JP2000255800A - Sheet material feeder and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate later sorting work by stacking recorded sheets recorded with image information with purposefully shifting the stack positions of the respective sheets. SOLUTION: In this sheet material feeder, a paper discharge part has a discharge roller 71 for discharging a recorded sheet to a recorded sheet stack tray 73, and a flapper 74 turning around its upper side toward the recorded sheet stack tray 73 near the discharge roller 71 immediately in front of the recorded sheet stack tray 73. The flapper 74 turns interlockingly with the discharge operation wherein the turning of the discharge roller 71 discharges the recorded sheet to the recorded sheet stack tray 73.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus for feeding a sheet loaded on a sheet holding unit, and an image forming apparatus such as a printer, a copying machine, a facsimile, etc. using the sheet feeding apparatus. Related to the device.

[0002]

2. Description of the Related Art Recent laser beam printers (hereinafter referred to as L
Abbreviated as BP. ), Etc., are increasingly miniaturized,
LBP, which has been used only in limited applications and environments such as office or business use, has been reduced in price.
However, in conjunction with the spread of personal computers, it has also been used in privately owned offices and homes. Along with this, the LBP body itself has been improved not only in terms of its basic performance, but also so that anyone can handle it easily and easily.

For example, in recent LBPs and the like, the user can easily replace consumables such as a process cartridge as a recording (printing) unit and deal with a slight trouble such as a paper jam simply by opening an openable cover. Some ideas have been devised to make it possible to perform such operations in a simple manner.

[0004]

Incidentally, in an image forming apparatus such as an LBP, a sheet material of a somewhat limited type (hereinafter, referred to as recommended paper) recommended by a manufacturer is generally used. Considering the usage environment in which the recommended paper is used, the selection and design of components in a recording (printing) section, a paper feeding section (sheet feeding section), and the like are performed so as to be optimal in the usage environment. Was.
For example, a paper feed roller used in the paper feed unit that feeds (feeds) a sheet material to the recording unit in the apparatus main body also has an optimal durability life in a state where recommended paper is used. Rollers have been used.

[0005] On the other hand, recently, various kinds of paper (eg, non-brand low-price paper, ink-jet printer paper, etc.) that can be purchased at stationery stores, discount stores, and the like have been frequently used. In the past, North America,
LBP used mainly in Europe and Japan
However, recently, it has been widely used in Southeast Asia, Central and South America, Eastern Europe, and the like, and the quality of paper used has been inferior to the quality of recommended paper. Further, when an individual user uses the image forming apparatus,
Various types of sheet materials may be used for printing, such as various postcards / postcards / envelopes, Japanese paper, various thicknesses of paper, and even plastic films other than paper, according to the purpose and taste of the user. .

However, since these various sheet materials often differ from the characteristics of the recommended paper, various troubles may occur when the image forming apparatus is used for a relatively long period of time.

For example, depending on the type of sheet material used as a recording medium, the frictional force of the above-described paper feed roller may be reduced to cause a paper feed failure before printing. Specifically, the coating / pigment applied to the sheet material or the additive (talc, calcium carbonate, kaolin, etc.) added to the paper adheres and accumulates on the surface of the feed roller, and In many cases, paper feed failure occurs due to factors such as a reduction in the frictional force of the paper feeder or an abrasion of the paper feed roller rubber due to reasons such as roughness of the paper surface / roughness of the fiber.

The paper feed roller in such a state needs to be cleaned with a solvent such as alcohol or replaced with a new paper feed roller. However, the fact that solvents such as alcohol are not readily available or that improvements have been made to make it easier for anyone to use, the user cannot replace the paper feed roller as easily as the process cartridge described above. For such reasons, it is common to request a manufacturer for repair.

To cope with such a problem, Japanese Patent Application No. Hei 10-256240 has proposed an image forming apparatus having a paper feed unit that allows a user to easily replace a paper feed roller. In a paper feeding unit of the image forming apparatus,
As shown in FIG. 7, a paper feed roller supporting plate 1 in which a paper feed roller 101 having a substantially half-moon shape
02 is detachably supported. Here, the paper feed roller 101 is attached to the core member 103 having a substantially half-moon-shaped cross section by a rubber member 1.
The arc-shaped main surface of the rubber member 104 from the portion A to the portion B in FIG. 7A is attached to a sheet material (hereinafter, referred to as a sheet) stacked on a sheet feeding tray (not shown). )) For feeding paper. Further, protrusions 101a and 101b and recesses 102a and 102b that constitute a locking mechanism for attaching and detaching the paper feed roller 101 are formed on the core metal part 103 and the paper feed roller support plate 102 of the paper feed roller 101. ing.

In FIG. 7, reference numeral 105 denotes a paper feed roller which rotates integrally with the paper feed roller shaft 100, and reference numeral 106 denotes a paper feed roller which feeds an upper layer of paper stacked on a paper feed tray.
5 and a middle plate to be supplied to the paper feed roller 101, 107 is a spring for urging the middle plate 106 toward the paper feed roller 105 and the paper feed roller 101, and 108 is a further upstream side of the paper picked up by the paper feed roller 101. Transport rollers for transporting the paper to the printer. In this paper feed unit, when the paper feed roller shaft 100 is driven to rotate in the direction of arrow D in FIG. 7A by a drive source (not shown), a paper feed roller support plate 102 integrated with the paper feed roller shaft 100 is provided. And the paper feed roller support plate 102
The paper feed roller 101 supported by the
Only one sheet of paper (not shown) located on the middle plate 106 of the paper feed roller 101 is picked up and transported to the transport roller 108 located diagonally below the paper feed roller 101, and the paper is further upstream by the transport roller 108. Side.

In this paper feeding section, FIG.
As shown in (a) and (b), the concave portion 10 which is a U-groove portion
2a, the protrusion 101a of the paper feed roller 101 is fitted,
In this state, the sheet feeding roller 10
7A, the protrusion 101b is fitted into the recess 102b, whereby the portion C of the sheet feeding roller support plate 102 in FIG.
b is snap-fitted, and the paper feed roller 101 is fixed to the paper feed roller support plate 102. On the other hand, when removing the feed roller 101 from the feed roller support plate 102 for cleaning or replacement, the feed roller support plate 10
Lift the C part of 2 and remove the snap fit,
By rotating in the direction of arrow F in FIG.
What is necessary is just to cancel the fitting of 2a and the protrusion part 101a.

