JP4076956B2 - Paper feeder - Google Patents

Description

  The present invention relates to a paper feeding device provided in a printing apparatus, and relates to a paper feeding device that raises a sheet bundle stacked on a lifting tray toward a pickup roller that picks up an upper end sheet of the sheet bundle.

Conventionally, the speed of printing apparatuses has been increased, and the number of printed sheets per unit time has become very large.
Therefore, in general printing apparatuses, as an optional apparatus, a desk-type sheet supply apparatus (sheet supply desk apparatus) provided with a multi-stage sheet supply tray, or about 2,000 to 3,000 sheets of a specific size A large-capacity sheet supply device that can be accommodated is prepared.

  In these sheet feeding apparatuses (sheet feeding apparatuses), a large number of sheets are accommodated in a state of sheet bundles stacked in the vertical direction. Accordingly, since it is difficult to supply sheets from the lower side of the sheet bundle, the upper sheets are taken out one by one by the pickup roller and supplied to the print engine of the printing apparatus.

  In addition, such a sheet feeding device includes a lift tray (lift-up mechanism) that moves the sheet bundle up and down, and a sensor that detects the position of the upper surface of the sheet bundle and the pickup roller. The upper end of the sheet bundle is designed to be controlled to a certain height according to the position of the pickup roller.

Further, when such a sheet feeding device is used, the print quality is greatly influenced by the positional accuracy of the sheet (sheet serving as the upper end of the sheet bundle; upper end sheet) taken out by the pickup roller.
In many cases, the sheet used for printing is of a prescribed size. However, even a sheet of a prescribed size has variations in dimensions. Further, the dimensions of the sheet also change depending on changes in environmental conditions (particularly humidity).
For this reason, the conventional sheet feeding apparatus includes an alignment mechanism for arranging the upper end sheet at the reference position.

Here, the reference position of the upper end sheet is an appropriate position of the upper end sheet to be taken out by the pickup roller (if the upper end sheet is arranged at that position, the upper end sheet can be appropriately conveyed, and printing is appropriately performed on this sheet. It is a position that can be done).
That is, when the upper end sheet that is shifted from the reference position is taken out by the pickup roller and conveyed toward the printing apparatus, the printed image on the sheet may be distorted or shifted.

In order to arrange the upper end sheet at such a reference position, for example, an alignment mechanism described in Patent Document 1 includes a fixed reference wall surface and a leaf spring that presses the upper portion of the sheet bundle against the reference member. Have.
And it is designed to urge the other end of the sheet toward the reference member by pushing one end (edge) of the sheet with a leaf spring.

That is, in this alignment mechanism, the leaf spring is disposed at a position facing the reference wall surface with the sheet bundle interposed therebetween. Further, the leaf spring is inclined so as to narrow the distance from the reference wall surface as it goes upward.
Therefore, in this configuration, the sheet on the lifting tray is pushed by the leaf spring as it moves up and approaches the reference wall surface. And when it becomes an upper end sheet | seat, it is made to contact | abut to a reference | standard wall surface. Thereby, it is possible to appropriately adjust the position of the upper end sheet.
Patent Publication No. 2906778 (issue date; June 21, 1999)

Here, in the sheet feeding apparatus as described above, when a new sheet is replenished in the apparatus, the new sheet is stacked on the upper part of the sheet bundle (on the upper end sheet).
Therefore, at this time, there is a problem that the user touches the leaf spring located in the vicinity of the upper end sheet and the leaf spring is easily deformed.
Further, since the sheet is raised while pushing the edge of the sheet with a leaf spring (rubbed against the leaf spring), there is also a drawback that the sheet is easily deformed.

  The present invention has been made in view of the conventional problems as described above. An object of the present invention is to provide a sheet feeding device capable of preventing the deformation of the sheet due to the lifting of the lifting tray.

In order to achieve the above object, a sheet feeding device (this sheet feeding device) according to the present invention raises a sheet bundle stacked on an elevating tray toward a pickup unit that takes out the upper end sheet of the sheet bundle. The upper end sheet is formed at a position facing the reference wall surface across the upper end sheet so as to narrow the distance from the reference wall surface along the rising direction of the upper end sheet, and is in contact with the end of the rising upper end sheet. An alignment member that aligns the upper end sheet so that one side of the sheet abuts against the reference wall surface is provided, and the alignment member includes a rotating member that rotates under the force of the rising upper end sheet.
The paper feeding apparatus is provided in a printing apparatus that prints an image on a sheet (printing paper) such as a printer, a facsimile machine, or a copying machine.
The paper feeding device supplies a sheet used for printing to such a printing device.

  In addition, the sheet feeding apparatus accommodates a plurality of sheets in a state of a sheet bundle that is stacked in the vertical direction (vertical direction). A sheet positioned at the uppermost end (upper end sheet; uppermost sheet) of the sheet bundle is taken out by a pickup unit positioned at the upper part of the sheet bundle and supplied to the printing apparatus.

The pick-up unit takes out a sheet in contact with itself.
Therefore, in the sheet feeding device, the sheet bundle is stacked on an elevating tray that can be moved up and down with respect to the pickup unit (the height of the upper end sheet can be adjusted).
At the time of printing, the sheet bundle stacked on the lifting tray is raised toward the pickup unit together with the lifting tray. Thereby, the upper end sheet of the sheet bundle can be brought into contact with the pickup unit.

In a paper feeding device such as this paper feeding device, it is preferable that the position of the upper end sheet taken out by the pickup unit is accurately arranged at a predetermined reference position.
Here, the reference position of the upper end sheet is an appropriate position of the upper end sheet to be picked up (if the upper end sheet is arranged at that position, the upper end sheet can be appropriately conveyed and printing can be appropriately performed on this sheet. Like this).

Therefore, the sheet feeding device includes a reference wall surface and an alignment member in order to place the upper end sheet at the reference position.
Here, the reference wall surface is a wall surface designed so that the upper end sheet can be arranged at the reference position by bringing one side of the upper end sheet into contact with the wall surface.

As such a reference wall surface, for example, a wall surface parallel to the direction in which the sheet is taken out by the pickup unit (the take-out direction) can be mentioned.
When one side of the upper sheet is brought into contact with the wall surface, the pickup unit takes out the upper sheet toward the center of the conveyance path to the printing apparatus with the two sides parallel to the take-out direction. It is preferable that the wall surface be capable of.

  The alignment member aligns (adjusts the position) of the upper end sheet (on the lifting tray) before being taken out by the pickup unit so that one side thereof is in contact with the reference wall surface.

Such an aligning member is disposed at a position facing the reference wall surface with the upper end sheet (sheet bundle) interposed therebetween, and is configured from a member that applies a force in contact with the end of the rising upper end sheet.
That is, this member contacts the side (contact side) facing the side (reference side) close to the reference wall surface in the upper end sheet, and by pushing this side toward the reference wall side, the position of the upper end sheet is moved (shifted). ), And is designed so that the reference side of the upper end sheet contacts the reference wall surface.

  Here, the force that pushes the upper end sheet of the alignment member toward the reference wall surface is generated by the movement of the upper end sheet (sheet bundle).

