JP5164632B2 - Sheet feeding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding apparatus and an image forming apparatus, and more particularly to a configuration of a stacking amount regulating member that regulates a stacking amount of sheets stored in a sheet storage unit.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines and laser beam printers include a sheet feeding device that feeds sheets one by one from a sheet storage unit in which a plurality of sheets are stored. As a conventional sheet feeding apparatus, a sheet cassette as a sheet storage unit is detachably attached to the apparatus main body, and sheets stored in the sheet cassette are automatically fed to an image forming unit by a pickup roller. It is common to make it.

  By the way, as such a sheet feeding apparatus, there is a swinging type apparatus in which a pickup roller is disposed above a sheet feeding cassette and is swingable in a vertical direction. In such a swing type conventional sheet feeding apparatus, when the sheet feeding cassette is mounted, the middle plate incorporated in the sheet feeding cassette is lifted from the lowest position by driving on the apparatus main body side.

  When the middle plate rises as described above, the uppermost sheet is eventually pressed against the pickup roller, and when the middle plate further rises, the pickup roller also rises. After that, when the pickup roller rises to a predetermined position, the intermediate plate stops. The position where the middle plate stops is a position where an appropriate feeding pressure is applied to the upper surface of the sheet by the pickup roller when feeding the sheet, and the sheet is reliably fed by stopping the middle plate at such a position. be able to.

  Here, as a method of raising the intermediate plate, in addition to a method of raising the intermediate plate while keeping it horizontal, as shown in FIG. 13, the intermediate plate 101 is centered on the rotation shaft 102 on the upstream side in the sheet feeding direction. There is a method of rotating upward. When the sheet S stored in the paper feed cassette 100 is fed by the pickup roller 103, the intermediate plate 101 at the standby position shown in FIG. 13A is moved as shown in FIG. The sheet is rotated upward so that the downstream side in the sheet feeding direction rises around the rotation shaft 102.

  As a sheet feeding cassette including such an intermediate plate 101, the rear end in the sheet feeding direction (hereinafter referred to as “sheet feeding direction”) of sheets stored as shown in FIGS. 14A and 14B so that sheets of different sizes can be stored. A rear end regulating plate 108 for regulating the position of the rear end). Further, side regulating plates 106 and 107 are provided for regulating the side end position of the sheet in the direction orthogonal to the sheet feeding direction (hereinafter referred to as the width direction). The side regulating plates 106 and 107 are movable in the width direction, and the rear end regulating plate 108 is configured to be movable in the sheet feeding direction.

  In such a paper feeding cassette, the side edge of the sheet is regulated by the side regulating plates 106 and 107, while the trailing edge is regulated by the trailing edge regulating plate 108, and the leading edge position of the sheet is always regulated to a predetermined position. Like to do. As a result, when the sheet feeding cassette is stored in the apparatus main body, stable sheet feeding can be performed regardless of the sheet size.

  When the sheet is replenished, an operation is performed to pull out the paper feed cassette 100. When the paper feed cassette is pulled out in this way, the drive on the apparatus main body side is released, and FIG. As shown in (), the rising middle plate is pushed down. After the paper cassette 100 is pulled out in this way, the user performs the sheet supply and storage operation to the cassette 100 by aligning the positions of the side regulating plates 106 and 107 and the trailing edge regulating plate 108 according to the size of the sheet to be used. .

  By the way, in the conventional sheet feeding cassette, as shown in FIGS. 15A and 15B, a stacking amount regulating member 109 for preventing the sheets from being overloaded is provided on the upper portion of the trailing end regulating plate 108. (See Patent Document 1). Note that the stacking amount regulating member 109 also serves to regulate that the inclined sheet S slides backward when the intermediate plate 101 rotates upward with the rotation shaft 102 as a fulcrum.

JP-A-11-165484

  By the way, in the conventional sheet feeding apparatus provided with such a sheet feeding cassette 100, diversification of corresponding sheet sizes has been demanded in recent years. For this reason, for example, it is necessary to be able to cope with a small-sized sheet having a length about half of the length in the sheet feeding direction of the sheet storage portion of the conventional sheet feeding cassette, such as an A6 size sheet. .

  However, in the case of a sheet feeding cassette provided with a rotatable middle plate as in the prior art, when storing a small-sized sheet, as shown in FIGS. 16A and 16B, the rear end regulating plate 108 is used. May be downstream of the rotation axis 102 of the intermediate plate 101 in the sheet feeding direction.