However, in the conventional image forming apparatus provided with the paper feed unit, it is necessary to purchase a predetermined solvent such as alcohol when cleaning the removed paper feed roller 101, and when replacing the paper feed roller 101 with a new one. In such a case, it is necessary to order a paper feed roller 101 as a replacement part from a manufacturer.
At this time, the image forming apparatus cannot be used until the solvent is purchased or a replacement part is obtained. Further, the paper feed roller 101 after replacement is discarded, and does not have a favorable effect on the environment.

The present invention has been proposed in order to solve the above-mentioned problem. Even when the paper feed roller needs to be replaced, the user does not need to purchase the paper feed roller immediately. It is another object of the present invention to provide a sheet material feeding apparatus and an image forming apparatus capable of reducing adverse effects on the environment.

[0014]

In order to solve the above-mentioned problems, a sheet feeding apparatus according to the present invention has a sheet holding portion for stacking and holding sheet materials, and a holder rotatably disposed near the sheet holding portion. A base portion, and a sheet feeding roller having a sheet feeding surface for feeding the sheet material from the sheet holding portion and detachably held by the holder base portion, wherein a plurality of sheet feeding rollers having the same shape are provided. Characterized in that it has a sheet feeding / conveying surface.

In the sheet feeding apparatus of the present invention, the sheet feeding roller has a plurality of sheet feeding / conveying surfaces of the same shape. By removing the paper roller from the holder base and attaching it to the holder base as a position to use another paper transport surface, it is possible to use another paper transport surface without replacing it with a new paper feed roller Becomes

The shape of the paper feed roller is, for example, a substantially elliptical outer shape, and a pair of paper feed conveyance surfaces having the same shape are formed at a boundary of a straight line passing through two fixed points of the ellipse. In this case, the sheet feeding roller is held by the holder base so that one of the sheet feeding and conveying surfaces is exposed, so that even if one of the sheet feeding and conveying surfaces becomes unusable due to wear or the like, the sheet feeding roller can be held in the holder. By detaching from the base portion and making a half turn in a predetermined direction, and then attaching it to the holder base portion again, it is possible to use the other sheet feeding and conveying surface without replacing it with a new sheet feeding roller.

The holder base is provided with a pair of plate-like elastic members sandwiching both ends of the sheet feeding roller, and both ends of the sheet feeding roller and each plate-like elastic member can be detachably attached to both ends of the sheet feeding roller. Is provided with a locking mechanism for locking and holding.

In this locking mechanism, the first projections formed on the same plane on both ends of the paper feed roller and on a straight line passing through two fixed points of the ellipse, and the respective first projections are fitted. And a pair of first concave portions. Thus, the paper feed roller rotates about each of the first protrusions in a state where each of the first protrusions and each of the first recesses are fitted to each other, whereby the paper feed roller can be attached to and detached from each plate-like elastic member. Will be

At the time of attachment / detachment, the sheet feeding roller is detached from each plate-like elastic member, is rotated by a half turn in a predetermined direction, and is attached to each plate-like elastic member. Since both ends of the paper roller are sandwiched and the other sheet feeding / conveying surface of the roller member is exposed, it is possible to set the sheet so as to use the other sheet feeding / conveying surface.

Further, in order to solve the above problems, the image forming apparatus of the present invention comprises a sheet feeding means for feeding a sheet material to an image forming means for forming an image on the sheet material, wherein the sheet feeding means comprises: A sheet holding unit for stacking and holding sheet materials,
A holder base portion rotatably arranged in the vicinity of the sheet holding portion, and a sheet feeding roller having a sheet feeding conveyance surface for feeding a sheet material from the sheet holding portion and detachably held by the holder base portion. And the sheet feeding roller has a plurality of sheet feeding and conveying surfaces having the same shape.

In the image forming apparatus of the present invention, since the paper feed roller has a plurality of paper feed / conveying surfaces having the same shape, even if one of the paper feed / conveying surfaces becomes unusable due to wear or the like,
By removing the paper feed roller from the holder base and attaching it to the holder base as a position to use another paper transport surface, it is possible to use another paper transport surface without replacing it with a new paper feed roller. It becomes possible.

The shape of the paper feed roller is, for example, a substantially elliptical outer shape, and a pair of paper feed conveyance surfaces having the same shape are formed at a boundary of a straight line passing through two fixed points of the ellipse. In this case, the sheet feeding roller is held by the holder base so that one of the sheet feeding and conveying surfaces is exposed, so that even if one of the sheet feeding and conveying surfaces becomes unusable due to wear or the like, the sheet feeding roller can be held in the holder. By detaching from the base portion and making a half turn in a predetermined direction, and then attaching it to the holder base portion again, it is possible to use the other sheet feeding and conveying surface without replacing it with a new sheet feeding roller.

Further, the image forming apparatus of the present invention has an image forming means accommodating space for accommodating the image forming means in a removable manner, and the paper feed roller has the image forming means accommodated in the image forming means accommodating space. Is located adjacent to the
The image forming means is attached to and detached from the holder base through the removed image forming means storage space.

With this configuration, in the image forming apparatus, after the image forming unit is taken out, the sheet feeding conveyance surface used by the sheet feeding roller can be easily replaced via the image forming unit storage space. become.

[0025]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a laser beam printer 10 (hereinafter, printer 1) using a detachable process cartridge 1 as an example of an image forming apparatus according to the present invention.
(Abbreviated as 0). The transport direction of the recording paper P is
In FIG. 1, the right side is the upstream side, and the left side is the downstream side. As the recording paper P, in addition to general plain paper, special paper such as cardboard, envelopes, and other sheet materials such as OHT films other than paper can be used. The case where ordinary plain paper is used will be described.

The printer 10 is arranged vertically or vertically on the upstream side (in the right side of FIG. 1 and behind the main body 2) of the printer main body 2 (hereinafter simply referred to as "main body 2") in the recording paper feeding direction. A paper feed tray 3 for stacking and supporting a plurality of recording papers P before image formation is provided, and the recording papers P after image formation are vertically supported downstream of the main body 2 (front side of the main body 2). A discharge tray 4 is provided.

The printer 10 transports the lower end of the paper feed tray 3 and the lower end of the paper discharge tray 4 extending from right to left of the main body 2 as viewed in FIG. A paper feed unit 5, a process cartridge 1, a transfer unit 6, a fixing unit 7, a paper discharge roller pair 8, and the like are provided from the upstream side along the transport path. Further, in the printer 10, a small U-shaped path (hereinafter, abbreviated as a vertical U-shaped path) is configured as a whole by arranging the sheet feeding unit 5, the process cartridge 1, and the fixing unit 7 as close as possible. ing.