That is, the alignment member is formed at the end of the rising upper end sheet on the path so as to narrow the distance from the reference wall surface as it approaches the pickup section from the lower side (along the rising direction (path) of the upper end sheet). ing.
Therefore, the contact portion of the alignment member with the upper end sheet is slightly inclined so as to cover the upper end sheet.
Therefore, when the rising upper end sheet (sheet bundle) comes into contact with (acts on) the aligning member, the upper end sheet pushes the aligning member in the horizontal direction (horizontal force) and pushes the aligning member upward (upward force). ) And work.
Then, the upper end sheet moves (displaces) toward the reference wall surface under the reaction of the horizontal force that pushes the alignment member in the horizontal direction.

In particular, in the present paper feeding device, the alignment member is constituted by a rotating member that rotates in response to the force (upward force) of the rising upper end sheet.
In other words, the sheet feeding device is designed to absorb the upward force by rotating the rotating member (alignment member) by the upward force received from the upper end sheet. That is, the rotating member functions to relieve the downward pressing force received by the upper end sheet.
Therefore, in the sheet feeding device, it is possible to eliminate the reaction acting on the sheet from the aligning member with respect to the upward force of the upper end sheet acting on the aligning member.
For this reason, in this sheet feeding device, it is possible to reliably prevent the upper end sheet from being deformed (bent) by the reaction of the upward force.

In addition, as described in the background art, when the alignment member is configured by a leaf spring, the end portion of the rising upper end sheet is rubbed and deformed by the leaf spring. This is equivalent to the fact that there is no change in the leaf spring due to the upward force from the top sheet (the leaf spring does not deform or move), so that the reaction of the upward force occurs and the edge of the top sheet is deformed. It is.
Therefore, in this paper feeding apparatus, the alignment member (rotating member) rotates as the upper end sheet is raised, so that the contact side of the upper end sheet (contact point with the alignment member) is not rubbed by the alignment member, and the upper end sheet is deformed. It can also be expressed as not.

  In this paper feeding device, since the alignment member is composed of a rotating member, even if a relatively strong external force is received from something other than the sheet (such as a user's hand), this force can be absorbed by rotation. . Therefore, deformation due to external force is less likely to occur than an alignment member made of a leaf spring.

Moreover, it is preferable that the rotating shaft of the rotating member that is the alignment member of the sheet feeding device extends substantially parallel to the reference wall surface.
That is, it is preferable that the rotation shaft of the rotating member is parallel to the reference wall surface so that one side of the sheet can come into contact with the reference wall surface when the sheet contacts the rotating member.

  The rotating member as described above can be easily configured from a driven belt or a driven roller disposed at a position facing the reference wall surface with the upper end sheet interposed therebetween, for example.

Further, when the rotating member is constituted by a driven roller, the end portion of the upper end sheet comes into contact with the surface of the roller.
Here, an elastic member may be disposed on the surface of the driven roller, and the elastic member may be configured to contact the upper end sheet.

  Such an elastic member is elastically deformed when it comes into contact with the upper end sheet. Therefore, the impact (reaction) on the upper end sheet that occurs when the upper end sheet comes into contact with the rotating member can be further alleviated.

Furthermore, by adjusting the softness (ease of deformation) of the elastic member, it is possible to adjust the force (horizontal force reaction) that pushes the upper end sheet in the horizontal direction.
That is, this reaction can be weakened by configuring the elastic member with a soft material. Therefore, it is possible to prevent the upper end sheet from being deformed due to this force being too strong, and further, it is possible to avoid the occurrence of jam due to the deformation of the sheet.

  Such an elastic member can be formed of, for example, a foamable material (such as a sponge). If an elastic member is comprised with such a material, the force (reaction) which pushes an upper end sheet | seat in a horizontal direction can be made small. Therefore, it is possible to reliably prevent the upper end sheet from being deformed or jammed due to this force.

  Further, such an elastic member may be designed to be formed not on the entire surface of the driven roller but only on a part thereof. Even in this configuration, the force (reaction) for pushing the upper end sheet in the horizontal direction can be reduced.

Moreover, it is preferable to form a protective layer for protecting the elastic member on the surface of such an elastic member. Thereby, it can prevent that an elastic member is damaged by the edge part (edge) of an upper end sheet | seat.
The protective layer is preferably made of a smooth material. Thereby, the edge of the upper end sheet can be easily slipped on the surface of the rotating member. For this reason, deformation of the upper end sheet due to friction between the protective layer and the upper end sheet can be avoided.

Moreover, it is preferable that the driven roller forming the rotating member is formed at an appropriate position. For example, it is preferable to arrange the center of the driven roller at a position higher than the upper end sheet taken out by the pickup unit.
In this configuration, the upper end sheet once in contact with the rotating member can be pressed horizontally against the reference wall surface until it is taken out by the pickup unit (the upper end sheet is pressed against the reference wall surface until it is taken out. Can be).

  As described above, the sheet feeding device (the present sheet feeding device) according to the present invention is a sheet feeding device that raises a sheet bundle stacked on an elevating tray toward a pickup unit that takes out the upper end sheet of the sheet bundle, It is formed at the position facing the reference wall surface across the upper end sheet so as to narrow the distance from the reference wall surface along the ascending direction of the upper end sheet. An alignment member that aligns the upper end sheet so as to be in contact with the reference wall surface is provided, and the alignment member includes a rotating member that rotates by receiving the force of the rising upper end sheet.

In the sheet feeding device, the alignment member is composed of a rotating member that rotates by receiving the force (upward force) of the rising upper sheet.
In other words, the sheet feeding device is designed to absorb the upward force by rotating the rotating member (alignment member) by the upward force received from the upper end sheet.
Therefore, in the sheet feeding device, it is possible to eliminate the reaction acting on the sheet from the aligning member with respect to the upward force of the upper end sheet acting on the aligning member.
For this reason, in this sheet feeding device, it is possible to reliably prevent the upper end sheet from being deformed (bent) by the reaction of the upward force.

  In this paper feeding device, since the alignment member is composed of a rotating member, even if a relatively strong external force is received from something other than the sheet (such as a user's hand), this force can be absorbed by rotation. . Therefore, deformation due to external force is less likely to occur than an alignment member made of a leaf spring.

An embodiment of the present invention will be described.
The printing apparatus (this printing apparatus) according to the present embodiment is a printer that prints image data input from the outside on a printing paper (sheet) and outputs the same.

FIG. 1 is an explanatory diagram illustrating a configuration of the printing apparatus.
As shown in this figure, the printing apparatus includes a printer unit 2, a paper feeding unit unit 3 disposed below the printer unit 2, a paper feeding unit 20 installed on the right side of the paper feeding unit unit 3, and a printer unit 2. And a discharge tray 26 formed thereon.

The printer unit 2 is for printing an image on a sheet based on image data input from the outside.
As shown in FIG. 1, the printer unit 2 includes a photosensitive drum 4, a charging unit 5, an optical scanning unit 6, a developing unit 7, a transfer unit 8, and a cleaning unit disposed around the photosensitive drum 4. An electrophotographic process unit including the unit 9 and the fixing unit 27 is arranged at substantially the center.