  In this case, the sheet S is stored until the upper surface comes into contact with the stacking amount regulating member 109. When the sheet feeding cassette 100 is loaded in this state, the sheet S is picked up by the pickup roller 103 as shown in FIG. The middle plate 101 is rotated and moved up to a position where an appropriate paper feeding pressure is applied. With this movement, the trailing edge of the sheet S stacked on the middle plate 101 also rises together with the middle plate 101. At this time, the trailing edge of the sheet S does not follow the movement of the middle plate 101. It is pressed from above by the regulating member 109.

  When the sheet feeding operation is performed as shown in FIG. 17B in the state where the trailing end is pressed down by the stacking amount regulating member 109 as described above, the stacking amount regulating member 109 is placed at the trailing end. In some cases, the sheet S may not be fed. Further, even if the sheet S is fed, there may be a case where the rear end portion of the sheet has a scar due to being pressed by the stacking amount regulating member 109 or causes skewing.

  Accordingly, the present invention has been made in view of such a current situation, and an object thereof is to provide a sheet feeding device and an image forming apparatus that can reliably feed a sheet having a size shorter than the middle plate. It is what.

The present invention includes a sheet feeding cassette for storing sheets, and a sheet feeding member disposed above the sheet feeding cassette mounted on the apparatus main body, and the sheets stored in the sheet feeding cassette are fed to the sheet feeding unit. In the sheet feeding apparatus that presses against a feeding member and feeds the sheet by the sheet feeding member, the sheet feeding cassette is supported by a cassette main body that stores sheets, and a vertical rotation on the cassette main body by a rotating shaft. An intermediate plate that presses the stacked sheets against the sheet feeding member by rotating upward , and is provided in the cassette body so as to be movable in the sheet feeding direction, and the sheets stored in the cassette body regulation and trailing edge regulating member, the trailing edge regulating member provided to protrude toward the downstream side in the sheet feeding, the stacking amount of sheets stored in the cassette body to regulate the rear end position That the stacking amount limiting member, and a spring biasing in the direction opposite to the upward rotation back to the position for regulating the amount of the sheets stacked in the stacking amount limiting member is rotated upward, the sheet feeding The intermediate plate is mounted in a state where the cassette is mounted on the apparatus main body, and the rear end restricting member restricts the sheets stacked on the intermediate plate downstream in the sheet feeding direction from the position of the rotation shaft. when rotated upward, the loading amount regulating member is provided in the rear end regulating member to move by being pressed by the rear end of the sheet for raising the upper, elastic force of the spring, the loading amount controlling The size is set such that the sheet can be fed even when the member rotates upward .

  As in the present invention, when the load regulating member is pressed against the rear end of the sheet that rises as the middle plate rotates upward, the pressure contact force with the rear end of the sheet is reduced. Thus, a sheet having a size shorter than that of the intermediate plate can be reliably fed.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention.

  In FIG. 1, reference numeral 200 denotes an image forming apparatus, and 201 denotes an image forming apparatus main body (hereinafter referred to as an apparatus main body). The apparatus body 201 includes an image forming unit 200A, and a sheet feeding unit that feeds sheets S such as recording sheets stacked and stored in the sheet feeding cassette 100 to the image forming unit 201 at the lower part of the apparatus body 201. A device 200B is provided.

  Here, the image forming unit 200A includes a process cartridge 202 including a photosensitive drum 203, a charger 211, a developing sleeve (not shown), a cleaning unit, and the like. Also provided is a laser scanner 212 which is an exposure means for exposing the surface of the photosensitive drum 203 to form an electrostatic latent image on the photosensitive drum 203.

  In addition, the apparatus main body 201 includes a transfer roller 204 that is in contact with the photosensitive drum 203 and forms a transfer unit together with the photosensitive drum 203, a fixing unit 205 that fixes the toner image transferred by the transfer unit to the sheet S, and the like. Yes.

  The sheet feeding device 200B separates the pickup roller 103, which is a sheet feeding member that feeds the sheet S stacked in the sheet feeding cassette 100 from the uppermost side, and the sheet S fed by the pickup roller 103, one by one. And a roller 104. The apparatus body 201 also serves as the apparatus body of the sheet feeding apparatus 200B.

  Next, an image forming operation in the image forming apparatus 200 configured as described above will be described.