The process cartridge 1 used in the printer 10 integrates at least developing means having a photosensitive drum 1A as an image carrier on which an electrostatic latent image is formed by an electrophotographic method, a developing sleeve 1B, and the like. The image processing means such as the charging means 1 </ b> C is integrated as necessary, and is detachable from the main body 2.

A main body frame 11 as a housing part has a bottom plate 12 on which the electric component part 9 is mounted and a top plate on which a laser scanner 13 for forming a latent image on the photosensitive drum 1A of the process cartridge 1 is mounted. 14, a left and right side plate (not shown), and a stay member 15 located at the center of the main body 2. On the stay member 15, various members such as a transfer section 6, a fixing section 7, and a transport guide section 16 serving as a transport path of the recording paper P from the transfer section 6 to the fixing section 7 are mounted.

The process cartridge 1 includes a discharge tray 4
The open / close cover 18 having the shape shown in FIG. 2 is moved from the position indicated by the two-dot chain line to the position indicated by the solid line, and is opened. Inserted and held in place. In the printer 10, a switch (not shown) is interlocked with opening and closing of the opening and closing cover 18.
When the cover 18 is opened, the main power of the main body 2 is turned off, and when the cover is closed, the main power of the main body 2 is turned on.

Further, in the printer 10, when the open / close cover 18 is opened and the process cartridge 1 is taken out, a paper feed roller 20 is provided at the center of the paper feed unit 5 on the back side thereof. The paper feed roller 20 of the paper feed unit 5 is provided at a position where the process cartridge 1 can be easily accessed and touched via the cartridge storage unit S when the process cartridge 1 is taken out.

In the printer 10, the process cartridge 1 is inserted, the open / close cover 18 is closed, and when the process cartridge 1 and the open / close cover 18 are at the positions indicated by the two-dot chain lines in FIG. In this state, an operation is started by connecting a power cord (not shown) and further connecting to a host computer such as a personal computer and transmitting a signal from the host computer. Here, in the printer 10, a laser beam is emitted from the laser scanner 13 to form an electrostatic latent image on the photosensitive drum 1A of the process cartridge 1. Only one sheet of recording paper P, which is a transfer material for transferring the image, is picked up from the paper feed tray 3 by the paper feed roller 20 of the paper feed unit 5 and is conveyed to the transfer unit 6.

More specifically, in the paper supply section 5, when a paper supply roller shaft 21, which will be described in detail later, is rotated clockwise in FIG. The above-described paper feed roller support plate and the paper feed roller 20 supported by the paper feed roller support plate rotate integrally, and pick up only one recording paper P from the paper feed tray 3. Is transported to a roller 22 disposed diagonally below the paper feed roller 20.

Then, the recording paper P is conveyed by the conveying roller 22 of the paper feeding unit 5 to the transfer unit 6 for transferring the toner image formed on the photosensitive drum 1A,
The toner image is transferred to the surface of the recording paper by the nip between A and the transfer roller, and further conveyed to the fixing unit 7.
In the fixing unit 7, the recording paper P passes through a nip between the pressure roller heated by the heater and the heater, so that the toner on the surface of the recording paper is melted and fixed on the recording paper P. Then, the recording paper P is conveyed to the paper discharge unit, discharged onto the paper discharge tray 4 by the paper discharge roller pair 8, and sequentially stacked.

Next, the configuration of the paper feed unit 5 in the printer 10 will be described in detail. As shown in FIG. 2, the sheet feeding unit 5 includes an intermediate plate 23 that presses the recording sheet P against the sheet feeding roller 20.
And a friction separating member 24 that separates the recording paper P one by one by a frictional force, a transport roller 22, and an opposing driven roller 25 positioned opposite to the roller 22, and these transfer the recording paper P to the transfer unit. 6 is formed.

Further, as shown in FIG. 3, the paper feed section 5 is connected to a paper feed roller shaft 21 mounted near each member constituting the transport section by a coupling with the paper feed roller shaft 21. Shaft portion 31, a pair of paper feed rollers 33 (33 a, 33 b) and a pair of paper feed rollers 33
A pair of paper feed roller support plates 34 (34
a, 34b) and the feed roller support plate 34 (34a, 34a).
34b), a pair of holding members 32 (32a, 32b) that rotatably hold these members, and a middle plate 2 of the transport unit.
3 is provided with a cam 35 provided on the paper feed roller shaft 21 for pushing down the feed roller 3, and a paper feed gear unit 36 with a toothless gear for controlling the cam 35 to make one rotation. In the paper feed unit 5, the paper feed roller 20 is located at the center position (substantially at the center of the paper width) of the recording paper P pressed by the middle plate 23.

The paper feed roller holding member 14 of the paper feed unit 5 is a fixed member attached to the main body frame 11, and rotates with the shaft 31 and each paper feed roller 33 as the paper feed roller shaft 21 rotates.
(33a, 33b), each paper feed roller support plate 34 (34
a, 34b), and each of these members is held so as to rotate the paper feed roller 20 in the direction D in FIG. 2, and a pair of holding members 3 for holding these members rotatably.
2 (32a, 32b). Each of the holding members 32 also has a function as a guide member for guiding the recording paper P separated by the friction separating member 24 and the paper feed roller 20 in FIG. As shown in FIG. 2, each holding member 32 also has a function as a holder for holding the opposing driven roller 25 of the roller 22. And the recording paper P
When the feed roller shaft 21 is driven to rotate as described above, only one sheet is picked up from the feed tray 3 by the rotation of the feed roller 20 as a unit. It is conveyed to the arranged roller 22.
At this time, the recording paper P is guided by each holding member 32 toward the image forming portion of the process cartridge 1.

Next, the configuration of the paper feed roller 20 of the paper feed unit 5 will be described.
Further, the paper feed roller 20 and each paper feed roller support plate 34 (34
a, 34b) will be described. As shown in FIG. 2C, the paper feed roller 20 includes a rubber part 41 as a roller member made of a high friction material, and a metal core part 42 as a holder to which the rubber part 41 is attached. Here, the rubber part 41 has a cylindrical shape, and the metal core part 42 has a cylindrical or cylindrical shape having a substantially elliptical cross section. The paper feed roller 20 with the rubber portion 41 attached to the cored bar portion 42 has a substantially elliptical outer shape, and a straight line passing through two fixed points of the ellipse (hereinafter, referred to as a straight line).
It is called the major axis. On the roller surface of the rubber portion 41, a pair of and the same-shaped sheet feeding / conveying surfaces 43 and 44 are formed. That is, the feed roller 20 has a substantially elliptical cross-sectional shape, the rubber portion 41 has a symmetric shape with respect to the major axis, and the feed conveyance surfaces 43 and 44 have the same shape.

