being damaged by having force concentrate to a portion of the surface of the sheet S.
The term approximately parallel does not necessary refer to a state where the angle between the front end guide 63b and the sheet bundle Sa is 0 degrees, and for example, the sheet S can be guided smoothly to the separation nip N by slightly inclining the sheet to approach the separation nip N toward the downstream side in the sheet conveyance direction.
Next, the position of the rotation fulcrum 60a of the separating roller holder 60 will be described with reference to
Further, the rotation fulcrum 60a is arranged on a downstream side in the sheet conveyance direction than a normal line G of the separation nip N, that is, a line perpendicular to a tangent of the feed roller 53 and the separating roller 54 in the separation nip N. As described, the area on a side close to the feed roller 53 with respect to the third straight line D, on a side far from the feed roller 53 with respect to the fourth straight line E, and on a downstream side in the sheet conveyance direction than the normal line G (shaded area in the drawing) is referred to as area F.
In the present embodiment, the rotation fulcrum 60a of the separating roller holder 60 is positioned within area F, so that the pressing force in a direction of arrow Q acting on the guide surface 63c from the sheet bundle Sa1 or the sheet bundle Sa2 during feeding of the sheet acts roughly toward the rotation fulcrum 60a. Therefore, this pressing force acting on the separating roller holder 60 via the nip guide 63 restricted of movement by the stopper 65 does not act as a rotational moment of the separating roller holder 60. Thereby, even if the thickness of the sheet bundle Sa stacked on the intermediate plate 56 is varied, a contact pressure (separation pressure) of the separation nip N during sheet feed will not change, and the sheet S can be separated one by one in a stable manner.
As described, according to the present embodiment, when various types of sheets Shaving different stiffness enter the guide surface 63c of the nip guide 63, the nip guide 63 will not rotate regardless of whether the sheet S is a bundle or a single sheet, and the sheet can be guided to the separation nip N without the front end of the sheet being damaged.
When the bundle of sheets S is sandwiched between the front end guide 63b of the nip guide 63 and the feed roller 53, the nip guide 63 rotates in the direction moving away from the feed roller 53. At this time, the separating roller holder 60 will not rotate together with the nip guide 63, and the state is maintained where the separating roller 54 presses the feed roller 53. Thereby, overlapped feeding of the sheet S can be prevented, and occurrence of jamming can be prevented.
According to this configuration, the sheet S can reliably be separated one by one and conveyed to the image forming portion 30, in correspondence with the increase in speed, downsizing, and the diversification of the printer or other image forming apparatuses.
Next, Embodiment 2 of the present invention will be described, wherein components that are the same as Embodiment 1 described above are denoted with the same reference numbers in the drawings, and detailed descriptions thereof are omitted. As shown in
Therefore, when the nip guide 63 is rotated in the clockwise direction opposing to the biasing force of the nip guide spring 664, hardly any force acts on the separating roller holder 60. Therefore, the freedom of design of the nip guide spring 664 and the separation spring 61 can be improved.
Next, Embodiment 3 of the present invention will be described, wherein components that are the same as Embodiment 1 described above are denoted with the same reference numbers in the drawings, and detailed descriptions thereof are omitted. In Embodiment 3, a nip guide is composed of two members.
As shown in
The nip guide 563 is biased upward by the nip guide spring 64 (second biasing member), and positioned at an abutting position where it is abutted against the stopper 65 (regulating portion) disposed on the separating roller holder 60. The nip guide spring 64 is disposed in a compressed manner between the nip guide 563 and the separating roller holder 60. When the nip guide 563 is in the abutting position, the front end guide 63b and the outer peripheral surface of the feed roller 53 are separated by a given distance H1.
As shown in
An engaging claw 72a (second engaging portion) is provided on the guide member 70b, and an engaging groove 72b (first engaging portion) is provided on the support member 70a, wherein the engaging claw 72a and the engaging groove 72b constitute a snap-fit 72. By the engagement of the engaging claw 72a and the engaging groove 72b, the guide member 70b is positioned at the mounted position. When the guide member 70b is at the mounted position, the guide member 70b rotates integrally with the support member 70a around the rotation fulcrum 63a.