The photoreceptor drum 4 is a drum-shaped photoreceptor having a photoreceptor material on the surface.
The charging unit 5 uniformly charges the surface of the photosensitive drum 4.
The optical scanning unit 6 scans the uniformly charged photosensitive drum 4 with a laser beam modulated according to image data, and writes an electrostatic latent image on the photosensitive drum 4.

The developing unit 7 develops (develops) the electrostatic latent image written by the optical scanning unit 6 with a developer (toner or the like) to generate a developer image.
The transfer unit 8 transfers the developer image on the photosensitive drum 4 to a sheet.
The fixing unit 27 fixes the image on the sheet by thermocompression bonding the sheet on which the image (developer image) is transferred.

The cleaning unit 9 removes the developer remaining on the photosensitive drum 4 after the transfer of the developer image to the sheet. As a result, a new latent image can be formed on the photosensitive drum 4.
The residual developer removed by the cleaning unit 9 is collected in the developer supply unit 10 of the developing unit 7 and recycled.

  The discharge tray 26 is a tray for discharging sheets printed by the printer unit 2.

  The sheet feeding unit 3 has a function of accumulating sheets used for printing and supplying the sheets to the printer unit 2 at the time of printing.

  As shown in FIG. 1, the paper feed unit 3 includes a plurality of paper feed devices including paper feed trays 11 to 14 and a manual paper feed unit 18, and separates and stores various sheets having different sizes and materials. Designed to be able to.

The paper feed trays 11 to 14 are paper feed devices disposed inside the frame 17 that forms the paper feed unit unit 3.
The paper feed tray 11 and the paper feed tray 12 are arranged near each other in the vicinity of the upper portion of the paper feed unit unit 3.
The paper feed tray 13 is arranged below the paper feed trays 11 and 12, and the paper feed tray 14 is arranged below the paper feed tray 13.

Further, the capacity of the paper feed tray 13 and that of the paper feed tray 14 are approximately the same. Further, the capacity of the paper feed trays 11 and 12 is set larger than that of the paper feed trays 13 and 14.
Further, the replenishment of sheets to each of the paper feed trays 11 to 14 is performed by pulling out the paper feed trays 11 to 14 in the front side direction (direction perpendicular to the paper surface) of the printing apparatus.

  The manual paper feed unit 18 is a paper feeder provided with a manual paper feed tray 19 on which a relatively small amount of sheets can be set directly (easily) from the outside.

As shown in FIG. 1, the paper feeding unit 3 includes a first transport path 15, a second transport path 16, a third transport path 21, and a fourth transport path 24.
The first transport path 15 is a transport path extending in the vertical direction along the frame 17 of the paper feed unit unit 3, and transports the sheets on the paper feed trays 11, 13, and 14 toward the printer unit 2. .

On the other hand, the second conveyance path 16 is a conveyance path extending in a direction (horizontal direction) perpendicular to the frame 17, and conveys the sheets on the paper feed tray 12 toward the printer unit 2.
The second conveyance path 16 also has a function of conveying the sheets of the manual sheet feeding unit 18 and the sheet feeding unit 20 supplied via the third conveyance path 21 and the fourth conveyance path 24 to the printer unit 2. is doing.

The third conveyance path 21 is a conveyance path for conveying the sheet of the manual sheet feeding unit 18 to the second conveyance path 16.
The fourth conveyance path 24 is a conveyance path that conveys a sheet of a paper feeding unit 20 described later to the second conveyance path 16.

  The paper feeding unit 20 is an optional device of the printing apparatus, and is a paper feeding device having a larger capacity than the paper feeding trays 11 to 14 and 19. The paper feeding unit 20 will be described in detail later.

The printing apparatus also includes a control unit 31 that controls all operations of the printing apparatus.
FIG. 2 is a block diagram illustrating a control mechanism of the printing apparatus.
As shown in this figure, the printing apparatus includes an operation unit 32 in addition to the printer unit 2, the paper feed unit unit 3, the paper feed unit 20, and the discharge tray 26. It is the structure to control.
The operation unit 32 receives user input instructions and transmits them to the control unit 31. The operation unit 32 also has a function of displaying a predetermined message from the control unit 31 to the user.

  In the printing apparatus, when image data is input from the outside, the control unit 31 selects one sheet feeding apparatus from the sheet feeding trays 11 to 14, the manual sheet feeding unit 18, or the sheet feeding unit 20 of the printer unit 2. To do. Thereafter, the control unit 31 conveys the selected sheet of the sheet feeding device between the photosensitive drum 4 of the printer unit 2 and the transfer unit 8 using a conveyance roller.

  Further, the control unit 31 controls each member on the printer unit 2 based on the image data, and forms a developer material image on the photosensitive drum 4. Then, the developer image is set to be transferred (printed) to the sheet and discharged to the discharge tray 26.

Next, the paper feeding unit 20 that is a characteristic configuration of the printing apparatus will be described in detail.
As shown in FIG. 1, the paper feed unit 20 includes a lift tray unit 40 and a pickup mechanism 41.

The lift tray section 40 includes a lift motor 42, a lift tray 43, and a pulley 44 shown in FIG.
The elevating tray 43 is a paper feed tray for storing stacked sheets (sheet bundles).
The lift motor 42 and the pulley 44 are mechanisms for moving the lifting tray 43 up and down.

  Then, the controller 31 controls the position of the lifting tray 43 by the lift motor 42 during printing so that the upper end of the sheet bundle on the lifting tray 43 is in contact with a pickup roller (described later) of the pickup mechanism 41. Is set to

The pickup mechanism 41 feeds the sheet on the lifting tray 43 into the fourth transport path 24 of the paper feed unit unit 3.
FIG. 3 is an explanatory diagram showing the configuration of the pickup mechanism 41.
As shown in this figure, the pickup mechanism 41 includes a conveyance roller pair 51, a separation roller 52, a paper feed roller 53, a pickup roller 54, a sheet conveyance sensor 55, a sheet level detector 56, and an upper limit detector 57.

  The pickup roller (pickup unit) 54 is disposed so as to contact the upper end of the sheets stacked on the lifting tray 43. Then, by rotating in the direction A in FIG. 3, the sheet in contact with itself (the sheet at the upper end of the sheet bundle) is taken out from the lifting tray 43.

  The paper feed roller 53 is connected to the pickup roller 54 by a belt, and rotates in the A direction under the control of the control unit 31. Thereby, the pickup roller 54 is rotationally driven in the A direction.

  The separation roller 52 is provided to face the paper feed roller 53. The separation roller 52 separates the sheets taken out by the pickup roller 54 one by one.

That is, the sheet taken out by the pickup roller 54 is conveyed between the rollers 52 and 53.
When only one sheet is picked up by the pickup roller 54, the separation roller 52 receives the driving force of the paper feed roller 53 and rotates in the B direction. As a result, the sheet is conveyed to the conveying roller pair 51 side.

On the other hand, when two or more sheets are conveyed from the pickup roller 54, the separation roller 52 senses a load variation due to a change in the number of sheets and transmits it to the control unit 31. The separation roller 52 rotates in the A direction under the control of the control unit 31.
As a result, the upper sheet comes into contact with the sheet feeding roller 53 rotating in the A direction and is conveyed to the conveying roller pair 51 side. On the other hand, the lower sheet contacts the separation roller 52 that rotates in the A direction, and is returned to the lifting tray 43 side.
Note that the controller 31 may perform control so as to stop the rotation of the separation roller 52 when there is a load fluctuation as described above. Even in this configuration, only the upper sheet can be conveyed to the conveying roller pair 51 side.

