WO2015015854A1

WO2015015854A1 - Paper feeding apparatus and image forming apparatus

Info

Publication number: WO2015015854A1
Application number: PCT/JP2014/062243
Authority: WO
Inventors: 林　陽
Original assignee: 船井電機株式会社
Priority date: 2013-07-29
Filing date: 2014-05-07
Publication date: 2015-02-05
Also published as: CN105408232A; US20160167903A1; EP3028967A1; JP2015024909A

Abstract

A paper feeding apparatus (100) is provided with: a pickup roller (21), which includes a first part (21a) that picks up paper (150) in a first state wherein the paper is to be picked up, and a second part (21b) that transfers, in a second state wherein the paper is to be transferred, the paper picked up in the first state; and a friction pad (22) that suppresses transfer of paper subsequent to the picked up paper. The pickup roller is configured to be in surface contact such that a contact area between the first part and the friction pad, and a contact area between the second part and the friction pad, are substantially equal to each other.

Description

Paper feeding device and image forming apparatus

The present invention relates to a sheet feeding device and an image forming apparatus, and more particularly to a sheet feeding device and an image forming apparatus including a pickup roller.

Conventionally, a paper feeder provided with a pickup roller is known (for example, see Patent Document 1).

In the above-mentioned Patent Document 1, a paper feeding unit that picks up paper by contacting the surface of the stacked paper in the first state where the paper is picked up, and the paper is picked up in the first state in the second state where the paper is conveyed. A paper feeding device is disclosed that includes a rotatable pickup roller that includes a hub that contacts a surface of the paper. The paper feeding device is disposed so as to face the pickup roller, and a separation pad (friction pad) for suppressing the next paper from being conveyed by contacting the next paper picked up in the first state. It has. Further, the pickup roller is configured such that in the first state, the sheet feeding portion is urged (pressed) against the page pad, and in the second state, the hub is urged (pressed) against the page pad. Further, the hub of the pickup roller has an area that is smaller than the area of the sheet feeding portion at a portion facing the separating pad.

Japanese Patent No. 4385929

However, in the paper feeder disclosed in Patent Document 1, the portion of the pickup roller that faces the separation pad of the hub has an area that is smaller than the area of the sheet feeding portion. Therefore, in the second state, the contact between the separation pad and the hub. In a state where the area is small, the hub is urged (pressed) against the burning pad. For this reason, in the second state, the contact area between the wicking pad and the hub is reduced, so that the pressure applied to the wicking pad is increased, and as a result, the wicking pad is likely to be worn or damaged.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a sheet feeding device capable of suppressing the friction pads from being easily worn and damaged. And an image forming apparatus.

A sheet feeding device according to a first aspect of the present invention is configured to contact a surface of stacked sheets in a first state where sheets are picked up and pick up the sheets, and in a second state where sheets are conveyed. A rotatable pickup roller including a second portion that contacts the surface of the paper picked up in the first state and conveys the paper, and is disposed so as to face the pickup roller, and the paper picked up in the first state The pickup roller includes a friction pad that suppresses conveyance of the next sheet by contacting the next sheet, and the pickup roller has a contact area between the first portion and the friction pad in the first state and a second in the second state. The surface contact is made so that the contact area of the part and the friction pad is substantially equal.

In the sheet feeding device according to the first aspect of the present invention, as described above, the contact area between the first portion of the pickup roller and the friction pad in the first state, and the second portion of the pickup roller and the friction pad in the second state. Even if the friction pad is biased toward the pickup roller by configuring the pickup roller so as to make surface contact so that the contact area is substantially equal, in the second state, the contact between the friction pad and the second portion Unlike the case where the second portion is biased (pressed) against the friction pad in a state where the area is small, even in the second state, the contact area is approximately equal to the contact area of the friction pad and the first portion in the first state, The second part is biased against the friction pad. Thereby, since it is possible to suppress an increase in pressure applied to the friction pad in the second state, it is possible to suppress the friction pad from being easily worn and damaged.

In the sheet feeding device according to the first aspect, preferably, the first portion of the pickup roller is configured to have a first curvature in a cross section orthogonal to the rotation axis of the pickup roller, and the second portion of the pickup roller. Is configured to have a second curvature in a cross section perpendicular to the rotation axis of the pickup roller, and the pickup roller includes a contact area between the first portion and the friction pad in the first state, and a second portion in the second state. In addition, the first curvature and the second curvature are set so that the surface contact is made so that the contact area of the friction pad is substantially equal. If comprised in this way, by adjusting the 1st curvature of the 1st part and the 2nd curvature of the 2nd part, a friction pad and the 1st part can be easily carried out in the 1st state and the 2nd state. Or the 2nd part can maintain a substantially the same surface contact state.

In the sheet feeding device according to the first aspect, preferably, a single biasing member including a first biasing portion and a second biasing portion having a biasing force weaker than the biasing force of the first biasing portion. The biasing member biases the friction pad toward the pickup roller by the first biasing portion in the first state, and biases the friction pad toward the pickup roller by the second biasing portion in the second state. It is configured to be energized. According to this configuration, the friction pad can be urged by the second urging portion having an urging force weaker than the urging force of the first urging portion in the second state. The pressure applied to the friction pad can be made smaller than in the first state. As a result, the friction pad can be easily prevented from being worn. In addition, since the single (one) urging member can be combined with the function of the first urging unit and the second urging unit having an urging force weaker than the urging force of the first urging unit, Unlike the case where the first urging unit and the second urging unit are provided separately, an increase in the number of parts can be suppressed and the structure of the paper feeding device can be simplified.

In the configuration in which the first portion has the first curvature, preferably, the pickup roller is disposed at a position where the center of curvature of the first portion and the center of curvature of the second portion are different from each other when viewed from the axial direction. It is configured. If comprised in this way, the 1st curvature of the 1st part and the 2nd curvature of the 2nd part can be adjusted individually. Thereby, the friction pad and the first part or the second part can maintain the substantially same surface contact state in the first state and the second state more easily.

In the configuration in which the curvature center of the first portion and the curvature center of the second portion are arranged at different positions, preferably, the pickup roller has a protrusion amount toward the friction pad in the first state rather than the second state. It is configured to be large. According to this configuration, the position of the first portion in the first state moves in a direction closer to the friction pad side than the position in the second state, and the position of the first portion in the second state is the position in the first state. Rather than the friction pad side. Thus, the sheet can be easily picked up in the first state and conveyed while suppressing the pressure applied to the friction pad in the second state from increasing.