In the present embodiment, the engaging claw is disposed on the guide member 70b and the engaging groove is disposed on the support member 70a, but it is merely necessary to provide the engaging claw to either the guide member 70b or the support member 70a, and to provide the engaging groove to the other member. Further, the configuration and shape of the snap-fit 72 is not restricted.
The guide member 70b can be moved to the opened position as shown in
In the mounted position, the guide member 70b is pressed onto the stopper 65 by the nip guide spring 64 disposed in a compressed manner between a spring seat surface 73 and the separating roller holder 60. By being abutted against the cylindrical stopper 65, the guide member 70b has a first regulating surface 74 regulating the movement around the rotation fulcrum 63a toward a direction approximating the feed roller 53, and a second regulating surface 75 regulating the movement toward the sheet conveyance direction.
As shown in
Next, as a comparative example, a case where either one of the first regulating surface 74 or the second regulating surface 75 is provided to the guide member 70b will be described with reference to
When the amount of movement of the upper end of the guide member 170b is increased, the guide member 170b and the separating roller 54 may contact each other, preventing the rotation of the separating roller 54. When the front end of the sheet contacts the separating roller 54 in the state where the separating roller 54 is stopped, the front end of the sheet cannot enter the separation nip N since the friction coefficient of the peripheral surface of the separating roller 54 is too high, and jamming or damaging of the front end of the sheet occurs.
In consideration of the above-described problems of the comparative example, in the present embodiment, as shown in
As described, the present invention enables to provide a sheet conveyance apparatus capable of infallibly separating the sheets S one by one without damaging the sheets S and having superior exchangeability of the separating roller, capable of corresponding to the increase in speed and downsizing of printers and other image forming apparatuses, and the diversification of the media being used.
According to a preferred embodiment, a configuration can be adopted where the guide member 70b is detachably mounted to the support member 70a.
According to the three preferred embodiments illustrated above, the stopper 65 can be composed integrally with the separating roller holder 60, or an independent member can be fixed to the separating roller holder 60. Moreover, the stopper 65 can be fixed to a member other than the separating roller holder 60.
According to the three embodiments described above, the manual sheet feed portion 50 equipped with the feed roller 53 and the separating roller 54 has been illustrated as an example, but similar effects can be achieved by adopting the following sheet feed system. For example, it is possible to use a pickup roller to feed sheets, and have a feed roller and a separating roller separate the sheets one by one. For example, it is possible to use a retard roller (separating roller) that rotates in a direction opposite to the sheet feed direction instead of the separating roller, or to separate the sheets one by one using a non-rotating member such as a separating pad (separating member).
Furthermore, the present invention can be applied not only to manual sheet feeding portions, but also to cassette-type cassette sheet feeding portions. Further, the present invention can be applied to sheet feeding apparatuses having a sheet stacked directly on a sheet tray without a liftable intermediate plate.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2014-246302, filed Dec. 4, 2014, and Japanese Patent Application No. 2014-246301, filed Dec. 4, 2014, which are hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-246301 | Dec 2014 | JP | national |
| 2014-246302 | Dec 2014 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4852868 | Fukui et al. | Aug 1989 | A |
| 7040614 | Sonoda | May 2006 | B2 |
| 7731177 | Ikeda | Jun 2010 | B2 |
| 7980551 | Kobayashi | Jul 2011 | B2 |
| 8973918 | Muramatsu et al. | Mar 2015 | B2 |
| 9242820 | Machii | Jan 2016 | B2 |
| 9394126 | Sakamoto | Jul 2016 | B2 |
| 20080309001 | Muramatsu | Dec 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 63-225043 | Sep 1988 | JP |
| 2003-118865 | Apr 2003 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20160159591 A1 | Jun 2016 | US |