The conveyance roller pair 51 is a roller pair for applying a conveyance force toward the fourth conveyance path 24 to the sheet that has passed between the rollers 52 and 53 under the control of the control unit 31.
The sheet conveyance sensor 55 is a detector for detecting that the sheet has passed through the conveyance roller pair 51 and transmitting the detection result to the control unit 31.

  The pickup roller 54 is designed so that its position changes according to the height (sheet height) of the upper end of the sheet bundle stacked on the lifting tray 43. This is for detecting the sheet height in the lifting tray 43.

  That is, in this printing apparatus, it is preferable to keep the sheet height at a predetermined value. Therefore, in the present printing apparatus, the sheet height is detected based on the position of the pickup roller 54 that is in contact with the upper end portion of the sheet.

  That is, the sheet level detector 56 shown in FIG. 3 detects the sheet height by detecting the position of the pickup roller 54. And the control part 31 is set so that the height of the raising / lowering tray 43 may be controlled according to the detected sheet height.

Further, the upper limit detector 57 detects that when the position of the pickup roller 54 exceeds the upper limit, and transmits it to the control unit 31.
That is, when a trouble such as a failure of the sheet level detector 56 or the lift motor 42 (or its control system) occurs, the sheet height (position of the pickup roller 54) may rise above a predetermined value.

Therefore, in this printing apparatus, when the position of the pickup roller 54 exceeds the upper limit value, this is detected by the upper limit detector 57 and transmitted to the control unit 31.
In response, the control unit 31 determines that the above trouble has occurred. Then, the control unit 31 gives a warning to the user that a trouble has occurred via the operation unit 32.

  Further, the sheet feeding unit 20 is provided with an alignment mechanism for arranging an upper end sheet (a sheet serving as the upper end of the sheet bundle) taken out by the pickup roller 54 at an appropriate position.

Here, the alignment mechanism (main alignment mechanism) in the paper feeding unit 20 will be described.
FIG. 4 is a front view showing the configuration of the alignment mechanism, and FIG. 6 is a top view of the same.
As shown in these drawings, the alignment mechanism includes a reference guide member 61, a counter guide member 62, an alignment roller 63, a rear end guide member 64, and a front end guide member 65.

  The reference guide member 61 is a wall surface formed in parallel with the side surface on the front surface side (front side in FIG. 1) of the paper feeding unit 20. Further, the opposing guide member 62 is a wall surface formed in parallel to the side surface facing the reference guide member 61 (the side surface on the back surface side of the sheet feeding unit 20) with the sheet bundle interposed therebetween.

  Further, the rear end guide member 64 is a wall surface formed on the upstream side in the paper feeding direction (the B direction shown in FIGS. 1 and 6) in the paper feeding unit 20. Further, the tip guide member 65 is a wall surface formed on the downstream side as well.

  And the guide members 61-64 have the function to support the edge part (four sides) of the sheet | seat which goes up and down with the raising / lowering tray 43 so that it may not shift | deviate largely from a tray (and another sheet | seat). .

The reference guide member 61 has a function as a guide (reference wall surface) for determining the reference position of the upper end sheet.
Here, the reference position of the upper end sheet is an appropriate position of the upper end sheet taken out by the pickup roller 54 (if the upper end sheet is arranged at that position, the upper end sheet can be appropriately conveyed and printed on this sheet appropriately. It is a position that can be performed).

In other words, the reference guide member 61 is a wall surface parallel to the direction in which the sheet is taken out by the pickup roller 54 (the taking-out direction).
When the upper end sheet is in contact (contact) with the reference guide member 61 on one side (reference side; a side close to the reference guide member 61), the pickup roller 54 takes out the upper side sheet in the direction of taking out. In a parallel state, it can be taken out toward the center of the fourth transport path 24.
Thus, the reference position of the upper end sheet in the printing apparatus is a position where one side (reference side) of the upper end sheet is brought into contact with the reference guide member 61.

  The alignment roller 63 (alignment member, rotation member, driven roller) has a plurality of sheets (upper sheets (including the upper sheet)) positioned above the opposed guide member 62 and above the sheet bundle stacked on the lifting tray 43. This is a driven roller (a roller having no drive mechanism) arranged so as to abut against the end portion (the end portion on the opposite guide member 62 side).

FIG. 5 is an explanatory diagram showing the configuration of the alignment roller 63.
As shown in this figure, the alignment roller 63 has a configuration in which rod portions 72 and elastic members 73 are provided at both ends of the support shaft 71.

The support shaft 71 is an elongated cylinder whose both ends are supported by a housing frame (not shown) of the paper feed unit 20, and is a rotation shaft of the alignment roller 63. The support shaft 71 extends substantially parallel to the reference guide member 61 and substantially parallel to the sheet surface of the upper end sheet.
The rod portion 72 is a cylindrical member having a hole in the center, and serves as a base for attaching the elastic member 73. The rod portion 72 is fixed to the support shaft 71 so as to be concentric with the support shaft 71 (so that the rotation center of the support shaft 71 passes through the center of the rod portion 72).

The elastic member 73 has a disk shape (thick ring shape) made of an elastic material having a hole in the center, and the support shaft with respect to the outside of the rod portion 72 (the end side of the support shaft 71). It is fixed so as to be concentric with 71.
The diameter of the elastic member 73 is designed to be larger than that of the rod portion 72. Therefore, as shown in FIG. 5, the outer edge portion of the elastic member 73 protrudes from the rod portion 72.

The alignment roller 63 is designed to rotate as a whole according to an external force with the support shaft 71 as a rotation axis.
Further, the alignment roller 63 is disposed at a position where only the outer edge portion of the elastic member 73 protruding from the rod portion 72 contacts the end portion of the upper sheet.
Further, as shown in FIG. 4, the center (support shaft 71) of the alignment roller 63 is arranged at a position higher than the upper end sheet taken out by the pickup roller 54.

Next, the alignment operation by this alignment mechanism will be described.
7A to 7C are explanatory views showing the alignment operation of the alignment mechanism.
In the present printing apparatus, when a new sheet is replenished to the paper feeding unit 20, the control unit 31 temporarily lowers the lifting tray 43 to the lowest end.
At this time, the upper end sheet P is not in contact with the alignment roller 63 as shown in FIG.

After replenishing the sheet, the control unit 31 raises the lifting tray 43 in order to bring the upper end sheet P into contact with the pickup roller 54 (raises the lifting tray 43 in the E direction).
At this time, as shown in FIG. 7B, the upper sheet including the upper end sheet P contacts the elastic member 73 of the alignment roller 63.

Here, the elastic member 73 has a disk shape, and is in a state of protruding to the end portion on the path of the rising sheet bundle (upper end sheet P).
Accordingly, the elastic member 73 is disposed at the end of the ascending sheet bundle on the path so as to narrow the distance from the reference guide member 61 along the ascending direction (path) of the sheet bundle (the elastic member 73). And has a contour that covers the top sheet).