In the configuration in which the amount of protrusion toward the friction pad is larger in the first state than in the second state, the pickup roller preferably has the center of curvature of the second portion when viewed from the axial direction. The center of curvature of the first part is arranged closer to the first part side than the center of the pickup roller, and the pickup roller has the center of curvature of the second part picked up. It is comprised so that it may correspond with the rotating shaft line of a roller. According to this configuration, the position of the first portion in the first state moves closer to the friction pad side than the position in the second state, and the position of the first portion in the second state is determined by a simple configuration. The position can be moved away from the friction pad side than the position in the first state.

In the configuration in which the first portion has the first curvature, preferably, in the pickup roller, the surface of the first portion having the first curvature and the surface of the second portion having the second curvature are flush with each other. It is configured as follows. If comprised in this way, when picking up a paper and conveying it, a pick-up roller can be rotated smoothly.

In this case, it is preferable to further include a first friction pad holding member and a second friction pad holding member that hold the friction pad, and the first friction pad holding member includes the first biasing portion and the second biasing member of the biasing member. It arrange | positions so that a boundary area | region with an urging | biasing part may be partitioned off, and the 2nd friction pad holding member is arrange | positioned so that a 2nd urging | biasing part may be pinched | interposed between the 1st friction pad holding members. If comprised in this way, even when providing the common urging member containing the 1st urging | biasing part and the 2nd urging | biasing part, it is suppressed that the urging | biasing force by the 1st urging | biasing part is added in a 2nd state. In this state, the second friction pad holding member (friction pad) can be biased by the second biasing portion.

In the configuration including the first friction pad holding member and the second friction pad holding member, preferably, the first friction pad holding member includes a plate-shaped partition portion, and the partition portion includes the first biasing portion and the first biasing portion. It is comprised so that it may be inserted | pinched between 2 urging | biasing parts. If comprised in this way, even when it provides the common urging member containing the 1st urging | biasing part and the 2nd urging | biasing part, the 1st urging | biasing is carried out in the 2nd state in the stable state by the partition part. The second friction pad holding member (friction pad) can be biased by the second biasing portion in a state where the biasing force applied by the portion is suppressed.

In the configuration including the partition part, the partition part preferably includes an engagement part that engages with the biasing member. If comprised in this way, it can suppress that a partition part and a biasing member shift | deviate.

In the configuration including the first friction pad holding member and the second friction pad holding member, preferably, the first friction pad holding member is configured to be restricted from moving toward the pickup roller in the second state. In the second state, the movement of the first friction pad holding member is restricted, and the second friction pad holding member is urged toward the pickup roller by urging by the second urging portion. ing. If comprised in this way, it can control in the 2nd state that the movement to the pickup roller side of a 1st friction pad holding member is controlled, and it can suppress that the urging | biasing force by a 1st urging | biasing part is added, so it is easier. Further, the second friction pad holding member (friction pad) can be biased by the second biasing portion.

In the case where the first friction pad holding member is configured so that the movement toward the pickup roller in the second state is restricted, preferably, the biasing member is a first spring portion. There is a coil spring member in which the second urging portion is the second spring portion, the first spring portion has a first pitch, and the second spring portion has a second pitch larger than the first pitch. ing. With this configuration, the urging force can be easily changed by a single spring member. Therefore, the movement of the first friction pad holding member toward the pickup roller in the second state is restricted by a simple configuration. And it can suppress that the urging | biasing force by a 1st urging | biasing part is added.

In the configuration including the first spring portion and the second spring portion, preferably, in the second state, when the first spring portion is in a natural length state, the first friction pad holding member moves toward the pickup roller. In a restricted state, the second friction pad holding member is configured to be urged toward the pickup roller by urging by the second spring portion. If comprised in this way, in a 2nd state, it can prevent a 1st spring part generating urging | biasing force with respect to a 1st friction pad holding member. Accordingly, it is possible to easily restrict the movement of the first friction pad holding member toward the pickup roller and suppress the application of the urging force by the first urging unit.

In the case where the first friction pad holding member is configured so that the movement toward the pickup roller in the second state is restricted, preferably, the second friction pad holding member is in relation to the first friction pad holding member. And is relatively movable. With this configuration, the second friction pad holding member can be easily moved independently of the first friction pad holding member in the second state. Accordingly, in the second state, the movement of the first friction pad holding member toward the pickup roller can be restricted, and the application of the urging force by the first urging unit can be further suppressed.

In the configuration further including the first friction pad holding member and the second friction pad holding member, preferably, the first portion of the pickup roller is configured to have a first curvature, and the second portion of the pickup roller is The first friction pad holding member and the second friction pad holding member are both configured to linearly move in the direction in which the biasing member expands and contracts, and the pickup roller has a second curvature. Are configured such that the first curvature of the first portion and the second curvature of the second portion are substantially equal. If comprised in this way, a friction pad can be easily urged | biased by linearly moving the 1st friction pad holding member and the 2nd friction pad holding member to the direction which an energizing member expands / contracts.

In the configuration further including the first friction pad holding member and the second friction pad holding member, preferably, the first portion of the pickup roller is configured to have a first curvature, and the second portion of the pickup roller is The second friction pad holding member is configured to rotate with respect to the first friction pad holding member, and the pickup roller includes the first portion of the first portion. The curvature is different from the second curvature of the second portion. According to this configuration, the second friction with respect to the first friction pad holding member can be achieved more than when the second friction pad holding member is linearly moved in the direction in which the biasing member expands and contracts with respect to the first friction pad holding member. Since the space for moving the pad holding member can be reduced and the friction pad can be urged, the space for arranging the second friction pad holding member can be reduced (compact).

In the configuration in which the first portion has the first curvature, preferably, the pickup roller has a shape in which a curve having the first curvature and a curve having the second curvature are connected when viewed from the axial direction. ing. With this configuration, the contact area between the friction pad and the first portion in the first state and the contact area between the friction pad and the second portion in the second state can be easily made substantially equal.

In the sheet feeding device according to the first aspect, the pickup roller is preferably configured such that the first portion is detachable. With this configuration, even when the first part needs to be replaced, only the first part can be replaced without replacing the entire pickup roller.

An image forming apparatus according to a second aspect of the present invention includes a printing unit that prints on a sheet, a first portion that contacts the surface of the stacked sheets in the first state where the sheets are picked up, and picks up the sheets, A rotatable pickup roller including a second portion that contacts the surface of the paper picked up in the first state and conveys the paper in the second state in which the paper is conveyed, and is disposed to face the pickup roller; A friction pad that suppresses conveyance of the next sheet by contacting the next sheet of the sheet picked up in the first state, and the pickup roller is in contact with the first portion and the friction pad in the first state. The surface contact is made so that the area and the contact area of the second portion and the friction pad in the second state are substantially equal. It has been.