  When the image forming operation is started, first, the photosensitive drum 203 is rotated in the direction of the arrow and the surface is charged by the charger 211. Thereafter, the optical aperture shown in FIG. Laser light is emitted based on the image information via the unit 213. Thereby, an electrostatic latent image is formed on the photosensitive drum.

  Next, the electrostatic latent image is developed and supplied with toner that has been appropriately charged as the developing sleeve (not shown) rotates and is supplied onto the photosensitive drum 203 and adheres to the electrostatic latent image. Visualized as an image.

  On the other hand, the pickup roller 103 rotates in parallel with such a toner image forming operation, and sends the uppermost sheet S on the paper feed cassette 100. Then, the sheet S sent out by the pickup roller 103 in this way is conveyed while being separated by the separation roller 104, and the leading edge position alignment (skew correction) is performed by the stopped registration roller pair 210.

  Next, the sheet S is conveyed to the transfer unit by the registration roller pair 210 so that the timing is synchronized with the image formed on the photosensitive drum 203 in the image forming unit 200A, and the image on the photosensitive drum 203 is transferred to the sheet S by the transfer roller 204. Is transferred to. Note that a toner image formed on the photosensitive drum 203 is transferred to the sheet S by applying a voltage having a reverse polarity to the toner image to the transfer roller 204, and then residual toner on the photosensitive drum 203 is removed by a cleaning unit (not shown). Remove.

  Next, the sheet S onto which the toner image has been transferred in this manner is conveyed to a fixing nip formed by a heating roller 206 and a pressure roller 207 provided in the fixing unit 205, where the unfixed toner image is heated and heated. Pressurized and fixed on the sheet surface. The sheet S on which the toner image has been fixed in this manner is discharged onto the discharge tray 209 by the discharge roller 208.

  When images are formed on both sides of the sheet S, the sheet S with the image fixed on the surface is reversed and conveyed by the reversing conveyance unit 200C and conveyed to the transfer unit. Is transferred to the back side of the sheet S. Then, the image transferred on the back surface is thermally fixed by the fixing unit 205, and then the sheet S on which the image is fixed on the back surface is discharged to the tray 209 by the paper discharge roller 208.

  By the way, the paper feed cassette 100 is detachably attached to the apparatus main body 201. 3A shows a state in which the paper feed cassette 100 is pulled out from the apparatus main body 201, and FIG. 3B shows a state in which the paper feed cassette 100 is stored in the apparatus main body 201. .

  Here, as shown in FIG. 4, the sheet feeding cassette 100 is provided with a cassette body 100a for stacking and storing sheets of various sizes, and an intermediate plate on which the sheet S is stacked so as to be rotatable in the vertical direction on the cassette body 100a. 101. The intermediate plate 101 rotates around a rotation shaft 102 on the upstream side in the sheet feeding direction, and the sheet S stacked on the intermediate plate 101 is picked up by a pickup roller disposed above the sheet feeding cassette 100. 103 can be pressed.

  Further, the sheet feeding cassette 100 includes a right side regulating plate 106 that regulates the position in the width direction of the sheet, a left side regulating plate 107, and a rear end regulating plate 108 that is a rear end regulating member that regulates the rear end position of the sheet. I have. The left and right side regulating plates 106 and 107 are configured to be movable in the width direction, and the rear end regulating plate 108 is configured to be movable in the sheet feeding direction.

  By the way, in order to prevent overloading of sheets, in other words, in order to regulate the stacking amount of sheets, a stacking amount restricting member 109 protrudes on the downstream side in the sheet feeding direction in order to prevent the sheets from being overloaded. Yes. Here, when the amount of sheets stored in the sheet feeding cassette 100 reaches a predetermined amount, the stacking amount regulating member 109 comes into contact with the upper surface of the rear end portion of the sheet. Can be regulated. Note that when the intermediate plate 101 that is rotatably supported by the rotation shaft 102 is rotated upward about the rotation shaft 102, the sheet S that is inclined together with the intermediate plate 101 moves backward. It also plays a role in regulating sliding down.

  Here, in the present embodiment, the load amount regulating member 109 is centered on the pivot fulcrum 111 with respect to the rear end regulating plate 108 as shown in FIGS. 5 (a), 5 (b) and 5 (c). It has a rotatable structure. Further, the stacking amount regulating member 109 is urged toward the side pressing the upper surface of the stacking sheet by a spring 112 which is an elastic member.