Therefore, when the end portion (contact side; side facing the reference side) of the rising upper sheet contacts (acts) the elastic member 73, a force (horizontal force) that pushes the elastic member 73 in the horizontal direction from the upper sheet. A force (upward force) that pushes the alignment member upward acts, and the elastic member 73 is elastically deformed.
Then, the contact side of the upper sheet receives a reaction (elastic force; force to return deformation) of a horizontal force that pushes the elastic member 73 in the horizontal direction. As a result, the upper sheet moves toward the reference guide member 61. That is, the upper sheet shifts (slides) from the original stacking position (position before contacting the elastic member 73) in the direction D (direction toward the reference guide member 61) shown in FIG. 7B.
In addition, the entire alignment roller 63 including the elastic member 73 rotates in the C direction in response to the upward force from the upper sheet.

Thereafter, the controller 31 stops the lifting of the lifting tray 43 at the stage where the upper end sheet P is brought into contact with the pickup roller 54.
At this time, as shown in FIG.7 (c), the upper sheet | seat will be in the state which shifted | deviated largely to D direction by the elastic force (reaction of a horizontal force) received from the elastic member 73. FIG. Further, the deviation (and the elastic force in the horizontal direction (D direction) received from the elastic member 73) becomes larger as the sheet is closer to the upper end sheet P.
Thereby, the upper end sheet P (the reference side of the upper end sheet P) can be brought into contact with the reference guide member 61 at a position facing the alignment roller 63 with the sheet bundle interposed therebetween.

In addition, after the upper end sheet is taken out by the pickup roller 54, the control unit 31 slightly raises the lifting tray 43 to a position where the new upper end sheet (the uppermost sheet of the sheet bundle) is brought into contact with the pickup roller 54. Raise.
As a result, the new upper end sheet also slightly receives the elastic force received from the elastic member 73 of the alignment roller 63 and shifts to a state in which it is in contact with the reference guide member 61.

As described above, the sheet feeding unit 20 in the sheet feeding apparatus includes the reference guide member 61 and the alignment roller 63 in order to place the upper end sheet at the reference position.
Here, the reference guide member 61 is a reference wall surface designed so that the upper end sheet can be disposed at the reference position by bringing one end of the upper end sheet into contact with the reference guide member 61.
The alignment roller 63 contacts the side (contact side) facing the side (reference side) close to the reference guide member 61 in the upper end sheet, and moves the position of the upper end sheet by pushing this side toward the reference guide member 61 side. The reference side of the upper end sheet is designed to come into contact with the reference guide member 61.

In particular, in the sheet feeding unit 20, the alignment roller 63 is set to rotate by receiving the force (upward force) of the rising upper sheet (upper sheet).
That is, the sheet feeding unit 20 is designed to absorb the upward force by rotating the alignment roller 63 by the upward force received from the upper end sheet.
Therefore, in the sheet feeding unit 20, it is possible to eliminate the reaction acting on the upper end sheet from the alignment roller 63 with respect to the upward force of the upper end sheet acting on the alignment roller 63.
For this reason, in the paper feeding unit 20, it is possible to reliably prevent the upper end sheet from being deformed (folded or the like) due to the reaction of the upward force.

  It should be noted that, in the sheet feeding unit 20, the alignment roller 63 rotates as the upper end sheet is raised, so that the contact edge of the upper end sheet (contact point with the alignment roller 63) is not rubbed against the alignment roller 63. It is also possible to express that “the upper end sheet is not deformed”.

  Further, in the sheet feeding unit 20, even if a relatively strong external force is received by the alignment roller 63 from something other than the sheet (such as a user's hand), this force can be absorbed by rotating. Therefore, the deformation due to the external force is less likely to occur compared to the leaf spring.

Further, the alignment roller 63 is configured such that an elastic member 73 is disposed on the surface of the rod portion 72 and the elastic member 73 is in contact with the upper end sheet.
As shown in FIGS. 7A to 7C, such an elastic member 73 is elastically deformed when it comes into contact with the upper end sheet. Therefore, the impact on the upper end sheet that occurs when the upper end sheet comes into contact with the alignment roller 63 can be reduced.

  Furthermore, by adjusting the softness (ease of deformation) of the elastic member 73, it is possible to adjust the force (reaction) that pushes the upper end sheet in the horizontal direction. That is, this reaction can be weakened by configuring the elastic member 73 with a soft material. Therefore, it is possible to prevent the upper end sheet from being deformed due to this force being too strong, and further, it is possible to avoid the occurrence of jam due to the deformation of the sheet.

  Further, in the alignment roller 63, the elastic member 73 is formed not on the entire surface of the rod portion 72 but only on a part thereof. Therefore, the force (reaction) for pushing the upper end sheet in the horizontal direction can be reduced.

Further, the alignment roller 63 is configured such that the center thereof is arranged at a position higher than the upper end sheet at the position where the alignment roller 63 is taken out by the pickup roller 54.
Therefore, in the alignment roller 63, the upper end sheet once in contact with the elastic member 73 can be pushed in the horizontal direction with respect to the reference guide member 61 until the upper end sheet is taken out by the pickup roller 54 (the upper end sheet is It can be pressed against the reference guide member 61 until it is taken out).

  In the present embodiment, the upper end sheet in the elevating tray 43 is in contact with the reference guide member 61. Of course, the upper end sheet and a plurality of sheets in the vicinity thereof are in contact with the reference guide member 61. It may be in a state (at least the upper end sheet only needs to be in contact with the reference guide member 61).

Further, in the present embodiment, the rod portion 72 of the alignment roller 63 is fixed to the support shaft 71, and the alignment roller 63 is rotated as a whole according to external force with the support shaft 71 as a rotation axis.
However, the configuration is not limited to this, and the support shaft 71 may not be rotated (fixed). In this case, it is preferable that the rod portion 72 and the elastic member 73 are rotatably attached to the support shaft 71, and only the rod portion 72 and the elastic member 73 are rotated by an external force.

Moreover, it is preferable to form the rod part 72 with the resin material (POM (polyacetal resin etc.)) excellent in slipperiness.
Moreover, although the rod part 72 may be formed using a metal material, the direction using a resin material is excellent in mass productivity.

  The elastic member 73 can be formed of, for example, a foamable material (urethane, sponge, etc.). If the elastic member 73 is made of such a material, the force (reaction) for pushing the upper end sheet in the horizontal direction can be reduced. Therefore, it is possible to reliably prevent the upper end sheet from being deformed or jammed due to this force.

Further, it is preferable to provide a protective layer on the outer peripheral surface of the elastic member 73 in order to prevent the elastic member 73 from being damaged (cracked) by the edge of the sheet.
The protective layer can be made of, for example, PET (polyethylene terephthalate) or PTFE (polytetrafluoroethylene). Further, the film thickness of the protective layer is preferably 50 μm or less. Thereby, the protective layer can be easily deformed partially by the force received from the sheet.

The protective layer is preferably made of a smooth material.
Thereby, the edge of an upper end sheet | seat can be slippery on the surface of a protective layer. For this reason, deformation of the upper end sheet due to friction between the protective layer and the upper end sheet can be avoided.