In the image forming apparatus according to the second aspect of the present invention, as described above, the contact area between the first portion of the pickup roller and the friction pad in the first state, and the second portion of the pickup roller and the friction pad in the second state. By configuring the pickup roller so as to make surface contact so that the contact area is substantially equal, in the second state, the second part is biased by the friction pad in a state where the contact area between the friction pad and the second part is small. Unlike the case of being pressed (pressed), even in the second state, the second portion is biased to the friction pad with a contact area substantially equal to the contact area of the friction pad and the first portion in the first state. Thereby, since it is possible to suppress an increase in pressure applied to the friction pad in the second state, it is possible to suppress the friction pad from being easily worn and damaged.

According to the present invention, it is possible to suppress the friction pad from being easily worn and damaged as described above.

1 is a schematic diagram illustrating an overall configuration of a laser printer apparatus according to a first embodiment of the present invention. It is the perspective view which showed the paper separation part of the laser printer apparatus by 1st Embodiment of this invention. It is the figure which expanded and showed the paper separation part of the laser printer apparatus by 1st Embodiment of this invention. It is the figure which looked at the paper separation part of the laser printer apparatus by 1st Embodiment of this invention from the side by which a spring member is arrange | positioned. It is the figure which looked at the pick-up roller of the laser printer apparatus by 1st Embodiment of this invention from the axial direction. It is the figure which showed the 1st friction pad holding member and the 2nd friction pad holding member in the 1st state of the laser printer apparatus by 1st Embodiment of this invention. It is the figure which showed the spring member in the 1st state of the laser printer apparatus by 1st Embodiment of this invention. It is the figure which showed the 1st friction pad holding member and the 2nd friction pad holding member in the 2nd state of the laser printer apparatus by 1st Embodiment of this invention. It is the figure which showed the spring member in the 2nd state of the laser printer apparatus by 1st Embodiment of this invention. It is the figure which expanded and showed the paper separation part of the laser printer apparatus by 2nd Embodiment of this invention. It is the figure which looked at the pick-up roller of the laser printer apparatus by 2nd Embodiment of this invention from the axial direction. It is the figure which showed the 1st friction pad holding member and the 2nd friction pad holding member in the 1st state of the laser printer apparatus by 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
The configuration of the laser printer apparatus 100 according to the first embodiment of the present invention will be described with reference to FIGS. The laser printer apparatus 100 is an example of the “paper feeder” and “image forming apparatus” of the present invention.

As shown in FIG. 1, the laser printer apparatus 100 includes a paper feed tray 1 in which paper 150 is loaded, a paper separation unit 2 for separating and transporting the paper 150 stacked from the paper feed tray 1, and a paper Conveying

roller members

3 and 4 for conveying 150 to the printing position, and discharge roller members 5a to 5c for discharging the printed paper 150 to the discharge tray 6 are provided. A pair of

transport roller members

3 and 4 are provided. Further, a pair of paper discharge roller members 5a to 5c is provided. The laser printer apparatus 100 also includes a developing device 7 that performs printing on the conveyed paper 151 and a laser light emitting unit 8 that irradiates the photosensitive drum 70 of the developing device 7 with laser light. Further, the laser printer device 100 includes a heating roller member 9 and a pressure roller member 10 for fixing the toner adhering to the conveyed paper 151. Further, the paper feed tray 1 is provided with a push-up plate 11 for arranging the paper 150 at a predetermined height with respect to the paper separation unit 2. Further, as shown in FIG. 2, the sheet separating unit 2 is configured to separate and pick up the stacked sheets 150 from the sheet feeding tray 1 in a first state (see FIG. 6) described later. Further, the sheet separating unit 2 is configured to convey the sheet 151 picked up from the sheet feeding tray 1 in the first state in a second state (see FIG. 8) described later.

Here, in the first embodiment, as shown in FIGS. 3 and 4, the sheet separating unit 2 includes a pickup roller 21, a friction pad 22, a first friction pad holding member 23, and a second friction pad holding member. 24 and a spring member 25 are provided. The paper separating unit 2 is installed in the installation unit 26 (see FIG. 1).

The pickup roller 21 is configured to pick up (draw out) the stacked paper 150 from the paper feed tray 1 and transport it toward the imaging device 7 (conveying roller 4). Further, as shown in FIG. 3, the pickup roller 21 is in contact with the surface of the stacked sheets 150 in the first state where the sheets 150 are picked up (see FIG. 6) and picks up the sheets 150 and the first portion 21a. In the second state (see FIG. 8) in which the picked-up paper 151 is transported, a second portion 21b that contacts the surface of the paper 151 picked up in the first state and transports the paper is included. The pickup roller 21 includes a shaft portion 21c and is installed on the housing 100a (see FIG. 1) so as to be rotatable. Further, as shown in FIG. 5, the shaft portion 21 c is disposed in the second portion 21 b in an eccentric state from the center C of the pickup roller 21 when viewed as the entire pickup roller 21. Further, the first portion 21a and the second portion 21b are made of rubber having a function of preventing slip (for example, EPDM (ethylene propylene rubber)). The second portion 21 b is configured to form a main body portion of the pickup roller 21. The first portion 21a is configured to be detachably (replaceable) fixed to the second portion 21b. The pickup roller 21 is configured to operate when printing is performed by the developing device 7 and pick up the paper 150 from the paper feed tray 1.

As shown in FIG. 5, the first portion 21 a of the pickup roller 21 is configured to have a first curvature 1 / R in a cross section orthogonal to the rotation axis (shaft portion 21 c) of the pickup roller 21. Further, the second portion 21 b of the pickup roller 21 is configured to have a second curvature 1 / R in a cross section orthogonal to the rotation axis of the pickup roller 21. That is, the pickup roller 21 is configured such that the first curvature 1 / R of the first portion 21a and the second curvature 1 / R of the second portion 21b are substantially equal. The pickup roller 21 is formed in an asymmetric shape when viewed from the direction of the rotation axis (shaft portion 21c). The pickup roller 21 has a substantially circular shape (a shape close to a circle) as a whole when viewed from the axial direction. Further, the first portion 21a and the second portion 21b are configured such that the curvature center C1 of the first portion 21a and the curvature center C2 of the second portion 21b are at different positions. Further, the rotation center of the shaft portion 21c is arranged so as to coincide with the center C2 of the second portion 21b. The pickup roller 21 is configured such that the surface of the first portion 21a having the first curvature 1 / R and the surface of the second portion 21b having the second curvature 1 / R are flush with each other. . The pickup roller 21 is arranged such that the center of curvature C2 of the second portion 21b is located closer to the second portion 21b side than the center C (geometric center C) of the pickup roller 21 when viewed from the axial direction. The center of curvature C <b> 1 of the first portion 21 a is configured to be disposed closer to the first portion 21 a than the center C of the pickup roller 21. The pickup roller 21 is configured such that the center of curvature C2 of the second portion 21b is eccentric from the center C of the pickup roller 21 and coincides with the rotational axis of the pickup roller 21. Further, the pickup roller 21 is configured so that the amount of protrusion toward the friction pad 22 is larger in the first state than in the second state. That is, as shown in FIG. 8, in the second state, the distance from the rotation axis (curvature center C2) of the pickup roller 21 to the friction pad 22 is D2. As shown in FIG. 7, in the first state, the distance from the rotation axis of the pickup roller 21 to the friction pad 22 is D1, which is larger than D2.