  The spring 112 causes the stacking amount regulating member 109 to return to a position where the stacking amount of sheets is regulated by being biased in the opposite direction when rotated upward as will be described later. Further, the load amount regulating member 109 biased by the spring 112 in this way is positioned at a right angle to the rear end regulating plate 108 by a stopper (not shown), in other words, as shown in FIG. It is held at a position parallel to the middle plate 101 in the lowered position.

  In addition, by biasing the stacking amount regulating member 109 with the spring 112 in this way, when the amount of sheets to be stored is too large, the sheets are stored while the stacking amount regulating member 109 is rotated upward. . That is, if the amount of sheets is too large, the sheets cannot be stored unless the stacking amount regulating member 109 is rotated upward. If the sheets cannot be stored unless the stacking amount regulating member 109 is pushed up, the sheets are stored. The user can determine that the amount of sheets is too large.

  Next, an operation for storing a sheet in the sheet feeding cassette 100 including the stacking amount regulating member 109 having such a configuration and an operation for feeding the sheet will be described.

  For example, when storing a sheet longer than the length of the middle plate 101, first, the side regulating plates 106 and 107 and the rear end regulating plate 108 are aligned according to the size of the sheet, and the sheet is accommodated in the sheet feeding cassette 100. Thereafter, the paper feed cassette 100 is mounted on the apparatus main body 201.

  Here, when the sheet cassette 100 is stored in this way, the middle plate 101 that has been positioned at the lowered position where the sheet S can be stored as shown in FIG. As shown in b), the device is rotated upward about the rotation shaft 102 by a drive (not shown) on the apparatus main body side. Then, when the intermediate plate 101 rotates upward as described above, the sheet S is eventually pressed against the pickup roller 103.

  Further, when the intermediate plate 101 is raised, the pickup roller 103 is also raised. Thereafter, when the pickup roller 103 is raised to a predetermined position, the intermediate plate 101 is stopped. The position where the middle plate 101 stops is a position where an appropriate feeding pressure is applied to the upper surface of the sheet S by the pickup roller 103 during sheet feeding. When the middle plate 101 stops at such a position, The sheet S can be reliably sent out.

  On the other hand, when storing sheets shorter than the length of the middle plate 101, first, the sheets are stored in the sheet feeding cassette 100 by matching the positions of the side regulating plates 106 and 107 and the trailing end regulating plate 108 according to the size of the sheet. Thereafter, the paper feed cassette 100 is mounted on the apparatus main body 201. Here, when such a small-sized sheet is supplied to the sheet feeding cassette 100, the position of the rear end regulating plate 108 is set to the rotation axis of the middle plate 101 as shown in FIGS. It is downstream of the position 102 in the sheet feeding direction.

  After that, when the paper feed cassette 100 is mounted on the apparatus main body 201, as shown in FIG. 8A, the intermediate plate 101 rotates upwardly about the rotation shaft 102, and thus the intermediate plate 101 is thus formed. Is rotated upward, the sheet S is eventually pressed against the pickup roller 103. Further, when the intermediate plate 101 is raised, the pickup roller 103 is also raised. Thereafter, when the pickup roller 103 is raised to a predetermined position, the intermediate plate 101 is stopped.

  By the way, when the small plate is stacked on the middle plate, if the middle plate 101 rotates upward, the rear end portion of the sheet S also rises together with the middle plate 101 as the middle plate 101 rotates upward. Go. When the sheet S is stored in the sheet feeding cassette 100 until the sheet S comes into contact with the stacking amount regulating member 109 or close to the stacking amount regulating member 109, the stacking amount is increased by the rear end portion of the sheet S that is lifted together with the intermediate plate 101. The regulating member 109 is pressed from below.

  Here, when the sheet S is pressed from below by the rear end portion of the sheet S as described above, the stacking amount regulating member 109 rotates while being resisted by the spring 112 as shown in FIG. Rotate upward about 111. At this time, the load amount regulating member 109 is pressed against the upper surface of the rear end portion of the sheet by the spring 112, but the biasing force (elastic force) of the spring 112 is set to a size that allows the sheet to be fed. It is possible to prevent the occurrence of harmful effects such as sheet jamming and skew feeding during feeding.