A first projection 45 for positioning is formed on the sheet feeding roller 20 on the same plane view on both sides (both ends) of the cored bar 42 (see FIG. 3). Specifically, the first protruding portion 45 is configured such that the paper feed roller 20
Is provided in the vicinity of a portion A (hereinafter, referred to as a sheet feeding front end portion A) which comes into contact with the recording paper P first after rotating in the direction D and on the major axis. The first protrusion 45 has, for example, a pin shape (columnar protrusion) as shown in the figure, and the major axis passes through the center of the shape.

The paper feed roller 20 has second protrusions 46 and 47 and a third protrusion 4 on both end sides of the cored bar 42.
8 are formed. More specifically, it is in the vicinity of the last part B (hereinafter, referred to as a paper feed rear end B) of contact with the recording paper P when the paper feed roller 20 rotates in the direction D in FIG. A third projection 48 is provided on the major axis. On the other hand, the second protrusions 46 and 47 are as shown in FIG.
As shown in the figure, the third projections 48 are provided near the right side of each of the third projections 48 with respect to the center of the ellipse. Second
It is preferable that the projecting portion 46 is a square projection having a vertical surface on the circumferential side (closer to the rubber portion 41) and an inclined surface on the long axis side. The third projection 48 is, for example, a prismatic projection as shown in the drawing, and the major axis passes through the center. These first, second, and third projections 45, 46, 48
The paper feed roller 20 is connected to the roller support member 34 (34a, 3
4b) function as first, second and third locking means for locking.

In the sheet feeding section 5, the sheet feeding roller shaft 2 shown in FIG.
1 with a coupling or the like, or the paper feed roller shaft 21
A pair of paper feed roller support plates 34 (34a, 34b) shown in FIG. Each of the paper feed roller support plates 34a and 34b is a plate-like elastic member. Then, each of the paper feed tip portions A of the pair of paper feed roller support plates 34 (34a, 34b)
On the side, a first concave portion 51 (FIG. 2C), which is a groove into which the first protrusion 45 of the paper feed roller 20 is fitted, is formed.

The second protrusions 46 and 47 of the paper feed roller 20 are provided on the paper feed rear end B side of the paper feed roller support plate 34b.
The second concave portion 52 that engages with either one of them is provided. The second concave portion 52 has, for example, a square hole shape as shown in FIG.

Thus, in the paper feed unit 5, when the paper feed roller 20 is inserted between the pair of paper feed roller support plates 34 (34a, 34b), the second protrusion 4
6 and the second concave portion 52 provided on the side of the feed roller support plate 34b are engaged with each other and snap-fit. As shown in FIG. 2, the paper feed roller support plate 34b is designed so that the C portion of the paper feed roller support plate 34b is easily elastically deformed when the second locking means is snap-fit.
A groove 53 is provided near the second recess 52.

Further, each paper feed roller support plate 34a, 34
At the position of the rear end portion B of the sheet feeding portion b, a contact portion 54 is provided as a third concave portion, which abuts against the third projecting portion 48 of the sheet feeding roller 20 (see FIG. 4). In the paper feeding unit 5, the third projection 48 and the abutment 54 constitute a third locking unit.

As described above, the first to third locking mechanisms are used as the locking mechanism.
In the sheet feeding section 5 provided with the locking means,
When attaching the first projections 45 to the respective feed roller support plates 34 (34a, 34b), first, the first projections 45, which are the first locking means, and the first recesses 51 are fitted together. The state is as shown in FIG. Then, by rotating the paper feed roller 20 counterclockwise as viewed from FIG. 2B from this state, the second protrusion 46 on the paper feed roller 20 side contacts the paper feed roller support plate 34b side. Contact, paper feed roller support plate 3
After the portion C of FIG. 4b is elastically deformed, the second protrusion 46 and the second
And the concave portion 52 is snap-fitted into a state as shown in FIG. In this case, the paper feed roller 2
The third protruding portion 48 on the 0 side is provided with the respective feed roller support plates 34a,
The sheet feed roller 20 with respect to each of the sheet feed roller support plates 34a and 34b is abutted against the abutting portion 54 of the sheet feed roller 34b.
Is performed.

More specifically, the position of the sheet feeding roller 20 in the direction E in FIG. 2A with respect to the sheet feeding roller support plate 34 (34a, 34b) is determined by the first protrusion 45 and the first recess 5.
1. The second protrusion 46 and the second recess 52 to be snap-fitted, and the third protrusion 48 and the butting portion 54 are used. The positioning in the direction of arrow G in FIG.
This is performed by fitting the width direction of the second protrusion 46 with the width direction of the square hole of the second recess 52. The paper feed roller 20 thus mounted is mounted in the same manner as in the conventional example of FIG. 7, and the mounting position is stabilized.

FIG. 4 shows the states of the sheet feeding roller 20 corresponding to FIGS. 2A to 2C from the opposite direction to FIG. 2, and FIG. FIG. 4 shows a state in which is attached to the feed roller support plate 34 (34a).
FIG. 4B shows a state in which the paper feed roller 20 is being removed from the paper feed roller support plate 34a, and FIG. 4C shows a state in which the paper feed roller 20 is removed from the paper feed roller support plate 34.
Each is shown.

As is apparent from a comparison between FIG. 2 and FIG. 4, the paper feed roller 20 in this embodiment is provided with the first protrusion 45 in the same position and in the same shape (to penetrate). The third protrusion 48 is also provided at the same position and in the same shape. On the other hand, the second protrusion 4
The second protrusion 47 formed on the opposite side of the sheet feed roller 6 is not at the same position but at a position on the opposite side that is line-symmetric with respect to the major axis of the paper feed roller 20, in other words, rotates with respect to the major axis. They are provided at symmetrical positions.

Further, as for the feed roller support plate 34a of FIG. 4 which is located on the opposite side of the feed roller support plate 34b of FIG. 2, the first concave portion 51 is provided in the same position and in the same shape.
The abutment portion 54, which is the third concave portion, is also provided in the same portion in the same shape. On the other hand, in the sheet feeding roller support plate 34a of FIG. 4, the member is cut out at a portion F in FIG. 4B, and a concave portion corresponding to the second concave portion 52 is not provided. Accordingly, the second protrusion 47 does not snap-fit on the side of the paper feed roller support plate 34a.