As shown in FIG. 8, the friction pad 22 is disposed so as to face the pickup roller 21, and the next sheet 152 is conveyed by contacting the next sheet 152 of the sheet 151 picked up in the first state. It is comprised so that this may be suppressed. The friction pad 22 is made of rubber having a function of preventing slip (for example, EPDM (ethylene propylene rubber)). As shown in FIGS. 6 to 9, the pickup roller 21 has a contact area between the first portion 21a and the friction pad 22 in the first state and a contact area between the second portion 21b and the friction pad 22 in the second state. Are substantially equal to each other. Specifically, the pickup roller 21 is configured so that the contact area between the first portion 21a and the friction pad 22 in the first state is substantially equal to the contact area between the second portion 21b and the friction pad 22 in the second state. A first curvature 1 / R and a second curvature 1 / R (see FIG. 5) are set. The friction pad 22 is formed in a substantially arc shape corresponding to the shape of each of the first portion 21a and the second portion 21b of the pickup roller 21 when viewed from the direction of the rotation axis (shaft portion 21c). Further, the friction pad 22 and the first portion 21a or the second portion 21b of the pickup roller 21 are configured to be in surface contact. Further, as shown in FIG. 4, the friction pad 22 has substantially the same width W as the first portion 21 a of the pickup roller 21 in the direction (X direction) in which the shaft portion 21 c extends.

Further, as shown in FIG. 8, the pickup roller 21 is in the first state in the first state in a state where the friction pad 22 and the first portion 21a or the second portion 21b of the pickup roller 21 are conveyed through the paper 151. The contact area between the portion 21a and the friction pad 22 and the contact area between the second portion 21b and the friction pad 22 in the second state are substantially equal. In other words, in a state where the paper 151 on which the friction pad 22 and the first portion 21a or the second portion 21b of the pickup roller 21 are transported is sandwiched, the pickup roller 21 has the first portion 21a and the friction pad 22 in the first state. And the contact area of the second portion 21b and the friction pad 22 in the second state are substantially equal.

In the first embodiment, as shown in FIG. 3, the first friction pad holding member 23 and the second friction pad holding member 24 are configured to hold the friction pad 22. Specifically, the first friction pad holding member 23 is configured to hold the second friction pad holding member 24 to which the friction pad 22 is fixed. Further, the friction pad 22 is configured to be detachably fixed to the second friction pad holding member 24.

Further, as shown in FIG. 3, the first friction pad holding member 23 and the second friction pad holding member 24 both linearly move (translate) in the direction in which the spring member 25 expands and contracts (P direction). It is configured as follows. The second friction pad holding member 24 is configured to be movable relative to the first friction pad holding member 23. As shown in FIGS. 3 and 4, the first friction pad holding member 23 is arranged so as to partition a boundary region 25 c between the first spring portion 25 a and the second spring portion 25 b of the spring member 25. Specifically, the partition portion 23 a provided in the first friction pad holding member 23 extending in the direction (X direction) substantially orthogonal to the direction in which the spring member 25 expands and contracts (P direction) is the first spring of the spring member 25. It arrange | positions in the boundary area | region 25c of the part 25a and the 2nd spring part 25b. Moreover, the partition part 23a is formed in plate shape. Further, the partition portion 23 a has a thickness smaller than the pitch in the vicinity of the boundary region 25 c of the spring member 25. Moreover, the partition part 23a is comprised so that it may be pinched | interposed between the 1st spring part 25a and the 2nd spring part 25b. The first friction pad holding member 23 (partition portion 23a) includes a fixing portion 23b that suppresses the first spring portion 25a (spring member 25) from coming off. The fixed portion 23b is configured to protrude in the direction in which the first spring portion 25a expands and contracts (P2 direction). The fixing portion 23b is fitted into the inner diameter portion of the first spring portion 25a (spring member 25), thereby preventing the first spring portion 25a (spring member 25) from being detached from the first friction pad holding member 23. It is configured. That is, the fixing portion 23b has a function as an engaging portion that engages with the first spring portion 25a (spring member 25).

The second friction pad holding member 24 is disposed so as to sandwich the second spring portion 25b between the first friction pad holding member 23 and the first friction pad holding member 23, as shown in FIGS. The second friction pad holding member 24 includes a fixing portion 24a that suppresses the second spring portion 25b (spring member 25) from being detached. The fixing portion 24a is configured to protrude in the direction in which the first spring portion 25a expands and contracts (P2 direction). The fixing portion 24 a is fitted into the inner diameter portion of the second spring portion 25 b (spring member 25) so that the second spring portion 25 b (spring member 25) is prevented from coming off from the second friction pad holding member 24. It is configured.

Further, in the first embodiment, as shown in FIGS. 8 and 9, the first friction pad holding member 23 is restricted from moving toward the pickup roller 21 (P1 direction) in the second state. It is configured. Specifically, the first friction pad holding member 23 moves in the direction in which the spring member 25 expands and contracts in the first state (the state where the paper 151 is disposed between the first portion 21a and the friction pad 22). It is configured to be possible. In addition, the first friction pad holding member 23 is in the second state (the state in which the sheet 151 picked up in the first state is conveyed and the sheet 152 subsequent to the picked up sheet 151 is not conveyed) (see FIG. 2), the movement in the direction in which the spring member 25 expands and contracts (the pickup roller 21 side (P1 direction side)) is restricted. Further, in the second state, the movement of the first friction pad holding member 23 is restricted, and the second friction pad holding member 24 is urged by the second spring portion 25b (spring member 25) so as to be on the pickup roller 21 side. Is configured to be biased. The first friction pad holding member 23 and the second friction pad holding member 24 are made of resin.