  The size capable of feeding the sheet means that the force for regulating the sheet obtained from the relationship between the friction coefficient between the sheet contact surface of the stacking amount regulating member 109 and the sheet and the biasing force of the spring 112 is the pickup roller 103. It means that it is smaller than the force to send out the sheet by. That is, the elastic force of the spring 112 is set so that the force pressing the sheet by the urging force of the spring 112 is always smaller than the force of feeding the sheet by the pickup roller 103.

  In this way, when the stacking amount regulating member 109 is pressed by the rear end portion of the sheet S and rotates upward, the pressure contact force with the rear end portion of the sheet is released, and the intermediate plate 101 rotates upward. Even in this case, the sheet rear end portion is not pressed down by the stacking amount regulating member 109. That is, when the sheet S is pressed by the rear end portion of the sheet S, the stacking amount regulating member 109 is in a state of reducing the pressure contact force with the rear end portion of the sheet. As a result, it is possible to prevent the occurrence of harmful effects such as jamming and skewing due to the sheet trailing edge being pressed, and the sheet can be fed reliably.

  As described above, when the stacking amount regulating member 109 is pressed against the rear end portion of the sheet that rises as the middle plate 101 rotates upward, the stacking amount regulating member 109 is rotated upward to reduce the pressure contact force with the rear end portion of the sheet. In this state, a sheet having a size shorter than that of the middle plate 101 can be reliably fed.

  In the present embodiment, the stacking amount regulating member 109 rotates with the rotation of the middle plate 101 to come into surface contact with the sheet on the middle plate. The load on the sheet during feeding can be reduced.

  Next, a second embodiment of the present invention will be described.

  FIG. 9 is a diagram illustrating the configuration of a sheet feeding cassette that is mounted on the sheet feeding apparatus according to the present embodiment. 9, the same reference numerals as those in FIG. 5 described above indicate the same or corresponding parts. In FIG. 9, 109A is a load amount regulating member, and in this embodiment, this load amount regulating member 109A is provided so as to protrude above the rear end regulating plate 108 and is slidable in the vertical direction. ing.

  In FIG. 9B, reference numeral 108a denotes a guide member protruding from the inner wall surface of the side plate 108b facing the rear end regulating plate 108. Reference numeral 109a denotes a guide groove extending in the vertical direction and formed on the inner wall surface of the side plate 109c provided to face the bottom surface of the contact member 109b that contacts the sheet of the stacking amount regulating member 109A. Then, by engaging the guide member 108a of the rear end regulating plate 108 with the guide groove 109a, the stacking amount regulating member 109A can move in the vertical direction with respect to the rear end regulating plate 108.

  In FIG. 9B, reference numeral 113 denotes a spring which is an elastic member whose upper end is locked to the bottom surface of the contact member 109b of the stacking amount regulating member 109A and whose other end is latched to the rear end regulating plate 108. It is. The load amount regulating member 109A is biased by the spring 113 toward the side pressing the upper surface of the stacked sheets.

  By biasing the stacking amount regulating member 109A by the spring 113 in this way, when the amount of sheets to be stored is too large, the sheets are stored while pushing up the stacking amount regulating member 109A. In other words, if the amount of sheets is too large, sheets cannot be stored unless the stacking amount regulating member 109A is pushed up. Therefore, if sheets cannot be stored unless the stacking amount regulating member 109A is pushed up, the amount of sheets to be stored It can be judged that there are too many.

  Next, an operation of storing a small size sheet and an operation of feeding the sheet in the sheet feeding cassette 100 including the stacking amount regulating member 109A having such a configuration will be described.

  When storing a small-sized sheet shorter than the length of the middle plate 101, first, the side regulating plates 106 and 107 and the rear end regulating plate 108 are aligned according to the size of the sheet, and the sheet is stored in the sheet feeding cassette 100. Thereafter, the paper feed cassette 100 is mounted on the apparatus main body 201. Here, when the rear end regulating plate 108 is set in accordance with such a small-sized sheet, the position of the rear end regulating plate 108 is set to the rotation shaft 102 of the middle plate 101 as shown in FIG. It is on the downstream side of the position.

  After that, when the paper feed cassette 100 is mounted on the apparatus main body 201, as shown in FIG. 10A, the intermediate plate 101 rotates upward about the rotation shaft 102, and thus the intermediate plate 101 is thus formed. Is rotated upward, the sheet S is eventually pressed against the pickup roller 103. Further, when the intermediate plate 101 is raised, the pickup roller 103 is also raised. Thereafter, when the pickup roller 103 is raised to a predetermined position, the intermediate plate 101 is stopped.