In order to remove the paper feed roller 20, FIG.
When the process cartridge 1 is taken out by opening the opening / closing cover 18 of the cartridge storage unit S from the discharge unit side,
To make the paper feed roller 20 accessible. 2 (a) and 4 (a) while releasing the snap-fit of the second locking means by pushing outward the C portion of one of the sheet feeding roller support plates 34b shown in FIG. 2) from the state shown in FIG.
(A) By rotating in the direction D, the locked state of the second locking means and the third locking means is released, as shown in FIGS. 2 (b) and 4 (b). Finally, by releasing the engagement of the first locking means, it is possible to obtain the state shown in FIGS.
As shown in (c), the paper feed roller 20 can be removed from each paper feed roller support plate 34 (34a, 34b).

Here, the sheet feeding unit 5 in this embodiment
2C and 4C, the paper feed roller 20 is rotated by half a rotation along its major axis and attached to each paper feed roller support plate 34 to supply the roller surface to be used. The paper transport surface 43 can be changed to the paper transport surface 44.
That is, when the paper feed roller 20 is rotated half a rotation along the major axis from the state shown in FIG.
The first projection 45 and the third projection 48 on the side (FIG. 4C) come to the positions shown in FIG. 2C, respectively.
2C) is located at the position of the second protrusion 46 shown in FIG. 2C.
By attaching 0 to each paper feed roller support plate 34 in the above-described procedure, the roller surface to be used can be changed from the paper feed transport surface 43 to the paper feed transport surface 44. Therefore, according to the image forming apparatus provided with such a sheet feeding unit 5, even if one sheet feeding and conveying surface becomes unusable due to abrasion or the like, the other sheet feeding and conveying surface can be replaced without replacing the sheet feeding roller. Since the paper feed roller can be used, the paper feed roller can be used for a longer period of time, and adverse effects on the environment can be reduced.

In this embodiment, each projection 45,
46, 47, and 48 are provided on the paper feed roller 20 side, and each recess 5 is provided.
1, 52 and 54 are provided on the feed roller support plate 34 side. However, the opposite configuration is adopted, ie, each projection is provided on the feed roller support plate 34 side, and each concave portion is provided on the feed roller 20 side. Or a configuration in which only a specific protrusion is provided on the paper feed roller support plate 34 side and a corresponding concave portion is provided on the paper feed roller 20 side.

Next, another embodiment of the paper feed roller and the paper feed roller support plate applied to the printer 10 shown in FIG. 1 will be described with reference to FIGS. The same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

The paper feed roller 60 in the paper feed unit 5A shown in FIG. 5 has a rubber part 61 as a roller member made of a high friction material and the rubber part 61 is attached, similarly to the case of the paper feed roller 20 in FIG. And a metal core 62 as a holder. Here, the rubber portion 61 has a cylindrical shape, and the metal core portion 62 has a substantially elliptical cylinder or column shape in cross section. The paper feed roller 60 in a state where the rubber portion 61 is attached to the metal core portion 62 has a substantially elliptical outer shape, and is separated from the rubber portion 61 by the long axis passing through two fixed points of the ellipse. And a pair of the same-shaped sheet feeding / conveying surfaces 63 and 64 are formed on the roller surfaces.

The first and second protrusions 65 and 68 for positioning are also of the same shape and symmetrical with each other on the both ends of the cored bar 62 when viewed in the same plane. Is formed at the position. Specifically, the first protrusion 65
The paper feed roller 60 is provided in the vicinity of the paper feed front end portion A where the paper feed roller 60 rotates in the direction H in FIG. On the other hand, the third protruding portion 68 is provided near the paper feeding rear end portion B where the paper feeding roller 60 rotates in the direction H in FIG. ing. The first projection 65 and the third projection 68 are, for example, pin-shaped as shown, and the major axis passes through the center. That is, the first
The third protrusion 68 is disposed at a point symmetrical position on the same plane with respect to the center point of the elliptical shape.

As shown in FIG. 5C, two second protrusions (66, 67) are formed on one end surface of the cored bar 62 in the paper feed roller 60. Specifically, the second
As shown in FIG. 5 (c), the projections 66 and 67 of the first projection 65 have first projections 65 with respect to the center point of the ellipse.
And near the right side of the third protrusion 68. It is preferable that each of the second protrusions 66 and 67 be a square protrusion having a vertical surface on the circumferential side (closer to the rubber portion 61) and a slope on the long axis side.

In this way, as shown in FIG. 5C, the sheet feeding roller 60 in this embodiment is such that each projection of the cored bar 62 is on the same plane with respect to the center point of the elliptical shape. Are arranged at point-symmetric positions. The first, second, and third projections 65, 66, 67, 68
Function as first, second and third locking means for locking the paper feed roller 60 to the roller support plate 70, respectively. In this embodiment, the first protrusion 6
Since the fifth and third protrusions 68 are arranged in the same shape and symmetrical positions with each other, the first protrusion 65 also functions as a third locking means, and the third protrusion 68 is the first protrusion 68. Will also function as locking means.

On the other hand, a pair of feed roller support plates 70 (70
a, 70b) include the feed roller support plate 34 shown in FIG.
Similarly to (34a, 34b), the first concave portion 71, the second concave portion 72, the groove portion 73, and the third concave portion 74 are respectively formed by the first concave portion 51 and the third concave portion of the sheet feed roller support plate 34 in FIG. The second recess 52, the groove 53, and the third recess 54 are formed in the same location and in the same shape. Further, a fourth concave portion 75 is formed in the pair of feed roller support plates 70. The fourth concave portion 75 is a portion for avoiding the abutment of the second protrusion 66 or 67 of the paper feed roller 60 and avoiding snap fitting, and is located on the back side (the side in contact with the paper feed roller 60) in FIG. The main surface has a concave shape.

As described above, in the paper feeding section 5A having the first to third locking means as the locking mechanism, when the paper feeding roller 60 is attached to each paper feeding roller support plate 70,
First, the first projection 65, which is the first locking means, and the first concave portion 71 are fitted to each other, and a state as shown in FIG. 5B is obtained. Then, from this state, the paper feed roller 60 is
By rotating counterclockwise as viewed from (b), the second protrusion 66 on the paper feed roller 60 abuts on the paper feed roller support plate 70 side, and the paper feed roller support plate 70 is elastically deformed. Later, the second protrusion 66 and the second recess 72 are snap-fitted to each other, resulting in a state as shown in FIG.
At this time, the third protrusion 68 on the paper feed roller 60 side is brought into contact with the abutting part 74 on the paper feed roller support plate 70 side, so that the paper feed roller 60 Is performed.