In the present embodiment, the elastic member 73 has a disk shape made of an elastic material and is attached to the outside of the rod portion 72.
However, the shape of the elastic member 73 is not limited to this.

For example, as shown in FIG. 8A, the elastic member 73 may be formed into a thin ring shape that fits into the outer peripheral portion of the rod portion 72.
In the configuration shown in FIGS. 8A to 8C, the protective layer 74 described above is disposed on the surface of the elastic member 73.

  Further, as shown in FIG. 8B, a projecting portion 72a may be provided at the tip of the rod portion 72, and a ring-shaped elastic member 73 may be fitted into the outer peripheral portion of the projecting portion 72a. . In this case, the elastic member 73 can be made thicker (in the radial direction thicker) than the configuration shown in FIG.

Further, as shown in FIG. 8C, a ring-shaped core member 73a made of resin is fitted into the center hole of the ring-shaped elastic member 73, and these are attached to the outside of the rod portion 72, so that the core member 73a The center hole may be penetrated by the support shaft 71.
8B and 8C, it is preferable that the diameter of the elastic member 73 is larger than that of the rod portion 72.
Further, in the configuration of FIG. 8C, the rod portion 72 may not be provided, and the elastic member 73 (core member 73a) may be simply attached to the support shaft 71.

In the present embodiment, the rod portion 72 to which the elastic member 73 is attached has a cylindrical shape.
However, the shape of the rod portion 72 is not limited to this, and the rod portion 72 may have any shape as long as the elastic member 73 is attached and the rod portion 72 can rotate together with the support shaft 71 (or can rotate around the support shaft 71). Also good.

Further, the alignment roller 63 may be configured not to include the elastic member 73. In this case, the upper end sheet comes into contact with the rod portion 72 of the alignment roller 63 and moves (displaces) to the reference guide member 61 side by the force received from the rod portion 72.
Even in this configuration, the upward force received from the upper end sheet is received by the rod portion 72, and the alignment roller 63 rotates, whereby the reaction of the upward force can be suppressed. Therefore, deformation of the upper end sheet can be prevented.

  Further, in the present embodiment, the support shaft 71 of the alignment roller 63 that is the alignment roller 63 of the paper feeding unit 20 extends substantially parallel to the reference guide member 61. Here, the support shaft 71 of the aligning roller 63 has a reference guide member 61 to such an extent that one side (reference side) of the upper end sheet is brought into contact with the reference guide member 61 when the upper end sheet contacts the aligning roller 63. Are preferably parallel to each other. Further, the support shaft 71 may be completely parallel to the reference guide member 61.

Further, in the present embodiment, as the elevating tray 43 is raised, a plurality of sheets (including the upper sheet) positioned at the upper part of the sheet bundle are in contact with the elastic member 73 of the alignment roller 63. Here, the number of sheets in contact with the elastic member 73 varies depending on the thickness of the sheet and the diameter of the elastic member 73.
The sheet feeding device may be designed so that at least the upper end sheet is brought into contact with the elastic member 73, and thereby the reference side of the upper end sheet is brought into contact with the reference wall surface 71.

  In the present embodiment, the alignment mechanism includes the alignment roller 63. However, instead of the alignment roller 63, an alignment belt portion 81 as shown in FIG. 9 may be provided.

The alignment belt portion (alignment member, rotation member, driven belt) 81 includes a driven roller 82/83 in which a rotation shaft is coupled to a housing frame (not shown) of the sheet feeding unit 20, and a driven roller 82/83. The elastic belt 84 is stretched.
That is, the alignment belt portion 81 is a driven belt (a belt having no drive mechanism) that rotates the belt in accordance with an external force.

Further, as shown in FIG. 9, the elastic belt 84 is connected to the reference guide member 61 along the rising direction (the path) of the upper end sheet at the end on the path of the upper end sheet that rises, similarly to the alignment roller 63. It is stretched to narrow the interval.
Therefore, the contact portion of the elastic belt 84 with the upper end sheet is slightly inclined so as to cover the upper end sheet.

  In this configuration, by bringing the upper sheet into contact with the elastic belt 84, the upper sheet including the upper end sheet is shifted and brought into contact with the reference guide member 61 using the force (repulsive force) from the elastic belt 84. It is like that.

In such a configuration using the alignment belt portion 81, the upper sheet of the sheet bundle raised by the elevating tray 43 comes into contact with the elastic belt 84.
Accordingly, the elastic belt 84 is elastically deformed by receiving an upward force from the upper sheet, and the elastic belt 84 rotates in the C direction together with the driven rollers 82 and 83.
At this time, the upper sheet is displaced (slids) from the original loading position toward the reference guide member 61 due to the force (reaction) received from the elastic belt 84.
As a result, similarly to the case where the alignment roller 63 is used, the upper end sheet P can be brought into contact with the reference guide member 61.

In the configuration of FIG. 9, the elastic belt 84 may be a driving belt that rotates by a driving force received from a driving source (motor). This configuration can be realized by using one of the rollers 82 and 83 as a driving roller that rotates by receiving a driving force.
In this configuration, the rotation amount of the elastic belt 84 is preferably set to an amount corresponding to the rising amount of the elevating tray 43 (a rotating amount equivalent to the rising amount). This can be realized relatively easily by using the lift motor 42 as a drive source of the elastic belt 84, for example.

Similarly, in the configuration shown in FIG. 4, the alignment roller 63 may be a driving roller that is rotated by a driving force received from a driving source (motor).
Even in this configuration, it is preferable that the rotation amount of the alignment roller 63 be an amount corresponding to the lift amount of the lift tray 43 (a rotation amount equivalent to the lift amount). This can also be realized relatively easily, for example, by using the lift motor 42 as a drive source of the alignment roller 63.

  Accordingly, the sheet feeding device according to the present invention is a sheet feeding device that raises the sheet bundle stacked on the lifting tray toward the pickup unit that picks up the upper end sheet of the sheet bundle, and is opposed to the reference wall surface with the upper end sheet interposed therebetween. The upper end sheet is formed so as to narrow the gap with the reference wall surface in the ascending direction of the upper end sheet, and comes into contact with the end portion of the rising upper end sheet so that one side of the upper end sheet contacts the reference wall surface. An alignment member for aligning the sheets is provided, the alignment member is composed of a rotating member that rotates in response to the rising of the upper end sheet, and the rotating member is an alignment belt (a driven belt or a driving belt). It can also be expressed as a paper feeding device.

  Furthermore, the sheet feeding device of the present invention is a sheet feeding device that raises the sheet bundle stacked on the lifting tray toward the pickup unit that picks up the upper end sheet of the sheet bundle, and faces the reference wall surface with the upper end sheet interposed therebetween. The upper end sheet is formed so as to narrow the gap with the reference wall surface in the ascending direction of the upper end sheet, and comes into contact with the end portion of the rising upper end sheet so that one side of the upper end sheet contacts the reference wall surface. An alignment member for aligning sheets is provided, the alignment member is a rotating member that rotates in response to the rising of the upper end sheet, and the rotating member is an alignment roller (a driven roller or a driving roller). It can also be expressed as a paper feeding device.