  By the way, when the small plate is stacked on the middle plate, if the middle plate 101 rotates upward, the rear end portion of the sheet S also rises together with the middle plate 101 as the middle plate 101 rotates upward. Go. When the sheet S is stored in the sheet feeding cassette 100 until the sheet S comes into contact with the stacking amount regulating member 109A or close to the stacking amount regulating member 109A, the stacking amount is increased by the rear end portion of the sheet S lifted together with the intermediate plate 101. The restricting member 109A is pressed from below.

  Here, when the sheet S is pressed from below by the rear end portion of the sheet S in this way, the stacking amount regulating member 109A slides upward while resisting the bias by the spring 113. At this time, the load amount regulating member 109A is pressed against the upper surface of the rear end portion of the sheet by the spring 113, but the urging force (elastic force) of the spring 113 is set to a size that allows sheet feeding. It is possible to prevent the occurrence of harmful effects such as sheet jamming and skew feeding during sheet feeding.

  The size capable of feeding the sheet means that the pickup roller 103 has a force for regulating the sheet obtained from the relationship between the friction coefficient between the sheet contact surface of the stacking amount regulating member 109A and the sheet and the biasing force of the spring 113. It means that it is smaller than the force to send out the sheet by. That is, the elastic force of the spring 113 is set so that the force pressing the sheet by the urging force of the spring 113 is always smaller than the force of feeding the sheet by the pickup roller 103.

  In this way, the stacking amount regulating member 109A is pressed by the sheet rear end portion and moved upward, so that the pressure contact force with the sheet rear end portion escapes, and the stacking even if the middle plate 101 rotates upward. The rear end portion of the sheet is not pressed down by the amount regulating member 109A. That is, when the sheet S is pressed by the rear end portion of the sheet S, the stacking amount regulating member 109A is in a state of reducing the pressure contact force with the rear end portion of the sheet. As a result, it is possible to prevent the occurrence of harmful effects such as jamming and skewing due to the sheet trailing edge being pressed, and the sheet can be fed reliably.

  In this way, when the stacking amount regulating member 109A is pressed against the rear end portion of the sheet that rises as the middle plate 101 rotates upward, the load amount regulating member 109A is moved upward to reduce the pressure contact force with the rear end portion of the sheet. By setting the state, a sheet having a size shorter than that of the intermediate plate 101 can be reliably fed.

  In the present embodiment, the rear end portion of the sheet can be always pressed down by a certain length by slidingly moving the stacking amount regulating member 109A. Accordingly, for example, when another sheet is fed to the fed sheet, it is possible to prevent the rear end portion of the sheet from being detached from the stacking amount regulating member 109A due to curling or the like.

  Next, a third embodiment of the present invention will be described.

  FIG. 11 is a diagram illustrating the configuration of a sheet feeding cassette that is mounted on the sheet feeding apparatus according to the present embodiment. 11, the same reference numerals as those in FIG. 5 described above indicate the same or corresponding parts. In FIG. 11, 109B is a load amount regulating member. In this embodiment, this load amount regulating member 109B is provided so as to protrude from the upper portion of the rear end regulating plate 108 and is formed by an elastically deformable member. Yes.

  By making the stacking amount regulating member 109B elastically deformable in this way, when the amount of sheets to be stored is too large, the sheets are stored while the stacking amount regulating member 109B is bent upward. That is, if the amount of sheets is too large, the sheets cannot be stored unless the stacking amount regulating member 109B is elastically deformed upward. From this, when the sheets cannot be stored unless the stacking amount regulating member 109B is bent upward, the user can determine that the amount of sheets to be stored is too large.

  Next, an operation for storing a small-sized sheet and an operation for feeding the sheet in the sheet feeding cassette 100 including the stacking amount regulating member 109B having such a configuration will be described.

  When storing a small-sized sheet shorter than the length of the middle plate 101, first, the side regulating plates 106 and 107 and the rear end regulating plate 108 are aligned according to the size of the sheet, and the sheet is stored in the sheet feeding cassette 100. Thereafter, the paper feed cassette 100 is mounted on the apparatus main body 201. Here, when the rear end regulating plate 108 is set in accordance with such a small-sized sheet, the position of the rear end regulating plate 108 is set to the rotation shaft 102 of the middle plate 101 as shown in FIG. It is on the downstream side of the position.