More specifically, the position of the sheet feeding roller 60 in the direction K in FIG. 5A with respect to the sheet feeding roller supporting plate 70 is snap-fitted between the first projection 65 and the first recess 71. The second protrusion 72-1 and the second recess 72, and the third protrusion 68 and the butting portion 74 are used. The positioning in the direction of arrow L in FIG.
And the width direction of the square hole of the second recess 72 is fitted. The paper feed roller 60 thus mounted is mounted similarly to the conventional example of FIG. 7, and the mounting position is stabilized.

On the other hand, when removing the paper feed roller 60, the process cartridge 1 is taken out by opening the opening / closing cover 18 shown in FIG. Make it reachable. Then, the sheet feeding roller 60 is fed from the state shown in FIG. 5A while the snap-fit of the second locking means is released by expanding the portion C in FIG. By gripping the rear end portion B and rotating it in the H direction in FIG. 5A, the locked state of the second locking means and the third locking means is released as shown in FIG. 5B. You. Finally, by releasing the engagement of the first locking means, the paper feed roller 60 can be removed from the paper feed roller support plate 70 as shown in FIG.

Here, the sheet feeding unit 5 in this embodiment
5A, the paper feed roller 60 is attached to the paper feed roller support plate 70 by rotating the paper feed roller 60 from the state shown in FIG. The roller surface to be used can be changed from the sheet feeding / conveying surface 63 to the sheet feeding / conveying surface 64. That is, when the paper feed roller 60 is rotated half a turn from the state shown in FIG.
The second projection 66 and the third projection 68 on the same surface side (FIG. 5 (c) side) correspond to the second projection 67 and the first projection 65 shown in FIG. 5 (c), respectively. In this state, by attaching the paper feed roller 60 to the paper feed roller support plate 70 in the above-described procedure, the roller surface to be used can be changed from the paper feed / conveyance surface 63 to the paper feed / conveyance surface 64. Becomes Therefore, according to the image forming apparatus provided with such a paper feeding unit 5A, even if one of the paper feeding and conveying surfaces becomes unusable due to wear or the like, the other paper feeding and conveying surface can be replaced without replacing the paper feeding roller. Since it can be used, the paper feed roller can be used longer. In this embodiment, when the paper feed conveyance surface is changed, one end of the paper feed roller 60 which was the paper feed front end becomes the paper feed rear end, and the other end which was the paper feed rear end is used. Side is the leading end of the paper feed.
Further, in the paper feeding unit in this embodiment, the rotation direction of the paper feeding roller 60 is constant even when the paper feeding / conveying surface is exchanged, so that the paper feeding unit is preferably used even when the surface of the rubber portion 61 is polished and used. it can.

In this embodiment, the second projections (66, 67) are provided only on one end face of the paper feed roller 60. However, the present invention is not limited to this.
As shown in FIG. 2, the second protrusion (76,
77) may be provided. With such a configuration,
As in the case of the paper feed roller 20 described with reference to FIGS. 2 to 4, it is also possible to change the paper feed conveyance surface while maintaining the positional relationship between the paper feed front end and the paper feed rear end. It is possible to change the paper feed conveyance surface according to the state of wear of the paper. When the paper feed roller 60 has such a configuration,
The sheet feeding roller support plate 70a located on the opposite side to FIG. 5 does not snap-fit to the second protrusion of the sheet feeding roller 60 in addition to the shape of the portion F in FIG. 4B. The fourth recess 75 may be provided.

In this embodiment, each projection 65,
66, 67, 68 are provided on the side of the paper feed roller 60,
1, 52 and 54 are provided on the feed roller support plate 70 side, but the opposite configuration is adopted, that is, each projection is provided on the feed roller support plate 70 side, and each concave portion is provided on the feed roller 60 side. Alternatively, only a specific protrusion may be provided on the paper feed roller support plate 70 side, and a corresponding concave portion may be provided on the paper feed roller 60 side.

Further, in this embodiment, the paper feed roller has a substantially elliptical outer shape (cross-sectional shape) and is provided with a pair of paper feed conveyance surfaces of the same shape. However, the present invention is not limited to this, and it is sufficient if the sheet has a plurality of sheet feeding and conveying surfaces having the same shape. Therefore, the paper feed roller may have a substantially triangular outer shape (cross-sectional shape) and three paper feed / conveying surfaces of the same shape.

[0066]

As described in detail above, according to the sheet feeding apparatus and the image forming apparatus of the present invention, since the sheet feeding roller has a plurality of sheet feeding and conveying surfaces having the same shape as each other, any one of the sheet feeding rollers has the same shape. Even if the paper feeding and transporting surface becomes unusable due to wear, etc.,
By removing the paper feed roller from the holder base and attaching it to the holder base as a position to use another paper transport surface, it is possible to use another paper transport surface without replacing it with a new paper feed roller. It becomes possible. Accordingly, it is not necessary to immediately replace the paper feed roller with the insufficient frictional force with a new one or to wash it with a solvent, so that maintenance becomes very easy. Also, the maker can reduce the inventory of service parts, which can contribute to suppressing the deterioration of the global environment.

Further, by providing a snap-fit portion in the locking mechanism between the sheet feeding roller and the holder base, the attachment / detachment and positioning of the sheet feeding roller and the holder base can be performed by a simple operation.

Further, according to the image forming apparatus of the present invention, the image forming means has an image forming means housing space for accommodating the image forming means so that the image forming means can be taken out. The image forming device is disposed at a position adjacent to the forming device and is configured to be attached to and detached from the holder base portion through the image forming device storage space from which the image forming device is taken out. It is possible to easily exchange the paper feed conveyance surface used by the paper feed roller via the storage space. Therefore, when the user determines that one of the sheet feeding and conveying surfaces cannot be used for the sheet feeding roller, it can be easily and promptly replaced with another sheet feeding and conveying surface, thereby improving maintenance.

[Brief description of the drawings]

FIG. 1 is a main sectional view showing a schematic configuration of an image forming apparatus to which the present invention is applied.

FIGS. 2A and 2B are diagrams illustrating a sheet feeding roller in the image forming apparatus of FIG. 1, wherein FIG. 2A illustrates a state in which the sheet feeding roller is attached to a sheet feeding roller support plate (holder base portion), and FIG. (C) shows a state in which the paper feed roller is being removed from the paper feed roller support plate, and (c) shows a state in which the paper feed roller is removed from the paper feed roller support plate.

FIG. 3 is a front view for explaining a mechanism for rotating a sheet feeding roller.

FIGS. 4A and 4B are diagrams showing states of a sheet feeding roller corresponding to FIGS. 2A to 2C from a direction opposite to FIG. 2, and FIG. (B) shows a state in which the paper supply roller is being removed from the paper supply roller support plate, and (c) shows a state in which the paper supply roller is removed from the paper supply roller support plate. .