  In the present embodiment, the pickup roller 54 is used to take out the upper end sheet of the sheet bundle stacked on the lifting tray 43. However, the present invention is not limited to this, and another pickup device such as a pickup belt may be used instead of the pickup roller 54.

  In this embodiment, the printing apparatus is a printer that prints image data input from the outside on a printing paper (sheet) and outputs it. However, the present invention is not limited to this, and the printing apparatus may be configured as a copying machine including a scanner that reads a document image, or a facsimile apparatus including a scanner and an external communication line.

  In this embodiment, the printing apparatus collects the developer by the cleaning unit 9 and recycles it. However, the present invention is not limited to this, and the printing apparatus may be configured to discard the collected toner without recycling it.

In the present embodiment, the printing apparatus is configured such that the paper feed trays 11 and 12 can be pulled out simultaneously.
However, the present invention is not limited to this, and a configuration in which the paper feed trays 11 and 12 can be pulled out independently is also possible. In this case, it is preferable that a work space for removing sheets jammed in the second transport path 16 can be secured below the second transport path 16 by pulling out the paper feed tray 11 to the front side.

  Further, in the printing apparatus, the first transport path 15 extends in the vertical direction along the frame 17 of the paper feed unit unit 3. On the other hand, the second transport path 16 extends in a direction (horizontal direction) perpendicular to the frame 17. In this way, the paper feed trays 11 to 14 and the transport paths 15 and 16 are efficiently arranged inside the paper feed unit 3, and space saving of the paper feed unit 3 can be realized. It has become.

Further, when a sheet is jammed in the first conveyance path 15, the guide 15 a (indicated by a hatched portion in the figure) constituting the first conveyance path 15 is used as a fulcrum with the back side of the paper feeding unit 3. It turns to the near side.
As a result, the jammed sheet in the first conveyance path 15 can be removed. This removal operation is performed using a work space secured in advance between the first transport path 15 and the frame 17.

Even when the sheet is jammed in the second conveyance path 16, the guide 16 a (indicated by the hatched portion in the drawing) constituting the second conveyance path 16 is used as a fulcrum on the front side. To turn. As a result, the sheet jammed in the second conveyance path 16 can be removed.
This removal operation is performed after a paper space is secured below the second transport path 16 by pulling out the paper feed trays 11 and 12 toward the user.

  Further, the sheet feeding device of the present invention includes an elevating tray that accommodates a sheet bundle and a pickup roller that takes out a sheet that contacts the sheet bundle, and the elevating tray makes the upper end sheet of the sheet bundle contact the pickup roller. In the sheet feeding device that is moved up and down, an alignment member that adjusts the position of the upper end sheet by bringing one side of the upper end sheet taken out by the pickup roller into contact with the reference wall surface is provided. A rotating member that is disposed at a position facing the reference wall surface and contacts the end of the rising upper end sheet and moves the upper end sheet toward the reference wall surface, while rotating by a force from the rising upper end sheet. It can also be expressed as a configuration.

Further, the sheet feeding device of the present invention includes an elevating tray that accommodates a sheet bundle and a pickup roller that takes out a sheet that contacts the sheet bundle, and the elevating tray makes the upper end sheet of the sheet bundle contact the pickup roller. In the paper feeding device that moves up and down, it is placed at a position facing the reference wall surface and the reference wall surface across the sheet, contacts the end of the rising upper sheet, and the upper sheet contacts one side of the reference wall And an alignment member that adjusts the position of the upper end sheet by moving the upper end sheet, and the alignment member is expressed by a rotating member that rotates by the force from the rising upper end sheet. You can also.
The premise configuration of the sheet feeding device of the present invention can also be expressed as a sheet feeding device that raises an elevating tray that accommodates a sheet bundle so that an upper end sheet of the sheet bundle is brought into contact with a pickup roller.

The present invention also relates to a sheet feeding apparatus that is provided in a main body apparatus such as an image forming apparatus such as a printer, a facsimile machine, or a copier, and that supplies a sheet as a recording medium to the main body apparatus, and an image forming apparatus including the apparatus. It can be said that it is a thing.
Conventionally, in a sheet feeding apparatus of an image forming apparatus (printing apparatus), since the number of sheets accommodated is large, it is difficult to supply sheets from below the stacked sheets. The sheet is separated one by one from the upper part of the formed sheet by a pickup means and supplied to the image forming unit of the image forming apparatus. In this method, the sheet is fed to the image forming unit of the image forming apparatus by using a lift-up means that can move up and down while stacking the sheets so that the upper surface of the stacked sheets is always at a predetermined height. is doing. The height of the upper surface of the sheet is determined by using a detector so that the height of the pickup roller for picking up the sheet becomes a predetermined sheet supply level, and the height of the support portion for rotatably supporting the upper surface of the sheet and the pickup roller. It is controlled by detecting the like. When a sheet is fed to a main body device or the like from such a large quantity sheet feeding apparatus in which a large number of sheets are stacked and stored, the image forming quality greatly depends on the accuracy of the sheet feeding position. Therefore, a reference member is provided so that the sheet is fed to the correct position, and the sheet is fed to the correct position by feeding the sheet while aligning the sheets with the reference member. The reference member is formed by a leaf spring or the like so that it functions even when the sheet size varies due to the pressing member provided facing the reference member. It is pressed against the member side and aligned.

  Conventionally, the pressing member is positioned at the uppermost part of the portion where the sheets are stacked and stored, and it is easy to cause a trouble that the pressing member is accidentally touched and deformed when the sheet is set in the storage portion. In addition, the operation of pressing and aligning the sheet with the reference member is configured so that the sheet located on the upper part gradually presses with the lifting operation of the lifting tray for stacking the sheet, but the pressing member is fixed. It can be said that there is a problem that the sheet is easily deformed because it is a plate-like member and exerts a force to be slid and moved to the reference member side while rubbing the edge of the sheet against the pressing member.

  Further, in the present invention, the pressing member that presses the sheet against the reference member is a member that rotatably supports the pressing member, and the pressing member can be rotated by the upward movement of the sheet accompanying the lifting of the lifting tray. A sheet feeding device having high feeding accuracy and a device for reducing the deformation of the sheet by rotating from the lower side to the upper side and capable of favorably moving the sheet against the reference member. It can be said that the object is to provide an image forming apparatus provided.

  Further, the optical scanning unit 6 may scan the optical image on the uniformly charged photosensitive drum 4 to write the electrostatic latent image. The transfer unit 8 can also be said to transfer an image recorded and reproduced on the photosensitive drum 4 onto a recording medium. The cleaning unit 9 can also be said to remove the developer remaining on the photosensitive drum 4 so that a new image can be recorded on the photosensitive drum 4. In addition, there is a high possibility that a special sheet is set in the manual sheet feeding unit 18. This is because the sheets can be easily exchanged or set in the manual sheet feeding unit 18. Further, the printing apparatus selects one tray from among the sheet feeding trays 11 to 14, further separates the sheets one by one from the selected tray, and places the sheet between the photosensitive drum 4 and the transfer unit 8. It may be set to be supplied to. The transfer unit 8 preferably transfers the image recorded and reproduced on the photosensitive drum 4 to the supplied paper.