In the first embodiment, the spring member 25 includes, for example, a coil spring. As shown in FIG. 3, the spring member 25 includes a single spring member including a first spring portion 25a and a second spring portion 25b having a biasing force that is weaker than the biasing force of the first spring portion 25a. Yes. The spring member 25 includes a second spring portion 25b on the pickup roller 21 side (P1 direction side), and includes a first spring portion 25a on the opposite side (P2 direction side) to the pickup roller 21 side. The natural length first spring portion 25a has a first pitch smaller than the second pitch of the natural length second spring portion 25b. The spring member 25 biases the friction pad 22 toward the pickup roller 21 by the first spring portion 25a in the first state, and the friction pad 22 toward the pickup roller 21 by the second spring portion 25b in the second state. Is configured to energize. The spring member 25 is configured such that, in the second state, the first spring portion 25a has a natural length. That is, in the second state, the friction pad 22 is biased toward the pickup roller 21 by the biasing force of the second spring portion 25b. In other words, in the second state, the second friction pad holding member is in a state where movement of the first friction pad holding member 23 toward the pickup roller 21 is restricted by the first spring portion 25a being in a natural length state. 24 is configured to be urged toward the pickup roller 21 by urging by the second spring portion 25b. The spring member 25 is an example of the “biasing member” in the present invention. The first spring portion 25a is an example of the “first biasing portion” in the present invention. The second spring portion 25b is an example of the “second biasing portion” in the present invention.

As shown in FIG. 1, the developing device 7 includes a photosensitive drum 70 for printing with the toner attached to the conveyed paper 151, a developing roller 71 for supplying toner to the photosensitive drum 70, and a developing unit. A supply roller 72 and a regulation roller 73 for supplying toner to the roller 71 are included. Further, the developing roller 71, the supply roller 72, and the regulation roller 73 are all disposed in the toner carrying region 74. The developing device 7 is an example of the “printing unit” in the present invention.

The developing device 7 also removes a toner supply passage 75 that supplies toner to the toner carrying region 74, a toner cartridge 76 that stores new toner, old toner that has adhered to the developing roller 71, and old toner around the developing roller 71. And an old toner recovery unit 77 for recovery. The developing device 7 is disposed at a position facing the photosensitive drum 70, and remains on the photosensitive drum 70, and a transfer roller 78 for transferring the toner attached to the photosensitive drum 70 onto the conveyed paper 151. And a cleaning unit 79 for collecting the toner.

The photosensitive drum 70 is configured such that the surface is negatively charged. Further, in the photosensitive drum 70 at the time of printing, first, laser light from the laser light emitting unit 8 is irradiated on a predetermined surface of the photosensitive drum 70 along the rotation direction of the photosensitive drum 70, and the irradiated position. The negative charge on the surface is removed. As a result, an electrostatic latent image is created on the surface of the photosensitive drum 70 where the negative charges have been removed. Thereafter, the toner supplied by the developing roller 71 adheres to the electrostatic latent image on the photosensitive drum 70. Then, the negatively charged toner moves from the photosensitive drum 70 toward the transfer roller 78 by the positively charged transfer roller 78, whereby the paper 151 conveyed between the transfer roller 78 and the photosensitive drum 70. The toner is adsorbed (transferred) to the surface. As a result, printing is performed on the conveyed paper 151 based on the electrostatic latent image on the photosensitive drum 70.

Thereafter, on the photosensitive drum 70, after the negative charge on the surface is removed, the toner remaining on the surface is collected by the cleaning unit 79. Finally, a negative charge is charged again on the surface of the photosensitive drum 70 by an electrode (not shown), and the printing operation is performed again.

Next, the operation of the sheet separating unit 2 when separating and transporting the stacked sheets 150 from the sheet feeding tray 1 will be described with reference to FIGS. 6 and 8, for convenience of explanation, the installation unit 26 is omitted, and the paper separating unit 2 viewed from the direction of the rotation axis (the shaft portion 21c) is illustrated. 7 and 9, for convenience of explanation, the installation unit 26 and the first friction pad holding member 23 are omitted, and the paper separating unit 2 viewed from the direction of the rotation axis (shaft portion 21c) is illustrated.

With reference to FIG. 6 and FIG. 7, a state in which the paper 150 stacked on the paper feed tray 1 is picked up (drawn) in the first state will be described. First, by rotating the pickup roller 21 in the A direction, the paper 150 stacked on the paper feed tray 1 is sandwiched between the first portion 21 a and the friction pad 22. Thereafter, until the end portion 21e of the pickup roller 21 is rotated to a position corresponding to the spring member 25, the spring member 25 (the first spring portion 25a and the second spring portion 25b) is opposite to the pickup roller 21 side. It is urged to (P2 direction side). The friction pad 22 is biased toward the pickup roller 21 by the first spring portion 25a and the second spring portion 25b, so that the pickup is performed with the sheet sandwiched between the first portion 21a and the friction pad 22. The roller 21 is rotated in the A direction. Subsequently, the pickup roller 21 is further rotated in the A direction from the state where the end 21e of the pickup roller 21 is disposed at the position corresponding to the spring member 25, and the state is shifted to the second state.

Referring to FIGS. 8 and 9, a state in which the paper 151 picked up (drawn) in the first state is conveyed toward the imaging device 7 in the second state will be described. The pickup roller 21 is rotated in the A direction from the state where the end portion 21e of the pickup roller 21 is disposed at a position corresponding to the spring member 25, whereby the paper 151 between the first portion 21a and the friction pad 22 is moved. Be transported. At this time, the pickup roller 21 is disposed at a position moved to the upper side (P1 direction side) from the first state by the eccentric shaft portion 21c. Further, in the second state, the friction pad 22 is restricted from moving on the pickup roller 21 side (P1 direction side) of the first friction pad holding member 23, so that the pickup roller 21 is moved by the second spring portion 25 b of the spring member 25. It is energized towards. Thereby, in the second state, the friction pad 22 is urged toward the pickup roller 21 with an urging force that is weaker than the urging force in the first state (the force for pinching the paper 150). The sheet 151 can be conveyed toward the imaging device 7 (conveyance roller member 4) while suppressing the conveyance of the sheet 152 (the sheet 151 and the sheet 152 are simultaneously conveyed (multiple feed)). is there.

In the first embodiment, as described above, the contact area between the first portion 21a of the pickup roller 21 and the friction pad 22 in the first state, and the contact between the second portion 21b of the pickup roller 21 and the friction pad 22 in the second state. The pickup roller 21 is configured to make surface contact so that the area is substantially equal. Thus, even when the friction pad 22 is biased toward the pickup roller 21, the second portion 21b is attached to the friction pad 22 in a state where the contact area between the friction pad 22 and the second portion 21b is small in the second state. Unlike the case of being pressed (pressed), even in the second state, the second portion 21b is biased against the friction pad 22 with a contact area substantially equal to the contact area between the friction pad 22 and the first portion 21a in the first state. Is done. Thereby, since it is possible to suppress an increase in pressure applied to the friction pad 22 in the second state, it is possible to prevent the friction pad 22 from being easily worn and damaged.