  After that, when the paper feed cassette 100 is mounted on the apparatus main body 201, as shown in FIG. 12A, the intermediate plate 101 rotates upward about the rotation shaft 102, and the intermediate plate 101 is thus formed. Is rotated upward, the sheet S is eventually pressed against the pickup roller 103. Further, when the intermediate plate 101 is raised, the pickup roller 103 is also raised. Thereafter, when the pickup roller 103 is raised to a predetermined position, the intermediate plate 101 is stopped.

  By the way, when the small plate is stacked on the middle plate, if the middle plate 101 rotates upward, the rear end portion of the sheet S also rises together with the middle plate 101 as the middle plate 101 rotates upward. Go. When the sheet S is stored in the sheet feeding cassette 100 until the sheet S comes into contact with the stacking amount regulating member 109B or close to the stacking amount regulating member 109B, the stacking amount is increased by the rear end portion of the sheet S raised together with the intermediate plate 101. The regulating member 109B is pressed from below.

  Here, when the sheet S is pressed from below by the rear end portion of the sheet S, the stacking amount regulating member 109B moves upward while being elastically deformed. At this time, the stacking amount regulating member 109B is pressed against the upper surface of the rear end portion of the sheet by the biasing force due to elastic deformation, and the biasing force (elastic force) of the stacking amount regulating member 109B has a size that allows sheet feeding. Is set. For this reason, it is possible to prevent the occurrence of adverse effects such as sheet jamming and skew feeding during sheet feeding.

  The sheet feedable size refers to the force that regulates the sheet obtained from the relationship between the coefficient of friction between the stacking amount regulating member 109B and the sheet and the elastic force at the time of elastic deformation of the stacking amount regulating member 109B. This means that it is smaller than the sheet feeding force of the roller 103. That is, the material of the stacking amount regulating member 109B is set so that the force for pressing the sheet by the elastic force at the time of deformation of the stacking amount regulating member 109B is always smaller than the force for feeding the sheet by the pickup roller 103.

  As described above, the load amount regulating member 109B is pressed by the rear end portion of the sheet and is elastically deformed upward so that the pressure contact force with the rear end portion of the sheet is released, and the load amount is increased even if the middle plate 101 is rotated upward. The rear end portion of the sheet is not pressed down by the regulating member 109B. That is, when the sheet S is pressed by the rear end portion of the sheet S, the stacking amount regulating member 109B is in a state of reducing the pressure contact force with the rear end portion of the sheet. As a result, it is possible to prevent the occurrence of harmful effects such as jamming and skewing due to the sheet trailing edge being pressed, and the sheet can be fed reliably.

  As described above, in the present embodiment, when the stacking amount regulating member 109B is pressed against the rear end portion of the sheet that rises as the middle plate 101 rotates upward, it is elastically deformed upward, The pressure contact force with the end is reduced. Accordingly, it is possible to reliably feed a sheet having a size shorter than that of the intermediate plate 101.

  Note that the number of parts can be reduced by making the load regulation member 109B elastically deformable as in the present embodiment. Further, the sheet on the rising intermediate plate can be easily copied, and the load on the sheet when the stacking amount regulating member 109B feeds the sheet can be reduced.

1 is a diagram illustrating an overall configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of an image forming unit of the image forming apparatus. FIG. 6 is a diagram illustrating an operation for attaching and detaching a paper feed cassette to and from the image forming apparatus. The figure which shows the structure of the said paper feed cassette. The figure explaining the structure of the load amount control part provided in the rear-end control board of the said paper feed cassette. FIG. 4 is a diagram illustrating a state when feeding a sheet stored in the sheet feeding cassette. The figure which shows the state at the time of accommodating the small sized sheet of the said sheet feeding cassette. FIG. 4 is a diagram illustrating a state when a small size sheet is fed from the sheet feeding cassette. FIG. 6 is a diagram illustrating a configuration of a sheet feeding cassette that is mounted on a sheet feeding apparatus according to a second embodiment of the present invention. FIG. 4 is a diagram illustrating a state when a small size sheet is fed from the sheet feeding cassette. FIG. 10 is a diagram illustrating a configuration of a sheet feeding cassette that is mounted on a sheet feeding apparatus according to a third embodiment of the present invention. FIG. 4 is a diagram illustrating a state when a small size sheet is fed from the sheet feeding cassette. The figure explaining the structure of the conventional sheet feeding apparatus. FIG. 6 is a diagram illustrating a configuration of a sheet feeding cassette that is detachably mounted on a conventional sheet feeding apparatus. The figure explaining the other structure of the said paper feed cassette. The figure which shows the state at the time of accommodating the small sized sheet of the said sheet feeding cassette. FIG. 4 is a diagram illustrating a state when a small size sheet is fed from the sheet feeding cassette.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Paper feed cassette 100a Cassette main body 101 Middle plate 102 Rotating shaft 103 Pickup roller 108 Rear end regulating plate 109 Stack amount regulating member 109A Stack amount regulating member 109B Stack amount regulating member 112 Spring 113 Spring 200 Image forming apparatus 200A Image forming unit 200B Sheet feeding device 201 Image forming apparatus main body S Sheet