5A and 5B are diagrams illustrating another embodiment of the sheet feeding roller and the sheet feeding roller supporting plate, wherein FIG. 5A illustrates a state in which the sheet feeding roller is attached to the sheet feeding roller supporting plate, and FIG. (C) shows a state in which the paper roller is being removed from the paper supply roller support plate, and (c) shows a state in which the paper supply roller is removed from the paper supply roller support plate.

FIG. 6 is a front view for explaining a mechanism for rotating a sheet feeding roller in FIG. 5;

7A and 7B are extraction diagrams of a main part of a paper feeding unit in a conventional image forming apparatus, wherein FIG. 7A illustrates a state in which a paper feeding roller is attached to a paper feeding roller support plate, and FIG. 7 shows a state in which the sheet is being removed from the paper roller support plate.

[Explanation of symbols]

Reference Signs List 10 laser beam printer P recording paper 1 process cartridge 2 printer body 3 paper feed tray 4 discharge tray 5, 5A paper feed unit 5 Transfer unit 6 Fixing unit 11 Main body frame 18 Opening / closing cover S Cartridge storage unit 20, 60 Feed roller 21 Feed roller shaft 22 Conveying rollers 23 Middle plate 24 Friction separating member 25 Opposite driven roller 31 Shaft 32 (32a, 32b) Holding member 33 (33a, 33b) Feeding Rollers 34 (34a, 34b), 70 (70a, 70b) ...
Paper feed roller support plate (holder base part) 41, 61 ... Rubber part 42, 62 ... Core part 43, 44, 63, 64 ... Paper feed surface A ... Paper feed tip B .., Sheet feeding rear end portions 45, 65 first projection portions 46, 47, 66, 67, 76, 77 second projection portions 48, 68 third projection portion 51 , 71 ... First recess 52, 72 ... Second recess 53, 73 ... Groove 54, 74 ... Abutment (third recess) 75 ... Fourth recess

Claims (39)