  Further, in this alignment mechanism, the rotation support of the alignment roller 63 (pressing portion) supports the rod portion 72 (roller-shaped member) rotatably with respect to the support shaft 71. Alternatively, the elastic member 73 may be supported so that it can rotate with respect to a portion (guide member) that supports the support shaft 71.

The present invention can also be expressed as the following first to seventh sheet feeding apparatuses and first image forming apparatuses.
That is, the first sheet feeding device moves up and down the storage means that stacks and stores a plurality of sheets by the lift-up means, and separates the sheets fed out from the top of the plurality of sheets one by one into the main body apparatus. In the sheet feeding apparatus for feeding, another guide that opposes the pressing portion that presses the sheet toward the reference guide surface parallel to the sheet feeding direction among the guide members that guide the sheet. The pressing portion is provided on a surface and supported by an axis substantially parallel to the sheet feeding direction with respect to the other guide surface. According to this configuration, the pressing portion that presses the sheet against the reference guide surface is rotatably supported, and thus the force that presses the sheet against the reference guide surface by the operation of lifting the sheets stacked and accommodated by the lift-up means. Since the pressing portion can be rotated in accordance with the rising of the sheet, a force for rubbing the sheet edge downward is not generated. Therefore, deformation of the sheet can be prevented and the sheet can be favorably pressed against the reference guide surface.

Further, the second sheet feeding device is configured such that, in the first sheet feeding device, the pressing portion includes a roller-shaped member that is pivotally supported. According to this configuration, the roller-shaped member is supported so as to rotate as the sheet moves up, and the outer peripheral surface of the roller-shaped member contacts the edge of the sheet, so that smooth rotation can be obtained. The edge can be prevented from being broken or bent.
In the second sheet feeding device, the third sheet feeding device further includes an elastic portion having a diameter larger than the outer periphery of the roller-shaped member. According to this configuration, by providing the elastic portion having an outer diameter larger than the outer shape of the roller-shaped member, it is possible to generate a biasing force that presses the uppermost several stacked sheets against the reference guide member. it can.

In addition, the fourth sheet feeding device is a configuration in which the elastic portion is formed of a foamable material in the third sheet feeding device. According to this configuration, since it can be partially deformed and formed with a foaming (sponge-like) material, a weak biasing force can be generated. The urging force works effectively with respect to several sheets positioned at the same position, and the load when the sheets are fed can be reduced, so that feeding jam does not occur.
Further, in the fifth sheet feeding device, the width of the elastic portion is narrower than the width of the roller-shaped member in the third or fourth sheet feeding device. According to this configuration, by reducing the width of the elastic member, it is possible to obtain a weak force that presses several sheets positioned at the uppermost portion against the reference guide member.

Further, the sixth sheet feeding device has a configuration in which a protective layer is provided on the outer peripheral surface of the elastic portion in any of the third to fifth sheet feeding devices. According to this configuration, by providing the protective layer on the outer peripheral surface of the elastic member, the edge of the sheet can be easily slipped, and the elastic portion can be prevented from being damaged by the edge of the sheet.
Further, in the seventh sheet feeding device, in any one of the second to sixth sheet feeding devices, the uppermost sheet level (height) when feeding the sheet of the sheet feeding device is a roller shape. It is the structure controlled so that it may become the height below the height of the rotation center axis | shaft of a member. According to this configuration, the level of the uppermost sheet when feeding the sheet is set to be equal to or less than the height of the rotation center axis of the roller-shaped member so that the sheet does not come off from the pressing member. Can do.
The first image forming apparatus is an image forming apparatus (printing apparatus) including any one of the first to seventh sheet feeding apparatuses. According to this configuration, the above effect can be obtained in the image forming apparatus.

  The present invention can be suitably applied to a paper feeding device of a printing apparatus that prints an image on a sheet, such as a printer, a facsimile machine, and a copying machine.

It is explanatory drawing which shows the structure of the printing apparatus concerning this Embodiment. It is a block diagram which shows the control mechanism of the printing apparatus shown in FIG. It is explanatory drawing which shows the structure of the pick-up part in the printing apparatus shown in FIG. FIG. 2 is a front view showing an alignment mechanism in a paper feeding unit of the printing apparatus shown in FIG. 1. It is explanatory drawing which shows the structure of the alignment roller in the alignment mechanism shown in FIG. FIG. 2 is a top view showing an alignment mechanism in a paper feed unit of the printing apparatus shown in FIG. 1. 7A to 7C are explanatory views showing the alignment operation in the alignment mechanism shown in FIG. FIGS. 8A to 8C are explanatory views showing other configurations of the alignment roller in the alignment mechanism shown in FIG. It is explanatory drawing which shows the structure of the alignment belt which can be equipped with the alignment mechanism shown in FIG.

Explanation of symbols

2 Printer unit 3 Paper feed unit 4 Photosensitive drum 5 Charging unit 6 Optical scanning unit 7 Development unit 8 Transfer unit 9 Cleaning unit 10 Developer supply unit 11 to 14 Paper feed tray 15 First transport path 15a Guide 16 Second transport Path 16a Guide 17 Frame 18 Manual paper feed unit 19 Manual paper feed tray 20 Paper feed unit (paper feeder)
21 Third transport path 24 Fourth transport path 26 Discharge tray 27 Fixing unit 31 Control section 32 Operation section 40 Lift tray section 41 Pickup mechanism 42 Lift motor 43 Lifting tray 44 Pulley 51 Transport roller pair 52 Separating roller 53 Feed roller 54 Pickup Roller (pickup part)
55 Sheet conveyance sensor 56 Sheet level detector 57 Upper limit detector 61 Reference guide member (reference wall surface)
62 Opposing guide member 63 Alignment roller (alignment member, rotating member, driven roller)
64 Rear end guide member 65 Front end guide member 71 Support shaft 72 Rod portion 72a Projection portion 73 Elastic member 73a Core member 74 Protective layer 81 Alignment belt portion (alignment member, rotating member, driven belt)
82/83 Driven Roller 84 Elastic Belt P Top Sheet

Claims (9)

A sheet feeding device that raises a sheet bundle stacked on a lifting tray toward a pickup unit that takes out the upper end sheet of the sheet bundle,
It is formed at the position facing the reference wall surface across the upper end sheet so as to narrow the distance from the reference wall surface along the ascending direction of the upper end sheet. An alignment member that aligns the upper end sheet so as to contact the reference wall surface is provided.
The sheet feeding device, wherein the aligning member is a rotating member that rotates by receiving the force of the rising upper end sheet.   The sheet feeding device according to claim 1, wherein the rotating member is a driven roller.   The sheet feeding device according to claim 2, wherein an elastic member is disposed on a surface of the driven roller.   The sheet feeding device according to claim 3, wherein the elastic member is formed of a foamable material.   The sheet feeding device according to claim 3, wherein the elastic member is formed on a part of the surface of the driven roller.   The sheet feeding device according to claim 3, wherein a protective layer is formed on a surface of the elastic member.   The sheet feeding device according to claim 2, wherein the center of the driven roller is disposed at a position higher than the upper end sheet taken out by the pickup unit.   The sheet feeding device according to claim 1, wherein the rotating member is a driven belt.   A printing apparatus comprising the paper feeding device according to claim 1.

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