In the first embodiment, as described above, the first portion 21a of the pickup roller 21 is configured to have the first curvature in the cross section orthogonal to the rotation axis of the pickup roller 21, and the pickup roller 21 The second portion 21b of the pickup roller 21 is configured to have a second curvature in a cross section perpendicular to the rotation axis, and the contact area between the first portion 21a and the friction pad 22 in the first state and the second portion 21b in the second state. The pickup roller 21 is configured by setting the first curvature and the second curvature so that the surface contact is made so that the contact area between the two portions 21b and the friction pad 22 is substantially equal. Thereby, the friction pad 22 and the 1st part 21a or the 2nd part 21b can maintain the substantially same surface contact state easily in a 1st state and a 2nd state.

In the first embodiment, as described above, the single spring member 25 including the first spring portion 25a and the second spring portion 25b having a biasing force weaker than the biasing force of the first spring portion 25a is provided. In the first state, the friction pad 22 is biased toward the pickup roller 21 by the first spring portion 25a, and in the second state, the friction pad 22 is biased toward the pickup roller 21 by the second spring portion 25b. Thus, the spring member 25 is configured. Accordingly, in the second state, the friction pad 22 can be biased by the second spring portion 25b having a biasing force that is weaker than the biasing force of the first spring portion 25a. Also, the pressure applied to the friction pad 22 can be reduced. Thereby, it is possible to easily suppress the friction pad 22 from being easily worn. In addition, since the single (one) spring member 25 can be combined with the function of the first spring portion 25a and the second spring portion 25b having an urging force weaker than the urging force of the first spring portion 25a, Unlike the case where the first spring portion 25a and the second spring portion 25b are provided separately, an increase in the number of parts can be suppressed, and the structure of the laser printer device 100 can be simplified.

In the first embodiment, as described above, the pickup roller 21 is configured so that the curvature center C1 of the first portion 21a and the curvature center C2 of the second portion 21b are arranged at different positions. Thereby, 1st curvature 1 / R of the 1st part 21a and 2nd curvature 1 / R of the 2nd part 21b can be adjusted separately. As a result, the friction pad 22 and the first portion 21a or the second portion 21b can be maintained in substantially the same surface contact state in the first state and the second state more easily.

In the first embodiment, as described above, the pickup roller 21 is configured so that the amount of protrusion toward the friction pad 22 is larger in the first state than in the second state. As a result, the position of the first portion 21a in the first state moves in a direction closer to the friction pad 22 than the position in the second state, and the position of the first portion 21a in the second state is greater than the position in the first state. Can also move away from the friction pad 22 side. As a result, it is possible to easily pick up the paper 150 in the first state and transport the paper 22 while suppressing an increase in pressure applied to the friction pad 22 in the second state.

In the first embodiment, as described above, the center of curvature C2 of the second portion 21b is disposed on the second portion 21b side of the center C of the pickup roller 21, and the center of curvature C1 of the first portion 21a is The pickup roller 21 is configured so as to be disposed closer to the first portion 21a than the center C of the pickup roller 21. Further, the pickup roller 21 is configured such that the center of curvature C2 of the second portion 21b coincides with the rotation axis of the pickup roller 21. Thus, with a simple configuration, the position of the first portion 21a in the first state moves in a direction closer to the friction pad 22 than the position in the second state, and the position of the first portion 21a in the second state is the first position. It can move in a direction away from the friction pad 22 side than the position in the first state.

In the first embodiment, as described above, the surface of the first portion 21a having the first curvature 1 / R and the surface of the second portion 21b having the second curvature 1 / R are flush with each other. The pickup roller 21 is configured as described above. Accordingly, the pickup roller 21 can be smoothly rotated when the sheet 150 is picked up and conveyed.

In the first embodiment, as described above, the first friction pad holding member 23 and the second friction pad holding member 24 that hold the friction pad 22 are provided, and the first spring portion 25a and the second friction pad holding member 24 of the spring member 25 are provided. The first friction pad holding member 23 is disposed so as to partition the boundary region with the spring portion 25b, and the second friction pad holding member 24 is disposed so as to sandwich the second spring portion 25b between the first friction pad 22 holding member and the first friction pad holding member 23. Deploy. Thereby, even when the common spring member 25 including the first spring portion 25a and the second spring portion 25b is provided, in the second state, the application of the urging force by the first spring portion 25a is suppressed. The second friction pad holding member 24 (friction pad 22) can be biased by the second spring portion 25b.

Further, in the first embodiment, as described above, the plate-like partition portion 23a is configured to be sandwiched between the first spring portion 25a and the second spring portion 25b. Accordingly, the second friction pad holding member 24 is held by the second spring portion 25b in a stable state by the partition portion 23a and in a state where the urging force by the first spring portion 25a is suppressed in the second state. Can be energized.

In the first embodiment, as described above, the partition portion 23a is configured to include the fixing portion 23b that functions as an engaging portion that engages with the first spring portion 25a. Thereby, it can control that partition part 23a and the 1st spring part 25a shift.

In the first embodiment, as described above, the first friction pad holding member 23 is configured so that the movement toward the pickup roller 21 is restricted in the second state, and the first friction is in the second state. The second friction pad holding member 24 is configured to be urged toward the pickup roller 21 by the urging by the second spring portion 25b in a state where the movement of the pad holding member 23 is restricted. Thereby, in the second state, the movement of the first friction pad holding member 23 to the pickup roller 21 side can be restricted and the biasing force applied by the first spring portion 25a can be suppressed, so that more easily, The second friction pad holding member 24 (friction pad 22) can be biased by the second spring portion 25b.

Further, in the first embodiment, as described above, the second spring portion 25b is configured to have a second pitch larger than the first pitch of the first spring portion 25a. As a result, the urging force can be easily changed by the single spring member 25, so that the movement of the first friction pad holding member 23 toward the pickup roller 21 in the second state is restricted with a simple configuration. Thus, it is possible to suppress the urging force from being applied by the first spring portion 25a.

Further, in the first embodiment, as described above, the movement of the first friction pad holding member 23 toward the pickup roller 21 is restricted by the natural state of the first spring portion 25a in the second state. In this state, the second friction pad holding member 24 is configured to be biased toward the pickup roller 21 by the biasing force of the second spring portion 25b. Thereby, in the second state, it is possible to prevent the first spring portion 25a from generating an urging force against the first friction pad holding member 23. As a result, it is possible to easily restrict the movement of the first friction pad holding member 23 toward the pickup roller 21 and suppress the application of the urging force by the first spring portion 25a.

In the first embodiment, as described above, the second friction pad holding member 24 is configured to be movable relative to the first friction pad holding member 23. Thereby, in the second state, the second friction pad holding member 24 can be easily moved independently of the first friction pad holding member 23.