Claims (5)

A sheet feeding cassette for storing sheets; and a sheet feeding member disposed above the sheet feeding cassette mounted on the apparatus main body, and pressing the sheets stored in the sheet feeding cassette against the sheet feeding member In the sheet feeding device for feeding by the sheet feeding member,
The paper cassette is
A cassette body for storing sheets;
An intermediate plate that is supported by the cassette body so as to be pivotable in the vertical direction by a pivot shaft, and presses the sheets stacked by pivoting upward against the sheet feeding member;
A rear end regulating member which is provided in the cassette body so as to be movable in the sheet feeding direction and regulates the rear end position of the sheet stored in the cassette body;
A stacking amount regulating member provided on the trailing edge regulating member so as to protrude downstream in the sheet feeding direction and regulating the stacking amount of sheets stored in the cassette body;
A spring that urges the stacking amount regulating member in the opposite direction to the upward rotation so as to return to a position that regulates the stacking amount of sheets when the stacking amount regulating member rotates upward .
The sheet feeding cassette is mounted on the apparatus main body, and the trailing edge regulating member regulates the sheets stacked on the intermediate plate downstream in the sheet feeding direction from the position of the rotation shaft. when the intermediate plate is rotated upward, the loading amount regulating member is provided in the rear end regulating member to move by being pressed by the rear end of the sheet for raising the upper, elastic force of said spring, said A sheet feeding apparatus having a size capable of feeding sheets even when the stacking amount regulating member is rotated upward . The stacking amount regulating member is provided on the trailing end regulating member so as to be pivotable in the vertical direction, and the stacking amount regulating member is pressed by a trailing end portion of the sheet that rises as the middle plate rotates upward. the sheet feeding apparatus according to claim 1, characterized in that the upper rotating from the position for regulating the load of the sheet over and. The stacking amount restricting member is provided on the trailing end restricting member so as to be movable in the vertical direction, and when the stacking amount restricting member is pressed against the rear end portion of the sheet that rises as the middle plate rotates upward, 2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus moves upward from a position where the amount of stacked sheets is regulated against the elastic force of the spring . A sheet feeding cassette for storing sheets; and a sheet feeding member disposed above the sheet feeding cassette mounted on the apparatus main body, and pressing the sheets stored in the sheet feeding cassette against the sheet feeding member In the sheet feeding device for feeding by the sheet feeding member,
The paper cassette is
A cassette body for storing sheets;
An intermediate plate that is supported by the cassette body so as to be pivotable in the vertical direction by a pivot shaft, and presses the sheets stacked by pivoting upward against the sheet feeding member;
A rear end regulating member which is provided in the cassette body so as to be movable in the sheet feeding direction and regulates the rear end position of the sheet stored in the cassette body;
An elastically deformable stacking amount restricting member that protrudes downstream of the trailing end restricting member in a sheet feeding direction and restricts the stacking amount of sheets stored in the cassette body,
The sheet feeding cassette is mounted on the apparatus main body, and the trailing edge regulating member regulates the sheets stacked on the intermediate plate downstream in the sheet feeding direction from the position of the rotation shaft. When the intermediate plate is rotated upward, the stacking amount regulating member is provided on the trailing end regulating member so as to be moved by being pressed by the trailing end portion of the rising sheet, and the elastically deformable stacking amount regulating member. The sheet feeding apparatus is characterized in that the elastic force is set to a size that allows sheet feeding even when the stacking amount regulating member rotates upward. An image forming unit for forming an image on a sheet, the image forming apparatus characterized by comprising a sheet feeding apparatus according to any one of claims 1 to 4 for feeding sheets to the image forming section .

Images