[Claims] 1. A sheet holding portion for stacking and holding sheet materials, a holder base portion rotatably arranged in the vicinity of the sheet holding portion, and a sheet feeding and conveying surface for feeding the sheet materials from the sheet holding portion. And a sheet feeding roller detachably held by the holder base portion, wherein the sheet feeding roller has a plurality of sheet feeding and conveying surfaces having the same shape as each other. 2. The sheet feeding roller has a substantially elliptical outer shape, and a pair of sheet feeding and conveying surfaces having the same shape are formed at a boundary of a straight line passing through two fixed points of the ellipse, and one of the sheet feeding and conveying surfaces is formed. The sheet material feeding device according to claim 1, wherein the sheet material feeding device is held by the holder base so as to be exposed. 3. The holder base portion includes a pair of plate-like elastic members sandwiching both end surfaces of the sheet supply roller, and the sheet supply member is formed by both end surfaces of the sheet supply roller and each plate-like elastic member. 3. The sheet feeding device according to claim 1, wherein a locking mechanism for detachably locking and holding both end surfaces of the roller is configured. 4. A pair of first projections formed on the same side view of both end surfaces of the sheet feeding roller at the sheet feeding front end and on a straight line passing through the two fixed points of the elliptical shape. And a pair of first recesses formed on each of the plate-like elastic members and fitted with each of the first protrusions. Rotation about the first projections in a state where the first projections and the first recesses of the locking means are fitted to each other, whereby the attachment / detachment to / from each of the plate-like elastic members is performed. Claim 3 characterized by the following:
The sheet material feeding device according to the above. 5. The locking mechanism removes the paper feed roller from each of the plate-like elastic members, and rotates the paper feed roller by a half rotation about a straight line passing through the two fixed points of the ellipse to thereby make the respective paper feed rollers half-rotated. 5. The sheet feeding device according to claim 4, wherein the sheet feeding roller is attached to the sheet-shaped elastic member so that both ends of the sheet feeding roller are sandwiched between the plate-shaped elastic members, and the other sheet feeding and conveying surface is exposed. . 6. The first locking means of the locking mechanism,
The sheet material according to claim 5, wherein each of the first protrusions is provided on both end surfaces of the sheet feeding roller, and each of the first recesses is provided in each of the plate-like elastic members. Feeding device. 7. The locking mechanism according to claim 3, wherein the locking mechanism includes a snap-fit portion in which the paper feed roller is snap-fitted to each of the plate-shaped elastic members. The sheet material feeding device according to the above. 8. The snap-fit part of the locking mechanism,
8. A second locking means comprising a second projection and a second recess fitted with the second projection.
The sheet material feeding device according to the above. 9. The second locking means, wherein the second projection is provided on at least one end face of the paper feed roller, and the second recess is provided on each of the plate-like elastic members. The sheet material feeding device according to claim 8, wherein the sheet material feeding device is provided on at least one of the plate-like elastic members. 10. The sheet according to claim 9, wherein a groove is formed near the second recess in the plate-like elastic member to facilitate deformation near the second recess. Material feeding device. 11. The first projection is a pin-shaped projection, the second projection is a square projection, and one end of the first recess is open to the outer periphery of the plate-shaped elastic member. The sheet feeding device according to any one of claims 7 to 10, wherein the groove is a groove, and the second concave portion is a rectangular concave portion corresponding to the rectangular protrusion. 12. The second locking means in the second locking means.
A pair of protrusions are formed on both end surfaces on the rear end side of the sheet feeding roller at positions that are rotationally symmetric with respect to a straight line passing through the two fixed points of the ellipse. 12. The sheet feeding device according to any one of 9 to 11. 13. The second locking means, wherein the second concave portion is provided only on one plate-like elastic member, and the other plate-like elastic member has a snap fit with the second protrusion. 13. A notch which is not formed is provided.
The sheet material feeding device according to the above. 14. The second locking means in the second locking means.
13. A pair of the protrusions are formed on the same end face side of the paper feed roller at positions that are point-symmetric with respect to the center point of the elliptical shape, respectively. The sheet material feeding device according to the above. 15. The device according to claim 15, wherein the locking mechanism includes a third protrusion provided near the second protrusion and a third recess configured to lock the third protrusion. The sheet material feeding device according to any one of claims 8 to 14, further comprising a locking means. 16. A third locking means in the locking mechanism, wherein the third projection is provided on the paper feed roller side,
The sheet feeding device according to claim 15, wherein the third concave portion is provided in at least one of the plate-like elastic members. 17. The third locking means in the third locking means.
17. The sheet feeding apparatus according to claim 16, wherein the concave portion has a contact portion that abuts the third protrusion when the sheet feed roller is attached to each of the plate-shaped elastic members. 18. The third locking means in the third locking means.
18. The sheet material feeding device according to claim 16, wherein the projection is formed on a straight line passing through the two fixed points of the ellipse. 19. The locking mechanism, wherein the third protrusion has the same shape as the first protrusion, the feed roller is removed from each of the plate-like elastic members, and the feed roller is half By rotating and attaching to each plate-like elastic member,
The third protrusion engages with the first recess, and the first protrusion engages with the third recess, and both ends of the sheet feed roller are sandwiched by the respective plate-like elastic members. 19. The sheet feeding device according to claim 18, wherein the sheet feeding and conveying surface of the sheet is exposed. 20. A sheet feeding unit for feeding a sheet material to an image forming unit for forming an image on the sheet material, wherein the sheet feeding unit includes a sheet holding unit for stacking and holding the sheet material; A holder base portion rotatably disposed in the vicinity of the portion, a sheet feeding roller having a sheet feeding conveyance surface for feeding a sheet material from the sheet holding portion and detachably held by the holder base portion; The image forming apparatus further comprises: a plurality of sheet feeding / conveying surfaces having the same shape. 21. The sheet feeding roller of the sheet feeding means has a substantially elliptical outer shape, and a pair of sheet feeding and conveying surfaces having the same shape are formed at a boundary of a straight line passing through two fixed points of the ellipse. 21. The image forming apparatus according to claim 20, wherein the image forming apparatus is held by the holder base so that the sheet feeding and conveying surface is exposed. 22. An image forming means storage space for accommodating the image forming means in a detachable manner, wherein the sheet feeding roller of the sheet feeding means has the image stored in the image forming means storage space. 22. The image forming apparatus according to claim 20, wherein the image forming device is disposed at a position adjacent to the forming device, and is attached to and detached from the holder base through the image forming device storage space from which the image forming device is taken out. . 23. The holder base portion of the sheet feeding means includes a pair of plate-like elastic members sandwiching both end surfaces of the sheet feeding roller, and both end surfaces of the sheet feeding roller and each plate-like elastic member. The image forming apparatus according to any one of claims 20 to 22, wherein a locking mechanism that detachably locks and holds both end surfaces of the sheet feeding roller is configured. 24. A pair of first protrusions formed on the same flat surface of both end surfaces of the paper feed roller on the paper feed front end side and on a straight line passing through the two fixed points of the elliptical shape. And a first locking means comprising a pair of first recesses formed on each plate-like elastic member and fitted with the first projections, respectively, wherein the paper feed roller of the sheet feeding means is provided. The respective plate-like elastic members are rotated by rotating about the respective first protrusions in a state where the respective first protrusions of the first locking means and the respective first recesses are fitted. The image forming apparatus according to claim 23, wherein the image forming apparatus is attached to and detached from the image forming apparatus. 25. The locking mechanism removes the paper feed roller from each of the plate-like elastic members, and rotates the paper feed roller by half a rotation about a straight line passing through the two fixed points of the ellipse to thereby make the respective paper feed rollers half-rotated. 25. The image forming apparatus according to claim 24, wherein each of the plate-shaped elastic members sandwiches the both ends of the sheet feeding roller and exposes the other sheet conveying surface by being attached to the sheet-shaped elastic member. 26. The first locking means of the locking mechanism, wherein each of the first projections is on both end sides of the paper feed roller, and each of the first recesses is on each of the plate-like elastic members. 26. The image forming apparatus according to claim 24, wherein the image forming apparatus is provided. 27. The locking mechanism according to claim 23, wherein the locking mechanism has a snap-fit portion in which the paper feed roller is snap-fitted to each of the plate-like elastic members. The image forming apparatus as described in the above. 28. The snap-fit portion of the locking mechanism is a second locking means including a second projection and a second recess fitted with the second projection. The image forming apparatus according to claim 27. 29. The second locking means, wherein the second projection is provided on at least one end face of the paper feed roller, and the second recess is provided on each of the plate-like elastic members. 29. The image forming apparatus according to claim 28, wherein the image forming apparatus is provided on at least one of the plate-like elastic members. 30. The image according to claim 29, wherein a groove for facilitating deformation in the vicinity of the second recess is formed near the second recess in the plate-like elastic member. Forming equipment. 31. The first projection is a pin-like projection, the second projection is a square projection, and one end of the first recess is open to the outer periphery of the plate-like elastic member. 31. The image forming apparatus according to claim 27, wherein the groove is a groove, and the second recess is a square recess corresponding to the square protrusion. 32. The second locking means in the second locking means.
A pair of protrusions are formed on both end surfaces on the rear end side of the sheet feeding roller at positions that are rotationally symmetric with respect to a straight line passing through the two fixed points of the ellipse. 29
32. The image forming apparatus according to any one of the above items. 33. The second locking means, wherein the second concave portion is provided only in one plate-like elastic member, and the other plate-like elastic member has a snap fit with the second protrusion. 33. A notch which is not formed.
The image forming apparatus as described in the above. 34. The second locking means in the second locking means.
33. The projection according to claim 29, wherein a pair of the projections are formed on the same end face side of the paper feed roller at positions respectively point-symmetric with respect to the center point of the elliptical shape. The image forming apparatus as described in the above. 35. A third locking device comprising: a third protrusion provided near the second protrusion; and a third recess configured to lock the third protrusion. 35. The image forming apparatus according to claim 28, further comprising a locking unit. 36. A third locking means in the locking mechanism, wherein the third projection is provided on the paper feed roller side,
The image forming apparatus according to claim 35, wherein the third concave portion is provided in at least one of the plate-like elastic members. 37. The third locking means in the third locking means.
37. The image forming apparatus according to claim 36, wherein the concave portion has an abutting portion that abuts the third projection portion when the sheet feeding roller is attached to each of the plate-shaped elastic members. 38. The third locking means in the third locking means.
38. The image forming apparatus according to claim 36, wherein the projection is formed on a straight line passing through the two fixed points of the ellipse. 39. The locking mechanism, wherein the third protrusion has the same shape as the first protrusion, the paper feed roller is removed from each of the plate-like elastic members, and the paper feed roller is half-closed. By rotating and attaching to each plate-like elastic member,
The third projection engages with the first recess, and the first projection engages with the third recess, and both ends of the sheet feeding roller are sandwiched by the respective plate-like elastic members. 39. The image forming apparatus according to claim 38, wherein a sheet feeding / conveying surface is exposed.