In the first embodiment, as described above, the first friction pad holding member 23 and the second friction pad holding member 24 are configured so as to linearly move in the direction in which the spring member 25 expands and contracts. The pickup roller 21 is configured so that the first curvature of the portion 21a and the second curvature of the second portion 21b are substantially equal. Thereby, the friction pad 22 can be easily biased by linearly moving the first friction pad holding member 23 and the second friction pad holding member 24 in the direction in which the spring member 25 expands and contracts.

In the first embodiment, as described above, the pickup roller 21 is configured to have a shape in which a curve having the first curvature 1 / R and a curve having the second curvature 1 / R are connected. Accordingly, the contact area between the friction pad 22 and the first portion 21a in the first state and the contact area between the friction pad 22 and the second portion 21b in the second state can be easily made substantially equal.

In the first embodiment, as described above, the pickup roller 21 is configured such that the first portion 21a is detachable. Thereby, even when it becomes necessary to replace the first portion 21a, only the first portion 21a can be replaced without replacing the entire pickup roller 21.

(Second Embodiment)
The configuration of the laser printer device 200 according to the second embodiment of the present invention will be described below with reference to FIGS. The laser printer device 200 is an example of the “paper feeding device” and “image forming device” in the present invention.

In the second embodiment, the first friction pad holding member 23 and the second friction pad holding member 24 are both configured to move linearly in a direction (P direction) in which the spring member 25 expands and contracts. Unlike the embodiment, a laser printer device 200 configured such that the second friction pad holding member 124 rotates with respect to the first friction pad holding member 123 will be described.

As shown in FIG. 10, the paper separation unit 102 of the laser printer device 200 according to the second embodiment includes a pickup roller 121, a friction pad 22, a first friction pad holding member 123, and a second friction pad holding member 124. And a spring member 25.

Here, in the second embodiment, the pickup roller 121 includes a first portion 121a that picks up the paper 150 by contacting the surface of the stacked paper 150 in the first state where the paper 150 is picked up by the first portion 121a. In the second state in which the picked-up paper 151 is conveyed, a second portion 121b that contacts the surface of the paper 151 picked up in the first state and conveys the paper is included.

As shown in FIG. 11, the first portion 121a of the pickup roller 121 is configured to have a first curvature 1 / R1 in a cross section orthogonal to the rotation axis (shaft portion 121c) of the pickup roller 121. That is, the second portion 121b of the pickup roller 121 is configured to have a second curvature 1 / R2 in a cross section orthogonal to the rotation axis of the pickup roller 121. That is, the pickup roller 121 is configured such that the first curvature 1 / R1 of the first portion 121a is different from the second curvature 1 / R2 of the second portion 121b. The pickup roller 121 is configured such that the contact area between the first portion 121a and the friction pad 22 in the first state is substantially equal to the contact area between the second portion 121b and the friction pad 22 in the second state. . Specifically, the pickup roller 121 is configured such that the contact area between the first portion 121a and the friction pad 22 in the first state is substantially equal to the contact area between the second portion 121b and the friction pad 22 in the second state. A first curvature 1 / R1 and a second curvature 1 / R2 are set.

As shown in FIG. 10, the first friction pad holding member 123 includes a partition portion 123a disposed in a boundary region 25c between the first spring portion 25a and the second spring portion 25b of the spring member 25, and a first spring portion 25a. And a fixing portion 123b that suppresses the spring member 25 from coming off. The second friction pad holding member 124 includes a fixing portion 124a that suppresses the second spring portion 25b (spring member 25) from being detached.

In the second embodiment, as shown in FIG. 12, the second friction pad holding member 124 is configured to rotate with respect to the first friction pad holding member 123. Specifically, as shown in FIG. 10, the second friction pad holding member 124 is provided with a pair of convex portions 124b at both ends in the extending direction (X direction) of the shaft portion 121c. The pair of convex portions 124b are formed so as to protrude in the extending direction of the shaft portion 121c. Further, the first friction pad holding member 123 is formed with a hole 123 c at a position corresponding to the convex portion 124 b of the second friction pad holding member 124. The second friction pad holding member 124 is configured to be rotatable around the convex portion 124b by fitting the convex portion 124b into the hole 123c of the first friction pad holding member 123. In the second state, in the state where the movement of the first friction pad holding member 123 is restricted, the second friction pad holding member 124 is driven by the urging force of the second spring portion 25b (spring member 25). It is configured to be turned to the side (P1 direction side).

In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

In the second embodiment, as described above, the contact area between the first portion 121a of the pickup roller 121 and the friction pad 22 in the first state, and the contact between the second portion 121b of the pickup roller 121 and the friction pad 22 in the second state. The pickup roller 121 is configured so as to make surface contact so that the area is substantially equal. Thus, even when the friction pad 22 is biased toward the pickup roller 121, the second portion 121b is attached to the friction pad 22 in a state where the contact area between the friction pad 22 and the second portion 121b is small in the second state. Unlike the case of being pressed (pressed), even in the second state, the second portion 121b is biased against the friction pad 22 with a contact area substantially equal to the contact area of the friction pad 22 and the first portion 121a in the first state. Is done. Thereby, since it is possible to suppress an increase in pressure applied to the friction pad 22 in the second state, it is possible to prevent the friction pad 22 from being easily worn and damaged.

Further, in the second embodiment, as described above, the second friction pad holding member 124 is configured to rotate with respect to the first friction pad holding member 123, and the first curvature of the first portion 121a and the first curvature The pickup roller 121 is configured so that the second curvature of the two portions 121b is different. As a result, the second friction pad with respect to the first friction pad holding member 123 can be obtained compared to the case where the second friction pad holding member 124 is linearly moved in the direction in which the spring member 25 expands and contracts with respect to the first friction pad holding member 123. Since the friction pad 22 can be biased by reducing the space when the holding member 124 moves, the space for arranging the second friction pad holding member 124 can be reduced (compact).

The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

In addition, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

For example, in the first and second embodiments, an example in which the present invention is applied to a laser printer apparatus as an example of an image forming apparatus has been described, but the present invention is not limited thereto. The present invention may be applied to, for example, an ink jet printer apparatus other than the laser printer apparatus, and may be applied to other image forming apparatuses such as a facsimile.

In the first and second embodiments, the first spring portion 25a (first biasing portion) and the second spring portion 25b (second biasing force) having a biasing force that is weaker than the biasing force of the first spring portion 25a. However, the present invention is not limited to this example. In the present invention, two urging members provided with the first urging portion and the second urging portion separately may be provided.

In the first and second embodiments, the example in which the spring member including the coil spring is provided as the biasing member of the present invention is shown, but the present invention is not limited to this. In the present invention, for example, a biasing member other than a coil spring, such as a leaf spring, or a biasing member other than a spring may be used.

In the first and second embodiments, the example in which the shaft portion 21c is provided in an eccentric state when viewed from the direction of the rotation axis (shaft portion 21c) is shown. However, the present invention is not limited to this. Absent. In the present invention, when viewed from the direction of the rotation axis (shaft portion 21c), the shaft portion 21c may be provided on the pickup roller without being eccentric.

In the first and second embodiments, the first friction pad holding member and the second friction pad holding member are separately configured. However, the present invention is not limited to this. In the present invention, the first friction pad holding member and the second friction pad holding member may be configured integrally.

7 Development device (printing section)
21, 121

Pickup rollers

21a, 121a

First part

21b, 121b Second part 22

Friction pad

23, 123 First friction pad holding member

23a Partition part

24, 124 Second friction pad holding member 25 Spring member (biasing member)
25a 1st spring part (1st biasing part)
25b Second spring portion (second biasing portion)

25c Boundary area

100, 200 Laser printer device (paper feeding device, image forming device)

Claims

The first portion (21a, 121a) that picks up the paper by contacting the surface of the stacked paper in the first state where the paper (150) is picked up, and the first state in the second state where the paper is conveyed A rotatable pickup roller (21, 121) including a second portion (21b, 121b) that contacts the surface of the picked-up paper and conveys the paper;
A friction pad (22) disposed so as to face the pickup roller and restraining the next paper from being conveyed by contacting the next paper picked up in the first state;
The pickup roller is in surface contact so that a contact area between the first portion and the friction pad in the first state is substantially equal to a contact area between the second portion and the friction pad in the second state. A sheet feeding device (100, 200) configured as described above.
The first portion of the pickup roller is configured to have a first curvature in a cross section perpendicular to the rotation axis of the pickup roller,
The second portion of the pickup roller is configured to have a second curvature in a cross section perpendicular to the rotation axis of the pickup roller;
The pickup roller is in surface contact so that a contact area between the first portion and the friction pad in the first state is substantially equal to a contact area between the second portion and the friction pad in the second state. The sheet feeding device according to claim 1, wherein the first curvature and the second curvature are set.
A single biasing member (25) including a first biasing portion (25a) and a second biasing portion (25b) having a biasing force weaker than the biasing force of the first biasing portion;
In the first state, the urging member urges the friction pad toward the pickup roller by the first urging portion, and in the second state, the urging member acts on the pickup roller by the second urging portion. The sheet feeding device according to claim 1, wherein the sheet feeding device is configured to bias the friction pad toward the surface.
3. The sheet feeding device according to claim 2, wherein the pickup roller is configured to be disposed at a position where a center of curvature of the first portion and a center of curvature of the second portion are different from each other when viewed in the axial direction. .
The sheet feeding device according to claim 4, wherein the pickup roller is configured to have a larger protrusion amount toward the friction pad in the first state than in the second state.
The pickup roller is arranged such that the center of curvature of the second portion is disposed closer to the second portion than the center of the pickup roller when viewed from the axial direction, and the center of curvature of the first portion is the center of the pickup roller. Than the first part side,
The sheet feeding device according to claim 5, wherein the pickup roller is configured such that a center of curvature of the second portion coincides with a rotation axis of the pickup roller.
The pickup roller is configured such that a surface of the first portion having the first curvature and a surface of the second portion having the second curvature are flush with each other. Paper feeder.
A first friction pad holding member (23, 123) for holding the friction pad and a second friction pad holding member (24, 124);
The first friction pad holding member is disposed so as to partition a boundary region between the first urging portion and the second urging portion of the urging member,
4. The sheet feeding device according to claim 3, wherein the second friction pad holding member is disposed so as to sandwich the second urging portion with the first friction pad holding member. 5.
The first friction pad holding member includes a plate-like partition (23a),
The sheet feeding device according to claim 8, wherein the partition portion is configured to be sandwiched between the first urging portion and the second urging portion.
The sheet feeding device according to claim 9, wherein the partition portion includes an engaging portion that engages with the urging member.
The first friction pad holding member is configured to be restricted from moving toward the pickup roller in the second state,
In the second state, in a state where the movement of the first friction pad holding member is restricted, the second friction pad holding member is urged toward the pickup roller by the urging by the second urging portion. The sheet feeding device according to claim 8, configured as described above.
The biasing member is a coil spring member (25) in which the first biasing portion is a first spring portion (25a) and the second biasing portion is a second spring portion (25b).
The first spring portion has a first pitch,
The sheet feeding device according to claim 11, wherein the second spring portion has a second pitch larger than the first pitch.
In the second state, the second friction pad holding member is in a state where the movement of the first friction pad holding member toward the pickup roller is restricted by the natural length of the first spring portion. The sheet feeding device according to claim 12, wherein the sheet feeding device is configured to be biased toward the pickup roller by biasing by the second spring portion.
The sheet feeding device according to claim 11, wherein the second friction pad holding member is configured to be movable relative to the first friction pad holding member.
The first portion of the pickup roller is configured to have a first curvature;
The second portion of the pickup roller is configured to have a second curvature;
The first friction pad holding member and the second friction pad holding member are both configured to move linearly in a direction in which the biasing member expands and contracts,
The paper feeding device according to claim 14, wherein the pickup roller is configured such that a first curvature of the first portion and a second curvature of the second portion are substantially equal.
The first portion of the pickup roller is configured to have a first curvature;
The second portion of the pickup roller is configured to have a second curvature;
The second friction pad holding member is configured to rotate with respect to the first friction pad holding member,
The paper feeding device according to claim 14, wherein the pickup roller is configured such that a first curvature of the first portion and a second curvature of the second portion are different.
The sheet feeding device according to claim 2, wherein the pickup roller has a shape in which the curve having the first curvature and the curve having the second curvature are connected to each other when viewed from the axial direction.
The paper feeding device according to claim 1, wherein the pickup roller is configured such that the first portion is detachable.
A printing section (7) for printing on paper;
A first portion that contacts the surface of the stacked paper in the first state where the paper is picked up and contacts the surface of the paper picked up in the first state in the second state where the paper is transported A rotatable pickup roller including a second portion for conveying the sheet,
A friction pad disposed so as to face the pickup roller and restraining the next paper from being conveyed by contacting the next paper picked up in the first state;
The pickup roller is in surface contact so that a contact area between the first portion and the friction pad in the first state is substantially equal to a contact area between the second portion and the friction pad in the second state. An image forming apparatus (100, 200).
The first portion of the pickup roller is configured to have a first curvature in a cross section perpendicular to the rotation axis of the pickup roller,
The second portion of the pickup roller is configured to have a second curvature in a cross section perpendicular to the rotation axis of the pickup roller;
The pickup roller is in surface contact so that a contact area between the first portion and the friction pad in the first state is substantially equal to a contact area between the second portion and the friction pad in the second state. The image forming apparatus according to claim 19, wherein the first curvature and the second curvature are set.